<PAGE>   1
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                                  UNITED STATES
                       SECURITIES AND EXCHANGE COMMISSION
                             Washington, D.C. 20549


                                    FORM 10-Q


               QUARTERLY REPORT PURSUANT TO SECTION 13 OR 15(d) OF
                       THE SECURITIES EXCHANGE ACT OF 1934
                  FOR THE QUARTERLY PERIOD ENDED MARCH 31, 1998


                        COMMISSION FILE NUMBER 333-12707


                              MARINER ENERGY, INC.
             (Exact name of registrant as specified in its charter)


              DELAWARE                                         86-0460233
   (State or other jurisdiction of                          (I.R.S. Employer
   incorporation or organization)                        Identification Number)


                       580 WESTLAKE PARK BLVD., SUITE 1300
                              HOUSTON, TEXAS 77079
           (Address of principal executive offices including Zip Code)


                                 (281) 584-5500
                         (Registrant's telephone number)



     Indicate by check mark whether the registrant (1) has filed all reports 
required to be filed by Section 13 or 15(d) of the Securities Exchange Act of
1934 during the preceding 12 months (or for such shorter period that the
registrant was required to file such reports), and (2) has been subject to such
filing requirement for the past 90 days. Yes ___ No _X_

     Note: The Company is not subject to the filing requirements of the
     Securities Exchange Act of 1934. This quarterly report is filed pursuant to
     contractual obligations imposed on the Company by an Indenture, dated as of
     August 1, 1996, under which the Company is the issuer of certain debt.

        As of May 13, 1998, there were 1,000 shares of the registrant's common
stock outstanding.
-------------------------------------------------------------------------------




<PAGE>   2



                              MARINER ENERGY, INC.
                                    FORM 10-Q
                                 MARCH 31, 1998

                                TABLE OF CONTENTS
<TABLE>
<CAPTION>
                                                                                                           Page
                                                                                                           ----
<S>                                                                                                        <C>
PART I - FINANCIAL INFORMATION

Item 1.  Balance Sheets at March 31, 1998 (unaudited) and December 31, 1997...............................  1

         Statements of Operations for the three months ended March 31, 1998 and 1997 (unaudited)........... 2

         Statements of Cash Flows for the three months ended March 31, 1998 and 1997 (unaudited)........... 3

         Notes to Financial Statements..................................................................... 4

         Independent Certified Public Accountants' Report on Review of Interim Financial Information....... 5

Item 2.  Management's Discussion and Analysis of Financial Condition and Results of Operations............. 6

Item 3.  Quantitative and Qualitative Disclosures about Market Risk....................................... 10


PART II - OTHER INFORMATION

Item 1.  Legal Proceedings................................................................................ 11

Item 2.  Changes in Securities............................................................................ 11

Item 3.  Defaults Upon Senior Securities.................................................................. 11

Item 4.  Submission of Matters to a Vote of Security Holders.............................................. 11

Item 5.  Other Information...............................................................................  11

Item 6.  Exhibits and Reports on Form 8-K................................................................. 11


SIGNATURE ................................................................................................ 12
</TABLE>




<PAGE>   3



                      PART I, ITEM 1. MARINER ENERGY, INC.
                                 BALANCE SHEETS
                                 (IN THOUSANDS)
<TABLE>
<CAPTION>

                                                                                         March 31,           December 31,
                                                                                            1998                 1997
                                                                                         ---------           ------------
                                                                                        (Unaudited)
<S>                                                                                     <C>                  <C>
                            ASSETS
CURRENT ASSETS:
    Cash and cash equivalents                                                            $  (2,253)            $  9,131
    Receivables                                                                             27,742               18,585
    Prepaid expenses and other                                                               4,401                3,628
                                                                                         ---------            ---------

              Total current assets                                                          29,890               31,344
                                                                                         ---------            ---------

PROPERTY AND EQUIPMENT:
    Oil and gas properties, at full cost:
              Proved                                                                       237,849              222,829
              Unproved, not subject to amortization                                         49,733               36,526
                                                                                         ---------             --------
                    Total                                                                  287,582              259,355
    Other property and equipment                                                             2,265                2,222
    Accumulated depreciation, depletion and amortization                                   (92,493)             (84,236)
                                                                                         ---------             --------
              Total property and equipment, net                                            197,354              177,341
                                                                                         ---------             --------

