MIDLAND RESOURCES INC /TX/
10QSB, 1998-08-13
CRUDE PETROLEUM & NATURAL GAS
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<PAGE>
                         UNITED STATES

               SECURITIES AND EXCHANGE COMMISSION

                    Washington, D. C. 20549

                          FORM 10-QSB

      [X] QUARTERLY REPORT PURSUANT TO SECTION 13 OR 15(d)
             OF THE SECURITIES EXCHANGE ACT OF 1934

          For the quarterly period ended June 30, 1998

                 Commission file number 0-18836

                    MIDLAND RESOURCES, INC.
(EXACT NAME OF SMALL BUSINESS ISSUER AS SPECIFIED IN ITS CHARTER)

           Texas                               75-2286814
(STATE OR OTHER JURISDICTION                 (IRS EMPLOYER
     OF INCORPORATION)                    IDENTIFICATION NUMBER)


                                       
                 550 West Texas Ave., Ste. 700
                      Midland, Texas 79701
            (ADDRESS OF PRINCIPAL EXECUTIVE OFFICES)

                         (915) 570-5045
                  (ISSUER'S TELEPHONE NUMBER)

         616 F.M 1960 West, Ste. 600, Houston, Texas 77090
                        (FORMER ADDRESS)

     Check whether the issuer (1) filed all reports required to be filed by
Section 13 or 15(d) of the Securities Exchange Act of 1934 during the past 12
months (or for such shorter period that the registrant was required to file
such reports), and (2) has been subject to such filing requirements for the
past 90 days.   YES    X    NO
                      ---


             APPLICABLE ONLY TO CORPORATE ISSUERS:

     State the number of shares outstanding of each of the issuer's classes of
common stock as of the latest practicable date.

     Common Stock, $.001 par value: 4,467,699 shares outstanding at June 30,
1998
<PAGE>

                    MIDLAND RESOURCES, INC.


                       Table of Contents

<TABLE>
                                                             Page
                                                             ----
<S>                                                          <C>
PART I.  FINANCIAL INFORMATION


    Consolidated Balance Sheets as of June 30, 1998
    (Unaudited) and December 31, 1997                         3

    Unaudited Consolidated Statements of Operations
    for the three and six month periods ended
    June 30, 1998 and June 30, 1997                           5

    Unaudited Consolidated Statements of Cash Flows
    for the three and six month periods ended
    June 30, 1998 and June 30, 1997                           7

    Note to Unaudited Financial Statements                    9

    Management's Discussion and Analysis of Financial
    Condition and Results of Operations                      10


PART II.  OTHER INFORMATION                                  14


SIGNATURES                                                   15
</TABLE>

                            PAGE 2
<PAGE>

PART I - FINANCIAL INFORMATION

            MIDLAND RESOURCES, INC. AND SUBSIDIARIES
                  CONSOLIDATED BALANCE SHEETS

<TABLE>
                                                       June 30,     December 31,
                                                         1998           1997
                                                     ------------   ------------
                                                       Unaudited
<S>                                                  <C>            <C>
ASSETS

Current assets:
 Cash                                                $     56,673   $    150,890
 Accounts receivable:
  Oil and gas sales                                       417,062        670,093
  Related parties                                               -         60,822
  Sales of properties                                           -        563,757
  Property operations and other                           271,234        296,052
 Property and equipment held for sale                           -        200,000
 Reimbursable merger costs and other                      356,616         57,531
 Deferred tax asset                                        37,000         37,000
                                                     ------------   ------------
  Total current assets                                  1,138,585      2,036,145


Property and equipment, at cost, partially pledged:
 Oil and gas properties and equipment,
  using successful efforts method                      29,147,170     28,623,500
 Transportation equipment                                 198,810        215,749
 Computer equipment and software                          244,996        244,138
 Office furniture and equipment                            98,019         96,732
 Land, building and leasehold improvements                 15,347         15,347
 Wells in progress                                         82,933         15,233
 Less accumulated depreciation, depletion
  and amortization                                    (16,613,114)   (15,975,838)
                                                     ------------   ------------
  Property and equipment, net                          13,174,161     13,234,861

Other assets:
 Deferred tax asset                                     1,302,684      1,011,193
 Goodwill, net of amortization                            707,240        720,584
 Contracts and leases, net of amortization                188,422        199,116
 Note receivable                                          294,387        302,490
 Other                                                    101,553        116,094
                                                     ------------   ------------
Total assets                                         $ 16,907,032   $ 17,620,483
                                                     ------------   ------------
                                                     ------------   ------------
</TABLE>
                     THE ACCOMPANYING NOTE IS AN INTEGRAL PART
                     OF THE CONSOLIDATED FINANCIAL STATEMENTS.

                                    PAGE 3
<PAGE>

            MIDLAND RESOURCES, INC. AND SUBSIDIARIES
                  CONSOLIDATED BALANCE SHEETS

<TABLE>
                                                       June 30,      December 31,
                                                         1998            1997
                                                      -----------    ------------
                                                      Unaudited
<S>                                                   <C>            <C>
LIABILITIES AND STOCKHOLDERS' EQUITY

Current liabilities:
 Current portion of long-term debt                    $   900,000    $   583,481
 Accounts payable and accrued expenses                    726,529        981,202
                                                      -----------    -----------
  Total current liabilities                             1,626,529      1,564,683


Long-term debt                                          8,856,319      9,115,370
Payable for the purchase of subsidiary                    205,554        221,404
                                                      -----------    -----------
  Total liabilities                                    10,688,402     10,901,457

Stockholders' equity:
 Preferred stock, par value $0.01 per share; 
  20,000,000 shares authorized; none issued                     -              -
 Common stock, par value $0.001 per share; 
  80,000,000 shares authorized; 4,467,699 
  shares issued at June 30, 1998, and 
  4,463,499 shares at December 31, 1997                     4,468          4,463
 Additional paid in capital                             8,497,772      8,487,801
 Unearned compensation                                   (109,119)      (164,516)
 Retained earnings (deficit)                           (2,174,491)    (1,608,722)
                                                      -----------    -----------
  Total stockholders' equity                            6,218,630      6,719,026
                                                      -----------    -----------
Total liabilities and stockholders' equity            $16,907,032    $17,620,483
                                                      -----------    -----------
                                                      -----------    -----------
</TABLE>
                     THE ACCOMPANYING NOTE IS AN INTEGRAL PART
                     OF THE CONSOLIDATED FINANCIAL STATEMENTS.

                                    PAGE 4
<PAGE>

                     MIDLAND RESOURCES, INC. AND SUBSIDIARIES
                      CONSOLIDATED STATEMENTS OF OPERATIONS

<TABLE>
                                                      Three months ended June 30,
                                                      ---------------------------
                                                          1998           1997
                                                       ----------     ----------
                                                        Unaudited      Unaudited
<S>                                                    <C>            <C>
Operating revenue:
 Oil and gas sales                                     $1,027,332     $1,518,560
 Property operator fees                                    25,135         24,071
 Partnership income                                             -         99,007
 Other                                                      6,552          5,850
                                                       ----------     ----------
  Total operating revenue                               1,059,019      1,647,488
                                                       ----------     ----------
Operating costs and expenses:
 Oil and gas production                                   686,261        712,040
 Exploration costs, including exploratory dry holes         1,583        351,729
 Impairment losses                                              -        356,000
 Abandonments                                               5,722          -
 Depreciation, depletion and amortization                 362,396        319,452
 General and administrative                               342,822        483,334
                                                       ----------     ----------
  Total operating costs and expenses                    1,398,784      2,222,555
                                                       ----------     ----------
                                                         (339,765)      (575,067)
Other income and (expenses):
 Gain on sale of property and equipment                    10,048         25,426
 Interest and other income                                  6,741          8,199
 Interest expense                                        (211,488)      (198,195)
                                                       ----------     ----------
  Net other income and expenses                          (194,699)      (164,570)
                                                       ----------     ----------
Loss before income taxes                                 (534,464)      (739,637)

Deferred federal income tax benefit                      (181,743)      (251,416)
                                                       ----------     ----------
Net loss                                               $ (352,721)    $ (488,221)
                                                       ----------     ----------
                                                       ----------     ----------
Net loss per share:
 Basic                                                 $    (0.08)    $    (0.11)
                                                       ----------     ----------
                                                       ----------     ----------
 Diluted                                               $    (0.08)    $    (0.11)
                                                       ----------     ----------
                                                       ----------     ----------
Weighted average shares outstanding                     4,466,299      4,426,658
                                                       ----------     ----------
                                                       ----------     ----------
</TABLE>

                     THE ACCOMPANYING NOTE IS AN INTEGRAL PART
                     OF THE CONSOLIDATED FINANCIAL STATEMENTS.

                                    PAGE 5
<PAGE>


            MIDLAND RESOURCES, INC. AND SUBSIDIARIES
             CONSOLIDATED STATEMENTS OF OPERATIONS

<TABLE>
                                                        Six months ended June 30, 
                                                       ---------------------------
                                                           1998           1997
                                                        ---------      ---------
                                                        Unaudited      Unaudited
<S>                                                    <C>            <C>
Operating revenue:
 Oil and gas sales                                     $2,182,394     $3,346,815
 Property operator fees                                    51,855         51,150
 Partnership income                                             -         99,007
 Other                                                     15,497          8,655
                                                       ----------     ----------
  Total operating revenue                               2,249,746      3,505,627

Operating costs and expenses:
 Oil and gas production                                 1,416,724      1,449,529
 Exploration costs, including exploratory dry holes         4,709        360,284
 Abandonments                                              39,808              -
 Impairment losses                                              -        356,000
 Depreciation, depletion and amortization                 678,255        634,233
 General and administrative                               574,837        817,183
                                                       ----------     ----------
  Total operating costs and expenses                    2,714,333      3,617,229
                                                       ----------     ----------
                                                         (464,587)      (111,602)

Other income and (expenses):
 Gain on sale of property and equipment                    10,048        376,505
 Interest and other income                                 14,038         18,155
 Interest expense                                        (416,759)      (410,832)
                                                       ----------     ----------
  Net other income and expenses                          (392,673)       (16,172)
                                                       ----------     ----------
Loss before income taxes                                 (857,260)      (127,774)

Deferred federal income tax benefit                      (291,491)       (45,291)
                                                       ----------     ----------
Net loss                                               $ (565,769)    $  (82,483)
                                                       ----------     ----------
                                                       ----------     ----------
Net loss per share:
 Basic                                                 $    (0.13)    $    (0.02)
                                                       ----------     ----------
                                                       ----------     ----------
 Diluted                                               $    (0.13)    $    (0.02)
                                                       ----------     ----------
                                                       ----------     ----------
Weighted average shares outstanding                     4,464,822      4,416,345
                                                       ----------     ----------
                                                       ----------     ----------
</TABLE>
                     THE ACCOMPANYING NOTE IS AN INTEGRAL PART
                     OF THE CONSOLIDATED FINANCIAL STATEMENTS.

                                    PAGE 6
<PAGE>

            MIDLAND RESOURCES, INC. AND SUBSIDIARIES
             CONSOLIDATED STATEMENTS OF CASH FLOWS

<TABLE>
                                                      Three months ended June 30,
                                                      ---------------------------
                                                          1998          1997
                                                        ---------    -----------
                                                        Unaudited     Unaudited
<S>                                                     <C>          <C>
Cash flows from operating activities:
 Net loss                                               $(352,721)   $  (488,221)
 Deferred federal income tax benefit                     (181,743)      (251,416)
 Depreciation, depletion and amortization                 362,396        319,452
 Impairment losses                                              -        356,000
 Gain on sale of property and equipment                   (10,048)       (23,575)
 Non-cash stock based compensation                         27,699         73,969
 Decrease in accounts receivable                          314,556         26,101
 Increase in accounts payable                            (616,772)        98,816
 Increase (decrease) in other current assets               10,607         76,600
 Other                                                     15,665         12,764
                                                        ---------    -----------
 Net cash provided (used) by operating activities        (430,361)       200,490
                                                        ---------    -----------
Cash flows from investing activities:
 Proceeds from sales of property and equipment            239,048         23,575
 Additions to property and equipment                     (153,521)      (244,976)
 Summit stock tenders                                      (8,085)        (7,767)
 Business acquisition costs and other                    (241,238)             -
 Investment in limited partnership                              -       (963,619)
                                                        ---------    -----------
 Net cash used in investing activities                   (163,796)    (1,192,787)
                                                        ---------    -----------
Cash flows from financing activities:
 Exercise of warrants and options                           9,975         82,114
 Collection on note receivable                              3,778          3,489
 Long-term borrowings                                     520,000        650,000
 Principal payments on long-term debt                      (4,869)        (5,421)
 Drilling advances                                              -        457,121
 Reduction in drilling advances                                 -       (457,121)
                                                        ---------    -----------
 Net cash provided by financing activities                528,884        730,182
                                                        ---------    -----------
Net decrease in cash                                      (65,273)      (262,115)
Cash, beginning of the period                             121,946        342,495
                                                        ---------    -----------
Cash, end of period                                     $  56,673    $    80,380
                                                        ---------    -----------
                                                        ---------    -----------
</TABLE>
                     THE ACCOMPANYING NOTE IS AN INTEGRAL PART
                     OF THE CONSOLIDATED FINANCIAL STATEMENTS.

                                    PAGE 7
<PAGE>

            MIDLAND RESOURCES, INC. AND SUBSIDIARIES
             CONSOLIDATED STATEMENTS OF CASH FLOWS

<TABLE>
                                                       Six months ended June 30,
                                                       -------------------------
                                                          1998           1997
                                                        ---------     ---------
                                                        Unaudited     Unaudited
<S>                                                     <C>         <C>
Cash flows from operating activities:
 Net loss                                               $(565,769)  $   (82,483)
 Deferred federal income tax benefit                     (291,491)      (45,291)
 Depreciation, depletion and amortization                 678,255       634,233
 Impairment losses                                              -       356,000
 Gain on sale of property and equipment                   (10,048)     (374,654)
 Non-cash stock based compensation                         55,398       117,047
 Decrease in accounts receivable                          338,671       111,302
 Increase (decrease) in accounts payable                 (254,673)      711,451
(Increase) decrease in other current assets                (2,753)       20,277
 Other                                                     27,922        20,774
                                                        ---------   -----------
 Net cash provided (used) by operating activities         (24,488)    1,468,656
                                                        ---------   -----------
Cash flows from investing activities:
 Proceeds from sales of property and equipment            802,805     1,672,982
 Additions to property and equipment                     (622,515)   (1,225,268)
 Summit stock tenders                                     (15,850)     (104,792)
 Business acquisition cost and other                     (309,093)            -
 Investment in limited partnership                              -    (1,566,151)
 Cost reimbursement from limited partnership                    -       360,479
                                                        ---------   -----------
 Net cash used in investing activities                   (144,653)     (862,750)
                                                        ---------   -----------
Cash flows from financing activities:
 Exercise of warrants and options                           9,975       114,927
 Collection on note receivable                              7,481         6,909
 Long-term borrowings                                     720,000     1,056,250
 Principal payments on long-term debt                    (662,532)   (1,677,035)
 Drilling advances                                              -       457,121
 Reduction in drilling advances                                 -      (850,375)
                                                        ---------   -----------
 Net cash provided by (used in) financing activities       74,924      (892,203)
                                                        ---------   -----------
Net decrease in cash                                      (94,217)     (286,297)
Cash, beginning of the period                             150,890       366,677
                                                        ---------   -----------
Cash, end of period                                     $  56,673   $    80,380
                                                        ---------   -----------
                                                        ---------   -----------
</TABLE>
                     THE ACCOMPANYING NOTE IS AN INTEGRAL PART
                     OF THE CONSOLIDATED FINANCIAL STATEMENTS.

                                    PAGE 8
<PAGE>

            MIDLAND RESOURCES, INC. AND SUBSIDIARIES
           NOTES TO CONSOLIDATED FINANCIAL STATEMENTS

NOTE A. ORGANIZATION AND SIGNIFICANT ACCOUNTING POLICIES

  ORGANIZATION AND BASIS OF PRESENTATION

     Midland Resources, Inc. ("Company") was organized in 1990 with the
issuance of common stock and warrants in exchange for oil and gas partnership
interests.  The Company and its wholly owned subsidiaries are headquartered in
Midland, Texas.  The Company is involved in the acquisition, exploration,
development and production of oil and gas and owns producing properties and
undeveloped acreage in Texas, Colorado and Illinois. The majority of its
activities are centered in the Permian Basin of West Texas.  Midland Resources
Operating Company, Inc. ("MRO"), a wholly owned subsidiary, is in the business
of oil and gas property operations.  Summit Petroleum Corporation ("Summit") is
a wholly owned subsidiary engaged in oil and gas acquisition, exploration,
development and production.

PRINCIPLES OF CONSOLIDATION

  The accompanying consolidated balance sheets include the accounts of the
Company and its wholly owned subsidiaries.   All significant inter-company
accounts and transactions have been eliminated in consolidation.

  In the opinion of management, the accompanying unaudited consolidated
financial statements contain all adjustments necessary to present fairly the
financial position of the Company and its wholly owned subsidiaries as of June
30, 1998, the results of operations and cash flows for the three month and six
month periods ended June 30, 1998 and 1997.  The results of operations for the
periods presented are not necessarily indicative of the results to be expected
for a full year.  The accounting policies followed by the Company are set forth
in more detail in Note A of the "Notes to Consolidated Financial Statements" in
the Company's annual report on Form 10-KSB filed with the Securities and
Exchange Commission.  Certain information and footnote disclosures normally
included in financial statements prepared in accordance with generally accepted
accounting principles have been condensed or omitted in this Form 10-QSB
pursuant to the rules and regulations of the Securities and Exchange
Commission.  However, the disclosures herein are adequate to make the
information presented not misleading.  It is suggested that these financial
statements be read in conjunction with the financial statements and notes
thereto included  in the Form 10-KSB.

LOSS PER COMMON SHARE

  Net loss per common share is based on the weighted average number of shares
outstanding during the periods presented.  Common stock equivalents (options
and warrants) are excluded since their inclusion would have an antidilutive
effect on loss per share.

  The Financial Accounting Standards Board (FASB) has issued Statement of
Financial Accounting Standards No. 128 (SFAS 128), "Earnings Per Share" which
requires changes in the computation and reporting of earnings per share.  This
pronouncement, which becomes effective for periods ending after December 15,
1997, provides for the presentation of basic earnings per share, computed
without regard to options, warrants, and other stock equivalents, and diluted
earnings per share, which gives effect to these potential dilutive common
shares when they have a dilutive effect on earnings (loss) per share.

                                    PAGE 9
<PAGE>

                   MIDLAND RESOURCES, INC. AND SUBSIDIARIES
                   MANAGEMENT'S DISCUSSION AND ANALYSIS OF 
                FINANCIAL CONDITION AND RESULTS OF OPERATIONS

FORWARD-LOOKING STATEMENTS

Management's Discussion and Analysis of Financial Condition and Results of
Operations ("MDA") contains "forward-looking statements" within the meaning of
Section 27-A of the Securities Act of 1933, as amended (the Securities Act"),
and Section 218 of the Securities Exchange Act of 1934, as amended (the
"Exchange Act").  All statements other than statements of historical fact
included in MD&A, including statements regarding the Company's operating
strategy, plans, objectives and beliefs of management for future operations,
planned capital expenditures and acquisitions are forward-looking statements.
Although the Company believes that the assumptions upon which such forward-
looking statements are based are reasonable, it can give no assurance that such
assumptions will prove to be correct.

PLAN OF OPERATION

  During 1996 and 1997 the Company's exploration efforts consumed most of its
available resources.  While the Company believes its exploratory efforts have
identified possible future drilling opportunities, its ability to actively
pursue these efforts as well as to actively exploit existing developed
properties is dependent upon securing additional capital.

  Beginning in early 1997 the Company determined that it should explore
strategic alternatives to raising capital through sales of equity.  To assist
the Company it engaged in an investment banking firm.  During 1997 and
continuing into 1998 the Company considered various alternative transactions,
primarily consisting of sale of all or substantially all of its assets,
acquisitions of another smaller company, merging with a company of equal size
and merging with a larger company.  The company terminated its contract with
its investment banking firm in December 1997.

  On April 9, 1998, the Company announced it was pursuing a merger transaction
with Vista Resources Partners, L.P. (Vista), a privately held oil and gas 
exploration and production company located in Midland, Texas.  On May 22, 
1998, the Company entered into an agreement and plan of merger with Vista 
which provides for a business combination to be consummated, subject to 
stockholder approval.  If the transaction with Vista is not consummated, 
the Company expects to restrict its operations, including future development, 
to a level that its current operations can support, and continue to seek a 
strategic transaction as well as consider the sale of equity.

CAPITAL RESOURCES AND LIQUIDITY

The Company's initial capitalization was through the acquisition of 
interests of the seven public oil and gas income limited partnerships in 
exchange for common stock and warrants of the Company.  There were 2,265,522 
shares of common stock issued and, for each share of common stock issued, two 
warrants were issued entitling the holder to purchase one share of common 
stock at $2.50 and one share at $4.00 during the period of November 1990 to 
November 2002.  In October, 1995, the Company called for redemption its 
$2.50 warrants. Holders received a redemption payment of $0.05 per warrant 
for aggregate payments of $63,373, which was charged to additional paid in 
capital.  997,009 of the $2.50 warrants were exercised, resulting in net 
proceeds of approximately $1,831,000.  As of June 30, 1998, 11,428 of the 
$4.00 warrants had been exercised.

Historically, the Company's sources of  liquidity have been from both bank 
debt financing and operations.  However, low product prices in recent months, 
coupled with the costs of the Company's exploration program in 1996 and 1997 
have had severe adverse effects on the Company's liquidity.  The Company 

                                    PAGE 10
<PAGE>

presently has no readily available sources of additional capital resources 
and no commitments for capital expenditures, and intends to incur only those 
costs required to maintain necessary business operations and production from 
its properties.

In the first half of 1998, cash flow was a negative $94,217. Cash flows from 
operations was a negative $24,488 which includes the positive effects of a 
decrease in accounts receivable of $338,671 and the negative effects of a net 
decrease in accounts payable of $254,673.  Lower oil prices have had a 
significant adverse impact on operating cash flows.  Investing activities 
required the use of $144,653 in cash due primarily to merger costs of 
$296,332 in connection with the proposed Vista transaction discussed above, 
partially offset by proceeds from sales of properties in excess of capital 
additions. Financing activities resulted in a net increase in cash of $74,924 
due primarily to  bank borrowings of $720,000 which were used to fund capital 
expenditures and merger costs.  Repayments of bank debt of $651,615 were 
funded primarily from the proceeds of a December, 1997 property sale.

At June 30, 1998, the Company had negative working capital of approximately 
$488,000 compared to positive working capital of approximately $471,000 at 
December 31, 1997, for a net decrease of $959,000.  This is due primarily to 
the adverse impact on revenue of  lower oil prices during the first half of 
1998, and an increase in current debt maturities under the Company's 
revolving credit agreement with its bank resulting from a reduction in 
borrowing base which was also due to current low oil prices.

The Company has a revolving credit agreement with Compass Bank (Bank) which 
provides for a credit facility of $30,000,000 and an initial borrowing base 
of $10,500,000.  Effective June 1, 1998, the borrowing base was reduced to 
$9,800,000 with scheduled monthly reductions of $80,000 per month beginning 
August 1, 1998.  The borrowing base is subject to redetermination in November 
and May of each year.  Amounts borrowed under this agreement are 
collateralized by a first lien on substantially all of the Company's oil and 
gas properties. Interest under this agreement is payable monthly  at an 
annual rate which, at the Company's option, is equal to (a) the Bank's index 
lending rate (8.5% at June 30, 1998), or (b) the London Interbank Offered 
Rate (LIBOR), plus 2.5%. In addition, a commitment fee equal to 1/2% per 
annum on the unused portion of the borrowing base is required.  This 
agreement also requires that the Company maintain certain financial ratios 
and generally restricts the Company's ability to incur debt, sell assets, 
materially change the nature of the Company's business structure or pay 
dividends.  As of June 30, 1998, the balance due under this agreement was 
$9,720,000 and at August 13, 1998 was $9,640,000.

The prices of crude oil have fluctuated significantly in recent years as well 
as in recent months.  As of June 30, 1997, the Company was receiving $18.60 
per bbl as compared to $25.00 at January 1, 1997. At June 30, 1998 the 
Company was receiving approximately $12.00 per bbl as compared to $16.52 at 
January 1, 1998. Fluctuations in price have a significant impact on the 
Company's financial condition and liquidity.

RESULTS OF OPERATIONS - THREE MONTHS ENDED JUNE 30, 1998 AND 1997

Net loss decreased from a loss of $488,221 for the three months ended June 30,
1997, to a net loss of $352,721 for the same period in 1998, a decrease of
$135,500.  Individual categories of income and expense are discussed below.

Oil and gas sales decreased from $1,518,560 in the second quarter of 1997 to
$1,027,332 in the same period of 1998.  This decrease of $491,228 or 32%
resulted from decreased oil and gas prices and decreased gas production. Oil
and gas production quantities were 46,923 bbls and 216,636 mcf for the second
quarter of 1998 and 47,366 bbls and 264,909 mcf  in 1997, a decrease of 443
bbls or 1% and a decrease of 48,273 mcf, or 18%.  Average gas prices decreased
from $2.25 per mcf in 1997 to $1.91 per mcf in 1998, while average oil prices
decreased from $19.38 per bbl in 1997 to $13.10 per bbl in 1998.

In the second quarter of 1997, the Company's share of net income from a limited
partnership was $99,007, including $115,875 oil revenue from 6,195 bbls of
production.  There was no similar item in 1998.

                                    PAGE 11
<PAGE>

Production costs decreased from $712,040 in the second quarter of 1997 to
$686,261 for the same period of 1998, a decrease of $25,779, or 4%.  This
decrease was attributable to cost reduction measures as well as to the sale in
December 1997 of operated properties in Colorado and other non-operated
property interests.

In the second quarter of 1997, the Company incurred exploratory dry hole costs
of $332,194.  There was no similar item in the second quarter of 1998.

General and administrative expenses ("G&A") were $342,822 in the second quarter
of 1998 and $483,334 in the second quarter of 1997, a decrease of $140,512, or
29%.  This was due primarily to continued cost curtailment measures which began
in the fourth quarter of 1997.

Depreciation, depletion and amortization ("DD&A") based on production and 
other methods increased from $319,452 in the second quarter of 1997 to 
$362,396 in the same period of 1998, an increase of $42,944 or 12%, due 
primarily to lower reserve estimates on most properties. Lower product prices 
had a significant adverse impact on the determination of reserve quantity 
estimates.

In the second quarter of 1997, the Company provided for property impairment
losses of $356,000 on two of its wells.  There was no similar item in the
second quarter of 1998.

RESULTS OF OPERATIONS-SIX MONTHS ENDED JUNE 30, 1998 AND 1997

Net loss increased from $82,483 in the first half of 1997 to $565,769 in the
first half of 1998.  Individual categories of income and expenses are discussed
below.

Oil and gas sales decreased from $3,346,815 in the first six months of 1997 to
$2,182,394 in the same period of 1998.  This decrease of $1,164,421 or 35%
resulted from decreased oil and gas prices and gas production.  Oil and gas
production quantities were 94,791 bbls and 515,982 mcf in 1997 and 94,714 bbls
and 435,522 mcf in 1998, a decrease of 77 bbls and a decrease of 80,460 mcf or
16 %.  Average gas prices decreased from $2.62 per mcf in 1997 to $2.01 per mcf
in 1998, while average oil prices decreased from $20.91 per bbl in 1997 to
$13.78 per bbl in 1998.

In the first six months of 1997, the Company's share of net income from an oil
and gas limited partnership was $99,007 which included oil revenue of $115,875
from 6,195 bbls of production.  There was no similar item in 1998.

Production costs decreased from $1,449,529 in the first six months of 1997 to
$1,416,724 for the same period of 1998, an decrease of $32,805 or 2%.

In the first half of 1997, exploration costs were $360,284, which included
$332,194 in exploratory dry hole costs. In the first half of 1998, exploration
costs were $4,709.

G&A decreased from $817,183 in the first six months of 1997 to $574,837 in the
same period of 1998, a decrease of $242,346 or 42%.  These totals included  non-
cash stock based compensation charges of $117,047 in 1997 and $55,398 in 1998.
Other reductions resulted from cost curtailment measures instituted in the
fourth quarter of 1997.

                                    PAGE 12
<PAGE>

DD&A based on production and other methods increased from $634,233 in the first
six months of 1997 to $678,255 in the same period of 1998, an increase of
$44,022 or 7%, due primarily to lower reserve quantity estimates.

At June 30, 1997, the Company provided for impairment losses on its oil and gas
properties of $356,000.  There was no similar item in 1998.

In the first half of 1997, the Company reported gains from sales of property of
$376,505 of which $349,079 was from the sale of the Redfish Bay property in
February of 1997.  The gain from asset sales in the first half of 1998 was
$10,048.



                                    PAGE 13
<PAGE>

PART II - OTHER INFORMATION

Item 1.  LEGAL PROCEEDINGS

            None.

Item 2.  CHANGES IN SECURITIES

            None.

Item 3.  DEFAULTS UPON SENIOR SECURITIES

            None.

Item 4.  SUBMISSION OF MATTERS TO A VOTE OF SECURITY HOLDERS

            None

Item 5.  OTHER INFORMATION

The Company entered into an Agreement and Plan of Merger dated May 22, 1998, 
as it may be amended, supplemented or modified from time to time (the "Merger 
Agreement") with Vista Resources Partners, L.P., a Texas limited partnership, 
Vista Resources, Inc., a Delaware corporation and a direct wholly owned 
subsidiary of the Vista Partnership ("Vista"), and Midland Merger Co., a 
Texas corporation and direct wholly owned subsidiary of Vista ("Merger Sub"), 
pursuant to which Merger Sub will be merged into the Company. Consummation of 
this merger is subject to approval of the Company's stockholders.

Concurrent with the execution of this Merger Agreement, the Company and its 
former president, Deas H. Warley III, entered into an agreement in settlement 
of Mr. Warley's employment contract. This agreement generally provides that 
(i) from March 27, 1998, through either the consummation or termination of the
Merger Agreement, the Company will pay Mr. Warley the sum of $11,390 per month;
(ii) on the effective date of the merger, the Company will pay Mr. Warley the 
sum of $1,300,000 (reduced by a payment of $100,000 to Marilyn D. Wade), 
payable in monthly installments of $20,000 per month over 60 months, provided 
that, after one year, either the Company or Mr. Warley may elect to have such 
amount paid as a lump sum (using a discount factor of 6%); (iii) Mr. Warley's 
stock options for 15,000 shares shall expire on the 120th day following the 
effective date of the merger; (iv) Mr. Warley agrees to support the merger 
and take or refrain from taking actions as contemplated by the Merger 
Agreement; and (v) the Company and Mr. Warley mutually release one another 
from all claims.

Effective June 1, 1998, the Company's wholly owned operating subsidiary, 
Midland Resources Operating Co., Inc., and Vista entered into a Contract 
Operating Agreement which generally provides that Vista will provide various 
contract operating services for the Company with respect to its oil and gas 
properties, including engineering, geological, land, legal and other property 
operating services, at a rate of $400 per day. This agreement is in effect 
through October 31, 1998 and on month-to-month basis thereafter unless 
terminated by either party. General and administrative services are also 
furnished at agreed upon rates.

Item 6.  EXHIBITS AND REPORTS ON FORM 8-K

          a:  Exhibits:  

<TABLE>
<S>              <C>    <C>
                  2.1   Agreement and Plan of Merger, dated May 22, 1998, 
                        between Midland Resources, Inc. and Vista Resources 
                        Partners, L.P.

                 10.1   Contract Operating Agreement, effective June 1, 1998 
                        between Vista Resources, Inc. and Midland Resources 
                        Operating Company, Inc.

                 10.2   Warley Settlement Agreement dated May 22, 1998, 
                        between Midland Resources, Inc. and Deas H. Warley III.

                 27     Article 5 Financial Data Schedule for second quarter 
                        10-QSB (only filed electronically)
</TABLE>

          b:  None


                                    PAGE 14
<PAGE>


                                    SIGNATURES

     In accordance with the requirements of the Exchange Act, the Registrant
caused this report to be signed on its behalf by the undersigned, hereunto duly
authorized.



                                   MIDLAND RESOURCES, INC.
                                   (Registrant)






Date: August 13, 1998            By:  /s/ Robert R. Donnelly
                                      ----------------------------------------
                                      Robert R. Donnelly, President


     Pursuant to the requirements of the Securities and Exchange Act of 1934,
this report has been signed below by the following person on behalf of the
Registrant and in the capacity and on the date indicated.






Date: August 13, 1998            By:  /s/ Howard E. Ehler
                                      ----------------------------------------
                                      Howard E. Ehler, Chief Financial Officer

                                        PAGE 15

<PAGE>

APPENDIX A
================================================================================
 
                             AGREEMENT AND PLAN OF MERGER
 
                                     AMONG
 
                        VISTA RESOURCES PARTNERS, L.P.,
 
                            MIDLAND RESOURCES, INC.,
 
                         VISTA ENERGY RESOURCES, INC.,
 
                                      AND
 
                               MIDLAND MERGER CO.
 
                            DATED AS OF MAY 22, 1998
 
================================================================================


                                       A-1
<PAGE>

                               TABLE OF CONTENTS

<TABLE>
<CAPTION>
                                                                       PAGE NO.
                                                                       --------
<S>   <C>   <C>                                                        <C>
ARTICLE 1
 
DEFINITIONS
1.1   Defined Terms.....................................................   A-7
1.2   References and Titles.............................................  A-13
 
ARTICLE 2
 
THE MERGER AND EXCHANGES
2.1   The Midland Merger................................................   A-14
2.2   Effect of the Midland Merger......................................   A-14
2.3   Certificates of Incorporation of Newco, Midland and Newco Sub.....   A-14
2.4   Bylaws............................................................   A-14
2.5   Directors.........................................................   A-14
2.6   Officers..........................................................   A-15
2.7   Effect on Securities..............................................   A-15
2.8   Vista Exchange Agreements.........................................   A-16
2.9   Adjustments.......................................................   A-17
2.10  Exchange of Certificates..........................................   A-17
2.11  Closing...........................................................   A-20
2.12  Effective Time of the Merger......................................   A-20
2.13  Shareholder Approvals Obtained....................................   A-20

ARTICLE 3
 
REPRESENTATIONS AND WARRANTIES
3.1   Representations and Warranties of Midland.........................   A-20
      (a)   Organization, Standing and Power............................   A-20
      (b)   Capital Structure...........................................   A-21
      (c)   Authority; No Violations; Consents and Approvals............   A-22
      (d)   SEC Documents...............................................   A-23
      (e)   Information Supplied........................................   A-23
      (f)   Absence of Certain Changes or Events........................   A-24
      (g)   No Undisclosed Material Liabilities.........................   A-24
      (h)   No Default..................................................   A-24
      (i)   Compliance with Applicable Laws.............................   A-24
      (j)   Litigation..................................................   A-25
      (k)   Taxes.......................................................   A-25
      (l)   Employee Benefit Matters....................................   A-27
      (m)   Labor Matters...............................................   A-28
      (n)   Intangible Property.........................................   A-29
      (o)   Environmental Matters.......................................   A-29
      (p)   Insurance...................................................   A-31
      (q)   Absence of Certain Changes or Events........................   A-31
      (r)   Governmental Regulation.....................................   A-32
      (s)   No Restrictions.............................................   A-32
      (t)   Audits and Settlements......................................   A-33
      (u)   Employment Contracts and Benefits...........................   A-33
      (v)   Accounts Receivable.........................................   A-33
      (w)   Title to Assets.............................................   A-33
      (x)   Midland Engineering Report..................................   A-33
</TABLE>


                                       A-2
<PAGE>

<TABLE>
<CAPTION>
                                                                       PAGE NO.
                                                                       --------
<S>   <C>   <C>                                                        <C>
      (y)   Oil and Gas Operations......................................   A-34
      (z)   Hydrocarbon Sales and Purchase Agreements...................   A-34
      (aa)  Financial and Commodity Hedging.............................   A-35
      (bb)  Committed Capital Expenditures..............................   A-35
      (cc)  Business Relations..........................................   A-35
      (dd)  Books and Records...........................................   A-35
      (ee)  Brokers.....................................................   A-35
      (ff)  Vote Required...............................................   A-36
      (gg)  Disclosure and Investigation................................   A-36
      (hh)  Fairness Opinion............................................   A-36
3.2   Representations and Warranties of Vista...........................   A-36
      (a)   Organization, Standing and Power............................   A-36
      (b)   Capital Structure...........................................   A-36
      (c)   Authority; No Violations; Consents and Approvals............   A-37
      (d)   Financial Statements and Material Agreements................   A-38
      (e)   Information Supplied........................................   A-38
      (f)   Absence of Certain Changes or Events........................   A-38
      (g)   No Undisclosed Material Liabilities.........................   A-38
      (h)   No Default..................................................   A-39
      (i)   Compliance with Applicable Laws.............................   A-39
      (j)   Litigation..................................................   A-39
      (k)   Taxes.......................................................   A-39
      (l)   Employee Benefit Matters....................................   A-41
      (m)   Labor Matters...............................................   A-42
      (n)   Intangible Property.........................................   A-43
      (o)   Environmental Matters.......................................   A-43
      (p)   Insurance...................................................   A-44
      (q)   Absence of Certain Changes or Events........................   A-44
      (r)   Governmental Regulation.....................................   A-45
      (s)   No Restrictions.............................................   A-45
      (t)   Audits and Settlements......................................   A-46
      (u)   Employment Contracts and Benefits...........................   A-46
      (v)   Accounts Receivable.........................................   A-46
      (w)   Title to Assets.............................................   A-46
      (x)   Vista Engineering Report....................................   A-46
      (y)   Oil and Gas Operations......................................   A-47
      (z)   Hydrocarbon Sales and Purchase Agreements...................   A-47
      (aa)  Financial and Commodity Hedging.............................   A-48
      (bb)  Committed Capital Expenditures..............................   A-48
      (cc)  Business Relations..........................................   A-48
      (dd)  Books and Records...........................................   A-48
      (ee)  Brokers.....................................................   A-49
      (ff)  Disclosure and Investigation................................   A-49
3.3   Representations and Warranties of Newco and Merger Sub............   A-49
      (a)   Organization, Standing and Corporate Power..................   A-49
      (b)   Capital Structure...........................................   A-49
      (c)   Authority; No Violations; Consents and Approvals............   A-50
      (d)   No Prior Activities.........................................   A-50
</TABLE>


                                       A-3
<PAGE>

<TABLE>
<CAPTION>
                                                                       PAGE NO.
                                                                       --------
<S>   <C>   <C>                                                        <C>
ARTICLE 4

COVENANTS
4.1   Conduct of Business by Vista and Midland Pending Closing..........   A-50
4.2   Access to Assets, Personnel, and Information......................   A-53
4.3   No Solicitation by Midland........................................   A-55
4.4   No Solicitation by Vista..........................................   A-56
4.5   Midland Shareholders Meeting......................................   A-56
4.6   S-4 and Proxy Statement...........................................   A-57
4.7   Stock Exchange Listing............................................   A-58
4.8   Additional Arrangements...........................................   A-58
4.9   Agreements of Rule 145 Affiliates.................................   A-58
4.10  Public Announcements..............................................   A-58
4.11  Notification of Certain Matters...................................   A-59
4.12  Payment of Expenses...............................................   A-59
4.13  Indemnification...................................................   A-59
4.14  Indemnification Agreements........................................   A-60
4.15  Registration of Shares to be Issued Pursuant to Stock Options.....   A-60
4.16  Registration Rights Agreement.....................................   A-60
4.17  Resignations of Officers and Directors of Midland.................   A-61
4.18  Newco Long-Term Incentive Plan....................................   A-61
4.19  Midland Option Exercise Agreements................................   A-61
4.20  Transactions with Affiliates......................................   A-61

ARTICLE 5
 
CONDITIONS
5.1   Conditions to Each Party's Obligation to Effect the Merger........   A-61
      (a)   Shareholder Approval........................................   A-61
      (b)   Fairness Opinion............................................   A-61
      (c)   Tax Opinion.................................................   A-61
      (d)   Exchange Listing............................................   A-61
      (e)   Other Approvals.............................................   A-61
      (f)   Securities Law Matters......................................   A-62
      (g)   No Injunctions or Restraints................................   A-62
5.2   Conditions of Obligations of Vista, Newco, and Merger Sub.........   A-62
      (a)   Representations and Warranties..............................   A-62
      (b)   Performance of Covenants and Agreements.....................   A-62
      (c)   Comfort Letter..............................................   A-62
      (d)   Dissenters' Rights..........................................   A-62
      (e)   Legal Opinion...............................................   A-62
      (f)   No Adverse Change...........................................   A-62
      (g)   Midland Option Exercise Agreements..........................   A-63
5.3   Conditions of Obligations of Midland..............................   A-63
      (a)   Representations and Warranties..............................   A-63
      (b)   Performance of Covenants and Agreements.....................   A-63
      (c)   Legal Opinion...............................................   A-63
      (d)   Comfort Letter..............................................   A-63
      (e)   No Adverse Change...........................................   A-63
      (f)   Exchange Agreements.........................................   A-63
</TABLE>


                                       A-4
<PAGE>

<TABLE>
<CAPTION>
                                                                       PAGE NO.
                                                                       --------
<S>   <C>   <C>                                                        <C>
ARTICLE 6
 
TERMINATION
6.1   Termination Rights................................................   A-64
6.2   Effect of Termination.............................................   A-65
 
ARTICLE 7
 
MISCELLANEOUS
7.1   Amendment.........................................................   A-65
7.2   Extension; Waiver.................................................   A-65
7.3   Nonsurvival of Representations, Warranties, Covenants, and
      Agreements........................................................   A-65
7.4   Notices...........................................................   A-65
7.5   Counterparts......................................................   A-66
7.6   Severability......................................................   A-66
7.7   Entire Agreement; No Third Party Beneficiaries....................   A-66
7.8   Applicable Law....................................................   A-66
7.9   No Remedy in Certain Circumstances................................   A-66
7.10  Enforcement of Agreement..........................................   A-66
7.11  Assignment........................................................   A-67
7.12  Waivers...........................................................   A-67
7.13  Certain Provisions Inapplicable...................................   A-67
7.14  Termination of Letter of Intent and Confidentiality Agreement.....   A-67
EXHIBITS:
  Exhibit A          -- Form of Midland Exchange Agreement
  Exhibit B          -- Form of Midland Voting Agreement
  Exhibit C          -- Form of Newco Warrant
  Exhibit D          -- Form of Midland Option Exercise Agreement
  Exhibit E          -- Form of Vista Exchange Agreement
  Exhibit 3.3(a)     -- Newco Certificate of Incorporation and Bylaws
  Exhibit 4.9(a)     -- Form of Vista Affiliate's Agreement
  Exhibit 4.9(b)     -- Form of Midland Affiliate's Agreement
                     -- Form of Indemnification Agreement for Vista Officers and
  Exhibit 4.14(a)       Directors
                     -- Form of Indemnification Agreement for Midland Officers
  Exhibit 4.14(b)       and Directors
  Exhibit 4.16(a)    -- Form of Vista Registration Rights Agreement
  Exhibit 4.16(b)    -- Form of Midland Registration Rights Agreement
  Exhibit 4.17(a)    -- Form of Termination Agreement for Howard E. Ehler
  Exhibit 4.17(b)    -- Form of Termination Agreement for Marilyn D. Wade
  Exhibit 4.18       -- Form of Newco Long-Term Incentive Plan
  Exhibit 5.2(e)(i)  -- Midland Legal Opinion
  Exhibit            -- Midland 10b-5 Letter
     5.2(e)(ii)
  Exhibit 5.3(c)(i)  -- Vista Legal Opinion
  Exhibit            -- Vista 10b-5 Letter
     5.3(c)(ii)


DISCLOSURE SCHEDULES:
  Midland Disclosure Schedule
  Vista Disclosure Schedule
</TABLE>


                                       A-5
<PAGE>

                          AGREEMENT AND PLAN OF MERGER

     THIS AGREEMENT AND PLAN OF MERGER (this "Agreement") is entered into,
effective as of May 22, 1998, by and among Vista Resources Partners, L.P., a
Texas limited partnership ("Vista"), Midland Resources, Inc., a Texas
corporation ("Midland"), Vista Energy Resources, Inc., a Delaware corporation
and a direct wholly-owned subsidiary of Vista ("Newco"), and Midland Merger Co.,
a Texas corporation and a direct wholly-owned subsidiary of Newco ("Merger
Sub").
 
