FIRST AMENDMENT TO RESTATED CREDIT AND SECURITY AGREEMENT


         This First  Amendment to Restated  Credit and Security  Agreement (this
"First  Amendment")  is made and entered  into as of the 14th day of  September,
1995, by and among SEITEL, INC., a Delaware corporation ("Seitel"),  SEITEL DATA
CORP., a Delaware  corporation  ("Data"),  SEITEL GEOPHYSICAL,  INC., a Delaware
corporation  ("Geophysical"),  SEITEL  OFFSHORE  CORP.,  a Delaware  corporation
("Offshore"), and EXSOL, INC., a Delaware corporation (collectively with Seitel,
Data,  Geophysical,  and  Offshore,  "Borrowers");  BANK  ONE,  TEXAS,  NATIONAL
ASSOCIATION,   a  national  banking   association   ("Bank  One");  and  COMPASS
BANK-HOUSTON,  a Texas state chartered banking  institution  (collectively  with
Bank One, "Banks").

                              W I T N E S S E T H :

         WHEREAS,   pursuant  to  that  certain  Restated  Credit  and  Security
Agreement dated as of December 31, 1994 (the "Loan Agreement"),  Banks agreed to
make certain loans to Borrowers upon the terms and conditions therein contained;
and

         WHEREAS,  the parties  hereto  desire to modify and amend certain terms
and provisions of the Loan Agreement.

         NOW, THEREFORE,  for good and valuable  consideration,  the receipt and
sufficiency  of which are  hereby  acknowledged,  Borrowers  and Banks  agree as
follows:

         1.       Amendments to Loan Agreement.  The Loan Agreement is modified
and amended as follows:

          1.1  The  definition  assigned  to  "Tangible  Net Worth" in
               Section  1 of the  Loan  Agreement  is  deleted  in its
               entirety  and the  following  is  substituted  in place
               thereof:

                  "Tangible Net Worth" shall mean (a) Seitel's  consolidated Net
                  Worth, plus (b) the Subordinated Debt, less (c) the sum of (i)
                  any  and  all  unconsolidated  loans  and  other  advances  to
                  Affiliates,   (ii)  unconsolidated  notes,  notes  receivable,
                  accounts, accounts receivable,  inter-company receivables, and
                  other amounts owing from  Affiliates,  (iii)  treasury  stock,
                  goodwill,  trademarks,  trade  names,  franchise,  or  license
                  agreements,  patents,  and deferred charges,  (iv) any and all
                  other intangible assets, and (v) the tangible net worth of DDD
                  Energy, Inc.




<PAGE>



          1.2  The  first   sentence  of  Section  3.19  of  the  Loan
               Agreement is deleted in its entirety and the  following
               is substituted in place thereof:

                  Anything herein to the contrary notwithstanding,  no more than
                  five  separate  Loans  shall be  outstanding  at any one time,
                  with,  for purposes of this  Section,  all Floating Rate Loans
                  constituting  one Loan,  and all LIBO Rate  Loans for the same
                  Interest Period constituting one Loan.

          1.3  Section  8.1(k) of the Loan Agreement is deleted in its
               entirety  and the  following  is  substituted  in place
               thereof:

                  Permit  at any  time  on or  after  June  30,  1995,  Seitel's
                  Consolidated  Tangible Net Worth, tested as of the end of each
                  calendar  quarter,  to be less than an amount equal to (i) the
                  sum of $110,000,000.00, plus 50% of positive Net Income earned
                  in each quarter  subsequent to June 30, 1995, plus 100% of all
                  equity  raised by Seitel  subsequent  to June 30, 1995,  minus
                                                                           -----
                  (ii) 100% of all principal  payments made on the  Subordinated
                  Debt subsequent to June 30, 1995.


          1.4  Section  8.1(l) of the Loan Agreement is deleted in its
               entirety  and the  following  is  substituted  in place
               thereof:

                  Permit  Seitel or any of its  Subsidiaries  (other than to DDD
                  Energy,  Inc.) to borrow any  money,  or  otherwise  incur any
                  additional indebtedness of any kind, except for:

                    (i)     trade   credit  on  open  account  in  the
                            ordinary course of business;

                    (ii)    obligations  relating to Seitel's Guaranty
                            of DDD Energy,  Inc.'s  obligations  under
                            the DDD Credit Agreement;

                    (iii)   intercompany loans to the extent permitted
                            in   accordance   with   the   terms   and
                            provisions of Section 8.1(o);

                    (iv)    in  addition  to  indebtedness   otherwise
                            permitted in any other subsection  hereof,
                            indebtedness not to exceed  $1,000,000.00,
                            in the aggregate annually;

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                    (v)     obligations  relating to Seitel's guaranty
                            of  obligations  incurred  by DDD  Energy,
                            Inc. in the  acquisition of up to $350,000
                            worth  of  computer   work   stations  and
                            related   equipment  to  be  purchased  or
                            leased  by DDD  Energy,  Inc.  within  six
                            months after the Closing Date; and

                    (vi)    a three year  $400,000.00 loan incurred by
                            Seitel for a promotional bus, as disclosed
                            to Banks in writing.


