Document:

<PAGE>
                                                                    EXHIBIT 10.5

[US AGENT WILL ADVISE THE TRANCHE B LENDERS OF THE DATE ON WHICH US BORROWER
EXECUTES AND DELIVERS THIS AMENDMENT TO US AGENT.]

                     FOURTH AMENDMENT TO US CREDIT AGREEMENT

     The Offer for Extension set forth in this Fourth Amendment to US Credit
Agreement (herein called this "Amendment") is made by Bank of America, N.A.,
individually and as administrative agent ("US Agent"), and the undersigned US
Lenders and shall be open for acceptance by Devon Energy Corporation, a Delaware
corporation ("US Borrower") until (and including) August 21, 2001.

                                   WITNESSETH:

     WHEREAS, US Borrower, US Agent and US Lenders have entered into that
certain US Credit Agreement dated as of August 29, 2000 (as amended,
supplemented, or restated to the date hereof, the "Original Agreement"), for the
purpose and consideration therein expressed, whereby US Lenders became obligated
to make loans to US Borrower as therein provided; and

     WHEREAS, pursuant to Section 1.1(c) of the Original Agreement, US Borrower
has delivered to US Agent a Request for Offer of Extension and a copy thereof
has been provided to all Tranche B Lenders; and

     WHEREAS, all of the Tranche B Lenders have agreed to accept such Request
for Offer of Extension; and

     WHEREAS, all of the Tranche B Lenders have agreed to extend the Tranche B
Revolving Period until the Tranche B Conversion Date as described in Section 2.1
of this Amendment and US Agent hereby makes an Offer of Extension to US Borrower
on such terms;

     NOW, THEREFORE, in consideration of the premises and the mutual covenants
and agreements contained herein and in the Original Agreement, in consideration
of the loans which may hereafter be made by US Lenders to US Borrower, and for
other good and valuable consideration, the receipt and sufficiency of which are
hereby acknowledged, the parties hereto do hereby agree as follows:

                                         Fourth Amendment to US Credit Agreement

<PAGE>

                                   ARTICLE I.

                           Definitions and References

     Section 1.1. Terms Defined in the Original Agreement. Unless the context
otherwise requires or unless otherwise expressly defined herein, the terms
defined in the Original Agreement shall have the same meanings whenever used in
this Amendment.

     Section 1.2. Other Defined Terms. Unless the context otherwise requires,
the following terms when used in this Amendment shall have the meanings assigned
to them in this section.

         "Amendment" means this Fourth Amendment to US Credit Agreement.

         "US Agreement" means the Original Agreement as amended hereby.

                                   ARTICLE II.

                        Amendments to Original Agreement

     Section 2.1. Defined Terms. The definition of "Tranche B Conversion Date"
in Annex I of the Original Agreement is hereby amended in its entirety to read
as follows:

          "'Tranche B Conversion Date' means the date which is 364 days after
     the date on which US Borrower executes and delivers to US Agent the Fourth
     Amendment to US Credit Agreement among US Borrower, US Agent and US
     Lenders, or such later day to which the Tranche B Conversion Date is
     extended pursuant to Section 1.1 of the US Agreement."

     Section 2.2. Waiver of Notice. Each Tranche B Lender hereby waives the
requirement under Section 1.1(c) of the Original Agreement that a Request for
Offer of Extension be made by a specific date prior to the current Tranche B
Conversion Date of August 28, 2001.

     Section 2.3. Lenders Schedule. Annex II to this Amendment is hereby
substituted for Annex II to the Original Agreement.

                                  ARTICLE III.

                           Conditions of Effectiveness

     Section 3.1. Effective Date. This Amendment shall become effective on the
date on which US Borrower has executed and delivered this Amendment to US Agent
(provided that US Borrower shall have executed this Amendment on or before
August 21, 2001) and the following additional conditions are satisfied:

                                       2

                                         Fourth Amendment to US Credit Agreement
<PAGE>

     (a) US Agent shall have received all of the following, at US Agent's
office, duly executed and delivered and in form and substance satisfactory to US
Agent, all of the following:

          (i) this Amendment executed by US Borrower, US Agent and all Tranche B
     Lenders;

          (ii) a certificate of the Senior Vice President - Finance or the
     Treasurer of US Borrower dated the date of this Amendment certifying: (i)
     that all of the representations and warranties set forth in Article IV
     hereof are true and correct at and as of such date, and (ii) that no
     Default exists at and as of such date.

     (b) US Borrower shall have paid, in connection with such US Loan Documents,
all fees and reimbursements to be paid to US Agent and US Lenders pursuant to
any US Loan Documents, or otherwise due US Agent or US Lenders and including
fees and disbursements of US Agent's attorneys.

     Section 3.2. Offer to Extend. The Offer to Extend set forth herein shall
be withdrawn and this Amendment shall be null and void if it is not executed and
delivered by US Borrower on or before August 21, 2001.

                                   ARTICLE IV.

                         Representations and Warranties

     Section 4.1. Representations and Warranties of US Borrower. In order to
induce each US Lender to enter into this Amendment, US Borrower represents and
warrants to each US Lender that:

     (a) The representations and warranties contained in Article V of the
Original Agreement are true and correct at and as of the time of the
effectiveness hereof, except to the extent that the facts on which such
representations and warranties are based have been changed by the extension of
credit under the US Agreement.

     (b) US Borrower is duly authorized to execute and deliver this Amendment
and is and will continue to be duly authorized to borrow monies and to perform
its obligations under the US Agreement. US Borrower has duly taken all corporate
action necessary to authorize the execution and delivery of this Amendment and
to authorize the performance of the obligations of US Borrower hereunder.

     (c) The execution and delivery by US Borrower of this Amendment, the
performance by US Borrower of its obligations hereunder and the consummation of
the transactions contemplated hereby do not and will not (i) conflict with any
provision of (A) any Law, (B) the organizational documents of US Borrower, or
(C) any agreement, judgment, license, order or permit applicable to or binding
upon US Borrower unless such conflict would not reasonably be

                                       3

                                         Fourth Amendment to US Credit Agreement
<PAGE>

expected to have a Material Adverse Effect, or (ii) result in or require the
creation of any Lien upon any assets or properties of US Borrower which would
reasonably be expected to have a Material Adverse Effect, except as expressly
contemplated or permitted in the Loan Documents. Except as expressly
contemplated in the Loan Documents no consent, approval, authorization or order
of, and no notice to or filing with, any Tribunal or third party is required in
connection with the execution, delivery or performance by US Borrower of this
Amendment or to consummate any transactions contemplated by this Amendment,
unless failure to obtain such consent would not reasonably be expected to have a
Material Adverse Effect.

     (d) When duly executed and delivered, each of this Amendment and the US
Agreement will be a legal and binding obligation of US Borrower, enforceable in
accordance with its terms, except as limited by bankruptcy, insolvency or
similar laws of general application relating to the enforcement of creditors'
rights and by equitable principles of general application.

     (e) The audited annual Consolidated financial statements of US Borrower
dated as of December 31, 2000 and the unaudited quarterly Consolidated financial
statements of US Borrower dated as of March 31, 2001 fairly present the
Consolidated financial position at such dates and the Consolidated statement of
operations and the changes in Consolidated financial position for the periods
ending on such dates for US Borrower. Copies of such financial statements have
heretofore been delivered to each US Lender. Since such dates no material
adverse change has occurred in the Consolidated financial condition or
businesses of US Borrower.

                                   ARTICLE V.

                                  Miscellaneous

     Section 5.1. Ratification of Agreements. The Original Agreement as hereby
amended is hereby ratified and confirmed in all respects. The US Loan Documents,
as they may be amended or affected by this Amendment, are hereby ratified and
confirmed in all respects. Any reference to the US Agreement in any Loan
Document shall be deemed to be a reference to the Original Agreement as hereby
amended. The execution, delivery and effectiveness of this Amendment shall not,
except as expressly provided herein, operate as a waiver of any right, power or
remedy of US Lenders under the US Agreement or any other US Loan Document nor
constitute a waiver of any provision of the US Agreement or any other US Loan
Document.

     Section 5.2. Survival of Agreements. All representations, warranties,
covenants and agreements of US Borrower herein shall survive the execution and
delivery of this Amendment and the performance hereof, including without
limitation the making or granting of the Loans, and shall further survive until
all of the Obligations are paid in full. All statements and agreements contained
in any certificate or instrument delivered by US Borrower or any Restricted
Person hereunder or under the US Agreement to any US Lender shall be deemed to
constitute representations and warranties by, and/or agreements and covenants
of, US Borrower under this Amendment and under the US Agreement.

                                       4

                                         Fourth Amendment to US Credit Agreement
<PAGE>

     Section 5.3. US Loan Documents. This Amendment is a US Loan Document, and
all provisions in the US Agreement pertaining to US Loan Documents apply hereto.

     Section 5.4. Governing Law. This Amendment shall be governed by and
construed in accordance the laws of the State of Texas and any applicable laws
of the United States of America in all respects, including construction,
validity and performance.

     Section 5.5. Counterparts; Fax. This Amendment may be separately executed
in counterparts and by the different parties hereto in separate counterparts,
each of which when so executed shall be deemed to constitute one and the same
Amendment. This Amendment may be validly executed by facsimile or other
electronic transmission.

     THIS AMENDMENT AND THE OTHER US 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 OF THE PARTIES.

         [The remainder of this page has been intentionally left blank.]

                                       5

                                         Fourth Amendment to US Credit Agreement
<PAGE>

     IN WITNESS WHEREOF, this Amendment is executed by US Borrower as of August
13, 2001.

                                       DEVON ENERGY CORPORATION
                                       US Borrower

                                       By: /s/ Dale T. Wilson
                                           -------------------------------------
                                           Dale T. Wilson
                                           Treasurer

                                         Fourth Amendment to US Credit Agreement
<PAGE>

     IN WITNESS WHEREOF, this Amendment is executed by US Agent and Tranche B
Lenders.

                                       BANK OF AMERICA, N.A.,
                                       Administrative Agent, US LC Issuer
                                       and Lender

                                       By: /s/ Angela McCracken
                                           -------------------------------------
                                           Name: Angela McCracken
                                           Title: Vice President

                                       ABN AMRO BANK, N.V.
                                       Lender

                                       By: Frank R. Russo, Jr.
                                           -------------------------------------
                                           Name: Frank R. Russo, Jr.
                                           Title: Group Vice President

                                       By: /s/ Jeffrey G.White
                                           -------------------------------------
                                           Name: Jeffrey G. White
                                           Title: Vice President

                                       BANCFIRST
                                       Lender

                                       By: /s/ Arthur B. Hobbs
                                           -------------------------------------
                                           Name: Arthur B. Hobbs
                                           Title: Vice President

                                       BANK ONE, NA
                                       Lender

                                       By: /s/ Ronald L. Dierker
                                           -------------------------------------
                                           Name: Ronald L. Dierker
                                           Title: Director, Capital Markets

                                         Fourth Amendment to US Credit Agreement
<PAGE>

                                       BAYERISCHE LANDESBANK
                                       GIROZENTRALE, CAYMAN ISLANDS
                                       BRANCH
                                       Lender

                                       By: /s/ Peter Obermann
                                           -------------------------------------
                                           Name: Peter Obermann
                                           Title: Senior Vice President

                                       By: /s/ James H. Boyle
                                           -------------------------------------
                                           Name: James H. Boyle
                                           Title: Vice President

                                       CIBC INC.
                                       Lender

                                       By: /s/ Nora Q. Catiis
                                           -------------------------------------
                                           Name: Nora Q. Catiis
                                           Title: Authorized Signatory

                                       CITIBANK, N.A.
                                       Lender

                                       By: /s/ Lydia G.Junek
                                           -------------------------------------
                                           Name: Lydia G. Junek
                                           Title: Attorney-in-fact

                                       CREDIT LYONNAIS NEW YORK BRANCH
                                       Lender

                                       By: /s/ Philippe Soustra
                                           -------------------------------------
                                           Name: Philippe Soustra
                                           Title: Executive Vice President

                                       CREDIT SUISSE FIRST BOSTON
                                       Lender

                                       By: /s/ Paul L. Colon
                                           -------------------------------------
                                           Name: Paul L. Colon
                                           Title: Vice President

