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                                                                   EXHIBIT 10.10

                            INDEMNIFICATION AGREEMENT


         This Indemnification Agreement ("Agreement") is made as of the ___ day
of ________, 199__, by and between Vista Energy Resources, Inc., a Delaware
corporation (the "Company"), and ______________ and his/her affiliates
(collectively referred to herein as the "Indemnitee").

                                    RECITALS

         A. This Agreement is being entered into in accordance with the terms
and conditions of the Agreement and Plan of Merger (the "Merger Agreement"),
dated May 22, 1998, among the Company, Vista Resources Partners, L.P., Midland
Resources, Inc. ("Midland") and Midland Merger Co. As an inducement for the
Indemnitee to continue such Indemnitee's services to Midland until such time as
the transactions contemplated by the Merger Agreement have occurred, the Company
has agreed to enter into this Agreement with the Indemnitee.

         B. In addition to the indemnification to which the Indemnitee is
entitled under the By-Laws of Midland (the "By-Laws") or otherwise under this
Agreement, the Company may obtain (and if obtained, will use reasonable best
efforts to keep in force, at its sole expense) insurance protecting its officers
and directors and certain other persons (including the Indemnitee) against
certain losses arising out of actual or threatened actions, suits or proceedings
to which such persons may be made or threatened to be made parties. The Company
may, however, decide not or be unable to obtain such insurance, and, if
obtained, there can be no assurance as to the continuation or renewal thereof,
or that any such insurance will provide coverage for losses to which the
Indemnitee may be exposed and for which he or she may be permitted to be
indemnified under the General Corporation Law of the State of Delaware (the
"DGCL").

         Now, Therefore, For and in consideration of the premises, the mutual
promises hereinafter set forth, the reliance of the Indemnitee hereon in
continuing to serve the Company or Another Entity in his or her present capacity
and in undertaking to serve the Company or Another Entity in any additional
capacity or capacities, the Company and the Indemnitee agree as follows:

                  1. Continued Service. The Indemnitee will continue to serve as
a director and/or an officer of the Company and/or in each such Authorized
Capacity of or for Another Entity in which he or she presently serves, in each
case so long as he or she is duly elected and qualified to serve in such
capacity or until he or she resigns or is removed, or, in the case of service to
Midland, until such time as the transactions contemplated by the Merger
Agreement have occurred.

                  2. Initial Indemnity. (a) The Company will indemnify the
Indemnitee when the Indemnitee was or is involved in any manner (including
without limitation as a party, a deponent or a witness) or is threatened to be
made so involved in any threatened, pending or completed action, suit or
proceeding, whether civil, criminal, administrative or investigative, formal or
informal, and


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any appeals therefrom (a "Proceeding") (other than a Proceeding by or in the
right of the Company), by reason of the fact that such Indemnitee is or was or
had agreed to become a director (including service as a member of any committee
of directors), officer, employee, agent and/or "controlling person" (within the
meaning of applicable securities laws) of the Company, or is or was serving or
had agreed to serve at the request of the Company as a director (including
service as a member of any committee of directors), officer, partner, member,
trustee, employee or agent (each an "Authorized Capacity") of another
corporation, partnership, joint venture, trust or other enterprise (each
"Another Entity"), or by reason of any action alleged to have been taken or
omitted in such capacity, against any and all costs, charges and expenses
(including attorneys' and others' fees), judgments, fines and amounts paid in
settlement actually and reasonably incurred by such Indemnitee in connection
with such Proceeding if the Indemnitee acted in good faith and in a manner that
such Indemnitee reasonably believed to be in or not opposed to the best
interests of the Company, and, with respect to any criminal Proceeding, the
Indemnitee had no reasonable cause to believe such Indemnitee's conduct was
unlawful. The termination of any Proceeding by judgment, order, settlement,
conviction or upon a plea of nolo contendere or its equivalent will not, of
itself, adversely affect the right of the Indemnitee to indemnification or
create a presumption that the Indemnitee did not meet the foregoing standard of
conduct to the extent applicable thereto.

