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                                                                    EXHIBIT 99.8

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                              OCEAN ENERGY, INC.,
                            A DELAWARE CORPORATION,
                             SUCCESSOR BY MERGER TO
                               OCEAN ENERGY, INC.
                              A TEXAS CORPORATION,
                                   AS ISSUER,

                              OCEAN ENERGY, INC.,
                            A LOUISIANA CORPORATION,
                            AS SUBSIDIARY GUARANTOR,

                                      AND

                             THE BANK OF NEW YORK,
                                   AS TRUSTEE

                              --------------------

                         SECOND SUPPLEMENTAL INDENTURE

                            DATED AS OF MAY 9, 2001

                                       TO

                         SENIOR SUBORDINATED INDENTURE

                           DATED AS OF JULY 15, 1993

                              --------------------

                   8 5/8% SENIOR SUBORDINATED NOTES DUE 2005





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                          SECOND SUPPLEMENTAL INDENTURE

         SECOND SUPPLEMENTAL INDENTURE (this "SUPPLEMENTAL INDENTURE"), dated as
of May 9, 2001, by and among Ocean Energy, Inc., a Delaware corporation (the
"COMPANY"), as successor by merger to Ocean Energy, Inc. (formerly known as
Seagull Energy Corporation), a Texas corporation ("OLD OCEAN"), Ocean Energy,
Inc., a Louisiana corporation and wholly-owned subsidiary of the Company ("OEI
SUB"), and The Bank of New York, a New York banking corporation, as trustee (the
"TRUSTEE").

                                    RECITALS

         WHEREAS, Old Ocean, as Issuer, executed and delivered to the Trustee
the Senior Subordinated Indenture, dated as of July 15, 1993 (the "SENIOR
SUBORDINATED INDENTURE"), providing for the issuance of an aggregate principal
amount of $150,000,000 of 8 5/8% Senior Subordinated Notes due 2005; and

         WHEREAS, Old Ocean, as issuer, and OEI Sub, as subsidiary guarantor,
delivered the First Supplemental Indenture, dated as of March 30, 1999 (the
"FIRST SUPPLEMENTAL INDENTURE;" together with the Senior Subordinated Indenture,
the "INDENTURE"), to the Trustee, providing for the creation of a Subsidiary
Guarantee and changing the name of the Issuer from Seagull Energy Corporation to
Old Ocean; and

         WHEREAS, under the terms of the Agreement and Plan of Merger, dated as
of March 30, 2001, by and between Old Ocean and the Company (the "MERGER
AGREEMENT"), Old Ocean has merged with and into the Company, with the Company as
the surviving entity (the "MERGER"); and

         WHEREAS, OEI Sub is a wholly owned subsidiary of the Company and acts
as a Subsidiary Guarantor under Section 14 of the Indenture; and

         WHEREAS, under Section 8.1(b) of the Indenture, the Issuer, when
authorized by a resolution of its Board of Directors, and the Trustee may from
time to time and at any time enter into an indenture or supplemental indenture
to evidence the succession of another corporation to the Issuer, or successive
successions, and the assumption by the successor corporation of the covenants,
agreements and obligations of the Issuer; and

         WHEREAS, in accordance with Section 9.1(c) of the Indenture, the
Company, as successor by merger to Old Ocean, must execute and deliver a
supplemental indenture, in a form satisfactory to the Trustee, to the Trustee,
expressly assuming the due and punctual payment of the principal of and
interest, if any, on all the Securities, according to their tenor, and the due
and punctual performance and observance of all of the covenants and conditions
of this Indenture to be performed by the Issuer.

         NOW THEREFORE, in consideration of the foregoing and for other good and
valuable consideration, the receipt of which is hereby acknowledged, the
Company, OEI Sub and the Trustee mutually covenant and agree for the equal and
ratable benefit of the Holders as follows:
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         1. Definitions. Capitalized terms used herein without definition have
the meanings assigned to them in the Indenture. For all purposes of this
Supplemental Indenture, except as otherwise herein expressly provided or unless
the context otherwise requires, the words "herein," "hereof" and "hereby" and
other words of similar import refer to this Supplemental Indenture as a whole
and not to any particular section hereof.

         2. Assumption by the Company. The Company hereby (i) expressly assumes
all Old Ocean's obligations for the prompt and punctual payment of the principal
of and interest, if any, on the Securities , according to their tenor, and the
due and punctual performance and observance of all of the covenants and
conditions of the Indenture to be performed by Old Ocean, and (ii) succeeds to,
and becomes substituted for, and may exercise every right and power of Old Ocean
under the Indenture with the same effect as if the Company had originally been
named as the issuer of the Securities under the Indenture.

         3. Change of Corporate Name. Any and all references in the Indenture
and the Securities to Seagull Energy Corporation, a Texas corporation, or Ocean
Energy, Inc., a Texas corporation, or the "Issuer," will be deemed henceforth to
refer to Ocean Energy, Inc., a Delaware corporation.

         4. Ratification of Indenture; Supplemental Indentures Part of
Indenture. Except as expressly amended hereby, the Indenture is in all respects
ratified and confirmed and all the terms, conditions and provisions thereof will
remain in full force and effect. This Supplemental Indenture forms a part of the
Indenture for all purposes, and every Holder of Securities heretofore or
hereafter authenticated and delivered will be bound hereby. All prior
designations by Old Ocean of "Restricted Subsidiaries," "Subsidiary Guarantors,"
or "Unrestricted Subsidiaries" or other designations shall continue in effect
until changed by the Company in accordance with the Indenture as modified by
this Supplemental Indenture.

         5. Trustee Makes No Representation. The Trustee makes no representation
as to the validity or sufficiency of this Supplemental Indenture.

         6. Counterparts. The parties may sign any number of copies of this
Supplemental Indenture. Each signed copy will be an original, but all of them
together represent the same agreement.

         7. Headings. The Section headings herein are for convenience only and
do not affect the construction hereof.

                            [Signature Page Follows]




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         IN WITNESS WHEREOF, the parties hereto have caused this Supplemental
Indenture to be duly executed as of the date first above written.

                                   OCEAN ENERGY, INC., a Delaware corporation


                                   By:      /s/ Stephen A. Thorington
                                         ---------------------------------------
                                         Stephen A. Thorington,
                                         Senior Vice President - Finance,
                                         Treasury & Corporate Development


                                   THE BANK OF NEW YORK, as Trustee


                                   By:      /s/ Walter N. Gitlin
                                         ---------------------------------------
                                         Name:  Walter N. Gitlin



                                   OCEAN ENERGY, INC., a Louisiana corporation


                                   By:      /s/ William L. Transier
                                         ---------------------------------------
                                         Name:  William L. Transier
                                         Title: Executive Vice President and
                                                Chief Financial Officer




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