                  Without   limiting   the   foregoing,    none   of   Borrowers
                  (individually  or  collectively)  will  obtain  any  loans  in
                  addition to the Revolving  Line and the  Geophysical  Loan (as
                  each may be amended or  refinanced)  from either Bank  without
                  the express written consent of the other Bank. Except pursuant
                  to the terms of the Seitel Geophysical Guaranty and the Seitel
                  DDD Guaranty, and except for the limited guaranty entered into
                  by Seitel in  connection  with the Opseis Eagle Lease (as such
                  term  is  defined  in  subsection  (g)  of the  definition  of
                  Permitted Liens) and other  guaranties  entered into by Seitel
                  in the ordinary course of business in favor of unrelated third
                  parties to guarantee the  contractual  obligations  (excluding
                  the  obligations  to pay or repay  borrowed  funds or  capital
                  lease  obligations)  of its  Subsidiaries,  none of  Borrowers
                  (individually   or    collectively)    shall   guarantee   any
                  indebtedness of any other Person;

          1.5  Exhibit  "B" to the Loan  Agreement  is  deleted in its
               entirety and is replaced  with the Exhibit "B" attached
               to this First Amendment.

          1.6  Exhibit  "J" to the Loan  Agreement  is  deleted in its
               entirety and is replaced  with the Exhibit "J" attached
               to this First Amendment.

        2. Lien  Continuation.  The liens and security  interests granted in the
Prior  Security  Agreements  and in  the  Loan  Agreement  are  hereby  renewed,
extended, ratified, and confirmed by the parties thereto as continuing to secure
the payment of the indebtedness evidenced by the Notes, together with all of the
other  Liabilities.  Nothing  herein shall in any manner  diminish,  impair,  or
extinguish  any of the  indebtedness  evidenced by the Notes or any of the liens
and security interests  heretofore or hereafter securing such indebtedness.  The
liens granted in the Prior Security Agreements are not waived.  Borrowers ratify
and
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<PAGE>



acknowledge  the Prior  Security  Agreements  and the Loan  Agreement (as hereby
amended) as valid, subsisting,  and enforceable and agrees that the indebtedness
evidenced by the Notes is just,  due, owing,  and unpaid,  as stated in the Loan
Agreement, and is subject to no offsets, deductions, credits, charges, or claims
of whatsoever kind or character,  and further agrees that all offsets,  credits,
charges,  and claims of  whatsoever  kind or  character  are fully  settled  and
satisfied.  To the extent of any conflict between the Notes, or any of the other
Prior Security Agreements,  and the Loan Agreement,  as amended hereby, the Loan
Agreement, as amended hereby, shall control.

        3. Defined  Terms.  Words and terms used herein which are defined in the
Loan  Agreement  are used  herein as  defined  therein,  except as  specifically
modified  by the  terms  of this  First  Amendment.  Terms  used  in this  First
Amendment  which are not  defined in the Loan  Agreement  are used  therein,  as
herein defined.

        4. NO CONTROL BY BANK.  BORROWERS AGREE AND ACKNOWLEDGE  THAT ALL OF THE
COVENANTS  AND  AGREEMENTS  PROVIDED  FOR AND MADE BY  BORROWERS  IN THIS  FIRST
AMENDMENT, THE LOAN AGREEMENT, AND IN THE OTHER LOAN DOCUMENTS ARE THE RESULT OF
EXTENSIVE AND ARMS-LENGTH  NEGOTIATIONS AMONG BORROWERS AND BANKS. BANKS' RIGHTS
AND REMEDIES  PROVIDED FOR IN THE LOAN AGREEMENT AND IN THE OTHER LOAN DOCUMENTS
ARE INTENDED TO PROVIDE BANKS WITH A RIGHT TO OVERSEE  BORROWERS'  ACTIVITIES AS
THEY RELATE TO THE LOAN TRANSACTIONS  PROVIDED FOR IN THE LOAN AGREEMENT,  WHICH
RIGHT IS BASED ON BANKS' VESTED INTEREST IN BORROWERS'  ABILITY TO PAY THE NOTES
AND PERFORM THE OTHER  LIABILITIES.  NONE OF THE  COVENANTS OR OTHER  PROVISIONS
CONTAINED  IN THE LOAN  AGREEMENT  SHALL,  OR SHALL BE DEEMED TO, GIVE BANKS THE
RIGHT OR POWER TO EXERCISE  CONTROL OVER, OR OTHERWISE  IMPAIR,  THE  DAY-TO-DAY
AFFAIRS,  OPERATIONS, AND MANAGEMENT OF BORROWERS;  PROVIDED THAT IF EITHER BANK
BECOMES THE OWNER OF ANY STOCK OF ANY ENTITY,  WHICH  ENTITY OWNS AN INTEREST IN
ANY BORROWER, WHETHER THROUGH FORECLOSURE OR OTHERWISE, BANK THEREAFTER SHALL BE
ENTITLED TO EXERCISE SUCH LEGAL RIGHTS AS IT MAY HAVE BY BEING A SHAREHOLDER  OF
SUCH ENTITY.


