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                                                                   EXHIBIT 10(b)

                                 PLEDGE AGREEMENT


     THIS PLEDGE AGREEMENT (the "Pledge Agreement") is executed as of October
__, 2000 by PENDARIES PETROLEUM LTD., a New Brunswick corporation ("Debtor"),
whose address is 8 Greenway Plaza, Suite 910, Houston, Texas 77046, and ULTRA
RESOURCES, INC., a Wyoming corporation ("Secured Party") whose address is 16801
Greenspoint Park, Suite 370, Houston, Texas 77060.

     WHEREAS, Debtor, Sino-American Energy Corporation, a Texas corporation
("Borrower") and Secured Party have entered into a Credit Agreement dated of
even date herewith (as amended, modified, supplemented, or restated from time to
time, the "Credit Agreement");

     WHEREAS, the Credit Agreement requires Debtor to grant in favor of Secured
Party first priority liens in, to, and on any and all capital stock of Borrower;
and

     WHEREAS, this Pledge Agreement is integral to the transactions contemplated
by the Loan Documents, and the execution and delivery hereof is a condition
precedent to Secured Party's oligations to extend credit under the Loan
Documents.

     NOW, THEREFORE, for valuable consideration, the receipt and adequacy of
which are hereby acknowledged, Debtor and Secured Party hereby agree as follows:

     1.   REFERENCE TO CREDIT AGREEMENT.  The terms, conditions, and provisions
of the Credit Agreement are incorporated herein by reference, the same as if set
forth herein verbatim, which terms, conditions, and provisions shall continue to
be in full force and effect hereunder so long as Secured Party is obligated to
lend under the Credit Agreement and thereafter until the Obligations are paid
and performed in full.

     2.   CERTAIN DEFINITIONS.  Unless otherwise defined herein, or the context
hereof otherwise requires, each term defined in either the Credit Agreement or
the UCC is used in this Pledge Agreement with the same meaning; provided that
(a) if the definition given to such term in the Credit Agreement conflicts with
the definition given to such term in the UCC, the Credit Agreement definition
shall control to the extent legally allowable; and (b) if any definition given
to such term in Chapter 9 of the UCC conflicts with the definition given to such
term in any other chapter of the UCC, the Chapter 9 definition shall prevail.
As used herein, the following terms have the meanings indicated:

          Debtor Relief Laws means the Bankruptcy Code of the United States of
     America and all other applicable liquidation, conservatorship, bankruptcy,
     moratorium, rearrangement, receivership, insolvency, reorganization,
     fraudulent transfer or conveyance, suspension of payments, or similar laws
     from time to time in effect affecting the Rights of creditors generally.

          Collateral has the meaning set forth in Paragraph 4 hereof.

          Obligations means, collectively, (a) the "Obligations" as defined in
     the Credit Agreement and (b) all indebtedness, liabilities, and obligations
     of Debtor arising under this Pledge Agreement or any
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     Guaranty assuring payment of the Obligations; it being the intention and
     contemplation of Borrower, Debtor and Secured Party that future advances
     will be made by Secured Party to Borrower for a variety of purposes, that
     Debtor may guarantee (or otherwise become directly or contingently
     obligated with respect to) the obligations of Borrower to Secured Party,
     and that payment and repayment of all of the foregoing are intended to and
     shall be part of the Obligations secured hereby. The Obligations shall
     include, without limitation, future, as well as existing, advances,
     indebtedness, liabilities, and obligations owed by Borrower and/or Debtor
     to Secured Party arising under the Loan Documents.

          Obligor means any Person obligated with respect to any of the
     Collateral, whether as an obligor on an instrument, issuer of securities,
     or otherwise.

          Pledged Securities means, collectively, the Pledged Shares and any
other Collateral  constituting securities;

          Security Interest means the security interest granted and the pledge
     and assignment made under Paragraph 3 hereof.

          Rights means rights, remedies, powers, privileges, and benefits.

          UCC means the Uniform Commercial Code as enacted in the State of Texas
     or other applicable jurisdiction, as amended at the time in question.

     3.   SECURITY INTEREST.  In order to secure the full and complete payment
and performance of the Obligations when due, Debtor hereby grants to Secured
Party a Security Interest in all of Debtor's Rights, titles, and interests in
and to the Collateral and pledges, collaterally transfers, and assigns the
Collateral to Secured Party, all upon and subject to the terms and conditions of
this Pledge Agreement.  Such Security Interest is granted and pledge and
assignment are made as security only and shall not subject Secured Party to, or
transfer or in any way affect or modify, any obligation of Debtor with respect
to any of the Collateral or any transaction involving or giving rise thereto.

