<PAGE>

                                                                 EXHIBIT 10.3



                        FOURTH AMENDMENT

                               to

                        CREDIT AGREEMENT

                          by and among

                      WILLBROS GROUP, INC.,

         THE DESIGNATED SUBSIDIARIES FROM TIME TO TIME,

                               and

                       ABN AMRO BANK N.V.,
                            as Agent,

                CREDIT LYONNAIS NEW YORK BRANCH,
                          as Co-Agent,

                               and

               THE SEVERAL FINANCIAL INSTITUTIONS
                FROM TIME TO TIME PARTIES HERETO


                  Effective as of June 30, 2000



<PAGE>


                       FOURTH AMENDMENT TO
                        CREDIT AGREEMENT
                        ----------------


     This FOURTH AMENDMENT TO CREDIT AGREEMENT (this "Fourth
                                                      ------
Amendment"), executed as of August 14, 2000, and effective as of
---------
June 30, 2000 (the "Amendment Effective Date"), is by and among
                    ------------------------
WILLBROS GROUP, INC., a Republic of Panama corporation ("WGI" or
                                                         ---
the "Company"); certain Designated Subsidiaries (WGI and such
     -------
Designated Subsidiaries collectively, the "Borrowers" and
                                           ---------
individually, a "Borrower"); the several financial institutions
                 --------
from time to time parties to the Credit Agreement defined below
(individually, together with its successors and assigns, a "Bank"
                                                            ----
and, collectively, the "Banks"); CREDIT LYONNAIS NEW YORK BRANCH,
                        -----
individually as a Bank and as Co-Agent; and ABN AMRO BANK N.V.,
individually ("ABN AMRO") as a Bank and as agent for the Banks
               --------
(in such capacity, the "Agent").
                        -----

                        R E C I T A L S:
                        - - - - - - - -

     A.   The Borrowers, the Agent and the Banks are parties to
that certain Credit Agreement dated as of February 20, 1997, as
amended by First Amendment to Credit Agreement dated as of April 2,
1998, by Second Amendment to Credit Agreement dated as of
October 1, 1998 and by Third Amendment to Credit Agreement
effective as of June 30, 2000 (such Credit Agreement, together
with any amendments, modifications or supplements thereto,
referred to herein as the "Credit Agreement"), pursuant to which
                           ----------------
the Lenders agreed to make certain loans to and extensions of
credit on behalf of the Borrowers upon the terms and conditions
as provided therein; and

     B.   The Borrowers have requested and the Agent, the Co-
Agent and the Banks have agreed to amend certain provisions of
the Credit Agreement;

     NOW, THEREFORE, in consideration of the premises and the
mutual covenants herein contained and for good and valuable
consideration, the receipt and sufficiency of which are hereby
acknowledged, the parties hereto agree as follows:

                            ARTICLE I
                           DEFINITIONS
                           -----------

     1.1  Terms Defined in the Credit Agreement.  Each term
          -------------------------------------
defined in the Credit Agreement and used herein without
definition shall have the meaning assigned to such term in the
Credit Agreement, unless expressly provided to the contrary.
Unless otherwise indicated, all section references in this Fourth
Amendment refer to the Credit Agreement.

                           ARTICLE II
                 AMENDMENTS TO CREDIT AGREEMENT
                 ------------------------------

     2.1  Amendments to Section 1.1.
          -------------------------

          (a)  The definitions of "Agreement", "Applicable
                                   ---------    ----------
     Margin", "CDLC Fee Percentage", "Commitment Fee Percentage",
     ------    -------------------    -------------------------
     "Financial SBLC Fee Percentage",
      -----------------------------




<PAGE>


     "Nonfinancial SBLC Fee Percentage" and "Pricing Schedule"
      --------------------------------       ----------------
     are hereby amended to read in their entirety as follows:

                    "Agreement" means this Credit Agreement, as
                     ---------
          amended by the First Amendment, the Second Amendment,
          the Third Amendment, and the Fourth Amendment and as
          further amended from time to time.

                    "Applicable Margin" means, on any day, the
                     -----------------
          per annum percentage, expressed in basis points, beside
          the label "Applicable Margin" in the appropriate table
          in the Pricing Schedule and, when applicable,
          determined by finding the Company's Interest Coverage
          Ratio on such date.  The Applicable Margin shall be
          adjusted on the date required by Section 7.1 for the
                                           -----------
          delivery of each of the Company's financial statements.

                    "CDLC Fee Percentage" means, on any day, the
                     -------------------
          per annum percentage, expressed in basis points, beside
          the label "CDLC" in the appropriate table in the
          Pricing Schedule and, when applicable, determined by
          finding the Company's Interest Coverage Ratio on such
          date.  The CDLC Fee Percentage shall be adjusted on the
          date required by Section 7.1 for the delivery of each
                           -----------
          of the Company's financial statements.

                    "Commitment Fee Percentage" means, on any
                     -------------------------
          day, the per annum percentage, expressed in basis
          points, beside the label "Commitment Fee" in the
          appropriate table in the Pricing Schedule and, when
          applicable, determined by finding the Company's
          Interest Coverage Ratio on such date.  The Commitment
          Fee Percentage shall be adjusted on the date required
          by Section 7.1 for the delivery of each of the
             -----------
          Company's financial statements.