                           (a) The Company will indemnify the Indemnitee when 
such Indemnitee was or is a party or is threatened to be made a party to any
Proceeding by or in the right of the Company to procure a judgment in its favor
by reason of the fact that such Indemnitee is or was or had agreed to become a
director, officer, employee, agent and/or "controlling person" (within the
meaning of applicable securities laws) of the Company, or is or was serving or
had agreed to serve at the request of the Company in an Authorized Capacity of
or for Another Entity, against any and all costs, charges and expenses
(including attorneys' and others' fees) actually and reasonably incurred by him
or her in connection with the investigation, preparation, defense, settlement or
appeal of such Proceeding if the Indemnitee acted in good faith and in a manner
that such Indemnitee reasonably believed to be in or not opposed to the best
interests of the Company, except that no indemnification will be made in respect
of any claim, issue or matter as to which the Indemnitee shall have been
adjudged to be liable to the Company unless, and only to the extent, that the
Court of Chancery or the court in which the Proceeding was brought determines
upon application that, despite the adjudication of liability but in view of all
circumstances of the case, the Indemnitee is fairly and reasonably entitled to
indemnity for such expenses which the Court of Chancery or such other court
deems proper.

                           (b) To the extent that the Indemnitee has been
successful on the merits or otherwise, including without limitation the
dismissal of a Proceeding without prejudice, in the defense of any Proceeding
referred to in Section 2(a) or Section 2(b) or in the defense of any claim,
issue or matter in any such Proceeding, the Company will indemnify such
Indemnitee against any and all costs, charges and expenses, including without
limitation attorneys' and others' fees, actually and reasonably incurred by such
Indemnitee in connection therewith.

                           (c) Any indemnification under Section 2(a) or Section
2(b) (unless ordered by a court) will be made by the Company only as authorized
in the specific case upon a


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determination, in accordance with Section 4, that such indemnification is proper
in the circumstances because the Indemnitee has met the applicable standards of
conduct set forth in Section 2(a) and Section 2(b) (the "Indemnification
Standards"). Such determination will be made in the manner set forth in Section
4(b).

                           (d) Any and all costs, charges and expenses,
including without limitation attorneys' and others' fees, actually and
reasonably incurred by the Indemnitee in defending any Proceeding will be paid
by the Company as incurred and in advance of the final disposition of such
Proceeding in accordance with the procedure set forth in Section 4(e).

                           (e) Notwithstanding anything in this Agreement to the
contrary, the Indemnitee will not be entitled to indemnification or advancement
of expenses pursuant hereto in connection with any Proceeding initiated by the
Indemnitee against the Company (except for any Proceeding initiated by the
Indemnitee pursuant to Section 6) unless the Company has joined in or consented
to the initiation of such Proceeding.

                  3. Additional Indemnification. (a) Pursuant to Section 145(f)
of the DGCL, without limiting any right which the Indemnitee may have under
Section 2, the By-Laws, the DGCL, any policy of insurance or otherwise, but
subject to the limitations set forth in Section 2(f) and to any maximum
permissible indemnity which may exist under applicable law at the time of any
request for indemnity hereunder as contemplated by this Section 3(a), the
Company will indemnify the Indemnitee against any amount which such Indemnitee
is or becomes legally obligated to pay relating to or arising out of any claim
made against such Indemnitee because of any act, failure to act or neglect or
breach of duty, including any actual or alleged error, omission, misstatement or
misleading statement, which such Indemnitee commits, suffers, permits or
acquiesces in while acting in such Indemnitee's capacity as a director, officer
or controlling person of the Company, or, at the request of the Company, in an
Authorized Capacity of or for Another Entity. The payments which the Company is
obligated to make pursuant to this Section 3 will include without limitation
damages, judgments, fines, amounts paid in settlement and reasonable charges,
costs and expenses, including expenses of investigation, preparation, defense
and settlement of Proceedings and expenses of appeal, attachment or similar
bonds; provided, however, that the Company will not be obligated under this
Section 3(a) to make any payment in connection with any claim against the
Indemnitee:

                           (i) to the extent of any fine or similar governmental
                  imposition which the Company is prohibited by applicable law
                  from paying and which results from a final, non appealable
                  order; or

                           (ii) to the extent based upon or attributable to the
                  Indemnitee gaining in fact a personal profit to which such
                  Indemnitee was not legally entitled, including without
                  limitation profits made from the purchase and sale of equity
                  securities of the Company which are recoverable by the Company
                  pursuant to Section 16(b) of the Securities Exchange Act of
                  1934, as amended (the "Exchange Act"), and profits arising
                  from transactions in securities which were effected in
                  violation of Section


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                  10(b) or Section 14(e) of the Exchange Act, including Rule
                  10b-5 or Rule 14e-3 promulgated thereunder.

