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                                                                EXHIBIT 10.13.1



                         FIRST AMENDMENT TO AMENDED AND
                           RESTATED CREDIT AGREEMENT

                                  BY AND AMONG
                             TITAN RESOURCES, L.P.,
                                  as Company,



                           THE CHASE MANHATTAN BANK,
                            as Administrative Agent,



                  FIRST UNION NATIONAL BANK OF NORTH CAROLINA,
                             as Documentation Agent



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



                                      and



                          THE LENDERS SIGNATORY HERETO

                                  May 12, 1997




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                         FIRST AMENDMENT TO AMENDED AND
                           RESTATED CREDIT AGREEMENT

This FIRST AMENDMENT TO AMENDED AND RESTATED CREDIT AGREEMENT (this "First
Amendment") dated effective as of the 12th day of May, 1997 (the "Effective
Date"), is by and among TITAN RESOURCES, L.P., a Texas limited partnership (the
("Company"); THE CHASE MANHATTAN BANK, individually, as the Issuing Bank and as
Administrative Agent (in such capacity, the "Administrative Agent"); FIRST
UNION NATIONAL BANK OF NORTH CAROLINA, individually and as Documentation Agent
(in such capacity, the "Documentation Agent"); MORGAN GUARANTY TRUST COMPANY
OF NEW YORK, individually and as Syndication Agent (in such capacity, the
"Syndication Agent"); and each of the lenders that is a signatory hereto or
which becomes a signatory hereto and to the Credit Agreement (hereinafter
defined) as provided in Section 8.07 of the Credit Agreement (individually,
together with its successors and assigns, "Lender" and collectively,
"Lenders").

                                  WITNESSETH:

WHEREAS, the Company, the Administrative Agent, the Documentation Agent, the
Syndication Agent and Lenders are parties to that certain Amended and Restated
Credit Agreement dated as of October 31, 1996 (the "Credit Agreement"),
pursuant to which Lenders agreed to make loans to and extensions of credit on
behalf of the Company; and

WHEREAS, the Company, the Administrative Agent, the Documentation Agent, the
Syndication Agent and Lenders desire to amend the Credit Agreement in the
particulars hereinafter provided;

NOW, THEREFORE, in consideration of the premises and the mutual covenants
herein contained, the parties hereto agree as follows:

                             ARTICLE I. DEFINITIONS


Section 1.01 Terms Defined Above. As used in this First Amendment, each of the
terms "Administrative Agent," "Company," "Credit Agreement," "Documentation
Agent," "First Amendment," "Lender," "Lenders" and "Syndication Agent" shall
have the meaning assigned to such term hereinabove.

Section 1.02 Terms Defined in Credit Agreement. Each term defined in the Credit
Agreement and used herein without definition shall have the meaning assigned to
such term in the Credit Agreement, unless expressly provided to the contrary.

Section 1.03  Other Definitional Provisions.

(a) The words "hereby," "herein," "hereinafter", "hereof," "hereto" and
"hereunder" when used in this First Amendment shall refer to this First
Amendment as a whole and not to any particular Article, Section, subsection or
provision of this First Amendment.

(b) Section, subsection and Exhibit references herein are to such Sections,
subsections and Exhibits to this First Amendment unless otherwise specified.

                   ARTICLE II. AMENDMENTS TO CREDIT AGREEMENT

The Company, the Administrative Agent, the Documentation Agent, the Syndication
Agent and Lenders agree that the Credit Agreement is hereby amended, effective
as of the Effective Date, in the following particulars.

Section 2.01 Amendments and Supplements to Definitions.


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(a) The term "Agreement," as defined in the Credit Agreement, is hereby amended
to mean the Credit Agreement, as amended and supplemented by this First
Amendment and as the same may from time to time be further amended or
supplemented.

