<PAGE>
                           PURCHASE AND SALE AGREEMENT
                                 BY AND BETWEEN
                         COLORADO INTERSTATE GAS COMPANY
                           EL PASO PRODUCTION GOM INC.
                                       AND
                          CIG PRODUCTION COMPANY, L.P.
                                    AS SELLER

                                       AND

                       PIONEER NATURAL RESOURCES USA, INC.
                                    AS BUYER


                                PROPERTY PACKAGE
                              PANHANDLE AREA, TEXAS
                              KEYES AREA, OKLAHOMA
                                 GULF OF MEXICO
                                       AND
                             GREENWOOD AREA, KANSAS




PRODUCTION ASSETS

<PAGE>
                                TABLE OF CONTENTS
<TABLE>
<CAPTION>
                                                                                                                PAGE
<S>                                                                                                              <C>
1.    SALE AND PURCHASE OF THE ASSETS  ........................................................................   1
      1.1         Acquired Assets  ............................................................................   1
      1.2         Excluded Assets  ............................................................................   3
      1.3         Assumed Liabilities  ........................................................................   3
      1.4         Retained Liabilities  .......................................................................   4
      1.5         'B' Contract Document Effect  ...............................................................   4

2.    PURCHASE PRICE  .........................................................................................   4
      2.1         Purchase Price  .............................................................................   4
      2.2         Adjustments to the Base Purchase Price  .....................................................   4
      2.3         Allocation  .................................................................................   7
      2.4         Allocation for Tax Purposes  ................................................................   7

3.    CLOSING  ................................................................................................   8
      3.1         Closing  ....................................................................................   8
      3.2         Delivery by Seller  .........................................................................   8
      3.3         Delivery by Buyer  ..........................................................................   9
      3.4         Further Cooperation  ........................................................................   9
      3.5         Notice of Breach  ...........................................................................   9

4.    ACCOUNTING ADJUSTMENTS  .................................................................................  10
      4.1         Closing Adjustments  ........................................................................  10
      4.2         Strapping and Gauging  ......................................................................  10
      4.3         [INTENTIONALLY DELETED]  ....................................................................  10
      4.4         Post-Closing Adjustments  ...................................................................  10
      4.5         Suspended Funds  ............................................................................  11
      4.6         Audit Adjustments  ..........................................................................  11
      4.7         Asset Tax Refunds  ..........................................................................  12
      4.8         Capital Expenditures  .......................................................................  12
      4.9         Cooperation  ................................................................................  12
      4.10        [INTENTIONALLY DELETED]  ....................................................................  13

5.    DUE DILIGENCE; TITLE MATTERS  ...........................................................................  13
      5.1         General Access  .............................................................................  13
      5.2         Seller's Title  .............................................................................  13
      5.3         Good and Marketable Title  ..................................................................  14
      5.4         Waived Purchase Price Adjustments  ..........................................................  17
      5.5         Defect Letters  .............................................................................  17
      5.6         Effect of Title Defect  .....................................................................  19
      5.7         Possible Upward Adjustment  .................................................................  21
      5.8         Exclusive Remedy  ...........................................................................  21
</TABLE>
<PAGE>
<TABLE>
<S>                                                                                                              <C>
6.    ENVIRONMENTAL ISSUES  ...................................................................................  21
      6.1         Resolution of Environmental Issues  .........................................................  21
      6.2         Seller's $5,000,000 Post-Closing Environmental Contribution  ................................  21
      6.3         Buyer's and Seller's 50/50 Sharing of Costs and Expenses for Certain Groundwater
                  Matters .....................................................................................  22
      6.4         Cooperation and Final Decision  .............................................................  22
      6.5         Physical Condition of the Asset  ............................................................  22
      6.6         Inspection and Testing  .....................................................................  23
      6.7         Adverse Environmental Conditions  ...........................................................  24
      6.8         Definition  .................................................................................  24
      6.9         Remediation  ................................................................................  25

7.    REPRESENTATIONS AND WARRANTIES OF SELLER  ...............................................................  25
      7.1         Seller's Representations and Warranties  ....................................................  25
      7.2         Scope of Representations of Seller  .........................................................  28

8.    REPRESENTATIONS AND WARRANTIES OF BUYER  ................................................................  29
      8.1         Buyer's Representations and Warranties  .....................................................  29

9.    CERTAIN AGREEMENTS OF SELLER  ...........................................................................  30
      9.1         Maintenance of Assets  ......................................................................  30
      9.2         Consents or Assignments  ....................................................................  31
      9.3         Preferential Rights  ........................................................................  32
      9.4         [INTENTIONALLY DELETED]  ....................................................................  32
      9.5         Records and Contracts  ......................................................................  32
      9.6         Termination of Affiliate Contracts  .........................................................  33
      9.7         Gas Quality Waiver  .........................................................................  33

10.   CERTAIN AGREEMENTS OF BUYER  ............................................................................  33
     10.1         [INTENTIONALLY DELETED]  ....................................................................  33
     10.2         Plugging Bond  ..............................................................................  33
     10.3         Seller's Logo  ..............................................................................  33
     10.4         [INTENTIONALLY DELETED]  ....................................................................  34
     10.5         Like-Kind Exchanges  ........................................................................  34
     10.6         [INTENTIONALLY DELETED]  ....................................................................  34

11.  CONDITIONS PRECEDENT TO BUYER  ...........................................................................  34
     11.1         No Litigation  ..............................................................................  34
     11.2         Representations and Warranties  .............................................................  34
     11.3         [INTENTIONALLY DELETED]  ....................................................................  34
     11.4         Acquisition of Gathering Assets  ............................................................  34
     11.5         Seller's receipt of Waiver  .................................................................  34

12.  CONDITIONS PRECEDENT TO THE OBLIGATIONS OF SELLER  .......................................................  35
</TABLE>
<PAGE>
<TABLE>
<S>                                                                                                              <C>
     12.1         No litigation  ..............................................................................  35
     12.2         Representations and Warranties  .............................................................  35
     12.3         Waivers of Restrictions  ....................................................................  35
     12.4         Disposition of Gathering Assets  ............................................................  35

13.  TERMINATION  .............................................................................................  35
     13.1         Causes of Termination  ......................................................................  35
     13.2         Effect of Termination  ......................................................................  36

14.  INDEMNIFICATION  .........................................................................................  36
     14.1         Indemnification by seller  ..................................................................  36
     14.2         Indemnification by Buyer  ...................................................................  38
     14.3         Additional Plugging Obligations  ............................................................  39
     14.4         Notification  ...............................................................................  39
     14.5         Limitations on Damages  .....................................................................  40

15.  MISCELLANEOUS  ...........................................................................................  40
     15.1         Casualty Loss  ..............................................................................  40
     15.2         Third Party Beneficiaries  ..................................................................  41
     15.3         Competition  ................................................................................  41
     15.4         Notice   ....................................................................................  41
     15.5         Press Releases and Public Announcements   ...................................................  42
     15.6         Personnel    ................................................................................  42
     15.7         Compliance With Express Negligence Test    ..................................................  42
     15.8         Governing Law    ............................................................................  43
     15.9         Exhibits    .................................................................................  43
    15.10         Fees, expenses, Taxes and Recording   .......................................................  43
    15.11         Assignment   ................................................................................  43
    15.12         Entire Agreement    .........................................................................  44
    15.13         Severability   ..............................................................................  44
    15.14         Captions   ..................................................................................  44
    15.15         Survival   ..................................................................................  44
</TABLE>


EXHIBITS:


A                 'B' Contract Documents
1.1(A)-1           Leases
1.1(A)-2           Wells
X                  Restrictions on the Purchase and Sale of Greenwood C-1,
                   Greenwood Field, Morton County Kansas
<PAGE>

1.1(A)(iii)       Easements
1.2               Excluded Assets
2.2(A)(v)         Split Interest Well Imbalances
2.3               Allocation
3.2(A)            Form of Assignment
3.2(B)            Certifications of Non-Foreign Status
3.2(H)            Transition Agreement
5.3(B)            Gas Purchase, Sales, Processing and Other Agreements
5.3(B)(ii)(6)     Liens
7.1(D)            Authorization for Expenditure's
7.1(E)            Contractual Restrictions
7.1(F)            Litigation
7.1(I)            Tax Liability
7.1(L)            Valid Agreements
15.15





<PAGE>

                             INDEX OF DEFINED TERMS

<Table>
<Caption>
----------------------------------------------------------------------------------------------------------------------
                 DEFINED TERM                                 SECTION                              PAGE
----------------------------------------------------------------------------------------------------------------------
<S>                                                          <C>                                    <C>
Administrative Fee                                              4.6                                 11
----------------------------------------------------------------------------------------------------------------------
Adverse Environmental Condition                                 6.7                                 24
----------------------------------------------------------------------------------------------------------------------
Agreement                                                    Preamble                               1
----------------------------------------------------------------------------------------------------------------------
Allocated Value/Allocated Values                                2.3                                 7
----------------------------------------------------------------------------------------------------------------------
Assets                                                          1.1                                 1
----------------------------------------------------------------------------------------------------------------------
Asset Tax                                                   2.2(A)(ii)                              5
----------------------------------------------------------------------------------------------------------------------
Assumed Liabilities                                             1.3                                 4
----------------------------------------------------------------------------------------------------------------------
Base Purchase Price                                             2.1                                 4
----------------------------------------------------------------------------------------------------------------------
'B' Contract                                                 Preamble                               1
----------------------------------------------------------------------------------------------------------------------
'B' Contract Documents                                       Preamble                               1
----------------------------------------------------------------------------------------------------------------------
Buyer                                                        Preamble                               1
----------------------------------------------------------------------------------------------------------------------
Buyer Group                                                    14.1                                 36
----------------------------------------------------------------------------------------------------------------------
Buyer's Response                                            5.5(C)(ii)                              18
----------------------------------------------------------------------------------------------------------------------
Casualty                                                      15.1(A)                               40
----------------------------------------------------------------------------------------------------------------------
Casualty Loss                                                 15.1(B)                               40
----------------------------------------------------------------------------------------------------------------------
CIG                                                          Preamble                               1
----------------------------------------------------------------------------------------------------------------------
CIGPC                                                        Preamble                               1
----------------------------------------------------------------------------------------------------------------------
Closing                                                         3.1                                 8
----------------------------------------------------------------------------------------------------------------------
Closing Adjustment Statement                                    4.1                                 7
----------------------------------------------------------------------------------------------------------------------
Closing Date                                                    3.1                                 8
----------------------------------------------------------------------------------------------------------------------
Code                                                            2.4                                 7
----------------------------------------------------------------------------------------------------------------------
Contracts                                                     1.1(C)                                2
----------------------------------------------------------------------------------------------------------------------
Effective Time                                              2.2(A)(iii)                             5
----------------------------------------------------------------------------------------------------------------------
El Paso                                                      Preamble                               1
----------------------------------------------------------------------------------------------------------------------
Environmental Laws                                            6.6(C)                                23
----------------------------------------------------------------------------------------------------------------------
ERISA                                                         15.6(B)                               42
----------------------------------------------------------------------------------------------------------------------
</TABLE>
<PAGE>
<Table>
<Caption>
----------------------------------------------------------------------------------------------------------------------
                 DEFINED TERM                                 SECTION                              PAGE
----------------------------------------------------------------------------------------------------------------------
<S>                                                         <C>                                     <C>
----------------------------------------------------------------------------------------------------------------------
Excluded Assets                                                 1.2                                 3
----------------------------------------------------------------------------------------------------------------------
Excluded Records                                                9.5                                 32
----------------------------------------------------------------------------------------------------------------------
Gathering Initial Closing                                      11.4                                 34
----------------------------------------------------------------------------------------------------------------------
Good and Marketable                                             5.3                                 14
----------------------------------------------------------------------------------------------------------------------
Imbalance                                                   2.2(B)(vi)                              7
----------------------------------------------------------------------------------------------------------------------
Interest                                                    2.2(A)(vii)                             5
----------------------------------------------------------------------------------------------------------------------
Leases                                                        1.1(A)                                2
----------------------------------------------------------------------------------------------------------------------
Loss/Losses                                                   14.1(A)                               36
----------------------------------------------------------------------------------------------------------------------
Net Revenue Interest                                         5.3(A)(i)                              14
----------------------------------------------------------------------------------------------------------------------
NORM                                                            6.5                                 23
----------------------------------------------------------------------------------------------------------------------
Notice                                                        5.5(A)                                17
----------------------------------------------------------------------------------------------------------------------
Oil and Gas                                                   1.1(B)                                2
----------------------------------------------------------------------------------------------------------------------
PAA                                                          2.2(A)(v)                              5
----------------------------------------------------------------------------------------------------------------------
Party/Parties                                                Preamble                               1
----------------------------------------------------------------------------------------------------------------------
Permitted Encumbrances                                      5.3(B)(ii)                              14
----------------------------------------------------------------------------------------------------------------------
Pioneer Operating Agreement                                     4.6                                 11
----------------------------------------------------------------------------------------------------------------------
Post-Closing Adjustment Statement                             4.4(A)                                10
----------------------------------------------------------------------------------------------------------------------
Preferential Rights                                           9.3(A)                                32
----------------------------------------------------------------------------------------------------------------------
Purchase Price                                                  2.1                                 4
----------------------------------------------------------------------------------------------------------------------
Records                                                       1.1(J)                                3
----------------------------------------------------------------------------------------------------------------------
Related Assets                                                1.1(D)                                2
----------------------------------------------------------------------------------------------------------------------
Remediate/Remediation                                           6.8                                 24
----------------------------------------------------------------------------------------------------------------------
Seller                                                       Preamble                               1
----------------------------------------------------------------------------------------------------------------------
Seller Group                                                  6.6(B)                                23
----------------------------------------------------------------------------------------------------------------------
Seller's Response                                            5.5(C)(i)                              18
----------------------------------------------------------------------------------------------------------------------
Tax/Taxes                                                     7.1(I)                                27
----------------------------------------------------------------------------------------------------------------------
Title Benefit                                                   5.7                                 21
----------------------------------------------------------------------------------------------------------------------
Title Consultant                                            5.5(C)(iii)                             18
----------------------------------------------------------------------------------------------------------------------
</TABLE>
<PAGE>
<Table>
<Caption>
----------------------------------------------------------------------------------------------------------------------
                 DEFINED TERM                                 SECTION                              PAGE
----------------------------------------------------------------------------------------------------------------------
<S>                                                         <C>                                     <C>
----------------------------------------------------------------------------------------------------------------------
Title Defect Hurdle Rate                                      5.5(A)                                17
----------------------------------------------------------------------------------------------------------------------
Title Defect Value                                            5.6(B)                                20
----------------------------------------------------------------------------------------------------------------------
Units                                                         1.1(A)                                2
----------------------------------------------------------------------------------------------------------------------
Valid Title Defect                                            5.5(A)                                17
----------------------------------------------------------------------------------------------------------------------
Wells                                                         1.1(A)                                2
----------------------------------------------------------------------------------------------------------------------
Working Interest/s                                           5.3(A)(i)                              14
----------------------------------------------------------------------------------------------------------------------
</Table>




<PAGE>
                           PURCHASE AND SALE AGREEMENT


         This Purchase and Sale Agreement (this "Agreement") is entered into
this 8th day of April , 2002, by and between COLORADO INTERSTATE GAS COMPANY a
Delaware corporation ("CIG"), and CIG PRODUCTION COMPANY, L.P., a Delaware
limited partnership ("CIGPC") and EL PASO PRODUCTION GOM INC., a Delaware
corporation, ("El Paso") (CIG, CIGPC , and El Paso are collectively "Seller")
and PIONEER NATURAL RESOURCES USA, INC., a Delaware corporation, ("Buyer" and
"Buyer" includes any qualified party designated by Buyer to acquire all or part
of the Assets but only to the extent related to the Assets acquired by said
designee). Buyer and Seller are collectively referred to herein as the "Parties"
and sometimes individually referred to as a "Party."

                                    RECITALS:

A.       Seller desires to sell to Buyer, or Buyer's designee, all of its oil,
         gas and mineral properties in the West Panhandle Field, Texas and other
         certain properties and assets on the terms and conditions set forth in
         this Agreement.

B.       Seller and Buyer (and/or Seller's and Buyer's affiliates) are parties
         to certain agreements and other instruments related to certain of such
         properties and assets located in Texas ("'B' Contract"), which
         agreements and other instruments are identified on Exhibit "A" to this
         Agreement ("'B' Contract Documents").

C.       Seller also owns certain properties and assets located in Oklahoma,
         offshore Gulf of Mexico and Kansas.

D.       Buyer desires to purchase or have its designee purchase from Seller
         such Texas, Oklahoma, Gulf of Mexico and Kansas assets on the terms and
         conditions set forth in this Agreement.

E.       Buyer and CIG contemplate entering into a Purchase and Sale Agreement
         for the purchase and sale of CIG's West Panhandle gas gathering system.

                                   WITNESSETH:

         In consideration of the mutual agreements contained in this Agreement,
Buyer and Seller agree as follows:

1.       SALE AND PURCHASE OF THE ASSETS.

1.1      Acquired Assets. Subject to the terms and conditions of this Agreement,
         Seller agrees to sell, convey and deliver to Buyer and Buyer agrees to
         purchase and acquire or cause its designee to purchase and acquire from
         Seller all of Seller's right, title and interest in and to the
         following (collectively, the "Assets"):

                                                                               1
<PAGE>

         (A)      All of the leasehold interests, royalty interests, working
                  interests, net revenue interests, overriding royalty
                  interests, payments out of production, reversionary rights,
                  surface fee, mineral fee, and contractual rights to production
                  in and to (i) those interests described in the leases, mineral
                  deeds, subleases, assignments and other instruments described
                  in Exhibit 1.1(A)-1 (collectively "Leases"); (ii) those wells
                  described in Exhibit 1.1(A)-2 (the "Wells"); (iii) all
                  easements, rights of way, and other rights, privileges,
                  benefits and powers with respect to the use and occupation of
                  the surface of, and the subsurface depths under, the land
                  covered by the Leases including, but not limited to, those
                  listed on Exhibit 1.1(A)(iii); (iv) all rights in respect of
                  or pertaining to any pooled or unitized acreage located in
                  whole or in part within each Lease, including all Oil and Gas
                  production from the pool or unit allocated to any such Lease
                  and all interests in any wells within the unit or pool
                  associated with such Lease (the "Units"), regardless of
                  whether such unit or pool production comes from wells located
                  on or off of the boundaries of the Leases.

         (B)      All of the oil and gas and associated hydrocarbons ("Oil and
                  Gas") and all other substances in and under or otherwise
                  attributable that are covered by the Leases and the Units or
                  produced from the Wells.

         (C)      To the extent assignable and applicable to the Assets, all
                  licenses, servitudes, gas purchase and sale contracts
                  (including interests and rights, if any, with respect to any
                  prepayments, take-or-pay, buydown and buyout agreements) and
                  casinghead gas "service agreements" to the extent that the
                  same pertain or relate to periods after the Effective Time, as
                  hereinafter defined, crude purchase and sale agreements,
                  farmin agreements, farmout agreements, bottom hole agreements,
                  acreage contribution agreements, operating agreements, unit
                  agreements, processing agreements, options, leases of
                  equipment or facilities, joint venture agreements, pooling
                  agreements, transportation agreements, rights-of-way and other
                  contracts, agreements and rights, which are owned by Seller,
                  in whole or in part, and are appurtenant to the Leases,
                  subject to their terms (collectively, the "Contracts"). The
                  Contracts include, except as set forth in Section 4.6 and on
                  Exhibits A (items numbered 3, 8, and 9) and 1.2: (i) the 'B'
                  Contract Documents and all of Seller's rights and obligations
                  thereunder; and (ii) the gas purchase, sales, processing and
                  other agreements identified on Exhibit 5.3(B) and all of
                  Seller's rights and obligations thereunder;

         (D)      All of the real, personal and mixed property and facilities
                  located in, on or adjacent to the Leases or used solely in the
                  operation thereof which are owned by Seller, in whole or in
                  part, including, without limitation, well equipment; well
                  cores; casing; tanks; meters; tubing; flowlines; compressors;
                  pumps; motors; electrical systems; fixtures; machinery and
                  other equipment; and all other improvements used in the
                  operation thereof (the "Related Assets").

         (E)      To the extent assignable, all governmental permits, licenses
                  and authorizations, as well as any applications for the same,
                  related to the Leases or the use thereof.