The determination of whether the Indemnitee is entitled to indemnification under
this Section 3(a) shall be made in accordance with Section 4(b).

                           (b) Any and all costs, charges and expenses,
including without limitation attorneys' and others' fees, actually and
reasonably incurred by the Indemnitee in connection with any claim for which the
Indemnitee may be entitled to indemnification pursuant to Section 3(a) will be
paid by the Company as incurred and in advance of the final disposition thereof
in accordance with the procedure set forth in Section 4(e).

                  4. Certain Procedures Relating to Indemnification and
Advancement of Expenses. (a) Except as otherwise permitted or required by the
DGCL, for purposes of pursuing an Indemnitee's rights to indemnification under
Section 2(a), Section 2(b) or Section 3(a), as the case may be, the Indemnitee
may, but shall not be required to, submit to the Company (to the attention of
the Secretary) a statement of request for indemnification substantially in the
form of Exhibit 1 attached hereto (the "Indemnification Statement") stating that
such Indemnitee believes that such Indemnitee is entitled to indemnification
pursuant to this Agreement, together with such documents supporting the request
as are reasonably available to the Indemnitee and are reasonably necessary to
determine whether and to what extent the Indemnitee is entitled to
indemnification hereunder (the "Supporting Documentation"). Upon receipt of any
Indemnification Statement, the Company will promptly advise the Board of
Directors of the Company (the "Board") in writing that the Indemnitee has
requested indemnification.

                           (b) The Indemnitee's entitlement to indemnification
under Section 2(a), Section 2(b) or Section 3(a), as the case may be, will be
determined promptly following a claim by the Indemnitee for indemnification
thereunder and in any event (if the Indemnitee submits to the Company an
Indemnification Statement and Supporting Documentation) not less than 30
calendar days after receipt by the Company of such Indemnification Statement and
Supporting Documentation. The Indemnitee's entitlement to indemnification under
Section 2(a) or Section 2(b) will, subject to the next sentence, be made in one
of the following ways: (i) by the Board by a majority vote of the directors who
are not and were not parties to such Proceeding or claim ("Disinterested
Directors"), even though less than a quorum, (ii) if there are no Disinterested
Directors, or if a majority of the Disinterested Directors so direct, by written
opinion of independent legal counsel selected by a majority of the Disinterested
Directors (or, if there are no Disinterested Directors or a majority vote
thereof is not obtainable, by a majority of the entire Board), if a quorum of
the Board consisting of Disinterested Directors is not obtainable or, even if
obtainable, a quorum of Disinterested Directors so directs, (iii) by the
stockholders of the Company (but only if a majority of Disinterested Directors,
if they constitute a quorum of the Board, presents the issue of entitlement to
indemnification to the stockholders of the Company for their determination) or
(iv) as deemed to have been determined in accordance with Section 4(c). The
Indemnitee's entitlement to indemnification under Section 3(a) or, in the event
of a Change of Control (as hereinafter defined), under Section 2(a) or Section
2(b) will be determined by written opinion of independent legal


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counsel selected by the Indemnitee. Independent legal counsel selected as
described above will be a law firm or member of a law firm (x) that neither at
the time in question nor in the five years immediately preceding such time has
been retained to represent (A) the Company (or any of its affiliates) or the
Indemnitee in any matter material to either such party or (B) any other party to
the Proceeding or claim giving rise to a claim for indemnification under this
Agreement, (y) that, under the applicable standards of professional conduct then
prevailing under the law of the State of Delaware, would not be precluded from
representing either the Company or the Indemnitee in an action to determine the
Indemnitee's rights under this Agreement and (z) to which the Indemnitee or the
Company, acting therein through a majority of the Disinterested Directors or, if
there are no Disinterested Directors, by a majority of the entire Board, does
not reasonably object. If such independent legal counsel is reasonably objected
to by the Indemnitee or the Company, the Indemnitee shall select another
independent legal counsel subject to similar reasonable objection until
independent legal counsel is agreed upon. The Company will pay the fees and
expenses of such independent legal counsel.

