As filed with the Securities and Exchange Commission on August 10, 2006
                                                     Registration No. 333-_____
--------------------------------------------------------------------------------

                       SECURITIES AND EXCHANGE COMMISSION
                             Washington, D.C. 20549
                                -----------------
                                    FORM S-8
                             REGISTRATION STATEMENT
                                      UNDER
                           THE SECURITIES ACT OF 1933
                                -----------------

                        PIONEER NATURAL RESOURCES COMPANY
             (Exact Name of Registrant as Specified in Its Charter)

             Delaware                                       75-2702753
  (State or Other Jurisdiction of                        (I.R.S. Employer
  Incorporation or Organization)                       Identification No.)

                          5205 North O'Connor Boulevard
                                    Suite 200
                               Irving, Texas 75039
          (Address of Principal Executive Offices, Including Zip Code)
                              --------------------
     PIONEER NATURAL RESOURCES COMPANY EXECUTIVE DEFERRED COMPENSATION PLAN
                            (Full Title of the Plan)

                                  Mark S. Berg
                        Pioneer Natural Resources Company
                          5205 North O'Connor Boulevard
                                    Suite 200
                               Irving, Texas 75039
                                 (972) 444-9001

            (Name, Address and Telephone Number of Agent For Service)
                                    copy to:
                                Robert L. Kimball
                             Vinson & Elkins L.L.P.
                          2001 Ross Avenue, Suite 3700
                            Dallas, Texas 75201-2975
                                 (214) 220-7700



                         CALCULATION OF REGISTRATION FEE
=========================================================================================================
                                                 Proposed             Proposed
  Title of securities       Amount to be     maximum offering     maximum aggregate       Amount of
   to be registered          registered            price          offering price (1)   registration fee
------------------------- ---------------- -------------------- --------------------- -------------------

                                                                          
Deferred Compensation
Obligations (2) ........         (3)                 (4)            $25,000,000.00        $2,675.00
------------------------- ---------------- -------------------- --------------------- -------------------


(1)  Estimated  solely for  purposes  of  calculating  the  registration  fee in
     accordance with Rule 457(o) under the Securities Act of 1933.

(2)  The Deferred Compensation  Obligations are unsecured obligations of Pioneer
     Natural  Resources  Company to pay deferred  compensation  in the future in
     accordance  with  the  terms  of  the  Pioneer  Natural  Resources  Company
     Executive Deferred Compensation Plan.

(3)  Pursuant  to Rule  416(c)  under  the  Securities  Act,  this  Registration
     Statement also registers an indeterminate amount of plan interests.

(4)  Pursuant to Rule  457(h)(2)  under the  Securities  Act, no separate fee is
     required to register plan interests.









                                     PART I
              INFORMATION REQUIRED IN THE SECTION 10(a) PROSPECTUS

     Pioneer Natural Resources Company (the "Registrant" or "Company") will send
or give to all participants in the Pioneer Natural  Resources  Company Executive
Deferred  Compensation Plan the document(s)  containing  information required by
Part I of Form S-8, as specified in Rule 428(b)(1) promulgated by the Securities
and Exchange  Commission (the "Commission") under the Securities Act of 1933, as
amended (the  "Securities  Act").  The Registrant has not filed such document(s)
with the Commission,  but such documents (along with the documents  incorporated
by  reference  into  this Form S-8  Registration  Statement  (the  "Registration
Statement")  pursuant to Item 3 of Part II hereof) shall constitute a prospectus
that meets the requirements of Section 10(a) of the Securities Act.

                                     PART II
               INFORMATION REQUIRED IN THE REGISTRATION STATEMENT

     This  Registration  Statement is being filed,  in  accordance  with General
Instruction  E  to  Form  S-8,  to  register  additional  deferred  compensation
obligations of the Company that may become payable under the Company's Executive
Deferred  Compensation  Plan (as  amended,  the  "Plan").  The  contents  of the
Company's  registration  statement  on Form S-8 filed on October  31, 1997 (File
Number  333-39153),  relating to the Plan, are hereby  incorporated by reference
into this Registration Statement.

Item 3.  Incorporation of Documents by Reference.

     Except to the extent that  information  is deemed  furnished  and not filed
pursuant to securities laws and regulations,  the following  documents have been
filed by the Company with the Commission and are  incorporated by reference into
this Registration Statement and will be deemed to be a part hereof:

     (a) The Registrant's Annual Report on Form 10-K (File No. 001-13245), filed
with the Commission on February 17, 2006, for the fiscal year ended December 31,
2005.