                                                                               2
<PAGE>

         (F)      All production of crude oil, natural gas, condensate or
                  products in storage severed on or after the Effective Time and
                  all other hydrocarbons and other substances and gases produced
                  from or attributable to the Leases or Wells on and after the
                  Effective Time;

         (G)      All tenements, hereditaments and appurtenances belonging to or
                  arising from the Wells and Leases and not otherwise excluded
                  herein;

         (H)      All rights and benefits, intangible and tangible, pertaining
                  to the Assets and all warranties and indemnities in favor of
                  Seller or its predecessors in interest from other parties
                  relating to the Assets;

         (I)      Every other interest in or pertaining to the West Panhandle
                  Field, Texas, and the Assets located in Oklahoma (in the
                  Township-Ranges T5N-R8E, T6N-R8E, T4N-R8E, T4N-R9E, and
                  T3N-R8E) even if not described or not fully or accurately
                  described herein, it being the intent of Seller and Buyer that
                  Buyer receive all of Seller's interest and that Seller retain
                  no such interest except as expressly provided otherwise
                  herein. For the purposes of this Agreement the lands within
                  the geographic boundary of the following fields Killgore Ranch
                  (Red Cave); Panhandle, West; Panhandle, West (Red Cave);
                  Panhandle, West (Red Cave North), the Panhandle Field, and
                  Picher Creek (Red Cave) as of the date hereof (as to all of
                  the above, both 'B' Contract Documents and non-'B' Contract
                  Document properties) comprise the West Panhandle Field.

         (J)      All of Seller's files, records and data (including electronic
                  and physical records and data) relating to the items described
                  in subsections (A), (B), (C), (D), (E), (F), (G), (H), and (I)
                  above, including, without limitation, title records (title
                  curative documents); surveys, maps and drawings; contracts;
                  correspondence; geological and seismic records and
                  information; production records, electric logs, core data,
                  pressure data, decline curves, graphical production curves and
                  all related matters and construction documents except: (i) to
                  the extent the transfer, delivery or copying of such records
                  may be restricted by contract with a third party; (ii) all
                  documents and instruments of Seller that may be protected by a
                  privilege, including without limitation the attorney-client
                  privilege and the work product privilege; and (iii) all
                  accounting and Tax files, books, records, Tax returns and Tax
                  work papers related to such items [collectively the
                  "Records"].

1.2      Excluded Assets.. Notwithstanding the foregoing, the Assets shall not
         include, and there is excepted, reserved and excluded from the purchase
         and sale contemplated herein those items listed in Exhibit 1.2 (the
         "Excluded Assets").

1.3      Assumed Liabilities. Except as provided otherwise in this Agreement, or
         for matters for which an accounting or other adjustment is made
         pursuant to this Agreement, or for which provision is made in another
         agreement, on and after the Closing, Buyer shall assume and agree to
         timely and fully pay, perform and otherwise discharge, all of the
         liabilities and obligations of Seller and its successors, assigns or
         representatives, direct or indirect, known or unknown, asserted or
         unasserted, absolute or contingent, accrued or unaccrued, which

                                                                               3
<PAGE>

         relate, directly or indirectly, to the Assets (other than the Excluded
         Assets), to the extent such liabilities and obligations accrue on or
         after the Effective Time and Buyer also assumes certain liabilities for
         the pre-Effective Time regarding environmental issues as described in
         Article 6 (collectively, the "Assumed Liabilities"). Notwithstanding
         the foregoing, Assumed Liabilities shall not include, and there is
         excepted, reserved and excluded from such liabilities assumed by Buyer,
         the liabilities and obligations for which Seller indemnifies Buyer
         against pursuant to Article 14.

1.4      Retained Liabilities. Except as provided otherwise in this Agreement,
         or for matters which an accounting or other adjustment is made pursuant
         to this Agreement, or for which provision is made in another agreement,
         on and after the Closing Seller shall retain and agree to timely and
         fully pay, perform and otherwise discharge, all of the liabilities and
         obligations of Seller and its, successors, assigns or representatives,
         direct or indirect, known or unknown, asserted or unasserted, absolute
         or contingent, accrued or unaccrued, which relate, directly or
         indirectly, to the Excluded Assets, whenever accruing or occurring and
         Seller also retains certain liabilities for the pre-Effective Time
         regarding environmental issues as described in Article 6 (collectively,
         the "Retained Liabilities"). Notwithstanding the foregoing, Retained
         Liabilities shall not include, and there is excepted, reserved and
         excluded from such liabilities assumed by Seller, the liabilities and
         obligations for which Buyer indemnifies Seller against pursuant to
         Article 14.

1.5      'B' Contract Document Effect. Sections 1.3 and 1.4 above shall take
         into account the gain or benefit which either Party would have received
         and/or the loss or burden for which either Party would be obligated
         under the terms of the 'B' Contract Documents up to the Effective Time
         as if this Agreement had not been executed, except as otherwise
         expressly provided in this Agreement

         1.6. Pre-Effective Time 'B' Contract Rights and Obligations. Except as
         otherwise provided in this Agreement , (including Article 6) Seller and
         Buyer reserve all rights, obligations and claims under the 'B' Contract
         Documents with respect to the period prior to the Effective Time as the
         terms of the 'B' Contract Documents exist on the Effective Time.

2.       PURCHASE PRICE.

2.1      Purchase Price 2.1 The purchase price for the Assets is one hundred
         eighteen million five hundred thousand Dollars ($118,500,000.00) (the
         "Base Purchase Price"), subject to the adjustments provided for herein.

2.2      Adjustments to the Base Purchase Price. At Closing, appropriate
         adjustments to the Base Purchase Price shall be made as follows in
         accordance with Section 4.1 (as adjusted, the "Purchase Price"):

         (A)      The Base Purchase Price shall be adjusted upward by:

                  (i)      an amount equal to the amount of proceeds derived
                           from the sale of Oil and

                                                                               4
<PAGE>

                           Gas, net of royalties, severance and ad valorem taxes
                           actually received by Buyer and directly attributable
                           to the Wells which are, in accordance with generally
                           accepted accounting principles, attributable to
                           Seller pursuant to Section 4.2;


                  (ii)     Asset Taxes which are attributable to periods (or
                           portions thereof) beginning on or after the Effective
                           Time and ending on or before the Closing Date, other
                           than such Taxes which are assumed and paid by Buyer.
                           For purposes of this Agreement, "Asset Tax" shall
                           mean any Tax in the nature of a severance or ad
                           valorem tax which is attributable to any Asset.

                   (iii)   an amount equal to the costs, expenses, royalties and
                           other expenditures (whether capitalized or expensed)
                           paid by Seller in the ordinary course of business in
                           accordance with this Agreement that are attributable
                           and chargeable to the Assets for the period from 9:00
                           a.m. (Central Time) on July 1, 2002 (the "Effective
                           Time") to the Closing Date;

                  (iv)     an amount for operation and maintenance expenses
                           (excluding workover costs, plugging and abandoning
                           costs, and major costs) incurred by Seller with
                           respect to the Assets from and after the Effective
                           Time until Closing determined as follows: (A) as to
                           the Wells located in Texas, a fixed rate per Mcf per
                           active producing Well, as provided in the Pioneer
                           Operating Agreement; and (B) as to the Wells located
                           in Oklahoma and Kansas, a fixed monthly rate per
                           active producing Well of Five Hundred Dollars
                           ($500.00);

                  (v)      all amounts owed to Seller by third parties as of the
                           Effective Time under the Contracts with respect to
                           any Imbalances existing at the Effective Time
                           measured in accordance with Section 4.2 and listed
                           (to the best of Seller's knowledge as of the date
                           therein indicated) on Exhibit 2.2(A)(v), such amounts
                           to be determined for Imbalances by multiplying the
                           Imbalance volume by $1.50 per MMBtu; provided
                           however, no adjustment shall be required for any
                           amounts owed by Buyer to Seller with respect to any
                           Imbalances under the 'B' Contract Production
                           Allocation Agreement dated January 1, 1991, as
                           amended, between Buyer and CIG ("PAA");

                  (vi)     any amount related to a Title Benefit as determined
                           pursuant to Section 5.7;

                  (vii)    interest on the adjusted Base Purchase Price in an
                           amount equal to the lesser of (A) the prime rate of
                           Chase Manhattan Bank, N.A., plus two percent (2%) or
                           (B) the maximum legal rate (the "Interest"), with
                           such Interest accruing from the scheduled Closing
                           Date set forth in Section 3.1 until the actual
                           Closing Date, compounded daily, to the extent that
                           the conditions set forth in Article 11 have been
                           satisfied or waived and Buyer improperly refuses or
                           fails to proceed to Closing on or before the
                           scheduled Closing Date set forth in Section 3.1,
                           other than as a result of Seller's breach of this
                           Agreement or

                                                                               5
<PAGE>

                           Seller's improper refusal or failure to proceed to
                           Closing on or before the scheduled Closing Date;

                  (viii)   [INTENTIONALLY DELETED]

                  (ix)     [INTENTIONALLY DELETED]

                  (x)      any other amount agreed upon in writing by Seller and
                           Buyer; and

                  (xi)     Provided, however, any upward adjustment to the Base
                           Purchase Price shall take into account the gain or
                           benefit which Seller would have received and or loss
                           or burden which Seller would be obligated under the
                           terms of the 'B' Contract Documents up to the
                           Effective Time as if this Agreement had not been
                           executed, except as otherwise provided in this
                           Agreement.

         (B)      The Base Purchase Price shall be adjusted downward by:

                  (i)      an amount equal to the amount of proceeds derived
                           from the sale of Oil and Gas, actually received by
                           Seller and directly attributable to the Wells which
                           are, in accordance with generally accepted accounting
                           principles, attributable to the period of time from
                           and after the Effective Time;

                  (ii)     all helium overriding royalties received by Seller
                           from the processing of volumes of 'B' Contract gas at
                           Buyer's Fain gas processing plant which are
                           attributable to the period of time from and after the
                           Effective Time until Closing;

                  (iii)    an amount equal to all expenditures, liabilities and
                           costs assumed by Buyer relating to the Assets that
                           are unpaid as of the Closing Date and assessed for or
                           attributable to periods of time prior to the
                           Effective Time provided that to the extent the actual
                           amounts cannot be determined prior to the agreement
                           of Buyer and Seller with respect to the Closing
                           Adjustment Statement, a reasonable estimate of such
                           expenditures, liabilities and costs shall be used
                           (and to such extent Buyer shall assume the liability
                           and responsibility for payment of such estimate);

                   (iv)    all amounts owed by Seller to third parties as of the
                           Effective Time until Closing under the Contracts with
                           respect to any Imbalances existing as of the
                           Effective Time and listed on Schedule 2.2(B)(iv) and
                           measured in accordance with Section 4.2, such amounts
                           to be determined for Imbalances by multiplying the
                           Imbalance volume by $1.50 per MMBtu; provided
                           however, no adjustment shall be required for any
                           amounts owed by Seller to Buyer with respect to any
                           Imbalances under the PAA;

                                                                               6
<PAGE>

                  (v)      all amounts related to Title Defects as determined
                           pursuant to Section 5.6, Preferential Rights as
                           determined pursuant to Section 9.3 and Casualty
                           Losses as determined pursuant to Section 15.1; and

                  (vi)     any other amount agreed upon in writing by Seller and
                           Buyer.

                  Provided however, any downward adjustment to the Base Purchase
                  Price shall take into account the loss or exposure which Buyer
                  would have incurred and/or loss or burden for which Buyer
                  would be obligated under the terms of the 'B' Contract
                  Documents, up to the Effective Time as if this Agreement had
                  not been executed, except as provided otherwise in this
                  Agreement.

                  The term "Imbalance" means any Oil and Gas production
                  imbalance existing as of the Effective Time with respect to
                  any of the Assets, together with any related rights or
                  obligations as to future cash and/or gas or product balancing,
                  as a result of, in the case of production imbalances, Seller
                  having taken and sold for Seller's account cumulative
                  production which is greater or less than Seller's Working
                  Interest share in cumulative production.

2.3      Allocation. The Base Purchase Price shall be allocated to the Assets as
         set forth in Exhibit 2.3. Seller and Buyer covenant and agree that the
         values allocated to various portions of the Assets, which are set forth
         on Exhibit 2.3 (singularly with respect to each item, the "Allocated
         Value" and collectively, the "Allocated Values"), shall be binding on
         Seller and Buyer and shall be used only for the purposes of adjusting
         the Base Purchase Price pursuant to Sections 5.6 (relating to Title
         Defects), 9.3 (relating to Preferential Rights) and 15.1 (relating to
         Casualty Losses) and is not intended as a measure of value for any
         other purpose.

2.4 Allocation For Tax Purposes. For the purpose of making the requisite filings
under Section 1060 of Internal Revenue Code of 1986, as amended, (the "Code")
and the regulations thereunder, Seller and Buyer shall, within one
hundred-twenty (120) days following the Closing Date, agree to allocate, in a
manner consistent with the allocation set forth on Exhibit 2.3, the Base
Purchase Price (as adjusted by Section 2.2) and all obligations assumed by Buyer
pursuant to Section 1.3 among the Assets. Seller and Buyer each agree to report
the federal, state and local income and other Tax consequences of the
transactions contemplated herein, and in particular to report the information
required by Section 1060(b) of the Code, and to jointly prepare Form 8594 (Asset
Acquisition Statement under Section 1060) in a manner consistent with such
allocation and shall not take any position inconsistent therewith upon
examination of any Tax return, in any refund claim, in any litigation,
investigation or otherwise unless required to do so by applicable law after
notice to the other Party or with such other Party's prior consent.

                                                                               7
<PAGE>

3.       CLOSING.

3.1      Closing. Subject to the Conditions Precedent set forth at Articles 11
         and 12 and any termination pursuant to Article 13 or Section 15.1, the
         sale and purchase of the Assets ("Closing") shall be held on July 1,
         2002 ("Closing Date"). The Closing will take place at the offices of
         Seller at 2 North Nevada Avenue, Colorado Springs, CO 80903 or such
         other time, place and manner as all the Parties may mutually agree.

3.2      Delivery by Seller.  At Closing, Seller shall deliver to Buyer:

         (A)      Duly executed copies of a Assignment(s) and Bill of Sale,
                  substantially in the form attached hereto as Exhibit 3.2(A)
                  and such other deeds, conveyances or instruments in forms
                  consistent with the terms of this Agreement (which forms
                  Seller shall provide advance copies of to Buyer at least five
                  (5) business days before Closing) effecting the sale,
                  transfer, conveyance and assignment of the Assets to Buyer or
                  Buyer's designee (which for purposes of this Agreement shall
                  be a duly qualified designee of Buyer), in sufficient multiple
                  originals to allow for recording in all appropriate
                  jurisdictions;

         (B)      A Certification of Non-Foreign Status substantially in the
                  form attached hereto as Exhibit 3.2(B).

         (C)      A certificate by an authorized corporate officer of Seller,
                  dated as of the Closing, certifying on behalf of Seller that
                  the conditions set forth in Sections 7.1(A) and 7.1(B) have
                  been fulfilled;

         (D)      A certificate duly executed by the secretary or any assistant
                  secretary of Seller, dated as of the Closing, (i) attaching
                  and certifying on behalf of Seller complete and correct copies
                  of (A) the certificate of incorporation and the bylaws of
                  Seller, each as in effect as of the Closing, (B) the
                  resolutions of the Board of Directors of Seller, if required,
                  authorizing the execution, delivery, and performance by Seller
                  of this Agreement and the transactions contemplated hereby,
                  and (C) any required approval by the stockholders of Seller of
                  this Agreement and the transactions contemplated hereby and
                  (ii) certifying on behalf of Seller the incumbency of each
                  officer of Seller executing this Agreement or any document
                  delivered in connection with the Closing:

         (E)      The list and funds required to be delivered to Buyer pursuant
                  to Section 4.5 herein;

         (F)      Fully executed resignation of operatorship forms or transfer
                  of operatorship forms or such other forms required by
                  governmental agencies to effect the transfer of the Assets;

         (G)      Possession of the Assets; and;

         (H)      A Transition Agreement generally in the form attached as
                  Exhibit 3.2(H) and otherwise modified as mutually agreed,
                  obligating CIG to continue making royalty and tax payments for
                  a period of time after Closing as well as such other
                  agreements

                                                                               8
<PAGE>

                  the Parties mutually agree would assist in the transition of
                  the Assets from Seller to Buyer.

3.3      Delivery by Buyer. At Closing, Buyer shall deliver to Seller or
         Seller's designee the Purchase Price set forth in the Closing
         Adjustment Statement by wire transfer in immediately available funds.
         Seller shall provide wiring instructions to Buyer at least five (5)
         business days prior to the Closing. Buyer shall also provide at
         Closing:

         (A) A certificate by an authorized corporate officer of Buyer, dated as
         of the Closing, certifying on behalf of Buyer that the conditions set
         forth in Sections 8.1(A) and 8.1(B) have been fulfilled;

         (B) A certificate duly executed by the secretary or any assistant
         secretary of Buyer, dated as of the Closing, (i) attaching and
         certifying on behalf of Buyer complete and correct copies of (A) the
         certificate of incorporation and the bylaws of Buyer, each as in effect
         as of the Closing, (B) the resolutions of the Board of Directors of,
         Buyer if required, authorizing, the execution, delivery, and
         performance by Buyer of this Agreement and the transactions
         contemplated hereby, and (C) any required approval by the stockholders
         of Buyer of this Agreement and the transactions contemplated hereby and
         (ii) certifying on behalf of Buyer the incumbency of each officer of
         Buyer executing this Agreement or any document delivered in connection
         with the Closing

3.4      Further Cooperation. At the Closing and thereafter as may be necessary,
         Seller and Buyer shall execute and deliver such other instruments and
         documents and take such other actions as may be reasonably necessary to
         evidence and effectuate the transactions contemplated by this
         Agreement.

3.5      Notice of Breach. Seller and Buyer, until Closing, agree as follows:

         (a)      Buyer shall notify Seller promptly if Buyer believes that any
                  representation or warranty of Seller contained in this
                  Agreement is untrue in any material respect or will be untrue
                  in any material respect as of the Closing Date or that any
                  covenant or agreement to be performed or observed by Seller
                  prior to or on the Closing Date has not been so performed or
                  observed in any material respect.

         (b)      Seller shall notify Buyer promptly if Seller believes that any
                  representation or warranty of Buyer contained in this
                  Agreement is untrue in any material respect or will be untrue
                  in any material respect as of the Closing Date or that any
                  covenant or agreement to be performed or observed by Buyer
                  prior to or on the Closing Date has not been so performed or
                  observed in any material respect.

         (c)      If any such asserted breach of representation, warranty,
                  covenant or agreement shall (if curable) be cured by Closing
                  (or, if Closing does not occur, by the date set forth in

                                                                               9
<PAGE>

                  Section 13.1 (b)), then such breach shall be considered not to
                  have occurred for all purposes of this Agreement

4.       ACCOUNTING ADJUSTMENTS

4.1      Closing Adjustments. With respect to matters that can be determined as
         of the Closing, Seller shall prepare, in accordance with the provisions
         of the Agreement and this Article 4, a statement (the "Closing
         Adjustment Statement") with relevant supporting information setting
         forth each adjustment to the Base Purchase Price submitted by Seller.
         Seller shall submit the Closing Adjustment Statement to Buyer, together
         with all records or data supporting the calculation of amounts
         presented on the Closing Adjustment Statement, no later than five (5)
         business days prior to the scheduled Closing Date. Prior to the
         Closing, Buyer and Seller shall review the adjustments proposed by
         Seller in the Closing Adjustment Statement. Agreed upon adjustments
         shall be taken into account in computing any adjustments to be made to
         the Base Purchase Price at the Closing. When available, actual figures
         will be used for the adjustments at Closing. To the extent actual
         figures are not available, estimates shall be used subject to final
         adjustments as described in Section 4.4 below.

4.2      Strapping and Gauging. Seller or its contract operator will cause the
         Oil and Gas in the storage facilities located on, or utilized in
         connection with, the Leases to be measured, gauged or strapped as of
         the Effective Time. Seller will cause the production meter charts (or
         if such do not exist, the sales meter charts) on the pipelines
         transporting Oil and Gas from the Leases to be read as of such time.
         The Oil and Gas in such storage facilities above the pipeline
         connection or through the meters on the pipelines as of the Effective
         Time shall belong to Seller, and the Oil and Gas placed in such storage
         facilities after the Effective Time and production upstream of the
         aforesaid meters shall belong to Buyer and become part of the Assets.

         4.3      [INTENTIONALLY DELETED]

4.4      Post-Closing Adjustments.

         (A)      A post-closing adjustment statement (the "Post-Closing
                  Adjustment Statement") based on the actual income and expenses
                  shall be prepared and delivered by Seller to Buyer within one
                  hundred twenty (120) days after the Closing, proposing further
                  adjustments to the calculation of the Purchase Price based on
                  the information then available. Seller or Buyer, as the case
                  may be, shall be given access to and shall be entitled to
                  review and audit the other Party's records pertaining to the
                  computation of amounts claimed in such Post-Closing Adjustment
                  Statement.

