<PAGE>

                                                                   EXHIBIT 10.19

                                                                  EXECUTION COPY

                           AMENDMENT NO. 2, dated as of December 5, 2002 (this
                  "Amendment No. 2" or this "Amendment"), in respect of the
                  LONG-TERM REVOLVING CREDIT AGREEMENT, dated as of February 25,
                  1998, as amended and restated as of December 7, 2001 (the
                  "Credit Agreement"), among BURLINGTON RESOURCES INC., a
                  Delaware corporation (the "Borrower"), the financial
                  institutions (the "Lenders") listed on the signature pages
                  thereof, JPMorgan Chase Bank, as administrative agent (the
                  "Administrative Agent") and as auction administrative agent,
                  Citibank, N.A. and Fleet National Bank, as co-syndication
                  agents, and Bank of America, N.A. and Toronto Dominion
                  (Texas), Inc., as co-documentation agents.

         The Borrower has advised the Administrative Agent and the Lenders that
it desires to amend Sections 1.01, 4.01(a), and 4.01(b) of the Credit Agreement,
and has requested in connection therewith that the Credit Agreement be amended
as set forth in Section 1 below, and the parties hereto are so willing to amend
the Credit Agreement. Each capitalized term used but not defined herein and
defined in the Credit Agreement has the meaning assigned thereto in the Credit
Agreement.

         In consideration of the premises and the agreements and provisions
herein contained, the parties hereto hereby agree, on the terms and subject to
the conditions set forth herein, as follows:

         SECTION 1.        Amendment and Waiver. (a) Upon the effectiveness of
this Amendment No. 2 as provided in Section 3 below, the Credit Agreement shall
be amended as follows:

         (i) Section 1.01 of the Credit Agreement shall be amended to change the
         definition of "Majority Lenders." The defined term "Majority Lenders"
         shall be amended to read in its entirety as follows:

                  "MAJORITY LENDERS" means i) for purposes of acceleration of
                  the Advances and other amounts outstanding under Article 6
                  hereof, Lenders holding at least 51% of the then aggregate
                  unpaid principal amount of the Advances held by Lenders or
                  (ii) for all other purposes of this Agreement, Lenders having
                  at least 51% of the Commitments.

         (ii) Section 4.01 (a) of the Credit Agreement shall be amended to read
         in its entirety as follows:

                  The Borrower is a Business Entity duly formed, validly
                  existing and in good standing under the laws of the State of
                  Delaware. Each Material Subsidiary is duly organized, validly
                  existing and in good standing in the jurisdiction of its
                  formation. The Borrower and each Material Subsidiary possess
                  all applicable Business Entity powers and all other
                  authorizations and licenses necessary to engage in its
                  business and operations as now conducted, the
<PAGE>
                  failure to obtain or maintain which would have a Material
                  Adverse Effect. Each Subsidiary which is, on and as of the
                  Effective Date, a Material Subsidiary is listed on Schedule I
                  hereto.

         (iii) Section 4.01 (b) of the Credit Agreement shall be amended to read
         in its entirety as follows:

                  The execution, delivery and performance by the Borrower of
                  this Agreement and the Notes, if any, are within the
                  Borrower's applicable Business Entity powers, have been duly
                  authorized by all necessary applicable Business Entity action,
                  and do not contravene the Borrower's organizational documents
                  or law or any contractual restriction binding on or affecting
                  the Borrower.

         (iv) Section 5.01 of the Credit Agreement shall be amended to delete
         the word "Corporate" from the title thereof.

         (b)      The Lenders hereby waive any Default or Event of Default, if
any, arising under Section 4.01(a) or Section 4.01(b) of the Credit Agreement
that may exist or have existed at or prior to the date of effectiveness hereof
and that would not have existed had the amendments effected hereby been
effective at the time the Credit Agreement was originally executed and
delivered.

         SECTION 2.        Representations and Warranties. The Borrower
represents and warrants as of the effective date of this Amendment to each of
the Lenders that:

                  (a)      Immediately before and immediately after giving
         effect to this Amendment, the representations and warranties set forth
         in the Credit Agreement are true and correct in all material respects
         with the same effect as if made on the effective date hereof, except to
         the extent such representations and warranties expressly relate to an
         earlier date or period.

                  (b)      Immediately before and immediately after giving
         effect to this Amendment, no Event of Default or Default has occurred
         and is continuing that would not be cured by effectiveness of this
         Amendment No 2.

         SECTION 3.        Conditions to Effectiveness. This Amendment No. 2 and
the amendment and waiver contained herein shall become effective as of the date
hereof when the Administrative Agent shall have received counterparts of this
Amendment No. 2 that, when taken together, bear the signatures of the Borrower,
the Administrative Agent, and the Majority Lenders.

         SECTION 4.        Agreement. Except as specifically stated herein, the
provisions of the Credit Agreement are and shall remain in full force and
effect. As used therein, the terms "Credit Agreement", "herein", "hereunder",
"hereinafter", "hereto", "hereof" and words of similar import shall, unless the
context otherwise requires, refer to the Credit Agreement as amended hereby.

