Document:

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                                                                    EXHIBIT 10.1

[BANK OF AMERICA LOGO]

                                                          AMENDMENT TO DOCUMENTS
================================================================================
                  SECOND AMENDMENT TO BUSINESS LOAN AGREEMENT

This Second Amendment to Business Loan Agreement is entered into as of January
28, 2000, among Bank of America, N.A. ("Bank") and OYO Geospace Corporation
("Borrower").

                                   RECITALS
                                   --------

A.  WHEREAS, Bank and Borrower have entered into that certain Business Loan
    Agreement dated June 26, 1998, and amended on March 18, 1999 (collectively
    the "Agreement"); and

B.  WHEREAS, Borrower and Bank desire to amend certain terms and provisions of
    said Agreement as more specifically hereinafter set forth.

                                    AGREED
                                    ------

NOW, THEREFORE, in consideration of the foregoing recitals and other valuable
consideration, the receipt and sufficiency of which are hereby acknowledged,
Bank and Borrower mutually agree to amend said agreement as follows:

1.  In Paragraph 1.2 (AVAILABILITY) of the Agreement the Date "October 1, 2001"
    is substituted for the date "June 30, 2000".

2.  Section 1.6 (OFFSHORE RATE) is amended by substituting the following table
    for the table that follows the first paragraph of that section, effective
    for interest rate elections made on or after July 1, 2000;

         FUNDED DEBT TO EBITDA                                 PERCENTAGE AMOUNT
         Less than or equal to 1.00:1.00                              1.25%
         Greater than 1.00:1.00 but less than 1.50:100                1.875%
         Greater than 1.50:100                                        2.50%

3.  Section 5.5 (GUARANTIES) of the Business Loan Agreement is hereby amended by
    deleting Houston Geophysical Products, Inc. and substituting with Geospace
    Engineering Resources, Inc.

This Amendment will become effective as of the date first written above,
provided that each of the following conditions precedent have been satisfied in
a manner satisfactory to Bank:

  The Bank has received from the Borrower a duly executed original of this
  Amendment, together with a duly executed Guarantor Acknowledgment and Consent
  in the form attached hereto (the "Consent").

Except as provided in this Amendment, all of the terms and provisions of the
Agreement and the documents executed in connection therewith shall remain in
full force and effect. All references in such other documents to the Agreement
shall hereafter be deemed to be references to the Agreement as amended hereby.

<PAGE>

THIS WRITTEN AMENDMENT AND THE DOCUMENTS EXECUTED IN CONNECTION HEREWITH
REPRESENT THE FINAL AGREEMENT BETWEEN THE PARTIES AND MAY NOT BE CONTRADICTED BY
EVIDENCE OF PRIOR, CONTEMPORANEOUS, OR SUBSEQUENT ORAL AGREEMENTS OF THE
PARTIES.

IN WITNESS WHEREOF, this Amendment has been executed by the parties hereto as of
the date first written above.

BANK OF AMERICA, N.A.

By:  /s/ George M. Smith
-------------------------------------------
George M. Smith, Senior Vice President

OYO GEOSPACE CORPORATION

By:  /s/ Thomas T. McEntire
-------------------------------------------
Thomas T. McEntire, Chief Financial OfficerEXHIBIT 10.1

                        AMENDMENT AND RESTATEMENT NO. 3

     This  Amendment  and  Restatement  No.  3  dated  as of  February  2,  2000
("Agreement")  is  among  Stone  Energy  Corporation,   a  Delaware  corporation
("Borrower"), the banks party to the Credit Agreement described below ("Banks"),
and Bank of America, N.A., as Agent for the Banks ("Agent").

                                  INTRODUCTION

     A. The Borrower,  the Agent, and the Banks are parties to the Third Amended
and Restated Credit  Agreement  dated as of July 30, 1997 (the "Original  Credit
Agreement"), Amendment and Restatement No. 1 to the Credit Agreement dated as of
March 31, 1998  ("Amendment  No. 1") and Amendment and  Restatement No. 2 to the
Credit  Agreement  dated as of May 3, 1999  ("Amendment  No. 2").  The  Original
Credit  Agreement,  as amended by  Amendment  No. 1 and  Amendment  No. 2, shall
herein be referred to as the "Credit Agreement."

