<PAGE>   1
                                                                    EXHIBIT 10.2



                         COMMERCIAL SECURITY AGREEMENT

<TABLE>
<CAPTION>
  PRINCIPAL       LOAN DATE      MATURITY       LOAN NO.     CALL     COLLATERAL     ACCOUNT        OFFICE     INITIALS
<S>              <C>            <C>           <C>            <C>      <C>            <C>            <C>       <C>
$8,500,000.00    11-09-2000     11-09-2004     0038862700     4A          30           NEW            171

REFERENCES IN THE SHADED AREA ARE FOR LENDER'S USE ONLY AND DO NOT LIMIT THE
APPLICABILITY OF THIS DOCUMENT TO ANY PARTICULAR LOAN OR ITEM.
</TABLE>

<TABLE>
<S>                                                               <C>
Borrower:      MITCHAM INDUSTRIES INC. (TIN: 76-0210849)          Lender:   First Victoria National Bank
               44000 HWY 75 S                                               Main Bank
               HUNTSVILLE, TX 77340                                         P O Box 1338
                                                                            101 South Main
                                                                            Victoria, TX 77902-1338
</TABLE>

THIS COMMERCIAL SECURITY AGREEMENT is entered into between MITCHAM INDUSTRIES
INC. (referred to below as "Grantor"); and First Victoria National Bank
(referred to below as "Lender"). For valuable consideration, Grantor grants to
Lender a security interest in the Collateral to secure the Indebtedness and
agrees that Lender shall have the rights stated in this Agreement with respect
to the Collateral, in addition to all other rights which Lender may have by law.

DEFINITIONS. The following words shall have the following meanings when used in
this Agreement. Terms not otherwise defined in this Agreement shall have the
meanings attributed to such terms in the Uniform Commercial Code. All references
to dollar amounts shall mean amounts in lawful money of the United States of
America.

     AGREEMENT. The word "Agreement" means this Commercial Security Agreement,
     as this Commercial Security Agreement may be amended or modified from time
     to time, together with all exhibits and schedules attached to this
     Commercial Security Agreement from time to time.

     COLLATERAL. The word "Collateral" means the following described property of
     Grantor, whether now owned or hereafter acquired, whether now existing or
     hereafter arising, and wherever located:

          PURCHASE MONEY SECURITY INTEREST ON ALL EQUIPMENT AND INVENTORY
          PURCHASED FROM SERCEL, LTD., GEOSPACE CORP. AND MARK PRODUCTS; AND
          ASSIGNMENT OF ALL LEASES AND REVENUES GENERATED FROM SAID EQUIPMENT
          AND INVENTORY.

     In addition, the word "Collateral" includes all the following, whether now
     owned or hereafter acquired, whether now existing or hereafter arising, and
     wherever located:

          (a) All other accessions, accessories, tools, parts, supplies,
          increases, and additions to and all replacements of and substitutions
          for any property described above.

          (b) All products and produce of any of the property described in this
          Collateral section.

          (c) All accounts, general intangibles, Instruments, rents, monies,
          payments, and all other rights, arising out of a sale, lease, or other
          disposition of any of the property described in this Collateral
          section.

          (d) All proceeds (including insurance proceeds) from the sale,
          destruction, loss, or other disposition of any of the property
          described in this Collateral section.

          (e) All records and data relating to any of the property described in
          this Collateral section, whether in the form of a writing, photograph,
          microfilm, microfiche, or electronic media, together with all of
          Grantors right, title, and interest in and to all computer software
          required to utilize, create, maintain, and process any such records or
          data on electronic media.

     EVENT OF DEFAULT. The words "Event of Default" mean and include without
     limitation any of the Events of Default set forth below in the section
     titled "Events of Default".

     GRANTOR. The word "Grantor" means MITCHAM INDUSTRIES INC., its successors
     and assigns

     GUARANTOR. The word "Guarantor" means and includes without limitation each
     and all of the guarantors, sureties, and accommodation parties in
     connection with the Indebtedness.

     INDEBTEDNESS. The word "Indebtedness" means the indebtedness evidenced by
     the Note, including all principal and earned interest, together with all
     other Indebtedness end costs and expenses for which Grantor is responsible
     under this Agreement or under any of the Related Documents. In addition;
     the word "indebtedness" includes all other obligations, debts and
     liabilities, plus interest thereon, of Grantor, or any one or more of them,
     to Lender, as well as all claims by Lender against Grantor, or any one or
     more of them, whether existing now or later, whether they are voluntary or
     involuntary, due or not due, direct or indirect, absolute or contingent
     liquidated or unliquidated; whether Grantor may be liable individually or
     jointly with others; whether Grantor may be obligated as guarantor, surety,
     accommodation party or otherwise.

