EXHIBIT 99.99
                                                                   -------------

                             UNDERWRITING AGREEMENT


January 19, 2005

Advantage Energy Income Fund
Advantage Oil & Gas Ltd.
Advantage Investment Management Ltd.
3100, 150 - 6th Avenue SW
Calgary, Alberta T2P 3H7

Attention:    Peter A. Hanrahan, Vice President, Finance and Chief
              Financial Officer

Dear Sir:

Re:   Offering of Trust Units of Advantage Energy Income Fund

Scotia Capital Inc., BMO Nesbitt Burns Inc., National Bank Financial Inc., RBC
Dominion Securities Inc., CIBC World Markets Inc., FirstEnergy Capital Corp. and
Raymond James Ltd. (collectively, the "UNDERWRITERS") understand that Advantage
Energy Income Fund (the "TRUST") proposes to issue and sell 5,250,000 trust
units (the "OFFERED SECURITIES").

The Underwriters further understand that the Trust plans to use the net proceeds
from the offering of the Offered Securities to repay indebtedness which was
incurred in connection with the acquisition of Defiant Energy Corporation, for
the 2005 capital expenditures and for general purposes.

Subject to the terms and conditions hereof, the Underwriters hereby severally,
and not jointly, agree to purchase from the Trust the Offered Securities at the
Closing Time (as hereinafter defined) in the respective percentages set forth in
paragraph 19, and the Trust hereby agrees to issue and sell to the Underwriters
at the Closing Time all, but not less than all, of the Offered Securities at the
price of $21.65 for each of the Offered Securities for an aggregate purchase
price of $113,662,500.

1.       DEFINITIONS

In this agreement:

         (a)      "8.25% DEBENTURES" means the 8.25% convertible unsecured
                  subordinated debentures of the Trust;

         (b)      "9% DEBENTURES" means the 9.00% convertible unsecured
                  subordinated debentures of the Trust;

         (c)      "7.50% DEBENTURES" means the 7.50% convertible unsecured
                  subordinated debentures of the Trust;

         (d)      "7.75% DEBENTURES" means the 7.75% convertible unsecured
                  subordinated debentures of the Trust;

         (e)      "8.50% NOTES" means the 8.50% unsecured subordinated
                  promissory notes of Advantage Oil & Gas;

         (f)      "9 % NOTES" means the 9 % unsecured subordinated promissory
                  notes of Advantage Oil & Gas;


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         (g)      "10% DEBENTURES" means the 10.00% convertible unsecured
                  subordinated debentures of the Trust;

         (h)      "10 % NOTES" means the 10 % unsecured subordinated promissory
                  notes of Advantage Oil & Gas;

         (i)      "ABCA" means the BUSINESS CORPORATIONS ACT (Alberta), R.S.A.
                  2000, c. B-9, as amended, including the regulations
                  promulgated thereunder;

         (j)      "ADVANTAGE OIL & GAS" means Advantage Oil & Gas Ltd., a
                  corporation amalgamated pursuant to the ABCA;

         (k)      "AIF" means the revised annual information form of the Trust
                  dated May 12, 2004, including all schedules thereto;

         (l)      "ANADARKO" means Anadarko Canada Corporation;

         (m)      "ANADARKO'S AUDITORS" means KPMG LLP, chartered accountants,
                  Calgary, Alberta;

         (n)      "ANADARKO ENGINEERING REPORT" means the independent
                  engineering evaluations of Anadarko's oil, natural gas liquids
                  and natural gas interests in the Anadarko Properties prepared
                  by Sproule Associates Limited effective July 1, 2004;

         (o)      "ANADARKO FINANCIAL STATEMENTS" means the audited schedule of
                  revenues and operating expenses for the year ended December
                  31, 2003 with respect to the Anadarko Properties, together
                  with the notes thereto and auditors' report thereon and
                  interim unaudited schedule of revenues and expenses for the
                  six month periods ended June 30, 2004 and 2003 as contained in
                  the business acquisition report of the Trust dated September
                  30, 2004;

         (p)      "ANADARKO PROPERTIES" means the properties purchased by
                  Advantage Oil & Gas from Anadarko;

         (q)      "APPLICABLE SECURITIES LAWS" means all applicable Canadian
                  securities laws, rules, regulations, notices and policies in
                  the Qualifying Provinces and the corporate laws of Alberta;

         (r)      "ARRANGEMENT" means the plan of arrangement involving Defiant
                  Energy Corporation, its shareholders, Defiant Resources
                  Corporation, the Trust and Advantage Oil & Gas, which was
                  completed December21, 2004 under the provisions of the ABCA;

         (s)      "ASC" means the Alberta Securities Commission;

         (t)      "BUSINESS DAY" means a day which is not a Saturday or a Sunday
                  or a legal holiday in the City of Calgary, Alberta;

         (u)      "CLOSING DATE" means February 9, 2005 or such other date as
                  the Underwriters and the Trust may agree;

         (v)      "CLOSING TIME" means 6:15 a.m. (Calgary time) or such other
                  time, on the Closing Date, as the Underwriters and the Trust
                  may agree;


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         (w)      "DISTRIBUTION" means "DISTRIBUTION" or "DISTRIBUTION TO THE
                  PUBLIC", as the case may be, as defined under the Applicable
                  Securities Laws and "distribute" has a corresponding meaning;

         (x)      "DOCUMENTS" means, collectively, the documents incorporated by
                  reference in the Prospectuses and any Supplementary Material
                  including, without limitation:

                  (i)      the AIF,

                  (ii)     the audited comparative consolidated financial
                           statements of the Trust for the years ended December
                           31, 2003 and 2002, together with the notes thereto
                           and the auditor's report thereon,

                  (iii)    the information circular - proxy statement of the
                           Trust dated April 16, 2004 relating to the annual and
                           special meeting of holders of Trust Units held on May
                           26, 2004 (excluding those portions thereof which
                           appear under the headings "Performance Chart" and
                           "Corporate Governance"),

                  (iv)     the unaudited interim consolidated financial
                           statements of the Trust and management's discussion
                           and analysis of the financial condition and
                           operations of the Trust as at and for the three and
                           nine month periods ended September 30, 2004;

                  (v)      pages C-1 to C-11 of the short form prospectus of the
                           Trust dated September 3, 2004 consisting of the
                           unaudited financial statements of MarkWest for the
                           nine months ended September 30,2003, together with
                           the notes thereto;

                  (vi)     the business acquisition report of the Trust dated
                           September 30, 2004, including Schedules A and B
                           attached thereto, with respect to the acquisition by
                           the Trust of the Anadarko Properties;

                  (vii)    the material change report of the Trust dated
                           November 4, 2004 describing the Arrangement; and

                  (viii)   the material change report of the Trust dated
                           December 31, 2004 confirming the completion of the
                           Arrangement;

         (y)      "EXCHANGE" means the Toronto Stock Exchange;

         (z)      "EXCHANGEABLE SHARES" means exchangeable shares in the capital
                  of Advantage Oil & Gas, each such share being initially
                  exchangeable into one Trust Unit;

         (aa)     "MARKWEST" means MarkWest Resources Canada Corp.;

         (bb)     "MARKWEST AUDITOR'S" means PricewaterhouseCoopers LLP, the
                  former auditors of MarkWest;

         (cc)     "MANAGEMENT AGREEMENT" means the amended and restated
                  management agreement dated October 4, 2004 among Advantage Oil
                  & Gas, ManagementCo and the Trustee on behalf of the Trust;


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         (dd)     "MANAGEMENTCO" or the "MANAGER" means Advantage Investment
                  Management Ltd., a corporation incorporated under the ABCA;

         (ee)     "MATERIAL AGREEMENTS" means, collectively, the Trust
                  Indenture, Shareholder Agreement, Management Agreement, Note
                  Indentures and the Royalty Agreement;

         (ff)     "MISREPRESENTATION", "MATERIAL CHANGE" and "MATERIAL FACT"
                  shall have the meanings ascribed thereto under the Applicable
                  Securities Laws;

         (gg)     "MRRS PROCEDURES" means the mutual reliance review system and
                  procedures provided for by National Policy 43-201 of the
                  Canadian Securities Administrators relating to the Mutual
                  Reliance Review System;

         (hh)     "NI 44-101" means National Instrument 44-101 of the Canadian
                  Securities Administrators, as amended or replaced;

         (ii)     "NOTE INDENTURES" means the note indenture dated September 30,
                  2004 between Advantage Oil & Gas and Computershare Trust
                  Company of Canada providing for the issue of long term Notes
                  and the master note indenture dated September 30, 2004 between
                  Advantage Oil & Gas and Computershare Trust Company of Canada
                  providing for the issue of medium term Notes;

         (jj)     "NOTES" means the unsecured subordinated promissory notes of
                  Advantage Oil & Gas issued to the Trust from time to time
                  under the Note Indentures;

         (kk)     "PRELIMINARY PROSPECTUS" means the preliminary short form
                  prospectus of the Trust to be dated January 21, 2005 and any
                  amendments thereto, in respect of the distribution of the
                  Offered Securities, in the English and French languages,
                  including the documents incorporated by reference therein;

         (ll)     "PROSPECTUS" means the (final) short form prospectus of the
                  Trust and any amendments thereto, in respect of the
                  distribution of the Offered Securities, in the English and
                  French languages, including the documents incorporated by
                  reference therein;

         (mm)     "PROSPECTUS AMENDMENT" means any amendment to either the
                  Preliminary Prospectus or Prospectus, in the English and
                  French languages;

         (nn)     "PROSPECTUSES" means, collectively, the Preliminary Prospectus
                  and the Prospectus;

         (oo)     "PUBLIC RECORD" means all information filed after December 31,
                  2003 by or on behalf of the Trust and Advantage Oil & Gas with
                  the Securities Commissions, including without limitation, the
                  Documents, the Trust Financial Statements, the Prospectuses,
                  any Supplementary Material and any other information filed
                  with any Securities Commission in compliance, or intended
                  compliance, with any Applicable Securities Laws;

         (pp)     "QUALIFYING PROVINCES" means each of the provinces of Canada;

         (qq)     "ROYALTY" means the 95% interest in Advantage Oil & Gas'
                  Petroleum Substances (as defined in the Royalty Agreement)
                  within, upon or under certain of its Oil and Natural Gas
                  Properties (as defined in the Royalty Agreement) granted
                  pursuant to the Royalty Agreement;


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         (rr)     "ROYALTY AGREEMENT" means the amended and restated royalty
                  agreement entered into between Advantage Oil & Gas and the
                  Trust dated as of December 1, 2003 which provides for the
                  creation of the Royalty;

         (ss)     "SECURITIES COMMISSIONS" means the securities commissions or
                  similar regulatory authorities in the Qualifying Provinces;

         (tt)     "SELLING DEALER GROUP" means the dealers and brokers other
                  than the Underwriters who participate in the offer and sale of
                  the Offered Securities pursuant to this agreement;

         (uu)     "SHAREHOLDER AGREEMENT" means the shareholder agreement
                  entered into as of May 24, 2001 between Advantage Oil & Gas
                  and the Trustee, as trustee for and on behalf of the Trust;

         (vv)     "SPROULE" means Sproule Associates Limited, independent
                  petroleum consultants of Calgary, Alberta;

         (ww)     "SPROULE REPORT" means the independent engineering evaluation
                  of Advantage's oil, natural gas liquids and natural gas
                  interests prepared by Sproule dated April 19, 2004, and
                  effective December 31, 2003;

         (xx)     "SUBSIDIARY" has the meaning assigned thereto in the ABCA;

         (yy)     "Supplementary Material" means, collectively, any amendment to
                  the Preliminary Prospectus or Prospectus, any amended or
                  supplemented Preliminary Prospectus or Prospectus or any
                  ancillary material, information, evidence, return, report,
                  application, statement or document which may be filed by or on
                  behalf of the Trust under the Applicable Securities Laws;

         (zz)     "TAX ACT" means the INCOME TAX ACT (Canada) and the
                  regulations thereunder;

         (aaa)    "TRUST ASSETS" means, collectively, the Royalty, the Notes,
                  the Subsequent Investments, the Permitted Investments and
                  cash;

         (bbb)    "TRUST FINANCIAL STATEMENTS" means, collectively:

                  (i)      the audited comparative consolidated financial
                           statements of the Trust and management's discussion
                           and analysis of the financial condition and
                           operations of the Trust for the years ended December
                           31, 2003 and 2002 together with the notes thereto and
                           auditor's reports thereon, and

                  (ii)     the comparative interim unaudited consolidated
                           financial statements of the Trust and management's
                           discussion and analysis of the financial condition
                           and operations of the Trust for the nine months ended
                           September 30, 2004 and 2003;

         (ccc)    "TRUST INDENTURE" means the trust indenture dated as of April
                  17, 2001 as supplemented May 22, 2001 between the Trustee,
                  Advantage Oil & Gas and 687371 Alberta Ltd. as settlor as
                  amended and restated June 25, 2002, May 28, 2003 and May 26,
                  2004;

         (ddd)    "TRUST UNITS" means units of the Trust, each unit representing
                  an equal fractional undivided beneficial interest in the
                  Trust;


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         (eee)    "TRUST'S AUDITORS" means KPMG LLP, chartered accountants,
                  Calgary, Alberta;

         (fff)    "TRUST'S COUNSEL" means Burnet, Duckworth & Palmer LLP or such
                  other legal counsel as the Trust, with the consent of the
                  Underwriters, may appoint;

         (ggg)    "TRUSTEE" means Computershare Trust Company of Canada, as
                  trustee of the Trust; and

         (hhh)    "UNDERWRITERS' COUNSEL" means Macleod Dixon LLP or such other
                  legal counsel as the Underwriters, with the consent of the
                  Trust, may appoint.

