1

     AS FILED WITH THE SECURITIES AND EXCHANGE COMMISSION ON APRIL 17, 2001.
                                                      REGISTRATION NO. 333-

================================================================================
                       SECURITIES AND EXCHANGE COMMISSION
                             WASHINGTON, D.C. 20549

                                   ----------

                                    FORM S-4
                             REGISTRATION STATEMENT
                                      UNDER
                           THE SECURITIES ACT OF 1933

                                   ----------

                        PIONEER NATURAL RESOURCES COMPANY
             (Exact Name of Registrant as Specified in its Charter)



            DELAWARE                              1311                           75-2702753
                                                                     
(State or Other Jurisdiction of       (Primary standard industrial            (I.R.S. Employer
 Incorporation or Organization)       classification code number)           Identification No.)


                            1400 WILLIAMS SQUARE WEST
                            5205 NORTH O'CONNOR BLVD.
                               IRVING, TEXAS 77039
                                 (972) 444-9001
                        (Address, including zip code, and
                    telephone number, including area code, of
                    registrant's principal executive offices)

                                   ----------

                               SCOTT D. SHEFFIELD
                        PIONEER NATURAL RESOURCES COMPANY
                            1400 WILLIAMS SQUARE WEST
                            5205 NORTH O'CONNOR BLVD.
                               IRVING, TEXAS 77039
                                 (972) 444-9001
                (Name, address, including zip code, and telephone
               number, including area code, of agent for service)

                                   ----------

                                   COPIES TO:

     ROBERT L. KIMBALL                              BRIAN M. LIDJI
  VINSON & ELKINS L.L.P.                SAYLES, LIDJI & WERBNER, A PROFESSIONAL
3700 TRAMMELL CROW CENTER                             CORPORATION
     2001 ROSS AVENUE                           4400 RENAISSANCE TOWER
    DALLAS, TEXAS 75201                             1201 ELM STREET
      (214) 220-7700                              DALLAS, TEXAS 75270
                                                    (214) 939-8700

     APPROXIMATE DATE OF COMMENCEMENT OF PROPOSED SALE TO THE PUBLIC: As soon as
practicable after the effective date of this registration statement which
relates to the merger of limited partnerships with and into Pioneer Natural
Resources USA, Inc. pursuant to the merger agreement described in the enclosed
proxy statement/prospectus.

                                   ----------

     If the securities being registered on this form are being offered in
connection with the formation of a holding company and there is compliance with
General Instruction G, check the following box. [ ]

     If this form is filed to register additional securities for an offering
pursuant to Rule 462(b) under the Securities Act, check the following box and
list the Securities Act registration statement number of the earlier effective
registration statement for the same offering. [ ]

     If this form is a post-effective amendment filed pursuant to Rule 462(d)
under the Securities Act, check the following box and list the Securities Act
registration statement number of the earlier effective registration statement
for the same offering. [ ]

                         CALCULATION OF REGISTRATION FEE



=====================================================================================================================
                                                             PROPOSED MAXIMUM      PROPOSED MAXIMUM     AMOUNT OF
        TITLE OF EACH CLASS OF            AMOUNT TO BE           OFFERING              AGGREGATE       REGISTRATION
     SECURITIES TO BE REGISTERED          REGISTERED(1)     PRICE PER SHARE(2)     OFFERING PRICE(2)      FEE(2)
---------------------------------------------------------------------------------------------------------------------
                                                                                           
    Common Stock, $0.01 par value            5,122,138             $6.09              $31,200,000         $7,800
=====================================================================================================================


     (1) Based upon the registrant's estimate of the maximum number of shares
that might be issued in connection with the proposed merger transaction.

     (2) Estimated solely for the purpose of calculating the registration fee
pursuant to Rule 457(f), based on the book value of the unaffiliated partnership
interests to be cancelled in the transaction, computed as of the latest
practicable date, less the amount of cash to be paid by the registrant in the
transaction. A filing fee of $20,500 is being paid pursuant to the filing on the
date hereof by the registrant and Pioneer Natural Resources USA, Inc. of a
preliminary Schedule 13e-3. Pursuant to Rule 240.0-11(a)(2) of the Securities
Exchange Act of 1934, this amount has been credited against the amount that
would otherwise be payable in connection with this filing, resulting in no
additional payment herewith.

     THE REGISTRANT HEREBY AMENDS THIS REGISTRATION STATEMENT ON SUCH DATE OR
DATES AS MAY BE NECESSARY TO DELAY ITS EFFECTIVE DATE UNTIL THE REGISTRANT SHALL
FILE A FURTHER AMENDMENT WHICH SPECIFICALLY STATES THAT THIS REGISTRATION
STATEMENT SHALL THEREAFTER BECOME EFFECTIVE IN ACCORDANCE WITH SECTION 8(a) OF
THE SECURITIES ACT OF 1933 OR UNTIL THE REGISTRATION STATEMENT SHALL BECOME
EFFECTIVE ON SUCH DATE AS THE SECURITIES AND EXCHANGE COMMISSION, ACTING
PURSUANT TO SAID SECTION 8(a), MAY DETERMINE.

================================================================================

   2

                       PIONEER NATURAL RESOURCES USA, INC.
                            1400 WILLIAMS SQUARE WEST
                            5205 NORTH O'CONNOR BLVD.
                               IRVING, TEXAS 75039

                 NOTICE OF SPECIAL MEETINGS OF LIMITED PARTNERS
                          TO BE HELD ON       , 2001

To the Limited Partners of 46
Parker & Parsley Limited Partnerships:

     This is a notice that a special meeting of the limited partners of each of
the following 46 limited partnerships will be held on           , 2001, at 10:00
a.m., at the Dallas Marriott Las Colinas Hotel, Irving, Texas 75039:


                                                               
         Parker & Parsley 81-I, Ltd.                              Parker & Parsley 88-A Conv., L.P.
         Parker & Parsley 81-II, Ltd.                             Parker & Parsley 88-A, L.P.
         Parker & Parsley 82-I, Ltd.                              Parker & Parsley 88-B Conv., L.P.
         Parker & Parsley 82-II, Ltd.                             Parker & Parsley 88-B, L.P.
         Parker & Parsley 82-III, Ltd.                            Parker & Parsley 88-C Conv., L.P.
         Parker & Parsley 83-A, Ltd.                              Parker & Parsley 88-C, L.P.
         Parker & Parsley 83-B, Ltd.                              Parker & Parsley Producing Properties 88-A, L.P.
         Parker & Parsley 84-A, Ltd.                              Parker & Parsley Private Investment 88, L.P.
         Parker & Parsley 85-A, Ltd.                              Parker & Parsley 89-A Conv., L.P.
         Parker & Parsley 85-B, Ltd.                              Parker & Parsley 89-A, L.P.
         Parker & Parsley Private Investment 85-A, Ltd.           Parker & Parsley 89-B Conv., L.P.
         Parker & Parsley Selected 85 Private Investment, Ltd.    Parker & Parsley 89-B, L.P.
         Parker & Parsley 86-A, Ltd.                              Parker & Parsley Private Investment 89, L.P.
         Parker & Parsley 86-B, Ltd.                              Parker & Parsley 90-A Conv., L.P.
         Parker & Parsley 86-C, Ltd.                              Parker & Parsley 90-A, L.P.
         Parker & Parsley Private Investment 86, Ltd.             Parker & Parsley 90-B Conv., L.P.
         Parker & Parsley 87-A Conv., Ltd.                        Parker & Parsley 90-B, L.P.
         Parker & Parsley 87-A, Ltd.                              Parker & Parsley 90-C Conv., L.P.
         Parker & Parsley 87-B Conv., Ltd.                        Parker & Parsley 90-C, L.P.
         Parker & Parsley 87-B, Ltd.                              Parker & Parsley Private Investment 90, L.P.
         Parker & Parsley Producing Properties 87-A, Ltd.         Parker & Parsley 90 Spraberry Private Development, L.P.
         Parker & Parsley Producing Properties 87-B, Ltd.         Parker & Parsley 91-A, L.P.
         Parker & Parsley Private Investment 87, Ltd.             Parker & Parsley 91-B, L.P.


     Parker & Parsley Petroleum USA, Inc. and other predecessors of Pioneer
Natural Resources USA, Inc., a Delaware corporation that we call Pioneer USA,
sponsored each of the partnerships. Pioneer USA is the managing or sole general
partner of each of the partnerships. Pioneer USA is a direct 100% owned
subsidiary of Pioneer Natural Resources Company, a Delaware corporation that we
call Pioneer.

     The purpose of the special meeting for each partnership in which you own an
interest is for you to consider and vote on the following matters:

     1. A proposal to approve an Agreement and Plan of Merger dated as of      ,
2001, among Pioneer, Pioneer USA and each of the partnerships. Each partnership
that approves this proposal, which we call a participating partnership, will
merge with and into Pioneer USA, with Pioneer USA surviving the merger. Each
partnership interest of a participating partnership, other than Pioneer USA's
partnership interests, will be converted into shares of common stock, par value
$.01 per share, of Pioneer and an amount of cash. The number of shares of common
stock Pioneer will offer and the amount of cash to be paid for all partnership
interests of a participating partnership will be based on the participating
partnership's merger value. The merger value for a participating partnership is
equal to the sum of the present value of estimated future net revenues from the
partnership's oil and gas reserves and its net working capital, in each case as
of March 31, 2001. The amount of cash to be paid will equal 25% of the merger
value for a participating partnership. The remaining 75% of the merger value for
a participating partnership will be paid in shares of Pioneer common stock based
on the average closing price of the Pioneer common stock, as reported by the New
York Stock Exchange, for the ten trading days ending three business days before
the date of the special meeting for the partnership. For purposes of
illustration in this document, we have calculated the merger value based on each
partnership's working capital as of December 31, 2000, and the number of shares
to be issued based on an assumed average closing price of $18.00 per share of
Pioneer common stock. We will update the calculation of the merger value using
the March 31, 2001 working capital of each partnership before mailing this
document to the limited partners, and prior to the date of the special meeting
for each partnership, we will update the number of shares to be issued using the
actual average closing price of Pioneer common stock for the ten trading days
ending three business days before the date of the special meeting. The Pioneer
common stock and the cash payment will be allocated among the partners based on
the liquidation provisions of each partnership agreement. Pioneer will not issue
fractional shares to any limited partner upon completion of the merger of any
partnership. Instead, Pioneer will round any fractional shares of Pioneer common
stock up to the nearest whole share and will reduce the cash payment to a
limited partner of a participating partnership by the amount rounded up based on
the average closing price per share used in determining the number of shares of
Pioneer common stock to be offered. Pioneer USA will not receive any Pioneer
common stock or cash payment for its partnership interests in the participating
partnerships.


   3
     2. A proposal to amend the partnership agreement of each partnership to
permit the partnership's merger with Pioneer USA. If the amendment is not
approved, that partnership cannot merge into Pioneer USA even if the partners of
that partnership approve the merger agreement.

     3. A proposal (A) to approve the opinion issued to Pioneer USA by on behalf
of the limited partners of each partnership that neither the grant nor the
exercise of the right to approve the merger of the partnership by its limited
partners (1) will result in the loss of any limited partner's limited liability
or (2) will adversely affect the federal income tax classification of the
partnership or any of its limited partners and (B) to approve the selection of
as special legal counsel for the limited partners of each partnership to render
the legal opinion.

     4. Other business that properly comes before the special meeting or any
adjournments or postponements of the special meeting. We are not aware of any
other business for the special meeting.

     The accompanying proxy statement/prospectus contains information about each
merger, including the amount of Pioneer common stock that will be offered and
amount of cash that will be paid to limited partners per $1,000 initial
investment in each partnership, and descriptions of the merger agreement, the
merger amendment and the legal opinion of the special legal counsel for the
limited partners. The proxy statement/prospectus also contains a copy of the
merger agreement, the merger amendment and the legal opinion.

     Pioneer USA set the close of business on      , 2001, as the record date to
identify the limited partners who are entitled to notice of and to vote at each
special meeting or any adjournments or postponements of the special meeting.
During the ten business days before the special meeting, you may examine lists
of the limited partners of each partnership in which you own an interest at the
offices of Pioneer USA during normal business hours for any purpose relevant to
the special meeting for each partnership in which you own an interest.

     ON         , 2001, PIONEER USA'S BOARD OF DIRECTORS UNANIMOUSLY DETERMINED
THAT THE MERGER OF EACH PARTNERSHIP IN WHICH YOU OWN AN INTEREST IS ADVISABLE,
FAIR TO YOU AS AN UNAFFILIATED LIMITED PARTNER, AND IN YOUR BEST INTERESTS. THE
BOARD RECOMMENDS THAT YOU, AS AN UNAFFILIATED LIMITED PARTNER, VOTE FOR THE
MERGER AGREEMENT, THE MERGER AMENDMENT, THE SELECTION OF SPECIAL LEGAL COUNSEL
FOR THE LIMITED PARTNERS AND THAT COUNSEL'S LEGAL OPINION FOR EACH PARTNERSHIP
IN WHICH YOU OWN AN INTEREST. ALTHOUGH PIONEER USA'S BOARD OF DIRECTORS HAS
ATTEMPTED TO FULFILL ITS FIDUCIARY DUTIES TO YOU, PIONEER USA'S BOARD OF
DIRECTORS HAD CONFLICTING INTERESTS IN EVALUATING EACH MERGER BECAUSE EACH
MEMBER OF ITS BOARD OF DIRECTORS IS ALSO AN OFFICER OF PIONEER. Each partnership
requires a favorable vote of the holders of a majority of its limited
partnership interests to approve the merger agreement, the merger amendment, the
selection of special legal counsel for the limited partners and that counsel's
legal opinion, except that Parker & Parsley 91-A, L.P. and Parker & Parsley
91-B, L.P. each require the favorable vote of the holders, other than Pioneer
USA, of 66 2/3% of its limited partnership interests to approve those merger
proposals.

     IF YOU DO NOT SEND IN YOUR PROXY CARD OR VOTE AT THE SPECIAL MEETING FOR A
PARTNERSHIP IN WHICH YOU OWN AN INTEREST, IT WILL HAVE THE SAME EFFECT AS IF YOU
VOTED AGAINST THE MERGER OF THAT PARTNERSHIP.

     You are requested to sign, vote and date the enclosed proxy card and return
it promptly in the enclosed envelope, even if you expect to be present at each
special meeting for the partnerships in which you own an interest. If you give a
proxy, you can revoke it at any time before the special meeting for the
partnership as to which you are revoking your proxy. If you are present at the
special meeting for a partnership in which you own an interest, you may withdraw
your proxy and vote in person.

                                   By Order of the Board of Directors,

                , 2001
                                   Mark L. Withrow
                                   Director, Executive Vice President, General
                                   Counsel and Secretary



                                      -2-
   4

The information in this prospectus is not complete and may be changed. We may
not sell these securities until the registration statement filed with the
Securities and Exchange Commission is effective. This prospectus is not an offer
to sell these securities and it is not soliciting an offer to buy these
securities in any state where the offer or sale is not permitted.

                                                [PIONEER NATURAL RESOURCES LOGO]

PRELIMINARY PROXY STATEMENT/PROSPECTUS, SUBJECT TO COMPLETION, DATED APRIL 17,
2001

                        PIONEER NATURAL RESOURCES COMPANY
                       PIONEER NATURAL RESOURCES USA, INC.
                            1400 WILLIAMS SQUARE WEST
                            5205 NORTH O'CONNOR BLVD.
                               IRVING, TEXAS 75039

                                                                          , 2001

Dear Limited Partners:

     We at Pioneer Natural Resources USA, Inc. invite you to attend the special
meeting of limited partners for each partnership described below in which you
own an interest. Each special meeting will be held on  , 2001, at 10:00 a.m., at
the Dallas Marriott Las Colinas Hotel, Irving, Texas 75039. The purpose of each
special meeting is for you to vote on the merger of each partnership in which
you own partnership interests that, if completed, will result in your receiving
common stock of Pioneer Natural Resources Company, a Delaware corporation that
we call Pioneer, and cash for your partnership interests. If you and the other
limited partners of a partnership approve the merger of the partnership, the
partnership will be merged with and into Pioneer Natural Resources USA, Inc., a
Delaware corporation and 100% owned subsidiary of Pioneer that we call Pioneer
USA, with Pioneer USA surviving the merger.

     Pioneer and Pioneer USA desire to acquire 46 limited partnerships. We are a
direct 100% owned subsidiary of Pioneer and we are the managing or sole general
partner of each of the partnerships. Our predecessors, including Parker &
Parsley Petroleum USA, Inc., originally sponsored each of the partnerships. The
partnerships are Texas and Delaware limited partnerships. They were formed from
1981 through 1991 to acquire, develop and produce oil and gas reserves.

     We have retained Robert A. Stanger & Co., Inc., which we call Stanger, to
issue a fairness opinion in connection with the merger of each partnership.
Stanger's opinion is dated as of       , 2001 and, subject to the qualifications
stated in that opinion, states that the merger value for each partnership and
the allocation of the merger value of the partnership (1) to the limited
partners of the partnership as a group, (2) to the general partners of the
partnership as a group, (3) to Pioneer USA as the managing or sole general
partner of the partnership, (4) to the unaffiliated limited partners of the
partnership as a group and (5) to the unaffiliated limited partners of the
nonmanaging general partner, if any, of the partnership as a group, is fair to
the unaffiliated limited partners of the partnership and the unaffiliated
limited partners of the nonmanaging general partner, if any, of the partnership,
from a financial point of view. The written opinion of Stanger is contained in
this document. You should read all of it carefully.

     We can complete the merger of each partnership only if the holders of a
majority, or 66 2/3% for Parker & Parsley 91-A, L.P. and Parker & Parsley 91-B,
L.P., of its limited partnership interests approve the merger agreement, the
amendment to the partnership agreement to permit the merger, the selection of
special legal counsel for the limited partners and that counsel's legal opinion.
This document provides information about each proposed merger. It includes a
copy of the merger agreement, the merger amendment and the legal opinion of the
special legal counsel for the limited partners. This document also constitutes a
prospectus by Pioneer for up to an aggregate of 4,268,471 shares of Pioneer
common stock to be issued in the proposed merger transaction. Please give all of
this information your careful attention.

     YOUR VOTE IS IMPORTANT. Whether or not you plan to attend the special
meeting for each partnership in which you own an interest, please take the time
to vote by completing and mailing to us the enclosed proxy card. This will not
prevent you from revoking your proxy at any time prior to the special meeting
for each partnership in which you own an interest or from voting your
partnership interests in person if you later choose to attend the special
meeting for each partnership in which you own an interest.

     We intend to mail certificates representing shares of Pioneer common stock
and checks to the partners of each partnership that approves the merger
transaction promptly after completing the merger of the partnership.
Certificates representing partnership interests will be automatically cancelled,
and you will not have to surrender your certificates to receive the Pioneer
common stock and the cash payment.

     YOUR CERTIFICATE THAT YOU ARE NOT A FOREIGN PERSON, WHICH WE CALL A
CERTIFICATION OF NON-FOREIGN STATUS, IS IMPORTANT. Whether or not you plan to
vote on the merger of each partnership in which you own an interest, please take
the time to complete and return to us the enclosed certification of non-foreign
status. If we receive a properly completed certification of non-foreign status
from you, we will not withhold federal income taxes on the Pioneer common stock
and cash to be paid to you upon the merger of each partnership in which you own
an interest.

              Sincerely,


              Mark L. Withrow
              Director, Executive Vice President, General
              Counsel and Secretary


     YOU SHOULD CAREFULLY CONSIDER THE RISKS RELATING TO THE MERGER OF EACH
PARTNERSHIP IN WHICH YOU OWN AN INTEREST DESCRIBED IN "RISK FACTORS" BEGINNING
ON PAGE 17. THESE INCLUDE:

     o    THE MERGER VALUE FOR THE PARTNERSHIP DETERMINES THE AMOUNT OF PIONEER
          COMMON STOCK AND CASH YOU WILL RECEIVE IN THE MERGER OF THE
          PARTNERSHIP. PIONEER AND PIONEER USA DETERMINED EACH MERGER VALUE AND
          WILL NOT ADJUST IT FOR CHANGES IN PARTNERSHIP VALUE BEFORE THE MERGER
          IS COMPLETED.

     o    YOU WERE NOT INDEPENDENTLY REPRESENTED IN ESTABLISHING THE TERMS OF
          ANY MERGER.

     o    OUR BOARD OF DIRECTORS HAD CONFLICTING INTERESTS IN EVALUATING EACH
          MERGER BECAUSE EACH MEMBER OF OUR BOARD OF DIRECTORS IS ALSO AN
          OFFICER OF PIONEER.

     NEITHER THE SECURITIES AND EXCHANGE COMMISSION NOR ANY STATE SECURITIES
REGULATORS HAVE APPROVED ANY OF THE MERGERS, THE PIONEER COMMON STOCK TO BE
ISSUED IN EACH MERGER OR THE FAIRNESS OR THE MERITS OF EACH MERGER OR HAVE
DETERMINED WHETHER THE INFORMATION CONTAINED IN THIS DOCUMENT IS ACCURATE OR
ADEQUATE. ANY REPRESENTATION TO THE CONTRARY IS A CRIMINAL OFFENSE.

     This proxy statement/prospectus is dated         , 2001. It is first being
mailed to the limited partners on or about        , 2001.



   5

                        PIONEER NATURAL RESOURCES COMPANY

o    PROVED RESERVE BASE: 3.8 TRILLION CUBIC FEET EQUIVALENT OR 628 MILLION
     BARRELS OF OIL EQUIVALENT

o    RESERVE BALANCE: 50% GAS, 50% LIQUIDS (OIL AND NATURAL GAS LIQUIDS)

o    RESERVES/PRODUCTION RATIO: 14 YRS

o    DRILLING INVENTORY: 1,700+ LOCATIONS

o    EXPLORATION PROGRAM EXPECTED TO ADD NEW RESERVES AND PRODUCTION:

     o    DEEPWATER GULF OF MEXICO

     o    SOUTH AFRICA


                                     [MAP]


   6

                                TABLE OF CONTENTS





                                                             Page
                                                             ----
                                                          

QUESTIONS AND ANSWERS ABOUT THE
   MERGER OF EACH PARTNERSHIP ..............................   --
SUMMARY ....................................................    1
RISK FACTORS ...............................................   17
   Risk Factors Relating to the Merger of Each
   Partnership .............................................   17
     The Merger Values Involve Estimates
       that Will Not Be Adjusted ...........................   17
     The Number of Shares of Pioneer Common
       Stock the Limited Partners of Each
       Partnership Will Receive May Decrease
       Between Now and the Completion of the
       Merger of the Partnership ...........................   17
     Current Market Prices for Oil and Gas
       May Be Higher than the Merger Value
       for a Partnership, Which May Affect
       Deliverability of the Fairness Opinion ..............   17
     You Were Not Independently Represented
       in Establishing the Terms of the Merger
       of Each Partnership .................................   17
     The Interests of Pioneer, Pioneer USA and
       Their Directors and Officers May Differ
       From Your Interests .................................   18
     Pioneer USA Has Previously Offered Each
       Partnership for Sale to Others, But It Did
       Not Receive Any Formal Bids .........................   18
     Potential Litigation Challenging the Merger
       of a Partnership May Delay or Block the
       Merger ..............................................   18
     Repurchase Rights Terminate On Completion
       of the Mergers ......................................   18
     You Could be Bound by the Merger of Each
       Partnership in Which You Own an Interest
       Even If You Do Not Vote in Favor of
       the Merger ..........................................   19
   Risks Associated With an Investment in
   Pioneer .................................................   19
     Limited Partners Who Become Pioneer
       Stockholders Will Fundamentally Change
       the Nature of Their Investment ......................   19
     Pioneer Might Not Declare Dividends ...................   19
     Limited Partners Who Become Pioneer
       Stockholders May Be Diluted .........................   20
     Dividends Paid to Pioneer Stockholders Are
       Taxed at Two Levels .................................   20
     Pioneer's Business Activities Involve Risks ...........   20
SPECIAL FACTORS ............................................   21
   Background of the Merger of Each Partnership ............   21
   Reasons for the Merger of Each Partnership ..............   26
   Pioneer's Disclosure Relating to the Merger
     of Each Partnership ...................................   28
   Recommendation of Pioneer USA ...........................   28
   Fairness Opinion ........................................   29
   Summary Reserve Report ..................................   35
   Alternative Transactions to the Merger of
     Each Partnership ......................................   36
FORWARD-LOOKING STATEMENTS .................................   38
METHOD OF DETERMINING MERGER
   VALUE FOR EACH PARTNERSHIP AND
   AMOUNT OF PIONEER COMMON STOCK
   AND CASH OFFERED ........................................   39
   Components of Merger Value for Each
     Partnership ...........................................   39
   Allocation of Merger Value for Each
     Partnership Among Partners of the
     Partnership ...........................................   40
   Other Methods of Determining Merger
     Values ................................................   41
   Information Sources .....................................   41
THE MERGER OF EACH PARTNERSHIP .............................   43
   General .................................................   43
   Legal Opinion for Limited Partners ......................   43
   Distribution of Pioneer Common Stock and
     Cash Payment ..........................................   44
   Fractional Shares .......................................   44
   Material U.S. Federal Income Tax
     Consequences ..........................................   44
   Accounting Treatment ....................................   46
   Effect of Merger of Each Partnership on
     Limited Partners Who Do Not Vote in
     Favor of the Merger; No Appraisal or
     Dissenters' Rights ....................................   46
   Future of Nonparticipating Partnerships .................   47
   Nonmanaging General Partners of Some
     Partnerships ..........................................   47
   Third Party Offers ......................................   48
   Merger Amendment ........................................   48
   Termination of Registration and Reporting
     Requirements ..........................................   48
   Elimination of a Fairness Opinion
     Requirement That Would Otherwise
     Benefit Pioneer USA ...................................   48
   Source of Funds .........................................   49
   Payment of Expenses and Fees ............................   50
THE MERGER AGREEMENT .......................................   51
   Structure; Effective Time ...............................   51
   Effects of the Mergers ..................................   51
   Conduct of Business Prior to the Mergers ................   51
   Other Agreements ........................................   51
   Representations and Warranties of
     Pioneer, Pioneer USA and Each
     Partnership ...........................................   52
   Conditions to the Merger of Each Partnership ............   52
   Termination of the Merger Agreement and
     the Merger of Any Partnership .........................   53
   Amendments; Waivers .....................................   54
THE SPECIAL MEETINGS .......................................   55
   Time and Place; Purpose .................................   55
   Record Date; Voting Rights and Proxies ..................   55
   Revocation of Proxies ...................................   56
   Solicitation of Proxies .................................   57
   Quorum ..................................................   57
   Required Vote; Broker Non-Votes .........................   57
   Participation by Assignees ..............................   58
   Special Requirements for Some Limited
     Partners ..............................................   58
   Validity of Proxy Cards .................................   58
   Local Laws ..............................................   58
COMPARATIVE PER SHARE MARKET
   PRICE AND DIVIDEND INFORMATION ..........................   59
INTERESTS OF PIONEER, PIONEER USA
   AND THEIR DIRECTORS AND
   OFFICERS ................................................   60
   Conflicting Duties of Pioneer USA, Individually
     and as General Partner ................................   60



                                      -i-
   7



                                                             Page
                                                             ----
                                                          

   Pioneer USA's Employees Provide Services
     to the Partnerships ...................................   60
   Financial Interests of Directors and Officers ...........   60
   The Partnerships Pay Operator Fees to
     Pioneer USA ...........................................   60
OWNERSHIP OF PARTNERSHIP
   INTERESTS ...............................................   61
TRANSACTIONS AMONG THE
   PARTNERSHIPS, PIONEER, PIONEER USA
   AND THEIR DIRECTORS AND
   OFFICERS ................................................   61
MANAGEMENT .................................................   62
   Pioneer .................................................   62
   Pioneer USA .............................................   63
PIONEER ....................................................   65
   Key Projects to Increase Production .....................   65
   More Information ........................................   65
THE PARTNERSHIPS ...........................................   66
   General .................................................   66
   The Drilling Partnerships ...............................   66
   The Income Partnerships .................................   67
COMPARISON OF RIGHTS OF
   STOCKHOLDERS AND PARTNERS ...............................   68
   General .................................................   68
   Summary Comparison of Terms of Shares of
     Pioneer Common Stock and Partnership
     Interests .............................................   68
LEGAL MATTERS ..............................................   73
INDEPENDENT AUDITORS AND
   INDEPENDENT PETROLEUM
   CONSULTANTS .............................................   73
WHERE YOU CAN FIND MORE
   INFORMATION .............................................   74
COMMONLY USED OIL AND
   GAS TERMS ...............................................   76
UNAUDITED PRO FORMA COMBINED
   FINANCIAL STATEMENTS ....................................  P-1




                               LIST OF APPENDICES



                                                                                                   Appendix
                                                                                                   --------
                                                                                             
General Information Relating to Each Partnership..........................................             A

  Table 1      Jurisdiction of Organization, Initial Subscription Price for Each
               Unit, Initial Investment by Limited Partners and Number of
               Limited Partners as of March 31, 2001

  Table 2      Aggregate Merger Value as of March 31, 2001

  Table 3      Merger Value Attributable to Partnership Interests of Limited
               Partners Per $1,000 Investment as of March 31, 2001

  Table 4      Ownership Percentage and Merger Value Attributable to Nonmanaging
               General Partners Other Than Pioneer USA as of March 31, 2001

  Table 5      Ownership Percentage and Merger Value Attributable to Pioneer USA
               in Its Capacities as General Partner, Nonmanaging General Partner
               and Limited Partner as of March 31, 2001

  Table 6      Voting Percentage and Initial Investment Owned by Pioneer USA in
               Its Capacity as a Limited Partner as of March 31, 2001

  Table 7      Historical Quarterly Partnership Distributions to the Limited
               Partners Per $1,000 Investment from Inception through March 31,
               2001

  Table 8      Annual Repurchase Prices and Aggregate Annual Repurchase Payments

  Table 9      Participation in Costs and Revenues of Each Partnership

  Table 10     Average Oil, Natural Gas Liquids and Gas Sales Prices and
               Production Costs for the Three Months Ended March 31, 2001 and
               2000 and the Years Ended December 31, 2000, 1999 and 1998

  Table 11     Proved Reserves Attributable to Pioneer USA, Nonmanaging General
               Partners and Limited Partners as of December 31, 2000

  Table 12     Proved Reserves Attributable to Pioneer USA, Nonmanaging General
               Partners and Limited Partners as of March 31, 2001

  Table 13     Oil, Natural Gas Liquids and Gas Production for the Three Months
               Ended March 31, 2001 and 2000 and the Years Ended December 31,
               2000, 1999 and 1998

  Table 14     Productive Wells and Developed Acreage as of December 31, 2000

  Table 15     Recent Trades of Partnership Interests Per $1,000 Investment for
               the Three Months Ended March 31, 2001 and the Years Ended
               December 31, 2000 and 1999

Summary Reserve Report of Williamson Petroleum Consultants, Inc. for the Partnerships.....             B

Form of Fairness Opinion of Robert A. Stanger & Co., Inc..................................             C

The Merger Proposals......................................................................             D

Form of Agreement and Plan of Merger......................................................             E



                                      -ii-
   8

     WE HAVE PREPARED A SEPARATE SUPPLEMENT TO THIS DOCUMENT FOR EACH
PARTNERSHIP. EACH SUPPLEMENT INCLUDES:

     o    A TABLE CONTAINING:

          -    THE AGGREGATE INITIAL INVESTMENT BY THE LIMITED PARTNERS

          -    THE AGGREGATE HISTORICAL LIMITED PARTNER DISTRIBUTIONS THROUGH
               MARCH 31, 2001

          -    THE AGGREGATE MERGER VALUE ATTRIBUTABLE TO PARTNERSHIP INTERESTS
               OF LIMITED PARTNERS, EXCLUDING PIONEER USA

          -    THE MERGER VALUE PER $1,000 LIMITED PARTNER INVESTMENT AS OF
               MARCH 31, 2001

          -    THE MERGER VALUE PER $1,000 LIMITED PARTNER INVESTMENT AS A
               MULTIPLE OF DISTRIBUTIONS FOR THE 12 MONTHS ENDED MARCH 31, 2001

          -    THE BOOK VALUE PER $1,000 LIMITED PARTNER INVESTMENT AS OF MARCH
               31, 2001 AND AS OF DECEMBER 31, 2000

          -    THE GOING CONCERN VALUE PER $1,000 LIMITED PARTNER INVESTMENT AS
               OF MARCH 31, 2001

          -    THE LIQUIDATION VALUE PER $1,000 LIMITED PARTNER INVESTMENT AS OF
               MARCH 31, 2001

          -    THE ORDINARY TAX LOSS PER $1,000 LIMITED PARTNER INVESTMENT IN
               YEAR OF INITIAL INVESTMENT

     o    INFORMATION ABOUT THE LEGAL OPINION FOR THE LIMITED PARTNERS

     o    FOR EACH PARTNERSHIP THAT IS SUBJECT TO THE REPORTING REQUIREMENTS OF
          THE SECURITIES AND EXCHANGE COMMISSION, WHICH WE CALL A REPORTING
          PARTNERSHIP, THE PARTNERSHIP'S QUARTERLY REPORT ON FORM 10-Q,
          INCLUDING MANAGEMENT'S DISCUSSION AND ANALYSIS OF FINANCIAL CONDITION
          AND RESULTS OF OPERATIONS, FOR THE THREE MONTHS ENDED MARCH 31, 2001

     o    FOR EACH REPORTING PARTNERSHIP, THE PARTNERSHIP'S ANNUAL REPORT ON
          FORM 10-K, INCLUDING MANAGEMENT'S DISCUSSION AND ANALYSIS OF FINANCIAL
          CONDITION AND RESULTS OF OPERATIONS, FOR THE YEAR ENDED DECEMBER 31,
          2000

     o    FOR EACH PARTNERSHIP THAT IS NOT SUBJECT TO THE REPORTING REQUIREMENTS
          OF THE SECURITIES AND EXCHANGE COMMISSION, WHICH WE CALL A
          NONREPORTING PARTNERSHIP, THE PARTNERSHIP'S FINANCIAL STATEMENTS,
          INCLUDING MANAGEMENT'S DISCUSSION AND ANALYSIS OF FINANCIAL CONDITION
          AND RESULTS OF OPERATIONS, FOR THE THREE MONTHS ENDED MARCH 31, 2001

     o    FOR EACH NONREPORTING PARTNERSHIP, THE PARTNERSHIP'S FINANCIAL
          STATEMENTS, INCLUDING MANAGEMENT'S DISCUSSION AND ANALYSIS OF
          FINANCIAL CONDITION AND RESULTS OF OPERATIONS, FOR THE YEAR ENDED
          DECEMBER 31, 2000

     o    SELECTED HISTORICAL FINANCIAL DATA FOR THE PARTNERSHIP FOR THE THREE
          MONTHS ENDED MARCH 31, 2001 AND 2000 AND THE FIVE YEARS ENDED DECEMBER
          31, 2000

THE SUPPLEMENT CONSTITUTES AN INTEGRAL PART OF THIS DOCUMENT FOR EACH
PARTNERSHIP. PLEASE CAREFULLY READ ALL OF THE SUPPLEMENTS FOR THE PARTNERSHIPS
IN WHICH YOU ARE A LIMITED PARTNER.


                                     -iii-
   9

           QUESTIONS AND ANSWERS ABOUT THE MERGER OF EACH PARTNERSHIP



Q: HOW DO I VOTE?

A: After reading this document, please fill out and sign your proxy card. Then
mail your signed proxy card in the enclosed return envelope as soon as possible
so that your partnership interests will be represented at the special meeting
for each partnership in which you own an interest.

Q: WHAT HAPPENS IF I DO NOT RETURN A PROXY CARD?

A: The failure to return your proxy card will have the same effect as voting
against the merger for each partnership in which you own an interest.

Q: MAY I VOTE IN PERSON?

A: Yes. You may attend the special meeting for each partnership in which you own
an interest and vote your partnership interests in person, rather than signing
and mailing your proxy card.

Q: MAY I CHANGE MY VOTE AFTER I HAVE MAILED MY SIGNED PROXY CARD?

A: Yes. You may revoke your vote at any time before your proxy is voted at the
special meeting for each partnership in which you own an interest by following
the instructions beginning on page 55. You then may either change your vote by
sending in a new proxy card or by attending the special meeting for each
partnership in which you own an interest and voting in person.

Q: IF MY PARTNERSHIP INTERESTS ARE HELD IN A RETIREMENT ACCOUNT BY A CUSTODIAN,
WILL MY CUSTODIAN VOTE MY PARTNERSHIP INTERESTS FOR ME?

A: Your custodian will not be able to vote your partnership interests. You
should refer to the instructions included on your proxy card to vote your
partnership interests.

Q: SHOULD I SEND IN MY CERTIFICATES FOR MY PARTNERSHIP INTERESTS NOW?

A: No. If the merger of a partnership in which you own an interest is completed,
your certificates representing your partnership interests in that partnership
will be automatically cancelled. We will automatically mail checks and
certificates representing Pioneer common stock issued to you on completion of
the merger of that partnership.

Q: AM I ENTITLED TO APPRAISAL OR DISSENTERS' RIGHTS?

A: No. You will not have any appraisal or dissenters' rights in connection with
the merger of any partnership in which you own an interest.

Q: WHAT HAPPENS TO MY FUTURE CASH DISTRIBUTIONS?

A: Since your partnership interests in participating partnerships will be
cancelled upon completion of the merger of each such partnership, you will not
receive any future distributions on those interests. Pioneer's board of
directors did not declare dividends to the holders of Pioneer common stock
during 1999, 2000 or the three months ended March 31, 2001. The amount of
dividends, if any, paid by Pioneer in the future will depend on business
conditions, its financial condition and earnings, and other factors.

Q: WHO CAN HELP ANSWER MY QUESTIONS?

A: If you have any questions about the merger of any of the partnerships in
which you own an interest, please call Pioneer's information agent,            ,
at (  )    -     .


   10
                                     SUMMARY

     This summary and the preceding questions and answers highlight some of the
information from this document and may not contain all of the information that
is important to you. To understand the merger of each partnership in which you
own an interest and to obtain a more detailed description of the legal terms of
each such merger, you should carefully read this entire document, the related
partnership supplements, and the documents described in "Where You Can Find More
Information" on page 74 . For definitions of oil and gas terms used in this
document, see "Commonly Used Oil and Gas Terms" on page 76.

     When we use the terms "Pioneer USA," "we," "us" or "our," we are referring
to your sole or managing general partner, Pioneer Natural Resources USA, Inc.,
including its consolidated subsidiaries and predecessors, unless the context
otherwise requires. When we use the term "Pioneer," we are referring to Pioneer
Natural Resources Company. When we use the term "merger proposals," we are
referring to the proposals to approve the merger agreement, the merger
amendment, the selection of special legal counsel for the limited partners and
the legal opinion of that counsel. When we use the term "participating
partnership," we are referring to each partnership the limited partners of which
approve the merger proposals.

                                   THE MERGERS

     Pioneer proposes to acquire each partnership by merging each partnership
into us. We will be the survivor of each merger. The partnership interests of
each participating partnership, other than our interests, will be converted into
Pioneer common stock and cash.

     The number of shares of common stock Pioneer will offer and the amount of
cash to be paid for all partnership interests of a participating partnership
will be based on the merger value for the partnership as described below. The
amount of cash to be paid will equal 25% of the merger value for a participating
partnership. The remaining 75% of the merger value for a participating
partnership will be paid in shares of Pioneer common stock based on the average
closing price of the Pioneer common stock, as reported by the New York Stock
Exchange, for the ten trading days ending three business days before the date of
the special meeting for the partnership. Pioneer and Pioneer USA determined the
merger value for each partnership primarily based on the present value of
estimated future net revenues from the partnership's oil and gas reserves at
March 31,2001. In determining the present value, Pioneer and Pioneer USA used
(1) a five-year New York Mercantile Exchange, or NYMEX, futures price for oil
and gas as of March 30, 2001 with prices held constant after year five at the
year five price, less standard industry adjustments, (2) historical operating
costs adjusted only for those items affected by commodity prices, such as
production taxes and ad valorem taxes, and (3) a 13.5% discount rate. For 2001,
the oil and gas prices were based on the average NYMEX futures price for the
nine-month period beginning on April 1, 2001 and ending December 31, 2001. See
the table on page 6 for the NYMEX futures prices. See "Method of Determining
Merger Value For Each Partnership and Amount of Pioneer Common Stock and Cash
Offered -- Components of Merger Value For Each Partnership" on page 39 of this
document for information on the basis of pricing. In addition, each
partnership's merger value includes its net working capital as of March 31,
2001. The Pioneer common stock and the cash payment will be allocated among the
partners of a participating partnership based on the liquidation provisions of
the partnership agreement of the partnership.

     On pages 4 and 5 of this document is a table that shows important
information about each partnership, including the amount of Pioneer common stock
that will be offered and cash that will be paid in the merger for each $1,000 of
initial investment for that partnership. For purposes of illustration in this
document, we have calculated the merger value based on each partnership's
working capital as of December 31, 2000, and the number of shares to be issued
based on an assumed average closing price of $18.00 per share of Pioneer common
stock. We will update the calculation of the merger value using the March 31,
2001 working capital of each partnership before mailing this document to the
limited partners, and prior to the date of the special meeting for each
partnership, we will update the number of shares to be issued using the actual
average closing price of Pioneer common stock for the ten trading days ending
three business days before the date of the special meeting.

     Pioneer and Pioneer USA agreed to structure the transaction as a merger of
each partnership instead of as a property sale followed by liquidation of each
partnership because the merger will:

     o    require fewer legal documents;

     o    reduce filing fees and other costs; and

     o    result in the same amount of Pioneer common stock and cash to the
          limited partners as would a property sale and liquidation using the
          same commodity prices.

     Pioneer and Pioneer USA expect to sign the merger agreement as soon as the
Securities and Exchange Commission clears this document for mailing to the
limited partners. However, if the oil and gas commodity prices materially
increase or decrease from the prices used in calculating the merger value for
any partnership, Pioneer or Pioneer USA might abandon the proposed merger of the
partnership before submitting the merger proposals to the limited partners for
approval. In addition, Pioneer may abandon the proposed merger of any or all of
the partnerships if an event occurs that causes or results in a material adverse
effect, among other things, on the price of Pioneer common stock, on the market
prices for oil and gas generally or on the oil and gas industry generally.
   11

                                  THE COMPANIES

PIONEER NATURAL RESOURCES COMPANY
1400 Williams Square West
5205 North O'Connor Blvd.
Irving, Texas 75039
(972) 444-9001

     Pioneer is a large, independent exploration and production company with
total proved reserves equivalent to 3.8 trillion cubic feet of natural gas, or
628 million barrels of oil. Pioneer's proved reserves are balanced equally
between natural gas and oil, and Pioneer has a reserves-to-production ratio of
14 years. Sixty-seven percent of Pioneer's proved reserves are in three U.S.
areas: the Hugoton gas field, the West Panhandle gas field, and the Spraberry
oil and natural gas field. Pioneer also has properties in East Texas, the Gulf
Coast, and the offshore Gulf of Mexico as well as in Argentina, Canada, South
Africa, and Gabon. Pioneer seeks to increase net asset value and production by
combining lower risk development drilling with higher-risk exploration activity.

     Pioneer's common stock is traded on the New York Stock Exchange and the
Toronto Stock Exchange under the symbol "PXD." Pioneer prepared this document to
offer its common stock and cash to you. See "Pioneer" on page 65 of this
document for more information about Pioneer.

     Pioneer files annual, quarterly and special reports, proxy statements and
other information with the Securities and Exchange Commission. Those SEC filings
are available to you in the same manner as each reporting partnership's
information. See "Where You Can Find More Information" on page 74 of this
document.

PIONEER NATURAL RESOURCES USA, INC.
1400 Williams Square West
5205 North O'Connor Blvd.
Irving, Texas 75039
(972) 444-9001

     We prepared this document to solicit your proxy. We are a 100% owned
subsidiary of Pioneer. We directly own almost all of Pioneer's United States oil
and gas properties.

THE PARTNERSHIPS
c/o Pioneer Natural Resources USA, Inc.
1400 Williams Square West
5205 North O'Connor Blvd.
Irving, Texas 75039
(972) 444-9001

     The name of each partnership is found in the table beginning on page 4.
Each partnership produces and sells oil and gas. Each partnership was formed to
provide the general and limited partners cash flow from operations and, in some
cases, tax incentives. See the supplement to this document for each of your
partnerships for specific information about the partnership, including the
merger value as a multiple of distributions for the 12 months ended March 31,
2001. As a result of each partnership's oil and gas operations, each partnership
distributes cash to the limited and general partners from the partnership's net
cash flows. These distributions are made quarterly, unless sufficient cash is
not available.

     The partnerships' properties consist of interests in approximately 1,100
oil and gas wells that are located primarily in the Spraberry field of the
Permian Basin of West Texas. We operate most of the partnerships' wells. At
December 31, 2000, the partnerships' combined total proved reserves were 33.6
million barrels of oil equivalent, or MMBOE, consisting of 27.3 million barrels,
or MMBbls, of oil and natural gas liquids and 37.6 billion cubic feet, or Bcf,
of natural gas. Approximately 93% of the reserves are attributable to the
limited partners' partnership interests, excluding partnership interests we
directly own. Approximately 81% of the total proved reserves attributable to the
properties are oil and liquids, and 19% are natural gas, based on six Mcf of gas
being equivalent to one Bbl of oil. See "The Partnerships" on page 66 of this
document for more information about the partnerships.

                        SUMMARY TABLE -- MERGER VALUE AND
                        AMOUNT OF INITIAL LIMITED PARTNER
                                INVESTMENT REPAID

     The table on pages 4 and 5 contains the following summary information for
each partnership:

o    the aggregate merger value attributable to:

     -    Pioneer USA's partnership interests, whether general or limited;

     -    the partnership interests of the unaffiliated limited partners of the
          nonmanaging general partner, if any, of each partnership;

     -    the limited partners' partnership interests, including the number of
          shares of Pioneer common stock and the amount of cash offered to the
          limited partners other than Pioneer USA;

o    for each $1,000 initial limited partner investment in the partnership:

     -    the number of shares of Pioneer common stock offered;

     -    the amount of cash that will be paid;

     -    the merger value;

     -    the total historical cash distributions through March 31, 2001; and

     -    the total amount of initial investment by the limited partners that
          has been repaid, after giving effect to the merger of the partnership,
          stated in dollars and as a percentage; and

o    the aggregate reserve value attributable to the limited partners other than
     Pioneer USA per barrel of oil equivalent, or BOE.



                                      -2-
   12

     This information is based on assumptions. You should read the following
table together with the detailed information in Table 2 and Table 3 of Appendix
A to this document. For purposes of illustration in this document, we have
calculated the merger value based on each partnership's working capital as of
December 31, 2000, and the number of shares to be issued based on an assumed
average closing price of $18.00 per share of Pioneer common stock. We will
update the calculation of the merger value using the March 31, 2001 working
capital of each partnership before mailing this document to the limited
partners, and prior to the date of the special meeting for each partnership, we
will update the number of shares to be issued using the actual average closing
price of Pioneer common stock for the ten trading days ending three business
days before the date of the special meeting.

     Interests in some partnerships were sold in units at prices other than
$1,000. We have presented this information based on a $1,000 initial investment
for ease of use and comparison among partnerships. You should not assume that
the amount shown per $1,000 investment is the same as the value or amount
attributable to a single unit investment. See Table 1 of Appendix A to this
document for the initial subscription price for each unit.




                                      -3-
   13

               SUMMARY TABLE -- MERGER VALUE AND AMOUNT OF INITIAL
                       LIMITED PARTNER INVESTMENT REPAID




                                                                                                                   PER $1,000
                                                                                                                     INITIAL
                                                                                                                     LIMITED
                                                                                                                     PARTNER
                                                             AGGREGATE MERGER VALUE                                INVESTMENT
                                  ----------------------------------------------------------------------------    ------------
                                                  NONMANAGING
                                                    GENERAL
                                  PIONEER USA       PARTNERS                   LIMITED PARTNERS
                                  ------------    ------------    --------------------------------------------
                                                                   NUMBER OF                                       NUMBER OF
                                                                   SHARES OF                                       SHARES OF
                                                                    PIONEER                                         PIONEER
                                   AGGREGATE       AGGREGATE        COMMON                         AGGREGATE        COMMON
                                     MERGER          MERGER          STOCK           CASH            MERGER          STOCK
PARTNERSHIP NAME                     VALUE           VALUE         OFFERED(a)       PAYMENT          VALUE         OFFERED(a)
----------------                  ------------    ------------    ------------    ------------    ------------    ------------
                                                                                                
Parker & Parsley 81-I, Ltd.       $    224,965    $     16,195          26,023    $    156,126    $    624,540            3.73
Parker & Parsley 81-II,                145,382           5,948          19,939         119,617         478,519            3.11
Ltd.
Parker & Parsley 82-I, Ltd.            394,878          13,776          35,945         215,657         862,667            3.41
Parker & Parsley 82-II,                404,903          12,591          48,327         289,956       1,159,842            4.10
Ltd.
Parker & Parsley 82-III,               302,259           9,856          32,361         194,158         776,656            5.00
Ltd.
Parker & Parsley 83-A, Ltd.            922,900          36,351         108,794         652,761       2,611,053            5.78
Parker & Parsley 83-B, Ltd.          1,201,169          46,876         141,017         846,098       3,384,404            6.27
Parker & Parsley 84-A, Ltd.          1,236,369          54,433         153,519         921,093       3,684,435            8.07
Parker & Parsley 85-A, Ltd.             40,356              --          55,790         334,727       1,338,947            5.92
Parker & Parsley 85-B, Ltd.             19,800              --          47,173         283,024       1,132,138            5.95
Parker & Parsley Private
Investment 85-A, Ltd.                   47,205              --          56,294         337,744       1,351,036           11.54
Parker & Parsley Selected
85 Private Investment, Ltd.             24,312              --          36,664         219,965         879,917            7.95
Parker & Parsley 86-A, Ltd.             23,089              --          70,725         424,332       1,697,382            7.01
Parker & Parsley 86-B, Ltd.             65,880              --         155,342         932,030       3,728,186            9.09
Parker & Parsley 86-C, Ltd.             41,460              --         130,394         782,358       3,129,450            6.77
Parker & Parsley Private
Investment 86, Ltd.                     12,414              --          51,210         307,247       1,229,027           10.41
Parker & Parsley 87-A
Conv., Ltd.                             13,894              --          29,913         179,465         717,899            7.83
Parker & Parsley 87-A, Ltd.             87,422              --         223,829       1,342,966       5,371,888            7.82
Parker & Parsley 87-B
Conv., Ltd.                             11,819              --          40,504         243,016         972,088            8.25
Parker & Parsley 87-B, Ltd.             49,125              --         165,489         992,930       3,971,732            8.26
Parker & Parsley Producing
Properties 87-A, Ltd.                   35,767              --         109,019         654,091       2,616,433            8.96
Parker & Parsley Producing
Properties 87-B, Ltd.                   58,764              --          92,028         552,162       2,208,666           15.34
Parker & Parsley Private
Investment 87, Ltd.                     27,958              --         115,326         691,941       2,767,809           11.00
Parker & Parsley 88-A
Conv., L.P.                             21,067              --          37,204         223,208         892,880            9.94
Parker & Parsley 88-A, L.P.             72,602              --         127,139         762,810       3,051,312            9.96
Parker & Parsley 88-B
Conv., L.P.                             17,558              --          46,635         279,800       1,119,230           12.90
Parker & Parsley 88-B, L.P.             57,127              --         114,341         686,040       2,744,178           12.91
Parker & Parsley 88-C
Conv., L.P.                             11,866              --          37,825         226,943         907,793           11.12


                                                PER $1,000 INITIAL LIMITED PARTNER INVESTMENT
                                  ----------------------------------------------------------------------------

                                                                                       AMOUNT OF INITIAL
                                                                                       INVESTMENT REPAID
                                                                                  ----------------------------
                                                                                                                     LIMITED
                                                                 DISTRIBUTIONS                                      PARTNERS'
                                                                     FROM                                           AGGREGATE
                                                                   INCEPTION                                         RESERVE
                                     CASH            MERGER         THROUGH                                           VALUE
PARTNERSHIP NAME                    PAYMENT          VALUE          3/31/01            $              %              PER BOE
----------------                  ------------    ------------   -------------    ------------    ------------     ------------
                                                                                                
Parker & Parsley 81-I, Ltd.       $      22.38    $      89.51    $     642.79    $     732.30           73.23%    $       3.46
Parker & Parsley 81-II,                  18.68           74.71          828.66          903.37           90.34%            3.07
Ltd.
Parker & Parsley 82-I, Ltd.              20.47           81.87          970.46        1,052.33          105.23%            3.15
Parker & Parsley 82-II,                  24.57           98.29        1,128.93        1,227.22          122.72%            3.55
Ltd.
Parker & Parsley 82-III,                 30.00          120.01          967.35        1,087.36          108.74%            3.40
Ltd.
Parker & Parsley 83-A, Ltd.              34.67          138.67        1,307.66        1,446.33          144.63%            3.12
Parker & Parsley 83-B, Ltd.              37.62          150.46        1,512.86        1,663.32          166.33%            3.12
Parker & Parsley 84-A, Ltd.              48.44          193.75        1,444.57        1,638.32          163.83%            3.11
Parker & Parsley 85-A, Ltd.              35.51          142.05          734.28          876.33           87.63%            3.40
Parker & Parsley 85-B, Ltd.              35.69          142.77          929.52        1,072.29          107.23%            3.53
Parker & Parsley Private
Investment 85-A, Ltd.                    69.21          276.85        1,096.30        1,373.15          137.32%            3.77
Parker & Parsley Selected
85 Private Investment, Ltd.              47.72          190.87          931.67        1,122.54          112.25%            3.35
Parker & Parsley 86-A, Ltd.              42.03          168.12        1,340.81        1,508.93          150.89%            3.34
Parker & Parsley 86-B, Ltd.              54.57          218.28        1,544.15        1,762.43          176.24%            3.63
Parker & Parsley 86-C, Ltd.              40.63          162.51        1,456.59        1,619.10          161.91%            3.37
Parker & Parsley Private
Investment 86, Ltd.                      62.45          249.80        1,594.84        1,844.64          184.46%            3.52
Parker & Parsley 87-A
Conv., Ltd.                              46.97          187.88        1,300.14        1,488.02          148.80%            3.55
Parker & Parsley 87-A, Ltd.              46.90          187.59        1,300.21        1,487.80          148.78%            3.57
Parker & Parsley 87-B
Conv., Ltd.                              49.51          198.02        1,221.48        1,419.50          141.95%            3.42
Parker & Parsley 87-B, Ltd.              49.54          198.15        1,221.55        1,419.70          141.97%            3.42
Parker & Parsley Producing
Properties 87-A, Ltd.                    53.75          214.99          958.64        1,173.63          117.36%            3.45
Parker & Parsley Producing
Properties 87-B, Ltd.                    92.07          368.26        1,080.14        1,448.40          144.84%            3.63
Parker & Parsley Private
Investment 87, Ltd.                      66.03          264.10        1,537.63        1,801.73          180.17%            3.32
Parker & Parsley 88-A
Conv., L.P.                              59.64          238.55        1,079.24        1,317.79          131.78%            3.54
Parker & Parsley 88-A, L.P.              59.77          239.09        1,079.34        1,318.43          131.84%            3.54
Parker & Parsley 88-B
Conv., L.P.                              77.38          309.52        1,082.16        1,391.68          139.17%            3.66
Parker & Parsley 88-B, L.P.              77.43          309.73        1,082.20        1,391.93          139.19%            3.66
Parker & Parsley 88-C
Conv., L.P.                              66.73          266.92        1,010.63        1,277.55          127.76%            3.60




                                      -4-
   14



                                                                                                                   PER $1,000
                                                                                                                     INITIAL
                                                                                                                     LIMITED
                                                                                                                     PARTNER
                                                             AGGREGATE MERGER VALUE                                INVESTMENT
                                  ----------------------------------------------------------------------------    ------------
                                                  NONMANAGING
                                                    GENERAL
                                  PIONEER USA       PARTNERS                   LIMITED PARTNERS
                                  ------------    ------------    --------------------------------------------
                                                                   NUMBER OF                                       NUMBER OF
                                                                   SHARES OF                                       SHARES OF
                                                                    PIONEER                                         PIONEER
                                   AGGREGATE       AGGREGATE        COMMON                         AGGREGATE        COMMON
                                     MERGER          MERGER          STOCK           CASH            MERGER          STOCK
PARTNERSHIP NAME                     VALUE           VALUE         OFFERED(a)       PAYMENT          VALUE         OFFERED(a)
----------------                  ------------    ------------    ------------    ------------    ------------    ------------
                                                                                                
Parker & Parsley 88-C, L.P.              7,833              --          26,792         160,732         642,988           11.04
Parker & Parsley Producing
Properties 88-A, L.P.                   33,093              --          80,303         481,810       1,927,264           14.41
Parker & Parsley Private
Investment 88, L.P.                     32,842              --         135,475         812,830       3,251,380           13.60
Parker & Parsley 89-A
Conv., L.P.                              8,987              --          37,070         222,410         889,670           13.25
Parker & Parsley 89-A, L.P.             60,264              --         109,097         654,580       2,618,326           13.29
Parker & Parsley 89-B
Conv., L.P.                             23,144              --          72,427         434,559       1,738,245           11.52
Parker & Parsley 89-B, L.P.             39,272              --          79,140         474,830       1,899,350           11.51
Parker & Parsley Private
Investment 89, L.P.                     28,935              --          76,034         456,191       1,824,803           10.83
Parker & Parsley 90-A
Conv., L.P.                              8,862              --          22,890         137,329         549,349            9.76
Parker & Parsley 90-A, L.P.             50,684              --          65,215         391,285       1,565,155            9.79
Parker & Parsley 90-B
Conv., L.P.                             51,712              --         127,199         763,173       3,052,755           10.76
Parker & Parsley 90-B, L.P.            105,775              --         346,860       2,081,160       8,324,640           10.78
Parker & Parsley 90-C
Conv., L.P.                             25,338              --          74,661         447,944       1,791,842            9.95
Parker & Parsley 90-C, L.P.             35,557              --         119,880         719,265       2,877,105            9.92
Parker & Parsley Private
Investment 90, L.P.                     51,077              --         135,935         815,593       3,262,423           12.46
Parker & Parsley 90
Spraberry Private                       14,400              --          59,399         356,386       1,425,568           11.42
Development, L.P.
Parker & Parsley 91-A, L.P.             62,309              --         185,073       1,110,427       4,441,741           15.99
Parker & Parsley 91-B, L.P.             52,293              --         198,084       1,188,501       4,754,013           17.62
                                  ------------    ------------    ------------    ------------    ------------    ------------
     TOTAL                        $  6,264,687    $    196,026       4,260,303    $ 25,561,270    $102,246,724          446.30
                                  ============    ============    ============    ============    ============    ============


                                                PER $1,000 INITIAL LIMITED PARTNER INVESTMENT
                                  ----------------------------------------------------------------------------

                                                                                       AMOUNT OF INITIAL
                                                                                       INVESTMENT REPAID
                                                                                  ----------------------------
                                                                                                                     LIMITED
                                                                 DISTRIBUTIONS                                      PARTNERS'
                                                                     FROM                                           AGGREGATE
                                                                   INCEPTION                                         RESERVE
                                     CASH            MERGER         THROUGH                                           VALUE
PARTNERSHIP NAME                    PAYMENT          VALUE          3/31/01            $              %              PER BOE
----------------                  ------------    ------------   -------------    ------------    ------------     ------------
                                                                                                
Parker & Parsley 88-C, L.P.              66.26          265.04        1,010.22        1,275.26          127.53%            3.60
Parker & Parsley Producing
Properties 88-A, L.P.                    86.47          345.88        1,186.76        1,532.64          153.26%            3.67
Parker & Parsley Private
Investment 88, L.P.                      81.61          326.44        1,141.98        1,468.42          146.84%            3.73
Parker & Parsley 89-A
Conv., L.P.                              79.52          318.08        1,019.82        1,337.90          133.79%            3.79
Parker & Parsley 89-A, L.P.              79.71          318.84        1,019.88        1,338.72          133.87%            3.79
Parker & Parsley 89-B
Conv., L.P.                              69.12          276.48          885.85        1,162.33          116.23%            3.58
Parker & Parsley 89-B, L.P.              69.05          276.19          885.86        1,162.05          116.21%            3.58
Parker & Parsley Private
Investment 89, L.P.                      64.99          259.94          769.01        1,028.95          102.90%            3.70
Parker & Parsley 90-A
Conv., L.P.                              58.57          234.26          871.10        1,105.36          110.54%            3.69
Parker & Parsley 90-A, L.P.              58.72          234.87          871.16        1,106.03          110.60%            3.69
Parker & Parsley 90-B
Conv., L.P.                              64.58          258.34          692.65          950.99           95.10%            3.73
Parker & Parsley 90-B, L.P.              64.67          258.68          692.73          951.41           95.14%            3.72
Parker & Parsley 90-C
Conv., L.P.                              59.72          238.88          620.92          859.80           85.98%            3.68
Parker & Parsley 90-C, L.P.              59.54          238.17          620.93          859.10           85.91%            3.68
Parker & Parsley Private
Investment 90, L.P.                      74.76          299.03          775.28        1,074.31          107.43%            3.77
Parker & Parsley 90
Spraberry Private                        68.54          274.15          717.51          991.66           99.17%            3.27
Development, L.P.
Parker & Parsley 91-A, L.P.              95.93          383.74          800.73        1,184.47          118.45%            3.89
Parker & Parsley 91-B, L.P.             105.75          422.99          687.51        1,110.50          111.05%            4.02
                                  ------------    ------------    ------------    ------------    ------------     ------------
     TOTAL                        $   2,677.87    $  10,711.32    $  47,654.70    $  58,366.02
                                  ============    ============    ============     ============


(a)  For this preliminary document, the number of shares of Pioneer common stock
     offered is based upon an assumed average closing price of $18.00 per share
     of Pioneer common stock.



                                      -5-
   15

                              NYMEX FUTURES PRICES

     The following table shows the NYMEX futures price for oil and gas as of
March 30, 2001, which Pioneer and Pioneer USA used in the calculation of the
reserve value portion of the merger value for each partnership:



         DATE               OILS ($/Bbl)         GAS ($/Mcf)(1)
         ----               ------------        ---------------
                                          
    Apr - Dec 2001             26.17                  5.18
         2002                  24.36                  4.61
         2003                  22.83                  4.16
         2004                  22.31                  4.09
         2005                  21.97                  4.12
      Thereafter               21.97                  4.12


----------

(1)  The NYMEX price for gas is quoted in dollars per million British thermal
     units, or MMBTU. We converted those prices to dollars per thousand cubic
     feet, or Mcf.

     The reserve value portion of the merger value for each partnership was
calculated using a 13.5% discount rate.

       EXAMPLE CALCULATION OF MERGER VALUE FOR PARKER & PARSLEY 81-I, LTD.


                                                                                 
Aggregate merger value for limited partners as set forth
in Table 2 of Appendix A to this document:
     Reserve value                                                     (1)   $  552,609
     Plus working capital value                                        (2)       71,931
                                                                             ----------
     Merger value                                                      (3)   $  624,540
                                                                             ==========

Initial investment as set forth in Table 1 and Table 6
of Appendix A to this document:
     Initial investment by limited partners                                  $7,410,000
     Less initial investment by Pioneer USA                                     433,000
                                                                             ----------
     Initial investment without Pioneer USA                                  $6,977,000
                                                                             ==========

Number of per $1,000 limited partner investments:                      (4)        6,977
                                                                             ==========

Per $1,000 limited partner investment as set forth in
Table 3 of Appendix A to this document:
     Reserve value                                                           $    79.20   (1) divided by (4)
     Working capital value                                                        10.31   (2) divided by (4)
                                                                             ----------
     Merger value                                                            $    89.51   (3) divided by (4)
                                                                             ==========

Allocation between cash and Pioneer common stock before
adjustment for fractional shares:
Aggregate cash payment to limited partners                             (5)   $  156,135   (3) multiplied by 25%
Aggregate value of Pioneer common stock to limited partners
                                                                       (6)      468,405   (3) multiplied by 75%
                                                                             ----------
                                                                             $  624,540
                                                                             ==========

Aggregate number of shares of Pioneer common stock offered to
limited partners of the partnership                                            26,022.5   (6) divided by $18.00
                                                                             ==========

Aggregate number of shares of Pioneer common stock offered to
limited partners of the partnership rounded up to the nearest
whole share                                                            (7)       26,023
                                                                             ==========

Adjustment to cash for rounding up of fractional shares:
    Merger value                                                             $  624,540
    Less: Aggregate value of Pioneer common stock to limited
    partners                                                                    468,414   (7) multiplied by $18.00
                                                                             ----------
    Aggregate cash payment to limited partners                               $  156,126
                                                                             ==========

Number of shares of Pioneer common stock offered per $1,000
limited partner investment                                                         3.73   (7) divided by (4)
                                                                             ==========




                                      -6-
   16

                        BENEFITS TO THE LIMITED PARTNERS

     We believe the merger of each partnership provides the following benefits
to the limited partners of the partnership:

     Liquidity. None of the partnership interests of any of the partnerships are
traded on a national stock exchange or in any other significant market. No
liquid market exists for interests in any of the partnerships. Although some
partnership interests are occasionally sold in private or an informal secondary
market for limited partner securities, we believe the potential buyers in such
transactions are few and the prices generally reflect a significant discount for
illiquidity. See Table 15 of Appendix A for historical information about recent
trades of partnership interests in each partnership. Repurchase obligations
exist in only a few of the partnerships and are limited in both amount and price
by formula in the partnership agreements. See Table 8 of Appendix A for
repurchase information.

     The merger of each partnership provides liquidity to the limited partners
of that partnership at a price based on oil and gas reserve values, not on
limited market demand for illiquid partnership interests. All limited partners
of a participating partnership will receive Pioneer common stock and cash in
exchange for their partnership interests shortly after completion of the merger
of the partnership. Shares of Pioneer common stock are freely transferable and
listed on the New York Stock Exchange and the Toronto Stock Exchange. On April
16, 2001, the last full trading day prior to the announcement of the proposed
merger of each partnership, the last reported sales price of Pioneer common
stock, as reported by the New York Stock Exchange, was $17.27.

     Superior Oil and Gas Investment Vehicle. Pioneer's common stock provides an
oil and gas investment vehicle that is superior to the partnership interests in
each partnership because:

o    Expansion and Balancing of Reserves. The limited partners will have the
     opportunity to benefit from Pioneer's efforts (1) to expand its reserve
     base through acquisitions and development or exploratory drilling, and (2)
     to maintain a strategic balance between oil and natural gas reserves. At
     December 31, 2000, Pioneer's reserve mix was 50% oil and NGLs and 50%
     natural gas compared to the combined partnerships' reserve mix of 81% oil
     and NGLs and 19% natural gas at such date.

o    Geographic Diversification and Larger Oil and Gas Reserve Base. By
     combining each participating partnership into a single ownership entity,
     the merger of the partnership provides the limited partners of the
     partnership with an investment portfolio substantially larger and more
     geographically diversified than the portfolio of the partnership
     individually. This increased size and the resulting consolidation of
     operations spread the risk of an investment in Pioneer over a broader group
     of assets and reduces the dependence of the investment upon the performance
     of any particular asset or group of assets, such as assets in the same
     geographical area.

     Liquidation Value. The merger value for each partnership is based on the
value of the underlying properties, which we believe is essentially the same
value or a higher value than that could be achieved by selling the partnership's
property interests and liquidating the partnership at that time. In addition, we
believe that the value of Pioneer common stock and cash distributed to each
limited partner in the merger of each partnership is higher than what the
limited partners would otherwise receive over the life of the partnership,
assuming the same oil and gas commodity prices and operating costs as used to
determine the reserve value for each partnership and giving effect to the time
value of money, for the following reasons:

o    The partnership agreement for each partnership requires cash distributions
     to be reduced by general and administrative expenses allocable to the
     partnership. The merger value for each partnership reflects a liquidation
     value based on a reserve value that has not been reduced for general and
     administrative expenses.

o    The merger value for each partnership is based primarily upon the reserve
     value for the partnership, which was determined using recent NYMEX futures
     oil and gas prices that are, on average, higher than historical oil and gas
     prices. It is likely that actual oil and gas prices will vary often and
     possibly widely, as has been demonstrated historically, from the prices
     used to prepare these estimates. In that way, the merger value for each
     partnership eliminates the potential loss in value that could occur if oil
     and gas prices decline.

     Acceleration of Realization of Value. Pioneer's common stock and the cash
payment provide the limited partners of each participating partnership with
liquidity earlier than if the limited partners remain in the partnership and
receive the expected ordinary cash distributions from oil and gas production.
Because each partnership's properties are mature producing properties, we
believe that production from those properties will continue to decline at the
rate predicted in the partnership's oil and gas engineering reserve reports.
Accordingly, cash distributions from each partnership are also expected to
decline, subject to variation for changes in oil and gas prices.

     Elimination of Partnership Tax Reports. The merger of each participating
partnership will eliminate the limited partners' Schedule K-1 tax reports for
the partnership for tax years after the merger occurs. This is expected to
simplify the limited partners' individual tax return preparation and reduce
preparation costs.

                                FRACTIONAL SHARES

     Pioneer will not issue fractional shares to any limited partner upon
completion of the merger of any partnership. Instead, Pioneer will round any
fractional shares of Pioneer common stock up to the nearest whole share and will
reduce the cash payment to a



                                      -7-
   17

limited partner of a participating partnership by the amount rounded up based on
the average closing price per share used in determining the number of shares of
Pioneer common stock to be offered.

                                  RISKS FACTORS

     You should carefully consider the risks relating to the merger of each
partnership in which you own an interest described in "Risk Factors" on page 17
of this document. These include:

o    The merger value for the partnership determines the amount of Pioneer
     common stock and cash you will receive in the merger of the partnership.
     Pioneer and Pioneer USA determined each merger value and will not adjust it
     for changes in partnership value before the merger is completed.

o    You were not independently represented in establishing the terms of any
     merger.

o    Our board of directors had conflicting interests in evaluating each merger
     because each member of our board of directors is also an officer of
     Pioneer.

                       RECOMMENDATION TO LIMITED PARTNERS
                                  (SEE PAGE 28)

     On              , 2001, our board of directors unanimously determined that
the merger of each partnership in which you own an interest is advisable, fair
to you, as an unaffiliated limited partner, and in your best interests. Our
board recommends that you, as an unaffiliated limited partner, vote for the
merger proposals for each partnership in which you own an interest. Although our
board of directors has attempted to fulfill its fiduciary duties to you, our
board of directors had conflicting interests in evaluating each merger because
each member of our board of directors is also an officer of Pioneer.

                                    FAIRNESS

     In deciding to approve the merger of each partnership on            , 2001,
our board of directors decided that each merger of a partnership in which you
own an interest is advisable, fair to you, as an unaffiliated limited partner,
and in your best interests based on a variety of factors. These factors include:

o    the form and amount of consideration offered to you;

o    the comparison of the amount of Pioneer common stock offered and cash that
     will be paid in each merger to the future cash distributions otherwise
     expected as oil and gas production continues to decline and general and
     administrative expenses continue to be incurred;

o    the elimination after the merger of each participating partnership of its
     limited partners' tax preparation costs relating to partnership tax
     information;

o    the belief that the price offered by Pioneer is a competitive price because
     of:

     -    the commodity pricing used in determining the merger value for each
          partnership;

     -    Pioneer USA's position as operator of most of each partnership's
          wells; and

     -    Pioneer USA's significant ownership of nearby properties; and

o    the fairness opinion from Stanger.

                      FAIRNESS OPINION OF FINANCIAL ADVISOR
                                  (SEE PAGE 29)

     Stanger has issued a fairness opinion dated              , 2001, that,
subject to the qualifications expressed in the opinion, the merger value for
each partnership and the allocation of the merger value of the partnership (1)
to the limited partners of the partnership as a group, (2) to the general
partners of the partnership as a group, (3) to Pioneer USA as the managing or
sole general partner of the partnership, (4) to the unaffiliated limited
partners of the partnership as a group and (5) to the unaffiliated limited
partners of the nonmanaging general partner, if any, of the partnership as a
group, is fair to the unaffiliated limited partners of the partnership and the
unaffiliated limited partners of the nonmanaging general partner, if any, of the
partnership, from a financial point of view. The full text of the form of
written opinion of Stanger is attached to this document as Appendix C. You
should read all of it carefully. THE OPINION OF STANGER IS DIRECTED TO OUR BOARD
OF DIRECTORS. IT IS NOT A RECOMMENDATION TO YOU ABOUT HOW YOU SHOULD VOTE ON
MATTERS RELATING TO THE PROPOSED MERGER OF ANY PARTNERSHIP IN WHICH YOU OWN AN
INTEREST.

                          MATERIAL U.S. FEDERAL INCOME
                                TAX CONSEQUENCES
                                  (SEE PAGE 44)

     You will generally recognize gain or loss equal to the difference between
(1) the sum of the amount of cash and the value of the Pioneer common stock you
receive in the merger of each partnership in which you own interests and (2)
your adjusted tax basis in your partnership interests in that participating
partnership. Your gain or loss will be capital or ordinary depending on the
nature of the assets held by each participating partnership in which you own an
interest and the amount of depletion and intangible drilling and development
costs that must be recaptured. You must calculate your ordinary and capital gain
or loss separately for each partnership in which you own an interest.

     TAX MATTERS ARE VERY COMPLICATED. THE TAX CONSEQUENCES OF EACH MERGER OF A
PARTNERSHIP IN WHICH YOU OWN AN INTEREST TO YOU WILL DEPEND ON THE FACTS OF YOUR
OWN SITUATION. YOU SHOULD SEEK TAX ADVICE FOR A FULL UNDERSTANDING OF THE
PARTICULAR TAX CONSEQUENCES OF EACH SUCH MERGER TO YOU.

                       CERTIFICATION OF NON-FOREIGN STATUS

     YOUR CERTIFICATE THAT YOU ARE NOT A FOREIGN PERSON, WHICH WE CALL A
CERTIFICATION OF NON-FOREIGN



                                      -8-
   18

STATUS, IS IMPORTANT. Whether or not you plan to vote on the merger of each
partnership in which you own an interest, please take the time to complete and
return to us the enclosed certification of non-foreign status. If we receive a
properly completed certification of non-foreign status from you, we will not
withhold federal income taxes on the Pioneer common stock and cash to be paid to
you upon the merger of each partnership in which you own an interest.

                            RECORD DATE; VOTING POWER

     You may vote at the special meeting for each partnership in which you own
an interest if you owned partnership interests as of the close of business on ,
2001. We call this date the record date. For each partnership in which you own a
partnership interest, you may cast one vote representing your percentage of
partnership interests in that partnership. The percentage of partnership
interests that you own is determined by comparing the amount of:

o    your, or your predecessor's, initial investment, including any additional
     assessments, in the partnership; to

o    the total investment of all partners, including any additional assessments,
     in the partnership.

     YOUR VOTE IS IMPORTANT. Whether or not you plan to attend the special
meeting for each partnership in which you own an interest, please take the time
to vote by completing and mailing to us the enclosed proxy card. This will not
prevent you from revoking your proxy at any time prior to the special meeting
for each partnership in which you own an interest or from voting your
partnership interests in person if you later choose to attend the special
meeting for each partnership in which you own an interest.

                  PARTNER VOTE REQUIRED TO APPROVE THE MERGERS

     The favorable vote of the holders of a majority of the limited partnership
interests in a partnership is required to approve the merger proposals for that
partnership, except that Parker & Parsley 91-A, L.P. and Parker & Parsley 91-B,
L.P. each require the favorable vote of the holders, other than Pioneer USA, of
66 2/3% of its limited partnership interests to approve the merger proposals.

     We are generally entitled under the partnership agreements to vote
partnership interests we hold as limited partners at the special meeting for
each partnership in which we hold an interest. See "The Special Meetings --
Record Date; Voting Rights and Proxies" on page 55 of this document. We plan to
vote all our partnership interests for the merger proposals. The voting interest
that we hold in each partnership is found in Table 6 of Appendix A.

     Except as set forth above and in "Ownership of Partnership Interests" on
page 61 of this document, none of Pioneer, Pioneer USA, or, to the knowledge of
Pioneer USA, any of their directors or executive officers, or any associate or
subsidiary of Pioneer, Pioneer USA or any such director or officer beneficially
owns any partnership interests of any partnership or is otherwise entitled to
vote any partnership interests.

     If limited partners of a partnership approve the merger agreement, but do
not approve the merger amendment, or vice versa, the partnership will not be
able to merge. LIMITED PARTNERS WHO WANT THEIR PARTNERSHIP TO PARTICIPATE IN THE
MERGER SHOULD VOTE FOR EACH OF THE MERGER PROPOSALS.

                            CONDITIONS TO EACH MERGER
                                  (SEE PAGE 52)

     We will complete the merger of each partnership only if the conditions of
the merger agreement are satisfied or, if permitted, waived. These conditions
include:

o    the limited partners' adoption and approval of the merger proposals;

o    the absence of any law or court order that prohibits the merger; and

o    the absence of any lawsuit challenging the legality or any aspect of the
     merger.

     So long as the law allows us to do so, Pioneer and we may choose to
complete a merger of any partnership even though a condition has not been
satisfied if the limited partners have approved the merger proposals. Pioneer
and we may complete the merger of any one or some of the partnerships, even if
limited partners in other partnerships do not approve the merger proposals.

                   TERMINATION OF THE MERGER OF A PARTNERSHIP
                                  (SEE PAGE 53)

     Pioneer and Pioneer USA may jointly terminate the merger agreement, for any
or all of the partnerships, at any time, even after limited partner approval.
Either Pioneer or Pioneer USA may terminate the merger agreement for any or all
of the partnerships in some circumstances, including the following:

o    the limited partners of a partnership fail to approve that partnership's
     merger; or

o    if any of the other parties is in material breach of the merger agreement.

In addition, (1) Pioneer USA may terminate the merger agreement for any
partnership, if Pioneer USA determines that termination of the merger agreement
is required for its board of directors to comply with its fiduciary duties and
(2) Pioneer may abandon the proposed merger of any or all of the partnerships if
an event occurs that causes or results in a material adverse effect, among other
things, on the price of Pioneer common stock, on the market prices for oil and
gas generally or on the oil and gas industry generally.



                                      -9-
   19

                     EFFECTS OF THE MERGER OF A PARTNERSHIP
                     ON ITS LIMITED PARTNERS WHO DO NOT VOTE
                             IN FAVOR OF THE MERGER

     You will be bound by the merger of a partnership in which you own interests
if the limited partners in your partnership vote a majority, or 66 2/3% for
Parker & Parsley 91-A, L.P. and Parker & Parsley 91-B, L.P., of their
partnership interests in favor of the merger, even if you vote against the
merger. If the merger of your partnership occurs, you will be entitled to
receive only an amount of Pioneer common stock and cash based on the merger
value for your partnership interests. You will not have appraisal, dissenters'
or similar rights in connection with the merger, even if you vote against the
merger.

                      FUTURE OF A PARTNERSHIP THAT DOES NOT
                            PARTICIPATE IN THE MERGER
                                  (SEE PAGE 47)

     If your partnership does not participate in the merger of that partnership
for any reason, that partnership will remain in existence. Some reasons your
partnership might not participate in the merger are (1) that the limited
partners vote against the merger, (2) that a condition in the merger agreement
is not satisfied, or (3) that Pioneer or we exercise a termination right with
respect to the merger for that partnership.

     At about the same time that we mail certificates representing shares of
Pioneer common stock and checks to the partners of each participating
partnership in payment of the merger value for that partnership, we will mail
any cash distributions that were delayed for administrative purposes prior to
the completion of the merger of each participating partnership to the partners
of each nonparticipating partnership.

     We have not formulated an alternative business plan for any
nonparticipating partnership. The business objectives of each nonparticipating
partnership will continue as they are. We plan to continue to manage each
nonparticipating partnership and operate it in accordance with the terms of its
current partnership agreement. Each nonparticipating partnership will continue
to operate as a separate legal entity with its own assets and liabilities.
Distributions from any nonparticipating partnership are expected to continue to
decline since its production revenues are expected to continue to decline more
quickly than its production costs. Regardless of whether any nonparticipating
partnership distributes cash, limited partners must continue to include their
share of partnership income and loss in their individual tax returns.

     The board of directors of each of Pioneer and Pioneer USA will decide what,
if any, actions Pioneer or Pioneer USA, respectively, will take regarding any
nonparticipating partnership. Potential activities might include a tender offer
for partnership interests of limited partners or a proposal to acquire the
assets of, or merge with, one or more of the nonparticipating partnerships. The
proposal may be on terms similar to or different from those of the mergers
described in this document.

                                EXPENSES AND FEES

     The expenses and fees that we will incur in connection with the merger of
each partnership are expected to be approximately $1.9 million in total. Pioneer
has agreed to pay all expenses and fees of each partnership in connection with
the merger of that partnership, whether or not the merger is completed.

                               REGULATORY APPROVAL

     No federal or state regulatory requirements must be satisfied or approvals
obtained in connection with the merger of any of the partnerships as described
in this document, except (1) filing and clearing this document with the
Securities and Exchange Commission and (2) filing certificates of merger with
the Secretary of State of the State of Delaware and the Secretary of the State
of the State of Texas.

                              SIMILAR TRANSACTIONS

     During March 2001, Pioneer offered to acquire all of the direct oil and gas
interests owned by some former officers and employees of Pioneer and Pioneer USA
in properties in which Pioneer and Pioneer USA own interests. The terms of those
purchases and the method of establishing the purchase price payable to such
individuals are the same as those used to determine the reserve value portion of
the merger value for each partnership described in this document, except that
the NYMEX futures prices were as of a different date in March 2001, and the
consideration to be paid in the purchases of the direct oil and gas interests is
all cash since offering and registering Pioneer common stock in those purchases
is cost-prohibitive due to the small size of such transactions. Similarly,
during 2000, Pioneer purchased all of the direct oil and gas interests held by
Scott D. Sheffield, its chairman of the board of directors and chief executive
officer, for $0.2 million.

     Additionally, in December 2000, Pioneer received the approval of the
partners of 13 employee limited partnerships to merge with Pioneer USA for
aggregate merger consideration of $2.0 million. Of the total merger
consideration, $0.3 million was paid to current Pioneer employees. The terms of
those mergers and the method of establishing the merger values for those
partnerships were the same as those used to determine the merger value for each
partnership described in this document, except that the NYMEX futures prices
were as of August 25, 2000, and the consideration paid in those mergers was all
cash. As with the purchases of the direct oil and gas interests described above,
offering and registering Pioneer common stock in those mergers was
cost-prohibitive due to the small size of such transactions.

                               THIRD PARTY OFFERS
                                  (SEE PAGE 48)

     We will consider any offers from third parties to purchase any partnership
or its assets. Those who wish to make an offer for any partnership or its assets
must demonstrate to our reasonable satisfaction their financial ability and
willingness to complete such a



                                      -10-
   20

transaction. Before reviewing non-public information about a partnership, a
third party will need to enter into a customary confidentiality agreement.
Offers should be at prices and on terms that are fair to the partners of the
partnership and more favorable to the unaffiliated limited partners than the
prices and terms proposed in the merger for that partnership described in this
document. Pioneer has the right to match or top any such offer. Since first
announcing our willingness to consider third party offers in September 1999, we
have not received any third party offer for any partnership or its assets.

                       COMPARATIVE PER SHARE MARKET PRICE
                            INFORMATION (SEE PAGE 59)

     On April 16, 2001, the last full trading day before the public announcement
of the proposed merger of each partnership, Pioneer common stock closed at
$17.27 per share. On          , 2001, Pioneer common stock closed at $     per
share.

     No liquid market exists for interests in any of the partnerships. See Table
15 of Appendix A for historical information about recent trades per $1,000
initial limited partner investment in each partnership and Table 7 of Appendix A
for the average historical quarterly cash distributions per $1,000 initial
limited partner investment for each partnership.



                                      -11-
   21

            SUMMARY HISTORICAL CONSOLIDATED FINANCIAL DATA OF PIONEER

     The following table sets forth summary financial information of Pioneer for
the three months ended March 31, 2001 and 2000 and the five years ended December
31, 2000. This financial information was derived from the consolidated financial
statements of Pioneer. This data should be read in conjunction with the
consolidated financial statements of Pioneer and Management's Discussion and
Analysis of Financial Condition and Results of Operations contained in the
reports incorporated by reference in this document.



                                           THREE MONTHS ENDED
                                                MARCH 31,                            YEAR ENDED DECEMBER 31,
                                          ---------------------    -------------------------------------------------------------
                                            2001        2000         2000         1999         1998        1997(a)       1996
                                          ---------   ---------    ---------    ---------    ---------    ---------    ---------
                                              (UNAUDITED)
                                                                   (IN MILLIONS EXCEPT PER SHARE DATA)
                                                                                                  

STATEMENT OF OPERATIONS DATA:
  Revenues:
   Oil and gas                            $           $   174.4    $   852.7    $   644.6    $   711.5    $   536.8    $   396.9
   Natural gas processing                                    --           --           --           --           --         23.8
   Interest and other(b)                                    3.7         25.8         89.7         10.4          4.3         17.5
   Gain (loss) on disposition of
    assets, net                                             8.4         34.2        (24.2)         (.4)         4.9         97.1
                                          ---------   ---------    ---------    ---------    ---------    ---------    ---------
                                                          186.5        912.7        710.1        721.5        546.0        535.3
                                          ---------   ---------    ---------    ---------    ---------    ---------    ---------
  Costs and expenses:
   Oil and gas production                                  43.1        189.3        159.5        223.5        144.2        110.3
   Natural gas processing                                    --           --           --           --           --         12.5
   Depletion, depreciation and
    amortization                                           51.9        214.9        236.1        337.3        212.4        112.1
   Impairment of properties and
    facilities                                               --           --         17.9        459.5      1,356.4           --
   Exploration and abandonments                            13.1         87.5         66.0        121.9         77.2         23.0
   General and administrative                               9.7         33.3         40.2         73.0         48.8         28.4
   Reorganization                                            --           --          8.5         33.2           --           --
   Interest                                                39.8        162.0        170.3        164.3         77.5         46.2
   Other(c)                                                14.4         67.2         34.7         39.6          7.1          2.5
                                          ---------   ---------    ---------    ---------    ---------    ---------    ---------
                                                          172.0        754.2        733.2      1,452.3      1,923.6        335.0
                                          ---------   ---------    ---------    ---------    ---------    ---------    ---------
  Income (loss) before income taxes
   and extraordinary item                                  14.5        158.5        (23.1)      (730.8)    (1,377.6)       200.3
  Income tax benefit (provision)                             .3          6.0           .6        (15.6)       500.3        (60.1)
                                          ---------   ---------    ---------    ---------    ---------    ---------    ---------
  Income (loss) before extraordinary
   item                                                    14.8        164.5        (22.5)      (746.4)      (877.3)       140.2
  Extraordinary item                                         --        (12.3)          --           --        (13.4)          --
                                          ---------   ---------    ---------    ---------    ---------    ---------    ---------
  Net income (loss)                       $           $    14.8    $   152.2    $   (22.5)   $  (746.4)   $  (890.7)   $   140.2
                                          =========   =========    =========    =========    =========    =========    =========
  Income (loss) before extraordinary
   item per share:
    Basic                                 $           $     .15    $    1.65    $    (.22)   $   (7.46)   $  (16.88)   $    3.95
                                          =========   =========    =========    =========    =========    =========    =========
    Diluted                               $           $     .15    $    1.65    $    (.22)   $   (7.46)   $  (16.88)   $    3.47
                                          =========   =========    =========    =========    =========    =========    =========
  Net income (loss) per share:
    Basic                                 $           $     .15    $    1.53    $    (.22)   $   (7.46)   $  (17.14)   $    3.95
                                          =========   =========    =========    =========    =========    =========    =========
    Diluted                               $           $     .15    $    1.53    $    (.22)   $   (7.46)   $  (17.14)   $    3.47
                                          =========   =========    =========    =========    =========    =========    =========
  Dividends per share                     $           $      --    $      --    $      --    $     .10    $     .10    $     .10
                                          =========   =========    =========    =========    =========    =========    =========
  Weighted average basic shares
   outstanding                                            100.2         99.4        100.3        100.1         52.0         35.5

STATEMENT OF CASH FLOWS DATA:
  Cash flows from operating activities    $           $    47.2    $   430.1    $   255.2    $   314.1    $   228.2    $   230.1
  Cash flows from (used in) investing
   activities                             $           $   (39.9)   $  (194.5)   $   199.0    $  (517.0)   $  (341.2)   $    13.7
  Cash flows from (used in) financing
   activities                             $           $    (8.9)   $  (244.1)   $  (479.1)   $   190.9    $   166.0    $  (245.4)

BALANCE SHEET DATA (AS OF DECEMBER 31):
  Working capital (deficit)(d)            $           $     3.1    $   (25.1)   $   (13.7)   $  (324.8)   $    46.6    $    26.1
  Property, plant and equipment, net      $           $ 2,511.3    $ 2,515.0    $ 2,503.0    $ 3,034.1    $ 3,515.8    $ 1,040.4
  Total assets                            $           $ 2,969.9    $ 2,954.4    $ 2,929.5    $ 3,481.3    $ 4,153.0    $ 1,199.9
  Long-term obligations                   $           $ 1,913.8    $ 1,804.5    $ 1,914.5    $ 2,101.2    $ 2,124.0    $   329.0
  Preferred stock of subsidiary           $           $      --    $      --    $      --    $      --    $      --    $   188.8
  Total stockholders' equity              $           $   816.6    $   904.9    $   774.6    $   789.1    $ 1,548.8    $   530.3




                                      -12-
   22

----------

(a)  Includes amounts relating to the acquisition of MESA Inc. and Chauvco
     Resources Ltd. in August and December 1997, respectively.

(b)  1999 includes $41.8 million of option fees and liquidated damages related
     to an unsuccessful asset sale and $30.2 million of income associated with
     an excise tax refund.

(c)  The three month periods ended March 31, 2001 and 2000 and the years ended
     December 31, 2000, 1999, 1998 and 1997 include non-cash mark-to-market
     charges for changes in the fair values of non-hedge financial instruments
     of $ million, $13.5 million, $58.5 million, $27.0 million, $21.2 million
     and $5.2 million, respectively.

(d)  The 1998 working capital deficit includes $306.5 million of current
     maturities of long-term debt.




                                      -13-
   23

         SUMMARY UNAUDITED PRO FORMA COMBINED FINANCIAL DATA OF PIONEER

     The following table sets forth summary unaudited pro forma combined
financial data of Pioneer that is presented to give effect to the merger of each
of the partnerships. The information was prepared based on the following
assumptions:

     o    The merger of each partnership will be accounted for as a purchase
          business combination under generally accepted accounting principles.

     o    The income statement data is presented as if the merger of each
          partnership had been consummated on January 1, 2000.

     o    The balance sheet data is presented as if the merger of each
          partnership had been consummated on December 31, 2000.

     You should consider the following:

     o    The unaudited pro forma combined financial data are not necessarily
          indicative of the results of operations or the financial position of
          Pioneer that would have occurred had the merger of each partnership in
          which you own an interest been consummated on January 1, 2000, nor are
          they necessarily indicative of future results of operations or
          financial position of Pioneer.

     o    The unaudited pro forma combined revenue and expense data exclude the
          cost savings expected to be realized through the consolidation of
          operations of Pioneer and each partnership and the elimination of
          duplicate expenses.

     The unaudited pro forma combined financial statements should be read
together with (1) the historical consolidated financial statements of Pioneer
incorporated by reference in this document, (2) the historical financial
statements of each partnership contained in the supplement to this document for
the partnership, and (3) the unaudited pro forma combined financial statements
contained elsewhere in this document. With respect to future cash distributions,
see "Questions and Answers About the Merger of Each Partnership -- What Happens
to My Future Cash Distributions?" See also "Where You Can Find More Information"
on page 74.



                                                                                        PRO FORMA
                                                                                       YEAR ENDED
                                                                                    DECEMBER 31, 2000
                                                                                  --------------------
                                                                                  (IN THOUSANDS EXCEPT
                                                                                     PER SHARE DATA)
                                                                              
STATEMENTS OF OPERATIONS:
     Revenues:
         Oil and gas ...........................................................     $    901,382
         Interest and other ....................................................           26,231
         Gain on disposition of assets, net ....................................           34,425
                                                                                     ------------
                                                                                          962,038
     Costs and Expenses:
         Oil and gas production ................................................          202,176
         Depletion, depreciation and amortization ..............................          221,942
         Exploration and abandonments ..........................................           87,619
         General and administrative ............................................           40,406
         Interest ..............................................................          163,781
         Other .................................................................           67,231
                                                                                     ------------
                                                                                          783,155
                                                                                     ------------
     Income from continuing operations before income taxes .....................          178,883
     Income tax benefit ........................................................            6,000
                                                                                     ------------
     Income from continuing operations .........................................     $    184,883
                                                                                     ============
     Income from continuing operations per common share, basic and diluted .....     $       1.78
     Weighted average number of shares outstanding .............................          103,646
BALANCE SHEET DATA (AT PERIOD END)
     Property, plant and equipment, net ........................................     $  2,606,671
     Total assets ..............................................................     $  3,058,810
     Long-term debt ............................................................     $  1,606,319
     Stockholders' equity ......................................................     $    981,737



                                      -14-
   24

                     SUMMARY OIL AND GAS RESERVE INFORMATION

     The following table sets forth summary information on Pioneer's and the
combined partnerships' proved oil and gas reserves at December 31, 2000, and the
summary pro forma combined information of Pioneer on proved oil and gas reserves
assuming the merger of each partnership had taken place on December 31, 2000.
Pioneer's and the combined partnerships' historical and Pioneer's pro forma
combined proved oil and gas reserve information set forth below and incorporated
by reference in this document are only estimates based primarily on reports
prepared by Pioneer's engineers for Pioneer's proved reserves and independent
petroleum engineers for the combined partnerships' proved reserves as of
December 31, 2000. The reserve information as of December 31, 2000 is based on
the prices of oil and gas as of that time. The discounted future net cash flows
set forth or incorporated by reference in this document should not be considered
as the current market value of the estimated oil and gas reserves attributable
to Pioneer's, the combined partnerships' or any partnership's properties. Under
the applicable requirements of the Securities and Exchange Commission, the
estimated discounted future net cash flows from proved reserves are based on
prices and costs as of the date of the estimate, while actual future prices and
costs may be materially higher or lower. In addition, the 10% discount factor,
which is required by the Securities and Exchange Commission to be used to
calculate discounted future net cash flows for reporting purposes, is not
necessarily the most appropriate discount factor based on interest rates
periodically in effect and risks associated with Pioneer, any partnership or the
oil and gas industry in general.

        SUMMARY HISTORICAL AND PRO FORMA OIL AND GAS RESERVE INFORMATION
                              AT DECEMBER 31, 2000



                                                                         OIL AND          NATURAL         BARRELS OF
                                                                           NGLS             GAS          EQUIVALENTS
                                                                         (MMBBLS)          (BCF)            (MMBOE)
                                                                       ------------     ------------     ------------
                                                                                                
NET PROVED RESERVES (HISTORICAL):
PIONEER:
   Developed .....................................................            232.5          1,507.8            483.8
   Undeveloped ...................................................             79.8            387.7            144.4
                                                                       ------------     ------------     ------------
     Total .......................................................            312.3          1,895.5            628.2
                                                                       ============     ============     ============
COMBINED PARTNERSHIPS:
   Developed .....................................................             27.3             37.6             33.6
                                                                       ============     ============     ============

NET PROVED RESERVES (PRO FORMA COMBINED):
   Developed .....................................................            261.8          1,546.8            519.6
   Undeveloped ...................................................             79.8            387.7            144.4
                                                                       ------------     ------------     ------------
     Total .......................................................            341.6          1,934.5            664.0
                                                                       ============     ============     ============

RESERVE VALUATION INFORMATION (IN MILLIONS):
PIONEER:
   Estimated future net cash flows ...............................                                       $     10,864
   Standardized measure of discounted future net cash flows ......                                       $      5,646
COMBINED PARTNERSHIPS:
   Estimated future net cash flows ...............................                                       $        423
   Standardized measure of discounted future net cash flows(1) ...                                       $        207
PRO FORMA COMBINED:
   Estimated future net cash flows ...............................                                       $     11,267
   Standardized measure of discounted future net cash flows ......                                       $      5,838


----------

(1)  The combined partnerships do not reflect a federal income tax provision
     since the partners of each partnership include the income of the
     partnership in their respective individual federal income tax returns.




                                      -15-
   25

                           COMPARATIVE PER SHARE DATA

     The following table summarizes the per share information for Pioneer and
the per $1,000 limited partner investment for the combined partnerships on a
historical, equivalent pro forma combined and pro forma combined basis. The pro
forma information gives effect to the merger of each partnership accounted for
by Pioneer as a purchase business combination. You should read this information
together with the historical financial statements (1) included in the annual
reports on Form 10-K and other information that Pioneer has filed with the
Securities and Exchange Commission and (2) included in the supplement to this
document for each partnership. See "Where You Can Find More Information" on page
74. With respect to future cash distributions, see "Questions and Answers About
the Merger of Each Partnership -- What Happens to My Future Cash Distributions?"
and "Risk Factors -- Pioneer Might Not Declare Dividends." You should not rely
on the pro forma combined information as being indicative of the results that
would have occurred had the merger of each partnership been completed on January
1, 2000, or the future results that Pioneer will experience after the merger of
each partnership. In addition, because Pioneer has both a different legal
structure and purpose from each partnership, the information about Pioneer and
the information about the combined partnerships are not necessarily comparable.



