<PAGE>
                                                                    EXHIBIT 10.1


                                                                  CONFORMED COPY


                                    AMENDMENT No. 1 dated as of September 23,
                           2002 (this "Amendment"), to the Credit Agreement
                           dated as of January 25, 2001 (the "Credit
                           Agreement"), among Oil States International, Inc., a
                           Delaware corporation (the "U.S. Borrower"), PTI Group
                           Inc., a corporation amalgamated under the laws of the
                           Province of Alberta (the "Canadian Borrower" and,
                           together with the U.S. Borrower, the "Borrowers"),
                           the lenders party thereto from time to time (the
                           "Lenders"), Credit Suisse First Boston, a bank
                           organized under the laws of Switzerland, acting
                           through its New York branch ("CSFB"), as
                           administrative agent (in such capacity, the
                           "Administrative Agent") for the Lenders and as U.S.
                           collateral agent (in such capacity, the "U.S.
                           Collateral Agent") for the Lenders, and Credit Suisse
                           First Boston (formerly, "Credit Suisse First Boston
                           Canada"), a bank organized under the laws of Canada
                           ("CSFBC"), as administrative agent (in such capacity,
                           the "Canadian Administrative Agent") for the Canadian
                           Lenders, and as Canadian collateral agent (in such
                           capacity, the "Canadian Collateral Agent") for the
                           Canadian Lenders. Capitalized terms used but not
                           defined herein shall have the meanings assigned to
                           them in the Credit Agreement.

         A. Pursuant to the Credit Agreement, the Lenders and the Issuing Bank
have extended, and have agreed to extend, credit to the Borrowers.

         B. The Borrowers have informed the Administrative Agent that the U.S.
Borrower intends to consummate a highly confidential transaction (the "Proposed
Acquisition"), pursuant to which a Subsidiary of the U.S. Borrower will acquire
all the Equity Interests of certain persons.

         C. The Borrowers have also informed the Administrative Agent that the
Proposed Acquisition is likely to exceed the U.S.$25,000,000 and U.S.$75,000,000
baskets provided for in Section 6.04(i) of the Credit Agreement, but that
otherwise the Proposed Acquisition would constitute a Permitted Acquisition.

         D. The Borrowers have requested that the Required Lenders agree to
amend (a) the definition of the term "Consolidated Net Tangible Assets" and (b)
Section 6.04(i) of the Credit Agreement in order to permit the consummation of
the Proposed Acquisition, as provided herein.

         E. The Required Lenders are willing so to amend the Credit Agreement on
the terms and subject to the conditions herein contained.

         Accordingly, in consideration of the mutual agreements herein contained
and other good and valuable consideration, the receipt and sufficiency of which
are hereby acknowledged, the parties hereto agree as follows:

         SECTION 1. Amendment. (a) The definition of the term "Consolidated Net
Tangible Assets" is hereby amended by (i) deleting the period at the end
therefrom and (ii) substituting therefor the words "; provided, however, that
Consolidated Net Tangible Assets shall not be reduced by the amount of goodwill
(to the extent the aggregate amount thereof is not in excess of U.S.$55,000,000)
associated with all Permitted Acquisitions consummated after June 30, 2002
through January 25, 2004."

         (b) Section 6.04(i) of the Credit Agreement is hereby amended by (a)
deleting from clause (iv) thereof the figure "U.S.$25,000,000" and replacing
such figure with "U.S.$35,000,000" and


<PAGE>
                                                                               2

(b) deleting from clause (v) thereof the figure "U.S.$75,000,000" and replacing
such figure with "U.S.$125,000,000".

         SECTION 2. Representations and Warranties. To induce the other parties
hereto to enter into this Amendment, the Borrowers represent and warrant to each
of the Lenders, the Administrative Agents, the Issuing Bank and the Collateral
Agents that after giving effect to this Amendment, (a) the representations and
warranties set forth in Article III of the Credit Agreement and each other Loan
Document are true and correct in all material respects on and as of the date
hereof, except to the extent such representations and warranties expressly
relate to an earlier date, (b) no Default or Event of Default has occurred and
is continuing, and (c) the Proposed Acquisition constitutes a Permitted
Acquisition.

         SECTION 3. Effectiveness. This Amendment shall become effective as of
the date first written above on the date (the "Amendment Effective Date") on
which the Administrative Agent shall have received (a) counterparts of this
Amendment that, when taken together, bear the signatures of the Borrowers, the
Guarantors and the Required Lenders and (b) the Amendment Fees (as defined
below).

