<PAGE>
 
                   ITEM 6. EXHIBITS AND REPORTS ON FORM 8-K

       1.2. Amended and Restated Guaranty Agreement dated March 27, 1997
                        between the Company and RIMCO.
<PAGE>
 
                    AMENDED AND RESTATED GUARANTY AGREEMENT

     This AMENDED AND RESTATED GUARANTY AGREEMENT dated as of March 27, 1997 is 
from UNIVERSAL SEISMIC ASSOCIATES, INC. a Delaware corporation ("USA"), 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").

                             PRELIMINARY STATEMENT

     The Noteholders entered into a Note Purchase Agreement dated as of December
20, 1996 (the "Original Note Agreement") with UNEXCO, INC. (the "Company"), a 
wholly-owned subsidiary of USA, whereby the Noteholders purchased from the 
Company its 12% Senior Secured General Obligation Notes in the maximum aggregate
principal amount of $4,000,000 USA executed and delivered to the Noteholders 
that certain Guaranty Agreement dated December 20, 1996, whereby USA 
unconditionally and irrevocably guaranteed the Company's obligations under the 
Original Note Agreement (the "Original Guaranty Agreement"). The Company and the
Noteholders have entered into that certain Amended and Restated Note Purchase 
Agreement (the "Amended Note Agreement"), dated of even date herewith, whereby 
the Company and the Noteholders amended and restated the Original Note Agreement
and whereby the Noteholders purchased from the Company its Amended and Restated 
12% Senior Secured General Obligation Notes in the maximum aggregate principal 
amount of $5,500,000 (such notes, together with all substitutions, replacements,
extensions, modifications and restatements thereof, being referred to herein, 
collectively as the "Notes"), which Notes are in substitution, modification, 
renewal and increase, but not in extinguishment, novation or discharge, of the 
indebtedness evidenced by the Company's 12% Senior Secured General Obligation 
Notes issued under the Original Note Agreement. USA and the Noteholders desire 
to amend and restate the Original Guaranty Agreement to provide for USA's 
unconditional and irrevocable guarantee of the Company's obligations under the 
Amended Note Agreement and the Notes, all as more particularly set forth herein.
It is a condition precedent to the obligation of the Noteholders to make
Advances under the Amended Note Agreement that the Guarantor shall have executed
and delivered this Agreement. USA has determined that it will receive a
substantial benefit if Advances are made to the Company under the Amended Note
Agreement.

     In consideration of the premises and other good and valuable consideration,
USA and the Noteholders agree to amend and restate the Original Guaranty
Agreement as follows:
<PAGE>
 
                                   ARTICLE I
                               DEFINITIONS, ETC.

     Section 1.01. Certain Defined Terms. Capitalized terms used in this 
Agreement and not otherwise defined herein shall have the respective meanings 
set forth in the Amended Note Agreement and the Annex A attached thereto (such 
meanings to be equally applicable to both singular and plural forms of the terms
defined).

     Section 1.02. Covenant Construction. Each covenant contained herein shall 
be construed (absent express provision to the contrary) as being independent of 
each other covenant contained herein, so that compliance with any one covenant 
shall not (absent such an express contrary provision) be deemed to excuse 
compliance with any other covenant. Where any provision herein refers to action 
to be taken by any Person, or which such Person is prohibited from taking, such 
provision shall be applicable whether such action is taken directly or 
indirectly by such Person. 

     Section 1.03. Other Rules of Construction. 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. All references herein to articles, sections, annexes, exhibits and
schedules shall, unless the context requires a different construction, be deemed
to be references to the articles and sections of this Agreement and the annexes,
exhibits and schedules attached hereto and made a part hereof. In this
Agreement, unless a clear contrary intention appears, the word "including" (and
with correlative meaning "include") means including, without limiting the
generality of any description preceding such term. The headings of the various
articles and sections of this Agreement are for convenience only and shall not
affect the meaning of the terms and conditions of this Agreement. No provision
of this Agreement shall be interpreted or construed against any party solely
because that party or its legal representative drafted such provision.

                                  ARTICLE II
                                   GUARANTY

     Section 2.01. Guaranty. USA hereby unconditionally and irrevocably 
guarantees 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 Amended Note 
Agreement, the Notes or any of the other Transaction Documents whether for 
principal, interest (including, without limitation, all interest that accrues 
after the commencement of any proceeding by or against the Company under any 
bankruptcy, insolvency, liquidation, moratorium, receivership, reorganization or
other similar debtor relief law), fees, expenses or otherwise (such obligations 
being the "Obligations"), and agrees to pay any and all reasonable costs and 
expenses (including counsel fees and legal expenses) incurred by the Noteholders
in connection with the protection, defense or enforcement of any rights under 
this Agreement and any of the other Transaction Documents.

                                      -2-
<PAGE>
 
          Section 2.02.  Guaranty Absolute.  USA unconditionally guarantees that
the Obligations will be paid strictly in accordance with the terms of the
Amended Note Agreement, the Notes and the other Transaction Documents,
regardless of any law, regulation or order now or hereafter in effect in any
jurisdiction affecting any of such terms or the rights of the Noteholders with
respect thereto. The liability of USA under this Agreement shall be absolute and
unconditional irrespective of: (a) any lack of validity or enforceability of the
Amended Note Agreement, the Notes, the other Transaction Documents or any other
agreement or instrument relating thereto; (b) any change in the time, manner or
place of payment of, or in any other term of, all or any of the Obligations, or
any other amendment or waiver of or any consent to departure from the Amended
Note Agreement, the Notes or the other Transaction Documents; (c) any taking,
exchange, release or non-perfection of any collateral, or any release or
amendment or waiver of or consent to departure from any other guaranty, for all
or any of the Obligations; (d) any manner of application of collateral, or
proceeds thereof, to all or any of the Obligations, or any manner of sale or
other disposition of any collateral for all or any of the Obligations or any
other assets of the Company; (e) any change, restructuring or termination of the
corporate structure or existence of the Company; or (f) any other circumstances
which might otherwise constitute a defense available to, or a discharge of, the
Company or a guarantor.

          The obligations of USA under this Agreement shall not be subject to 
reduction, termination or other impairment by reason of any setoff, recoupment, 
counterclaim or defense or for any other reason.  This Agreement is to be in 
addition to and is not to prejudice or be prejudiced by any other securities or 
guaranties (including any guaranty signed by USA) which the Noteholders may now 
or hereafter hold from or on account of the Company and is to be binding on USA 
as a continuing security notwithstanding any payments from time to time made to 
the Noteholders or any settlement of account or disability or incapacity 
affecting USA or any other thing whatsoever.  This Agreement is a continuing 
guaranty and shall remain if full force and effect until payment in full of the 
Obligations and all other amounts payable under this Agreement.

          Section 2.03.  Waiver.  USA hereby waives promptness, diligence, 
notice of acceptance and any other notice with respect to any of the Obligations
and this Agreement and any liability to which this Agreement applies or may 
apply, and waives presentment, demand of payment, notice of intent to 
accelerate, notice of acceleration, notice of dishonor or nonpayment, and any 
requirement that the Noteholders institute suit, collection proceedings or take 
any other action to collect the Obligations including any requirement that the 
Noteholders protect, secure, perfect or insure any security interest or lien or 
any property subject thereto or exhaust any right or take any action against the
Company or any other person or entity or any collateral (it being the intention 
of the Noteholders and USA that this Agreement is to be guaranty of payment and
not of collection) or that the Company or any other person be joined in any 
action hereunder.  Notwithstanding the provisions of Section 8.13, USA hereby 
expressly waives each and every right to which it may be entitled by virtue of 
the suretyship laws of the State of Texas, including, without limitation, any 
and all rights it may have pursuant to Rule 31 or 32, Texas Rules of Civil 
Procedure, Section 17.001 of the Texas Civil Practice and Remedies Code and 
Chapter 34 of the Texas Business and Commerce Code.  USA hereby waives 
marshalling of assets and liabilities, sale in inverse order of 

                                      -3-

<PAGE>
 
alienation, notice by the Noteholders of any indebtedness or liability to which 
it applies or may apply any amounts received by the Noteholders, and of the 
creation, advancement, increase, existence, extension, renewal, rearrangement 
and/or modification of the Obligations.

