EXHIBIT 99.2

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                               PRODUCTION PAYMENT
                           PURCHASE AND SALE AGREEMENT


                                     between


                       PIONEER NATURAL RESOURCES USA, INC.
                                       AND
                     PIONEER NATURAL RESOURCES PROPERTIES LP


                                   as Seller,


                                       and


                           WOLFCAMP OIL AND GAS TRUST

                           a Delaware Statutory Trust

                                    as Buyer




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


                           Dated as of April 18, 2005

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                                TABLE OF CONTENTS

                                                                         Page



ARTICLE I DEFINITIONS AND REFERENCES......................................1
         SECTION 1.01.     Definitions....................................1
         SECTION 1.02.     References, Gender, Number.....................6

ARTICLE II SALE AND PURCHASE..............................................7

ARTICLE III CONSIDERATION AND PAYMENT.....................................7
         SECTION 3.01.     Consideration and Purchase Price...............7
         SECTION 3.02.     Payment Instructions...........................7

ARTICLE IV REPRESENTATIONS AND WARRANTIES.................................7
         SECTION 4.01.     Representations and Warranties of Seller.......7
         SECTION 4.02.     Representations and Warranties of Buyer.......13

ARTICLE V COVENANTS OF SELLER AND BUYER..................................14
         SECTION 5.01.     Confidentiality and Public Announcements......14
         SECTION 5.02.     Survival Past Closing.........................14
         SECTION 5.03.     Reasonable Cooperation........................14
         SECTION 5.04.     Preference Rights.............................15

ARTICLE VI CLOSING CONDITIONS............................................15
         SECTION 6.01.     Seller's Closing Conditions...................15
         SECTION 6.02.     Buyer's Closing Conditions....................15

ARTICLE VII CLOSING......................................................17
         SECTION 7.01.     Closing.......................................17
         SECTION 7.02.     Seller's Closing Obligations..................17
         SECTION 7.03.     Buyer's Closing Obligations...................17

ARTICLE VIII ASSUMPTION AND INDEMNIFICATION..............................17
         SECTION 8.01.     Covered Liabilities...........................17
         SECTION 8.02.     Indemnification by Seller.....................18
         SECTION 8.03.     Third Party Claims............................19

ARTICLE IX MISCELLANEOUS.................................................19
         SECTION 9.01.     Counterparts..................................19
         SECTION 9.02.     Governing Law; Consent to Jurisdiction........20
         SECTION 9.03.     WAIVER OF JURY TRIAL..........................20
         SECTION 9.04.     Entire Agreement..............................21
         SECTION 9.05.     Each Party Pays Own Expenses..................21
         SECTION 9.06.     Notices.......................................21
         SECTION 9.07.     Successors and Assigns........................21
         SECTION 9.08.     Headings......................................23
         SECTION 9.09.     Amendments and Waivers........................23
         SECTION 9.10.     Schedules and Exhibits........................23
         SECTION 9.11.     Interpretation................................23
         SECTION 9.12.     Agreement for the Parties' Benefit Only.......24







                               TABLE OF CONTENTS
                                  (continued)


                                                                        Page

         SECTION 9.13.     Severability..................................24
         SECTION 9.14.     No Retained Liens.............................24
         SECTION 9.15.     Limitations on Damages........................24
         SECTION 9.16.     Tax Treatment.................................25
         SECTION 9.17.     LIMITATION OF OWNER TRUSTEE LIABILITY.........25



                                    SCHEDULES

Schedule 1          -        Wiring Instructions
Schedule 2          -        Insurance
Schedule 3          -        Disclosures



                                       ii








                 PRODUCTION PAYMENT PURCHASE AND SALE AGREEMENT

     THIS PRODUCTION  PAYMENT PURCHASE AND SALE AGREEMENT (herein referred to as
this  "Agreement"),  dated as of April 18, 2005, by and between  Pioneer Natural
Resources  USA,  Inc.,  a Delaware  corporation  and Pioneer  Natural  Resources
Properties  LP, a Delaware  limited  partnership  (herein,  together  with their
successors and permitted assigns, each individually and collectively referred to
as  "Seller"),  and  Wolfcamp  Oil and Gas  Trust,  a Delaware  statutory  trust
(herein,  together with its  successors  and permitted  assigns,  referred to as
"Buyer"),

                                   WITNESSETH:

     WHEREAS,  Seller  intends to sell to Buyer,  and Buyer  intends to purchase
from Seller, in a single transaction, two Production Payments consisting of term
overriding royalty interests carved out of the same mineral properties, upon the
terms and subject to the conditions described herein; and

     WHEREAS,  the purchase price payable hereunder for the Production  Payments
takes into account the estimated  present value of Buyer's future  severance and
ad  valorem  tax  obligations  in  respect  of  the  Production   Payments,   in
consideration  of  Seller's  promise to pay such taxes as they become due in the
future; and

     WHEREAS,  the performance of each  obligation of each Seller  hereunder and
under the Related  Agreements  shall be guaranteed by Pioneer Natural  Resources
Company;

     NOW,  THEREFORE,  in  consideration  of the mutual covenants and agreements
hereinafter set forth, the parties hereto agree as follows:

                                   ARTICLE I
                           DEFINITIONS AND REFERENCES

SECTION 1.01.    Definitions.

     Unless the context otherwise  requires,  each defined term shall be equally
applicable  both to the  singular  and the plural  forms of the term so defined.
When used in this Agreement, the following terms have the following meanings:

     "Action" means any action, claim, suit, arbitration,  inquiry,  proceeding,
investigation,   condemnation   or  audit  by  or  before  any  court  or  other
Governmental Authority or any arbitrator or panel of arbitrators.

     "Affiliate" has the meaning given to such term in the Conveyances.

     "Approved  Investment  Grade" has the meaning given to such term in Section
9.07.

     "Business" means the ownership,  maintenance,  development and operation of
the Subject  Interests and the  gathering,  delivery,  and sale of  Hydrocarbons
produced therefrom.






     "Buyer"  means  Wolfcamp  Oil and Gas Trust,  a Delaware  statutory  trust,
together with its successors and permitted assigns.

     "Buyer  Party"  means  Buyer,  its  trustee  and trust  beneficiaries,  its
lenders,  the Swap Counterparty,  and their respective  successors and permitted
assigns.

     "Cash Purchase Price" has the meaning given to such term in Section 3.01.

     "Closing" means the consummation of the transaction contemplated by Article
VII.

     "Closing  Date" means (a) April 18, 2005,  or (b) such other date as may be
mutually agreed to by Seller and Buyer in writing.

     "Conveyance"  means either the Oil Conveyance or the Methane Conveyance and
"Conveyances" means both.

     "Covered Liabilities" has the meaning given to such term in Section 8.01.

     "Defensible  Title"  means  such  title as  enables  Seller  to  correctly,
accurately  and  truthfully  make the  representations  in  Section  6.3 of each
Conveyance.

     "Delivery  Points"  has the  meaning  given to such term in the  applicable
Conveyance.

     "Environmental  Laws"  means  all Laws that  relate to (a) the  prevention,
abatement or elimination of pollution,  or the protection of the  environment or
natural resources, (b) the generation,  handling,  treatment, storage, disposal,
release or  transportation  of waste materials or hazardous or toxic substances,
or (c) the  regulation  of or exposure to hazardous,  toxic or other  substances
alleged to be  harmful,  including  the  Comprehensive  Environmental  Response,
Compensation  and  Liability  Act, 42 U.S.C.  ss.  9601,  et seq.;  the Resource
Conservation  and Recovery  Act, 42 U.S.C.  ss. 6901 et seq.;  the Federal Water
Pollution  Control Act (Clean Water Act), 33 U.S.C. ss. 1251, et seq.; the Clean
Air Act, 42 U.S.C.  ss. 7401, et seq.;  the Hazardous  Materials  Transportation
Act, 49 U.S.C.  ss. 1471, et seq.; the Toxic  Substances  Control Act, 15 U.S.C.
ss.  2601,  et seq.;  the Oil  Pollution  Act, 33 U.S.C.  ss. 2701 et seq.;  the
Emergency  Planning and Community  Right-to-Know  Act, 42 U.S.C.  ss. 11001,  et
seq.; the Safe Drinking Water Act, 42 U.S.C.  ss.ss.  300f through 300j; and the
Endangered Species Act, 16 U.S.C. ss. 1531, et seq.; and all similar Laws of any
Governmental Authority having jurisdiction over the property in question.

     "Gas" has the meaning given to such term in the Methane Conveyance.

     "Governmental  Authority"  has  the  meaning  given  to  such  term  in the
Conveyances.

     "Guarantor" means Pioneer,  its permitted  successors and assigns under the
Pioneer Guaranty.

     "Hazardous  Materials"  means (a) any substance or material that is listed,
defined or otherwise designated as a "toxic substance," "hazardous substance" or
"hazardous waste" under any Environmental  Law, including Section 101(14) of the
Comprehensive  Environmental  Response,  Compensation and Liability Act, (b) any

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radioactive  material,  asbestos or polychlorinated  biphenyls and (c) any other
chemical, substance or waste that is regulated under any Environmental Law.

     "Hydrocarbons" means, collectively, Oil and Gas.

     "Imbalance"  means,  without  duplication  but  excluding  each  Production
Payment,  the  sum  (expressed  in  barrels  of Oil or  Mcfs  of Gas) of (a) the
aggregate make-up, prepaid, or other volumes of Oil or Gas that are attributable
to or could burden either  Production  Payment and that Sellers are obligated as
of the Closing Date, on account of prepayment, advance payment, take-or-pay, gas
balancing or similar  obligations,  to deliver from the Subject  Interests after
the  Closing  Date  and  (b),  to the  extent  such  obligations  burden  either
Production  Payment or Buyer could incur any  liability  therefor as a result of
the transaction  contemplated  hereby and the same are not covered by clause (a)
above, the aggregate  pipeline or processing plant imbalances or over deliveries
for which  Seller is  obligated  to pay or deliver  Hydrocarbons  or cash to any
pipeline, gatherer, transporter, processor, co-owner, or purchaser in connection
with any Hydrocarbons attributable to either Production Payment.

