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                                                                    EXHIBIT 10.3
                               FIRST AMENDMENT TO
                                CORE LABORATORIES
                     SUPPLEMENTAL EXECUTIVE RETIREMENT PLAN


         WHEREAS, CORE LABORATORIES N.V. and its participating affiliates (the
"Company") has heretofore adopted the CORE LABORATORIES SUPPLEMENTAL EXECUTIVE
RETIREMENT PLAN (the "Plan") for the benefit of certain employees and
independent directors of the Company; and

         WHEREAS, the Company desires to amend the Plan in certain respects;

         NOW, THEREFORE, the Plan shall be amended as follows, effective as of
July 29, 1999:

         1. The following new Section 1.1(6A) shall be added immediately after
Section 1.1(6) of the Plan:

         "(6A) DESIGNATED BENEFICIARY: A Participant's beneficiary or
beneficiaries determined in accordance with Section 1.5."

         2. Section 1.1(13) of the Plan shall be deleted and the following shall
be substituted therefor:

         "(13) INTENTIONALLY OMITTED."

         3. The following new Section 1.5 shall be added immediately after
Section 1.4 of the Plan:

            "1.5 Each Participant shall have the right to designate the
         beneficiary or beneficiaries to receive payment of his benefit in the
         event of his death. Each such designation shall be made in writing
         filed with the Committee by the Participant. Any such designation may
         be changed at any time by such Participant by execution and filing of a
         new designation in accordance with this Section. If no beneficiary
         designation is on file with the Committee at the time of the death of
         the Participant or if such designation is not effective for any reason
         as determined by the Committee, the designated beneficiary or
         beneficiaries to receive such death benefit shall be as follows:

                 (1) If a Participant leaves a surviving spouse, his designated
            beneficiary shall be such surviving spouse; and

                 (2) If a Participant leaves no surviving spouse, his designated
            beneficiary shall be (A) such Participant's executor or
            administrator or (B) his heirs at law if there is no administration
            of such Participant's estate.


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         Notwithstanding the preceding provisions of this Section and to the
         extent not prohibited by state or federal law, if a Participant is
         divorced from his spouse and at the time of his death is not remarried
         to the person from whom he was divorced, any designation of such
         divorced spouse as his beneficiary under the Plan filed prior to the
         divorce shall be null and void unless the contrary is expressly stated
         in writing filed with the Committee by the Participant. The interest of
         such divorced spouse failing hereunder shall vest in the persons
         specified in the preceding provisions of this Section as if such
         divorced spouse was not designated as a beneficiary by the
         Participant."

         4. Section 4.2 of the Plan shall be deleted and the following shall be
substituted therefor:

            "4.2 In the event a Participant dies on or after his Retirement Date
         and prior to receiving fifteen annual installment payments of his
         Retirement Benefit, such Participant's Retirement Benefit shall be
         paid, or continue to be paid, to his Designated Beneficiary in annual
         installments at the same time and in the same amount as such Retirement
         Benefit would have been paid to such Participant had his death not
         occurred, and such Retirement Benefit installments shall continue
         through the Anniversary Date upon which such deceased Participant would
         have received the fifteenth Retirement Benefit installment. In the
         event of the death of a Participant's Designated Beneficiary prior to
         the payment of the fifteenth Retirement Benefit installment, such
         Designated Beneficiary's share of any remaining installments of such
         Participant's Retirement Benefit shall be paid to such Designated
         Beneficiary's estate at the same time, in the same amount, and for the
         same period of time such Retirement Benefit would have been paid to
         such Designated Beneficiary had his or her death not occurred. All
         payments of a deceased Participant's Retirement Benefit pursuant to
         this Section 4.2 shall cease upon the date of payment of what would
         have been the deceased Participant's fifteenth Retirement Benefit
         installment."

         5. The term "Surviving Spouse" shall be deleted in each place such term
appears in Sections 4.3 and 5.4 of the Plan, and the term "Designated
Beneficiary" shall be substituted therefor in each such place.

         6. Sections 5.2 and 5.3 of the Plan shall be deleted and the following
shall be substituted therefor:

            "5.2 In the event a Participant (other than Stephen D. Weinroth)
         dies prior to his Retirement Date, a Death Benefit shall be paid to
         such Participant's Designated Beneficiary pursuant to this Section 5.2.
         The Death Benefit shall consist of fifteen annual lump sum payments of





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         $225,000 each. The initial payment of such Participant's Death Benefit
         shall be paid to his Designated Beneficiary as soon as administratively
         practicable after such Participant's death, and a payment of $225,000
         shall be paid to such Designated Beneficiary on each of the fourteen
         subsequent anniversaries of the Participant's death thereafter. In the
         event of the death of a Designated Beneficiary prior to the payment of
         fifteen Death Benefit installments, such Designated Beneficiary's share
         of any remaining installments of the Participant's Death Benefit shall
         be paid to such Designated Beneficiary's estate at the same time, in
         the same amount, and for the same period of time such Death Benefit
         would have been paid to such Designated Beneficiary had his or her
         death not occurred. All Death Benefit payments pursuant to this Section
         5.2 shall cease upon the payment of the fifteenth annual installment of
         such Death Benefit.

            5.3 In the event that Participant Stephen D. Weinroth dies prior to
         his Retirement Date, a Death Benefit shall be paid to his Designated
         Beneficiary pursuant to this Section 5.3. The Death Benefit shall
         consist of fifteen annual lump sum payments of $225,000 each. The
         initial payment of such Participant's Death Benefit shall be paid to
         his Designated Beneficiary on (or as soon as administratively
         practicable after) the date that would have been such deceased
         Participant's Retirement Date, and a payment of $225,000 shall be paid
         to such Designated Beneficiary on each of the fourteen subsequent
         Anniversary Dates thereafter. In the event of the death of a Designated
         Beneficiary prior to the payment of fifteen Death Benefit installments
         pursuant to this Section 5.3, such Designated Beneficiary's share of
         any remaining installments of the Participant's Death Benefit shall be
         paid to such Designated Beneficiary's estate at the same time, in the
         same amount, and for the same period of time such Death Benefit would
         have been paid to such Designated Beneficiary had his or her death not
         occurred. All Death Benefit payments pursuant to this Section 5.3 shall
         cease upon the payment of the fifteenth annual installment of such
         Death Benefit."

         7. Section 6.2 of the Plan shall be deleted and the following shall be
substituted therefor:

            "6.2 In the event a Participant's services or employment with the
         Company is terminated for Cause, all benefits payable under the Plan to
         such Participant or to his Designated Beneficiary shall be forfeited,
         and neither the Participant nor any Designated Beneficiary of the
         Participant shall be entitled to receive any benefit under the Plan."

         8. The term "Surviving Spouses" shall be deleted in each place such
term appears in Section 8.3 of the Plan, and the term "Designated Beneficiaries"
shall be substituted therefor in each such place.

         9. The parenthetical in the second sentence of Section 9.2 of the Plan
shall be deleted and the following shall be substituted therefor:



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         "(or, in the case of a deceased Participant, such Participant's
         Designated Beneficiary any payable but unpaid Death Benefit or
         Retirement Benefit)"

         10. As amended hereby, the Plan is specifically ratified and
reaffirmed.


         EXECUTED on this _____ day of ______________________, 1999.

                                               CORE LABORATORIES N.V.



                                               BY:
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                                                  NAME:
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                                                  TITLE:
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