     (b) The Registrant's  Quarterly Reports on Form 10-Q (File No.  001-13245),
filed with the  Commission on May 10, 2006,  for the fiscal  quarter ended March
31, 2006, and on August 8, 2006, for the fiscal quarter ended June 30, 2006.

     (c) The  Registrant's  Current  Reports  on Form 8-K (File No.  001-13245),
filed with the Commission on May 25, 2006 (Item 7.01); May 23, 2006 (Items 1.01,
3.03, and 9.01);  May 9, 2006 (Items 1.01 and 9.01); May 4, 2006 (Items 1.01 and
9.01);  May 1, 2006 (Items 1.01 and 9.01);  April 3, 2006 (Items 2.01 and 9.01);
February  28, 2006 (Items 1.01 and 9.01);  February  21, 2006 (Item  1.01);  and
January 20, 2006 (Items 8.01 and 9.01).

     (d) All other reports filed by the  Registrant  with the  Commission  since
December 31, 2005 pursuant to Section 13(a) or 15(d) of the Securities  Exchange
Act of 1934, as amended (the "Exchange Act").

     Except to the extent that  information  is deemed  furnished  and not filed
pursuant to securities laws and regulations, all documents subsequently filed by
the Registrant  pursuant to Sections 13(a),  13(c), 14 and 15(d) of the Exchange
Act prior to the filing of a  post-effective  amendment  that indicates that all
securities  offered  have  been sold or that  deregisters  all  securities  then
remaining unsold shall also be deemed to be incorporated by reference herein and
to be a part hereof from the dates of filing of such  documents.  Any  statement
contained in a document  incorporated  or deemed to be incorporated by reference
herein  shall be  deemed to be  modified  or  superseded  for  purposes  of this
Registration Statement to the extent that a statement contained herein or in any
other  subsequently filed document which also is or is deemed to be incorporated
by reference  herein  modifies or supersedes  such  statement.  Any statement so
modified or superseded shall not be deemed, except as so modified or superseded,
to constitute a part of this Registration Statement.

Item 4.  Description of Securities.

     The securities to be offered under this  Registration  Statement  represent
unsecured  obligations of the Registrant to pay to the  participants in the Plan
certain  salary,  bonus,  and  other  compensation,  the  receipt  of which  the
participants  have elected to defer under the Plan (the  "Deferred  Compensation


                                      II-1





Obligations"). The Deferred Compensation Obligations also represent amounts that
the  Registrant   credits  to  participants'   accounts  as  employer   matching
contributions.  Each participant shall designate the manner in which the amounts
allocated to his account will be deemed to be invested from among the investment
funds  and  other   securities   designated  from  time  to  time  by  the  Plan
administrator.  Amounts  credited to a  participant's  account are  adjusted for
earnings  and/or  losses each  business  day. If no  investment  option has been
selected,  a  participant's  accounts  will  be  deemed  to be  invested  in the
investments  designated  by the Plan  Administrator.  The Deferred  Compensation
Obligations are payable in cash in a lump-sum  distribution or in  installments,
at the election of the participant made in accordance with the Plan. There is no
trading market for the Deferred Compensation Obligations.

     The Deferred Compensation  Obligations are unsecured general obligations of
the  Registrant  and rank pari  passu with other  unsecured  and  unsubordinated
indebtedness of the Registrant.  The Deferred  Compensation  Obligations are not
subject in any manner to anticipation,  alienation, sale, transfer,  assignment,
pledge or encumbrance.  Any attempt by any person to transfer or assign benefits
under the Plan,  other than a claim for  benefits by a  participant,  his or her
beneficiary,  or an alternate payee under a qualified  domestic relations order,
will be null and void. The Deferred Compensation Obligations are not convertible
into any other security of the Registrant.

     The Registrant has  established a Trust to hold all income,  contributions,
and moneys of any kind at any time received by the Trustee and such amounts will
be held for investment purposes as a commingled Trust Fund pursuant to the terms
of the Trust Agreement.  Participants in the Plan have no rights to any specific
assets held in the Trust except as general  creditors of the Registrant.  Assets
in any  trust  or  fund  will at all  times  be  subject  to the  claims  of the
Registrant's general creditors.

     A  participant  may request an early  payment of the Deferred  Compensation
Obligations  for the  purpose  of  alleviating  an  immediate  and  unforseeable
financial emergency, as determined pursuant to the Plan.

