<PAGE>
 
                                                                    EXHIBIT 10.6
                             AMENDED AND RESTATED
                               CREDIT AGREEMENT

                           Dated as of July 8, 1998

                                     Among

                     OCEAN ENERGY RESOURCES CANADA, LTD.,
                                as the Company,

                      THE CHASE MANHATTAN BANK OF CANADA,
                           as Administrative Agent,

                                      and

                          THE LENDERS PARTIES HERETO
<PAGE>
 
                               TABLE OF CONTENTS

<TABLE>
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                                                                                             Page
<S>                                                                                          <C>
Article I: Definitions and Accounting Matters................................................   1
  Section 1.01  Terms Defined Recitals.......................................................   1
  Section 1.02  Certain Defined Terms........................................................   1
  Section 1.03  Other Defined Terms..........................................................   5
  Section 1.04  Accounting Terms and Determinations..........................................   5

Article II: Commitments......................................................................   5
  Section 2.01  Loans and Bankers' Acceptances...............................................   5
  Section 2.02  Borrowings, Renewals, Conversions, and Issuances.............................   7
  Section 2.03  Changes of Commitments.......................................................   8
  Section 2.04  Commitment Fee and Other Fees................................................   9
  Section 2.05  Lending Offices..............................................................   9
  Section 2.06  Several Obligations..........................................................   9
  Section 2.07  Notes........................................................................   9
  Section 2.08  Prepayments..................................................................   9
  Section 2.09  Available Canadian Subcommitment.............................................  10
  Section 2.10  Acceptance Date Procedure....................................................  11
  Section 2.11  Purchase of Bankers' Acceptances.............................................  11
  Section 2.12  Payment of Bankers' Acceptances..............................................  11

Article III: Payments of Principal and Interest..............................................  12
  Section 3.01  Repayment of Loans...........................................................  12
  Section 3.02  Interest.....................................................................  12

Article IV: Payments; Pro Rata Treatment; Computations; Etc..................................  12
  Section 4.01  Payments.....................................................................  12
  Section 4.02  Pro Rata Treatment...........................................................  13
  Section 4.03  Computations.................................................................  13
  Section 4.04  Non-receipt of Funds by the Administrative Agent.............................  13
  Section 4.05  Sharing of Payments, Etc.....................................................  14
  Section 4.06  Interest Act (Canada)........................................................  15

Article V: Yield Protection and Illegality...................................................  15
  Section 5.01  Additional Costs.............................................................  15
  Section 5.02  Illegality...................................................................  16
  Section 5.03  Additional Cost in Respect of Tax............................................  16
  Section 5.04  Base Rate Loans pursuant to Sections 5.01 and 5.02...........................  17
  Section 5.05  Compensation.................................................................  17
  Section 5.06  Avoidance of Taxes and Additional Costs......................................  18
  Section 5.07  Limitation on Right to Compensation..........................................  18
  Section 5.08  Compensation Procedure.......................................................  18
</TABLE> 
                                       i
<PAGE>
 
<TABLE>
<CAPTION>
                                                                                             Page
<S>                                                                                          <C>
Article VI: Conditions Precedent.............................................................  19
  Section 6.01  Effectiveness................................................................  19
  Section 6.02  Subsequent Borrowings........................................................  20

Article VII: Representations and Warranties..................................................  21
  Section 7.01  Incorporation By Reference...................................................  21

Article VIII: Affirmative Covenants..........................................................  21
  Section 8.01  Incorporation By Reference...................................................  21

Article IX: Negative Covenants...............................................................  22
  Section 9.01  Affirmation of Certain Covenants in Article IX of the U. S. Credit Agreement.  22

Article X: Events of Default.................................................................  22
  Section 10.01 Events of Default............................................................  22

Article XI: The Administrative Agent.........................................................  23
  Section 11.01 Incorporation by Reference...................................................  23

Article XII: Miscellaneous...................................................................  23
  Section 12.01 Incorporation by Reference...................................................  23
  Section 12.02 Amendments, Etc..............................................................  23
  Section 12.03 Assignments and Participations...............................................  23
  Section 12.04 Survival.....................................................................  25
  Section 12.05 GOVERNING LAW; SUBMISSION TO JURISDICTION....................................  25
  Section 12.06 Effectiveness................................................................  26
  Section 12.07 Interpretation of Loan Documents.............................................  26
</TABLE>

Exhibit A - Form of Note
Exhibit B - Form of Bankers' Acceptances
Exhibit C - Form of Assignment and Acceptance
Exhibit D - Form of Borrowing Request

                                      ii
<PAGE>
 
     This AMENDED AND RESTATED CREDIT AGREEMENT dated as of July 8, 1998 is
among: OCEAN ENERGY RESOURCES CANADA, LTD., a company continued under the laws
of the Province of British Columbia (the "Company"); each of the lenders that is
a party hereto (individually, a "Lender" and, collectively, the "Lenders"); and
THE CHASE MANHATTAN BANK OF CANADA, as administrative agent for the Lenders (in
such capacity, together with its successors in such capacity, the
"Administrative Agent").

                                    RECITALS

     A.  The Company, the Administrative Agent and the lenders parties thereto
entered into that certain Credit Agreement dated as of March 27, 1998 (such
credit agreement, as amended, the "Prior Credit Agreement").

     B.  The Company has requested that the Administrative Agent and the Lenders
amend and restate the Prior Credit Agreement and make credit available to and on
behalf of the Company on the terms and conditions stated herein.

     C.  The Administrative Agent and the Lenders, subject to the terms and
conditions stated herein, are willing to make such credit facilities available.

     D. Subject to the terms and conditions set forth herein, the Administrative
Agent and the Lenders have agreed to make certain credit available to the
Company; and accordingly, the parties hereto agree as follows:

                ARTICLE I:   DEFINITIONS AND ACCOUNTING MATTERS

     SECTION 1.01  TERMS DEFINED RECITALS.  As used in this Agreement, the terms
defined in the Recitals shall have the meanings indicated in the Recitals.

     SECTION 1.02 CERTAIN DEFINED TERMS. As used herein including the Recitals,
the following terms shall have the following meanings (all terms defined in this
Article I or in other provisions of this Agreement in the singular to have the
same meanings when used in the plural and vice versa):

     "Acceptance Date" shall mean any Business Day on which a Bankers'
Acceptance is issued and accepted by the Accepting Lender.

     "Acceptance Exposure" means, at any time, the aggregate face amount of all
Bankers' Acceptances outstanding at such time for which the Company has not yet
reimbursed the Accepting Lenders.

     "Accepting Lender" shall mean, as to any Bankers' Acceptance, the
Administrative Agent or any other Lender which has accepted such Bankers'
Acceptance pursuant to the terms of this Agreement.

     "Additional Costs" shall have the meaning assigned to that term in 
Section 5.01.
<PAGE>
 
     "Aggregate Commitments" at any time shall equal the sum of the Commitments
of all of the Lenders.

     "Affected Loans" shall have the meaning assigned to that term in 
Section 5.04.

     "Agreement" shall mean this Amended and Restated Credit Agreement, as
amended, supplemented or modified from time to time.

     "Allocated Canadian Borrowing Base" shall mean the amount designated as
such by OEI-Delaware under Section 2.09 of the U. S. Credit Agreement.

     "Applicable Lending Office" shall mean, for each Lender, the lending office
of such Lender (or an Affiliate of such Lender) located in Canada designated on
the signature pages hereof or such other offices of such Lender (or of an
Affiliate of such Lender) located in Canada as such Lender may from time to time
specify to the Administrative Agent and the Company as the office at which its
Loans are to be made and maintained and Bankers' Acceptances are to be accepted.

     "Applicable Margin" shall mean:

     (a) with respect to Base Rate Loans:  the Applicable Margin for Base Rate
Loans that are Conventional Loans under the U. S. Credit Agreement plus the then
applicable Facility Fee Rate; provided, that if at any time, the Applicable
Margin for Base Rate Loans plus the Base Rate is less than the Applicable Margin
for Bankers' Acceptances plus the Discount Rate for Bankers' Acceptances having
an Interest Period of 30 days, the Applicable Margin for Base Rate Loans shall
be increased so that the Applicable Margin for Base Rate Loans plus the Base
Rate will be not less than the Applicable Margin for Bankers' Acceptances plus
the Discount Rate for Bankers' Acceptances having an Interest Period of 30 days;
and

     (b) with respect to Bankers' Acceptances:  the Applicable Margin for
Eurodollar Loans that are Conventional Loans under the U. S. Credit Agreement
plus the then applicable Facility Fee Rate.

     "Assignment and Acceptance" shall have the meaning assigned such term in
Section 12.03(b).

     "Available Proceeds" shall mean the face amount of the Bankers' Acceptance
less the applicable Discount Amount and the Stamping Fee.

     "Bankers' Acceptance" shall mean a bill of exchange drawn by the Company in
Canadian Dollars, duly completed and accepted by a Lender, in a form customarily
used by the Administrative Agent in creating bankers' acceptances and which
otherwise meets any requirements of the Administrative Agent.

     "Base Rate" shall mean, with respect to any Base Rate Loan, for any day,
the rate equal to the Prime Rate for such day.  Each change in any interest rate
provided for herein based upon the Base Rate resulting from a change in the Base
Rate shall take effect at the time of such change in the Base Rate.

                                       2
<PAGE>
 
     "Base Rate Loans" shall mean loans which bear interest at the Base Rate.

     "Borrowing" shall mean a utilization of the Commitments by way of Loans or
by the issuance, acceptance and purchase of Bankers' Acceptances.

     "Business Day" shall mean any day on which commercial banks are not
authorized or required to close in Toronto, Canada or Calgary, Canada.

     "Chase" shall mean The Chase Manhattan Bank of Canada.

     "Commitment" shall mean, as to each Lender, the obligation of such Lender
to make Loans to the Company or accept Bankers' Acceptances from the Company in
an aggregate amount at any one time outstanding equal to the amount set forth
opposite such Lender's name on Annex I to the U. S. Credit Agreement under the
caption "Canadian Subcommitment" (as the same may be reduced from time to time
pursuant to Section 2.03 or modified pursuant to Assignment and Acceptances
pursuant to Section 12.03(b)).

     "Commitment Percentage" shall mean, as to any Lender, the percentage of the
Commitments to be provided by such Lender under this Agreement as indicated on
Annex I to the U. S. Credit Agreement as the Canadian Commitment Percentage, as
modified from time to time to reflect any assignments permitted by 
Section 12.03(b), such percentage being the quotient of such Lender's 
Commitment divided by the aggregate Commitments for all Lenders.

     "Discount Amount" shall mean, with respect to any Bankers' Acceptance, an
amount equal to the face amount thereof multiplied by the Discount Rate.

     "Discount Rate" shall mean at any time, with respect to any Bankers'
Acceptance, the then current bid rate in effect quoted by the Administrative
Agent on such day, which shall be a Business Day, for purchase by the
Administrative Agent of bankers' acceptances of the same face amount and having
maturities on the same date as the maturity date of such Bankers' Acceptance.

     "Dollars" and "$" shall mean Canadian Dollars.

     "Effective Date" shall have the meaning assigned such term in 
Section 12.06.

     "Guarantors" shall mean OEI-Delaware and OEI-Louisiana.

     "Guaranty Agreements" shall mean an agreement executed by each of the
Guarantors in form and substance satisfactory to the Administrative Agent
guarantying payment of the Indebtedness.

     "Indebtedness" shall mean any and all amounts owing or to be owing by the
Company or the Guarantors to the Administrative Agent, and/or the Lenders in
connection with the Notes, any Bankers' Acceptance or any other Loan Document,
including this Agreement and all renewals, extensions and/or rearrangements
thereof.

                                       3
<PAGE>
 
     "Insolvency Event" shall mean any of the Events of Default described in
Section 10.01(f), (g) or (h) of the U. S. Credit Agreement.

