1

                                                                   EXHIBIT 10.30

                            [PRIMARY CREDIT FACILITY]

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

                               FIRST AMENDMENT TO
                 AMENDED AND RESTATED CREDIT FACILITY AGREEMENT

                                  by and among

                       PIONEER NATURAL RESOURCES COMPANY,
                                  as Borrower,

                                       and

                               NATIONSBANK, N.A.,
                            as Administrative Agent,

                                       and

                                   CIBC INC.,
                             as Documentation Agent,

                                       and

                   MORGAN GUARANTY TRUST COMPANY OF NEW YORK,
                             as Documentation Agent,

                                       and

                            THE CHASE MANHATTAN BANK,
                              as Syndication Agent,

                         THE CO-AGENTS SIGNATORY HERETO,

                                       and

                       THE OTHER LENDERS SIGNATORY HERETO


                            Dated as of June 29, 1998

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


   2


                               FIRST AMENDMENT TO
                 AMENDED AND RESTATED CREDIT FACILITY AGREEMENT

         THIS FIRST AMENDMENT TO AMENDED AND RESTATED CREDIT FACILITY AGREEMENT
(herein called this "Amendment"), is made as of June 29, 1998, by and among
PIONEER NATURAL RESOURCES COMPANY, a Delaware corporation (the "Borrower"),
NATIONSBANK, N.A., as successor-by-merger to NationsBank of Texas, N.A., as
Administrative Agent and Collateral Agent, CIBC INC., as Documentation Agent,
MORGAN GUARANTY TRUST COMPANY OF NEW YORK, as Documentation Agent, THE CHASE
MANHATTAN BANK, as Syndication Agent, the "Co-Agents" party to the Credit
Agreement (as herein defined), and the other Lenders from time to time parties
to the Credit Agreement.

                              W I T N E S S E T H:

         WHEREAS, the Borrower, the Lenders, the Managing Agents, the Collateral
Agent and the Co-Agents have heretofore entered into a certain Amended and
Restated Credit Facility Agreement - Primary Credit Facility, dated as of 
December 18, 1997 (herein the "Credit Agreement"); and

         WHEREAS, the Borrower, the Lenders, the Managing Agents, the Collateral
Agent and the Co-Agents now intend to amend the Credit Agreement in certain
respects; and

         NOW, THEREFORE, in consideration of the premises and the mutual
agreements herein contained , each of the Borrower, the Lenders, the Managing
Agents, the Collateral Agent and the Co-Agents hereby agree as follows:

         SECTION 1. Defined Terms. All capitalized terms used but not otherwise
defined herein shall have the meanings given in the Credit Agreement.

         SECTION 2.  Amendments to Credit Agreement

         a.            The Credit Agreement is hereby amended by modifying each
                  reference therein to "NationsBank of Texas, N.A." to read
                  "NationsBank, N.A., successor-by-merger to NationsBank of
                  Texas, N.A."

         b.            The definitions of "Amendment Fee Rate" and "Eurodollar
                  Margin" in Section 1.1 of the Credit Agreement are hereby
                  amended and restated to read in their entirety as follows:

         "        "Amendment Fee Rate" means 15.0 basis points."

         "        "Eurodollar Margin" means, on any date, with respect to each
         Eurodollar Portion of a Revolving Loan, the sum of (i) the applicable
         Commitment Utilization Margin plus (ii) the number of basis points per
         annum set forth below based on the Applicable Rating Level on such
         date:


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=========================================================
        Applicable
       Rating Level
- ---------------------------------------------------------
                                           
         Level I                        18.0 b.p.
- ---------------------------------------------------------
         Level II                       20.0 b.p.
- ---------------------------------------------------------
         Level III                      23.0 b.p.
- ---------------------------------------------------------
         Level IV                       36.0 b.p.
- ---------------------------------------------------------
         Level V                        45.0 b.p.
=========================================================


         Changes in the Eurodollar Margin will occur automatically without prior
         notice. Administrative Agent will give notice promptly to Borrower and
         the Lenders of changes in the Eurodollar Margin."

         c.            Section 1.1 of the Credit Agreement is hereby amended by
                  inserting the following definitions of "Commitment
                  Utilization", "Commitment Utilization Level", "Commitment
                  Utilization Margin", "Year 2000 Compliant" and "Year 2000
                  Problem" in appropriate alphabetical order:

         "        "Commitment Utilization" means, for any period, the ratio of 
         (i) the aggregate amount of then outstanding Loans plus then existing 
         LC Obligations to (ii) the current Facility Amount."