                           (c) Submission of an Indemnification Statement and
Supporting Documentation to the Company pursuant to Section 4(b) will create a
presumption that the Indemnitee is entitled to indemnification under Section
2(a), Section 2(b) or Section 3(a), as the case may be, and thereafter the
Company will have the burden of proof to overcome that presumption in reaching a
contrary determination. In any event, if the person or persons empowered under
Section 4(b) to determine the Indemnitee's entitlement to indemnification have
not been appointed or have not made a determination within 30 calendar days
after receipt by the Company of such Indemnification Statement and Supporting
Documentation, the Indemnitee will be deemed to be entitled to indemnification
unless within such 30-calendar day period the person or persons empowered under
Section 4(b) to determine entitlement to indemnification have made a
determination, based upon clear and convincing evidence (sufficient to rebut the
foregoing presumption), that the Indemnitee is not entitled to such
indemnification and the Indemnitee has received notice within such period in
writing of such determination, which notice will (i) disclose with particularity
the evidence in support of such determination and (ii) (A) if made by
Disinterested Directors, be sworn to by all Disinterested Directors who
participated in the determination and voted to deny indemnification, (B) if made
by independent legal counsel, include a copy of the related written opinion of
such counsel or (C) if made by the stockholders of the Company, include a
certificate of the Company's Secretary as to the vote of such stockholders. The
provisions of this Section 4(c) are intended to be procedural only and will not
affect the right of the Indemnitee to indemnification under this Agreement and
any determination that the Indemnitee is not entitled to indemnification and any
failure to make the payments requested in the Indemnification Statement will be
subject to review as provided in Section 6.

                           (d) If a determination is made or deemed to have been
made pursuant to this Section 4 that the Indemnitee is entitled to
indemnification, the Company will pay to the Indemnitee the amounts to which the
Indemnitee is entitled within five business days after such determination of
entitlement to indemnification has been made or deemed to have been made.


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                           (e) In order to obtain advancement of expenses
pursuant to Section 2(e), the Indemnitee will submit to the Company a written
undertaking substantially in the form of Exhibit 2 attached hereto, executed
personally or on behalf of such Indemnitee (the "Undertaking"), stating that (i)
such Indemnitee has incurred or will incur actual expenses in defending a
Proceeding and (ii), if and to the extent required by law at the time of such
advance, such Indemnitee undertakes to repay such amounts advanced as to which
it may ultimately be determined that the Indemnitee is not entitled. In order to
obtain advancement of expenses pursuant to Section 3(b), the Indemnitee may
submit an Undertaking or, if the Indemnitee chooses not to submit an
Undertaking, shall submit such other form of request as such Indemnitee
determines to be appropriate (an "Expense Request"). Upon receipt of an
Undertaking or Expense Request, as the case may be, the Company will within 5
calendar days make payment of the costs, charges and expenses stated in the
Undertaking or Expense Request. No security will be required in connection with
any Undertaking or Expense Request and any Undertaking or Expense Request will
be accepted, and all such payments shall be made, without reference to the
Indemnitee's ability to make repayment.

                  5. Duplication of Payments. The Company will not be liable
under this Agreement to make any payment in connection with any claim made
against the Indemnitee to the extent the Indemnitee has actually received
payment (under any insurance policy, the By-Laws, the DGCL or otherwise) of the
amount otherwise payable hereunder.

                  6. Enforcement. (a) If a claim for indemnification or
advancement of expenses made to the Company pursuant to Section 4 is not timely
paid in full by the Company as required by Section 4, the Indemnitee will be
entitled to seek judicial enforcement of the Company's obligations to make such
payments. If a determination is made pursuant to Section 4 that the Indemnitee
is not entitled to indemnification or advancement of expenses hereunder, (i) the
Indemnitee may at any time thereafter seek an adjudication of such Indemnitee's
entitlement to such indemnification or advancement either, at the Indemnitee's
sole option, in (A) an appropriate court of the State of Delaware or any other
court of competent jurisdiction or (B) an arbitration to be conducted by a
single arbitrator pursuant to the rules of the American Arbitration Association,
(ii) any such judicial proceeding or arbitration will be de novo and the
Indemnitee will not be prejudiced by reason of such adverse determination, and
(iii) in any such judicial proceeding or arbitration the Company will have the
burden of proving that the Indemnitee is not entitled to indemnification or
advancement of expenses under this Agreement.

