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                                PROMISSORY NOTE

U.S.$550,000                                            Dated: October 31, 1996

        FOR VALUE RECEIVED, the undersigned GRANT GEOPHYSICAL, INC., a Delaware
corporation with offices at 16850 Park Row, Houston, Texas 77084 ("Borrower"),
promises to pay to the order of WESTGATE INTERNATIONAL, L.P., a Cayman Islands
exempted limited partnership ("Lender"), at c/o Midland Bank Trust Corporation
(Cayman) Limited, P.O. Box 1109, Mary Street, Grand Cayman, Cayman Islands,
BWI, in lawful money of the United States, the principal sum of Five Hundred
Fifty Thousand United States Dollars (U.S.$550,000) on demand, but in no event
later than the date which is sixty (60) days from the date of this promissory
note (the "Note") indicated above and to pay interest on the principal sum
outstanding under this Note at the rate of 15% per annum, also due and payable
on the date upon which the outstanding principal balance hereunder is required
to be paid (the "Maturity Date"). Accrual of interest shall commence on the
first day to occur after the date hereof and shall continue until payment in
full of the principal sum and all other amounts due hereunder have been made.
The principal of, and interest on, this Note are payable in such currency of
the United States of America as of the time of payment is legal tender for
payment of public and private debts.

        This Note is subject to the following additional provisions:

        1.  INTEREST AND PAYMENT APPLICATION.  Interest shall be calculated on 
a 360 day year simple interest basis and paid for the actual number of days
elapsed. All interest due hereunder shall be payable at the Maturity Date.
Notwithstanding anything contained herein, the outstanding principal balance and
interest due hereunder shall bear interest, from and after the occurrence and
during the continuance of a default hereunder, at the rate equal to the lower
of twenty-five percent (25%) per annum or the highest rate permitted by law.
Unless otherwise agreed or required by applicable law, payments will be applied
first to any unpaid collection costs, then to unpaid interest and fees and any
remaining amount to principal.

        2.  PREPAYMENT.  Borrower may pre-pay all or any part of this Note
at any time, without penalty, provided that no pre-payment shall be less than
$100,000.

        3.  TAXES.  All payments on account of the principal of and interest
on this Note and all other amounts payable under this Note (whether made by
Borrower or any other person) to or for the account of Lender hereunder shall
be made free and clear of and without reduction by reason of any and all
present and future income, stamp, registration and other taxes, levies, duties,
costs and charges whatsoever imposed, assessed, levied or collected by the
United States or any political subdivision or taxing authority thereof or
therein, on or in respect of this Note (all such taxes, levies, duties, costs
and charges, together with interest thereon and penalties with respect thereto,
if any, being herein collectively called "United States Taxes"), all of which
will be for the account of and paid by Borrower. Should any such payment be
subject to any United States Taxes and the provisions of the preceding sentence
of this Section 3 either cannot be effected or do not result in the Lender
actually receiving free and clear of all United States Taxes an amount equal to
the full amount provided for under this Note, Borrower shall pay to Lender such
additional amounts as may be necessary to ensure that Lender receives a net
amount equal to the full amount which it would have received had such payment
not been made subject to United States Taxes. In addition to the United States
Taxes paid by Borrower  
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or additional amounts paid to Lender, in each case pursuant to the preceding
provisions of this Section 3 ("Additional Payments"), Borrower shall also pay
to Lender upon demand such additional amounts as may be necessary to compensate
Lender, on an after-tax basis, for any tax or levy imposed or assessed by any
jurisdiction on or with respect to any such Additional Payments (including any
income taxes payable by Lender with respect to Additional Payments pursuant to
the income tax laws of the jurisdiction of its principal office or lending or
of any political subdivision or taxing authority thereof).

        4.  NO IMPAIRMENT.  Borrower shall not intentionally take any action
which would impair the rights of Lender hereunder.

        5.  OBLIGATIONS ABSOLUTE.  No provision of this Note shall alter or
impair the obligation of Borrower, which is absolute and unconditional, to pay
the principal of, and interest on, this Note at the time, place and rate, and
in the manner, herein prescribed.

        6.  WAIVERS OF DEMAND, ETC.  Borrower and any other person who signs,
guarantees or endorses this Note, to the extent allowed by law, hereby
expressly waives demand and presentment for payment, notice of nonpayment,
protest, notice of protest, notice of dishonor, notice of acceleration or
intent to accelerate, all other notices whatsoever and bringing of suit and
diligence in taking any action to collect amounts called for hereunder, and
will be directly and primarily liable for the payment of all sums owing and to
be owing hereon, regardless of and without any notice, diligence, act or
omission as or with respect to the collection of any amount called for
hereunder.

        7.  REPLACEMENT NOTE.  In the event that Lender notifies Borrower
that this Note has been lost, stolen, or destroyed, a replacement Note
identical in all respects to the original Note (except for the outstanding
principal amount, if different than that shown on the original Note), shall be
delivered to Lender, provided that the Lender executes and delivers to Borrower
an agreement reasonably satisfactory to Borrower to indemnify Borrower from any
loss incurred by it in connection with this Note.

        8.  PAYMENT OF EXPENSES.  Borrower agrees to pay all debts and expenses,
including reasonable attorneys' fees and expenses, which may be incurred by the
Lender in preparing, administering or enforcing this Note and/or collecting any
amount due under this Note or the Loan Agreement.