         "        "Commitment Utilization Level" means the level set forth below
         that corresponds to the lowest of the ratings issued from time to time 
         by Moody's and S&P, as applicable, for Borrower's senior unsecured
         long-term debt:



========================================================================
                                Moody's                 S&P
- ------------------------------------------------------------------------
                                                        
Level A                      Baa3 or better        BBB- or better
- ------------------------------------------------------------------------
Level B                      Less than Baa3        Less than BBB-
========================================================================


         For example, if the Moody's rating is Ba1 and the S&P rating is BBB,
         Level B shall apply. For purposes of the foregoing, (i) if ratings for
         Borrower's senior unsecured long-term debt shall not be available from
         S&P or Moody's, Level B shall be deemed applicable; and (ii) if any of
         the Rating Agencies shall change its ratings nomenclature prior to the
         date all Obligations have been paid and the Commitments canceled,
         Borrower and the Lenders shall negotiate in good faith to amend the
         references to specific ratings in this definition to reflect such
         change, and pending such amendment, if an appropriate Commitment
         Utilization Level is otherwise not determinable based upon the
         foregoing grid, the last Commitment Utilization Level in effect at the
         time of such change shall continue to apply."



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         " "Commitment Utilization Margin" means, on any date, the number of
         basis points per annum set forth below based on the Commitment
         Utilization Level on such date:



================================================================================
                               Commitment Utilization Margin
- --------------------------------------------------------------------------------
                                   Commitment                 Commitment
     Commitment                  Utilization is              Utilization is
  Utilization Level            "< or equal to .50"               ">.50"
- --------------------------------------------------------------------------------
                                                            
       Level A                        0 b.p.                    5.0 b.p.
- --------------------------------------------------------------------------------
       Level B                        0 b.p.                   10.0 b.p.
================================================================================


         ; provided, however, for the purpose of determining the Commitment
         Utilization Margin for all periods ending prior to or on June 30, 1999,
         the Commitment Utilization of Borrower shall be deemed to be greater
         than ".50". Changes in the Commitment Utilization Margin will occur
         automatically without prior notice."

         "        "Year 2000 Compliant" has the meaning given it in Section
         4.1(s)."

         "        "Year 2000 Problem" has the meaning given it in Section 
         4.1(s)."

         d.            Section 4.1 of the Credit Agreement is hereby amended by
                  inserting the following Section 4.1(s) after Section 4.1(r):

         "(s)     Year 2000 Compliance. Borrower has (i) initiated a review
                  and assessment of all areas within its and each of its
                  Subsidiaries' business and operations (including those
                  affected by suppliers and vendors) that could be adversely
                  affected by the Year 2000 Problem (as herein defined), (ii)
                  developed a plan and time line for addressing the Year 2000
                  Problem on a timely basis, and (iii) to date, implemented that
                  plan in accordance with that timetable. Borrower reasonably
                  believes that all computer applications (including those of
                  its suppliers and vendors) that are material to its or any of
                  its Subsidiaries' business and operations will be Year 2000
                  Compliant, except to the extent that a failure to do so could
                  not reasonably be expected to have Material Adverse Effect. As
                  used herein, the term "Year 2000 Problem" means the risk that
                  computer applications used by the Borrower or any of its
                  Subsidiaries (or its suppliers and vendors) may be unable to
                  recognize and perform properly date- sensitive functions
                  involving certain dates prior to and any date after December
                  31, 1999. As used herein, the term "Year 2000 Compliant" means
                  that all computer applications will on a timely basis be able
                  to perform properly date-sensitive functions for all dates
                  before and after January 1, 2000."

         e.            Section 5.1 of the Credit Agreement is hereby amended by
                  inserting the following Section 5.1(m) after Section 5.1(l):


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         "(m)     Year 2000 Compliance. Borrower will promptly notify
                  Administrative Agent in the event Borrower discovers or
                  determines that any computer application (including those of
                  its suppliers and vendors) that is material to its or any of
                  its Subsidiaries' business and operations will not be Year
                  2000 Compliant on a timely basis, except to the extent that
                  such failure could not reasonably be expected to have a
                  Material Adverse Effect."

         f.            Section 5.3(a) of the Credit Agreement is hereby amended 
                  and restated to read in its entirety as follows:

                  "(a) EBITDAX to Consolidated Interest Expense Ratio. The ratio
         of Borrower's "EBITDAX" to "Consolidated Interest Expense" for the last
         four rolling Fiscal Quarters (i) ending June 30, 1998 and September 30,
         1998, will not be less than 2.50 to 1.0, (ii) ending December 31, 1998,
         will not be less than 2.75 to 1.0, (iii) ending March 31, 1999, will
         not be less than 3.00 to 1.0, (iv) ending June 30, 1999, will not be
         less than 3.25 to 1.0, and (v) ending after June 30, 1999, will not be
         less than 3.75 to 1.0; provided, however, that for the periods for
         calculation ending on or before December 31, 1998, each reference to
         "for the last four rolling Fiscal Quarters" shall be deemed to be a
         reference to the period from April 1, 1998 through the date of such
         calculation. As used in this paragraph, the term "Consolidated Interest
         Expense" means for any period, total interest expense, whether paid or
         accrued, of Borrower and its Subsidiaries on a Consolidated basis,
         including, without limitation, all commissions, discounts and other
         fees and charges owed with respect to Letters of Credit. As used in
         this paragraph, the term "EBITDAX" means for any period the sum of the
         amounts for such period of Consolidated net income, Consolidated
         Interest Expense, depreciation expense, depletion expense, amortization
         expense, federal and state income taxes, exploration and abandonment
         expense and other non-cash charges and expenses, all as determined on a
         Consolidated basis for Borrower and its Subsidiaries."