OTHER ASSETS, NET OF AMORTIZATION                                                            3,954                3,892
                                                                                         ---------             --------

TOTAL ASSETS                                                                              $231,198             $212,577
                                                                                         =========             ========

              LIABILITIES AND STOCKHOLDER'S EQUITY
CURRENT LIABILITIES:
    Accounts payable                                                                      $  2,865             $  5,556
    Accrued liabilities                                                                     26,580               29,908
    Accrued interest                                                                         1,852                4,443
                                                                                         ---------             --------
              Total current liabilities                                                     31,297               39,907
                                                                                         ---------             --------

OTHER LIABILITIES                                                                            5,114                1,922

LONG-TERM DEBT:
    Subordinated notes                                                                      99,586               99,574
    Revolving Credit Facility                                                               41,000               14,000
                                                                                         ---------             --------
              Total long-term debt                                                         140,586              113,574
                                                                                         ---------             --------

STOCKHOLDER'S EQUITY:
    Common stock, $1 par value; 1,000 shares authorized,
                  issued and outstanding                                                         1                    1
    Additional paid-in-capital                                                              96,075               96,075
    Accumulated deficit                                                                    (41,875)             (38,902)
                                                                                         ---------             --------
              Total stockholder's equity                                                    54,201               57,174
                                                                                         ---------             --------

TOTAL LIABILITIES and STOCKHOLDER'S EQUITY                                                $231,198             $212,577
                                                                                          ========             ========
</TABLE>

              The accompanying notes are an integral part of these
                             financial statements.

                                       1
<PAGE>   4





                              MARINER ENERGY, INC.
                      STATEMENTS OF OPERATIONS (UNAUDITED)
                                 (IN THOUSANDS)


<TABLE>
<CAPTION>
                                                     Three Months Ended March 31,
                                                     ----------------------------
                                                        1998             1997
                                                      --------         --------
<S>                                                  <C>              <C>
REVENUES:
   Oil sales                                          $  3,366         $  2,948
   Gas sales                                            11,349           10,735
                                                      --------         --------
          Total revenues                                14,715           13,683
                                                      --------         --------
COSTS AND EXPENSES:
   Lease operating expenses                              2,811            2,479
   Depreciation, depletion and amortization              8,386            7,229
   Impairment of oil and gas properties                     --           28,514
   General and administrative expenses                     794              538
   Provision for litigation                              2,960               --
                                                      --------         --------
          Total costs and expenses                      14,951           38,760
                                                      --------         --------
OPERATING INCOME (LOSS)                                   (236)         (25,077)
INTEREST:
   Other income                                            130               84
   Other expense                                        (2,867)          (2,639)
                                                      --------         --------
INCOME (LOSS) BEFORE INCOME TAXES                       (2,973)         (27,632)
PROVISION FOR INCOME TAXES                                  --               --
                                                      --------         --------
NET INCOME (LOSS)                                     $ (2,973)        $(27,632)
                                                      ========         ========
</TABLE>


              The accompanying notes are an integral part of these
                             financial statements.


                                       2
<PAGE>   5

                              MARINER ENERGY, INC.
                      STATEMENTS OF CASH FLOWS (UNAUDITED)
                                 (IN THOUSANDS)
<TABLE>
<CAPTION>