                                       By: /s/ David M. Koczan
                                           -------------------------------------
                                           Name: David M. Koczan
                                           Title: Assistant Vice President

                                         Fourth Amendment to US Credit Agreement
<PAGE>

                                       DEUTSCHE BANK AG NEW YORK
                                       BRANCH AND/OR CAYMAN ISLANDS
                                       BRANCH
                                       Lender

                                       By: /s/ Michael E. Keating
                                           -------------------------------------
                                           Name: Michael E. Keating
                                           Title: Managing Director

                                       By: /s/ Joel Makowsky
                                           -------------------------------------
                                           Name: Joel Makowsky
                                           Title: Vice President

                                       FIRST UNION NATIONAL BANK
                                       Lender

                                       By: /s/ David E. Humphreys
                                           -------------------------------------
                                           Name: David E. Humphreys
                                           Title: Vice President

                                       ROYAL BANK OF CANADA
                                       Lender

                                       By: /s/ Lorne Gartner
                                           -------------------------------------
                                           Name: Lorne Gartner
                                           Title: Vice President

                                       SUNTRUST BANK, ATLANTA
                                       Lender

                                       By: /s/ David J. Edge
                                           -------------------------------------
                                           Name: David J. Edge
                                           Title: Director

                                       THE BANK OF NEW YORK
                                       Lender

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

                                         Fourth Amendment to US Credit Agreement
<PAGE>

                                      THE BANK OF TOKYO - MITSUBISHI
                                      LTD. HOUSTON AGENCY
                                      Lender

                                      By: /s/ K. Glasscock
                                          --------------------------------------
                                          Name: K. Glasscock
                                          Title: Vice President & Manager

                                      THE CHASE MANHATTAN BANK
                                      Lender

                                      By: /s/ Russell A. Johnson
                                          --------------------------------------
                                          Name: Russell A. Johnson
                                          Title: Vice President

                                      THE FUJI BANK, LIMITED
                                      Lender

                                      By: /s/ Jacques Azagury
                                          --------------------------------------
                                          Name: Jacques Azagury
                                          Title: Senior Vice President & Manager

                                      UBS AG, STAMFORD BRANCH
                                      Lender

                                      By: /s/ Susan Brunner
                                          --------------------------------------
                                          Name: Susan Brunner
                                          Title: Associate Director
                                                 Banking Products Services, US

                                      By: /s/ Patricia O'Kicki
                                          --------------------------------------
                                          Name: Director
                                          Title: Director
                                                 Banking Products Services

                                      UMB BANK
                                      Lender

                                      By: /s/ Derek K. Duncan
                                          --------------------------------------
                                          Name: Derek K. Duncan
                                          Title: Vice President

                                         Fourth Amendment to US Credit Agreement
<PAGE>

                                                                        ANNEX II

                                LENDERS SCHEDULE

                                         Fourth Amendment to US Credit Agreement
<PAGE>

                                                      Annex II - Lender Schedule

                                 BANK OF AMERICA

<Table>
<S>                                                                             <C>
US AGREEMENT

Name of Affiliate that is Lender under US Agreement                             Bank of America, N.A.

Applicable Lending Office for US Loans:                                         901 Main Street, 64th Floor
                                                                                Dallas, Texas 75202

Address for Notices:                                                            Three Allen Center
                                                                                333 Clay Street, Suite 4550
                                                                                Houston, Texas 77022-4103
                                                                                Attention:  James R. Allred

US TRANCHE A
         Tranche A Note Amount (5 year):                                        US$ 19,333,333.34
         Tranche A Percentage Share:                                            9.66666%

US TRANCHE B
         Tranche B Note Amount (364 day):                                       US$ 46,875,000.00
         Tranche B Percentage Share:                                            7.500%

CANADIAN AGREEMENT

Name of Affiliate that is Lender under Canadian Agreement:                      Bank of America Canada

                                                                                (CANADIAN RESIDENT LENDER)

Applicable Lending Office for Canadian Advances:                                200 Front Street West,
                                                                                Suite 2700
                                                                                Toronto, Ontario M5V3L2

Address for Notices:                                                            200 Front Street West,
                                                                                Suite 2700
                                                                                Toronto, Ontario M5V3L2
                                                                                Attention: Medina Sales de Andrade

CANADIAN FACILITY
         Canadian Note Amount:                                                  US$ 28,125,000.00
         Canadian Percentage Share:                                             7.500%

AGGREGATE COMMITMENT UNDER US AGREEMENT                                         US$ 60,000,000.00
AND CANADIAN AGREEMENT
</Table>

<PAGE>

                                                      Annex II - Lender Schedule

                               ABN AMRO BANK, N.V.

<Table>
<S>                                                                             <C>
US AGREEMENT

Name of Affiliate that is Lender under US Agreement:                            ABN AMRO Bank, N.V.

Applicable Lending Office for US Loans:                                         208 South
                                                                                LaSalle, Suite 1500
                                                                                Chicago, Illinois 60604-1003
                                                                                Attention: Loan Administration

Address for Notices:
                                                                                208 South LaSalle, Suite 1500
                                                                                Chicago, Illinois 60604-1003
                                                                                Attention: Loan Administration
                                                                            cc: Three Riverway Suite 1700
                                                                                Houston, Texas 77056
                                                                                Attention:  Frank R. Russo, Jr.

US TRANCHE A
         Not a Tranche A Lender

US TRANCHE B
         Tranche B Note Amount (364 day):                                       US$ 39,062,500.00
         Tranche B Percentage Share:                                            6.250%

CANADIAN AGREEMENT

Name of Affiliate that is Lender under Canadian Agreement:                      ABN AMRO Bank Canada

                                                                                (CANADIAN RESIDENT LENDER)

Applicable Lending Office for Canadian Advances:                                ABN AMRO Bank
                                                                                Canada
                                                                                79 Wellington St. West, 15th Floor
                                                                                Toronto, Ontario M5K 1G8

Address for Notices:                                                            ABN AMRO Bank Canada
                                                                                79 Wellington St. West, 15th Floor
                                                                                Toronto, Ontario M5K 1G8
                                                                                Attention: Yasmin Mohideen
                                                                            cc: Three Riverway Suite 1700
                                                                                Houston, Texas 77056
                                                                                Attention: Frank R. Russo, Jr.
CANADIAN FACILITY
         Canadian Note Amount:                                                  US$ 23,437,500.00
         Canadian Percentage Share:                                             6.250%

AGGREGATE COMMITMENT UNDER US AGREEMENT                                         US$ 50,000,000.00
AND CANADIAN AGREEMENT
</Table>

<PAGE>

                                                      Annex II - Lender Schedule

                                    BANCFIRST

<Table>
<S>                                                                             <C>
US AGREEMENT

Name of Affiliate that is Lender under US Agreement:                            BancFirst

Applicable Lending Office for US Loans:                                         101 N. Broadway
                                                                                Oklahoma City, Oklahoma 73102

Address for Notices:                                                            101 N. Broadway
                                                                                Oklahoma City, Oklahoma 73102
                                                                                Attention: Arthur B. Hobbs

US TRANCHE A
         Not a Tranche A Lender

US TRANCHE B
         Tranche B Note Amount (364 day):                                       US$  7,812,500.00
         Tranche B Percentage Share:                                            1.250%

CANADIAN AGREEMENT

Name of Affiliate that is Lender under Canadian Agreement:                      BancFirst

                                                                                (NON-RESIDENT LENDER)

Applicable Lending Office for Canadian Advances:                                101 N. Broadway
                                                                                Oklahoma City, Oklahoma 73102

Address for Notices:                                                            101 N. Broadway
                                                                                Oklahoma City, Oklahoma 73102
                                                                                Attention: Arthur B. Hobbs

CANADIAN FACILITY
         Canadian Note Amount:                                                  US$  4,687,500.00
         Canadian Percentage Share:                                             1.250%

AGGREGATE COMMITMENT UNDER US AGREEMENT                                         US$ 10,000,000.00
AND CANADIAN AGREEMENT
</Table>

<PAGE>

                                                      Annex II - Lender Schedule

                                BANK OF MONTREAL
                                [TRANCHE A ONLY]

<Table>
<S>                                                                             <C>
US AGREEMENT

Name of Affiliate that is Lender under US Agreement:                            Bank of Montreal

Applicable Lending Office for US Loans:                                         115 South La Salle
                                                                                11th Floor
                                                                                Chicago, Illinois 60603
                                                                                Attention: Loan Administration

Address for Notices:                                                            700 Louisiana, Suite 4400
                                                                                Houston, Texas 77002
                                                                                Attention: James Whitmore

US TRANCHE A
         Tranche A Note Amount (5 year):                                        US$ 16,000,000.00
         Tranche A Percentage Share:                                            8.0%

US TRANCHE B
         Not a Tranche B Lender

CANADIAN AGREEMENT

         Not a Canadian Lender
</Table>

<PAGE>

                                                      Annex II - Lender Schedule

                                    BANK ONE

<Table>
<S>                                                                             <C>
US AGREEMENT

Name of Affiliate that is Lender under US Agreement:                            Bank One, NA

Applicable Lending Office for US Loans:                                         1 Bank One Plaza
                                                                                Mail Code: IL1-0634
                                                                                Chicago, Illinois 60670

Address for Notices:                                                            1100 Louisiana, Suite 3200
                                                                                Houston, Texas 77002
                                                                                Attention: Ron Dierker

US TRANCHE A
         Tranche A Note Amount (5 year):                                        US$ 19,333,333.33
         Tranche A Percentage Share:                                            9.66666%

US TRANCHE B
         Tranche B Note Amount (364 day):                                       US$ 46,875,000.00
         Tranche B Percentage Share:                                            7.500%

CANADIAN AGREEMENT

Name of Affiliate that is Lender under Canadian Agreement:                      Bank One, NA, Canada Branch

                                                                                (CANADIAN RESIDENT LENDER)

Applicable Lending Office for Canadian Advances:                                161 Bay Street, Suite 4240
                                                                                Toronto, Ontario M5J 2S1

Address for Notices:                                                            1100 Louisiana, Suite 3200
                                                                                Houston, Texas 77002
                                                                                Attention: Ron Dierker

CANADIAN FACILITY
         Canadian Note Amount:                                                  US$ 28,125,000.00
         Canadian Percentage Share:                                             7.500%

AGGREGATE COMMITMENT UNDER US AGREEMENT                                         US$ 60,000,000.00
AND CANADIAN AGREEMENT
</Table>

<PAGE>

                                                      Annex II - Lender Schedule

                       BAYERISCHE LANDESBANK GIROZENTRALE

<Table>
<S>                                                                             <C>
US AGREEMENT

Name of Affiliate that is Lender under US Agreement:                            Bayerische Landesbank
                                                                                Girozentrale, Cayman Islands Branch

Applicable Lending Office for US Loans:                                         560 Lexington Avenue
                                                                                New York, New York 10022

Address for Notices:                                                            560 Lexington Avenue
                                                                                New York, New York 10022
                                                                                Attention: Stephen Christenson

US TRANCHE A
         Not a Tranche A Lender

US TRANCHE B
         Tranche B Note Amount (364 day):                                       US$ 31,250,000.00
         Tranche B Percentage Share:                                            5.000%

CANADIAN AGREEMENT

Name of Affiliate that is Lender under Canadian Agreement:                      Bayerische Landesbank Girozentrale,
                                                                                Toronto Branch

                                                                                (NON-RESIDENT LENDER)

Applicable Lending Office for Canadian Advances:                                BCE Place - Suite 3210
                                                                                181 Bay Street
                                                                                Toronto, Ontario M5J 2T3

Address for Notices:                                                            BCE Place - Suite 3210
                                                                                181 Bay Street
                                                                                Toronto, Ontario M5J 2T3
                                                                                Attention: Bernd Erpenbeck

CANADIAN FACILITY
         Canadian Note Amount:                                                  US$ 18,750,000.00
         Canadian Percentage Share:                                             5.000%

AGGREGATE COMMITMENT UNDER US AGREEMENT                                         US$ 40,000,000.00
AND CANADIAN AGREEMENT
</Table>

<PAGE>

                                                      Annex II - Lender Schedule

                                    CIBC INC.