     4.   COLLATERAL.  As used herein, the term "Collateral" means the following
items and types of property:

          (a)  All present and future issued and outstanding shares of capital
     stock or other equity interests or investment securities of Borrower now
     owned or hereafter acquired by Debtor, together with all distributions
     thereon, all cash and noncash proceeds thereof, and any securities or other
     equity interests issued in substitution or replacement thereof
     (collectively, the "Pledged Shares").

          (b)  All present and future increases, profits, combinations,
     reclassifications, and substitutes and replacements for, all or part of the
     Collateral heretofore described.

     5.   REPRESENTATIONS AND WARRANTIES.  Debtor represents and warrants to
Secured Party that:

          (a)  Credit Agreement.  Certain representations and warranties in the
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     Credit Agreement are applicable to it or its assets or operations, and each
     such representation and warranty is true and correct.

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          (b)  Binding Obligation. This Pledge Agreement creates a legal, valid,
               ------------------
     and binding Lien in and to the Collateral in favor of Secured Party and
     enforceable against Debtor.  For Collateral in which the Security Interest
     may be perfected by the filing of Financing Statements (the term "Financing
     Statements" shall include the Canadian equivalent thereof), once those
     Financing Statements have been properly filed in the jurisdictions
     described on Annex A hereto, the Security Interest in that Collateral will
     be fully perfected.  Once perfected and, in the case of investment property
     or instruments, upon possession or "control" (within the meaning of
     Sections 8.106 and 9.115 of the UCC) by Secured Party, the Security
     Interest will constitute a first-priority Lien on the Collateral, subject
     only to Permitted Liens.  The creation of the Security Interest does not
     require the consent of any Person that has not been obtained.

          (c)  Location.  Debtor's place of business and chief executive office
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     is where Debtor is entitled to receive notices hereunder.

          (d)  Securities.  All Collateral that is Pledged Securities is duly
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     authorized, validly issued, fully paid, and non-assessable, and the
     transfer thereof is not subject to any restrictions, other than
     restrictions imposed by applicable securities and corporate Laws.  The
     Pledged Shares constitute one hundred percent (100%) of the issued and
     outstanding common stock or other equity interests of Borrower owned by
     Debtor.  Debtor has good title to the Collateral, free and clear of all
     Liens and encumbrances thereon (except for the Security Interest created
     hereby and inchoate tax liens), and has delivered to Secured Party all
     stock certificates, dividends in the form of promissory notes, bonds, or
     debentures, or other instruments or documents representing or evidencing
     the Collateral, together with corresponding assignment or transfer powers
     duly executed in blank by Debtor, and such powers have been duly and
     validly executed and are binding and enforceable against Debtor in
     accordance with their terms; and the pledge of the Collateral in accordance
     with the terms hereof creates a valid and perfected first priority Security
     Interest in the Collateral securing payment of the Obligations.

          (e)  Governmental Authority.  No authorization, approval, or other
               ----------------------
     action by, and no notice to or filing with, any Governmental Authority is
     required either (i) for the pledge by Debtor of the Pledged Securities
     pursuant to this Pledge Agreement or for the execution, delivery, or
     performance of this Pledge Agreement by Debtor, or (ii) for the exercise by
     Secured Party of the voting or other Rights provided for in this Pledge
     Agreement or the remedies in respect of the Collateral pursuant to this
     Pledge Agreement (other than compliance with applicable securities law).

          (f)  Liens.  Debtor owns all presently existing Collateral, and will
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     acquire all hereafter-acquired Collateral, free and clear of all Liens,
     except Permitted Liens.

The foregoing representations and warranties will be true and correct in all
material respects with respect to any additional Collateral or additional
specific descriptions of certain Collateral delivered to Secured Party in the
future by Debtor.

     The failure of any of these representations or warranties to be accurate
and complete does not impair the Security Interest in any Collateral.

     6.   COVENANTS.  So long as Secured Party is committed to extend credit to
Borrower under the Credit Agreement and until the Obligations are paid and
performed in full, Debtor covenants and agrees with Secured Party that Debtor
will:



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          (a)  Credit Agreement.  (i)  Comply with, perform, and be bound by all
               ----------------
     covenants and agreements in the Credit Agreement that are applicable to it,
     its assets, or its operations, each of which is hereby ratified and
     confirmed (INCLUDING, WITHOUT LIMITATION, THE INDEMNIFICATION AND RELATED
     PROVISIONS IN SECTION 5.18 OF THE CREDIT AGREEMENT); AND (ii) CONSENT TO
     AND APPROVE THE VENUE, SERVICE OF PROCESS, AND WAIVER OF JURY TRIAL
     PROVISIONS OF SECTIONS 8.16 AND 8.17 OF THE CREDIT AGREEMENT.

          (b)  Perform Obligations.  Fully perform all of Debtor's duties under
               -------------------
     and in connection with each transaction to which the Collateral, or any
     part thereof, relates, so that the amounts thereof shall actually become
     payable in their entirety to Secured Party.