                                    RECITALS
 
     A. Vista and Midland have determined to engage in a strategic business
combination.
 
     B. In furtherance thereof, Vista Resources I, Inc., the sole general
partner of Vista (the "General Partner"), has approved this Agreement and the
exchange (the "Vista GP Exchange") of shares of Newco common stock, $.01 par
value per share ("Newco Common Stock"), and warrants that are exercisable for
shares of Newco Common Stock ("Newco Warrants") for all of the outstanding
shares of common stock, $.01 par value per share, of the General Partner (the
"GP Common Stock") and the exchange (the "Vista LP Exchange" and, together with
the Vista GP Exchange, the "Vista Exchange") of shares of Newco Common Stock and
Newco Warrants for all of the outstanding Partnership Interests (as hereinafter
defined).
 
     C. Contemporaneously with the execution and delivery of this Agreement,
Newco and each holder of a Midland Exchange Stock Option has entered into a
Midland Exchange Agreement pursuant to which such holder has agreed to exchange
(the "Midland Exchange") his Midland Exchange Stock Options for Newco Warrants.
 
     D. In furtherance thereof, the respective Boards of Directors of Merger Sub
and Midland have approved this Agreement and the merger of Merger Sub with and
into Midland, with Midland being the surviving corporation (the "Midland
Merger").
 
     E. In furtherance thereof, the Board of Directors of Newco has approved the
contribution of the Partnership Interests received by it pursuant to the Vista
LP Exchange to Vista LLC, a Delaware limited liability company and a direct
wholly-owned subsidiary of Newco ("Newco LLC"), effective immediately after the
Midland Merger and the Vista Exchange (the "Newco Contribution").
 
     F. The respective Boards of Directors of Newco, Merger Sub and Midland have
determined that it is in the best interests of their respective shareholders or
stockholders (hereinafter referred to as "shareholders"), and the General
Partner has determined that it is in the best interests of the limited partners
of Vista, for the Midland Merger and the Vista Exchange to be effected upon the
terms and subject to the conditions of this Agreement.
 
     G. For federal income tax purposes, it is intended that (a) the Vista
Exchange shall qualify as a transfer within the meaning of Section 351 of the
Internal Revenue Code of 1986, as amended (the "Code"), (b) the Midland Merger
and the Midland Exchange shall qualify as a reorganization within the meaning of
Section 368(a) of the Code, and (c) this Agreement be, and is adopted as, a plan
of reorganization within the meaning of Treasury Regulation Section 1.368-1(c).
 
     H. Contemporaneously with the execution and delivery of this Agreement,
Newco and each of Deas H. Warley III, Howard E. Ehler, Robert R. Donnelly, Sam
R. Brock, Wayne M. Whitaker, John Q. Adams and Darrell M. Dillard have entered
into separate Midland Voting Agreements (as hereinafter defined).
 
     I. Vista, Newco, Merger Sub and Midland desire to make certain
representations, warranties, covenants and agreements in connection with the
Midland Merger and the Vista Exchange and also to prescribe various conditions
to the Midland Merger and the Vista Exchange.
 
     NOW, THEREFORE, for and in consideration of the mutual covenants and
agreements set forth in this Agreement and for other good and valuable
consideration, the receipt and sufficiency of which are hereby acknowledged, the
parties to this Agreement hereby agree as follows:
 

                                       A-6
<PAGE>
 
                                   ARTICLE 1
 
                                  DEFINITIONS
 
     1.1 DEFINED TERMS. As used in this Agreement, each of the following terms
has the meaning given in this Section or in the Sections referred to below:
 
     "Affiliate" means, with respect to any Person, each other Person that
directly or indirectly (through one or more intermediaries or otherwise)
controls, is controlled by, or is under common control with such Person. For
purposes of this definition and this Agreement, the term "control" (and
correlative terms) means the power, whether by contract, equity ownership or
otherwise, to direct the policies or management of a Person.
 
     "Affiliate Agreement" has the meaning specified in Section 4.9.
 
     "Agreement" means this Agreement and Plan of Merger, as amended,
supplemented, or modified from time to time.
 
     "Agreement of Limited Partnership" means the Agreement of Limited
Partnership for Vista dated as of September 26, 1995, by and among the General
Partner and the persons who have executed such agreement as limited partners.
 
     "AMEX" means the American Stock Exchange or any successor thereto.
 
     "Audited Financial Statements" has the meaning specified in Section 3.2(d).
 
     "Closing" means the closing of the Midland Merger, the Midland Exchange and
the Vista Exchange and the consummation of the other transactions contemplated
by this Agreement.
 
     "Closing Date" means the date on which the Closing occurs, which date shall
be the first business day following the day on which all of the conditions
provided for in Article 5 have been satisfied or waived as provided therein (or
such later date as is mutually agreed upon by the parties).
 
     "Code" means the Internal Revenue Code of 1986, as amended.
 
     "Defensible Title" means good and defensible right, title, and interest
that is (a) evidenced by an instrument or instruments filed of record in
accordance with the conveyance and recording laws of the applicable jurisdiction
to the extent necessary to prevail against competing claims of bona fide
purchasers for value without notice and (b) subject to Permitted Encumbrances,
free and clear of all Liens, claims, infringements, burdens, or other defects.
 
     "DGCL" means the Delaware General Corporation Law, as amended.
 
     "Effective Time" has the meaning specified in Section 2.12.
 
     "Environmental Laws" has the meaning specified in Section 3.1(o)(i).
 
     "ERISA" means the Employee Retirement Income Security Act of 1974, as
amended.
 
     "Excess Shares" has the meaning specified in Section 2.10(e)(ii).
 
     "Exchange Act" means the Securities Exchange Act of 1934, as amended.
 
     "Exchange Agent" shall mean such agent as is reasonably satisfactory to
Newco and Midland.
 
     "Exchange Fund" has the meaning specified in Section 2.10(a).
 
     "Financial Statements" has the meaning specified in Section 3.2(d).
 
     "First Union" has the meaning specified in Section 3.1(ee).
 
     "Fully Diluted Basis" means as of the date of the calculation thereof the
sum of (a) the number of shares of Newco Common Stock then issued and
outstanding immediately after the Effective Time, plus (b) the number of shares
of Newco Common Stock, if any, issued after the Effective Time as a result of
the exercise of any Midland Stock Options (other than Midland Exchange Stock
Options), plus (c) the number of shares
 

                                       A-7
<PAGE>
 
of Newco Common Stock issuable, whether at such time or upon the passage of time
or the occurrence of future events, upon exercise, conversion or exchange of all
Midland Exercisable Warrants outstanding as of the close of business on the
trading day immediately preceding the second business day immediately prior to
the Closing Date.
 
     "GAAP" has the meaning specified in Section 3.1(d).
 
     "General Partner" means has the meaning specified in the Recitals hereto.
 
     "Governmental Action" means any authorization, application, approval,
consent, exemption. filing, license, notice, registration, permit, or other
requirement of, to, or with any Governmental Entity.
 
     "Governmental Entity" has the meaning specified in Section 3.1(c)(iii).
 
     "GP Certificate" means a certificate representing shares of GP Common
Stock.
 
     "GP Common Stock" has the meaning specified in the Recitals hereto.
 
     "Hazardous Materials" has the meaning specified in Section 3.1(o)(ii).
 
     "Hydrocarbon Agreement" means any of the Hydrocarbon Sales Agreements, the
Hydrocarbon Purchase Agreements, and the Hydrocarbon Support Agreements.
 
     "Hydrocarbon Purchase Agreement" means any material sales agreement,
purchase contract, or marketing agreement that is currently in effect and under
which Midland or any of its Subsidiaries (or Vista or Vista Sub, as applicable)
is a buyer of Hydrocarbons for resale (other than purchase agreements entered
into in the ordinary course of business with a term of three months or less,
terminable without penalty on 30 days' notice or less, which provide for a price
not greater than the market value price that would be paid pursuant to an
arm's-length contract for the same term with an unaffiliated third-party seller,
and which do not obligate the purchaser to take any specified quantity of
Hydrocarbons or to pay for any deficiencies in quantities of Hydrocarbons not
taken).
 
     "Hydrocarbon Sales Agreement" means any material sales agreement, purchase
contract, or marketing agreement that is currently in effect and under which
Midland or any of its Subsidiaries (or Vista or Vista Sub, as applicable) is a
seller of Hydrocarbons (other than "spot" sales agreements entered into in the
ordinary course of business with a term of three months or less, terminable
without penalty on 30 days' notice or less, and which provide for a price not
less than the market value price that would be received pursuant to an
arm's-length contract for the same term with an unaffiliated third party
purchaser).
 
     "Hydrocarbon Support Agreement" means any gathering, transportation,
treatment, compression, processing, or similar agreement that is currently in
effect and to which Midland or any of its Subsidiaries (or Vista or Vista Sub,
as applicable) is a party (other than gathering, transportation, treatment,
compression, processing, and similar agreements that have been entered into in
the ordinary course of business and which contain market value prices and terms
of the type found in gathering, transportation, treatment, compression,
processing, and similar agreements entered into between unaffiliated parties in
arm's length transactions).
 
     "Hydrocarbons" means oil, condensate, gas, casinghead gas, and other liquid
or gaseous hydrocarbons.
 
     "Indemnification Agreement" has the meaning specified in Section 4.14.
 
     "IRS" means the Internal Revenue Service.
 
     "Lien" means any lien, trust, mortgage, security interest, pledge, deposit,
production payment, restriction, burden, claim, charge, detriment, option,
encumbrance, voting agreement, preemptive right, shareholder agreement, rights
of a vendor under any title retention or conditional sale agreement, or lease or
other arrangement substantially equivalent to any of the foregoing.
 
     "Material Adverse Change" has the meaning specified in Section 3.1(a).
 
     "Material Adverse Effect" has the meaning specified in Section 3.1(a).
 

                                       A-8
<PAGE>
 
     "Merger Sub" means Midland Merger Co., a Texas corporation and a direct
wholly-owned subsidiary of Newco.
 
     "Midland" means Midland Resources, Inc., a Texas corporation.
 
     "Midland Acquisition Proposal" has the meaning specified in Section 4.3(b).
 
     "Midland Articles of Merger" has the meaning specified in Section 2.12.
 
     "Midland Benefit Program or Agreement" has the meaning specified in 
Section 3.1(l).
 
     "Midland Certificate" means a certificate representing shares of Midland
Common Stock.
 
     "Midland Common Stock" means the common stock, par value $.001 per share,
of Midland.
 
     "Midland Common Stock Warrant" means all Midland Stock Equivalents other
than the Midland Stock Options and Midland Warrants.
 
     "Midland Conversion Number" means one.
 
     "Midland Engineering Report" means the oil and gas reserve engineering
report concerning the Oil and Gas Interests of Midland as of January 1, 1998
prepared by Williamson Petroleum Consultants, Inc., and provided to Vista by or
on behalf of Midland.
 
     "Midland Exchange" has the meaning specified in the Recitals hereto.
 
     "Midland Exchange Agreement" means an Exchange Agreement in the form and
substance of Exhibit A hereto.
 
     "Midland Exchange Stock Options" has the meaning set forth in Section
2.7(b)(v).
 
     "Midland Exercisable Warrants" means all Midland Common Stock Warrants that
have an exercise price per share of Midland Common Stock that is equal to or
less than the closing price for a share of Midland Common Stock, as reported on
AMEX, on any of the five trading days immediately preceding the second business
day immediately prior to the Closing Date.
 
     "Midland Financial Statements" has the meaning specified in Section 3.1(d).
 
     "Midland Group" has the meaning specified in Section 3.1(l).
 
     "Midland Indemnified Parties" has the meaning specified in Section 4.13(a).
 
     "Midland Intangible Property" has the meaning set forth in Section 3.1(n).
 
     "Midland Litigation" has the meaning set forth in Section 3.1(j).
 
     "Midland Material Agreement" means (a) any written or oral agreement,
contract, commitment, or understanding to which Midland or any of its
Subsidiaries is a party, by which Midland is directly or indirectly bound, or to
which any asset of Midland or any of its Subsidiaries may be subject, the
termination or breach of which, individually or in the aggregate, would have or
could reasonably be expected to have a Material Adverse Effect on Midland or (b)
any instrument defining the rights of security holders, including an indenture,
or material contract that is required by Item 601 of Regulation S-K to be filed
with the SEC as an exhibit to Midland's Annual Report on Form 10-K for the year
ended December 31, 1997.
 
     "Midland Meeting" means the meeting of the shareholders of Midland called
for the purpose of voting on the proposal to approve this Agreement and the
Midland Merger.
 
     "Midland Merger" has the meaning specified in the Recitals hereto.
 
     "Midland Option Exercise Agreement" means an Option Exercise Agreement in
the form and substance of Exhibit D hereto.
 
     "Midland Order" has the meaning specified in Section 3.1(j).
 
     "Midland Permits" has the meaning specified in Section 3.1(i).


                                       A-9
<PAGE>
 
     "Midland Plan" has the meaning specified in Section 3.1(l).
 
     "Midland Preferred Stock" has the meaning set forth in Section 3.1(b).
 
     "Midland Registration Rights Agreement" has the meaning specified in
Section 4.16(b).
 
     "Midland SEC Documents" has the meaning specified in Section 3.1(d).
 
     "Midland Stock Equivalents" means all rights, warrants (including the
Midland Warrants and Midland Common Stock Warrant), options (including the
Midland Stock Options) convertible securities or indebtedness, exchangeable
securities or other instruments, or other rights that (a) are outstanding
immediately after the Effective Time, (b) immediately prior to the Effective
Time, were exercisable for or convertible or exchangeable into, directly or
indirectly, shares of Midland Common Stock at the time of issuance or upon the
passage of time or occurrence of some future event and (c) immediately after the
Effective Time, are exercisable for or convertible or exchangeable into,
directly or indirectly, shares of Newco Common Stock upon the passage of time or
occurrence of some future event.
 
     "Midland Stock Option" means an issued and outstanding option to acquire
shares of Midland Common Stock granted pursuant to any of the Midland Stock
Plans.
 
     "Midland Stock Plans" has the meaning specified in Section 3.1(b).
 
     "Midland Voting Agreement" means a Voting Agreement and Irrevocable Proxy
in the form and substance of Exhibit B hereto.
 
     "Midland Warrant" means the warrants issued and outstanding under that
certain Warrant Agreement dated as of November 1, 1990 by and between Midland
and Stock Transfer Company of America, Inc.
 
     "MM Surviving Corporation" has the meaning specified in Section 2.2.
 
     "Nasdaq" means the Nasdaq National Market.
 
     "Newco" means Vista Energy Resources, Inc., a Delaware corporation.
 
     "Newco Common Stock" has the meaning specified in the Recitals hereto.
 
     "Newco Contribution" has the meaning specified in the Recitals hereto.
 
     "Newco Director Nominee" has the meaning specified in Section 2.5.
 
     "Newco LLC" has the meaning specified in the Recitals hereto.
 
     "Newco Long-Term Incentive Plan" has the meaning specified in Section 4.18.
 
     "Newco Stock Certificate" means a certificate representing shares of Newco
Common Stock.
 
     "Newco Warrant" means a warrant that is exercisable for shares of Newco
Common Stock and which is evidenced by an agreement in the form and substance of
Exhibit C hereto.
 
     "Oil and Gas Interests" means direct and indirect interests in and rights
with respect to oil, gas, mineral, and related properties and assets of any kind
and nature, direct or indirect, including working, royalty, and overriding
royalty interests, production payments, operating rights, net profits interests,
other nonworking interests, and nonoperating interests; all interests in and
rights with respect to Hydrocarbons and other minerals or revenues therefrom and
all contracts in connection therewith and claims and rights thereto (including
all oil and gas leases, operating agreements, unitization and pooling agreements
and orders, division orders, transfer orders, mineral deeds, royalty deeds, oil
and gas sales, exchange, and processing contracts and agreements, and in each
case, interests thereunder), surface interests, fee interests, reversionary
interests, reservations, and concessions; all easements, rights of way,
licenses, permits, leases, and other interests associated with, appurtenant to,
or necessary for the operation of any of the foregoing; and all interests in
equipment and machinery (including well equipment and machinery), oil and gas
production, gathering, transmission, treating, processing, and storage
facilities (including tanks, tank batteries, pipelines, and gathering systems),
pumps, water injection facilities, electric plants, gasoline and gas processing
plants,
                                       A-10

<PAGE>
 
refineries, and other tangible personal property and fixtures associated with,
appurtenant to, or necessary for the operation of any of the foregoing.
References in this Agreement to "Oil and Gas Interests" of a specified Person
means the collective Oil and Gas Interests of such Person and its Subsidiaries.
 
     "Party" has the meaning specified in Section 4.1.
 
     "Partnership Interest" (and correlatives thereof) means, with respect to a
limited partner of Vista, each 1% interest in Vista based on sharing ratios
held, or to be held, of record by a limited partner as of the date of
determination.
 
     "PBGC" means the Pension Benefit Guaranty Corporation.
 
     "Permitted Encumbrances" means (a) Liens for Taxes, assessments, or other
governmental charges or levies if the same shall not at the particular time in
question be due and delinquent or (if foreclosure, distraint, sale, or other
similar proceedings shall not have been commenced or, if commenced, shall have
been stayed) are being contested in good faith by appropriate proceedings and if
a specified Person or any of its Subsidiaries shall have set aside on its books
such reserves segregated to the extent required by sound accounting practices)
as may be required by GAAP or otherwise determined by its board of directors or
general partner to be adequate with respect thereto, (b) Liens of carriers,
warehousemen, mechanics, laborers, materialmen, landlords, vendors, workmen, and
operators arising by operation of law in the ordinary course of business or by a
written agreement existing as of the date hereof and necessary or incident to
the exploration, development, operation, and maintenance of Hydrocarbon
properties and related facilities and assets for sums not yet due or being
contested in good faith by appropriate proceedings, if such Person or any of its
Subsidiaries shall have set aside on its books such reserves (segregated to the
extent required by sound accounting practices) as may be required by GAAP or
otherwise determined by its board of directors or general partner to be adequate
with respect thereto, (c) Liens incurred in the ordinary course of business in
connection with worker's compensation, unemployment insurance, and other social
security legislation (other than ERISA), (d) Liens incurred in the ordinary
course of business to secure the performance of bids, tenders, trade contracts,
leases (statutory only), statutory obligations, surety and appeal bonds,
performance and return-of-money bonds, and other obligations of a like nature,
(e) Liens, easements, rights-of-way, restrictions, servitudes, permits,
conditions, covenants, exceptions, reservations, and other similar encumbrances
incurred in the ordinary course of business or existing on property and not in
the aggregate materially impairing the value of the assets of such Person or any
of its Subsidiaries or interfering with the ordinary conduct of such Person or
any of its Subsidiaries' business or rights to its assets, (f) Liens arising
pursuant to Section 9.319 of the Texas Business and Commerce Code and all other
similar Liens created or arising by operation of law to secure a party's
obligations as a purchaser of oil and gas, (g) all rights to consent by,
required notices to, filings with, or other actions by Governmental Entities to
the extent customarily obtained subsequent to the Closing for transactions
similar to the Midland Merger and the Vista Exchange, (h) farmout, carried
working interest, joint operating, unitization, hedging agreements, royalty,
overriding royalty, sales, and similar agreements relating to the exploration or
development of, or production from, Hydrocarbon properties entered into in the
ordinary course of business and not in violation of Section 4.1, (i) any
defects, irregularities, or deficiencies in title to easements, rights-of-way,
or other surface use agreements that do not have a Material Adverse Effect on
the value of any asset of such Person or any of its Subsidiaries, (j)
preferential rights to purchase and Third-Party Consents that would not be
activated or triggered by either the Midland Merger or the Vista Exchange and
the other transactions contemplated by this Agreement, (k) Liens approved in
writing by or on behalf of Vista, (l) in the case of Vista, Liens and security
interests securing Vista's senior credit facility and (m) in the case of
Midland, Liens and security interests securing Midland's senior credit facility.

     "Person" means any natural person, corporation, limited or general
partnership, limited liability company, joint stock company, joint venture,
association, company, trust, bank, trust company, land trust, business trust, or
other entity or organization, whether or not a Governmental Entity.
 
     "Providing Party" has the meaning specified in Section 4.2.
 
     "Proxy Statement" has the meaning specified in Section 3.1(c)(iii).
 
     "Release" has the meaning specified in Section 3.1(o)(iii).


                                      A-11
<PAGE>

     "Remedial Action" has the meaning set forth in Section 3.1(o)(iv).
 
     "Representative" means, with respect to any Person, any director, officer,
general partner, employee, agent, advisor (including legal, accounting, and
financial advisors), Affiliate, or other representative of such Person or any of
its Subsidiaries.
 
     "Requesting Party" has the meaning specified in Section 4.2.
 
     "Responsible Officer" means, with respect to any corporation, the
President, the Chief Executive Officer, the Chief Operating Officer, the Chief
Financial Officer, or any Vice President or other member of executive management
of such corporation.
 
     "Rule 145 Affiliates" has the meaning specified in Section 4.9.
 
     "S-4" means the Registration Statement on Form S-4 to be filed by Newco in
connection with the issuance of Newco Common Stock pursuant to the Midland
Merger.
 
     "SEC" means the Securities and Exchange Commission.
 
     "Securities Act" means the Securities Act of 1933.
 
     "Subsidiary" (and correlatives thereof) means, with respect to any Person,
any corporation or other organization, whether incorporated or unincorporated,
of which (a) such Person or any other Subsidiary of such Person is a general
partner or (b) at least a majority of the securities or other interests having
by their terms ordinary voting power to elect a majority of the board of
directors or others performing similar functions with respect to such
corporation or other organization is, directly or indirectly, owned or
controlled by such Person or by any one or more of its Subsidiaries, or by such
Person and any one or more of its Subsidiaries.
 
     "Tax" (and, with correlative meaning, "Taxes") has the meaning specified in
Section 3.1(k).
 
     "Tax Returns" has the meaning specified in Section 3.1(k).
 
     "TBCA" means the Texas Business Corporation Act, as amended.
 
     "Termination Agreement" has the meaning specified in Section 4.17.
 
     "Texas Secretary of State" means the Secretary of State of the State of
Texas.
 
     "Third-Party Consent" means the consent or approval of any Person other
than Vista, Midland, Newco, Merger Sub, or any of their respective Subsidiaries,
or any Governmental Entity.
 
     "Vista" means Vista Resources Partners, L.P., a Texas limited partnership.
 
     "Vista Acquisition Proposal" has the meaning specified in Section 4.4(b).
 
     "Vista Benefit Program or Agreement" has the meaning specified in Section
3.2(l).
 
     "Vista Disclosure Schedule" means the Vista Disclosure Schedule attached
hereto and any documents listed on such Vista Disclosure Schedule and expressly
incorporated therein by reference, true and correct copies of which have been
delivered to Midland.
 
     "Vista Engineering Report" means the oil and gas reserve engineering report
concerning the Oil and Gas Interests of Vista as of January 1, 1998 prepared by
Williamson Petroleum Consultants, Inc., and provided to Midland by or on behalf
of Vista.
 
     "Vista Exchange" has the meaning specified in the Recitals hereto.
 
     "Vista Exchange Agreement" means an Exchange Agreement in the form and
substance of Exhibit E hereto.
 
     "Vista GP Conversion Stock Number" means 1.60089817, as such number may be
changed pursuant to Section 2.8.
 

                                      A-12
<PAGE>
 
     "Vista GP Conversion Warrant Number" means 1.16511028, as such number may
be changed pursuant to Section 2.8.
 
     "Vista GP Exchange" has the meaning specified in the Recitals hereto.
 
     "Vista Group" has the meaning specified in Section 3.2(l).
 
     "Vista Indemnified Parties" has the meaning specified in Section 4.13(b).
 
     "Vista Intangible Property" has the meaning specified in Section 3.2(n).
 
     "Vista Litigation" has the meaning specified in Section 3.2(j).
 
     "Vista LP Conversion Stock Number" means 117,674.06, as such number may be
changed pursuant to Section 2.8.
 
     "Vista LP Conversion Warrant Number" means 85,641.46, as such number may be
changed pursuant to Section 2.8.
 
     "Vista LP Exchange" has the meaning set forth in the Recitals hereto.
 
     "Vista Material Agreement" means any instrument defining the rights of
security holders, including an indenture, or material contract that would be
required by Item 601 of Regulation S-K to be filed by Vista with the SEC if
Vista were subject to the periodic reporting requirements of Section 12(b),
12(g), or 15(d) of the Exchange Act.
 
     "Vista Order" has the meaning specified in Section 3.2(j).
 
     "Vista Permits" has the meaning specified in Section 3.2(i).
 
     "Vista Plan" has the meaning specified in Section 3.2(l).
 
     "Vista Registration Rights Agreement" has the meaning specified in Section
4.16(a).
 
     "Vista Sub" means Vista Resources, Inc., a Texas corporation and a direct
wholly-owned subsidiary of Vista.
 
     "Voting Debt" has the meaning specified in Section 3.1(b).
 
     1.2 REFERENCES AND TITLES. All references in this Agreement to Exhibits,
Schedules, Articles, Sections, subsections, and other subdivisions refer to the
corresponding Exhibits, Schedules, Articles, Sections, subsections, and other
subdivisions of this Agreement unless expressly provided otherwise. Titles
appearing at the beginning of any Articles, Sections, subsections, or other
subdivisions of this Agreement are for convenience only, do not constitute any
part of such Articles, Sections, subsections, or other subdivisions, and shall
be disregarded in construing the language contained in such subdivisions. The
words "this Agreement," "herein," "hereby," "hereunder," and "hereof," and words
of similar import, refer to this Agreement as a whole and not to any particular
subdivision unless expressly so limited. The words "this Section" and "this
subsection," and words of similar import, refer only to the Sections or
subsections hereof in which such words occur. The word "or" is not exclusive,
and the word "including" (in its various forms) means "including without
limitation." Pronouns in masculine, feminine, or neuter genders shall be
construed to state and include any other gender, and words, terms, and titles
(including terms defined herein) in the singular form shall be construed to
include the plural and vice versa, unless the context otherwise expressly
requires.
 
     As used in the representations and warranties contained in this Agreement,
the phrase "to the knowledge of" shall mean, with respect to a specified
representing party, that the Responsible Officers of such representing party,
individually or collectively, have conducted such investigations and inquiries
that they reasonably believe to be most likely to confirm the truth and accuracy
of the matter being represented and warranted (or have caused such
investigations and inquiries to be made under their supervision) and, after
evaluating the findings of such investigations and inquiries, either (a) know
that the matter being represented and warranted is true and accurate or (b) have
no reason to believe that the matter being represented and warranted is not true
and accurate.
 

                                      A-13
<PAGE>
 
                                   ARTICLE 2
 
                            THE MERGER AND EXCHANGES
 
     2.1 THE MIDLAND MERGER. Subject to the terms and conditions set forth in
this Agreement, at the Effective Time (as hereinafter defined) Merger Sub shall
be merged with and into Midland in accordance with the provisions of this
Agreement and in accordance with the TBCA.
 
     2.2 EFFECT OF THE MIDLAND MERGER. Upon the effectiveness of the Midland
Merger, the separate existence of Merger Sub shall cease and Midland, as the
surviving corporation in the Midland Merger (the "MM Surviving Corporation"),
shall continue its corporate existence under the laws of the State of Texas. The
Midland Merger shall have the effects specified in the TBCA.
 
     2.3 CERTIFICATES OF INCORPORATION OF NEWCO, MIDLAND AND NEWCO SUB. The
Articles of Incorporation of Midland, as in effect immediately prior to the
Effective Time (as hereinafter defined) shall be the Articles of Incorporation
of the MM Surviving Corporation until thereafter amended in accordance with its
terms and as provided by applicable law.
 
     2.4 BYLAWS. The Bylaws of Merger Sub in effect immediately prior to the
Midland Merger shall be the bylaws of the MM Surviving Corporation, until
thereafter amended in accordance with its terms and as provided by applicable
law. Newco and Merger Sub have delivered true and correct copies of their Bylaws
to each of Vista and Midland.
 
     2.5 DIRECTORS. Immediately prior to the Closing, Vista shall take such
action as may be necessary as the then sole shareholder of Newco so as to cause
the directors of Newco at the Effective Time to be as set forth below:
 
         C. Randall Hill
         Steven D. Gray
         Kenneth A. Hersh
         David R. Albin
         John S. Foster
         Midland representative to be named by Midland's Board of Directors
         prior to Closing Date
 
     Vista as set forth in this Section 2.5 shall have the right to initially
nominate eight of the nine directors and Midland shall have the right to
initially nominate one of the nine directors who shall serve as directors of
Newco commencing as of the Effective Time. Each nominee for director of Newco
identified as such above (a "Newco Director Nominee") will hold office until the
1999 annual meeting of Newco, and in all cases, until his or her respective
successor is duly elected or appointed and qualified in the manner provided in
the Certificate of Incorporation or Bylaws of Newco, or as otherwise provided by
applicable law. If prior to the Effective Time a Newco Director Nominee selected
by Vista or Midland shall decline or be unable to serve as a director of Newco
or whose nomination shall be withdrawn by Vista or Midland, as applicable, then
Vista or Midland, as appropriate, shall be entitled to nominate a replacement
for such Newco Director Nominee, who shall thereafter become a Newco Director
Nominee, provided that such person shall be reasonably acceptable to each of the
other parties to this Agreement and this Agreement shall be amended by the
parties to the extent necessary to reflect such action.
 
     The directors of the MM Surviving Corporation shall be the same as the
directors of Newco set forth in this Section 2.5.
 

                                      A-14
<PAGE>
 
     2.6 OFFICERS. The initial senior executive officers of Newco immediately
following the Effective Time shall be as set forth below:
 
<TABLE>
<S>                                           <C>
C. Randall Hill.............................  Chairman, Chief Executive Officer,
                                              Chief Financial Officer, Treasurer
                                              and Assistant Secretary
Steven D. Gray..............................  President, Assistant Treasurer and
                                              Assistant Secretary
R. Cory Richards............................  Executive Vice President --
                                              Exploration and Secretary
</TABLE>

     Each such officer of Newco will hold office from the Effective Time until
his respective successor is duly elected or appointed and qualified in the
manner provided in the Certificate of Incorporation or Bylaws of Newco, or as
otherwise provided by applicable law. The names, titles, and responsibilities of
the other individuals who initially will hold officerships with Newco shall be
determined by Vista prior to the Effective Time, and the election of those
persons shall be considered by the Board of Directors of Newco immediately
following the Effective Time.
 
     The officers of Merger Sub immediately prior to the Effective Time shall be
the initial officers of the MM Surviving Corporation until their respective
successors are duly elected or appointed and qualified in the manner provided in
the Certificate of Incorporation or Bylaws of the MM Surviving Corporation, or
as otherwise provided by applicable law.
 
     2.7 EFFECT ON SECURITIES.
 
          (a) MERGER SUB STOCK. At the Effective Time, by virtue of the Midland
     Merger and without any action on the part of any holder thereof, each share
     of Merger Sub Common Stock outstanding immediately prior to the Effective
     Time shall be converted into and shall become one validly issued, fully
     paid, and nonassessable share of common stock, par value $.01 per share, of
     the MM Surviving Corporation.
 
          (b) MIDLAND SECURITIES.
 
             (i) CONVERSION. At the Effective Time, by virtue of the Midland
        Merger and without any action on the part of any holder thereof (but
        subject to the provisions of Section 2.10(e)), all shares of Midland
        Common Stock that are issued and outstanding immediately prior to the
        Effective Time shall be converted into the right to receive shares of
        Newco Common Stock, with each such share of Midland Common Stock being
        converted into a number of shares of Newco Common Stock equal to the
        Midland Conversion Number. Each such share of Midland Common Stock, when
        so converted, shall automatically be cancelled and retired, shall cease
        to exist, and shall no longer be outstanding; and the holder of any
        certificate representing any such shares shall cease to have any rights
        with respect thereto, except the right to receive the shares of Newco
        Common Stock to be issued in exchange therefor (along with any cash in
        lieu of fractional shares of Newco Common Stock as provided in Section
        2.10(e) and any unpaid dividends and distributions with respect to such
        shares of Newco Common Stock as provided in Section 2.10(c)), without
        interest, upon the surrender of such certificate in accordance with
        Section 2.10.
 
             (ii) MIDLAND TREASURY STOCK. At the Effective Time, by virtue of
        the Midland Merger and without any action on the part of any holder
        thereof, all shares of Midland Common Stock that are issued and held as
        treasury stock shall be cancelled and retired and shall cease to exist
        and no shares of Newco Common Stock, cash, or other consideration shall
        be paid or payable in exchange therefor.
 
             (iii) MIDLAND STOCK OPTIONS. All Midland Stock Options (other than
        the Midland Exchange Stock Options) shall remain outstanding following
        the Effective Time. At the Effective Time, by virtue of the Midland
        Merger and without any action on the part of Midland or any holder
        thereof, each such Midland Stock Option (other than the Midland Exchange
        Stock Options) shall be


                                      A-15
<PAGE>
 
        assumed by Newco in such manner that Newco is a corporation assuming a
        stock option in a transaction to which Section 424(a) applied within the
        meaning of Section 424 of the Code or, to the extent that Section 424 of
        the Code does not apply to any such Midland Stock Option (other than the
        Midland Exchange Stock Options), would be such a corporation were
        Section 424 applicable to such option. Subject to the terms of the
        Midland Option Exercise Agreement, each Midland Stock Option (other than
        the Midland Exchange Stock Options) assumed by Newco shall be
        exercisable on the same terms and conditions as apply immediately prior
        to the Effective Time, except that each such Midland Stock Option (other
        than the Midland Exchange Stock Options) shall be exercisable for that
        whole number of shares of Newco Common Stock (to the nearest whole
        share) into which the number of shares of Midland Common Stock subject
        to such Midland Stock Option (other than the Midland Exchange Stock
        Options) immediately prior to the Effective Time would be converted
        under paragraph (i) of this subsection and the option price per share of
        Newco Common Stock shall be an amount equal to the option price per
        share of Midland Common Stock subject to such Midland Stock Option
        (other than the Midland Exchange Stock Options) in effect immediately
        prior to the Effective Time divided by the Midland Conversion Number
        (the option price per share, as so determined, being rounded upward to
        the nearest full cent). No payment shall be made for fractional
        interests.
 
             (iv) MIDLAND WARRANTS AND MIDLAND COMMON STOCK WARRANTS. All
        Midland Warrants and Midland Common Stock Warrants shall remain
        outstanding following the Effective Time. At the Effective Time, by
        virtue of the Midland Merger and without any action on the part of
        Midland or any holder thereof, each such Midland Warrant and Midland
        Common Stock Warrant shall be assumed by Newco and shall be exercisable
        on the same terms and conditions as apply immediately prior to the
        Effective Time, except that each Midland Warrant and Midland Common
        Stock Warrant shall be exercisable for that number of shares of Newco
        Common Stock into which the number of shares of Midland Common Stock
        subject to such Midland Warrant or Midland Common Stock Warrant, as
        applicable, immediately prior to the Effective Time would be converted
        under paragraph (i) of this subsection. No payment shall be made for
        fractional interests.
 
             (v) MIDLAND EXCHANGE STOCK OPTIONS. Pursuant to the terms of the
        Midland Exchange Agreement contemporaneously entered into between Newco
        and each holder of the Midland Stock Options described on Schedule 2.7
        of the Midland Disclosure Schedule (the "Midland Exchange Stock
        Options"), at the Effective Time, without any action on the part of any
        holder thereof, each Midland Exchange Stock Option will be exchanged for
        a Newco Warrant that is exercisable for that whole number of shares of
        Newco Common Stock (to the nearest whole share) equal to the product of
        (x) .725 times (y) the number of shares of Newco Common Stock into which
        the shares of Midland Common Stock subject to such Midland Exchange
        Stock Option would be converted under paragraph (i) of this subsection.
        Pursuant to the Midland Exchange Agreement, no payment shall be made for
        fractional interests. Pursuant to the terms of the Midland Exchange
        Agreement, each Midland Exchange Stock Option subject thereto shall be
        terminated immediately following their exchange for a Newco Warrant.
 
     2.8 VISTA EXCHANGE AGREEMENTS. Within 30 days from the date hereof, Newco
and Vista agree to cause Newco to enter into Vista Exchange Agreements in
connection with the Vista GP Exchange and the Vista LP Exchange, respectively,
with all of the holders of the GP Common Stock and all of the Partnership
Interests. Pursuant to such Vista Exchange Agreements at the Effective Time,
without any action on the part of any holder thereof, (a) each share of GP
Common Stock that is issued and outstanding prior to the Effective Time shall be
exchanged for (i) a number of shares of Newco Common Stock equal to the Vista GP
Conversion Stock Number and (ii) a Newco Warrant that is exercisable for a
number of shares of Newco Common Stock equal to the Vista GP Conversion Warrant
Number and (b) each Partnership Interest that is issued and outstanding prior to
the Effective Time shall be exchanged for (i) a number of shares of Newco Common
Stock equal to the Vista LP Conversion Stock Number and (ii) a Newco Warrant
that is exercisable for a number of shares of Newco Common Stock equal to the
Vista LP Conversion Warrant


                                      A-16
<PAGE>
 
Number. As provided in the Exchange Agreement, any fractional Partnership
Interest shall be likewise exchanged on a pro rata basis.
 
     2.9 ADJUSTMENTS. (a) The parties hereto mutually agree that,
notwithstanding anything in this Agreement to the contrary, each of the Vista GP
Conversion Stock Number, the Vista LP Conversion Stock Number, the Vista GP
Conversion Warrant Number and the Vista LP Conversion Warrant Number shall be
increased or decreased, as necessary, immediately prior to the Effective Time
such that (i) the aggregate percentage of shares of Newco Common Stock that the
holders of GP Common Stock and the holders of Partnership Interests shall be
entitled to receive at the Effective Time shall equal 72.5% of the shares of
Newco Common Stock that will be outstanding calculated on a Fully Diluted Basis
immediately after the Effective Time and (ii) the aggregate percentage of shares
of Newco Common Stock issuable upon exercise of the Newco Warrants that the
holders of GP Common Stock and the holders of Partnership Interests shall be
entitled to receive shall equal 72.5% of the shares of Newco Common Stock that
is issuable upon the exercise of (x) all Midland Warrants outstanding
immediately after the Effective Time, (y) all Newco Warrants issued pursuant to
the Midland Exchange and (z) all Newco Warrants issuable pursuant to the Vista
Exchange. Subject to Section 2.9(b), 2.9(c), any such adjustments to the Vista
GP Conversion Stock Number, the Vista LP Conversion Stock Number, the Vista GP
Conversion Warrant Number or the Vista LP Conversion Warrant Number shall be
made not later than two business days prior to the Closing and shall be
determined by Newco's independent auditors Arthur Andersen LLP.
 