                    "Financial SBLC Fee Percentage" means, on any
                     -----------------------------
          day, the per annum percentage, expressed in basis
          points, beside the label "Financial SBLCs" in the
          appropriate table in the Pricing Schedule and, when
          applicable, determined by finding the Company's
          Interest Coverage Ratio on such date.  The Financial
          SBLC Fee Percentage shall be adjusted on the date
          required by Section 7.1 for the delivery of each of the
                      -----------
          Company's financial statements.

                    "Nonfinancial SBLC Fee Percentage" means, on
                     --------------------------------
          any day, the per annum percentage, expressed in basis
          points, beside the label "Nonfinancial SBLCs" in the
          appropriate table in the Pricing Schedule and, when
          applicable, determined by finding the Company's
          Interest Coverage Ratio on such date. The Nonfinancial
          SBLC Fee Percentage shall be adjusted on the date
          required by Section 7.1 for the delivery of each of the
                      -----------
          Company's financial statements.

                    "Pricing Schedule" means the schedule of that
                     ----------------
          name attached as Exhibit A to the Fourth Amendment.
                           ---------

                              - 2 -



<PAGE>


          (b)  The following definitions of "Interest Coverage
                                             -----------------
     Ratio" and "Fourth Amendment" are hereby added where
     -----       ----------------
     alphabetically appropriate:

                    "Interest Coverage Ratio" means the ratio of
                     -----------------------
          (a) EBIT for the immediately preceding four quarters to
          (b) Consolidated Net Interest Expense for the
          immediately preceding four quarters.

                    "Fourth Amendment" means the Fourth Amendment
                     ----------------
          to Credit Agreement effective as of June 30, 2000, by
          and among the Company, the Agent, the Co-Agent and the
          Banks.

     2.2  Amendment to Section 7.1(e).  Section 7.1(e) is hereby
          ---------------------------
amended to read in its entirety as follows:

          (e)  (i)  until such time that the Company has
     maintained for two consecutive quarters an Interest Coverage
     Ratio (measured as of the last day of each fiscal quarter
     for the four quarters then ended) of 2.5 to 1.0 or greater,
     as soon as possible after the end of each calendar month,
     but in any event not later than 45 days after the end of
     each calendar month, except for December and January which
     shall be not later than 60 days after the end of such
     months, financial statements similar to those referred to in
     paragraphs (c) and (d) of this Section 7.1 for such month,
     ----------------------         -----------
     in addition to the requirements set forth in such
     paragraphs, which financial statements shall set forth the
     financial information required by paragraph (c) or (d), as
                                       --------------------
     applicable, for such month and include current EBITDA
     calculations of WGI and consolidating income statements and
     balance sheets for such month of each of WGI showing WGI,
     WII, Rogers & Phillips, Inc. and WUSA, and WUSA showing
     WUSA, WESCO and WEI, and (ii) upon request by the Agent,
     reports as to the location of property that is collateral
     under any Security Document including information as to
     owner, net book value and location, certified by an
     appropriate Responsible Officer of the Company.

     2.3  Amendment to Section 8.3(g); Addition of
          ----------------------------------------
Section 8.3(h).  Section 8.3(g) is hereby amended, and a new
--------------
Section 8.3(h) is hereby added, together to read in their
entirety as follows:

               (g)  Permitted Acquisitions and Investments not to
     exceed $62,500,000 in the aggregate; provided that (i) at
     the time of any such proposed Permitted Acquisition and
     Investment there are no outstanding Loans or any Letter of
     Credit Obligations for any financial Standby Letters of
     Credit under the Credit Agreement, (ii) none of the proceeds
     of the Loans and no Letter of Credit shall be used for the
     purpose of any Permitted Acquisition and Investment, and
     (iii) the Company would be in compliance with the financial
     covenants set forth in this Agreement, after giving effect
     to such transaction for the period of the most recently
     ended four consecutive fiscal quarters preceding such
     transaction, assuming such transaction had occurred on the
     first day of such period; and

               (h)  acquisitions that are Permitted Acquisitions
     and Investments with shares of the Company's stock as the
     sole consideration (except that Loan proceeds up to an
     aggregate of the lesser of $750,000 or 15% of the value of
     the total consideration may be

                              - 3 -



<PAGE>


     used to reimburse transactional expenses payable by the
     Company in connection with each such acquisitions); provided
                                                         --------
     that after giving effect pro forma to any such acquisition,
     no Default or Event of Default would have occurred or exist;
     provided further, that such stock is not mandatorily
     --------
     redeemable by the holder thereof, is not subject to any
     repurchase requirements by the Company and does not have a
     scheduled maturity date prior to the day that is 180 days
     after the Commitment Termination Date.


     2.4  Amendment to Section 8.12.  Section 8.12 is hereby
          -------------------------
amended to read in its entirety as follows:

          8.12 Consolidated Net Worth.  The Company shall not
               ----------------------
     permit its Consolidated Net Worth to be less than the sum of
     (a) $65.0 million plus (b) 50% of the Company's cumulative
     net income for the calendar year to date (without deduction
     for loss) at the end of each fiscal quarter, starting with
     the fiscal quarter beginning July 1, 2000.

     2.5  Amendment to Section 8.14.  Section 8.14 is hereby
          -------------------------
amended to read in its entirety as follows:

          8.14 Minimum EBITDA; Interest Coverage Ratio.
               ---------------------------------------

               (a)  The Company shall not permit EBITDA for the
     four quarters then most recently ended (i) on June 30, 2000,
     to be less than $11.4 million, (ii) on September 30, 2000,
     to be less than $12.7 million, (iii) on December 31, 2000,
     to be less than $11.3 million, (iv) on March 31, 2001, to be
     less than $15.3 million, (v) on June 30, 2001, to be less
     than $17.3 million, and (vi) on September 30, 2001, to be
     less than $24.8 million.

