Document:

<PAGE>   1
                                                                     EXHIBIT 4.5

                          INTERCREDITOR AND COLLATERAL
                                AGENCY AGREEMENT

                                      among

                       TRI-UNION DEVELOPMENT CORPORATION,
                          TRIBO PETROLEUM CORPORATION,
                           TRI-UNION OPERATING COMPANY
                                       AND
          EACH OF THE SUBSIDIARY GUARANTORS NOW OR HEREAFTER SIGNATORY
                                     HERETO,

          EACH OF THE APPROVED HEDGE COUNTERPARTIES OR HEDGE LIQUIDITY
                  PROVIDERS NOW OR HEREAFTER SIGNATORY HERETO,

                WELLS FARGO BANK MINNESOTA, NATIONAL ASSOCIATION,
                              as Collateral Agent,

                       FIRSTAR BANK, NATIONAL ASSOCIATION,
                                   as Trustee,

                            Dated as of June 18, 2001

<PAGE>   2

                                TABLE OF CONTENTS

<Table>
<S>                                                                                                              <C>
ARTICLE I DEFINITIONS.............................................................................................2
   Section 1.01     Indenture Definitions.........................................................................2
   Section 1.02     Other Definitions.............................................................................2
   Section 1.03     Headings......................................................................................5
   Section 1.04     Terms Generally...............................................................................5
ARTICLE II APPLICATION OF PROCEEDS................................................................................5
   Section 2.01     Election to Pursue Remedies...................................................................5
   Section 2.02     Duty of the Collateral Agent..................................................................7
   Section 2.03     Application of Proceeds.......................................................................8
   Section 2.04     Payments by Collateral Agent..................................................................9
   Section 2.05     Notices under Related Documents...............................................................9
   Section 2.06     Voting Procedure..............................................................................9
   Section 2.07     Triggering Event..............................................................................9
   Section 2.08     Pro Rata Treatment; Participations...........................................................10
   Section 2.09     Bankruptcy Preferences.......................................................................11
   Section 2.10     Marshaling...................................................................................11
   Section 2.11     Additional Parties...........................................................................11
   Section 2.12     Disposition of Proceeds......................................................................12
ARTICLE III COLLATERAL; CREDITORS................................................................................12
   Section 3.01     Status of Liens; Collateral..................................................................12
   Section 3.02     Possession, Use and Release of Collateral....................................................13
   Section 3.03     Deposit, Use and Release of Collateral Account Assets........................................17
   Section 3.04     Form and Sufficiency of Release..............................................................18
   Section 3.05     Purchaser Protected..........................................................................18
   Section 3.06     Authorization of Actions To Be Taken by the Trustee Under the Security Documents.............18
   Section 3.07     Authorization of Receipt of Funds by the Trustee Under the Security Documents................19
   Section 3.08     Property of Obligors.........................................................................19
   Section 3.09     Legends......................................................................................19
   Section 3.10     Creditor Dealings; Good Faith................................................................19
ARTICLE IV CALCULATION OF OBLIGATIONS............................................................................19
   Section 4.01     Notice of Amount of Obligations..............................................................19
ARTICLE V THE COLLATERAL AGENT...................................................................................19
   Section 5.01     Appointment of Collateral Agent..............................................................19
   Section 5.02     Nature of Duties of Collateral Agent.........................................................20
   Section 5.03     Lack of Reliance on the Collateral Agent.....................................................20
   Section 5.04     Certain Rights of the Collateral Agent.......................................................21
   Section 5.05     Reliance by Collateral Agent.................................................................21
   Section 5.06     Collateral Agent's Reimbursements and Indemnification........................................21
   Section 5.07     The Collateral Agent in its Individual Capacity..............................................22
   Section 5.08     Creditors as Owners..........................................................................22
   Section 5.09     Successor Collateral Agent...................................................................22
   Section 5.10     Employment of Collateral Agent and Counsel...................................................23
   Section 5.11     Limitation on Liability of the Creditors and Collateral Agent................................23
</Table>

                                      -i-
<PAGE>   3

<Table>
<S>                                                                                                              <C>
ARTICLE VI MISCELLANEOUS.........................................................................................23
   Section 6.01     Authority....................................................................................23
   Section 6.02     Termination/Withdrawal/Redesignation of Contracts............................................23
   Section 6.03     Amendments...................................................................................24
   Section 6.04     Notices, etc.................................................................................24
   SECTION 6.05     PAYMENT OF EXPENSES AND TAXES; INDEMNIFICATION...............................................25
   Section 6.06     Applicable Law...............................................................................27
   Section 6.07     Entire Agreement.............................................................................27
   Section 6.08     Execution in Counterparts....................................................................27
   Section 6.09     Severability.................................................................................27
   Section 6.10     Conflict with Security Documents.............................................................27
   Section 6.11     Limitation by Law............................................................................27
   Section 6.12     Benefit of Agreement; Limitation on Assignment...............................................27
   Section 6.13     Further Assurances, Recording and Opinions...................................................27
   Section 6.14     No Impairment................................................................................28
   Section 6.15     Status of Obligations........................................................................28
   Section 6.16     Counterclaims and Defenses by Obligors.......................................................29
</Table>

Annex 1 - Security Documents
Annex 2 - Supplemental Intercreditor and Collateral Agency Agreement (Obligors)
Annex 3 - Supplemental Intercreditor and Collateral Agency Agreement (Creditors)

                                      -ii-
<PAGE>   4

                  INTERCREDITOR AND COLLATERAL AGENCY AGREEMENT

         THIS INTERCREDITOR AND COLLATERAL AGENCY AGREEMENT (this "Agreement")
dated as of June 18, 2001, is among Tribo Petroleum Corporation, a Texas
corporation ("Tribo"), Tri-Union Development Corporation, a Texas corporation
(the "Company"), Tri-Union Operating Company, a Delaware corporation
("Operating"), each other Subsidiary Guarantor that hereafter executes a
Supplement hereto, the Approved Hedge Counterparties and Hedge Liquidity
Providers, Firstar Bank, National Association, as trustee under the Indenture
(the "Trustee"), and Wells Fargo Bank Minnesota, National Association, as
collateral agent hereunder (the "Collateral Agent").

                                    RECITALS

         A. On the date of this Agreement and in the future, the Obligors and
the Approved Hedge Counterparties will enter into the Approved Hedge Agreements;
and from time to time in the future, the Obligors may enter into certain
revolving credit or loan agreements or letter of credit reimbursement agreements
(each being a "Hedge Liquidity Agreement") with various financial institutions
(each being a "Hedge Liquidity Provider") to permit the Company or any of the
Restricted Subsidiaries to provide letters of credit as margin in lieu of the
Collateral to secure excess market exposure and settlement and related amounts
due on early termination under the Approved Hedge Agreements and the Security
Documents.

         B. On the date of this Agreement, the Company, as issuer, and the other
Obligors, as guarantors, and the Trustee, on behalf of, and for the benefit of,
the Holders, are entering into that certain Indenture (the "Indenture"),
pursuant to which, the Company will issue its 12.50% Senior Secured Notes due
2006 (the "Notes").

         C. To secure, inter alia, the Approved Hedge Counterparty Obligations,
the Hedge Liquidity Obligations, the Indenture Obligations and the Guaranty
Obligations (the Approved Hedge Agreements, the Hedge Liquidity Agreement, the
Indenture and the Guaranty Agreement collectively being the "Principal
Agreements") and the other obligations of the Obligors under the Security
Documents, the Obligors will execute and deliver the Security Documents pursuant
to the Principal Agreements.

         D. The Approved Hedge Counterparties, each Hedge Liquidity Provider,
the Trustee (for itself and on behalf of the Holders), the Holders (all such
Persons, for so long as a Party to this Agreement, collectively being the
"Creditors"), and the Collateral Agent are entering into this Agreement to
establish their relative rights with respect to payment of their respective
Obligations owed by the Obligors, to agree as to the exercise of certain
remedies and to appoint a Collateral Agent for the purposes of dealing with the
Security Documents and apportioning payments among the Creditors and for other
purposes as set forth herein.

         E. NOW, THEREFORE, for good and valuable consideration, the receipt and
sufficiency of which are hereby acknowledged, the parties hereto hereby agree as
follows:

<PAGE>   5

                                    ARTICLE I
                                   DEFINITIONS

         Section 1.01 Indenture Definitions. Each capitalized term used, but not
defined herein, shall have the meaning ascribed such term in the Indenture.

         Section 1.02 Other Definitions. The terms defined in the recitals shall
have the meanings assigned to those terms in such recitals, and the following
terms shall have the meanings assigned as follows:

         "Approved Hedge Agreement" means (A) any Oil and Gas Hedging Contract
with Bank of America, N.A., and (B) any Oil and Gas Hedging Contract with any
other Approved Hedge Counterparty (i) which designates in the confirmation or
other transaction statement pursuant to which such Oil and Gas Hedging Contract
is evidenced that it is an "Approved Hedge Agreement" for purposes of the
Intercreditor Agreement, the Indenture and the Security Documents and (ii) a
copy of which has been delivered to the Collateral Agent and the Trustee, in
case of either (A) or (B) until (a) the Approved Hedge Counterparty ceases to be
an Approved Hedge Counterparty under the Intercreditor Agreement or (b) the
Approved Hedge Counterparty specifies in writing to the Collateral Agent, the
Trustee and the Company that such contract ceased to be an Approved Hedge
Agreement, and (C) any Oil and Gas Hedging Contract that is a price floor,
option for a price floor or other similar arrangement for which, upon entering
into such contract, neither Tribo nor any Restricted Subsidiary will have any
liability other than the payment of an initial premium price.

         "Approved Hedge Counterparties" means (A) Bank of America, N.A., unless
it has ceased to be an Approved Hedge Counterparty, (B) any other Person that
(i) executes an Oil and Gas Hedging Contract with the Company or a Restricted
Subsidiary, (ii) has, or receives credit support in the form of an unconditional
guarantee of payment from a parent who has a long-term unsecured senior debt
rating of at least BBB- by Standard & Poor's Rating Service or Baa3 by Moody's
Investors Service, Inc., (iii) is designated as such by the Company in writing
to the Trustee and the Collateral Agent and (iv) if no Hedge Liquidity Provider
is then (or thereafter) providing letters of credit as collateral for the
Hedging Obligations owed to such Person, or such Person has not otherwise ceased
to be an Approved Hedge Counterparty, executes and delivers to the Collateral
Agent and the Trustee a supplement to the Intercreditor Agreement, and (C) for
purposes of the provisions of Section 4.25 of the Indenture only and the
definition of "Hedged Revenues", only the Persons in clauses (A) and (B) above
and any Person who meets the requirement set forth in subclause (B)(ii) above
and who enters into any Oil and Gas Hedging Contract with the Company or a
Restricted Subsidiary that is a price floor, option for a price floor or other
similar arrangement for which, upon entering into such contract, neither the
Company nor any Restricted Subsidiary will have any liability other than the
payment of an initial premium price.

         "Approved Hedge Counterparty Obligations" means all obligations of the
Obligors under all Approved Hedge Agreements, including all unpaid amounts,
settlement amounts, indemnities, costs, expenses (including reasonable
attorneys' fees), interest on past due amounts and other liabilities and
obligations then due and unpaid by the Company or any other Obligor.

         "Collateral" means the properties and rights described in the Security
Documents as security for any of the Obligations.

                                      -2-
<PAGE>   6

         "Collateral Account" shall have the meaning set forth in Section 3.03.

         "Collateral Account Assets" means all financial assets from time to
time held in or credited to the Collateral Account.

         "Disgorged Amount" shall have the meaning set forth in Section 2.09.

         "Disgorged Creditor" shall have the meaning set forth in Section 2.09.

         "Environmental Laws" means any and all Governmental Requirements
pertaining to health or the environment in effect in any and all jurisdictions
in which the Mortgagor or any of its Subsidiaries is conducting or at any time
has conducted business, or where any property of the Mortgagor or any of its
Subsidiaries is located, including without limitation, the Oil Pollution Act of
1990 ("OPA"), the Clean Air Act, as amended, CERCLA, the Federal Water Pollution
Control Act, as amended, the Occupational Safety and Health Act of 1970, as
amended, the Resource Conservation and Recovery Act of 1976, as amended
("RCRA"), the Safe Drinking Water Act, as amended, the Toxic Substances Control
Act, as amended, the Superfund Amendments and Reauthorization Act of 1986, as
amended, the Hazardous Materials Transportation Act, as amended, and other
environmental conservation or protection laws. The term "oil" shall have the
meaning specified in OPA, the terms "hazardous substance" and "release" (or
"threatened release") have the meanings specified in CERCLA, and the terms
"solid waste" and "disposal" (or "disposed") have the meanings specified in
RCRA; provided, however, that (i) in the event either OPA, CERCLA or RCRA is
amended so as to broaden the meaning of any term defined thereby, such broader
meaning shall apply subsequent to the effective date of such amendment, (ii) to
the extent the laws of the state in which any property of the Mortgagor or any
of its Subsidiaries is located establish a meaning for "oil," "hazardous
substance," "release," "solid waste" or "disposal" which is broader than that
specified in either OPA, CERCLA or RCRA, such broader meaning shall apply, and
(iii) the terms "hazardous substance" and "solid waste" shall include all oil
and gas exploration and production wastes that may present an endangerment to
public health or welfare or the environment, even if such wastes are
specifically exempt from classification as hazardous substances or solid wastes
pursuant to CERCLA or RCRA or the state analogues to those statutes.

         "Guaranty Agreement" means that certain Guaranty Agreement dated of
even date herewith in favor of the Trustee, each Approved Hedge Counterparty
which is a party to this Agreement, each Hedge Liquidity Provider which is a
party to this Agreement, and each Holder.

         "Guaranty Obligations" means the "Liabilities" as such term is defined
in the Guaranty Agreement.

         "Hedge Liquidity Obligations" means all obligations of the Obligors
under all Hedge Liquidity Agreements, including all amounts drawn under letters
of credit issued thereunder and all indemnities, costs, expenses (including
reasonable attorneys' fees), interest and other liabilities and obligations
thereunder then due and unpaid by the Company or any other Obligor.

                                      -3-
<PAGE>   7

         "Indenture Obligations" means the "Obligations" as such term is defined
in the Indenture.

         "Obligations" means all Indenture Obligations, Guaranty Obligations,
Approved Hedge Counterparty Obligations and, if a Hedge Liquidity Agreement is
in place, all Hedge Liquidity Obligations, including, but not limited to, all
other sums of money which may be hereafter paid or advanced by any Creditor
under the terms and provisions of this Agreement, any Principal Agreement or the
other Security Documents as such sums of money relate either to the
administration, protection and exercise of remedies in connection with this
Agreement, any Principal Agreement or the Security Documents, or to any
reimbursement and indemnity provisions contained in this Agreement, any
Principal Agreement and the Security Documents.

         "Obligor" means the Company, Tribo, Operating and each other Subsidiary
Guarantor that hereafter becomes a party hereto.

         "Officers' Certificate" means an Officers' Certificate as defined in
the Indenture that is addressed to the Approved Hedge Counterparties or Hedge
Liquidity Provider, as appropriate, the Collateral Agent and the Trustee.

         "Pledge and Collateral Account Agreement" means either (i) that certain
Pledge and Collateral Account Agreement dated of even date herewith among the
Company, Wells Fargo Bank Minnesota, National Association, as securities
intermediary, and the Collateral Agent, or (ii) such other agreement or
agreements entered into by the Company and the Collateral Agent to create
accounts and grant in favor of the Collateral Agent, for the ratable benefit of
the Creditors, a valid and perfected, first priority Lien on all assets
deposited therein and which is subject to the exclusive control and dominion of
the Collateral Agent.

         "Principal Agreements" has the meaning specified in Recital C.

         "Proceeds" means all cash proceeds and other Property received by the
Collateral Agent, any Approved Hedge Counterparty, any Hedge Liquidity Provider
or the Trustee from or for the account of any Obligor, from or with respect to
Principal Agreements, the Security Documents or the Collateral.

         "Pro Rata Share" means as to any Creditor, an amount equal to a
fraction, (a) the numerator of which is (i) the Indenture Obligations, (ii) the
net amount of the Approved Hedge Counterparty Obligations or (iii) all Hedge
Liquidity Obligations, in each case, owed to such Creditor and (b) the
denominator of which is the sum of (i) all Indenture Obligations, (ii) the net
amount of all Approved Hedge Counterparty Obligations and (iii) all Hedge
Liquidity Obligations.

         "Receivables Proceeds" means whatever property is acquired upon the
disposition of an Account Receivable.

         "Required Creditors" means any of the following: (i) each of the
Approved Hedge Counterparties then a party hereto, (ii) Hedge Liquidity
Providers holding greater than 50% of aggregate commitments of the Hedge
Liquidity Providers under the Hedge Liquidity Agreement or their designated
representative and (iii) the Trustee.

                                      -4-
<PAGE>   8

         "Security Documents" means the documents set forth on Annex 1 as such.

         "TIA" means the Trust Indenture Act of 1939 (15 U.S.C. Sections
77aaa-77bbbb) as in effect from time to time.

         "Transaction Documents" means this Agreement, the Principal Agreements
and the Security Documents.

         "Triggering Event" shall have the meaning set forth in Section 2.07.

         "Uniform Commercial Code" means the Uniform Commercial Code as in
effect from time to time in the State of New York.

         Section 1.03 Headings. Article and section headings of this Agreement
are for convenience of reference only, and shall not govern the interpretation
of any of the provisions of this Agreement.

