<PAGE>


                        TUBOSCOPE STOCK OPTION AGREEMENT
                        --------------------------------

     STOCK OPTION AGREEMENT, dated as of March 22, 2000 (this "Agreement"), by
                                                               ---------
and between Varco, a California corporation (the "Grantee"), and Tuboscope, a
                                                  -------
Delaware corporation (the "Grantor").
                           -------

     WHEREAS, the Grantee and the Grantor are entering into an Agreement and
Plan of Merger, dated as of the date hereof (the "Merger Agreement"), which
                                                  ----------------
provides, among other things, for the merger (the "Merger") of the Grantee with
                                                   ------
and into the Grantor;

     WHEREAS, as a condition to its willingness to enter into the Merger
Agreement, the Grantee has requested that the Grantor grant to the Grantee an
option to purchase certain shares of the authorized and unissued Common Stock of
the Grantor (the "Common Stock") upon the terms and subject to the conditions
                  ------------
hereof; and

     WHEREAS, in order to induce the Grantee to enter into the Merger Agreement,
the Grantor is willing to grant the Grantee the requested option.

     NOW, THEREFORE, in consideration of the representations, warranties and
covenants contained herein and in the Merger Agreement, the parties hereto agree
as follows:

     1.  The Option; Exercise; Adjustments; Payment of Spread; Termination.
         -----------------------------------------------------------------

         (a)     Contemporaneously herewith the Grantee and the Grantor are
entering into the Merger Agreement. Subject to the other terms and conditions
set forth herein, the Grantor hereby grants to the Grantee an irrevocable option
(the "Option") to purchase up to 8,908,653 shares (representing approximately
      ------
19.9% of the outstanding shares of Common Stock as of the date hereof) of Common
Stock (the "Option Shares") at a cash purchase price equal to $17.00 per Option
            -------------
Share (the "Purchase Price"). Subject to the conditions set forth in Section 2,
            --------------
the Option may be exercised by the Grantee, in whole or in part, at any time, or
from time to time, following the occurrence of any event as a result of which
the Grantee is unconditionally entitled to receive the Tuboscope Termination Fee
(as defined in the Merger Agreement) pursuant to Section 8.03(c) of the Merger
Agreement and prior to the termination of the Option in accordance with the
terms of this Agreement.

         (b)     Without limiting any restriction on the Grantor contained in
this Agreement or the Merger Agreement, in the event of any change in the number
of issued and outstanding shares of Common Stock by reason of any stock
dividend, stock split, split-up, recapitalization, merger or other change in the
corporate or capital structure of the Grantor, the number and type of Option
Shares subject to the Option and the purchase price per Option Share shall be
appropriately adjusted to restore the Grantee to its rights hereunder, including
its right to purchase Option Shares representing 19.9% of the capital stock of
the Grantor entitled to vote generally for the election of the directors of the
Grantor which is issued and outstanding immediately prior to the exercise of the
Option at an aggregate purchase price equal to the Purchase Price multiplied by
8,908,653.

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         (c)     In the event the Grantee wishes to exercise the Option, the
Grantee shall send a written notice to the Grantor (the "Exercise Notice")
                                                         ---------------
specifying the total number of Option Shares that the Grantee wishes to purchase
and a date (subject to the requirements of the Hart-Scott-Rodino Antitrust
Improvements Act of 1976, as amended (the "HSR Act")) not later than 10 business
                                           -------
days and not earlier than the next business day following the date such notice
is given for the closing of such purchase.

