<PAGE>
 











                   ITEM 6. EXHIBITS AND REPORTS ON FORM 8-K


             1.3. PLEDGE AGREEMENT DATED DECEMBER 20, 1996 BETWEEN
                 UNIVERSAL SEISMIC ASSOCIATES, INC. AND RIMCO.
<PAGE>
 


                               PLEDGE AGREEMENT

        THIS PLEDGE AGREEMENT (this "AGREEMENT") dated December 20, 1996 is made
by UNIVERSAL SEISMIC ASSOCIATES, INC., a Delaware corporation ("USA"), with an 
office at 16420 Park Ten Place, Houston, Texas 77084 to RIMCO PARTNERS, L.P., a 
Delaware limited partnership, RIMCO PARTNERS, L.P. II, a Delaware limited 
partnership, RIMCO PARTNERS, L.P. III,  a Delaware limited partnership, and 
RIMCO PARTNERS, L.P. IV, a Delaware limited partnership (collectively, the 
"NOTEHOLDERS"), all with an office at 600 Travis, Suite 6875, Houston, Texas 
77002.

        PRELIMINARY STATEMENT. The Noteholders have entered into a Note Purchase
Agreement dated as of December 20, 1996 (said Agreement, as it may hereafter be 
amended or otherwise modified from time to time, being the "NOTE AGREEMENT") 
with UNEXCO, INC., a Delaware corporation and wholly-owned subsidiary of USA
(the "COMPANY") whereby the Noteholders have purchased from the Company its 12%
Senior Secured General Obligation Notes in the maximum aggregate principal
amount of $4,000,000 subject in each case to the terms of the Note Agreement
(such notes, together with all substitutions, replacements, extensions,
modifications and restatements thereof, being referred to herein, collectively,
as the "NOTES").

        In connection with the Note Agreement, USA and the Noteholders have 
entered into that certain Guaranty Agreement, dated of even date herewith (as 
same may be amended from time to time being referred to herein as the "GUARANTY
AGREEMENT"), whereby, among other things, USA has unconditionally and 
irrevocably guaranteed the full and punctual payment when due, whether at stated
maturity or earlier by acceleration or otherwise, of any and all debts, 
liabilities and obligations of the Company now or hereafter existing under the 
Note Agreement, the Notes or any of the other Transaction Documents (as such 
term is defined in the Note Agreement). USA is the owner of all of the issued 
and outstanding shares of common stock of the Company (the "PLEDGED SHARES"). It
is a condition precedent to the obligation of the Noteholders to purchase and 
pay for the Notes to be sold under the Note Agreement and to make Advances under
the Notes that USA shall have made the pledge contemplated by this Agreement.

        NOW, THEREFORE, in consideration of the premises and in order to induce 
the Noteholders to purchase the Notes under the Note Agreement, USA hereby 
agrees as follows:

        SECTION 1. DEFINED TERMS AND RELATED MATTERS.

        (a) The capitalized terms used herein which are defined in the Note
     Agreement and not otherwise defined herein shall have the meanings
     specified therein.

        (b) The words "hereof", "herein" and "hereunder" and words of similar
     import when used in this Agreement shall refer to this Agreement as a whole
     and not to any particular provision of this Agreement.

                                                                    CONFIDENTIAL
                                                                      U 05271

<PAGE>
 
        (c) Unless otherwise defined herein or in the Note Agreement, the terms
     defined in Articles 8 and 9 of the Uniform Commercial Code as currently
     in effect in the State of Texas are used herein as therein defined.

        SECTION 2. GRANT OF SECURITY. USA hereby pledges to the Noteholders, and
grants to the Noteholders a security interest in, the following (the "PLEDGED 
COLLATERAL"):

        (a) the Pledged Shares and the certificates representing the Pledged
     Shares, and all dividends, cash, instruments and other property from time
     to time received, receivable or otherwise distributed in respect of or in
     exchange for any or all of the Pledged Shares;

        (b) all additional shares of stock of the Company from time to time
     acquired by USA in any manner, and the certificates representing such
     additional shares, and all dividends, cash, instruments and other property
     from time to time received, receivable or otherwise distributed in respect
     of or in exchange for any or all of such shares; and

        (c) all proceeds of any of the foregoing.