                                                                                            YEAR ENDED
                                                                                        DECEMBER 31, 2000
                                                                                        -----------------
HISTORICAL -- PIONEER:
                                                                                     
     Income from continuing operations per share, basic and diluted .................     $       1.65
     Book value per share ...........................................................             9.19
     Cash dividends per common share ................................................             0.00
HISTORICAL -- COMBINED PARTNERSHIPS:
     Income per $1,000 limited partner investment ...................................     $      55.15
     Book value per $1,000 limited partner investment ...............................           124.45
     Cash distributions per $1,000 limited partner investment .......................            57.22
EQUIVALENT PRO FORMA COMBINED PARTNERSHIPS PER $1,000 LIMITED PARTNER INVESTMENT
ON AN EQUIVALENT PER SHARE BASIS(1):
     Income per $1,000 limited partner investment ...................................     $       5.96
     Book value per $1,000 limited partner investment ...............................            13.44
     Cash distributions per $1,000 limited partner investment .......................             6.18
PRO FORMA COMBINED -- PIONEER:
     Income from continuing operations per share, basic and diluted .................     $       1.78
     Book value per share ...........................................................             9.56
     Cash dividends per common share(2) .............................................              .26


----------

(1)  Represents the "Historical -- Combined Partnerships" amounts divided by
     9.26, which represents the weighted average number shares of Pioneer common
     stock to be received per $1000 limited partner investment. This information
     does not reflect the benefit to any limited partner of the cash portion of
     the merger value to be paid.

(2)  Pioneer's board of directors did not declare dividends to the holders of
     Pioneer common stock during 2000. The amount of dividends, if any, paid by
     Pioneer in the future will depend on business conditions, its financial
     condition and earnings, and other factors.



                                      -16-
   26

                                  RISK FACTORS

     YOU SHOULD CAREFULLY CONSIDER THE FOLLOWING RISK FACTORS IN DETERMINING
WHETHER TO VOTE TO APPROVE THE MERGER PROPOSALS FOR EACH PARTNERSHIP IN WHICH
YOU OWN INTERESTS.

             RISK FACTORS RELATING TO THE MERGER OF EACH PARTNERSHIP

THE MERGER VALUES INVOLVE ESTIMATES THAT WILL NOT BE ADJUSTED

     Proved Reserves and Future Net Revenues Are Estimates. The calculations of
each partnership's proved reserves of crude oil, natural gas liquids and natural
gas and future net revenues from those reserves included in this document are
only estimates. Actual prices, production, operating expenses and quantities of
recoverable oil and natural gas reserves may vary from those assumed in the
estimates. Any significant variance from the assumptions used could result in
the actual quantity of each partnership's reserves and future net revenues being
materially different from the estimates used in the calculation of the merger
value for that partnership.

     The Merger Value for a Partnership Will Not Be Adjusted For Changes Before
the Completion of Its Merger. The merger value for each partnership in which you
own an interest determines the amount of Pioneer common stock and cash you will
receive in the merger of that partnership. The merger value for each partnership
is equal to the sum of the present value of estimated future net revenues from
the partnership's oil and gas reserves and its net working capital, in each case
as of March 31, 2001. Although oil and gas prices have fluctuated greatly in the
recent past and may continue to do so, the merger value for a partnership will
not be adjusted as of the closing date of the merger of that partnership to
reflect any general changes in oil or gas prices, or any other matter generally
affecting the oil and gas industry, occurring after March 31, 2001 and prior to
the closing date of the merger.

THE NUMBER OF SHARES OF PIONEER COMMON STOCK THE LIMITED PARTNERS OF EACH
PARTNERSHIP WILL RECEIVE MAY DECREASE BETWEEN NOW AND THE COMPLETION OF THE
MERGER OF THE PARTNERSHIP

     The number of shares of Pioneer common stock to be issued to the limited
partners of each partnership upon the merger of the partnership will be
determined by dividing 75% of the merger value assigned to the partnership by
the value of one share of Pioneer common stock determined as described below. As
discussed above, the merger value for each partnership will not be changed
between now and the completion of the merger for the partnership. In addition,
for purposes of example in this document, a share of Pioneer common stock has
been valued at an assumed average closing price of $18.00. However, the value of
a share of Pioneer common stock will be recalculated by computing the average
closing price of the Pioneer common stock, as reported by the New York Stock
Exchange, for the ten trading days ending three business days before the date of
the special meeting for each partnership. This recalculated value, and not the
assumed closing average closing price of $18.00 per share of Pioneer common
stock used for illustration purposes in this document and on each limited
partner's voting form, will be used to determine the actual number of shares of
Pioneer common stock to be issued in the merger of each partnership. The
recalculated value may be more or less than the assumed average closing price of
$18.00 per share of Pioneer common stock. If it is more than $18.00, you will
receive fewer shares of Pioneer common stock than the illustrations in this
document show. For historical and current market prices of Pioneer common stock,
see "Comparative Per Share Market Price and Dividend Information" on page 59.

CURRENT MARKET PRICES FOR OIL AND GAS MAY BE HIGHER THAN THE MERGER VALUE FOR A
PARTNERSHIP, WHICH MAY AFFECT DELIVERABILITY OF THE FAIRNESS OPINION

     Oil and gas prices have fluctuated greatly in the recent past and may
continue to do so in the future. Pioneer calculated each merger value based on
oil and gas prices that it believes to be fair and that are supported by current
market prices. Changes in current oil and gas prices may affect the ability of
Pioneer to obtain an opinion at the time this document is mailed to the limited
partners of each partnership as to the fairness of the consideration to be
received by limited partners. If the prices used in the calculation of each
merger value significantly differ from current prices and if Pioneer does not
modify its offer, the fairness opinion provider may be unable to render its
opinion.

YOU WERE NOT INDEPENDENTLY REPRESENTED IN ESTABLISHING THE TERMS OF THE MERGER
OF EACH PARTNERSHIP

     Pioneer and Pioneer USA determined the terms of the merger of each
partnership, including the method for determining the merger value for that
partnership, and the type and allocation among the partners of the consideration
to be given in exchange for partnership interests. We did not seek
recommendations about the type of transaction or the terms or prices from any
independent underwriter, financial advisor or other securities professional
prior to accepting the consideration Pioneer offered. The only independent
representatives in the mergers were Sayles, Lidji & Werbner, A Professional
Corporation, which provided legal services to Pioneer USA's board of directors,
Robert A. Stanger & Co., Inc., which will render its fairness opinion to Pioneer
USA's board of directors, and , which will render the legal opinion required
under the partnership agreement for each partnership, other than Parker &
Parsley Producing Properties 88-A, L.P. No representative group of limited
partners



                                      -17-
   27

and no outside experts or consultants, such as investment bankers, legal
counsel, accountants or financial experts, were engaged solely to represent the
independent interests of the limited partners of any partnership in structuring
and negotiating the terms of the merger for the partnership. If you had been
separately represented, the terms of the merger for a partnership in which you
own interests might have been different and possibly more favorable to you.

THE INTERESTS OF PIONEER, PIONEER USA AND THEIR DIRECTORS AND OFFICERS MAY
DIFFER FROM YOUR INTERESTS

     The interests of Pioneer, Pioneer USA, and their directors and officers may
differ from your interests as a result of the relationships among them. For
example, Pioneer USA, as general or managing partner of each partnership, has a
duty to manage the partnership in the best interests of the limited partners.
Additionally, Pioneer USA has a duty to operate its business for the benefit of
its sole stockholder, Pioneer. Also, the members of Pioneer USA's board of
directors have duties to both the limited partners of each partnership and to
Pioneer. All of the members of Pioneer USA's board of directors are officers of
Pioneer and have duties to Pioneer's stockholders. Pioneer USA's board of
directors was aware of these interests and considered them in approving the
merger proposals for each partnership. See "Interests of Pioneer, Pioneer USA
and Their Directors and Officers" on page 60 of this document.

PIONEER USA HAS PREVIOUSLY OFFERED EACH PARTNERSHIP FOR SALE TO OTHERS, BUT IT
DID NOT RECEIVE ANY FORMAL BIDS

     In September 1999, we first announced our willingness to consider third
party offers to purchase any partnership or its assets at prices that are higher
than the 1999 merger value for the partnership, but subject to our right to
continue operation of the properties. We believe this limited form of auction
would result in a better price to the limited partners of each partnership than
if we merely offered the partnership or its assets for sale at any price. Since
that time, we have not received any third party offer for any partnership or its
assets. As a result, we cannot be sure what the market demand is for any
partnership or its assets, individually or as a whole with the other
partnerships, or what a third party would offer for any partnership. Also,
although we do not have any plans to sell or relinquish our operating rights in
any third party sale, we cannot be sure what the market demand is for any
partnership or its assets if we also sold or relinquished our operating rights.
No assurance may be given that the terms of the merger of each partnership are
as favorable as could be obtained from a sale of any partnership or its assets,
individually or as a whole with the other partnerships, to an unrelated party.

POTENTIAL LITIGATION CHALLENGING THE MERGER OF A PARTNERSHIP MAY DELAY OR BLOCK
THE MERGER

     One or more of the partners opposed to the merger of a partnership in which
such partner or partners own an interest may initiate legal action to stop the
merger of the partnership or to seek damages for alleged violations of federal
and state laws. Litigation challenging the merger of any partnership may delay
or block the closing of the merger for one or more of the partnerships. In
addition, if any lawsuits are filed, Pioneer or Pioneer USA may decide to
terminate one or more of the mergers.

REPURCHASE RIGHTS TERMINATE ON COMPLETION OF THE MERGERS

     The limited partners of each of the partnerships listed below may require
us to repurchase their partnership interests for cash at the times and under the
conditions described in the partnership agreements for the partnership:

         Parker & Parsley 82-I, Ltd.
         Parker & Parsley 82-II, Ltd.
         Parker & Parsley 82-III, Ltd.
         Parker & Parsley 83-A, Ltd.
         Parker & Parsley 83-B, Ltd.
         Parker & Parsley 84-A, Ltd.

     The repurchase rights may be exercised only once a year. A limited partner
may exercise its repurchase right by delivering a written request to us no later
than March 31 of each year. On or before May 31 of each year, we must notify
each limited partner who has exercised its repurchase right of the amount of
limited partnership interests to be repurchased and the method of calculating
the repurchase price. The aggregate amount of limited partnership interests
required to be repurchased in any one year is limited to $100,000 per
partnership. A repurchase price is calculated by multiplying:

     o    the present value of the estimated future net revenues, calculated
          using a discount rate equal to prime plus 1% as of December 31 of each
          year, from a partnership's proved reserves, as determined by
          independent petroleum consultants; by

     o    66 2/3%.

Each limited partner who has exercised its repurchase right has 60 days to
accept our repurchase offer. We must pay the repurchase price to each limited
partner who accepts the repurchase offer within 30 days after acceptance.



                                      -18-
   28

     If the limited partners of a partnership with repurchase rights vote a
majority of their partnership interests in favor of the merger of the
partnership, those repurchase rights will terminate on completion of the merger.
As a result, if the oil and gas prices used in calculating the repurchase prices
in the future were high enough to offset the additional 33 1/3% discount factor
used in the repurchase calculation, the limited partners would not have the
opportunity to require Pioneer USA to repurchase the limited partners'
partnership interests for a price higher than the merger value for the
partnership.

     The 2001 repurchase offers will be commenced and completed before the date
of this document. In each of the partnerships with a repurchase obligation, the
repurchase price in 2001 is higher than the price being offered in the merger of
the partnership. For a list of the repurchase prices in 2001 and the prior two
years, see Table 8 of Appendix A.

YOU COULD BE BOUND BY THE MERGER OF EACH PARTNERSHIP IN WHICH YOU OWN AN
INTEREST EVEN IF YOU DO NOT VOTE IN FAVOR OF THE MERGER.

     You will be bound by the merger of each partnership in which you own an
interest if the limited partners in the partnership vote a majority, or 66 2/3%
for Parker & Parsley 91-A, L.P. and Parker & Parsley 91-B, L.P., of their
partnership interests in favor of the merger, even if you vote against the
merger or do not vote. If the merger of the partnership occurs, you will be
entitled to receive only an amount of cash and Pioneer common stock based on the
merger value of your partnership interests in the partnership. Under the laws of
the State of Delaware and the State of Texas, which are the states of formation
of the partnerships, you are not entitled to appraisal or dissenters' rights
with respect to the merger of any partnership.

                 RISKS ASSOCIATED WITH AN INVESTMENT IN PIONEER

LIMITED PARTNERS WHO BECOME PIONEER STOCKHOLDERS WILL FUNDAMENTALLY CHANGE THE
NATURE OF THEIR INVESTMENT

     Limited partners of a participating partnership will become stockholders of
Pioneer and will fundamentally change the nature of their investment. Each
partnership was generally formed as finite-life investment, with partners to
receive regular cash distributions out of the partnership's net operating income
and special distributions upon liquidation of the partnership's oil and gas
assets. In contrast, Pioneer intends to operate for an indefinite period of time
and has no specific plans for the sale of its investments. Because Pioneer will
spend a portion of its cash flow on acquisitions, drilling and other activities,
the activities of Pioneer may involve higher levels of risk than those
associated with the present or future operations of each partnership. Instead of
having their investments liquidated through the liquidation of Pioneer's assets,
stockholders should expect to be able to liquidate their investment in Pioneer
only through the sale of their investments in the market. The amount realized
through the sale of shares of Pioneer common stock may not be equal to the
amount that would have been realized by stockholders through the sale of
Pioneer's assets. Stockholders will thus be subject to the market risks of all
public companies, particularly in that the value of their equity securities may
fluctuate from time to time depending upon general market conditions, conditions
in the oil and gas industry, and Pioneer's future performance.

PIONEER MIGHT NOT DECLARE DIVIDENDS

     Limited partners of a participating partnership will become stockholders of
Pioneer and will not receive cash distributions or will receive distributions
much smaller than the distributions received from the partnership. Pioneer's
board of directors did not declare dividends to its stockholders during 1999 and
2000. The determination of the amount of future cash dividends, if any, to be
declared and paid is in the sole discretion of Pioneer's board of directors and
will depend on the following factors:

     o    Pioneer's financial condition;

     o    earnings and funds from operations;

     o    the level of Pioneer's capital and exploration expenditures;

     o    dividend restrictions in Pioneer's financing agreements;

     o    Pioneer's future business prospects; and

     o    other matters that Pioneer's board of directors deems relevant.



                                      -19-
   29

LIMITED PARTNERS WHO BECOME PIONEER STOCKHOLDERS MAY BE DILUTED

     If all partnerships participate in the mergers, the shares of Pioneer
common stock to be issued will represent approximately 4.3% of the shares of
Pioneer common stock outstanding on the date of this document. Because of the
increased liquidity afforded to the limited partners of each partnership after
the merger of the partnership, all of those shares of Pioneer common stock may
be offered for sale in a relatively short period of time, which could result in
the price at which shares of Pioneer common stock trade after completion of the
merger of each partnership being less than the price at which such shares traded
immediately prior to the completion of the merger of each partnership. In
addition, limited partners of a partnership who become Pioneer stockholders will
be subject to the risk that their equity interests in Pioneer may be diluted
through the issuance of additional equity securities. Pioneer has the right to
issue, at the discretion of its board of directors, shares other than those to
be issued in the merger of each partnership, upon such terms and conditions and
at such prices as its board of directors may establish. In addition, Pioneer may
in the future issue preferred stock that might have priority over the Pioneer
common stock as to distributions and liquidation proceeds.

DIVIDENDS PAID TO PIONEER STOCKHOLDERS ARE TAXED AT TWO LEVELS

     Pioneer is taxed on its income, after deduction of expenses, at both the
federal and state levels. Pioneer stockholders, including limited partners who
become Pioneer stockholders, are separately taxed on the receipt, if any, of
dividends.

PIONEER'S BUSINESS ACTIVITIES INVOLVE RISKS

     The nature of the business activities conducted by Pioneer subjects it to
hazards and risks. In evaluating an investment in shares of Pioneer common
stock, prospective investors should consider carefully, among other things, the
risk factors set forth in "Item 1. Business -- Risks Associated with Business
Activities" contained in Pioneer's annual report on Form 10-K for the year ended
December 31, 2000 (File No. 1-13245) that Pioneer filed with the SEC on February
27, 2001.




                                      -20-
   30

                                 SPECIAL FACTORS

BACKGROUND OF THE MERGER OF EACH PARTNERSHIP

     The partnerships were formed from 1981 through 1991 under the sponsorship
of various affiliated companies collectively known as Parker & Parsley. On
February 19, 1991, Parker & Parsley's principal company converted from limited
partnership form to corporate form and acquired most of the assets of five oil
and gas limited partnerships. The new corporation was called Parker & Parsley
Petroleum Company, and it owned the sole or managing general partners of the
partnerships.

     In early 1992, Parker & Parsley Petroleum Company decided that it could not
fully realize the benefits of the properties it had acquired while continuing to
devote substantial resources to the sponsorship of and drilling for each
partnership. It stopped sponsoring oil and gas development drilling and income
partnerships and focused on its corporate development. In 1997, Parker & Parsley
Petroleum Company and MESA Inc. combined their businesses in a merger that
created Pioneer Natural Resources Company. That same year, Pioneer combined many
of its U.S. subsidiaries, including the managing or sole general partner of each
of the partnerships, into its main subsidiary, Pioneer USA.

     From time to time since 1992, Pioneer and its predecessors have had
general, internal discussions about whether to consolidate each partnership
pursuant to a transaction such as the merger of each partnership. On several
occasions, Pioneer or its predecessors engaged outside legal counsel and had
discussions with investment banks about a possible combination with each of the
partnerships. Some of those discussions were with Stanger. The contemplated
structure of the combination has varied significantly during these internal
discussions and has included issuances of common stock, combinations of common
stock and cash, and cash-only transactions through asset sales, mergers, tender
offers, and combinations of those types of transactions. In general, the
contemplated transactions would have been taxable to the limited partners of
each partnership because of the difficulties involved in structuring a tax-free
transaction for the partnership. Until 1999, every time Pioneer or its
predecessors considered such a transaction, it decided not to complete the
transaction. The reasons Pioneer and its predecessors did not previously
complete a transaction varied. In some early cases, they wanted to collect and
fully distribute proceeds to the limited partners of each partnership from
litigation against an oilfield services company before trying to value any
partnership. In other cases, they wanted to avoid periods of volatility in oil
and gas prices or in Pioneer's stock price. On several occasions, Pioneer was
involved in other corporate transactions that could not be completed timely if a
transaction with each partnership was also pending.

     In early 1998, Pioneer was formulating a strategic plan to focus on its 25
core area oil and gas fields and to eliminate ancillary operations. Pioneer
began discussions internally to consider a transaction involving each
partnership, including the basis for valuing each partnership and whether the
consideration should be Pioneer common stock, cash or some combination of both.

     During the second quarter of 1998, Pioneer and Pioneer USA began to discuss
the methods for valuing each partnership. At that time, the board of directors
of Pioneer USA engaged Sayles, Lidji & Werbner, A Professional Corporation (then
known as Sayles & Lidji, A Professional Corporation) based in Dallas, Texas, as
its independent legal counsel to assist the board in evaluating a potential
transaction with Pioneer. Pioneer USA's board also engaged Stanger as its
financial advisor to review any proposed transaction and to render an opinion as
to the fairness of the offer price, from a financial point of view, to the
unaffiliated limited partners of each partnership. In May 1998, Pioneer
submitted an offer to merge each partnership into Pioneer USA using Pioneer
common stock or a combination of Pioneer common stock and cash. The pricing for
that offer was primarily based on oil and gas prices and the present value of
estimated future net revenues from each partnership's oil and gas reserves, in
each case as of December 31, 1997. The present value of estimated future net
revenues was determined in accordance with the SEC's reporting convention that
provides a common basis for comparing oil and gas companies and requires the use
of oil and gas prices as of the date of computation, but using a 15% discount
rate. After some negotiation with Pioneer USA, Pioneer withdrew the May 1998
offer due to the decline in oil prices. In July 1998, Pioneer submitted a second
offer using Pioneer common stock, or at its option upon the occurrence of
specified events, a combination of Pioneer common stock and cash. The oil and
gas pricing for the second offer was lower than the pricing in the May 1998
offer due to the continued decline in oil prices, but the discount rate for the
second offer was the same as the May 1998 offer. Pioneer and Pioneer USA decided
to discontinue further discussions and not to submit the proposed transaction to
the limited partners of any partnership because of:

     o    the continued decline in oil prices, which in turn would reduce any
          merger value to be paid to the limited partners of each partnership;

     o    the decline in Pioneer's stock price; and

     o    the tight lending environment for many oil and gas companies,
          including Pioneer.



                                      -21-
   31

     As oil and gas prices improved, in June 1999, Pioneer and Pioneer USA again
began discussions internally to consider a transaction involving each
partnership. At that time, Scott Sheffield, the President and Chief Executive
Officer of Pioneer, contacted members of Pioneer USA's board regarding
consideration of a potential transaction involving each partnership. Pioneer did
not submit a written offer to Pioneer USA at that time.

     During the second quarter of 1999, Pioneer and Pioneer USA attempted to
formally address the conflicting interests inherent in the relationships among
Pioneer, Pioneer USA, each partnership and the officers and directors of Pioneer
and Pioneer USA. Pioneer USA caused Scott D. Sheffield to resign from Pioneer
USA's board of directors because he is also a member of Pioneer's board of
directors. He was not replaced. Pioneer USA did not consider replacing Mr.
Sheffield with an unaffiliated director because Pioneer USA is a 100% subsidiary
of Pioneer and typically such wholly-owned subsidiaries do not have unaffiliated
directors. Because all of the board members of Pioneer USA are also employees of
Pioneer, an inherent conflict exists with respect to their duties to the limited
partners of each partnership in their capacity as directors of Pioneer USA, on
the one hand, and their duties to Pioneer as employees, on the other hand. This
separation of board processes may lessen, but does not eliminate, the inherent
conflicting interests of the Pioneer USA directors in this transaction. We
believe, however, that this separation enables our directors to consider and
focus on the interests of each partnership more effectively.

     Shortly thereafter, Pioneer USA's board again engaged Sayles, Lidji &
Werbner to advise the board in connection with a proposed transaction with
Pioneer and any other alternative transaction that the board determined was
worth consideration.

     Pioneer USA's board also engaged, on behalf of each partnership, Stanger,
as its financial advisor to advise the board on the fairness from a financial
point of view of the merger value for each partnership to be paid to the
unaffiliated limited partners in the partnership for the limited partnership
interests in the partnership and to assist in Pioneer USA's evaluation of the
merger transaction and other strategic alternatives. Stanger was familiar with
the circumstances from its 1998 engagement.

     On July 14, 1999, Pioneer USA's board met with its counsel and Stanger to
discuss the proposed merger of each partnership. Stanger presented an overview
of the analysis it planned to perform in evaluating the fairness of the proposed
transaction. Stanger advised Pioneer USA's board that Stanger would review the
following for each partnership:

     o    the reserve report to be prepared by Williamson Petroleum Consultants,
          Inc. as of September 30, 1999;

     o    the most recent quarterly financial statements;

     o    the estimated cash distributions;

     o    the estimated net asset value, going concern value and liquidation
          value;

     o    secondary market prices;

     o    tender offers; and

     o    repurchase offers.

Sayles, Lidji & Werbner then reviewed and discussed with the board the
procedures that would be involved in completing the proposed transaction with
Pioneer. The discussion topics included:

     o    the process in which Pioneer USA's board of directors would approve
          the proposed transaction;

     o    the submission of the proposed merger of each partnership to the
          limited partners of the partnership for approval;

     o    the evaluation of offers from third parties;

     o    the application of and compliance with the requirements of the federal
          securities laws; and

     o    the timing of the proposed transaction.

     Members of the Pioneer USA board met informally on several occasions during
July and early August to discuss among each other the proposed terms of the
merger transaction and other potential alternative transactions, including the
formation of a royalty trust or a master limited partnership.

     On August 16, 1999, at a special meeting of the Pioneer USA board, the
board met with representatives of Sayles, Lidji & Werbner and Stanger to discuss
the proposed merger of each partnership into Pioneer USA. Pioneer USA's board
discussed with the representatives of Stanger and Sayles, Lidji & Werbner the
proposed terms of the offer expected from Pioneer, including the expected
pricing parameters of $18 per Bbl of oil and $2.40 per Mcf of gas and the
expected timing of receipt of Pioneer's formal written offer. Stanger discussed
the progress it was making on its financial analysis of each partnership and its
determination of the fairness from a financial point of view of the merger value
for each partnership to be paid in cash for the limited partners' interests in
the partnership. Stanger's discussion centered on (1) the price to be paid for
the oil and gas reserves, (2) the discount rate, (3) the application of overhead
charges and administrative charges, and (4) the responsibility for any
transaction expenses. Following this discussion, the board and its counsel
discussed the board's fiduciary duties in evaluating the proposed transaction
with Pioneer and the making of a recommendation to the unaffiliated limited
partners. Finally, the board decided to request that Pioneer make a formal
written offer outlining the terms of the proposed merger transaction.



                                      -22-
   32

     On August 17, 1999, in response to Pioneer USA's request for a written
offer, Pioneer delivered to Pioneer USA's board a written proposal which
outlined the terms of the proposed merger transaction. The written offer
specified that the pricing for the oil and gas reserves would be based on 95% of
the arithmetic average of a four-year or five-year NYMEX futures price. The
future cash flows generated by this pricing structure would then be discounted
using a 15% discount rate. At a special meeting that day of Pioneer USA's board,
the board, its counsel and Stanger met to discuss the specifics of Pioneer's
offer, including oil and gas pricing, the present value discount rate, the right
to allow others to bid on the property, and the costs of the merger of each
partnership. Following the board meeting, Pioneer USA's directors determined
that it would be advantageous to each partnership to seek more favorable pricing
terms and a lower discount rate. Thus, the board decided to continue discussions
of the written offer.

     On August 23, 1999, at a special meeting of Pioneer USA's board, the board
updated its counsel and Stanger on the status of its discussions with Pioneer.
As a result of continued discussions, Pioneer and Pioneer USA agreed, in
response to requests by Stanger, (1) to reduce the discount rate from 15% to
12.5%, (2) to increase the pricing of the oil reserves from 95% of the
arithmetic average of a four-year or five-year NYMEX futures price to 100% of
the arithmetic average of the five-year NYMEX futures price, (3) to a fixed
price of $2.40 per Mcf of gas instead of a floating NYMEX futures price and (4)
to allocate the merger expenses and fees to each participating partnership.

     On September 2, 1999, at a special meeting of Pioneer USA's board, the
board and representatives of Stanger and Sayles, Lidji & Werbner reviewed the
terms of a revised proposal submitted by Pioneer which incorporated these
changes. The parties discussed the revised terms of the merger of each
partnership and the strategic rationale for and benefits of the merger of each
partnership. At this meeting, Stanger reviewed with the board its financial
analysis and its evaluation of the merger consideration and the feasibility of
other strategic alternatives. Stanger also orally presented to the board the
status of its findings and its preliminary evaluation of the proposed
transaction.

     After considering Stanger's evaluation of the proposed merger transaction,
Pioneer USA's board, together with representatives of Stanger, engaged in a
general discussion of other possible transactions it had considered over the
last six to eight months. This discussion included anticipated ongoing
operations of each partnership under its current structure and the operation of
each partnership through a master limited partnership structure, as well as
through a royalty trust. The board discussed selling the oil and gas properties
of each partnership at auction and potentially soliciting other buyers or merger
partners. The board also considered the fact that other potential buyers of each
partnership would have an opportunity to make an offer for each partnership
before the board submitted the merger transaction to the limited partners of
each partnership for their consideration and approval.

     At a special meeting held on September 8, 1999, Pioneer USA's board
continued discussions with Sayles, Lidji & Werbner and Stanger regarding the
merger proposals for each partnership. After considering the alternatives
discussed in the preceding paragraph, including the advantages and disadvantages
of each, the board concluded that none of the alternatives was more advantageous
to the limited partners of any partnership than the terms of the proposed merger
of the partnership. The board then unanimously approved proceeding with the
merger of each partnership, subject to determination of September 30, 1999
pricing, its receipt of Stanger's fairness opinion, and the board's
determination that the merger consideration of each partnership is fair to the
unaffiliated limited partners of that partnership based on all circumstances as
of September 30, 1999, including without limitation, the then current market
conditions and the existence, if any, of any other proposal for the partnership
on terms more favorable to the limited partners.

     On September 8, 1999, in connection with the proposed merger transaction,
Pioneer and Pioneer USA filed a preliminary proxy statement and preliminary
Schedule 13e-3s with the Securities and Exchange Commission. In addition,
Pioneer and Pioneer USA publicly announced the proposed merger of each
partnership. In that announcement, Pioneer USA also announced that it would
consider proposals from other potential buyers of one or more of the
partnerships.

     On or about October 19, 1999, Pioneer submitted a verbal offer to Pioneer
USA to revise the oil reserve component of the pricing used in the preliminary
proxy statement to $18.35 per Bbl of oil. On or about November 3, 1999, Pioneer
submitted a second verbal offer to Pioneer USA to further revise the oil reserve
pricing to $18.40 per Bbl of oil. Later that month, due to the increase in oil
and gas prices over the previous several months and in response to a request
from Pioneer USA, Pioneer proposed to Pioneer USA that the merger value
calculation for each partnership be further modified (1) to increase the pricing
to $18.90 per Bbl for oil and $2.55 per Mcf of gas and (2) to increase the
discount rate to 15%.

     On November 17, 1999, in connection with the approval of Pioneer's capital
budget for 2000, Pioneer's board of directors met and voted to approve the
merger of each partnership and to proceed with the completion of each merger,
subject to the pricing information and other relevant conditions at the time.

     At a special board meeting held on November 22, 1999, Pioneer USA's board
of directors met with representatives from Stanger and Sayles, Lidji & Werbner
to discuss Pioneer's proposed pricing. Pioneer USA's



                                      -23-
   33
board agreed that an increase in the merger value for each partnership based on
Pioneer's proposed pricing was warranted to more closely reflect the current oil
and gas prices. Similarly, in view of increases in interest rates during the
months since the original proposal was made and in view of the volatility of oil
and gas prices over the previous year, Pioneer USA's board agreed to increase
the discount rate used to determine the merger value for each partnership from
12.5% to 15%. Pioneer USA's board reported that management had worked to reduce
the expected merger expenses and fees from an estimated $4.6 million to an
estimated $1.8 million, thereby increasing the merger value for each partnership
to be received by the limited partners of the partnership. The board also
received a status report on whether or not any third party offers had been
received since September 8, 1999, the date on which Pioneer and Pioneer USA
announced that it would consider such offers. In that regard, Pioneer and
Pioneer USA had not received any formal offers, but did receive a few inquiries
from third parties expressing an interest in possibly making a bid on one or
more of the partnerships or the assets of one or more of the partnerships. None
of the third parties who made inquiries have pursued the matter further. The
board then voted to extend the period it would be willing to consider third
party offers from November 1, 1999 to December 31, 1999. Stanger then reviewed
for the board Stanger's analysis of the fairness of the merger transaction using
the new terms agreed to by Pioneer and Pioneer USA. Stanger expressed its
preliminary view that the revised merger value for each partnership to be paid
in cash for the limited partnership interests in each partnership would be fair
from a financial point of view to the unaffiliated limited partners of the
partnership under recent market conditions, but stated that whether or not the
transaction would be considered fair by Stanger at the time its fairness opinion
was sought would depend on market conditions at that time. Following this
discussion, the board approved proceeding with the merger of each partnership on
the new terms, subject to (1) its receipt of a fairness opinion from Stanger,
and (2) its determination that the merger value to be paid in cash for the
limited partnership interests in each partnership is fair to the unaffiliated
limited partners of the partnership based on all circumstances, including
without limitation, the then current market conditions and the existence, if
any, of any other proposal for such partnership or its assets on terms more
favorable to the unaffiliated limited partners than the proposed merger
transaction.

     In December 1999, Pioneer became involved in another corporate transaction
which could not be completed timely without its management's dedicated time and
attention. Meanwhile, during December 1999 and the first quarter of 2000, oil
and gas prices continued to increase. As a result, during the first quarter of
2000, Pioneer and Pioneer USA began to discuss revising the pricing terms of the
proposed merger transaction to (1) an arithmetic average of the five-year NYMEX
futures price for oil and for gas and (2) a 15% discount rate. Pioneer also
proposed to offer Pioneer common stock instead of cash to the limited partners
of each participating partnership. In April 2000, Pioneer and Pioneer USA
discontinued these discussions and did not submit the proposed merger
transaction to the limited partners of any partnership because of:

          o    the decline in Pioneer's stock price;

          o    the increase in interest rates; and

          o    Pioneer's involvement in replacing existing debt with new
               publicly-held debt and a new credit facility.

     In September 2000, Pioneer and Pioneer USA began internal discussions to
consider a merger transaction involving 13 privately-held employee limited
partnerships. Pioneer offered to pay an amount of cash to the limited partners
of each participating partnership equal to the sum of the present value of
estimated future net revenues from the partnership's oil and gas reserves and
its net working capital, in each case as of September 30, 2000, less the cash
distributions on October 15, 2000 and November 15, 2000, by the partnership to
its partners. Pioneer and Pioneer USA calculated the present value of the
estimated future net revenues from each partnership's oil and gas reserves using
(1) a five-year NYMEX futures price for oil and gas as of August 25, 2000, with
prices held constant after year five at the year five price, less standard
industry adjustments, (2) historical operating costs adjusted only for those
items affected by commodity prices, such as production taxes and ad valorem
taxes, and (3) a 13.5% discount rate. Pioneer also agreed to bear the merger
expenses and fees. In December 2000, Pioneer and Pioneer USA completed the
merger of each of the 13 privately-held employee limited partnerships with and
into Pioneer USA.

     In October 2000, Pioneer terminated the preliminary proxy statement and
preliminary Schedule 13e-3s filed with the Securities and Exchange Commission on
September 8, 1999 in connection with the proposed merger transaction.

     As oil and gas prices continued to improve, in January 2001, Pioneer and
Pioneer USA renewed their internal discussions to consider a transaction
involving each of the partnerships described in this document. Pioneer offered a
combination of its common stock and cash. Pioneer and Pioneer USA agreed on a
merger value for each participating partnership equal to the sum of the present
value of estimated future net revenues from the partnership's oil and gas
reserves and its net working capital, in each case as of March 31, 2001. Pioneer
and Pioneer USA agreed to calculate the present value of the estimated future
net revenues from each partnership's oil and gas reserves using (1) a five-year
NYMEX futures price for oil and gas as of March 30, 2001, with prices held
constant after year five at the year five price, less standard industry
adjustments, (2) historical operating costs adjusted only for those items
affected by commodity prices, such as production taxes and ad valorem taxes, and
(3) a 13.5% discount rate. For 2001, the oil and gas prices would be based on
the average NYMEX futures price for the nine-


                                      -24-
   34

month period beginning on April 1, 2001 and ending December 31, 2001. Pioneer
also agreed to bear the merger expenses and fees.

     On February 15, 2001, Pioneer's board of directors met and voted to approve
the merger of each partnership, the issuance of Pioneer common stock and the
payment of cash upon each such merger, and to otherwise proceed with the
completion of each merger, subject to the pricing information and other relevant
conditions at the time.

     During March 2001, Pioneer offered to acquire all of the direct oil and gas
interests owned by some former officers and employees of Pioneer and Pioneer USA
in properties in which Pioneer and Pioneer USA own interests. The terms of those
purchases and the method of establishing the purchase price payable to such
individuals are the same as those used to determine the reserve value portion of
the merger value for each partnership described in this document, except that
the NYMEX futures prices were as of a different date in March 2001, and the
consideration to be paid in the purchases of the direct oil and gas interests is
all cash since offering and registering Pioneer common stock in those purchases
is cost-prohibitive due to the small size of such transactions. Similarly,
during 2000, Pioneer purchased all of the direct oil and gas interests held by
Scott D. Sheffield, its chairman of the board of directors and chief executive
officer, for $0.2 million.

     In April 2001, Pioneer USA contacted Sayles, Lidji & Werbner and Stanger to
advise them of the proposed merger transaction, pricing terms and merger
consideration.

     On April 9, 2001, Pioneer USA's board met with Sayles, Lidji & Werbner to
discuss the proposed merger of each partnership into Pioneer USA. The board
members reviewed the terms of the merger transaction, including the pricing
terms, the merger consideration and the terms and conditions of the proposed
merger agreement. The board members also discussed the engagement of special
legal counsel to render the legal opinion required by each partnership's
partnership agreement. Finally, Pioneer USA's board discussed the fairness
opinion to be delivered by Stanger and decided to hold another board meeting at
which Stanger would present in detail its methodology in determining that the
merger value for each partnership and the allocation of the merger value of the
partnership (1) to the limited partners of the partnership as a group, (2) to
the general partners of the partnership as a group, (3) to Pioneer USA as the
managing or sole general partner of the partnership, (4) to the unaffiliated
limited partners of the partnership as a group and (5) to the unaffiliated
limited partners of the nonmanaging general partner, if any, of the partnership
as a group, is fair to the unaffiliated limited partners of the partnership and
the unaffiliated limited partners of the nonmanaging general partner, if any, of
the partnership, from a financial point of view. The board decided to proceed
with the merger transaction, but would withhold recommending the merger
transaction to the limited partners or executing the merger agreement until it
received the fairness opinion from Stanger and determined that the merger of
each partnership is advisable, fair to the unaffiliated limited partners and in
the unaffiliated limited partners' best interests

     On April   , 2001, in connection with the proposed merger transaction,
Pioneer and Pioneer USA filed a registration statement on Form S-4 and
preliminary Schedule 13e-3s with the Securities and Exchange Commission. In
addition, Pioneer and Pioneer USA publicly announced the proposed merger of each
partnership. In that announcement, Pioneer USA also announced that it would
continue to consider proposals from other potential buyers of any partnership or
its assets.

     At a special meeting held on April   , 2001, Pioneer USA's board continued
discussions with Sayles, Lidji & Werbner and Stanger regarding the merger
proposals for each partnership. Stanger also orally presented to the board the
status of its findings and its preliminary evaluation of the proposed
transaction. The board then unanimously approved proceeding with the merger of
each partnership, subject to (1) the execution of a definitive merger agreement,
(2) its receipt of Stanger's fairness opinion, and (3) clearing this document
with the Securities and Exchange Commission for mailing to the limited partners
of each partnership.

     In a special meeting of the board of Pioneer USA held on    , 2001, Stanger
presented its opinion dated            , 2001, that the merger value for each
partnership and the allocation of the merger value of the partnership (1) to the
limited partners of the partnership as a group, (2) to the general partners of
the partnership as a group, (3) to Pioneer USA as the managing or sole general
partner of the partnership, (4) to the unaffiliated limited partners of the
partnership as a group and (5) to the unaffiliated limited partners of the
nonmanaging general partner, if any, of the partnership as a group, is fair to
the unaffiliated limited partners of the partnership and the unaffiliated
limited partners of the nonmanaging general partner, if any, of the partnership,
from a financial point of view. The board of Pioneer USA then unanimously
determined that the merger proposals for each partnership are advisable, fair to
the unaffiliated limited partners and in the unaffiliated limited partners' best
interests. Accordingly, the board recommended that the unaffiliated limited
partners of each partnership vote for the merger proposals. References to
Pioneer USA's board's recommendation of the merger of each partnership and its
finding that the merger consideration is fair from a financial point of view are
stated in this preliminary document conditioned on (1) the execution of a
definitive merger agreement, (2) its receipt of Stanger's fairness opinion, and
(3) clearing this document with the Securities and Exchange Commission for
mailing to the limited partners of each partnership.



                                      -25-
   35

REASONS FOR THE MERGER OF EACH PARTNERSHIP

     General. For all of the reasons listed below, Pioneer believes that it is
the party in the position to pay the highest price for the limited partnership
interests of each partnership. Pioneer USA also believes that Pioneer is the
most likely buyer for each partnership's properties in light of:

     o    Pioneer USA's operation of most of the properties;

     o    Pioneer USA's extensive property holdings in the same fields; and

     o    Pioneer's ability to achieve efficiencies by consolidating operations
          with its existing operations in the same areas.

     Pioneer's Reasons. Pioneer believes that completion of the merger of each
partnership is advantageous to it for the following reasons:

     o    Consolidate Core Area of Operations. The Spraberry field of the
          Permian Basin is one of Pioneer's 25 fields of focus in its strategic
          plan. Acquisition of each partnership's properties would help
          consolidate Pioneer's operations in the Spraberry field and achieve
          operating efficiencies. Pioneer USA operates most of each
          partnership's wells, and Pioneer has extensive properties around each
          partnership's properties, including interests in most of each
          partnership's wells.

     o    Achieve Operating Efficiencies. Pioneer expects to improve operating
          efficiencies with respect to the properties acquired in the merger of
          each partnership because it will be able to co-mingle production of
          oil from each participating partnership's properties with production
          of oil from other Pioneer properties for storage, transportation and
          sale. Production of oil from each partnership's properties is
          predominantly segregated from Pioneer's production of oil until sale.
          Gas production is currently, and will continue to be, metered.

     o    Achieve Administrative Efficiencies. Pioneer will eliminate the costs,
          including time spent by Pioneer employees, related to preparing and
          filing each partnership's separate tax returns, financial statements
          and, for each reporting partnership, reports with the SEC, as well as
          dealing with the concerns of approximately 29,000 record limited
          partners. The merger of each partnership will result in administrative
          efficiencies and cost reductions in the management and operation of
          the properties now owned by each partnership, particularly in the
          areas of audit, accounting and tax services, engineering services,
          bookkeeping, data processing, record maintenance and mailing
          information to the partners. Although Pioneer will lose the benefit of
          each partnership's reimbursement for general and administrative
          expenses, it will be able to use the additional time of its personnel
          to help achieve its corporate strategic goals.

     Pioneer USA's Reasons. In considering the merger of each partnership, the
board of directors of Pioneer USA considered the benefits to the limited
partners of each partnership set forth on page 7 as well as the following
factors:

     o    Maturity of Partnerships and Properties. Although each partnership's
          properties were long-lived at the formation of the partnership,
          Pioneer and Pioneer USA anticipated that at some point each
          partnership would need to be liquidated. Pioneer USA is recommending
          the merger transaction for each partnership at this time because:

          -    Pioneer is the most likely buyer and is the only potential buyer
               with an offer outstanding. While third parties have made
               inquiries, no one except Pioneer has made an offer to Pioneer USA
               to acquire any of the partnerships.

          -    Oil and gas prices have recovered from significant lows in 1998.
               As a result, Pioneer USA believes that Pioneer's pricing is
               higher than it would have been otherwise.

          -    Administrative expenses for each partnership are increasing.
               Moreover, the administrative cost of continuing to produce each
               partnership to depletion could be significant, especially if no
               buyer is available at the time each partnership is shut down.

          -    Each partnership's properties are mature, ranging from
               approximately 10 to approximately 20 years old. The benefits for
               which each partnership was originally formed have been realized.

     o    Declining Cash Flows. As each partnership's properties have matured,
          the net cash flows from operations for the partnership have generally
          declined, except in periods of substantially increasing commodity
          prices. See Table 7 of Appendix A for each partnership's historical
          cash distributions. The marginal benefit of continuing the operations
          of each partnership is offset by the related administrative costs.
          These



                                      -26-
   36

          administrative costs consume an increasing amount, and ultimately will
          consume the entire amount, of the cash flows of each partnership as
          production declines.

     o    Tax Incentives Have Been Realized. To the extent that each partnership
          was intended to provide tax incentives to its partners, those
          incentives have been realized, or the tax purposes for which the
          partnership was originally formed are no longer applicable as a result
          of changes in laws.

     o    Partnership Tax Burdens May Now Exceed Benefits. As net cash flow
          available for distribution of each partnership has declined or, at
          times, disappeared, some limited partners of the partnership may incur
          greater costs to include their share of the tax information of the
          partnership in their returns than they receive in cash distributions.
          In any event, all limited partners of each partnership are expected to
          benefit by the elimination of the obligation to include partnership
          information in their tax returns for the years after the merger of
          each partnership in which they own interests.

     o    Each Partnership is Unable to Access Additional Capital. Pioneer,
          through its subsidiary, Pioneer USA, has the ability, financial and
          otherwise, to take advantage of corporate opportunities to expand its
          reserve base through acquisitions. None of the partnerships has the
          ability to raise capital for reserve acquisitions. The partnership
          agreements of the partnerships do not authorize the partnerships to
          raise additional capital, whether debt or equity. Even if the
          partnership agreement of each partnership is amended to authorize
          additional capital, Pioneer does not believe that the limited partners
          of the partnership would desire to contribute additional capital or to
          apply all cash flow to debt service, while remaining taxable on the
          related income.

     o    Fairness of Procedures. Pioneer USA considered the following factors
          in making its recommendation that the unaffiliated limited partners
          vote for the merger proposals for each partnership in which they own
          interests:

          -    None of the partnerships has any employees or directors, and all
               of Pioneer USA's directors are officers of Pioneer USA and of
               Pioneer. As a result, there has been no approval by directors who
               are not Pioneer employees.

          -    Pioneer USA did not retain an unaffiliated representative to act
               solely on behalf of the unaffiliated limited partners of each
               partnership for purposes of negotiating the terms of the merger
               of the partnership or preparing a report concerning the fairness
               of the merger of the partnership.

          -    Since Pioneer USA is entitled to vote its limited partnership
               interests other than as described below, the transaction is not
               structured so that the approval of at least a majority of
               unaffiliated limited partnership interests is required. Pioneer
               USA intends to vote in favor of the transaction for the
               partnership interests it holds as a limited partner of each
               partnership as permitted by the partnership agreement of each
               partnership except in the following partnerships where the
               partnership agreement does not allow Pioneer USA to vote on the
               proposed transaction:

                      Parker & Parsley 85-A, Ltd.
                      Parker & Parsley 85-B, Ltd.
                      Parker & Parsley Private Investment 85-A, Ltd
                      Parker & Parsley Selected 85 Private Investment, Ltd
                      Parker & Parsley Private Investment 86, Ltd.
                      Parker & Parsley 91-A, L.P.
                      Parker & Parsley 91-B, L.P.

          Despite the foregoing factors, Pioneer USA believes each merger is
          procedurally fair to the unaffiliated limited partners of each
          partnership because:

          -    Pioneer USA has been willing to consider any offer from third
               parties to purchase any partnership or the assets of any
               partnership since September 8, 1999, and will continue to do so
               through July 31, 2001; and

          -    Pioneer does not directly own any partnership interests in the
               partnerships. Pioneer beneficially owns all of Pioneer USA's
               partnership interests in the partnerships. Pioneer USA does not
               beneficially own more than 5% of the outstanding limited
               partnership interests in any partnership, except Parker & Parsley
               81-I, Ltd., Parker & Parsley 82-I, Ltd. and Parker & Parsley
               82-III, Ltd. In those partnerships, Pioneer USA repurchased and
               now owns partnership interests representing the following
               beneficial ownership percentages:



                                      -27-
   37


                                                                   
                      Parker & Parsley 81-I, Ltd.                        5.84%
                      Parker & Parsley 82-1, Ltd.                       10.73%
                      Parker & Parsley 82-III, Ltd.                      5.97%


               Except as set forth above, none of Pioneer, Pioneer USA, or, to
               the knowledge of Pioneer USA, any of their directors or executive
               officers, or any associate or subsidiary of Pioneer, Pioneer USA
               beneficially owns any partnership interests of any partnership.
               As a result, Pioneer USA believes that neither it nor its
               affiliates have a meaningful voting percentage for any
               partnership, other than Parker & Parsley 81-I, Ltd., Parker &
               Parsley 82-I, Ltd. and Parker & Parsley 82-III, Ltd. See
               "Ownership of Partnership Interests" on page 61 of this document
               and Table 6 of Appendix A to this document.

     o    Fairness of Transaction. Pioneer USA's board of directors determined
          that the merger of each partnership is advisable, fair to the
          unaffiliated limited partners of the partnership and in their best
          interests. In reaching this determination for each partnership,
          Pioneer USA's board of directors considered the following factors:

          -    The form and amount of consideration offered to the partners of
               the partnership;

          -    The objectives of the merger of the partnership, including
               providing liquidity to the partners;

          -    Pioneer USA's right to consider third party offers;

          -    The current market prices for oil and gas, including the increase
               in market prices, and the subsequent increase in merger value for
               the partnership, since the merger transaction was initially
               proposed in 1999;

          -    The historical market prices for oil and gas;

          -    The net book value, going concern value and liquidation value of
               the partnership;

          -    The purchase prices paid in previous repurchases by Pioneer USA;

          -    The trading price of limited partnership interests in secondary
               market transactions

          -    The analysis of alternative transactions to the proposed merger
               of each partnership; and

          -    The fairness opinion of Stanger, including the analyses conducted
               by Stanger in rendering the fairness opinion.

PIONEER'S DISCLOSURE RELATING TO THE MERGER OF EACH PARTNERSHIP

     As directors of a company that is not the general partner of any of the
partnerships, Pioneer's board of directors believes that neither they nor
Pioneer has any fiduciary duties to the limited partners of any of the
partnerships. Accordingly, Pioneer's board has not made any determination as to
the fairness of the merger of each partnership to the unaffiliated limited
partners of the partnership. Pioneer's board believes that such a determination
is within the scope of the duties of Pioneer USA's board and not within the
scope of the duties of Pioneer's board. Nevertheless, Pioneer's board did take
note of the price negotiations between Pioneer and Pioneer USA on behalf of the
limited partners, as well as a number of the factors considered by Pioneer USA's
board, including (1) the reasons for the merger of each partnership set forth
above in "Special Factors -- Reasons for the Merger of Each Partnership," such
as the fairness opinion and analyses conducted by Stanger and the amount of
common stock and cash offered by Pioneer, and (2) the matters described under
"Risk Factors" beginning on page 17 of this document.

RECOMMENDATION OF PIONEER USA

     On          , 2001, Pioneer USA's board of directors unanimously determined
that the merger of each partnership is advisable, fair to the unaffiliated
limited partners of the partnership, and in their best interests. PIONEER USA'S
BOARD OF DIRECTORS RECOMMENDS THAT THE UNAFFILIATED LIMITED PARTNERS VOTE FOR
THE MERGER PROPOSALS FOR EACH PARTNERSHIP IN WHICH THEY OWN INTERESTS.

     In making this recommendation, Pioneer USA's board of directors considered
a number of factors, including (1) the reasons for the merger of each
partnership set forth above in "Special Factors -- Reasons for the Merger of
Each Partnership," such as the fairness opinion and analyses conducted by
Stanger, and (2) the matters described under "Risk Factors" beginning on page 17
of this document, such as its conflicting interests. Pioneer USA's board of
directors also considered the likelihood, benefits and costs of other
transactions, including possible third party offers. Pioneer USA will consider
any offers from third parties to purchase any partnership or its assets. See
"The Merger of Each Partnership -- Third Party Offers" on page 48 of this
document for a description of the procedures for these offers. In view of the
numerous factors taken into consideration, Pioneer USA's board of directors did
not



                                      -28-
   38

consider it practical to, and did not attempt to, quantify or assign relative
weights to the factors considered by it in reaching its decision to recommend
the merger of each partnership. Rather, the board viewed its position and
recommendation as being based on the total information presented to and
considered by the board.

FAIRNESS OPINION

     Pioneer USA, on behalf of each partnership, engaged Robert A. Stanger &
Co., Inc., an independent financial advisory firm, to conduct an independent
review and deliver a written opinion in connection with the merger of each
partnership that the merger value for each partnership and the allocation of the
merger value of the partnership (1) to the limited partners of the partnership
as a group, (2) to the general partners of the partnership as a group, (3) to
Pioneer USA as the managing or sole general partner of the partnership, (4) to
the unaffiliated limited partners of the partnership as a group and (5) to the
unaffiliated limited partners of the nonmanaging general partner, if any, of the
partnership as a group, is fair to the unaffiliated limited partners of the
partnership and the unaffiliated limited partners of the nonmanaging general
partner, if any, of the partnership, from a financial point of view. The full
text of Stanger's fairness opinion, which sets forth the assumptions,
limitations and qualifications applicable to the review by Stanger, is attached
as Appendix C to this document and is incorporated into this document by
reference. Limited partners of each partnership are urged to read the opinion in
its entirety. This summary of Stanger's fairness opinion is qualified in its
entirety by reference to the full text of the opinion. Stanger has advised us
that arriving at a fairness opinion is a complex analytical process not
necessarily susceptible to partial analysis or amenable to summary description.
For a more complete description of the assumptions and qualifications to the
fairness opinion see "Qualifications to Fairness Opinion" and "Assumptions"
below.

     Except for assumptions which Pioneer USA advised Stanger would be
reasonable and appropriate in its view, neither Pioneer USA nor any partnership
imposed any conditions or limitations on the scope of the investigation by
Stanger or the methods and procedures to be followed by Stanger in rendering the
fairness opinion. In addition, each partnership has agreed to indemnify Stanger
against some liabilities arising out of Stanger's engagement to prepare and
deliver its opinion upon consummation of the merger of the partnership, and such
indemnification obligations will become obligations of Pioneer USA.

     Experience of Stanger. Since its founding in 1978, Stanger has provided
information, research, investment banking and consulting services to clients
located throughout the United Sates, including major New York Stock Exchange
member firms and insurance companies and over seventy companies engaged in the
management and operation of partnerships. The investment banking activities of
Stanger include financial advisory and fairness opinion services, asset and
securities valuations, industry and company research and analysis, litigation
support and expert witness services, and due diligence investigations in
connection with both publicly registered and privately placed securities
transactions.

     Stanger was selected because of its experience in the valuation of
businesses and their securities in connection with mergers, acquisitions,
reorganizations and for estate, tax, corporate and other purposes, including the
valuation of partnerships, partnership securities and the assets typically held
through partnerships including oil and gas assets. Pioneer USA has previously
engaged Stanger to provide financial advisory services in connection with
proposed transactions between each partnership and Pioneer which were never
consummated.

     Qualifications to Fairness Opinion. In the fairness opinion, Stanger
specifically states that it was not requested to, and did not:

     o    make any recommendations to Pioneer USA, any partnership or the
          limited partners of any partnership with respect to whether to approve
          or reject the merger of any partnership;

     o    determine or negotiate the amount or form of the merger value for any
          partnership to be paid for limited partners' interests in the merger
          of the partnership;

     o    offer the assets of any partnership for sale to any third party;

     o    express any opinion as to:

          -    the impact on Pioneer USA or the limited partners of any
               partnership that does not participate in the proposed merger
               transaction;

          -    the tax consequences of the merger of any partnership for Pioneer
               USA, the nonmanaging general partner, if any, of the partnership
               or the limited partners of the partnership;

          -    Pioneer USA's or Pioneer's ability to finance their obligations
               under the merger agreement or the impact of a failure to obtain
               financing on the financial performance of Pioneer USA, Pioneer or
               any partnership;



                                      -29-
   39

          -    Pioneer USA's decision to estimate the reserve value of the oil
               and gas reserves of each partnership based upon the continued
               operation of the properties by Pioneer USA and the payment of
               overhead charges in accordance with existing operating agreements
               or the impact, if any, on the estimated value of each
               partnership's oil and gas reserves if Pioneer and Pioneer USA
               determined to offer or operate the assets subject to revised
               operating agreements;

          -    whether or not alternative methods of determining the merger
               value for each partnership would have also provided fair results
               or results substantially similar to the methodology used;

          -    alternatives to the merger of each partnership, including the
               offering of such assets for sale to third party buyers;

          -    the trading price of shares of Pioneer common stock immediately
               following the closing of the merger of each partnership and the
               distribution of shares of Pioneer common stock in connection with
               the merger of each partnership;

          -    the fairness of the termination of the repurchase obligations of
               Pioneer USA with respect to some partnerships, which repurchase
               obligations require Pioneer USA to offer to repurchase limited
               partnership interests annually based upon a formula which in some
               circumstances, including the repurchase offers based upon
               December 31, 2000 oil and gas prices, result in repurchase offer
               prices above the market value for the reserves of any such
               partnership; or

          -    any other terms of the merger of any partnership.

     Summary of Material Considered and Investigation Undertaken. Stanger's
analysis of the merger of each partnership involved a review of the following
information:

     o    a draft of this preliminary document;

     o    a draft of the merger agreement which Pioneer USA has indicated is
          substantially the form which will be executed in connection with the
          merger of each partnership;

     o    financial statements of each partnership, including, if applicable,
          the partnership's Form 10-K, for the years ended December 31, 2000,
          1999 and 1998;

     o    the reserve analysis for each partnership prepared by Pioneer and
          Pioneer USA as of March 31, 2001;

     o    the summary reserve report prepared by Williamson Petroleum
          Consultants, Inc., as of December 31, 2000, relating to the reserves
          of each partnership;

     o    calculations prepared by Pioneer and Pioneer USA of the merger value
          per $1,000 of limited partner investment in each partnership;

     o    Pioneer USA's analysis of other alternatives to the merger of each
          partnership, including going concern value, liquidation value, royalty
          trust and production payment;

     o    estimates prepared by Pioneer and Pioneer USA of the merger value,
          going concern value and liquidation value per $1,000 of limited
          partner investment in each partnership;

     o    the financial statements of Pioneer included in its Form 10-K for the
          years ended December 31, 2000, 1999 and 1998;

     o    pro forma financial data for Pioneer assuming the completion of the
          proposed merger transaction; and

     o    recent trading activity in shares of Pioneer common stock.

     In the course of its analysis, Stanger conducted interviews of senior
management personnel of Pioneer USA in April 2001. During such interviews,
Stanger and the senior management personnel reviewed the status of the merger of
each partnership, the reserve pricing and related value estimates, the estimated
timing of the merger of each partnership and other matters.

     Stanger reviewed estimates of the merger value, going-concern value, and
liquidation value prepared by Pioneer USA with respect to each partnership. In
addition, Stanger reviewed secondary market prices, as tracked by Stanger, for
limited partnership interests in each partnership along with tender offers
received by limited partners as derived from data provided by Pioneer USA.
Stanger's analysis is summarized below.



                                      -30-
   40

     Review of Merger Value for Each Partnership. Stanger reviewed the
calculation of the merger value for each partnership prepared by Pioneer USA.
Stanger observed that such calculation includes the reserve value, as described
below, and other current assets as of December 31, 2000, as reduced by other
current liabilities as of December 31, 2000. Stanger reviewed the balance sheet
of each partnership as of December 31, 2000 as prepared by Pioneer USA, and
reconciled the current assets and current liabilities on such financial
statements to the balances included in the merger value calculation for each
partnership.

     Stanger reviewed the summary reserve analysis for each partnership prepared
by Pioneer and Pioneer USA as of March 31, 2001. Stanger noted that the summary
reserve analysis was prepared based upon a pricing case of (1) a five-year NYMEX
futures price for oil and gas as of March 30, 2001, with prices held constant
after year five at the year five price and (2) historical operating costs
adjusted only for those items affected by commodity prices, such as production
taxes and ad valorem taxes. For 2001, the oil and gas prices were based on the
average NYMEX futures price for the nine-month period beginning on April 1, 2001
and ending December 31, 2001. The standard industry adjustments reflect oil
quality, BTU content, oil and gas gathering and transportation costs, and gas
processing costs and shrinkage.

     Stanger further observed that the reserve analysis utilized a discount rate
of 13.5% and resulted in a per barrel of oil equivalent, or BOE, value of the
reserves for each of the partnerships ranging from $3.07 to $4.02. Stanger
observed that such BOE values are low by general industry averages. However,
Stanger observed that such properties are long-lived, generally low-volume
properties, not operated by any of the partnerships, and are subject to overhead
charges by the operator, Pioneer USA. In the course of its engagement, Stanger
reviewed selected comparable transactions in the BOE value range described above
for long-lived, generally low-volume properties.

     Stanger reviewed the summary reserve report prepared by Williamson
Petroleum Consultants, Inc. dated as of December 31, 2000, relating to the
reserves of each partnership. Such report indicated that the analysis prepared
by Pioneer and Pioneer USA was prepared using industry standards and procedures,
based upon the pricing case provided.

     Going Concern Value. Stanger reviewed the going concern value calculation
prepared for each partnership by Pioneer USA. The going concern value was based
upon:

     o    The sum of (1) the estimated net cash flow from sale of the reserves
          during a 10-year operating period plus (2) the estimated residual
          value from the sale of the remaining reserves at the end of the
          operating period, in each case using the same pricing and discount
          rate as in the merger value calculation; less

     o    Partnership level general and administrative expenses, calculated as
          follows and, consistent with the calculation of 2000 and 1999
          expenses, generally representing the maximum expense percentages
          permitted under the partnership agreements:

          -    The partnership agreement for each of Parker & Parsley 81-I,
               Ltd., Parker & Parsley 81-II, Ltd., Parker & Parsley 82-I, Ltd.,
               Parker & Parsley 82-II, Ltd. and Parker & Parsley 82-III, Ltd.
               permits Pioneer USA to allocate to the partnership (1) general
               and administrative expenses and (2) all expenses directly
               attributable to the partnership as a result of fees or charges by
               parties other than Pioneer USA or its affiliates, including
               legal, auditing and engineering fees. However, for purposes of
               clause (1) and for administrative ease and to the benefit of each
               of those partnerships, Pioneer USA allocates to each of those
               partnerships general and administrative expenses based on 3% of
               the revenues of the partnership.

          -    The partnership agreement for each of Parker & Parsley 83-A, Ltd.
               and Parker & Parsley 83-B, Ltd. permits Pioneer USA to allocate
               to the partnership (1) general and administrative expenses in an
               annual amount not to exceed the sum of 2% of the initial partner
               capital for the partnership, plus 2.25% of the drilling and
               completion expenses, of which there are none, and (2) all
               expenses directly attributable to the partnership as a result of
               fees or charges by parties other than Pioneer USA or its
               affiliates, including legal, auditing and engineering fees.
               However, for purposes of clause (1) and for administrative ease
               and to the benefit of each of those partnerships, Pioneer USA
               allocates to each of those partnerships general and
               administrative expenses based on 3% of the revenues of the
               partnership.

          -    The partnership agreement for Parker & Parsley 84-A, Ltd. permits
               Pioneer USA to allocate to the partnership (1) general and
               administrative expenses in an annual amount not to exceed the sum
               of 3.25% of the revenues of the partnership, plus 2.25% of the
               drilling and completion expenses, of which there are none, and
               (2) all expenses directly attributable to the partnership as a
               result of fees or charges by parties other than Pioneer USA or
               its affiliates, including legal, auditing and engineering fees.
               However, for purposes of clause (1) and for administrative ease
               and to the benefit of the partnership, Pioneer USA allocates to
               the partnership general and administrative expenses based on 3%
               of the revenues of the partnership.



                                      -31-
   41

          -    The partnership agreement for each of the following partnerships
               permits Pioneer USA to allocate to the partnership general and
               administrative expenses, including all expenses directly
               attributable to the partnership as a result of fees or charges by
               parties other than Pioneer USA or its affiliates, such as legal,
               auditing and engineering fees, in an annual amount not to exceed
               2% of the revenues of the partnership.

                  Parker & Parsley Private Investment 85-A, Ltd.
                  Parker & Parsley Selected 85 Private Investment, Ltd.
                  Parker & Parsley Private Investment 86, Ltd.

          -    The partnership agreement for each of the following partnerships
               permits Pioneer USA to allocate to the partnership general and
               administrative expenses, including all expenses directly
               attributable to the partnership as a result of fees or charges by
               parties other than Pioneer USA or its affiliates, such as legal,
               auditing and engineering fees, in an annual amount not to exceed
               3% of the revenues of the partnership.

                  Parker & Parsley 85-A, Ltd.
                  Parker & Parsley 85-B, Ltd.
                  Parker & Parsley 86-A, Ltd.
                  Parker & Parsley 86-B, Ltd.
                  Parker & Parsley 86-C, Ltd.
                  Parker & Parsley 87-A Conv., Ltd.
                  Parker & Parsley 87-A, Ltd.
                  Parker & Parsley 87-B Conv., Ltd.
                  Parker & Parsley 87-B, Ltd.
                  Parker & Parsley Producing Properties 87-A, Ltd.
                  Parker & Parsley Producing Properties 87-B, Ltd.
                  Parker & Parsley Private Investment 87, Ltd.
                  Parker & Parsley 88-A Conv., L.P.
                  Parker & Parsley 88-A, L.P.
                  Parker & Parsley 88-B Conv., L.P.
                  Parker & Parsley 88-B, L.P.
                  Parker & Parsley 88-C Conv., L.P.
                  Parker & Parsley 88-C, L.P.
                  Parker & Parsley Producing Properties 88-A, L.P.
                  Parker & Parsley Private Investment 88, L.P.

          -    The partnership agreement for each of the following partnerships
               permits Pioneer USA to allocate to the partnership (1) general
               and administrative expenses in an annual amount not to exceed 3%
               of the revenues of the partnership, and (2) all expenses directly
               attributable to the partnership as a result of fees or charges by
               parties other than Pioneer USA or its affiliates, including
               legal, auditing and engineering fees.

                  Parker & Parsley 89-A Conv., L.P.
                  Parker & Parsley 89-A, L.P.
                  Parker & Parsley 89-B Conv., L.P.
                  Parker & Parsley 89-B, L.P.
                  Parker & Parsley 90-A Conv., L.P.
                  Parker & Parsley 90-A, L.P.
                  Parker & Parsley 90-B Conv., L.P.
                  Parker & Parsley 90-B, L.P.
                  Parker & Parsley 90-C Conv., L.P.
                  Parker & Parsley 90-C, L.P.
                  Parker & Parsley 91-A, L.P.
                  Parker & Parsley 91-B, L.P.

          -    The partnership agreement for each of the following partnerships
               permits Pioneer USA to allocate to the partnership (1) general
               and administrative expenses in an annual amount not to exceed 5%
               of the revenues of the partnership, and (2) all expenses directly
               attributable to the partnership as a result of fees or charges by
               parties other than Pioneer USA or its affiliates, including
               legal, auditing and engineering fees. However, for purposes of
               clause (1) and for administrative ease and to the benefit of each
               of the partnerships, Pioneer USA allocates to the partnership
               general and administrative expenses based on 3% of the revenues
               of the partnership.



                                      -32-
   42

                  Parker & Parsley Private Investment 89, L.P.
                  Parker & Parsley Private Investment 90, L.P.
                  Parker & Parsley 90 Spraberry Private Development, L.P.

     Stanger observed that the going concern value of each partnership ranged
from 7.2% to 11.5% less than the merger value for each partnership. See the
supplemental information table on the second page of the supplement for each
partnership for its merger value and its going concern value, in each case per
$1,000 limited partner investment.

     Liquidation Value. Stanger reviewed the liquidation value calculation
prepared for each partnership by Pioneer USA. Such liquidation value was based
upon the sale of the reserves at the reserve value, less merger expenses
estimated at 3% of reserve value. The 3% estimate of merger expenses was based
upon the estimated costs to retain an investment banker or broker to sell the
assets of each partnership and the legal and other closing costs associated with
such transaction. Stanger observed that such merger expenses are intended to
reflect Pioneer USA's estimate of the cost associated with brokers' commissions
on asset sales and the additional wind-down costs of the partnership. Stanger
observed that the liquidation value for each partnership ranged from 2.5% to
2.7% less than the merger value for each partnership. See the supplemental
information table on the second page of the supplement for each partnership for
its merger value and its liquidation value, in each case per $1,000 limited
partner investment.

     Secondary Market Prices. To determine the most up-to-date secondary market
prices, Stanger reviewed the secondary market prices for units of limited
partnership interests in each of the partnerships during the 12 months ended
February 28, 2001, collected from data maintained on partnerships by Stanger.
Stanger observed that secondary market transactions were reported for 24 of the
partnerships during such period. Stanger observed that for all partnerships
except Parker & Parsley Producing Properties 87-A, Ltd., the weighted average
secondary market price on a per $1,000 original investment basis was less than
the merger value per $1,000 original investment. For such other partnerships,
the range of discount to the merger value per $1,000 investment was 3.6% to
53.7%, averaging 32.1%. For Parker & Parsley Producing Properties 87-A, Ltd.,
Stanger observed that only one transaction involving $10,000 of original
investment (20 units) was at a price in excess of the merger value per $1,000 of
original investment. All other secondary market transactions for Parker &
Parsley Producing Properties 87-A, Ltd. were reported at prices below the merger
value. Stanger also observed secondary market transactions at prices in excess
of the merger value for two additional partnerships. Secondary market firms
reported a single transaction during the twelve months ended February 28, 2001
for each of Parker & Parsley 85-B, Ltd. and Parker & Parsley 90-B, L.P. at a
price in excess of merger value. Each such transaction involved ten units
($10,000) of original investment. All other transactions reported for such
partnerships were at amounts less than the merger value during the twelve months
ended February 28, 2001.

     Stanger also reviewed the secondary market data obtained by Pioneer USA
from Partnership Spectrum and included in Table 15 of Appendix A to this
document. Stanger observed that such data included three partnerships which
reported a secondary market transaction price in excess of the high-end
transaction price Stanger observed in its data. In all cases, such high-end
range was lower than the merger value.

     Selected Tender Offers. Stanger observed that Pioneer USA reported
unsolicited tender offers from unaffiliated third parties for less than 5% of
the interests in the following partnerships during the period June 1998 through
March 2001. Stanger observed that the tender offers and related merger value per
limited partnership interest for each of those partnerships were as follows:



                                                       MERGER VALUE       TENDER OFFER
                                                       (PER $1,000         (PER $1,000          DISCOUNT TO
                    PARTNERSHIP                         INVESTMENT)        INVESTMENT)         MERGER VALUE
                                                       ------------     ----------------     ----------------
                                                                                    
Parker & Parsley 82-II, Ltd.                           $      98.29     $          13.75                (86.0)%
Parker & Parsley 82-III, Ltd.                                120.01                26.25                (78.1)
Parker & Parsley 83-A, Ltd.(a)                               138.67       40.00 to 70.00      (49.5) to (71.2)
Parker & Parsley 83-B, Ltd.(a)                               150.46       50.00 to 55.00      (63.4) to (66.8)
Parker & Parsley 84-A, Ltd.                                  193.75                60.00                (69.0)
Parker & Parsley 86-A, Ltd.                                  168.12                40.00                (76.2)
Parker & Parsley 86-B, Ltd.                                  218.28               115.00                (47.3)
Parker & Parsley 86-C, Ltd.(a)                               162.51       65.00 to 67.50      (58.5) to (60.0)
Parker & Parsley 87-A, Ltd.(a)                               187.59      90.00 to 105.00      (44.0) to (52.0)
Parker & Parsley 87-B, Ltd.(a)                               198.15       60.00 to 65.00      (83.4) to (84.7)
Parker & Parsley 88-A, L.P.                                  239.09                80.00                (66.5)
Parker & Parsley 88-B, L.P.                                  309.73                50.00                (83.8)
Parker & Parsley Private Investment 89, L.P.                 259.94               162.50                (32.5)
Parker & Parsley 90-B, L.P.(a)                               258.68     102.50 to 160.00      (38.2) to (60.4)
Parker & Parsley 90-C, L.P.(a)                               238.17       30.00 to 40.00      (83.2) to (87.4)
Parker & Parsley 90 Spraberry Private Dev., L.P.             274.15               162.50                (40.7)




                                      -33-
   43

----------

(a)  More than one tender offer for partnership interests was made. Amounts
     shown represent the range of tender offer prices.

     Stanger observed that the above tender offers represent a discount to the
merger value for each of those partnerships of 32.5% to 87.4%. Stanger also
observed that tender offers for limited partnership securities are generally at
prices which represent a substantial discount to the underlying value of the
assets held by such partnerships. Furthermore, the tender offer prices are based
on oil prices prevailing at the time of the tender offer, which prices may have
been lower than oil prices prevailing at March 30, 2001 or as of the date of
mailing this document.

     Repurchase Offers. Stanger observed that for each of the six partnerships
listed below, which Stanger calls the repurchase partnerships, Pioneer USA is
required under the partnership agreement for the partnership to offer to
repurchase units of limited partnership interests in the partnership annually at
a formula price based upon the December 31 year end reserve report. Stanger
observed that the repurchase offer pricing at December 31, 2000 tends to
overstate the value of units of the repurchase partnerships due primarily to the
oil and gas prices in effect on such date and the effect of such pricing on the
cash flows and recoverable reserves. Stanger observed that the repurchase offers
for 2000 for the repurchase partnerships are at premiums to the merger value
ranging from 25.5% to 68.5% as follows:



                                                  PER $1,000 ORIGINAL INVESTMENT
                                        ----------------------------------------------------
                                         MERGER VALUE     REPURCHASE OFFER       PREMIUM
                                        --------------    ----------------    --------------
                                                                     
Parker & Parsley 82-I, Ltd.             $        81.87     $       137.97               68.5%
Parker & Parsley 82-II, Ltd.                     98.29             133.72               36.0
Parker & Parsley 82-III, Ltd.                   120.01             150.59               25.5
Parker & Parsley 83-A, Ltd.                     138.67             196.67               41.8
Parker & Parsley 83-B, Ltd.                     150.46             210.15               39.7
Parker & Parsley 84-A, Ltd.                     193.75             267.03               37.8


     Stanger further observed that Pioneer USA's obligation is limited to
$100,000 in repurchases per year per repurchase partnership. Stanger further
advised Pioneer USA and the repurchase partnerships that no adjustment was made
to the merger value offered to the repurchase partnerships to reflect the
repurchase offer obligation and Stanger's opinion does not include an opinion as
to the fairness of the termination of Pioneer USA's repurchase obligation.

     Assumptions. Pioneer and Pioneer USA advised Stanger that the oil and gas
properties owned by each partnership are subject to operating agreements with
Pioneer USA and that:

     o    such operating agreements provide for the payment of overhead charges
          and that such charges are reasonable compared with amounts charged for
          similar services by third party operators;

     o    except for cause, such operating agreements do not provide for the
          termination of Pioneer USA as operator; and

     o    such operating agreements do not provide for the revision of the
          overhead charges, except as escalated under the terms of such
          operating agreements.

Furthermore, Pioneer and Pioneer USA advised Stanger that if each partnership's
reserves were offered for sale to a third party, a condition of such sale would
be that the oil and gas reserves would continue to be subject to the operating
agreements with Pioneer USA which provide for the payment of overhead charges,
and that it would be appropriate to assume, when estimating the value of such
reserves, that such charges would continue.

     In addition, Pioneer and Pioneer USA advised Stanger that the reserve value
and working capital balance of each partnership has been properly allocated
between the general partners and the limited partners of each partnership in
accordance with the partnership agreement with respect to a liquidation.

     Stanger did not conduct any engineering studies and has relied on estimates
of Pioneer and Pioneer USA with respect to oil and gas reserve volumes, prices,
operating costs and overhead charges with respect to the reserve value
estimates.



                                      -34-
   44

     Stanger also relied on the assurance of Pioneer, Pioneer USA and each
partnership that:

     o    the reserve analysis provided to Stanger was in the judgement of
          Pioneer USA and each partnership reasonably prepared on bases
          consistent with actual historical experience and reflect their best
          currently available estimates and good faith judgements;

     o    there are no estimates of costs to remediate environmental conditions
          included in the reserve analysis;

     o    any historical financial data, balance sheet data, merger value
          analyses, going concern value analyses and liquidation value analyses
          are accurate and complete in all material respects;

     o    all allocations included in the calculations of merger values, going
          concern values and liquidation values have been made in accordance
          with the partnership agreement of each partnership;

     o    no material changes have occurred in the information reviewed or in
          the value of the oil and gas reserves or working capital balances of
          each partnership between the date the information was provided to
          Stanger and the date of Stanger's opinion;

     o    the relative ownership interests of (1) the limited partners of each
          partnership, (2) the unaffiliated limited partners of each
          partnership, (3) the general partners of each partnership, (4) the
          unaffiliated limited partners of the nonmanaging general partner, if
          any, of each partnership and (5) Pioneer USA, as the managing or sole
          general partner of each partnership, is accurately included in
          accordance with the partnership agreement for each partnership in the
          analyses provided to Stanger by Pioneer USA;

     o    neither Pioneer or any of its affiliates has during the thirty days
          prior to the date hereof commenced or continued a share repurchase
          program or similar transaction which could affect the price of shares
          of Pioneer common stock to be used in the proposed merger transaction;
          and

     o    Pioneer, Pioneer USA and each partnership are not aware of any
          information or facts regarding the partnership, the oil and gas
          properties, the reserve analysis or the working capital balances of
          the partnership that would cause the information supplied to Stanger
          to be incomplete or misleading in any material respect.

     Stanger's opinion is based upon business, economic, oil and gas market and
other conditions as of the date of its analysis and addresses the merger value
for each partnership in the context of information available as of the date of
Stanger's analysis. Events occurring after the date of Stanger's analysis could
affect the value of the assets of each partnership or the assumptions used in
the preparation of Stanger's fairness opinion.

     Conclusions. Stanger concluded that, based upon and subject to its
analysis, assumptions, limitations and qualifications cited in its opinion, and
as of the date of the fairness opinion, the merger value for each partnership
and the allocation of the merger value of the partnership (1) to the limited
partners of the partnership as a group, (2) to the general partners of the
partnership as a group, (3) to Pioneer USA as the managing or sole general
partner of the partnership, (4) to the unaffiliated limited partners of the
partnership as a group and (5) to the unaffiliated limited partners of the
nonmanaging general partner, if any, of the partnership as a group, is fair to
the unaffiliated limited partners of the partnership and the unaffiliated
limited partners of the nonmanaging general partner, if any, of the partnership,
from a financial point of view.

     Compensation and Material Relationships. Stanger has been paid a total fee
of $350,000 in connection with the rendering of the fairness opinion. Such fee
was not conditioned on Stanger's findings and is payable whether or not the
merger of each partnership is consummated. In addition, Stanger will be
reimbursed for all reasonable out-of-pocket expenses, including legal fees, and
will be indemnified against some liabilities, including some liabilities under
the securities laws. To the extent that such indemnification includes
liabilities arising under the federal securities laws, it may not be enforceable
as it may be determined to be against public policy.

     During the past two years, Pioneer USA engaged Stanger to render financial
advisory services in connection with proposed transactions which were withdrawn
and never consummated. In connection with such assignments Stanger was paid fees
aggregating $175,000.

SUMMARY RESERVE REPORT

     Pioneer USA engaged Williamson Petroleum Consultants, Inc., an independent
petroleum engineering consulting firm based in Midland, Texas, to provide a
summary reserve report of the property interests of each of the partnerships as
of December 31, 2000. THE FULL TEXT OF THE SUMMARY RESERVE REPORT OF WILLIAMSON
PETROLEUM CONSULTANTS, INC. EFFECTIVE AS OF DECEMBER 31, 2000, WHICH SETS FORTH
THE MATTERS CONSIDERED, ASSUMPTIONS MADE AND LIMITATIONS, IS ATTACHED AS
APPENDIX B. WE ENCOURAGE YOU TO READ IT CAREFULLY IN ITS ENTIRETY.



                                      -35-
   45

     Qualifications and Method of Selection. Williamson is engaged solely in the
business of petroleum evaluation and engineering studies for public and private
oil and gas companies. Williamson is widely recognized in its field. Williamson
is an independent consulting firm as provided in the Standards Pertaining to the
Estimating and Auditing of Oil and Gas Reserves Information promulgated by the
Society of Petroleum Engineers.

     Pioneer USA engaged Williamson based upon Pioneer USA's assessment of their
professional reputations and qualifications, capabilities, experience and
responsiveness. In addition, Williamson is the independent petroleum engineering
firm most familiar with the properties in which each partnership has interests
and has prepared the annual independent reserve report for each partnership's
reserves since the inception of each partnership.

     Summary of Procedures, Scope and Findings. Williamson calculated the
estimated total net proved reserves for each partnership and the present value
of the estimated future net revenues from the estimated proved reserves for each
partnership as of December 31, 2000, based on the financial reporting
requirements of the SEC, including using NYMEX spot oil and gas prices as of
December 31, 2000, which were $26.69 per Bbl of oil and $9.95 per Mcf of gas.
Williamson's estimated total net proved reserves and the present value of the
estimated future net revenues from the reserves for each partnership are set
forth in the exhibits to the summary reserve report attached as Appendix B to
this document.

     Pioneer determined the amount of Pioneer common stock and cash to be
offered. Williamson did not opine on the fairness of the transaction.

     In preparing its summary reserve report, Williamson assumed the accuracy
and completeness of all information provided by Pioneer USA or information which
was publicly available and did not attempt to independently verify such
information. Williamson did not make field inspections or judgments relative to
environmental or other legal liabilities. Except as described below, Pioneer USA
did not instruct Williamson as to the pricing, cost or other economic parameters
or methods or the assessment of reserves characteristics, nor did it limit the
scope of Williamson's investigation for purposes of preparing its summary
reserve report.

     Pioneer USA provided Williamson with all evaluation data with respect to
interests, reversionary status, oil and gas prices, gas categories, gas contract
terms, operating expenses, investments, salvage values, abandonment costs, net
profit interests, well information and current operating conditions for
Williamson's use in determining each partnership's reserves. Williamson used
production data provided by Pioneer USA, and where information was not provided
by Pioneer USA, Williamson used production data from public records. Williamson
prepared its own reserve estimates of the property interests.

     Prior Material Relationships. Williamson has estimated total proved
reserves and the present value of estimated future revenues from those reserves
for each of the partnerships since their respective inceptions. In addition,
Pioneer USA engaged Williamson to prepare a summary reserve report in connection
with a proposed transaction in 1999, similar to the one described in this
document, which was withdrawn and never consummated. Pioneer USA and its
affiliates have paid $112,700 over the past two years to Williamson. Neither
Williamson nor any of its personnel has any direct or indirect interest in
Pioneer USA or any of the partnerships, and Williamson's compensation is not
contingent upon the results of its summary reserve report.

ALTERNATIVE TRANSACTIONS TO THE MERGER OF EACH PARTNERSHIP

     We considered the following alternative types of transactions before
selecting the merger transaction described in this document. As discussed below,
we believe that the merger of each partnership is the best available alternative
for each partnership to maximize the consideration to the limited partners.

     Comparison of the Merger of Each Partnership to Continuing Operations.
Because each partnership's properties are mature, producing properties, we
believe that production from those properties will continue to decline at the
rate predicted in the partnership's oil and gas engineering reserve reports.
Accordingly, cash distributions from each partnership will also decline, subject
to variation for changes in oil and gas prices. The marginal benefit of
continuing operations of each partnership is offset by the general and
administrative costs related to continuing operations. See "Special Factors --
Reasons for the Merger of Each Partnership" beginning on page 26 of this
document.

     We also believe there is a substantial advantage in receiving the
liquidating distribution at present in the form of Pioneer common stock and a
lump sum cash payment, rather than continuing to receive decreasing levels of
cash distributions over a long period of time. We believe that the reserve value
included in the merger value for each partnership is higher than the net present
value of estimated future cash distributions to the limited partners from
continued operations because the reserve value has not been reduced for the
reimbursement of Pioneer USA's general and administrative expenses allocable to
the partnership. In addition, continued operations over a long period of time
subject the limited partners of each partnership to the risk of receiving lower
levels of cash distributions if oil and gas prices over this period are lower on
average than those used in preparing the estimates of



                                      -36-
   46

cash distributions from continued operations. Continued operations also subject
the limited partners of each partnership to possible changes in costs or need
for workover or similar significant remedial work on each partnership's
properties. In contrast, the Pioneer common stock is a liquid tradeable security
which can be sold and redeployed in other investments. The Pioneer common stock
provides the limited partners of each partnership the opportunity to participate
in a larger entity having more diversified producing reserves and other oil and
gas properties, with the resulting spreading of risks.

     We expect that any nonparticipating partnership will continue operations
and will produce its reserves until depletion with steadily decreasing rates of
cash flow and, as a result, decreasing cash distributions.

     Comparison of the Merger of Each Partnership to Master Limited Partnership.
We considered accomplishing the consolidation of each partnership through a
master limited partnership, pursuant to which the partnership interests of the
limited partners of the partnership would be exchanged for interests in the
master limited partnership. However, each partnership's oil and gas properties
are not of sufficient size, individually or in the aggregate with the other
partnerships, to attract new capital through a master limited partnership. In
addition, the partnership interests in a master limited partnership might not be
traded on a national stock exchange or in any other significant market. Some
master limited partnership interests might be sold from time to time in private
or over-the-counter transactions, but the prices would likely reflect a discount
for illiquidity. As a result, a master limited partnership would not provide the
limited partners with immediate and complete liquidity for their investment in
each partnership. Finally, a master limited partnership would still be burdened
with general and administrative expenses, which would reduce any cash
distributions paid to the partners of the master limited partnership. The merger
value for each partnership reflects a liquidation value and has not been reduced
for any reimbursement of Pioneer USA's general and administrative expenses
allocable to the partnership.

     Comparison of the Merger of Each Partnership to Royalty Trust. We also
considered a royalty trust, pursuant to which the partnership interests of each
partnership would be exchanged for beneficial ownership interests in the trust.
Like the master limited partnership alternative discussed above, each
partnership's oil and gas properties are not of sufficient size, individually or
in the aggregate with the other partnerships, to attract new capital through a
royalty trust. In addition, the beneficial ownership interests in a royalty
trust might not be publicly traded in a significant market. As a result, this
alternative was not selected because it would not result in immediate and
complete liquidity for the limited partners' investments in any partnership.
Finally, a royalty trust would still be burdened with general and administrative
expenses, which would reduce any cash distributions paid to the beneficiaries of
the royalty trust. The merger value for each partnership reflects a liquidation
value and has not been reduced for any reimbursement of Pioneer USA's general
and administrative expenses allocable to the partnership.

     Comparison of the Merger of Each Partnership to Production Payment. We also
considered whether each partnership would benefit from attempting to sell a
production payment against its future oil and gas production in exchange for
cash. Like the master limited partnership and royalty trust alternatives
discussed above, each partnership's oil and gas properties are not of a
sufficient size, individually or in the aggregate with the other partnerships,
to attract new capital from lenders or investors. In addition, lenders or
investors that provide production payment alternatives will not advance funds
against 100% of future oil and gas production, and typically limit any
production payment transaction to less than 70% of estimated future oil and gas
production. As a result, this alternative was not selected because it would not
provide the limited partners with immediate and complete liquidity for their
investment in each partnership. Even with a production payment transaction, each
partnership would continue to be burdened with general and administrative
expenses which would reduce any cash distributions paid to the limited partners.
The merger value for each partnership reflects a liquidation value and has not
been reduced for any reimbursement of Pioneer USA's general and administrative
expenses allocable to the partnership.

     Comparison of the Merger of Each Partnership to Negotiated Sale. We also
considered whether each partnership would benefit from attempting to sell its
property interests in negotiated transactions. Buyers would be purchasing the
partnership's property interests which they would neither control nor operate. A
portion of the properties in which each partnership owns interests would
continue to be operated by Pioneer USA because Pioneer USA controls other
interests in fields in which the partnership's properties are located. Because
of Pioneer USA's control of such properties, Pioneer and Pioneer USA believe
Pioneer is the party in the position to pay the highest price for such interests
and the one most likely to do so. In contrast, Pioneer USA's control of such
properties could negatively affect the amount a third party is willing to pay
and the overall interest of third parties in buying such properties.

     In addition, sale of each partnership's properties on a direct basis often
involves substantial periods of time for due diligence, negotiation and
execution of agreements and closings, often with different purchasers for
different properties. Satisfying due diligence requests requires large amounts
of time to create and supervise data rooms or disseminate data to possible
purchasers, plus the time needed to deal directly with multiple prospective
purchasers. Furthermore, some issues, such as environmental and title matters,
may come to light in the late stages of a negotiated sale, which may delay or
preclude the consummation of the sale.



                                      -37-
   47

     The transaction costs for offering properties in a negotiated sale could be
substantial, and often are higher than other means of sale. Those costs include:

     o    preparing and disseminating information on properties to be offered;

     o    soliciting attendance by prospective purchasers; and

     o    screening and qualifying purchasers.

     In a third party sale, we expect that each partnership would have to pay
its own expenses or that the price would be reduced to take the expenses into
account. In contrast, Pioneer is paying all the expenses of the proposed merger
of each partnership.

     Although we believe the factors described above to be true, we are
conducting a limited form of auction. That is, in September 1999 we established
a price and publicly announced that we will consider third party offers to
purchase any partnership or its assets at prices that are higher than the 1999
merger value for such partnership. We have repeated our willingness to consider
third party offers in connection with the merger of each partnership we now
propose, so long as the prices offered exceed those we are offering. We believe
this process would result in a better price to the limited partners than if we
merely offered the partnership or its assets for sale at any price. See "The
Merger of Each Partnership -- Third Party Offers" on page 48. Although we
received some preliminary indications of interest from third parties during the
last quarter of 1999, none of those third parties has ever made a formal bid for
any partnership or its assets.

                           FORWARD-LOOKING STATEMENTS

     This document includes "forward looking statements" as defined by the
Securities and Exchange Commission. These statements concern Pioneer's, Pioneer
USA's and each partnership's plans, expectations and objectives for future
operations. All statements, other than statements of historical facts, included
in this document that address activities, events or developments that Pioneer,
Pioneer USA and each partnership expect, believe or anticipate will or may occur
in the future are forward looking statements and include the following:

     o    completion of the proposed merger of each partnership;

     o    reserve estimates;

     o    future production of oil and gas; and

     o    future financial performance.

     These forward looking statements are based on assumptions, which Pioneer,
Pioneer USA and each partnership believe are reasonable, but which are open to a
wide range of uncertainties and business risks. Factors that could cause actual
results to differ materially from those anticipated are discussed in (1)
periodic filings with the Securities and Exchange Commission, including Annual
Reports on Form 10-K for the year ended December 31, 2000, for Pioneer and each
partnership subject to the informational requirements of the Securities Exchange
Act of 1934, and (2) "Management's Discussion and Analysis of Financial
Condition and Results of Operations" for the year ended December 31, 2000
included in the supplement to this document for each partnership not subject to
the informational requirements of the Securities Exchange Act of 1934.

     "Safe Harbor" Statement under the Private Securities Litigation Reform Act
of 1995: Statements in this document regarding each company's business which are
not historical facts are "forward looking statements" that involve risks and
uncertainties. For a discussion of these risks and uncertainties, which could
cause actual results to differ from those contained in the forward looking
statements, see "Risk Factors" beginning on page 17 of this document.



                                      -38-
   48

             METHOD OF DETERMINING MERGER VALUE FOR EACH PARTNERSHIP
               AND AMOUNT OF PIONEER COMMON STOCK AND CASH OFFERED

     Pioneer and Pioneer USA agreed to a merger value for each partnership for
purposes of the merger of the partnership. The merger value for each partnership
has not been reduced by the projected costs and expenses of the partnership's
merger, which Pioneer will pay. The method of determining the merger value for
each partnership was not determined by arm's-length negotiations. See "Risk
Factors -- You Were Not Independently Represented in Establishing the Terms of
the Merger of Each Partnership" on page 17 and "Interests of Pioneer, Pioneer
USA and Their Directors and Officers" on page 60.

     Pioneer and Pioneer USA agreed to use March 31, 2001 to determine the
merger value for each partnership and to base the number of shares of Pioneer
common stock to be offered on the average closing price of the Pioneer common
stock, as reported by the New York Stock Exchange, for the ten trading days
ending three business days before the date of the special meeting for each
partnership. For purposes of illustration in this document, we have calculated
the merger value based on each partnership's working capital as of December 31,
2000, and the number of shares to be issued based on an assumed average closing
price of $18.00 per share of Pioneer common stock. We will update the
calculation of the merger value using the March 31, 2001 working capital of each
partnership before mailing this document to the limited partners, and prior to
the date of the special meeting for each partnership, we will update the number
of shares to be issued using the actual average closing price of Pioneer common
stock for the ten trading days ending three business days before the date of the
special meeting. Neither Pioneer nor Pioneer USA will adjust any of the other
components of the merger value for any partnership.

COMPONENTS OF MERGER VALUE FOR EACH PARTNERSHIP

     Pioneer and Pioneer USA calculated the merger value assigned to each
partnership as follows:

     o    Pioneer and Pioneer USA calculated the volumes of the partnership's
          proved reserves as of March 31, 2001, based on a future production
          curve consistent with the production curve used in the summary reserve
          report of Williamson Petroleum Consultants, Inc. as of December 31,
          2000. The reserve value component of the merger value for each
          partnership is also set forth in Table 12 of Appendix A to this
          document. Pioneer and Pioneer USA believe it is appropriate to use the
          production costs, excluding those items affected by commodity prices
          such as production taxes and ad valorem taxes, assumed in the 2000
          Williamson reserve report because such costs have been fairly stable
          and predictable over the last several years. However, Pioneer and
          Pioneer USA recalculated the economic limit, or point at which
          production would become unprofitable, otherwise assumed in the 2000
          Williamson reserve report because that reserve report used NYMEX spot
          oil and gas prices as of December 31, 2000, which were $26.69 per Bbl
          of oil and $9.95 per Mcf of gas. In contrast, Pioneer and Pioneer USA
          used the pricing case as of March 30, 2001, as described below. Based
          on this pricing, production would not be profitable for as long of a
          period of time as assumed in the 2000 Williamson reserve report.

     o    Pioneer and Pioneer USA calculated the present value of estimated
          future net revenues for each partnership from the estimated reserves
          for each partnership at March 31, 2001. Pioneer and Pioneer USA used
          the following parameters: (1) a five-year NYMEX futures price for oil
          and gas as of March 30, 2001, with prices held constant after year
          five at the year five price, less standard industry adjustments, (2)
          historical operating costs adjusted only for those items affected by
          commodity prices, such as production taxes and ad valorem taxes, and
          (3) a discount rate of 13.5%. For 2001, the oil and gas prices were
          based on the average NYMEX futures price for the nine-month period
          beginning on April 1, 2001 and ending December 31, 2001. See the table
          on page 6 for the NYMEX futures prices. Pioneer and Pioneer USA
          believe that the five-year NYMEX futures prices provide a reasonable
          benchmark on the outlook for energy prices and are regularly used by
          financial markets, industry participants, and lenders in evaluating
          transactions.

          -    The standard industry price adjustments include:

               (1)  the effects of oil quality;

               (2)  British thermal unit, or BTU, content for gas;

               (3)  any bonus paid;

               (4)  oil and gas gathering and transportation costs; and

               (5)  gas processing costs and shrinkage.

               Those adjustments reflect assumptions about the costs to extract,
               transport and process, if necessary, crude oil, natural gas
               liquids and natural gas to their point of sale.



                                      -39-
   49

          -    Pioneer and Pioneer USA believe the 13.5% discount rate is within
               the range of discount rates commonly used in the oil and gas
               industry in property acquisitions of producing properties,
               although it is higher than the 10% rate that the Securities and
               Exchange Commission requires for comparative purposes in the
               year-end reports of publicly owned oil and gas companies.

     o    Pioneer and Pioneer USA added the present value of the partnership's
          estimated future net revenues as of March 31, 2001 to the
          partnership's net working capital as of March 31, 2001. For purposes
          of illustration in this document, Pioneer and Pioneer USA calculated
          the net working capital portion of each merger value as of December
          31, 2000. Pioneer and Pioneer USA intend to update each net working
          capital value as of March 31, 2001, before mailing this document to
          the limited partners. Since the merger value for each partnership
          includes net working capital, the merger value assigned to the
          partnership includes the partnership's assets and liabilities other
          than its oil and gas reserves. Each partnership's other assets and
          liabilities consist mainly of cash, accounts receivable from the sale
          of oil and gas production and accounts payable.

     o    The number of shares of Pioneer common stock to be issued to the
          limited partners of each partnership upon the merger of the
          partnership will be determined by dividing 75% of the merger value
          assigned to the partnership by the value of one share of Pioneer
          common stock determined as described below. For purposes of example in
          this document, a share of Pioneer common stock has been valued at an
          assumed average closing price of $18.00. However, on the closing date
          of the merger of each partnership, the value of a share of Pioneer
          common stock will be recalculated by computing the average closing
          price of the Pioneer common stock, as reported by the New York Stock
          Exchange, for the ten trading days ending three business days before
          the date of the special meeting for each partnership. This
          recalculated value, and not the assumed average closing price of
          $18.00 per share of Pioneer common stock, used for illustration
          purposes in this document and on each limited partner's voting form,
          will be used to determine the actual number of shares of Pioneer
          common stock to be issued in the merger of each partnership. The
          recalculated value may be more or less than the assumed average
          closing price of $18.00 per share of Pioneer common stock. Pioneer may
          abandon the proposed merger of any or all of the partnerships if an
          event occurs that causes or results in a material adverse effect,
          among other things, on the price of Pioneer common stock, on the
          market prices for oil and gas generally or on the oil and gas industry
          generally.

     Distributions. No cash distributions will be made by any partnership to its
partners after the distribution in March 2001 through the closing date or
termination date of the merger of the partnership. The Pioneer common stock and
the cash payment to be distributed as payment of the merger value of each
participating partnership already reflect the expected amount of those
distributions. However, any cash distributions by a nonparticipating partnership
which would have been paid during that time period in the ordinary course of
that partnership's business will be distributed to its partners at about the
same time that the certificates representing Pioneer common stock and checks are
mailed to the partners of each participating partnership.

     Liabilities. Pioneer USA will assume all of the liabilities, including
contingent liabilities and obligations, of each participating partnership as of
the closing date of the merger of the partnership. As of the date of this
document, Pioneer USA is not aware of any material contingent liabilities to
which any partnership is subject.

     Expenses. We have not reduced the merger value for any partnership for
expenses of the transaction. Pioneer will pay those expenses.

ALLOCATION OF MERGER VALUE FOR EACH PARTNERSHIP AMONG PARTNERS OF THE
PARTNERSHIP

     In determining the portion of the merger value attributable to each $1,000
of initial limited partner investment in a partnership, Pioneer determined the
amount payable per $1,000 investment as if the assets of the partnership had
been sold on March 31, 2001 for cash equal to the merger value of the
partnership and the proceeds distributed in accordance with the liquidation
provisions of the partnership's partnership agreement. The limited partners of
each participating partnership would receive the same amounts if the merger
value of the partnership was allocated among the partners based on the
revenue-sharing provisions of the partnership agreement except for each of the
following partnerships which will receive more proceeds under the liquidation
provisions of its respective partnership agreement due to certain
prospect-by-prospect payout provisions not being met:

                  Parker & Parsley 81-I, Ltd.
                  Parker & Parsley 81-II, Ltd.
                  Parker & Parsley 82-I, Ltd.
                  Parker & Parsley 82-II, Ltd.
                  Parker & Parsley 82-III, Ltd.



