UNITED STATES
                       SECURITIES AND EXCHANGE COMMISSION
                             Washington, D.C. 20549


                                  SCHEDULE 13G

                    Under the Securities Exchange Act of 1934
                               (AMENDMENT NO. 4)*

                           ENCORE ACQUISITION COMPANY
--------------------------------------------------------------------------------
                                (Name of Issuer)

                     Common Stock, $0.01 Par Value Per Share
--------------------------------------------------------------------------------
                         (Title of Class of Securities)

                                    29255W100
                                    ---------
                                 (CUSIP Number)

                                December 17, 2004
                                -----------------
                      (Date of Event which Requires Filing
                               of this Statement)


Check the appropriate box to designate the rule pursuant to which this Schedule
                                    is filed:

                                [ ] Rule 13d-1(b)
                                [ ] Rule 13d-1(c)
                                [X]Rule 13d-1(d)


*The remainder of this cover page shall be filled out for a reporting person's
initial filing on this form with respect to the subject class of securities, and
for any subsequent amendment containing information which would alter the
disclosures provided in a prior cover page.

The information required on the remainder of this cover page shall not be deemed
to be "filed" for the purpose of Section 18 of the Securities Exchange Act of
1934 ("Act") or otherwise subject to the liabilities of that section of the Act
but shall be subject to all other provisions of the Act (however, see the
Notes).


                               Page 1 of 8 pages




-------------------                                           ------------------
CUSIP No. 29255W100                   13G                     Page 2 of 8 Pages
-------------------                                           ------------------

---------- ---------------------------------------------------------------------
        1  NAME OF REPORTING PERSON
           I.R.S. IDENTIFICATION NO. OF ABOVE PERSON Warburg, Pincus Equity
           Partners, L.P.
           13-3986317
---------- ---------------------------------------------------------------------
        2  CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP*
                                                                         (a) [ ]

                                                                         (b) [X]

---------- ---------------------------------------------------------------------
        3  SEC USE ONLY

---------- ---------------------------------------------------------------------
        4  CITIZENSHIP OR PLACE OF ORGANIZATION

           Delaware
-------------------- ------ ----------------------------------------------------
                         5  SOLE VOTING POWER

                            0
                     ------ ----------------------------------------------------
     NUMBER OF           6  SHARED VOTING POWER
      SHARES
   BENEFICIALLY             4,964
     OWNED BY
       EACH          ------ ----------------------------------------------------
     REPORTING           7  SOLE DISPOSITIVE POWER
      PERSON
       WITH                 0
                     ------ ----------------------------------------------------
                           8 SHARED DISPOSITIVE POWER

                            4,964
---------- ---------------------------------------------------------------------
        9  AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON

           4,964
---------- ---------------------------------------------------------------------
       10  CHECK BOX IF THE AGGREGATE AMOUNT IN ROW (9) EXCLUDES CERTAIN SHARES

           [ ]
---------- ---------------------------------------------------------------------
       11  PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW (9)

           Less than 1%
---------- ---------------------------------------------------------------------
       12  TYPE OF REPORTING PERSON*

           PN
---------- ---------------------------------------------------------------------
                       *SEE INSTRUCTION BEFORE FILLING OUT


                               Page 2 of 8 Pages




-------------------                                           ------------------
CUSIP No. 29255W100                   13G                     Page 3 of 8 Pages
-------------------                                           ------------------

---------- ---------------------------------------------------------------------
        1  NAME OF REPORTING PERSON
           I.R.S. IDENTIFICATION NO. OF ABOVE PERSON Warburg Pincus & Co.
           13-6358475
---------- ---------------------------------------------------------------------
        2  CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP*
                                                                         (a) [ ]

                                                                         (b) [X]

---------- ---------------------------------------------------------------------
        3  SEC USE ONLY

---------- ---------------------------------------------------------------------
        4  CITIZENSHIP OR PLACE OF ORGANIZATION

           New York
-------------------- ------ ----------------------------------------------------
                         5  SOLE VOTING POWER

                            0
                     ------ ----------------------------------------------------
     NUMBER OF           6  SHARED VOTING POWER
      SHARES
   BENEFICIALLY             4,964
     OWNED BY
       EACH          ------ ----------------------------------------------------
     REPORTING           7  SOLE DISPOSITIVE POWER
      PERSON
       WITH                 0
                     ------ ----------------------------------------------------
                           8 SHARED DISPOSITIVE POWER

                            4,964
---------- ---------------------------------------------------------------------
        9  AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON

           4,964
---------- ---------------------------------------------------------------------
       10  CHECK BOX IF THE AGGREGATE AMOUNT IN ROW (9) EXCLUDES CERTAIN SHARES

           [ ]
---------- ---------------------------------------------------------------------
       11  PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW (9)

           Less than 1%
---------- ---------------------------------------------------------------------
       12  TYPE OF REPORTING PERSON*

           PN
---------- ---------------------------------------------------------------------
                       *SEE INSTRUCTION BEFORE FILLING OUT


                               Page 3 of 8 Pages






-------------------                                           ------------------
CUSIP No. 29255W100                   13G                     Page 4 of 8 Pages
-------------------                                           ------------------

---------- ---------------------------------------------------------------------
        1  NAME OF REPORTING PERSON
           I.R.S. IDENTIFICATION NO. OF ABOVE PERSON
           Warburg Pincus LLC
           13-4069737
---------- ---------------------------------------------------------------------
        2  CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP*
                                                                         (a) [ ]

                                                                         (b) [X]

---------- ---------------------------------------------------------------------
        3  SEC USE ONLY

---------- ---------------------------------------------------------------------
        4  CITIZENSHIP OR PLACE OF ORGANIZATION

           New York
-------------------- ------ ----------------------------------------------------
                         5  SOLE VOTING POWER

                            0
                     ------ ----------------------------------------------------
     NUMBER OF           6  SHARED VOTING POWER
      SHARES
   BENEFICIALLY             4,964
     OWNED BY
       EACH          ------ ----------------------------------------------------
     REPORTING           7  SOLE DISPOSITIVE POWER
      PERSON
       WITH                 0
                     ------ ----------------------------------------------------
                           8 SHARED DISPOSITIVE POWER

                            4,964
---------- ---------------------------------------------------------------------
        9  AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON

           4,964
---------- ---------------------------------------------------------------------
       10  CHECK BOX IF THE AGGREGATE AMOUNT IN ROW (9) EXCLUDES CERTAIN SHARES

           [ ]
---------- ---------------------------------------------------------------------
       11  PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW (9)

           Less than 1%
---------- ---------------------------------------------------------------------
       12  TYPE OF REPORTING PERSON*

           OO
---------- ---------------------------------------------------------------------
                       *SEE INSTRUCTION BEFORE FILLING OUT


                               Page 4 of 8 Pages




Item 1(a)           Name of Issuer:
                    ---------------

                    Encore Acquisition Company

Item 1(b)           Address of Issuer's Principal Executive Offices:
                    ------------------------------------------------

                    777 Main Street, Suite 1400 Fort Worth, TX 76102

Items 2(a)          Name of Person Filing; Address of Principal Business Office:
                    ------------------------------------------------------------

                         Filed by and on behalf of Warburg, Pincus Equity
                    Partners, L.P., a Delaware limited partnership, ("WPEP");
                    Warburg Pincus & Co., a New York general partnership ("WP"),
                    which is the general partner of WPEP; and Warburg Pincus
                    LLC, a New York limited liability company ("WP LLC"), which
                    manages WPEP.

Item 2(b)           Address of Principal Business Office or, if None, Residence
                    -----------------------------------------------------------

                    The business address of each of the foregoing is 466
                    Lexington Avenue, New York, NY 10017

Item 2(c)           Citizenship:
                    ------------

                    WPEP is a Delaware limited partnership, WP is a New York
                    general partnership and WP LLC is a New York limited
                    liability company.

Item 2(d)           Title of Class of Securities:
                    -----------------------------

                    Common Stock, par value $0.01 per share ("Common Stock")

Item 2(e)           CUSIP Number:
                    -------------

                    29255W100

Item 3              If this statement is filed pursuant to ss.ss. 240.13d-1(b)
                    ----------------------------------------------------------
                    or 240.13d-2(b) or (c), check whether the person is filing
                    ----------------------------------------------------------
                    as a:
                    -----

                    Not Applicable

Item 4.             Ownership:
                    ----------


                               Page 5 of 8 pages




                    Warburg, Pincus Equity Partners, L.P.
                    -------------------------------------

                    (a)  Amount beneficially owned: 4,964 shares of Common
                         Stock, as of December 17, 2004.

                    (b)  Percent of Class: Less than 1%

                    (c)  (i) Sole power to vote or direct the vote: -0-

                         (ii) Shared power to vote or direct the vote: 4,964

                         (iii) Sole power to dispose of or direct the
                         disposition of: -0-

                         (iv) Shared power to dispose of or direct the
                         disposition of: 4,964

                    Warburg Pincus & Co.
                    --------------------

                    (a)  Amount beneficially owned: 4,964 shares of Common
                         Stock, as of December 17, 2004.