         (d)     After the occurrence of any event as a result of which the
Grantee is unconditionally entitled to receive the Tuboscope Termination Fee
pursuant to Section 8.03(c) of the Merger Agreement, the Grantee may (i) at any
time the Option is then exercisable pursuant to the terms of Section 1(a) hereof
elect, in lieu of exercising the Option to purchase Option Shares provided in
Section 1(a) hereof, to send a written notice to the Grantor (the "Cash
                                                                   ----
Exercise Notice") specifying a date not later than 20 business days and not
---------------
earlier than 10 business days following the date such notice is given on which
date the Grantor shall pay to the Grantee an amount in cash equal to the Spread
(as hereinafter defined) multiplied by all or such portion of the Option Shares
subject to the Option as Grantee shall specify, or (ii) at any time prior to 30
days after the first anniversary of the Merger Termination Date (as defined in
Section 1(e)), if the Grantee has exercised the Option and purchased the Option
Shares hereunder, Grantee may send a written notice to the Grantor (the "Put
                                                                         ---
Notice") specifying a date not later than 20 business days and not earlier than
------
10 business days following the date such notice is given on which date the
Grantee may sell to the Grantor Option Shares purchased hereunder and the
Grantor shall pay to the Grantee an amount in cash equal to the higher of (m)
the Alternative Purchase Price (as hereinafter defined) or (n) the average of
the closing sales prices of the shares of Common Stock on the New York Stock
Exchange (the "NYSE") for the five trading days ending five days prior to the
               ----
date the Put Notice is given, multiplied by the number of such Option Shares to
be sold by the Grantee to the Grantor on such date (such purchase and sale to be
closed in a manner substantially consistent with the procedures outlined in
Section 3 hereof). As used herein "Spread" shall mean the the highest price per
                                   ------
share of Common Stock (including any brokerage commissions, transfer taxes and
soliciting dealers' fees) paid by any person in an Alternative Transaction (as
defined in Section 8.03(g) of the Merger Agreement) (the "Alternative Purchase
                                                          --------------------
Price") or (y) the average of the closing sales prices of the shares of Common
-----
Stock on the NYSE for the five trading days ending five days prior to the date
of the Cash Exercise Notice is given. If the Alternative Purchase Price includes
any property other than cash, the Alternative Purchase Price shall be the sum of
(A) the fixed cash amount, if any, included in the Alternative Purchase Price
plus (B) the fair market value of such other property determined in accordance
with the procedures set forth in Section 7(b) (but using the date of the Cash
Exercise Notice or the Put Notice, as the case may be, is given). Upon exercise
of the Grantee's right to receive cash pursuant to Section 1(d)(i) and the
payment of such cash to the Grantee, the obligations of the Grantor to deliver
Option Shares pursuant to Section 3 shall be terminated with respect to such
number of Option Shares for which the Grantee shall have elected to be paid the
Spread.

         (e)     The right to exercise the Option shall terminate at the
earliest of (i) the Effective Time (as defined in the Merger Agreement), (ii)
the termination of the Merger

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Agreement pursuant to circumstances under which the Grantee is not entitled to
receive the Tuboscope Termination Fee pursuant to Section 8.03(c) of the Merger
Agreement, (iii) the date on which the Grantee realizes a Total Profit equal to
the Profit Limit (as such terms are defined in Section 10) and (iv) 180 days
after the date (the "Merger Termination Date") on which the Merger Agreement is
                     -----------------------
terminated pursuant to circumstances under which the Grantee is entitled to
receive the Varco Termination Fee pursuant to Section 8.03(c) of the Merger
Agreement (the date referred to in clause (iv) being hereinafter referred to as
the "Option Expiration Date"); provided that if the Option cannot be exercised
     ----------------------
or the Option Shares cannot be delivered to Grantee upon such exercise because
the conditions set forth in Section 2(a) or Section 2(b) hereof have not yet
been satisfied, the Option Expiration Date shall be extended until 30 days after
such impediment to exercise has been removed.

    2.   Conditions to Delivery of Option Shares.  The Grantor's obligation to
         ---------------------------------------
deliver Option Shares upon exercise of the Option is subject to the following
conditions:

         (a)     No preliminary or permanent injunction or other order issued by
any federal or state court of competent jurisdiction in the United States
prohibiting the delivery of the Option Shares shall be in effect;

         (b)     Any applicable waiting periods under the HSR Act shall have
expired or been terminated; and

         (c)     The Grantee shall have become entitled to terminate the Merger
Agreement under circumstances that would entitle the Grantee to receive the
Tuboscope Termination Fee pursuant to Section 8.03(c) of the Merger Agreement.