                                      -40-
   50

OTHER METHODS OF DETERMINING MERGER VALUES

     Pioneer and Pioneer USA believe that the method used to determine the
merger value for each partnership is a fair and reasonable method of valuing the
partnership's properties. Pioneer and Pioneer USA considered a number of
alternative methods of determining the merger value for each partnership before
selecting a method. However, the selected method might not accurately reflect
the value of each partnership's assets. See "Risk Factors -- Risk Factors
Relating to the Merger of Each Partnership -- The Merger Values Involve
Estimates that Will Not Be Adjusted" on page 17. The following alternative
methods for determining the merger value for each partnership should be taken
into account in assessing the adequacy of the selected method.

     Book Value of Assets. Pioneer and Pioneer USA did not base the calculation
of merger value for each partnership on the net book value of the partnership's
assets. The net book value of each partnership's assets are based upon the
financial statements reported in accordance with generally accepted accounting
principles. The net book value is not adjusted for estimates in changes in the
fair market value of the assets. For this reason, Pioneer and Pioneer USA
believe that the merger value for each partnership is more indicative of the
fair market value of the assets of each partnership than the net book value of
the partnership's assets. See the supplemental information table on the second
page of the supplement for each partnership for the partnership's merger value
and its book value, in each case per $1,000 limited partner investment. In all
cases except Parker & Parsley 81-II, Ltd., the merger value is higher than the
book value. For Parker & Parsley 81-II, Ltd., the merger value is lower than
book value because of the long-lived nature of the oil and gas properties owned
by Parker & Parsley 81-II, Ltd. The merger value of Parker & Parsley 81-II, Ltd.
takes into account the discounting effect of owning long-lived oil and gas
reserves that is not reflected in a book value computation for the partnership.
Nonetheless, Pioneer USA has determined that the merger transaction is fair to
the limited partners of Parker & Parsley 81-II, Ltd. for the reasons noted
above.

     Trading Price of Units. None of the partnership interests are traded on a
national stock exchange or in any other significant market. Although some
partnership interests are occasionally sold in private or an informal secondary
market for limited partner securities, Pioneer and Pioneer USA believe any
market for the partnership interests is not reliable as an indicator of value
because any such market is highly illiquid and generally reflects an illiquidity
discount. As a result, Pioneer and Pioneer USA did not base the calculation of
the merger value for any partnership on recent trading prices of partnership
interests in the partnership. See Table 15 of Appendix A for historical
information about recent trades of partnership interests in each partnership.

     Repurchase Offers. Pioneer and Pioneer USA did not base the calculation of
the merger value for any partnership on the price of recent repurchase offers in
the partnership. Most partnerships do not have a repurchase offer obligation, so
no repurchase price information was available for those partnerships. Of the
partnerships with a repurchase offer obligation, the most recent repurchase
offers will be based on December 31, 2000 oil and gas prices. The merger value
for each partnership with repurchase offer obligations is lower than the 2001
repurchase offer price for the partnership because the repurchase price was
based on NYMEX oil and gas prices as of December 31, 2000, which were $26.69 per
Bbl of oil and $9.95 per Mcf of gas. Pioneer and Pioneer USA believe that the
repurchase obligation is not an indicator of fair value because it is calculated
annually on December 31 using oil and gas prices for that specific day. The
value determined under the repurchase obligation does not adequately reflect
future demand and supply fundamentals which have historically resulted in
significant volatility to oil and gas prices. See "Risk Factors -- Risk Factors
Relating to the Merger of Each Partnership -- Repurchase Rights Terminate on
Completion of the Mergers" on page 18 of this document and Table 8 of Appendix A
to this document for information on each partnership with repurchase offer
obligations.

     Timing of Pricing. Oil and gas prices have recovered from NYMEX oil and gas
prices of $12.00 per Bbl of oil and $2.00 per Mcf of gas as of December 31,
1998, to the five-year NYMEX futures prices for oil and gas as of March 30,
2001, set forth in the table on page 6 of this document. Pioneer and Pioneer USA
used those recovered oil and gas prices to calculate the merger value for each
partnership. Future oil and gas prices could be higher or lower than the prices
on March 30, 2001 which were used in calculating the merger value for each
partnership. Significant increases in future prices would increase cash
available for distribution from each partnership and could, in retrospect,
suggest that the merger value for such partnership was low by comparison. If
those current prices were to continue to prevail in the future, the merger value
for each partnership would appear low by comparison. In contrast, however, if
those current prices decline in the future, the merger value for each
partnership would appear high by comparison.

INFORMATION SOURCES

     Pioneer and Pioneer USA used the records of Pioneer USA and each
partnership to derive the information regarding:

     o    the ownership interests;

     o    prices being received or contracted for;



                                      -41-
   51

     o    costs;

     o    production;

     o    allocation of revenues and costs between classes of partners of each
          partnership;

     o    capital accounts of partners of each partnership; and

     o    other factual data used by Pioneer and Pioneer USA:

          -    to prepare the estimate of proved reserves for each partnership;

          -    to compute the merger value for each partnership; and

          -    to determine the allocation among partners of each partnership of
               the Pioneer common stock and cash to be received.

     While Pioneer and Pioneer USA have implemented procedures designed to
verify some of this information, the nature and volume of data preclude
verification of all information. In addition, information relating to prices,
costs and production history frequently is estimated based on incomplete data
and is subject to varying interpretations. Likewise, the provisions of some of
the partnership agreements are subject to different interpretations. In
allocating the merger value assigned to a partnership among its partners,
Pioneer and Pioneer USA attempted to apply a reasonable interpretation of those
provisions.



                                      -42-
   52

                         THE MERGER OF EACH PARTNERSHIP

GENERAL

     Immediately before the effective time of the merger of each participating
partnership, the partnership agreement for the partnership will be amended by
the merger amendment to permit the merger of the partnership with and into us.
At the effective time of the merger of each participating partnership, the
partnership will be merged with and into us. We will be the surviving entity. In
addition, at the effective time of the merger of each participating partnership,
each of your partnership interests in the partnership will be converted into the
right to receive Pioneer common stock and cash.

LEGAL OPINION FOR LIMITED PARTNERS

     Each of the partnership agreements, except the partnership agreement for
Parker & Parsley Producing Properties 88-A, L.P., requires that special legal
counsel render an opinion on behalf of the limited partners of each partnership
to Pioneer USA that neither the grant nor the exercise of the right to approve
the merger of the partnership by its limited partners will adversely affect the
federal income tax classification of the partnership or any of its limited
partners. In addition, the partnership agreement for each of the following
partnerships requires an opinion that neither the grant nor exercise of such
right will result in the loss of any limited partner's limited liability:


                                                          
     Parker & Parsley 81-1, Ltd.                             Parker & Parsley Selected 85 Private Investment, Ltd.
     Parker & Parsley 81-II, Ltd.                            Parker & Parsley 86-A, Ltd.
     Parker & Parsley 82-I, Ltd.                             Parker & Parsley 86-B, Ltd.
     Parker & Parsley 82-II, Ltd.                            Parker & Parsley 86-C, Ltd.
     Parker & Parsley 82-III, Ltd.                           Parker & Parsley Private Investment 86, Ltd.
     Parker & Parsley 83-A, Ltd.                             Parker & Parsley 87-A Conv., Ltd.
     Parker & Parsley 83-B, Ltd.                             Parker & Parsley 87-A, Ltd.
     Parker & Parsley 84-A, Ltd.                             Parker & Parsley 87-B, Ltd.
     Parker & Parsley 85-A, Ltd.                             Parker & Parsley Producing Properties 87-A, Ltd.
     Parker & Parsley 85-B, Ltd.                             Parker & Parsley Producing Properties 87-B, Ltd.
     Parker & Parsley Private Investment 85-A, Ltd.


     For each of the partnerships, other than those listed below, the counsel
designated to render the opinion described above must be counsel other than
counsel to Pioneer USA or any partnership:


                                                          
     Parker & Parsley 88-A Conv., L.P.                       Parker & Parsley 90-A Conv., L.P.
     Parker & Parsley 88-A, L.P.                             Parker & Parsley 90-A, L.P.
     Parker & Parsley 88-B Conv., L.P.                       Parker & Parsley 90-B Conv., L.P.
     Parker & Parsley 88-B, L.P.                             Parker & Parsley 90-B, L.P.
     Parker & Parsley 88-C Conv., L.P.                       Parker & Parsley 90-C Conv., L.P.
     Parker & Parsley 88-C, L.P.                             Parker & Parsley 90-C, L.P.
     Parker & Parsley Private Investment 88, L.P.            Parker & Parsley Private Investment 90, L.P.
     Parker & Parsley 89-A Conv., L.P.                       Parker & Parsley 90 Spraberry Private Dev., L.P.
     Parker & Parsley 89-A, L.P.                             Parker & Parsley 91-A, L.P.
     Parker & Parsley 89-B Conv., L.P.                       Parker & Parsley 91-B, L.P.
     Parker & Parsley 89-B, L.P.
     Parker & Parsley Private Investment 89, L.P.


     In all cases, the designated counsel and the legal opinion must be approved
by the limited partners of each partnership.

     In all cases, Pioneer USA has retained            of Dallas, Texas for the
purpose of rendering the legal opinions described above on behalf of the limited
partners of each partnership to Pioneer USA.       is not affiliated to Pioneer,
Pioneer USA or any of the partnerships. The merger proposals for each
partnership include an approval of that counsel and the form of its opinion. See
"The Special Meetings -- Time and Place; Purpose" on page 55 of this document. A
copy of the opinion is attached as an exhibit to the merger proposals for each
partnership.



                                      -43-
   53

DISTRIBUTION OF PIONEER COMMON STOCK AND CASH PAYMENT

     Upon completion of the merger of each participating partnership, the
partners of the partnership will have no continuing interest in, or rights as
partners of, the partnership. The transfer books of each participating
partnership will be closed on the closing date of the merger of the partnership.
All partnership interests in each participating partnership will cease to be
outstanding, will automatically be cancelled and retired, and will cease to
exist. The certificates previously representing partnership interests in each
participating partnership held by record partners will represent only the right
to receive Pioneer common stock and cash.

     We intend to mail certificates representing Pioneer common stock and checks
to the partners of record of each participating partnership promptly following
the effectiveness of the merger of the partnership in payment of the merger
value for the partnership. Partners of each participating partnership will not
be required to surrender partnership interest certificates to receive the
Pioneer common stock and the cash payment.

FRACTIONAL SHARES

     Pioneer will not issue fractional shares to any limited partner upon
completion of the merger of any partnership. For each fractional share that
would otherwise be issued, Pioneer will round any fractional shares of Pioneer
common stock up to the nearest whole share and will reduce the cash payment to a
limited partner of a participating partnership by the amount rounded up based on
the average closing price per share used in determining the number of shares of
Pioneer common stock to be offered.

MATERIAL U.S. FEDERAL INCOME TAX CONSEQUENCES

     The following discussion summarizes the material federal income tax
consequences of a conversion of partnership interests into Pioneer common stock
and cash pursuant to the merger of each participating partnership. The federal
tax consequences of each merger will vary for each limited partner because of
the different circumstances of each participating partnership and the individual
federal income tax position of each limited partner.

     The following discussion is based upon current law. Future legislative,
judicial or administrative changes or interpretations could alter or modify the
following statements and conclusions, and any of these changes or
interpretations could be retroactive and could affect the tax consequences to
the limited partners of each partnership.

     The following discussion is not exhaustive of all possible tax
consequences. It does not address any state, local or foreign tax consequences,
nor does it discuss all of the aspects of federal income taxation that may be
relevant to specific partners in light of their particular circumstances. The
discussion below describes material federal income tax consequences applicable
to individuals who are citizens or residents of the United States, and therefore
has limited application to domestic corporations and persons subject to
specialized federal income tax treatment, such as foreign persons, tax-exempt
entities, regulated investment companies and insurance companies.

     THE FOLLOWING DISCUSSION DOES NOT ADDRESS THE PARTICULAR FACTS AND
CIRCUMSTANCES OF ANY PARTICULAR LIMITED PARTNER. YOU ARE ADVISED TO CONSULT YOUR
OWN TAX ADVISOR TO DETERMINE ALL OF THE RELEVANT FEDERAL, STATE AND LOCAL TAX
CONSEQUENCES OF EACH MERGER TO YOU.

Tax Consequences of a Conversion of Partnership Interests.

     o Generally. As more fully described below, if you own partnership
interests in a participating partnership, you will generally recognize an
aggregate amount of net gain or loss equal to the difference between (1) the sum
of the amount of cash and the fair market value of Pioneer common stock you
receive in the merger of that partnership and (2) your adjusted tax basis in
your partnership interests exclusive of any basis attributable to liabilities of
the partnership immediately prior to the merger. That net gain or loss may be
comprised of ordinary income or ordinary loss depending upon the extent of any
recapture of depletion or intangible drilling and development costs and any
appreciation or depreciation in the ordinary assets of the partnership. The
recognition of ordinary income will decrease the capital gain component or
increase the capital loss component of the net gain or loss otherwise
recognizable as a consequence of the merger.

     o Characterization of the Merger of Each Partnership. The merger of a
participating partnership into Pioneer USA should be treated for federal income
tax purposes as a sale by such partnership of its assets for Pioneer common
stock and cash followed by a distribution of the Pioneer common stock and cash
received in liquidation of the limited partnership interests. Under Section 613A
of the Internal Revenue Code, each of the partners of such partnership must:

          -    maintain the partner's share of the basis in the partnership's
               oil and gas properties at the partner level;

          -    adjust such basis for depletion deductions; and



                                      -44-
   54

          -    use such basis to calculate gain or loss at the partner level on
               any sale by the partnership of its oil and gas properties.

     Accordingly, each of the mergers should be generally treated for tax
computation purposes as:

          -    a taxable sale by you of your interest in a participating
               partnership's oil and gas properties for Pioneer common stock and
               cash and the assumption of liabilities; and

          -    a taxable sale of any remaining partnership assets by the
               participating partnership for Pioneer common stock and cash
               followed by a liquidation of the participating partnership.

     o Gain or Loss on Sale of Partnership Oil and Gas Properties. Upon the
deemed sale of a partnership's oil and gas properties in the merger of the
partnership, you will recognize gain or loss equal to the difference between:

          -    the portion of the partnership's "amount realized" on the sale of
               its oil and gas properties allocated to you; and

          -    your adjusted tax basis in the partnership oil and gas properties
               sold, which must be reduced to reflect depletion claimed during
               the current year in respect of production prior to the date of
               the merger.

     The amount realized will include the amount of cash and the fair market
value of Pioneer common stock received and the amount of any liability assumed
by Pioneer USA in connection with the merger of the partnership which is
attributable to the partnership's oil and gas properties. If gain is recognized
on such sale, the portion of the gain that is treated as recapture of intangible
drilling and development costs or depletion will be treated as ordinary income.
See "Recapture of Intangible Drilling and Development Costs" and "Recapture of
Depletion" below. The remainder of such gain generally will constitute "Section
1231 gain." If loss is recognized on such sale, such loss generally will
constitute "Section 1231 loss." See "Section 1231 Gains and Losses" below. You
must take into account your share of the portion of the gain that constitutes
recapture income, if any, as ordinary income and must aggregate your share of
the Section 1231 gains and losses along with the Section 1231 gains and losses
you realize from other sources.

     o Other Gain or Loss. You will also recognize your allocable share of the
partnership's gain or loss, if any, on the deemed sale of its assets other than
oil and gas properties. Such gain or loss will be equal to the difference
between the amount realized by the partnership on the sale of such assets and
the partnership's adjusted tax basis in such assets. Such gain or loss will be
capital or ordinary depending on the nature of the assets sold.

     Finally, in the event that the amount of cash and the fair market value of
Pioneer common stock you receive in the merger of the partnership is more or
less than the adjusted tax basis in your partnership interests, as adjusted to
reflect gains and losses described in the two preceding paragraphs as well as
the effects of the partnership's current year activities, then upon the deemed
liquidation of a partnership, you will recognize capital gain or loss equal to
the difference between such amounts. See "Tax Consequences of Partnership
Operations" below.

     You will be provided with information necessary to make the calculations
described above for purposes of filing your own federal income tax return. In
order to simplify your federal income tax reporting, this information will
include a calculation of the amount and character of your gain on the deemed
sale of the partnership's oil and gas properties based upon our estimates. You
should verify the accuracy of these calculations based upon your own records.

     o Section 1231 Gains and Losses. Generally, if the total amount of the
Section 1231 gains exceeds the total amount of Section 1231 losses, all such
gains and losses will be treated as capital gains and losses, and if the total
amount of the Section 1231 losses exceeds the total amount of the gains, all
such gains and losses will be treated as ordinary income and losses. However,
your net Section 1231 gains will be treated as ordinary income to the extent of
your net Section 1231 losses during the immediately preceding five years,
reduced by any amount of net Section 1231 losses that have been previously
"recaptured" by you pursuant to this rule.

     o Recapture of Intangible Drilling and Development Costs. Generally, all or
a portion of the amounts previously deducted for intangible drilling and
development costs for a property must be recaptured upon the disposition of such
property by treating the gain, if any, realized on such disposition as ordinary
income to the extent of such amounts. For a property placed in service prior to
1987, the potential recapture amount is equal to the excess of the aggregate
amounts previously deducted for intangible drilling and development costs for
such property over the amount by which the deduction for depletion for such
property would have been increased had the intangible drilling and development
costs been capitalized and recovered through depletion rather than deducted in
the year incurred. It should be noted that, if percentage depletion, rather than
cost depletion, has been claimed for such property, the hypothetical
capitalization of intangible drilling and development costs may result in little
or no increase in depletion deductions and, as a consequence, most or all of the
intangible drilling and development costs for such



                                      -45-
   55

property may be subject to recapture. For property placed in service during 1987
or thereafter, the full amount of intangible drilling and development costs
previously deducted, unreduced by depletion, is subject to recapture to the
extent of any gain.

     o Recapture of Depletion. Upon the disposition of a property that was
placed in service during 1987 or thereafter, all amounts previously deducted for
depletion, whether cost depletion or percentage depletion, to the extent such
amounts reduced the basis in the property, must be recaptured by treating the
gain, if any, recognized on such disposition as ordinary income to the extent of
such amounts. No such recapture rule is applicable to a property placed in
service before 1987.

     o Tax Rates. The capital gains rate for individuals and other non-corporate
taxpayers is 20% if the capital asset has been held for more than one year at
the time of consummation of the merger of each partnership. Corporate taxpayers
are taxed at a maximum marginal rate of 35% for both capital gains and ordinary
income. The maximum marginal federal income tax rate for ordinary income of
individuals and other non-corporate taxpayers is 39.6%. Capital losses are
deductible only to the extent of capital gains, except that, subject to the
passive activity loss limitation discussed below, non-corporate taxpayers may
deduct up to $3,000 of capital losses in excess of the amount of their capital
gains against ordinary income. Excess capital losses generally can be carried
forward to succeeding years. A corporation is permitted to carry back excess
capital losses to the three preceding years, provided the carryback does not
increase or produce a net operating loss for any of those years. A corporation's
carryforward period is five years and a non-corporate taxpayer can carry such
losses forward indefinitely.

     o Passive Activity Loss Limitation. Under Section 469 of the Internal
Revenue Code, any losses from any participating partnership that have been
suspended under the passive loss rules will become fully deductible as a result
of the merger of any such partnership.

FIRPTA Withholding. Gain recognized by a foreign limited partner on the sale by
a participating partnership which is effectively connected with the conduct of a
U.S. trade or business of its assets pursuant to the merger of the partnership
will be subject to federal income tax. Gain realized on the sale of U.S. real
property, including a participating partnership's oil and gas properties, is
treated as effectively connected with the conduct of a U.S. trade or business
for this purpose. Under Internal Revenue Code Section 1446, a participating
partnership in which an interest is held by a foreign person generally is
required to deduct and withhold a tax equal to the highest marginal federal
income tax rate applicable to the partner multiplied by such partner's allocable
share of effectively connected income. In order to comply with this requirement,
each participating partnership will withhold the prescribed percentage of the
effectively connected income allocated to you unless you properly complete and
sign a certification of non-foreign status certifying your taxpayer
identification number and address, and that you are not a foreign person.
Amounts withheld will be creditable against a limited partner's federal income
tax liability and, if in excess thereof, a refund may be obtained from the
Internal Revenue Service by filing a U.S. income tax return.

Tax Consequences of Partnership Operations. The federal income tax consequences
of the merger of each partnership, described above, are in addition to the tax
consequences of a participating partnership for the taxable year ending on the
closing date of the merger of the partnership. You must include your allocable
share of a participating partnership's items of income, gain, loss, deduction
and credit for that taxable year, including your allocable share through the
closing date of the merger of the partnership, on your federal income tax return
for that taxable year. That information will be provided to you on a Schedule
K-1 as required by tax law. The results of partnership operations for such
period will impact your tax basis in a participating partnership, and your
computation of gain or loss resulting from the merger of the partnership.

ACCOUNTING TREATMENT

     The merger of each participating partnership will be accounted for as a
purchase under generally accepted accounting principles. Under those rules,
Pioneer USA will record the assets and liabilities of each participating
partnership on its books at its estimated fair market value.

EFFECT OF MERGER OF EACH PARTNERSHIP ON LIMITED PARTNERS WHO DO NOT VOTE IN
FAVOR OF THE MERGER; NO APPRAISAL OR DISSENTERS' RIGHTS

     You will be bound by the merger of each partnership in which you own an
interest if the limited partners in the partnership vote a majority, or 66 2/3%
for Parker & Parsley 91-A, L.P. and Parker & Parsley 91-B, L.P., of their
partnership interests in favor of the merger, even if you vote against the
merger or do not vote. If the merger of the partnership occurs, you will be
entitled to receive only an amount of cash and Pioneer common stock based on the
merger value of your partnership interests in the partnership. Under the laws of
the State of Delaware and the State of Texas, which are the states of formation
of the partnerships, you are not entitled to appraisal or dissenters' rights
with respect to the merger of any partnership.



                                      -46-
   56

FUTURE OF NONPARTICIPATING PARTNERSHIPS

     If the limited partners of a partnership do not approve the merger of that
partnership, the partnership will remain in existence. Each nonparticipating
partnership will continue to operate as a separate legal entity with its own
assets and liabilities. There will be no immediate change in its business
objectives, and Pioneer USA plans to continue to manage and operate each
nonparticipating partnership in accordance with the terms of its current
partnership agreement. A limited partner in a nonparticipating partnership will
retain the rights, privileges and obligations that the limited partner currently
has pursuant to the partnership agreement of the nonparticipating partnership.
At about the same time that Pioneer USA mails certificates for Pioneer common
stock and checks for the cash payment to the partners of each participating
partnership in payment of the merger value for the partnership, Pioneer USA will
mail any cash distributions that were delayed for administrative purposes prior
to the completion of the merger of each participating partnership to the
partners of each nonparticipating partnership.

     Pioneer USA's board of directors will determine each nonparticipating
partnership's business plan. In addition, the board of directors of each of
Pioneer and Pioneer USA will decide what, if any, actions they will take with
respect to each nonparticipating partnership. Potential activities may include a
tender offer for partnership interests of limited partners or a proposal to
acquire the assets of, or merge with, one or more of the nonparticipating
partnerships. Such proposals may be on terms similar to or different from those
of the merger of each partnership described in this document.

     Pioneer USA plans to continue to manage each nonparticipating partnership
until such partnership is dissolved or Pioneer USA is replaced as the general
partner of such partnership. The replacement of Pioneer USA as general partner
would require compliance with the partnership agreement of such nonparticipating
partnership, including the requisite vote of the limited partners thereof. A
nonparticipating partnership may be dissolved in the future in accordance with
its partnership agreement if Pioneer USA or any substituted general partner
withdraws from the nonparticipating partnership, or in some cases, otherwise
elects to dissolve that partnership. Pioneer USA might withdraw from, or
otherwise elect to dissolve, a nonparticipating partnership if Pioneer USA
determines that the nonparticipating partnership's continued operation is
uneconomical or its dissolution and liquidation are in the best interests of the
partners of that partnership. Upon dissolution, the nonparticipating
partnership's assets may be sold for cash or securities, which may be more or
less than the merger value assigned to that partnership, or distributed in kind
to the partners of the nonparticipating partnership. Any such sale may be to
Pioneer or an affiliate of Pioneer and may involve cash or securities of
Pioneer.

NONMANAGING GENERAL PARTNERS OF SOME PARTNERSHIPS

     Eight of the partnerships described in this document have two general
partners. In those eight partnerships, Pioneer USA is the managing general
partner. The second general partner in those partnerships is a parallel
partnership whose limited partners are former affiliates of Pioneer's
predecessors. The names of the eight partnerships and the names of the
nonmanaging general partner in each of those partnerships are:



             PARTNERSHIP                           NONMANAGING GENERAL PARTNER
             -----------                           ---------------------------
                                          
     Parker & Parsley 81-I, Ltd.             Parker & Parsley Employees 81-I, Ltd.
     Parker & Parsley 81-II, Ltd.            Parker & Parsley Employees 81-II, Ltd.
     Parker & Parsley 82-I, Ltd.             Parker & Parsley Employees 82-I, Ltd.
     Parker & Parsley 82-II, Ltd.            Parker & Parsley Employees 82-II, Ltd.
     Parker & Parsley 82-III, Ltd.           Parker & Parsley Employees 82-III, Ltd.
     Parker & Parsley 83-A, Ltd.             Parker & Parsley Employees 83-A, Ltd.
     Parker & Parsley 83-B, Ltd.             Parker & Parsley Employees 83-B, Ltd.
     Parker & Parsley 84-A, Ltd.             Parker & Parsley Employees 84-A, Ltd.


     Pioneer USA is the sole general partner of each of the nonmanaging general
partners. In that capacity, Pioneer USA has authority:

     o    to cause the nonmanaging general partner to perform its obligations
          relating to the partnership described above; and

     o    to exercise on behalf of the nonmanaging general partner all of the
          rights and elections granted to the nonmanaging general partner by the
          partnership described above.

     None of the nonmanaging general partners has the right to vote on the
merger of any partnership. However, Pioneer USA, as the general partner of each
nonmanaging general partner, has approved the merger of each partnership and the
distribution of this document to the limited partners of each partnership and to
the unaffiliated limited partners of each nonmanaging general partner, if any,
of each partnership. The aggregate merger value attributable to the unaffiliated
limited partners of the nonmanaging general partners is $196,026, consisting of



                                      -47-
   57

approximately 8,168 shares of Pioneer common stock in the aggregate and a cash
payment of approximately $49,000 in the aggregate. Pioneer USA will not receive
any Pioneer common stock or cash in any merger for its partnership interests in
any nonmanaging general partner.

THIRD PARTY OFFERS

     Pioneer USA will consider offers from third parties to purchase any
partnership or its assets. Those who wish to make an offer for any partnership
or its assets must demonstrate to Pioneer USA's reasonable satisfaction their
financial ability and willingness to complete such a transaction. Before
reviewing non-public information about a partnership, a third party will need to
enter into a customary confidentiality agreement. Offers should be at prices and
on terms that are fair to the partners of the partnership for which the offer is
being made and more favorable to the unaffiliated limited partners than the
prices and terms proposed for the merger of that partnership in this document.
Pioneer reserves the right to match or top any such offer. Since first
announcing our willingness to consider third party offers in September 1999,
Pioneer USA has not received any third party offer for any partnership or its
assets. Persons desiring to make an offer for any partnership should contact
Timothy L. Dove or Mark L. Withrow, Board of Directors, Pioneer Natural
Resources USA, Inc., 1400 Williams Square West, 5205 North O'Connor Boulevard,
Irving, Texas 75039 by July 31, 2001.

MERGER AMENDMENT

     In order to complete the merger of each partnership, the partnership
agreement for the partnership requires an amendment to add a provision
permitting the merger of the partnership with and into Pioneer USA. See the
merger proposals, which include the merger amendment, set forth in Appendix D to
this document. At the special meeting for each partnership, the limited partners
of the partnership will vote upon the merger amendment, which, if approved, will
be effective immediately prior to the effectiveness of the merger of the
partnership.

TERMINATION OF REGISTRATION AND REPORTING REQUIREMENTS

     As a result of the merger of each participating partnership, the
partnership interests in the partnership, as well as the partnership itself,
will cease to exist. Twenty-five of the partnerships described in this document
have registered their partnership interests under, or are otherwise subject to
the informational requirements of, the Securities Exchange Act of 1934. See
"Where You Can Find More Information" for a list of those partnerships. Upon the
completion of the merger of each reporting partnership, Pioneer USA intends to
terminate:

     o    registration of the partnership interests of the partnership under the
          Securities Exchange Act of 1934; and

     o    the partnership's obligations to file reports and other information
          under the Securities Exchange Act of 1934.

     Pioneer USA plans to cause each nonparticipating partnership that is also a
reporting partnership to continue to file reports and other information under
the Securities Exchange Act of 1934. However, Pioneer USA's board of directors
could determine in the future to cause each such partnership to terminate its
reporting obligations as permitted by federal securities laws.

     The advantages of remaining registered, or remaining obligated to file
reports, under the Securities Exchange Act of 1934 include the informational and
reporting requirements under that act, including requirements related to tender
offers, proxy solicitation and consents and insiders' transactions in
partnership interests. Those reporting requirements may provide limited partners
with more detailed information on a more frequent basis than might otherwise be
required under the partnership agreement for the partnership. In addition, a
partnership's filings under the Securities Exchange Act of 1934 are available to
the public over the Internet at the SEC's web site at http://www.sec.gov and are
also available at the SEC's public reference rooms in Washington, D.C., New
York, New York and Chicago, Illinois.

     The disadvantages of remaining registered, or remaining obligated to file
reports, include the partnership's cost to prepare and distribute the various
reports and other information required under the Securities Exchange Act of
1934. Deregistering the partnership interests of a nonparticipating partnership
or otherwise terminating its filing and reporting obligations could reduce that
partnership's general and administrative expenses because the reporting
obligations of the partnership under its partnership agreement require annual
and semi-annual reports, but not quarterly reports.

ELIMINATION OF A FAIRNESS OPINION REQUIREMENT THAT WOULD OTHERWISE BENEFIT
PIONEER USA

     Pioneer USA, as the sole general partner of each of Parker & Parsley 91-A,
L.P. and Parker & Parsley 91-B, L.P., is entitled to receive an opinion as to
the fairness of the proposed merger transaction to Pioneer USA in its capacity
as sole general partner of each of those partnerships. However, since Pioneer
and Pioneer USA are the parties making the offer for the proposed merger
transaction, Pioneer USA will not seek such fairness opinion. In



                                      -48-
   58

addition, Pioneer USA, as the sole general partner of each of those two
partnerships, is entitled to amend, and Pioneer USA will amend, the partnership
agreement for the partnership to eliminate the requirement for such fairness
opinion for Pioneer USA in connection with the proposed merger of the
partnership.

SOURCE OF FUNDS

     Pioneer USA will need approximately $27.5 million in the aggregate to
complete the mergers for all of the partnerships. Pioneer USA will borrow that
amount from Pioneer as an intercompany loan. Pioneer USA plans to repay that
intercompany loan with cash flows from operations. Immediately after completion
of the merger of each participating partnership, the cash portion of the working
capital in the partnership will be used to repay a portion of the intercompany
loan. There are no material conditions to the intercompany loan other than it is
conditioned upon the occurrence of the proposed merger transaction. Pioneer USA
does not have any alternative financing arrangements or financing plans in the
event such intercompany loan falls through.

     Pioneer, in turn, will obtain such funds from its credit facility agreement
with a syndicate of banks, including Bank of America, N.A. and Credit Suisse
First Boston. Pioneer plans to repay amounts borrowed under its credit facility
with cash flows from operations. As of December 31, 2000, the outstanding
borrowings due under Pioneer's credit facility were $225.0 million, and the
borrowing capacity available under Pioneer's credit facility was $575.0 million.
Such borrowings bear interest, at Pioneer's option, based on:

     o    a base rate equal to the eurodollar margin then in effect (125 basis
          points as of December 31, 2000) less 125 basis points plus the higher
          of (1) the prime rate of Bank of America, N.A., which was 9.50% at
          December 31, 2000, or (2) a rate per annum based on the weighted
          average of the rates on overnight federal funds transactions with
          members of the Federal Reserve System (6.50% at December 31, 2000),
          plus 50 basis points;

     o    a eurodollar rate, substantially equal to the London Interbank Offered
          Rate, or LIBOR, plus the eurodollar margin then in effect based on a
          grid of Pioneer's debt ratings and its total leverage ratio, which is
          the ratio of Pioneer's total debt to earnings before gain or loss on
          the disposition of assets, interest expense, depreciation, depletion
          and amortization expense, income taxes, exploration expense and other
          noncash expenses; or

     o    for aggregate advances not exceeding $50 million, a fixed rate as
          quoted by the lending banks at Pioneer's request.

     Eurodollar rate borrowings under Pioneer's credit facility have periodic
maturities, at Pioneer's option, of one, two, three, six, nine or 12 months.
Pioneer's obligations under its credit facility are secured by a guaranty of
certain United States subsidiaries of Pioneer and a pledge of a portion of the
capital stock of foreign subsidiaries of Pioneer. For purposes of its credit
facility those subsidiaries have been designated by Pioneer as restricted
subsidiaries.

     The terms of Pioneer's credit facility also contain various restrictive
covenants and compliance requirements, which include:

     o    limits on the incurrence of additional indebtedness;

     o    restrictions as to merger, sale or transfer of assets without the
          banks' prior consent; and

     o    the maintenance of leverage ratios.

For example, Pioneer must maintain (1) a total leverage ratio not to exceed 4.00
to 1.00 through September 30, 2002, and 3.75 to 1.00 thereafter, (2) an annual
ratio of the net present value of Pioneer's oil and gas properties to total debt
of at least 1.25 to 1.00, (3) limitations on Pioneer's total debt and (4)
restrictions on some types of payments.



                                      -49-
   59

PAYMENT OF EXPENSES AND FEES

     Pioneer will pay all expenses and fees of the merger of each partnership
even if the merger of the partnership is not completed. Pioneer estimates that
its aggregate expenses will be as follows:


                                                                              
          Filing fee with SEC ..............................................     $     20,500
          Legal fees .......................................................          350,000
          Accounting fees ..................................................           50,000
          Financial advisor fees ...........................................          350,000
          Independent petroleum consultant fees ............................           25,000
          Printing and mailing fees ........................................          900,000
          Information agent fees and solicitation and tabulation expenses ..          225,000
          Miscellaneous ....................................................           12,300
                                                                                 ------------
              Total expenses ...............................................     $  1,932,800
                                                                                 ============




                                      -50-
   60

                              THE MERGER AGREEMENT

     The following describes the material terms of the merger agreement. Pioneer
and Pioneer USA expect to sign the merger agreement after the Securities and
Exchange Commission clears this document for mailing to the limited partners of
each partnership. The full text of the form of the merger agreement is attached
as Appendix E to this document and is incorporated by reference in this
document. We encourage you to read the entire merger agreement.

STRUCTURE; EFFECTIVE TIME

     The merger agreement provides for the merger of each participating
partnership with and into Pioneer USA, with Pioneer USA surviving each merger.
Each merger will become effective at the time of the filing of the certificate
of merger for each participating partnership with the Secretary of State of the
State of Delaware and, for each participating partnership formed in Texas, with
the Secretary of State of the State of Texas. Each certificate of merger is
expected to be filed as soon as practicable after the last condition precedent
to the related merger set forth in the merger agreement has been satisfied or
waived. We estimate that the closing of the merger of each partnership will be
in July 2001.

EFFECTS OF THE MERGERS

     As a result of the merger of each participating partnership, the partners
in the partnership will have no continuing interest in that partnership.
Following the merger of each participating partnership, there will be no trading
market for the partnership interests in, and no further distributions paid to
the former partners of, the partnership. In addition, following the consummation
of the merger of each participating partnership that is also a reporting
partnership, the registration of any partnership interests in the partnership
under the Securities Exchange Act of 1934 will be terminated.

CONDUCT OF BUSINESS PRIOR TO THE MERGERS

     From the date of the merger agreement until the effective time of the
merger of each partnership, each partnership is required:

     o    to conduct its business only in the ordinary course consistent with
          past practice; and

     o    to use its reasonable best efforts:

          -    to preserve intact its business organization;

          -    to keep available the services of its officers, employees and
               consultants; and

          -    to preserve its relationships with customers, suppliers and other
               persons with which it has significant business dealings.

     Pioneer USA has suspended cash distributions to the partners of each
partnership until after the effective time of the merger of the partnership.
Partners of each nonparticipating partnership will receive cash distributions
that are delayed for administrative purposes at the same time Pioneer USA mails
certificates for Pioneer common stock and checks to the partners of each
participating partnership in payment of merger value for each partnership.

OTHER AGREEMENTS

     Special Meetings; Proxies. Pioneer USA has agreed to cause the special
meeting of the limited partners of each partnership to be duly called and held
as soon as reasonably practicable for the purpose of voting on the approval and
adoption of the merger proposals for the partnership. Pioneer USA has also
agreed to use its reasonable best efforts to solicit from the limited partners
of each partnership proxies in favor of the merger proposals and to take all
other action necessary or advisable to secure any vote or consent of the limited
partners of the partnership required by the partnership agreement of the
partnership or the merger agreement or by law in connection with the merger of
the partnership.

     Reasonable Commercial Efforts. Each party has agreed to use all reasonable
commercial efforts:

     o    to obtain in a timely manner all necessary waivers, consents and
          approvals and to effect all necessary registrations and filings; and

     o    to take, or cause to be taken, all actions and to do, or cause to be
          done, all things necessary, proper or advisable under applicable laws
          and regulations to consummate as promptly as practicable the
          transactions contemplated by the merger agreement.



                                      -51-
   61

REPRESENTATIONS AND WARRANTIES OF PIONEER, PIONEER USA AND EACH PARTNERSHIP

     The merger agreement contains substantially reciprocal representations and
warranties of Pioneer, Pioneer USA and each of the partnerships, including the
following matters:

     o    due organization or formation, standing, corporate or partnership
          power and qualification;

     o    absence of any conflict, breach, notice requirement or default under
          organizational documents and material agreements as a result of each
          contemplated merger;

     o    authority to enter into and the validity and enforceability of the
          merger agreement;

     o    absence of any material adverse change since March 31, 2001; and

     o    accuracy of information.

     In addition, the merger agreement contains representations and warranties
by:

     o    each of the partnerships as to capitalization;

     o    each of Pioneer and each reporting partnership, as to the absence in
          its reports filed with the SEC of any untrue statement of a material
          fact or any omission to state a material fact necessary to make the
          statements in such reports not misleading;

     o    each of Pioneer and each partnership, that its financial statements
          have been prepared in accordance with generally accepted accounting
          principles applied on a consistent basis and fairly present its
          financial condition and results of operations; and

     o    Pioneer USA as to its capacity as the managing or sole general partner
          of each partnership and as the sole general partner of each
          nonmanaging general partner.

CONDITIONS TO THE MERGER OF EACH PARTNERSHIP

     Conditions to the Obligations of Each Party. The obligations of Pioneer,
Pioneer USA and each partnership to complete the merger of the partnership are
dependent on the satisfaction of the following conditions:

     o    the merger agreement shall have been approved by the requisite vote of
          the limited partners of the partnership entitled to vote at the
          partnership's special meeting;

     o    Pioneer USA shall have received the fairness opinion from Stanger
          that, as of the date of that opinion, that the merger value for each
          partnership and the allocation of the merger value of the partnership
          (1) to the limited partners of the partnership as a group, (2) to the
          general partners of the partnership as a group, (3) to Pioneer USA as
          the managing or sole general partner of the partnership, (4) to the
          unaffiliated limited partners of the partnership as a group and (5) to
          the unaffiliated limited partners of the nonmanaging general partner,
          if any, of the partnership as a group, is fair to the unaffiliated
          limited partners of the partnership and the unaffiliated limited
          partners of the nonmanaging general partner, if any, of the
          partnership, from a financial point of view;

     o    Pioneer USA shall have received the opinion of counsel to the limited
          partners of each partnership that (1) neither the grant nor the
          exercise of the right to approve the merger of the partnership by its
          limited partners will adversely affect the federal income tax
          classification of the partnership or any of its limited partners and
          (2) neither the grant nor exercise of such right will result in the
          loss of any limited partner's limited liability;

     o    the absence of any law, regulation, judgment, injunction, order or
          decree that would prohibit the consummation of any merger;

     o    the absence of any pending suit, action or proceeding challenging the
          legality or any aspect of the merger of any partnership or the
          transactions related to the merger;

     o    the authorization for listing on the New York Stock Exchange and the
          Toronto Stock Exchange upon official issuance of notice shall have
          been received for the shares of Pioneer common stock to be issued upon
          the merger of each partnership;

     o    all material filings and registrations with, and notifications to,
          third parties shall have been made and all material approvals and
          consents of third parties shall have been received; and



                                      -52-
   62

     o    the absence of any opinion of counsel that the exercise by the limited
          partners of each partnership of the right to approve the merger of the
          partnership is not permitted by state law.

     Conditions to the Obligations of Pioneer. The obligations of Pioneer to
complete the merger of each partnership are further subject to the satisfaction
of the following conditions:

     o    each of Pioneer USA and each partnership having performed in all
          material respects its agreements contained in the merger agreement;
          and

     o    the representations and warranties of Pioneer USA and each partnership
          being true and correct in all material respects at the closing date of
          the merger of the partnership as if made at that time unless they
          relate to another specified time.

     Conditions to the Obligations of Pioneer USA and Each Partnership. The
obligations of Pioneer USA and each partnership to complete the merger of the
partnership are further subject to the satisfaction of the following conditions:

     o    Pioneer having performed in all material respects its agreements
          contained in the merger agreement; and

     o    the representations and warranties of Pioneer being true and correct
          in all material respects at the closing date of the merger of the
          partnership as if made at that time unless they relate to another
          specified time.

TERMINATION OF THE MERGER AGREEMENT AND THE MERGER OF ANY PARTNERSHIP

     The merger agreement may be terminated and the merger of any partnership
abandoned at any time prior to the effective time, whether before or after
approval by the limited partners:

     o    by the mutual written consent of the parties;

     o    by any party, if:

          -    any applicable law, rule or regulation makes consummation of any
               merger illegal or otherwise prohibited or any final and
               non-appealable judgment, injunction, order or decree enjoining
               any party from consummating any merger is entered;

          -    the requisite limited partner approval for a partnership is not
               obtained by a vote at the special meeting for the partnership or
               at any adjournment or postponement of the special meeting; or

          -    any suit, action or proceeding is filed against Pioneer, Pioneer
               USA, any partnership or any officer, director or affiliate of
               Pioneer or Pioneer USA challenging the legality or any aspect of
               the merger of any partnership or the transactions related to the
               merger;

     o    by Pioneer, if Pioneer USA or any partnership is in material breach of
          the merger agreement;

     o    by Pioneer USA or any partnership as to that partnership's merger, if
          Pioneer is in material breach of the merger agreement;

     o    by Pioneer USA, if Pioneer USA's board of directors determines that
          termination of the merger agreement is required in order for the board
          to comply with its fiduciary duties; or

     o    by Pioneer, if there shall have occurred any event, circumstance,
          condition, development or occurrence causing, resulting in or having,
          or reasonably expected to cause, result in or have, a material adverse
          effect (1) on any partnership's business, operations, properties,
          taken as a whole, condition, financial or otherwise, results of
          operations, assets, taken as a whole, liabilities, cash flows or
          prospects, (2) on market prices for oil and gas prevailing generally
          in the oil and gas industry since the date of determination of the oil
          and gas commodity prices used in the determination of the merger value
          for each partnership, (3) on the price of Pioneer common stock or (4)
          on the oil and gas industry generally.

     If the merger agreement is validly terminated or the merger of any
partnership is abandoned, none of Pioneer, Pioneer USA nor any such partnership
shall have any liabilities or obligations to the other parties based on the
merger agreement or such merger except:

     o    Pioneer will pay all expenses and fees of each partnership in
          connection with the merger of that partnership incurred before the
          termination of the merger agreement or abandonment of the merger of
          the partnership; and



                                      -53-
   63

     o     a party will be liable if that party is in breach of the merger
          agreement.

AMENDMENTS; WAIVERS

     Any provision of the merger agreement may be amended prior to the effective
time if the amendment is in writing and signed by Pioneer and Pioneer USA;
provided, that after the approval of the merger proposals by the limited
partners of each partnership, no amendment shall, without the further approval
of the limited partners of each partnership:

     o    adversely change the type or amount of, or the method of determining,
          the consideration to be received in exchange for any partnership
          interests in the partnership; or

     o    materially and adversely affect the rights of the limited partners of
          the partnership, other than a termination of the merger agreement or
          abandonment of the merger of the partnership.

     Prior to the effective time, the parties may:

     o    extend the time for the performance of any of the obligations of the
          parties;

     o    waive any inaccuracies in the representations and warranties in the
          merger agreement or in a document delivered pursuant to the merger
          agreement; and

     o    waive compliance with any agreement or condition in the merger
          agreement.

Any such extension or waiver will be valid only if it is in writing and signed
by the party against whom the extension or waiver is to be effective.



                                      -54-
   64

                              THE SPECIAL MEETINGS

TIME AND PLACE; PURPOSE

     The special meeting of the limited partners of each partnership will be
held on         , 2001, at 10:00 a.m., at the Dallas Marriott Las Colinas Hotel,
Irving, Texas 75039. The purpose of each special meeting, and any adjournment or
postponement of the special meeting for each partnership, is for the limited
partners of each partnership to consider and vote on the following matters:

     o A proposal to approve an Agreement and Plan of Merger dated as of       ,
2001, to be effective as of the closing date, among Pioneer, Pioneer USA and
each of the partnerships. Each partnership that approves this proposal will
merge with and into Pioneer USA, with Pioneer USA surviving the merger. Each
partnership interest of a participating partnership will be converted into
Pioneer common stock and an amount of cash. The number of shares of common stock
Pioneer will offer and the amount of cash to be paid for all partnership
interests of a participating partnership will be based on (1) the participating
partnership's merger value and (2) the average closing price of the Pioneer
common stock, as reported by the New York Stock Exchange, for the ten trading
days ending three business days before the date of the special meeting for the
partnership. The merger value for a participating partnership is equal to the
sum of the present value of estimated future net revenues from the partnership's
oil and gas reserves and its net working capital, in each case as of March 31,
2001. For purposes of illustration in this document, we have calculated the
merger value based on each partnership's working capital as of December 31,
2000, and the number of shares to be issued based on an assumed average closing
price of $18.00 per share of Pioneer common stock. We will update the
calculation of the merger value using the March 31, 2001 working capital of each
partnership before mailing this document to the limited partners, and prior to
the date of the special meeting for each partnership, we will update the number
of shares to be issued using the actual average closing price of Pioneer common
stock for the ten trading days ending three business days before the date of the
special meeting. The Pioneer common stock and the cash payment will be allocated
among the partners based on the liquidation provisions of each partnership
agreement. Pioneer USA will not receive any Pioneer common stock or cash payment
for its partnership interests in the participating partnerships. However, as a
result of each merger, Pioneer USA will own 100% of the properties of each
participating partnership, including properties attributable to its partnership
interests in those partnerships.

     o A proposal to amend the partnership agreement of each partnership to
permit the partnership's merger with Pioneer USA. If the amendment is not
approved, that partnership cannot merge into Pioneer USA even if the partners of
that partnership approve the merger agreement.

     o A proposal (A) to approve the opinion issued to Pioneer USA by
on behalf of the limited partners of each partnership that neither the grant nor
the exercise of the right to approve the merger of the partnership by its
limited partners (1) will result in the loss of any limited partner's limited
liability or (2) will adversely affect the federal income tax classification of
the partnership or any of its limited partners and (B) to approve the selection
of      as special legal counsel for the limited partners of each partnership to
render such legal opinion.

     o Other business that properly comes before the special meeting or any
adjournments or postponements of the special meeting. Pioneer USA is not aware
of any other business for the special meeting.

     The Delaware Revised Uniform Limited Partnership Act and the Texas Revised
Limited Partnership Act require limited partner approval and adoption of the
merger agreement and the merger amendment. Generally, the partnership agreement
of each partnership requires that special legal counsel for the limited partners
render its legal opinion related to the limited partners' approval of the merger
of that partnership. See "The Merger of Each Partnership -- Legal Opinion for
Limited Partners" on page 43 of this document.

     PIONEER USA'S BOARD OF DIRECTORS UNANIMOUSLY DETERMINED THAT THE MERGER OF
EACH PARTNERSHIP IS ADVISABLE, FAIR TO THE UNAFFILIATED LIMITED PARTNERS OF THE
PARTNERSHIP, AND IN THEIR BEST INTERESTS. THE BOARD RECOMMENDS THAT THE
UNAFFILIATED LIMITED PARTNERS VOTE FOR THE MERGER PROPOSALS FOR EACH PARTNERSHIP
IN WHICH THEY OWN AN INTEREST. ALTHOUGH PIONEER USA'S BOARD OF DIRECTORS HAS
ATTEMPTED TO FULFILL ITS FIDUCIARY DUTIES TO THE LIMITED PARTNERS OF EACH
PARTNERSHIP, PIONEER USA'S BOARD OF DIRECTORS HAD CONFLICTING INTERESTS IN
EVALUATING EACH MERGER BECAUSE EACH MEMBER OF ITS BOARD OF DIRECTORS IS ALSO AN
OFFICER OF PIONEER.

RECORD DATE; VOTING RIGHTS AND PROXIES

     Only limited partners of record of each partnership at the close of
business on         , 2001 are entitled to notice of and to vote at the special
meeting for the partnership in which they own partnership interests, or any
adjournments or postponements of such special meeting. Pioneer USA is entitled
to vote partnership interests it holds as a limited partner in all of the
partnerships except:



                                      -55-
   65

              Parker & Parsley 85-A, Ltd.
              Parker & Parsley 85-B, Ltd.
              Parker & Parsley Private Investment 85-A, Ltd.
              Parker & Parsley Selected 85 Private Investment, Ltd.
              Parker & Parsley Private Investment 86, Ltd.
              Parker & Parsley 91-A, L.P.
              Parker & Parsley 91-B, L.P.

Pioneer USA's affiliates are also entitled to vote partnership interests they
hold as limited partners in all but the seven partnerships listed above.
However, no affiliates of Pioneer USA own such interests. See "Ownership of
Partnership Interests" on page 61 of this document.

     Limited partners of record of each partnership are entitled to vote at the
partnership's special meeting based on the limited partners' respective
percentage of partnership interests in the partnership. Each limited partner
will receive a proxy card for all partnerships in which that limited partner
holds partnership interests. The proxy card will indicate the amount of Pioneer
common stock and cash offered with respect to such partnership interests in each
partnership. Although the number of shares of Pioneer common stock offered as
shown on the proxy card may change, the value of Pioneer common stock offered as
shown on the proxy card will not be adjusted. The percentage of partnership
interests that a limited partner holds in a partnership is determined by
comparing the amount of the limited partner's initial investment, including any
additional assessments, in the partnership to the total investment of all
partners, including any additional assessments, in the partnership. The
aggregate initial investment, including any additional assessments, in each of
the partnerships by the limited partners is set forth in Table 1 of Appendix A.

     A limited partner of record may grant a proxy to vote for or against, or
may abstain from voting on, the merger proposals applicable to each of the
partnerships in which the limited partner holds partnership interests. To be
effective for purposes of granting a proxy to vote on the merger proposals
applicable to each partnership, a proxy card must be properly completed,
executed and delivered to Pioneer USA in person or by mail, telegraph, telex or
facsimile before the special meeting for the partnership. All partnership
interests represented by properly executed proxies will, unless these proxies
have been previously revoked, be voted in accordance with the instructions
indicated in these proxies. If no instructions are indicated, the partnership
interests will be voted for approval and adoption of the merger proposals. A
properly executed proxy card for a partnership marked abstain is counted as
present for purposes of determining the presence or absence of a quorum at the
special meeting for the partnership, but will not be voted. Accordingly,
abstentions will have the same effect as a vote against the merger proposals.

     Unrevoked proxies granted in the proxy cards for a partnership will be
voted at the special meeting for that partnership or at any adjournment or
postponement of the special meeting, if received by Pioneer USA before the
special meeting for the partnership. Proxies granted in the proxy cards for a
partnership will remain valid until the completion of the special meeting for
the partnership. Each partnership agreement requires that a meeting be held
within 60 days of the date of mailing of the notice of meeting. None of the
partnership agreements specifically addresses, and Pioneer USA has not sought
any opinions of counsel as to, whether proxies may be voted at a meeting
originally scheduled to be held within 60 days of the sending of the notice and
adjourned or postponed to a date more than 60 days after the date of notice.
Pioneer USA will not accept a vote of the limited partners of any partnership in
such circumstances unless it receives an opinion of counsel that such a vote
would be valid.

     The inspector of election appointed for the special meeting for each
partnership will tabulate the votes cast by proxy or in person at the special
meeting.

     Pioneer USA does not know of any matters other than the approval of the
merger proposals for each partnership that are to come before the special
meeting for the partnership. If any other matter or matters are properly
presented for action at the special meeting for each partnership, the persons
named in the enclosed form of proxy and acting under the proxy will have the
discretion to vote on those matters in accordance with their best judgment.

REVOCATION OF PROXIES

     You may revoke a proxy you have given at any time before that proxy is
voted at the special meeting for each partnership in which you own an interest
by:

     -    giving written notice of revocation to Pioneer USA;

     -    signing and returning a later dated proxy; or

     -    voting in person at the special meeting.

Your notice of revocation will not be effective until Pioneer USA receives it at
or before the special meeting for each partnership in which you own an interest.
Your presence at any such special meeting will not automatically



                                      -56-
   66

revoke your proxy in a proxy card. Revocation during any such special meeting
will not affect votes previously taken.

     You may deliver your written notice of revocation in person or by mail,
telegraph, telex, or facsimile. Any written notice of revocation must specify
your name and limited partner number as shown on your proxy card and the name of
the partnership to which your revocation relates.

SOLICITATION OF PROXIES

     We are soliciting your proxy pursuant to this document. Pioneer will pay
all expenses, including those described below, incurred in connection with
solicitation of the enclosed proxy.

     Pioneer USA has retained           to assist in the solicitation of proxies
from the limited partners of each partnership. The total fees and expenses of
     are estimated to aggregate $225,000 and will be paid by Pioneer. In
addition to solicitation by use of the mail, proxies may be solicited by
     , by other outside contractors and by directors, officers and employees of
Pioneer and Pioneer USA in person or by telephone, telegram, facsimile or
e-mail. Pioneer will pay the fees and expenses of any outside contractors which
may be retained to solicit proxies, which fees and expenses are estimated to
aggregate $       . The directors, officers and employees will not be
additionally compensated, but may be reimbursed for out-of-pocket expenses
incurred in connection with the solicitation.

     Arrangements may also be made with other brokerage firms, banks,
custodians, nominees and fiduciaries for the forwarding of proxy solicitation
materials to owners of limited partnership interests held of record by those
persons. Pioneer will reimburse those persons for reasonable expenses incurred
in forwarding those materials.

     Pioneer USA has also retained        to act as information agent to perform
consulting, administration and clerical work with respect to the merger of each
partnership. Pioneer USA has agreed to indemnify    against certain liabilities,
including liabilities under the federal securities laws.            will also be
responsible for the receipt and tabulation of the proxy cards. The fees and
expenses of     for its services as information agent and tabulator are included
in the aggregate amount set forth above.

     We intend to mail certificates representing shares of Pioneer common stock
and checks for the cash payment to the partners of record of each participating
partnership promptly after completing the merger of that partnership.
Certificates representing partnership interests will be automatically canceled,
and you will not have to surrender your certificates to receive the Pioneer
common stock and cash payment.

QUORUM

     The presence in person or by properly executed proxy of a majority of
limited partnership interests entitled to vote in each partnership is necessary
to constitute a quorum at that partnership's special meeting.

     If a quorum is not present at any special meeting, the limited partners
entitled to vote who are present or represented by proxy at that special meeting
may adjourn or postpone that special meeting without notice until a quorum is
present. If a quorum is present at the adjourned or postponed meeting, any
business may be transacted that may have been transacted at the special meeting
had a quorum originally been present. If the adjournment or postponement is for
more than 30 days or if after the adjournment or postponement a new record date
is fixed for the adjourned or postponed meeting, a notice of the adjourned or
postponed meeting shall be given to each limited partner of record entitled to
vote at the adjourned or postponed meeting. The persons named as proxies intend
to vote in favor of any motion to adjourn or postpone the special meeting of any
partnership if, prior to the special meeting, they have not received sufficient
proxies to approve the merger of the partnership as described in this document.
This process will be repeated at any adjourned or postponed meeting until
sufficient proxies to vote in favor of the merger of the partnership have been
received or it appears that sufficient proxies will not be received.

REQUIRED VOTE; BROKER NON-VOTES

     Approval of the merger proposals for each partnership requires the
affirmative vote of the limited partners holding a majority of limited
partnership interests in that partnership, except that Parker & Parsley 91-A,
L.P. and Parker & Parsley 91-B, L.P. each require the favorable vote of the
holders, other than Pioneer USA, of 66 2/3% of its limited partnership interests
to approve those merger proposals. Pioneer USA is entitled to vote its
partnership interests on the merger proposals for each partnership except as set
forth under "The Special Meetings -- Record Date; Voting Rights and Proxies" on
page 55. Therefore, approval of at least a majority, and for Parker & Parsley
91-A, L.P. and Parker & Parsley 91-B, L.P., at least 66 2/3%, of the
unaffiliated limited partners is not required to approve the merger proposals
except for the partnerships listed under "The Special Meetings -- Record Date;
Voting Rights and Proxies" on page 55 of this document, in which Pioneer USA has
no voting rights.



                                      -57-
   67

     Brokers, if any, who hold partnership interests in street name for
customers have the authority to vote on "routine" proposals when they have not
received instructions from beneficial owners. However, these brokers are
precluded from exercising their voting discretion with respect to the approval
and adoption of non-routine matters such as the merger proposals and thus,
absent specific instructions from the beneficial owner of the partnership
interests, brokers are not empowered to vote the partnership interests with
respect to the merger proposals. These "broker non-votes" will have the effect
of a vote against the merger proposals.

PARTICIPATION BY ASSIGNEES

     Pioneer USA has the discretionary authority granted to it under each
partnership agreement to withhold its consent to the substitution of any
assignees as partners of the partnership. To facilitate the notification given
to limited partners of each partnership about the merger of the partnership,
Pioneer USA intends to exercise that authority and withhold its consent to the
substitution of any assignees as partners of the partnership from the date on
which this document is initially filed with the SEC until the earlier to occur
of the closing date of the merger of the partnership, or the termination or
abandonment of the transaction by Pioneer and Pioneer USA.

SPECIAL REQUIREMENTS FOR SOME LIMITED PARTNERS

     Pioneer USA may require that any proxy card executed by an entity, such as
a trust, corporation, or partnership, be accompanied by evidence or an opinion
of counsel that such entity:

     o    has met all requirements of its governing instruments; and

     o    is authorized to execute and deliver the proxy card under the laws of
          the jurisdiction under which the entity was organized.

     Pioneer USA will require the named trustee and the beneficial owner of
trusts, including individual retirement accounts, to execute the proxy card. In
some cases, Pioneer USA may provide a limited partner with an envelope,
pre-addressed to his individual retirement account trustee, so that the limited
partner may forward his executed proxy card to the trustee for the trustee's
signature, if necessary, and subsequent delivery to Pioneer USA. Delivery of a
proxy card to the trustee, with or without the use of a pre-addressed envelope,
and delivery of a proxy card from the trustee to Pioneer USA are at the risk of
the limited partner.

VALIDITY OF PROXY CARDS

     A proxy card will not be valid unless it has been properly completed and
executed and timely delivered to Pioneer USA's information agent with all other
required documents. Pioneer USA will determine all questions as to the validity,
form, eligibility, time of receipt and acceptance of a proxy card and its
determination will be final and binding. Pioneer USA's interpretation of the
terms and conditions of the merger of each partnership, including the
instructions for the proxy card, will also be final and binding.

     A proxy card will not be valid until any irregularities have been cured or
waived. If Pioneer USA does not waive the irregularities, it will return the
defective proxy card to the limited partner as soon as practicable. Pioneer USA
is under no duty to give notification of defects in a proxy card and will incur
no liability if it fails to give such notification.

     Delivery of a proxy card is at the risk of the limited partner. A proxy
card will be effective for purposes of voting only when it is actually received
by Pioneer USA's information agent. To ensure receipt of the proxy card and all
other required documents, Pioneer USA suggests that limited partners use
overnight courier delivery or certified or registered mail, return receipt
requested.

LOCAL LAWS

     Proxy solicitations will not be made to, nor will proxy cards be accepted
from, limited partners of any partnership in any jurisdiction in which the
solicitations would not be in compliance with federal and state securities or
other laws.



                                      -58-
   68

           COMPARATIVE PER SHARE MARKET PRICE AND DIVIDEND INFORMATION

     The table below sets forth, for the calendar quarters indicated, the
reported high and low closing prices of Pioneer common stock as reported on the
New York Stock Exchange Composite Transaction Tape, in each case based on
published financial sources. Pioneer's board of directors did not declare
dividends to the holders of Pioneer common stock during 1999, 2000 or the three
months ended March 31, 2001. None of the partnership interests of any
partnership are traded on a national stock exchange or in any other significant
market. No liquid market exists for interests in any of the partnerships. See
Table 15 of Appendix A for historical information about recent trades per $1,000
limited partner investment in each partnership for the three months ended March
31, 2001 and the years ended December 31, 2000 and 1999. The average quarterly
cash distributions per $1,000 limited partner investment in each partnership for
1999, 2000 and the year-to-date in 2001 are set forth in Table 7 of Appendix A.

     On April 16, 2001, the last full trading day prior to the announcement of
the proposed merger of each partnership, Pioneer common stock closed at $17.27
per share. On         , 2001, Pioneer common stock closed at $ per share.



                                 PIONEER COMMON STOCK
                                     MARKET PRICE
                              -------------------------
                                 HIGH           LOW
                              ----------     ----------
                                       
2001
     First quarter            $    20.24     $    15.45

2000
     Fourth quarter                20.63          12.44
     Third quarter                 16.06          10.63
     Second quarter                15.63           9.00
     First quarter                 10.75           6.75

1999
     Fourth quarter                11.50           7.63
     Third quarter                 12.81           9.38
     Second quarter                13.19           7.06
     First quarter                  9.75           5.00


     We urge the limited partners of each partnership to obtain current market
quotations prior to making any decision with respect to the merger of the
partnership.



                                      -59-
   69

                        INTERESTS OF PIONEER, PIONEER USA
                        AND THEIR DIRECTORS AND OFFICERS

     A number of conflicts of interest are inherent in the relationships among
each partnership, Pioneer, Pioneer USA and their respective directors and
officers.

CONFLICTING DUTIES OF PIONEER USA, INDIVIDUALLY AND AS GENERAL PARTNER

     Pioneer USA, as general partner of each partnership, has a duty to manage
each partnership in the best interests of the limited partners. Pioneer USA also
has a duty to operate its business for the benefit of its sole stockholder,
Pioneer. Consequently, Pioneer USA's duties to the limited partners of each
partnership may conflict with its duties to Pioneer.

     The members of the board of directors of Pioneer USA have a duty to cause
Pioneer USA to manage each partnership in the best interests of the limited
partners. All members of the board of directors of Pioneer USA are officers of
Pioneer and Pioneer USA. Thus, the members of the board of directors of Pioneer
USA have duties to operate Pioneer USA's business for the benefit of its sole
stockholder, Pioneer, and, as officers of Pioneer, to operate Pioneer's business
in its best interests. Consequently, the duties of the members of the board of
directors of Pioneer USA to the limited partners may conflict with the duties of
those members to Pioneer, Pioneer USA and their stockholders.

     Neither Pioneer nor Pioneer USA retained an independent representative to
negotiate on behalf of the limited partners of each partnership because:

     o    neither the partnership agreement for any partnership nor any
          applicable law provides for any procedure to identify and select an
          independent representative, unless each limited partner of the
          partnership agrees to the independent representative;

     o    Pioneer USA, as sole or managing general partner of each partnership,
          still has its fiduciary duty to the limited partners; and

     o    it would be (1) cost-prohibitive to find one or more persons to
          represent the limited partners in all of the partnerships because no
          one other than Pioneer USA owns an interest in all of the partnerships
          and (2) impractical to have 46 independent representatives.

PIONEER USA'S EMPLOYEES PROVIDE SERVICES TO THE PARTNERSHIPS

     None of the partnerships currently has any employees. Each partnership
relies on Pioneer USA's personnel. Pioneer USA provides all management functions
on behalf of each partnership. Therefore, each partnership currently competes
with Pioneer USA for the time and resources of Pioneer USA's employees.

FINANCIAL INTERESTS OF DIRECTORS AND OFFICERS

     The directors and officers of Pioneer and Pioneer USA have equity interests
in Pioneer through stock ownership, stock options and other stock-based
compensation, but do not have financial or equity interests in any partnership.
See "Ownership of Partnership Interests" on page 61. The boards of directors of
Pioneer and Pioneer USA believe that any economic benefit their directors and
officers may obtain from the merger of each partnership will be minimal, if any,
and will not result in a material economic benefit, if any, to their directors
and officers individually.

THE PARTNERSHIPS PAY OPERATOR FEES TO PIONEER USA

     Pioneer USA operates most of each partnership's wells. Each partnership has
entered into one or more standard industry operating agreements with Pioneer
USA. Those operating agreements establish the base fee paid by the partnership
to Pioneer USA for its lease operating services. That base fee adjusts annually
based on a rate established by the Council of Petroleum Accountants Society, or
COPAS, for the oil and gas industry.




                                      -60-
   70

                       OWNERSHIP OF PARTNERSHIP INTERESTS

     Pioneer does not directly own any partnership interests in any partnership.
Pioneer beneficially owns all of Pioneer USA's partnership interests in each
partnership. Table 6 of Appendix A to this document contains the voting
percentage as of March 31, 2001, of the outstanding limited partnership
interests for each partnership that are beneficially owned by Pioneer USA as a
limited partner. As of March 31, 2001, no person or entity known by Pioneer USA
beneficially owns more than 5% of the outstanding limited partnership interests
in any partnership, except in Parker & Parsley 81-I, Ltd., Parker & Parsley
82-I, Ltd. and Parker and Parsley 82-III, Ltd. In those partnerships, Pioneer
USA repurchased and now owns partnership interests representing the following
beneficial ownership percentages:


                                                    
              Parker & Parsley 81-I, Ltd.                  5.84%
              Parker & Parsley 82-1, Ltd.                 10.73%
              Parker & Parsley 82-III, Ltd.                5.97%


Pioneer USA has sole investment and voting power with respect to partnership
interests it beneficially owns.

     Except as set forth above, none of Pioneer, Pioneer USA, or, to the
knowledge of Pioneer USA, any of their directors or executive officers, or any
associate or majority-owned subsidiary of Pioneer, Pioneer USA or any such
director or officer:

     o    beneficially owns any partnership interests of any partnership; or

     o    has effected any transactions in any partnership interests of any
          partnership during the past 60 days.

            TRANSACTIONS AMONG THE PARTNERSHIPS, PIONEER, PIONEER USA
                        AND THEIR DIRECTORS AND OFFICERS

     Except as described in this document, there have not been any transactions,
negotiations or material contacts between Pioneer, Pioneer USA, any of their
respective subsidiaries, or, to the knowledge of Pioneer and Pioneer USA, any
director or executive officer of Pioneer or Pioneer USA or any associate of any
such persons, on the one hand, and any partnership or any of its general
partners, including Pioneer USA, directors, officers or affiliates, on the other
hand, that are required to be disclosed pursuant to the rules and regulations of
the SEC. Except as described in this document, none of Pioneer, Pioneer USA, or,
to the knowledge of Pioneer and Pioneer USA, any director or executive officer
of Pioneer or Pioneer USA, has any agreement, arrangement or understanding with
any other person with respect to any securities of any partnership.

     During March 2001, Pioneer offered to acquire all of the direct oil and gas
interests owned by some former officers and employees of Pioneer and Pioneer USA
in properties in which Pioneer and Pioneer USA own interests. The terms of those
purchases and the method of establishing the purchase price payable to such
individuals are the same as those used to determine the reserve value portion of
the merger value for each partnership described in this document, except that
the NYMEX futures prices were as of a different date in March 2001, and the
consideration to be paid in the purchases of the direct oil and gas interests is
all cash since offering and registering Pioneer common stock in those purchases
is cost-prohibitive due to the small size of such transactions. Similarly,
during 2000, Pioneer purchased all of the direct oil and gas interests held by
Scott D. Sheffield, its chairman of the board of directors and chief executive
officer, for $0.2 million.

     Additionally, in December 2000, Pioneer received the approval of the
partners of 13 employee limited partnerships to merge with Pioneer USA for
aggregate merger consideration of $2.0 million. Of the total merger
consideration, $0.3 million was paid to current Pioneer employees. The terms of
those mergers and the method of establishing the merger values for those
partnerships were the same as those used to determine the merger value for each
partnership described in this document, except that the NYMEX futures prices
were as of August 25, 2000, and the consideration paid in those mergers was all
cash. As with the purchases of the direct oil and gas interests described above,
offering and registering Pioneer common stock in those mergers was
cost-prohibitive due to the small size of such transaction.

     If you approve the merger of each partnership in which you own an interest,
there are various ways that Pioneer USA may use the properties. Pioneer USA may
continue to operate the properties, it may sell the properties to third parties,
including a royalty trust, or it may spin-off the properties to its stockholder.
Although Pioneer USA plans to operate the properties in the immediate future
following completion of the merger of each partnership, it has not decided how
to use the properties in the long-term.



                                      -61-
   71

                                   MANAGEMENT

PIONEER

     The following information sets forth the age, business experience during
the past five years, positions and offices with Pioneer, and periods of service
of each director and executive officer of Pioneer.



                NAME                        AGE                                  POSITION
                ----                        ---                                  --------
                                                  
Scott D. Sheffield                           48         Chairman of the Board of Directors, President and Chief
                                                        Executive Officer
Timothy L. Dove                              44         Executive Vice President and Chief Financial Officer
Dennis E. Fagerstone                         52         Executive Vice President
Mark L. Withrow                              53         Executive Vice President, General Counsel and Secretary
Danny L. Kellum                              46         Executive Vice President -- Domestic Operations
James R. Baroffio                            69         Director
R. Hartwell Gardner                          66         Director
James L. Houghton                            70         Director
Jerry P. Jones                               69         Director
Charles E. Ramsey, Jr.                       64         Director
Robert L. Stillwell                          64         Director


     Scott D. Sheffield. Mr. Sheffield, a distinguished graduate of the
University of Texas with a Bachelor of Science degree in Petroleum Engineering,
has been the Chairman of the Board of Directors of Pioneer since August 1999 and
the President and Chief Executive Officer of Pioneer since August 1997. He was
the President and a director of Parker & Parsley Petroleum Company since May
1990 and was the Chairman of the Board of Directors and Chief Executive Officer
of Parker & Parsley Petroleum Company since October 1990. Mr. Sheffield was the
sole director of Parker & Parsley Petroleum Company from May 1990 until October
1990. Mr. Sheffield joined Parker & Parsley Development Company, a predecessor
of Parker & Parsley Petroleum Company, as a petroleum engineer in 1979. Mr.
Sheffield served as Vice President -- Engineering of Parker & Parsley
Development Company from September 1981 until April 1985, when he was elected
President and a director. In March 1989, Mr. Sheffield was elected Chairman of
the Board of Directors and Chief Executive Officer of Parker & Parsley
Development Company. Before joining Parker & Parsley Development Company 's
predecessor, Mr. Sheffield was employed as a production and reservoir engineer
for Amoco Production Company.

     Timothy L. Dove. Mr. Dove, a graduate of Massachusetts Institute of
Technology with a Bachelor of Science degree in Mechanical Engineering and the
University of Chicago with an M.B.A., has been Executive Vice President and
Chief Financial Officer of Pioneer since February 2000. He was Executive Vice
President -- Business Development of Pioneer from August 1997 until February
2000. Mr. Dove joined Parker & Parsley Petroleum Company in May 1994 as Vice
President -- International and was promoted to Senior Vice President -- Business
Development in October 1996, in which position he served until August 1997.
Before joining Parker & Parsley Petroleum Company, Mr. Dove was employed with
Diamond Shamrock Corp., and its successor, Maxus Energy Corp., in various
capacities in international exploration and production, marketing, refining, and
planning and development.

     Dennis E. Fagerstone. Mr. Fagerstone, a graduate of the Colorado School of
Mines with a B.S. in Petroleum Engineering, has been an Executive Vice President
of Pioneer since August 1997. Mr. Fagerstone served as Executive Vice President
and Chief Operating Officer of MESA Inc. from March 1997 until August 1997. Mr.
Fagerstone served as Senior Vice President and Chief Operating Officer of MESA
Inc. from October 1996 to February 1997, and served as Vice President --
Exploration and Production of MESA Inc. from May 1991 to October 1996. Mr.
Fagerstone served as Vice President -- Operations of MESA Inc. from June 1988
until May 1991.

     Mark L. Withrow. Mr. Withrow, a graduate of Abilene Christian University
with a Bachelor of Science degree in Accounting and Texas Tech University with a
J.D. degree, has been the Executive Vice President, General Counsel and
Secretary of Pioneer since August 1997. He served as Vice President -- General
Counsel of Parker & Parsley Petroleum Company from February 1991 until January
1995, and served as Senior Vice President and General Counsel of Parker &
Parsley Petroleum Company from January 1995 until August 1997. He was Parker &
Parsley Petroleum Company's Secretary from August 1992 until August 1997. Mr.
Withrow joined Parker & Parsley Development Company in January 1991. Before
joining Parker & Parsley Development Company, Mr. Withrow was the managing
partner of the law firm of Turpin, Smith, Dyer, Saxe & MacDonald, Midland,
Texas.

     Danny L. Kellum. Mr. Kellum, a graduate of Texas Tech University with a
Bachelor of Science degree in Petroleum Engineering in 1979, has been Executive
Vice President -- Domestic Operations of Pioneer since May 2000. From January
2000 until May 2000, Mr. Kellum served as Vice President - Domestic Operations.
From August 1997 until December 1999, Mr. Kellum served as Vice President --
Permian Division. Mr. Kellum served as Spraberry District Manager for Parker &
Parsley Petroleum Company from 1989 until 1994 and as Vice President of



                                      -62-
   72

the Spraberry and Permian Divisions for Parker & Parsley Petroleum Company until
August of 1997. He joined Parker & Parsley Petroleum Company in 1981 as
Operations Engineer after a brief career with Mobil Oil Corporation.

     James R. Baroffio. Dr. Baroffio received a B.A. in Geology at the College
of Wooster, Ohio, an M.S. in Geology at Ohio State University, and a Ph.D. in
Geology at the University of Illinois. Before becoming a director of Pioneer in
December 1997, Dr. Baroffio enjoyed a long career with Standard Oil Company of
California, the predecessor of Chevron Corporation, where he served as
President, Chevron Research and Technology Center from 1980 to 1985 and
eventually retired as President of Chevron Canada Resources in 1994. Dr.
Baroffio was a member of the Board of Directors of the Rocky Mountain Oil & Gas
Association and Chairman of the U.S. National Committee of the World Petroleum
Congress. His community leadership positions included membership on the Board of
Directors of Glenbow Museum and the Nature Conservancy of Canada, as well as
serving as President of the Alberta Nature Conservancy.

     R. Hartwell Gardner. Mr. Gardner, a graduate of Colgate University with a
Bachelor of Arts degree in Economics and Harvard University with an M.B.A.,
became a director of Pioneer in August 1997. He served as a director of Parker &
Parsley Petroleum Company from November 1995 until August 1997. Until October
1995, Mr. Gardner was the Treasurer of Mobil Oil Corporation and Mobil
Corporation from 1974 and 1976, respectively. Mr. Gardner is a member of the
Financial Executives Institute of which he served as Chairman in 1986/1987 and
is a Director of Oil Investment Corporation Ltd. and Oil Casualty Investment
Corporation Ltd., Pembroke, Bermuda.

     James L. Houghton. Mr. Houghton is a certified public accountant and a
graduate of Kansas University with a Bachelor of Science degree in Accounting,
as well as a Bachelor of Laws degree. Mr. Houghton has served as a director of
Pioneer since August 1997, and as a director of Parker & Parsley Petroleum
Company from October 1991 until August 1997. Until October 1991, Mr. Houghton
was the lead oil and gas tax specialist for the accounting firm of Ernst & Young
LLP, was a member of Ernst & Young's National Energy Group, and had served as
its Southwest Regional Director of Tax. Mr. Houghton is a member of the American
Institute of Certified Public Accountants, a member of the Oklahoma Society of
Certified Public Accountants, a former Chairman of its Federal and Oklahoma
Taxation Committee and past President of the Oklahoma Institute of Taxation. He
has also served as a Director for the Independent Petroleum Association of
America and as a member of its Tax Committee.

     Jerry P. Jones. Mr. Jones earned a Bachelor of Science degree from West
Texas State College in 1953 and a Bachelor of Law degree from the University of
Texas School of Law in 1959. Mr. Jones has served as a director of Pioneer since
August 1997, and as a director of Parker & Parsley Petroleum Company from May
1991 until August 1997. Mr. Jones has been an attorney with the law firm of
Thompson & Knight, P.C., Dallas, Texas, since September 1959 and was a
shareholder in that firm until January 1998, when he retired and became of
counsel to the firm. Mr. Jones specialized in civil litigation, especially in
the area of energy disputes.

     Charles E. Ramsey, Jr. Mr. Ramsey is a graduate of the Colorado School of
Mines with a Petroleum Engineering degree and a graduate of the Smaller Company
Management program at the Harvard Graduate School of Business Administration.
Mr. Ramsey has served as a director of Pioneer since August 1997. Mr. Ramsey
served as a director of Parker & Parsley Petroleum Company from October 1991
until August 1997. Since October 1991, he has operated an independent management
and financial consulting firm. From June 1958 until June 1986, Mr. Ramsey held
various engineering and management positions in the oil and gas industry and,
for six years before October 1991, was a Senior Vice President in the Corporate
Finance Department of Dean Witter Reynolds Inc. in Dallas, Texas. His industry
experience includes 12 years of senior management experience in the positions of
President, Chief Executive Officer and Executive Officer and Executive Vice
President of May Petroleum Inc. Mr. Ramsey is also a former director of MBank
Dallas, the Dallas Petroleum Club and Lear Petroleum Corporation.

     Robert L. Stillwell. Mr. Stillwell, a graduate of the University of Texas
with a B.B.A. and the University of Texas School of Law with a J.D., has served
as a director of Pioneer since August 1997. He served as a director of MESA Inc.
from January 1992 until August 1997, as a member of the Advisory Committee of
Mesa, L.P., a predecessor of MESA Inc., from December 1985 until December 1991,
and as a director of MESA Inc. in its original corporate form from 1968 until
January 1987. Mr. Stillwell has been a partner in the law firm of Baker & Botts,
L.L.P., Houston, Texas, for more than five years.

PIONEER USA

     The following information sets forth the age, business experience during
the past five years, positions and offices with Pioneer USA, and periods of
service of each director and executive officer of Pioneer USA.


                                      -63-
   73


                NAME                        AGE                            POSITION
                ----                        ---                            --------
                                                  
Scott D. Sheffield                           48         President
Timothy L. Dove                              44         Director, Executive Vice President and
                                                        Chief Financial Officer
Dennis E. Fagerstone                         52         Director and Executive Vice President
Mark L. Withrow                              53         Director, Executive Vice President,
                                                        General Counsel and Secretary
Danny L. Kellum                              46         Director and Executive Vice President


     Scott D. Sheffield. Mr. Sheffield has been the President of Pioneer USA
since August 1997 and served as the Chairman of the Board of Directors of
Pioneer USA from August 1997 until June 1999. He served as a Director of Pioneer
USA's predecessor, Parker & Parsley Petroleum USA, Inc., from January 1991 until
August 1997. He was an Executive Vice President of Parker & Parsley Petroleum
USA, Inc. from December 1995 until August 1997. He was the President of Parker &
Parsley Petroleum USA, Inc. from December 1993 until December 1995. Mr.
Sheffield was President and Chief Executive Officer of Parker & Parsley
Petroleum USA, Inc. from January 1991 until December 1993. Mr. Sheffield's other
business experience and biographical information are set forth above under
"Management -- Pioneer."

     Timothy L. Dove. Mr. Dove has been a Director of Pioneer USA since August
1997 and has been Executive Vice President and Chief Financial Officer of
Pioneer USA since February 2000. He was the Executive Vice President -- Business
Development of Pioneer USA from August 1997 until February 2000. He served as a
Director of Parker & Parsley Petroleum USA, Inc. from June 1997 until August
1997. He was a Senior Vice President of Parker & Parsley Petroleum USA, Inc.
from October 1996 until August 1997. He was a Vice President of Parker & Parsley
Petroleum USA, Inc. from December 1995 until October 1996. Mr. Dove's other
business experience and biographical information are set forth above under
"Management -- Pioneer."

     Dennis E. Fagerstone. Mr. Fagerstone has been a Director of Pioneer USA
since August 1997 and an Executive Vice President of Pioneer USA since August
1997. Mr. Fagerstone's other business experience and biographical information
are set forth above under "Management -- Pioneer."

     Mark L. Withrow. Mr. Withrow has been a Director of Pioneer USA since
August 1997. He became an Executive Vice President, the General Counsel and the
Secretary of Pioneer USA in August 1997. He served as a Director of Parker &
Parsley Petroleum USA, Inc. from January 1996 until August 1997. He was a Senior
Vice President and the Secretary of Parker & Parsley Petroleum USA, Inc. from
January 1995 until August 1997. He was a Vice President and the Secretary of
Parker & Parsley Petroleum USA, Inc. from December 1993 until January 1995. He
was a Vice President of Parker & Parsley Petroleum USA, Inc. from January 1991
until December 1993. Mr. Withrow's other business experience and biographical
information are set forth above under "Management -- Pioneer."

     Danny L. Kellum. Mr. Kellum has been a Director of Pioneer USA since
February 2000, and has been Executive Vice President of Pioneer USA since May
2000. He served as Vice President -- Domestic Operations of Pioneer USA from
January 2000 until May 2000, as Vice President -- Permian Division of Pioneer
USA from April 1998 until December 1999 and as Vice President -- Spraberry
Division of Pioneer USA from December 1997 until March 1998. Mr. Kellum's other
business experience and biographical information are set forth above under
"Management -- Pioneer."



                                      -64-
   74

                                     PIONEER

     Pioneer is a large independent exploration and production company with
total proved reserves equivalent to 3.8 trillion cubic feet of natural gas, or
628 million barrels of oil. Pioneer's proved reserves are balanced equally
between natural gas and oil, and Pioneer has a reserves-to-production ratio of
14 years. Three core areas in the United States comprise 67% of Pioneer's
reserve base: the Hugoton gas field, the West Panhandle gas field, and the
Spraberry oil and natural gas field. Pioneer also has domestic properties in
East Texas, the Gulf Coast, and the offshore Gulf of Mexico as well as a
significant international presence through its properties in Argentina, Canada,
South Africa, and Gabon.

     Pioneer seeks to increase net asset value and production by combining lower
risk development drilling with higher risk exploration activity. Pioneer has
identified over 1,700 development drilling locations on its properties in the
U.S., Argentina and Canada. Pioneer's exploration program is focused in the
deepwater Gulf of Mexico, the Gulf Coast shelf, South Africa and Gabon. Pioneer
expects significant new production from the deepwater Gulf of Mexico and South
Africa in 2002 and 2003 as it builds on its recent exploration successes in
those areas. The production from Pioneer's long-lived reserves in the Spraberry,
Hugoton and West Panhandle fields are expected to provide stable cash flows to
fund Pioneer's development and exploration activities.

     During 2000, Pioneer spent $340 million for capital expenditures to add 437
billion cubic feet of natural gas equivalent reserves. As a consequence, in 2000
Pioneer replaced 167% of its production at an all-in finding and development
cost of $.78 per Mcf equivalent. Pioneer drilled 296 wells with 90% success
worldwide, including 83 exploration and extension wells with 73% success.

     For 2001, Pioneer has budgeted $430 million of capital expenditures, a 26%
increase over 2000 capital expenditures but less than expected available cash
flow. Approximately 73% of the 2001 capital expenditure budget is for
development activities with the remaining 27% for exploration. Pioneer plans to
drill approximately 460 development wells and 26 exploratory wells in its 2001
program, and approximately 65% of the capital expenditures will be for drilling
activities in the U.S.

KEY PROJECTS TO INCREASE PRODUCTION

     Pioneer expects to increase its production of oil and gas from current
levels by 25% to 30% on a gas equivalent basis by early to mid 2003, primarily
from four projects. The projects in general build on Pioneer's recent
exploration successes.

     o    The Canyon Express project is a joint development of three deepwater
          Gulf of Mexico discoveries, including Pioneer's Aconcagua and Camden
          Hills fields. The project is being developed with a capacity to
          deliver 500 million cubic feet of natural gas per day by the summer of
          2002. Pioneer owns an 18% interest in the Canyon Express project and
          expects that production from the project will increase Pioneer's North
          American natural gas production by 30% from current levels.

     o    Pioneer's first well in offshore South Africa confirmed the presence
          of commercial oil reserves and resulted in Pioneer's plans to develop
          the Sable oil field. First production from the field is expected in
          late 2002 or early 2003 at daily rates of 25 to 30 thousand barrels
          per day. Pioneer has a 35% working interest in the field, and
          production from the project is expected to increase Pioneer's total
          oil production by more than 20%. Pioneer has also discovered oil and
          natural gas at its Boomslang prospect in offshore South Africa and
          plans a second well on the prospect later in 2001.

     o    The Devils Tower discovery was Pioneer's second in the deepwater Gulf
          of Mexico. The oil field has been successfully appraised, and
          development plans call for first production in early 2003 with
          additional drilling planned this year. Pioneer has a 25% working
          interest in the field, and production from the field is expected to
          increase Pioneer's total oil production by approximately 20% from
          current levels.

     o    In the East Texas Bossier natural gas play, Pioneer holds interests in
          over 130,000 acres and plans to drill or participate in over 35 wells
          during 2001. The play's strong initial natural gas flow rates are
          expected to provide significant new production growth.

MORE INFORMATION

     Pioneer's business, and its expectations about its future, are subject to
many risks. A more complete description of Pioneer, its business, and risks is
found in the reports that Pioneer files with the SEC. Please see "Where You Can
Find More Information" on page 74 of this document. Please also read "Risks
Associated with an Investment in Pioneer" under the caption "Risk Factors"
beginning on page 17 of this document.



                                      -65-
   75

                                THE PARTNERSHIPS

GENERAL

     Pioneer USA's predecessor, Parker & Parsley Petroleum USA, Inc. or its
predecessors or affiliates, sponsored each partnership. As a result of the
merger of Parker & Parsley Petroleum Company and MESA Inc. to form Pioneer on
August 7, 1997, Pioneer USA became the managing or sole general partner of each
partnership.

     Appendix A to this document sets forth information about each partnership,
including proved reserves, oil and gas production, average sales prices and
production costs, productive wells and developed acreage, and historical cash
distributions. In addition, the supplement for each partnership constitutes an
integral part of this document. You should read Appendix A and the supplement
carefully in their entirety.

THE DRILLING PARTNERSHIPS

     The drilling partnerships consist of the following 43 limited partnerships
that were formed from 1981 through 1991:



                             NAME                                      STATE OF FORMATION
                             ----                                      ------------------
                                                                    
Parker & Parsley 81-I, Ltd.                                                   Texas
Parker & Parsley 81-II, Ltd.                                                  Texas
Parker & Parsley 82-I, Ltd.                                                   Texas
Parker & Parsley 82-II, Ltd.                                                  Texas
Parker & Parsley 82-III, Ltd.                                                 Texas
Parker & Parsley 83-A, Ltd.                                                   Texas
Parker & Parsley 83-B, Ltd.                                                   Texas
Parker & Parsley 84-A, Ltd.                                                   Texas
Parker & Parsley 85-A, Ltd.                                                   Texas
Parker & Parsley 85-B, Ltd.                                                   Texas
Parker & Parsley Private Investment 85-A, Ltd.                                Texas
Parker & Parsley Selected 85 Private Investment, Ltd.                         Texas
Parker & Parsley 86-A, Ltd.                                                   Texas
Parker & Parsley 86-B, Ltd.                                                   Texas
Parker & Parsley 86-C, Ltd.                                                   Texas
Parker & Parsley Private Investment 86, Ltd.                                  Texas
Parker & Parsley 87-A Conv., Ltd.                                             Texas
Parker & Parsley 87-A, Ltd.                                                   Texas
Parker & Parsley 87-B Conv., Ltd.                                             Texas
Parker & Parsley 87-B, Ltd.                                                   Texas
Parker & Parsley Private Investment 87, Ltd.                                  Texas
Parker & Parsley 88-A Conv., L.P.                                           Delaware
Parker & Parsley 88-A, L.P.                                                 Delaware
Parker & Parsley 88-B Conv., L.P.                                           Delaware
Parker & Parsley 88-B L.P.                                                  Delaware
Parker & Parsley 88-C Conv., L.P.                                           Delaware
Parker & Parsley 88-C, L.P.                                                 Delaware
Parker & Parsley Private Investment 88, L.P.                                Delaware
Parker & Parsley 89-A Conv., L.P.                                           Delaware
Parker & Parsley 89-A, L.P.                                                 Delaware
Parker & Parsley 89-B Conv., L.P.                                           Delaware
Parker & Parsley 89-B, L.P.                                                 Delaware
Parker & Parsley Private Investment 89, L.P.                                Delaware
Parker & Parsley 90-A Conv., L.P.                                           Delaware
Parker & Parsley 90-A, L.P.                                                 Delaware
Parker & Parsley 90-B Conv., L.P.                                           Delaware
Parker & Parsley 90-B, L.P.                                                 Delaware
Parker & Parsley 90-C Conv., L.P.                                           Delaware
Parker & Parsley 90-C, L.P.                                                 Delaware
Parker & Parsley Private Investment 90, L.P.                                Delaware



                                      -66-
   76



                             NAME                                      STATE OF FORMATION
                             ----                                      ------------------
                                                                    
Parker & Parsley 90 Spraberry Private Development, L.P.                     Delaware
Parker & Parsley 91-A, L.P.                                                 Delaware
Parker & Parsley 91-B, L.P.                                                 Delaware


     Each drilling partnership was formed to establish long-lived oil and gas
reserves primarily by drilling low-risk development wells in the Spraberry field
of the Permian Basin of West Texas. The oil and gas properties of each drilling
partnership consist primarily of leasehold interests in producing properties
located in Texas. The partners of a drilling partnership received a tax benefit
from drilling activities in the partnership's first year. Subsequently, each
drilling partnership has regularly distributed its net cash flow. As of the date
of this document, each drilling partnership has expended all of its initial
capital contributions.

     For a discussion of transactions between each drilling partnership and
Pioneer USA, see the notes to the financial statements of each drilling
partnership included in the supplement for the partnership.

THE INCOME PARTNERSHIPS

     The income partnerships consist of the following three limited partnerships
that were formed in 1987 and 1988:



                  NAME                                           STATE OF FORMATION
                  ----                                           ------------------
                                                              
Parker & Parsley Producing Properties 87-A, Ltd.                        Texas
Parker & Parsley Producing Properties 87-B, Ltd.                        Texas
Parker & Parsley Producing Properties 88-A, L.P.                      Delaware


     The primary objective of each income partnership was to acquire long-lived,
producing oil and gas properties in the Spraberry Field of the Permian Basin of
West Texas. Subsequently, each income partnership has regularly distributed its
net cash flow. As of the date of this document, each income partnership has
expended all of its initial capital contributions.

     For a discussion of transactions between each income partnership and
Pioneer USA, see the notes to the financial statements of each income
partnership included in the supplement for the partnership.



                                      -67-
   77

                COMPARISON OF RIGHTS OF STOCKHOLDERS AND PARTNERS

GENERAL

     The rights of Pioneer stockholders are currently governed by the Delaware
General Corporation Law and the certificate of incorporation and bylaws of
Pioneer. The rights of the limited partners of each partnership are currently
governed by the Delaware Revised Uniform Limited Partnership Act or the Texas
Revised Limited Partnership Act and, in either case, the partnership agreement
of the partnership. Accordingly, on completion of the merger of each
partnership, the rights of Pioneer stockholders and of limited partners who
become Pioneer stockholders in the merger of their partnerships will be governed
by the Delaware General Corporation Law, Pioneer's certificate of incorporation
and Pioneer's bylaws. The following is a summary of the material differences
between the current rights of Pioneer stockholders and those of the limited
partners of each partnership.

     The following summary of the material differences between the Pioneer
certificate of incorporation, the Pioneer bylaws and the partnership agreement
for each partnership may not contain all the information that is important to
you. To review all provisions and differences of such documents in full detail,
please read the full text of these documents, the Delaware General Corporation
Law, the Delaware Revised Uniform Limited Partnership Act and the Texas Revised
Limited Partnership Act. Copies of the Pioneer certificate of incorporation, the
Pioneer bylaws and the partnership agreement for each partnership in which you
own an interest will be sent to you upon request. For information on how these
documents may be obtained, see "Where You Can Find More Information" on page 74.

     Pioneer's certificate of incorporation and bylaws will not be amended in
conjunction with the merger of any partnership.