                           (b) The Company will be precluded from asserting in
any judicial proceeding or arbitration commenced pursuant to the provisions of
Section 6(a) that the procedures and presumptions of this Agreement are not
valid, binding and enforceable and will stipulate in any such court or before
any such arbitrator that the Company is bound by all the provisions of this
Agreement.

                           (c) In any action brought under Section 6(a), it will
be a defense to a claim for indemnification pursuant to Section 2(a) or Section
2(b) (but not an action brought to enforce a claim for costs, charges and
expenses incurred in defending any Proceeding in advance of its final
disposition where the Undertaking, if any is required, has been tendered to the
Company) that the


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Indemnitee has not met the standards of conduct which make it permissible under
the DGCL for the Company to indemnify the Indemnitee for the amount claimed, but
the burden of proving such defense will be on the Company. Neither the failure
of the Company (including any person or persons empowered under Section 4(b) to
determine the Indemnitee's entitlement to indemnification) to have made a
determination prior to commencement of such action that indemnification of the
Indemnitee is proper in the circumstances because such Indemnitee has met the
applicable standard of conduct set forth in the DGCL nor an actual determination
by the Company (including any person or persons empowered under Section 4(b) to
determine the Indemnitee's entitlement to indemnification) that the Indemnitee
has not met such applicable standard of conduct will be a defense to the action
or create a presumption that the Indemnitee has not met the applicable standard
of conduct.

                           (d) It is the intent of the Company that the
Indemnitee not be required to incur the expenses associated with the enforcement
of such Indemnitee's rights under this Agreement by litigation or other legal
action because the cost and expense thereof would substantially detract from the
benefits intended to be extended to the Indemnitee hereunder. Accordingly, if it
should appear to the Indemnitee that the Company has failed to comply with any
of its obligations under this Agreement, or if the Company or any other person
takes any action to declare this Agreement void or unenforceable or institutes
any action, suit or proceeding designed (or having the effect of being designed)
to deny, or to recover from, the Indemnitee the benefits intended to be provided
to the Indemnitee hereunder, the Company irrevocably authorizes the Indemnitee
from time to time to retain counsel of such Indemnitee's choice, at the expense
of the Company as hereafter provided, to represent the Indemnitee in connection
with the initiation or defense of any litigation or other legal action, whether
by or against the Company or any director, officer, stockholder or other person
affiliated with the Company, in any jurisdiction relating to enforcement of this
Agreement. Notwithstanding any existing or prior attorney-client relationship
between the Company and such counsel, the Company irrevocably consents to the
Indemnitee's entering into an attorney-client relationship with such counsel,
and in that connection the Company and the Indemnitee acknowledge that a
confidential relationship will exist between the Indemnitee and such counsel.
Regardless of the outcome thereof, the Company will pay and be solely
responsible for any and all costs, charges and expenses, including without
limitation attorneys' and others' fees, incurred by the Indemnitee (i) as a
result of the Company's failure to perform this Agreement or any provision
hereof or (ii) as a result of the Company or any person contesting the validity
or enforceability of this Agreement or any provision hereof as aforesaid.

                  7. Liability Insurance and Funding. To the extent the Company
maintains an insurance policy or policies providing directors' and officers'
liability insurance, the Indemnitee will be covered by such policy or policies,
in accordance with its or their terms, to the maximum extent of the coverage
available for a director, officer or controlling person of the Company or a
person serving at the request of the Company in an Authorized Capacity of or for
Another Entity, as the case may be. The Company may, but shall not be required
to, create a trust fund, grant a security interest or use other means (including
without limitation a letter of credit) to ensure the payment of such amounts as
may be necessary to satisfy its obligations to indemnify and advance expenses
pursuant to this Agreement.