         SECTION 4. Amendment Fees. The Borrowers agree to pay to each Lender
that executes and delivers a copy of this Amendment to the Administrative Agent
(or its counsel) by such Lender's close of business on September 20, 2002 (the
"Return Date"), an amendment fee (the "Amendment Fee", collectively, the
"Amendment Fees") in an amount equal to 0.125% of such Lender's Commitments
(whether used or unused) as of the Return Date. The Amendment Fee shall be
payable in immediately available U.S. dollars on the Amendment Effective Date.
Once paid, the Amendment Fees shall not be refundable.

         SECTION 5. Effect of Amendment. Except as expressly set forth herein,
this Amendment shall not by implication or otherwise limit, impair, constitute a
waiver of, or otherwise affect the rights and remedies of the Lenders, the
Issuing Bank, the Collateral Agents or the Administrative Agents under the
Credit Agreement or any other Loan Document, and shall not alter, modify, amend
or in any way affect any of the terms, conditions, obligations, covenants or
agreements contained in the Credit Agreement or any other Loan Document, all of
which are ratified and affirmed in all respects and shall continue in full force
and effect. Nothing herein shall be deemed to entitle any Loan Party to a
consent to, or a waiver, amendment, modification or other change of, any of the
terms, conditions, obligations, covenants or agreements contained in the Credit
Agreement or any other Loan Document in similar or different circumstances. This
Amendment shall apply and be effective only with respect to the provisions of
the Credit Agreement specifically referred to herein. After the date hereof, any
reference to the Credit Agreement shall mean the Credit Agreement, as modified
hereby. This Amendment shall constitute a "Loan Document" for all purposes of
the Credit Agreement and the other Loan Documents.

         SECTION 6. Counterparts. This Amendment may be executed in any number
of counterparts and by different parties hereto in separate counterparts, each
of which when so executed and delivered shall be deemed an original, but all
such counterparts together shall constitute but one and the same contract.
Delivery of an executed counterpart of a signature page of this Amendment by
facsimile transmission shall be as effective as delivery of a manually executed
counterpart hereof.

         SECTION 7. Applicable Law. THIS AMENDMENT SHALL BE GOVERNED BY, AND
CONSTRUED IN ACCORDANCE WITH, THE LAWS OF THE STATE OF NEW YORK.

         SECTION 8. Headings. The headings of this Amendment are for purposes of
reference only and shall not limit or otherwise affect the meaning hereof.


<PAGE>
                                                                               3

         SECTION 9. Expenses. The Borrowers agree to reimburse the
Administrative Agents for all out-of-pocket expenses in connection with this
Amendment, including the reasonable fees, charges and disbursements of U.S.
counsel for the Administrative Agents.

         SECTION 10. Acknowledgment of Guarantors. Each of the Subsidiary
Guarantors listed on Annex I hereto and PTI Holdco Sub hereby acknowledges
receipt and notice of, and consents to the terms of, this Amendment.





<PAGE>
                                                                               4

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

                                  OIL STATES INTERNATIONAL, INC.,

                                  by   /s/ Cindy B. Taylor
                                     -------------------------------------------
                                     Name:  Cindy B. Taylor
                                     Title: Senior Vice President and
                                            Chief Financial Officer


                                  PTI GROUP INC.,

                                  by    /s/ Cindy B. Taylor
                                     -------------------------------------------
                                     Name:  Cindy B. Taylor
                                     Title: Senior Vice President and
                                            Chief Financial Officer

                                  by
                                     -------------------------------------------
                                     Name:
                                     Title:


                                  THE SUBSIDIARY GUARANTORS
                                  LISTED ON ANNEX I HERETO,

                                  by    /s/ Cindy B. Taylor
                                     -------------------------------------------
                                     Name:  Cindy B. Taylor
                                     Title: Senior Vice President and
                                            Chief Financial Officer


                                  892493 ALBERTA INC.,

                                  by     /s/ Cindy B. Taylor
                                     -------------------------------------------
                                     Name:  Cindy B. Taylor
                                     Title: Senior Vice President and
                                            Chief Financial Officer


                                  CREDIT SUISSE FIRST BOSTON,
                                  individually and as Administrative Agent,

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

                                  by    /s/ Ian W. Nalitt
                                     -------------------------------------------
                                     Name:  Ian W. Nalitt
                                     Title: Associate




<PAGE>
                                                                               5

                                  CREDIT SUISSE FIRST BOSTON,
                                  individually and as Canadian
                                  Administrative Agent,

                                  by   /s/ Alain Daoust
                                     -------------------------------------------
                                     Name:  Alain Daoust
                                     Title: Director

                                  by   /s/ Peter Chauvin
                                     -------------------------------------------
                                     Name:  Peter Chauvin
                                     Title: Vice President