          (c)  Notices.  (i) Promptly notify Secured Party of (A) any change in
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     any fact or circumstances represented or warranted by Debtor with respect
     to any of the Collateral or Obligations which could reasonably be expected
     to cause a Material Adverse Effect, and (B) any claim, action, or
     proceeding affecting title to all or any of the Collateral or the Security
     Interest and, at the request of Secured Party, appear in and defend, at
     Debtor's expense, any such action or proceeding; and  (ii) give Secured
     Party thirty (30) days written notice before any proposed (A) relocation of
     its principal place of business or chief executive office or (B) change of
     its name, identity, or corporate structure.  Prior to making any of the
     changes contemplated in clause (ii) preceding, Secured Party shall execute
     and deliver all such additional documents and perform all additional acts
     as Secured Party, in its sole discretion, may request in order to continue
     or maintain the existence and priority of the Security Interests in all of
     the Collateral.

          (d)  Collateral in Trust.  Hold in trust (and not commingle with other
               -------------------
     assets of Debtor) for Secured Party all Collateral that is chattel paper,
     instruments, Pledged Securities, or documents at any time received by
     Debtor, and promptly deliver same to Secured Party, unless Secured Party at
     its option (which may be evidenced only by a writing signed by Secured
     Party stating that Secured Party elects to permit Debtor to so retain)
     permits Debtor to retain the same, but any Collateral so retained shall be
     marked to state that it is assigned to Secured Party.

          (e)  Further Assurances.  At Debtor's expense and Secured Party's
               ------------------
     request, before or after a Default or Event of Default, (i) file or cause
     to be filed such applications and take such other actions as Secured Party
     may reasonably request to obtain the consent or approval of any
     Governmental Authority to Secured Party's Rights hereunder, including,
     without limitation, the Right to sell all the Collateral upon a Default or
     Event of Default without additional consent or approval from such
     Governmental Authority (other than approval required under applicable
     securities law) (and, because Debtor agrees that Secured Party's remedies
     at Law for failure of Debtor to comply with this provision would be
     inadequate and that such failure would not be adequately compensable in
     damages, Debtor agrees that its covenants in this provision may be
     specifically enforced); (ii) from time to time promptly execute and deliver
     to Secured Party all such other assignments, certificates, supplemental
     documents, and financing statements, and do all other acts or things as
     Secured Party may reasonably request in order to more fully create,
     evidence, perfect, continue, and preserve the priority of the Security
     Interest; and (iii) pay all filing fees in connection with any financing,
     continuation, or termination statement or other instrument with respect to
     the Security Interests.

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          (f)  Modifications to Agreements.  Not modify or substitute, or permit
               ---------------------------
     the modification or substitution of, any document evidencing the Collateral
     or contract to which any of the Collateral is subject.

          (g)  Securities.  Not sell, exchange, or otherwise dispose of, or
               ----------
     grant any option, warrant, or other Right with respect to, any of the
     Collateral; cause Borrower not to issue any stock, partnership interest, or
     other securities or equity interests in addition to or in substitution for
     the Pledged Securities issued by Borrower; notwithstanding the foregoing,
     pledge hereunder, immediately upon Debtor's acquisition (directly or
     indirectly) thereof, any and all additional shares of stock, partnership
     interest, or other securities or equity interests of Borrower issued to
     Debtor; and take any action necessary, required, or requested by Secured
     Party to allow Secured Party to fully enforce its Security Interest in the
     Collateral, including, without limitation, the filing of any claims with
     any court, liquidator, trustee, custodian, receiver, or other like person
     or party.

     7.   DEFAULT; REMEDIES.  If an Event of Default exists, Secured Party may,
at its election (but subject to the terms and conditions of the Credit
Agreement), exercise any and all Rights available to a Secured Party under the
UCC, in addition to any and all other Rights afforded by the Loan Documents, at
Law, in equity, or otherwise, including, without limitation, (a) applying by
appropriate judicial proceedings for appointment of a receiver for all or part
of the Collateral (and Debtor hereby consents to any such appointment), and (b)
applying to the Obligations any cash held by Secured Party under this Pledge
Agreement, if any.

          (a)  Notice.  Reasonable notification of the time and place of any
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     public sale of the Collateral, or reasonable notification of the time after
     which any private sale or other intended disposition of the Collateral is
     to be made, shall be sent to Debtor and to any other Person entitled to
     notice under the UCC; provided, that if any of the Collateral threatens to
     decline speedily in value or is of the type customarily sold on a
     recognized market, Secured Party may sell or otherwise dispose of the
     Collateral without notification, advertisement, or other notice of any
     kind.  It is agreed that notice sent or given not less than ten (10)
     Business Days prior to the taking of the action to which the notice relates
     is reasonable notification and notice for the purposes of this
     subparagraph.