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                  8. Change of Control. (a) If the Company sells or otherwise
disposes of all or substantially all of its assets or is a constituent
corporation in a consolidation, merger or other business combination transaction
or if there is a change of control (as defined below) of the Company, (a) the
Company will require (if it is not the surviving, resulting or acquiring
corporation therein) the surviving, resulting or acquiring corporation expressly
to assume the Company's obligations under this Agreement and to agree to
indemnify the Indemnitee to the full extent provided herein and (b), whether or
not the Company is the resulting, surviving or acquiring corporation in any such
transaction (or Change of Control), the Indemnitee will also stand in the same
position under this Agreement with respect to the resulting, surviving or
acquiring corporation as an Indemnitee would have with respect to the Company if
the transaction (or Change of Control) had not occurred.

                           (b) The Company agrees that if there is a Change of
Control of the Company (other than a Change of Control which has been approved
by a majority of the Company's Board of Directors who were directors immediately
prior to such Change of Control) then with respect to all matters thereafter
arising concerning the rights of the Indemnitee to indemnity payments and
advancement of expenses under this Agreement or any other agreement or
provisions of the Certificate of Incorporation of the Company (the
"Certificate") or the By-laws now or hereafter in effect, the Company shall seek
legal advice only from independent legal counsel selected as provided in Section
4(b). Such counsel, among other things, shall render its written opinion to the
Company and Indemnitee as to whether and to what extent the Indemnitee would be
permitted to be indemnified under applicable law. The Company agrees to pay the
reasonable fees of such independent legal counsel and to fully indemnify such
counsel against any and all expenses (including attorneys' fees), claims,
liabilities and damages arising out of or relating to this Agreement or its
engagement pursuant hereto.

                  9. Partial Indemnity. If the Indemnitee is entitled under any
provision of this Agreement to indemnification by the Company for some or a
portion of the costs, charges, expenses, judgments, fines and amounts paid in
settlement of a Proceeding but not, however, for the total amount thereof, the
Company shall nevertheless indemnify the Indemnitee for the portion thereof to
which the Indemnitee is entitled.

                  10. Nonexclusivity and Severability. (a) The right to
indemnification and advancement of expenses provided by this Agreement is not
exclusive of any other right to which the Indemnitee may be entitled under the
Certificate, the By-Laws, the DGCL, any other statute, insurance policy,
agreement, vote of stockholders or of directors or otherwise, both as to actions
in such Indemnitee's official capacity and as to actions in another capacity
while holding such office, and will continue after the Indemnitee has ceased to
serve as a director, officer or controlling person of the Company or in an
Authorized Capacity in or for Another Entity and will inure to the benefit of
such Indemnitee's successors, heirs, executors and administrators; provided,
however, that, to the extent the Indemnitee otherwise would have any greater
right to indemnification or advancement of expenses under any provision of the
Certificate or the By-Laws as in effect on the date hereof, the Indemnitee will
be deemed to have such greater right pursuant to this Agreement; and, provided
further, that, inasmuch as it is the intention of the Company to provide the
Indemnitee with the


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broadest and most favorable (to the Indemnitee) possible indemnity permitted by
applicable law (whether by legislative action or judicial decision), to the
extent that the DGCL currently permits or in the future permits (whether by
legislative action or judicial decision) any greater right to indemnification or
advancement of expenses than that provided under this Agreement as of the date
hereof, the Indemnitee will automatically, without the necessity of any further
action by the Company or the Indemnitee, be deemed to have such greater right
pursuant to this Agreement. Similarly, the Indemnitee shall have the benefit of
any future changes to the By-Laws or the Certificate which grant or permit any
greater right to indemnification or advancement of expenses.

                           (b) The Company will not adopt any amendment to the
Certificate or By-Laws the effect of which would be to deny, diminish or
encumber the Indemnitee's rights to indemnity pursuant to the Certificate, the
By-Laws, the DGCL or any other applicable law as applied to any act or failure
to act occurring in whole or in part prior to the date upon which any such
amendment was approved by the Board or the stockholders, as the case may be.
Notwithstanding the foregoing, if the Company adopts any amendment to the
Certificate or By-Laws the effect of which is to so deny, diminish or encumber
the Indemnitee's rights to such indemnity, such amendment will apply only to
acts or failures to act occurring entirely after the effective date thereof.