        This inclusion of proceeds in this Agreement does not authorize USA to 
sell, dispose of or otherwise use the Pledged Collateral in any manner not 
specifically authorized hereby.

        SECTION 3. SECURITY FOR OBLIGATIONS.  This Agreement secures the prompt 
and complete (a) payment of all obligations of USA to the Noteholders now or 
hereafter existing under the Guaranty Agreement or the other Transaction 
Documents (including, without limitation, any interest accruing after the 
filing of any petition or pleading in a bankruptcy or similar proceeding), and 
(b) performance and observance by USA of all obligations, covenants and 
conditions contained in the Guaranty Agreement and the other Transaction 
Documents (including, without limitation, the obligations, covenants and 
conditions contained herein), whether for principal, interest, fees, expenses or
otherwise (all such obligations, covenants and conditions described in the 
foregoing clauses (a) and (b) being hereinafter collectively referred to as the 
"OBLIGATIONS").

        SECTION 4. DELIVERY OF PLEDGED COLLATERAL. All certificates representing
the Pledged Collateral shall be delivered to and held by or on behalf of the 
Noteholders pursuant hereto and shall be in suitable form for transfer by 
delivery, duly endorsed in blank without restriction, or shall be accompanied by
duly executed instruments of transfer or assignment in blank, all in form and 
substance satisfactory to the Noteholders. The Noteholders shall have the right,
at any time in their sole discretion and without notice to USA, to transfer to 
or to register in the names of the Noteholders any or all of the Pledged 
Collateral, subject only to the revocable rights specified in Section 7(a) 
hereof and, prior to a foreclosure sale or other disposition of the Pledged 
Collateral, the beneficial ownership of USA. In addition, the Noteholders shall 
have the right at any time to exchange certificates representing Pledged 
Collateral for certificates of smaller or larger denominations.



                                      -2-

                                                                    CONFIDENTIAL
                                                                       U 05272


<PAGE>
 

        SECTION 5. REPRESENTATIONS AND WARRANTIES. USA represents and warrants 
as follows:

        (a) The Pledged Shares have been duly authorized and validly issued and 
are fully paid and non-assessable.

        (b) USA is the legal, record and beneficial owner of the Pledged 
Collateral free and clear of any lien, security interest, option or other charge
or encumbrance except for the security interest created by this Agreement.

        (c) The delivery of the Pledged Shares to the Noteholders pursuant to 
this Agreement creates a valid and perfected first priority security interest in
the Pledged Collateral, securing the payment of the Obligations.

        (d) No authorization, approval, or other action by, and no notice to or 
filing with, any governmental authority or regulatory body or other Person is 
required either (i) for the pledge by USA of the Pledged Collateral pursuant to 
this Agreement or for the execution, delivery or performance of this Agreement 
by USA or (ii) for the exercise by the Noteholders of the voting or other rights
provided for in this Agreement or the remedies in respect of the Pledged 
Collateral pursuant to this Agreement (except as may be required in connection 
with such disposition by laws affecting the offering and sale of securities 
generally).

        (e) The Pledged Shares constitute one hundred percent (100%) of the 
issued and outstanding shares of stock of the Company.

        SECTION 6. FURTHER ASSURANCES. USA agrees that from time to time, at the
expense of USA, USA will promptly execute and deliver all further instruments 
and documents, and take all further action, that may be necessary or desirable, 
or that the Noteholders may request, in order to perfect and protect any 
security interest granted or purported to be granted hereby or to enable the 
Noteholders to exercise and enforce their rights and remedies hereunder with 
respect to any Pledged Collateral. USA will furnish to the Noteholders from time
to time statements and schedules further identifying and describing the Pledged 
Collateral and such other reports in connection with the Pledged Collateral as 
the Noteholders may reasonably request, all in reasonable detail.