               (b)  Beginning with the fiscal quarter ending on
     December 31, 2001, the Company shall not permit the Interest
     Coverage Ratio to be less than 2.50 to 1.00 at the end of
     any fiscal quarter.

     2.6  Amendment to Section 8.15.  Section 8.15 is hereby
          -------------------------
amended to read in its entirety as follows:

          8.15 Indebtedness.  The Company shall not at any time
               ------------
     (whether at the end of a fiscal quarter or otherwise)
     create, incur, assume or suffer to exist any Indebtedness if
     immediately after such creation, incurrence, sufferance and
     after giving effect to it:

               (a)  the ratio of the Company's Funded
     Indebtedness at such time to the Total Capitalization as of
     such date of the Company would exceed (i) .40 to 1.00 at any
     time prior to April 1, 2001, or (ii) 0.50 to 1.00 at all
     other times.

                              - 4 -



<PAGE>



               (b)  the ratio of the Company's Funded
     Indebtedness at such time to EBITDA for the four fiscal
     quarters most recently ended at such time would exceed the
     following ratios for the periods indicated:

               <TABLE>
               <CAPTION>

               Period                             Applicable Ratio
               ------                             ----------------

               <S>                                <C>

               through June 30,2000               3.50 to 1.00
               July 1, 2000 through
                March 31, 2001                    3.00 to 1.00
               on and after April 1, 2001         2.75 to 1.00

               </TABLE>

     2.7  Borrowing Base Addendum.  The "Borrowing Base Addendum"
          -----------------------
attached hereto is made a part hereof for all purposes, and upon
the Amendment Effective Date, the Borrowing Base Addendum shall
become a part of the Credit Agreement for all purposes.


                           ARTICLE III
                      CONDITIONS PRECEDENT
                      --------------------

     The effectiveness of this Fourth Amendment is subject to the
receipt by the Agent of the following documents, payment of any
fees due to the Agent pursuant to any agreement between the
Company and the Agent, and the satisfaction of the other
conditions provided in this Article III, each of which shall be
reasonably satisfactory to the Agent in form and substance.

     3.1  Certain Documents.  The Agent shall have received
          -----------------
multiple original counterparts, as requested by the Agent, of
each of the following:

          (a)  this Fourth Amendment, executed and delivered by a duly
     authorized officer of the Company, the Designated Subsidiaries,
     the Agent, the Co-Agent and the Required Banks;

          (b)  customary opinions of counsel of the Company in a form and
     substance acceptable to the Agent; and

          (c)  an initial Borrowing Base Certificate, substantially in the
     form of Exhibit A-1 to the Borrowing Base Addendum.

     3.2  Representations and Warranties.  Subject to the
          ------------------------------
exceptions set forth in Section 3.2 of the Third Amendment, each
of the representations and warranties made by the Borrowers in or
pursuant to the Credit Documents, including the Credit Agreement,
shall be true and correct in all material respects as of the
Amendment Effective Date, as if made on and as of such date.

                              - 5 -



<PAGE>


     3.3  No Default.  Subject to the exceptions set forth in
          ----------
Section 3.3 of the Third Amendment, no Default or Event of
Default shall have occurred and be continuing as of the Amendment
Effective Date.

     3.4  No Change.  Subject to the exceptions set forth in
          ---------
Section 3.4 of the Third Amendment, no event shall have occurred
since March 31, 2000 which, in the reasonable opinion of the
Banks, could have a Material Adverse Effect.

     3.5  Due Diligence.  The Agent shall have completed review
          -------------
and analysis, satisfactory to the Agent and with the assistance
of officers and advisors of the Company, of the property to
constitute collateral under the Security Documents referred to in
Section 3.1(b), including the owner, location and net book value
of all such property.

     3.6  Amendment Fee.  Each of the Banks that is a party to
          -------------
this Fourth Amendment shall have received from or on behalf of
the Company an amendment fee equal to the result of (a) such
Bank's Commitment multiplied by (b) .1875% (.001875), which
amendment fee shall be fully earned when paid and shall be non-
refundable.

     3.7  Other Instruments or Documents.  The Agent or any Bank
          ------------------------------
or counsel to the Agent shall receive such other instruments or
documents as they may reasonably request.

                           ARTICLE IV
                 REPRESENTATIONS AND WARRANTIES
                 ------------------------------

     Each Borrower hereby represents and warrants to the Banks
that:

     4.1  Credit Documents.
          ----------------

          (a)  Subject to the exceptions set forth in
     Section 4.1(a) of the Third Amendment, as of the date of
     execution and delivery of this Fourth Amendment, all of the
     representations and warranties contained in each Credit
     Document to which such Borrower is a party are true and
     correct in all material respects as though made on and as of
     the Amendment Effective Date.

          (b)  Except to the extent arising out of circumstances
     previously disclosed to the Agent and the Banks by the
     Company in writing (including in any letter agreement among
     the Company and the Banks), after giving effect to this
     Fourth Amendment and of the Letter of Understanding and to
     the transactions and contemplated hereby and thereby, no
     Defaults exist under the Credit Documents or will exist
     under the Credit Documents.