     Section 2.04.  Waiver of Subrogation; Etc.  USA will not have any rights of
subrogation under this Agreement, by any payment made hereunder or otherwise, 
until such time as the Noteholders have received full payment of the 
Obligations, and all such rights are hereby waived.  If, notwithstanding the 
preceding sentence, any amount shall be paid to USA on account of subrogation 
rights at any time when all the Obligations shall not have been paid in full, 
such amount shall be held in trust for the benefit of the Noteholders and shall 
forthwith be paid to the Noteholders to be credited and applied upon the 
Obligations in accordance with the terms of the Amended Note Agreement.

     USA hereby subordinates all indebtedness owing to it from the Company to 
all indebtedness of the Company to the Noteholders, and agrees that upon the 
occurrence and continuance of an Event of Default or any event which with the 
giving of notice or lapse of time could become an Event of Default, it shall not
accept any payment on the same until payment in full of the Obligations, and 
shall in no circumstance whatsoever attempt to set off or reduce any Obligations
hereunder because of such indebtedness.  USA further subordinates any lien or 
security interest that it has or may have on any collateral or security securing
payment of the Obligations to the liens and security interest on said collateral
and security in favor of the Noteholders, but the foregoing shall in no event 
imply or be construed to imply the Noteholders' agreement or consent to the 
existence of any such security interest in favor of USA.

     Section 2.05.  Right of Set-off.  Upon the occurrence and during the 
continuance of any Event of Default the Noteholders are hereby authorized at any
time and from time to time, to the fullest extent permitted by law, to set off 
and apply any and all deposits (general or special, time or demand, provisional 
or final) at any time held and other indebtedness at any time owing by the 
Noteholders to or for the credit or the account of USA against any and all of 
the obligations of USA now or hereafter existing under this Agreement, 
irrespective of whether or not the Noteholders shall have made any demand under 
this Agreement and although such obligations may be contingent and unmatured.  
The Noteholders agrees promptly to notify USA after any such set-off and 
application, provided that the failure to give such notice shall not affect the
validity of such set-off and application. The rights of the Noteholders under
this Section are in addition to other rights and remedies (including, without
limitation, other rights of set-off) which the Noteholders may have.

     Section 2.06.  Transaction Documents.  USA acknowledges that it has full 
and complete access to the Amended Note Agreement, the Notes and all other 
instruments and documents executed by the Company, or any other Person in 
connection with the Amended Note Agreement, has fully reviewed same and is fully
aware of their contents.

     Section 2.07.  Effect of Bankruptcy Proceeding, Etc.  This Agreement shall 
continue to be effective, or be automatically reinstated, as the case may be, if
at any time payment,

                                      -4-
<PAGE>
 
in whole or in part, of any of the sums due any Noteholders pursuant to the 
terms of the Amended Note Agreement or hereunder is rescinded or must otherwise 
be restored or returned by the Noteholders upon the insolvency, bankruptcy,
dissolution, liquidation or reorganization of the Company or USA, or upon or as
a result of the appointment of a custodian, receiver, trustee or other officer
with similar powers with respect to the Company or USA or any substantial part
of their property, or otherwise, all as though such payments had not been
made. If an Event of Default shall at any time have occurred and be continuing
and declaration of such Event of Default shall at such time be prevented by
reason of the pendency against the Company of a case or proceeding under a
bankruptcy or insolvency law, USA agrees that, for purposes of this Agreement
and its obligations hereunder, the Amended Note Agreement shall be deemed to
have been declared in default with the same effect as if the Amended Note
Agreement had been declared in default in accordance with the terms thereof, and
USA shall forthwith pay the amounts specified by the Noteholders to be paid
thereunder, any interest thereon and any other amounts guaranteed hereunder
without further notice or demand.

     Section 2.08.  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 2.09.  Security.  USA's obligations under this Agreement are 
secured by the Pledge Agreement in favor of the Noteholders.

     Section 2.10.  Further Assurances.  USA hereby agrees to execute and 
deliver all such instruments and take all such action as the Noteholders may 
from time to time reasonably request in order to fully effectuate the purpose of
this Agreement.

                                  ARTICLE III


                            Intentionally Omitted.



                                  ARTICLE IV
                     REPRESENTATIONS AND WARRANTIES OF USA

     USA represents and warrants to the Noteholders that:

     Section 4.01.  Organization; Power and Authority.  USA is a corporation 
duly organized, validly existing and in good standing under the laws of the 
State of Delaware, and is duly qualified as a foreign corporation and is in good
standing in each jurisdiction in which such qualification is required by law, 
other than those jurisdictions as to which the failure to be so qualified or in 
good standing could not, individually or in the aggregate, reasonably be 
expected to  

                                      -5-
<PAGE>
 
have a Material Adverse Effect.  USA has the corporate power and authority to 
own or hold under lease the properties it purports to own or hold under lease, 
to transact the business it transacts and proposes to transact, to execute and 
deliver this Agreement and the other Transaction Documents and to perform the 
provisions hereof and thereof.

     Section 4.02.  Authorization, etc.  This Agreement and the other 
Transaction Documents to which USA is a party have been duly authorized by all
necessary corporate action on the part of USA, and this Agreement constitutes,
and upon execution and delivery thereof each other Transaction Document to which
USA is a party will constitute, a legal, valid and binding obligation of USA
enforceable against USA in accordance with its terms, except as such
enforceability may be limited by (a) applicable bankruptcy, insolvency,
reorganization, moratorium or other similar laws affecting the enforcement of
creditors' rights generally and (b) general principles of equity (regardless of
whether such enforceability is considered in a proceeding in equity or at law).

     Section 4.03.  Compliance with Laws, Other Instruments, etc.  The 
execution, delivery and performance by USA of this Agreement and the other 
Transaction Documents to which USA is a party will not (a) contravene, result in
any breach of, or constitute a default under, or result in the creation of any 
Lien in respect of any property of USA or any Subsidiary under, any indenture, 
mortgage, deed of trust, loan, purchase or credit agreement, lease, corporate 
charter or by-laws, or any other agreement or instrument to which USA or any 
Subsidiary is bound or by which USA or any Subsidiary or any of their 
respective properties may be bound or affected, (b) conflict with or result in a
breach of any of the terms, conditions or provisions of any order, judgment, 
decree, or ruling of any court, arbitrator or Governmental Authority applicable 
to USA or any Subsidiary or (c) violate any provision of any statute or other 
rule or regulation of any Governmental Authority applicable to USA or any 
Subsidiary.

     Section 4.04.  Governmental Authorizations, etc.  No consent, approval or 
authorization of, or registration, filing or declaration with, any Governmental 
Authority is required in connection with the execution, delivery or performance 
by USA of this Agreement of the other Transaction Documents.

     Section 4.05.  Subsidiaries.  Schedule 4.05 contains complete and correct 
lists of USA's Subsidiaries, showing, as to each Subsidiary, the correct name 
thereof, the jurisdiction of its organization, and the percentage of shares of 
each class of its capital stock or similar equity interests outstanding owned by
USA and each other Subsidiary.  No Subsidiary is a party to, or otherwise 
subject to any legal restriction or any agreement (other than this Agreement and
customary limitations imposed by corporate law statutes) restricting the ability
of such Subsidiary to pay dividends out of profits or make any other similar 
distributions of profits to USA or any of its Subsidiaries that owns outstanding
shares of capital stock or similar equity interests of such Subsidiary.

     Section 4.06.  Financial Statements.  The consolidated balance sheet of USA
and its Subsidiaries as at June 30, 1996, and the related consolidated 
statements of income, retained

                                      -6-
<PAGE>
 
earnings and cash flows for the 12-month period then ended, copies of which USA
has delivered to each Noteholder, fairly present in all material respects the
consolidated financial position of USA and it Subsidiaries as of such date and
the consolidated results of their operations and cash flows for such period and
have been prepared in accordance with GAAP consistently applied throughout the
periods involved except as set forth in the notes thereto (subject, in the case
of any interim financial statements, to normal year-end adjustments).