Unless otherwise defined herein capitalized terms shall have the meanings
ascribed thereto in the AIF.

2.       UNDERWRITING FEE

In consideration for their services in underwriting the distribution of and
purchasing the Offered Securities, the Trust agrees to pay the Underwriters a
fee of $1.0825 for each of the Offered Securities purchased (being an aggregate
amount of $5,683,125), and all such fees shall be payable from the general funds
of the Trust. Such payment shall be made in accordance with paragraph 14 hereof.

The foregoing fees (the "UNDERWRITING FEE") may, at the sole option of the
Underwriters, be deducted from the aggregate gross proceeds of the sale of the
Offered Securities and withheld for the account of the Underwriters. For greater
certainty, the services provided by the Underwriters in connection herewith will
not be subject to the Goods and Services Tax provided for in the Excise Tax Act
(Canada) and taxable supplies provided will be incidental to the exempt
financial services provided. However, in the event that Canada Customs and
Revenue Agency determines that Goods and Services Tax provided for in the Excise
Tax Act (Canada) is exigible on the Underwriting Fee, the Trust agrees to pay
the amount of Goods and Services Tax forthwith upon the request of the
Underwriters. In the event that this offering is not completed, the Trust also
agrees to pay the Underwriters' reasonable expenses incurred in connection with
this underwriting as set forth in paragraph 11 hereof.

3.       QUALIFICATION FOR SALE

         (a)      The Trust represents and warrants to the Underwriters that it
                  is eligible to use the short form prospectus distribution
                  system described in NI 44-101 and the simplified prospectus
                  rules of the SECURITIES ACT (Quebec) for the distribution of
                  the Offered Securities.

         (b)      The Trust shall:

                  (i)      not later than 5:00 p.m. (Calgary time) on January
                           21, 2005, have prepared and filed the Preliminary
                           Prospectus (in the English and French languages) and
                           other documents required under the Applicable
                           Securities Laws with the Securities Commissions and
                           designated the ASC as the principal regulator;

                  (ii)     have obtained a preliminary MRRS decision document
                           from the ASC by 10:00 a.m. (Calgary time) on January
                           24, 2005 dated not later than January 21, 2005,
                           evidencing that a receipt has been issued for the
                           Preliminary Prospectus in each Qualifying Province;

                  (iii)    forthwith after any comments with respect to the
                           Preliminary Prospectus have been received from the
                           Securities Commissions have:


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                           (A)     prepared and filed not later than February 1,
                                   2005 (or such later date as may be agreed to
                                   in writing by the parties hereto) the
                                   Prospectus (in the English and French
                                   languages) and other documents required under
                                   the Applicable Securities Laws with the
                                   Securities Commissions; and

                           (B)     obtained a final MRRS decision document dated
                                   not later than February 1, 2005 from the ASC,
                                   evidencing that a receipt has been issued for
                                   the Prospectus in each Qualifying Province,
                                   or otherwise obtained a receipt for the
                                   Prospectus from each of the Securities
                                   Commissions;

                           and otherwise fulfilled all requirements of
                           Applicable Securities Laws to enable the Offered
                           Securities to be offered and sold to the public in
                           each of the Qualifying Provinces through the
                           Underwriters or any other investment dealer or broker
                           registered in the applicable Qualifying Province; and

                  (iv)     until the completion of the distribution of the
                           Offered Securities, promptly take all additional
                           steps and proceedings that from time to time may be
                           required under the Applicable Securities Laws in each
                           Qualifying Province to continue to qualify the
                           Offered Securities for distribution or, in the event
                           that the Offered Securities have, for any reason,
                           ceased to so qualify, to again qualify the Offered
                           Securities for distribution.

         (c)      Prior to the filing of the Prospectuses and, during the period
                  of distribution of the Offered Securities, prior to the filing
                  with any Securities Commissions of any Supplementary Material,
                  the Trust shall have allowed the Underwriters and the
                  Underwriters' counsel to participate fully in the preparation
                  of, and to approve the form of, such documents and to have
                  reviewed any documents incorporated by reference therein.

         (d)      During the period from the date hereof until completion of the
                  distribution of the Offered Securities, the Trust shall allow
                  the Underwriters to conduct all due diligence which they may
                  reasonably require in order to fulfil their obligations as
                  underwriters and in order to enable the Underwriters to
                  responsibly execute the certificates required to be executed
                  by them in the Prospectuses or in any Supplementary Material.

         (e)      During the period from the date hereof until completion of the
                  distribution of the Offered Securities, the Trust shall take
                  or cause to be taken all such other steps and proceedings,
                  including fulfilling all legal, regulatory and other
                  requirements, as required under Applicable Securities Laws to
                  qualify the Offered Securities for distribution to the public
                  in the Qualifying Provinces.

4.       DELIVERY OF PROSPECTUS AND RELATED DOCUMENTS

The Trust shall deliver or cause to be delivered without charge to the
Underwriters and the Underwriters' counsel the documents set out below at the
respective times indicated:

         (a)      Prior to or contemporaneously, as nearly as practicable, with
                  the filing with the Securities Commissions of each of the
                  Preliminary Prospectus and the Prospectus:

                  (i)      copies of the Preliminary Prospectus and the
                           Prospectus, each in the English and French languages,
                           signed as required by the Applicable Securities Laws
                           of the Qualifying Provinces; and


                                       8


                  (ii)     copies of any documents incorporated by reference
                           therein which have not previously been delivered to
                           the Underwriters;

                           as soon as they are available and in any event, not
                           later than one Business Day following the filing with
                           the Securities Commissions of the Preliminary
                           Prospectus or the Prospectus;

         (b)      As soon as they are available, copies of any Supplementary
                  Material, in the English and French languages, as required,
                  signed as required by the Applicable Securities Laws of the
                  Qualifying Provinces and including, in each case, copies of
                  any documents incorporated by reference therein which have not
                  been previously delivered to the Underwriters;

         (c)      Prior to the filing of the Prospectus with the Securities
                  Commissions, a "comfort letter" from each of the Trust's
                  auditors, MarkWest's auditors and Anadarko's auditors, dated
                  the date of the Prospectus, addressed to the Underwriters and
                  reasonably satisfactory in form and substance to the
                  Underwriters and the Underwriters' counsel, to the effect that
                  they have carried out certain procedures performed for the
                  purposes of comparing certain specified financial information
                  and percentages appearing in the Prospectus and the documents
                  incorporated therein by reference with indicated amounts in
                  the financial statements or accounting records of the Trust,
                  Advantage Oil & Gas, MarkWest or Anadarko, as applicable, and
                  have found such information and percentages to be in
                  agreement, which comfort letter shall be based on the
                  respective auditors review having a cut-off date of not more
                  than two Business Days prior to the date of the Prospectus;

         (d)      At the respective times of delivery to the Underwriters of the
                  Preliminary Prospectus and the Prospectus, the Trust shall
                  deliver to the Underwriters:

                  (i)      an opinion of local counsel in Quebec, addressed to
                           the Underwriters and the Underwriters' counsel and
                           dated at the date of the filing of the Preliminary
                           Prospectus and the Prospectus, respectively, in form
                           acceptable to the Underwriters and the Underwriters'
                           counsel, acting reasonably, to the effect that,
                           except for information in the Preliminary Prospectus
                           or Prospectus, as applicable, translated by the
                           Trust's auditors, MarkWest's auditors and Anadarko's
                           auditors the French language version of such document
                           (including information incorporated by reference
                           therein) is in all material respects a complete and
                           adequate translation of the English language versions
                           thereof and is not susceptible to any materially
                           different interpretation with respect to any material
                           matter contained therein; and

                  (ii)     a letter from each of the Trust's auditors,
                           MarkWest's auditors and Anadarko's auditors addressed
                           to the Underwriters and the Underwriters' counsel and
                           dated the date of the filing of the Preliminary
                           Prospectus and the Prospectus, respectively, in form
                           acceptable to the Underwriters and the Underwriters'
                           counsel, acting reasonably, to the effect that the
                           information excepted from the opinion of counsel
                           referred to in subparagraph (d)(i) in the French
                           language version of such document (including
                           information incorporated by reference therein) is in
                           all material respects a complete and proper
                           translation of the information contained in the
                           English language versions thereof.


                                       9


Opinions and comfort letters similar to the foregoing shall be provided to the
Underwriters with respect to any Supplementary Material and any other relevant
document at the time the same is presented to the Underwriters for their
signature or, if the Underwriters' signature is not required, at the time the
same is filed. All such letters shall be in form and substance reasonably
satisfactory to the Underwriters and the Underwriters' counsel.

Such deliveries shall also constitute the Trust's consent to the use by the
Underwriters and other members of the Selling Dealer Group of the Documents, the
Prospectuses and any Supplementary Material in connection with the offering and
sale of the Offered Securities in the Qualifying Provinces.

5.       COMMERCIAL COPIES

         (a)      The Trust shall, as soon as possible but in any event not
                  later than noon (local time at the place of delivery) on the
                  Business Day following the date of the filing of the
                  Preliminary Prospectus or the Prospectus, as the case may be,
                  and no later than noon (local time) on the first Business Day
                  after the execution of any Supplementary Material cause to be
                  delivered to the Underwriters, without charge, commercial
                  copies of the Preliminary Prospectus, the Prospectus or such
                  Supplementary Material (both English and French versions) in
                  such numbers and in such cities as the Underwriters may
                  reasonably request by oral or written instructions to the
                  Trust or the printer thereof given no later than the time when
                  the Trust authorizes the printing of the commercial copies of
                  such documents; and

         (b)      The Trust shall cause to be provided to the Underwriters such
                  number of copies of any documents incorporated by reference in
                  the Preliminary Prospectus, Prospectus or any Supplementary
                  Materials as the Underwriters may reasonably request.

6.       MATERIAL CHANGE

         (a)      During the period of distribution of the Offered Securities,
                  the Trust, Advantage Oil & Gas and ManagementCo will promptly
                  inform the Underwriters of the full particulars of:

                  (i)      any material change (actual, anticipated or
                           threatened) in or affecting the business, operations,
                           capital, condition (financial or otherwise) of the
                           Trust, Advantage Oil & Gas or their respective
                           properties, assets, liabilities (contingent or
                           otherwise), operations, revenue or subsidiaries, or
                           affecting the ability of ManagementCo to manage the
                           Trust and Advantage Oil & Gas;

                  (ii)     any change in any material fact contained or referred
                           to in the Preliminary Prospectus, the Prospectus or
                           any Supplementary Material; and

                  (iii)    the occurrence or discovery of a material fact or
                           event, which, in any such case, is, or may be, of
                           such a nature as to:

                           (A)     render the Preliminary Prospectus, Prospectus
                                   or any Supplementary Material untrue, false
                                   or misleading in a material respect;

                           (B)     result in a misrepresentation in the
                                   Preliminary Prospectus, the Prospectus or any
                                   Supplementary Material; or


                                       10


                           (C)     result in the Preliminary Prospectus, the
                                   Prospectus or any Supplementary Material not
                                   complying in any material respect with
                                   Applicable Securities Laws,

                  provided that if the Trust, Advantage Oil & Gas or
                  ManagementCo is uncertain as to whether a material change,
                  change, discovery, occurrence or event of the nature referred
                  to in this paragraph has occurred, the Trust, Advantage Oil &
                  Gas, or ManagementCo as the case may be, shall promptly inform
                  the Underwriters of the full particulars of the occurrence
                  giving rise to the uncertainty and shall consult with the
                  Underwriters as to whether the occurrence is of such nature;

         (b)      During the period of distribution of the Offered Securities,
                  the Trust, Advantage Oil & Gas and ManagementCo will promptly
                  inform the Underwriters of the full particulars of:

                  (i)      any request of any Securities Commission for any
                           amendment to the Preliminary Prospectus, the
                           Prospectus or any other part of the Public Record or
                           for any additional information;

                  (ii)     the issuance by any Securities Commission or similar
                           regulatory authority, the Exchange or by any other
                           competent authority of any order to cease or suspend
                           trading of any securities of the Trust or Advantage
                           Oil & Gas or of the institution or threat of
                           institution of any proceedings for that purpose; and