     B. The  Borrower  has  requested  that the  Banks  agree  to  increase  the
commitments  under the Credit  Agreement and to make certain other amendments to
the Credit Agreement.

     THEREFORE, the Borrower, the Agent, and the Banks hereby agree as follows:

     Section  1.  Definitions;  References.  Unless  otherwise  defined  in this
Agreement,  terms  used  in this  Agreement  which  are  defined  in the  Credit
Agreement  shall  have  the  meanings  assigned  to  such  terms  in the  Credit
Agreement.

     Section 2.   Amendments.

     (a) In Section 1.01:

          (i) the definition of Applicable  Margin is amended in its entirety to
     read as follows:

          "Applicable  Margin"  means,  for any day, the  following  percentages
     based upon the ratio of (a) the aggregate  outstanding  amount of Revolving
     Advances plus the Letter of Credit Exposure to (b) the Borrowing Base as of
     such day:

<TABLE>
<CAPTION>

                    Ratio of Outstanding
                    Revolving Advances to       Applicable Margin        Applicable Margin       Applicable Margin
                    Borrowing Base              Base Rate Advances       Eurodollar Advances     Commitment Fees
                    ---------------------       ------------------       -------------------     ------------------
<S>                        <C>                        <C>                       <C>                    <C>
                            <.30                       0.00%                     0.625%                 0.25%
                           >=.30                       0.00%                     0.875%                 0.25%
                           >=.60                       0.00%                     1.25%                  0.30%
                           >=.90                       0.00%                     1.50%                  0.375%
</TABLE>

          (ii) the definition of "Majority  Banks" is amended in its entirety to
     read as follows:

          "Majority Banks" means, at any time and except as provided in the last
     sentence of this  definition,  Banks  holding at least  66-2/3% of the then
     aggregate  unpaid  principal  amount of the Notes held by the Banks and the
     Letter of Credit  Exposure of the Banks at such time,  but in no event less
     than two Banks at any time when  there  are three or more  Banks;  provided
     that if no such  principal  amount or Letter  of  Credit  Exposure  is then
     outstanding,  "Majority  Banks" shall mean Banks having at least 66-2/3% of
     the aggregate  amount of the Revolving  Commitments at such time, but in no
     event less than two Banks at any time when  there are three or more  Banks.
     For any  determination  under  Section  2.02,  "66-2/3%"  in the  foregoing
     sentence shall be "85%."

          (iii) the  definition  of  "Revolving  Maturity  Date" is  amended  by
     substituting "July 30, 2005" for "July 30, 2001".

          (b)  Paragraph  (a) of Section 2.02 is amended in its entirety to read
     as follows:

               (a) The Borrowing Base as of January 26, 2000 has been set by the
          Majority Banks and acknowledged by the Borrower as $140,000,000.00.

          (c)  Paragraph  (b) of Section  2.12 is  amended  by adding  "for such
     increased  cost" at the end of the first  sentence.

          (d)  Paragraph  (c)  of  Section  6.02  is  amended  by   substituting
     "$5,000,000.00" for "$2,500,000.00".

          (e)  Paragraph  (b)  of  Section  6.04  is  amended  by   substituting
     "$3,000,000.00" for "$1,000,000.00".

          (f)  Section  6.11 is  amended  by  substituting  "$3,000,000.00"  for
     "$1,000,000.00".

          (g) Section 6.13 is amended in its entirety to read as follows:

              Section 6.13.  Current  Ratio.  The Borrower shall not permit the
          ratio of the  Borrower's  consolidated  current  assets,  plus, to the
          extent not included in current assets,  the amount of aggregate unused
          Revolving   Commitments   to  the  Borrower's   consolidated   current
          liabilities  to be less  than  1.00 to 1.00 as of the  last day of any
          fiscal quarter.