(b) The term "Guarantors," as defined in the Credit Agreement, is hereby
amended in its entirety to read as follows:

         "Guarantors" means (a) the Parent, ((b)) the General Partner, (C)
         Titan Resources Holdings, Inc., a Nevada corporation, and (d) those
         Subsidiaries of the Company designated as Guarantors on Exhibit B and
         any other Subsidiary of the Company, designated as a Guarantor by (i)
         the Company with the approval of the Administrative Agent, or (ii) the
         Majority Lenders, in each case pursuant to Section 5.01(j).

Section 2.02 Amendment to Section 5.03(d) - Distribution, Etc. Section 5.03(d)
of the Credit Agreement is hereby amended in its entirety to read as follows:

         "(d) Distribution, etc. Make any distribution of profits or purchase,
         redeem or otherwise acquire for value any of the partnership interests
         in the Company now or hereafter outstanding, return any capital to its
         Partners, or make any distribution of its assets to its Partners as
         such; provided, however, so long as no Default or Event of Default has
         occurred and is continuing hereunder or would occur as a consequence
         thereof, the Company may make (i) distributions to its Partners for
         the payment of cash taxes due and payable by the Partners as a result
         of their partnership interests in the Company, (ii) distributions to
         the Parent which will be used by the Parent from time to time to
         purchase up to and including $25,000,000 in the aggregate of its
         issued and outstanding common stock; provided, however, no such
         distribution shall be made unless twenty-five percent (25%) of the
         Maximum Available Amount shall remain available under this Agreement
         after giving effect to the latest borrowings hereunder made in
         connection with the acquisition of the Parent's common stock, and
         (iii) other distributions to its Partners not to exceed $2,500,000 in
         the aggregate in any calendar year, less the aggregate principal
         amount of Indebtedness permitted by Section 5.03(a)(v) which is
         incurred and outstanding in the same calendar year."

Section 2.03 Amendment to Section 5 03(j) - Proceeds of Loan. Section 5.03(j)
is hereby amended by deleting clause (iii) from the first sentence thereof and
substituting in its place a new clause (iii) and a new clause (iv) which shall
read in their entirety, as follows:

         "(iii) for general corporate purposes (not including dividends or
         distributions to its Partners) and (iv) to pay dividends or make
         distributions to its Parent for the purpose of enabling its Parent to
         repurchase from time to time its issued and outstanding common stock;
         provided, however, no borrowings may be made on the Loan in connection
         with any repurchase of the Parent's common stock, unless twenty-five
         percent (25%) of the Maximum Available Amount shall remain available
         under this Agreement after giving effect to the latest borrowings
         hereunder made in connection with the acquisition of the Parent's
         common stock."



                           ARTICLE III. MISCELLANEOUS

Section 3.01 Adoption. Ratification and Confirmation of Credit Agreement. Each
of the Company, the Administrative Agent, the Documentation Agent, the
Syndication Agent and Lenders does hereby adopt, ratify and confirm the Credit
Agreement, as amended hereby, and acknowledges and agrees that the Credit
Agreement, as amended hereby, is and remains in full force and effect.

Section 3.02 Successors and Assigns. This First Amendment shall be binding upon
and inure to the benefit of the parties hereto and their respective successors
and assigns permitted pursuant to the Credit Agreement.

Section 3.03 Counterparts. This First Amendment may be executed by one or more
of the parties hereto in any number of separate counterparts, and all of such
counterparts taken together shall be deemed to constitute one and the same
instrument and shall be enforceable as of the Effective Date upon the execution
of one or more counterparts hereof by the Company, the Administrative Agent,
the Documentation Agent, the Syndication Agent 




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and Lenders. In this regard, each of the parties hereto acknowledges that a
counterpart of this First Amendment containing a set of counterpart execution
pages reflecting the execution of each party hereto shall be sufficient to
reflect the execution of this First Amendment by each necessary party hereto
and shall constitute one instrument.

Section 3.04 Number and Gender. Whenever the context requires, reference herein
made to the single number shall be understood to include the plural; and
likewise, the plural shall be understood to include the singular. Words
denoting sex shall be construed to include the masculine, feminine and neuter,
when such construction is appropriate; and specific enumeration shall not
exclude the general but shall be construed as cumulative. Definitions of terms
defined in the singular or plural shall be equally applicable to the plural or
singular, as the case may be, unless otherwise indicated.