                  (iii)    the receipt by the Trust, Advantage Oil & Gas or
                           ManagementCo of any material communication from any
                           Securities Commission or similar regulatory
                           authority, the Exchange or any other competent
                           authority relating to the Preliminary Prospectus, the
                           Prospectus, any other part of the Public Record or
                           the distribution of the Offered Securities;

         (c)      The Trust, Advantage Oil & Gas and ManagementCo will promptly
                  comply to the reasonable satisfaction of the Underwriters and
                  the Underwriters' counsel with Applicable Securities Laws with
                  respect to any material change, change, occurrence or event of
                  the nature referred to in paragraphs 6(a) or (b) above and the
                  Trust, Advantage Oil & Gas and ManagementCo will prepare and
                  file promptly at the Underwriters' reasonable request any
                  amendment to the Preliminary Prospectus, the Prospectus or
                  Supplementary Material as may be required under Applicable
                  Securities Laws; provided that the Trust, Advantage Oil & Gas
                  and ManagementCo shall have allowed the Underwriters and the
                  Underwriters' counsel to participate fully in the preparation
                  of any Supplementary Material, to have reviewed any other
                  documents incorporated by reference therein and conduct all
                  due diligence investigations which the Underwriters may
                  reasonably require in order to fulfill their obligations as
                  underwriters and in order to enable the Underwriters
                  responsibly to execute the certificate required to be executed
                  by them in, or in connection with, any Supplementary Material,
                  such approval not to be unreasonably withheld and to be
                  provided in a timely manner. The Trust shall further promptly
                  deliver to each of the Underwriters and the Underwriters'
                  counsel a copy of each Supplementary Material in the English
                  and French languages as filed with the Securities Commissions,
                  and of opinions and letters with respect to each such
                  Supplementary Material substantially similar to those referred
                  to in paragraph 4 above; and


                                       11


         (d)      During the period of distribution of the Offered Securities,
                  the Trust will promptly provide to the Underwriters, for
                  review on a confidential basis by the Underwriters and the
                  Underwriters' counsel, prior to filing or issuance:

                  (i)      any financial statement of the Trust or Advantage Oil
                           & Gas;

                  (ii)     any proposed document, including without limitation
                           any amendment to the AIF, new annual information
                           form, material change report, interim report, or
                           information circular, which may be incorporated, or
                           deemed to be incorporated, by reference in the
                           Prospectus; and

                  (iii)    any press release of the Trust.

7.       REPRESENTATIONS AND WARRANTIES OF THE TRUST AND ADVANTAGE OIL & GAS

         (a)      Each delivery of the Preliminary Prospectus, the Prospectus
                  and any Prospectus Amendment pursuant to paragraph 4 above
                  shall constitute a joint and several representation and
                  warranty to the Underwriters by each of the Trust and
                  Advantage Oil & Gas (and each of the Trust and Advantage Oil &
                  Gas hereby acknowledges that each of the Underwriters is
                  relying on such representations and warranties in entering
                  into this agreement) that:

                  (i)      all of the information and statements (except
                           information and statements furnished by and relating
                           solely to the Underwriters) contained in the
                           Preliminary Prospectus, the Prospectus or any
                           Prospectus Amendment, as applicable, including,
                           without limitation, the documents incorporated by
                           reference, as the case may be:

                           (A)     are at the respective dates of such
                                   documents, true and correct in all material
                                   respects;

                           (B)     contain no misrepresentation; and

                           (C)     constitute full, true and plain disclosure of
                                   all material facts relating to the Trust,
                                   Advantage Oil & Gas, ManagementCo and the
                                   Offered Securities.

                  (ii)     the Preliminary Prospectus, the Prospectus and any
                           Prospectus Amendment, as applicable, including,
                           without limitation, the documents incorporated by
                           reference, as the case may be, complies in all
                           material respects with the Applicable Securities Laws
                           of the Qualifying Provinces, including without
                           limitation NI 44-101 and the simplified prospectus
                           rules of the Securities Act (Quebec); and

                  (iii)    except as is disclosed in the Public Record, there
                           has been no intervening material change (actual,
                           proposed or prospective, whether financial or
                           otherwise), from the date of the Preliminary
                           Prospectus, the Prospectus and any Prospectus
                           Amendment to the time of delivery thereof, in the
                           affairs, operations, assets, liabilities (contingent
                           or otherwise), or ownership of the Trust or Advantage
                           Oil & Gas, or to the extent (if any) to which it
                           affects the ability of the Manager to manage the
                           Trust, the Manager.

         (b)      In addition to the representations and warranties contained in
                  clause 7(a) hereof, each of the Trust and Advantage Oil & Gas
                  jointly and severally represents and warrants to the
                  Underwriters, and acknowledges that each of the Underwriters
                  is relying upon such representations and warranties in
                  entering into this agreement, that:

                  (i)      the Trust has been properly created and organized and
                           is a valid and subsisting trust under the laws of the
                           Province of Alberta and has all requisite trust
                           authority and power to carry on its activities as
                           described in the Prospectuses including, without
                           limitation, to perform its obligations under the
                           Material Agreements to which it is a party and to own
                           and administer its properties and assets including,
                           without limitation, the Trust Assets;

                  (ii)     each of Advantage Oil & Gas and ManagementCo has been
                           duly incorporated and organized and is valid and
                           subsisting in good standing under the laws of its
                           jurisdiction of incorporation, and has all requisite
                           corporate authority and power to carry on its
                           business as described in the Prospectuses and to own,
                           lease and operate its properties and assets as
                           described in the Prospectuses including, without
                           limitation, to perform its obligations under the
                           Material Agreements to which it is a party;

                  (iii)    each of Advantage Oil & Gas and ManagementCo is
                           qualified to carry on business and is validly
                           subsisting under the laws of each jurisdiction in
                           which it carries on a material portion of its
                           business and the Trust is qualified to carry on its
                           activities including, without limitation, owning the
                           Trust Assets in each jurisdiction where it carries on
                           such activities;


                                       12


                  (iv)     except for Advantage ExchangeCo Ltd. and other
                           non-material inactive subsidiaries and except as
                           described in the AIF neither the Trust nor Advantage
                           Oil & Gas has any subsidiaries (as defined in the
                           ABCA) and neither the Trust nor Advantage Oil & Gas
                           is "affiliated" with or a "holding corporation" of
                           any body corporate (within the meaning of those terms
                           in the ABCA);

                  (v)      the Trust is a "unit trust" and a "mutual fund trust"
                           under the Tax Act and the Trust shall at all times
                           conduct its affairs so as to continue to qualify as a
                           "unit trust" and a "mutual fund trust", including by
                           limiting its activities to investing the property of
                           the Trust in the Trust Assets and other property in
                           which a "mutual fund trust" is permitted by the Tax
                           Act to invest, and will not carry on any other
                           business;

                  (vi)     to the best of the knowledge of the Trust and
                           Advantage Oil & Gas, after reasonable inquiry,
                           non-residents of Canada (as that term is used in the
                           Tax Act) do not beneficially own more than 50% of the
                           issued and outstanding Trust Units;

                  (vii)    the authorized capital of Advantage Oil & Gas
                           consists of an unlimited number of common shares, an
                           unlimited number of non-voting common shares, an
                           unlimited number of preferred shares, issuable in
                           series and an unlimited number of Exchangeable Shares
                           of which 12,445,032 common shares are outstanding and
                           1,450,030 Exchangeable Shares are outstanding;


                                       13


                  (viii)   all of the issued and outstanding common shares in
                           the capital of Advantage Oil & Gas are fully paid and
                           non-assessable and legally and beneficially owned by
                           the Trust and, except for bank security, are free and
                           clear of all mortgages, liens, charges, pledges,
                           security interests, encumbrances, claims or demands
                           whatsoever and no person holds any securities
                           convertible into or exchangeable for issued or
                           unissued shares of Advantage Oil & Gas or has any
                           agreement, warrant, option, right or privilege
                           (whether pre-emptive or contractual) being or capable
                           of becoming an agreement, warrant, option or right
                           for the acquisition of any unissued or issued
                           securities of Advantage Oil & Gas;

                  (ix)     the Trust has full power and authority to issue the
                           Offered Securities;

                  (x)      upon receipt of the purchase price therefor, the
                           Offered Securities will be duly and validly issued as
                           fully paid and non-assessable Trust Units;

                  (xi)     none of the Trust, Advantage Oil & Gas and
                           ManagementCo is in default or breach of, and the
                           execution and delivery of, and the performance of and
                           compliance with the terms of this agreement by the
                           Trust, Advantage Oil & Gas and ManagementCo or any of
                           the transactions contemplated hereby does not and
                           will not result in any breach of, or constitute a
                           default under, and does not and will not create a
                           state of facts which, after notice or lapse of time
                           or both, would result in a breach of or constitute a
                           default under, the Trust Indenture, any term or
                           provision of the articles, by-laws or resolutions, as
                           applicable, of the Trust, Advantage Oil & Gas or
                           ManagementCo, or any indenture, mortgage, note,
                           contract, agreement (written or oral), instrument,
                           lease or other document including, without
                           limitation, any Material Agreement to which the
                           Trust, Advantage Oil & Gas or ManagementCo is a party
                           or by which any of the Trust, Advantage Oil & Gas or
                           ManagementCo is bound, or any judgment, decree,
                           order, statute, rule or regulation applicable to the
                           Trust, Advantage Oil & Gas or ManagementCo, which
                           default or breach might reasonably be expected to
                           materially adversely affect the business, operations,
                           capital, ownership or condition (financial or
                           otherwise) of the Trust and Advantage Oil & Gas (on a
                           consolidated basis) or their respective properties or
                           assets (taken as a whole);

                  (xii)    each of the Trust, Advantage Oil & Gas and
                           ManagementCo has full trust or corporate power and
                           authority to enter into this agreement and to perform
                           its obligations set out herein and this agreement has
                           been duly authorized, executed and delivered by the
                           Trust, Advantage Oil & Gas and ManagementCo and this
                           agreement is a legal, valid and binding obligation of
                           the Trust, Advantage Oil & Gas and ManagementCo
                           enforceable against the Trust, Advantage Oil & Gas
                           and ManagementCo in accordance with its terms subject
                           to the general qualifications set forth in the
                           opinion of the Trust's counsel to be delivered
                           pursuant to paragraph 13(a)(v);

                  (xiii)   there has not been any material change in the
                           capital, assets, liabilities or obligations
                           (absolute, accrued, contingent or otherwise) of the
                           Trust and Advantage Oil & Gas from the position set
                           forth in the Trust Financial Statements except as
                           contemplated by the Prospectuses and there has not
                           been any adverse material change in the business,
                           operations, capital or condition (financial or
                           otherwise) or results of the operations of the Trust
                           or Advantage Oil & Gas since December 31, 2003 except
                           as disclosed in the Prospectuses or the Public


                                       14


                           Record; and since that date there have been no
                           material facts, transactions, events or occurrences
                           which could materially adversely affect the capital,
                           assets, liabilities (absolute, accrued, contingent or
                           otherwise), business, operations or condition
                           (financial or otherwise) or results of the operations
                           of the Trust, Advantage Oil & Gas or ManagementCo (on
                           a consolidated basis) which have not been disclosed
                           in the Prospectuses or the Public Record;

                  (xiv)    the Trust Financial Statements fairly present, in
                           accordance with generally accepted accounting
                           principles in Canada, consistently applied, the
                           financial position and condition, the results of
                           operations, cash flows and the other information
                           purported to be shown therein of the Trust and
                           Advantage Oil & Gas as at the dates thereof and for
                           the periods then ended and reflect all assets,
                           liabilities and obligations (absolute, accrued,
                           contingent or otherwise) of the Trust and Advantage
                           Oil & Gas as at the dates thereof required to be
                           disclosed by generally accepted accounting principles
                           in Canada, and include all adjustments necessary for
                           a fair presentation;

                  (xv)     to the best of the knowledge of the Trust and
                           Advantage Oil & Gas, the Anadarko Financial
                           Statements fairly present, in all material respects,
                           in accordance with generally accepted accounting
                           principles in Canada, consistently applied, as they
                           apply to a statement of revenue and operating costs,
                           the revenues, royalties, operating costs, operating
                           income and other information purported to be shown
                           therein attributable to the Anadarko Properties as at
                           the dates thereof and for the periods then ended;

                  (xvi)    the pro forma financial statements, including the
                           notes thereto, of the Trust contained in the
                           Prospectuses have been prepared in accordance with
                           Canadian generally accepted accounting principles,
                           consistently applied, have been prepared and
                           presented in accordance with Applicable Securities
                           Laws, and include all adjustments necessary for a
                           fair presentation; the assumptions contained in such
                           pro forma financial statements are suitably supported
                           and consistent with the financial results of the
                           Trust, MarkWest, Advantage Oil & Gas and the Anadarko
                           Properties, and such statements provide a reasonable
                           basis for the compilation of the pro forma financial
                           statements and such pro forma financial statements,
                           accurately reflect such assumptions;