         (B)      Within sixty (60) days after receipt of the Post-Closing
                  Adjustment Statement, Buyer shall deliver to Seller a written
                  statement describing in reasonable detail its objections (if
                  any) to any amounts or items set forth on the Post-Closing
                  Adjustment Statement. If Buyer does not raise objections
                  within such period, then the Post-

                                                                              10
<PAGE>

                  Closing Adjustment Statement shall become final and binding
                  upon the Parties at the end of such period.

         (C)      If Buyer raises objections, the Parties shall negotiate in
                  good faith to resolve any such objections. If the Parties are
                  unable to resolve any disputed item within sixty (60) days
                  after Buyer's delivery of its objections to the Post-Closing
                  Adjustment Statement, any such disputed item shall be
                  submitted to a nationally recognized independent accounting
                  firm mutually agreeable to the Parties who shall be instructed
                  to resolve such disputed item within thirty (30) days. The
                  resolution of disputes by the accounting firm so selected
                  shall be set forth in writing and shall be conclusive, binding
                  and non-appealable upon the Parties and the Post-Closing
                  Adjustment Statement shall become final and binding upon the
                  Parties on the date of such resolution. The fees and expenses
                  of such accounting firm shall be paid one-half by Buyer and
                  one-half by Seller.

         (D)      After the Post-Closing Adjustment Statement has become final
                  and binding on the Parties, Seller or Buyer, as the case may
                  be, shall - within ten (10) days thereafter - pay to the other
                  such sums as are due to settle accounts between the Parties
                  due to differences between the estimated Purchase Price paid
                  pursuant to the Closing Adjustment Statement and the actual
                  Purchase Price set forth on the Post-Closing Adjustment
                  Statement.

4.5      Suspended Funds. At least ten (10) days prior to the Closing, Seller
         shall provide to Buyer a listing showing all proceeds from production
         through March 2002 attributable to the Leases which are currently held
         in suspense and shall transfer to Buyer at Closing all of those
         suspended proceeds. UPON AND AFTER CLOSING, Buyer shall be responsible
         for proper distribution of all the suspended proceeds to the extent
         turned over to it by Seller, to the parties lawfully entitled to them
         AND ANY CLAIMS RELATED THERETO, and BUYER hereby agrees, ON AND AFTER
         CLOSING, to indemnify, defend and hold harmless Seller from and against
         any and all claims, liabilities, losses, costs and expenses arising out
         of or relating to BUYER'S HANDLING OF those suspended proceeds PAID TO
         IT BY SELLER.

4.6      Audit Adjustments. Buyer and Seller waive all rights to "true up"
         adjustments and audit for year 2002 to the Administrative Fee
         ("Administrative Fee") under the Operating Agreement dated January 8,
         1988, as amended, between Buyer, Seller and CIGPC ("Pioneer Operating
         Agreement"). For all periods prior to 2002, Buyer and Seller retain all
         rights to adjustments to charges and volumes that may be due one
         another under any other 'B' Contract Document but all audits must be
         completed and report submitted on or before December 31, 2002, however,
         during the audit process Seller shall provide timely responses to
         Buyer's requests for information related to said audit. Seller retains
         all rights to adjustments resulting from any other operating agreement
         and other audit claims asserted against third party operators on
         transactions occurring prior to the Effective Time. Any credit received
         by Buyer pertaining to such an audit claim shall be paid to Seller
         within thirty (30) days after receipt.

                                                                              11
<PAGE>

         4.7 Asset Tax Refunds. Refunds of Asset Taxes paid (or to the extent
         payable but not paid due to offset against other Taxes) with respect to
         or attributable to the Assets shall be promptly paid by the Party
         receiving the benefit of the payment or offset as follows: (i) to
         Seller and distributed pursuant to the 'B' Contract Documents if
         attributable to Asset Taxes with respect to any Tax year or portion
         thereof ending on or before the Effective Time; and (ii) to Buyer if
         attributable to Asset Taxes with respect to any Tax year or portion
         thereof beginning from and after the Effective Time.

         4.8 Capital Expenditures. From and after the date of this Agreement
         until Closing, as to any actual or proposed capital expenditures with
         respect to the Assets located in or pertaining to the West Panhandle
         Field, should either CIG or Pioneer propose work requiring "Capital
         Expenditures" under the terms of the Pioneer Operating Agreement, then
         the following shall apply notwithstanding any contrary provision
         contained in the Pioneer Operating Agreement or any other 'B' Contract
         Document. The Party proposing such work shall undertake it at its sole
         cost and expense and such Party waives all rights to recover any
         portion of such costs from the other Party. Provided, however, both CIG
         and Buyer shall share, pursuant to the Pioneer Operating Agreement, the
         costs of a Capital Expenditure that, in Buyer's good faith judgment as
         a prudent operator is (i) required by regulation or other law (e.g.
         environmental, safety, etc.) or (ii) necessary in order to retire a
         fixed asset. Provided however, if this Agreement is terminated prior to
         Closing then the Parties shall be restored to their rights and
         obligations under Pioneer Operating Agreement and other 'B' Contract
         Documents and the foregoing provision shall have no further effect.

         4.9 Cooperation. Each Party covenants and agrees to promptly inform the
         other with respect to amounts owing under Sections 4.4, 4.6, 4.7, 4.8
         and this 4.9 hereof. Further, upon and after Closing and subject to and
         except as provided otherwise under the terms of this Agreement and
         except to the extent for which adjustments or an accounting under this
         Agreement has been made, all monies, refunds, proceeds, receipts,
         credits, receivables, accounts and income attributable to the Assets
         conveyed hereunder (a) for all periods of time from and after the
         Effective Time shall be the property and entitlement of Buyer, and, to
         the extent received by Seller after the Effective Time, Seller shall
         fully disclose and account therefore to Buyer promptly, and (b) for the
         period of time prior to the Effective Time shall be the sole property
         and entitlement of Seller and to the extent received by Buyer after the
         Effective Time, Buyer shall fully disclose and account therefore to
         Seller promptly and, similarly, (c) all operating expenses and capital
         expenditures (except as provided in Section 4.8) incurred in the
         ownership and operation of the Assets in the ordinary course of
         business prior to the Effective Time shall be the sole responsibility
         of Seller and Seller shall promptly pay, or if paid by Buyer, promptly
         reimburse Buyer for same and (d) to the extent incurred in the
         ownership or operation of the Assets in ordinary course of business
         after the Effective Time shall be the sole obligation of Buyer and
         Buyer shall promptly pay, or if paid by Seller promptly reimburse
         Seller for same. Notwithstanding the foregoing sentences in this
         Section 4.9, this Section 4.9 shall take into account the gain or
         benefit which either Party would have received and/or the loss or
         burden for which either Party would be obligated under the terms of the
         'B' Contract Documents up to the Effective Time as if this Agreement
         had not been

                                                                              12
<PAGE>

         executed except as provided otherwise in this Agreement.

4.10     [INTENTIONALLY DELETED]

5.       DUE DILIGENCE; TITLE MATTERS.

5.1      General Access.  Beginning on the second business day after the date of
         this Agreement and ending on the 14th day prior to Closing, Seller
         shall:

         (A)      Give Buyer and its representatives, employees, consultants,
                  independent contractors, attorneys and other advisors
                  reasonable access to the Leases (to the extent same are Seller
                  operated) and other Assets and reasonable access by telephone
                  or in person to Seller's personnel with knowledge of the
                  Assets or operations thereof (including, but not limited,
                  division orders, land administration, accounting, regulatory,
                  and measurements) during regular office hours for any and all
                  inspections and investigations and to the extent such contact
                  with Seller's personnel does not unreasonably interfere with
                  the ongoing operations of Seller.

         (B)      Use reasonable efforts to obtain and submit to Buyer or its
                  representatives as promptly as practicable, copies of such
                  documents as Buyer may reasonably request.

         (C)      Furnish to Buyer all other information with respect to the
                  Assets as Buyer may from time to time reasonably request,
                  unless Seller is prohibited therefrom by any agreement,
                  contract, applicable privilege, obligation or duty by which it
                  is bound or by the necessity of any third party approval;
                  provided that, if requested by Buyer, Seller shall use
                  reasonable efforts to obtain the waiver of any such
                  prohibition or the granting of any such approval.

5.2      Seller's Title.

         (A)      The documents to be executed and delivered by Seller to Buyer
                  transferring the Assets to Buyer shall be subject to the
                  Permitted Encumbrances and shall be substantially in the form
                  set forth in Exhibit 3.2(A) modified to conform to this
                  Agreement, recognizing however, that some instruments may be
                  in or on a form required by governmental agencies. Seller
                  shall warrant and defend unto Buyer the title to the Assets as
                  Good and Marketable against every person lawfully claiming the
                  Assets or any part thereof, by, through or under Seller, but
                  not otherwise. However, all of Seller's interests in the
                  Assets are to be sold AS IS AND WHERE IS AND WITHOUT WARRANTY
                  OF MERCHANTABILITY, CONDITION OR FITNESS FOR A PARTICULAR
                  PURPOSE, EITHER EXPRESS OR IMPLIED.

         (B)      Buyer acknowledges and agrees that Seller cannot and does not
                  covenant or warrant that Buyer shall become successor operator
                  of all or any portion of the Assets, since the Assets or
                  portions thereof may be subject to unit, pooling,
                  communization, operating or other agreements which control the
                  appointment of a successor operator.

                                                                              13
<PAGE>

                  At Closing, Seller shall resign as operator of all the Assets
                  it operates and support Buyer's efforts to become operator of
                  such Assets.

5.3      Good and Marketable Title.  As used herein the term "Good and
         Marketable" title shall mean:

         (A)      As to each of the Wells, that record title or operating rights
                  of Seller which:

                  (i)      entitles Seller to receive from each Well not less
                           than the "Working Interests" shown in Exhibit
                           1.1(A)-2, less royalties and overriding royalties, as
                           the "Net Revenue Interest" of all Oil and Gas
                           produced, saved and marketed from each Well and of
                           all Oil and Gas produced, saved and marketed from any
                           unit of which each Well is a part and allocated to
                           such Well; and

                  (ii)     obligates Seller to bear a percentage of the costs
                           and expenses relating to the maintenance and
                           development of, and operations relating to, each Well
                           not greater than the "Working Interest" shown in
                           Exhibits 1.1(A)-2.

         (B)      That title of Seller to the Assets:

                  (i)      at Closing, is free and clear of liens and
                           encumbrances (except for Permitted Encumbrances as
                           defined in subsection (ii) below) and (a) with
                           respect to real property interests to be transferred
                           to Buyer, real property interests are of record (or
                           deemed to be of record, constructively or otherwise)
                           in the relevant counties or governmental offices; and
                           (b) with respect to any Asset subject to Preferential
                           Rights and consent rights, such rights have been
                           waived and consents obtained from all necessary third
                           parties;

                  (ii)     as used herein the term "Permitted Encumbrances"
                           shall mean any one (1) or more of the following
                           described below or created or described in documents
                           described below:

                           (1)      The terms and conditions of the Leases,
                                    including without limitation lessors'
                                    royalties, overriding royalties, net profits
                                    interests, carried interests, production
                                    payments, reversionary interests and similar
                                    burdens, if the net cumulative effect of the
                                    burdens does not operate to increase the
                                    Working Interest (without a corresponding
                                    proportional increase in the net revenue
                                    interest) or reduce the interest of Seller
                                    with respect to all Oil and Gas produced
                                    from any Well below the Net Revenue Interest
                                    for such Well set forth in Exhibit 1.1(A)-2;

                           (2)      The terms and provisions of the 'B' Contract
                                    Documents and the gas purchase, sales,
                                    processing and other agreements identified
                                    on Exhibit 5.3(B);


                                                                              14
<PAGE>

                           (3)      [INTENTIONALLY DELETED]

                           (4)      Except as provided in Exhibit 5.3 (B), the
                                    sales contracts terminable without penalty
                                    upon no more than thirty (30) days notice to
                                    the purchaser;

                           (5)      Preferential Rights and required third party
                                    consents to assignment and similar
                                    agreements with respect to which waivers or
                                    consents are obtained from the appropriate
                                    parties, or the appropriate time period for
                                    asserting any such right has expired without
                                    an exercise of the right;

                           (6)      Materialman's, mechanic's, repairman's,
                                    employee's, contractor's, operator's and
                                    other similar liens or charges arising in
                                    the ordinary course of business for
                                    obligations that are not delinquent or that
                                    will be paid and discharged in the ordinary
                                    course of business, or if delinquent, that
                                    are being contested in good faith by
                                    appropriate action and which are listed on
                                    Exhibit 5.3(B)(ii)(6);

                           (7)      All rights to consent by, required notices
                                    to, filings with, or other actions by
                                    governmental entities in connection with the
                                    sale or conveyance of oil and gas leases or
                                    interests therein if they are routinely
                                    obtained subsequent to the sale or
                                    conveyance;

                           (8)      Easements, rights-of-way, servitudes,
                                    permits, surface leases and other rights in
                                    respect of surface operations that do not
                                    materially interfere with the oil and gas
                                    operations to be conducted on any Well or
                                    Lease or materially increase the costs of
                                    operating or administering any such Well or
                                    Lease;

                           (9)      All operating agreements, unit agreements,
                                    unit operating agreements, pooling
                                    agreements and pooling designations
                                    affecting the Assets that are either (i) of
                                    record in Seller's chain of title or (ii)
                                    reflected or referenced in Seller's files
                                    that individually or in the aggregate are
                                    not such as to materially interfere with the
                                    current and future operation, (except due to
                                    the conduct of Buyer) value or use of any of
                                    any Well, Lease or the Assets, do not and
                                    will not prevent Buyer from receiving at any
                                    time the proceeds of production from any of
                                    the Wells, do not and will not reduce the
                                    interest of Seller with respect to all Oil
                                    and Gas produced from any Well below the Net
                                    Revenue Interest set forth in Exhibit
                                    1.1(A)-2 for such Well, and/or do not and
                                    will not materially increase the portion of
                                    the costs and expenses relating to any Well
                                    that Seller is obligated to pay above the
                                    Working Interest set

                                                                              15
<PAGE>

                                    forth in Exhibit 1.1(A)-2 for such Well
                                    (without a proportionate increase in Net
                                    Revenue Interest);

                           (10)     Conventional rights of reassignment prior to
                                    release or surrender requiring notice to the
                                    holders of the rights;

                           (11)     All rights reserved to or vested in any
                                    governmental, statutory or public authority
                                    to control or regulate any of the Assets in
                                    any manner, and all applicable laws, rules
                                    and orders of governmental authority;

                           (12)     All agreements affecting the Assets that are
                                    of record in Seller's chain of title, or are
                                    reflected or referenced in Seller's files
                                    that individually or in the aggregate are
                                    not such as to materially interfere with the
                                    current and future operation( except due to
                                    the action of Buyer) value or use of any of
                                    any Well, Lease or the Assets, do not and
                                    will not prevent Buyer from receiving at any
                                    time the proceeds of production from any of
                                    the Wells, do not and will not reduce the
                                    interest of Seller with respect to all Oil
                                    and Gas produced from any Well below the Net
                                    Revenue Interest set forth in Exhibit
                                    1.1(A)-2 for such Well, and/or do not and
                                    will not materially increase the portion of
                                    the costs and expenses relating to any Well
                                    that Seller is obligated to pay above the
                                    Working Interest set forth in Exhibit
                                    1.1(A)-2 for such Well (without a
                                    proportionate increase in Net Revenue
                                    Interest);

                           (13)     All other liens, charges, encumbrances,
                                    contracts, agreements, instruments,
                                    obligations, defects and irregularities
                                    affecting the Assets that individually or in
                                    the aggregate are not such as to materially
                                    interfere with the current and future
                                    operation,( except due to the conduct of
                                    Buyer) value or use of any of any Well,
                                    Lease or the Assets, do not and will not
                                    prevent Buyer from receiving at any time the
                                    proceeds of production from any of the
                                    Wells, do not and will not reduce the
                                    interest of Seller with respect to all Oil
                                    and Gas produced from any Well below the Net
                                    Revenue Interest set forth in Exhibit
                                    1.1(A)-2 for such Well, and/or do not and
                                    will not materially increase the portion of
                                    the costs and expenses relating to any Well
                                    that Seller is obligated to pay above the
                                    Working Interest set forth in Exhibit
                                    1.1(A)-2 for such Well (without a
                                    proportionate increase in Net Revenue
                                    Interest);

                           (14)     Any other Title Defects that Buyer expressly
                                    waives in writing, any Title Defects for
                                    which an adjustment to the Base Purchase
                                    Price is made pursuant to Section 5.6, or
                                    any Title Defects for which the applicable
                                    Asset is not transferred pursuant to this
                                    Agreement due to the election of Seller not
                                    to cure a Title Defect and not transfer such

                                                                              16
<PAGE>

                                    Asset pursuant to Section 5.6 or which are
                                    otherwise deemed to have become Permitted
                                    Encumbrances under this Agreement;

5.4      Waived Purchase Price Adjustments. Buyer waives any claims to adjust
         the Purchase Price for the matters identified in Sections 5.4(A) and
         5.4(B) below:

         (A)      Buyer is aware that a Jerry Nolen has claimed that the Bost
                  "A" lease has terminated due to lack of continuous production,
                  based on one or more brief periods of nonproduction since the
                  mid-1980s. Buyer is also aware that similar claims could be
                  asserted with respect to the Allison, Bost "B," "C," "D, and
                  "3R," Cooper, Coughlin, Johnson, Lubberstedt, Seay and Warrick
                  leases, as each has experienced one or more brief periods of
                  nonproduction since the mid-1980s. Buyer and Seller believe
                  that each of these leases remain in full force and effect and
                  that there are meritorious defenses to any such claims.

         (B)      Buyer is also aware that uncertainty exists as to the exact
                  location of the boundary of the Canadian River in Moore and
                  Potter Counties upstream of the dam that is located at the
                  eastern end of Lake Meredith. As a result, there is
                  uncertainty as to the exact location of Seller's oil and gas
                  leases (Masterson, Bivins and Warrick) that abut the river
                  boundary. This Agreement includes a conveyance to Buyer of all
                  of Sellers' claims, rights and liabilities with respect to
                  such boundary issues.

5.5      Defect Letters.

         (A)      Buyer may, by no later than fourteen (14) days prior to
                  Closing, notify Seller in writing (a "Notice") of any liens,
                  charges, contracts, obligations, encumbrances, defects and
                  irregularities of title which would cause title to all or part
                  of the Assets not to be Good and Marketable as defined in
                  Section 5.3 hereof, or which causes or represents or contains
                  a charge upon the Assets ("Valid Title Defect"), provided that
                  no Valid Title Defect shall be deemed to exist unless (i) the
                  Title Defect Value thereof exceeds the lesser of the ten (10%)
                  per cent of the Allocated Value of the affected Asset or Ten
                  Thousand Dollars ($10,000.00); and, (ii) the aggregate Title
                  Defect Values of all Title Defects satisfying the condition in
                  clause (i) exceed one percent (1%) of the Base Purchase Price
                  (the "Title Defect Hurdle Rate"). A valid Title Defect is a
                  claimed Title Defect which has been determined to valid by (i)
                  mutual agreement of the Parties (ii) the decision of the Title
                  Consult, or (iii) Seller's removal of the Asset from this
                  Agreement. In order to provide Seller a reasonable opportunity
                  to cure any Valid Title Defects prior to Closing, Buyer shall
                  use reasonable efforts to provide the Notice as soon as
                  reasonably possible after becoming aware of or making its
                  determination of the claimed Title Defect. For matters or
                  claims raised by third parties between the 14th day before
                  Closing and Closing, Buyer and Seller shall meet to discuss
                  and resolve said issue.

                                                                              17
<PAGE>

         (B)      In the Notice, Buyer must describe with reasonable detail each
                  alleged Title Defect and the steps required to cure each Title
                  Defect, include Buyer's reasonable estimate of the Title
                  Defect Value attributable to each, and include all data and
                  information in Buyer's possession or control bearing thereon

         (C)      Upon timely delivery of a Notice by Buyer:

                  (i)      Within five (5) days after Seller's receipt of the
                           Title Defects Notice, Seller shall notify Buyer
                           whether Seller agrees with Buyer's claimed Title
                           Defects and/or the proposed Title Defect Values
                           therefore ("Seller's Response"). If Seller does not
                           agree with any claimed Title Defect and/or the
                           proposed Title Defect Value therefor, then the
                           Parties shall enter into good faith negotiations and
                           shall attempt to agree on such matters.

                  (ii)     Within three (3) days after Seller's notice of its
                           cure of a Title Defect, Buyer shall notify Seller
                           whether Buyer agrees with Seller's proposed cure of a
                           Title Defect ("Buyer's Response"). If Buyer does not
                           agree with any such cure, then the Parties shall
                           enter into good faith negotiations and shall attempt
                           to agree on such matters.

