Document:

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                                                                    EXHIBIT 10.F

                              CIG JOINDER AGREEMENT

         THIS CIG JOINDER AGREEMENT, dated as of December 23, 2003 (this
"Joinder Agreement"), is being entered into to effectuate Colorado Interstate
Gas Company, a Delaware corporation ("CIG"), becoming a party to that certain
Security and Intercreditor Agreement, dated as of April 16, 2003 (the
"Intercreditor Agreement"), by and among El Paso Corporation, a Delaware
corporation, JPMorgan Chase Bank, a New York banking corporation ("JPMorgan"),
in its capacity as Credit Agreement Administrative Agent and as Representative
Agent for the Lenders, JPMorgan in its capacity as Collateral Agent for the
Secured Parties, Intercreditor Agent and Depository Bank, and the Pipeline
Company Borrowers, the Grantors and the Representative Agents party thereto.
This Joinder Agreement is made and entered into by and between CIG and the
current parties to the Intercreditor Agreement (including CIG Parent pursuant to
the CIG Parent Joinder Agreement being entered into simultaneously herewith).
Each capitalized term used herein, unless otherwise defined herein, shall have
the meaning ascribed to such term in Appendix A-1 to the Intercreditor
Agreement.

         NOW, THEREFORE, IT IS AGREED:

         Section 1. Joinder. By executing and delivering this Joinder Agreement,
which shall, for all purposes, be deemed to constitute an executed counterpart
to the Intercreditor Agreement, from and after the date hereof, CIG is and shall
be a Pipeline Company Borrower under the Intercreditor Agreement, and is and
shall be bound by, and subject to, all of the terms and provisions of the
Intercreditor Agreement to the same extent as each other Pipeline Company
Borrower under the Intercreditor Agreement. From and after the date hereof, upon
execution and delivery of this CIG Joinder Agreement, all references in the
Intercreditor Agreement to a "Pipeline Company Borrower" shall also mean and be
a reference to CIG.

         Section 2. Rights and Obligations. CIG shall have all of the rights of
a Pipeline Company Borrower under the Intercreditor Agreement and shall have,
and hereby agrees to perform, all of the obligations, duties, and liabilities of
a Pipeline Company Borrower under the Intercreditor Agreement.

         Section 3. Supplements to Schedules. Schedules V and VI of the
Intercreditor Agreement are hereby amended by supplementing such Schedules with
the information relating to CIG set forth in Schedules V and VI hereof.

         Section 4. Representations and Warranties. CIG hereby (a) represents
and warrants that the information on each Schedule to this Joinder Agreement is
complete and accurate and (b) makes each of the representations and warranties
applicable to Credit Parties contained in Section 3.01 of the Intercreditor
Agreement, to the same extent as each other Credit Party (as applicable).

         SECTION 5. GOVERNING LAW. THIS JOINDER AGREEMENT SHALL BE GOVERNED BY,
AND CONSTRUED AND INTERPRETED IN ACCORDANCE WITH, THE LAWS OF THE STATE OF NEW
YORK.

                         [Signatures begin on next page]

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      IN WITNESS WHEREOF, the undersigned has caused this Joinder Agreement
to be duly executed and delivered by its proper and duly authorized officer as
of this 23rd day of December, 2003.

PIPELINE COMPANY BORROWERS:           COLORADO INTERSTATE GAS COMPANY

                                      By:   /s/ Greg G. Gruber
                                         ---------------------------------------
                                         Name:  Greg G. Gruber
                                         Title: Senior Vice President and Chief
                                                Financial Officer

                                      EL PASO NATURAL GAS COMPANY

                                      By:   /s/ Greg G. Gruber
                                         ---------------------------------------
                                         Name:  Greg G. Gruber
                                         Title: Senior Vice President and Chief
                                                Financial Officer

                                      TENNESSEE GAS PIPELINE COMPANY

                                      By:   /s/ Greg G. Gruber
                                         ---------------------------------------
                                         Name:  Greg G. Gruber
                                         Title: Senior Vice President and Chief
                                                Financial Officer

                                      ANR PIPELINE COMPANY

                                      By:   /s/ Greg G. Gruber
                                         ---------------------------------------
                                         Name:  Greg G. Gruber
                                         Title: Senior Vice President and Chief
                                                Financial Officer

                                Signature Page 1
                              CIG Joinder Agreement

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THE COMPANY:                          EL PASO CORPORATION

                                      By:   /s/ John J. Hopper
                                         ---------------------------------------
                                         Name:  John J. Hopper
                                         Title: Vice President and Treasurer

GRANTORS:                             AMERICAN NATURAL RESOURCES COMPANY

                                      By:   /s/ Greg G. Gruber
                                         ---------------------------------------
                                         Name:  Greg G. Gruber
                                         Title: Senior Vice President and Chief
                                                Financial Officer

                                      EL PASO ANR INVESTMENTS, L.L.C.