                           (c) If any provision or provisions of this Agreement
are held to be invalid, illegal or unenforceable for any reason whatsoever: (i)
the validity, legality and enforceability of the remaining provisions of this
Agreement (including without limitation all portions of any paragraph of this
Agreement containing any such provision held to be invalid, illegal or
unenforceable, that are not themselves invalid, illegal or unenforceable) will
not in any way be affected or impaired thereby and (ii), to the fullest extent
possible, the provisions of this Agreement (including without limitation all
portions of any paragraph of this Agreement containing any such provision held
to be invalid, illegal or unenforceable, that are not themselves invalid,
illegal or unenforceable) will be construed so as to give effect to the intent
manifested by the provision held invalid, illegal or unenforceable. No claim or
right to indemnity or advancement of expenses pursuant to Section 3 hereof shall
in any way affect or limit any right which the Indemnitee may have under Section
2 hereof, the Certificate, the By-Laws, the DGCL, any policy of insurance or
otherwise.

                  11. Governing Law. This Agreement will be governed by and
construed in accordance with the laws of the State of Delaware, without giving
effect to the principles of conflict of laws thereof.

                  12. Modification; Survival. This Agreement contains the entire
agreement of the parties relating to the subject matter hereof; provided,
however, that this provision shall not be construed to affect the Company's
obligations to the Indemnitee under the Certificate or By-Laws. This Agreement
may be modified only by an instrument in writing signed by both parties hereto.
The provisions of this Agreement will survive the death, disability, or
incapacity of the Indemnitee or the termination of the Indemnitee's service as a
director, an officer or controlling person of the Company or in an Authorized
Capacity of or for Another Entity and will inure to the benefit of the
Indemnitee's successors, heirs, executors and administrators.


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                  13. Certain Terms. (a) For purposes of this Agreement,
references to a person's capacity as a "director" shall include without
limitation such person's capacity as a member of any committee appointed by the
board of which such person is a director; references to "Another Entity" will
include employee benefit plans and Midland Resources, Inc.; references to
"fines" will include any excise taxes assessed on the Indemnitee with respect to
any employee benefit plan; and references to "serving at the request of the
Company" will include any service in any capacity which imposes duties on, or
involves services by, the Indemnitee with respect to an employee benefit plan,
its participants or beneficiaries; references to Sections or Exhibits are to
Sections or Exhibits of or to this Agreement; references to the singular will
include the plural and vice versa; and if the Indemnitee acted in good faith and
in a manner such Indemnitee reasonably believed to be in the interest of the
participants and beneficiaries of an employee benefit plan such Indemnitee will
be deemed to have acted in a "manner not opposed to the best interests of the
Company" as referred to herein.

                           (b) For purposes of this Agreement, a "Change of
Control" shall mean the first to occur of the following events: (i) any sale,
lease, exchange, or other transfer (in one transaction or series of related
transactions) of all or substantially all of the assets of the Company to any
"person" or "group" of related persons (as such terms are used in Section 13(d)
of the Exchange Act), (ii) a majority of the Board of Directors of the Company
shall consist of persons who are not Continuing Directors; or (iii) the
acquisition by any person or group (other than Natural Gas Partners II, L.P.,
Natural Gas Partners III, L.P. or any Affiliate thereof) of the power, directly
or indirectly, to vote or direct the voting of securities having more than 50%
of the ordinary voting power for the election of directors of the Company.

                           (c) For purposes of this Agreement, "Continuing
Director" shall mean, as of the date of determination, any person who (i) was a
member of the Board of Directors of the Company immediately after the Effective
Time or (ii) was nominated for election or elected to the Board of Directors of
the Company with the affirmative vote of a majority of the Continuing Directors
who were members of such Board of Directors at the time of such nomination or
election.

                           (d) "Effective Time" shall mean the time that the
proposed merger of Midland Merger Co. and Midland Resources, Inc. is effective
as such merger is contemplated by that certain Agreement and Plan of Merger,
dated as of May 22, 1998, among Vista Resources Partners, L.P., Midland
Resources, Inc., Vista Energy Resources, Inc. and Midland Merger Co.