                  (iii)    If the Parties cannot reach agreement concerning
                           either the existence of a Valid Title Defect,
                           Seller's or Buyer's proposed cure of a Title Defect,
                           or a Valid Title Defect Value within ten (10) days
                           after Buyer's receipt of Seller's Response or
                           Seller's receipt of Buyer's Response, as applicable,
                           upon either Party's request, the Parties shall
                           mutually agree on and employ an oil and gas attorney
                           with at least ten years recent experience in title
                           examination in the state where the Assets are located
                           ("Title Consultant") to resolve all points of
                           disagreement relating to Title Defects and Title
                           Defect Values, provided that if the Parties cannot
                           agree on an attorney then one having the required
                           qualifications will be appointed by the Chief Justice
                           of the Supreme Court in the state in which the
                           property sits, or his designee. With regard to Assets
                           located in Oklahoma, Gulf of Mexico and Kansas, only,
                           Seller may elect not to proceed to Closing with
                           regard to such Assets and adjust the Base Purchase
                           Price in the amount of the Allocated Value and not
                           submit such matter to arbitration. The Title
                           Consultant shall be a neutral party and shall have no
                           financial interest in the outcome of the Title Defect
                           and shall not have worked for Seller or Buyer in the
                           prior five (5) years.

                  (iv)     Each Party shall present a written statement of its
                           position on the Title Defect and/or Title Defect
                           Value in question to the Title Consultant within five
                           (5) days after the Title Consultant is selected, and
                           the Title Consultant shall make a determination of
                           all points of disagreement in accordance with the
                           terms and conditions of this Agreement within ten
                           (10) business days of receipt of such position
                           statements. The Title Consultant may choose only
                           Seller's or Buyer's position with regard to each
                           separate Title Defect. The determination by the Title
                           Consultant of whether a Title Defect is valid and, if
                           so, its value

                                                                              18
<PAGE>

                           shall be conclusive and binding on the Parties, and
                           shall be enforceable against any Party in any court
                           of competent jurisdiction. Prior to the decision of
                           the Title Consultant, with regard to the Assets
                           located in Texas, the Closing shall be deferred and,
                           if necessary, with regard only to the Assets located
                           in Oklahoma, the Gulf of Mexico and/or Kansas the
                           Closing Date shall be deferred only as to those
                           Assets affected by any unresolved disputes regarding
                           the existence of a Title Defect and/or the Title
                           Defect Value, until the Title Consultant has made a
                           determination of the disputed issues with respect
                           thereto and all subsequent dates and required
                           activities with respect to any such Assets having
                           reference to the Closing Date shall be
                           correspondingly deferred; provided, however, that,
                           unless Seller and Buyer mutually agree to the
                           contrary, the Closing Date shall not be deferred in
                           any event for more than sixty (60) days beyond the
                           scheduled Closing Date in Section 3.1.

                  (v)      The costs of any Title Consultant(s) shall be borne
                           fifty percent (50%) by Seller and fifty percent (50%)
                           by Buyer.

5.6      Effect of Title Defect.

         (A)      In the event Buyer provides Seller with a timely Notice and
                  the Valid Title Defects remaining uncured at Closing exceed
                  the Title Defect Hurdle Rate, Seller may at its sole
                  discretion adjust downward the Base Purchase Price in the
                  amount of Buyer's Title Defect Value(s) of the Asset(s) to
                  which such Title Defects relate and proceed to Closing on all
                  Assets; or

                  (i) Seller, with regard to Assets located in Kansas, Oklahoma,
                  the Gulf of Mexico and Assets not located in or related or
                  pertaining to the West Panhandle Field or subject to the 'B'
                  Contract Documents only, remove the Asset(s) for which Buyer's
                  Notice claims a Title Defect exists and reduce the Base
                  Purchase Price by the Allocated Value of said Asset(s); or

                  (ii) Seller, with regard to Assets in or pertaining to the
                  West Panhandle Field, may remove the Asset(s) for which
                  Buyer's Notice claims a Title Defect exists and reduce the
                  Base Purchase Price by the Allocated Value of said Asset(s),
                  however, such Assets subject to the 'B' Contract Documents on
                  the date of this Agreement shall continue upon removal to be
                  subject to the terms of the 'B' Contract Documents as they
                  exist immediately prior to Closing to the limited extent
                  applicable to said Asset unless and only to the extent as
                  otherwise may be agreed by the Parties; and proceed to Closing
                  on all the other Assets.

                                                                              19
<PAGE>

                   In the alternative, Buyer and Seller may mutually agree to
                  proceed with Closing on those Assets not affected by the
                  outstanding ValidTitle Defects and defer Closing on those
                  other Assets to which a Valid Title Defect relates and for
                  which Seller requests an attempt to cure such Valid Title
                  Defect and for which Buyer shall place into escrow an amount
                  equal to the Allocated Values of the Assets affected by the
                  said Valid Title Defects, which withheld amount shall be paid
                  proportionally to Seller when the Asset affected by any Valid
                  Title Defect is cured or the Valid Title Defect is waived by
                  Buyer and the affected Asset is conveyed from Seller to Buyer.
                  With regard to Assets located in Kansas, Oklahoma and the Gulf
                  of Mexico only, if neither of the above occurs and if Seller
                  later determines it will not cure a Valid Title Defect on or
                  before six (6) months from the Closing Date, the amount in the
                  escrow account attributable to such Valid Title Defect will be
                  returned to Buyer and Seller shall retain such Asset affected
                  by suchValid Title Defect.

         (B)      The diminution in value of an Asset attributable to a Valid
                  Title Defect (the "Title Defect Value") notified in a Notice
                  shall be determined by the following:

                  (i)      if the Valid Title Defect asserted is that the actual
                           Net Revenue Interest attributable to any Well is less
                           than that stated in the applicable Exhibit, then the
                           "Net Revenue Interest Factor" is a fraction, the
                           numerator of which is the difference between the Net
                           Revenue Interest set forth in the applicable Exhibit
                           and the actual Net Revenue Interest, and the
                           denominator of which is the Net Revenue Interest
                           stated in the applicable Exhibit. The Net Revenue
                           Interest Factor will be multiplied by an "Adjustment
                           Factor" to reach the "Total Adjustment Factor". The
                           Adjustment Factor is equal to the Well deliverability
                           (which is equal to the average of the Well's most
                           recent three (3) months wellhead production in
                           thousand cubic feet per day) divided by the
                           difference (which will be deemed zero if negative) of
                           the Well's deliverability and the Well's agreed to
                           producing economic limit (which is 25 thousand cubic
                           feet per day for Wells with an electric or gas
                           powered compressor and 15 thousand cubic feet per day
                           for Wells with a pumping unit and 7.4 thousand cubic
                           feet per day for other wells). Then the Final Defect
                           Value is equal to the "Total Adjustment Factor" times
                           the Allocated Value attributed to the Asset; or

                  (ii)     If the Valid Title Defect represents an obligation,
                           encumbrance, burden or charge upon the affected Asset
                           (including any increase in Working Interest for which
                           there is not a proportionate increase in Net Revenue
                           Interest), the amount of the Title Defect Value is to
                           be determined by taking into account the Allocated
                           Value of the Asset, the portion of the Asset affected
                           by the Title Defect, the legal effect of the Title
                           Defect, the immediate or potential economic and
                           operational effect of the Title Defect over the
                           affected Asset, and the Title Defect Values placed
                           upon the Title Defect by Buyer and Seller.

                  (iii)    Notwithstanding the above, in no event shall the
                           total of the Title Defect Values related to a
                           particular Asset exceed the Allocated Value of such
                           Asset.


                                                                              20
<PAGE>

5.7      Possible Upward Adjustment. Should either Party determine that the
         ownership of any Well entitles Seller to a larger Net Revenue Interest
         (without an increase in the Working Interest) or a smaller Working
         Interest ( without a decrease in the Net Revenue Interest) than that
         set forth on Exhibit 1.1(A)-2, so that Seller's ownership in the Well
         is greater than that contemplated by this transaction, then Seller
         shall notify Buyer as soon as practicable after determining it is
         entitled to a possible upward adjustment but no later than on the 14th
         day prior to the Closing Date of such matter and may propose on the
         Closing Adjustment Statement an upward adjustment to the Base Purchase
         Price to account for such fact (a "Title Benefit") but only to the
         extent each Title Benefit 1) exceeds the lesser of 10% of the Allocated
         Value or Ten Thousand Dollars ($10,000) and 2) only if and to the
         extent the aggregate value of all the Title Benefit exceeds 1% of the
         Base Purchase Price. The validity and amount of such adjustment shall
         be determined in the same manner as provided in Sections 5.6 and
         5.5(C). Seller represents for the purposes of this Section 5.7 that as
         of the date of this Agreement it knows of no instance(s) where it would
         be entitled to a Title Benefit hereunder or any understatement of the
         Net Revenue Interest or overstatement of the Working Interest listed on
         Exhibit 1.1 (A)-2.

5.8      EXCLUSIVE REMEDY. BUYER'S SOLE AND EXCLUSIVE REMEDY AFTER CLOSING WITH
         REGARD TO ANY MATTER PERTAINING TO TITLE OF THE ASSETS SHALL BE
         SELLER'S SPECIAL WARRANTY OF TITLE CONTAINED IN THE ASSIGNMENT AND BILL
         OF SALE OR OTHER INSTRUMENTS EXECUTED BY SELLER AND BUYER PURSUANT TO
         THIS AGREEMENT.

6.       ENVIRONMENTAL ISSUES.

6.1      Resolution of Environmental Issues. Buyer and Seller recognize the
         difficulty of trying to resolve before Closing all the issues
         pertaining to the environmental condition of the Assets and have agreed
         to handle such issues after the Closing as described further in this
         Article 6. In consideration of Seller's covenants contained in this
         Article 6, Buyer waives all rights to make any claims for a Purchase
         Price adjustment based on the environmental condition of the Assets.
         Seller's and Buyer's covenants set forth in this Article 6 shall
         commence at Closing and survive the Closing. The provisions of Article
         6 shall prevail over any conflicting or inconsistent provisions in this
         Agreement subject only to the provision that Seller shall not be
         required to contribute toward the Remediation cost of any Adverse
         Environmental Condition pursuant to this Article 6 to the extent the
         same was caused by Buyer's new operations after the Effective Time or
         as to Section 6.3 below only, if Seller gets a non-appealable judgment
         against Buyer from a court of competent jurisdiction that the basis for
         said Adverse Environmental Condition did not exist, in whole or in
         part, at the Effective Time.

6.2      Seller's $5,000,000 Post-Closing Environmental Contribution. For the
         period beginning at Closing and ending on the fifth anniversary of
         Closing, upon demand by Buyer from time to time, Seller and Buyer shall
         share equally, 50%/50%, Buyer's third party or outside costs or

                                                                              21
<PAGE>

         expenses (or Buyer's internal costs or activities approved by Seller)
         toward the Remediation, investigation, defense or handling of matters
         or claims or actions related thereto for any Adverse Environmental
         Condition or suspected Adverse Environmental Condition, or violation or
         possible violation of Environmental Laws. Seller's maximum aggregate
         contribution to Buyer under this Section 6.2 is five million dollars
         ($5,000,000) and is independent of and in addition to Seller's
         contribution pursuant to 6.3 below. Seller's contribution in this
         Section 6.2 may be applied to any Asset, wherever located. Seller's
         contribution under this Section 6.2 is in addition to that sharing of
         costs by Seller in 6.3 below.

6.3      Buyer's and Seller's 50/50 Sharing of Costs and Expenses for Certain
         Groundwater Matters. In addition to Seller's contribution provide in
         6.2 above, after Closing, upon demand by Buyer from time to time,
         Seller and Buyer shall share equally, 50%/50%, Buyer's third party or
         outside costs (or Buyer's internal costs or activities approved by
         Seller) toward the Remediation,investigation, defense or handling of
         matters or claims or actions related thereto for any instance for which
         (i) Buyer has reasonably determined may constitute a violation of
         Environmental Laws with regard to groundwater, surface or subsurface at
         any depth and such contamination (regardless of the composition of such
         contamination) that may have been or was caused, at any time, by the
         ownership, operation or use of the Assets or any act or omission
         related thereto or such contamination was aggravated thereby, or (ii)
         the Remediation has been ordered by a regulatory agency having
         jurisdiction, or by a court of competent jurisdiction. Groundwater as
         used in this Article 6 does not include water contained in soil that is
         approved by the applicable governmental agency regulating such matter
         to be cleaned up through the application of soil cleanup standards.

6.4      Cooperation and Final Decision. Buyer shall provide Seller with Buyer's
         justification for a proposed action, a description of the background
         and the anticipated costs and method of handling the matter for which
         it is seeking a contribution from Seller pursuant to Section 6.2 and/or
         the sharing of costs in Section 6.3 above, and Buyer and Seller shall
         work in a commercially reasonable manner to determine if they agree on
         the course to be taken with regard to such matter(s), with Buyer having
         the final say, under the standard of a reasonably prudent operator, in
         resolving differences or deciding a course of action in this regard
         between Buyer and Seller.

6.5      Physical Condition of the Assets. Buyer acknowledges that the Assets
         have been used or may have been used for drilling and for gas and
         natural gas liquid production operations and may contain waste
         materials or hazardous substances related to standard oil field
         operations. Physical changes in or under the Assets or adjacent lands
         may have occurred as a result of such uses. The Assets also may contain
         buried pipelines and other equipment, whether or not of a similar
         nature, the locations of which may not now be known by Seller or be
         readily apparent by a physical inspection of the Assets. Buyer
         understands that Seller does not have

                                                                              22
<PAGE>

         the requisite information with which to determine the exact nature or
         condition of the Assets nor the effect any such use has had on the
         physical condition of the Assets

         In addition, Buyer acknowledges that some oil field production
         equipment located on the Assets may contain mercury, asbestos and/or
         naturally-occurring radioactive material ("NORM"). In this regard,
         Buyer expressly understands that NORM may affix or attach itself to
         inside of wells, materials and equipment as scale or in other forms,
         and that wells, materials and equipment located on the Assets described
         herein may contain NORM and that NORM-containing materials may be
         buried or have been otherwise disposed of on the Assets. Buyer also
         expressly understands that special procedures may be required for the
         removal and disposal of mercury, asbestos and NORM from the Assets
         where it is found.

6.6      Inspection and Testing.

         (A)      Prior to Closing, Buyer shall have the right, at its sole cost
                  and risk, to conduct a Phase I environmental assessment of the
                  Assets located in Kansas and Oklahoma to the extent that
                  Seller has the authority to grant such right to Buyer;
                  provided that Seller shall have the right to review and
                  approve any plan to conduct such an environmental assessment,
                  with such approval not to be unreasonably withheld, delayed or
                  conditioned by Seller. Any data obtained shall be immediately
                  provided to Seller, including any reports and conclusions.
                  Seller and Buyer shall keep all information strictly
                  confidential whether or not Closing occurs, except as may be
                  required pursuant to any Environmental Laws.

         (B)      With regard to the Assets located in Kansas and Oklahoma only,
                  Buyer waives and releases all claims against Seller, its
                  parent, subsidiary and affiliated entities, and each of their
                  respective directors, officers, employees, agents and other
                  representatives and their successor and assigns (collectively,
                  the "Seller Group"), for injury to or death of persons, or
                  damage to property, arising in any way from the exercise of
                  rights granted to Buyer in this Agreement hereby or the
                  activities of Buyer or its employees, agents or contractors on
                  the Assets prior to Closing pursuant to this Agreement and
                  BUYER SHALL INDEMNIFY THE SELLER GROUP AGAINST AND HOLD EACH
                  AND ALL OF SAID INDEMNITEES HARMLESS FROM ANY AND ALL LOSS,
                  COST, DAMAGE, EXPENSE OR LIABILITY, INCLUDING ATTORNEY'S FEES,
                  WHATSOEVER ARISING OUT OF (I) ANY AND ALL STATUTORY OR COMMON
                  LAW LIENS OR OTHER ENCUMBRANCES FOR LABOR OR MATERIALS
                  FURNISHED IN CONNECTION WITH SUCH TESTS, SAMPLINGS, STUDIES OR
                  SURVEYS AS BUYER MAY CONDUCT WITH RESPECT TO THE SAIDASSETS;
                  AND (II) ANY INJURY TO OR DEATH OF PERSONS OR DAMAGE TO
                  PROPERTY OCCURRING IN, ON OR ABOUT THE SAID ASSETS AS A RESULT
                  OF SUCH EXERCISE OR ACTIVITIES PRIOR TO CLOSING.

         (C)      "Environmental Laws" means all applicable local, state, and
                  federal laws, rules, regulations, permits and orders
                  regulating or otherwise pertaining to: (i) the use,
                  generation, migration, storage, removal, treatment, remedy,
                  discharge, release,

                                                                              23
<PAGE>

                  transportation, disposal, or cleanup of pollutants,
                  contamination, hazardous wastes, hazardous substances,
                  hazardous materials, toxic substances or toxic pollutants;
                  (ii) surface waters, ground waters, ambient air and any other
                  environmental medium on or off any Lease; or (iii) the
                  environment or health and safety-related matters; including
                  the following as from time to time amended and all others
                  whether similar or dissimilar: the Comprehensive Environmental
                  Response, Compensation, and Liability Act of 1980, as amended
                  by the Superfund Amendments and Reauthorization Act of 1986,
                  the Resource Conservation and Recovery Act of 1976, as amended
                  by the Used Oil Recycling Act of 1980, the Solid Waste
                  Disposal Act Amendments of 1980, and the Hazardous and Solid
                  Waste Amendments of 1984, the Hazardous Materials
                  Transportation Act, as amended, the Toxic Substance Control
                  Act, as amended, the Clean Air Act, as amended, the Clean
                  Water Act, as amended, and all regulations promulgated
                  pursuant thereto.

6.7      Adverse Environmental Conditions. The term "Adverse Environmental
         Condition" means (i) the failure of the Assets or the lands on which
         any of the Assets are located or which are affected by any Assets to be
         in compliance with all applicable Environmental Laws; (ii) the Assets
         or the lands on which any of the Assets are located or which are
         affected by any Asset being subject to any agreements, consent orders,
         decrees or judgments currently in existence based on any Environmental
         Laws that negatively impact the present or future use of any portion of
         the Assets or that require any material change in the present
         conditions of any of the Assets; (iii) the Assets or the lands on which
         any of the Assets are located or pertain being subject to any uncured
         notices of violations of or non-compliance with any applicable
         Environmental Laws; including any item which is disclosed in this
         Agreement or was otherwise disclosed to Buyer; or (iv) any of the
         Assets or the lands on which any of the Assets are located or which are
         affected by the Assets are contaminated, surface or subsurface,
         including with, but not limited to, harmful or potentially harmful
         substances, or which are a current or potential safety hazard.

         EXCEPT AS EXPRESSLY SET FORTH IN THIS AGREEMENT, BUYER IS PURCHASING
         THE ASSETS WITH NO WARRANTIES OF ANY KIND, EXPRESS OR IMPLIED, EITHER
         ORAL OR WRITTEN, MADE BY ANY MEMBER OF THE SELLER GROUP WITH RESPECT TO
         THE PHYSICAL OR ENVIRONMENTAL CONDITION OF THE ASSETS OR WITH RESPECT
         TO THE EXISTENCE OR ABSENCE OF PETROLEUM OR HAZARDOUS SUBSTANCES IN,
         ON, UNDER OR AFFECTING THE ASSETS OR WITH RESPECT TO THE COMPLIANCE OF
         THE ASSETS OR ITS OPERATION WITH ANY LAWS, ORDINANCES OR REGULATIONS OF
         ANY GOVERNMENT OR OTHER BODY. EXCEPT AS EXPRESSLY SET FORTH IN THIS
         AGREEMENT.

         6.8      Definition. The term "Remediate" or "Remediation" means, with
                  respect to any condition of the Assets or the lands on which
                  any of the Assets are located or affect or any Adverse
                  Environmental Condition, the investigation, planning,
                  contracting, undertaking and/or completion of those actions
                  and activities of whatever nature or degree toward the goal of
                  bringing the Assets (or said lands) into compliance with the
                  Environmental Laws.

                                                                              24
<PAGE>

6.9      Remediation. Subject to Section 6.4 of this Agreement, if, after
         Closing, Buyer elects or is ordered by a regulatory agency having
         jurisdiction or a court of competent jurisdiction to Remediate or
         otherwise address an Adverse Environmental Condition, the following
         will govern the Remediation:

         (A)      Buyer shall be responsible for all negotiations and contacts
                  with federal, state, and local agencies and authorities with
                  regard to the Adverse Environmental Condition or Remediation.
                  Unless Seller gives Buyer reasonable notice and a reasonable
                  opportunity to participate jointly with Seller, Seller may not
                  make any independent contacts with any agency, authority, or
                  other non-affiliated third party with respect to the Adverse
                  Environmental Condition or Remediation and shall keep all
                  information regarding the Adverse Environmental Condition
                  and/or Remediation confidential, except in each instance to
                  the extent required by applicable law.