     LENDER. The word "Lender" means First Victoria National Bank, its
     successors and assigns.

     NOTE. The word "Note" means the note or credit agreement dated November 9,
     2000, in the principal amount of $8,500,000.00 from MITCHAM INDUSTRIES INC.
     to Lender, together with its renewals of, extensions of, modifications of,
     refinancing of, consolidations of and substitutions for the note or credit
     agreement.

     RELATED DOCUMENTS. The words "Related Documents" mean and include without
     limitation all promissory notes, credit agreements, loan agreements,
     environmental agreements, guaranties, security agreements, mortgages, deeds
     of trust, and all other instruments, agreements and documents, whether now
     or hereafter existing, executed in connection with the indebtedness.

     OBLIGATIONS OF GRANTOR. Grantor warrants and covenants to lender as
     follows:

     ORGANIZATION. Grantor is a corporation which is duly organized, validly
     existing, and in good standing under the laws of the State of Texas.

     AUTHORIZATION. The execution, delivery, and performance of this Agreement
     by Grantor have been duly authorized by all necessary action by Grantor and
     do not conflict with, result in a violation of, or constitute a default
     under (a) any provision of its articles of incorporation or organization,
     or bylaws, or any agreement or other instrument binding upon Grantor or (b)
     any law, governmental regulation, court decree, or order applicable to
     Grantor.

     PERFECTION OF SECURITY INTEREST. Grantor agrees to execute such financing
     statements and to take whatever other actions are requested by Lender to
     perfect and continue Lenders security interest in the Collateral. Upon
     request of Lender, Grantor will deliver to Lender any and all of the
     documents evidencing or constituting the Collateral, and Grantor will note
     Lenders interest upon any and all chattel paper if not delivered to Lender
     for possession by Lender. Grantor hereby appoints Lender as its
     irrevocable attorney-in-fact for the purpose of executing any documents
     necessary to perfect or to continue the security interest granted in this
     Agreement. Lender may at any time, and without further authorization from
     Grantor, file a carbon, photographic or other reproduction of any financing
     statement or of this Agreement for use as a financing statement. Grantor
     will reimburse Lender for all expenses for the perfection and the
     continuation of the perfection of Lender's security interest in the
     Collateral. Grantor promptly will notify Lender before any change in
     Grantor's name including any change to the assumed business names of
     Grantor. This is a continuing Security Agreement and will continue in
     effect even though all or any part of the indebtedness is paid in full and
     even though for a period of time Grantor may not be indebted to Lender.

     NO VIOLATION. The execution and delivery of this Agreement will not violate
     any law or agreement governing Grantor or to which Grantor is a party, and
     its certificate or articles of incorporation and bylaws do not prohibit any
     term or condition of this Agreement.

     ENFORCEABILITY OF COLLATERAL. To the extent the Collateral consists of
     accounts, chattel paper, or general intangibles, the Collateral is
     enforceable in accordance with its terms, is genuine, and complies with
     applicable laws concerning torte, content and manner of preparation and
     execution, and all persons appearing to be obligated on the Collateral have
     authority and capacity to contract and are in fact obligated as they appear
     to be on the Collateral.

     LOCATION OF THE COLLATERAL. Grantor, upon request of Lender, will deliver
     to Lender in forth satisfactory to Lender a schedule of real properties and
     Collateral locations relating to Grantor's operations, including without
     limitation the following: (a) all real property owned or being purchased by
     Grantor, (b) all real property being rented or leased by Grantor, (c) all
     storage facilities owned, rented, leased, or being used by Grantor, and (d)
     all other properties where Collateral is or may be located. Except in the
     ordinary course of its business, Grantor shall not remove the Collateral
     from its existing locations without the prior written consent of Lender.

     REMOVAL OF COLLATERAL. Grantor shall keep the Collateral (or to the extent
     the Collateral consists of intangible property such as accounts, the
     records concerning the collateral) at Grantor's address shown above, or all
     such other locations as are acceptable to Lender. Except in the


<PAGE>   2

11-09-2000                COMMERCIAL SECURITY AGREEMENT                  Page 2
Loan No 0038862700

     records concerning the Collateral) at Grantor's address shown above, or at
     such other locations as are acceptable to Lender. Except in the ordinary
     course of its business, including the sales of inventory, Grantor shall not
     remove the Collateral from its existing locations without the prior written
     consent of Lender. To the extent that the Collateral consists of vehicles,
     or other titled property, Grantor shall not take or permit any action which
     would require application for certificates of title for the vehicles
     outside the State of Texas, without the prior written consent of Lender.