        SECTION 7. VOTING RIGHTS; DIVIDENDS; ETC. (a) So long as no Event of 
Default shall have occurred and be continuing and the Noteholders have not 
delivered the notice specified in Section 7(b):

        (i) USA shall be entitled to exercise any and all voting and other 
consensual rights pertaining to the Pledged Collateral or any part thereof for 
any purpose not inconsistent with the terms of this Agreement, the Guaranty 
Agreement or the other Transaction Documents.


                                      -3-

                                                                    CONFIDENTIAL
                                                                       U 05273


<PAGE>
 

        (ii) USA shall be entitled to receive and retain any and all dividends
     paid in respect of the Pledged Collateral to the extent, and only to the
     extent, such dividends are permitted under the Note Agreement, provided,
     however, that all (A) dividends paid or payable other than in cash in
     respect of, and instruments and other property received, receivable or
     otherwise distributed in respect of, or in exchange for, any Pledged
     Collateral, (B) dividends and other distributions paid or payable in cash
     in respect of any Pledged Collateral in connection with a partial or total
     liquidation or dissolution or in connection with a reduction of capital,
     capital surplus or paid-in-surplus, and (c) cash paid, payable or otherwise
     distributed in redemption of, or in exchange for, any Pledged Collateral,
     shall be, and shall be forthwith delivered to the Noteholders to hold as,
     Pledged Collateral and shall, if received by USA, be received in trust for
     the benefit of the Noteholders, be segregated from the other property or
     funds of USA, and be forthwith delivered to the Noteholders as Pledged
     Collateral in the same form as so received (with any necessary
     endorsement).

        (b) Upon the occurrence and during the continuance of an Event of 
Default, at the option of the Noteholders exercised in a writing sent to USA:

        (i) All rights of USA to exercise the voting and other consensual rights
     which it would otherwise be entitled to exercise pursuant to 
     Section 7(a)(i) shall cease, and the Noteholders shall thereupon have the
     sole right to exercise such voting and other consensual rights.

        (ii) All rights of USA to receive the dividends which it would otherwise
     be entitled to receive and retain pursuant to Section 7(a)(ii) shall cease,
     and the Noteholders shall thereupon have the right to receive and hold as
     Pledged Collateral such dividends.

        (iii) All dividend payments which are received by USA contrary to the
     provisions of paragraph (ii) of this Section 7(b) shall be received in
     trust for the benefit of the Noteholders, shall be segregated from other
     funds of USA and shall be forthwith paid over the Noteholders as Pledged
     Collateral in the same form as so received (with any necessary
     endorsement).

        SECTION 8. TRANSFERS AND OTHER LIENS. USA shall not: (a) sell, assign 
(by agreement, operation of law or otherwise) or otherwise dispose of, or grant 
any option with respect to, any of the Pledged Collateral; or (b) create or 
suffer to exist any Lien upon or with respect to any of the Pledged Collateral, 
except for the security interest created by this Agreement. USA agrees that it 
will cause the Company not to issue any stock or other equity securities in 
addition to or in substitution for the Pledged Shares.

        SECTION 9. NOTEHOLDERS APPOINTED ATTORNEY-IN-FACT. USA hereby 
irrevocably appoints the Noteholders USA's attorney-in-fact, with full authority
in the place and stead of USA and in the name of USA, the Noteholders or 
otherwise, from time to time while an Event of Default exists in the 
Noteholders' sole discretion, to take any action and to execute any instrument 
which the Noteholders may deem necessary or advisable to accomplish the purposes
of this Agreement,


                                      -4-

                                                                    CONFIDENTIAL
                                                                       U 05274



<PAGE>
 

including, without limitation, to receive, endorse and collect all certificates 
or instruments made payable to USA representing any dividend or other 
distribution in respect of the Pledged Collateral.