         (B)      Buyer, after reasonable and good faith consultation with
                  Seller may Remediate the Adverse Environmental Condition to
                  the level it deems appropriate, provided that, as to matters
                  subject to Section 6.3 hereof, in no event shall Seller be
                  obligated to pay for costs associated with cleaning up
                  environmental media to the extent beyond (i) the level
                  actually required by applicable Environmental Law or (ii) by a
                  regulatory agency having jurisdiction or (iii) by order of a
                  court having competent jurisdiction, unless Seller has given
                  its written consent before such costs are incurred. Buyer
                  shall provide Seller with copies of invoices of costs incurred
                  and final reports or studies prepared by Buyer regarding such
                  Remediation for which Seller is contributing pursuant to
                  Sections 6.2 and 6.3. Upon Seller's request, Buyer shall also
                  provide all non-privileged draft reports and/or underlying
                  data or analyses thereof regarding such Remediation or
                  cleanup.

7.       REPRESENTATIONS AND WARRANTIES OF SELLER.

7.1      Seller's Representations and Warranties. Subject to the disclosures set
         forth in Exhibits 7.1 (D), (E), (F), (I) and (L), Seller represents and
         warrants [which representations and warranties shall terminate at the
         Closing hereof, except Section 7.1(D) survives Closing for ninety (90)
         days, Sections 7.1(E)and (K) survive for four (4) years after Closing,
         Section 7.1 (G) survives for one (1) year after Closing, Sections
         7.1(H)and (J) survive without time limit after Closing and Section 7.1
         (I) survives Closing for a period lasting until the end of ninety
         (90)days after the expiration of the applicable statutes of limitation]
         on the Effective Date and Closing as follows:

                                                                              25
<PAGE>

         (A)      Status of Incorporation. CIG is a corporation duly
                  incorporated, validly existing and in good standing under the
                  laws of the State of Delaware. CIGPC is a limited partnership
                  duly formed, validly existing and in good standing under the
                  laws of the State of Delaware. El Paso is a corporation duly
                  incorporated, validly existing and in good standing under the
                  laws of the State of Delaware.

         (B)      Authority. Seller has the requisite power and authority to
                  enter into this Agreement, to carry out the transactions
                  contemplated hereby, to transfer the Assets in the manner
                  contemplated by this Agreement, and to undertake all of the
                  obligations of Seller set forth in this Agreement.

         (C)      Validity of Obligations. This Agreement and any documents or
                  instruments delivered by Seller at the Closing shall
                  constitute legal, valid and binding obligations of Seller,
                  enforceable in accordance with their terms.

         (D)      Authorization for Expenditures. Except for Authorizations for
                  Expenditures exchanged between Buyer and Seller prior to the
                  date of this Agreement, with respect to the joint, unit or
                  other operating agreements relating to the Assets, to Seller's
                  knowledge, except as set forth in Exhibit 7.1(D), there are no
                  material outstanding calls or payments under authorities for
                  expenditures for payments relating to the Assets which are due
                  or which Seller has committed to make which have not been
                  made.

         (E)      Contractual Restrictions. Except as set forth in Exhibit
                  7.1(E), Seller has not entered into any contracts for or
                  received prepayments, take-or-pay arrangements, buydowns,
                  buyouts for Oil and Gas, or storage of the same or production
                  payments relating to the Assets which Buyer shall be obligated
                  to honor and make deliveries of Oil and Gas or pay refunds of
                  amounts previously paid under such contracts or arrangements.

         (F)      Litigation. To Seller's knowledge, except as set forth in
                  Exhibit 7.1(F), there is no suit or action pending, arising
                  out of, or with respect to the ownership, operation or
                  environmental condition of the Assets that would have a
                  material adverse affect upon the Assets.

         (G)      Permits and Consents. To Seller's knowledge, with respect to
                  Assets for which Seller is the operator, Seller has (i)
                  acquired all material permits, licenses, approvals and
                  consents from appropriate governmental bodies, authorities and
                  agencies to conduct operations on the Assets in compliance
                  with applicable laws, rules, regulations, ordinances and
                  orders; and (ii) is in material compliance with all such
                  permits, licenses, approvals and consents and with applicable
                  Environmental Laws.


                                                                              26
<PAGE>

         (H)      Broker's Fees. Seller shall retain the obligation or
                  liability, contingent or otherwise, for brokers' or finders'
                  fees in respect of the matters provided for in this Agreement
                  and Buyer shall have no responsibility therefor.

         (I)      Taxes. Except as set forth in Exhibit 7.1(I), (i) Seller has
                  filed or will file prior to Closing (with respect to the
                  Assets) all material Tax returns that are due, (ii) all Taxes
                  (with respect to the Assets) shown to be due on such returns
                  have been paid, or will be paid prior to Closing and (iii)
                  there is no material dispute or claim concerning any Tax
                  liability of the Seller (with respect to the Assets) claimed
                  or raised by any Tax authority in writing. For purposes of
                  this Agreement, the term "Tax" or "Taxes" means any federal,
                  state, local or tribal, income, gross receipts, license,
                  payroll, employment, excise, severance, stamp, occupation,
                  premium, windfall profits, environmental (including taxes
                  under Section 59A of the Code), custom duties, capital stock,
                  franchise, profits, withholding, social security (or similar
                  excises), unemployment, disability, real property, personal
                  property, sales, use, transfer, registration, value added,
                  alternative or add-on minimum, estimated, or other tax of any
                  kind whatsoever, including any interest, penalty or addition
                  thereto, whether disputed or not.

         (J)      All of Seller's Interest. Except as expressly provided
                  otherwise in this Agreement, the Assets to be conveyed to
                  Buyer pursuant to this Agreement represent all of Seller's
                  interest and contractual entitlement to interest in oil and
                  gas leases, wells, overriding royalties or similar interests
                  and rights in Oil and Gas in place and the personal, mixed and
                  real property related thereto West Panhandle Field, Texas,
                  except for (i) certain royalty interests owned by CIG
                  Resources Company, which will be conveyed to Seller before
                  conveyance to Buyer at Closing; and an interest held by by an
                  affiliate of Seller in the 1996 Fain Gas Processing Agreement
                  (which agreement is identified on Exhibit 'A") which interest
                  Buyer may require be assigned to Seller prior to Closing so
                  that such interest may be conveyed to Buyer at Closing. Seller
                  has not entered into any contract or arrangement with
                  affiliates of Seller which creates any entitlement to any
                  interest in oil and gas leases, wells, production, over riding
                  royalties, royalties or similar interest or rights in Oil and
                  Gas in place and the personal, mixed and real property related
                  to the West Panhandle Field.

         (K)      No Unpaid Royalties. Seller has paid, and shall have paid at
                  Closing, all royalties, rentals or similar obligations that
                  are due and payable based on production from or ownership of
                  Seller's interest in the Assets excluding the suspended fund
                  delivered to Buyer pursuant to Section 4.5 at Closing.

         (L)      Valid Agreements. Except as set forth in Exhibit 7.1 (L), and
                  excluding the disclosure in Section 5.4 and disputes between
                  Buyer and Seller under the "B" Contract Documents, all
                  material contracts and agreements constituting a part of the
                  Assets are valid and in full force and effect, and no party is
                  in breach or default, or with the lapse of time or giving of
                  notice or both would be in breach or default, with respect to
                  any of its obligations thereunder and no party has given or
                  threatened to give Seller notice of any default thereunder.


                                                                              27
<PAGE>

7.2      Scope of Representations of Seller.

         (A)      Information About the Assets. Except as expressly set forth in
                  this Agreement, Seller disclaims all liability and
                  responsibility for any representation, warranty, statements or
                  communications (orally or in writing) to Buyer, including any
                  information contained in any opinion, information or advice
                  that may have been provided to Buyer by any member of the
                  Seller Group, or any consultant, engineer or engineering firm,
                  trustee, partner, member, beneficiary, stockholder or
                  contractor of Seller pursuant to this Agreement, wherever and
                  however made, including those made in any data room expressly
                  made available to Buyer and any supplements or amendments
                  thereto or during any negotiations with respect to this
                  Agreement or any confidentiality agreement previously executed
                  by the Parties with respect to the Asset. EXCEPT AS SET FORTH
                  IN ARTICLE 7 OF THIS AGREEMENT, SELLER MAKES NO WARRANTY OR
                  REPRESENTATION, EXPRESS, STATUTORY OR IMPLIED, AS TO (i) THE
                  ACCURACY, COMPLETENESS OR MATERIALITY OF ANY DATA, INFORMATION
                  OR RECORDS FURNISHED TO BUYER IN CONNECTION WITH THE ASSETS OR
                  OTHERWISE CONSTITUTING A PORTION OF THE ASSETS; (ii) THE
                  PRESENCE, QUALITY AND QUANTITY OF HYDROCARBON RESERVES (IF
                  ANY) ATTRIBUTABLE TO THE ASSETS, INCLUDING WITHOUT LIMITATION
                  SEISMIC DATA AND SELLER'S INTERPRETATION AND OTHER ANALYSIS
                  THEREOF; (iii) THE ABILITY OF THE ASSETS TO PRODUCE
                  HYDROCARBONS, INCLUDING WITHOUT LIMITATION PRODUCTION RATES,
                  DECLINE RATES AND RECOMPLETION OPPORTUNITIES; (iv) IMBALANCE
                  OR PAYOUT ACCOUNT INFORMATION, ALLOWABLES, OR OTHER REGULATORY
                  MATTERS; (v) THE PRESENT OR FUTURE VALUE OF THE ANTICIPATED
                  INCOME, COSTS OR PROFITS, IF ANY, TO BE DERIVED FROM THE
                  ASSETS; (vi) THE ENVIRONMENTAL CONDITION OF THE ASSETS; (vii)
                  ANY PROJECTIONS AS TO EVENTS THAT COULD OR COULD NOT OCCUR;
                  (viii) THE TAX ATTRIBUTES OF ANY ASSET; (ix) ANY OTHER MATTERS
                  CONTAINED IN OR OMITTED FROM ANY INFORMATION OR MATERIAL
                  FURNISHED TO BUYER BY THE SELLER GROUP OR OTHERWISE
                  CONSTITUTING A PORTION OF THE ASSETS; AND (x) THE COMPLETENESS
                  OR ACCURACY OF THE INFORMATION CONTAINED IN ANY EXHIBIT
                  HERETO. ANY DATA, INFORMATION OR OTHER RECORDS FURNISHED BY
                  SELLER ARE PROVIDED TO BUYER AS A CONVENIENCE AND BUYER'S
                  RELIANCE ON OR USE OF THE SAME IS AT BUYER'S SOLE RISK.

                                                                              28
<PAGE>

         (B)      Independent Investigation. Buyer acknowledges that it has, or
                  by Closing will have, made its own independent investigation,
                  analysis and evaluation of the transactions contemplated by
                  this Agreement (including Buyer's own estimate and appraisal
                  of the extent and value of Seller's Oil and Gas reserves
                  attributable to the Assets and an independent assessment and
                  appraisal of the environmental risks and liabilities
                  associated with the acquisition of the Assets). Buyer assumes
                  it will have prior to Closing, access to all information
                  necessary to perform its investigation and, based on such
                  assumption, Buyer has not relied and will not rely on any
                  representations by Seller other than those expressly set forth
                  in this Agreement.

         (C)      Waiver of Deceptive Trade Practices Acts. BUYER WAIVES ITS
                  RIGHTS UNDER THE DECEPTIVE TRADE PRACTICES ACT SECTION 17.41
                  et seq., TEXAS BUSINESS & COMMERCE CODE, A LAW THAT GIVES
                  CONSUMERS SPECIAL RIGHTS, AND UNDER SIMILAR STATUTES ADOPTED
                  IN OTHER STATES, TO THE EXTENT THEY HAVE APPLICABILITY TO THE
                  TRANSACTIONS CONTEMPLATED BY THIS AGREEMENT. AFTER
                  CONSULTATION WITH AN ATTORNEY OF ITS SELECTION, BUYER CONSENTS
                  TO THIS WAIVER.

8.       REPRESENTATIONS AND WARRANTIES OF BUYER.

8.1      Buyer's Representations and Warranties. Buyer represents and warrants
         [which representations and warranties shall not survive the Closing
         (except that Section 8.1(F) survives Closing for four (4) years after
         Closing and Sections 8.1(E) and (H) survive without time limitation
         after Closing] on the Effective Date and Closing as follows:

         (A)      Status of Incorporation. Buyer is a corporation duly
                  incorporated, validly existing and in good standing under the
                  laws of the State of Delaware.

         (B)      Corporate Authority. Buyer has the corporate power and
                  authority to enter into this Agreement, to carry out the
                  transactions contemplated hereby and to undertake all of the
                  obligations of Buyer set out in this Agreement.

         (C)      Validity of Obligations. The consummation of the transactions
                  contemplated by this Agreement will not in any respect
                  violate, nor be in conflict with, any provision of Buyer's
                  charter, by-laws or other governing documents, or any
                  agreement or instrument to which Buyer is a party or is bound,
                  or any judgment, decree, order, statute, rule or regulation
                  applicable to Buyer (subject to governmental consents and
                  approvals customarily obtained after the Closing). This
                  Agreement constitutes legal, valid and binding obligations of
                  Buyer, enforceable in accordance with its terms.

         (D)      Qualification and Bonding. Buyer represents and warrants that
                  it is in compliance with the bonding and liability insurance
                  requirements in accordance with all applicable state or
                  federal laws or regulations and that it is and henceforth will
                  continue to be qualified to own any federal, Indian or state
                  oil and gas leases that constitute part of the Assets.

                                                                              29
<PAGE>

         (E)      Non-Security Acquisition. Buyer hereby represents to Seller
                  that it intends to acquire the Assets for its own benefit and
                  account and that it is not acquiring said Assets with the
                  intent of distributing fractional undivided interests thereof
                  such as would be subject to regulation by federal or state
                  securities laws, and that if, in the future, it should sell,
                  transfer or otherwise dispose of said Assets or fractional
                  undivided interests therein, it will do so in compliance with
                  any applicable federal and state securities laws.

         (F)      Evaluation. Buyer represents that by reason of Buyer's
                  knowledge and experience in the evaluation, acquisition and
                  operation of oil and gas properties, Buyer has evaluated the
                  merits and risks of purchasing the Assets from Seller and has
                  formed an opinion based solely upon Buyer's knowledge and
                  experience and not upon any representations or warranties by
                  the Seller Group.

         (G)      Financing. Buyer has sufficient cash, available lines of
                  credit or other sources of immediately available funds to
                  enable it to pay the Purchase Price to Seller at the Closing.

         (H)      Broker's Fees. Buyer has incurred no obligation or liability,
                  contingent or otherwise, for brokers' or finders' fees in
                  respect of the matters provided for in this Agreement, or, if
                  any such obligation or liability exists, it shall remain an
                  obligation of Buyer, and Seller shall have no responsibility
                  therefor.

9.       CERTAIN AGREEMENTS OF SELLER. Seller agrees and covenants (which
         covenants shall, with the exception of those set forth in Section 9.1 ,
         survive Closing) that, unless Buyer shall have otherwise agreed in
         writing, the following provisions shall apply:

9.1      Maintenance of Assets. From the date of this Agreement until Closing,
         Seller agrees that, for those Wells which it operates, it shall:

         (A)      Administer and operate the Leases and Wells in accordance with
                  the applicable Leases and operating agreements.

         (B)      Not introduce any new methods of management, operation or
                  accounting with respect to any or all of the Assets.

         (C)      Use commercially reasonable efforts to maintain and keep the
                  Assets in full force and effect; and fulfill all contractual
                  or other covenants, obligations and conditions imposed upon
                  Seller with respect to the Assets, including, but not limited
                  to, payment of royalties, delay rentals, shut-in gas royalties
                  and any and all other required payments.

         (D)      Except to the extent contractually required, necessary or
                  advisable to avoid forfeiture or penalties, not enter into
                  agreements to drill new wells or to rework, plug back,

                                                                              30
<PAGE>

                  deepen, plug or abandon any Well, nor commence any drilling,
                  reworking or completing or other operations on the Leases
                  which requires expenditures exceeding twenty five Thousand
                  Dollars ($25,000.00) for each operation (except for emergency
                  operations and operations required under presently existing
                  contractual obligations) without obtaining the prior written
                  consent of Buyer (which consent shall not be unreasonably
                  withheld, delayed or conditioned); provided that the terms of
                  this paragraph (D) shall not apply to any expenditures of
                  Seller which will not be charged to Buyer.

         (E)      Not voluntarily relinquish its position as operator to anyone
                  other than Buyer with respect to any of the Wells or
                  voluntarily abandon any of the Wells other than as required
                  pursuant to the terms of a Lease or by regulation.

         (F)      Not, without the prior written consent of Buyer (which consent
                  shall not be unreasonably withheld, delayed or conditioned),
                  (i) enter into any agreement or arrangement (other than one
                  constituting a Permitted Encumbrance) transferring, selling or
                  encumbering any of the Assets (other than in the ordinary
                  course of business, including ordinary course sales of
                  production, inventory or salvage or with respect to any Assets
                  with a value less than $25,000 or pursuant to any agreements
                  existing on the date hereof); (ii) grant any preferential or
                  other right to purchase or agree to require the consent of any
                  party not otherwise required to consent to the transfer and
                  assignment of the Assets to Buyer; (iii) enter into any new
                  sales contracts or supply contracts which cannot be cancelled
                  upon thirty (30) days prior notice; or (iv) incur or agree to
                  incur any contractual obligation or liability (absolute or
                  contingent) with respect to the Assets except as otherwise
                  provided herein (including ordinary course sales of
                  production, inventory or salvage or with respect to any Assets
                  with a value less than $25,000 or pursuant to any disclosed
                  Authorization for Expenditures covering the Assets).

         (G)      To the extent known to Seller, provide Buyer with written
                  notice of (i) any claims, demands, suits or actions made
                  against Seller which materially affect the Assets; or (ii) any
                  proposal from a third party to engage in any material
                  transaction (e.g., a farmout) with respect to the Assets.

         (H)      Not sell, transfer, assign, convey, remove or otherwise
                  dispose of any of the Assets subject to Seller's control,
                  other that (a) oil, gas and other hydrocarbons produced, saved
                  and sold in the ordinary course of business, or (b) personal
                  property and equipment which is replaced with property and
                  equipment of comparable or better value and utility in the
                  ordinary and routine maintenance and operation of the Assets.

                  9.2 Consents or Assignments. Seller shall exercise reasonable
         commercial efforts to obtain all such permissions, approvals and
         consents by governmental authorities and others which are reasonably
         obtainable by Closing and are required to vest Good and Marketable
         title to the Assets in Buyer or as may be otherwise reasonably
         requested by Buyer. Seller will execute all necessary or appropriate
         transfer orders (or letters in lieu thereof) designating Buyer as the
         appropriate party for payment effective as of the Closing

                                                                              31
<PAGE>

         Date. Any failure to obtain such permissions, approvals and consents
         that are required to vest Good and Marketable title to the Assets shall
         be deemed a Title Defect and the procedures set forth in Section 5.6
         shall apply. If any of the foregoing items listed in Sections 1.1(C)
         and (E) are not assignable, Seller shall hold such non-assignable items
         as nominee for Buyer.

9.3      Preferential Rights.

         (A)      Seller agrees that within ten (10) days after the date of this
                  Agreement it will (i) identify all preferential rights to
                  purchase ("Preferential Rights") which would be applicable to
                  the transaction contemplated hereby, and the names and
                  addresses of such parties holding the same and provide a copy
                  of the list of such parties to Buyer, and (ii) request, from
                  the parties so identified (and in accordance with the
                  documents creating such rights), execution of waivers of
                  Preferential Rights.

         (B)      If the holder of a Preferential Right within the time allowed
                  exercises such right, Seller shall tender to such party the
                  required interest in the affected Asset at a price equal to
                  the Allocated Value (reduced appropriately, as determined by
                  mutual agreement of Buyer and Seller, if less than the entire
                  Asset must be tendered), and to the extent that such
                  Preferential Right is exercised and such interest in such
                  Asset is actually sold to the party so exercising such right,
                  such interest in the Asset will be deemed an Excluded Asset
                  and shall be excluded from the transaction contemplated hereby
                  and the Base Purchase Price will be adjusted downward by the
                  Allocated Value.

         (C)      If, on the Closing Date, the holder of a Preferential Right
                  has not indicated whether or not it will exercise such
                  Preferential Right and the time period within which the holder
                  of the Preferential Right must exercise its right has not
                  lapsed, then the Parties shall mutually agree whether to
                  proceed with Closing or delay Closing.

9.4      [INTENTIONALLY DELETED].

