<DOCUMENT>
<TYPE>EX-99
<SEQUENCE>20
<FILENAME>ex99_17form40-f.txt
<DESCRIPTION>EXHIBIT 99.17
<TEXT>
                                                                   EXHIBIT 99.17
                                                                   -------------




                             MATERIAL CHANGE REPORT




1.       Reporting Issuer:

         Vermilion Energy Trust
         2800, 400 - 4th Avenue S.W.
         Calgary, Alberta T2P 0J4

2.       Date of Material Change:

         March 19, 2004

3.       Press Release:

         On March 22, 2004 at Calgary, Alberta, a news release was issued and
         disseminated through Canada NewsWire.

4.       Summary of Material Change:

         On March 22, 2004, Vermilion Energy Trust (the "Trust") together with
         its subsidiary, Aventura Energy Inc. ("Aventura") announced that
         Aventura had entered into an agreement with BG Group, through its
         wholly-owned Canadian subsidiary, BG Canada Ltd., whereby BG Canada
         Ltd. will offer to acquire all of the outstanding shares of Aventura
         for $5.10 in cash per share (the "Offer"). The Offer is intended to
         expire at 7:00 p.m. (Calgary time) on May 4, 2004.

         In connection with the Offer, the Trust and its operating subsidiary,
         Vermilion Resources Ltd. ("Vermilion"), agreed to irrevocably tender
         Vermilion's 32,271,590 common shares of Aventura to the Offer
         (representing approximately 68.4% of the outstanding common shares of
         Aventura on a partially diluted basis (which assumes all in-the-money
         options to acquire common shares of Aventura are exercised in full))
         pursuant to a lock-up agreement with BG Canada Ltd. and BG Energy
         Holdings Limited. If the Offer is successful, Vermilion will receive
         proceeds of approximately $164.6 million from the tender of its
         Aventura shares to the Offer.

5.       Full Description of Material Change:

         On March 22, 2004, Vermilion Energy Trust (the "Trust") together with
         its subsidiary, Aventura Energy Inc. ("Aventura") announced that
         Aventura had entered into an agreement with BG Group, through its
         wholly-owned Canadian subsidiary, BG Canada Ltd., whereby BG Canada
         Ltd. will offer to acquire all of the outstanding shares of Aventura
         for $5.10 in cash per share (the "Offer"). The Offer is intended to
         expire at 7:00 p.m. (Calgary time) on May 4, 2004.

         In connection with the Offer, the Trust and its operating subsidiary,
         Vermilion Resources Ltd. ("Vermilion"), agreed to irrevocably tender
         Vermilion's 32,271,590 common shares of Aventura to the Offer
         (representing approximately 68.4% of the outstanding common shares of
         Aventura on a partially diluted basis (which assumes all in-the-money
         options to acquire common shares of Aventura are exercised in full))
         pursuant to a lock-up agreement with BG Canada Ltd. and BG Energy
         Holdings Limited. If the Offer is successful, Vermilion will receive
         proceeds of approximately $164.6 million from the tender of its
         Aventura shares to the Offer.

<PAGE>
                                      -2-


         On March 19, 2004, Vermilion and the Trust entered into a Lock-Up
         Agreement with BG Energy Holdings Limited ("BGEH") and BG Canada Ltd.
         (the "Offeror"). Pursuant to the Lock-Up Agreement, Vermilion and the
         Trust represented that Vermilion is the beneficial owner of 32,271,590
         common shares of Aventura and irrevocably agreed to accept the Offer
         and tender such common shares to the Offer.

         The following is a summary of the principal terms of the Lock-Up
         Agreement.

         AGREEMENT TO DEPOSIT: Vermilion and the Trust have irrevocably agreed
         to accept the Offer and deposit the common shares of Aventura held by
         Vermilion to the Offer on the terms set out in the Lock-Up Agreement.

         COMPLIANCE WITH SUPPORT AGREEMENT: The Offeror has agreed with
         Vermilion and the Trust that it would make the Offer on the terms and
         conditions outlined in the Support Agreement entered into between
         Aventura, BGEH and the Offeror dated March 19, 2004 (the "Support
         Agreement").