      Section 4.07.  Disclosure. This Agreement, the documents, certificates or
other writings delivered to the Noteholders by or on behalf of USA in connection
with the transactions contemplated hereby and the financial statements referred
to in Section 4.06, taken as a whole, do not contain any untrue statement of a
material fact or omit to state any material fact necessary to make the
statements therein not misleading. Except as disclosed in the financial
statements referred to in Section 4.06, since June 30, 1996, there has been no
change in the financial condition, operations, business, properties or prospects
of USA or any Subsidiary except changes that individually or in the aggregate
could not reasonably be excepted to have a Material Adverse Effect. There is no
fact known to USA that could reasonably be expected to have a Material Adverse
Effect that has not been set forth herein or in the other documents,
certificates and other writings (including the financial statements referred to
in Section 4.06) delivered to the Noteholders by or on behalf of USA
specifically for use in connection with the transactions contemplated hereby.

      Section 4.08.  Litigation. Except as disclosed in Schedule 4.08, there are
no actions, suits or proceedings pending or, to the knowledge of USA, threatened
against or affecting USA or any Subsidiary or any property of USA or any
Subsidiary in any court or before any arbitrator of any kind before or by any
Governmental Authority that, individually or in the aggregate, could reasonably
be expected to have a Material Adverse Effect.

      Section 4.09.  Observance of Agreements, Statues and Orders. Neither USA 
nor any Subsidiary is in default under any term of any agreement or instrument
to which it is a party or by which it is bound, or any order, judgement, decree
or ruling of any court, arbitrator or Governmental Authority or is in violation
of any applicable law, ordinance, rule or regulation (including without
limitation Environmental Laws) of any Governmental Authority, which default or
violation, individually or in the aggregate, could reasonably be expected to
have a Material Adverse Effect.

      Section 4.10.  Taxes. USA and its subsidiaries have filed all tax returns
that are required to have been filed in any jurisdiction, and have paid all
taxes shown to be due and payable on such returns and all other taxes and
assessments levied upon them on their properties, assets, income or franchises,
to the extent such taxes and assessments have become due and payable and before
they have become delinquent, except for any taxes and assessments (i) the amount
of which is not individually or in the aggregate Material or (ii) the amount, 
applicability of validity of which is currently being contested in good faith by
appropriate proceedings and with respect to which USA or a Subsidiary, as the
case may be, has established adequate reserves in accordance with GAAP. USA
knows of no basis for any other tax or assessment that, if imposed, could
reasonably be

                                      -7-


<PAGE>
 
expected to have a Material Adverse Effect. The charges, accruals and reserves
on the books of USA and its Subsidiaries in respect of Federal, state or other
taxes for all fiscal periods are adequate in all respects. The Federal income
tax liabilities of USA and its Subsidiaries have been determined by the Internal
Revenue Service and paid for all fiscal years up to and including the fiscal
year ended June 30, 1996.

          Section 4.11.  Title to Property. USA and its Subsidiaries have good 
and sufficient title to their respective properties that individually or in the 
aggregate are Material, including all such properties reflected in the most 
recent audited balance sheet referred to in Section 4.06 or purported to have 
been acquired by USA or any Subsidiary after said date, in each case free and 
clear of Liens other than those permitted by this Agreement. All leases that 
individually or in the aggregate are Material are valid and subsisting and are 
in full force and effect in all material respects.

          Section 4.12.  Licenses, Permits, etc. USA and its Subsidiaries own or
possess all licenses, permits, franchises, authorizations, patents, copyrights, 
service marks, trademarks and trade names, or rights thereto, that individually 
or in the aggregate are Material, without known conflict with the rights of 
others.  To the best knowledge of USA, (a) no product of USA infringes in any 
material respect any license, permit, franchise, authorization, patent, 
copyright, service mark, trademark, trade name or other right owned by any other
Person; and (b) there is no Material violation by any Person of any right of USA
or any of its Subsidiaries with respect to any patent, copyright, service mark,
trademark, trade name or other right owned or used by USA or any of its
Subsidiaries.

          Section 4.13.  Compliance with ERISA.

          (a)  USA and each ERISA Affiliate have operated and administered each 
Plan in compliance with all applicable laws except for such instances of 
noncompliance as have not resulted in and could not reasonably be expected to 
result in a Material Adverse Effect.  Neither USA nor any ERISA Affiliate has 
incurred any liability pursuant to Title I or IV of ERISA or the penalty or 
excise tax provisions of the Code relating to employee benefit plans (as defined
in section 3 of ERISA), and no event, transaction or condition has occurred or 
exists that could reasonably be expected to result in the incurrence of any such
liability by USA or any ERISA Affiliate, or in the imposition of any Lien on any
of the rights, properties or assets of USA or any ERISA Affiliate, in either
case pursuant to Title I or IV of ERISA or to such penalty or excise tax
provisions or to Section 401(a)(29) or 412 of the Code, other than such
liabilities or Liens as would not be individually or in the aggregate Material.

          (b)  The present value of the aggregate benefit liabilities under each
of the Plans (other than Multiemployer Plans), determined as of the end of such 
Plan's most recently ended plan year on the basis of the actuarial assumptions 
specified for funding purposes in such Plan's most recent actuarial valuation 
report, did not exceed the aggregate current value of the assets of such Plan 
allocable to such benefit liabilities.  The term "benefit liabilities" has the 
meaning specified in 

                                      -8-
<PAGE>
 
section 4001 of ERISA and the terms "current value" and "present value" have the
meaning specified in section 3 of ERISA.

          (c)  USA and its ERISA Affiliates have not incurred withdrawal 
liabilities (and are not subject to contingent withdrawal liabilities) under 
section 4201 or 4204 of ERISA in respect of Multiemployer Plans that 
individually or in the aggregate are Material.

          (d)  The expected post-retirement benefit obligation (determined as of
the last day of USA's most recently ended fiscal year in accordance with 
Financial Accounting Standards Board Statement No. 106, without regard to 
liabilities attributable to continuation coverage mandated by section 4980B or 
the Code) of USA and its Subsidiaries is not Material.

          Section 4.14.  Status Under Certain Statutes.  Neither USA nor any 
Subsidiary is subject to regulation under the Investment Company Act of 1940, as
amended, the Public Utility Holding Company Act of 1935, as amended, the 
Interstate Commerce Act, as amended, or the Federal Power Act, as amended.

          Section 4.15.  Capitalization.  The authorized capital stock of USA 
consists solely of 20,000,000 shares of $.0001 par common stock, of which 
5,234,109 shares are issued and outstanding.

          Section 4.16.  Environmental Matters.  Neither USA nor any Subsidiary 
has knowledge of any claim or has received any notice of any claim, and no 
proceeding has been instituted raising any claim against USA or any of its 
Subsidiaries or any of their respective real properties now or formerly owned, 
leased or operated by any of them or other assets, alleging any damage to the 
environment or violation of any Environmental Laws, except, in each case, such
as could not reasonably be expected to result in a Material Adverse Effect.
Except as otherwise disclosed to the Noteholders in writing, (a) neither USA nor
any subsidiary has knowledge of any facts which would give rise to any claim,
public or private, of violation of Environmental Laws or damage to the
environment emanating from, occurring on or in any way related to real
properties now or formerly owned, leased or operated by any of them or to other
assets or their use, except, in each case, such as could not reasonably be
expected to result in a Material Adverse Effect; (b) neither USA nor any of its
Subsidiaries has stored any Hazardous Materials on real properties now or
formerly owned, leased or operated by any of them and has not disposed of any
Hazardous Materials in a manner contrary to any Environmental Laws in each case
in any manner that could reasonably be expected to result in a Material Adverse
Effect; and (c) all buildings on all real properties now owned, leased or
operated by USA or any of its Subsidiaries are in compliance with applicable
Environmental Laws, except where failure to comply could not reasonably be
expected to result in a Material Adverse Effect.

