Document:

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                                                                    EXHIBIT 10.4

                       VOTING AND EXCHANGE TRUST AGREEMENT

         THIS VOTING AND EXCHANGE TRUST AGREEMENT is entered into as of February
14, 2001, by and between Oil States International, Inc., a Delaware corporation
("OSI"), 892489 Alberta Inc., an Alberta corporation ("PTI Holdco"), and
Computershare Trust Company of Canada (formerly Montreal Trust Company of
Canada), a Canadian trust company ("Trustee").

RECITALS:

A. Pursuant to a Combination Agreement dated as of July 31, 2000 by and among
OSI, HWC Energy Services, Inc., Sooner Inc. and PTI Group, Inc. ("PTI") and such
other parties referenced therein (such agreement as it may be amended or
restated is hereinafter referred to as the "Combination Agreement"), the parties
agreed that on the Effective Date (as defined in the Combination Agreement), OSI
and PTI Holdco would execute and deliver a Voting and Exchange Trust Agreement
containing the terms and conditions set forth in Exhibit D to the Combination
Agreement together with such other terms and conditions as may be agreed to by
the parties to the Combination Agreement acting reasonably.

B. Pursuant to an arrangement (the "Arrangement") effected by Articles of
Arrangement dated February 14, 2001 filed pursuant to the Business Corporations
Act (Alberta) (or any successor or other corporate statute by which PTI may in
the future be governed) (the "Act"), each issued and outstanding common share of
PTI (a "PTI Common Share"), other than those cancelled pursuant to the
Arrangement or held by OSI or by a Subsidiary of OSI, was ultimately exchanged
for Exchangeable Shares of PTI Holdco (the "Exchangeable Shares");

C. The Articles of Incorporation of PTI Holdco set forth the rights, privileges,
restrictions and conditions attaching to the Exchangeable Shares (collectively,
the "Exchangeable Share Provisions"), and a copy of such Articles of
Incorporation is attached hereto as Appendix A;

D. OSI is to provide voting rights in OSI to each holder (other than OSI and its
Subsidiaries) from time to time of Exchangeable Shares, such voting rights per
Exchangeable Share to be equivalent to the voting rights per share of OSI Common
Stock;

E. OSI is to grant to and in favor of the holders (other than OSI and its
Subsidiaries) from time to time of Exchangeable Shares the right, in the
circumstances set forth herein, to require OSI or OSI ULC to purchase from each
such holder all or any part of the Exchangeable Shares held by the holder;

F. The parties desire to make appropriate provision and to establish a procedure
whereby voting rights in OSI shall be exercisable by holders (other than OSI and
its Subsidiaries) from time to time of Exchangeable Shares by and through the
Trustee, which will hold legal title to and a share certificate in respect of
one share of OSI Special Voting Stock (the "OSI Special Voting Stock") to which
voting rights attach for the benefit of such holders of Exchangeable Shares and
whereby the rights to require OSI or, at the option of OSI, OSI ULC, to purchase
Exchangeable Shares from the holders thereof (other than OSI and its
Subsidiaries) shall be

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exercisable by such holders from time to time of Exchangeable Shares by and
through the Trustee, which will hold legal title to such rights for the benefit
of such holders;

G. These recitals and any statements of fact in this agreement are made by OSI
and PTI Holdco and not by the Trustee;

         NOW THEREFORE, in consideration of the respective covenants and
agreements provided in this agreement and for other good and valuable
consideration (the receipt and sufficiency of which are hereby acknowledged),
the parties agree as follows:

                                   ARTICLE 1
                         DEFINITIONS AND INTERPRETATION

1.1      DEFINITIONS

         In this agreement, the following terms shall have the following
meanings:

         "Act" has the meaning in the recitals hereto;

         "Aggregate Equivalent Vote Amount" means, with respect to any matter,
proposition or question on which holders of OSI Common Stock are entitled to
vote, consent or otherwise act, the product of (i) the number of shares of
Exchangeable Shares issued and outstanding and held by Holders multiplied by
(ii) the Equivalent Vote Amount.

         "Applicable Laws" has the meaning provided in Section 5.10 hereof.

         "Arrangement" has the meaning provided in the recitals hereto.

         "Automatic Exchange Rights" means the benefit of the obligation of OSI
to effect the automatic exchange of shares of OSI Common Stock for Exchangeable
Shares pursuant to Section 5.12 hereof.

         "Board of Directors" means the Board of Directors of PTI Holdco.

         "Business Day" has the meaning provided in the Exchangeable Share
Provisions.

         "Combination Agreement" has the meaning in the recitals hereto.

         "Equivalent Vote Amount" means, with respect to any matter, proposition
or question on which holders of OSI Common Stock are entitled to vote, consent
or otherwise act, the number of votes to which a holder of one share of OSI
Common Stock is entitled with respect to such matter, proposition or question.

         "Exchange Right" has the meaning provided in Section 5.1(b) hereof.

         "Exchangeable Share Consideration" has the meaning provided in the
Exchangeable Share Provisions.

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         "Exchangeable Share Price" has the meaning provided in the Exchangeable
Share Provisions.

         "Exchangeable Share Provisions" has the meaning provided in the
recitals hereto.

         "Exchangeable Shares" has the meaning provided in the recitals hereto.

         "freely tradeable", with respect to OSI Common Stock, means freely
transferable under Canadian provincial securities laws and U.S. federal and
state securities laws (pursuant to an effective resale shelf registration
statement or otherwise and assuming the reasonable cooperation of the holder or
recipient of OSI Common Stock in connection with any required resale shelf
registration statement), except to the extent restrictions arise by reason of a
person being a "control person" of OSI for the purposes of Canadian provincial
securities laws or an "affiliate" of OSI for the purposes of United States
federal or state securities laws, provided any trades in such securities are
conducted through the facilities of a stock exchange outside Canada.

         "Holder Votes" has the meaning provided in Section 4.2 hereof.

         "Holders" means the registered holders from time to time of
Exchangeable Shares, other than OSI and its Subsidiaries.

         "Insolvency Event" means the institution by PTI Holdco of any
proceeding to be adjudicated a bankrupt or insolvent or to be dissolved or
wound-up, or the consent of PTI Holdco to the institution of bankruptcy,
insolvency, dissolution or winding-up proceedings against it, or the filing of a
petition, answer or consent seeking dissolution or winding-up under any
bankruptcy, insolvency or analogous laws, including without limitation the
Companies' Creditors Arrangement Act (Canada) and the Bankruptcy and Insolvency
Act (Canada), and the failure by PTI Holdco to contest in good faith any such
proceedings commenced in respect of PTI Holdco within 15 days of becoming aware
thereof, or if so contested the adjudication that PTI Holdco is bankrupt or
insolvent or is to be dissolved or wound-up, or the consent by PTI Holdco to the
filing of any such petition or to the appointment of a receiver, or the making
by PTI Holdco of a general assignment for the benefit of creditors, or the
admission in writing by PTI Holdco of its inability to pay its debts generally
as they become due, or PTI Holdco's not being permitted, pursuant to liquidity
or solvency requirements of applicable law, to redeem any Retracted Shares
pursuant to Section 6.6 of the Exchangeable Share Provisions.

         "Liquidation Call Right" has the meaning provided in the Exchangeable
Share Provisions.

         "Liquidation Event" has the meaning provided in subsection 5.12(b)
hereof.

         "Liquidation Event Effective Time" has the meaning provided in
subsection 5.12(c) hereof.

         "List" has the meaning provided in Section 4.6 hereof.

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         "Officer's Certificate" means, with respect to OSI or PTI Holdco, as
the case may be, a certificate signed by any one of the Chairman of the Board,
the Vice-Chairman of the Board (if there be one), the President or any
Vice-President of OSI or PTI Holdco, as the case may be.

         "OSI" has the meaning in the recitals hereto.

         "OSI Common Stock" has the meaning provided in the Exchangeable Share
Provisions.

         "OSI Consent" has the meaning provided in Section 4.2 hereof.

         "OSI Meeting" has the meaning provided in Section 4.2 hereof.

         "OSI Special Voting Stock" has the meaning provided in the recitals
hereto.

         "OSI ULC" means the Subsidiary of OSI incorporated under the Companies
Act (Nova Scotia) for the purpose of delivering OSI Common Stock as provided for
in this Agreement, the Exchangeable Share Provisions or the Support Agreement.

         "PTI" has the meaning in the recitals hereto.

         "PTI Stock Options" means the outstanding options entitling the holders
to acquire upon exercise thereof up to 130,000 PTI Common Shares in the
aggregate.

         "PTI Holdco" has the meaning in the recitals hereto.

         "Person" includes an individual, body corporate, partnership, company,
unincorporated syndicate or organization, trust, trustee, executor,
administrator and other legal representative.

         "Plan of Arrangement" has the meaning provided in the Exchangeable
Share Provisions.

         "Redemption Call Right" has the meaning provided in the Exchangeable
Share Provisions.

         "Retracted Shares" has the meaning provided in Section 5.7 hereof.

         "Retraction Call Right" has the meaning provided in the Exchangeable
Share Provisions.

         "Subsidiary" has the meaning provided in the Exchangeable Share
Provisions.

         "Successor" has the meaning provided in subsection 11. 1 (a) hereof.

         "Support Agreement" means that certain support agreement made as of
even date hereof by and between OSI and PTI Holdco.

         "Trust" means the trust created by this agreement.

         "Trust Estate" means the Voting Share, any other securities, the
Exchange Right, the Automatic Exchange Rights and any money or other property
which may be held by the Trustee from time to time pursuant to this agreement.

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         "Trustee" means Computershare Trust Company of Canada (formerly
Montreal Trust Company of Canada) and, subject to the provisions of Article 10
hereof, includes any successor trustee or permitted assigns.

         "Voting Rights" means the voting rights attached to the Voting Share.

         "Voting Share" means the one share of OSI Special Voting Stock, U.S.
$0.01 par value, issued by OSI to and deposited with the Trustee, which entitles
the holder of record to a number of votes at meetings of holders of OSI Common
Stock equal to the Aggregate Equivalent Vote Amount.

1.2      INTERPRETATION NOT AFFECTED BY HEADINGS, ETC.

         The division of this agreement into articles, sections and paragraphs
and the insertion of headings are for convenience of reference only and shall
not affect the construction or interpretation of this agreement.

1.3      NUMBER, GENDER, ETC.

         Words importing the singular number only shall include the plural and
vice versa. Words importing the use of any gender shall include all genders.

1.4      DATE FOR ANY ACTION

         If any date on which any action is required to be taken under this
agreement is not a Business Day, such action shall be required to be taken on
the next succeeding Business Day.

1.5      PAYMENTS

         All payments to be made hereunder will be made without interest and
less any tax required by Canadian law to be deducted or withheld.

                                   ARTICLE 2
                              PURPOSE OF AGREEMENT

2.1 The purpose of this agreement is to create the Trust for the benefit of the
Holders, as herein provided. The Trustee will hold the Voting Share in order to
enable the Trustee to exercise the Voting Rights and will hold the Exchange
Right and the Automatic Exchange Rights in order to enable the Trustee to
exercise such rights, in each case as trustee for and on behalf of the Holders
as provided in this agreement.

                                   ARTICLE 3
                                  VOTING SHARE

3.1      ISSUANCE AND OWNERSHIP OF THE VOTING SHARE

         OSI hereby issues to and deposits with the Trustee the Voting Share to
be hereafter held of record by the Trustee as trustee for and on behalf of, and
for the use and benefit of, the

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Holders and in accordance with the provisions of this agreement. OSI hereby
acknowledges receipt from the Trustee as trustee for and on behalf of the
Holders of good and valuable consideration (and the adequacy thereof) for the
issuance of the Voting Share by OSI to the Trustee. During the term of the Trust
and subject to the terms and conditions of this agreement, the Trustee shall
possess and be vested with full legal ownership of the Voting Share and shall be
entitled to exercise all of the rights and powers of an owner with respect to
the Voting Share, provided that the Trustee shall:

         (a)  hold the Voting Share and the legal title thereto as trustee
              solely for the use and benefit of the Holders in accordance with
              the provisions of this agreement; and

         (b)  except as specifically authorized by this agreement, have no power
              or authority to sell, transfer, vote or otherwise deal in or with
              the Voting Share, and the Voting Share shall not be used or
              disposed of by the Trustee for any purpose other than the purposes
              for which this Trust is created pursuant to this agreement.

3.2      LEGENDED SHARE CERTIFICATES

         PTI Holdco will cause each certificate representing Exchangeable Shares
to bear an appropriate legend notifying the Holders of their right to instruct
the Trustee with respect to the exercise of the Voting Rights with respect to
the Exchangeable Shares held by a Holder.

3.3      SAFE KEEPING OF CERTIFICATE

         The certificate representing the Voting Share shall at all times be
held in safe keeping by the Trustee or its agent.

3.4      HOLDERS' BENEFIT

         For greater certainty, the Trustee holds the benefit of the Voting
Rights for the Holders, but all other rights in respect of the Voting Share,
including without limitation any rights to receive dividends on the Voting
Share, are for the benefit of OSI.

                                   ARTICLE 4
                            EXERCISE OF VOTING RIGHTS

4.1      VOTING RIGHTS

         The Trustee, as the holder of record of the Voting Share, shall be
entitled to all of the Voting Rights, including the right to consent to or to
vote in person or by proxy the Voting Share, on any matter, question or
proposition whatsoever that may properly come before the stockholders of OSI at
a OSI Meeting or in connection with a OSI Consent (in each case, as hereinafter
defined). The Voting Rights shall be and remain vested in and exercised by the
Trustee. Subject to Section 7.15 hereof, the Trustee shall exercise the Voting
Rights only on the basis of instructions received pursuant to this Article 4
from Holders entitled to instruct the Trustee as to the voting thereof at the
time at which a OSI Consent is sought or a OSI Meeting is held. To the extent
that no instructions are received from a Holder with respect to the Voting

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Rights to which such Holder is entitled, the Trustee shall not exercise or
permit the exercise of such Holder's Voting Rights.

4.2      NUMBER OF VOTES

         With respect to all meetings of stockholders of OSI at which holders of
shares of OSI Common Stock are entitled to vote (a "OSI Meeting") and with
respect to all written consents sought by OSI from its stockholders including
the holders of shares of OSI Common Stock (a "OSI Consent"), each Holder shall
be entitled to instruct the Trustee to cast and exercise, in the manner
instructed, a number of votes equal to the Equivalent Vote Amount for each
Exchangeable Share owned of record by such Holder on the record date established
by OSI or by applicable law for such OSI Meeting or OSI Consent, as the case may
be, (the "Holder Votes") in respect of each matter, question or proposition to
be voted on at such OSI Meeting or to be consented to in connection with such
OSI Consent.

4.3      MAILINGS TO SHAREHOLDERS

         With respect to each OSI Meeting and OSI Consent, the Trustee will mail
or cause to be mailed (or otherwise communicate in the same manner as OSI
utilizes in communications to holders of OSI Common Stock, subject to the
Trustee's ability to provide this method of communication and upon being advised
in writing of such method) to each of the Holders named in the List on the same
day as the initial mailing or notice (or other communication) with respect
thereto is given by OSI to its stockholders:

         (a)  a copy of such notice, together with any proxy or information
              statement and related materials to be provided to holders of OSI
              Common Stock;

         (b)  a statement of the number of Holder Votes which the Holder is
              entitled to exercise;

         (c)  a statement that such Holder is entitled to instruct the Trustee
              as to the exercise of the Holder Votes with respect to such OSI
              Meeting or OSI Consent, as the case may be, or, pursuant to
              Section 4.7 hereof, to attend such OSI Meeting and to exercise
              personally the Holder Votes thereat;

         (d)  a statement as to the manner in which such instructions may be
              given to the Trustee, including an express indication that
              instructions may be given to the Trustee to give:

              (i)  a proxy to such Holder or such Holder's designee to exercise
                   personally the Holder Votes; or

              (ii)  a proxy to a designated agent or other representative of the
                    management of OSI to exercise such Holder Votes;

         (e)  a statement that if no voting instructions are received from the
              Holder, the Holder Votes to which such Holder is entitled will not
              be exercised;

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         (f)  a form of direction whereby the Holder may so direct and instruct
              the Trustee as contemplated herein; and

         (g)  a statement of (i) the time and date by which such instructions
              must be received by the Trustee in order to be binding upon it,
              which in the case of a OSI Meeting shall not be earlier than the
              close of business on the Business Day prior to such meeting, and
              (ii) the method for revoking or amending such instructions.

         The materials referred to above are to be provided by OSI to the
Trustee, but shall be subject to review and comment by the Trustee.

         For the purpose of determining Holder Votes to which a Holder is
entitled in respect of any such OSI Meeting or OSI Consent, the number of
Exchangeable Shares owned of record by the Holder shall be determined at the
close of business on the record date established by OSI or by applicable law for
purposes of determining stockholders entitled to vote at such OSI Meeting or to
give written consent in connection with such OSI Consent. OSI will notify the
Trustee in writing of any decision of the board of directors of OSI with respect
to the calling of any such OSI Meeting or the seeking of any such OSI Consent
and shall provide all necessary information and materials to the Trustee in each
case promptly and in any event in sufficient time to enable the Trustee to
perform its obligations contemplated by this Section 4.3.

4.4      COPIES OF STOCKHOLDER INFORMATION

         OSI will deliver to the Trustee copies of all proxy materials,
(including notices of OSI Meetings, but excluding proxies to vote shares of OSI
Common Stock), information statements, reports (including without limitation all
interim and annual financial statements) and other written communications that
are to be distributed from time to time to holders of OSI Common Stock in
sufficient quantities and in sufficient time so as to enable the Trustee to send
those materials to each Holder, to the extent possible, at the same time as such
materials are first sent to holders of OSI Common Stock. The Trustee will mail
or otherwise send to each Holder, at the expense of OSI, copies of all such
materials (and all materials specifically directed to the Holders or to the
Trustee for the benefit of the Holders by OSI) received by the Trustee from OSI,
to the extent possible, at the same time as such materials are first sent to
holders of OSI Common Stock. The Trustee will make copies of all such materials
available for inspection by any Holder at the Trustee's principal transfer
office in the cities of Calgary and Toronto.

4.5      OTHER MATERIALS

         Immediately after receipt by OSI or any stockholder of OSI of any
material sent or given generally to the holders of OSI Common Stock by or on
behalf of a third party, including without limitation dissident proxy and
information circulars (and related information and material) and tender and
exchange offer circulars (and related information and material), OSI shall use
its reasonable best efforts to obtain and deliver to the Trustee copies thereof
in sufficient quantities so as to enable the Trustee to forward such material
(unless the same has been provided directly to Holders by such third party) to
each Holder as soon as possible thereafter. As soon as practicable after receipt
thereof, the Trustee will mail or otherwise send to each Holder, at the expense
of OSI, copies of all such materials received by the Trustee from OSI. The
Trustee will

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also make copies of all such materials available for inspection by any Holder at
the Trustee's principal transfer office in the cities of Calgary and Toronto.

4.6      LIST OF PERSONS ENTITLED TO VOTE

         PTI Holdco shall, (i) prior to each annual, general or special OSI
Meeting or the seeking of any OSI Consent and (ii) forthwith upon each request
made at any time by the Trustee in writing, prepare or cause to be prepared a
list (a "List") of the names and addresses of the Holders arranged in
alphabetical order and showing the number of Exchangeable Shares held of record
by each such Holder, in each case at the close of business on the date specified
by the Trustee in such request or, in the case of a List prepared in connection
with a OSI Meeting or a OSI Consent, at the close of business on the record date
established by OSI or pursuant to applicable law for determining the holders of
OSI Common Stock entitled to receive notice of and/or to vote at such OSI
Meeting or to give consent in connection with such OSI Consent. Each such List
shall be delivered to the Trustee promptly after receipt by PTI Holdco of such
request or the record date for such meeting or seeking of consent, as the case
may be, and in any event within sufficient time as to enable the Trustee to
perform its obligations under this agreement. OSI agrees to give PTI Holdco
written notice (with a copy to the Trustee) of the calling of any OSI Meeting or
the seeking of any OSI Consent, together with the record dates therefor,
sufficiently prior to the date of the calling of such meeting or seeking of such
consent so as to enable PTI Holdco to perform its obligations under this Section
4.6.

4.7      ENTITLEMENT TO DIRECT VOTES

         Any Holder named in a List prepared in connection with any OSI Meeting
or any OSI Consent will be entitled (i) to instruct the Trustee in the manner
described in Section 4.3 hereof with respect to the exercise of the Holder Votes
to which such Holder is entitled or (ii) to attend such meeting and personally
to exercise thereat (or to exercise with respect to any written consent), as the
proxy of the Trustee, the Holder Votes to which such Holder is entitled.

4.8      VOTING BY TRUSTEE, AND ATTENDANCE OF TRUSTEE REPRESENTATIVE, AT MEETING

         (a)  In connection with each OSI Meeting and OSI Consent, the Trustee
              shall exercise, either in person or by proxy, in accordance with
              the instructions received from a Holder pursuant to Section 4.3
              hereof, the Holder Votes as to which such Holder is entitled to
              direct the vote (or any lesser number thereof as may be set forth
              in the instructions); provided, however, that such written
              instructions are received by the Trustee from the Holder prior to
              the time and date fixed by it for receipt of such instructions in
              the notice given by the Trustee to the Holder pursuant to Section
              4.3 hereof.

         (b)  The Trustee shall cause such representatives as are empowered by
              it to sign and deliver, on behalf of the Trustee, proxies for
              Voting Rights to attend each OSI Meeting. Upon submission by a
              Holder (or its designee) of identification satisfactory to the
              Trustee's representatives, and at the Holder's request, such
              representatives shall sign and deliver to such Holder (or its
              designee) a proxy to

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              exercise personally the Holder Votes as to which such Holder is
              otherwise entitled hereunder to direct the vote, if such Holder
              either:

              (i)   has not previously given the Trustee instructions pursuant
                    to Section 4.3 hereof in respect of such OSI Meeting, or

              (ii)  submits to the Trustee's representatives written revocation
                    of any such previous instructions.

         At such OSI Meeting, the Holder exercising such Holder Votes shall have
the same rights as the Trustee to speak at the meeting in respect of any matter,
question or proposition, to vote by way of ballot at the meeting in respect of
any matter, question or proposition and to vote at such meeting by way of a show
of hands in respect of any matter, question or proposition.

4.9      DISTRIBUTION OF WRITTEN MATERIALS

         Any written materials to be distributed by the Trustee to the Holders
pursuant to this agreement shall be delivered or sent by mail (or otherwise
communicated in the same manner as OSI utilizes in communications to holders of
OSI Common Stock subject to the Trustee's ability to provide this method of
communication and upon being advised in writing of such method) to each Holder
at its address as shown on the books of PTI Holdco. PTI Holdco shall provide or
cause to be provided to the Trustee for this purpose, on a timely basis and
without charge or other expense:

         (a)  current lists of the Holders; and

         (b)  on the request of the Trustee, mailing labels to enable the
              Trustee to carry out its duties under this agreement.

         The materials referred to above are to be provided by PTI Holdco to the
Trustee, but shall be subject to review and comment by the Trustee.

4.10     TERMINATION OF VOTING RIGHTS

         Except as otherwise provided herein or in the Exchangeable Share
Provisions, all of the rights of a Holder with respect to the Holder Votes
exercisable in respect of the Exchangeable Shares held by such Holder, including
the right to instruct the Trustee as to the voting of or to vote personally such
Holder Votes, shall be deemed to be surrendered by the Holder to OSI, and such
Holder Votes and the Voting Rights represented thereby shall cease immediately,
upon the delivery by such Holder to the Trustee of the certificates representing
such Exchangeable Shares in connection with the exercise by the Holder of the
Exchange Right or the occurrence of the automatic exchange of Exchangeable
Shares for shares of OSI Common Stock, as specified in Article 5 hereof (unless
in any case OSI or OSI ULC shall not have delivered the Exchangeable Share
Consideration deliverable in exchange therefor to the Trustee for delivery to
the Holders), or upon the redemption of Exchangeable Shares pursuant to Article
6 or Article 7 of the Exchangeable Share Provisions, or upon the effective date
of the liquidation, dissolution or winding-up of PTI Holdco or any other
distribution of the assets of PTI Holdco among its shareholders for the purpose
of winding up its affairs pursuant to Article 5 of the Exchangeable

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Share Provisions, or upon the purchase of Exchangeable Shares from the holder
thereof by OSI pursuant to the exercise by OSI of the Retraction Call Right, the
Redemption Call Right or the Liquidation Call Right.