          (b)  Sales of Pledged Securities.
               ---------------------------

               (i)  Debtor agrees that, because of the Securities Act of 1933,
          as amended, or the rules and regulations promulgated thereunder
          (collectively, the "Securities Act"), or any other Laws or
          regulations, and for other reasons, there may be legal or practical
          restrictions or limitations affecting Secured Party in any attempts to
          dispose of certain portions of the Pledged Securities and for the
          enforcement of its Rights. For these reasons, Secured Party is hereby
          authorized by Debtor, but not obligated, upon the occurrence and
          during the continuation of a Default or Event of Default, to sell all
          or any part of the Pledged Securities at private sale, subject to
          investment letter or in any other manner which will not require the
          Pledged Securities, or any part thereof, to be registered in
          accordance with the Securities Act or any other Laws or regulations,
          at a reasonable price at such private sale or other distribution in
          the manner mentioned above. Debtor understands that Secured Party may
          in its discretion approach a limited number of potential purchasers
          and that a sale under such circumstances may yield a lower price for
          the Pledged Securities, or any part thereof, than would otherwise be
          obtainable if such Pledged Securities were either afforded to a larger
          number of potential purchasers, registered under the Securities Act,
          or sold in the open market.  Debtor agrees that

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          any such private sale made under this Paragraph 7(b) shall be deemed
          to have been made in a commercially reasonable manner, and that
          Secured Party has no obligation to delay the sale of any Pledged
          Securities to permit the issuer thereof to register it for public sale
          under any applicable federal or state securities Laws.

               (ii)     Secured Party is authorized, in connection with any such
          sale, (A) to restrict the prospective bidders on or purchasers of any
          of the Pledged Securities to a limited number of sophisticated
          investors who will represent and agree that they are purchasing for
          their own account for investment and not with a view to the
          distribution or sale of any of such Pledged Securities, and (B) to
          impose such other limitations or conditions in connection with any
          such sale as Secured Party reasonably deems necessary in order to
          comply with applicable Law.  Debtor covenants and agrees that it will
          execute and deliver such documents and take such other action (other
          than registration under applicable securities laws) as Secured Party
          reasonably deems necessary in order that any such sale may be made in
          compliance with applicable Law.  Upon any such sale Secured Party
          shall have the Right to deliver, assign, and transfer to the purchaser
          thereof the Pledged Securities so sold.  Each purchaser at any such
          sale shall hold the Pledged Securities so sold absolutely, free from
          any claim or Right of Debtor of whatsoever kind, including any equity
          or Right of redemption of Debtor.  Debtor, to the extent permitted by
          applicable Law, hereby specifically waives all Rights of redemption,
          stay, or appraisal which it has or may have under any Law now existing
          or hereafter enacted.

               (iii)    Except where notice is not required pursuant to
          Paragraph 7(a), Debtor agrees that ten (10) Business Days' written
          notice from Secured Party to Debtor of Secured Party's intention to
          make any such public or private sale or sale at a broker's board or on
          a securities exchange shall constitute "reasonable notification"
          within the meaning of Section 9.504(c) of the UCC. Such notice shall
          (A) in case of a public sale, state the time and place fixed for such
          sale, (B) in case of sale at a broker's board or on a securities
          exchange, state the board or exchange at which such a sale is to be
          made and the day on which the Pledged Securities, or the portion
          thereof so being sold, will first be offered to sale at such board or
          exchange, and (C) in the case of a private sale, state the day after
          which such sale may be consummated. Any such public sale shall be held
          at such time or times within ordinary business hours and at such place
          or places as Secured Party may fix in the notice of such sale. At any
          such sale, the Pledged Securities may be sold in one lot as an
          entirety or in separate parcels, as Secured Party may reasonably
          determine. Secured Party shall not be obligated to make any such sale
          pursuant to any such notice. Secured Party may, without notice or
          publication, adjourn any public or private sale or cause the same to
          be adjourned from time to time by announcement at the time and place
          fixed for the sale, and such sale may be made at any time or place to
          which the same may be so adjourned.

               (iv)     In case of any sale of all or any part of the Pledged
          Securities on credit or for future delivery, the Pledged Securities so
          sold may be retained by Secured Party until the selling price is paid
          by the purchaser thereof, but Secured Party shall not incur any
          liability in case of the failure of such purchaser to take up and pay
          for the Pledged Securities so sold and in case of any such failure,
          such Pledged Securities may again be sold upon like notice.  Secured
          Party, instead of exercising the power of sale herein conferred upon
          it, may proceed by a suit or suits at law or in equity to foreclose
          the Security Interests and sell the Pledged

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          Securities, or any portion thereof, under a judgment or decree of a
          court or courts of competent jurisdiction.