    3.   The Closing.
         -----------

         (a)     Any closing hereunder shall take place on the date specified by
the Grantee in its Exercise Notice at 9:00 A.M., local time, at the offices of
Latham & Watkins, 650 Town Center Drive, Costa Mesa, California, or, if the
conditions set forth in Section 2(a) or 2(b) have not then been satisfied, on
the second business day following the satisfaction of such conditions, or at
such other time and place as the parties hereto may agree (the "Closing Date").
                                                                -------------
On the Closing Date, the Grantor will deliver to the Grantee a certificate or
certificates representing the Option Shares in the denominations designated by
the Grantee in its Exercise Notice and the Grantee will purchase such Option
Shares from the Grantor at the price per Option Share equal to the Purchase
Price. Unless otherwise specified in this Agreement, any payment made by the
Grantee to the Grantor, or by the Grantor to the Grantee, pursuant to this
Agreement shall be made by certified or official bank check or by wire transfer
of immediately available funds to a bank designated by the party receiving such
funds.

         (b)     Certificates for the Option Shares delivered on the Closing
Date will have typed or printed thereon a restrictive legend which will read
substantially as follows:

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          "THE SECURITIES REPRESENTED BY THIS CERTIFICATE HAVE NOT BEEN
          REGISTERED UNDER THE SECURITIES ACT OF 1933 AND MAY BE REOFFERED OR
          SOLD ONLY IF SO REGISTERED OR IF AN EXEMPTION FROM SUCH REGISTRATION
          IS AVAILABLE.  SUCH SECURITIES ARE ALSO SUBJECT TO ADDITIONAL
          RESTRICTIONS ON TRANSFER AS SET FORTH IN THE TUBOSCOPE STOCK OPTION
          AGREEMENT DATED AS OF MARCH 22, 2000, A COPY OF WHICH MAY BE OBTAINED
          FROM THE SECRETARY OF TUBOSCOPE AT ITS PRINCIPAL EXECUTIVE OFFICES."

It is understood and agreed that (i) the reference to restrictions arising under
the Securities Act of 1933, as amended (the "Securities Act"), in the above
                                             --------------
legend will be removed by delivery of substitute certificate(s) without such
reference if such Option Shares have been registered pursuant to the Securities
Act, such Option Shares have been sold in reliance on and in accordance with
Rule 144 under the Securities Act or Grantee has delivered to Grantor a copy of
a letter from the staff of the Securities and Exchange Commission, or an opinion
of counsel in form and substance reasonably satisfactory to Grantor and its
counsel, to the effect that such legend is not required for purposes of the
Securities Act and (ii) the reference to restrictions pursuant to this Agreement
in the above legend will be removed by delivery of substitute certificate(s)
without such reference if the Option Shares evidenced by certificate(s)
containing such reference have been sold or transferred in compliance with the
provisions of this Agreement under circumstances that do not require the
retention of such reference.