     "Indemnified Parties" has the meaning given to such term in Section 8.02.

     "Initial Reserve Report" means the reserve  engineering  report prepared by
Seller's  in-house  engineering  staff as of December 31, 2004, and delivered by
Seller to Buyer prior to and in anticipation of the Closing under a cover letter
dated April 15, 2005.

     "Internal  Revenue  Code"  means  the  Internal  Revenue  Code of 1986,  as
amended,  and any successor thereto,  together with all regulations  promulgated
thereunder.

     The term  "knowledge"  when  used  with  reference  to a  particular  fact,
circumstance  or  condition:  (a) in the case of  either  Seller,  means (i) the
actual  knowledge of any director or officer of such Seller or any  Affiliate of
such Seller or (ii) the actual knowledge of any director, officer or employee of
either Seller or any Affiliate of such Seller  involved in the  negotiation  of,
any analysis or due diligence in connection with this Agreement;  and (b) in the
case of Buyer,  means the actual knowledge of any director,  officer or employee
of  Buyer  or any  Affiliate  of  Buyer  involved  in the  negotiation  of  this
Agreement.

     "Law" means any applicable  statute,  law (including case law),  ordinance,
regulation,  rule, ruling, order,  restriction,  requirement,  writ, injunction,
decree, or other official act of or by any Governmental Authority.

     "Marketing  Agreement"  means  either the Oil  Marketing  Agreement  or the
Methane Marketing Agreement, and "Marketing Agreements" means both.

     "Methane" has the meaning given to such term in the Methane Conveyance.

     "Methane  Conveyance"  means  the  Conveyance  of Term  Overriding  Royalty
Interest  of even date  herewith  from  Seller  to Buyer  that is  executed  and
delivered at the Closing,  under which the Subject  Hydrocarbons  are limited to
Methane.

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     "Methane  Marketing  Agreement" means the Marketing  Agreement of even date
herewith  between  Pioneer USA and Buyer that is executed  and  delivered at the
Closing with respect to Methane accruing to the Methane Production Payment.

     "Methane Production  Payment" means the "Production  Payment" as defined in
the Methane Conveyance.

     "Month" means the one-month period beginning at 9:00 a.m., Central Time, on
the first day of a calendar month and ending at 9:00 a.m.,  Central Time, on the
first day of the following calendar month.

     "Moody's"  means Moody's  Investors  Service,  Inc. or any successor to its
credit rating business.

     "Net  Revenue  Interest"  has  the  meaning  given  to  such  term  in each
Conveyance, as applicable.

     "Novation Agreement" means the Novation  Confirmation of even date herewith
among  Buyer,  Pioneer  USA and the  Swap  Counterparty  that  is  executed  and
delivered at the Closing.

     "Oil" has the meaning given to such term in the Oil Conveyance.

     "Oil Conveyance"  means the Conveyance of Term Overriding  Royalty Interest
of even date herewith from Seller to Buyer that is executed and delivered at the
Closing, under which the Subject Hydrocarbons are limited to Oil.

     "Oil  Marketing  Agreement"  means  the  Marketing  Agreement  of even date
herewith  between  Pioneer USA and Buyer that is executed  and  delivered at the
Closing with respect to Oil accruing to the Oil Production Payment.

     "Oil Production  Payment" means the "Production  Payment" as defined in the
Oil Conveyance.

     "PDNP Reserves" means proved,  developed,  non-producing reserves of Gas or
Oil.

     "PDP Reserves" means proved, developed, producing reserves of Gas or Oil.

     "Permits" means all licenses,  permits,  certificates,  orders,  approvals,
franchises,   exemptions,   variances,   waivers  and   authorizations   of  any
Governmental Authority,  including applications therefor,  necessary or required
to own and  operate  (to the  extent  operated  by either  Seller)  the  Subject
Interests and conduct the Business  (including  those required by  Environmental
Laws).

     "Permitted  Encumbrances"  has  the  meaning  given  to  such  term in each
Conveyance, as applicable.

     "Person"  means  any  Governmental  Authority  or  any  individual,   firm,
partnership,  corporation, joint venture, trust, unincorporated organization, or
other entity or organization.


                                       4






     "Petroleum  Engineer" means Netherland,  Sewell & Associates,  Inc. and any
other nationally  recognized  reserve  engineering firm that audits Sellers' oil
and gas reserves for Securities and Exchange Commission reporting purposes.

     "Pioneer" means Pioneer Natural Resources Company.

     "Pioneer Guaranty" means the Guaranty of even date herewith from Pioneer to
Buyer that is executed and delivered at the Closing.

     "Pioneer LP" means  Pioneer  Natural  Resources  Properties  LP, a Delaware
limited partnership.

     "Pioneer  USA"  means  Pioneer  Natural  Resources  USA,  Inc.,  a Delaware
corporation.

     "Preference  Right" means any right or agreement that enables or may enable
any Person to purchase or acquire any Subject  Interest or any interest  therein
or portion thereof as a result of the conveyance, sale, assignment,  mortgage or
other transfer of either  Production  Payment or any interest therein or portion
thereof.

     "Production Payment" means either the Oil Production Payment or the Methane
Production Payment, and "Production Payments" means both.

     "Production  Payment  Documents"  means  this  Agreement  and  the  Related
Agreements.

     "Production Payment Hydrocarbons" has the meaning given to such term in the
applicable Conveyance.

     "Production  Purchaser" and  "Production  Sales Contract" have the meanings
given to such terms in the applicable Marketing Agreement.

     "PUD Reserves" means proved, undeveloped reserves of Gas or Oil.

     "Related Agreements" means the Conveyances,  the Marketing Agreements,  the
Pioneer Guaranty and the Novation Agreement.

     "S&P" means Standard and Poor's,  a division of the McGraw-Hill  Companies,
or any successor to its credit rating business.

     "Scheduled  Quantity" has the meaning given to such term in the  applicable
Conveyance.

     "Seller"  refers  collectively  to Pioneer  Natural  Resources  USA,  Inc.,
Pioneer Natural  Resources  Properties LP, and their  respective  successors and
permitted assigns.  As used herein,  terms such as "each Seller",  "any Seller",
"either  Seller",  "neither  Seller",  and "such  Seller"  refer to the  various
individual Persons that collectively make up "Seller".

     "Subject Hydrocarbons" has the meaning given to such term in the applicable
Conveyance.

                                       5





     "Subject  Interests"  has the meaning given to such term in the  applicable
Conveyance.

     "Subject  Wells"  has the  meaning  given  to such  term in the  applicable
Conveyance.

     "Swap Counterparty" means Barclays Bank PLC.

     "Taxes" has the meaning given to such term in the applicable Conveyance.

     "Title  Failure"  means a breach  of any of  Seller's  representations  and
warranties in Section 6.3 of the applicable Conveyance shall have occurred.

     "Transfer Requirement" means any consent, approval, authorization or permit
of, or filing with or notification  to, any Person which must be obtained,  made
or complied with for or in connection  with the conveyance of either  Production
Payment or any portion thereof in order (a) for such conveyance to be effective,
(b) to prevent any termination,  cancellation,  default, acceleration, or change
in terms (or any right thereof from  arising)  under any terms,  conditions,  or
provisions  of  any  Subject  Interest  (or  of any  agreement,  instrument,  or
obligation  relating to or burdening  any Subject  Interest) as a result of such
conveyance,  or (c) to prevent the creation or imposition  of any lien,  charge,
penalty,  restriction,  security  interest or  encumbrance on or with respect to
either  Production  Payment  or  the  Subject  Interests  as a  result  of  such
conveyance;  provided,  however, that a Preference Right shall not be a Transfer
Requirement.

     "Unqualified Foreign Assignee" means any Person that is organized under the
Laws of a jurisdiction other than the United States,  any State thereof,  or the
District of  Columbia,  unless such  Person (a) is exempt from  withholding  tax
under  applicable  federal and state Laws of the United  States  (including  any
treaty entered into by the United States) with respect to the interest component
of the  Production  Payments  for United  States  federal  and state  income tax
purposes,  and (b) has, at the time or times  prescribed  by  applicable  law or
reasonably requested by Seller,  delivered to Seller such properly completed and
executed documentation  prescribed by applicable Law as will relieve Seller from
any  obligation  to  withhold  and pay taxes to the  United  States or any state
thereof.

SECTION 1.02.    References, Gender, Number.

     All references in this Agreement to an "Article," "Section,"  "Subsection,"
"Exhibit,"  or  "Schedule"  shall  be to  the  specified  Article,  Section,  or
Subsection of, or the specified  Exhibit or Schedule to, this Agreement,  unless
the context requires otherwise. Unless the context otherwise requires, the words
"this  Agreement,"  "hereof,"  "hereunder,"  "herein," and "hereby" and words of
similar  import shall refer to this Agreement as a whole and not to a particular
Article, Section, Subsection,  clause, or other subdivision hereof. Whenever the
context requires,  the words used herein shall include the masculine,  feminine,
and neuter  gender,  and the singular and the plural.  Defined terms used herein
not defined herein shall have the meaning provided in the Conveyances.


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                                   ARTICLE II
                                SALE AND PURCHASE

     On the terms and  conditions of this  Agreement,  Seller agrees to sell and
convey  to  Buyer,  and  Buyer  agrees  to  purchase  from  Seller,  both of the
Production Payments.

                                  ARTICLE III
                            CONSIDERATION AND PAYMENT

SECTION 3.01.    Consideration and Purchase Price.