     "Interest Period" shall mean, with respect to any Bankers' Acceptances, the
period (which shall be 30 days, 60 days, 90 days, and subject to availability,
180 days, or such other period longer than 90 days requested by the Company and
agreed to by all the Lenders) commencing on the date such Bankers' Acceptance is
issued, accepted and purchased.

Notwithstanding the foregoing (unless otherwise agreed to by the Company and all
of the Lenders) each Interest Period which would otherwise end on a day which is
not a Business Day shall end on the next succeeding Business Day.

     "Loan Documents" shall mean this Agreement, the Notes, the Bankers'
Acceptances, the Guaranty Agreements, and all instruments, documents and
agreements which are "Loan Documents" under the U. S. Credit Agreement, and any
and all other agreements or instruments now or hereafter executed and delivered
by OEI-Delaware or any of its Subsidiaries, including the Company, or any other
Person (other than participation or similar agreements between any Lender and
any other lender or creditor with respect to any Indebtedness pursuant to this
Agreement) in connection with, or as security for the payment or performance of,
the Notes or this Agreement, as such agreements may be amended or supplemented
from time to time.

     "Loans" shall have the meaning assigned to that term in Section 2.01.

     "Note" shall mean a promissory note issued by the Company described in
Section 2.07(a) payable to the order of any Lender and being substantially in
the form of Exhibit A evidencing the aggregate Loans to the Company by such
Lender.

     "OEI-Delaware" shall mean Ocean Energy, Inc., a Delaware corporation, as
successor by merger to United Meridian Corporation.

     "OEI-Louisiana" shall mean Ocean Energy, Inc., a Louisiana corporation, as
successor by merger to UMC Petroleum Corporation.

     "Prime Rate" shall mean the rate of interest from time to time announced by
the Administrative Agent at the Principal Office as its prime commercial lending
rate for loans in Canadian Dollars made in Canada.  Such rate is set by the
Administrative Agent as a general reference rate of interest, taking into
account such factors as the Administrative Agent may deem appropriate, it being
understood that many of the Administrative Agent's commercial or other loans are
priced in relation to such rate, that it is not necessarily the lowest or best
rate actually charged to any customer and that the Administrative Agent may make
various commercial or other loans at rates of interest having no relationship to
such rate.

     "Principal Office" shall mean the principal office of the Administrative
Agent and Chase in Canada, presently located in Toronto, Ontario, Canada.

     "Regulatory Change" shall mean, with respect to any Lender, any change
after the date of this Agreement in United States Federal, Canadian, state,
provincial, or foreign law or regulations or the adoption or making after such
date of any interpretations, directives or requests 

                                       4
<PAGE>
 
applying to a class of lenders or insurance companies (including such Lender or
its Applicable Lending Office) of or under any United States Federal, Canadian,
state, provincial or foreign law or regulations (whether or not having the force
of law) by any court or governmental or monetary authority charged with the
interpretation or administration thereof.

     "Required Payment" shall have the meaning assigned to that term in 
Section 4.04.

     "Stamping Fee" shall mean, with respect to any Bankers' Acceptance, an
amount equal to the face amount thereof multiplied by the Applicable Margin for
Bankers' Acceptances.

     "U.S. Administrative Agent" shall mean Chase Bank of Texas, National
Association as Administrative Agent for the U.S. Lenders, together with its
successors in such capacity.

     "U.S. Commitments" shall mean the "Commitments" as defined in the U. S.
Credit Agreement.

     "U.S. Indebtedness" shall mean all Indebtedness as defined in the U. S.
Credit Agreement.

     "U.S. Lenders" shall mean the "Lenders" as defined in the U. S. Credit
Agreement.

     "U.S. Credit Agreement" shall mean that certain Amended and Restated Global
Credit Agreement of even date herewith, among OEI-Delaware, as borrower, Chase
Bank of Texas, National Association, as Administrative Agent, Morgan Guaranty
Trust Company of New York, as Syndication Agent, Barclays Bank PLC, as
Documentation Agent, and ABN Amro Bank, N.V., Bank of America National Trust &
Savings Association, Paribas, NationsBank, N.A., Societe Generale, Southwest
Agency and Wells Fargo Bank (Texas), N.A., as Co-Agents, and the lenders parties
thereto, as amended, restated, supplemented or modified from time to time.

     SECTION 1.03  OTHER DEFINED TERMS.  All other capitalized terms not defined
herein shall have the meanings assigned such terms in the U. S. Credit
Agreement.

     SECTION 1.04 ACCOUNTING TERMS AND DETERMINATIONS. Unless otherwise
specified herein, all accounting terms used herein shall be interpreted, all
determinations with respect to accounting matters hereunder shall be made, and
all financial statements and certificates and reports as to financial matters
required to be furnished to the Administrative Agent or the Lenders hereunder
shall be prepared, in accordance with Canadian generally accepted accounting
principles as in effect, applied on a basis consistent with the audited
consolidated financial statements of the Company and the consolidated
Subsidiaries referred to in Section 7.02 (except for changes concurred with by
the Company's independent public accountants).

                           ARTICLE II:   COMMITMENTS

     SECTION 2.01  LOANS AND BANKERS' ACCEPTANCES.

     (a) LOANS. Each Lender severally agrees, on the terms and conditions of
this Agreement, to make to the Company during the period from and including the
Effective Date to and including the Termination Date, revolving credit loans
(the "Loans") in an aggregate 

                                       5
<PAGE>
 
principal amount at any one time out-standing up to, but not exceeding, the
amount of such Lender's Commitment as then in effect; provided, that the
aggregate principal amount of (i) all Loans made by each Lender shall not exceed
(1) such Lender's Commitment Percentage of the Available Canadian Subcommitment
minus (2) such Lender's Acceptance Exposure and (ii) all Loans made by all
Lenders hereunder at any one time outstanding shall not exceed the Available
Canadian Subcommitment, as then in effect, minus the aggregate amount of
Acceptance Exposure for all Lenders. Subject to the terms of this Agreement,
during the period from the Effective Date to and including the Termination Date,
the Company may borrow, repay and reborrow the amount of the Commitments, as
then in effect.

     (b) BANKERS' ACCEPTANCES. Each Lender severally agrees, on the terms and
conditions of this Agreement, to accept and, immediately thereafter, purchase
Bankers' Acceptances from the Company from and after the Effective Date with a
maturity or Interest Period not beyond the Termination Date in an aggregate
amount at any one time outstanding up to, but not exceeding, the amount of such
Lenders' Commitment as then in effect; provided, that the Acceptance Exposure at
any one time (i) for each Lender shall not exceed (1) such Lender's Commitment
Percentage of the Available Canadian Subcommitment minus (2) such Lender's
outstanding Loans and (ii) for all Lenders shall not exceed the Available
Canadian Subcommitment, as then in effect, minus the aggregate amount of all
outstanding Loans.

     (c) DELIVERY OF BANKERS' ACCEPTANCES. Upon execution of this Agreement, the
Company shall deliver to each Lender bills of exchange, in the form for Bankers'
Acceptances of such Lender, executed in blank in sufficient quantity and
thereafter shall, from time to time upon request of the Administrative Agent,
deliver to the Lenders further quantities of such bills of exchange (on the
Administrative Agent's forms) so executed, and the Lenders shall hold such bills
of exchange in safekeeping. The present form of Bankers' Acceptances of each
Lender is set out in Exhibit B.

     (d) SAFEKEEPING OF BANKERS' ACCEPTANCES. The bills of exchange so executed
in blank and delivered to each Lender shall be held in safekeeping in the vault
of one of each such Lender's branches. The standard of care that each Lender
shall maintain in its safekeeping of such bills of exchange shall be at least as
high as that maintained by such Lender in the safekeeping of its own securities.
Each Lender shall indemnify and hold and save harmless the Company from loss or
damage resulting from the failure of such Lender to maintain such standard of
care.

     (e) LOANS UNDER PRIOR CREDIT AGREEMENT.  On the Effective Date:

         (i)   the Company shall pay all accrued and unpaid commitment fees
     outstanding under the Prior Credit Agreement for the account of each
     "Lender" under the Prior Credit Agreement;

         (ii)  each "Base Rate Loan" and each "Bankers' Acceptance" under the
     Prior Credit Agreement shall be deemed to be repaid with the proceeds of a
     new Base Rate Loan under this Agreement; and

                                       6
<PAGE>
 
         (iii) the Prior Credit Agreement and the commitments thereunder shall
     be superseded by this Agreement and shall be amended and restated as set
     forth herein.

     SECTION 2.02  BORROWINGS, RENEWALS, CONVERSIONS, AND ISSUANCES.

     (a) BORROWINGS. The Company shall give the Administrative Agent (which
shall promptly notify the Lenders) advance notice as hereinafter provided of
each Borrowing, renewal, and conversion, which shall specify the aggregate
amount of such Borrowing, and the date (which shall be a Business Day) of the
Borrowing to be borrowed, renewed or converted, all of which must be reasonably
acceptable to the Administrative Agent, and in the case of Bankers' Acceptances,
all details of the proposed issue, specifying the aggregate amount of Bankers'
Acceptances to be accepted and purchased by the Lenders and the duration of the
Interest Period therefor. Promptly following such notice the Administrative
Agent will notify the Company and the Lenders of the Discount Rate for the
specified Acceptance Date.

     (b) MINIMUM AMOUNTS. All Base Rate Loans (as part of the same Borrowing)
shall be in aggregate amounts among all Lenders of at least $1,000,000 (or whole
multiples thereof) or the remaining unused portion of the Commitments. All
Bankers' Acceptances (as part of the same Borrowing) shall be in aggregate
amounts among all Lenders of not less than $1,000,000 and in whole multiples of
$100,000.

     (c) NOTICES, ETC. FOR LOANS. All Borrowings, renewals and conversions shall
require advance written notice from the Company to the Administrative Agent, in
the form of Exhibit D, or such other form as may be accepted by the
Administrative Agent from time to time, which in each case shall be irrevocable
and effective only upon receipt by the Administrative Agent and shall be
received by the Administrative Agent not later than (i) in the case of a Base
Rate Loan, 11:00 a.m. Toronto time on the date of such Borrowing, renewal or
conversion; and (ii) in the case of Bankers' Acceptances, 12:00 noon Toronto
time on a day that is not less than one (1) Business Day prior to the date of
such Borrowing, renewal or conversion. Not later than 12:00 noon Toronto time on
the date specified for each Borrowing hereunder or each request for the
acceptance and purchase of a Bankers' Acceptance, each Lender shall make
available the amount of the Loan or the Available Proceeds of the Bankers'
Acceptance to be made by such Lender on such date to the Administrative Agent,
at account number 219274 maintained by the Administrative Agent at The Royal
Bank of Canada, Correspondent Banking Division, Toronto, Canada, in immediately
available funds for the account of the Company. The amounts so received by the
Administrative Agent shall, subject to the terms and conditions of this
Agreement, be made available to the Company by depositing the same, in
immediately available funds, in an account of the Company designated by the
Company.

     (d) REPLACEMENT/RENEWAL ACCEPTANCES. Subject to the terms of this
Agreement, the Company may elect to cause a new replacement Bankers' Acceptance
to be issued, accepted and purchased to replace all or any part of any Bankers'
Acceptance at the maturity thereof by giving one (1) Business Day's advance
notice to the Administrative Agent of such election, specifying the amount of
such new Bankers' Acceptance and the Interest Period therefor. In the absence of
such a timely and proper election, the Company shall be deemed to have elected
to convert such Bankers' Acceptance to a Base Rate Loan as provided in 
Section 2.12(b). All or any part of any Bankers' Acceptance may be renewed as 
provided herein, provided that (i) any renewal Bankers'

                                       7
<PAGE>
 
Acceptance shall meet all requirements for Bankers' Acceptances hereunder, (ii)
no Default shall have occurred and be continuing and (iii) the Company shall
have paid to the Administrative Agent for the account of Lenders an amount equal
to the difference between the amount due on the maturing Bankers' Acceptance and
the Available Proceeds of the new Bankers' Acceptance. If a Default shall have
occurred and be continuing, each Bankers' Acceptance shall be converted to a
Base Rate Loan on the last day of the Interest Period applicable thereto unless
the Termination Date has occurred in which event all sums due thereon shall be
immediately due and payable.

