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                                                                 Exhibit 10.9(a)

                        FIRST AMENDMENT TO AMENDED AND
                    RESTATED AGREEMENT OF LIMITED PARTNERSHIP
                                       OF
                   NOARK PIPELINE SYSTEM, LIMITED PARTNERSHIP

      This FIRST AMENDMENT TO AMENDED AND RESTATED AGREEMENT OF LIMITED
PARTNERSHIP OF NOARK PIPELINE SYSTEM, LIMITED PARTNERSHIP (this "First
Amendment") dated as of June 18,1998 amends that certain Amended and Restated
Agreement of Limited Partnership of NOARK Pipeline System, Limited Partnership
dated as of January 12, 1998 (the "Partnership Agreement") between Southwestern
Energy Pipeline Company, as a general partner, and Enogex Arkansas Pipeline
Corporation, as a general partner and a limited partner. Capitalized terms used
herein and not defined herein shall have the meanings assigned thereto in the
Partnership Agreement.

      In consideration of the mutual promises made herein, and for other good
and valuable consideration the receipt and sufficiency of which are hereby
acknowledged, the Partners hereby agree as follows:

1.          The definition of "Existing Loans" in Section 1.1 of the
      Partnership Agreement is hereby amended in its entirety to read as
      follows:

      " "Existing Loans" means the NOARK Debt, and any subsequent loans to the
      Partnership or any NOARK Related Entity replacing the then existing
      principal balance of the NOARK Debt, or the then existing principal
      balance of such subsequent loans, as applicable."

2.          The definition of "NOARK Debt" in Section 1.1 of the Partnership
      Agreement is hereby amended by inserting at the end thereof, the
      following:

      "; provided, however, that from and after June 18, 1998 "NOARK Debt" shall
      mean the Finance Notes, and shall exclude for all purposes of this
      Agreement the debt incurred by the Partnership pursuant to the terms of
      that certain Loan Agreement dated as of June 1, 1998 between the
      Partnership and NOARK Pipeline Finance, L.L.C., an Oklahoma limited
      liability company."

3.          Section 1.1 of the Partnership Agreement is hereby amended by
      inserting the following definitions:

      "Defaulting Guarantor" shall have the meaning assigned thereto in the
      Indenture.

      "EAPC Allocated Existing Loans" shall mean, at any time after indebtedness
      is incurred pursuant to the last sentence of Section 3 4 b ) hereof, (i)
      40% of the Existing Loans immediately prior to the incurrence of such
      indebtedness and the application of the proceeds thereof; less, if and
      only if southwestern Energy Company is the Defaulting Guarantor (as
      defined in the Indenture), the principal amount of Finance Notes redeemed
      upon application of the proceeds of such

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      indebtedness and (ii) if and only if Southwestern Energy Company is the
      Defaulting Guarantor, the indebtedness incurred pursuant to the last
      sentence of Section 3.5(b) hereof, and any subsequent loans to the
      Partnership replacing the principal balance thereof at the time such
      subsequent loans are made.

      "Enogex Guaranty" shall have the meaning assigned thereto in the
      Indenture.

      "Finance Notes" shall mean the 7.15% Notes Due 201 8 issued by NOARK
      Pipeline Finance, L.L.C. in the original aggregate principal amount of
      $80,000,000 pursuant to the Indenture.

      "Indenture" shall mean the Indenture dated as of June 1, 1998 between the
      NOARK Pipeline Finance, L.L.C. and The Bank of New York, as trustee, as it
      may be amended or supplemented from time to time.

      "Non-Defaulting Guarantor" shall have the meaning assigned thereto in the
      Indenture.

      "Southwestern Guaranty" shall have the meaning assigned thereto in the
      Indenture.

      "SWPL Allocated Existing Loans" shall mean, at any time after indebtedness
      is incurred pursuant to the last sentence of Section 3.5(b) hereof, the
      sum of (i) 60% of the Existing Loans immediately prior to the incurrence
      of such indebtedness and the application of the proceeds thereof, less, if
      and only if Enogex Inc. is the Defaulting Guarantor (as defined in the
      Indenture), the principal amount of Finance Notes redeemed upon
      application of the proceeds of such indebtedness and (ii) if and only if
      Enogex Inc. is the Defaulting Guarantor, the indebtedness incurred
      pursuant to the last sentence of Section 3.5(b) hereof, and any subsequent
      loans to the Partnership replacing the principal balance thereof at the
      time such subsequent loans are made.