         Section 1.04 Terms Generally. The definitions of terms herein shall
apply equally to the singular and plural forms of the terms defined. Whenever
the context may require, any pronoun shall include the corresponding masculine,
feminine and neuter forms. The words "include", "includes" and "including" shall
be deemed to be followed by the phrase "without limitation". The word "will"
shall be construed to have the same meaning and effect as the word "shall".
Unless the context requires otherwise (a) any definition of or reference to any
agreement, instrument or other document herein shall be construed as referring
to such agreement, instrument or other document as from time to time amended,
supplemented, renewed, replaced, increased, restated or otherwise modified
(subject to any restrictions on such amendments, supplements or modifications
set forth herein), (b) any reference herein to any Person shall be construed to
include such Person's successors and assigns, provided such successors and
assigns are permitted by the Principal Agreement to which such Person is a party
and such Person complies with Section 6.12 hereof, (c) the words "herein",
"hereof" and "hereunder", and words of similar import, shall be construed to
refer to this Agreement in its entirety and not to any particular provision
hereof, (d) all references herein to Articles, Sections, Exhibits and Schedules
shall be construed to refer to Articles and Sections of, and Exhibits and
Schedules to, this Agreement unless otherwise indicated and (e) the words
"asset" and "property" shall be construed to have the same meaning and effect
and to refer to any and all tangible and intangible assets and properties,
including cash, securities, accounts, contract rights and general intangibles.

                                  ARTICLE II
                            APPLICATION OF PROCEEDS

         Section 2.01 Election to Pursue Remedies.

         (a) The amounts payable by the Obligors to each Creditor at any time
under any of the Principal Agreements to which such Creditor is a party shall be
separate and independent debts, and each Creditor shall be entitled to enforce
any right arising out of the applicable Principal Agreement to which it is a
party, including the Guaranty Agreement, subject to the terms thereof and of
this Agreement. Each Creditor hereby agrees that no Creditor other than the
Collateral Agent (in its

                                      -5-
<PAGE>   9

capacity as such) shall have any right individually to realize upon any Liens
granted under the Security Documents, it being understood and agreed that such
remedies may be exercised only by the Collateral Agent for the ratable benefit
of the Creditors.

         (b) Upon the occurrence and during the continuance of any Triggering
Event, the Collateral Agent shall, upon the request of any Required Creditors
and subject to this Section 2.01, Section 2.02 and Article IV, take or, as
appropriate, direct the appropriate trustee or agent to take, any and all
actions provided for in the Security Documents relating to the pursuit of
remedies, including the foreclosure or disposition of Collateral.

         (c) Upon the occurrence and during the continuance of any Triggering
Event, any of the Approved Hedge Counterparties, the Hedge Liquidity Providers
or the Trustee (as used in this Section 2.01, the "Directing Creditor") shall
have the right to direct the Collateral Agent to pursue any remedy or remedies
available to the Collateral Agent at law, under any Security Document or
otherwise, provided, however, that

                  (i) any direction shall: (A) include written instructions
         specifying the particular action to be taken, (B) indemnify the
         Collateral Agent as contemplated by Section 5.04, and (C) be sent to
         each other Creditor (or their representative, i.e., the Trustee in the
         case of the Holders);

                  (ii) if requested within 5 Business Days by any other Creditor
         or group of Creditors (with a copy to the Collateral Agent which shall
         cease to comply with the previous direction until further notice), the
         Directing Creditor shall meet with such other Creditor or group of
         Creditors to discuss and identify which Collateral may be foreclosed
         upon or disposed of, the order of sale and such other decisions as may
         be relevant in order to maximize the amounts received in respect of the
         Collateral to be foreclosed on or disposed of and to maximize the value
         of the remaining Collateral (provided that if such parties fail to
         reach any consensus, the direction previously given the Collateral
         Agent shall not be impaired and the Collateral Agent shall receive
         notice directing it to proceed as previously instructed); and

                  (iii) the Collateral Agent shall cease to comply with any such
         direction if jointly instructed to do so in writing by such Directing
         Creditor and the Company on the basis that (A) such Triggering Event
         has been cured or waived, (B) the amounts owed by the Obligors to such
         Directing Creditor have been otherwise paid in full or otherwise
         discharged and, if such Directing Creditor was at the time of giving
         such direction an Approved Hedge Counterparty, either (1) the Directing
         Creditor is no longer an "Approved Hedge Counterparty" (and hence a
         "Creditor" hereunder) or (2) the Approved Hedge Agreement in respect of
         which such amount is owed is no longer an Approved Hedge Agreement. No
         Creditor or group of Creditors shall have the right to overrule or
         override any directions given by an Approved Hedge Counterparty to the
         Collateral Agent pursuant to this Section.

Upon receipt by the Collateral Agent of such instructions, the Collateral Agent
shall immediately commence to take or direct the instructed actions (and
continue to take such actions) relating such remedies.

                                      -6-
<PAGE>   10

         (d) Without regard to the occurrence of a Triggering Event, upon the
written instruction of any Directing Creditor, with indemnities appropriate for
such instructions as provided in Section 5.04, the Collateral Agent shall (i)
take or direct any action provided for in the Security Documents (other than
foreclosure or disposition of the Collateral) or proceed to enforce, or direct
the enforcement of, consistent with the Security Documents and applicable law
(other than foreclosure or disposition of the Collateral), the rights or powers
provided in the Security Documents and under applicable law for the benefit of
the Creditors and shall give such notice or direction or shall take such action
or exercise such right or power hereunder or under any of the Security Documents
incidental thereto as shall be reasonably specified in such instructions and
consistent with the terms of the Security Documents and this Agreement; and/or
(ii) execute such instruments or agreements or take such other action in
connection with the Security Documents as may be reasonably requested by such
Directing Creditor and consistent with the terms of the Security Documents and
this Agreement. Such action may include, but is not limited to (x) the giving of
any release, notice, approval, consent or waiver which may be called for
hereunder or under the Security Documents that the Collateral Agent is expressly
authorized to give, (y) the requiring of the execution and delivery of
additional Security Documents, or (z) employing agents or directing trustees in
order to accomplish the actions requested.

         (e) If a Triggering Event is continuing and no instructions have been
delivered pursuant to Section 2.01(c), then the Collateral Agent shall take such
action as it shall deem reasonable to protect the interests of the Creditors or
as necessary to comply with any obligations imposed under any applicable law,
including, without limitation, the TIA.

         (f) Nothing in this Section 2.01 shall impair the right of any Creditor
to exercise its rights of set-off or netting, if any. Nothing shall impair the
ability of the Trustee to take any action necessary to comply with any
obligations imposed under any applicable law, including, without limitation, the
TIA.

         Section 2.02 Duty of the Collateral Agent.

         (a) The Collateral Agent shall not be obligated to follow any
instructions of any one or more of the Creditors if: (i) such instructions
conflict with the provisions of this Agreement, any Principal Agreement, any
Security Document or any applicable law, (ii) the Collateral Agent determines,
in its sole and absolute discretion, that such instructions are ambiguous,
inconsistent, in conflict with previously received instructions or otherwise
insufficient to direct the actions of the Collateral Agent, provided that the
Collateral Agent explains the grounds for a refusal based on a deficiency of
instructions to the requesting party, or (iii) the Collateral Agent has not been
adequately indemnified to its satisfaction. Nothing in this Article II shall
impair the right of the Collateral Agent in its discretion to take any action
authorized under this Agreement or the Security Documents, to the extent that
the consent of any of the Creditors is not required or to the extent such action
is not prohibited by the terms hereof or thereof, which it deems proper and
consistent with the instructions given by the Creditors as provided for herein
or otherwise in the best interest of the Creditors. In the absence of written
instructions from any Required Creditor for any particular matter, the
Collateral Agent shall have no duty to take or refrain from taking any action
unless such action or inaction is explicitly required by the terms of this
Agreement, a Security Document or applicable law, including, without limitation,
the TIA. The Collateral Agent shall have no duty with respect to a Triggering

                                      -7-
<PAGE>   11

Event under any Security Document unless it first receives notice that a
Triggering Event has occurred.

         (b) Beyond its duties expressly provided herein or in any Security
Document and its duties to account to the Creditors and/or the Obligors for
monies and other property received by it hereunder or under any Security
Document, the Collateral Agent shall have no implied duty to the Creditors or
any Obligor as to any property belonging to an Obligor (whether or not the same
constitutes Collateral) in its possession or control or in the possession or
control of any of its agents or nominees, or any income thereon or as to the
preservation of rights against prior parties or any other rights pertaining
thereto.

         Section 2.03 Application of Proceeds. Upon the occurrence and during
the continuance of a Triggering Event, all Proceeds received by the Collateral
Agent from any Obligor or any Creditor under Section 2.08, including all
realizations from Collateral and Proceeds thereof and whether or not all
obligations of the Creditors are cross-collateralized (net of the costs and
expenses reasonably incurred in connection therewith and any taxes, assessments
or prior Liens) shall be applied promptly by the Collateral Agent in the
following order of priority:

                  (i) FIRST: to the payment and reimbursement of all fees,
         expenses and indemnities owed to the Collateral Agent (including the
         reasonable legal fees and expenses of its agents and counsel) pursuant
         to this Agreement and the Security Documents;

                  (ii) SECOND: to the payment to (1) Approved Hedge
         Counterparties under Approved Hedge Agreements for which an early
         termination date has been designated of (A) the net amount due such
         Approved Hedge Counterparty under all such terminated Approved Hedge
         Agreements to which it was a party (whether as settlement amounts or
         unpaid amounts) and (B) all accrued and unpaid interest thereon and all
         fees, expenses, cash collateralization amounts, indemnities and other
         amounts owed to such Approved Hedge Counterparty thereunder or in
         respect thereof, (2) Approved Hedge Counterparties of regularly
         scheduled payments under Approved Hedge Agreements for which no early
         termination date has been designated or (3) Hedge Liquidity Providers
         and their agent(s) or representative(s), if any, all cash
         collateralization amounts, principal, interest, fees, expenses and
         indemnities owed to such Hedge Liquidity Providers under their Hedge
         Liquidity Agreement; provided that if such monies shall not be
         sufficient to pay in full the entire amount then outstanding, then to
         make pro rata payments among clauses (1) - (3), without any preference
         or priority, to all such Approved Hedge Counterparties or Hedge
         Liquidity Providers, as applicable;

                  (iii) THIRD: to the payment and reimbursement of all fees,
         expenses and indemnities owed to the Trustee under or provided for
         under the Indenture;

                  (iv) FOURTH: to the payment of accrued and unpaid interest on
         the Notes payable under the Indenture, and if such monies shall not be
         sufficient to pay in full the entire amount then outstanding, then to
         make pro rata payments, without any preference or priority, to each
         Holder;

                                      -8-
<PAGE>   12

                  (v) FIFTH: to the ratable payment of the outstanding principal
         balance of the Notes (including any premium then due); and if such
         monies shall not be sufficient to pay in full the entire amount then
         outstanding, then to make pro rata payments, without any preference or
         priority, to each Holder;

                  (vi) SIXTH: to the Collateral Agent to hold as cash collateral
         to make payments or deposits due under the Principal Agreements until
         such time as it determines that all such obligations have been paid in
         full or pay any other amounts which may be then due and owing
         thereunder or under any Security Document; and

                  (vii) FINALLY: to the payment of the remainder, if any, to the
         Company or as a court of competent jurisdiction may otherwise direct.

         Section 2.04 Payments by Collateral Agent. All payments hereunder by
the Collateral Agent to the Trustee shall be for distribution in the manner set
forth in the Indenture. In the event any other payment is due to a group of
Creditors under a Principal Agreement to which they are a party, the Collateral
Agent shall make such payment to their representative for distribution by it in
accordance with the terms of such Principal Agreement.

         Section 2.05 Notices under Related Documents.

         (a) Each Creditor agrees: (i) to deliver to the Collateral Agent, at
the same time it makes delivery to the Obligors, a copy of any notice of
default, notice of intent to accelerate or notice of acceleration with respect
to any of the Obligations subject to this Agreement; and (ii) to deliver to the
Collateral Agent, at the same time it makes delivery to any other Person, a copy
of any notice of the commencement of any judicial proceeding and a copy of any
other notice with respect to the exercise of remedies with respect to the
Obligations subject to this Agreement.

         (b) The Collateral Agent shall deliver to each Creditor (or their
designated representative if a group) promptly upon receipt thereof (and in any
event within two Business Days), duplicates or copies of any notice received by
it under Section 2.05(a) and all notices, requests and other instruments
received by the Collateral Agent under or pursuant to this Agreement or any
Security Document, to the extent that the same shall not have been previously
furnished to such Creditor pursuant hereto or thereto.

         Section 2.06 Voting Procedure. When this Agreement or any Security
Document requires or permits a vote of the Required Creditors, the Collateral
Agent shall poll each of the Approved Hedge Counterparties, the Hedge Liquidity
Provider(s) (or their designated representative(s)), if any, and the Trustee in
order to determine the vote of the Required Creditors (and such vote shall be
binding upon the Creditors who are not among the Required Creditors). The
Obligors and the Creditors may rely on the Collateral Agent with regard to any
such vote without any duty of further inquiry.

         Section 2.07 Triggering Event. The occurrence of any of the following
shall constitute a "Triggering Event":

                                      -9-
<PAGE>   13

         (a) The occurrence and continuance of an event of default under clauses
(i) and (j) of Section 6.01 of the Indenture or any similar provision(s) in any
Approved Hedge Agreement or Hedge Liquidity Agreement; or

         (b) The Collateral Agent shall have received from any Approved Hedge
Counterparty written notice, which notice shall reference this Section 2.07, (i)
that either an event of default or a termination event has occurred and is
continuing under one or more of its Approved Hedge Agreements, (ii) that an
early termination date has been designated as a result thereof, (iii) that
specifies the sum of all unpaid amounts and settlement payments then due as the
result of the designation of such early termination date and the amount of
interest and other amounts then due and payable by the Obligors in respect
thereof, and (iv) that the amount set forth in clause (iii) has not been paid in
full or discharged to the satisfaction of such Approved Hedge Counterparty; or

         (c) The Collateral Agent shall have received from the Trustee or the
Holders of at least 25% of the outstanding principal amount of the Notes, as
appropriate, written notice, which notice shall reference this Section 2.07, (i)
that an "Event of Default" under the Indenture has occurred and is continuing
and (ii) that the unpaid principal amount of the Notes and all interest accrued
and unpaid thereon have been declared to be then due and payable; or

         (d) The Collateral Agent shall have received from one or more Hedge
Liquidity Providers (or their representative) of greater than 50% of the face
amounts of all letters of credit issued under any Hedge Liquidity Agreement,
written notice, which notice shall reference this Section 2.07, (i) that an
"Event of Default" under such Hedge Liquidity Agreement has occurred and is
continuing and (ii) that the unpaid amount owed in respect of the letters of
credit and all interest accrued and unpaid thereon have been declared to be then
due and payable.

         Section 2.08 Pro Rata Treatment; Participations. The Creditors hereby
agree among themselves that (a) prior to the occurrence and continuance of a
Triggering Event, each Creditor shall be entitled to receive and retain for its
own account, and shall never be required to disgorge to the Collateral Agent or
any other Creditor hereunder or acquire direct or participating interests in
such Creditor's Obligations, scheduled payments or voluntary prepayments,
payments for the redemption or purchase of principal, interest, fees and
premium, if any, settlement payments and any other payments in respect of the
Principal Agreements, all in compliance with the terms thereof, and (b) after
the occurrence and during the continuance of a Triggering Event, all Proceeds
shall be applied by the Collateral Agent and shared by the Creditors in
accordance with the respective Pro Rata Share held by each of them and in
accordance with Section 2.03. In the event that any Creditor shall obtain
payment after the occurrence and during the continuance of a Triggering Event,
whether in whole or in part, from any source (other than (a) payments made by
the Collateral Agent in accordance with Section 2.03 or (b) the exercise by
Approved Hedge Counterparties of netting or offset rights under Approved Hedge
Agreements) in respect of its portion of the Obligations, including, without
limitation, payments by reason of the exercise of its right of offset, banker's
lien, general lien or counterclaim or otherwise through the exercise of any
remedy or any other effort to collect amounts due from any Obligor, such
Creditor shall (i) promptly notify the Collateral Agent (which may conclusively
rely on such notice) and (ii) purchase for cash from such other Creditor(s)
holding a priority claim a participation in such Obligations held by such other
Creditor(s) having a priority claim in the priority set forth in Section 2.03.
Each Obligor expressly consents to the

                                      -10-
<PAGE>   14

foregoing arrangements and agrees that any Creditor holding such a participation
may exercise any and all rights of banker's lien, setoff or counterclaim with
respect to any and all moneys owing by any Obligor to such Creditor as fully as
if such Creditor had made a loan directly to such Obligor in the amount of such
participation.