     The  Registrant  reserves  the right to amend the Plan at any time,  except
that  no  amendment,   modification  or  termination  will  adversely  affect  a
participant's  rights in his or her Plan account.  The  Registrant may terminate
the  Plan  at  an  time  and,  upon  termination,  the  amounts  credited  to  a
participant's  account  will  be  paid  in the  manner  specified  by  the  Plan
administrator.

     The description above of the Deferred Compensation Obligations is qualified
in its entirety by  reference  to the full text of the Plan, a complete  copy of
which is filed as Exhibit 4.1 to this Registration Statement.

Item 5.  Interests of Named Experts and Counsel.

     Not applicable.

Item 6.  Indemnification of Directors and Officers.

Delaware General Corporation Law

     Section  145  of the  Delaware  General  Corporation  Law  provides  that a
corporation  may  indemnify any person who was or is a party or is threatened to
be  made a  party  to any  threatened,  pending  or  completed  action,  suit or
proceeding, whether civil, criminal, administrative or investigative (other than
an action by or in the right of the  corporation) by reason of the fact that the
person is or was a director,  officer, employee or agent of the corporation,  or
is or was serving at the  request of the  corporation  as a  director,  officer,
employee or agent of another corporation,  partnership,  joint venture, trust or
other enterprise against expenses (including attorneys' fees), judgments,  fines
and amounts paid in settlement actually and reasonably incurred by the person in
connection  with such  action,  suit or  proceeding  if the person acted in good
faith and in a manner the person reasonably  believed to be in or not opposed to
the best interests of the corporation,  and, with respect to any criminal action
or  proceeding,  had no  reasonable  cause to believe the  person's  conduct was
unlawful.  In  actions  brought  by or in  the  right  of the  corporation,  the
corporation  may indemnify such person against  expenses  (including  attorneys'
fees)  actually and  reasonably  incurred by the person in  connection  with the
defense or  settlement  of the action or suit if the person  acted in good faith
and in a manner the person  reasonably  believed  to be in or not opposed to the
best interests of the  corporation and except that no  indemnification  shall be
made in respect of any claim,  issue or matter as to which the person shall have
been adjudged to be liable to the corporation unless and only to the extent that
the  Delaware  Court of  Chancery  or the court in which the  action or suit was
brought shall  determine upon  application  that,  despite the  adjudication  of

                                      II-2






liability but in view of all the circumstances of the case, the person is fairly
and  reasonably  entitled to indemnity for the expenses which the Delaware Court
of Chancery or such other court shall deem proper.

     To the  extent  that  such  person  has been  successful  on the  merits or
otherwise in defending any action,  suit or proceeding  referred to above, or in
defense  of any such  claim,  issue  or  matter  therein,  the  person  shall be
indemnified against expenses (including attorneys' fees) actually and reasonably
incurred by such person in connection therewith.

     The  indemnification  and  advancement  of expenses  provided by or granted
pursuant  to Section  145 is not  exclusive  of any other  rights to which those
seeking  indemnification  or  advancement  of expenses  may be  entitled,  and a
corporation  may purchase and maintain  insurance on behalf of any person who is
or was a director,  officer, employee or agent of the corporation,  or is or was
serving at the request of the  corporation as a director,  officer,  employee or
agent  of  another  corporation,  partnership,  joint  venture,  trust  or other
enterprise against any liability asserted against the person and incurred by the
person in any such  capacity,  or arising  out of the  person's  status as such,
whether or not the power to indemnify is provided by the statute.

     The preceding discussion of Section 145 of the Delaware General Corporation
Law is not  intended  to be  exhaustive  and is  qualified  in its  entirety  by
reference to Section 145 of the Delaware General Corporation Law.

Amended and Restated Certificate of Incorporation

     Article  Twelfth of the  Company's  Amended  and  Restated  Certificate  of
Incorporation  provides that each person who at any time is or was a director or
officer of the  Company,  or any person who,  while a director or officer of the
Company,  is or was serving at the  Company's  request as a  director,  officer,
partner, venturer,  proprietor,  trustee, employee, agent or similar functionary
of  another  foreign  or  domestic   corporation,   limited  liability  company,
association,  partnership,  joint venture, sole proprietorship,  trust, employee
benefit plan or other enterprise,  shall be entitled to (a)  indemnification and
(b) the advancement of expenses incurred by such person from the Company as, and
to the fullest extent,  permitted by the Delaware General Corporation Law or any
successor  statutory  provision,  as from time to time  amended.  Any  repeal or
modification  of  Article   Twelfth  of  the  Company's   Amended  and  Restated
Certificate of Incorporation  shall be prospective only, and shall not adversely
affect the rights of any director or officer or the  obligations  of the Company
with respect to any claim  arising from the services of such director or officer
in the  capacities  described  above  prior to any such repeal or  amendment  of
Article Twelfth.