                                   ARTICLE 5
                      EXCHANGE RIGHT AND AUTOMATIC EXCHANGE

5.1      GRANT AND OWNERSHIP OF THE EXCHANGE RIGHT AND AUTOMATIC EXCHANGE RIGHTS

         OSI hereby grants to the Trustee as trustee for and on behalf of, and
for the use and benefit of, the Holders:

         (a)  the right (the "Exchange Right"), upon the occurrence and during
              the continuance of an Insolvency Event, to require OSI to purchase
              or cause OSI ULC to purchase from each or any Holder all or any
              part of the Exchangeable Shares held by the Holders; and

         (b)  the Automatic Exchange Rights,

all in accordance with the provisions of this agreement and the Exchangeable
Share Provisions, as the case may be. OSI hereby acknowledges receipt from the
Trustee as trustee for and on behalf of the Holders of good and valuable
consideration (and the adequacy thereof) for the grant of the Exchange Right and
the Automatic Exchange Rights by OSI to the Trustee. During the term of the
Trust and subject to the terms and conditions of this agreement, the Trustee
shall possess and be vested with full legal ownership of the Exchange Right and
the Automatic Exchange Rights and shall be entitled to exercise and enforce for
the benefit of the Holders all of the rights and powers of an owner with respect
to the Exchange Right and the Automatic Exchange Rights, provided that the
Trustee shall:

         (c)  hold the Exchange Right and the Automatic Exchange Rights and the
              legal title thereto as trustee solely for the use and benefit of
              the Holders in accordance with the provisions of this agreement;
              and

         (d)  except as specifically authorized by this agreement, have no power
              or authority to exercise or otherwise deal in or with the Exchange
              Right or the Automatic Exchange Rights, and the Trustee shall not
              exercise any such rights for any purpose other than the purposes
              for which this Trust is created pursuant to this agreement.

5.2      LEGENDED SHARE CERTIFICATES

         PTI Holdco will cause each certificate representing Exchangeable Shares
to bear an appropriate legend notifying the Holders of:

         (a)  their right to instruct the Trustee with respect to the exercise
              of the Exchange Right in respect of the Exchangeable Shares held
              by a Holder; and

         (b)  the Automatic Exchange Rights.

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5.3      GENERAL EXERCISE OF THE EXCHANGE RIGHT

         The Exchange Right shall be and remain vested in and exercised by the
Trustee. Subject to Section 7.15 hereof, the Trustee shall exercise the Exchange
Right only on the basis of instructions received pursuant to this Article 5 from
Holders entitled to instruct the Trustee as to the exercise thereof. To the
extent that no instructions are received from a Holder with respect to the
Exchange Right, the Trustee shall not exercise or permit the exercise of the
Exchange Right.

5.4      PURCHASE PRICE

         The purchase price payable by OSI or OSI ULC for each Exchangeable
Share to be purchased by OSI or OSI ULC under the Exchange Right shall be an
amount equal to the Exchangeable Share Price on the last Business Day prior to
the day of closing of the purchase and sale of such Exchangeable Share under the
Exchange Right. In connection with each exercise of the Exchange Right, OSI will
provide to the Trustee an Officer's Certificate setting forth the calculation of
the applicable Exchangeable Share Price for each Exchangeable Share. The
applicable Exchangeable Share Price for each such Exchangeable Share so
purchased may be satisfied only by OSI's issuing and delivering or causing to be
delivered to the Trustee, on behalf of the relevant Holder, the applicable
Exchangeable Share Consideration representing the total applicable Exchangeable
Share Price.

5.5      EXERCISE INSTRUCTIONS FOR EXCHANGE RIGHT

         Subject to the terms and conditions herein set forth, a Holder shall be
entitled, upon the occurrence and during the continuance of an Insolvency Event,
to instruct the Trustee to exercise the Exchange Right with respect to all or
any part of the Exchangeable Shares registered in the name of such Holder on the
books of PTI Holdco. To cause the exercise of the Exchange Right by the Trustee,
the Holder shall deliver to the Trustee, in person or by certified or registered
mail, at its principal transfer offices in Calgary, Alberta or at such other
places in Canada as the Trustee may from time to time designate by written
notice to the Holders, the certificates representing the Exchangeable Shares
which such Holder desires OSI to purchase, duly endorsed in blank, and
accompanied by such other documents and instruments as may be required to effect
a transfer of Exchangeable Shares under applicable law and the by-laws of PTI
Holdco and such additional documents and instruments as the Trustee may
reasonably require, together with:

         (a)  a duly completed form of notice of exercise of the Exchange Right,
              contained on the reverse of or attached to the Exchangeable Share
              certificates, stating:

              (i)   that the Holder thereby instructs the Trustee to exercise
                    the Exchange Right so as to require OSI or OSI ULC to
                    purchase from the Holder the number of Exchangeable Shares
                    specified therein,

              (ii)  that such Holder has good title to and owns all such
                    Exchangeable Shares to be acquired by OSI or OSI ULC free
                    and clear of all liens, claims, encumbrances, security
                    interests and adverse claims or interests,

                                       12
<PAGE>   13

              (iii) the names in which the certificates representing OSI Common
                    Stock issuable in connection with the exercise of the
                    Exchange Right are to be issued, and

              (iv)  the names and addresses of the persons to whom the
                    Exchangeable Share Consideration should be delivered; and

         (b)  payment (or evidence satisfactory to the Trustee, PTI Holdco and
              OSI or OSI ULC of payment) of the taxes (if any) payable as
              contemplated by Section 5.8 of this agreement.

If only a part of the Exchangeable Shares represented by any certificate or
certificates delivered to the Trustee are to be purchased by OSI or OSI ULC
under the Exchange Right, a new certificate for the balance of such Exchangeable
Shares shall be issued to the Holder at the expense of PTI Holdco.

5.6      DELIVERY OF EXCHANGEABLE SHARE CONSIDERATION; EFFECT OF EXERCISE

         Promptly after receipt of the certificates representing the
Exchangeable Shares which the Holder desires OSI or OSI ULC to purchase under
the Exchange Right (together with such documents and instruments of transfer and
a duly completed form of notice of exercise of the Exchange Right), duly
endorsed for transfer to OSI, the Trustee shall notify OSI, OSI ULC and PTI
Holdco of its receipt of the same, which notice to OSI, OSI ULC and PTI Holdco
shall constitute exercise of the Exchange Right by the Trustee on behalf of the
Holder of such Exchangeable Shares, and OSI or OSI ULC shall immediately
thereafter deliver or cause to be delivered to the Trustee, for delivery to the
Holder of such Exchangeable Shares (or to such other persons, if any, properly
designated by such Holder), the Exchangeable Share Consideration deliverable in
connection with the exercise of the Exchange Right; provided, however, that no
such delivery shall be made unless and until the Holder requesting the same
shall have paid (or provided evidence satisfactory to the Trustee, PTI Holdco
and OSI or OSI ULC of the payment of) the taxes (if any) payable as contemplated
by Section 5.8 of this agreement. Immediately upon the giving of notice by the
Trustee to OSI, OSI ULC and PTI Holdco of the exercise of the Exchange Right, as
provided in this Section 5.6, (i) the closing of the transaction of purchase and
sale contemplated by the Exchange Right shall be deemed to have occurred, (ii)
OSI or OSI ULC shall be required to take all action necessary to permit it to
occur, including delivery to the Trustee of the relevant Exchangeable Share
Consideration, no later than the close of business on the third Business Day
following the receipt by the Trustee of notice, certificates and other documents
as aforesaid and (iii) the Holder of such Exchangeable Shares shall be deemed to
have transferred to OSI or OSI ULC all of its right, title and interest in and
to such Exchangeable Shares and the related interest in the Trust Estate, shall
cease to be a holder of such Exchangeable Shares and shall not be entitled to
exercise any of the rights of a holder in respect thereof, other than the right
to receive his proportionate part of the total purchase price therefor, unless
such Exchangeable Share Consideration is not delivered by OSI or OSI ULC to the
Trustee by the date specified above, in which case the rights of the Holder
shall remain unaffected until such Exchangeable Share Consideration is delivered
by OSI or OSI ULC and any cheque included therein is paid. Concurrently with
such Holder ceasing to be a holder of Exchangeable Shares, the Holder shall be
considered and deemed for all purposes to be the

                                       13
<PAGE>   14

holder of the shares of OSI Common Stock delivered to it pursuant to the
Exchange Right. Notwithstanding the foregoing, until the Exchangeable Share
Consideration is delivered to the Holder, the Holder shall be deemed to still be
a holder of the sold Exchangeable Shares for purposes of the Voting Rights with
respect thereto.

5.7      EXERCISE OF EXCHANGE RIGHT SUBSEQUENT TO RETRACTION

         In the event that a Holder has exercised its right under Article 6 of
the Exchangeable Share Provisions to require PTI Holdco to redeem any or all of
the Exchangeable Shares held by the Holder (the "Retracted Shares") and is
notified by PTI Holdco pursuant to Section 6.6 of the Exchangeable Share
Provisions that PTI Holdco will not be permitted as a result of liquidity or
solvency provisions of applicable law to redeem all such Retracted Shares,
subject to receipt by the Trustee of written notice to that effect from PTI
Holdco and provided that OSI or OSI ULC shall not have exercised the Retraction
Call Right with respect to the Retracted Shares and that the Holder has not
revoked the retraction request delivered by the Holder to PTI Holdco pursuant to
Section 6.1 of the Exchangeable Share Provisions, the retraction request will
constitute and will be deemed to constitute notice from the Holder to the
Trustee instructing the Trustee to exercise the Exchange Right with respect to
those Retracted Shares which PTI Holdco is unable to redeem. In any such event,
PTI Holdco hereby agrees with the Trustee and in favour of the Holder
immediately to notify the Trustee of such prohibition against PTI Holdco's
redeeming all of the Retracted Shares and immediately to forward or cause to be
forwarded to the Trustee all relevant materials delivered by the Holder to PTI
Holdco or to the transfer agent of the Exchangeable Shares (including without
limitation a copy of the retraction request delivered pursuant to Section 6.1 of
the Exchangeable Share Provisions) in connection with such proposed redemption
of the Retracted Shares, and the Trustee will thereupon exercise the Exchange
Right with respect to the Retracted Shares which PTI Holdco is not permitted to
redeem and will require OSI or OSI ULC to purchase such shares in accordance
with the provisions of this Article 5.

5.8      STAMP OR OTHER TRANSFER TAXES

         Upon any sale of Exchangeable Shares to OSI or OSI ULC pursuant to the
Exchange Right or the Automatic Exchange Rights, the share certificate or
certificates representing OSI Common Stock to be delivered in connection with
the payment of the total purchase price therefor shall be issued in the name of
the Holder of the Exchangeable Shares so sold or in such names as such Holder
may otherwise direct in writing without charge to the holder of the Exchangeable
Shares so sold, provided, however, that such Holder:

         (a)  shall pay (and none of OSI, OSI ULC, PTI Holdco or the Trustee
              shall be required to pay) any documentary, stamp, transfer or
              other similar taxes that may be payable in respect of any transfer
              involved in the issuance or delivery of such shares to a person
              other than such Holder; or

         (b)  shall have established to the satisfaction of the Trustee, OSI,
              OSI ULC and PTI Holdco that such taxes, if any, have been paid.

                                       14
<PAGE>   15

PTI Holdco and the Trustee (as directed in writing by PTI Holdco) shall be
entitled to deduct and withhold from any consideration otherwise payable under
this Agreement to any Holder such amounts as PTI Holdco or the Trustee is
required or permitted to deduct and withhold with respect to such payment under
the Income Tax Act (Canada), the United States Internal Revenue Code of 1986 or
any provision of provincial, state, local or foreign tax law, in each case as
amended or succeeded unless such Holder provides to PTI Holdco certificates or
such other assurances as are provided for under the Income Tax Act (Canada), the
United States Internal Revenue Code of 1986 or such other applicable taxation
provisions. To the extent that amounts are so withheld, such withheld amounts
shall be treated for all purposes as having been paid to the Holder in respect
of which such deduction and withholding was made, provided that such withheld
amounts are actually remitted to the appropriate taxing authority as and when
required. To the extent that the amount so required or permitted to be deducted
or withheld from any payment to a Holder exceeds the cash portion, if any, of
the consideration otherwise payable to the Holder, PTI Holdco and the Trustee
are hereby authorized to sell or otherwise dispose of such portion of the
consideration as is necessary to provide sufficient funds to PTI Holdco or the
Trustee, as the case may be, to enable it to comply with such deduction or
withholding requirement and PTI Holdco or the Trustee shall notify the Holder
and remit to such Holder any unapplied balance of the net proceeds of such sale.

5.9      NOTICE OF INSOLVENCY EVENT

         Immediately upon the occurrence of an Insolvency Event or any event
which with the giving of notice or the passage of time or both would be an
Insolvency Event, PTI Holdco and OSI shall give written notice thereof to the
Trustee. As soon as practicable after receiving notice from PTI Holdco or OSI of
the occurrence of an Insolvency Event, the Trustee will mail to each Holder, at
the expense of OSI, a notice of such Insolvency Event in the form provided by
OSI, which notice shall contain a brief statement of the right of the Holders
with respect to the Exchange Right.

5.10     QUALIFICATION OF OSI COMMON STOCK

         OSI covenants with the Trustee for the benefit of Holders that if any
shares of OSI Common Stock (or other shares or securities into which OSI Common
Stock may be reclassified or changed as contemplated by Section 2.7 of the
Support Agreement) to be issued and delivered pursuant to the Exchange Right or
the Automatic Exchange Rights require registration or qualification with or
approval of or the filing of any document including any prospectus or similar
document, the taking of any proceeding with or the obtaining of any order,
ruling or consent from any governmental or regulatory authority under any
Canadian or United States federal, provincial or state law or regulation or
pursuant to the rules and regulations of any regulatory authority, or the
fulfillment of any other legal requirement (collectively, the "Applicable Laws")
before such shares (or other shares or securities into which OSI Common Stock
may be reclassified or changed as contemplated by Section 2.7 of the Support
Agreement) may be issued and delivered by OSI to the initial holder thereof
(other than PTI Holdco) or in order that such shares may be freely tradeable
thereafter (other than any restrictions on transfer by reason of a holder being
a "control person" of OSI for purposes of Canadian provincial securities law or
an "affiliate" of OSI for purposes of United States federal or state securities
law and provided such trade is conducted through facilities of a stock exchange
outside Canada), OSI

                                       15
<PAGE>   16

will in good faith expeditiously take all such actions and do all such things as
are necessary and permitted by Applicable Laws to cause such shares of OSI
Common Stock (or other shares or securities into which OSI Common Stock may be
reclassified or changed as contemplated by Section 2.7 of the Support Agreement)
to be and remain duly registered, qualified or approved at all times in order
that such shares may be issued and delivered by OSI to the initial holder
thereof (other than PTI Holdco) and in order that such shares or securities may
be freely tradeable thereafter (other than any restrictions on transfer by
reason of a holder being a "control person" of OSI for purposes of Canadian
provincial securities law or an "affiliate" of OSI for purposes of United States
federal or state securities law and provided such trade is conducted through
facilities of a stock exchange outside Canada) including, without limitation,
the filing and maintenance of a registration statement under the Securities Act
of 1933. OSI will in good faith expeditiously take all such actions and do all
such things as are necessary to cause all shares of OSI Common Stock (or other
shares or securities into which OSI Common Stock may be reclassified or changed
as contemplated by Section 2.7 of the Support Agreement) to be delivered
pursuant to the Exchange Right or the Automatic Exchange Rights to be listed,
quoted or posted for trading on all stock exchanges and quotation systems on
which such shares are listed, quoted or posted for trading at such time
immediately upon their issuance.

5.11     RESERVATION OF SHARES OF OSI COMMON STOCK

         OSI hereby represents, warrants and covenants with the Trustee for the
benefit of the Holders that it has irrevocably reserved for issuance and will at
all times keep available, free from pre-emptive and other rights, out of its
authorized and unissued capital stock such number of shares of OSI Common Stock:

         (a)  as is equal to the sum of

              (i)   the number of Exchangeable Shares issued and outstanding
                    from time to time, and

              (ii)  the number of PTI Stock Options outstanding on the date
                    hereof; and

         (b)  as are now and may hereafter be required to enable and permit PTI
              Holdco to meet its obligations hereunder, under the Certificate of
              Incorporation of PTI Holdco, under the Support Agreement, under
              the Exchangeable Share Provisions and under any other security or
              commitment pursuant to the Arrangement with respect to which OSI
              may now or hereafter be required to issue shares of OSI Common
              Stock.

5.12     AUTOMATIC EXCHANGE ON LIQUIDATION OF OSI

         (a)  OSI will give the Trustee written notice of each of the following
              events at the time set forth below:

              (i)   in the event of any determination by the board of directors
                    of OSI to institute voluntary liquidation, dissolution or
                    winding-up proceedings with respect to OSI or to effect any
                    other distribution of assets of OSI among its stockholders
                    for the purpose of winding-up its affairs, at least 60 days

                                       16
<PAGE>   17

                    prior to the proposed effective date of such liquidation,
                    dissolution, winding-up or other distribution; and

         (ii) immediately, upon the earlier of

              (A) receipt by OSI of notice of, and

              (B) OSI otherwise becoming aware of

         any threatened or instituted claim, suit, petition or other proceedings
         with respect to the involuntary liquidation, dissolution or winding-up
         of OSI or to effect any other distribution of assets of OSI among its
         stockholders for the purpose of winding up its affairs.

         (b)  Immediately following receipt by the Trustee from OSI of notice of
              any event (a "Liquidation Event") contemplated by Section 5.12(a)
              above, the Trustee will give notice thereof to the Holders. Such
              notice will be provided by OSI to the Trustee and shall include a
              brief description of the automatic exchange of Exchangeable Shares
              for shares of OSI Common Stock provided for in Section 5.12(c)
              below.

         (c)  In order that the Holders will be able to participate on a pro
              rata basis with the holders of OSI Common Stock in the
              distribution of assets of OSI in connection with a Liquidation
              Event, immediately prior to the effective time (the "Liquidation
              Event Effective Time") of a Liquidation Event, all of the then
              outstanding Exchangeable Shares shall be automatically exchanged
              for shares of OSI Common Stock. To effect such automatic exchange,
              OSI shall be deemed to have purchased each Exchangeable Share
              outstanding immediately prior to the Liquidation Event Effective
              Time and held by Holders, and each Holder shall be deemed to have
              sold the Exchangeable Shares held by it at such time, for a
              purchase price per share equal to the Exchangeable Share Price
              applicable at such time. In connection with such automatic
              exchange, OSI will provide to the Trustee an Officer's Certificate
              setting forth the calculation of the Exchangeable Share Price for
              each Exchangeable Share.

         (d)  The closing of the transaction of purchase and sale contemplated
              by Section 5.12(c) above shall be deemed to have occurred
              immediately prior to the Liquidation Event Effective Time, and
              each Holder of Exchangeable Shares shall be deemed to have
              transferred to OSI all of the Holder's right, title and interest
              in and to such Exchangeable Shares and the related interest in the
              Trust Estate and shall cease to be a holder of such Exchangeable
              Shares, and OSI shall deliver to the Holder the Exchangeable Share
              Consideration deliverable upon the automatic exchange of
              Exchangeable Shares. Concurrently with such Holder's ceasing to be
              a holder of Exchangeable Shares, the Holder shall be considered
              and deemed for all purposes to be the holder of the shares of OSI
              Common Stock issued to it pursuant to the automatic exchange of
              Exchangeable Shares for OSI Common Stock, and the certificates
              held by the Holder previously representing the

                                       17
<PAGE>   18

              Exchangeable Shares exchanged by the Holder with OSI pursuant to
              such automatic exchange shall thereafter be deemed to represent
              the shares of OSI Common Stock issued to the Holder by OSI
              pursuant to such automatic exchange. Upon the request of a Holder
              and the surrender by the Holder of Exchangeable Share certificates
              deemed to represent shares of OSI Common Stock, duly endorsed in
              blank and accompanied by such instruments of transfer as OSI may
              reasonably require, OSI shall deliver or cause to be delivered to
              the Holder certificates representing the shares of OSI Common
              Stock of which the Holder is the holder. Notwithstanding the
              foregoing, until each Holder is actually entered on the register
              of holders of OSI Common Stock, such Holder shall be deemed to
              still be a holder of the transferred Exchangeable Shares for
              purposes of all Voting Rights with respect thereto.

                                   ARTICLE 6
              RESTRICTIONS ON ISSUANCE OF OSI SPECIAL VOTING STOCK

         During the term of this agreement, OSI will not issue any shares of OSI
Special Voting Stock in addition to the Voting Share.

                                   ARTICLE 7
                             CONCERNING THE TRUSTEE

7.1      POWERS AND DUTIES OF THE TRUSTEE

         The rights, powers and authorities of the Trustee under this agreement,
in its capacity as trustee of the Trust, shall include:

         (a)  receipt and deposit of the Voting Share from OSI as trustee for
              and on behalf of the Holders in accordance with the provisions of
              this agreement;

         (b)  granting proxies and distributing materials to Holders as provided
              in this agreement;

         (c)  voting the Holder Votes in accordance with the provisions of this
              agreement;

         (d)  receiving the grant of the Exchange Right and the Automatic
              Exchange Rights from OSI as trustee for and on behalf of the
              Holders in accordance with the provisions of this agreement;

         (e)  exercising the Exchange Right and enforcing the benefit of the
              Automatic Exchange Rights, in each case in accordance with the
              provisions of this agreement, and in connection therewith
              receiving from Holders Exchangeable Shares and other requisite
              documents and distributing to such Holders the shares of OSI
              Common Stock and cheques and property, if any, to which such
              Holders are entitled upon the exercise of the Exchange Right or
              pursuant to the Automatic Exchange Rights, as the case may be;

         (f)  holding title to the Trust Estate;

                                       18
<PAGE>   19

         (g)  investing any moneys forming, from time to time, a part of the
              Trust Estate as provided in this agreement;

         (h)  taking action at the direction of a Holder or Holders to enforce
              the obligations of OSI under this agreement; and

         (i)  taking such other actions and doing such other things as are
              specifically provided in this agreement.

         In the exercise of such rights, powers and authorities, the Trustee
shall have (and is granted) such incidental and additional rights, powers and
authority not in conflict with any of the provisions of this agreement as the
Trustee, acting in good faith and in the reasonable exercise of its discretion,
may deem necessary, appropriate or desirable to effect the purpose of the Trust.
Any exercise of such discretionary rights, powers and authorities by the Trustee
shall be final, conclusive and binding upon all persons. For greater certainty,
the Trustee shall have only those duties as are set out specifically in this
agreement. The Trustee in exercising its rights, powers, duties and authorities
hereunder shall act honestly and in good faith with a view to the best interests
of the Holders and shall exercise the care, diligence and skill that a
reasonably prudent trustee would exercise in comparable circumstances. The
Trustee shall not be bound to give any notice or do or take any act, action or
proceeding by virtue of the powers conferred on it hereby unless and until it
shall be specifically required to do so under the terms hereof nor shall the
Trustee be required to take any notice of, or to do or to take any act, action
or proceeding as a result of any default or breach of any provision hereunder,
unless and until notified in writing of such default or breach, which notices
shall distinctly specify the default or breach desired to be brought to the
attention of the Trustee and in the absence of such notice the Trustee may for
all purposes of this agreement conclusively assume that no default or breach has
been made in the observance or performance of any of the representations,
warranties, covenants, agreements or conditions contained herein.

7.2      NO CONFLICT OF INTEREST

         The Trustee represents to PTI Holdco and OSI that at the date of
execution and delivery of this agreement there exists no material conflict of
interest in the role of the Trustee as a fiduciary hereunder and the role of the
Trustee in any other capacity. The Trustee shall, within 90 days after it
becomes aware that such a material conflict of interest exists, either eliminate
such material conflict of interest or resign in the manner and with the effect
specified in Article 10 hereof. If, notwithstanding the foregoing provisions of
this Section 7.2, the Trustee has such a material conflict of interest, the
validity and enforceability of this agreement shall not be affected in any
manner whatsoever by reason only of the existence of such material conflict of
interest. If the Trustee contravenes the foregoing provisions of this Section
7.2, any interested party may apply to the superior court of the province in
which PTI Holdco has its registered office for an order that the Trustee be
replaced as trustee hereunder.

                                       19
<PAGE>   20

7.3      DEALINGS WITH TRANSFER AGENTS, REGISTRARS, ETC.

         PTI Holdco and OSI irrevocably authorize the Trustee, from time to
time, to:

         (a)  consult, communicate and otherwise deal with the respective
              registrars and transfer agents, and with any such subsequent
              registrar or transfer agent, of the Exchangeable Shares and OSI
              Common Stock; and

         (b)  requisition, from time to time,

              (i)   from any such registrar or transfer agent any information
                    readily available from the records maintained by it which
                    the Trustee may reasonably require for the discharge of its
                    duties and responsibilities under this agreement, and

              (ii)  from the transfer agent of OSI Common Stock, and any
                    subsequent transfer agent of such shares, to complete the
                    exercise from time to time of the Exchange Right and the
                    Automatic Exchange Rights in the manner specified in Article
                    5 hereof, the share certificates issuable upon such
                    exercise.

         PTI Holdco and OSI irrevocably authorize their respective registrars
and transfer agents to comply with all such requests. OSI covenants that it will
supply its transfer agent with duly executed share certificates for the purpose
of completing the exercise from time to time of the Exchange Right and the
Automatic Exchange Rights, in each case pursuant to Article 5 hereof.