          (c)  Musketeer hereby affirms that, as of the date of
     execution and delivery of this Fourth Amendment, all of the
     representations and warranties contained in the Parent
     Pledge Agreement to which it is a party are true and correct
     in all material respects as though made on and as of the
     Amendment Effective Date.

                              - 6 -



<PAGE>


     4.2  Corporate Authorization; No Contravention.  The
          -----------------------------------------
execution, delivery and performance by each Borrower and each
Designated Subsidiary and each Subsidiary of WGI executing any
Credit Document or this Fourth Amendment and any other Credit
Document (including such documents executed in connection with
this Fourth Amendment) to which such Person is a party:

          (a)  are within such Person's corporate power and
     authority and have been duly authorized by all necessary
     corporate action on the part of such Person, including any
     shareholder action that is required on the part of any
     shareholder of such Person;

          (b)  do not and will not contravene the terms of that
     Person's certificate of incorporation, bylaws, other
     organizational document or any amendment of any thereof;

          (c)  do not and will not conflict with, or result in
     any breach or contravention of, or the creation of any Lien
     under, any indenture, agreement, lease, instrument,
     Contractual Obligation, injunction, order, decree or
     undertaking to which such Person is a party; and

          (d)  do not and will not violate any Legal Requirement.

     4.3  Governmental Authorization.  No approval, consent,
          --------------------------
exemption , authorization, or other action by, or notice to, or
filing with, any Governmental Authority or, to the knowledge of
the Borrowers, any other Person, is necessary or required in
connection with the execution, delivery or performance of this
Fourth Amendment or its enforcement against any Borrower.

     4.4  Binding Effect.  This Fourth Amendment constitutes the
          --------------
legal, valid and binding obligation of each Borrower and
Designated Subsidiary enforceable against such Person in
accordance with its terms except as enforceability may be limited
by applicable bankruptcy, insolvency or similar laws affecting
the enforcement of creditors' rights generally or by equitable
principles relating to enforceability.

     4.5  Borrowings and Letter of Credit Obligations.  As of the
          -------------------------------------------
date of execution and delivery of this Fourth Amendment, (a) the
outstanding Borrowings are in an amount equal to $34,000,000 and
(b) the outstanding Letter of Credit Obligations are in an amount
equal to approximately $15,364,626 using current exchange rates.

                              - 7 -



<PAGE>


                            ARTICLE V
                          MISCELLANEOUS
                          -------------

     5.1  Confirmation.  The provisions of the Credit Agreement
          ------------
(as amended by this Fourth Amendment) shall remain in full force
and effect in accordance with its terms following the
effectiveness of this Fourth Amendment.

     5.2  Ratification and Affirmation of Borrowers.  Each of the
          -----------------------------------------
Borrowers hereby expressly (a) acknowledges the terms of this
Fourth Amendment, (b) ratifies and affirms its obligations under
its respective Credit Documents to which it is a party, (c)
acknowledges, renews and extends its continued liability under
its respective Credit Documents to which it is a party and (d)
agrees that its respective Credit Documents to which it is a
party remain in full force and effect with respect to the
Obligations as amended hereby.

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

     5.4  Counterparts.  This Fourth Amendment may be executed by
          ------------
one or more of the parties hereto in any number of separate
counterparts, and all of such counterparts taken together shall
be deemed to constitute one and the same instrument.

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

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

     5.7  Entire Agreement.  This Fourth Amendment, the Credit
          ----------------
Agreement, as amended hereby, the Notes, and the other Credit
Documents embody the entire agreement and understanding among the
parties herein and supersede all prior or contemporaneous
agreements and understandings of such Persons, verbal or written,
relating to the subject matter hereof except for any fee letters
and any prior arrangements made with respect to the payment by
any Borrower of (or any indemnification for) any fees, costs or
expenses payable to or incurred (or to be incurred) by or on
behalf of the Agent or the Banks.

                    [signature pages follow]

                              - 8 -



<PAGE>


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

                         BORROWERS:
                         ---------

                         WILLBROS GROUP, INC.

                         By: /s/ Melvin F. Spreitzer
                            -------------------------------------------------
                         Name:   Melvin F. Spreitzer
                              -----------------------------------------------
                         Title:  Executive Vice President
                               ----------------------------------------------


                         WILLBROS USA, INC.

                         By: /s/ Melvin F. Spreitzer
                            -------------------------------------------------
                         Name:   Melvin F. Spreitzer
                              -----------------------------------------------
                         Title:  Executive Vice President
                               ----------------------------------------------


                         WILLBROS INTERNATIONAL, INC.

                         By: /s/ Thomas B. Reilly
                            -------------------------------------------------
                         Name:   Thomas B. Reilly
                              -----------------------------------------------
                         Title:  Vice President
                               ----------------------------------------------


                         WILLBROS ENGINEERING & CONSTRUCTION
                         LIMITED

                         By: /s/ Thomas B. Reilly
                            -------------------------------------------------
                         Name:   Thomas B. Reilly
                              -----------------------------------------------
                         Title:  Vice President
                               ----------------------------------------------


                         WILLBROS WEST AFRICA, INC.

                         By: /s/ Thomas B. Reilly
                            -------------------------------------------------
                         Name:   Thomas B. Reilly
                              -----------------------------------------------
                         Title:  Vice President
                               ----------------------------------------------



                [Fourth Amendment Signature Page]



<PAGE>


                         WILLBROS (NIGERIA) LIMITED

                         By: /s/ J. K. Tillery
                            -------------------------------------------------
                         Name:   J. K. Tillery
                              -----------------------------------------------
                         Title:  Managing Director
                               ----------------------------------------------


                         THE OMAN CONSTRUCTION COMPANY, LLC

                         By: /s/ Latif A. Razek
                            -------------------------------------------------
                         Name:   Latif A. Razek
                              -----------------------------------------------
                         Title:  General Manager
                               ----------------------------------------------


                         ROGERS & PHILLIPS, INC.