     Article  Thirteenth of the Company's  Amended and Restated  Certificate  of
Incorporation  provides  that the  Company's  directors  shall not be personally
liable to the Company or any of its stockholders for monetary damages for breach
of  fiduciary  duty as a  director  involving  any act or  omission  of any such
director;  provided, however, that such Article Thirteenth does not eliminate or
limit the liability of a director (1) for any breach of such  director's duty of
loyalty to the Company or its  stockholders,  (2) for acts or  omissions  not in
good faith or which involve  intentional  misconduct  or a knowing  violation of
law,  (3) under  Section  174 of the  Delaware  General  Corporation  Law (which
relates  to  certain   unlawful   dividend   payments  or  stock   purchases  or
redemptions),  as the same exists or may hereafter be amended,  supplemented  or
replaced,  or (4) for a transaction  from which the director derived an improper
personal  benefit.  If  the  Delaware  General  Corporation  Law is  amended  to
authorize the further  elimination  or limitation of the liability of directors,
then the  liability  of a director,  in addition to the  limitation  on personal
liability  described above,  shall be limited to the fullest extent permitted by
the Delaware General Corporation Law, as so amended.  Furthermore, any repeal or
modification  of  Article  Thirteenth  of the  Company's  Amended  and  Restated
Certificate of Incorporation by its stockholders  shall be prospective only, and
shall not  adversely  affect  any  limitation  on the  personal  liability  of a
director existing at the time of such repeal or modification.

Indemnification Agreements

     The Company has entered into indemnification  agreements with its directors
and officers. Under the terms of the indemnification agreements, the Company has
generally agreed to indemnify an officer or director for liabilities incurred to
the fullest  extent  permitted  by the  Delaware  General  Corporation  Law. The
Company must, within ten days of a request, indemnify an officer or director for
expenses incurred in the defense of a claim or other proceeding.  The obligation

                                      II-3






of the Company to provide the indemnification does not apply if, before the date
on which the Company must provide the  indemnification,  the Company's  board of
directors, or a representative chosen by the board of directors,  concludes that
indemnification would be improper under the Delaware General Corporation Law.

     The above  discussion  of Section 145 of the Delaware  General  Corporation
Law, the Company's  amended and restated  certificate of  incorporation  and the
indemnification  agreements is not intended to be exhaustive and is respectively
qualified in its entirety by such statute and documents.

Item 7.  Exemption from Registration Claimed.

     Not applicable.

Item 8.  Exhibits.

     Unless  otherwise  indicated  below as being  incorporated  by reference to
another  filing  of the  Company  with  the  Commission,  each of the  following
exhibits is filed herewith:

     3.1       Amended and Restated  Certificate of Incorporation of the Company
               (incorporated  by  reference  to Exhibit  3.1  to  the  Company's
               Registration Statement on Form S-4 (No. 333-26951) filed with the
               Commission on June 26, 1997).

     3.2       Amended and  Restated  Bylaws of  the  Company  (incorporated  by
               reference  to Exhibit 3.2 to the  Company's Annual Report on Form
               10-K (No. 001-13245)  filed with the  Commission on  February 17,
               2006).

     4.1       Pioneer Natural Resources Company Executive Deferred Compensation
               Plan,  as  amended   and  restated   effective  August  1,   2002
               (incorporated  by reference to Exhibit 10.15 to the  Registrant's
               Quarterly  Report on  Form 10-Q (No.  001-13245)  filed  with the
               Commission on May 6, 2005).

     5.1       Opinion of Vinson & Elkins L.L.P.

     23.1      Consent of Ernst & Young LLP.

     23.2      Consent of Netherland, Sewell & Associates, Inc.

     23.3      Consent of Vinson & Elkins L.L.P. (included in the  opinion filed
               as Exhibit 5.1 to this registration statement).

     24.1      Power of  Attorney  (included  on  the  signature  pages  of this
               registration statement).

Item 9.  Undertakings.