     TRANSACTIONS INVOLVING COLLATERAL. Except for inventory sold or accounts
     collected in the ordinary course of Grantor's business, Grantor shall not
     sell, offer to sell, or otherwise transfer or dispose of the Collateral.
     While Grantor is not in default under this Agreement, Grantor may sell
     inventory, but only in the ordinary course of its business and only to
     buyers who qualify as a buyer in the ordinary course of business. A sale in
     the ordinary course of Grantor's business does not include a transfer in
     partial or total satisfaction of a debt or any bulk sale. Grantor shall not
     pledge, mortgage, encumber or otherwise permit the Collateral to be subject
     to any lien, security interest, encumbrance, or charge, other than the
     security interest provided for in this Agreement, without the prior written
     consent of Lender. This includes security interests even if junior in right
     to the security interests granted under this Agreement. Unless waived by
     Lender, all proceeds from any disposition of the Collateral (for whatever
     reason) shall be held in trust for Lender and shall not be commingled with
     any other funds; provided however, this requirement shall not constitute
     consent by Lender to any sale or other disposition. Upon receipt, Grantor
     shall immediately deliver any such proceeds to Lender.

     TITLE. Grantor represents and warrants to Lender that it holds good and
     marketable title to the Collateral, free and clear of all liens and
     encumbrances except for the lien of this Agreement. No financing statement
     covering any of the Collateral is on file in any public office other than
     those which reflect the security interest created by this Agreement or to
     which Lender has specifically consented. Grantor shall defend Lender's
     rights in the Collateral against the claims and demands of all other
     persons.

     COLLATERAL SCHEDULES AND LOCATIONS. Insofar as the Collateral consists of
     inventory, Grantor shall deliver to Lender, as often as Lender shall
     require, such lists, descriptions, and designations of such Collateral as
     Lender may require to identify the nature, extent, and location of such
     Collateral. Such information shall be submitted for Grantor and each of its
     subsidiaries or related companies.

     MAINTENANCE AND INSPECTION OF COLLATERAL. Grantor shall maintain all
     tangible Collateral in good condition and repair. Grantor will not commit
     or permit damage to or destruction of the Collateral or any part of the
     Collateral. Lender and its designated representatives and agents shall have
     the right at all reasonable times to examine, inspect, and audit the
     Collateral wherever located. Grantor shall immediately notify Lender of all
     cases involving the return, rejection, repossession, loss or damage of or
     to any Collateral; of any request for credit or adjustment or of any other
     dispute arising with respect to the Collateral; and generally of all
     happenings and events affecting the Collateral or the value or the amount
     of the Collateral.

     TAXES, ASSESSMENTS AND LIENS. Grantor will pay when due all taxes,
     assessments and liens upon the Collateral, its use or operation, upon this
     Agreement, upon any promissory note or notes evidencing the Indebtedness,
     or upon any of the other Related Documents. Grantor may withhold any such
     payment or may elect to contest any lien if Grantor is in good faith
     conducting an appropriate proceeding to contest the obligation to pay and
     so long as Lender's Interest in the Collateral is not jeopardized in
     Lender's sole opinion. If the Collateral is subjected to a lien which is
     not discharged within fifteen (15) days, Grantor shall deposit with Lender
     cash, a sufficient corporate surety bond or other security satisfactory to
     Lender in an amount adequate to provide for the discharge of the lien plus
     any interest, costs, attorneys' fees or other charges that could accrue as
     a result of foreclosure or sale of the Collateral. In any contest Grantor
     shall defend itself and Lender and shall satisfy any final adverse judgment
     before enforcement against the Collateral. Grantor shall name Lender as an
     additional obligee under any surety bond furnished in the contest
     proceedings.

     COMPLIANCE WITH GOVERNMENTAL REQUIREMENTS. Grantor shall comply promptly
     with all laws, ordinances, rules and regulations of all governmental
     authorities, now or hereafter in effect, applicable to the ownership,
     production, disposition, or use of the Collateral. Grantor may contest in
     good faith any such law, ordinance or regulation and withhold compliance
     during any proceeding, including appropriate appeals, so long as Lender's
     Interest in the Collateral, in Lender's opinion, is not jeopardized.