4.          Subsection (b) of Section 3.5 of the Partnership Agreement is
      hereby amended as follows:

            (i)   by inserting the words "by the Partnership (including any
                  NOARK Related Entity)" immediately after the words
                  "indebtedness for borrowed money" in the first line thereof;
                  and

            (ii)  by inserting at the end of said subsection (b), the following
                  sentence:

      "Notwithstanding the foregoing, (i) if Southwestern Energy Company shall
      be a Defaulting Guarantor and Enogex Inc. shall be a Non-Defaulting
      Guarantor, the Partnership, at the direction of EAPC, may incur
      indebtedness for borrowed money (x) upon a declaration of acceleration of
      the Finance Notes pursuant to Section 6.l(b) of the Indenture, in a
      principal amount equal to the Guaranteed Principal Amount (as defined in
      the Enogex Guaranty) or (y) otherwise, in a

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      principal amount equal to the Redemption Price (as defined in the
      Indenture) applicable to the redemption of Finance Notes in an aggregate
      principal amount equal to the Guaranteed Principal Amount (as defined in
      the Enogex Guaranty), in each case without the consent of the
      SuperMajority in Interest of Partners, and the proceeds of such
      indebtedness shall be applied on behalf of Enogex Inc. to the payment of
      the Finance Notes upon acceleration thereof or to the redemption of
      Finance Notes pursuant to Section 3.l(b) of the Indenture, as applicable,
      and (ii) if Enogex Inc. shall be a Defaulting Guarantor and Southwestern
      Energy Company shall be a Non-Defaulting Guarantor, the Partnership may,
      at the direction of SWPL, incur indebtedness for borrowed money (x) upon a
      declaration of acceleration of the Finance Notes pursuant to Section 6.1
      (b) of the Indenture, in a principal amount equal to the Guaranteed
      Principal Amount (as defined in the Southwestern Guaranty) or (y)
      otherwise, in a principal amount equal to the Redemption Price (as defined
      in the Indenture) applicable to the redemption of Finance Notes in an
      aggregate principal amount equal to the Guaranteed Principal Amount (as
      defined in the Southwestern Guaranty), in each case without the consent of
      the SuperMajority in Interest of Partners, and the proceeds of such
      indebtedness shall be applied on behalf of Southwestern Energy Company to
      the payment of the Finance Notes upon acceleration thereof or to the
      redemption of Finance Notes pursuant to Section 3.l(b) of the Indenture;
      provided that any indebtedness incurred pursuant to this sentence without
      the consent of the SuperMajority in Interest of Partners shall be
      unsecured, shall be non-recourse to each of the Partners (unless with
      respect to either Partner, such Partner shall otherwise consent in
      writing) and shall not contain any -. covenants, agreements or provisions
      which would in any material respect be more restrictive on the Partnership
      and the NOARK Related Entities and their respective businesses and affairs
      than the covenants, agreements or provisions of the Indenture and the
      Finance Notes. In the event that EAPC directs the Partnership to incur
      indebtedness as described in the preceding sentence, (i) EAPC, on behalf
      of the Partnership, and the Partnership are hereby authorized to take such
      action as may be reasonably required in order for the Partnership to incur
      such indebtedness in conformity with the requirements of the preceding
      sentence, without any further action by the Partners or the Management
      Committee and (ii) SWPL shall take all such actions and execute any and
      all documents reasonably required by it as a general partner of the
      Partnership to facilitate the incurrence of such indebtedness by the
      Partnership; provided that SWPL shall not incur any liability in respect
      thereof. In the event that SWPL directs the Partnership to incur
      indebtedness as described in the preceding sentence, (i) SWPL, on behalf
      of the Partnership, and the Partnership are hereby authorized to take such
      action as may be reasonably required in order for the Partnership to incur
      such indebtedness in conformity with the requirements of the second
      preceding sentence, without any further action by the Partners or the
      Management Committee and (ii) EAPC shall take all such actions and - . ,
      execute any and all documents reasonably required by it as a general
      partner of the Partnership to facilitate the incurrence of such
      indebtedness by the Partnership; provided that EAPC shall not incur any
      liability in respect thereof.