         TERMINATION OF THE LOCK-UP AGREEMENT: The Lock-Up Agreement may be
         terminated in certain circumstances, including:

         (a)      by mutual consent of BGEH, the Offeror, Vermilion and the
                  Trust;

         (b)      by Vermilion and the Trust, BGEH or the Offeror, if the
                  conditions to the Offer are not satisfied or waived by the
                  Offeror in its sole discretion prior to the expiry time of the
                  Offer provided that Vermilion and the Trust may not exercise
                  this termination right if the conditions to the Offer have not
                  been satisfied as a result of a breach by or the Trust of the
                  Lock-up Agreement or a breach by Aventura of the Support
                  Agreement;

         (c)      by the Offeror and/or BGEH if:

                  (i)      the Support Agreement is terminated;

                  (ii)     if Vermilion or the Trust is in default of any
                           material covenant or obligation under the Lock-Up
                           Agreement, or if any representation or warranty of
                           Vermilion or the Trust in such agreement was untrue
                           or incorrect at the date of Lock-up Agreement, or, if
                           not already qualified by a materiality concept, was
                           untrue or incorrect in any material respect; or

         (d)      by Vermilion and the Trust:

                  (i)      if after the 60th day after the Offer is commenced,
                           the Offeror has not taken up and paid for all common
                           shares of Aventura deposited under the Offer unless
                           the failure of the Offeror to take up and pay for
                           common shares arises as a result of the breach by
                           Vermilion and/or the Trust or Aventura of any
                           material covenant or obligation under the Lock-Up
                           Agreement or the Support Agreement, respectively, or
                           as a result of any representation or warranty of
                           Vermilion or the Trust or Aventura under the Lock-Up
                           Agreement or the Support Agreement, respectively,
                           being untrue or incorrect or if not already qualified
                           by a materiality concept (other than with respect to
                           title to the common shares held by Vermilion and
                           outstanding share capital) untrue or incorrect in any
                           material respect;

<PAGE>
                                      -3-


                           provided, however, that if the take up and payment by
                           the Offeror for common shares deposited under the
                           Offer is delayed by:

                           (A)     an injunction or order of a court or
                                   regulatory authority of competent
                                   jurisdiction; or

                           (B)     the Offeror not having obtained any
                                   regulatory waiver, consent or approval which
                                   is necessary to permit the Offeror to take up
                                   and pay for common shares deposited under the
                                   Offer or necessary for Aventura to continue
                                   to carry on its business as currently
                                   conducted;

                           then, provided that such injunction or order is being
                           contested or appealed or such regulatory waiver,
                           consent or approval is being actively sought, as
                           applicable, the Lock-Up Agreement shall not be
                           terminated pursuant to this provision until the
                           earlier of:

                           (C)     90 days after the Offer is commenced; and

                           (D)     the 10th business day following the date on
                                   which such injunction or order ceases to be
                                   in effect or such waiver, consent or approval
                                   is obtained, as applicable;

                           and provided further that if the board of directors
                           of Aventura implements a shareholders' right plan,
                           then the Lock-Up Agreement shall not be terminated
                           pursuant to this provision until the earlier of:

                           (E)     180 days after the Offer is commenced; and

                           (F)     the 10th business day following the date on
                                   which such shareholders' rights plan is
                                   terminated;

                  (ii)     if the Support Agreement is terminated by BGEH or the
                           Offeror;

                  (iii)    if the Offer having expired and all of the conditions
                           having been satisfied or waived, the Offeror has not
                           taken up and paid for the common shares held by
                           Vermilion pursuant to the Offer as required under the
                           terms of the Support Agreement or Offer; or

                  (iv)     if BGEH or the Offeror is in default of any material
                           covenant or obligation under the Lock-Up Agreement,
                           or if any representation or warranty of BGEH or the
                           Offeror under such agreement shall have been untrue
                           or incorrect and if not already qualified by a
                           materiality concept untrue or incorrect in any
                           material respect.

         COVENANTS OF VERMILION AND THE TRUST: Each of Vermilion and the Trust
         has agreed that during the period commencing on the date of the Lock-Up
         Agreement and continuing until the earlier of the termination of the
         Offer and the withdrawal of the common shares of Aventura held by
         Vermilion from the Offer as permitted by the Lock-Up Agreement: (a) it
         will not and will not permit any of its representatives to take any
         action of any kind which may in any way adversely affect the success of
         the Offer; (b) it will immediately terminate any existing discussions
         with

<PAGE>
                                      -4-


         any parties (other than the Offeror) with respect to any Acquisition
         Proposal (as defined in the Lock-Up Agreement); and (c) it will not
         directly or indirectly solicit, initiate, encourage or otherwise
         facilitate inquiries or offers from any other person relating to any
         Acquisition Proposal (provided that this shall not prevent Aventura
         from complying with its obligations under the Support Agreement with
         respect to Superior Proposals (as defined in the Lock-Up Agreement));
         (d) it will notify the Offeror in writing and provide relevant details
         of any Acquisition Proposal it receives; (e) it will use its reasonable
         commercial efforts as a direct or indirect shareholder of Aventura to
         satisfy the conditions of the Offer; (f) it will exercise the voting
         rights attaching to the common shares held by Vermilion and otherwise
         use its reasonable commercial efforts to oppose any proposed action
         which might reasonably prevent or delay the successful completion of
         the Offer, or which could result in material adverse effect in respect
         of Aventura (provided that this shall not prevent Aventura from
         complying with its obligations under the Support Agreement with respect
         to Superior Proposals); (g) it will not grant any proxy or other right
         to the common shares held by Vermilion or enter into any voting
         agreement with respect to such shares; (h) it will not sell transfer,
         pledge, encumber or grant an option over any common shares held by
         Vermilion; (i) it will promptly advise the Offeror of any material
         adverse effect in respect of Aventura known to Vermilion which might
         cause the conditions to the Offer not to be satisfied; (j) it will not
         directly or indirectly purchase any additional common shares; and (k)
         it will take all such steps as are required to ensure that at the time
         at which the Offeror takes up and pays for common shares pursuant to
         the Offer, the common shares held by the Vermilion will be owned
         beneficially and of record by the Vermilion with a good and marketable
         title thereto, free and clear of any and all restrictions or
         encumbrances of any kind.