                  (xvii)   no authorization, approval or consent of any court or
                           governmental authority or agency is required to be
                           obtained by the Trust in connection with the sale and
                           delivery of the Offered Securities, except such as
                           may be required by the Exchange or under the
                           Applicable Securities Laws;

                  (xviii)  there are no actions, suits, proceedings or inquiries
                           existing or (as far as the Trust or Advantage Oil &
                           Gas are aware) pending or threatened against or
                           affecting the Trust, Advantage Oil & Gas or
                           ManagementCo at law or in equity or before or by any
                           federal, provincial, municipal or other governmental
                           department, commission, board, bureau, agency or
                           instrumentality which in any way materially adversely
                           affects, or may in any way materially adversely
                           affect, the business, operations or condition
                           (financial or otherwise) of the Trust, Advantage Oil
                           & Gas or ManagementCo (on a consolidated basis) or
                           their respective properties and assets or which
                           affects or may affect the distribution of the Offered
                           Securities;


                                       15


                  (xix)    each of the Trust, Advantage Oil & Gas and
                           ManagementCo has conducted and is conducting its
                           business in all material respects in compliance with
                           all applicable laws, rules and regulations of each
                           jurisdiction in which it carries on business and
                           holds all material licences, registrations and
                           qualifications in all jurisdictions in which it
                           carries on business necessary to carry on its
                           business as now conducted and as contemplated to be
                           conducted in the Prospectuses except where such
                           non-compliance or lack of license, registration or
                           qualification, in aggregate, would not have a
                           material adverse affect on the capital, assets,
                           liabilities (absolute, accrued, contingent or
                           otherwise), business, operations or condition
                           (financial or otherwise) or the results of the
                           operations of the Trust, Advantage Oil & Gas and
                           ManagementCo (on a consolidated basis);

                  (xx)     each of the Material Agreements is properly described
                           as to parties, dates and as to amendments thereto,
                           each of such agreements is a legal, valid and binding
                           obligation of the Trust, Advantage Oil & Gas and
                           ManagementCo, as the case may be, enforceable against
                           such parties in accordance with its terms subject to
                           the general qualifications set forth in the opinion
                           of the Trust's counsel to be delivered pursuant to
                           paragraph 13(a)(v) and each of the Trust, Advantage
                           Oil & Gas and ManagementCo, as applicable, are in
                           compliance with the terms of such Material Agreements
                           except where such non-compliance, in aggregate, would
                           not have a material adverse affect on the capital,
                           assets, liabilities (absolute accrued, contingent or
                           otherwise), business, operations or condition
                           (financial or otherwise) or the results of the
                           operations of the Trust, Advantage Oil & Gas or
                           ManagementCo (on a consolidated basis) and neither
                           the Trust or Advantage Oil & Gas is aware of any
                           default or breach of a material nature under any of
                           such Material Agreements by any other party thereto;

                  (xxi)    the information and statements set forth in the
                           Public Record to the extent incorporated by reference
                           in the Prospectuses were true, correct, and complete
                           and did not contain any misrepresentation, as of the
                           date of such information or statements;

                  (xxii)   the authorized capital of the Trust consists of an
                           unlimited number of Trust Units and an unlimited
                           number of Special Voting Units of which 50,457,474
                           Trust Units (which amount includes an aggregate of
                           763,373 Trust Units issued as partial payment of the
                           performance fee to the Manager and employees of
                           Advantage Oil & Gas on January 19, 2005 for services
                           rendered during the year ended December 31, 2004) and
                           one Special Voting Unit are issued and outstanding;

                  (xxiii)  except for the 10% Debentures, 9% Debentures, 8.25%
                           Debentures, 7.75% Debentures, 7.5% Debentures,
                           Exchangeable Shares and trust unit incentive rights
                           granted under the Trust Unit Rights Incentive Plan,
                           no person holds any securities convertible or
                           exchangeable into Trust Units or Special Voting Units
                           or has any agreement, warrant, option, right or
                           privilege being or capable of becoming an agreement,
                           warrant, option or right for the purchase of any
                           unissued Trust Units or Special Voting Units or other
                           securities of the Trust;

                  (xxiv)   no Securities Commission, the Exchange nor any
                           similar regulatory authority has issued any order
                           preventing or suspending trading in any securities of
                           the Trust and no proceedings, investigations or


                                       16


                           inquiries for such purpose are pending or
                           contemplated or (as far as the Trust or Advantage Oil
                           & Gas are aware) threatened;

                  (xxv)    Computershare Trust Company of Canada at its
                           principal offices in the cities of Calgary, Alberta
                           and Toronto, Ontario, is the duly appointed registrar
                           and transfer agent of the Trust with respect to the
                           Trust Units, the 10% Debentures, 9% Debentures, 8.25%
                           Debentures, 7.75% Debentures, 7.5% Debentures and
                           Exchangeable Shares;

                  (xxvi)   the minute books of the Trust, Advantage Oil & Gas
                           and ManagementCo contain true and correct copies of
                           the constating documents of the Trust, Advantage Oil
                           & Gas and ManagementCo and at the Closing Date will
                           contain true and correct copies or draft copies of
                           the minutes of all meetings and all resolutions of
                           the trustees and of the directors, shareholders and
                           unitholders of the Trust, Advantage Oil & Gas and
                           ManagementCo;

                  (xxvii)  other than as provided for in this agreement, neither
                           the Trust, Advantage Oil & Gas nor ManagementCo has
                           incurred any obligation or liability, contingent or
                           otherwise, for brokerage fees, finder's fees, agent's
                           commission or other similar forms of compensation
                           with respect to the transactions contemplated herein;

                  (xxviii) the issued and outstanding Trust Units are listed and
                           posted for trading on the Exchange and, absent any
                           circumstances that the Trust is not aware of at this
                           time, the Offered Securities will be listed and
                           posted for trading on the Exchange upon the Trust
                           complying with the usual conditions imposed by the
                           TSX with respect thereto;

                  (xxix)   the Trust is a "reporting issuer" in the provinces of
                           British Columbia, Alberta, Saskatchewan, Manitoba,
                           Ontario, Quebec, Newfoundland and Labrador, New
                           Brunswick and Nova Scotia, and within the meaning of
                           the Applicable Securities Laws in such provinces and
                           has the equivalent status in the province of Prince
                           Edward Island and is not in default of any material
                           requirement of Applicable Securities Laws;

                  (xxx)    the definitive form of certificate for the Trust
                           Units is in due and proper form under the laws
                           governing the Trust and in compliance with the
                           material requirements of the Exchange;

                  (xxxi)   Advantage Oil & Gas has made available to Sproule,
                           prior to the issuance of the Sproule Report, for the
                           purpose of preparing the Sproule Report, all
                           information requested by Sproule, which information
                           did not contain any material misrepresentation at the
                           time such information was provided. Except with
                           respect to changes in the prices of oil and gas,
                           neither the Trust nor Advantage Oil & Gas has any
                           knowledge of a material adverse change in any
                           production, cost, reserves or other relevant
                           information provided to Sproule since the date that
                           such information was so provided. Each of the Trust
                           and Advantage Oil & Gas believes that the Sproule
                           Report reasonably presents the quantity and pre-tax
                           present worth values of the oil and gas reserves
                           associated with the crude oil, natural gas liquids
                           and natural gas properties evaluated in such report
                           as at December 31, 2003 based upon information
                           available at the time such reserves information was
                           prepared, and the Trust and Advantage Oil & Gas


                                       17


                           believe that at the date of such report it did not
                           overstate the aggregate quantity or pre-tax present
                           worth values of such reserves or the estimated
                           monthly production volumes therefrom;

                  (xxxii)  to the best of the knowledge of the Trust and
                           Advantage Oil & Gas at the date of the Anadarko
                           Engineering Report such report did not overstate the
                           aggregate quantity or pre-tax present worth values of
                           such reserves or the estimated monthly production
                           volumes therefrom;

                  (xxxiii) neither the Trust nor Advantage Oil & Gas is aware of
                           any defects, failures or impairments in the title of
                           Advantage Oil & Gas to the crude oil, natural gas
                           liquids and natural gas properties, whether or not an
                           action, suit, proceeding or inquiry is pending or
                           threatened or whether or not discovered by any third
                           party, which in aggregate could have a material
                           adverse effect on: (A) the quantity and pre-tax
                           present worth values of crude oil, natural gas
                           liquids and natural gas reserves of Advantage Oil &
                           Gas; (B) the current production volumes of Advantage
                           Oil & Gas; or (C) the current cash flow of Advantage
                           Oil & Gas;

                  (xxxiv)  to the knowledge of the Trust and Advantage Oil &
                           Gas, the Trust has good and marketable title to the
                           Trust Assets, free and clear of all liens, charges,
                           encumbrances and security interests of any nature or
                           kind, except for bank security and as otherwise
                           described in the Prospectuses;

                  (xxxv)   except where such non-compliance or lack of obtaining
                           the items listed below would not have a material
                           adverse effect on the Trust (on a consolidated
                           basis), each of the Trust and Advantage Oil & Gas and
                           their subsidiaries have been and are in material
                           compliance with all applicable environmental
                           legislation, have obtained all material licences,
                           permits, approvals, consents, certificates,
                           registrations and other authorizations under
                           applicable environmental legislation necessary for
                           the operation of their projects as currently operated
                           and none of the Trust nor Advantage Oil & Gas nor
                           their subsidiaries (including, if applicable, any
                           predecessor companies thereof) have received any
                           notice of, or been prosecuted for, an offence
                           alleging material non-compliance with any
                           environmental legislation which remains outstanding
                           and which would have a material adverse effect on the
                           Trust (on a consolidated basis);

                  (xxxvi)  Advantage Oil & Gas has the necessary power and
                           authority to execute and deliver the Prospectuses on
                           behalf of the Trust and all requisite action has been
                           taken by Advantage Oil & Gas to authorize the
                           execution and delivery by it of the Prospectuses on
                           behalf of the Trust;

                  (xxxvii) the Trust is not an "Investment Company" within the
                           meaning of that term under the UNITED STATES
                           INVESTMENT COMPANY ACT of 1940;

                  (xxxviii) the attributes and characteristics of the Offered
                           Securities conform in all material respects to the
                           attributes and characteristics thereof described in
                           the Prospectuses;

                  (xxxix)  with such exceptions as are not material to the Trust
                           and Advantage Oil & Gas (taken as a whole), each of
                           the Trust and Advantage Oil & Gas has duly and on a
                           timely basis filed all tax returns required to be
                           filed by it, has paid all taxes due and payable by it


                                       18


                           and has paid all assessments and re-assessments and
                           all other taxes, governmental charges, penalties,
                           interest and other fines due and payable by it and
                           which were claimed by any governmental authority to
                           be due and owing and adequate provision has been made
                           for taxes payable for any completed fiscal period for
                           which tax returns are not yet required and there are
                           no agreements, waivers, or other arrangements
                           providing for an extension of time with respect to
                           the filing of any tax return or payment of any tax,
                           governmental charge or deficiency by the Trust or
                           Advantage Oil & Gas and to the best of the knowledge,
                           information and belief of the Trust and Advantage Oil
                           & Gas there are no actions, suits, proceedings,
                           investigations or claims threatened or pending
                           against the Trust or Advantage Oil & Gas in respect
                           of taxes, governmental charges or assessments or any
                           matters under discussion with any governmental
                           authority relating to taxes, governmental charges or
                           assessments asserted by any such authority; and

                  (xl)     the Trust has sufficient funds to pay to unitholders
                           of record on January 31, 2005 the distribution of
                           $0.28 per Trust Unit, such distribution to be paid on
                           February 15, 2005 and the Trust will have sufficient
                           funds to pay to unitholders of record on February 28,
                           2005 the cash distribution payable on each Trust
                           Unit, such distribution to be paid on March 15, 2005;

8.       REPRESENTATIONS AND WARRANTIES OF MANAGEMENTCO

ManagementCo represents and warrants to the Underwriters, and acknowledges that
each of the Underwriters is relying upon such representations and warranties in
entering into this agreement, that:

         (a)      ManagementCo has been duly incorporated and organized and is
                  valid and subsisting under the laws of the Province of
                  Alberta, and has all requisite corporate authority and power
                  to carry on its business as described in the Prospectuses and
                  to own, lease and operate its properties and assets as
                  described in the Prospectuses including, without limitation,
                  to perform its obligations under the Material Agreements to
                  which it is a party;

         (b)      ManagementCo is qualified to carry on business and is validly
                  subsisting under the laws of each jurisdiction in which it
                  carries on a material portion of its business;