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5.          Section 4.2(c) of the Partnership Agreement is hereby amended in
      its entirety to read as follows:

      (a)   The Partners agree that (i) prior to the incurrence of any
            indebtedness pursuant to the last sentence of Section 3.5(b), the
            Existing Loans, including applicable interest, shall be repaid as
            follows: (x) sixty percent (60%) of the Existing Loans, including
            applicable interest, shall be repaid out of any amounts otherwise
            distributable to SWPL, before taking into account debt service on
            the Existing Loans, under this Agreement and (y) forty percent (40%)
            of the Existing Loans, including applicable interest, shall be
            repaid out of any amounts otherwise distributable to EAPC, before
            taking into account debt service on the Existing Loans, under this
            Agreement, and (ii) from and after the incurrence of any
            indebtedness pursuant to the last sentence of Section 3.5(b), the
            Existing Loans, including applicable interest, shall be repaid as
            follows: (x) the SWPL Allocated Existing Loans, including applicable
            interest, shall be repaid out of any amounts otherwise distributable
            to SWPL, before taking into account debt service on the Existing
            Loans, under this Agreement and (y) the EAPC Allocated Existing
            Loans, including applicable interest, shall be repaid out of any
            amounts otherwise distributable to EAPC, before taking into account
            debt service on the Existing Loans, under this Agreement. If such
            amounts referred to in clause (i) of the preceding sentence are
            insufficient to pay a Partner's percentage share (i.e. 60% or 40% as
            set forth above) of the debt service on the Existing Loans,
            including applicable interest, in accordance with their terms, then
            such Partner shall be responsible to contribute to the capital of
            the Partnership amounts sufficient to pay its percentage share (i.e.
            60% or 40% as set forth above) of the debt service on the Existing
            Loans, including applicable interest, and shall do so upon notice
            from the Project Leader. If such amounts referred to in clause (ii)
            of the preceding sentence are insufficient to pay the debt service
            on the SWPL Allocated Existing Loans or the EAPC Allocated Existing
            Loans, in each case including applicable interest, in accordance
            with its respective terms, then SWPL or EAPC, as the case may be,
            shall be responsible to contribute to the capital of the Partnership
            amounts sufficient to pay the debt service on the SWPL Allocated
            Existing Loans or the EAPC Allocated Existing Loans, as applicable,
            including in each case interest thereon, and shall do so upon notice
            from the Project Leader. Notwithstanding the foregoing, if either
            SWPL or EAPC obtains knowledge that it is responsible to contribute
            to the capital of the Partnership pursuant to this Section 4.2(c),
            then such Partner shall be obligated to make such contribution of
            capital to the Partnership on a timely basis notwithstanding the
            fact that the Project Leader has not given notice to such Partner as
            contemplated hereby. Capital Contributions by the Partners pursuant
            to this Section 4.2(c) shall not alter the Partnership Percentages
            of the Partners. Default by a Partner in the making of such

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            Capital Contributions shall cause it to be deemed a Delinquent
            Partner subject to the provisions of Section 4.3 hereof.