SUMMARY COMPARISON OF TERMS OF SHARES OF PIONEER COMMON STOCK AND PARTNERSHIP
INTERESTS



                          SHARES                                              PARTNERSHIP INTERESTS
                          ------                                              ---------------------

                                             LIQUIDITY AND MARKETABILITY
---------------------------------------------------------------------------------------------------------------------
                                                          
Shares of Pioneer common stock are generally freely          The partnership interests of each partnership may not
transferable.  The shares of Pioneer common stock that are   be transferred if, in the opinion of counsel to the
currently outstanding are traded on the New York Stock       partnership, (1) such transfers would result in the
Exchange and the Toronto Stock Exchange, and the shares of   termination of the partnership for federal income tax
Pioneer common stock to be issued in the merger of each      purposes under Section 708 of the Internal Revenue
participating partnership have been approved for listing     Code, or (2) such transfers may not be effected without
on the New York Stock Exchange and the Toronto Stock         registration under the Securities Act of 1933 or would
Exchange upon official notice of issuance.                   result in the violation of any applicable state
                                                             securities laws.  Clause (1) is not applicable to
                                                             Parker & Parsley 85-A, Ltd., Parker & Parsley 85-B,
                                                             Ltd., Parker & Parsley Private Investment 85-A, Ltd.,
                                                             Parker & Parsley Selected 85 Private Investment, Ltd.,
                                                             Parker & Parsley Private Investment 86, Ltd., Parker &
                                                             Parsley 87-A Conv., Ltd., Parker & Parsley 87-A, Ltd.,
                                                             Parker & Parsley 87-B Conv., Ltd. and Parker & Parsley
                                                             87-B, Ltd. and Parker & Parsley Private Investment 87,
                                                             Ltd. In addition, no transferee of a partnership
                                                             interest has the right to become a substitute limited
                                                             partner unless, among other things, such substitution
                                                             is approved by Pioneer USA, who may grant or withhold
                                                             such consent in its absolute discretion.  In view of
                                                             the foregoing restrictions, it was never intended that
                                                             the partnership interests would be actively traded. No
                                                             broad-based secondary market for the partnership
                                                             interests of any partnership exists.
---------------------------------------------------------------------------------------------------------------------





                                      -68-
   78



                          SHARES                                              PARTNERSHIP INTERESTS
---------------------------------------------------------------------------------------------------------------------

                                                RIGHTS OF REPURCHASE
---------------------------------------------------------------------------------------------------------------------
                                                          
Pioneer's stockholders have no right to present their        Within the time periods specified in the partnership
shares of Pioneer common stock for repurchase by Pioneer     agreements of Parker & Parsley 82-I, Ltd., Parker &
or any other person.                                         Parsley 82-II, Ltd., Parker & Parsley 82-III, Ltd.,
                                                             Parker & Parsley 83-A, Ltd., Parker & Parsley 83-B,
                                                             Ltd. and Parker & Parsley 84-A, Ltd., a limited
                                                             partner of any of those partnerships may tender all
                                                             or, subject to some limitations, part of his
                                                             partnership interests in the partnership to Pioneer
                                                             USA for repurchase in accordance with the partnership
                                                             agreement for the partnership. See "Risk Factors --
                                                             Risk Factors Relating to the Merger of Each
                                                             Partnership -- Repurchase Rights Terminate on
                                                             Completion of the Mergers." A comparison of the merger
                                                             value for each of these partnerships and the
                                                             repurchase prices in 2001 is set forth in Table 8 of
                                                             Appendix A.
---------------------------------------------------------------------------------------------------------------------

                                MANAGEMENT, MANAGEMENT LIABILITY AND INDEMNIFICATION

----------------------------------------------------------------------------------------------------------------------
Pioneer is managed by a board of directors elected by its   Each of the partnerships is managed by Pioneer USA, which
stockholders. Under Delaware law, the directors are         generally has exclusive authority over each of the
accountable to Pioneer and its stockholders as fiduciaries  partnership's operations. The limited partners may not
and are required to perform their duties (1) in good        participate in management of the partnerships. Under
faith, (2) in a manner believed to be in the best           Delaware and Texas law, Pioneer USA and any nonmanaging
interests of Pioneer and its stockholders and (3) with      general partners of any of the partnerships are
such care, including reasonable inquiry, as an ordinarily   accountable to the partnership as fiduciaries and
prudent person in a like position would use under similar   consequently are required to exercise good faith and
circumstances. The liability of the directors is limited    integrity in all of their dealings with respect to the
pursuant to the provisions of Delaware law and Pioneer's    affairs of the partnership. Under Texas or Delaware law,
certificate of incorporation, which limits a director's     as applicable, Pioneer USA and any nonmanaging general
liability for monetary damages to Pioneer or its            partners of any of the partnerships have liability for the
stockholders for breach of the director's duty of care,     payment of partnership obligations and debts, unless
where a director fails to exercise sufficient care in       limitations upon such liability are expressly stated in
carrying out the responsibilities of office. Such           the obligation. The partnership agreement of each
provisions, however, would not protect a director for (1)   partnership provides generally that Pioneer USA, any
a breach of duty of loyalty, (2) intentional misconduct or  nonmanaging general partners of the partnership and, in
knowing violations of law, (3) unlawful dividend payments   some cases, their affiliates will be indemnified for
or redemption of stock, or (4) any transaction in which     losses relating to acts performed or omitted to be
the director derived an improper personal benefit. Such     performed in good faith and in the best interests of the
provisions do not foreclose any other remedy which might    partnership; provided that the conduct of Pioneer USA, any
be available to Pioneer or its stockholders. Pioneer's      such nonmanaging general partner or affiliate, as
certificate of incorporation and Delaware law provide       applicable, did not constitute negligence or misconduct.
broad indemnification rights to directors and officers who  Pioneer USA and any nonmanaging general partners of the
                                                            partnership may be removed by an affirmative vote of
     o    act in good faith,                                limited partners holding a majority of the outstanding
                                                            limited partnership interests in the partnership;
     o    in a manner reasonably believed to be in or not   provided, that an opinion of counsel to the limited
          opposed to the best interests of Pioneer and,     partners and acceptable to the partnership is delivered to
                                                            the partnership to the effect that the exercise of such
     o    with respect to criminal actions or proceedings,  rights by the limited partners (1) will not result in the
          without reasonable cause to believe their         loss of the limited partners' limited liability and (2)
          conduct was unlawful.                             will not adversely affect the tax status of the
                                                            partnership, Pioneer USA or the other partners.
----------------------------------------------------------------------------------------------------------------------




                                      -69-
   79



                          SHARES                                              PARTNERSHIP INTERESTS

---------------------------------------------------------------------------------------------------------------------
                                                          
Pioneer's certificate of incorporation also requires
Pioneer to indemnify its officers and directors under
some circumstances for expenses or liabilities incurred
as a result of litigation. In addition, Pioneer's
certificate of incorporation authorizes Pioneer to
advance expenses incurred in the defense of its
directors and officers. Pioneer intends to take full
advantage of those provisions and has entered into
agreements with Pioneer's directors and officers
indemnifying them to the fullest extent permitted by
Delaware law.
----------------------------------------------------------------------------------------------------------------------

                                                 MANAGEMENT CONTROL

----------------------------------------------------------------------------------------------------------------------
Pioneer's board of directors has exclusive control over      Under the partnership agreement of each partnership,
Pioneer's business and affairs subject only to the           Pioneer USA is generally vested with all management
restrictions in Pioneer's certificate of incorporation and   authority to manage, control, administer and operate
bylaws.  Pioneer's stockholders have the right to elect      the business, properties and affairs of the
members of the board of directors by a plurality vote at     partnership, including authority and responsibility for
each annual meeting of the stockholders.  The directors      overseeing all executive, supervisory and
are accountable to Pioneer and its subsidiaries as           administrative services rendered to the partnership.
fiduciaries.                                                 Pioneer USA and any nonmanaging general partners have
                                                             the right to continue to serve in such capacity unless
                                                             Pioneer USA or such nonmanaging general partner is
                                                             removed upon the affirmative vote of limited partners
                                                             holding a majority of the outstanding limited
                                                             partnership interests in the partnership; provided,
                                                             that an opinion of counsel to the limited partners,
                                                             and acceptable to the partnership, is delivered to the
                                                             partnership to the effect that the exercise of such
                                                             rights by the limited partners (1) will not result in
                                                             the loss of the limited partners' limited liability
                                                             and (2) will not adversely affect the tax status of
                                                             the partnership, Pioneer USA or the other partners.
                                                             The limited partners of each partnership have no right
                                                             to participate in the management and control of the
                                                             partnership and have no voice in the partnership's
                                                             affairs except for some limited matters that may be
                                                             submitted to a vote of the limited partners under the
                                                             terms of the partnership agreement of the partnership.
                                                             See "Voting Rights and Amendments" below. Pioneer USA
                                                             is accountable as a fiduciary to each partnership.
----------------------------------------------------------------------------------------------------------------------

                                            VOTING RIGHTS AND AMENDMENTS

----------------------------------------------------------------------------------------------------------------------
Pioneer's certificate of incorporation provides that (1)     Generally, meetings of each partnership may be called
stockholders of Pioneer may act only at annual or special    by Pioneer USA or by limited partners owning at least
meetings of stockholders and not by written consent, (2)     10% of the outstanding limited partnership interests.
Pioneer will hold an annual meeting each calendar year at    The limited partners may conduct any partnership
which its stockholders will elect directors, (3) special     business at such meeting which is permitted under the
meetings of stockholders may be called only by the board     partnership agreement for such partnership and is
of directors, and (4) only business proposed by the board    specified in the notice of such meeting, but the
of directors may be considered at special meetings of        limited partners may not engage in any activity which
stockholders.                                                would be deemed taking part in the management or
                                                             control of the partnership's business.
----------------------------------------------------------------------------------------------------------------------




                                                       -70-
   80



                          SHARES                                              PARTNERSHIP INTERESTS

---------------------------------------------------------------------------------------------------------------------
                                                          
Most amendments to Pioneer's certificate of incorporation    Amendments to the partnership agreement of each
require the approval of the stockholders who own a           partnership generally require the approval by limited
majority of the outstanding shares of Pioneer common         partners holding a majority of outstanding limited
stock.  A number of fundamental amendments, however,         partnership interests in the partnership.  An amendment
require approval by a greater percentage of stockholders.    that has any of the following effects requires the
For example, any amendment to the following provisions       unanimous approval of Pioneer USA and the limited
requires the approval of two-thirds of the stockholders:     partners: (1) increases the liability or duties of any
(1) election of directors, (2) authority of the board of     of the partners, (2) changes the contributions required
directors, (3) stockholder meetings and (4) limitation on    of the partners, (3) provides for any reallocation of
the liability of directors.  Any amendment to the            profits, losses or deductions to the detriment of a
provision that prohibits action by the written consent of    partner, (4) establishes any new priority in one or
the stockholders in lieu of a meeting requires the           more partners as to the return of capital contributions
approval of 80% of the stockholders.  In addition, the       or as to profits, losses, deductions or distribution to
following actions require the approval of 80% of the         the detriment of a partner, or (5) causes the
stockholders and the approval of two-thirds of the           partnership to be taxed as a corporation.  Pioneer USA
disinterested stockholders:  (1) any merger, consolidation   may, in its sole discretion, adopt any of the following
or share exchange involving any person, other than Pioneer   amendments: (1) change the name of the partnership, (2)
or a subsidiary of Pioneer, who beneficially owns 10% or     change the location of the principal place of business
more of the outstanding voting securities of Pioneer,        of the partnership, (3) admit a new or substitute
which person we call a related party, (2) some sales,        limited partner, (4) modify its general partnership
leases, exchanges or similar transactions with related       interest as a result of a transfer of a portion of such
parties, (3) some issuances of securities to related         interest, (5) correct a typographical error, or (6) any
parties, (4) adoption of any plan or proposal for            other similar change where the Pioneer USA determines
liquidation of Pioneer initiated by related parties, or      that the amendment will not adversely affect the
(5) any series or combination of any of the actions          limited partners and Pioneer USA believes the amendment
described in clauses (1) through (4).                        is necessary or advisable to qualify the partnership
                                                             under the laws of a state in which it engages or
                                                             proposes to engage in business or to keep the
                                                             partnership from being treated as a corporation for
                                                             tax purposes.
----------------------------------------------------------------------------------------------------------------------

                                                  LIMITED LIABILITY

----------------------------------------------------------------------------------------------------------------------
A stockholder's liability will generally be limited to       Assuming the limited partners of a partnership do not take
such stockholder's contribution to Pioneer's capital.        part in the management or control of the business of such
Under Delaware law, Pioneer's stockholders will not be       partnership, a limited partner's liability is generally
liable for Pioneer's debts or obligations. The shares of     limited to the limited partner's contribution to the
Pioneer common stock offered by Pioneer under this           capital of the partnership and such limited partner's
document, upon issuance, will be fully paid and              share of assets and undistributed profits of the
nonassessable.                                               partnership. A limited partner will receive a return of
                                                             the limited partner's capital contribution to the
                                                             partnership to the extent that a distribution to the
                                                             limited partner reduces the limited partner's share of the
                                                             fair value of the partnership's net assets below the value
                                                             of the limited partner's unreturned capital
                                                             contributions. A substituted limited partner is subject
                                                             to the liabilities and obligations of the substituted
                                                             limited partner's assignor, except those liabilities of
                                                             which the substituted limited partner was unaware at the
                                                             time he became a substituted limited partner and which
                                                             could not be ascertained from the partnership agreement of
                                                             the partnership.
----------------------------------------------------------------------------------------------------------------------




                                                       -71-
   81



                          SHARES                                              PARTNERSHIP INTERESTS

---------------------------------------------------------------------------------------------------------------------

                                          BUSINESS ACTIVITIES AND FINANCING

----------------------------------------------------------------------------------------------------------------------
                                                          
Pioneer's mission is to provide its stockholders with        The business operations of each partnership have
superior investment returns through strategies that          consisted of the development and production of oil and
maximize Pioneer's long-term profitability and net asset     gas reserves.  Each partnership has expended its
values.  The strategies employed to achieve this mission     initial partnership capital, and additional properties
are anchored by Pioneer's long-lived Spraberry oil and gas   cannot be acquired.  Operations can be financed only
field and Hugoton and West Panhandle gas fields' reserves    through permitted borrowings, reinvestment of earnings
and production.  Underlying these fields are approximately   not distributed, permitted assessments, or permitted
67% of Pioneer's proved oil and gas reserves which have a    sales of assets.  Each partnership generally is
remaining productive life in excess of 40 years.  The        required to distribute to its partners all or
stable base of oil and gas production from these fields      substantially all its net cash flow from operations,
generates operating cash flows that allow Pioneer the        after provision for any reserves deemed appropriate by
financial flexibility to selectively reinvest capital:       Pioneer USA.

o    to develop and increase production from existing
     properties through low-risk development drilling
     activities;

o    to leverage cost containment opportunities to
     achieve operating and technical efficiencies; and

o    to pursue strategic acquisitions in Pioneer's core
     areas that will complement Pioneer's existing
     asset base and provide additional growth
     opportunities.

Pioneer also has the financial flexibility to use
portions of its operating cash flows:

o    to selectively expand into new geographic areas
     that feature producing properties and provide
     exploration or exploitation opportunities;

o    to invest in the personnel and technology
     necessary to increase Pioneer's exploration
     opportunities; and

o    to enhance liquidity.

This flexibility allows Pioneer to take advantage of
future exploration, development and acquisition
opportunities.

Pioneer may engage in any phase of the oil and gas
business and any other lawful business. Pioneer may
finance its operations and the acquisition of
additional properties through, among other things, the
issuance of additional shares of Pioneer common stock,
borrowings, and the reinvestment of earnings not
distributed to stockholders.

----------------------------------------------------------------------------------------------------------------------

                                                 FINANCIAL REPORTING

----------------------------------------------------------------------------------------------------------------------
Pioneer is subject to the reporting requirements of the      For a list of the partnerships that are subject to the
Securities Exchange Act of 1934.                             reporting requirements of the Securities Exchange Act
                                                             of 1934, see "Where You Can Find More Information" on
                                                             page 74. In addition, the partnership agreement of
                                                             each partnership requires that some reports be
                                                             delivered to the limited partners.
----------------------------------------------------------------------------------------------------------------------




                                                       -72-
   82



                          SHARES                                              PARTNERSHIP INTERESTS

---------------------------------------------------------------------------------------------------------------------

                                                   TAX INFORMATION

----------------------------------------------------------------------------------------------------------------------
                                                          
"Double taxation" at the corporate and stockholder levels    None of the partnerships is a taxable entity for
typically results when a corporation such as Pioneer earns   federal income tax purposes.  The partners of each
income and distributes that income to its stockholders in    partnership are required to take into account their pro
the form of dividends.  Stockholders will only recognize     rata share of the partnership's income, gains, losses,
income on amounts actually distributed by Pioneer.           and deductions, regardless of whether they receive any
Distributions made by Pioneer out of current or              cash distributions from the partnership.  Some partners
accumulated earnings and profits are taxed as dividend       may be entitled to percentage depletion.  A partner
income.  Distributions in excess of current or accumulated   will be required to recapture some deductions and
earnings and profits are treated as a non-taxable return     credits upon the sale of all or a portion of his
of basis to the extent of stockholders' adjusted basis in    partnership interests.
their shares, with the excess taxed as capital gain.

Dividends, if any, received by stockholders from             A partner's share of a partnership's income and loss
Pioneer generally will constitute portfolio income,          will be subject to the "passive activity" limitations.
and cannot be offset with losses from "passive               Under the passive activity rules, losses of a partner
activities." Losses and credits generated within             arising from his ownership of partnership interests
Pioneer do not pass through to the stockholders. After       may be used to offset passive income from another
the end of Pioneer's taxable year, stockholders will         passive investment and income of a partner arising
receive Form 1099-DIV to report their dividend income.       from his ownership of partnership interests may only
                                                             be offset with passive losses from another passive
                                                             investment. For a discussion of the tax consequences
                                                             associated with the merger of each partnership, see
                                                             "The Merger of Each Partnership -- Material U.S.
                                                             Federal Income Tax Consequences."
----------------------------------------------------------------------------------------------------------------------

                       DIVIDEND OR DISTRIBUTION POLICY AND PARTICIPATION IN PROFITS AND LOSSES

----------------------------------------------------------------------------------------------------------------------
The shares of Pioneer common stock constitute equity         For a description of the distribution policies of each
interests in Pioneer.  Each stockholder will be entitled     partnership, see "Risk Factors -- Risks Associated with
to his pro rata share of the dividends made with respect     an Investment in Pioneer -- Pioneer Might Not Declare
to the Pioneer common stock.  The dividends payable to the   Dividends." The average quarterly cash distributions by
stockholders are not fixed in amount and are only paid if,   each partnership for 1999, 2000 and the year-to-date in
as and when declared by Pioneer's board of directors.        2001 are set forth in Table 7 of Appendix A. For a
Dividends payable with respect to the shares of Pioneer      description of the provisions of the partnership
common stock depend upon the performance of Pioneer.         agreement of each partnership governing the allocation
                                                             of costs and revenues among the partnership's partners,
                                                             see Table 9 of Appendix A.
----------------------------------------------------------------------------------------------------------------------



                                  LEGAL MATTERS

     Vinson & Elkins L.L.P., counsel to Pioneer, will pass upon the validity of
the Pioneer common stock to be issued upon the merger of each partnership. The
limited partners' special legal counsel,          , Dallas, Texas, will deliver
the legal opinion referred to in "The Merger of Each Partnership -- Legal
Opinion for Limited Partners" on page 43 of this document. That special counsel
may rely as to matters of law of jurisdictions other than the United States and
the State of Texas on the opinion of counsel in such other jurisdictions.

           INDEPENDENT AUDITORS AND INDEPENDENT PETROLEUM CONSULTANTS

     The consolidated financial statements of Pioneer appearing in its Annual
Report (Form 10-K) for the year ended December 31, 2000, have been audited by
Ernst & Young LLP, independent auditors, as set forth in their report, which is
incorporated by reference into this document. Such consolidated financial
statements are incorporated by reference in reliance upon such report given on
the authority of such firm as experts in accounting and auditing.



                                      -73-
   83
 The financial statements of each partnership listed on pages 4 and 5 of this
document at December 31, 2000 and 1999 and for each of the three years in the
period ended December 31, 2000 have been audited by Ernst & Young LLP,
independent auditors, as set forth in their reports included in the supplemental
information to this document for each partnership. Such financial statements are
included in the supplemental information of each partnership in reliance upon
such reports given on the authority of such firm as experts in accounting and
auditing.

     Williamson Petroleum Consultants, Inc., independent petroleum consultants,
prepared the estimates of each partnership's proved reserves as of December 31,
2000 and the present value of the estimated future net revenues from those
estimated reserves included in the summary reserve report included in this
document and such summary reserve report and estimates are included in this
document in reliance upon their report given upon their authority as experts on
the matters covered by the summary reserve report.

                       WHERE YOU CAN FIND MORE INFORMATION

     Pioneer and each of the 25 partnerships listed below file annual, quarterly
and special reports, proxy statements and other information with the Securities
and Exchange Commission:


                                                          
Parker & Parsley 82-I, Ltd.                                  Parker & Parsley Producing Properties 87-B, Ltd.
Parker & Parsley 82-II, Ltd.                                 Parker & Parsley 88-A, L.P.
Parker & Parsley 83-A, Ltd.                                  Parker & Parsley 88-B, L.P.
Parker & Parsley 83-B, Ltd.                                  Parker & Parsley Producing Properties 88-A, L.P.
Parker & Parsley 84-A, Ltd.                                  Parker & Parsley 89-A, L.P.
Parker & Parsley 85-A, Ltd.                                  Parker & Parsley 90-A L.P.
Parker & Parsley 85-B, Ltd.                                  Parker & Parsley 90-B Conv., L.P.
Parker & Parsley 86-A, Ltd.                                  Parker & Parsley 90-B, L.P.
Parker & Parsley 86-B, Ltd.                                  Parker & Parsley 90-C Conv., L.P.
Parker & Parsley 86-C, Ltd.                                  Parker & Parsley 90-C, L.P.
Parker & Parsley 87-A, Ltd.                                  Parker & Parsley 91-A, L.P.
Parker & Parsley 87-B, Ltd.                                  Parker & Parsley 91-B, L.P.
Parker & Parsley Producing Properties 87-A, Ltd.


You may read and copy any reports, statements or other information that Pioneer
or any reporting partnership files at the SEC's public reference room at 450
Fifth Street, N.W., Washington, D.C. 20549, or at the SEC's public reference
rooms at 7 World Trade Center, Suite 1300 New York, New York 10048 and at 500
West Madison Street, Suite 1400, Chicago, Illinois 60661. Copies of these
materials may also be obtained from the SEC at prescribed rates by writing to
the Public Reference Section of the Securities and Exchange Commission, 450
Fifth Street, N.W., Washington, D.C. 20549. Please call the SEC at
1-800-SEC-0330 for further information on the public reference rooms. Pioneer's
and each reporting partnership's filings with the SEC are also available to the
public from commercial document retrieval services and at the web site
maintained by the SEC at http://www.sec.gov.

     Pioneer's common stock is listed on the New York Stock Exchange and the
Toronto Stock Exchange, under the symbol "PXD." Pioneer's reports and other
information filed with the SEC can also be inspected at the offices of the New
York Stock Exchange and the Toronto Stock Exchange.

     Pioneer filed a registration statement on Form S-4 to register with the SEC
Pioneer common stock to be issued to the limited partners of each participating
partnership. This document is a part of that registration statement and
constitutes the prospectus of Pioneer in addition to being the proxy statement
of each partnership. As allowed by SEC rules, this document does not contain all
the information you can find in the registration statement or the exhibits to
the registration statement.

     The SEC allows Pioneer to incorporate by reference information into this
document, which means that Pioneer can disclose important information to you by
referring you to another document filed separately with the SEC. The information
incorporated by reference is deemed to be part of this document, except for any
information superseded by information in this document. This document
incorporates by reference the documents set forth below that Pioneer has
previously filed with the SEC and that contain important information about
Pioneer and its finances:

     o    Annual Report on Form 10-K for the year ended December 31, 2000

     o    Quarterly Report on Form 10-Q for the three months ended March 31,
          2001

     o    Proxy Statement on Schedule 14A for 2001 Annual Meeting filed April 2,
          2001

     o    The description of Pioneer common stock contained in Pioneer's
          registration statement on Form 8-A filed on August 5, 1997, as amended
          by Form 8-A/A filed on August 8, 1997.



                                      -74-
   84

     Pioneer is also incorporating by reference additional documents that it
files with the SEC between the date of this document and the date of the special
meeting for each partnership.

     The supplement to this document for each partnership contains financial
information for the partnership. The information supplement for each partnership
constitutes an integral part of this document. Please carefully read the
supplement for each partnership in which you are a limited partner.

     Pioneer has supplied all information contained or incorporated by reference
in this document relating to Pioneer, and each partnership has supplied all the
information contained in this document relating to the partnership.

     You can obtain any of the documents incorporated by reference through
Pioneer or the SEC. Documents incorporated by reference are available from
Pioneer without charge. Exhibits to the documents will not be sent, however,
unless those exhibits have specifically been incorporated by reference as
exhibits in this document. Limited partners of each partnership may obtain
documents incorporated by reference in this document by requesting them in
writing or by telephone at the following address:

                      Pioneer Natural Resources Company
                      1400 Williams Square West
                      5205 North O'Connor Blvd.
                      Irving, Texas 77039
                      Telephone: (972) 444-9001
                      Attention: Investor Relations

     IF YOU WOULD LIKE TO REQUEST DOCUMENTS FROM PIONEER OR ANY PARTNERSHIP IN
WHICH YOU OWN AN INTEREST, PLEASE DO SO BY               , 2001 [INSERT 5TH
BUSINESS DAY BEFORE MEETING] TO RECEIVE THEM BEFORE THE SPECIAL MEETING FOR THE
PARTNERSHIP.

     You should rely only on the information contained or incorporated by
reference in this document to vote on the merger of each partnership in which
you own an interest. We have not authorized anyone to give any information that
is different from what is contained in this document. This document is dated
              , 2001. You should not assume that the information contained in
this document is accurate as of any date other than that date, and neither the
mailing of this document to you nor the issuance of Pioneer common stock and the
payment of cash in the merger of each partnership shall create an implication to
the contrary.


                                      -75-
   85

                         COMMONLY USED OIL AND GAS TERMS

     The definitions set forth below shall apply to the indicated terms as used
in this document. All volumes of natural gas referred to herein are stated at
the legal pressure base of the state or area where the reserves exist and at 60
degrees Fahrenheit and in most instances are rounded to the nearest major
multiple.

     "Bbl" means a standard barrel of 42 U.S. gallons and represents the basic
unit for measuring the production of crude oil, natural gas liquids and
condensate.

     "Bcf" means one billion cubic feet under prescribed conditions of pressure
and temperature and represents the basic unit for measuring the production of
natural gas.

     "BOE" means a barrel-of-oil-equivalent and is a customary convention used
in the United States to express oil and gas volumes on a comparable basis. It is
determined on the basis of the estimated relative energy content of natural gas
to oil, being approximately six Mcf of natural gas per Bbl of oil.

     "BTU" means British thermal unit.

     "Mbbl" means one thousand Bbls.

     "MBOE" means one thousand BOEs.

     "Mcf" means one thousand cubic feet under prescribed conditions of pressure
and temperature and represents the basic unit for measuring the production of
natural gas.

     "MMBbl" means one million Bbls.

     "MMcf" means one million cubic feet under prescribed conditions of pressure
and temperature and represents the basic unit for measuring the production of
natural gas.

     "NGLs" means natural gas liquids.

     "proved reserves" means the estimated quantities of crude oil, natural gas,
and natural gas liquids which geological and engineering data demonstrate with
reasonable certainty to be recoverable in future years from known reservoirs
under existing economic and operating conditions, i.e., prices and costs as of
the date the estimate is made. Prices include consideration of changes in
existing prices provided only by contractual arrangements, but not on
escalations based upon future conditions.

              (i) Reservoirs are considered proved if economic producibility is
     supported by either actual production or conclusive formation test. The
     area of a reservoir considered proved includes (A) that portion delineated
     by drilling and defined by gas-oil and/or oil-water contacts, if any; and
     (B) the immediately adjoining portions not yet drilled, but which can be
     reasonably judged as economically productive on the basis of available
     geological and engineering data. In the absence of information on fluid
     contacts, the lowest known structural occurrence of hydrocarbons controls
     the power proved limit of the reservoir.

              (ii) Reserves which can be produced economically through
     application of improved recovery techniques (such as fluid injection) are
     included in the "proved" classification when successful testing by a pilot
     project, or the operation of an installed program in the reservoir,
     provides support for the engineering analysis on which the project or
     program was based.

              (iii) Estimates of proved reserves do not include the following:
     (A) oil that may become available from known reservoirs but is classified
     separately as "indicated additional reserves"; (B) crude oil, natural gas,
     and natural gas liquids, the recovery of which is subject to reasonable
     doubt because of uncertainty as to geology, reservoir characteristics, or
     economic factors; (C) crude oil, natural gas, and natural gas liquids, that
     may occur in undrilled prospects; and (D) crude oil, natural gas, and
     natural gas liquids, that may be recovered from oil shales, coal, gilsonite
     and other such sources.


                                      -76-
   86

                        PIONEER NATURAL RESOURCES COMPANY

                UNAUDITED PRO FORMA COMBINED FINANCIAL STATEMENTS

INTRODUCTORY STATEMENTS

     The unaudited pro forma combined financial statements of Pioneer have been
prepared to give effect to Pioneer's offer to acquire 46 limited partnerships
(collectively, the "Combined Partnerships") that Pioneer USA serves as the sole
or managing general partner.

     The unaudited pro forma combined statements of operations of Pioneer for
the year ended December 31, 2000 has been prepared to give effect to the
acquisition of the Combined Partnerships as if it had occurred on January 1,
2000.

     The unaudited pro forma combined balance sheet of Pioneer for the year
ended December 31, 2000 has been prepared to give effect to the acquisition of
the Combined Partnerships as if it had occurred on December 31, 2000.

     The unaudited pro forma combined financial statements included herein are
not necessarily indicative of the results that might have occurred had the
transaction taken place on the date that is assumed for the pro forma
presentations and are not intended to be a projection of future results. Future
results may vary significantly from the results reflected in the accompanying
unaudited pro forma combined financial statements because of normal production
declines, changes in product prices, future acquisitions and divestitures,
future development and exploration activities, and other factors.

     The following unaudited pro forma combined financial statements should be
read in conjunction with the Consolidated Financial Statements (and the related
notes) of Pioneer included in the Annual Report on Form 10-K for the year ended
December 31, 2000 and the historical financial statements of each partnership in
which you own an interest contained in the supplement to this document for the
partnership.


                                      P-1
   87

                        PIONEER NATURAL RESOURCES COMPANY

                   UNAUDITED PRO FORMA COMBINED BALANCE SHEET
                             AS OF DECEMBER 31, 2000
                        (IN THOUSANDS, EXCEPT SHARE DATA)




                                     ASSETS
                                                                                 COMBINED           PRO FORMA           PRO FORMA
                                                              PIONEER          PARTNERSHIPS        ADJUSTMENTS           PIONEER
                                                            -----------        ------------        ------------        -----------
                                                                                                           
Current assets:
  Cash and cash equivalents ........................        $    26,159         $     5,528         $                  $    31,687
  Accounts receivable:
    Trade, net .....................................            123,497               7,856                                131,353
    Affiliates .....................................              2,157                  --                (725)(b)          1,432
  Inventories ......................................             14,842                  --                                 14,842
  Deferred income taxes ............................              4,800                  --                                  4,800
  Other current assets .............................             19,936                  --                                 19,936
                                                            -----------         -----------                            -----------
     Total current assets ..........................            191,391              13,384                                204,050
                                                            -----------         -----------                            -----------

Property, plant and equipment, at cost:
  Oil and gas properties, using the successful
    efforts method of accounting:
      Proved properties ............................          3,187,889             357,514            (265,798)(a)      3,279,605
      Unproved properties ..........................            229,205                  --                                229,205
  Accumulated depletion, depreciation and
    amortization ...................................           (902,139)           (310,329)            310,329 (a)       (902,139)
                                                            -----------         -----------                            -----------
                                                              2,514,955              47,185                              2,606,671
                                                            -----------         -----------                            -----------

Deferred income taxes ..............................             84,400                  --                                 84,400
Other property and equipment, net ..................             25,624                  --                                 25,624
Other assets, net ..................................            138,065                  --                                138,065
                                                            -----------         -----------                            -----------
                                                            $ 2,954,435         $    60,569                            $ 3,058,810
                                                            ===========         ===========                            ===========

                        LIABILITIES AND STOCKHOLDERS' EQUITY
Current liabilities:
  Accounts payable:
    Trade ..........................................        $    96,646         $        --         $                  $    96,646
    Affiliates .....................................              5,629                 725                (725)(b)          5,629
  Interest payable .................................             38,142                  --                                 38,142
  Other current liabilities:
    Derivative obligations .........................             24,957                  --                                 24,957
    Other ..........................................             51,140                  --                                 51,140
                                                            -----------         -----------                            -----------
     Total current liabilities .....................            216,514                 725                                216,514
                                                            -----------         -----------                            -----------

Long-term debt, less current maturities ............          1,578,776                  --              27,543 (a)      1,606,319
Other noncurrent liabilities .......................            225,740                  --                                225,740
Deferred income taxes ..............................             28,500                  --                                 28,500
Partners' capital ..................................                 --              59,844              59,844 (a)             --
Stockholders' equity:
  Preferred stock ..................................                 --                  --                                     --
  Common stock .....................................              1,013                  --                  43 (a)          1,056
  Additional paid-in capital .......................          2,352,608                  --              76,789 (a)      2,429,397
  Treasury stock ...................................            (37,682)                 --                                (37,682)
  Accumulated deficit ..............................         (1,422,703)                 --                             (1,422,703)
  Accumulated other comprehensive income:
    Unrealized gain on available for sale
     securities ....................................              8,154                  --                                  8,154
    Cumulative translation adjustment ..............              3,515                  --                                  3,515
                                                            -----------         -----------                            -----------
     Total stockholders' equity and
      partners' capital ............................            904,905              59,844                                981,737
Commitments and contingencies ......................
                                                            -----------         -----------                            -----------

                                                            $ 2,954,435         $    60,569                            $ 3,058,810
                                                            ===========         ===========                            ===========


         The accompanying notes are an integral part of these unaudited
                    pro forma combined financial statements.


                                      P-2
   88

                        PIONEER NATURAL RESOURCES COMPANY

              UNAUDITED PRO FORMA COMBINED STATEMENT OF OPERATIONS
                          YEAR ENDED DECEMBER 31, 2000
                      (IN THOUSANDS, EXCEPT PER SHARE DATA)



                                                                                COMBINED          PRO FORMA           PRO FORMA
                                                                 PIONEER      PARTNERSHIPS       ADJUSTMENTS           PIONEER
                                                                --------      ------------      ------------          ----------
                                                                                                          
Revenues:
  Oil and gas ..........................................        $852,738        $ 52,013        $     (3,369)(c)        $901,382
  Interest and other ...................................          25,775             484                 (28)(c)          26,231
  Gain on disposition of assets, net ...................          34,184             247                  (6)(c)          34,425
                                                                --------        --------                                --------
                                                                 912,697          52,744                                 962,038
                                                                --------        --------                                --------
Cost and expenses:
  Oil and gas production ...............................         189,265          19,958              (1,392)(c)
                                                                                                      (5,655)(d)         202,176
  Depletion, depreciation and
  amortization .........................................         214,938           3,236               3,768 (e)         221,942
  Impairment of oil and gas properties .................              --             663                (663)(f)              --
  Exploration and abandonments .........................          87,550              72                  (3)(c)          87,619
  General and administrative ...........................          33,262           1,599                (110)(c)          40,406
                                                                                                       5,655 (d)
  Interest .............................................         161,952              --               1,829 (g)         163,781
  Other ................................................          67,231              --                                  67,231
                                                                --------        --------                                --------
                                                                 754,198          25,528                                 783,155
                                                                --------        --------                                --------

Income from continuing operations before
   income taxes ........................................         158,499          27,216                                 178,883
Income tax benefit .....................................           6,000              --                  -- (h)           6,000
                                                                --------        --------                                --------
Income from continuing operations ......................        $164,499        $ 27,216                                $184,883
                                                                ========        ========                                ========

Income from continuing operations per
   common share:
    Basic ..............................................        $   1.65                                                $   1.78
                                                                ========                                                ========
    Diluted ............................................        $   1.65                                                $   1.78
                                                                ========                                                ========
Weighted average basic shares
  outstanding ..........................................          99,378                               4,268 (i)         103,646
                                                                ========                                                ========



                  See accompanying notes to unaudited pro forma
                         combined financial statements.


                                      P-3
   89

                        PIONEER NATURAL RESOURCES COMPANY

                      NOTES TO UNAUDITED PRO FORMA COMBINED
                              FINANCIAL STATEMENTS
                                DECEMBER 31, 2000


NOTE 1. BASIS OF PRESENTATION

     The unaudited pro forma combined financial information of Pioneer Natural
Resources Company ("Pioneer") has been prepared to give effect to Pioneer's
offer to acquire 46 limited partnerships (collectively, the "Combined
Partnerships") that Pioneer USA serves as the sole or managing general partner.
The unaudited pro forma combined statement of operations for the year ended
December 31, 2000 is presented as if the acquisition of the Combined
Partnerships occurred on January 1, 2000. The unaudited pro forma combined
balance sheet as of December 31, 2000 has been prepared to give effect to the
acquisition of the Combined Partnerships as if it had occurred on December 31,
2000.

     Following is a description of the individual columns included in these
unaudited pro forma combined financial statements:

     Pioneer - Represents the consolidated balance sheet and consolidated
  statement of operations of Pioneer Natural Resources Company as of December
  31, 2000 and for the year ended December 31, 2000, respectively.

     Combined Partnerships - Represents the combined balance sheet of the 46
  limited partnerships as of December 31, 2000 and the combined statement of
  operations of such limited partnerships for the year ended December 31, 2000.

NOTE 2. PRO FORMA ADJUSTMENTS

     Following are descriptions of the pro forma adjustments used in the
preparation of the accompanying unaudited pro forma combined financial
statements:

  (a)  To record the acquisition of the Combined Partnerships for cash
       consideration of $27.5 million, including transaction costs, and Pioneer
       common stock having a market value of $76.8 million using the purchase
       method of accounting. The allocation of the purchase price to the
       acquired assets and liabilities is preliminary and, therefore, subject to
       change. Any future adjustments to the allocation of the purchase price
       are not anticipated to be material to Pioneer's financial statements.

  (b)  To eliminate affiliate receivables and affiliate payables between Pioneer
       and the Combined Partnerships.

  (c)  To eliminate Pioneer's proportionate share of the Combined Partnerships
       that is already reflected in Pioneer's consolidated statement of
       operations for the year ended December 31, 2000.

  (d)  To reclassify the Combined Partnership's share of operating overhead
       charged by Pioneer that was recorded by the Combined Partnerships as an
       increase in lease operating expenses and by Pioneer as a reduction to
       general and administrative expense.

  (e)  To adjust depreciation, depletion and amortization expense for the basis
       allocated to the oil and gas properties acquired and accounted for using
       the successful efforts method of accounting.

  (f)  To eliminate the Combined Partnerships impairment of oil and gas
       properties that would not occur on a pro forma basis with Pioneer.

  (g)  To increase interest expense for the year ended December 31, 2000 to
       reflect the increase in outstanding bank indebtedness as a result of
       funding the acquisition of the Combined Partnerships through additional
       borrowings under Pioneer's revolving credit facility. The adjustments for
       the year ended December 31, 2000 are based on Pioneer's average annual
       interest rate of 6.64 percent incurred on bank indebtedness.


                                      P-4
   90

                        PIONEER NATURAL RESOURCES COMPANY

                      NOTES TO UNAUDITED PRO FORMA COMBINED
                              FINANCIAL STATEMENTS
                                DECEMBER 31, 2000

  (h)   Pioneer has unused net operating loss carryovers in the United States
        that could be used to offset any incremental earnings of the Combined
        Partnerships. Accordingly, no pro forma adjustment was recorded for
        additional income tax expense. See Note 3. below.

  (i)   To adjust the weighted average shares outstanding for the acquisition of
        the Combined Partnerships.

NOTE 3. INCOME TAXES

     Pioneer will account for income taxes in accordance with the provisions of
Statement of Financial Accounting Standards No. 109, "Accounting for Income
Taxes". In accordance therewith, Pioneer will prepare separate tax calculations
for each tax jurisdiction in which Pioneer will be subject to income taxes.
Pioneer has unused net operating loss carryovers and alternative minimum tax net
operating loss carryovers that would be utilized to reduce incremental United
States income taxes that would otherwise be incurred as a result of pro forma
pre-tax earnings of the Combined Partnerships. Accordingly, Pioneer has not
recognized incremental income tax expense in the accompanying unaudited pro
forma combined statement of operations for the year ended December 31, 2000.

NOTE 4. OIL AND GAS RESERVE DATA

     The following unaudited pro forma supplemental information regarding the
oil and gas activities of Pioneer is presented pursuant to the disclosure
requirements promulgated by the Securities and Exchange Commission and Statement
of Financial Accounting Standards No. 69, "Disclosures About Oil and Gas
Producing Activities". The pro forma combined reserve information is presented
as if the acquisition of the Combined Partnerships had occurred on January 1,
2000. Information for oil and NGLs are presented in barrels (Bbls) and for gas
in thousands of cubic feet (Mcf).

     Pioneer emphasizes that reserve estimates are inherently imprecise and
subject to revision and that estimates of new discoveries are more imprecise
than those of producing oil and gas properties. Accordingly, the estimates are
expected to change as future information becomes available and such changes
could be significant.


                                      P-5
   91

                        PIONEER NATURAL RESOURCES COMPANY

                      NOTES TO UNAUDITED PRO FORMA COMBINED
                              FINANCIAL STATEMENTS
                                DECEMBER 31, 2000

QUANTITIES OF OIL AND GAS RESERVES

     Set forth below is a pro forma summary of the changes in the net quantities
of oil, NGL and natural gas reserves for the year ended December 31, 2000.



                                                             OIL
                                                           & NGLS               GAS
                                                           (Mbbls)             (Mmcf)              MBOE
                                                          ----------         ----------         ----------
                                                                                       
TOTAL PROVED RESERVES:

UNITED STATES
Balance, January 1 ...............................           290,683          1,365,530            518,271
Revisions of previous estimates ..................            18,704             54,518             27,790
Purchases of minerals-in-place ...................             1,237             28,071              5,916
New discoveries and extensions ...................             4,819             66,486             15,900
Production .......................................           (18,571)           (86,206)           (32,939)
Sales of minerals-in-place .......................              (743)           (35,054)            (6,586)
                                                          ----------         ----------         ----------
Balance, December 31 .............................           296,129          1,393,345            528,352

ARGENTINA
Balance, January 1 ...............................            29,797            415,620             99,067
Revisions of previous estimates ..................             1,411            (15,558)            (1,182)
Purchases of minerals-in-place ...................                --                 --                 --
New discoveries and extensions ...................             8,066             43,914             15,385
Production .......................................            (3,431)           (35,694)            (9,380)
Sales of minerals-in-place .......................                --                 --                 --
                                                          ----------         ----------         ----------
Balance, December 31 .............................            35,843            408,282            103,890

CANADA
Balance, January 1 ...............................             3,970            145,251             28,179
Revisions of previous estimates ..................               429            (10,013)            (1,240)
Purchases of minerals-in-place ...................               140              7,768              1,435
New discoveries and extensions ...................               138              6,132              1,160
Production .......................................              (611)           (16,219)            (3,315)
Sales of minerals-in-place .......................                --                 --                 --
                                                          ----------         ----------         ----------
Balance, December 31 .............................             4,066            132,919             26,219

SOUTH AFRICA
Balance, January 1 ...............................                --                 --                 --
New discoveries and extensions ...................             5,552                 --              5,552
                                                          ----------         ----------         ----------
Balance, December 31 .............................             5,552                 --              5,552

TOTAL
Balance, January 1 ...............................           324,450          1,926,401            645,517
Revisions of previous estimates ..................            20,544             28,947             25,368
Purchases of minerals-in-place ...................             1,377             35,839              7,351
New discoveries and extensions ...................            18,575            116,532             37,997
Production .......................................           (22,613)          (138,119)           (45,634)
Sales of minerals-in-place .......................              (743)           (35,054)            (6,586)
                                                          ----------         ----------         ----------
Balance, December 31 .............................           341,590          1,934,546            664,013
                                                          ==========         ==========         ==========

PROVED DEVELOPED RESERVES:
  United States ..................................           241,253          1,169,664            436,198
  Argentina ......................................            22,931            358,124             82,618
  Canada .........................................             2,598             61,210             12,800
                                                          ----------         ----------         ----------
    January 1 ....................................           266,782          1,588,998            531,616
                                                          ==========         ==========         ==========

  United States ..................................           236,249          1,120,610            423,018
  Argentina ......................................            22,679            345,281             80,226
  Canada .........................................             2,930             80,953             16,422
                                                          ----------         ----------         ----------
    December 31 ..................................           261,858          1,546,844            519,666
                                                          ==========         ==========         ==========



                                      P-6
   92

                        PIONEER NATURAL RESOURCES COMPANY

                      NOTES TO UNAUDITED PRO FORMA COMBINED
                              FINANCIAL STATEMENTS
                                DECEMBER 31, 2000

STANDARDIZED MEASURE OF DISCOUNTED FUTURE NET CASH FLOWS

     The pro forma standardized measure of discounted future net cash flow is
computed by applying year-end prices of oil and gas (with consideration of price
changes only to the extent provided by contractual arrangements) to the
estimated future production of oil and gas reserves less estimated future
expenditures (based on year-end costs) to be incurred in developing and
producing the proved reserves discounted using a rate of 10 percent per year to
reflect the estimated timing of the future cash flows. Future income taxes are
calculated by comparing undiscounted future cash flows to the tax basis of oil
and gas properties plus available carryforwards and credits and applying the
current tax rate to the difference.



                                                                       DECEMBER 31, 2000
                                                                       -----------------
                                                                         (IN THOUSANDS)
                                                                    
UNITED STATES
Oil and gas producing activities:
  Future cash inflows ...........................................        $ 19,615,577
  Future production costs .......................................          (5,290,990)
  Future development costs ......................................            (479,290)
  Future income tax expenses ....................................          (3,945,569)
                                                                         ------------
                                                                            9,899,728
  10% annual discount factor ....................................          (4,991,172)
                                                                         ------------
  Standardized measure of discounted future net cash flows ......        $  4,908,556
                                                                         ============

ARGENTINA
Oil and gas producing activities:
  Future cash inflows ...........................................        $  1,183,652
  Future production costs .......................................            (215,853)
  Future development costs ......................................            (114,606)
  Future income tax expenses ....................................             (81,705)
                                                                         ------------
                                                                              771,488
  10% annual discount factor ....................................            (264,126)
                                                                         ------------
  Standardized measure of discounted future net cash flows ......        $    507,362
                                                                         ============

CANADA
Oil and gas producing activities:
  Future cash inflows ...........................................        $  1,029,007
  Future production costs .......................................            (104,189)
  Future development costs ......................................             (35,443)
  Future income tax expenses ....................................            (306,399)
                                                                         ------------
                                                                              582,976
  10% annual discount factor ....................................            (168,441)
                                                                         ------------
  Standardized measure of discounted future net cash flows ......        $    414,535
                                                                         ============

SOUTH AFRICA
Oil and gas producing activities:
  Future cash inflows ...........................................        $    126,134
  Future production costs .......................................             (65,232)
  Future development costs ......................................             (47,970)
  Future income tax expenses ....................................                  --
                                                                         ------------
                                                                               12,932
  10% annual discount factor ....................................              (5,782)
                                                                         ------------
  Standardized measure of discounted future net cash flows ......        $      7,150
                                                                         ============

TOTAL
Oil and gas producing activities:
  Future cash inflows ...........................................        $ 21,954,370
  Future production costs .......................................          (5,676,264)
  Future development costs ......................................            (677,309)
  Future income tax expenses ....................................          (4,333,673)
                                                                         ------------
                                                                           11,267,124
  10% annual discount factor ....................................          (5,429,521)
                                                                         ------------
  Standardized measure of discounted future net cash flows ......        $  5,837,603
                                                                         ============



                                      P-7
   93
                        PIONEER NATURAL RESOURCES COMPANY

                      NOTES TO UNAUDITED PRO FORMA COMBINED
                              FINANCIAL STATEMENTS
                                DECEMBER 31, 2000


CHANGES RELATING TO THE PRO FORMA STANDARDIZED MEASURE OF DISCOUNTED FUTURE NET
CASH FLOWS

     The principal sources of the change in the pro forma combined standardized
measure of discounted future net cash flows for the year ended December 31, 2000
are as follows (in thousands):


                                                       
Oil and gas sales, net of production costs                $  (699,206)
Net changes in prices and production costs                  3,920,249
Extension and discoveries                                     525,361
Sales of minerals-in-place                                    (72,624)
Purchases of mineral-in-place                                 187,097
Revisions of estimated future development costs               (99,384)
Revisions of previous quantity estimates                      329,124
Accretion of discount                                         313,281
Changes in production rates, timing and other                (270,400)
                                                          -----------
Change in present value of future net revenues              4,133,498
Net change in present value of future income taxes         (1,428,700)
                                                          -----------
                                                            2,704,798
Balance, beginning of year                                  3,132,805
                                                          -----------
Balance, end of year                                      $ 5,837,603
                                                          ===========



                                      P-8
   94
                                   APPENDIX A

                                       TO

                           PROXY STATEMENT/PROSPECTUS

                GENERAL INFORMATION RELATING TO EACH PARTNERSHIP


Table 1           Jurisdiction of Organization, Initial Subscription Price for
                  Each Unit, Initial Investment by Limited Partners and Number
                  of Limited Partners as of March 31, 2001

Table 2           Aggregate Merger Value as of March 31, 2001

Table 3           Merger Value Attributable to Partnership Interests of Limited
                  Partners Per $1,000 Investment as of March 31, 2001

Table 4           Ownership Percentage and Merger Value Attributable to
                  Nonmanaging General Partners Other Than Pioneer USA as of
                  March 31, 2001

Table 5           Ownership Percentage and Merger Value Attributable to Pioneer
                  USA in Its Capacities as General Partner, Nonmanaging General
                  Partner and Limited Partner as of March 31, 2001

Table 6           Voting Percentage and Initial Investment Owned by Pioneer USA
                  in Its Capacity as a Limited Partner as of March 31, 2001

Table 7           Historical Quarterly Partnership Distributions to the Limited
                  Partners Per $1,000 Investment from Inception through March
                  31, 2001

Table 8           Annual Repurchase Prices and Aggregate Annual Repurchase
                  Payments

Table 9           Participation in Costs and Revenues of Each Partnership

Table 10          Average Oil, Natural Gas Liquids and Gas Sales Prices and
                  Production Costs for the Three Months Ended March 31, 2001 and
                  2000 and the Years Ended December 31, 2000, 1999 and 1998

Table 11          Proved Reserves Attributable to Pioneer USA, Nonmanaging
                  General Partners and Limited Partners as of December 31, 2000

Table 12          Proved Reserves Attributable to Pioneer USA, Nonmanaging
                  General Partners and Limited Partners as of March 31, 2001

Table 13          Oil, Natural Gas Liquids and Gas Production for the Three
                  Months Ended March 31, 2001 and 2000 and the Years Ended
                  December 31, 2000, 1999 and 1998

Table 14          Productive Wells and Developed Acreage as of December 31, 2000

Table 15          Recent Trades of Partnership Interests Per $1,000 Investments
                  for the Three Months Ended March 31, 2001 and the Years Ended
                  December 31, 2000 and 1999


                                      A-1


   95
                                     TABLE 1

     JURISDICTION OF ORGANIZATION, INITIAL SUBSCRIPTION PRICE FOR EACH UNIT,
      INITIAL INVESTMENT BY LIMITED PARTNERS AND NUMBER OF LIMITED PARTNERS
                              AS OF MARCH 31, 2001



                                                                                                INITIAL
                                                                              INITIAL          INVESTMENT
                                                                           SUBSCRIPTION        BY LIMITED        NUMBER OF
                                                         JURISDICTION OF     PRICE FOR          PARTNERS          LIMITED
                                                          ORGANIZATION       EACH UNIT       (IN THOUSANDS)       PARTNERS
                                                         ---------------   -------------     --------------     ------------

                                                                                                    
PARKER & PARSLEY 81-I, LTD.                                  Texas          $      5,000      $      7,410               135
PARKER & PARSLEY 81-II, LTD.                                 Texas                 5,000             6,440               158
PARKER & PARSLEY 82-I, LTD.                                  Texas                 2,000            11,805               600
PARKER & PARSLEY 82-II, LTD.                                 Texas                 2,000            12,252               772
PARKER & PARSLEY 82-III, LTD.                                Texas                 2,000             6,882               422
PARKER & PARSLEY 83-A, LTD.                                  Texas                 1,000            19,505             1,273
PARKER & PARSLEY 83-B, LTD.                                  Texas                 1,000            23,370             1,379
PARKER & PARSLEY 84-A, LTD.                                  Texas                 1,000            19,435             1,268
PARKER & PARSLEY 85-A, LTD.                                  Texas                 1,000             9,613               820
PARKER & PARSLEY 85-B, LTD.                                  Texas                 1,000             7,988               717
PARKER & PARSLEY PRIVATE INVESTMENT 85-A, LTD.               Texas                40,000             5,000               107
PARKER & PARSLEY SELECTED 85 PRIVATE INVESTMENT, LTD.        Texas                40,000             4,690                79
PARKER & PARSLEY 86-A, LTD.                                  Texas                 1,000            10,131               962
PARKER & PARSLEY 86-B, LTD.                                  Texas                 1,000            17,208             1,409
PARKER & PARSLEY 86-C, LTD.                                  Texas                 1,000            19,317             1,332
PARKER & PARSLEY PRIVATE INVESTMENT 86, LTD.                 Texas                40,000             4,920               103
PARKER & PARSLEY 87-A CONV., LTD.                            Texas                 1,000             3,856               214
PARKER & PARSLEY 87-A, LTD.                                  Texas                 1,000            28,811             2,148
PARKER & PARSLEY 87-B CONV., LTD.                            Texas                 1,000             4,919               259
PARKER & PARSLEY 87-B, LTD.                                  Texas                 1,000            20,089             1,468
PARKER & PARSLEY PRODUCING PROPERTIES 87-A, LTD.             Texas                   500            12,213             1,104
PARKER & PARSLEY PRODUCING PROPERTIES 87-B, LTD.             Texas                   500             6,096               550
PARKER & PARSLEY PRIVATE INVESTMENT 87, LTD.                 Texas                40,000            10,480               197
PARKER & PARSLEY 88-A CONV., L.P.                           Delaware               1,000             3,793               236
PARKER & PARSLEY 88-A, L.P.                                 Delaware               1,000            12,935               981
PARKER & PARSLEY 88-B CONV., L.P.                           Delaware               1,000             3,636               240
PARKER & PARSLEY 88-B, L.P.                                 Delaware               1,000             8,954               690
PARKER & PARSLEY 88-C CONV., L.P.                           Delaware               1,000             3,411               221
PARKER & PARSLEY 88-C, L.P.                                 Delaware               1,000             2,431               191
PARKER & PARSLEY PRODUCING PROPERTIES 88-A, L.P.            Delaware                 500             5,611               507
PARKER & PARSLEY PRIVATE INVESTMENT 88, L.P.                Delaware              40,000             9,960               153
PARKER & PARSLEY 89-A CONV., L.P.                           Delaware               1,000             2,797               191
PARKER & PARSLEY 89-A, L.P.                                 Delaware               1,000             8,317               609
PARKER & PARSLEY 89-B CONV., L.P.                           Delaware               1,000             6,307               341
PARKER & PARSLEY 89-B, L.P.                                 Delaware               1,000             6,949               458
PARKER & PARSLEY PRIVATE INVESTMENT 89, L.P.                Delaware              40,000             7,060               129
PARKER & PARSLEY 90-A CONV., L.P.                           Delaware               1,000             2,359               139
PARKER & PARSLEY 90-A, L.P.                                 Delaware               1,000             6,811               525
PARKER & PARSLEY 90-B CONV., L.P.                           Delaware               1,000            11,897               665
PARKER & PARSLEY 90-B, L.P.                                 Delaware               1,000            32,264             2,201
PARKER & PARSLEY 90-C CONV., L.P.                           Delaware               1,000             7,531               505
PARKER & PARSLEY 90-C, L.P.                                 Delaware               1,000            12,107               901
PARKER & PARSLEY PRIVATE INVESTMENT 90, L.P.                Delaware              40,000            10,970               197
PARKER & PARSLEY 90 SPRABERRY PRIVATE DEV., L.P.            Delaware              40,000             5,200               107
PARKER & PARSLEY 91-A, L.P.                                 Delaware               1,000            11,620               724
PARKER & PARSLEY 91-B, L.P.                                 Delaware               1,000            11,249               677
                                                                                                                ------------
                      TOTAL                                                                                           29,064
                                                                                                                ============





                                      A-2
   96



                                     TABLE 2

                             AGGREGATE MERGER VALUE
                              AS OF MARCH 31, 2001




                                                                            NONMANAGING
                                                                              GENERAL          LIMITED
                                                         PIONEER USA(a)      PARTNERS(b)      PARTNERS(c)          TOTAL
                                                         --------------     ------------      ------------      ------------

                                                                                                    
PARKER & PARSLEY 81-I, LTD.                               $    224,965      $     16,195      $    624,540      $    865,700
PARKER & PARSLEY 81-II, LTD.                                   145,382             5,948           478,519           629,849
PARKER & PARSLEY 82-I, LTD.                                    394,878            13,776           862,667         1,271,321
PARKER & PARSLEY 82-II, LTD.                                   404,903            12,591         1,159,842         1,577,336
PARKER & PARSLEY 82-III, LTD.                                  302,259             9,856           776,656         1,088,771
PARKER & PARSLEY 83-A, LTD.                                    922,900            36,351         2,611,053         3,570,304
PARKER & PARSLEY 83-B, LTD.                                  1,201,169            46,876         3,384,404         4,632,449
PARKER & PARSLEY 84-A, LTD.                                  1,236,369            54,433         3,684,435         4,975,237
PARKER & PARSLEY 85-A, LTD.                                     40,356                --         1,338,947         1,379,303
PARKER & PARSLEY 85-B, LTD.                                     19,800                --         1,132,138         1,151,938
PARKER & PARSLEY PRIVATE INVESTMENT 85-A, LTD.                  47,205                --         1,351,036         1,398,241
PARKER & PARSLEY SELECTED 85 PRIVATE INVESTMENT, LTD.           24,312                --           879,917           904,229
PARKER & PARSLEY 86-A, LTD.                                     23,089                --         1,697,382         1,720,471
PARKER & PARSLEY 86-B, LTD.                                     65,880                --         3,728,186         3,794,066
PARKER & PARSLEY 86-C, LTD.                                     41,460                --         3,129,450         3,170,910
PARKER & PARSLEY PRIVATE INVESTMENT 86, LTD.                    12,414                --         1,229,027         1,241,441
PARKER & PARSLEY 87-A CONV., LTD.                               13,894                --           717,899           731,793
PARKER & PARSLEY 87-A, LTD.                                     87,422                --         5,371,888         5,459,310
PARKER & PARSLEY 87-B CONV., LTD.                               11,819                --           972,088           983,907
PARKER & PARSLEY 87-B, LTD.                                     49,125                --         3,971,732         4,020,857
PARKER & PARSLEY PRODUCING PROPERTIES 87-A, LTD.                35,767                --         2,616,433         2,652,200
PARKER & PARSLEY PRODUCING PROPERTIES 87-B, LTD.                58,764                --         2,208,666         2,267,430
PARKER & PARSLEY PRIVATE INVESTMENT 87, LTD.                    27,958                --         2,767,809         2,795,767
PARKER & PARSLEY 88-A CONV., L.P.                               21,067                --           892,880           913,947
PARKER & PARSLEY 88-A, L.P.                                     72,602                --         3,051,312         3,123,914
PARKER & PARSLEY 88-B CONV., L.P.                               17,558                --         1,119,230         1,136,788
PARKER & PARSLEY 88-B, L.P.                                     57,127                --         2,744,178         2,801,305
PARKER & PARSLEY 88-C CONV., L.P.                               11,866                --           907,793           919,659
PARKER & PARSLEY 88-C, L.P.                                      7,833                --           642,988           650,821
PARKER & PARSLEY PRODUCING PROPERTIES 88-A, L.P.                33,093                --         1,927,264         1,960,357
PARKER & PARSLEY PRIVATE INVESTMENT 88, L.P.                    32,842                --         3,251,380         3,284,222
PARKER & PARSLEY 89-A CONV., L.P.                                8,987                --           889,670           898,657
PARKER & PARSLEY 89-A, L.P.                                     60,264                --         2,618,326         2,678,590
PARKER & PARSLEY 89-B CONV., L.P.                               23,144                --         1,738,245         1,761,389
PARKER & PARSLEY 89-B, L.P.                                     39,272                --         1,899,350         1,938,622
PARKER & PARSLEY PRIVATE INVESTMENT 89, L.P.                    28,935                --         1,824,803         1,853,738
PARKER & PARSLEY 90-A CONV., L.P.                                8,862                --           549,349           558,211
PARKER & PARSLEY 90-A, L.P.                                     50,684                --         1,565,155         1,615,839
PARKER & PARSLEY 90-B CONV., L.P.                               51,712                --         3,052,755         3,104,467
PARKER & PARSLEY 90-B, L.P.                                    105,775                --         8,324,640         8,430,415
PARKER & PARSLEY 90-C CONV., L.P.                               25,338                --         1,791,842         1,817,180
PARKER & PARSLEY 90-C, L.P.                                     35,557                --         2,877,105         2,912,662
PARKER & PARSLEY PRIVATE INVESTMENT 90, L.P.                    51,077                --         3,262,423         3,313,500
PARKER & PARSLEY 90 SPRABERRY PRIVATE DEV., L.P.                14,400                --         1,425,568         1,439,968
PARKER & PARSLEY 91-A, L.P.                                     62,309                --         4,441,741         4,504,050
PARKER & PARSLEY 91-B, L.P.                                     52,293                --         4,754,013         4,806,306


----------

(a)  Represents Pioneer USA's partnership interests in each partnership as: (1)
     the sole or managing general partner of the partnership; (2) a limited
     partner of the partnership; and (3) the sole general partner of each
     nonmanaging general partner. Pioneer USA will not receive any Pioneer
     common stock or cash payment for its partnership interests in any
     participating partnership. However, as a result of the merger of each
     participating partnership, Pioneer USA will own 100% of the properties of
     the partnership including properties attributable to its partnership
     interests in the partnership.

(b)  Represents four unaffiliated individuals' partnership interests as limited
     partners of each nonmanaging general partner. Excludes Pioneer USA's
     partnership interests as general partner of each nonmanaging general
     partner.

(c)  Represents the partnership interests of unaffiliated limited partners of
     each partnership. Excludes Pioneer USA's partnership interests as a limited
     partner of any partnership.





                                      A-3
   97
                                     TABLE 3

               MERGER VALUE ATTRIBUTABLE TO PARTNERSHIP INTERESTS
                               OF LIMITED PARTNERS
                              PER $1,000 INVESTMENT
                              AS OF MARCH 31, 2001



                                                                           LIMITED PARTNERS
                                                                         PER $1,000 INVESTMENT
                                                           ------------------------------------------------
                                                             RESERVE       WORKING CAPITAL       MERGER
                                                              VALUE             VALUE             VALUE
                                                           ------------      ------------      ------------

                                                                                      
PARKER & PARSLEY 81-I, LTD.                                $      79.20      $      10.31      $      89.51
PARKER & PARSLEY 81-II, LTD.                                      63.63             11.08             74.71
PARKER & PARSLEY 82-I, LTD.                                       71.29             10.58             81.87
PARKER & PARSLEY 82-II, LTD.                                      86.50             11.79             98.29
PARKER & PARSLEY 82-III, LTD.                                    107.54             12.47            120.01
PARKER & PARSLEY 83-A, LTD.                                      121.34             17.33            138.67
PARKER & PARSLEY 83-B, LTD.                                      130.87             19.59            150.46
PARKER & PARSLEY 84-A, LTD.                                      172.55             21.20            193.75
PARKER & PARSLEY 85-A, LTD.                                      125.01             17.04            142.05
PARKER & PARSLEY 85-B, LTD.                                      123.57             19.20            142.77
PARKER & PARSLEY PRIVATE INVESTMENT 85-A, LTD.                   249.82             27.03            276.85
PARKER & PARSLEY SELECTED 85 PRIVATE INVESTMENT, LTD.            168.86             22.01            190.87
PARKER & PARSLEY 86-A, LTD.                                      150.08             18.04            168.12
PARKER & PARSLEY 86-B, LTD.                                      191.52             26.76            218.28
PARKER & PARSLEY 86-C, LTD.                                      140.59             21.92            162.51
PARKER & PARSLEY PRIVATE INVESTMENT 86, LTD.                     221.21             28.59            249.80
PARKER & PARSLEY 87-A CONV., LTD.                                163.41             24.47            187.88
PARKER & PARSLEY 87-A, LTD.                                      162.88             24.71            187.59
PARKER & PARSLEY 87-B CONV., LTD.                                169.09             28.93            198.02
PARKER & PARSLEY 87-B, LTD.                                      169.09             29.06            198.15
PARKER & PARSLEY PRODUCING PROPERTIES 87-A, LTD.                 179.24             35.75            214.99
PARKER & PARSLEY PRODUCING PROPERTIES 87-B, LTD.                 336.93             31.33            368.26
PARKER & PARSLEY PRIVATE INVESTMENT 87, LTD.                     240.50             23.60            264.10
PARKER & PARSLEY 88-A CONV., L.P.                                208.54             30.01            238.55
PARKER & PARSLEY 88-A, L.P.                                      208.53             30.56            239.09
PARKER & PARSLEY 88-B CONV., L.P.                                273.58             35.94            309.52
PARKER & PARSLEY 88-B, L.P.                                      273.59             36.14            309.73
PARKER & PARSLEY 88-C CONV., L.P.                                234.36             32.56            266.92
PARKER & PARSLEY 88-C, L.P.                                      234.36             30.68            265.04
PARKER & PARSLEY PRODUCING PROPERTIES 88-A, L.P.                 282.67             63.21            345.88
PARKER & PARSLEY PRIVATE INVESTMENT 88, L.P.                     291.12             35.32            326.44
PARKER & PARSLEY 89-A CONV., L.P.                                281.55             36.53            318.08
PARKER & PARSLEY 89-A, L.P.                                      281.55             37.29            318.84
PARKER & PARSLEY 89-B CONV., L.P.                                242.33             34.15            276.48
PARKER & PARSLEY 89-B, L.P.                                      241.90             34.29            276.19
PARKER & PARSLEY PRIVATE INVESTMENT 89, L.P.                     231.26             28.68            259.94
PARKER & PARSLEY 90-A CONV., L.P.                                205.94             28.32            234.26
PARKER & PARSLEY 90-A, L.P.                                      205.95             28.92            234.87
PARKER & PARSLEY 90-B CONV., L.P.                                231.19             27.15            258.34
PARKER & PARSLEY 90-B, L.P.                                      231.34             27.34            258.68
PARKER & PARSLEY 90-C CONV., L.P.                                211.02             27.86            238.88
PARKER & PARSLEY 90-C, L.P.                                      211.02             27.15            238.17
PARKER & PARSLEY PRIVATE INVESTMENT 90, L.P.                     267.23             31.80            299.03
PARKER & PARSLEY 90 SPRABERRY PRIVATE DEV., L.P.                 250.03             24.12            274.15
PARKER & PARSLEY 91-A, L.P.                                      346.03             37.71            383.74
PARKER & PARSLEY 91-B, L.P.                                      382.48             40.51            422.99







                                      A-4
   98
                                     TABLE 4

              OWNERSHIP PERCENTAGE AND MERGER VALUE ATTRIBUTABLE TO
               NONMANAGING GENERAL PARTNERS OTHER THAN PIONEER USA
                              AS OF MARCH 31, 2001



                                           NONMANAGING GENERAL                    NONMANAGING
                                               PARTNERS(a)                 GENERAL PARTNERS' MERGER
                                  -------------------------------------    VALUE AS A PERCENTAGE OF
                                     OWNERSHIP         AGGREGATE MERGER      AGGREGATE MERGER VALUE
                                   PERCENTAGE(b)           VALUE(c)         FOR THE PARTNERSHIP(d)
                                  ---------------      ----------------    ------------------------

                                                                  
PARKER & PARSLEY 81-I, LTD.                  2.00%      $        16,195                      1.87%
PARKER & PARSLEY 81-II, LTD.                 1.00%                5,948                      0.94%
PARKER & PARSLEY 82-I, LTD.                  1.13%               13,776                      1.08%
PARKER & PARSLEY 82-II, LTD.                 0.84%               12,591                      0.80%
PARKER & PARSLEY 82-III, LTD.                0.94%                9,856                      0.91%
PARKER & PARSLEY 83-A, LTD.                  1.05%               36,351                      1.02%
PARKER & PARSLEY 83-B, LTD.                  1.05%               46,876                      1.01%
PARKER & PARSLEY 84-A, LTD.                  1.13%               54,433                      1.09%


---------------

(a)  Represents four unaffiliated individuals' partnership interests as limited
     partners of each nonmanaging general partner. Excludes Pioneer USA's
     partnership interests as general partner of each nonmanaging general
     partner.

(b)  Percentage owned is based upon ownership within the partnership as set
     forth in the revenue sharing provisions of the partnership agreement for
     the partnership.

(c)  See "Method of Determining Merger Value for Each Partnership and Amount of
     Pioneer Common Stock and Cash Offered."

(d)  Represents the dollar amount in the nonmanaging general partners' aggregate
     merger value column divided by the aggregate merger value for the
     partnership as set forth in Table 2.





                                      A-5
   99

                                     TABLE 5

                      OWNERSHIP PERCENTAGE AND MERGER VALUE
                ATTRIBUTABLE TO PIONEER USA IN ITS CAPACITIES AS
        GENERAL PARTNER, NONMANAGING GENERAL PARTNER AND LIMITED PARTNER
                              AS OF MARCH 31, 2001





                                                                                                         PIONEER USA'S
                                                                      PIONEER USA(a)                   MERGER VALUE AS A
                                                           -------------------------------------         PERCENTAGE OF
                                                              OWNERSHIP         AGGREGATE MERGER     AGGREGATE MERGER VALUE
                                                            PERCENTAGE(b)           VALUE(c)         FOR THE PARTNERSHIP(d)
                                                           ---------------      ----------------     ----------------------

                                                                                            
PARKER & PARSLEY 81-I, LTD.                                          27.38%      $       224,965                     25.99%
PARKER & PARSLEY 81-II, LTD.                                         24.41%              145,382                     23.08%
PARKER & PARSLEY 82-I, LTD.                                          31.92%              394,878                     31.06%
PARKER & PARSLEY 82-II, LTD.                                         26.92%              404,903                     25.67%
PARKER & PARSLEY 82-III, LTD.                                        28.54%              302,259                     27.76%
PARKER & PARSLEY 83-A, LTD.                                          26.55%              922,900                     25.85%
PARKER & PARSLEY 83-B, LTD.                                          26.76%            1,201,169                     25.93%
PARKER & PARSLEY 84-A, LTD.                                          25.49%            1,236,369                     24.85%
PARKER & PARSLEY 85-A, LTD.                                           2.93%               40,356                      2.93%
PARKER & PARSLEY 85-B, LTD.                                           1.72%               19,800                      1.72%
PARKER & PARSLEY PRIVATE INVESTMENT 85-A, LTD.                        3.38%               47,205                      3.38%
PARKER & PARSLEY SELECTED 85 PRIVATE INVESTMENT, LTD.                 2.69%               24,312                      2.69%
PARKER & PARSLEY 86-A, LTD.                                           1.34%               23,089                      1.34%
PARKER & PARSLEY 86-B, LTD.                                           1.74%               65,880                      1.74%
PARKER & PARSLEY 86-C, LTD.                                           1.31%               41,460                      1.31%
PARKER & PARSLEY PRIVATE INVESTMENT 86, LTD.                          1.00%               12,414                      1.00%
PARKER & PARSLEY 87-A CONV., LTD.                                     1.90%               13,894                      1.90%
PARKER & PARSLEY 87-A, LTD.                                           1.60%               87,422                      1.60%
PARKER & PARSLEY 87-B CONV., LTD.                                     1.20%               11,819                      1.20%
PARKER & PARSLEY 87-B, LTD.                                           1.22%               49,125                      1.22%
PARKER & PARSLEY PRODUCING PROPERTIES 87-A, LTD.                      1.35%               35,767                      1.35%
PARKER & PARSLEY PRODUCING PROPERTIES 87-B, LTD.                      2.59%               58,764                      2.59%
PARKER & PARSLEY PRIVATE INVESTMENT 87, LTD.                          1.00%               27,958                      1.00%
PARKER & PARSLEY 88-A CONV., L.P.                                     2.31%               21,067                      2.31%
PARKER & PARSLEY 88-A, L.P.                                           2.32%               72,602                      2.32%
PARKER & PARSLEY 88-B CONV., L.P.                                     1.54%               17,558                      1.54%
PARKER & PARSLEY 88-B, L.P.                                           2.04%               57,127                      2.04%
PARKER & PARSLEY 88-C CONV., L.P.                                     1.29%               11,866                      1.29%
PARKER & PARSLEY 88-C, L.P.                                           1.20%                7,833                      1.20%
PARKER & PARSLEY PRODUCING PROPERTIES 88-A, L.P.                      1.69%               33,093                      1.69%
PARKER & PARSLEY PRIVATE INVESTMENT 88, L.P.                          1.00%               32,842                      1.00%
PARKER & PARSLEY 89-A CONV., L.P.                                     1.00%                8,987                      1.00%
PARKER & PARSLEY 89-A, L.P.                                           2.25%               60,264                      2.25%
PARKER & PARSLEY 89-B CONV., L.P.                                     1.31%               23,144                      1.31%
PARKER & PARSLEY 89-B, L.P.                                           2.03%               39,272                      2.03%
PARKER & PARSLEY PRIVATE INVESTMENT 89, L.P.                          1.56%               28,935                      1.56%
PARKER & PARSLEY 90-A CONV., L.P.                                     1.59%                8,862                      1.59%
PARKER & PARSLEY 90-A, L.P.                                           3.14%               50,684                      3.14%
PARKER & PARSLEY 90-B CONV., L.P.                                     1.67%               51,712                      1.67%
PARKER & PARSLEY 90-B, L.P.                                           1.25%              105,775                      1.25%
PARKER & PARSLEY 90-C CONV., L.P.                                     1.39%               25,338                      1.39%
PARKER & PARSLEY 90-C, L.P.                                           1.22%               35,557                      1.22%
PARKER & PARSLEY PRIVATE INVESTMENT 90, L.P.                          1.54%               51,077                      1.54%
PARKER & PARSLEY 90 SPRABERRY PRIVATE DEV., L.P.                      1.00%               14,400                      1.00%
PARKER & PARSLEY 91-A, L.P.                                           1.38%               62,309                      1.38%
PARKER & PARSLEY 91-B, L.P.                                           1.09%               52,293                      1.09%


----------

(a)  Represents Pioneer USA's partnership interests in each partnership as: (1)
     the sole or managing general partner of the partnership; (2) a limited
     partner of the partnership; and (3) the sole general partner of each
     nonmanaging general partner. Pioneer USA will not receive any Pioneer
     common stock or cash payment for its partnership interests in any
     participating partnership. However, as a result of the merger of each
     participating partnership, Pioneer USA will own 100% of the properties of
     the partnership including properties attributable to its partnership
     interests in the partnership.

(b)  Percentage owned is based upon ownership within the partnership as set
     forth in the revenue sharing provisions of the partnership agreement for
     the partnership.

(c)  See "Method of Determining Merger Value for Each Partnership and Amount of
     Pioneer Common Stock and Cash Offered."

(d)  Represents the dollar amount in Pioneer USA's aggregate merger value column
     divided by the aggregate merger value for the partnership as set forth in
     Table 2.



                                      A-6
   100


                                     TABLE 6

          VOTING PERCENTAGE AND INITIAL INVESTMENT OWNED BY PIONEER USA
                      IN ITS CAPACITY AS A LIMITED PARTNER
                              AS OF MARCH 31, 2001



                                                                                   INITIAL INVESTMENT
                                                                 PIONEER USA            OWNED BY
                                                                    VOTING           PIONEER USA(d)
                                                               PERCENTAGE(a)(b)      (IN THOUSANDS)
                                                               ---------------     ------------------

                                                                             
PARKER & PARSLEY 81-I, LTD.                                               5.84%      $           433
PARKER & PARSLEY 81-II, LTD.                                              0.55%                   35
PARKER & PARSLEY 82-I, LTD.                                              10.73%                1,267
PARKER & PARSLEY 82-II, LTD.                                              3.69%                  452
PARKER & PARSLEY 82-III, LTD.                                             5.97%                  411
PARKER & PARSLEY 83-A, LTD.                                               3.47%                  676
PARKER & PARSLEY 83-B, LTD.                                               3.75%                  877
PARKER & PARSLEY 84-A, LTD.                                               2.16%                  419
PARKER & PARSLEY 85-A, LTD.(c)                                            0.00%                  187
PARKER & PARSLEY 85-B, LTD.(c)                                            0.00%                   58
PARKER & PARSLEY PRIVATE INVESTMENT 85-A, LTD.(c)                         0.00%                  120
PARKER & PARSLEY SELECTED 85 PRIVATE INVESTMENT, LTD.(c)                  0.00%                   80
PARKER & PARSLEY 86-A, LTD.                                               0.35%                   35
PARKER & PARSLEY 86-B, LTD.                                               0.74%                  128
PARKER & PARSLEY 86-C, LTD.                                               0.31%                   60
PARKER & PARSLEY PRIVATE INVESTMENT 86, LTD.(c)                           0.00%                   --
PARKER & PARSLEY 87-A CONV., LTD.                                         0.91%                   35
PARKER & PARSLEY 87-A, LTD.                                               0.61%                  175
PARKER & PARSLEY 87-B CONV., LTD.                                         0.20%                   10
PARKER & PARSLEY 87-B, LTD.                                               0.22%                   45
PARKER & PARSLEY PRODUCING PROPERTIES 87-A, LTD.                          0.35%                   43
PARKER & PARSLEY PRODUCING PROPERTIES 87-B, LTD.                          1.61%                   98
PARKER & PARSLEY PRIVATE INVESTMENT 87, LTD.                              0.00%                   --
PARKER & PARSLEY 88-A CONV., L.P.                                         1.32%                   50
PARKER & PARSLEY 88-A, L.P.                                               1.34%                  173
PARKER & PARSLEY 88-B CONV., L.P.                                         0.55%                   20
PARKER & PARSLEY 88-B, L.P.                                               1.05%                   94
PARKER & PARSLEY 88-C CONV., L.P.                                         0.29%                   10
PARKER & PARSLEY 88-C, L.P.                                               0.21%                    5
PARKER & PARSLEY PRODUCING PROPERTIES 88-A, L.P.                          0.70%                   39
PARKER & PARSLEY PRIVATE INVESTMENT 88, L.P.                              0.00%                   --
PARKER & PARSLEY 89-A CONV., L.P.                                         0.00%                   --
PARKER & PARSLEY 89-A, L.P.                                               1.26%                  105
PARKER & PARSLEY 89-B CONV., L.P.                                         0.32%                   20
PARKER & PARSLEY 89-B, L.P.                                               1.04%                   72
PARKER & PARSLEY PRIVATE INVESTMENT 89, L.P.                              0.57%                   40
PARKER & PARSLEY 90-A CONV., L.P.                                         0.59%                   14
PARKER & PARSLEY 90-A, L.P.                                               2.16%                  147
PARKER & PARSLEY 90-B CONV., L.P.                                         0.67%                   80
PARKER & PARSLEY 90-B, L.P.                                               0.26%                   83
PARKER & PARSLEY 90-C CONV., L.P.                                         0.40%                   30
PARKER & PARSLEY 90-C, L.P.                                               0.22%                   27
PARKER & PARSLEY PRIVATE INVESTMENT 90, L.P.                              0.55%                   60
PARKER & PARSLEY 90 SPRABERRY PRIVATE DEV., L.P.                          0.00%                   --
PARKER & PARSLEY 91-A, L.P.(c)                                            0.00%                   45
PARKER & PARSLEY 91-B, L.P.(c)                                            0.00%                   10


----------

(a)  Represents Pioneer USA's partnership interests in each partnership as a
     limited partner of the partnership. Pioneer USA will not receive any
     Pioneer common stock or cash payment for its partnership interests in any
     participating partnership. However, as a result of the merger of each
     participating partnership, Pioneer USA will own 100% of the properties of
     the partnership including properties attributable to its partnership
     interests in the partnership.

(b)  Represents percentage of limited partners' vote that Pioneer USA is
     entitled to vote. The voting percentage is calculated by dividing (1)
     Pioneer USA's ownership percentage of the partnership interests held as a
     limited partner, by (2) the percentage of partnership interests held by all
     limited partners in the partnership. For example, if the limited partners
     of a partnership represent 99% of the partnership and Pioneer USA owns 5%
     of the partnership interests as a limited partner in that partnership,
     Pioneer USA's voting percentage is 5.05%.

(c)  Pioneer USA is not entitled to vote partnership interests it holds as
     limited partner in this partnership.

(d)  Represents Pioneer USA's share of the initial investment by limited
     partners as shown on Table 1.




                                      A-7
   101






                                     TABLE 7

     HISTORICAL QUARTERLY PARTNERSHIP DISTRIBUTIONS TO THE LIMITED PARTNERS
                              PER $1,000 INVESTMENT
                      FROM INCEPTION THROUGH MARCH 31, 2001




                                                                               QUARTERLY DISTRIBUTIONS
                                                                                 TO LIMITED PARTNERS
                                                                               PER $1,000 INVESTMENT(a)
                                                        ------------------------------------------------------------------------
                                                         INCEPTION       QUARTER        QUARTER         QUARTER        QUARTER
                                                             TO           ENDED          ENDED           ENDED          ENDED
                                                          12/31/98        3/31/99       6/30/99         9/30/99        12/31/99
                                                        ------------   ------------   ------------   ------------   ------------

                                                                                                     
PARKER & PARSLEY 81-I, LTD.                             $     616.71   $       0.69   $         --   $       3.26   $       2.42
PARKER & PARSLEY 81-II, LTD.                                  808.37             --           0.35           1.26           2.71
PARKER & PARSLEY 82-I, LTD.                                   946.73           0.62           0.53           2.03           1.09
PARKER & PARSLEY 82-II, LTD.                                1,099.24           0.83             --           3.34           3.48
PARKER & PARSLEY 82-III, LTD.                                 924.16             --           1.69           2.92           5.07
PARKER & PARSLEY 83-A, LTD.                                 1,264.54             --             --           4.11           5.20
PARKER & PARSLEY 83-B, LTD.                                 1,458.60           0.96           1.79           4.89           6.30
PARKER & PARSLEY 84-A, LTD.                                 1,384.63           0.80           2.78           4.69           6.81
PARKER & PARSLEY 85-A, LTD.                                   678.73           0.83           1.49           4.98           9.55
PARKER & PARSLEY 85-B, LTD.                                   876.32             --           3.17           4.12           7.19
PARKER & PARSLEY PRIVATE INVESTMENT 85-A, LTD.                997.86           3.16           5.23           8.79          12.34
PARKER & PARSLEY SELECTED 85 PRIVATE INVESTMENT, LTD.         872.24           1.66             --           4.33           6.68
PARKER & PARSLEY 86-A, LTD.                                 1,279.93           0.79           2.23           6.38           5.82
PARKER & PARSLEY 86-B, LTD.                                 1,469.69           1.53           5.01           5.85           8.40
PARKER & PARSLEY 86-C, LTD.                                 1,401.81           0.82           2.38           1.77           7.30
PARKER & PARSLEY PRIVATE INVESTMENT 86, LTD.                1,525.50           1.23           1.22           5.88           5.44
PARKER & PARSLEY 87-A CONV., LTD.                           1,228.63           1.83           2.20           6.07           7.90
PARKER & PARSLEY 87-A, LTD.                                 1,228.70           1.83           2.20           6.07           7.90
PARKER & PARSLEY 87-B CONV., LTD.                           1,154.18           1.85           2.29           5.50           8.64
PARKER & PARSLEY 87-B, LTD.                                 1,154.25           1.85           2.29           5.50           8.64
PARKER & PARSLEY PRODUCING PROPERTIES 87-A, LTD.              889.65           1.49           0.89           6.21           9.75
PARKER & PARSLEY PRODUCING PROPERTIES 87-B, LTD.              956.04           3.97           1.02           8.98          13.99
PARKER & PARSLEY PRIVATE INVESTMENT 87, LTD.                1,457.32           2.20           4.09           8.56           9.55
PARKER & PARSLEY 88-A CONV., L.P.                             991.51           3.16           3.06           7.97          11.11
PARKER & PARSLEY 88-A, L.P.                                   991.61           3.16           3.06           7.97          11.11
PARKER & PARSLEY 88-B CONV., L.P.                             966.33           3.44           2.88           8.95          13.65
PARKER & PARSLEY 88-B, L.P.                                   966.37           3.44           2.88           8.95          13.65
PARKER & PARSLEY 88-C CONV., L.P.                             913.42           3.92           2.34           4.27          11.12
PARKER & PARSLEY 88-C, L.P.                                   913.01           3.92           2.34           4.27          11.12
PARKER & PARSLEY PRODUCING PROPERTIES 88-A, L.P.            1,075.69           6.51           4.02           7.58          11.34
PARKER & PARSLEY PRIVATE INVESTMENT 88, L.P.                1,031.07           3.57           6.66           8.39          12.47
PARKER & PARSLEY 89-A CONV., L.P.                             911.13           2.66           2.77           9.16          13.97
PARKER & PARSLEY 89-A, L.P.                                   911.19           2.66           2.77           9.16          13.97
PARKER & PARSLEY 89-B CONV., L.P.                             787.19           3.26           1.22           8.31          11.43
PARKER & PARSLEY 89-B, L.P.                                   787.20           3.26           1.22           8.31          11.43
PARKER & PARSLEY PRIVATE INVESTMENT 89, L.P.                  689.19           1.02           1.85           6.67           4.97
PARKER & PARSLEY 90-A CONV., L.P.                             784.83           3.18           1.68           8.12           9.46
PARKER & PARSLEY 90-A, L.P.                                   784.89           3.18           1.68           8.12           9.46
PARKER & PARSLEY 90-B CONV., L.P.                             600.45           2.10           1.80           7.47          11.46
PARKER & PARSLEY 90-B, L.P.                                   600.53           2.10           1.80           7.47          11.46
PARKER & PARSLEY 90-C CONV., L.P.                             537.51           0.95             --           6.26          10.83
PARKER & PARSLEY 90-C, L.P.                                   537.52           0.95             --           6.26          10.83
PARKER & PARSLEY PRIVATE INVESTMENT 90, L.P.                  673.63           2.14           3.11           5.62          12.23
PARKER & PARSLEY 90 SPRABERRY PRIVATE DEV., L.P.              632.08           3.71           3.09           6.40          13.59
PARKER & PARSLEY 91-A, L.P.                                   663.47           3.99           6.33          11.37          15.54
PARKER & PARSLEY 91-B, L.P.                                   526.98           3.95           7.05          13.55          18.24












                                                                             QUARTERLY DISTRIBUTIONS
                                                                                 TO LIMITED PARTNERS
                                                                             PER $1,000 INVESTMENT(a)
                                                       ---------------------------------------------------------------------
                                                        QUARTER     QUARTER     QUARTER     QUARTER     QUARTER    INCEPTION
                                                         ENDED       ENDED       ENDED       ENDED       ENDED        TO
                                                        3/31/00     6/30/00     9/30/00     12/31/00    3/31/01     3/31/01
                                                       ---------   ---------   ---------   ---------   ---------   ---------

                                                                                                 
PARKER & PARSLEY 81-I, LTD.                            $    4.24   $    5.53   $    4.53   $    5.41               $  642.79
PARKER & PARSLEY 81-II, LTD.                                2.01        2.99        5.00        5.97                  828.66
PARKER & PARSLEY 82-I, LTD.                                 3.93        4.77        6.70        4.06                  970.46
PARKER & PARSLEY 82-II, LTD.                                4.98        6.07        4.58        6.41                1,128.93
PARKER & PARSLEY 82-III, LTD.                               7.49        7.80        9.38        8.84                  967.35
PARKER & PARSLEY 83-A, LTD.                                 7.22        7.30        9.04       10.25                1,307.66
PARKER & PARSLEY 83-B, LTD.                                 8.70        9.68       11.28       10.66                1,512.86
PARKER & PARSLEY 84-A, LTD.                                 8.28       11.17       12.41       13.00                1,444.57
PARKER & PARSLEY 85-A, LTD.                                 7.09       11.26        9.94       10.41                  734.28
PARKER & PARSLEY 85-B, LTD.                                 7.95        9.04        9.26       12.47                  929.52
PARKER & PARSLEY PRIVATE INVESTMENT 85-A, LTD.             15.51       20.44       16.65       16.32                1,096.30
PARKER & PARSLEY SELECTED 85 PRIVATE INVESTMENT, LTD.       9.18       11.68       12.92       12.98                  931.67
PARKER & PARSLEY 86-A, LTD.                                 8.66       11.38       12.54       13.08                1,340.81
PARKER & PARSLEY 86-B, LTD.                                10.40       13.08       14.24       15.95                1,544.15
PARKER & PARSLEY 86-C, LTD.                                 8.35        9.67       12.04       12.45                1,456.59
PARKER & PARSLEY PRIVATE INVESTMENT 86, LTD.               14.07        9.36       17.03       15.11                1,594.84
PARKER & PARSLEY 87-A CONV., LTD.                          11.58       15.18       13.96       12.79                1,300.14
PARKER & PARSLEY 87-A, LTD.                                11.58       15.18       13.96       12.79                1,300.21
PARKER & PARSLEY 87-B CONV., LTD.                          10.07       12.58       13.53       12.84                1,221.48
PARKER & PARSLEY 87-B, LTD.                                10.07       12.58       13.53       12.84                1,221.55
PARKER & PARSLEY PRODUCING PROPERTIES 87-A, LTD.           10.92       13.50       12.12       14.11                  958.64
PARKER & PARSLEY PRODUCING PROPERTIES 87-B, LTD.           18.53       24.65       26.75       26.21                1,080.14
PARKER & PARSLEY PRIVATE INVESTMENT 87, LTD.               12.55       13.19       14.14       16.03                1,537.63
PARKER & PARSLEY 88-A CONV., L.P.                          12.48       15.67       17.33       16.95                1,079.24
PARKER & PARSLEY 88-A, L.P.                                12.48       15.67       17.33       16.95                1,079.34
PARKER & PARSLEY 88-B CONV., L.P.                          18.22       20.69       22.63       25.37                1,082.16
PARKER & PARSLEY 88-B, L.P.                                18.22       20.69       22.63       25.37                1,082.20
PARKER & PARSLEY 88-C CONV., L.P.                          16.38       18.34       19.83       21.01                1,010.63
PARKER & PARSLEY 88-C, L.P.                                16.38       18.34       19.83       21.01                1,010.22
PARKER & PARSLEY PRODUCING PROPERTIES 88-A, L.P.           21.95       19.09       18.82       21.76                1,186.76
PARKER & PARSLEY PRIVATE INVESTMENT 88, L.P.               15.99       19.23       23.09       21.51                1,141.98
PARKER & PARSLEY 89-A CONV., L.P.                          17.96       18.39       20.40       23.38                1,019.82
PARKER & PARSLEY 89-A, L.P.                                17.96       18.39       20.40       23.38                1,019.88
PARKER & PARSLEY 89-B CONV., L.P.                          14.28       18.94       20.23       20.99                  885.85
PARKER & PARSLEY 89-B, L.P.                                14.28       18.94       20.23       20.99                  885.86
PARKER & PARSLEY PRIVATE INVESTMENT 89, L.P.               13.32       15.00       16.66       20.33                  769.01
PARKER & PARSLEY 90-A CONV., L.P.                          12.70       14.52       17.43       19.18                  871.10
PARKER & PARSLEY 90-A, L.P.                                12.70       14.52       17.43       19.18                  871.16
PARKER & PARSLEY 90-B CONV., L.P.                          14.98       15.20       19.51       19.68                  692.65
PARKER & PARSLEY 90-B, L.P.                                14.98       15.20       19.51       19.68                  692.73
PARKER & PARSLEY 90-C CONV., L.P.                          13.62       14.90       19.01       17.84                  620.92
PARKER & PARSLEY 90-C, L.P.                                13.62       14.90       19.01       17.84                  620.93
PARKER & PARSLEY PRIVATE INVESTMENT 90, L.P.               15.05       18.11       20.29       25.10                  775.28
PARKER & PARSLEY 90 SPRABERRY PRIVATE DEV., L.P.           16.68       13.98       14.00       13.98                  717.51
PARKER & PARSLEY 91-A, L.P.                                20.76       23.19       26.03       30.05                  800.73
PARKER & PARSLEY 91-B, L.P.                                21.87       26.88       33.92       35.07                  687.51



----------

(a)  Past cash distributions to limited partners are not necessarily indicative
     of future cash distributions. Limited partners should not assume that any
     nonparticipating partnership will continue to make cash distributions at
     levels similar to those shown. See "The Merger of Each Partnership -
     Distribution of Pioneer Common Stock and Cash Payment."





                                      A-8
   102


                                     TABLE 8

        ANNUAL REPURCHASE PRICES AND AGGREGATE ANNUAL REPURCHASE PAYMENTS



                                            2001                          2000                           1999
                                  -------------------------     -------------------------     -------------------------
                                  REPURCHASE     AGGREGATE      REPURCHASE     AGGREGATE      REPURCHASE     AGGREGATE
                                    PRICE          ANNUAL         PRICE          ANNUAL         PRICE          ANNUAL
                                  PER $1,000     REPURCHASE     PER $1,000     REPURCHASE     PER $1,000     REPURCHASE
                                  INVESTMENT      PAYMENTS      INVESTMENT      PAYMENTS      INVESTMENT      PAYMENTS
                                  ----------     ----------     ----------     ----------     ----------     ----------

                                                                                           
PARKER & PARSLEY 82-I, LTD.       $   137.97            (a)     $    71.89     $    4,745     $     7.52     $       94
PARKER & PARSLEY 82-II, LTD.          133.72            (a)         102.38          1,024          26.17            131
PARKER & PARSLEY 82-III, LTD.         150.59            (a)         109.73          1,097          12.17            284
PARKER & PARSLEY 83-A, LTD.           196.67            (a)         137.59          9,494          27.05            541
PARKER & PARSLEY 83-B, LTD.           210.15            (a)         153.89          3,078          43.46             --
PARKER & PARSLEY 84-A, LTD.           267.03            (a)         175.78          7,031          45.72          1,143
                                                                               ----------                    ----------
                                                                               $   26,469                    $    2,193
                                                                               ==========                    ==========


----------

(a)  Payments will not be made until the second quarter of 2001.




                                      A-9
   103


                                     TABLE 9

                       PARTICIPATION IN COSTS AND REVENUES
                               OF EACH PARTNERSHIP




                                                                  CAPITAL COSTS                     REVENUES AND EXPENSES
                                                       ------------------------------------   ------------------------------------
                                                                   NONMANAGING                            NONMANAGING
                                                        GENERAL      GENERAL      LIMITED      GENERAL      GENERAL      LIMITED
                                                       PARTNER(a)  PARTNERS(a)  PARTNERS(a)   PARTNER(a)  PARTNERS(a)  PARTNERS(a)
                                                       ----------  -----------  -----------   ----------  -----------  -----------

                                                                                                     
PARKER & PARSLEY 81-I, LTD.                                    8%           2%          90%          20%           5%          75%
PARKER & PARSLEY 81-II, LTD.                                   8%           2%          90%          20%           5%          75%
PARKER & PARSLEY 82-I, LTD.                                    8%           2%          90%          20%           5%          75%
PARKER & PARSLEY 82-II, LTD.                                   8%           2%          90%          20%           5%          75%
PARKER & PARSLEY 82-III, LTD.                                  8%           2%          90%          20%           5%          75%
PARKER & PARSLEY 83-A, LTD.(b)                                 8%           2%          90%          20%           5%          75%
PARKER & PARSLEY 83-B, LTD.(b)                                 8%           2%          90%          20%           5%          75%
PARKER & PARSLEY 84-A, LTD.(b)                                 8%           2%          90%          20%           5%          75%
PARKER & PARSLEY 85-A, LTD.                                    1%           --          99%           1%           --          99%
PARKER & PARSLEY 85-B, LTD.                                    1%           --          99%           1%           --          99%
PARKER & PARSLEY PRIVATE INVESTMENT 85-A, LTD.                 1%           --          99%           1%           --          99%
PARKER & PARSLEY SELECTED 85 PRIVATE INVESTMENT, LTD.          1%           --          99%           1%           --          99%
PARKER & PARSLEY 86-A, LTD.                                    1%           --          99%           1%           --          99%
PARKER & PARSLEY 86-B, LTD.                                    1%           --          99%           1%           --          99%
PARKER & PARSLEY 86-C, LTD.                                    1%           --          99%           1%           --          99%
PARKER & PARSLEY PRIVATE INVESTMENT 86, LTD.                   1%           --          99%           1%           --          99%
PARKER & PARSLEY 87-A CONV., LTD.                              1%           --          99%           1%           --          99%
PARKER & PARSLEY 87-A, LTD.                                    1%           --          99%           1%           --          99%
PARKER & PARSLEY 87-B CONV., LTD.                              1%           --          99%           1%           --          99%
PARKER & PARSLEY 87-B, LTD.                                    1%           --          99%           1%           --          99%
PARKER & PARSLEY PRODUCING PROPERTIES 87-A, LTD.               1%           --          99%           1%           --          99%
PARKER & PARSLEY PRODUCING PROPERTIES 87-B, LTD.               1%           --          99%           1%           --          99%
PARKER & PARSLEY PRIVATE INVESTMENT 87, LTD.                   1%           --          99%           1%           --          99%
PARKER & PARSLEY 88-A CONV., L.P.                              1%           --          99%           1%           --          99%
PARKER & PARSLEY 88-A, L.P.                                    1%           --          99%           1%           --          99%
PARKER & PARSLEY 88-B CONV., L.P.                              1%           --          99%           1%           --          99%
PARKER & PARSLEY 88-B, L.P.                                    1%           --          99%           1%           --          99%
PARKER & PARSLEY 88-C CONV., L.P.                              1%           --          99%           1%           --          99%
PARKER & PARSLEY 88-C, L.P.                                    1%           --          99%           1%           --          99%
PARKER & PARSLEY PRODUCING PROPERTIES 88-A, L.P.               1%           --          99%           1%           --          99%
PARKER & PARSLEY PRIVATE INVESTMENT 88, L.P.                   1%           --          99%           1%           --          99%
PARKER & PARSLEY 89-A CONV., L.P.                              1%           --          99%           1%           --          99%
PARKER & PARSLEY 89-A, L.P.                                    1%           --          99%           1%           --          99%
PARKER & PARSLEY 89-B CONV., L.P.                              1%           --          99%           1%           --          99%
PARKER & PARSLEY 89-B, L.P.                                    1%           --          99%           1%           --          99%
PARKER & PARSLEY PRIVATE INVESTMENT 89, L.P.                   1%           --          99%           1%           --          99%
PARKER & PARSLEY 90-A CONV., L.P.                              1%           --          99%           1%           --          99%
PARKER & PARSLEY 90-A, L.P.                                    1%           --          99%           1%           --          99%
PARKER & PARSLEY 90-B CONV., L.P.                              1%           --          99%           1%           --          99%
PARKER & PARSLEY 90-B, L.P.                                    1%           --          99%           1%           --          99%
PARKER & PARSLEY 90-C CONV., L.P.                              1%           --          99%           1%           --          99%
PARKER & PARSLEY 90-C, L.P.                                    1%           --          99%           1%           --          99%
PARKER & PARSLEY PRIVATE INVESTMENT 90, L.P.                   1%           --          99%           1%           --          99%
PARKER & PARSLEY 90 SPRABERRY PRIVATE DEV., L.P.               1%           --          99%           1%           --          99%
PARKER & PARSLEY 91-A, L.P.                                    1%           --          99%           1%           --          99%
PARKER & PARSLEY 91-B, L.P.                                    1%           --          99%           1%           --          99%


--------------

(a)  These percentages represent the sharing ownerships as set forth in the
     prospectus for each partnership. Includes Pioneer USA's partnership
     interests in each partnership as: (1) the sole or managing general partner
     of the partnership; (2) a limited partner of the partnership; and (3) the
     sole general partner of each nonmanaging general partner. Pioneer USA will
     not receive any Pioneer common stock or cash payment for its partnership
     interests in any participating partnership.

(b)  Incremental direct costs 100% to limited partners.