         (c)      ManagementCo is not in default or breach of, and the execution
                  and delivery of, and the performance of and compliance with
                  the terms of this agreement by ManagementCo or any of the
                  transactions contemplated hereby does not and will not result
                  in any breach of, or constitute a default under, and does not
                  and will not create a state of facts which, after notice or
                  lapse of time or both, would result in a breach of or
                  constitute a default under, any term or provision of the
                  articles, by-laws or resolutions of ManagementCo, or any
                  indenture, mortgage, note, contract, agreement (written or
                  oral), instrument, lease or other document to which
                  ManagementCo is a party or by which ManagementCo is bound
                  including, without limitation, the Material Agreements to
                  which it is a party, or any judgment, decree, order, statute,
                  rule or regulation applicable to ManagementCo, which default
                  or breach might reasonably be expected to materially adversely
                  affect the business, operations, capital, ownership or
                  condition (financial or otherwise) of ManagementCo or its
                  properties or assets (taken as a whole);



                                       19


         (d)      ManagementCo has full corporate power and authority to enter
                  into this agreement and to perform its obligations set out
                  herein and this agreement has been duly authorized, executed
                  and delivered by ManagementCo and this agreement is a legal,
                  valid and binding obligation of ManagementCo enforceable
                  against ManagementCo in accordance with its terms subject to
                  the general qualifications set forth in the opinion of the
                  Trust's counsel to be delivered pursuant to paragraph
                  13(a)(v);

         (e)      there are no actions, suits, proceedings or inquiries pending
                  or (as far as ManagementCo is aware) threatened against or
                  affecting ManagementCo at law or in equity or before or by any
                  federal, provincial, municipal or other governmental
                  department, commission, board, bureau, agency or
                  instrumentality which in any way materially adversely affects,
                  or may in any way materially adversely affect, the business,
                  operations or condition (financial or otherwise) of
                  ManagementCo or its properties and assets (taken as a whole)
                  or its ability to manage the Trust;

         (f)      except where such non-compliance or lack of license,
                  registration or qualification, in aggregate, would not have a
                  material adverse affect on the business, operations or
                  condition (financial or otherwise) of ManagementCo or its
                  properties or assets (taken as a whole) or its ability to
                  manage the Trust, ManagementCo has conducted and is conducting
                  its business in all material respects in compliance with all
                  applicable laws, rules and regulations of each jurisdiction in
                  which it carries on business and holds all material licences,
                  registrations and qualifications in all jurisdictions in which
                  it carries on business necessary to carry on its business as
                  now conducted and as contemplated to be conducted in the
                  Prospectuses including, without limitation, performing its
                  obligations under the Material Agreements to which it is a
                  party;

         (g)      each of the Material Agreements to which ManagementCo is a
                  party is properly described as to parties, dates and as to
                  amendments thereto, each of such agreements is a legal, valid
                  and binding obligation of the respective parties thereto
                  enforceable against such parties in accordance with its terms
                  subject to the general qualifications set forth in the opinion
                  of the Trust's counsel to be delivered pursuant to paragraph
                  13(a)(v), ManagementCo is in compliance with the terms of such
                  Material Agreements to which it is a party except where such
                  non-compliance, in aggregate, would not have a material
                  adverse affect on the business, operations or conditions
                  (financial or otherwise) of ManagementCo or its properties or
                  assets (taken as a whole) or its ability to manage the Trust
                  and ManagementCo is not aware of any default or breach of a
                  material nature under any of such Material Agreements by any
                  other party thereto;

         (h)      the minute books of ManagementCo contain true and correct
                  copies of its constating documents and at the Closing Date
                  will contain true and correct copies or draft copies of the
                  minutes of all meetings and all resolutions of the directors
                  and shareholders of ManagementCo; and

         (i)      other than as provided for in this agreement, ManagementCo has
                  not incurred any obligation or liability, contingent or
                  otherwise, for brokerage fees, finder's fees, agent's
                  commission or other similar forms of compensation with respect
                  to the transactions contemplated herein.

9.       INDEMNITY

         (a)      The Trust and Advantage Oil & Gas, jointly and severally,
                  shall indemnify and save the Underwriters, and each of the
                  Underwriters' agents, directors, officers, shareholders and
                  employees harmless against and from all liabilities, claims,


                                       20


                  demands, losses (other than losses of profit in connection
                  with the distribution of the Offered Securities), costs
                  (including, without limitation, reasonable legal fees and
                  disbursements on a full indemnity basis), damages and expenses
                  to which the Underwriters, or any of the Underwriters' agents,
                  directors, officers, shareholders or employees may be subject
                  or which the Underwriters, or any of the Underwriters' agents,
                  directors, officers, shareholders or employees may suffer or
                  incur, whether under the provisions of any statute or
                  otherwise, in any way caused by, or arising directly or
                  indirectly from or in consequence of:

                  (i)      any information or statement contained in or
                           incorporated by reference into the Preliminary
                           Prospectus, the Prospectus, any Supplementary
                           Material or in any other document or material filed
                           or delivered pursuant hereto (other than any
                           information or statement relating solely to the
                           Underwriters and furnished to the Trust by the
                           Underwriters or the Underwriters' counsel expressly
                           for inclusion in the Preliminary Prospectus or
                           Prospectus) which is or is alleged to be untrue or
                           any omission or alleged omission to provide any
                           information or state any fact (other than any
                           information or fact relating solely to the
                           Underwriters) the omission of which makes or is
                           alleged to make any such information or statement
                           untrue or misleading in light of the circumstances in
                           which it was made;

                  (ii)     any misrepresentation or alleged misrepresentation
                           (except a misrepresentation which is based upon
                           information relating solely to the Underwriters and
                           furnished to the Trust by the Underwriters or the
                           Underwriters' counsel, as the case may be, expressly
                           for inclusion in the Preliminary Prospectus or
                           Prospectus) contained in or incorporated by reference
                           into the Preliminary Prospectus, the Prospectus, any
                           Supplementary Materials or in any other document or
                           any other part of the Public Record filed by or on
                           behalf of the Trust;

                  (iii)    any prohibition or restriction of trading in the
                           securities of the Trust or any prohibition or
                           restriction affecting the distribution of the Offered
                           Securities imposed by any competent authority (not
                           based on the activities or alleged activities of the
                           Underwriters or their banking or Selling Dealer Group
                           members, if any) if such prohibition or restriction
                           is based on any misrepresentation or alleged
                           misrepresentation of a kind referred to in
                           subparagraph 9(a)(ii);

                  (iv)     any order made or any inquiry, investigation (whether
                           formal or informal) or other proceeding commenced or
                           threatened by any one or more competent authorities
                           (not based upon the activities or the alleged
                           activities of the Underwriters or their banking or
                           Selling Dealer Group members, if any) prohibiting,
                           restricting, relating to or materially affecting the
                           trading or distribution of the Offered Securities; or

                  (v)      any breach of, default under or non-compliance by the
                           Trust, Advantage Oil & Gas or ManagementCo with any
                           requirements of Applicable Securities Laws, the
                           by-laws, rules or regulations of the Exchange or any
                           representation, warranty, term or condition of this
                           agreement or in any certificate or other document
                           delivered by or on behalf of the Trust, Advantage Oil
                           & Gas or ManagementCo hereunder or pursuant hereto;



                                       21


                  provided, however, no party who has engaged in any fraud,
                  wilful misconduct, fraudulent misrepresentation or negligence
                  shall be entitled, to the extent that the liabilities, claims,
                  losses, costs, damages or expenses were caused by such
                  activity, to claim indemnification from any person who has not
                  engaged in such fraud, wilful misconduct, fraudulent
                  misrepresentation or negligence (provided that, for greater
                  certainty, the foregoing shall not disentitle an Underwriter
                  from claiming indemnification hereunder to the extent that the
                  negligence, if any, relates to the Underwriter's failure to
                  conduct adequate "due diligence").

         (b)      If any claim contemplated by paragraph 10(a) shall be asserted
                  against any of the persons or corporations in respect of which
                  indemnification is or might reasonably be considered to be
                  provided for in such paragraphs, such person or corporation
                  (the "Indemnified Person") shall notify the Trust and
                  Advantage Oil & Gas as applicable (collectively the
                  "Indemnifying Parties") (provided that failure to so notify
                  the Indemnifying Parties of the nature of such claim in a
                  timely fashion shall relieve the Indemnifying Parties of
                  liability hereunder only if and to the extent that such
                  failure materially prejudices the Indemnifying Parties'
                  ability to defend such claim) as soon as possible of the
                  nature of such claim and the Indemnifying Parties shall be
                  entitled (but not required) to assume the defence of any suit
                  brought to enforce such claim, provided however, that the
                  defence shall be through legal counsel selected by the
                  Indemnifying Parties and acceptable to the Indemnified Person
                  acting reasonably and that no settlement or admission of
                  liability may be made by the Indemnifying Parties or the
                  Indemnified Person without the prior written consent of the
                  other, such consent not to be unreasonably withheld. The
                  Indemnified Person shall have the right to retain its own
                  counsel in any proceeding relating to a claim contemplated by
                  paragraph 10(a) if:

                  (i)      the Indemnified Person has been advised by counsel
                           that there may be a reasonable legal defense
                           available to the Indemnified Person which is
                           different from or additional to a defense available
                           to an Indemnifying Party and that representation of
                           the Indemnified Person and any one or more of the
                           Indemnifying Parties by the same counsel would be
                           inappropriate due to the actual or potential
                           differing interests between them (in which case the
                           Indemnifying Parties shall not have the right to
                           assume the defense of such proceedings on the
                           Indemnified Person's behalf);

                  (ii)     the Indemnifying Parties shall not have taken the
                           defense of such proceedings and employed counsel
                           within ten (10) days after notice has been given to
                           the Indemnifying Parties of commencement of such
                           proceedings; or

                  (iii)    the employment of such counsel has been authorized by
                           the Indemnifying Parties in connection with the
                           defense of such proceedings; and, in any such event,
                           the reasonable fees and expenses of such Indemnified
                           Person's counsel (on a solicitor and his client
                           basis) shall be paid by the Indemnifying Parties,
                           provided that the Indemnifying Parties shall not, in
                           connection with any one such action or separate but
                           substantially similar or related actions in the same
                           jurisdiction arising out of the same general
                           allegations or circumstances, be liable for the fees
                           and expenses of more than one separate law firm (in
                           addition to any local counsel) for all such
                           Indemnified Persons.

         (c)      Each of the Indemnifying Parties hereby waives its rights to
                  recover contribution from the Underwriters with respect to any
                  liability of the Indemnifying Party by reason of or arising
                  out of any misrepresentation in the Preliminary Prospectus,
                  the Prospectus, any Supplementary Material or any other part


                                       22


                  of the Public Record provided, however, that such waiver shall
                  not apply in respect of liability caused or incurred by reason
                  of any misrepresentation which is based upon information
                  relating solely to the Underwriters contained in such document
                  and furnished to the Trust by the Underwriters expressly for
                  inclusion in the Preliminary Prospectus or the Prospectus.

         (d)      If any legal proceedings shall be instituted against an
                  Indemnifying Party in respect of the Preliminary Prospectus,
                  the Prospectus, any Supplementary Material or any other part
                  of the Public Record, or if any regulatory authority or stock
                  exchange shall carry out an investigation of an Indemnifying
                  Party in respect of the Preliminary Prospectus, the
                  Prospectus, any Supplementary Material or any other part of
                  the Public Record, and, in either case, any Indemnified Person
                  is required to testify, or respond to procedures designed to
                  discover information, in connection with or by reason of the
                  services performed by the Underwriters hereunder, the
                  Indemnified Persons may employ their own legal counsel and the
                  Indemnifying Parties shall pay and reimburse the Indemnified
                  Persons for the reasonable fees, charges and disbursements (on
                  a full indemnity basis) of such legal counsel, the other
                  expenses reasonably incurred by the Indemnified Persons in
                  connection with such proceedings or investigation and a fee at
                  the normal per diem rate for any director, officer or employee
                  of the Underwriters involved in the preparation for or
                  attendance at such proceedings or investigation.

         (e)      The rights and remedies of the Indemnified Persons set forth
                  in paragraphs 9, 10 and 11 hereof are to the fullest extent
                  possible in law cumulative and not alternative and the
                  election by any Underwriter or other Indemnified Person to
                  exercise any such right or remedy shall not be, and shall not
                  be deemed to be, a waiver of any other rights and remedies.

         (f)      The Indemnifying Parties hereby acknowledge that the
                  Underwriters are acting as agents for the Underwriters'
                  respective agents, directors, officers, shareholders and
                  employees under this paragraph 9 and under paragraph 10 with
                  respect to all such agents, directors, officers, shareholders
                  and employees.

         (g)      The Indemnifying Parties waive any right they may have of
                  first requiring an Indemnified Person to proceed against or
                  enforce any other right, power, remedy or security or claim or
                  to claim payment from any other person before claiming under
                  this indemnity. It is not necessary for an Indemnified Person
                  to incur expense or make payment before enforcing such
                  indemnity.