9.5      Records and Contracts. Seller shall have the right to make and retain
         copies of the Records and Contracts as Seller may desire prior to the
         delivery of the Records and Contracts to Buyer. Buyer, for a period of
         seven (7) years after the Closing Date, shall make available to Seller
         (at the location of such Records and Contracts in Buyer's organization)
         access to such Records and Contracts as Buyer may have in its
         possession (or to which it may have access) upon written request of
         Seller, during normal business hours; provided, however, that Buyer
         shall not be liable to Seller for the loss of any Records or Contracts
         by reason of clerical error or inadvertent loss or destruction of
         Records or Contracts. Seller, for a period of seven (7) years after the
         Closing Date, shall make available to Buyer (at the location of such
         records in Seller's organization) access to records described in
         Section 1.1(J)(i),(ii)(iii) (the "Excluded Records") as Seller may have
         in its possession (or to which it may have access) upon written request
         of Buyer, during normal business hours; provided, however, that Seller
         shall not be

                                                                              32
<PAGE>

         liable to Buyer for the loss of any Excluded Records by reason of
         clerical error or inadvertent loss or destruction of Excluded Records.
         Notwithstanding the foregoing Buyer may convey the Records associated
         with any property sold to a third party, subject to the purchaser of
         said property assuming the obligations remaining under this Section 9.5
         above with regard to said property.

9.6      Termination of Affiliate Contracts. At Buyer's request, made no later
         than the 90th day after Closing, Seller shall terminate specified
         Seller affiliate contracts or agreements affecting the Assets with any
         of Seller's affiliated entities other than the Helium Processing
         Agreement dated December 1, 1999, however, Seller will not be obligated
         to terminate such contracts before Closing.

9.7      Gas Quality Waiver. From and after the date of this Agreement, CIG
         agrees to waive the oxygen specifications of its FERC gas tariff, as
         amended from time to time ("CIG's Tariff") for gas delivered to CIG by
         Buyer at the Big Canyon compressor station point of receipt for
         transportation on CIG's FERC-jurisdictional transmission system,
         unless: (i) such gas contains more than 2000 parts per million (.200
         percent) by volume of oxygen; or (ii) CIG, in its reasonable discretion
         and judgment, has determined that such gas tendered must conform to the
         quality specifications of CIG's Tariff to (1) maintain prudent and safe
         operation of part or all of CIG's transmission system and storage
         facilities; or (2) ensure that such gas does not adversely affect
         Seller's ability to provide service to others; or (3) ensure that such
         gas will be accepted for delivery by a downstream pipeline or end user.
         Provided however, in the event of any conflict between the foregoing
         provision and the provisions of CIG's FERC gas tariff, such tariff
         shall control.

10.      CERTAIN AGREEMENTS OF BUYER. Buyer agrees and covenants that unless
         Seller shall have consented otherwise in writing, the following
         provisions shall apply:

10.1     [INTENTIONALLY DELETED].

10.2     Plugging Bond. Buyer shall post, prior to Closing, the necessary bonds
         or letters of credit as required by the state in which the Leases are
         located for the plugging of all Wells, and provide Seller with a copy
         of same, and provide proof satisfactory to Seller that the applicable
         state has accepted such bonds or letters of credit as sufficient
         assurance to cover the plugging of all Wells and related matters.
         Further, Buyer shall provide to Seller copies of the approval by any
         applicable regulatory agencies concerning change of operatorship of the
         Wells.

10.3     Seller's Logos. After Closing, Buyer shall promptly cover or cause to
         be covered by decals or new signage any names and marks used by Seller,
         and all variations and derivatives thereof and logos relating thereto,
         from the Assets and shall not thereafter make any use whatsoever of
         such names, marks and logos. Buyer shall complete such work by no later
         than sixty (60) days after Closing.

                                                                              33
<PAGE>

10.4     [INTENTIONALLY DELETED]

10.5     Like-Kind Exchanges. Prior to Closing, Buyer shall cooperate fully, as
         and to the extent reasonably requested by Seller, in connection with
         the transactions contemplated herein to make such modifications as may
         be necessary to qualify such transactions, in whole or in part, as a
         "like-kind" exchange pursuant to Section 1031 of the Code.

10.6     [INTENTIONALLY DELETED]

11.      CONDITIONS PRECEDENT TO OBLIGATIONS OF BUYER. All obligations of Buyer
         under this Agreement are, at Buyer's election, subject to the
         fulfillment, prior to or at the Closing, of each of the following
         conditions:

11.1     No Litigation. At the Closing, no suit, action or other proceeding
         shall be pending before any court or governmental agency which attempts
         to prevent the occurrence of the transactions contemplated by this
         Agreement.

11.2     Representations and Warranties. All representations and warranties of
         Seller contained in this Agreement shall be true in all material
         aspects as of the Closing as if such representations and warranties
         were made as of the Closing Date (except for those representations or
         warranties that are expressly made only as of another specific date,
         which representations and warranties shall be true in all material
         respects as of such other date) and Seller shall have performed and
         satisfied in all material respects all covenants and fulfilled all
         conditions required by this Agreement to be performed and satisfied by
         Seller at or prior to the Closing.

11.3     [INTENTIONALLY DELETED

11.4     Acquisition of Gathering Assets. Buyer and CIG shall have executed a
         definitive agreement on or before 5:00 p.m. April 13, 2002, for the
         purchase by Buyer of CIG's Panhandle Field, Texas gathering system and
         the Gathering Initial Closing occurs contemporaneously with the Closing
         herewith. For purposes of this Agreement the "Gathering Initial
         Closing" means the closing of the transfer to Buyer of the right to
         receive the same economic benefits and the obligation to assume the
         same economic detriments of the ownership of CIG's West Panhandle Field
         gathering system as if Buyer had purchased such gathering system as of
         such date. The Gathering Initial Closing is anticipated to occur July
         1, 2002, and is anticipated to predate the actual transfer of title to
         such gathering system, which cannot occur until after the FERC has
         granted abandonment approval.

11.5     Seller's Receipt of Waiver. That Seller has received the waivers or
         amendments referred to in Section 12.3 below.


                                                                              34
<PAGE>

12.      CONDITIONS PRECEDENT TO THE OBLIGATIONS OF SELLER. All obligations of
         Seller under this Agreement are, at Seller's election, subject to the
         fulfillment, prior to or at the Closing, of each of the following
         conditions:

12.1     No Litigation. At the Closing, no suit, action or other proceeding
         shall be pending before any court or governmental agency which attempts
         to prevent the occurrence of the transactions contemplated by this
         Agreement.

12.2     Representations and Warranties. All representations and warranties of
         Buyer contained in this Agreement shall be true in all material aspects
         as of the Closing, as if such representations and warranties were made
         as of the Closing Date (except for those representations or warranties
         that are expressly made only as of another specific date, which
         representations and warranties shall be true in all material respects
         as of such other date) and Buyer shall have performed and satisfied in
         all material respects all covenants and fulfilled all conditions
         required by this Agreement to be performed and satisfied by Buyer at or
         prior to the Closing.

12.3     Waivers of Restrictions. Except for those Assets located in the Gulf of
         Mexico, the Assets to be sold by the Seller support a financing, and
         the sale of the Assets is subject to certain restrictions (including
         potential mandatory prepayments of such financing) imposed under the
         terms of such financing. The Parties hereby agree that, as a condition
         precedent to the Parties' respective obligations to close the sale of
         the Assets, the Seller shall have obtained effective waivers or
         amendments--in each case on terms acceptable to Seller--of the
         restrictive provisions of such financing relating to sales of the
         Assets. The Seller agrees to use commercially reasonable efforts to
         obtain such waivers or amendments prior to the Effective Time,

12.4     Disposition of Gathering Assets. Buyer and CIG shall have executed a
         definitive agreement on or before 5:00 p.m. on April 13, 2002, for the
         sale by CIG to Buyer of CIG's Panhandle Field, Texas gathering system
         and the Gathering Initial Closing occurs contemporaneously with the
         Closing herewith.

13.      TERMINATION.

13.1     Causes of Termination. This Agreement and the transactions contemplated
         herein may be completely terminated:

                                                                              35
<PAGE>

         (A)      At any time by mutual consent of the Parties.

         (B)      By either Party if the Closing shall not have occurred by
                  September 1, 2002, despite the good faith reasonable efforts
                  of the Parties, and if the Party desiring to terminate is not
                  in breach of this Agreement.

         (C)      [INTENTIONALLY DELETED]

         (D)      By either Party in the event of a Casualty Loss pursuant to
                  Section 15.1(B).

         (E)      By either Party if less than ninety percent (90%) of the Base
                  Purchase Price shall be transferred to Seller on the Closing
                  Date.

         (F)      By Buyer if, on the Closing Date, any of the conditions set
                  forth in Article 11 hereof shall not have been satisfied or
                  waived.

         (G)      By Seller if, on the Closing Date, any of the conditions set
                  forth in Article 12 hereof shall not have been satisfied or
                  waived.

13.2     Effect of Termination. In the event of the termination of this
         Agreement pursuant to the provisions of this Article 13 or elsewhere in
         this Agreement, this Agreement shall become void and have no further
         force and effect and neither Party shall have any further right, duty
         or liability to the other hereunder, except for: (i) the indemnity
         provided for in Section 6.6(B), (ii) any breach of this Agreement prior
         to such termination; and (iii) any other continuing confidentiality
         requirement. Upon termination, Buyer agrees to use commercially
         reasonable efforts to return to Seller, or destroy, all materials,
         documents and copies thereof provided, obtained or discovered in the
         course of any due diligence investigations.

14.      INDEMNIFICATION

14.1     INDEMNIFICATION BY SELLER. UPON AND AFTER CLOSING, SELLER SHALL TO THE
         FULLEST EXTENT PERMITTED BY LAW, RELEASE, DEFEND, INDEMNIFY, AND HOLD
         HARMLESS BUYER, ITS PARENT AND SUBSIDIARY COMPANIES, AND EACH OF THEIR
         RESPECTIVE DIRECTORS, OFFICERS, EMPLOYEES, AGENTS AND OTHER
         REPRESENTATIVES (THE "BUYER GROUP") FROM AND AGAINST THE FOLLOWING:

         (A)      MISREPRESENTATIONS. ALL CLAIMS, DEMANDS, LIABILITIES,
                  JUDGMENTS, LOSSES AND REASONABLE COSTS, EXPENSES AND
                  ATTORNEYS' FEES (INDIVIDUALLY A "LOSS" AND COLLECTIVELY, THE
                  "LOSSES") ARISING FROM THE BREACH BY SELLER OF ANY
                  REPRESENTATION OR WARRANTY SET FORTH IN THIS AGREEMENT TO THE
                  EXTENT THE SAME SURVIVES CLOSING;

         (B)      BREACH OF COVENANTS. ALL LOSSES ARISING FROM THE BREACH BY

                                                                              36
<PAGE>

                  SELLER OF ANY COVENANT SET FORTH IN THIS AGREEMENT TO THE
                  EXTENT THE SAME SURVIVES CLOSING; AND

         (C)      OWNERSHIP AND OPERATION. EXCEPT FOR MATTERS INDEMNIFIED BY
                  BUYER PURSUANT TO SECTION 14.2 BELOW AND IN THE TRANSITION
                  AGREEMENT (WHEN EXECUTED), ALL LOSSES ARISING FROM THE
                  OWNERSHIP AND OPERATION OF THE ASSETS PRIOR TO THE EFFECTIVE
                  TIME DIRECTLY ASSOCIATED WITH THE FOLLOWING MATTERS:

                  (i)      OIL OR GAS WELLS PLUGGED AND ABANDONED ON THE ASSETS
                           BY SELLER OR ANY OF SELLER'S PREDECESSORS IN INTEREST
                           PRIOR TO THE EFECTIVE TIME AND REGARDLESS IF SAID
                           WELLS ARE DESCRIBED ON EXHIBIT 1.1(A)-2; AND

                  (ii)     ALL TAXES FOR ALL PERIODS UP TO CLOSING OTHER THAN
                           TAXES WHICH, IF PAID BY SELLER, WOULD RESULT IN A
                           PURCHASE PRICE ADJUSTMENT IN ITS FAVOR UNDER SECTION
                           2.2(A)(ii);

                  (iii)    (AS TO THE ASSETS LOCATED OR PERTAINING TO KANSAS,
                           OKLAHOMA AND THE GULF OF MEXICO) ALL LOSSES ARISING
                           FROM THE OWNERSHIP AND OPERATION OF THE ASSETS PRIOR
                           TO THE EFFECTIVE TIME, DIRECTLY ASSOCIATED WITH THE
                           FOLLOWING MATTERS:

                           (a)      DAMAGES TO PERSONS OR PROPERTY;

                           (b)      THE VIOLATION BY SELLER OF ANY LAW OR
                                    REGULATION OR THE TERMS OF ANY AGREEMENT
                                    BINDING UPON BUYER;

                           (c)      CLAIMS OF SELLER'S CO-OWNERS, PARTNERS,
                                    JOINT VENTURERS AND OTHER PARTICIPANTS IN
                                    THE WELLS (EXCLUDING BUYER);

                           (d)      TAXES ATTRIBUTABLE TO THE ASSETS OTHER THAN
                                    TAXES DESCRIBED IN SECTION 14.1(C)(ii); AND

                           (e)      THE INCORRECT PAYMENT, NON-PAYMENT OR
                                    MISPAYMENT OF ROYALTIES UNDER THE LEASES.

                           SELLER'S OBLIGATIONS UNDER THIS SUBSECTION
                           14.1(C)(iii) SHALL EXPIRE ON THE SECOND ANNIVERSARY
                           OF THE DATE OF CLOSING.

                                                                              37
<PAGE>

14.2     INDEMNIFICATION BY BUYER. UPON AND AFTER CLOSING, BUYER SHALL TO THE
         FULLEST EXTENT PERMITTED BY LAW, RELEASE, DEFEND, INDEMNIFY, AND HOLD
         HARMLESS THE SELLER GROUP AGAINST THE FOLLOWING:

         (A)      MISREPRESENTATIONS. ALL LOSSES ARISING FROM THE BREACH BY
                  BUYER OF ANY REPRESENTATION OR WARRANTY SET FORTH IN THIS
                  AGREEMENT TO THE EXTENT THE SAME SURVIVES CLOSING;

         (B)      BREACH OF COVENANTS. ALL LOSSES ARISING FROM THE BREACH BY
                  BUYER OF ANY COVENANT SET FORTH IN THIS AGREEMENT TO THE
                  EXTENT THE SAME SURVIVES CLOSING;

         (C)      OWNERSHIP AND OPERATION. EXCEPT FOR MATTERS INDEMNIFIED BY
                  SELLER PURSUANT TO SECTION 14.1 ABOVE, ALL LOSSES ARISING FROM
                  THE OWNERSHIP AND OPERATION OF THE ASSETS FROM AND AFTER THE
                  EFFECTIVE TIME, DIRECTLY ASSOCIATED WITH THE FOLLOWING
                  MATTERS:

                  (i)      DAMAGES TO PERSONS OR PROPERTY;

                  (ii)     THE VIOLATION BY BUYER OF ANY LAW OR REGULATION OR
                           THE TERMS OF ANY AGREEMENT BINDING UPON BUYER;

                  (iii)    CLAIMS OF BUYER'S CO-OWNERS, PARTNERS, JOINT
                           VENTURERS AND OTHER PARTICIPANTS IN THE WELLS
                           (EXCLUDING SELLER);

                  (iv)     TAXES ATTRIBUTABLE TO THE ASSETS OTHER THAN TAXES
                           DESCRIBED IN SECTION 14.1(C)(ii); AND

                  (v)      THE INCORRECT PAYMENT, NON-PAYMENT OR MISPAYMENT OF
                           ROYALTIES UNDER THE LEASES.

         (D)      OPERATION OF THE WEST PANHANDLE FIELD. EXCEPT FOR MATTERS
                  INDEMNIFIED BY SELLER PURSUANT TO SECTION 14.1 ABOVE, ALL
                  LOSSES ARISING FROM THE PHYSICAL OPERATION BY BUYER SINCE
                  JANUARY 1, 1990 OF THE WEST PANHANDLE FIELD DIRECTLY
                  ASSOCIATED WITH DAMAGES TO THIRD PARTIES OR PROPERTY. BUYER'S
                  OBLIGATIONS UNDER THIS SUBSECTION 14.2(D) SHALL EXPIRE ON THE
                  SECOND ANNIVERSARY OF THE CLOSING.

                                                                              38
<PAGE>

14.3     Additional Plugging Obligations. From and after Closing the following
         provisions shall apply;

         (A). In addition to Seller's other obligations under Section 14.1(C)(i)
         under this Agreement, as to wells located on the Assets in Oklahoma and
         Kansas only, Seller shall retain the obligation to properly plug and
         abandon any and all such wells which are not plugged and abandoned by
         Closing and which are not listed on Exhibit 1.1(A)(2) and SHALL DEFEND,
         INDEMNIFY AND HOLDHARMLESS THE BUYER GROUP FROM ALL LOSSES REGARDING
         SAME; AND

         (B) Except as provided in Sections 14.1(C) and 14.3 (A) above,Buyer
         shall perform and assume all liability for the necessary and proper
         plugging and abandonment of all Wells not plugged and abandoned prior
         to Closing AND SHALL DEFEND, INDEMNIFY AND HOLD HARMLESS THE SELLER
         GROUP FROM ALL LOSSES REGARDING SAME.

14.4     Notification. Neither Party shall be obligated to indemnify the other
         for any Loss unless notice regarding same has been sent as provided in
         this Agreement but the obligation to indemnify hereunder shall continue
         beyond any applicable survival period under this Agreement to the
         extent such notice has been given. As soon as reasonably practical
         after obtaining knowledge thereof, the indemnified Party shall notify
         the indemnifying Party of any claim or demand which the indemnified
         Party has determined has given or could give rise to a claim for
         indemnification under this Article 14. Such notice shall specify the
         agreement, representation or warranty with respect to which the claim
         is made, the facts giving rise to the claim and the alleged basis for
         the claim, and the amount (to the extent then determinable) of
         liability for which indemnity is asserted. In the event any action,
         suit or proceeding is brought with respect to which a Party may be
         liable under this Article 14, the defense of the action, suit or
         proceeding (including all settlement negotiations and arbitration,
         trial, appeal, or other proceeding) shall be at the discretion of and
         conducted by the indemnifying Party. If an indemnified Party shall
         settle any such action, suit or proceeding without the written consent
         of the indemnifying Party (which consent shall not be unreasonably
         withheld), the right of the indemnified Party to make any claim against
         the indemnifying Party on account of such settlement shall be deemed
         conclusively denied. An indemnified Party shall have the right to be
         represented by its own counsel at its own expense in any such action,
         suit or proceeding, and if an indemnified Party is named as the
         defendant in any action, suit or proceeding, it shall be entitled to
         have its own counsel and defend such action, suit or proceeding with
         respect to itself at its own expense. Subject to the foregoing
         provisions of this Article 14, neither Party shall, without the other
         Party's written consent, settle, compromise, confess judgment or permit
         judgment by default in any action, suit or proceeding if such action
         would create or attach any liability or obligation to the other Party.
         The Parties agree to make available to each other, and to their
         respective counsel and accountants, all information and documents
         reasonably available to them which relate to any action, suit or
         proceeding, and the Parties agree to render to each other such
         assistance as

                                                                              39
<PAGE>

         they may reasonably require of each other in order to ensure the proper
         and adequate defense of any such action, suit or proceeding.

14.5     LIMITATION ON DAMAGES. The indemnification obligations of Buyer and
         Seller pursuant to this Article 14 shall be limited to actual Losses
         and shall not include incidental, consequential, indirect, punitive or
         exemplary Losses except to the extent the indemnified Party is
         obligated to pay non-affiliated third parties for such Losses.

14.6.    Notwithstanding the foregoing sections in this Article 14, this Article
         14 shall take into account the gain or benefit which either Party would
         have received and/or the loss or burden for which either Party would be
         obligated under the terms of the 'B' Contract Documents up to Effective
         Time as if this Agreement had not been executed, except as otherwise
         expressly provided in this Agreement.

15.      MISCELLANEOUS.

15.1     Casualty Loss.

         (A)      An event of casualty means volcanic eruptions, acts of God,
                  fire, explosion, earthquake, wind storm, flood, drought,
                  condemnation, the exercise of any right of eminent domain,
                  confiscation and seizure (a "Casualty"). A Casualty does not
                  include depletion due to normal production and depreciation or
                  failure of equipment or casing.