         Section 2.09 Bankruptcy Preferences. If any payment actually received
by any Creditor is subsequently invalidated, declared to be fraudulent or
preferential or set aside and is required to be repaid to a trustee, receiver or
any other party under any bankruptcy law, state or Federal law, common law or
equitable cause (any such amount required to be repaid being a "Disgorged
Amount"), then such Creditor (the "Disgorged Creditor") shall have a claim under
Section 2.03 in an amount equal to the Disgorged Amount, and the Collateral
Agent shall pay the Disgorged Amount to such Disgorged Creditor in the order of
priority set forth in Section 2.03 as if payment in respect of such Disgorged
Amount had never been made by the Collateral Agent to such Disgorged Creditor
hereunder; provided, however, that any amounts payable by the Collateral Agent
to a Disgorged Creditor pursuant to this Section 2.09 shall be payable solely
from Proceeds, if any, and no Creditor shall acquire direct or participating
interests in such Disgorged Creditor's Obligations or be required to pay to the
Collateral Agent, a Disgorged Creditor or any other Person any amounts in
respect of any Disgorged Amounts. If this Agreement or the Security Documents
have terminated and any payment actually received by any Creditor is
subsequently invalidated, rescinded, declared to be fraudulent or preferential
or set aside and is required to be repaid under any bankruptcy or other similar
law, then this Agreement and the Security Documents shall be reinstated and
their provisions will continue in effect for the benefit of such Creditor until
such amounts are fully and finally paid in cash.

         Section 2.10 Marshaling. The Collateral Agent shall not be required to
marshal any present or future security (including without limitation any
Collateral described in any of the Security Documents), or guaranties of the
Obligations or any part or portion thereof, or to resort to such Collateral or
guaranties in any particular order; and all rights in respect of such Collateral
and guaranties shall be cumulative and in addition to all other rights, however
existing or arising. To the extent that they lawfully may, each Obligor hereby
agrees that it will not invoke any law relating to the marshaling of Collateral
which might cause delay or impede the enforcement of the Creditors' rights under
any Principal Agreement or the Security Documents or under any other instrument
evidencing any of the Obligations or under which any of the Obligations is
outstanding or by which any of the Obligations is secured or guaranteed.

         Section 2.11 Additional Parties. If any Person shall become an Obligor
under any of the Principal Agreements, the Company covenants and agrees to
promptly cause such Person to become a party hereto by executing and delivering
to the Collateral Agent a Supplement in the form of Annex 2 hereto. If any
Person desires to become an "Approved Hedge Counterparty" or a "Hedge Liquidity
Provider" for purposes of this Agreement and the Security Documents, then it
shall become a party hereto by delivering any documents required by the
definitions of Approved Hedge Agreement and Approved Hedge Counterparties and by
promptly executing and delivering to the Collateral Agent and the Trustee a
supplement in the form of Annex 3 hereto. In each case, upon such execution and
delivery, such Person shall be deemed a party hereto as if an original
signatory. Supplements executed pursuant to this Section 2.11 do not require the
signatures of all Creditors party to this Agreement.

                                      -11-
<PAGE>   15

         Section 2.12 Disposition of Proceeds. The Security Documents contain an
assignment by the Obligors unto and in favor of the Collateral Agent for the
benefit of the Creditors of all production and all proceeds attributable thereto
which may be produced from or allocated to the Collateral. The Security
Documents further provide in general for the application of such proceeds to the
satisfaction of the Obligations described herein and secured thereby.
Notwithstanding the assignment contained in such Security Documents, until the
occurrence of a Triggering Event, the Collateral Agent and the Creditors agree
that they will (i) neither notify the purchaser or purchasers of such production
nor take any other action to cause such proceeds to be remitted to the
Collateral Agent and the Creditors, but the Collateral Agent and the Creditors
will instead permit such proceeds to be paid to the relevant Obligor and (ii)
instruct the Collateral Agent to take (and the Collateral Agent shall take) such
action as may be requested by the Company to cause such proceeds to be so paid
to the Company.

                                   ARTICLE III
                              COLLATERAL; CREDITORS

         Section 3.01 Status of Liens; Collateral.

         (a) Each Creditor agrees that, subject to Section 2.03 and
notwithstanding anything to the contrary contained in any Security Document, (i)
all Creditors shall rank pari passu in priority with respect to any Lien on any
Collateral securing the Obligations, and (ii) all Liens on any Collateral
securing any Obligations shall rank pari passu with one another. Notwithstanding
anything else provided herein or in the Security Documents, except as
specifically requested in writing by the Creditors (in the case of the Holders,
the Trustee on their behalf), the Collateral Agent shall have no obligation or
liability in respect of the recording, re-recording, filing or refilling of any
instruments, documents, financing statements or continuation statements or to
take any other action hereunder with respect to the security interests created
hereby or pursuant to the Security Documents, and the Collateral Agent shall
have no obligation to monitor the status of the security interests as a
perfected security interest created hereunder or under the Security Documents
other than as set forth in legal opinions delivered to the Collateral Agent
pursuant to Section 6.13.

         (b) Each Creditor agrees that if such Creditor takes any additional
Collateral in respect of any Obligations, such Creditor shall take any and all
action necessary to create and perfect Liens on any such Collateral in favor of
the other Creditors for the equal and ratable benefit of all Creditors (subject
to Section 2.03), including, without limitation, executing and delivering
mortgages, security agreements, financing statements, amendments to financing
statements, and any other agreements, documents, certificates or instruments
necessary to accomplish the foregoing.

         (c) Each Creditor agrees to take any and all action necessary to cause
the Collateral Agent to be designated as the sole secured party in respect of
any Lien on any Collateral securing the Obligations, including, without
limitation, executing and delivering mortgages, security agreements, financing
statements, amendments to financing statements, and any other agreements,
documents, certificates or instruments evidencing or required or permitted to be
filed to create or perfect a Lien on Collateral.

                                      -12-
<PAGE>   16

         (d) Each Creditor and each Obligor will from time to time sign,
execute, deliver and file, alone or with the Collateral Agent or any other
Creditor or any other Obligor, and hereby authorizes the Collateral Agent to
file, any financing statements, security agreements, documents, certificates or
instruments pertaining to the Collateral, or any part thereof; procure any
agreements, documents, certificates or instruments as may be requested by the
Collateral Agent; and take all further action that may be necessary or
desirable, or that the Collateral Agent may reasonably request, to confirm,
perfect, preserve and protect the security interests intended to be granted
under the Security Documents, and in addition, each of the Creditors and the
Obligors hereby authorizes the Collateral Agent to execute and deliver on behalf
of such Person and to file such other financing statements, security agreements
and other agreements, documents, certificates or instruments without the
signature of such Person either in the Collateral Agent's name or in the name of
such Person and as agent and attorney-in-fact for such Person. Each Creditor and
each Obligor shall do all such additional and further acts or things, give such
assurances and execute such agreements, documents, certificates or instruments
as the Collateral Agent requires to vest more completely in and assure to the
Collateral Agent and the Creditors their rights under this Agreement (including
this Section 3.01), including, without limiting the generality of the foregoing,
marking conspicuously each note or other instrument evidencing the Obligations
with the legend described in Section 3.09 and, at the request of the Collateral
Agent, each of its records pertaining to the Collateral with such legend.

         Section 3.02 Possession, Use and Release of Collateral.

         (a) Unless an "Event of Default" or "Termination Event" under any
Principal Agreement shall have occurred and be continuing, Tribo and the
Restricted Subsidiaries will have the right to remain in possession and retain
exclusive control of the Collateral securing the Obligations (other than any
cash, securities, obligations and Temporary Cash Investments constituting part
of the Collateral and deposited with the Collateral Agent in the Collateral
Account and other than as set forth in the Security Documents), to freely
operate the Collateral and to collect, invest and dispose of any income thereon
or therefrom.

         (b) Upon compliance by Tribo and the Restricted Subsidiaries with the
conditions set forth below in respect of any sale, lease, transfer or other
disposition to any Person involving Collateral (including the disposition of all
of the Capital Stock of a Subsidiary Guarantor), the Collateral Agent will
release the Released Interests (as defined below) from the Lien of the Security
Documents and reconvey the Released Interests to Tribo or the relevant
Restricted Subsidiary or such other Person as Tribo or the Restricted Subsidiary
may direct in writing. Tribo and the Restricted Subsidiaries will have the right
to obtain a release of items of Collateral subject to any sale, lease, transfer
or other disposition or owned by a Subsidiary Guarantor all of the Capital Stock
of which is subject of a disposition (the "Released Interests") upon compliance
with the condition that the Company deliver to the Collateral Agent the
following:

                  (i) a notice from the Company requesting the release of
         Released Interests:

                           (A) describing the proposed Released Interests; and

                           (B) specifying the value, as reasonably determined by
                  the Company, of such Released Interests on a date within 60
                  days of the Company notice (the "Valuation Date"); and

                                     -13-
<PAGE>   17

                           (C) stating that the purchase price or other property
                  to be received in consideration for such Released Interests is
                  at least equal to the fair market value of the Released
                  Interests; and

                           (D) stating that the release of such Released
                  Interests will not interfere with the Collateral Agent's
                  ability to materially realize the value of the remaining
                  Collateral and will not materially impair the maintenance and
                  operation of the remaining Collateral; and

                           (E) confirming the sale, lease, transfer or other
                  disposition of, or an agreement to sell, lease, transfer or
                  dispose of, such Released Interests in a bona fide transaction
                  to a Person that is not an Affiliate of Tribo or, in the event
                  that such disposition is to a Person that is an Affiliate,
                  confirming that such disposition is made in compliance with
                  the provisions set forth in Section 4.11 of the Indenture, to
                  the extent applicable; and

                           (F) in the event there is to be a substitution of
                  property for the Collateral subject to the sale, lease,
                  transfer or other disposition, specifying the property
                  intended to be substituted for the Collateral to be disposed
                  of;

                           (G) attaching the form of release (the "Release")
                  requested by the Company to be executed by the Collateral
                  Agent;

                  (ii) an Officers' Certificate stating that:

                           (A) such sale, lease, transfer or other disposition
                  complies with the terms and conditions of any Hedge Liquidity
                  Agreement, Approved Hedge Agreements and Section 4.10 and
                  Section 4.07 of the Indenture, to the extent applicable; and

                           (B) all Net Available Cash from such sale, lease,
                  transfer or other disposition will be applied pursuant to any
                  Hedge Liquidity Agreement, Approved Hedge Agreements and
                  Section 4.10 of the Indenture, to the extent applicable; and

                           (C) there is no "Event of Default," "Triggering
                  Event" or "Termination Event" under any of the Principal
                  Agreements or this Agreement that is in effect or continuing
                  on the date thereof or the date of such sale, lease, transfer
                  or other disposition; and

                           (D) the release of the Collateral by the execution of
                  the Release will not result in an "Event of Default,"
                  "Triggering Event" or "Termination Event" under any of the
                  Principal Agreements or this Agreement; and

                           (E) upon the delivery of such Officers' Certificate,
                  all conditions precedent in any Principal Agreement relating
                  to the release in question will have been complied with; and

                                      -14-
<PAGE>   18

                  (iii) all other documentation required by the TIA (provided
         that any certificates and opinions addressed and delivered to the
         Trustee shall also be addressed to the Collateral Agent), if any, prior
         to the release of Collateral by the Collateral Agent and, in the event
         there is to be a contemporaneous substitution of property for the
         Collateral subject to the sale, lease, transfer or other disposition,
         all documentation necessary to effect the substitution of such new
         Collateral.

         (c) Upon compliance by Tribo and the Restricted Subsidiaries with the
conditions set forth below in respect of any instrument governing a Working
Capital Revolver, to the extent and only to the extent such instrument involves
the creation of Permitted Liens on accounts receivable, related general
intangibles and related proceeds (as used herein, "accounts," "general
intangibles" and "proceeds" shall have the meanings given in the Uniform
Commercial Code as it exists on the date hereof) of Tribo and the Restricted
Subsidiaries to secure Indebtedness Incurred under the Working Capital Revolver,
the Collateral Agent will release the Released Working Capital Revolver Interest
(as defined below) from the Lien of the Indenture and the Security Documents and
reconvey the Released Working Capital Revolver Interests to Tribo or the
Restricted Subsidiaries or such other Person as Tribo or the Restricted
Subsidiary may direct in writing. Tribo and the Restricted Subsidiaries will
have the right to obtain a release of such accounts receivable, related general
intangibles and related proceeds of Tribo and the Restricted Subsidiaries to
secure Indebtedness Incurred under the Working Capital Revolver (the "Released
Working Capital Revolver Interests") upon compliance with the condition that the
Company deliver to the Collateral Agent the following:

                  (i) a notice from the Company requesting the release of the
         Released Working Capital Revolver Interests and attaching the Release
         requested by the Company to be executed by the Collateral Agent;

                  (ii) an Officers' Certificate stating that:

                           (A) such release complies with the terms and
                  conditions of any Hedge Liquidity Agreement, Approved Hedge
                  Agreements and Section 4.09 and Section 4.12 of the Indenture,
                  to the extent applicable; and

                           (B) there is no "Event of Default," "Triggering
                  Event" or "Termination Event" under any of the Principal
                  Agreements or this Agreement that is in effect or continuing
                  on the date thereof or the date of such Incurrence of
                  Indebtedness under the Working Capital Revolver; and

                           (C) the release of the Collateral by the execution of
                  the Release will not result in an "Event of Default,"
                  "Triggering Event" or "Termination Event" under any of the
                  Principal Agreements; and

                           (D) upon the delivery of such Officers' Certificate,
                  all conditions precedent in the Principal Agreements relating
                  to the release in question will have been complied with; and

                                      -15-
<PAGE>   19

                  (iii) all other documentation required by the TIA (provided
         that any certificates and opinions addressed and delivered to the
         Trustee shall also be addressed to the Collateral Agent), if any, prior
         to the release of Collateral by the Collateral Agent.

         (d) Notwithstanding the provisions of this Section 3.02, so long as no
"Event of Default," or "Termination Event" under any Principal Agreement shall
have occurred and be continuing or would result therefrom, Tribo or any
Restricted Subsidiary may engage in any number of ordinary course activities in
respect of the Collateral, in limited dollar amounts specified by the TIA, upon
satisfaction of certain conditions. For example, among other things, subject to
such dollar limitations and conditions, Tribo or a Restricted Subsidiary would
be permitted to:

                  (i) sell or otherwise dispose of any property subject to the
         Lien of the Security Documents, which may have become worn out or
         obsolete; and

                  (ii) abandon, terminate, cancel, release or make alterations
         in or substitutions of any leases or contracts subject to the Lien of
         the Security Documents; and

                  (iii) surrender or modify any franchise, license or permit
         subject to the Lien of the Security Documents which it may own or under
         which it may be operating; and

                  (iv) alter, repair, replace, change the location or position
         of and add to its structures, machinery, systems, equipment, fixtures
         and appurtenances; and

                  (v) demolish, dismantle, tear down or scrap any Collateral or
         abandon any thereof; and

                  (vi) grant farm-outs, leases or sub-leases in respect of real
         property to the extent any of the preceding does not constitute an
         Asset Disposition.

         (e) The Collateral Agent, in its capacity as Collateral Agent under the
Security Documents, shall not at any time release Collateral from the Lien
created by the Security Documents unless such release is in accordance with the
provisions of this Intercreditor Agreement and the Security Documents.

         (f) The release of any Collateral from the terms of the Security
Documents shall not be deemed to impair the security under the Security
Documents in contravention of the provisions thereof if and to the extent the
Collateral is released pursuant to this Intercreditor Agreement and the Security
Documents. To the extent applicable, the Company shall cause TIA Section 314(d)
relating to the release of property from the Lien of the Security Documents and
relating to the substitution therefor of any property to be subjected to the
Lien of the Security Documents to be complied with. Any certificate or opinion
required by TIA Section 314(d) may be made by an Officer of the Company, except
in cases where TIA Section 314(d) requires that such certificate or opinion be
made by an independent Person, which Person shall be an independent engineer,
appraiser or other expert selected or approved by the Collateral Agent or a
Required Creditor in the exercise of reasonable care. For purposes of this
Section 3.02, a Person is "independent" if such Person (a) is in fact
independent, (b) does not have any direct financial interest or any material
indirect financial interest in any

                                      -16-
<PAGE>   20

Obligor or in any Affiliate of the Parent Guarantor and (c) is not an officer,
employee, promoter, underwriter, trustee, partner or director or person
performing similar functions to any of the foregoing for any Obligor. The
Collateral Agent shall be entitled to receive and rely upon a certificate
provided by any such Person confirming that such Person is independent within
the foregoing definition.

         Section 3.03 Deposit, Use and Release of Collateral Account Assets. All
Net Available Cash aggregating in excess of $1,000,000 in any fiscal year from
any Asset Dispositions involving Collateral shall be deposited into a securities
account maintained by the Collateral Agent at its corporate offices or at any
securities intermediary selected by the Trustee having a combined capital and
surplus of at least $250,000,000 and having a long-term debt rating of at least
"A3" by Moody's Investors Service, Inc. and at least "A-" by Standard & Poor's
Ratings Services styled the "Tri-Union Collateral Account" (such account being
the "Collateral Account") which shall be under the exclusive dominion and
control of the Collateral Agent. All amounts on deposit in the Collateral
Account shall be treated as financial assets and cash funds on deposit in the
Collateral Account may be invested by the Collateral Agent, at the direction of
Tribo or the Company, as applicable, in Temporary Cash Investments; provided,
however, in no event shall Tribo or the Company have the right to withdraw funds
or assets from the Collateral Account except in compliance with this Section
3.03 and all assets credited to the Collateral Account shall be subject to a
perfected, first priority Lien in favor of the Collateral Agent for the benefit
of the Approved Hedge Counterparties or Hedge Liquidity Providers (as
applicable), the Trustee and the Holders.

