Exhibit 10.26


                                               Cinergy Marketing & Trading, LP
                                               1100 Louisiana Street, Suite 4900
                                               Houston, TX 77002 Tel
                                               713.393.6800 Fax 713.571.1741


                                  May 23, 2003




Kerr-McGee Oil & Gas Corporation
Kerr-McGee Oil & Gas Onshore LP
Orxy Marketing Limited Partnership
16666 Northchase
Houston, Texas 77060


Gentlemen:


     Reference is hereby made to that certain  Amended and Restated Gas Purchase
Agreement  dated July 1, 1998,  as amended,  by and among  Kerr-McGee  Oil & Gas
Corporation,  Kerr-McGee  Oil & Gas  Onshore  LP,  and  Orxy  Marketing  Limited
Partnership  (collectively,  "Seller")  and  Cinergy  Marketing  &  Trading,  LP
("Buyer") (the "Agreement").  In consideration of the mutual covenants contained
herein,  Seller and Buyer agree to amend the  Agreement  in the manner set forth
herein.

1. Seller has a supply of gas that is produced from the BoomVang  Nansen area in
the Gulf of Mexico that is currently dedicated to the Agreement (the "BVN Gas"),
and  Seller  and Buyer  agree to amend the  Agreement  to  provide  for  special
treatment for the first 100,000  MMBtu's of BVN Gas (the "Base BVN Gas") that is
produced  each Day of the period  commencing on the Start Date and ending on the
third  anniversary of the Start Date (the "Limited Term").  The Start Date shall
be the  first  day of the Month  following  the  Month in which  the  Facilities
Completion  Date, as defined  hereinbelow,  occurs.  It is anticipated  that the
Start  Date will be  September  1,  2003.  Exhibit A to the  Agreement  shall be
restructured to provide a separate line item for the Base BVN Gas, which will be
referred to on the Exhibit A as the Aggregation  Area noted as "Base BVN" with a
corresponding Delivery Point noted as the "Markham PLT-Crosstex."

2. During the Limited Term,  Seller shall sell and Buyer shall purchase the Base
BVN Gas in accordance  with the terms and conditions of the Agreement as amended
by this Letter  Agreement.  During each Day of the Limited Term, Seller shall be
deemed  to have  designated  100,000  MMBtu's  of gas  per  Day in its  Seller's
Estimate for the Base BVN Gas, 75% of the daily Base BVN Gas, or 75,000  MMBtu's
per Day, as Baseload  Gas, and the  remaining  25% of the daily Base BVN Gas, or
25,000 MMBtu's per Day, as Swing Gas. Consequently, Seller's Baseload Designated
Percentage shall be 75%, and the Seller's Swing  Designated  Percentage shall be
25%, of the Base BVN Gas, irrespective of any Baseload Designated Percentages or
Swing Designated  Percentages specified by Seller from time to time for Seller's
remaining gas, including the remaining BoomVang Nansen gas above 100,000 MMBtu's
per day, dedicated to the Agreement.

3. The Contract  Price for the Base BVN Gas (i.e.,  the  Baseload  Price and the
Swing  Price)  shall  be  calculated  in  accordance  with  Section  7.1  of the
Agreement,  based on  information  contained in Exhibit A from time to time, and
calculated utilizing,  as a deduction, an initial Monthly Index Price Adjustment
for the Baseload Price and an initial Daily Index Price Adjustment for the Swing
Price  each  equal to $0.11  per  MMBtu  plus the  Recoupment  Fee per MMBtu (as
defined hereinbelow). If and at such time as Payout, as defined hereinbelow, has
occurred,  the  Recoupment  Fee shall be eliminated  during the remainder of the
Limited  Term.  Effective  September  1, 2003,  the current form of Exhibit "A,"
however designated, that is in effect immediately prior to September 1, 2003, is
hereby  amended by deleting  the same and  substituting  therefore  the attached
Exhibit  "A:SEP-03," a copy of which is attached  hereto as Attachment "A." Each
reference in the  Agreement to the phrase,  "Exhibit A," shall be a reference to
such form Exhibit "A:SEP-03."

4. a. Seller and Buyer  acknowledge  that in order to facilitate the flow of the
Base BVN Gas,  Buyer is causing (i)  Crosstex Gas Company  ("Crosstex"),  Kinder
Morgan Tejas Pipeline ("Kinder"), and Transcontinental Gas Pipe Line Corporation
("Transco") to install several hundred feet of pipeline to connect Transco's and
Crosstex'  existing  pipeline systems in Matagorda  County,  Texas near Williams
Field  Services  Company's  Markham Gas  Processing  Plant and related  metering
facilities  (this is the location of the Markham  PLT-Crosstex  Delivery Point),
and (ii)  Crosstex  and Kinder to  construct a new  interconnect  between  their
existing  pipeline  systems in  Matagorda  County,  Texas and  related  metering
facilities.  Buyer shall notify Seller of the Facilities  Completion Date, which
shall be the date on which the above  described  facilities  are  completed  and
ready for operation as designated by Kinder.

