EXHIBIT 5.1


(BAKER BOTTS L.L.P. LETTERHEAD)



July 10, 2003

074395.0104

Encore Acquisition Company
777 Main Street, Suite 1400
Fort Worth, Texas 76102

Ladies and Gentlemen:

                  As set forth in the Registration Statement on Form S-3 (the
"Registration Statement") to be filed by Encore Acquisition Company, a Delaware
corporation (the "Company"), and the subsidiary guarantors named in Schedule I
hereto (the "Subsidiary Guarantors") with the Securities and Exchange Commission
(the "Commission") under the Securities Act of 1933, as amended (the "Act"),
relating to securities to be issued and sold by the Company and the Subsidiary
Guarantors from time to time pursuant to Rule 415 under the Act for an aggregate
initial offering price not to exceed $400,000,000, certain legal matters in
connection with such securities are being passed upon for you by us. Such
securities include (a) the Company's shares of common stock, par value $.01 per
share ("Common Stock"); (b) the Company's shares of preferred stock, par value
$.01 per share ("Preferred Stock"); (c) the Company's unsecured senior debt
securities (the "Senior Debt Securities"); (d) the Company's unsecured
subordinated debt securities, including the Company's 8 3/8% Senior Subordinated
Notes due 2012 (the "8 3/8% Notes") (collectively, the "Subordinated Debt
Securities" and, together with the Senior Debt Securities, the "Debt
Securities"); and (e) guarantees of the Debt Securities (the "Subsidiary
Guarantees") by the Subsidiary Guarantors. The Common Stock, Preferred Stock,
Debt Securities and Subsidiary Guarantees are collectively referred to herein as
the "Securities."

                  Each series of Debt Securities will be issued:

                  (a) in the case of the Senior Debt Securities, pursuant to an
         indenture to be entered into between the Company, as issuer, and the
         trustee (the "Senior Indenture");

                  (b) in the case of the Subordinated Debt Securities (other
         than the 8 3/8% Notes), pursuant to an indenture to be entered into
         between the Company, as issuer, and the trustee (the "Subordinated
         Indenture"); and

                  (c) in the case of the 8 3/8% Notes, pursuant to the 8 3/8%
         Senior Subordinated Notes Indenture, dated as of June 25, 2002, among
         the Company, the Subsidiary Guarantors and Wells Fargo Bank, N.A., as
         Trustee (the "8 3/8% Notes Indenture" and, together with the Senior
         Indenture and the Subordinated Indenture, the "Indentures").



BAKER BOTTS L.L.P.
Encore Acquisition Company, et. al              2                  July 10, 2003



                  Each Indenture will be supplemented, in connection with the
issuance of each such series, by a supplemental indenture, officers' certificate
or other writing thereunder establishing the form and terms of such series.

                  In our capacity counsel to the Company and the Subsidiary
Guarantors in the connection referred to above, we have examined (a) the
Company's Second Restated Certificate of Incorporation and Bylaws, each as
amended to date (the "Charter Documents"), (b) the articles or certificates of
incorporation, bylaws and agreements of limited partnership, as applicable, of
each of the Subsidiary Guarantors, (c) the form of Senior Indenture, the form of
Subordinated Indenture and the 8 3/8% Notes Indenture (each as filed as an
exhibit to the Registration Statement), and (d) originals, or copies certified
or otherwise identified, of corporate records of the Company and the Subsidiary
Guarantors, including minute books of the Company as furnished to us by the
Company. We have also examined certificates of public officials and of
representatives of the Company, statutes and other instruments and documents as
a basis for the opinions hereinafter expressed. In connection with this opinion,
we have assumed that:

                  (a) the Registration Statement and any amendments thereto
         (including post-effective amendments) will have become effective under
         the Act;

                  (b) a prospectus supplement will have been prepared and filed
         with the Commission describing the Securities offered thereby;

                  (c) all Securities will be offered, issued and sold in
         compliance with applicable federal and state securities laws and in the
         manner stated in the Registration Statement and the appropriate
         prospectus supplement;

                  (d) the Board of Directors of the Company and, if applicable,
         each Subsidiary Guarantor or, to the extent permitted by the charter
         documents and the corporation or limited partnership laws of the
         jurisdiction of incorporation or organization of the Company and, if
         applicable, each Subsidiary Guarantor, a duly constituted and acting
         committee thereof (such Board of Directors or committee being
         hereinafter referred to as the "Board") will have taken all necessary
         corporate action to authorize the issuance of the Securities and any
         other Securities issuable on the conversion, exchange, redemption or
         exercise thereof, and to authorize the terms of the offering and sale
         of such Securities and related matters;

                  (e) a definitive purchase, underwriting or similar agreement
         with respect to any Securities offered will have been duly authorized
         and validly executed and delivered by the Company, the Subsidiary
         Guarantors, if applicable, and the other parties thereto (the "Purchase
         Agreement");

                  (f) any securities issuable upon conversion, exchange,
         redemption or exercise of any Securities being offered will have been
         duly authorized, created and, if appropriate, reserved for issuance
         upon such conversion, exchange, redemption or exercise;