               (v)  Without limiting the foregoing, or imposing upon Secured
          Party any obligations or duties not required by applicable Law, Debtor
          acknowledges and agrees that, in foreclosing upon any of the Pledged
          Securities, or exercising any other Rights provided Secured Party
          hereunder or under applicable Law, Secured Party may, but shall not be
          required to, (A) require the execution and delivery of confidentiality
          agreements or other documents and agreements as a condition to
          prospective purchasers' receipt of information regarding the Pledged
          Securities or participation in any public or private foreclosure sale
          process, (B) provide to prospective purchasers business and financial
          information regarding Debtor or the Companies available in the files
          of Secured Party at the time of commencing the foreclosure process,
          without the requirement that Secured Party obtain, or seek to obtain,
          any updated business or financial information or verify, or certify to
          prospective purchasers, the accuracy of any such business or financial
          information, or (C) offer for sale and sell the Pledged Securities
          with, or without, first employing an appraiser, investment banker, or
          broker with respect to the evaluation of the Pledged Securities, the
          solicitation of purchasers for Pledged Securities, or the manner of
          sale of Pledged Securities.

          (c)  Application of Proceeds.  Secured Party shall apply the proceeds
               -----------------------
     of any sale or other disposition of the Collateral under this Paragraph 7
     in the following order:  first, to the payment of all expenses incurred in
     retaking, holding, and preparing any of the Collateral for sale(s) or other
     disposition, in arranging for such sale(s) or other disposition, and in
     actually selling or disposing of the same (all of which are part of the
     Obligations); second, toward repayment of amounts expended by Secured Party
     under Paragraph 8; and third, toward payment of the balance of the
     Obligations in the order and manner specified in the Credit Agreement.  Any
     surplus remaining shall be delivered to Debtor or as a court of competent
     jurisdiction may direct.  If the proceeds are insufficient to pay the
     Obligations in full, Debtor shall remain liable for any deficiency.

     8.  OTHER RIGHTS OF SECURED PARTY.

          (a)  Performance.  If Debtor fails to preserve the priority of the
               -----------
     Security Interest in any of the Collateral or otherwise fails to perform
     any of its obligations under the Loan Documents with respect to the
     Collateral (not cured within any applicable cure period), then Secured
     Party may, at its option, but without being required to do so, prosecute or
     defend any suits in relation to the Collateral, or take all other material
     action which Debtor is required, but has failed or refused, to take under
     the Loan Documents.  Any sum which may be expended or paid by Secured Party
     under this subparagraph (including, without limitation, court costs and
     attorneys' fees) shall bear interest from the dates of expenditure or
     payment at the Default Rate until paid and, together with such interest,
     shall be payable by Debtor to Secured Party upon demand and shall be part
     of the Obligations.

          (b)  Collection.  If an Event of Default exists and upon notice from
               ----------
     Secured Party, each Obligor with respect to any payments on any of the
     Collateral (including, without limitation, dividends and other
     distributions with respect to Pledged Securities) is hereby authorized and
     directed by Debtor to make payment directly to Secured Party, regardless of
     whether Debtor was previously making collections thereon.  Subject to
     Paragraph 8(e) hereof, until such notice is given, Debtor is authorized to
     retain and expend all cash payments made on Collateral.  If an Event of
     Default exists, Secured Party shall have the Right in its own name or in
     the name of Debtor to compromise or extend time of

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<PAGE>

     payment with respect to all or any portion of the Collateral for such
     amounts and upon such terms as Secured Party may determine; to demand,
     collect, receive, receipt for, sue for, compound, and give acquittances for
     any and all amounts due or to become due with respect to Collateral; to
     take control of cash and other proceeds of any Collateral; to endorse the
     name of Debtor on any notes, acceptances, checks, drafts, money orders, or
     other evidences of payment on Collateral that may come into the possession
     of Secured Party; to sign the name of Debtor on any invoice or bill of
     lading relating to any Collateral, on any drafts against Obligors or other
     Persons making payment with respect to Collateral, on assignments and
     verifications of accounts or other Collateral and on notices to Obligors
     making payment with respect to Collateral; to send requests for
     verification of obligations to any Obligor; and to do all other acts and
     things necessary to carry out the intent of this Pledge Agreement. If an
     Event of Default exists and any Obligor fails or refuses to make payment on
     any Collateral when due, Secured Party is authorized, in its sole
     discretion, either in its own name or in the name of Debtor, to take such
     action as Secured Party shall deem appropriate for the collection of any
     amounts owed with respect to Collateral or upon which a delinquency exists.
     Regardless of any other provision hereof, however, Secured Party shall
     never be liable for its failure to collect, or for its failure to exercise
     diligence in the collection of, any amounts owed with respect to
     Collateral, nor shall it be under any duty whatsoever to anyone except
     Debtor to account for funds that it shall actually receive hereunder.
     Without limiting the generality of the foregoing, Secured Party shall have
     no responsibility for ascertaining any maturities, calls, conversions,
     exchanges, offers, tenders, or similar matters relating to any Collateral,
     or for informing Debtor with respect to any of such matters (irrespective
     of whether Secured Party actually has, or may be deemed to have, knowledge
     thereof). The receipt of Secured Party to any Obligor shall be a full and
     complete release, discharge, and acquittance to such Obligor, to the extent
     of any amount so paid to Secured Party.