                                      -9-
<PAGE>
 
                                   ARTICLE V
                           INFORMATION AS TO COMPANY

      Section 5.01.   Financial and Business Information. USA shall deliver to 
each of the Noteholders:

      (a)   Within 45 days after the end of each quarterly fiscal period in each
fiscal year of USA, copies of (i) a consolidated balance sheet of USA and its 
Subsidiaries as at the end of such quarter, and (ii) consolidated statements of 
income, changes in shareholders' equity and cash flows of USA and its 
Subsidiaries, for such quarter and for the portion of the fiscal year ending 
with such quarter, setting forth in each case in comparative form the figures 
for the corresponding periods in the previous fiscal year, all in reasonable 
detail, prepared in accordance with GAAP applicable to quarterly financial 
statements generally, and certified by a Senior Financial Officer of USA as 
fairly presenting, in all material respects, the financial position of the 
companies being reported on and their results of operations and cash 
flows,subject to changes resulting from year-end adjustments.

      (b)   Within 90 days after the end of each fiscal year of USA, copies of 
(i) a consolidated balance sheet of USA and its Subsidiaries, as at the end of 
such year, and (ii) consolidated statements of income, changes in shareholders' 
equity and cash flows of USA and its Subsidiaries, for such year, setting forth 
in each case in comparative form the figures for the previous fiscal year, all 
in reasonable detail, prepared in accordance with GAAP, and accompanied (A) by 
an opinion thereon of independent certified public accountants of recognized 
national standing, which opinion shall state that such financial statements 
present fairly, in all material respects, the financial position of the 
companies being reported upon and their results of operations and cash flows and
have been prepared in conformity with GAAP, and that the examination of such 
accountants in connection with such financial statements has been made in 
accordance with generally accepted auditing standards, and that such audit 
provides a reasonable basis for such opinion in the circumstances, and (B) a 
certificate of such accountants stating that they have reviewed this Agreement 
and stating further whether, in making their audit, they have become aware of 
any condition or event that then constitutes a Default or an Event of Default, 
and, if they are aware that any such condition or event then exists, specifying 
the nature and period of the existence thereof.

      (c) Within 20 days after the end of each calendar month, copies of (i) a
consolidated balance sheet of USA and its Subsidiaries as at the end of such
month, and (ii) consolidated statements of income, changes in shareholders'
equity and cash flows of USA and its Subsidiaries, for such month and for the
portion of the fiscal year ending with such month, setting forth in each case in
comparative form the figures for the corresponding periods in the previous
fiscal year, all in reasonable detail, prepared in accordance with GAAP
applicable to monthly financial statements generally, and certified by a Senior
Financial Officer of USA as fairly presenting, in all material respects, the
financial position of the companies being reported on and their results of
operations and cash flows, subject to changes resulting from year-end
adjustments.

                                     -10-
<PAGE>
 
         (d)    Promptly upon their becoming available, one copy of (i) each
financial statement, report, notice or proxy statement sent by USA or any 
Subsidiary to public securities holders generally, and (ii) each regular or 
periodic report, each registration statement (without exhibits except as 
expressly requested by such holder), and each prospectus and all amendments 
thereto filed by USA or any Subsidiary with the Securities and Exchange 
Commission and of all press releases and other statements made available 
generally by USA or any Subsidiary to the public concerning developments that 
are Material.

         (e)    Promptly, and in any event within five days after a Responsible 
Officer of USA becoming aware of any of the following, a written notice setting 
forth the nature thereof and the action, if any, that USA or an ERISA Affiliate 
proposes to take with respect thereto: (i) with respect to any Plan, any 
reportable event, as defined in section 4043(b) of ERISA and the regulations 
thereunder, for which notice thereof has not been waived pursuant to such 
regulations as in effect on the date hereof; or (ii) the taking by the PBGC of 
steps to institute, or the threatening by the PBGC of the institution of, 
proceedings under section 4042 of ERISA for the termination of, or the 
appointment of a trustee to administer, any Plan, or the receipt by USA or any
ERISA Affiliate of a notice from a Multiemployer Plan that such action has been
taken by the PBGC with respect to such Multiemployer Plan; or (iii) any event,
transaction or condition that could result in the incurrence of any liability by
USA or any ERISA Affiliate pursuant to Title I or IV of ERISA or the penalty or
excise tax provisions of the Code relating to employee benefit plans, or in the
imposition of any Lien on any of the rights, properties or assets of USA or any
ERISA Affiliate pursuant to Title I or IV of ERISA or such penalty or excise tax
provisions, if such liability or Lien, taken together with any other such
liabilities or Liens then existing, could reasonably be expected to be Material.

         (f)    Promptly, and in any event within 30 days of receipt thereof, 
copies of any notice to USA or any Subsidiary from any Federal or state 
Governmental Authority relating to any order, ruling, statute or other law or 
regulation that could reasonably be expected to have a Material Adverse Effect; 
and

         (g)    With reasonable promptness, such other data and information 
relating to the business, operations, affairs, financial condition, assets or 
properties of USA or any of its Subsidiaries or relating to the ability of USA 
to perform its obligations hereunder and under the Notes as from time to time 
may be reasonably requested by any of Noteholder.

         Section 5.02.  Officer's Certificate. Each set of financial statements 
delivered to a holder of Notes pursuant to Section 5.01(a), Section 5.01(b) or 
Section 5.01(c) shall be accompanied by a certificate of a Senior Financial 
Officer of USA setting forth: (a) the information (including detailed
calculations) required in order to establish whether USA was in compliance with
the requirements of Section 7.03 hereof during the monthly, quarterly or annual
period covered by the statements then being furnished (including with respect to
each such Section, where applicable, the calculations of the maximum or minimum
amount, ratio or percentage, as the case may be, permissible under the terms of
such Sections, and the calculation of the amount, ratio or percentage then in
existence); and (b) a statement that such officer has reviewed the relevant
terms hereof and

                                     -11-














<PAGE>
 
has made, or caused to be made, under his or her supervision, a review of the 
transactions and conditions of USA and its Subsidiaries from the beginning of 
the monthly, quarterly or annual period covered by the statements then being 
furnished to the date of the certificate and that such review shall not have 
disclosed the existence during such period of any condition or event that 
constitutes a Default or an Event of Default or, if any such condition or event 
existed or exists (including, without limitation, any such event or condition 
resulting from the failure of USA or any Subsidiary to comply with any 
Environmental Law), specifying the nature and period of existence thereof and 
what action USA shall have taken or proposes to take with respect thereto.

          Section 5.03.  Inspection. USA shall permit the representatives of 
each Noteholder, at the expense of USA and upon reasonable prior notice to USA, 
to visit and inspect any of the offices or properties of USA or any Subsidiary, 
to examine all their respective books of account, records, reports and other 
papers, to make copies and extracts therefrom, and to discuss their respective 
affairs, finances and accounts with their respective officers and independent 
public accountants (and by this provision USA authorizes said accountants to 
discuss the affairs, finances and accounts of USA and its Subsidiaries), all at 
such times and as often as may be requested.

                                  ARTICLE VI
                             AFFIRMATIVE COVENANTS

          USA covenants that so long as any of the Commitments remain if effect 
or any of the Notes are outstanding:

          Section 6.01.  Compliance with Law; Contracts. USA will, and will 
cause each of its Subsidiaries to, comply with all laws, ordinances or 
governmental rules or regulations to which each of them is subject, including, 
without limitation, Environmental Laws, and will obtain and maintain in effect 
all licenses, certificates, permits, franchises and other governmental 
authorizations necessary to the ownership of their perspective properties or to
the conduct of their respective businesses, in each case to the extent necessary
to ensure that non-compliance with such laws, ordinances or governmental rules
or regulations or failure to obtain or maintain in effect such licenses,
certificates, permits, franchises and other governmental authorizations could
not, individually or in the aggregate, reasonably be expected to have a Material
Adverse Effect. USA will, and will cause each of its Subsidiaries to, comply
with, and perform their respective obligations under, each contract or agreement
to which each is a party, unless, in the good faith judgment of USA, the failure
to so comply or perform could not reasonably be expected to have a Material
Adverse Effect.