         (B)      If, prior to the Closing, a Casualty occurs (or Casualties
                  occur) which results in a reduction in the value of the Assets
                  in excess of ten percent (10%) of the Base Purchase Price (as
                  determined immediately prior to such Casualty Loss) ["Casualty
                  Loss"], Buyer or Seller may elect prior to Closing to
                  terminate this Agreement. If this Agreement is not so
                  terminated, then this Agreement shall remain in full force and
                  effect notwithstanding any such Casualty Loss, and, upon
                  agreement of the Parties, (i) Seller may retain such Asset and
                  such Asset shall be the subject of an adjustment to the Base
                  Purchase Price in the same manner set forth in Section 5.6
                  hereof, or (ii) at the Closing, Seller shall pay to Buyer all
                  sums paid to Seller by reason of such Casualty Loss, (provided
                  however, that the Base Purchase Price shall not be adjusted by
                  reason of such payment except to the extent said payment is
                  less than the value of the damage to the affected Asset, and
                  then the Base Purchase Price shall be reduced only by the
                  difference between the payment and the damage to the affected
                  Asset, and Seller shall at Closing assign, transfer and set
                  over unto Buyer all of the right, title and interest of Seller
                  in and to such Asset and any unpaid awards or other payments
                  arising out of such Casualty Loss.

         (C)      For purposes of determining the diminution in value of an
                  Asset as a result of a Casualty Loss, the Parties shall use
                  the same methodology as applied in determining

                                                                              40
<PAGE>

                  the diminution in value of an Asset as a result of a Title
                  Defect as set forth in Section 5.6.

15.2     Third Party Beneficiaries. There are no third parties intended to
         benefit from this Agreement other than the parties protected or
         indemnified by either Party pursuant to Article 14 and then only to the
         extent provided in said Article 14.

15.3     Competition. Buyer acknowledges that Seller may presently own interests
         or have leads, prospects, information or ideas on properties or
         leaseholds adjacent to, adjoining or in the vicinity of the Assets.
         Seller shall not be prohibited in any way from competing with Buyer or
         pursuing any activity or business opportunity on property not being
         transferred to Buyer pursuant to this Agreement and Buyer shall not be
         prohibited in any way from competing with Seller or pursuing any
         activity or business opportunity on property not being transferred to
         Buyer pursuant to this Agreement.

15.4     Notices. Any notice, request, demand, or consent required or permitted
         to be given hereunder shall be in writing and delivered in person or by
         certified letter, with return receipt requested, or by facsimile
         addressed to the Party for whom intended at the following addresses:

         SELLER:

                  EL PASO GOM INC.
                  9 Greenway Plaza
                  Houston, Texas 77046
                  Attn: Offshore Land Department- Patrick Grammar
                  Tel: (832) 676-5019
                  Fax: (832) 676-1161

                  COLORADO INTERSTATE GAS COMPANY
                  CIG PRODUCTION COMPANY, L.P.
                  2 North Nevada Ave.
                  Colorado Springs, CO 80903
                  Attn:    Greg Gettman.
                  Tel:     (719) 520-4533
                  Fax:     (719) 520-4618

         BUYER:
                  PIONEER NATURAL RESOURCES USA, INC.
                  5205 N. O'Connor Blvd., Suite 1400
                  Irving, Texas 75039-3746
                  Attn: W. T. Howard
                  Tel:  (972) 969-3811
                  Fax:  (972) 969-3533

                                                                              41
<PAGE>

         or at such other address as any of the above shall specify by like
         notice to the other.

15.5     Press Releases and Public Announcements. No Party shall issue any press
         release or make any public announcement relating to the subject matter
         of this Agreement prior to the Closing without the prior written
         approval of the other Party; provided, however, that any Party may make
         any public disclosure it believes in good faith is required by
         applicable law or any listing or trading agreement concerning its or
         its affiliates' publicly-traded securities (in which case the
         disclosing Party shall use all reasonable efforts to advise the other
         Party, and give the other Party an opportunity to comment on the
         proposed disclosure, prior to making the disclosure).

15.6     Personnel.

         As of Closing, per Seller's request, Buyer agrees to offer employment,
         effective at Closing, to that individual named on that separate
         correspondence of even date from Seller to Buyer. The offer shall
         include:

            1. At least the same monthly base salary paid as provided in that
               letter to Buyer dated April 9, 2002 ( and Pioneer may terminate
               the said employee for cause, but may not decrease such salary
               prior the first anniversary of the Closing); and

            2. Recognition of the said employee's years of actual service with
               Seller and its affiliates for purposes of vacation and sick leave
               entitlement under the terms of applicable Buyer policies and
               plans; and

            3. Recognition of the said employee's years of actual service with
               Seller and its affiliates for purposes of vesting in any Buyer
               pension benefit plan (as defined in the Employee Retirement
               Income Security Act of 1974 (ERISA), as amended; and

            4. Recognition of the said employee's years of actual service with
               Seller and its affiliates affiliate for purposes of calculating
               benefits under any Buyer severance plan under which the said
               employee may become eligible for benefits.

            5. Buyer may condition such offers on said employee's satisfaction
               of Buyer's pre-employment drug testing and background check
               requirements.

         Without Seller's prior written consent, for a period ending six (6)
         months from the Closing, Buyer will not directly or indirectly solicit
         for employment any person who is now employed by Seller or its
         affiliates involved in the exploration and production business in an
         executive, management, technical or professional position or otherwise
         considered by Seller to be a key employee. Without Buyer's prior
         written consent, for a period ending six (6) months from the Closing,
         Seller will not directly or indirectly solicit for employment any
         person who is now employed by Buyer or its affiliates involved in the
         exploration and production business in an executive, management,
         technical or professional position or otherwise considered by Buyer to
         be a key employee.

15.7     Compliance with Express Negligence Test. THE PARTIES AGREE THAT THE
         INDEMNIFICATION

<PAGE>

         OBLIGATIONS OF THE INDEMNIFYING PARTY SHALL BE WITHOUT REGARD TO THE
         NEGLIGENCE OR STRICT LIABILITY OF THE INDEMNIFIED PERSON(S), WHETHER
         THE NEGLIGENCE OR STRICT LIABILITY IS ACTIVE, PASSIVE, JOINT,
         CONCURRENT OR SOLE.

15.8     Governing Law. This Agreement is governed by and must be construed
         according to the laws of the State of Texas, excluding any
         conflicts-of-law rule or principle that might apply the law of another
         jurisdiction. All disputes related to this Agreement shall be submitted
         to the jurisdiction of the courts of the State of Texas and venue shall
         be in the civil district courts of Harris County, Texas.

15.9     Exhibits. The Exhibits attached to this Agreement are incorporated into
         and made a part of this Agreement.

15.10    Fees, Expenses, Taxes and Recording.

         (A)      Each Party shall be solely responsible for all costs and
                  expenses incurred by it in connection with this transaction
                  (including, but not limited to fees and expenses of its
                  counsel and accountants) and shall not be entitled to any
                  reimbursements from the other Party, except as otherwise
                  provided in this Agreement.

         (B)      Buyer shall file all necessary tax returns and other
                  documentation with respect to all transfer, documentary,
                  sales, use, stamp, registration and other similar taxes and
                  fees, and, if required by applicable law, Seller shall join in
                  the execution of any such tax returns and other documentation.
                  Notwithstanding anything set forth in this Agreement to the
                  contrary, Buyer shall pay any transfer, documentary, sales,
                  use, stamp, registration and other similar taxes and fees
                  incurred in connection with this Agreement and the
                  transactions contemplated hereby.

         (C)      Buyer shall, at its own cost, immediately record all
                  instruments of conveyance and sale in the appropriate office
                  of the state and county in which the lands covered by such
                  instrument are located. Buyer shall immediately file for and
                  obtain the necessary approval of all federal, Indian, tribal
                  or state government agencies to the assignment of the Assets.
                  The assignment of any state, federal or Indian tribal oil and
                  gas leases shall be filed in the appropriate governmental
                  offices on a form required and in compliance with the
                  applicable rules of the applicable government agencies. Buyer
                  shall supply Seller with a true and accurate photocopy
                  reflecting the recording information of all the recorded and
                  filed assignments within a reasonable period of time after
                  their recording and filing.

15.11    Assignment/Buyer's Designee. This Agreement or any part hereof may not
         be assigned by either Party without the prior written consent of the
         other Party; provided, however, upon notice to the other Party, either
         Party shall have the right to assign all or part of its rights (but
         none of its obligations) under this Agreement in order to qualify
         transfer of the Assets as a "like-kind" exchange for federal tax
         purposes. Subject to the foregoing, this Agreement is binding upon the
         Parties hereto and their respective successors and assigns.

                                                                              43
<PAGE>

         The conveyance of any of the Assets at Closing to a designee of Buyer
         shall not relieve Pioneer Natural Resources USA, Inc., of any of its
         obligations under this Agreement.

15.12    Entire Agreement. This Agreement constitutes the entire agreement
         reached by the Parties with respect to the subject matter hereof,
         superseding all prior negotiations, discussions, agreements and
         understandings, whether oral or written, relating to such subject
         matter, except that the Confidentiality Agreement dated April 1, 2002,
         between the Parties shall remain in full force and effect in accordance
         with its terms through and until the Closing.

15.13    Severability. In the event that any one or more covenants, clauses or
         provisions of this Agreement shall be held invalid or illegal, such
         invalidity or unenforceability shall not affect any other provisions of
         this Agreement.

15.14    Captions. The captions in this Agreement are for convenience only and
         shall not be considered a part of or affect the construction or
         interpretation of any provision of this Agreement.

15.15    Survival. The covenants of Buyer and Seller contained in this Agreement
         terminate at Closing with the exception of those Articles and Sections
         contained in Exhibit 15.15 which shall survive Closing.





                            -SIGNATURE PAGE FOLLOWS-


                                                                              44
<PAGE>

Executed as of the day and year first above written.

                                     SELLER:

                                     COLORADO INTERSTATE GAS COMPANY


                                     By:   /s/ JOHN W. SOMERHALDER, II
                                         --------------------------------



                                     CIG PRODUCTION COMPANY, L.P.
                                     By: CIG Resources Company,
                                           General Partner


                                     By:    /s/ JOHN W. SOMERHALDER, II
                                         --------------------------------



                                     EL PASO PRODUCTION GOM INC.

                                      By:   /s/ GREGORY W. HUTSON
                                          -------------------------------
                                              Name and Title



                                     BUYER:

                                     PIONEER NATURAL RESOURCES USA, INC.



                                     By:    /s/ MARK L. WITHROW
                                         --------------------------------
                                     Name:      Mark L. Withrow
                                     Title:     Executive Vice President




                                                                              45
<PAGE>
                                    EXHIBIT A
                             'B' CONTRACT DOCUMENTS

1.  Agreement dated January 2, 1928, as amended, between CIG's predecessor in
    interest and Buyer's predecessor in interest.

2.  Westpan Deed dated December 26 1951, as amended, from CIG's predecessor in
    interest to Westpan's predecessor in interest.

3.  Gathering Agreement dated May 29, 1987, as amended, between CIG and Buyer's
    predecessor in interest.

4.  Operating Agreement dated January 8, 1988, as amended, between Seller and
    Buyer's predecessor in interest.

5.  'B' Contract Production Allocation Agreement dated January 1, 1991, as
    amended, between Buyer and CIG.

6.  1996 Fain Gas Processing Agreement dated June 1, 1996, as amended, between
    Seller, Buyer's predecessor in interest and Westpan's predecessor in
    interest.

7.  1996 Agreement dated June 1, 1996, as amended, between Seller and Westpan's
    predecessor in interest.

8.  Gathering System Operating & Maintenance Agreement dated May 1, 2001,
    between CIG and Buyer.

9.  2001 Gathering Agreement dated February 1, 2001, between CIG and Buyer.

10. Various letter agreements, correspondence and other material involving Items
    #1 through #9 above entered or exchanged between or among Buyer, Seller
    and/or their respective predecessors in interest prior to the date of this
    Agreement.

Notwithstanding anything else to the contrary in this Purchase and Sale
Agreement, items 3, 8, and 9 above, and the rights hereunder, are to be conveyed
pursuant to the Gathering Assets Purchase and Sale Agreement anticipated to be
executed.

                                       1
<PAGE>
                                EXHIBIT 1.1(A)-1
                                     LEASES




                                       1
<PAGE>
                                EXHIBIT 1.1(A)-2
                                      WELLS





                                       1

<PAGE>
                              EXHIBIT 1.1 (A)(iii)
                                    EASEMENTS

                                      NONE







                                       2
<PAGE>
                                   EXHIBIT 1.2
                                 EXCLUDED ASSETS

1.  All facilities and related property of any kind comprising CIG's
    FERC-jurisdictional transmission system, including, without limitation:

    o   the Fourway compressor station facilities and associated real property
        (Sections 49 & 50, Block 6T, T&NO Survey, Moore County Texas)

    o   the Big Canyon compressor station facilities and associated real
        property (Section 10, Block 3, G&M Survey, Potter County, Texas)

    o   the Sanford Station facilities and associated real property (Section 82,
        Block 46, H&TC Survey, Hutchinson County, Texas

    o   CIG's metering, pipelines and other equipment at the outlet of the Fain
        processing plant, each as identified on Attachment "A" to this Exhibit
        1.2. (Section 10, Block 3, G&M Survey, Potter County, Texas)

2.  All gas gathering facilities and related real property, including the
    facilities, real property comprising CIG's Panhandle Field gathering system
    and Residue Fuel Pipeline.

3.  Gas Gathering Agreements between CIG and:

    o   Mckee d/b/a Brandy

    o   Bird Creek Resources

    o   Asher Resources

    o   CIG Merchant Company

    o   CIGPC

    o   JM Huber

    o   McClelland

    o   LeeJan Oil

    o   Sulliko

    o   Helo

4.  Lease Agreement between CIG and Buyer dated May 1, 2001. All buildings and
    other facilities owned by Seller and located at the Bivins Station area
    which buildings and facilities are not covered by such Lease Agreement,
    including water for such facilities. (Section 33, Block PMC, EL&RR Survey,
    Potter County, Texas)

                                       3
<PAGE>
5.  Communication towers and associated radio equipment attached as schedule A
    and frequencies (KKY91, KJT43, KKY92, KKY93, WNTP463, WNTQ971, WNTP464,
    WPQS402, WPQB627, KKA661)owned by Seller. Seller will retain an easement at
    Bivins and Fritch to access these facilities.

6.  Seller's accounting records to the extent related to periods prior to 1998,
    except to the extent such records are relevant to a claim or dispute with a
    third party.

7.  Any imbalance (both asset and liability) between CIG and CIGPC, including
    any rights or obligations under an Operational Balancing Agreement between
    CIG and CIGPC.

8.  All aspects of the regulatory treatment by the FERC of the Assets subject to
    the jurisdiction of the FERC, including without limitation, rate treatment
    of such Assets and associated property.

                                       4
<PAGE>
Attachment "A" to Exhibit 1.2

Transmission pipelines:
F-1266
F-1267
3A
147A
147B
148A
193A
194A

                                       5
<PAGE>
                                EXHIBIT 2.2(A)(v)


                                EXHIBIT 2.2(A)(v)
                         SPLIT INTEREST WELL IMBALANCES
                             AS OF FEBRUARY 28, 2002


Well Name                                          Imbalance Volume (MMBtu)
---------                                          ------------------------
Greenwood C-1                                             +111
Barrick #1                                                -352
Entrinkin #2                                              -117
Gens #1                                                   -3,717
Hurst #2                                                  +1,013
Minns #1                                                  -2,187
Phillips B-1                                              +5,975
Smith #1                                                  +294

                  NET IMBALANCE                           +1,024

(+) Imbalances due CIG Production Company
(-) Imbalances due other working interest owners

                                       6
<PAGE>
                                   EXHIBIT 2.3
                        ALLOCATION OF BASE PURCHASE PRICE






                                       1
<PAGE>

                                 EXHIBIT 3.2 (A)
                               FORM OF ASSIGNMENT


STATE OF TEXAS                    ss.
                                  ss.
COUNTY OF ________________        ss.





                           ASSIGNMENT AND BILL OF SALE

        [TO BE CONFORMED TO THE TERMS OF THE PURCHASE AND SALE AGREEMENT]

      __________________, a ___________ corporation, (herein called "Assignor"),
whose address is _____________________, for Ten Dollars ($10.00) and other good
and valuable consideration, the receipt and sufficiency of which are hereby
acknowledged, does hereby GRANT, BARGAIN, SELL, CONVEY, ASSIGN, TRANSFER, SET
OVER, and DELIVER unto ________________, a __________ corporation (herein called
"Assignee"), whose address is ________________________, all of Assignor's right,
title and interest in and to the following (collectively called the "Assets"):

      (A) COPY FROM PSA AND EDIT APPROPRIATELY

      The Assets shall not include, and there is excepted, reserved and excluded
from this Assignment those items listed in Exhibit 1.2 (the "Excluded Assets").

      TO HAVE AND TO HOLD the Assets unto Assignee, its successors and assigns,
forever.

      This Assignment is made and accepted expressly subject to the following
terms and conditions:

1.    THIS ASSIGNMENT IS MADE WITHOUT WARRANTY OF ANY KIND, EXPRESS, IMPLIED OR
      STATUTORY, EXCEPT THAT ASSIGNOR WARRANTS AND FOREVER WILL DEFEND THE
      ASSETS CONVEYED UNTO ASSIGNEE FROM AND AGAINST ALL PERSONS CLAIMING THE
      ASSETS OR ANY PART THEREOF BY, THROUGH OR UNDER ASSIGNOR, BUT NOT
      OTHERWISE.

2.    ASSIGNOR EXPRESSLY DISCLAIMS AND NEGATES ANY WARRANTY AS TO THE CONDITION
      OF ANY PERSONAL PROPERTY, EQUIPMENT, FIXTURES AND ITEMS OF MOVABLE
      PROPERTY COMPRISING ANY PART OF THE ASSETS, IT BEING EXPRESSLY UNDERSTOOD
      THAT SAID PERSONAL PROPERTY, FIXTURES, EQUIPMENT AND ITEMS ARE BEING
      CONVEYED TO ASSIGNEE "AS IS" AND

                                       1
<PAGE>
      "WHERE IS" AND WITHOUT WARRANTY OF MERCHANTABILITY, CONDITION OR FITNESS
      FOR A PARTICULAR PURPOSE, EITHER EXPRESS OR IMPLIED.

3.    This Assignment is made subject to the Purchase and Sale Agreement between
      Assignor and Assignee dated as of ________, 2002 (the "Purchase and Sale
      Agreement"). If there is any conflict between the terms of this Assignment
      (other than the terms of Assignor's warranty set forth in paragraph 1
      above) and the terms of the Purchase and Sale Agreement, the Purchase and
      Sale Agreement shall control in all respects and shall not merge into the
      terms of this Assignment.

4.    To the extent permitted by law, Assignee shall be subrogated to Assignor's
      rights in and to representations, warranties and covenants given with
      respect to the Assets, Assignor hereby grants and transfers to Assignee,
      its successors and assigns, to the extent so transferable and permitted by
      law, the benefit of and the right to enforce the covenants,
      representations and warranties, if any, which Assignor is entitled to
      enforce with respect to the Assets.

5.    Assignor shall execute and deliver to Assignee, from time to time, such
      other and additional instruments, notices, division orders, transfer
      orders and other documents, and do all such other and further acts and
      things as may be necessary to more fully and effectively grant, convey and
      assign to Assignee the Assets and to satisfy the intent of the Purchase
      and Sale Agreement.

6.    Unless provided otherwise, all recording references in the Exhibits hereto
      are to the official real property records of the county in which the
      Assets are located.

7.    This Assignment binds and inures to the benefit of Assignor and Assignee
      and their respective successors and assigns.

8.    This Assignment may be executed in any number of counterparts, and each
      such counterpart shall be deemed to be an original and all of which
      together shall constitute one and the same instrument.

      This Assignment is effective as of _____ a.m. (Central Time) on
___________, 2002 (the "Effective Time").

                            -SIGNATURE PAGE FOLLOWS-


                                       2
<PAGE>
      IN WITNESS WHEREOF, Assignor and Assignee have executed this Assignment on
the date set forth in their respective acknowledgments below, but effective for
all purposes as of the Effective Time.

                                   ASSIGNOR:

                                   By: _________________________________

                                   Name: _______________________________

                                   Title: ______________________________




                                   ASSIGNEE:

                                   By: _________________________________

                                   Name: _______________________________

                                   Title: ______________________________




                                       3
<PAGE>
STATE OF TEXAS               ss.
                             ss.
COUNTY OF HARRIS             ss.

Before me, the undersigned authority, a Notary Public in and for the County of
Harris, State of Texas, personally appeared ______________________, to me known
to be the person who executed the within and foregoing instrument as the
______________ of _________________, and acknowledged to me that he executed the
same as the free and voluntary act and deed of such corporation for the uses and
purposes therein set forth.

GIVE UNDER MY OFFICIAL SEAL, this ___ day of __________, 2002.

My Commission Expires:                      ____________________________
                                            Notary Public in and for
                                            Harris County, Texas



STATE OF TEXAS               ss.
                             ss.
COUNTY OF HARRIS             ss.