6.          Section 4.2(d) of the Partnership Agreement is hereby amended in
      its entirety to read as follows:

      (a)   Notwithstanding anything to the contrary in Section 4.2(c) above or
            elsewhere in this Agreement, it is understood and agreed that the
            terms of any Existing Loans may in the future (but do not currently)
            provide that the amortization of the principal amount thereof shall
            be borne or allocated in a manner different from the percentages set
            forth in Section 4.2(c) or any Partner may direct the Project Leader
            to apply amounts of Partnership cash otherwise distributable to such
            Partner (except amounts to be paid to other Partners pursuant to the
            other provisions of this Agreement) to the repayment or prepayment
            of the principal amount of the Existing Loans in excess of the
            amounts required to be repaid under the terms of the Existing Loans,
            provided such Partner bears all costs and penalties of doing so. In
            addition, either Partner may elect to redeem from such Partner's own
            funds a portion of the Finance Notes pursuant to Section 3.1 of the
            Indenture. Consequently, a Partner may thereby pay or bear more than
            its attributable percentage of the principal amount of the Existing
            Loans to be repaid. In such event, the percentages of the then
            outstanding principal amount of the Existing Loans payable out of
            the distributable amounts attributable to the Partners set forth in
            Section 4.2(c) shall be adjusted as appropriate to reflect the
            resulting percentage of the aggregate outstanding principal amount
            of the Existing Loans then attributable to each Partner.

7.          Section 5.3 of the Partnership Agreement is hereby amended in its
      entirety to read as follows:

            5.3. Special Interest Expense. The Partnership interest expense
      deductions incurred with regard to the Existing Loans and the Finance
      Notes as referenced in Section 4.2(c) shall be allocated to the Partners
      as follows:

            (i) prior to the incurrence of any indebtedness pursuant to the last
            sentence of Section 3.5(b), 60% to SWPL and 40% to EAPC; and

            (ii) following the incurrence of any indebtedness pursuant to the
            last sentence of Section 3.5(b), the Partnership interest expense
            deductions incurred with regard to the SWPL Allocated Existing Loans
            shall be allocated to SWPL and the Partnership interest expense
            deductions incurred with regard to the EAPC Allocated Existing Loans
            shall be allocated to EAPC.

      In the event the percentages of the outstanding principal amounts of the
      Existing Loans payable out of the distributable amounts attributable to
      each Partner are adjusted pursuant to Section 4.2(d), the foregoing
      percentages shall be subject to

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      adjustment to reflect the same percentages as the percentages established
      pursuant to Section 4.2(d).

8.          The Partnership Agreement, as amended hereby, shall remain in
      full force and effect and is hereby ratified, approved and confirmed in
      all respects.

9.          From and after the date hereof, each reference in the Partnership
      Agreement to "this Agreement," "hereof," or "hereunder" or words of like
      import, and all references to the Partnership Agreement in any and all
      agreements, instruments, documents, notes, certificates and other writings
      of every kind and nature shall be deemed to mean the Partnership
      Agreement, as modified and amended by this First Amendment.

10.         THE PROVISIONS OF THIS FIRST AMENDMENT SHALL BE GOVERNED BY AND
      CONSTRUED AND ENFORCED IN ACCORDANCE WITH THE LAWS OF THE STATE OF
      ARKANSAS (EXCLUDING ANY CONFLICTS-OF-LAW RULE OR PRINCIPLE THAT MIGHT
      REFER SAME TO THE LAWS OF ANOTHER JURISDICTION), EXCEPT TO THE EXTENT THAT
      SAME ARE MANDATORILY SUBJECT TO THE LAWS OF ANOTHER JURISDICTION PURSUANT
      TO THE LAWS OF SUCH OTHER JURISDICTION.

11.         This First Amendment may be executed in multiple counterparts,
      each of which shall be deemed an original agreement, and all of which
      shall constitute one agreement, by each of the parties hereto on the dates
      respectively indicated in the signatures of said parties, notwithstanding
      that all of the parties are not signatories to the original or to the same
      counterpart, to be effective as of the day and year hereinabove set forth.

      IN WITNESS WHEREOF, the Partners have executed this First Amendment on the
date first set forth above.

                                      GENERAL PARTNERS:

                                      ENOGEX ARKANSAS PIPELINE
                                      CORPORATION

                                      By: _________________________
                                      Name:    E. Keith Mitchell
                                      Title:   Vice President

                                      SOUTHWESTERN ENERGY
                                      PIPELINE COMPANY

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                               By: _________________________
                               Name:    Stanley D. Green
                               Title:   Executive Vice President - Finance &
                                        Corporate Development

                               LIMITED PARTNER:

                               ENOGEX ARKANSAS PIPELINE
                               CORPORATION

                               By: _________________________
                               Name:    E. Keith Mitchell
                               Title:   Vice President