                                                                                  Three Months Ended March 31,
                                                                                  ----------------------------
                                                                                    1998                1997
                                                                                  --------            --------
<S>                                                                              <C>                 <C>
OPERATING ACTIVITIES:
    Net income (loss)                                                             $ (2,973)           $(27,632)
    Adjustments to reconcile net income (loss) to
       net cash provided by operating activities:
                Depreciation, depletion and amortization                             8,614               7,438
                Impairment of oil and gas properties                                    --              28,514
                  Provision for litigation                                           2,960                  --
    Changes in operating assets and liabilities:
                Receivables                                                         (9,157)              3,579
                Other current assets                                                  (773)                235
                Other assets                                                          (175)                 --
                Accounts payable and accrued liabilities                            (8,610)             (4,287)
                                                                                  --------            --------
                      Net cash provided by (used for) operating activities         (10,114)              7,847
                                                                                  --------            --------
INVESTING ACTIVITIES:
    Additions to oil and gas properties                                            (28,227)             (9,915)
    Additions to other property and equipment                                          (43)               (253)
                                                                                  --------            --------
                      Net cash used for investing activities                       (28,270)            (10,168)
                                                                                  --------            --------
FINANCING ACTIVITIES:
    Payment of debt issue costs                                                         --                 (28)
    Proceeds from revolving credit facility                                         27,000                  --
                                                                                  --------            --------
                      Net cash provided by (used for) financing activities          27,000                 (28)
                                                                                  --------            --------
INCREASE (DECREASE) IN CASH AND CASH EQUIVALENTS                                   (11,384)             (2,349)
CASH AND CASH EQUIVALENTS AT BEGINNING OF PERIOD                                     9,131              10,819
                                                                                  --------            --------
CASH AND CASH  EQUIVALENTS AT END OF PERIOD                                       $ (2,253)(*)        $  8,470
                                                                                  ========            ========
</TABLE>



(*) Negative amount represents outstanding checks in 
    excess of short-term investments.


              The accompanying notes are an integral part of these
                             financial statements.


                                       3


<PAGE>   6



                              MARINER ENERGY, INC.
                          NOTES TO FINANCIAL STATEMENTS
                                   (UNAUDITED)

1.  Basis of Presentation

    The financial statements of Mariner Energy, Inc. (the "Company") included
herein have been prepared, without audit, pursuant to the rules and regulations
of the Securities and Exchange Commission ("SEC"). Accordingly, they reflect all
adjustments (consisting only of normal, recurring accruals) which are, in the
opinion of management, necessary for a fair presentation of the financial
results for the interim periods. Certain information and notes normally included
in financial statements prepared in accordance with generally accepted
accounting principles have been condensed or omitted pursuant to such rules and
regulations, although the Company believes that the disclosures are adequate to
make the information presented not misleading. These financial statements should
be read in conjunction with the financial statements and notes thereto included
in the Company's 10-K for the year ended December 31, 1997.

2.  Oil and Gas Properties

    Under the full cost method of accounting for oil and gas properties, the net
carrying value of proved oil and gas properties is limited to an estimate of the
future net revenues, discounted at 10%, from proved oil and gas reserves based
on period-end prices and costs plus the lower of cost or estimated fair value of
unproved properties. As a result of this limitation and reduced product prices
in March 1997, a non-cash full cost ceiling test impairment charge of $28.5
million was recorded in the quarter ended March 31, 1997. Price increases
subsequent to March 31, 1997 were sufficient to avoid the impairment charge,
but, given the unpredictable volatility of future prices, the Company elected to
record the charge in order to conservatively state the book value of its assets.
No impairment charge was required at March 31, 1998.

3.  Revolving Credit Facility

    Following the semi-annual borrowing base redetermination review, effective
May 4, 1998, the borrowing base under the Company's revolving credit facility
(the "Revolving Credit Facility") with NationsBank of Texas, N.A. as agent for a
group of lenders increased from $58 million to $60 million.

4.  Hedging Program

    The Company has entered into crude oil and natural gas price swaps or other
similar hedging transactions to reduce its exposure to price reductions. In the
first quarter of 1998, the Company hedged 27% of its natural gas production and
none of its crude oil production, the results of which were included in oil and
gas revenues. At March 31, 1998, the Company had natural gas hedging contracts,
including related basis differentials, in place for April through October 1998
with notional volumes of 40,000 Mmbtu per day at $2.33 per Mmbtu.

5.  Provision for Litigation

    As reported in the Company's 1997 10-K, Mariner Energy is the defendant in
litigation in the district court of Hardin County, Texas in which the plaintiff,
ETOCO, Inc., sought damages of $8.2 million plus court costs related to the
Company's operations in the Sandy Lake field. On April 22, 1998, the jury
returned a verdict partially in favor of the plaintiff in the amount of $2.4
million, before attorney's fees and interest. The Company strongly disagrees
with the jury verdict, and will vigorously contest the verdict in the trial
court and then, if necessary, in the appellate courts. In the first quarter of
1998, a $3.0 million charge was recorded to provide for this litigation-related
cost contingency. Results of the contested verdict should be known within 12 to
24 months.