     HAZARDOUS SUBSTANCES. Grantor represents and warrants that the Collateral
     never has been, and never will be so long as this Agreement remains a lien
     on the Collateral, used for the generation, manufacture, storage,
     transportation, treatment, disposal, release or threatened release of any
     hazardous waste or substance, as those terms are defined in the
     Comprehensive Environmental Response, Compensation, and Liability Act of
     1980, as amended, 42 U.S.C. Section 9601, et seq. ("CERCLA"), the Superfund
     Amendments and Reauthorization Act of 1986, Pub. L No. 99-499 ("SARA"), the
     Hazardous Materials Transportation Act, 49 U.S.C. Section 1801, et seq.,
     the Resource Conservation and Recovery Act, 42 U.S.C. Section 6901, et
     seq., or other applicable state or Federal laws, rules, or regulations
     adopted pursuant to any of the foregoing. The terms "hazardous waste" and
     "hazardous substance" shall also include, without limitation, petroleum and
     petroleum by-products or any fraction thereof and asbestos. The
     representations and warranties contained herein are based on Grantor's due
     diligence in investigating the Collateral for hazardous wastes and
     substances. Grantor hereby (a) releases and waives any future claims
     against Lender for indemnity or contribution in the event Grantor becomes
     liable for cleanup or other costs under any such laws, and (b) agrees to
     indemnify and hold harmless Lender against any and all claims and losses
     resulting from a breach of this provision of this Agreement. This
     obligation to indemnify shall survive the payment of the Indebtedness and
     the satisfaction of this Agreement.

     MAINTENANCE OF CASUALTY INSURANCE. Grantor shall procure and maintain all
     risks insurance, including without limitation fire, theft and liability
     coverage together with such other insurance as Lender may require with
     respect to the Collateral, in form, amounts, coverages and basis reasonably
     acceptable to Lender. GRANTOR MAY FURNISH THE REQUIRED INSURANCE WHETHER
     THROUGH EXISTING POLICIES OWNED OR CONTROLLED BY GRANTOR OR THROUGH
     EQUIVALENT INSURANCE FROM ANY INSURANCE COMPANY AUTHORIZED TO TRANSACT
     BUSINESS IN THE STATE OF TEXAS. If Grantor fails to provide any required
     insurance or fails to continue such insurance in force, Lender may, but
     shall not be required to, do so at Grantor's expense, and the cost of the
     insurance will be added to the Indebtedness. If any such insurance is
     procured by Lender at a rate or charge not fixed or approved by the State
     Board of Insurance, Grantor will be so notified, and Grantor will have the
     option for five (5) days of furnishing equivalent insurance through any
     insurer authorized to transact business in Texas. Grantor, upon request of
     Lender, will deliver to Lender from time to time the policies or
     certificates of insurance in form satisfactory to Lender, including
     stipulations that coverages will not be cancelled or diminished without at
     least ten (10) days' prior written notice to Lender and not including any
     disclaimer of the insurer's liability for failure to give such a notice.
     Each insurance policy also shall include an endorsement - providing that
     coverage in favor of Lender will not be impaired in any way by any act,
     omission or default of Grantor or any other person. In connection with all
     policies covering assets in which Lender holds or is offered a security
     interest, Grantor will provide Lender with such loss payable or other
     endorsements as Lender may require. If Grantor at any time fails to obtain
     or maintain any insurance as required under this Agreement, Lender may (but
     shall not be obligated to) obtain such insurance as Lender deems
     appropriate, including if it so chooses "single interest insurance," which
     will cover only Lender's interest in the Collateral.

     APPLICATION OF INSURANCE PROCEEDS. Grantor shall promptly notify Lender of
     any loss or damage to the Collateral. Lender may make proof of loss if
     Grantor fails to do so within fifteen (15) days of the casualty. All
     proceeds of any insurance on the Collateral, including accrued proceeds
     thereon, shall be held by Lender as part of the Collateral. If Lender
     consents to repair or replacement of the damaged or destroyed Collateral,
     Lender shall, upon satisfactory proof of expenditure, pay or reimburse
     Grantor from the proceeds for the reasonable cost of repair or restoration.
     If Lender does not consent to repair or replacement of the Collateral,
     Lender shall retain a sufficient amount of the proceeds to pay all of the
     Indebtedness, and shall pay the balance to Grantor. Any proceeds which have
     not been disbursed within six (6) months after their receipt and which
     Grantor has not committed to the repair or restoration of the Collateral
     shall be used to prepay the Indebtedness.