          Section 6.02.  Insurance. USA will, and will cause each of its 
Subsidiaries to, maintain, with financially sound and reputable insurers, 
insurance with respect to their respective properties and businesses against
such casualties and contingencies, of such types, on such terms and in such
amounts (including deductibles, co-insurance and self-insurance, if adequate
reserves are maintained with respect thereto) as is customary in the case of
entities of established reputations

                                     -12-
<PAGE>
 
engaged in the same or a similar business and similarly situated, including the 
insurance described in Schedule 6.02.

     Section 6.03.  Maintenance of Properties.  USA will, and will cause each of
its Subsidiaries to, maintain and keep, or cause to be maintained and kept, 
their respective properties in good repair, working order and condition (other 
than ordinary wear and tear), so that the business carried on in connection 
therewith may be properly conducted at all times, provided that this Section 
shall not prevent USA or any Subsidiary from discontinuing the operation and the
maintenance of any of its properties if such discontinuance is desirable in the 
conduct of its business and USA has concluded that such discontinuance could 
not, individually or in the aggregate, reasonably be expected to have a Material
Adverse Effect.

     Section 6.04.  Payment of Taxes and Claims.  USA will, and will cause each 
of its Subsidiaries to, file all tax returns required to be filed in any 
jurisdiction and to pay and discharge all taxes shown to be due and payable on 
such returns and all other taxes, assessments, governmental charges, or levies 
imposed on them or any of their properties, assets, income or franchises, to the
extent such taxes and assessments have become due and payable and before they 
have become delinquent and all claims for which sums have become due and 
payable that have or might become a Lien on properties or assets of USA or any 
Subsidiary, provided that neither USA nor any Subsidiary need pay any such tax 
or assessment or claims if (i) the amount, applicability or validity thereof is 
contested by USA or such Subsidiary on a timely basis in good faith and in 
appropriate proceedings, and USA or a Subsidiary has established adequate 
reserves therefor in accordance with GAAP on the books of USA or such Subsidiary
or (ii) the nonpayment of all such taxes and assessments in the aggregate could 
not reasonably be expected to have a Material Adverse Effect.

     Section 6.05.  Corporate Existence, etc.  USA will at all times preserve 
and keep in full force and effect its corporate existence.  USA will at all 
times preserve and keep in full force and effect the corporate existence of each
of its Subsidiaries and all rights and franchises of USA and its Subsidiaries 
unless, in the good faith judgment of USA, the termination of or failure to 
preserve and keep in full force and effect such corporate existence, right or 
franchise could not, individually or in the aggregate, reasonably be expected to
have a Material Adverse Effect.

                                  ARTICLE VII
                              NEGATIVE COVENANTS

     USA covenants that so long as any of the Commitments remain in effect or 
any of the Notes are outstanding:

     Section 7.01.  Restrictions on Indebtedness.  USA will not, and will not 
permit any Subsidiary to, create, incur, assume, Guaranty or permit to exist 
any Indebtedness, except:

     (a) the Notes;

                                     -13-
<PAGE>
 
         (b)  the USA Notes;

         (c)  Indebtedness outstanding under the Fidelity Funding Agreement;

         (d)  Indebtedness with respect to the financing of insurance premiums 
     over the term in which the applicable insurance coverage is in place and
     not to exceed one year, which financing is currently conducted through AFCO
     Financing.

         Section 7.02.  Restrictions on Liens.  USA will not, and will not 
permit any Subsidiary to, create, incur, assume, or permit to exist any Lien 
with respect to any asset now owned or hereafter, except:

         (a)  Liens in favor of the Noteholders;

         (b)  Liens existing on the date hereof and described on Schedule 7.02;

         (c)  Liens in favor of the Noteholders under the USA Note Agreements;

         (d)  encumbrances consisting of easements of ingress or egress over 
     real property, where the same do not materially detract from the use or 
     enjoyment of such property by, or the value of such property to, USA;

         (e)  Liens for taxes or assessments or governmental charges or levies, 
     if payment shall not at the time required to be made in accordance with the
     provisions of Section 6.04;

         (f)  any judgment lien, unless the judgment it secures shall not, 
 within 30 days after the entry thereof, have been discharged or execution
 thereof stayed pending appeal, or shall not have been discharged within 30 days
 after the expiration of any such stay;

         (g)  statutory liens of landlords and liens of carriers, warehousemen, 
     mechanics, laborers and materialmen incurred in the ordinary course of
     business for sums not yet due or being contested in good faith; and

         (h)  Liens (other than liens created by section 4068 of ERISA) incurred
     on pledges or deposits made in the ordinary course of business in
     connection with workmen's compensation, unemployment insurance, social
     security laws or similar legislation.

         Section 7.03.  Financial Covenants.  USA will not permit:

         (a)  its Current Assets at any time to be less than the sum of (i) its 
     Current Liabilities as at such date, minus (ii) any portion of such Current
     Liabilities consisting of


                                     -14-
<PAGE>
 
  amounts outstanding under the Fidelity Funding Agreement that are not due 
  within one year of such date;

     (b) its Tangible Net Worth at any time to be less than $7,000,000; and

     (c) the sum, determined as of the last day of each calendar month, of (i) 
  its Net Income for the twelve month period then ended, plus (ii) any interest
  expense deducted in the calculation of Net Income for such twelve month
  period, plus (iii) any depreciation and amortization expense deducted in the
  calculation of Net Income for such twelve month period, plus (iv) any Federal
  income taxes deducted in the calculation of Net Income for such twelve month
  period, to be less than $2,500,000.

     Section 7.04.  Restricted Payments.  USA will not, and will not permit any 
Subsidiary, directly or indirectly, to make or pay (a) any dividend or other 
distribution on any shares of USA's capital stock (including any dividends 
payable in shares of capital stock), (b) any payment on account of the purchase,
redemption, retirement or acquisition of any shares of USA's capital stock or 
any option, warrant or other right to acquire such shares, or (c) any payments 
or other distributions to Sierra Management, Inc.

     Section 7.05.  Merger, Consolidation, etc.  USA shall not consolidate with 
or merge with any other Person or convey, transfer or lease all or substantially
all of its assets in a single transaction or series of transactions to any 
Person.

     Section 7.06.  Restrictions on Asset Sales.  USA will not, and will not 
permit any Subsidiary to, sell, transfer, assign, convey or otherwise dispose of
an interest in any asset now owned or hereafter acquired.

     Section 7.07.  Transactions with Affiliates.  USA will not, and will not 
permit any Subsidiary to, enter into directly or indirectly any Material 
transaction or Material group of related transactions (including without 
limitation the purchase, lease, sale or exchange of properties of any kind or 
the rendering of any service) with any Affiliate (other than USA or another 
Subsidiary), except in the ordinary course and pursuant to the reasonable 
requirements of USA's or such Subsidiary's business and upon fair and reasonable
terms no less favorable to USA or such Subsidiary than would be obtainable in a 
comparable arm's-length transaction with a Person not an Affiliate.

     Section 7.08.  Change in Business.  Except for oil and gas exploration and 
production operations to be conducted by the Company, USA will not, and will not
permit any of its Subsidiaries to, directly or indirectly engage to a material 
extent in any business other than those in which it is presently engaged or that
are directly related thereto, or discontinue any of its existing lines of 
business or substantially alter its method of doing business.  Without limiting 
the generality of the foregoing, USA and its Subsidiaries (other than the 
COmpany) shall not engage in any oil and gas exploration and production 
operations or business.

                                     -15-
<PAGE>
 
     Section 7.09.  Fidelity Funding Agreement.  Without the prior written 
consent of the Noteholders, USA will not, and will not permit any of its 
Subsidiaries to, amend, modify or extend the Fidelity Funding Agreement.

     Section 7.10.  Restriction on Investment.  Other than (a) the common stock 
of the Company owned by USA on the date hereof, (b) Oil and Gas Properties
transferred to the Company prior to the date hereof and (c) capital
contributions to the Company that are applied directly by the Company to pay the
Indebtedness owing on the Notes, USA will not, and will not permit any of its
Subsidiaries to, make any Investment in the Company without the Noteholders'
prior written consent.