         (h)      The rights of indemnity contained in this paragraph 9 shall
                  not apply if the Indemnifying Parties have complied with the
                  provisions of paragraphs 3 and 4 and the person asserting any
                  claim contemplated by this paragraph 9 was not provided with a
                  copy of the Prospectus or any amendment to the Prospectus or
                  other document which corrects any misrepresentation or alleged
                  misrepresentation which is the basis of such claim and which
                  was required, under Applicable Securities Laws, to be
                  delivered to such person by the Underwriters.

         (i)      If the Indemnifying Parties have assumed the defense of any
                  suit brought to enforce a claim hereunder, the Indemnified
                  Person shall provide the Indemnifying Parties copies of all
                  documents and information in its possession pertaining to the
                  claim, take all reasonable actions necessary to preserve its
                  rights to object to or defend against the claim, consult and
                  reasonably cooperate with the Indemnifying Parties in
                  determining whether the claim and any legal proceeding


                                       23


                  resulting therefrom should be resisted, compromised or settled
                  and reasonably cooperate and assist in any negotiations to
                  compromise or settle, or in any defense of, a claim undertaken
                  by the Indemnifying Parties.

10.      CONTRIBUTION

In order to provide for just and equitable contribution in circumstances in
which the indemnification provided for in this agreement is due in accordance
with its terms but is, for any reason, held by a court to be unavailable from
one or more of the Indemnifying Parties on grounds of policy or otherwise, the
Indemnifying Parties and the party or parties seeking indemnification shall
contribute to the aggregate liabilities, claims, demands, losses (other than
losses of profit in connection with the distribution of the Offered Securities),
costs (including, without limitation, reasonable legal fees and disbursements on
a full indemnity basis), damages and expenses to which they may be subject or
which they may suffer or incur:

         (a)      in such proportion as is appropriate to reflect the relative
                  benefit received by the Indemnifying Parties on the one hand,
                  and by the Underwriters on the other hand, from the offering
                  of the Offered Securities; or

         (b)      if the allocation provided by paragraph 10(a) above is not
                  permitted by applicable law, in such proportion as is
                  appropriate to reflect not only the relative benefits referred
                  to in paragraph 10(a) above but also to reflect the relative
                  fault of the Underwriters on the one hand, and the
                  Indemnifying Parties, on the other hand, in connection with
                  the statements, commissions or omissions or other matters
                  which resulted in such liabilities, claims, demands, losses,
                  costs, damages or expenses, as well as any other relevant
                  equitable considerations.

The relative benefits received by the Indemnifying Parties, on the one hand, and
the Underwriters, on the other hand, shall be deemed to be in the same
proportion that the total proceeds of the offering received by the Indemnifying
Parties (net of fees but before deducting expenses) bear to the fees received by
the Underwriters. In the case of liability arising out of the Preliminary
Prospectus, the Prospectus, any Supplementary Material or any other part of the
Public Record, the relative fault of the Indemnifying Parties, on the one hand,
and of the Underwriters, on the other hand, shall be determined by reference,
among other things, to whether the misrepresentation or alleged
misrepresentation, order, inquiry, investigation or other matter or thing
referred to in paragraph 9 relates to information supplied or which ought to
have been supplied by, or steps or actions taken or done on behalf of or which
ought to have been taken or done on behalf of, one or more of the Indemnifying
Parties or the Underwriters and the parties' relative intent, knowledge, access
to information and opportunity to correct or prevent such misrepresentation or
alleged misrepresentation, order, inquiry, investigation or other matter or
thing referred to in paragraph 9.

The amount paid or payable by an Indemnified Person as a result of liabilities,
claims, demands, losses (other than losses of profit in connection with the
distribution of the Offered Securities), costs, damages and expenses (or claims,
actions, suits or proceedings in respect thereof) referred to above shall,
without limitation, include any legal or other expenses reasonably incurred by
the Indemnified Person in connection with investigating or defending such
liabilities, claims, demands, losses, costs, damages and expenses (or claims,
actions, suits or proceedings in respect thereof) whether or not resulting in
any action, suit, proceeding or claim.

Each of the Indemnifying Parties and the Underwriters agree that it would not be
just and equitable if contributions pursuant to this agreement were determined
by pro rata allocation or by any other method of allocation which does not take
into account the equitable considerations referred to in the immediately
preceding paragraphs. The rights to contribution provided in this paragraph 10
shall be in addition to, and without prejudice to, any other right to
contribution which the Underwriters or other Indemnified Persons may have.


                                       24


Any liability of the Underwriters under this paragraph 10 shall be limited to
the amount actually received by the Underwriters under paragraph 2.

11.      EXPENSES

Whether or not the transactions contemplated herein shall be completed, all
costs and expenses (including applicable goods and services tax) of or
incidental to the transactions contemplated hereby including, without
limitation, those relating to the distribution of the Offered Securities shall
be borne by the Trust including, without limitation, all costs and expenses of
or incidental to the preparation, filing, reproduction (including the commercial
copies thereof) and translation of the Preliminary Prospectus, the Prospectus
and any Supplementary Material and the delivery thereof to the Underwriters, the
fees and expenses of the Trust's counsel, the fees and expenses of agent counsel
retained by the Trust or the Trust's counsel, the fees and expenses of the
Trust's transfer agent, auditors, engineers and other outside consultants, all
stock exchange listing fees, the cost of preparing record books for all of the
parties to this agreement and their respective counsel, any newspaper
advertisements on behalf of the Trust and all other reasonable costs and
expenses relating to this transaction. In the event that the offering of the
Offered Securities is not completed, the Trust will pay the reasonable fees and
expenses of the Underwriters' counsel and all other reasonable out-of-pocket
expenses incurred by the Underwriters.

12.      TERMINATION

         (a)      The Underwriters, or any of them, may, without liability,
                  terminate their obligations hereunder, by written notice to
                  the Trust in the event that after the date hereof and at or
                  prior to the Closing Time:

                  (i)      any order to cease or suspend trading in any
                           securities of the Trust or Advantage Oil & Gas or
                           prohibiting or restricting the distribution of any of
                           the Offered Securities is made, or proceedings are
                           announced, commenced or threatened for the making of
                           any such order, by any securities commission or
                           similar regulatory authority, the Exchange or by any
                           other competent authority, and has not been
                           rescinded, revoked or withdrawn;

                  (ii)     any inquiry, investigation (whether formal or
                           informal) or other proceeding in relation to the
                           Trust, Advantage Oil & Gas, ManagementCo or any of
                           the directors or senior officers of Advantage Oil &
                           Gas or ManagementCo is announced, commenced or
                           threatened by any securities commission or similar
                           regulatory authority, the Exchange or by any other
                           competent authority or there is a change in law,
                           regulation or policy or the interpretation or
                           administration thereof, if, in the reasonable opinion
                           of the Underwriters or any one of them, the change,
                           announcement, commencement or threatening thereof
                           adversely affects the trading or distribution of the
                           Offered Securities or any other securities of the
                           Trust;

                  (iii)    there shall have occurred any adverse change, as
                           determined by the Underwriters or any one of them in
                           their sole discretion, acting reasonably, in the
                           business, operations, capital or condition (financial
                           or otherwise), business or business prospects of the
                           Trust, Advantage Oil & Gas, ManagementCo (taken as a
                           whole) or the respective properties, assets,
                           liabilities or obligations (absolute, accrued,


                                       25


                           contingent or otherwise) of the Trust, Advantage Oil
                           & Gas, ManagementCo (taken as a whole) which in the
                           Underwriters' opinion, could reasonably be expected
                           to have a significant adverse effect on the market
                           price or value of the Offered Securities or any other
                           securities of the Trust or the investment quality or
                           marketability of the Offered Securities or any other
                           securities of the Trust;

                  (iv)     there should develop, occur or come into effect or
                           existence any event, action, state, condition or
                           major financial occurrence of national or
                           international consequence or any law, action or
                           regulation or other occurrence of any nature
                           whatsoever which, in the sole opinion of the
                           Underwriters or any one of them, acting reasonably,
                           seriously adversely affects, or involves, or will
                           seriously adversely affect, or involve, the financial
                           markets or the business, operations or affairs of the
                           Trust, Advantage Oil & Gas and ManagementCo (taken as
                           a whole), such that it would not be practical (in the
                           sole opinion of the Underwriters, or any one of them,
                           acting reasonably) to market the Offered Securities
                           or any other securities of the Trust;

                  (v)      the Underwriters shall become aware of any material
                           fact (including an adverse material change) with
                           respect to the Trust, Advantage Oil & Gas or
                           ManagementCo which had not been publicly disclosed or
                           disclosed in writing to the Underwriters at or prior
                           to the date hereof which, in the sole opinion of the
                           Underwriters or any one of them, could reasonably be
                           expected to have a significant adverse effect on the
                           market price or value of the Offered Securities or
                           any other securities of the Trust or the investment
                           quality or marketability of the Offered Securities or
                           any other securities of the Trust;

                  (vi)     the Trust, Advantage Oil & Gas or ManagementCo shall
                           be in breach or default under or non-compliance with
                           any representation, warranty, term or condition of
                           this agreement, in any material respect; or

                  (vii)    there is announced any change or proposed change in
                           the income tax laws of Canada or the interpretation
                           or administration thereof and such change, which in
                           the sole opinion of the Underwriters, or any one of
                           them, could reasonably be expected to have a
                           significant adverse effect on the market price or
                           value of the Offered Securities or any other
                           securities of the Trust.

         (b)      The Underwriters, or any of them, may exercise any or all of
                  the rights provided for in paragraph 12(a) or paragraph 18
                  notwithstanding any material change, change, event or state of
                  facts and (except where the Underwriter purporting to exercise
                  any of such rights is in breach of its obligations under this
                  agreement) notwithstanding any act or thing taken or done by
                  the Underwriters or any inaction by the Underwriters, whether
                  before or after the occurrence of any material change, change,
                  event or state of facts including, without limitation, any act
                  of the Underwriters related to the offering or continued
                  offering of the Offered Securities for sale and any act taken
                  by the Underwriters in connection with any amendment to the
                  Prospectus (including the execution of any amendment or any
                  other Supplementary Material) and the Underwriters shall only
                  be considered to have waived or be estopped from exercising or
                  relying upon any of their rights under or pursuant to
                  paragraph 12(a) or paragraph 18 if such waiver or estoppel is
                  in writing and specifically waives or estops such exercise or
                  reliance.


                                       26


         (c)      Any termination pursuant to the terms of this agreement shall
                  be effected by notice in writing delivered to the Trust,
                  provided that no termination shall discharge or otherwise
                  affect any obligation of the Trust, Advantage Oil & Gas under
                  paragraphs 9, 10, or 18. The rights of the Underwriters to
                  terminate their obligations hereunder are in addition to, and
                  without prejudice to, any other remedies they may have.

         (d)      If an Underwriter elects to terminate its obligation to
                  purchase the Offered Securities as aforesaid, whether the
                  reason for such termination is within or beyond the control of
                  the Trust, Advantage Oil & Gas or ManagementCo, the liability
                  of the Trust, Advantage Oil & Gas or ManagementCo hereunder
                  shall be limited to the indemnity referred to in paragraph 9,
                  the contribution rights referred to in paragraph 10 and the
                  payment of expenses referred to in paragraph 11; provided,
                  however, an Underwriter shall not be entitled to the payment
                  of expenses referred to in paragraph 11 if an Underwriter is
                  in breach of or default under or non-compliance with any
                  representation, warranty, term or condition of this Agreement,
                  in any material respect.