     INSURANCE RESERVES. Lender may require Grantor to maintain with Lender
     reserves for payment of insurance premiums, which reserves shall be created
     by monthly payments from Grantor of a sum estimated by Lender to be
     sufficient to produce, at least fifteen (15) days before the premium due
     date, amounts at least equal to the insurance premiums to be paid. If
     fifteen (15) days before payment is due, the reserve funds are
     insufficient, Grantor shall upon demand pay any deficiency to Lender. The
     reserve funds shall be held by Lender as a general deposit and shall
     constitute a non-interest-bearing account which Lender may satisfy by
     payment of the insurance premiums required to be paid by Grantor as they
     become due. Lender does not hold the reserve funds in trust for Grantor,
     and Lender is not the agent of Grantor for payment of the insurance
     premiums required to be paid by Grantor. The responsibility for the payment
     of premiums shall remain Grantor's sole responsibility.

     INSURANCE REPORTS. Grantor, upon request of Lender, shall furnish to Lender
     reports on each existing policy of insurance showing such information as
     Lender may reasonably request including the following: (a) the name of the
     insurer; (b) the risks insured; (c) the amount of the policy; (d) the
     property insured; (e) the then current value on the basis of which
     insurance has been obtained and the manner of determining that value; and
     (f) the expiration date of the policy. In addition, Grantor shall upon
     request by Lender (however not more often than annually) have an
     independent appraiser satisfactory to Lender determine, as applicable, the
     cash value or replacement cost of the Collateral.

GRANTOR'S RIGHT TO POSSESSION. Until default, Grantor may have possession of the
tangible personal property and beneficial use of all the Collateral and may use
it in any lawful manner not inconsistent with this Agreement or the Related
Documents, provided that Grantor's right to possession and beneficial use shall
not apply to any Collateral where possession of the Collateral by Lender is
required by law to perfect Lender's security interest in such Collateral. If
Lender at any time has possession of any Collateral, whether before or after an
Event of Default, Lender shall be deemed to have exercised reasonable care in
the custody and preservation of the Collateral if Lender takes such action for
that purpose as Grantor shall request or as Lender, in Lender's sole discretion,
shall deem appropriate under the circumstances, but failure to honor any request
by Grantor shall not of itself be deemed to be a failure to exercise reasonable
care. Lender shall not be required to take any steps necessary to preserve any
rights in the Collateral against prior parties, nor to protect, preserve or
maintain any security interest given to secure the Indebtedness.

EXPENDITURES BY 1 LENDER If not discharged [ILLEGIBLE]



<PAGE>   3
11-OS-2000                COMMERCIAL SECURITY AGREEMENT                   Page 3
LOAN NO 00388132700                (CONTINUED)

required to be discharged or paid by Grantor under this Agreement, including
without limitation all taxes, liens, security interests, encumbrances, and other
claims, at any time levied or placed on the Collateral. Lender also may (but
shall not be obligated to) pay all costs for insuring, maintaining and
preserving the Collateral. All such expenditures incurred or paid by Lender for
such purposes will then bear interest at the Note rate from the date incurred or
paid by Lender to the date of repayment by Grantor. All such expenses shall
become a part of the Indebtedness and, at Lender's option, will (a) be payable
on demand, (b) be added to the balance of the Note and be apportioned among and
be payable with any Installment payments to become due during either (i) the
term of any applicable Insurance policy or (ii) the remaining term of the Note,
or (c) be treated as a balloon payment which will be due and payable at the
Note's maturity. This Agreement also will secure payment of these amounts. Such
right shall be in addition to all other rights and remedies to which Lender may
be entitled upon the occurrence of an Event of Default.

EVENTS OF DEFAULT. Each of the following shall constitute an Event of Default
under this Agreement:

     DEFAULT ON INDEBTEDNESS. Failure of Grantor to make any payment when due on
     the Indebtedness.

     OTHER DEFAULTS. Failure of Grantor to comply with or to perform any other
     term, obligation, covenant or condition contained in this Agreement or in
     any of the Related Documents or in any other agreement between Lender and
     Grantor.

     FALSE STATEMENTS. Any warranty, representation or statement made or
     furnished to Lender by or on behalf of Grantor under this Agreement, the
     Note or the Related Documents is false or misleading in any material
     respect, either now or at the time made or furnished.

     DEFECTIVE COLLATERALIZATION. This Agreement or any of the Related Documents
     ceases to be in full force and effect (including failure of any collateral
     documents to create a valid and perfected security interest or lien) at any
     time and for any reason.