        5.  Representations  and Warranties.  The representations and warranties
made by Borrowers in Section 4 of the Loan  Agreement are true and correct as of
the  date  of  this  First   Amendment,   except  that,   with  respect  to  the
representation  and warranty contained in Section 4.1(aa) of the Loan Agreement,
Geophysical   has   filed   suit   against   Greenhill   Petroleum   Corporation
("Greenhill"), a former customer of Geophysical, to collect certain amounts owed
to  Geophysical by Greenhill.  Geophysical  believes this dispute will result in
Greenhill not using Geophysical's  services in the future.  Geophysical does not
believe the loss of Greenhill as a customer will have a material  adverse effect
on Geophysical's business.
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<PAGE>



         6.       Miscellaneous.
                  --------------

                 6.1  Governing  Law.  THE TERMS AND  CONDITIONS  OF THIS  FIRST
AMENDMENT  SHALL BE GOVERNED BY AND CONSTRUED IN ACCORDANCE WITH THE LAWS OF THE
STATE OF TEXAS AND OF THE UNITED STATES OF AMERICA  APPLICABLE  TO  TRANSACTIONS
WITHIN THE STATE OF TEXAS.

                 6.2  Counterparts.  This First Amendment may be executed in two
or more  counterparts,  and it shall not be necessary that the signatures of all
parties  hereto be contained on any one  counterpart  hereof.  Each  counterpart
shall be deemed an original,  but all such  counterparts  taken  together  shall
constitute one and the same instrument.

                 6.3  Preservation of the Loan Agreement. Except as specifically
modified  by the terms of this First  Amendment,  all of the terms,  provisions,
covenants,  warranties,  and agreements contained in the Loan Agreement, and all
agreements  executed in  connection  therewith,  shall  remain in full force and
effect and are hereby  restated,  affirmed,  and made again as of the  execution
date of this First Amendment.

                 6.4  Notice of Final Agreement.  THE LOAN AGREEMENT, AS
AMENDED BY THIS FIRST  AMENDMENT,  REPRESENTS  THE FINAL  AGREEMENT  BETWEEN THE
PARTIES AND MAY NOT BE  CONTRADICTED BY EVIDENCE OF PRIOR,  CONTEMPORANEOUS,  OR
SUBSEQUENT ORAL AGREEMENTS OF THE PARTIES.  THERE ARE NO ORAL AGREEMENTS BETWEEN
THE PARTIES.
                  IN WITNESS  WHEREOF,  the  parties  have  executed  this First
Amendment as of the date first above written.

                                  BORROWERS:

                                  SEITEL, INC.

                                   
                                  By:/s/ Debra D. Valice
                                     -------------------------------------------
                                     Debra D. Valice, Vice President of Finance,
                                     Chief Financial Officer, Treasurer, and
                                     Secretary


                                  SEITEL DATA CORP.


                                  By:/s/ Debra D. Valice
                                     -------------------------------------------
                                     Debra D. Valice, Secretary and Treasurer


                                  SEITEL GEOPHYSICAL, INC.


                                  By:/s/ Debra D. Valice
                                     -------------------------------------------
                                     Debra D. Valice, Secretary and Treasurer



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<PAGE>





                                    SEITEL OFFSHORE CORP.


                                    By:/s/ Debra D. Valice
                                       -----------------------------------------
                                       Debra D. Valice, Secretary and Treasurer


                                    EXSOL, INC.


                                    By:/s/ Debra D. Valice
                                       -----------------------------------------
                                       Debra D. Valice, Secretary and Treasurer


                                    BANKS:

                                    BANK ONE, TEXAS, NATIONAL
                                    ASSOCIATION


                                    By:/s/ Melanie M. Ottens
                                       -----------------------------------------
                                       Melanie M. Ottens, Vice-President


                                    COMPASS BANK - HOUSTON


                                    By:/s/ Kathleen J. Bowen
                                       -----------------------------------------
                                       Kathleen J. Bowen, Vice-President




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