7.4      BOOKS AND RECORDS

         The Trustee shall keep available for inspection by OSI and PTI Holdco,
at the Trustee's principal transfer office in Calgary, Alberta, correct and
complete books and records of account relating to the Trustee's actions under
this agreement, including without limitation all information relating to
mailings and instructions to and from Holders and all transactions pursuant to
the Voting Rights, the Exchange Right and the Automatic Exchange Rights for the
term of this agreement. On or before March 31, 2001, and on or before March 31
in every year thereafter, so long as the Voting Share is on deposit with the
Trustee, the Trustee shall transmit to OSI and PTI Holdco a brief report, dated
as of the preceding December 31, with respect to:

         (a)  the property and funds comprising the Trust Estate as of that
              date;

         (b)  the number of exercises of the Exchange Right, if any, and the
              aggregate number of Exchangeable Shares received by the Trustee on
              behalf of Holders in consideration of the issue and delivery by
              OSI of shares of OSI Common Stock in connection with the Exchange
              Right, during the calendar year ended on such date; and

         (c)  all other actions taken by the Trustee in the performance of its
              duties under this agreement which it had not previously reported.

                                       20
<PAGE>   21

7.5      INCOME TAX RETURNS AND REPORTS

         The Trustee shall, to the extent necessary, prepare and file on behalf
of the Trust appropriate United States and Canadian income tax returns and any
other returns or reports as may be required by applicable law or pursuant to the
rules and regulations of any securities exchange or other trading system through
which the Exchangeable Shares are traded and, in connection therewith, may
obtain the advice and assistance of such experts as the Trustee may consider
necessary or advisable. If requested by the Trustee, OSI shall retain such
experts for purposes of providing such advice and assistance.

7.6      INDEMNIFICATION PRIOR TO CERTAIN ACTIONS BY TRUSTEE

         The Trustee shall exercise any or all of the rights, duties, powers or
authorities vested in it by this agreement at the request, order or direction of
any Holder upon such Holder's furnishing to the Trustee reasonable funding,
security and indemnity against the costs, expenses and liabilities which may be
incurred by the Trustee therein or thereby; provided that no Holder shall be
obligated to furnish to the Trustee any such funding, security or indemnity in
connection with the exercise by the Trustee of any of its rights, duties, powers
and authorities with respect to the Voting Share pursuant to Article 4 hereof,
subject to Section 7.15 hereof, and with respect to the Exchange Right pursuant
to Article 5 hereof, subject to Section 7.15 hereof, and with respect to the
Automatic Exchange Rights pursuant to Article 5 hereof. None of the provisions
contained in this agreement shall require the Trustee to expend or risk its own
funds or otherwise incur financial liability in the exercise of any of its
rights, powers, duties or authorities unless funded, given funds, security and
indemnified as aforesaid.

7.7      ACTIONS BY HOLDERS

         No Holder shall have the right to institute any action, suit or
proceeding or to exercise any other remedy authorized by this agreement for the
purpose of enforcing any of its rights or for the execution of any trust or
power hereunder unless the Holder has requested the Trustee to take or institute
such action, suit or proceeding and furnished the Trustee with the funding,
security and indemnity referred to in Section 7.6 hereof and the Trustee shall
have failed to act within a reasonable time thereafter. In such case, but not
otherwise, the Holder shall be entitled to take proceedings in any court of
competent jurisdiction such as the Trustee might have taken; it being understood
and intended that no one or more Holders shall have any right in any manner
whatsoever to affect, disturb or prejudice the rights hereby created by any such
action, or to enforce any right hereunder or under the Voting Rights, the
Exchange Right or the Automatic Exchange Rights, except subject to the
conditions and in the manner herein provided, and that all powers and trusts
hereunder shall be exercised and all proceedings at law shall be instituted, had
and maintained by the Trustee, except only as herein provided, and in any event
for the equal benefit of all Holders.

7.8      RELIANCE UPON DECLARATIONS

         The Trustee shall not be considered to be in contravention of any of
its rights, powers, duties and authorities hereunder if, when required, it acts
and relies in good faith upon lists, mailing labels, notices, statutory
declarations, certificates, opinions, reports or other papers or

                                       21
<PAGE>   22

documents furnished pursuant to the provisions hereof or required by the Trustee
to be furnished to it in the exercise of its rights, powers, duties and
authorities hereunder, and such lists, mailing labels, notices, statutory
declarations, certificates, opinions, reports or other papers or documents
comply with the provisions of Section 7.9 hereof, if applicable, and with any
other applicable provisions of this agreement.

7.9      EVIDENCE AND AUTHORITY TO TRUSTEE

         PTI Holdco and/or OSI shall furnish to the Trustee evidence of
compliance with the conditions provided for in this agreement relating to any
action or step required or permitted to be taken by PTI Holdco and/or OSI or the
Trustee under this agreement or as a result of any obligation imposed under this
agreement, including, without limitation, in respect of the Voting Rights or the
Exchange Right or the Automatic Exchange Rights and the taking of any other
action to be taken by the Trustee at the request of or on the application of PTI
Holdco and/or OSI forthwith if and when:

         (a)  such evidence is required by any other section of this agreement
              to be furnished to the Trustee in accordance with the terms of
              this Section 7.9; or

         (b)  the Trustee, in the exercise of its rights, powers, duties and
              authorities under this agreement, gives PTI Holdco and/or OSI
              written notice requiring it to furnish such evidence in relation
              to any particular action or obligation specified in such notice.

         Such evidence shall consist of an Officer's Certificate of PTI Holdco
and/or OSI or a statutory declaration or a certificate made by persons entitled
to sign an Officer's Certificate stating that any such condition has been
complied with in accordance with the terms of this agreement.

         Whenever such evidence relates to a matter other than the Voting Rights
or the Exchange Right or the Automatic Exchange Rights, and except as otherwise
specifically provided herein, such evidence may consist of a report or opinion
of any solicitor, auditor, accountant, appraiser, valuer, engineer or other
expert or any other person whose qualifications give authority to a statement
made by him, provided that, if such report or opinion is furnished by a
director, officer or employee of PTI Holdco and/or OSI, it shall be in the form
of an Officer's Certificate or a statutory declaration.

         Each statutory declaration, certificate, opinion or report furnished to
the Trustee as evidence of compliance with a condition provided for in this
agreement shall include a statement by the person giving the evidence:

              (i)   declaring that such person has read and understands the
                    provisions of this agreement relating to the condition in
                    question;

              (ii)  describing the nature and scope of the examination or
                    investigation upon which such person based the statutory
                    declaration, certificate, statement or opinion; and

                                       22
<PAGE>   23

              (iii) declaring that such person has made such examination or
                    investigation as such person believes is necessary to enable
                    such person to make the statements or give the opinions
                    contained or expressed therein.

7.10     EXPERTS, ADVISERS AND AGENTS

         The Trustee may:

         (a)  in relation to these presents act and rely on the opinion or
              advice of or information obtained from or prepared by any
              solicitor, auditor, accountant, appraiser, valuer, engineer or
              other expert, whether retained by the Trustee or by PTI Holdco
              and/or OSI or otherwise, and may employ such assistants as may be
              necessary to the proper determination and discharge of its powers
              and duties and determination of its rights hereunder and may pay
              proper and reasonable compensation for all such legal and other
              advice or assistance as aforesaid; and

         (b)  employ such agents and other assistants as it may reasonably
              require for the proper determination and discharge of its powers
              and duties hereunder, and may pay reasonable remuneration for all
              services performed for it (and shall be entitled to receive
              reasonable remuneration for all services performed by it) in the
              discharge of the trusts hereof and compensation for all
              disbursements, costs and expenses made or incurred by it in the
              determination and discharge of its duties hereunder and in the
              management of the Trust.

7.11     INVESTMENT OF MONEYS HELD BY TRUSTEE

         Unless otherwise provided in this agreement, any moneys held by or on
behalf of the Trustee which under the terms of this agreement may or ought to be
invested or which may be on deposit with the Trustee or which may be in the
hands of the Trustee, may be invested and reinvested in the name or under the
control of the Trustee in securities in which, under the laws of the Province of
Alberta, trustees are authorized to invest trust moneys; provided that such
securities are stated to mature within two years after their purchase by the
Trustee, and the Trustee shall so invest such moneys on the written direction of
PTI Holdco. Pending the investment of any moneys as hereinbefore provided, such
moneys may be deposited in the name of the Trustee in any chartered bank in
Canada or, with the consent of PTI Holdco, in the deposit department of the
Trustee or any other loan or trust company authorized to accept deposits under
the laws of Canada or any province thereof at the rate of interest then current
on similar deposits.

7.12     TRUSTEE NOT REQUIRED TO GIVE SECURITY

         The Trustee shall not be required to give any bond or security in
respect of the execution of the trusts, rights, duties, powers and authorities
of this agreement or otherwise in respect of the premises.

7.13     TRUSTEE NOT BOUND TO ACT ON REQUEST

         Except as in this agreement otherwise specifically provided, the
Trustee shall not be bound to act in accordance with any direction or request of
PTI Holdco and/or OSI or of the

                                       23
<PAGE>   24

directors thereof until a duly authenticated copy of the instrument or
resolution containing such direction or request shall have been delivered to the
Trustee, and the Trustee shall be empowered to act and rely upon any such copy
purporting to be authenticated and believed by the Trustee to be genuine.

7.14     AUTHORITY TO CARRY ON BUSINESS

         The Trustee represents to PTI Holdco and OSI that at the date of
execution and delivery by it of this agreement it is authorized to carry on the
business of a trust company in the Province of Alberta but if, notwithstanding
the provisions of this Section 7.14, it ceases to be so authorized to carry on
business, the validity and enforceability of this agreement and the Voting
Rights, the Exchange Right and the Automatic Exchange Rights shall not be
affected in any manner whatsoever by reason only of such event; provided,
however, the Trustee shall, within 90 days after ceasing to be authorized to
carry on the business of a trust company in the Province of Alberta, either
become so authorized or resign in the manner and with the effect specified in
Article 10 hereof.

7.15     CONFLICTING CLAIMS

         If conflicting claims or demands are made or asserted with respect to
any interest of any Holder in any Exchangeable Shares, including any
disagreement between the heirs, representatives, successors or assigns
succeeding to all or any part of the interest of any Holder in any Exchangeable
Shares resulting in conflicting claims or demands being made in connection with
such interest, then the Trustee shall be entitled, at its sole discretion, to
refuse to recognize or to comply with any such claim or demand. In so refusing,
the Trustee may elect not to exercise any Voting Rights, Exchange Right or
Automatic Exchange Rights subject to such conflicting claims or demands and, in
so doing, the Trustee shall not be or become liable to any person on account of
such election or its failure or refusal to comply with any such conflicting
claims or demands. The Trustee shall be entitled to continue to refrain from
acting and to refuse to act until:

         (a)  the rights of all adverse claimants with respect to the Voting
              Rights, Exchange Right or Automatic Exchange Rights subject to
              such conflicting claims or demands have been adjudicated by a
              final judgment of a court of competent jurisdiction; or

         (b)  all differences with respect to the Voting Rights, Exchange Right
              or Automatic Exchange Rights subject to such conflicting claims or
              demands have been conclusively settled by a valid written
              agreement binding on all such adverse claimants, and the Trustee
              shall have been furnished with an executed copy of such agreement.

         If the Trustee elects to recognize any claim or comply with any demand
made by any such adverse claimant, it may in its discretion require such
claimant to furnish such surety bond or other security satisfactory to the
Trustee as it shall deem appropriate fully to indemnify it as between all
conflicting claims or demands.

                                       24
<PAGE>   25

7.16     ACCEPTANCE OF TRUST

         The Trustee hereby accepts the Trust created and provided for by and in
this agreement and agrees to perform the same upon the terms and conditions
herein set forth and to hold all rights, privileges and benefits conferred
hereby and by law in trust for the various persons who shall from time to time
be Holders, subject to all the terms and conditions herein set forth.

                                   ARTICLE 8
                                  COMPENSATION

OSI and PTI Holdco jointly and severally agree to pay to the Trustee reasonable
compensation for all of the services rendered by it under this agreement and
will reimburse the Trustee for all reasonable expenses (including but not
limited to taxes, compensation paid to experts, agents and advisors, and travel
expenses) and disbursements, including the cost and expense of any suit or
litigation of any character and any proceedings before any governmental agency,
reasonably incurred by the Trustee in connection with its rights and duties
under this agreement; provided that OSI and PTI Holdco shall have no obligation
to reimburse the Trustee for any expenses or disbursements paid, incurred or
suffered by the Trustee in any suit or litigation in which the Trustee is
determined to have acted in bad faith or with negligence or willful misconduct.

                                   ARTICLE 9
                   INDEMNIFICATION AND LIMITATION OF LIABILITY

9.1      INDEMNIFICATION OF THE TRUSTEE

         OSI and PTI Holdco jointly and severally agree to indemnify and hold
harmless the Trustee and each of its directors, officers, employees and agents
appointed and acting in accordance with this agreement (collectively, the
"Indemnified Parties") against all claims, losses, damages, costs, penalties,
fines and reasonable expenses (including reasonable expenses of the Trustee's
legal counsel) which, without fraud, negligence, willful misconduct or bad faith
on the part of such Indemnified Party, may be paid, incurred or suffered by the
Indemnified Party by reason of or as a result of the Trustee's acceptance or
administration of the Trust, its compliance with its duties set forth in this
agreement, or any written or oral instructions delivered to the Trustee by OSI
or PTI Holdco pursuant hereto. In no case shall OSI or PTI Holdco be liable
under this indemnity for any claim against any of the Indemnified Parties unless
OSI and PTI Holdco shall be notified by the Trustee of the written assertion of
a claim or of any action commenced against the Indemnified Parties, promptly
after any of the Indemnified Parties shall have received any such written
assertion of a claim or shall have been served with a summons or other first
legal process giving information as to the nature and basis of the claim.
Subject to (ii) below, OSI and PTI Holdco shall be entitled to participate at
their own expense in the defense and, if OSI or

                                       25
<PAGE>   26

PTI Holdco so elect at any time after receipt of such notice, either of them may
assume the defense of any suit brought to enforce any such claim. The Trustee
shall have the right to employ separate counsel in any such suit and participate
in the defense thereof, but the fees and expenses of such counsel shall be at
the expense of the Trustee unless: (i) the employment of such counsel has been
authorized by OSI or PTI Holdco, such authorization not to be unreasonably
withheld; or (ii) the named parties to any such suit include both the Trustee
and OSI or PTI Holdco and the Trustee shall have been advised by counsel
acceptable to OSI or PTI Holdco that there may be one or more legal defenses
available to the Trustee that are different from or in addition to those
available to OSI or PTI Holdco and that an actual or potential conflict of
interest exists (in which case OSI and PTI Holdco shall not have the right to
assume the defense of such suit on behalf of the Trustee, but shall be liable to
pay the reasonable fees and expenses of counsel for the Trustee). This indemnity
shall survive the resignation or removal of the Trustee and the termination of
the trust.

9.2      LIMITATION OF LIABILITY

         The Trustee shall not be held liable for any loss which may occur by
reason of depreciation of the value of any part of the Trust Estate or any loss
incurred on any investment of funds pursuant to this agreement, except to the
extent that such loss is attributable to the fraud, negligence, willful
misconduct or bad faith on the part of the Trustee.

                                   ARTICLE 10
                                CHANGE OF TRUSTEE

10.1     RESIGNATION

         The Trustee, or any trustee hereafter appointed, may at any time resign
by giving written notice of such resignation to OSI and PTI Holdco specifying
the date on which it desires to resign, provided that such notice shall never be
given less than 60 days before such desired resignation date unless OSI and PTI
Holdco otherwise agree and provided further that such resignation shall not take
effect until the date of the appointment of a successor trustee and the
acceptance of such appointment by the successor trustee. Upon receiving such
notice of resignation, OSI and PTI Holdco shall promptly appoint a successor
trustee by written instrument, in duplicate, one copy of which shall be
delivered to the resigning trustee and one copy to the successor trustee.
Failing acceptance by a successor trustee, a successor trustee may be appointed
by an order of the superior court of the province in which PTI Holdco has its
registered office upon application of one or more of the parties hereto.

10.2     REMOVAL

         The Trustee, or any trustee hereafter appointed, may be removed with or
without cause, at any time on 60 days prior notice by written instrument
executed by OSI and PTI Holdco, in duplicate, one copy of which shall be
delivered to the trustee so removed and one copy to the successor trustee;
provided that, in connection with such removal, provision is made for a
replacement trustee similar to that contemplated in Section 10.1.

10.3     SUCCESSOR TRUSTEE

         Any successor trustee appointed as provided under this agreement shall
execute, acknowledge and deliver to OSI and PTI Holdco and to its predecessor
trustee an instrument accepting such appointment. Thereupon the resignation or
removal of the predecessor trustee shall become effective and such successor
trustee, without any further act, deed or conveyance, shall become vested with
all the rights, powers, duties and obligations of its predecessor under this
agreement, with like effect as if originally named as trustee in this agreement.
However, on the written request of OSI and PTI Holdco or of the successor
trustee, the trustee ceasing to act

                                       26
<PAGE>   27

shall, upon payment of any amounts then due it pursuant to the provisions of
this agreement, execute and deliver an instrument transferring to such successor
trustee all the rights and powers of the trustee so ceasing to act. Upon the
request of any such successor trustee, OSI, PTI Holdco and such predecessor
trustee shall execute any and all instruments in writing for more fully and
certainly vesting in and confirming to such successor trustee all such rights
and powers.

10.4     NOTICE OF SUCCESSOR TRUSTEE

         Upon acceptance of appointment by a successor trustee as provided
herein, OSI and PTI Holdco shall cause to be mailed notice of the succession of
such trustee hereunder to each Holder specified in a List. If OSI or PTI Holdco
shall fail to cause such notice to be mailed within 10 days after acceptance of
appointment by the successor trustee, the successor trustee shall cause such
notice to be mailed at the expense of OSI and PTI Holdco.

                                   ARTICLE 11
                                   SUCCESSORS

11.1     CERTAIN REQUIREMENTS IN RESPECT OF COMBINATION, ETC.

         Neither OSI nor PTI Holdco shall enter into any transaction (whether by
way of reconstruction, reorganization, consolidation, merger, transfer, sale,
lease or otherwise) whereby all or substantially all of its undertaking,
property and assets would become the property of any other Person or, in the
case of a merger, of the continuing corporation resulting therefrom, but may do
so if:

         (a)  (i)   such other Person or continuing corporation (the
                    "Successor"), by operation of law, becomes, without further
                    action, bound by the terms and provisions of this agreement
                    or, if not so bound, executes, prior to or contemporaneously
                    with the consummation of such transaction an agreement
                    supplemental hereto and such other instruments (if any) as
                    are satisfactory to the Trustee and in the opinion of legal
                    counsel to the Trustee are necessary or advisable to
                    evidence the assumption by the Successor of liability for
                    all moneys payable and property deliverable hereunder, the
                    covenant of such Successor to pay and deliver or cause to be
                    delivered the same and its agreement to observe and perform
                    all the covenants and obligations of OSI or PTI Holdco, as
                    the case may be, under this agreement; and

              (i)   such transaction shall, to the satisfaction of the Trustee,
                    be upon such terms which substantially preserve and do not
                    impair in any material respect any of the rights, duties,
                    powers and authorities of the Trustee or of the Holders
                    hereunder; or

         (b)  all Exchangeable Shares are redeemed or repurchased pursuant to
              Article 7 of the Exchangeable Share Provisions or under the
              Redemption Call Rights prior to or concurrently with the
              consummation of such transactions.

                                       27
<PAGE>   28

11.2     VESTING OF POWERS IN SUCCESSOR

         Whenever the conditions of Section 11. 1 hereof have been duly observed
and performed, the Trustee, if required by Section 11.1 hereof, the Successor
and OSI or PTI Holdco, as the case may be, shall execute and deliver the
supplemental agreement provided for in Article 12 hereof, and thereupon the
Successor shall possess and from time to time may exercise each and every right
and power of OSI or PTI Holdco, as the case may be, under this agreement in the
name of OSI or PTI Holdco, as the case may be, or otherwise and any act or
proceeding by any provision of this agreement required to be done or performed
by the board of directors or any officers of OSI or PTI Holdco may be done and
performed with like force and effect by the directors or officers of such
Successor.

11.3     WHOLLY-OWNED SUBSIDIARIES

         Nothing herein shall be construed as preventing: (a) the amalgamation
or merger of any wholly-owned subsidiary of OSI with or into OSI; or (b) the
winding-up, liquidation or dissolution of any wholly-owned subsidiary of OSI
provided that all of the assets of such subsidiary are transferred to OSI or
another wholly-owned subsidiary of OSI, and any such transactions are hereby
expressly permitted.

                                   ARTICLE 12
                     AMENDMENTS AND SUPPLEMENTAL AGREEMENTS

12.1     AMENDMENTS, MODIFICATIONS, ETC.

         Subject to Sections 12.2 and 12.4, this agreement may not be amended,
modified or waived except by an agreement in writing executed by PTI Holdco, OSI
and the Trustee and approved by the Holders in accordance with Section 9.2 of
the Exchangeable Share Provisions. No amendment to or modification or waiver of
any of the provisions of this agreement otherwise permitted hereunder shall be
effective unless made in writing and signed by all of the parties hereto.

12.2     MINISTERIAL AMENDMENTS

         Notwithstanding the provisions of Section 12.1 hereof, the parties to
this agreement may in writing, at any time and from time to time, without the
approval of the Holders, amend or modify this agreement for the purposes of:

         (a)  adding to the covenants of any or all of the parties hereto for
              the protection of the Holders hereunder subject to the receipt by
              the Trustee of an opinion of its counsel that the addition of the
              proposed covenant is not prejudicial to the interests of the
              Holders as a whole or the Trustee;

         (b)  making such amendments or modifications not inconsistent with this
              agreement as may be necessary or desirable with respect to matters
              or questions which, in the opinion of the board of directors of
              each of OSI and PTI Holdco and in the opinion of the Trustee and
              its counsel, having in mind the best interests of the Holders as a
              whole, it may be expedient to make, provided that such boards of

                                       28
<PAGE>   29

              directors and the Trustee and its counsel shall be of the opinion
              that such amendments and modifications will not be prejudicial to
              the interests of the Holders as a whole;

         (c)  making such changes or corrections which, on the advice of counsel
              to PTI Holdco, OSI and the Trustee, are required for the purpose
              of curing or correcting any ambiguity or defect or inconsistent
              provision or clerical omission or mistake or manifest error;
              provided that the Trustee and its counsel and the board of
              directors of each of PTI Holdco and OSI shall be of the opinion
              that such changes or corrections will not be prejudicial to the
              interests of the Holders as a whole; or

         (d)  making such changes as may be necessary or appropriate to
              implement or give effect to any assignment or assumption made
              pursuant to Section 14.9 hereof.

12.3     MEETING TO CONSIDER AMENDMENTS

         PTI Holdco, at the request of OSI, shall call a meeting or meetings of
the Holders for the purpose of considering any proposed amendment or
modification requiring approval pursuant hereto. Any such meeting or meetings
shall be called and held in accordance with the by-laws of PTI Holdco, the
Exchangeable Share Provisions and all applicable laws.

12.4     CHANGES IN CAPITAL OF OSI AND PTI HOLDCO

         At all times after the occurrence of any event effected pursuant to
Section 2.7 or Section 2.8 of the Support Agreement, as a result of which either
OSI Common Stock or the Exchangeable Shares or both are in any way changed, this
agreement shall forthwith be amended and modified as necessary in order that it
shall apply with full force and effect, mutatis mutandis, to all new securities
into which OSI Common Stock or the Exchangeable Shares or both are so changed,
and the parties hereto shall execute and deliver a supplemental agreement giving
effect to and evidencing such necessary amendments and modifications.

12.5     EXECUTION OF SUPPLEMENTAL AGREEMENTS

         From time to time, PTI Holdco (when authorized by a resolution of its
Board of Directors), OSI (when authorized by a resolution of its board of
directors) and the Trustee may, subject to the provisions of these presents, and
they shall, when so directed by these presents, execute and deliver by their
proper officers, agreements or other instruments supplemental hereto, which
thereafter shall form part hereof, for any one or more of the following
purposes:

         (a)  evidencing the succession of any Successors to OSI and the
              covenants of and obligations assumed by each such Successor in
              accordance with the provisions of Article 11 and the successor of
              any successor trustee in accordance with the provisions of Article
              10;

         (b)  making any additions to, deletions from or alterations of the
              provisions of this agreement or the Voting Rights, the Exchange
              Right or the Automatic Exchange Rights which, in the opinion of
              the Trustee and its counsel, will not be prejudicial to the
              interests of the Holders as a whole or are in the opinion of
              counsel to the

                                       29
<PAGE>   30

              Trustee necessary or advisable in order to incorporate, reflect or
              comply with any legislation the provisions of which apply to OSI,
              PTI Holdco, the Trustee or this agreement;

         (c)  to implement or give effect to any assignment or assumption made
              pursuant to Section 14.9 hereof; and

         (d)  for any other purposes not inconsistent with the provisions of
              this agreement, including without limitation to make or evidence
              any amendment or modification to this agreement as contemplated
              hereby, provided that, in the opinion of the Trustee and its
              counsel, the rights of the Trustee and the Holders as a whole will
              not be prejudiced thereby.