        SECTION 10. NOTEHOLDERS MAY PERFORM. If USA fails to perform any 
agreement contained herein, the Noteholders may themselves perform, or cause 
performance of, such agreement, and the reasonable expenses of the Noteholders 
incurred in connection therewith shall be payable by USA under Section 14.

        SECTION 11. THE NOTEHOLDERS' DUTIES. The powers conferred on the 
Noteholders hereunder are solely to protect their interest in the Pledged 
Collateral and shall not impose any duty upon them to exercise any such powers. 
Except for reasonable care in the custody of any Pledged Collateral in their 
possession and the accounting for moneys actually received by them hereunder, 
the Noteholders shall have no duty as to any Pledged Collateral or as to the 
taking of any necessary steps to preserve rights against prior parties or any 
other rights pertaining to any Pledged Collateral. The Noteholders shall be 
deemed to have exercised reasonable care in the custody and preservation of any 
Pledged Collateral in their possession if such Pledged Collateral is accorded 
treatment substantially equal to that which the Noteholders accord their own 
property, it being understood that the Noteholders hall not have any 
responsibility for (a) ascertaining, or taking action with respect to calls, 
conversions, exchanges or other matters relative to the Pledged Collateral, 
whether the Noteholders have knowledge of such matters, or (b) taking any 
necessary steps to preserve rights against any parties with respect to any 
Pledged Collateral.

        SECTION 12. REMEDIES. If any Event of Default shall have occurred and be
continuing:

        (a) The Noteholders may exercise in respect of the Pledged collateral,
     in addition to other rights and remedies provided for herein or otherwise
     available to them, all the rights and remedies of a secured party on
     default under the Uniform Commercial Code in effect in the State of Texas
     (as amended from time to time, the "Code") (whether or not the Code applies
     to the affected Pledged Collateral) and the Noteholders may also, without
     notice except as specified below, sell the Pledged Collateral or any part
     thereof in one or more parcels at public or private sale, at any of the
     Noteholder's offices or elsewhere, for cash, on credit or for future
     delivery, and upon such other terms as the Noteholders may deem
     commercially reasonable. USA agrees that, to the extent notice of sale
     shall be required by law, at least ten (10) days' notice to USA of the time
     and place of any public sale or the time after which any private sale is to
     be made shall constitute reasonable notification thereof. The NOteholders
     shall not be obligated to make any sale of Pledged Collateral regardless of
     notice of sale having been given. The Noteholders may adjourn any public or
     private sale from time to time by announcement at the time and place fixed
     therefor, and such sale may, without further notice, be made at the time
     and place to which it was so adjourned.

        (b) Any cash held by the Noteholders as Pledged Collateral and all cash
     proceeds received by the Noteholders in respect of any sale of, collection
     from, or other realization upon all or any part of the Pledged Collateral
     may, in the sole discretion of the Noteholders,


                                      -5-

                                                                   CONFIDENTIAL
                                                                      U 05275

        


<PAGE>
 

     
     be held by the Noteholders as collateral for, and/or then or at any time
     thereafter applied (after payment of any amounts payable to the Noteholders
     pursuant to Section 14) pro rata to and for the Noteholders in the
     following order of priority: first, to the NOteholders in proportion to the
     aggregate amount of Obligations then owing to each such Noteholder under
     the Guaranty Agreement, and second, to the Noteholders in proportion to the
     aggregate amount of all other Obligations then owing to each such
     Noteholder. Any surplus of such cash or cash proceeds held by the
     Noteholders and remaining after payment in full of all the Obligations
     shall be paid over to USA or to whomsoever may be lawfully entitled to
     receive such surplus.

        (c) All rights and remedies of the Noteholders expressed herein are in
     addition to all other rights and remedies possessed by the Noteholders in
     the Note Agreement, the Guaranty Agreement and any other agreement or
     instrument relating to the Obligations.