                                      By:   /s/ Greg G. Gruber
                                         ---------------------------------------
                                         Name:  Greg G. Gruber
                                         Title: Senior Vice President and Chief
                                                Financial Officer

                                      EL PASO ANRS INVESTMENTS, L.L.C.

                                      By:   /s/ Greg G. Gruber
                                         ---------------------------------------
                                         Name:  Greg G. Gruber
                                         Title: Senior Vice President and Chief
                                                Financial Officer

                                      EL PASO CNG COMPANY, L.L.C.

                                      By:   /s/ Greg G. Gruber
                                         ---------------------------------------
                                         Name:  Greg G. Gruber
                                         Title: Senior Vice President and Chief
                                                Financial Officer

                                Signature Page 2
                              CIG Joinder Agreement

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                                      EL PASO EPN INVESTMENTS, L.L.C.

                                      By:   /s/ John J. Hopper
                                         ---------------------------------------
                                         Name:  John J. Hopper
                                         Title: Vice President

                                      EL PASO EPNG INVESTMENTS, L.L.C.

                                      By:   /s/ John J. Hopper
                                         ---------------------------------------
                                         Name:  John J. Hopper
                                         Title: Vice President

                                      EL PASO NORIC INVESTMENTS I, L.L.C.

                                      By:   /s/ Greg G. Gruber
                                         ---------------------------------------
                                         Name:  Greg G. Gruber
                                         Title: Senior Vice President and Chief
                                                Financial Officer

                                      EL PASO NORIC INVESTMENTS III, L.L.C.

                                      By:   /s/ Greg G. Gruber
                                         ---------------------------------------
                                         Name:  Greg G. Gruber
                                         Title: Senior Vice President and Chief
                                                Financial Officer

                                      EL PASO NORIC INVESTMENTS IV, L.L.C.

                                      By:   /s/ Greg G. Gruber
                                         ---------------------------------------
                                         Name:  Greg G. Gruber
                                         Title: Senior Vice President and Chief
                                                Financial Officer

                                Signature Page 3
                              CIG Joinder Agreement

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                                      EL PASO TENNESSEE PIPELINE CO.

                                      By:   /s/ John J. Hopper
                                         ---------------------------------------
                                         Name:  John J. Hopper
                                         Title: Vice President

                                      EL PASO TGPC INVESTMENTS, L.L.C.

                                      By:   /s/ John J. Hopper
                                         ---------------------------------------
                                         Name:  John J. Hopper
                                         Title: Vice President

                                      EL PASO WIC INVESTMENTS, L.L.C.

                                      By:   /s/ Greg G. Gruber
                                         ---------------------------------------
                                         Name:  Greg G. Gruber
                                         Title: Senior Vice President and Chief
                                                Financial Officer

                                      NORIC HOLDINGS III, L.L.C.

                                      By:   /s/ Greg G. Gruber
                                         ---------------------------------------
                                         Name:  Greg G. Gruber
                                         Title: Senior Vice President and Chief
                                                Financial Officer

                                      SABINE RIVER INVESTORS I, L.L.C.

                                      By:   /s/ John J. Hopper
                                         ---------------------------------------
                                         Name:  John J. Hopper
                                         Title: Vice President

                                Signature Page 4
                              CIG Joinder Agreement
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                                      SABINE RIVER INVESTORS II, L.L.C.

                                      By:   /s/ John J. Hopper
                                         ---------------------------------------
                                         Name:  John J. Hopper
                                         Title: Vice President

                                      SABINE RIVER INVESTORS III, L.L.C.

                                      By:   /s/ John J. Hopper
                                         ---------------------------------------
                                         Name:  John J. Hopper
                                         Title: Vice President

                                      SABINE RIVER INVESTORS IV, L.L.C.

                                      By:   /s/ Greg G. Gruber
                                         ---------------------------------------
                                         Name:  Greg G. Gruber
                                         Title: Senior Vice President and Chief
                                                Financial Officer

                                      SABINE RIVER INVESTORS V, L.L.C.

