EXHIBIT 10.23.1

                         Amendment to Purchase Contract

RWG Energy, Inc. ("Seller") and Targa North Texas LP, successor-in-interest to
Targa Midstream Services Limited Partnership ("Buyer") entered into a Gas
Purchase Contract dated January 30, 1998 ("the Contract").

Seller and Buyer now wish to amend the Contract, as set forth herein.

Now therefore, in consideration of the premises and other valuable
consideration, Seller and Buyer agree as follows:

The provision entitled "ARTICLE X - COMPENSATION TO SELLER", Subsections A.
Plant Products, B. Residue Gas and (paragraph) C. is hereby deleted in its
entirety and replaced with the following:

                       ARTICLE X - COMPENSATION TO SELLER

Buyer shall pay to Seller as total compensation for the Gas delivered hereunder
the sum of the values computed in accordance with subsections A. and B. of this
Article.

A.   Plant Products - An amount equal to Seller's allocated gallons of Plant
     Products (determined as provided in the Allocation of Plant Products
     provision hereof) times * times the "current weighted average net sales
     price" of such Plant Products.

     The "current weighted average net sales price" of each Plant Product shall
     be determined by dividing the total gallons of such product produced and
     sold during the accounting period involved into the "Net proceeds f.o.b.
     Plant" received from sales of such Plant Products for such period by Buyer.

     "Net proceeds f.o.b. Plant" shall be the total gross proceeds received by
     Buyer from the sale of each Plant Product during each accounting period
     less any charges for tank car rental, sales commissions, taxes, pipeline
     transportation costs, and similar costs and expenses incurred or made in
     connection with the sale, transportation, and delivery of such Plant
     Product.

     When Buyer sells Plant Products through its own marketing organization, the
     sales commissions shall be commensurate with the current commission being
     charged in the industry by independent brokers handling like products;

B.   Residue Gas - An amount equal to * of the net proceeds received from the
     sale of such Residue Gas.

     The volume of "Residue Gas" shall be determined by application of the
     Allocation of Residue Gas provision hereof. "Net Proceeds" as herein used
     shall mean the total gross proceeds received by Buyer from the sale of
     surplus Residue Gas during each accounting period less any costs incurred
     by Buyer for transporting or compression required to market the Residue
     Gas.

The effective date of this Amendment is April 1, 2006.

All other provisions of the Contract shall remain in full force and effect.


Accepted and Agreed to:                      Accepted and Agreed to:

RWG Energy, Inc.                             Targa North Texas LP
                                             By:  Its General Partner,
                                                  Targa North Texas GP LLC

By:  /s/Larry G. Rampey                      By:  /s/Clark White

Printed Name:  Larry G. Rampey               Printed Name:  Clark White

Title:  Sr. V.P. Operations                  Title:  Vice President

Date:  May 10, 2006                          Date:  May 8, 2006

Owner's Federal Tax ID Number:               Company's Federal Tax ID Number:
           020685292                                      20-4036176

Address:                                     Address:

Suite 650                                    1000 Louisiana Suite 4700
5100 Skelly Drive                            Houston, TX  77002
Tulsa, OK  74135



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* Confidential information has been omitted and filed separately with the
Securities and Exchange Commission.