     In consideration  for and concurrently with the sale and conveyance of both
of the  Production  Payments to Buyer,  Buyer shall (a) enter into the  Novation
Agreement in order to assume the liabilities and duties (and acquire the rights)
of Pioneer USA under the hedging transactions  described therein, and (b) pay to
Seller in accordance with the terms hereof the aggregate sum of  $300,402,967.44
(herein referred to as the "Cash Purchase Price").  Each Seller acknowledges and
agrees that the foregoing consideration  constitutes full payment to such Seller
of reasonably  equivalent value for the portions of the Production Payments sold
by such Seller to Buyer pursuant to this Agreement.

SECTION 3.02.    Payment Instructions.

     At the Closing, Buyer shall wire transfer the Purchase Price in immediately
available funds to Seller, as directed in Schedule 1.

                                   ARTICLE IV
                         REPRESENTATIONS AND WARRANTIES

SECTION 4.01.    Representations and Warranties of Seller.

     Pioneer USA and Pioneer LP jointly and  severally  represent and warrant to
Buyer as of the date hereof and as of the Closing Date as follows:

     A.  Organization  and  Qualification.  Pioneer  USA is a  corporation  duly
formed,  validly  existing,  and in good standing under the Laws of the State of
Delaware. Pioneer LP is a limited partnership duly formed, validly existing, and
in good  standing  under the Laws of the State of Delaware.  Each Seller has the
requisite  legal power to carry on its  business  as it is now being  conducted.
Each  Seller is duly  qualified  to do  business,  and is in good  standing,  as
applicable, in each jurisdiction in which it owns any Subject Interests.

     B.  Authority.  Each Seller has all requisite  legal power and authority to
execute,  deliver and perform its  obligations  under this Agreement and each of
the Related  Agreements  to which it is a party.  The  execution,  delivery  and
performance of this  Agreement and each of the Related  Agreements to which such
Seller is a party and the transactions  contemplated hereby or thereby have been
duly and validly authorized by all requisite action on the part of each Seller.

     C.  Enforceability.  This  Agreement  constitutes,  and upon  execution and
delivery  by each  Seller  of each of the  Related  Agreements  to which it is a
party,  each of such Related  Agreements  will  constitute,  a valid and binding


                                       7






agreement of such Seller,  enforceable in accordance with its terms,  subject to
(i) applicable bankruptcy,  insolvency,  reorganization,  moratorium,  and other
similar Laws of general  application  with respect to creditors and (ii) general
principles  of  equity.  Upon  execution  and  delivery  by each  Seller of each
Conveyance  and Buyer's  payment of the Purchase  Price,  each  Conveyance  will
constitute the legal, valid and binding conveyance of the applicable  Production
Payment out of the Subject Interests and each Production Payment will constitute
an interest in real property under applicable state laws owned by Buyer (and not
by either Seller) and a "production  payment" as defined in Section  101(42A) of
the Bankruptcy  Code and referred to in Section  541(b)(4)(B)  of the Bankruptcy
Code.

     D. No Conflict or  Violation.  Neither the  execution  and delivery of this
Agreement or the Related Agreements nor the consummation of the transactions and
performance of the terms and conditions contemplated hereby or thereby by either
Seller or  Guarantor  will (i)  conflict  with or  result  in any  breach of any
provision  of the  articles  of  incorporation  or bylaws,  limited  partnership
agreement (or other similar governing  documents) of either Seller or Guarantor,
as applicable;  (ii) conflict in any material  respect with, or be rendered void
or ineffective in any way that adversely  affects the value of either Production
Payment by, any agreement,  instrument,  or obligation to which either Seller or
Guarantor  is a party  or to  which  either  Seller,  Guarantor  or the  Subject
Interests  are subject;  (iii) subject to the  limitations  contained in Section
4.01C, violate or be rendered void or ineffective under any Law; or (iv) violate
any provision of the Public Utility Holding  Company Act of 1935 ("PUHCA"),  the
Natural Gas Act of 1935 ("NGA"),  the Natural Gas Policy Act of 1978 ("NGPA") or
any of the regulations promulgated under PUHCA, NGA or NGPA.

     E.  Consents.  Except as  disclosed  in Schedule  3, no consent,  approval,
authorization,  or permit  of, or filing  with or  notification  to,  any Person
which, if not obtained or made, would be likely to adversely affect the value of
either Production Payment or would be likely to adversely affect in any material
respect  the use or  operation  of the Subject  Interests  or would be likely to
interfere in any material  respect with the  transactions  contemplated  by this
Agreement or the Related  Agreements,  is required (i) for or in connection with
the execution and delivery of this Agreement or any Related  Agreement by either
Seller or by  Guarantor or for or in  connection  with the  consummation  of the
transactions and performance of the terms and conditions  contemplated hereby or
thereby by either  Seller or  Guarantor,  (ii) in order to prevent any change in
terms, termination, cancellation, default, or acceleration (or any right thereof
from arising) under the terms, conditions, or provisions of any Subject Interest
(or of any  agreement,  instrument,  or obligation  relating to or burdening any
Subject  Interest) as a result of such  execution,  delivery,  consummation,  or
performance,  or (iii) in order to prevent  the  creation or  imposition  of any
lien, charge, penalty, restriction, security interest, or encumbrance on or with
respect to any Subject Interest or either Production Payment as a result of such
execution, delivery, consummation, or performance.

     F.  Preference  Rights and  Transfer  Requirements.  Except as disclosed in
Schedule 3, the Subject  Interests and the Production  Payments are not and will
not be subject  to, and neither  Seller nor any  Affiliate  of either  Seller is
bound by, any  Preference  Rights or Transfer  Requirements  which relate to the
conveyance  of either  Production  Payment to Buyer and which,  if not waived or
satisfied,  would be likely to adversely  affect the value of either  Production


                                       8






Payment  (after taking into account  Buyer's  rights and remedies  under Section
5.04) or would be likely to adversely  affect in any material respect the use or
operation  of the  Subject  Interests  or would be  likely to  interfere  in any
material  respect with the  transactions  contemplated  by this Agreement or the
Related Agreements.

     G.  Actions;  Orders.  Except as  disclosed in Schedule 3: (i) there are no
Actions pending or, to the knowledge of either Seller, threatened which would be
likely to adversely  affect the value of either  Production  Payment or would be
likely to adversely  affect in any material  respect the use or operation of the
Subject  Interests or would be likely to interfere in any material  respect with
the transactions  contemplated by this Agreement or the Related Agreements,  and
(ii) there is no judgment or outstanding  order,  injunction,  decree,  or award
rendered  by any  Governmental  Authority,  arbitrator  or panel of  arbitrators
against  either  Seller  or the  Subject  Interests  which  would be  likely  to
adversely  affect the value of either  Production  Payment or would be likely to
adversely  affect in any  material  respect the use or  operation of the Subject
Interests  or would be likely to  interfere  in any  material  respect  with the
transactions contemplated by this Agreement or the Related Agreements.

     H. Compliance With Laws. Except as disclosed in Schedule 3: (i) the Subject
Interests and the Business are in  compliance in all material  respects with all
Laws,  (ii) neither  Seller has received any notice of any  violation or alleged
violation  (or of any fact or  circumstance  which with notice or the passage of
time or both would constitute a violation) of any Law applicable to the Business
or the Subject  Interests that would be likely to adversely  affect the value of
either Production Payment or would be likely to adversely affect in any material
respect  the use or  operation  of the Subject  Interests  or would be likely to
interfere in any material  respect with the  transactions  contemplated  by this
Agreement  or the  Related  Agreements,  and (iii)  neither  Seller  nor, to the
knowledge of either  Seller,  any prior  operator of the Subject  Interests  has
entered into any currently  existing  compliance or remediation  agreements with
any  Governmental  Authority  or filed any  currently  effective  compliance  or
remediation  plans  with any  Governmental  Authority  which  would be likely to
adversely  affect the value of either  Production  Payment or would be likely to
adversely  affect in any  material  respect the use or  operation of the Subject
Interests  or would be likely to  interfere  in any  material  respect  with the
transactions contemplated by this Agreement or the Related Agreements.

     I.  Permits;  Filings.  Each Seller holds all material  Permits.  Except as
disclosed in Schedule 3, to either Seller's  knowledge:  (i) such Permits are in
full force and effect and all fees and charges  relating thereto have been paid,
(ii) each Seller has in all material  respects and in a timely  manner  complied
with, and operated the Subject  Interests and the Business (to the extent either
Seller  is  the  operator  thereof)  in  accordance  with,  the  conditions  and
provisions  of all such  Permits,  and (iii) no notices of  violation  have been
received by either  Seller or any  Affiliate of Sellers and no  proceedings  are
pending or threatened  that present a material  probability  of resulting in any
modification,  revocation,  termination,  or suspension of any such Permit or of
requiring any material corrective or remediation action with respect thereto. To
the extent required and to the knowledge of each such Seller,  all  applications
for renewal of such Permits have been timely filed.

     J. Compliance With Contracts and Leases. Except as disclosed in Schedule 3,
with respect to all material  contracts,  agreements,  leases,  and arrangements
which are  included  in the  Subject  Interests  or by which any of the  Subject


                                       9





Interests is bound:  (i) to each Seller's  knowledge,  such material  contracts,
agreements,  leases, and arrangements are in full force and effect; (ii) to each
Seller's  knowledge there are no material  violations or breaches thereof and no
existing facts or circumstances which upon notice or the passage of time or both
will constitute a material  violation or breach thereof;  (iii) no notice of the
exercise  or  attempted  exercise of  premature  termination,  price  reduction,
market-out,  or material  curtailment  has been received by either Seller or any
Affiliate  of either  Seller  with  respect  thereto;  (iv) no  notice  has been
received  by either  Seller or any  Affiliate  of either  Seller  that any party
thereto intends not to honor its obligations thereunder;  and (v) neither Seller
is  participating  in any  discussions or  negotiations  regarding  modification
thereof that would be likely to adversely affect the value of either  Production
Payment or would be likely to adversely  affect in any material  respect the use
or  operation  of the Subject  Interests  or would be likely to interfere in any
material  respect with the  transactions  contemplated  by this Agreement or the
Related Agreements.