                                 ARTICLE VIII
                                 MISCELLANEOUS

     Section 8.01.  Transaction Expenses.  Whether or not the transactions 
contemplated hereby are consummated, USA will pay all reasonable costs and 
expenses (including reasonable attorneys' fees of a special counsel and any
local or other counsel) incurred by the Noteholders or holder of a Note in
connection with such transactions and in connection with any amendments, waivers
or consents under or in respect of this Agreement or the other Transaction
Documents (whether or not such amendment, waiver or consent becomes effective),
including, without limitation: (a) the reasonable costs and expenses incurred in
enforcing or defending (or determining whether or how to enforce or defend) any
rights under this Agreement or the other Transaction Documents or in responding
to any subpoena or other legal process or informal investigative demand issued
in connection with this Agreement or the other Transaction Documents, or by
reason of being a holder of any Note, (b) the reasonable costs and expenses of
negotiation, preparation and execution of this Agreement and the other
Transaction Documents, and (c) the reasonable costs and expenses, including
reasonable financial advisors' fees, incurred in connection with the insolvency
or bankruptcy of USA or any Subsidiary or in connection with any work-out or
restructuring of the transactions contemplated hereby and by the Notes. USA will
pay, and will save the Noteholders and each other holder of a Note harmless
from, all claims in respect of any fees, costs or expenses if any, of brokers
and finders (other than those retained by the Noteholders). The obligations of
USA under this Section 8.01 will survive the payment or transfer of any Note,
the enforcement, amendment or waiver of any provision of this Agreement or the
other Transaction Documents, and the termination of this Agreement.

     Section 8.02.  Survival of Representations and Warranties.  All 
representations and warranties contained herein shall survive the execution and 
delivery of this Agreement and the Notes, the purchase or transfer by the 
Noteholders of any Note or portion thereof or interest therein and the payment 
of any Note, and may be relied upon by any subsequent holder of a Note, 
regardless of any investigation made at any time by or on behalf of the 
Noteholders or any other holder of a Note.  All statements contained in any 
certificate or other instrument delivered by or on behalf of USA pursuant to 
this Agreement shall be deemed representations and warranties of USA under this 
Agreement.

                                     -16-
<PAGE>
 
     Section 8.03. Amendment and Waiver. This Agreement may be amended, and the
observance of any term hereof may be waived (either retroactively or 
prospectively), with (and only with) the written consent of the Required 
Holders, except that no amendment or waiver may, without the written consent of 
the holder of each Note at the time outstanding affected thereby, release USA 
from its obligations hereunder. Any amendment or waiver consented to as provided
in this Section 8.03 applies equally to all holders of Notes and is binding upon
them and upon each future holder of any Note and upon USA without regard to 
whether such Note has been marked to indicate such amendment or waiver. Not such
amendment or waiver will extend to or affect any obligation, covenant or 
agreement not expressly amended or waived or impair any right consequent 
thereon. No course of dealing between USA and the holder of any Note nor any 
delay in exercising any rights hereunder or under any Note shall operate as a 
waiver of any rights of any holder of such Note.

     Section 8.04. Notices. All notices and communications provided for 
hereunder shall be in writing and sent (a) by telecopy if the sender on the same
day sends a confirming copy of such notice by a recognized overnight delivery 
service (charges prepaid), or (b) by registered or certified mail with return 
receipt requested (postage prepaid), or (c) by a recognized overnight delivery
service (with charges prepaid). Any such notice must be sent: if to a
Noteholder, to its address specified for such communications in Schedule A to
the Amended Note Agreement, or at such other address as it shall have specified
to USA in writing, if to USA, to USA at 16420 Park Ten Place, Suite 300,
Houston, Texas 77084, Telecopy No.: 713-578-7091, or at such other address as
USA shall have specified to the holder of each Note in writing. Notices under
this Section 8.04 will be deemed given only when actually received.

     Section 8.05. Limitation on Interest. Each provision in this Agreement and 
each other Transaction Document is expressly limited so that in no event 
whatsoever shall the amount paid, or otherwise agreed to be paid, by USA for the
use, forbearance or detention of the money to be loaned under this Agreement or 
any other Transaction Document or otherwise (including any sums paid as 
required by any covenant or obligation contained herein or in any other 
Transaction Document which is for the use, forbearance or detention of such 
money), exceed that amount of money which would cause the effective rate of 
interest thereon to exceed the Highest Lawful Rate, and all amounts owed under 
this Agreement and each other Transaction Document shall be held to be subject 
to reduction to the effect that such amounts so paid or agreed to be paid which 
are for the use, forbearance or detention of money under this Agreement or such 
Transaction Document shall in no event exceed that amount of money which would 
cause the effective rate of interest thereon to exceed the Highest Lawful Rate.

     Section 8.06. Successors and Assigns. All covenants and other agreements 
contained in this Agreement by or on behalf of any of the parties hereto bind 
and inure to the benefit of their respective successors and assigns (including, 
without limitation, any subsequent holder of a Note) whether so expressed or 
not.

                                     -17-
<PAGE>
 
     Section 8.07. Severability. Any provision of this Agreement that is 
prohibited or unenforceable in any jurisdiction shall, as to such jurisdiction, 
be ineffective to the extent of such prohibition or unenforceability without 
invalidating the remaining provision hereof, and any such prohibition or 
unenforceability in any jurisdiction shall (to the full extent permitted by law)
not invalidate or render unenforceable such provision in any other jurisdiction.

     Section 8.08. Counterparts. This Agreement may be executed in any number of
counterparts, each of which shall be an original but all of which together shall
constitute one instrument. Each counterpart may consist of a number of copies 
hereof, each signed by less than all, but together signed by all, of the parties
hereto.

     Section 8.09. Confidentiality. In connection with the negotiation and 
administration of this Agreement and the other Transaction Documents, USA has 
furnished and will from time to time furnish the Noteholders (such information, 
other than any such information which (i) was publicly available, or otherwise 
known to the Noteholders, at the time of disclosure, (ii) subsequently becomes 
publicly available other than through any act or omission by the Noteholders or 
(iii) otherwise subsequently becomes known to the Noteholders, being hereinafter
referred to as "Confidential Information"). The Noteholders will maintain the
confidentiality of any Confidential Information in accordance with such
procedures as the Noteholders apply generally to information of that nature. It
is understood, however, that the foregoing will not restrict the Noteholders'
ability to freely exchange such Confidential Information with current or
prospective investors, assignees and advisors. Subject to the prohibitions and
restriction imposed on the Noteholders with respect to the Confidential
Information under applicable securities laws, it is further understood that the
foregoing will not prohibit the disclosure of any or all Confidential
Information if and to the extent that such disclosure may be required or
requested (w) by a Governmental Authority, (x) pursuant to court order, subpoena
or other legal process or in connection with any pending or threatened
litigation hereunder, (y) otherwise as required by law, or (z) in order to
protect its interest or its rights or remedies hereunder or under the other
Transaction Documents; in the event of any required disclosure under clause (w),
(x), or (y) above, the Noteholders agree to use reasonable efforts to inform USA
as promptly as practicable.

     Section 8.10. Final Agreement of the Parties. THIS AGREEMENT AND THE OTHER 
TRANSACTION DOCUMENTS REPRESENT 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 UNWRITTEN ORAL AGREEMENTS BETWEEN THE 
PARTIES.
 
     Section 8.11. 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.

                                     -18-
<PAGE>
 
          Section 8.12.  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, OTHER THAN LEGAL PROCEEDINGS INSTITUTED BY THE 
NOTEHOLDERS WITH RESPECT TO THEIR RIGHTS AND REMEDIES UNDER THE SECURITY 
DOCUMENTS, WHICH PROCEEDINGS MAY BE BROUGHT IN THE FEDERAL OR STATE COURTS OF 
HARRIS COUNTY, TEXAS OR THE COURTS OF ANY OTHER JURISDICTION DEEMED APPROPRIATE 
BY THE NOTEHOLDERS TO ENFORCE THEIR RIGHTS AND REMEDIES UNDER THE SECURITY 
DOCUMENTS.