          Section 3. Increase in Revolving Commitments. The Borrower, the Agent,
     and the Banks  hereby  agree that the  Revolving  Commitments  of the Banks
     under the Credit  Agreement  shall be  modified  to reflect  the  Revolving
     Commitments for the Banks set forth on the attached Schedule 1 and upon the
     effectiveness  of this  Agreement  pursuant  to Section 5 below,  each such
     Bank's Revolving  Commitment shall be the Revolving Commitment set forth on
     the attached Schedule 1 (such Revolving Commitment being subject to further
     amendment,  reduction  or  termination  pursuant to the terms of the Credit
     Agreement).

          Section 4. Titles. Bank of America, N.A., is hereby designated as Lead
     Arranger  and  Lead  Book  Runner,   BankBoston,   N.A.  is  designated  as
     Documentation  Agent,  and Bank  One,  Louisiana,  N.A.  is  designated  as
     syndication agent, in each case under the Credit Agreement.

          Section 5. Representations and Warranties. The Borrower represents and
     warrants to the Agent and the Banks that:

          (a)  the  representations  and  warranties  set  forth  in the  Credit
     Agreement  and in the other  Credit  Documents  are true and correct in all
     material respects as of the date of this Agreement;

          (b) (i) the execution,  delivery and performance of this Agreement and
     the replacement promissory notes referred to below are within the corporate
     power and  authority  of the  Borrower  and have been  duly  authorized  by
     appropriate proceedings and (ii) each of this Agreement and the replacement
     promissory notes constitutes a legal,  valid, and binding obligation of the
     Borrower,  enforceable in accordance  with its terms,  except as limited by
     applicable bankruptcy, insolvency,  reorganization,  moratorium, or similar
     laws affecting the rights of creditors  generally and general principles of
     equity; and

          (c) as of the effectiveness of this Agreement,  no Default or Event of
     Default has occurred and is continuing.

          Section 6. Effectiveness.  This Agreement shall become effective as of
     the date of this  Agreement,  and the Credit  Agreement shall be amended as
     provided in this Agreement upon the occurrence of the following  conditions
     precedent:

          (a) the Borrower,  the Agent,  and the Banks shall have delivered duly
     and validly executed originals of this Agreement to the Agent;

          (b) the representations and warranties in this Agreement shall be true
     and correct in all material respects;

          (c) the  Borrower  shall  have  executed  and  delivered  an  original
     Revolving Note to each of the Banks whose  Commitment  increased  under the
     terms of this  Agreement  in the  maximum  principal  amount of such Bank's
     Commitment after such increase;

          (d) the  Borrower  shall have  delivered  an opinion of its counsel in
     form and substance satisfactory to the Agent and the Banks;

          (e) the Borrower  shall have  delivered a certificate of its Secretary
     or Assistant Secretary certifying its certificate of incorporation, bylaws,
     resolutions  and incumbency and in form and substance  satisfactory  to the
     Agent and the Banks; and

          (f) the Borrower shall have paid all amounts and expenses  required to
     be paid in  connection  with this  Agreement and the  amendments  evidenced
     hereby.

          Section 7. Effect on Loan Documents.

          (a) Except as amended  herein,  the  Credit  Agreement  and the Credit
     Documents remain in full force and effect as originally  executed.  Nothing
     herein  shall act as a waiver of any of the Agents' or Banks'  rights under
     the Credit  Documents,  as amended,  including the waiver of any Default or
     Event of Default, however denominated.

          (b)  This  Agreement  is a Credit  Document  for the  purposes  of the
     provisions of the other Credit  Documents.  Without limiting the foregoing,
     any  breach  of  representations,  warranties,  and  covenants  under  this
     Agreement  may  be a  Default  or  Event  of  Default  under  other  Credit
     Documents.

          Section 8.  Choice of Law.  This  Agreement  shall be  governed by and
     construed and enforced in accordance with the laws of the State of Texas.