          (c)  Record Ownership of Securities. If an Event of Default exists,
               ------------------------------
     Secured Party at any time may have any Collateral that is Pledged
     Securities and that is in the possession of Secured Party, or its nominee
     or nominees, registered in its name, or in the name of its nominee or
     nominees, as Secured Party; and, as to any Collateral that is Pledged
     Securities so registered, Secured Party shall execute and deliver (or cause
     to be executed and delivered) to Debtor all such proxies, powers of
     attorney, dividend coupons or orders, and other documents as Debtor may
     reasonably request for the purpose of enabling Debtor to exercise the
     voting Rights and powers which it is entitled to exercise under this Pledge
     Agreement or to receive the dividends and other distributions and payments
     in respect of such Collateral that is Pledged Securities or proceeds
     thereof which it is authorized to receive and retain under this Pledge
     Agreement.

          (d)  Voting of Securities.  As long as no Event of Default exists,
               --------------------
     Debtor is entitled to exercise all voting Rights pertaining to any Pledged
     Securities.  If an Event of Default exists and if Secured Party elects to
     exercise such Right, the Right to vote any Pledged Securities shall be
     vested exclusively in Secured Party.  To this end, Debtor hereby
     irrevocably constitutes and appoints Secured Party the proxy and attorney-
     in-fact of Debtor, with full power of substitution, to vote, and to act
     with respect to, any and all Collateral standing in the name of Debtor or
     with respect to which Debtor is entitled to vote and act, subject to the
     understanding that such proxy may not be exercised unless an Event of
     Default exists.  The proxy herein granted is coupled with an interest, is
     irrevocable, and shall continue until the Obligations have been paid and
     performed in full.

          (e)  Certain Proceeds.  Notwithstanding any contrary provision herein,
               ----------------
     any and all stock dividends or other Distributions in property made on or
     in respect of any Collateral, and any proceeds of any Collateral, whether
     such dividends, distributions, or proceeds result from a subdivision,

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     combination, or reclassification of the outstanding capital stock of any
     issuer thereof or as a result of any merger, consolidation, acquisition, or
     other exchange of assets to which any issuer may be a party, or otherwise,
     shall be part of the Collateral hereunder, shall, if received by Debtor, be
     held in trust for the benefit of Secured Party, and shall forthwith be
     delivered to Secured Party (accompanied by proper instruments of assignment
     and/or stock and/or bond powers executed by Debtor in accordance with
     Secured Party's instructions) to be held subject to the terms of this
     Pledge Agreement.  Any cash proceeds of Collateral which come into the
     possession of Secured Party on and after the occurrence of an Event of
     Default (including, without limitation, insurance proceeds with respect to
     the Collateral) may, at Secured Party's option, be applied in whole or in
     part to the Obligations (to the extent then due), be released in whole or
     in part to or on the written instructions of Debtor for any general or
     specific purpose, or be retained in whole or in part by Secured Party as
     additional Collateral.  Any cash Collateral in the possession of Secured
     Party may be invested by Secured Party in certificates of deposit issued by
     Secured Party (if Secured Party issues such certificates) or by any state
     or national bank having combined capital and surplus greater than
     $100,000,000 with a rating from Moody's and S&P of P-1 and A-1+,
     respectively, or in securities issued or guaranteed by the United States of
     America or any agency thereof.  Secured Party shall never be obligated to
     make any such investment and shall never have any liability to Debtor for
     any loss which may result therefrom.  All interest and other amounts earned
     from any investment of Collateral may be dealt with by Secured Party in the
     same manner as other cash Collateral.  The provisions of this subparagraph
     are applicable whether or not a Default or Event of Default exists.

          (f)  Power of Attorney. Debtor hereby irrevocably constitutes and
               -----------------
     appoints Secured Party as Debtor's attorney-in-fact, with full irrevocable
     power and authority in the place and stead of Debtor and in the name of
     Debtor, Secured Party, or otherwise, from time to time in Secured Party's
     discretion, for the sole purpose of carrying out the terms of this Pledge
     Agreement and, to the extent permitted by applicable Law, to take any
     action and to execute any document and instrument which Secured Party may
     deem necessary or advisable to accomplish the following (but only after an
     Event of Default exists with respect to clause (i) below):

               (i)    to receive, endorse, and collect any drafts or other
          instruments or documents in connection with clause (b) above and this
          clause (f); and

               (ii)   to execute on behalf of Debtor, any continuation statement
          with respect to the Security Interests created hereby, and to do any
          and all acts and things to protect and preserve the Collateral,
          including, without limitation, the protection and prosecution of all
          Rights.