     (b) Pursuant to the Vista Exchange Agreements, effective as of the last day
of the fourth calendar month immediately following the calendar month in which
the Closing Date occurred, Newco shall cause its independent auditors Arthur
Anderson LLP to redetermine the Vista GP Conversion Stock Number and the Vista
LP Conversion Stock Number by redetermining, as of such date, Fully Diluted
Basis only to the extent necessary so as to reflect the number of shares of
Newco Common Stock, if any, issued after the Effective Time as a result of the
exercise of any Midland Stock Options. In the event any such adjustment to the
Vista GP Conversion Stock Number and the Vista LP Conversion Stock Number is
determined appropriate, then pursuant to the Vista Exchange Agreements, Newco
shall promptly issue to the prior holders of the GP Common Stock and Partnership
Interests their pro rata share of a number of shares of Newco Common Stock equal
to an amount equal to (i) the quotient realized by dividing (x) the number of
shares of Newco Common Stock issued after the Effective Time as a result of the
exercise of any Midland Stock Options by (y) .275 minus (ii) the number of
shares of Newco Common Stock described in clause (x) above.
 
     (c) The parties hereto mutually agree that, notwithstanding anything in
this Agreement to the contrary, (i) at the Effective Time, by virtue of the
Midland Merger, the holders of shares of Midland Common Stock shall receive
shares of Newco Common Stock issued in exchange therefor equal to 27.5% of the
shares of Newco Common Stock that will be outstanding immediately after the
Effective Time (calculated giving effect to the shares of Newco Common Stock
issued as a result of the Vista Exchange), and (ii) immediately after the
Effective Time, the aggregate percentage of shares of Newco Common Stock
issuable upon exercise of (a) all Midland Warrants outstanding immediately after
the Effective Time, and (b) all Newco Warrants issued pursuant to the Midland
Exchange, shall equal 27.5% of the shares of Newco Common Stock that is issuable
upon exercise of (x) all Midland Warrants outstanding immediately after the
Effective Time, (y) all Newco Warrants issued pursuant to the Midland Exchange,
and (z) all Newco Warrants issuable pursuant to the Vista Exchange.
 
     2.10 EXCHANGE OF CERTIFICATES.
 
          (a) EXCHANGE FUND. Immediately after the Effective Time, Newco shall
     deposit with the Exchange Agent, for the benefit of the holders of shares
     of Midland Common Stock and for exchange in accordance with this Agreement,
     certificates representing the shares of Newco Common Stock to be issued in
     exchange for shares of Midland Common Stock pursuant to Section 2.7. Such
     shares of Newco Common Stock, together with any dividends or distributions
     with respect thereto (as provided in subSection (c) of this Section 2.10),
     are referred to herein as the "Exchange Fund." The Exchange Agent, pursuant
     to irrevocable instructions consistent with the terms of this Agreement,
     shall deliver the Newco Common Stock to be issued pursuant to Section 2.7
     out of the Exchange Fund, and the Exchange
 

                                      A-17
<PAGE>

     Fund shall not be used for any other purpose. The Exchange Agent shall not
     be entitled to vote or exercise any rights of ownership with respect to the
     Newco Common Stock held by it from time to time hereunder, except that it
     shall receive and hold all dividends or other distributions paid or
     distributed with respect thereto for the account of Persons entitled
     thereto.
 
          (b) EXCHANGE PROCEDURES.
 
             (i) As soon as reasonably practicable after the Effective Time,
        Newco shall cause the Exchange Agent to mail to each holder of record of
        a Midland Certificate that, immediately prior to the Effective Time,
        represented shares of Midland Common Stock converted into Newco Common
        Stock pursuant to Section 2.7 a letter of transmittal to be used to
        effect the exchange of such Midland Certificate for a Newco Stock
        Certificate and cash in lieu of fractional shares, along with
        instructions for using such letter of transmittal to effect such
        exchange. The letter of transmittal (or the instructions thereto) shall
        specify that delivery of any Midland Certificate shall be effected, and
        risk of loss and title thereto shall pass, only upon delivery of such
        Midland Certificate to the Exchange Agent and shall be in such form and
        have such other provisions as Newco may reasonably specify.
 
             (ii) Upon delivery to the Exchange Agent of, together with the
        surrender of a Midland Certificate, if applicable, a duly completed and
        executed letter of transmittal and any other required documents
        (including, in the case of any Rule 145 Affiliate, an Affiliate
        Agreement from such Person as described in Section 4.9, if not
        theretofore delivered to Newco), (A) the holder of such Midland
        Certificate shall be entitled to receive in exchange therefor a Newco
        Stock Certificate representing the number of whole shares of Newco
        Common Stock that such holder has the right to receive pursuant to
        Section 2.7, any cash in lieu of fractional shares of Newco Common Stock
        as provided in subSection (e) of this Section, and any unpaid dividends
        and distributions that such holder has the right to receive pursuant to
        subSection (c) of this Section (after giving effect to any required
        withholding of taxes) and (B) the Midland Certificate, if any, so
        surrendered shall forthwith be cancelled. No interest shall be paid or
        accrued on the cash in lieu of fractional shares and unpaid dividends
        and distributions, if any, payable to holders of Midland Certificates.
 
             (iii) In the event of a transfer of ownership of Midland Common
        Stock that is not registered in the transfer records of Midland, a Newco
        Stock Certificate representing the appropriate number of shares of Newco
        Common Stock (along with any cash in lieu of fractional shares and any
        unpaid dividends and distributions that such holder has the right to
        receive) may be issued to a transferee if the Midland Certificate
        representing such shares of Midland Common Stock is presented to the
        Exchange Agent accompanied by all documents required to evidence and
        effect such transfer and to evidence that any applicable stock transfer
        taxes have been paid.
 
             (iv) Until surrendered as contemplated by this subsection, each
        Midland Certificate shall be deemed at any time after the Effective Time
        to represent only the right to receive upon such surrender a Newco Stock
        Certificate representing shares of Newco Common Stock (along with any
        cash in lieu of fractional shares and any unpaid dividends and
        distributions).
 
          (c) DISTRIBUTIONS WITH RESPECT TO UNEXCHANGED SHARES. No dividends or
     other distributions with respect to Newco Common Stock declared or made
     after the Effective Time with a record date after the Effective Time shall
     be paid to the holder of any unsurrendered Midland Certificate. Subject to
     the effect of applicable laws, (i) at the time of the surrender of a
     Midland Certificate for exchange in accordance with the provisions of this
     Section, there shall be paid to the surrendering holder, without interest,
     the amount of dividends or other distributions (having a record date after
     the Effective Time but on or prior to surrender and a payment date on or
     prior to surrender) theretofore paid with respect to the number of whole
     shares of Newco Common Stock that such holder is entitled to receive (less
     the amount of any withholding taxes that may be required with respect
     thereto) and (ii) at the appropriate payment date, there shall be paid to
     the surrendering holder, without interest, the amount of dividends or other
     distributions (having a record date after the Effective Time but on or
     prior to surrender and a payment


                                      A-18
<PAGE>
 
     date subsequent to surrender) payable with respect to the number of whole
     shares of Newco Common Stock that such holder receives (less the amount of
     any withholding taxes that may be required with respect thereto).
 
          (d) NO FURTHER OWNERSHIP RIGHTS IN MIDLAND COMMON STOCK. All shares of
     Newco Common Stock issued upon the surrender for exchange of shares of
     Midland Common Stock in accordance with the terms hereof (including any
     cash paid pursuant to subSection (c) or (e) of this Section) shall be
     deemed to have been issued in full satisfaction of all rights pertaining to
     such shares of Midland Common Stock. After the Effective Time, there shall
     be no further registration of transfers on the MM Surviving Corporation's
     stock transfer books of the shares of Midland Common Stock that were
     outstanding immediately prior to the Effective Time. If, after the
     Effective Time, a Midland Certificate is presented to the MM Surviving
     Corporation for any reason, it shall be cancelled and exchanged as provided
     in this Section.
 
          (e) TREATMENT OF FRACTIONAL SHARES.
 
             (i) No Newco Stock Certificates or scrip representing fractional
        shares of Newco Common Stock shall be issued in the Midland Merger, and
        except as provided in this subsection, no dividend or other
        distribution, stock split, or interest shall relate to any such
        fractional share and such fractional share shall not entitle the owner
        thereof to vote or to any other rights of a shareholder of Newco.
 
             (ii) As soon as practicable following the Effective Time, the
        Exchange Agent shall determine the excess of (A) the number of whole
        shares of Newco Common Stock delivered to the Exchange Agent by Newco
        pursuant to subSection (a) of this Section over (B) the aggregate number
        of whole shares of Newco Common Stock issuable to holders of Midland
        Common Stock pursuant to Section 2.7 (such excess being referred to
        herein as the "Excess Shares") and the Exchange Agent, as the agent for
        the former holders of Midland Common Stock, shall sell the Excess Shares
        at the prevailing prices on the securities exchange on which the shares
        of Newco Common Stock are traded. The sale of the Excess Shares by the
        Exchange Agent shall be executed on such securities exchange through one
        or more member firms of such securities exchange and shall be executed
        in round lots to the extent practicable. Newco shall pay all
        commissions, transfer taxes, and other out-of-pocket transaction costs
        incurred in connection with such sale of the Excess Shares.
 
             (iii) In lieu of any fractional share of Newco Common Stock to
        which a holder of Midland Common Stock would otherwise be entitled, such
        holder, upon surrender of a Midland Certificate as described in this
        Section, shall be paid an amount in cash (without interest) equal to
        such holder's proportionate interest in the sum of (A) the net proceeds
        from the sale of the Excess Shares in accordance with the provisions of
        paragraph (2) of this subsection and (B) the aggregate dividends or
        other distributions that are payable with respect to the Excess Shares
        pursuant to subsection (c) of this Section, such proportionate interest
        to be determined by dividing the amount of the fractional share
        interests to which such holder would otherwise be entitled by the
        aggregate amount of fractional share interests to which all holders of
        Midland Common Stock would otherwise be entitled. Until the net proceeds
        of the sale of Excess Shares (along with any dividends or distributions
        with respect thereto have been distributed to the former shareholders of
        Midland), the Exchange Agent will hold such amounts in trust for the
        former holders of Midland Common Stock.
 
          (f) TERMINATION OF EXCHANGE FUND. Any portion of the Exchange Fund and
     cash held by the Exchange Agent in accordance with the terms of this
     Section that remains unclaimed by the former shareholders of Midland for a
     period of one year following the Effective Time shall be delivered to
     Newco, upon demand. Thereafter, any former shareholders of Midland who have
     not theretofore complied with the provisions of this Section shall look
     only to Newco for payment of their claim for Newco Common Stock, any cash
     in lieu of fractional shares of Newco Common Stock, and any dividends or
     distributions with respect to Newco Common Stock (all without interest).


                                      A-19
<PAGE>
 
          (g) NO LIABILITY. None of Newco, the MM Surviving Corporation, the
     Exchange Agent, or any other Person shall be liable to any former holder of
     shares of Midland Common Stock for any amount properly delivered to any
     public official pursuant to any applicable abandoned property, escheat, or
     similar law. Any amounts remaining unclaimed by former holders of shares of
     Midland Common Stock for a period of two years following the Effective Time
     (or such earlier date immediately prior to the time at which such amounts
     would otherwise escheat to or become property of any governmental entity)
     shall, to the extent permitted by applicable law, become the property of
     Newco free and clear of any claims or interest of any such holders or their
     successors, assigns, or personal representative previously entitled
     thereto.
 
          (h) LOST, STOLEN, OR DESTROYED MIDLAND CERTIFICATES. If any Midland
     Certificate shall have been lost, stolen, or destroyed, upon the making of
     an affidavit of that fact by the Person claiming such Midland Certificate
     to be lost, stolen, or destroyed and, if required by Newco, the posting by
     such Person of a bond in such reasonable amount as Newco may direct as an
     indemnity against any claim that may be made against it with respect to
     such Midland Certificate, the Exchange Agent shall issue in exchange for
     such lost, stolen, or destroyed Midland Certificate the shares of Newco
     Common Stock (along with any cash in lieu of fractional shares pursuant to
     subsection (e) of this Section and any unpaid dividends and distributions
     pursuant to subsection (c) of this Section) deliverable with respect
     thereto pursuant to this Agreement.
 
     2.11 CLOSING. The Closing shall take place on the Closing Date. The Closing
shall take place at such time as is agreed upon by Vista and Midland and shall
take place at the offices of Vinson & Elkins, L.L.P., 2001 Ross Avenue, Suite
3700, Dallas, Texas 75201, unless another place is agreed to by Vista and
Midland.
 
     2.12 EFFECTIVE TIME OF THE MERGER. In connection with the Midland Merger,
the parties hereto will file with the Texas Secretary of State on the Closing
Date articles of merger (the "Midland Articles of Merger"). Notwithstanding
anything in this Section to the contrary, the articles of merger referred to in
this Section may be filed prior to the Closing Date or prior to the Closing so
long as it provides for an effective time that occurs on or after the Closing.
The Midland Merger shall become effective immediately upon the filing of the
Midland Articles of Merger with the Texas Secretary of State, or at such later
time specified in the Midland Articles of Merger (the "Effective Time").
 
     2.13 SHAREHOLDER APPROVALS OBTAINED.
 
          (a) Vista, in its capacity as the sole shareholder of Newco, by its
     execution hereof, approves and adopts this Agreement and the transactions
     contemplated hereby.
 
          (b) Newco, in its capacity as the sole shareholder of Merger Sub, by
     its execution hereof, approves and adopts this Agreement and the
     transactions contemplated hereby.
 
                                   ARTICLE 3
 
                         REPRESENTATIONS AND WARRANTIES
 
     3.1 REPRESENTATIONS AND WARRANTIES OF MIDLAND. Midland hereby represents
and warrants to Vista, Newco and Merger Sub as follows:
 
          (a) ORGANIZATION, STANDING AND POWER. Each of Midland and its
     Subsidiaries is a corporation or partnership duly organized, validly
     existing and in good standing under the laws of its state of incorporation
     or organization, has all requisite power and authority to own, lease, and
     operate its properties and to carry on its business as now being conducted,
     and is duly qualified and in good standing to do business in each
     jurisdiction in which the business it is conducting, or the operation,
     ownership, or leasing of its properties, makes such qualification
     necessary, other than in such jurisdictions where the failure so to qualify
     would not have a Material Adverse Effect (as defined below) on Midland.
     Midland has heretofore delivered to Vista and Newco complete and correct
     copies of its and each of its Subsidiaries' Articles of Incorporation and
     Bylaws, each as amended to date. The respective jurisdictions of
     incorporation or organization of Midland's Subsidiaries are identified on
     Schedule 3.1(a) of the


                                      A-20
<PAGE>

     Midland Disclosure Schedule. Other than Midland's Subsidiaries disclosed on
     Schedule 3.1(a) of the Midland Disclosure Schedule, Midland has no other
     Subsidiary. As used in this Agreement, a "Material Adverse Effect" or
     "Material Adverse Change" shall mean, in respect of Midland or Vista, as
     the case may be, any effect or change that is or, as far as can be
     reasonably determined, may be materially adverse to the business,
     operations, assets, condition (financial or otherwise) or results of
     operations of such party and its Subsidiaries taken as a whole.
 
          (b) CAPITAL STRUCTURE. As of the date hereof, the authorized capital
     stock of Midland consists of 80,000,000 shares of Midland Common Stock and
     20,000,000 shares of preferred stock, par value $.01 per share ("Midland
     Preferred Stock"). At the close of business on April 30, 1998: (i)
     4,463,499 shares of Midland Common Stock were issued and outstanding; (ii)
     no shares of Midland Preferred Stock were issued and outstanding; (iii)
     1,235,000, 236,500, and 398,000 Midland Common Stock were authorized and
     available for grant pursuant to the Midland Resources, Inc. 1997 Board of
     Directors' Stock Incentive Plan, the 1994 Midland Resources, Inc. Long-Term
     Incentive Plan, and the 1996 Midland Resources, Inc. Long-Term Incentive
     Plan (collectively, the "Midland Stock Plans"), respectively; (iv) 123,500,
     236,500, and 398,000 shares of Midland Common Stock were reserved for
     issuance pursuant to each of the Midland Stock Plans, respectively; (v)
     1,603,000 shares of Midland Common Stock were subject to issuance under
     Midland Options outstanding as of the date hereof; (vi) 2,253,094 shares of
     Midland Common Stock were subject to issuance upon exercise of the Midland
     Warrants; (vii) 2,253,094 shares of Midland Common Stock were reserved for
     issuance upon exercise of the Midland Warrants; (viii) no shares of Midland
     Common Stock were held by Midland in its treasury; (ix) 270,000 shares of
     Midland Common Stock were subject to issuance upon exercise of the Midland
     Common Stock Warrants, (x) 270,000 shares of Midland Common Stock were
     reserved for issuance upon exercise of the Midland Common Stock Warrants
     and (xi) no bonds, debentures, notes or other indebtedness having the right
     to vote (or convertible into securities having the right to vote) ("Voting
     Debt") on any matters on which shareholders of Midland may vote were issued
     and outstanding. The Midland Resources, Inc. 1995 Board of Directors' Stock
     Incentive Plan has been terminated, however, options for 50,000 shares of
     Midland Common Stock issued thereunder prior to such termination remain
     outstanding. All outstanding shares of Midland Common Stock are validly
     issued, fully paid, and nonassessable and are not subject to preemptive
     rights. Except as set forth on Schedule 3.1(b) of the Midland Disclosure
     Schedule, all outstanding shares of capital stock of the Subsidiaries of
     Midland are owned by Midland, or a direct or indirect wholly-owned
     Subsidiary of Midland, free and clear of all Liens. Except as set forth in
     this Section 3.1(b) or on Schedule 3.1(b) of the Midland Disclosure
     Schedule, and except for changes since April 30, 1998 resulting from the
     subsequent exercise of Midland Options, Midland Warrants, or Midland Common
     Stock Warrants, there are outstanding: (A) no shares of capital stock,
     Voting Debt or other voting securities of Midland; (B) no securities of
     Midland or any Subsidiary of Midland convertible into or exchangeable for
     shares of capital stock, Voting Debt or other voting securities of Midland
     or any Subsidiary of Midland; and (C) no options, warrants, calls, rights
     (including preemptive rights), commitments, or agreements to which Midland
     or any Subsidiary of Midland is a party or by which it is bound in any case
     obligating Midland or any Subsidiary of Midland to issue, deliver, sell,
     purchase, redeem or acquire, or cause to be issued, delivered, sold,
     purchased, redeemed or acquired, additional shares of capital stock or any
     Voting Debt or other voting securities of Midland or of any Subsidiary of
     Midland, or obligating Midland or any Subsidiary of Midland to grant,
     extend, or enter into any such option, warrant, call, right, commitment, or
     agreement. Except for the Midland Voting Agreements, there are not as of
     the date hereof and there will not be at the Effective Time any shareholder
     agreements, voting trusts or other agreements or understandings to which
     Midland is a party or by which it is bound relating to the voting of any
     shares of the capital stock of Midland that will limit in any way the
     solicitation of proxies by or on behalf of Midland from, or the casting of
     votes by, the shareholders of Midland with respect to the Midland Merger.
     There are no restrictions on Midland to vote the stock of any of its
     Subsidiaries. The exercise price or conversion price of each of the
     outstanding Midland Warrants, Midland Common Stock Warrants, Midland
     Options and other Midland Stock Equivalents is set forth on Schedule
     3.1(b).


                                      A-21
<PAGE>
 
          (c) AUTHORITY; NO VIOLATIONS; CONSENTS AND APPROVALS.
 
             (i) The Board of Directors of Midland has approved the Midland
        Merger and this Agreement, and declared the Midland Merger and this
        Agreement to be in the best interests of the shareholders of Midland.
        The directors of Midland have advised Midland and Vista that they intend
        (acting in their capacity as a shareholder of Midland and in accordance
        with the applicable Midland Voting Agreement) to vote or cause to be
        voted all of the shares of Midland Common Stock beneficially owned by
        them and their affiliates in favor of approval of the Midland Merger and
        this Agreement. Midland has all requisite corporate power and authority
        to enter into this Agreement and, subject, with respect to consummation
        of the Midland Merger, to approval of this Agreement and the Midland
        Merger by the shareholders of Midland in accordance with the TBCA and
        the Articles of Incorporation and Bylaws of Midland, to consummate the
        transactions contemplated hereby. The execution and delivery of this
        Agreement and the consummation of the transactions contemplated hereby
        have been duly authorized by all necessary corporate action on the part
        of Midland, subject, with respect to consummation of the Midland Merger,
        to approval of this Agreement and the Midland Merger by the shareholders
        of Midland in accordance with the TBCA and the Articles of Incorporation
        and Bylaws of Midland. This Agreement has been duly executed and
        delivered by Midland and, subject, with respect to consummation of the
        Midland Merger, to approval of this Agreement and the Midland Merger by
        the shareholders of Midland in accordance with the TBCA and the Restated
        Certificate of Incorporation and Restated Bylaws of Midland, and
        assuming this Agreement constitutes the valid and binding obligation of
        Vista, Newco and Merger Sub, constitutes a valid and binding obligation
        of Midland enforceable in accordance with its terms, subject, as to
        enforceability, to bankruptcy, insolvency, reorganization, moratorium
        and other laws of general applicability relating to or affecting
        creditors' rights and to general principles of equity (regardless of
        whether such enforceability is considered in a proceeding in equity or
        at law).
 
             (ii) Except as set forth on Schedule 3.1(c) of the Midland
        Disclosure Schedule, the execution and delivery of this Agreement does
        not, and the consummation of the transactions contemplated hereby and
        compliance with the provisions hereof will not, conflict with, or result
        in any violation of, or default (with or without notice or lapse of
        time, or both) under, or give rise to a right of termination,
        cancellation, or acceleration of any material obligation or to the loss
        of a material benefit under, or give rise to a right of purchase under,
        result in the creation of any Lien upon any of the properties or assets
        of Midland or any of its Subsidiaries under, or otherwise result in a
        material detriment to Midland or any of its Subsidiaries under, any
        provision of (A) the Articles of Incorporation or Bylaws of Midland or
        any provision of the comparable charter or organizational documents of
        any of its Subsidiaries, (B) any loan or credit agreement, note, bond,
        mortgage, indenture, lease, or other agreement, instrument, permit,
        concession, franchise, or license applicable to Midland or any of its
        Subsidiaries, (C) any joint venture or other ownership arrangement, or
        (D) assuming the consents, approvals, authorizations or permits and
        filings or notifications referred to in Section 3.1(c)(iii) are duly and
        timely obtained or made and the approval of the Midland Merger and this
        Agreement by the shareholders of Midland has been obtained, any
        judgment, order, decree, statute, law, ordinance, rule or regulation
        applicable to Midland or any of its Subsidiaries or any of their
        respective properties or assets, other than, in the case of clause (B)
        or (C) in this subsection, any such conflicts, violations, defaults,
        rights, Liens that, individually or in the aggregate, would not have a
        Material Adverse Effect on Midland, materially impair the ability of
        Midland to perform its obligations hereunder, or prevent the
        consummation of any of the transactions contemplated hereby.
 
             (iii) No consent, approval, order or authorization of, or
        registration, declaration or filing with, or permit from any court,
        governmental, regulatory or administrative agency or commission or other
        governmental authority or instrumentality, domestic or foreign (a
        "Governmental Entity"), is required by or with respect to Midland or any
        of its Subsidiaries in connection with the execution and delivery of
        this Agreement by Midland or the consummation by Midland of the
        transactions contemplated hereby, as to which the failure to obtain or
        make would have a Material Adverse


                                      A-22
<PAGE>
 
        Effect on Midland, except for: (A) the filing with the SEC of (1) a
        proxy statement in preliminary and definitive form relating to the
        meeting of the shareholders of Midland to be held in connection with the
        Midland Merger (the "Proxy Statement") and (2) such reports under
        Section 13(a) of the Exchange Act and such other compliance with the
        Exchange Act and the rules and regulations thereunder, as may be
        required in connection with this Agreement and the transactions
        contemplated hereby; (B) the filing of the Midland Articles of Merger
        with the Texas Secretary of State; (C) filings with, and approval of,
        the Nasdaq or the AMEX; (D) such filings and approvals as may be
        required by any applicable state securities, "blue sky" or takeover
        laws, or environmental laws; (E) such filings and approvals as may be
        required by any foreign premerger notification, securities, corporate or
        other law, rule or regulation; and (F) any such consent, approval,
        order, authorization, registration, declaration, filing, or permit that
        the failure to obtain or make would not, individually or in the
        aggregate, have a Material Adverse Effect on Midland, materially impair
        the ability of Midland to perform its obligations hereunder, or prevent
        the consummation of any of the transactions contemplated hereby.
 
          (d) SEC DOCUMENTS. Midland has made available to Vista a true and
     complete copy of each report, schedule, registration statement, and
     definitive proxy statement filed by Midland with the SEC since December 31,
     1995 and prior to or on the date of this Agreement (the "Midland SEC
     Documents"), which are all the documents (other than preliminary material)
     that Midland was required to file with the SEC between December 31, 1995
     and the date of this Agreement. As of their respective dates, the Midland
     SEC Documents complied in all material respects with the requirements of
     the Securities Act or the Exchange Act, as the case may be, and the rules
     and regulations of the SEC thereunder applicable to such Midland SEC
     Documents, and none of the Midland SEC Documents contained any untrue
     statement of a material fact or omitted to state a material fact required
     to be stated therein or necessary to make the statements therein, in light
     of the circumstances under which they were made, not misleading. The
     financial statements of Midland included in the Midland SEC Documents
     complied as to form in all material respects with the published rules and
     regulations of the SEC with respect thereto, were prepared in accordance
     with generally accepted accounting principles in the United States ("GAAP")
     applied on a consistent basis during the periods involved (except as may be
     indicated in the notes thereto or, in the case of the unaudited statements,
     as permitted by Rule 10-01 of Regulation S-X of the SEC) and fairly present
     in accordance with applicable requirements of GAAP (subject, in the case of
     the unaudited statements, to normal, recurring adjustments, none of which
     are material) the consolidated financial position of Midland and its
     consolidated Subsidiaries as of their respective dates and the consolidated
     results of operations and the consolidated cash flows of Midland and its
     consolidated Subsidiaries for the periods presented therein. In addition,
     Midland has made available to Vista the audited consolidated balance sheets
     of Midland and its Subsidiaries as of December 31, 1997, together with the
     audited consolidated statements of operations, shareholder's equity and
     cash flows of Midland and its Subsidiaries for the year then ended (such
     audited consolidated financial statements of Midland being referred to as
     the "Midland Financial Statements"). The Midland Financial Statements were
     prepared in accordance with GAAP applied on a consistent basis during the
     periods involved and fairly present in accordance with applicable
     requirements of GAAP the consolidated financial position of Midland and its
     consolidated Subsidiaries as of its date and the consolidated results of
     operations and the consolidated cash flows of Midland and its Subsidiaries
     for the period presented therein. Except as disclosed in the Midland SEC
     Documents, there are no agreements, arrangements, or understandings between
     Midland and any party who is at the date of this Agreement or was at any
     time prior to the date hereof but after December 31, 1995 an Affiliate of
     Midland that are required to be disclosed in the Midland SEC Documents.
 
          (e) INFORMATION SUPPLIED. None of the information supplied or to be
     supplied by Midland for inclusion or incorporation by reference in the
     Registration Statement on Form S-4 to be filed with the SEC by Newco in
     connection with the issuance of shares of Newco Common Stock in the Midland
     Merger (the "S-4") will, at the time the S-4 becomes effective under the
     Securities Act or at the Effective Time, contain any untrue statement of a
     material fact or omit to state any material fact required



                                      A-23
<PAGE>

     to be stated therein or necessary to make the statements therein not
     misleading, and none of the information supplied or to be supplied by
     Midland and included or incorporated by reference in the Proxy Statement
     will, at the date mailed to shareholders of Midland or at the time of the
     meeting of such shareholders to be held in connection with the Midland
     Merger or at the Effective Time, contain any untrue statement of a material
     fact or omit to state any material fact required to be stated therein or
     necessary in order to make the statements therein, in light of the
     circumstances under which they are made, not misleading. If at any time
     prior to the Effective Time any event with respect to Midland or any of its
     Subsidiaries, or with respect to other information supplied by Midland for
     inclusion in the Proxy Statement or S-4, shall occur which is required to
     be described in an amendment of, or a supplement to, the S-4 or the Proxy
     Statement, such event shall be so described, and such amendment or
     supplement shall be promptly filed with the SEC and, as required by law,
     disseminated to the shareholders of Midland. The Proxy Statement, insofar
     as it relates to Midland or its Subsidiaries or other information supplied
     by Midland for inclusion therein, will comply as to form in all material
     respects with the provisions of the Exchange Act and the rules and
     regulations thereunder.
 
          (f) ABSENCE OF CERTAIN CHANGES OR EVENTS. Except as disclosed in, or
     reflected in the financial statements included in the Midland SEC Documents
     or in the Midland Financial Statements, or except as contemplated by this
     Agreement, since December 31, 1997, there has not been: (i) any
     declaration, setting aside, or payment of any dividend or other
     distribution (whether in cash, stock or property) with respect to any of
     Midland's capital stock; (ii) any amendment of any material term of any
     outstanding equity security of Midland or any Subsidiary of Midland; (iii)
     any repurchase, redemption, or other acquisition by Midland or any
     Subsidiary of Midland of any outstanding shares of capital stock or other
     equity securities of, or other ownership interests in, Midland or any
     Subsidiary of Midland; (iv) any material change in any method of accounting
     or accounting practice or any tax method, practice, or election by Midland
     or any Subsidiary of Midland; or (v) any other transaction, commitment,
     dispute or other event or condition (financial or otherwise) of any
     character (whether or not in the ordinary course of business) that is
     reasonably likely to have a Material Adverse Effect on Midland, except for
     general economic changes and changes that may affect the industries of
     Midland or any of its Subsidiaries generally.
 
          (g) NO UNDISCLOSED MATERIAL LIABILITIES. Except as disclosed on
     Schedule 3.1(g)or as disclosed in the Midland SEC Documents or in the
     Midland Financial Statements, as of the date hereof, there are no
     liabilities of Midland or any of its Subsidiaries of any kind whatsoever,
     whether accrued, contingent, absolute, determined, determinable or
     otherwise, that are reasonably likely to have a Material Adverse Effect on
     Midland, other than: (i) liabilities adequately provided for on the balance
     sheet of Midland dated as of December 31, 1997 (including the notes
     thereto) contained in Midland's Annual Report on Form 10-KSB for the year
     ended December 31, 1997; (ii) liabilities incurred in the ordinary course
     of business subsequent to December 31, 1997; and (iii) liabilities under
     this Agreement.
 
          (h) NO DEFAULT. Except as disclosed on Schedule 3.1(h), neither
     Midland nor any of its Subsidiaries is in default or violation (and no
     event has occurred which, with notice or the lapse of time or both, would
     constitute a default or violation) of any term, condition or provision of
     (i) the Articles of Incorporation or Bylaws of Midland or the comparable
     charter or organizational documents of any of its Subsidiaries, (ii) any
     loan or credit agreement, note, bond, mortgage, indenture, lease, or other
     agreement, instrument, permit, concession, franchise, or license to which
     Midland or any of its Subsidiaries is now a party or by which Midland or
     any of its Subsidiaries or any of their respective properties or assets is
     bound or (iii) any order, writ, injunction, decree, statute, rule, or
     regulation applicable to Midland or any of its Subsidiaries, except in the
     case of clauses (ii) and (iii) in this subsection for defaults or
     violations which in the aggregate would not have a Material Adverse Effect
     on Midland.
 
          (i) COMPLIANCE WITH APPLICABLE LAWS. Midland and its Subsidiaries hold
     all permits, licenses, variances, exemptions, orders, franchises and
     approvals of all Governmental Entities necessary for the lawful conduct of
     their respective businesses (the "Midland Permits"), except where the
     failure so to hold would not have a Material Adverse Effect on Midland.
     Midland and its Subsidiaries are in

                                      A-24
<PAGE>

     compliance with the terms of the Midland Permits, except where the failure
     so to comply would not have a Material Adverse Effect on Midland. Except as
     disclosed in the Midland SEC Documents, the businesses of Midland and its
     Subsidiaries are not being conducted in violation of any law, ordinance, or
     regulation of any Governmental Entity, except for possible violations which
     would not have a Material Adverse Effect on Midland. As of the date of this
     Agreement, no investigation or review by any Governmental Entity with
     respect to Midland or any of its Subsidiaries is pending and of which
     Midland has knowledge or, to the knowledge (as hereinafter defined) of
     Midland as of the date hereof, threatened, other than those the outcome of
     which would not have a Material Adverse Effect on Midland.
 
          (j) LITIGATION. Except as disclosed in the Midland SEC Documents or
     Schedule 3.1(j) of the Midland Disclosure Schedule, as of the date of this
     Agreement there is no suit, action or proceeding pending, or, to the
     knowledge of Midland, threatened against or affecting Midland or any
     Subsidiary of Midland ("Midland Litigation"), and Midland and its
     Subsidiaries have no knowledge of any facts that are likely to give rise to
     any Midland Litigation, that (in any case) is reasonably likely to have a
     Material Adverse Effect on Midland, nor is there any judgment, decree,
     injunction, rule or order of any Governmental Entity or arbitrator
     outstanding against Midland or any Subsidiary of Midland ("Midland Order")
     that is reasonably likely to have a Material Adverse Effect on Midland or
     its ability to consummate the transactions contemplated by this Agreement.
     Schedule 3.1(j) of the Midland Disclosure Schedule contains an accurate and
     complete list of all suits, actions and proceedings pending or, to the
     knowledge of Midland, threatened against or affecting Midland or any of its
     Subsidiaries as of the date hereof.
 
          (k) TAXES. Except as set forth on Schedule 3.1(k) of the Midland
     Disclosure Schedule:
 
             (i) Each of Midland, each of its Subsidiaries and any affiliated,
        consolidated, combined, unitary or similar group of which Midland or any
        of its Subsidiaries is or was a member has (A) duly filed on a timely
        basis (taking into account any extensions) all U.S. federal income Tax
        Returns (as hereinafter defined), and all other material Tax Returns,
        required to be filed or sent by or with respect to it, (B) duly paid or
        deposited on a timely basis all Taxes (as hereinafter defined) that are
        shown to be due and payable on or with respect to such Tax Returns, and
        all material Taxes that are otherwise due and payable (except for audit
        adjustments not material in the aggregate or to the extent that
        liability therefor is reserved for in Midland's most recent audited
        financial statements) for which Midland or any of its Subsidiaries may
        be liable, (C) established reserves that are adequate for the payment of
        all material Taxes not yet due and payable with respect to the results
        of operations of Midland and its Subsidiaries through the date hereof,
        and (D) complied in all material respects with all applicable laws,
        rules and regulations relating to the reporting, payment and withholding
        of Taxes that are required to be withheld from payments to employees,
        independent contractors, creditors, shareholders or any other third
        party and has in all material respects timely withheld from employee
        wages and paid over to the proper governmental authorities all amounts
        required to be so withheld and paid over.
 
             (ii) Schedule 3.1(k) of the Midland Disclosure Schedule sets forth
        (A) the last taxable period through which the federal income Tax Returns
        of Midland and any of its Subsidiaries have been audited by the IRS or
        for which the statute of limitations for assessment has otherwise closed
        and (B) any affiliated, consolidated, combined, unitary or similar group
        or Tax Return in which Midland or any of its Subsidiaries is or has been
        a member or joins or has joined in the filing. Except to the extent
        being contested in good faith, all material deficiencies asserted as a
        result of such examinations and any examination by any applicable taxing
        authority have been paid, fully settled or adequately provided for in
        Midland's most recent audited financial statements. Except as disclosed
        in or adequately provided for in the Midland SEC Documents or disclosed
        in Schedule 3.1(k) of the Midland Disclosure Schedule, no audits or
        other administrative proceedings or court proceedings are presently
        pending, or to the knowledge of Midland, threatened, with regard to any
        Taxes for which Midland or any of its Subsidiaries would be liable, and
        no material deficiency for any Taxes has been proposed, asserted or
        assessed (whether by examination report or prior to completion of
        examination by means of notices of proposed adjustment or other similar
        requests or notices) pursuant to such
                                      A-25
<PAGE>
 
        examination against Midland or any of its Subsidiaries by any taxing
        authority with respect to any period.
 
             (iii) Neither Midland nor any of its Subsidiaries has executed or
        entered into with the IRS or any taxing authority (A) any agreement or
        other document extending or having the effect of extending the period
        for assessment or collection of any income or franchise Taxes for which
        Midland or any of its Subsidiaries would be liable or (B) a closing
        agreement pursuant to Section 7121 of the Code or any similar provision
        of state, local, foreign or other income tax law, which will require any
        increase in taxable income or alternative minimum taxable income, or any
        reduction in tax credits, for Midland or any of its Subsidiaries for any
        taxable period ending after the Closing Date.
 
             (iv) Except as set forth in the Midland SEC Documents or disclosed
        in Schedule 3.1(k), neither Midland nor any of its Subsidiaries is a
        party to an agreement that provides for the payment of any amount that
        would constitute a "parachute payment" within the meaning of Section
        280G of the Code or that would constitute compensation whose
        deductibility is limited under Section 162(m) of the Code.
 
             (v) Except as set forth in the Midland SEC Documents, neither
        Midland nor any of its Subsidiaries is a party to, is bound by or has
        any obligation under any tax sharing or allocation agreement or similar
        agreement or arrangement.
 
             (vi) There are no requests for rulings or outstanding subpoenas
        from any taxing authority for information with respect to Taxes of
        Midland or any of its Subsidiaries and, to the knowledge of Midland, no
        material reassessments (for property or ad valorem Tax purposes) of any
        assets or any property owned or leased by Midland or any of its
        Subsidiaries have been proposed in written form.
 
             (vii) Neither Midland nor any of its Subsidiaries has agreed to
        make any adjustment pursuant to Section 481(a) of the Code (or any
        predecessor provision) by reason of any change in any accounting method
        of Midland or any of its Subsidiaries, and neither Midland nor any of
        its Subsidiaries has any application pending with any taxing authority
        requesting permission for any changes in any accounting method of
        Midland or any of its Subsidiaries. To the knowledge of Midland, neither
        the IRS nor any other taxing authority has proposed in writing, and
        neither Midland nor any of its Subsidiaries is otherwise required to
        make, any such adjustment or change in accounting method.
 
             (viii) There are no material excess loss accounts or deferred
        intercompany transactions between Midland and/or any of its Subsidiaries
        within the meaning of Treas. Reg. Section 1.1502-13 or 1.1502-19,
        respectively.
 
          For purposes of this Agreement, "Tax" (and, with correlative meaning,
     "Taxes") means (i) any net income, alternative or add-on minimum tax, gross
     income, gross receipts, sales, use, ad valorem, value added, transfer,
     franchise, profits, license, withholding on amounts paid by Midland or any
     of its Subsidiaries (or Vista or any of its Subsidiaries, as applicable),
     payroll, employment, excise, production, severance, stamp, occupation,
     premium, property, environmental or windfall profit tax, custom, duty or
     other tax, governmental fee or other like assessment or charge of any kind
     whatsoever, together with any interest and/or any penalty, addition to tax
     or additional amount imposed by any taxing authority, (ii) any liability of
     Midland or any of its Subsidiaries (or Vista or any of its Subsidiaries, as
     applicable) for the payment of any amounts of the type described in (i) as
     a result of being a member of an affiliated or consolidated group, or
     arrangement whereby liability of Midland or any of its Subsidiaries (or
     Vista or any of its Subsidiaries, as applicable) for payment of such
     amounts was determined or taken into account with reference to the
     liability of any other person for any period and (iii) liability of Midland
     or any of its Subsidiaries (or Vista or any of its Subsidiaries, as
     applicable) with respect to the payment of any amounts of the type
     described in (i) or (ii) as a result of any express or implied obligation
     to indemnify any other Person.


                                      A-26
<PAGE>
 
          "Tax Return" means all returns, declarations, reports, estimates,
     information returns and statements required to be filed by or with respect
     to Midland or any of its Subsidiaries (or Vista or any of its Subsidiaries,
     as applicable) in respect of any Taxes, including, without limitation, (i)
     any consolidated Federal Income Tax return in which Midland or any of its
     Subsidiaries (or Vista or any of its Subsidiaries, as applicable) is
     included and (ii) any state, local or foreign Income Tax returns filed on a
     consolidated, combined or unitary basis (for purposes of determining tax
     liability) in which Midland or any of its Subsidiaries (or Vista or any of
     its Subsidiaries, as applicable) is included.
 