13.      CLOSING DOCUMENTS

The obligations of the Underwriters hereunder, as to the Offered Securities to
be purchased at the Closing Time shall be conditional upon the Trust, Advantage
Oil & Gas and ManagementCo having performed in all material respects, at the
Closing Time, all of their obligations hereunder theretofore to be performed and
the Underwriters receiving at the Closing Time:

         (a)      favorable legal opinions of the Trust's counsel and the
                  Underwriters' counsel addressed to the Underwriters, in form
                  and substance reasonably satisfactory to the Underwriters,
                  with respect to such matters as the Underwriters may
                  reasonably request relating to the offering of the Offered
                  Securities, the Trust, Advantage Oil & Gas and ManagementCo
                  and the transactions contemplated hereby, including, without
                  limitation, that:

                  (i)      the Trust is valid and existing as a trust under the
                           laws of the Province of Alberta and having the
                           Trustee as its trustee;

                  (ii)     the Trust has the capacity and power to own and lease
                           its properties and assets and to conduct its business
                           as described in the Prospectuses;

                  (iii)    each of Advantage Oil & Gas and ManagementCo has been
                           duly incorporated, is validly subsisting and has all
                           requisite corporate power and authority to carry on
                           its business as now conducted by it and to own its
                           properties and assets and is qualified to carry on
                           business under the laws of the jurisdictions where it
                           carries on a material portion of its business;

                  (iv)     the Trust is the registered holder of all issued and
                           outstanding common shares and Notes of Advantage Oil
                           & Gas, all of which common shares have been duly
                           authorized and validly issued as fully paid and
                           non-assessable;

                  (v)      each of the Trust, ManagementCo and Advantage Oil &
                           Gas has all necessary trust or corporate power and
                           authority to enter into this agreement and the
                           Material Agreements and to perform its obligations,
                           as applicable, and this agreement and the Material
                           Agreements have been duly authorized, executed and
                           delivered, as applicable, by the Trust, Advantage Oil
                           & Gas and ManagementCo, respectively, and constitute
                           legal, valid and binding obligations of each of the


                                       27


                           Trust, Advantage Oil & Gas and ManagementCo,
                           enforceable against the Trust, Advantage Oil & Gas
                           and ManagementCo, as applicable, in accordance with
                           their terms except that the validity, binding effect
                           and enforceability of the terms of agreements and
                           documents are subject to the qualification that such
                           validity, binding effect and enforceability may be
                           limited by:

                           (A)     applicable bankruptcy, insolvency,
                                   moratorium, reorganization or other laws
                                   affecting creditors' rights generally;

                           (B)     equitable remedies, including the remedies of
                                   specific performance and injunctive relief,
                                   being available only in the discretion of the
                                   applicable court;

                           (C)     the statutory and inherent powers of a court
                                   to grant relief from forfeiture, to stay
                                   execution of proceedings before it and to
                                   stay executions on judgments;

                           (D)     the applicable laws regarding limitations of
                                   actions;

                           (E)     enforceability of provisions which purport to
                                   sever any provision which is prohibited or
                                   unenforceable under applicable law without
                                   affecting the enforceability or validity of
                                   the remainder of such document would be
                                   determined only in the discretion of the
                                   court;

                           (F)     enforceability of the provisions exculpating
                                   a party from liability or duty otherwise owed
                                   by it may be limited under applicable law;
                                   and

                           (G)     that rights to indemnity, contribution and
                                   waiver under the documents may be limited or
                                   unavailable under applicable law;

                  (vi)     the execution and delivery of this agreement and the
                           fulfilment of the terms hereof by each of the Trust,
                           Advantage Oil & Gas and ManagementCo, and the
                           performance of and compliance with the terms of this
                           agreement by the Trust, Advantage Oil & Gas and
                           ManagementCo does not and will not result in a breach
                           of, or constitute a default under, and does not
                           create a state of facts which, after notice or lapse
                           of time or both, will result in a breach of or
                           constitute a default under, any applicable laws or
                           any term or provision of the Trust Indenture, the
                           articles, by-laws or resolutions of the unitholders
                           or the directors or shareholders of the Trust,
                           Advantage Oil & Gas or ManagementCo, as applicable,
                           or any mortgage, note, indenture, contract, agreement
                           (written or oral), instrument, lease or other
                           document to which the Trust, Advantage Oil & Gas or
                           ManagementCo is a party or by which it is bound, of
                           which such counsel is aware including, without
                           limitation, the Material Agreements, which default
                           might reasonably be expected to materially adversely
                           affect the business, operations, capital or condition
                           (financial or otherwise) of the Trust or its assets
                           (taken as a whole);

                  (vii)    the form of the definitive certificate representing
                           the Trust Units has been approved and adopted by the
                           Trust and each complies with all legal requirements
                           (including all applicable requirements of the
                           Exchange) relating thereto;


                                       28


                  (viii)   the Offered Securities have been duly and validly
                           created, allotted and issued as fully paid and
                           non-assessable Trust Units;

                  (ix)     the Offered Securities conform in all material
                           respects with the description thereof contained in
                           the Prospectuses;

                  (x)      the Offered Securities are eligible investments as
                           set out under the heading "Eligibility for
                           Investment" in the Prospectuses;

                  (xi)     all necessary documents have been filed, all
                           necessary proceedings have been taken and all legal
                           requirements have been fulfilled as required under
                           the Applicable Securities Laws of each of the
                           Qualifying Provinces in order to qualify the Offered
                           Securities for distribution and sale to the public in
                           each of such Qualifying Provinces by or through
                           investment dealers and brokers duly registered under
                           the applicable laws of such provinces who have
                           complied with the relevant provisions of such
                           Applicable Securities Laws;

                  (xii)    the Trust is a "reporting issuer" not in default of
                           any requirement of the Securities Act (Alberta) and
                           the regulations thereunder and has a similar status
                           under the Applicable Securities Laws of each of the
                           other Qualifying Provinces that have the "reporting
                           issuer" concept;

                  (xiii)   each of the Trust and Advantage Oil & Gas have the
                           necessary power and authority to execute and deliver
                           the Prospectuses and all necessary action has been
                           taken by each of the Trust and Advantage Oil & Gas to
                           authorize the execution and delivery by it of the
                           Prospectuses and the filing thereof, as the case may
                           be, in each of the Qualifying Provinces in accordance
                           with Applicable Securities Laws;

                  (xiv)    subject to the qualifications and assumptions set out
                           therein, the statements in the Prospectus under the
                           heading "Canadian Federal Income Tax Considerations"
                           constitute a fair summary of the principal Canadian
                           federal income tax consequences arising under the Tax
                           Act to persons referred to therein who will hold the
                           Offered Securities;

                  (xv)     all laws of the Province of Quebec relating to the
                           use of the French language have been complied with in
                           connection with the sale of the Offered Securities to
                           purchasers in the Province of Quebec;

                  (xvi)    the Offered Securities are conditionally listed and,
                           upon notification to the Exchange of the issuance and
                           sale thereof and fulfilment of the conditions of the
                           Exchange, will be posted for trading on the Exchange;

                  (xvii)   the authorized and issued capital of the Trust; and

                  (xviii)  Computershare Trust Company of Canada, at its
                           principal offices in Calgary, Alberta and Toronto,
                           Ontario has been duly appointed the transfer agent
                           and registrar for the Trust Units,


                                       29


                  and as to all other legal matters, including compliance with
                  Applicable Securities Laws in any way connected with the
                  issuance, sale and delivery of the Offered Securities as the
                  Underwriters may reasonably request.

                  It is understood that Trust's counsel may rely on the opinions
                  of local counsel acceptable to them as to matters governed by
                  the laws of jurisdictions other than where they are qualified
                  to practice law, and on certificates of officers of the Trust,
                  Advantage Oil & Gas, ManagementCo, the transfer agent and the
                  Trust's auditors as to relevant matters of fact. It is further
                  understood that the Underwriters' counsel may rely on the
                  opinion of the Trust's counsel as to matters which
                  specifically relate to the Trust, Advantage Oil & Gas,
                  ManagementCo and the Offered Securities;

         (b)      a certificate of each of the Trust and Advantage Oil & Gas
                  dated the Closing Date addressed to the Underwriters and
                  signed on behalf of the Trust and Advantage Oil & Gas by the
                  President and Chief Executive Officer and the Vice President,
                  Finance and Chief Financial Officer of Advantage Oil & Gas or
                  such other officers or directors of Advantage Oil & Gas
                  satisfactory to the Underwriters, acting reasonably,
                  certifying that:

                  (i)      each of the Trust and Advantage Oil & Gas has
                           complied with and satisfied in all material respects
                           all terms and conditions of this agreement on its
                           part to be complied with or satisfied at or prior to
                           the Closing Time;

                  (ii)     the representations and warranties of the Trust and
                           Advantage Oil & Gas set forth in this agreement are
                           true and correct in all material respects at the
                           Closing Time as if made at such time; and

                  (iii)    no event of a nature referred to in paragraphs 6(a),
                           6(b), 12(a)(i), (ii) or (vi) has occurred or to the
                           knowledge of such officer is pending, contemplated or
                           threatened;

                  and the Underwriters shall have no knowledge to the contrary;

         (c)      a certificate of ManagementCo dated the Closing Date addressed
                  to the Underwriters and signed on behalf of ManagementCo by
                  the President and Vice President of ManagementCo or such other
                  officers or directors of ManagementCo satisfactory to the
                  Underwriters, acting reasonably, certifying that:

                  (i)      ManagementCo has complied with and satisfied in all
                           material respects all terms and conditions of this
                           agreement on its part to be complied with or
                           satisfied at or prior to the Closing Time; and

                  (ii)     the representations and warranties of ManagementCo
                           set forth in this agreement are true and correct in
                           all material respects at the Closing Time as if made
                           at such time;

                  and the Underwriters shall have no knowledge to the contrary;

         (d)      a comfort letter of each of the Trust's auditors, Anadarko's
                  auditors and MarkWest's auditors addressed to the Underwriters
                  and dated the Closing Date satisfactory in form and substance
                  to the Underwriters, acting reasonably, bringing the


                                       30


                  information contained in the comfort letters referred to in
                  paragraph 4(d) hereof up to the Closing Time which comfort
                  letter shall be not more than two Business Days prior to the
                  Closing Date;

         (e)      evidence satisfactory to the Underwriters that the Offered
                  Securities have been conditionally listed on the Exchange not
                  later than the close of business on the last Business Day
                  preceding the Closing Date; and

         (f)      such other certificates and documents as the Underwriters may
                  request, acting reasonably.

14.      DELIVERIES

The sale of the Offered Securities shall be completed at the Closing Time at the
offices of the Trust's counsel in Calgary, Alberta or at such other place as the
Trust and the Underwriters may agree. Subject to the conditions set forth in
Section 13, the Underwriters, on the Closing Date, shall deliver to the Trust a
wire transfer payable to the Trust at par in Calgary in respect of the Offered
Securities (less the fee of the Underwriters to be calculated as provided in
Section 2(a)) against delivery by the Trust of:

         (a)      the opinions, certificates and documents referred to in
                  Section 13; and

         (b)      definitive certificates representing, in the aggregate, all of
                  the Offered Securities, registered in the name of Scotia
                  Capital Inc. or in such name or names as the Underwriters
                  shall notify the Trust in writing not less than twenty four
                  (24) hours prior to the Closing Time.

15.      RESTRICTIONS ON OFFERINGS

The Trust agrees that, prior to 90 days after the Closing Date except in respect
of Trust Units issued on conversion of the 8.25% Debentures, the 9% Debentures,
the 10% Debentures, the 7.75% Debentures, the 7.50% Debentures, Exchangeable
Shares or upon the exercise of trust unit incentive rights, it shall not,
directly or indirectly, sell or offer to sell any Trust Units, or otherwise
lend, transfer or dispose of any securities exchangeable, convertible or
exercisable into Trust Units or enter into any swap or other arrangement that
transfers to another, in whole or in part, any of the economic consequences of
ownership of Trust Units, whether any such transaction is settled by delivery of
Trust Units or other such securities, in cash or otherwise, or announce an
intention to do any of the foregoing without the consent of Scotia Capital Inc.,
such consent not to be unreasonably withheld.

16.      NOTICES

Any notice or other communication to be given hereunder shall, in the case of
notice to be given to the Trust, Advantage Oil & Gas or ManagementCo, be
addressed to ManagementCo, c/o Kelly Drader, President, at the above address,
Fax No. (403) 781-2398 with a copy to:

         Burnet, Duckworth & Palmer LLP
         1400, 350 - 7th Avenue SW
         Calgary, Alberta T2P 3N9

         Attention:        Jay Reid
         Fax No.: (403) 260-0330


                                       31


and, in the case of notice to be given to the Underwriters, be addressed to:

         Scotia Capital Inc.
         Suite 1800, Scotia Centre
         700 - 2nd Street SW
         Calgary, Alberta T2P 2N7

         Attention:        Mark Herman
         Fax No.: (403) 298-4099

         BMO Nesbitt Burns Inc.
         2200, 333 - 7th Avenue SW
         Calgary, Alberta T2P 2Z1

         Attention:        Jason J. Zabinsky
         Fax No.: (403) 515-1535

         National Bank Financial Inc.
         Suite 2802, TransCanada Tower
         450 - 1st Street SW
         Calgary, Alberta T2P 5H1

         Attention:        David M. Vetters
         Fax No.: (403) 265-0543

         RBC Dominion Securities Inc.
         Suite 1100, Bankers Hall West
         888 - 3rd Street SW
         Calgary, Alberta T2P 5C5

         Attention:        Craig E. Kelly
         Fax No.: (403) 299-6901

         CIBC World Markets Inc.
         1100, 855 - 2nd Street SW
         Calgary, Alberta T2P 4J7

         Attention:        T. Timothy Kitchen
         Fax No.: (403) 260-0524

         Raymond James Ltd.
         2500, 707 - 8th Avenue S.W.
         Calgary, Alberta T2P 1H5

         Attention:        Edward J. Bereznicki
         Fax No.: (403) 509-0535

         FirstEnergy Capital Corp.
         1600, 333 - 7th Avenue SW
         Calgary, Alberta T2P 2Z1

         Attention:        Hugh R. Sanderson
         Fax No.  (403) 262-0688



                                       32


and a copy to:

         Macleod Dixon LLP
         3700 Canterra Tower
         400 - 3rd Avenue SW
         Calgary, Alberta T2P 4H2

         Attention:        Kent D. Kufeldt
         Fax No.: (403) 264-5973

or to such other address as the party may designate by notice given to the
other. Each communication shall be personally delivered to the addressee or sent
by facsimile transmission to the addressee, and:

         (a)      a communication which is personally delivered shall, if
                  delivered before 4:00 p.m. (local time at the place of
                  delivery) on a Business Day, be deemed to be given and
                  received on that day and, in any other case be deemed to be
                  given and received on the first Business Day following the day
                  on which it is delivered; and

         (b)      a communication which is sent by facsimile transmission shall,
                  if sent on a Business Day before 4:00 p.m. (local time at the
                  place of receipt), be deemed to be given and received on that
                  day and, in any other case, be deemed to be given and received
                  on the first Business Day following the day on which it is
                  sent.