        SECTION 13. PRIVATE SALE OF PLEDGED COLLATERAL. USA recognizes that the
Noteholders may be unable to effect a public sale of any or all of the Pledged
Collateral by reason of certain prohibitions contained in the laws of any
jurisdiction outside the United States or in the Securities Act and applicable
state securities laws, but may instead be compelled to resort to one or more
private sales thereof to a restricted group of purchasers who will be obliged to
agree, among other things, to acquire such Pledged Collateral for their own
account for investment and not with a view to the distribution or resale
thereof. USA acknowledges and agrees that any such private sale shall be deemed
not to have been made in a commercially reasonable manner solely because the
sales price received is lower than the price that could have been obtained at a
public sale. The Noteholders shall not be under any obligation to delay a sale
of any of the Pledged Collateral for the period of time necessary to permit the
Company to register such securities under the laws of any jurisdiction outside
the United States, under the Securities Act or under any applicable state
securities laws, even if the Company would agree to do so.

        SECTION 14. INDEMNITY AND EXPENSES.

        (a) USA HEREBY INDEMNIFIES THE NOTEHOLDERS AND THE OTHER INDEMNIFIED
     PERSONS FROM AND AGAINST ANY AND ALL CLAIMS, LOSSES AND LIABILITIES GROWING
     OUT OF OR RESULTING FROM THIS AGREEMENT (INCLUDING, WITHOUT LIMITATION,
     ENFORCEMENT OF THIS AGREEMENT), EXCEPT CLAIMS, LOSSES OR LIABILITIES
     RESULTING FROM THE NOTEHOLDERS' OR OTHER INDEMNIFIED PERSONS' GROSS
     NEGLIGENCE OR WILLFUL MISCONDUCT. IT IS THE EXPRESS INTENTION OF USA THAT
     THE NOTEHOLDERS AND THE OTHER INDEMNIFIED PERSONS SHALL BE INDEMNIFIED AND
     HELD HARMLESS AGAINST ANY AND ALL LOSSES, LIABILITIES, CLAIMS,
     DEFICIENCIES, JUDGMENTS OR EXPENSES ARISING OUT OF OR RESULTING FROM THE
     ORDINARY NEGLIGENCE


                                      -6-

                                                                    CONFIDENTIAL
                                                                       U 05276



<PAGE>
 
     (WHETHER SOLE, CONCURRENT OR CONTRIBUTORY) OR STRICT LIABILITY OF THE 
     NOTEHOLDERS OR THE OTHER INDEMNIFIED PERSONS.

        (b) USA will upon receipt of an invoice pay to the Noteholders the
     amount of any and all expenses, including the reasonable fees and
     disbursement of their counsel and of any experts and agents, that the
     Noteholders may incur in connection with (i) the administration of this
     Agreement, (ii) the evaluation, appraisal, custody, preservation, use or
     operation of, or the sale of, collection from, or other realization upon,
     any of the Pledged Collateral, (iii) the exercise or enforcement of any of
     the rights of the Noteholders hereunder or (iv) the failure by USA to
     perform or observe any of the provisions hereof. USA agrees to pay interest
     on any expenses or other sums payable to the Noteholders hereunder that are
     not paid when due at a rate per annum equal to the lesser of (i) the
     Highest Lawful Rate and (ii) the Default Rate.

        SECTION 15. AMENDMENTS, ETC. No amendment or waiver of any provision of 
this Agreement, nor consent to any departure by USA herefrom, shall in any event
be effective unless the same shall be in writing and signed by the Noteholders 
and USA, and then such waiver or consent shall be effective only in the specific
instance and for the specific purpose for which given.

        SECTION 16. ADDRESSES FOR NOTICES. All notices and other communications 
provided for hereunder shall be given in the manner and at the addresses, and 
shall become effective as, specified in the Note Agreement. The address and 
telecopy number for USA shall be the same as those for USA set forth in the 
Guaranty Agreement.

