FIRST AMENDMENT TO PURCHASE AND SALE AGREEMENT

EXHIBIT 2.6

                                 FIRST AMENDMENT
                         TO PURCHASE AND SALE AGREEMENT

     THIS FIRST AMENDMENT TO PURCHASE AND SALE AGREEMENT (this "Amendment")
dated as of December 1, 2006, is entered into by SWEPI LP, a Delaware limited
partnership ("SELLER") and PACIFIC ENERGY RESOURCES LTD., a Delaware corporation
("BUYER").

                                    RECITALS

     A. Pursuant to that certain Purchase and Sale Agreement dated as of
November 13, 2006, between Seller and Buyer (as the same may be, from time to
time, amended, the "PURCHASE AGREEMENT"), Buyer agreed to purchase certain oil
and gas interests and related real and personal property from Seller, and Seller
agreed to sell such interests and related property to Buyer.

     B. Seller and Buyer desire to amend certain provisions of the Purchase
Agreement.

     C. Capitalized terms used in this Amendment but not specifically defined
herein shall have the respective meanings given to them in the Purchase
Agreement.

                                    AGREEMENT

     NOW, THEREFORE, in consideration of the foregoing recitals, the agreements
set forth herein and for other good and valuable consideration, the receipt and
sufficiency of which are hereby acknowledged, Seller and Buyer hereby agree as
follows:

     1. Modification of Purchase Agreement. Seller and Buyer hereby agree to
amend the Purchase Agreement as follows:

          (a) SECTION 10.01(c)(i) of the Purchase Agreement is amended by
     deleting the date "December 1, 2006" and inserting in its place the date
     "December 8, 2006."

     2. Continuing Force and Effect. Except as amended hereby, the Purchase
Agreement shall remain unmodified and in full force and effect. The Parties
hereby ratify and confirm the Purchase Agreement, as amended concurrently
herewith.

     3. Counterparts. This Amendment may be executed in any number of
counterparts, each of which shall be deemed to be an original, and all of such
counterparts shall constitute one agreement. To facilitate execution of this
Amendment, the Parties may execute and exchange facsimile counterparts of the
signature pages, and facsimile counterparts shall serve as originals.


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     4. GOVERNING LAW. THIS AMENDMENT SHALL BE GOVERNED AND CONSTRUED IN
ACCORDANCE WITH THE LAWS OF THE STATE OF CALIFORNIA, EXCLUDING ANY CONFLICT OF
LAW PROVISIONS THEREOF.

     5. Entire Agreement. The Purchase Agreement, as amended hereby, constitutes
the entire understanding between the Buyer and Seller with respect to the
subject matter thereof and hereof, superseding all negotiations, prior
discussions, correspondence, offering materials, maps and prior agreements and
understandings relating to such subject matter, whether oral or written.

                      [signatures begin on following page]


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     IN WITNESS WHEREOF, the duly authorized representatives of Seller and Buyer
have executed this Amendment as of the date fist above written.

                                        Seller:

                                        SWEPI LP, a Delaware limited partnership


                                        By: /s/ X.X. Xxxxxxx
                                            ------------------------------------
                                        Name: X.X. XXXXXXX
                                        Title: ATTORNEY-IN-FACT


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                                        Buyer:

                                        PACIFIC ENERGY RESOURCES LTD., a
                                        Delaware corporation


                                        By: /s/ Xxxxxx Xxxxx
                                            ------------------------------------
                                        Name: XXXXXX XXXXX
                                        Title: PRESIDENT


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