         g.            Section 5.3(b) of the Credit Agreement is hereby amended 
                  and restated to read in its entirety as follows:

                  "(b) Consolidated Total Funded Debt to Total Capitalization.
         Borrower's Consolidated Total Funded Debt to Total Capitalization will
         not (i) as of the last day of the Fiscal Quarters ending June 30, 1998
         and September 30, 1998, be greater than 62.5%, and (ii) as of the last
         day of any Fiscal Quarter ending after September 30, 1998, be greater
         than 60%."

         h.            The fourth sentence of Section 8.17 of the Credit 
                  Agreement is hereby amended and restated to read in its 
                  entirety as follows:

         "FOR THE PURPOSE OF ANY ACTION OR PROCEEDING INSTITUTED IN THE FEDERAL
         OR STATE COURTS OF TEXAS, EACH RESTRICTED SUBSIDIARY OF THE BORROWER
         HEREBY IRREVOCABLY DESIGNATES BORROWER WITH OFFICES ON THE DATE HEREOF
         AT 1400 WILLIAMS 



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         SQUARE WEST, 5205 NORTH O'CONNOR BOULEVARD, IRVING, TEXAS 75039 TO
         RECEIVE FOR AND ON BEHALF OF SUCH RESTRICTED SUBSIDIARY, SERVICES OF
         PROCESS IN TEXAS."

         i.            The Credit Agreement is hereby amended by replacing 
                  Exhibit J to the Credit Agreement with Exhibit J to this 
                  Amendment.

         j.            Schedule 3 attached to the Credit Agreement is hereby 
                  amended by deleting therefrom the reference to "Pioneer 
                  Natural Resources (GPC) Inc., a Delaware corporation".

         SECTION 3. Representations and Warranties. To confirm each Lender's
understanding concerning Borrower and its businesses, properties and
obligations, and to induce the Managing Agents, the Collateral Agent, the
Co-Agents and each Lender to enter into this Amendment, the Borrower hereby
reaffirms to the Managing Agents, the Collateral Agent, the Co-Agents and each
Lender that, as of the date hereof, its representations and warranties contained
in Section 4.1 of the Credit Agreement (as amended by this Amendment) and in the
other Loan Documents to which it is a party (except to the extent such
representations and warranties relate solely to an earlier date) are true and
correct and additionally represents and warrants as follows:

A.       The execution and delivery of this Amendment and the performance by the
         Borrower and the Restricted Subsidiaries of their respective
         obligations under this Amendment, the Credit Agreement and the other
         Loan Documents, as amended hereby, are within the Borrower's or such
         Restricted Subsidiaries' corporate or partnership powers, have been
         duly authorized by all necessary corporate or partnership action, have
         received all necessary governmental approval (if any shall be
         required), and do not and will not contravene or conflict with any
         provision of law or of the Borrower's or such Restricted Subsidiaries'
         charter or bylaws or partnership agreement or of any contractual
         restriction, law or governmental regulation or court decree or order
         binding on or affecting the Borrower or such Restricted Subsidiary.

B.       This Amendment and the Credit Agreement as amended hereby are, and the
         other Loan Documents when duly executed and delivered will be, legal,
         valid and binding obligations of the Borrower and each Restricted
         Subsidiary which is a party hereto or thereto, enforceable in
         accordance with their terms except as such enforcement may be limited
         by bankruptcy, insolvency or similar laws of general application
         relating to the enforcement of creditors' rights generally and by
         general principles of equity.

         SECTION 4. Conditions to Effectiveness. The effectiveness of this
Amendment is conditioned upon receipt by the Administrative Agent of all the
following documents and items, each in form and substance reasonably
satisfactory to the Administrative Agent:

A.       this Amendment executed by the Borrower and the Required Lenders.

B.       Borrower will pay, or cause the payment, to Administrative Agent for
         the account of each Lender a non-refundable amendment fee payable to
         each Lender determined by applying the


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         Amendment Fee Rate to such Lender's Percentage Share of the Facility
         Amount as of the date of this Amendment.