                         By: /s/ William R. Phillips
                            -------------------------------------------------
                         Name:   William R. Phillips
                              -----------------------------------------------
                         Title:  President
                               ----------------------------------------------


                         CONSTRUCTORA CAMSA, C.A.

                         By: /s/ G. Patrick Riga
                            -------------------------------------------------
                         Name:   G. Patrick Riga
                              -----------------------------------------------
                         Title:  General Manager
                               ----------------------------------------------


                         WILLBROS OPERATING SERVICES, INC.

                         By: /s/ Curtis E. Simkin
                            -------------------------------------------------
                         Name:   Curtis E. Simkin
                              -----------------------------------------------
                         Title:  President
                               ----------------------------------------------


                         WILLBROS ENERGY SERVICES COMPANY

                         By: /s/ David W. Nightingale
                            -------------------------------------------------
                         Name:   David W. Nightingale
                              -----------------------------------------------
                         Title:  Vice President
                               ----------------------------------------------



                [Fourth Amendment Signature Page]



<PAGE>


                         WILLBROS MARINE ASSETS, INC.

                         By: /s/ Thomas B. Reilly
                            -------------------------------------------------
                         Name:   Thomas B. Reilly
                              -----------------------------------------------
                         Title:  Vice President
                               ----------------------------------------------


                         INTERNATIONAL PIPELINE EQUIPMENT, INC.

                         By: /s/ Thomas B. Reilly
                            -------------------------------------------------
                         Name:   Thomas B. Reilly
                              -----------------------------------------------
                         Title:  Vice President
                               ----------------------------------------------


                         WILLBROS MIDDLE EAST, INC.

                         By: /s/ Thomas B. Reilly
                            -------------------------------------------------
                         Name:   Thomas B. Reilly
                              -----------------------------------------------
                         Title:  Vice President
                               ----------------------------------------------


                         INVERSIONES CAMSA, C.A.

                         By: /s/ G. Patrick Riga
                            -------------------------------------------------
                         Name:   G. Patrick Riga
                              -----------------------------------------------
                         Title:  General Manager
                               ----------------------------------------------


                         WILLBROS ENGINEERS, INC.

                         By: /s/ James R. Beasley
                            -------------------------------------------------
                         Name:   James R. Beasley
                              -----------------------------------------------
                         Title:  President
                               ----------------------------------------------


                         "ESCA" EQUIPMENT SERVICE COMPANIA
                         ANONIMA

                         By: /s/ G. Patrick Riga
                            -------------------------------------------------
                         Name:   G. Patrick Riga
                              -----------------------------------------------
                         Title:  General Manager
                               ----------------------------------------------



                [Fourth Amendment Signature Page]



<PAGE>


                         WILLBROS INTERNATIONAL PTY LIMITED

                         By: /s/ John K. Allcorn
                            -------------------------------------------------
                         Name:   John K. Allcorn
                              -----------------------------------------------
                         Title:  Managing Director
                               ----------------------------------------------


                         WILLBROS FAR EAST, INC.

                         By: /s/ Thomas B. Reilly
                            -------------------------------------------------
                         Name:   Thomas B. Reilly
                              -----------------------------------------------
                         Title:  Vice President
                               ----------------------------------------------


                         WILLBROS SURAMERICA, S.A.

                         By: /s/ Thomas B. Reilly
                            -------------------------------------------------
                         Name:   Thomas B. Reilly
                              -----------------------------------------------
                         Title:  Vice President
                               ----------------------------------------------


                         WILLBROS (OVERSEAS) LIMITED

                         By: /s/ Arthur J. West
                            -------------------------------------------------
                         Name:   Arthur J. West
                              -----------------------------------------------
                         Title:  Managing Director
                               ----------------------------------------------


                         MUSKETEER, with respect to its
                         representations and warranties set forth
                         in Section 4.1 of this Fourth Amendment:

                         MUSKETEER OIL B.V.

                         By: /s/ illegible
                            -------------------------------------------------
                         Name:
                              -----------------------------------------------
                         Title:  Holland Intertrust Corporation B.V.
                                 Managing Director
                               ----------------------------------------------




                [Fourth Amendment Signature Page]



<PAGE>


                         AGENT AND BANK:
                         --------------

                         ABN AMRO BANK N.V.

                         By: /s/ W. Bryan Chapman
                            -------------------------------------------------
                         Name:   W. Bryan Chapman
                              -----------------------------------------------
                         Title:  Group Vice President
                               ----------------------------------------------

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


                         CO-AGENT AND BANK:
                         -----------------

                         CREDIT LYONNAIS NEW YORK BRANCH

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


                         BANKS:
                         -----

                         BANK OF AMERICA, N.A. (formerly known as
                         Boatmen's National Bank of Oklahoma)

                         By: /s/ E. Edward Brucker, III
                            -------------------------------------------------
                         Name:   E. Edward Brucker, III
                              -----------------------------------------------
                         Title:  Vice President
                               ----------------------------------------------


                         THE BANK OF NOVA SCOTIA

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


                         ARAB BANKING CORPORATION (B.S.C.)

