LETTER TO BENEFICIAL HOLDERS 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       TENDERS MAY BE WITHDRAWN AT ANY TIME PRIOR TO THE EXPIRATION DATE.

      YOU MUST COMPLETE AND RETURN THE ENCLOSED CLIENT INFORMATION SHEET.


                                                              November  _ , 2001


To Our Clients:


     Enclosed for your consideration is the prospectus, dated November 2, 2001
(the "Prospectus"), and the accompanying Letter of Transmittal (the "Letter of
Transmittal") that together constitute the offer (the "Exchange Offer") by
Tri-Union Development Corporation ("Tri-Union") 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. The Prospectus
and the Letter of Transmittal more fully describe the Exchange Offer.
Capitalized terms used but not defined herein have the respective meanings
ascribed to them in the Prospectus.


     To participate in the Exchange Offer, persons in whose names Old Notes are
registered on the books of the registrar ("Registered Holders") must either:

     - cause to be delivered to Firstar Bank, National Association (the
       "Exchange Agent"), at the address set forth in the Letter of Transmittal,
       Old Notes in proper form for transfer, together with a properly executed
       Letter of Transmittal (INCLUDING THE CLIENT INFORMATION SHEET); or

     - cause a DTC Participant to tender such holder's Old Notes to the Exchange
       Agent's account maintained at The Depository Trust Company ("DTC") for
       the benefit of the Exchange Agent through the DTC's Automated Tender
       Offer Program ("ATOP"), including transmission of an agent's message in
       which the Registered Holder acknowledges and agrees to be bound by the
       terms of the Letter of Transmittal, and return completed the enclosed
       client information sheet to the DTC participant.

     By complying with DTC's ATOP procedures with respect to the Exchange Offer,
the DTC Participant confirms on behalf of itself and the beneficial owners of
tendered Old Notes all provisions of the Letter of Transmittal applicable to it
and such beneficial owners as fully as if it completed, executed and returned
the Letter of Transmittal to the Exchange Agent.

     We are the holder of Old Notes held for your account. A tender of such Old
Notes can be made only by us as the holder for your account and pursuant to your
instructions. The enclosed Letter of Transmittal is furnished to you for your
information only and cannot be used to tender Old Notes.

     We request instructions as to whether you wish to tender any or all of the
Old Notes held by us for your account, pursuant to the terms and subject to the
conditions set forth in the Prospectus and the Letter of Transmittal.

     To ensure the Exchange Offer and the tender of Old Notes is in compliance
with state jurisdictional requirements you must complete the enclosed client
information sheet (the "Client Information Sheet").



     Your instructions to us and the Client Information Sheet should be
forwarded as promptly as possible in order to permit us to tender your Old Notes
on your behalf in accordance with the provisions of the Prospectus and the
Letter of Transmittal. The Exchange Offer will expire at 5:00 p.m., New York
City time, on December 10, 2001, unless extended by Tri-Union. Old Notes
properly tendered may be withdrawn at any time prior to the Expiration Date.


     The Exchange Offer is not conditioned upon any minimum number of Old Notes
being tendered.

     Pursuant to the Letter of Transmittal, each holder of Old Notes must
represent to Tri-Union that:

     - the New Notes to be acquired by such holder pursuant to the Exchange
       Offer are being acquired in the ordinary course of business of the
       holder;

     - such holder is not participating, does not intend to participate, and has
       no arrangement or understanding with any person to participate, in the
       distribution of the New Notes;

     - such holder is not an "affiliate," as defined under Rule 405 of the
       Securities Act, of Tri-Union;

     - a holder who is a broker-dealer registered under the Securities Exchange
       Act of 1934, as amended, or who tenders Old Notes in the Exchange Offer
       for the purpose of participating in a distribution of the New Notes will
       comply with the registration and prospectus delivery requirements of the
       Securities Act in connection with any secondary resale transaction and
       cannot rely on the position of the staff of the Securities and Exchange
       Commission enunciated in its series of interpretive "no-action" letters
       with respect to exchange offers;

