EXHIBIT 10.153


                 FIRST AMENDMENT TO AGREEMENT AND PLAN OF MERGER

         This FIRST AMENDMENT TO AGREEMENT AND PLAN OF MERGER ("Amendment"),
dated as of February 17, 2006, by and among Delta Petroleum Corporation, a
Delaware corporation ("Parent") and the surviving entity in a reincorporation
merger with Delta Petroleum Corporation, a Colorado corporation
("Delta-Colorado"), DPCA LLC, a Delaware limited liability company and a wholly
owned subsidiary of Parent ("Subsidiary"), and Castle Energy Corporation, a
Delaware corporation (the "Company"), amends that certain Agreement and Plan of
Merger (the "Merger Agreement"), dated as of November 8, 2005, among
Delta-Colorado, Parent, Subsidiary, and the Company. Terms not otherwise defined
herein shall have the meanings ascribed to them in the Agreement.

                                    RECITALS

         WHEREAS, the Parties desire to amend the Merger Agreement to reflect
the changes specifically set forth below.

                                    AGREEMENT

         NOW, THEREFORE, in accordance with Section 7.4 of the Merger Agreement,
the Parties hereby agree as follows:

                  1. Section 1.7(e) of the Merger Agreement is hereby amended
         and restated in its entirety as follows:

                       "(e) Fractional Shares.

                        (i) No fractional shares of Parent Common Stock shall be
         issued in the Merger, but in lieu thereof each holder of shares of
         Company Common Stock otherwise entitled to a fractional share of Parent
         Common Stock will be entitled to receive, from the Exchange Agent in
         accordance with the provisions of this Section 1.7(e), a cash payment
         of the fair value of such fractional shares of Parent Common Stock. The
         fair value of the fractional shares to be paid shall equal such
         holder's proportionate interest, if any, in the proceeds from the sale
         by Parent or its designees in one or more transactions of shares of
         Parent Common Stock equal to the excess of (x) the aggregate number of
         shares of Parent Common Stock to be delivered to the Exchange Agent by
         Parent pursuant to Section 1.7(a) over (y) the aggregate number of
         whole shares of Parent Common Stock to be distributed to the holders of
         Stock Certificates pursuant to Section 1.7(b) (such excess being herein
         called the "Excess Shares"). As soon as practicable after the Effective
         Time, Parent or its designees, as agent for the holders of the Stock
         Certificates representing shares of Company Common Stock, shall sell
         the Excess Shares at then prevailing prices on the NASDAQ National
         Market System ("NASDAQ") in round lots to the extent
         practicable.

                        (ii) Parent shall deposit the proceeds from the sale of
         the Excess Shares with the Exchange Agent. The Exchange Agent shall
         hold such proceeds in trust for the holders of shares of Company Common
         Stock (the "Common Shares Trust"). The Exchange Agent shall determine
         the portion of the Common Shares Trust to which each holder of shares
         of Company Common Stock shall be entitled, if any, by multiplying the
         amount of the aggregate proceeds comprising the Common Shares Trust by
         a fraction, the numerator of which is the amount of the fractional
         share interest to which such holder of shares of Company Common Stock
         would otherwise be entitled and the denominator of which is the
         aggregate amount of fractional share interests to which all holders of
         shares of Company Common Stock would otherwise be entitled.


                        (iii) As soon as practicable after the determination of
         the amount of cash, if any, to be paid to holders of shares of Company
         Common Stock in lieu of any fractional shares of Parent Common Stock,
         the Exchange Agent shall make available such amounts to such holders of
         shares of Company Common Stock without interest, subject to and in
         accordance with this Section 1.7."

                  2. Section 7.1(b) of the Merger Agreement shall be amended by
         deleting "April 1, 2006" and replacing it with "May 1, 2006".

                  3. Except as modified by this Amendment, the Merger Agreement
         shall remain in full force and effect.

                  4. This Amendment shall be governed by, and construed in
         accordance with, the laws of the State of Delaware regardless of the
         laws that might otherwise govern under applicable principles of
         conflicts of laws thereof.

                  5. This Amendment may be executed in any number of
         counterparts and by different parties hereto in separate counterparts,
         and delivered by means of facsimile transmission or otherwise, each of
         which when so executed and delivered shall be deemed to be an original
         and all of which when taken together shall constitute but one and the
         same agreement. If any party hereto elects to execute and deliver a
         counterpart signature page by means of facsimile transmission, it shall
         deliver an original of such counterpart to each of the other parties
         hereto within ten days of the date hereof, but in no event will the
         failure to do so affect in any way the validity of the facsimile
         signature or its delivery.

                             [Signature page follow]

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                  IN WITNESS WHEREOF, the Company, Parent and Subsidiary have
caused this Amendment to be executed as of the date first written above.

                              DELTA PETROLEUM CORPORATION,
                              A DELAWARE CORPORATION

                              By:  /s/ Roger A. Parker
                                   --------------------------------------------
                              Name:  Roger A. Parker
                              Title: CEO


                              DPCA LLC
                              By: Delta Petroleum Corporation, its Sole Member

                              By:  /s/ Roger A. Parker
                                   --------------------------------------------
                              Name:  Roger A. Parker
                              Title: CEO


                              CASTLE ENERGY CORPORATION

                              By:  /s/ Richard E. Staedtler
                                   --------------------------------------------
                              Name:  Richard E. Staedtler
                              Title:  Chief Executive Officer






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