C.       Such other documents or items that the Administrative Agent may
         reasonably request.

         SECTION 5. Reaffirmation of Credit Agreement. This Amendment
constitutes a "Loan Document" as defined in the Credit Agreement and shall be
deemed to be an amendment to the Credit Agreement, and the Credit Agreement, as
amended hereby, is hereby ratified, approved and confirmed in each and every
respect. All references to the Credit Agreement or the Credit Facility Agreement
in any other document, instrument, agreement or writing shall hereafter be
deemed to refer to the Credit Agreement as amended hereby.

         SECTION 6. Parties in Interest. All grants, covenants and agreements
contained in this Amendment shall bind and inure to the benefit of the parties
thereto and their respective successors and assigns; provided, however, that no
Restricted Subsidiary may assign or transfer any of its rights or delegate any
of its duties or obligations under this Amendment or any Loan Document without
the prior written consent of all Lenders.

         SECTION 7. Counterparts. This Amendment may be separately executed in
any number of counterparts and by different parties hereto in separate
counterparts, each of which when so executed shall be deemed to constitute one
and the same Amendment.

         SECTION 8. GOVERNING LAW. THIS AMENDMENT AND THE OTHER LOAN DOCUMENTS
SHALL BE DEEMED CONTRACTS AND INSTRUMENTS MADE UNDER THE LAWS OF THE STATE OF
TEXAS AND SHALL BE CONSTRUED AND ENFORCED IN ACCORDANCE WITH AND GOVERNED BY THE
LAWS OF THE STATE OF TEXAS AND THE LAWS OF THE UNITED STATES OF AMERICA, WITHOUT
REGARD TO PRINCIPLES OF CONFLICTS OF LAW. CHAPTER 15 OF TEXAS REVISED CIVIL
STATUTES ANNOTATED ARTICLE 5069 (WHICH REGULATES CERTAIN REVOLVING CREDIT LOAN
ACCOUNTS AND REVOLVING TRI-PARTY ACCOUNTS) DOES NOT APPLY TO THIS AMENDMENT OR
TO THE NOTES.

         SECTION 9. Severability. If any term or provision of this Amendment or
of any Loan Document shall be determined to be illegal or unenforceable in any
jurisdiction, such term or provision shall, as to such jurisdiction, be illegal
or unenforceable, without affecting the remaining terms or provisions in that
jurisdiction or the legality or enforceability of such terms or provisions in
any other jurisdiction.

         SECTION 10.  WAIVER OF JURY TRIAL, PUNITIVE DAMAGES.  EACH OF THE
BORROWER, AGENTS AND LENDERS HEREBY (I) IRREVOCABLY WAIVES, TO THE MAXIMUM
EXTENT NOT PROHIBITED BY LAW, ANY RIGHT IT MAY HAVE TO A TRIAL BY JURY IN
RESPECT OF ANY LITIGATION, DIRECTLY OR INDIRECTLY, AT ANY TIME ARISING OUT OF,
UNDER OR IN CONNECTION WITH THE LOAN DOCUMENTS OR ANY TRANSACTION CONTEMPLATED
THEREBY OR ASSOCIATED THEREWITH, BEFORE OR AFTER MATURITY; (II) IRREVOCABLY
WAIVES, TO THE MAXIMUM EXTENT NOT PROHIBITED BY LAW, ANY RIGHT IT MAY HAVE TO
CLAIM OR RECOVER IN ANY 



                                       6
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SUCH LITIGATION ANY EXEMPLARY, PUNITIVE OR CONSEQUENTIAL DAMAGES; (III)
CERTIFIES THAT NO PARTY HERETO NOR ANY REPRESENTATIVE OR AGENT OR COUNSEL FOR
ANY PARTY HERETO HAS REPRESENTED, EXPRESSLY OR OTHERWISE, OR IMPLIED THAT SUCH
PARTY WOULD NOT, IN THE EVENT OF LITIGATION, SEEK TO ENFORCE THE FOREGOING
WAIVERS; AND (IV) ACKNOWLEDGES THAT IT HAS BEEN INDUCED TO ENTER INTO THIS
AMENDMENT, THE OTHER LOAN DOCUMENTS AND THE TRANSACTIONS CONTEMPLATED HEREBY AND
THEREBY BY, AMONG OTHER THINGS, THE MUTUAL WAIVERS AND CERTIFICATIONS CONTAINED
IN THIS SECTION.