<Table>
<S>                                                                             <C>
US AGREEMENT

Name of Affiliate that is Lender under US Agreement:                            CIBC Inc.

Applicable Lending Office for US Loans:                                         2 Paces West
                                                                                2727 Paces Ferry Road
                                                                                Suite 1200
                                                                                Atlanta, Georgia 30339
                                                                                Attention: Anita Rounds

Address for Notices:                                                            1600 Smith Street, Suite 3100
                                                                                Houston, Texas 77002
                                                                                Attention: Russell Otts

US TRANCHE A
         Tranche A Note Amount (5 year):                                        US$ 12,000,000.00
         Tranche A Percentage Share:                                            6.0%

US TRANCHE B
         Tranche B Note Amount (364 day):                                       US$ 19,531,250.00
         Tranche B Percentage Share:                                            3.125%

CANADIAN AGREEMENT

Name of Affiliate that is Lender under Canadian Agreement:                      Canadian Imperial Bank of Commerce

                                                                                (CANADIAN RESIDENT LENDER)

Applicable Lending Office for Canadian Advances:                                40 Dundas Street West
                                                                                5th Floor
                                                                                Toronto, Ontario M5G 2C2

Address for Notices:                                                            855 Second Street, S.W.
                                                                                10th Floor, Banker's Hall
                                                                                Calgary, Alberta T2P 4J7
                                                                                Attention: Joelle Schellenberg

CANADIAN FACILITY
         Canadian Note Amount:                                                  US$ 11,718,750.00
         Canadian Percentage Share:                                             3.125%

AGGREGATE COMMITMENT UNDER US AGREEMENT                                         US$ 25,000,000.00
AND CANADIAN AGREEMENT
</Table>

<PAGE>

                                                      Annex II - Lender Schedule

                                 CITIBANK, N.A.

<Table>
<S>                                                                             <C>
US AGREEMENT

Name of Affiliate that is Lender under US Agreement:                            Citibank, N.A.

Applicable Lending Office for US Loans:                                         399 Park Avenue
                                                                                New York, New York 10043

Borrowing Notices:                                                              Two Penn's Way, 2nd Floor
                                                                                New Castle Delaware 19720
                                                                                Attention: Sean L. Portrait

Address for Notices:                                                            1200 Smith Street, Suite 2000
                                                                                Houston, Texas 77002
                                                                                Attention: Todd J. Mogil

US TRANCHE A
         Tranche A Note Amount (5 year):                                        US$ 16,000,000.00
         Tranche A Percentage Share:                                            8.0%

US TRANCHE B
         Tranche B Note Amount (364 day):                                       US$ 39,062,500.00
         Tranche B Percentage Share:                                            6.250%

CANADIAN AGREEMENT

Name of Affiliate that is Lender under Canadian Agreement:                      Citibank Canada

                                                                                (CANADIAN RESIDENT LENDER)

Applicable Lending Office for Canadian Advances:                                400 Third Avenue SW, Suite 4210
                                                                                Calgary, Alberta T2P 4H2

Address for Notices:                                                            400 Third Avenue SW, Suite 4210
                                                                                Calgary, Alberta T2P 4H2
                                                                                Attention: Diane Gould
                                                                            cc: 1200 Smith Street, Suite 2000
                                                                                Houston, Texas 77002
                                                                                Attention: Todd J. Mogil

CANADIAN FACILITY
         Canadian Note Amount:                                                  US$ 23,437,500.00
         Canadian Percentage Share:                                             6.250%

AGGREGATE COMMITMENT UNDER US AGREEMENT                                         US$ 50,000,000.00
AND CANADIAN AGREEMENT
</Table>

<PAGE>

                                                      Annex II - Lender Schedule

                                 CREDIT LYONNAIS

<Table>
<S>                                                                             <C>
US AGREEMENT

Name of Affiliate that is Lender under US Agreement:                            Credit Lyonnais

Applicable Lending Office for US Loans:                                         1000 Louisiana Street
                                                                                Suite 5360
                                                                                Houston, Texas 77002

Address for Notices:                                                            1000 Louisiana Street
                                                                                Suite 5360
                                                                                Houston, Texas 77002
                                                                                Attention: John Grandstaff

US TRANCHE A
         Not a Tranche A Lender

US TRANCHE B
         Tranche B Note Amount (364 day):                                       US$ 31,250,000.00
         Tranche B Percentage Share:                                            5.000%

CANADIAN AGREEMENT

Name of Affiliate that is Lender under Canadian Agreement:                      Credit Lyonnais

                                                                                (NON-RESIDENT LENDER)

Applicable Lending Office for Canadian Advances:                                1000 Louisiana Street
                                                                                Suite 5360
                                                                                Houston, Texas 77002

Address for Notices:                                                            1000 Louisiana Street
                                                                                Suite 5360
                                                                                Houston, Texas 77002
                                                                                Attention: John Grandstaff

CANADIAN FACILITY
         Canadian Note Amount:                                                  US$ 18,750,000.00
         Canadian Percentage Share:                                             5.000%

AGGREGATE COMMITMENT UNDER US AGREEMENT                                         US$ 40,000,000.00
AND CANADIAN AGREEMENT
</Table>

<PAGE>

                                                      Annex II - Lender Schedule

                           CREDIT SUISSE FIRST BOSTON

<Table>
<S>                                                                             <C>
US AGREEMENT

Name of Affiliate that is Lender under US Agreement:                            Credit Suisse First Boston

Applicable Lending Office for US Loans:                                         Eleven Madison Avenue, 10th Floor
                                                                                New York, New York 10010-3629

Address for Notices:                                                            Eleven Madison Avenue, 10th Floor
                                                                                New York, New York 10010-3629
                                                                                Attention: James Moran

US TRANCHE A
         Not a Tranche A Lender

US TRANCHE B
         Tranche B Note Amount (364 day):                                       US$ 39,062,500.00
         Tranche B Percentage Share:                                            6.250%

CANADIAN AGREEMENT

Name of Affiliate that is Lender under Canadian Agreement:                      Credit Suisse First Boston Canada

                                                                                (CANADIAN RESIDENT LENDER)

Applicable Lending Office for Canadian Advances:                                1 First Canadian Place, Suite 3000
                                                                                P.O. Box 301
                                                                                Toronto, Ontario M5X 1C9

Address for Notices:                                                            1 First Canadian Place, Suite 3000
                                                                                P.O. Box 301
                                                                                Toronto, Ontario M5X 1C9
                                                                                Attention: Bill McFarland

CANADIAN FACILITY
         Canadian Note Amount:                                                  US$ 23,437,500.00
         Canadian Percentage Share:                                             6.250%

AGGREGATE COMMITMENT UNDER US AGREEMENT                                         US$ 50,000,000.00
AND CANADIAN AGREEMENT
</Table>

<PAGE>

                                                      Annex II - Lender Schedule

                                DEUTSCHE BANK AG

<Table>
<S>                                                                             <C>
US AGREEMENT

Name of Affiliate that is Lender under US Agreement:                            Deutsche Bank AG New York Branch
                                                                                and/or Cayman Islands Branch

Applicable Lending Office for US Loans:                                         31 West 52nd Street
                                                                                New York, New York 10019

Address for Notices:                                                            31 West 52nd Street
                                                                                New York, New York 10019
                                                                                Attention: Joel Makowsky

US TRANCHE A
         Tranche A Note Amount (5 year):                                        US$   9,333,333.33
         Tranche A Percentage Share:                                            4.66666%

US TRANCHE B
         Tranche B Note Amount (364 day):                                       US$ 39,062,500.00
         Tranche B Percentage Share:                                            6.250%

CANADIAN AGREEMENT

Name of Affiliate that is Lender under Canadian Agreement:                      Deutsche Bank AG New York Branch
                                                                                and/or Cayman Islands Branch

                                                                                (NON-RESIDENT LENDER)

Applicable Lending Office for Canadian Advances:                                31 West 52nd Street
                                                                                New York, New York 10019

Address for Notices:                                                            31 West 52nd Street
                                                                                New York, New York 10019
                                                                                Attention:  Joel Makowsky

CANADIAN FACILITY
         Canadian Note Amount:                                                  US$ 23,437,500.00
         Canadian Percentage Share:                                             6.250%

AGGREGATE COMMITMENT UNDER US AGREEMENT                                         US$ 50,000,000.00
AND CANADIAN AGREEMENT
</Table>

<PAGE>

                                                      Annex II - Lender Schedule

                            FIRST UNION NATIONAL BANK

<Table>
<S>                                                                             <C>
US AGREEMENT

Name of Affiliate that is Lender under US Agreement:                            First Union National Bank

Applicable Lending Office for US Loans:                                         1001 Fannin Street
                                                                                Suite 2255
                                                                                Houston, Texas 77002

Address for Notices:                                                            1001 Fannin Street
                                                                                Suite 2255
                                                                                Houston, Texas 77002
                                                                                Attention: David Humphreys

US TRANCHE A
         Tranche A Note Amount (5 year):                                        US$ 19,333,333.33
         Tranche A Percentage Share:                                            9.66666%

US TRANCHE B
         Tranche B Note Amount (364 day):                                       US$ 46,875,000.00
         Tranche B Percentage Share:                                            7.50%

CANADIAN AGREEMENT

Name of Affiliate that is Lender under Canadian Agreement:                      First Union National Bank

                                                                                (NON-RESIDENT LENDER)

Applicable Lending Office for Canadian Advances:                                1001 Fannin Street
                                                                                Suite 2255
                                                                                Houston, Texas 77002

Address for Notices:                                                            1001 Fannin Street
                                                                                Suite 2255
                                                                                Houston, Texas 77002
                                                                                Attention: David Humphreys

CANADIAN FACILITY
         Canadian Note Amount:                                                  US$ 28,125,000.00
         Canadian Percentage Share:                                             7.50%

AGGREGATE COMMITMENT UNDER US AGREEMENT                                         US$ 60,000,000.00
AND CANADIAN AGREEMENT
</Table>

<PAGE>

                                                      Annex II - Lender Schedule

                              ROYAL BANK OF CANADA

<Table>
<S>                                                                             <C>
US AGREEMENT

Name of Affiliate that is Lender under US Agreement:                            Royal Bank of Canada

Applicable Lending Office for US Loans:                                         One Liberty Plaza, 3rd Floor
                                                                                New York, New York 10006-1404

Address for Notices:                                                            One Liberty Plaza, 3rd Floor
                                                                                New York, New York 10006
                                                                                Attention: Manager, Loans Admin.
                                                                            cc: 2800 Post Oak Blvd., Suite 5700
                                                                                Houston, Texas 77056
                                                                                Attention: Lorne Gartner

US TRANCHE A
         Tranche A Note Amount (5 year):                                        US$ 16,000,000.00
         Tranche A Percentage Share:                                            8.0%

US TRANCHE B
         Tranche B Note Amount (364 day):                                       US$ 46,875,000.00
         Tranche B Percentage Share:                                            7.50%

CANADIAN AGREEMENT

Name of Affiliate that is Lender under Canadian Agreement:                      Royal Bank of Canada

                                                                                (CANADIAN RESIDENT LENDER)

Applicable Lending Office for Canadian Advances:                                One Liberty Plaza, 3rd Floor
                                                                                New York, New York 10006-1404
                                                                                Attention: Manager, Loans Admin.