        SECTION 17. WAIVER OF MARSHALING. All rights of marshaling of assets of 
USA, including any such right with respect to the Pledged Collateral, are hereby
waived by USA.

        SECTION 18. LIMITATION BY LAW. All the provisions of this Agreement are 
intended to be subject to all applicable mandatory provisions of law which may 
be controlling and to be limited to the extent necessary so that they will not 
render this Agreement invalid, unenforceable, in whole or in part, or not 
entitled to be recorded, registered or filed under the provisions of any 
applicable law.

        SECTION 19. SEPARABILITY. Should any clause, sentence, paragraph, 
subsection or Section of this Agreement be judicially declared to be invalid, 
unenforceable or void, such decision will not have the effect of invalidating or
voiding the remainder of this Agreement, and the parties hereto agree that the 
part or parts of this Agreement so held to be invalid, unenforceable or void 
will be deemed to have been stricken herefrom by the parties hereto, and the 
remainder will have the same force and effectiveness as if such stricken part or
parts had never been included herein.

        SECTION 20. CAPTIONS. The captions in this Agreement have been inserted 
for convenience only and shall be given no substantive meaning or significance 
whatever in construing the terms and provisions of this Agreement.


                                      -7-

                                                                    CONFIDENTIAL
                                                                       U 05277
<PAGE>
 
     SECTION 21. NO WAIVER; REMEDIES.  No failure on the part of the Noteholders
to exercise, and no delay in exercising, any right hereunder shall operate as a 
waiver thereof; nor shall any single or partial exercise of any right hereunder 
preclude any other or further exercise thereof or the exercise of any other 
right.  The remedies herein provided are cumulative and not exclusive of any 
remedies provided by law.

     SECTION 22. EXECUTION IN COUNTERPARTS.  This Agreement may be executed in 
any number of counterparts and by different parties hereto in separate 
counterparts, each of which when so executed shall be deemed to be an original 
and all of which taken together shall constitute but one and the same agreement.

     SECTION 23. CONTINUING SECURITY INTEREST; TRANSFER OF NOTES.  This 
Agreement shall create a continuing security interest in the Pledged Collateral 
and shall (i) remain in full force and effect until payment in full of the 
Obligations and termination of the Commitments, (ii) be binding upon USA, its 
successors and assigns and (iii) inure to the benefit of the Noteholders and 
their respective successors, transferees and assigns.  Without limiting the 
generality of the foregoing clause (iii), each Noteholder may assign or 
otherwise transfer all or a portion of any of the Notes held by it to any other 
Person, and such other Person (other than USA, the Company or their Affiliates) 
shall thereupon become vested with all the benefits in respect thereof granted 
to such Noteholder herein or otherwise.  Upon the payment in full of the 
Obligations and termination of the Commitments, the security interest granted 
hereby shall terminate and all rights to the Collateral shall revert to USA.  
Upon any such termination, USA shall be entitled to the return, upon its request
and at its expense, of such of the Pledged Collateral as shall not have been 
sold or otherwise applied against the Obligations pursuant to the terms hereof.

     SECTION 24. SECURITY INTEREST ABSOLUTE.  All rights of the Noteholders and 
security interests hereunder, and all obligations of USA hereunder, shall be 
absolute and unconditional irrespective of:

     (a)  any lack of validity or enforceability of the Guaranty Agreement or 
the other Transaction Documents unless such lack of validity and enforceability 
results from a failure of consideration;

     (b)  any change in the time, manner or place of payment, or in any other 
term of, all or any of the Obligations, or any other amendment or waiver of or 
any consent to any departure from the Guaranty Agreement or the other 
Transaction Documents;

     (c)  any exchange, release or non-perfection of any other collateral, or 
any release or amendment or waiver of or consent to departure from any 
guaranty, for all or any of the Obligations; or

     (d)  any other circumstance which might otherwise constitute a defense 
available to, or a discharge of, the Company or USA.