     (e) CONVERSION OPTIONS. The Company may elect to convert any Bankers'
Acceptance on the last day of the then current Interest Period relating thereto
to a Base Rate Loan by giving advance notice to the Administrative Agent of such
election. If no Default shall have occurred and be continuing, subject to the
terms of this Agreement, the Company may elect to convert all or any part of a
Base Rate Loan at any time and from time to time to a Bankers' Acceptance by
giving one (1) Business Day's advance notice to the Administrative Agent of such
election; provided that any conversion of any Base Rate Loan into a Bankers'
Acceptance shall be in an amount not less than $1,000,000 in the aggregate for
all Lenders and in whole multiples of $100,000.

     (f) PRO RATA TREATMENT. Unless otherwise agreed among the Lenders, all
Loans shall be made by all Lenders pro rata relative to their respective
Commitment Percentage and the aggregate amount of all Bankers' Acceptances
issued hereunder shall be issued pro rata by all Lenders relative to their
respective Commitment Percentage, rounded, upwards or downwards, as the case may
be, to the nearest $100,000.

     SECTION 2.03  CHANGES OF COMMITMENTS.

     (a) EXTENSION OF TERMINATION DATE. All of the Lenders and the U.S. Lenders
may extend the Termination Date as set forth in Section 2.03(a) of the U.S.
Credit Agreement, which section is hereby incorporated by reference into this
Agreement and made a part of this Agreement to the same extent as if set forth
in full herein, except that for purposes hereof, references therein to "Lenders"
and "Canadian Lenders" shall be deemed to be references to "U.S. Lenders" and
"Lenders," respectively, and, as appropriate in the context, other corresponding
changes shall be made, mutatis mutandis.

     (b) OPTIONAL REDUCTION. The Company shall have the right to terminate or to
reduce the amount of the Commitments at any time or from time to time upon not
less than one (1) Business Day's prior notice to the Administrative Agent (which
shall promptly notify the Lenders) of each such termination or reduction, which
notice shall specify the effective date thereof and the amount of any such
reduction (which shall not be less than $5,000,000, or any whole multiple of
$1,000,000 in excess thereof), and shall be irrevocable and effective only upon
receipt by the Administrative Agent.

     (c) REINSTATEMENT. Other than increases pursuant to Section 2.09, the
Commitments once terminated or reduced may not be reinstated. The amount of the
Available Canadian Subcommitment may increase or decrease from time to time in
accordance with the terms of this Agreement, including but not limited to,
Section 2.09.

                                       8
<PAGE>
 
     SECTION 2.04  COMMITMENT FEE AND OTHER FEES. The Company shall pay to the
Administrative Agent for the account of the Lenders an aggregate commitment fee
on the daily average unused amount of such Lender's Available Canadian
Subcommitment for the period from and including the Effective Date of this
Agreement to and including the Termination Date, at a rate per annum equal to
the Facility Fee Rate.  The commitment fee shall be payable in arrears on each
Quarterly Date and on the Termination Date.

     SECTION 2.05  LENDING OFFICES. The Loans made and Bankers' Acceptances
accepted and purchased by each Lender shall be made and maintained at such
Lender's Applicable Lending Office, which shall be located in Canada.

     SECTION 2.06  SEVERAL OBLIGATIONS. The failure of any Lender to make any
funds available in connection with any Borrowing to be funded by such Lender on
the date specified therefor shall not relieve any other Lender of its obligation
to provide such funds on such date, but neither the Administrative Agent nor any
Lender shall be responsible for the failure of any other Lender to provide funds
to be provided by such other Lender.

     SECTION 2.07  NOTES.

     (a) SINGLE PROMISSORY NOTE. The Loans made by each Lender shall be
evidenced by a single promissory note of the Company in substantially the form
of Exhibit A hereto, dated as of the Effective Date or such later date upon a
permitted assignment of all or any portion of such Note, payable to the order of
such Lender in a principal amount equal to the maximum amount of its Commitment
as originally in effect and otherwise duly completed. The date, amount, interest
rate and maturity date of each Loan made by each Lender, and all payments made
on account of the principal thereof, shall be recorded by such Lender on its
books and, prior to any transfer of the Note held by it, endorsed by such Lender
on the schedule attached to such Note or any continuation thereof.

     (b) NO RIGHT TO SUBDIVIDE. No Lender shall be entitled to have its Note
subdivided, by exchange for promissory notes of lesser denominations or
otherwise, except in connection with a permitted assignment of all or any
portion of such Lender's Commitment, Loans and Note pursuant to 
Section 12.03(b).

     SECTION 2.08  PREPAYMENTS.

     (a) OPTIONAL PREPAYMENTS. The Company may prepay any Loans or cash
collateralize Bankers' Acceptances on any Business Day upon notice to the
Administrative Agent (which shall promptly notify the Lenders), which notice
shall be given by the Company not later than 12:00 noon Toronto time on such
Business Day, shall specify the amount of the prepayment (which shall be not
less than $1,000,000 or the remaining balance of Base Rate Loans outstanding, if
less) and shall be irrevocable and effective only upon receipt by the
Administrative Agent, provided that interest on the principal prepaid on any
Loan, accrued to the prepayment date, shall be paid on the prepayment date. Any
prepayment of any Bankers' Acceptances shall be subject to the provisions of
Sections 2.08(d), 2.08(e) and 5.05.

     (b) MANDATORY PREPAYMENT UPON REDUCTION OF COMMITMENT. If, after giving
effect to any termination or reduction of the Commitments pursuant to 
Section 2.03, the sum of

                                       9
<PAGE>
 
the out-standing aggregate principal amount of the Loans and the Acceptance
Exposure exceeds the aggregate amount of the Commitments, then the Company shall
on the date of such termination or reduction pay or prepay the amount of such
excess amount for application first, towards reduction of the outstanding
principal balance of the Notes and then, if necessary, by cash collateralizing
(or prepaying if acceptable to the holder thereof) Bankers' Acceptances, if any,
then outstanding subject to the provisions of Section 2.08(d). The Company shall
on the date of such termination or reduction also pay any amounts payable
pursuant to Section 5.05 in connection therewith.

     (c) NO PENALTY OR PREMIUMS. Subject to compensation requirements of
Section 5.05 hereof, all prepayments shall be without premium or penalty.

     (d) PRO RATA TREATMENT. Without duplication of Section 5.05, but subject to
Section 2.08(e), any prepayment of Bankers' Acceptances shall be in an amount
equal to the full face amount of any Bankers' Acceptance so prepaid (less any
unearned Discount Amount and Stamping Fee), and be pro rata among all Lenders
relative to their respective Commitments.

     (e) BANKERS' ACCEPTANCES. A Bankers' Acceptance may only be repaid on the
last day of its Interest Period unless consented to by the holder thereof. In
lieu of prepayment of a Bankers' Acceptance, the Company may cash collateralize
a Bankers' Acceptance by delivery to the Administrative Agent for distribution
to each Lender such discounted amount in respect of such Bankers' Acceptance as
the Administrative Agent, acting reasonably, advises the Lender will enable the
Lender, based upon the rate of return the Lender will be able to earn on the
funds so received, to pay the full face amount of such Bankers' Acceptance on
the last day of such Interest Period.

     SECTION 2.09  AVAILABLE CANADIAN SUBCOMMITMENT.

     (a) ALLOCATED CANADIAN BORROWING BASE. The Allocated Canadian Borrowing
Base in effect from time to time shall represent the maximum amount of Loans and
Bankers' Acceptances that the Lenders will loan or accept to or for the Company
at any one time prior to the Termination Date. On the Effective Date, the
Allocated Canadian Borrowing Base shall be U.S. $7,000,000.

     (b) REALLOCATION. The Company, the Administrative Agent and the Lenders
agree that OEI-Delaware shall have the right to request that the Allocated
Canadian Borrowing Base be increased or decreased, and the Allocated U.S.
Borrowing Base be decreased or increased, respectively, in a corresponding
amount, all as more particularly set forth in Section 2.09(a) of the U.S. Credit
Agreement, which provisions are hereby incorporated by reference into this
Agreement and made a part of this Agreement to the same extent as if set forth
in full herein, except that for purposes hereof, references therein to "Lenders"
and "Canadian Lenders" shall be deemed to be references to "U.S. Lenders" and
"Lenders," respectively, and, as appropriate in the context, other corresponding
changes shall be made, mutatis mutandis.

     (c) NO CHANGE TO GLOBAL COMMITMENT. The Company, the Administrative Agent
and the Lenders agree that reallocations of the Allocated U. S. Borrowing Base
and Allocated

                                       10
<PAGE>
 
Canadian Borrowing Base shall not, without the prior written agreement of all
the U.S. Lenders, the Lenders and OEI-Delaware, affect the Global Commitment
Percentage.

     SECTION 2.10  ACCEPTANCE DATE PROCEDURE. On the Acceptance Date, the
following provisions shall apply:

     (a) On or before 10:30 a.m. Toronto time on the Acceptance Date, the
Administrative Agent shall promptly determine the Discount Rate and notify each
Lender as to:

         (i)   the Discount Rate;

         (ii)  the face amount of the Bankers' Acceptances to be purchased by
     such Lender on such Acceptance Date;

         (iii) the amount of the Stamping Fee applicable to those Bankers'
     Acceptances to be accepted and purchased by such Lender on such Acceptance
     Date, such Lender being authorized by the Company to collect the Discount
     Amount and the Stamping Fee out of the proceeds of the Bankers' Acceptances
     upon the Lender's acceptance and purchase thereof;

         (iv)  the Available Proceeds by subtracting the Discount Amount and the
     Stamping Fee mentioned in subsection (iii) from the face amount mentioned
     in subsection (ii).

     (b) As provided in Section 2.02(c), not later than 2:00 p.m. Toronto time
that same day, each Lender shall make available to the Administrative Agent its
Available Proceeds and the Administrative Agent shall make the Available
Proceeds available to the Company.

     SECTION 2.11  PURCHASE OF BANKERS' ACCEPTANCES. The Lenders shall, on the
Acceptance Date, accept the Bankers' Acceptances, by inserting the appropriate
face amount, Acceptance Date and maturity date thereof in accordance with the
Company's notice relating thereto and affixing their acceptance stamps thereto,
and shall purchase same as provided in Section 2.10.

     SECTION 2.12  PAYMENT OF BANKERS' ACCEPTANCES. The Bankers' Acceptances
shall be payable in accordance with the following provisions:

     (a) If such Bankers' Acceptances are held by or presented to the Accepting
Lender or the Administrative Agent, the Company shall pay to the Administrative
Agent for the account of each Lender an amount equal to the face amount of the
Bankers' Acceptances of such Lender on their respective maturity dates. In the
event that any Bankers' Acceptance is presented to the Company, rather than the
Accepting Lender thereof, for payment on its respective maturity date and the
Company shall have made payments to the holders thereof, then the Company shall
give notice to the Administrative Agent to such effect together with the
original canceled Bankers' Acceptance and the Administrative Agent shall
promptly notify the Lenders.

     (b) In the event the Company fails to notify the Administrative Agent in
writing, not later than 12:00 Noon, one (1) Business Day prior to any maturity
date of a Bankers'

                                       11
<PAGE>
 
Acceptance, that the Company intends to pay with its own funds the amount of the
Bankers' Acceptances due on such maturity date, the Company shall be deemed, for
all purposes, to have given the Administrative Agent notice to convert the
amount of such Bankers' Acceptances into a Base Rate Loan and the provisions of
Section 2.02(f) shall apply, except save that:

         (i)   such maturity date shall be considered to be the borrowing date
     of such Base Rate Loan;

         (ii)  the proceeds of such Base Rate Loan shall be used to pay the
     amount of the Bankers' Acceptance due on such maturity date; and

         (iii) on such maturity date, each Lender, instead of making its funds
     available to the Administrative Agent to fund such Base Rate Loan, shall
     first directly apply its pro rata share of such Loan in payment of its pro
     rata share in the amount of its Bankers' Acceptances due on such date.