Address for Notices:                                                            One Liberty Plaza, 3rd Floor
                                                                                New York, New York 10006-1404
                                                                                Attention: Manager, Loans Admin.
                                                                            cc: 2800 Post Oak Blvd., Suite 5700
                                                                                Houston, Texas 77056
                                                                                Attention: Lorne Gartner
CANADIAN FACILITY
         Canadian Note Amount:                                                  US$ 28,125,000.00
         Canadian Percentage Share:                                             7.50%

AGGREGATE COMMITMENT UNDER US AGREEMENT                                         US$ 60,000,000.00
AND CANADIAN AGREEMENT
</Table>

<PAGE>

                                                      Annex II - Lender Schedule

                             SUNTRUST BANK, ATLANTA

<Table>
<S>                                                                             <C>
US AGREEMENT

Name of Affiliate that is Lender under US Agreement:                            SunTrust Bank, Atlanta

Applicable Lending Office for US Loans:                                         303 Peachtree Street, N.E.
                                                                                Third Floor, M/C-1929
                                                                                Atlanta, Georgia 30308

Address for Notices:                                                            303 Peachtree Street, N.E.
                                                                                Third Floor, M/C-1929
                                                                                Atlanta, Georgia 30308
                                                                                Attention: David Edge

US TRANCHE A
         Tranche A Note Amount (5 year):                                        US$   6,666,666.67
         Tranche A Percentage Share:                                            3.33333%

US TRANCHE B
         Tranche B Note Amount (364 day):                                       US$ 11,718,750.00
         Tranche B Percentage Share:                                            1.875%

CANADIAN AGREEMENT

Name of Affiliate that is Lender under Canadian Agreement:                      SunTrust Bank, Atlanta

                                                                                (NON-RESIDENT LENDER)

Applicable Lending Office for Canadian Advances:                                303 Peachtree Street, N.E.
                                                                                Third Floor, M/C-1929
                                                                                Atlanta, Georgia 30308

Address for Notices:                                                            303 Peachtree Street, N.E.
                                                                                Third Floor, M/C-1929
                                                                                Atlanta, Georgia 30308
                                                                                Attention: David Edge

CANADIAN FACILITY
         Canadian Note Amount:                                                  US$   7,031,250.00
         Canadian Percentage Share:                                             1.875%

AGGREGATE COMMITMENT UNDER US AGREEMENT                                         US$ 15,000,000.00
AND CANADIAN AGREEMENT
</Table>

<PAGE>

                                                      Annex II - Lender Schedule

                              THE BANK OF NEW YORK

<Table>
<S>                                                                             <C>
US AGREEMENT

Name of Affiliate that is Lender under US Agreement:                            The Bank of New York

Applicable Lending Office for US Loans:                                         One Wall Street
                                                                                New York, New York 10286

Address for Notices:                                                            One Wall Street
                                                                                New York, New York 10286
                                                                                Attention: Raymond Palmer

US TRANCHE A
         Tranche A Note Amount (5 year):                                        US$ 12,000,000.00
         Tranche A Percentage Share:                                            6.0%

US TRANCHE B
         Tranche B Note Amount (364 day):                                       US$ 35,156,250.00
         Tranche B Percentage Share:                                            5.625%

CANADIAN AGREEMENT

Name of Affiliate that is Lender under Canadian Agreement:                      The Bank of New York

                                                                                (NON-RESIDENT LENDER)

Applicable Lending Office for Canadian Advances:                                One Wall Street
                                                                                New York, New York 10286

Address for Notices:                                                            One Wall Street
                                                                                New York, New York 10286
                                                                                Attention: Raymond Palmer

CANADIAN FACILITY
         Canadian Note Amount:                                                  US$ 21,093,750.00
         Canadian Percentage Share:                                             5.625%

AGGREGATE COMMITMENT UNDER US AGREEMENT                                         US$ 45,000,000.00
AND CANADIAN AGREEMENT
</Table>

<PAGE>

                                                      Annex II - Lender Schedule

                         THE BANK OF TOKYO - MITSUBISHI

<Table>
<S>                                                                             <C>
US AGREEMENT

Name of Affiliate that is Lender under US Agreement:                            The Bank of Tokyo - Mitsubishi Ltd.
                                                                                Houston Agency

Applicable Lending Office for US Loans:                                         1100 Louisiana Street
                                                                                Suite 2800
                                                                                Houston, Texas 77002-5216

Address for Notices:                                                            1100 Louisiana Street,
                                                                                Suite 2800
                                                                                Houston, Texas 77002-5216
                                                                                Attention: John M. McIntyre

US TRANCHE A
         Not a Tranche A Lender

US TRANCHE B
         Tranche B Note Amount (364 day):                                       US$ 31,250,000.00
         Tranche B Percentage Share:                                            5.000%

CANADIAN AGREEMENT

Name of Affiliate that is Lender under Canadian Agreement:                      Bank of Tokyo - Mitsubishi (Canada)

                                                                                (CANADIAN RESIDENT LENDER)

Applicable Lending Office for Canadian Advances:                                Suite 950 Park Place
                                                                                666 Burrard Street
                                                                                Vancouver, British Columbia V6C 3L1

Address for Notices:                                                            Suite 950 Park Place
                                                                                666 Burrard Street
                                                                                Vancouver, British Columbia V6C 3L1
                                                                                Attention: Davis Stewart

CANADIAN FACILITY
         Canadian Note Amount:                                                  US$ 18,750,000.00
         Canadian Percentage Share:                                             5.000%

AGGREGATE COMMITMENT UNDER US AGREEMENT                                         US$ 40,000,000.00
AND CANADIAN AGREEMENT
</Table>

<PAGE>

                                                      Annex II - Lender Schedule

                            THE CHASE MANHATTAN BANK

<Table>
<S>                                                                             <C>
US AGREEMENT

Name of Affiliate that is Lender under US Agreement:                            The Chase Manhattan Bank

Applicable Lending Office for US Loans:                                         600 Travis Street, 20th Floor
                                                                                Houston, Texas 77002-8086

Address for Notices:                                                            600 Travis Street, 20th Floor
                                                                                Houston, Texas 77002-8086
                                                                                Attention: Russell Johnson

US TRANCHE A  (The Chase Manhattan Bank)
         Tranche A Note Amount (5 year):                                        US$ 19,333,333.33
         Tranche A Percentage Share:                                            9.66666%

US TRANCHE A  (JP Morgan)
         Tranche A Note Amount (5 year):                                        US$ 12,000,000.00
         Tranche A Percentage Share:                                            6.0%

US TRANCHE B  (Combined Chase Manhattan Bank and JP Morgan)
         Tranche B Note Amount (364 day):                                       US$ 46,875,000.00
         Tranche B Percentage Share:                                            7.500%

CANADIAN AGREEMENT

Name of Affiliate that is Lender under Canadian Agreement:                      The Chase Manhattan Bank,
                                                                                Toronto Branch

                                                                                (NON-RESIDENT LENDER)

Applicable Lending Office for Canadian Advances:                                Royal Bank Plaza, South Tower
                                                                                200 Bay Street, Suite 1800
                                                                                Toronto, Ontario M5J 2J2

Address for Notices:                                                            Royal Bank Plaza, South Tower
                                                                                200 Bay Street, Suite 1800
                                                                                Toronto, Ontario M5J 2J2
                                                                                Attention:  Drew McDonald

CANADIAN FACILITY
         Canadian Note Amount:                                                  US$ 28,125,000.00
         Canadian Percentage Share:                                             7.500%

AGGREGATE COMMITMENT UNDER US AGREEMENT                                         US$ 60,000,000.00
AND CANADIAN AGREEMENT
</Table>

<PAGE>

                                                      Annex II - Lender Schedule

                         THE FUJI BANK, LIMITED (MIZUHO)

<Table>
<S>                                                                             <C>
US AGREEMENT

Name of Affiliate that is Lender under US Agreement:                            The Fuji Bank, Limited

Applicable Lending Office for US Loans:                                         Two World Trade Center
                                                                                79th Floor
                                                                                New York, New York 10048

Address for Notices:                                                            1221 McKinney Street
                                                                                Suite 4100
                                                                                Houston, Texas 77010
                                                                                Attention: Joseph Kankam

US TRANCHE A
         Not a Tranche A Lender

US TRANCHE B
         Tranche B Note Amount (364 day):                                       US$ 35,156,250.00
         Tranche B Percentage Share:                                            5.625%

CANADIAN AGREEMENT

Name of Affiliate that is Lender under Canadian Agreement:                      The Fuji Bank, Limited

                                                                                (NON-RESIDENT LENDER)

Applicable Lending Office for Canadian Advances:                                Two World Trade Center
                                                                                79th Floor
                                                                                New York, New York 10048

Address for Notices:                                                            1221 McKinney Street
                                                                                Suite 4100
                                                                                Houston, Texas 77010
                                                                                Attention: Joseph Kankam

CANADIAN FACILITY
         Canadian Note Amount:                                                  US$ 21,093,750.00
         Canadian Percentage Share:                                             5.625%

AGGREGATE COMMITMENT UNDER US AGREEMENT                                         US$ 45,000,000.00
AND CANADIAN AGREEMENT
</Table>

<PAGE>

                                                      Annex II - Lender Schedule

                              TORONTO-DOMINION BANK
                                [TRANCHE A ONLY]

<Table>
<S>                                                                             <C>
US AGREEMENT

Name of Affiliate that is Lender under US Agreement:                            Toronto-Dominion (Texas), Inc.

Applicable Lending Office for US Loans:                                         909 Fannin Street
                                                                                Suite 1700
                                                                                Houston, Texas 77010

Address for Notices:                                                            909 Fannin Street
                                                                                Suite 1700
                                                                                Houston, Texas 77010
                                                                                Attention: Mark Green

US TRANCHE A
         Tranche A Note Amount (5 year)                                         US$   6,666,666.67
         Tranche A Percentage Share:                                            3.33333%

US TRANCHE B
         Not a Tranche B Lender

CANADIAN AGREEMENT

         Not a Canadian Lender
</Table>

<PAGE>

                                                      Annex II - Lender Schedule

                                     UBS AG

<Table>
<S>                                                                             <C>
US AGREEMENT

Name of Affiliate that is Lender under US Agreement:                            UBS AG, Stamford Branch

Applicable Lending Office for US Loans:                                         677 Washington Boulevard
                                                                                Stamford, Connecticut 06901

Address for Notices:                                                            677 Washington Boulevard
                                                                                Stamford, Connecticut 06901
                                                                                Attention: Denise Denicola

US TRANCHE A
         Not a Tranche A Lender

US TRANCHE B
         Tranche B Note Amount (364 day):                                       US$ 19,531,250.00
         Tranche B Percentage Share:                                            3.125%

CANADIAN AGREEMENT

Name of Affiliate that is Lender under Canadian Agreement:                      UBS AG, Stamford Branch

                                                                                (NON-RESIDENT LENDER)

Applicable Lending Office for Canadian Advances:                                677 Washington Boulevard
                                                                                Stamford, Connecticut 06901

Address for Notices:                                                            677 Washington Boulevard
                                                                                Stamford, Connecticut 06901
                                                                                Attention: Denise Denicola

CANADIAN FACILITY
         Canadian Note Amount:                                                  US$ 11,718,750.00
         Canadian Percentage Share:                                             3.125%

AGGREGATE COMMITMENT UNDER US AGREEMENT                                         US$ 25,000,000.00
AND CANADIAN AGREEMENT
</Table>

<PAGE>

                                                      Annex II - Lender Schedule

                                    UMB BANK

<Table>
<S>                                                                             <C>
US AGREEMENT

Name of Affiliate that is Lender under US Agreement:                            UMB Bank

Applicable Lending Office for US Loans:                                         204 N. Robinson
                                                                                Oklahoma City, Oklahoma 73102

Address for Notices:                                                            204 N. Robinson
                                                                                Oklahoma City, Oklahoma 73102
                                                                                Attention: Richard Lehrter

US TRANCHE A
         Tranche A Note Amount (5 year):                                        US$   4,000,000.00
         Tranche A Percentage Share:                                            2.0%

US TRANCHE B
         Tranche B Note Amount (364 day):                                       US$ 11,718,750.00
         Tranche B Percentage Share:                                            1.875%

CANADIAN AGREEMENT

Name of Affiliate that is Lender under Canadian Agreement:                      UMB Bank

                                                                                (NON-RESIDENT LENDER)

Applicable Lending Office for Canadian Advances:                                204 N. Robinson
                                                                                Oklahoma City, Oklahoma 73102

Address for Notices:                                                            204 N. Robinson
                                                                                Oklahoma City, Oklahoma 73102
                                                                                Attention: Richard Lehrter

CANADIAN FACILITY
         Canadian Note Amount:                                                  US$   7,031,250.00
         Canadian Percentage Share:                                             1.875%

