Exhibit 10.3 Centrica letter agreement


    
      

    


    Exhibit
      10.3

     

    


     

    
      	 	 	 	 	
                          Kerr-McGee
                North Sea (U.K.) Limited

                          Ninian
                House

                          Crawpell
                Road

                          Altens

                          Aberdeen
                AB12
                3LG.

            


    

    


    


    


    30th
      August 2005

    


    Centrica
      Resources Limited

    Millstream
      East

    Maidenhead
      Road

    Windsor

    Berkshire
      SL4 5GD.

    


    


    Dear
      Sirs 

     

    We
      refer to the sale and purchase agreement executed on 6th
      August 2005 between Kerr-McGee North Sea (U.K.) Limited (“Kerr-McGee”) and
      Centrica Resources Limited (“Centrica”) in respect of Kerr-McGee’s interests in
      the Buckland Field (the “Buckland SPA”) and the sale and purchase agreement
      executed on 6th
      August 2005 between Kerr-McGee North Sea (U.K.) Limited and Centrica Resources
      Limited in respect of Kerr-McGee’s interests in the Skene Field (the “Skene
      SPA”).

     

    In
      order to more clearly reflect the intention of the parties we agree
      that

     

    (1)
      with effect from 6th
      August 2005 the text of Schedule 7 to the Buckland SPA shall be deleted and
      replaced with the following text:

     

    Buckland
      Field

     

    The
      following interests held by Kerr-McGee North Sea (U.K.) Limited:

     

    Kerr-McGee’s
      thirty three decimal three three three three three three three percent
      (33.3333333%) interest in UKCS Licence P.103 Area G and Area W, as Areas G
      and W
      are defined in the Restated Northern Waters Joint Operating Agreement dated
      9th
      November 1995 as amended.

     

    (2)
      with effect from 6th
      August 2005 the text of Schedule 7 to the Skene SPA shall be deleted and
      replaced with the following text:

     

    Skene
      Field

     

    The
      following interest held by Kerr-McGee North Sea (U.K.) Limited:

     

    
      
         

      

      
         

        
          

        

      

      
         

      

    

    Kerr-McGee’s
      thirty three decimal three three three three three three three percent
      (33.3333333%) interest in UKCS Licence P.103 Area O, as Area O is defined in
      the
      Restated Northern Waters Joint Operating Agreement dated 9th November 1995
      as
      amended.

     

    (3)
      in respect of the Buckland SPA, the Base Consideration as therein defined shall
      be allocated by Centrica between Areas G and W and a notice, supplemental to
      that served on the Area G parties and the Area W parties on 10th
      August 2005, shall be served by Kerr-McGee on the Area G parties and the Area
      W
      parties stating such allocated consideration.

     

    Please
      sign and return the enclosed copy of this letter indicating your agreement
      to
      it.

     

    Yours
      faithfully

     

    TERENCE
      JUPP

     

    


     

    Kerr
      McGee North Sea (UK) Limited

     

    ANTHONY
      C. HENSHAW

     

    


     

    Agreed
      for Centrica Resources Limited