17.      CONDITIONS

All terms, covenants and conditions of this agreement to be performed by the
Trust, Advantage Oil & Gas and ManagementCo shall be construed as conditions,
and any breach or failure to comply with any material terms and conditions which
are for the benefit of the Underwriters shall entitle the Underwriters to
terminate their obligations to purchase the Offered Securities, by written
notice to that effect given to the Trust prior to the Closing Time. The
Underwriters may waive in whole or in part any breach of, default under or
non-compliance with any representation, warranty, term or condition hereof, or
extend the time for compliance therewith, without prejudice to any of their
rights in respect of any other representation, warranty, term or condition
hereof or any other breach of, default under or non-compliance with any other
representation, warranty, term or condition hereof, provided that any such
waiver or extension shall be binding on the Underwriters only if the same is in
writing.

18.      SURVIVAL OF REPRESENTATIONS AND WARRANTIES

All representations, warranties, terms and conditions herein (including, without
limitation, those contained in paragraphs 7 and 8 hereof) or contained in
certificates or documents submitted pursuant to or in connection with the
transactions contemplated herein shall survive the payment by the Underwriters
for the Offered Securities, the termination of this agreement and the
distribution of the Offered Securities pursuant to the Prospectus and shall
continue in full force and effect for the benefit of the Underwriters regardless
of any investigation by or on behalf of the Underwriters with respect thereto.


                                       33


19.      SEVERAL LIABILITY OF UNDERWRITERS

The Underwriters' rights and obligations under this agreement are several and
not joint and several including, without limitation, that:

         (a)      each of the Underwriters shall be obligated to purchase only
                  the percentage of the total number of Offered Securities set
                  forth opposite their names set forth in this paragraph 19; and

         (b)      if an Underwriter (a "Refusing Underwriter") does not complete
                  the purchase and sale of the Offered Securities which that
                  Underwriter has agreed to purchase under this Agreement (other
                  than in accordance with section 12) (the "Defaulted
                  Securities"), the remaining Underwriters (the "Continuing
                  Underwriters") will be entitled, at their option, to purchase
                  all but not less than all of the Defaulted Securities pro rata
                  according to the number of Offered Securities to have been
                  acquired by the Continuing Underwriters under this Agreement
                  or in any proportion agreed upon, in writing, by the
                  Continuing Underwriters. If no such arrangement has been made
                  and the number of Defaulted Securities to be purchased by the
                  Refusing Underwriter(s) does not exceed 3% of the Offered
                  Securities, the Continuing Underwriters will be obligated to
                  purchase the Defaulted Securities on the terms set out in this
                  Agreement in proportion to their obligations under this
                  Agreement. If the number of Defaulted Securities to be
                  purchased by the Refusing Underwriters exceeds 3% of the
                  Offered Securities, the Continuing Underwriters will not be
                  obligated to purchase the Defaulted Securities and, if the
                  Continuing Underwriters do not elect to purchase the Defaulted
                  Securities:

                  (i)      the Continuing Underwriters will not be obligated to
                           purchase any of the Offered Securities;

                  (ii)     the Trust will not be obligated to sell less than all
                           of the Offered Securities; and

                  (iii)    the Trust, Advantage Oil & Gas and ManagementCo will
                           be entitled to terminate their obligations under this
                           Agreement, in which event there will be no further
                           liability on the part of such parties or the
                           Continuing Underwriters, except pursuant to the
                           provisions of sections 9, 10 and 11 hereof.

The applicable percentage of the total number of Offered Securities which each
of the Underwriters shall be separately obligated to purchase is as follows:

         Scotia Capital Inc.                     39%
         BMO Nesbitt Burns Inc.                17.5%
         National Bank Financial Inc.          17.5%
         RBC Dominion Securities Inc.            13%
         CIBC World Markets Inc.                 10%
         Raymond James Ltd.                       2%
         FirstEnergy Capital Corp.                1%

Nothing in this agreement shall obligate the Trust to sell one or any of the
Underwriters less than all of the Offered Securities or shall relieve any
Underwriter in default from liability to the Trust, Advantage Oil & Gas or
ManagementCo, or to any non-defaulting Underwriter in respect of its default
hereunder. In the event of a termination by the Trust, Advantage Oil & Gas or
ManagementCo of their obligations under this agreement, there shall be no


                                       34


further liability on the part of the Trust, Advantage Oil & Gas or ManagementCo
to the Underwriters except in respect of any liability which may have arisen or
may thereafter arise under sections 9, 10 and 11.

20.      AUTHORITY TO BIND UNDERWRITERS

The Trust, Advantage Oil & Gas and ManagementCo shall be entitled to and shall
act on any notice, waiver, extension or communication given by or on behalf of
the Underwriters by Scotia Capital Inc., which shall represent the Underwriters
and which shall have the authority to bind the Underwriters in respect of all
matters hereunder, except in respect of any settlement under paragraphs 9 or 10,
any matter referred to in paragraph or any agreement under paragraph 20.

While not affecting the foregoing, Scotia Capital Inc. shall consult with the
other Underwriters with respect to any such notice, waiver, extension or other
communication.

21.      UNDERWRITERS COVENANTS

Each of the Underwriters covenants and agrees with the Trust that it will:

         (a)      offer the Offered Securities for sale to the public only in
                  the Qualifying Provinces;

         (b)      conduct activities in connection with the proposed offer and
                  sale of the Offered Securities in compliance with all
                  Applicable Securities Laws and cause a similar covenant to be
                  contained in any agreement entered into with any Selling
                  Dealer Group established in connection with the distribution
                  of the Offered Securities;

         (c)      use all reasonable efforts to complete the distribution of the
                  Offered Securities as soon as possible;

         (d)      not solicit subscriptions for the Offered Securities, trade in
                  Offered Securities or otherwise do any act in furtherance of a
                  trade of Offered Securities outside of the Qualifying
                  Provinces including, without limitation:

                  (i)      the Underwriters agree that they will not (and will
                           cause the Selling Dealer Group not to) sell or offer
                           to sell the Offered Securities within the United
                           States of America, its territories or possessions
                           (the "U.S.") or to, or for the account of, "United
                           States persons" (as that term is defined in
                           Regulation S to the United States Securities Act of
                           1933, as amended (the "1933 ACT"));

                  (ii)     at the time any buy order for the Offered Securities
                           is originated, the buyer is outside the U.S., or the
                           Underwriters or any person acting on its behalf
                           reasonably believes the buyer is outside the U.S. and
                           the buyer shall not be a "United States person"; and

                  (iii)    no "directed selling efforts" (as that term is
                           defined under Regulation S of the 1933 Act) have been
                           or will be made in the U.S. by the Underwriters or
                           any person acting on behalf of the Underwriters in
                           respect of the sale of the Offered Securities offered
                           for sale hereunder; and

         (e)      as soon as reasonably practicable after the Closing Date
                  provide the Trust with a break down in writing of the number
                  of Offered Securities sold in each of the Qualifying Provinces
                  and, upon completion of the distribution of the Offered


                                       35


                  Securities, provide to the Trust, the Exchange and to the
                  Securities Commissions prompt notice in writing to that
                  effect.

22.      SEVERANCE

If one or more of the provisions contained herein shall, for any reason, be held
to be invalid, illegal or unenforceable in any respect, such invalidity,
illegality or unenforceability shall not affect any other provision of this
agreement, but this agreement shall be construed as if such invalid, illegal or
unenforceable provision or provisions had never been contained herein.

23.      RELATIONSHIP BETWEEN THE TRUST, ADVANTAGE OIL & GAS AND MANAGEMENTCO
         AND THE UNDERWRITERS

The Trust, Advantage Oil & Gas and ManagementCo: (i) acknowledge and agree that
the Underwriters have certain statutory obligations as registrants under the
Applicable Securities Laws and have fiduciary relationships with their clients;
(ii) acknowledge and agree that the Underwriters are neither the agents of the
Trust, Advantage Oil & Gas or ManagementCo nor otherwise fiduciaries of the
Trust, Advantage Oil & Gas or ManagementCo; and (iii) consent to the
Underwriters acting hereunder while continuing to act for their clients. To the
extent that the Underwriters' statutory obligations as registrants under
Applicable Securities Laws or fiduciary relationships with their clients
conflicts with their obligations hereunder the Underwriters shall be entitled to
fulfil their statutory obligations as registrants under Applicable Securities
Laws and their duties to their clients. Nothing in this agreement shall be
interpreted to prevent the Underwriters from fulfilling their statutory
obligations as registrants under Applicable Securities Laws or to act as a
fiduciary of their clients.

24.      STABILIZATION

In connection with the distribution of the Offered Securities, the Underwriters
may over-allot or effect transactions which stabilize or maintain the market
price of the securities of the Trust at levels other than those which might
otherwise prevail in the open market, but in each case only as permitted by
Applicable Securities Laws. Such stabilizing transactions, if any, may be
discontinued at any time.

25.      GOVERNING LAW

This agreement shall be governed by and construed in accordance with the laws of
the Province of Alberta and the laws of Canada applicable therein. Each of the
Trust, Advantage Oil & Gas and ManagementCo and the Underwriters hereby attorn
to the non-exclusive jurisdiction of the courts of the Province of Alberta.

26.      TIME OF THE ESSENCE TIME SHALL BE OF THE ESSENCE OF THIS AGREEMENT.

27.      COUNTERPART EXECUTION

This agreement may be executed in one or more counterparts each of which so
executed shall constitute an original and all of which together shall constitute
one and the same agreement. Delivery of counterparts may be effected by
facsimile transmission.

28.      CONTRACTUAL OBLIGATIONS OF TRUST

The parties hereto acknowledge that the obligations of the Trust hereunder shall
not be personally binding upon the Trustee, or any of the unitholders of the
Trust and that any recourse against the Trust, the Trustee or any unitholder in


                                       36


any manner in respect of any indebtedness, obligation or liability of the Trust
arising hereunder or arising in connection herewith or from the matters to which
this agreement relates, if any, including without limitation claims based on
negligence or otherwise tortious behaviour, shall be limited to, and satisfied
only out of, the Trust Fund, as defined in the Trust Indenture, as amended from
time to time.

29.      FURTHER ASSURANCES

Each party to this agreement covenants and agrees that, from time to time, it
will, at the request of the requesting party, execute and deliver all such
documents and do all such other acts and things as any party hereto, acting
reasonably, may from time to time request be executed or done in order to better
evidence or perfect or effectuate any provision of this agreement or of any
agreement or other document executed pursuant to this agreement or any of the
respective obligations intended to be created hereby or thereby.

30.      USE OF PROCEEDS

Each of Advantage Oil & Gas, ManagementCo and the Trust hereby covenant and
agree to use the net proceeds of the sale of the Offered Securities hereunder in
accordance with the disclosure in the Prospectus.

31.      ENTIRE AGREEMENT

It is understood that the terms and conditions of this agreement supersede any
previous verbal or written agreement between the Underwriters and the Trust,
Advantage Oil & Gas or ManagementCo.

If the foregoing is in accordance with your understanding and is agreed to by
you, please confirm your acceptance by signing the enclosed copies of this
letter at the place indicated and by returning the same to Scotia Capital Inc.



                               SCOTIA CAPITAL INC.

                               Per: "MARK HERMAN"

                                                                
BMO NESBITT BURNS INC.                                             NATIONAL BANK FINANCIAL INC.

Per:  Jason J. Zabinsky                                            Per:  David M. Vetters


                           RBC DOMINION SECURITIES INC.

                              Per:  Craig E. Kelly



                             CIBC WORLD MARKETS INC.

                            Per:  T. Timothy Kitchen



                               RAYMOND JAMES LTD.

                           Per:  Edward J. Bereznicki


                            FIRSTENERGY CAPITAL CORP.

                             Per:  Hugh R. Sanderon





ACCEPTED AND AGREED to this 19th
day of January, 2005


ADVANTAGE ENERGY INCOME FUND,               ADVANTAGE INVESTMENT MANAGEMENT LTD.
by Advantage Oil & Gas Ltd.

Per:  Peter A. Hanrahan                     Per:  Patrick J. Cairns



ADVANTAGE OIL & GAS LTD.

Per:  Peter A. Hanrahan