     INSOLVENCY. The dissolution or termination of Grantor's existence as a
     going business, the Insolvency of Grantor, the appointment of a receiver
     for any part of Grantor's property, any assignment for the benefit of
     creditors, any type of creditor workout, or the commencement of any
     proceeding under any bankruptcy or Insolvency laws by or against Grantor.

     CREDITOR OR FORFEITURE PROCEEDINGS. Commencement of foreclosure or
     forfeiture proceedings, whether by judicial proceeding, self-help,
     repossession or any other method, by any creditor of Grantor or by any
     governmental agency against the Collateral or any other collateral securing
     the Indebtedness. This includes a garnishment of any of Grantor's deposit
     accounts with Lender. However, this Event of Default shall not apply if
     there is a good faith dispute by Grantor as to the validity or
     reasonableness of the claim which is the basis of the creditor or
     forfeiture proceeding and if Grantor gives Lender written notice of the
     creditor or forfeiture proceeding and deposits with Lender monies or a
     surety bond for the creditor or forfeiture proceeding, in an amount
     determined by Lender, in its sole discretion, as being an adequate reserve
     or bond for the dispute.

     EVENTS AFFECTING GUARANTOR. Any of the preceding events occurs with respect
     to any Guarantor of any of the Indebtedness or such Guarantor dies or
     becomes incompetent Lender, at its option, may, but shall not be required
     to, permit the Guarantor's estate to assume unconditionally the obligations
     arising under the guaranty in a manner satisfactory to Lender, and, in
     doing so, cure the Event of Default.

     ADVERSE CHANGE. A material adverse change occurs in Grantor's financial
     condition.

     RIGHT TO CURE. If any default, other than a Default on Indebtedness, is
     curable and if Grantor has not been given a prior notice of a breach of the
     same provision of this Agreement, it may be cured (and no Event of Default
     will have occurred) if Grantor, after Lender sends written notice demanding
     cure of such default, (a) cures the default within fifteen (15) days; or
     (b), if the cure requires more than fifteen (15) days, immediately
     initiates steps which Lender deems in Lender's sole discretion to be
     sufficient to cure the default and thereafter continues and completes all
     reasonable and necessary steps sufficient to produce compliance as soon as
     reasonably practical.

RIGHTS AND REMEDIES ON DEFAULT. If an Event of Default occurs under this
Agreement, at any time thereafter, Lender shall have all the rights of a secured
party under the Texas Uniform Commercial Code. In addition and without
limitation, Lender may exercise any one or more of the following rights and
remedies:

     ACCELERATE INDEBTEDNESS. Lender may declare the entire Indebtedness
     immediately due and payable, without notice.

     ASSEMBLE COLLATERAL. Lender may require Grantor to deliver to Lender all or
     any portion of the Collateral and any and all certificates of title and
     other documents relating to the Collateral. Lender may require Grantor to
     assemble the Collateral and make it available to Lender at a place to be
     designated by Lender. Lender also shall have full power to enter, provided
     Lender does so without a breach of the peace or a trespass, upon the
     property of Grantor to take possession of and remove the Collateral. If the
     Collateral contains other goods not covered by this Agreement at the time
     of repossession, Grantor agrees Lender may take such other goods, provided
     that Lender makes reasonable efforts to return them to Grantor AFTER
     REPOSSESSION.

     SELL THE COLLATERAL. Lender shall have full power to sell, lease, transfer,
     or otherwise deal with the Collateral or proceeds thereof in its own name
     or that of Grantor. Lender may sell the Collateral at public auction or
     private sale. Unless the Collateral threatens to decline speedily in value
     or is of a type customarily sold on a recognized market, Lender will give
     Grantor reasonable notice of the time after which any private sale or any
     other intended disposition of the Collateral is to be made. The
     requirements of reasonable notice shall be met if such notice is given at
     least ten (10) days before the time of the sale or disposition. All
     expenses relating to the disposition of the Collateral, including without
     limitation the expenses of retaking, holding, insuring, preparing for sale
     and selling the Collateral, shall become a part of the Indebtedness secured
     by this Agreement and shall be payable on demand, with Interest at the Note
     rate from date of expenditure until repaid.

     APPOINT RECEIVER. To the extent permitted by applicable law, Lender shall
     have the following rights and remedies regarding the appointment of a
     receiver: (a) Lender may have a receiver appointed as a matter of right,
     (b) the receiver may be an employee of Lender and may serve without bond,
     and (c) all fees of the receiver and his or her attorney shall become part
     of the Indebtedness secured by this Agreement and shall be payable on
     demand, with Interest at the Note rate from date of expenditure until
     repaid.

