[FIDELITY EXPLORATION & PRODUCTION COMPANY LETTERHEAD]


December 6, 2001

Blue Dolphin Exploration Company
801 Travis, Suite 2100
Houston, TX 77002

Re:  Purchase of Back-In Interest on Proved Properties and certain Exploratory
     Properties described as Galveston Block 418 and Ship Shoal Block 85,
     pursuant to Participation Agreement dated July 30, 1999 between Blue
     Dolphin Exploration Company and Fidelity Oil Holdings, Inc.

Gentlemen:

This Letter Agreement memorializes our understanding as to any Back-In Interest
("Back-In Interest") rights Blue Dolphin Exploration Company ("BDEX") owns
pursuant to that certain Participation Agreement by and between Fidelity Oil
Holdings, Inc. ("FOH") and BDEX dated July 30, 1999, in and to the properties
described in Exhibit "A" hereto ("Proved Properties"), and in or to Lease No.
G18921, Block GA 0418, commonly referred to as Galveston Area Block 418 and/or
in and to Lease No. G18005, Block SS 0085, commonly referred to as Ship Shoal
Block 85. The Proved Properties, Galveston Block 418 and Ship Shoal Block 85
are referred to herein collectively as "Back-In Properties."

It is mutually understood and agreed as follows:

1.   Fidelity Exploration & Production Company ("FE&P") is the lawful successor
     in interest to FOH.

2.   BDEX specifically represents and warrants that it has full authority to
     enter into this Letter Agreement and that it has not, except as herein
     specifically provided, transferred, assigned, pledged, hypothecated,
     mortgaged or in any way disposed of or encumbered any Back-In Interest it
     may have or may have had in or to the Back-In Properties or any of them.

3.   For and in consideration of the payment of one million three hundred sixty
     thousand Dollars ($1,360,000), for and in consideration of FE&P's
     assumption of BDEX's proportionate share of the obligation to Den norske
     Bank under that certain Note Purchase Agreement by and between DNB Energy
     Assets, Inc.; Den norske Bank, ASA; BDEX; and FOH dated November 11, 1999,
     and for other valuable consideration, the



[FIDELITY EXPLORATION & PRODUCTION COMPANY LETTERHEAD]

     receipt and sufficiency of which is hereby acknowledged, BDEX does hereby
     forever waive, assign, release, relinquish, remise and quitclaim unto FE&P
     and its successors and assigns, any and all right, title and/or interest it
     may have in or to the Back-In Properties or any of them, including, but not
     limited to, any and all Back-In Interests in or to the Back-In Properties
     or any of them. This assignment, waiver, release, relinquishment and
     quitclaim is made by BDEX without any express, implied, or statutory
     warranty of any kind whatsoever, including, but not limited to, any
     warranty regarding title, (whether for the return of any consideration or
     otherwise), except as set forth in paragraph 2 of this letter.  The payment
     set forth herein shall be made by wire transfer from FE&P to BDEX within 2
     business days of BDEX's execution of this Letter Agreement.

4.   FE&P agrees that it will retain all of its pre-assignment obligations
     associated with the Back-In Properties, including but not limited to the
     obligation to plug and abandon wells and to remove facilities, platforms
     and structures.

5.   The parties expressly recognize and agree that the existence and/or
     validity of any Back-In Interest in or to the Back-In Properties or any of
     them is neither admitted nor denied and this Letter Agreement shall not be
     used or construed to demonstrate the existence or validity of such Back-In
     Interest. However, the parties expressly agree and understand that this
     Letter Agreement may be used and construed and shall constitute an
     irrefutable presumption that BDEX has forever waived and forfeited any
     right to assert the existence or validity of any Back-In Interest in or to
     the Back-In Properties or any of them.

6.   This Letter Agreement shall inure to the benefit of and be binding upon the
     parties and their respective heirs, successors and assigns.

Recognizing this Letter Agreement is a legally binding document and is
contractual in nature and is not a mere recital, please countersign in the space
indicated below if your understanding comports with that stated herein.


                                        Sincerely,


                                        FIDELITY EXPLORATION & PRODUCTION
                                        COMPANY

                                        By: /s/ MICHAEL C. CASKEY
                                            ----------------------------------
                                        Name:   Michael C. Caskey
                                               -------------------------------
                                        Title:  Exec. VP & C.O.O.
                                               -------------------------------

BLUE DOLPHIN EXPLORATION COMPANY

By: /s/ R.B. KELLER                     Date:  December 7, 2001
    ---------------------------------
R.B. Keller, Executive Vice President