               ARTICLE III:  PAYMENTS OF PRINCIPAL AND INTEREST

     SECTION 3.01  REPAYMENT OF LOANS. The Company will pay on the Termination
Date to the Administrative Agent for the account of each Lender the then-
outstanding principal amount of each Loan made by such Lender and the amount of
the Acceptance Exposure.

     SECTION 3.02  INTEREST.

     (a) The Company will pay to the Administrative Agent for the account of
each Lender interest on the unpaid principal amount of each Loan made by such
Lender for the period commencing on the date of such Loan to but excluding the
date such Loan shall be paid in full, at the Base Rate (as in effect from time
to time) plus the Applicable Margin for such Loan, but in no event to exceed the
Highest Lawful Rate.

     (b) Accrued interest on each Loan shall be payable quarterly on each
Quarterly Date, except that interest payable after maturity shall be payable
from time to time on demand.

     (c) Promptly after the determination of any interest rate provided for
herein or any change therein, the Administrative Agent shall notify the Lenders
to which such interest is payable and the Company.

         ARTICLE IV:  PAYMENTS; PRO RATA TREATMENT; COMPUTATIONS; ETC.

SECTION 4.01  PAYMENTS. Except to the extent otherwise provided herein, all
payments of principal, interest and other amounts to be made by the Company
under this Agreement, the Notes and the Bankers' Acceptances shall be made in
Dollars, in immediately available funds, to the Administrative Agent at transit
#09591, account number 219-2474-4 maintained by the Administrative Agent at
Royal Bank of Canada, Correspondent Banking Division, Toronto Canada, not later
than 12:00 noon Toronto Time on the date on which such payments shall become due
(each such payment made after such time on such due date to be deemed to have
been made on the next succeeding Business Day). The Company shall, subject to
Section 4.02, at the time of making each payment under this Agreement or any
Note or Bankers' Acceptance,

                                       12
<PAGE>
 
specify to the Administrative Agent the Loans, Bankers' Acceptances or other
amounts payable by the Company hereunder to which such payment is to be applied
(and in the event that it fails to so specify, and such day is not a Quarterly
Date or other day on which a payment of either interest or principal is due,
then such payments shall be applied in the following order: first, to interest
accrued on Loans, second, any excess to reduce the aggregate principal amount
then outstanding on the Loans and, third, any excess to Bankers' Acceptances;
provided, however, that if an Event of Default has occurred and is continuing,
the Administrative Agent may distribute such payment to the Lenders in such
manner as it or the Required Lenders may determine to be appropriate, subject to
Section 4.02). Each payment received by the Administrative Agent under this
Agreement or any Note or Bankers' Acceptance for the account of a Lender shall
be paid promptly to such Lender, in immediately available funds, for account of
such Lender's Applicable Lending Office for the Loan or Bankers' Acceptances in
respect of which such payment is made. If the due date of any payment under this
Agreement or any Loan Document would otherwise fall on a day which is not a
Business Day such date shall be extended to the next succeeding Business Day and
interest shall be payable for any amount so extended for the period of such
extension.

     SECTION 4.02  PRO RATA TREATMENT. Except to the extent agreed among the
Lenders or otherwise provided herein: (a) each Borrowing from the Lenders under
Section 2.01 shall be made from the Lenders, each payment of commitment fee or
other fees under Section 2.04 shall be made for account of the Lenders, and each
termination or reduction of the amount of the Commitments under Section 2.03
shall be applied to the Commitments of the Lenders, pro rata according to their
respective Commitment Percentages, (b) each payment of Bankers' Acceptances or
principal of Loans by the Company shall be made for account of the Lenders pro
rata in accordance with the aggregate unpaid principal amount of Loans and face
amount of Bankers' Acceptances held or purchased by the Lenders, and (c) each
payment of interest on Loans by the Company shall be made for account of the
Lenders pro rata in accordance with the amounts of interest due and payable on
such Loans to the respective Lenders.

     SECTION 4.03  COMPUTATIONS. Interest on Loans and fees shall be computed on
the basis of a year of 365 or 366 days, as the case may be, and actual days
elapsed (including the first day but excluding the last day) occurring in the
period for which payable. The Applicable Margin for determining the Stamping Fee
for Bankers' Acceptances shall be computed on the basis of a year of 365 days.
Any rates of interest not expressed in this Agreement on the basis of a 365 day
or 366 day year are the equivalent, expressed on a calendar year basis, of the
same rate of interest multiplied by a fraction, the numerator of which is the
actual number of days in the applicable calendar year and the denominator of
which is the number of days on which interest is expressed to be based.

     SECTION 4.04  NON-RECEIPT OF FUNDS BY THE ADMINISTRATIVE AGENT. Unless the
Administrative Agent shall have been notified by a Lender or the Company prior
to the date on which a payment is scheduled to be made to the Administrative
Agent of (in the case of a Lender) the proceeds of a Borrowing to be made by it
hereunder or (in the case of the Company) a payment to the Administrative Agent
for account of one or more of the Lenders hereunder (such payment being herein
called a "Required Payment"), which notice shall be effective upon receipt, that
it does not intend to make the Required Payment to the Administrative Agent, the
Administrative Agent may assume that the Required Payment has been made and may,
in

                                       13
<PAGE>
 
reliance upon such assumption (but shall not be required to), make the amount
thereof available to the intended recipient(s) on such date and, if such Lender
or the Company (as the case may be) has not in fact made the Required Payment to
the Administrative Agent, the recipient(s) of such payment shall, on demand,
repay to the Administrative Agent the amount so made available together with
interest thereon in respect of each day during the period commencing on the date
such amount was so made available by the Administrative Agent until the date the
Administrative Agent recovers such amount at a rate per annum equal to the Base
Rate for such day, but in no event to exceed the Highest Lawful Rate.

     SECTION 4.05  SHARING OF PAYMENTS, ETC.

     (a) The Company agrees that, in addition to (and without limitation of) any
right of set-off, bankers' lien or counterclaim a Lender may otherwise have,
each Lender shall be entitled (after consultation with the Administrative
Agent), at its option, during the existence of an Event of Default, to offset
balances held by it for account of the Company at any of its offices, in Dollars
or in any other currency, against any principal of or interest on any of such
Lender's Loans or Bankers' Acceptances, or any other amount payable to such
Lender hereunder which is not paid when due (regardless of whether such balances
are then due to the Company), in which case such Lender shall promptly notify
the Company and the Administrative Agent thereof, provided that such Lender's
failure to give such notice shall not affect the validity thereof.

     (b) If any Lender shall obtain payment of any principal of or interest on
any Loan or reimbursement on any Bankers' Acceptance made available to the
Company under this Agreement through the exercise of any right of set-off,
banker's lien or counterclaim or similar right or otherwise, and, as a result of
such payment, such Lender shall have received a greater percentage of the
principal or interest or reimbursement obligation then due hereunder by the
Company to such Lender than the percentage received by any other Lenders, such
Lender shall promptly purchase from such other Lenders participations in (or, if
and to the extent specified by such Lender, direct interests in) the Loans or
Bankers' Acceptances made by such other Lenders (or in interest due thereon, as
the case may be), and make such other adjustments from time to time as shall be
equitable, to the end that all the Lenders shall share the benefit of such
excess payment (net of any expenses which may be incurred by such Lender in
obtaining or preserving such excess payment) pro rata in accordance with the
aggregate unpaid principal and interest on the Loans and reimbursement
obligations on the Bankers' Acceptances held or accepted by each of the Lenders.
To such end, all the Lenders shall make appropriate adjustments among themselves
(by the resale of participations sold or other-wise) if such payment is
rescinded or must otherwise be restored. The Company agrees that any Lender so
purchasing a participation (or direct interest) in the Loans or Bankers'
Acceptances made by other Lenders (or in interest due thereon, as the case may
be) may exercise all rights of set-off, bankers' lien, counter-claim or similar
rights with respect to such participation as fully as if such Lender were a
direct holder of Loans or acceptor of Bankers' Acceptances, as the case may be,
in the amount of such participation. Nothing contained herein shall require any
Lender to exercise any such right or shall affect the right of any Lender to
exercise, and retain the benefits of exercising, any such right with respect to
any other indebtedness or obligation of the Company. If under any applicable
bankruptcy, insolvency or other similar law, any Lender receives a secured claim
in lieu of a set-off to which this Section 4.05 applies, such Lender shall, to
the extent practicable, exercise its rights in respect of such secured claim in
a manner consistent with the rights of the

                                       14
<PAGE>
 
Lenders entitled under this Section 4.05 to share the benefits of any recovery
on such secured claim.

     SECTION 4.06  INTEREST ACT (CANADA).

     (a) For purposes of the Interest Act (Canada), (i) whenever any interest or
fee under this Agreement is calculated using a rate based on a year of 360 days
or 365 days, such rate determined pursuant to such calculation, when expressed
as an annual rate, is equivalent to (x) the applicable rate based on a year of
360 days or 365 days, as the case may be, (y) multiplied by the actual number of
days in the calendar year in which the period for which such interest or fee is
payable (or compounded) ends, and (z) divided by 360 or 365 as the case may be.

     (b) The principle of deemed reinvestment of interest shall not apply to any
interest calculation under this Agreement, and the rates of interest stipulated
in this Agreement are intended to be nominal rates and not effective rates or
yields.

     (c) To the extent permitted by law, section 6 of the Judgment Interest Act
(Alberta) shall not apply to this Agreement and is hereby expressly waived by
the Company.

                  ARTICLE V:  YIELD PROTECTION AND ILLEGALITY

     SECTION 5.01  ADDITIONAL COSTS.

     (a) REGULATORY CHANGE. The Company shall pay directly to each Lender from
time to time such amounts as such Lender may determine to be necessary to
compensate it for any increased costs incurred by the Lender which such Lender
determines are attributable to its making or maintaining any Loans or Bankers'
Acceptances or its obligation to make any Loans or Bankers' Acceptances
hereunder, or any reduction in any amount receivable by such Lender hereunder in
respect of any of such Loans or Bankers' Acceptances (such increases in costs
and reductions in amounts receivable being herein called "Additional Costs"),
resulting from any Regulatory Change which: (i) changes the basis of taxation of
any amounts payable to such Lender under this Agreement in respect of any of
such Loans or Bankers' Acceptances (other than franchise taxes, taxes on capital
and/or gross receipts or taxes imposed on the overall net income of such Lender
or of its Applicable Lending Office for any of such Loans or Bankers'
Acceptances by the jurisdiction in which such Lender has its principal office or
such Applicable Lending Office ("Excluded Taxes")); or (ii) imposes or modifies
any reserve, special deposit, minimum capital, capital ratio or similar
requirements relating to any extensions of credit or other assets of, or any
deposits with or other liabilities of, such Lender, or any Commitment of such
Lender; or (iii) imposes any other condition affecting this Agreement or its
Loans or Bankers' Acceptances (or any of such extensions of credit or
liabilities) or Commitment. If any Lender requests compensation from the Company
under this Section 5.01, the Company may, by notice to such Lender (with a copy
to the Administrative Agent), suspend the obligation of such Lender to make
additional Loans or accept and purchase additional Bankers' Acceptances of the
type with respect to which such compensation is requested until the Regulatory
Change giving rise to such request ceases to be in effect (in which case the
provisions of Section 5.04 shall be applicable).

                                       15
<PAGE>
 
     (b) CAPITAL ADEQUACY. Without limiting the effect of the foregoing
provisions of this Section 5.01 (but without duplication), the Company shall pay
directly to each Lender from time to time on request such amounts as such Lender
may determine to be necessary to compensate such Lender for any costs which it
determines are attributable to the maintenance by such Lender (or any Applicable
Lending Office), pursuant to any law or regulation or any interpretation,
directive or request (whether or not having the force of law) of any court or
governmental or monetary authority following any Regulatory Change, of capital
in respect of its Commitment, such compensation to include, without limitation,
an amount equal to any reduction of the rate of return on assets or equity of
such Lender (or any Applicable Lending Office) to a level below that which such
Lender (or any Applicable Lending Office) could have achieved but for such law,
regulation, interpretation, directive or request.