AGGREGATE COMMITMENT UNDER US AGREEMENT                                         US$ 15,000,000.00
AND CANADIAN AGREEMENT
</Table>

<PAGE>

                                                      Annex II - Lender Schedule

                      WESTDEUTSCHE LANDESBANK GIROZENTRALE
                                [TRANCHE A ONLY]

<Table>
<S>                                                                             <C>
US AGREEMENT

Name of Affiliate that is Lender under US Agreement:                            Westdeutsche Landesbank
                                                                                Girozentrale

Applicable Lending Office for US Loans:                                         1211 Avenue of the Americas
                                                                                New York, New York 10036

Address for Notices:                                                            1211 Avenue of the Americas
                                                                                New York, New York 10036
                                                                                Attention: Jeff Davidson

US TRANCHE A
         Tranche A Note Amount (5 year):                                        US$ 12,000,000.00
         Tranche A Percentage Share:                                            6.0%

US TRANCHE B
         Not a Tranche B Lender

CANADIAN AGREEMENT

         Not a Canadian lender.
</Table>

<PAGE>

                             COMPLIANCE CERTIFICATE

                            DEVON ENERGY CORPORATION

         Reference is made to that certain Fourth Amendment to US Credit
Agreement dated as of August 13, 2001 (the "Fourth Amendment"), among Devon
Energy Corporation ("US Borrower") and Bank of America, N.A., individually and
as administrative agent ("US Agent"), and certain financial institutions
("Lenders"). Terms which are defined in the Fourth Amendment and which are used
but not defined herein shall have the meanings given them in the Fourth
Amendment. The undersigned, Dale Wilson, does hereby certify that he has made a
thorough inquiry into all matters certified herein and, based upon such inquiry,
experience, and the advice of counsel, does hereby further certify that:

         1. He is the duly elected, qualified, and acting Treasurer of US
Borrower.

         2. All representations and warranties made by any Restricted Person in
any Loan Document delivered on or before the date hereof are true on and as of
the date hereof (except to the extent that the facts upon which such
representations are based have been changed by the transactions contemplated in
the Fourth Amendment) as if such representations and warranties had been made as
of the date hereof.

         3. No Default exists on the date hereof.

         4. Each Restricted Person has performed and complied with all
agreements and conditions required in the Loan Documents to be performed or
complied with by it on or prior to the date hereof.

         IN WITNESS WHEREOF, this instrument is executed by the undersigned as
of August 13, 2001.

                                                  /s/  Dale T. Wilson
                                                 ------------------------------
                                                  Dale Wilson, Treasurer

<PAGE>

                            ASSIGNMENT AND ACCEPTANCE
                              (US Credit Agreement)

     Reference is made to the US Credit Agreement dated as of August 29, 2000
(as amended, supplemented or otherwise modified from time to time, the "Credit
Agreement") among Devon Energy Corporation, a Delaware corporation (the "US
Borrower"), the US Lenders (as defined in the Credit Agreement) and Bank of
America, N.A., individually and as administrative agent for the Lenders (the "US
Agent"). Terms defined in the Credit Agreement are used herein with the same
meaning.

     Each of the "Assignors" and the "Assignees" referred to on Schedule 1 agree
as follows:

     1. Each Assignor hereby sells and assigns to the Assignees the portion of
its Tranche B Maximum Credit Amount specified opposite its name on Schedule 1
hereto and the related Tranche B Rights and Obligations (as hereinafter
defined), without recourse and without representation or warranty except as
expressly set forth herein, and each Assignee hereby purchases and assumes from
the Assignors the portion of the Tranche B Maximum Credit Amount specified
opposite its name on Schedule 1 hereto and the related Tranche B Rights and
Obligations. After giving effect to such sale and assignment, each Assignor's
Tranche B Maximum Credit Amount and the amount of Tranche B Loans owing to each
Assignor will be as set forth on Schedule 1 and each Assignee's Tranche B
Maximum Credit Amount and the amount of Tranche B Loans owing to each Assignee
will be as set forth on Schedule 1. As used herein, "Tranche B Rights and
Obligations" means all outstanding rights and obligations under the Credit
Agreement and the other US Loan Documents relating to the Tranche B Loans and
the Tranche B Maximum Credit Amount. This Assignment and Acceptance is subject
to Section 1.9 of the Credit Agreement. On the Effective Date under such Section
1.9, the amount allocated to the Tranche B Maximum Credit Amount is $525,000,000
and the amount allocated to the Canadian Maximum Credit Amount is $275,000,000.

     2. Each Assignor (i) represents and warrants that it is the legal and
beneficial owner of the interest being assigned by it hereunder and that such
interest is free and clear of any adverse claim; (ii) makes no representation or
warranty and assumes no responsibility with respect to any statements,
warranties or representations made in or in connection with the US Loan
Documents or the execution, legality, validity, enforceability, genuineness,
sufficiency or value of the US Loan Documents or any other instrument or
document furnished pursuant thereto; (iii) makes no representation or warranty
and assumes no responsibility with respect to the financial condition of any
Restricted Person or the performance or observance by any Restricted Person of
any of its obligations under the US Loan Documents or any other instrument or
document furnished pursuant thereto; and (iv) is delivering to US Agent its
Tranche B Note and requests that US Agent exchange such Tranche B Note for a new
Tranche B Note payable to the order of such Assignor in an amount equal to the
Tranche B Maximum Credit Amount retained by such Assignor as specified on
Schedule 1 and a new Tranche B Note payable to the order of the relevant
Assignee in an amount equal to the Tranche B Maximum Credit Amount of such
Assignee specified in Schedule 1.

<PAGE>

     3. Each Assignee (i) confirms that it has received a copy of the Credit
Agreement, together with copies of the financial statements referred to in
Section 6.2 thereof and such other documents and information as it has deemed
appropriate to make its own credit analysis and decision to enter into this
Assignment and Acceptance; (ii) agrees that it will, independently and without
reliance upon US Agent, the Assignors or any other Lender and based on such
documents and information as it shall deem appropriate at the time, continue to
make its own credit decisions in taking or not taking action under the Credit
Agreement; (iii) confirms that it is an Eligible Transferee; (iv) appoints and
authorizes US Agent to take such action as US Agent on its behalf and to
exercise such powers and discretion under the Credit Agreement as are delegated
to US Agent by the terms thereof, together with such powers and discretion as
are reasonably incidental thereto; (v) agrees that it will perform in accordance
with their terms all of the obligations that by the terms of the Credit
Agreement are required to be performed by it as a Lender; and (vi) attaches any
U.S. Internal Revenue Service or other forms required under Section 3.9.

     4. Following the execution of this Assignment and Acceptance, it will be
delivered to US Agent for acceptance and recording by US Agent. The effective
date for this Assignment and Acceptance (the "Effective Date") shall be August
9, 2001.

     5. Upon such acceptance and recording by US Agent, as of the Effective
Date, (i) the Assignees shall be parties to the Credit Agreement and, to the
extent provided in this Assignment and Acceptance, have the rights and
obligations of Tranche B Lenders thereunder and (ii) the Assignors shall, to the
extent provided in this Assignment and Acceptance, relinquish their rights and
be released from their obligations under the Credit Agreement.

     6. Upon such acceptance and recording by US Agent, from and after the
Effective Date, US Agent shall make all payments under the Credit Agreement and
the Tranche B Notes in respect of the interest assigned hereby (including,
without limitation, all payments of principal, interest and commitment fees with
respect thereto) to the appropriate Assignees. The Assignors and Assignees shall
make all appropriate adjustments in payments under the Credit Agreement and the
Tranche B Notes for periods prior to the Effective Date directly between
themselves.

     7. This Assignment and Acceptance shall be governed by, and construed in
accordance with, the Laws of the State of Texas.

     8. This Assignment and Acceptance may be executed in any number of
counterparts and by different parties hereto in separate counterparts, each of
which when so executed shall be deemed to be an original and all of which taken
together shall constitute one and the same agreement. Delivery of an executed
counterpart of this Assignment and Acceptance by telecopier shall be effective
as delivery of a manually executed counterpart of this Assignment and
Acceptance.

                                 Assignment and Acceptance (US Credit Agreement)
<PAGE>

     IN WITNESS WHEREOF, the Assignors and the Assignees have caused this
Assignment and Acceptance to be executed by their officers thereunto duly
authorized as of August 9, 2001.

ASSIGNORS:                             BANK OF AMERICA, N.A., as Assignor

                                       By: /s/ Angela McCracken
                                           -------------------------------------
                                           Name: Angela McCracken
                                           Title: Vice President

                                       ABN AMRO BANK, N.V., as Assignor

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

                                       By: /s/ Jeffrey G. White
                                           -------------------------------------
                                           Name: Jeffrey G. White
                                           Title: Vice President

                                       BANK ONE, NA, as Assignor

                                       By: /s/ Ronald L. Dierker
                                           -------------------------------------
                                           Name: Ronald L. Dierker
                                           Title: Director, Capital Markets

                                       CITIBANK, N.A., as Assignor

                                       By: /s/ Todd J. Mogil
                                           -------------------------------------
                                           Name: Todd J. Mogil
                                           Title: Attorney-in-fact

                                       FIRST UNION NATIONAL BANK,
                                       as Assignor

                                       By: /s/ David E. Humphreys
                                           -------------------------------------
                                           Name: David E. Humphreys
                                           Title: Vice President

                                 Assignment and Acceptance (US Credit Agreement)
<PAGE>

                                       MORGAN GUARANTY TRUST
                                       COMPANY OF NEW YORK, as Assignor

                                       By: /s/ Russell A. Johnson
                                           -------------------------------------
                                           Name: Russell A. Johnson
                                           Title: Vice President

                                       SUNTRUST BANK, ATLANTA,
                                       as Assignor

                                       By: /s/ David J. Edge
                                           -------------------------------------
                                           Name: David J. Edge
                                           Title: Director

                                       THE CHASE MANHATTAN BANK,
                                       as Assignor

                                       By: /s/  Russell A. Johnson
                                           -------------------------------------
                                           Name: Russell A. Johnson
                                           Title: Vice President

                                       UMB BANK, as Assignor

                                       By: /s/ Derek K. Duncan
                                           -------------------------------------
                                           Name: Derek K. Duncan
                                           Title: Vice President

                                 Assignment and Acceptance (US Credit Agreement)
<PAGE>

                                    WESTDEUTSCHE LANDESBANK
                                    GIROZENTRALE, as Assignor

                                    By: /s/ S. Battinelli
                                        ----------------------------------------
                                        Name: S. Battinelli
                                        Title: Managing Director

                                    By: /s/ Walter T. Duffy III
                                        ----------------------------------------
                                        Name: Walter T. Duffy III
                                        Title: Associate Director

ASSIGNEES:                          BANCFIRST, as Assignee

                                    By: /s/ Arthur B. Hobbs
                                        ----------------------------------------
                                        Name: Arthur B. Hobbs
                                        Title: Vice President

                                    BAYERISCHE LANDESBANK
                                    GIROZENTRALE, CAYMAN ISLANDS
                                    BRANCH, as Assignee

                                    By: /s/ Peter Obermann
                                        ----------------------------------------
                                        Name: Peter Obermann
                                        Title: Senior Vice President

                                    By: /s/ James H. Boyle
                                        ----------------------------------------
                                        Name: James H. Boyle
                                        Title: Vice President

                                    CIBC INC., as Assignee

                                    By: /s/ Nora Q. Catiis
                                        ----------------------------------------
                                        Name: Nora Q. Catiis
                                        Title: Authorized Signatory

                                    CREDIT LYONNAIS NEW YORK BRANCH, as Assignee

                                    By: /s/ Philippe Soustra
                                        ----------------------------------------
                                        Name: Philippe Soustra
                                        Title: Executive Vice President

                                 Assignment and Acceptance (US Credit Agreement)
<PAGE>

                                       CREDIT SUISSE FIRST BOSTON,
                                       as Assignee

                                       By: /s/ Paul L. Colon
                                           -------------------------------------
                                           Name: Paul L. Colon
                                           Title: Vice President

                                       By: /s/ David M. Koczan
                                           -------------------------------------
                                           Name: David M. Koczan
                                           Title: Assistant Vice President