         SECTION 11. FORUM SELECTION AND CONSENT TO JURISDICTION. ANY LITIGATION
BASED HEREON, OR ARISING OUT OF, UNDER, OR IN CONNECTION WITH, THIS AMENDMENT OR
ANY OTHER LOAN DOCUMENT, OR ANY COURSE OF CONDUCT, COURSE OF DEALING, STATEMENTS
(WHETHER VERBAL OR WRITTEN) OR ACTIONS OF THE AGENTS, THE LENDERS OR THE
BORROWER SHALL BE BROUGHT AND MAINTAINED EXCLUSIVELY IN THE COURTS OF THE STATE
OF TEXAS OR IN THE UNITED STATES DISTRICT COURT FOR THE NORTHERN DISTRICT OF
TEXAS; PROVIDED, HOWEVER, THAT ANY SUIT SEEKING ENFORCEMENT AGAINST ANY
COLLATERAL OR OTHER PROPERTY MAY BE BROUGHT, AT THE COLLATERAL AGENT'S OPTION,
IN THE COURTS OF ANY JURISDICTION WHERE SUCH COLLATERAL OR OTHER PROPERTY MAY BE
FOUND. BORROWER HEREBY EXPRESSLY AND IRREVOCABLY SUBMITS TO THE JURISDICTION OF
THE COURTS OF THE STATE OF TEXAS AND THE UNITED STATES DISTRICT COURT FOR THE
NORTHERN DISTRICT OF TEXAS FOR THE PURPOSE OF ANY SUCH LITIGATION AS SET FORTH
ABOVE AND IRREVOCABLY AGREES TO BE BOUND BY ANY JUDGMENT RENDERED THEREBY IN
CONNECTION WITH SUCH LITIGATION. BORROWER FURTHER IRREVOCABLY CONSENTS TO THE
SERVICE OF PROCESS BY REGISTERED MAIL, POSTAGE PREPAID, OR BY PERSONAL SERVICE
WITHIN OR WITHOUT THE STATE OF TEXAS. FOR THE PURPOSE OF ANY ACTION OR
PROCEEDING INSTITUTED IN THE FEDERAL OR STATE COURTS OF TEXAS, EACH RESTRICTED
SUBSIDIARY OF THE BORROWER HEREBY IRREVOCABLY DESIGNATES BORROWER WITH OFFICES
ON THE DATE HEREOF AT 1400 WILLIAMS SQUARE WEST, 5205 NORTH O'CONNOR BOULEVARD,
IRVING, TEXAS 75039 TO RECEIVE FOR AND ON BEHALF OF SUCH RESTRICTED SUBSIDIARY,
SERVICE OF PROCESS IN TEXAS. BORROWER HEREBY EXPRESSLY AND IRREVOCABLY WAIVES,
TO THE FULLEST EXTENT PERMITTED BY LAW, ANY OBJECTION WHICH IT MAY HAVE OR
HEREAFTER MAY HAVE TO THE LAYING OF VENUE OF ANY SUCH LITIGATION BROUGHT IN ANY
SUCH COURT REFERRED TO ABOVE AND ANY CLAIM THAT ANY SUCH LITIGATION HAS BEEN
BROUGHT IN AN INCONVENIENT FORUM. TO THE EXTENT THAT THE BORROWER HAS OR
HEREAFTER MAY ACQUIRE ANY IMMUNITY FROM JURISDICTION OF ANY COURT OR FROM ANY
LEGAL PROCESS (WHETHER THROUGH SERVICE OR NOTICE, ATTACHMENT PRIOR TO JUDGMENT,
ATTACHMENT IN AID OF EXECUTION OR OTHERWISE) WITH RESPECT TO ITSELF OR ITS
PROPERTY, BORROWER HEREBY IRREVOCABLY WAIVES SUCH IMMUNITY IN RESPECT OF ITS
OBLIGATIONS UNDER THIS AMENDMENT AND THE OTHER LOAN DOCUMENTS.



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         SECTION 12. Effectiveness. This Amendment shall become effective as of
June 29, 1998, when counterparts hereof executed on behalf of the Borrower and
each Lender (or notice thereof satisfactory to the Agent) shall have been
received by the Administrative Agent, and all conditions set forth in Section 4
hereof have been fulfilled.

         SECTION 13.  Entire Agreement.  THIS WRITTEN AMENDMENT AND THE OTHER
LOAN DOCUMENTS REPRESENT THE FINAL AGREEMENT BETWEEN THE PARTIES AND MAY NOT BE 
CONTRADICTED BY EVIDENCE OF PRIOR, CONTEMPORANEOUS, OR SUBSEQUENT ORAL 
AGREEMENTS OF THE PARTIES.

           THERE ARE NO UNWRITTEN ORAL AGREEMENTS BETWEEN THE PARTIES.

                    [SIGNATURES BEGIN ON THE FOLLOWING PAGE]



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         IN WITNESS WHEREOF, this Amendment is executed as of the date first
written above.