          (l) EMPLOYEE BENEFIT MATTERS. (i) Schedule 3.1(l)(i) provides a
     description of each of the following which is sponsored, maintained or
     contributed to by Midland or one of its Subsidiaries (the "Midland Group")
     for the benefit of the employees of the Midland Group, former employees of
     the Midland Group, directors of the Midland Group, former directors of the
     Midland Group, or any agents, consultants, or similar representatives
     providing services to or for the Midland Group, or has been so sponsored,
     maintained or contributed to within six years prior to the Closing Date for
     the benefit of such individuals:
 
             (A) each "employee benefit plan," as such term is defined in
        Section 3(3) of ERISA (including, but not limited to, employee benefit
        plans, such as foreign plans, which are not subject to the provisions of
        ERISA) ("Midland Plan");
 
             (B) except for the Midland Stock Option Plans, each personnel
        policy, stock option plan, stock purchase plan, stock appreciation
        rights, phantom stock plan, collective bargaining agreement, bonus plan
        or arrangement, incentive award plan or arrangement, vacation policy,
        severance pay plan, policy or agreement, deferred compensation agreement
        or arrangement, executive compensation or supplemental income
        arrangement, consulting agreement, employment agreement and each other
        employee benefit plan, agreement, arrangement, program, practice or
        understanding which is not described in Section 3.1(l)(i)(A) (together
        with the Midland Stock Plans, the "Midland Benefit Program or
        Agreement").
 
          (ii) True, correct and complete copies of each of the Midland Plans,
     related trusts, insurance or group annuity contracts and each other funding
     or financing arrangement relating to any Midland Plan, including all
     amendments thereto, have been furnished to Vista. There has also been
     furnished to Vista, with respect to each Midland Plan required to file such
     report and description, the most recent report on Form 5500 and the summary
     plan description. True, correct and complete copies or descriptions of all
     Midland Benefit Programs or Agreements have also been furnished to Vista. A
     schedule of employer expenses with respect to each Midland Plan and Midland
     Benefit Program or Agreement for the current plan year and past plan year
     has been furnished to Vista along with any administration agreement
     associated with any Midland Plan. Additionally, the most recent
     determination letter from the IRS for each of the Midland Plans intended to
     be qualified under Section 401 of the Code, and any outstanding
     determination letter application for such plans has been furnished.
 
          (iii) Except as otherwise set forth on Schedule 3.1(l)(iii),
 
             (A) Each Midland Plan and Midland Benefit Program or Agreement has
        been administered in compliance with its terms, the applicable
        provisions of ERISA, the Code and all other applicable laws and the
        terms of all applicable collective bargaining agreements;
 
             (B) There are no actions, suits or claims pending (other than
        routine claims for benefits) or, to the knowledge of a member of the
        Midland Group, threatened against, or with respect to, any of the
        Midland Plans or Midland Benefit Programs or Agreements or their assets;
 
             (C) As to any Midland Plan intended to be qualified under Section
        401 of the Code, there has been no termination or partial termination of
        the Midland Plan within the meaning of Section 411(d)(3) of the Code;
 
             (D) No act, omission or transaction has occurred which would result
        in imposition on a member of the Midland Group of (1) breach of
        fiduciary duty liability damages under Section 409


                                      A-27
<PAGE>
 
        of ERISA, (2) a civil penalty assessed pursuant to subsections (c), (i)
        or (l) of Section 502 of ERISA or (3) a tax imposed pursuant to Chapter
        43 of Subtitle D of the Code;
 
             (E) To the knowledge of a member of the Midland Group, there is no
        matter pending (other than routine qualification determination filings)
        with respect to any of the Midland Plans before the IRS, the Department
        of Labor or the PBGC;
 
             (F) No trust funding a Midland Plan is intended to be exempt from
        federal income taxation pursuant to Section 501(c)(9) of the Code;
 
          (iv) In connection with the consummation of the transaction
     contemplated by this Agreement, no payments have or will be made under the
     Midland Plans or Midland Benefit Programs or Agreements which, in the
     aggregate, would result in imposition of the sanctions imposed under
     Sections 280G and 4999 of the Code.
 
          (v) Except as otherwise set forth in Schedule 3.1(l)(v), no Midland
     Plan or Midland Benefit Program or Agreement provides retiree medical or
     retiree life insurance benefits to any person and a member of the Midland
     Group is not contractually or otherwise obligated (whether or not in
     writing) to provide any person with life insurance or medical benefits upon
     retirement or termination of employment, other than as required by the
     provisions of Section 601 through 608 of ERISA and Section 4980B of the
     Code. Additionally, each Midland Plan which is an "employee welfare benefit
     plan," as such term is defined in Section 3(1) of ERISA, may be
     unilaterally amended or terminated in its entirety without liability except
     as to benefits accrued thereunder prior to such amendment or termination.
 
          (vi) No Midland Plan is a multiemployer plan within the meaning of
     Section 3(37) of ERISA.
 
          (vii) Except for the Midland Stock Plans or as otherwise set forth in
     Schedule 3.1(l)(vii), no Midland Plan or Midland Benefit Program or
     Agreement provides that payments pursuant to such Midland Plan or Midland
     Benefit Program or Agreement may be made in securities of a member of the
     Midland Group or a Commonly Controlled Entity, nor does any trust
     maintained pursuant to any Midland Plan or Midland Benefit Program or
     Agreement hold any securities of a member of the Midland Group.
 
          (m) LABOR MATTERS. Except as set forth on Schedule 3.1(m) of the
     Midland Disclosure Schedule or in the Midland SEC Documents:
 
             (i) neither Midland nor any of its Subsidiaries is a party to any
        collective bargaining agreement or other current labor agreement with
        any labor union or organization, and there is no current union
        representation question involving employees of Midland or any of its
        Subsidiaries, nor does Midland or any of its Subsidiaries know of any
        activity or proceeding of any labor organization (or representative
        thereof) or employee group (or representative thereof) to organize any
        such employees;
 
             (ii) as of the date hereof, there is no unfair labor practice
        charge or grievance arising out of a collective bargaining agreement or
        other grievance procedure against Midland or any of its Subsidiaries
        pending, or, to the knowledge or Midland or any of its Subsidiaries,
        threatened, that has, or is reasonably likely to have, a Material
        Adverse Effect on Midland;
 
             (iii) as of the date hereof, there is no complaint, lawsuit or
        proceeding in any forum by or on behalf of any present or former
        employee, any applicant for employment or any classes of the foregoing
        alleging breach of any express or implied contract of employment, any
        law or regulation governing employment or the termination thereof or
        other discriminatory, wrongful or tortious conduct in connection with
        the employment relationship against Midland or any of its Subsidiaries
        pending, or, to the knowledge of Midland or any of its Subsidiaries,
        threatened, that has, or is reasonably likely to have, a Material
        Adverse Effect on Midland;
 
             (iv) Midland and each of its Subsidiaries are in compliance with
        all applicable laws respecting employment and employment practices,
        terms and conditions of employment, wages, hours of work


                                      A-28
<PAGE>
 
        and occupational safety and health, except for non-compliance that does
        not have, and is not reasonably likely to have, a Material Adverse
        Effect on Midland; and
 
             (v) as of the date hereof, there is no proceeding, claim, suit,
        action or governmental investigation pending or, to the knowledge of
        Midland or any of its Subsidiaries, threatened, in respect to which any
        current or former director, officer, employee or agent of Midland or any
        of its Subsidiaries is or may be entitled to claim indemnification from
        Midland or any of its Subsidiaries pursuant to the Articles of
        Incorporation or Bylaws of Midland or any provision of the comparable
        charter or organizational documents of any of its Subsidiaries, as
        provided in any indemnification agreement to which Midland or any
        Subsidiary of Midland is a party or pursuant to applicable law that has,
        or is reasonably likely to have, a Material Adverse Effect on Midland.
 
          (n) INTANGIBLE PROPERTY. Midland and its Subsidiaries possess or have
     adequate rights to use all material trademarks, trade names, patents,
     service marks, brand marks, brand names, computer programs, databases,
     industrial designs and copyrights necessary for the operation of the
     businesses of each of Midland and its Subsidiaries (collectively, the
     "Midland Intangible Property"), except where the failure to possess or have
     adequate rights to use such properties would not reasonably be expected to
     have a Material Adverse Effect on Midland. All of the Midland Intangible
     Property is owned or licensed by Midland or its Subsidiaries free and clear
     of any and all Liens, except those that are not reasonably likely to have a
     Material Adverse Effect on Midland, and neither Midland nor any such
     Subsidiary has forfeited or otherwise relinquished any Midland Intangible
     Property which forfeiture would result in a Material Adverse Effect on
     Midland. To the knowledge of Midland, the use of the Midland Intangible
     Property by Midland or its Subsidiaries does not, in any material respect,
     conflict with, infringe upon, violate or interfere with or constitute an
     appropriation of any right, title, interest or goodwill, including, without
     limitation, any intellectual property right, trademark, trade name, patent,
     service mark, brand mark, brand name, computer program, database,
     industrial design, copyright or any pending application therefor of any
     other person and there have been no claims made and neither Midland nor any
     of its Subsidiaries has received any notice of any claim or otherwise knows
     that any of the Midland Intangible Property is invalid or conflicts with
     the asserted rights of any other person or has not been used or enforced or
     has failed to have been used or enforced in a manner that would result in
     the abandonment, cancellation or unenforceability of any of the Midland
     Intangible Property, except for any such conflict, infringement, violation,
     interference, claim, invalidity, abandonment, cancellation or
     unenforceability that would not reasonably be expected to have a Material
     Adverse Effect on Midland.
 
          (o) ENVIRONMENTAL MATTERS.
 
             For purposes of this Agreement:
 
                (i) "Environmental Laws" means all federal, state and local laws
           (including common laws), rules, regulations, ordinances, orders,
           decrees of any Governmental Entity, whether now in existence or
           hereafter enacted and in effect at the time of Closing, relating to
           pollution or the protection of human health, safety or the
           environment of any jurisdiction in which the applicable party hereto
           owns or operates assets or conducts business or owned or operated
           assets or conducted business (whether or not through a predecessor
           entity) (including, without limitation, ambient air, surface water,
           groundwater, land surface, subsurface strata, natural resources or
           wildlife), including, without limitation, laws and regulations
           relating to Releases or threatened Releases of Hazardous Materials or
           otherwise relating to the manufacture, processing, distribution, use,
           treatment, storage, disposal, transport or handling of solid waste or
           Hazardous Materials, and any similar laws, rules, regulations,
           ordinances, orders and decrees of any foreign jurisdiction in which
           the applicable party hereto owns or operates assets or conducts
           business;
 
                (ii) "Hazardous Materials" means (A) any petroleum or petroleum
           products, radioactive materials (including naturally occurring
           radioactive materials), asbestos in any form that is or could become
           friable, urea formaldehyde foam insulation, polychlorinated biphenyls
           or trans-


                                      A-29
<PAGE>
 
           formers or other equipment that contain dielectric fluid containing
           polychlorinated biphenyls, (B) any chemicals, materials or substances
           which are now defined as or included in the definition of "solid
           wastes," "hazardous substances," "hazardous wastes," "hazardous
           materials," "extremely hazardous substances," "restricted hazardous
           wastes," "toxic substances" or "toxic pollutants," or words of
           similar import, under any Environmental Law and (C) any other
           chemical, material, substance or waste, exposure to which is now
           prohibited, limited or regulated under any Environmental Law in a
           jurisdiction in which Midland or any of its Subsidiaries operates
           (for purposes of Section 3.1(o)) or in which Vista or any of its
           Subsidiaries operates (for purposes of Section 3.2(o)).
 
                (iii) "Release" means any spill, effluent, emission, leaking,
           pumping, pouring, emptying, escaping, dumping, injection, deposit,
           disposal, discharge, dispersal, leaching or migration into the indoor
           or outdoor environment, or into or out of any property owned,
           operated or leased by the applicable party or its Subsidiaries; and
 
                (iv) "Remedial Action" means all actions, including, without
           limitation, any capital expenditures, required by a Governmental
           Entity or required under any Environmental Law, or voluntarily
           undertaken to (A) clean up, remove, treat, or in any other way
           ameliorate or address any Hazardous Materials or other substance in
           the indoor or outdoor environment; (B) prevent the Release or threat
           of Release, or minimize the further Release of any Hazardous Material
           so it does not endanger or threaten to endanger the public or
           employee health or welfare of the indoor or outdoor environment; (C)
           perform pre-remedial studies and investigations or post-remedial
           monitoring and care pertaining or relating to a Release; or (D) bring
           the applicable party into compliance with any Environmental Law.
 
                Except as disclosed on Schedule 3.1(o) of the Midland Disclosure
           Schedule:
 
                    (v) The operations of Midland and its Subsidiaries have been
               conducted, are and, as of the Closing Date, will be, in
               compliance with all Environmental Laws, except where the failure
               to so comply would not reasonably be expected to have a Material
               Adverse Effect on Midland;
 
                    (vi) Midland and its Subsidiaries have obtained and will
               maintain all permits, licenses and registrations, or applications
               relating thereto, and have made and will make all filings,
               reports and notices required under applicable Environmental Laws
               for the continued operations of their respective businesses,
               except such matters the lack or failure of which would not
               reasonably be expected to lead to a Material Adverse Effect on
               Midland;
 
                    (vii) Midland and its Subsidiaries are not subject to any
               outstanding written orders issued by, or contracts with, any
               Governmental Entity or other person respecting (A) Environmental
               Laws, (B) Remedial Action, (C) any Release or threatened Release
               of a Hazardous Material or (D) an assumption of responsibility
               for environmental liabilities of another person, except such
               orders or contracts the compliance with which would not
               reasonably be expected to have a Material Adverse Effect on
               Midland;
 
                    (viii) Midland and its Subsidiaries have not received any
               written communication alleging, with respect to any such party,
               the violation of or liability under any Environmental Law, which
               violation or liability would reasonably be expected to have a
               Material Adverse Effect on Midland;
 
                    (ix) Neither Midland nor any of its Subsidiaries has any
               contingent liability in connection with the Release of any
               Hazardous Material into the indoor or outdoor environment
               (whether on-site or off-site) or employee or third party exposure
               to Hazardous Materials that would reasonably be expected to lead
               to a Material Adverse Effect on Midland;
 
                    (x) The operations of Midland or its Subsidiaries involving
               the generation, transportation, treatment, storage or disposal of
               hazardous or solid waste, as defined and regulated

                                      A-30
<PAGE>
 
               under 40 C.F.R. Parts 260-270 (in effect as of the date of this
               Agreement) or any applicable state equivalent, are in compliance
               with applicable Environmental Laws, except where the failure to
               so comply would not reasonably be expected to have a Material
               Adverse Effect on Midland; and
 
                    (xi) To the knowledge of Midland, there is not now on or in
               any property of Midland or its Subsidiaries or any property for
               which Midland or its Subsidiaries is potentially liable any of
               the following: (A) any underground storage tanks or surface
               impoundments or (B) any on-site disposal of Hazardous Material,
               any of which ((A) or (B) preceding) could reasonably be expected
               to have a Material Adverse Effect on Midland.
 
          (p) INSURANCE. Schedule 3.1(p) of the Midland Disclosure Schedule sets
     forth an insurance schedule of Midland's and each of its Subsidiaries'
     directors' and officers' liability insurance, primary and excess casualty
     insurance policies, providing coverage for bodily injury and property
     damage to third parties, including products liability and completed
     operations coverage, and worker's compensation, in effect as of the date
     hereof. Midland maintains, and through the Closing Date will maintain,
     insurance in such amounts and covering such risks as are in accordance with
     normal industry practice for companies engaged in businesses similar to
     those of Midland and each of its Subsidiaries (taking into account the cost
     and availability of such insurance). Each of Midland and its Subsidiaries
     may terminate each of its insurance policies or binders at or after the
     Closing Date and will incur no penalties or other material costs in doing
     so. None of such policies or binders was obtained through the use of false
     or misleading information or the failure to provide the insurer with all
     information requested in order to evaluate the liabilities and risks
     insured. There is no material default with respect to any provision
     contained in any such policy or binder nor has Midland or any of its
     Subsidiaries failed to give any notice or present any claim under any such
     policy or binder in due and timely fashion. There are no billed but unpaid
     premiums past due under any such policy or binder. Except as otherwise
     disclosed on Schedule 3.1(p) of the Midland Disclosure Schedule, there are
     no outstanding claims under any such policies or binders and, to the
     knowledge of Midland, there has not occurred any event that might
     reasonably form the basis of any claim against or relating to Midland or
     any of its Subsidiaries is not covered by any of such policies or binders.
     No notice of cancellation or non-renewal of any such policies or binders
     has been received. Except as otherwise disclosed on Schedule 3.1(p) of the
     Midland Disclosure Schedule, there are no performance bonds outstanding
     with respect to Midland or any of its Subsidiaries.
 
          (q) ABSENCE OF CERTAIN CHANGES OR EVENTS. Except as disclosed on
     Schedule 3.1(q) of the Midland Disclosure Schedule or as contemplated by
     this Agreement, since December 31, 1997 none of Midland or any of its
     Subsidiaries has done any of the following:
 
             (i) Discharged or satisfied any Lien or paid any obligation or
        liability, absolute or contingent, other than current liabilities
        incurred and paid in the ordinary course of business and consistent with
        past practices;
 
             (ii) Paid or declared any dividends or distributions, purchased,
        redeemed, acquired, or retired any indebtedness, stock, or other
        securities from its shareholders or other securityholders, made any
        loans or advances or guaranteed any loans or advances to any Person
        (other than loans, advances, or guaranties made in the ordinary course
        of business and consistent with past practices), or otherwise incurred
        or suffered to exist any liabilities (other than current liabilities
        incurred in the ordinary course of business and consistent with past
        practices);
 
             (iii) Except for Permitted Encumbrances suffered or permitted any
        Lien to arise or be granted or created against or upon any of its
        assets;
 
             (iv) Cancelled, waived, or released any rights or claims against,
        or indebtedness owed by, third parties;
 
             (v) Amended its certificate or articles of incorporation or bylaws
        or comparable organizational documents;

                                      A-31
<PAGE>
 
             (vi) Made or permitted any amendment, supplement, modification, or
        termination of any Midland Material Agreement;
 
             (vii) Paid or made any agreement to pay any severance or
        termination payment to any employee or consultant;
 
             (viii) Sold, transferred, assigned, or otherwise disposed of (A)
        any Oil and Gas Interests of Midland that, individually or in the
        aggregate, had a value at the time of such transfer, assignment, or
        disposition of $50,000 or more or (B) any other assets (including any
        undeveloped leasehold acreage) that, individually or in the aggregate,
        had a value at the time of such transfer, assignment, or disposition of
        $50,000 or more; provided, however, that this paragraph shall not apply
        to Hydrocarbons sold in the ordinary course of business and consistent
        with past practices;
 
             (ix) Made any investment in or contribution, payment, or advance to
        any Person (other than investments, contributions, payments, or
        advances, or commitments with respect thereto, made in the ordinary
        course of business and consistent with past practices).
 
             (x) Granted present or future increases in the rates of
        compensation or other benefits payable to any of its directors,
        officers, or other executive personnel or any consultant or paid any
        bonuses to such Persons;
 
             (xi) Paid, loaned, or advanced (other than the payment, advance or
        reimbursement of expenses in the ordinary course of business) any
        amounts to, or sold, transferred, or leased any of its assets to, or
        entered into any other transactions with, any of its Affiliates;
 
             (xii) Waived any rights of material value;
 
             (xiii) Suffered any material damage, destruction, or loss, whether
        or not covered by insurance, affecting its assets or prospects;
 
             (xiv) Made any change in any of the accounting principles followed
        by it or the method of applying such principles;
 
             (xv) Suffered any material labor trouble or any material
        controversies with any of its employees or collective bargaining
        association representing any of its employees;
 
             (xvi) Entered into any other transactions (other than this
        Agreement) except in the ordinary course of business and consistent with
        past practices;
 
             (xvii) Taken any of the actions referred to in Section 4.1 except
        as would have been permitted or required thereby had such Section been
        applicable at the time of such action;
 
             (xviii) Agreed, whether in writing or otherwise, to do any of the
        foregoing; or
 
             (xix) Suffered any material adverse change or trend in its
        financial position, results of operations, or business (other than
        changes or trends, including changes or trends in commodity prices,
        generally prevalent in or affecting the oil and gas industry).
 
          (r) GOVERNMENTAL REGULATION. None of Midland or any of its
     Subsidiaries is subject to regulation under the Public Utility Holding
     Company Act of 1935, the Federal Power Act, the Interstate Commerce Act,
     the Investment Company Act of 1940, or any state public utilities code.
 
          (s) NO RESTRICTIONS. Except as otherwise disclosed on Schedule 3.1(s)
     of the Midland Disclosure Schedule, none of Midland or any of its
     Subsidiaries is a party to (i) any agreement, indenture, or other
     instrument that contains restrictions with respect to the payment of
     dividends or other distributions with respect to its capital, (ii) any
     financial arrangement with respect to or creating any indebtedness to any
     Person (other than indebtedness reflected in the Midland SEC Documents or
     indebtedness incurred in the ordinary course of business), (iii) any
     agreement, contract, or commitment relating to the making of any advance
     to, or investment in, any Person (other than advances in the ordinary
     course of business), (iv) any guaranty or other contingent liability with
     respect to any indebtedness or obligation of any

                                      A-32
<PAGE>
 
     Person (other than guaranties undertaken in the ordinary course of business
     and other than the endorsement of negotiable instruments for collection in
     the ordinary course of business), (v) any management, service, consulting,
     or other contract of a similar nature that cannot be terminated by Midland
     or any of its Subsidiaries, as the case may be, upon written notice of 30
     days or less and without penalty or other obligation, or (vi) any
     agreement, contract, or commitment limiting in any respect its ability to
     compete with any Person or otherwise conduct business of any line or
     nature.
 
          (t) AUDITS AND SETTLEMENTS. Except as otherwise disclosed on Schedule
     3.1(t) of the Midland Disclosure Schedule, none of Midland or any of its
     Subsidiaries is a party or subject to any unresolved or incomplete audit,
     accounting, or other settlement.
 
          (u) EMPLOYMENT CONTRACTS AND BENEFITS. Except as otherwise disclosed
     on Schedule 3.1(u) of the Midland Disclosure Schedule or otherwise provided
     for in any Midland Plan or Midland Benefit Program or Agreement, (i) none
     of Midland or any of its Subsidiaries is subject to or obligated under any
     consulting, employment, severance, termination, or similar arrangement, any
     employee benefit, incentive, deferred compensation plan with respect to any
     Person, or any bonus, profit sharing, pension, stock option, stock
     purchase, or similar plan or other arrangement or other fringe benefit plan
     entered into or maintained for the benefit of employees or any other Person
     and (ii) no employee of Midland or any of its Subsidiaries, or any other
     Person owns, or has any right granted by Midland or any of its Subsidiaries
     to acquire, any interest in any of the assets or business of Midland or any
     of its Subsidiaries.
 
          (v) ACCOUNTS RECEIVABLE. Except as otherwise disclosed on Schedule
     3.1(v) of the Midland Disclosure Schedule, all of the accounts, notes, and
     loans receivable that have been recorded on the books of Midland or any of
     its Subsidiaries are bona fide and represent accounts, notes, and loans
     receivable validly due for goods sold or services rendered and are
     reasonably expected to be collected in full within 90 days after the
     applicable invoice or note maturity date (other than such accounts, notes,
     and loans receivable that, individually or in the aggregate, do not have a
     book value as of the date hereof in excess of $25,000). Except for
     Permitted Encumbrances, all of such accounts, notes, and loans receivable
     are free and clear of any and all Liens and other adverse claims and
     charges, and none of such accounts, notes, or loans receivable is subject
     to any offsets or claims of offset. None of the obligors on such accounts,
     notes, or loans receivable has given notice to Midland or any of its
     Subsidiaries that it will or may refuse to pay the full amount or any
     portion thereof.
 
          (w) TITLE TO ASSETS. Midland and its Subsidiaries (individually or
     collectively) have Defensible Title to all Oil and Gas Interests of Midland
     included or reflected in the Midland Engineering Report or the Midland
     Financial Statements. Each Oil and Gas Interest included or reflected in
     the Midland Engineering Report entitles Midland and its Subsidiaries
     (individually or collectively) to receive not less than the undivided
     interest set forth in (or derived from) the Midland Engineering Report of
     all Hydrocarbons produced, saved, and sold from or attributable to such Oil
     and Gas Interest, and the portion of the costs and expenses of operation
     and development of such Oil and Gas Interest that is borne or to be borne
     by Midland and its Subsidiaries (individually or collectively) is not
     greater than the undivided interest set forth in (or derived from) the
     Midland Engineering Report. Except for Permitted Encumbrances, each of
     Midland and its Subsidiaries has good, marketable, and defensible title to
     its assets (other than the Oil and Gas Interests of Midland). All leases
     pursuant to which Midland or any of its Subsidiaries leases any assets are
     in full force and effect, and neither Midland or any of its Subsidiaries
     has received any notice of default under any such lease.
 
          (x) MIDLAND ENGINEERING REPORT. All information supplied to Williamson
     Petroleum Consultants, Inc. by or on behalf of Midland that was material to
     such firm's evaluation of Midland's Oil and Gas Interests in connection
     with the preparation of the Midland Engineering Report was (at the time
     supplied or as modified or amended prior to the issuance of the Midland
     Engineering Report) true and correct in all material respects. Except for
     changes in classification or values of oil and gas reserve or property
     interests that occurred in the ordinary course of business since December
     31, 1997 and except for changes (including changes in commodity prices)
     generally affecting the oil and gas industry, there has been no Material
     Adverse Change with respect to the matters addressed in the Midland
     Engineering Report.

                                      A-33
<PAGE>
 
          (y) OIL AND GAS OPERATIONS. Except as otherwise disclosed on Schedule
     3.1(y):
 
             (i) None of the wells included in the Oil and Gas Interests of
        Midland has been overproduced such that it is subject or liable to being
        shut-in or to any overproduction penalty, except where any such
        overproduction could not reasonably be expected to have a Material
        Adverse Effect on Midland;
 
             (ii) There have been no changes proposed in the production
        allowables for any wells included in the Oil and Gas Interests of
        Midland that could reasonably be expected to have a Material Adverse
        Effect on Midland;
 
             (iii) All wells included in the Oil and Gas Interests of Midland
        have been drilled and (if completed) completed, operated, and produced
        in accordance with good oil and gas field practices and in compliance in
        all material respects with applicable oil and gas leases and applicable
        laws, rules, and regulations, except where any failure or violation
        could not reasonably be expected to have a Material Adverse Effect on
        Midland;
 
             (iv) None of Midland or any of its Subsidiaries has agreed to or is
        now obligated to abandon any well operated by any of them and included
        in the Oil and Gas Interests of Midland that is or will not be abandoned
        and reclaimed in accordance with applicable laws, rules, and regulations
        and good oil and gas industry practices;
 
             (v) Proceeds from the sale of Hydrocarbons produced from and
        attributable to Midland's Oil and Gas Interests are being received by
        Midland or its Subsidiaries in a timely manner and are not being held in
        suspense for any reason (except for amounts, individually or in the
        aggregate, not in excess of $25,000 and held in suspense in the ordinary
        course of business); and
 
             (vi) No Person has any call on, option to purchase, or similar
        rights with respect to Midland's Oil and Gas Interests or to the
        production attributable thereto, and upon consummation of the
        transactions contemplated by this Agreement, Midland and its
        Subsidiaries will have the right to market production from Midland's Oil
        and Gas Interests on terms no less favorable than the terms upon which
        such company is currently marketing such production.
 
          (z) HYDROCARBON SALES AND PURCHASE AGREEMENTS. Except as otherwise
     disclosed on Schedule 3.1(z) of the Midland Disclosure Schedule:
 
             (i) None of the Hydrocarbon Sales Agreements of Midland or
        Hydrocarbon Purchase Agreements of Midland has required since December
        31, 1997, or will require as of or after the Closing Date, Midland or
        any of its Subsidiaries (A) to have sold or delivered, or to sell or
        deliver, Hydrocarbons for a price materially less than the market value
        price that would have been, or would be, received pursuant to any
        arm's-length contract for a term of one month with an unaffiliated
        third-party purchaser or (B) to have purchased or received, or to
        purchase or receive, Hydrocarbons for a price materially greater than
        the market value price that would have been, or would be, paid pursuant
        to an arm's-length contract for a term of one month with an unaffiliated
        third-party seller;
 
             (ii) Each of the Hydrocarbon Agreements of Midland is valid,
        binding, and in full force and effect, and no party is in material
        breach or default of any Hydrocarbon Agreement of Midland, and to the
        knowledge of Midland, no event has occurred that with notice or lapse of
        time (or both) would constitute a material breach or default or permit
        termination, modification, or acceleration under any Hydrocarbon
        Agreement of Midland;
 
             (iii) There have been no claims from any third party for any price
        reduction or increase or volume reduction or increase under any of the
        Hydrocarbon Agreements of Midland, and none of Midland or any of its
        Subsidiaries has made any claims for any price reduction or increase or
        volume reduction or increase under any of the Hydrocarbon Agreements of
        Midland;
 
             (iv) Payments for Hydrocarbons sold pursuant to each Hydrocarbon
        Sales Agreement of Midland have been made (subject to adjustment in
        accordance with such Hydrocarbon Sales

                                      A-34
<PAGE>
 
        Agreements) materially in accordance with prices or price setting
        mechanisms set forth in such Hydrocarbon Sales Agreements;
 
             (v) No purchaser under any Hydrocarbon Sales Agreement of Midland
        has notified Midland or any of its Subsidiaries (or, to the knowledge of
        Midland, the operator of any property) of its intent to cancel,
        terminate, or renegotiate any Hydrocarbon Sales Agreement of Midland or
        otherwise to fail and refuse to take and pay for Hydrocarbons in the
        quantities and at the price set out in any Hydrocarbon Sales Agreement,
        whether such failure or refusal was pursuant to any force majeure,
        market out, or similar provisions contained in such Hydrocarbon Sales
        Agreement or otherwise;
 
             (vi) None of Midland or any of its Subsidiaries is obligated in any
        Hydrocarbon Sales Agreement by virtue of any prepayment arrangement, a
        "take-or-pay" or similar provision, a production payment, or any other
        arrangements to deliver Hydrocarbons produced from an Oil and Gas
        Interest of Midland at some future time without then or thereafter
        receiving payment therefor;
 
             (vii) Midland and its Subsidiaries, collectively, are not
        obligated, due to production and pipeline gas imbalances, to deliver gas
        having a market value in excess of $50,000 without receiving payment
        therefor; and
 
             (viii) The Hydrocarbon Agreements of Midland are of the type
        generally found in the oil and gas industry, do not (individually or in
        the aggregate) contain unusual or unduly burdensome provisions that may
        have a Material Adverse Effect on Midland, and are in form and substance
        considered normal within the oil and gas industry.
 
          (aa) FINANCIAL AND COMMODITY HEDGING. Schedule 3.1(aa) of the Midland
     Disclosure Schedule accurately summarizes the outstanding Hydrocarbon and
     financial hedging positions of Midland and its Subsidiaries (including
     fixed price controls, collars, swaps, caps, hedges, and puts).
 
          (bb) COMMITTED CAPITAL EXPENDITURES. Schedule 3.1(bb) of the Midland
     Disclosure Schedule is a true, accurate, and complete list of all
     commitments (including AFEs) pursuant to which Midland or any of its
     Subsidiaries has paid or incurred since December 31, 1997, or is obligated
     to pay or incur after the date hereof, drilling or capital expenditures in
     excess of $25,000 with respect to any well, and except as otherwise
     disclosed on Schedule 3.1(bb) of the Midland Disclosure Schedule, the
     aggregate amount of drilling and capital expenditures with respect to oil
     and gas wells that Midland and its Subsidiaries have paid or incurred since
     December 31, 1997 or are obligated to pay or incur after the date hereof
     does not exceed $500,000.
 
          (cc) BUSINESS RELATIONS. To the knowledge of Midland, since December
     31, 1997, there has been no termination, cancellation, or limitation of, or
     any material modification or change in, the material business relationships
     of Midland or any of its Subsidiaries with any material supplier or
     customer or any partner or joint venture partner nor has there been any
     material development relating to any such supplier, customer, partner, or
     joint venture partner that could reasonably be expected to have a Material
     Adverse Effect on Midland.
 
          (dd) BOOKS AND RECORDS. All books, records, and files of Midland and
     its Subsidiaries (including those pertaining to Midland's Oil and Gas
     Interests, wells, and other assets, those pertaining to the production,
     gathering, transportation, and sale of Hydrocarbons, and corporate,
     accounting, financial, and employee records) (i) have been prepared,
     assembled, and maintained in accordance with usual and customary policies
     and procedures and (ii) fairly and accurately reflect the ownership, use,
     enjoyment, and operation by Midland and its Subsidiaries of their
     respective assets.
 
          (ee) BROKERS. Except as disclosed in Schedule 3.1(ee), no broker,
     finder, investment banker, or other Person is or will be, in connection
     with the transactions contemplated by this Agreement, entitled to any
     brokerage, finder's, or other fee or compensation based on any arrangement
     or agreement made by or on behalf of Midland and for which Newco, Midland
     or any Subsidiary of Midland.
 

                                      A-35
<PAGE>
 
          (ff) VOTE REQUIRED. The affirmative vote of the holders of at least
     two-thirds of the outstanding shares of Midland Common Stock is the only
     vote of the holders of any class or series of Midland capital stock or
     other voting securities necessary to approve this Agreement, the Midland
     Merger, and the transactions contemplated hereby.
 
          (gg) DISCLOSURE AND INVESTIGATION. No representation or warranty of
     Midland contained in this Agreement contains any untrue statement of a
     material fact or omits to state a material fact necessary in order to make
     the statements contained herein not misleading. The Responsible Officers,
     individually or collectively, of Midland and its Subsidiaries have
     conducted, or have caused the respective officers, employees,
     representatives, or agents of Midland and its Subsidiaries to conduct, such
     investigations and inquiries that they reasonably believe most likely to
     confirm the truth and accuracy of each of the representations and
     warranties contained in this Section.
 
          (hh) FAIRNESS OPINION. Midland has received an oral opinion from Dain
     Rauscher Incorporated to the effect that the consideration to be received
     in the Midland Merger by the holders of shares of Midland Common Stock is
     fair to such holders from a financial point of view and such opinion has
     not been withdrawn, revoked, or modified.
 
     3.2 REPRESENTATIONS AND WARRANTIES OF VISTA. Vista hereby represents and
warrants to Midland as follows:
 
          (a) ORGANIZATION, STANDING AND POWER. Each of Vista, the General
     Partner and Vista Sub is a partnership or corporation duly organized,
     validly existing and in good standing under the laws of its state of
     incorporation, has all requisite power and authority to own, lease, and
     operate its properties and to carry on its business as now being conducted,
     and is duly qualified and in good standing to do business in each
     jurisdiction in which the business it is conducting, or the operation,
     ownership, or leasing of its properties, makes such qualification
     necessary, other than in such jurisdictions where the failure so to qualify
     would not have a Material Adverse Effect on Vista. Vista has heretofore
     delivered to Midland complete and correct copies of its Agreement of
     Limited Partnership, as amended to date. The jurisdiction of incorporation
     of the General Partner and Vista Sub is Texas. Vista has no Subsidiary
     other than Vista Sub.
 
          (b) CAPITAL STRUCTURE.
 
             (i) All outstanding Partnership Interests are validly issued and
        all capital contributions required to be made with respect to such
        Partnership Interests have been made in full. The outstanding
        Partnership Interests are subject to preemptive rights as set forth in
        the Agreement of Limited Partnership. The outstanding Partnership
        Interests have not been issued in violation of such preemptive rights.
        Except as set forth in this Section 3.2(b), the Agreement of Limited
        Partnership, or on Schedule 3.2(b) of the Vista Disclosure Schedule,
        there are outstanding: (1) no Partnership Interests, Voting Debt or
        other voting securities of Vista; (2) no securities of Vista or Vista
        Sub convertible into or exchangeable for Partnership Interests, Voting
        Debt or other voting securities of Vista or Vista Sub; and (3) no
        options, warrants, calls, rights (including preemptive rights),
        commitments, or agreements to which Vista or Vista Sub is a party or by
        which it is bound in any case obligating Vista or Vista Sub to issue,
        deliver, sell, purchase, redeem or acquire, or cause to be issued,
        delivered, sold, purchased, redeemed or acquired, additional Partnership
        Interests or any Voting Debt or other voting securities of Vista or of
        Vista Sub, or obligating Vista or Vista Sub to grant, extend, or enter
        into any such option, warrant, call, right, commitment, or agreement.
        Except for the Agreement of Limited Partnership, there are not as of the
        date hereof and there will not be at the Effective Time any voting
        trusts or other agreements or understandings to which Vista is a party
        or by which it is bound relating to the voting of any Partnership
        Interests that will limit in any way the solicitation of consents by or
        on behalf of Vista from, or the casting of votes by, the partners of
        Vista with respect to the Vista Exchange. All outstanding shares of
        capital stock of Vista Sub are owned by Vista, free and clear of all
        Liens. There are no restrictions on Vista to vote the capital stock of
        Vista Sub


                                      A-36
<PAGE>
 
             (ii) As of the date hereof, the authorized capital stock of the
        General Partner consists of 100,000 shares of GP Common Stock. At the
        close of business on April 30, 1998, 79,254 shares of GP Common Stock
        were issued and outstanding and no shares of GP Common Stock are held by
        the General Partner in its treasury. No shares of GP Common Stock are
        reserved for issuance for any other purpose. No Voting Debt on any
        matters on which shareholders of the General Partner may vote are issued
        and outstanding. All outstanding shares of GP Common Stock are validly
        issued, fully paid, and nonassessable and are not subject to preemptive
        rights. Except as described above, there are outstanding (A) no shares
        of GP Common Stock, Voting Debt or other voting securities of the
        General Partner; (B) no securities of the General Partner convertible
        into or exchangeable for shares of GP Common Stock, Voting Debt or other
        voting securities of the General Partner; and (C) no options, warrants,
        calls, rights (including preemptive rights), commitments, or agreements
        to which the General Partner is a party or by which it is bound in any
        case obligating the General Partner to issue, deliver, sell, purchase,
        redeem or acquire, or cause to be issued, delivered, sold, purchased,
        redeemed or acquired, additional shares of GP Common Stock or any Voting
        Debt or other voting securities of the General Partner, or obligating
        the General Partner to grant, extend, or enter into any such option,
        warrant, call, right, commitment, or agreement.
 
          (c) AUTHORITY; NO VIOLATIONS; CONSENTS AND APPROVALS.
 
             (i) The General Partner has approved the Vista Exchange and this
        Agreement, and declared the Vista Exchange and this Agreement to be in
        the best interests of the shareholders of the General Partner and the
        limited partners of Vista. Vista has all requisite partnership power and
        authority to enter into this Agreement. The execution and delivery of
        this Agreement and the consummation of the transactions contemplated
        hereby have been duly authorized by all necessary corporate action on
        the part of the General Partner and all necessary partnership action on
        the part of Vista. This Agreement has been duly executed and delivered
        by Vista and, assuming this Agreement constitutes the valid and binding
        obligation of Midland, Newco, and Merger Sub, constitutes a valid and
        binding obligation of Vista enforceable in accordance with its terms,
        subject, as to enforceability, to bankruptcy, insolvency,
        reorganization, moratorium and other laws of general applicability
        relating to or affecting creditors' rights and to general principles of
        equity (regardless of whether such enforceability is considered in a
        proceeding in equity or at law).
 
             (ii) Except as set forth on Schedule 3.2(c) of the Vista Disclosure
        Schedule, the execution and delivery of this Agreement does not, and the
        consummation of the transactions contemplated hereby and compliance with
        the provisions hereof will not, conflict with, or result in any
        violation of, or default (with or without notice or lapse of time, or
        both) under, or give rise to a right of termination, cancellation, or
        acceleration of any material obligation or to the loss of a material
        benefit under, or give rise to a right of purchase under, result in the
        creation of any Lien upon any of the properties or assets of Vista, the
        General Partner or Vista Sub under, or otherwise result in a material
        detriment to Vista, the General Partner or Vista Sub under, any
        provision of (A) the Agreement of Limited Partnership or any provision
        of the Articles of Incorporation or Bylaws the General Partner or Vista
        Sub, (B) any loan or credit agreement, note, bond, mortgage, indenture,
        lease, or other agreement, instrument, permit, concession, franchise, or
        license applicable to Vista, the General Partner or Vista Sub, (C) any
        joint venture or other ownership arrangement, or (D) any judgment,
        order, decree, statute, law, ordinance, rule, or regulation applicable
        to Vista, the General Partner or Vista Sub or any of their respective
        properties or assets, other than, in the case of clause (B) or (C) in
        this subsection, any such conflicts, violations, defaults, rights, Liens
        that, individually or in the aggregate, would not have a Material
        Adverse Effect on Vista, materially impair the ability of Vista to
        perform its obligations hereunder, or prevent the consummation of any of
        the transactions contemplated hereby.
 
             (iii) No consent, approval, order or authorization of, or
        registration, declaration or filing with, or permit from any
        Governmental Entity, is required by or with respect to Vista, the
        General Partner or Vista Sub in connection with the execution and
        delivery of this Agreement by Vista or the consummation by Vista of the
        transactions contemplated hereby, as to which the failure to obtain or


                                      A-37
<PAGE>
 
        make would have a Material Adverse Effect on Vista, except for (A) such
        filings and approvals as may be required by any applicable state
        securities, "blue sky" or takeover laws, or environmental laws; (B) such
        filings and approvals as may be required by any foreign premerger
        notification, securities, corporate or other law, rule or regulation;
        and (C) any such consent, approval, order, authorization, registration,
        declaration, filing, or permit that the failure to obtain or make would
        not, individually or in the aggregate, have a Material Adverse Effect on
        Vista, materially impair the ability of Vista to perform its obligations
        hereunder, or prevent the consummation of any of the transactions
        contemplated hereby.
 