                                      A-10
   104

                                    TABLE 10

   AVERAGE OIL, NATURAL GAS LIQUIDS AND GAS SALES PRICES AND PRODUCTION COSTS
     FOR THE THREE MONTHS ENDED MARCH 31, 2001 AND 2000 AND THE YEARS ENDED
                        DECEMBER 31, 2000, 1999 AND 1998




                                                                            AVERAGE SALES PRICE
                                                       --------------------------------------------------------------
                                                                              OIL (PER BBL)
                                                       --------------------------------------------------------------
                                                        FOR THE THREE MONTHS              FOR THE YEAR ENDED
                                                           ENDED MARCH 31,                    DECEMBER 31,
                                                       -----------------------   ------------------------------------
                                                           2001        2000          2000         1999         1998
                                                       -----------------------   ------------------------------------

                                                                                            
PARKER & PARSLEY 81-I, LTD.                                         $    27.16   $    29.26   $    16.94   $    13.33
PARKER & PARSLEY 81-II, LTD.                                             27.34        29.26        16.67        13.16
PARKER & PARSLEY 82-I, LTD.                                              27.23        29.39        16.61        13.32
PARKER & PARSLEY 82-II, LTD.                                             27.27        29.47        17.08        13.14
PARKER & PARSLEY 82-III, LTD.                                            27.64        29.67        17.13        13.31
PARKER & PARSLEY 83-A, LTD.                                              27.44        29.54        16.96        13.34
PARKER & PARSLEY 83-B, LTD.                                              27.66        29.69        17.18        13.30
PARKER & PARSLEY 84-A, LTD.                                              27.61        29.55        17.36        13.30
PARKER & PARSLEY 85-A, LTD.                                              27.40        29.38        17.11        13.27
PARKER & PARSLEY 85-B, LTD.                                              28.65        30.02        18.07        13.30
PARKER & PARSLEY PRIVATE INVESTMENT 85-A, LTD.                           27.36        30.19        16.91        13.20
PARKER & PARSLEY SELECTED 85 PRIVATE INVESTMENT, LTD.                    27.34        29.59        17.27        13.44
PARKER & PARSLEY 86-A, LTD.                                              27.46        28.87        17.00        13.32
PARKER & PARSLEY 86-B, LTD.                                              27.60        29.45        17.18        13.08
PARKER & PARSLEY 86-C, LTD.                                              27.56        29.43        17.18        13.26
PARKER & PARSLEY PRIVATE INVESTMENT 86, LTD.                             27.55        29.45        17.34        13.34
PARKER & PARSLEY 87-A CONV., LTD.                                        27.18        29.46        17.06        13.22
PARKER & PARSLEY 87-A, LTD.                                              27.18        29.46        17.06        13.22
PARKER & PARSLEY 87-B CONV., LTD.                                        27.69        29.31        16.71        13.17
PARKER & PARSLEY 87-B, LTD.                                              27.69        29.31        16.71        13.17
PARKER & PARSLEY PRODUCING PROPERTIES 87-A, LTD.                         27.47        29.34        16.80        13.04
PARKER & PARSLEY PRODUCING PROPERTIES 87-B, LTD.                         27.54        29.36        17.44        13.05
PARKER & PARSLEY PRIVATE INVESTMENT 87, LTD.                             27.10        29.56        16.82        13.05
PARKER & PARSLEY 88-A CONV., L.P.                                        27.90        29.28        16.91        13.59
PARKER & PARSLEY 88-A, L.P.                                              27.90        29.28        16.91        13.59
PARKER & PARSLEY 88-B CONV., L.P.                                        26.41        29.29        17.17        13.24
PARKER & PARSLEY 88-B, L.P.                                              26.41        29.29        17.17        13.24
PARKER & PARSLEY 88-C CONV., L.P.                                        26.37        29.33        17.24        13.30
PARKER & PARSLEY 88-C, L.P.                                              26.37        29.33        17.24        13.30
PARKER & PARSLEY PRODUCING PROPERTIES 88-A, L.P.                         27.98        29.44        16.82        13.14
PARKER & PARSLEY PRIVATE INVESTMENT 88, L.P.                             27.22        29.45        17.01        13.31
PARKER & PARSLEY 89-A CONV., L.P.                                        27.48        29.59        17.11        13.23
PARKER & PARSLEY 89-A, L.P.                                              27.48        29.59        17.11        13.23
PARKER & PARSLEY 89-B CONV., L.P.                                        27.13        29.21        16.96        13.26
PARKER & PARSLEY 89-B, L.P.                                              27.13        29.21        16.96        13.26
PARKER & PARSLEY PRIVATE INVESTMENT 89, L.P.                             26.78        29.00        17.06        13.28
PARKER & PARSLEY 90-A CONV., L.P.                                        27.38        29.32        17.06        13.20
PARKER & PARSLEY 90-A, L.P.                                              27.38        29.32        17.06        13.20
PARKER & PARSLEY 90-B CONV., L.P.                                        27.70        29.23        17.23        13.12
PARKER & PARSLEY 90-B, L.P.                                              27.70        29.23        17.23        13.12
PARKER & PARSLEY 90-C CONV., L.P.                                        27.16        29.34        17.13        13.24
PARKER & PARSLEY 90-C, L.P.                                              27.16        29.34        17.13        13.24
PARKER & PARSLEY PRIVATE INVESTMENT 90, L.P.                             27.27        29.35        17.30        13.19
PARKER & PARSLEY 90 SPRABERRY PRIVATE DEV., L.P.                         26.83        29.17        17.04        13.06
PARKER & PARSLEY 91-A, L.P.                                              27.88        29.90        17.57        13.15
PARKER & PARSLEY 91-B, L.P.                                              28.53        30.09        17.90        13.33









                                                                             AVERAGE SALES PRICE
                                                        --------------------------------------------------------------
                                                                               NGL (PER BBL)
                                                        --------------------------------------------------------------
                                                         FOR THE THREE MONTHS               FOR THE YEAR ENDED
                                                             ENDED MARCH 31,                    DECEMBER 31,
                                                        -----------------------   ------------------------------------
                                                            2001       2000           2000         1999        1998
                                                        -----------------------   ------------------------------------

                                                                                             
PARKER & PARSLEY 81-I, LTD.                                          $    14.58   $    14.60   $     9.22   $     6.40
PARKER & PARSLEY 81-II, LTD.                                              17.54        15.59         8.70         6.73
PARKER & PARSLEY 82-I, LTD.                                               12.67        14.44         8.96         7.20
PARKER & PARSLEY 82-II, LTD.                                              13.18        15.01         9.80         6.93
PARKER & PARSLEY 82-III, LTD.                                             12.20        13.86         9.13         6.42
PARKER & PARSLEY 83-A, LTD.                                               14.18        15.58         9.42         6.49
PARKER & PARSLEY 83-B, LTD.                                               13.48        15.47        10.00         6.79
PARKER & PARSLEY 84-A, LTD.                                               12.70        14.00         9.03         6.08
PARKER & PARSLEY 85-A, LTD.                                               12.16        14.20         9.71         6.51
PARKER & PARSLEY 85-B, LTD.                                               14.41        15.96        10.10         6.95
PARKER & PARSLEY PRIVATE INVESTMENT 85-A, LTD.                            13.27        15.22         9.95         6.49
PARKER & PARSLEY SELECTED 85 PRIVATE INVESTMENT, LTD.                     13.50        15.52        10.49         6.99
PARKER & PARSLEY 86-A, LTD.                                               13.90        14.94         9.63         6.53
PARKER & PARSLEY 86-B, LTD.                                               13.37        15.00         9.39         6.80
PARKER & PARSLEY 86-C, LTD.                                               13.64        15.06         9.27         6.46
PARKER & PARSLEY PRIVATE INVESTMENT 86, LTD.                              13.33        15.01         9.27         6.69
PARKER & PARSLEY 87-A CONV., LTD.                                         15.12        16.01         9.81         6.76
PARKER & PARSLEY 87-A, LTD.                                               15.12        16.01         9.81         6.76
PARKER & PARSLEY 87-B CONV., LTD.                                         15.18        16.90         9.73         6.82
PARKER & PARSLEY 87-B, LTD.                                               15.18        16.90         9.73         6.82
PARKER & PARSLEY PRODUCING PROPERTIES 87-A, LTD.                          11.93        12.12         7.32         5.46
PARKER & PARSLEY PRODUCING PROPERTIES 87-B, LTD.                          14.93        16.68        10.32         6.58
PARKER & PARSLEY PRIVATE INVESTMENT 87, LTD.                              14.77        16.17         9.41         6.55
PARKER & PARSLEY 88-A CONV., L.P.                                         13.93        15.30         9.30         6.57
PARKER & PARSLEY 88-A, L.P.                                               13.93        15.30         9.30         6.57
PARKER & PARSLEY 88-B CONV., L.P.                                         14.34        16.02        10.03         6.91
PARKER & PARSLEY 88-B, L.P.                                               14.34        16.02        10.03         6.91
PARKER & PARSLEY 88-C CONV., L.P.                                         14.26        15.83        10.42         6.94
PARKER & PARSLEY 88-C, L.P.                                               14.26        15.83        10.42         6.94
PARKER & PARSLEY PRODUCING PROPERTIES 88-A, L.P.                          13.03        14.28         9.18         6.31
PARKER & PARSLEY PRIVATE INVESTMENT 88, L.P.                              14.02        15.61         9.32         6.79
PARKER & PARSLEY 89-A CONV., L.P.                                         13.84        15.42         9.54         6.95
PARKER & PARSLEY 89-A, L.P.                                               13.84        15.42         9.54         6.95
PARKER & PARSLEY 89-B CONV., L.P.                                         14.82        15.56         9.57         6.94
PARKER & PARSLEY 89-B, L.P.                                               14.82        15.56         9.57         6.94
PARKER & PARSLEY PRIVATE INVESTMENT 89, L.P.                              11.59        14.86         8.69         6.57
PARKER & PARSLEY 90-A CONV., L.P.                                         13.78        15.62         9.58         7.02
PARKER & PARSLEY 90-A, L.P.                                               13.78        15.62         9.58         7.02
PARKER & PARSLEY 90-B CONV., L.P.                                         13.89        15.45         9.49         6.60
PARKER & PARSLEY 90-B, L.P.                                               13.89        15.45         9.49         6.60
PARKER & PARSLEY 90-C CONV., L.P.                                         12.95        14.91         9.31         6.80
PARKER & PARSLEY 90-C, L.P.                                               12.95        14.91         9.31         6.80
PARKER & PARSLEY PRIVATE INVESTMENT 90, L.P.                              14.06        15.82         9.46         6.77
PARKER & PARSLEY 90 SPRABERRY PRIVATE DEV., L.P.                          14.49        15.56         9.70         6.89
PARKER & PARSLEY 91-A, L.P.                                               13.65        14.94         9.34         6.44
PARKER & PARSLEY 91-B, L.P.                                               15.13        16.50        10.15         6.79









                                                                             AVERAGE SALES PRICE
                                                        --------------------------------------------------------------
                                                                               GAS (PER MCF)
                                                        --------------------------------------------------------------
                                                         FOR THE THREE MONTHS               FOR THE YEAR ENDED
                                                             ENDED MARCH 31,                    DECEMBER 31,
                                                        -----------------------   ------------------------------------
                                                            2001        2000         2000          1999         1998
                                                        -----------------------   ------------------------------------

                                                                                             
PARKER & PARSLEY 81-I, LTD.                                          $     1.83   $     3.22   $     1.78   $     1.78
PARKER & PARSLEY 81-II, LTD.                                               1.26         3.07         1.82         1.80
PARKER & PARSLEY 82-I, LTD.                                                2.33         3.29         1.95         1.82
PARKER & PARSLEY 82-II, LTD.                                               1.90         2.98         1.79         1.64
PARKER & PARSLEY 82-III, LTD.                                              1.60         2.54         1.65         1.53
PARKER & PARSLEY 83-A, LTD.                                                1.76         3.02         1.78         1.60
PARKER & PARSLEY 83-B, LTD.                                                1.76         2.83         1.66         1.54
PARKER & PARSLEY 84-A, LTD.                                                1.54         2.49         1.47         1.33
PARKER & PARSLEY 85-A, LTD.                                                1.71         2.66         1.70         1.56
PARKER & PARSLEY 85-B, LTD.                                                1.84         2.92         1.72         1.58
PARKER & PARSLEY PRIVATE INVESTMENT 85-A, LTD.                             1.58         2.65         1.54         1.41
PARKER & PARSLEY SELECTED 85 PRIVATE INVESTMENT, LTD.                      1.70         2.77         1.67         1.56
PARKER & PARSLEY 86-A, LTD.                                                1.63         2.56         1.57         1.46
PARKER & PARSLEY 86-B, LTD.                                                1.76         2.82         1.71         1.58
PARKER & PARSLEY 86-C, LTD.                                                1.62         2.78         1.58         1.49
PARKER & PARSLEY PRIVATE INVESTMENT 86, LTD.                               1.81         2.90         1.73         1.61
PARKER & PARSLEY 87-A CONV., LTD.                                          1.75         2.86         1.68         1.54
PARKER & PARSLEY 87-A, LTD.                                                1.75         2.86         1.68         1.54
PARKER & PARSLEY 87-B CONV., LTD.                                          1.75         2.98         1.64         1.49
PARKER & PARSLEY 87-B, LTD.                                                1.75         2.98         1.64         1.49
PARKER & PARSLEY PRODUCING PROPERTIES 87-A, LTD.                           1.84         2.56         1.46         1.23
PARKER & PARSLEY PRODUCING PROPERTIES 87-B, LTD.                           1.78         2.88         1.62         1.46
PARKER & PARSLEY PRIVATE INVESTMENT 87, LTD.                               1.86         2.99         1.71         1.59
PARKER & PARSLEY 88-A CONV., L.P.                                          1.73         2.99         1.69         1.56
PARKER & PARSLEY 88-A, L.P.                                                1.73         2.99         1.69         1.56
PARKER & PARSLEY 88-B CONV., L.P.                                          1.73         2.87         1.70         1.56
PARKER & PARSLEY 88-B, L.P.                                                1.73         2.87         1.70         1.56
PARKER & PARSLEY 88-C CONV., L.P.                                          1.70         2.82         1.70         1.55
PARKER & PARSLEY 88-C, L.P.                                                1.70         2.82         1.70         1.55
PARKER & PARSLEY PRODUCING PROPERTIES 88-A, L.P.                           1.53         2.55         1.48         1.41
PARKER & PARSLEY PRIVATE INVESTMENT 88, L.P.                               1.75         2.82         1.69         1.55
PARKER & PARSLEY 89-A CONV., L.P.                                          1.91         3.07         1.81         1.74
PARKER & PARSLEY 89-A, L.P.                                                1.91         3.07         1.81         1.74
PARKER & PARSLEY 89-B CONV., L.P.                                          1.79         2.90         1.72         1.60
PARKER & PARSLEY 89-B, L.P.                                                1.79         2.90         1.72         1.60
PARKER & PARSLEY PRIVATE INVESTMENT 89, L.P.                               1.56         2.73         1.57         1.46
PARKER & PARSLEY 90-A CONV., L.P.                                          1.82         2.94         1.76         1.64
PARKER & PARSLEY 90-A, L.P.                                                1.82         2.94         1.76         1.64
PARKER & PARSLEY 90-B CONV., L.P.                                          1.68         2.84         1.62         1.50
PARKER & PARSLEY 90-B, L.P.                                                1.68         2.84         1.62         1.50
PARKER & PARSLEY 90-C CONV., L.P.                                          1.71         2.89         1.70         1.55
PARKER & PARSLEY 90-C, L.P.                                                1.71         2.89         1.70         1.55
PARKER & PARSLEY PRIVATE INVESTMENT 90, L.P.                               1.77         2.90         1.72         1.57
PARKER & PARSLEY 90 SPRABERRY PRIVATE DEV., L.P.                           1.68         2.91         1.65         1.60
PARKER & PARSLEY 91-A, L.P.                                                1.81         3.06         1.70         1.56
PARKER & PARSLEY 91-B, L.P.                                                1.73         2.93         1.61         1.47









                                                                           AVERAGE PRODUCTION COSTS (LIFTING)
                                                          --------------------------------------------------------------
                                                                             COST PER EQUIVALENT BBL(a)
                                                          --------------------------------------------------------------
                                                           FOR THE THREE MONTHS              FOR THE YEAR ENDED
                                                              ENDED MARCH 31,                    DECEMBER 31,
                                                          -----------------------   ------------------------------------
                                                              2001         2000         2000         1999        1998
                                                          -----------------------   ------------------------------------

                                                                                               
PARKER & PARSLEY 81-I, LTD.                                            $     8.77   $     9.52   $     8.39   $     8.74
PARKER & PARSLEY 81-II, LTD.                                                16.26        11.46         8.57         8.80
PARKER & PARSLEY 82-I, LTD.                                                 10.27        11.91         9.80         9.88
PARKER & PARSLEY 82-II, LTD.                                                 9.34        10.25         8.09         7.88
PARKER & PARSLEY 82-III, LTD.                                                7.80         9.20         8.06         9.00
PARKER & PARSLEY 83-A, LTD.                                                 10.68        10.52         8.64         8.76
PARKER & PARSLEY 83-B, LTD.                                                  8.42         9.12         7.60         8.27
PARKER & PARSLEY 84-A, LTD.                                                  7.95         8.64         7.70         7.66
PARKER & PARSLEY 85-A, LTD.                                                  9.78         9.66         7.02         8.70
PARKER & PARSLEY 85-B, LTD.                                                  9.21        10.19         7.70         8.48
PARKER & PARSLEY PRIVATE INVESTMENT 85-A, LTD.                               7.02         7.78         6.40         6.96
PARKER & PARSLEY SELECTED 85 PRIVATE INVESTMENT, LTD.                        8.91         9.43         8.01         7.82
PARKER & PARSLEY 86-A, LTD.                                                  8.67         8.86         7.83         9.36
PARKER & PARSLEY 86-B, LTD.                                                  8.77         8.87         7.89         7.64
PARKER & PARSLEY 86-C, LTD.                                                 10.72        10.31         8.66         7.67
PARKER & PARSLEY PRIVATE INVESTMENT 86, LTD.                                10.78        10.84         9.08         7.67
PARKER & PARSLEY 87-A CONV., LTD.                                            8.31         9.11         7.19         7.78
PARKER & PARSLEY 87-A, LTD.                                                  8.31         9.11         7.19         7.78
PARKER & PARSLEY 87-B CONV., LTD.                                            7.45         8.63         7.44         6.65
PARKER & PARSLEY 87-B, LTD.                                                  7.45         8.63         7.44         6.65
PARKER & PARSLEY PRODUCING PROPERTIES 87-A, LTD.                            10.34        12.48         8.97         9.26
PARKER & PARSLEY PRODUCING PROPERTIES 87-B, LTD.                             8.79         8.42         8.30         7.84
PARKER & PARSLEY PRIVATE INVESTMENT 87, LTD.                                 9.30         9.13         6.77         6.81
PARKER & PARSLEY 88-A CONV., L.P.                                           10.22         8.85         5.98         7.06
PARKER & PARSLEY 88-A, L.P.                                                 10.22         8.85         5.98         7.06
PARKER & PARSLEY 88-B CONV., L.P.                                            6.52         7.84         7.04         7.51
PARKER & PARSLEY 88-B, L.P.                                                  6.52         7.84         7.04         7.51
PARKER & PARSLEY 88-C CONV., L.P.                                            7.37         8.10         7.43         7.84
PARKER & PARSLEY 88-C, L.P.                                                  7.37         8.10         7.43         7.84
PARKER & PARSLEY PRODUCING PROPERTIES 88-A, L.P.                             9.70         9.69         6.31         5.87
PARKER & PARSLEY PRIVATE INVESTMENT 88, L.P.                                 8.20         7.57         6.04         6.60
PARKER & PARSLEY 89-A CONV., L.P.                                            7.97         8.23         6.75         6.92
PARKER & PARSLEY 89-A, L.P.                                                  7.97         8.23         6.75         6.92
PARKER & PARSLEY 89-B CONV., L.P.                                            8.45         8.59         7.58         7.30
PARKER & PARSLEY 89-B, L.P.                                                  8.45         8.59         7.58         7.30
PARKER & PARSLEY PRIVATE INVESTMENT 89, L.P.                                 8.91         8.99         8.69         6.80
PARKER & PARSLEY 90-A CONV., L.P.                                            7.92         9.43         7.38         6.93
PARKER & PARSLEY 90-A, L.P.                                                  7.92         9.43         7.38         6.93
PARKER & PARSLEY 90-B CONV., L.P.                                            8.57         8.68         7.28         7.31
PARKER & PARSLEY 90-B, L.P.                                                  8.57         8.68         7.28         7.31
PARKER & PARSLEY 90-C CONV., L.P.                                            9.49         8.83         7.93         8.22
PARKER & PARSLEY 90-C, L.P.                                                  9.49         8.83         7.93         8.22
PARKER & PARSLEY PRIVATE INVESTMENT 90, L.P.                                 7.39         8.22         7.01         8.24
PARKER & PARSLEY 90 SPRABERRY PRIVATE DEV., L.P.                             9.35         8.97         7.41         7.44
PARKER & PARSLEY 91-A, L.P.                                                  7.38         7.38         6.31         6.04
PARKER & PARSLEY 91-B, L.P.                                                  7.18         6.88         5.72         5.96


----------

(a)  Gas production is converted to oil equivalents at the rate of six mcf per
     barrel, representing the relative energy content of natural gas and oil.





                                      A-11
   105


                                    TABLE 11

                  PROVED RESERVES ATTRIBUTABLE TO PIONEER USA,
                NONMANAGING GENERAL PARTNERS AND LIMITED PARTNERS
                             AS OF DECEMBER 31, 2000




                                                                             TOTAL PROVED RESERVES
                                                           ----------------------------------------------------------
                                                                                                   NONMANAGING
                                                                PIONEER USA(a)                 GENERAL PARTNERS(b)
                                                           --------------------------      --------------------------
                                                             OIL &                           OIL &
                                                              NGL              GAS            NGL              GAS
                                                             (Bbls)           (Mcf)          (Bbls)           (Mcf)
                                                           ----------      ----------      ----------      ----------

                                                                                               
PARKER & PARSLEY 81-I, LTD.                                    57,816         116,841           4,224           8,535
PARKER & PARSLEY 81-II, LTD.                                   49,524          72,494           2,029           2,970
PARKER & PARSLEY 82-I, LTD.                                   114,245         257,041           4,026           9,058
PARKER & PARSLEY 82-II, LTD.                                  109,901         167,908           3,444           5,262
PARKER & PARSLEY 82-III, LTD.                                  88,780          85,126           2,916           2,796
PARKER & PARSLEY 83-A, LTD.                                   275,918         409,246          10,912          16,185
PARKER & PARSLEY 83-B, LTD.                                   340,686         554,365          13,365          21,748
PARKER & PARSLEY 84-A, LTD.                                   344,084         570,471          15,185          25,176
PARKER & PARSLEY 85-A, LTD.                                    11,187          15,154              --              --
PARKER & PARSLEY 85-B, LTD.                                     5,233           7,901              --              --
PARKER & PARSLEY PRIVATE INVESTMENT 85-A, LTD.                 11,095          12,053              --              --
PARKER & PARSLEY SELECTED 85 PRIVATE INVESTMENT, LTD.           6,238          10,351              --              --
PARKER & PARSLEY 86-A, LTD.                                     6,075          11,653              --              --
PARKER & PARSLEY 86-B, LTD.                                    16,246          21,064              --              --
PARKER & PARSLEY 86-C, LTD.                                    11,745          16,465              --              --
PARKER & PARSLEY PRIVATE INVESTMENT 86, LTD.                    3,174           4,960              --              --
PARKER & PARSLEY 87-A CONV., LTD.                               3,451           5,510              --              --
PARKER & PARSLEY 87-A, LTD.                                    21,378          34,166              --              --
PARKER & PARSLEY 87-B CONV., LTD.                               2,988           4,431              --              --
PARKER & PARSLEY 87-B, LTD.                                    12,411          18,405              --              --
PARKER & PARSLEY PRODUCING PROPERTIES 87-A, LTD.                9,632           9,615              --              --
PARKER & PARSLEY PRODUCING PROPERTIES 87-B, LTD.               13,937          22,316              --              --
PARKER & PARSLEY PRIVATE INVESTMENT 87, LTD.                    7,631           9,691              --              --
PARKER & PARSLEY 88-A CONV., L.P.                               5,253           7,315              --              --
PARKER & PARSLEY 88-A, L.P.                                    18,059          25,149              --              --
PARKER & PARSLEY 88-B CONV., L.P.                               4,220           5,515              --              --
PARKER & PARSLEY 88-B, L.P.                                    13,722          17,933              --              --
PARKER & PARSLEY 88-C CONV., L.P.                               2,870           4,039              --              --
PARKER & PARSLEY 88-C, L.P.                                     1,908           2,685              --              --
PARKER & PARSLEY PRODUCING PROPERTIES 88-A, L.P.                7,216           9,530              --              --
PARKER & PARSLEY PRIVATE INVESTMENT 88, L.P.                    7,708           9,375              --              --
PARKER & PARSLEY 89-A CONV., L.P.                               2,027           2,852              --              --
PARKER & PARSLEY 89-A, L.P.                                    13,556          19,075              --              --
PARKER & PARSLEY 89-B CONV., L.P.                               5,782           7,927              --              --
PARKER & PARSLEY 89-B, L.P.                                     9,810          13,454              --              --
PARKER & PARSLEY PRIVATE INVESTMENT 89, L.P.                    7,311           7,715              --              --
PARKER & PARSLEY 90-A CONV., L.P.                               2,145           2,701              --              --
PARKER & PARSLEY 90-A, L.P.                                    12,362          15,527              --              --
PARKER & PARSLEY 90-B CONV., L.P.                              12,549          16,252              --              --
PARKER & PARSLEY 90-B, L.P.                                    25,709          33,227              --              --
PARKER & PARSLEY 90-C CONV., L.P.                               6,507           6,522              --              --
PARKER & PARSLEY 90-C, L.P.                                     9,158           9,179              --              --
PARKER & PARSLEY PRIVATE INVESTMENT 90, L.P.                   12,668          12,480              --              --
PARKER & PARSLEY 90 SPRABERRY PRIVATE DEV., L.P.                4,177           3,814              --              --
PARKER & PARSLEY 91-A, L.P.                                    13,541          19,696              --              --
PARKER & PARSLEY 91-B, L.P.                                    11,335          13,334              --              --
                                                           ----------      ----------      ----------      ----------
                   TOTAL(D)                                 1,732,968       2,702,523          56,101          91,730
                                                           ==========      ==========      ==========      ==========







                                                                              TOTAL PROVED RESERVES
                                                            ----------------------------------------------------------

                                                                LIMITED PARTNERS(c)                  TOTAL(d)
                                                            --------------------------      --------------------------
                                                              OIL &                           OIL &
                                                               NGL              GAS            NGL              GAS
                                                              (Bbls)           (Mcf)          (Bbls)           (Mcf)
                                                            ----------      ----------      ----------      ----------

                                                                                                
PARKER & PARSLEY 81-I, LTD.                                    149,140         301,399         211,180         426,775
PARKER & PARSLEY 81-II, LTD.                                   151,342         221,535         202,895         296,999
PARKER & PARSLEY 82-I, LTD.                                    239,586         539,046         357,857         805,145
PARKER & PARSLEY 82-II, LTD.                                   294,856         450,483         408,201         623,653
PARKER & PARSLEY 82-III, LTD.                                  219,396         210,367         311,092         298,289
PARKER & PARSLEY 83-A, LTD.                                    752,434       1,116,022       1,039,264       1,541,453
PARKER & PARSLEY 83-B, LTD.                                    918,850       1,495,154       1,272,901       2,071,267
PARKER & PARSLEY 84-A, LTD.                                    990,507       1,642,204       1,349,776       2,237,851
PARKER & PARSLEY 85-A, LTD.                                    371,156         502,769         382,343         517,923
PARKER & PARSLEY 85-B, LTD.                                    299,222         451,758         304,455         459,659
PARKER & PARSLEY PRIVATE INVESTMENT 85-A, LTD.                 317,553         344,957         328,648         357,010
PARKER & PARSLEY SELECTED 85 PRIVATE INVESTMENT, LTD.          225,761         374,615         231,999         384,966
PARKER & PARSLEY 86-A, LTD.                                    446,620         856,663         452,695         868,316
PARKER & PARSLEY 86-B, LTD.                                    919,385       1,192,033         935,631       1,213,097
PARKER & PARSLEY 86-C, LTD.                                    886,520       1,242,812         898,265       1,259,277
PARKER & PARSLEY PRIVATE INVESTMENT 86, LTD.                   314,198         491,002         317,372         495,962
PARKER & PARSLEY 87-A CONV., LTD.                              178,340         284,684         181,791         290,194
PARKER & PARSLEY 87-A, LTD.                                  1,313,604       2,099,440       1,334,982       2,133,606
PARKER & PARSLEY 87-B CONV., LTD.                              245,753         364,425         248,741         368,856
PARKER & PARSLEY 87-B, LTD.                                  1,003,438       1,487,986       1,015,849       1,506,391
PARKER & PARSLEY PRODUCING PROPERTIES 87-A, LTD.               704,591         703,402         714,223         713,017
PARKER & PARSLEY PRODUCING PROPERTIES 87-B, LTD.               523,830         838,757         537,767         861,073
PARKER & PARSLEY PRIVATE INVESTMENT 87, LTD.                   755,457         959,391         763,088         969,082
PARKER & PARSLEY 88-A CONV., L.P.                              222,619         310,018         227,872         317,333
PARKER & PARSLEY 88-A, L.P.                                    758,976       1,056,963         777,035       1,082,112
PARKER & PARSLEY 88-B CONV., L.P.                              269,028         351,572         273,248         357,087
PARKER & PARSLEY 88-B, L.P.                                    659,140         861,434         672,862         879,367
PARKER & PARSLEY 88-C CONV., L.P.                              219,589         308,985         222,459         313,024
PARKER & PARSLEY 88-C, L.P.                                    156,634         220,398         158,542         223,083
PARKER & PARSLEY PRODUCING PROPERTIES 88-A, L.P.               420,265         555,001         427,481         564,531
PARKER & PARSLEY PRIVATE INVESTMENT 88, L.P.                   763,081         928,143         770,789         937,518
PARKER & PARSLEY 89-A CONV., L.P.                              200,631         282,306         202,658         285,158
PARKER & PARSLEY 89-A, L.P.                                    588,978         828,781         602,534         847,856
PARKER & PARSLEY 89-B CONV., L.P.                              434,277         595,395         440,059         603,322
PARKER & PARSLEY 89-B, L.P.                                    474,439         650,677         484,249         664,131
PARKER & PARSLEY PRIVATE INVESTMENT 89, L.P.                   461,062         486,555         468,373         494,270
PARKER & PARSLEY 90-A CONV., L.P.                              132,990         167,459         135,135         170,160
PARKER & PARSLEY 90-A, L.P.                                    381,738         479,494         394,100         495,021
PARKER & PARSLEY 90-B CONV., L.P.                              740,794         959,455         753,343         975,707
PARKER & PARSLEY 90-B, L.P.                                  2,023,300       2,615,035       2,049,009       2,648,262
PARKER & PARSLEY 90-C CONV., L.P.                              460,152         461,213         466,659         467,735
PARKER & PARSLEY 90-C, L.P.                                    741,036         742,738         750,194         751,917
PARKER & PARSLEY PRIVATE INVESTMENT 90, L.P.                   809,113         797,112         821,781         809,592
PARKER & PARSLEY 90 SPRABERRY PRIVATE DEV., L.P.               413,544         377,597         417,721         381,411
PARKER & PARSLEY 91-A, L.P.                                    965,302       1,404,059         978,843       1,423,755
PARKER & PARSLEY 91-B, L.P.                                  1,030,441       1,212,237       1,041,776       1,225,571
                                                            ----------      ----------      ----------      ----------
                   TOTAL(D)                                 25,548,668      34,823,531      27,337,737      37,617,784
                                                            ==========      ==========      ==========      ==========




----------

(a)  Represents Pioneer USA's partnership interests in each partnership as: (1)
     the sole or managing general partner of the partnership; (2) a limited
     partner of the partnership; and (3) the sole general partner of each
     nonmanaging general partner. Pioneer USA will not receive any Pioneer
     common stock or cash payment for its partnership interests in any
     participating partnership. However, as a result of the merger of each
     participating partnership, Pioneer USA will acquire 100% of the properties
     of the partnership including properties attributable to its partnership
     interests in the partnerships.

(b)  Represents four unaffiliated individuals' partnership interests as limited
     partners of each nonmanaging general partner. Excludes Pioneer USA's
     partnership interests as general partner of each nonmanaging general
     partner.

(c)  Represents the partnership interests of unaffiliated limited partners of
     each partnership. Excludes Pioneer USA's partnership interests as a limited
     partner of any partnership.

(d)  Corresponds to amounts in the reserve report prepared by Williamson
     Petroleum Consultants, Inc. as of December 31, 2000.



                                      A-12
   106


                                    TABLE 12

                  PROVED RESERVES ATTRIBUTABLE TO PIONEER USA,
                NONMANAGING GENERAL PARTNERS AND LIMITED PARTNERS
                              AS OF MARCH 31, 2001




                                                                              TOTAL PROVED RESERVES
                                                           ----------------------------------------------------------
                                                                                                  NONMANAGING
                                                                PIONEER USA(a)                 GENERAL PARTNERS(b)
                                                           --------------------------      --------------------------
                                                             OIL &                           OIL &
                                                              NGL              GAS            NGL              GAS
                                                             (Bbls)           (Mcf)          (Bbls)           (Mcf)
                                                           ----------      ----------      ----------      ----------

                                                                                               
PARKER & PARSLEY 81-I, LTD.                                    44,015          89,859           3,183           6,506
PARKER & PARSLEY 81-II, LTD.                                   34,163          51,620           1,399           2,115
PARKER & PARSLEY 82-I, LTD.                                    82,220         182,248           2,887           6,397
PARKER & PARSLEY 82-II, LTD.                                   83,829         124,152           2,621           3,875
PARKER & PARSLEY 82-III, LTD.                                  70,421          67,391           2,308           2,201
PARKER & PARSLEY 83-A, LTD.                                   214,832         320,743           8,496          12,685
PARKER & PARSLEY 83-B, LTD.                                    275,618         448,098          10,813          17,579
PARKER & PARSLEY 84-A, LTD.                                   285,567         482,485          12,603          21,293
PARKER & PARSLEY 85-A, LTD.                                     8,498          11,656              --              --
PARKER & PARSLEY 85-B, LTD.                                     3,895           5,745              --              --
PARKER & PARSLEY PRIVATE INVESTMENT 85-A, LTD.                  9,600          10,166              --              --
PARKER & PARSLEY SELECTED 85 PRIVATE INVESTMENT, LTD.           5,008           8,464              --              --
PARKER & PARSLEY 86-A, LTD.                                     4,687           8,889              --              --
PARKER & PARSLEY 86-B, LTD.                                    13,080          17,075              --              --
PARKER & PARSLEY 86-C, LTD.                                     8,652          11,999              --              --
PARKER & PARSLEY PRIVATE INVESTMENT 86, LTD.                    2,479           3,864              --              --
PARKER & PARSLEY 87-A CONV., LTD.                               2,683           4,348              --              --
PARKER & PARSLEY 87-A, LTD.                                    16,718          27,103              --              --
PARKER & PARSLEY 87-B CONV., LTD.                               2,359           3,531              --              --
PARKER & PARSLEY 87-B, LTD.                                     9,798          14,667              --              --
PARKER & PARSLEY PRODUCING PROPERTIES 87-A, LTD.                7,415           7,413              --              --
PARKER & PARSLEY PRODUCING PROPERTIES 87-B, LTD.               11,686          18,860              --              --
PARKER & PARSLEY PRIVATE INVESTMENT 87, LTD.                    6,337           8,010              --              --
PARKER & PARSLEY 88-A CONV., L.P.                               4,229           5,872              --              --
PARKER & PARSLEY 88-A, L.P.                                    14,541          20,192              --              --
PARKER & PARSLEY 88-B CONV., L.P.                               3,480           4,558              --              --
PARKER & PARSLEY 88-B, L.P.                                    11,314          14,819              --              --
PARKER & PARSLEY 88-C CONV., L.P.                               2,345           3,297              --              --
PARKER & PARSLEY 88-C, L.P.                                     1,559           2,192              --              --
PARKER & PARSLEY PRODUCING PROPERTIES 88-A, L.P.                6,055           7,923              --              --
PARKER & PARSLEY PRIVATE INVESTMENT 88, L.P.                    6,543           7,829              --              --
PARKER & PARSLEY 89-A CONV., L.P.                               1,698           2,414              --              --
PARKER & PARSLEY 89-A, L.P.                                    11,359          16,152              --              --
PARKER & PARSLEY 89-B CONV., L.P.                               4,604           6,368              --              --
PARKER & PARSLEY 89-B, L.P.                                     7,808          10,804              --              --
PARKER & PARSLEY PRIVATE INVESTMENT 89, L.P.                    5,909           6,237              --              --
PARKER & PARSLEY 90-A CONV., L.P.                               1,744           2,199              --              --
PARKER & PARSLEY 90-A, L.P.                                     9,949          12,544              --              --
PARKER & PARSLEY 90-B CONV., L.P.                              10,224          13,186              --              --
PARKER & PARSLEY 90-B, L.P.                                    20,923          26,947              --              --
PARKER & PARSLEY 90-C CONV., L.P.                               5,218           5,187              --              --
PARKER & PARSLEY 90-C, L.P.                                     7,344           7,301              --              --
PARKER & PARSLEY PRIVATE INVESTMENT 90, L.P.                   10,449          10,006              --              --
PARKER & PARSLEY 90 SPRABERRY PRIVATE DEV., L.P.                3,482           3,172              --              --
PARKER & PARSLEY 91-A, L.P.                                    11,647          16,716              --              --
PARKER & PARSLEY 91-B, L.P.                                     9,825          11,641              --              --
                                                           ----------      ----------      ----------      ----------
                   TOTAL                                    1,375,809       2,145,942          44,310          72,651
                                                           ==========      ==========      ==========      ==========








                                                                               TOTAL PROVED RESERVES
                                                             ----------------------------------------------------------

                                                                 LIMITED PARTNERS(c)                    TOTAL
                                                             --------------------------      --------------------------
                                                               OIL &                           OIL &
                                                                NGL              GAS            NGL               GAS
                                                               (Bbls)           (Mcf)          (Bbls)           (Mcf)
                                                             ----------      ----------      ----------      ----------

                                                                                                 
PARKER & PARSLEY 81-I, LTD.                                     119,464         242,599         166,662         338,964
PARKER & PARSLEY 81-II, LTD.                                    106,202         158,535         141,764         212,270
PARKER & PARSLEY 82-I, LTD.                                     174,292         386,652         259,399         575,297
PARKER & PARSLEY 82-II, LTD.                                    229,733         344,629         316,183         472,656
PARKER & PARSLEY 82-III, LTD.                                   176,244         171,833         248,973         241,425
PARKER & PARSLEY 83-A, LTD.                                     585,852         874,674         809,180       1,208,102
PARKER & PARSLEY 83-B, LTD.                                     743,358       1,208,548       1,029,789       1,674,225
PARKER & PARSLEY 84-A, LTD.                                     822,057       1,388,920       1,120,227       1,892,698
PARKER & PARSLEY 85-A, LTD.                                     281,965         386,713         290,463         398,369
PARKER & PARSLEY 85-B, LTD.                                     222,731         328,479         226,626         334,224
PARKER & PARSLEY PRIVATE INVESTMENT 85-A, LTD.                  274,765         290,970         284,365         301,136
PARKER & PARSLEY SELECTED 85 PRIVATE INVESTMENT, LTD.           181,256         306,332         186,264         314,796
PARKER & PARSLEY 86-A, LTD.                                     344,581         653,460         349,268         662,349
PARKER & PARSLEY 86-B, LTD.                                     740,201         966,261         753,281         983,336
PARKER & PARSLEY 86-C, LTD.                                     653,081         905,703         661,733         917,702
PARKER & PARSLEY PRIVATE INVESTMENT 86, LTD.                    245,444         382,576         247,923         386,440
PARKER & PARSLEY 87-A CONV., LTD.                               138,639         224,665         141,322         229,013
PARKER & PARSLEY 87-A, LTD.                                   1,027,295       1,665,437       1,044,013       1,692,540
PARKER & PARSLEY 87-B CONV., LTD.                               193,991         290,404         196,350         293,935
PARKER & PARSLEY 87-B, LTD.                                     792,129       1,185,806         801,927       1,200,473
PARKER & PARSLEY PRODUCING PROPERTIES 87-A, LTD.                542,443         542,313         549,858         549,726
PARKER & PARSLEY PRODUCING PROPERTIES 87-B, LTD.                439,208         708,847         450,894         727,707
PARKER & PARSLEY PRIVATE INVESTMENT 87, LTD.                    627,335         792,961         633,672         800,971
PARKER & PARSLEY 88-A CONV., L.P.                               179,233         248,890         183,462         254,762
PARKER & PARSLEY 88-A, L.P.                                     611,107         848,608         625,648         868,800
PARKER & PARSLEY 88-B CONV., L.P.                               221,815         290,537         225,295         295,095
PARKER & PARSLEY 88-B, L.P.                                     543,481         711,836         554,795         726,655
PARKER & PARSLEY 88-C CONV., L.P.                               179,408         252,233         181,753         255,530
PARKER & PARSLEY 88-C, L.P.                                     127,978         179,932         129,537         182,124
PARKER & PARSLEY PRODUCING PROPERTIES 88-A, L.P.                352,641         461,401         358,696         469,324
PARKER & PARSLEY PRIVATE INVESTMENT 88, L.P.                    647,747         775,098         654,290         782,927
PARKER & PARSLEY 89-A CONV., L.P.                               168,085         239,019         169,783         241,433
PARKER & PARSLEY 89-A, L.P.                                     493,498         701,759         504,857         717,911
PARKER & PARSLEY 89-B CONV., L.P.                               345,765         478,251         350,369         484,619
PARKER & PARSLEY 89-B, L.P.                                     377,628         522,545         385,436         533,349
PARKER & PARSLEY PRIVATE INVESTMENT 89, L.P.                    372,674         393,332         378,583         399,569
PARKER & PARSLEY 90-A CONV., L.P.                               108,108         136,309         109,852         138,508
PARKER & PARSLEY 90-A, L.P.                                     307,219         387,363         317,168         399,907
PARKER & PARSLEY 90-B CONV., L.P.                               603,559         778,404         613,783         791,590
PARKER & PARSLEY 90-B, L.P.                                   1,646,642       2,120,743       1,667,565       2,147,690
PARKER & PARSLEY 90-C CONV., L.P.                               369,034         366,832         374,252         372,019
PARKER & PARSLEY 90-C, L.P.                                     594,276         590,739         601,620         598,040
PARKER & PARSLEY PRIVATE INVESTMENT 90, L.P.                    667,438         639,137         677,887         649,143
PARKER & PARSLEY 90 SPRABERRY PRIVATE DEV., L.P.                344,669         314,060         348,151         317,232
PARKER & PARSLEY 91-A, L.P.                                     830,236       1,191,626         841,883       1,208,342
PARKER & PARSLEY 91-B, L.P.                                     893,203       1,058,325         903,028       1,069,966
                                                             ----------      ----------      ----------      ----------
                   TOTAL                                     20,647,710      28,094,296      22,067,829      30,312,889
                                                             ==========      ==========      ==========      ==========





----------

(a)  Represents Pioneer USA's partnership interests in each partnership as: (1)
     the sole or managing general partner of the partnership; (2) a limited
     partner of the partnership; and (3) the sole general partner of each
     nonmanaging general partner. Pioneer USA will not receive any Pioneer
     common stock or cash payment for its partnership interests in any
     participating partnership. However, as a result of the merger of each
     participating partnership, Pioneer USA will acquire 100% of the properties
     of the partnership including properties attributable to its partnership
     interests in the partnerships.

(b)  Represents four unaffiliated individuals' partnership interests as limited
     partners of each nonmanaging general partner. Excludes Pioneer USA's
     partnership interests as general partner of each nonmanaging general
     partner.

(c)  Represents the partnership interests of unaffiliated limited partners of
     each partnership. Excludes Pioneer USA's partnership interests as a limited
     partner of any partnership.



                                      A-13
   107


                                    TABLE 13

                   OIL, NATURAL GAS LIQUIDS AND GAS PRODUCTION
             FOR THE THREE MONTHS ENDED MARCH 31, 2001 AND 2000 AND
                THE YEARS ENDED DECEMBER 31, 2000, 1999 AND 1998




                                                                                    OIL & NGL (Bbls)
                                                        ------------------------------------------------------------------------
                                                           FOR THE THREE MONTHS                  FOR THE YEAR ENDED
                                                              ENDED MARCH 31,                         DECEMBER 31,
                                                        ---------------------------   ------------------------------------------
                                                            2001           2000           2000           1999           1998
                                                        ------------   ------------   ------------   ------------   ------------

                                                                                                     
PARKER & PARSLEY 81-I, LTD.                                                   3,619         13,976         14,970         13,937
PARKER & PARSLEY 81-II, LTD.                                                  2,737         13,921         13,232         16,033
PARKER & PARSLEY 82-I, LTD.                                                   6,243         24,158         23,886         25,898
PARKER & PARSLEY 82-II, LTD.                                                  6,483         24,922         27,554         27,854
PARKER & PARSLEY 82-III, LTD.                                                 5,615         20,646         20,801         19,540
PARKER & PARSLEY 83-A, LTD.                                                  16,424         66,679         69,238         67,612
PARKER & PARSLEY 83-B, LTD.                                                  21,782         81,814         89,446         93,695
PARKER & PARSLEY 84-A, LTD.                                                  21,791         85,485         85,868         88,702
PARKER & PARSLEY 85-A, LTD.                                                   7,435         27,458         31,246         27,808
PARKER & PARSLEY 85-B, LTD.                                                   4,993         20,809         21,410         24,803
PARKER & PARSLEY PRIVATE INVESTMENT 85-A, LTD.                                4,692         17,619         20,664         21,200
PARKER & PARSLEY SELECTED 85 PRIVATE INVESTMENT, LTD.                         3,625         15,698         14,598         15,439
PARKER & PARSLEY 86-A, LTD.                                                   7,966         31,785         33,226         31,472
PARKER & PARSLEY 86-B, LTD.                                                  15,880         62,337         63,132         70,399
PARKER & PARSLEY 86-C, LTD.                                                  16,610         66,329         64,894         74,674
PARKER & PARSLEY PRIVATE INVESTMENT 86, LTD.                                  5,424         20,938         20,843         22,245
PARKER & PARSLEY 87-A CONV., LTD.                                             3,368         13,096         13,578         14,371
PARKER & PARSLEY 87-A, LTD.                                                  25,185         97,824        101,441        107,375
PARKER & PARSLEY 87-B CONV., LTD.                                             4,280         16,015         16,758         17,879
PARKER & PARSLEY 87-B, LTD.                                                  17,478         65,401         68,433         73,036
PARKER & PARSLEY PRODUCING PROPERTIES 87-A, LTD.                             13,873         53,656         53,101         64,367
PARKER & PARSLEY PRODUCING PROPERTIES 87-B, LTD.                             10,018         33,115         35,770         40,796
PARKER & PARSLEY PRIVATE INVESTMENT 87, LTD.                                  9,329         35,242         40,495         42,801
PARKER & PARSLEY 88-A CONV., L.P.                                             3,496         14,604         17,052         16,899
PARKER & PARSLEY 88-A, L.P.                                                  11,946         49,808         58,141         57,635
PARKER & PARSLEY 88-B CONV., L.P.                                             4,667         18,572         16,986         17,610
PARKER & PARSLEY 88-B, L.P.                                                  11,503         45,729         41,830         43,365
PARKER & PARSLEY 88-C CONV., L.P.                                             3,815         15,453         14,136         14,859
PARKER & PARSLEY 88-C, L.P.                                                   2,729         11,023         10,071         10,596
PARKER & PARSLEY PRODUCING PROPERTIES 88-A, L.P.                              6,060         26,976         30,280         34,491
PARKER & PARSLEY PRIVATE INVESTMENT 88, L.P.                                 10,892         46,284         48,802         48,933
PARKER & PARSLEY 89-A CONV., L.P.                                             3,150         13,092         14,166         14,102
PARKER & PARSLEY 89-A, L.P.                                                   9,366         38,923         42,129         41,931
PARKER & PARSLEY 89-B CONV., L.P.                                             7,859         30,959         32,585         35,481
PARKER & PARSLEY 89-B, L.P.                                                   8,656         34,089         35,879         39,063
PARKER & PARSLEY PRIVATE INVESTMENT 89, L.P.                                  7,721         30,738         30,310         36,741
PARKER & PARSLEY 90-A CONV., L.P.                                             2,527          9,876         10,130         11,399
PARKER & PARSLEY 90-A, L.P.                                                   7,290         28,519         29,248         32,915
PARKER & PARSLEY 90-B CONV., L.P.                                            12,969         53,388         53,864         58,543
PARKER & PARSLEY 90-B, L.P.                                                  35,197        144,804        146,064        158,775
PARKER & PARSLEY 90-C CONV., L.P.                                             7,745         32,773         32,618         33,187
PARKER & PARSLEY 90-C, L.P.                                                  12,449         52,686         52,433         53,358
PARKER & PARSLEY PRIVATE INVESTMENT 90, L.P.                                 13,108         52,913         46,335         49,468
PARKER & PARSLEY 90 SPRABERRY PRIVATE DEV., L.P.                              5,652         22,593         20,688         20,835
PARKER & PARSLEY 91-A, L.P.                                                  16,199         64,129         64,820         70,623
PARKER & PARSLEY 91-B, L.P.                                                  17,038         69,550         65,056         66,527
                                                                       ------------   ------------   ------------   ------------
                      TOTAL                                                 456,884      1,816,404      1,858,207      1,969,272
                                                                       ============   ============   ============   ============




                                                                                         GAS (Mcf)
                                                        ------------------------------------------------------------------------
                                                            FOR THE THREE MONTHS                  FOR THE YEAR ENDED
                                                              ENDED MARCH 31,                         DECEMBER 31,
                                                        ---------------------------   ------------------------------------------
                                                            2001           2000           2000           1999           1998
                                                        ------------   ------------   ------------   ------------   ------------

                                                                                                     
PARKER & PARSLEY 81-I, LTD.                                                   6,102         25,901         28,708         24,638
PARKER & PARSLEY 81-II, LTD.                                                  1,489         15,864         19,167         22,439
PARKER & PARSLEY 82-I, LTD.                                                  12,235         45,981         48,380         48,971
PARKER & PARSLEY 82-II, LTD.                                                  9,151         35,900         42,858         41,862
PARKER & PARSLEY 82-III, LTD.                                                 6,304         21,480         23,061         17,680
PARKER & PARSLEY 83-A, LTD.                                                  22,988         94,612        109,716         95,156
PARKER & PARSLEY 83-B, LTD.                                                  35,379        132,106        157,842        147,495
PARKER & PARSLEY 84-A, LTD.                                                  35,071        138,617        154,235        145,870
PARKER & PARSLEY 85-A, LTD.                                                  11,812         41,549         55,226         43,021
PARKER & PARSLEY 85-B, LTD.                                                   7,429         30,909         33,467         41,501
PARKER & PARSLEY PRIVATE INVESTMENT 85-A, LTD.                                5,061         20,905         23,218         22,343
PARKER & PARSLEY SELECTED 85 PRIVATE INVESTMENT, LTD.                         5,393         22,987         27,627         25,328
PARKER & PARSLEY 86-A, LTD.                                                  14,461         56,549         62,354         49,805
PARKER & PARSLEY 86-B, LTD.                                                  20,435         79,859         86,726         97,715
PARKER & PARSLEY 86-C, LTD.                                                  21,750         95,610        105,081        129,149
PARKER & PARSLEY PRIVATE INVESTMENT 86, LTD.                                  7,936         33,570         30,923         33,219
PARKER & PARSLEY 87-A CONV., LTD.                                             5,425         20,355         24,503         24,025
PARKER & PARSLEY 87-A, LTD.                                                  40,626        152,075        183,099        179,494
PARKER & PARSLEY 87-B CONV., LTD.                                             6,437         23,682         24,436         25,477
PARKER & PARSLEY 87-B, LTD.                                                  26,331         96,740         99,771        104,072
PARKER & PARSLEY PRODUCING PROPERTIES 87-A, LTD.                              9,135         45,872         53,145         56,240
PARKER & PARSLEY PRODUCING PROPERTIES 87-B, LTD.                             14,555         49,380         48,774         50,220
PARKER & PARSLEY PRIVATE INVESTMENT 87, LTD.                                 11,546         48,307         52,874         58,036
PARKER & PARSLEY 88-A CONV., L.P.                                             4,685         21,399         27,417         25,367
PARKER & PARSLEY 88-A, L.P.                                                  15,987         72,965         93,498         86,501
PARKER & PARSLEY 88-B CONV., L.P.                                             5,699         21,781         23,221         21,214
PARKER & PARSLEY 88-B, L.P.                                                  14,019         53,620         57,190         52,254
PARKER & PARSLEY 88-C CONV., L.P.                                             4,769         19,618         21,119         19,764
PARKER & PARSLEY 88-C, L.P.                                                   3,392         13,979         15,049         14,091
PARKER & PARSLEY PRODUCING PROPERTIES 88-A, L.P.                              9,789         37,939         44,467         51,099
PARKER & PARSLEY PRIVATE INVESTMENT 88, L.P.                                 15,649         59,532         66,701         61,718
PARKER & PARSLEY 89-A CONV., L.P.                                             4,757         20,057         20,484         21,106
PARKER & PARSLEY 89-A, L.P.                                                  14,142         59,638         60,905         62,751
PARKER & PARSLEY 89-B CONV., L.P.                                            11,218         42,179         46,681         52,345
PARKER & PARSLEY 89-B, L.P.                                                  12,352         46,454         51,400         57,643
PARKER & PARSLEY PRIVATE INVESTMENT 89, L.P.                                  6,473         30,037         32,985         44,624
PARKER & PARSLEY 90-A CONV., L.P.                                             3,430         13,365         14,989         16,309
PARKER & PARSLEY 90-A, L.P.                                                   9,897         38,570         43,302         47,086
PARKER & PARSLEY 90-B CONV., L.P.                                            15,621         64,786         70,803         73,460
PARKER & PARSLEY 90-B, L.P.                                                  42,382        175,696        192,016        199,215
PARKER & PARSLEY 90-C CONV., L.P.                                             6,434         30,423         29,399         30,348
PARKER & PARSLEY 90-C, L.P.                                                  10,341         48,907         47,265         48,787
PARKER & PARSLEY PRIVATE INVESTMENT 90, L.P.                                 12,754         49,484         47,331         54,218
PARKER & PARSLEY 90 SPRABERRY PRIVATE DEV., L.P.                              3,949         22,121         19,579         24,095
PARKER & PARSLEY 91-A, L.P.                                                  22,979         94,315        100,615        108,617
PARKER & PARSLEY 91-B, L.P.                                                  19,802         85,556         74,025         68,244
                                                                       ------------   ------------   ------------   ------------
                      TOTAL                                                 607,571      2,451,231      2,695,632      2,724,612
                                                                       ============   ============   ============   ============






                                                                                     TOTAL (BOE)(a)
                                                        ------------------------------------------------------------------------
                                                           FOR THE THREE MONTHS                  FOR THE YEAR ENDED
                                                               ENDED MARCH 31,                       DECEMBER 31,
                                                        ---------------------------   ------------------------------------------
                                                            2001           2000           2000           1999           1998
                                                        ------------   ------------   ------------   ------------   ------------

                                                                                                     
PARKER & PARSLEY 81-I, LTD.                                                   4,636         18,293         19,755         18,043
PARKER & PARSLEY 81-II, LTD.                                                  2,985         16,565         16,427         19,773
PARKER & PARSLEY 82-I, LTD.                                                   8,282         31,822         31,949         34,060
PARKER & PARSLEY 82-II, LTD.                                                  8,008         30,905         34,697         34,831
PARKER & PARSLEY 82-III, LTD.                                                 6,666         24,226         24,645         22,487
PARKER & PARSLEY 83-A, LTD.                                                  20,255         82,448         87,524         83,471
PARKER & PARSLEY 83-B, LTD.                                                  27,679        103,832        115,753        118,278
PARKER & PARSLEY 84-A, LTD.                                                  27,636        108,588        111,574        113,014
PARKER & PARSLEY 85-A, LTD.                                                   9,404         34,383         40,450         34,978
PARKER & PARSLEY 85-B, LTD.                                                   6,231         25,961         26,988         31,720
PARKER & PARSLEY PRIVATE INVESTMENT 85-A, LTD.                                5,536         21,103         24,534         24,924
PARKER & PARSLEY SELECTED 85 PRIVATE INVESTMENT, LTD.                         4,524         19,529         19,203         19,660
PARKER & PARSLEY 86-A, LTD.                                                  10,376         41,210         43,618         39,773
PARKER & PARSLEY 86-B, LTD.                                                  19,286         75,647         77,586         86,685
PARKER & PARSLEY 86-C, LTD.                                                  20,235         82,264         82,408         96,199
PARKER & PARSLEY PRIVATE INVESTMENT 86, LTD.                                  6,747         26,533         25,997         27,782
PARKER & PARSLEY 87-A CONV., LTD.                                             4,272         16,489         17,662         18,375
PARKER & PARSLEY 87-A, LTD.                                                  31,956        123,170        131,958        137,291
PARKER & PARSLEY 87-B CONV., LTD.                                             5,353         19,962         20,831         22,125
PARKER & PARSLEY 87-B, LTD.                                                  21,867         81,524         85,062         90,381
PARKER & PARSLEY PRODUCING PROPERTIES 87-A, LTD.                             15,396         61,301         61,959         73,740
PARKER & PARSLEY PRODUCING PROPERTIES 87-B, LTD.                             12,444         41,345         43,899         49,166
PARKER & PARSLEY PRIVATE INVESTMENT 87, LTD.                                 11,253         43,293         49,307         52,474
PARKER & PARSLEY 88-A CONV., L.P.                                             4,277         18,171         21,622         21,127
PARKER & PARSLEY 88-A, L.P.                                                  14,611         61,969         73,724         72,052
PARKER & PARSLEY 88-B CONV., L.P.                                             5,617         22,202         20,856         21,146
PARKER & PARSLEY 88-B, L.P.                                                  13,840         54,666         51,362         52,074
PARKER & PARSLEY 88-C CONV., L.P.                                             4,610         18,723         17,656         18,153
PARKER & PARSLEY 88-C, L.P.                                                   3,294         13,353         12,579         12,945
PARKER & PARSLEY PRODUCING PROPERTIES 88-A, L.P.                              7,692         33,299         37,691         43,008
PARKER & PARSLEY PRIVATE INVESTMENT 88, L.P.                                 13,500         56,206         59,919         59,219
PARKER & PARSLEY 89-A CONV., L.P.                                             3,943         16,435         17,580         17,620
PARKER & PARSLEY 89-A, L.P.                                                  11,723         48,863         52,280         52,390
PARKER & PARSLEY 89-B CONV., L.P.                                             9,729         37,989         40,365         44,205
PARKER & PARSLEY 89-B, L.P.                                                  10,715         41,831         44,446         48,670
PARKER & PARSLEY PRIVATE INVESTMENT 89, L.P.                                  8,800         35,744         35,808         44,178
PARKER & PARSLEY 90-A CONV., L.P.                                             3,099         12,104         12,628         14,117
PARKER & PARSLEY 90-A, L.P.                                                   8,940         34,947         36,465         40,763
PARKER & PARSLEY 90-B CONV., L.P.                                            15,573         64,186         65,665         70,786
PARKER & PARSLEY 90-B, L.P.                                                  42,261        174,087        178,067        191,978
PARKER & PARSLEY 90-C CONV., L.P.                                             8,817         37,844         37,518         38,245
PARKER & PARSLEY 90-C, L.P.                                                  14,173         60,837         60,311         61,489
PARKER & PARSLEY PRIVATE INVESTMENT 90, L.P.                                 15,234         61,160         54,224         58,504
PARKER & PARSLEY 90 SPRABERRY PRIVATE DEV., L.P.                              6,310         26,280         23,951         24,851
PARKER & PARSLEY 91-A, L.P.                                                  20,029         79,848         81,589         88,726
PARKER & PARSLEY 91-B, L.P.                                                  20,338         83,809         77,394         77,901
                                                                       ------------   ------------   ------------   ------------
                      TOTAL                                                 558,152      2,224,946      2,307,486      2,423,377
                                                                       ============   ============   ============   ============











----------

(a)  Gas production is converted to oil equivalents at the rate of six mcf per
     barrel, representing the relative energy content of natural gas and oil.




                                      A-14
   108


                                    TABLE 14

                     PRODUCTIVE WELLS AND DEVELOPED ACREAGE
                             AS OF DECEMBER 31, 2000



                                                             PRODUCTIVE OIL AND
                                                                  GAS WELLS                  DEVELOPED ACRES
                                                           ------------------------      ------------------------
                                                            GROSS(A)        NET(B)        GROSS(A)       NET(B)
                                                           ---------      ---------      ---------      ---------

                                                                                            
PARKER & PARSLEY 81-I, LTD.                                       16           9.13          2,328          1,250
PARKER & PARSLEY 81-II, LTD.                                      12           8.40          1,563          1,050
PARKER & PARSLEY 82-I, LTD.                                       17          16.19          1,702          1,557
PARKER & PARSLEY 82-II, LTD.                                      16          15.38          1,882          1,489
PARKER & PARSLEY 82-III, LTD.                                     13          11.63          2,013          1,381
PARKER & PARSLEY 83-A, LTD.                                       42          36.59          5,154          3,602
PARKER & PARSLEY 83-B, LTD.                                       41          40.66          5,227          4,190
PARKER & PARSLEY 84-A, LTD.                                       38          37.55          4,929          4,019
PARKER & PARSLEY 85-A, LTD.                                       21          17.05          2,083          1,315
PARKER & PARSLEY 85-B, LTD.                                       17          13.05          2,536          1,215
PARKER & PARSLEY PRIVATE INVESTMENT 85-A, LTD.                    11           7.78          1,204            658
PARKER & PARSLEY SELECTED 85 PRIVATE INVESTMENT, LTD.             12           9.23          1,282            738
PARKER & PARSLEY 86-A, LTD.                                       26          21.86          1,689          1,108
PARKER & PARSLEY 86-B, LTD.                                       43          35.65          2,709          1,694
PARKER & PARSLEY 86-C, LTD.                                       53          44.36          4,432          2,786
PARKER & PARSLEY PRIVATE INVESTMENT 86, LTD.                      14          12.37          1,685          1,131
PARKER & PARSLEY 87-A CONV., LTD.                                 73           7.06          6,498            659
PARKER & PARSLEY 87-A, LTD.                                       73          52.76          6,498          4,926
PARKER & PARSLEY 87-B CONV., LTD.                                 49           8.31          4,465            796
PARKER & PARSLEY 87-B, LTD.                                       49          33.94          4,465          3,251
PARKER & PARSLEY PRODUCING PROPERTIES 87-A, LTD.                  85          40.35         10,576          3,615
PARKER & PARSLEY PRODUCING PROPERTIES 87-B, LTD.                  34          20.52          4,302          1,609
PARKER & PARSLEY PRIVATE INVESTMENT 87, LTD.                      24          19.65          1,685          1,130
PARKER & PARSLEY 88-A CONV., L.P.                                 39           8.01          3,286            592
PARKER & PARSLEY 88-A, L.P.                                       39          25.98          3,286          1,628
PARKER & PARSLEY 88-B CONV., L.P.                                 41           7.65          2,766            956
PARKER & PARSLEY 88-B, L.P.                                       41          18.82          2,766            412
PARKER & PARSLEY 88-C CONV., L.P.                                 41           6.97          2,757            343
PARKER & PARSLEY 88-C, L.P.                                       41           4.97          2,757            244
PARKER & PARSLEY PRODUCING PROPERTIES 88-A, L.P.                  23          18.69          1,689          1,193
PARKER & PARSLEY PRIVATE INVESTMENT 88, L.P.                      22          19.18          1,873          1,211
PARKER & PARSLEY 89-A CONV., L.P.                                 32           5.87          2,811            553
PARKER & PARSLEY 89-A, L.P.                                       32          17.45          2,811          1,645
PARKER & PARSLEY 89-B CONV., L.P.                                 33          13.72          2,992          1,150
PARKER & PARSLEY 89-B, L.P.                                       33          15.12          2,992          1,267
PARKER & PARSLEY PRIVATE INVESTMENT 89, L.P.                      19          13.87          1,913          1,253
PARKER & PARSLEY 90-A CONV., L.P.                                 25           4.56          2,045            395
PARKER & PARSLEY 90-A, L.P.                                       25          13.17          2,045          1,141
PARKER & PARSLEY 90-B CONV., L.P.                                103          23.18          9,729          2,086
PARKER & PARSLEY 90-B, L.P.                                      103          62.92          9,729          5,658
PARKER & PARSLEY 90-C CONV., L.P.                                 42          13.68          1,021            316
PARKER & PARSLEY 90-C, L.P.                                       42          21.99          1,021            509
PARKER & PARSLEY PRIVATE INVESTMENT 90, L.P.                      27          20.65          2,333          1,556
PARKER & PARSLEY 90 SPRABERRY PRIVATE DEV., L.P.                  12           9.00          1,017            658
PARKER & PARSLEY 91-A, L.P.                                       47          24.71          4,389          1,891
PARKER & PARSLEY 91-B, L.P.                                       29          21.97          1,922          1,301
                                                           ---------      ---------      ---------      ---------
                      TOTAL                                    1,670         911.60        150,857         73,127
                                                           =========      =========      =========      =========


----------

(a)  A "gross well" or "gross acre" is a well or an acre in which a working
     interest is owned. The number of gross wells or acres represents the sum of
     the wells or acres in which a working interest is owned.

(b)  A "net well" or "net acre" is deemed to exist when the sum of the
     fractional working interests in gross wells or acres equals one. The number
     of net wells or acres is the sum of the fractional working interests in
     gross wells or acres.




                                      A-15
   109


                                    TABLE 15

                   RECENT TRADES OF PARTNERSHIP INTERESTS (A)
                              PER $1,000 INVESTMENT
          FOR THE THREE MONTHS ENDED MARCH 31, 2001 AND THE YEARS ENDED
                           DECEMBER 31, 2000 AND 1999



                                                                    PER $1,000 INVESTMENT
                                                      ------------------------------------------------------
                                                            FOR THE THREE MONTHS ENDED MARCH 31, 2001
                                                      ------------------------------------------------------
                                                           SALES PRICE
                                                      ------------------------       NUMBER         NUMBER
                                                        HIGH            LOW         OF SALES         SOLD
                                                      ---------      ---------      ---------      ---------
                                                                                       
PARKER & PARSLEY 82-I, LTD.
PARKER & PARSLEY 82-II, LTD.
PARKER & PARSLEY 83-A, LTD.
PARKER & PARSLEY 83-B, LTD.
PARKER & PARSLEY 84-A, LTD.
PARKER & PARSLEY 85-A, LTD.
PARKER & PARSLEY 85-B, LTD.
PARKER & PARSLEY 86-A, LTD.
PARKER & PARSLEY 86-B, LTD.
PARKER & PARSLEY 86-C, LTD.
PARKER & PARSLEY 87-A, LTD.
PARKER & PARSLEY 87-B, LTD.
PARKER & PARSLEY PRODUCING PROPERTIES 87-A, LTD.
PARKER & PARSLEY PRODUCING PROPERTIES 87-B, LTD.
PARKER & PARSLEY 88-A, L.P.
PARKER & PARSLEY 88-B, L.P.
PARKER & PARSLEY 88-C, L.P.
PARKER & PARSLEY PRODUCING PROPERTIES 88-A, L.P.
PARKER & PARSLEY 89-A, L.P.
PARKER & PARSLEY 89-B, L.P.
PARKER & PARSLEY 90-A, L.P.
PARKER & PARSLEY 90-B, L.P.
PARKER & PARSLEY 90-C, L.P.
PARKER & PARSLEY 91-A, L.P.
PARKER & PARSLEY 91-B, L.P.







                                                                       PER $1,000 INVESTMENT
                                                      ------------------------------------------------------
                                                                FOR THE YEAR ENDED DECEMBER 31, 2000
                                                      ------------------------------------------------------
                                                           SALES PRICE
                                                      ------------------------       NUMBER         NUMBER
                                                        HIGH            LOW         OF SALES         SOLD
                                                      ---------      ---------      ---------      ---------
                                                                                       
PARKER & PARSLEY 82-I, LTD.                           $   47.75      $   37.50              5             61
PARKER & PARSLEY 82-II, LTD.                              89.00          45.00              6             60
PARKER & PARSLEY 83-A, LTD.                              112.50          94.00              6             60
PARKER & PARSLEY 83-B, LTD.                              135.00          96.11              5            105
PARKER & PARSLEY 84-A, LTD.                              165.00         101.11              8            175
PARKER & PARSLEY 85-A, LTD.                                  --             --             --             --
PARKER & PARSLEY 85-B, LTD.                              135.00         100.00              4             35
PARKER & PARSLEY 86-A, LTD.                              160.00          65.00              4             45
PARKER & PARSLEY 86-B, LTD.                              160.00          97.00              8            120
PARKER & PARSLEY 86-C, LTD.                              135.00          95.45              4             40
PARKER & PARSLEY 87-A, LTD.                              163.75          78.00             12            128
PARKER & PARSLEY 87-B, LTD.                              179.25         105.66             14            255
PARKER & PARSLEY PRODUCING PROPERTIES 87-A, LTD.         280.00         184.00              2             12
PARKER & PARSLEY PRODUCING PROPERTIES 87-B, LTD.         310.00         146.00              3             47
PARKER & PARSLEY 88-A, L.P.                              205.00         135.00              6             43
PARKER & PARSLEY 88-B, L.P.                              188.12         128.00              3            230
PARKER & PARSLEY 88-C, L.P.                              175.00         138.20              4             17
PARKER & PARSLEY PRODUCING PROPERTIES 88-A, L.P.             --             --             --             --
PARKER & PARSLEY 89-A, L.P.                              221.00         140.00              7            100
PARKER & PARSLEY 89-B, L.P.                              215.00         215.00              1              5
PARKER & PARSLEY 90-A, L.P.                              230.00         126.11              3             35
PARKER & PARSLEY 90-B, L.P.                              211.12         100.00             19            275
PARKER & PARSLEY 90-C, L.P.                              210.00         112.30             12            251
PARKER & PARSLEY 91-A, L.P.                              259.00         212.00              2             22
PARKER & PARSLEY 91-B, L.P.                              235.11         235.11              1             10







                                                                      PER $1,000 INVESTMENT
                                                     ------------------------------------------------------
                                                              FOR THE YEAR ENDED DECEMBER 31, 1999
                                                     ------------------------------------------------------
                                                          SALES PRICE
                                                     ------------------------       NUMBER          NUMBER
                                                       HIGH            LOW         OF SALES          SOLD
                                                     ---------      ---------      ---------      ---------
                                                                                       
PARKER & PARSLEY 82-I, LTD.                          $   15.00      $    4.17              2             24
PARKER & PARSLEY 82-II, LTD.                             30.83          10.50              3             41
PARKER & PARSLEY 83-A, LTD.                              54.00          36.75             10            151
PARKER & PARSLEY 83-B, LTD.                              63.11          43.00              2             35
PARKER & PARSLEY 84-A, LTD.                              72.00          44.00              8            104
PARKER & PARSLEY 85-A, LTD.                              61.00          10.00              5             50
PARKER & PARSLEY 85-B, LTD.                              75.00          75.00              2             30
PARKER & PARSLEY 86-A, LTD.                              55.00          10.00              2             40
PARKER & PARSLEY 86-B, LTD.                             111.00          62.34              9            108
PARKER & PARSLEY 86-C, LTD.                              80.00          45.00              5             32
PARKER & PARSLEY 87-A, LTD.                             112.00          65.00             10            155
PARKER & PARSLEY 87-B, LTD.                             101.67          10.00             12            205
PARKER & PARSLEY PRODUCING PROPERTIES 87-A, LTD.        175.00         112.00              4             79
PARKER & PARSLEY PRODUCING PROPERTIES 87-B, LTD.        170.00         128.00              3             30
PARKER & PARSLEY 88-A, L.P.                             105.11          57.00              3             25
PARKER & PARSLEY 88-B, L.P.                             111.00          62.00              4             50
PARKER & PARSLEY 88-C, L.P.                              56.00          56.00              1             25
PARKER & PARSLEY PRODUCING PROPERTIES 88-A, L.P.        225.00         225.00              1              4
PARKER & PARSLEY 89-A, L.P.                             138.00          86.00              5             70
PARKER & PARSLEY 89-B, L.P.                             146.11         105.00              5             85
PARKER & PARSLEY 90-A, L.P.                              92.00          84.33              2             25
PARKER & PARSLEY 90-B, L.P.                             175.00          90.00             12            115
PARKER & PARSLEY 90-C, L.P.                             136.33          60.51              8            125
PARKER & PARSLEY 91-A, L.P.                             121.00          88.00              2             13
PARKER & PARSLEY 91-B, L.P.                             135.00         135.00              1             10








---------------

(a)  This table contains historical information about recent trades of
     partnership interests on a per $1,000 investment as determined from "The
     Partnership Spectrum." The price information represents the prices reported
     to have been paid to the sellers net of commissions paid by buyers. This
     information should not be relied upon as any indication of the price at
     which the partnership interests may trade. There may have been other
     secondary sale transactions in the partnership interests, although no
     information regarding any such transactions is available to Pioneer USA.
     Because the information regarding sale transactions in the partnership
     interests in this table is provided without verification by Pioneer USA and
     because the information provided does not reflect sufficient activity to
     cause the prices shown to be representative of the market values of the
     partnership interests, the information should not be relied upon as
     indicative of the ability of limited partners to sell their partnership
     interests in secondary sale transactions or as to the prices at which the
     partnership interests may be sold.



                                      A-16

   110
                                   APPENDIX B
                                       TO
                           PROXY STATEMENT/PROSPECTUS

                            SUMMARY RESERVE REPORT OF
                     WILLIAMSON PETROLEUM CONSULTANTS, INC.
                              FOR THE PARTNERSHIPS

April 10, 2001




Pioneer Natural Resources USA, Inc.
5205 North O'Connor Boulevard, Suite 1400
Irving, Texas  75039

Attention Board of Directors

Gentlemen:

Subject: Letter Report Including 46 Reports Prepared
     by Williamson Petroleum Consultants, Inc.
     for Pioneer Natural Resources USA, Inc.
     to the Interests of Limited Partners
     or the Converted Limited Partners
     in Various Parker & Parsley Partnerships
     Managed by Pioneer Natural Resources USA, Inc.
     Effective December 31, 2000
     for Disclosure to the
     Securities and Exchange Commission
     Williamson Project 0.8839

In accordance with your request, Williamson Petroleum Consultants, Inc.
(Williamson) has prepared this summary letter for inclusion in the proxy
statement to be distributed to the limited partners of the referenced
partnerships by Pioneer Natural Resources USA, Inc. (Pioneer USA). This letter
includes 46 Williamson reports prepared for Pioneer USA to the interests of the
limited partners or the converted limited partners in various Parker & Parsley
partnerships managed by Pioneer USA effective December 31, 2000 for disclosure
to the Securities and Exchange Commission (SEC). A listing of the 46 Williamson
reports is included as Exhibit I.

I. ESTIMATED RESERVES AND ESTIMATED FUTURE NET REVENUES

The total Williamson estimated net proved reserves that are attributable to the
evaluated interests of the 46 partnership reports are shown in Exhibit II and
were based on economic parameters and operating condition considered applicable
as of December 31, 2000 and may be used in disclosure to the SEC.

The present values of the estimated future net revenues from proved reserves
were calculated using a discount rate of 10.00 percent per annum and were
computed in accordance with the financial reporting requirements of the SEC and
are presented in Exhibit II.


   111
Pioneer Natural Resources USA, Inc.
Board of Directors
April 10, 2001
Page 2


At the request of Pioneer USA, Williamson used the Landmark graphics and
reserves and economics evaluation software, Aries, to prepare this summary
report. In evaluations of these properties prior to December 31, 1991,
Williamson utilized its proprietary software programs. No comparative tests have
been performed to determine the difference in evaluation results of either
reserves or revenue quantities that may occur solely as a result of the
differences in the programs nor has Williamson performed tests to determine the
accuracy of Aries. However, in accordance with the request made by Pioneer USA
and the general acceptance of Aries by the oil and gas industry, Williamson has
used Aries to prepare this report.

II. DEFINITIONS OF SEC RESERVES(1)

The estimated reserves presented in this summary letter are net proved reserves,
including proved developed producing, proved developed nonproducing, and proved
undeveloped reserves, and were computed in accordance with the financial
reporting requirements of the SEC. In preparing these evaluations, no attempt
has been made to quantify the element of uncertainty associated with any
category. Reserves were assigned to each category as warranted. The definitions
of oil and gas reserves pursuant to the requirements of the Securities Exchange
Act are:

Proved Reserves(2)

Proved reserves are the estimated quantities of crude oil, natural gas, and
natural gas liquids which geological and engineering data demonstrate with
reasonable certainty to be recoverable in future years from known reservoirs
under the economic criteria employed and existing operating conditions, i.e.,
prices and costs as of the date the estimate is made. Prices and costs include
consideration of changes provided only by contractual arrangements but not on
escalations based upon an estimate of future conditions.

----------

(1) For evaluations prepared for disclosure to the Securities and Exchange
    Commission, see SEC Accounting Rules. Commerce Clearing House, Inc. October
    1981, Paragraph 290, Regulation 210.4-10, p. 329.

(2) Any variations to these definitions will be clearly stated in the report.


                                      B-2
   112
Pioneer Natural Resources USA, Inc.
Board of Directors
April 10, 2001
Page 3

A.   Reservoirs are considered proved if economic producibility is supported by
     either actual production or conclusive formation test. The area of a
     reservoir considered proved includes:

     1.   that portion delineated by drilling and defined by gas-oil and/or
          oil-water contacts, if any; and

     2.   the immediately adjoining portions not yet drilled, but which can be
          reasonably judged as economically productive on the basis of available
          geological and engineering data. In the absence of information on
          fluid contacts, the lowest known structural occurrence of hydrocarbons
          controls the lower proved limit of the reservoir.

B.   Reserves which can be produced economically through application of improved
     recovery techniques (such as fluid injection) are included in the "proved"
     classification when successful testing by a pilot project, or the operation
     of an installed program in the reservoir, provides support for the
     engineering analysis on which the project or program was based.

C.   Estimates of proved reserves do not include the following:

     1.   oil that may become available from known reservoirs but is classified
          separately as "indicated additional reserves";

     2.   crude oil, natural gas, and natural gas liquids, the recovery of which
          is subject to reasonable doubt because of uncertainty as to geology,
          reservoir characteristics, or economic factors;

     3.   crude oil, natural gas, and natural gas liquids, that may occur in
          undrilled prospects; and

     4.   crude oil, natural gas, and natural gas liquids, that may be recovered
          from oil shales, coal(3), gilsonite, and other such sources.

----------
(3) According to Staff Accounting Bulletin 85, excluding certain coalbed methane
    gas.


                                      B-3


   113
Pioneer Natural Resources USA, Inc.
Board of Directors
April 10, 2001
Page 4

Proved Developed Reserves(4)

Proved developed reserves are reserves that can be expected to be recovered
through existing wells with existing equipment and operating methods. Additional
oil and gas expected to be obtained through the application of fluid injection
or other improved recovery techniques for supplementing the natural forces and
mechanisms of primary recovery should be included as "proved developed reserves"
only after testing by a pilot project or after the operation of an installed
program has confirmed through production response that increased recovery will
be achieved.

Proved Undeveloped Reserves

Proved undeveloped reserves are reserves that are expected to be recovered from
new wells on undrilled acreage, or from existing wells where a relatively major
expenditure is required for recompletion. Reserves on undrilled acreage shall be
limited to those drilling units offsetting productive units that are reasonably
certain of production when drilled. Proved reserves for other undrilled units
can be claimed only where it can be demonstrated with certainty that there is
continuity of production from the existing productive formation. Under no
circumstances should estimates for proved undeveloped reserves be attributable
to any acreage for which an application of fluid injection or other improved
recovery technique is contemplated, unless such techniques have been proved
effective by actual tests in the area and in the same reservoir.

----------
(4) Williamson Petroleum Consultants, Inc. separates proved developed reserves
    into proved developed producing and proved developed nonproducing reserves.
    This is to identify proved developed producing reserves as those to be
    recovered from actively producing wells; proved developed nonproducing
    reserves as those to be recovered from wells or intervals within wells,
    which are completed but shut in waiting on equipment or pipeline
    connections, or wells where a relatively minor expenditure is required for
    recompletion to another zone.


                                      B-4
   114
Pioneer Natural Resources USA, Inc.
Board of Directors
April 10, 2001
Page 5


III. DISCUSSION OF SEC RESERVES

The properties evaluated in this report are located in the states of Oklahoma
and Texas with the majority of the value in the Spraberry (Trend Area) field,
Texas.

The individual projections of lease reserves and economics prepared to produce
this summary report include data that describe the production forecasts and
associated evaluation parameters such as interests, taxes, product prices,
operating costs, investments, salvage values, abandonment costs, and net profit
interests.

Net income to the evaluated interests is the future net revenue after
consideration of royalty revenue payable to others, taxes, operating expenses,
investments, salvage values, abandonment costs, and net profit interests, as
applicable. The future net revenue is before federal income tax and excludes
consideration of any encumbrances against the properties if such exist.

The future net revenue values presented in this report were based on projections
of oil and gas production. It was assumed there would be no significant delay
between the date of oil and gas production and the receipt of the associated
revenue for this production. No opinion is expressed by Williamson in this
report as to a fair market value of the evaluated properties.

Unless specifically identified and documented by Pioneer USA as having
curtailment problems, gas production trends have been assumed to be a function
of well productivity and not of market conditions. The effect of "take or pay"
clauses in gas contracts was not considered.

Oil and natural gas liquids (NGL) reserves are expressed in thousands of United
States (U.S.) barrels (MBBL) of 42 U.S. gallons. Gas volumes are expressed in
millions of cubic feet (MMCF) at 60 degrees Fahrenheit and at the legal pressure
base that prevails in the state which the reserves are located. No adjustment of
the individual gas volumes to a common pressure base has been made.

This report includes only those costs and revenues which are considered by
Pioneer USA to be directly attributable to individual leases and areas. There
could exist other revenues, overhead costs, or other costs associated with
Pioneer USA or the Limited Partners/Converted Limited Partners which are not
included in this report. Such additional costs and revenues are outside the
scope of this report. This report is not a financial statement for Pioneer USA
or the Limited Partners/Converted Limited Partners and should not be used as the
sole basis for any transaction concerning Pioneer USA, the Limited
Partners/Converted Limited Partners, or the evaluated properties.



                                      B-5
   115
Pioneer Natural Resources USA, Inc.
Board of Directors
April 10, 2001
Page 6

The reserves projections in this report are based on the use of the available
data and accepted industry engineering methods. Future changes in any
operational or economic parameters or production characteristics of the
evaluated properties could increase or decrease their reserves. Unforeseen
changes in market demand or allowables set by various regulatory agencies could
also cause actual production rates to vary from those projected. Williamson
reserves the right to alter any of the reserves projections and the associated
economics included in this evaluation in any future evaluations based on
additional data that may be acquired.

All data utilized in the preparation of this report with respect to interests,
reversionary status, oil and gas prices, gas categories, gas contract terms,
operating expenses, investments, salvage values, abandonment costs, net profit
interests, well information, and current operating conditions, as applicable,
were provided by Pioneer USA. Production data provided by Pioneer USA were
utilized. The production data was generally through October 2000. All data have
been reviewed for reasonableness and, unless obvious errors were detected, have
been accepted as correct. It should be emphasized that revisions to the
projections of reserves and economics included in this report may be required if
the provided data are revised for any reason. No inspection of the properties
was made as this was not considered within the scope of this evaluation. No
investigation was made of any environmental liabilities that might apply to the
evaluated properties, and no costs are included for any possible related
expenses.

Since sufficient production history and other data were available, the estimates
of reserves contained in this report were determined by extrapolation of
historical production trends and in accordance with the Definitions of SEC
Reserves included in this summary letter report.

Prices for oil sold as of December 31, 2000 were provided by Pioneer USA to be
used at the effective date. These prices include adjustments for API gravity,
transportation, and any bonus paid. These adjustments were made by Pioneer USA.
After the effective date, prices were held constant for the life of the
properties. No attempt has been made to account for oil price fluctuations which
have occurred in the market subsequent to the effective date of this report.

Prices for gas sold as of December 31, 2000 were provided by Pioneer USA to be
used at the effective date. These prices include adjustments for British thermal
unit content, shrinkage due to NGL removal, transportation and handling charges,
and any other known differences between sales and produced volumes. These
adjustments were made by Pioneer USA. After the effective date, prices were held
constant for the life of the properties unless Pioneer USA indicated


                                      B-6
   116
Pioneer Natural Resources USA, Inc.
Board of Directors
April 10, 2001
Page 7

that changes were provided for by contract. All gas prices were applied to
projected wellhead volumes.

Prices for NGL sold as of December 31, 2000 were provided by Pioneer USA to be
used at the effective date. NGL reserves were projected as a separate stream
using a constant ratio (barrels of NGL/thousand cubic feet of gas) based on
historical yields. After the effective date, prices were held constant for the
life of the properties. No attempt has been made to account for price
fluctuations which have occurred in the market subsequent to the effective date
of this report.

It should be emphasized that with the current economic uncertainties,
fluctuation in market conditions could significantly change the economics of the
properties included in this report.

Operating expenses were provided by Pioneer USA and represented, when possible,
the latest available 12-month average of all recurring expenses which are
billable to the working interest owners. These expenses included, but were not
limited to, all direct operating expenses, field overhead costs, and any ad
valorem taxes not deducted separately. Expenses for workovers, well
stimulations, and other maintenance were not included in the operating expenses
unless such work was expected on a recurring basis. Judgments for the exclusion
of the nonrecurring expenses were made by Pioneer USA. Operating costs were held
constant for the life of the properties.

State production and county ad valorem taxes have been deducted at the published
rates as provided by Pioneer USA. A 7.5 percent severance tax exemption was
applied until September 2001 for qualifying wells.

IV. CONSENT AND DECLARATION OF INDEPENDENT STATUS

We understand that our estimates are to be included in a Schedule 13e-3 under
the Securities Exchange Act of 1934 to be filed by you with the SEC and in the
proxy statement included as an exhibit to such Schedule 13e-3. We understand
further that the estimates may be used by you to establish merger values for the
Partnerships. With this understanding in mind, we have consistently applied the
generally accepted petroleum engineering and evaluation principles in estimating
the proved oil and gas reserves and in computing the future net revenues derived
from such reserves for each property attributable to the interests held by the
Partnerships.

Based on information supplied by Pioneer USA, neither capital costs nor salvage
values were included in the projections of reserves and economics in this
report. Williamson is an independent consulting firm and does not own any
interests in the oil and gas properties covered by this report. No employee,
officer, or director of Williamson is an employee, officer, or director of
Pioneer USA or any of the

                                      B-7
   117
Pioneer Natural Resources USA, Inc.
Board of Directors
April 10, 2001
Page 8

subject partnerships. Neither the employment of nor the compensation received by
Williamson is contingent upon the values assigned to the properties covered by
this report.

Yours very truly,

/s/ Williamson Petroleum Consultants, Inc.

WILLIAMSON PETROLEUM CONSULTANTS, INC.