          Section 8.13.  Governing Law. This Agreement shall be construed and 
enforced in accordance with, and the rights of the parties shall be governed by,
the law of the State of New York excluding choice-of-law principles of the law 
of such State that would require the application of the laws of a jurisdiction 
other than such State.

                                     -19-
<PAGE>
 
     IN WITNESS WHEREOF, USA and the Noteholders have caused this Agreement to 
be executed by their respective representatives thereunto duly authorized 
effective as of the date first above written.

                                UNIVERSAL SEISMIC ASSOCIATES, INC.
                             
                             
                                By: /s/ Michael J. Pawelek
                                   -----------------------------------
                                Name:  Michael J. Pawelek
                                Title: President
                             
                             
                             
                                RIMCO PARTNERS, L.P.,
                                RIMCO PARTNERS, L.P. II,
                                RIMCO PARTNERS, L.P. III, and
                                RIMCO PARTNERS, L.P. IV
                             
                                By:  Resource Investors Management Company
                                     Limited Partnership, their general partner

                                By:  RIMCO Associates, Inc.,
                                     its general partner


                                By: /s/ Gary Milavec
                                   -----------------------------------
                                Name:  Gary Milavec
                                Title: Vice President

                                     -20-

<PAGE>
 
                                 SCHEDULE 4.05
                           To the Guaranty Agreement

              Subsidiaries of Universal Seismic Associates, Inc.


<TABLE> 
<CAPTION> 
                                         Jurisdiction          Percentage
Subsidiary                             of Incorporation        Ownership
----------                             ----------------        ----------
<S>                                    <C>                     <C> 
Universal Seismic Acquisition, Inc.         Texas                  100%
Universal Seismic Technologies, Inc.        Texas                  100%
Marine Automated Surveys, Inc.              Texas                  100%
Unexco, Inc.                               Delaware                100%
</TABLE> 
<PAGE>
 
                                 SCHEDULE 4.08
                           To the Guaranty Agreement

                                  Litigation

1.       No. 95-09-462; The Shamrock Pipe Line Corporation vs. Mitchell Energy
         Corporation, Universal Seismic Acquisition, Inc., Buford Drilling, Inc.
         and Marine Automated Surveys, Inc.; In the 271st Judicial District
         Court of Wise County, Texas ("Shamrock Pipe").
                                       -------------

Universal Seismic Associates, Inc. ("USA") and Marine Automated Surveys, Inc. 
("MAS") are defendants in the above action in which the plaintiffs have alleged 
that one or more of the defendants caused the plaintiffs' pipe to rupture as a 
result of negligent conduct of seismic testing, resulting in down time and lost 
gasoline. Presently USA's insurance company has assumed the defense and has 
hired counsel to represent it in the case. MAS is a wholly-owned subsidiary of 
USA which was formed for the purpose of acquiring the assets, including the 
tradename, of a now dissolved corporation. The asset acquisition occurred after 
the alleged incident giving rise to this suit. Accordingly, plaintiff's counsel 
believes that the former owner of the corporate name Marine Automated Surveys, 
now known as JBX Corporation, will be joined and that all claims with respect to
MAS will be dismissed.

2.       No. 95-12-630; Dessie Schluter, et al. v. Mitchell Energy Corp., et 
         al.; In the 271st Judicial District Court of Wise County, Texas.

This action, which arose out of the same set of facts as Shamrock Pipe, was 
                                                         -------------
brought by the owners of the real property upon which the pipeline in Shamrock 
                                                                      --------
Pipe lies for recovery of damages to such property.
----

3.       Michael T. Kanarellis, Robert J. Kecseg and the Universal Seismic
         Associates, Inc. Shareholders' Protective Committee v. Universal
         Seismic Associates, Inc., et al.; Civil Action No. 97-22 in United
         States District Court for the District of Delaware.

         This is a case brought by dissident shareholders which originally 
sought revocation of proxies submitted in favor of existing management-sponsored
members of the Board of Directors of the Company. The Directors sponsored by 
management were elected by a substantial majority of the voting shares and the 
District Court declined to overturn the result. The suit was then amended to add
claims against the Company and all of its Board members sounding in fraudulent 
misrepresentation and non-disclosure of financial information relevant to the 
Company.

4.       Universal Seismic Associates v. Michael T. Kanarellis and Robert T.
Kecseg; Cause No. 97-12684 in the 334th District Court of Harris County, Texas.

         This is a case brought against the defendants jointly for breaches of 
fiduciary duty, disclosure of confidential information and tortious interference
resulting from the defendants' disclosure of various confidential information of
the Company to the public. The defendants have not answered the suit at this 
time.


<PAGE>
 
                                 SCHEDULE 6.02

                           To the Guaranty Agreement

Schedule of Insurance
--------------------------------------------------------------------------------
<TABLE> 
<CAPTION> 
------------------------------------------------------------------------------------------------------------------------------------
   TYPE OF COVERAGE          POLICY          INSURER                        POLICY NO.      LIMITS              DEDUCTIBLE
                              DATES                                                                            
------------------------------------------------------------------------------------------------------------------------------------
<S>                        <C>         <C>                                  <C>          <C>                   <C>                 
Commercial                 4/19/95-96  Ranger Lloyds                        GL 705035    $1,000,000               $1,000 Per Claim
General Liability                                                                        Each Occurrence          Employer Benefits
                                                                                         $2,000,000                   Liability
                                                                                         General Aggregate     
------------------------------------------------------------------------------------------------------------------------------------
Business Auto Liability &  4/19/95-96  Ranger County Mutual Insurance       TBA 452156   $1,000,000               Refer to Summary
Physical Damage                        Company                                           BI/PD CSL             
                                                                                         Each Occurrence       
------------------------------------------------------------------------------------------------------------------------------------
Workers' Compensation &    4/27/95-    Insurance Company of the State       8773134(TX)  Sec A: Statutory              None
Employers' Liability       4/19/96     of Pennsylvania (AIG)                8773135(OS)  Sec B: 1,000,000      
                                                                            8773136(CA)  Maritime: 1,000,000   
                                                                                         U.S.L&H Included      
------------------------------------------------------------------------------------------------------------------------------------
Umbrella Liability         4/19/95-96  National Union Fire Insurance Co.    BE3097160    $5,000,000 Each          $10,000 SIR
                                       (AIG)                                             Occurrence            
------------------------------------------------------------------------------------------------------------------------------------
Commercial Property/       4/19/95-96  Hartford Lloyds Insurance Co.        61UECLC6597  $230,000 Off. Cont.      1,000 Cont.
Electronic Equipment                                                                     $290,000 Elec. Equip.  $250 Elec. Equip 
                                                                                                                Per Occurrence
------------------------------------------------------------------------------------------------------------------------------------
Contractors Equipment      4/19/95-96  Hartford Insurance Company           61MSLC5767   $ 13,533,648          $25,000 Theft
                                                                                                               $10,000 AOP
                                                                                                               Per Occurrence
------------------------------------------------------------------------------------------------------------------------------------
</TABLE> 
  
<PAGE>
 
<TABLE> 
<CAPTION> 

-----------------------------------------------------------------------------------------------------------------------------------
TYPE OF COVERAGE                   POLICY          INSURER                     POLICY NO.       LIMITS          DEDUCTIBLE
                                   DATES                                                                     
-----------------------------------------------------------------------------------------------------------------------------------
<S>                             <C>         <C>                               <C>          <C>                <C> 
Directors & Officers Liability  9/19/94-95  Aetna Casualty & Surety Company   095001738BCA $2,000,000 occ/agg Refer to Summary
-----------------------------------------------------------------------------------------------------------------------------------
Foreign Liability Package -     2/22/95-96  CIGNA Insurance Company           PFF047474    $1,000,000 occur.      None
General Liability/Auto Liab./                                                                                
Workers Comp. & Empl. Liab.                                                                                  
-----------------------------------------------------------------------------------------------------------------------------------
Marine Package - Australian      3/15/95     HIH Casualty & General Insurance  MOA9510340  Charterers - $ 5M  Charterers - $7,500
                                            Ltd.                                           Hull - $412,500        Hull - $5,000
                                to Job                                                     Cargo - As Sched.      Cargo - $5,000 
                                Completion                                                 P&I - $ 5M              Each Incident
-----------------------------------------------------------------------------------------------------------------------------------
</TABLE> 
<PAGE>
 