     K.  Brokerage  Fees and  Commissions.  Neither  Seller nor any Affiliate of
either Seller has incurred any  obligation or entered into any agreement for any
investment banking,  brokerage,  or finder's fee or commission in respect of the
transactions  contemplated by this Agreement or the Related Agreements for which
Buyer shall incur any liability.

     L. Imbalances.  Schedule 3 lists all material Imbalances existing as of the
dates shown on such Schedule,  and such Imbalances have not increased materially
since such dates.

     M. Taxes.  Each Seller has, to its knowledge,  timely paid all Taxes levied
against the Subject Interests, or the production attributable thereto, which are
currently due and payable as required by Law, except for any such Taxes that are
being contested in good faith by appropriate proceedings.

     N.  Initial  Reserve  Report.  Without  limiting  any  of  either  Seller's
obligations under the Related  Agreements,  neither Seller makes any warranty or
representation  as to quantity,  quality,  or  recoverability of the Hydrocarbon
reserves attributable to the Subject Interests, except that each Seller warrants
and represents that (i) Pioneer and its subsidiaries maintain a database for use
in valuing their PDP Reserves, PDNP Reserves and PUD Reserves, which database is
audited by the Petroleum  Engineer in connection with Pioneer's annual financial
statements,  (ii) the production history data and data on operating history that
Pioneer  and its  subsidiaries  include  in such  database  with  respect to the
Subject  Interests and provide to the  Petroleum  Engineer as part of such audit
are true and correct in all material respects, and in providing the same Pioneer
and its subsidiaries did not omit any material information known to them that is
necessary to make such data not  misleading in the context in which so provided,
(iii) the Initial Reserve Report is derived from such database and is consistent
with the conclusions of the Petroleum Engineer in its audit, (iv) the aggregated
net revenue interests included in the Initial Reserve Report with respect to the
Subject  Interests  as a whole  correctly  represent  in all  material  respects
Sellers' Net Revenue  Interests in the various  Subject  Interests,  taking into
account on an aggregate basis any reductions in Sellers' interests due to either
Seller's  failure to consent to proposed  operations and any anticipated  future
reductions in either  Seller's  interests due to the  achievement of payouts and
similar events, (v) to each Seller's knowledge,  substantially all Subject Wells
which were taken into account in the Initial  Reserve  Report were, and continue
to be, producing,  (vi) all such Subject Wells are included in or covered by the
Property  Exhibit  attached to the  Conveyance,  and (vii) the  Initial  Reserve


                                       10






Report does not cover any PDP Reserves, PDNP Reserves or PUD Reserves other than
the PDP  Reserves,  PDNP Reserves and PUD Reserves  attributable  to the Subject
Interests.

     O. Environmental Matters.

        (1) The Subject Interests,  and the operation of the Business are,  and,
to the knowledge of each Seller, at all times have been, in material  compliance
with all applicable  Environmental  Laws,  other than past  violations that have
been settled or corrected and remediated in all material  respects and for which
no material  obligations  remain outstanding except those being performed in the
ordinary course of business.

        (2) To the  knowledge of  Seller,  (i) neither  Seller nor  the  Subject
Interests are subject to any consent decree, compliance order, or administrative
order issued  pursuant to  applicable  Environmental  Laws,  and (ii) except for
routine matters,  Seller has not received any currently  pending written request
for information,  notice of violation,  demand letter,  administrative  inquiry,
complaint or claim from any Governmental Authority pursuant to any Environmental
Law with respect to the Subject Interests.

        (3) To the knowledge  of each  Seller,  the  Subject  Interests  are not
subject to any liens recorded by any  Governmental  Authority  under  applicable
Environmental Laws.

     P. Title.  Each Seller's  representations  and warranties in Section 6.3 of
each  Conveyance are true and correct.  Upon production  thereof,  and also upon
delivery  thereof  at the  Delivery  Points,  Buyer  will have good title to the
Production Payment  Hydrocarbons,  free from any rights of third parties to take
title thereto,  subject only to any applicable  Permitted  Encumbrances.  In the
event Working  Interest  Owner delivers any Gas to Royalty Owner at the Delivery
Points  other  than  Production   Payment   Hydrocarbons   (such  as  deliveries
contemplated  under Section 2.1(b) of the Methane  Conveyance in connection with
bypassing  a  Processing  Plant),  Buyer will have good title to all such Gas so
delivered to Buyer.

     Q. Subject Wells. All currently  existing  producing wells  attributable to
the  Subject  Interests  have been  drilled  and  completed  within  the  limits
permitted by lease,  contract,  pooling,  or unit  agreement  and by Law. To the
knowledge of each Seller,  all  drilling  and  completion  of such wells and all
related  development and operations  have been conducted in material  compliance
with all Laws and in accordance with industry standards.  Except as disclosed in
Schedule  3,  to the  knowledge  of each  Seller,  no such  well is  subject  to
penalties on allowables after the Closing Date because of any  overproduction or
any other violation of Law.

     R.  Status of  Seller.  Neither  Seller is a  non-resident  alien,  foreign
corporation,  foreign  partnership,  foreign  trust or foreign  estate (as those
terms  are  defined  in  the  Internal  Revenue  Code).  Neither  Seller  is  an
"investment company" or a company "controlled" by an "investment company" within
the meaning of the  Investment  Company Act of 1940,  as amended,  nor is either
Seller  otherwise  subject to regulation  under or the restrictions of such act.
Neither  Seller nor the  Guarantor  is a "public  utility  company" or a "public
utility holding  company" or a subsidiary of a "public utility holding  company"
within  the  meaning of the  Public  Utility  Holding  Company  Act of 1935,  as
amended.


                                       11







     S.  Condition of Subject  Interests.  The  machinery,  equipment,  tangible
personal property, fixtures and improvements used in connection with the Subject
Interests or used to process the Subject  Hydrocarbons  or transport them to the
Delivery  Points  (whether owned by either Seller or by a third party  operator)
are adequate  (except for ordinary  repairs,  replacement  and  maintenance)  to
produce the net projected production of PDP Reserves as estimated in the Initial
Reserve Report.

     T. Information True. No information, statement, or certificate with respect
to the  Subject  Interests  furnished  by  either  Seller  or  Guarantor  or any
representative,  employee,  or consultant of either Seller or Guarantor pursuant
hereto or in connection  with the  transactions  contemplated  hereby and by the
Related Agreements, when taken as a whole with all other information provided to
Buyer, contains any untrue statement of a material fact or omits a material fact
necessary to make the statements  contained  therein under the  circumstances in
which they are made not  misleading.  Neither  Seller has  knowledge of any fact
that has not been  disclosed to Buyer which would be likely to adversely  affect
the value of either Production Payment or would be likely to adversely affect in
any material  respect the use or operation of the Subject  Interests or would be
likely to interfere in any material respect with the  transactions  contemplated
by this Agreement or the Related  Agreements.  The engineering  information with
respect to the Subject Interests supplied to Buyer by or on behalf of Sellers is
consistent with the Initial Reserve Report.

     U. Bankruptcy. There are no bankruptcy, reorganization,  assignment for the
benefit  of  creditors  or  arrangement   proceedings  pending  against,   being
contemplated  by, or, to the  knowledge  of either  Seller,  threatened  against
either Seller or Guarantor or any of their respective subsidiaries.

     V.  Dedicated  Contracts and Refund  Obligations.  Other than  contracts on
Schedule  3 of this  Agreement  and other  Permitted  Encumbrances,  no  Subject
Interest  is  dedicated  or  otherwise  subject to any  contract  (other  than a
contract to which Buyer is a party or a  Production  Sale  Contract  approved by
Buyer under a Marketing  Agreement)  for the sale or  transportation  of Subject
Hydrocarbons  that would bind Buyer as the owner of such  Subject  Hydrocarbons.
Neither Seller nor, to the knowledge of either Seller, any of their predecessors
in title, has received prepayments  (including payments for Oil or Gas not taken
pursuant  to  "take  or  pay"  or  similar  contracts)  for any Oil or Gas to be
produced from the Subject  Interests after the Closing Date.  Neither Seller is,
and Buyer as its successor will not be, subject to any kind of refund obligation
(other than  Imbalances as addressed  above) with respect to Oil or Gas produced
from the Subject Interests prior to the Closing Date.

     W. No Material Adverse Change. From December 31, 2004, to the Closing Date,
there has not been any material  adverse  change (other than normal  production,
fluctuations  in the market  prices for Gas and Oil  generally,  or changes that
have  otherwise  been  disclosed  to Buyer in  Schedule 3 hereto) in the Subject
Interests  taken as a whole,  or to the ability of either Seller or Guarantor to
perform their  respective  obligations  under the Related  Agreements taken as a
whole.

     X. Guarantor. Guarantor is rated BBB- by S&P and Baa3 by Moody's.


                                       12







     Y. Insurance. Seller has in full force and effect insurance of the type and
in the amounts set forth in Schedule 2.

SECTION 4.02.    Representations and Warranties of Buyer.

     Buyer  represents  and  warrants to Seller as follows as of the date hereof
and as of the Closing Date:

     A. Organization,  Power and Authorization.  Buyer is a statutory trust duly
organized,  validly existing and in good standing under the laws of the State of
Delaware.  Buyer has all  requisite  power and  authority to execute and deliver
this Agreement and each of the Related  Agreements to which it is a party and to
perform its obligations under this Agreement and each of the Related  Agreements
to which it is a party. The execution, delivery and performance by Buyer of this
Agreement  and  the  Related  Agreements  to  which  it is a  party,  and of the
transactions described herein and therein, have been duly and validly authorized
by all necessary action on the part of Buyer.  Buyer is a "United States person"
within the meaning of Section 7701 of the Internal Revenue Code.