         Any such funds will be released to Tribo or the Company, as the case
may be, by its delivering to the Collateral Agent an Officers' Certificate
stating that:

                  (i) no "Event of Default" or "Termination Event" under any
         Principal Agreement has occurred and is continuing as of the date of
         the proposed release or would result therefrom; and

                  (ii) (A) if such Collateral Account Assets represent Net
         Available Cash in respect of an Asset Disposition, that such funds will
         be applied in accordance with Section 4.10 of the Indenture, to the
         extent applicable, or (B) if such Collateral Account Assets do not
         represent Net Available Cash in respect of an Asset Disposition, that
         such amounts will be utilized in connection with the business of Tribo
         and the Restricted Subsidiaries in compliance with the terms of the
         Principal Agreements; and

                  (iii) all other terms and conditions in the Principal
         Agreements relating to the release in question have been complied with;
         and

                  (iv) all documentation required by the TIA, if any, prior to
         the release of such Collateral Account Assets by the Collateral Agent
         has been delivered to the Collateral Agent and the Trustee.

         Notwithstanding the preceding in this Section 3.03 and subject to the
terms and conditions in the Principal Agreements, (A) if no Triggering Event has
occurred and is continuing and the Company so elects by giving written notice to
the Collateral Agent, the Collateral Agent shall apply the Collateral Account
Assets credited to the Collateral Account to the payment of amounts due

                                      -17-
<PAGE>   21

under any Approved Hedge Agreement (whether regularly scheduled payments or
termination payments) or Hedge Liquidity Agreements (if applicable) or any Note,
including interest due on any interest payment date, and (B) if the Company so
elects, by giving written notice to the Collateral Agent, the Collateral Agent
shall, subject to Section 2.03, apply the Collateral Account Assets credited to
the Collateral Account to the payment of amounts specified in this Agreement as
being secured by the Collateral, including the principal of, and accrued and
unpaid interest on, any Notes at their Stated Maturity or upon redemption or to
the purchase of Notes upon tender or in the open market or at private sale or
upon any exchange or in any one or more of such ways, in each case in compliance
with the Indenture and at the direction of the Company.

         Section 3.04 Form and Sufficiency of Release. In the event that (a) any
Obligor has sold, exchanged, or otherwise disposed of or proposes to sell,
exchange or otherwise dispose of any portion of the Collateral and (b) such
Obligor requests, pursuant to the Indenture and this Agreement, the Collateral
Agent to furnish a written disclaimer, release or quit-claim of any interest in
such property under the Security Documents, then the Collateral Agent, in its
capacity as such under the Security Documents, shall execute, acknowledge and
deliver to such Obligor (in proper form) such an instrument promptly after
satisfaction of the conditions set forth herein for delivery of any such
release. Notwithstanding the preceding sentence, all purchasers and grantees of
any property or rights purporting to be released herefrom shall be entitled to
rely upon any release executed by the Collateral Agent hereunder as sufficient
for the purpose of constituting a good and valid release of the property therein
described from the Lien of the Security Documents.

         Section 3.05 Purchaser Protected. No purchaser or grantee of any
property or rights purporting to be released herefrom shall be bound to
ascertain the authority of the Collateral Agent to execute the release or to
inquire as to the existence of any conditions herein prescribed for the exercise
of such authority; nor shall any purchaser or grantee or any property or rights
permitted by the Principal Agreements to be sold or otherwise disposed of by any
Obligor be under any obligation to ascertain or inquire into the authority of
such Obligor to make such sale or other disposition.

         Section 3.06 Authorization of Actions To Be Taken by the Collateral
Agent Under the Security Documents. Subject to the provisions of the applicable
Security Document, (a) the Collateral Agent may, in its sole discretion and
without the consent of the Creditors, take all actions it deems necessary or
appropriate in order to (i) enforce any of the terms of the Security Documents
and (ii) collect and receive any and all amounts payable in respect of the
Obligations of the Company, the Parent Guarantor or any Subsidiary Guarantor
hereunder and (b) the Collateral Agent shall have power to institute and to
maintain such suits and proceedings as it may deem expedient to prevent any
impairment of the Collateral by any act that may be unlawful or in violation of
the Security Documents or the Principal Agreements, and such suits and
proceedings as the Collateral Agent may deem expedient to preserve or protect
its interests and the interests of the Creditors in the Collateral (including
the power to institute and maintain suits or proceedings to restrain the
enforcement of or compliance with any legislative or other governmental
enactment, rule or order that may be unconstitutional or otherwise invalid if
the enforcement of, or compliance with, such enactment, rule or order would
impair the security interest thereunder or be prejudicial to the interests of
the Creditors). Notwithstanding the above, the Collateral Agent may choose not
to take any action authorized by this Section 3.06 until it receives written
direction from a Required Creditor.

                                      -18-
<PAGE>   22

         Section 3.07 Authorization of Receipt of Funds by the Collateral Agent
under the Security Documents. The Collateral Agent is authorized to receive any
funds for the benefit of the Creditors distributed under the Security Documents,
and to make further distributions of such funds to the Creditors in accordance
with the provisions of this Agreement.

         Section 3.08 Property of Obligors. The Creditors agree that all the
provisions of this Agreement shall apply to any and all properties and rights of
the Obligors or any other Obligor in which the Collateral Agent (in its capacity
as such) or any Creditor at any time acquires a right of set-off or Lien
pursuant to the Security Documents, the Principal Agreements or a judgment
thereunder, including, without limitation, real property or rights in, on or
over real property, notwithstanding any provision to the contrary in any
mortgage, leasehold mortgage or other document purporting to grant or perfect
any Lien in favor of any Creditor or the Collateral Agent.

         Section 3.09 Legends. Each Creditor shall mark, or cause to be marked,
at all times on each note or other instrument evidencing the Obligations to
which it is a holder a legend, in form and substance satisfactory to the
Collateral Agent, indicating that the rights, remedies and obligations of the
Obligors and the holders of such note or other instrument shall be limited by
and subject to the terms of this Agreement.

         Section 3.10 Creditor Dealings; Good Faith. Nothing contained in this
Agreement shall prevent any Creditor from dealing directly or negotiating with
any other Creditor for any purpose, including, but not limited to, the purpose
of attempting to reach agreement as to any vote or proposed vote relating to the
Collateral Agent's actions hereunder, whether or not any Triggering Event or
other "Default", "Event of Default" or "Termination Event" has occurred under
the Principal Agreements.

                                   ARTICLE IV
                           CALCULATION OF OBLIGATIONS

         Section 4.01 Notice of Amount of Obligations. Upon receipt of any
Proceeds to be distributed pursuant to Section 2.03, the Collateral Agent shall
give the Creditors notice thereof, and each Creditor (or its representative)
shall within five (5) Business Days notify the Collateral Agent of the amount of
Obligations owing to it or its group. Such notification shall state the amount
of its (or their) Obligations and how much is then due and owing. If requested
by the Collateral Agent, each Creditor (or its representative) shall demonstrate
that the amounts set forth in its notice are actually owing to such Creditor to
the satisfaction of the Collateral Agent. Notwithstanding the foregoing, the
Collateral Agent may conclusively rely on information in such notices without
investigation.

                                    ARTICLE V
                              THE COLLATERAL AGENT

         Section 5.01 Appointment of Collateral Agent. Each Creditor hereby
designates Wells Fargo Bank Minnesota, National Association to act as the
Collateral Agent for the Creditors under any of the Security Documents, the
enforcement of any Liens granted thereunder and the collection of Proceeds
following the disposition of any such Collateral. Each Creditor hereby
authorizes the Collateral Agent to take such action on its behalf under the
provisions of this Agreement and the

                                      -19-
<PAGE>   23

Security Documents and to exercise such powers and to perform such duties
hereunder and thereunder as are specifically delegated to it hereunder or under
any Security Document or required of the Collateral Agent by the terms hereof or
thereof and such other powers as are reasonably incidental thereto. The
Collateral Agent may perform any of its duties hereunder by or through its
agents or employees. The Collateral Agent agrees to act as Collateral Agent upon
the express terms and conditions contained in this Article V.

         Section 5.02 Nature of Duties of Collateral Agent. The Collateral Agent
shall have no duties or responsibilities, except those expressly set forth in
this Agreement or any Security Document. The Collateral Agent shall have and may
exercise such powers hereunder and under the Security Documents as are
specifically delegated to the Collateral Agent by the terms hereof, together
with such powers as are reasonably incidental thereto. Neither the Collateral
Agent nor any of its directors, officers, employees or agents shall be liable to
the Creditors for any action taken or omitted by it as such hereunder or under
the Security Documents, unless caused solely by its or their gross negligence or
willful misconduct. The duties of the Collateral Agent shall be mechanical and
administrative in nature; and the Collateral Agent, in its capacity as such,
shall not have by reason of this Agreement a fiduciary relationship in respect
of any Creditor. Nothing in this Agreement, expressed or implied, is intended to
or shall be so construed as to impose upon the Collateral Agent any Obligations
in respect of this Agreement and the other Security Documents except as
expressly set forth herein.

         Section 5.03 Lack of Reliance on the Collateral Agent.

         (a) Independently and without reliance upon the Collateral Agent or any
other Creditor, each Creditor represents to the Collateral Agent and each of the
other Creditors that such Creditor has made (i) its own independent
investigation of the financial condition and affairs of the Obligors based on
such documents and information as it has deemed appropriate in connection with
the taking or not taking of any action in connection herewith, and (ii) its own
appraisal of the credit worthiness of the Obligors. Each Creditor also
acknowledges that it will, independently and without reliance upon the
Collateral Agent or any other Person and based on such documents and information
as it shall deem appropriate at the time, continue to make its own credit
decisions in taking or not taking action under this Agreement, the Obligations
or the Security Documents. Except as expressly provided in this Agreement and
the other Security Documents, the Collateral Agent shall have no duty or
responsibility, either initially or on a continuing basis, to provide any
Creditor with any credit or other information concerning the affairs, financial
condition or business of the Obligors which may come into the possession of the
Collateral Agent or any of its affiliates whether now in its possession or in
its possession at any time or times hereafter; and the Collateral Agent shall
not be required to keep itself informed as to the performance or observance by
any Obligor of this Agreement, any Security Document or any other document
referred to or provided for herein or to inspect the Properties or books of any
Obligor.

         (b) The Collateral Agent shall not (i) be responsible to any Creditor
for any recitals, statements, information, representations or warranties herein,
in any Security Document, or in any document, certificate or other writing
delivered in connection herewith or therewith or for the execution,
effectiveness, genuineness, validity, enforceability, collectability, priority
or sufficiency of this Agreement, the Obligations or the Security Documents or
the financial condition of the Obligors; or (ii) be required to make any inquiry
concerning the performance or observance by others of any

                                      -20-
<PAGE>   24

of the terms, provisions or conditions of this Agreement, including the content
of notices, opinions, certificates and directions given under this Agreement
(However, the Collateral Agent shall examine such certificates, notices,
opinions and directions to determine whether or not they conform to this
Agreement and the Security Documents.), the Obligations or the Security
Documents, the financial condition of the Obligors, or the existence or possible
existence of any "Default" or "Event of Default" under the Principal Agreements;
provided, that the Collateral Agent will promptly notify each Creditor of any
Default, Event of Default or Termination Event of which a responsible officer of
the Collateral Agent has actual knowledge.

         Section 5.04 Certain Rights of the Collateral Agent. If the Collateral
Agent shall request instructions from the Creditors with respect to any act or
action (including the failure to act) in connection with this Agreement, the
Obligations or the Security Documents, the Collateral Agent shall be entitled to
refrain from such act or taking such action unless and until the Collateral
Agent shall have received written instructions from any Creditor or group of
Creditors pursuant to the terms hereof; and the Collateral Agent shall not incur
liability to any Person by reason of so refraining. Without limiting the
foregoing, no Creditor shall have any right of action whatsoever against the
Collateral Agent as a result of the Collateral Agent acting or refraining from
acting under this Agreement or the Security Documents in accordance with the
written instructions given in accordance with this Agreement and such
instructions and any action taken or failure to act pursuant thereto shall be
binding on all the Creditors. Except for action expressly required of the
Collateral Agent pursuant to the terms hereof, the Collateral Agent shall be
fully justified in failing or refusing to take any action hereunder or under the
Security Documents unless it shall first be indemnified to its satisfaction by
the Obligors or the Creditors against any and all liability and expense which
may be incurred by the Collateral Agent by reason of taking or continuing to
take any such action. Notwithstanding any other provision of this Article V or
any indemnity or instructions provided by any or all of the Creditors, the
Collateral Agent shall not be required to take any action which exposes the
Collateral Agent to personal liability or which is contrary to this Agreement,
the Security Documents or applicable law.

         Section 5.05 Reliance by Collateral Agent. The Collateral Agent shall
be entitled to rely, and shall be fully protected in relying, upon any writing,
resolution, notice, statement, certificate or telecopier message, cablegram,
radiogram, order or other documentary, teletransmission or telephone message
believed by it to be genuine and correct and to have been signed, sent or made
by the proper Person. The Collateral Agent may consult with independent legal
counsel (which shall not be counsel for the Obligors), independent public
accountants and other experts selected by it and shall not be liable for any
action taken or omitted to be taken by it in good faith in accordance with the
advice of such counsel, accountants or experts.

         Section 5.06 Collateral Agent's Reimbursements and Indemnification. TO
THE EXTENT THE COLLATERAL AGENT IS NOT REIMBURSED BY THE COMPANY OR ANY OTHER
OBLIGOR, EACH PARTY HERETO WILL REIMBURSE AND INDEMNIFY THE COLLATERAL AGENT, IN
PROPORTION TO ITS PRO RATA SHARE, FOR AND AGAINST ANY AND ALL ACTIONS, SUITS,
PROCEEDINGS (INCLUDING ANY INVESTIGATIONS, LITIGATION OR INQUIRIES), CLAIMS,
DEMANDS, CAUSES OF ACTION, COSTS, LOSSES, LIABILITIES, DAMAGES OR EXPENSES OF
ANY KIND OR NATURE WHATSOEVER WHICH MAY BE IMPOSED ON, INCURRED BY OR ASSERTED
AGAINST THE COLLATERAL AGENT IN PERFORMING ITS DUTIES HEREUNDER OR UNDER ANY
SECURITY DOCUMENT OR OTHERWISE IN CONNECTION HEREWITH OR THEREWITH, INCLUDING
LOSSES OCCURRING FROM THE ORDINARY AND/OR

                                      -21-
<PAGE>   25

COMPARATIVE NEGLIGENCE OF THE COLLATERAL AGENT, IN ANY WAY RELATING TO OR
ARISING OUT OF THIS AGREEMENT; PROVIDED THAT NO CREDITOR SHALL BE LIABLE FOR ANY
PORTION OF SUCH LIABILITIES, OBLIGATIONS, LOSSES, DAMAGES, PENALTIES, ACTIONS,
JUDGMENTS, SUITS, COSTS, EXPENSES OR DISBURSEMENTS TO THE EXTENT RESULTING FROM
THE COLLATERAL AGENT'S GROSS NEGLIGENCE OR WILLFUL MISCONDUCT.

         Section 5.07 The Collateral Agent in its Individual Capacity. The
Collateral Agent shall have the same rights and powers hereunder as any other
Creditor and may exercise the same as though it were not performing the duties
specified herein; and the term "Creditors" or any similar term shall, unless the
context clearly otherwise indicates, include the Collateral Agent, in its
individual capacity as and to the extent it is a Holder of any Note and not in
its capacity as the Collateral Agent. The Collateral Agent may accept deposits
from, lend money to, and generally engage in any kind of banking, trust,
financial advisory or other business with the Obligors as if it were not
performing the duties specified herein, and may accept fees and other
consideration from the Obligors for services in connection with this Agreement
and otherwise without having to account for the same to the Creditors except as
specified herein.

         Section 5.08 Creditors as Owners. The Collateral Agent may deem and
treat each Creditor as the owner of such Creditor's Obligations for all purposes
hereof unless and until the Collateral Agent is notified of a change in
Creditors.

         Section 5.09 Successor Collateral Agent.

         (a) The Collateral Agent (i) may resign at any time by giving sixty
(60) days prior written notice thereof to the Creditors and the Company, (ii)
shall promptly resign if any conflict of interest arises involving any group of
Creditors and another group of Creditors for whom it is a trustee or fiduciary
under one of the Principal Agreements and (iii) may be removed at any time by
the Required Creditors, which resignation or removal, in each case, shall be
effective upon the appointment of a successor to the Collateral Agent. Upon any
such resignation or removal, the Required Creditors shall have the right to
appoint a successor Collateral Agent. If within thirty (30) days after the
retiring Collateral Agent's giving of notice of resignation or the Required
Creditors' removal of the retiring Collateral Agent, no successor Collateral
Agent shall have been so appointed by the Required Creditors and accepted such
appointment, then, the retiring Collateral Agent may, on behalf of the
Creditors, appoint a successor Collateral Agent, which shall be a bank which
maintains an office in the United States of America, or a commercial bank
organized under the laws of the United States of America or of any State
thereof, or any affiliate of such bank, having a combined capital and surplus of
at least $50,000,000 as of the date of its most recent financial statements.

         (b) Upon the acceptance of any appointment as Collateral Agent
hereunder by a successor Collateral Agent, such successor Collateral Agent shall
thereupon succeed to and become vested with all the rights, powers, privileges
and duties of the retiring Collateral Agent, and the retiring Collateral Agent
shall be discharged from its duties under this Agreement. After any retiring
Collateral Agent's resignation or removal hereunder as Collateral Agent, the
provisions of this Agreement shall inure to its benefit as to any actions taken
or omitted to be taken by it while it was Collateral Agent under this Agreement.