        9.  REPRESENTATIONS AND WARRANTIES.  Borrower hereby represents and
warrants that (i) Borrower is a corporation duly incorporated and existing in
good standing under the laws of the State of Delaware and has the requisite
corporate power to own its properties and to carry on its business as now being
conducted; (ii) Borrower has the requisite corporate power and authority to
enter into and perform this Note in accordance with the terms hereof; (iii) the
execution and delivery of this Note has been duly authorized by the Borrower's
Board of Directors and any other necessary corporate action, and no further
consent or authorization of Borrower or its stockholders is required; (iv) this
Note has been duly executed and delivered by Borrower, (v) this Note
constitutes the valid and binding obligation of Borrower enforceable against
Borrower in accordance with its terms, subject to applicable bankruptcy,
insolvency and similar laws affecting creditors' rights generally and to
general principles of equity; and (vi) the execution, delivery and performance
of this Note by Borrower will not result in a violation of the charter or the
by-laws of Borrower, or result in a violation of any applicable law, 





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rule, regulation, order, judgment or decree applicable to Borrower or by which
its assets may be bound or affected.

        10.  SAVINGS CLAUSE.  In Case any provision of this Note is held by a
court of competent jurisdiction to be excessive in scope or otherwise invalid
or unenforceable, such provision shall be adjusted rather than voided, if
possible, so that it is enforceable to the maximum extent possible, and the
validity and enforceability of the remaining provisions of this Note will not
in any way be affected or impaired thereby. In no event shall the amount of
interest paid hereunder exceed the maximum rate of interest on the unpaid
principal balance hereof allowable by applicable law. If any sum is collected
in excess of the applicable maximum rate, the excess collected shall be applied
to reduce the principal debt. If the interest actually collected hereunder is
still in excess of the applicable maximum rate, the interest rate shall be
reduced so as not to exceed the maximum amount allowable under law.

        11.  AMENDMENT.  Neither this Note nor any term hereof may be amended,
waived, discharged or terminated other than by a written instrument signed by
Borrower and Lender.

        12.  ASSIGNMENT, ETC.  Lender may without notice transfer or assign
this Note or any interest herein and may mortgage, encumber or transfer any of
its rights or interest in and to this Note or any part hereof and, without
limitation, each assignee, transferee and mortgagee (which may include any
affiliate of the Lender) shall have the right to transfer or assign its
interest. Each such assignee, transferee and mortgagee shall have all of the
rights of Lender under this Note. This Note shall be binding upon Borrower and
its successors and shall inure to the benefit of the Lender and its successors
and assigns.

        13.  NO WAIVER.  No failure on the part of Lender to exercise, and no
delay in exercising any right, remedy or power hereunder shall operate as a
waiver thereof, nor shall any single or partial exercise by Lender of any
right, remedy or power hereunder preclude any other or future exercise of any
other right, remedy or power. Each and every right, remedy or power hereby
granted to Lender or allowed it by law or other agreement shall be cumulative
and not exclusive of any other, and may be exercised by Lender from time to 
time.

        14.  MISCELLANEOUS.  Unless otherwise provided herein, any notice or
other communication to Borrower hereunder shall be sufficiently given if in
writing and personally delivered or mailed to Borrower by certified mail,
return receipt requested, at its address set forth above or such other address
as it may designate for itself in such notice to Lender, and communications
shall be deemed to have been received when delivered personally or, if sent by
mail or facsimile, then when actually received by the party to whom it is
addressed. Whenever the sense of this Note requires, words in the singular
shall be deemed to include the plural and words in the plural shall be deemed
to include the singular. Upon any change in the terms of this Note, and unless
otherwise expressly stated in writing, no party who signs this Note, whether as
maker, guarantor, accommodation maker or endorser, shall be released from
liability. All such parties agree that Lender may (1) renew, extend (repeatedly
and for any length of time) or modify this Note, or release any party or any
guarantor or collateral, (2) impair, fail to realize upon or perfect any
security interest lender may have from time to time in collateral, or modify
this Note, or release any party or any guarantor or collateral, or (3) take
any other action deemed necessary by Lender, in each case without the consent
of or notice to anyone and without releasing Borrower or any guarantor from
any liability.

        15.  CHOICE OF LAW AND VENUE; WAIVER OF JURY TRIAL.  THIS NOTE SHALL BE
CONSTRUED UNDER THE LAWS OF THE STATE OF NEW YORK, WITHOUT REGARD



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TO PRINCIPLES OF CONFLICTS OF LAW OR CHOICE OF LAW. Borrower hereby agrees that
all actions or proceedings arising directly or indirectly from or in
connection with this Note shall, at Lender's sole option, be litigated only in
the Supreme Court of the State of New York or the United States District Court
for the Southern District of New York located in New York County, New York.
Borrower consents to the exclusive jurisdiction and venue of the foregoing
courts and consents that any process or notice of motion or other application
to either of said courts or a judge thereof may be served inside or outside the
State of New York or the Southern District of New York by certified or
registered mail, return receipt requested, directed to Borrower at its address
set forth in this Note (and service so made shall be deemed "personal service"
and be deemed complete five (5) days after the same has been posted as
aforesaid) or by personal service or in such other manner as may be permissible
under the rules of said courts. Borrower hereby waives any right to a jury
trial in connection with any litigation pursuant to this Note.

        IN WITNESS WHEREOF, Borrower has caused this instrument to be duly
executed by an officer thereunto duly authorized.



                                        GRANT GEOPHYSICAL, INC.



                                        By:  /s/ WILLIAM B. CLEVELAND
                                           ----------------------------
                                        Print Name:    William B. Cleveland
                                                       -----------------------
                                        Print Title:   Vice Pres. Finance
                                                       Secretary and Treasurer
                                                       -----------------------


ATTEST

/s/ D. HUGH FRASER, JR.
-----------------------
    D. HUGH FRASER, JR. 
    VICE PRESIDENT
    NORTH AMERICA





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