    4.   Representations and Warranties of the Grantor.  The Grantor represents
         ---------------------------------------------
and warrants to the Grantee that:  (a) the Grantor is a corporation duly
organized, validly existing and in good standing under the laws of the State of
California and has the requisite corporate power and authority to enter into and
perform this Agreement; (b) the execution and delivery of this Agreement by the
Grantor and the consummation by it of the transactions contemplated hereby have
been duly authorized by the Board of Directors of the Grantor and this Agreement
has been duly executed and delivered by a duly authorized officer of the Grantor
and constitutes a valid and binding obligation of the Grantor, enforceable in
accordance with its terms, subject to bankruptcy, insolvency, fraudulent
transfer, reorganization, moratorium and similar laws of general applicability
relating to or affecting creditors' rights, to general equity principles and to
the California General Corporation Law; (c) the Grantor has taken all necessary
corporate action to authorize and reserve the Option Shares issuable upon
exercise of the Option and the Option Shares, when issued and delivered by the
Grantor upon the exercise of the Option in accordance with the terms of this
Agreement, will be duly authorized, validly issued, fully paid and non-
assessable and free of any lien, security interest or other adverse claim and
free of any preemptive rights; (d) except as otherwise required by the HSR Act
and, except for routine filings under the Securities Exchange Act of 1934, as
amended, and the listing of the Option Shares in accordance with Section 6, the
execution and delivery of this Agreement by the Grantor and the consummation by
it of the transactions contemplated hereby do not require the consent, waiver,

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approval or authorization of or any filing with any person or public authority
and will not violate, require a consent or waiver under, result in a breach of
or the acceleration of any obligation under, or constitute a default under, any
provision of any charter or by-law, indenture, mortgage, lien, lease, agreement,
contract, instrument, order, law, rule, regulation, stock market rule, judgment,
ordinance, decree or restriction by which the Grantor or any of its subsidiaries
or any of their respective properties or assets is bound; and (e) no "fair
price," "moratorium," "control share acquisition" or other form of antitakeover
statute or regulation is or shall be applicable to the acquisition of Option
Shares pursuant to this Agreement.

    5.   Representations and Warranties of the Grantee.  The Grantee represents
         ---------------------------------------------
and warrants to the Grantor that:  (a) the execution and delivery of this
Agreement by the Grantee and the consummation by it of the transactions
contemplated hereby have been duly authorized by all necessary corporate action
on the part of the Grantee and this Agreement has been duly executed and
delivered by a duly authorized officer of the Grantee and constitutes a valid
and binding obligation of the Grantee; and (b) the Grantee is acquiring the
Option and, if and when it exercises the Option, will be acquiring the Option
Shares issuable upon the exercise thereof for its own account and not with a
view to distribution or resale in any manner which would be in violation of the
Securities Act.

    6.   Listing of Option Shares; HSR Act Filings; Governmental Consents.  The
         ----------------------------------------------------------------
Grantor shall use its best efforts to cause the Option Shares to be approved for
listing on the NYSE, subject to official notice of issuance, prior to the
Closing Date; provided, however, that if the Grantor is unable to effect such
              --------  -------
listing on the NYSE by the Closing Date, the Grantor will nevertheless be
obligated to deliver the Option Shares upon the Closing Date.  The Grantor shall
as promptly as practicable make all necessary filings with respect to this
Agreement and the Option required under the HSR Act and use its best efforts to
obtain all necessary approvals thereunder as promptly as practicable.  Each of
the parties hereto will use its best efforts to obtain consents of all third
parties and governmental authorities, if any, necessary to the consummation of
the transactions contemplated herein.

    7.   Right of First Refusal.  If the Grantee exercises the Option in whole
         ----------------------
or in part and at any time thereafter and prior to the earlier of (a) the
occurrence of a Change in Control Event (as defined herein) or (b) 30 days after
the first anniversary of the Merger Termination Date, seeks to sell all or any
part of the Option Shares purchased (i) in a transaction registered under the
Securities Act (other than in a registered public offering in which the
underwriters are instructed to achieve a broad public distribution) or (ii) in a
transaction not required to be registered under the Securities Act (other than
in a transfer by operation of law upon consummation of a merger), it shall give
the Grantor (or a designee of the Grantor) the opportunity, in the following
manner, to purchase such Option Shares:

         (a)     The Grantee shall give notice to the Grantor in writing of its
intent to sell Option Shares (a "Disposition Notice"), specifying the number of
                                 ------------------
Option Shares to be sold, the price and, if applicable, the identity of the
proposed transferee and the material terms of any agreement relating thereto.
For purposes of this Section 7, if the Disposition Notice is given with respect
to the sale of the Option Shares pursuant to a tender or exchange officer, it
shall be

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assumed that all Option Shares tendered will be accepted for payment. The
Disposition Notice may be given at any time, including prior to the giving of
any Exercise Notice.