                         By: /s/ Grant E. McDonald
                            -------------------------------------------------
                         Name:   Grant E. McDonald
                              -----------------------------------------------
                         Title:  Vice President
                               ----------------------------------------------



                [Fourth Amendment Signature Page]



<PAGE>


                         AUSTRALIA AND NEW ZEALAND BANKING GROUP
                         LTD.

                         By: /s/ Roy Marsden
                            -------------------------------------------------
                         Name:   Roy Marsden
                              -----------------------------------------------
                         Title:  Executive Vice President - The Americas
                               ----------------------------------------------


                         BANK AUSTRIA AKTIENGESELLSCHAFT - GRAND
                         CAYMAN BRANCH

                         By: /s/ Sheila A. Maher    /s/ William W. Hunter
                            -------------------------------------------------
                         Name:   Sheila A. Maher        William W. Hunter
                              -----------------------------------------------
                         Title:  Vice President         Vice President
                               ----------------------------------------------


                         BANK OF OKLAHOMA, N.A.

                         By: /s/ Kevin A. Humphrey
                            -------------------------------------------------
                         Name:   Kevin A. Humphrey
                              -----------------------------------------------
                         Title:  Vice President
                               ----------------------------------------------


                         THE BANK OF TOKYO-MITSUBISHI LTD.-
                         HOUSTON AGENCY

                         By: /s/ John W. McGhee
                            -------------------------------------------------
                         Name:   John W. McGhee
                              -----------------------------------------------
                         Title:  Vice President
                               ----------------------------------------------



                [Fourth Amendment Signature Page]




<PAGE>


      The following exhibit to the Fourth Amendment to Credit Agreement
dated as of June 30, 2000, by and among Willbros Group, Inc., certain of
its designated subsidiaries, ABN AMRO Bank N.V., Credit Lyonnais New York
Branch and certain other banks which are parties to the Credit Agreement
dated as of February 20, 1997 have been omitted, and the Registrant agrees
to furnish supplementally a copy of such omitted exhibit to the
Securities and Exchange Commission upon its request:

Exhibit A      Pricing Schedule





<PAGE>


                     BORROWING BASE ADDENDUM

     This Borrowing Base Addendum (this "Addendum") is attached
                                         --------
to and made a part of the Fourth Amendment to Credit Agreement,
dated as of August 14, 2000, and effective as of June 30, 2000,
among Willbros Group, Inc. and the Borrowers named therein, ABN
AMRO Bank N.V., Credit Lyonnais New York Branch, and the Banks
named therein (the "Fourth Amendment").  The Fourth Amendment,
                    ----------------
upon due execution, shall cause the effectiveness of this
Addendum as of the Amendment Effective Date (as defined in the
Fourth Amendment), and this Addendum shall become a part of, for
all purposes, the Credit Agreement (as defined in the Fourth
Amendment), and references to the Credit Agreement shall include
this Addendum.  Capitalized terms used but not defined in this
Addendum shall have the meanings given to such terms in the
Credit Agreement.

     1.   Borrowing Base.
          --------------

          (a)  Generally.  The "Borrowing Base" at any time,
               ---------        --------------
     determined by reference to the most recent Borrowing Base
     Certificate in effect, shall be equal to the sum (without
     duplication) of the following:  (i) 100% of Cash
     Equivalents; (ii) 70% of Net Trade Receivables; (iii) 50% of
     Revenue Accruals; (iv) 50% of Contract Cost and Recognized
     Income Not Yet Billed; and (v) 40% of Property, Plant and
     Equipment and Spare Parts; provided, that in all events, if
                                --------
     the items set forth in clauses (i) through (iv) shall
     comprise, in the aggregate, less than 50% of the Borrowing
     Base, the Borrowing Base shall be deemed to be an amount
     equal to the product of the aggregate amounts of the items
     set forth in clauses (i) through (iv) multiplied by two.

     (b)  Certain Defined Terms.
          ---------------------

          (i)  "Cash Equivalents" shall mean the sum (without
                ----------------
     duplication) of (A) 100% of (I) cash held in US Dollars and
     other currencies approved by the Agent, (II) investments in
     direct obligations of the United States of America or any
     agency thereof, (III) investments in certificates of deposit
     of maturities less than one year issued by, or time deposits
     with, commercial banks in the United States having capital
     and surplus in excess of $500,000,000, (IV) investments in
     commercial paper of maturities less than one year rated A1
     or P1 by Standard & Poor's Corporation or Moody's Investors
     Service, Inc., respectively, or any equivalent rating from
     any other rating agency satisfactory to the Agent, (V)
     investments in securities purchased by the Company under
     repurchase obligations pursuant to which arrangements are
     made with selling financial institutions (being a financial
     institution with a rating of A1 or P1 by Standard & Poor's
     Corporation or Moody's Investors Service, Inc.,
     respectively) for such financial institutions to repurchase
     such securities within 30 days from the date of purchase by
     the Company, and other similar short-term investments made
     in connection with the Company's cash management practices,
     and (VI) investments in institutional money market mutual
     funds that abide by the criteria set forth by rule 2a-7 of
     the Investment Company Act of 1940, as amended, and (B) 50%
     of the US Dollar equivalent (determined using prevailing
     exchange rates on the date of delivery of the then most
     recent Borrowing Base Certificate) of cash held in
     currencies other than in US Dollars or such currencies
     approved by the Agent; provided, that in all events, if the
                            --------
     value of the items set forth in clause (B) exceeds the
     product of the value of the items set forth in clause (A)



<PAGE>


     multiplied by three, Cash Equivalents shall be deemed to be
     an amount equal to the product of the value of the items set
     forth in clause (A) multiplied by four.