b. The  parties  agree that the  Recoupment  Fee is  designed  to allow Buyer to
recover the costs of construction  of the above described  facilities (as billed
to Kinder by Crosstex or Transco and as directly incurred by Kinder) and will be
calculated on a per MMBtu basis.  The  Recoupment  Fee shall equal (i) the total
construction  costs,  as  incurred  by  Kinder  directly  or billed to Kinder by
Crosstex  or Transco,  to  construct  or have  constructed  the above  described
facilities including, without limitation, a reasonable rate of return for Kinder
(not to  exceed  18%) and  income  tax  allowances  on  contributions  in aid of
construction that may be assessed by Kinder,  Transco, or Crosstex, as specified
by Kinder in a written  statement  to be  provided  by  Kinder,  divided by (ii)
109,500,000  MMBtu's.  Seller and Buyer  acknowledge  that the Recoupment Fee is
currently  estimated to be  approximately  $0.015 per MMBtu, but that the actual
amount will be based on the construction costs as incurred by Kinder which shall
be binding on Seller and Buyer. An estimated  Recoupment Fee of $0.015 per MMBtu
shall be used in  calculating  the Contract  Price until such time as the actual
Recoupment Fee is calculated by Kinder and provided to Buyer,  with  appropriate
retroactive  adjustments being made after the actual Recoupment Fee is known. As
a point of  information  only,  at the time of execution of this  Agreement  the
total construction  costs are estimated to be approximately  equal to the sum of
(i)  $877,000 of Transco  costs (which  includes  income tax  allowances),  (ii)
$485,000 of  Crosstex  costs (such  estimate  does not yet include an  estimated
amount for any income tax allowances that may be charged by Crosstex), and (iii)
a  reasonable  rate of return to be  charged  by Kinder  (not to exceed  18%) as
described above. The Crosstex cost estimate in the preceding  sentence  includes
$10,000 for the acquisition for right-of-way;  however,  the right-of-way  costs
have not yet been actually determined.

c.  Payout  shall mean the time at which the total  cumulative  quantity  of gas
(Seller's and third parties' gas) that flows into Crosstex'  pipeline  system at
the Delivery  Point for the Base BVN Gas (which is the  Delivery  Point noted on
Exhibit A as the "Markham PLT-Crosstex Delivery Point"), during the Limited Term
beginning with the Start Date, equals 109,500,000 MMBtu's. In order to determine
Payout,  the  number of MMBtu's on which  Seller  actually  pays Buyer an Annual
Adjustment described in Section 5 below (i.e., the quantity determined in clause
(ii) of the first  sentence of Section 5) shall be included in the  calculation.
Therefore, Payout could occur prior to the end of the Limited Term.

5. If Seller fails to deliver at least  36,500,000  MMBtu's of gas during any of
the three one year periods within the Limited Term,  then,  within sixty days of
the end of such one year  period,  Seller shall pay Buyer an amount (the "Annual
Adjustment")  equal to the product of (i) the  Recoupment  Fee per MMBtu,  times
(ii) the positive difference between (a) 36,500,000 MMBtu's,  and (b) the sum of
the amount of the Base BVN Gas that  Seller  delivered  plus all third party gas
delivered at the Markum PLT-Crosstex Delivery Point during such one year period.
No payment will be due under this Section after Payout occurs.  Seller and Buyer
acknowledge  and understand  that Transco will not commit to delivering the Base
BVN Gas at the Markam  PLTCrosstex  Delivery  Point and that, as a  consequence,
deliveries of all or a portion of Base BVN Gas may be  curtailed,  in which case
(i) the Annual Adjustments  payable under the above provisions of this Section 5
by Seller shall continue to be due and payable, and (ii) the portion of the Base
BVN Gas that cannot be delivered at the Markham PLT-Crosstex  Delivery Point due
to pressure  problems will be delivered and sold to Buyer at the other  Delivery
Point(s) for BVN Gas and at the Swing Prices specified for the Swing Quantity of
the other BVN Gas deliverable at such other Delivery  Point(s) on the applicable
day.