         (b)     The Grantor or its designee shall have the right, exercisable
by written notice given to the Grantee within five business days after receipt
of a Disposition Notice (or, if applicable, in the case of a proposed sale
pursuant to a tender or exchange offer for shares of Common Stock, by written
notice given to the Grantee at least two business days prior to the then
announced expiration date of such tender or exchange offer (the "Expiration
                                                                 ----------
Date") if such Disposition Notice was given at least four business days prior to
-----
such Expiration Date), to purchase all, but not less than all, of the Option
Shares specified in the Disposition Notice at the price set forth in the
Disposition Notice. If the purchase price specified in the Disposition Notice
includes any property other than cash, the purchase price to be paid by the
Grantor shall be an amount of cash equal to the sum of (i) the cash included in
the purchase price plus (ii) the fair market value of such other property at the
date of the Disposition Notice. If such other property consists of securities
with an existing public trading market, the average closing price (or the
average closing bid and asked price if closing prices are unavailable) for such
securities on their principal public trading market for the five trading days
ending five days prior to the date of the Disposition Notice shall be deemed to
equal the fair market value of such property. If such other property consists of
something other than cash or securities with an existing public trading market
and, at the time of the closing referred to in paragraph (c) below, agreement on
the value of such other property has not been reached, the higher of (i) the
cash included in the purchase price and (ii) the average closing price of the
Common Stock on the NYSE for the five trading days ending five days prior to the
date of the Disposition Notice shall be used as the per share purchase price;
provided, however, that promptly after the closing, the Grantee and the Grantor
--------  -------
or its designee, as the case may be, shall settle any additional amounts to be
paid or returned as a result of the determination of fair market value of such
other property made by a nationally recognized investment banking firm selected
by the Grantor and approved by the Grantee within 30 days of the closing. Such
determination shall be final and binding on all parties hereto. If, at the time
of the purchase of any Option Shares by the Grantor (or its designee) pursuant
to this Section 7, a tender or exchange offer is outstanding, then the Grantor
(or its designee) shall agree at the time of such purchase to promptly pay to
Grantee from time to time such additional amounts, if any, so that the
consideration received by Grantee with respect to each Option Share shall be
equal to the highest price paid for a share of Common Stock pursuant to such
tender or exchange, or pursuant to any other tender or exchange offer
outstanding at any time such tender or exchange offer is outstanding.

         (c)     If the Grantor exercises its right of first refusal hereunder,
the closing of the purchase of the Option Shares with respect to which such
right has been exercised shall take place within five business days after the
notice of such exercise (or, if applicable, in the case of a tender or exchange
offer, no later than one business day prior to the expiration date of the offer
if written notice was given within the time set forth in the parenthetical in
the first sentence of paragraph (b) above); provided, however, that at any time
                                            --------  -------
prior to the closing of the purchase of Option Shares hereunder, the Grantee may
determine not to sell the Option Shares and revoke the Disposition Notice and,
by so doing, cancel the Grantor's right of first refusal with respect to the

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disposition in question. The Grantor (or its designee) shall pay for the Option
Shares by wire transfer of immediately available funds to a bank designated by
the Grantee.

         (d)     If the Grantor does not exercise its right of first refusal
hereunder within the time specified for such exercise, the Grantee shall be free
for 90 days following the expiration of such time for exercise to sell the
Option Shares (or enter into an agreement to sell the Option Shares) specified
in the Disposition Notice, at the price specified in the Disposition Notice or
any price in excess thereof and otherwise on substantially the same terms set
forth in the Disposition Notice; provided that if such sale is not consummated
within such 90-day period (or the agreement to sell entered into in such 90-day
period is not thereafter performed in accordance with its terms), then the
provisions of this Section 7 will again apply to the sale of such Option Shares.