                                      -22-
<PAGE>   26

         Section 5.10 Employment of Collateral Agent and Counsel. The Collateral
Agent may execute any of its duties as Collateral Agent hereunder or under the
Security Documents by or through employees, agents, and attorneys-in-fact and
shall not be answerable to the Creditors for the default or misconduct of any
such agents or attorneys-in-fact selected by it with reasonable care, provided
that the Collateral Agent shall always be obligated to account for moneys or
securities received by it or its authorized agents. The Collateral Agent shall
be entitled to advice of independent counsel concerning all matters pertaining
to the agency hereby created and its duties hereunder or under the Security
Documents.

         Section 5.11 Limitation on Liability of the Creditors and Collateral
Agent. The Creditors and Collateral Agent shall not be deemed, as a result of
the execution and delivery of the Security Documents or the consummation of the
transactions contemplated by this Agreement and the Security Documents, to have
assumed any obligation of any Obligor with respect to the Collateral or any
liability under or with respect to any of the contracts, agreements, leases,
instruments or documents which are, or which may hereafter be, assigned to the
Collateral Agent for the benefit of the Creditors.

                                   ARTICLE VI
                                  MISCELLANEOUS

         Section 6.01 Authority. The parties hereto represent and warrant that
they have all requisite power to, and have been duly authorized to, enter into
this Agreement.

         Section 6.02 Termination/Withdrawal/Redesignation of Contracts.

         (a) Subject to Section 2.09 and Section 6.02(b), this Agreement shall
terminate upon receipt by the Collateral Agent of evidence satisfactory to it
that (i) all Obligations have been paid in full and all obligations in respect
of the Principal Agreements have been satisfied in full, and (ii) the
termination of the Principal Agreements and the Security Documents pursuant to
the terms thereof.

         (b) (i) If all of the Approved Hedge Agreements with an Approved Hedge
Counterparty have been paid in full, terminated (and all settlement amounts,
unpaid amounts, interest and other amounts then due to such Approved Hedge
Counterparty have been paid in full) or the terms of all such contracts have
otherwise expired, then the Company may, by written notice to the Collateral
Agent, the Trustee and such counterparty, remove such counterparty as an
"Approved Hedge Counterparty" under this Agreement and the Security Documents;
and upon delivery of such notice, such counterparty shall cease to be an
"Approved Hedge Counterparty" for all such purposes.

                  (ii) Any "Approved Hedge Counterparty" under this Agreement
         and the Security Documents may at any time elect to no longer be an
         "Approved Hedge Counterparty" under this Agreement by giving notice to
         the Collateral Agent, the Trustee and the Company; and upon delivery of
         such notice, such counterparty shall cease to be an "Approved Hedge
         Counterparty" for all such purposes, and each Oil and Gas Hedging
         Contract shall cease to be an Approved Hedge Agreement.

                  (iii) If the Company has entered into a Hedge Liquidity
         Agreement and has issued to an Approved Hedge Counterparty a letter of
         credit (such letter of credit to be in form and substance and in an
         amount and from an issuing bank satisfactory to the Approved Hedge

                                      -23-
<PAGE>   27

         Counterparty in its sole discretion) to secure payment of its
         obligations under the Approved Hedge Agreements to which such Approved
         Hedge Counterparty is a party, such Person shall cease to be an
         Approved Hedge Counterparty for purposes of this Agreement and the
         Security Documents and each such contract shall cease to be an Approved
         Hedge Agreement for all purposes of this Agreement and the Security
         Documents. Issuance of a letter of credit pursuant to this paragraph
         (iii) must be accompanied by (A) notice to the Collateral Agent and the
         Trustee and (B) the execution and delivery to the Trustee and
         Collateral Agent of a supplement in the form of Annex 3 hereto making
         the issuing bank party to the above referenced Hedge Liquidity
         Agreement a party to this Agreement as a Hedge Liquidity Provider for
         all purposes.

         Section 6.03 Amendments. Amendments, modifications, supplements,
waivers, consents and approvals of or in connection with:

         (a) this Agreement and any Security Document may be effectuated only
upon the written consent of each of the Approved Hedge Counterparties then a
party hereto, Hedge Liquidity Providers having greater than 50% of the aggregate
commitments of the Hedge Liquidity Providers if a Hedge Liquidity Agreement is
in place and Holders having 50% or more of the outstanding principal amount of
the then outstanding principal amount of the Notes (and, if the rights or duties
of the Collateral Agent or the Trustee or any Obligors are affected thereby, by
the Collateral Agent, the Trustee or the applicable Obligor, as the case may
be); provided, however, that (i) Section 2.03 (and the defined terms used
therein) shall not be amended without the unanimous written consent of each
Creditor (and, if the rights or duties of the Collateral Agent or the Trustee or
any Obligors are affected thereby, by the Collateral Agent, the Trustee or the
applicable Obligor, as the case may be), (ii) amendments to Security Documents
requested in connection with releases of Collateral which comply with the terms
of Section 3.02 which only amend the Security Documents to the extent necessary
to grant the release may be made without the consent of the Creditors, (iii) any
waiver of Triggering Events, Releases of Collateral (except Asset Dispositions,
Released Working Capital Revolver Interests and Releases of Collateral Account
Assets in accordance with the terms of this Agreement) and any release of an
Obligor requires approval of the Approved Hedge Counterparties and (iii) no
Security Document may be amended if the effect thereof would be (A) to secure
additional Obligations (other than additional Notes issued under clause 2.02 of
the Indenture) or any other obligations, (B) to secure indebtedness or
obligations owed in favor of any other creditor or groups of creditors, (C) to
change the priority of or subordinate the Liens created thereby, (D) to modify
any material remedy provided for therein, or (E) to cause the Indenture
Obligations, any Hedge Liquidity Obligations and the Approved Hedge Counterparty
Obligations to not be equally and ratably secured thereby (subject to the
priorities set forth herein); and

         (b) the Principal Agreements may be effectuated only in accordance with
the terms contained therein.

         Section 6.04 Notices, etc. All notices and other communications
hereunder shall be given in writing and shall be given to such Person at its
address or telecopy number as follows:

         To the Company or any Obligor:

         Tri-Union Development Corporation
         530 Lovett Boulevard

                                      -24-
<PAGE>   28

         Houston, Texas 77006-4021
         Attention: Chief Financial Officer
         Phone: (713) 533-4000

         To the Collateral Agent:

         Wells Fargo Bank Minnesota, National Association
         Corporate Trust Services
         Sixth and Marquette Avenue
         MAC N9303-120
         Minneapolis, MN 55479
         Attention: Tri-Union Administrator
         Telecopier: (612) 667-9825

         To the Trustee:

         Firstar Bank, National Association
         101 East Fifth Street, 12th Floor
         St. Paul, MN 55101
         Attention: Frank Leslie
         Telecopier: (651) 229-6415
         Phone: (651) 229-2600

or such other address or telecopy number a Person may hereafter specify by
notice to the Collateral Agent (who shall promptly notify the Obligors and the
other Creditors); provided, however, that any notices or other communications
required to be given to the Holders hereunder shall be deemed to be given to the
Holders if given to the Trustee in accordance with the terms of this Section
6.04. Each notice or other communication shall be effective (a) if given by
mail, upon receipt, (b) if given by telecopier during regular business hours,
once such telecopy is transmitted to the telecopy number provided in writing to
the Collateral Agent by each Creditor and by each Obligor, respectively, or (c)
if given by any other means, upon receipt; provided that notices to the
Collateral Agent are not effective until received.

         SECTION 6.05 PAYMENT OF EXPENSES AND TAXES; INDEMNIFICATION. EACH
OBLIGOR JOINTLY AND SEVERALLY AGREES (A) TO PAY OR REIMBURSE THE COLLATERAL
AGENT AND EACH CREDITOR (OTHER THAN HOLDERS) FOR ALL OF THEIR RESPECTIVE
OUT-OF-POCKET COSTS AND EXPENSES INCURRED IN CONNECTION WITH THE DEVELOPMENT,
PREPARATION AND EXECUTION OF, AND ANY AMENDMENT, SUPPLEMENT OR MODIFICATION TO,
THIS AGREEMENT AND THE OTHER TRANSACTION DOCUMENTS AND ANY OTHER DOCUMENTS
PREPARED IN CONNECTION HEREWITH OR THEREWITH, AND THE CONSUMMATION AND
ADMINISTRATION OF THE TRANSACTIONS CONTEMPLATED HEREBY AND THEREBY, INCLUDING
THE REASONABLE FEES AND DISBURSEMENTS OF COUNSEL TO THE COLLATERAL AGENT AND
EACH CREDITOR (OTHER THAN HOLDERS) AND FILING AND RECORDING FEES AND EXPENSES,
WITH STATEMENTS WITH RESPECT TO THE FOREGOING TO BE SUBMITTED TO THE COMPANY
PRIOR TO THE CLOSING DATE (IN THE CASE OF AMOUNTS TO BE PAID ON THE CLOSING
DATE) AND FROM TIME TO TIME THEREAFTER ON A QUARTERLY BASIS OR SUCH OTHER
PERIODIC BASIS AS THE COLLATERAL AGENT SHALL DEEM APPROPRIATE, (B) TO PAY OR
REIMBURSE EACH CREDITOR (OTHER THAN HOLDERS) AND THE COLLATERAL AGENT FOR ALL OF
THEIR RESPECTIVE COSTS AND EXPENSES INCURRED IN

                                      -25-
<PAGE>   29

CONNECTION WITH THE ENFORCEMENT OR PRESERVATION OF ANY RIGHTS UNDER THIS
AGREEMENT, THE OTHER TRANSACTION DOCUMENTS AND ANY SUCH OTHER DOCUMENTS,
INCLUDING THE FEES AND DISBURSEMENTS OF COUNSEL (AND OTHER AGENTS AND
PROFESSIONALS), TO EACH CREDITOR (OTHER THAN HOLDERS) AND TO THE COLLATERAL
AGENT, (C) TO PAY, INDEMNIFY, AND HOLD EACH CREDITOR AND THE COLLATERAL AGENT
HARMLESS FROM AND AGAINST, ANY AND ALL RECORDING AND FILING FEES AND ANY AND ALL
LIABILITIES WITH RESPECT TO, OR RESULTING FROM ANY DELAY IN PAYING, STAMP,
EXCISE AND OTHER TAXES, IF ANY, THAT MAY BE PAYABLE OR DETERMINED TO BE PAYABLE
IN CONNECTION WITH THE EXECUTION AND DELIVERY OF, OR CONSUMMATION OR
ADMINISTRATION OF ANY OF THE TRANSACTIONS CONTEMPLATED BY, OR ANY AMENDMENT,
SUPPLEMENT OR MODIFICATION OF, OR ANY WAIVER OR CONSENT UNDER OR IN RESPECT OF,
THIS AGREEMENT, THE OTHER TRANSACTION DOCUMENTS AND ANY SUCH OTHER DOCUMENTS,
AND (D) TO PAY, INDEMNIFY, AND HOLD EACH CREDITOR AND THE COLLATERAL AGENT AND
THEIR RESPECTIVE OFFICERS, DIRECTORS, EMPLOYEES, AFFILIATES, AGENTS AND
CONTROLLING PERSONS (EACH, AN "INDEMNITEE") HARMLESS FROM AND AGAINST ANY AND
ALL OTHER LIABILITIES, OBLIGATIONS, LOSSES, DAMAGES, PENALTIES, ACTIONS,
JUDGMENTS, SUITS, COSTS, EXPENSES OR DISBURSEMENTS OF ANY KIND OR NATURE
WHATSOEVER WITH RESPECT TO THE EXECUTION, DELIVERY, ENFORCEMENT, PERFORMANCE AND
ADMINISTRATION OF THIS AGREEMENT, THE OTHER TRANSACTION DOCUMENTS AND ANY SUCH
OTHER DOCUMENTS, INCLUDING ANY OF THE FOREGOING RELATING TO THE USE OF PROCEEDS
OF THE NOTES OR THE VIOLATION OF, NONCOMPLIANCE WITH OR LIABILITY UNDER, ANY
ENVIRONMENTAL LAW APPLICABLE TO THE OPERATIONS OF ANY OBLIGOR, ANY OF ITS
SUBSIDIARIES OR ANY OF THE COLLATERAL AND THE REASONABLE FEES AND EXPENSES OF
LEGAL COUNSEL IN CONNECTION WITH CLAIMS, ACTIONS OR PROCEEDINGS BY ANY
INDEMNITEE AGAINST ANY OBLIGOR UNDER ANY TRANSACTION DOCUMENT (ALL THE FOREGOING
IN THIS CLAUSE (D), COLLECTIVELY THE "INDEMNIFIED LIABILITIES"), PROVIDED, THAT
NO OBLIGOR SHALL HAVE ANY OBLIGATION HEREUNDER TO ANY INDEMNITEE WITH RESPECT TO
INDEMNIFIED LIABILITIES TO THE EXTENT SUCH INDEMNIFIED LIABILITIES ARE FOUND BY
A FINAL AND NONAPPEALABLE DECISION OF A COURT OF COMPETENT JURISDICTION TO HAVE
RESULTED FROM THE GROSS NEGLIGENCE OR WILLFUL MISCONDUCT OF SUCH INDEMNITEE.
WITHOUT LIMITING THE FOREGOING, AND TO THE EXTENT PERMITTED BY APPLICABLE LAW,
EACH OBLIGOR AGREES NOT TO ASSERT AND TO CAUSE ITS SUBSIDIARIES NOT TO ASSERT,
AND HEREBY WAIVES AND AGREES TO CAUSE ITS SUBSIDIARIES TO SO WAIVE, ALL RIGHTS
FOR CONTRIBUTION OR ANY OTHER RIGHTS OF RECOVERY WITH RESPECT TO ALL CLAIMS,
DEMANDS, PENALTIES, FINES, LIABILITIES, SETTLEMENTS, DAMAGES, COSTS AND EXPENSES
OF WHATEVER KIND OR NATURE, UNDER OR RELATED TO ENVIRONMENTAL LAWS, THAT ANY OF
THEM MIGHT HAVE BY STATUTE OR OTHERWISE AGAINST ANY INDEMNITEE. WITHOUT LIMITING
ANY PROVISION OF THIS AGREEMENT OR OF ANY OTHER TRANSACTION DOCUMENT, IT IS THE
EXPRESS INTENTION OF THE PARTIES HERETO THAT EACH INDEMNITEE SHALL BE
INDEMNIFIED FROM AND HELD HARMLESS AGAINST ANY AND ALL INDEMNIFIED LIABILITIES
ARISING OUT OF OR RESULTING FROM THE SOLE OR CONTRIBUTORY NEGLIGENCE OF SUCH
INDEMNITEE. ALL AMOUNTS DUE UNDER THIS SECTION 6.05 SHALL BE PAYABLE PROMPTLY
AND IN ANY EVENT, NOT LATER THAN 10 DAYS AFTER WRITTEN DEMAND THEREFOR.
STATEMENTS PAYABLE BY THE OBLIGORS PURSUANT TO THIS SECTION 6.05 SHALL BE
SUBMITTED TO KELLY PLATO (TELEPHONE NO. 713-533-4000), AT THE ADDRESS OF THE
COMPANY SET FORTH IN SECTION 6.04, OR TO SUCH OTHER PERSON OR ADDRESS AS MAY BE
HEREAFTER DESIGNATED BY THE OBLIGORS IN A WRITTEN NOTICE TO THE COLLATERAL
AGENT. THE AGREEMENTS IN THIS SECTION 6.05 SHALL SURVIVE REPAYMENT OF THE NOTES,
THE APPROVED HEDGE AGREEMENTS AND ALL AMOUNTS PAYABLE HEREUNDER.

                                      -26-
<PAGE>   30

         Section 6.06 Applicable Law. THIS AGREEMENT (INCLUDING, BUT NOT LIMITED
TO, THE VALIDITY AND ENFORCEABILITY HEREOF AND THEREOF) SHALL BE GOVERNED BY,
AND CONSTRUED IN ACCORDANCE WITH, THE LAWS OF THE STATE OF NEW YORK (WITHOUT
REGARD TO ANY PRINCIPLES OF LAW THAT WOULD REQUIRE THE APPLICATION OF THE LAWS
OF ANOTHER STATE).

         Section 6.07 Entire Agreement. This Agreement, the Principal Agreements
and the Security Documents embody the entire agreement and understanding between
the Collateral Agent, Creditors and the Obligors and supersede all prior
agreements and understandings between such parties relating to the subject
matter hereof and thereof. There are no unwritten oral agreements between the
parties.

         Section 6.08 Execution in Counterparts. This Agreement may be executed
in any number of counterparts, each of which when so executed shall be deemed to
be an original and all of which taken together shall constitute one and the same
agreement. Any signature page of a counterpart may be detached therefrom without
impairing the legal effect of the signatures thereon and attached to another
counterpart identical in form thereto but having attached to it one or more
additional signature pages signed by other parties.

         Section 6.09 Severability. If any term or provision of this Agreement
shall be determined to be illegal or unenforceable, all other terms and
provisions of this Agreement shall nevertheless remain effective and shall be
enforced to the fullest extent permitted by applicable law.

         Section 6.10 Conflict with Security Documents. If there is a conflict
between the terms and provisions contained in the Security Documents and the
terms and provisions contained herein, the terms and provisions contained in
this Agreement shall control.

         Section 6.11 Limitation by Law. All rights, remedies and powers
provided herein may be exercised only to the extent that the exercise thereof
does not violate any applicable provision of law; and all the provisions hereof
are intended (a) to be subject to all applicable mandatory provisions of law
which may be controlling and (b) to be limited to the extent necessary so that
they will not render this Agreement, any Principal Agreement or any Security
Document invalid under the provisions of any applicable law.