                                   ARTICLE 13
                                   TERMINATION

13.1     TERM

         The Trust created by this agreement shall continue until the earliest
to occur of the following events:

         (a)  no outstanding Exchangeable Shares are held by a Holder;

         (b)  each of PTI Holdco and OSI elects in writing to terminate the
              Trust and such termination is approved by the Holders of the
              Exchangeable Shares in accordance with Section 9.1 of the
              Exchangeable Share Provisions; and

         (c)  21 years after the death of the last survivor of the descendants
              of Her Majesty Queen Elizabeth II of the United Kingdom of Great
              Britain and Northern Ireland living on the date of the creation of
              the Trust;

whereupon OSI may repurchase the Voting Share for cancellation, at par value.

13.2     SURVIVAL OF AGREEMENT

         This agreement shall survive any termination of the Trust and shall
continue until there are no Exchangeable Shares outstanding held by a Holder;
provided, however, that the provisions of Articles 8 and 9 hereof shall survive
any such termination of this agreement.

                                   ARTICLE 14
                                     GENERAL

14.1     SEVERABILITY

         If any provision of this agreement is held to be invalid, illegal or
unenforceable, the validity, legality or enforceability of the remainder of this
agreement shall not in any way be affected or impaired thereby, and the
agreement shall be carried out as nearly as possible in accordance with its
original terms and conditions.

                                       30
<PAGE>   31

14.2     INUREMENT

         This agreement shall be binding upon and inure to the benefit of the
parties hereto and their respective successors and permitted assigns and to the
benefit of the Holders.

14.3     NOTICES TO PARTIES

         All notices and other communications between the parties hereunder
shall be in writing and shall be deemed to have been given if delivered
personally or by confirmed telecopy to the parties at the following addresses
(or at such other address for such party as shall be specified in like notice):

         (a)      if to OSI:

                  Oil States International, Inc.
                  Three Allen Center
                  333 Clay Street, Suite 333460
                  Houston, Texas 77002

                  Attention:  Cindy B. Taylor
                  Fax:  (713) 652-0499

                  with a copy to:

                  Donahue, Ernst & Young LLP
                  1000 Ernst & Young Tower
                  440 - 2nd Avenue S.W.
                  P.O. Box 2258, Station M
                  Calgary, Alberta  T2P 5E5

                  Attention:  Richard Peters
                  Fax:  (403) 206-5525

         (b)      if to PTI Holdco to:

                  892489 Alberta Inc.
                  Three Allen Center
                  333 Clay Street, Suite 333460
                  Houston, Texas 77002

                  Attention:  Cindy B. Taylor
                  Fax:  (713) 652-0499

                                       31
<PAGE>   32

         (c)      if to the Trustee to:

                  Montreal Trust Company of Canada
                  Suite 600, 530 - 8th Avenue S.W.
                  Calgary, Alberta
                  T2P 3S8

                  Attention:  Manager, Stock Transfer Services
                  Fax:  (403) 267-6529

         Any notice or other communication given personally shall be deemed to
have been given and received upon delivery thereof, and if given by telecopy
shall be deemed to have been given and received on the date of receipt thereof
unless such day is not a Business Day in which case it shall be deemed to have
been given and received upon the immediately following Business Day.

14.4     NOTICE TO HOLDERS

         Any and all notices to be given and any documents to be sent to any
Holders may be given or sent to the address of such Holder shown on the register
of Holders of Exchangeable Shares in any manner permitted by the Exchangeable
Share Provisions and shall be deemed to be received (if given or sent in such
manner) at the time specified in such Exchangeable Share Provisions, the
provisions of which Exchangeable Share Provisions shall apply mutatis mutandis
to notices or documents as aforesaid sent to such Holders.

14.5     RISK OF PAYMENTS BY POST

         Whenever payments are to be made or documents are to be sent to any
Holder by the Trustee, by PTI Holdco or by OSI or by such Holder to the Trustee
or to OSI or PTI Holdco, the making of such payment or sending of such document
sent through the mail shall be at the risk of PTI Holdco or OSI, in the case of
payments made or documents sent by the Trustee or PTI Holdco or OSI, and the
Holder, in the case of payments made or documents sent by the Holder.

14.6     COUNTERPARTS

         This agreement may be executed in counterparts, each of which shall be
deemed an original, but all of which taken together shall constitute one and the
same instrument.

14.7     JURISDICTION

         This agreement shall be construed and enforced in accordance with the
laws of the Province of Alberta and the federal laws of Canada applicable
therein.

14.8     ATTORNMENT

         OSI agrees that any action or proceeding arising out of or relating to
this agreement may be instituted in the courts of Alberta, waives any objection
which it may have now or hereafter to the venue of any such action or
proceeding, irrevocably submits to the jurisdiction of such courts in any such
action or proceeding, agrees to be bound by any judgment of such courts and
agrees

                                       32
<PAGE>   33

not to seek, and hereby waives, any review of the merits of any such judgment by
the courts of any other jurisdiction and hereby appoints PTI Holdco at its
registered office in the Province of Alberta as OSI's attorney for service of
process.

14.9     PERMITTED ASSIGNMENT

         OSI may assign any or all of its rights and obligations under this
Agreement to OSI ULC, provided that each of OSI and OSI ULC shall thereafter,
jointly and severally, be liable for the performance by OSI ULC of the
obligations of OSI pursuant to this Agreement. Any and all of the obligations of
OSI may be performed and satisfied by OSI ULC, except that nothing in this
Section 14.9 will permit any change to the rights, privileges, restrictions and
conditions attaching to the Voting Share or Exchangeable Shares or to the
Exchange Right or Automatic Exchange Rights.

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

OIL STATES INTERNATIONAL, INC.         COMPUTERSHARE TRUST COMPANY OF CANADA

Per:  /s/ CINDY B. TAYLOR              Per: /s/ S. WILSON
      ----------------------------     -----------------------------------------

892489 ALBERTA INC.

Per:  /s/ SANDY SLATOR                 Per: /s/ COLIN W. PETRYK
      ----------------------------     -----------------------------------------

                                       33
<PAGE>   34

                                   APPENDIX A
                   TO THE VOTING AND EXCHANGE TRUST AGREEMENT

                                       34
<PAGE>   35

  ALBERTA                                    RESTATED ARTICLES OF INCORPORATION
  REGISTRIES                                           Business Corporations Act
                                                                     Section 174
--------------------------------
1.     NAME OF CORPORATION                        2.     CORPORATE ACCESS NUMBER
--------------------------------------------------------------------------------

       892489 ALBERTA INC.                                208924894
--------------------------------------------------------------------------------
3.     THE CLASSES, AND ANY MAXIMUM NUMBER OF SHARES THAT THE CORPORATION IS
       AUTHORIZED TO ISSUE:

       See attached Schedule - "Share Capital".

4.     RESTRICTIONS ON SHARE TRANSFERS (IF ANY):

       The transfer of shares is restricted; no share of the Corporation may be
       transferred without the approval of the Board of Directors.

5      NUMBER, OR MINIMUM AND MAXIMUM NUMBER, OF DIRECTORS:

       Minimum:   One (1);    Maximum:  Fifteen (15)

6.     IF THE CORPORATION IS RESTRICTED FROM CARRYING ON A CERTAIN BUSINESS OR
       RESTRICTED TO CARRYING ON A CERTAIN BUSINESS, SPECIFY THE RESTRICTION(S):

       None.

7.     OTHER PROVISIONS (IF ANY):

       See attached Schedule - "Other Rules and Provisions".

       THE RESTATED ARTICLES OF INCORPORATION CORRECTLY SET OUT ABOVE, WITHOUT
       SUBSTANTIVE CHANGE REPRESENT THE ARTICLES OF INCORPORATION AS AMENDED AND
       SUPERSEDE THE ORIGINAL ARTICLES OF INCORPORATION.

       --------------------------------------------
        Signature of Director/Authorized Officer

                                                            FEBRUARY ___, 2001
       --------------------------------------------    -------------------------
                  Title (please print)                         Date

                                       35
<PAGE>   36

                                  SHARE CAPITAL

A.       The Corporation is authorized to issue an unlimited number of Common
         Shares and an unlimited number of Exchangeable Shares.

I.       PROVISIONS ATTACHING TO THE COMMON SHARES

         The Common Shares ("Common Shares") in the capital of the Corporation
         shall have attached thereto the following rights, privileges,
         restrictions and conditions:

         DIVIDENDS

         Subject to the prior rights of the Exchangeable Shares and any other
         shares ranking prior to the Common Shares, holders of Common Shares
         have a right to receive dividends when declared by the Board of
         Directors out of property of the Corporation legally available
         therefor.

         LIQUIDATION

         Subject to the prior rights of the Exchangeable Shares and any other
         shares ranking prior to the Common Shares, the holders of Common Shares
         shall, upon any liquidation, dissolution or winding-up of the
         Corporation, whether voluntary or involuntary, or other distribution of
         the assets of the Corporation for the purpose of winding-up its
         affairs, be entitled to receive the remaining property and assets of
         the Corporation.

         VOTING

         The holders of the Common Shares shall be entitled to receive notice of
         and to attend all meetings of shareholders (other than separate
         meetings of other classes or series of shares), and shall be entitled
         to one vote for each Common Share held.

II.      PROVISIONS ATTACHING TO THE EXCHANGEABLE SHARES

         The Exchangeable Shares in the capital of the Corporation shall have
         the following rights, privileges, restrictions and conditions:

                                    ARTICLE 1
                                 INTERPRETATION

1.1      For the purposes of these rights, privileges, restrictions and
         conditions:

                                       36
<PAGE>   37

         "Act" means the Business Corporations Act (Alberta), as amended,
         consolidated or reenacted from time to time.

         "Aggregate Equivalent Vote Amount" means, with respect to any matter,
         proposition or question on which holders of OSI Common Stock are
         entitled to vote, consent or otherwise act, the product of (i) the
         number of Exchangeable Shares then issued and outstanding and held by
         holders (other than OSI and its Subsidiaries) multiplied by (ii) the
         number of votes to which a holder of one share of OSI Common Stock is
         entitled with respect to such matter, proposition or question.

         "Automatic Redemption Date" means the date for the automatic redemption
         by the Corporation of Exchangeable Shares pursuant to Article 7 of
         these share provisions, which date shall be the first to occur of (a)
         the date, if any, selected pursuant to this clause (a) by the Board of
         Directors of the Corporation, such date to be no earlier than the fifth
         anniversary of the Effective Date, (b) the date selected by the Board
         of Directors of the Corporation (such date to be no earlier than the
         third or fourth anniversary of the Effective Date of the Arrangement)
         at a time when less than 10% or 20%, respectively, of the number of
         Exchangeable Shares issuable on the Effective Date (other than
         Exchangeable Shares held by OSI and its Subsidiaries, and as such
         number of shares may be adjusted as deemed appropriate by the Board of
         Directors to give effect to any subdivision or consolidation of or
         stock dividend on the Exchangeable Shares, any issuance or distribution
         of rights to acquire Exchangeable Shares or securities exchangeable for
         or convertible into or carrying rights to acquire Exchangeable Shares,
         any issue or distribution of other securities or rights or evidences of
         indebtedness or assets, or any other capital reorganization or other
         transaction involving or affecting the Exchangeable Shares), are
         outstanding, (c) the date the Board of Directors of the Corporation
         selects if an OSI Control Transaction occurs and the Board of Directors
         determines, in good faith and in its sole discretion, that it is not
         reasonable to substantially replicate the terms and conditions of the
         Exchangeable Shares in connection with such OSI Control Transaction and
         that the redemption of all but not less than all of the outstanding
         Exchangeable Shares is commercially or legally necessary to enable the
         completion of such OSI Control Transaction in accordance with its
         terms, (d) the Business Day following the day on which the holders of
         Exchangeable Shares fail to pass, at any meeting or vote, a resolution
         regarding any matter on which the holders of Exchangeable Shares are
         entitled to vote as shareholders of the Corporation and which has been
         proposed by the Board of Directors of the Corporation, provided that
         this clause (d) shall not apply to any resolution to amend the
         Exchangeable Share Provisions, the Support Agreement or the Voting and
         Exchange Trust

                                       37
<PAGE>   38

         Agreement, or (e) the Business Day following the day on which the
         holders of Exchangeable Shares fail to take the necessary action at a
         meeting or other vote of holders of Exchangeable Shares, if and to the
         extent such action is required, to approve or disapprove, as
         applicable, any change to, or in the rights of the holders of,
         Exchangeable Shares, if the approval or disapproval, as applicable, of
         such change would be required to maintain the economic and legal
         equivalence of the Exchangeable Shares and the OSI Common Stock.

         "Board of Directors" means the board of directors of the Corporation
         and any committee thereof acting within its authority.

         "Business Day" means any day other than a Saturday, a Sunday or a day
         when banks are not open for business in either or both of Houston,
         Texas and Edmonton, Alberta.

         "Canadian Dollar Equivalent" means in respect of an amount expressed in
         a foreign currency (the "Foreign Currency Amount") at any date the
         product obtained by multiplying:

         (a)  the Foreign Currency Amount by,

         (b)  the noon spot exchange rate on such date for such foreign currency
              expressed in Canadian dollars as reported by the Bank of Canada
              or, in the event such spot exchange rate is not available, such
              spot exchange rate on such date for such foreign currency
              expressed in Canadian dollars as may be deemed by the Board of
              Directors to be appropriate for such purpose.

         "Combination Agreement" means the agreement so entitled dated as of
         July 31, 2000 by and among OSI, HWC Energy Services, Inc., Merger
         Sub-HWC, Inc., Sooner Inc., Merger Sub-Sooner, Inc. and PTI.

         "Common Shares" means the common shares in the capital of the
         Corporation.

         "Current Market Price" means, in respect of a share of OSI Common Stock
         on any date, the average of the closing price per share (computed and
         rounded to the third decimal point) of shares of OSI Common Stock
         during the period of 20 consecutive trading days ending not more than
         five trading days before such date on the New York Stock Exchange, or,
         if OSI Common Stock is not then traded on the New York Stock Exchange,
         on such other principal U.S. stock exchange or automated quotation
         system on which the OSI Common Stock is then listed or quoted, as the
         case may be, as may be selected by the Board of Directors for such
         purpose; provided, however, that if, in the opinion of

                                       38
<PAGE>   39

         the Board of Directors the public distribution or trading activity of
         OSI Common Stock during such period does not create a market which
         reflects the fair market value of a share of OSI Common Stock, then the
         Current Market Price of a share of OSI Common Stock shall be determined
         by the Board of Directors based upon the advice of such qualified
         independent financial advisors as the Board of Directors may deem to be
         appropriate, and provided further any such selection, opinion or
         determination by the Board of Directors shall be conclusive and
         binding.

         "Effective Date" has the meaning ascribed thereto in the Plan of
         Arrangement.

         "Exchangeable Share Consideration" means, with respect to each
         Exchangeable Share, for any acquisition of or redemption of or
         distribution of assets of the Corporation in respect of or purchase
         pursuant to these share provisions, the Plan of Arrangement, the
         Support Agreement or the Voting and Exchange Trust Agreement:

         (a)  the Current Market Price of one share of OSI Common Stock
              deliverable in connection with such action;

         (b)  a cheque or cheques payable at par at any branch of the bankers of
              the payor in the amount of all declared, payable and unpaid, and
              all undeclared but payable, cash dividends deliverable in
              connection with such action; and

         (c)  such stock or other property constituting any declared and unpaid,
              and all undeclared but payable, non-cash dividends deliverable in
              connection with such action,

         provided that (i) that part of the consideration which represents (a)
         above, shall be fully paid and satisfied by the delivery of one share
         of OSI Common Stock that is freely tradeable, such share to be duly
         issued as a fully paid and non-assessable share, (ii) that part of the
         consideration which represents (c), above, unpaid shall be fully paid
         and satisfied by delivery of such non-cash items, and (iii) any such
         consideration shall be delivered free and clear of any lien, claim,
         encumbrance, security interest or adverse claim or interest less any
         tax required to be deducted and withheld therefrom and without
         interest.

         "Exchangeable Share Price" means, for each Exchangeable Share, an
         amount equal to the aggregate of:

         (a)  the Current Market Price of a share of OSI Common Stock; plus

                                       39
<PAGE>   40

         (b)  an additional amount equal to the full amount of all cash
              dividends declared, payable and unpaid on such Exchangeable Share;
              plus

         (c)  an additional amount equal to all dividends declared and payable
              on OSI Common Stock which have not been declared on Exchangeable
              Shares in accordance herewith; plus

         (d)  an additional amount representing non-cash dividends declared,
              payable and unpaid on such Exchangeable Share.

         "Exchangeable Shares" means the Exchangeable Shares of the Corporation
         having the rights, privileges, restrictions and conditions set forth
         herein.

         "freely tradeable", with respect to OSI Common Stock, means freely
         transferable under Canadian provincial securities laws and U.S. federal
         and state securities laws (pursuant to an effective resale shelf
         registration statement or otherwise and assuming the reasonable
         cooperation of the holder or recipient of OSI Common Stock in
         connection with any required resale shelf registration statement),
         except to the extent restrictions arise by reason of a person being a
         "control person" of OSI for the purposes of Canadian provincial
         securities laws or an "affiliate" of OSI for the purposes of United
         States federal or state securities laws, provided any trades in such
         securities are conducted through the facilities of a stock exchange
         outside Canada.

         "Liquidation Amount" has the meaning provided in Section 5.1.

         "Liquidation Call Right" has the meaning provided in the Restated
         Articles of Incorporation of the Corporation.

         "Liquidation Call Purchase Price" has the meaning provided in the
         Restated Articles of Incorporation of the Corporation.

         "Liquidation Date" has the meaning provided in Section 5.1.

         "OSI" means Oil States International, Inc., a corporation organized and
         existing under the laws of the State of Delaware and includes any
         successor corporation or any corporation in which the holders of OSI
         Common Stock hold securities resulting from the application of Section
         2.7 of the Support Agreement.

         "OSI Call Notice" has the meaning provided in Section 6.3.

                                       40
<PAGE>   41

         "OSI Common Stock" means the shares of common stock of OSI, with a par
         value of U.S. $0.01 per share, having voting rights of one vote per
         share, and any other securities resulting from the application of
         Section 2.7 of the Support Agreement.

         "OSI Control Transaction" means any merger or amalgamation involving
         OSI, any tender offer for OSI, and any material sale of shares or
         rights or interests therein or thereto by OSI or similar transactions,
         or any proposal to do so, provided that upon completion of any such
         transaction the holders of OSI Common Stock immediately before such
         transaction would hold, directly or indirectly, less than 50% of the
         voting securities, or securities exchangeable or exercisable for or
         convertible into voting securities, of the merged or amalgamated
         corporation, the offeror or the purchaser, as the case may be.

         "OSI Dividend Declaration Date" means the date on which the board of
         directors of OSI declares any dividend on the OSI Common Stock.

         "OSI Special Share" means the one share of Special Voting Stock of OSI,
         with a par value of U.S. $0.01, and having voting rights at meetings of
         holders of OSI Common Stock equal to the Aggregate Equivalent Voting
         Amount.

         "OSI ULC" has the meaning provided in the Voting and Exchange Trust
         Agreement.

         "PTI" means PTI Group Inc., a corporation organized and existing under
         the Act.

         "Plan of Arrangement" means the plan of arrangement involving and
         affecting PTI and the holders of common shares and options, PTI Amalco
         and the holders of its shares, the Corporation and the holders of its
         shares, OSI and OSI ULC under section 186 of the Act contemplated in
         the Combination Agreement, as further amended and restated from time to
         time.

         "Purchase Price" has the meaning provided in Section 6.3.

         "Redemption Call Purchase Price" has the meaning provided in the
         Restated Articles of Incorporation of the Corporation.

         "Redemption Call Right" has the meaning provided in the Restated
         Articles of Incorporation of the Corporation.

         "Redemption Price" has the meaning provided in Section 7.1.

                                       41
<PAGE>   42

         "Retracted Shares" has the meaning provided in subsection 6.1 (a).

         "Retraction Call Right" has the meaning provided in subsection 6.1 (c).

         "Retraction Date" has the meaning provided in subsection 6.1 (b).

         "Retraction Price" has the meaning provided in Section 6. 1.

         "Retraction Request" has the meaning provided in Section 6.1.

         "Subsidiary", in relation to any person, means any body corporate,
         partnership, joint venture, association or other entity of which more
         than 50% of the total voting power of shares of stock or units of
         ownership or beneficial interest entitled to vote in the election of
         directors (or members of a comparable governing body) is owned or
         controlled, directly or indirectly, by such person.

         "Support Agreement" means the Support Agreement between OSI and the
         Corporation, made as of the Effective Date.

         "Transfer Agent" means the duly appointed transfer agent for the time
         being of the Exchangeable Shares at its offices in each of Calgary,
         Alberta and Toronto, Ontario.

         "Trustee" means the Trustee appointed under the Voting and Exchange
         Trust Agreement, and any successor trustee.

         "Voting and Exchange Trust Agreement" means the Voting and Exchange
         Trust Agreement among the Corporation, OSI and the Trustee, made as of
         the Effective Date.

                                    ARTICLE 2
                         RANKING OF EXCHANGEABLE SHARES

2.1      The Exchangeable Shares shall be entitled to a preference over the
         Common Shares and any other shares ranking junior to the Exchangeable
         Shares, with respect to the payment of dividends and the distribution
         of assets in the event of the liquidation, dissolution or winding-up of
         the Corporation, whether voluntary or involuntary, or any other
         distribution of the assets of the Corporation among its shareholders
         for the purpose of winding-up its affairs.

                                       42
<PAGE>   43

                                    ARTICLE 3
                                    DIVIDENDS

3.1      Subject to Section 3.2 below, a holder of an Exchangeable Share shall
         be entitled to receive and the Board of Directors shall, subject to
         applicable law, on each OSI Dividend Declaration Date, declare a
         dividend on each Exchangeable Share:

         (a)  in the case of a cash dividend declared on the OSI Common Stock,
              in an amount in cash for each Exchangeable Share in U.S. dollars,
              or the Canadian Dollar Equivalent thereof on the OSI Dividend
              Declaration Date, in each case corresponding to the cash dividend
              declared on each share of OSI Common Stock;

         (b)  in the case of a stock dividend declared on OSI Common Stock to be
              paid in shares of OSI Common Stock, in such number of Exchangeable
              Shares for each Exchangeable Share as is equal to the number of
              shares of OSI Common Stock to be paid on each share of OSI Common
              Stock; or

         (c)  in the case of a dividend declared on the OSI Common Stock in
              property other than cash or OSI Common Stock, in such type and
              amount of property for each Exchangeable Share as is the same as
              or economically equivalent to (to be determined by the Board of
              Directors as contemplated by Section 3.6 hereof) the type and
              amount of property declared as a dividend on each share of OSI
              Common Stock.

         Such dividends shall be paid out of money, assets or property of the
         Corporation properly applicable to the payment of dividends, or out of
         authorized but unissued shares of the Corporation, as applicable.

3.2      In the case of a stock dividend declared on the OSI Common Stock to be
         paid in shares of OSI Common Stock, in lieu of declaring the stock
         dividend contemplated by Section 3.1(b) on the Exchangeable Shares, the
         Board of Directors may, in its discretion and subject to applicable
         law, subdivide, redivide or change (the "subdivision") each issued and
         unissued Exchangeable Share on the basis that each Exchangeable Share
         before the subdivision becomes a number of Exchangeable Shares as is
         equal to the sum of (i) a share of OSI Common Stock and (ii) the number
         of shares of OSI Common Stock to be paid as a stock dividend on each
         share of OSI Common Stock. In such instance, and notwithstanding any
         other provision hereof, such subdivision shall become effective on the
         effective date specified in Section 3.4 hereof without any further act
         or formality on the part of the Board of

                                       43
<PAGE>   44

         Directors or of the holders of Exchangeable Shares. For greater
         certainty, no approval of the holders of Exchangeable Shares to an
         amendment to the articles of the Corporation shall be required to give
         effect to such subdivision.

3.3      Cheques of the Corporation payable at par at any branch of the bankers
         of the Corporation shall be issued in respect of any cash dividends
         contemplated by subsection 3.1 (a) hereof and the sending of such a
         cheque to each holder of an Exchangeable Share (less any tax required
         to be deducted and withheld from such dividends paid or credited by the
         Corporation) shall satisfy the cash dividends represented thereby
         unless the cheque is not paid on presentation. Certificates registered
         in the name of the registered holder of Exchangeable Shares shall be
         issued or transferred in respect of any stock dividends contemplated by
         subsections 3.1 (b) or (c) hereof and the sending of such a certificate
         to each holder of an Exchangeable Share shall satisfy the stock
         dividend represented thereby or dividend payable in other securities
         represented thereby. Such other type and amount of property in respect
         of any dividends contemplated by subsection 3.1 (c) hereof shall be
         issued, distributed or transferred by the Corporation in such manner as
         it shall determine and the issuance, distribution or transfer thereof
         by the Corporation to each holder of an Exchangeable Share shall
         satisfy the dividend represented thereby. In all cases, any such
         dividends shall be subject to any reduction or adjustment for tax
         required to be deducted and withheld from such dividends, and the
         Corporation shall be entitled to liquidate some of the property which
         would otherwise be deliverable in payment of such dividends to a
         particular holder of Exchangeable Shares to fund any statutory
         withholding obligation. No holder of an Exchangeable Share shall be
         entitled to recover by action or other legal process against the
         Corporation any dividend which is represented by a cheque that has not
         been duly presented to the Corporation's bankers for payment or which
         otherwise remains unclaimed for a period of six years from the date on
         which such dividend was payable.