JDS/chk

Enclosures

                                      B-8

   118

                                    EXHIBIT I

                   LETTER REPORT INCLUDING 46 REPORTS PREPARED
                    BY WILLIAMSON PETROLEUM CONSULTANTS, INC.
                     FOR PIONEER NATURAL RESOURCES USA, INC.
                      TO THE INTERESTS OF LIMITED PARTNERS
                        OR THE CONVERTED LIMITED PARTNERS
                    IN VARIOUS PARKER & PARSLEY PARTNERSHIPS
                 MANAGED BY PIONEER NATURAL RESOURCES USA, INC.
                           EFFECTIVE DECEMBER 31, 2000
                              FOR DISCLOSURE TO THE
                       SECURITIES AND EXCHANGE COMMISSION
                            WILLIAMSON PROJECT 0.8839

             LIST OF WILLIAMSON PETROLEUM CONSULTANTS, INC. REPORTS
                           EFFECTIVE DECEMBER 31, 2000

"Evaluation of Oil and Gas Reserves to the Interests of the Limited Partners in
Parker & Parsley 81-I, Ltd. Managed by Pioneer Natural Resources USA, Inc.
Effective December 31, 2000 for Disclosure to the Securities and Exchange
Commission Summary Report Utilizing Aries Software Williamson Project 0.8839"

"Evaluation of Oil and Gas Reserves to the Interests of the Limited Partners in
Parker & Parsley 81-II, Ltd. Managed by Pioneer Natural Resources USA, Inc.
Effective December 31, 2000 for Disclosure to the Securities and Exchange
Commission Summary Report Utilizing Aries Software Williamson Project 0.8839"

"Evaluation of Oil and Gas Reserves to the Interests of the Limited Partners in
Parker & Parsley 82-I, Ltd. Managed by Pioneer Natural Resources USA, Inc.
Effective December 31, 2000 for Disclosure to the Securities and Exchange
Commission Summary Report Utilizing Aries Software Williamson Project 0.8839"

"Evaluation of Oil and Gas Reserves to the Interests of the Limited Partners in
Parker & Parsley 82-II, Ltd. Managed by Pioneer Natural Resources USA, Inc.
Effective December 31, 2000 for Disclosure to the Securities and Exchange
Commission Summary Report Utilizing Aries Software Williamson Project 0.8839"

"Evaluation of Oil and Gas Reserves to the Interests of the Limited Partners in
Parker & Parsley 82-III, Ltd. Managed by Pioneer Natural Resources USA, Inc.
Effective December 31, 2000 for Disclosure to the Securities and Exchange
Commission Summary Report Utilizing Aries Software Williamson Project 0.8839"

"Evaluation of Oil and Gas Reserves to the Interests of the Limited Partners in
Parker & Parsley 83-A, Ltd. Managed by Pioneer Natural Resources USA, Inc.
Effective December 31, 2000 for Disclosure to the Securities and Exchange
Commission Summary Report Utilizing Aries Software Williamson Project 0.8839"

"Evaluation of Oil and Gas Reserves to the Interests of the Limited Partners in
Parker & Parsley 83-B, Ltd. Managed by Pioneer Natural Resources USA, Inc.
Effective December 31, 2000 for Disclosure to the Securities and Exchange
Commission Summary Report Utilizing Aries Software Williamson Project 0.8839"

"Evaluation of Oil and Gas Reserves to the Interests of the Limited Partners in
Parker & Parsley 84-A, Ltd. Managed by Pioneer Natural Resources USA, Inc.
Effective December 31, 2000 for Disclosure to the Securities and Exchange
Commission Summary Report Utilizing Aries Software Williamson Project 0.8839"

"Evaluation of Oil and Gas Reserves to the Interests of the Limited Partners in
Parker & Parsley 85-A, Ltd. Managed by Pioneer Natural Resources USA, Inc.
Effective December 31, 2000 for Disclosure to the Securities and Exchange
Commission Summary Report Utilizing Aries Software Williamson Project 0.8839"

"Evaluation of Oil and Gas Reserves to the Interests of the Limited Partners in
Parker & Parsley 85-B, Ltd. Managed by Pioneer Natural Resources USA, Inc.
Effective December 31, 2000 for Disclosure to the Securities and Exchange
Commission Summary Report Utilizing Aries Software Williamson Project 0.8839"


                                      B-9
   119
                                    EXHIBIT I

                   LETTER REPORT INCLUDING 46 REPORTS PREPARED
                    BY WILLIAMSON PETROLEUM CONSULTANTS, INC.
                     FOR PIONEER NATURAL RESOURCES USA, INC.
                      TO THE INTERESTS OF LIMITED PARTNERS
                        OR THE CONVERTED LIMITED PARTNERS
                    IN VARIOUS PARKER & PARSLEY PARTNERSHIPS
                 MANAGED BY PIONEER NATURAL RESOURCES USA, INC.
                           EFFECTIVE DECEMBER 31, 2000
                              FOR DISCLOSURE TO THE
                       SECURITIES AND EXCHANGE COMMISSION
                            WILLIAMSON PROJECT 0.8839

             LIST OF WILLIAMSON PETROLEUM CONSULTANTS, INC. REPORTS
                           EFFECTIVE DECEMBER 31, 2000



"Evaluation of Oil and Gas Reserves to the Interests of the Limited Partners in
Parker & Parsley Private Investment 85-A, Ltd. Managed by Pioneer Natural
Resources USA, Inc. Effective December 31, 2000 for Disclosure to the Securities
and Exchange Commission Summary Report Utilizing Aries Software Williamson
Project 0.8839"

"Evaluation of Oil and Gas Reserves to the Interests of the Limited Partners in
Parker & Parsley Selected 85 Private Investment, Ltd. Managed by Pioneer Natural
Resources USA, Inc. Effective December 31, 2000 for Disclosure to the Securities
and Exchange Commission Summary Report Utilizing Aries Software Williamson
Project 0.8839"

"Evaluation of Oil and Gas Reserves to the Interests of the Limited Partners in
Parker & Parsley 86-A, Ltd. Managed by Pioneer Natural Resources USA, Inc.
Effective December 31, 2000 for Disclosure to the Securities and Exchange
Commission Summary Report Utilizing Aries Software Williamson Project 0.8839"

"Evaluation of Oil and Gas Reserves to the Interests of the Limited Partners in
Parker & Parsley 86-B, Ltd. Managed by Pioneer Natural Resources USA, Inc.
Effective December 31, 2000 for Disclosure to the Securities and Exchange
Commission Summary Report Utilizing Aries Software Williamson Project 0.8839"

"Evaluation of Oil and Gas Reserves to the Interests of the Limited Partners in
Parker & Parsley 86-C, Ltd. Managed by Pioneer Natural Resources USA, Inc.
Effective December 31, 2000 for Disclosure to the Securities and Exchange
Commission Summary Report Utilizing Aries Software Williamson Project 0.8839"

"Evaluation of Oil and Gas Reserves to the Interests of the Limited Partners in
Parker & Parsley Private Investment 86, Ltd. Managed by Pioneer Natural
Resources USA, Inc. Effective December 31, 2000 for Disclosure to the Securities
and Exchange Commission Summary Report Utilizing Aries Software Williamson
Project 0.8839"

"Evaluation of Oil and Gas Reserves to the Interests of the Converted Limited
Partners in Parker & Parsley 87-A Converted, Ltd. Managed by Pioneer Natural
Resources USA, Inc. Effective December 31, 2000 for Disclosure to the Securities
and Exchange Commission Summary Report Utilizing Aries Software Williamson
Project 0.8839"

"Evaluation of Oil and Gas Reserves to the Interests of the Limited Partners in
Parker & Parsley 87-A, Ltd. Managed by Pioneer Natural Resources USA, Inc.
Effective December 31, 2000 for Disclosure to the Securities and Exchange
Commission Summary Report Utilizing Aries Software Williamson Project 0.8839"

"Evaluation of Oil and Gas Reserves to the Interests of the Converted Limited
Partners in Parker & Parsley 87-B Converted, Ltd. Managed by Pioneer Natural
Resources USA, Inc. Effective December 31, 2000 for Disclosure to the Securities
and Exchange Commission Summary Report Utilizing Aries Software Williamson
Project 0.8839"

"Evaluation of Oil and Gas Reserves to the Interests of the Limited Partners in
Parker & Parsley 87-B, Ltd. Managed by Pioneer Natural Resources USA, Inc.
Effective December 31, 2000 for Disclosure to the Securities and Exchange
Commission Summary Report Utilizing Aries Software Williamson Project 0.8839"



                                      B-10
   120
                                    EXHIBIT I

                   LETTER REPORT INCLUDING 46 REPORTS PREPARED
                    BY WILLIAMSON PETROLEUM CONSULTANTS, INC.
                     FOR PIONEER NATURAL RESOURCES USA, INC.
                      TO THE INTERESTS OF LIMITED PARTNERS
                        OR THE CONVERTED LIMITED PARTNERS
                    IN VARIOUS PARKER & PARSLEY PARTNERSHIPS
                 MANAGED BY PIONEER NATURAL RESOURCES USA, INC.
                           EFFECTIVE DECEMBER 31, 2000
                              FOR DISCLOSURE TO THE
                       SECURITIES AND EXCHANGE COMMISSION
                            WILLIAMSON PROJECT 0.8839

             LIST OF WILLIAMSON PETROLEUM CONSULTANTS, INC. REPORTS
                           EFFECTIVE DECEMBER 31, 2000


"Evaluation of Oil and Gas Reserves to the Interests of the Limited Partners in
Parker & Parsley Producing Properties 87-A, Ltd. Managed by Pioneer Natural
Resources USA, Inc. Effective December 31, 2000 for Disclosure to the Securities
and Exchange Commission Summary Report Utilizing Aries Software Williamson
Project 0.8839"

"Evaluation of Oil and Gas Reserves to the Interests of the Limited Partners in
Parker & Parsley Producing Properties 87-B, Ltd. Managed by Pioneer Natural
Resources USA, Inc. Effective December 31, 2000 for Disclosure to the Securities
and Exchange Commission Summary Report Utilizing Aries Software Williamson
Project 0.8839"

"Evaluation of Oil and Gas Reserves to the Interests of the Limited Partners in
Parker & Parsley Private Investment 87, Ltd. Managed by Pioneer Natural
Resources USA, Inc. Effective December 31, 2000 for Disclosure to the Securities
and Exchange Commission Summary Report Utilizing Aries Software Williamson
Project 0.8839"

"Evaluation of Oil and Gas Reserves to the Interests of the Converted Limited
Partners in Parker & Parsley 88-A Converted, L.P. Managed by Pioneer Natural
Resources USA, Inc. Effective December 31, 2000 for Disclosure to the Securities
and Exchange Commission Summary Report Utilizing Aries Software Williamson
Project 0.8839"

"Evaluation of Oil and Gas Reserves to the Interests of the Limited Partners in
Parker & Parsley 88-A, L.P. Managed by Pioneer Natural Resources USA, Inc.
Effective December 31, 2000 for Disclosure to the Securities and Exchange
Commission Summary Report Utilizing Aries Software Williamson Project 0.8839"

"Evaluation of Oil and Gas Reserves to the Interests of the Converted Limited
Partners in Parker & Parsley 88-B Converted, L.P. Managed by Pioneer Natural
Resources USA, Inc. Effective December 31, 2000 for Disclosure to the Securities
and Exchange Commission Summary Report Utilizing Aries Software Williamson
Project 0.8839"

"Evaluation of Oil and Gas Reserves to the Interests of the Limited Partners in
Parker & Parsley 88-B, L.P. Managed by Pioneer Natural Resources USA, Inc.
Effective December 31, 2000 for Disclosure to the Securities and Exchange
Commission Summary Report Utilizing Aries Software Williamson Project 0.8839"

"Evaluation of Oil and Gas Reserves to the Interests of the Converted Limited
Partners in Parker & Parsley 88-C Converted, L.P. Managed by Pioneer Natural
Resources USA, Inc. Effective December 31, 2000 for Disclosure to the Securities
and Exchange Commission Summary Report Utilizing Aries Software Williamson
Project 0.8839"

"Evaluation of Oil and Gas Reserves to the Interests of the Limited Partners in
Parker & Parsley 88-C, L.P. Managed by Pioneer Natural Resources USA, Inc.
Effective December 31, 2000 for Disclosure to the Securities and Exchange
Commission Summary Report Utilizing Aries Software Williamson Project 0.8839"

                                      B-11
   121
                                    EXHIBIT I

                   LETTER REPORT INCLUDING 46 REPORTS PREPARED
                    BY WILLIAMSON PETROLEUM CONSULTANTS, INC.
                     FOR PIONEER NATURAL RESOURCES USA, INC.
                      TO THE INTERESTS OF LIMITED PARTNERS
                        OR THE CONVERTED LIMITED PARTNERS
                    IN VARIOUS PARKER & PARSLEY PARTNERSHIPS
                 MANAGED BY PIONEER NATURAL RESOURCES USA, INC.
                           EFFECTIVE DECEMBER 31, 2000
                              FOR DISCLOSURE TO THE
                       SECURITIES AND EXCHANGE COMMISSION
                            WILLIAMSON PROJECT 0.8839

             LIST OF WILLIAMSON PETROLEUM CONSULTANTS, INC. REPORTS
                           EFFECTIVE DECEMBER 31, 2000



"Evaluation of Oil and Gas Reserves to the Interests of the Limited Partners in
Parker & Parsley Producing Properties 88-A, L.P. Managed by Pioneer Natural
Resources USA, Inc. Effective December 31, 2000 for Disclosure to the Securities
and Exchange Commission Summary Report Utilizing Aries Software Williamson
Project 0.8839"

"Evaluation of Oil and Gas Reserves to the Interests of the Limited Partners in
Parker & Parsley Private Investment 88, L.P. Managed by Pioneer Natural
Resources USA, Inc. Effective December 31, 2000 for Disclosure to the Securities
and Exchange Commission Summary Report Utilizing Aries Software Williamson
Project 0.8839"

"Evaluation of Oil and Gas Reserves to the Interests of the Converted Limited
Partners in Parker & Parsley 89-A Converted, L.P. Managed by Pioneer Natural
Resources USA, Inc. Effective December 31, 2000 for Disclosure to the Securities
and Exchange Commission Summary Report Utilizing Aries Software Williamson
Project 0.8839"

"Evaluation of Oil and Gas Reserves to the Interests of the Limited Partners in
Parker & Parsley 89-A, L.P. Managed by Pioneer Natural Resources USA, Inc.
Effective December 31, 2000 for Disclosure to the Securities and Exchange
Commission Summary Report Utilizing Aries Software Williamson Project 0.8839"

"Evaluation of Oil and Gas Reserves to the Interests of the Converted Limited
Partners in Parker & Parsley 89-B Converted, L.P. Managed by Pioneer Natural
Resources USA, Inc. Effective December 31, 2000 for Disclosure to the Securities
and Exchange Commission Summary Report Utilizing Aries Software Williamson
Project 0.8839"

"Evaluation of Oil and Gas Reserves to the Interests of the Limited Partners in
Parker & Parsley 89-B, L.P. Managed by Pioneer Natural Resources USA, Inc.
Effective December 31, 2000 for Disclosure to the Securities and Exchange
Commission Summary Report Utilizing Aries Software Williamson Project 0.8839"

"Evaluation of Oil and Gas Reserves to the Interests of the Limited Partners in
Parker & Parsley Private Investment 89, L.P. Managed by Pioneer Natural
Resources USA, Inc. Effective December 31, 2000 for Disclosure to the Securities
and Exchange Commission Summary Report Utilizing Aries Software Williamson
Project 0.8839"

"Evaluation of Oil and Gas Reserves to the Interests of the Converted Limited
Partners in Parker & Parsley 90-A Converted, L.P. Managed by Pioneer Natural
Resources USA, Inc. Effective December 31, 2000 for Disclosure to the Securities
and Exchange Commission Summary Report Utilizing Aries Software Williamson
Project 0.8839"

"Evaluation of Oil and Gas Reserves to the Interests of the Limited Partners in
Parker & Parsley 90-A, L.P. Managed by Pioneer Natural Resources USA, Inc.
Effective December 31, 2000 for Disclosure to the Securities and Exchange
Commission Summary Report Utilizing Aries Software Williamson Project 0.8839"


                                      B-12
   122
                                    EXHIBIT I

                   LETTER REPORT INCLUDING 46 REPORTS PREPARED
                    BY WILLIAMSON PETROLEUM CONSULTANTS, INC.
                     FOR PIONEER NATURAL RESOURCES USA, INC.
                      TO THE INTERESTS OF LIMITED PARTNERS
                        OR THE CONVERTED LIMITED PARTNERS
                    IN VARIOUS PARKER & PARSLEY PARTNERSHIPS
                 MANAGED BY PIONEER NATURAL RESOURCES USA, INC.
                           EFFECTIVE DECEMBER 31, 2000
                              FOR DISCLOSURE TO THE
                       SECURITIES AND EXCHANGE COMMISSION
                            WILLIAMSON PROJECT 0.8839

             LIST OF WILLIAMSON PETROLEUM CONSULTANTS, INC. REPORTS
                           EFFECTIVE DECEMBER 31, 2000



"Evaluation of Oil and Gas Reserves to the Interests of the Converted Limited
Partners in Parker & Parsley 90-B Converted, L.P. Managed by Pioneer Natural
Resources USA, Inc. Effective December 31, 2000 for Disclosure to the Securities
and Exchange Commission Summary Report Utilizing Aries Software Williamson
Project 0.8839"

"Evaluation of Oil and Gas Reserves to the Interests of the Limited Partners in
Parker & Parsley 90-B, L.P. Managed by Pioneer Natural Resources USA, Inc.
Effective December 31, 2000 for Disclosure to the Securities and Exchange
Commission Summary Report Utilizing Aries Software Williamson Project 0.8839"

"Evaluation of Oil and Gas Reserves to the Interests of the Converted Limited
Partners in Parker & Parsley 90-C Converted, L.P. Managed by Pioneer Natural
Resources USA, Inc. Effective December 31, 2000 for Disclosure to the Securities
and Exchange Commission Summary Report Utilizing Aries Software Williamson
Project 0.8839"

"Evaluation of Oil and Gas Reserves to the Interests of the Limited Partners in
Parker & Parsley 90-C, L.P. Managed by Pioneer Natural Resources USA, Inc.
Effective December 31, 2000 for Disclosure to the Securities and Exchange
Commission Summary Report Utilizing Aries Software Williamson Project 0.8839"

"Evaluation of Oil and Gas Reserves to the Interests of the Limited Partners in
Parker & Parsley Private Investment 90, L.P. Managed by Pioneer Natural
Resources USA, Inc. Effective December 31, 2000 for Disclosure to the Securities
and Exchange Commission Summary Report Utilizing Aries Software Williamson
Project 0.8839"

"Evaluation of Oil and Gas Reserves to the Interests of the Limited Partners in
Parker & Parsley 90 Spraberry Private Development, L.P. Managed by Pioneer
Natural Resources USA, Inc. Effective December 31, 2000 for Disclosure to the
Securities and Exchange Commission Summary Report Utilizing Aries Software
Williamson Project 0.8839"

"Evaluation of Oil and Gas Reserves to the Interests of the Limited Partners in
Parker & Parsley 91-A, L.P. Managed by Pioneer Natural Resources USA, Inc.
Effective December 31, 2000 for Disclosure to the Securities and Exchange
Commission Summary Report Utilizing Aries Software Williamson Project 0.8839"

"Evaluation of Oil and Gas Reserves to the Interests of the Limited Partners in
Parker & Parsley 91-B, L.P. Managed by Pioneer Natural Resources USA, Inc.
Effective December 31, 2000 for Disclosure to the Securities and Exchange
Commission Summary Report Utilizing Aries Software Williamson Project 0.8839"


                                      B-13
   123

                                   EXHIBIT II

                   LETTER REPORT INCLUDING 46 REPORTS PREPARED
                    BY WILLIAMSON PETROLEUM CONSULTANTS, INC.
                     FOR PIONEER NATURAL RESOURCES USA, INC.
                      TO THE INTERESTS OF LIMITED PARTNERS
                        OR THE CONVERTED LIMITED PARTNERS
                    IN VARIOUS PARKER & PARSLEY PARTNERSHIPS
                 MANAGED BY PIONEER NATURAL RESOURCES USA, INC.
                           EFFECTIVE DECEMBER 31, 2000
                              FOR DISCLOSURE TO THE
                       SECURITIES AND EXCHANGE COMMISSION
                            WILLIAMSON PROJECT 0.8839

                       NET RESERVES AND FUTURE NET REVENUE
         FROM REPORTS PREPARED BY WILLIAMSON PETROLEUM CONSULTANTS, INC.
                           EFFECTIVE DECEMBER 31, 2000




                                                                    TOTAL PROVED DEVELOPED PRODUCING
                                        ------------------------------------------------------------------------------
                                                                                             FUTURE NET REVENUE, M$
                                                                                         -----------------------------
                                                        NET RESERVES TO
                                                    THE EVALUATED INTERESTS                                DISCOUNTED
                                        ---------------------------------------------                         PER
                                        OIL/CONDENSATE      LIQUID            GAS                          ANNUM AT
PIONEER FUNDS                                (MBBL)         (MBBL)           (MMCF)      UNDISCOUNTED    10.00 PERCENT
                                        --------------   ------------    ------------    ------------    -------------
                                                                                          
Parker & Parsley 81-I, Ltd                     99.997          58.388         320.081       2,810.911       1,436.523

Parker & Parsley 81-II, Ltd.                   84.731          67.440         222.749       1,977.257       1,062.283

Parker & Parsley 82-I, Ltd.                   194.780          73.613         603.859       4,656.049       2,419.619

Parker & Parsley 82-II, Ltd.                  211.725          94.426         467.740       4,879.008       2,416.761

Parker & Parsley 82-III, Ltd.                 164.851          68.468         223.717       2,916.207       1,539.389

Parker & Parsley 83-A, Ltd.                   497.915         281.533       1,156.089      11,168.739       5,649.205

Parker & Parsley 83-B, Ltd.                   608.901         345.775       1,553.450      14,112.492       7,165.928

Parker & Parsley 84-A, Ltd.                   608.956         403.376       1,678.388      15,623.823       7,676.646

Parker & Parsley 85-A, Ltd.                   243.615         134.904         512.744       5,195.717       2,783.387

Parker & Parsley 85-B, Ltd.                   201.444          99.966         455.062       4,490.151       2,308.454

Parker & Parsley Private
  Investment 85-A, Ltd.                       228.363          96.999         353.440       5,194.664       2,383.495

Parker & Parsley Selected
  85 Private Investment, Ltd.                 130.193          99.486         381.116       3,650.520       1,810.634

Parker & Parsley 86-A, Ltd.                   250.327         197.841         859.633       7,179.394       3,574.162

Parker & Parsley 86-B, Ltd.                   618.084         308.191       1,200.966      14,120.080       7,029.228

Parker & Parsley 86-C, Ltd.                   563.752         325.531       1,246.684      11,898.910       6,501.998

Parker & Parsley Private
  Investment 86, Ltd.                         208.138         106.060         491.002       4,920.619       2,468.192

Parker & Parsley 87-A Conv., Ltd.             113.696          66.277         287.292       2,873.802       1,450.827

Parker & Parsley 87-A, Ltd.                   834.588         487.044       2,112.270      21,154.029      10,747.196

Parker & Parsley 87-B Conv., Ltd.             157.541          88.713         365.167       3,907.545       1,832.825

Parker & Parsley 87-B, Ltd.                   643.391         362.299       1,491.327      15,958.265       7,485.189

Parker & Parsley Producing
  Properties 87-A, Ltd.                       553.134         153.947         705.887       9,228.521       4,636.341

Parker & Parsley Producing
  Properties 87-B, Ltd.                       348.562         183.827         852.462       9,400.038       4,368.675

Parker & Parsley Private
  Investment 87, Ltd.                         525.646         229.811         959.391      12,336.452       5,141.312

Parker & Parsley 88-A Conv., L.P.             144.189          81.404         314.160       3,480.240       1,705.478

Parker & Parsley 88-A, L.P.                   491.675         277.590       1,071.291      11,868.418       5,816.075

Parker & Parsley 88-B Conv., L.P.             185.600          84.916         353.516       4,354.398       2,077.136

Parker & Parsley 88-B, L.P.                   457.018         209.116         870.573      10,723.127       5,115.146

Parker & Parsley 88-C Conv., L.P.             145.815          74.419         309.894       3,561.005       1,706.767


                                      B-14
   124
                                   EXHIBIT II

                   LETTER REPORT INCLUDING 46 REPORTS PREPARED
                    BY WILLIAMSON PETROLEUM CONSULTANTS, INC.
                     FOR PIONEER NATURAL RESOURCES USA, INC.
                      TO THE INTERESTS OF LIMITED PARTNERS
                        OR THE CONVERTED LIMITED PARTNERS
                    IN VARIOUS PARKER & PARSLEY PARTNERSHIPS
                 MANAGED BY PIONEER NATURAL RESOURCES USA, INC.
                           EFFECTIVE DECEMBER 31, 2000
                              FOR DISCLOSURE TO THE
                       SECURITIES AND EXCHANGE COMMISSION
                            WILLIAMSON PROJECT 0.8839

                       NET RESERVES AND FUTURE NET REVENUE
         FROM REPORTS PREPARED BY WILLIAMSON PETROLEUM CONSULTANTS, INC.
                           EFFECTIVE DECEMBER 31, 2000





                                                                    TOTAL PROVED DEVELOPED PRODUCING
                                        ------------------------------------------------------------------------------
                                                                                             FUTURE NET REVENUE, M$
                                                                                         -----------------------------
                                                        NET RESERVES TO
                                                    THE EVALUATED INTERESTS                                DISCOUNTED
                                        ---------------------------------------------                         PER
                                        OIL/CONDENSATE      LIQUID            GAS                          ANNUM AT
PIONEER FUNDS                                (MBBL)         (MBBL)           (MMCF)      UNDISCOUNTED    10.00 PERCENT
                                        --------------   ------------    ------------    ------------    -------------
                                                                                          
Parker & Parsley 88-C, L.P.                   103.921          53.036         220.852       2,537.908       1,216.403

Parker & Parsley Producing
  Properties 88-A, L.P.                       273.838         149.368         558.886       6,727.211       3,225.257

Parker & Parsley Private
  Investment 88, L.P.                         509.333         253.748         928.143      12,668.293       5,826.092

Parker & Parker 89-A Conv., L.P.              136.107          64.524         282.306       3,433.908       1,667.718

Parker & Parsley 89-A, L.P.                   404.668         191.841         839.377      10,210.849       4,959.027

Parker & Parsley 89-B Conv., L.P.             276.640         159.018         597.289       6,717.103       3,379.724

Parker & Parsley 89-B, L.P.                   304.369         175.038         657.490       7,386.746       3,718.741

Parker & Parsley Private
  Investment 89, L.P.                         324.948         138.741         489.327       6,929.194       3,302.639

Parker & Parsley 90-A Conv., L.P.              86.964          46.820         168.458       2,004.818       1,042.228

Parker & Parsley 90-A, L.P.                   253.836         136.323         490.071       5,806.774       3,011.223

Parker & Parsley 90-B Conv., L.P.             503.298         242.511         965.950      11,527.923       5,694.202

Parker & Parsley 90-B, L.P.                 1,370.202         658.317       2,621.779      31,316.135      15,461.210

Parker & Parsley 90-C Conv., L.P.             323.794         138.198         463.058       6,302.167       3,212.933

Parker & Parsley 90-C, L.P.                   520.528         222.164         744.398      10,131.499       5,165.181

Parker & Parsley Private
  Investment 90, L.P.                         584.599         228.964         801.496      12,370.155       5,691.401

Parker & Parsley 90
  Spraberry Private Development, L.P.         313.028         100.516         377.597       5,906.691       2,549.362

Parker & Parsley 91-A, L.P.                   662.796         306.258       1,409.517      17,786.756       8,134.929

Parker & Parsley 91-B, L.P.                   719.664         311.695       1,213.315      17,109.740       8,280.085
                                         ------------    ------------    ------------    ------------    ------------
Total All Partnerships                     17,189.160       8,638.440      35,249.259     400,514.251     195,847.226


                                      B-15


   125

                                   APPENDIX C
                                       TO
                           PROXY STATEMENT/PROSPECTUS

                                     FORM OF
                FAIRNESS OPINION OF ROBERT A. STANGER & CO., INC.
                               (SUBJECT TO CHANGE)

                                                                      , 2001

Board of Directors of
Pioneer Natural Resources USA, Inc.,
As the Sole or Managing General Partner of
The Partnerships Identified on Exhibit I
1400 Williams Square West
5205 North O'Connor Boulevard
Irving, Texas 75039

Gentlemen:

         Pioneer Natural Resources USA, Inc. ("Pioneer USA"), the sole or
managing general partner of the partnerships identified in Exhibit I attached
hereto ("the Partnerships"), has advised us that the Partnerships are
contemplating a transaction (the "Transaction") pursuant to an agreement (the
"Merger Agreement") in which the Partnerships will merge with and into Pioneer
USA and the interests of the limited partners (the "Limited Partners") in each
Partnership will be converted into the right to receive cash and shares of
common stock (the "Pioneer Shares") of Pioneer Natural Resources Company
("Pioneer") equal to the estimated value of such Partnership's oil and gas
reserves (the "Reserve Value") and net working capital (the "Working Capital
Balance") as of March 31, 2001 (collectively, the Reserve Value and the Working
Capital Balance are referred to herein as the "Merger Value"). We have been
advised that the Merger Value will be allocated and paid to holders of limited
partnership interests (the "Limited Partner Interests") of each Partnership in
accordance with the provisions of the Partnership agreement of each Partnership
relating to a liquidation of the Partnership.

         We have been further advised that the Reserve Value has been
established by Pioneer USA and its parent company, Pioneer, based upon the
present value of estimated future net revenues (after certain expenses and
charges) from each Partnership's proved oil and gas reserves as of March 31,
2001 utilizing prices for 2001, 2002, 2003, 2004 and thereafter of $26.17,
$24.36, $22.83, $22.31 and $21.97 per barrel of oil and $5.18, $4.61, $4.16,
$4.09 and $4.12 per thousand cubic feet of gas, and a discount rate of 13.5%. We
have been further advised that the Reserve Value is based upon the reserve
report of Williamson Petroleum Consultants, Inc. ("Williamson"), an independent
petroleum engineering firm, as of December 31, 2000, which Pioneer and Pioneer
USA have adjusted since that date through March 31, 2001 based upon a production
curve consistent with the production curve used by Williamson and to which
Pioneer and Pioneer USA have applied the prices previously stated (the "Reserve
Analysis").

         We have been advised that the Limited Partners in each Partnership will
have the opportunity to approve or reject the participation by their Partnership
in the Transaction pursuant


                                      C-1
   126

to a proxy statement/prospectus (the "Proxy Statement/Prospectus") and a Limited
Partners meeting which will be prepared and held, respectively, in connection
with the Transaction, and further that Limited Partners in each Partnership, in
exchange for Limited Partner Interests, will receive the allocated Merger Value,
25% in cash and 75% in Pioneer Shares, respectively. We have been advised that
the value to be ascribed to each share of Pioneer, which is listed on the New
York Stock Exchange ("NYSE"), shall be equal to the average closing price for
such shares on the NYSE for the ten trading day period ending three business
days prior to the meeting of the Limited Partners contemplated herein.

         You have requested that Robert A. Stanger & Co., Inc. ("Stanger")
provide an opinion as to the fairness from a financial point of view to the
unaffiliated Limited Partners of each Partnership and the unaffiliated limited
partners of the non-managing general partner of each applicable Partnership of
the Merger Value ascribed to each Partnership and the allocation thereof to: (i)
the Limited Partners of each Partnership, as a group; (ii) the general partners
of each Partnership as a group; (iii) Pioneer USA, as the managing or sole
general partner of each partnership; (iv) the unaffiliated Limited Partners of
each Partnership, as a group; and (v) the unaffiliated limited partners of the
non-managing general partner of each applicable Partnership as a group.

         Stanger, founded in 1978, has provided research, investment banking and
consulting services to clients located throughout the United States, including
major New York Stock Exchange member firms and insurance companies and over
seventy companies engaged in the management and operations of partnerships. The
investment banking activities of Stanger include financial advisory services,
asset and securities valuations, industry and company research and analysis,
litigation support and expert witness services, and due diligence investigations
in connection with both publicly registered and privately placed securities
transactions.

         Stanger, as part of its investment banking business, is regularly
engaged in the valuation of securities in connection with mergers, acquisitions,
and reorganizations and for estate, tax, corporate and other purposes. In
particular, Stanger's valuation practice principally involves partnerships,
partnership securities and assets typically owned through partnerships
including, but not limited to, oil and gas reserves, real estate, mortgages
secured by real estate, cable television systems, and equipment leasing assets.

         In arriving at the opinion set forth below, we have:

         o        Reviewed the Preliminary Proxy Statement/Prospectus;

         o        Reviewed a draft of the Merger Agreement which Pioneer USA has
                  indicated to be in substantially the form which will be
                  executed in connection with the Transaction;

         o        Reviewed the financial statements and forms 10K and 10Q, as
                  applicable, of the Partnerships for the years ended December
                  31, 1998, 1999 and 2000, and [the three months ended March 31,
                  2001];


                                      C-2
   127

         o        Reviewed the Reserve Analysis of each Partnership prepared by
                  Pioneer USA and Pioneer as of March 31, 2001;

         o        Reviewed the Reserve Report for each Partnership prepared by
                  Williamson Petroleum Consultants, Inc. as of December 31,
                  2000;

         o        Reviewed the calculations prepared by Pioneer USA and Pioneer
                  of the Merger Value per $1,000 original investment in each
                  Partnership;

         o        Reviewed Pioneer USA's analysis of other alternatives to the
                  Transaction including going concern value, liquidation value,
                  royalty trust and production payment;

         o        Reviewed estimates prepared by Pioneer USA and Pioneer of the
                  going-concern value and liquidation value per $1,000 original
                  investment in each Partnership;

         o        Interviewed key management personnel of Pioneer USA regarding
                  the oil and gas reserves, the financial condition of each
                  Partnership and the terms of the Transaction;

         o        Reviewed the financial statements of Pioneer for the years
                  ended December 31, 1999 and 2000 and the [three months ended
                  March 31, 2001];

         o        Reviewed pro forma financial data for Pioneer assuming the
                  completion of the transaction;

         o        Reviewed recent secondary market trading activity for
                  interests in the Partnerships, as available;

         o        Reviewed recent trading activity in Pioneer Shares; and

         o        Conducted such other studies, analyses, inquiries and
                  investigations as we deemed appropriate.

         In rendering this opinion, we have relied, without independent
verification, on the accuracy and completeness in all material respects of all
financial and other information that was furnished or otherwise communicated to
us by Pioneer USA, Pioneer and the Partnerships. We have been advised by Pioneer
USA and Pioneer that the oil and gas properties owned by the Partnerships are
subject to operating agreements (the "Operating Agreements") with Pioneer USA
and that: (i) such Operating Agreements provide for the payment of overhead
charges and that such charges are reasonable compared to amounts charged for
similar services by third-party operators; and (ii) except for cause, such
Operating Agreements do not provide for the termination of Pioneer USA as
operator, and (iii) such Operating Agreements do not provide for the revision of
overhead charges, except as escalated under the terms of such Operating
Agreements. Furthermore, we have been advised by Pioneer USA and Pioneer that if
each Partnership's reserves were offered for sale to a third party, a condition
of such sale would be that the oil and gas reserves would continue to be subject
to the Operating Agreements with Pioneer USA which provide for the payment of
overhead charges, and that it would be



                                      C-3
   128

appropriate to assume, when estimating the value of such reserves, that such
charges would continue. We have also been advised that the Reserve Value and
Working Capital Balance of each Partnership has been properly allocated between
Pioneer USA, the other general partners, if any, and Limited Partners of each
Partnership in accordance with the Partnership Agreement with respect to a
liquidation of such Partnership.

         We have not performed an independent appraisal of the oil and gas
reserves or other assets and liabilities of the Partnerships. We have not
conducted any engineering studies and have relied on estimates of Pioneer USA
and Pioneer with respect to oil and gas reserve volumes, prices, operating
costs, and overhead charges.

         We have relied on the assurance of Pioneer USA, Pioneer and the
Partnerships that: (i) the Reserve Analysis provided to us was in the judgment
of Pioneer USA and the Partnerships reasonably prepared on bases consistent with
actual historical experience and reflect their best currently available
estimates and good faith judgments; (ii) any estimates of costs to remediate
environmental conditions included in the Reserve Analysis are based on detailed
analyses and reflect the best currently available estimates and good faith
judgments; (iii) any historical financial data, balance sheet data, transaction
cost estimates, Merger Value analyses, going-concern value analyses and
liquidation value analyses are accurate and complete in all material respects;
(iv) all allocations included within the calculations of Merger Values,
going-concern values and liquidation values have been made in accordance with
the Partnership Agreement for each Partnership; (v) no material changes have
occurred in the information reviewed or in the value of the oil and gas reserves
or Working Capital Balances of each Partnership between the date the information
was provided to us and the date of this letter; (vi) the relative ownership
interest of the Limited Partners, unaffiliated Limited Partners, general
partners, unaffiliated limited partners of the non-managing general partner of
each applicable Partnership and Pioneer USA, as manager or sole general partner,
is accurately included in accordance with the Partnership Agreements on the
analyses provided to us by Pioneer USA; (vii) neither Pioneer or any of its
affiliates has during the thirty days prior to the date hereof commenced or
continued a share repurchase program or similar transaction which could affect
the Pioneer Share price to be used in the Transaction; and (viii) Pioneer USA,
Pioneer and the Partnerships are not aware of any information or facts regarding
the Partnerships, the oil and gas properties, the Reserve Analysis or the
Working Capital Balances of each Partnership that would cause the information
supplied to us to be incomplete or misleading in any material respect.

         We have not been requested to, and therefore did not: (i) make any
recommendation to Pioneer USA, the Partnerships or the Limited Partners with
respect to whether to approve or reject the Transaction; (ii) determine or
negotiate the amount or form of the Merger Value to be paid for Limited Partner
Interests in the Transaction; (iii) offer the assets of the Partnerships for
sale to any third party; (iv) express any opinion as to: (a) the impact of the
Transaction with respect to Pioneer USA or the Limited Partners of any
Partnerships that do not participate in the Transaction; (b) the tax
consequences of the Transaction for Pioneer USA, other general partners or the
Limited Partners of any Partnership; (c) Pioneer USA's or Pioneer's ability to
finance their obligations pursuant to the Merger Agreement or the impact of a
failure to obtain financing on the financial performance of Pioneer USA, Pioneer
or the Partnerships; (d) Pioneer USA's decision to estimate the Reserve Value of
the oil and gas reserves of each Partnership based upon the continued operation
of the properties by Pioneer USA and the payment of overhead charges in
accordance with existing Operating Agreements or the impact, if any, on the
estimated values


                                      C-4
   129

of the Partnerships' oil and gas reserves if Pioneer USA and Pioneer determined
to offer or operate the assets subject to revised Operating Agreements; (e)
whether or not alternative methods of determining the Merger Value would have
also provided fair results or results substantially similar to the methodology
used; (f) alternatives to the Transaction, including the offering of such assets
for sale to third-party buyers; (g) the trading price of Pioneer Shares
immediately following the closing of the Transaction and the distribution of
Pioneer Shares in connection therewith; (h) the fairness of the termination of
the repurchase obligations of Pioneer USA with respect to those partnerships
wherein Pioneer USA is obligated to offer to repurchase limited partnership
interests annually based upon a formula which, in certain circumstances
including the repurchase offers based upon December 31, 2000 oil and gas prices,
result in repurchase offer prices above the market value for the reserves of
such Partnerships; or (i) any other terms of the Transaction.

         This letter does not purport to be a complete description of the
analyses performed or the matters considered in rendering this opinion. The
analyses and the summary set forth herein must be considered as a whole, and
selecting portions of such summary or analyses without considering all factors
and analyses would create an incomplete view of the process underlying this
opinion. In rendering this opinion, judgment was applied to a variety of complex
analyses and assumptions. The assumptions made and the judgments applied in
rendering the opinion are not readily susceptible to partial analysis or summary
description. The fact that any specific analysis is referred to herein is not
meant to indicate that such analysis was given greater weight than any other
analyses.

         Our opinion is based on business, economic, oil and gas market, and
other conditions as of the date of our analysis and addresses the Merger Value
in the context of information available as of the date of our analysis. Events
occurring after that date could affect the value of the assets of the
Partnerships or the assumptions used in preparing this opinion.

         Based upon and subject to the foregoing, it is our opinion that, as of
the date of this letter and subject to the assumptions, limitations and
qualifications contained herein, the Merger Value ascribed to each Partnership
in connection with the Transaction and the allocation thereof to: (i) the
Limited Partners of each Partnership, as a group; (ii) the general partners of
each Partnership, as a group; (iii) Pioneer USA, as the managing or sole general
partner of each Partnership; (iv) the unaffiliated Limited Partners of each
Partnership, as a group; and (v) the unaffiliated limited partners of the
non-managing general partner of each applicable Partnership, as a group; is fair
to the unaffiliated Limited Partners of each Partnership and the unaffiliated
limited partners of the non-managing general partner of each applicable
Partnership, from a financial point of view.


Yours truly,


Robert A. Stanger & Co., Inc.
Shrewsbury, New Jersey
        , 2001


                                      C-5
   130


                                                                       EXHIBIT I

                                  PARTNERSHIPS


Parker & Parsley 81-I, Ltd.
Parker & Parsley 81-II, Ltd.
Parker & Parsley 82-I, Ltd.
Parker & Parsley 82-II, Ltd.
Parker & Parsley 82-III, Ltd.
Parker & Parsley 83-A, Ltd.
Parker & Parsley 83-B, Ltd.
Parker & Parsley 84-A, Ltd.
Parker & Parsley 85-A, Ltd.
Parker & Parsley 85-B, Ltd.
Parker & Parsley Private Investment 85-A, Ltd.
Parker & Parsley Selected 85 Private Investment, Ltd.
Parker & Parsley 86-A, Ltd.
Parker & Parsley 86-B, Ltd.
Parker & Parsley 86-C, Ltd.
Parker & Parsley Private Investment 86, Ltd.
Parker & Parsley 87-A Conv., Ltd.
Parker & Parsley 87-A, Ltd.
Parker & Parsley 87-B Conv., Ltd.
Parker & Parsley 87-B, Ltd.
Parker & Parsley Producing Properties 87-A, Ltd.
Parker & Parsley Producing Properties 87-B, Ltd.
Parker & Parsley Private Investment 87, Ltd.
Parker & Parsley 88-A Conv., Ltd.
Parker & Parsley 88-A, L.P.
Parker & Parsley 88-B Conv., L.P.
Parker & Parsley 88-B, L.P.
Parker & Parsley 88-C Conv., L.P.
Parker & Parsley 88-C, L.P.
Parker & Parsley Producing Properties 88-A, L.P.
Parker & Parsley Private Investment 88, L.P.
Parker & Parsley 89-A Conv., L.P.
Parker & Parsley 89-A, L.P.
Parker & Parsley 89-B Conv., L.P.
Parker & Parsley 89-B, L.P.
Parker & Parsley Private Investment 89, L.P.
Parker & Parsley 90-A Conv., L.P.
Parker & Parsley 90-A, L.P.
Parker & Parsley 90-B Conv., L.P.
Parker & Parsley 90-B, L.P.
Parker & Parsley 90-C Conv., L.P.
Parker & Parsley 90-C, L.P.
Parker & Parsley Private Investment 90, L.P.
Parker & Parsley 90 Spraberry Private Development, L.P.
Parker & Parsley 91-A, L.P.
Parker & Parsley 91-B, L.P.


                                      C-6
   131

                                   APPENDIX D

                                       TO

                           PROXY STATEMENT/PROSPECTUS

                              THE MERGER PROPOSALS

     The merger proposals for each partnership, except as otherwise indicated,
are set forth below. For each partnership, the merger proposals include the
approval of:

     o    the merger agreement for that partnership, pursuant to which:

          --   the partnership will be merged with and into Pioneer USA, on the
               terms and subject to the conditions set forth in the merger
               agreement as described in the proxy statement/prospectus; and

          --   each partner, whether limited or general, but other than Pioneer
               USA, will receive Pioneer common stock and cash in an amount
               based on the merger value of that partnership in exchange for
               that partner's partnership interests;

     o    the merger amendment for that partnership authorizing:

          --   the merger of the partnership with and into Pioneer USA, with
               Pioneer USA being the surviving entity; and

          --   the elimination of any restrictions on the merger otherwise
               contained in the partnership's partnership agreement; and

     o    the opinion of special legal counsel for the limited partners and the
          selection of that counsel.

     For each partnership, approval of the merger proposals requires the
affirmative vote of limited partners who own or have the power to vote a
majority, or 66?% for Parker & Parsley 91-A, L.P. and Parker & Parsley 91-B,
L.P., of the limited partnership interests in that partnership. The effect of an
abstention or a failure to vote is the same as a vote against the merger
proposals. See "The Special Meetings -- Record Date; Voting Rights and Proxies."
Subject to the terms and conditions of the merger of each partnership as
described in the proxy statement/prospectus under "The Merger Agreement," if the
merger proposals are approved by a partnership, that participating partnership
will merge with and into Pioneer USA, with Pioneer USA being the surviving
entity. From and after the closing of the merger of each participating
partnership, the partnership interests of the partners in that partnership will
represent the right to receive an amount of Pioneer common stock and cash as
described in the proxy statement/prospectus.

     Generally, the partnership agreement of each partnership requires that
special legal counsel for the limited partners, acceptable to the partnership,
deliver a legal opinion, acceptable to the partnership, that (1) neither the
grant nor the exercise of the right to approve the merger of the partnership by
its limited partners will adversely affect the federal income tax classification
of the partnership or any of its limited partners and (2) neither the grant nor
exercise of such right will result in the loss of any limited partner's limited
liability. of Dallas, Texas has delivered that opinion, subject to the approval
of the limited partners of that opinion and the selection of special legal
counsel for the limited partners. See "The Merger of Each Partnership -- Legal
Opinion for Limited Partners."

APPROVAL OF MERGER FOR EACH PARTNERSHIP FORMED IN TEXAS:

     RESOLVED: That, subject to receipt of a favorable opinion of special legal
counsel for the limited partners as described in the proxy statement/prospectus,
the partnership be merged with and into Pioneer USA, with Pioneer USA being the
surviving entity, and that an amount of Pioneer common stock and cash be paid to
each partner, other than Pioneer USA, in accordance with the terms set forth in
the merger agreement included as Appendix E to the proxy statement/prospectus
and subject to the conditions set forth therein.


                                      D-1
   132

     RESOLVED: That, subject to receipt of a favorable opinion of special legal
counsel for the limited partners as described in the proxy statement/prospectus,
the following new article shall be added to the partnership agreement of the
partnership:

                                     ARTICLE

               Notwithstanding any provisions of this Agreement to the contrary,
          it is hereby agreed as follows:

               1. Definitions. For the purposes of this Article, "Proxy
          Statement/Prospectus" means the proxy statement/prospectus dated     ,
          2001 of Pioneer Natural Resources Company, a Delaware corporation
          ("Pioneer"), and Pioneer Natural Resources USA, Inc., a Delaware
          corporation ("Pioneer USA"), contained in the Registration Statement
          on Form S-4 of Pioneer filed with the Securities and Exchange
          Commission.

               2. Elimination of Restrictions to Transaction. Notwithstanding
          anything in this Agreement to the contrary, upon the consent of
          limited partners holding a majority of the outstanding limited
          partnership interests in the partnership, which consent may or may not
          be the same consent to the adoption of an amendment to this Agreement,
          no provision of this Agreement shall prohibit, limit or prevent:

                    (a) the merger or consolidation of the partnership,
               including the merger described in the Proxy Statement/Prospectus,
               with any other domestic limited partnership or other entity, as
               those terms are defined in the Texas Revised Limited Partnership
               Act, and

                    (b) the consummation of the merger of the partnership as
               described in the Proxy Statement/Prospectus.

          In addition, no consent of the partnership, Pioneer USA or any partner
          or other procedure, including the delivery of opinions of counsel,
          shall be required in order to enable the partnership, Pioneer USA or
          any partner to effect the merger.

               3. Mergers. For purposes of this Agreement, each merger described
          in the Proxy Statement/Prospectus shall be treated as if the
          partnership has:

                    (a) disposed of all of its assets and liabilities to Pioneer
               USA in exchange for an amount in cash representing the merger
               value of the partnership, and

                    (b) liquidated in the manner provided in the liquidation
               provisions of this Agreement.

          Accordingly, upon the partnership's deemed liquidation resulting from
          the merger, Pioneer USA will pay an amount of Pioneer common stock and
          cash to the partners, other than itself, in accordance with the
          liquidation provisions of this Agreement. For purposes of Texas law,
          the merger shall be a merger subject to the provisions of Section 2.11
          of the Texas Revised Limited Partnership Act.

               4. Authority of Pioneer USA as General Partner. By obtaining the
          approval of the limited partners described in Section 2 of this
          Article, the partnership hereby extends the power of attorney granted
          to Pioneer USA pursuant to this Agreement to permit Pioneer USA to
          execute the merger agreement described in the Proxy
          Statement/Prospectus and the merger amendment contemplated by this
          Article on behalf of the limited partners. Pioneer USA shall be
          authorized, at such time in its full discretion as it deems
          appropriate, to execute, acknowledge, verify, deliver, file and
          record, for and in the name and on behalf of the partnership, Pioneer
          USA and the limited partners, any and all documents, agreements,
          certificates and instruments, and shall do and perform any and all
          acts required by applicable law or which Pioneer USA deems necessary
          or advisable in order to give effect to this Article and the
          transactions contemplated herein, including, but not limited to, the
          merger.


                                      D-2
   133

               5. This Article Controlling. The provisions of this Article shall
          control over all other provisions of this Agreement.

          Except as herein expressly amended, all other terms and provisions of
          this Agreement shall remain in full force and effect.


APPROVAL OF MERGER FOR EACH PARTNERSHIP FORMED IN DELAWARE:

     RESOLVED: That, subject to receipt of a favorable opinion of special legal
counsel for the limited partners as described in the proxy statement/prospectus,
the partnership be merged with and into Pioneer USA, with Pioneer USA being the
surviving entity, and that an amount in cash be paid to each partner, other than
Pioneer USA, in accordance with the terms set forth in the merger agreement
included as Appendix E to the proxy statement/prospectus and subject to the
conditions set forth therein.

     RESOLVED: That, subject to receipt of a favorable opinion of special legal
counsel for the limited partners as described in the proxy statement/prospectus,
the following new article shall be added to the partnership agreement of the
partnership:

                                     ARTICLE

               Notwithstanding any provisions of this Agreement to the contrary,
          it is hereby agreed as follows:

               1. Definitions. For the purposes of this Article, "Proxy
          Statement/Prospectus" means the proxy statement/prospectus dated     ,
          2001 of Pioneer Natural Resources Company, a Delaware corporation
          ("Pioneer"), and Pioneer Natural Resources USA, Inc., a Delaware
          corporation ("Pioneer USA"), contained in the Registration Statement
          on Form S-4 of Pioneer filed with the Securities and Exchange
          Commission.

               2. Elimination of Restrictions to Transaction. Notwithstanding
          anything in this Agreement to the contrary, upon the consent of
          limited partners holding a majority of the outstanding limited
          partnership interests in the partnership, which consent may or may not
          be the same consent to the adoption of an amendment to this Agreement,
          no provision of this Agreement shall prohibit, limit or prevent:

                    (a) the merger or consolidation of the partnership,
               including the merger described in the Proxy Statement/Prospectus,
               with any other domestic limited partnership or other business
               entity, as those terms are defined in the Delaware Revised
               Uniform Limited Partnership Act, and

                    (b) the consummation of the merger of the partnership as
               described in the Proxy Statement/Prospectus.

          In addition, no consent of the partnership, Pioneer USA or any partner
          or other procedure, including the delivery of opinions of counsel,
          shall be required in order to enable the partnership, Pioneer USA or
          any partner to effect the merger.

               3. Mergers. For purposes of this Agreement, each merger described
          in the Proxy Statement/Prospectus shall be treated as if the
          partnership has:

                    (a) disposed of all of its assets and liabilities to Pioneer
               USA in exchange for an amount in cash representing the merger
               value of the partnership, and

                    (b) liquidated in the manner provided in the liquidation
               provisions of this Agreement.

                                      D-3
   134

          Accordingly, upon the partnership's deemed liquidation resulting from
          the merger, Pioneer USA will pay an amount of Pioneer common stock and
          cash to the partners, other than itself, in accordance with the
          liquidation provisions of this Agreement. For purposes of Delaware
          law, the merger shall be a merger subject to the provisions of Section
          17.11 of the Delaware Revised Uniform Limited Partnership Act.

               4. Authority of Pioneer USA as General Partner. By obtaining the
          approval of the limited partners described in Section 2 of this
          Article, the partnership hereby extends the power of attorney granted
          to Pioneer USA pursuant to this Agreement to permit Pioneer USA to
          execute the merger agreement described in the Proxy
          Statement/Prospectus and the merger amendment contemplated by this
          Article on behalf of the limited partners. Pioneer USA shall be
          authorized, at such time in its full discretion as it deems
          appropriate, to execute, acknowledge, verify, deliver, file and
          record, for and in the name and on behalf of the partnership, Pioneer
          USA and the limited partners, any and all documents, agreements,
          certificates and instruments, and shall do and perform any and all
          acts required by applicable law or which Pioneer USA deems necessary
          or advisable in order to give effect to this Article and the
          transactions contemplated herein, including, but not limited to, the
          merger.

               5. This Article Controlling. The provisions of this Article shall
          control over all other provisions of this Agreement.

          Except as herein expressly amended, all other terms and provisions of
          this Agreement shall remain in full force and effect.

APPROVAL OF COUNSEL TO LIMITED PARTNERS FOR EACH PARTNERSHIP:

     RESOLVED: That the selection of _____________ of Dallas, Texas as special
legal counsel for the limited partners of the partnership for the purpose of
rendering the legal opinion described in the proxy statement/prospectus under
"The Merger of Each Partnership -- Legal Opinion for Limited Partners" be and
hereby is approved by Pioneer USA, on behalf of the partnership, and the limited
partners of such partnership.

     RESOLVED: That the legal opinion delivered pursuant to the partnership
agreement of the partnership as described in the proxy statement/prospectus
under "The Merger of Each Partnership -- Legal Opinion for Limited Partners," in
form and substance as set forth in Exhibit A to these merger proposals, be and
hereby is approved as in form and substance satisfactory to the limited partners
of such partnership in their reasonable judgment.


                                      D-4
   135


                                    EXHIBIT A

                                  TO APPENDIX D

                                       TO

                           PROXY STATEMENT/PROSPECTUS

                                   OPINION OF



Pioneer Natural Resources USA, Inc.,
As Sole or Managing General Partner of
46 Limited Partnerships Named in the
Proxy Statement/Prospectus dated             , 2001
1400 Williams Square West
5205 North O'Connor Blvd.
Irving, Texas 75039

     We are of the opinion that (1) neither the grant nor the exercise of the
right to approve the merger of each partnership with and into Pioneer Natural
Resources USA, Inc. by the partnership's limited partners will adversely affect
the federal income tax classification of the partnership or any of its limited
partners and (2) neither the grant nor exercise of such right will result in the
loss of any limited partner's limited liability.

     We hereby consent to the references to our firm and this opinion contained
in the proxy statement/prospectus forming a part of the registration statement
on Form S-4 originally filed with the Securities and Exchange Commission by
Pioneer Natural Resources Company, a Delaware corporation, on April 17, 2001 in
connection with the merger of each of the limited partnerships with and into
Pioneer Natural Resources USA, Inc., a Delaware corporation.



                                      D-5
   136

                                   APPENDIX E

                                       TO

                           PROXY STATEMENT/PROSPECTUS

                                     FORM OF

                          AGREEMENT AND PLAN OF MERGER
                           (DRILLING AND INCOME FUNDS)

         THIS AGREEMENT AND PLAN OF MERGER dated as of , 2001 (this "Merger
Agreement"), is entered into by and among Pioneer Natural Resources Company, a
Delaware corporation ("Pioneer"), Pioneer Natural Resources USA, Inc., a
Delaware corporation and wholly-owned subsidiary of Pioneer ("Pioneer USA"), and
each of the limited partnerships referred to below (each, a "Partnership" and
collectively, the "Partnerships").

                                    RECITALS

         A. Pioneer USA is the sole or managing general partner of each of the
following Partnerships:



                                                                     STATE OF
                       PARTNERSHIP NAME                             FORMATION
---------------------------------------------------------------  -----------------
                                                              
Parker & Parsley 81-I, Ltd.                                           Texas
Parker & Parsley 81-II, Ltd.                                          Texas
Parker & Parsley 82-I, Ltd.                                           Texas
Parker & Parsley 82-II, Ltd.                                          Texas
Parker & Parsley 82-III, Ltd.                                         Texas
Parker & Parsley 83-A, Ltd.                                           Texas
Parker & Parsley 83-B, Ltd.                                           Texas
Parker & Parsley 84-A, Ltd.                                           Texas
Parker & Parsley 85-A, Ltd.                                           Texas
Parker & Parsley 85-B, Ltd.                                           Texas
Parker & Parsley Private Investment 85-A, Ltd.                        Texas
Parker & Parsley Selected 85 Private Investment, Ltd.                 Texas
Parker & Parsley 86-A, Ltd.                                           Texas
Parker & Parsley 86-B, Ltd.                                           Texas
Parker & Parsley 86-C, Ltd.                                           Texas
Parker & Parsley Private Investment 86, Ltd.                          Texas
Parker & Parsley 87-A Conv., Ltd.                                     Texas
Parker & Parsley 87-A , Ltd.                                          Texas
Parker & Parsley 87-B Conv., Ltd.                                     Texas
Parker & Parsley 87-B, Ltd.                                           Texas
Parker & Parsley Producing Properties 87-A, Ltd.                      Texas
Parker & Parsley Producing Properties 87-B, Ltd.                      Texas
Parker & Parsley Private Investment 87, Ltd.                          Texas
Parker & Parsley 88-A Conv., L.P.                                    Delaware
Parker & Parsley 88-A, L.P.                                          Delaware
Parker & Parsley 88-B Conv., L.P.                                    Delaware
Parker & Parsley 88-B, L.P.                                          Delaware
Parker & Parsley 88-C Conv., L.P.                                    Delaware
Parker & Parsley 88-C, L.P.                                          Delaware
Parker & Parsley Producing Properties 88-A, L.P.                     Delaware
Parker & Parsley Private Investment 88, L.P.                         Delaware
Parker & Parsley 89-A Conv., L.P.                                    Delaware
Parker & Parsley 89-A, L.P.                                          Delaware
Parker & Parsley 89-B Conv., L.P.                                    Delaware
Parker & Parsley 89-B, L.P.                                          Delaware



                                      E-1
   137




                                                                     STATE OF
                       PARTNERSHIP NAME                             FORMATION
---------------------------------------------------------------  -----------------
                                                              
Parker & Parsley Private Investment 89, L.P.                         Delaware
Parker & Parsley 90-A Conv., L.P.                                    Delaware
Parker & Parsley 90-A, L.P.                                          Delaware
Parker & Parsley 90-B Conv., L.P.                                    Delaware
Parker & Parsley 90-B, L.P.                                          Delaware
Parker & Parsley 90-C Conv., L.P.                                    Delaware
Parker & Parsley 90-C, L.P.                                          Delaware
Parker & Parsley Private Investment 90, L.P.                         Delaware
Parker & Parsley 90 Spraberry Private Development, L.P.              Delaware
Parker & Parsley 91-A, L.P.                                          Delaware
Parker & Parsley 91-B, L.P.                                          Delaware


         B. Each of Parker & Parsley Employees 81-I, Ltd., a Texas limited
partnership, Parker & Parsley Employees 81-II, Ltd., a Texas limited
partnership, Parker & Parsley Employees 82-I, Ltd., a Texas limited partnership,
Parker & Parsley Employees 82-II, Ltd., a Texas limited partnership, Parker &
Parsley Employees 82-III, Ltd., a Texas limited partnership, Parker & Parsley
Employees 83-A, Ltd., a Texas limited partnership, Parker & Parsley Employees
83-B, Ltd., a Texas limited partnership, and Parker & Parsley Employees 84-A,
Ltd., a Texas limited partnership (individually, the "Nonmanaging General
Partner" and collectively, the "Nonmanaging General Partners"), is the
nonmanaging general partner of Parker & Parsley 81-I, Ltd., Parker & Parsley
81-II, Ltd., Parker & Parsley 82-I, Ltd., Parker & Parsley 82-II, Ltd., Parker &
Parsley 82-III, Ltd., Parker & Parsley 83-A, Ltd. Parker & Parsley 83-B, Ltd.
and Parker & Parsley 84-A, Ltd., respectively.

         C. Pioneer USA is the sole general partner of each of the Nonmanaging
General Partners and in such capacity has authority (i) to cause the Nonmanaging
General Partner to perform its obligations under the partnership agreement of
the respective Partnership; and (ii) to exercise on behalf of the Nonmanaging
General Partner all of the rights and elections granted to such Nonmanaging
General Partner by the respective Partnership.

         D. The board of directors of each of Pioneer and Pioneer USA has
determined that it is in the best interests of Pioneer and Pioneer USA (in its
individual capacity, as the sole or managing general partner of each Partnership
and as the sole general partner of each Nonmanaging General Partner) to merge
each Partnership with and into Pioneer USA and each such board of directors has
approved the merger of each Partnership referred to below, upon the terms and
subject to the conditions contained herein.

         E. Pioneer USA intends to solicit the vote of the limited partners of
each Partnership holding at least a majority (or with respect to Parker &
Parsley 91-A, L.P. and Parker & Parsley 91-B, L.P. (each, a "Super-Majority
Partnership"), at least 66?%) of the outstanding limited partnership interests
of the Partnership to approve the merger of the Partnership. Subject to certain
limitations, upon consummation of the merger of each Partnership, the partners,
other than Pioneer USA, will have the right to receive a number of shares of
common stock, par value $0.01 per share, of Pioneer (the "Pioneer Common Stock")
and an amount of cash.

                                   AGREEMENTS

         NOW, THEREFORE, in consideration of the premises and the mutual
agreements contained herein, the parties hereto agree as follows:

                                    ARTICLE 1
                         THE MERGER OF EACH PARTNERSHIP

         1.1 Merger of Each Partnership. At the Effective Time (as defined in
Section 1.4), each Partnership shall be merged with and into Pioneer USA, the
separate existence of the Partnership shall cease, and Pioneer USA, as the
surviving corporation, shall continue to exist by virtue of and shall be
governed by the laws of the State of Delaware.


                                      E-2
   138

         1.2 Merger Value for Each Partnership; Pioneer Common Stock and Cash
Offered.

                  (a) At the Effective Time, by virtue of the merger of each
Partnership and without any action on the part of Pioneer USA or the other
partners of the Partnership, each partnership interest outstanding immediately
prior thereto shall be converted into the right to receive a portion of the
amount of Pioneer Common Stock and cash allocated to the Partnership, which
portion shall be determined in accordance with the merger value assigned to the
Partnership pursuant to the procedures set forth herein and in the Proxy
Statement/Prospectus (as defined in Section 4.3) and the procedures set forth in
the Partnership's partnership agreement for allocating liquidation distributions
as though the assets of the Partnership were sold for the merger value of the
Partnership. The merger value for each Partnership is equal to the sum of the
present value of estimated future net revenues from the Partnership's oil and
gas reserves and its net working capital, in each case as of March 31, 2001 and
determined as described in the Proxy Statement/Prospectus. The merger value for
each Partnership will not be adjusted as of the Closing Date. The number of
shares of Pioneer Common Stock to be issued for each partnership interest of
each Partnership will be based on (i) 75% of the Partnership's merger value
divided by (ii) the average closing price of the Pioneer Common Stock, as
reported by the New York Stock Exchange, for the ten trading days ending three
business days before the date of the special meeting for the Partnership. The
remaining portion will be paid in cash. For purposes of illustration in the
Proxy Statement/Prospectus, Pioneer and Pioneer USA calculated the aggregate
number of shares of Pioneer Common Stock to be offered based on $18.00 per share
of Pioneer Common Stock. Pioneer and Pioneer USA shall update the aggregate
number of shares of Pioneer Common Stock to be issued based on the average
closing price as described in clause (ii) above before the date of the special
meeting for each Partnership. The merger value assigned to each Partnership and
the amount of Pioneer Common Stock and cash offered with respect to each $1,000
investment by the limited partners in the Partnership pursuant to the merger of
the Partnership are set forth in the table entitled "Summary Table - Merger
Value and Amount of Initial Limited Partner Investment Repaid" in the Proxy
Statement/Prospectus.

                  (b) All partnership interests of each Partnership, when
converted into the right to receive Pioneer Common Stock and cash, shall no
longer be outstanding and shall automatically be cancelled and retired and shall
cease to exist, and each holder of a certificate representing any such
partnership interests shall cease to have any rights with respect thereto,
except the right to receive the amount of Pioneer Common Stock and cash to be
delivered in consideration therefor.

                  (c) The partnership interests, whether general or limited, in
each Partnership held directly or indirectly by Pioneer USA shall be cancelled
without any consideration being received therefor; provided, however, that as a
result of the merger of each Partnership, Pioneer USA will own 100% of the
properties of the Partnership, including properties attributable to its
partnership interests in the Partnership.

                  (d) No fractional shares of Pioneer Common Stock will be
issued. Each fractional share of Pioneer Common Stock to be issued to a partner
of a Partnership will be rounded up to the nearest whole share. The cash payment
to that partner will be reduced by the value of the fractional share required to
complete a whole share multiplied by the price per share of Pioneer common stock
used to determine the number of shares to be issued.

                  (e) All cash payments shall be rounded to the nearest cent,
with .5 cent being rounded to one cent.

                  (f) When any person has partnership interests in more than one
Partnership that merges with Pioneer USA, Pioneer USA and Pioneer may, at their
sole discretion, aggregate the number of shares of Pioneer Common Stock or the
cash payments, or both, to that person before making the rounding and other
adjustments provided in the preceding clauses (d) and (e).

         1.3 Closing. The closing of the merger of each Partnership (the
"Closing") shall take place at the offices of Vinson & Elkins L.L.P., 3700
Trammell Crow Center, 2001 Ross Avenue, Dallas, Texas 75201, as soon as
practicable after the fulfillment of the conditions referred to in Article 4, or
at such other time and place as the parties shall agree (the date of such
Closing being the "Closing Date").

         1.4 Effective Time of Merger of Each Partnership. Upon satisfaction of
the conditions set forth in Article 4 hereof and as soon as practicable after
the Closing, this Merger Agreement, or a certificate of merger setting forth the
information required by, and otherwise in compliance with, Section 263 of the
General Corporation Law of the



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State of Delaware (the "DGCL") and, if applicable, Section 17-211 of the Revised
Uniform Limited Partnership Act of the State of Delaware (the "DRULPA") with
respect to the merger of each Partnership, shall be delivered for filing with
the Secretary of State of the State of Delaware. At such time, if applicable, a
certificate of merger with respect to the merger of each Partnership setting
forth the information required by, and otherwise in compliance with, Section
2.11 the Revised Limited Partnership Act of the State of Texas (the "TRLPA")
shall be delivered for filing with the Secretary of State of the State of Texas.
The merger of each Partnership shall become effective upon the later of (a) the
day and at the time the Secretary of State of the State of Delaware files this
Merger Agreement or such certificate of merger in compliance with Section 263 of
the DGCL and, if applicable, Section 17-211 of the DRULPA, and (b) if
applicable, the day and at the time the Secretary of State of the State of Texas
files such certificate of merger in compliance with Section 2.11 of the TRLPA
(the time of such effectiveness is herein called the "Effective Time").
Notwithstanding the foregoing, by action of its board of directors, either
Pioneer or Pioneer USA, in its individual capacity or as the sole general
partner of each Partnership, may terminate this Merger Agreement at any time
prior to the earlier of (a) the filing of this Merger Agreement or the
certificate of merger with respect to the merger of the Partnership in
compliance with Section 263 of the DGCL and, if applicable, Section 17-211 of
the DRULPA with the Secretary of State of the State of Delaware and (b) if
applicable, the filing of the certificate of merger with respect to the merger
of the Partnership in compliance with Section 2.11 of the TRLPA with Secretary
of State of the State of Texas.

         1.5 Effect of Merger of Each Partnership. At the Effective Time of the
merger of each Partnership, Pioneer USA, without further action, as provided by
the laws of the State of Delaware and the State of Texas, as the case may be,
shall succeed to and possess all the rights, privileges, powers, and franchises,
of a public as well as of a private nature, of the Partnership; and all
property, real, personal and mixed, and all debts due on whatsoever account,
including subscriptions to shares, and all other choses in action, and all and
every other interest, of or belonging to or due to the Partnership shall be
deemed to be vested in Pioneer USA without further act or deed; and the title to
any real estate, or any interest therein, vested in Pioneer USA or the
Partnership shall not revert or be in any way impaired by reason of the merger
of the Partnership. Such transfer to and vesting in Pioneer USA shall be deemed
to occur by operation of law, and no consent or approval of any other person
shall be required in connection with any such transfer or vesting unless such
consent or approval is specifically required in the event of merger or
consolidation by law or express provision in any contract, agreement, decree,
order, or other instrument to which Pioneer USA or the Partnership is a party or
by which either of them is bound. At and after the Effective Time, Pioneer USA
shall be responsible and liable for all debts, liabilities, and duties of each
Partnership, including franchise taxes, if any, which may be enforced against
Pioneer USA to the same extent as if said debts, liabilities, and duties had
been incurred or contracted by it. Neither the rights of creditors nor any liens
upon the property of any Partnership or Pioneer USA shall be impaired by the
merger of any Partnership.

         1.6 Certificate of Incorporation and Bylaws. The certificate of
incorporation of Pioneer USA before the merger of each Partnership shall be and
remain the certificate of incorporation of Pioneer USA after the Effective Time,
until the same shall thereafter be altered, amended, or repealed in accordance
with law and Pioneer USA's certificate of incorporation. The bylaws of Pioneer
USA as in effect at the Effective Time shall be and remain the bylaws of Pioneer
USA, as the surviving corporation, until the same shall thereafter be altered,
amended, or repealed in accordance with law, Pioneer USA's certificate of
incorporation or such bylaws.

         1.7 Pioneer USA Common Stock. At the Effective Time, each outstanding
share of common stock of Pioneer USA shall remain outstanding and shall continue
to represent one share of common stock of Pioneer USA.

         1.8 Officers and Directors. At the Effective Time, each of the persons
who was serving as an officer of Pioneer USA immediately prior to the Effective
Time shall continue to be an officer of Pioneer USA and shall continue to serve
in such capacity at the pleasure of the board of directors of Pioneer USA or, if
earlier, until their respective death or resignation. At the Effective Time,
each of the persons who was serving as a director of Pioneer USA immediately
prior to the Effective Time shall continue to be a director of Pioneer USA, and
each shall serve in such capacity until the next annual meeting of stockholders
of Pioneer USA and until his or her successor is elected and qualified or, if
earlier, until his death, resignation, or removal from office.

         1.9 Exchange of Partnership Interests for Pioneer Common Stock and
Cash.

                  (a) Pioneer USA shall mail certificates representing shares of
Pioneer Common Stock and checks to the partners of record, other than Pioneer
USA, of each Partnership promptly following the Closing Date in


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payment of the merger consideration. Limited partners and Nonmanaging General
Partners of each Partnership will not be required to surrender partnership
interest certificates to receive the Pioneer Common Stock and the cash payment.

                  (b) After the Closing Date, there shall not be any further
registration of transfers on the transfer books of any Partnership of the
partnership interests that were issued and outstanding immediately before the
Closing Date and were converted into the right to receive Pioneer Common Stock
and cash. If, after the Closing Date, certificates representing partnership
interests of a Partnership are presented, they shall be exchanged for Pioneer
Common Stock and cash, all as provided in this Article.

                                    ARTICLE 2
                         REPRESENTATIONS AND WARRANTIES

         2.1 Representations and Warranties of Each Partnership. Each
Partnership hereby represents and warrants to Pioneer and Pioneer USA as
follows:

                  (a) Formation; Qualification. The Partnership is a limited
partnership duly formed under the DRULPA or TRLPA, as applicable, and is validly
existing and in good standing under the laws of the State of Delaware or the
State of Texas, as applicable. The Partnership has all requisite partnership
power and authority to own, operate or lease its properties and to carry on its
business as now being conducted. The Partnership is duly qualified to do
business as a foreign limited partnership and is in good standing in each
jurisdiction where the character of its properties owned, operated or leased, or
the nature of its activities, makes such qualifications necessary.

                  (b) Capitalization. All of the outstanding partnership
interests of the Partnership are free of all liens, encumbrances, defects and
preemptive rights and are fully paid. Except as described in the Proxy
Statement/Prospectus, there are no outstanding subscriptions, options or other
arrangements or commitments obligating the Partnership to issue any additional
partnership interests.

                  (c) No Conflicts. Assuming this Merger Agreement is approved
by the requisite vote of the limited partners of the Partnership (with respect
to Parker & Parsley 85-A, Ltd., Parker & Parsley 85-B, Ltd., Parker & Parsley
Private Investment 85-A, Ltd., Parker & Parsley Selected 85 Private Investment,
Ltd., Parker & Parsley Private Investment 86, Ltd., Parker & Parsley 91-A, L.P.
and Parker & Parsley 91-B, L.P. (each, a "Special Vote Partnership"), excluding
Pioneer USA and its affiliates), consummation of the transactions contemplated
hereby and compliance with the terms and provisions of this Merger Agreement
will not conflict with, result in a breach of, require notice under or
constitute a default under (i) its certificate of limited partnership or
partnership agreement, (ii) any material judgment, order, injunction, decree or
ruling of any court or governmental authority or (iii) any material agreement,
indenture or instrument to which the Partnership is a party.

                  (d) Authority, Authorization and Enforceability. The
Partnership has all requisite power and authority to enter into and perform the
provisions of this Merger Agreement. The execution and delivery of this Merger
Agreement and the consummation of the transactions contemplated hereby have been
duly authorized by all necessary partnership action on the part of the
Partnership other than the approval of its limited partners (with respect to
each Special Vote Partnership, excluding Pioneer USA and its affiliates).
Subject to such approval, this Merger Agreement has been duly executed and
delivered by the Partnership and constitutes a valid and binding obligation of
the Partnership enforceable in accordance with its terms.

                  (e) SEC Reports; Financial Statements.

                           (i) With respect to each of Reporting Partnership (as
         defined below), the Partnership's (A) Annual Report on Form 10-K for
         the year ended December 31, 2000, (B) Quarterly Report on Form 10-Q for
         the quarter ended March 31, 2001, and (C) all other reports or
         registration statements filed with the Securities and Exchange
         Commission (the "SEC") since December 31, 2000 (collectively, the
         "Partnership's SEC Reports") (1) were prepared in accordance with the
         applicable requirements of the Securities Act of 1933 (the "Securities
         Act") and the Securities Exchange Act of 1934 (the "Exchange Act"), and
         (2) as of their respective dates, did not contain any untrue statement
         of a material fact or omit to


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         state a material fact required to be stated therein or necessary in
         order to make the statements therein, in the light of the circumstances
         under which they are made, not misleading.

                           (ii) Each of the financial statements of the
         Partnership for the year ended December 31, 2000 and for the three
         months ended March 31, 2001 contained in the Partnership's supplement
         to the Proxy Statement/Prospectus and, with respect to each Reporting
         Partnership, in the Partnership's SEC Reports has been prepared in
         accordance with generally accepted accounting principles applied on a
         consistent basis throughout the periods involved (except as may be
         indicated in the notes thereto) and each fairly presents the financial
         position of the Partnership as of the respective dates thereof and the
         results of operations and cash flows of the Partnership for the periods
         indicated, except that the unaudited interim financial statements are
         subject to normal and recurring year-end adjustments that are not
         expected to be material in amount.

                           (iii) For purposes hereof, the term "Reporting
         Partnership" means: Parker & Parsley 82-I, Ltd., Parker & Parsley
         82-II, Ltd., Parker & Parsley 83-A, Ltd., Parker & Parsley 83-B, Ltd.,
         Parker & Parsley 84-A, Ltd., Parker & Parsley 85-A, Ltd., Parker &
         Parsley 85-B, Ltd., Parker & Parsley 86-A, Ltd., Parker & Parsley 86-B,
         Ltd., Parker & Parsley 86-C, Ltd., Parker & Parsley 87-A, Ltd., Parker
         & Parsley 87-B, Ltd., Parker & Parsley Producing Properties 87-A, Ltd.,
         Parker & Parsley Producing Properties 87-B, Ltd., Parker & Parsley
         88-A, L.P., Parker & Parsley 88-B, L.P., Parker & Parsley Producing
         Properties 88-A, L.P., Parker & Parsley 89-A, L.P., Parker & Parsley
         90-A L.P., Parker & Parsley 90-B Conv., L.P., Parker & Parsley 90-B,
         L.P., Parker & Parsley 90-C Conv., L.P., Parker & Parsley 90-C, L.P.,
         Parker & Parsley 91-A, L.P. and Parker & Parsley 91-B, L.P.

                  (f) No Material Adverse Change. Since March 31, 2001, the
Partnership has conducted its operations in the ordinary and usual course of
business and has paid all of its obligations as they have become due; and the
business of the Partnership has not undergone any material adverse change since
such date.

                  (g) Accuracy of Information. None of the information supplied
or to be supplied by the Partnership for inclusion in the Proxy
Statement/Prospectus, as amended or supplemented, will, at the time of the
mailing of the Proxy Statement/Prospectus, the time of the special meeting of
the limited partners of the Partnership (each, a "Special Meeting") or the
Closing Date, be false or misleading with respect to any material fact, contain
any untrue statement of material fact or omit to state any material fact
required to be stated therein or necessary in order to make the statements
therein, in the light of the circumstances under which they were made, not
misleading.

         2.2 Representations and Warranties of Pioneer USA. Pioneer USA hereby
represents and warrants to Pioneer and each Partnership as follows:

                  (a) Organization; Qualification. Pioneer USA is a corporation
duly formed under the DGCL and is validly existing and in good standing under
the laws of the State of Delaware. Pioneer USA has all requisite corporate power
and authority to own, operate or lease its properties and to carry on its
business as now being conducted. Pioneer USA is duly qualified to do business as
a foreign corporation and is in good standing in each jurisdiction where the
character of its properties owned, operated or leased, or the nature of its
activities, makes such qualifications necessary.

                  (b) No Conflicts. Consummation of the transactions
contemplated hereby and compliance with the terms and provisions of this Merger
Agreement will not conflict with, result in a breach of, require notice under or
constitute a default under (i) its certificate of incorporation or bylaws, (ii)
any material judgment, order, injunction, decree or ruling of any court or
governmental authority or (iii) any material agreement, indenture or instrument
to which Pioneer USA is a party.

                  (c) Authority, Authorization and Enforceability. Pioneer USA
has all requisite corporate power and authority to execute and deliver this
Merger Agreement and to perform the provisions of this Merger Agreement. The
execution and delivery of this Merger Agreement and the consummation of the
transactions contemplated hereby have been duly authorized by all necessary
corporate action on the part of Pioneer USA. This Merger Agreement has been duly
executed and delivered by Pioneer USA and constitutes a valid and binding
obligation of Pioneer USA enforceable in accordance with its terms.


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                  (d) No Material Adverse Change. Since March 31, 2001, Pioneer
USA has conducted its operations in the ordinary and usual course of business
and has paid all of its obligations as they have become due; and the business of
Pioneer USA has not undergone any material adverse change since such date.

                  (e) Accuracy of Information. None of the information supplied
or to be supplied by Pioneer USA for inclusion in the Proxy
Statement/Prospectus, as amended or supplemented, will, at the time of the
mailing of the Proxy Statement/Prospectus, the time of the Special Meeting of
each Partnership or the Closing Date, be false or misleading with respect to any
material fact, contain any untrue statement of material fact or omit to state
any material fact required to be stated therein or necessary in order to make
the statements therein, in the light of the circumstances under which they were
made, not misleading.

                  (f) Capacity as General Partner. Pioneer USA is the sole or
managing general partner of each Partnership and is the sole general partner of
each Nonmanaging General Partner.

         2.3 Representations and Warranties of Pioneer. Pioneer hereby
represents and warrants to Pioneer USA and each Partnership as follows:

                  (a) Organization; Qualification. Pioneer is a corporation duly
formed under the DGCL and is validly existing and in good standing under the
laws of the State of Delaware. Pioneer has all requisite corporate power and
authority to own, operate or lease its properties and to carry on its business
as now being conducted. Pioneer is duly qualified to do business as a foreign
corporation and is in good standing in each jurisdiction where the character of
its properties owned, operated or leased, or the nature of its activities, makes
such qualifications necessary.

                  (b) No Conflicts. Consummation of the transactions
contemplated hereby and compliance with the terms and provisions of this Merger
Agreement will not conflict with, result in a breach of, require notice under or
constitute a default under (i) its certificate of incorporation or bylaws, (ii)
any material judgment, order, injunction, decree or ruling of any court or
governmental authority or (iii) any material agreement, indenture or instrument
to which Pioneer is a party.

                  (c) Authority, Authorization and Enforceability. Pioneer has
all requisite corporate power and authority to execute and deliver this Merger
Agreement and to perform the provisions of this Merger Agreement. The execution
and delivery of this Merger Agreement and the consummation of the transactions
contemplated hereby have been duly authorized by all necessary corporate action
on the part of Pioneer. This Merger Agreement has been duly executed and
delivered by Pioneer and constitutes a valid and binding obligation of Pioneer
enforceable in accordance with its terms. When issued in accordance with this
Merger Agreement, the shares of Pioneer Common Stock will be validly issued,
fully paid and nonassessable and not subject to preemptive rights.

                  (d) SEC Reports; Financial Statements.

                           (i) Pioneer's (A) Annual Report on Form 10-K for the
         year ended December 31, 2000, (B) Quarterly Report on Form 10-Q for the
         quarter ended March 31, 2001, and (C) all other reports or registration
         statements filed with the SEC since December 31, 2000 (collectively,
         "Pioneer's SEC Reports") (1) were prepared in accordance with the
         applicable requirements of the Securities Act and the Exchange Act, and
         (2) as of their respective dates, did not contain any untrue statement
         of a material fact or omit to state a material fact required to be
         stated therein or necessary in order to make the statements therein, in
         the light of the circumstances under which they are made, not
         misleading.

                           (ii) Each of the financial statements of Pioneer for
         the year ended December 31, 2000 and for the three months ended March
         31, 2001 contained in Pioneer's SEC Reports has been prepared in
         accordance with generally accepted accounting principles applied on a
         consistent basis throughout the periods involved (except as may be
         indicated in the notes thereto) and each fairly presents the financial
         position of Pioneer as of the respective dates thereof and the results
         of operations and cash flows of Pioneer for the periods indicated,
         except that the unaudited interim financial statements are subject to
         normal and recurring year-end adjustments that are not expected to be
         material in amount.


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                  (e) No Material Adverse Change. Since March 31, 2001, Pioneer
has conducted its operations in the ordinary and usual course of business and
has paid all of its obligations as they have become due; and the business of
Pioneer has not undergone any material adverse change since such date.

                  (f) Accuracy of Information. None of the information supplied
or to be supplied by Pioneer for inclusion in the Proxy Statement/Prospectus, as
amended or supplemented, will, at the time of the mailing of the Proxy
Statement/Prospectus, the time of the Special Meeting of each Partnership or the
Closing Date, be false or misleading with respect to any material fact, contain
any untrue statement of material fact or omit to state any material fact
required to be stated therein or necessary in order to make the statements
therein, in the light of the circumstances under which they were made, not
misleading.

                                    ARTICLE 3
             CONDITIONS PRECEDENT TO THE MERGER OF EACH PARTNERSHIP

         3.1 Conditions to Each Party's Obligations to Effect the Merger of Each
Partnership. The respective obligations of each party to effect the merger of
each Partnership shall be subject to the fulfillment (or waiver in whole or in
part by the intended beneficiary thereof in its sole discretion) at or prior to
the Closing Date of the following conditions:

                  (a) This Merger Agreement, an amendment to the partnership
agreement of each Partnership to permit the merger of such Partnership (the
"Merger Amendment"), the selection of special counsel for the limited partners
and that counsel's legal opinion referred to in Section 3.1(c) shall have been
approved by the limited partners (with respect to each Special Vote Partnership,
excluding Pioneer USA and its affiliates) holding at least a majority (or, with
respect to each Super-Majority Partnership, at least 66?%) of the outstanding
limited partnership interests voting in person or by proxy at the Special
Meetings at which a quorum is present, with respect to each merger.

                  (b) Pioneer USA shall have received from Robert A. Stanger &
Co., Inc. a written opinion for inclusion in the Proxy Statement/Prospectus
satisfactory in form and substance to Pioneer USA and substantially to the
effect that, as of the date of that opinion, the merger value for each
Partnership and the allocation of the merger value of the Partnership (1) to the
limited partners of the Partnership as a group, (2) to the general partners of
the Partnership as a group, (3) to Pioneer USA as the managing or sole general
partner of the Partnership, (4) to the unaffiliated limited partners of the
Partnership as a group and (5) to the unaffiliated limited partners of the
Nonmanaging General Partner, if any, of the Partnership as a group, is fair to
the unaffiliated limited partners of the Partnership and the unaffiliated
limited partners of the Nonmanaging General Partner, if any, of the Partnership,
from a financial point of view. Such opinion shall not have been withdrawn prior
to the Closing Date, unless a replacement opinion or opinions of an investment
banking firm or firms satisfactory to Pioneer USA to a similar effect has been
received by Pioneer USA and has not been withdrawn.

                  (c) The receipt, on or prior to the Closing Date, by Pioneer
USA of the opinion of special legal counsel for the limited partners pursuant to
the partnership agreement of each Partnership.

                  (d) No provision of any applicable law or regulation and no
judgment, injunction, order or decree shall prohibit the consummation of the
merger of any Partnership and the transactions related thereto.

                  (e) No suit, action or proceeding shall have been filed or
otherwise be pending against Pioneer, Pioneer USA or any officer, director or
affiliate of Pioneer or Pioneer USA challenging the legality or any aspect of
the merger of any Partnership or the transactions related thereto.

                  (f) The shares of Pioneer Common Stock issuable upon the
merger of each Partnership pursuant to this Merger Agreement shall have been
authorized for listing on the New York Stock Exchange and the Toronto Stock
Exchange upon official notice of issuance.

                  (g) The parties to the merger of each Partnership having made
all filings and registrations with, and notifications to, all third parties,
including, without limitation, lenders and all appropriate regulatory
authorities, required for consummation of the transactions contemplated by this
Merger Agreement (other than the filing and recordation of appropriate merger
documents required by the DGCL, the DRULPA and the TRLPA, as applicable),



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and all approvals and authorizations and consents of all third parties,
including, without limitation, lenders and all regulatory authorities, required
for consummation of the transactions contemplated by this Merger Agreement shall
have been received and shall be in full force and effect, except for such
filings, registrations, notifications, approvals, authorizations and consents,
the failure of which to make or obtain would not have a material adverse effect
on the business or financial condition of Pioneer, Pioneer USA or any
Partnership.

                  (h) The absence of any opinion of counsel that the exercise by
the limited partners of any Partnership of the right to approve the merger of
such Partnership is not permitted under applicable state law.

         3.2 Conditions to Obligations of Pioneer to Effect the Merger of Each
Partnership. The obligations of Pioneer to effect the merger of each Partnership
shall be subject to the fulfillment (or waiver in whole or in part by the
intended beneficiary thereof in its sole discretion), at or prior to the Closing
Date, of the following additional conditions:

                  (a) Pioneer USA and each Partnership shall have performed in
all material respects their respective agreements contained in this Merger
Agreement required to be performed at or prior to the Closing Date.

                  (b) The representations and warranties of Pioneer USA and each
Partnership contained in this Merger Agreement shall be true and correct in all
material respects at and as of the Closing Date as if made at and as of such
time unless they relate to another specified time.

         3.3 Conditions to Obligations of Pioneer USA and Each Partnership to
Effect the Merger of Such Partnership. The obligations of Pioneer USA and each
Partnership to effect the merger of such Partnership shall be subject to the
fulfillment (or waiver in whole or in part by the intended beneficiary thereof
in its sole discretion) at or prior to the Closing Date of the following
additional conditions:

                  (a) Pioneer shall have performed in all material respects its
agreements contained in this Merger Agreement required to be performed at or
prior to the Closing Date.

                  (b) The representations and warranties of Pioneer contained in
this Merger Agreement shall be true and correct in all material respects at and
as of the Closing Date as if made at and as of such time unless they relate to
another specific time.

                                    ARTICLE 4
                              ADDITIONAL AGREEMENTS

         4.1 Conduct of Business Pending the Merger of Each Partnership. Each
Partnership covenants and agrees that, between the date of this Merger Agreement
and the Closing Date, unless the other parties shall otherwise agree in writing
or as otherwise contemplated in this Merger Agreement, it shall conduct its
businesses only in the ordinary course of business and in a manner consistent
with past practice, and it shall not take any action except for actions
consistent with such practice. Each Partnership shall use its reasonable best
efforts to preserve intact its business organization, to keep available the
services of its present officers, employees and consultants, and to preserve its
relationships with customers, suppliers and other persons with which it has
significant business dealings.

         4.2 Special Meetings; Proxies. As soon as reasonably practicable after
the execution of this Merger Agreement, Pioneer USA will take all action
necessary to duly call, give notice of, convene and hold the Special Meetings to
consider and vote upon approval of this Merger Agreement, the Merger Amendment,
the selection of special legal counsel for the limited partners, that counsel's
legal opinion referred to in Section 3.1(c) and the transactions contemplated
hereby and thereby. Pioneer USA will use its reasonable best efforts to solicit
from the limited partners proxies in favor of this Merger Agreement, the Merger
Amendment, the selection of special legal counsel for the limited partners, that
counsel's legal opinion referred to in Section 3.1(c) and the transactions
contemplated hereby and thereby, and to take all other action necessary or
advisable to secure any vote or consent of the limited partners of each
Partnership required by the partnership agreement of the Partnership or this
Merger Agreement or applicable law to effect the merger of the Partnership.

         4.3 Proxy Statement/Prospectus. Pioneer and Pioneer USA shall file with
the SEC under the Exchange Act a preliminary proxy statement/prospectus for each
Special Meeting (the definitive form of such proxy



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statement/prospectus is referred to as the "Proxy Statement/Prospectus").
Pioneer and Pioneer USA shall use all reasonable commercial efforts to have the
Proxy Statement/Prospectus cleared with the SEC as promptly as practicable.
Pioneer and Pioneer USA shall cause the Proxy Statement/Prospectus to be mailed
to the limited partners of each Partnership as soon as practicable in accordance
with applicable federal and state law.

         4.4 Authorization for Shares and Stock Exchange Listing. Prior to the
Effective Time, Pioneer and Pioneer USA shall have taken all action necessary to
permit Pioneer to issue the number of shares of Pioneer Common Stock required to
be issued pursuant to this Merger Agreement. Each of Pioneer and Pioneer USA
shall use its commercially reasonable efforts to cause the shares of Pioneer
Common Stock to be issued in the merger of each Partnership to be approved for
listing on the New York Stock Exchange and the Toronto Stock Exchange, subject
to official notice of issuance, prior to the Closing Date.

         4.5 Additional Agreements. Subject to the terms and conditions herein
provided, each of the parties hereto agrees to use all reasonable commercial
efforts to obtain in a timely manner all necessary waivers, consents and
approvals and to effect all necessary registrations and filings, and to use all
reasonable commercial efforts to take, or cause to be taken, all other actions
and to do, or cause to be done, all other things necessary, proper or advisable
under applicable laws and regulations to consummate and make effective as
promptly as practicable the transactions contemplated by this Merger Agreement.

                                    ARTICLE 5
                                   TERMINATION

         5.1 Termination. This Merger Agreement may be terminated and the merger
of any Partnership contemplated hereby may be abandoned, in whole or in part, at
any time prior to the Effective Time, whether before or after approval of the
merger of the Partnership by its limited partners (with respect to each Special
Vote Partnership, excluding Pioneer USA and its affiliates):

                  (a) By mutual written consent of the parties;

                  (b) By any party, if:

                           (i) there shall be any applicable law, rule or
         regulation that makes consummation of the merger of any Partnership
         illegal or otherwise prohibited or if any judgment, injunction, order
         or decree enjoining any party from consummating the merger of any
         Partnership is entered and such judgment, injunction, order or decree
         shall have become final and non-appealable;

                           (ii) at the Special Meeting of each Partnership or at
         any adjournment or postponement thereof, the approval of the limited
         partners of the Partnership referred to in Section 3.1(a) shall not
         have been obtained by reason of the failure to obtain the requisite
         vote; or

                           (iii) there shall be any pending suit, action or
         proceeding filed against Pioneer, Pioneer USA, any Partnership or any
         officer, director or affiliate of Pioneer or Pioneer USA challenging
         the legality or any aspect of the merger of any Partnership or the
         transactions related thereto;

                  (c) By Pioneer, if either Pioneer USA or any Partnership shall
have failed to perform its agreements and covenants contained herein, which
failure has a material adverse effect on Pioneer USA or such Partnership, as the
case may be, or materially and adversely affects the transactions contemplated
by this Merger Agreement;

                  (d) By Pioneer USA or any Partnership with respect to the
Partnership's merger, if Pioneer shall have failed to perform its agreements and
covenants contained herein, which failure has a material adverse effect on
Pioneer USA or such Partnership, as the case may be, or materially and adversely
affects the transactions contemplated by this Merger Agreement;

                  (e) By Pioneer or Pioneer USA, pursuant to Section 1.4 hereof;


                                      E-10
   146

                  (f) By Pioneer USA, if Pioneer USA, after considering the
written advice of outside legal counsel, determines in good faith that
termination of this Merger Agreement is required for Pioneer USA's board of
directors to comply with its fiduciary duties to its sole stockholder or to any
Partnership imposed by applicable law; or

                  (g) By Pioneer, if there shall have occurred any event,
circumstance, condition, development or occurrence causing, resulting in or
having, or reasonably expected to cause, result in or have, a material adverse
effect (i) on any Partnership's business, operations, properties (taken as a
whole), condition (financial or otherwise), results of operations, assets (taken
as a whole), liabilities, cash flows or prospects, (ii) on market prices for oil
and gas prevailing generally in the oil and gas industry since the date of
determination of the oil and gas commodity prices used in the determination of
the merger value for each Partnership, (iii) on the price of Pioneer Common
Stock or (iv) on the oil and gas industry generally.

         5.2 Effect of Termination. In the event of termination of this Merger
Agreement by a party as provided in Section 5.1, written notice thereof shall
promptly be given to the other parties and this Merger Agreement shall forthwith
terminate without further action by any of the parties hereto. If this Merger
Agreement is terminated as so provided, there shall be no liabilities or
obligations hereunder on the part of any party hereto except as provided in
Section 6.13 and except that nothing herein shall relieve any party hereto from
liability for any breach of this Merger Agreement.

                                    ARTICLE 6
                                  MISCELLANEOUS

         6.1 Headings. The headings contained in this Merger Agreement are for
reference purposes only and shall not affect in any way the meaning or
interpretation of this Merger Agreement.

         6.2 Amendment. This Merger Agreement may be supplemented, amended or
modified by an instrument in writing signed by Pioneer and Pioneer USA (on
behalf of itself and as (a) the sole or managing general partner of each
Partnership, (b) the sole general partner of each Nonmanaging General Partner
and (c) attorney-in-fact for the limited partners of each Partnership) at any
time prior to the Closing Date; provided, however, that after approval by the
limited partners of each Partnership (with respect to each Special Vote
Partnership, excluding Pioneer USA and its affiliates) of this Merger Agreement,
the Merger Amendment, the selection of special legal counsel for the limited
partners and that counsel's legal opinion referred to in Section 3.1(c), no
amendment may be made which would adversely change the type or amount of, or the
method for determining, the consideration to be received upon consummation of
the merger of each Partnership or which would in any other way materially and
adversely affect the rights of such limited partners (other than a termination
of this Merger Agreement or abandonment of the merger of any Partnership).

         6.3 Waiver. At any time prior to the Closing Date, the parties hereto
may (a) extend the time for the performance of any of the obligations or other
acts of the other parties hereto, (b) waive any inaccuracies in the
representations and warranties contained herein or in any document delivered
pursuant hereto, and (c) waive compliance with any of the agreements or
conditions contained herein. Any such extension or waiver shall not operate as
an extension or waiver of, or estoppel with respect to, any subsequent failure
of compliance or other failure. Any agreement on the part of a party hereto to
any such extension or waiver shall be valid against such party if set forth in
an instrument in writing signed by such party.

         6.4 Expiration of Representations and Warranties. All representations
and warranties made pursuant to this Merger Agreement shall expire with, and be
terminated and extinguished by, the merger of each Partnership on the Closing
Date.

         6.5 Notices. All notices and other communications to be given or made
hereunder by any party shall be delivered by first class mail, or by personal
delivery, postage or fees prepaid, (a) to Pioneer at 1400 Williams Square West,
5205 North O'Connor Boulevard, Irving, Texas 75039, Attn: Scott D. Sheffield,
with a copy to Vinson & Elkins L.L.P., 3700 Trammell Crow Center, 2001 Ross
Avenue, Dallas, Texas 75201, Attn: Robert L. Kimball, and (b) to the other
parties at Pioneer Natural Resources USA, Inc., 1400 Williams Square West, 5205
North O'Connor Boulevard, Irving, Texas 75039, Attn: Mark L. Withrow, with a
copy to Sayles, Lidji & Werbner, 4400 Renaissance Tower, 1201 Elm Street,
Dallas, Texas 75270, Attn: Brian M. Lidji.


                                      E-11
   147

         6.6 Counterparts. This Merger Agreement may be executed in one or more
counterparts, each of which shall be deemed an original, but all of which
together shall constitute one and the same agreement.

         6.7 Severability. If any term or other provision of this Merger
Agreement is invalid, illegal or incapable of being enforced by any rule of law
or public policy, all other conditions and provisions of this Merger Agreement
shall nevertheless remain in full force and effect so long as the economic or
legal substance of the transactions contemplated hereby is not affected in any
manner materially adverse to any party.

         6.8 Entire Agreement. This Merger Agreement, including the documents
and instruments referred to herein, constitutes the entire agreement and
supersedes all other prior agreements and undertakings, both written and oral,
between the parties, or any of them, with respect to the subject matter hereof.

         6.9 Remedies. Except as otherwise expressly provided herein, this
Merger Agreement is not intended to confer upon any other person any rights or
remedies hereunder.

         6.10 Assignment. This Merger Agreement shall not be assigned by
operation of law or otherwise without the consent of all parties hereto.

         6.11 No Implied Waiver. Except as expressly provided in this Merger
Agreement, no course of dealing among the parties hereto and no delay by any of
them in exercising any right, power or remedy conferred herein or now or
hereafter existing at law or in equity, by statute or otherwise, shall operate
as a waiver of, or otherwise prejudice, any such right, power or remedy.

         6.12 Governing Law. Except to the extent that TRLPA is mandatorily
applicable, this Merger Agreement shall be governed by, and construed in
accordance with, the laws of the State of Delaware (regardless of the laws that
might otherwise govern under applicable principles of conflicts of law) as to
all matters.

         6.13 Expenses. Except as otherwise provided herein, Pioneer shall pay
all costs and expenses incurred in connection with this Merger Agreement and the
transactions contemplated hereby, whether or not the merger of each Partnership
is completed.

         6.14 Liquidation. Each Partnership, Pioneer and Pioneer USA intend and
agree that the merger of each Partnership shall be treated as a liquidation of
the Partnership into Pioneer USA pursuant to Section 332 of the Internal Revenue
Code of 1986, as amended, and shall make all declarations and filings necessary
to accomplish such intent and liquidation.

                            [Signature pages follow.]


                                      E-12
   148


         IN WITNESS WHEREOF, each of the parties hereto has executed this Merger
Agreement as of the date first written above.

                                PIONEER NATURAL RESOURCES COMPANY


                                By:
                                   ----------------------------------
                                Name:
                                      -------------------------------
                                Title:
                                      -------------------------------


                                PIONEER NATURAL RESOURCES USA, INC.


                                By:
                                   ----------------------------------
                                   Mark L. Withrow
                                   Executive Vice President, General
                                   Counsel and Secretary


                                PARTNERSHIPS:

                                Parker & Parsley 81-I, Ltd.
                                Parker & Parsley 81-II, Ltd.
                                Parker & Parsley 82-I, Ltd.
                                Parker & Parsley 82-II, Ltd.
                                Parker & Parsley 82-III, Ltd.
                                Parker & Parsley 83-A, Ltd.
                                Parker & Parsley 83-B, Ltd.
                                Parker & Parsley 84-A, Ltd.
                                Parker & Parsley 85-A, Ltd.
                                Parker & Parsley 85-B, Ltd.
                                Parker & Parsley Private Investment 85-A, Ltd.
                                Parker & Parsley Selected 85 Private Investment,
                                  Ltd.
                                Parker & Parsley 86-A, Ltd.
                                Parker & Parsley 86-B, Ltd.
                                Parker & Parsley 86-C, Ltd.
                                Parker & Parsley Private Investment 86, Ltd.
                                Parker & Parsley 87-A Conv., Ltd.
                                Parker & Parsley 87-A , Ltd.
                                Parker & Parsley 87-B Conv., Ltd.
                                Parker & Parsley 87-B, Ltd.
                                Parker & Parsley Producing Properties 87-A, Ltd.
                                Parker & Parsley Producing Properties 87-B, Ltd.
                                Parker & Parsley Private Investment 87, Ltd.
                                Parker & Parsley 88-A Conv., L.P.
                                Parker & Parsley 88-A, L.P.
                                Parker & Parsley 88-B Conv., L.P.
                                Parker & Parsley 88-B, L.P.
                                Parker & Parsley 88-C Conv., L.P.
                                Parker & Parsley 88-C, L.P.
                                Parker & Parsley Producing Properties 88-A, L.P.
                                Parker & Parsley Private Investment 88, L.P.
                                Parker & Parsley 89-A Conv., L.P.
                                Parker & Parsley 89-A, L.P.
                                Parker & Parsley 89-B Conv., L.P.
                                Parker & Parsley 89-B, L.P.
                                Parker & Parsley Private Investment 89, L.P.


                                      E-13

   149

                                Parker & Parsley 90-A Conv., L.P.
                                Parker & Parsley 90-A, L.P.
                                Parker & Parsley 90-B Conv., L.P.
                                Parker & Parsley 90-B, L.P.
                                Parker & Parsley 90-C Conv., L.P.
                                Parker & Parsley 90-C, L.P.
                                Parker & Parsley Private Investment 90, L.P.
                                Parker & Parsley 90 Spraberry Private
                                  Development, L.P.
                                Parker & Parsley 91-A, L.P.
                                Parker & Parsley 91-B, L.P.

                                By: Pioneer Natural Resources USA, Inc., as the
                                    sole or managing general partner of each
                                    Partnership


                                By:
                                    --------------------------------------------
                                    Mark L. Withrow
                                    Executive Vice President, General Counsel
                                    and Secretary


                                By: Pioneer Natural Resources USA, Inc., as the
                                    sole general partner of each Nonmanaging
                                    General Partner


                                By:
                                   --------------------------------------------
                                   Mark L. Withrow
                                   Executive Vice President, General Counsel and
                                   Secretary


                                By:  Pioneer Natural Resources USA, Inc., as
                                     attorney-in-fact for the limited partners
                                     of each Partnership


                                By:
                                   --------------------------------------------
                                   Mark L. Withrow
                                   Executive Vice President, General Counsel and
                                   Secretary


                                      E-14

   150
                        PIONEER NATURAL RESOURCES COMPANY
                       PIONEER NATURAL RESOURCES USA, INC.
                            1400 WILLIAMS SQUARE WEST
                            5205 NORTH O'CONNOR BLVD.
                               IRVING, TEXAS 75039

                            SUPPLEMENTAL INFORMATION

                                       OF

            PARKER & PARSLEY 81-I, LTD., A TEXAS LIMITED PARTNERSHIP

                                       TO

                  PROXY STATEMENT/PROSPECTUS DATED      , 2001

                                   ----------

                   THE DATE OF THIS SUPPLEMENT IS      , 2001

                                   ----------

     This document contains important information specific to Parker & Parsley
81-I, Ltd. and supplements the proxy statement/prospectus dated      , 2001, of
Pioneer Natural Resources Company and Pioneer Natural Resources USA, Inc., by
which Pioneer USA is soliciting proxies to be voted at a special meeting of
limited partners of the partnership. The purpose of the special meeting is for
you to vote upon the merger of the partnership with and into Pioneer USA that,
if completed, will result in your receiving common stock of Pioneer Natural
Resources Company and cash for your partnership interests.

     This document contains the following information concerning Parker &
Parsley 81-I, Ltd.:

     o    A table containing:

          --   the aggregate initial investment by the limited partners

          --   the aggregate historical limited partner distributions through
               March 31, 2001

          --   the aggregate merger value attributable to partnership interests
               of limited partners, excluding Pioneer USA

          --   the merger value per $1,000 limited partner investment as of
               March 31, 2001

          --   the merger value per $1,000 limited partner investment as a
               multiple of distributions for the 12 months ended March 31, 2001

          --   the book value per $1,000 limited partner investment as of March
               31, 2001 and as of December 31, 2000

          --   the going concern value per $1,000 limited partner investment as
               of March 31, 2001

          --   the liquidation value per $1,000 limited partner investment as of
               March 31, 2001

          --   the ordinary tax loss per $1,000 limited partner investment in
               year of initial investment

     o    Information about the legal opinion for the limited partners

     o    The partnership's financial statements, including management's
          discussion and analysis of financial condition and results of
          operations, for the three months ended March 31, 2001

     o    The partnership's financial statements, including management's
          discussion and analysis of financial condition and results of
          operations, for the year ended December 31, 2000

     o    Selected historical financial data for the partnership for the three
          months ended March 31, 2001 and 2000 and the five years ended December
          31, 2000



                                      -1-

   151


                           PARKER & PARSLEY 81-I, LTD.

                         SUPPLEMENTAL INFORMATION TABLE


                                                                                          
Aggregate Initial Investment by the Limited Partners(a)                                      $   7,410

Aggregate Historical Limited Partner Distributions through March 31, 2001(a)                 $   4,763

Aggregate Merger Value Attributable to Partnership Interests of Limited Partners,            $     625
Excluding Pioneer USA(a)

Merger Value per $1,000 Limited Partner Investment as of March 31, 2001(b)                   $   89.51

Merger Value per $1,000 Limited Partner Investment as a Multiple of Distributions for the         4.28 times
12 Months ended March 31, 2001(b)

Book Value per $1,000 Limited Partner Investment:

          --   as of March 31, 2001(b)                                                       $

          --   as of December 31, 2000(b)                                                    $   20.30

Going Concern Value per $1,000 Limited Partner Investment as of March 31, 2001(b)            $   79.71

Liquidation Value per $1,000 Limited Partner Investment as of March 31, 2001(b)              $   87.13

Ordinary Tax Loss per $1,000 Limited Partner Investment in Year of Initial Investment        $     320
(b), (c)

-----------

(a)  Stated in thousands.

(b)  Interests in some partnerships were sold in units at prices other than
     $1,000. We have presented this information based on a $1,000 initial
     investment for ease of use and comparison among partnerships. You should
     not assume that the amount shown per $1,000 investment is the same as the
     value or amount attributable to a single unit investment.

(c)  Your ability to use your distributive share of the partnership's loss to
     offset your other income may have been subject to certain limitations at
     your level as a partner, and you may therefore wish to consult your tax
     advisor to determine the additional value, if any, actually realized by you
     in your particular circumstances.


          INFORMATION ABOUT THE LEGAL OPINION FOR THE LIMITED PARTNERS

     The partnership agreement for the partnership requires that special legal
counsel render an opinion on behalf of the limited partners to Pioneer USA that
(1) neither the grant nor the exercise of the right to approve the merger of the
partnership by its limited partners will adversely affect the federal income tax
classification of the partnership or any of its limited partners; and (2)
neither the grant nor exercise of such right will result in the loss of any
limited partner's limited liability. In addition, the counsel designated to
render the opinion must be counsel other than counsel to Pioneer USA or the
partnership. Both the designated counsel and the legal opinion must be approved
by the limited partners. Pioneer USA has retained __________ of Dallas, Texas
for the purpose of rendering this legal opinion on behalf of the limited
partners to Pioneer USA. The merger proposals include an approval of that
counsel and the form of its opinion. A copy of the opinion is attached as an
exhibit to the merger proposals.



                                      -2-
   152
                           PARKER & PARSLEY 81-I, LTD.
                          (A Texas Limited Partnership)


                              FINANCIAL STATEMENTS
                                      WITH
                          INDEPENDENT AUDITORS' REPORT


                           December 31, 2000 and 1999




   153





                          INDEPENDENT AUDITORS' REPORT



The Partners
Parker & Parsley 81-I, Ltd.
  (A Texas Limited Partnership):

We have audited the balance sheets of Parker & Parsley 81-I, Ltd. as of December
31, 2000 and 1999, and the related statements of operations, partners' capital
and cash flows for each of the three years in the period ended December 31,
2000. These financial statements are the responsibility of the Partnership's
management. Our responsibility is to express an opinion on these financial
statements based on our audits.

We conducted our audits in accordance with auditing standards generally accepted
in the United States. Those standards require that we plan and perform the audit
to obtain reasonable assurance about whether the financial statements are free
of material misstatement. An audit includes examining, on a test basis, evidence
supporting the amounts and disclosures in the financial statements. An audit
also includes assessing the accounting principles used and significant estimates
made by management, as well as evaluating the overall financial statement
presentation. We believe that our audits provide a reasonable basis for our
opinion.

In our opinion, the financial statements referred to above present fairly, in
all material respects, the financial position of Parker & Parsley 81-I, Ltd. as
of December 31, 2000 and 1999, and the results of its operations and its cash
flows for each of the three years in the period ended December 31, 2000, in
conformity with accounting principles generally accepted in the United States.