                                     BORROWER:

                                     PIONEER NATURAL RESOURCES COMPANY

                                     By: /s/ Garrett Smith
                                        ----------------------------------------
                                     Name:   M. Garrett Smith
                                     Title:  Executive Vice President and Chief
                                             Financial Officer

                                     LENDERS:

                                     NATIONSBANK, N.A., 
                                     successor-by-merger to NationsBank of
                                     Texas, N.A., individually and as 
                                     Administrative Agent and as Collateral 
                                     Agent

                                     By: /s/ Frank K. Stowers
                                         ---------------------------------------
                                     Name:   Frank K. Stowers
                                     Title:  Vice President

                                     CIBC INC.,
                                     individually and as Documentation Agent

                                     By: /s/ M.A.G. Corkum
                                        ----------------------------------------
                                     Name:   Michael A.G. Corkum
                                     Title:  Authorized Signatory

                                     MORGAN GUARANTY TRUST COMPANY OF NEW YORK, 
                                     individually and as Documentation Agent

                                     By: /s/ John Kowalczuk
                                        ----------------------------------------
                                     Name:   John Kowalczuk
                                     Title:  Vice President



                                       S-1

   11


                                     THE CHASE MANHATTAN BANK,
                                     individually and as Syndication Agent

                                     By: /s/ Lawrence Palumbo, Jr.
                                        ----------------------------------------
                                     Name:   Lawrence Palumbo, Jr.
                                     Title:  Vice President

                                     BANK OF AMERICA NATIONAL TRUST AND SAVINGS
                                     ASSOCIATION, individually and as Co-Agent

                                     By: /s/ Ronald E. McKaig
                                        ----------------------------------------
                                     Name:   Ronald E. McKaig
                                     Title:  Vice President

                                     THE BANK OF NEW YORK, 
                                     individually and as Co-Agent

                                     By: /s/ Raymond J. Palmer
                                        ----------------------------------------
                                     Name:   Raymond J. Palmer
                                     Title:  Vice President

                                     THE BANK OF NOVA SCOTIA,
                                     individually and as Co-Agent

                                     By: /s/ F.C.H. Ashby
                                        ----------------------------------------
                                     Name:   F.C.H. Ashby
                                     Title:  Senior Manager, Loan Operations

                                     ROYAL BANK OF CANADA, 
                                     individually and as Co-Agent

                                     By: /s/ Linda M. Stephens
                                        ----------------------------------------
                                     Name:   Linda M. Stephens
                                     Title:  Senior Manager

                                     UNION BANK OF CALIFORNIA, N.A., 
                                     individually and as Co-Agent

                                     By: /s/ Gary Shekerjian
                                        ----------------------------------------
                                     Name:   Gary Shekerjian
                                     Title:  Assistant Vice President



                                       S-2

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                                     WELLS FARGO BANK, N.A.,
                                     individually and as Co-Agent

                                     By: /s/ Lester J.N. Keliher
                                        ----------------------------------------
                                     Name:   Lester J.N. Keliher
                                     Title:  Vice President

                                     THE FUJI BANK, LIMITED-HOUSTON AGENCY, 
                                     individually and as Co-Agent

                                     By: /s/ David Kelley
                                        ----------------------------------------
                                     Name:   David Kelley
                                     Title:  Sr. Vice President

                                     DEN NORSKE BANK ASA, 
                                     individually and as Lead Manager

                                     By: /s/ J. Morten Kreutz
                                        ----------------------------------------
                                     Name:   J. Morten Kreutz
                                     Title:  Vice President

                                     By: /s/ Charles E. Hall
                                        ----------------------------------------
                                     Name:   Charles E. Hall
                                     Title:  Senior Vice President

                                     BANQUE PARIBAS,
                                     individually and as Lead Manager

                                     By: /s/ A. David Dodd
                                        ----------------------------------------
                                     Name:   A. David Dodd
                                     Title:  Vice President

                                     By: /s/ Marian Livingston
                                        ----------------------------------------
                                     Name:   Marian Livingston
                                     Title:  Vice President

                                     FIRST UNION NATIONAL BANK,
                                     individually and as Lead Manager

                                     By: /s/ Robert R. Wetteroff
                                        ----------------------------------------
                                     Name:   Robert R. Wetteroff
                                     Title:  Senior Vice President


                                       S-3

   13



                                     BANKERS TRUST COMPANY, 
                                     as a Lender

                                     By: /s/ Marcus Tarkington
                                        ----------------------------------------
                                     Name:   Marcus Tarkington
                                     Title:  Vice President

                                     CREDIT AGRICOLE INDOSUEZ, 
                                     as a Lender

                                     By:/s/ Dean Balice
                                        ----------------------------------------
                                     Name:  Dean Balice
                                     Title: Senior Vice President, Branch
                                            Manager

                                     By: /s/ W. Leroy Startz
                                        ----------------------------------------
                                     Name:   W. Leroy Startz
                                     Title:  First Vice President