3.4      The record date for the determination of the holders of Exchangeable
         Shares entitled to receive payment of, and the payment date for, any
         dividend declared on the Exchangeable Shares under Section 3.1 hereof
         shall be the same dates as the record date and payment date,
         respectively, for the corresponding dividend declared on the OSI Common
         Stock. The record date for the determination of the holders of
         Exchangeable Shares entitled to receive Exchangeable Shares in
         connection with any subdivision of Exchangeable Shares under Section
         3.2 hereof and the effective date of such subdivision shall be the same
         dates as the record date and payment date, respectively, for the
         corresponding stock dividend declared on the OSI Common Stock.

                                       44
<PAGE>   45

3.5      If on any payment date for any dividends declared on the Exchangeable
         Shares under Section 3.1 hereof the dividends are not paid in full on
         all of the Exchangeable Shares then outstanding, any such dividends
         which remain unpaid shall be paid on a subsequent date or dates
         determined by the Board of Directors on which the Corporation shall
         have sufficient moneys, assets or property properly applicable to the
         payment of such dividends.

3.6      The Board of Directors shall determine, in good faith and in its sole
         discretion, economic equivalence for the purposes of Sections 3.1 and
         3.2 hereof, and each such determination shall be conclusive and binding
         on the Corporation and its shareholders. In making each such
         determination, the following factors shall, without excluding other
         factors determined by the Board of Directors to be relevant, be
         considered by the Board of Directors:

         (a)  in the case of any stock dividend or other distribution payable in
              shares of OSI Common Stock, the number of such shares issued in
              proportion to the number of shares of OSI Common Stock previously
              outstanding;

         (b)  in the case of the issuance or distribution of any rights, options
              or warrants to subscribe for or purchase shares of OSI Common
              Stock (or securities exchangeable for or convertible into or
              carrying rights to acquire shares of OSI Common Stock), the
              relationship between the exercise price of each such right, option
              or warrant and the Current Market Price of a share of OSI Common
              Stock;

         (c)  in the case of the issuance or distribution of any other form of
              property (including without limitation any shares or securities of
              OSI of any class other than OSI Common Stock, any rights, options
              or warrants other than those referred to in Section 3.6(b) above,
              any evidences of indebtedness of OSI or any assets of OSI), the
              relationship between the fair market value (as determined by the
              Board of Directors in the manner above contemplated) of such
              property to be issued or distributed with respect to each
              outstanding share of OSI Common Stock and the Current Market Price
              of a share of OSI Common Stock; and

         (d)  in all such cases, the general taxation consequences of the
              relevant event to holders of Exchangeable Shares to the extent
              that such consequences may differ from the taxation consequences
              to holders of OSI Common Stock as a result of differences between
              taxation laws of Canada and the United States (except for any
              differing consequences arising as a result

                                       45
<PAGE>   46

              of differing marginal taxation rates and without regard to the
              individual circumstances of holders of Exchangeable Shares).

3.7      Except as provided in this Article 3, the holders of Exchangeable
         Shares shall not be entitled to receive dividends in respect thereof.

                                    ARTICLE 4
                              CERTAIN RESTRICTIONS

4.1      So long as any of the Exchangeable Shares are outstanding, the
         Corporation shall not at any time without, but may at any time with,
         the approval of the holders of the Exchangeable Shares given as
         specified in Article 9 of these share provisions:

         (a)  pay any dividends on the Common Shares, or any other shares
              ranking junior to the Exchangeable Shares, other than stock
              dividends payable in any such other shares ranking junior to the
              Exchangeable Shares;

         (b)  redeem or purchase or make any capital distribution in respect of
              Common Shares or any other shares ranking junior to the
              Exchangeable Shares with respect to the payment of dividends or on
              any liquidation distribution;

         (c)  redeem or purchase any other shares of the Corporation ranking
              equally with the Exchangeable Shares with respect of the payment
              of dividends or on any liquidation distribution;

         (d)  issue any Exchangeable Shares other than by way of stock dividends
              to holders of Exchangeable Shares or as contemplated by the
              Support Agreement; or

         (e)  amend the articles or by-laws of the Corporation, in either case
              in any manner that would affect the rights or privileges of the
              holders of the Exchangeable Shares.

         The restrictions in subsections 4.1(a), 4.1(b) and 4.1(c) above shall
         not apply if all dividends on the outstanding Exchangeable Shares
         corresponding to dividends declared with a record date on or following
         the effective date of the Plan of Arrangement on the OSI Common Stock
         shall have been declared on the Exchangeable Shares and paid in full.
         Nothing herein shall be interpreted to restrict the Corporation from
         issuing additional Common Shares to OSI or any Subsidiary of OSI.

                                       46
<PAGE>   47

                                    ARTICLE 5
                           DISTRIBUTION ON LIQUIDATION

5.1      In the event of the liquidation, dissolution or winding-up of the
         Corporation or any other distribution of the assets of the Corporation
         among its shareholders for the purpose of winding-up its affairs,
         provided that neither OSI nor OSI ULC shall have exercised the
         Liquidation Call Right, a holder of Exchangeable Shares shall be
         entitled, subject to applicable law, to receive from the assets of the
         Corporation in respect of each Exchangeable Share held by such holder
         on the effective date of such liquidation, dissolution or winding-up
         (the "Liquidation Date"), before any distribution of any part of the
         assets of the Corporation to the holders of the Common Shares or any
         other shares ranking junior to the Exchangeable Shares, an amount equal
         to the Exchangeable Share Price applicable on the last Business Day
         prior to the Liquidation Date (the "Liquidation Amount") in accordance
         with Section 5.2. In connection with payment of the Liquidation Amount,
         the Corporation shall be entitled to liquidate some of the OSI Common
         Stock which would otherwise be deliverable as Exchangeable Share
         Consideration to the particular holder of Exchangeable Shares in order
         to fund any statutory withholding tax obligation.

5.2      Within three Business Days after the Liquidation Date, and subject to
         the exercise by OSI or OSI ULC of the Liquidation Call Right, the
         Corporation shall cause to be delivered to the holders of the
         Exchangeable Shares the Liquidation Amount for each such Exchangeable
         Share upon presentation and surrender of the certificates representing
         such Exchangeable Shares, together with such other documents and
         instruments as may be required to effect a transfer of Exchangeable
         Shares under applicable law and the by-laws of the Corporation and such
         additional documents and instruments as the Transfer Agent may
         reasonably require, at the registered office of the Corporation or at
         any office of the Transfer Agent as may be specified by the Corporation
         in Schedule A hereto or by notice to the holders of the Exchangeable
         Shares (provided that such presentation and surrender shall be valid if
         made at the office of the Transfer Agent, if any, in the province in
         which such holder is listed on the books of the Corporation). Payment
         of the total Liquidation Amount for such Exchangeable Shares shall be
         made by delivery to each holder, at the address of the holder recorded
         in the securities register of the Corporation for the Exchangeable
         Shares or by holding for pick up by the holder at the registered office
         of the Corporation or at any office of the Transfer Agent as may be
         specified by the Corporation in Schedule A hereto or by notice to the
         holders of Exchangeable Shares (provided that such delivery shall be
         made to the holder at its address recorded in the securities register
         of the Corporation or at the office of the transfer

                                       47
<PAGE>   48

         agent, if any, in the province in which the address of the holder
         recorded in the securities register of the Corporation is located), on
         behalf of the Corporation of the Exchangeable Share Consideration
         representing the total Liquidation Amount. On and after the Liquidation
         Date, the holders of the Exchangeable Shares shall cease to be holders
         of such Exchangeable Shares and shall not be entitled to exercise any
         of the rights of holders in respect thereof, other than the right to
         receive their proportionate part of the total Liquidation Amount,
         unless payment of the total Liquidation Amount for such Exchangeable
         Shares shall not be made upon presentation and surrender of share
         certificates in accordance with the foregoing provisions, in which case
         the rights of the holders shall remain unaffected until the total
         Liquidation Amount has been paid in the manner hereinbefore provided.
         The Corporation shall have the right at any time on or after the
         Liquidation Date to deposit or cause to be deposited the Exchangeable
         Share Consideration in respect of the Exchangeable Shares represented
         by certificates that have not at the Liquidation Date been surrendered
         by the holders thereof in a custodial account or for safe keeping, in
         the case of non-cash items, with any chartered bank or trust company in
         Canada. Upon such deposit being made, the rights of the holders of
         Exchangeable Shares after such deposit shall be limited to receiving
         their proportionate part of the total Liquidation Amount for such
         Exchangeable Shares so deposited, against presentation and surrender of
         the said certificates held by them, respectively, in accordance with
         the foregoing provisions. Upon such payment or deposit of such
         Exchangeable Share Consideration, the holders of the Exchangeable
         Shares shall thereafter be considered and deemed for all purposes to be
         the holders of the OSI Common Stock delivered to them. Notwithstanding
         the foregoing, until such payment or deposit of such Exchangeable Share
         Consideration, the holder shall be deemed to still be a holder of
         Exchangeable Shares for purposes of all voting rights with respect
         thereto under the Voting and Exchange Trust Agreement.

5.3      After the Corporation has satisfied its obligations to pay the holders
         of the Exchangeable Shares the Liquidation Amount per Exchangeable
         Share, such holders shall not be entitled to share in any further
         distribution of the assets of the Corporation.

5.4      If OSI or OSI ULC exercises the Liquidation Call Right, each holder of
         Exchangeable Shares shall be obligated to sell the Exchangeable Shares
         held by such holder to OSI or OSI ULC, as the case may be, on the
         Liquidation Date on payment to such holder by OSI or OSI ULC, as the
         case may be, of the Exchangeable Share Consideration representing the
         Liquidation Call Purchase Price for each Exchangeable Share.

                                       48
<PAGE>   49

                                    ARTICLE 6
                   RETRACTION OF EXCHANGEABLE SHARES BY HOLDER

6.1      A holder of Exchangeable Shares shall be entitled at any time after the
         effectiveness of a Registration Statement under the Securities Act of
         1933 registering the issuance of shares of OSI Common Stock issuable
         pursuant to the provisions attaching to the Exchangeable Shares or
         prior thereto with the written consent of the Corporation, subject to
         applicable law and the exercise by OSI or OSI ULC of the Retraction
         Call Right (which, if exercised by OSI or OSI ULC, shall be binding on
         the holder of Exchangeable Shares) and otherwise upon compliance with
         the provisions of this Article 6, to require the Corporation to redeem
         any or all of the Exchangeable Shares registered in the name of such
         holder for an amount equal to the Exchangeable Share Price applicable
         on the last Business Day prior to the Retraction Date (the "Retraction
         Price") which as set forth in Section 6.4, shall be fully paid and
         satisfied by the delivery by or on behalf of the Corporation of the
         Exchangeable Share Consideration representing such holder's Retraction
         Price. In connection with payment of the Retraction Price, the
         Corporation shall be entitled to liquidate some of the OSI Common Stock
         that would otherwise be deliverable as Exchangeable Share Consideration
         to the particular holder of Exchangeable Shares in order to fund any
         statutory withholding tax obligation. To effect such redemption, the
         holder shall present and surrender at the registered office of the
         Corporation or at any office of the Transfer Agent as may be specified
         by the Corporation in Schedule A hereto or by notice to the holders of
         Exchangeable Shares the certificate or certificates representing the
         Exchangeable Shares which the holder desires to have the Corporation
         redeem, together with such other documents and instruments as may be
         required to effect a transfer of Exchangeable Shares under applicable
         law and the by-laws of the Corporation and such additional documents
         and instruments as the Transfer Agent may reasonably require, and
         together with a duly executed statement (the "Retraction Request") in
         the form of Schedule "A" hereto or in such other form as may be
         acceptable to the Corporation:

         (a)  specifying that the holder desires to have all or any number
              specified therein of the Exchangeable Shares represented by such
              certificate or certificates (the "Retracted Shares") redeemed by
              the Corporation;

         (b)  stating the Business Day on which the holder desires to have the
              Corporation redeem the Retracted Shares (the "Retraction Date"),
              provided that the Retraction Date shall be not less than three
              Business Days nor more than 10 Business Days after the date on
              which the Retraction Request is received by the

                                       49
<PAGE>   50

              Corporation and further provided that, in the event that no such
              Business Day is specified by the holder in the Retraction Request,
              the Retraction Date shall be deemed to be the tenth Business Day
              after the date on which the Retraction Request is received by the
              Corporation; and

         (c)  acknowledging the overriding right (the "Retraction Call Right")
              of OSI or OSI ULC to purchase all but not less than all the
              Retracted Shares directly from the holder and that the Retraction
              Request shall be deemed to be a revocable offer by the holder to
              sell the Retracted Shares in accordance with the Retraction Call
              Right on the terms and conditions set out in Section 6.3 below.

6.2      Subject to the exercise by OSI or OSI ULC of the Retraction Call Right,
         upon receipt by the Corporation or the Transfer Agent in the manner
         specified in Section 6.1 hereof of a certificate or certificates
         representing the number of Exchangeable Shares which the holder desires
         to have the Corporation redeem, together with a Retraction Request, and
         provided that the Retraction Request is not revoked by the holder in
         the manner specified in Section 6.7, the Corporation shall redeem the
         Retracted Shares effective at the close of business on the Retraction
         Date and shall cause to be delivered to such holder the total
         Retraction Price with respect to such shares in accordance with Section
         6.4 hereof. If only a part of the Exchangeable Shares represented by
         any certificate are redeemed or purchased by OSI or OSI ULC pursuant to
         the Retraction Call Right, a new certificate for the balance of such
         Exchangeable Shares shall be issued to the holder at the expense of the
         Corporation.

6.3      Upon receipt by the Corporation of a Retraction Request, the
         Corporation shall immediately notify OSI and OSI ULC thereof. In order
         to exercise the Retraction Call Right, OSI or OSI ULC must notify the
         Corporation in writing of its determination to do so (the "OSI Call
         Notice") within two Business Days of such notification. If OSI or OSI
         ULC does not so notify the Corporation within such two Business Days,
         the Corporation will notify the holder as soon as possible thereafter
         that neither OSI nor OSI ULC will exercise the Retraction Call Right.
         If OSI or OSI ULC delivers the OSI Call Notice within such two Business
         Days, and provided that the Retraction Request is not revoked by the
         holder in the manner specified in Section 6.7 hereof, the Retraction
         Request shall thereupon be considered only to be an offer by the holder
         to sell the Retracted Shares to OSI or OSI ULC, as the case may be, in
         accordance with the Retraction Call Right. In such event, the
         Corporation shall not redeem the Retracted Shares and OSI or OSI ULC,
         as the case may be, shall purchase from such holder and

                                       50
<PAGE>   51

         such holder shall sell to OSI or OSI ULC, as the case may be, on the
         Retraction Date the Retracted Shares for a purchase price per share
         (the "Purchase Price") equal to the Retraction Price, which as set
         forth in Section 6.4 hereof, shall be fully paid and satisfied by the
         delivery by or on behalf of OSI or OSI ULC, as the case may be, of the
         Exchangeable Share Consideration representing such holder's Purchase
         Price. For the purposes of completing a purchase pursuant to the
         Retraction Call Right, OSI or OSI ULC, as the case may be, shall
         deposit with the Transfer Agent, on or before the Retraction Date, the
         Exchangeable Share Consideration representing the total Purchase Price.
         Provided that such Exchangeable Share Consideration has been so
         deposited with the Transfer Agent, the closing of the purchase and sale
         of the Retracted Shares pursuant to the Retraction Call Right shall be
         deemed to have occurred as at the close of business on the Retraction
         Date and, for greater certainty, no redemption by the Corporation of
         such Retracted Shares shall take place on the Retraction Date. In the
         event that OSI or OSI ULC, as the case may be, does not deliver a OSI
         Call Notice within two Business Days or otherwise comply with these
         Exchangeable Share provisions in respect thereto, and provided that
         Retraction Request is not revoked by the holder in the manner specified
         in Section 6.7 hereof, the Corporation shall redeem the Retracted
         Shares on the Retraction Date and in the manner otherwise contemplated
         in this Article 6.

6.4      Subject to receipt by the Corporation of the Retracted Shares, OSI or
         OSI ULC, as the case may be, the Corporation, OSI or OSI ULC, as the
         case may be, shall deliver or cause the Transfer Agent to deliver to
         the relevant holder, at the address of the holder recorded in the
         securities register of the Corporation for the Exchangeable Shares or
         at the address specified in the holder's Retraction Request or by
         holding for pick up by the holder at the registered office of the
         Corporation or at any office of the Transfer Agent as may be specified
         by the holder in Schedule A hereto, in each case on or before two
         Business Days after the Retraction Date, the Exchangeable Share
         Consideration representing the total Retraction Price or the total
         Purchase Price, as the case may be, and such delivery of such
         Exchangeable Share Consideration to the Transfer Agent shall be deemed
         to be payment of and shall satisfy and discharge all liability for the
         total Retraction Price or total Purchase Price, as the case may be,
         except as to any cheque included therein which is not paid on due
         presentation.

6.5      On and after the close of business on the Retraction Date, the holder
         of the Retracted Shares shall cease to be a holder of such Retracted
         Shares and shall not be entitled to exercise any of the rights of a
         holder in respect thereof, other than the right to receive such
         holder's proportionate part of the total Retraction Price or total
         Purchase Price, as the case may be, unless upon presentation and
         surrender of certificates in accordance with the foregoing provisions,
         payment of the total Retraction Price or the total Purchase Price,

                                       51
<PAGE>   52

         as the case may be, shall not be made, in which case the rights of such
         holder shall remain unaffected until the Exchangeable Share
         Consideration representing the total Retraction Price or the total
         Purchase Price, as the case may be, has been paid in the manner
         hereinbefore provided. On and after the close of business on the
         Retraction Date, provided that presentation and surrender of
         certificates and payment of the Exchangeable Share Consideration
         representing the total Retraction Price or the total Purchase Price, as
         the case may be, has been made in accordance with the foregoing
         provisions, the holder of the Retracted Shares so redeemed by the
         Corporation or purchased by OSI or OSI ULC shall thereafter be
         considered and deemed for all purposes to be a holder of the OSI Common
         Stock delivered to it. Notwithstanding the foregoing, until such
         payment of such Exchangeable Share Consideration to the holder, the
         holder shall be deemed to still be a holder of Exchangeable Shares for
         purposes of all voting rights with respect thereto under the Voting and
         Exchange Trust Agreement.

6.6      Notwithstanding any other provision of this Article 6, the Corporation
         shall not be obligated to redeem Retracted Shares specified by a holder
         in a Retraction Request to the extent that such redemption of Retracted
         Shares would be contrary to liquidity or solvency requirements or other
         provisions of applicable law. If the Corporation believes that on any
         Retraction Date it would not be permitted by any of such provisions to
         redeem the Retracted Shares tendered for redemption on such date, and
         provided that neither OSI nor OSI ULC shall have exercised the
         Retraction Call Right with respect to the Retracted Shares, the
         Corporation shall only be obligated to redeem Retracted Shares
         specified by a holder in a Retraction Request to the extent of the
         maximum number that may be so redeemed (rounded down to a whole number
         of shares) as would not be contrary to such provisions and shall notify
         the holder as soon as is reasonably practical but in any event not
         later than one Business Day prior to the Retraction Date as to the
         number of Retracted Shares which will not be redeemed by the
         Corporation. In any case in which the redemption by the Corporation of
         Retracted Shares would be contrary to liquidity or solvency
         requirements or other provisions of applicable law, the Corporation
         shall redeem Retracted Shares in accordance with Section 6.2 of these
         share provisions on a pro rata basis and shall issue to each holder of
         Retracted Shares a new certificate, at the expense of the Corporation,
         representing the Retracted Shares not redeemed by the Corporation
         pursuant to Section 6.2 hereof. Provided that the Retraction Request is
         not revoked by the holder in the manner specified in Section 6.7
         hereof, the holder of any such Retracted Shares not redeemed by the

                                       52
<PAGE>   53

         Corporation pursuant to Section 6.2 hereof as a result of liquidity or
         solvency requirements or applicable law shall be deemed by giving the
         Retraction Request to require OSI or OSI ULC, as the case may be, to
         purchase such Retracted Shares from such holder on the Retraction Date
         or as soon as practicable thereafter on payment by OSI or OSI ULC, as
         the case may be, to such holder of the Purchase Price for each such
         Retracted Share, all as more specifically provided in the Voting and
         Exchange Trust Agreement, and OSI or OSI ULC shall make such purchase.

6.7      A holder of Retracted Shares may, by notice in writing given by the
         holder to the Corporation before the close of business on the Business
         Day immediately preceding the Retraction Date, withdraw its Retraction
         Request in which event such Retraction Request shall be null and void
         and, for greater certainty, the revocable offer constituted by the
         Retraction Request to sell the Retracted Shares to OSI or OSI ULC, as
         the case may be, shall be deemed to have been revoked.

                                    ARTICLE 7
              REDEMPTION OF EXCHANGEABLE SHARES BY THE CORPORATION

7.1      Subject to applicable law, and if neither OSI or OSI ULC exercises the
         Redemption Call Right (which, if exercised, shall be binding on the
         holders of Exchangeable Shares), the Corporation shall on the Automatic
         Redemption Date redeem the whole of the then outstanding Exchangeable
         Shares for an amount equal to the Exchangeable Share Price applicable
         on the last Business Day prior to the Automatic Redemption Date (the
         "Redemption Price") which, as set forth in Section 7.3 hereof, shall be
         fully paid and satisfied by the delivery by or on behalf of the
         Corporation of the Exchangeable Share Consideration representing the
         total Redemption Price. In connection with payment of the Exchangeable
         Share Consideration representing the Redemption Price, the Corporation
         shall be entitled to liquidate some of the OSI Common Stock which would
         otherwise be deliverable as Exchangeable Share Consideration to the
         particular holder of Exchangeable Shares in order to fund any statutory
         withholding tax obligation.

7.2      In any case of a redemption of Exchangeable Shares under this Article
         7, the Corporation, or the Transfer Agent on behalf of the Corporation,
         shall, at least 60 days before an Automatic Redemption Date described
         in clause (a) or (b) of the definition of Automatic Redemption Date or
         at least such number of days before an Automatic Redemption Date
         described in clause (c), (d) or (e) of the definition of Automatic
         Redemption Date as the Board of Directors of the Corporation may

                                       53
<PAGE>   54

         determine to be reasonably practicable in the circumstances, send or
         cause to be sent to each registered holder of Exchangeable Shares a
         notice in writing of the redemption or possible redemption by the
         Corporation or the purchase by OSI or OSI ULC under the Redemption Call
         Right, as the case may be, of the Exchangeable Shares held by such
         holder. Such notice shall set out the Redemption Price or the
         Redemption Call Purchase Price, as the case may be, the Automatic
         Redemption Date and, if applicable, particulars of the Redemption Call
         Right. In the case of any notice given in connection with a possible
         Automatic Redemption Date as described in clause (c), (d) or (e) of the
         definition of Automatic Redemption Date, such notice will be given
         contingently and will be withdrawn if the contingency does not occur.