          Section 9. Counterparts. This Agreement may be signed in any number of
     counterparts, each of which shall be an original.

         PURSUANT TO SECTION  26.02 OF THE TEXAS  BUSINESS AND COMMERCE  CODE, A
LOAN  AGREEMENT  IN WHICH THE  AMOUNT  INVOLVED  IN THE LOAN  AGREEMENT  EXCEEDS
$50,000 IN VALUE IS NOT ENFORCEABLE  UNLESS THE LOAN AGREEMENT IS IN WRITING AND
SIGNED BY THE PARTY TO BE BOUND OR THAT PARTY'S AUTHORIZED REPRESENTATIVE.

         THE RIGHTS AND  OBLIGATIONS  OF THE PARTIES TO AN AGREEMENT  SUBJECT TO
THE  PRECEDING  PARAGRAPH  SHALL BE  DETERMINED  SOLELY  FROM THE  WRITTEN  LOAN
AGREEMENT,  AND ANY PRIOR ORAL AGREEMENTS  BETWEEN THE PARTIES ARE SUPERSEDED BY
AND  MERGED  INTO THE LOAN  AGREEMENT.  THIS  WRITTEN  AGREEMENT  AND THE CREDIT
DOCUMENTS,  AS DEFINED IN THE CREDIT  AGREEMENT,  REPRESENT THE FINAL  AGREEMENT
AMONG  THE  PARTIES  AND  MAY  NOT  BE   CONTRADICTED   BY  EVIDENCE  OF  PRIOR,
CONTEMPORANEOUS, OR SUBSEQUENT ORAL AGREEMENTS OF THE PARTIES.

         THERE ARE NO UNWRITTEN ORAL AGREEMENTS AMONG THE PARTIES.

         EXECUTED as of the date first above written.

                                    BORROWER:
                                    --------
                                    STONE ENERGY CORPORATION

                              By:     /s/James H. Prince
                                 -----------------------------------------------
                              Name:      James H. Prince
                                 -----------------------------------------------
                              Title: Vice-President and Chief Financial Officer
                                 -----------------------------------------------

                              By:     /s/J. Kent Pierret
                                 -----------------------------------------------
                              Name:      J. Kent Pierret
                                 -----------------------------------------------
                              Title: Vice President and Chief Accounting Officer
                                 -----------------------------------------------

                                    AGENT:
                                    -----
                                    BANK OF AMERICA, N.A.

                              By:     /s/Paul A. Squires
                                 -----------------------------------------------
                                         Paul A. Squires
                                         Managing Director

                                    BANKS:
                                    -----

                                    BANK OF AMERICA, N.A.

                              By:     /s/Paul A. Squires
                                 -----------------------------------------------
                                         Paul A. Squires
                                         Managing Director

                                    BANKBOSTON, N.A.

                              By:     /s/Terrence Ronan
                                 -----------------------------------------------
                              Name:      Terrence Ronan
                                 -----------------------------------------------
                              Title:     Director
                                 -----------------------------------------------

                                    BANK ONE, LOUISIANA, N.A., SUCCESSOR BY
                                    MERGER TO FIRST NATIONAL BANK OF COMMERCE

                              By:     /s/Christine M. Macan
                                 -----------------------------------------------
                              Name:      Christine M. Macan
                                 -----------------------------------------------
                              Title:     Vice President
                                 -----------------------------------------------

                                    HIBERNIA NATIONAL BANK

                              By:     /s/David R. Reid
                                 -----------------------------------------------
                              Name:      David R. Reid
                                 -----------------------------------------------
                              Title:     Senior Vice President
                                 -----------------------------------------------

<PAGE>

                                   SCHEDULE 1

                                                 Revolving Commitments
                                                 ---------------------

1.       Bank of America, N.A.                       $70,000,000.00

2.       Bank One, Louisiana, N.A.,                  $60,000,000.00

3.       BankBoston, N.A.                            $50,000,000.00

4.       Hibernia National Bank                      $20,000,000.00
                                                     --------------
                                                     $200,000,000

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