         Section 6.12 Benefit of Agreement; Limitation on Assignment. The terms
and provisions of this Agreement shall be binding upon and inure to the benefit
of each Creditor and its respective successors and assigns. Except as set forth
in Section 6.02(b), the terms and provisions of this Agreement shall not inure
to the benefit of, nor be relied upon by, the Obligors or their successors or
assigns. No Approved Hedge Counterparty or Hedge Liquidity Provider shall
assign, transfer or sell any part of its portion of the Obligations, unless in
connection with such assignment, transfer or sale, such assignee, transferee or
purchaser shall first become a party to this Agreement.

         Section 6.13 Further Assurances, Recording and Opinions.

         (a) The parties hereto agree to take all such further actions and to
execute, acknowledge and deliver all such further documents that are necessary
or useful to carry out the purposes of this Agreement.

                                      -27-
<PAGE>   31

         (b) The Company shall furnish to the Trustee and the Collateral Agent,
at such time as required by Section 314(b) of the TIA, Opinion(s) of Counsel
either (i) substantially to the effect that, in the opinion of such counsel, the
grant of a Lien in the Collateral intended to be made by the Security Documents
and all other instruments of further assurance, including, without limitation,
financing statements, have been properly recorded and filed to the extent
necessary to perfect the Lien in the Collateral created by the Security
Documents and reciting the details of such action, and stating that as to the
Liens created pursuant to the Security Documents, such recordings and filings
are the only recordings and filings necessary to give notice thereof and that no
re-recordings or refilings are necessary to maintain such notice (other than as
stated in such opinion), or (ii) to the effect that, in the opinion of such
counsel, no such action is necessary to perfect such Lien.

         (c) To the extent required by the TIA, the Company shall furnish to the
Trustee and the Collateral Agent on July 1 in each year, beginning with 2002, an
Opinion of Counsel, dated as of such date, either (i)(A) stating that, in the
opinion of such counsel, action has been taken with respect to the recording,
filing, re-recording and refiling of all supplemental mortgages, financing
statements, continuation statements and other documents as is necessary to
maintain the Lien of the Security Documents and reciting with respect to the
Lien in the Collateral the details of such action or referring to prior Opinions
of Counsel in which such details are given, and (B) stating that, based on
relevant laws as in effect on the date of such Opinion of Counsel, all financing
statements, continuation statements and other documents have been executed and
filed that are necessary as of such date and during the succeeding 24 months
fully to maintain the Lien of the Collateral Agent under the Security Documents
with respect to the Collateral, or (ii) stating that, in the opinion of such
counsel, no such action is necessary to maintain such Lien.

         Section 6.14 No Impairment. The terms of this Agreement and the rights
of each Creditor in the Collateral and the obligations of the other Creditors
arising hereunder shall not be affected, modified or impaired in any manner or
to any extent by (i) any amendment or modification of or supplement to any of
the Principal Agreements, Security Documents, or any agreement, instrument or
document executed or delivered pursuant thereto, (ii) any lack of validity or
enforceability of any of the Principal Agreements, Security Documents, or other
agreements, instrument or documents referred to in clause (i) above, (iii) the
exercise of or failure to exercise any right, power or remedy under or in
respect of the Obligations or any of the Principal Agreements, Security
Documents, or other agreements, instruments or documents referred to in clause
(i) above arising at law, or (iv) any waiver, consent, release, indulgence,
extension, renewal, modification, delay or other action, inaction or omission
(other than in accordance with the provisions of this Agreement) in respect of
the Obligations or any of the Principal Agreements, Security Documents, or other
agreements, instruments or documents referred to in clause (i) above or in
respect of any of the properties or assets now or hereafter constituting
Collateral, whether or not the other Creditors shall have had notice or
knowledge of any of the foregoing and whether or not they shall have consented
thereto.

         Section 6.15 Status of Obligations. Each Obligor, the Collateral Agent
and each of the Creditors represents and warrants to each of the other parties
hereto that this Agreement has been duly authorized, executed and delivered by
such representing and warranting party and is the legal, valid, binding and
enforceable obligation of such party, subject to bankruptcy, insolvency,
reorganization, moratorium and other laws of general application affecting the
rights and remedies of creditors and subject to general equitable principles,
including without limitation the principle that

                                      -28-
<PAGE>   32

equitable remedies, such as the remedy of specific performance, are subject to
the discretion of the court.

         Section 6.16 Counterclaims and Defenses by Obligors. Each Obligor
agrees that it will not assert against the Collateral Agent (in its capacity as
such) or the Creditors as a group any claim, defense, counterclaim, recoupment
or right of set-off which it may have solely against one or more (but not all)
of the Creditors (other than against the Collateral Agent in its capacity as
such), nor will such Obligor assert against any one of the Creditors any claim,
defense, counterclaim, recoupment or right of set-off which it may have solely
against another of the Creditors. Nothing in this Section 6.16 shall limit any
other waiver of claims, defenses, counterclaims, recoupments or rights of
set-off any Obligor may have made in any Transaction Document.

      [REMAINDER OF PAGE INTENTIONALLY LEFT BLANK. SIGNATURE PAGES FOLLOW.]

                                      -29-
<PAGE>   33

         IN WITNESS WHEREOF, the parties have caused their duly authorized
representatives to execute this Agreement as of the date first above written.

CREDITORS:

                                    WELLS FARGO BANK MINNESOTA, NATIONAL
                                    ASSOCIATION, as Collateral Agent

                                    By:
                                        ----------------------------------------
                                    Name:  Jane Y. Schweiger
                                    Title: Assistant Vice President

                  [Intercreditor Agreement - Signature Page 1]
<PAGE>   34

                                    FIRSTAR BANK, NATIONAL ASSOCIATION,
                                    as Trustee

                                    By:
                                        ----------------------------------------
                                    Name:  Frank P. Leslie, III
                                    Title: Vice President

                  [Intercreditor Agreement - Signature Page 2]
<PAGE>   35

Each Obligor hereby executes this Agreement to evidence its agreement that:

         1.       It shall be bound by all of the terms and provisions of this
                  Agreement.

         2.       It acknowledges and agrees that the terms of this Agreement
                  shall control over the terms of the Security Documents to the
                  extent of any conflict relating to the relative rights of the
                  Creditors.

         3.       THE INDEMNITY AND REIMBURSEMENT PROVISIONS CONTAINED IN
                  SECTION 6.05 SHALL APPLY TO ALL MATTERS UNDER THIS AGREEMENT
                  AND EACH OBLIGOR JOINTLY AND SEVERALLY AGREES TO INDEMNIFY AND
                  REIMBURSE THE INDEMNITEES IN ACCORDANCE WITH THE TERMS
                  THEREOF.

         4.       Except as stated in Section 6.03 hereof, the terms and
                  provisions of this Agreement shall inure solely to the benefit
                  of the each Creditor and its respective successors and assigns
                  and the terms and provisions of this Agreement shall not inure
                  to the benefit of nor be enforceable by any Obligor. This
                  Agreement may be amended as provided herein without the
                  necessity of any Obligor joining in any such amendment,
                  provided, that no Obligor shall be bound by any amendment
                  which would have the effect of increasing its Obligations and
                  indemnities hereunder or materially affecting its rights or
                  duties under the Security Documents unless it shall have
                  consented to such amendment.

         5.       The Company hereby covenants and agrees to cause each new
                  Obligor to execute a supplemental Intercreditor and Collateral
                  Agency Agreement in the form of Annex 2 hereto.

         6.       It at its expense will execute, acknowledge and deliver all
                  such agreements and instruments and take all such action as
                  the Collateral Agent or any Creditor from time to time may
                  reasonably request in order to further effectuate the purposes
                  of this Agreement and to carry out the terms hereof.

                                    TRI-UNION DEVELOPMENT CORPORATION

                                    By:
                                        ----------------------------------------
                                    Name:  Richard Bowman
                                    Title: President and Chief Executive Officer

                                    TRIBO PETROLEUM CORPORATION

                                    By:
                                        ----------------------------------------
                                    Name:  Richard Bowman
                                    Title: President and Chief Executive Officer

                  [Intercreditor Agreement - Signature Page 3]
<PAGE>   36

                                    TRI-UNION OPERATING COMPANY

                                    By:
                                        ----------------------------------------
                                    Name:  Richard Bowman
                                    Title: President and Chief Executive Officer

                  [Intercreditor Agreement - Signature Page 4]
<PAGE>   37

                                    BANK OF AMERICA, N.A.,
                                    as Approved Hedge Counterparty

                                    By:
                                       -----------------------------------------
                                    Name:
                                         ---------------------------------------
                                    Title:
                                          --------------------------------------

                  [Intercreditor Agreement - Signature Page 5]<PAGE>   1
                                                                     EXHIBIT 4.6

                          PLEDGE AND COLLATERAL ACCOUNT
                                    AGREEMENT

                                      AMONG

                WELLS FARGO BANK MINNESOTA, NATIONAL ASSOCIATION,
                              AS COLLATERAL AGENT,
                            (AS ENTITLEMENT HOLDER),

                WELLS FARGO BANK MINNESOTA, NATIONAL ASSOCIATION,
                          (AS SECURITIES INTERMEDIARY)

                                       AND

                          TRIBO PETROLEUM CORPORATION,
                        TRI-UNION DEVELOPMENT CORPORATION
                        AND TRI-UNION OPERATING COMPANY,
                                   AS OBLIGORS

                                  JUNE 18, 2001

<PAGE>   2
<Table>
<Caption>
                                TABLE OF CONTENTS

                                                                                    Page
                                                                                    ----
<S>                     <C>                                                        <C>
ARTICLE I DEFINITIONS..................................................................1

   SECTION 1.01         TERMS DEFINED ABOVE; INDENTURE AND INTERCREDITOR TERMS.........1
   SECTION 1.02         CERTAIN DEFINITIONS............................................2
   SECTION 1.03         RULES OF CONSTRUCTION..........................................2

ARTICLE II SECURITY INTEREST...........................................................3

   SECTION 2.01         PLEDGE.........................................................3
   SECTION 2.02         TRANSFER OF COLLATERAL.........................................3

ARTICLE III THE COLLATERAL ACCOUNT.....................................................3

   SECTION 3.01         ESTABLISHMENT AND CHARACTER OF COLLATERAL ACCOUNT..............3
   SECTION 3.02         THE SECURITIES INTERMEDIARY; ETC...............................4
   SECTION 3.03         INVESTMENT DIRECTION AND CONTROL...............................4
   SECTION 3.04         SUBORDINATION OF SECURITIES INTERMEDIARY LIEN..................5
   SECTION 3.05         NO OTHER AGREEMENTS............................................5
   SECTION 3.06         TREASURY BILLS.................................................6

ARTICLE IV REPRESENTATIONS AND WARRANTIES..............................................6

   SECTION 4.01         OWNERSHIP OF COLLATERAL; ENCUMBRANCES..........................6
   SECTION 4.02         NO REQUIRED CONSENT............................................6
   SECTION 4.03         FIRST PRIORITY SECURITY INTEREST...............................6
   SECTION 4.04         COLLATERAL.....................................................6
   SECTION 4.05         CHIEF EXECUTIVE OFFICE; PRINCIPAL PLACE OF BUSINESS;
                        JURISDICTION OF FORMATION......................................6
   SECTION 4.06         DUE AUTHORIZATION, ETC.........................................7

ARTICLE V COVENANTS AND AGREEMENTS.....................................................7

   SECTION 5.01         SALE, DISPOSITION OR ENCUMBRANCE OF COLLATERAL.................7
   SECTION 5.02         FURTHER ASSURANCES.............................................7
   SECTION 5.03         FINANCING STATEMENT............................................7
   SECTION 5.04         RECORDS AND INFORMATION........................................7

ARTICLE VI RIGHTS, DUTIES, AND POWERS OF THE COLLATERAL AGENT..........................8

   SECTION 6.01         DISCHARGE ENCUMBRANCES.........................................8
   SECTION 6.02         CUMULATIVE AND OTHER RIGHTS....................................8
   SECTION 6.03         DISCLAIMER OF CERTAIN DUTIES...................................8
   SECTION 6.04         CUSTODY AND PRESERVATION OF THE COLLATERAL.....................8

ARTICLE VII EVENTS OF DEFAULT..........................................................9

   SECTION 7.01         TRIGGERING EVENT...............................................9
   SECTION 7.02         REMEDIES.......................................................9
   SECTION 7.03         ATTORNEY-IN-FACT..............................................10
   SECTION 7.04         LIABILITY FOR DEFICIENCY......................................10
</Table>

                                       -i-

<PAGE>   3

<Table>

<S>                     <C>                                                          <C>
   SECTION 7.05         REASONABLE NOTICE.............................................10
   SECTION 7.06         COLLATERAL....................................................11
   SECTION 7.07         NON-JUDICIAL ENFORCEMENT......................................11

ARTICLE VIII MISCELLANEOUS PROVISIONS.................................................11

   SECTION 8.01         NOTICES.......................................................11
   SECTION 8.02         AMENDMENTS AND WAIVERS........................................11
   SECTION 8.03         GOVERNING LAW.................................................12
   SECTION 8.04         CUMULATIVE AND OTHER RIGHTS...................................12
   SECTION 8.05         COUNTERPARTS, EFFECTIVENESS...................................12
   SECTION 8.06         CONTINUING SECURITY AGREEMENT.................................12
   SECTION 8.07         INTERCREDITOR AGREEMENT.......................................12
</Table>

                                      -ii-

<PAGE>   4

                     PLEDGE AND COLLATERAL ACCOUNT AGREEMENT

         THIS PLEDGE AND COLLATERAL ACCOUNT AGREEMENT (this agreement as it may
be amended, modified, supplemented or waived from time to time being this
"Agreement") is made and entered into as of June 18, 2001 between Wells Fargo
Bank Minnesota, National Association, as Collateral Agent and as entitlement
holder (in such capacity, the "Collateral Agent"), Wells Fargo Bank Minnesota,
National Association, as securities intermediary (in such capacity, the
"Securities Intermediary"), and Tribo Petroleum Corporation, Tri-Union
Development Corporation, Tri-Union Operating Company, and each Subsidiary
Guarantor hereafter party to this Agreement pursuant to Section 8.08 hereof, as
obligors (each an "Obligor" and collectively the "Obligors").

                                    RECITALS

         A. On the date of this Agreement and in the future, Tribo, the
Restricted Subsidiaries (including Tri-Union Development Corporation (the
"Company")) or any of them will enter into and/or guaranty Approved Hedge
Agreements; and from time to time and in the future, Tribo, the Restricted
Subsidiaries (including the Company) may enter into and/or guaranty Hedge
Liquidity Agreements.

         B. Of even date herewith, the Company, as issuer, Tribo, as parent
guarantor, and Firstar Bank, National Association, as trustee (the "Trustee"),
have executed that certain Indenture (as hereafter amended, modified,
supplemented or waived, the "Indenture") pursuant to which the Company has
issued and the Trustee has authenticated the 12.5% Senior Secured Notes due 2006
(the "Notes").

         C. To secure the Obligations of the Obligors under the Indenture
(including the payment of principal of, premium, if any, and interest on the
Notes), each Approved Hedge Agreement, the Guaranty Agreement, and each Hedge
Liquidity Agreement (the "Obligations") (the Approved Hedge Agreements, the
Hedge Liquidity Agreement, the Guaranty Agreement and the Indenture collectively
being the "Principal Agreements"), the Obligors have agreed to pay and deposit
certain funds into an account established by the Collateral Agent, and grant to
the Collateral Agent a Lien on such account and the amounts deposited or
financial assets credited thereto.

         D. Therefore, for good and valuable consideration, the receipt and
sufficiency of which are hereby acknowledged, the parties agree as follows:

                                   ARTICLE I
                                   DEFINITIONS

         Section 1.01 Terms Defined Above; Indenture and Intercreditor Terms. As
used in this Agreement (including the Recitals), the terms defined above shall
have the meanings respectively assigned to them and capitalized terms not
defined above or in Section 1.02 shall have the meaning set forth in the
Indenture or that certain Intercreditor and Collateral Agency Agreement (as
amended, restated, modified or supplemented from time to time, the

                                      -1-
<PAGE>   5

"Intercreditor Agreement") of even date herewith, among the Obligors, each of
the Obligors now or hereafter signatory thereto, each of the Approved Hedge
Counterparties and Hedge Liquidity Providers now or hereafter signatory thereto,
Wells Fargo Bank Minnesota, National Association, as Collateral Agent, and the
Trustee.

         Section 1.02 Certain Definitions. As used in this Agreement (including
the Recitals), the following terms shall have the following meanings, unless the
context otherwise requires:

         "Collateral" shall mean the following types or items of property
whether now owned or existing or hereafter arising or acquired: (a) the
Collateral Account; (b) all property of every kind and character, including all
financial assets and securities entitlements, from time to time carried in,
credited to or held by the Securities Intermediary in, the Collateral Account,
including all United States Treasury Bills, shares of stock, all certificates of
deposit, and all cash or monies; (c) all rights, property interests and security
entitlements of the Obligors with respect to the properties described in this
definition; (d) (i) all instruments or certificates, if any, representing the
property described in this definition, (ii) all dividends (cash or otherwise),
rights to subscribe, purchase or sell, and all other rights and property from
time to time received, receivable or otherwise distributable in respect of or in
exchange for any property described in this definition, (iii) all replacements,
additions to, and substitutions for any property described in this definition,
including rights against third parties, and (iv) all proceeds, profits, interest
and other income of or on any of the property described in this definition; (e)
all books and records related to the property described in this definition; (f)
any assets or property pursuant to which a Lien is granted under Section 2.02
hereof; and (g) all proceeds of any of the foregoing.