     B. Purchase for Own Account. Buyer is acquiring the Production Payments for
its own account and not with any intention to transfer all or any part of either
Production  Payment to others in violation  of the  Securities  Act of 1933,  as
amended, or any other applicable securities laws.

     C. No Conflicts or Unobtained Consents.  Neither the execution and delivery
of this  Agreement or the Related  Agreements  to which Buyer is a party nor the
consummation  of the  transactions  and  performance of the terms and conditions
contemplated  hereby or thereby by Buyer will (i) conflict with or result in any
breach of any provision of the certificate of incorporation or by-laws (or other
similar governing documents) of Buyer, or (ii) conflict with or be rendered void
or ineffective by or under the terms, conditions, or provisions of any mortgage,
agreement, instrument, or obligation to which Buyer is a party or is subject. No
consent,  approval,  authorization  or permit of, or filing with or notification
to,  any  Person,  that has not  heretofore  been  obtained,  made,  or given is
required for or in connection  with the execution and delivery of this Agreement
or any Related  Agreement by Buyer or for or in connection with the consummation
of the  transactions  and  performance of the terms and conditions  contemplated
hereby or thereby by Buyer

     D.  Enforceability.  This  Agreement  constitutes,  and upon  execution and
delivery  thereof by Buyer each of the  Related  Agreements  to which Buyer is a
party  will  constitute,  the  legal,  valid  and  binding  agreement  of  Buyer
enforceable  against Buyer in accordance with its terms,  subject,  however,  to
bankruptcy,  insolvency,  reorganization,  moratorium  and other laws  affecting
creditors' rights generally and to general principles of equity.

     E. Actions;  Orders.  (i) There are no Actions pending or, to the knowledge
of Buyer,  threatened  which  relate to the  transactions  contemplated  by this
Agreement or the Related Agreements and (ii) there is no judgment or outstanding
order,  injunction,  decree, or award rendered by any Governmental  Authority by
which Buyer or any Affiliate of Buyer is bound that would be likely to adversely

                                       13






affect  the   transactions   contemplated  by  this  Agreement  or  the  Related
Agreements.

     F. Brokerage Fees and Commissions. Neither Buyer nor any Affiliate of Buyer
has incurred any  obligation or entered into any  agreement  for any  investment
banking, brokerage, or finder's fee or commission in respect of the transactions
contemplated by this Agreement or the Related Agreements for which either Seller
shall incur any liability.

                                   ARTICLE V
                          COVENANTS OF SELLER AND BUYER

SECTION 5.01.    Confidentiality and Public Announcements.

     Section 8.10 of each  Conveyance  sets out the  obligations  of the parties
hereto with respect to certain confidential  information,  and each party hereto
shall,  as provided in Section 8.10 of each  Conveyance,  hold in confidence any
confidential  information it has obtained from another party hereto. The parties
acknowledge and agree,  however, that such obligations shall not restrict Buyer,
Seller or Guarantor  from filing this Agreement or the Related  Agreements  with
the Securities  Exchange  Commission or any other Governmental  Authority or any
governmental  department or agency in the United Kingdom or from describing this
Agreement,  the Related Agreements,  or the transactions  contemplated herein or
therein in any press  release  or other  public  statement  or any  earnings  or
analyst  conference  calls.  Section  8.10 of each  Conveyance  and Section 9.15
hereof  shall  not  be  deemed  to  prevent  the  filing  and  recording  of the
Conveyances  or any mortgage,  financing  statement or similar  agreement by any
lender (or trustee or agent on any lender's  behalf) to Buyer in the public deed
records.  Buyer's  lenders and their  Affiliates may also, at their own expense,
publish  customary  "tombstone"  announcements in such publications as they deem
appropriate  following  the  Closing  Date,  and the  parties  hereto  and their
respective  counsel may from time to time refer to such  "tombstones" and repeat
the content thereof to third parties.

SECTION 5.02.    Survival Past Closing.

     All of the representations,  warranties, covenants and agreements contained
in this Agreement  shall survive the Closing and the delivery of the Conveyances
and continue until the termination of each Production Payment as provided in the
applicable Conveyance.

SECTION 5.03.    Reasonable Cooperation.

     From and after the date hereof,  Seller and its Affiliates shall reasonably
cooperate with Buyer and its counsel in connection with the offering and sale of
loans,  certificates of ownership  interest,  or other  instruments  secured by,
payable from or  representing  ownership  interests in the  Production  Payments
(such  instruments  in this  section  called the "VPP  Instruments"),  provided,
however, that such reasonable  cooperation shall be at Buyer's expense and shall
be  limited  to  the  following:  (i)  providing  non-confidential   information
available to Seller that Buyer reasonably deems necessary in connection with the
offering  and sale of VPP  Instruments;  and (ii)  making  available  to Buyer's
lenders, financiers and rating agencies such officers and engineers as Buyer may
reasonably   request  in  order  to  assist  Buyer  in  any  such  financing  or
securitization.

                                       14






SECTION 5.04.    Preference Rights.

     If after the  Closing,  a third party  properly  and  lawfully  exercises a
Preference  Right to purchase either  Production  Payment or any portion thereof
(whether or not such purchase is as a part of a purchase of any Subject Interest
or any portion  thereof),  then Buyer will reconvey such  Production  Payment or
such  portion  thereof  to Seller in order that  Seller  may make the  necessary
conveyance to such third party  purchaser,  and Seller and Buyer shall amend the
applicable  Conveyance  (including  the  Scheduled  Quantities  listed  therein)
accordingly.  The  consideration  payable by such third party purchaser upon the
exercise  of such  preferential  right  shall be paid over by Seller to Buyer in
consideration  of Buyer's  reconveyance.  Since the entire  purchase  price paid
hereunder  by  Buyer  for both  Production  Payments  consists  of both the Cash
Purchase  Price and Buyer's  assumption of certain  hedging  contracts with Swap
Counterparty pursuant to the Novation Agreement, Seller and Buyer shall together
decide  whether  to  request  Swap  Counterparty  to  permit  such  third  party
purchaser,  as part of its purchase price, to assume a proportionate  portion of
the liabilities  under such hedging  contracts or whether to calculate the value
of such liabilities as a component of the cash purchase price to be paid by such
third party  purchaser.  Seller will also  indemnify and hold harmless Buyer for
any losses and  expenses  suffered by Buyer as the result of the exercise of any
such  preferential  right to  purchase,  to the  extent not  compensated  by the
payment to Buyer of the consideration paid by such third party purchaser.

                                   ARTICLE VI
                               CLOSING CONDITIONS

SECTION 6.01.    Seller's Closing Conditions.

     The obligation of Seller to consummate the transactions contemplated hereby
is  subject,  at the option of Seller,  to the  satisfaction  on or prior to the
Closing Date of all of the following conditions:

     A.  Representations,  Warranties,  and Covenants.  The  representations and
warranties of Buyer contained in this Agreement shall have been true and correct
when  made on and as of the  date  of this  Agreement,  and  the  covenants  and
agreements  of Buyer to be performed on or before the Closing Date in accordance
with this Agreement shall have been duly performed.

     B.  Certificate.  Seller shall have received a certificate  dated as of the
Closing Date,  executed by Buyer, to the effect that the conditions set forth in
Subsection A of this Section 6.01 have been satisfied.

     C. Related Agreements.  Buyer shall have executed and delivered each of the
Related Agreements other than the Pioneer Guaranty.

SECTION 6.02.    Buyer's Closing Conditions.

     The obligation of Buyer to consummate the transactions  contemplated hereby
is  subject,  at the  option of Buyer,  to the  satisfaction  on or prior to the
Closing Date of all of the following conditions:

                                       15






     A.  Representations,  Warranties,  and Covenants.  The  representations and
warranties of Seller  contained in this Agreement and of Guarantor  contained in
the Pioneer Guaranty shall have been true and correct when made on and as of the
date of this  Agreement,  and the  covenants  and  agreements  of  Seller  to be
performed on or before the Closing Date in accordance  with this Agreement shall
have been duly performed. There shall have been no fraud committed by the either
Seller  or  Guarantor  in  connection  with  inducing  Buyer to enter  into this
Agreement or the Related Agreements.

     B. Officer's Certificate.  Buyer shall have received a certificate dated as
of the Closing Date,  executed by a duly authorized  officer of each Seller,  to
the  effect  that to such  officer's  knowledge  the  conditions  set  forth  in
Subsection A of this Section 6.02 have been satisfied.

     C. Related  Agreements.  Each Seller shall have  executed and delivered the
Conveyances,  Pioneer  USA shall  have  executed  and  delivered  the  Marketing
Agreements  and the  Novation  Agreement,  and Pioneer  shall have  executed and
delivered to Buyer the Pioneer Guaranty.

     D.  Opinion of  Counsel.  Seller  shall  have  delivered  to Buyer  written
opinions,  dated the  Closing  Date,  of W. Marc  Dingler IV,  Senior  Attorney,
counsel to Seller and Guarantor,  and of Thompson & Knight LLP,  special counsel
to Seller, in forms that are satisfactory to Buyer.

     E.  Production  Sales  Contract.  Buyer shall have  received  copies of the
executed initial  Production  Sales Contract  referred to in Section 2 of either
Marketing Agreement.