                                      Ernst & Young LLP


Dallas, Texas
March 9, 2001



                                       2
   154


                           PARKER & PARSLEY 81-I, LTD.
                          (A Texas Limited Partnership)

                                 BALANCE SHEETS
                                   December 31





                                                                             2000                 1999
                                                                       ----------------     ----------------
                     ASSETS

                                                                                      
Current assets:
  Cash                                                                 $       38,546       $       38,716
  Accounts receivable - oil and gas sales                                      63,269               34,340
                                                                         ------------         ------------

          Total current assets                                                101,815               73,056
                                                                         ------------         ------------

Oil and gas properties - at cost, based on the
  successful efforts accounting method                                      5,245,144            5,240,632
Accumulated depletion                                                      (5,142,190)          (5,133,431)
                                                                         ------------         ------------

          Net oil and gas properties                                          102,954              107,201
                                                                         ------------         ------------

                                                                       $      204,769       $      180,257
                                                                        =============        =============

LIABILITIES AND PARTNERS' CAPITAL

Current liabilities:
  Accounts payable - affiliate                                         $        8,817       $       10,041

Partners' capital:
  General partners                                                             45,564               38,221
  Limited partners (1,482 interests)                                          150,388              131,995
                                                                         ------------         ------------

                                                                              195,952              170,216
                                                                         ------------         ------------

                                                                       $      204,769       $      180,257
                                                                        =============        =============
















   The accompanying notes are an integral part of these financial statements.



                                       3
   155


                           PARKER & PARSLEY 81-I, LTD.
                          (A Texas Limited Partnership)

                            STATEMENTS OF OPERATIONS
                         For the years ended December 31






                                                        2000        1999        1998
                                                     ---------   ---------   ---------

                                                                    
Revenues:
  Oil and gas                                        $ 416,230   $ 260,652   $ 199,789
  Interest                                               3,071       1,858       2,462
  Gain on disposition of assets                             --          --          67
                                                     ---------   ---------   ---------

                                                       419,301     262,510     202,318
                                                     ---------   ---------   ---------

Costs and expenses:
  Oil and gas production                               174,233     165,810     157,631
  General and administrative                            15,697      13,087       8,892
  Impairment of oil and gas properties                      --          --      50,343
  Depletion                                              8,759      11,881     116,799
                                                     ---------   ---------   ---------

                                                       198,689     190,778     333,665
                                                     ---------   ---------   ---------

Net income (loss)                                    $ 220,612   $  71,732   $(131,347)
                                                     =========   =========   =========

Allocation of net income (loss):
  General partners                                   $  56,242   $  19,205   $  (7,775)
                                                     =========   =========   =========

  Limited partners                                   $ 164,370   $  52,527   $(123,572)
                                                     =========   =========   =========

Net income (loss) per limited partnership interest   $  110.91   $   35.44   $  (83.38)
                                                     =========   =========   =========







   The accompanying notes are an integral part of these financial statements.



                                       4
   156


                           PARKER & PARSLEY 81-I, LTD.
                          (A Texas Limited Partnership)

                         STATEMENTS OF PARTNERS' CAPITAL






                                                                           General              Limited
                                                                           partners             partners               Total
                                                                        --------------       --------------       ---------------
                                                                                                         
Partners' capital at January 1, 1998                                    $       52,826       $      295,972       $     348,798

   Distributions                                                               (10,054)             (45,727)            (55,781)

   Net loss                                                                     (7,775)            (123,572)           (131,347)
                                                                          ------------         ------------         -----------

Partners' capital at December 31, 1998                                          34,997              126,673             161,670

   Distributions                                                               (15,981)             (47,205)            (63,186)

   Net income                                                                   19,205               52,527              71,732
                                                                          ------------         ------------         -----------

Partners' capital at December 31, 1999                                          38,221              131,995             170,216

   Distributions                                                               (48,899)            (145,977)           (194,876)

   Net income                                                                   56,242              164,370             220,612
                                                                          ------------         ------------         -----------

Partners' capital at December 31, 2000                                  $       45,564       $      150,388       $     195,952
                                                                         =============        =============        ============






















   The accompanying notes are an integral part of these financial statements.



                                       5
   157


                          PARKER & PARSLEY 81-I, LTD.
                         (A Texas Limited Partnership)

                            STATEMENTS OF CASH FLOWS
                        For the years ended December 31





                                                                             2000                 1999                 1998
                                                                        --------------       --------------       --------------

                                                                                                        
Cash flows from operating activities:
   Net income (loss)                                                    $     220,612        $      71,732       $     (131,347)
   Adjustments to reconcile net income (loss) to
      net cash provided by operating activities:
         Impairment of oil and gas properties                                     -                    -                 50,343
         Depletion                                                              8,759               11,881              116,799
         Gain on disposition of assets                                            -                    -                    (67)
   Changes in assets and liabilities:
         Accounts receivable                                                  (28,929)             (11,525)              12,794
         Accounts payable                                                      (1,224)               2,906               (3,523)
                                                                          -----------           ----------         ------------

             Net cash provided by operating activities                        199,218               74,994               44,999
                                                                          -----------          -----------         ------------

Cash flows from investing activities:
   Additions to oil and gas properties                                         (4,512)              (3,421)              (2,481)
   Proceeds from asset dispositions                                               -                    -                 14,234
                                                                          -----------          -----------         ------------

             Net cash provided by (used in) investing activities               (4,512)              (3,421)              11,753
                                                                          -----------          -----------         ------------

Cash flows used in financing activities:
   Cash distributions to partners                                            (194,876)             (63,186)             (55,781)
                                                                          -----------          -----------         ------------

Net increase (decrease) in cash                                                  (170)               8,387                  971
Cash at beginning of year                                                      38,716               30,329               29,358
                                                                          -----------          -----------         ------------

Cash at end of year                                                     $      38,546        $      38,716       $       30,329
                                                                         ============         ============        =============




   The accompanying notes are an integral part of these financial statements.



                                       6
   158


                           PARKER & PARSLEY 81-I, LTD.
                          (A Texas Limited Partnership)

                          NOTES TO FINANCIAL STATEMENTS
                        December 31, 2000, 1999 and 1998


NOTE 1. ORGANIZATION AND NATURE OF OPERATIONS

        Parker & Parsley 81-I, Ltd. (the "Partnership") is a limited partnership
organized in 1981 under the laws of the State of Texas. The Partnership's
general partners are Pioneer Natural Resources USA, Inc. ("Pioneer USA") and P&P
Employees 81-I, Ltd. ("EMPL"). The Partnership's managing general partner is
Pioneer USA.

        The Partnership engages in oil and gas development and production in
Texas and is not involved in any industry segment other than oil and gas.

NOTE 2. SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES

        A summary of the significant accounting policies consistently applied in
the preparation of the accompanying financial statements follows:

        Oil and gas properties - The Partnership utilizes the successful efforts
method of accounting for its oil and gas properties and equipment. Under this
method, all costs associated with productive wells and nonproductive development
wells are capitalized while nonproductive exploration costs are expensed.
Capitalized costs relating to proved properties are depleted using the
unit-of-production method on a property-by-property basis based on proved oil
(dominant mineral) reserves as evaluated by independent petroleum consultants.
The carrying amounts of properties sold or otherwise disposed of and the related
allowances for depletion are eliminated from the accounts and any gain or loss
is included in results of operations.

        Impairment of long-lived assets - In accordance with Statement of
Financial Accounting Standards No. 121, "Accounting for the Impairment of
Long-Lived Assets and for Long-Lived Assets to be Disposed Of" ("SFAS 121"), the
Partnership reviews its long-lived assets to be held and used on an individual
property basis, including oil and gas properties accounted for under the
successful efforts method of accounting, whenever events or circumstances
indicate that the carrying value of those assets may not be recoverable. An
impairment loss is indicated if the sum of the expected future cash flows is
less than the carrying amount of the assets. In this circumstance, the
Partnership recognizes an impairment loss for the amount by which the carrying
amount of the asset exceeds the estimated fair value of the asset.

        Use of estimates in the preparation of financial statements -
Preparation of the accompanying financial statements in conformity with
generally accepted accounting principles requires management to make estimates
and assumptions that affect the reported amounts of assets and liabilities and
disclosure of contingent assets and liabilities at the date of the financial
statements and the reported amounts of revenues and expenses during the
reporting periods. Actual results could differ from those estimates.



                                       7
   159

        Net income (loss) per limited partnership interest - The net income
(loss) per limited partnership interest is calculated by using the number of
outstanding limited partnership interests.

        Income taxes - A Federal income tax provision has not been included in
the financial statements as the income of the Partnership is included in the
individual Federal income tax returns of the respective partners.

        Statements of cash flows - For purposes of reporting cash flows, cash
includes depository accounts held by banks.

        General and administrative expenses - General and administrative
expenses are allocated in part to the Partnership by the managing general
partner. Allocated expenses are determined by the managing general partner based
upon the level of activity of the Partnership relative to the non-partnership
activities of the managing general partner. The method of allocation has been
consistent over the past several years with certain modifications incorporated
to reflect changes in Pioneer USA's overall business activities.

        Reclassifications - Certain reclassifications may have been made to the
1999 and 1998 financial statements to conform to the 2000 financial statement
presentations.

        Environmental - The Partnership is subject to extensive federal, state
and local environmental laws and regulations. These laws, which are constantly
changing, regulate the discharge of materials into the environment and may
require the Partnership to remove or mitigate the environmental effects of the
disposal or release of petroleum or chemical substances at various sites.
Environmental expenditures are expensed or capitalized depending on their future
economic benefit. Expenditures that relate to an existing condition caused by
past operations and that have no future economic benefits are expensed.
Liabilities for expenditures of a noncapital nature are recorded when
environmental assessment and/or remediation is probable, and the costs can be
reasonably estimated. Such liabilities are generally undiscounted unless the
timing of cash payments for the liability or component are fixed or reliably
determinable. No such liabilities have been accrued as of December 31, 2000.

        Revenue recognition - The Partnership uses the entitlements method of
accounting for oil, natural gas liquids ("NGLs") and natural gas revenues.

NOTE 3. IMPAIRMENT OF LONG-LIVED ASSETS

        In accordance with SFAS 121, the Partnership reviews its proved oil and
gas properties for impairment whenever events and circumstances indicate a
decline in the recoverability of the carrying value of the Partnership's oil and
gas properties. The Partnership has estimated the expected future cash flows of
its oil and gas properties as of December 31, 2000, 1999 and 1998, based on
proved reserves, and compared such estimated future cash flows to the respective
carrying amount of the oil and gas properties to determine if the carrying
amounts were likely to be recoverable. For those proved oil and gas properties
for which the carrying amount exceeded the estimated future cash flows, an
impairment was determined to exist; therefore, the Partnership adjusted the
carrying amount of those oil and gas properties to their fair value as
determined by discounting their expected future cash flows at a discount rate
commensurate with the risks involved



                                       8
   160

in the industry. As a result, the Partnership recognized a non-cash impairment
provision of $50,343 related to its proved oil and gas properties during 1998.

NOTE 4. INCOME TAXES

        The financial statement basis of the Partnership's net assets and
liabilities was $308,345 less than the tax basis at December 31, 2000.

        The following is a reconciliation of net income (loss) per statements of
operations with the net income per Federal income tax returns for the years
ended December 31:



                                                                              2000                1999                1998
                                                                         --------------      --------------      --------------

                                                                                                        
        Net income (loss) per statements of operations                   $     220,612       $      71,732       $    (131,347)
        Depletion and depreciation provisions for tax
           reporting purposes less than amounts for
           financial reporting purposes                                          6,157               9,884             114,643
        Impairment of oil and gas properties for
           financial reporting purposes                                            -                   -                50,343
        Other, net                                                                (447)                (62)                 81
                                                                           -----------        ------------         -----------

                Net income per Federal income tax returns                $     226,322       $      81,554       $      33,720
                                                                          ============        ============        ============


NOTE 5. OIL AND GAS PRODUCING ACTIVITIES

        The following is a summary of the costs incurred, whether capitalized or
expensed, related to the Partnership's oil and gas producing activities for the
years ended December 31:



                                                                             2000                 1999                 1998
                                                                        --------------       --------------       --------------

                                                                                                        
        Property acquisition costs                                      $        4,512       $       3,421       $        2,481
                                                                         =============        ============        =============


        Capitalized oil and gas properties consist of the following:



                                                                                                   2000                1999
                                                                                             ----------------    ----------------
                                                                                                           
        Proved properties:
           Property acquisition costs                                                       $       156,084      $       156,084
           Completed wells and equipment                                                          5,089,060            5,084,548
                                                                                              -------------        -------------

                                                                                                  5,245,144            5,240,632
        Accumulated depletion                                                                    (5,142,190)          (5,133,431)
                                                                                              -------------        -------------

                Net oil and gas properties                                                  $       102,954      $       107,201
                                                                                             ==============       ==============



NOTE 6. RELATED PARTY TRANSACTIONS

        Pursuant to the limited partnership agreement, the Partnership had the
following related party transactions with the managing general partner during
the years ended December 31:



                                       9
   161



                                                                              2000                1999                 1998
                                                                         --------------      --------------       --------------

                                                                                                         
        Payment of lease operating and supervision
           charges in accordance with standard industry
           operating agreements                                          $      78,719       $      73,881        $     76,809

        Reimbursement of general and administrative
           expenses                                                      $      12,487       $       7,820        $      6,250


        Pioneer USA, EMPL and the Partnership are parties to the Partnership
agreement. EMPL is a limited partnership in which Pioneer USA owns 60% and the
remaining portion is owned by former affiliates.

        The costs and revenues of the Partnership are allocated as follows:



                                                                                        General                   Limited
                                                                                        partners                  partners
                                                                                        --------                  --------
                                                                                                               
     Revenues:
        Proceeds from property dispositions prior to cost
          recovery                                                                         10%                       90%
        All other Partnership revenues                                                     25%                       75%
     Costs and expenses:
        Lease acquisition costs, drilling and completion
          costs and all other costs                                                        10%                       90%
        Operating costs, direct costs and general and
          administrative expenses                                                          25%                       75%


NOTE 7. OIL AND GAS INFORMATION (UNAUDITED)

        The following table presents information relating to the Partnership's
estimated proved oil and gas reserves at December 31, 2000, 1999 and 1998 and
changes in such quantities during the years then ended. All of the Partnership's
reserves are proved developed and located within the United States. The
Partnership's reserves are based on an evaluation prepared by Williamson
Petroleum Consultants, Inc., an independent petroleum consultant, using criteria
established by the Securities and Exchange Commission.




                                       10
   162




                                                Oil and NGLs            Gas
                                                  (bbls)               (mcf)
                                                 --------            --------

                                                              
Net proved reserves at January 1, 1998            131,090             275,544
Revisions                                         (70,930)           (119,307)
Production                                        (13,937)            (24,638)
                                                 --------            --------

Net proved reserves at December 31, 1998           46,223             131,599
Revisions                                         160,567             219,656
Production                                        (14,970)            (28,708)
                                                 --------            --------

Net proved reserves at December 31, 1999          191,820             322,547
Revisions                                          33,336             130,129
Production                                        (13,976)            (25,901)
                                                 --------            --------

Net proved reserves at December 31, 2000          211,180             426,775
                                                 ========            ========


        As of December 31, 2000, the estimated present value of future net
revenues of proved reserves, calculated using December 31, 2000 prices of $26.64
per barrel of oil, $13.30 per barrel of NGLs and $7.65 per mcf of gas,
discounted at 10% was approximately $1,915,000 and undiscounted was $3,748,000.

        Numerous uncertainties exist in estimating quantities of proved reserves
and future net revenues therefrom. The estimates of proved reserves and related
future net revenues set forth in this Report are based on various assumptions,
which may ultimately prove to be inaccurate. Therefore, such estimates should
not be construed as estimates of the current market value of the Partnership's
proved reserves. The Partnership emphasizes that reserve estimates are
inherently imprecise and, accordingly, the estimates are expected to change as
future information becomes available.

Disclosures about Oil & Gas Producing Activities

Standardized Measure of Discounted Future Net Cash Flows

       The standardized measure of discounted future net cash flows is computed
by applying year-end prices of oil and gas (with consideration of price changes
only to the extent provided by contractual arrangements) to the estimated future
production of proved oil and gas reserves less estimated future expenditures
(based on year-end costs) to be incurred in developing and producing the proved
reserves, discounted using a rate of 10% per year to reflect the estimated
timing of the future cash flows. A Federal income tax provision has not been
calculated as the income of the Partnership is included in the individual
Federal income tax returns of the respective partners.

       Discounted future cash flow estimates like those shown below are not
intended to represent estimates of the fair value of oil and gas properties.
Estimates of fair value should also consider anticipated future oil and gas
prices, interest rates, changes in development and production costs and risks
associated with future production. Because of these and other considerations,
any estimate of fair value is necessarily subjective and imprecise.






                                       11
   163




                                                                                  For the years ended December 31,
                                                                        ---------------------------------------------------
                                                                              2000                1999               1998
                                                                        ----------------    ----------------   ----------------
                                                                                             (in thousands)
                                                                                                      
Oil and gas producing activities:
   Future cash inflows                                                  $         7,853     $        4,776     $           583
   Future production costs                                                       (4,105)            (3,078)               (433)
                                                                          -------------       ------------       -------------

                                                                                  3,748              1,698                 150
   10% annual discount factor                                                    (1,833)              (734)                (64)
                                                                          -------------       ------------       -------------

   Standardized measure of discounted future net cash flows             $         1,915     $          964     $            86
                                                                         ==============      =============      ==============





                                                                                  For the years ended December 31,
                                                                        ---------------------------------------------------
                                                                              2000                1999               1998
                                                                        ----------------    ----------------   ----------------
                                                                                             (in thousands)
                                                                                                      
   Oil and Gas Producing Activities:
      Oil and gas sales, net of production costs                        $          (242)    $          (95)    $          (42)
      Net changes in prices and production costs                                    888                180               (301)
      Revisions of previous quantity estimates                                      415                788               (112)
      Accretion of discount                                                          96                  8                 52
      Changes in production rates, timing and other                                (206)                (3)               (33)
                                                                          -------------       ------------       ------------

      Change in present value of future net revenues                                951                878               (436)
                                                                          -------------       ------------       ------------

      Balance, beginning of year                                                    964                 86                522
                                                                          -------------       ------------       ------------

      Balance, end of year                                              $         1,915     $          964     $           86
                                                                         ==============      =============      =============


NOTE 8. MAJOR CUSTOMERS

        The following table reflects the major customers of the Partnership's
oil and gas sales (a major customer is defined as a customer whose sales exceed
10% of total sales) during the years ended December 31:


                                                                                2000                1999               1998
                                                                              --------            --------           --------

                                                                                                            
                    Plains Marketing, L.P.                                       54%                 51%                 -
                    Genesis Crude Oil, L.P.                                       -                   -                 59%
                    Western Gas Resources, Inc.                                   -                   6%                18%
                    Exxon Corporation                                             8%                  7%                11%


        At December 31, 2000, the amount receivable from Plains Marketing, L.P.
was $19,892 which is included in the caption "Accounts receivable - oil and gas
sales" in the accompanying Balance Sheet.

        Pioneer USA is of the opinion that the loss of any one purchaser would
not have an adverse effect on the ability of the Partnership to sell its oil,
NGLs and gas production.







                                       12
   164


NOTE 9. PARTNERSHIP AGREEMENT

        The following is a brief summary of the more significant provisions of
the limited partnership agreement:

        General partners - The general partners of the Partnership are Pioneer
        USA and EMPL. Pioneer USA, the managing general partner, has the power
        and authority to manage, control and administer all Partnership affairs.
        As managing general partner and operator of the Partnership's
        properties, all production expenses are incurred by Pioneer USA and
        billed to the Partnership. The majority of the Partnership's oil and gas
        revenues are received directly by the Partnership, however, a portion of
        the oil and gas revenue is initially received by Pioneer USA prior to
        being paid to the Partnership.

        Limited partner liability - The maximum amount of liability of any
        limited partner is the total contributions of such partner plus his
        share of any undistributed profits.

        Initial capital contributions - The limited partners entered into
        subscription agreements for aggregate capital contributions of
        $7,410,000. The general partners are required to contribute amounts
        equal to 10% of Partnership expenditures for lease acquisition, drilling
        and completion and 25% of direct, general and administrative and
        operating expenses.



                                       13




   165
                           PARKER & PARSLEY 81-I, LTD.
                          (A TEXAS LIMITED PARTNERSHIP)

THIS REPORT CONTAINS FORWARD LOOKING STATEMENTS THAT INVOLVE RISKS AND
UNCERTAINTIES. ACCORDINGLY, NO ASSURANCES CAN BE GIVEN THAT THE ACTUAL EVENTS
AND RESULTS WILL NOT BE MATERIALLY DIFFERENT THAN THE ANTICIPATED RESULTS
DESCRIBED IN THE FORWARD LOOKING STATEMENTS.

MANAGEMENT'S DISCUSSION AND ANALYSIS OF FINANCIAL CONDITION AND
     RESULTS OF OPERATIONS

Results of operations

2000 compared to 1999

The Partnership's oil and gas revenues increased 60% to $416,230 for 2000 as
compared to $260,652 in 1999. The increase in revenues resulted from higher
average prices received, offset by a decrease in production. In 2000, 8,793
barrels of oil, 5,183 barrels of natural gas liquids ("NGLs") and 25,901 mcf of
gas were sold, or 18,293 barrel of oil equivalents ("BOEs"). In 1999, 9,249
barrels of oil, 5,721 barrels of NGLs and 28,708 mcf of gas were sold, or 19,755
BOEs. Due to the decline characteristics of the Partnership's oil and gas
properties, management expects a certain amount of decline in production in the
future until the Partnership's economically recoverable reserves are fully
depleted.

The average price received per barrel of oil increased $12.32, or 73%, from
$16.94 in 1999 to $29.26 in 2000. The average price received per barrel of NGLs
increased $5.38, or 58%, from $9.22 in 1999 to $14.60 in 2000. The average price
received per mcf of increased 81% from $1.78 in 1999 to $3.22 in 2000. The
market price for oil and gas has been extremely volatile in the past decade, and
management expects a certain amount of volatility to continue in the foreseeable
future. The Partnership may therefore sell its future oil and gas production at
average prices lower or higher than that received in 2000.

Total costs and expenses increased in 2000 to $198,689 as compared to $190,778
in 1999, an increase of $7,911, or 4%. The increase was primarily due to an
increase in production costs and general and administrative expenses ("G&A"),
offset by a decline in depletion.

Production costs were $174,233 in 2000 and $165,810 in 1999, resulting in an
$8,423 increase, or 5%. The increase was primarily due to higher production
taxes associated with higher oil and gas prices, offset by less well maintenance
costs.

G&A's components are independent accounting and engineering fees and managing
general partner personnel and operating costs. During this period, G&A increased
20% from $13,087 in 1999 to $15,697 in 2000, primarily due to a higher
percentage of the managing general partner's G&A being allocated (limited to 3%
of oil and gas revenues) as a result of increased oil and gas revenues. The
Partnership paid the managing general partner $12,487 in 2000 and $7,820 in 1999
for G&A incurred on behalf of the Partnership. The remaining G&A was paid
directly by the Partnership. The managing general partner determines the
allocated expenses based upon the level of activity of the Partnership relative
to the non-partnership activities of the managing general partner. The method of
allocation has been consistent over the past several years with certain
modifications incorporated to reflect changes in Pioneer USA's overall business
activities.

Depletion was $8,759 in 2000 as compared to $11,881 in 1999, representing a
decrease of $3,122, or 26%. This decrease was primarily due to a 20,821 barrels
of oil increase in proved reserves during 2000 as a result of the higher
commodity prices.

1999 compared to 1998

The Partnership's 1999 oil and gas revenues increased 30% to $260,652 from
$199,789 in 1998. The increase in revenues resulted from higher average prices
received and an increase in production. In 1999, 9,249 barrels of oil, 5,721
barrels of NGLs and 28,708 mcf of gas were sold, or 19,755 BOEs. In 1998, 9,634
barrels of oil, 4,303 barrels of NGLs and 24,638 mcf of gas were sold, or 18,043
BOEs.



   166

The average price received per barrel of oil increased $3.61, or 27%, from
$13.33 in 1998 to $16.94 in 1999. The average price received per barrel of NGLs
increased $2.82, or 44%, from $6.40 in 1998 to $9.22 in 1999. The average price
received per mcf of gas remained unchanged at $1.78 in 1998 and 1999.

Total costs and expenses decreased in 1999 to $190,778 as compared to $333,665
in 1998, a decrease of $142,887, or 43%. The decrease was primarily due to
declines in depletion and the impairment of oil and gas properties, offset by an
increase in production costs and G&A.

Production costs were $165,810 in 1999 and $157,631 in 1998, resulting in an
$8,179 increase, or 5%. The increase was due to additional well maintenance
costs incurred to stimulate well production and an increase in production taxes
due to increased oil and gas revenues, offset by a decline in ad valorem taxes.

During this period, G&A increased 47% from $8,892 in 1998 to $13,087 in 1999
primarily due to a higher percentage of the managing general partner's G&A being
allocated (limited to 3% of oil and gas revenues) as a result of increased oil
and gas revenues. The Partnership paid the managing general partner $7,820 in
1999 and $6,250 in 1998 for G&A incurred on behalf of the Partnership.

In accordance with Statement of Financial Accounting Standards No. 121,
"Accounting for the Impairment of Long-Lived Assets and for Long-Lived Assets to
be Disposed Of" ("SFAS 121"), the managing general partner reviews the
Partnership's oil and gas properties for impairment whenever events or
circumstances indicate a decline in the recoverability of the carrying value of
the Partnership's assets may have occurred. As a result of the review and
evaluation of its long-lived assets for impairment, the Partnership recognized a
non-cash charge of $50,343 related to its oil and gas properties during 1998.

Depletion was $11,881 in 1999 compared to $116,799 in 1998, representing a
decrease of $104,918, or 90%. This decrease was the result of a combination of
factors that included an increase in proved reserves of 104,672 barrels of oil
during 1999 as a result of the higher commodity prices, a reduction in the
Partnership's net depletable basis from charges taken in accordance with SFAS
121 during the fourth quarter of 1998 and a decline in oil production of 385
barrels for the period ended December 31, 1999 compared to the same period in
1998.

Petroleum industry

The petroleum industry has been characterized by volatile oil, NGL and natural
gas commodity prices and relatively stable supplier costs during the three years
ended December 31, 2000. During 1998, weather patterns, regional economic
recessions and political matters combined to cause worldwide oil supplies to
exceed demand resulting in a substantial decline in oil prices. Also during
1998, but to a lesser extent, market prices for natural gas declined. During
1999 and 2000, the Organization of Petroleum Exporting Countries ("OPEC") and
certain other crude oil exporting nations announced reductions in their planned
export volumes. Those announcements, together with the enactment of the
announced reductions in export volumes, had a positive impact on world oil
prices, as have overall natural gas supply and demand fundamentals on North
American natural gas prices. Although the favorable commodity price environment
and stable field service cost environment is expected to continue during 2001,
there is no assurance that commodity prices will not return to a less favorable
level or that field service costs will not escalate in the future, both of which
could negatively impact the Partnership's future results of operations and cash
distributions.

Liquidity and capital resources

Net Cash Provided by Operating Activities

Net cash provided by operating activities increased $124,224 during the year
ended December 31, 2000 from 1999. This increase was due to an increase in oil
and gas sales receipts of $156,791, offset by increases in production costs paid
of $8,423, G&A expenses paid of $2,610 and working capital of $21,534. The
increase in oil and gas receipts resulted from the increase in commodity prices
during 2000 which contributed an additional $187,015 to oil and gas receipts,
offset by $30,224 resulting from the decline in production during 2000. The
increase in production costs was primarily due to increased production taxes
associated with higher oil and gas prices, offset by lower well maintenance
costs. The increase in G&A was primarily due to higher percentage of the
managing general partner's G&A being allocated (limited to 3% of oil and gas
revenues) as a result of increased oil and gas revenues.



   167

Net Cash Provided by (Used in) Investing Activities

The Partnership's principal investing activities during 2000 and 1999 included
expenditures related to upgrades of equipment on various oil and gas properties.

Net Cash Used in Financing Activities

In 2000, cash distributions to the partners were $194,876, of which $48,899 was
distributed to the general partners and $145,977 to the limited partners. In
1999, cash distributions to the partners were $63,186, of which $15,981 was
distributed to the general partners and $47,205 to the limited partners.







   168


                           PARKER & PARSLEY 81-I, LTD.

SELECTED FINANCIAL DATA

The following selected financial data for the Partnership should be read in
connection with Management's Discussion and Analysis of Financial Condition and
Results of Operations and the financial statements included in the attached
supplemental information.



                                        Three months
                                            ended
                                          March 31,                       Years ended December 31,
                                   ---------------------   --------------------------------------------------------------
                                     2001        2000         2000         1999         1998         1997         1996
                                   --------   ----------   ----------   ----------   ----------   ----------   ----------
                                                                                          
Operating results:
  Oil and gas sales                $          $   94,181   $  416,230   $  260,652   $  199,789   $  279,957   $  396,128
                                   ========   ==========   ==========   ==========   ==========   ==========   ==========

  Impairment of oil and
    gas properties                 $          $       --   $       --   $       --   $   50,343   $  255,709   $       --
                                   ========   ==========   ==========   ==========   ==========   ==========   ==========

  Gain on litigation
      settlement, net              $          $       --   $       --   $       --   $       --   $       --   $   30,621
                                   ========   ==========   ==========   ==========   ==========   ==========   ==========

  Net income (loss)                $          $   49,539   $  220,612   $   71,732   $ (131,347)  $ (241,864)  $  203,620
                                   ========   ==========   ==========   ==========   ==========   ==========   ==========

  Allocation of net
    income (loss):
         Managing general
           partner                 $          $   12,628   $   56,242   $   19,205   $   (7,775)  $  (11,941)  $   54,950
                                   ========   ==========   ==========   ==========   ==========   ==========   ==========

         Limited partners          $          $   36,911   $  164,370   $   52,527   $ (123,572)  $ (229,923)  $  148,670
                                   ========   ==========   ==========   ==========   ==========   ==========   ==========

  Limited partners' net
    income (loss) per limited
    partnership interest           $          $    24.91   $   110.91   $    35.44   $   (83.38)  $  (155.14)  $   100.32
                                   ========   ==========   ==========   ==========   ==========   ==========   ==========

  Limited partners' cash
    distributions per limited
    partnership interest           $          $    21.18   $    98.50   $    31.85   $    30.85   $    68.90   $   107.95(a)
                                   ========   ==========   ==========   ==========   ==========   ==========   ==========

At year end:
  Total assets                     $          $  187,763   $  204,769   $  180,257   $  168,805   $  359,456   $  734,832
                                   ========   ==========   ==========   ==========   ==========   ==========   ==========


----------

(a)  Including litigation settlement per limited partnership interest of $20.66
     in 1996.


   169
                        PIONEER NATURAL RESOURCES COMPANY
                       PIONEER NATURAL RESOURCES USA, INC.
                            1400 WILLIAMS SQUARE WEST
                            5205 NORTH O'CONNOR BLVD.
                               IRVING, TEXAS 75039

                            SUPPLEMENTAL INFORMATION

                                       OF

            PARKER & PARSLEY 81-II LTD., A TEXAS LIMITED PARTNERSHIP

                                       TO

                  PROXY STATEMENT/PROSPECTUS DATED      , 2001

                                   ----------

                   THE DATE OF THIS SUPPLEMENT IS      , 2001

                                   ----------

     This document contains important information specific to Parker & Parsley
81-II Ltd. and supplements the proxy statement/prospectus dated      , 2001, of
Pioneer Natural Resources Company and Pioneer Natural Resources USA, Inc., by
which Pioneer USA is soliciting proxies to be voted at a special meeting of
limited partners of the partnership. The purpose of the special meeting is for
you to vote upon the merger of the partnership with and into Pioneer USA that,
if completed, will result in your receiving common stock of Pioneer Natural
Resources Company and cash for your partnership interests.

     This document contains the following information concerning Parker &
Parsley 81-II Ltd.:

     o    A table containing:

          --   the aggregate initial investment by the limited partners

          --   the aggregate historical limited partner distributions through
               March 31, 2001

          --   the aggregate merger value attributable to partnership interests
               of limited partners, excluding Pioneer USA

          --   the merger value per $1,000 limited partner investment as of
               March 31, 2001

          --   the merger value per $1,000 limited partner investment as a
               multiple of distributions for the 12 months ended March 31, 2001

          --   the book value per $1,000 limited partner investment as of March
               31, 2001 and as of December 31, 2000

          --   the going concern value per $1,000 limited partner investment as
               of March 31, 2001

          --   the liquidation value per $1,000 limited partner investment as of
               March 31, 2001

          --   the ordinary tax loss per $1,000 limited partner investment in
               year of initial investment

     o    Information about the legal opinion for the limited partners

     o    The partnership's financial statements, including management's
          discussion and analysis of financial condition and results of
          operations, for the three months ended March 31, 2001

     o    The partnership's financial statements, including management's
          discussion and analysis of financial condition and results of
          operations, for the year ended December 31, 2000

     o    Selected historical financial data for the partnership for the three
          months ended March 31, 2001 and 2000 and the five years ended December
          31, 2000

                                      -1-

   170

                           PARKER & PARSLEY 81-II LTD.

                         SUPPLEMENTAL INFORMATION TABLE


                                                                                          
Aggregate Initial Investment by the Limited Partners(a)                                      $   6,440

Aggregate Historical Limited Partner Distributions through March 31, 2001(a)                 $   5,337

Aggregate Merger Value Attributable to Partnership Interests of Limited Partners,            $     479
Excluding Pioneer USA(a)

Merger Value per $1,000 Limited Partner Investment as of March 31, 2001(b)                   $   74.71

Merger Value per $1,000 Limited Partner Investment as a Multiple of Distributions for the         4.65 times
12 Months ended March 31, 2001(b)

Book Value per $1,000 Limited Partner Investment:

          --   as of March 31, 2001(b)                                                       $

          --   as of December 31, 2000(b)                                                    $   84.93

Going Concern Value per $1,000 Limited Partner Investment as of March 31, 2001(b)            $   66.25

Liquidation Value per $1,000 Limited Partner Investment as of March 31, 2001(b)              $   72.80

Ordinary Tax Loss per $1,000 Limited Partner Investment in Year of Initial Investment        $     290
(b), (c)

-----------

(a)  Stated in thousands.

(b)  Interests in some partnerships were sold in units at prices other than
     $1,000. We have presented this information based on a $1,000 initial
     investment for ease of use and comparison among partnerships. You should
     not assume that the amount shown per $1,000 investment is the same as the
     value or amount attributable to a single unit investment.

(c)  Your ability to use your distributive share of the partnership's loss to
     offset your other income may have been subject to certain limitations at
     your level as a partner, and you may therefore wish to consult your tax
     advisor to determine the additional value, if any, actually realized by you
     in your particular circumstances.


          INFORMATION ABOUT THE LEGAL OPINION FOR THE LIMITED PARTNERS

     The partnership agreement for the partnership requires that special legal
counsel render an opinion on behalf of the limited partners to Pioneer USA that
(1) neither the grant nor the exercise of the right to approve the merger of the
partnership by its limited partners will adversely affect the federal income tax
status or classification of the partnership or any of its limited partners; and
(2) neither the grant nor exercise of such right will result in the loss of any
limited partner's limited liability. In addition, the counsel designated to
render the opinion must be counsel other than counsel to Pioneer USA or the
partnership. Both the designated counsel and the legal opinion must be approved
by the limited partners. Pioneer USA has retained __________ of Dallas, Texas
for the purpose of rendering this legal opinion on behalf of the limited
partners to Pioneer USA. The merger proposals include an approval of that
counsel and the form of its opinion. A copy of the opinion is attached as an
exhibit to the merger proposals.


                                      -2-
   171






                          PARKER & PARSLEY 81-II, LTD.
                          (A Texas Limited Partnership)


                              FINANCIAL STATEMENTS
                                      WITH
                          INDEPENDENT AUDITORS' REPORT


                           December 31, 2000 and 1999







   172




                          INDEPENDENT AUDITORS' REPORT



The Partners
Parker & Parsley 81-II, Ltd.
 (A Texas Limited Partnership):

We have audited the balance sheets of Parker & Parsley 81-II, Ltd. as of
December 31, 2000 and 1999, and the related statements of operations, partners'
capital and cash flows for each of the three years in the period ended December
31, 2000. These financial statements are the responsibility of the Partnership's
management. Our responsibility is to express an opinion on these financial
statements based on our audits.

We conducted our audits in accordance with auditing standards generally accepted
in the United States. Those standards require that we plan and perform the audit
to obtain reasonable assurance about whether the financial statements are free
of material misstatement. An audit includes examining, on a test basis, evidence
supporting the amounts and disclosures in the financial statements. An audit
also includes assessing the accounting principles used and significant estimates
made by management, as well as evaluating the overall financial statement
presentation. We believe that our audits provide a reasonable basis for our
opinion.

In our opinion, the financial statements referred to above present fairly, in
all material respects, the financial position of Parker & Parsley 81-II, Ltd. as
of December 31, 2000 and 1999, and the results of its operations and its cash
flows for each of the three years in the period ended December 31, 2000, in
conformity with accounting principles generally accepted in the United States.




                                           Ernst & Young LLP


Dallas, Texas
March 9, 2001



                                       2
   173



                          PARKER & PARSLEY 81-II, LTD.
                          (A Texas Limited Partnership)

                                 BALANCE SHEETS
                                   December 31





                                                         2000        1999
                                                     ----------   ---------
           ASSETS
           ------
                                                           
Current assets:
 Cash                                               $    29,376  $   30,160
 Accounts receivable - oil and gas sales                 64,821      27,908
                                                     ----------   ---------

      Total current assets                               94,197      58,068
                                                     ----------   ---------

Oil and gas properties - at cost, based on the
  successful efforts accounting method                5,345,296   5,338,113
Accumulated depletion                                (4,821,914) (4,776,074)
                                                     ----------   ---------


     Net oil and gas properties                         523,382     562,039
                                                     ----------   ---------

                                                       $617,579  $  620,107
                                                     ==========   =========

LIABILITIES AND PARTNERS' CAPITAL
---------------------------------
Current liabilities:
 Accounts payable - affiliate                       $     9,253  $   10,581

Partners' capital:
  General partners                                       61,405      58,558
  Limited partners (1,153 interests)                    546,921     550,968
                                                     ----------   ---------

                                                        608,326     609,526
                                                     ----------   ---------
                                                    $   617,579  $  620,107
                                                     ==========   =========




   The accompanying notes are an integral part of these financial statements.



                                       3
   174



                          PARKER & PARSLEY 81-II, LTD.
                          (A Texas Limited Partnership)

                            STATEMENTS OF OPERATIONS
                         For the years ended December 31






                                             2000        1999       1998
                                          --------    --------    --------
                                                        
Revenues:
  Oil and gas                            $ 387,180   $ 204,717   $ 209,110
  Interest                                   2,775       1,395       1,725
  Gain on disposition of assets                -           240         -
                                          --------    --------    --------

                                           389,955     206,352     210,835
                                          --------    --------    --------

Costs and expenses:
  Oil and gas production                   189,764     140,847     173,960
  General and administrative                13,791       9,864       7,867
  Impairment of oil and gas properties         -           -        30,131
  Depletion                                 45,840      49,409      95,466
                                          --------    --------    --------

                                           249,395     200,120     307,424
                                          --------    --------    --------

Net income (loss)                        $ 140,560   $   6,232   $ (96,589)
                                          ========    ========    ========

Allocation of net income (loss):
  General partners                       $  41,791   $   8,423   $  (5,308)
                                          ========    ========    ========

  Limited partners                       $  98,769   $  (2,191)  $ (91,281)
                                          ========    ========    ========

Net income (loss) per limited
  partnership interest                   $   85.66   $   (1.90)  $  (79.17)
                                          ========    ========    ========





   The accompanying notes are an integral part of these financial statements.



                                       4
   175



                         PARKER & PARSLEY 81-II, LTD.
                          (A Texas Limited Partnership)

                         STATEMENTS OF PARTNERS' CAPITAL






                                           General      Limited
                                           partners     partners    Total
                                          ---------    ---------  ---------
                                                          
Partners' capital at January 1, 1998      $ 76,354     $706,525   $782,879

   Distributions                           (11,831)     (34,220)   (46,051)

   Net loss                                 (5,308)     (91,281)   (96,589)
                                          ---------    ---------  ---------

Partners' capital at December 31, 1998      59,215      581,024    640,239

   Distributions                            (9,080)     (27,865)   (36,945)

   Net income (loss)                         8,423       (2,191)     6,232
                                          ---------    ---------  ---------

Partners' capital at December 31, 1999      58,558      550,968    609,526

   Distributions                           (38,944)    (102,816)  (141,760)

   Net income                               41,791       98,769    140,560
                                          ---------    ---------  ---------

Partners' capital at December 31, 2000    $ 61,405     $546,921   $608,326
                                          =========    =========  =========






   The accompanying notes are an integral part of these financial statements.



                                       5
   176



                          PARKER & PARSLEY 81-II, LTD.
                          (A Texas Limited Partnership)

                            STATEMENTS OF CASH FLOWS
                         For the years ended December 31






                                                      2000        1999        1998
                                                   ---------    ---------  ---------
                                                                 
Cash flows from operating activities:
  Net income (loss)                                $140,560     $ 6,232    $(96,589)
  Adjustments to reconcile net income (loss) to
   net cash provided by operating activities:
     Impairment of oil and gas properties               -           -        30,131
     Depletion                                       45,840      49,409      95,466
     Gain on disposition of assets                      -          (240)        -
  Changes in assets and liabilities:
     Accounts receivable                            (36,913)     (3,325)     15,443
     Accounts payable                                (1,328)      3,022      (3,482)
                                                   ---------    ---------  ---------

        Net cash provided by operating activities   148,159      55,098      40,969
                                                   ---------    ---------  ---------
Cash flows from investing activities:
  Additions to oil and gas properties                (7,183)     (4,254)     (8,322)
  Proceeds from asset dispositions                      -           690         -
                                                   ---------    ---------  ---------

        Net cash used in investing activities        (7,183)     (3,564)     (8,322)
                                                   ---------    ---------  ---------

Cash flows used in financing activities:
  Cash distributions to partners                   (141,760)    (36,945)    (46,051)
                                                   ---------    ---------  ---------

Net increase (decrease) in cash                        (784)     14,589     (13,404)
Cash at beginning of year                            30,160      15,571      28,975
                                                   ---------    ---------  ---------

Cash at end of year                                $ 29,376     $30,160    $ 15,571
                                                   =========    =========  =========




   The accompanying notes are an integral part of these financial statements.



                                       6
   177



                          PARKER & PARSLEY 81-II, LTD.
                          (A Texas Limited Partnership)

                          NOTES TO FINANCIAL STATEMENTS
                        December 31, 2000, 1999 and 1998


NOTE 1.     ORGANIZATION AND NATURE OF OPERATIONS

     Parker & Parsley 81-II (the "Partnership") is a limited partnership
organized in 1981 under the laws of the State of Texas. The Partnership's
general partners are Pioneer Natural Resources USA, Inc. ("Pioneer USA") and P&P
Employees 81-II, Ltd. ("EMPL"). The Partnership's managing general partner is
Pioneer USA.

     The Partnership engages in oil and gas development and production in Texas
and is not involved in any industry segment other than oil and gas.

NOTE 2.     SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES

     A summary of the significant accounting policies consistently applied in
the preparation of the accompanying financial statements follows:

     Oil and gas properties - The Partnership utilizes the successful efforts
method of accounting for its oil and gas properties and equipment. Under this
method, all costs associated with productive wells and nonproductive development
wells are capitalized while nonproductive exploration costs are expensed.
Capitalized costs relating to proved properties are depleted using the
unit-of-production method on a property-by-property basis based on proved oil
(dominant mineral) reserves as evaluated by independent petroleum consultants.
The carrying amounts of properties sold or otherwise disposed of and the related
allowances for depletion are eliminated from the accounts and any gain or loss
is included in results of operations.

     Impairment of long-lived assets - In accordance with Statement of Financial
Accounting Standards No. 121, "Accounting for the Impairment of Long-Lived
Assets and for Long-Lived Assets to be Disposed Of" ("SFAS 121"), the
Partnership reviews its long-lived assets to be held and used on an individual
property basis, including oil and gas properties accounted for under the
successful efforts method of accounting, whenever events or circumstances
indicate that the carrying value of those assets may not be recoverable. An
impairment loss is indicated if the sum of the expected future cash flows is
less than the carrying amount of the assets. In this circumstance, the
Partnership recognizes an impairment loss for the amount by which the carrying
amount of the asset exceeds the estimated fair value of the asset.

     Use of estimates in the preparation of financial statements - Preparation
of the accompanying financial statements in conformity with generally accepted
accounting principles requires management to make estimates and assumptions that
affect the reported amounts of assets and liabilities and disclosure of
contingent assets and liabilities at the date of the financial statements and
the reported amounts of revenues and expenses during the reporting periods.
Actual results could differ from those estimates.

                                       7
   178

     Net income (loss) per limited partnership interest - The net income (loss)
per limited partnership interest is calculated by using the number of
outstanding limited partnership interests.

     Income taxes - A Federal income tax provision has not been included in the
financial statements as the income of the Partnership is included in the
individual Federal income tax returns of the respective partners.

     Statements of cash flows - For purposes of reporting cash flows, cash
includes depository accounts held by banks.

     General and administrative expenses - General and administrative expenses
are allocated in part to the Partnership by the managing general partner.
Allocated expenses are determined by the managing general partner based upon the
level of activity of the Partnership relative to the non-partnership activities
of the managing general partner. The method of allocation has been consistent
over the past several years with certain modifications incorporated to reflect
changes in Pioneer USA's overall business activities.

     Reclassifications - Certain reclassifications may have been made to the
1999 and 1998 financial statements to conform to the 2000 financial statement
presentations.

     Environmental - The Partnership is subject to extensive federal, state and
local environmental laws and regulations. These laws, which are constantly
changing, regulate the discharge of materials into the environment and may
require the Partnership to remove or mitigate the environmental effects of the
disposal or release of petroleum or chemical substances at various sites.
Environmental expenditures are expensed or capitalized depending on their future
economic benefit. Expenditures that relate to an existing condition caused by
past operations and that have no future economic benefits are expensed.
Liabilities for expenditures of a noncapital nature are recorded when
environmental assessment and/or remediation is probable, and the costs can be
reasonably estimated. Such liabilities are generally undiscounted unless the
timing of cash payments for the liability or component are fixed or reliably
determinable. No such liabilities have been accrued as of December 31, 2000.

     Revenue recognition - The Partnership uses the entitlements method of
accounting for oil, natural gas liquids ("NGLs") and natural gas revenues.

NOTE 3.    IMPAIRMENT OF LONG-LIVED ASSETS

     In accordance with SFAS 121, the Partnership reviews its proved oil and gas
properties for impairment whenever events and circumstances indicate a decline
in the recoverability of the carrying value of the Partnership's oil and gas
properties. The Partnership has estimated the expected future cash flows of its
oil and gas properties as of December 31, 2000, 1999 and 1998, based on proved
reserves, and compared such estimated future cash flows to the respective
carrying amount of the oil and gas properties to determine if the carrying
amounts were likely to be recoverable. For those proved oil and gas properties
for which the carrying amount exceeded the estimated future cash flows, an
impairment was determined to exist; therefore, the Partnership adjusted the
carrying amount of those oil and gas properties to their fair value as
determined by discounting their expected future cash flows at a discount rate
commensurate with the risks involved

                                       8
   179

in the industry. As a result, the Partnership recognized a non-cash impairment
provision of $30,131 related to its proved oil and gas properties during 1998.

NOTE 4.    INCOME TAXES

     The financial statement basis of the Partnership's net assets and
liabilities was $172,373 greater than the tax basis at December 31, 2000.

     The following is a reconciliation of net income (loss) per statements of
operations with the net income per Federal income tax returns for the years
ended December 31:




                                                           2000       1999     1998
                                                        ---------   -------- ---------

                                                                    
    Net income (loss) per statements of operations     $ 140,560    $ 6,232  $ (96,589)
    Depletion and depreciation provisions for tax
     reporting purposes less than amounts for
     financial reporting purposes                         41,011     44,867     91,653
    Impairment of oil and gas properties for
     financial reporting purposes                           -          -        30,131
    Other, net                                              (482)      (178)       454
                                                        ---------   -------- ---------

         Net income per Federal income tax returns      $181,089   $ 50,921   $ 25,649
                                                        =========   ======== =========



NOTE 5.     OIL AND GAS PRODUCING ACTIVITIES

The following is a summary of the costs incurred, whether capitalized or
expensed, related to the Partnership's oil and gas producing activities for the
years ended December 31:




                                                2000         1999           1998
                                             ---------     --------      ---------

                                                                
     Development costs                       $  7,183      $  4,254      $  8,322
                                             =========     ========      =========

     Capitalized oil and gas properties consist of the following:




                                                          2000           1999
                                                      ----------      ----------
                                                              
     Proved properties:
       Property acquisition costs                    $   210,548     $   210,548
       Completed wells and equipment                   5,134,748       5,127,565
                                                      ----------      ----------

                                                       5,345,296       5,338,113
     Accumulated depletion                            (4,821,914)     (4,776,074)



       Net oil and gas properties                    $   523,382    $    562,039
                                                      ==========      ==========






                                       9
   180



NOTE 6.     RELATED PARTY TRANSACTIONS

     Pursuant to the limited partnership agreement, the Partnership had the
following related party transactions with the managing general partner during
the years ended December 31:




                                                         2000          1999            1998
                                                       --------      --------        --------
                                                                           
    Payment of lease operating and supervision
     charges in accordance with standard industry
     operating agreements                              $ 75,129      $ 61,684        $ 82,817

    Reimbursement of general and administrative
     expenses                                          $ 11,615      $  6,142        $  6,273


     Pioneer USA, EMPL and the Partnership are parties to the Partnership
agreement. EMPL is a limited partnership in which Pioneer USA owns 80% and the
remaining portion is owned by former affiliates.

     The costs and revenues of the Partnership are allocated as follows:




                                                         General       Limited
                                                         partners      partners
                                                         --------      --------
                                                                 
   Revenues:
     Proceeds from property dispositions prior to cost
      recovery                                              10%          90%
     All other Partnership revenues                         25%          75%
   Costs and expenses:
     Lease acquisition costs, drilling and completion
      costs and all other costs                             10%          90%
     Operating costs, direct costs and general and
      administrative expenses                               25%          75%


NOTE 7.     OIL AND GAS INFORMATION (UNAUDITED)

     The following table presents information relating to the Partnership's
estimated proved oil and gas reserves at December 31, 2000, 1999 and 1998 and
changes in such quantities during the years then ended. All of the Partnership's
reserves are proved developed and located within the United States. The
Partnership's reserves are based on an evaluation prepared by Williamson
Petroleum Consultants, Inc., an independent petroleum consultant, using criteria
established by the Securities and Exchange Commission.


                                       10
   181





                                                    Oil and NGLs          Gas
                                                       (bbls)            (mcf)
                                                    ------------      ------------

                                                                
    Net proved reserves at January 1, 1998            203,263            321,961
    Revisions                                         (93,478)          (131,045)
    Production                                        (16,033)           (22,439)
                                                    ---------         ----------

    Net proved reserves at December 31, 1998           93,752            168,477
    Revisions                                         118,281            224,790
    Production                                        (13,232)           (19,167)
                                                    ---------         ----------
    Net proved reserves at December 31, 1999          198,801            374,100
    Revisions                                          18,015            (61,237)
    Production                                        (13,921)           (15,864)
                                                    ---------         ----------
    Net proved reserves at December 31, 2000          202,895            296,999
                                                    =========         ==========


     As of December 31, 2000, the estimated present value of future net revenues
of proved reserves, calculated using December 31, 2000 prices of $26.64 per
barrel of oil, $14.08 per barrel of NGLs and $7.91 per mcf of gas, discounted at
10% was approximately $1,416,000 and undiscounted was $2,636,000.

     Numerous uncertainties exist in estimating quantities of proved reserves
and future net revenues therefrom. The estimates of proved reserves and related
future net revenues set forth in this Report are based on various assumptions,
which may ultimately prove to be inaccurate. Therefore, such estimates should
not be construed as estimates of the current market value of the Partnership's
proved reserves. The Partnership emphasizes that reserve estimates are
inherently imprecise and, accordingly, the estimates are expected to change as
future information becomes available.

Disclosures about Oil & Gas Producing Activities

Standardized Measure of Discounted Future Net Cash Flows

    The standardized measure of discounted future net cash flows is computed by
applying year-end prices of oil and gas (with consideration of price changes
only to the extent provided by contractual arrangements) to the estimated future
production of proved oil and gas reserves less estimated future expenditures
(based on year-end costs) to be incurred in developing and producing the proved
reserves, discounted using a rate of 10% per year to reflect the estimated
timing of the future cash flows. A Federal income tax provision has not been
calculated as the income of the Partnership is included in the individual
Federal income tax returns of the respective partners.

    Discounted future cash flow estimates like those shown below are not
intended to represent estimates of the fair value of oil and gas properties.
Estimates of fair value should also consider anticipated future oil and gas
prices, interest rates, changes in development and production costs and risks
associated with future production. Because of these and other considerations,
any estimate of fair value is necessarily subjective and imprecise.









                                       11
   182





                                              For the years ended December 31,
                                              --------------------------------

                                                2000        1999       1998
                                              ---------  ----------  ---------
                                                      (in thousands)
                                                           
Oil and gas producing activities:
  Future cash inflows                         $  6,624   $   4,915   $  1,020
  Future production costs                       (3,988)     (3,116)      (849)
                                              --------   ---------   --------

                                                 2,636       1,799        171
  10% annual discount factor                    (1,220)       (799)       (47)
                                              --------   ---------   --------

  Standardized measure of discounted future
   net cash flows                             $  1,416   $   1,000   $    124
                                              ========   =========   ========







                                              For the years ended December 31,
                                              --------------------------------

                                                2000        1999       1998
                                              ---------  ----------  ---------
                                                      (in thousands)

                                                           
  Oil and Gas Producing Activities:
    Oil and gas sales, net of production costs  $ (197)  $    (64)  $     (35)
    Net changes in prices and production costs     530         471       (544)
    Revisions of previous quantity estimates        45         781        (94)
    Accretion of discount                          100          12         76
    Changes in production rates, timing and
      other                                        (62)       (324)       (40)
                                              --------   ---------   --------
    Change in present value of future net
      revenues                                     416         876       (637)
                                              --------   ---------   --------
    Balance, beginning of year                   1,000         124        761
                                                ------     -------     ------

    Balance, end of year                      $  1,416   $   1,000   $    124
                                               =======    ========    =======




NOTE 8.    MAJOR CUSTOMERS

     The following table reflects the major customers of the Partnership's oil
and gas sales (a major customer is defined as a customer whose sales exceed 10%
of total sales) during the years ended December 31:




                                                2000       1999        1998
                                              --------   --------    --------

                                                            
            Plains Marketing, L.P.              56%         48%         -
            LG&E Natural Marketing, Inc.        13%         17%        19%
            NGTS LLC                            11%         14%         -
            Western Gas Processing               2%          4%        13%
            Genesis Crude Oil, L.P.              4%          1%        43%


     At December 31, 2000, the amounts receivable from Plains Marketing, L.P.,
LG&E Natural Marketing, Inc. and NGTS LLC were $26,794, $10,707 and $4,029,
respectively, which are included in the caption "Accounts receivable - oil and
gas sales" in the accompanying Balance Sheet.

     Pioneer USA is of the opinion that the loss of any one purchaser would not
have an adverse effect on the ability of the Partnership to sell its oil, NGLs
and gas production.


                                       12
   183



NOTE 9.     PARTNERSHIP AGREEMENT

     The following is a brief summary of the more significant provisions of the
limited partnership agreement:

     General partners - The general partners of the Partnership are Pioneer USA
     and EMPL. Pioneer USA, the managing general partner, has the power and
     authority to manage, control and administer all Partnership affairs. As
     managing general partner and operator of the Partnership's properties, all
     production expenses are incurred by Pioneer USA and billed to the
     Partnership. The majority of the Partnership's oil and gas revenues are
     received directly by the Partnership, however, a portion of the oil and gas
     revenue is initially received by Pioneer USA prior to being paid to the
     Partnership.

     Limited partner liability - The maximum amount of liability of any limited
     partner is the total contributions of such partner plus his share of any
     undistributed profits.

     Initial capital contributions - The limited partners entered into
     subscription agreements for aggregate capital contributions of $5,765,000.
     During 1983, the Partnership received a total of $675,000 from its limited
     partnership in response to an assessment by the managing general partner.
     The general partners are required to contribute amounts equal to 10% of
     Partnership expenditures for lease acquisition, drilling and completion and
     25% of direct, general and administrative and operating expenses.



                                       13
   184

                          PARKER & PARSLEY 81-II, LTD.
                          (A TEXAS LIMITED PARTNERSHIP)

THIS REPORT CONTAINS FORWARD LOOKING STATEMENTS THAT INVOLVE RISKS AND
UNCERTAINTIES. ACCORDINGLY, NO ASSURANCES CAN BE GIVEN THAT THE ACTUAL EVENTS
AND RESULTS WILL NOT BE MATERIALLY DIFFERENT THAN THE ANTICIPATED RESULTS
DESCRIBED IN THE FORWARD LOOKING STATEMENTS.

MANAGEMENT'S DISCUSSION AND ANALYSIS OF FINANCIAL CONDITION AND
  RESULTS OF OPERATIONS

Results of operations

2000 compared to 1999

The Partnership's oil and gas revenues increased 89% to $387,180 for 2000 as
compared to $204,717 in 1999. The increase in revenues resulted from higher
average prices received and a slight increase in production. In 2000, 8,885
barrels of oil, 5,036 barrels of natural gas liquids ("NGLs") and 15,864 mcf of
gas were sold, or 16,565 barrel of oil equivalents ("BOEs"). In 1999, 6,860
barrels of oil, 6,372 barrels of NGLs and 19,167 mcf of gas were sold, or 16,427
BOEs. Due to the decline characteristics of the Partnership's oil and gas
properties, management expects a certain amount of decline in production in the
future until the Partnership's economically recoverable reserves are fully
depleted.

The average price received per barrel of oil increased $12.59, or 76%, from
$16.67 in 1999 to $29.26 in 2000. The average price received per barrel of NGLs
increased $6.89, or 79%, from $8.70 in 1999 to $15.59 in 2000. The average price
received per mcf of gas increased 69% from $1.82 in 1999 to $3.07 in 2000. The
market price for oil and gas has been extremely volatile in the past decade, and
management expects a certain amount of volatility to continue in the foreseeable
future. The Partnership may therefore sell its future oil and gas production at
average prices lower or higher than that received in 2000.

Gain on disposition of assets of $240 was recognized during 1999 from equipment
credits received on one fully depleted well.

Total costs and expenses increased in 2000 to $249,395 as compared to $200,120
in 1999, an increase of $49,275, or 25%. The increase was primarily due to
increases in production costs and general and administrative expenses ("G&A"),
offset by a decline in depletion.

Production costs were $189,764 in 2000 and $140,847 in 1999, resulting in a
$48,917 increase, or 35%. The increase was primarily due to additional well
maintenance costs incurred to stimulate well production and higher production
taxes associated with higher oil and gas prices.

G&A's components are independent accounting and engineering fees and managing
general partner personnel and operating costs. During this period, G&A increased
40% from $9,864 in 1999 to $13,791 in 2000, primarily due to a higher percentage
of the managing general partner's G&A being allocated (limited to 3% of oil and
gas revenues) as a result of increased oil and gas revenues. The Partnership
paid the managing general partner $11,615 in 2000 and $6,142 in 1999 for G&A
incurred on behalf of the Partnership. The remaining G&A was paid directly by
the Partnership. The managing general partner determines the allocated expenses
based upon the level of activity of the Partnership relative to the
non-partnership activities of the managing general partner. The method of
allocation has been consistent over the past several years with certain
modifications incorporated to reflect changes in Pioneer USA's overall business
activities.

Depletion was $45,840 in 2000 as compared to $49,409 in 1999, representing a
decrease of $3,569, or 7%. This decrease was primarily due to an 18,828 barrels
of oil increase in proved reserves during 2000 as a result of higher commodity
prices, offset by an increase in oil production of 2,025 barrels for the period
ended December 31, 2000 compared to the same period in 1999.



   185


1999 compared to 1998

The Partnership's 1999 oil and gas revenues decreased 2% to $204,717 from
$209,110 in 1998. The decrease in revenues resulted from a decline in
production, offset by higher average prices received. In 1999, 6,860 barrels of
oil, 6,372 barrels of NGLs and 19,167 mcf of gas were sold, or 16,427 BOEs. In
1998, 9,451 barrels of oil, 6,582 barrels of NGLs and 22,439 mcf of gas were
sold, or 19,773 BOEs.

The average price received per barrel of oil increased $3.51, or 27%, from
$13.16 in 1998 to $16.67 in 1999. The average price received per barrel of NGLs
increased $1.97, or 29%, from $6.73 in 1998 to $8.70 in 1999. The average price
received per mcf of gas increased slightly from $1.80 in 1998 to $1.82 in 1999.

Gain on disposition of assets of $240 was recognized during 1999 from equipment
credits received on one fully depleted well.

Total costs and expenses decreased in 1999 to $200,120 as compared to $307,424
in 1998, a decrease of $107,304, or 35%. The decrease was primarily due to
declines in depletion, production costs and the impairment of oil and gas
properties, offset by an increase in G&A.

Production costs were $140,847 in 1999 and $173,960 in 1998, resulting in a
$33,113 decrease, or 19%. The decrease was due to declines in well maintenance
costs, ad valorem taxes and production taxes.

During this period, G&A increased 25% from $7,867 in 1998 to $9,864 in 1999
primarily due to a higher percentage of the managing general partner's G&A being
allocated (limited to 3% of oil and gas revenues) as a result of increased oil
and gas revenues. The Partnership paid the managing general partner $6,142 in
1999 and $6,273 in 1998 for G&A incurred on behalf of the Partnership.

In accordance with Statement of Financial Accounting Standards No. 121,
"Accounting for the Impairment of Long-Lived Assets and for Long-Lived Assets to
be Disposed Of" ("SFAS 121"), the managing general partner reviews the
Partnership's oil and gas properties for impairment whenever events or
circumstances indicate a decline in the recoverability of the carrying value of
the Partnership's assets may have occurred. As a result of the review and
evaluation of its long-lived assets for impairment, the Partnership recognized a
non-cash charge of $30,131 related to its oil and gas properties during 1998.

Depletion was $49,409 in 1999 compared to $95,466 in 1998, representing a
decrease of $46,057, or 48%. This decrease was the result of a combination of
factors that included an increase in proved reserves of 59,807 barrels of oil
during 1999 as a result of higher commodity prices, a decline in oil production
of 2,591 barrels for the period ended December 31, 1999 compared to the same
period in 1998 and a reduction in the Partnership's net depletable basis from
charges taken in accordance with SFAS 121 during the fourth quarter of 1998.

Petroleum Industry

The petroleum industry has been characterized by volatile oil, NGL and natural
gas commodity prices and relatively stable supplier costs during the three years
ended December 31, 2000. During 1998, weather patterns, regional economic
recessions and political matters combined to cause worldwide oil supplies to
exceed demand resulting in a substantial decline in oil prices. Also during
1998, but to a lesser extent, market prices for natural gas declined. During
1999 and 2000, the Organization of Petroleum Exporting Countries ("OPEC") and
certain other crude oil exporting nations announced reductions in their planned
export volumes. Those announcements, together with the enactment of the
announced reductions in export volumes, had a positive impact on world oil
prices, as have overall natural gas supply and demand fundamentals on North
American natural gas prices. Although the favorable commodity price environment
and stable field service cost environment is expected to continue during 2001,
there is no assurance that commodity prices will not return to a less favorable
level or that field service costs will not escalate in the future, both of which
could negatively impact the Partnership's future results of operations and cash
distributions.




   186


Liquidity and capital resources

Net Cash Provided by Operating Activities

Net cash provided by operating activities increased $93,061 during the year
ended December 31, 2000 from 1999. This increase was due to increases in oil and
gas sales receipts of $183,843, offset by increases in production costs paid of
$48,917, G&A expenses paid of $3,927 and working capital of $37,938. The
increase in oil and gas receipts resulted from the increase in commodity prices
during 2000 which contributed an additional $65,846 to oil and gas receipts and
$117,997 resulted from an increase in production during 2000. The increase in
production costs was primarily due to increased production taxes associated with
higher oil and gas prices and well maintenance costs incurred to stimulate well
production. The increase in G&A was primarily due to higher percentage of the
managing general partner's G&A being allocated (limited to 3% of oil and gas
revenues) as a result of increased oil and gas revenues.

Net Cash Used in Investing Activities

The Partnership's principal investing activities during 2000 and 1999 included
expenditures related to upgrades of equipment on various oil and gas properties.

Proceeds from asset dispositions of $690 were received during 1999 for the sale
of equipment on active properties.

Net Cash Used in Financing Activities

In 2000, cash distributions to the partners were $141,760, of which $38,944 was
distributed to the general partners and $102,816 to the limited partners. In
1999, cash distributions to the partners were $36,945, of which $9,080 was
distributed to the general partners and $27,865 to the limited partners.











   187


                          PARKER & PARSLEY 81-II, LTD.


SELECTED FINANCIAL DATA

The following selected financial data for the Partnership should be read in
connection with Management's Discussion and Analysis of Financial Condition and
Results of Operations and the financial statements included in the attached
supplemental information.



                                        Three months
                                            ended
                                          March 31,                       Years ended December 31,
                                   ---------------------   --------------------------------------------------------------
                                     2001        2000         2000         1999         1998         1997         1996
                                   --------   ----------   ----------   ----------   ----------   ----------   ----------
                                                                                          
  Oil and gas sales                $          $   70,001   $  387,180   $  204,717   $  209,110   $  311,922   $  363,398
                                   ========   ==========   ==========   ==========   ==========   ==========   ==========

  Impairment of oil and
    gas properties                 $          $       --   $       --   $       --   $   30,131   $   52,269   $       --
                                   ========   ==========   ==========   ==========   ==========   ==========   ==========

  Gain on litigation
      settlement, net              $          $       --   $       --   $       --   $       --   $       --   $    3,289
                                   ========   ==========   ==========   ==========   ==========   ==========   ==========

  Net income (loss)                $          $    7,922   $  140,560   $    6,232   $  (96,589)  $    9,511   $  113,519
                                   ========   ==========   ==========   ==========   ==========   ==========   ==========

  Allocation of net
    income (loss):
         Managing general
           partner                 $          $    3,743   $   41,791   $    8,423   $   (5,308)  $   24,620   $   37,637
                                   ========   ==========   ==========   ==========   ==========   ==========   ==========

         Limited partners          $          $    4,179   $   98,769   $   (2,191)  $  (91,281)  $  (15,109)  $   75,882
                                   ========   ==========   ==========   ==========   ==========   ==========   ==========

  Limited partners' net
    income (loss) per limited
    partnership interest           $          $     3.62   $    85.66   $    (1.90)  $   (79.17)  $   (13.10)  $    65.81
                                   ========   ==========   ==========   ==========   ==========   ==========   ==========

  Limited partners' cash
    distributions per limited
    partnership interest           $          $    11.23   $    89.17   $    24.17   $    29.68   $    93.49   $    89.30(a)
                                   ========   ==========   ==========   ==========   ==========   ==========   ==========

At year end:
  Total assets                     $          $  611,605   $  617,579   $  620,107   $  647,798   $  793,920   $  928,791
                                   ========   ==========   ==========   ==========   ==========   ==========   ==========


----------

(a)  Including litigation settlement per limited partnership interest of $2.85
     in 1996.


   188

                       PIONEER NATURAL RESOURCES COMPANY
                      PIONEER NATURAL RESOURCES USA, INC.
                           1400 WILLIAMS SQUARE WEST
                           5205 NORTH O'CONNOR BLVD.
                              IRVING, TEXAS 75039

                            SUPPLEMENTAL INFORMATION

                                       OF

            PARKER & PARSLEY 82-I, LTD., A TEXAS LIMITED PARTNERSHIP

                                       TO

                  PROXY STATEMENT/PROSPECTUS DATED      , 2001

                                   ----------

                  THE DATE OF THIS SUPPLEMENT IS       , 2001

                                   ----------

     This document contains important information specific to Parker & Parsley
82-I, Ltd. and supplements the proxy statement/prospectus dated      , 2001, of
Pioneer Natural Resources Company and Pioneer Natural Resources USA, Inc., by
which Pioneer USA is soliciting proxies to be voted at a special meeting of
limited partners of the partnership. The purpose of the special meeting is for
you to vote upon the merger of the partnership with and into Pioneer USA that,
if completed, will result in your receiving common stock of Pioneer Natural
Resources Company and cash for your partnership interests.

     This document contains the following information concerning Parker &
Parsley 82-I, Ltd.:

     o    A table containing:

          --   the aggregate initial investment by the limited partners

          --   the aggregate historical limited partner distributions through
               March 31, 2001

          --   the aggregate merger value attributable to partnership interests
               of limited partners, excluding Pioneer USA

          --   the merger value per $1,000 limited partner investment as of
               March 31, 2001

          --   the merger value per $1,000 limited partner investment as a
               multiple of distributions for the 12 months ended March 31, 2001

          --   the book value per $1,000 limited partner investment as of March
               31, 2001 and as of December 31, 2000

          --   the going concern value per $1,000 limited partner investment as
               of March 31, 2001

          --   the liquidation value per $1,000 limited partner investment as of
               March 31, 2001

          --   the ordinary tax loss per $1,000 limited partner investment in
               year of initial investment

     o    Information about the legal opinion for the limited partners

     o    The partnership's quarterly report on Form 10-Q, including
          management's discussion and analysis of financial condition and
          results of operations, for the three months ended March 31, 2001

     o    The partnership's annual report on Form 10-K, including management's
          discussion and analysis of financial condition and results of
          operations, for the year ended December 31, 2000

     o    Selected historical financial data for the partnership for the three
          months ended March 31, 2001 and 2000 and the five years ended December
          31, 2000


                                      -1-
   189



                           PARKER & PARSLEY 82-I, LTD.

                         SUPPLEMENTAL INFORMATION TABLE



                                                                                            
Aggregate Initial Investment by the Limited Partners(a)                                        $  11,805

Aggregate Historical Limited Partner Distributions through March 31, 2001(a)                   $  11,456

Aggregate Merger Value Attributable to Partnership Interests of Limited Partners,              $     863
Excluding Pioneer USA(a)

Merger Value per $1,000 Limited Partner Investment as of March 31, 2001(b)                     $   81.87

Merger Value per $1,000 Limited Partner Investment as a Multiple of Distributions for the           3.75 times
12 Months ended March 31, 2001(b)

Book Value per $1,000 Limited Partner Investment:

          --   as of March 31, 2001(b)                                                         $

          --   as of December 31, 2000(b)                                                      $   23.71

Going Concern Value per $1,000 Limited Partner Investment as of March 31, 2001(b)              $   72.47

Liquidation Value per $1,000 Limited Partner Investment as of March 31, 2001(b)                $   79.73

Ordinary Tax Loss per $1,000 Limited Partner Investment in Year of Initial Investment          $     265
(b), (c)




----------

(a)  Stated in thousands.

(b)  Interests in some partnerships were sold in units at prices other than
     $1,000. We have presented this information based on a $1,000 initial
     investment for ease of use and comparison among partnerships. You should
     not assume that the amount shown per $1,000 investment is the same as the
     value or amount attributable to a single unit investment.

(c)  Your ability to use your distributive share of the partnership's loss to
     offset your other income may have been subject to certain limitations at
     your level as a partner, and you may therefore wish to consult your tax
     advisor to determine the additional value, if any, actually realized by you
     in your particular circumstances.



          INFORMATION ABOUT THE LEGAL OPINION FOR THE LIMITED PARTNERS

     The partnership agreement for the partnership requires that special legal
counsel render an opinion on behalf of the limited partners to Pioneer USA that
(1) neither the grant nor the exercise of the right to approve the merger of the
partnership by its limited partners will adversely affect the federal income tax
classification of the partnership or any of its limited partners; and (2)
neither the grant nor exercise of such right will result in the loss of any
limited partner's limited liability. In addition, the counsel designated to
render the opinion must be counsel other than counsel to Pioneer USA or the
partnership. Both the designated counsel and the legal opinion must be approved
by the limited partners. Pioneer USA has retained __________ of Dallas, Texas
for the purpose of rendering this legal opinion on behalf of the limited
partners to Pioneer USA. The merger proposals include an approval of that
counsel and the form of its opinion. A copy of the opinion is attached as an
exhibit to the merger proposals.


                                      -2-
   190
                UNITED STATES SECURITIES AND EXCHANGE COMMISSION
                             WASHINGTON, D. C. 20549

                                    FORM 10-K

                  Annual Report Pursuant to Section 13 or 15(d)
                     of the Securities Exchange Act of 1934

                   FOR THE FISCAL YEAR ENDED DECEMBER 31, 2000


                          COMMISSION FILE NO. 2-75530A


                           PARKER & PARSLEY 82-I, LTD.
             (Exact name of Registrant as specified in its charter)


                     TEXAS                             75-1825545
        -------------------------------         ----------------------
        (State or other jurisdiction of            (I.R.S. Employer
        incorporation or organization)          Identification Number)


1400 WILLIAMS SQUARE WEST, 5205 N. O'CONNOR BLVD., IRVING, TEXAS        75039
----------------------------------------------------------------      ----------
           (Address of principal executive offices)                   (Zip code)

       Registrant's Telephone Number, including area code: (972) 444-9001

        Securities registered pursuant to Section 12(b) of the Act: NONE
          Securities registered pursuant to Section 12(g) of the Act:
                 LIMITED PARTNERSHIP INTERESTS ($2,000 PER UNIT)
                 -----------------------------------------------

Indicate by check mark whether the Registrant (1) has filed all reports required
to be filed by Section 13 or 15(d) of the Securities Exchange Act of 1934 during
the preceding 12 months (or for such shorter period that the Registrant was
required to file such reports), and (2) has been subject to such filing
requirements for the past 90 days. YES / X / NO / /

Indicate by check mark if disclosure of delinquent filers pursuant to Item 405
of Regulation S-K is not contained herein, and will not be contained, to the
best of Registrant's knowledge, in definitive proxy or information statements
incorporated by reference in Part III of this Form 10-K or any amendment to this
Form 10-K. / X /

No market currently exists for the limited partnership interests of the
Registrant. Based on the original purchase price, the aggregate market value of
limited partnership interests owned by non-affiliates of the Registrant is
$8,515,000.

       As of March 8, 2001, the number of outstanding limited partnership
                              interests was 4,891.

 The following documents are incorporated by reference into the indicated parts
                    of this Annual Report on Form 10-K: None

PARTS I AND II OF THIS ANNUAL REPORT ON FORM 10-K (THE "REPORT") CONTAIN FORWARD
LOOKING STATEMENTS THAT INVOLVE RISKS AND UNCERTAINTIES. ACCORDINGLY, NO
ASSURANCES CAN BE GIVEN THAT THE ACTUAL EVENTS AND RESULTS WILL NOT BE
MATERIALLY DIFFERENT THAN THE ANTICIPATED RESULTS DESCRIBED IN THE FORWARD
LOOKING STATEMENTS. SEE "ITEM 1. BUSINESS" FOR A DESCRIPTION OF VARIOUS FACTORS
THAT COULD MATERIALLY AFFECT THE ABILITY OF THE PARTNERSHIP TO ACHIEVE THE
ANTICIPATED RESULTS DESCRIBED IN THE FORWARD LOOKING STATEMENTS.

   191

                                     PART I

ITEM 1.  BUSINESS

Parker & Parsley 82-I, Ltd. (the "Partnership") is a limited partnership
organized in 1982 under the laws of the State of Texas. The Partnership's
managing general partner is Pioneer Natural Resources USA, Inc. ("Pioneer USA")
and its co-general partner is P&P Employees 82-I, Ltd. ("EMPL"), a Texas limited
partnership whose general partner is Pioneer USA. Pioneer USA is a wholly-owned
subsidiary of Pioneer Natural Resources Company ("Pioneer"). As of March 8,
2001, the Partnership had 4,891 limited partnership interests outstanding.

The Partnership does not have any employees of its own. Pioneer USA employs 701
persons, many of whom dedicated a part of their time to the conduct of the
Partnership's business during the period for which this Report is filed. Pioneer
USA supplies all management functions.

The Partnership engages in oil and gas development and production and is not
involved in any industry segment other than oil and gas. The Partnership's
production is geographically concentrated in West Texas.

The principal markets during 2000 for the oil produced by the Partnership were
refineries and oil transmission companies that have facilities near the
Partnership's oil producing properties. During 2000, Pioneer USA marketed the
Partnership's gas to a variety of purchasers. Of the Partnership's total oil and
gas revenues for 2000, approximately 68% and 13% were attributable to sales made
to Plains Marketing, L.P. and GPM Gas Corporation, respectively. Pioneer USA is
of the opinion that the loss of any one purchaser would not have an adverse
effect on its ability to sell its oil, natural gas liquids ("NGLs") and gas
production.

The Partnership's revenues, profitability, cash flow and future rate of growth
are highly dependent on the prevailing prices of oil and gas, which are affected
by numerous factors beyond the Partnership's control. Oil and gas prices
historically have been very volatile. A substantial or extended decline in the
prices of oil or gas could have a material adverse effect on the Partnership's
revenues, profitability and cash flow and could, under certain circumstances,
result in a reduction in the carrying value of the Partnership's oil and gas
properties.

Oil and gas production operations are subject to various types of regulations by
local, state and federal agencies. The Partnership's operations are also subject
to state conservation laws and regulations, including the establishment of
maximum rates of production from wells and the regulation of spacing, plugging
and abandonment of wells. Each state generally imposes a production or severance
tax with respect to production and sale of oil and gas within their respective
jurisdictions. Noncompliance with the laws and regulations may subject the
Partnership to penalties, damages or other liabilities and compliance may
increase the cost of the Partnership's operations.


                                       2
   192

The oil and gas business is also subject to environmental hazards such as oil
spills, gas leaks and ruptures and discharges of toxic substances or gases that
could expose the Partnership to substantial liability due to pollution and other
environmental damages. Although the Partnership believes that its business
operations do not impair environmental quality and that its costs of complying
with any applicable environmental regulations are not currently significant, the
Partnership cannot predict what, if any, effect these environmental regulations
may have on its current or future operations.

Numerous uncertainties exist in estimating quantities of proved reserves and
future net revenues therefrom. The estimates of proved reserves and related
future net revenues set forth in this Report are based on various assumptions,
which may ultimately prove to be inaccurate. Therefore, such estimates should
not be construed as estimates of the current market value of the Partnership's
proved reserves.

No material part of the Partnership's business is seasonal and the Partnership
conducts no foreign operations.

ITEM 2.  PROPERTIES

The Partnership's properties consist of leasehold interests in properties on
which oil and gas wells are located. Such property interests are often subject
to landowner royalties, overriding royalties and other oil and gas leasehold
interests.

Fractional working interests in developmental and exploratory oil and gas
prospects located in Texas and New Mexico were acquired by the Partnership,
resulting in the Partnership's participation in the drilling of 34 oil and gas
wells. There were six dry holes from previous periods, two wells plugged and
abandoned and nine wells sold. At December 31, 2000, 17 wells were producing.

For information relating to the Partnership's estimated proved oil and gas
reserves at December 31, 2000, 1999 and 1998 and changes in such quantities for
the years then ended, see Note 7 of Notes to Financial Statements included in
"Item 8. Financial Statements and Supplementary Data" below. Such reserves have
been evaluated by Williamson Petroleum Consultants, Inc., an independent
petroleum consultant.

ITEM 3.  LEGAL PROCEEDINGS

The Partnership from time to time is a party to various legal proceedings
incidental to its business involving claims in oil and gas leases or interests,
other claims for damages in amounts not in excess of 10% of its current assets
and other matters, none of which Pioneer USA believes to be material to the
Partnership.

ITEM 4.  SUBMISSION OF MATTERS TO A VOTE OF SECURITY HOLDERS

There were no matters submitted to a vote of the partners during the fourth
quarter of 2000.


                                       3
   193

                                     PART II

ITEM 5.  MARKET FOR LIMITED PARTNERSHIP INTERESTS AND LIMITED PARTNERSHIP
           DISTRIBUTIONS

At March 8, 2001, the Partnership had 4,891 outstanding limited partnership
interests held of record by 600 subscribers. There is no established public
trading market for the limited partnership interests. Under the limited
partnership agreement, Pioneer USA has made certain commitments to purchase
partnership interests at a computed value.

Revenues which, in the sole judgement of the managing general partner, are not
required to meet the Partnership's obligations are distributed to the partners
at least quarterly in accordance with the limited partnership agreement. During
the years ended December 31, 2000 and 1999, distributions of $229,765 and
$50,502, respectively, were made to the limited partners.

ITEM 6.  SELECTED FINANCIAL DATA

The following table sets forth selected financial data for the years ended
December 31:



                                   2000           1999           1998           1997         1996
                               ------------   ------------   ------------   ------------   ----------
                                                                            
Operating results:
-----------------
 Oil and gas sales             $    763,858   $    441,997   $    392,883   $    608,207   $  710,173
                               ============   ============   ============   ============   ==========

 Gain on litigation
   settlement, net             $         --   $         --   $         --   $         --   $   43,618
                               ============   ============   ============   ============   ==========

 Impairment of oil and gas
   properties                  $         --   $         --   $    294,610   $    165,201   $    2,277
                               ============   ============   ============   ============   ==========

 Net income (loss)             $    337,729   $     17,320   $   (563,993)  $    (60,847)  $  312,582
                               ============   ============   ============   ============   ==========

 Allocation of net income
   (loss):
     General partners          $     88,128   $     18,135   $    (49,472)  $     31,736   $   92,811
                               ============   ============   ============   ============   ==========

     Limited partners          $    249,601   $       (815)  $   (514,521)  $    (92,583)  $  219,771
                               ============   ============   ============   ============   ==========

 Limited partners' net
   income (loss) per limited
   partnership interest        $      51.03   $       (.17)  $    (105.20)  $     (18.93)  $    44.93
                               ============   ============   ============   ============   ==========

 Limited partners' cash
   distributions per limited
   partnership interest        $      46.98   $      10.33   $      19.57   $      47.31   $    51.40(a)
                               ============   ============   ============   ============   ==========

At year end:
-----------
 Identifiable assets           $    454,904   $    425,107   $    474,528   $  1,158,135   $1,526,765
                               ============   ============   ============   ============   ==========


---------------

(a) Including litigation settlement per limited partnership interest of $6.96 in
    1996.


                                       4
   194

ITEM 7.  MANAGEMENT'S DISCUSSION AND ANALYSIS OF FINANCIAL CONDITION AND RESULTS
           OF OPERATIONS

Results of operations

2000 compared to 1999

The Partnership's oil and gas revenues increased 73% to $763,858 for 2000 as
compared to $441,997 in 1999. The increase in revenues resulted from higher
average prices received, offset by a decline in production. In 2000, 17,639
barrels of oil, 6,519 barrels of natural gas liquids ("NGLs") and 45,981 mcf of
gas were sold, or 31,822 barrel of oil equivalents ("BOEs"). In 1999, 17,472
barrels of oil, 6,414 barrels of NGLs and 48,380 mcf of gas were sold, or 31,949
BOEs. Due to the decline characteristics of the Partnership's oil and gas
properties, management expects a certain amount of decline in production in the
future until the Partnership's economically recoverable reserves are fully
depleted.

The average price received per barrel of oil increased $12.78, or 77%, from
$16.61 in 1999 to $29.39 in 2000. The average price received per barrel of NGLs
increased $5.48, or 61%, from $8.96 in 1999 to $14.44 in 2000. The average price
received per mcf of gas increased 69% from $1.95 in 1999 to $3.29 in 2000. The
market price for oil and gas has been extremely volatile in the past decade and
management expects a certain amount of volatility to continue in the foreseeable
future. The Partnership may therefore sell its future oil and gas production at
average prices lower or higher than that received in 2000.

Total costs and expenses increased in 2000 to $431,421 as compared to $427,526
in 1999, an increase of $3,895, or 1%. The increase was due to increases in
production costs and general and administrative expenses ("G&A"), offset by a
decline in depletion.

Production costs were $378,872 in 2000 and $313,158 in 1999, resulting in an
increase of $65,714, or 21%. The increase was primarily due to additional well
maintenance costs incurred to stimulate well production and higher production
taxes associated with higher oil and gas prices.

G&A's components are independent accounting and engineering fees and managing
general partner personnel and operating costs. During this period, G&A increased
39% from $18,932 in 1999 to $26,409 in 2000 primarily due to a higher percentage
of the managing general partner's G&A being allocated (limited to 3% of oil and
gas revenues) as a result of increased oil and gas revenues. The Partnership
paid the managing general partner $22,916 in 2000 and $13,260 in 1999 for G&A
incurred on behalf of the Partnership. The remaining G&A was paid directly by
the Partnership. The managing general partner determines the allocated expenses
based upon the level of activity of the Partnership relative to the
non-partnership activities of the managing general partner. The method of
allocation has been consistent over the past several years with certain
modifications incorporated to reflect changes in Pioneer USA's overall business
activities.

Depletion was $26,140 in 2000 as compared to $95,436 in 1999, representing a
decrease of $69,296, or 73%. This decrease was primarily due to a 86,555 barrels
of oil increase in proved reserves during 2000 as a result of higher commodity
prices.

1999 compared to 1998

The Partnership's 1999 oil and gas revenues increased 13% to $441,997 from
$392,883 in 1998. The increase in revenues resulted from higher average prices
received, offset by a decline in production. In 1999, 17,472 barrels of oil,
6,414 barrels of NGLs and 48,380 mcf of gas were sold, or 31,949 BOEs. In 1998,
19,150 barrels of oil, 6,748 barrels of NGLs and 48,971 mcf of gas were sold, or
34,060 BOEs.


                                       5
   195

The average price received per barrel of oil increased $3.29, or 25%, from
$13.32 in 1998 to $16.61 in 1999. The average price received per barrel of NGLs
increased $1.76, or 24%, from $7.20 in 1998 to $8.96 in 1999. The average price
received per mcf of gas increased 7% from $1.82 in 1998 to $1.95 in 1999.

A gain on disposition of assets of $199 was recognized during 1998 from post
closing adjustments received from the sale of eight oil and gas wells during
1997.

Total costs and expenses decreased in 1999 to $427,526 as compared to $961,319
in 1998, a decrease of $533,793, or 56%. The decrease was primarily due to
declines in the impairment of oil and gas properties, depletion and production
costs, offset by an increase in G&A expenses.

Production costs were $313,158 in 1999 and $336,406 in 1998, resulting in a
$23,248 decrease, or 7%. The decrease was due to declines in well maintenance
costs and ad valorem taxes.

During this period, G&A increased 30% from $14,542 in 1998 to $18,932 in 1999
primarily due to a higher percentage of the managing general partner's G&A being
allocated (limited to 3% of oil and gas revenues) as a result of increased oil
and gas revenues. The Partnership paid the managing general partner $13,260 in
1999 and $11,786 in 1998 for G&A incurred on behalf of the Partnership.

In accordance with Statement of Financial Accounting Standards No. 121,
"Accounting for the Impairment of Long-Lived Assets and for Long-Lived Assets to
be Disposed Of" ("SFAS 121"), the managing general partner reviews the
Partnership's oil and gas properties for impairment whenever events or
circumstances indicate a decline in the recoverability of the carrying value of
the Partnership's assets may have occurred. As a result of the review and
evaluation of its long-lived assets for impairment, the Partnership recognized a
non-cash charge of $294,610 related to its oil and gas properties during 1998.

Depletion was $95,436 in 1999 compared to $315,761 in 1998, representing a
decrease of $220,325, or 70%. This decrease was the result of an increase in
proved reserves of 168,752 barrels of oil during 1999 as a result of higher
commodity prices and a reduction in the Partnership's net depletable basis from
charges taken in accordance with SFAS 121 during the fourth quarter of 1998.


Petroleum industry

The petroleum industry has been characterized by volatile oil, NGL and natural
gas commodity prices and relatively stable supplier costs during the three years
ended December 31, 2000. During 1998, weather patterns, regional economic
recessions and political matters combined to cause worldwide oil supplies to
exceed demand resulting in a substantial decline in oil prices. Also during
1998, but to a lesser extent, market prices for natural gas declined. During
1999 and 2000, the Organization of Petroleum Exporting Countries ("OPEC") and
certain other crude oil exporting nations announced reductions in their planned
export volumes. Those announcements, together with the enactment of the
announced reductions in export volumes, had a positive impact


                                       6
   196

on world oil prices, as have overall natural gas supply and demand fundamentals
on North American natural gas prices. Although the favorable commodity price
environment and stable field service cost environment is expected to continue
during 2001, there is no assurance that commodity prices will not return to a
less favorable level or that field service costs will not escalate in the
future, both of which could negatively impact the Partnership's future results
of operations and cash distributions.

Liquidity and capital resources

Net Cash Provided by Operating Activities

Net cash provided by operating activities increased $227,133 during the year
ended December 31, 2000 from 1999. This increase was due to an increase in oil
and gas sales receipts of $324,304, offset by increases in production costs paid
of $65,714, G&A expenses paid of $7,477 and working capital of $23,980. The
increase in oil and gas receipts resulted from the increase in commodity prices
during 2000 which contributed an additional $325,772 to oil and gas receipts,
offset by $1,468 resulting from the decline in production during 2000. The
increase in production costs was primarily due to increased production taxes
associated with higher oil and gas prices and well maintenance costs incurred to
stimulate well production. The increase in G&A was primarily due to higher
percentage of the managing general partner's G&A being allocated (limited to 3%
of oil and gas revenues) as a result of increased oil and gas revenues.

Net Cash Provided by (Used in) Investing Activities

The Partnership's principle investing activities during 2000 and 1999 were
related to the upgrades of oil and gas equipment on various oil and gas
properties.

Proceeds from asset dispositions of $704 in 1999 were from equipment credits
received on active properties.

Net Cash Used in Financing Activities

In 2000, cash distributions to the partners were $308,330, of which $78,565 was
distributed to the general partners and $229,765 to the limited partners. In
1999, cash distributions to the partners were $67,767, of which $17,265 was
distributed to the general partners and $50,502 to the limited partners.


                                       7
   197

ITEM 8.  FINANCIAL STATEMENTS AND SUPPLEMENTARY DATA


                          INDEX TO FINANCIAL STATEMENTS



                                                                         Page
                                                                         ----
                                                                      
Financial Statements of Parker & Parsley 82-I, Ltd:
 Independent Auditors' Report............................................  9
 Balance Sheets as of December 31, 2000 and 1999......................... 10
 Statements of Operations for the Years Ended December 31,
   2000, 1999 and 1998................................................... 11
 Statements of Partners' Capital for the Years Ended
   December 31, 2000, 1999 and 1998...................................... 12
 Statements of Cash Flows for the Years Ended December 31,
   2000, 1999 and 1998................................................... 13
 Notes to Financial Statements........................................... 14



                                       8
   198

                          INDEPENDENT AUDITORS' REPORT



The Partners
Parker & Parsley 82-I, Ltd.
(A Texas Limited Partnership):

We have audited the balance sheets of Parker & Parsley 82-I, Ltd. as of December
31, 2000 and 1999, and the related statements of operations, partners' capital
and cash flows for each of the three years in the period ended December 31,
2000. These financial statements are the responsibility of the Partnership's
management. Our responsibility is to express an opinion on these financial
statements based on our audits.

We conducted our audits in accordance with auditing standards generally accepted
in the United States. Those standards require that we plan and perform the audit
to obtain reasonable assurance about whether the financial statements are free
of material misstatement. An audit includes examining, on a test basis, evidence
supporting the amounts and disclosures in the financial statements. An audit
also includes assessing the accounting principles used and significant estimates
made by management, as well as evaluating the overall financial statement
presentation. We believe that our audits provide a reasonable basis for our
opinion.

In our opinion, the financial statements referred to above present fairly, in
all material respects, the financial position of Parker & Parsley 82-I, Ltd. as
of December 31, 2000 and 1999, and the results of its operations and its cash
flows for each of the three years in the period ended December 31, 2000, in
conformity with accounting principles generally accepted in the United States.



                                                     Ernst & Young LLP


Dallas, Texas
March 9, 2001


                                       9
   199

                           PARKER & PARSLEY 82-I, LTD.
                          (A Texas Limited Partnership)

                                 BALANCE SHEETS
                                   December 31




                                                     2000           1999
                                                 -----------    -----------
                                                          
              ASSETS
              ------

Current assets:
 Cash                                            $    57,728    $    61,558
 Accounts receivable - oil and gas sales             109,719         61,533
                                                 -----------    -----------

       Total current assets                          167,447        123,091
                                                 -----------    -----------

Oil and gas properties - at cost, based on the
 successful efforts accounting method              9,901,101      9,889,520
Accumulated depletion                             (9,613,644)    (9,587,504)
                                                 -----------    -----------

       Net oil and gas properties                    287,457        302,016
                                                 -----------    -----------

                                                 $   454,904    $   425,107
                                                 ===========    ===========

LIABILITIES AND PARTNERS' CAPITAL
---------------------------------

Current liabilities:
 Accounts payable - affiliate                    $    13,712    $    13,314

Partners' capital:
 General partners                                    161,365        151,802
 Limited partners (4,891 interests)                  279,827        259,991
                                                 -----------    -----------

                                                     441,192        411,793
                                                 -----------    -----------

                                                 $   454,904    $   425,107
                                                 ===========    ===========



   The accompanying notes are an integral part of these financial statements.


                                       10
   200

                           PARKER & PARSLEY 82-I, LTD.
                          (A Texas Limited Partnership)

                            STATEMENTS OF OPERATIONS
                         For the years ended December 31




                                               2000        1999         1998
                                            ---------   ---------    ---------
                                                            
Revenues:
  Oil and gas                               $ 763,858   $ 441,997    $ 392,883
  Interest                                      5,292       2,849        4,244
  Gain on disposition of assets                    --          --          199
                                            ---------   ---------    ---------

                                              769,150     444,846      397,326
                                            ---------   ---------    ---------

Costs and expenses:
  Oil and gas production                      378,872     313,158      336,406
  General and administrative                   26,409      18,932       14,542
  Impairment of oil and gas properties             --          --      294,610
  Depletion                                    26,140      95,436      315,761
                                            ---------   ---------    ---------

                                              431,421     427,526      961,319
                                            ---------   ---------    ---------

Net income (loss)                           $ 337,729   $  17,320    $(563,993)
                                            =========   =========    =========

Allocation of net income (loss):
  General partners                          $  88,128   $  18,135    $ (49,472)
                                            =========   =========    =========

  Limited partners                          $ 249,601   $    (815)   $(514,521)
                                            =========   =========    =========

Net income (loss) per limited partnership
  interest                                  $   51.03   $    (.17)   $ (105.20)
                                            =========   =========    =========



   The accompanying notes are an integral part of these financial statements.


                                       11
   201

                           PARKER & PARSLEY 82-I, LTD.
                          (A Texas Limited Partnership)

                         STATEMENTS OF PARTNERS' CAPITAL




                                            General          Limited
                                            partners         partners           Total
                                           -----------      -----------      -----------

                                                                    
Partners' capital at January 1, 1998       $   221,119      $   921,541      $ 1,142,660

  Distributions                                (20,715)         (95,712)        (116,427)

  Net loss                                     (49,472)        (514,521)        (563,993)
                                           -----------      -----------      -----------

Partners' capital at December 31, 1998         150,932          311,308          462,240

  Distributions                                (17,265)         (50,502)         (67,767)

  Net income (loss)                             18,135             (815)          17,320
                                           -----------      -----------      -----------

Partners' capital at December 31, 1999         151,802          259,991          411,793

  Distributions                                (78,565)        (229,765)        (308,330)

  Net income                                    88,128          249,601          337,729
                                           -----------      -----------      -----------

Partners' capital at December 31, 2000     $   161,365      $   279,827      $   441,192
                                           ===========      ===========      ===========



   The accompanying notes are an integral part of these financial statements.


                                       12
   202

                           PARKER & PARSLEY 82-I, LTD.
                          (A Texas Limited Partnership)

                            STATEMENTS OF CASH FLOWS
                         For the years ended December 31




                                                      2000          1999          1998
                                                    ---------     ---------     ---------
                                                                       
Cash flows from operating activities:
 Net income (loss)                                  $ 337,729     $  17,320     $(563,993)
 Adjustments to reconcile net income (loss) to
   net cash provided by operating activities:
     Impairment of oil and gas properties                  --            --       294,610
     Depletion                                         26,140        95,436       315,761
     Gain on disposition of assets                         --            --          (199)
 Changes in assets and liabilities:
   Accounts receivable                                (48,186)      (24,834)       26,999
   Accounts payable                                       398         1,026        (3,187)
                                                    ---------     ---------     ---------

       Net cash provided by operating activities      316,081        88,948        69,991
                                                    ---------     ---------     ---------

Cash flows from investing activities:
 Additions to oil and gas properties                  (11,581)       (4,754)       (6,820)
 Proceeds from asset dispositions                          --           704        14,397
                                                    ---------     ---------     ---------

       Net cash provided by (used in)
          investing activities                        (11,581)       (4,050)        7,577
                                                    ---------     ---------     ---------

Cash flows used in financing activities:
 Cash distributions to partners                      (308,330)      (67,767)     (116,427)
                                                    ---------     ---------     ---------

Net increase (decrease) in cash                        (3,830)       17,131       (38,859)
Cash at beginning of year                              61,558        44,427        83,286
                                                    ---------     ---------     ---------

Cash at end of year                                 $  57,728     $  61,558     $  44,427
                                                    =========     =========     =========



   The accompanying notes are an integral part of these financial statements.