     SECTION 5.02  ILLEGALITY. If the introduction of or any change in,
applicable law, regulation, treaty or official directive, or regulatory
requirement or the interpretation or application thereof by any court or by any
governmental authority charged with the administration thereof, makes it
unlawful, or prohibited for any Lender (in its sole opinion) to accept,
purchase, trade or hold Bankers' Acceptances, such Lender may, by written notice
to the Administrative Agent, which notice shall be promptly communicated by the
Administrative Agent to the Company, terminate its obligations to accept,
purchase, trade or hold Bankers' Acceptances and the Company shall repay or cash
collateralize, as the case may be, such Bankers' Acceptances then outstanding
forthwith together with any payments required under Section 5.05, or at the end
of such period as such Lender in its discretion agrees, (it being understood and
agreed that the Lender shall use its best efforts to permit such prepayment to
occur on the maturity date of Bankers' Acceptances, if this is legally
permissible) together with all additional amounts as may be applicable to the
date of payment and may reborrow, subject to the terms hereof, any amount which
has been prepaid pursuant to this Section 5.02, by way of one of the remaining
legal basis of Borrowings available under this Agreement, as provided in
Section 5.04.

     SECTION 5.03  ADDITIONAL COST IN RESPECT OF TAX.

     (a) PAYMENTS FREE AND CLEAR. Each payment to be made by the Company
hereunder or in connection herewith to any Lender or any other Person shall be
made free and clear of and without deduction for or on account of any Tax unless
the Company is required to make such payment subject to the deduction or
withholding of Tax, in which case (except for Excluded Taxes) the sum payable by
the Company in respect of which such deduction or withholding is required to be
made shall be increased to the extent necessary to ensure that, after the making
of such deduction or withholding, such other Person receives and retains (free
from any liability in respect of any such deduction or withholding) a net sum
equal to the sum which it would have received and so retained had not such
deduction or withholding been made or required to be made.

     (b) OBLIGATION TO INDEMNIFY. If (i) any Lender or the Administrative Agent,
on behalf of such Lender or on its own behalf, is required by law to make any
payment on account of any Tax (except for Excluded Taxes) on or in relation to
any sum received or receivable hereunder by such Lender or the Administrative

                                       16
<PAGE>
 
Agent, or (ii) any liability in respect of any such payment is asserted,
imposed, levied or assessed against such Lender or the Administrative Agent (as
the case may be) against such payment or liability, the Company shall promptly
pay to the Administrative Agent or such Lender, as the case may be, any
additional amounts necessary to compensate the Administrative Agent or such
Lender for such payment together with any interest, penalties and expenses
payable or incurred in connection therewith. If the Administrative Agent or a
Lender has paid over on account of Tax (other than Excluded Taxes) an amount
paid to the Administrative Agent or such Lender by the Company pursuant to the
foregoing indemnification and the amount so paid over is subsequently refunded
to the Administrative Agent or such Lender, in whole or in part, the
Administrative Agent or such Lender, as appropriate, shall promptly remit such
amount refunded to the Company.

     (c) NOTICE OF CHANGES; PROOF OF PAYMENT. If at any time the Company is
required by law to make any deduction or withholding from any sum payable by it
hereunder or in connection herewith (or if thereafter there is any change in the
rates at which or the manner in which such deductions or withholdings are
calculated) the Company shall promptly notify the Administrative Agent thereof.
If the Company makes any payment hereunder or in connection herewith in respect
of which it is required by law to make any deduction or withholding it shall pay
the full amount to be deducted or withheld to the relevant taxation or other
authority within the time allowed for such payment under applicable law and
shall deliver to the Administrative Agent within thirty (30) days after it has
made such payment to the applicable authority (i) a receipt issued by such
authority or (ii) other evidence reasonably satisfactory to the Administrative
Agent evidencing the payment to such authority of all amounts so required to be
deducted or withheld from such payment.

     SECTION 5.04  BASE RATE LOANS PURSUANT TO SECTIONS 5.01 AND 5.02.  If the
obligation of any Lender to accept and purchase Bankers' Acceptances shall be
suspended pursuant to Section 5.01 or 5.02 ("Affected Loans"), all Affected
Loans which would otherwise be made available by such Lender shall be made
instead as Base Rate Loans (and, if an event referred to in Section 5.01(a) or
Section 5.02 has occurred and such Lender so requests by notice to the Company
with a copy to the Administrative Agent, all Affected Loans of such Lender then
outstanding shall be automatically converted into Base Rate Loans, subject to
Section 5.05, on the date specified by such Lender in such notice) and, to the
extent that Affected Loans are so made as (or converted into) Base Rate Loans,
all payments which would otherwise be applied to such Lender's Affected Loans
shall be applied instead to its Base Rate Loans.

     SECTION 5.05  COMPENSATION. The Company shall pay to the Administrative
Agent for account of each Lender, upon the request of such Lender through the
Administrative Agent, such amount or amounts as shall be sufficient (in the
reasonable opinion of such Lender) to compensate it for any loss, cost or
expense which such Lender determines are attributable to:

     (a) any payment or conversion of a Bankers' Acceptance for any reason
(including, without limitation, the acceleration of the Loans pursuant to
Section 10.01) on a date other than the last day of the Interest Period for such
Bankers' Acceptance; or

     (b) any failure by the Company for any reason (including but not limited
to, the failure of any of the conditions precedent specified in Article VI to be
satisfied, but excluding failures arising out of the negligence, gross
negligence or willful misconduct of a Lender or the

                                       17
<PAGE>
 
Administrative Agent) to issue a Bankers' Acceptance to such Lender on the date
for such issuance specified in the relevant notice of Borrowing given pursuant
to Section 2.02.

     SECTION 5.06  AVOIDANCE OF TAXES AND ADDITIONAL COSTS.

     (a) CHANGE APPLICABLE FUNDING OFFICE. If a Lender makes any claim under
Section 5.01 or Section 5.03 in respect of Additional Costs or Taxes, such
Lender shall be obligated to use reasonable efforts to designate a different
Applicable Lending Office for the Commitment or the Loans or the Bankers
Acceptances of such Lender affected by such event if such designation will avoid
the need for, or reduce the amount of, such compensation or the imposition of
any Taxes and will not, in the sole opinion of such Lender, be disadvantageous
to such Lender; provided that such Lender shall have no obligation to so
designate an Applicable Lending Office located in Canada.

     (b) REPLACEMENT. If any Lender claims (i) payment of Additional Costs, (ii)
the inability to make or maintain the Bankers Acceptances pursuant to 
Section 5.01 or 5.02 (when such inability is not then being claimed by
substantially all of the Lenders) or (iii) payment of any Taxes pursuant to
Section 5.03, then the Company shall have the right, upon payment of such
requested Additional Costs or Taxes to (i) prepay the Loans made by such Lender,
cash collateralize the Bankers Acceptances then outstanding which have been
discounted by such Lender, and terminate the Commitment of such Lender on a non
pro rata basis or (ii) subject to the approval of the Administrative Agent (such
approval not to be unreasonably withheld or delayed), find one or more Persons
willing to assume the Loans, Commitment and other obligations of such Lender and
replace such Lender pursuant to an Assignment and Acceptance. Any such
assumption shall be effected pursuant to Section 12.03(b). The Company shall
not, however, be entitled to replace any Lender if an event which with notice or
lapse of time, or both, would constitute a Default or an Event of Default exists
at the time.

     SECTION 5.07  LIMITATION ON RIGHT TO COMPENSATION. Any demand for
compensation pursuant to Article V (other than Section 5.03) must be made on or
before six (6) months after the Lender incurs the expense, cost or economic loss
referred to or such Lender shall be deemed to have waived the right to such
compensation. Any demand for compensation pursuant to Section 5.03 must be made
on or before twelve (12) months after the Lender incurs the expense, cost or
economic loss referred to or such Lender shall be deemed to have waived the
right to such compensation.

     SECTION 5.08  COMPENSATION PROCEDURE. Each Lender will notify the Company
of any event occurring after the date of this Agreement which will entitle such
Lender to compensation pursuant to this Article V as promptly as practicable
after it obtains knowledge thereof and determines to request such compensation,
and will furnish the Company with a certificate setting forth the basis and
amount of each request by such Lender for compensation under this Article V.
Such certificate shall also include (i) calculations in reasonable detail
computing such claim, and (ii) a statement from such Lender that it is asserting
its right for indemnity or compensation not solely with respect to the
Indebtedness outstanding under this Agreement, but is generally making such
claims with respect to similar borrowers in connection with transactions similar
to the one contemplated in this Agreement. Determinations and allocations by any
Lender for purposes of this Article V of the effect of any Regulatory Change
pursuant to Section 5.01(a), or

                                       18
<PAGE>
 
of the effect of capital maintained pursuant to Section 5.01(b), on its costs or
rate of return of accepting and purchasing Bankers' Acceptances or maintaining
Loans or its obligation to make Loans or accept and purchase Bankers'
Acceptances, or on amounts receivable by it in respect of Loans or Bankers'
Acceptances, and of the additional amounts required to compensate such Lender
under this Article V, shall be conclusive, provided that such determinations and
allocations are made on a reasonable basis.

                       ARTICLE VI:  CONDITIONS PRECEDENT

     SECTION 6.01  EFFECTIVENESS. The effectiveness of this amendment and
restatement is subject to the receipt by the Administrative Agent of the
following documents and satisfaction of the other conditions provided in this
Section 6.01, each of which shall be satisfactory to the Administrative Agent in
form and substance:

     (a) A Certificate of the Secretary or Assistant Secretary of the Company
setting forth (i) that the resolutions of its board of directors attached to
such certificate are in full force and effect with respect to the authorization
of the execution, delivery and performance of the obligations contained in the
Notes, this Agreement and the other Loan Documents to which it is a party, (ii)
that the officers of the Company specified in such Secretary's Certificate are
authorized to sign this Agreement, the Notes, and the other Loan Documents to
which it is a party and who, until replaced by another officer or officers duly
authorized for that purpose, will act as the Company's respective representative
for the purposes of signing documents and giving notices and other
communications in connection with this Agreement and the other Loan Documents to
which it is a party and the transactions contemplated hereby and thereby, (iii)
specimen signatures of the officers so authorized, and (iv) that attached to
such certificate are true and complete copies of the articles and memorandum of
the Company. The Administrative Agent and the Lenders may conclusively rely on
such certificate until the Administrative Agent receives notice in writing from
the Company to the contrary.

     (b) A certificate of the Secretary or Assistant Secretary of each Guarantor
setting forth (i) that the resolutions of its board of directors attached to
such certificate are in full force and effect with respect to the authorization
of the execution, delivery and performance of the obligations contained in the
Loan Documents to which it is a party, (ii) that the officers of such Guarantor
specified in such Secretary's Certificate are authorized to sign the Loan
Documents to which it is a party and who, until replaced by another officer or
officers duly authorized for that purpose, will act as its representative(s) for
the purposes of signing documents and giving notices and other communications in
connection with such Loan Documents and the transactions contemplated thereby,
(iii) specimen signatures of the officers so authorized, and (iv) that no
amendments or modifications have been made to the certificate or articles of
incorporation and the bylaws of such Guarantor since March 27, 1998. The
Administrative Agent and the Lenders may conclusively rely on such certificate
until the Administrative Agent receives notice in writing from such Guarantor to
the contrary.

     (c) The following legal opinions:

                                       19
<PAGE>
 
         (i)   An opinion of Akin, Gump, Strauss, Hauer & Feld, L.L.P., counsel
     to the Company, addressing such matters as may be reasonably requested by
     the Administrative Agent.