                  14. Joint Defense. Notwithstanding anything to the contrary
contained herein, if (a) the Indemnitee elects to retain counsel in connection
with any Proceeding or claim in respect of which indemnification may be sought
by the Indemnitee against the Company pursuant to this Agreement and (b) any
other director or officer of the Company or person serving at the request of the
Company in an Authorized Capacity of or for Another Entity may also be subject
to liability arising out of such Proceeding or claim and in connection with such
Proceeding or claim seeks indemnification against the Company pursuant to an
agreement similar to this Agreement, the Indemnitee, together with such other
persons, will employ counsel to represent jointly the Indemnitee and such other
persons unless the Indemnitee determines that such joint representation


                                      -10-
<PAGE>   11

would be precluded under the applicable standards of professional conduct then
prevailing under the law of the State of Delaware, in which case the Indemnitee
will notify the Company (to the attention of the Secretary) thereof and will be
entitled to be represented by separate counsel.

                  15. EXPRESS NEGLIGENCE ACKNOWLEDGMENT. WITHOUT LIMITING OR
ENLARGING THE SCOPE OF THE INDEMNIFICATION OBLIGATIONS SET FORTH IN THIS
AGREEMENT, THE INDEMNITEE WILL BE ENTITLED TO INDEMNIFICATION HEREUNDER IN
ACCORDANCE WITH THE TERMS HEREOF, REGARDLESS OF WHETHER THE CLAIM GIVING RISE TO
SUCH INDEMNIFICATION OBLIGATION IS THE RESULT OF THE SOLE, CONCURRENT OR
COMPARATIVE NEGLIGENCE, OR STRICT LIABILITY, OF THE INDEMNITEE.

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

                                        VISTA ENERGY RESOURCES, INC.

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


                                        INDEMNITEE


                                        ----------------------------------------
                                           Name:
                                                --------------------------------



                                      -11-
<PAGE>   12
                                                                       Exhibit 1


                            INDEMNIFICATION STATEMENT


         1. This Indemnification Statement is submitted pursuant to the
Indemnification Agreement, dated as of __________, 199_ (the "Indemnification
Agreement"), between Vista Energy Resources, Inc., a Delaware corporation (the
Company"), and the undersigned.

         2. The undersigned is requesting indemnification in connection with a
Proceeding (as defined in the Indemnification Agreement) or claim in which the
undersigned was or is involved or is threatened to be made involved.

         3. With respect to all matters related to any such Proceeding or claim,
the undersigned believes that the undersigned is entitled to be indemnified
pursuant to the provisions of the Indemnification Agreement.

         4. Without limiting any other rights which the undersigned has or may
have, the undersigned is requesting indemnification against liabilities which
have or may arise out of _______________________________________________________
_______________________________________________________________________________.

         5. The undersigned has attached such documents supporting this request
as are reasonably available to the undersigned and are reasonably necessary to
determine whether and to what extent the undersigned is entitled to
indemnification under the Indemnification Agreement.


                                       -----------------------------------------

                                       Name:
                                            ------------------------------------

<PAGE>   13
                                                                       Exhibit 2


                                   UNDERTAKING


         1. This Undertaking is submitted pursuant to the Indemnification
Agreement, dated as of __________, 199_ (the "Indemnification Agreement"),
between Vista Energy Resources, Inc., a Delaware corporation (the "Company"),
and the undersigned.

         2. The undersigned is requesting advancement of certain costs, charges
and expenses (including attorneys' and others' fees) which the undersigned has
incurred or will incur in defending a Proceeding (as defined in the
Indemnification Agreement) or in connection with a claim for which the
undersigned may be entitled to indemnification pursuant to the Indemnification
Agreement.

         3. The undersigned hereby undertakes to repay this advancement of
expenses if it is ultimately determined that the undersigned is not entitled to
be indemnified by the Company under the Indemnification Agreement.

         4. The costs, charges and expenses for which advancement is requested
are, in general, all expenses related to _______________________________________
_____________________________________________________.


                                       -----------------------------------------

                                       Name:
                                            ------------------------------------