Before me, the undersigned authority, a Notary Public in and for the County of
Harris, State of Texas, personally appeared ______________________, to me known
to be the person who executed the within and foregoing instrument as the
______________ of ______________________, and acknowledged to me that he
executed the same as the free and voluntary act and deed of such corporation for
the uses and purposes therein set forth.

GIVE UNDER MY OFFICIAL SEAL, this ___ day of ___________, 2002.

My Commission Expires:                      ____________________________
                                            Notary Public in and for
                                            Harris County, Texas


                                       4
<PAGE>
                                 EXHIBIT 3.2(B)
                      CERTIFICATIONS OF NON-FOREIGN STATUS

      Section 1445 of the Internal Revenue Code provides that a transferee
(buyer) of a U.S. real property interest must withhold tax if the transferor
(seller) is a foreign person. To inform the transferee (buyer) that withholding
of tax is not required upon my disposition of a U.S. real property interest, the
undersigned hereby certifies under penalties of perjury the following on behalf
of Colorado Interstate Gas Company:

1.    Colorado Interstate Gas Company is not a foreign corporation, foreign
      partnership, foreign trust, or foreign estate (as those terms are defined
      in the Internal Revenue Code and Income Tax Regulations) nor a nonresident
      alien for U.S. income tax purposes;


      Colorado Interstate Gas Company's U.S. employer identification number is
      TIN: _______________________ ; and

      Colorado Interstate Gas Company's office address is P.O. Box 1087,
      Colorado Springs, CO 80944.

2.    Colorado Interstate Gas Company understands that this Certificate may be
      disclosed to the Internal Revenue Service by the transferee and that any
      false statement contained herein could be punished by fine, imprisonment,
      or both.

3.    Under penalties of perjury I declare that I have examined this
      Certification and to the best of my knowledge and belief it is true,
      correct, and complete, and I further declare that I have authority to sign
      this Document on behalf of Colorado Interstate Gas Company.


Date: _________________

                                            COLORADO INTERSTATE GAS COMPANY


                                            By:_________________________________
                                                     William H. Healy, Jr.
                                                     Vice President



                                       1
<PAGE>
STATE OF COLORADO                 )
                                  )
COUNTY OF EL PASO                 )

      Before me, a Notary Public in and for said County and State, on this
_____day of _________________, 2002, personally appeared William H. Healy, Jr.,
on behalf of Colorado Interstate Gas Company, to me known to be the identical
person who subscribed the name of the maker thereof to the foregoing instrument
as its Vice President, and acknowledged to me that he executed the same as his
free and voluntary act and deed and as the free and voluntary act and deed of
such corporation for the uses and purposes therein set forth.

      GIVEN UNDER MY HAND AND SEAL OF OFFICE this the ___ day of ______________,
2002.


(SEAL)                                      __________________________________
                                                 Notary Public in and for
My Commission Expires                            El Paso County, Colorado

______________________                      __________________________________
                                                   (Type or Print Name)




                                       2
<PAGE>
                       CERTIFICATION OF NON-FOREIGN STATUS

      Section 1445 of the Internal Revenue Code provides that a transferee
(buyer) of a U.S. real property interest must withhold tax if the transferor
(seller) is a foreign person. To inform the transferee (buyer) that withholding
of tax is not required upon my disposition of a U.S. real property interest, the
undersigned hereby certifies under penalties of perjury the following on behalf
of CIG Production Company, L.P.:

1.    CIG Production Company, L.P. is not a foreign corporation, foreign
      partnership, foreign trust, or foreign estate (as those terms are defined
      in the Internal Revenue Code and Income Tax Regulations) nor a nonresident
      alien for U.S. income tax purposes;


      CIG Production Company, L.P.'s U.S. employer identification number is TIN:
      _______________________ ; and

      CIG Production Company, L.P.'s office address is 2 North Nevada Ave.,
      Colorado Springs, CO 80903.

2.    CIG Production Company, L.P. understands that this Certificate may be
      disclosed to the Internal Revenue Service by the transferee and that any
      false statement contained herein could be punished by fine, imprisonment,
      or both.

3.    Under penalties of perjury I declare that I have examined this
      Certification and to the best of my knowledge and belief it is true,
      correct, and complete, and I further declare that I have authority to sign
      this Document on behalf of CIG Production Company, L.P..


Date: _________________

                                            CIG PRODUCTION COMPANY, L.P.
                                            By: CIG Resources Company,
                                                  General Partner

                                            By:_________________________________
                                                     William H. Healy, Jr.
                                                     Vice President





                                       3
<PAGE>
STATE OF COLORADO            )
                             )
COUNTY OF EL PASO            )

      Before me, a Notary Public in and for said County and State, on this
_____day of _________________, 2002, personally appeared William H. Healy, Jr.,
on behalf of CIG Resources Company, general partner of CIG Production Company,
L.P., to me known to be the identical person who subscribed the name of the
maker thereof to the foregoing instrument as its Vice President, and
acknowledged to me that he executed the same as his free and voluntary act and
deed and as the free and voluntary act and deed of such corporation for the uses
and purposes therein set forth.

      GIVEN UNDER MY HAND AND SEAL OF OFFICE this the ___ day of ______________,
2002.


(SEAL)                                      __________________________________
                                                 Notary Public in and for
My Commission Expires                            El Paso County, Colorado

______________________                      __________________________________
                                                   (Type or Print Name)





                                       4
<PAGE>
                      CERTIFICATIONS OF NON-FOREIGN STATUS

      Section 1445 of the Internal Revenue Code provides that a transferee
(buyer) of a U.S. real property interest must withhold tax if the transferor
(seller) is a foreign person. To inform the transferee (buyer) that withholding
of tax is not required upon my disposition of a U.S. real property interest, the
undersigned hereby certifies under penalties of perjury the following on behalf
of El Paso Production GOM Inc.:

      1.    El Paso Production GOM Inc.is not a foreign corporation, foreign
            partnership, foreign trust, or foreign estate (as those terms are
            defined in the Internal Revenue Code and Income Tax Regulations) nor
            a nonresident alien for U.S. income tax purposes;

            El Paso Production GOM Inc.'s U.S. employer identification number is
            TIN; and

            El Paso Production GOM Inc.'s office address is P.O. Box 1087,
            Colorado Springs, CO 80944.

      2.    El Paso Production GOM Inc. understands that this Certificate may be
            disclosed to the Internal Revenue Service by the transferee and that
            any false statement contained herein could be punished by fine,
            imprisonment, or both.

      3.    Under penalties of perjury I declare that I have examined this
            Certification and to the best of my knowledge and belief it is true,
            correct, and complete, and I further declare that I have authority
            to sign this Document on behalf of El Paso Production GOM Inc.:



Date: _________________

                                           El Paso Production GOM Inc.:


                                           By:_________________________________



STATE OF COLORADO              )
                               )
COUNTY OF EL PASO              )

      Before me, a Notary Public in and for said County and State, on this
_____day of _________________, 2002, personally appeared on behalf of El Paso
Production GOM Inc.: to me known to be the identical person who subscribed the
name of the maker thereof to the foregoing instrument as its Vice President, and
acknowledged to me that he executed the same as his free and voluntary act and
deed and as the free and voluntary act and deed of such corporation for the uses
and purposes therein set forth.


                                       1
<PAGE>
      GIVEN UNDER MY HAND AND SEAL OF OFFICE this the ___ day of ______________,
2002.


(SEAL)                                      __________________________________
                                                 Notary Public in and for
My Commission Expires                            El Paso County, Colorado

______________________                      __________________________________
                                                   (Type or Print Name)



                                       2
<PAGE>
                                 EXHIBIT 3.2 (H)
                              TRANSITION AGREEMENT


                              TRANSITION AGREEMENT


      THIS TRANSITION AGREEMENT ("Agreement") is entered into the ___ day of   ,
2002, by and between PIONEER NATURAL RESOURCES USA, INC.("Pioneer"), and CIG
PRODUCTION COMPANY, L.P. and Colorado Interstate Gas Company ( collectively
"CIG").

      WHEREAS, on the   day of      , 2002, but effective as of July 1, 2002 CIG
executed and delivered to Pioneer an Assignment and Bill of Sale covering
certain oil and gas properties and related interests described on Exhibit "    "
attached hereto (the "Assets") pursuant to that certain Purchase and Sale
Agreement dated April   , 2002, between CIG, et al. and Pioneer (the "Purchase
and Sale Agreement"); and

      WHEREAS, Pioneer currently operates the Assets located in Texas and CIG
otherwise has provided administrative services and accounts for such Subject
Assets; and

      WHEREAS, the parties hereto desire that CIG continue certain
administrative services for the Subject Assets for a limited period of time in
accordance with the terms of this Agreement.

      NOW, THEREFORE, based upon the mutual covenants and considerations
contained herein, the parties agree as follows:

1.    SCOPE OF SERVICES: Pioneer will physically operate the Assets. Effective
      as of the date of this Agreement, CIG shall endeavor in good faith to
      continue, from and after the Closing under the Purchase and Sale Agreement
      through the production month of August, 2002 the accounting (revenue and
      production/regulatory) and administrative land services (royalty, delay
      rental, shut-in payments and other payments) for the Assets, in general
      conformity to its recent past practices with regard to the Assets. Such
      services shall be performed by CIG after reasonable consultation with
      Pioneer under the terms of this Agreement are limited to the following:

      (a)   To maintain such personnel as may be reasonably necessary to perform
            the services provided under this Agreement;

      (b)   Administer the contracts, books, records and accounts associated
            with the ownership and operation of the Assets;


                                       3
<PAGE>
      (c)   Purchase supplies and materials associated with the administration
            of the Assets as provided in (b) above; provided, however, CIG shall
            not, without the prior written consent of Pioneer, purchase any of
            the above if such purchase is in excess of $1,000 for any single
            item, except in cases reasonably believed by CIG to constitute an
            emergency.

      (d)   Contract for services associated with the administration of the
            Assets provided herein; provided however, CIG shall not, without the
            prior written consent of Pioneer, enter into a service contract
            which would result in a charge in excess of $5,000 except in cases
            reasonably believed by CIG to constitute an emergency;

      (e)   Pay on behalf of Pioneer lease rentals, shut-in royalties, minimum
            royalties, payments in lieu of production, royalties, overriding
            royalties, including all minimum pay balances, production payments,
            net profit payments and similar burdens;

      (f)   Pay out the lease settlements and other liquidated monetary
            obligations that are associated with the accounting and
            administrative land functions and marketing services of the Subject
            Assets;

      (g)   If requested by Pioneer, provide marketing, (as to the Assets
            located in Oklahoma and Kansas only) necessary to sell Pioneer's
            share of the products produced from said Assets;

      (h)   File severance tax returns/reports, regulatory reports and
            responses, and process and remit severance tax amounts to state or
            other governmental authorities, as appropriate.

      (i)   Collect receivables and distribute revenue with regard to the
            Assets;

      (j)   Release any minimum suspense funds as requested by Pioneer;

      (k)   Provide assistance, as reasonably requested by Pioneer, in
            familiarizing Pioneer's personnel (including contract personnel)
            with the administration or operation of said Assets.

2.    LIMITATION ON SERVICES: Notwithstanding anything contained in Section 1 to
      the contrary, CIG shall not have the obligation to provide services under
      the terms of this Agreement to perform any of the duties of Pioneer
      contained in Section 3 below

3.    DUTIES OF Pioneer: At all times which this Agreement is in effect, Pioneer
      agrees:

      (a)   To market all production of oil, gas or other substances from the
            Assets not marketed by CIG, and receive and collect all proceeds
            therefrom;

      (b)   To pay all royalties and other payments with regard to the Assets
            which are not paid by CIG;

      (c)   To pay CIG, upon receipt of CIG's invoice, the sum $38,500 per month
            for its services under this Agreement. In addition, Pioneer shall
            reimburse CIG for the costs allowed to be incurred on Pioneer's
            behalf under this Agreement within thirty (30) days after CIG
            invoice;

                                       4
<PAGE>
      (d)   To perform all accounting functions associated with the ownership
            and/or operator of the Assets not provided by CIG.

4.    TERMINATION AND TURNOVER DATE: This Agreement shall commence on the date
      first referenced above and shall, unless earlier terminated by Pioneer on
      thirty (30) days advance written notice terminate with August as to the
      Assets at 5:00 p.m. on September 30, 2002 (the "Termination Date").

5.    INDEMNIFICATION AND RELEASE: CIG AND ITS OFFICERS, DIRECTORS, AGENTS AND
      EMPLOYEES, ("CIG GROUP") SHALL NOT BE LIABLE FOR ANY CLAIMS, DEMANDS,
      SUITS, CAUSES OF ACTION, LOSSES, DAMAGES, LIABILITIES AND COSTS (INCLUDING
      ATTORNEYS' FEES AND COSTS OF LITIGATION) ("CLAIMS") ARISING OUT OF OR
      RESULTING FROM THIS AGREEMENT OR THE SERVICES PROVIDED BY OR ON BEHALF OF
      THE CIG GROUP UNDER THE TERMS OF THIS AGREEMENT. PIONEER RELEASES THE CIG
      GROUP FROM AND SHALL FULLY PROTECT, INDEMNIFY AND DEFEND THE CIG GROUP AND
      HOLD EACH OF THEM HARMLESS FROM AND AGAINST ANY AND ALL CLAIMS ARISING OUT
      OF OR RESULTING FROM THIS AGREEMENT OR THE SERVICES PROVIDED BY THE CIG
      GROUP UNDER THE TERMS OF THIS AGREEMENT AS WELL AS FOR THE CLAIMS,
      SERVICES OR ACTIONS OF PERSONS MADE AVAILABLE BY PIONEER PURSUANT TO THIS
      AGREEMENT. THE INDEMNITIES AND RELEASE PROVIDED IN THIS AGREEMENT SHALL
      SURVIVE TERMINATION OF THIS AGREEMENT AND SHALL APPLY TO ALL CLAIMS
      SUBJECT TO INDEMNITY AND/OR RELEASE HEREUNDER, INCLUDING THOSE BASED ON
      NEGLIGENCE OF ANY NATURE, INCLUDING SOLE NEGLIGENCE, SIMPLE NEGLIGENCE,
      CONCURRENT NEGLIGENCE, ACTIVE NEGLIGENCE, PASSIVE NEGLIGENCE, STRICT
      LIABILITY OR FAULT OF CIG.

6.    EXCUSED PERFORMANCE: CIG shall be relieved of responsibility to perform
      any services under this Agreement upon any breach of this Agreement by
      Pioneer and CIG shall thereafter be excused from its obligation to perform
      such services.

7.    ASSIGNABILITY: The rights, duties and privileges under this Agreement
      shall not be assigned by the parties hereto without the prior written
      consent of the non-assigning party and any purported assignment without
      such consent shall be void, provided however, CIG shall be entitled to
      engage contract personnel to perform services contemplated under this
      Agreement.

8.    GOVERNING LAW: This Agreement shall be governed by and construed under the
      laws of the State of Texas, excluding any conflict of law rules which may
      require the application of laws of another jurisdiction.

9.    NOTICES: All notices, requests and other communications shall be provided
      in accordance with the terms of the Purchase and Sale Agreement.

10.   SEVERABILITY. If a court of competent jurisdiction finds any clause or
      provision of this Agreement to be void, invalid, or otherwise
      unenforceable, the other clauses and provisions shall remain in full force
      and effect and the clauses and provisions which are determined to be void,

                                       5
<PAGE>
      invalid or unenforceable shall be limited so that they shall remain in
      effect to the full extent permissible by law.

11.   NO MODIFICATION. This Agreement is intended to be in addition to and
      subordinate to and not to modify the Purchase and Sale Agreement, which
      Purchase and Sale Agreement remains in full force and effect in accordance
      with its terms.


      IN WITNESS WHEREOF, the parties agree to the foregoing on the day and year
first set forth above.


                                    PIONEER NATURAL RESOURCES USA, INC.

                                    By:   ___________________________________

                                    Name: ___________________________________

                                    Title:___________________________________


                                    COLORADO INTERSTATE GAS COMPANY

                                    By:   ___________________________________

                                    Name: ___________________________________

                                    Title:___________________________________


                                    CIG PRODUCTION COMPANY, LP

                                    By:   ___________________________________

                                    Name: ___________________________________

                                    Title:___________________________________



                                       6
<PAGE>
                                 EXHIBIT 5.3(B)
              GAS PURCHASE, SALES, PROCESSING AND OTHER AGREEMENTS


1.    Gas Purchase Agreement dated January 1, 1997, between CIGPC and CIG
      Merchant Company.

      a.    Amendment dated May 1, 2001, between the parties.

      b.    Partial Assignment dated May 1, 2001, from CIG Merchant Company to
            CIG Field Services Company.

2.    Gas Purchase Agreements between:

      a.    The Merchant Division of CIG, and Kuehne Oil Company, Inc., dated
            May 3, 1994, for Panhandle Field: Moore, Carson & Potter Counties,
            Texas, assigned by The Merchant Division of CIG to CIG Merchant
            Company effective July 1, 1998.

            i.    Settlement Agreement dated May 3, 1994, between CIG and Kuehne
                  Oil Company.

            ii.   Stipulation, Agreement, and Quitclaim Deed, dated May 3, 1994,
                  between CIG and Kuehne Oil Company.

            iii.  Letter Agreement, dated November 10, 1995, between CIG and MJM
                  Oil & Gas Company (successor in interest to some or all of the
                  interest of Kuehne Oil Company subject to the Settlement
                  Agreement dated May 3, 1994).

      b.    The Merchant Division of CIG, and Kestrel Resources, Inc, Red Cave
            Limited Liability Company, Empiric Energy Inc., Richmond Petroleum,
            Inc., and McAndrew Management, Inc., dated August 11, 1995, assigned
            by The Merchant Division of CIG to CIG Merchant Company on July 1,
            1998.

            i.    Stipulation, Agreement, and Quitclaim Deed, dated August 18,
                  1995, among CIG, CIGPC and Kestrel Resources Inc., Red Cave
                  Limited Liability Company, Empiric Energy Inc., Richmond
                  Petroleum Inc.

3.    Helium Processing Agreement dated December 1, 1999, between CIGPC and
      Keyes Helium Company, LLC.

4.    Service Agreements (casinghead gas) between CIG and:

      a.    Beren Corporation, and Adolph Beren, Harry H. Beren, and Israel
            Henry Beren, co-partners doing business as Okmar Oil Company, dated
            December 1, 1987.

                                       7
<PAGE>
      b.    Coastal Oil & Gas Corporation, dated November 1, 1986 and Letter
            Agreement dated March 3, 1987, subsequently assigned by CO&GA to
            Jetta Production Company, which Jetta later assigned to Bird
            Creek.(1)

      c.    Bee-Tree Texas Limited Partnership, partially executed in or about
            July, 1989, by Bee-Tree.(2)

      d.    Sanvin, Inc., dated March 1, 1990

      e.    Richome Oil Company, a partnership of J. B. Herrman and R. P.
            Herrman, dated February 15, 1974.

      f.    T. Leon Brown, d/b/a Leejan Oil Company, dated June 17, 1985.

5.    Master Service Agreement (Greenwood C-1 wellhead compressor) dated July
      24, 2000, between Colorado Interstate Gas Company and USA Compression,
      Inc.


--------------
(1) No records regarding the assignments from Coastal Oil & Gas Corporation to
    Jetta Production Company, nor from Jetta Production Company were made
    available to CIG in Colorado Springs.

(2) The Service Agreement was executed in duplicate by Bee-Tree Texas Limited
    Partnership, however, CIG did not execute either copy.

(3) Copy unavailable.


                                       8
<PAGE>
                             EXHIBIT 5.3 (B)(ii)(6)
                                      LIENS

                                      NONE







                                       1
<PAGE>

                                 EXHIBIT 7.1(D)
                         AUTHORIZATION FOR EXPENDITURES



                                      NONE












                                       2
<PAGE>
                                 EXHIBIT 7.1 (E)
                            CONTRACTUAL RESTRICTIONS


                                      NONE

















                                       1
<PAGE>
                                 EXHIBIT 7.1(F)
                                   LITIGATION

                                      NONE














                                       2
<PAGE>
                                 EXHIBIT 7.1(I)
                                  TAX LIABILITY


The Comptroller's Office of the State of Texas issued a Notification of Audit
Results dated April 21, 1997 asserting that Seller underpaid its severance tax
obligation for the period January 1, 1992 through June 30, 1996. Subsequently,
Seller and the staff of the Comptroller's Office reached agreement (assigned
Hearing No. 37,792) that Seller had actually overpaid and was entitled to a net
refund for this period of $310,153.77, which Seller took in the form of a credit
against taxes for the year 1998. The Comptroller's Office has not yet signed the
order formalizing the agreement. CIG has flowed the credit through the
Administrative Fee under the Pioneer Operating Agreement.







                                       1
<PAGE>
                                 EXHIBIT 7.1 (L)
                                VALID AGREEMENTS

                                      NONE














                                       2