                                      By:   /s/ Greg G. Gruber
                                         ---------------------------------------
                                         Name:  Greg G. Gruber
                                         Title: Senior Vice President and Chief
                                                Financial Officer

                                Signature Page 5
                              CIG Joinder Agreement
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DEPOSITORY BANK:                      JPMORGAN CHASE BANK, as Depository Bank

                                      By:   /s/ James M. Foley
                                         ---------------------------------------
                                         Name:  James M. Foley
                                         Title: Assistant Vice President

COLLATERAL AGENT:                     JPMORGAN CHASE BANK, as Collateral Agent

                                      By:   /s/ James M. Foley
                                         ---------------------------------------
                                         Name:  James M. Foley
                                         Title: Assistant Vice President

INTERCREDITOR AGENT:                  JPMORGAN CHASE BANK, as Intercreditor
                                      Agent

                                      By:   /s/ James M. Foley
                                         ---------------------------------------
                                         Name:  James M. Foley
                                         Title: Assistant Vice President

CREDIT AGREEMENT                      JPMORGAN CHASE BANK, as Credit Agreement
ADMINISTRATIVE AGENT,                 Administrative Agent, 3-Year Facility
3-YEAR FACILITY AGENT,                Agent, Representative Agent for Lakeside,
REPRESENTATIVE AGENT FOR              and Representative Agent for certain
LAKESIDE, AND REPRESENTATIVE          Additional Covered Letters of Credit
AGENT FOR CERTAIN ADDITIONAL
COVERED LETTER(S) OF CREDIT:
                                      By:   /s/ Peter M. Ling
                                         ---------------------------------------
                                         Name:  Peter M. Ling
                                         Title: Managing Director

                                Signature Page 6
                              CIG Joinder Agreement

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REPRESENTATIVE AGENT FOR              CITICORP NORTH AMERICA, INC., as
COSCOL/ARUBA:                         Representative Agent

                                      By:   /s/ Amy Pincu
                                         ---------------------------------------
                                         Name:  Amy Pincu
                                         Title: Vice President
                                                Citicorp North America, Inc.
                                                713/654-2820

REPRESENTATIVE AGENT                  CITIBANK, N.A.
FOR CERTAIN ADDITIONAL
COVERED LETTER(S)
OF CREDIT:                            By: /s/ Amy Pincu
                                         ---------------------------------------
                                         Name:
                                         Title:

                                Signature Page 7
                              CIG Joinder Agreement

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REPRESENTATIVE AGENT FOR              ROYAL BANK OF CANADA, as Representative
COASTAL PETROCHEMICAL:                Agent

                                      By:   /s/ Gail W. Atkins
                                         ---------------------------------------
                                         Name:  Gail W. Atkins
                                         Title: V.P.

                                Signature Page 8
                              CIG Joinder Agreement

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REPRESENTATIVE AGENT FOR              DEUTSCHE BANK TRUST COMPANY AMERICAS,
HARBORTOWN:                           as Representative Agent

                                      By: /s/ M.M. Tarking
                                         ---------------------------------------
                                         Name:
                                         Title:

                                Signature Page 9
                              CIG Joinder Agreement

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REPRESENTATIVE AGENT FOR              MIZUHO CORPORATE BANK (USA), as
NOVA SCOTIA 1999:                     Representative Agent

                                      By:   /s/ Noel P. Puerell
                                         ---------------------------------------
                                         Name:  Noel P. Puerell
                                         Title: Senior Vice President

REPRESENTATIVE AGENT FOR              MIZUHO CORPORATE BANK, LTD., as
NOVA SCOTIA 2000:                     Representative Agent

                                      By:   /s/ Noel P. Puerell
                                         ---------------------------------------
                                         Name:  Noel P. Puerell
                                         Title: Senior Vice President

                                Signature Page 10
                              CIG Joinder Agreement

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REPRESENTATIVE AGENT                  BNP PARIBAS
FOR CERTAIN ADDITIONAL
COVERED LETTER(S)
OF CREDIT:                            By:   /s/ Larry Robinson
                                         ---------------------------------------
                                         Name:  Larry Robinson
                                         Title: Director

                                      /s/ Evans R. Swann
                                      ------------------------------------------
                                      Evans R. Swann
                                      Director

                                Signature Page 11
                              CIG Joinder Agreement

<PAGE>

REPRESENTATIVE AGENT                  THE BANK OF NEW YORK
FOR CERTAIN ADDITIONAL
COVERED LETTER(S)
OF CREDIT:                            By: N/A
                                         ---------------------------------------
                                         Name:
                                         Title:

                                Signature Page 12
                              CIG Joinder Agreement

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REPRESENTATIVE AGENT                  THE TORONTO-DOMINION BANK
FOR CERTAIN ADDITIONAL
COVERED LETTER(S)
OF CREDIT:                            By:   /s/ Jano Nixon
                                         ---------------------------------------
                                         Name:  Jano Nixon
                                         Title: Mgr. Syndications & Credit
                                                Admin.