          (d) FINANCIAL STATEMENTS AND MATERIAL AGREEMENTS. Vista has made
     available to Midland a true and complete copy of (i) each of the Vista
     Material Agreements and (ii) the audited consolidated balance sheets of
     Vista and its sole Subsidiary as of December 31, 1997, together with the
     audited consolidated statements of operations, partners' capital, and cash
     flows of Vista and its sole Subsidiary for the year then ended, and the
     notes thereto, accompanied by the reports thereon of Arthur Andersen LLP
     (such audited consolidated financial statements of Vista collectively being
     referred to as the "Financial Statements"). The Financial Statements were
     prepared in accordance with GAAP applied on a consistent basis during the
     periods involved (except as may be indicated in the notes thereto) and
     fairly present in accordance with applicable requirements of GAAP the
     consolidated financial position of Vista and its consolidated sole
     Subsidiary as of their respective dates and the consolidated results of
     operations and the consolidated cash flows of Vista and its sole Subsidiary
     for year then ended.
 
          (e) INFORMATION SUPPLIED. None of the information supplied or to be
     supplied by Vista for inclusion or incorporation by reference in the S-4 to
     be filed with the SEC by Newco in connection with the issuance of shares of
     Newco Common Stock in the Midland Merger will, at the time the S-4 becomes
     effective under the Securities Act or at the Effective Time, contain any
     untrue statement of a material fact or omit to state any material fact
     required to be stated therein or necessary to make the statements therein
     not misleading, and none of the information supplied or to be supplied by
     Vista and included or incorporated by reference in the Proxy Statement
     will, at the date mailed to shareholders of Midland or at the time of the
     meeting of such shareholders to be held in connection with the Midland
     Merger or at the Effective Time, contain any untrue statement of a material
     fact or omit to state any material fact required to be stated therein or
     necessary in order to make the statements therein, in light of the
     circumstances under which they are made, not misleading. If at any time
     prior to the Effective Time any event with respect to Vista, the General
     Partner or Vista Sub, or with respect to other information supplied by
     Vista for inclusion in the Proxy Statement or S-4, shall occur which is
     required to be described in an amendment of, or a supplement to, the S-4 or
     the Proxy Statement, such event shall be so described, and such amendment
     or supplement shall be promptly filed with the SEC.
 
          (f) ABSENCE OF CERTAIN CHANGES OR EVENTS. Except as disclosed in, or
     reflected in the Financial Statements, or except as contemplated by this
     Agreement, since December 31, 1997, there has not been: (i) any
     declaration, setting aside, or payment of any distribution (whether in
     cash, stock or property) with respect to any of Vista's equity securities;
     (ii) any amendment of any material term of any outstanding equity security
     of Vista, the General Partner or Vista Sub; (iii) any repurchase,
     redemption, or other acquisition by Vista, the General Partner or Vista Sub
     of any outstanding shares of capital stock, Partnership Interests, or other
     equity securities of, or other ownership interests in, Vista, the General
     Partner or Vista Sub; (iv) any material change in any method of accounting
     or accounting practice or any tax method, practice, or election by Vista,
     the General Partner or Vista Sub; or (v) any other transaction, commitment,
     dispute or other event or condition (financial or otherwise) of any
     character (whether or not in the ordinary course of business) that is
     reasonably likely to have a Material Adverse Effect on Vista, except for
     general economic changes and changes that may affect the industries of
     Vista, the General Partner or Vista Sub generally.
 
          (g) NO UNDISCLOSED MATERIAL LIABILITIES. Except as disclosed in the
     Financial Statements, as of the date hereof, there are no liabilities of
     Vista, the General Partner or Vista Sub of any kind whatsoever, whether
     accrued, contingent, absolute, determined, determinable or otherwise, that
     are reasonably likely

                                      A-38
<PAGE>
 
     to have a Material Adverse Effect on Vista, other than: (i) liabilities
     adequately provided for on the consolidated balance sheet of Vista and its
     sole Subsidiary dated as of December 31, 1997 (including the notes
     thereto), a copy of which has previously been provided to Midland; (ii)
     liabilities incurred in the ordinary course of business subsequent to
     December 31, 1997; and (iii) liabilities under this Agreement. The General
     Partner has not engaged in any business, operations or activities other
     than business, operations and activities undertaken in its capacity as
     general partner of Vista.
 
          (h) NO DEFAULT. Neither Vista, the General Partner nor Vista Sub is in
     default or violation (and no event has occurred which, with notice or the
     lapse of time or both, would constitute a default or violation) of any
     term, condition or provision of (i) the Agreement of Limited Partnership or
     the Articles of Incorporation and Bylaws of the General Partner or Vista
     Sub, (ii) any loan or credit agreement, note, bond, mortgage, indenture,
     lease, or other agreement, instrument, permit, concession, franchise, or
     license to which Vista, the General Partner or Vista Sub is now a party or
     by which Vista, the General Partner or Vista Sub or any of their respective
     properties or assets is bound, or (iii) any order, writ, injunction,
     decree, statute, rule or regulation applicable to Vista, the General
     Partner or Vista Sub, except in the case of clauses (ii) and (iii) in this
     subsection for defaults or violations which in the aggregate would not have
     a Material Adverse Effect on Vista.
 
          (i) COMPLIANCE WITH APPLICABLE LAWS. Vista, the General Partner and
     Vista Sub hold all permits, licenses, variances, exemptions, orders,
     franchises and approvals of all Governmental Entities necessary for the
     lawful conduct of their respective businesses (the "Vista Permits"), except
     where the failure so to hold would not have a Material Adverse Effect on
     Vista. Vista, the General Partner and Vista Sub are in compliance with the
     terms of the Vista Permits, except where the failure so to comply would not
     have a Material Adverse Effect on Vista. The businesses of Vista, the
     General Partner and Vista Sub are not being conducted in violation of any
     law, ordinance, or regulation of any Governmental Entity, except for
     possible violations which would not have a Material Adverse Effect on
     Vista. As of the date of this Agreement, no investigation or review by any
     Governmental Entity with respect to Vista, the General Partner and Vista
     Sub is pending and of which Vista has knowledge or, to the knowledge of
     Vista as of the date hereof, threatened, other than those the outcome of
     which would not have a Material Adverse Effect on Vista.
 
          (j) LITIGATION. Except as disclosed on Schedule 3.2(j) of the Vista
     Disclosure Schedule, as of the date of this Agreement there is no suit,
     action or proceeding pending, or, to the knowledge of Vista, threatened
     against or affecting Vista, the General Partner or Vista Sub ("Vista
     Litigation"), and Vista, the General Partner and Vista Sub have no
     knowledge of any facts that are likely to give rise to any Vista
     Litigation, that (in any case) is reasonably likely to have a Material
     Adverse Effect on Vista, nor is there any judgment, decree, injunction,
     rule or order of any Governmental Entity or arbitrator outstanding against
     Vista, the General Partner or Vista Sub ("Vista Order") that is reasonably
     likely to have a Material Adverse Effect on Vista or its ability to
     consummate the transactions contemplated by this Agreement. Schedule 3.2(j)
     of the Vista Disclosure Schedule contains an accurate and complete list of
     all suits, actions and proceedings pending or, to the knowledge of Vista,
     threatened against or affecting Vista, the General Partner or Vista Sub as
     of the date hereof.
 
          (k) TAXES. Except as set forth on Schedule 3.2(k) of the Vista
     Disclosure Schedule:
 
             (i) Each of Vista, the General Partner and Vista Sub and any
        affiliated, consolidated, combined, unitary or similar group of which
        Vista, the General Partner and Vista Sub is or was a member has (A) duly
        filed on a timely basis (taking into account any extensions) all U.S.
        federal income Tax Returns, and all other material Tax Returns, required
        to be filed or sent by or with respect to it, (B) duly paid or deposited
        on a timely basis all Taxes that are shown to be due and payable on or
        with respect to such Tax Returns, and all material Taxes that are
        otherwise due and payable (except for audit adjustments not material in
        the aggregate or to the extent that liability therefor is reserved for
        in Vista's most recent audited financial statements) for which Vista,
        the General Partner or Vista Sub may be liable, (C) established reserves
        that are adequate for the payment of all material Taxes not yet due and
        payable with respect to the results of operations of

                                      A-39
<PAGE>
 
        Vista, the General Partner and Vista Sub through the date hereof, and
        (D) complied in all material respects with all applicable laws, rules
        and regulations relating to the reporting, payment and withholding of
        Taxes that are required to be withheld from payments to employees,
        independent contractors, creditors, shareholders or any other third
        party and has in all material respects timely withheld from employee
        wages and paid over to the proper governmental authorities all amounts
        required to be so withheld and paid over.
 
             (ii) Schedule 3.2(k) of the Vista Disclosure Schedule sets forth
        (A) the last taxable period through which the federal income Tax Returns
        of Vista, the General Partner and Vista Sub have been audited by the IRS
        or for which the statute of limitations for assessment has otherwise
        closed and (B) any affiliated, consolidated, combined, unitary or
        similar group or Tax Return in which Vista, the General Partner or Vista
        Sub is or has been a member or joins or has joined in the filing. Except
        to the extent being contested in good faith, all material deficiencies
        asserted as a result of such examinations and any examination by any
        applicable taxing authority have been paid, fully settled or adequately
        provided for in Vista's most recent audited financial statements. Except
        as disclosed in Schedule 3.2(k) of the Vista Disclosure Schedule, no
        audits or other administrative proceedings or court proceedings are
        presently pending, or to the knowledge of Vista, threatened, with regard
        to any Taxes for which Vista, the General Partner or Vista Sub would be
        liable, and no material deficiency for any Taxes has been proposed,
        asserted or assessed (whether by examination report or prior to
        completion of examination by means of notices of proposed adjustment or
        other similar requests or notices) pursuant to such examination against
        Vista, the General Partner or Vista Sub by any taxing authority with
        respect to any period.
 
             (iii) Neither Vista, the General Partner nor Vista Sub has executed
        or entered into (or prior to the close of business on the Closing Date
        will execute or enter into) with the IRS or any taxing authority (A) any
        agreement or other document extending or having the effect of extending
        the period for assessment or collection of any income or franchise Taxes
        for which Vista, the General Partner or Vista Sub would be liable or (B)
        a closing agreement pursuant to Section 7121 of the Code or any similar
        provision of state, local, foreign or other income tax law, which will
        require any increase in taxable income or alternative minimum taxable
        income, or any reduction in tax credits, for Vista, the General Partner
        or Vista Sub for any taxable period ending after the Closing Date.
 
             (iv) Except as disclosed in Schedule 3.2(k) of the Vista Disclosure
        Schedule, neither Vista, the General Partner nor Vista Sub is a party to
        an agreement that provides for the payment of any amount that would
        constitute a "parachute payment" within the meaning of Section 280G of
        the Code or that would constitute compensation whose deductibility is
        limited under Section 162(m) of the Code.
 
             (v) Except as disclosed in Schedule 3.2(k) of the Vista Disclosure
        Schedule, neither Vista, the General Partner nor Vista Sub is a party
        to, is bound by or has any obligation under any tax sharing or
        allocation agreement or similar agreement or arrangement.
 
             (vi) There are no requests for rulings or outstanding subpoenas
        from any taxing authority for information with respect to Taxes of
        Vista, the General Partner or Vista Sub and, to the knowledge of Vista,
        no material reassessments (for property or ad valorem Tax purposes) of
        any assets or any property owned or leased by Vista, the General Partner
        or Vista Sub have been proposed in written form.
 
             (vii) Neither Vista, the General Partner nor Vista Sub has agreed
        to make any adjustment pursuant to Section 481(a) of the Code (or any
        predecessor provision) by reason of any change in any accounting method
        of Vista or any of its Subsidiaries, and neither Vista, the General
        Partner nor Vista Sub has any application pending with any taxing
        authority requesting permission for any changes in any accounting method
        of Vista, the General Partner or Vista Sub To the knowledge of Vista,
        neither the IRS nor any other taxing authority has proposed in writing,
        and neither Vista, the General Partner nor Vista Sub is otherwise
        required to make, any such adjustment or change in accounting method.


                                      A-40
<PAGE>
 
             (viii) Vista has properly qualified to be treated as a partnership
        for federal (and, where permissible, state) income Tax purposes and has
        not, at any time, been required to be taxed as an association taxable as
        a corporation for federal income Tax purposes under any provision of the
        Code or elected to be taxable as a corporation for federal income Tax
        purposes.
 
          (l) EMPLOYEE BENEFIT MATTERS. (i) Schedule 3.2(l)(i) provides a
     description of each of the following which is sponsored, maintained or
     contributed to by Vista, the General Partner, or Vista Sub (the "Vista
     Group") for the benefit of the employees of the Vista Group, former
     employees of the Vista Group, directors of the Vista Group, former
     directors of the Vista Group, or any agents, consultants, or similar
     representatives providing services to or for the Vista Group, or has been
     so sponsored, maintained or contributed to within six years prior to the
     Closing Date for the benefit of such individuals:
 
             (A) each "employee benefit plan," as such term is defined in
        Section 3(3) of ERISA (including, but not limited to, employee benefit
        plans, such as foreign plans, which are not subject to the provisions of
        ERISA) ("Vista Plan");
 
             (B) each personnel policy, stock option plan, stock purchase plan,
        stock appreciation rights, phantom stock plan, collective bargaining
        agreement, bonus plan or arrangement, incentive award plan or
        arrangement, vacation policy, severance pay plan, policy or agreement,
        deferred compensation agreement or arrangement, executive compensation
        or supplemental income arrangement, consulting agreement, employment
        agreement and each other employee benefit plan, agreement, arrangement,
        program, practice or understanding which is not described in Section
        3.2(l)(i)(A) ("Vista Benefit Program or Agreement").
 
          (ii) True, correct and complete copies of each of the Vista Plans,
     related trusts, insurance or group annuity contracts and each other funding
     or financing arrangement relating to any Vista Plan, including all
     amendments thereto, have been furnished to Midland. There has also been
     furnished to Midland, with respect to each Vista Plan required to file such
     report and description, the most recent report on Form 5500 and the summary
     plan description. True, correct and complete copies or descriptions of all
     Vista Benefit Programs or Agreements have also been furnished to Midland. A
     schedule of employer expenses with respect to each Vista Plan or Vista
     Benefit Program or Agreement for the current plan year and past plan year
     has been furnished to Midland along with any administration agreement
     associated with any Vista Plan. Additionally, the most recent determination
     letter from the IRS for each of the Vista Plans intended to be qualified
     under Section 401 of the Code, and any outstanding determination letter
     application for such plans has been furnished.
 
          (iii) Except as otherwise set forth on Schedule 3.2(l)(iii),
 
             (A) Each Vista Plan or Vista Benefit Program or Agreement has been
        administered in compliance with its terms, the applicable provisions of
        ERISA, the Code and all other applicable laws and the terms of all
        applicable collective bargaining agreements;
 
             (B) There are no actions, suits or claims pending (other than
        routine claims for benefits) or, to the knowledge of a member of the
        Vista Group, threatened against, or with respect to, any of the Vista
        Plans or Vista Benefit Programs or Agreements or their assets;
 
             (C) As to any Vista Plan intended to be qualified under Section 401
        of the Code, there has been no termination or partial termination of the
        Vista Plan within the meaning of Section 411(d)(3) of the Code;
 
             (D) No act, omission or transaction has occurred which would result
        in imposition on a member of the Vista Group of (1) breach of fiduciary
        duty liability damages under Section 409 of ERISA, (2) a civil penalty
        assessed pursuant to subsections (c), (i) or (l) of Section 502 of ERISA
        or (3) a tax imposed pursuant to Chapter 43 of Subtitle D of the Code;


                                      A-41
<PAGE>
 
             (E) To the knowledge of a member of the Vista Group, there is no
        matter pending (other than routine qualification determination filings)
        with respect to any of the Vista Plans before the IRS, the Department of
        Labor or the PBGC;
 
             (F) No trust funding a Vista Plan is intended to be exempt from
        federal income taxation pursuant to Section 501(c)(9) of the Code;
 
          (iv) In connection with the consummation of the transaction
     contemplated by this Agreement, no payments have or will be made under the
     Vista Plans or Vista Benefit Programs or Agreements which, in the
     aggregate, would result in imposition of the sanctions imposed under
     Sections 280G and 4999 of the Code.
 
          (v) Except as otherwise set forth in Schedule 3.2(l)(v), no Vista Plan
     or Vista Benefit Program or Agreement provides retiree medical or retiree
     life insurance benefits to any person and a member of the Vista Group is
     not contractually or otherwise obligated (whether or not in writing) to
     provide any person with life insurance or medical benefits upon retirement
     or termination of employment, other than as required by the provisions of
     Section 601 through 608 of ERISA and Section 4980B of the Code.
     Additionally, each Vista Plan which is an "employee welfare benefit plan,"
     as such term is defined in Section 3(1) of ERISA, may be unilaterally
     amended or terminated in its entirety without liability except as to
     benefits accrued thereunder prior to such amendment or termination.
 
          (vi) No Vista Plan is a multiemployer plan within the meaning of
     Section 3(37) of ERISA.
 
          (vii) Except as otherwise set forth in Schedule 3.2(l)(vii), no Vista
     Plan or Vista Benefit Program or Agreement provides that payments pursuant
     to such Vista Plan or Vista Benefit Program or Agreement may be made in
     securities of a member of the Vista Group or a Commonly Controlled Entity,
     nor does any trust maintained pursuant to any Vista Plan or Vista Benefit
     Program or Agreement hold any securities of a member of the Vista Group.
 
          (m) LABOR MATTERS. Except as set forth on Schedule 3.2(m) of the Vista
     Disclosure Schedule:
 
             (i) neither Vista, the General Partner nor Vista Sub is a party to
        any collective bargaining agreement or other current labor agreement
        with any labor union or organization, and there is no current union
        representation question involving employees of Vista, the General
        Partner or Vista Sub, nor does Vista, the General Partner or Vista Sub
        know of any activity or proceeding of any labor organization (or
        representative thereof) or employee group (or representative thereof) to
        organize any such employees;
 
             (ii) as of the date hereof, there is no unfair labor practice
        charge or grievance arising out of a collective bargaining agreement or
        other grievance procedure against Vista, the General Partner or Vista
        Sub pending, or, to the knowledge of Vista, the General Partner or Vista
        Sub, threatened, that has, or is reasonably likely to have, a Material
        Adverse Effect on Vista;
 
             (iii) as of the date hereof, there is no complaint, lawsuit or
        proceeding in any forum by or on behalf of any present or former
        employee, any applicant for employment or any classes of the foregoing
        alleging breach of any express or implied contract of employment, any
        law or regulation governing employment or the termination thereof or
        other discriminatory, wrongful or tortious conduct in connection with
        the employment relationship against Vista, the General Partner or Vista
        Sub pending, or, to the knowledge of Vista, the General Partner or Vista
        Sub, threatened, that has, or is reasonably likely to have, a Material
        Adverse Effect on Vista;
 
             (iv) Vista, the General Partner and Vista Sub are in compliance
        with all applicable laws respecting employment and employment practices,
        terms and conditions of employment, wages, hours of work and
        occupational safety and health, except for non-compliance that does not
        have, and is not reasonably likely to have, a Material Adverse Effect on
        Vista; and
 
             (v) As of the date hereof, there is no proceeding, claim, suit,
        action or governmental investigation pending or, to the knowledge of
        Vista, the General Partner or Vista Sub, threatened, in

                                      A-42
<PAGE>
 
        respect to which any current or former director, officer, employee or
        agent of Vista, the General Partner or Vista Sub is or may be entitled
        to claim indemnification from Vista, the General Partner or Vista Sub
        pursuant to the Agreement of Limited Partnership or any provision of the
        Articles of Incorporation or Bylaws of the General Partner or Vista Sub,
        as provided in any indemnification agreement to which Vista, the General
        Partner or Vista Sub is a party or pursuant to applicable law that has,
        or is reasonably likely to have, a Material Adverse Effect on Vista.
 
          (n) INTANGIBLE PROPERTY. Vista, the General Partner and Vista Sub
     possess or have adequate rights to use all material trademarks, trade
     names, patents, service marks, brand marks, brand names, computer programs,
     databases, industrial designs and copyrights necessary for the operation of
     the businesses of each of Vista, the General Partner and Vista Sub
     (collectively, the "Vista Intangible Property"), except where the failure
     to possess or have adequate rights to use such properties would not
     reasonably be expected to have a Material Adverse Effect on Vista. All of
     the Vista Intangible Property is owned or licensed by Vista, the General
     Partner or Vista Sub free and clear of any and all Liens, except those that
     are not reasonably likely to have a Material Adverse Effect on Vista, and
     neither Vista, the General Partner nor Vista Sub has forfeited or otherwise
     relinquished any Vista Intangible Property which forfeiture would result in
     a Material Adverse Effect on Vista. To the knowledge of Vista, the use of
     the Vista Intangible Property by Vista, the General Partner or Vista Sub
     does not, in any material respect, conflict with, infringe upon, violate or
     interfere with or constitute an appropriation of any right, title, interest
     or goodwill, including, without limitation, any intellectual property
     right, trademark, trade name, patent, service mark, brand mark, brand name,
     computer program, database, industrial design, copyright or any pending
     application therefor of any other person and there have been no claims made
     and neither Vista, the General Partner nor Vista Sub has received any
     notice of any claim or otherwise knows that any of the Vista Intangible
     Property is invalid or conflicts with the asserted rights of any other
     person or has not been used or enforced or has failed to have been used or
     enforced in a manner that would result in the abandonment, cancellation or
     unenforceability of any of the Vista Intangible Property, except for any
     such conflict, infringement, violation, interference, claim, invalidity,
     abandonment, cancellation or unenforceability that would not reasonably be
     expected to have a Material Adverse Effect on Vista.
 
          (o) ENVIRONMENTAL MATTERS. Except as disclosed on Schedule 3.2(o) of
     the Vista Disclosure Schedule:
 
             (i) The operations of Vista, the General Partner and Vista Sub have
        been conducted, are and, as of the Closing Date, will be, in compliance
        with all Environmental Laws, except where the failure to so comply would
        not reasonably be expected to have a Material Adverse Effect on Vista;
 
             (ii) Vista, the General Partner and Vista Sub have obtained and
        will maintain all permits, licenses and registrations, or applications
        relating thereto, and have made and will make all filings, reports and
        notices required under applicable Environmental Laws for the continued
        operations of their respective businesses, except such matters the lack
        or failure of which would not reasonably be expected to lead to a
        Material Adverse Effect on Vista;
 
             (iii) Vista, the General Partner and Vista Sub are not subject to
        any outstanding written orders issued by, or contracts with, any
        Governmental Entity or other person respecting (A) Environmental Laws,
        (B) Remedial Action, (C) any Release or threatened Release of a
        Hazardous Material or (D) an assumption of responsibility for
        environmental liabilities of another person, except such orders or
        contracts the compliance with which would not reasonably be expected to
        have a Material Adverse Effect on Vista;
 
             (iv) Vista, the General Partner and Vista Sub have not received any
        written communication alleging, with respect to any such party, the
        violation of or liability under any Environmental Law, which violation
        or liability would reasonably be expected to have a Material Adverse
        Effect on Vista;
 
             (v) Neither Vista, the General Partner nor Vista Sub has any
        contingent liability in connection with the Release of any Hazardous
        Material into the indoor or outdoor environment (whether on-

                                      A-43
<PAGE>
 
        site or off-site) or employee or third party exposure to Hazardous
        Materials that would reasonably be expected to lead to a Material
        Adverse Effect on Vista;
 
             (vi) The operations of Vista, the General Partner or Vista Sub
        involving the generation, transportation, treatment, storage or disposal
        of hazardous or solid waste, as defined and regulated under 40 C.F.R.
        Parts 260-270 (in effect as of the date of this Agreement) or any
        applicable state equivalent, are in compliance with applicable
        Environmental Laws, except where the failure to so comply would not
        reasonably be expected to have a Material Adverse Effect on Vista; and
 
             (vii) To the knowledge of Vista, there is not now on or in any
        property of Vista, the General Partner or Vista Sub or any property for
        which Vista, the General Partner or Vista Sub is potentially liable any
        of the following: (A) any underground storage tanks or surface
        impoundments or (B) any on-site disposal of Hazardous Material, any of
        which ((A) or (B) preceding) could reasonably be expected to have a
        Material Adverse Effect on Vista.
 
          (p) INSURANCE. Schedule 3.2(p) of the Vista Disclosure Schedule sets
     forth an insurance schedule of Vista's, the General Partner's and Vista
     Sub's directors' and officers' liability insurance, primary and excess
     casualty insurance policies, providing coverage for bodily injury and
     property damage to third parties, including products liability and
     completed operations coverage, and worker's compensation, in effect as of
     the date hereof. Vista maintains, and through the Closing Date will
     maintain, insurance in such amounts and covering such risks as are in
     accordance with normal industry practice for companies engaged in
     businesses similar to those of Vista, the General Partner and Vista Sub
     (taking into account the cost and availability of such insurance). Each of
     Vista, the General Partner and Vista Sub may terminate each of its
     insurance policies or binders at or after the Closing Date and will incur
     no penalties or other material costs in doing so. None of such policies or
     binders was obtained through the use of false or misleading information or
     the failure to provide the insurer with all information requested in order
     to evaluate the liabilities and risks insured. There is no material default
     with respect to any provision contained in any such policy or binder nor
     has Vista, the General Partner or Vista Sub failed to give any notice or
     present any claim under any such policy or binder in due and timely
     fashion. There are no billed but unpaid premiums past due under any such
     policy or binder. Except as otherwise disclosed on Schedule 3.2(p) of the
     Vista Disclosure Schedule, there are no outstanding claims under any such
     policies or binders and, to the knowledge of Vista, there has not occurred
     any event that might reasonably form the basis of any claim against or
     relating to Vista, the General Partner or Vista Sub that is not covered by
     any of such policies or binders. No notice of cancellation or non-renewal
     of any such policies or binders has been received. Except as otherwise
     disclosed on Schedule 3.2(p) of the Vista Disclosure Schedule, there are no
     performance bonds outstanding with respect to Vista, the General Partner or
     Vista Sub.
 
          (q) ABSENCE OF CERTAIN CHANGES OR EVENTS. Except as otherwise
     disclosed on Schedule 3.2(q) of the Vista Disclosure Schedule or as
     contemplated by this Agreement, since December 31, 1997, neither Vista, the
     General Partner nor Vista Sub has done any of the following:
 
             (i) Discharged or satisfied any Lien or paid any obligation or
        liability, absolute or contingent, other than current liabilities
        incurred and paid in the ordinary course of business and consistent with
        past practices;
 
             (ii) Paid or declared any dividends or distributions, purchased,
        redeemed, acquired, or retired any indebtedness, stock, or other
        securities from its partners, shareholders, or other securityholders,
        made any loans or advances or guaranteed any loans or advances to any
        Person (other than loans, advances, or guaranties made in the ordinary
        course of business and consistent with past practices), or otherwise
        incurred or suffered to exist any liabilities (other than current
        liabilities incurred in the ordinary course of business and consistent
        with past practices);
 
             (iii) Except for Permitted Encumbrances, suffered or permitted any
        Lien to arise or be granted or created against or upon any of its
        assets;

                                      A-44
<PAGE>
 
             (iv) Cancelled, waived, or released any rights or claims against,
        or indebtedness owed by, third parties;
 
             (v) Amended the Agreement of Limited Partnership, in the case of
        Vista, or its articles of incorporation or bylaws, in the case of the
        General Partner and Vista Sub;
 
             (vi) Made or permitted any amendment, supplement, modification, or
        termination of any Vista Material Agreement;
 
             (vii) Paid or made any agreement to pay any severance or
        termination payment to any employee or consultant;
 
             (viii) Sold, transferred, assigned, or otherwise disposed of (A)
        any Oil and Gas Interests of Vista that, individually or in the
        aggregate, had a value at the time of such transfer, assignment, or
        disposition of $50,000 or more or (B) any other assets (including any
        undeveloped leasehold acreage) that, individually or in the aggregate,
        had a value at the time of such transfer, assignment, or disposition of
        $50,000 or more provided, however, that this paragraph shall not apply
        to Hydrocarbons sold in the ordinary course of business and consistent
        with past practices;
 
             (ix) Made any investment in or contribution, payment, or advance to
        any Person (other than investments, contributions, payments, or
        advances, or commitments with respect thereto, made in the ordinary
        course of business and consistent with past practices).
 
             (x) Granted present or future increases in the rates of
        compensation or other benefits payable to any of its directors,
        officers, or other executive personnel or any consultant or paid any
        bonuses to such Persons;
 
             (xi) Paid, loaned, or advanced (other than the payment, advance or
        reimbursement of expenses in the ordinary course of business) any
        amounts to, or sold, transferred, or leased any of its assets to, or
        entered into any other transactions with, any of its Affiliates;
 
             (xii) Waived any rights of material value;
 
             (xiii) Suffered any material damage, destruction, or loss, whether
        or not covered by insurance, affecting its assets or prospects;
 
             (xiv) Made any change in any of the accounting principles followed
        by it or the method of applying such principles;
 
             (xv) Suffered any material labor trouble or any material
        controversies with any of its employees or collective bargaining
        association representing any of its employees;
 
             (xvi) Entered into any other transactions (other than this
        Agreement) except in the ordinary course of business and consistent with
        past practices;
 
             (xvii) Taken any of the actions referred to in Section 4.1 except
        as would have been permitted or required thereby had such Section been
        applicable at the time of such action;
 
             (xviii) Agreed, whether in writing or otherwise, to do any of the
        foregoing; or
 
             (xix) Suffered any material adverse change or trend in its
        financial position, results of operations, or business (other than
        changes or trends, including changes or trends in commodity prices,
        generally prevalent in or affecting the oil and gas industry).
 
          (r) GOVERNMENTAL REGULATION. Neither Vista, the General Partner nor
     Vista Sub is subject to regulation under the Public Utility Holding Company
     Act of 1935, the Federal Power Act, the Interstate Commerce Act, the
     Investment Company Act of 1940, or any state public utilities code.
 
          (s) NO RESTRICTIONS. Except for the Agreement of Limited Partnership
     or as otherwise disclosed on Schedule 3.2(s) of the Vista Disclosure
     Schedule, neither Vista, the General Partner nor Vista Sub is a party to
     (i) any agreement, indenture, or other instrument that contains
     restrictions with respect to the

                                      A-45
<PAGE>
 
     payment of dividends or other distributions with respect to its capital,
     (ii) any financial arrangement with respect to or creating any indebtedness
     to any Person (other than indebtedness reflected in the Financial
     Statements or indebtedness incurred in the ordinary course of business),
     (iii) any agreement, contract, or commitment relating to the making of any
     advance to, or investment in, any Person (other than advances in the
     ordinary course of business), (iv) any guaranty or other contingent
     liability with respect to any indebtedness or obligation of any Person
     (other than guaranties undertaken in the ordinary course of business and
     other than the endorsement of negotiable instruments for collection in the
     ordinary course of business), (v) any management, service, consulting, or
     other contract of a similar nature that cannot be terminated by Vista, the
     General Partner or Vista Sub, as the case may be, upon written notice of 30
     days or less and without penalty or other obligation, or (vi) any
     agreement, contract, or commitment limiting in any respect its ability to
     compete with any Person or otherwise conduct business of any line or
     nature.
 
          (t) AUDITS AND SETTLEMENTS. Except as otherwise disclosed on Schedule
     3.2(t) of the Vista Disclosure Schedule, neither Vista, the General Partner
     nor Vista Sub is a party or subject to any unresolved or incomplete audit,
     accounting, or other settlement.
 
          (u) EMPLOYMENT CONTRACTS AND BENEFITS. Except as otherwise disclosed
     on Schedule 3.2(u) of the Vista Disclosure Schedule or otherwise provided
     for in any Vista Plan or Vista Benefit Program or Agreement, (i) neither
     Vista, the General Partner nor Vista Sub is subject to or obligated under
     any consulting, employment, severance, termination, or similar arrangement,
     any employee benefit, incentive, or deferred compensation plan with respect
     to any Person, or any bonus, profit sharing, pension, stock option, stock
     purchase, or similar plan or other arrangement or other fringe benefit plan
     entered into or maintained for the benefit of employees or any other Person
     and (ii) no employee of Vista, the General Partner, Vista Sub, or any other
     Person owns, or has any right granted by Vista, the General Partner or
     Vista Sub to acquire, any interest in any of the assets or business of
     Vista, the General Partner or Vista Sub.
 
          (v) ACCOUNTS RECEIVABLE. Except as otherwise disclosed on Schedule
     3.2(v) of the Vista Disclosure Schedule, all of the accounts, notes, and
     loans receivable that have been recorded on the books of Vista, the General
     Partner or Vista Sub are bona fide and represent accounts, notes, and loans
     receivable validly due for goods sold or services rendered and are
     reasonably expected to be collected in full within 90 days after the
     applicable invoice or note maturity date (other than such accounts, notes,
     and loans receivable that, individually or in the aggregate, do not have a
     book value as of the date hereof in excess of $25,000). Except for
     Permitted Encumbrances, all of such accounts, notes, and loans receivable
     are free and clear of any and all Liens and other adverse claims and
     charges, and none of such accounts, notes, or loans receivable is subject
     to any offsets or claims of offset. None of the obligors on such accounts,
     notes, or loans receivable has given notice to Vista, the General Partner
     or Vista Sub that it will or may refuse to pay the full amount or any
     portion thereof.
 
          (w) TITLE TO ASSETS. Vista and Vista Sub (individually or
     collectively) have Defensible Title to all Oil and Gas Interests of Vista
     included or reflected in the Vista Engineering Report or the Financial
     Statements. Each Oil and Gas Interest included or reflected in the Vista
     Engineering Report entitles Vista and Vista Sub (individually or
     collectively) to receive not less than the undivided interest set forth in
     (or derived from) the Vista Engineering Report of all Hydrocarbons
     produced, saved, and sold from or attributable to such Oil and Gas
     Interest, and the portion of the costs and expenses of operation and
     development of such Oil and Gas Interest that is borne or to be borne by
     Vista and Vista Sub (individually or collectively) is not greater than the
     undivided interest set forth in (or derived from) the Vista Engineering
     Report. Except for Permitted Encumbrances, each of Vista and Vista Sub has
     good, marketable, and defensible title to its assets (other than the Oil
     and Gas Interests of Vista). All leases pursuant to which Vista or Vista
     Sub lease any assets are in full force and effect, and neither Vista nor
     Vista Sub has received any notice of default under any such lease.
 
          (x) VISTA ENGINEERING REPORT. All information supplied to Williamson
     Petroleum Consultants, Inc. by or on behalf of Vista that was material to
     such firm's evaluation of Vista's Oil and Gas Interests in connection with
     the preparation of the Vista Engineering Report was (at the time supplied
     or as modified

                                      A-46
<PAGE>
 
     or amended prior to the issuance of the Vista Engineering Report) true and
     correct in all material respects. Except for changes in classification or
     values of oil and gas reserve or property interests that occurred in the
     ordinary course of business since December 31, 1997 and except for changes
     (including changes in commodity prices) generally affecting the oil and gas
     industry, there has been no Material Adverse Change with respect to the
     matters addressed in the Vista Engineering Report.
 
          (y) OIL AND GAS OPERATIONS. Except as otherwise disclosed on Schedule
     3.2(y):
 
             (i) None of the wells included in the Oil and Gas Interests of
        Vista has been overproduced such that it is subject or liable to being
        shut-in or to any owe overproduction penalty, except where any such
        overproduction could not reasonably be expected to have a Material
        Adverse Effect on Vista;
 
             (ii) There have been no changes proposed in the production
        allowables for, any wells included in the Oil and Gas Interests of Vista
        that could reasonably be expected to have a Material Adverse Effect on
        Vista;
 
             (iii) All wells included in the Oil and Gas Interests of Vista have
        been drilled and (if completed) completed, operated, and produced in
        accordance with good oil and gas field practices and in compliance in
        all material respects with applicable oil and gas leases and applicable
        laws, rules, and regulations, except where any failure or violation
        could not reasonably be expected to have a Material Adverse Effect on
        Vista;
 
             (iv) Neither Vista nor Vista Sub has agreed to or is now obligated
        to abandon any well operated by any of them and included in the Oil and
        Gas Interests of Vista that is or will not be abandoned and reclaimed in
        accordance with applicable laws, rules, and regulations and good oil and
        gas industry practices;
 
             (v) Proceeds from the sale of Hydrocarbons produced from and
        attributable to Vista's Oil and Gas Interests are being received by
        Vista or Vista Sub in a timely manner and are not being held in suspense
        for any reason (except for amounts, individually or in the aggregate,
        not in excess of $25,000 and held in suspense in the ordinary course of
        business); and
 
             (vi) No Person has any call on, option to purchase, or similar
        rights with respect to Vista's Oil and Gas Interests or to the
        production attributable thereto, and upon consummation of the
        transactions contemplated by this Agreement, Vista or Vista Sub will
        have the right to market production from Vista's Oil and Gas Interests
        on terms no less favorable than the terms upon which such company is
        currently marketing such production.
 
          (z) HYDROCARBON SALES AND PURCHASE AGREEMENTS. Except as otherwise
     disclosed on Schedule 3.2(z) of the Vista Disclosure Schedule:
 
             (i) None of the Hydrocarbon Sales Agreements of Vista or
        Hydrocarbon Purchase Agreements of Vista has required since December 31,
        1997, or will require as of or after the Closing Date, Vista or Vista
        Sub (A) to have sold or delivered, or to sell or deliver, Hydrocarbons
        for a price materially less than the market value price that would have
        been, or would be, received pursuant to any arm's-length contract for a
        term of one month with an unaffiliated third-party purchaser or (B) to
        have purchased or received, or to purchase or receive, Hydrocarbons for
        a price materially greater than the market value price that would have
        been, or would be, paid pursuant to an arm's-length contract for a term
        of one month with an unaffiliated third-party seller;
 
             (ii) Each of the Hydrocarbon Agreements of Vista is valid, binding,
        and in full force and effect, and no party is in material breach or
        default of any Hydrocarbon Agreement of Vista, and to the knowledge of
        Vista, no event has occurred that with notice or lapse of time (or both)
        would constitute a material breach or default or permit termination,
        modification, or acceleration under any Hydrocarbon Agreement of Vista;


                                      A-47
<PAGE>
 
             (iii) There have been no claims from any third party for any price
        reduction or increase or volume reduction or increase under any of the
        Hydrocarbon Agreements of Vista, and neither Vista nor Vista Sub has
        made any claims for any price reduction or increase or volume reduction
        or increase under any of the Hydrocarbon Agreements of Vista;
 
             (iv) Payments for Hydrocarbons sold pursuant to each Hydrocarbon
        Sales Agreement of Vista have been made (subject to adjustment in
        accordance with such Hydrocarbon Sales Agreements) materially in
        accordance with prices or price setting mechanisms set forth in such
        Hydrocarbon Sales Agreements;
 
             (v) No purchaser under any Hydrocarbon Sales Agreement of Vista has
        notified Vista or Vista Sub (or, to the knowledge of Vista, the operator
        of any property) of its intent to cancel, terminate, or renegotiate any
        Hydrocarbon Sales Agreement of Vista or otherwise to fail and refuse to
        take and pay for Hydrocarbons in the quantities and at the price set out
        in any Hydrocarbon Sales Agreement, whether such failure or refusal was
        pursuant to any force majeure, market out, or similar provisions
        contained in the Hydrocarbon Sales Agreement or otherwise;
 
             (vi) Neither Vista nor Vista Sub is obligated in any Hydrocarbon
        Sales Agreement of Vista by virtue of any prepayment arrangement, a
        "take-or-pay" or similar provision, a production payment, or any other
        arrangements to deliver Hydrocarbons produced from an Oil and Gas
        Interest of Midland at some future time without then or thereafter
        receiving payment therefor;
 
             (vii) Vista and Vista Sub, collectively, are not obligated, due to
        production and pipeline gas imbalances, to deliver gas having a market
        value in excess of $50,000 without receiving payment therefor; and
 
             (viii) The Hydrocarbon Agreements of Vista are of the type
        generally found in the oil and gas industry, do not (individually or in
        the aggregate) contain unusual or unduly burdensome provisions that may
        have a Material Adverse Effect on Vista, and are in form and substance
        considered normal within the oil and gas industry.
 
          (aa) FINANCIAL AND COMMODITY HEDGING. Schedule 3.2(aa) of the Vista
     Disclosure Schedule accurately summarizes the outstanding Hydrocarbon and
     financial hedging positions of Vista and Vista Sub (including fixed price
     controls, collars, swaps, caps, hedges, and puts).
 
          (bb) COMMITTED CAPITAL EXPENDITURES. Schedule 3.2(bb) of the Vista
     Disclosure Schedule is a true, accurate, and complete list of all
     commitments (including AFEs) pursuant to which Vista or Vista Sub has paid
     or incurred since December 31, 1997, or is obligated to pay or incur after
     the date hereof, drilling or capital expenditures in excess of $25,000 with
     respect to any well, and except as otherwise set forth disclosed on
     Schedule 3.2(bb) of the Vista Disclosure Schedule, the aggregate amount of
     drilling and capital expenditures with respect to oil and gas wells that
     Vista and Vista Sub have paid or incurred since December 31, 1997 or are
     obligated to pay or incur after the date hereof does not exceed $500,000.
 