          (g)  Purchase Money Collateral.  To the extent that Secured Party  has
               -------------------------
     advanced or will advance funds to or for the account of Debtor to enable
     Debtor to purchase or otherwise acquire Rights in Collateral, Secured
     Party, at its option, may pay such funds (i) directly to the Person from
     whom Debtor will make such purchase or acquire such Rights, or (ii) to
     Debtor, in which case Debtor covenants to promptly pay the same to such
     Person, and forthwith furnish to Secured Party evidence satisfactory to
     Secured Party that such payment has been made from the funds so provided.

          (h)  Subrogation. To the extent permitted by applicable Law, if any of
               -----------
     the Obligations are given in renewal or extension or applied toward the
     payment of indebtedness secured by any Lien, Secured Party shall be, and is
     hereby, subrogated to all of the Rights, titles, interests, and Liens
     securing the indebtedness so renewed, extended, or paid.

                                       9

<PAGE>

          (i)  Indemnification.  Debtor hereby assumes all liability for the
               ---------------
     Collateral, for the Security Interest, and for any use or possession of,
     all or any of the Collateral, including, without limitation, any Taxes
     arising as a result of, or in connection with, the transactions
     contemplated herein, and agrees to assume liability for, and to indemnify
     and hold Secured Party harmless from and against, any and all claims,
     causes of action, or liability, howsoever arising, from or incident to such
     use or possession, whether such Persons be agents or employees of Debtor or
     of third parties.  Debtor agrees to indemnify, save, and hold Secured Party
     harmless from and against, and covenants to defend Secured Party against,
     any and all losses, damages, claims, costs, penalties, liabilities, and
     expenses (collectively, "Claims"), including, without limitation, court
     costs and attorneys' fees, and any of the foregoing arising from the
     negligence of Secured Party, or any of their respective officers,
     employees, agents, advisors, employees, or representatives, howsoever
     arising or incurred because of, incident to, or with respect to Collateral
     or any use or possession thereof; provided, however, that the indemnity set
     forth in this Paragraph 8(i) will not apply to Claims caused by the gross
     negligence or willful misconduct of Secured Party.  Without prejudice to
     the survival of any other agreement of the Debtor hereunder, the agreements
     and obligations of the Debtor contained in this Paragraph 8(i) shall
     survive the payment in full of the Obligations.

     9.   MISCELLANEOUS.

          (a)  Continuing Security Interest.  This Pledge Agreement creates a
               ----------------------------
     continuing security interest in the Collateral and shall (i) remain in full
     force and effect until the termination of the obligations of Secured Party
     to fund Loans under the Loan Documents and the payment in full of the
     Obligations; (ii) be binding upon Debtor, its successors, and assigns; and
     (iii) inure to the benefit of and be enforceable by Secured Party and its
     respective successors, transferees, and assigns.  Without limiting the
     generality of the foregoing clause (iii), Secured Party may assign or
     otherwise transfer any of its respective Rights under this Pledge Agreement
     to any other Person in accordance with the terms and provisions of Section
     8.2 of the Credit Agreement, and to the extent of such assignment or
     transfer such Person shall thereupon become vested with all the Rights and
     benefits in respect thereof granted herein or otherwise to the Secured
     Party.  Upon payment in full of the Obligations and the termination of the
     commitment of Secured Party to extend credit under the Loan Documents,
     Debtor shall be entitled to the return, upon its request and at its
     expense, of such of the Collateral as shall not have been sold or otherwise
     applied pursuant to the terms hereof.

          (b)  Reference to Miscellaneous Provisions.  This Pledge Agreement is
               -------------------------------------
     one of the "Loan Documents" referred to in the Credit Agreement, and all
     provisions relating to Loan Documents set forth in Section 8 of the Credit
     Agreement, other than the provisions set forth in Section 8.15, are
     incorporated herein by reference, the same as if set forth herein verbatim.

          (c)  Term.  Upon full and final payment and performance of the
               ----
     Obligations, this agreement shall thereafter terminate upon receipt by
     Secured Party of Debtor's written notice of such termination; provided that
     no Obligor, if any, on any of the Collateral shall ever be obligated to
     make inquiry as to the termination of this Pledge Agreement, but shall be
     fully protected in making payment directly to Secured Party until actual
     notice of such total payment of the Obligations is received by such
     Obligor.