                                       DEUTSCHE BANK AG NEW YORK
                                       BRANCH AND/OR CAYMAN ISLANDS
                                       BRANCH, as Assignee

                                       By: /s/  Michael E. Keating
                                           -------------------------------------
                                           Name: Michael E. Keating
                                           Title: Managing Director

                                       By: /s/ Joel Makowsky
                                           -------------------------------------
                                           Name: Joel Makowsky
                                           Title: Vice President

                                       ROYAL BANK OF CANADA, as Assignee

                                       By: /s/ Lorne Gartner
                                           -------------------------------------
                                           Name: Lorne Gartner
                                           Title: Vice President

                                       THE BANK OF TOKYO-MITSUBISHI,
                                       LTD, HOUSTON AGENCY, as Assignee

                                       By: /s/  K. Glasscock
                                           -------------------------------------
                                           Name: K. Glasscock
                                           Title: Vice President & Manager

                                       THE BANK OF NEW YORK, as Assignee

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

                                 Assignment and Acceptance (US Credit Agreement)
<PAGE>

                                      THE FUJI BANK, LIMITED, as Assignee

                                      By: /s/ Jacques Azagury
                                          --------------------------------------
                                          Name: Jacques Azagury
                                          Title: Senior Vice President & Manager

                                      UBS AG, STAMFORD BRANCH,
                                      as Assignee

                                      By: /s/ Wilfred V. Saint
                                          --------------------------------------
                                          Name: Wilfred V. Saint
                                          Title: Associate Director
                                                 Banking Products Services, US

                                      By: /s/  Patricia O'Kicki
                                          --------------------------------------
                                          Name: Patricia O'Kicki
                                          Title: Director
                                                 Banking Products Services

                                 Assignment and Acceptance (US Credit Agreement)
<PAGE>

ACCEPTED AND APPROVED,
as of the 9th day of August, 2001

BANK OF AMERICA, N.A.

By: /s/ James R. Allred
    -------------------------------
    Name: James R. Allred
    Title: Managing Director

APPROVED as of the 9th day of
August, 2001

DEVON ENERGY CORPORATION

By: /s/ Dale T. Wilson
    -------------------------------
    Name: Dale T. Wilson
    Title: Treasurer

                                 Assignment and Acceptance (US Credit Agreement)
<PAGE>

                                   SCHEDULE 1
                                       TO
                            ASSIGNMENT AND ACCEPTANCE
                              (US Credit Agreement)

                                                         Page 1 of Schedule 1 to
                                 Assignment and Acceptance (US Credit Agreement)
<PAGE>

<Table>
<Caption>
                                                                                                                       MAXIMUM
                             AMOUNT OF                                                                                AGGREGATE
                             TRANCHE B             NEW TRANCHE B                                                   COMMITMENT UNDER
                              MAXIMUM              MAXIMUM AMOUNT                              OUTSTANDING            U.S. CREDIT
                               AMOUNT             AFTER ASSIGNMENT         TRANCHE B            TRANCHE B            AGREEMENT AND
                              ASSIGNED           AND TRANCHE B NOTE       PERCENTAGE           LOANS AFTER          CANADIAN CREDIT
                              (IN U.S.                 AMOUNT             SHARE AFTER           ASSIGNMENT             AGREEMENT
    BANK NAME                 DOLLARS)            (IN U.S. DOLLARS)        ASSIGNMENT        (IN U.S. DOLLARS)     (IN U.S. DOLLARS)
    ---------                ---------           ------------------       -----------        -----------------     -----------------

<S>                          <C>                 <C>                      <C>                <C>                   <C>
ASSIGNORS:

Bank of America, N.A.        8,593,750.03              46,875,000             7.500%                  0              60,000,000.00

ABN AMRO Bank, N.V.          6,250,000.00              39,062,500             6.250%                  0              50,000,000.00

Bank One, NA                 8,593,750.03              46,875,000             7.500%                  0              60,000,000.00

Citibank, N.A.               6,250,000.00              39,062,500             6.250%                  0              50,000,000.00

First Union National Bank    8,593,750.03              46,875,000             7.500%                  0              60,000,000.00

JP Morgan Chase             34,375,000.03              46,875,000             7.500%                  0              60,000,000.00

SunTrust Bank                2,604,166.56              11,718,750             1.875%                  0              15,000,000.00

UMB Bank                       781,250.00              11,718,750             1.875%                  0              15,000,000.00

Westdeutsche Landesbank     34,375,000.00                       0                 0                   0                          0
</Table>

                                                         Page 2 of Schedule 1 to
                                 Assignment and Acceptance (US Credit Agreement)
<PAGE>

<Table>
<Caption>
                                                                                                                       MAXIMUM
                                  AMOUNT OF                                                                           AGGREGATE
                                  TRANCHE B            NEW TRANCHE B                                               COMMITMENT UNDER
                                   MAXIMUM             MAXIMUM AMOUNT                          OUTSTANDING            U.S. CREDIT
                                    AMOUNT            AFTER ASSIGNMENT       TRANCHE B          TRANCHE B            AGREEMENT AND
                                   ASSIGNED          AND TRANCHE B NOTE     PERCENTAGE         LOANS AFTER          CANADIAN CREDIT
                                   (IN U.S.                AMOUNT           SHARE AFTER         ASSIGNMENT             AGREEMENT
    BANK NAME                      DOLLARS)           (IN U.S. DOLLARS)      ASSIGNMENT      (IN U.S. DOLLARS)     (IN U.S. DOLLARS)
    ---------                     ---------          ------------------     -----------      -----------------     -----------------

<S>                               <C>                <C>                    <C>              <C>                   <C>

  ASSIGNEES:

  BancFirst                      7,812,500.00             7,812,500           1.250%                   0              10,000,000.00

  Bayerische Landesbank          1,562,500.00            31,250,000           5.000%                   0              40,000,000.00

  CIBC, Inc.                     1,562,500.00            19,531,250           3.125%                   0              25,000,000.00

  Credit Lyonnais                1,562,500.00            31,250,000           5.000%                   0              40,000,000.00

  Credit Suisse First Boston    39,062,500.00            39,062,500           6.250%                   0              50,000,000.00

  Deutsche Bank AG               7,291,666.66            39,062,500           6.250%                   0              50,000,000.00

  Royal Bank of Canada          12,500,000.00            46,875,000           7.500%                   0              60,000,000.00

  The Bank of New York             781,250.00            35,156,250           5.625%                   0              45,000,000.00

  The Bank of Tokyo -           13,281,250.00            31,250,000           5.000%                   0              40,000,000.00
  Mitsubishi

  The Fuji Bank, Limited         5,468,750.00            35,156,250           5.625%                   0              45,000,000.00
  (Mizuho)

  UBS AG                        19,531,250.00            19,531,250           3.125%                   0              25,000,000.00
</Table>

                                                         Page 3 of Schedule 1 to
                                 Assignment and Acceptance (US Credit Agreement)
<PAGE>

                            ASSIGNMENT AND ACCEPTANCE

     Reference is made to the US Credit Agreement dated as of August 29, 2000
(the "Credit Agreement") among Devon Energy Corporation, a Delaware corporation
(the "US Borrower"), the Lenders (as defined in the Credit Agreement) and Bank
of America, N.A., individually and as administrative agent for the Lenders (the
"US Agent"). Terms defined in the Credit Agreement are used herein with the same
meaning.

     The "Assignor" and the "Assignee" referred to on Schedule 1 agree as
follows:

     1. The Assignor hereby sells and assigns to the Assignee, without recourse
and without representation or warranty except as expressly set forth herein, and
the Assignee hereby purchases and assumes from the Assignor, an interest in and
to the Assignor's rights and obligations under the Credit Agreement and the
other US Loan Documents as of the date hereof equal to the percentage interest
specified on Schedule 1 of all outstanding rights and obligations under the
Credit Agreement and the other US Loan Documents relating to the Tranche B Loans
and the Tranche B Maximum Credit Amount.

After giving effect to such sale and assignment, the Assignee's Tranche B
Maximum Credit Amount and the amount of Tranche B Loans owing to Assignee will
be as set forth on Schedule 1.

     2. The Assignor (i) represents and warrants that it is the legal and
beneficial owner of the interest being assigned by it hereunder and that such
interest is free and clear of any adverse claim; (ii) makes no representation or
warranty and assumes no responsibility with respect to any statements,
warranties or representations made in or in connection with the US Loan
Documents or the execution, legality, validity, enforceability, genuineness,
sufficiency or value of the US Loan Documents or any other instrument or
document furnished pursuant thereto and (iii) makes no representation or
warranty and assumes no responsibility with respect to the financial condition
of any Restricted Person or the performance or observance by any Restricted
Person of any of its obligations under the US Loan Documents or any other
instrument or document furnished pursuant thereto.

     3. The Assignee (i) confirms that it has received a copy of the Credit
Agreement, together with copies of the financial statements referred to in
Section 6.2 thereof and such other documents and information as it has deemed
appropriate to make its own credit analysis and decision to enter into this
Assignment and Acceptance; (ii) agrees that it will, independently and without
reliance upon US Agent, the Assignor or any other Lender and based on such
documents and information as it shall deem appropriate at the time, continue to
make its own credit decisions in taking or not taking action under the Credit
Agreement; (iii) confirms that it is an Eligible Transferee; (iv) appoints and
authorizes US Agent to take such action as US Agent on its behalf

<PAGE>

and to exercise such powers and discretion under the Credit Agreement as are
delegated to US Agent by the terms thereof, together with such powers and
discretion as are reasonably incidental thereto; (v) agrees that it will perform
in accordance with their terms all of the obligations that by the terms of the
Credit Agreement are required to be performed by it as a Lender; and (vi)
attaches any U.S. Internal Revenue Service or other forms required under Section
3.9

     4. Following the execution of this Assignment and Acceptance, it will be
delivered to US Agent for acceptance and recording by US Agent. The effective
date for this Assignment and Acceptance (the "Effective Date") shall be August
8, 2001.

     5. Upon such acceptance and recording by US Agent, as of the Effective
Date, (i) the Assignee shall be a party to the Credit Agreement and, to the
extent provided in this Assignment and Acceptance, have the rights and
obligations of a Lender thereunder and (ii) the Assignor shall, to the extent
provided in this Assignment and Acceptance, relinquish its rights and be
released from its obligations under the Credit Agreement.

     6. Upon such acceptance and recording by US Agent, from and after the
Effective Date, US Agent shall make all payments under the Credit Agreement and
the US Notes in respect of the interest assigned hereby (including, without
limitation, all payments of principal, interest and commitment fees with respect
thereto) to the Assignee. The Assignor and Assignee shall make all appropriate
adjustments in payments under the Credit Agreement and the US Notes for periods
prior to the Effective Date directly between themselves.

     7. This Assignment and Acceptance shall be governed by, and construed in
accordance with, the Laws of the State of Texas.

     8. This Assignment and Acceptance may be executed in any number of
counterparts and by different parties hereto in separate counterparts, each of
which when so executed shall be deemed to be an original and all of which taken
together shall constitute one and the same agreement. Delivery of an executed
counterpart of Schedule 1 to this Assignment and Acceptance by telecopier shall
be effective as delivery of a manually executed counterpart of this Assignment
and Acceptance.

     IN WITNESS WHEREOF, the Assignor and the Assignee have caused Schedule 1 to
this Assignment and Acceptance to be executed by their officers thereunto duly
authorized as of the date specified thereon.

<PAGE>

                                   SCHEDULE 1
                                       to
                            ASSIGNMENT AND ACCEPTANCE

Tranche B Percentage Share assigned:                           100 %

Assignee's Tranche B Maximum Credit Amount:                    US $ 25,781,250

Aggregate outstanding principal amount
  of Tranche B Loans assigned:                                 US $ 0

                                       MORGAN GUARANTY TRUST
                                       COMPANY OF NEW YORK, as Assignor

                                       By: /s/ Russell A. Johnson
                                           -------------------------------------
                                           Name: Russell A. Johnson
                                           Title: Vice President

                                       THE CHASE MANHATTAN BANK, as Assignee

                                       By: /s/ Russell A. Johnson
                                           -------------------------------------
                                           Name: Russell A. Johnson
                                           Title: Vice President

Accepted
as of the 8th day of August, 2001

BANK OF AMERICA, N.A.