                                       2
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         SECTION 5.        Applicable Law. THIS AMENDMENT SHALL BE GOVERNED BY,
AND CONSTRUED IN ACCORDANCE WITH, THE LAWS OF THE STATE OF NEW YORK.

         SECTION 6.        Counterparts. This Amendment may be executed in two
or more counterparts, each of which shall constitute an original but all of
which when taken together shall constitute but one contract.

         SECTION 7.        Expenses. The Borrower agrees to reimburse the
Administrative Agent for all out-of-pocket expenses incurred by it in connection
with this Amendment, including the reasonable fees, charges and disbursements of
Cravath, Swaine & Moore, counsel for the Administrative Agent.

                                       3
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         IN WITNESS WHEREOF, the parties hereto have caused this Amendment to be
duly executed by their respective authorized officers as of the day and year
first written above.

                                         BURLINGTON RESOURCES INC.

                                         By: /s/ DANIEL D. HAWK
                                             ---------------------------------
                                             Name:  Daniel D. Hawk
                                             Title: Vice President & Treasurer
<PAGE>
                                            Signature page to the BURLINGTON
                                            RESOURCES INC. Amendment No. 2 to
                                            Long Term Revolving Credit Agreement
                                            dated as of February 25, 1998 as
                                            amended and restated as of December
                                            7, 2001 and as amended by Amendment
                                            No. 1 dated as of April 25, 2002

                                            JPMORGAN CHASE BANK, individually
                                            and as Administrative Agent and
                                            Auction Administrative Agent

                                            By: /s/ RUSSELL A. JOHNSON
                                                -------------------------------
                                                Name:  Russell A. Johnson
                                                Title: Vice President
<PAGE>
                                            Signature page to the BURLINGTON
                                            RESOURCES INC. Amendment No. 2 to
                                            Long Term Revolving Credit Agreement
                                            dated as of February 25, 1998 as
                                            amended and restated as of December
                                            7, 2001 and as amended by Amendment
                                            No. 1 dated as of April 25, 2002

                                            FLEET NATIONAL BANK, individually
                                            and as Co-Syndication Agent

                                            By: /s/ ALLISON I. ROSSI
                                                --------------------------------
                                                Name:  Allison I. Rossi
                                                Title: Director
<PAGE>
                                            Signature page to the BURLINGTON
                                            RESOURCES INC. Amendment No. 2 to
                                            Long Term Revolving Credit Agreement
                                            dated as of February 25, 1998 as
                                            amended and restated as of December
                                            7, 2001 and as amended by Amendment
                                            No. 1 dated as of April 25, 2002

                                            BANK OF AMERICA, N.A., individually
                                            and as Co-Documentation Agent

                                            By: /s/ RICHARD L. STEIN
                                                --------------------------------
                                                Name:  Richard L. Stein
                                                Title: Principal
<PAGE>
                                            Signature page to the BURLINGTON
                                            RESOURCES INC. Amendment No. 2 to
                                            Long Term Revolving Credit Agreement
                                            dated as of February 25, 1998 as
                                            amended and restated as of December
                                            7, 2001 and as amended by Amendment
                                            No. 1 dated as of April 25, 2002

                                            THE BANK OF NOVA SCOTIA

                                            By: /s/ N. BELL
                                                -------------------------------
                                                Name:  N. Bell
                                                Title: Assistant Agent
<PAGE>
                                            Signature page to the BURLINGTON
                                            RESOURCES INC. Amendment No. 2 to
                                            Long Term Revolving Credit Agreement
                                            dated as of February 25, 1998 as
                                            amended and restated as of December
                                            7, 2001 and as amended by Amendment
                                            No. 1 dated as of April 25, 2002

                                            BNP PARIBAS

                                            By: /s/ BRIAN M. MALONE
                                                --------------------------------
                                                Name:  Brian M. Malone
                                                Title: Managing Director

                                            By: /s/ POLLY SCHOTT
                                                --------------------------------
                                                Name:  Polly Schott
                                                Title: Vice President
<PAGE>
                                            Signature page to the BURLINGTON
                                            RESOURCES INC. Amendment No. 2 to
                                            Long Term Revolving Credit Agreement
                                            dated as of February 25, 1998 as
                                            amended and restated as of December
                                            7, 2001 and as amended by Amendment
                                            No. 1 dated as of April 25, 2002

                                            MELLON BANK, N.A.

                                            By: /s/ ROGER E. HOWARD
                                                --------------------------------
                                                Name:  Roger E. Howard
                                                Title: Vice President
<PAGE>
                                            Signature page to the BURLINGTON
                                            RESOURCES INC. Amendment No. 2 to
                                            Long Term Revolving Credit Agreement
                                            dated as of February 25, 1998 as
                                            amended and restated as of December
                                            7, 2001 and as amended by Amendment
                                            No. 1 dated as of April 25, 2002

                                            THE ROYAL BANK OF SCOTLAND PLC

                                            By: /s/ PAUL MCDONAGH
                                                --------------------------------
                                                Name:  Paul McDonagh
                                                Title: Sr. Vice President
<PAGE>
                                            Signature page to the BURLINGTON
                                            RESOURCES INC. Amendment No. 2 to
                                            Long Term Revolving Credit Agreement
                                            dated as of February 25, 1998 as
                                            amended and restated as of December
                                            7, 2001 and as amended by Amendment
                                            No. 1 dated as of April 25, 2002