<PAGE>
                                                                               6

                                  SIGNATURE PAGE TO AMENDMENT NO. 1,
                                  DATED AS OF SEPTEMBER 23, 2002,
                                  TO THE OIL STATES INTERNATIONAL, INC.
                                  CREDIT AGREEMENT DATED AS OF
                                  JANUARY 25, 2001






                                  Name of Lender: The Bank of Nova Scotia


                                  by: /s/ N. Bell
                                      ------------------------------------------
                                      Name:  N. Bell
                                      Title: Senior Manager


<PAGE>
                                                                               6

                                  SIGNATURE PAGE TO AMENDMENT NO. 1,
                                  DATED AS OF SEPTEMBER 23, 2002,
                                  TO THE OIL STATES INTERNATIONAL, INC.
                                  CREDIT AGREEMENT DATED AS OF
                                  JANUARY 25, 2001






                                  Name of Lender: The Bank of Nova Scotia


                                  by: /s/ Richard D. Lee
                                      ------------------------------------------
                                      Name:  Richard D. Lee
                                      Title: Managing Director


<PAGE>
                                                                               6

                                  SIGNATURE PAGE TO AMENDMENT NO. 1,
                                  DATED AS OF SEPTEMBER 23, 2002,
                                  TO THE OIL STATES INTERNATIONAL, INC.
                                  CREDIT AGREEMENT DATED AS OF
                                  JANUARY 25, 2001






                                  Name of Lender: Bank of Scotland


                                  by: /s/ Joseph Fratus
                                      ------------------------------------------
                                      Name:  Joseph Fratus
                                      Title: First Vice President

<PAGE>
                                                                               6

                                  SIGNATURE PAGE TO AMENDMENT NO. 1,
                                  DATED AS OF SEPTEMBER 23, 2002,
                                  TO THE OIL STATES INTERNATIONAL, INC.
                                  CREDIT AGREEMENT DATED AS OF
                                  JANUARY 25, 2001






                                  Name of Lender: Hibernia National Bank


                                  by: /s/ Stephen H. Birnbaum
                                      ------------------------------------------
                                      Name:  Stephen H. Birnbaum
                                      Title: Vice President

<PAGE>
                                                                               6

                                  SIGNATURE PAGE TO AMENDMENT NO. 1,
                                  DATED AS OF SEPTEMBER 23, 2002,
                                  TO THE OIL STATES INTERNATIONAL, INC.
                                  CREDIT AGREEMENT DATED AS OF
                                  JANUARY 25, 2001






                                  Name of Lender: Royal Bank of Canada


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

<PAGE>
                                                                               6

                                  SIGNATURE PAGE TO AMENDMENT NO. 1,
                                  DATED AS OF SEPTEMBER 23, 2002,
                                  TO THE OIL STATES INTERNATIONAL, INC.
                                  CREDIT AGREEMENT DATED AS OF
                                  JANUARY 25, 2001






                                  Name of Lender: Southwest Bank of Texas, N.A.


                                  by: /s/ Ross Bartley
                                      ------------------------------------------
                                      Name:  Ross Bartley
                                      Title: Assistant Vice President

<PAGE>
                                                                               6

                                  SIGNATURE PAGE TO AMENDMENT NO. 1,
                                  DATED AS OF SEPTEMBER 23, 2002,
                                  TO THE OIL STATES INTERNATIONAL, INC.
                                  CREDIT AGREEMENT DATED AS OF
                                  JANUARY 25, 2001






                                  Name of Lender: Wells Fargo Bank Texas, N.A.


                                  by: /s/ Lance Reynolds
                                      ------------------------------------------
                                      Name:  Lance Reynolds
                                      Title: Relationship Manager


<PAGE>

                                                                         ANNEX I

                             SUBSIDIARY GUARANTORS


U.S. Subsidiary Guarantors
--------------------------

A-Z Terminal Corporation
Barlow-Hunt, Inc.
Capstar Drilling, L.P.
Capstar Drilling GP, L.L.C.
Capstar Drilling LP, L.L.C.
Crown Camp Services Inc.
General Marine Leasing Inc.
HWC Energy Services, Inc.
HWC Holdings, Inc.
HWC Limited
Hydraulic Well Control, Inc.
Oil States Industries, Inc.
Oil States Skagit SMATCO, LLC
Sooner Holding Company
Sooner Inc.
Sooner Pipe Inc.
Specialty Rental Tools & Supply, L.P.

Canadian Subsidiary Guarantors
------------------------------

Crown Camp Services, Ltd.
Diamond Resource Services Ltd.
PTI Camp Installations Ltd.
PTI International Ltd.
Travco Industrial Housing Ltd.