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                                                                     EXHIBIT 5.1

                       [VINSON & ELKINS L.L.P. LETTERHEAD]


                                November 13, 2000

Ocean Energy, Inc.
1001 Fannin, Suite 1600
Houston, Texas 77002

Ladies and Gentlemen:

         We have acted as counsel for Ocean Energy, Inc., a Texas corporation
(the "Company"), with respect to certain legal matters in connection with the
registration by the Company under the Securities Act of 1933, as amended (the
"Securities Act"), of the offer and sale of up to 1,500,000 shares of Common
Stock, par value $.10 per share (the "Shares") the may be issued pursuant to the
Ocean Energy, Inc. 2001 Employee Stock Purchase Plan (the "Plan").

         In connection with the foregoing, we have examined or are familiar with
(i) the Articles of Incorporation of the Company, as amended, (ii) the Bylaws of
the Company, as amended, (iii) the corporate proceedings with respect to the
issuance of the Shares, (iv) the Registration Statement on Form S-8 filed in
connection with the registration of the Shares (the "Registration Statement")
and the exhibits thereto, and (v) such other certificates, instruments and
documents as we have considered necessary or appropriate for purposes of this
opinion.

         Based upon the foregoing, we are of the opinion that the Shares have
been duly authorized and, when the Shares are issued in accordance with the
provisions of the Plan, will be validly issued and fully paid and
non-assessable.

         The foregoing opinion is limited to the laws of the United States of
America and the State of Texas.

         We hereby consent to the filing of this opinion as an exhibit to the
Registration Statement. In giving this consent, we do not admit that we are
within the category of persons whose consent is required under Section 7 of the
Securities Act and the rules and regulations thereunder.

                                        Very truly yours,

                                        /s/ Vinson & Elkins L.L.P.