7.3      On or after the Automatic Redemption Date, and subject to the exercise
         by OSI or OSI ULC of the Redemption Call Right, the Corporation shall
         cause to be delivered to the holders of the Exchangeable Shares to be
         redeemed the Exchangeable Share Consideration representing the
         Redemption Price for each such Exchangeable Share upon presentation and
         surrender at the registered office of the Corporation or at any office
         of the Transfer Agent as may be specified by the Corporation in such
         notice of the certificates representing such Exchangeable Shares,
         together with such other documents and instruments as may be required
         to effect a transfer of Exchangeable Shares under applicable law and
         the by-laws of the Corporation and such additional documents and
         instruments as the Transfer Agent may reasonably require (provided that
         such presentation and surrender shall be deemed to be valid if made at
         the office of the Transfer Agent, if any, in the province in which the
         address of the holder of Exchangeable Shares is recorded on the books
         of the Corporation). Payment of the total Redemption Price for such
         Exchangeable Shares shall be made by delivery to each holder, at the
         address of the holder recorded in the securities register or at any
         office of the Transfer Agent as may be specified by the Corporation in
         such notice, on behalf of the Corporation, of the Exchangeable Share
         Consideration representing the total Redemption Price (provided that if
         payment is made by delivery of the Exchangeable share Consideration to
         the Transfer Agent, such delivery shall be made at the office of the
         Transfer Agent, if any, in the province in which the address of the
         holder of Exchangeable Shares is recorded on the books of the
         Corporation). On and after the Automatic Redemption Date, the holders
         of the Exchangeable Shares called for redemption shall cease to be
         holders of such Exchangeable Shares and shall not be entitled to
         exercise any of the rights of holders in respect thereof, other than
         the right to receive their proportionate part of the Exchangeable Share
         Consideration representing the total Redemption Price, unless payment
         of the Exchangeable Share Consideration representing the total
         Redemption Price for such Exchangeable Shares shall not be made

                                       54
<PAGE>   55

         upon presentation and surrender of certificates in accordance with the
         foregoing provisions, in which case the rights of the holders shall
         remain unaffected until the Exchangeable Share Consideration
         representing the total Redemption Price has been paid in the manner
         hereinbefore provided. The Corporation shall have the right at any time
         after the sending of notice of its intention to redeem the Exchangeable
         Shares as aforesaid to deposit or cause to be deposited the
         Exchangeable Share Consideration with respect to the Exchangeable
         Shares so called for redemption, or of such of the said Exchangeable
         Shares represented by certificates that have not at the date of such
         deposit been surrendered by the holders thereof in connection with such
         redemption, in a custodial account or for safe keeping, in the case of
         non-cash items, with any chartered bank or trust company in Canada
         named in such notice. Upon the later of such deposit being made and the
         Automatic Redemption Date, the Exchangeable Shares in respect whereof
         such deposit shall have been made shall be redeemed and the rights of
         the holders thereof after such deposit or Automatic Redemption Date, as
         the case may be, shall be limited to receiving their proportionate part
         of the Exchangeable Share Consideration representing the total
         Redemption Price for such Exchangeable Shares so deposited, against
         presentation and surrender of the said certificates held by them,
         respectively, in accordance with the foregoing provisions. Upon such
         payment or deposit of such Exchangeable Share Consideration, the
         holders of the Exchangeable Shares shall thereafter be considered and
         deemed for all purposes to be holders of the OSI Common Stock delivered
         to them. Notwithstanding the foregoing, until such payment or deposit
         of such Exchangeable Share Consideration is made, the holder shall be
         deemed to still be a holder of Exchangeable Shares for purposes of all
         voting rights with respect thereto under the Voting and Exchange Trust
         Agreement.

7.4      If OSI or OSI ULC exercises the Redemption Call Right, each holder of
         Exchangeable Shares shall be obligated to sell all the Exchangeable
         Shares held by such holder to OSI or OSI ULC, as the case may be, on
         the Automatic Redemption Date against payment to such holder by OSI or
         OSI ULC of the Exchangeable Share Consideration representing the
         Redemption Call Purchase Price for each such share.

                                    ARTICLE 8
                                  VOTING RIGHTS

8.1      Except as required by applicable law and the provisions hereof, the
         holders of the Exchangeable Shares shall not be entitled as such to
         receive notice of or to attend any meeting of the shareholders of the
         Corporation or to vote at any such meeting.

                                       55
<PAGE>   56

                                    ARTICLE 9
                             AMENDMENT AND APPROVAL

9.1      The rights, privileges, restrictions and conditions attaching to the
         Exchangeable Shares may be added to, changed or removed but, except as
         hereinafter provided, only with the approval of the holders of the
         Exchangeable Shares given as hereinafter specified.

9.2      Any approval given by the holders of the Exchangeable Shares to add to,
         change or remove any right, privilege, restriction or condition
         attaching to the Exchangeable Shares or any other matter requiring the
         approval or consent of the holders of the Exchangeable Shares shall be
         deemed to have been sufficiently given if it shall have been given in
         accordance with applicable law subject to a minimum requirement that
         such approval be evidenced by resolution passed by not less than 66
         2/3% of the votes cast on such resolution by persons represented in
         person or by proxy at a meeting of holders of Exchangeable Shares
         (excluding Exchangeable Shares beneficially owned by OSI or its
         Subsidiaries) duly called and held at which the holders of at least 50%
         of the outstanding Exchangeable Shares at that time are present or
         represented by proxy. If at any such meeting the holders of at least
         50% of the outstanding Exchangeable Shares at that time are not present
         or represented by proxy within one-half hour after the time appointed
         for such meeting, then the meeting shall be adjourned to such date not
         less than 10 days thereafter and to such time and place as may be
         designated by the Chairman of such meeting. At such adjourned meeting,
         the holders of Exchangeable Shares present or represented by proxy
         thereat may transact the business for which the meeting was originally
         called and a resolution passed thereat by the affirmative vote of not
         less than 66 2/3% of the votes cast on such resolution by persons
         represented in person or by proxy at such meeting (excluding
         Exchangeable Shares beneficially owned by OSI or its Subsidiaries)
         shall constitute the approval or consent of the holders of the
         Exchangeable Shares. For the purposes of this Section, any spoiled
         votes, illegible votes, defective votes and abstinences shall be deemed
         to be votes not cast.

                                   ARTICLE 10
             RECIPROCAL CHANGES, ETC. IN RESPECT OF OSI COMMON STOCK

10.1  (a)     Each holder of an Exchangeable Share acknowledges that the Support
              Agreement provides, in part, that OSI will not:

              (i)   issue or distribute shares of OSI Common Stock (or
                    securities exchangeable for or convertible into or carrying
                    rights to acquire shares of OSI Common Stock) to the holders
                    of all or substantially all of the then outstanding shares
                    of OSI Common Stock by way of stock dividend or other
                    distribution; or

                                       56
<PAGE>   57

              (ii)  issue or distribute rights, options or warrants to the
                    holders of all or substantially all of the then outstanding
                    shares of OSI Common Stock entitling them to subscribe for
                    or to purchase shares of OSI Common Stock (or securities
                    exchangeable for or convertible into or carrying rights to
                    acquire shares of OSI Common Stock); or

              (iii) issue or distribute to the holders of all or substantially
                    all of the then outstanding shares of OSI Common Stock (A)
                    shares or securities of OSI of any class other than OSI
                    Common Stock (other than shares convertible into or
                    exchangeable for or carrying rights to acquire shares of OSI
                    Common Stock), (B) rights, options or warrants other than
                    those referred to in subsection 11.1 (a) (ii) above, (C)
                    evidences of indebtedness of OSI or (D) assets of OSI;

              unless

              (iv)  one or both of OSI and the Corporation is permitted under
                    applicable law to issue or distribute the economic
                    equivalent on a per share basis of such rights, options,
                    warrants, securities, shares, evidences of indebtedness or
                    other assets to the holders of the Exchangeable Shares; and

              (v)   one or both of OSI and the Corporation shall issue or
                    distribute the economic equivalent on a per share basis of
                    such rights, options, warrants, securities, shares,
                    evidences of indebtedness or other assets simultaneously to
                    the holders of the Exchangeable Shares.

         (b)  Each holder of an Exchangeable Share acknowledges that the Support
              Agreement further provides, in part, that OSI will not:

              (i)   subdivide, redivide or change the then outstanding shares of
                    OSI Common Stock into a greater number of shares of OSI
                    Common Stock; or

              (ii)  reduce, combine or consolidate or change the then
                    outstanding shares of OSI Common Stock into a lesser number
                    of shares of OSI Common Stock; or

                                       57
<PAGE>   58

              (iii) reclassify or otherwise change the shares of OSI Common
                    Stock or effect an amalgamation, merger, reorganization or
                    other transaction involving or affecting the shares of OSI
                    Common Stock;

         unless

              (iv)  the Corporation is permitted under applicable law to
                    simultaneously make the same or an economically equivalent
                    change to, or in the rights of the holders of, the
                    Exchangeable Shares; and

              (v)   the same or an economically equivalent change is
                    simultaneously made to, or in the rights of the holders of,
                    the Exchangeable Shares.

         The Support Agreement further provides, in part, that, with the
         exception of certain ministerial amendments, the aforesaid provisions
         of the Support Agreement shall not be changed without the approval of
         the holders of the Exchangeable Shares given in accordance with Article
         9 of these share provisions.

                                   ARTICLE 11
               ACTIONS BY THE CORPORATION UNDER SUPPORT AGREEMENT

11.1     The Corporation will take all such actions and do all such things as
         shall be necessary or advisable to perform and comply with and to
         ensure performance and compliance by OSI with all provisions of the
         Support Agreement, the Voting Trust and Exchange Agreement and OSI's
         Certificate of Incorporation applicable to the Corporation and OSI,
         respectively, in accordance with the terms thereof including, without
         limitation, taking all such actions and doing all such things as shall
         be necessary or advisable to enforce to the fullest extent possible for
         the direct benefit of the Corporation all rights and benefits in favour
         of the Corporation under or pursuant thereto.

11.2     The Corporation shall not propose, agree to or otherwise give effect to
         any amendment to, or waiver or forgiveness of its rights or obligations
         under, the Support Agreement, the Voting Trust and Exchange Agreement
         or OSI's Certificate of Incorporation without the approval of the
         holders of the Exchangeable Shares given in accordance with Section 9.2
         hereof other than such amendments, waivers and/or forgiveness as may be
         necessary or advisable for the purpose of:

                                       58
<PAGE>   59

         (a)  adding to the covenants of the other party or parties to such
              agreement for the protection of the Corporation or the holders of
              Exchangeable Shares; or

         (b)  making such provisions or modifications not inconsistent with such
              agreement or certificate as may be necessary or desirable with
              respect to matters or questions arising thereunder which, in the
              opinion of the Board of Directors, it may be expedient to make,
              provided that the Board of Directors shall be of the opinion,
              after consultation with counsel, that such provisions and
              modifications will not be prejudicial to the interests of the
              holders of the Exchangeable Shares; or

         (c)  making such changes in or corrections to such agreement or
              certificate which, on the advice of counsel to the Corporation,
              are required for the purpose of curing or correcting any ambiguity
              or defect or inconsistent provision or clerical omission or
              mistake or manifest error contained therein, provided that the
              Board of Directors shall be of the opinion, after consultation
              with counsel, that such changes or corrections will not be
              prejudicial to the interests of the holders of the Exchangeable
              Shares.

                                   ARTICLE 12
                                     LEGEND

12.1     The certificates evidencing the Exchangeable Shares shall contain or
         have affixed thereto a legend, in form and on terms approved by the
         Board of Directors, with respect to the Support Agreement, the
         provisions of the Articles of the Corporation relating to the
         Liquidation Call Right, the Retraction Call Right and the Redemption
         Call Right, and the Voting and Exchange Trust Agreement (including the
         provisions with respect to the voting rights and exchange provisions
         thereunder).

                                   ARTICLE 13
                                  MISCELLANEOUS

13.1     Any notice, request or other communication to be given to the
         Corporation by a holder of Exchangeable Shares shall be in writing and
         shall be valid and effective if given by mail (postage prepaid) or by
         telecopy or by delivery to the registered office of the Corporation and
         addressed to the attention of the President. Any such notice, request
         or other communication, if given by mail, telecopy or delivery, shall
         only be deemed to have been given and received upon actual receipt
         thereof by the Corporation.

                                       59
<PAGE>   60

13.2     Any presentation and surrender by a holder of Exchangeable Shares to
         the Corporation or the Transfer Agent of certificates representing
         Exchangeable Shares in connection with the liquidation, dissolution or
         winding-up of the Corporation or the retraction, redemption or exchange
         of Exchangeable Shares shall be made by registered mail (postage
         prepaid) or by delivery to the registered office of the Corporation or
         to such office of the Transfer Agent as may be specified by the
         Corporation, in each case addressed to the attention of the President
         of the Corporation. Any such presentation and surrender of certificates
         shall only be deemed to have been made and to be effective upon actual
         receipt thereof by the Corporation or the Transfer Agent, as the case
         may be, and the method of any such presentation and surrender of
         certificates shall be at the sole risk of the holder.

13.3     Any notice, request or other communication to be given to a holder of
         Exchangeable Shares by or on behalf of the Corporation shall be in
         writing and shall be valid and effective if given by mail (postage
         prepaid) or by delivery to the address of the holder recorded in the
         securities register of the Corporation or, in the event of the address
         of any such holder not being so recorded, then at the last address of
         such holder known to the Corporation. Any such notice, request or other
         communication, if given by mail, shall be deemed to have been given and
         received on the fifth Business Day following the date of mailing and,
         if given by delivery, shall be deemed to have been given and received
         on the date of delivery. Accidental failure or omission to give any
         notice, request or other communication to one or more holders of
         Exchangeable Shares shall not invalidate or otherwise alter or affect
         any action or proceeding to be or intended to be taken by the
         Corporation.

13.4     For greater certainty, the Corporation shall not be required for any
         purpose under these share provisions to recognize or take account of
         persons who are not so recorded in such securities register.

13.5     All Exchangeable Shares acquired by the Corporation upon the redemption
         or retraction thereof shall be cancelled.

13.6     For greater certainty, any payments to the holders of Exchangeable
         Shares shall be net of applicable taxes, if any, and the payor shall
         not be obliged to gross up or increase the amount of such payment which
         would otherwise be made to take into account such taxes. Any such taxes
         which have been withheld or deducted by the payor thereof shall be
         remitted to the applicable tax authority within the time required for
         such remittance.

                                       60
<PAGE>   61

                                  SCHEDULE "A"

                               RETRACTION REQUEST

To the Corporation, Oil States International, Inc. ("OSI") and 3045843 Nova
Scotia Company ("OSI ULC")

         This request is given pursuant to Article 6 of the provisions (the
"Share Provisions") attaching to the Exchangeable Shares of the Corporation and
all capitalized words and expressions used in this request which are defined in
the Share Provisions have the meaning attributed to such words and expressions
in such Share Provisions.

         The undersigned hereby notifies the Corporation that, subject to the
Retraction Call Right referred to below, the undersigned requests the
Corporation to redeem in accordance with Article 6 of the Share Provisions:

               all share(s) represented by the accompanying certificate(s); or
         ----

               ____________ share(s) only.
         ----

         The undersigned hereby notifies the Corporation that the Retraction
         Date shall be ___________________.
                             date

         NOTE:    The Retraction Date must be a Business Day and must not be
                  less than three Business Days nor more than 10 Business Days
                  after the date upon which this notice and the accompanying
                  shares are received at the registered office of the
                  Corporation or at any office of the Transfer Agent as may be
                  specified in this Retraction Request. In the event that no
                  such Business Day is correctly specified above, the Retraction
                  Date shall be deemed to be the tenth Business Day after the
                  date on which this request is received by the Corporation.

         The undersigned acknowledges the Retraction Call Right of OSI and OSI
ULC (as defined in the Share Provisions) to purchase all but not less than all
the Retracted Shares from the undersigned and that this request shall be deemed
to be a revocable offer by the undersigned to sell the Retracted Shares to OSI
or OSI ULC, as the case may be, in accordance with the Retraction Call Right on
the Retraction Date for the Retraction Price and on the other terms and
conditions set out in Section 6.3 of the Share Provisions. If neither OSI nor
OSI ULC, as the case may be, determines to exercise the Retraction Call Right,
the Corporation will notify the undersigned of such fact as soon as possible.
This retraction request, and offer to sell the Retracted Shares to OSI or OSI
ULC, as the case may be, may be revoked and withdrawn by the undersigned

                                       61
<PAGE>   62

by notice in writing given to the Corporation at any time before the close of
business on the Business Date immediately preceding the Retraction Date.

         The undersigned acknowledges that if, as a result of liquidity or
solvency provisions of applicable law, the Corporation is unable to redeem all
Retracted Shares, the undersigned will be deemed to have exercised the Exchange
Right (as defined in the Voting and Exchange Trust Agreement) so as to require
OSI to purchase, or cause OSI ULC to purchase, the unredeemed Retracted Shares.

         The undersigned hereby represents and warrants to the Corporation, OSI
and OSI ULC that the undersigned has good title to, and owns, the share(s)
represented by the accompanying certificate free and clear of all liens, claims,
encumbrances, security interests and adverse claims or interests.

---------------   ------------------------              ----------------------
Date              Signature of Shareholder              Guarantee of Signature

---      Please check box if the legal or beneficial owner of the Retracted
         Shares is a non-resident of Canada.

---      Please check box if the securities and any cheque(s) or other non-cash
         assets resulting from the retraction of the Retracted Shares are to be
         held for pick-up by the shareholder at the principal transfer offices
         of Montreal Trust Company of Canada (the "Transfer Agent") in Calgary,
         Alberta, failing which the securities and any cheque(s) or other
         non-cash assets will be delivered to the shareholder in accordance with
         the share provisions.

---      Please check box if the securities and any cheque(s) or other non-cash
         assets resulting from the retraction of the Retracted Shares are to be
         held for pick-up by the shareholder at the principal transfer offices
         of Montreal Trust Company of Canada (the "Transfer Agent") in Toronto,
         Ontario, failing which the securities and any cheque(s) or other
         non-cash assets will be delivered to the shareholder in accordance with
         the share provisions.

NOTE:    This panel must be completed and the accompanying certificate, together
         with such additional documents as the Transfer Agent may require, must
         be deposited with the Transfer Agent at its principal transfer offices
         in Calgary, Alberta or Toronto, Ontario. The securities and any
         cheque(s) or other non-cash assets resulting from the retraction or
         purchase of the Retracted Shares will be issued and registered in, and
         made payable to, or transferred into, respectively, the name of the
         shareholder as it appears on the register of the Corporation and the
         securities, cheque (s) and other non-cash assets resulting from such

                                       62
<PAGE>   63

         retraction or purchase will be delivered to the shareholder in
         accordance with the Share Provisions.

---------------------------------------             ---------------------
Name of Person in Whose Name Securities or                  Date
Cheque(s) or Other Non-cash Assets Are To Be
Registered, Issued or Delivered (please print)

---------------------------------------             ---------------------
Street Address or P.O. Box Signature of Shareholder

---------------------------------------             ---------------------
City, Province    Signature Guaranteed by

NOTE:    If this retraction request is for less than all of the share(s)
         represented by the accompanying certificate, a certificate representing
         the remaining shares of the Corporation will be issued and registered
         in the name of the shareholder as it appears on the register of the
         Corporation or its lawful transferee.

                                       63
<PAGE>   64

                            OTHER RULES OR PROVISIONS

1.1      Meetings

         Meetings of shareholders of the Corporation shall be held in the
         location determined by the directors of the Corporation, and may be
         held in Houston, Texas, or at any location within Alberta.

1.2      Definitions

         Unless there is something in the subject matter or context inconsistent
         therewith in Sections 1.3, 1.4 and 1.5 below, the following terms shall
         have the respective meanings set out below and grammatical variations
         of such terms shall have corresponding meanings:

         "Act" means the Business Corporations Act (Alberta), as amended;

         "Automatic Redemption Date" has the meaning provided in the
         Exchangeable Share Provisions;

         "Business Day" has the meaning provided in the Exchangeable Share
         Provisions;

         "Exchangeable Share Consideration" has the meaning provided in the
         Exchangeable Share Provisions;

         "Exchangeable Share Price" has the meaning provided in the Exchangeable
         Share Provisions;

         "Exchangeable Share Provisions" means the rights, privileges,
         restrictions and conditions attaching to the Exchangeable Shares;

         "Exchangeable Shares" means the Exchangeable Shares in the capital of
         the Corporation;

         "Liquidation Call Purchase Price" has the meaning provided in Section
         1.3;

         "Liquidation Call Right" has the meaning provided in Section 1.3;

         "Liquidation Date" has the meaning provided in the Exchangeable Share
         Provisions;

         "OSI" has the meaning provided in the Exchangeable Share Provisions;

                                       64
<PAGE>   65

         "OSI Common Stock" has the meaning provided in the Exchangeable Share
         Provisions;

         "Redemption Call Purchase Price" has the meaning provided in Section
         1.4;

         "Redemption Call Right" has the meaning provided in Section 1.4;

         "Subsidiary" has the meaning provided in the Exchangeable Share
         Provisions;

         "Transfer Agent" means the duly appointed transfer agent for the time
         being of the Exchangeable Shares, and, if there is more than one such
         transfer agent, then the principal Canadian transfer agent; and

         "Voting and Exchange Trust Agreement" has the meaning provided in the
          Exchangeable Share Provisions.

1.3      Liquidation Call Right

         (a)  OSI or OSI ULC shall have the overriding right (the "Liquidation
              Call Right"), in the event of and notwithstanding any proposed
              liquidation, dissolution or winding-up of the Corporation as
              referred to in Article 5 of the Exchangeable Share Provisions, to
              purchase directly from all but not less than all of the holders
              (other than OSI or any Subsidiary thereof) of Exchangeable Shares
              on the Liquidation Date all but not less than all of the
              Exchangeable Shares held by such holders on payment by OSI or OSI
              ULC to each holder of the Exchangeable Share Price applicable on
              the last Business Day prior to the Liquidation Date (the
              "Liquidation Call Purchase Price") in accordance with subsection
              1.3(c). In the event of the exercise of the Liquidation Call Right
              by OSI or OSI ULC, each holder shall be obligated to sell all the
              Exchangeable Shares held by such holder to OSI or OSI ULC on the
              Liquidation Date on payment by OSI or OSI ULC to the holder of the
              Liquidation Call Purchase Price for each such share.

         (b)  To exercise the Liquidation Call Right, OSI or OSI ULC must notify
              the Corporation's Transfer Agent in writing, as agent for the
              holders of Exchangeable Shares, and the Corporation of OSI's or
              OSI ULC's intention to exercise such right at least 55 days before
              the Liquidation Date in the case of a voluntary liquidation,
              dissolution or winding-up of the Corporation and at least five
              Business Days before the Liquidation Date in the case of an
              involuntary liquidation, dissolution or winding-up of the

                                       65
<PAGE>   66

              Corporation. The Transfer Agent will notify the holders of
              Exchangeable Shares as to whether or not OSI or OSI ULC has
              exercised the Liquidation Call Right forthwith after the expiry of
              the date by which the same may be exercised by OSI or OSI ULC. If
              OSI or OSI ULC exercises the Liquidation Call Right, on the
              Liquidation Date OSI or OSI ULC will purchase and the holders will
              sell all of the Exchangeable Shares then outstanding for a price
              per share equal to the Liquidation Call Purchase Price.

         (c)  For the purposes of completing the purchase of the Exchangeable
              Shares pursuant to the Liquidation Call Right, OSI or OSI ULC
              shall deposit with the Transfer Agent, on or before the
              Liquidation Date, the Exchangeable Share Consideration
              representing the total Liquidation Call Purchase Price. Provided
              that such Exchangeable Share Consideration has been so deposited
              with the Transfer Agent, on and after the Liquidation Date, the
              right of each holder of Exchangeable Shares will be limited to
              receiving such holder's proportionate part of the total
              Liquidation Call Purchase Price payable by OSI or OSI ULC, without
              interest, upon presentation and surrender by the holder of
              certificates representing the Exchangeable Shares held by such
              holder and the holder shall, on and after the Liquidation Date, be
              considered and deemed for all purposes to be the holder of the OSI
              Common Stock delivered to such holder. Upon surrender to the
              Transfer Agent of a certificate or certificates representing
              Exchangeable Shares, together with such other documents and
              instruments as may be required to effect a transfer of
              Exchangeable Shares under the Act and the by-laws of the
              Corporation and such additional documents and instruments as the
              Transfer Agent may reasonably require, the holder of such
              surrendered certificate or certificates shall be entitled to
              receive in exchange therefor, and the Transfer Agent on behalf of
              OSI shall deliver to such holder, the Exchangeable Share
              Consideration to which such holder is entitled. If OSI or OSI ULC
              does not exercise the Liquidation Call Right in the manner
              described above, on the Liquidation Date the holders of the
              Exchangeable Shares will be entitled to receive in exchange
              therefor the liquidation price otherwise payable by the
              Corporation in connection with the liquidation, dissolution or
              winding-up of the Corporation pursuant to Article 5 of the
              Exchangeable Share Provisions. Notwithstanding the foregoing,
              until such Exchangeable Share Consideration is delivered to the
              holder, the holder shall be deemed to still be a holder of
              Exchangeable Shares for purposes of all voting rights with respect
              thereto under the Voting and Exchange Trust Agreement.

                                       66
<PAGE>   67

1.4      Redemption Call Right

         (a)  OSI and OSI ULC shall have the overriding right (the "Redemption
              Call Right"), notwithstanding any proposed redemption of the
              Exchangeable Shares by the Corporation pursuant to Article 7 of
              the Exchangeable Share Provisions, to purchase directly from all
              but not less than all of the holders (other than OSI or any
              Subsidiary thereof) of Exchangeable Shares on the Automatic
              Redemption Date all but not less than all of the Exchangeable
              Shares held by each such holder on payment by OSI or OSI ULC to
              the holder of the Exchangeable Share Price applicable on the last
              Business Day prior to the Automatic Redemption Date (the
              "Redemption Call Purchase Price") in accordance with subsection
              1.4(c). In the event of the exercise of the Redemption Call Right
              by OSI or OSI ULC, each holder shall be obligated to sell all the
              Exchangeable Shares held by the holder to OSI or OSI ULC on the
              Automatic Redemption Date on payment by OSI or OSI ULC to the
              holder of the Redemption Call Purchase Price for each such share.