     F. Organizational Documents; Incumbency. Buyer shall have received:

        (1) copies  of the articles or  certificates of incorporation of Pioneer
USA and the  partnership  agreement  of Pioneer LP and  Guarantor,  in each case
certified as of a recent date by an appropriate officer of the such Person, each
such   certificate   dated  the  Closing  Date;

        (2) signature and incumbency certificates of the officers of each Seller
and Guarantor executing this Agreement and the Related Agreements;

        (3) resolutions  of the board of  directors or similar governing body of
each Seller and Guarantor approving and authorizing the execution,  delivery and
performance  of  this  Agreement  and the  Related  Agreements,  as  applicable,
certified as of the Closing Date by its  secretary or an assistant  secretary as
being in full force and effect without modification or amendment; and

        (4) a  good  standing   certificate  from  the  applicable  Governmental
Authority of each Seller's  and Guarantor's  jurisdiction of  incorporation, and
each jurisdiction  in which  such Seller owns  S ubject Interests,  each dated a
recent date prior to the Closing Date.

     G.  Insurance.  Buyer  shall have  received  a  certificate  from  Sellers'
insurance broker confirming in reasonable detail that the insurance described in
Schedule 2 is in force.

                                       16






                                  ARTICLE VII
                                     CLOSING

SECTION 7.01.    Closing.

     The Closing  shall be held on the Closing Date at 10:00 a.m.,  Dallas time,
at the offices of Seller's  counsel in Dallas,  Texas,  or at such other time or
place as Seller  and  Buyer may  otherwise  agree.  Each of Seller  and Buyer is
obligated to the other to proceed to Closing,  to satisfy the  conditions to the
other's consummation of the transactions contemplated hereby that are set out in
Article VI hereof,  and to deliver  the  documents  (and  funds,  in the case of
Buyer) that are described in the remainder of this Article VII.

SECTION 7.02.    Seller's Closing Obligations.

     At Closing,  each Seller shall execute and deliver, or cause to be executed
and delivered, to Buyer the following, against delivery of the Purchase Price:

     A. Related Agreements. The Related Agreements;

     B. Officer's  Certificate.  The  certificate of such Seller  referred to in
Section 6.02B;

     C. Legal Opinions. The legal opinions referred to in Section 6.02D;

     D. Sale  Contract.  The Production  Sales  Contract  referred to in Section
6.02E;

     E. Corporate Certificates.  The various certificates referred to in Section
6.02F; and

     F. Insurance Certificate.  The Insurance Certificate referred to in Section
6.02G.

SECTION 7.03.    Buyer's Closing Obligations.

         At Closing, Buyer shall deliver, or cause to be delivered the Purchase
Price in immediately available funds to Seller in the manner provided in Section
3.02, and execute and deliver, or cause to be executed and delivered, to Seller
the following:

     A.  Related  Agreements.  The  Related  Agreements  (other than the Pioneer
Guaranty); and

     B. Certificate. The certificate of Buyer referred to in Section 6.01B.

                                  ARTICLE VIII
                         ASSUMPTION AND INDEMNIFICATION

SECTION 8.01.    Covered Liabilities.

     As used herein, "Covered Liabilities" means:


                                       17






         (1) any and all liabilities, losses, costs, damages, penalties or fines
suffered by any Buyer Party as a result of either Seller's or Guarantor's breach
of any of its respective representations,  warranties,  covenants or obligations
under  this  Agreement  or any of the  Related  Agreements,  including,  without
limitation,  all  of  each  Seller's  obligations  under  Article  VI of  either
Conveyance, and including, without limitation, any Title Failure,

         (2) any and all liabilities, losses, costs, damages, penalties or fines
suffered  by an  Indemnified  Party as a result of (i) any  injury to persons or
property or similar tort arising  from or  involving  activities  on the Subject
Lands or relating to the Subject Hydrocarbons, (ii) any violation on the Subject
Lands (or in  connection  with oil and gas  operations  or ancillary  activities
relating to the Subject  Hydrocarbons) of any Environmental Law or any other Law
or legal  duty  relating  to  public  health  or  safety  or the  production  or
conservation of Hydrocarbons or natural resources,  (iii) the breach of any duty
imposed  under  any such  Law,  or under  any  Lease or  Permitted  Encumbrance,
relating  to  oil  and  gas  operations  and  ancillary  activities   (including
environmental  remediation)  on the  Subject  Lands or  relating  to the Subject
Hydrocarbons, (iv) the delivery to or receipt by Buyer or a designee of Buyer of
any  Hydrocarbons  produced  from  or  attributable  to  the  Subject  Interests
(including any claim relating to the quality or handling thereof) or (v) oil and
gas  operations  and  ancillary  activities on or involving the Subject Lands or
relating to the Subject  Hydrocarbons,  in each case  regardless  of whether the
foregoing  arise under,  out of, or in  connection  with any Action or any claim
therein, any order or decree of any Governmental  Authority, or any arbitrator's
award;

         (3) any and all liabilities, losses, costs, damages, penalties or fines
suffered by any Buyer Party (or any successor owners of the Production  Payment)
as a result of any Action set forth on Schedule 3, and

         (4) all  reasonable costs  and expenses  of any  Indemnified  Party  in
investigating or defending  against any claims for such alleged damages,  costs,
losses,  liabilities,  penalties or fines (including,  without  limitation,  any
reasonable attorneys' fees).

SECTION 8.02.    Indemnification by Seller.

     Buyer will be the purchaser of overriding  royalty interests in the Subject
Interests  and Buyer will not own any  rights to  conduct  or direct  operations
thereon or any  tangible  property  interest  therein or any  equipment  located
thereon,  all such rights,  tangible  property  interests  and  equipment  being
retained by either Seller.  Buyer will not be  responsible  for the operation or
condition of any such property.

     FROM AND AFTER THE CLOSING  DATE,  EACH SELLER SHALL  JOINTLY AND SEVERALLY
INDEMNIFY  AND  HOLD  HARMLESS  EACH  BUYER  PARTY,  THEIR  PRESENT  AND  FORMER
DIRECTORS,  OFFICERS,  EMPLOYEES,  AND AGENTS, AND EACH OF THE HEIRS, EXECUTORS,
SUCCESSORS, AND ASSIGNS OF ANY OF THE FOREGOING (COLLECTIVELY HEREIN REFERRED TO
AS THE "INDEMNIFIED  PARTIES") FROM AND AGAINST ANY AND ALL COVERED LIABILITIES.
THE FOREGOING INDEMNITY SHALL APPLY WHETHER OR NOT THE COVERED LIABILITIES ARISE
OUT OF THE SOLE,  JOINT OR CONCURRENT  NEGLIGENCE,  FAULT OR STRICT LIABILITY OF

                                       18






ANY  INDEMNIFIED  PARTY OR ANY OTHER PERSON  INDEMNIFIED  HEREUNDER AND APPLIES,
WITHOUT LIMITATION,  TO ANY COVERED LIABILITY IMPOSED UPON ANY INDEMNIFIED PARTY
AS A RESULT OF ANY LAW, THEORY OF STRICT  LIABILITY OR OTHERWISE,  EXCEPT TO THE
EXTENT CAUSED BY AN INDEMNIFIED PARTY'S GROSS NEGLIGENCE OR WILLFUL MISCONDUCT.

SECTION 8.03.    Third Party Claims.

     If a claim by a third  party is made  against an  Indemnified  Party and if
such Indemnified Party intends to seek indemnity with respect thereto under this
Article VIII, such  Indemnified  Party shall promptly notify Pioneer USA of such
claim.  Pioneer USA shall have thirty (30) days after  receipt of such notice to
undertake,  conduct, and control, through counsel of its own choosing and at its
own expense,  the settlement or defense thereof, and the Indemnified Party shall
cooperate  with it in  connection  therewith;  provided  that  Pioneer USA shall
permit  the  Indemnified  Party to  participate  in such  settlement  or defense
through  counsel  chosen  by  such  Indemnified  Party  at the  expense  of such
Indemnified  Party and further provided that, to the extent that the Indemnified
Party  reasonably  appears to have  defenses  available to it that are different
from or additional to those  available to either  Seller,  the assertion of such
different  or  additional  defenses by such  counsel  shall be at the expense of
Seller.  So long as Seller,  at its own cost and  expense,  (a) has within  such
thirty (30) days undertaken the defense of, and assumed full  responsibility for
all  Covered  Liabilities  with  respect  to,  such  claim,  (b)  is  reasonably
contesting  such claim in good  faith by  appropriate  proceedings,  and (c) has
taken such action (including the posting of a bond,  deposit, or other security)
as may be  necessary  to  prevent  any  action to  foreclose  a lien  against or
attachment of the property of the  Indemnified  Party for payment of such claim,
the  Indemnified  Party shall not pay or settle any such claim.  Notwithstanding
compliance by Seller with the preceding  sentence,  the Indemnified  Party shall
have the right to pay or settle any such claim - if such claim can be settled by
the  payment of money  damages  only - provided  that,  if Seller is in material
compliance with the preceding sentence at the time of such payment or settlement
by the Indemnified  Party then in such event the  Indemnified  Party shall waive
any right to indemnity therefor by Seller for such claim. If, within thirty (30)
days after the receipt of the Indemnified Party's notice of a claim of indemnity
hereunder,  Pioneer  USA does not  notify  Buyer or the  Indemnified  Party that
Seller  elects,  at its cost and expense,  to undertake the defense  thereof and
assume full  responsibility for all Covered Liabilities with respect thereto, or
gives such notice and thereafter fails to diligently  contest such claim in good
faith by appropriate  proceedings  or to prevent action against the  Indemnified
Party or to foreclose a lien against or  attachment of the  Indemnified  Party's
property as contemplated  above,  the Indemnified  Party shall have the right to
contest,  settle,  or compromise the claim but shall not thereby waive any right
to indemnity therefor pursuant to this Agreement.

                                   ARTICLE IX
                                  MISCELLANEOUS

SECTION 9.01.    Counterparts.

     This Agreement may be executed in one or more  counterparts and by separate
parties on separate  counterparts,  all of which shall be considered one and the

                                       19





same agreement,  and shall become effective when one or more  counterparts  have
been signed by each of the parties and delivered to the other party.

SECTION 9.02.    Governing Law; Consent to Jurisdiction.