         (e)     For purposes of the Agreement, a "Change in Control Event"
                                                   -----------------------
shall be deemed to have occurred if (i) any person has acquired beneficial
ownership of more than 50% (excluding the Option Shares) of the outstanding
shares of Common Stock or (ii) the Grantor shall have entered into an agreement,
including without limitation an agreement in principle, providing for a merger
or other business combination involving the Grantor or the acquisition of 30% or
more of the assets of the Grantor and its subsidiaries, taken as a whole.

   8.    Repurchase of Option Shares.  If a Change in Control Event has not
         ---------------------------
occurred prior to the first anniversary date of the Merger Termination Date,
then beginning on such anniversary date, the Grantor shall have the right to
purchase (the "Repurchase Right") all, but not less than all, of the Option
               ----------------
Shares at the greater of (i) the Purchase Price, or (ii) the average closing
price of the Common Stock on the NYSE for the five trading days ending five days
prior to the date the Grantor gives written notice of its intention to exercise
the Repurchase Right.  If the Grantor does not exercise the Repurchase Right
within 30 days following the first anniversary of the Merger Termination Date,
the Repurchase Right shall terminate.  In the event the Grantor wishes to
exercise the Repurchase Right, the Grantor shall send a written notice to the
Grantee specifying a date (not later than 10 business days and not earlier than
two business days following the date such notice is given) for the closing of
such purchase.

    9.   Registration Rights.
         -------------------

         (a)     In the event that the Grantee shall desire to sell any of the
Option Shares within two years after the purchase of such Option Shares pursuant
to the exercise of the Option, and such sale requires, in the opinion of counsel
to the Grantee, which opinion shall be reasonably satisfactory to the Grantor
and its counsel, registration of such Option Shares under the Securities Act,
the Grantor will cooperate with the Grantee and any underwriters registering
such Option Shares for resale, including, without limitation, promptly filing
and using its best efforts to cause to be declared effective a registration
statement which complies with the requirements of applicable federal and state
securities laws and entering into an underwriting agreement with such
underwriters upon such terms and conditions as are customarily contained in
underwriting agreements with respect to secondary distributions; provided that
the Grantor shall not be required to have declared effective more than two
registration statements hereunder

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and shall be entitled to delay the filing or effectiveness of any registration
statement for up to 120 days in the aggregate if the offering would, in the
judgment of the Board of Directors of the Grantor, require premature disclosure
of any material corporate development or otherwise interfere with or adversely
affect any pending or proposed offering of securities of the Grantor or any
other material transaction involving the Grantor.

         (b)     If the Common Stock is registered pursuant to the provisions of
this Section 9, the Grantor agrees (i) to furnish copies of the registration
statement and the prospectus relating to the Option Shares covered thereby in
such numbers as the Grantee may from time to time reasonably request and (ii) if
any event shall occur as a result of which it becomes necessary to amend or
supplement any registration statement or prospectus, to prepare and file under
the applicable securities laws such amendments and supplements as may be
necessary to keep available for at least 90 days a prospectus covering the
Common Stock meeting the requirements of such securities laws, and to furnish to
the Grantee such numbers of copies of the registration statement and prospectus
as amended or supplemented as may reasonably be requested. The Grantor shall
bear the cost of the registration, including, but not limited to, all
registration and filing fees, printing expenses, and fees and disbursements of
counsel and accountants for the Grantor, except that the Grantee shall pay the
fees and disbursements of its counsel and the underwriting fees and selling
commissions applicable to the Option Shares sold by the Grantee. The Grantor
shall indemnify and hold harmless Grantee, its affiliates and its officers and
directors from and against any and all losses, claims, damages, liabilities and
expenses arising out of or based upon any statements contained in, omissions or
alleged omissions from, each registration statement filed pursuant to this
paragraph; provided, however, that this provision does not apply to any loss,
           --------  -------
liability, claim, damage or expense to the extent it arises out of any statement
or omission made in reliance upon and in conformity with written information
furnished to the Grantor by the Grantee, its affiliates or its officers
expressly for use in any registration statement (or any amendment thereto) or
any preliminary prospectus filed pursuant to this paragraph. The Grantor shall
also indemnify and hold harmless each underwriter and each person who controls
any underwriter within the meaning of either the Securities Act or the
Securities Exchange Act of 1934, as amended, against any and all losses, claims,
damages, liabilities and expenses arising out of or based upon any statements
contained in, omissions or alleged omissions from, each registration statement
filed pursuant to this paragraph; provided, however, that this provision does
                                  --------  -------
not apply to any loss, liability, claim, damage or expense to the extent it
arises out of any statement or omission made in reliance upon and in conformity
with written information furnished to the Grantor by the underwriters expressly
for use in any registration statement (or any amendment thereto) or any
preliminary prospectus filed pursuant to this paragraph.