                                       4

<PAGE>   7



                INDEPENDENT CERTIFIED PUBLIC ACCOUNTANTS' REPORT
                   ON REVIEW OF INTERIM FINANCIAL INFORMATION


Board of Directors and Stockholder
Mariner Energy, Inc.
Houston, Texas


We have reviewed the accompanying balance sheet of Mariner Energy, Inc. as of
March 31, 1998 and the related statements of operations and cash flows for the
three-month periods ended March 31, 1998 and 1997. These financial statements
are the responsibility of the Company's management.

We conducted our review in accordance with standards established by the American
Institute of Certified Public Accountants. A review of interim financial
information consists primarily of applying analytical procedures to financial
data and making inquiries of persons responsible for financial and accounting
matters. It is substantially less in scope than an audit conducted in accordance
with generally accepted auditing standards, the objective of which is the
expression of an opinion regarding the financial statements taken as a whole.
Accordingly, we do not express such an opinion.

Based on our review, we are not aware of any material modifications that should
be made to the accompanying consolidated financial statements for them to be in
conformity with generally accepted accounting principles.

We have previously audited, in accordance with generally accepted auditing
standards, the balance sheet as of December 31, 1997, and the related statements
of operations, stockholder's equity, and cash flows for the year ended December
31, 1997 (not presented herein), and in our report dated March 20, 1998, we
expressed an unqualified opinion on those financial statements. In our opinion,
the information set forth in the accompanying balance sheet as of December 31,
1997 is fairly stated, in all material respects, in relation to the balance
sheet from which it has been derived.


/s/ DELOITTE & TOUCHE LLP

DELOITTE & TOUCHE LLP


Houston, Texas
May 13, 1998



                                       5



<PAGE>   8



PART I, ITEM 2.   MANAGEMENT'S DISCUSSION AND ANALYSIS OF FINANCIAL CONDITION
                     AND RESULTS OF OPERATIONS.

    The following review of operations for the three month periods ended March
31, 1998 and 1997 should be read in conjunction with the financial statements of
the Company and Notes thereto included elsewhere in this Form 10-Q and with the
Financial Statements, Notes and Management's Discussion and Analysis of
Financial Condition and Results of Operations included in the Company's Annual
Report on Form 10-K for the year ended December 31, 1997, filed with the
Securities and Exchange Commission on March 30, 1998.

INFORMATION REGARDING FORWARD LOOKING STATEMENTS

    All statements other than statements of historical fact included in this
quarterly report on Form 10-Q, including, without limitation, statements
contained in this "Management's Discussion and Analysis of Financial Condition
and Results of Operations" regarding the Company's financial position, business
strategy, plans and objectives of management of the Company for future
operations and industry conditions, are forward-looking statements. Although the
Company believes that the expectations reflected in such forward-looking
statements are reasonable, it can give no assurance that such expectations will
prove to have been correct, and actual results could differ materially from the
Company's expectations. Factors that could influence these results include, but
are not limited to, oil and gas price volatility, results of future drilling,
availability of drilling rigs, and future production and costs.




                                       6

<PAGE>   9



RESULTS OF OPERATIONS

The following table sets forth certain information regarding results of
operations for the periods shown:


                                                     Three Months Ended
                                               ----------------------------
                                                  March 31,       March 31,
                                                    1998            1997
                                               --------------    ----------

Total revenue, $MM                                 $ 14.7          $ 13.7

EBITDA, $MM (a)                                      11.1            10.7

Impairment of oil & gas properties (b)                  -            28.5

Net  income (loss), $MM                              (3.0)          (27.6)

Production:
     Oil and condensate (Mbbls)                       231             164
     Natural gas (Mmcf)                             4,644           4,166
     Natural gas equivalents (Mmcfe)                6,032           5,150

Average sales prices post-hedging:
     Oil and condensate ($/Bbl)                    $14.56          $17.97
     Natural gas ($/Mcf)                             2.40            2.58
     Natural gas equivalents ($/Mcfe)                2.44            2.66