         (ii)  An opinion of Bennett Jones Verchere, special Canadian counsel to
     the Company, addressing such matters as may be reasonably requested by the
     Administrative Agent.

         (iii) An opinion of Ladner Downs, special British Columbia counsel to
     the Company, addressing such matters as may be reasonably requested by the
     Administrative Agent.

         (iv)  An opinion of Onebane, Bernard, Torian, Diaz, McNamera & Abell,
     addressing such matters as may be reasonably requested by the
     Administrative Agent.

     (d) The Notes and bills of exchange referred to in Section 2.01, duly
completed and executed.

     (e) The Guaranty Agreements, duly completed and executed.

     (f) All conditions precedent under the U. S. Credit Agreement shall have
been satisfied or waived to the satisfaction of the Administrative Agent.

     SECTION 6.02  SUBSEQUENT BORROWINGS.

     (a) The obligation of the Lenders to provide funds (other than with respect
to Base Rate Loans which are made pursuant to the terms hereof solely to replace
existing Bankers' Acceptances which have matured in the normal course on the
last day of an Interest Period therefor or pursuant to Section 5.02) to the
Company upon the occasion of each Borrowing or to accept and purchase a Bankers'
Acceptance hereunder is subject to the further conditions precedent that, as of
the date of such Loans or acceptance and purchase and after giving effect
thereto: (i) no Default or Event of Default shall have occurred and be
continuing; (ii) no event or circumstance having a Material Adverse Effect shall
have occurred since December 31, 1997, and (iii) the representations and
warranties made by the Company in Article VII and the other Loan Documents shall
be true in all material respects on and as of the date of such Borrowing with
the same force and effect as if made on and as of such date and following such
new Borrowing, except as such representations and warranties are modified to
give effect to transactions expressly permitted hereby or to the extent
expressly limited to an earlier date.

     (b) Each notice of Borrowing, conversion or renewal (other than Base Rate
Loans which are made pursuant to the terms hereof solely to replace existing
Bankers' Acceptances which have matured in the normal course on the last day of
an Interest Period there-for or pursuant to Section 5.02) and election for
acceptance or renewal of a Bankers' Acceptance by the Company hereunder shall
constitute a certification by the Company to the effect set forth in the
preceding sentence (both as of the date of such notice and, unless the Company
otherwise notifies the Administrative Agent, immediately following such
Borrowing).

                                       20
<PAGE>
 
                 ARTICLE VII:  REPRESENTATIONS AND WARRANTIES

     SECTION 7.01  INCORPORATION BY REFERENCE. Except as expressly stated in
this Agreement, each of the representations and warranties contained in 
Article VII of the U. S. Credit Agreement (together with the relevant provisions
of any other Section or Sections to which they refer, including definitions) is
hereby incorporated by reference into this Agreement and made a part of this
Agreement to the same extent as if those terms were set forth in full herein,
provided that, as and when appropriate, in the context: (a) any reference to
"Company" shall be deemed a reference to Ocean Energy Resources Canada, Ltd.;
(b) any reference to the "Guarantors" shall be deemed a reference to OEI-
Delaware and OEI-Louisiana; (c) any references to U.S. Governmental Requirements
shall, when appropriate in the context, be deemed to be references to
corresponding Canadian Governmental Requirements governing such subject matter,
if such exist; and (d) any other use of any capitalized term defined in both
this Agreement and the U. S. Credit Agreement shall be deemed to refer to such
term as defined in this Agreement, where appropriate in the context. As so
incorporated, the Company hereby makes and affirms each such representation and
warranty. All amendments, modifications, approvals, consents and waivers under
the U. S. Credit Agreement entered into by the parties to the U. S. Credit
Agreement with respect to Article VII thereof shall be binding upon the
Administrative Agent, the Lenders and the Company and shall constitute
corresponding amendments, modifications, approvals, consents and waivers hereto.

                     ARTICLE VIII:  AFFIRMATIVE COVENANTS

     The Company agrees that, so long as any of the Commitments are in effect
and until payment in full of all Loans and Bankers' Acceptances hereunder, all
interest thereon and all other amounts payable by the Company hereunder:

     SECTION 8.01  INCORPORATION BY REFERENCE. The Company will not, and will
not permit any of its Subsidiaries to, enter into, make, take, cause or suffer
to exist any transaction, action, omission or condition, if such transaction,
action, omission or condition constitutes a breach of any covenant set forth in
Sections 8.01, 8.02, 8.03, 8.04, 8.07 and 8.08 of the U.S. Credit Agreement,
which Sections (together with the relevant provisions of any other Section or
Sections of the U.S. Credit Agreement to which they refer, including
definitions) are hereby incorporated by reference into this Agreement and made a
part of this Agreement to the same extent as if those provisions were set forth
in full herein, provided that, for purposes of this Section, all defined terms
used in such provisions shall have the meanings set forth in the U.S. Credit
Agreement. As so incorporated, the Company hereby repeats and affirms each such
covenant and further covenants and agrees to strictly comply with each such
covenant. All amendments, modifications, approvals, consents and waivers under
the U. S. Credit Agreement entered into by the parties to the U. S. Credit
Agreement with respect to Article VIII thereof shall be binding upon the
Administrative Agent, the Lenders and the Company and shall constitute
corresponding amendments, modifications, approvals, consents and waivers hereto.

                                       21
<PAGE>
 
                        ARTICLE IX:  NEGATIVE COVENANTS

     The Company agrees that, so long as any of the Commitments are in effect
and until payment in full of all Loans and Bankers' Acceptances hereunder, all
interest thereon and all other amounts payable by the Company hereunder:

     SECTION 9.01  AFFIRMATION OF CERTAIN COVENANTS IN ARTICLE IX OF THE U. S.
CREDIT AGREEMENT. The Company will not, and will not permit any of its
Subsidiaries to, enter into, make, take, cause or suffer to exist any
transaction, action, omission or condition, if such transaction, action,
omission or condition constitutes a breach of any covenant set forth in Sections
9.01, 9.02, 9.03, 9.06, 9.07, 9.08, 9.09, 9.10, 9.11, 9.12, 9.13, 9.14, 9.15,
9.16, 9.17, 9.18, 9.19, 9.20, 9.21 and 9.22 of the U.S. Credit Agreement, which
Sections (together with the relevant provisions of any other Section or Sections
of the U.S. Credit Agreement to which they refer, including definitions) are
hereby incorporated by reference into this Agreement and made a part of this
Agreement to the same extent as if those provisions were set forth in full
herein, provided that, for purposes of this Section, all defined terms used in
such provisions shall have the meanings set forth in the U.S. Credit Agreement.
As so incorporated, the Company hereby repeats and affirms each such covenant
and further covenants and agrees to strictly comply with each such covenant. All
amendments, modifications, approvals, consents and waivers under the U. S.
Credit Agreement, entered into by the parties to the U. S. Credit Agreement with
respect to Article IX thereof, shall be binding upon the Administrative Agent,
the Lenders and the Company and shall constitute corresponding amendments,
modifications, approvals, consents and waivers hereto.

                         ARTICLE X:  EVENTS OF DEFAULT

     SECTION 10.01 EVENTS OF DEFAULT. If one or more Events of Default shall
occur and be continuing, then (a) in the case of an Event of Default other than
an Insolvency Event with respect to the Company and either Guarantor, the
Administrative Agent may and, upon request of the Required Lenders, shall, by
notice to the Company, cancel the Commitments and/or declare the principal
amount then outstanding of and the accrued interest on the Loans and all other
amounts payable by the Company hereunder and under the Notes and the Bankers'
Acceptances to be forthwith due and payable, whereupon such amounts shall be
immediately due and payable without presentment, demand, protest, notice of
intent to accelerate, notice of acceleration or other formalities of any kind,
all of which are hereby expressly waived by the Company; and (b) in the case of
the occurrence of an Insolvency Event with respect to the Company and either
Guarantor, the Commitments shall be automatically canceled and the principal
amount of the Loans, together with accrued interest, and all other amounts
payable by the Company hereunder and under the Notes and the Bankers'
Acceptances shall become automatically immediately due and payable without
presentment, demand, protest, notice of intent to accelerate, notice of
acceleration or other formalities of any kind, all of which are hereby expressly
waived by the Company and, in either case, the Administrative Agent and the
Lenders may pursue all rights and remedies of the Lenders and the Administrative
Agent under the other Loan Documents.

                                       22
<PAGE>
 
                     ARTICLE XI:  THE ADMINISTRATIVE AGENT

     SECTION 11.01 INCORPORATION BY REFERENCE. Sections 11.01 through 11.08 of
the U.S. Credit Agreement (together with the relevant provisions of any other
Section or Sections of the U.S. Credit Agreement to which they refer, including
definitions) are hereby incorporated by reference into this Agreement and made a
part of this Agreement to the same extent as if those provisions were set forth
in full herein, provided that, for purposes of such incorporated Sections, as
appropriate in the context, (i) references therein to "Administrative Agent,"
"Agreement," "Company" and "Lenders" shall mean such terms as defined in this
Agreement; (ii) references therein to "Loans" shall mean "Loans" and "Bankers
Acceptances" as such terms are defined in this Agreement; (iii) references
therein to "Notes" shall mean "Notes" and "Bankers Acceptances" as such terms
are defined in this Agreement; and (iv) as appropriate in the context, other
corresponding changes shall be made, mutatis mutandis.

                          ARTICLE XII:  MISCELLANEOUS

     SECTION 12.01 INCORPORATION BY REFERENCE. Sections 12.01, 12.02, 12.03,
12.05, 12.07, 12.08, 12.09, 12.11, 12.12, 12.14, 12.15, 12.17, 12.18 and 12.19
of the U.S. Credit Agreement (together with the relevant provisions of any other
Section or Sections of the U.S. Credit Agreement to which they refer, including
definitions) are hereby incorporated by reference into this Agreement and made a
part of this Agreement to the same extent as if those provisions were set forth
in full herein, provided that, for purposes of such incorporated Sections, as
appropriate in the context, (i) references therein to "Administrative Agent,"
"Agreement," "Company" and "Lenders" shall mean such terms as defined in this
Agreement; (ii) references therein to "Loans" shall mean "Loans" and "Bankers
Acceptances" as such terms are defined in this Agreement; (iii) references
therein to "Notes" shall mean "Notes" and "Bankers Acceptances" as such terms
are defined in this Agreement; and (iv) as appropriate in the context, other
corresponding changes shall be made, mutatis mutandis.

     SECTION 12.02 AMENDMENTS, ETC. Subject to the terms of the Intercreditor
Agreement, any provision of this Agreement or any other Loan Document may be
amended, modified or waived as provided in the U. S. Credit Agreement; provided
that no amendment, modification or waiver which extends the maturity of the
Loans or any Bankers' Acceptances, increases the Available Canadian
Subcommitment, or reduces the interest rate applicable to the Loans or the
Stamping Fee shall be effective without consent of all Lenders.

     SECTION 12.03 ASSIGNMENTS AND PARTICIPATIONS.

     (a) The Company may not assign its rights or obligations hereunder without
the prior consent of all of the Lenders and the Administrative Agent.