                                      -8-
                                                                    CONFIDENTIAL
                                                                      U 05278
<PAGE>
 
     SECTION 25. SURVIVAL OF REPRESENTATIONS AND WARRANTIES.  All 
representations and warranties contained in this Agreement or made in writing by
or on behalf of USA in connection herewith shall survive the execution and 
delivery of this Agreement and repayment of the Obligations.  Any investigation 
by the Noteholders shall not diminish in any respect whatsoever their rights to 
rely on such representations and warranties.

     SECTION 26. JURY WAIVER.  USA AND THE NOTEHOLDERS HEREBY IRREVOCABLY WAIVE 
ANY AND ALL RIGHT TO TRIAL BY JURY IN ANY LEGAL PROCEEDING ARISING OUT OF OR 
RELATING TO THIS AGREEMENT OR THE TRANSACTIONS CONTEMPLATED HEREBY.

     SECTION 27. CHOICE OF FORUM.  USA AND THE NOTEHOLDERS AGREE THAT ANY LEGAL 
PROCEEDING ARISING OUT OF OR RELATING TO THIS AGREEMENT OR THE TRANSACTIONS 
CONTEMPLATED HEREBY SHALL BE BROUGHT IN THE FEDERAL OR STATE COURTS OF HARRIS 
COUNTY, TEXAS.

     SECTION 28. GOVERNING LAW; TERMS.  This Agreement shall be governed by and 
construed in accordance with the laws of the State of New York, except as 
required by mandatory provisions of law and except to the extent that the 
validity or perfection of the security interest hereunder, or remedies 
hereunder, in respect of any particular Collateral are governed by the laws of a
jurisdiction other than the State of New York.

     IN WITNESS WHEREOF, USA has caused this Agreement to be duly executed and 
delivered by its duly authorized officer thereunto duly authorized as of the 
date first above written.


                                             UNIVERSAL SEISMIC ASSOCIATES, INC.


                                                    /s/ MICHAEL J. PAWELEK
                                             By: ______________________________
                                             Name:  Michael J. Pawelek
                                             Title: President

                                      -9-
                                                                    CONFIDENTIAL
                                                                      U 05279
<PAGE>
 

                            IRREVOCABLE STOCK POWER

                                                 KNOW ALL MEN BY THESE PRESENTS,

        THAT UNIVERSAL SEISMIC ASSOCIATES, INC., A DELAWARE CORPORATION ("USA"),
FOR VALUE RECEIVED has bargained, sold, assigned and transferred and by these 
presents does bargain, sell, assign and transfer unto_________________________
______________________________________________________________________________,
One Hundred (100) shares of the COMMON STOCK of UNEXCO, INC., a Delaware 
corporation (the "Corporation"), standing in the name of USA on the books of the
Corporation, represented by Certificate No. One (1) herewith, AND it does hereby
constitute and appoint ______________________________ its true and lawful 
attorney, IRREVOCABLY, for it and in its name and stead, to sell, assign, 
transfer, hypothecate, pledge and make over all or any part of the said stock 
and for that purpose to make and execute all necessary acts of assignment and 
transfer thereof, and to substitute one or more persons with like full power, 
hereby ratifying and confirming all that its said Attorney or his substitute or 
substitutes shall lawfully do by virtue hereof.

        IN WITNESS WHEREOF, I, Michael J. Pawelek, President of UNIVERSAL 
SEISMIC ASSOCIATES, INC., have hereunto set my hand and seal effective the _____
day of __________, 19__.


                                              UNIVERSAL SEISMIC ASSOCIATES, INC.