          (d)  Actions Not Releases.  The Security Interest and Debtor's
               --------------------
     obligations and Secured Party's Rights hereunder shall not be released,
     diminished, impaired, or adversely affected by the

                                      10

<PAGE>

     occurrence of any one or more of the following events: (i) the taking or
     accepting of any other security or assurance for any or all of the
     Obligations; (ii) any release, surrender, exchange, subordination, or loss
     of any security or assurance at any time existing in connection with any or
     all of the Obligations; (iii) the modification of, amendment to, or waiver
     of compliance with any terms of any of the other Loan Documents without the
     notification or consent of Debtor, except as required therein (the Right to
     such notification or consent being herein specifically waived by Debtor);
     (iv) the insolvency, bankruptcy, or lack of corporate or trust power of any
     party at any time liable for the payment of any or all of the Obligations,
     whether now existing or hereafter occurring; (v) any renewal, extension, or
     rearrangement of the payment of any or all of the Obligations, either with
     or without notice to or consent of Debtor, or any adjustment, indulgence,
     forbearance, or compromise that may be granted or given by Secured Party to
     Borrower or to Debtor; (vi) any neglect, delay, omission, failure, or
     refusal of Secured Party to take or prosecute any action in connection with
     any other agreement, document, guaranty, or instrument evidencing,
     securing, or assuring the payment of all or any of the Obligations; (vii)
     any failure of Secured Party to notify Debtor of any renewal, extension, or
     assignment of the Obligations or any part thereof, or the release of any
     Collateral or other security, or of any other action taken or refrained
     from being taken by Secured Party against Debtor or any new agreement
     between Secured Party and Debtor, it being understood that Secured Party
     shall not be required to give Debtor any notice of any kind under any
     circumstances whatsoever with respect to or in connection with the
     Obligations, including, without limitation, notice of acceptance of this
     Pledge Agreement or any Collateral ever delivered to or for the account of
     Secured Party hereunder; (viii) the illegality, invalidity, or
     unenforceability of all or any part of the Obligations against any party
     obligated with respect thereto by reason of the fact that the Obligations,
     or the interest paid or payable with respect thereto, exceeds the amount
     permitted by Law, the act of creating the Obligations, or any part thereof,
     is ultra vires, or the officers, partners, or trustees creating same acted
     in excess of their authority, or for any other reason; or (ix) if any
     payment by any party obligated with respect thereto is held to constitute a
     preference under applicable Laws or for any other reason Secured Party is
     required to refund such payment or pay the amount thereof to someone else.

          (e)  Waivers. Except to the extent expressly otherwise provided herein
               -------
     or in other Loan Documents and to the fullest extent permitted by
     applicable Law, Debtor waives (i) any Right to require Secured Party to
     proceed against any other Person, to exhaust its Rights in Collateral, or
     to pursue any other Right which Secured Party may have; (ii) with respect
     to the Obligations, presentment and demand for payment, protest, notice of
     protest and nonpayment, and notice of the intention to accelerate; and
     (iii) all Rights of marshaling in respect of any and all of the Collateral.

          (f)  Financing Statement.  Secured Party shall be entitled at any time
               -------------------
     to file this Pledge Agreement or a carbon, photographic, or other
     reproduction of this Pledge Agreement, as a financing statement, but the
     failure of Secured Party to do so shall not impair the validity or
     enforceability of this Pledge Agreement.

          (g)  Amendments.  This Pledge Agreement may be amended only by an
               ----------
     instrument in writing executed jointly by Debtor and Secured Party, and
     supplemented only by documents delivered or to be delivered in accordance
     with the express terms hereof.

          (h)  Multiple Counterparts. This Pledge Agreement has been executed in
               ---------------------
a number of identical counterparts, each of which shall be deemed an original
for all purposes and all of which constitute, collectively, one agreement; but,
in making proof of this Pledge Agreement, it shall not be necessary to produce
or account for more than one such counterpart.

                                      11

<PAGE>

          (i)  Parties Bound; Assignment. This Pledge Agreement shall be binding
               -------------------------
     on Debtor and Debtor's heirs, legal representatives, successors, and
     assigns and shall inure to the benefit of Secured Party and Secured Party's
     successors and assigns. Debtor may not, without the prior written consent
     of Secured Party, assign any Rights, duties, or obligations hereunder.

     (j)  Governing Law. This Pledge Agreement shall be deemed to be a contract
          -------------
made under and shall be construed in accordance with and governed by the laws of
the state of Texas without giving effect to principles thereof relating to
conflicts f Law; provided, however, that chapter 345 of the Texas Finance Code
(which regulates certain revolving credit loan accounts and revolving triparty
accounts) shall not apply.

                    Remainder of Page Intentionally Blank.
                         Signature Page(s) to Follow.

                                      12

<PAGE>

     EXECUTED as of the day and year first herein set forth.


                              PENDARIES PETROLEUM LTD., as Debtor



                              By:   ________________________
                              Name: ______________________
                       Title: _______________________

                                      13

<PAGE>

                              ULTRA RESOURCES, INC., as Secured Party


                              By:   _________________________________
                                    Name:  __________________________
                                    Title: __________________________