BAKER BOTTS L.L.P.
Encore Acquisition Company, et. al             3                   July 10, 2003



                  (g) all Securities will be delivered in accordance with either
         (a) the provisions of the applicable Purchase Agreement approved by the
         Board upon payment of the consideration therefor provided for therein
         or (b) upon conversion, exchange, redemption or exercise of any other
         Security, in accordance with the terms of such Security or the
         instrument governing such Security providing for such conversion,
         exchange, redemption or exercise as approved by the Board, for the
         consideration approved by the Board;

                  (h) in the case of shares of Common Stock or Preferred Stock,
         certificates representing such shares will have been duly executed,
         countersigned, registered and delivered, or if uncertificated, valid
         book-entry notations will have been made in the share register of the
         Company, in each case in accordance with the provisions of the Charter
         Documents; there will be sufficient shares of Common Stock or Preferred
         Stock authorized under the Charter Documents and not otherwise issued
         or reserved for issuance; and the purchase price therefor payable to
         the Company, or, if such shares are issuable on the conversion,
         exchange, redemption or exercise of another Security, the consideration
         payable to the Company for such conversion, exchange, redemption or
         exercise will not be less than the par value of such shares, in the
         case of shares of Common Stock, or the lesser of such purchase price or
         such consideration, as the case may be, or the amount of such purchase
         price or such consideration, as the case may be, timely determined by
         the Board to constitute the stated capital applicable to such shares,
         in the case of shares of Preferred Stock;

                  (i) in the case of shares of Preferred Stock of any series,
         the Board will have taken all necessary corporate action to designate
         and establish the terms of such series and will have caused a
         certificate of designations respecting such series to be prepared and
         filed with the Secretary of State of the State of Delaware; and

                  (j) in the case of Debt Securities of any series issuable
         under an Indenture:

                  o        if such Debt Securities are Senior Debt Securities,
                           an indenture substantially in the form of the Senior
                           Indenture will have been duly executed and delivered
                           by the Company, the Subsidiary Guarantors, as
                           applicable, and the trustee thereunder;

                  o        if such Debt Securities are Subordinated Debt
                           Securities (other than 83/8% Notes), an indenture
                           substantially in the form of the Subordinated
                           Indenture will have been duly executed and delivered
                           by the Company, the Subsidiary Guarantors, as
                           applicable, and the trustee thereunder;

                  o        in accordance with the terms of the Indenture under
                           which such Debt Securities will be issued, the Board
                           will have taken all necessary corporate action to
                           designate and establish the terms of such series of
                           Debt Securities and such Debt Securities will not
                           include any provision that is unenforceable;




BAKER BOTTS L.L.P.
Encore Acquisition Company, et. al              4                  July 10, 2003



                  o        the Indenture under which such Debt Securities will
                           be issued will have become qualified under the Trust
                           Indenture Act of 1939, as amended; and

                  o        forms of Debt Securities complying with the terms of
                           the Indenture under which such Debt Securities will
                           be issued and evidencing such Debt Securities will
                           have been duly executed, authenticated, issued and
                           delivered in accordance with the provisions of such
                           Indenture.

                  Based upon and subject to the foregoing, we are of the opinion
that:

                  1. The shares of Common Stock and Preferred Stock included in
         the Securities will, when issued, have been duly authorized and validly
         issued and will be fully paid and nonassessable.

                  2. The Debt Securities and the Subsidiary Guarantees included
         in the Securities will, when issued, constitute legal, valid and
         binding obligations of the Company and the Subsidiary Guarantors,
         respectively, enforceable against the Company and the Subsidiary
         Guarantors, respectively, in accordance with their respective terms,
         except as that enforcement is subject to (a) any applicable bankruptcy,
         insolvency, reorganization, moratorium, fraudulent transfer or
         conveyance or other laws relating to or affecting creditors' rights
         generally, (b) general principles of equity (regardless of whether that
         enforceability is considered in a proceeding in equity or at law) and
         (c) any implied covenants of good faith and fair dealing.

                  The opinions set forth above are limited in all respects to
matters of the contract law of the State of New York, the laws of the State of
Texas, the General Corporation Law of the State of Delaware and applicable
federal law. We hereby consent to the filing of this opinion of counsel as
Exhibit 5.1 to the Registration Statement. We also consent to the reference to
our Firm under the heading "Legal Opinions" in the prospectus forming a part of
the Registration Statement. In giving this consent, we do not hereby admit that
we are in the category of persons whose consent is required under Section 7 of
the Act or the rules and regulations of the Commission thereunder.


                                                Very truly yours,

                                                BAKER BOTTS L.L.P.




BAKER BOTTS L.L.P.
Encore Acquisition Company, et. al              5                  July 10, 2003



                                   SCHEDULE I

                              SUBSIDIARY GUARANTORS


<Table>
<Caption>
NAME                                       STATE OF INCORPORATION OR ORGANIZATION
- -------------------------                  --------------------------------------
                                        
Encore Operating, L.P.                     Texas
EAP Operating, Inc.                        Delaware
EAP Properties, Inc.                       Delaware
EAP Energy, Inc.                           Delaware
EAP Energy Services, L.P.                  Texas
</Table>