     THIS  AGREEMENT  SHALL BE GOVERNED BY AND CONSTRUED IN ACCORDANCE  WITH THE
LAWS OF THE STATE OF TEXAS  WITHOUT  GIVING EFFECT TO ANY CONFLICTS OF LAW RULES
OR PRINCIPLES  THEREOF THAT WOULD DIRECT THE  APPLICATION OF THE LAWS OF ANOTHER
JURISDICTION.

     EACH  OF  SELLER  AND  BUYER  HEREBY  IRREVOCABLY  SUBMITS  ITSELF  TO  THE
NON-EXCLUSIVE  JURISDICTION  OF THE STATE AND FEDERAL  COURTS  SITTING IN DALLAS
COUNTY,  TEXAS AND AGREES AND CONSENTS  THAT SERVICE OF PROCESS MAY BE MADE UPON
IT IN ANY LEGAL PROCEEDING RELATING TO THIS AGREEMENT BY ANY MEANS ALLOWED UNDER
TEXAS OR FEDERAL LAW.  EACH OF SELLER AND BUYER HEREBY  WAIVES AND AGREES NOT TO
ASSERT, BY WAY OF MOTION, AS A DEFENSE OR OTHERWISE, THAT ANY PROCEEDING IN SUCH
VENUES  ARISING OUT OF OR IN ANY WAY RELATED TO THIS  AGREEMENT IS BROUGHT IN AN
INCONVENIENT  FORUM OR THAT THE VENUE  THEREOF  IS  IMPROPER,  AND EACH  FURTHER
CONSENTS TO ANY REQUESTED  TRANSFER OF ANY SUCH PROCEEDING  BROUGHT IN ANY OTHER
VENUE TO A FEDERAL COURT SITTING IN THE NORTHERN DISTRICT OF THE STATE OF TEXAS,
TO THE EXTENT THAT IT HAS SUBJECT MATTER JURISDICTION,  AND OTHERWISE TO A STATE
COURT IN DALLAS COUNTY,  TEXAS. IN FURTHERANCE THEREOF, EACH OF SELLER AND BUYER
HEREBY  ACKNOWLEDGES AND AGREES THAT IT WILL BE NEITHER  INCONVENIENT NOR UNFAIR
TO LITIGATE OR OTHERWISE  RESOLVE ANY  DISPUTES OR CLAIMS IN A COURT  SITTING IN
SUCH COUNTY AND STATE.

SECTION 9.03.    WAIVER OF JURY TRIAL.

     EACH OF THE PARTIES HERETO HEREBY AGREES TO WAIVE ITS RESPECTIVE  RIGHTS TO
A JURY TRIAL OF ANY CLAIM OR CAUSE OF ACTION BASED UPON OR ARISING  HEREUNDER OR
ANY DEALINGS BETWEEN THEM RELATING TO THE SUBJECT MATTER OF THIS AGREEMENT.  THE
SCOPE OF THIS WAIVER IS INTENDED TO BE  ALL-ENCOMPASSING OF ANY AND ALL DISPUTES
THAT MAY BE FILED IN ANY COURT AND THAT  RELATE  TO THE  SUBJECT  MATTER OF THIS
TRANSACTION,  INCLUDING CONTRACT CLAIMS, TORT CLAIMS,  BREACH OF DUTY CLAIMS AND
ALL OTHER COMMON LAW AND STATUTORY CLAIMS.  EACH PARTY HERETO  ACKNOWLEDGES THAT
THIS WAIVER IS A MATERIAL INDUCEMENT TO ENTER INTO A BUSINESS RELATIONSHIP, THAT
EACH HAS ALREADY RELIED ON THIS WAIVER IN ENTERING INTO THIS AGREEMENT, AND THAT
EACH WILL CONTINUE TO RELY ON THIS WAIVER IN ITS RELATED FUTURE  DEALINGS.  EACH
PARTY HERETO FURTHER  WARRANTS AND  REPRESENTS  THAT IT HAS REVIEWED THIS WAIVER

                                       20





WITH ITS LEGAL  COUNSEL AND THAT IT KNOWINGLY  AND  VOLUNTARILY  WAIVES ITS JURY
TRIAL  RIGHTS  FOLLOWING  CONSULTATION  WITH LEGAL  COUNSEL.  THIS WAIVER MAY BE
MODIFIED  ONLY IN  WRITING,  AND  THIS  WAIVER  SHALL  APPLY  TO ANY  SUBSEQUENT
AMENDMENTS,  RENEWALS,  SUPPLEMENTS  OR  MODIFICATIONS  HERETO.  IN THE EVENT OF
LITIGATION,  THIS AGREEMENT MAY BE FILED AS A WRITTEN  CONSENT TO A TRIAL BY THE
COURT.

SECTION 9.04.    Entire Agreement.

         This Agreement and the Related Agreements contain the entire agreement
between the parties with respect to the subject matter hereof and there are no
agreements, understandings, representations, or warranties between the parties
other than those set forth or referred to herein or therein.

SECTION 9.05.    Each Party Pays Own Expenses.

     Except  to  the  extent  provided   otherwise  in  Section  2.3  of  either
Conveyance,  Buyer shall be responsible  for all income and other Taxes incurred
by or imposed on Buyer as the owner of the  Production  Payments and the Subject
Hydrocarbons allocable thereto. Seller shall be responsible for certain Taxes as
provided in Section 2.3 of each Conveyance,  and Seller shall be responsible for
all income  taxes and other Taxes  incurred by or imposed on Seller with respect
to the sale of the Production  Payments or as the owner of the residual interest
in the  Subject  Interests  and the  Subject  Hydrocarbons.  All other costs and
expenses incurred by each party hereto in connection with all things required to
be done by it hereunder,  including  attorneys' fees,  accountant fees,  reserve
engineering fees, recording fees, and the expense of title examination, shall be
borne by the party incurring the same.

SECTION 9.06.    Notices.

     All  notices  and other  communications  hereunder  shall be in writing and
shall be deemed  sufficiently  given for all purposes hereof if (a) delivered in
person,  by courier or by  registered  or  certified  United  States Mail to the
Person to be notified,  with receipt obtained, or (b) sent by telecopy,  telefax
or other  facsimile or  electronic  transmission,  with  "answer  back" or other
"evidence  of  receipt"  obtained,  in each case to the  appropriate  address or
number as set  forth in  Section  8.2 of the Oil  Conveyance  (or at such  other
address or number for a party as shall be specified by like notice). Each notice
shall be deemed  effective on receipt by the  addressee as  aforesaid;  provided
that,  notice  received by telecopy,  telefax or other  facsimile or  electronic
transmission  after 5:00 p.m. at the  location of the  addressee  of such notice
shall be deemed  received on the first  business day  following the date of such
electronic receipt.

SECTION 9.07.    Successors and Assigns.

     A. General  Provisions.  This Agreement  shall be binding upon and inure to
the  benefit  of  the  parties  hereto  and  their   respective   heirs,   legal
representatives, successors and assigns; provided, however, that no party to any
Production  Payment  Document  may assign or transfer its rights or duties under
such Production  Payment Document unless the assignee is similarly assigned (and

                                       21






accepts in a writing  delivered  to the other  parties  thereto)  the rights and
duties of such assignor party under all other Production Payment Documents.

     B. Additional Restrictions on Buyer. Buyer may not grant any mortgage, lien
or security  interest  burdening  either  Production  Payment or any  Production
Payment  Document  or any  interest  therein  unless (a) the  recipient  of such
mortgage,  lien or security interest is obligated to Seller to join in or ratify
any releases and  acknowledgments  of termination that Buyer is required to give
under the  Production  Payment  Documents and (b) the documents  governing  such
mortgage,   lien  or  security   interest   provide  that,  in  connection  with
foreclosure,  the  successor  to Buyer must  accepts in a writing  delivered  to
Seller  the  rights  and  duties of Buyer  under all of the  Production  Payment
Documents.  Buyer may not assign or transfer  either  Production  Payment or any
Production Payment Document or any interest therein (including any transfer upon
foreclosure of a mortgage,  lien or security interest) to any Person that is, at
the time of such assignment or transfer, an Unqualified Foreign Assignee.

     C. Additional  Restrictions on Seller.  Seller shall not assign the Subject
Interests or any part thereof  (except as allowed under  Sections 6.2 and 6.5 of
the  Conveyances),  unless (i) Seller's entire  remaining  interests  (including
working interests and net revenue interests) in all the Subject Interests (after
creation of the Production Payment) are assigned to a single assignee,  (ii) the
assignee has sufficient experience and capability in the oil business to perform
the  obligations  of Seller  hereunder and under the Related  Agreements,  (iii)
Seller furnishes to Buyer a written  instrument,  in recordable form and for the
benefit  of  Buyer  and  the  other  beneficiaries  under  Section  7.1 of  each
Conveyance,  in which the assignee  expressly  assumes the obligations of Seller
under the  Production  Payment  Documents,  and (iv) either (a) Pioneer  remains
obligated under the Pioneer Guaranty for such assignee's  obligations  under the
Production  Payment  Documents  or (b) the  assignee  (or any  Affiliate  of the
assignee who provides Buyer with a guaranty,  in substantially  the same form as
the Pioneer Guaranty, of the assignee's obligations under the Production Payment
Documents) is rated  Approved  Investment  Grade.  Buyer will  release,  without
representation,  warranty or recourse,  the current Seller from its  obligations
hereunder and under the other  Production  Payment  Documents,  and will release
Pioneer (or any allowed  successor  guarantor) from the Pioneer Guaranty (or any
successor  guaranty),  concurrently  with  (i)  any  assignment  that is made in
compliance with the  requirements  of clauses (i), (ii),  (iii) and (iv) of this
Subsection  C,  including  the  delivery to Buyer of the new  guaranty,  if any,
required by the preceding sub-clause C(iii)(b);  provided,  that notwithstanding
the foregoing, any obligations which any Person may have to indemnify, reimburse
or  compensate  Buyer or to make  payments  to Buyer on account of  hydrocarbons
produced before such time shall survive such release unless expressly assumed by
a Person rated Approved Investment Grade.