         REPRESENTATIONS AND WARRANTIES: Each of Vermilion and the Trust made
         certain customary representations and warranties to each of BGEH and
         the Offeror and each of the Offeror and BGEH made certain customary
         representations and warranties to each of Vermilion and the Trust.

         INDEMNITY: Vermilion and the Trust have agreed to jointly and severally
         indemnify BGEH and the Offeror and their respective successors, assigns
         and affiliates and their respective directors, officers, agents,
         employees and shareholders for incorrectness in or breaches of the
         Lock-Up Agreement or breaches by Aventura of the Support Agreement, in
         each case discovered prior to the take up and payment for common shares
         deposited under the Offer, to a maximum amount of $9,000,000 (except in
         the case of intentional misrepresentation, intentional breach or fraud
         where the indemnification obligations are not limited in any way). If
         any such breaches are discovered after the take up and payment for
         common shares deposited under the Offer, the indemnification
         obligations of Vermilion and the Trust will extend to the total amount
         paid by the Offeror to Vermilion for its common shares (except in the
         case of intentional misrepresentation, intentional breach or fraud, and
         with except in the case of breaches of representations and warranties
         relating to tax matters, pensions and employee benefits and interested
         party transactions where the indemnification obligations are not
         limited in any way). Vermilion and the Trust have also provided full
         indemnities in respect of specific matters, including claims relating
         to the management or disposition of Aventura's former Argentine
         subsidiary and the surrender or cancellation of stock options of
         Aventura. With certain exceptions, indemnification payments are not
         required to be made to the Offeror or BGEH until the aggregate of such
         claims exceeds US$3,000,000.

         In the event of any breach by Vermilion or the Trust of the Lock-Up
         Agreement or by Aventura of the Support Agreement discovered prior to
         the take up and payment for common shares deposited under the Offer
         that results in a failure to consummate the transactions provided for
         in

<PAGE>
                                      -5-


         the Lock-Up Agreement, the termination of such agreement or the
         termination of the Support Agreement, and within six months of the
         expiry of the Offer, Vermilion and/or the Trust enter into an agreement
         for the sale of all or some of the common shares of Aventura held by
         them to a third party for more than $5.10 per share in cash or other
         consideration, then they shall be jointly and severally liable to pay
         to BGEH the greater of $9,000,000 and the aggregate amount which they
         received on the sale of such common shares in excess of the amount that
         the Offeror had agreed to pay to Vermilion in respect of the Offer.

6.       Reliance on Section 146(2) of the SECURITIES ACT (Alberta), Section
         85(2) of the SECURITIES ACT (British Columbia), Section 75(3) of the
         SECURITIES ACT (Ontario) and Section 74 of the SECURITIES ACT (Quebec):

         Not Applicable

7.       Omitted Information:

         Not Applicable

8.       Senior Officers:

         For further information contact Lorenzo Donadeo, President and Chief
         Executive Officer by telephone at (403) 269-4884 or by fax at (403)
         269-4880.

9.       Statement of Senior Officer:

         The foregoing accurately discloses the material change referred to
herein.



DATED at Calgary, Alberta this 29th day of March, 2004.


                                VERMILION ENERGY TRUST, by its
                                Administrator, Vermilion Resources Ltd.


                                Per: /s/ Lorenzo Donadeo
                                     ---------------------
                                     Lorenzo Donadeo
                                     President and Chief Executive Officer


IT IS AN OFFENCE UNDER THE SECURITIES ACT AND THE SECURITIES REGULATIONS FOR A
PERSON OR COMPANY TO MAKE A STATEMENT IN A DOCUMENT REQUIRED TO BE FILED OR
FURNISHED UNDER THE ACT OR THE REGULATIONS THAT, AT THE TIME AND IN THE LIGHT OF
THE CIRCUMSTANCES UNDER WHICH IT IS MADE, IS A MISREPRESENTATION



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