    10.  Profit Limitation.
         -----------------

         (a)     Notwithstanding any other provision of this Agreement, in no
event shall the Grantee's Total Profit (as hereinafter defined) exceed
$35,000,000 (the "Profit Limit") and, if it otherwise would exceed such amount,
                  ------------
the Grantee, at its sole election, shall either (i) deliver to the Grantor for
cancellation Option Shares previously purchased by Grantee (valued at the

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average closing price of the Common Stock on the NYSE for the five trading days
ending on the trading date immediately preceding the date of delivery, (ii) pay
cash or deliver other consideration to the Grantor, or (iii) undertake any
combination thereof, so that Grantee's Total Profit shall not exceed the Profit
Limit after taking into account the foregoing actions.

         (b)     Notwithstanding any other provision of this Agreement, the
Option may not be exercised for a number of Option Shares as would, as of the
date of the Exercise Notice, result in a Notional Total Profit (as defined
below) of more than the Profit Limit and, if exercise of the Option otherwise
would exceed the Profit Limit, the Grantee, at its discretion, may increase the
Purchase Price for that number of Option Shares set forth in the Exercise Notice
so that the Notional Total Profit shall not exceed the Profit Limit; provided
that nothing in this sentence shall restrict any exercise of the Option
permitted hereby on any subsequent date at the Purchase Price set forth in
Section 1(a) hereof.

         (c)     As used herein, the term "Total Profit" shall mean the
                                           ------------
aggregate amount (before taxes) of the following: (i) the amount of cash
received by Grantee pursuant to Section 8.03(c) of the Merger Agreement, (ii)
(x) the amount received by Grantee pursuant to the Grantor's repurchase of
Option Shares pursuant to Sections 1(d), 7 or 8 hereof, less (y) the Grantee's
aggregate purchase price for such Option Shares, (iii) the amount received by
Grantee in respect of a Cash Exercise Notice pursuant to Section 1(d) hereof,
and (iv) (x) the net cash amounts received by Grantee pursuant to the sale of
Option Shares (or any other securities into which such Option Shares are
converted or exchanged) to any unaffiliated party, less (y) the Grantee's
aggregate purchase price for such Option Shares.

         (d)     As used herein, the term "Notional Total Profit" with respect
                                           ---------------------
to any number of Option Shares as to which Grantee may propose to exercise the
Option shall be the Total Profit determined as of the date of the Exercise
Notice assuming that the Option were exercised on such date for such number of
Option Shares and assuming that such Option Shares, together with all other
Option Shares held by Grantee and its affiliates as of such date, were sold for
cash at the closing market price for the Common Stock as of the close of
business on the preceding trading day (less customary brokerage commissions).

    11.  Expenses.  Each party hereto shall pay its own expenses incurred in
         --------
connection with this Agreement, except as otherwise specifically provided
herein.