By: /s/ James R. Allred
    -------------------------------
    Name: James R. Allred
    Title: Managing Director<PAGE>
                                                                    EXHIBIT 10.6

                     FIFTH AMENDMENT TO US CREDIT AGREEMENT

         THIS FIFTH AMENDMENT TO US CREDIT AGREEMENT (herein called this
"Amendment") made as of September 21, 2001, by and among Devon Energy
Corporation, a Delaware corporation ("US Borrower"), Bank of America, N.A.,
individually and as administrative agent ("US Agent"), and the US Lenders party
to the Original Agreement defined below ("US Lenders").

                                   WITNESSETH:

         WHEREAS, US Borrower, US Agent and US Lenders entered into that certain
US Credit Agreement dated as of August 29, 2000 (as amended, supplemented, or
restated to the date hereof, the "Original Agreement"), for the purpose and
consideration therein expressed, whereby US Lenders became obligated to make
loans to US Borrower as therein provided;

         WHEREAS, US Borrower, US Agent and US Lenders desire to amend the
Original Agreement as set forth herein;

         NOW, THEREFORE, in consideration of the premises and the mutual
covenants and agreements contained herein and in the Original Agreement, in
consideration of the loans which may hereafter be made by US Lenders to US
Borrower, and for other good and valuable consideration, the receipt and
sufficiency of which are hereby acknowledged, the parties hereto do hereby agree
as follows:

                                   ARTICLE I.

                           Definitions and References

         Section 1.1. Terms Defined in the Original Agreement. Unless the
context otherwise requires or unless otherwise expressly defined herein, the
terms defined in the Original Agreement shall have the same meanings whenever
used in this Amendment.

         Section 1.2. Other Defined Terms. Unless the context otherwise
requires, the following terms when used in this Amendment shall have the
meanings assigned to them in this section.

                  "Amendment" means this Fifth Amendment to US Credit Agreement.
         Fifth Amendment to US Credit Agreement

                  "Amendment Fee" means a fee, payable to each US Lender which
         executes and delivers this Amendment before noon on September 21, 2001
         (unless extended by US Borrower), in the amount of five basis points
         (0.05%) of such US Lender's Percentage Share of the Tranche A Maximum
         Credit Amount and the Tranche B Maximum Credit Amount.

                                          Fifth Amendment to US Credit Agreement
<PAGE>

                  "Long Term Financing" means a senior unsecured bank facility
         in an amount not to exceed US $6,000,000,000 arranged by UBS Warburg
         LLC and Banc of America Securities LLC to finance the acquisition by US
         Borrower of Anderson Exploration Ltd. and/or Mitchell Energy &
         Development Corp. through wholly-owned Subsidiaries of US Borrower.

                  "US Agreement" means the Original Agreement as amended hereby.

                                   ARTICLE II.

                        Amendments to Original Agreement

         Section 2.1. Defined Terms.

         (a) The definitions of "Canadian Agent", "Canadian LC Issuer", Canadian
Lenders", Canadian Prime Rate", "Canadian Resident Lender", "Canadian Swing
Lender", "Canadian Swing Rate" and "Canadian US Dollar Base Rate" in Annex I to
the Original Agreement are hereby amended in their entirety to read as follows:

                  "Canadian Agent" means Bank of America Canada and its
         successors and assigns, as administrative agent under the Canadian
         Agreement.

                  "Canadian LC Issuer" means Bank of America Canada and its
         successors and assigns in its capacity as the issuer of Letters of
         Credit under the Canadian Agreement. Canadian Agent may, with the
         consent of Canadian Borrower and the Lender in question, appoint any
         Canadian Resident Lender hereunder as a Canadian LC Issuer in place of
         or in addition to Canadian Agent.

                  "Canadian Lenders" means each signatory to the Canadian
         Agreement (other than any Borrower), including Bank of America Canada
         and, upon the requirements of Section 2.5 of the Fifth Amendment to
         Canadian Credit Agreement, dated as of September 21, 2001, among
         Canadian Borrower, Canadian Agent and Canadian Lenders, being
         completed, Bank of America, N.A., acting through a Canadian branch in
         the capacity of a Canadian Lender and the Canadian Swing Lender
         hereunder, rather than as Canadian Agent and Canadian LC Issuer, and
         the successors of each such party as holder of a Canadian Note.

                  "Canadian Prime Rate" means on any day a fluctuating rate of
         interest per annum equal to the higher of (i) the rate of interest per
         annum most recently announced by Canadian Agent as its reference rate
         for Canadian Dollar commercial loans made to a Person in Canada; and
         (ii) Canadian Agent's Discount Rate for Bankers' Acceptances

                                       2

                                          Fifth Amendment to US Credit Agreement
<PAGE>

         having a maturity of thirty days plus the Applicable Margin. No
         Canadian Prime Rate charged by any Person shall ever exceed the Highest
         Lawful Rate.

                  "Canadian Resident Lender" means each Lender identified as
         such on Annex II to the Canadian Agreement or any Assignment and
         Acceptance executed by a new Lender, each being a Person that is (i)
         not a non-resident of Canada for the purposes of the Income Tax Act
         (Canada) or (ii) a Person that is an "authorized foreign bank" as
         defined in section 2 of the Bank Act (Canada) and in subsection 248(1)
         of the Income Tax Act (Canada) which will receive all amounts paid or
         credited to it under the Canadian Obligations in respect of its
         "Canadian banking business" the purposes of paragraph 212(13.3)(a)of
         the Income Tax Act (Canada).

                  "Canadian Swing Lender" means Bank of America Canada and its
         successors and assigns, in their individual capacities, as Canadian
         Swing Lender.

                  "Canadian Swing Rate" means on any day a fluctuating rate of
         interest per annum established from time to time by Canadian Swing
         Lender as its money market rate, which rate may not be the lowest rate
         of interest charged by Canadian Swing Lender to its customers, plus the
         Applicable Margin. The Canadian Swing Rate shall never exceed the
         Highest Lawful Rate.

                  "Canadian US Dollar Base Rate" means on any day, the rate per
         annum equal to the higher of (a) the Federal Funds Rate for such day
         plus one-half of one percent (0.5%) and (b) the rate of interest per
         annum most recently established by Canadian Agent as its reference rate
         for US Dollar commercial loans made to a Person in Canada. Any change
         in the Canadian US Dollar Base Rate due to a change in Canadian Agent's
         reference rate shall be effective on the effective date of such change.
         No Canadian US Dollar Base Rate charged by any Person shall ever exceed
         the Highest Lawful Rate.

                  "Schedule II BA Reference Banks" means the Lenders listed in
         Schedule II to the Bank Act (Canada) and the Lenders listed in Schedule
         III to the Bank Act (Canada) that are not subject to the restrictions
         and requirements referred to in subsection 524(2) of the Bank Act
         (Canada) as are, at such time, designated by Canadian Agent, with the
         prior consent of the Canadian Borrower (acting reasonably), as the
         Schedule II BA Reference Banks.

         (b) Clauses (o) and (x) of the definition of "Permitted Liens" in Annex
I to the Original Agreement are hereby amended in their entirety to read as
follows:

                  "(o)     Liens in respect of Indebtedness permitted by
                           Sections 7.1(b), 7.1(f) and 7.1(j), and Liens in
                           respect of Indebtedness permitted by Section 7.1(c),
                           but only to the extent that such Liens encumber the
                           assets expressly permitted to secure such
                           Indebtedness by the terms of Section 7.1(c);"

                                       3

                                          Fifth Amendment to US Credit Agreement
<PAGE>

                  "(x)     in addition to Liens permitted by clauses (a) through
                           (w) above, Liens on property or assets if the
                           aggregate Indebtedness secured thereby does not
                           exceed two percent (2%) of Consolidated Assets."

         Section 2.2. Indebtedness. Section 7.1 of the Original Agreement is
hereby amended as follows:

                  (i) Subsection (c) is hereby amended in its entirety to read
         as follows:

                           "(c) unsecured Liabilities owed among the Restricted
                  Persons; provided that Liabilities owed by any Restricted
                  Subsidiary (other than Canadian Borrower) to US Borrower may
                  be secured by any and all assets of such Restricted
                  Subsidiary."

                  (ii) A new subsection (m) is hereby substituted for the
         existing subsection (m) to read as follows:

                           "(m) Indebtedness in an aggregate principal amount
                  not to exceed $4,300,000,000 owed by a Nova Scotia unlimited
                  liability company and wholly-owned Subsidiary of US Borrower
                  formed for the purpose of obtaining financing for the
                  acquisition by US Borrower, directly or indirectly through its
                  Subsidiaries, of Anderson Exploration Ltd. and/or Mitchell
                  Energy & Development Corp. and/or for other general corporate
                  purposes; provided that prior to the incurrence of such
                  Indebtedness such Subsidiary shall have delivered (i) to US
                  Agent a guaranty of all of the US Obligations and an opinion
                  of counsel to such Subsidiary with respect to the
                  enforceability thereof, in each case in form and substance
                  reasonably acceptable to US Agent, and (ii) to Canadian Agent
                  a guaranty of all of the Canadian Obligations and an opinion
                  of counsel to such Subsidiary with respect to the
                  enforceability thereof, in each case in form and substance
                  reasonably acceptable to Canadian Agent."

                  (iii) The existing subsection (m) is renumbered as subsection
         (n) and reads as follows:

                           "(n) miscellaneous items of Indebtedness of all
                  Restricted Persons (other than US Borrower) not otherwise
                  permitted in subsections (a) through (m) which do not in the
                  aggregate exceed US $400,000,000 in principal amount at any
                  one time outstanding."

         Section 2.3. Limitation on Liens. Section 7.2 of the Original Agreement
is hereby amended by inserting the following sentence immediately after the
second sentence thereof:

         US Lenders acknowledge that all or any portion of the proceeds of the
         Indebtedness referred to in Section 7.1(m) may be held in escrow
         pending the completion of the acquisition of Anderson Exploration Ltd.
         and/or Mitchell Energy & Development Corp.,

                                       4

                                          Fifth Amendment to US Credit Agreement
<PAGE>

         that all or any portion of such proceeds may be released from escrow
         and used to effect either or both of such acquisitions or, in the event
         either or both of such acquisitions fails to close, to redeem or prepay
         Indebtedness referred to in Section 7.1(m), together with interest and
         premiums thereon and fees and expenses in connection therewith, and
         that no such escrow arrangement constitutes or shall be deemed to
         constitute a Lien for purposes of this Agreement.

         Section 2.4. Funded Debt to Total Capitalization. Section 7.7 of the
Original Agreement is hereby amended in its entirety to read as follows:

                  "Section 7.7. Funded Debt to Total Capitalization. The ratio
         of US Borrower's Consolidated Total Funded Debt to US Borrower's Total
         Capitalization will not exceed (i) seventy percent (70%) at the end of
         any Fiscal Quarter ending on or before June 30, 2002, or (ii)
         sixty-five percent (65%) at the end of any Fiscal Quarter thereafter."

                                  ARTICLE III.

                           Conditions of Effectiveness

         Section 3.1. Effective Date. Except for the amendment in Section 2.4
hereof, this Amendment shall become effective as of the date first above written
when and only when:

         (a) US Agent shall have received all of the following, at US Agent's
office, duly executed and delivered and in form and substance satisfactory to US
Agent, all of the following:

                  (i) this Amendment executed by US Borrower, US Agent and US
         Required Lenders;

                  (ii) a certificate of the Senior Vice President - Finance or
         the Treasurer of US Borrower dated the date of this Amendment
         certifying: (i) that all of the representations and warranties set
         forth in Article IV hereof are true and correct at and as of such date,
         and (ii) that no Default exists at and as of such date.

         (b) US Borrower shall have paid on or before such effective date to
each US Lender which executed and delivered this Amendment before noon on
September 21, 2001 (unless extended by US Borrower), such US Lenders Amendment
Fee and all other fees and reimbursements to be paid to US Agent and US Lenders
pursuant to any US Loan Documents, or otherwise due US Agent or US Lenders and
including fees and disbursements of US Agent's attorneys.