                                               By: /s/ MICHAEL J. PAWELEK
                                                   -----------------------------
                                                   Michael J. Pawelek, President






                                                                    CONFIDENTIAL
                                                                       U 05280
<PAGE>
 

                       SEE RESTRICTIONS ON REVERSE SIDE


               ORGANIZED UNDER THE LAWS OF THE STATE OF DELAWARE


NUMBER                                                                SHARES
                                                                       
  1                                                                     100

                                 UNEXCO, INC.
                                 COMMON STOCK
                 The Corporation is Authorized to Issue 1,000 
                 Shares Common Stock-Par Value $.001 Per Share

THIS CERTIFIES THAT UNIVERSAL SEISMIC ASSOCIATES, INC. is the owner of ONE 
HUNDRED (100) fully paid and non-assessable Shares 

                      of the Common Stock of UNEXCO, INC.

transferable only on the books of the Corporation by the holder hereof in person
or by duly authorized Attorney upon surrender of this Certificate properly 
endorsed.
        IN WITNESS WHEREOF, the said Corporation has caused this Certificate to 
be signed by its duly authorized officers and to be sealed with the Seal of the 
Corporation.

Dated JANUARY 18, 1996

/s/ VICKI D HUMPHREY                                    /S/ MICHAEL J.PAWELEK
---------------------                                   ----------------------
      SECRETARY                                               PRESIDENT

   VICKI D. HUMPHREY                                       MICHAEL J. PAWELEK




                                                                    CONFIDENTIAL
                                                                       U 05281
<PAGE>
 

THE SHARES REPRESENTED BY THIS CERTIFICATE HAVE NOT BEEN REGISTERED UNDER THE 
SECURITIES ACT OF 1933. THESE SHARES HAVE BEEN ACQUIRED FOR INVESTMENT AND NOT 
WITH A VIEW TO DISTRIBUTION OR RESALE, AND MAY NOT BE MORTGAGED, PLEDGED, 
HYPOTHECATED, OR OTHERWISE TRANSFERRED WITHOUT AN EFFECTIVE REGISTRATION 
STATEMENT FOR SUCH SHARES UNDER THE SECURITIES ACT OF 1933 OR AN OPINION OF 
COUNSEL FOR THE CORPORATION THAT REGISTRATION IS NOT REQUIRED UNDER SUCH ACT.

THERE ARE NO PRE-EMPTIVE RIGHTS.

CUMULATIVE VOTING IS PROHIBITED.





        The following abbreviations, when used in the inscription on the face 
of this certificate, shall be construed as though they were written out in full 
according to applicable laws or regulations. Additional abbreviations may also 
be used through not in the list.

<TABLE> 
<CAPTION> 
<S>     <C>                                                       <C> 
        TEN COM - as tenants in common                            UNIF GIFT MIN ACT - .............Custodian............(Minor)
        TEN ENT - as tenants by the entireties                       under Uniform Gifts to Minors Act..................(State)
        JT TEN - as joint tenants with right of survivorship
                 and not as tenants in common
                                                                                                                           
                                                                                   PLEASE INSERT SOCIAL SECURITY OR OTHER  
                                                                                       IDENTIFYING NUMBER OF ASSIGNEE      
For value received, the undersigned hereby sells, assigns and transfers unto      |______________________________________|
                                                                                  |______________________________________| 
----------------------------------------------------------------------------
         PLEASE PRINT OR TYPEWRITE NAME AND ADDRESS OF ASSIGNEE

---------------------------------------------------------------------------------------------------------------
----------------------------------------------------------------------------------------------------------Shares
represented by the within Certificate, and hereby irrevocably constitutes and appoints--------------------------
---------------------------------------------------------------------------------- Attorney to transfer the said
Shares on the books of the within-named Corporation with full power of substitution in the premises.
Dated,----------------------------
          In presence of                                  ------------------------------------------------------

NOTICE: The signature to this assignment must
correspond with the name as written upon the face
of the certificate in every particular without alteration
or enlargement, or any change whatever.
</TABLE> 


                                                                    CONFIDENTIAL
                                                                       U 05282