     D.  Approved  Investment  Grade.  A Person shall be deemed rated  "Approved
Investment  Grade"  in  2005,  2006 or 2007 if the  long-term  senior  unsecured
obligations  of such Person are rated at or above  "BBB+" by S&P and at or above
"Baa1" by  Moody's,  and a Person  shall be deemed  rated  "Approved  Investment
Grade" after 2007 if the long-term senior  unsecured  obligations of such Person
are  rated at or above  "BBB"  flat  (no plus or  minus)  by S&P and at or above
"Baa2" by Moody's.

     E. Exception for Assignments to Seller's  Affiliates.  Notwithstanding  the
foregoing  Subsection C, Seller may assign some or all of the Subject  Interests
to one or more  Affiliates,  whether by conveyance,  merger,  consolidation,  or

                                       22






otherwise,  provided  Pioneer  (or  any  allowed  successor  guarantor)  remains
obligated  under the Pioneer  Guaranty (or any successor  guaranty) for Seller's
(and any such Affiliate's)  obligations under the Production  Payment Documents,
and provided  further that if such Subject  Interests  are assigned to more than
one Affiliate,  the obligations of such  Affiliates  shall be joint and several.
Seller (or its  successor by merger or  consolidation)  will remain liable under
the Production  Payment  Documents after any such  assignment,  provided that if
Seller assigns the Subject Interests of record to three or fewer such Affiliates
and  furnishes to Buyer a written  instrument,  in  recordable  form and for the
benefit  of  Buyer  and  the  other  beneficiaries  under  Section  7.1 of  each
Conveyance, in which such assignee or assignees expressly assume the obligations
of Seller under the Production Payment  Documents,  then Buyer will upon request
release Seller from its obligations under the Production Payment Documents.

SECTION 9.08.    Headings.

     The  headings  to  Articles,  Sections,  and  other  subdivisions  of  this
Agreement are inserted for convenience of reference only and will not affect the
meaning or interpretation of this Agreement.

SECTION 9.09.    Amendments and Waivers.

     This  Agreement  may  not be  waived,  modified  or  amended  except  by an
instrument  or   instruments  in  writing  signed  by  the  party  against  whom
enforcement of any such  modification or amendment is sought.  The waiver by any
party hereto of a breach of any term or provision of this Agreement shall not be
construed as a waiver of any subsequent breach.

SECTION 9.10.    Schedules and Exhibits.

     All Schedules  and Exhibits  hereto which are referred to herein are hereby
made a part hereof and incorporated herein by such reference.

SECTION 9.11.    Interpretation.

     In construing this Agreement:

     A.  Examples.  Examples  shall not be construed  to limit,  expressly or by
implication, the matter they illustrate;

     B. Including.  The word "includes" and its derivatives means "includes, but
is not limited to" and corresponding derivative expressions;

     C.  Location  of  Definitions.  A  defined  term  has its  defined  meaning
throughout  this  Agreement and each Schedule to this  Agreement,  regardless of
whether it appears before or after the place where it is defined;

     D.  Controlling  Provisions.  Each Schedule to this  Agreement is a part of
this Agreement,  but if there is any conflict or inconsistency  between the main

                                       23






body of this Agreement and any Schedule, the provisions of the main body of this
Agreement shall prevail; and

     E. Neutral  Interpretation.  This  Agreement is the result of  arm's-length
negotiations  from equal  bargaining  positions by all parties.  It is expressly
agreed that this  Agreement  shall not be  construed  against any party,  and no
consideration  shall be given or  presumption  made on the basis of who  drafted
this  Agreement or any particular  provision  hereof or who supplied the form of
Agreement.

SECTION 9.12.    Agreement for the Parties' Benefit Only.

     Nothing in this Agreement is intended to confer upon any Person, other than
the parties and their respective  successors and permitted assigns,  any rights,
benefits,  remedies  or  obligations  hereunder;  and no Person,  other than the
parties and their respective  successors and permitted  assigns,  is entitled to
rely on any representation,  warranty,  covenant, or agreement contained herein;
provided,  however, that Buyer and its successors and permitted assigns shall be
entitled to enforce the terms of Article VIII for the benefit of any Persons who
are Indemnified  Parties.  Any claim for  indemnification  under Article VIII on
behalf of an  Indemnified  Party  other  than  Buyer (or  Buyer's  successor  or
permitted  assign) must be made and  administered  by Buyer or its  successor or
permitted assign.

SECTION 9.13.    Severability.

     If any term or other  provision of this Agreement is invalid,  illegal,  or
incapable  of being  enforced  by any rule of Law or  public  policy,  all other
conditions and provisions of this 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 adverse  manner to any party.  Upon
such  determination  that any term or other  provision is invalid,  illegal,  or
incapable of being enforced, the parties hereto shall negotiate in good faith to
modify  this  Agreement  so as to effect the  original  intent of the parties as
closely as possible  in an  acceptable  manner to the end that the  transactions
contemplated hereby are fulfilled to the extent possible.

SECTION 9.14.    No Retained Liens.

     No lien or encumbrance of whatsoever nature,  express or implied,  shall be
retained by or created in favor of either Seller in or against either Production
Payment as security  for payment or  performance  of the  Purchase  Price or any
other obligations of Buyer; and each Seller hereby expressly waives and releases
any such express or implied liens and encumbrances.

SECTION 9.15.    Limitations on Damages.

         NEITHER PARTY HERETO SHALL BE RESPONSIBLE TO THE OTHER PARTY OR TO ANY
PERMITTED BENEFICIARY HEREOF FOR CONSEQUENTIAL DAMAGES OR PUNITIVE OR EXEMPLARY
DAMAGES.

                                       24






SECTION 9.16.    Tax Treatment.

     Although each Production  Payment is a real property  interest for purposes
of state law, the parties agree to treat each  Production  Payment as a mortgage
loan for  federal  income tax  purposes.  For  avoidance  of doubt,  the parties
acknowledge  that  Sellers  (and not  Buyer)  are  entitled  to all tax  credits
(including  credits under Section 29 of the Internal Revenue Code)  attributable
to either Production Payment and the production attributable thereto.

SECTION 9.17.    LIMITATION OF OWNER TRUSTEE LIABILITY.

     IT IS EXPRESSLY UNDERSTOOD AND AGREED BY THE PARTIES THAT (A) THIS DOCUMENT
IS EXECUTED AND DELIVERED BY  WILMINGTON  TRUST  COMPANY,  NOT  INDIVIDUALLY  OR
PERSONALLY,  BUT  SOLELY AS OWNER  TRUSTEE,  IN THE  EXERCISE  OF THE POWERS AND
AUTHORITY  CONFERRED  AND VESTED IN IT,  PURSUANT TO THE TRUST  AGREEMENT  UNDER
WHICH  BUYER HAS BEEN  CREATED AS A DELAWARE  STATUTORY  TRUST,  (B) EACH OF THE
REPRESENTATIONS, UNDERTAKINGS AND AGREEMENTS HEREIN MADE ON THE PART OF BUYER IS
MADE AND INTENDED NOT AS PERSONAL  REPRESENTATIONS,  UNDERTAKINGS AND AGREEMENTS
BY WILMINGTON TRUST COMPANY BUT IS MADE AND INTENDED FOR THE PURPOSE FOR BINDING
ONLY SUCH TRUST, (C) NOTHING HEREIN CONTAINED SHALL BE CONSTRUED AS CREATING ANY
LIABILITY ON WILMINGTON  TRUST COMPANY,  INDIVIDUALLY OR PERSONALLY,  TO PERFORM
ANY COVENANT EITHER EXPRESSED OR IMPLIED CONTAINED  HEREIN,  ALL SUCH LIABILITY,
IF ANY, BEING EXPRESSLY  WAIVED BY THE PARTIES HERETO AND BY ANY PERSON CLAIMING
BY, THROUGH OR UNDER THE PARTIES HERETO,  AND (D) UNDER NO  CIRCUMSTANCES  SHALL
WILMINGTON   TRUST  COMPANY  BE  PERSONALLY   LIABLE  FOR  THE  PAYMENT  OF  ANY
INDEBTEDNESS OR EXPENSES OF SUCH TRUST OR BE LIABLE FOR THE BREACH OR FAILURE OF
ANY OBLIGATION, REPRESENTATION,  WARRANTY OR COVENANT MADE OR UNDERTAKEN BY SUCH
TRUST UNDER THIS AGREEMENT OR ANY OTHER RELATED DOCUMENTS.

              [The remainder of this page intentionally left blank]



                                       25







     IN WITNESS WHEREOF,  this Agreement has been signed by or on behalf of each
of the parties as of the day first above written.

                               BUYER:

                               WOLFCAMP OIL AND GAS TRUST

                               By: WILMINGTON TRUST COMPANY,
                                   not in its individual capacity but solely as
                                   Owner Trustee


                                   By:    /s/ Rosemary Kennard
                                        ---------------------------------------
                                   Name:  Rosemary Kennard
                                          Authorized Signatory


                                      S-1







                                   SELLER:

                                   PIONEER NATURAL RESOURCES USA, INC.


                                   By:   /s/ Richard P. Dealy
                                       ----------------------------------------
                                        Richard P. Dealy
                                        Executive Vice President and Chief
                                        Financial Officer

                                   PIONEER NATURAL RESOURCES PROPERTIES LP

                                   By: Westpan Properties, Inc.,
                                       its general partner


                                       By:  /s/ Richard P. Dealy
                                           ------------------------------------
                                            Richard P. Dealy
                                            Executive Vice President and Chief
                                            Financial Officer


                                      S-2