                                Signature Page 13
                              CIG Joinder Agreement

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REPRESENTATIVE AGENT                  THE BANK OF NOVA SCOTIA
FOR CERTAIN ADDITIONAL
COVERED LETTER(S)
OF CREDIT:                            By:   /s/ N. Bell
                                         ---------------------------------------
                                         Name:  N. Bell
                                         Title: Senior Manager

                                Signature Page 14
                              CIG Joinder Agreement

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                                   SCHEDULE V

                 NAME, LOCATION, CHIEF EXECUTIVE OFFICE, TYPE OF
                 ORGANIZATION, JURISDICTION OF ORGANIZATION AND
                      ORGANIZATIONAL IDENTIFICATION NUMBER

<Table>
<Caption>
                               CHIEF
                               EXECUTIVE         TYPE OF             JURISDICTION OF        ORGANIZATIONAL
GRANTOR          LOCATION      OFFICE            ORGANIZATION        ORGANIZATION           I.D. NO.
-------          --------      ---------         ------------        ---------------        --------------
<S>              <C>           <C>               <C>                 <C>                    <C>
</Table>

                    No modification necessary for Schedule V.

                                   Schedule V
                              CIG Joinder Agreement

<PAGE>

                                   SCHEDULE VI

                                   TRADE NAMES

I. TRADE NAMES

NAMES
-----

None.

                                   Schedule VI
                              CIG Joinder Agreement<PAGE>

                                                                   EXHIBIT 10.24

                                    Amendment
                                       To
           Non-Qualified Retirement/Savings Plan of Apache Corporation

Apache Corporation ("Apache") maintains the Non-Qualified Retirement/Savings
Plan of Apache Corporation (the "Plan"). Pursuant to section 8.02 of the Plan,
Apache has retained the right to amend the Plan. Apache hereby exercises that
right, effective for distributions after January 1, 2004, to replace section
5.02(b) of the Plan in its entirety by the following.

         (b)      Form of Distribution.

                  (i)      Alternatives. The Participant's vested Account shall
                           be distributed in a single payment unless the
                           Participant makes an effective election to receive
                           from two to ten annual installments.

                  (ii)     Payout Election.

                           (A)      Initial Election. Upon becoming a
                                    Participant, an Employee may make a payout
                                    election to have his vested Account paid out
                                    in from two to ten annual installments. To
                                    be effective, the Participant's initial
                                    payout election must be made before, or
                                    within 30 days after, his participation
                                    begins. If the Participant does not make a
                                    timely initial payout election, he shall be
                                    treated as if he elected a single payment.

                           (B)      Making a New Payout Election. A Participant
                                    may change his payout election at any time,
                                    subject to the procedures that the Committee
                                    has implemented at that time. A revised
                                    payout election shall not be effective until
                                    one of the following events occurs:

                                    (1)      The Participant completes one full
                                             year of employment with the Company
                                             and Affiliated Entities immediately
                                             after the Plan receives the new
                                             payout election. An FMLA leave and
                                             a USERRA leave shall be treated as
                                             continuous employment, but only if
                                             the Participant returns to active
                                             employment for at least one month
                                             after the leave expires.

                                    (2)      The Participant incurs a Disability
                                             while an Employee.

                  (iii)    Rules for Installment Payments. The minimum annual
                           installment payment shall be $50,000, or, if less,
                           the Participant's remaining Account balance; this
                           rule may result in the Participant receiving fewer
                           installment payments than he elects. Each installment
                           will be equal to the greater of (A) the minimum
                           annual installment, or (B) the vested Account balance
                           at the beginning of the Plan Year divided by the
                           number of remaining annual installments, except for
                           the final

                                   Page 1 of 2

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                           installment, which will be equal to the remaining
                           Account balance. Installments will be paid as soon as
                           administratively convenient during the Plan Year.

                           For example, if the Participant had chosen 5 annual
                           installments, and terminates employment in February
                           of 1999,

                           - the unvested Account balance shall be forfeited
                             immediately;

                           - his 1999 installment will be one-fifth of his
                             January 1, 1999 vested Account balance;

                           - his 2000 installment will be one-fourth of his
                             January 1, 2000 Account balance;

                           - his 2001 installment will be one-third of his
                             January 1, 2001 Account balance;

                           - his 2002 installment will be one-half of his
                             January 1, 2002 Account balance; and

                           - his final installment in 2003 will be the remainder
                             of his Account balance.

IN WITNESS WHEREOF, this Amendment has been executed the date set forth below.

                                          APACHE CORPORATION

                                          By: /s/ Jeffrey M. Bender
                                              -------------------------------

         Date: December 18, 2003          Title: Vice President, Human Resources

                                   Page 2 of 2

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