                                       13
   203

                           PARKER & PARSLEY 82-I, LTD.
                          (A Texas Limited Partnership)

                          NOTES TO FINANCIAL STATEMENTS
                        December 31, 2000, 1999 and 1998


NOTE 1.  ORGANIZATION AND NATURE OF OPERATIONS

        Parker & Parsley 82-I, Ltd. (the "Partnership") is a limited partnership
organized in 1982 under the laws of the State of Texas. The Partnership's
general partners are Pioneer Natural Resources USA, Inc. ("Pioneer USA") and P&P
Employees 82-I, Ltd. ("EMPL"). The Partnership's managing general partner is
Pioneer USA.

        The Partnership engages in oil and gas development and production in
Texas and is not involved in any industry segment other than oil and gas.

NOTE 2.  SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES

        A summary of the significant accounting policies consistently applied in
the preparation of the accompanying financial statements follows:

        Oil and gas properties - The Partnership utilizes the successful efforts
method of accounting for its oil and gas properties and equipment. Under this
method, all costs associated with productive wells and nonproductive development
wells are capitalized while nonproductive exploration costs are expensed.
Capitalized costs relating to proved properties are depleted using the
unit-of-production method on a property-by-property basis based on proved oil
(dominant mineral) reserves as evaluated by independent petroleum consultants.
The carrying amounts of properties sold or otherwise disposed of and the related
allowances for depletion are eliminated from the accounts and any gain or loss
is included in results of operations.

        Impairment of long-lived assets - In accordance with Statement of
Financial Accounting Standards No. 121, "Accounting for the Impairment of
Long-Lived Assets and for Long-Lived Assets to be Disposed Of" ("SFAS 121"), the
Partnership reviews its long-lived assets to be held and used on an individual
property basis, including oil and gas properties accounted for under the
successful efforts method of accounting, whenever events or circumstances
indicate that the carrying value of those assets may not be recoverable. An
impairment loss is indicated if the sum of the expected future cash flows is
less than the carrying amount of the assets. In this circumstance, the
Partnership recognizes an impairment loss for the amount by which the carrying
amount of the asset exceeds the estimated fair value of the asset.

        Use of estimates in the preparation of financial statements -
Preparation of the accompanying financial statements in conformity with
generally accepted accounting principles requires management to make estimates
and assumptions that affect the reported amounts of assets and liabilities and
disclosure of contingent assets and liabilities at the date of the financial
statements and the reported amounts of revenues and expenses during the
reporting periods. Actual results could differ from those estimates.


                                       14
   204

        Net income (loss) per limited partnership interest - The net income
(loss) per limited partnership interest is calculated by using the number of
outstanding limited partnership interests.

        Income taxes - A Federal income tax provision has not been included in
the financial statements as the income of the Partnership is included in the
individual Federal income tax returns of the respective partners.

        Statements of cash flows - For purposes of reporting cash flows, cash
includes depository accounts held by banks.

        General and administrative expenses - General and administrative
expenses are allocated in part to the Partnership by the managing general
partner. Allocated expenses are determined by the managing general partner based
upon the level of activity of the Partnership relative to the non-partnership
activities of the managing general partner. The method of allocation has been
consistent over the past several years with certain modifications incorporated
to reflect changes in Pioneer USA's overall business activities.

        Reclassifications - Certain reclassifications may have been made to the
1999 and 1998 financial statements to conform to the 2000 financial statement
presentations.

        Environmental - The Partnership is subject to extensive federal, state
and local environmental laws and regulations. These laws, which are constantly
changing, regulate the discharge of materials into the environment and may
require the Partnership to remove or mitigate the environmental effects of the
disposal or release of petroleum or chemical substances at various sites.
Environmental expenditures are expensed or capitalized depending on their future
economic benefit. Expenditures that relate to an existing condition caused by
past operations and that have no future economic benefits are expensed.
Liabilities for expenditures of a noncapital nature are recorded when
environmental assessment and/or remediation is probable, and the costs can be
reasonably estimated. Such liabilities are generally undiscounted unless the
timing of cash payments for the liability or component are fixed or reliably
determinable. No such liabilities have been accrued as of December 31, 2000.

        Revenue recognition - The Partnership uses the entitlements method of
accounting for oil, natural gas liquids ("NGLs") and natural gas revenues.

NOTE 3.  IMPAIRMENT OF LONG-LIVED ASSETS

        In accordance with SFAS 121, the Partnership reviews its proved oil and
gas properties for impairment whenever events and circumstances indicate a
decline in the recoverability of the carrying value of the Partnership's oil and
gas properties. The Partnership has estimated the expected future cash flows of
its oil and gas properties as of December 31, 2000, 1999 and 1998, based on
proved reserves, and compared such estimated future cash flows to the respective
carrying amount of the oil and gas properties to determine if the carrying
amounts were likely to be recoverable. For those proved oil and gas properties
for which the carrying amount exceeded the estimated future cash flows, an
impairment was determined to exist; therefore, the Partnership adjusted the
carrying amount of those oil and gas properties to their fair value as
determined by discounting their expected future cash flows at a discount rate
commensurate with the risks involved in the industry. As a result, the
Partnership recognized a non-cash impairment provision of $294,610 related to
its proved oil and gas properties during 1998.


                                       15
   205

NOTE 4.  INCOME TAXES

        The financial statement basis of the Partnership's net assets and
liabilities was $663,714 less than the tax basis at December 31, 2000.

        The following is a reconciliation of net income (loss) per statements of
operations with the net income per Federal income tax returns for the years
ended December 31:



                                                         2000          1999         1998
                                                      ---------     ---------    ---------

                                                                        
Net income (loss) per statements of operations        $ 337,729     $  17,320    $(563,993)
Depletion and depreciation provisions for
 tax reporting purposes less than amounts for
 financial reporting purposes                            21,746        92,542      312,201
Impairment of oil and gas properties for financial
 reporting purposes                                          --            --      294,610
Loss on disposition of assets                                --            --         (116)
Other, net                                                 (637)           77          786
                                                      ---------     ---------    ---------
        Net income per Federal income tax
          returns                                     $ 358,838     $ 109,939    $  43,488
                                                      =========     =========    =========


NOTE 5.  OIL AND GAS PRODUCING ACTIVITIES

        The following is a summary of the costs incurred, whether capitalized or
expensed, related to the Partnership's oil and gas producing activities for the
years ended December 31:



                        2000         1999      1998
                     ---------    ---------    ------

                                      
Development costs    $  11,581    $   4,754    $6,820
                     =========    =========    ======


        Capitalized oil and gas properties consist of the following:



                                        2000            1999
                                    -----------     -----------
                                              
Proved properties:
 Property acquisition costs         $   360,899     $   360,899
 Completed wells and equipment        9,540,202       9,528,621
                                    -----------     -----------

                                      9,901,101       9,889,520
Accumulated depletion                (9,613,644)     (9,587,504)
                                    -----------     -----------

      Net oil and gas properties    $   287,457     $   302,016
                                    ===========     ===========


NOTE 6.  RELATED PARTY TRANSACTIONS

        Pursuant to the limited partnership agreement, the Partnership had the
following related


                                       16
   206

party transactions with the managing general partner during the years ended
December 31:



                                                 2000        1999        1998
                                               --------    --------    --------
                                                              
Payment of lease operating and supervision
  charges in accordance with standard
  industry operating agreements                $162,023    $156,380    $150,391

Reimbursement of general and administrative
  expenses                                     $ 22,916    $ 13,260    $ 11,786


        Pioneer USA, EMPL and the Partnership are parties to the Partnership
agreement. EMPL is a limited partnership in which Pioneer USA owns 77.5% and the
remaining portion is owned by former affiliates. In addition, Pioneer USA owned
634 limited partner interests at January 1, 2001.

        The costs and revenues of the Partnership are allocated as follows:



                                                         General       Limited
                                                         partners      partners
                                                         --------      --------
                                                                 
Revenues:
  Proceeds from property dispositions prior to cost
    recovery                                                10%           90%
  All other Partnership revenues                            25%           75%
Costs and expenses:
  Lease acquisition costs, drilling and completion costs    10%           90%
  Operating costs, direct costs and general and
    administrative expenses                                 25%           75%


NOTE 7.  OIL AND GAS INFORMATION (UNAUDITED)

        The following table presents information relating to the Partnership's
estimated proved oil and gas reserves at December 31, 2000, 1999 and 1998 and
changes in such quantities during the years then ended. All of the Partnership's
reserves are proved developed and located within the United States. The
Partnership's reserves are based on an evaluation prepared by Williamson
Petroleum Consultants, Inc., an independent petroleum consultant, using criteria
established by the Securities and Exchange Commission.



                                              Oil and NGLs          Gas
                                                 (bbls)            (mcf)
                                              ------------       --------
                                                           
Net proved reserves at January 1, 1998           321,477          448,047
Revisions                                       (230,755)        (305,609)
Production                                       (25,898)         (48,971)
                                                --------         --------



                                       17
   207


                                                           
Net proved reserves at December 31, 1998          64,824           93,467
Revisions                                        280,613          443,568
Production                                       (23,886)         (48,380)
                                                --------         --------

Net proved reserves at December 31, 1999         321,551          488,655
Revisions                                         60,464          362,471
Production                                       (24,158)         (45,981)
                                                --------         --------

Net proved reserves at December 31, 2000         357,857          805,145
                                                ========         ========


        As of December 31, 2000, the estimated present value of future net
revenues of proved reserves, calculated using December 31, 2000 prices of $26.55
per barrel of oil, $13.69 per barrel of NGLs and $8.68 per mcf of gas,
discounted at 10% was approximately $3,226,000 and undiscounted was $6,208,000.

        Numerous uncertainties exist in estimating quantities of proved reserves
and future net revenues therefrom. The estimates of proved reserves and related
future net revenues set forth in this Report are based on various assumptions,
which may ultimately prove to be inaccurate. Therefore, such estimates should
not be construed as estimates of the current market value of the Partnership's
proved reserves. The Partnership emphasizes that reserve estimates are
inherently imprecise and, accordingly, the estimates are expected to change as
future information becomes available.

Disclosures about Oil & Gas Producing Activities

Standardized Measure of Discounted Future Net Cash Flows

        The standardized measure of discounted future net cash flows is computed
by applying year-end prices of oil and gas (with consideration of price changes
only to the extent provided by contractual arrangements) to the estimated future
production of proved oil and gas reserves less estimated future expenditures
(based on year-end costs) to be incurred in developing and producing the proved
reserves, discounted using a rate of 10% per year to reflect the estimated
timing of the future cash flows. A Federal income tax provision has not been
calculated as the income of the Partnership is included in the individual
Federal income tax returns of the respective partners.

        Discounted future cash flow estimates like those shown below are not
intended to represent estimates of the fair value of oil and gas properties.
Estimates of fair value should also consider anticipated future oil and gas
prices, interest rates, changes in development and production costs and risks
associated with future production. Because of these and other considerations,
any estimate of fair value is necessarily subjective and imprecise.



                                                                 For the years ended December 31,
                                                               ------------------------------------
                                                                 2000          1999          1998
                                                               --------      --------      --------

                                                                          (in thousands)
                                                                                  
Oil and gas producing activities:
  Future cash inflows                                          $ 15,230      $  8,078      $    701



                                       18
   208


                                                                                  
  Future production costs                                        (9,022)       (5,386)         (624)
                                                               --------      --------      --------

                                                                  6,208         2,692            77
  10% annual discount factor                                     (2,982)       (1,056)          (11)
                                                               --------      --------      --------

  Standardized measure of discounted future net cash flows     $  3,226      $  1,636      $     66
                                                               ========      ========      ========




                                                      For the years ended December 31,
                                                     ---------------------------------
                                                       2000         1999         1998
                                                     -------      -------      -------
                                                               (in thousands)
                                                                      
Oil and Gas Producing Activities:
  Oil and gas sales, net of production costs         $  (385)     $  (128)     $   (56)
  Net changes in prices and production costs           1,448          378         (898)
  Revisions of previous quantity estimates               927        2,018         (164)
  Accretion of discount                                  164            6          118
  Changes in production rates, timing and other         (564)        (704)        (113)
                                                     -------      -------      -------

  Change in present value of future net revenues       1,590        1,570       (1,113)
                                                     -------      -------      -------

  Balance, beginning of year                           1,636           66        1,179
                                                     -------      -------      -------

  Balance, end of year                               $ 3,226      $ 1,636      $    66
                                                     =======      =======      =======


NOTE 8.  MAJOR CUSTOMERS

        The following table reflects the major customers of the Partnership's
oil and gas sales (a major customer is defined as a customer whose sales exceed
10% of total sales) during the years ended December 31:



                               2000    1999    1998
                               ----    ----    ----
                                      
Plains Marketing, L.P.          68%     66%     --
Genesis Crude Oil, L.P.         --      --      65%
GPM Gas Corporation             13%     14%     13%
Western Gas Resources, Inc.      1%      2%     10%


        At December 31, 2000, the amounts receivable from Plains Marketing, L.P.
and GPM Gas Corporation were $54,651 and $30,037, respectively, which are
included in the caption "Accounts receivable - oil and gas sales" in the
accompanying Balance Sheet.

        Pioneer USA is of the opinion that the loss of any one purchaser would
not have an adverse effect on the ability of the Partnership to sell its oil,
NGLs and gas production.


NOTE 9.  PARTNERSHIP AGREEMENT

        The following is a brief summary of the more significant provisions of
the limited partnership agreement:

        General partners - The general partners of the Partnership are Pioneer
        USA and EMPL.


                                       19
   209
        Pioneer USA, the managing general partner, has the power and authority
        to manage, control and administer all Partnership affairs. As managing
        general partner and operator of the Partnership's properties, all
        production expenses are incurred by Pioneer USA and billed to the
        Partnership. The majority of the Partnership's oil and gas revenues are
        received directly by the Partnership, however, a portion of the oil and
        gas revenue is initially received by Pioneer USA prior to being paid to
        the Partnership.

        Limited partner liability - The maximum amount of liability of any
        limited partner is the total contributions of such partner plus his
        share of any undistributed profits.

        Initial capital contributions - The limited partners entered into
        subscription agreements for aggregate capital contributions of
        $9,782,000. During 1985, the Partnership received a total of $1,372,500
        from its limited partners in response to an assessment by the managing
        general partner. Additionally, $650,000 was contributed by the managing
        general partner for limited partnership interests on unpaid assessments
        of which $500,000 was paid in 1985 and $150,000 in 1986. The general
        partners are required to contribute amounts equal to 10% of Partnership
        expenditures for lease acquisition, drilling and completion and 25% of
        direct, general and administrative and operating expenses.

ITEM 9.  CHANGES IN AND DISAGREEMENTS WITH ACCOUNTANTS ON ACCOUNTING AND
           FINANCIAL DISCLOSURE

None.


                                       20
   210

                                    PART III

ITEM 10.  DIRECTORS AND EXECUTIVE OFFICERS OF THE PARTNERSHIP

The Partnership does not have any officers or directors. Under the limited
partnership agreement, the Partnership's managing general partner, Pioneer USA,
is granted the exclusive right and full authority to manage, control and
administer the Partnership's business.

Set forth below are the names, ages and positions of the directors and executive
officers of Pioneer USA. Directors of Pioneer USA are elected to serve until the
next annual meeting of stockholders or until their successors are elected and
qualified.



                                        Age at
                                     December 31,
        Name                             2000                    Position
        ----                             ----                    --------
                                                   
  Scott D. Sheffield                      48             President

  Timothy L. Dove                         44             Executive Vice President, Chief
                                                           Financial Officer and Director

  Dennis E. Fagerstone                    51             Executive Vice President and Director

  Mark L. Withrow                         53             Executive Vice President, General
                                                           Counsel and Director

  Danny Kellum                            46             Executive Vice President - Domestic
                                                           Operations and Director

  Rich Dealy                              34             Vice President and Chief Accounting
                                                           Officer


        Scott D. Sheffield. Mr. Sheffield is a graduate of The University of
Texas with a B.S. in Petroleum Engineering. Since August 1997, he has served as
President, Chief Executive Officer and a director of Pioneer and President of
Pioneer USA. Mr. Sheffield assumed the position of Chairman of the Board of
Pioneer in August 1999. He served as a director of Pioneer USA from August 1997
until his resignation from the board in June 1999. Mr. Sheffield was the
President and a director of Parker & Parsley Petroleum Company ("Parker &
Parsley") from May 1990 until August 1997 and was the Chairman of the Board and
Chief Executive Officer of Parker & Parsley from October 1990 until August 1997.
He was the sole director of Parker & Parsley from May 1990 until October 1990.
Mr. Sheffield joined Parker & Parsley Development Company ("PPDC"), a
predecessor of Parker & Parsley, as a petroleum engineer in 1979. He served as
Vice President - Engineering of PPDC from September 1981 until April 1985 when
he was elected President and a director. In March 1989, Mr. Sheffield was
elected Chairman of the Board and Chief Executive Officer of PPDC. Before
joining PPDC's predecessor, Mr. Sheffield was employed as a production and
reservoir engineer for Amoco Production Company.

        Timothy L. Dove. Mr. Dove earned a B.S. in Mechanical Engineering from
Massachusetts


                                       21
   211

Institute of Technology in 1979 and received his M.B.A. in 1981 from the
University of Chicago. He became Executive Vice President - Business Development
of Pioneer and Pioneer USA in August 1997 and was also appointed a director of
Pioneer USA in August 1997. Mr. Dove assumed the position of Chief Financial
Officer of Pioneer and Pioneer USA effective February 1, 2000. Mr. Dove joined
Parker & Parsley in May 1994 as Vice President - International and was promoted
to Senior Vice President - Business Development in October 1996, in which
position he served until August 1997. Prior to joining Parker & Parsley, Mr.
Dove was employed with Diamond Shamrock Corp., and its successor, Maxus Energy
Corp, in various capacities in international exploration and production,
marketing, refining and marketing and planning and development.

        Dennis E. Fagerstone. Mr. Fagerstone, a graduate of the Colorado School
of Mines with a B.S. in Petroleum Engineering, became an Executive Vice
President of Pioneer and Pioneer USA in August 1997. He was also appointed a
director of Pioneer USA in August 1997. He served as Executive Vice President
and Chief Operating Officer of MESA Inc. ("Mesa") from March 1, 1997 until
August 1997. From October 1996 to February 1997, Mr. Fagerstone served as Senior
Vice President and Chief Operating Officer of Mesa and from May 1991 to October
1996, he served as Vice President - Exploration and Production of Mesa. From
June 1988 to May 1991, Mr. Fagerstone served as Vice President - Operations of
Mesa.

        Mark L. Withrow. Mr. Withrow, a graduate of Abilene Christian University
with a B.S. in Accounting and Texas Tech University with a Juris Doctorate
degree, became Executive Vice President, General Counsel and Secretary of
Pioneer and Pioneer USA in August 1997. He was also appointed a director of
Pioneer USA in August 1997. Mr. Withrow was Vice President - General Counsel of
Parker & Parsley from January 1991, when he joined Parker & Parsley, to January
1995, when he was appointed Senior Vice President - General Counsel. He was
Parker & Parsley's Secretary from August 1992 until August 1997. Prior to
joining Parker & Parsley, Mr. Withrow was the managing partner of the law firm
of Turpin, Smith, Dyer, Saxe & MacDonald, Midland, Texas.

        Danny Kellum. Mr. Kellum, who received a Bachelor of Science degree in
Petroleum Engineering from Texas Tech University in 1979, was elected Executive
Vice President - Domestic Operations of Pioneer and Pioneer USA on May 18, 2000
and Director of Pioneer USA on February 1, 2000. From January 2000 until May
2000, Mr. Kellum served as Vice President - Domestic Operations of Pioneer and
Pioneer USA. Mr. Kellum served as Vice President Permian Division of Pioneer and
Pioneer USA from April 1998 until December 1999. From 1989 until 1994 he served
as Spraberry District Manager and as Vice President of the Spraberry and Permian
Division for Parker & Parsley until August of 1997. Mr. Kellum joined Parker &
Parsley as an operations engineer in 1981 after a brief career with Mobil Oil
Corporation.

        Rich Dealy. Mr. Dealy is a graduate of Eastern New Mexico University
with a B.B.A. in Accounting and Finance and is a Certified Public Accountant. He
became Vice President and Chief Accounting Officer of Pioneer and Pioneer USA in
February 1998. Mr. Dealy served as Controller of Pioneer USA from August 1997 to
February 1998. He served as Controller of Parker & Parsley from August 1995 to
August 1997. Mr. Dealy joined Parker & Parsley as an Accounting Manager in July,
1992. He was previously employed with KPMG Peat Marwick as an Audit Senior, in
charge of Parker & Parsley's audit.


                                       22
   212

ITEM 11.  EXECUTIVE COMPENSATION

The Partnership does not have any directors or officers. Management of the
Partnership is performed by Pioneer USA, the managing general partner. Under the
Partnership agreement, Pioneer USA pays 8% of the Partnership's acquisition,
drilling and completion costs and 20% of its operating and general and
administrative expenses. In return, Pioneer USA is allocated 20% of the
Partnership's revenues.

EMPL is a co-general partner of the Partnership. Under this arrangement, EMPL
pays 2% of the Partnership's acquisition, drilling and completion costs and 5%
of its operating and general and administrative expenses. In return, EMPL is
allocated 5% of the Partnership's revenues. EMPL does not receive any fees or
reimbursements from the Partnership.

The Partnership does not directly pay any salaries of the executive officers of
Pioneer USA, but does pay a portion of Pioneer USA's general and administrative
expenses of which these salaries are a part.

See Notes 6 and 9 of Notes to Financial Statements included in "Item 8.
Financial Statements and Supplementary Data" for information regarding fees and
reimbursements paid to the managing general partner by the Partnership.

ITEM 12.  SECURITY OWNERSHIP OF CERTAIN BENEFICIAL OWNERS AND MANAGEMENT

(a)  Beneficial owners of more than five percent

The Partnership is not aware of any person who beneficially owns 5% or more of
the outstanding limited partnership interests of the Partnership. Pioneer USA
and EMPL respectively own 80% and 20% of the general partners' interests in the
Partnership. Pioneer USA owned 634 limited partner interests at January 1, 2001.

(b)  Security ownership of management

The Partnership does not have any officers or directors. The managing general
partner of the Partnership, Pioneer USA, has the exclusive right and full
authority to manage, control and administer the Partnership's business. Under
the limited partnership agreement, limited partners holding a majority of the
outstanding limited partnership interests have the right to take certain
actions, including the removal of the managing general partner or any other
general partner. The Partnership is not aware of any current arrangement or
activity which may lead to such removal. The Partnership is not aware of any
officer or director of Pioneer USA who beneficially owns limited partnership
interests in the Partnership.


                                       23
   213

ITEM 13.  CERTAIN RELATIONSHIPS AND RELATED TRANSACTIONS

Transactions with the managing general partner

Pursuant to the limited partnership agreement, the Partnership had the following
related party transactions with the managing general partner during the years
ended December 31:



                                                  2000         1999         1998
                                                --------     --------     --------

                                                                 
Payment of lease operating and supervision
   charges in accordance with standard
   industry operating agreements                $162,023     $156,380     $150,391

Reimbursement of general and administrative
   expenses                                     $ 22,916     $ 13,260     $ 11,786


Under the limited partnership agreement, the general partners, Pioneer USA and
EMPL, together pay 10% of the Partnership's acquisition, drilling and completion
costs and 25% of its operating and general and administrative expenses. In
return, they are allocated 25% of the Partnership's revenues. Twenty percent of
the general partners' share of costs and revenues is allocated to EMPL and the
remainder is allocated to Pioneer USA. Certain former affiliates of Pioneer USA
are limited partners of EMPL. Also, see Notes 6 and 9 of Notes to Financial
Statements included in "Item 8. Financial Statements and Supplementary Data"
regarding the Partnership's participation with the managing general partner in
oil and gas activities of the Partnership.


                                       24
   214

                                     PART IV


ITEM 14.  EXHIBITS, FINANCIAL STATEMENT SCHEDULES AND REPORTS ON FORM 8-K

(a)  1.  Financial statements

         The following are filed as part of this Report:

                Independent Auditors' Report

                Balance sheets as of December 31, 2000 and 1999

                Statements of operations for the years ended December 31, 2000,
                  1999 and 1998

                Statements of partners' capital for the years ended December 31,
                  2000, 1999 and 1998

                Statements of cash flows for the years ended December 31, 2000,
                  1999 and 1998

                Notes to financial statements

     2.  Financial statement schedules

         All financial statement schedules have been omitted since the required
         information is in the financial statements or notes thereto, or is not
         applicable nor required.

(b)  Reports on Form 8-K

None.

(c)  Exhibits

     The exhibits listed on the accompanying index to exhibits are filed or
     incorporated by reference as part of this Report.


                                       25
   215

                               S I G N A T U R E S

     Pursuant to the requirements of the Securities Exchange Act of 1934, the
Registrant has duly caused this Report to be signed on its behalf by the
undersigned, thereunto duly authorized.

                                   PARKER & PARSLEY 82-I, LTD.

Dated: March 23, 2001              By:   Pioneer Natural Resources USA, Inc.
                                           Managing General Partner


                                         By:  /s/ Scott D. Sheffield
                                             ---------------------------------
                                             Scott D. Sheffield, President

     Pursuant to the requirements of the Securities Exchange Act of 1934, this
Report has been signed below by the following persons on behalf of the
Registrant and in the capacities and on the date indicated.


                                                                      
/s/ Scott D. Sheffield            President of Pioneer USA                  March 23, 2001
-----------------------------
Scott D. Sheffield


/s/ Timothy L. Dove               Executive Vice President, Chief           March 23, 2001
-----------------------------     Financial Officer and Director of
Timothy L. Dove                   Pioneer USA


/s/ Dennis E. Fagerstone          Executive Vice President and              March 23, 2001
-----------------------------     Director of Pioneer USA
Dennis E. Fagerstone


/s/ Mark L. Withrow               Executive Vice President, General         March 23, 2001
-----------------------------     Counsel and Director of Pioneer USA
Mark L. Withrow


/s/ Danny Kellum                  Executive Vice President - Domestic       March 23, 2001
-----------------------------     Operations and Director of Pioneer
Danny Kellum                      USA


/s/ Rich Dealy                    Vice President and Chief Accounting       March 23, 2001
-----------------------------     Officer of Pioneer USA
Rich Dealy



                                       26
   216

                           PARKER & PARSLEY 82-I, LTD.

                                INDEX TO EXHIBITS


        The following documents are incorporated by reference in response to
Item 14(c):



  Exhibit No.                             Description                              Page
  -----------                             -----------                              ----
                                                                             
       3.1                Agreement of Limited Partnership of Parker                  -
                          & Parsley 82-I, Ltd. incorporated by reference
                          to Exhibit 4(e) of Partnership's Registration
                          Statement on Form S-1 (Registration No.
                          2-75503A), as amended on February 4, 1982,
                          the effective date thereof (hereinafter called,
                          the Partnership's Registration Statement)

       3.2                Amended and Restated Certificate of Limited                 -
                          Partnership of Parker & Parsley 82-I, Ltd.
                          incorporated by reference to Exhibit 3.2 of
                          the Partnership's Annual Report on Form 10-K
                          for the year ended December 31, 1983

       4.1                Form of Subscription Agreement and Power                    -
                          of Attorney incorporated by reference to
                          Exhibit 4(b) of the Partnership's Registration
                          Statement

       4.2                Specimen Certificate of Limited Partnership                 -
                          Interest incorporated by reference to Exhibit
                          4(d) of the Partnership's Registration Statement



                                       27
   217

                           PARKER & PARSLEY 82-I, LTD.

SELECTED FINANCIAL DATA

The following selected financial data for the Partnership should be read in
connection with Management's Discussion and Analysis of Financial Condition and
Results of Operations and the financial statements included in the attached
supplemental information.



                                        Three months
                                            ended
                                           March 31,                            Years ended December 31,
                                    ---------------------   --------------------------------------------------------------
                                      2001        2000         2000         1999         1998         1997         1996
                                    --------   ----------   ----------   ----------   ----------   ----------   ----------
                                                                                           
Operating results:
  Oil and gas sales                 $          $  172,087   $  763,858   $  441,997   $  392,883   $  608,207   $  710,173
                                    ========   ==========   ==========   ==========   ==========   ==========   ==========

  Gain on litigation
    settlement, net                 $     --   $       --   $       --   $       --   $       --   $       --   $   43,618
                                    ========   ==========   ==========   ==========   ==========   ==========   ==========

  Impairment of oil and gas
      properties                    $          $       --   $       --   $       --   $  294,610   $  165,201   $    2,277
                                    ========   ==========   ==========   ==========   ==========   ==========   ==========

  Net income (loss)                 $          $   73,617   $  337,729   $   17,320   $ (563,993)  $  (60,847)  $  312,582
                                    ========   ==========   ==========   ==========   ==========   ==========   ==========

  Allocation of net income
    (loss):
        General partners            $          $   19,763   $   88,128   $   18,135   $  (49,472)  $   31,736   $   92,811
                                    ========   ==========   ==========   ==========   ==========   ==========   ==========

        Limited partners            $          $   53,854   $  249,601   $     (815)  $ (514,521)  $  (92,583)  $  219,771
                                    ========   ==========   ==========   ==========   ==========   ==========   ==========

  Limited partners' net
    income (loss) per limited
    partnership interest            $          $    11.01   $    51.03   $     (.17)  $  (105.20)  $   (18.93)  $    44.93
                                    ========   ==========   ==========   ==========   ==========   ==========   ==========

  Limited partners' cash
    distributions per limited
    partnership interest            $          $     9.49   $    46.98   $    10.33   $    19.57   $    47.31   $    51.40(a)
                                    ========   ==========   ==========   ==========   ==========   ==========   ==========

At year end:
  Identifiable assets               $          $  438,633   $  454,904   $  425,107   $  474,528   $1,158,135   $1,526,765
                                    ========   ==========   ==========   ==========   ==========   ==========   ==========


----------

(a)  Including litigation settlement per limited partnership interest of $6.96
     in 1996.


   218
                       PIONEER NATURAL RESOURCES COMPANY
                      PIONEER NATURAL RESOURCES USA, INC.
                           1400 WILLIAMS SQUARE WEST
                           5205 NORTH O'CONNOR BLVD.
                              IRVING, TEXAS 75039

                            SUPPLEMENTAL INFORMATION

                                       OF

           PARKER & PARSLEY 82-II, LTD., A TEXAS LIMITED PARTNERSHIP

                                       TO

                  PROXY STATEMENT/PROSPECTUS DATED      , 2001

                                   ----------

                   THE DATE OF THIS SUPPLEMENT IS      , 2001

                                   ----------

     This document contains important information specific to Parker & Parsley
82-II, Ltd. and supplements the proxy statement/prospectus dated      , 2001, of
Pioneer Natural Resources Company and Pioneer Natural Resources USA, Inc., by
which Pioneer USA is soliciting proxies to be voted at a special meeting of
limited partners of the partnership. The purpose of the special meeting is for
you to vote upon the merger of the partnership with and into Pioneer USA that,
if completed, will result in your receiving common stock of Pioneer Natural
Resources Company and cash for your partnership interests.

     This document contains the following information concerning Parker &
Parsley 82-II, Ltd.:

     o    A table containing:

          --   the aggregate initial investment by the limited partners

          --   the aggregate historical limited partner distributions through
               March 31, 2001

          --   the aggregate merger value attributable to partnership interests
               of limited partners, excluding Pioneer USA

          --   the merger value per $1,000 limited partner investment as of
               March 31, 2001

          --   the merger value per $1,000 limited partner investment as a
               multiple of distributions for the 12 months ended March 31, 2001

          --   the book value per $1,000 limited partner investment as of March
               31, 2001 and as of December 31, 2000

          --   the going concern value per $1,000 limited partner investment as
               of March 31, 2001

          --   the liquidation value per $1,000 limited partner investment as of
               March 31, 2001

          --   the ordinary tax loss per $1,000 limited partner investment in
               year of initial investment

     o    Information about the legal opinion for the limited partners

     o    The partnership's quarterly report on Form 10-Q, including
          management's discussion and analysis of financial condition and
          results of operations, for the three months ended March 31, 2001

     o    The partnership's annual report on Form 10-K, including management's
          discussion and analysis of financial condition and results of
          operations, for the year ended December 31, 2000

     o    Selected historical financial data for the partnership for the three
          months ended March 31, 2001 and 2000 and the five years ended December
          31, 2000


                                      -1-
   219



                          PARKER & PARSLEY 82-II, LTD.

                         SUPPLEMENTAL INFORMATION TABLE


                                                                                          


Aggregate Initial Investment by the Limited Partners(a)                                      $  12,252

Aggregate Historical Limited Partner Distributions through March 31, 2001(a)                 $  13,831

Aggregate Merger Value Attributable to Partnership Interests of Limited Partners,            $   1,160
Excluding Pioneer USA(a)

Merger Value per $1,000 Limited Partner Investment as of March 31, 2001(b)                   $   98.29

Merger Value per $1,000 Limited Partner Investment as a Multiple of Distributions for the         4.30 times
12 Months ended March 31, 2001(b)

Book Value per $1,000 Limited Partner Investment:

          --  as of March 31, 2001(b)                                                        $

          --  as of December 31, 2000(b)                                                     $   67.39

Going Concern Value per $1,000 Limited Partner Investment as of March 31, 2001(b)            $   88.32

Liquidation Value per $1,000 Limited Partner Investment as of March 31, 2001(b)              $   95.70

Ordinary Tax Loss per $1,000 Limited Partner Investment in Year of Initial Investment        $     245
(b), (c)

-----------

(a)  Stated in thousands.

(b)  Interests in some partnerships were sold in units at prices other than
     $1,000. We have presented this information based on a $1,000 initial
     investment for ease of use and comparison among partnerships. You should
     not assume that the amount shown per $1,000 investment is the same as the
     value or amount attributable to a single unit investment.

(c)  Your ability to use your distributive share of the partnership's loss to
     offset your other income may have been subject to certain limitations at
     your level as a partner, and you may therefore wish to consult your tax
     advisor to determine the additional value, if any, actually realized by you
     in your particular circumstances.



          INFORMATION ABOUT THE LEGAL OPINION FOR THE LIMITED PARTNERS

     The partnership agreement for the partnership requires that special legal
counsel render an opinion on behalf of the limited partners to Pioneer USA that
(1) neither the grant nor the exercise of the right to approve the merger of the
partnership by its limited partners will adversely affect the federal income tax
classification of the partnership or any of its limited partners; and (2)
neither the grant nor exercise of such right will result in the loss of any
limited partner's limited liability. In addition, the counsel designated to
render the opinion must be counsel other than counsel to Pioneer USA or the
partnership. Both the designated counsel and the legal opinion must be approved
by the limited partners. Pioneer USA has retained __________ of Dallas, Texas
for the purpose of rendering this legal opinion on behalf of the limited
partners to Pioneer USA. The merger proposals include an approval of that
counsel and the form of its opinion. A copy of the opinion is attached as an
exhibit to the merger proposals.




                                      -2-
   220
                UNITED STATES SECURITIES AND EXCHANGE COMMISSION
                             WASHINGTON, D. C. 20549

                                    FORM 10-K

                  Annual Report Pursuant to Section 13 or 15(d)
                     of the Securities Exchange Act of 1934

                   FOR THE FISCAL YEAR ENDED DECEMBER 31, 2000


                          COMMISSION FILE NO. 2-75530B


                          PARKER & PARSLEY 82-II, LTD.
             (Exact name of Registrant as specified in its charter)

                    TEXAS                                    75-1867115
       -------------------------------                 ----------------------
       (State or other jurisdiction of                    (I.R.S. Employer
       incorporation or organization)                  Identification Number)


1400 WILLIAMS SQUARE WEST, 5205 N. O'CONNOR BLVD., IRVING, TEXAS         75039
----------------------------------------------------------------      ----------
               (Address of principal executive offices)               (Zip code)

       Registrant's Telephone Number, including area code: (972) 444-9001


        Securities registered pursuant to Section 12(b) of the Act: NONE
          Securities registered pursuant to Section 12(g) of the Act:
                 LIMITED PARTNERSHIP INTERESTS ($2,000 PER UNIT)
                 -----------------------------------------------

Indicate by check mark whether the Registrant (1) has filed all reports required
to be filed by Section 13 or 15(d) of the Securities Exchange Act of 1934 during
the preceding 12 months (or for such shorter period that the Registrant was
required to file such reports), and (2) has been subject to such filing
requirements for the past 90 days. YES / X / NO / /

Indicate by check mark if disclosure of delinquent filers pursuant to Item 405
of Regulation S-K is not contained herein, and will not be contained, to the
best of Registrant's knowledge, in definitive proxy or information statements
incorporated by reference in Part III of this Form 10-K or any amendment to this
Form 10-K. / X /

No market currently exists for the limited partnership interests of the
Registrant. Based on the original purchase price, the aggregate market value of
limited partnership interests owned by non-affiliates of the Registrant is
$11,800,000.

        As of March 8, 2001, the number of outstanding limited partnership
interests was 6,126.

 The following documents are incorporated by reference into the indicated parts
                    of this Annual Report on Form 10-K: None

Parts I and II of this annual report on Form 10-K (the "Report") contain forward
looking statements that involve risks and uncertainties. Accordingly, no
assurances can be given that the actual events and results will not be
materially different than the anticipated results described in the forward
looking statements. See "Item 1. Business" for a description of various factors
that could materially affect the ability of the Partnership to achieve the
anticipated results described in the forward looking statements.

   221

                                     PART I

ITEM 1. BUSINESS

Parker & Parsley 82-II, Ltd. (the "Partnership") is a limited partnership
organized in 1982 under the laws of the State of Texas. The Partnership's
managing general partner is Pioneer Natural Resources USA, Inc. ("Pioneer USA")
and its co-general partner is P&P Employees 82-II, Ltd. ("EMPL"), a Texas
limited partnership whose general partner is Pioneer USA. Pioneer USA is a
wholly-owned subsidiary of Pioneer Natural Resources Company ("Pioneer"). As of
March 8, 2001, the Partnership had 6,126 limited partnership interests
outstanding.

The Partnership does not have any employees of its own. Pioneer USA employs 701
persons, many of whom dedicated a part of their time to the conduct of the
Partnership's business during the period for which this Report is filed. Pioneer
USA supplies all management functions.

The Partnership engages in oil and gas development and production and is not
involved in any industry segment other than oil and gas. The Partnership's
production is geographically concentrated in West Texas.

The principal markets during 2000 for the oil produced by the Partnership were
refineries and oil transmission companies that have facilities near the
Partnership's oil producing properties. During 2000, Pioneer USA marketed the
Partnership's gas to a variety of purchasers, none of which accounted for 10% or
more of the Partnership's oil and gas revenues. Of the Partnership's total oil
and gas revenues for 2000, approximately 70% was attributable to sales made to
Plains Marketing, L.P. Pioneer USA is of the opinion that the loss of any one
purchaser would not have an adverse effect on its ability to sell its oil,
natural gas liquids ("NGLs") and gas production.

The Partnership's revenues, profitability, cash flow and future rate of growth
are highly dependent on the prevailing prices of oil and gas, which are affected
by numerous factors beyond the Partnership's control. Oil and gas prices
historically have been very volatile. A substantial or extended decline in the
prices of oil or gas could have a material adverse effect on the Partnership's
revenues, profitability and cash flow and could, under certain circumstances,
result in a reduction in the carrying value of the Partnership's oil and gas
properties.

Oil and gas production operations are subject to various types of regulations by
local, state and federal agencies. The Partnership's operations are also subject
to state conservation laws and regulations, including the establishment of
maximum rates of production from wells and the regulation of spacing, plugging
and abandonment of wells. Each state generally imposes a production or severance
tax with respect to production and sale of oil and gas within their respective
jurisdictions. Noncompliance with the laws and regulations may subject the
Partnership to penalties, damages or other liabilities and compliance may
increase the cost of the Partnership's operations. The oil and gas business is
also subject to environmental hazards such as oil spills, gas leaks and


                                       2
   222

ruptures and discharges of toxic substances or gases that could expose the
Partnership to substantial liability due to pollution and other environmental
damages. Although the Partnership believes that its business operations do not
impair environmental quality and that its costs of complying with any applicable
environmental regulations are not currently significant, the Partnership cannot
predict what, if any, effect these environmental regulations may have on its
current or future operations.

Numerous uncertainties exist in estimating quantities of proved reserves and
future net revenues therefrom. The estimates of proved reserves and related
future net revenues set forth in this Report are based on various assumptions,
which may ultimately prove to be inaccurate. Therefore, such estimates should
not be construed as estimates of the current market value of the Partnership's
proved reserves.

No material part of the Partnership's business is seasonal and the Partnership
conducts no foreign operations.

ITEM 2. PROPERTIES

The Partnership's properties consist of leasehold interests in properties on
which oil and gas wells are located. Such property interests are often subject
to landowner royalties, overriding royalties and other oil and gas leasehold
interests.

Fractional working interests in developmental and exploratory oil and gas
prospects located in Texas and New Mexico were acquired by the Partnership,
resulting in the Partnership's participation in the drilling of 52 oil and gas
wells. At December 31, 2000, the Partnership had 16 producing oil and gas wells.
Two wells were plugged and abandoned, five wells were dry holes and 29 wells
have been sold.

For information relating to the Partnership's estimated proved oil and gas
reserves at December 31, 2000, 1999 and 1998, and changes in such quantities for
the years then ended, see Note 7 of Notes to Financial Statements included in
"Item 8. Financial Statements and Supplementary Data" below. Such reserves have
been evaluated by Williamson Petroleum Consultants, Inc., an independent
petroleum consultant.

ITEM 3. LEGAL PROCEEDINGS

The Partnership from time to time is a party to various legal proceedings
incidental to its business involving claims in oil and gas leases or interests,
other claims for damages in amounts not in excess of 10% of its current assets
and other matters, none of which Pioneer USA believes to be material to the
Partnership.

ITEM 4. SUBMISSION OF MATTERS TO A VOTE OF SECURITY HOLDERS

There were no matters submitted to a vote of the partners during the fourth
quarter of 2000.


                                       3
   223
                                     PART II

ITEM 5. MARKET FOR LIMITED PARTNERSHIP INTERESTS AND LIMITED PARTNERSHIP
          DISTRIBUTIONS

At March 8, 2001, the Partnership had 6,126 outstanding limited partnership
interests held of record by 772 subscribers. There is no established public
trading market for the limited partnership interests. Under the limited
partnership agreement, Pioneer USA has made certain commitments to purchase
partnership interests at a computed value.

Revenues which, in the sole judgement of the general partners, are not required
to meet the Partnership's obligations are distributed to the partners at least
quarterly in accordance with the limited partnership agreement. During the years
ended December 31, 2000 and 1999, distributions of $270,025 and $93,647,
respectively, were made to the limited partners.

ITEM 6. SELECTED FINANCIAL DATA

The following table sets forth selected financial data for the years ended
December 31:



                                   2000           1999           1998           1997           1996
                                 ----------     ----------     ----------     ----------     ----------
                                                                              

Operating results:
-----------------
  Oil and gas sales              $  730,936     $  477,533     $  379,887     $  598,339     $  732,599
                                 ==========     ==========     ==========     ==========     ==========

  Gain on litigation
   settlement, net               $       --     $       --     $       --     $       --     $   45,027
                                 ==========     ==========     ==========     ==========     ==========

  Impairment of oil and gas
   properties                    $       --     $       --     $   65,229     $  310,732     $       --
                                 ==========     ==========     ==========     ==========     ==========

  Net income (loss)              $  350,536     $  120,353     $ (131,488)    $  (93,386)    $  322,918
                                 ==========     ==========     ==========     ==========     ==========

  Allocation of net income
   (loss):
     General partner             $   94,215     $   38,680     $    2,863     $   30,221     $   98,377
                                 ==========     ==========     ==========     ==========     ==========

     Limited partners            $  256,321     $   81,673     $ (134,351)    $ (123,607)    $  224,541
                                 ==========     ==========     ==========     ==========     ==========

  Limited partners' net
   income (loss) per limited
   partnership interest          $    41.84     $    13.33     $   (21.93)    $   (20.18)    $    36.65
                                 ==========     ==========     ==========     ==========     ==========

  Limited partners' cash
   distributions per limited
   partnership interest          $    44.08     $    15.29     $   (46.67)    $    43.00     $    49.38 (a)
                                 ==========     ==========     ==========     ==========     ==========

At year end:
-----------
  Identifiable assets            $  960,300     $  971,351     $  971,390     $1,456,326     $1,893,741
                                 ==========     ==========     ==========     ==========     ==========


---------------

(a) Including litigation settlement per limited partnership interest of $6.02 in
    1996.


                                       4
   224

ITEM 7. MANAGEMENT'S DISCUSSION AND ANALYSIS OF FINANCIAL CONDITION AND RESULTS
          OF OPERATIONS

Results of operations

2000 compared to 1999

The Partnership's oil and gas revenues increased 53% to $730,936 for 2000 as
compared to $477,533 in 1999. The increase in revenues resulted from higher
average prices received, offset by a decline in production. In 2000, 17,293
barrels of oil, 7,629 barrels of natural gas liquids ("NGLs") and 35,900 mcf of
gas were sold, or 30,905 barrel of oil equivalents ("BOEs"). In 1999, 17,967
barrels of oil, 9,587 barrels of NGLs and 42,858 mcf of gas were sold, or 34,697
BOEs. Due to the decline characteristics of the Partnership's oil and gas
properties, management expects a certain amount of decline in production in the
future until the Partnership's economically recoverable reserves are fully
depleted.

The average price received per barrel of oil increased $12.39, or 73%, from
$17.08 in 1999 to $29.47 in 2000. The average price received per barrel of NGLs
increased $5.21, or 53%, from $9.80 in 1999 to $15.01 in 2000. The average price
received per mcf of gas increased 66% from $1.79 in 1999 to $2.98 in 2000. The
market price for oil and gas has been extremely volatile in the past decade and
management expects a certain amount of volatility to continue in the foreseeable
future. The Partnership may therefore sell its future oil and gas production at
average prices lower or higher than that received in 2000.

Total costs and expenses increased in 2000 to $387,226 as compared to $361,025
in 1999, an increase of $26,201, or 7%. This increase was due to increases in
production costs and general and administrative expenses ("G&A"), offset by a
decline in depletion.

Production costs were $316,735 in 2000 and $280,719 in 1999, resulting in an
increase of $36,016, or 13%. The increase was primarily due to higher production
taxes associated with higher oil and gas prices and additional well maintenance
costs incurred to stimulate well production.

G&A's components are independent accounting and engineering fees and managing
general partner personnel and operating costs. During this period, G&A increased
28%, from $19,626 in 1999 to $25,120 in 2000 primarily due to a higher
percentage of the managing general partner's G&A being allocated (limited to 3%
of oil and gas revenues) as a result of increased oil and gas revenues. The
Partnership paid the managing general partner $21,928 in 2000 and $14,326 in
1999 for G&A incurred on behalf of the Partnership. The remaining G&A was paid
directly by the Partnership. The managing general partner determines the
allocated expenses based upon the level of activity of the Partnership relative
to the non-partnership activities of the managing general partner. The method of
allocation has been consistent over the past several years with certain
modifications incorporated to reflect changes in Pioneer USA's overall business
activities.

Depletion was $45,371 in 2000 as compared to $60,680 in 1999, a decrease of
$15,309, or 25%. This decrease was primarily due to a 21,082 barrels of oil
increase in proved reserves during 2000 as a result of higher commodity prices.

1999 compared to 1998

The Partnership's 1999 oil and gas revenues increased 26% to $477,533 from
$379,887 in 1998. The increase in revenues resulted from higher average prices
received, offset by a decline in production. In 1999, 17,967 barrels of oil,
9,587 barrels of NGLs and 42,858 mcf of gas were sold, or 34,697 BOEs. In 1998,
19,042 barrels of oil, 8,812 barrels of NGLs and 41,862 mcf of gas were sold, or



                                       5
   225

34,831 BOEs.

The average price received per barrel of oil increased $3.94, or 30%, from
$13.14 in 1998 to $17.08 in 1999. The average price received per barrel of NGLs
increased $2.87, or 41%, from $6.93 in 1998 to $9.80 in 1999. The average price
received per mcf of gas increased 9% from $1.64 in 1998 to $1.79 in 1999.

A gain on disposition of assets of $1,281 was recognized during 1998 from post
closing adjustments received from the sale of six oil and gas wells and an
overriding royalty interest in one well during 1997.

Total costs and expenses decreased in 1999 to $361,025 as compared to $523,894
in 1998, a decrease of $162,869, or 31%. The decrease was primarily due to
declines in depletion and the impairment of oil and gas properties, offset by
increases in production costs and G&A expenses.

Production costs were $280,719 in 1999 and $274,382 in 1998, resulting in an
increase of $6,337, or 2%. The increase was primarily due to additional well
maintenance costs incurred to stimulate well production and an increase in
production taxes due to increased oil and gas revenues, offset by a decline in
ad valorem taxes.

During this period, G&A increased 45% from $13,493 in 1998 to $19,626 in 1999
primarily due to a higher percentage of the managing general partner's G&A being
allocated (limited to 3% of oil and gas revenues) as a result of increased oil
and gas revenues. The Partnership paid the managing general partner $14,326 in
1999 and $11,397 in 1998 for G&A incurred on behalf of the Partnership.

In accordance with Statement of Financial Accounting Standards No. 121,
"Accounting for the Impairment of Long-Lived Assets and for Long-Lived Assets to
be Disposed Of" ("SFAS 121"), the managing general partner reviews the
Partnership's oil and gas properties for impairment whenever events or
circumstances indicate a decline in the recoverability of the carrying value of
the Partnership's assets may have occurred. As a result of the review and
evaluation of its long-lived assets for impairment, the Partnership recognized a
non-cash charge of $65,229 related to its oil and gas properties during 1998.

Depletion was $60,680 in 1999 compared to $170,790 in 1998, a decrease of
$110,110, or 64%. This decrease was the result of an increase in proved reserves
of 182,544 barrels of oil during 1999 as a result of higher commodity prices and
a reduction in the Partnership's net depletable basis in accordance with SFAS
121 during the fourth quarter of 1998.


Petroleum industry

The petroleum industry has been characterized by volatile oil, NGL and natural
gas commodity prices and relatively stable supplier costs during the three years
ended December 31, 2000. During 1998, weather patterns, regional economic
recessions and political matters combined to cause worldwide oil supplies to
exceed demand resulting in a substantial decline in oil prices. Also during
1998, but to a lesser extent, market prices for natural gas declined. During
1999 and 2000, the Organization


                                       6
   226

of Petroleum Exporting Countries ("OPEC") and certain other crude oil exporting
nations announced reductions in their planned export volumes. Those
announcements, together with the enactment of the announced reductions in export
volumes, had a positive impact on world oil prices, as have overall natural gas
supply and demand fundamentals on North American natural gas prices. Although
the favorable commodity price environment and stable field service cost
environment is expected to continue during 2001, there is no assurance that
commodity prices will not return to a less favorable level or that field service
costs will not escalate in the future, both of which could negatively impact the
Partnership's future results of operations and cash distributions.

Liquidity and capital resources

Net Cash Provided by Operating Activities

Net cash provided by operating activities increased $202,645 during the year
ended December 31, 2000 from 1999. This increase was due to an increase in oil
and gas sales receipts of $256,384, offset by increases in production costs paid
of $36,016, G&A expenses paid of $5,494 and working capital of $12,229. The
increase in oil and gas receipts resulted from the increase in commodity prices
during 2000 which contributed an additional $326,338 to oil and gas receipts,
offset by $69,954 resulting from the decline in production during 2000. The
increase in production costs was primarily due to increased production taxes
associated with higher oil and gas prices and well maintenance costs incurred to
stimulate well production. The increase in G&A was primarily due to higher
percentage of the managing general partner's G&A being allocated (limited to 3%
of oil and gas revenues) as a result of increased oil and gas revenues.

Net Cash Provided by (Used in) Investing Activities

The Partnership's principal investing activities during 2000 and 1999 included
expenditures related to equipment upgrades on several oil and gas properties.

Proceeds from asset dispositions of $422 in 1999 were from equipment credits
received on active properties. During 1998, proceeds from disposition of assets
of $153,683 were primarily from the sale of six oil and gas wells during 1997.

Net Cash Used in Financing Activities

In 2000, cash distributions to the partners were $361,123, of which $91,098 was
distributed to the general partners and $270,025 to the limited partners. In
1999, cash distributions to the partners were $124,365, of which $30,718 was
distributed to the general partners and $93,647 to the limited partners.


                                       7
   227

ITEM 8. FINANCIAL STATEMENTS AND SUPPLEMENTARY DATA


                          INDEX TO FINANCIAL STATEMENTS



                                                                         Page
                                                                         ----
                                                                      
Financial Statements of Parker & Parsley 82-II, Ltd:
 Independent Auditors' Report............................................  9
 Balance Sheets as of December 31, 2000 and 1999......................... 10
 Statements of Operations for the Years Ended December 31,
   2000, 1999 and 1998................................................... 11
 Statements of Partners' Capital for the Years Ended
   December 31, 2000, 1999 and 1998...................................... 12
 Statements of Cash Flows for the Years Ended December 31,
   2000, 1999 and 1998................................................... 13
 Notes to Financial Statements........................................... 14



                                       8
   228

                          INDEPENDENT AUDITORS' REPORT


The Partners
Parker & Parsley 82-II, Ltd.
  (A Texas Limited Partnership):

We have audited the balance sheets of Parker & Parsley 82-II, Ltd. as of
December 31, 2000 and 1999, and the related statements of operations, partners'
capital and cash flows for each of the three years in the period ended December
31, 2000. These financial statements are the responsibility of the Partnership's
management. Our responsibility is to express an opinion on these financial
statements based on our audits.

We conducted our audits in accordance with auditing standards generally accepted
in the United States. Those standards require that we plan and perform the audit
to obtain reasonable assurance about whether the financial statements are free
of material misstatement. An audit includes examining, on a test basis, evidence
supporting the amounts and disclosures in the financial statements. An audit
also includes assessing the accounting principles used and significant estimates
made by management, as well as evaluating the overall financial statement
presentation. We believe that our audits provide a reasonable basis for our
opinion.

In our opinion, the financial statements referred to above present fairly, in
all material respects, the financial position of Parker & Parsley 82-II, Ltd. as
of December 31, 2000 and 1999, and the results of its operations and its cash
flows for each of the three years in the period ended December 31, 2000, in
conformity with accounting principles generally accepted in the United States.



                                                   Ernst & Young LLP


Dallas, Texas
March 9, 2001


                                       9
   229

                          PARKER & PARSLEY 82-II, LTD.
                          (A Texas Limited Partnership)

                                 BALANCE SHEETS
                                   December 31




                                                      2000             1999
                                                   -----------      -----------
                                                              
               ASSETS
               ------

Current assets:
  Cash                                             $    77,911      $    91,672
  Accounts receivable - oil and gas sales              107,778           68,374
                                                   -----------      -----------

         Total current assets                          185,689          160,046
                                                   -----------      -----------

Oil and gas properties - at cost, based on the
  successful efforts accounting method               8,305,901        8,297,224
Accumulated depletion                               (7,531,290)      (7,485,919)
                                                   -----------      -----------

         Net oil and gas properties                    774,611          811,305
                                                   -----------      -----------

                                                   $   960,300      $   971,351
                                                   ===========      ===========

LIABILITIES AND PARTNERS' CAPITAL
---------------------------------

Current liabilities:
  Accounts payable - affiliate                     $    12,662      $    13,126

Partners' capital:
  General partners                                     121,968          118,851
  Limited partners (6,126 interests)                   825,670          839,374
                                                   -----------      -----------

                                                       947,638          958,225
                                                   -----------      -----------

                                                   $   960,300      $   971,351
                                                   ===========      ===========



   The accompanying notes are an integral part of these financial statements.


                                       10
   230

                          PARKER & PARSLEY 82-II, LTD.
                          (A Texas Limited Partnership)

                            STATEMENTS OF OPERATIONS
                         For the years ended December 31




                                             2000          1999          1998
                                           ---------     ---------     ---------

                                                              
Revenues:
  Oil and gas                              $ 730,936     $ 477,533     $ 379,887
  Interest                                     6,826         3,845        11,238
  Gain on disposition of assets                   --            --         1,281
                                           ---------     ---------     ---------

                                             737,762       481,378       392,406
                                           ---------     ---------     ---------

Costs and expenses:
  Oil and gas production                     316,735       280,719       274,382
  General and administrative                  25,120        19,626        13,493
  Impairment of oil and gas properties            --            --        65,229
  Depletion                                   45,371        60,680       170,790
                                           ---------     ---------     ---------

                                             387,226       361,025       523,894
                                           ---------     ---------     ---------

Net income (loss)                          $ 350,536     $ 120,353     $(131,488)
                                           =========     =========     =========

Allocation of net income (loss):
  General partners                         $  94,215     $  38,680     $   2,863
                                           =========     =========     =========

  Limited partners                         $ 256,321     $  81,673     $(134,351)
                                           =========     =========     =========

Net income (loss) per limited
  partnership interest                     $   41.84     $   13.33     $  (21.93)
                                           =========     =========     =========



   The accompanying notes are an integral part of these financial statements.


                                       11
   231

                          PARKER & PARSLEY 82-II, LTD.
                          (A Texas Limited Partnership)

                         STATEMENTS OF PARTNERS' CAPITAL




                                            General          Limited
                                            partners         partners           Total
                                           -----------      -----------      -----------

                                                                    
Partners' capital at January 1, 1998       $   167,998      $ 1,271,605      $ 1,439,603

  Distributions                                (59,972)        (285,906)        (345,878)

  Net income (loss)                              2,863         (134,351)        (131,488)
                                           -----------      -----------      -----------

Partners' capital at December 31, 1998         110,889          851,348          962,237

  Distributions                                (30,718)         (93,647)        (124,365)

  Net income                                    38,680           81,673          120,353
                                           -----------      -----------      -----------

Partners' capital at December 31, 1999         118,851          839,374          958,225

  Distributions                                (91,098)        (270,025)        (361,123)

  Net income                                    94,215          256,321          350,536
                                           -----------      -----------      -----------

Partners' capital at December 31, 2000     $   121,968      $   825,670      $   947,638
                                           ===========      ===========      ===========



   The accompanying notes are an integral part of these financial statements.


                                       12
   232

                          PARKER & PARSLEY 82-II, LTD.
                          (A Texas Limited Partnership)

                            STATEMENTS OF CASH FLOWS
                         For the years ended December 31




                                                       2000          1999          1998
                                                     ---------     ---------     ---------
                                                                        
Cash flows from operating activities:
  Net income (loss)                                  $ 350,536     $ 120,353     $(131,488)
  Adjustments to reconcile net income (loss)
    to net cash provided by operating activities:
      Impairment of oil and gas properties                  --            --        65,229
      Depletion                                         45,371        60,680       170,790
      Gain on disposition of assets                         --            --        (1,281)
  Changes in assets and liabilities:
      Accounts receivable                              (39,404)      (31,612)       23,310
      Accounts payable                                    (464)        3,973        (7,570)
                                                     ---------     ---------     ---------

        Net cash provided by operating activities      356,039       153,394       118,990
                                                     ---------     ---------     ---------

Cash flows from investing activities:
  Additions to oil and gas properties                   (8,677)       (2,053)      (13,600)
  Proceeds from asset dispositions                          --           422       153,683
                                                     ---------     ---------     ---------

        Net cash provided by (used in)
          investing activities                          (8,677)       (1,631)      140,083
                                                     ---------     ---------     ---------

Cash flows used in financing activities:
  Cash distributions to partners                      (361,123)     (124,365)     (345,878)
                                                     ---------     ---------     ---------

Net increase (decrease) in cash                        (13,761)       27,398       (86,805)
Cash at beginning of year                               91,672        64,274       151,079
                                                     ---------     ---------     ---------

Cash at end of year                                  $  77,911     $  91,672     $  64,274
                                                     =========     =========     =========



   The accompanying notes are an integral part of these financial statements.


                                       13
   233

                          PARKER & PARSLEY 82-II, LTD.
                          (A Texas Limited Partnership)

                          NOTES TO FINANCIAL STATEMENTS
                        December 31, 2000, 1999 and 1998

NOTE 1. ORGANIZATION AND NATURE OF OPERATIONS

        Parker & Parsley 82-II, Ltd. (the "Partnership") is a limited
partnership organized in 1982 under the laws of the State of Texas. The
Partnership's general partners are Pioneer Natural Resources USA, Inc. ("Pioneer
USA") and P&P Employees 82-II, Ltd. ("EMPL"). The Partnership's managing general
partner is Pioneer USA.

        The Partnership engages in oil and gas development and production in
Texas and is not involved in any industry segment other than oil and gas.

NOTE 2. SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES

        A summary of the significant accounting policies consistently applied in
the preparation of the accompanying financial statements follows:

        Oil and gas properties - The Partnership utilizes the successful efforts
method of accounting for its oil and gas properties and equipment. Under this
method, all costs associated with productive wells and nonproductive development
wells are capitalized while nonproductive exploration costs are expensed.
Capitalized costs relating to proved properties are depleted using the
unit-of-production method on a property-by-property basis based on proved oil
(dominant mineral) reserves as evaluated by independent petroleum consultants.
The carrying amounts of properties sold or otherwise disposed of and the related
allowances for depletion are eliminated from the accounts and any gain or loss
is included in results of operations.

        Impairment of long-lived assets - In accordance with Statement of
Financial Accounting Standards No. 121, "Accounting for the Impairment of
Long-Lived Assets and for Long-Lived Assets to be Disposed Of" ("SFAS 121"), the
Partnership reviews its long-lived assets to be held and used on an individual
property basis, including oil and gas properties accounted for under the
successful efforts method of accounting, whenever events or circumstances
indicate that the carrying value of those assets may not be recoverable. An
impairment loss is indicated if the sum of the expected future cash flows is
less than the carrying amount of the assets. In this circumstance, the
Partnership recognizes an impairment loss for the amount by which the carrying
amount of the asset exceeds the estimated fair value of the asset.

        Use of estimates in the preparation of financial statements -
Preparation of the accompanying financial statements in conformity with
generally accepted accounting principles requires management to make estimates
and assumptions that affect the reported amounts of assets and liabilities and
disclosure of contingent assets and liabilities at the date of the financial
statements and the reported amounts of revenues and expenses during the
reporting periods. Actual results could differ from those estimates.


                                       14
   234


        Net income (loss) per limited partnership interest - The net income
(loss) per limited partnership interest is calculated by using the number of
outstanding limited partnership interests.

        Income taxes - A Federal income tax provision has not been included in
the financial statements as the income of the Partnership is included in the
individual Federal income tax returns of the respective partners.

        Statements of cash flows - For purposes of reporting cash flows, cash
includes depository accounts held by banks.

        General and administrative expenses - General and administrative
expenses are allocated in part to the Partnership by the managing general
partner. Allocated expenses are determined by the managing general partner based
upon the level of activity of the Partnership relative to the non-partnership
activities of the managing general partner. The method of allocation has been
consistent over the past several years with certain modifications incorporated
to reflect changes in Pioneer USA's overall business activities.

        Reclassifications - Certain reclassifications may have been made to the
1999 and 1998 financial statements to conform to the 2000 financial statement
presentations.

        Environmental - The Partnership is subject to extensive federal, state
and local environmental laws and regulations. These laws, which are constantly
changing, regulate the discharge of materials into the environment and may
require the Partnership to remove or mitigate the environmental effects of the
disposal or release of petroleum or chemical substances at various sites.
Environmental expenditures are expensed or capitalized depending on their future
economic benefit. Expenditures that relate to an existing condition caused by
past operations and that have no future economic benefits are expensed.
Liabilities for expenditures of a noncapital nature are recorded when
environmental assessment and/or remediation is probable, and the costs can be
reasonably estimated. Such liabilities are generally undiscounted unless the
timing of cash payments for the liability or component are fixed or reliably
determinable. No such liabilities have been accrued as of December 31, 2000.

        Revenue recognition - The Partnership uses the entitlements method of
accounting for oil, natural gas liquids ("NGLs") and natural gas revenues.

NOTE 3. IMPAIRMENT OF LONG-LIVED ASSETS

        In accordance with SFAS 121, the Partnership reviews its proved oil and
gas properties for impairment whenever events and circumstances indicate a
decline in the recoverability of the carrying value of the Partnership's oil and
gas properties. The Partnership has estimated the expected future cash flows of
its oil and gas properties as of December 31, 2000, 1999 and 1998, based on
proved reserves, and compared such estimated future cash flows to the respective
carrying amount of the oil and gas properties to determine if the carrying
amounts were likely to be recoverable. For those proved oil and gas properties
for which the carrying amount exceeded the estimated future cash flows, an
impairment was determined to exist; therefore, the Partnership adjusted the
carrying amount of those oil and gas properties to their fair value as
determined by discounting their expected future cash flows at a discount rate
commensurate with the risks involved in the industry. As a result, the


                                       15
   235

Partnership recognized a non-cash impairment provision of $65,229 related to its
proved oil and gas properties during 1998.

NOTE 4. INCOME TAXES

        The financial statement basis of the Partnership's net assets and
liabilities was $425,788 less than the tax basis at December 31, 2000.

        The following is a reconciliation of net income (loss) per statements of
operations with the net income per Federal income tax returns for the years
ended December 31:



                                                         2000          1999         1998
                                                      ---------     ---------    ---------

                                                                        
Net income (loss) per statements of operations        $ 350,536     $ 120,353    $(131,488)
Depletion and depreciation provisions for tax
  reporting purposes less than amounts for
  financial reporting purposes                           39,685        55,288      163,319
Impairment of oil and gas properties for financial
  reporting purposes                                         --            --       65,229
Other, net                                                 (932)          209          217
                                                      ---------     ---------    ---------

      Net income per Federal income tax
        returns                                       $ 389,289     $ 175,850    $  97,277
                                                      =========     =========    =========


NOTE 5. OIL AND GAS PRODUCING ACTIVITIES

        The following is a summary of the costs incurred, whether capitalized or
expensed, related to the Partnership's oil and gas producing activities for the
years ended December 31:



                        2000         1999       1998
                     ---------    ---------    -------

                                      
Development costs    $   8,677    $   2,053    $13,600
                     =========    =========    =======


        Capitalized oil and gas properties consist of the following:



                                       2000            1999
                                   -----------     -----------
                                             
Proved properties:
  Property acquisition costs       $   415,980     $   415,980
  Completed wells and equipment      7,889,921       7,881,244
                                   -----------     -----------

                                     8,305,901       8,297,224
Accumulated depletion               (7,531,290)     (7,485,919)
                                   -----------     -----------

  Net oil and gas properties       $   774,611     $   811,305
                                   ===========     ===========



                                       16
   236

NOTE 6. RELATED PARTY TRANSACTIONS

        Pursuant to the limited partnership agreement, the Partnership had the
following related party transactions with the managing general partner during
the years ended December 31:



                                                 2000        1999        1998
                                               --------    --------    --------
                                                              
Payment of lease operating and supervision
  charges in accordance with standard
  industry operating agreements                $143,855    $139,170    $133,844

Reimbursement of general and administrative
  expenses                                     $ 21,928    $ 14,326    $ 11,397


        Pioneer USA, EMPL and the Partnership are parties to the Partnership
agreement. EMPL is a limited partnership in which Pioneer USA owns 83% and the
remaining portion is owned by former affiliates. In addition, Pioneer USA owned
226 limited partner interests at January 1, 2001.

        The costs and revenues of the Partnership are allocated as follows:



                                                          General      Limited
                                                          partners     partners
                                                          --------     --------
                                                                 
Revenues:
  Proceeds from property dispositions prior to cost
    recovery                                                 10%          90%
  All other Partnership revenues                             25%          75%
Costs and expenses:
  Lease acquisition costs, drilling and completion costs     10%          90%
  Operating costs, direct costs and general and
    administrative expenses                                  25%          75%


NOTE 7. OIL AND GAS INFORMATION (UNAUDITED)

        The following table presents information relating to the Partnership's
estimated proved oil and gas reserves at December 31, 2000, 1999 and 1998 and
changes in such quantities during the years then ended. All of the Partnership's
reserves are proved developed and located within the United States. The
Partnership's reserves are based on an evaluation prepared by Williamson
Petroleum Consultants, Inc., an independent petroleum consultant, using criteria
established by the Securities and Exchange Commission.


                                       17
   237


                                          Oil and NGLs      Gas
                                             (bbls)        (mcf)
                                          ------------   --------

                                                  
Net proved reserves at January 1, 1998       376,355      512,848
Revisions                                   (163,438)    (164,998)
Production                                   (27,854)     (41,862)
                                            --------     --------

Net proved reserves at December 31, 1998     185,063      305,988
Revisions                                    288,622      425,997
Production                                   (27,554)     (42,858)
                                            --------     --------

Net proved reserves at December 31, 1999     446,131      689,127
Revisions                                    (13,008)     (29,574)
Production                                   (24,922)     (35,900)
                                            --------     --------

Net proved reserves at December 31, 2000     408,201      623,653
                                            ========     ========


        As of December 31, 2000, the estimated present value of future net
revenues of proved reserves, calculated using December 31, 2000 prices of $26.58
per barrel of oil, $13.60 per barrel of NGLs and $8.05 per mcf of gas,
discounted at 10% was approximately $3,222,000 and undiscounted was $6,505,000.

        Numerous uncertainties exist in estimating quantities of proved reserves
and future net revenues therefrom. The estimates of proved reserves and related
future net revenues set forth in this Report are based on various assumptions,
which may ultimately prove to be inaccurate. Therefore, such estimates should
not be construed as estimates of the current market value of the Partnership's
proved reserves. The Partnership emphasizes that reserve estimates are
inherently imprecise and, accordingly, the estimates are expected to change as
future information becomes available.

Disclosures about Oil & Gas Producing Activities

Standardized Measure of Discounted Future Net Cash Flows

        The standardized measure of discounted future net cash flows is computed
by applying year-end prices of oil and gas (with consideration of price changes
only to the extent provided by contractual arrangements) to the estimated future
production of proved oil and gas reserves less estimated future expenditures
(based on year-end costs) to be incurred in developing and producing the proved
reserves, discounted using a rate of 10% per year to reflect the estimated
timing of the future cash flows. A Federal income tax provision has not been
calculated as the income of the Partnership is included in the individual
Federal income tax returns of the respective partners.

        Discounted future cash flow estimates like those shown below are not
intended to represent estimates of the fair value of oil and gas properties.
Estimates of fair value should also consider anticipated future oil and gas
prices, interest rates, changes in development and production costs and risks
associated with future production. Because of these and other considerations,
any estimate of fair value is necessarily subjective and imprecise.


                                       18
   238


                                                               For the years ended December 31,
                                                              ----------------------------------
                                                                2000         1999         1998
                                                              --------     --------     --------

                                                                         (in thousands)
                                                                               
Oil and gas producing activities:
  Future cash inflows                                         $ 14,233     $ 11,083     $  2,024
  Future production costs                                       (7,728)      (6,439)      (1,464)
                                                              --------     --------     --------

                                                                 6,505        4,644          560
  10% annual discount factor                                    (3,283)      (2,235)        (228)
                                                              --------     --------     --------

  Standardized measure of discounted future net cash flows    $  3,222     $  2,409     $    332
                                                              ========     ========     ========




                                                        For the years ended December 31,
                                                       ---------------------------------
                                                         2000         1999         1998
                                                       -------      -------      -------
                                                                 (in thousands)
                                                                        
  Oil and Gas Producing Activities:
    Oil and gas sales, net of production costs         $  (414)     $  (197)     $  (106)
    Net changes in prices and production costs           1,300          807         (871)
    Revisions of previous quantity estimates              (118)       1,768         (241)
    Accretion of discount                                  240           33          147
    Changes in production rates, timing and other         (195)        (334)         (72)
                                                       -------      -------      -------

    Change in present value of future net revenues         813        2,077       (1,143)
                                                       -------      -------      -------

    Balance, beginning of year                           2,409          332        1,475
                                                       -------      -------      -------

    Balance, end of year                               $ 3,222      $ 2,409      $   332
                                                       =======      =======      =======


NOTE 8. MAJOR CUSTOMERS

        The following table reflects the major customers of the Partnership's
oil and gas sales (a major customer is defined as a customer whose sales exceed
10% of total sales) during the years ended December 31:



                                            2000        1999         1998
                                          --------    --------     --------
                                                          
        Plains Marketing, L.P.               70%          65%          -
        Genesis Crude Oil, L.P.               -            -          66%
        Western Gas Resources, Inc.           2%           5%         21%


        At December 31, 2000, the amount receivable from Plains Marketing, L.P.
was $56,201 which is included in the caption "Accounts receivable - oil and gas
sales" in the accompanying Balance Sheet.

        Pioneer USA is of the opinion that the loss of any one purchaser would
not have an adverse effect on the ability of the Partnership to sell its oil,
NGLs and gas production.

NOTE 9. PARTNERSHIP AGREEMENT

        The following is a brief summary of the more significant provisions of
the limited partnership agreement:

        General partners - The general partners of the Partnership are Pioneer
        USA and EMPL. Pioneer USA, the managing general partner, has the power
        and authority to manage, control


                                       19
   239

        and administer all Partnership affairs. As managing general partner and
        operator of the Partnership's properties, all production expenses are
        incurred by Pioneer USA and billed to the Partnership. The majority of
        the Partnership's oil and gas revenues are received directly by the
        Partnership, however, a portion of the oil and gas revenue is initially
        received by Pioneer USA prior to being paid to the Partnership.

        Limited partner liability - The maximum amount of liability of any
        limited partner is the total contributions of such partner plus his
        share of any undistributed profits.

        Initial capital contributions - The limited partners entered into
        subscription agreements for aggregate capital contributions of
        $12,252,000. The general partners are required to contribute amounts
        equal to 10% of Partnership expenditures for lease acquisition, drilling
        and completion and 25% of direct, general and administrative and
        operating expenses.

ITEM 9. CHANGES IN AND DISAGREEMENTS WITH ACCOUNTANTS ON ACCOUNTING AND
         FINANCIAL DISCLOSURE

None.


                                       20
   240

                                    PART III

ITEM 10. DIRECTORS AND EXECUTIVE OFFICERS OF THE PARTNERSHIP

The Partnership does not have any officers or directors. Under the limited
partnership agreement, the Partnership's managing general partner, Pioneer USA,
is granted the exclusive right and full authority to manage, control and
administer the Partnership's business.

Set forth below are the names, ages and positions of the directors and executive
officers of Pioneer USA. Directors of Pioneer USA are elected to serve until the
next annual meeting of stockholders or until their successors are elected and
qualified.



                               Age at
                            December 31,
      Name                      2000                      Position
      ----                      ----                      --------
                                           
Scott D. Sheffield               48              President

Timothy L. Dove                  44              Executive Vice President, Chief
                                                   Financial Officer and Director

Dennis E. Fagerstone             51              Executive Vice President and Director

Mark L. Withrow                  53              Executive Vice President, General
                                                   Counsel and Director

Danny Kellum                     46              Executive Vice President - Domestic
                                                   Operations and Director

Rich Dealy                       34              Vice President and Chief Accounting
                                                   Officer


        Scott D. Sheffield. Mr. Sheffield is a graduate of The University of
Texas with a B.S. in Petroleum Engineering. Since August 1997, he has served as
President, Chief Executive Officer and a director of Pioneer and President of
Pioneer USA. Mr. Sheffield assumed the position of Chairman of the Board of
Pioneer in August 1999. He served as a director of Pioneer USA from August 1997
until his resignation from the board in June 1999. Mr. Sheffield was the
President and a director of Parker & Parsley Petroleum Company ("Parker &
Parsley") from May 1990 until August 1997 and was the Chairman of the Board and
Chief Executive Officer of Parker & Parsley from October 1990 until August 1997.
He was the sole director of Parker & Parsley from May 1990 until October 1990.
Mr. Sheffield joined Parker & Parsley Development Company ("PPDC"), a
predecessor of Parker & Parsley, as a petroleum engineer in 1979. He served as
Vice President - Engineering of PPDC from September 1981 until April 1985 when
he was elected President and a director. In March 1989, Mr. Sheffield was
elected Chairman of the Board and Chief Executive Officer of PPDC. Before
joining PPDC's predecessor, Mr. Sheffield was employed as a production and
reservoir engineer for Amoco Production Company.


                                       21
   241

        Timothy L. Dove. Mr. Dove earned a B.S. in Mechanical Engineering from
Massachusetts Institute of Technology in 1979 and received his M.B.A. in 1981
from the University of Chicago. He became Executive Vice President - Business
Development of Pioneer and Pioneer USA in August 1997 and was also appointed a
director of Pioneer USA in August 1997. Mr. Dove assumed the position of Chief
Financial Officer of Pioneer and Pioneer USA effective February 1, 2000. Mr.
Dove joined Parker & Parsley in May 1994 as Vice President - International and
was promoted to Senior Vice President - Business Development in October 1996, in
which position he served until August 1997. Prior to joining Parker & Parsley,
Mr. Dove was employed with Diamond Shamrock Corp., and its successor, Maxus
Energy Corp, in various capacities in international exploration and production,
marketing, refining and marketing and planning and development.

        Dennis E. Fagerstone. Mr. Fagerstone, a graduate of the Colorado School
of Mines with a B.S. in Petroleum Engineering, became an Executive Vice
President of Pioneer and Pioneer USA in August 1997. He was also appointed a
director of Pioneer USA in August 1997. He served as Executive Vice President
and Chief Operating Officer of MESA Inc. ("Mesa") from March 1, 1997 until
August 1997. From October 1996 to February 1997, Mr. Fagerstone served as Senior
Vice President and Chief Operating Officer of Mesa and from May 1991 to October
1996, he served as Vice President - Exploration and Production of Mesa. From
June 1988 to May 1991, Mr. Fagerstone served as Vice President - Operations of
Mesa.

        Mark L. Withrow. Mr. Withrow, a graduate of Abilene Christian University
with a B. S. in Accounting and Texas Tech University with a Juris Doctorate
degree, became Executive Vice President, General Counsel and Secretary of
Pioneer and Pioneer USA in August 1997. He was also appointed a director of
Pioneer USA in August 1997. Mr. Withrow was Vice President - General Counsel of
Parker & Parsley from January 1991, when he joined Parker & Parsley, to January
1995, when he was appointed Senior Vice President - General Counsel. He was
Parker & Parsley's Secretary from August 1992 until August 1997. Prior to
joining Parker & Parsley, Mr. Withrow was the managing partner of the law firm
of Turpin, Smith, Dyer, Saxe & MacDonald, Midland, Texas.

        Danny Kellum. Mr. Kellum, who received a Bachelor of Science degree in
Petroleum Engineering from Texas Tech University in 1979, was elected Executive
Vice President - Domestic Operations of Pioneer and Pioneer USA on May 18, 2000
and Director of Pioneer USA on February 1, 2000. From January 2000 until May
2000, Mr. Kellum served as Vice President - Domestic Operations of Pioneer and
Pioneer USA. Mr. Kellum served as Vice President Permian Division of Pioneer and
Pioneer USA from April 1998 until December 1999. From 1989 until 1994 he served
as Spraberry District Manager and as Vice President of the Spraberry and Permian
Division for Parker & Parsley until August of 1997. Mr. Kellum joined Parker &
Parsley as an operations engineer in 1981 after a brief career with Mobil Oil
Corporation.

        Rich Dealy. Mr. Dealy is a graduate of Eastern New Mexico University
with a B.B.A. in Accounting and Finance and is a Certified Public Accountant. He
became Vice President and Chief Accounting Officer of Pioneer and Pioneer USA in
February 1998. Mr. Dealy served as Controller of Pioneer USA from August 1997 to
February 1998. He served as Controller of Parker & Parsley from August 1995 to
August 1997. Mr. Dealy joined Parker & Parsley as an Accounting Manager in July,
1992. He was previously employed with KPMG Peat Marwick as an Audit Senior, in
charge of Parker & Parsley's audit.


                                       22
   242

ITEM 11. EXECUTIVE COMPENSATION

The Partnership does not have any directors or officers. Management of the
Partnership is performed by Pioneer USA, the managing general partner. Under the
Partnership agreement, Pioneer USA pays 8% of the Partnership's acquisition,
drilling and completion costs and 20% of its operating and general and
administrative expenses. In return, Pioneer USA is allocated 20% of the
Partnership's revenues.

EMPL is a co-general partner of the Partnership. Under this arrangement, EMPL
pays 2% of the Partnership's acquisition, drilling and completion costs and 5%
of its operating and general and administrative expenses. In return, EMPL is
allocated 5% of the Partnership's revenues. EMPL does not receive any fees or
reimbursements from the Partnership.

The Partnership does not directly pay any salaries of the executive officers of
Pioneer USA, but does pay a portion of Pioneer USA's general and administrative
expenses of which these salaries are a part.

See Notes 6 and 9 of Notes to Financial Statements included in "Item 8.
Financial Statements and Supplementary Data" for information regarding fees and
reimbursements paid to the managing general partner by the Partnership.

ITEM 12. SECURITY OWNERSHIP OF CERTAIN BENEFICIAL OWNERS AND MANAGEMENT

(a) Beneficial owners of more than five percent

The Partnership is not aware of any person who beneficially owns 5% or more of
the outstanding limited partnership interests of the Partnership. Pioneer USA
and EMPL respectively own 80% and 20% of the general partners' interests in the
Partnership. Pioneer USA owned 226 limited partner interests at January 1, 2001.

(b) Security ownership of management

The Partnership does not have any officers or directors. The managing general
partner of the Partnership, Pioneer USA, has the exclusive right and full
authority to manage, control and administer the Partnership's business. Under
the limited partnership agreement, limited partners holding a majority of the
outstanding limited partnership interests have the right to take certain
actions, including the removal of the managing general partner or any other
general partner. The Partnership is not aware of any current arrangement or
activity which may lead to such removal. The Partnership is not aware of any
officer or director of Pioneer USA who beneficially owns limited partnership
interests in the Partnership.


                                       23
   243

ITEM 13. CERTAIN RELATIONSHIPS AND RELATED TRANSACTIONS

Transactions with the managing general partner

Pursuant to the limited partnership agreement, the Partnership had the following
related party transactions with the general partners during the years ended
December 31:



                                                     2000         1999         1998
                                                   ---------    ---------    --------
                                                                    
   Payment of lease operating and supervision
     charges in accordance with standard
     industry operating agreements                 $ 143,855    $ 139,170    $133,844

   Reimbursement of general and administrative
     expenses                                      $  21,928    $  14,326    $ 11,397


Under the limited partnership agreement, the general partners, Pioneer USA and
EMPL, together pay 10% of the Partnership's acquisition, drilling and completion
costs and 25% of its operating and general and administrative expenses. In
return, they are allocated 25% of the Partnership's revenues. Twenty percent of
the general partner's share of costs and revenues is allocated to EMPL and the
remainder is allocated to Pioneer USA. Certain former affiliates of the managing
general partner are limited partners of EMPL. Also, see Notes 6 and 9 of Notes
to Financial Statements included in "Item 8. Financial Statements and
Supplementary Data", regarding the Partnership's participation with the managing
general partner in oil and gas activities of the Partnership.


                                       24
   244

                                     PART IV


ITEM 14. EXHIBITS, FINANCIAL STATEMENT SCHEDULES AND REPORTS ON FORM 8-K

(a)   1.   Financial statements

           The following are filed as part of this Report:

                Independent Auditors' Report

                Balance sheets as of December 31, 2000 and 1999

                Statements of operations for the years ended December 31, 2000,
                  1999 and 1998

                Statements of partners' capital for the years ended December 31,
                  2000, 1999 and 1998

                Statements of cash flows for the years ended December 31, 2000,
                  1999 and 1998

                Notes to financial statements

      2.   Financial statement schedules

           All financial statement schedules have been omitted since the
           required information is in the financial statements or notes thereto,
           or is not applicable nor required.

(b)   Reports on Form 8-K

None.

(c)   Exhibits

      The exhibits listed on the accompanying index to exhibits are filed or
      incorporated by reference as part of this Report.


                                       25
   245

                               S I G N A T U R E S

        Pursuant to the requirements of the Securities Exchange Act of 1934, the
Registrant has duly caused this Report to be signed on its behalf by the
undersigned, thereunto duly authorized.

                                    PARKER & PARSLEY 82-II, LTD.

Dated: March 23, 2001               By:   Pioneer Natural Resources USA, Inc.
                                            Managing General Partner


                                          By:   /s/ Scott D. Sheffield
                                                --------------------------------
                                                Scott D. Sheffield, President

        Pursuant to the requirements of the Securities Exchange Act of 1934,
this Report has been signed below by the following persons on behalf of the
Registrant and in the capacities and on the date indicated.



                                                                        
/s/ Scott D. Sheffield              President of Pioneer USA                  March 23, 2001
-------------------------------
Scott D. Sheffield


/s/ Timothy L. Dove                 Executive Vice President, Chief           March 23, 2001
-------------------------------     Financial Officer and Director of
Timothy L. Dove                     Pioneer USA


/s/ Dennis E. Fagerstone            Executive Vice President and              March 23, 2001
-------------------------------     Director of Pioneer USA
Dennis E. Fagerstone


/s/ Mark L. Withrow                 Executive Vice President, General         March 23, 2001
-------------------------------     Counsel and Director of Pioneer USA
Mark L. Withrow


/s/ Danny Kellum                    Executive Vice President - Domestic       March 23, 2001
-------------------------------     Operations and Director of Pioneer
Danny Kellum                        USA


/s/ Rich Dealy                      Vice President and Chief Accounting       March 23, 2001
-------------------------------     Officer of Pioneer USA
Rich Dealy



                                       26
   246

                          PARKER & PARSLEY 82-II, LTD.

                                INDEX TO EXHIBITS

        The following documents are incorporated by reference in response to
Item 14(c):



Exhibit No.                             Description                              Page
-----------                             -----------                              ----
                                                                           
       3.1                Agreement of Limited Partnership of                       -
                          Parker & Parsley 82-II, Ltd. incorporated
                          by reference to Exhibit 4(e) of Partnership's
                          Registration Statement on Form S-1
                          (Registration No. 2-75503B), as amended
                          on February 4, 1982, the effective date
                          thereof (hereinafter called, the Partnership's
                          Registration Statement)

       3.2                Amended and Restated Certificate of                       -
                          Limited Partnership of Parker & Parsley
                          82-II, Ltd. incorporated by reference to
                          Exhibit 3.2 of the Partnership's Annual
                          Report on Form 10-K for the year ended
                          December 31, 1983

       4.1                Form of Subscription Agreement and Power                  -
                          of Attorney incorporated by reference to
                          Exhibit 4(b) of the Partnership's Registration
                          Statement

       4.2                Specimen Certificate of Limited Partnership               -
                          Interest incorporated by reference to Exhibit
                          4(d) of the Partnership's Registration Statement



                                       27
   247
                          PARKER & PARSLEY 82-II, LTD.

SELECTED FINANCIAL DATA

The following selected financial data for the Partnership should be read in
connection with Management's Discussion and Analysis of Financial Condition and
Results of Operations and the financial statements included in the attached
supplemental information.



                                       Three months
                                           ended
                                         March 31,                              Years ended December 31,
                                    ---------------------   --------------------------------------------------------------
                                      2001        2000         2000         1999         1998         1997          1996
                                    --------   ----------   ----------   ----------   ----------   ----------   ----------
                                                                                           

Operating results:
  Oil and gas sales                 $          $  165,410   $  730,936   $  477,533   $  379,887   $  598,339   $  732,599
                                    ========   ==========   ==========   ==========   ==========   ==========   ==========

  Gain on litigation
    settlement, net                 $     --   $       --   $       --   $       --   $       --   $       --   $   45,027
                                    ========   ==========   ==========   ==========   ==========   ==========   ==========

  Impairment of oil and gas
    properties                      $          $       --   $       --   $       --   $   65,229   $  310,732   $       --
                                    ========   ==========   ==========   ==========   ==========   ==========   ==========

  Net income (loss)                 $          $   74,521   $  350,536   $  120,353   $ (131,488)  $  (93,386)  $  322,918
                                    ========   ==========   ==========   ==========   ==========   ==========   ==========

  Allocation of net income
    (loss):
        General partner             $          $   20,457   $   94,215   $   38,680   $    2,863   $   30,221   $   98,377
                                    ========   ==========   ==========   ==========   ==========   ==========   ==========

        Limited partners            $          $   54,064   $  256,321   $   81,673   $ (134,351)  $ (123,607)  $  224,541
                                    ========   ==========   ==========   ==========   ==========   ==========   ==========

  Limited partners' net
    income (loss) per limited
    partnership interest            $          $     8.83   $    41.84   $    13.33   $   (21.93)  $   (20.18)  $    36.65
                                    ========   ==========   ==========   ==========   ==========   ==========   ==========

  Limited partners' cash
    distributions per limited
    partnership interest            $          $     9.95   $    44.08   $    15.29   $   (46.67)  $    43.00   $    49.38(a)
                                    ========   ==========   ==========   ==========   ==========   ==========   ==========

At year end:
  Identifiable assets               $          $  966,117   $  960,300   $  971,351   $  971,390   $1,456,326   $1,893,741
                                    ========   ==========   ==========   ==========   ==========   ==========   ==========


----------

(a)  Including litigation settlement per limited partnership interest of $6.02
     in 1996.

   248
                        PIONEER NATURAL RESOURCES COMPANY
                       PIONEER NATURAL RESOURCES USA, INC.
                            1400 WILLIAMS SQUARE WEST
                            5205 NORTH O'CONNOR BLVD.
                               IRVING, TEXAS 75039

                            SUPPLEMENTAL INFORMATION

                                       OF

           PARKER & PARSLEY 82-III, LTD., A TEXAS LIMITED PARTNERSHIP

                                       TO

                PROXY STATEMENT/PROSPECTUS DATED      , 2001

                                   ----------

                 THE DATE OF THIS SUPPLEMENT IS      , 2001

                                   ----------

     This document contains important information specific to Parker & Parsley
82-III, Ltd. and supplements the proxy statement/prospectus dated     , 2001, of
Pioneer Natural Resources Company and Pioneer Natural Resources USA, Inc., by
which Pioneer USA is soliciting proxies to be voted at a special meeting of
limited partners of the partnership. The purpose of the special meeting is for
you to vote upon the merger of the partnership with and into Pioneer USA that,
if completed, will result in your receiving common stock of Pioneer Natural
Resources Company and cash for your partnership interests.

     This document contains the following information concerning Parker &
Parsley 82-III, Ltd.:

     o    A table containing:

          --   the aggregate initial investment by the limited partners

          --   the aggregate historical limited partner distributions through
               March 31, 2001

          --   the aggregate merger value attributable to partnership interests
               of limited partners, excluding Pioneer USA

          --   the merger value per $1,000 limited partner investment as of
               March 31, 2001

          --   the merger value per $1,000 limited partner investment as a
               multiple of distributions for the 12 months ended March 31, 2001

          --   the book value per $1,000 limited partner investment as of March
               31, 2001 and as of December 31, 2000

          --   the going concern value per $1,000 limited partner investment as
               of March 31, 2001

          --   the liquidation value per $1,000 limited partner investment as of
               March 31, 2001

          --   the ordinary tax loss per $1,000 limited partner investment in
               year of initial investment

     o    Information about the legal opinion for the limited partners

     o    The partnership's financial statements, including management's
          discussion and analysis of financial condition and results of
          operations, for the three months ended March 31, 2001

     o    The partnership's financial statements, including management's
          discussion and analysis of financial condition and results of
          operations, for the year ended December 31, 2000

     o    Selected historical financial data for the partnership for the three
          months ended March 31, 2001 and 2000 and the five years ended December
          31, 2000


                                      -1-
   249


                          PARKER & PARSLEY 82-III, LTD.

                         SUPPLEMENTAL INFORMATION TABLE


                                                                                          
Aggregate Initial Investment by the Limited Partners(a)                                      $   6,882

Aggregate Historical Limited Partner Distributions through March 31, 2001(a)                 $   6,657

Aggregate  Merger  Value  Attributable  to  Partnership  Interests  of  Limited  Partners,   $     777
Excluding Pioneer USA(a)

Merger Value per $1,000 Limited Partner Investment as of March 31, 2001(b)                   $  120.01

Merger Value per $1,000 Limited Partner  Investment as a Multiple of Distributions for the        3.37 times
12 Months ended March 31, 2001(b)

Book Value per $1,000 Limited Partner Investment:

          --   as of March 31, 2001(b)                                                       $

          --   as of December 31, 2000(b)                                                    $   55.84

Going Concern Value per $1,000 Limited Partner Investment as of March 31, 2001(b)            $  107.25

Liquidation Value per $1,000 Limited Partner Investment as of March 31, 2001(b)              $  116.79

Ordinary Tax Loss per $1,000  Limited  Partner  Investment  in Year of Initial  Investment   $     220
(b), (c)

-----------

(a)  Stated in thousands.

(b)  Interests in some partnerships were sold in units at prices other than
     $1,000. We have presented this information based on a $1,000 initial
     investment for ease of use and comparison among partnerships. You should
     not assume that the amount shown per $1,000 investment is the same as the
     value or amount attributable to a single unit investment.

(c)  Your ability to use your distributive share of the partnership's loss to
     offset your other income may have been subject to certain limitations at
     your level as a partner, and you may therefore wish to consult your tax
     advisor to determine the additional value, if any, actually realized by you
     in your particular circumstances.



          INFORMATION ABOUT THE LEGAL OPINION FOR THE LIMITED PARTNERS

     The partnership agreement for the partnership requires that special legal
counsel render an opinion on behalf of the limited partners to Pioneer USA that
(1) neither the grant nor the exercise of the right to approve the merger of the
partnership by its limited partners will adversely affect the federal income tax
classification of the partnership or any of its limited partners; and (2)
neither the grant nor exercise of such right will result in the loss of any
limited partner's limited liability. In addition, the counsel designated to
render the opinion must be counsel other than counsel to Pioneer USA or the
partnership. Both the designated counsel and the legal opinion must be approved
by the limited partners. Pioneer USA has retained __________ of Dallas, Texas
for the purpose of rendering this legal opinion on behalf of the limited
partners to Pioneer USA. The merger proposals include an approval of that
counsel and the form of its opinion. A copy of the opinion is attached as an
exhibit to the merger proposals.


                                      -2-
   250




                          PARKER & PARSLEY 82-III, LTD.
                          (A Texas Limited Partnership)


                              FINANCIAL STATEMENTS
                                      WITH
                          INDEPENDENT AUDITORS' REPORT


                           December 31, 2000 and 1999



   251



                          INDEPENDENT AUDITORS' REPORT



The Partners
Parker & Parsley 82-III, Ltd.
  (A Texas Limited Partnership):

We have audited the balance sheets of Parker & Parsley 82-III, Ltd. as of
December 31, 2000 and 1999, and the related statements of operations, partners'
capital and cash flows for each of the three years in the period ended December
31, 2000. These financial statements are the responsibility of the Partnership's
management. Our responsibility is to express an opinion on these financial
statements based on our audits.

We conducted our audits in accordance with auditing standards generally accepted
in the United States. Those standards require that we plan and perform the audit
to obtain reasonable assurance about whether the financial statements are free
of material misstatement. An audit includes examining, on a test basis, evidence
supporting the amounts and disclosures in the financial statements. An audit
also includes assessing the accounting principles used and significant estimates
made by management, as well as evaluating the overall financial statement
presentation. We believe that our audits provide a reasonable basis for our
opinion.

In our opinion, the financial statements referred to above present fairly, in
all material respects, the financial position of Parker & Parsley 82-III, Ltd.
as of December 31, 2000 and 1999, and the results of its operations and its cash
flows for each of the three years in the period ended December 31, 2000, in
conformity with accounting principles generally accepted in the United States.




                                           Ernst & Young LLP


Dallas, Texas
March 9, 2001



                                       2
   252



                          PARKER & PARSLEY 82-III, LTD.
                          (A Texas Limited Partnership)

                                 BALANCE SHEETS
                                   December 31






                                                          2000        1999
                                                        -------     -------
           ASSETS

                                                           
Current assets:
  Cash                                                $  46,188   $  53,335
  Accounts receivable  - oil and gas sales               69,903      47,611
                                                        -------     -------

      Total current assets                              116,091     100,946
                                                        -------     -------

Oil and gas properties - at cost, based on the
  successful efforts accounting method                5,970,397   5,967,913
Accumulated depletion                                (5,634,468) (5,611,986)

      Net oil and gas properties                        335,929     355,927
                                                        -------     -------

                                                      $ 452,020   $ 456,873
                                                       ========    ========

LIABILITIES AND PARTNERS' CAPITAL

Current liabilities:
  Accounts payable - affiliate                        $   9,780   $  11,302

Partners' capital:
  General partners                                       57,956      54,214
  Limited partners (3,441 interests)                    384,284     391,357
                                                        -------     -------

                                                        442,240     445,571

                                                      $ 452,020   $ 456,873
                                                       ========    ========



   The accompanying notes are an integral part of these financial statements.



                                       3
   253



                          PARKER & PARSLEY 82-III, LTD.
                          (A Texas Limited Partnership)

                            STATEMENTS OF OPERATIONS
                         For the years ended December 31






                                              2000        1999       1998
                                           ---------    --------   ---------

                                                          
Revenues:
  Oil and gas                             $ 562,399   $ 340,246  $  253,873
  Interest                                    4,310       2,124       3,120
  Gain on disposition of assets                 -         1,922         634
                                            -------     ------     --------

                                            566,709     344,292     257,627
                                            -------     ------     --------

Costs and expenses:
  Oil and gas production                    222,803     198,571     202,485
  General and administrative                 19,194      14,161       9,538
  Impairment of oil and gas properties          -           -       277,671
  Depletion                                  22,482      46,605     252,951
                                            -------      ------    --------

                                            264,479     259,337     742,645
                                            -------     -------    --------

Net income (loss)                         $ 302,230   $  84,955  $ (485,018)
                                            =======      ======    ========

Allocation of net income (loss):
  General partners                        $  78,705   $ 27,431   $  (41,756)
                                            =======     ======     ========

  Limited partners                        $ 223,525   $ 57,524   $ (443,262)
                                            =======     ======     ========

Net income (loss) per limited
  partnership interest                     $  64.96    $ 16.72   $  (128.82)
                                            =======     ======     ========






   The accompanying notes are an integral part of these financial statements.



                                       4
   254



                          PARKER & PARSLEY 82-III, LTD.
                          (A Texas Limited Partnership)

                         STATEMENTS OF PARTNERS' CAPITAL






                                            General      Limited