         "Collateral Account" means securities account no. 11230600 maintained
at the Securities Intermediary or its agent or designee, including any successor
account thereto, styled the "Tri-Union Collateral Account".

         "Creditor" shall mean the Trustee, each Holder, each Approved Hedge
Counterparty and each Hedge Liquidity Provider.

         "Event of Default" shall have the meaning set forth in Section 7.01.

         "New York UCC" means the Uniform Commercial Code as presently in effect
in the State of New York. Unless otherwise provided herein, all terms which are
defined in the New York UCC and not otherwise defined herein (including the
terms "securities intermediary," "security entitlement," "financial asset,"
"entitlement holder," "securities account," "entitlement order," and "control")
shall have their respective meanings as used in Chapters 8 and 9 of the New York
UCC.

         Section 1.03 Rules of Construction. This Agreement is subject to the
same rules of construction which are set forth in Section 1.04 of the Indenture,
which section is incorporated herein by reference.

                                      -2-

<PAGE>   6

                                   ARTICLE II
                                SECURITY INTEREST

         Section 2.01 Pledge. Each Obligor hereby pledges, assigns, and grants
to the Collateral Agent a security interest in and right of set-off against all
of its right, title and interest in and to the Collateral to secure the prompt
payment and performance of the Obligations and the performance by the Obligors
of this Agreement.

         Section 2.02 Transfer of Collateral. The Obligor agrees that if (a) any
portion of the Collateral shall ever be evidenced by a certificate or instrument
and (b) such certificates or instruments representing or evidencing a portion of
the Collateral cannot be held in, carried in or credited to the Collateral
Account, then it shall deliver such certificates or instruments to the
Collateral Agent who shall hold them pursuant hereto and which certificates or
instruments shall be endorsed to the Collateral Agent or endorsed in blank by an
effective endorsement. Notwithstanding the preceding sentence, all such
certificates or instruments must be delivered or transferred in such manner as
to permit the Collateral Agent to be a "protected purchaser" to the extent of
its security interest as provided in Section 8-303 of the New York UCC and to
have "control" of such certificates or instruments as provided in Section 8-106
of the New York UCC. The Collateral Agent shall have the right, at any time in
its discretion and without notice to any Obligor, to transfer to or to register
in the name of the Collateral Agent or any of its nominees any or all of such
certificates or instruments. In addition, the Collateral Agent shall have the
right at any time to exchange certificates or instruments for certificates or
instruments of smaller or larger denominations.

                                  ARTICLE III
                             THE COLLATERAL ACCOUNT

         Section 3.01 Establishment and Character of Collateral Account. The
Securities Intermediary hereby acknowledges and agrees that it has established
the Collateral Account in the name of the Collateral Agent, on behalf of the
Creditors, which account is under the sole dominion and control of the
Collateral Agent, but otherwise belonging to the Obligors. The Securities
Intermediary hereby further agrees that (i) the Collateral Account is and shall
be maintained by the Securities Intermediary as a "securities account" (within
the meaning of Section 8-501 of the New York UCC), (B) the "securities
intermediary's jurisdiction" (within the meaning of Article 8 of the New York
UCC) of the Securities Intermediary is the State of Minnesota, (C) all cash and
other property in the Collateral Account will be treated by the Securities
Intermediary as a "financial asset" (as defined in Section 8-102(a)(9) of the
New York UCC) for the purposes of Article 8 of the New York UCC, (D) the
"entitlement holder" (as such term is defined in Section 8-102(a)(7) of the New
York UCC) for the purposes of Article 8 of the New York UCC shall be the
Collateral Agent, for the benefit of the Creditors, (E) any financial asset in
registered form or payable to, or to order of, a Person, and credited to the
Collateral Account shall be registered in the name of, payable to or to the
order of, or specially endorsed to, the Securities Intermediary or in blank, or
credited to another securities account maintained in the name of the Securities
Intermediary, and in no case shall any financial assets credited to the
Collateral Account be registered in the name of, payable to or to the order of,
or specially endorsed to, the Obligors or any of their Affiliates except to the
extent the foregoing have been

                                      -3-

<PAGE>   7

specially endorsed by the Obligors or such Affiliates to the Securities
Intermediary or in blank, (F) the Securities Intermediary shall not change the
name or account number of the Collateral Account without the prior written
consent of the Collateral Agent and at least five Business Days prior notice to
any Obligor and the Collateral Agent, and shall not change the entitlement
holder, and (G) the Securities Intermediary shall act as a "securities
intermediary" (within the meaning of Section 8-102(a)(14) of the New York UCC)
in maintaining the Collateral Account and shall credit to the Collateral Account
each financial asset to be held in or credited to the Collateral Account
pursuant to the Indenture. The Securities Intermediary will send copies of all
statements, confirmations and other correspondence concerning the Account
simultaneously to each Obligor and the Collateral Agent at their addresses set
forth in Section 8.01.

         Section 3.02 The Securities Intermediary; Etc. The Account shall remain
at all times with a securities intermediary having a combined capital and
surplus of at least $250,000,000 and having a long-term debt rating of at least
"A3" by Moody's and at least "A-" by S&P. If the Securities Intermediary fails
to have either such rating, it agrees it shall promptly resign and transfer the
Collateral Account to another Person who is qualified to act as a securities
intermediary under the New York UCC and who has the requisite credit rating. The
Securities Intermediary may change the location of the Collateral Account;
provided that (i) the Securities Intermediary give the Collateral Agent ten (10)
Business Days prior written notice thereof; and (ii) the Securities Intermediary
deliver an opinion of counsel that no adverse consequences to the existence,
perfection or priority of the Lien created hereunder will result from the
change. Any income received by the Collateral Agent with respect to the balance
from time to time on deposit in the Collateral Account, including any interest
or capital gains on investments in overnight securities made with amounts on
deposit in the Collateral Account, shall be credited to the Collateral Account.
All right, title and interest in and to the cash amounts on deposit from time to
time in the Collateral Account together with any investments in overnight
securities from time to time made pursuant to this Article III shall constitute
part of the Collateral and shall be held for the benefit of the Creditors,
Collateral Agent and the Obligors as their interests shall appear hereunder and
shall not constitute payment of the Obligations (or any other obligations to
which such funds are provided hereunder to be applied) until applied thereto as
hereinafter provided.

         Section 3.03 Investment Direction and Control.

         (a) Prior to the occurrence and continuation of an Event of Default,
the Obligors may from time to time direct the Securities Intermediary to (i)
invest cash carried or held in the Collateral Account in Temporary Cash
Investments, or (ii) to liquidate investments held in the Collateral Account and
re-invest such investments in other Temporary Cash Investments; provided,
however, (A) all such investments in United States Treasury Bills shall be made
on a payment-versus-delivery basis, (B) if the Collateral Agent or any Obligor
otherwise directs the Securities Intermediary that an Event of Default has
occurred and is continuing, the Obligors' right to direct investments shall
cease and the Securities Intermediary shall no longer take direction from any
Obligor. Except as expressly set forth in the preceding sentence, only the
Collateral Agent (and not the Obligors) shall have the right to give entitlement
orders, directions and instructions to the Securities Intermediary regarding the
Collateral.

                                      -4-

<PAGE>   8

         Anything herein to the contrary notwithstanding, each Obligor
irrevocably agrees that the Securities Intermediary may, and the Securities
Intermediary agrees that it shall, comply with "entitlement orders" (as defined
in Section 8-102(8) of the New York UCC) originated by the Collateral Agent and
relating to the Collateral Account (and all securities entitlements within the
meaning of Section 8-102(a)(17) of the New York UCC carried in the Collateral
Account) without further consent by the Obligors, any of its Restricted
Subsidiaries or any other Person so long as the Principal Agreements are in
effect. If there is any conflict between the entitlement orders originated by
Tribo, any Restricted Subsidiary or any other Person (other than the Collateral
Agent) and the entitlement orders originated by the Collateral Agent, the latter
shall control. The Collateral Agent and the Securities Intermediary hereby
represent that they have not, and hereby agree that they will not, enter into
any agreement or take any action which gives any Person other than the
Collateral Agent "control" (as defined in Section 8-106 of the New York UCC)
over the Collateral Account.

         (b) Until the Stated Maturity, neither Tribo nor any Restricted
Subsidiary shall have any rights to withdraw cash or other property held in or
credited to the Collateral Account, except as contemplated by Section 3.03 of
the Intercreditor Agreement.

         (c) The Collateral Agent shall make or direct the Securities
Intermediary to make, to the extent required or authorized hereunder,
withdrawals from the Collateral Account to make required payments to or on
behalf of the Obligors in compliance with the provisions of the Principal
Agreements.

         (d) Unless otherwise specified in this Article III, any and all cash
funds on deposit in the Collateral Account shall be invested by the Collateral
Agent in Temporary Cash Investments at the direction of the Obligors if not
withdrawn on the day of deposit in accordance with the Intercreditor Agreement.

         Section 3.04 Subordination of Securities Intermediary Lien. In the
event that the Securities Intermediary has or subsequently obtains by agreement,
operation of law or otherwise a security interest in the Collateral Account, or
any "financial asset" (as defined in Section 8-102(a)(9) of the New York UCC)
credited thereto, or any "securities entitlement" (as defined in Section
8-102(a)(17) of the New York UCC) with respect thereto, the Securities
Intermediary hereby agrees that such security interest shall be subordinate to
any and all Liens of the Collateral Agent. The financial assets (as defined in
Section 8-102(a)(9) of the New York UCC) or any "securities entitlement" (as
defined in Section 8-102(a)(17) of the New York UCC) with respect thereto,
standing to the credit the Collateral Account will not be subject to deduction,
set-off, banker's lien, or any other right in favor of any Person other than the
Collateral Agent (except the face amount of any checks which have been credited
to the Collateral Account but are subsequently returned unpaid because of
uncollected or insufficient funds).

         Section 3.05 No Other Agreements. In the event of any conflict between
this Article III (or any portion thereof), any provision of the Principal
Agreements, any Security Document or any other agreement now existing or
hereafter entered into, the terms of this Article III shall prevail.

                                      -5-

<PAGE>   9

         Section 3.06 Treasury Bills. The parties agree that all financial
assets consisting of United States Treasury securities shall be deposited and
held in an appropriate account of the Securities Intermediary maintained at a
Federal Reserve Bank in accordance with United States Treasury Regulations
relating to book-entry Treasury securities. Such Treasury securities shall be
credited by the Securities Intermediary to the Collateral Account.

                                   ARTICLE IV
                         REPRESENTATIONS AND WARRANTIES

         In order to induce the Collateral Agent to accept this Agreement, each
Obligor represents and warrants to the Collateral Agent (which representations
and warranties will survive the creation of the Obligations) that:

         Section 4.01 Ownership of Collateral; Encumbrances. Each Obligor is and
will be the legal and beneficial owner of the Collateral free and clear of any
Lien, except for the security interest created by this Agreement; and each
Obligor has full right, power, and authority to pledge, assign, and grant a
security interest in the Collateral to the Collateral Agent.

         Section 4.02 No Required Consent. No authorization, consent, approval,
or other action by, and no notice to or filing with (excluding the filing of any
financing statement pursuant to Section 5.03 hereof ), any governmental
authority or regulatory body is required for (i) the due execution, delivery and
performance by each Obligor of this Agreement, (ii) the grant by each Obligor of
the security interest granted by this Agreement, (iii) the perfection of such
Lien or (iv) the exercise by the Collateral Agent of its rights and remedies
under this Agreement.

         Section 4.03 First Priority Security Interest. The pledge of the
Collateral pursuant to this Agreement creates a valid and perfected first
priority security interest in the Collateral, enforceable against each Obligor
and all third parties and securing payment of the Obligations except as such
enforceability may be limited by bankruptcy, insolvency, reorganization,
moratorium and other similar laws now or hereinafter in effect relating to or
affecting creditors' rights generally, by general equitable principles
(regardless of whether such enforceability is considered in a proceeding in
equity or at law) or the discretion of the court before which any proceeding
therefor may be brought.

         Section 4.04 Collateral. All statements or other information provided
by the Obligor to the Collateral Agent describing or with respect to the
Collateral is or (in the case of subsequently furnished information) will be
when provided correct and complete in all material respects. The delivery at any
time by any Obligor to the Collateral Agent or the Securities Intermediary for
credit to the Collateral Account of additional Collateral or of additional
descriptions of Collateral shall constitute a representation and warranty by
such Obligor to the Collateral Agent hereunder that the representations and
warranties of this Article IV are correct insofar as they would pertain to such
Collateral or the descriptions thereof.

         Section 4.05 Chief Executive Office; Principal Place of Business;
Jurisdiction of Formation. The chief executive office, principal place of
business, legal name and jurisdiction of formation of each Obligor is as set
forth in the Indenture.

                                      -6-

<PAGE>   10

         Section 4.06 Due Authorization, Etc. This Agreement has been duly
authorized, executed and delivered by each Obligor.

                                   ARTICLE V
                            COVENANTS AND AGREEMENTS

         Each Obligor will at all times comply with the covenants and agreements
contained in this Article V, from the date hereof and for so long as any part of
the Obligations are outstanding:

         Section 5.01 Sale, Disposition or Encumbrance of Collateral. The
Obligors will not in any way encumber any of the Collateral (or permit or suffer
any of the Collateral to be encumbered) or sell, pledge, assign, lend or
otherwise dispose of or transfer (except as provided in Section 3.03(a)) of the
Collateral to or in favor of any Person other than the Collateral Agent.

         Section 5.02 Further Assurances. The Obligors shall (at the Obligors'
expense) comply with Section 6.13 of the Intercreditor Agreement with respect to
the Collateral and this Agreement. The Obligors shall also execute and deliver
all such assignments, certificates, instruments, securities, financing
statements, endorsements, requests and instructions to register transfer
(including transfer by fed-wire), notifications to financial intermediaries,
securities intermediaries (including the Securities Intermediary) clearing
corporations, issuers of securities or certificates of deposit or other third
parties, or other documents and give further assurances and do all other acts
and things as the Collateral Agent or Securities Intermediary may reasonably
request or as may be advised by an opinion of counsel are reasonably necessary
or desirable to perfect and maintain as first priority the Collateral Agent's
interest in and control of the Collateral, and to protect, enforce, or otherwise
effect the Collateral Agent's rights and remedies hereunder.

         Section 5.03 Financing Statement. The Obligors shall execute and file a
financing statement or financing statements describing the Collateral to the
extent necessary to perfect the Lien in the Collateral created by the Security
Documents.

         Section 5.04 Records and Information. Each Obligor shall keep accurate
and complete records of the Collateral (including proceeds, payments,
distributions, income and profits). The Collateral Agent may upon reasonable
prior notice at any reasonable time have access to, examine, audit, make
extracts from and inspect without hindrance or delay the Obligors' records,
files and the Collateral. Upon the request of Collateral Agent, each Obligor
will promptly provide written notice to the Collateral Agent of all information
which in any way relates to or affects the filing of any financing statement or
other public notices or recordings, or the delivery and possession of items of
Collateral for the purpose of perfecting a security interest in the Collateral.

                                      -7-

<PAGE>   11

                                   ARTICLE VI
               RIGHTS, DUTIES, AND POWERS OF THE COLLATERAL AGENT

         The following rights, duties and powers of the Collateral Agent are
applicable irrespective of whether an Event of Default occurs and is continuing:

         Section 6.01 Discharge Encumbrances. The Collateral Agent may, at its
option, discharge any taxes and Lien at any time levied or placed on the
Collateral. The Obligors agree to reimburse the Collateral Agent upon demand for
any payment so made.

         Section 6.02 Cumulative and Other Rights. The rights, powers and
remedies of the Collateral Agent hereunder are in addition to all rights,
powers, and remedies given by law, in equity, under the Principal Agreements or
any Security Document but in the event of any conflict amongst the provisions of
said documents, the terms of the Intercreditor Agreement shall govern. The
exercise by the Collateral Agent of any one or more of the rights, powers, and
remedies herein shall not be construed as a waiver of any other rights, powers,
and remedies, including, without limitation, any other rights of set-off.

         Section 6.03 Disclaimer of Certain Duties.

         (a) The powers conferred upon the Collateral Agent by this Agreement
are to protect the Collateral Agent's interest in the Collateral and shall not
impose any duty upon the Collateral Agent to exercise any such powers. Each
Obligor hereby agrees that the Collateral Agent shall not be liable for, nor
shall the Obligations be diminished by, the Collateral Agent's delay or failure
to collect upon, foreclose, sell, take possession of, or otherwise obtain value
for the Collateral.

         (b) The Collateral Agent shall be under no duty whatsoever to make or
give any presentment, notice of dishonor, protest, demand for performance,
notice of non-performance, notice of intent to accelerate, notice of
acceleration, or other notice or demand in connection with any Collateral or the
Obligations, or to take any steps necessary to preserve any rights against any
obligor on any Collateral or against any other Person. Each Obligor waives any
right of marshaling in respect of any and all Collateral, and waives any right
to require the Collateral Agent to exhaust any Collateral or enforce any other
remedy which the Collateral Agent now has or may hereafter have against such an
obligor or other Person.