                                     NATEXIS BANQUE,
                                     as a Lender BFCE

                                     By: /s/ Mark A. Harrington
                                        ----------------------------------------
                                     Name:   Mark A. Harrington
                                     Title:  Vice President and Regional
                                             Manager

                                     By: /s/ N. Eric Ditges
                                        ----------------------------------------
                                     Name:   N. Eric Ditges
                                     Title:  Assistant Vice President

                                     TORONTO DOMINION (TEXAS), INC., 
                                     as a Lender

                                     By: /s/ Debbie A. Greene
                                        ----------------------------------------
                                     Name:   Debbie A. Greene
                                     Title:  Vice President

                                     THE TOYO TRUST & BANKING CO., LTD.,
                                     as a Lender

                                     By: /s/ T. Mikumo
                                        ----------------------------------------
                                     Name:   T. Mikumo
                                     Title:  Vice President


                                       S-4

   14



                                     WACHOVIA BANK, N.A.,
                                     as a Lender

                                     By:
                                        ----------------------------------------
                                     Name:
                                     Title:

                                     THE DAI-ICHI KANGYO BANK, LTD., NEW YORK
                                     BRANCH, as a Lender

                                     By:
                                        ----------------------------------------
                                     Name:
                                     Title:

                                     THE SANWA BANK, LIMITED, 
                                     as a Lender

                                     By:
                                        ----------------------------------------
                                     Name:
                                     Title:

                                     KBC BANK N.V.,
                                     as a Lender

                                     By:
                                        ----------------------------------------
                                     Name:
                                     Title:

                                     By:
                                        ----------------------------------------
                                     Name:
                                     Title:


                                       S-5

   15



                                    Exhibit J

                    Form of Designated Officer's Certificate

         Reference is made to (i) the Primary Credit Facility pursuant to that
certain Amended and Restated Credit Facility Agreement dated as of December 18,
1997, as amended, by and among Borrower, NationsBank, N.A., as Administrative
Agent, CIBC Inc., as Documentation Agent, Morgan Guaranty Trust Company of New
York, as Documentation Agent, The Chase Manhattan Bank, as Syndication Agent,
the Co-Agents party thereto, and the Lenders from time to time parties thereto
(the "Primary Credit Agreement") and (ii) the 364 Day Credit Facility pursuant
to that certain Amended and Restated Credit Facility Agreement dated as of
December 18, 1997, as amended, by and among Borrower, NationsBank, N.A., as
Administrative Agent, CIBC Inc., as Documentation Agent, Morgan Guaranty Trust
Company of New York, as Documentation Agent, The Chase Manhattan Bank, as
Syndication Agent, the Co-Agents party thereto, and the Lenders from time to
time parties thereto (the "364 Day Credit Agreement" and, together with the
Primary Credit Facility, the "Credit Agreements"). Terms which are defined in
the Credit Agreements and which are used but not defined herein are used herein
with the meanings given them in the Credit Agreements.

         This Certificate is furnished pursuant to Section 5.1(b)(2) of the
Credit Agreements. Together herewith the Borrower is furnishing to Managing
Agents, the Co-Agents and each Lender the Borrower's [Financial Statements] (the
"Financial Statements") as of _____________ (the "Reporting Date"). The Borrower
hereby represents, warrants, and acknowledges to Agents and each Lender that:

         (a)      the Designated Officer of the Borrower signing this instrument
                  is a duly elected, qualified and acting officer of the
                  Borrower;

         (b)      the Financial Statements are accurate and complete and satisfy
                  the requirements of the Credit Agreements;

         (c)      attached as Schedule I hereto is a schedule of calculations
                  showing compliance (or noncompliance, as the case may be) as
                  of the Reporting Date with the requirements of Section 5.3 of
                  the Credit Agreements; and

         (d)      on the Reporting Date, the Borrower was, and on the date
                  hereof the Borrower is, in full compliance with the disclosure
                  requirements of Section 5.1(d) of the Credit Agreements, and
                  no Default otherwise existed on the Reporting Date or
                  otherwise exists on the date of this Certificate [except for
                  Default(s) under Section(s) _______________  of the Credit
                  Agreements, which [is/are] more fully described on a schedule
                  attached hereto].



                               Exhibit J - Page 1

   16



         The Designated Officer of the Borrower signing this instrument hereby
certifies that he has reviewed the Loan Documents and the Financial Statements
and has otherwise undertaken such inquiry as is in his opinion necessary to
enable him to express an informed opinion with respect to the above
representations, warranties and acknowledgments of the Borrower and, to the best
of his knowledge, such representations, warranties, and acknowledgments are
true, correct and complete.