     (a) The undersigned Registrant hereby undertakes:

         1. To file,  during any period in which offers or sales are being made,
     a post-effective amendment to this Registration Statement:

            (i) To include  any prospectus  required by  Section 10(a)(3) of the
          Securities Act;

            (ii) To reflect in the  prospectus any facts or events arising after
          the effective  date of the  Registration Statement (or the most recent
          post-effective  amendment  thereof)  which,  individually  or  in  the
          aggregate, represent a fundamental change in the information set forth
          in the Registration Statement; and

                                      II-4






            (iii) To include any material  information with  respect to the plan
          of distribution not previously disclosed in the Registration Statement
          or any  material  change  to  such  information  in  the  Registration
          Statement;

     provided, however, that paragraphs (a)(1)(i) and (a)(1)(ii) do not apply if
     the information  required to be  included in a  post-effective amendment by
     those paragraphs is contained in periodic  reports filed by the  Registrant
     pursuant to  Section  13 or  Section  15(d)  of the  Exchange Act  that are
     incorporated by reference in the Registration Statement.

         2. That,  for  the  purpose of  determining  any  liability  under  the
     Securities Act, each such  post-effective amendment shall be deemed to be a
     new registration statement relating  to the securities offered therein, and
     the offering  of such  securities  at that time  shall be  deemed to be the
     initial bona fide offering thereof.

         3. To remove from  registration  by means of a post-effective amendment
     any  of  the  securities  being  registered  which  remain  unsold  at  the
     termination of the offering.

     (b) The  undersigned  Registrant  hereby  undertakes  that, for purposes of
determining  any  liability  under  the  Securities  Act,  each  filing  of  the
Registrant's  annual  report  pursuant to Section  13(a) or Section 15(d) of the
Exchange Act (and, where  applicable,  each filing of an employee benefit plan's
annual  report   pursuant  to  Section  15(d)  of  the  Exchange  Act)  that  is
incorporated by reference in the Registration  Statement shall be deemed to be a
new registration  statement relating to the securities offered therein,  and the
offering of such  securities at that time shall be deemed to be the initial bona
fide offering thereof.

     (c) Insofar as indemnification for liabilities arising under the Securities
Act may be  permitted to  directors,  officers  and  controlling  persons of the
Registrant pursuant to the foregoing  provisions,  or otherwise,  the Registrant
has been advised that in the opinion of the Commission such  indemnification  is
against  public  policy as expressed in the  Securities  Act and is,  therefore,
unenforceable.  In the  event  that a claim  for  indemnification  against  such
liabilities  (other than the payment by the  Registrant of expenses  incurred or
paid by a  director,  officer or  controlling  person of the  Registrant  in the
successful  defense of any  action,  suit or  proceeding)  is  asserted  by such
director,  officer or controlling person in connection with the securities being
registered, the Registrant will, unless in the opinion of its counsel the matter
has been  settled by  controlling  precedent,  submit to a court of  appropriate
jurisdiction  the question  whether such  indemnification  by the  Registrant is
against  public  policy as  expressed  in the  Securities  Act and  agrees to be
governed by the final adjudication of such issue.


                                      II-5






                                   SIGNATURES

     Pursuant  to  the  requirements  of  the  Securities  Act,  the  Registrant
certifies  that it has  reasonable  grounds to believe  that it meets all of the
requirements  for  filing  on Form S-8 and has  duly  caused  this  Registration
Statement  to be  signed  on its  behalf  by  the  undersigned,  thereunto  duly
authorized, in the City of Irving, State of Texas, on August 10, 2006.

                                          PIONEER NATURAL RESOURCES COMPANY


                                          By: /s/ Scott D. Sheffield
                                              ---------------------------------
                                                   Scott D. Sheffield
                                                   Chairman of the Board and
                                                   Chief Executive Officer

     KNOW ALL MEN BY THESE PRESENTS,  that each person whose  signature  appears
below  constitutes  and appoints Mark S. Berg and Richard P. Dealy,  and each of
them,  his true and  lawful  attorneys-in-fact  and  agents,  with full power of
substitution  and  resubstitution,  for him and in his name, place and stead, in
any and all  capacities,  to sign  any  and all  amendments  (including  pre-and
post-effective  amendments)  to this  Registration  Statement and any additional
registration  statement pursuant to Rule 462(b) under the Securities Act, and to
file the same with all  exhibits  thereto,  and other  documents  in  connection
therewith, with the Commission, granting unto said attorneys-in-fact and agents,
and each of them,  full power and authority to do and perform each and every act
and thing  requisite  and  necessary  to be done,  as fully to all  intents  and
purposes as he might or could do in person,  hereby ratifying and confirming all
that  said  attorneys-in-fact  and  agents,  or any  of  them,  or his or  their
substitute or substitutes may lawfully do or cause to be done by virtue hereof.