         Section 6.04 Custody and Preservation of the Collateral. If the
Collateral Agent takes possession of any Collateral, the Collateral Agent shall
be deemed to have exercised reasonable care in the custody and preservation of
the Collateral in its possession if the Collateral is accorded treatment
substantially equal to that which comparable secured parties accord comparable
collateral, it being understood and agreed, however, that the Collateral Agent
shall have no responsibility for: (i) ascertaining or taking action with respect
to calls, conversions, exchanges, maturities, tenders, or other matters relative
to any Collateral, whether or not the Collateral Agent has or is deemed to have
knowledge of such matters, or (ii) taking any necessary steps to preserve rights
against Persons with respect to any Collateral.

                                      -8-

<PAGE>   12

                                  ARTICLE VII
                                EVENTS OF DEFAULT

         Section 7.01 Triggering Event. The occurrence and continuance of a
Triggering Event under the Intercreditor Agreement shall constitute an "Event of
Default" hereunder.

         Section 7.02 Remedies. Upon the occurrence and during the continuance
of any Event of Default, the Collateral Agent may, in accordance with the terms
of the Intercreditor Agreement and the Principal Agreements, take any or all of
the following actions without notice or demand to any Obligor (except where
expressly required below or pursuant to the Intercreditor Agreement):

         (a) sell, in one or more sales and in one or more parcels, or otherwise
dispose of any or all of the Collateral in any commercially reasonable manner as
the Collateral Agent may elect and in accordance with the New York UCC, in a
public or private transaction, at any location as deemed reasonable by the
Collateral Agent either for cash or credit or for future delivery at such price
as the Collateral Agent may deem fair, and (unless prohibited by the New York
UCC), the Collateral Agent may be the purchaser of any or all Collateral so sold
and may apply upon the purchase price therefor any Obligations secured hereby.
Any such sale or transfer by the Collateral Agent either to itself or to any
other Person shall be absolutely free from any claim of right by any Obligor,
including any equity or right of redemption, stay, or appraisal which any
Obligor has or may have under any rule of law, regulation, or statute now
existing or hereafter adopted. Upon any such sale or transfer, the Collateral
Agent shall have the right to deliver, assign, and transfer to the purchaser or
transferee thereof the Collateral so sold or transferred. If the Collateral
Agent deems it advisable to do so, it may restrict the bidders or purchasers of
any such sale or transfer to Persons who will represent and agree that they are
purchasing the Collateral for their own account and not with the view to the
distribution or resale of any of the Collateral. The Collateral Agent may, at
its discretion, provide for a public sale, and any such public sale shall be
held at such time or times within ordinary business hours and at such place or
places as the Collateral Agent may fix in the notice of such sale. The
Collateral Agent shall not be obligated to make any sale pursuant to any such
notice. The Collateral Agent may, without notice or publication, adjourn any
public or private sale by announcement at any time and place fixed for such
sale, and such sale may be made at any time or place to which the same may be so
adjourned. In the event any sale or transfer hereunder is not completed or is
defective in the opinion of the Collateral Agent, such sale or transfer shall
not exhaust the rights of the Collateral Agent hereunder, and the Collateral
Agent shall have the right to cause one or more subsequent sales or transfers to
be made hereunder. If only part of the Collateral is sold or transferred such
that the Obligations remain outstanding (in whole or in part), the Collateral
Agent's rights and remedies hereunder shall not be exhausted, waived, or
modified, and the Collateral Agent is specifically empowered to make one or more
successive sales or transfers until all the Collateral shall be sold or
transferred or all the Obligations are paid. In the event that the Collateral
Agent elects not to sell the Collateral, the Collateral Agent retains its rights
to dispose of or utilize the Collateral or any part or parts thereof in any
manner authorized or permitted by law or in equity, and to apply the proceeds of
the same towards payment of the Obligations. To the extent permitted by the New
York UCC, each and every method of disposition of the Collateral

                                       -9-

<PAGE>   13

described in this subsection or in subsection (c) shall constitute disposition
in a commercially reasonable manner;

         (b) apply proceeds of the disposition of the Collateral to the
Obligations in any manner elected by the Collateral Agent and permitted by the
New York UCC or otherwise (but subject to Section 2.03 of the Intercreditor
Agreement) permitted by law or in equity which application may include, without
limitation, the reasonable attorneys' fees and legal expenses incurred by the
Collateral Agent;

         (c) appoint any Person as agent to perform any act or acts necessary or
incident to any sale or transfer by the Collateral Agent of the Collateral;

         (d) and to execute, assign, and endorse negotiable and other
instruments for the payment of money, documents of title, or other evidences of
payment, shipment, or storage for any form of Collateral on behalf of and in the
name of any Obligor;

         (e) exercise all rights under this Agreement and provide to the
Securities Intermediary such entitlement orders, directives, instructions for
transfer and delivery of the Collateral, and take such other actions, in each
case as may be necessary for the Collateral Agent to exercise its rights
hereunder; and

         (f) exercise all other rights and remedies permitted by law or in
equity.

         Section 7.03 Attorney-in-Fact. Each Obligor hereby irrevocably appoints
the Collateral Agent as its attorney-in-fact, with full authority in the place
and stead of such Obligor and in the name of such Obligor or otherwise, from
time to time in the Collateral Agent's discretion upon the occurrence and during
the continuance of an Event of Default, but at such Obligor's cost and expense
and without notice to such Obligor, to take any action and to execute any
assignment, certificate, financing statement, stock power, notification,
document, or instrument which the Collateral Agent may deem necessary or
advisable to accomplish the purposes of this Agreement, including, without
limitation, to receive, endorse, and collect all instruments made payable to
such Obligor representing any dividend, interest payment, or other distribution
in respect of the Collateral or any part thereof and to give full discharge for
the same. The foregoing power-of-attorney is coupled with an interest and is
irrevocable.

         Section 7.04 Liability for Deficiency. If any sale or other disposition
of Collateral by the Collateral Agent or any other action of the Collateral
Agent hereunder results in reduction of the Obligations, such action will not
release any Obligor from its liability for any unpaid Obligations, including
reasonable costs, charges, and expenses incurred in the liquidation of
Collateral unless provided otherwise under the New York UCC, and the same shall
be immediately due and payable to the Collateral Agent, for its benefit and the
benefit of the Creditors, at the Collateral Agent's address set forth in the
Intercreditor Agreement.

         Section 7.05 Reasonable Notice. If any applicable provision of any law
requires the Collateral Agent to give reasonable notice of any sale or
disposition or other action, each Obligor hereby agrees that ten (10) days'
prior written notice shall constitute reasonable notice thereof.

                                      -10-

<PAGE>   14

Such notice, in the case of public sale, shall state the time and place fixed
for such sale and, in the case of private sale, the date after which such sale
is to be made.

         Section 7.06 Collateral. Upon the occurrence and during the continuance
of an Event of Default, the Collateral Agent may exercise any and all rights of
conversion, exchange, subscription, or any other rights, privileges, or options
pertaining to any of the Collateral as if it were the absolute owner thereof
without liability except for its gross negligence or willful misconduct and to
account for property actually received by it, but the Collateral Agent shall
have no duty to exercise any rights, privileges or options and shall not be
responsible for any failure to do so or delay in so doing.

         Section 7.07 Non-judicial Enforcement. The Collateral Agent may enforce
its rights hereunder without prior judicial process or judicial hearing unless
required by the New York UCC, and to the extent permitted by law each Obligor
expressly waives any and all legal rights which might otherwise require the
Collateral Agent to enforce its rights by judicial process.

                                  ARTICLE VIII
                            MISCELLANEOUS PROVISIONS

         Section 8.01 Notices. All notices and other communications provided for
hereunder shall be made in accordance with the terms of the Intercreditor
Agreement, if to any Obligor or the Collateral Agent, at the address or
telecopier number set forth therein, and if to the Securities Intermediary, at
its address or telecopier number set forth below:

                  Wells Fargo Bank Minnesota, N.A.
                  Corporate Trust
                  Sixth and Marquette Avenue
                  MAC N9303-120
                  Minneapolis, MN 55479
                  Attention: Tri-Union Administrator
                  Telecopier: (612) 667-9825

or, as to each party, at such other address as shall be designated by such party
in a written notice to the other parties.

         Section 8.02 Amendments and Waivers. Any forbearance, failure, or delay
by the Collateral Agent in exercising any right, power, or remedy hereunder
shall not be deemed a waiver of any obligation of any Obligor or of any right,
power, or remedy of the Collateral Agent; and no partial exercise of any right,
power, or remedy shall preclude any other or further exercise thereof. Each
Obligor hereby agrees that if the Collateral Agent agrees to a waiver of any
provision hereunder or an exchange of or release of the Collateral, any such
action shall not constitute a waiver of any of the Collateral Agent's other
rights or of any Obligor's obligations hereunder. This Agreement may be amended
only by an instrument in writing executed jointly by the Obligors and the
Collateral Agent as set forth in the Intercreditor Agreement.

                                      -11-

<PAGE>   15

         Section 8.03 Governing Law. This Agreement shall be governed by and
construed in accordance with the laws of the State of New York.

         Section 8.04 Cumulative and Other Rights. The rights, powers and
remedies of the Collateral Agent hereunder are in addition to all rights,
powers, and remedies given by law or in equity or pursuant to any other
agreement between the Collateral Agent and the Obligors with respect to the
Obligations or this Agreement. The exercise by the Collateral Agent of any one
or more of the rights, powers, and remedies herein shall not be construed as a
waiver of any other rights, powers, and remedies, including, without limitation,
any other rights of set-off.

         Section 8.05 Counterparts, Effectiveness. This Agreement may be
executed in two or more counterparts. Each counterpart is deemed an original,
but all such counterparts taken together constitute one and the same instrument.

         Section 8.06 Continuing Security Agreement.

         (a) Except as may be expressly applicable pursuant to Section 9-505 of
the New York UCC, no action taken or omission to act by the Collateral Agent
hereunder shall be deemed to constitute a retention of the Collateral in
satisfaction of the Obligations or otherwise to be in full satisfaction of the
Obligations, and the Obligations shall remain in full force and effect, until
the Collateral Agent shall have applied payments (including, without limitation,
collections from Collateral) towards the Obligations in the full amount then
outstanding or until such subsequent time as is hereinafter provided in
subsection (b) below.

         (b) To the extent that any payments on the Obligations or proceeds of
the Collateral are subsequently invalidated, declared to be fraudulent or
preferential, set aside, or required to be repaid to a trustee, debtor in
possession, receiver, or other Person under any bankruptcy law, common law, or
equitable cause, then to such extent the Obligations so satisfied shall be
revived and continue as if such payment or proceeds had not been received by the
Collateral Agent and the Collateral Agent's security interests, rights, powers,
and remedies hereunder shall continue in full force and effect.

         Section 8.07 Intercreditor Agreement. All of the rights of any of the
parties hereunder are subject to the limitations, terms and conditions set forth
in the Intercreditor Agreement.

         Section 8.08 Additional Obligors. Each Subsidiary Guarantor that is
required to become a party to this Pledge and Collateral Account Agreement shall
become an Obligor for all purposes of this Agreement upon execution and delivery
by such Subsidiary of a Supplemental Pledge and Collateral Account Agreement in
the form of Annex 1 hereto.

     [REMAINDER OF PAGE INTENTIONALLY LEFT BLANK. SIGNATURE PAGE(S) FOLLOW.]

                                      -12-

<PAGE>   16

         IN WITNESS WHEREOF, the undersigned has caused this Agreement to be
duly executed and delivered by its duly authorized officer on the day and year
first above written.

OBLIGORS:                       TRI-UNION DEVELOPMENT CORPORATION

                                By:
                                   ---------------------------------------------
                                   Name:  Richard Bowman
                                   Title: President and Chief Executive Officer

                                TRIBO PETROLEUM CORPORATION

                                By:
                                   ---------------------------------------------
                                   Name:  Richard Bowman
                                   Title: President and Chief Executive Officer

                                TRI-UNION OPERATING COMPANY

                                By:
                                   ---------------------------------------------
                                   Name:  Richard Bowman
                                   Title: President and Chief Executive Officer

          [Pledge and Collateral Account Agreement - Signature Page- 1]

<PAGE>   17

ENTITLEMENT HOLDER:            WELLS FARGO BANK MINNESOTA, NATIONAL ASSOCIATION,
                               as Collateral Agent

                               By:
                                  ----------------------------------------------
                                  Name:  Jane Y. Schweiger
                                  Title: Assistant Vice President

SECURITIES INTERMEDIARY:       WELLS FARGO BANK MINNESOTA, NATIONAL ASSOCIATION,
                               as Securities Intermediary

                               By:
                                  ----------------------------------------------
                                  Name:  Jane Y. Schweiger
                                  Title: Assistant Vice President

          [Pledge and Collateral Account Agreement - Signature Page- 2]

<PAGE>   18

                                     Annex 1

                                     Form of

              SUPPLEMENTAL PLEDGE AND COLLATERAL ACCOUNT AGREEMENT

         SUPPLEMENTAL PLEDGE AND COLLATERAL ACCOUNT AGREEMENT (this
"Supplemental Agreement") dated as of ____________ among

All capitalized terms used herein but not defined herein shall have the meanings
set forth in the Agreement (as defined below).

                                   WITNESSETH:

         WHEREAS, Tri-Union Development Company (the "Company"), certain of the
Company's Affiliates (other than the Additional Guarantor), the Creditors and
the Collateral Agent have entered into Approved Hedge Agreements, Hedge
Liquidity Agreements and the Indenture dated as of June 18, 2001 (as amended,
supplemented or otherwise modified from time to time, the "Indenture") (the
Approved Hedge Agreements, the Hedge Liquidity Agreement and the Indenture
collectively being the "Principal Agreements");

         WHEREAS, in connection with the Principal Agreements, certain of the
Company's Affiliates (other than the Additional Obligor) have entered into the
Pledge and Collateral Account Agreement, dated as of June 18, 2001 (as amended,
restated, supplemented or otherwise modified from time to time, the
"Agreement");

         WHEREAS, the Principal Agreements require that the Additional Obligor
become a party to the Pledge and Collateral Account Agreement; and

         WHEREAS, the Additional Obligor has agreed to execute and deliver this
Supplemental Agreement in order to become a party to the Pledge and Collateral
Account Agreement;

         NOW, THEREFORE, IT IS AGREED:

         1. Pledge and Collateral Account Agreement. By executing and delivering
this Supplemental Agreement, the Additional Obligor, as provided in Section 8.08
of the Agreement, hereby becomes a party to the Agreement as a Obligor
thereunder with the same force and effect as if originally named therein as an
Obligor and, without limiting the generality of the foregoing, hereby expressly
assumes all obligations and liabilities of an Obligor thereunder.

         2. Representations and Warranties. The Additional Obligor hereby
represents and warrants that each of the representations and warranties
contained in Article IV of the Agreement is true and correct with respect to
such Additional Obligor as if made on and as of such date.

                               [Annex 1 - Page 1]

<PAGE>   19

         3. Further Assurances. The Additional Obligor at its expense will
execute, acknowledge and deliver all such agreements and instruments and take
all such action as the Collateral Agent or the Required Creditors from time to
time may reasonably request in order to further effectuate the purposes of this
Supplemental Agreement and the Agreement and to carry out the terms hereof and
thereof.

         4. Ratification of Agreement; Supplemental Agreement Part of Agreement.
Except as expressly amended hereby, the Agreement is in all respects ratified
and confirmed and all the terms, conditions and provisions thereof shall remain
in full force and effect. This Supplemental Agreement shall form a part of the
Agreement for all purposes, and every Obligor heretofore or hereafter
authenticated and delivered shall be bound hereby.

         5. Governing Law. THIS SUPPLEMENTAL AGREEMENT SHALL BE GOVERNED BY, AND
CONSTRUED IN ACCORDANCE WITH, THE LAWS OF THE STATE OF NEW YORK BUT WITHOUT
GIVING EFFECT TO APPLICABLE PRINCIPLES OF CONFLICTS OF LAW TO THE EXTENT THAT
THE APPLICATION OF THE LAWS OF ANOTHER JURISDICTION WOULD BE REQUIRED THEREBY.

         6. Collateral Agent Makes No Representation. The Collateral Agent makes
no representation as to the validity or sufficiency of this Supplemental
Agreement, or the Agreement as amended hereby.

         7. Counterparts. The parties may sign any number of copies of this
Supplemental Agreement. Each signed copy shall be an original, but all of them
together shall represent the same agreement.

         8. Effect of Headings. The Section headings herein are for convenience
only and shall not effect the construction thereof.

         9. Address for Notices. All notices and other communications given to
the Additional Obligor under the Agreement may be given at its address or
telecopier number as follows:

         [New Obligor]
         [Address]
         Attention:
         Telecopier No.:

                               [Annex 1 - Page 2]

<PAGE>   20

         IN WITNESS WHEREOF, the parties hereto have caused this Supplemental
Agreement to be duly executed as of the date first above written.

                               [ADDITIONAL OBLIGOR]

                               By:
                                  ---------------------------------------------
                               Name:
                                    -------------------------------------------
                               Title:
                                     ------------------------------------------

                               WELLS FARGO BANK MINNESOTA, NATIONAL ASSOCIATION,
                               as Collateral Agent

                               By:
                                  ---------------------------------------------
                               Name:
                                    -------------------------------------------
                               Title:
                                     ------------------------------------------

                               WELLS FARGO BANK MINNESOTA, NATIONAL ASSOCIATION,
                               as Securities Intermediary

                               By:
                                  ---------------------------------------------
                               Name:
                                    -------------------------------------------
                               Title:
                                     ------------------------------------------

                               [Annex 1 - Page 3]

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