          (cc) BUSINESS RELATIONS. To the knowledge of Vista, since December 31,
     1997, there has been no termination, cancellation, or limitation of, or any
     material modification or change in, the material business relationships of
     Vista, the General Partner or Vista Sub with any material supplier or
     customer or any partner or joint venture partner nor has there been any
     material development relating to any such supplier, customer, partner, or
     joint venture partner that could reasonably be expected to have a Material
     Adverse Effect on Vista.
 
          (dd) BOOKS AND RECORDS. All books, records, and files of Vista, the
     General Partner and Vista Sub (including those pertaining to Vista's Oil
     and Gas Interests, wells, and other assets, those pertaining to the
     production, gathering, transportation, and sale of Hydrocarbons, and
     corporate, accounting, financial, and employee records) (i) have been
     prepared, assembled, and maintained in accordance with usual and customary
     policies and procedures and (ii) fairly and accurately reflect the
     ownership, use, enjoyment, and operation by Vista, the General Partner and
     Vista Sub of their respective assets.


                                      A-48
<PAGE>
 
          (ee) BROKERS. No broker, finder, investment banker, or other Person is
     or will be, in connection with the transactions contemplated by this
     Agreement, entitled to any brokerage, finder's, or other fee or
     compensation based on any arrangement or agreement made by or on behalf of
     Vista.
 
          (ff) DISCLOSURE AND INVESTIGATION. No representation or warranty of
     Vista contained in this Agreement contains any untrue statement of a
     material fact or omits to state a material fact necessary in order to make
     the statements contained herein not misleading. The Responsible Officers,
     individually or collectively, of Vista have conducted, or have caused the
     respective officers, employees, representatives, or agents of Vista, the
     General Partner and Vista Sub to conduct, such investigations and inquiries
     that they reasonably believe most likely to confirm the truth and accuracy
     of each of the representations and warranties contained in this Section.
 
     3.3 REPRESENTATIONS AND WARRANTIES OF NEWCO AND MERGER SUB. Newco, Merger
Sub and Vista, jointly and severally, represent and warrant to Midland as
follows:
 
          (a) ORGANIZATION, STANDING AND CORPORATE POWER. Each of Newco and
     Merger Sub is a corporation duly organized, validly existing and in good
     standing under the laws of the its state of incorporation has all requisite
     corporate power and authority to own, lease, and operate its properties and
     to carry on its business as now being conducted and is duly qualified and
     in good standing to do business in each jurisdiction in which the business
     it is conducting, or the operation, ownership or leasing of its properties,
     makes such qualification necessary, other than in such jurisdictions where
     the failure so to qualify would not have a Material Adverse Effect on Newco
     or Merger Sub, as applicable. Merger Sub has heretofore delivered to
     Midland complete and correct copies of its Articles of Incorporation and
     Bylaws. Complete and correct copies of Newco's Certificate of Incorporation
     and Bylaws are attached as Exhibit 3.3(a) hereto.
 
          (b) CAPITAL STRUCTURE.
 
             (i) As of the date hereof, the authorized capital stock of Newco
        consists of (x) 50,000,000 shares of common stock, $0.01 par value,
        1,000 shares of which are issued and outstanding, all of which are owned
        of record and beneficially by Vista and (y) 10,000,000 shares of
        preferred stock, none of which is issued and outstanding. The
        outstanding share of capital stock of Newco is duly authorized, validly
        issued, fully paid and nonassessable and not subject to preemptive
        rights. Upon consummation of the Merger and the Vista Exchange, the
        shares of Newco Common Stock to be issued pursuant to the Merger and the
        Vista Exchange will be duly authorized, and upon their issuance in
        accordance with the terms of this Agreement, validly issued, fully paid
        and nonassessable, and will not have been issued in violation of any
        preemptive rights. Newco does not, and at the Effective Time, except as
        expressly contemplated by this Agreement, Newco will not, have
        outstanding any options, warrants, calls, rights (including preemptive
        rights), commitments or agreements to which Newco or any Subsidiary of
        Newco will be a party or by which it will be bound in any case
        obligating Newco or any Subsidiary of Newco to issue, deliver, sell,
        purchase, redeem, or acquire, or cause to be issued, delivered, sold,
        purchased, redeemed, or acquired, additional shares of capital stock or
        any Voting Debt or other voting securities of Newco or any Subsidiary of
        Newco, or obligating Newco or any Subsidiary of Newco to grant, extend,
        or enter into any such option, warrant, call, right, commitment, or
        agreement.
 
             (ii) The authorized capital stock of Merger Sub consists of 1,000
        shares of common stock, $0.01 par value, all of which are issued and
        outstanding and owned of record and beneficially by Newco. The
        outstanding share of capital stock of Merger Sub is duly authorized,
        validly issued, fully paid and nonassessable and not subject to
        preemptive rights. Merger Sub does not, and at the Effective Time,
        except as contemplated by this Agreement, will not, have outstanding any
        options, warrants, calls, rights (including preemptive rights),
        commitments or agreements to which Merger Sub will be a party or by
        which it will be bound in any case obligating Merger Sub to issue,
        deliver, sell, purchase, redeem or acquire, or cause to be issued,
        delivered, sold, purchased, redeemed or acquired, additional shares of
        capital stock or any Voting Debt or other voting securities of Merger


                                      A-49
<PAGE>
 
        Sub, or obligating Merger Sub to grant, extend, or enter into any such
        option, warrant, call, right, commitment, or agreement.
 
          (c) AUTHORITY; NO VIOLATIONS; CONSENTS AND APPROVALS. Each of Newco
     and Merger Sub has all requisite corporate power and authority to enter
     into this Agreement and to consummate the transactions contemplated by this
     Agreement. The execution and delivery of this Agreement by Newco and Merger
     Sub, and the consummation by each of them of the transactions contemplated
     by this Agreement, have been duly authorized by all necessary corporate
     action on the part of each of them, including all necessary shareholder
     approval. This Agreement has been duly executed and delivered by each of
     Newco and Merger Sub, and, assuming this Agreement constitutes the valid
     and binding obligation of Vista and Midland, constitutes a valid and
     binding obligation of each of Newco and Merger Sub enforceable against each
     of them in accordance with its terms, subject, as to enforceability, to
     bankruptcy, insolvency, reorganization, moratorium and other laws of
     general applicability relating to or affecting creditors' rights and to
     general principles of equity (regardless of whether such enforceability is
     considered in a proceeding in equity or at law). The execution and delivery
     of this Agreement do not, and the consummation of the transactions
     contemplated hereby and compliance with the provisions hereof will not,
     conflict with, or result in any violation of, or default (with or without
     notice or lapse of time, or both) under, or give rise to a right of
     termination, cancellation or acceleration of any material obligation or to
     the loss of a material benefit under, or give rise to a right of purchase
     under, result in the creation of any Lien upon any of the properties or
     assets of Newco or Merger Sub under, or otherwise result in a material
     detriment to Newco or Merger Sub under, any provision of the Certificate of
     Incorporation or Bylaws of Newco or Merger Sub. No consent, approval, order
     or authorization of, or registration, declaration or filing with, or permit
     from any Governmental Entity is required by or with respect to Newco or
     Merger Sub in connection with the execution and delivery of this Agreement
     by, or the consummation of the transactions contemplated in this Agreement
     by, Newco or Merger Sub, except for: (i) the filing by Newco of the S-4
     with the SEC with respect to the offer and sale of Newco Common Stock
     pursuant to the Midland Merger; (ii) the filing by Newco of a Form D Notice
     of Sale of Securities Pursuant to Regulation D with the SEC, with respect
     to the offer and sale of Newco Common Stock pursuant to the Vista Exchange,
     and such other compliance with the Securities Act and the rules and
     regulations thereunder, as may be required in connection with this
     Agreement and the transactions contemplated hereby; (iii) the filing by
     Merger Sub of the Midland Articles of Merger with the Texas Secretary of
     State; (iv) the filing by Newco of the Vista Certificate of Merger with the
     Delaware Secretary of State and the Vista Articles of Merger with the Texas
     Secretary of State; (v) filings with, and approval of, the AMEX or Nasdaq;
     and (vi) such filings and approvals as may be required by any applicable
     state securities, "blue sky" or takeover laws, or environmental laws.
 
          (d) NO PRIOR ACTIVITIES. Except for this Agreement and the agreements
     and transactions contemplated herein, neither Newco nor Merger (i) Sub has
     entered into any agreements or arrangements with any person or (ii) is
     subject to or bound by any obligation or undertaking. Except as
     contemplated by this Agreement and the agreements and transactions
     contemplated herein, neither Newco nor Merger Sub has engaged, directly or
     indirectly, in any business activities of any type or kind.
 
                                   ARTICLE 4
 
                                   COVENANTS
 
     4.1 CONDUCT OF BUSINESS BY VISTA AND MIDLAND PENDING CLOSING. Prior to the
Effective Time, (a) Midland agrees as to itself and its Subsidiaries that
(except as expressly contemplated or permitted by this Agreement, or to the
extent that Vista shall otherwise consent in writing) and (b)Vista agrees as to
itself and Vista Sub that (except as expressly contemplated or permitted by this
Agreement, or to the extent that Midland shall otherwise consent in writing)
(for purposes of this Section 4.1 Midland and Vista each being a "Party"):
 
          (i) A Party and its Subsidiaries shall carry on its businesses in the
     usual, regular and ordinary course in substantially the same manner as
     heretofore conducted and shall use all commercially


                                      A-50
<PAGE>
 
     reasonable efforts to preserve intact its present business organizations,
     keep available the services of its current officers and employees and
     endeavor to preserve its relationships with customers, suppliers and others
     having business dealings with it to the end that its goodwill and ongoing
     business shall not be impaired in any material respect at the Effective
     Time;
 
          (ii) A Party shall not, and it shall not permit its Subsidiaries to,
     engage in any line of business in which it is not engaged as of the date
     hereof;
 
          (iii) A Party shall not, and it shall not permit its Subsidiaries to,
     (A) amend its certificate or articles of incorporation or by-laws or other
     organizational documents, (B)'split, combine, or reclassify any of its
     outstanding capital stock, partnership interests, or other securities,
     (C)'declare, set aside, or pay any dividends or other distributions
     (whether payable in cash, property, or securities) with respect to its
     capital stock, (D) issue, sell, or agree to issue or sell any securities,
     including its capital stock or other equity securities, any rights,
     options, or warrants to acquire its equity securities, or securities
     convertible into or exchangeable or exercisable for its equity securities
     (other than shares of Midland Common Stock issued pursuant to the exercise
     of any Midland Stock Option or any Midland Stock Warrant outstanding as of
     the date hereof), (E) purchase, cancel, retire, redeem, or otherwise
     acquire any of its outstanding equity securities or other securities, (F)
     merge or consolidate with, or transfer all or substantially all of its
     assets to, another corporation or other business entity, (G) liquidate,
     wind-up, or dissolve (or suffer any liquidation or dissolution), or (H)
     enter into any contract, agreement, commitment, or arrangement with respect
     to any of the foregoing;
 
          (iv) A Party shall not, and it shall not permit its Subsidiaries to,
     (A) acquire any corporation, partnership, or other business entity or any
     interest therein (other than interests in joint ventures, joint operation
     or ownership arrangements, or tax partnerships acquired in the ordinary
     course of business), (B) sell, lease or sublease, transfer, or otherwise
     dispose of or mortgage, pledge, or otherwise encumber any Oil and Gas
     Interests that, individually or in the aggregate, had a value at the time
     of such sale, lease, sublease, transfer, or disposition of $50,000 or more
     or any other assets that, individually or in the aggregate, have a value at
     the time of such sale, lease, sublease, transfer, or disposition of $50,000
     or more (except that this clause shall not apply to the sale of
     Hydrocarbons in the ordinary course of business) (C) farm-out any Oil and
     Gas Interest of Midland or Vista, as applicable, or interest therein, (D)
     sell, transfer, or otherwise dispose of or mortgage, pledge, or otherwise
     encumber any securities of any other Person, (E) make any material loans,
     advances, or capital contributions to, or investments in, any Person (other
     than loans or advances in the ordinary course of business and consistent
     with past practices, (F) enter into any material agreement not terminable
     by such Party upon notice of 30 days or less and without penalty or other
     obligation (other than Hydrocarbon Agreements entered into in the ordinary
     course of business and consistent with past practices), (G) enter into any
     material transaction not in the ordinary course of business and not
     contemplated by this Agreement, (H) agree with any Person to limit or
     otherwise restrict in any manner the ability of such Party or any of its
     Subsidiaries to compete or otherwise conduct its business, or (I) enter
     into any contract, agreement, commitment, or arrangement with respect to
     any of the foregoing;
 
          (v) A Party shall not, and it shall not permit its Subsidiaries to,
     (A) incur any indebtedness for borrowed money or any other obligation or
     liability (other than current liabilities incurred in the ordinary course
     of business and consistent with past practices) in excess of its then
     current borrowing capacity under its existing senior bank facilities, (B)
     assume, endorse (other than endorsements of negotiable instruments in the
     ordinary course of business), guarantee, or otherwise become liable or
     responsible (whether directly, contingently, or otherwise) for the
     liabilities or obligations of any Person, or (C) enter into any contract,
     agreement, commitment, or arrangement with respect to any of the foregoing;
 
          (vi) A Party shall, and shall cause its Subsidiaries to, operate,
     maintain, and otherwise deal with the Oil and Gas Interests of such Party
     in accordance with good and prudent oil and gas field practices (including
     the making of all appropriate repairs, renewals, and replacements thereof)
     and in accordance with all applicable oil and gas leases and other
     contracts or agreements and all applicable laws, rules, and regulations;


                                      A-51
<PAGE>
 
          (vii) A Party shall not, and it shall not permit its Subsidiaries to,
     pay, agree to pay, or incur drilling or other capital expenditures with
     respect to oil and gas wells in excess of ten percent (10%) of its current
     drilling and capital expenditure budget as respectively set forth on
     Schedules 3.1(bb) and 3.2(bb) in the aggregate (in either case, other than
     expenditures necessary for the preservation or protection of the public
     safety or health under emergency circumstances);
 
          (viii) A Party shall not, and it shall not permit its Subsidiaries to,
     resign, or transfer or otherwise voluntarily relinquish any right it has as
     of the date of this Agreement, as operator of any Oil and Gas Interest;
 
          (ix) A Party shall not, and it shall not permit its Subsidiaries
     to,(A) enter into, or otherwise become liable or obligated under or
     pursuant to, (x) any employee benefit, pension, or other plan (whether or
     nor subject to ERISA), (y) any other stock option, stock purchase,
     incentive, or deferred compensation plans or arrangements or other fringe
     benefit plan, or (z) any consulting, employment, severance, termination, or
     similar agreement with any Person, or amend or extend any such plan,
     arrangement, or agreement, (B) hire any key employee, except for payments
     made pursuant to any plan, agreement, or arrangement disclosed on Schedule
     3.1(l) of the Midland Disclosure Schedule or Schedule 3.2(l) of the Vista
     Disclosure Schedule, as applicable, grant, or otherwise become liable for
     or obligated to pay, any severance or termination payments, bonuses, or
     increases in compensation or benefits (other than payments, bonuses, or
     increases that are mandated by the terms of written agreements existing as
     of the date hereof or that are paid in the ordinary course of business,
     consistent with past practices, and not individually or in the aggregate
     material in amount) to, or forgive any indebtedness of, any employee or
     consultant, or (C) enter into any contract, agreement, commitment, or
     arrangement to do any of the foregoing;
 
          (x) A Party shall, and shall cause its Subsidiaries to, keep and
     maintain accurate books, records, and accounts in accordance with GAAP;
 
          (xi) A Party shall not, and it shall not permit its Subsidiaries to,
     create, incur, assume, or permit to exist any Lien on any of its assets,
     except for Permitted Encumbrances;
 
          (xii) A Party shall, and it shall permit its Subsidiaries to, (A) pay
     all Taxes, assessments, and other governmental charges imposed upon any of
     its assets or with respect to its franchises, business, income, or assets
     before any penalty or interest accrues thereon, (B) pay all claims
     (including claims for labor, services, materials, and supplies) that have
     become due and payable and which by law have or may become a Lien upon any
     of its assets prior to the time when any penalty or fine shall be incurred
     with respect thereto or any such Lien shall be imposed thereon, and (C)
     comply in all material respects with the requirements of all applicable
     laws, rules, regulations, and orders of any Governmental Entity, obtain or
     take all Governmental Actions necessary in the operation of its business,
     and comply with and enforce the provisions of all Midland Material
     Agreements or Vista Material Agreements, as applicable, including paying
     when due all rentals, royalties, expenses, and other liabilities relating
     to its business or assets (provided, however, that such Party or any of its
     Subsidiaries may contest the imposition of any such Taxes, assessments, and
     other governmental charges, any such claim, or the requirements of any
     applicable law, rule, regulation, or order or any Midland Material
     Agreement or Vista Material Agreement, as applicable, if done so in good
     faith by appropriate proceedings, if adequate reserves are established in
     accordance with GAAP or as may be determined as sufficient by Midland's
     board of directors or the General Partner of Vista, as applicable, and if
     such contest does not involve a risk of a Material Adverse Effect on
     Midland or Vista, as applicable);
 
          (xiii) A Party shall, and it shall permit its Subsidiaries to,
     maintain in full force and effect the policies or binders of insurance
     described in Section 3.1(p) or Section'3.2(p), as applicable, and
     applicable to it;
 
          (xiv) A Party shall not, and it shall not permit its Subsidiaries to,
     directly or indirectly, enter into or permit to exist any transaction
     (including the purchase, sale, lease, or exchange of any assets, unless
     otherwise permitted hereby, or the rendering of any service) with any
     Affiliate of such Party (other than

                                      A-52
<PAGE>
 
     any of its Subsidiaries) on terms that are less favorable to such Party or
     any of its Subsidiaries, as the case may be, than those that could be
     obtained at the time from unaffiliated third parties;
 
          (xv) A Party shall not, and it shall not permit its Subsidiaries to,
     enter into, or otherwise be a party to, any, shareholder agreement, voting
     trust, or other agreement or understanding relating to the voting of any
     shares of the capital stock or other securities of such Party or any of its
     Subsidiaries (other than the Midland Voting Agreement); and
 
          (xvi) A Party shall, and it shall permit its Subsidiaries to, at all
     times preserve and keep in full force and effect its corporate existence
     and rights and franchises material to its performance under this Agreement.
 
     4.2 ACCESS TO ASSETS, PERSONNEL, AND INFORMATION. From the date hereof
until the Effective Time, Midland agrees as to itself and its Subsidiaries that,
and Vista agrees as to itself and its Subsidiaries that (for purposes of this
Section 4.2, Midland and Vista each being a "Requesting Party" or the "Providing
Party," as applicable):
 
          (a) A Providing Party shall afford to the Requesting Party and the
     Requesting Party's Representatives, at the Requesting Party's sole risk and
     expense, reasonable access to any of the assets, books and records
     (including files, Tax Returns, and accountants' workpapers), contracts,
     employees, representatives, and agents (including attorneys, accountants,
     and independent engineers) and facilities (including office facilities) of
     such Providing Party and its Subsidiaries, and shall upon request furnish
     promptly to the Requesting Party (at the Requesting Party's expense) a copy
     of any file, book or record, contract, or other written information
     concerning such Providing Party and its Subsidiaries (or any of their
     respective assets) that is within the possession or control of the
     Providing Party; provided, however, that a Providing Party shall not be
     obligated to provide access to or to furnish to a Requesting Party any
     information that the Providing Party is contractually obligated not to so
     disclose under a written confidentiality agreement; provided, further, that
     the Providing Party notifies the Requesting Party of such confidentiality
     agreement. If requested by the Requesting Party, however, the Providing
     Party shall use reasonable efforts to obtain the required consent to
     provide such information. During such period, the Providing Party will make
     available to a reasonable number of the Requesting Party's Representatives
     adequate office space and facilities at the principal office facility of
     such Providing Party and will permit a reasonable number of the Requesting
     Party's Representatives to observe, but not participate in, staff meetings
     at those facilities and other facilities of the Providing Party and its
     Subsidiaries.
 
          (b) As soon as practicable following a Requesting Party's request
     therefor, the Providing Party shall provide the Requesting Party with
     descriptions of all material assets (including such Providing Party's Oil
     and Gas Interests) sufficient to permit such Requesting Party to properly
     identify and evaluate such assets. Such descriptions shall include, with
     respect to the Providing Party's Oil and Gas Interests, an electronic (A)
     listing of all properties by name, well, and internal accounting and land
     number designation and (B) division of interest for all wells and
     properties by field or location and by well by field or location,
     identifiable by reference to the listing described in clause (i) above.
 
          (c) A Requesting Party and the Requesting Party's Representatives
     shall have the right to make an environmental and physical assessment of
     the assets of the Providing Party and its Subsidiaries and, in connection
     therewith, shall have the right to enter and inspect such assets and all
     buildings and improvements thereon, conduct soil and water tests and
     borings, and generally conduct such tests, examinations, investigations,
     and studies as such Requesting Party deems necessary, desirable, or
     appropriate for the preparation of engineering or other reports relating to
     such assets, their condition, and the presence of Hazardous Materials. The
     Providing Party shall be provided 24 hours' prior notice of the activities,
     and the Providing Party's Representatives shall have the right to witness
     all such tests and investigations. The Requesting Party shall (and shall
     cause the Requesting Party's Representatives to) keep any data or
     information acquired by any such examinations and the results of any
     analyses of such data and information strictly confidential and will not
     (and will cause the Requesting Party's Representative not to) disclose any
     of such data, information, or results to any Person unless otherwise
     required by

                                      A-53
<PAGE>
 
     law or regulation and then only after written notice to the Providing Party
     of the determination of the need for disclosure. The Requesting Party
     hereby indemnifies and holds the Providing Party and its Subsidiaries, and
     the Providing Party's Representatives harmless from and against any and all
     claims arising out of or as a result of the activities of the Requesting
     Party and the Requesting Party's Representatives on the assets of the
     Providing Party and its Subsidiaries in connection with conducting such
     environmental and physical assessment, except to the extent of and limited
     by the gross negligence or willful misconduct of the Providing Party and
     its Subsidiaries, or any of the Providing Party's Representatives or any
     failure of any of them to warn the Requesting Party and the Requesting
     Party's Representatives of known hazardous or dangerous conditions.
 
          (d) A Providing Party will fully and accurately disclose, and will
     cause each of its Subsidiaries to fully and accurately disclose, to the
     Requesting Party and the Requesting Party's Representatives all information
     that is (A) requested by the Requesting Party or any of the Requesting
     Party's Representatives, (B) known (now or hereafter) to the Providing
     Party or any of its Subsidiaries, and (C) relevant in any manner or degree
     to the value, ownership, use, operation, development, or transferability of
     the assets of the Providing Party or any of its Subsidiaries.
 
          (e) A Providing Party shall furnish to the Requesting Party, promptly
     upon receipt or filing (as the case may be), a copy of each communication
     between the Providing Party and the SEC after the date hereof and each
     report, schedule, registration statement, or other document filed by such
     party with the SEC after the date hereof.
 
          (f) A Providing Party will (and will cause its Subsidiaries and
     Representatives to) fully cooperate in all respects with the Requesting
     Party and the Requesting Party's Representatives in connection with the
     Requesting Party's examinations, evaluations, and investigations described
     in this Section, and the Providing Party will (and will cause the Providing
     Party's Representatives to) fully cooperate in all respects with the
     Requesting Party and the Requesting Party's Representatives in connection
     with the Requesting Party's examinations, evaluations, and investigations
     described in this Section.
 
          (g) A Requesting Party agrees that it will not (and will cause the
     Requesting Party's Representatives not to) use any information obtained
     pursuant to this Section for any purpose unrelated to the consummation of
     the transactions contemplated by this Agreement.
 
          (h)(i) A Requesting Party shall not, and shall not permit its
     Affiliates, officers, employees, directors, shareholders or representatives
     to, disclose to any third party (other than such parties' respective legal
     counsel, accountants and other advisors, all of whom shall be required to
     observe the provisions of this Section 4.2(h)) any information received
     from the Providing Party in the course of investigating, negotiating, and
     performing the transactions contemplated by this Agreement; provided,
     however, that this provision shall not be applicable to information which:
     (1) becomes generally available to the public other than as a result of a
     disclosure by the Requesting Party or such Requesting Party's Affiliates,
     officers, directors, employees, shareholders or representatives, (2) was
     available to the Requesting Party on a non-confidential basis prior to its
     disclosure to the Requesting Party by the Providing Party or its
     Affiliates, officers, directors, employees, shareholders or
     representatives, (3) becomes available to the Requesting Party on a
     non-confidential basis from a source other than the Providing Party or its
     Affiliates, officers, directors, employees, shareholders or representatives
     when such source is entitled, to the best of the Requesting Party's
     knowledge, to make the disclosure, or (4) was independently developed by
     the Requesting Party without reference to the information received from the
     Providing Party. If either party or any of their respective Affiliates,
     officers, directors, employees, shareholders or representatives is
     requested or required to disclose any information received by it or to
     disclose any such information which is required to be kept confidential by
     this Section 4.2(h), such party agrees to provide the Providing Party with
     prompt notice of each such request, to the extent practicable, so that the
     Providing Party may seek an appropriate protective order or waive
     compliance by the Requesting Party with the provisions of this Section
     4.2(h) or both. If, absent the entry of a protective order or the receipt
     of a waiver under this Agreement, the Requesting Party, its Affiliates,
     officers, directors, employees, shareholders or representatives are, in the
     opinion of its counsel, legally compelled


                                      A-54
<PAGE>
 
     to disclose such information, the Requesting Party may disclose such
     information to the persons and to the extent required without liability
     under this Agreement, and such party agrees to exercise its reasonable
     commercial efforts to obtain reasonable assurances that confidential
     treatment will be accorded any such information so furnished.
 
          (ii) Midland and its Subsidiaries have taken, and after the date
     hereof Midland will, and Midland will cause its Subsidiaries to, take all
     steps reasonably necessary to safeguard and maintain the secrecy and
     confidentiality of any of Midland's assets that constitute confidential or
     proprietary information of Midland or its Subsidiaries. From and after the
     date hereof, Midland shall not, and Midland shall cause its Subsidiaries to
     not, disclose to any Person (other than Vista and such authorized
     representatives of Vista as Vista shall identify to Midland in writing) any
     confidential or proprietary information with respect to the business of
     Midland except (i) as otherwise required by law, or (ii) prior to the
     Closing Date, in the ordinary course and consistent with the past business
     practices of Midland and its Subsidiaries;
 
    provided, however, that the provisions of this Section 4.2(h) shall not
    prohibit Midland or Vista from including such confidential or proprietary
    information in the S-4 or any private placement memorandum distributed in
    connection with the Exchange Agreements.
 
          (i) Notwithstanding anything in this Section to the contrary, (A)
     Midland shall not be obligated under the terms of this Section to disclose
     to Vista or Vista's Representatives, or grant Vista or the Vista's
     Representatives access to, information that is within Midland's possession
     or control but subject to a valid and binding confidentiality agreement
     with a third party without first obtaining the consent of such third party,
     and Midland, to the extent reasonably requested by Vista, will use its
     reasonable best efforts to obtain any such consent; and (B) Vista shall not
     be obligated under the terms of this Section to disclose to Midland or
     Midland's Representatives, or grant Midland or Midland's Representatives
     access to, information that is within Vista's possession or control but
     subject to a valid and binding confidentiality agreement with a third party
     without first obtaining the consent of such third party, and Vista, to the
     extent reasonably requested by Midland, will use its reasonable best
     efforts to obtain any such consent.
 
     4.3 NO SOLICITATION BY MIDLAND.
 
          (a) From and after the date hereof, Midland will not, and will not
     authorize or permit any of its Representatives to, directly or indirectly,
     solicit or encourage (including by way of providing information) any
     prospective acquiror or the invitation or submission of any inquiries,
     proposals or offers or any other efforts or attempts that constitute, or
     may reasonably be expected to lead to, any Midland Acquisition Proposal (as
     hereinafter defined) from any person or engage in any discussions or
     negotiations with respect thereto or otherwise cooperate with or assist or
     participate in, or facilitate any such proposal; provided, however, that,
     notwithstanding any other provision of this Agreement, Midland's Board of
     Directors may take and disclose to the shareholders of Midland a position
     contemplated by Rule 14e-2(a) promulgated under the Exchange Act. Midland
     shall immediately cease and cause to be terminated any existing
     solicitation, initiation, encouragement, activity, discussion or
     negotiation with any parties conducted heretofore by Midland or any of its
     Representatives with respect to any Midland Acquisition Proposal existing
     on the date hereof. Midland will promptly notify in writing Vista of any
     receipt by Midland or any of its Subsidiaries of a request from a third
     party for information concerning Midland (or any of its Subsidiaries) and
     its business, properties and assets or the receipt of any Midland
     Acquisition Proposal, including the identity of the person or group
     requesting such information or making such Midland Acquisition Proposal,
     and the material terms and conditions of any Midland Acquisition Proposal.
 
          (b) As used in this Agreement, "Midland Acquisition Proposal" means
     any proposal or offer, other than a proposal or offer by Vista or any of
     its Affiliates, for, or that could be reasonably expected to lead to, a
     tender or exchange offer, a merger, consolidation or other business
     combination involving Midland or any of its Subsidiaries or any proposal to
     acquire in any manner a substantial equity interest in, or any substantial
     portion of the assets of, Midland or any of its Subsidiaries.


                                      A-55
<PAGE>

     4.4 NO SOLICITATION BY VISTA.
 
          (a) From and after the date hereof, Vista will not, and will not
     authorize or permit any of its Representatives to, directly or indirectly,
     solicit or encourage (including by way of providing information) any
     prospective acquiror or the invitation or submission of any inquiries,
     proposals or offers or any other efforts or attempts that constitute, or
     may reasonably be expected to lead to, any Vista Acquisition Proposal (as
     hereinafter defined) from any person or engage in any discussions or
     negotiations with respect thereto or otherwise cooperate with or assist or
     participate in, or facilitate any such proposal; provided, however, that,
     notwithstanding any other provision of this Agreement, the General Partner
     may take and disclose to the limited partners of Vista a position
     contemplated by Rule 14e-2(a) promulgated under the Exchange Act. Vista
     shall immediately cease and cause to be terminated any existing
     solicitation, initiation, encouragement, activity, discussion or
     negotiation with any parties conducted heretofore by Vista or any of its
     Representatives with respect to any Vista Acquisition Proposal existing on
     the date hereof. Vista will promptly notify in writing Midland of any
     receipt by Vista or Vista Sub of a request from a third party for
     information concerning Vista or Vista Sub and its business, properties and
     assets or the receipt of any Vista Acquisition Proposal, including the
     identity of the person or group requesting such information or making such
     Vista Acquisition Proposal, and the material terms and conditions of any
     Vista Acquisition Proposal.
 
          (b) As used in this Agreement, "Vista Acquisition Proposal" means any
     proposal or offer, other than a proposal or offer by Midland or any of its
     Affiliates, for, or that could be reasonably expected to lead to, a tender
     or exchange offer, a merger, consolidation or other business combination
     involving Vista or Vista Sub or any proposal to acquire in any manner a
     substantial equity interest in, or any substantial portion of the assets
     of, Vista or Vista Sub
 
     4.5 MIDLAND SHAREHOLDERS MEETING.
 
          (a) Midland shall call a meeting of its shareholders to be held as
     promptly as practicable after the date hereof for the purpose of voting
     upon this Agreement and the Midland Merger. Subject to the fiduciary duties
     of the Board of Directors of Midland, Midland will (through its Board of
     Directors) recommend to its shareholders approval of such matters and not
     rescind such recommendation and shall use its reasonable best efforts to
     obtain approval and adoption of this Agreement and the Midland Merger by
     its shareholders. Midland shall use all commercially reasonable efforts to
     hold such meeting as soon as practicable after the date upon which the S-4
     becomes effective.
 
          (b) Notwithstanding clause (a) above, however, the following shall be
     conditions (which shall be for the benefit of both Midland and Vista) to
     the recommendation of the Board of Directors of Midland to the Midland
     shareholders, the holding of the Midland Meeting and the mailing of the
     Proxy Statement:
 
             (i) The fairness opinion described in Section 3.1(hh) shall have
        been confirmed in writing and shall not have been withdrawn, revoked, or
        modified;
 
             (ii) Midland shall have received an opinion (reasonably acceptable
        to Midland and Vista) from Arthur Andersen LLP (or such other firm as is
        reasonably acceptable to Midland and Vista) to the effect that (A) the
        Midland Merger will be treated for federal income tax purposes as a
        reorganization within the meaning of Section 368(a) of the Code, (B)
        each of Newco, Midland, and Merger Sub will be a party to such
        reorganization within the meaning of Section 368(b) of the Code, (C) no
        gain or loss will be recognized by Newco, Midland, or Merger Sub as a
        result of the Midland Merger, and (D) no gain or loss will be recognized
        by a shareholder of Midland as a result of the Midland Merger with
        respect to the shares of Midland Common Stock converted solely into
        shares of Newco Common Stock, and such opinion shall not have been
        withdrawn, revoked, or modified;
 
             (iii) Vista shall have received from Grant Thornton LLP, Midland's
        independent auditors, a letter, dated a date within two business days
        before the date on which the Proxy Statement is first


                                      A-56
<PAGE>
 
        mailed to the shareholders of Midland, with respect to the financial
        statements of Midland and other financial information about Midland
        included (or incorporated by reference) in the Proxy Statement, such
        letter to be in substantially the form described in Section 5.2(c); and
 
             (iv) Midland shall have received from Arthur Andersen LLP, Vista's
        independent certified public accountants, a letter dated a date within
        two business days before the date on which the Proxy Statement is first
        mailed to the shareholders of Midland, with respect to the Financial
        Statements of Vista and other financial information about Vista included
        in the Proxy Statement, such letter to be in substantially the form
        described in Section 5.3(d).
 
     4.6 S-4 AND PROXY STATEMENT.
 
          (a) Vista, Newco, and Midland shall cooperate and promptly prepare the
     S-4, and Vista shall cause Newco to file the S-4 with the SEC as soon as
     practicable after the date hereof. Vista and Newco shall use their
     reasonable best efforts, and Midland shall cooperate fully with Vista and
     Newco (including furnishing all information concerning Midland and the
     holders of Midland Common Stock as may be reasonably requested by Vista and
     Newco), to have the S-4 declared effective under the Securities Act as
     promptly as practicable after such filing. Newco shall use its reasonable
     best efforts, and Midland shall cooperate fully with Newco, to obtain all
     necessary state securities laws or "blue sky" permits, approvals, and
     registrations in connection with the issuance of Newco Common Stock
     pursuant to the Midland Merger.
 
          (b) Vista, Newco, and Midland will cause the S-4 (including the Proxy
     Statement), at the time it becomes effective under the Securities Act, to
     comply as to form in all material respects with the applicable provisions
     of the Securities Act, the Exchange Act, and the rules and regulations of
     the SEC thereunder.
 
          (c) Midland hereby covenants and agrees with Vista and Newco that (i)
     the S-4 (at the time it becomes effective under the Securities Act and at
     the Effective Time) will not contain an untrue statement of a material fact
     or omit to state a material fact required to be stated therein or necessary
     to make the statements therein not misleading (provided, however, that this
     clause shall apply only to information contained in the S-4 that was
     supplied by Midland specifically for inclusion therein) and (ii) the Proxy
     Statement (at the time it is first mailed to shareholders of Midland, at
     the time of the Midland Meeting, and at the Effective Time) will not
     contain an untrue statement of a material fact or omit to state a material
     fact required to be stated therein or necessary in order to make the
     statements therein, in light of the circumstances under which they are
     made, not misleading provided, however, that this clause shall not apply to
     any information contained in the Proxy Statement that was supplied by Vista
     or Newco specifically for inclusion therein). If, at any time prior to the
     Effective Time, any event with respect to Midland, or with respect to other
     information supplied by Midland specifically for inclusion in the S-4,
     occurs and such event is required to be described in an amendment to the
     S-4, Midland shall promptly notify Vista and Newco of such occurrence and
     shall cooperate with Newco in the preparation and filing of such amendment.
     If, at any time prior to the Effective Time, any event with respect to
     Midland, or with respect to other information included in the Proxy
     Statement, occurs and such event is required to be described in a
     supplement to the Proxy Statement, such event shall be so described and
     such supplement shall be promptly prepared, filed, and disseminated.
 
          (d) Vista and Newco hereby covenant and agree with Midland that (i)
     the S-4 (at the time it becomes effective under the Securities Act and at
     the Effective Time) will not contain an untrue statement of a material fact
     or omit to state a material fact required to be stated therein or necessary
     to make the statements therein not misleading (provided, however, that this
     clause shall not apply to any information contained in the S-4 that was
     supplied by Midland specifically for inclusion therein) and (ii) the Proxy
     Statement (at the time it is first mailed to shareholders of Midland, at
     the time of the Midland Meeting, and at the Effective Time) will not
     contain an untrue statement of a material fact or omit to state a material
     fact required to be stated therein or necessary in order to make the
     statements therein, in light of the circumstances under which they are
     made, not misleading (provided, however, that this clause shall apply only
     to information contained in the Proxy Statement that was supplied by Vista
     or


                                      A-57
<PAGE>
 
     Newco specifically for inclusion therein). If, at any time prior to the
     Effective Time, any event with respect to Vista or Newco, or with respect
     to other information included in the S-4, occurs and such event is required
     to be described in an amendment to the S-4, such event shall be so
     described and such amendment shall be promptly prepared and filed. If at
     any time prior to the Effective Time, any event with respect to Vista or
     Newco, or with respect to other information supplied by Vista or Newco
     specifically for inclusion in the Proxy Statement, occurs and such event is
     required to be described in a supplement to the Proxy Statement, Vista or
     Newco shall promptly notify Midland of such occurrence and shall cooperate
     with Midland in the preparation, filing, and dissemination of such
     supplement.
 
          (e) No amendment or supplement to the S-4 or the Proxy Statement will
     be filed or disseminated to the shareholders of Midland without the
     approval of Vista, Newco, and Midland. Newco shall advise Vista and
     Midland, promptly after it receives notice thereof, of the time when the
     S-4 has become effective under the Securities Act, the issuance of any stop
     order with respect to the S-4, the suspension of the qualification of the
     Newco Common Stock issuable in connection with the Merger and the Vista
     Exchange, for offering or sale in any jurisdiction, or any comments or
     requests for additional information by the SEC.
 
     4.7 STOCK EXCHANGE LISTING. Newco shall use its reasonable best efforts to
cause the shares of Newco Common Stock to be issued in the Midland Merger and
the Vista Exchange and upon exercise of the Midland Stock Options, Midland
Warrants or Midland Common Stock Warrants to be approved for listing on the AMEX
or Nasdaq, subject to official notice of issuance prior to the Closing Date.
 
     4.8 ADDITIONAL ARRANGEMENTS. Subject to the terms and conditions herein
provided, each of Midland, Vista and Newco will take, or cause to be taken, all
action and will do, or cause to be done, all things necessary, appropriate, or
desirable under applicable laws and regulations or under applicable governing
agreements to consummate and make effective the transactions contemplated by
this Agreement, including using its reasonable best efforts to obtain all
necessary waivers, consents, and approvals and effecting all necessary
registrations and filings. Each of Midland, Vista, and Newco will take, or cause
to be taken, all action or will do, or cause to be done, all things necessary,
appropriate, or desirable to cause the covenants and conditions applicable to
the transactions contemplated hereby to be performed or satisfied as soon as
practicable. In addition, if any Governmental Entity shall have issued any
order, decree, ruling, or injunction or taken any other action that would have
the effect of restraining, enjoining, or otherwise prohibiting or preventing the
consummation of the transactions contemplated hereby, each of Midland, Vista,
and Newco will use its reasonable best efforts to have such order, decree,
ruling, or injunction or other action declared ineffective as soon as
practicable.
 
     4.9 AGREEMENTS OF RULE 145 AFFILIATES. At least 30 days prior to the
Effective Time, Vista shall cause to be prepared and delivered to Midland, and
Midland shall cause to be prepared and delivered to Vista, a list identifying
all persons who, at the time of the Midland Meeting or the Vista Exchange, as
applicable, may be deemed to be "affiliates" of Midland or Vista, as that term
is used in paragraphs (c) and (d) of Rule 145 under the Securities Act (the
"Rule 145 Affiliates"). Vista shall use its reasonable best efforts to cause
each person who is identified as a Rule 145 Affiliate in such Vista list to
deliver to Vista and Newco, at or prior to the Effective Time, a written
agreement, in the form attached as Exhibit 4.9 hereto (the "Affiliate
Agreement"). Vista and the Rule 145 Affiliates shall be relieved of this
obligation under the foregoing provisions of this Section 4.9 and such written
agreements if, and to the extent, such Rule 145 is amended not to require such
written agreements or any of the covenants contained therein. Midland shall use
its reasonable best efforts to cause each person who is identified as a Rule 145
Affiliate in such Midland list to deliver to Midland and Newco, at or prior to
the Effective Time, an Affiliate Agreement. Midland and the Rule 145 Affiliates
shall be relieved of this obligation under the foregoing provisions of this
Section 4.9 and such written agreements if, and to the extent, such Rule 145 is
amended not to require such written agreements or any of the covenants contained
therein.
 
     4.10 PUBLIC ANNOUNCEMENTS. Prior to the Closing, the parties hereto will
consult with each other before issuing any press release or otherwise making any
public statements with respect to the transactions contemplated by this
Agreement and shall not issue any press release or make any such public
statement prior


                                      A-58
<PAGE>
 
to obtaining the approval of the other parties hereto; provided, however, that
such consent shall not be required where such release or announcement is
required by applicable law or stock exchange rule; and provided further,
however, that any of the parties hereto may respond to inquiries by the press or
others regarding the transactions contemplated by this Agreement, so long as
such responses are consistent with such party's previously issued press
releases.
 