         Section 3.2. Effective Date of Section 2.4. The amendment in Section
2.4 of this Amendment shall become effective as of the date when and only as of
the date when:

         (a) The conditions set forth in Section 3.1 (a) and (b) above have been
satisfied; and

                                       5

                                          Fifth Amendment to US Credit Agreement
<PAGE>

         (b) The documentation governing the Long Term Financing shall have been
executed and delivered, the initial funding shall have been advanced thereunder,
and shares of Anderson Exploration Ltd. shall have been acquired by US Borrower
or a Restricted Subsidiary pursuant to US Borrower's offer to purchase the
shares of Anderson Exploration Ltd.

                                   ARTICLE IV.

                         Representations and Warranties

         Section 4.1. Representations and Warranties of US Borrower. In order to
induce each US Lender to enter into this Amendment, US Borrower represents and
warrants to each US Lender that:

         (a) The representations and warranties contained in Article V of the
Original Agreement are true and correct at and as of the time of the
effectiveness hereof, except to the extent that the facts on which such
representations and warranties are based have been changed by the extension of
credit under the US Agreement.

         (b) US Borrower is duly authorized to execute and deliver this
Amendment and is and will continue to be duly authorized to borrow monies and to
perform its obligations under the US Agreement. US Borrower has duly taken all
corporate action necessary to authorize the execution and delivery of this
Amendment and to authorize the performance of the obligations of US Borrower
hereunder.

         (c) The execution and delivery by US Borrower of this Amendment, the
performance by US Borrower of its obligations hereunder and the consummation of
the transactions contemplated hereby do not and will not (i) conflict with any
provision of (A) any Law, (B) the organizational documents of US Borrower, or
(C) any agreement, judgment, license, order or permit applicable to or binding
upon US Borrower unless such conflict would not reasonably be expected to have a
Material Adverse Effect, or (ii) result in or require the creation of any Lien
upon any assets or properties of US Borrower which would reasonably be expected
to have a Material Adverse Effect, except as expressly contemplated or permitted
in the Loan Documents. Except as expressly contemplated in the Loan Documents no
consent, approval, authorization or order of, and no notice to or filing with,
any Tribunal or third party is required in connection with the execution,
delivery or performance by US Borrower of this Amendment or to consummate any
transactions contemplated by this Amendment, unless failure to obtain such
consent would not reasonably be expected to have a Material Adverse Effect.

         (d) When duly executed and delivered, each of this Amendment and the US
Agreement will be a legal and binding obligation of US Borrower, enforceable in
accordance with its terms, except as limited by bankruptcy, insolvency or
similar laws of general application relating to the enforcement of creditors'
rights and by equitable principles of general application.

                                       6

                                          Fifth Amendment to US Credit Agreement
<PAGE>

         (e) The audited annual Consolidated financial statements of US Borrower
dated as of December 31, 2000 and the unaudited quarterly Consolidated financial
statements of US Borrower dated as of June 30, 2001 fairly present the
Consolidated financial position at such dates and the Consolidated statement of
operations and the changes in Consolidated financial position for the periods
ending on such dates for US Borrower. Copies of such financial statements have
heretofore been delivered to each US Lender. Since such dates no material
adverse change has occurred in the Consolidated financial condition or
businesses of US Borrower.

                                   ARTICLE V.

                                  Miscellaneous

         Section 5.1. Long Term Financing. Pursuant to Section 9.7 of the US
Agreement, US Lenders agreed that Bank of America and its Affiliates may engage
in any kind of banking, trust, financial advisory, underwriting or other
business with each of the Restricted Persons and their respective Affiliates as
though Bank of America were not the US Agent or the US LC Issuer hereunder and
without notice to or consent of Lenders. US Lenders acknowledged that, pursuant
to such activities, Bank of America or its Affiliates may receive information
regarding any Restricted Person or its Affiliates (including information that
may be subject to confidentiality obligations in favor of such Restricted Person
or such Affiliate) and that the US Agent shall be under no obligation to provide
such information to them. Although not required by the terms of the Original
Agreement, Bank of America hereby notifies US Lenders that USB AG, Stamford
Branch, UBS Warburg LLC, Bank of America and Banc of America Securities LLC have
agreed to provide the Long Term Financing and may provide additional services to
the Restricted Persons in connection with the acquisitions financed thereby.

         Section 5.2. Ratification of Agreements. The Original Agreement as
hereby amended is hereby ratified and confirmed in all respects. The US Loan
Documents, as they may be amended or affected by this Amendment, are hereby
ratified and confirmed in all respects. Any reference to the US Agreement in any
Loan Document shall be deemed to be a reference to the Original Agreement as
hereby amended. The execution, delivery and effectiveness of this Amendment
shall not, except as expressly provided herein, operate as a waiver of any
right, power or remedy of US Lenders under the US Agreement or any other US Loan
Document nor constitute a waiver of any provision of the US Agreement or any
other US Loan Document.

         Section 5.3. Survival of Agreements. All representations, warranties,
covenants and agreements of US Borrower herein shall survive the execution and
delivery of this Amendment and the performance hereof, including without
limitation the making or granting of the Loans, and shall further survive until
all of the Obligations are paid in full. All statements and agreements contained
in any certificate or instrument delivered by US Borrower or any Restricted
Person hereunder or under the US Agreement to any US Lender shall be deemed to
constitute representations and warranties by, and/or agreements and covenants
of, US Borrower under this Amendment and under the US Agreement.

                                       7

                                          Fifth Amendment to US Credit Agreement
<PAGE>

         Section 5.4. US Loan Documents. This Amendment is a US Loan Document,
and all provisions in the US Agreement pertaining to US Loan Documents apply
hereto.

         Section 5.5. Governing Law. This Amendment shall be governed by and
construed in accordance the laws of the State of Texas and any applicable laws
of the United States of America in all respects, including construction,
validity and performance.

         Section 5.6. Counterparts; Fax. This Amendment may be separately
executed in counterparts and by the different parties hereto in separate
counterparts, each of which when so executed shall be deemed to constitute one
and the same Amendment. This Amendment may be validly executed by facsimile or
other electronic transmission.

         THIS AMENDMENT AND THE OTHER US 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 OF THE PARTIES.

            [THE REMAINDER OF THIS PAGE IS INTENTIONALLY LEFT BLANK.]

                                       8

                                          Fifth Amendment to US Credit Agreement
<PAGE>

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

                                 DEVON ENERGY CORPORATION
                                 US Borrower

                                 By: /s/  Dale T. Wilson
                                     ------------------------------------------
                                     Dale T. Wilson
                                     Treasurer

                                 BANK OF AMERICA, N.A.,
                                 Administrative Agent, US LC Issuer
                                 and Lender

                                 By: /s/  James R. Allred
                                     ------------------------------------------
                                     Name:  James R. Allred
                                     Title: Managing Director

                                 ABN AMRO BANK, N.V.
                                 Lender

                                 By: /s/  Jeffery White
                                     ------------------------------------------
                                     Name:  Jeffery White
                                     Title: Vice President

                                 By: /s/  John Reed
                                     ------------------------------------------
                                     Name:  John Reed
                                     Title: Assistant Vice President

                                 BANCFIRST
                                 Lender

                                 By: /s/  Arthur B. Hobbs
                                     ------------------------------------------
                                     Name:  Arthur B. Hobbs
                                     Title: Vice President

                                 BANK OF MONTREAL
                                 Lender

                                 By: /s/  James V. Ducote
                                     ------------------------------------------
                                     Name:  James V. Ducote
                                     Title: Director

                                          Fifth Amendment to US Credit Agreement
<PAGE>

                                 BANK ONE, NA (Main Office - Chicago)
                                 Lender

                                 By: /s/ Jeanie C. Harman
                                     ------------------------------------------
                                     Name:  Jeanie C. Harman
                                     Title: First Vice President

                                 BAYERISCHE LANDESBANK
                                 GIROZENTRALE, CAYMAN ISLANDS
                                 BRANCH
                                 Lender

                                 By: /s/ Hereward Drummond
                                     ------------------------------------------
                                     Name:  Hereward Drummond
                                     Title: Senior Vice President

                                 By: /s/ James H. Boyle
                                     ------------------------------------------
                                     Name:  James H. Boyle
                                     Title: Vice President

                                 CIBC, INC.
                                 Lender

                                 By: /s/ Nora Q. Catiis
                                     ------------------------------------------
                                     Name:  Nora Q. Catiis
                                     Title: Authorized Signatory

                                 CITIBANK, N.A.
                                 Lender

                                 By: /s/  Todd J. Mogil
                                     ------------------------------------------
                                     Name:  Todd J. Mogil
                                     Title: Attorney-in-fact

                                 CREDIT LYONNAIS NEW YORK BRANCH
                                 Lender

                                 By: /s/  Bernard Weymuller
                                     ------------------------------------------
                                     Name:  Bernard Weymuller
                                     Title: Senior Vice President

                                          Fifth Amendment to US Credit Agreement
<PAGE>

                                  CREDIT SUISSE FIRST BOSTON
                                  Lender

                                  By: /s/  James P.Moran
                                      -----------------------------------------
                                      Name:  James P. Moran
                                      Title: Director

                                  By: /s/  David M. Koczan
                                      -----------------------------------------
                                      Name:  David M. Koczan
                                      Title: Assistant Vice President

                                  DEUTSCHE BANK AG NEW YORK
                                  BRANCH AND/OR CAYMAN ISLANDS
                                  BRANCH
                                  Lender

                                  By: /s/  Joel Makowsky
                                      -----------------------------------------
                                      Name:  Joel Makowsky
                                      Title: Vice President

                                  By: /s/  Hans C. Narberhaus
                                      -----------------------------------------
                                      Name:  Hans C. Narberhaus
                                      Title: Vice President

                                  FIRST UNION NATIONAL BANK
                                  Lender

                                  By: /s/  James M. Kopp
                                      -----------------------------------------
                                      Name: James M. Kopp
                                      Title: Managing Director

                                  ROYAL BANK OF CANADA
                                  Lender

                                  By: /s/ Lorne Gartner
                                      -----------------------------------------
                                      Name:  Lorne Gartner
                                      Title: Vice President

                                  SUNTRUST BANK, ATLANTA
                                  Lender

                                  By: /s/  David J. Edge
                                      -----------------------------------------
                                      Name:  David J. Edge
                                      Title: Director

                                          Fifth Amendment to US Credit Agreement
<PAGE>

                                  THE BANK OF NEW YORK
                                  Lender

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

                                  THE BANK OF TOKYO - MITSUBISHI LTD.
                                  HOUSTON AGENCY
                                  Lender

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

                                  THE CHASE MANHATTAN BANK
                                  Lender

                                  By: /s/  Russell A. Johnson
                                      -----------------------------------------
                                      Name:  Russell A. Johnson
                                      Title: Vice President

                                  THE FUJI BANK, LIMITED
                                  Lender

                                  By: /s/  Jacques Azagury
                                      -----------------------------------------
                                      Name:  Jacques Azagury
                                      Title: Senior Vice President & Manager

                                  TORONTO-DOMINION (TEXAS), INC.
                                  Lender

                                  By: /s/  Mark A. Baird
                                      -----------------------------------------
                                      Name:  Mark A. Baird
                                      Title: Vice President

                                          Fifth Amendment to US Credit Agreement
<PAGE>

                                  UBS AG, STAMFORD BRANCH
                                  Lender

                                  By: /s/  Patricia O'Kicki
                                      -----------------------------------------
                                      Name:  Patricia O'Kicki
                                      Title: Director - Banking Products
                                             Services

                                  By: /s/  Wilfred V. Saint
                                      -----------------------------------------
                                      Name:  Wilfred V. Saint
                                      Title: Associate Director -
                                             Banking Products Services, US

                                  UMB BANK
                                  Lender

                                  By: /s/  Richard J. Lehrter
                                      -----------------------------------------
                                      Name:  Richard J. Lehrter
                                      Title: Community Bank President

                                  WESTDEUTSCHE LANDESBANK
                                  GIROZENTRALE
                                  Lender

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

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

                                          Fifth Amendment to US Credit Agreement

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