     (b) Each Lender may, upon the written consent of the Company and the
Administrative Agent, which consent shall not be unreasonably withheld or
delayed, assign to one or more assignees all or a portion of its rights and
obligations under this Agreement pursuant to an Assignment and Acceptance
Agreement substantially in the form of Exhibit C (an "Assignment and
Acceptance") provided, however, that (i) any such assignment shall be in the
aggregate amount of at least $5,000,000, the entire amount of the Lender's
Commitment, if less,

                                       23
<PAGE>
 
or such lesser amount to which the Company has consented, (ii) the assignee
shall pay to the Administrative Agent a processing and recordation fee of
$3,500; provided that such fee shall not be payable in conjunction with any
assignments occurring within 30 days of the Effective Date, and (iii) the
assignee is a resident of Canada for purposes of the Income Tax Act (Canada).
Any such assignment will become effective upon the issuance by the
Administrative Agent of a letter of acknowledgment reflecting such assignment
and the resultant effects thereof on the Commitments of the assignor and
assignee, and the principal amount outstanding of the Loans owed to the assignor
and assignee, the Administrative Agent hereby agreeing to effect such issuance
no later than five (5) Business Days after its receipt of an Assignment and
Acceptance executed by all parties thereto. Promptly after receipt of an
Assignment and Acceptance executed by all parties thereto, the Administrative
Agent shall send to the Company a copy of such executed Assignment and
Acceptance. Upon receipt of such executed Assignment and Acceptance, the
Company, will, at its own expense, execute and deliver new Notes to the assignor
and/or assignee, as appropriate, in accordance with their respective interests
as they appear on the Administrative Agent's letter of acknowledgment. Upon the
effectiveness of any assignment pursuant to this Section, the assignee will
become a "Lender," if not already a "Lender," for all purposes of this Agreement
and the other Loan Documents. The assignor shall be relieved of its obligations
hereunder to the extent of such assignment (and if the assigning Lender no
longer holds any rights or obligations under this Agreement, such assigning
Lender shall cease to be a "Lender" hereunder except for the purposes of 
Section 12.04 hereof and the Sections referred to therein). The Administrative
Agent will prepare on the last Business Day of each month during which an
assignment has become effective pursuant to this Section a revised Annex I to
the U. S. Credit Agreement giving effect to all such assignments effected during
such month, and will promptly provide the same to the Company and each of the
Lenders.

     (c) Each Lender may transfer, grant or assign participations in all or any
part of such Lender's interests hereunder pursuant to this subsection to any
Person, provided that: (i) such Lender shall remain a "Lender" for all purposes
of this Agreement and the transferee of such participation shall not constitute
a "Lender" hereunder; and (ii) no participant under any such participation shall
have rights to approve any amendment to or waiver of this Agreement, the Notes
or any Loan Document except to the extent such amendment or waiver would (x)
extend the Termination Date, (y) reduce the interest rate (other than as a
result of waiving the applicability of any post-default increases in interest
rates) or fees applicable to any of the Commitments or Loans in which such
participant is participating, or postpone the payment of any thereof, or (z)
release all or substantially all of the collateral (except as expressly provided
in the Loan Documents) supporting any of the Commitments or Loans in which such
participant is participating. In the case of any such participation, the
participant shall not have any rights under this Agreement or any of the Loan
Documents (the participant's rights against the granting Lender in respect of
such participation to be those set forth in the agreement with such Lender
creating such participation), and all amounts payable by the Company hereunder
shall be deter-mined as if such Lender had not sold such participation, provided
that if the participant is a resident of Canada for purposes of the Income Tax
Act (Canada) and has its principal office in Canada, such participant shall be
entitled to receive additional amounts under Article V on the same basis as if
it were a Lender. In addition, each agreement creating any participation must
include agreements by the participant to be bound by the provisions of 
Section 12.14 of the U.S. Credit Agreement as incorporated herein and forbidding
the transfer, assignment or sub-participation of such participation.

                                       24
<PAGE>
 
     (d) The Lenders may furnish any information concerning the Company in the
possession of the Lenders from time to time to assignees and participants
(including prospective assignees and participants); provided that, such Persons
agree in writing to be bound by the provisions of Section 12.14 of the U.S.
Credit Agreement as incorporated herein by Section 12.01.

     SECTION 12.04 SURVIVAL. The obligations of the Company, the Administrative
Agent and the Lenders under Sections 5.01, 5.03 and 5.05 hereof, and 
Sections 12.03 and 12.14 of the U.S. Credit Agreement as incorporated herein by
Section 12.01 shall survive the repayment of the Loans and the termination of 
the Commitments.

     SECTION 12.05 GOVERNING LAW; SUBMISSION TO JURISDICTION.

     (a) THIS AGREEMENT AND THE NOTES SHALL BE GOVERNED BY, AND CONSTRUED IN
ACCORDANCE WITH, THE LAWS OF THE PROVINCE OF ALBERTA, CANADA.

     (b) ANY LEGAL ACTION OR PROCEEDING WITH RESPECT TO THIS AGREEMENT, THE
NOTES, ANY BANKERS' ACCEPTANCE, OR THE OTHER LOAN DOCUMENTS MAY BE BROUGHT IN
THE COURTS OF TORONTO, ONTARIO, AND, BY EXECUTION AND DELIVERY OF THIS
AGREEMENT, THE COMPANY HEREBY ACCEPTS FOR ITSELF AND (TO THE EXTENT PERMITTED BY
LAW) IN RESPECT OF ITS PROPERTY, GENERALLY AND UNCONDITIONALLY, THE JURISDICTION
OF THE AFORESAID COURTS. THE COMPANY HEREBY IRREVOCABLY WAIVES ANY OBJECTION,
INCLUDING, WITHOUT LIMITATION, ANY OBJECTION TO THE LAYING OF VENUE OR BASED ON
THE GROUNDS OF FORUM NON CONVENIENS, WHICH IT MAY NOW OR HEREAFTER HAVE TO THE
BRINGING OF ANY SUCH ACTION OR PROCEEDING IN SUCH RESPECTIVE JURISDICTIONS. THIS
SUBMISSION TO JURISDICTION IS NONEXCLUSIVE AND DOES NOT PRECLUDE THE
ADMINISTRATIVE AGENT OR ANY LENDER FROM OBTAINING JURISDICTION OVER THE COMPANY
IN ANY COURT OTHERWISE HAVING JURISDICTION.

     (c) Nothing herein shall affect the right of the Administrative Agent or
any Lender to serve process in any manner permitted by law or to commence legal
proceedings or otherwise proceed against the Company in any other jurisdiction.

     (d) THE COMPANY, THE ADMINISTRATIVE AGENT AND EACH LENDER HEREBY (i)
IRREVOCABLY AND UNCONDITIONALLY WAIVE, TO THE FULLEST EXTENT PERMITTED BY LAW,
TRIAL BY JURY IN ANY LEGAL ACTION OR PROCEEDING RELATING TO THIS AGREEMENT OR
ANY LOAN DOCUMENT AND FOR ANY COUNTERCLAIM THEREIN; (ii) IRREVOCABLY WAIVE, TO
THE MAXIMUM EXTENT NOT PROHIBITED BY LAW, ANY RIGHT IT MAY HAVE TO CLAIM OR
RECOVER IN ANY SUCH LITIGATION ANY SPECIAL, EXEMPLARY, PUNITIVE OR CONSEQUENTIAL
DAMAGES, OR DAMAGES OTHER THAN, OR IN ADDITION TO, ACTUAL DAMAGES; (iii) CERTIFY
THAT NO PARTY HERETO NOR ANY REPRESENTATIVE OR AGENT OR COUNSEL FOR ANY PARTY
HERETO HAS REPRESENTED, EXPRESSLY OR OTHERWISE, OR IMPLIED THAT SUCH PARTY

                                       25
<PAGE>
 
WOULD NOT, IN THE EVENT OF LITIGATION, SEEK TO ENFORCE THE FOREGOING WAIVERS,
AND (iv) ACKNOWLEDGE THAT IT HAS BEEN INDUCED TO ENTER INTO THIS AGREEMENT, THE
LOAN DOCUMENTS AND THE TRANSACTIONS CONTEMPLATED HEREBY AND THEREBY BY, AMONG
OTHER THINGS, THE MUTUAL WAIVERS AND CERTIFICATIONS CONTAINED IN THIS 
SECTION 12.05.

     SECTION 12.06 EFFECTIVENESS. This Agreement shall not be effective until
the date (the "Effective Date") that it is delivered to the Lenders in Toronto,
Ontario, Canada, accepted by the Lenders in such place, and executed by the
Lenders in such place.

     SECTION 12.07 INTERPRETATION OF LOAN DOCUMENTS.  If in the event of any
conflict between the terms of Articles VII, VIII, IX and X of this Agreement and
the representations, warranties, covenants or events of default contained in any
of the Loan Documents (other than the U. S. Credit Agreement), the terms of
Articles VII, VIII, IX and X of this Agreement, as appropriate, shall govern.

                          [SIGNATURES BEGIN NEXT PAGE]

                                       26
<PAGE>
 
     The parties hereto have caused this Agreement to be duly executed as of the
day and year first above written.

                                  COMPANY:

                                  OCEAN ENERGY RESOURCES CANADA, LTD.

                                  By:
                                     ------------------------------------------
                                     Jonathan M. Clarkson
                                     Senior Vice President
                                     Chief Financial Officer

                                  10th Floor, First Canadian Centre
                                  Suite 1000
                                  350-7th Avenue S.W.
                                  Calgary, Alberta  T2P 3N9
                                  Telecopier No:  (403) 298-8984
                                  Telephone No.:  (403) 264-3333

                                  with a copy to:

                                  1201 Louisiana, Suite 1400
                                  Houston, Texas 77002
                                  Telecopier No.: (713) 653-5024
                                  Telephone No.:  (713) 654-9110
                                  Attention:  Frank D. Willoughby
                                  and Robert K. Reeves


                                      S-1
<PAGE>
 
                                  THE CHASE MANHATTAN BANK OF CANADA

                                  By:
                                     ------------------------------------------
                                     Christine Chan
                                     Vice President

                                  Lending Office for Base Rate  Loans:

                                  The Chase Manhattan Bank of Canada
                                  1 First Canadian Place
                                  100 King Street West
                                  Suite 6900, P.O. Box 106
                                  Toronto, Ontario M5X 1A4

                                  Address for Notices:

                                  The Chase Manhattan Bank of Canada
                                  1 First Canadian Place
                                  100 King Street West
                                  Suite 6900, P.O. Box 106
                                  Toronto, Ontario M5X 1A4
                                  Attn:  Christine Chan

                                  with a copy to:

                                  Chase Bank of Texas, National Association
                                  600 Travis
                                  Houston, Texas  77002
                                  Telecopier No.:  (713) 216-4117
                                  Telephone No.:  (713) 216-8869
                                  Attention:  Peter Licalzi


                                      S-2
<PAGE>
 
                                  TORONTO DOMINION BANK

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


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


                                  Lending Office for Base Rate Loans:

                                  8th Floor
                                  Home Oil Tower
                                  324 8th Ave. S.W.
                                  Calgary, Alberta T2P 2Z2

                                  Address for Notices:

                                  Toronto Dominion Bank
                                  Corporate Investment Banking Group
                                  8th Floor
                                  Home Oil Tower
                                  324 8th Ave. S.W.
                                  Calgary, Alberta T2P 2Z2
                                  Telecopier No.: (403) 292-2772
                                  Telephone No.: (403) 299-7918
                                  Attention:  Phil Ghali



                                      S-3
<PAGE>
 
                                  THE CHASE MANHATTAN BANK OF CANADA, as
                                  Administrative Agent



                                  By:
                                     ------------------------------------------
                                     Christine Chan
                                     Vice President

                                  Address for Notices to Chase Administrative
                                  Agent:

                                  The Chase Manhattan Bank of Canada
                                  1 First Canadian Place
                                  100 King Street West
                                  Suite 6900, P.O. Box 106
                                  Toronto, Ontario M5X 1A4
                                  Attn:  Christine Chan

                                  Telecopier No.: (416) 216-4161
                                  Telephone No.:  (416) 216-4133



                                      S-4
<PAGE>
 
                                   EXHIBIT A

                                 FORM OF NOTE
                                  
$________________                                          ______________, 199__


     FOR VALUE RECEIVED, Ocean Energy Resources Canada, Ltd., a company
continued under the laws of the Province of British Columbia (the "Company"),
hereby promises to pay to the order of ___________________ (the "Lender"), for
the account of its Applicable Lending Office as provided for by the Credit
Agreement (as hereinafter defined), at the Principal Office of The Chase
Manhattan Bank of Canada, as Administrative Agent, the principal sum of
_________________________________________________ ($__________) (or such lesser
amount as shall equal the aggregate unpaid principal amount of the Loans made by
the Lender to the Company under the Credit Agreement) in lawful money of Canada
and in immediately available funds, on the dates and in the principal amounts
provided in the Credit Agreement, and to pay interest on the unpaid principal
amount of each such Loan, at such Principal Office, in like money and funds, for
the period commencing on the date of such Loan until such Loan shall be paid in
full, at the rates per annum and on the dates provided in the Credit Agreement.