     4.11 NOTIFICATION OF CERTAIN MATTERS. Midland shall give prompt notice to
Vista of (a) any representation or warranty contained in Section 3.1 being
untrue or inaccurate when made, (b) the occurrence of any event or development
that would cause (or could reasonably be expected to cause) any representation
or warranty contained in Section 3.1 to be untrue or inaccurate on the Closing
Date, or (c) any failure of Midland to comply with or satisfy any covenant,
condition, or agreement to be complied with or satisfied by it hereunder. Vista
shall give prompt notice to Midland of (i) any representation or warranty
contained in Section 3.2 or 3.3 being untrue or inaccurate when made, (ii) the
occurrence of any event or development that would cause (or could reasonably be
expected to cause) any representation or warranty contained in Section 3.2 or to
be untrue or inaccurate on the Closing Date, or (iii) any failure of Vista,
Newco, or Merger Sub to comply with or satisfy any covenant, condition, or
agreement to be complied with or satisfied by it hereunder.
 
     4.12 PAYMENT OF EXPENSES. Each party hereto shall pay its own fees and
expenses (including fees and expenses of such parties' attorneys and
accountants) incident to preparing for, entering into, and carrying out this
Agreement and the consummation of the transactions contemplated hereby, whether
or not the Merger and the Vista Exchange shall be consummated, except that (a)
the fees and expenses (including fees and expenses of such parties' attorneys
and accountants) incurred by a party terminating this Agreement as provided
below in connection with this Agreement and the transactions contemplated herein
(including fees and expenses incurred in connection with the preparation and
filing of the S-4 with the SEC and the fees and expenses incurred in connection
with the printing, mailing and distribution of the Proxy Statement) shall be
reimbursed, borne and paid (i) if this Agreement is terminated by Midland
pursuant to Section 6.1(d), by Vista up to $300,000, and (ii) if this Agreement
is terminated by Vista pursuant to Section 6.1(c), by Midland up to $300,000 and
(b) if the Merger and the Vista Exchange are consummated all fees and expenses
(including fees and expenses of such parties' attorneys and accountants)
incident to preparing for, entering into and carrying out this Agreement and the
consummation of the transactions contemplated hereby shall be borne and paid by
Newco. The provisions for reimbursement of fees and expenses in this Section
shall be in addition to and not a limitation upon the liabilities or obligations
of a party as a result of a termination pursuant to Section 6.1(c) or 6.1(d).
 
     4.13 INDEMNIFICATION.
 
          (a) From and after the Effective Time, the MM Surviving Corporation
     shall indemnify and hold harmless each person and shall advance expenses
     incurred by each person who is, has been at any time prior to the date
     hereof, or becomes prior to the Effective Time an officer or director of
     Midland or any of its Subsidiaries (collectively, the "Midland Indemnified
     Parties") against all losses, claims, damages, liabilities, costs or
     expenses (including attorney's fees), judgments, and amounts paid in
     settlement in connection with any claim, action, suit, proceeding, or
     investigation arising out of or pertaining to acts or omissions, or alleged
     acts or omissions, by him in his capacity as an officer or director of
     Midland or any of its Subsidiaries, which acts or omissions occurred prior
     to the Effective Time, to the full extent permitted by applicable law and
     by the Bylaws of Midland in effect prior to the Effective Time, which
     Bylaws make mandatory the indemnification of and advancement of expenses to
     all Midland Indemnified Parties to the full extent permitted by Article
     2.02-1 of the TBCA. The procedures associated with such indemnification
     shall be the same as those associated with the Midland Indemnified Parties'
     indemnification from Midland or any of its respective Subsidiaries, as the
     case may be, immediately prior to the Effective Time (provided, however,
     that the determination that such indemnification is permissible under
     Section B of Article 2.02-1 of the TBCA shall be made by special legal
     counsel selected by the Board of Directors as set forth in Section F(3) of
     Article 2.02-1, such selection to be subject to the consent of a majority
     of the Midland Indemnified Parties in such instance, which consent may not
     be unreasonably withheld; and, further provided, however, that the MM
     Surviving Corporation shall be under no


                                      A-59
<PAGE>
 
     obligation to deposit trust funds pursuant to any "change-in-control" or
     similar provisions). Midland hereby agrees that, from and after the date
     hereof until the Effective Time, it will not (and it will cause each of its
     Subsidiaries not to) amend, modify, or otherwise alter any contractual
     provision under which any Midland Indemnified Party is entitled to
     indemnification from Midland or any of its Subsidiaries, as the case may
     be, at the time of the execution of this Agreement. The provisions of this
     Section are intended to be for the benefit of, and shall be enforceable by,
     the parties hereto and each Midland Indemnified Party and their respective
     heirs and representatives.
 
          (b) From and after the Effective Time, Vista shall indemnify and hold
     harmless each person or entity, and shall advance expenses incurred by each
     person or entity who is, has been at any time prior to the date hereof, or
     becomes prior to the Effective Time an officer, director or partner of the
     General Partner, Vista or any of its Subsidiaries (collectively, the "Vista
     Indemnified Parties") against all losses, claims, damages, liabilities,
     costs or expenses (including attorney's fees), judgments, and amounts paid
     in settlement in connection with any claim, action, suit, proceeding, or
     investigation arising out of or pertaining to acts or omissions, or alleged
     acts or omissions, by such Vista Indemnified Party in his or its capacity
     as an officer, director, or partner of the General Partner, Vista or any of
     its Subsidiaries, which acts or omissions occurred prior to the Effective
     Time to the full extent permitted by applicable law. The procedures
     associated with such indemnification shall be the same as those associated
     with the Vista Indemnified Parties' indemnification from Vista or any of
     its Subsidiaries, as the case may be, immediately prior to the Effective
     Time (provided, however, that Vista shall be under no obligation to deposit
     trust funds pursuant to any "change-in-control" or similar provisions).
     Vista hereby agrees that, from and after the date hereof until the
     Effective Time, it will not (and it will cause each of its Subsidiaries not
     to) amend, modify, or otherwise alter any contractual provision under which
     any Vista Indemnified Party is entitled to indemnification from Vista or
     any of its Subsidiaries at the time of the execution of this Agreement. The
     provisions of this Section are intended to be for the benefit of, and shall
     be enforceable by, the parties hereto and each Vista Indemnified Party and
     their respective heirs and representatives.
 
     4.14 INDEMNIFICATION AGREEMENTS. Contemporaneously with the Closing, Newco
shall enter into indemnification agreements, substantially in the form attached
hereto as Exhibit 4.14(a)(each an "Indemnification Agreement"), with each of its
officers and directors and with each of the officers and directors listed on
Schedule 4.14 of the Midland Disclosure Schedule, substantially in the form
attached hereto as Exhibit 4.14(b). The provisions of this Section are intended
to be for the benefit of, and shall be enforceable by, the parties hereto and
each of the Persons named in this Section and their respective heirs and
representatives.
 
     4.15 REGISTRATION OF SHARES TO BE ISSUED PURSUANT TO STOCK
OPTIONS. Promptly after the Effective Time, Newco shall file with the SEC a
registration statement on Form S-8, effective as of the Effective Time, with
respect to the shares of Newco Common Stock to be issued upon exercise of the
Midland Stock Options. Newco shall use all reasonable efforts to maintain the
effectiveness of such registration statement (and maintain the current status of
the related prospectus) for so long as any Midland Stock Options remain
outstanding. The provisions of this Section are intended to be for the benefit
of, and shall be enforceable by, the parties hereto and each holder of a Midland
Stock Option and their respective heirs and representatives.
 
     4.16 REGISTRATION RIGHTS AGREEMENT. (a) Contemporaneously with the Closing,
Newco shall enter into a Registration Rights Agreement, substantially in the
form attached hereto as Exhibit 4.16(a) (the "Vista Registration Rights
Agreement"), with each of the shareholders of the General Partner and each of
the limited partners of Vista immediately prior to the Vista Exchange.
 
     (b) Contemporaneously with the Closing, Newco shall enter into a
Registration Rights Agreement, substantially in the form attached hereto as
Exhibit 4.16(b) (the "Midland Registration Rights Agreement") with each holder
of a Midland Exchange Stock Option.
 
     (c) The provisions of this Section are intended to be for the benefit of,
and shall be enforceable by, the parties hereto and each of the Persons named or
described in this Section and their respective heirs and representatives.


                                      A-60
<PAGE>
 
     4.17 RESIGNATIONS OF OFFICERS AND DIRECTORS OF MIDLAND. Contemporaneously
with the execution and delivery of this Agreement, Midland shall obtain written
resignations from each of its officers and directors under which such persons
have resigned as an officer and/or director of Midland effective as of the
Effective Time. Contemporaneously with the execution and delivery of this
Agreement, Midland shall enter into a Termination Agreements, substantially in
the forms attached hereto as Exhibits 4.17(a) and 4.17(b) (each a "Termination
Agreement"), with Howard E. Ehler and Marilyn D. Wade, respectively.
 
     4.18 NEWCO LONG-TERM INCENTIVE PLAN. Prior to the Effective Time, but to
become effective immediately after the Effective Time, Newco shall approve and
adopt the Vista Energy Resources, Inc. 1998 Key Employee Stock Option Plan,
substantially in the form attached hereto as Exhibit 4.18 (the "Newco Long-Term
Incentive Plan").
 
     4.19 MIDLAND OPTION EXERCISE AGREEMENTS. Within 30 days from the date
hereof, Midland shall use its reasonable best efforts to cause each of the
holders of issued and outstanding Midland Stock Options (other than Midland
Exchange Stock Options) to execute an Option Exercise Agreement.
 
     4.20 TRANSACTIONS WITH AFFILIATES. For a period of one year following the
Effective Time, except for the grant of options pursuant to the terms of the
Newco Long-Term Incentive Plan and the issuance of shares of Newco Common Stock
underlying such options or the Newco Warrants, Newco shall not issue shares of
Newco Common Stock or securities exchangeable or exercisable for or convertible
into shares of Newco Common Stock to any person or entity that is an affiliate
of Newco for consideration that is less than fair market value of the securities
issued. For a transaction or series of related transactions involving value of
less than $1,000,000, the fair market value of the Newco Common Stock or other
security to be issued will be determined by the Board of Directors of Newco
after taking into consideration the historical trading price of Newco Common
Stock. For a transaction or series of related transactions involving value of
more than $1,000,000, the fair market value of the Newco Common Stock or other
security to be issued will be determined by the Board of Directors of Newco
after (i) taking into consideration the historical trading price of Newco Common
Stock and (ii) receipt of an opinion from a nationally recognized investment
banking firm that such transaction is fair, from a financial point of view, to
Newco.
 
                                   ARTICLE 5
 
                                   CONDITIONS
 
     5.1 CONDITIONS TO EACH PARTY'S OBLIGATION TO EFFECT THE MERGER AND THE
VISTA EXCHANGE. The respective obligations of each party to effect the Merger
and the Vista Exchange shall be subject to the satisfaction, at or prior to the
Closing Date, of the following conditions:
 
          (a) SHAREHOLDER APPROVAL. The Midland Merger and this Agreement shall
     have been duly and validly approved and adopted by the shareholders of
     Midland;
 
          (b) FAIRNESS OPINION. The fairness opinion described in Section
     3.1(hh) shall have been confirmed in writing and shall not have been
     withdrawn, revoked, or modified;
 
          (c) TAX OPINION. The tax opinion described in Section 4.5(b)(ii) shall
     not have been withdrawn, revoked, or modified;
 
          (d) EXCHANGE LISTING. The shares of Newco Common Stock issuable
     pursuant to the Midland Merger and the Vista Exchange and the shares of
     Newco Common Stock to be issued upon exercise of the Midland Stock Options
     and the Midland Warrants shall have been authorized for listing on the AMEX
     or Nasdaq, subject to official notice of issuance;
 
          (e) OTHER APPROVALS. All consents, approvals, permits, and
     authorizations required to be obtained prior to the Effective Time from,
     any Governmental Entity in connection with the execution and delivery of
     this Agreement and the consummation of the transactions contemplated hereby
     by Midland, Vista, Newco, and Merger Sub shall have been made or obtained
     (as the case may be), except where the failure to obtain such consents,
     approvals, permits, and authorizations would not be reasonably likely to
     result in


                                      A-61
<PAGE>
 
     a Material Adverse Effect on Newco (assuming the Midland Merger and the
     Vista Exchange have taken place) or to materially adversely affect the
     consummation of the Midland Merger and the Vista Exchange;
 
          (f) SECURITIES LAW MATTERS. The S-4 shall have become effective under
     the Securities Act and shall be effective at the Effective Time, and no
     stop order suspending such effectiveness shall have been issued, no action,
     suit, proceeding, or investigation by the SEC to suspend such effectiveness
     shall have been initiated and be continuing, and all necessary approvals
     under state securities laws relating to the issuance or trading of the
     Newco Common Stock to be issued in the Midland Merger and the Vista
     Exchange shall have been received; and
 
          (g) NO INJUNCTIONS OR RESTRAINTS. No temporary restraining order,
     preliminary or permanent injunction, or other order issued by any court of
     competent jurisdiction or other legal restraint or prohibition preventing
     the consummation of the Midland Merger and the Vista Exchange shall be in
     effect; provided, however, that prior to invoking this condition, each
     party shall have complied fully with its obligations under Section 4.8 and,
     in addition, shall use all reasonable efforts to have any such decree,
     ruling, injunction, or order vacated, except as otherwise contemplated by
     this Agreement.
 
     5.2 CONDITIONS OF OBLIGATIONS OF VISTA, NEWCO, AND MERGER SUB. The
obligations of Vista and Newco to effect the Vista Exchange are subject to the
satisfaction of the following conditions, any or all of which may be waived in
whole or in part by Vista.
 
          (a) REPRESENTATIONS AND WARRANTIES. Each of the representations and
     warranties of Midland set forth in Section 3.1 shall be true and correct in
     all material respects (provided that any representation or warranty of
     Midland contained herein that is qualified by a materiality standard or a
     Material Adverse Effect qualification shall not be further qualified
     hereby) as of the date of this Agreement and (except to the extent such
     representations and warranties speak as of an earlier date) as of the
     Closing Date as though made on and as of the Closing Date, and Vista shall
     have received a certificate signed on behalf of Midland by the chief
     executive officer and the chief financial officer of Midland to such
     effect;
 
          (b) PERFORMANCE OF COVENANTS AND AGREEMENTS. Midland shall have
     performed in all material respects all covenants and agreements required to
     be performed by it under this Agreement at or prior to the Closing Date,
     and Vista shall have received a certificate signed on behalf of Midland by
     the chief executive officer and the chief financial officer of Midland to
     such effect;
 
          (c) COMFORT LETTER. Vista shall have received a letter from Grant
     Thornton LLP, Midland's independent auditors, of the kind contemplated by
     the Statement of Auditing Standards with respect to Letters to Underwriters
     promulgated by the American Institute of Certified Public Accountants,
     dated as of a date within two business days prior to the Closing Date, in
     form and substance reasonably satisfactory to Vista, in connection with the
     procedures undertaken by them with respect to the financial statements of
     Midland and its consolidated Subsidiaries included (or incorporated by
     reference) in the S-4 and the other matters contemplated by such Statement
     of Auditing Standards and customarily included in similar letters relating
     to transactions similar to the Midland Merger;
 
          (d) DISSENTERS' RIGHTS. The aggregate number of shares of capital
     stock of Midland, which are entitled to vote at the Midland Meeting and are
     held of record by a Person or Persons who exercise their right, if any,
     under the TBCA to dissent from the proposed Midland Merger, shall not
     exceed five percent (5%) of the total number of issued and outstanding
     shares of capital stock of Midland held of record as of the record date for
     the Midland Meeting and entitled to vote on the proposed Midland Merger at
     such meeting.
 
          (e) LEGAL OPINION. At the Closing, Vista shall have received from Law
     Snakard & Gambill, Midland's legal counsel, an opinion dated the Closing
     Date in substantially the form set forth as Exhibit 5.2(e) hereto.
 
          (f) NO ADVERSE CHANGE. From the date of this Agreement through the
     Closing, there shall not have occurred any change in the condition
     (financial or otherwise), operations, or business of Midland


                                      A-62
<PAGE>
 
     and its Subsidiaries, taken as a whole, that would have or would be
     reasonably likely to have a Material Adverse Effect on Midland (other than
     changes, including changes in commodity prices, generally prevalent
     affecting the oil and gas industry).
 
          (g) MIDLAND OPTION EXERCISE AGREEMENTS. Midland shall have received an
     Option Exercise Agreement executed by each of the holders of issued and
     outstanding Midland Stock Options who is an executive officer or director
     of Midland.
 
     5.3 CONDITIONS OF OBLIGATIONS OF MIDLAND. The obligation of Midland to
effect the Midland Merger is subject to the satisfaction of the following
conditions, any or all of which may be waived in whole or in part by Midland:
 
          (a) REPRESENTATIONS AND WARRANTIES. Each of the representations and
     warranties of Vista, Newco, and Merger Sub set forth in Sections 3.2 and
     3.3 shall be true and correct in all material respects (provided that any
     representation or warranty of Vista, Newco, or Merger Sub contained herein
     that is qualified by a materiality standard or a Material Adverse Effect
     qualification shall not be further qualified hereby) as of the date of this
     Agreement and (except to the extent such representations and warranties
     speak as of an earlier date) as of the Closing Date as though made on and
     as of the Closing Date, and Midland shall have received a certificate
     signed on behalf of Vista by the General Partner to such effect;
 
          (b) PERFORMANCE OF COVENANTS AND AGREEMENTS. Vista, Newco, and Merger
     Sub shall have performed in all material respects all covenants and
     agreements required to be performed by them under this Agreement at or
     prior to the Closing Date, and Midland shall have received a certificate
     signed on behalf of Vista by the General Partner to such effect;
 
          (c) LEGAL OPINION. At the Closing, Midland shall have received from
     Vinson & Elkins L.L.P., Vista's legal counsel, an opinion dated the Closing
     Date in substantially the form set forth as Exhibit 5.3(c) hereto.
 
          (d) COMFORT LETTER. Midland shall have received a letter from Arthur
     Andersen LLP, Vista's independent certified public accountants, of the kind
     contemplated by the Statement of Auditing Standards with respect to Letters
     to Underwriters promulgated by the American Institute of Certified Public
     Accountants, dated as of a date within two business days prior to the
     Closing Date, in form and substance reasonably satisfactory to Midland, in
     connection with the procedures undertaken by them with respect to the
     financial statements of Vista and its consolidated Subsidiaries included in
     the S-4 and the other matters contemplated by such Statement of Auditing
     Standards and customarily included in similar letters relating to
     transactions similar to the Midland Merger; and
 
          (e) NO ADVERSE CHANGE. From the date of this Agreement through the
     Closing, there shall not have occurred any change in the condition
     (financial or otherwise), operations, or business of Vista and its
     Subsidiaries, taken as a whole, that would have or would be reasonably
     likely to have a Material Adverse Effect on Vista (other than changes,
     including changes in commodity prices, generally prevalent affecting the
     oil and gas industry).
 
          (f) EXCHANGE AGREEMENTS. Newco shall have received an Exchange
     Agreement from each holder of GP Common Stock and each holder of a
     Partnership Interest.


                                      A-63
<PAGE>
 
                                   ARTICLE 6
 
                                  TERMINATION
 
     6.1 TERMINATION RIGHTS. This Agreement may be terminated and the Merger may
be abandoned at any time prior to the Effective Time, whether before or after
approval of the Merger and this Agreement by the shareholders of Midland and the
partners of Vista:
 
          (a) By mutual written consent of Vista and Midland;
 
          (b) By either Midland or Vista if (i) the Merger have not been
     consummated by October 30, 1998 (provided, however, that the right to
     terminate this Agreement pursuant to this clause (i) shall not be available
     to any party whose breach of any representation or warranty or failure to
     perform any covenant or agreement under this Agreement has been the cause
     of or resulted in the failure of the Merger to occur on or before such
     date), (ii) any Governmental Entity shall have issued an order, decree, or
     ruling or taken any other action permanently restraining, enjoining, or
     otherwise prohibiting the Merger and such order, decree, ruling, or other
     action shall have become final and nonappealable (provided, however, that
     the right to terminate this Agreement pursuant to this clause (ii) shall
     not be available to any party until such party has used all reasonable
     efforts to remove such injunction, order, or decree), or (iii) any required
     approval of the shareholders or partners of a party, as applicable, shall
     not have been obtained by reason of the failure to obtain the required vote
     upon a vote held at a duly held meeting of shareholders of Midland, or at
     any adjournment thereof (provided, however, that Midland shall not have the
     right to terminate this Agreement pursuant to this clause (iii) if Vista
     then has the right to terminate this Agreement pursuant to subsection (e)
     of this Section);
 
          (c) By Vista if (i) there has been a breach of the representations and
     warranties made by Midland in Section 3.1 of this Agreement or (ii) Midland
     has failed to comply in any material respect with any of its covenants or
     agreements contained in this Agreement and such failure has not been, or
     cannot be, cured within a reasonable time after notice and demand for cure
     thereof which period in no event shall extend beyond October 30, 1998.
 
          (d) By Midland if (i) there has been a breach of the representations
     and warranties made by Vista, Newco, or Merger Sub in Sections 3.2 and 3.3
     of this Agreement, (ii) Vista, Newco, or Merger Sub has failed to comply in
     any material respect with any of its covenants or agreements contained in
     this Agreement, and, in either such case, such breach or failure has not
     been, or cannot be, cured within a reasonable time after notice and a
     demand for cure thereof which period in no event shall extend beyond
     October 30, 1998;
 
          (e) By Vista if (i) the Board of Directors of Midland shall have
     failed to recommend adoption of the Midland Merger and this Agreement at
     the time the Proxy Statement is first mailed to shareholders of Midland or
     shall have amended or withdrawn any such recommendation and such
     recommendation is not reinstated in its prior form within five business
     days after such amendment or withdrawal or (ii) (x) the shareholders of
     Midland fail to duly and validly adopt the Midland Merger and this
     Agreement at the Midland Meeting or any adjournment thereof or (y) the
     Midland Meeting does not occur for any reason (other than as a result of a
     breach of this Agreement by Vista) prior to October 29, 1998 (and if this
     Agreement is terminated pursuant to this subsection, Vista shall have the
     right to receive from Midland, and Midland agrees to pay to Vista, an
     amount of cash equal to $400,000, which amount shall be inclusive of
     expenses as set forth in Section 4.12);
 
          (f) By Vista after June 22, 1998, if on such date Midland shall not
     have received an Option Exercise Agreement executed by each of the holders
     of issued and outstanding Midland Stock Options who is an executive officer
     of director of Midland;
 
          (g) By Midland after June 22, 1998, if on such date Vista shall not
     have received an Exchange Agreement from each holder of GP Common Stock and
     each holder of a Partnership Interest.


                                      A-64
<PAGE>

     6.2 EFFECT OF TERMINATION. If this Agreement is terminated by either
Midland or Vista pursuant to the provisions of Section 6.1, this Agreement shall
forthwith become void except for, and there shall be no further obligation on
the part of any party hereto or its respective Affiliates, directors, officers,
partners, or shareholders except pursuant to, the provisions of Sections 4.12
and 6.1(e), and Article 7; provided, however, that a termination of this
Agreement shall not relieve any party hereto from any liability for damages
(excluding punitive damages which each party hereby waives the right to recover
hereunder) incurred as a result of a breach by such party of its
representations, warranties, covenants, agreements, or other obligations
hereunder occurring prior to such termination.
 
                                   ARTICLE 7
 
                                 MISCELLANEOUS
 
     7.1 AMENDMENT. This Agreement may be amended by the parties hereto at any
time before or after approval of the Midland Merger and this Agreement by the
shareholders of Midland and the Vista Exchange by the partners of Vista;
provided, however, that after any such approval, no amendment shall be made that
by law requires further approval by such shareholders or partners without such
further approval. This Agreement may not be amended except by a written
instrument signed on behalf of each of the parties hereto.
 
     7.2 EXTENSION; WAIVER. At any time prior to the Effective Time, the parties
hereto may, to the extent legally allowed, (a) extend the time for the
performance of any of the obligations or other acts of the other parties hereto,
(b) waive any inaccuracies in the representations and warranties contained
herein or in any document delivered pursuant hereto, and (c) waive performance
of any of the covenants or agreements, or satisfaction of any of the conditions,
contained herein. Any agreement on the part of a party hereto to any such
extension or waiver shall be valid only if set forth in a written instrument
signed on behalf of such party.
 
     7.3 NONSURVIVAL OF REPRESENTATIONS, WARRANTIES, COVENANTS, AND
AGREEMENTS. All representations, warranties, covenants, and agreements contained
in this Agreement or in any instrument delivered pursuant to this Agreement
shall be deemed to the extent expressly provided herein to be conditions to the
Midland Merger, and none of such representations, warranties, covenants, and
agreements shall survive the consummation of the Merger (except for the
agreements contained in Article 2, in Sections 4.12, 4.13, 4.14, 4.15, 4.16,
4.17, 4.18 and 4.20, and in this Article.
 
     7.4 NOTICES. Any notice or other communication required or permitted
hereunder shall be in writing and either delivered personally, by facsimile
transmission, or by registered or certified mail (postage prepaid and return
receipt requested) and shall be deemed given when received (or, if mailed, five
business days after the date of mailing) at the following addresses or facsimile
transmission numbers (or at such other address or facsimile transmission number
for a party as shall be specified by like notice):
 
        (a) If to Vista, Newco, or Merger Sub:
 
          Vista Energy Resources, Inc.
          550 West Texas Avenue, Suite 700
          Midland, Texas 79701
          Attention: C. Randall Hill
          Facsimile No.: (915) 688-0589
 
          with a copy to:
 
          Vinson & Elkins L.L.P.
          3700 Trammell Crow Center
          2001 Ross Avenue
          Dallas, Texas 75201-2975
          Attention: A. Winston Oxley
          Facsimile No.: (214) 220-7716


                                      A-65
<PAGE>
 
          (b) If to Midland:
 
           616 FM 1960 West
           Suite 600
           Houston, Texas 77090-3027
           Attention: Wayne M. Whitaker
           Facsimile No.: (281) 587-9052
 
           with a copy to:
 
           Law, Snakard & Gambill
           500 Throckmorton, Suite 3200
           Fort Worth, Texas 76102
           Attention: Vernon E. Rew, Jr.
           Facsimile No.: (817) 332-7473
 
     7.5 COUNTERPARTS. This Agreement may be executed in two or more
counterparts, all of which shall be considered one and the same agreement and
shall become effective when two or more counterparts have been signed by each of
the parties and delivered to the other parties, it being understood that all
parties need not sign the same counterpart.
 
     7.6 SEVERABILITY. Any term or provision of this Agreement that is invalid
or unenforceable in any jurisdiction shall, as to such jurisdiction, be
ineffective to the extent of such invalidity or unenforceability without
rendering invalid or unenforceable the remaining terms and provisions of this
Agreement or affecting the validity or enforceability of any of the terms or
provisions of this Agreement in any other jurisdiction. If any provision of this
Agreement is so broad as to be unenforceable, such provision shall be
interpreted to be only so broad as is enforceable.
 
     7.7 ENTIRE AGREEMENT; NO THIRD PARTY BENEFICIARIES. This Agreement
(together with the documents and instruments delivered by the parties in
connection with this Agreement) (a) constitutes the entire agreement and
supersedes all other prior agreements and understandings, both written and oral,
among the parties with respect to the subject matter hereof and (b) except as
provided in Section 4.13, is solely for the benefit of the parties hereto and
their respective successors, legal representatives, and assigns and does not
confer on any other person any rights or remedies hereunder.
 
     7.8 APPLICABLE LAW. This Agreement shall be governed in all respects,
including validity, interpretation, and effect, by the laws of the State of
Texas regardless of the laws that might otherwise govern under applicable
principles of conflicts of laws thereof.
 
     7.9 NO REMEDY IN CERTAIN CIRCUMSTANCES. Each party agrees that, should any
court or other competent authority hold any provision of this Agreement or part
hereof to be null, void, or unenforceable, or order any party to take any action
inconsistent herewith or not to take an action consistent herewith or required
hereby, the validity, legality, and enforceability of the remaining provisions
and obligations contained or set forth herein shall not in any way be affected
or impaired thereby, unless the foregoing inconsistent action or the failure to
take an action constitutes a material breach of this Agreement or makes this
Agreement impossible to perform, in which case this Agreement shall terminate
pursuant to Article 6. Except as otherwise contemplated by this Agreement, to
the extent that a party hereto took an action inconsistent herewith or failed to
take action consistent herewith or required hereby pursuant to an order or
judgment of a court or other competent Governmental Entity, such party shall not
incur any liability or obligation unless such party breached its obligations
hereunder or did not in good faith seek to resist or object to the imposition or
entering of such order or judgment.
 
     7.10 ENFORCEMENT OF AGREEMENT. The parties hereto agree that irreparable
damage would occur in the event that any of the provisions of this Agreement
were not performed in accordance with the terms hereof or was otherwise
breached. Accordingly, the parties hereto hereby agree that each party hereto
shall be entitled to an injunction to prevent a breach of this Agreement and
shall be entitled to specific performance of the terms and provisions hereof in
addition to any other remedy at law or in equity.


                                      A-66
<PAGE>
 
     7.11 ASSIGNMENT. Nether this Agreement nor any of the rights, interests, or
obligations hereunder shall be assigned by any of the parties hereto (whether by
operation of law or otherwise) without the prior written consent of the other
parties, except that Merger Sub may assign, in its sole discretion, any or all
of its rights, interests, and obligations hereunder to any newly-formed direct
or indirect wholly-owned corporate subsidiary of Newco. Subject to the preceding
sentence, this Agreement will be binding upon, inure to the benefit of, and be
enforceable by the parties and their respective successors and assigns.
 
     7.12 WAIVERS. Except as provided in this Agreement, no action taken
pursuant to this Agreement, including any investigation by or on behalf of any
party, shall be deemed to constitute a waiver by the party taking such action of
compliance with any representations, warranties, covenants, or agreements
contained in this Agreement. The waiver by any party hereto of a breach of any
provision hereof shall not operate or be construed as a waiver of any prior or
subsequent breach of the same or any other provisions hereof.
 
     7.13 CERTAIN PROVISIONS INAPPLICABLE. The parties hereby acknowledge and
represent that the Board of Directors of each corporate party hereto has
approved the terms of this Agreement and the consummation of the transactions
contemplated herein and that such approval is sufficient to render the
provisions of Section 203 of the DGCL and Section 13.03 of the TBCA inapplicable
to the transactions contemplated herein.
 
     7.14 TERMINATION OF LETTER OF INTENT AND CONFIDENTIALITY AGREEMENT. The
parties hereby acknowledge and agree that the Letter of Intent dated January 12,
1998 between Vista and Midland and the Confidentiality Agreement dated November
18, 1997 between Vista and Midland are hereby terminated and are of no further
force and effect.
 
                  [REMAINDER OF PAGE INTENTIONALLY LEFT BLANK]


                                      A-67
<PAGE>
 
     IN WITNESS WHEREOF. The parties have caused this Agreement to be executed
by their duly authorized representatives, effective as of the date first written
above.
 
                                            VISTA RESOURCES PARTNERS, L.P.
 
                                            By: Vista Resources I, Inc., its
                                            General Partner
 
                                            By:
                                                --------------------------------
                                            Name: C. Randall Hill
                                            Title: Chairman of the Board and
                                                   Chief Executive Officer
 
                                            MIDLAND RESOURCES, INC.
 
                                            By:
                                                --------------------------------
                                            Name:
                                                   -----------------------------
                                            Title:
                                                   -----------------------------
 
                                            VISTA ENERGY RESOURCES, INC.
 
                                            By:
                                                --------------------------------
                                            Name:
                                                   -----------------------------
                                            Title:
                                                   -----------------------------
 
                                            MIDLAND ACQUISITION CO.
 
                                            By:
                                                --------------------------------
                                            Name:
                                                   -----------------------------
                                            Title:
                                                   -----------------------------
 
                      [SIGNATURE PAGE TO MERGER AGREEMENT]


                                      A-68


<PAGE>


                                                                    EXHIBIT 10.1
                          CONTRACT OPERATING AGREEMENT

         This Contract Operating Agreement (this "Agreement") is entered into
effective as of the 1st day of June, 1998, and is by and between VISTA
RESOURCES, INC., whose address is 550 West Texas Avenue, Suite 700, Midland,
Texas 79701 ("Contractor"), and MIDLAND RESOURCES OPERATING COMPANY, INC.,
whose address is 616 FM 1960 West, Suite 600, Houston, Texas 77090 (including
it parent and affiliated companies "Owner").

1.  Effective as of June 1, 1998, Contractor, as an independent contractor,
    agrees to provide contract operating services for all of the operated 
    wells, leases, and related facilities of Owner now owned or hereinafter 
    acquired during the term of this Agreement (the "Properties"). Contractor 
    shall perform such duties and services  hereunder as and to the extent 
    requested by Owner; provided such duties and services are customarily 
    performed by contract operators in the usual course of producing and 
    maintaining oil and gas wells including the following:

      o  pumper services 
      o  field foreman assistance 
      o  engineering supervision and analysis 
      o  geological review and analysis 
      o  land and legal review and analysis 
      o  accounting and production reporting assistance

2.  It is understood and agreed that Owner shall remain the operator of record
    with the Texas Railroad Commission ("RRC") and other relevant state and 
    federal agencies such as the General Land Office, University Lands 
    Department, Texas Office of the Comptroller, the Department of Energy and 
    the Environmental Protection Agency. Accordingly, all reports and filings 
    made with such agencies shall be the responsibility of, and shall be made 
    by, Owner with such assistance from Contractor as Owner reasonably 
    requests. Likewise all accounting and production reporting functions
    (including, without limitation, all revenue tracking and distribution, 
    joint interest billing, payable and receivable functions and state
    production and tax reporting) shall remain the responsibility of, and shall
    be accomplished by, Owner with such assistance from Contractor as Owner
    reasonably requests.

1.  Owner shall pay Contractor for the work so performed and services provided
    hereunder as follows:

      o  For pumper and field foreman services - on an actual cost basis for all
         direct costs and expenses incurred by Contractor hereunder for such 
         employees (based on allocating the cost and expense of such employees
         over the Properties on a well by well basis).
<PAGE>
      o  Engineering and supervision charges for specific projects (i.e.,
         engineering or geological studies) or specific property related 
         procedures (i.e., well site work in connection with workovers, 
         recompletions, drilling activities, completions or major facilities 
         work) shall be pre-approved by Owner and shall be charged by 
         Contractor to Owner at the rate of  Four Hundred Dollars ($400.00) per
         day (with a half day minimum charge, plus reimbursement for actual out
         of pocket direct expenses incurred) for each Vista employee engaged by
         Owner to provide such services.

      o  For general and administrative services provided hereunder by 
         Contractor to Owner (including, without limitation, office space, 
         telephone, fax, office supplies and copying services provided to Owner
         by Contractor) Contractor shall charge Owner a fixed charge of $1,500
         per month through October 1998. From and after November 1, 1998, such
         charge shall be increased from $1,500 to $3,000 per month. Any general
         and administrative assistance requested by Owner over and above the 
         limited services contemplated in this subparagraph shall be billed on
         agreed upon hourly rates for the number and type of Contractor 
         employees requested by Owner.

      o  For all services rendered by Contractor for the benefit of Owner and 
         not generally described above or not specifically contemplated at the
         time of the signing of this Agreement, Contractor and Owner agree to 
         work with each other in good faith to establish a fair compensation 
         for such services on a case by case basis.

 Contractor shall submit detailed invoices for all services rendered hereunder
monthly on or before the last day of each succeeding calendar month and Owner
will remit payment within 15 business days of receipt of each proper invoice.

4.  Contractor shall not be liable for any losses or damages sustained to any
    of the Properties of Owner caused by any fire, storm, flood, explosion,
    theft or other cause whatsoever unless such loss is the result of the
    willful or grossly negligent act of Contractor or its employees. Owner
    shall, at its sole cost and expense, make all repairs and do any 
    reconditioning necessary of the Properties as it deems necessary to the
    operations of the Properties. Contractor shall make such minor mechanical
    adjustments and repairs as are ordinarily performed by a contract operator
    in the course of his regular duties, but Owner shall furnish, at its 
    expense, all material and equipment required therefor. Contractor shall
    promptly notify Owner of the need for any repairs, replacements, servicing
    or reconditioning which may be or become necessary in connection with the
    Properties.

1.  Contractor will cause to be issued and maintained a current Certificate of
    Insurance with Owner at all times during the term of this Agreement with 
    such Certificate of Insurance evidencing the insurance coverages and 
    amounts as set out on Exhibit A hereto.


                                     Page 2
<PAGE>

2.  It is understood and agreed that Contractor is acting solely as an
    independent contractor under this Agreement.  Accordingly, this Agreement
    is  not intended to create, and shall not be construed as creating, any
    assignment, assumption or transfer by Owner of any liabilities or potential
    liabilities to Contractor, and Contractor expressly does not assume any
    such liabilities. This Agreement shall not be considered as creating a
    partnership or employee/employer relationship between Contractor and Owner.

7.  At all times during the term of this Agreement, Contractor, its management,
    supervisory and support staff, and any third party consultants engaged by
    Contractor, shall have complete and total access to all books, files and 
    records of Owner, including, without limitation, all accounting, tax and 
    financial records; lease, land, division order and contract files and 
    records; well, production and operations files, data and information;
    geological and geophysical files, data, and information; reserve and
    engineering files, data and information; and all other files, data and
    information within the possession or control of Owner and in any way 
    relating to the Properties ("Owner Files and Records"). Owner authorizes
    Contractor to communicate with all accountants, auditors, attorneys,
    consultants and other parties who have heretofore performed or who may
    hereafter perform services for and on behalf of Owner to obtain from such
    parties copies of any Owner Files and Data which Contractor deems necessary
    or advisable to obtain in order to effectively perform the services
    contemplated hereunder. At any time during the term of this Agreement
    Contractor shall have the power and authority to transfer or cause the 
    transfer of the originals of the Owner Files and Data to its premises in
    Midland, Texas; provided that Owner shall have complete access thereto at
    all times during business hours.  Upon termination of this Agreement (if
    the merger between Owner and Vista Resources Partners, L.P. as contemplated
    by that certain Agreement and Plan of Merger dated May 22, 1998 has not
    occurred at such time), upon Owner's request, Contractor shall return the
    originals of the Owner Files and Data to Owner.

8.  This Agreement shall be governed by, and construed and enforced in 
    accordance with, the laws of the State of Texas, excluding any
    choice-of-law provisions thereof.

1.  This Agreement shall continue through October 31, 1998 unless otherwise     
    terminated by the agreement of both parties hereto. After October 31, 1998
    this Agreement shall continue on a month-to-month basis unless terminated
    by either party upon prior written notice of termination. If such notice of
    termination is received by the other party then this Agreement shall
    terminate on the first day of the next succeeding month after the lapse of
    30 days from the date of receipt of the notice of termination.


                                     Page 3
<PAGE>

9.  All written correspondence and communication shall be sent by first class
    U.S. mail, telecopier or hand/overnight delivery as follows:

         IF TO CONTRACTOR:

         Vista Resources, Inc.
         550 West Texas Avenue, Suite 700
         Midland, Texas 79701
         Attention: Mr. Steve Gray
         FAX (915) 688-0589

         IF TO OWNER:

         Midland Resources Operating Company, Inc.
         c/o Mr. Robert R. Donnelly, President
         415 West Wall, Suite 1415
         Midland, Texas 79701
         FAX (915) 683-6295


         EXECUTED effective as of the date set out above.




OWNER:                                             CONTRACTOR:

MIDLAND RESOURCES OPERATING                        VISTA RESOURCES, INC.
COMPANY, INC.




By:                                                By:
   -----------------------------                      ----------------------
   Robert R. Donnelly, President                      C. Randall Hill, CEO


                                     Page 4
<PAGE>

                                   EXHIBIT A


CERTIFICATE OF INSURANCE






                                     Page 5

<PAGE>

                                                                    EXHIBIT 10.2


                           WARLEY SETTLEMENT AGREEMENT

         This Warley Settlement Agreement ("Agreement") is made and entered into
as a compromise among the Parties for the complete and final settlement of their
claims, differences and alleged causes of action as set forth below.

                                     PARTIES

         The signatories to this Agreement are Midland Resources, Inc., a Texas
corporation ("Midland" and the "Company") and Deas H. Warley III ("Warley"). The
signatories to this Agreement are referred to jointly as the "Parties."