          (ii) "Net Trade Receivables" shall mean the accounts
                ---------------------
     receivable of WGI and the WGI Ownership Percentage of the
     accounts receivable of the Operating Subsidiaries and the
     Material Joint Ventures, in each case, with respect to each
     of WGI, the Operating Subsidiaries and the Material Joint
     Ventures, that is in the ordinary course of its business and
     upon which its right to receive payment is absolute and not
     contingent upon the fulfillment of any condition whatsoever.
     Net Trade Receivables shall not include:

               (A)  any account that is unpaid more than 60 days
          past the date of invoice, except for accounts of WII
          and its subsidiaries, in which case shall not include
          any account that is unpaid more than 120 days past the
          date of invoice;

               (B)  any account that arises out of a contract or
          order that, specifically by its terms, forbids or makes
          void or unenforceable any assignment by the payee to
          the Agent for the benefit of the Lenders of the account
          receivable arising with respect thereto;

               (C)  any account arising from a "sale on
          approval," "sale or return," "bill and hold,"
          "consignment," or subject to any other repurchase or
          return agreement;

               (D)  all accounts of any Customer (except for
          accounts payable by Shell Petroleum Development Company
          of Nigeria Limited and for accounts payable by Exxon
          Mobil Corporation entities in connection with the Chad-
          Cameroon project) if 20% or more of the aggregate
          dollar amount of all outstanding invoices to such
          Customer are unpaid more than 60 days (or 180 days in
          the case of WII and its subsidiaries); or

               (E)  any account on which the Agent is not or does
          not continue to be, in the Agent's sole discretion
          (which shall not be unreasonable), satisfied with the
          credit standing of the Customer of the WGI Entity in
          relation to the amount of credit extended.

          (iii)     "Revenue Accruals" shall mean revenue
                     ----------------
     accruals of WGI and the WGI Ownership Percentage of revenue
     accruals of the Operating Subsidiaries and the Material
     Joint Ventures, in each case in the ordinary course of
     business and as reflected on the balance sheet of the
     respective WGI Entity, each such balance sheet shall be
     prepared in accordance with GAAP, consistently applied.
     Revenue Accruals shall not include any revenue accrual that
     arises out of a contract or order that, specifically by its
     terms, forbids or makes void or unenforceable any assignment
     by the payee to the Agent for the benefit of the Lenders of
     the account receivable arising with respect thereto.


                              - 2 -



<PAGE>


          (iv) "Contract Cost and Recognized Income Not Yet
                -------------------------------------------
     Billed" shall mean the contract cost and recognized income
     ------
     not yet billed of WGI and the WGI Ownership Percentage of
     the contract cost and recognized income not yet billed of
     the Operating Subsidiaries and the Material Joint Ventures,
     in each case in the ordinary course of business and as
     reflected on the balance sheet of the respective WGI Entity,
     each such balance sheet shall be prepared in accordance with
     GAAP, consistently applied.  Contract Cost and Recognized
     Income Not Yet Billed shall not include any contract cost
     and recognized income that arises out of a contract or order
     that, specifically by its terms, forbids or makes void or
     unenforceable any assignment by the payee to the Agent for
     the benefit of the Lenders of the account receivable arising
     with respect thereto.

          (v)  "Property, Plant and Equipment and Spare Parts"
                ---------------------------------------------
     shall mean the net book value of those items as reflected on the
     balance sheet of WGI and the WGI Ownership Percentage of the
     value of those items as reflected on the balance sheets of
     the Operating Subsidiaries and Material Joint Ventures, in
     all cases which balance sheets shall be prepared in
     accordance with GAAP, consistently applied.

          (vi) "Operating Subsidiary" shall mean, at any time,
                --------------------
     any direct or indirect Subsidiary of the Company which at
     the end of the preceding fiscal quarter had assets equal to
     1% or more of the total consolidated assets of the Company

          (vii)     "Material Joint Venture" shall mean any
                     ----------------------
     Project Related Partnership and/or Joint Venture, other than
     a Operating Subsidiary, in which WGI or any of its
     Subsidiaries holds an equity interest or joint venture
     interest and that has assets equal to 1% or more of the
     total consolidated assets of the Company.

          (viii)    "WGI Ownership Percentage" shall mean, with
                     ------------------------
     respect to a Operating Subsidiary or Material Joint Venture,
     the percentage of the common stock, equity interest or joint
     venture interest in such Operating Subsidiary or Material
     Joint Venture owned or controlled directly or indirectly by
     WGI; provided, that with respect to entities deemed to be
     wholly-owned Subsidiaries of WII in the definition of
     "Subsidiaries" in the Credit Agreement, the WGI Ownership
     Percentage, if applicable, shall be 100%.

          (ix) "Customers" shall mean the account debtors
                ---------
     obligated on the Net Trade Receivables.

          (x)  "WGI Entity" shall mean each of WGI, the Operating
                ----------
     Subsidiaries and the Material Joint Ventures.

     2.   Limitations on Advances.  In addition to the limitations set
          -----------------------
forth in Sections 2.1(a) and 3.1(a) of the Credit Agreement, the
aggregate of the principal amounts of all Loans outstanding and
the Letter of Credit Obligations with respect to financial
Standby Letters of Credit shall not exceed the Borrowing Base at
any time.  The Agent and the Banks shall be under no obligation
to make any Loans to the Company or issue Financial Standby
Letters of Credit in excess of the limitations stated above
and in the Credit Agreement.


