LETTER TO DTC PARTICIPANTS REGARDING THE OFFER TO EXCHANGE
          ANY AND ALL OUTSTANDING 12.50% SENIOR SECURED NOTES DUE 2006
                                      FOR
                      12.50% SENIOR SECURED NOTES DUE 2006
                                       OF
                       TRI-UNION DEVELOPMENT CORPORATION
          WHICH HAVE BEEN REGISTERED UNDER THE SECURITIES ACT OF 1933

               PURSUANT TO THE PROSPECTUS DATED NOVEMBER 2, 2001



THE EXCHANGE OFFER WILL EXPIRE AT 5:00 P.M., NEW YORK CITY TIME ON DECEMBER 10,
                                      2001

        UNLESS EXTENDED (SUCH TIME AND DATE, AS THE SAME MAY BE EXTENDED

      FROM TIME TO TIME, THE "EXPIRATION DATE"). TENDERS MAY BE WITHDRAWN

                   AT ANY TIME PRIOR TO THE EXPIRATION DATE.

       DTC PARTICIPANTS MUST RETURN THE ENCLOSED CLIENT INFORMATION SHEET
       (TO BE COMPLETED BY THE BENEFICIAL HOLDERS) TO THE EXCHANGE AGENT.


                                                               November   , 2001


To Brokers, Dealers, Commercial Banks,
Trust Companies and Other Nominees:


     Tri-Union Development Corporation ("Tri-Union") is enclosing herewith the
material listed below in connection with its offer to exchange new 12.50% Senior
Secured Notes due 2006 ("New Notes") that have been registered under the
Securities Act of 1933, as amended (the "Securities Act"), for all of its
outstanding 12.50% Senior Secured Notes due 2006 (the "Old Notes"), upon the
terms and subject to the conditions set forth in the prospectus, dated November
2, 2001 (the "Prospectus"), and in the accompanying Letter of Transmittal (the
"Letter of Transmittal") which together constitute the "Exchange Offer."
Capitalized terms used but not defined herein have the respective meanings
ascribed to them in the Prospectus.


     Enclosed herewith are copies of the following documents:


          1. The Prospectus;

          2. The Letter of Transmittal for your use and for the information of
     your clients, together with guidelines of the Internal Revenue Service for
     Certification of Taxpayer Identification Number on Substitute Form W-9
     providing information relating to backup Federal income tax withholding;

          3. The Notice of Guaranteed Delivery to be used to accept the Exchange
     Offer if the Old Notes and all other required documents cannot be delivered
     to the exchange agent prior to the Expiration Date;

          4. A form of letter which MUST be sent to your clients for whose
     account you hold Old Notes in your name or in the name of a nominee, with
     space provided for obtaining such clients' instructions with regard to the
     Exchange Offer and a Client Information Sheet related to certain state
     jurisdictional issues (NOTE: THIS CLIENT INFORMATION SHEET MUST BE
     COMPLETED BY THE BENEFICIAL HOLDER AND RETURNED BY YOU TO THE EXCHANGE
     AGENT); and

          5. A return envelope addressed to the exchange agent.

     DTC Participants will be able to execute tenders and deliver consents
through the DTC Automated Tender Offer Program.


PLEASE NOTE THAT THE EXCHANGE OFFER WILL EXPIRE AT 5:00 P.M., NEW YORK CITY
TIME, ON DECEMBER 10, 2001, UNLESS EXTENDED BY TRI-UNION. WE URGE YOU TO CONTACT
YOUR CLIENTS AS PROMPTLY AS POSSIBLE. THE CLIENT INFORMATION SHEET, TO BE FILLED
OUT BY YOUR CLIENT, MUST BE RETURNED TO THE EXCHANGE AGENT.


     You will be reimbursed for customary mailing and handling expenses incurred
by you in forwarding the enclosed materials to your clients.

     Additional copies of the enclosed materials may be obtained from the
exchange agent, at the address and telephone numbers set forth in the Prospectus
and the Letter of Transmittal.

                                         Very truly yours,

                                         Tri-Union Development Corporation

                             ---------------------

NOTHING CONTAINED HEREIN OR IN THE ENCLOSED DOCUMENTS SHALL CONSTITUTE YOU OR
ANY OTHER PERSON AS THE AGENT OF TRI-UNION OR THE EXCHANGE AGENT OR AUTHORIZE
YOU OR ANY OTHER PERSON TO GIVE ANY INFORMATION OR MAKE ANY REPRESENTATION ON
BEHALF OF ANY OF THEM WITH RESPECT TO THE EXCHANGE OFFER NOT CONTAINED IN THE
PROSPECTUS OR THE LETTER OF TRANSMITTAL.

DTC PARTICIPANTS MUST RETURN THE CLIENT INFORMATION SHEET CONTAINING IMPORTANT
INFORMATION RELATED TO STATE JURISDICTIONAL ISSUES TO THE EXCHANGE AGENT.

                                        2