<PAGE>
 

<TABLE>
<CAPTION>

        Enogex
        ------

Pre-Closing                      Post-Closing
- -----------                      ------------
<S>                              <C> 
Enogex Products Corporation      Enogex Products Corporation
600 Central Park Two             600 Central Park Two
515 Central Park Drive           515 Central Park Drive
Oklahoma City, Oklahoma 73105    Oklahoma City, Oklahoma 73105
Attn.:  Roger A. Farrell         Attn.: Director of Gas Processing
Fax: (405) 558-4618              Fax: (405) 557-5258
</TABLE>

or to such other address as the person to whom notice is given may have
previously furnished to the others in writing in the manner set forth above
(provided that notice of any change of address shall be effective only upon
receipt thereof).

  9.4  Public Announcements.  Neither party to the transfer of the Texas Assets
or to the Oklahoma Assets, respectively, may make press releases or other public
announcements concerning the relevant portion of this transaction, without the
other affected party's prior approval and agreement to the form of the
announcement, except as may be required by applicable laws or rules and
regulation of any governmental agency or stock exchange.

  9.5  Exhibits.  The Exhibits attached to this Agreement are incorporated into
and made a part of this Agreement.  In the event of a conflict between the
provisions of the Exhibits or the executed  Closing documents and the foregoing
provisions of this Agreement, the provisions of this Agreement shall take
precedence.  In the event of a conflict between the provisions of the pro forma
Closing documents attached to this Agreement as Exhibits and the Closing
documents actually executed by the parties, the provisions of the executed
Closing documents shall take precedence.  The omission of certain provisions of
this Agreement from the Closing documents does not constitute a conflict between
this Agreement and the Closing documents and will not effect a merger of the
omitted provisions.

  9.6  Integration and Amendment.  This Agreement represents the entire
agreement between the parties, superseding all prior negotiations, and may not
be amended or modified except by written agreement between duly authorized
representatives of the parties.

  9.7  Successors and Assigns.  This Agreement binds and inures to the benefit
of the parties hereto their respective permitted successors and assigns, and
nothing contained in this Agreement, express or implied, is intended to confer
upon any other person or entity any benefits, rights, or remedies.  Neither this
Agreement, the agreements contemplated hereby nor any of the rights, interests
and obligations hereunder or thereunder shall be

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