    12.  Specific Performance.  The Grantor acknowledges that if the Grantor
         --------------------
fails to perform any of its obligations under this Agreement, immediate and
irreparable harm or injury would be caused to the Grantee for which money
damages would not be an adequate remedy.  In such event, the Grantor agrees that
the Grantee shall have the right, in addition to any other rights it may have,
to specific performance of this Agreement.  Accordingly, if the Grantee should
institute an action or proceeding seeking specific enforcement of the provisions
hereof, the Grantor hereby waives the claim or defense that the Grantee has an
adequate remedy at law and hereby agrees not to assert in any such action or
proceeding the claim or defense that such a

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remedy at law exists. The Grantor further agrees to waive any requirement for
the securing or posting of any bond in connection with obtaining any such
equitable relief.

    13.   Notice.  All notices, requests, demands and other communications
          ------
hereunder shall be sent in the manner and to the addresses set forth in the
Merger Agreement.

    14.   Parties in Interest.  Nothing in this Agreement, express or implied,
          -------------------
is intended to confer upon any person other than the Grantor or the Grantee, or
their successors or assigns, any rights or remedies under or by reason of this
Agreement.

    15.   Entire Agreement; Amendments.  This Agreement, together with the
          ----------------------------
Merger Agreement and the other documents referred to therein, contains the
entire agreement between the parties hereto with respect to the subject matter
hereof and supersedes all prior and contemporaneous agreements and
understandings, oral or written, with respect to such transactions.  The terms
of this Agreement may be amended, modified or waived only by an agreement in
writing signed by the party against whom such amendment, modification or waiver
is sought to be enforced.

    16.   Assignment.  No party to this Agreement may assign any of its rights
          ----------
or obligations under this Agreement without the prior written consent of the
other party hereto, except that the Grantee may assign its rights and
obligations hereunder to any direct or indirect wholly-owned subsidiary of the
Grantee (provided that such assignment shall not relieve the Grantee of its
obligations hereunder if such transferee does not perform such obligations).
Any Option Shares sold or transferred by the Grantee to any other person or
entity in compliance with the terms hereof (other than a direct or indirect
wholly-owned subsidiary of the Grantee) shall no longer have the benefit of the
rights provided for herein with respect to such Option Shares (including without
limitation those set forth in Sections 1(d) and 9) and shall no longer be
subject to the restrictions or rights in favor of the Grantor provided for
herein with respect to such Option Shares (including without limitation those
set forth in Sections 7 and 8).

    17.   Headings.  The section headings herein are for convenience only and
          --------
shall not affect the construction of this Agreement.

    18.   Counterparts.  This Agreement may be executed in any number of
          ------------
counterparts, each of which, when executed, shall be deemed to be an original
and all of which together shall constitute one and the same document.

    19.   Governing Law.  This Agreement shall be governed by and construed in
          -------------
accordance with the laws of the State of Delaware (regardless of the laws that
might otherwise govern under applicable Delaware principles of conflicts of
law).

    20.   Survival.  All representations and warranties contained in this
          --------
Agreement shall survive delivery of and payment for the Option Shares.

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<PAGE>

    21.   Severability.  If any term, provision, covenant or restriction of this
          ------------
Agreement is held by a court of competent jurisdiction to be invalid, void or
unenforceable, the remainder of the terms, provisions, covenants and
restrictions of this Agreement shall remain in full force and effect and shall
in no way be affected, impaired or invalidated.

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<PAGE>

     IN WITNESS WHEREOF, the Grantee and the Grantor have caused this Agreement
to be duly executed and delivered on the day and year first above written.

                                    TUBOSCOPE INC.


                                    By:    /s/ John F. Lauletta
                                       -----------------------------------
                                       Name:  John Lauletta
                                       Name:  Chief Executive Officer



                                    VARCO INTERNATIONAL, INC.


                                    By:    /s/ George Boyadjieff
                                       -----------------------------------
                                       Name:  George Boyadjieff
                                       Title:  Chief Executive Officer

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