     - if the holder is a broker-dealer that will receive New Notes for its own
       account in exchange for Old Notes, it must represent that the Old Notes
       to be exchanged for New Notes were acquired as a result of market-making
       activities or other trading activities and must represent that it will
       deliver a prospectus meeting the requirements of the Securities Act in
       connection with any resale of New Notes received in respect of such Old
       Notes pursuant to the Exchange Offer; however, by so representing and by
       delivering a prospectus in connection with the exchange of Old Notes, the
       holder will not be deemed to admit that it is an "underwriter" within the
       meaning of the Securities Act; and

     - if the holder is not a broker-dealer, it must represent that it is not
       engaged in, and does not intend to engage in, a distribution of New
       Notes.

     The enclosed "Instruction to Registered Holder or DTC Participant from
Beneficial Owner" form contains an authorization by you, as the beneficial owner
of Old Notes, for us to make the foregoing representations on your behalf.

     We urge you to read the enclosed Letter of Transmittal in conjunction with
the Exchange Offer carefully before instructing us to tender your Old Notes.

     Your attention is directed to the following:

     - the Exchange Offer is described in and subject to the terms and
       conditions set forth in the Prospectus;

     - subject to the terms and conditions of the Exchange Offer, Tri-Union will
       accept for exchange on the Expiration Date all Old Notes properly
       tendered and will issue New Notes promptly after such acceptance;

     - if you desire to tender any Old Notes pursuant to the Exchange Offer, we
       must receive your instructions and the Client Information Sheet in ample
       time to permit us to effect a tender of the Old Notes on your behalf
       prior to the Expiration Date; and

     - any brokerage fees, commissions or transfer taxes will be borne by
       Tri-Union, except as otherwise provided in Instruction 6 of the Letter of
       Transmittal.

     If you wish to tender any or all of the Old Notes held by us for your
account, please so instruct us by completing, executing, detaching and returning
to us the instruction form attached hereto. If you authorize the tender of your
Old Notes, all such Old Notes will be tendered unless otherwise specified on the
instruction
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form. Your instructions should be forwarded to us in ample time to permit us to
submit a tender on your behalf on or prior to the Expiration Date. The specimen
Letter of Transmittal is furnished to you for your information only and cannot
be used by you to tender Old Notes held by us for your account.

     Tri-Union is not aware of any jurisdiction in which the making of the
Exchange Offer or the tender of Old Notes in connection therewith would not be
in compliance with the laws of such jurisdiction. However, to further ensure the
making of the Exchange Offer and the tender of Old Notes is in compliance with
jurisdictional requirements, please complete, execute, detach and return the
enclosed Client Information Sheet. If Tri-Union becomes aware of any
jurisdiction in which the making of the Exchange Offer would not be in
compliance with such laws, Tri-Union will make a good faith effort to comply
with any such laws or seek to have such laws declared inapplicable to the
Exchange Offer. If, after such good faith effort, Tri-Union cannot comply with
any such laws, the Exchange Offer will not be made to the Registered Holders
residing in such jurisdiction.

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              INSTRUCTIONS TO REGISTERED HOLDER OR DTC PARTICIPANT
         FROM BENEFICIAL OWNER OF 12.50% SENIOR SECURED NOTES DUE 2006
                                       OF
                       TRI-UNION DEVELOPMENT CORPORATION


     The undersigned has received the prospectus dated, November 2, 2001 (the
"Prospectus"), of Tri-Union Development Corporation ("Tri-Union") and the
accompanying Letter of Transmittal, that together constitute Tri-Union's offer
to exchange any and all of its outstanding 12.50% Senior Secured Notes due 2006
(the "Old Notes") for its 12.50% Senior Secured Notes due 2006 which have been
registered under the Securities Act of 1933, as amended (the "Securities Act";
such notes, the "New Notes"; such offer, the "Exchange Offer").


     This will instruct you, the registered holder, as to the action to be taken
by you relating to the Exchange Offer with respect to the Old Notes held by you
for the account of the undersigned, on the terms and subject to the conditions
in the Prospectus and Letter of Transmittal.

     The aggregate face amount of the Old Notes held by you for the account of
the undersigned is (fill in the amount):

     $          of the Old Notes.

