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                                                                    Exhibit 4.15

                               SECOND AMENDMENT TO
                           COOPER CAMERON CORPORATION
                  SUPPLEMENTAL EXCESS CONTRIBUTION BENEFIT PLAN

     WHEREAS, COOPER CAMERON CORPORATION (the "Company") has heretofore adopted
the COOPER CAMERON CORPORATION SUPPLEMENTAL EXCESS DEFINED CONTRIBUTION PLAN
(the "Plan") for the benefit of the eligible employees of the Employer (as
defined in the Plan); and

     WHEREAS, the Company desires to amend the Plan;

     NOW, THEREFORE, in consideration of the premises, the Plan shall be and is
hereby amended as follows, effective as of July 1, 1998:

     1. The first sentence of Section 5.2 of the Plan shall be deleted and the
following shall be substituted therefor:

     "The benefits payable under the Plan from a Participant's Supplemental
     Matching, Supplemental Basic and Supplemental Post-Tax Accounts shall be
     paid to the Participant, or in the event of his death to his Beneficiary,
     in one lump sum payment; provided, however, the 'Committee' (as defined
     below) may, in its sole discretion, direct that such benefits be paid to or
     on behalf of a Participant to the same recipient(s) in the same manner and
     form as, and coincident with, the payment of the benefits of such
     Participant under the Cooper Cameron Savings Plan. For this purpose, the
     'Committee' shall mean (i) for the period preceding a 'Change of Control'
     (as defined below), the Compensation Committee of the Board, (ii) for the
     two-year period following a 'Change of Control,' the individuals who
     comprised the Compensation Committee of the Board immediately prior to the
     'Change of Control,' acting in their individual capacities, and (iii)
     thereafter, the Committee appointed by the Company. For this purpose, a
     'Change of Control' shall be with respect to the Company and shall have the
     same meaning as such term has in the Cooper Cameron Corporation Long-Term
     Incentive Plan."

     2. Section 10.4 of the Plan shall be deleted and the following shall be
substituted therefor:

          "10.4 Funding. The Plan is intended to constitute an unfunded plan.
     The obligation of an Employer under the Plan to provide a Participant or
     Beneficiary with a benefit constitutes the unsecured promise of such
     Employer to make payments as provided herein, and no person shall have an
     interest in, or a lien or prior claim upon, any property of the Employer.
     The Employer shall establish an irrevocable grantor trust ('Trust') with an
     independent commercial trustee ('Trustee') to provide for the payments of
     the Employer's obligations hereunder. Prior to a Change of Control, the
     funding of the Trust shall be in the sole discretion of the Employer. Upon
     a Change of Control, and prior to or as of

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     the effective date thereof, the Employer shall fund the Trust in an amount
     sufficient to cover all benefit obligations under the Plan as of such date.
     Plan benefits may be paid out of the Employer's general assets or out of
     the Trust. To the extent the Employer transfers assets to the Trust, the
     Trustee shall pay Plan benefits to Participants and Beneficiaries out of
     the Trust in accordance with the terms of the Trust. The Employer shall
     remain the owner of all assets in the Trust, and the assets shall be
     subject to the claims of an Employer's creditors if such Employer ever
     becomes insolvent. For purposes hereof, an Employer shall be considered
     'insolvent' if (i) such Employer is unable to pay its debts as they become
     due or (ii) such Employer is subject to a pending proceeding as a debtor
     under the United States Bankruptcy Code (or any successor federal statute).
     The Employer shall have the duty to inform the Trustee in writing if an
     Employer becomes insolvent. Such notice given under the preceding sentence
     by any party shall satisfy all of the party's duty to give notice. When so
     informed, the Trustee shall suspend payments to the Participants and
     Beneficiaries and hold the assets for the benefit of such Employer's
     general creditors. If the Trustee receives a written allegation that an
     Employer is insolvent, the Trustee shall suspend payments to the
     Participants and Beneficiaries and hold the Trust for the benefit of such
     Employer's general creditors and shall determine within the period
     specified in the Trust whether such Employer is insolvent. If the Trustee
     determines that such Employer is not insolvent, the Trustee shall resume
     payments to the Participants and Beneficiaries. No Participant or
     Beneficiary shall have any preferred claim to, or any beneficial ownership
     interest in, any assets of the Trust."

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

     EXECUTED at Houston, Texas, this 3rd day of September, 1998.

                                                 COOPER CAMERON CORPORATION


                                                 By: /s/ Franklin Myers
                                                     ---------------------------
                                                       Name:  Franklin Myers
                                                       Title: Sr. V.P.

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