     COILED REVENUES, APPLY ACCOUNTS. Lender, either itself or through a
     receiver, may coiled the payments, rents, Income, and revenues from the
     Collateral. Lender may at any time in its discretion transfer any
     Collateral into its own name or that of its nominee and receive the
     payments, rents, income, and revenues therefrom and hold the same as
     security for the Indebtedness or apply it to payment of the Indebtedness in
     such order of preference as Lender may determine. Insofar as the Collateral
     consists of accounts, general intangibles, insurance policies, instruments,
     chattel paper, choices in action, or similar property, Lender may demand,
     collect, receipt for, settle, compromise, adjust, sue for, foreclose, or
     realize on the Collateral as Lender may determine, whether or not
     Indebtedness or Collateral is then due. For these purposes, Lender may, on
     behalf of and in the name of Grantor, receive, open and dispose of mail
     addressed to Grantor; change any address to which mail and payments are to
     be sent; and endorse notes, checks, drafts, money orders, documents of
     title, instruments and items pertaining to payment, shipment, or storage of
     any Collateral. To facilitate collection, Lender may notify account debtors
     and obligors on any Collateral to make payments directly to Lender.

     OBTAIN DEFICIENCY. If Lender chooses to sell any or all of the Collateral,
     Lender may obtain a judgment against Grantor for any deficiency remaining
     on the Indebtedness due to Lender after application of all amounts received
     from the exercise of the rights provided In this Agreement. Grantor shall
     be liable for a deficiency even if the transaction described in this
     subsection is a sale of accounts or chattel paper.

     OTHER RIGHTS AND REMEDIES. Lender shall have all the rights and remedies of
     a secured creditor under the provisions of the Uniform Commercial Code, as
     may be amended from time to time. In addition, Lender shall have and may
     exercise any or all other rights and remedies it may have available at law,
     in equity, or otherwise.

     CUMULATIVE REMEDIES. All of Lender's rights and remedies, whether evidenced
     by this Agreement or the Related Documents or by any other writing, shall
     be cumulative and may be exercised singularly or concurrently. Election by
     Lender to pursue any remedy shall not exclude pursuit of any other remedy,
     and an election to make expenditures or to take action to perform an
     obligation of Grantor under this Agreement, after Grantor's failure to
     perform, shall not affect Lender's right to declare a default and to
     exercise the remedies.

MISCELLANEOUS PROVISIONS. The following miscellaneous provisions are a part of
this Agreement:

     AMENDMENTS. This Agreement, together with any Related Documents,
     constitutes the entire understanding and agreement of the parties as to the
     matters set forth in this Agreement. No alteration of or amendment to this
     Agreement shall be effective unless given in writing and signed by the
     party or parties sought to be charged or bound by the alteration or
     amendment.

     APPLICABLE LAW. This Agreement has been delivered to Lender and accepted by
     Lender in the State of Texas. If there is a lawsuit, Grantor agrees upon
     Lender's request to submit to the jurisdiction of the courts of the State
     of Texas. This Agreement shall be governed by and construed in accordance
     with the laws of the State of Texas and applicable Federal laws.

     ATTORNEYS' FEES AND OTHER COSTS. Lender may hire an attorney to help
     collect the Note if Grantor does not pay, and Grantor will pay Lender's
     reasonable attorneys' fees. Grantor also will pay Lender all other amounts
     actually incurred by Lender as court costs, lawful fees for filing,
     recording, or releasing to any public office any instrument securing the
     Note; the reasonable cost actually expended for repossessing, storing,
     preparing for sale, and selling any security; and fees for noting a lien on
     or transferring a certificate of title to any motor vehicle offered as
     security for the Note, or premiums or identifiable charges received in
     connection with the sale of authorized Insurance.
<PAGE>   4

11-09-2000                    COMMERCIAL SECURITY AGREEMENT              Page 4
Loan No 0038862700                     (Continued)

     CAPTION HEADINGS. Caption headings in this Agreement are for convenience
     purposes only and are not to be used to interpret or define the provisions
     of this Agreement.

     MULTIPLE PARTIES; CORPORATE AUTHORITY. All obligations of Grantor under
     this Agreement shall be joint and several, and all references to Grantor
     shall mean each and every Grantor. This means that each of the persons
     signing below is responsible for all obligations in this Agreement.

