EXHIBIT 5.1


                                       June 2, 2004


Noble Energy, Inc.
100 Glenbough Drive, Suite 100
Houston, Texas  77067

                  Re:  $200,000,000 Aggregate Principal Amount of
                       5.25% Notes Due 2014 of Noble Energy, Inc.

Ladies and Gentlemen:

         We have acted as counsel to Noble Energy, Inc., a Delaware corporation
(the "Company"), in connection with the registration of $200,000,000 aggregate
principal amount of 5.25% Notes due 2014 (the "Exchange Notes") by the Company
on Form S-4 filed with the Securities and Exchange Commission (the "Commission")
on June 2, 2004 (the "Registration Statement"). The Exchange Notes will be
issued pursuant to an indenture (the "Indenture"), dated April 1, 1997, as
amended, between the Company and The Bank of New York Trust Company, N.A., as
successor trustee to U.S. Trust Company of Texas, N.A. (the "Trustee"). The
Exchange Notes will be issued in exchange for the Company's outstanding 5.25%
Notes due 2014 (the "Outstanding Notes") on the terms set forth in the
prospectus contained in the Registration Statement and the Letter of Transmittal
filed as an exhibit thereto (the "Exchange Offer").

         For purposes of this opinion, we have made such legal and factual
examinations and inquiries, including an examination of originals or copies
certified or otherwise identified to our satisfaction, of such documents,
corporate records and other instruments as we have deemed necessary or
appropriate for purposes of this opinion. In our examination, we have assumed
the genuineness of all signatures, the authenticity of all documents submitted
to us as originals, and the conformity to authentic original documents of all
documents submitted to us as copies. We have obtained and relied upon such
certificates and assurances from public officials and we have deemed necessary.

         Based upon and subject to the foregoing and the other matters set forth
herein, it is our opinion that, as of the date hereof, the Exchange Notes have
been duly authorized by all necessary action of the Company, and, subject to the
Registration Statement becoming effective under the Securities Act of 1933, when
duly executed, issued, authenticated and delivered in accordance with the terms
of the Exchange Offer and the Indenture, will be legally valid and


Noble Energy, Inc.
June 2, 2004
Page 2


binding obligations of the Company, enforceable against the Company in
accordance with their terms.

         This opinion is limited by, subject to and based on the following:

         (a)  The opinion relating to the enforceability of the Exchange Notes
              is subject to bankruptcy, insolvency, fraudulent transfer,
              reorganization, moratorium and similar laws of general
              applicability relating to or affecting creditors' rights and to
              general equity principles.

         (b)  We express no opinion as to the enforceability of any provisions
              of the Exchange Notes or the Indenture providing for (i) the
              waiver of a right of immunity, stay, extension, or usury laws, or
              (ii) any party's consent to jurisdiction or venue.

         (c)  This opinion is limited in all respects to the laws of the State
              of Texas, the General Corporation Law of the State of Delaware,
              the federal laws of the United States, and, only as to the
              enforceability of the Exchange Notes, the laws of the State of New
              York.

         To the extent that the obligations of the Company under the Exchange
Notes may be dependent upon such matters, we have assumed for purposes of this
opinion that (i) the Trustee is validly existing and in good standing under the
laws of its jurisdiction of organization; (ii) the Trustee has been duly
qualified to engage in the activities contemplated in the Indenture; (iii) the
Trustee is in compliance generally, and with respect to acting as Trustee under
the Indenture, with all applicable laws and regulations; (iv) the Indenture has
been duly authorized, executed and delivered by the Trustee and constitutes the
legally valid and binding obligation of the Trustee, enforceable against the
Trustee in accordance with its terms; and (v) the Trustee has the requisite
organizational and other power and authority to perform its obligations under
the Indenture.

         We hereby consent to the filing of this opinion as an exhibit to the
Registration Statement and to the reference to our firm's name under the heading
"Legal Matters" in the prospectus contained therein.


                                           Very truly yours,


                                           /s/ Thompson & Knight LLP
                                           -------------------------
                                           Thompson & Knight LLP