1 EXECUTION COPY AMENDED AND RESTATED CREDIT AGREEMENT AMENDED AND RESTATED CREDIT AGREEMENT dated as of March 31, 1997 among VASTAR RESOURCES, INC. (with its successors, the "Borrower"), the BANKS listed on the signature pages hereof (with their successors, the "Banks"), MORGAN GUARANTY TRUST COMPANY OF NEW YORK, as Agent for the Banks (with its successors, the "Agent"), and the Co-Agents listed on the signature pages hereof (with their successors, the "Co- Agents"). W I T N E S S E T H : WHEREAS, the parties hereto have heretofore entered into a 5-Year Revolving Credit Agreement dated as of May 5, 1995 (as amended by Amendment No. 1 thereto and as in effect from time to time prior to the Effective Date (as defined below), as amended and restated hereby and as amended from time to time thereafter, the "Credit Agreement"); and WHEREAS, the parties hereto desire to amend the Credit Agreement as set forth herein and to restate the Credit Agreement in its entirety to read as set forth in the Credit Agreement with the amendments specified below; NOW, THEREFORE, the parties hereto agree as follows: SECTION 1. Definitions; References. Unless otherwise specifically defined herein, each term used herein which is defined in the Credit Agreement as in effect immediately prior to the Effective Date shall have the meaning assigned to such term in the Credit Agreement as so in effect. Each reference to "hereof", "hereunder", "herein" and "hereby" and each other similar reference and each reference to "this Agreement" and each other similar reference contained in the Credit Agreement shall from and after the date hereof refer to the Credit Agreement as amended hereby. SECTION 2. Amendment to Section 1.01 of the Agreement. Section 1.01 of the Credit Agreement is amended by replacing the definition of Commitment Termination Date to read in full as follows: "Commitment Termination Date" means March 31, 2002, or if such day is not a Euro-Dollar Business Day, the next preceding Euro-Dollar Business Day. 2 SECTION 3. Representations and Warranties. The Borrower hereby represents and warrants that as of the date hereof and after giving effect hereto: (a) no Default under the Credit Agreement has occurred and is continuing; and (b) each representation and warranty of the Borrower set forth in the Credit Agreement is true and correct as though made on and as of this date. SECTION 4. Governing Law. This Agreement shall be governed by and construed in accordance with the laws of the State of New York. SECTION 5. Counterparts; Conditions to Effectiveness. This Agreement may be signed in any number of counterparts, each of which shall be an original, with the same effect as if the signatures thereto and hereto were upon the same instrument. This Agreement shall become effective (and the Credit Agreement shall be amended and restated in the form of the Credit Agreement immediately before giving effect hereto and with the amendments referred to herein) as of the date hereof (the "Effective Date") when the Agent shall have received a duly executed counterparts hereof signed by the Borrower and all of the Banks (or, in the case of any party as to which an executed counterpart shall not have been received, the Agent shall have received telegraphic, telex or other written confirmation from such party of execution of a counterpart hereof by such party). 2 3 IN WITNESS WHEREOF, the parties hereto have caused this Amended and Restated Credit Agreement to be duly executed by their respective authorized officers as of the day and year first above written. VASTAR RESOURCES, INC. By /s/ Daniel D. Hawk ---------------------------------- Title: Treasurer 3 4 MORGAN GUARANTY TRUST COMPANY OF NEW YORK, as Bank and Agent By /s/ John Kowalczuk ---------------------------------- Title: Vice President NATIONSBANK OF TEXAS, N.A., as Bank and Co-Agent By /s/ Patrick M. Delaney ---------------------------------- Title: Senior Vice President TEXAS COMMERCE BANK NATIONAL ASSOCIATION, as Bank and Co-Agent By /s/ James C. Nicholas ---------------------------------- Title: Managing Director UNION BANK OF SWITZERLAND, as Bank and Co-Agent By /s/ Cynthia A. P. Deere ---------------------------------- Title: Vice President By /s/ Kelly Boots ---------------------------------- Title: Assistant Vice President 4 5 BANK OF MONTREAL By /s/ Bryan R. Gallow ---------------------------------- Title: Managing Director THE BANK OF NEW YORK By /s/ John W. Hall ---------------------------------- Title: Vice President THE BANK OF NOVA SCOTIA By /s/ F. C. H. Ashby ---------------------------------- Title: Senior Manager Loan Operations CITIBANK, N.A. By /s/ Arezoo Jafari ---------------------------------- Title: Assistant Vice President CREDIT LYONNAIS CAYMAN ISLAND BRANCH By /s/ Pascal Poupelle ---------------------------------- Title: Authorized Signature 5 6 THE FUJI BANK, LIMITED By /s/ Nobuhiro Umemura ---------------------------------- Title: Joint General Manager THE INDUSTRIAL BANK OF JAPAN, LIMITED By /s/ Kensaku Iwata ---------------------------------- Title: Vice President, Houston Office LTCB TRUST COMPANY By /s/ John J. Sullivan ---------------------------------- Title: Executive Vice President MELLON BANK, N.A. By /s/ A. J. Sabatelle ---------------------------------- Title: First Vice President SOCIETE GENERALE By /s/ Richard Ebert ---------------------------------- Title: Vice President 6 7 WACHOVIA BANK OF GEORGIA, N.A. By /s/ Joel K. Wood ---------------------------------- Title: Vice President BANK OF AMERICA NATIONAL TRUST AND SAVINGS ASSOCIATION By /s/ Vanessa Sheh Meyer ---------------------------------- Title: Vice President THE DAI-ICHI KANGYO BANK, LTD. By /s/ Masatsugu Morishita ---------------------------------- Title: Sr. Vice President & Joint General Manager PNC BANK, NATIONAL ASSOCIATION By /s/ John R. Way ---------------------------------- Title: Commercial Banking Officer ROYAL BANK OF CANADA By /s/ Linda M. Stephens ---------------------------------- Title: Manager 7 8 THE SUMITOMO BANK, LIMITED By /s/ Toshihiro Kubota ---------------------------------- Title: Joint General Manager BARCLAYS BANK PLC By /s/ George McKean ---------------------------------- Title: Director KREDIETBANK, N.V. By /s/ Robert Snauffer ---------------------------------- Title: Vice President By /s/ Tod R. Angus ---------------------------------- Title: Vice President NORTHERN TRUST COMPANY By /s/ Martin G. Alston ---------------------------------- Title: Vice President THE SANWA BANK, LIMITED By /s/ Gill Realon ---------------------------------- Title: Vice President 8 9 TORONTO DOMINION (TEXAS), INC. By /s/ Neva Nesbitt ---------------------------------- Title: Vice President 9