Section 3.05 Entire Agreement. This First Amendment constitutes the entire
agreement among the parties hereto with respect to the subject hereof. All
prior understandings, statements and agreements, whether written or oral,
relating to the subject hereof are superseded by this First Amendment.

Section 3.06 Invalidity. In the event that any one or more of the provisions
contained in this First Amendment shall for any reason be held invalid, illegal
or unenforceable in any respect, such invalidity, illegality or
unenforceability shall not affect any other provision of this First Amendment.

Section 3.07 Titles of Articles. Sections and Subsections. All titles or
headings to Articles, Sections, subsections or other divisions of this First
Amendment or the exhibits hereto, if any, are only for the convenience of the
parties and shall not be construed to have any effect or meaning with respect
to the other content of such Articles, Sections, subsections, other divisions
or exhibits, such other content being controlling as the agreement among the
parties hereto.

Section 3.08 Governing Law. This First Amendment shall be deemed to be a
contract made under and shall be governed by and construed in accordance with
the internal laws of the State of New York.

THIS FIRST AMENDMENT, THE CREDIT AGREEMENT, AS SUPPLEMENTED AND AMENDED HEREBY,
THE NOTES, AND THE OTHER SECURITY INSTRUMENTS REPRESENT THE FINAL AGREEMENT
BETWEEN THE PARTIES AND MAY NOT BE CONTRADICTED BY EVIDENCE OF PRIOR,
CONTEMPORANEOUS, OR SUBSEQUENT ORAL AGREEMENTS OF THE PARTIES.



IN WITNESS WHEREOF, the parties hereto have caused this First Amendment to be
duly executed and delivered by their proper and duly authorized officers as of
the Effective Date.



 BORROWER:                     TITAN RESOURCES, L.P., a Texas limited
                               partnership

                               By: Titan Resources I, Inc., its General Partner

                                        By: /s/ Jack Hightower
                                           -----------------------------------
                                        Name:   Jack Hightower
                                        Title:  President

 AGENT AND LENDERS:            THE CHASE MANHATTAN BANK, Individually
                               as Issuing Bank and as Administrative Agent

                                        By: /s/ Mary Jo Woodford
                                           -----------------------------------
                                        Name:   Mary Jo Woodford

                                        Title:  Vice President


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                               FIRST UNION NATIONAL BANK OF NORTH
                               CAROLINA, Individually and as Documentation
                               Agent

                                        By:/s/ Michael J. Kolosowsky
                                           -----------------------------------
                                        Name:   Michael J. Kolosowsky

                                        Title:  Vice President


                               MORGAN GUARANTY TRUST COMPANY OF
                               NEW YORK, Individually and as Syndication Agent


                                        By:/s/ John Kowalczuk
                                           -----------------------------------
                                        Name:   John Kowalczuk

                                        Title:  Vice President



                               CREDIT LYONNAIS NEW YORK BRANCH

                                        By:/s/ Pascal Poupelle
                                           -----------------------------------
                                        Name:   Pascal Poupelle

                                        Title:  Executive Vice President


                               BANK ONE, TEXAS, N.A..


                                        By:/s/ Wm. Mark Cramer
                                           -----------------------------------
                                        Name:   Wm. Mark Cramer

                                        Title:  Vice President



                               BANQUE PARIBAS

                                        By:/s/ Brian Malone
                                           -----------------------------------
                                        Name:   Brian Malone

                                        Title:  Vice President


                                        By:/s/ Marian Livingston
                                           -----------------------------------
                                        Name:   Marian Livingston

                                        Title:  Vice President


                               UNION BANK OF CALIFORNIA, N.A..


                                        By:/s/ Katie Murray
                                           -----------------------------------
                                        Name:   Katie Murray

                                        Title:  Vice President



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                                        By:/s/ Tony R. Werber
                                           -----------------------------------
                                        Name:   Tony R. Werber

                                        Title:  Vice President








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