                                     PIONEER NATURAL RESOURCES COMPANY

                                     By:
                                        ----------------------------------------
                                     Name:
                                     Title:
                                     
                                     Date:
                                          --------------------------------------


                               Exhibit J - Page 2

   17


                                   Schedule I

================================================================================
COMPLIANCE WITH FINANCIAL COVENANTS AS OF _____________ . ($ in 000's)
================================================================================

A.     EBITDAX TO CONSOLIDATED INTEREST EXPENSE RATIO
                                                                      ========

            Minimum ratio allowed          :1      
                                        ========

B.     CONSOLIDATED TOTAL FUNDED DEBT TO TOTAL
       CAPITALIZATION
                                                                      ========

            Maximum ratio allowed           %     
                                        ========

================================================================================
COMPUTATION OF FINANCIAL REQUIREMENTS AND RATIOS AS OF ______________
================================================================================

A.     EBITDAX TO CONSOLIDATED INTEREST EXPENSE RATIO
       (Section 5.3(a)) ($ in 000's)


                                                                                     
          (i)  EBITDAX (as defined in Section 5.3(a))

               For the period ended __________ , the sum of the amounts for such
               period of Consolidated net income, Consolidated Interest Expense,
               depreciation expense, depletion expense, amortization expense,
               federal and state income taxes, exploration and abandonment
               expense and other non-cash charges and expenses, all as
               determined on a Consolidated basis for Borrower and its
               Consolidated Subsidiaries;                                            $
                                                                                      ---------

          (ii) CONSOLIDATED INTEREST EXPENSE (as defined in Section 5.3(a))

               For the period ended ___________, total interest expense, whether 
               paid or accrued, of Borrower and its Consolidated Subsidiaries on 
               a Consolidated basis, including, without limitation, all
               commissions, discounts and other fees and charges owed with
               respect to Letters of Credit.                                         $ 
                                                                                      ---------

               CONSOLIDATED INTEREST EXPENSE                                         $              
                                                                                      =========

               EBITDAX TO CONSOLIDATED INTEREST EXPENSE RATIO ((i)(ii))              $              
                                                                                      =========
 
               Minimum ratio allowed         :1     
                                          ==========



                               Exhibit J - Page 3


   18


B.       CONSOLIDATED TOTAL FUNDED DEBT TO TOTAL
         CAPITALIZATION (Section 5.3(b)) ($ in 000's)


                                                                                  
            (i) CONSOLIDATED TOTAL FUNDED DEBT (as defined in Section 1.1)

                (a) All indebtedness of Borrower and its Consolidated
                    Subsidiaries for borrowed money                                  $
                                                                                      ---------

                (b) Plus indebtedness of Borrower and its Consolidated
                    Subsidiaries constituting an obligation to pay the deferred
                    purchase price of property or services (other than customary
                    payment terms taken in the ordinary course of the business)      $
                                                                                      ---------

                (c) Plus indebtedness of Borrower and its Consolidated
                    Subsidiaries evidenced by a bond, debenture, note or similar
                    instrument                                                       $
                                                                                      ---------

                (d) Plus principal obligations under leases capitalized in
                    accordance with GAAP under which either Borrower or any of
                    its Consolidated Subsidiaries is the lessee                      $
                                                                                      ---------

                (e) Plus indebtedness or obligations of the type described in
                    clauses (a), (b), (c) or (d) of the definition of Debt,
                    which are secured by a Lien on any property owned by
                    Borrower or any of its Consolidated Subsidiaries, whether or
                    not such indebtedness or obligations have been assumed by
                    Borrower or any of its Consolidated Subsidiaries (limited
                    however to the lesser of (1) the amount of its liability or
                    (2) the value of such property) (excluding Debt of the type
                    referred to in clause (e) of the definition of "Debt")           $
                                                                                      ---------

                (f) Plus the undischarged balance of any production payment
                    created by Borrower or any of its Consolidated Subsidiaries
                    or for the creation of which Borrower or its Consolidated
                    Subsidiaries directly or indirectly received payment.            $
                                                                                      ---------

                CONSOLIDATED TOTAL FUNDED DEBT                                       $             
                                                                                      =========



                               Exhibit J - Page 4


   19
 


                                                                              
           (ii) TOTAL CAPITALIZATION (as defined in Section 1.1)

                (a) Consolidated Total Funded Debt of the Borrower and its
                    Consolidated Subsidiaries (See B(i) above)                       $
                                                                                      ---------

                (b) Plus Consolidated shareholders' equity of the Borrower and
                    its Consolidated Subsidiaries                                    $
                                                                                      ---------

                TOTAL CAPITALIZATION                                                 $             
                                                                                      =========

CONSOLIDATED TOTAL FUNDED DEBT TO TOTAL
CAPITALIZATION((i)/(ii))                                                                       %
                                                                                      =========

                Maximum ratio allowed                                                          %     
                                                                                      =========




                               Exhibit J - Page 5