                                            WACHOVIA BANK, NATIONAL ASSOCIATION

                                            By: /s/ PHILIP TRINDER
                                                --------------------------------
                                                Name:  Philip Trinder
                                                Title: Vice President
<PAGE>
                                            Signature page to the BURLINGTON
                                            RESOURCES INC. Amendment No. 2 to
                                            Long Term Revolving Credit Agreement
                                            dated as of February 25, 1998 as
                                            amended and restated as of December
                                            7, 2001 and as amended by Amendment
                                            No. 1 dated as of April 25, 2002

                                            ABN AMRO BANK

                                            By: /s/ FRANK R. RUSSO, JR.
                                                ------------------------------
                                                Name:  Frank R. Russo, Jr.
                                                Title: Group Vice President


                                            By: /s/ JEFFERY G. WHITE
                                                ------------------------------
                                                Name:  Jeffery G. White
                                                Title: Vice President
<PAGE>
                                            Signature page to the BURLINGTON
                                            RESOURCES INC. Amendment No. 2 to
                                            Long Term Revolving Credit Agreement
                                            dated as of February 25, 1998 as
                                            amended and restated as of December
                                            7, 2001 and as amended by Amendment
                                            No. 1 dated as of April 25, 2002

                                            THE BANK OF NEW YORK

                                            By: /s/ PETER W. KELLER
                                                -------------------------------
                                                Name:  Peter W. Keller
                                                Title: Vice President
<PAGE>
                                            Signature page to the BURLINGTON
                                            RESOURCES INC. Amendment No. 2 to
                                            Long Term Revolving Credit Agreement
                                            dated as of February 25, 1998 as
                                            amended and restated as of December
                                            7, 2001 and as amended by Amendment
                                            No. 1 dated as of April 25, 2002

                                            ROYAL BANK OF CANADA

                                            By: /s/ LORNE GARTNER
                                                --------------------------------
                                                Name:  Lorne Gartner
                                                Title: Vice President
<PAGE>
                                            Signature page to the BURLINGTON
                                            RESOURCES INC. Amendment No. 2 to
                                            Long Term Revolving Credit Agreement
                                            dated as of February 25, 1998 as
                                            amended and restated as of December
                                            7, 2001 and as amended by Amendment
                                            No. 1 dated as of April 25, 2002

                                            WELLS FARGO BANK TEXAS, N.A.

                                            By: /s/ PAUL A. SQUIRES
                                                ------------------------------
                                                Name:  Paul A. Squires
                                                Title: Vice President
<PAGE>
                                            Signature page to the BURLINGTON
                                            RESOURCES INC. Amendment No. 2 to
                                            Long Term Revolving Credit Agreement
                                            dated as of February 25, 1998 as
                                            amended and restated as of December
                                            7, 2001 and as amended by Amendment
                                            No. 1 dated as of April 25, 2002

                                            BANK ONE, N.A. (MAIN OFFICE,
                                            CHICAGO)

                                            By: /s/ THOMAS E. OKAMOTO
                                                -------------------------------
                                                Name:  Thomas E. Okamoto
                                                Title: Associate Director
<PAGE>
                                            Signature page to the BURLINGTON
                                            RESOURCES INC. Amendment No. 2 to
                                            Long Term Revolving Credit Agreement
                                            dated as of February 25, 1998 as
                                            amended and restated as of December
                                            7, 2001 and as amended by Amendment
                                            No. 1 dated as of April 25, 2002

                                            BARCLAYS BANK PLC

                                            By: /s/ NICHOLAS A. BELL
                                                ------------------------------
                                                Name:  Nicholas A. Bell
                                                Title: Director
                                                       Loan Transaction
                                                       Management
<PAGE>
                                            Signature page to the BURLINGTON
                                            RESOURCES INC. Amendment No. 2 to
                                            Long Term Revolving Credit Agreement
                                            dated as of February 25, 1998 as
                                            amended and restated as of December
                                            7, 2001 and as amended by Amendment
                                            No. 1 dated as of April 25, 2002

                                            CREDIT SUISSE FIRST BOSTON

                                            By: /s/ JAMES P. MORGAN
                                                --------------------------------
                                                Name:  James P. Morgan
                                                Title: Director

                                            By: /s/ IAN W. NALITT
                                                --------------------------------
                                                Name:  Ian W. Nalitt
                                                Title: Associate
<PAGE>
                                            Signature page to the BURLINGTON
                                            RESOURCES INC. Amendment No. 2 to
                                            Long Term Revolving Credit Agreement
                                            dated as of February 25, 1998 as
                                            amended and restated as of December
                                            7, 2001 and as amended by Amendment
                                            No. 1 dated as of April 25, 2002

                                            THE NORTHERN TRUST COMPANY

                                            By: /s/ ASHISH S. BHAGWAT
                                                -------------------------------
                                                Name:  Ashish S. Bhagwat
                                                Title: Vice President