                                 SCHEDULE 7.02
                           To the Guaranty Agreement

                                Permitted Liens

Universal Seismic Associates, Inc.:

<TABLE> 
<CAPTION> 
     Secured Party                                State/Cty.     Filing No.
     -------------                                ----------     ----------
     <S>                                          <C>            <C> 
     *Sentry Financial Corporation                    MS           646988
     *Sentry Financial Corporation                    NM         920722029
     *Sentry Financial Corporation                    OK           037535
     *Sentry Financial Corporation                    TX         92-142154
     *Sentry Financial Corporation                    LA         09-911764
</TABLE> 

Universal Seismic Acquisition, Inc.:

<TABLE> 
<CAPTION> 
     Secured Party                                State/Cty.     Filing No.
     -------------                                ----------     ----------
     <S>                                          <C>            <C> 
     *Sentry Financial Corporation                    MS           599774
     *Sentry Financial Corporation                    NM         911223031
     *Sentry Financial Corporation                    OK           062451
     -Fidelity Funding, Inc.                          TX         95-172732
     *Sentry Financial Corporation                    LA         09-904369
</TABLE> 

Universal Seismic Technologies, Inc.:

<TABLE> 
<CAPTION> 
     Secured Party                                State/Cty.     Filing No.
     -------------                                ----------     ----------
     <S>                                          <C>            <C> 
     -Fidelity Funding, Inc.                          TX         95-197830
     -Fidelity Funding, Inc.                          TX         95-204420
</TABLE> 

Marine Automated Surveys, Inc.:

<TABLE> 
<CAPTION> 
     Secured Party                                State/Cty.     Filing No.
     -------------                                ----------     ----------
     <S>                                          <C>            <C> 
     Connecticut General Life Insurance Co.           TX         91-023503
</TABLE> 

*-    Such lien shall be a "Permitted Lien" only to the extent such lien covers 
      the equipment described on Annex I to this Schedule 7.02.

-.    Such lien shall be a "Permitted Lien" only to the extent such lien does 
      not cover the collateral that is subject to the Security Documents.

                                  Page 1 of 3
<PAGE>
 
                                 SCHEDULE 7.02
                           To the Guaranty Agreement

                                Permitted Liens

The following financing statements were filed for informational purposes and 
relate to operating leases with respect to certain equipment currently in the 
possession of, but not owned by or recorded as an asset of, Universal Seismic 
Associates, Inc. or its Subsidiaries:

Universal Seismic Associates, Inc.:

<TABLE> 
<CAPTION> 

        Secured Party                                State/Cty.        Filing No.
        -------------                                ----------        ----------
        <S>                                          <C>               <C> 
        Newcourt Credit Group, Inc.                     AL              B 95-22202
        Newcourt Credit Group, Inc.                     MS                895255
        Newcourt Credit Group, Inc.                     NM              950530096
        Newcourt Credit Group, Inc.                     OK                NO1752
        Glesby-Marks Corporation                        TX              94-026517
        Glesby-Marks Corporation                        TX              94-028683
        Glesby-Marks Corporation                        TX              94-053248
        Glesby-Marks Corporation                        TX              94-105220
        Glesby-Marks Corporation                        TX              94-172325
        Glesby-Marks Corporation                        TX              94-191289
        Glesby-Marks Corporation                        TX              94-219776
        LDI Corporation                                 TX              94-224526
        Glesby-Marks Corporation                        TX              94-224801
        Glesby-Marks Corporation                        TX              94-224802
        Glesby-Marks Corporation                        TX              94-232430
        Glesby-Marks Corporation                        TX              94-238037
        Glesby-Marks Corporation                        TX              94-238038
        Glesby-Marks Corporation                        TX              95-128331
        Glesby-Marks Corporation                        TX              95-204213
        Glesby-Marks Corporation                        TX              95-204214
        Glesby-Marks Corporation                        TX              95-204215
        Glesby-Marks Corporation                        TX              95-221807
        Glesby-Marks Corporation                        TX              95-221808
        Newcourt Credit Group, Inc.                     TX              94-105653
        NYNEX Credit Company                            TX              95-230465
        NYNEX Credit Company                        Harris (TX)           903208
        US Bankcorp                                     TX              95-126024
        Global Charter Corporation                      LA              36-110792
        Glesby-Marks Corporation                        TX              96-053243
</TABLE> 


                                  Page 2 of 3
<PAGE>
 

                                 SCHEDULE 7.02
                           To the Guaranty Agreement

                                Permitted Liens


        Secured Party                               State/Cty.     Filing No.
        -------------                               ----------     ----------

        Glesby-Marks Corporation                        TX         96-053244
        Glesby-Marks Corporation                        TX         96-074562
        Glesby-Marks Corporation                        TX         96-098976
        Glesby-Marks Corporation                        TX         96-098977
        Glesby-Marks Corporation                        TX         96-119416
        Glesby-Marks Corporation                        TX         96-119417
        Glesby-Marks Corporation                        TX         96-132529
        Glesby-Marks Corporation                        TX         96-141075
        Global Charter Corporation                      TX         96-184776


Universal Seismic Acquisition, Inc.:

        Secured Party                               State/Cty.     Filing No.
        -------------                               ----------     ----------

        NYNEX Credit Company                            TX         95-230466
        NYNEX Credit Company                        Harris (TX)      903207





                                  Page 3 of 3
<PAGE>
 
                            ANNEX I TO SCHEDULE 7.0

I.    Equipment:

<TABLE> 
<CAPTION> 
Qty             Vendor                  Description                                  Serial No.
---             ------                  -----------                                  ----------
<S>             <C>                     <C>                                           <C> 

32              Input/Output            RSX I/O System Two
2               Input/Output            Adv, Line-Tap, I/O System Two
50              Input/Output            Battery Pack, Single TC, Type 7
2               Input/Output            Battery Charger, I/O SO Port
2               Input/Output            PC Assy, Seismic Memory
3               Input/Output            PC Assy, Seismic Memory
11              Input/Output            Rack Assy., RSC
600             Mark Products           Geophone Strings w/12 L-200 Geophone and 2 MPS-4 Connectors
108             Mark Products           Variable Spacing 9 Takeout 1080 Ft. RSC to RSC Cables
54              Mark Products           RSC to RSC Back to Back Connectors
4               Mark Products           Long Distance LT to LT Cables 1500 Ft. Long
4               Mark Products           LT to Near RSC 7 Ft. Long
200             Mark Products           MJC w/d200, 10HZ, 380 OHM Geophones Installed 
                                        in Case with 3" Spike on 180 Foot Lead w/MPS-4's
25              Mark Products           RSC to RSC Cable 1050 Foot Long w/Amphip 20F-16S Connectors
8               Mark Products           1600 Foot LT to LT I/O Cables, Coil and Tape
5               Pelton Company          FGVCE-5 Advance II Vibrator Control Elect. Unit Ver. 5
40              Pelton Company          WGEXTC External Control Cables
5               Pelton Company          WGRD Remote Down Cable
5               Pelton Company          FGV18CPA-4 Connector Panel Cable
5               Pelton Company          FGLIFT Lift Cable Assembly with Actuators
5               Pelton Company          WRIBC Radio Interconnect Box
5               Pelton Company          W2RC Radio Cable
10              Pelton Company          FGDACCA-5 Dual MS Accelerometer
5               Pelton Company          AM2MAN ESG/VIB Manual Ver. 5
5               Pelton Company          YR3rd Party/Third Party Royalty Fee
1               Pelton Company          FGESG-5 Advance II Endcode Sweep Generator System Ver. 5
1               Pelton Company          WESGRSC-5 ESG Recording System Cable
1               Pelton Company          WRIBC Radio Interconnect Box
2               Pelton Company          AM2MAN-5 ESG/VIB Manuals Ver. 5
</TABLE> 
II.   Security Deposits - all security deposits (and the proceeds and products 
    thereof) held by Sentry