Cash Margin (c) per Mcfe:
     Revenue (pre-hedge)                            $2.45           $3.17
     Hedging impact                                 (0.01)          (0.51)
     Lease operating expenses                       (0.47)          (0.48)
     Gross G&A costs                                (0.37)          (0.26)
                                                   ------          ------
         Cash Margin                               $ 1.60          $ 1.92
                                                   ======          ======

Capital Expenditures, $MM:
    Exploration                                    $ 21.1          $  5.1
    Development & other                               7.2             5.1
                                                   ------          ------
        Total                                      $ 28.3          $ 10.2
                                                   ======          ======

(a) - EBITDA equals earnings before interest, income taxes, depreciation,
depletion, amortization, provision for litigation and impairment of oil and gas
properties. EBITDA should be used as a supplement to, and not as a substitute
for, net earnings and net cash provided by operating activities (as disclosed in
the financial statements) in analyzing the Company's results of operations and
liquidity. 

(b) - See Note 2 to Financial Statements in Item 1. of this report on Form 10-Q
for further explanation of the ceiling test impairment charges. 

(c) - Cash margin measures the net cash generated by a company's operations
during a given period, without regard to the period such cash is physically
received or spent by the company. Cash margin should be used as a supplement to,
and not as a substitute for, net earnings and net cash provided by operating
activities (as disclosed in the financial statements) in analyzing the Company's
results of operations and liquidity.



                                       7


<PAGE>   10



RESULTS OF OPERATIONS FOR THE FIRST QUARTER OF 1998

    NET PRODUCTION increased 17% to 6.0 Bcfe for the first quarter of 1998 from
5.1 Bcfe for the first quarter of 1997. Production increased due to the
completion of the Sandy Lake processing plant expansion in early 1997 and
initial production in the first quarter of 1998 from two offshore 1996
discoveries.

    OIL AND GAS REVENUES increased 7% to $14.7 million for the first quarter of
1998 from $13.7 million for the first quarter of 1997. The increase was the
result of higher production discussed above, offset partially by a decrease in
realized oil and gas prices (on an equivalent Mcf basis) between the two
quarters, net of hedging. Hedging activities for the first quarter of 1998
decreased the average realized sales price received per Mcfe by $0.01 and
revenues by $0.1 million. In the first quarter of 1997, hedging activities
decreased the average realized sales price received by $0.51 per Mcfe and
revenues by $2.6 million. During the first quarter of 1998, approximately 21% of
the Company's equivalent production was subject to hedge positions, compared
with approximately 79% for the same quarter in 1997.

    LEASE OPERATING EXPENSES increased 12% to $2.8 million for the first quarter
of 1998, from $2.5 million for the first quarter of 1997, due primarily to the
increased production discussed above.

    DEPRECIATION, DEPLETION AND AMORTIZATION EXPENSE (DD&A) increased 17% to
$8.4 million for the first quarter of 1998, from $7.2 million for the first
quarter of 1997, as a result of the 17% increase in equivalent volumes produced,
which was partially offset by a 1% decrease in the unit-of-production
depreciation, depletion and amortization rate to $1.39 per Mcfe from $1.40 per
Mcfe. The lower rate for the first quarter of 1998 was primarily due to the
$28.5 million non-cash full cost ceiling test impairment recorded at the end of
the first quarter of 1997.

    GENERAL AND ADMINISTRATIVE EXPENSES, which are net of overhead
reimbursements received by the Company from other working interest owners,
increased 60% to $0.8 million for the first quarter of 1998, from $0.5 million
for the first quarter of 1997, due primarily to increased personnel related
costs in 1998 and lower overhead reimbursement from drilling program partners.

    PROVISION FOR LITIGATION of $3.0 million was recorded in the first quarter
of 1998 to provide for a litigation-related cost contingency. Mariner Energy is
the defendant in litigation in the district court of Hardin County, Texas in
which the plaintiff, ETOCO, Inc., sought damages of $8.2 million plus court
costs related to the Company's operations in the Sandy Lake field. On April 22,
1998, the jury returned a verdict partially in favor of the plaintiff in the
amount of $2.4 million, before attorney's fees and interest. The Company
strongly disagrees with the jury verdict, and will vigorously contest the
verdict in the trial court and then, if necessary, in the appellate courts.
Results of the contested verdict should be known within 12 to 24 months.