6.  Notwithstanding  the above provisions of this Letter  Agreement,  during any
Month in which  deliveries  of the  Base  BVN Gas are  interrupted  due to (i) a
hurricane or threat thereof,  (ii) a scheduled pipeline  maintenance of Transco,
Crosstex,  or Kinder on the systems that receive and transport the Base BVN Gas,
or (iii) a scheduled maintenance of Seller's BVN Gas production facilities,  the
Baseload  Quantity of the Base BVN Gas shall be increased (but not to exceed the
total of 100,000  MMBtu's on a Day) on the remaining Days of the Month after the
interruption  (equally over all such remaining  days),  and if necessary for the
Days of the Month prior to the interruption  (equally over all such prior days),
as may be necessary so that during the Month Seller  delivered and sold to Buyer
a daily average  Baseload  Quantity of Base BVN Gas equal to 75,000  MMBtu's per
Day  (determined  by  dividing  the  total  quantity  of Base BVN Gas  (plus any
substitute Gas described in Section 7) delivered  during the Month by the number
of Days in the  Month).  The portion of the Base BVN Gas that is Swing Gas shall
be  correspondingly  reduced on such Days during the Month on which the Baseload
Quantities of the Base BVN Gas are increased.  Nothing herein shall cause Seller
to be obligated  to sell or Buyer to be obligated to purchase  more than 100,000
MMBtu's of Base BVN Gas on any Day during the Limited Term.

7. The  parties  acknowledge  that  the  provisions  of  Section  4.2(a)  of the
Agreement  shall  apply to the Base BVN Gas if  deliveries  of Base BVN Gas fall
below  75,000  MMBtu's of gas on any Day during the Limited  Term for any reason
separate  and  distinct  from any  other  gas  Seller  has  available  under the
Agreement;  provided,  however,  the second sentence of Section 4.2(a) shall not
apply to the Base BVN Gas.  Notwithstanding anything herein to the contrary, the
first  100,000  MMBtu's of Seller's BVN Gas produced each day shall be deemed to
be Base BVN Gas. In the event that the average daily  deliveries of Base BVN Gas
hereunder falls below 75,000 MMBtu's of Gas during any Month of the Limited Term
due to production declines or a sustained production curtailment, Seller has the
right to substitute,  for delivery at the Markham  PLT-Crosstex  Delivery Point,
volumes  produced  by Seller from other  areas on the  Central  Texas  Gathering
System for any Base BVN Gas  deficiency  (daily  amount below 75,000  MMBtu's of
Gas),  beginning  with  the  second  or any  subsequent  Month  of such  reduced
deliveries.  Seller will advise Buyer that it is making the  substitution at the
same time that the Seller's Estimate is due to Buyer. All of the substituted Gas
shall be (i)  deemed  to be Base BVN Gas for all  purposes  hereunder,  and (ii)
priced at the Contract Price specified herein for the Base BVN Gas.

8. Notwithstanding  anything in the Agreement to the contrary, in the event that
Seller  terminates  the Agreement  pursuant to the second  sentence of the first
paragraph  of Section 9.1 or the last  paragraph of Section 9.1 prior to the end
of the Limited Teen, then Seller shall continue to sell and Buyer shall continue
to buy the Base BVN Gas for the remainder of the Limited Term upon the terms and
conditions  of the  Agreement  as amended by this Letter  Agreement as it may be
subsequently  amended,  and the parties shall enter into new  agreement  setting
forth such terms and conditions.

9. After the Limited Term,  all volumes of the Base BVN Gas shall continue to be
dedicated  to the  Agreement  and will be  treated  like all other gas under the
Agreement  in that,  among  other  things,  (i) there will be no minimum  volume
commitment of BVN Gas at the Markham PLTCrosstex Delivery Point, (ii) unless the
parties then mutually  agree  otherwise,  the Contract  Price for any of the gas
that had been designated as Base BVN Gas shall be either (a) if delivered at the
Markham  PLT-Crosstex  Delivery Point,  the same as the Contract Price specified
during the Limited  Term for such gas but as if Payout had  occurred,  or (b) if
delivered at any other  Delivery  Point(s) for other BVN Gas, the same  Contract
Price as  specified  for the other BVN Gas  deliverable  at such other  Delivery
Point(s),  and (iii)  Seller  will  resume  designating  a  Baseload  Designated
Percentage and a Swing Designated  Percentage for the gas formerly designated as
Base BVN Gas.

10. All provisions of the Agreement not otherwise amended herein shall remain in
full force and effect.

     If the foregoing is in accordance with your understanding of our agreement,
please  execute all copies of this letter  agreement in the space provided below
and return same to undersigned.

                                   Sincerely,

                                             CINERGY MARKETING & TRADING, LP

                                             By: /s/ Bruce A. Sukaly
                                                 -------------------
                                             Name:  Bruce A. Sukaly
                                             Title: Sr. Vice President
                                                    Natural Gas Trading &
                                                    Origination

                                           Accepted and agreed to on this 28 day
                                           of May, 2003.


KERR-MCGEE OIL & GAS CORPORATION

By: /s/ Charles D. Johnson
    ----------------------
Name: Charles D. Johnson
Its: Vice President


KERR-MCGEE OIL & GAS ONSHORE LP
BY: KERR-MCGEE OIL & GAS ONSHORE LLC,
ITS MANAGING GENERAL PARTNER

By: /s/Charles D. Johnson
    ---------------------
Name: Charles D. Johnson
Its: Senior Manager Gas Marketing