     Pursuant to the  requirements  of the  Securities  Act,  this  Registration
Statement has been signed by the following  persons in the capacities and on the
date indicated.

              Signature                     Title                     Date
              ---------                     -----                     ----

/s/ Scott D. Sheffield
---------------------------
    Scott D. Sheffield            Chairman of the Board and      August 10, 2006
                                   Chief Executive Officer
                                (Principal Executive Officer)

/s/ Richard P. Dealy
---------------------------
    Richard P. Dealy             Executive Vice President and    August 10, 2006
                                   Chief Financial Officer
                                (Principal Financial Officer)

/s/ Darin G. Holderness
---------------------------
    Darin G. Holderness               Vice President and         August 10, 2006
                                   Chief Accounting Officer
                                (Principal Accounting Officer)

/s/ James R. Baroffio
---------------------------
    James R. Baroffio                      Director              August 10, 2006

/s/ Edison C. Buchanan
---------------------------
    Edison C. Buchanan                     Director              August 9, 2006


                                      II-6





/s/ R. Hartwell Gardner
---------------------------
    R. Hartwell Gardner                    Director              August 10, 2006

/s/ Linda K. Lawson
---------------------------
    Linda K. Lawson                        Director              August 10, 2006

/s/ Andrew D. Lundquist
---------------------------
    Andrew D. Lundquist                    Director              August 3, 2006

/s/ Charles E. Ramsey, Jr.
---------------------------
    Charles E. Ramsey, Jr.                 Director              August 10, 2006

/s/ Frank A. Risch
---------------------------
    Frank A. Risch                         Director              August 10, 2006

/s/ Mark S. Sexton
---------------------------
    Mark S. Sexton                         Director              August 10, 2006

/s/ Robert A. Solberg
---------------------------
    Robert A. Solberg                      Director              August 8, 2006

/s/ Jim A. Watson
---------------------------
    Jim A. Watson                          Director              August 2, 2006



     Pursuant to the  requirements of the Securities Act, the trustees (or other
persons  who  administer  the  employee  benefit  plan)  have duly  caused  this
registration statement to be signed on its behalf by the undersigned,  thereunto
duly authorized, in the City of Irving, State of Texas, on August 9, 2006.

                                     PIONEER NATURAL RESOURCES COMPANY
                                     EXECUTIVE DEFERRED COMPENSATION PLAN

                                     By: Compensation and Management Development
                                     Committee of the Board of Directors of
                                     Pioneer Natural Resources Company


                                        By: /s/ Edison C. Buchanan
                                            -----------------------------
                                            Edison C. Buchanan, Chairman

                                      II-7








                                INDEX TO EXHIBITS

Exhibit
Number        Description
-------       -----------

  3.1         Amended and  Restated  Certificate of Incorporation of the Company
              (incorporated  by  reference  to  Exhibit  3.1  to  the  Company's
              Registration  Statement on Form S-4 (No. 333-26951) filed with the
              Commission on June 26, 1997).

  3.2         Amended  and  Restated  Bylaws  of  the Company  (incorporated  by
              reference  to Exhibit 3.2 to the  Company's  Annual Report on Form
              10-K  (No. 001-13245) filed  with the  Commission on  February 17,
              2006).

  4.1         Pioneer Natural Resources Company Executive Deferred  Compensation
              Plan,  as   amended  and   restated  effective   August  1,   2002
              (incorporated  by  reference to Exhibit 10.15 to the  Registrant's
              Quarterly  Report  on  Form 10-Q  (No.  001-13245) filed  with the
              Commission on May 6, 2005).

  5.1         Opinion of Vinson & Elkins L.L.P.*

  23.1        Consent of Ernst & Young LLP.*

  23.2        Consent of Netherland, Sewell & Associates, Inc.*

  23.3        Consent of  Vinson & Elkins  L.L.P. (included in the opinion filed
              as Exhibit 5.1 to this registration statement).*

  24.1        Power  of Attorney  (included  on  the  signature  pages  of  this
              registration statement).*


 *filed herewith.