                    (b)  Percent of Class: Less than 1%

                    (c)  (i) Sole power to vote or direct the vote: -0-

                         (ii) Shared power to vote or direct the vote: 4,964

                         (iii) Sole power to dispose of or direct the
                         disposition of: -0-

                         (iv) Shared power to dispose of or direct the
                         disposition of: 4,964

                    Warburg Pincus LLC
                    ------------------

                    (a)  Amount beneficially owned: 4,964 shares of Common
                         Stock, as of December 17, 2004.

                    (b)  Percent of Class: Less than 1%

                    (c)  (i) Sole power to vote or direct the vote: -0-


                               Page 6 of 8 pages




                         (ii) Shared power to vote or direct the vote: 4,964

                         (iii) Sole power to dispose of or direct the
                         disposition of: -0-

                         (iv) Shared power to dispose of or direct the
                         disposition of: 4,964

Item 5              Ownership of Five Percent or Less of a Class:
                    ---------------------------------------------

                    If this statement is being filed to report the fact that as
                    of the date hereof the reporting person has ceased to be the
                    beneficial owner of more than five percent of the class of
                    securities, check the following. [X]

Item 6              Ownership of More than Five Percent on Behalf of Another
                    --------------------------------------------------------
                    Person:
                    -------

                    Not Applicable

Item 7              Identification and Classification of the Subsidiary Which
                    ---------------------------------------------------------
                    Acquired the Security Being Reported on By the Parent
                    -----------------------------------------------------
                    Holding Company:
                    ----------------

                    Not Applicable

Item 8              Identification and Classification of Members of the Group:
                    ----------------------------------------------------------

                    Not Applicable

Item 9              Notice of Dissolution of Group:
                    -------------------------------

                    Not Applicable

Item 10             Certification:
                    --------------

                         By signing below the reporting persons certify that, to
                    the best of their knowledge and belief, the securities
                    referred to above were not acquired and are not held for the
                    purpose of or with the effect of changing or influencing the
                    control of the issuer of the securities and were not
                    acquired and are not held in connection with or as a
                    participant in any transaction having that purpose or
                    effect.


                               Page 7 of 8 pages




                                    SIGNATURE

     After reasonable inquiry and to the best of my knowledge and belief, I
certify that the information set forth in this statement is true, complete and
correct.

Dated: December 20, 2004

                    WARBURG, PINCUS EQUITY PARTNERS, L.P.
                    By:  Warburg Pincus & Co., General Partner

                    By:  /s/ Scott A. Arenare                           12/20/04
                         ------------------------------------           --------
                    Name:  Scott A. Arenare                               Date
                    Title: Partner


                    WARBURG PINCUS & CO.

                    By:  /s/ Scott A. Arenare                           12/20/04
                         ------------------------------------           --------
                    Name:  Scott A. Arenare                               Date
                    Title: Partner


                    WARBURG PINCUS LLC

                    By:  /s/ Scott A. Arenare                           12/20/04
                         ------------------------------------           --------
                    Name:  Scott A. Arenare                               Date
                    Title: Member


                               Page 8 of 8 pages




                                                                       Exhibit A


Exhibit Index:

     1. Exhibit A - Joint Filing Agreement, dated as of February 7, 2002 (by and
among Warburg, Pincus Equity Partners, L.P., Warburg Pincus & Co. and Warburg
Pincus LLC pursuant to Rule 13d-1(k)(1) under the Securities Exchange Act of
1934) filed with the SEC with Form 13G on February 7, 2002, is incorporated by
reference.

The original statement shall be signed by each person on whose behalf the
statement is filed or his authorized representative. If the statement is signed
on behalf of a person by his authorized representative other than an executive
officer or general partner of the filing person, evidence of the
representative's authority to sign on behalf of such person shall be filed with
the statement, provided, however, that a power of attorney for this purpose
which is already on file with the Commission may be incorporated by reference.
The name and any title of each person who signs the statement shall be typed or
printed beneath his signature.

NOTE: Schedules filed in paper format shall include a signed original and five
copies of the schedule, including all exhibits. SEE Sec. 240.13d-7 for other
parties for whom copies are to be sent.



ATTENTION: INTENTIONAL MISSTATEMENTS OR OMISSIONS OF FACT CONSTITUTE FEDERAL
CRIMINAL VIOLATIONS (SEE 18 U.S.C. 1001)