         (b)  To exercise the Redemption Call Right, OSI or OSI ULC must notify
              the Transfer Agent in writing, as agent for the holders of
              Exchangeable Shares, and the Corporation of the OSI's or OSI ULC's
              intention to exercise such right not later than the date by which
              the Corporation is required to give notice of the Automatic
              Redemption Date. The Transfer Agent will notify the holders of the
              Exchangeable Shares as to whether or not OSI or OSI ULC has
              exercised the Redemption Call Right forthwith after the date by
              which the same may be exercised by OSI or OSI ULC. If OSI or OSI
              ULC exercises the Redemption Call Right, on the Automatic
              Redemption Date, OSI will purchase and the holders will sell all
              of the Exchangeable Shares then outstanding for a price per share
              equal to the Redemption Call Purchase Price.

         (c)  For the purposes of completing the purchase of the Exchangeable
              Shares pursuant to the Redemption Call Right, OSI or OSI ULC shall
              deposit with the Transfer Agent, on or before the Automatic
              Redemption Date, the Exchangeable Share Consideration representing
              the total Redemption Call Purchase Price. Provided that such
              Exchangeable Share Consideration has been so deposited with the
              Transfer Agent, on and after the Automatic Redemption Date, the
              rights of each

                                       67
<PAGE>   68

         holder of Exchangeable Shares will be limited to receiving such
         holder's proportionate part of the total Redemption Call Purchase Price
         payable by OSI or OSI ULC upon presentation and surrender by the holder
         of certificates representing the Exchangeable Shares held by such
         holder and the holder shall on and after the Automatic Redemption Date
         be considered and deemed for all purposes to be the holder of the OSI
         Common Stock delivered to such holder. Upon surrender to the Transfer
         Agent of a certificate or certificates representing Exchangeable
         Shares, together with such other documents and instruments as may be
         required to effect a transfer of Exchangeable Shares under the Act and
         the by-laws of the Corporation and such additional documents and
         instruments as the Transfer Agent may reasonably require, the holder of
         such surrendered certificate or certificates shall be entitled to
         receive in exchange therefor, and the Transfer Agent on behalf of OSI
         or OSI ULC shall deliver to such holder, the Exchangeable Share
         Consideration to which such holder is entitled. If OSI or OSI ULC does
         not exercise the Redemption Call Right in the manner described above,
         on the Automatic Redemption Date, the holders of the Exchangeable
         Shares will be entitled to receive in exchange therefor the redemption
         price otherwise payable by the Corporation in connection with the
         redemption of the Exchangeable Shares pursuant to Article 7 of the
         Exchangeable Share Provisions. Notwithstanding the foregoing, until
         such Exchangeable Share Consideration is delivered to the holder, the
         holder shall be deemed to still be a holder of Exchangeable Shares for
         purposes of all voting rights with respect thereto under the Voting and
         Exchange Trust Agreement.

1.5      Retraction Call Right

         OSI or OSI ULC shall have the overriding right, notwithstanding the
         proposed redemption of Exchangeable Shares by the Corporation pursuant
         to Article 6 of the Exchangeable Share Provisions, to purchase directly
         from the holder (other than OSI or any Subsidiary thereof) of
         Exchangeable Shares all but not less than all of the Retracted Shares
         in accordance with Section 6.3 of the Exchangeable Share Provisions.

                                       68<PAGE>   1
                                                                    EXHIBIT 10.5

                       THE 2001 EQUITY PARTICIPATION PLAN
                                       OF
                         OIL STATES INTERNATIONAL, INC.

         OIL STATES INTERNATIONAL, INC., a Delaware corporation, has adopted The
2001 Equity Participation Plan of Oil States International, Inc. (the "Plan"),
effective February 8, 2001 (the "Effective Date"), for the benefit of its
eligible employees, consultants and directors. This Plan is an amendment and
restatement of the 1996 Equity Participation Plan of CE Holdings, Inc.
("ConEmsco Plan") to be effective as provided in Section 10.4.

         The purposes of this Plan are as follows:

         (1) To provide an additional incentive for Directors, Employees and
consultants to further the growth, development and financial success of the
Company by personally benefitting through the ownership of Company stock and/or
rights which recognize such growth, development and financial success.

         (2) To enable the Company to obtain and retain the services of
Directors, Employees and consultants considered essential to the long range
success of the Company by offering them an opportunity to own stock in the
Company and/or rights which will reflect the growth, development and financial
success of the Company.

                                    ARTICLE I

                                   DEFINITIONS

         1.1 General. All references to share numbers and dollar amounts in this
Plan shall be deemed to give effect to the concurrent reverse three-for-one
split of the Common Stock to be effected on or before the Effective Date.
Wherever the following terms are used in this Plan they shall have the meaning
specified below, unless the context clearly indicates otherwise.

         1.2 Affiliate. "Affiliate" shall mean any entity that, directly or
through one or more intermediaries, is controlled by the Company or controls the
Company as determined by the Committee.

         1.3 Award Limit. "Award Limit" shall mean 400,000 shares of Common
Stock.

         1.4 Board. "Board" shall mean the Board of Directors of the Company.

         1.5 Change of Control. "Change of Control" shall mean any of the
following:

         (a) any "person" (as such term is used in Section 13(d) and 14(d) of
the Securities Exchange Act of 1934, as amended (the "Exchange Act")), (other
than a trustee or other fiduciary holding securities under an employee benefit
plan of the Company or any affiliate, SCF III, L.P., SCF IV, L.P., or any
affiliate of SCF-III, L.P. or SCF-IV, L.P. or any corporation

<PAGE>   2
owned, directly or indirectly, by the stockholders of the Company in
substantially the same proportions as their ownership of stock of the Company),
acquires "beneficial ownership" (within the meaning of Rule 13d-3 under the
Exchange Act) of securities of the Company representing 35% or more of the
combined voting power of the Company's then outstanding securities; provided,
however, that if the Company engages in a merger or consolidation in which the
Company or surviving entity in such merger or consolidation becomes a subsidiary
of another entity, then references to the Company's then outstanding securities
shall be deemed to refer to the outstanding securities of such parent entity;

         (b) a change in the composition of the Board, as a result of which
fewer than a majority of the directors are Incumbent Directors. "Incumbent
Directors" shall mean directors who either (i) are directors of the Company as
of the Effective Date, or (ii) are elected, or nominated for election, to the
Board with the affirmative votes of at least two-thirds of the Incumbent
Directors at the time of such election or nomination, but Incumbent Director
shall not include an individual whose election or nomination occurs as a result
of either (1) an actual or threatened election contest (as such terms are used
in Rule 14a-11 of Regulation 14A promulgated under the Exchange Act) or (2) an
actual or threatened solicitation of proxies or consents by or on behalf of a
person other than the Board;

         (c) the consummation of a merger or consolidation of the Company with
any other corporation, other than a merger or consolidation which would result
in the voting securities of the Company outstanding immediately prior thereto
continuing to represent (either by remaining outstanding or by being converted
into voting securities of the surviving entity (or if the surviving entity is or
shall become a subsidiary of another entity, then such parent entity)) more than
50% of the combined voting power of the voting securities of the Company (or
such surviving entity or parent entity, as the case may be) outstanding
immediately after such merger or consolidation;

         (d) the stockholders of the Company approve a plan of complete
liquidation of the Company; or

         (e) the sale or disposition (other than a pledge or similar
encumbrance) by the Company of all or substantially all of the assets of the
Company other than to a subsidiary or subsidiaries of the Company.

         1.6 Code. "Code" shall mean the Internal Revenue Code of 1986, as
amended.

         1.7 Committee. "Committee" shall mean the Board or a subcommittee of
the Board appointed as provided in Section 9.1.

         1.8 Common Stock. "Common Stock" shall mean the common stock of the
Company, par value $0.01 per share.

                                       2
<PAGE>   3
         1.9 Company. "Company" shall mean Oil States International, Inc., a
Delaware corporation.

         1.10 Deferred Stock. "Deferred Stock" shall mean Common Stock awarded
under Article VII of this Plan.

         1.11 Director. "Director" shall mean a member of the Board who is not
an Employee.

         1.12 Dividend Equivalent. "Dividend Equivalent" shall mean a right to
receive the equivalent value (in cash or Common Stock) of dividends paid on
Common Stock, awarded under Article VII of this Plan.

         1.13 Employee. "Employee" shall mean any officer or other employee (as
defined in accordance with Section 3401(c) of the Code) of the Company or of any
Affiliate or Subsidiary.

         1.14 Exchange Act. "Exchange Act" shall mean the Securities Exchange
Act of 1934, as amended.

         1.15 Fair Market Value. "Fair Market Value" of a share of Common Stock
as of a given date shall be (i) the closing price of a share of Common Stock on
the principal exchange on which shares of Common Stock are then trading, if any
(as reported in any reporting service approved by the Committee), on the trading
day previous to such date, or if shares were not traded on the trading day
previous to such date, then on the next preceding date on which a trade
occurred, or (ii) if Common Stock is not traded on an exchange but is quoted on
Nasdaq or a successor quotation system, the mean between the closing
representative bid and asked prices for the Common Stock on the trading day
previous to such date as reported by Nasdaq or such successor quotation system;
or (iii) if Common Stock is not publicly traded on an exchange and not quoted on
Nasdaq or a successor quotation system, the Fair Market Value of a share of
Common Stock as established by the Committee acting in good faith.
Notwithstanding the foregoing, the Fair Market Value of a share of Common Stock
on the date of an initial public offering of Common Stock shall be the offering
price under such initial public offering.

         1.16 Grantee. "Grantee" shall mean an Employee or consultant granted a
Performance Award, Dividend Equivalent, or Stock Payment, or an award of
Deferred Stock, under this Plan.

         1.17 Non-Qualified Stock Option. "Non-Qualified Stock Option" shall
mean an Option which is not designated as an Incentive Stock Option by the
Committee.

         1.18 Option. "Option" shall mean a stock option granted under Article
III of this Plan). An Option granted under this Plan shall, as determined by the
Committee, be either a Non-Qualified Stock Option or an Incentive Stock Option;
provided, however, that Options granted to Directors, consultants and Employees
employed by an Affiliate that is not a Subsidiary shall be Non-Qualified Stock
Options.

                                       3
<PAGE>   4
         1.19 Optionee. "Optionee" shall mean an Employee, consultant or
Director granted an Option under this Plan.

         1.20 Performance Award. "Performance Award" shall mean a performance or
incentive award, other than an Option, Restricted Stock, Deferred Stock or Stock
Payments, that is paid in cash, Common Stock or a combination of both, awarded
under Article VII of this Plan.

         1.21 Performance Objectives. "Performance Objectives" means the
objectives, if any, established by the Committee that are to be achieved with
respect to an Award granted under this Plan, which may be described in terms of
Company-wide objectives, in terms of objectives that are related to performance
of a division, subsidiary, department or function within the Company or an
Affiliate in which the Participant receiving the Award is employed or in
individual or other terms, and which will relate to the period of time
determined by the Committee. The Performance Objectives intended to qualify
under Section 162(m) of the Code shall be with respect to one or more of the
following: (i) net income; (ii) pre-tax income; (iii) operating income; (iv)
cash flow; (v) earnings per share; (vi) earnings before any one or more of the
following items: interest, taxes, depreciation or amortization; (vii) return on
equity; (viii) return on invested capital or assets; (ix) cost reductions or
savings; (x) funds from operations and (xi) appreciation in the fair market
value of the Company's common stock. Which objectives to use with respect to an
Award, the weighting of the objectives if more than one is used, and whether the
objective is to be measured against a Company-established budget or target, an
index or a peer group of companies, shall be determined by the Committee in its
discretion at the time of grant of the Award. A Performance Objective need not
be based on an increase or a positive result and may include, for example,
maintaining the status quo or limiting economic losses.

         1.22 Plan. "Plan" shall mean The 2001 Equity Participation Plan of Oil
States International, Inc.

         1.23 QDRO. "QDRO" shall mean a qualified domestic relations order as
defined by the Code or Title I of the Employee Retirement Income Security Act of
1974, as amended, or the rules thereunder.

         1.24 Restricted Stock. "Restricted Stock" shall mean Common Stock
awarded under Article VI of this Plan.

         1.25 Restricted Stockholder. "Restricted Stockholder" shall mean an
Employee or consultant granted an award of Restricted Stock under Article VI of
this Plan.

         1.26 Rule 16b-3. "Rule 16b-3" shall mean that certain Rule 16b-3 under
the Exchange Act, as such Rule may be amended from time to time.

         1.27 Stock Payment. "Stock Payment" shall mean (i) a payment in the
form of shares of Common Stock, or (ii) an option or other right to purchase
shares of Common Stock, as part of a deferred compensation arrangement, made in
lieu of all or any portion of the compensation, including without limitation,
salary, bonuses and commissions, that would otherwise become payable to an
Employee or consultant in cash, awarded under Article VII of this Plan.

                                       4
<PAGE>   5
         1.28 Subsidiary. "Subsidiary" shall mean any corporation in an unbroken
chain of corporations beginning with the Company if each of the corporations
other than the last corporation in the unbroken chain then owns stock possessing
50 percent or more of the total combined voting power of all classes of stock in
one of the other corporations in such chain.

                                   ARTICLE II

                             SHARES SUBJECT TO PLAN

         2.1  Shares Subject to Plan.

         (a) The shares of stock subject to Options, awards of Restricted Stock,
Performance Awards, Dividend Equivalents, awards of Deferred Stock, or Stock
Payments shall be Common Stock. The aggregate number of such shares which may be
issued upon exercise of such options or rights or upon any such awards under the
Plan shall not exceed three million seven hundred thousand (3,700,000). The
shares of Common Stock issuable upon exercise of such options or rights or upon
any such awards may be either previously authorized but unissued shares or
treasury shares.

         (b) The maximum number of shares which may be subject to Options,
Restricted Stock or Deferred Stock granted under the Plan to any individual in
any calendar year shall not exceed the Award Limit. The maximum value of
Performance Awards granted under the Plan to any individual in any calendar year
shall not exceed $2.5 million.

         2.2 Add-back Options and Other Rights. If any Option, or other right to
acquire shares of Common Stock under any other award under this Plan, expires or
is canceled without having been fully exercised or is exercised in whole or in
part for cash as permitted by this Plan, the number of shares subject to such
Option or other right but as to which such Option or other right was not
exercised prior to its expiration or cancellation or was exercised for cash may
again be optioned, granted or awarded hereunder, subject to the limitations of
Section 2.1. If any share of Restricted Stock is forfeited by the Grantee, such
share may again be optioned, granted or awarded hereunder, subject to the
limitations of Section 2.1.

                                       5
<PAGE>   6
                                   ARTICLE III

                               GRANTING OF OPTIONS

         3.1 Eligibility. Any Employee or consultant selected by the Committee
pursuant to Section 3.4(a)(i) shall be eligible to be granted an Option. Each
Director of the Company shall be granted Options at the times and in the manner
set forth in Section 3.4(d).

         3.2 Disqualification for Stock Ownership. No person may be granted an
Incentive Stock Option under this Plan if such person, at the time the Incentive
Stock Option is granted, owns stock possessing more than ten percent (10%) of
the total combined voting power of all classes of stock of the Company or any
then existing Subsidiary unless such Incentive Stock Option conforms to the
applicable provisions of Section 422 of the Code,

         3.3 Qualification of Incentive Stock Options. No Incentive Stock Option
shall be granted unless such Option, when granted, qualifies as an "incentive
stock option" under Section 422 of the Code. No Incentive Stock Option shall be
granted to any person who is not an employee of the Company or a Subsidiary.

         3.4 Granting of Options

         (a) The Committee shall from time to time, in its absolute discretion,
and subject to applicable limitations of this Plan:

         (i) Select from among the Employees or consultants (including Employees
or consultants who have previously received Options or other awards under this
Plan) such of them as in its opinion should be granted Options;

         (ii) Subject to the Award Limit, determine the number of shares to be
subject to such Options granted to the selected Employees or consultants;

         (iii) Determine whether such Options are to be Incentive Stock Options
or Non-Qualified Stock Options; and

         (iv) Determine the terms and conditions of such Options, consistent
with this Plan.

         (b) Upon the selection of an Employee or consultant to be granted an
Option, the Committee shall instruct the Secretary of the Company to issue the
Option and may impose such conditions on the grant of the Option as it deems
appropriate.

         (c) Any Incentive Stock Option granted under this Plan may be modified
by the Committee to disqualify such option from treatment as an "incentive stock
option" under Section 422 of the Code.

                                       6
<PAGE>   7
         (d) During the term of the Plan, (i) a person who is a Director as of
the Effective Date automatically shall be granted an option to purchase five
thousand (5,000) shares of Common Stock (subject to adjustment as provided in
Section 10.3) on the Effective Date and on the date of each annual meeting of
stockholders at which the Director is reelected to the Board or at which the
Director continues to serve, and (ii) a person who is initially elected or
appointed to the Board automatically shall be granted (A) an option to purchase
five thousand (5,000) shares of Common Stock (subject to adjustment as provided
in Section 10.3) on the date of such initial election or appointment and (B) an
option to purchase five thousand (5,000) shares of Common Stock (subject to
adjustment as provided in Section 10.3) on the date of each annual meeting of
stockholders occurring after such initial election or appointment at which the
Director is reelected to the Board or at which the Director continues to serve.
Members of the Board who are Employees of the Company who subsequently retire
from the Company and remain on the Board will not receive an initial Option
grant pursuant to clause (ii)(A) of the preceding sentence, but to the extent
that they are otherwise eligible, will receive, after retirement from the
Company, Options as described in the clause (ii)(B) of the preceding sentence.
All of the foregoing Option grants authorized by this Section 3.4(d) are subject
to stockholder approval of the Plan.

                                   ARTICLE IV

                                TERMS OF OPTIONS

         4.1 Option Agreement. Each Option shall be evidenced by a Stock Option
Agreement, which shall be executed by the Optionee and an authorized officer of
the Company and which shall contain such terms and conditions as the Committee
shall determine, consistent with this Plan.

         4.2 Option Price. The price per share of the shares subject to each
Option shall be set by the Committee; provided, however, that, except as
provided in Section 8.1 with respect to assumed options, such price shall not be
less than 100% of the Fair Market Value of a share of Common Stock on the date
the Option is granted.

         4.3 Option Term. The term of an Option shall be set by the Committee in
its discretion; provided, however, that (i) in the case of Options granted to
Directors, the term shall be ten (10) years from the date the Option is granted
and (ii) in the case of Incentive Stock Options, the term shall not be more than
ten (10) years from the date the Incentive Stock Option is granted, or five (5)
years from such date if the Incentive Stock Option is granted to an individual
then owning (within the meaning of Section 424(d) of the Code) more than 10% of
the total combined voting power of all classes of stock of the Company or any
Subsidiary).

                                       7
<PAGE>   8
         4.4  Option Vesting

         (a) The period during which the right to exercise an Option in whole or
in part vests in the Optionee shall be set by the Committee and the Committee
may determine that an Option may not be exercised in whole or in part for a
specified period after it is granted; provided, however, that, Options granted
to Directors shall become exercisable in cumulative annual installments of 25%
on each of the first, second, third and fourth annual meetings of the
stockholders following the date the Option is granted. At any time after grant
of an Option, the Committee may, in its sole and absolute discretion and subject
to whatever terms and conditions it selects, accelerate the period during which
an Option vests.

         (b) To the extent that the aggregate Fair Market Value of stock with
respect to which "incentive stock options" (within the meaning of Section 422 of
the Code, but without regard to Section 422(d) of the Code) are exercisable for
the first time by an Optionee during any calendar year (under the Plan and all
other incentive stock option plans of the Company and any parent or Subsidiary)
exceeds $100,000, such Options shall be treated as Non-Qualified Options to the
extent required by Section 422 of the Code. The rule set forth in the preceding
sentence shall be applied by taking Options into account in the order in which
they were granted. For purposes of this Section 4.4(b), the Fair Market Value of
stock shall be determined as of the time the Option with respect to such stock
is granted.

                                    ARTICLE V

                               EXERCISE OF OPTIONS

         5.1 Partial Exercise. An exercisable Option may be exercised in whole
or in part; however, an Option shall not be exercisable with respect to
fractional shares and the Committee may require that, by the terms of the
Option, a partial exercise be with respect to a minimum number of shares.

         5.2 Manner of Exercise. All or a portion of an exercisable Option shall
be deemed exercised upon delivery of all of the following to the Secretary of
the Company or his office:

         (a) A written notice complying with the applicable rules established by
the Committee stating that the Option, or a portion thereof, is exercised. The
notice shall be signed by the Optionee or other person then entitled to exercise
the Option or such portion;

         (b) Such representations and documents as the Committee, in its
absolute discretion, deems necessary or advisable to effect compliance with all
applicable provisions of the Securities Act of 1933, as amended, and any other
federal or state securities laws or regulations. The Committee or Board may, in
its absolute discretion, also take whatever additional actions it

                                       8
<PAGE>   9
deems appropriate to effect such compliance including, without limitation,
placing legends on share certificates and issuing stop-transfer notices to
agents and registrars;

         (c) In the event that the Option shall be exercised pursuant to Section
10.1 by any person or persons other than the Optionee, appropriate proof of the
right of such person or persons to exercise the Option; and

         (d) Full cash payment to the Secretary of the Company for the shares
with respect to which the Option, or portion thereof, is exercised. However, the
Committee may in its discretion or provide in the grant agreement (i) that
payment may be made, in whole or in part, through the delivery of shares of
Common Stock owned by the Optionee, duly endorsed for transfer to the Company,
with a Fair Market Value on the date of delivery not in excess of the aggregate
exercise price of the Option or exercised portion thereof and subject to such
other limitations as the Committee may impose thereon, (ii) allow payment, in
whole or in part, through the surrender of shares of Common Stock then issuable
upon exercise of the Option having a Fair Market Value on the date of Option
exercise equal to the aggregate exercise price of the Option or exercised
portion thereof, (iii) allow payment, in whole or in part, through the delivery
of property of any kind which constitutes good and valuable consideration; (iv)
allow payment, in whole or in part, through the delivery of a full recourse
promissory note bearing interest (at no less than such rate as shall then
preclude the imputation of interest under the Code) and payable upon such terms
as may be prescribed by the Committee, (v) allow payment through a
cashless-broker procedure approved by the Company, or (vi) allow payment through
any combination of the consideration provided above. In the case of a promissory
note, the Committee may also prescribe the form of such note and the security to
be given for such note. The Option may not be exercised, however, by delivery of
a promissory note or by a loan from the Company when or where such loan or other
extension of credit is prohibited by law.

         5.3 Conditions to Issuance of Stock Certificates. The Company shall not
be required to issue or deliver any certificate or certificates for shares of
stock purchased upon the exercise of any Option or portion thereof prior to
fulfillment of all of the following conditions:

         (a) The admission of such shares to listing on all stock exchanges on
which such class of stock is then listed;

         (b) The completion of any registration or other qualification of such
shares under any state or federal law, or under the rulings or regulations of
the Securities and Exchange Commission or any other governmental regulatory body
which the Committee shall, in its absolute discretion, deem necessary or
advisable;

         (c) The obtaining of any approval or other clearance from any state or
federal governmental agency which the Committee shall, in its absolute
discretion, determine to be necessary or advisable;

         (d) The lapse of such reasonable period of time following the exercise
of the Option as the Committee may establish from time to time for reasons of
administrative convenience; and

                                       9
<PAGE>   10
         (e) The receipt by the Company of full payment for such shares,
including payment of any applicable withholding tax.

         5.4 Rights as Stockholders. The holders of Options shall not be, nor
have any of the rights or privileges of, stockholders of the Company in respect
of any shares purchasable upon the exercise of any part of an Option unless and
until certificates representing such shares have been issued by the Company to
such holders.

         5.5 Ownership and Transfer Restrictions. The Committee, in its absolute
discretion, may impose such restrictions on the ownership and transferability of
the shares purchasable upon the exercise of an Option as it deems appropriate.
Any such restriction shall be set forth in the respective Stock Option Agreement
and may be referred to on the certificates evidencing such shares. The Committee
may require the Optionee to give the Company prompt notice of any disposition of
shares of Common Stock acquired by exercise of an Incentive Stock Option within
(i) two years from the date of granting such Option to such Optionee or (ii) one
year after the transfer of such shares to such Optionee. The Committee may
direct that the certificates evidencing shares acquired by exercise of an Option
refer to such requirement to give prompt notice of disposition.

         5.6 Limitations on Exercise of Options Granted to Directors. No Option
granted to a Director may be exercised to any extent by anyone after the first
to occur of the following events:

         (a) the expiration of twelve (12) months from the date of the
Optionee's death;

         (b) the expiration of twelve (12) months from the date of the
Optionee's ceasing to be a Director by reason of his permanent and total
disability (within the meaning of Section 22(e)(3) of the Code);

         (c) the expiration of three (3) months from the date of the Optionee's
ceasing to be a Director for any reason other than such Optionee's death or his
permanent and total disability, unless the Optionee dies within said three-month
period; or

         (d) the expiration of ten (10) years from the date the Option was
granted.