                                    PREAMBLE

         WHEREAS, Midland is in the business of acquiring, operating and
producing oil and gas properties;

         WHEREAS, Warley was hired by Midland to serve as its President at its
offices in Houston, Texas;

         WHEREAS, Warley and Midland entered into an Employment Contract dated
January 3, 1995, and an Amendment to Employment Contract dated January 8, 1996
(collectively, the "Employment Contract"), copies of which are attached as
Exhibit A;

         WHEREAS, Warley was employed continuously by Midland until March 27,
1998 (the "Separation Date"), at which time his employment with Midland was
terminated;

         WHEREAS, Warley continues to serve as a director of Midland;

         WHEREAS, Midland has concurrently entered into a definitive agreement
(the "Vista Merger Agreement") with Vista Resources Partners, L.P. ("Vista")
which contemplates generally that Midland will merge with a subsidiary of Vista
Energy Resources, Inc. ("Vista-Newco"), the shareholders and warrant holders of
Midland will receive shares and warrants, respectively, of Vista-Newco, and
that the partners of Vista will exchange their partnership interests in Vista
for shares and warrants of Vista-Newco, with Vista-Newco becoming a new publicly
held company (the "Vista Merger'");

         WHEREAS, Midland has advised Warley in writing to consult with a
lawyer;

         WHEREAS, Warley has been given a period of at least twenty-one (21)
days to consider this Agreement;

Warley Settlement Agreement                                               Page 1

<PAGE>

         WHEREAS, the Parties have consulted with independent counsel with
respect to the terms, meaning and effect of this Agreement;

         WHEREAS, Warley has represented and hereby reaffirms that he does not
believe that either he or Midland have engaged in any conduct involving Midland
that is or may be illegal in any respect, or in violation of any Midland policy,
including Midland's policy prohibiting sexual harassment;

         WHEREAS, each Party understands that the other regards the above
representations by him or it as material and that each Party is relying on these
representations in entering into this Agreement; and

         WHEREAS, the Parties intend that this Agreement, along with the
attached Exhibits, as described below, shall govern all issues related to
Warley's employment and separation from Midland.

         NOW, THEREFORE, in consideration of the mutual promises and obligations
contained in this Agreement and other good and valuable consideration, the
receipt and sufficiency of which is hereby acknowledged, the Parties agree as
follows:

1.       DEFINITIONS

         1.1      "The Company" shall mean and include Midland Resources, Inc.
and all of its predecessors, successors, affiliated companies, assigns, present
and former officers, directors, employees, shareholders, attorneys and agents,
whether in their individual or official capacities.

         1.2      "Warley" shall mean Deas H. Warley, III, and any person
claiming by, through or under him.

         1.3      The "Parties" shall mean Warley and the Company.

         1.4      "Midland" shall mean Midland Resources, Inc.

         1.5      A "Change in Control" shall be deemed to have occurred if:

         (a)      the Vista Merger or any similar or related transactions is 
                  consummated;

         (b)      the Company merges or consolidates with any other corporation
                  (other than a wholly-owned direct or indirect subsidiary of
                  the Company as of the date of this Agreement) and is not the
                  surviving corporation (or survives as a subsidiary of another
                  corporation);

         (c)      the Company sells all or substantially all of its assets to 
                  any other person or entity;

         (d)      the Company is dissolved;

Warley Settlement Agreement                                               Page 2

<PAGE>

         (e)      any third person or entity, or a trustee or committee of any
                  qualified employee benefit plan of the Company) together with
                  his, her or its affiliates shall become (by tender offer or
                  otherwise), directly or indirectly, the beneficial owner of
                  forty percent (40%) or more of the voting stock of the
                  Company;

         (f)      the individuals who constitute the Board of Directors of the
                  Company as of the Effective Date (the "Incumbent Board") shall
                  cease for any reason to constitute at least a majority of the
                  Board of Directors; except that any person becoming a director
                  whose election or nomination for election was approved by a
                  majority of the members of the Incumbent Board shall be
                  considered, for the purposes of this paragraph, a member of
                  the Incumbent Board; or

         (g)      any other event that a majority of the Board of Directors, in
                  its sole discretion, shall determine constitutes a Change in
                  Control.

         1.6      "Material Breach" shall mean a judicial determination that
either Party has unjustifiably failed or refused to perform his or its
obligations as defined in paragraphs 3 and 4 of this Agreement.

2.       EFFECTIVE DATE; REMEDIES

         2.1      The Effective Date of this Agreement shall be March 27, 1998.
This Agreement shall automatically terminate on the first to occur of (a) the
termination of the Vista Merger Agreement, or (b) December 31, 1998. Upon
termination, this Agreement shall be void and unenforceable in its entirety.

         2.2      If Warley commits a Material Breach of this Agreement, the
Parties agree that Midland shall be excused from any remaining performance under
paragraphs 3.1, 3.2, 3.3 and 3.4, and that this remedy shall be Midland's sole
remedy.

         2.3      If Midland commits a Material Breach of this Agreement, the
Parties agree that Warley may (a) accelerate the due date of all remaining
payments under paragraphs 3.1 and 3.4, so that they are immediately due and
payable, and (b) if not previously performed, recover actual damages caused by
Midland's breach of paragraphs 3.5, 3.6, 3.7, 3.8 and 3.9, or any of them, and
that these remedies shall be Warley's sole remedies.

         2.4      The prevailing Party in any proceeding to enforce or avoid the
terms of this Agreement shall be entitled to recover his or its reasonable
attorney's fees and costs from the nonprevailing Party.

3.       COMPANY'S OBLIGATIONS

         3.1      (a)     Beginning March 27, 1998, and ending on the first to
occur of (i) the effective date of the Vista Merger, (ii) the termination of the
Vista Merger Agreement or (iii) December 31,

Warley Settlement Agreement                                               Page 3

<PAGE>

1998, the Company agrees to pay Warley the sum of $11,390.82 per month, with
one-half of such sum paid on the first and fifteenth of each month, less amounts
required to be withheld by local, state or federal law, and/or other deductions
authorized by Warley in writing. If the Vista Merger occurs, then the payments
provided for in this Section 3.1(a) shall also be paid until the first payment
becomes payable under Section 3.2(b)

         (b)      On the effective date of the Vista Merger, the Company agrees
to pay to Warley the sum of $1,300,000 (the "Settlement Payment"). Warley agrees
that the Company shall reduce the Settlement Payment by the amount Warley is
obligated to pay under the Wade Release, and the Company agrees to make such
payment to Ms. Wade in accordance with the Wade Release. The remaining balance
of the Settlement Payment in the amount of $1,200,000 shall be paid in the
following manner. Beginning with a payment on the first day of the month
immediately following the effective date of the Vista Merger, and ending with a
payment on the first day of the sixtieth month from such date, the Company
agrees to pay $20,000 to Warley, less amounts required to be withheld by local,
state or federal law, and/or other deductions authorized by Warley in writing.
The Company agrees that all such payments under this 3.1(b) shall be made by
cheek payable to "Deas H. Warley III," and mailed by postage paid first class
mail to Warley's address set forth herein, and are due on the first day of each
month. If a payment does not reach Warley by the 10th day of each month, the
Company will upon written notice from Warley, issue stop payment instructions to
such missing check and immediately issue a replacement check that will be sent
to Warley's address by overnight courier service. A payment not made or sent
according to the above procedure will accrue interest at the rate of one and
one-half percent (1-1/2%) per month from the 10th day of the month in which
such payment was due until paid.

         Warley acknowledges that he has received all payments required by
Section 3.1(a) as of the execution of this Agreement.

         3.2      omitted.

         3.3      Warley shall have the option at any time up to one year after
any Change in Control to elect to receive a lump sum payment equal to the
present value (using a discount factor of six percent (6%)) of the remaining
payments due Warley under paragraph 3.1 at the time of the election. Likewise,
the Company may elect at any time after one year following the date of any
Change in Control to pay a lump sum calculated in the same manner. The lump sum
payment shall be due to Warley within ten (10) days after either Party notifies
the other in writing of his or its election under this paragraph.

         3.4      For a period beginning April 1, 1998 ending on the earlier of
(i) the termination of the Vista Merger Agreement, or (ii) September 1, 1999 the
Company shall continue to pay an amount (equal to the employer's portion of the
applicable insurance premiums) for Warley's and his current eligible dependent's
medical and dental insurance COBRA continuation coverage, which on the date
hereof is $324.36 per month.


Warley Settlement Agreement                                               Page 4

<PAGE>

         3.5      Within thirty (30) days after the date of this Agreement,
Warley shall remove from the Company's offices those personal effects described
in Exhibit B.

         3.6      The Company agrees to convey to Warley the vehicles and items
described on Exhibit C, free of all liens and encumbrances, upon any Change in
Control. Until the termination of this Agreement or a Change in Control, Warley
may continue to use those items listed on Exhibit C that are currently in his
possession.

         3.7      Warley agrees that, upon a Change in Control, all his existing
stock options for 15,000 shares of Midland's common stock at an exercise price
of $2.375 per share (the "Options"). shall expire at 5:00 p.m. on the 120th day
following such a Change in Control (including the Vista Merger), unless earlier
exercised.

         3.8      Midland agrees to reimburse Warley for all reasonable travel
expenses incident to his continuing service as a director of Midland, and any
other reasonable business expenses approved in advance by the Company.

         3.9      The Company agrees to reimburse Warley upon a Change in
Control for all legal and professional fees incurred by Warley in connection
with previous disputes between the Parties and the termination of his employment
and the preparation and negotiation of this Agreement, provided that the
Company's obligation under this paragraph shall not exceed $20,000.00.

         3.10     Midland shall return one fully executed original of this
Agreement to Warley simultaneously with the execution of the Vista Merger
Agreement.

4.       WARLEY'S OBLIGATIONS

         4.1      Simultaneously with the execution of the Vista Merger
Agreement, Warley shall execute and return to counsel for Midland two originals
of this Agreement.

         4.2      Warley agrees that he will support the Vista Merger, including
without limitation the execution of documents and the taking of, or refraining
from taking, actions, as contemplated in the Vista Merger Agreement. Warley
further agrees to support any transaction similar in form to the Vista Merger
Agreement, insofar as his support is consistent with his fiduciary duties as a
director of Midland, including the duty to exercise his informed and independent
judgment with respect to the proposed transaction.

         4.3      Warley agrees that he will not contact or communicate with any
existing Midland shareholder or warrant holder (other than existing officers,
directors of Midland), directly or indirectly, in a manner which disparages or
is intended to disparage the Vista Merger as contemplated in the Vista Merger
Agreement.

Warley Settlement Agreement                                               Page 5

<PAGE>

         4.4      Contemporaneously with the execution of this Agreement, Warley
shall execute and deliver, and thereafter comply with the terms of the Voting
Agreement. attached as Exhibit D, in his capacity as an individual shareholder
of Midland.

         4.5      Warley agrees to comply with the surviving portions of the
Employment Contract as defined in paragraph 6.2(a). The remainder of the
Employment Contract shall be void and unenforceable.

5.       RELEASE BY WARLEY

         5.1      Except as specifically set forth in Paragraph 5.3, Warley, for
himself, his attorneys, agents, heirs, executors, administrators, successors and
assigns, hereby releases, waives and discharges the Company from each and every
claim, action or right of any sort, known or unknown, absolute or contingent,
(i) arising on or before the Effective Date or (ii) any and all claims relating
to or arising from the adoption, execution and performance of the Vista Merger
Agreement and related documents insofar as the terms of such agreements and
documents exist on the date hereof. The foregoing release includes, but is not
limited to, any claim for salary, wages or benefits, any claim of discrimination
on the basis of race, sex, marital status, sexual preference, national origin,
handicap or disability, age, veteran status, or special disabled veteran status;
any other claim based on a statutory prohibition; any claim arising out of or
related to the Employment Contract, or any other express or implied employment
contract; any other contract affecting terms and conditions of employment; any
claim for breach of any covenant of good faith and fair dealing; any tort
claims; and any personal gain with respect to any claim arising under the qui
tam provisions of any state or federal law.

         5.2      Warley represents that he understands the foregoing release
provision, that rights and claims under the Age Discrimination in Employment Act
of 1967 are among the rights and claims against the Company he is releasing and
that he understands that he is not releasing any rights or claims arising after
the Effective Date, except insofar as a claim relates to or arises from the
adoption, execution and performance of the Vista Merger Agreement and related
documents insofar as the terms of such agreements and documents exist on the
date hereof.

         5.3      Warley's release does not include (a) the Company's
obligations as defined in this Agreement; or (b) Warley's right to defense and
indemnification for claims relating to his alleged actions in his capacity as an
officer or director of the Company. Warley agrees to cooperate with counsel for
the Company with respect to any litigation as to which Warley has a right of
defense or indemnification. Warley shall not be entitled to indemnification for
any payment made by, or for his benefit, pursuant to the Release and Hold
Harmless Agreement dated May 22, 1998 among Warley, the Company and Marilyn D.
Wade (the "Wade Release"), attached as Exhibit E.

Warley Settlement Agreement                                               Page 6

<PAGE>

6.       RELEASE BY COMPANY

         6.1      Except as specifically set forth in Paragraph 6.2, the Company
releases, waives and discharges Warley, his attorneys, agents, heirs, executors,
administrators, successors and assigns from each and every claim, action or
right of any sort, known or unknown, arising on or before the Effective Date.

         6.2      The Company's release does not include:

         (a)      the following provisions of the Employment Contract, which
                  shall remain in effect in accordance with their terms:

                  (i)      Paragraph 6.1 of the Employment Contract (Trade
                           Secrets);

                  (ii)     Paragraph 6.2 of the Employment Contract
                           (Confidential Information);

                  (iii)    Paragraph 6.3 of the Employment Contract (Covenant
                           not to Compete), except that if a Change In Control
                           occurs, in which event the Company agrees that this
                           portion of the Employment Contract shall be void and
                           not binding;

                  (iv)     Paragraph 6.5 of the Employment Contract (Inventions
                           and Patents).

         (b)      Warley's obligations as defined in paragraph 4 of this 
                  Agreement.

         (c)      Any claims brought by any shareholder derivatively on behalf
                  of the Company relating to or arising out of Warley's service
                  as a director of the Company.

7.       WADE RELEASE

         7.1      Midland, Warley and Marilyn D. Wade have entered into a
Release and Hold Harmless Agreement dated May 22, 1998 (the "Wade Release"),
attached as Exhibit E.

         7.2      If and when the Vista Merger is consummated, the Parties agree
that Midland shall pay, on behalf of Warley, the amount due to Wade from Warley
pursuant the Wade Release.

         7.3      Midland and Warley agree that to the extent the Company is not
adversely economically impacted, the Wade Advance shall be a tax-neutral event
for Warley.

8.       NOTICES

         8.1      All notices to Midland under this Agreement shall be sent by 
United States mail or messenger to:

                           Midland Resources, Inc.
                           Attention: Robert R. Donnelly
                           President
                           616 F.M. 1960 West
                           Suite 600
                           Houston, Texas 77090-3027

Warley Settlement Agreement                                               Page 7

<PAGE>

         8.2      All notices and payments to Warley under this Agreement shall
be sent by United States mail or messenger to:

                           Deas H. Warley III
                           8920 Woodlane
                           Magnolia, Texas 77354-5771

         8.3      Either party may change his or its address upon reasonable
written notice delivered to the other by United States mail or messenger.

9.       MISCELLANEOUS

         9.1      The Parties acknowledge and agree that this Agreement is the
result of a compromise and shall never be construed as, or said by either of
them to be, an admission by either Party of any liability, wrongdoing, or
responsibility, and the Parties expressly disclaim any such liability,
wrongdoing, fault, or responsibility.

         9.2      This Agreement and the documents referenced in it constitute
the entire agreement between the Parties. This Agreement may be executed in
identical counterparts, each of which shall constitute an original and all of
which shall constitute one and the same agreement.

         9.3      Warley represents that he has not filed or authorized the
filing of any complaints, charges to lawsuits against the Company with any
federal, state or local court, governmental agency, or administrative agency,
and that if, unbeknownst to Warley, such a complaint has been filed on his
behalf, he will use his best efforts to cause it to immediately be withdrawn and
dismissed with prejudice.

         9.4      The Company represents that it has not filed or authorized the
filing of any complaints, charges or lawsuits against the Warley with any
federal, state or local court, governmental agency, or administrative agency,
and that if, unbeknownst to the Company, such a complaint has been filed on its
behalf, it will use its best efforts to cause it to immediately be withdrawn and
dismissed with prejudice.

         9.5      This Agreement may not be modified or amended except by a
writing signed by all Parties. No waiver of this Agreement or of any of the
promises, obligations, terms, or conditions contained herein shall be valid
unless it is in writing signed by the party against whom the waiver is to be
enforced.

         9.6      If any part or any provision of this Agreement shall be
finally determined to be invalid or unenforceable under applicable law by a
court of competent jurisdiction, that part shall

Warley Settlement Agreement                                               Page 8

<PAGE>

be ineffective to the extent of such invalidity or unenforceability only,
without in any way affecting the remaining parts of the affected provision or
the remaining provisions of This Agreement.

         9.7      The Parties have cooperated in the preparation of this
Agreement and, hence, the Agreement shall not be interpreted or construed
against or in favor of any Party by virtue of the identity, interest, or
affiliation of its preparer.

         9.8      This Agreement is made and shall be enforced pursuant to the
laws of the State of Texas, and all performance required by the terms of this
Agreement shall take place in Harris County, Texas.

         9.9      The Parties warrant that no promise or representation has been
made to him or it in executing this Agreement other than those expressly stated
in the written provisions of this Agreement; and that they do not rely on any
promise, statement. or representation of the other Party or any agent of the
other Party not expressly stated in this Agreement, or on any alleged obligation
of the other Party or his or its agents to disclose any information. The Parties
further warrant that each is relying on the Party's own judgment and has been
advised by legal counsel of the Party's choice.


         9.10     The Parties further warrant that their undersigned
representatives are legally competent and fully authorized to execute and
deliver this Agreement.

DATED: May 22, 1998.

                            [SIGNATURE PAGE FOLLOWS]


Warley Settlement Agreement                                               Page 9

<PAGE>

   DEAS H. WARLEY III                     MIDLAND RESOURCES, INC.

     /s/ Deas H. Warley III               By:  /s/ Robert R. Donnelly
   ------------------------------            -----------------------------------
   Deas H. Warley III                     Printed Name: Robert R. Donnelly
   Date: May 22, 1998                     Title: President
                                          Date: May 22, 1998

Warley Settlement Agreement                                              Page 10

<PAGE>


                                    EXHIBIT A


                   EMPLOYMENT CONTRACT DATED JANUARY 3, 1995,
                                       AND
             AMENDMENT TO EMPLOYMENT CONTRACT DATED JANUARY 8, 1996















Warley Settlement Agreement                                              Page 11

<PAGE>

                               EMPLOYMENT CONTRACT


         By this Agreement effective January 1, 1995, Midland Resources, Inc., a
Texas corporation, referred to in this Agreement as "Employer," located at 602
N. Baird, Suite 200, Midland, Texas, 79701 employs Deas H. Warley III referred
to in this Agreement as "Employee," who accepts employment on the following
terms and conditions:

                         Article 1 - TERM OF EMPLOYMENT

         1.1      Term of Employment. By this Agreement, the Employer employs
the Employee, and the Employee accepts employment with the Employer, for a
period of five (5) years beginning on the 1st day of January, 1995; however,
this Agreement may be terminated earlier, as provided in Article 7, below.

                            Article 2 - COMPENSATION

         2.1      Basic Compensation. As basic compensation for all services
rendered under this Agreement, the Employee shall be paid by the Employer a
salary of $204,000 per year, payable in equal semi-monthly installments of
$8,500 during the period of employment. The amount paid is to be pro rated for
any partial employment. The basic compensation stated herein is gross salary.
Employee's basic compensation will be reviewed and increased at a minimum of
five percent (5%) semi-annually.

         2.2      Incentive Compensation. In addition to the basic compensation
hereinabove stated, the Employee may be entitled to receive incentive
compensation, including but not limited to bonuses, stock options, and stock
appreciation rights, ("Incentive Compensation") as determined from time to time
by the Compensation Committee of the Board of Directors ("Compensation
Committee") of the Employer. Any Incentive Compensation the Compensation
Committee awards Employee shall not contain any vesting or termination
provisions.

         2.3      Vacation Pay. The Employee shall be entitled to an annual
vacation leave of four weeks at full pay.

                         Article 3 - DUTIES OF EMPLOYEE

         3.1      Duties. The Employee is employed as President and agrees to
serve as an officer of Employer as determined from time to time by the
Employer's Board of Directors. The Employee shall perform all duties as may be
required of Employee by the Board of Directors from time to time during the term
of employment.

Warley Settlement Agreement                                              Page 12

<PAGE>

         3.2      Extent of Services. The Employee shall devote eighty percent 
(80%) of his productive time, ability, attention, and energies to the business
of the Employer during the term of this Agreement.

         3.3      Pilot Training. The Employee shall remain current on training
in any Employer owned aircraft the Employee may fly. Any training Employee may
need pursuant to this paragraph shall be provided by Employer.

                          Article 4 - EMPLOYEE BENEFITS

         4.1      Medical Benefits. The Employer agrees to include the Employee
and his dependents in any hospital, surgical, and medical benefit plan adopted
by the Employer and as amended and/or changed from time to time by Employer's
Board of Directors. Employer shall pay for any medical procedures not otherwise
covered by insurance up to an amount of $10,000 annually.

         4.2      Annual Physical. Employee shall receive an executive physical
annually. The expense of such physical shall be paid by Employer in addition to
those expenses covered in paragraph 4.1.

         4.3      Disability Benefit. In the event Employee is disabled in any
way that prevents him from performing the responsibilities contained herein,
Employee shall be entitled to one-half (1/2) of the compensation described in
Paragraph 2.1 herein for ten years following the date of the disability.

         4.4      Key Man Life Insurance. The Employer may elect to maintain
key-man life insurance on Employee for the term of this Agreement. The Employer
shall pay all costs associated with such policy. Employee agrees to cooperate
with any and all physical exams necessary to obtain this policy.

           Article 5 - REIMBURSEMENT OF EXPENSES INCURRED BY EMPLOYEE

         5.1      Business Expenses. The Employee shall be authorized from time
to time in the form of an operating budget approved by Employer's Board of
Directors to incur reasonable business expenses for promoting the business of
the Employer. The Employer will reimburse the Employee for all such expenses
upon the Employee's monthly presentation and itemized account of such
expenditures. Employee agrees to abide by the guidelines for reimbursable
business expenses which may be adopted by Employer's Board of Directors from
time to time.

Warley Settlement Agreement                                              Page 13

<PAGE>

                     Article 6 - PROPERTY RIGHTS OF PARTIES

         6.1      Trade Secrets. During the term of employment, the Employee
will have access to and become familiar with various trade secrets, consisting
of devices, secret inventions, processes, compilations of information, records,
and specifications, owned by the Employer and regularly used in the operation of
the business of the Employer. The Employee shall not disclose any such trade
secrets, directly or indirectly, nor use them in any way, either during the term
of this Agreement or at any time thereafter, except as required in the course of
his employment by Employer. All files, records, documents, drawings,
specifications, equipment, and similar items relating to the business of the
Employer, whether or not prepared by the Employee, shall remain the exclusive
property of the Employer and shall not be removed from the premises of the
Employer under any circumstances without the prior written consent of the
Employer.

         6.2      Confidential Information. Employee is employed by Employer in
a position of trust and confidence in which Employee will acquire confidential
information of Employer. All information relating to the business of Employer,
including but not limited to company records, the identity and addresses of
customers and suppliers of Employer, the Agreements of Employer with customers
and suppliers, including pricing information and technical and financial data
and information of Employer, or information relating to the business of Employer
or the marketing techniques and sales procedures of Employer are confidential
and shall be held in strict confidence by Employee during employment and after
the termination of employment. Employer intends for Employee to keep all
confidential information protected and undisclosed except as required by the
fulfillment of Employee's duties for Employer.

         6.3      Covenant not to Compete. Employee covenants not to compete
with Employer for a period of six (6) months immediately following the
termination of Employee's employment by Employer, in the same geographical areas
where Employer conducted its operations during the Employee's period of
employment, the proscribed competition being defined as any form of ownership
and/or participation as owner, principal, agent, partner, officer, employee,
independent contractor, consultant or shareholder holding more than ten percent
(10%) in a company engaged in the oil and gas business except in those
geographical areas where Employee already owns, either directly or indirectly,
said interests.

                  6.3.1  Ancillary Agreement. Employee acknowledges that this
         covenant not to compete is ancillary to this Agreement which Agreement
         Employee acknowledges to be enforceable in all respects.

                  6.3.2  Employer's Protectible Interests. Employee acknowledges
         that Employer has valuable relationships with Employer's customers,
         suppliers, employees, and other business relationships for which
         Employer has expended large sums of money, much Employee time and
         effort, and has made other financial commitments to create. Employee
         acknowledges that these relationships constitute legitimate business
         interests

Warley Settlement Agreement                                              Page 14


<PAGE>

         of Employer which this covenant not to compete is designed to protect
         without imposing on Employee a greater restraint than is necessary to
         protect Employer's goodwill and other legitimate business interests.

                  6.3.3  Injunctive Relief. Employee agrees that Employer will
         not have all the remedies necessary to enforce this covenant not to
         compete without injunctive relief and agrees that injunctive relief is
         available to the Employer for the enforcement of this covenant not to
         compete.

                  6.3.4  Court Costs and Attorney's Fees. The prevailing party
         in any litigation to enforce this covenant shall be entitled to costs
         of court and reasonable attorney's fees.

                  6.3.5  Reformation of Covenant. Employee agrees that if a 
         court shall find this covenant not to compete unreasonable in any
         respect the court shall reform this covenant not to compete so that
         its terms and conditions are reasonable.

         6.4      Return of Employer's Property. On the termination of
employment or whenever requested by the Employer, the Employee shall immediately
deliver to the Employer all property in the Employee's possession or under the
Employee's control belonging to Employer.

         6.5      Inventions and Patents. The Employee agrees that any
inventions, designs, improvements, and discoveries made by the Employee during
the term of his employment, solely or jointly with others, which are made with
the Employer's equipment, supplies, facilities, trade secrets, or time, or which
relate to the business of the Employer or the Employer's actual or anticipated
research or development, or which result from any work performed by the Employee
for the Employer, shall be the exclusive property of the Employer. The Employee
agrees that he will promptly and fully inform and disclose to the Employer all
such inventions, designs, improvements, and discoveries, and the Employee
promises to assign such inventions to the Employer. The Employee also agrees
that the Employer shall have the right to keep such inventions as trade secrets,
if the Employer chooses. The Employee shall assist the Employer in obtaining
patents in the United States and in all foreign countries on all inventions,
designs, improvements, and discoveries deemed patentable by the Employer, and
shall execute all documents and do all things necessary to obtain letters of
patents, to invest the company with full and extensive titles to the patents,
and to protect the patents against infringement by others.

Warley Settlement Agreement                                              Page 15

<PAGE>

                             Article 7 - TERMINATION

         7.1      Termination Prior to Expiration of Employment Term. This
Agreement may be terminated, and the Employee discharged, prior to the
expiration of its terms as set forth herein only by mutual agreement of Employee
and Employer.

         7.2      Termination by Employer for Cause. The Employer may at its
option terminate this Agreement by giving written notice of termination to the
Employee without prejudice to any other remedy to which the Employer may be
entitled at law, in equity, or under this Agreement, if the Employee:

                  7.2.1  Willfully breaches or habitually neglects the duties
         that the Employee is required to perform under the terms of this
         Agreement; or

                  7.2.2  Willfully violates reasonable and substantial rules
         governing Employee's performance, after notice in writing of the rules
         governing Employee's performance; or

                  7.2.3  Refuses to perform the duties assigned to the Employee
         by the Employer's Board of Directors; or

                  7.2.4  Is convicted of acts defined by the penial laws of the
         United States or any of the various states of the United States as a
         felony.

         7.3      Termination on Grounds other than for Good Cause. This
Agreement shall immediately on the occurrence of any one of the following events
without cause:

                  7.3.1  The occurrence of circumstances that make it impossible
         for the business of the Employer to be continued; or

                  7.3.2  The death of the Employee; or

                  7.3.3  The continued incapacity on the part of the Employee to
         perform his duties for a continuous period of 180 days, unless waived
         by the Employer; or

                  7.3.4  Employer has a receiver of the Employer's assets or
         property appointed because of Employer's insolvency; or

                  7.3.5  Employer makes a general assignment for the benefit of
         Employer's creditors.

         7.4      Effective Termination. In the event of the termination of this
Agreement prior to the completion of the term of employment specified in it, for
any of the reasons set forth in

Warley Settlement Agreement                                              Page 16

<PAGE>

Article 7, save and except Paragraph 7.2, the Employee shall be entitled to the
full compensation due employee under the terms of this contract.

                         Article 8 - GENERAL PROVISIONS

         8.1      Notices. All notices or other communications required under
this Agreement may be effected either by personal delivery in writing or by
certified mail, return receipt requested. Notice shall be deemed to have been
given when delivered or mailed to the parties at their respective addresses as
set forth above or when mailed to the last address provided in writing to the
other party by the addressee.

         8.2      Governing Law. This Agreement shall be governed by and
construed in accordance with the laws of the State of Texas, specifically
including without limitation the covenant not to compete contained in this
Agreement.

         8.3      Venue. This Agreement is performable in Midland County, Texas.

         8.4      Agreement to Submit to Arbitration on Written Request. Any
controversy between the parties to this Agreement involving the construction or
application of any of the terms, covenants, or conditions of this Agreement,
shall on the written request of one party served on the other, be submitted to
arbitration. Arbitration shall comply with and be governed by the provisions of
the Texas General Arbitration Act, Articles 224 through 238-6 of the Revised
Civil Statutes of Texas. Each of the parties to this Agreement shall appoint one
person as an arbitrator to hear and determine the dispute, and if they shall be
unable to agree, then the two arbitrators so chosen shall select a third
impartial arbitrator whose decision shall be final and conclusive upon the
parties to this Agreement. The expenses of arbitration proceedings conducted
pursuant to this paragraph shall be borne by the parties in such proportions as
the arbitrators shall decide.

         8.5      Entirety. This Agreement constitutes the entire understanding
between the parties. No Agreements, representations, or warranties other than
those specifically set forth in this Agreement shall be binding on any of the
parties unless set forth in writing and signed by both parties. This Agreement
supersedes all other prior agreements, either oral or in writing, between the
parties with respect to the employment of the Employee by the Employer and
contains all of the covenants and agreements between the parties with respect to
such employment in any manner. Each party to this Agreement acknowledges that no
inducements or promises, oral or otherwise, have been made by any party, or
anyone acting on behalf of any party, that are not embodied in this Agreement.

         8.6      Modification. This Agreement shall not be amended, modified,
or altered in any manner except in writing signed by both parties.

Warley Settlement Agreement                                              Page 17

<PAGE>

         8.7      Assignment. The Employer and Employee acknowledge that the
services to be rendered by the Employee under this Agreement are unique and
personal. Therefore, neither party may assign any rights or delegate any duties
under this Agreement, without the other party's prior written consent. If either
the Employer or the Employee obtains a consent to an assignment of rights or
delegations of duties, rights or duties under this Agreement it shall inure only
to the benefit of the assignee or delegee named in the written instrument, and
such consent shall not be deemed as a general consent to assignment or
delegation.

EXECUTED at Midland, Texas on January 3, 1995.

EMPLOYER
Board of Directors
Midland Resources, Inc.

         /Abstained/                        /s/ Sal J. Pagano
- ------------------------------------        ------------------------------------
Deas H. Warley III - Chairman               Sal J. Pagano, Director




/s/ Darrell M. Dillard                      /s/ Guy M. Farmer
- ------------------------------------        ------------------------------------
Darrell M. Dillard, Director                         Guy M. Farmer, Director
Compensation Committee Member                        Vice President




/s/ Robert R. Donnelly
- ------------------------------------
Robert R. Donnelly, Director
Compensation Committee Member



EMPLOYEE



 /s/ Deas H. Warley III
- ------------------------------------
Deas H. Warley III

Warley Settlement Agreement                                              Page 18

<PAGE>

                        AMENDMENT TO EMPLOYMENT CONTRACT

         This Amendment to Employment Contract ("Amendment") effective January
1, 1996, by and between Midland Resources, Inc., a Texas corporation, referred
to in this Amendment as "Employer", located at 16701 Greenspoint Park Drive,
Suite 200, Houston, Texas 77060 and Deas H. Warley III referred to in this
Agreement as "Employee".

                                   WITNESSETH:

         WHEREAS, the Employer and the Employee desire to amend the terms of the
Employment Contract (the "Agreement") between them effective January 1, 1995;

         NOW, THEREFORE, in consideration of the premises and mutual covenants
hereinafter set forth, the parties agree to amend the Agreement as follows:

1.       TERM OF EMPLOYMENT. The term of the Agreement, as set forth in
paragraph 1.1 thereof is hereby extended through December 31, 2000. On the
anniversary of the effective date of this Amendment, the term of the Agreement
shall be automatically extended for an additional period of one (1) year;
provided that (i) the Employee is employed by the Employer on such anniversary
and (ii) neither party has, within three (3) months prior to such anniversary
given the other party written notice that the Agreement shall not be
automatically extended thereafter.

2.       RATIFICATION. Except as herein amended, the provision of the Agreement
remain in full force and effect and are hereby ratified and confirmed.

EXECUTED at Houston, Texas this 8th of January, 1996.

                  EMPLOYER

                                    By: /s/ Deas H. Warley III
                                        ----------------------------------------
                                             Deas H. Warley III - President

                                    By: /s/ Sam R. Brock
                                        ----------------------------------------
                                             Sam R. Brock, Director
                                             Compensation Committee Member

                                    By: /s/ Robert R. Donnelly
                                        ----------------------------------------
                                             Robert R. Donnelly, Director
                                             Compensation Committee Member


                  EMPLOYEE

                                    By: /s/ D.H. Warley III
                                        ----------------------------------------
                                             Deas H. Warley III

Warley Settlement Agreement                                              Page 19

<PAGE>

                                    EXHIBIT B

                    SCHEDULE OF PERSONAL FURNITURE, EQUIPMENT
                      AND EFFECTS TO BE RETURNED TO WARLEY


<TABLE>
<CAPTION>
- -----------------------------------------------------------------------------------------------------
Line          Quantity        Description                                                 Serial. No.
- -----------------------------------------------------------------------------------------------------
<C>           <C>             <C>                                                         <C>
1             1               1
- -----------------------------------------------------------------------------------------------------
2             1               Harley-Davidson (HD) Piggy Bank
- -----------------------------------------------------------------------------------------------------
3             1               HD Beer Mug
- -----------------------------------------------------------------------------------------------------
4             1               HD Motorcycle Model
- -----------------------------------------------------------------------------------------------------
5             1               Radio Shack Model
- -----------------------------------------------------------------------------------------------------
6             1               Wanted Women Poster
- -----------------------------------------------------------------------------------------------------
7             1               MRI Belt Buckle
- -----------------------------------------------------------------------------------------------------
8             1               Hanley Paperweight
- -----------------------------------------------------------------------------------------------------
9             1               Texas Brass Paperweight with base
- -----------------------------------------------------------------------------------------------------
10            1               HD Big Book
- -----------------------------------------------------------------------------------------------------
11            6               Photo with Frames
- -----------------------------------------------------------------------------------------------------
12            1               Solar Pump Jack
- -----------------------------------------------------------------------------------------------------
13            1               IPAA Paperweight
- -----------------------------------------------------------------------------------------------------
14            3               HD Replica Models
- -----------------------------------------------------------------------------------------------------
15                            Aviation Books
- -----------------------------------------------------------------------------------------------------
16                            Misc. Engineering Books
- -----------------------------------------------------------------------------------------------------
17            1               Propeller Clock
- -----------------------------------------------------------------------------------------------------
18            1               Wall Clock
- -----------------------------------------------------------------------------------------------------
19            1               Signed Football
- -----------------------------------------------------------------------------------------------------
20            1               Nolan Ryan Signed Baseball
- -----------------------------------------------------------------------------------------------------
21            1               Swordfish Wood Sculpture
- -----------------------------------------------------------------------------------------------------
22            1               HD Illustrated Book
- -----------------------------------------------------------------------------------------------------
23            1               C.M. Russell - West Book
- -----------------------------------------------------------------------------------------------------
24            6               Framed Certificates
- -----------------------------------------------------------------------------------------------------
25            3               Duck Stamp Pictures
- -----------------------------------------------------------------------------------------------------
26            1               MG Picture
- -----------------------------------------------------------------------------------------------------
27            1               Mounted Pheasant
- -----------------------------------------------------------------------------------------------------
28            1               Framed Portrait
- -----------------------------------------------------------------------------------------------------
29            1               HD Mug
- -----------------------------------------------------------------------------------------------------
30            1               Electric Shoe Shine Machine
- -----------------------------------------------------------------------------------------------------
31            1               Wood Whale Carving
- -----------------------------------------------------------------------------------------------------
32            1               Love Brass Paperweight
- -----------------------------------------------------------------------------------------------------
33            1               Desk Set
- -----------------------------------------------------------------------------------------------------
34            1               Framed Photo
- -----------------------------------------------------------------------------------------------------
</TABLE>

Warley Settlement Agreement                                              Page 20

<PAGE>

                                    EXHIBIT C

                   SCHEDULE OF ITEMS TO BE CONVEYED TO WARLEY


<TABLE>
<CAPTION>
- -----------------------------------------------------------------------------------------------------
Line          Quantity        Description                                                 Serial. No.
- -----------------------------------------------------------------------------------------------------
<C>           <C>             <C>                                                         <C>
1             1               1992 Cadillac Seville                                       1G6KY529uPU
                                                                                          829556
- -----------------------------------------------------------------------------------------------------
2             1               1997 Dodge Ram Pickup Truck                                 337KC23Z7V
                                                                                          M577408
- -----------------------------------------------------------------------------------------------------
3             1               Utility Trailer                                             Lic. 87SLDC
- -----------------------------------------------------------------------------------------------------
4             1               HP Series 4M-                                               JPFG002328
- -----------------------------------------------------------------------------------------------------
5             1               NEC Monitor                                                 3X02125CA
- -----------------------------------------------------------------------------------------------------
6             1               Computer                                                    840RC
- -----------------------------------------------------------------------------------------------------
7             1               HP 870Cse                                                   SG6BJ141ZZ
- -----------------------------------------------------------------------------------------------------
8             2               File Cabinets
- -----------------------------------------------------------------------------------------------------
9             1               Storage Cabinet
- -----------------------------------------------------------------------------------------------------
10            1               Secretary's Desk
- -----------------------------------------------------------------------------------------------------
11            1               Secretary's Credenza
- -----------------------------------------------------------------------------------------------------
12            1               Secretary's Desk
- -----------------------------------------------------------------------------------------------------
13            1               Secretary's Bookcase
- -----------------------------------------------------------------------------------------------------
14            1               Secretary's Computer Table
- -----------------------------------------------------------------------------------------------------
15            1               Cellular Phone and docking Station
- -----------------------------------------------------------------------------------------------------
16            1               Executive Desk - DHW Office
- -----------------------------------------------------------------------------------------------------
17            1               Executive Chair - DHW Office
- -----------------------------------------------------------------------------------------------------
18            1               Wood Floormat - DHW Office
- -----------------------------------------------------------------------------------------------------
19            1               Executive Credenza - DHW office
- -----------------------------------------------------------------------------------------------------
20            1               Computer Table - DHW office
- -----------------------------------------------------------------------------------------------------
21            1               Work table - DHW office
- -----------------------------------------------------------------------------------------------------
22            1               Storage Cabinets - DHW office
- -----------------------------------------------------------------------------------------------------
23            1               Wood Bookcases - DHW office
- -----------------------------------------------------------------------------------------------------
</TABLE>

Warley Settlement Agreement                                              Page 21

<PAGE>

                                    EXHIBIT D

                                VOTING AGREEMENT

        Filed as Exhibit 9.1 to Vista Energy Resources, Inc.'s Registration 
Statement on Form S-4
















Warley Settlement Agreement                                              Page 22

<PAGE>

                                    EXHIBIT E

                   RELEASE AND HOLD HARMLESS AGREEMENT BETWEEN
                            MIDLAND, WARLEY AND WADE
                               DATED MAY 22 , 1998







                                  CONFIDENTIAL

        Filed as Exhibit 10.3 to Vista Energy Resources, Inc.'s Registration 
Statement on Form S-4




Warley Settlement Agreement                                              Page 23

<TABLE> <S> <C>

<PAGE>
<ARTICLE> 5
       
<S>                             <C>
<PERIOD-TYPE>                   6-MOS
<FISCAL-YEAR-END>                          DEC-31-1998
<PERIOD-START>                             JAN-01-1998
<PERIOD-END>                               JUN-30-1998
<CASH>                                          56,673
<SECURITIES>                                         0
<RECEIVABLES>                                  688,296
<ALLOWANCES>                                         0
<INVENTORY>                                          0
<CURRENT-ASSETS>                             1,138,585
<PP&E>                                      29,787,275
<DEPRECIATION>                              16,613,114
<TOTAL-ASSETS>                              16,907,032
<CURRENT-LIABILITIES>                        1,626,529
<BONDS>                                      9,061,873
                                0
                                          0
<COMMON>                                         4,468
<OTHER-SE>                                   6,214,162
<TOTAL-LIABILITY-AND-EQUITY>                16,907,032
<SALES>                                      2,182,394
<TOTAL-REVENUES>                             2,273,832
<CGS>                                        1,416,724
<TOTAL-COSTS>                                2,714,333
<OTHER-EXPENSES>                                     0
<LOSS-PROVISION>                                     0
<INTEREST-EXPENSE>                             416,759
<INCOME-PRETAX>                              (857,260)
<INCOME-TAX>                                 (291,491)
<INCOME-CONTINUING>                          (565,769)
<DISCONTINUED>                                       0
<EXTRAORDINARY>                                      0
<CHANGES>                                            0
<NET-INCOME>                                 (565,769)
<EPS-PRIMARY>                                    (.13)
<EPS-DILUTED>                                    (.13)
        

</TABLE>


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