     NOTICES. All notices required to be given under this Agreement shall be
     given in writing, may be sent by telefacsimile (unless otherwise required
     by law), and shall be effective when actually delivered or when deposited
     with a nationally recognized overnight courier or deposited in the United
     States mail, first class, postage prepaid, addressed to the party to whom
     the notice is to be given at the address shown above. Any party may change
     its address for notices under this Agreement by giving formal written
     notice to the other parties, specifying that the purpose of the notice is
     to change the party's address. To the extent permitted by applicable law,
     if there is more than one Grantor, notice to any Grantor will constitute
     notice to all Grantors. For notice purposes, Grantor will keep Lender
     informed at all times of Grantor's current address(es).

     POWER OF ATTORNEY. Grantor hereby appoints Lender as its true and lawful
     attorney-in-fact, irrevocably, with full power of substitution to do the
     following: (a) to demand, collect, receive, receipt for, sue and recover
     all sums of money or other property which may now or hereafter become due,
     owing or payable from the Collateral; (b) to execute, sign and endorse any
     and all claims, instruments, receipts, checks, drafts or warrants issued in
     payment for the Collateral; (c) to settle or compromise any and all claims
     arising under the Collateral, and, in the place and stead of Grantor, to
     execute and deliver its release and settlement for the claim; and (d) to
     file any claim or claims or to take any action or institute or take part in
     any proceedings, either in its own name or in the name of Grantor, or
     otherwise, which in the discretion of Lender may seem to be necessary or
     advisable. This power is given as security for the Indebtedness, and the
     authority hereby conferred is and shall be irrevocable and shall remain in
     full force and effect until renounced by Lender.

     SEVERABILITY. If a court of competent jurisdiction finds any provision of
     this Agreement to be invalid or unenforceable as to any person or
     circumstance, such finding shall not render that provision invalid or
     unenforceable as to any other persons or circumstances. If feasible, any
     such offending provision shall be deemed to be modified to be within the
     limits of enforceability or validity; however, if the offending provision
     cannot be so modified, it shall be stricken and all other provisions of
     this Agreement in all other respects shall remain valid and enforceable.

     SUCCESSOR INTERESTS. Subject to the limitations set forth above on transfer
     of the Collateral, this Agreement shall be binding upon and inure to the
     benefit of the parties, their successors and assigns.

     WAIVER. Lender shall not be deemed to have waived any rights under this
     Agreement unless such waiver is given in writing and signed by Lender. No
     delay or omission on the part of Lender in exercising any right shall
     operate as a waiver of such right or any other right. A waiver by Lender of
     a provision of this Agreement shall not prejudice or constitute a waiver of
     Lender's right otherwise to demand strict compliance with that provision or
     any other provision of this Agreement. No prior waiver by Lender, nor any
     course of dealing between Lender and Grantor, shall constitute a waiver of
     any of Lender's rights or of any of Grantor's obligations as to any future
     transactions. Whenever the consent of Lender is required under this
     Agreement, the granting of such consent by Lender in any instance shall not
     constitute continuing consent to subsequent instances where such consent is
     required and in all cases such consent may be granted or withheld in the
     sole discretion of Lender.

LOCK BOX, COLLATERAL ACCOUNT. If Lender requests (whether before or after the
occurrence of an event of default), Grantor will direct each of its account
debtors to make payments directly to a special lock box which is controlled by
Lender. Grantor authorizes and directs Lender to deposit into a special
collateral account, to be maintained and established by Lender, all checks,
drafts and cash payments received in said lock box. All deposits in said
collateral account are designated to be proceeds of collateral and shall not
constitute payment of any obligation. However, Lender may apply collected funds
in the collateral account to the payment of the Indebtedness in such order of
application as Lender may determine, or permit Grantor to withdraw all or any
part of the balance on deposit in said collateral account. If a collateral
account is established, Grantor agrees that it will, immediately upon receipt,
deliver to Lender for deposit into said collateral account, all payments
received by it. Until deposited into said collateral account, all payments
received by Grantor shall be held in trust for Lender and shall not be
commingled with any funds or property of Grantor.

GRANTOR ACKNOWLEDGES HAVING READ ALL THE PROVISIONS OF THIS COMMERCIAL SECURITY
AGREEMENT, AND GRANTOR AGREES TO ITS TERMS. THIS AGREEMENT IS DATED NOVEMBER 9,
2000.

GRANTOR:

BY: /s/ BILLY F MITCHAM, JR
    -----------------------------------
    BILLY F MITCHAM, JR, PRESIDENT