     With respect to the Exchange Offer, the undersigned hereby instructs you
(check appropriate box);

     [ ] To TENDER the following Old Notes held by you for the account of the
undersigned (insert principal amount of Old Notes to be tendered, if any):

     $          of the Old Notes.

     [ ] NOT to TENDER any Old Notes held by you for the account of the
undersigned.

     If the undersigned instructs you to tender the Old Notes held by you for
the account of the undersigned, you are authorized:

     - to make, on behalf of the undersigned (and the undersigned, by its
       signature below, hereby makes to you), the representations and warranties
       contained in the Letter of Transmittal that are to be made with respect
       to the undersigned as a beneficial owner of the Old Notes, including but
       not limited to the representations that:

      - the undersigned is acquiring the New Notes in the ordinary course of
        business of the undersigned;

      - the undersigned is not participating, does not intend to participate,
        and has no arrangement or understanding with any person to participate,
        in the distribution of the New Notes;

      - the undersigned is not an "affiliate," as defined under Rule 405 of the
        Securities Act of Tri-Union;

      - any person who is a broker-dealer registered under the Securities
        Exchange Act of 1934, as amended, or is participating in the Exchange
        Offer for the purpose of distributing the New Notes will comply with the
        registration and prospectus delivery requirements of the Securities Act,
        in connection with a secondary resale transaction of the New Notes
        acquired by such person and cannot rely on the position of the staff of
        the Securities and Exchange Commission enunciated in its series of
        interpretative no-action letters with respect to exchange offers;

      - if the undersigned is a broker-dealer that will receive New Notes for
        its own account in exchange for Old Notes, it represents that the Old
        Notes to be exchanged for the New Notes were acquired by it as a result
        of market-making activities or other trading activities and it will
        deliver a prospectus in connection with any resale of such New Notes;
        however, by so acknowledging and by delivering a prospectus, the
        undersigned will not be deemed to admit that it is an "underwriter"
        within the meaning of the Securities Act; and

      - if the undersigned is not a broker-dealer, the undersigned represents
        that it is not engaged in, and does not intend to engage in, a
        distribution of the New Notes;

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     - to agree, on behalf of the undersigned, as set forth in the Letter of
       Transmittal; and

     - to take such other action as necessary under the prospectus or the Letter
       of Transmittal to effect the valid tender of Old Notes.

                                   SIGN HERE

Name of Beneficial Owner(s):
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Signature(s): Name(s) (please print):
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Address:
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Telephone Number(s):
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Taxpayer Identification or Social Security Number(s):
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Date:
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            CLIENT INFORMATION SHEET 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

        THIS FORM MUST BE COMPLETED AND RETURNED TO THE DTC PARTICIPANT

     Please complete the questions below to ensure the Exchange Offer and the
tender of Old Notes is in compliance with state jurisdictional requirements.

Principle Place of Business or Domicile:
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Please check all of the following categories that are applicable to you:
[ ] financial institution or institutional buyer
[ ] broker-dealer
[ ] bank
[ ] savings institution
[ ] trust company
[ ] depository institution
[ ] insurance company
[ ] separate account of an insurance company
[ ] Investment Company as defined in the Investment Company Act of 1940
[ ] pension
[ ] profit-sharing trust
[ ] a small business investment company licensed by the federal small business
    administration under the federal "Small Business Investment Act of 1958"
[ ] a business development company as defined in the federal "Investment
    Advisers Act of 1940" [CCH Federal Securities Law Reporter par. 47, 300F]
[ ] a private business development company as defined in the federal "Investment
    Advisers Act of 1940" [CCH Federal Securities Law Reporter par. 56,347B]
[ ] an entity, but not an individual, a substantial part of whose business
    activities consist of investing, purchasing, selling or trading in
    securities of more than one issuer and not of its own issue and that has
    total assets in excess of five million dollars as of the end of its latest
    fiscal year;

[ ] a Qualified Institutional Buyer as defined in 17 C.F.R. 230.144A(a)


Name of Beneficial Owner(s):
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Signature(s): Name(s) (please print):
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Date:
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