                                   ARTICLE VI

                            AWARD OF RESTRICTED STOCK

         6.1  Award of Restricted Stock

         (a)  The Committee shall from time to time, in its absolute discretion:

                                       10
<PAGE>   11
         (i) Select from among the Employees or consultants (including Employees
or consultants who have previously received other awards under this Plan) such
of them as in its opinion should be awarded Restricted Stock; and

         (ii) Determine the terms and conditions applicable to such Restricted
Stock, consistent with this Plan, which may include the achievement of
Performance Objectives.

         (b) Upon the selection of an Employee or consultant to be awarded
Restricted Stock, the Committee shall instruct the Secretary of the Company to
issue such Restricted Stock and may impose such conditions on the issuance of
such Restricted Stock as it deems appropriate.

         6.2 Restricted Stock Agreement. Restricted Stock shall be issued only
pursuant to a Restricted Stock Agreement, which shall be executed by the
selected Employee or consultant and an authorized officer of the Company and
which shall contain such terms and conditions as the Committee shall determine,
consistent with this Plan.

         6.3 Rights as Stockholders. Upon delivery of the shares of Restricted
Stock to the escrow holder, the Restricted Stockholder shall have, unless
otherwise provided by the Committee, all the rights of a stockholder with
respect to said shares, subject to the restrictions in his Restricted Stock
Agreement, including the right to receive all dividends and other distributions
paid or made with respect to the shares; provided, however, that in the
discretion of the Committee, any extraordinary distributions with respect to the
Common Stock shall be subject to the restrictions set forth in Section 6.4.

         6.4 Restriction. All shares of Restricted Stock issued under this Plan
(including any shares received by holders thereof with respect to shares of
Restricted Stock as a result of stock dividends, stock splits or any other form
of recapitalization) shall, in the terms of each individual Restricted Stock
Agreement, be subject to such restrictions as the Committee shall provide, which
restrictions may include, without limitation, restrictions concerning voting
rights and transferability and restrictions based on duration of employment with
the Company, Company performance and individual performance; provided, however,
that, by action taken after the Restricted Stock is issued, the Committee may,
on such terms and conditions as it may determine to be appropriate, remove any
or all of the restrictions imposed by the terms of the Restricted Stock
Agreement. Restricted Stock may not be sold or encumbered until all restrictions
are terminated or expire.

         6.5 Escrow. The Secretary of the Company or such other escrow holder as
the Committee may appoint shall retain physical custody of each certificate
representing Restricted Stock until all of the restrictions imposed under the
Restricted Stock Agreement with respect to the shares evidenced by such
certificate expire or shall have been removed.

         6.6 Legend. In order to enforce the restrictions imposed upon shares of
Restricted Stock hereunder, the Committee shall cause a legend or legends to be
placed on certificates representing all shares of Restricted Stock that are
still subject to restrictions under Restricted Stock

                                       11
<PAGE>   12
Agreements, which legend or legends shall make appropriate reference to the
conditions imposed thereby.

                                   ARTICLE VII

                    PERFORMANCE AWARDS, DIVIDEND EQUIVALENTS,
                         DEFERRED STOCK, STOCK PAYMENTS

         7.1 Performance Awards. Any Employee or consultant selected by the
Committee may be granted one or more Performance Awards. The value of such
Performance Awards may be linked to the achievement of such specific Performance
Objectives determined appropriate by the Committee over any period or periods
determined by the Committee. In making such determinations, the Committee shall
consider (among such other factors as it deems relevant in light of the specific
type of award) the contributions, responsibilities and other compensation of the
particular Employee or consultant.

         7.2 Dividend Equivalents. Any Employee or consultant selected by the
Committee may be granted Dividend Equivalents based on the dividends declared on
Common Stock, to be credited as of dividend payment dates, during the period
between the date an Option, Deferred Stock or Performance Award is granted, and
the date such Option, Deferred Stock or Performance Award is exercised, vests or
expires, as determined by the Committee. Such Dividend Equivalents shall be
converted to cash or additional shares of Common Stock by such formula and at
such time and subject to such limitations as may be determined by the Committee.

         7.3 Stock Payments. Any Employee or consultant selected by the
Committee may receive Stock Payments in the manner determined from time to time
by the Committee. The number of shares shall be determined by the Committee and
may be based upon the Fair Market Value, book value, net profits or other
measure of the value of Common Stock or other specific performance criteria
determined appropriate by the Committee, determined on the date such Stock
Payment is made or on any date thereafter.

         7.4 Deferred Stock. Any Employee or consultant selected by the
Committee may be granted an award of Deferred Stock in the manner determined
from time to time by the Committee. The number of shares of Deferred Stock shall
be determined by the Committee and may be linked to the achievement of such
specific Performance Objectives determined to be appropriate by the Committee
over any period or periods determined by the Committee. Common Stock underlying
a Deferred Stock award will not be issued until the Deferred Stock award has
vested, pursuant to a vesting schedule or Performance Objectives set by the
Committee, as the case may be. Unless otherwise provided by the Committee, a
Grantee of Deferred Stock shall have no rights as a Company stockholder with
respect to such Deferred Stock until such time as the award has vested and the
Common Stock underlying the award has been issued.

                                       12
<PAGE>   13
         7.5 Performance Award Agreement, Dividend Equivalent Agreement,
Deferred Stock Agreement, Stock Payment Agreement. Each Performance Award,
Dividend Equivalent, award of Deferred Stock and/or Stock Payment shall be
evidenced by an agreement, which shall be executed by the Grantee and an
authorized Officer of the Company and which shall contain such terms and
conditions as the Committee shall determine, consistent with this Plan.

         7.6 Term. The term of a Performance Award, Dividend Equivalent, award
of Deferred Stock and/or Stock Payment shall be set by the Committee in its
discretion.

         7.7 Exercise Upon Termination of Employment. A Performance Award,
Dividend Equivalent, award of Deferred Stock and/or Stock Payment is exercisable
or payable only while the Grantee is an Employee or consultant; provided that
the Committee may determine that the Performance Award, Dividend Equivalent,
award of Deferred Stock and/or Stock Payment may be exercised or paid subsequent
to termination of employment or termination of consultancy without cause, or
following a change in control of the Company, or because of the Grantee's
retirement, death or disability, or otherwise.

         7.8 Payment. Payment of the amount determined under Section 7.1 or 7.2
above shall be in cash, in Common Stock or a combination of both, as determined
by the Committee. To the extent any payment under this Article VII is effected
in Common Stock, it shall be made subject to satisfaction of all provisions of
Section 5.3.

                                  ARTICLE VIII

                         MERGED PLANS/REPLACEMENT AWARDS

         8.1 The following plans have been merged into this Plan: the Sooner,
Inc. 1998 Stock Option Plan and the HWC Energy Services, Inc. 1997 Stock Option
Plan, and all stock options and other stock-based awards granted under such
plans are converted into options and awards under this Plan with respect to
Common Stock. In addition, the individual stock option grants made outside of a
plan by Sooner, Inc. and PTI Group, Inc. to their respective employees and
outstanding on the date of their respective mergers with the Company or a
Company Subsidiary also are hereby assumed and converted into Company options.
The number of shares and the exercise price of each assumed award shall be made
pursuant to the applicable merger agreement between the Company and the
stockholders of such entities.

                                       13
<PAGE>   14
                                   ARTICLE IX

                                 ADMINISTRATION

         9.1 Committee. The Committee members shall be appointed by and hold
office at the pleasure of the Board. Appointment of Committee members shall be
effective upon acceptance of appointment. Committee members may resign at any
time by delivering written notice to the Board. Vacancies in the Committee may
be filled by the Board.

         9.2 Duties and Powers of Committee. It shall be the duty of the
Committee to conduct the general administration of this Plan in accordance with
its provisions. The Committee shall have the power to interpret this Plan and
the agreements pursuant to which Options, awards of Restricted Stock or Deferred
Stock, Performance Awards, Dividend Equivalents or Stock Payments are granted or
awarded, and to adopt such rules for the administration, interpretation, and
application of this Plan as are consistent therewith and to interpret, amend or
revoke any such rules. Any such grant or award under this Plan need not be the
same with respect to each Optionee, Grantee or Restricted Stockholder. Any such
interpretations and rules with respect to Incentive Stock Options shall be
consistent with the provisions of Section 422 of the Code. In its absolute
discretion, the Board may at any time and from time to time exercise any and all
rights and duties of the Committee under this Plan except with respect to
matters which under Rule 16b-3 or Section 162(m) of the Code, or any regulations
or rules issued thereunder, are required to be determined in the sole discretion
of the Committee.

         9.3 Majority Rule; Unanimous Written Consent. The Committee shall act
by a majority of its members in attendance at a meeting at which a quorum is
present or by a memorandum or other written instrument signed by all members of
the Committee.

         9.4 Compensation; Professional Assistance, Good Faith Actions. Members
of the Committee shall receive such compensation for their services as members
as may be determined by the Board. All expenses and liabilities which members of
the Committee incur in connection with the administration of this Plan shall be
borne by the Company. The Committee may employ attorneys, consultants,
accountants, appraisers, brokers, or other persons. The Committee, the Company
and the Company's officers and Directors shall be entitled to rely upon the
advice, opinions or valuations of any such persons. All actions taken and all
interpretations and determinations made by the Committee or the Board in good
faith shall be final and binding upon all Optionees, Grantees, Restricted
Stockholders, the Company and all other interested persons. No members of the
Committee or Board shall be personally liable for any action, determination or
interpretation made in good faith with respect to this Plan, Options, awards of
Restricted Stock or Deferred Stock, Performance Awards, Dividend Equivalents or
Stock Payments, and all members of the Committee and the Board shall be fully
protected by the Company in respect of any such action, determination or
interpretation.

                                       14
<PAGE>   15
                                    ARTICLE X

                            MISCELLANEOUS PROVISIONS

         10.1 Not Transferable. Except as provided below, Options, Restricted
Stock awards, Deferred Stock awards, Performance Awards, Dividend Equivalents or
Stock Payments under this Plan may not be sold, pledged, assigned, or
transferred in any manner other than by will or the laws of descent and
distribution or pursuant to a QDRO, unless and until such rights or awards have
been exercised, or the shares underlying such rights or awards have been issued,
and all restrictions applicable to such shares have lapsed. No Option,
Restricted Stock award, Deferred Stock award, Performance Award, Dividend
Equivalent or Stock Payment or interest or right therein shall be liable for the
debts, contracts or engagements of the Optionee, Grantee or Restricted
Stockholder or his successors in interest or shall be subject to disposition by
transfer, alienation, anticipation, pledge, encumbrance, assignment or any other
means whether such disposition be voluntary or involuntary or by operation of
law by judgment, levy, attachment, garnishment or any other legal or equitable
proceedings (including bankruptcy), and any attempted disposition thereof shall
be null and void and of no effect, except to the extent that such disposition is
permitted by the preceding sentence. An Optionee may, with the consent of the
Committee, transfer a Nonqualified Stock Option to such family members and
persons as may be permitted by this Committee, subject to such restrictions and
limitations, if any, that the Committee, in its discretion, may impose on such
transfer.

         During the lifetime of the Optionee or Grantee, only he may exercise an
Option or other right or award (or any portion thereof) granted to him under the
Plan unless it has been disposed of pursuant to a QDRO. After the death of the
Optionee or Grantee, any exercisable portion of an Option or other right or
award may, prior to the time when such portion becomes unexercisable under the
Plan or the applicable Stock Option Agreement or other agreement, be exercised
by his personal representative or by any person empowered to do so under the
deceased Optionee's or Grantee's will or under the then applicable laws of
descent and distribution.

         10.2 Amendment, Suspension or Termination of this Plan. This Plan may
be wholly or partially amended or otherwise modified, suspended or terminated at
any time or from time to time by the Board or the Committee. However, without
approval of the Company's stockholders given within twelve months before or
after the action by the Committee, no action of the Committee may, except as
provided in Section 10.3, increase the limits imposed in Section 2.1 on the
maximum number of shares which may be issued under this Plan or reduce the
exercise price of an Option, and no action of the Committee may be taken that
would otherwise require stockholder approval as a matter of applicable law,
regulation or rule. No amendment, suspension or termination of this Plan shall,
without the consent of the holder of Options, Restricted Stock awards, Deferred
Stock awards, Performance Awards, Dividend Equivalents or Stock Payments,
materially alter or impair any rights or obligations under any Options,
Restricted Stock awards, Deferred Stock awards, Performance Awards, Dividend
Equivalents or Stock Payments theretofore granted or awarded, unless the award
itself otherwise expressly so provides. No

                                       15
<PAGE>   16
Options, Restricted Stock, Deferred Stock, Performance Awards, Dividend
Equivalents or Stock Payments may be granted or awarded during any period of
suspension or after termination of this Plan, and in no event may any Incentive
Stock Option be granted under this Plan after the first to occur of the
following events:

         (a) The expiration of ten years from the date the Plan is adopted by
the Board; or

         (b) The expiration of ten years from the date the Plan is approved by
the Company's stockholders under Section 10.4.

         10.3 Changes in Common Stock or Assets of the Company; Acquisition or
Liquidation of the Company and Other Corporate Events.

         (a) Subject to Section 10.3(e), in the event that the Committee
determines that any dividend or other distribution (whether in the form of cash,
Common Stock, other securities, or other property), recapitalization,
reclassification, stock split, reverse stock split, reorganization, merger,
consolidation, split-up, spin-off, combination, repurchase, liquidation,
dissolution, or sale, transfer, exchange or other disposition of all or
substantially all of the assets of the Company, or exchange of Common Stock or
other securities of the Company, issuance of warrants or other rights to
purchase Common Stock or other securities of the Company, or other similar
corporate transaction or event, in the Committee's sole discretion, affects the
Common Stock such that an adjustment is determined by the, Committee to be
appropriate in order to prevent dilution or enlargement of the benefits or
potential benefits intended to be made available under the Plan or with respect
to an Option, Restricted Stock award, Performance Award, Dividend Equivalent,
Deferred Stock award or Stock Payment, then the Committee shall, in such manner
as it may deem equitable, adjust any or all of

         (i) the number and kind of shares of Common Stock (or other securities
or property) with respect to which Options, Performance Awards, Dividend
Equivalents or Stock Payments may be granted under the Plan, or which may be
granted as Restricted Stock or Deferred Stock (including, but not limited to,
adjustments of the limitations in Section 2.1 on the maximum number and kind of
shares which may be issued and adjustments of the Award Limit),

         (ii) the number and kind of shares of Common Stock (or other securities
or property) subject to outstanding Options, Performance Awards, Dividend
Equivalents, or Stock Payments, and in the number and kind of shares of
outstanding Restricted Stock or Deferred Stock, and

         (iii) the grant or exercise price with respect to any Option,
Performance Award, Dividend Equivalent or Stock Payment.

         (b) Subject to Section 10.3(e), in the event of any corporate
transaction or other event described in Section 10.3(a) which results in shares
of Common Stock being exchanged for or converted into cash, securities
(including securities of another corporation) or other property, the Committee
will have the right to terminate this Plan as of the date of the event or
transaction, in

                                       16
<PAGE>   17
which case all options, rights and other awards granted under this Plan shall
become the right to receive such cash, securities or other property, net of any
applicable exercise price.

         (c) Subject to Section 10.3(e), in the event of any corporate
transaction or other event described in Section 10.3(a) or any unusual or
nonrecurring transactions or events affecting the Company, any affiliate of the
Company, or the financial statements of the Company or any affiliate, or of
changes in applicable laws, regulations, or accounting principles, the Committee
in its discretion is hereby authorized to take any one or more of the following
actions whenever the Committee determines that such action is appropriate in
order to prevent dilution or enlargement of the benefits or potential benefits
intended to be made available under the Plan or with respect to any option,
right or other award under this Plan, to facilitate such transactions or events
or to give effect to such changes in laws, regulations or principles:

         (i) In its discretion, and on such terms and conditions as it deems
appropriate, the Committee may provide, either automatically or upon the
Optionee's request, for either the purchase of any such Option, Performance
Award, Dividend Equivalent, or Stock Payment, or any Restricted Stock or
Deferred Stock for an amount of cash equal to the amount that could have been
attained upon the exercise of such option, right or award or realization of the
Optionee's rights had such option, right or award been currently exercisable or
payable or the replacement of such option, right or award with other rights or
property selected by the Committee in its sole discretion;

         (ii) In its sole and absolute discretion, the Committee may provide,
either by the terms of such Option, Performance Award, Dividend Equivalent, or
Stock Payment, or Restricted Stock or Deferred Stock or by action taken prior to
the occurrence of such transaction or event that it cannot be exercised after
such event;

         (iii) In its sole and absolute discretion, and on such terms and
conditions as it deems appropriate, the Committee may provide, either by the
terms of such Option, Performance Award, Dividend Equivalent, or Stock Payment,
or Restricted Stock or Deferred Stock or by action taken prior to the occurrence
of such transaction or event, that, for a specified period of time prior to such
transaction or event, such option, right or award shall be exercisable as to all
shares covered thereby, notwithstanding anything to the contrary in (1) Section
4.4 or (2) the provisions of such Option, Performance Award, Dividend
Equivalent, or Stock Payment, or Restricted Stock or Deferred Stock;

         (iv) In its discretion, and on such terms and conditions as it deems
appropriate, the Committee may provide, either by the terms of such Option,
Performance Award, Dividend Equivalent, or Stock Payment, or Restricted Stock or
Deferred Stock or by action taken prior to the occurrence of such transaction or
event, that upon such event, such option, right or award be assumed by the
successor corporation, or a parent or subsidiary thereof, or shall be
substituted for by similar options, rights or awards covering the stock of the
successor corporation, or a parent or subsidiary thereof, with appropriate
adjustments as to the number and kind of shares and prices;

                                       17
<PAGE>   18
         (v) In its discretion, and on such terms and conditions as it deems
appropriate, the Committee may make adjustments in the number and type of shares
of Common Stock (or other securities or property) subject to outstanding
Options, Performance Awards, Dividend Equivalents, or Stock Payments, and in the
number and kind of outstanding Restricted Stock or Deferred Stock and/or in the
terms and conditions of (including the grant or exercise price), and the
criteria included in, outstanding options, rights and awards and options, rights
and awards which may be granted in the future;

         (vi) In its discretion, and on such terms and conditions as it deems
appropriate, the Committee may provide either by the terms of a Restricted Stock
award or Deferred Stock award or by action taken prior to the occurrence of such
event that, for a specified period of time prior to such event, the restrictions
imposed under a Restricted Stock Agreement or a Deferred Stock Agreement upon
some or all shares of Restricted Stock or Deferred Stock may be terminated; and

         (vii) In its discretion, and on such terms and conditions as it deems
appropriate, the Committee may make adjustments to the Performance Objectives of
any outstanding award.

         (d) Notwithstanding anything in Sections 10.3(a), 10.3(c) or 10.3(e) to
the contrary, except to the extent an award agreement expressly provides to the
contrary, in the event of a Change of Control of the Company all outstanding
awards automatically shall become fully vested immediately prior to such Change
in Control (or such earlier time as set by the Committee), all restrictions, if
any, with respect to such awards shall lapse, all performance criteria, if any,
with respect to such awards shall be deemed to have been met at their target
level.

         (e) With respect to an award intended to qualify as performance-based
compensation under Section 162(m), no adjustment or action described in this
Section 10.3, other than as provided in Section 10.3(d), shall be taken by the
Committee to the extent that such adjustment or action would cause such award to
fail to so qualify under Section 162(m) or any successor provisions thereto.

         10.4 Approval of Plan by Stockholders. This Plan will be submitted for
the approval of the Company's stockholders within twelve months after the date
of the Board's initial adoption of this Plan. Options, Performance Awards,
Dividend Equivalents or Stock Payments may be granted and Restricted Stock or
Deferred Stock may be awarded prior to such stockholder approval, provided that
such Options, Performance Awards, Dividend Equivalents or Stock Payments shall
not be exercisable and such Restricted Stock or Deferred Stock shall not vest
prior to the time when this Plan is approved by the stockholders, and provided
further that if such approval has not been obtained at the end of said
twelve-month period, all Options, Performance Awards, Dividend Equivalents or
Stock Payments previously granted and all Restricted Stock or Deferred Stock
previously awarded under this Plan, to the extent made with respect to shares in
excess of that number available for such awards immediately prior to this
amendment and restatement of the ConEmsco Plan, shall thereupon be canceled and
become null and void.

                                       18
<PAGE>   19
         10.5 Tax Withholding. The Company shall be entitled to require payment
in cash or deduction from other compensation payable to each Optionee, Grantee
or Restricted Stockholder of any sums required by applicable tax law to be
withheld with respect to the issuance, vesting or exercise of any Option,
Restricted Stock, Deferred Stock, Performance Award, Dividend Equivalent or
Stock Payment. Subject to the timing requirements of Section 5.3, the Committee
may, in its discretion and in satisfaction of the foregoing requirement, allow
such Optionee, Grantee or Restricted Stockholder to elect to have the Company
withhold shares of Common Stock otherwise issuable under such Option or
afterward (or allow the return of shares of Common Stock) having a Fair Market
Value equal to the minimum tax sums required to be withheld by the Company.
Notwithstanding the foregoing, any such person who is subject to Section 16b
with respect to Company Stock may direct that the Company's tax withholding
obligation be satisfied by withholding the appropriate number of shares from
such award and/or the "constructive" tender already-owned shares of Common
Stock.

         10.6 Loans. The Committee may, in its discretion, extend one or more
loans to Employees in connection with the exercise or receipt of an Option,
Performance Award, Dividend Equivalent or Stock Payment granted under this Plan,
or the issuance of Restricted Stock or Deferred Stock awarded under this Plan,
The terms and conditions of any such loan shall be set by the Committee.

         10.7 Limitations Applicable to Section 16 Persons and Performance-Based
Compensation. Notwithstanding any other provision of this Plan, this Plan, and
any Option, Performance Award, Dividend Equivalent or Stock Payment granted, or
Restricted Stock or Deferred Stock awarded, to any individual who is then
subject to Section 16 of the Exchange Act, shall be subject to any limitations
set forth in any applicable exemptive rule under Section 16 of the Exchange Act
(including any amendment to Rule 16b-3 of the Exchange Act) that are
requirements for the application of such exemptive rule. To the extent permitted
by applicable law, the Plan, Options, Performance Awards, Dividend Equivalents,
Stock Payments, Restricted Stock and Deferred Stock granted or awarded hereunder
shall be deemed amended to the extent necessary to conform to such applicable
exemptive rule. Furthermore, notwithstanding any other provision of this Plan,
any award intended to qualify as performance-based compensation as described in
Section 162(m)(4)(C) of the Code shall be subject to any additional limitations
set forth in Section 162(m) of the Code (including any amendment to Section
162(m) of the Code) or any regulations or rulings issued thereunder that are
requirements for qualification as performance-based compensation as described in
Section 162(m)(4)(C) of the Code.

         10.8 Effect of Plan Upon Options and Compensation Plans. Except as
provided in Section 8.1, this Plan amendment and restatement shall not affect
any other compensation or incentive plans in effect for the Company or any
Subsidiary. Nothing in this Plan shall be construed to limit the right of the
Company (i) to establish any other forms of incentives or compensation for
Employees, Directors or consultants of the Company or any Subsidiary or (ii) to
grant or assume options or other rights otherwise than under this Plan in
connection with any proper corporate purpose including but not by way of
limitation, the grant or assumption of

                                       19
<PAGE>   20
options in connection with the acquisition by purchase, lease, merger,
consolidation or otherwise, of the business, stock or assets of any corporation,
partnership, entity or association.

         10.9 Compliance with Laws. This Plan, the granting and vesting of
Options, Restricted Stock awards, Deferred Stock awards, Performance Awards,
Dividend Equivalents or Stock Payments under this Plan and the issuance and
delivery of shares of Common Stock and the payment of money under this Plan or
under Options, Performance Awards, Dividend Equivalents or Stock Payments
granted or Restricted Stock or Deferred Stock awarded hereunder are subject to
compliance with all applicable federal and state laws, rules and regulations
(including but not limited to state and federal securities law and federal
margin requirements) and to such approvals by any listing, regulatory or
governmental authority as may, in the opinion of counsel for the Company, be
necessary or advisable in connection therewith. Any securities delivered under
this Plan shall be subject to such restrictions, and the person acquiring such
securities shall, if requested by the Company, provide such assurances and
representations to the Company as the Company may deem necessary or desirable to
assure compliance with all applicable legal requirements. To the extent
permitted by applicable law, the Plan, Options, Restricted Stock awards,
Deferred Stock awards, Performance Awards, Dividend Equivalents or Stock
Payments granted or awarded hereunder shall be deemed amended to the extent
necessary to conform to such laws, rules and regulations.

         10.10 Titles. Titles are provided herein for convenience only and are
not to serve as a basis for interpretation or construction of this Plan.

         10.11 Governing Law. This Plan and any agreements hereunder shall be
administered, interpreted and enforced under the internal laws of the State of
Texas without regard to conflicts of laws thereof.

                                       20

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