     The date, amount, interest rate and maturity of each Loan made by the
Lender to the Company, and each payment made on account of the principal
thereof, shall be recorded by the Lender on its books and, prior to any transfer
of this Note, endorsed by the Lender on the schedules attached hereto or any
continuation thereof.

     This Note is a Note referred to in that certain Amended and Restated Credit
Agreement dated as of July 8, 1998 between the Company, each of the lenders that
is a party thereto and The Chase Manhattan Bank of Canada, as the administrative
agent (as such may be amended from time to time, the "Credit Agreement"), and
evidences the Loans made by the Lender thereunder.  Capitalized terms used in
this Note have the respective meanings assigned to them in the Credit Agreement.

     This Note is issued pursuant to the Credit Agreement and is entitled to the
benefits provided for in the Credit Agreement and the Loan Documents.  The
Credit Agreement provides for the acceleration of the maturity of this Note upon
the occurrence of certain events and for prepayments of Loans upon the terms and
conditions specified therein and other pertinent terms.



                                      A-1
<PAGE>
 
     THIS NOTE SHALL BE GOVERNED BY AND CONSTRUED IN ACCORDANCE WITH THE LAWS OF
THE PROVINCE OF ALBERTA, CANADA.

                                  Ocean Energy Resources Canada, Ltd.



                                  By:
                                     ------------------------------------------
                                     Jonathan M. Clarkson
                                     Senior Vice President
                                     Chief Financial Officer



                                      A-2
<PAGE>
 
                                   SCHEDULE
                                      OF
                  LOAN AND PAYMENTS OF PRINCIPAL AND INTEREST
                                        

<TABLE>
<CAPTION>
                      Amount of                  Unpaid
                      Principal    Amount of    Principal
         Amount of     Paid or     Interest      Balance     Notation
 Date      Loan        Prepaid       Paid        of Loan     Made by
<S>      <C>          <C>          <C>          <C>          <C>

-----   -----------  -----------  -----------  -----------  -----------  
-----   -----------  -----------  -----------  -----------  -----------  
-----   -----------  -----------  -----------  -----------  -----------   
-----   -----------  -----------  -----------  -----------  -----------   
-----   -----------  -----------  -----------  -----------  -----------   
-----   -----------  -----------  -----------  -----------  -----------   
-----   -----------  -----------  -----------  -----------  -----------   

</TABLE>

                                      S-1
<PAGE>
 
                                   EXHIBIT B

                          FORM OF BANKER'S ACCEPTANCE






                                      B-1
<PAGE>
 
                                   EXHIBIT C

                                   [FORM OF]

                           ASSIGNMENT AND ACCEPTANCE
                           
Dated: _____________, 199__

     Reference is made to that certain Amended and Restated Credit Agreement
dated as of July 8, 1998 among Ocean Energy Resources Canada, Ltd., a company
continued under the laws of the Province of British Columbia (the "Company"),
The Chase Manhattan Bank of Canada, as Administrative Agent, and the lenders
parties thereto (such Amended and Restated Credit Agreement together with all
amendments and supplements thereto being the "Credit Agreement").  Capitalized
terms used herein and not otherwise defined shall have the meanings assigned to
such terms in the Credit Agreement.  This Assignment and Acceptance, between the
Assignor (as defined and set forth on Schedule I hereto and made a part hereof)
and the Assignee (as defined and set forth on Schedule I hereto and made a part
hereof) is dated as of the Effective Date (as set forth on Schedule I hereto and
made a part hereof).

     1.  The Assignor hereby irrevocably sells and assigns to the Assignee
without recourse to the Assignor, and the Assignee hereby irrevocably purchases
and assumes from the Assignor without recourse to the Assignor, as of the
Effective Date, an undivided interest (the "Assigned Interest") in and to all
the Assignor's rights and obligations under the Credit Agreement respecting
those, and only those, Commitments, Loans and Bankers' Acceptances contained in
the Credit Agreement as are set forth on Schedule I, in a principal amount as
set forth on Schedule I.

     2.  The Assignor (i) represents and warrants that it owns the Assigned
Interest free and clear from any lien or adverse claim; (ii) other than the
representation and warranty set forth in clause (i) above, makes no
representation or warranty and assumes no responsibility with respect to any
statements, warranties or representations made in or in connection with the
Credit Agreement or any other instrument, document or agreement delivered in
connection therewith, or the execution, legality, validity, enforceability,
genuineness, sufficiency or value of the Credit Agreement, or any other
instrument or document furnished pursuant thereto, other than 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; (iii) makes no
representation or warranty and assumes no responsibility with respect to the
financial condition of either OEI-Delaware or the Company or the performance or
observance by OEI-Delaware or any of its Subsidiaries, including the Company, or
of any of their respective obligations under the Credit Agreement, or any other
instrument or document furnished pursuant thereto; and (iv) attaches the Notes
held by it evidencing the Assigned Interest and requests that the Company
exchange such Notes for new Notes payable to the Assignor (if the Assignor has
retained any interest in the Assigned Interest) and new Notes payable to the
Assignee in the respective amounts which reflect the assignment being made
hereby (and after giving effect to any other assignments which have become
effective on the Effective Date).



                                      C-1
<PAGE>
 
     3.  The Assignee (i) represents and warrants that it is legally authorized
to enter into this Assignment and Acceptance; (ii) confirms that it has received
a copy of the Credit Agreement, together with copies of the financial statements
referred to in Section 7.02 of the U.S. Credit Agreement, or if later, the most
recent financial statements delivered pursuant to Section 8.01 thereof, and such
other documents and information as it has deemed appropriate to make its own
credit analysis; (iii) agrees that it will, independently and without reliance
upon either the Administrative Agent, any other Lender or the Assignor 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; (iv) agrees that it will be bound by the provisions of the
Credit Agreement and will perform in accordance with its terms all the
obligations which by the terms of the Credit Agreement are required to be
performed by it and (v) represents and warrants that it is a resident of Canada
for purposes of the Income Tax Act (Canada) and has its principal office in
Canada.

     4.  Following the execution of this Assignment and Acceptance, it will be
delivered to the Company effective as of the Effective Date (which Effective
Date shall, unless otherwise agreed, be at least five (5) Business Days after
the execution of this Assignment and Acceptance).

     5.  Upon delivery to the Company, all payments under the Credit Agreement
in respect of the Assigned Interest (including without limitation, all payments
of principal, interest and fees with respect thereto) for the period up to, but
not including, the Effective Date, shall be made to the Assignor, and for the
period from and after the Effective Date shall be made to the Assignee. Assignor
and Assignee hereby agree that if Assignor receives any of the payments referred
to in the preceding sentence which should have been made to Assignee, or if
Assignee receives any of the payments referred to in the previous sentence which
should have been made to Assignor, such payments shall promptly be paid by
Assignor to Assignee, or by Assignee to Assignor, as the case may be, in full.

     6.  From and after the Effective Date, (i) the Assignee shall be a party to
the Credit Agreement and, to the extent provided in this Assignment and
Acceptance and Section 12.03 of the Credit Agreement, have the rights and
obligations thereunder, and (ii) the Assignor shall, to the extent provided in
this Assignment and Acceptance and Section 12.03 of the Credit Agreement,
relinquish its rights and be released from its obligations under the Credit
Agreement.

     7.  THIS ASSIGNMENT AND ACCEPTANCE SHALL BE GOVERNED BY, AND CONSTRUED IN
ACCORDANCE WITH, THE LAWS OF THE PROVINCE OF ALBERTA, CANADA.



                                      C-2
<PAGE>
 
     IN WITNESS WHEREOF, the parties hereto have caused this Assignment and
Acceptance to be executed by their respective duly authorized officers on
Schedule I hereto.

                                  as Assignor



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


                                  as Assignee



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


                                  APPROVED:

                                  Ocean Energy Resources Canada, Ltd.



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


                                  THE CHASE MANHATTAN BANK OF
                                  CANADA, as Administrative Agent



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



                                      C-3
<PAGE>
 
                    SCHEDULE I TO ASSIGNMENT AND ACCEPTANCE

<TABLE>
<CAPTION>
<S>                                                                       <C>
Assignor:
         -------------------------------------------------------
     Total Commitment of Assignor Prior to Effective Date:                $
                                                                           ------------------------
     Total Commitment of Assignor After Effective Date:                   $
                                                                           ------------------------

Assignee:
         -------------------------------------------------------
     Total Commitment of Assignee Prior to Effective Date:                $
                                                                           ------------------------
     Total Commitment of Assignee After Effective Date:                   $
                                                                           ------------------------

Effective Date of Assignment:                           , 199

Amount of Total Commitment Assigned:                                      $
                                                                           ------------------------
</TABLE>

<TABLE>
<CAPTION>
<S>                                                   <C>
               Principal Amount                                     Percentage Assigned
           (or amount of Commitment)                             (Shown as a percentage of
                   Assigned                                        aggregate Commitments)
-----------------------------------------------    --------------------------------------------------
 
     $                                                                                     %
      -------------------------                                                ------------
                                                      Assignee's
                                                      Address for Notice:
 
                                                      ---------------------------------------------
                                                      ---------------------------------------------
 
                                                      Lending Office:
 
                                                      ---------------------------------------------
                                                      --------------------------------------------- 
                                                      Attn:
                                                           ----------------------------------------
                                                      Telex No.:
                                                                -----------------------------------
                                                      Telecopy No.:
                                                                   --------------------------------
                                                      Telephone No.:
                                                                    -------------------------------
</TABLE>


                                     SI-1
<PAGE>
 
                                   EXHIBIT D

                                   [FORM OF]

                   BORROWING, RENEWAL AND CONVERSION REQUEST

_____________________, 199__

     Ocean Energy Resources Canada, Ltd., a company continued under the laws of
the Province of British Columbia (the "Company"), pursuant to the Amended and
Restated Credit Agreement dated as of July 8, 1998 among the Company, The Chase
Manhattan Bank of Canada, as Administrative Agent, and the lenders parties
thereto (such Amended and Restated Credit Agreement together with all amendments
and supplements thereto being the "Credit Agreement"), hereby makes the requests
indicated below (unless otherwise defined herein, capitalized terms are defined
in the Credit Agreement):

1.   Borrowings:

     (a) Aggregate amount of new Borrowings to be $________________;

     (b) Requested funding date is _________________, 199__;

     (c) $_____________________ of such Borrowings are to be Bankers'
         Acceptances;

         $_____________________ of such Borrowings are to be Base Rate Loans;
         and

     (d) Length of Interest Period for Bankers' Acceptances is:

         _________________________.

2.   Bankers' Acceptance Renewals for Bankers' Acceptances maturing on
     ______________:

     (a) Aggregate amount to be renewed as Bankers' Acceptances is
         $_______________;

     (b) Aggregate amount to be converted to Base Rate Loans is
         $_______________;

     (c) Length of Interest Period for renewed (or reissued) Bankers'
         Acceptances is ________________________.

3.   Conversion of Outstanding Base Rate Loans by issuance of Bankers'
     Acceptances:

     Convert $__________________ of the outstanding Base Rate Loans by issuance
     of Bankers' Acceptances on ____________________ with an Interest Period of
     ______________________.

     The undersigned certifies that he is the _____________________ of the
Company, and that as such he is authorized to execute this certificate on behalf
of the Company.  The undersigned further certifies, represents and warrants on
behalf of the Company that the


                                      D-1
<PAGE>
 
Company is entitled to receive the requested Borrowing, continuation or
conversion under the terms and conditions of the Credit Agreement.

                                  Ocean Energy Resources Canada, Ltd.

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


                                      D-2