                              - 3 -



<PAGE>


     3.   Reporting.  In addition to any reporting requirements
          ---------
set forth in the Credit Agreement, the Company will submit the
following in form and substance satisfactory to the Agent:

          (a)  Borrowing Base Information.  Not later than 45
               --------------------------
     days after and as of the end of each month, except for
     December and January which shall be not later than 60 days
     after the end of such months, the following information
     relating to the calculation of the Borrowing Base:

               (i)  a listing, including a reasonable description
          and value, of all Cash Equivalents;

               (ii) a listing of Net Trade Receivables in excess
          of US$10,000 each (values less than $10,000 may be
          grouped together), aged from the date of invoice,
          including the name of each debtor;

               (iii)     a listing of all Revenue Accruals, in
          each case including a reasonable description and value
          and the name of each debtor;

               (iv) a listing of all Contract Cost and Income Not
          Yet Billed, including a reasonable description and
          value and the name of each debtor; and

               (v)  a listing of all Property, Plant and
          Equipment and Spare Parts, including the owner, net
          book value and location of all such property.

          (b)  Borrowing Base Certificate.  Not later than 45
               --------------------------
     days after and as of the end of each month, except for
     December and January which shall be not later than 60 days
     after the end of such months, the Company shall supply the
     Agent, in form and detail satisfactory to the Agent, a
     "Borrowing Base Certificate" in the form of Exhibit A-1
      --------------------------
     attached hereto for all purposes, executed by a Responsible
     Officer and verifying that the Company is in compliance with
     the terms and conditions of the Credit Agreement (including,
     but not limited to, this Addendum).  At the time of each
     request for a Borrowing or a financial Standby Letter of
     Credit, the Company shall supply the Agent a Borrowing Base
     Certificate updating the information required in lines 9 and
     11.

          (c)  Right to Request Field Audit.  The Agent, at any
               ----------------------------
     time upon the request of the Required Banks, shall have the
     right to conduct, or to hire a third party to conduct on
     behalf of the Agent and the Banks, in each case at the
     Company's expense, a field audit or on-site inspection of
     the properties of the Company and the Operating
     Subsidiaries; provided that the Agent may not exercise such
                   --------
     right more than once during any calendar year.


                              - 4 -



<PAGE>


     4.   Mandatory Payment.  In addition to the limitations set
          -----------------
forth in Section 2.8(a) of the Credit Agreement, if at any time
the sum of the outstanding aggregate principal amount of the
Loans and the Letter of Credit Obligations with respect to
financial Standby Letters of Credit exceeds the then effective
Borrowing Base, then the Company shall (a) on such date pay or
prepay Loans in an aggregate amount equal to such excess together
with any amount required to be paid in connection therewith
pursuant to Section 4.13 (in accordance with the terms and
provisions of the Credit Agreement, including but not limited to
Section 2.8 thereof), or (b) provide the Agent, for the benefit
of the Banks, with additional collateral acceptable to the Agent
to eliminate such Borrowing Base deficiency.






                              - 5 -



<PAGE>


                           EXHIBIT A-1
                             to the
                     BORROWING BASE ADDENDUM

               FORM OF BORROWING BASE CERTIFICATE

Dated as of             , 200  .
            ------------     --

Status as of           , 200    (except with respect to lines 9
             ----------     --
and 11, for which the status shall be as of the date of delivery
hereunder).

In accordance with the terms of the Borrowing Base Addendum made
a part of the Credit Agreement dated as of February 20, 1997, as
amended, by and among Willbros Group, Inc., the Designated
Subsidiaries, ABN AMRO Bank N.V., Credit Lyonnais New York Branch
and the Banks named therein (with all capitalized terms used
herein having the same meanings as provided in such Credit
Agreement), the Company hereby represents and warrants that the
following calculations are true, accurate and complete and
correctly set forth the components of the Borrowing Base and
other related amounts as of the appropriate date set forth above:

1.   Cash Equivalents                               $
                                                     ------------------------

2.   Net Trade Receivables                          $
                                                     ------------------------

3.   Revenue Accruals                               $
                                                     ------------------------

4.   Contract Cost and Recognized Income
     Not Yet Billed                                $
                                                     ------------------------

5.   Property, Plant and Equipment and Spare Parts  $
                                                     ------------------------

6.   (a)  100% of line 1                            $
                                                     ------------------------
     (b)  70% of line 2                             $
                                                     ------------------------
     (c)  50% of line 3                             $
                                                     ------------------------
     (d)  50% of line 4                             $
                                                     ------------------------
     (e)  40% of line 5                             $
                                                     ------------------------

7.   The sum of lines 6(a) through 6(d)             $
                                                     ------------------------

8.   The lesser of (a) two times line 7 or
     (b) the sum of lines 6(e) and 7
     (the "Borrowing Base")                         $
           --------------                            ------------------------

9.   Outstanding balance on the Loans and
     Letter of Credit Obligations with respect
     to financial Standby Letters of Credit
     as of report date                              $
                                                     ------------------------

10.  Commitments                                    $
                                                     ------------------------


                              - 6 -



<PAGE>


11.  Available for further advances
     ((a) lesser of line 8 or line 10,
     minus (b) line 9)                              $
     -----                                           ------------------------

THE COMPANY:

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










                              - 7 -