    INTEREST EXPENSE increased 12% to $2.9 million for the first quarter of
1998, from $2.6 million for the first quarter of 1997 due primarily to higher
average debt.

    INCOME (LOSS) BEFORE INCOME TAXES was a $3.0 million loss for the first
quarter of 1998 primarily as a result of the provision for litigation mentioned
above. For the same period in 1997, a $27.6 million loss was reported, primarily
as a result of the impairment of oil and gas properties amounting to $28.5
million for the non-cash full cost ceiling test impairment, using prices in
effect at March 31, 1997. No impairment charge was necessary at March 31, 1998.



                                       8

<PAGE>   11




LIQUIDITY, CAPITAL EXPENDITURES AND CAPITAL RESOURCES

    At March 31, 1998, the Company had negative cash and cash equivalents of
approximately $2.2 million representing outstanding checks in excess of
short-term investments, and negative working capital of approximately $1.4
million. During the first quarter of 1998, the Company's primary source of cash
was proceeds from the revolving credit facility. The primary use of cash for the
same period was for capital expenditures associated with exploration and
development.

    The Company had a net cash outflow of $11.4 million for the first quarter of
1998, resulting from capital expenditures of $28.3 million and cash outflow from
operations of $10.1 million, offset in part by a cash inflow of $27.0 million
from the Company's revolving credit facility.

    Net cash provided by operating activities for the first quarter of 1998 was
an outflow of $10.1 million compared with a cash inflow of $7.8 million for the
same quarter of 1997. The $17.9 million decrease in cash flow was primarily due
to lower cash from changes in working capital.

    Cash flows used in investing activities in the first quarter of 1998
increased $18.1 million to $28.3 million due to higher capital expenditures
related to exploration and development, primarily on Deepwater Gulf of Mexico
exploration.

    The energy markets have historically been very volatile, and there can be no
assurance that oil and gas prices will not be subject to wide fluctuations in
the future. In an effort to reduce the effects of the volatility of the price of
oil and natural gas on the Company's operations, management has adopted a policy
of hedging oil and natural gas prices from time to time through the use of
commodity futures, options and swap agreements. While the use of these hedging
arrangements limits the downside risk of adverse price movements, it may also
limit future gains from favorable movements.

    The following table sets forth the increase (decrease) in the Company's oil
and gas sales as a result of hedging transactions and the effects of hedging
transactions on prices during the periods indicated.
<TABLE>
<CAPTION>

                                                                              Quarter Ended March 31,
                                                                            ---------------------------
                                                                               1998              1997
                                                                            ---------         ---------
<S>                                                                        <C>                <C>
 Increase (decrease) in natural gas sales (in thousands)..................  $    (56)          $(2,019)
 Increase (decrease) in oil sales (in thousands)..........................        --              (614)
 Effect of hedging transactions on average gas sales price
      (per Mcf)...........................................................     (0.01)            (0.48)
 Effect of hedging transactions on average oil sales price
      (per Bbl)...........................................................        --             (3.74)
</TABLE>

    The following table sets forth the Company's open hedging contracts for
natural gas and the weighted average prices hedged under various swap agreements
as of March 31, 1998.


                                      Hedge Quantity        Weighted
                                           Mmbtu          Average Price

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

April - October 1998..............       8,560,000          $2.33




                                       9

<PAGE>   12



    Total capital expenditures were $28.3 million for the first quarter of 1998
of which $21.1 million was spent on exploration and $7.2 million on development
activities. The Company's capital expenditures for exploratory drilling amounted
to $8.3 million for the quarter. Exploration expenditures also included partial
lease bonus payments of $10.4 million where the Company was the apparent
successful bidder on 9 Deepwater Gulf blocks at the March 18, 1998 OCS Central
Gulf of Mexico Oil and Gas Lease Sale 169. As a result of the lease sale
success, 1998 capital expenditures are expected to be $120 to $125 million.

    Debt outstanding as of March 31, 1998 was $141 million, including $100
million of subordinated senior notes and $41 million drawn on the Company's
revolving credit facility. Following the semi-annual borrowing base
redetermination, on May 4, 1998, the borrowing base under the revolving credit
facility was increased from $58 million to $60 million.

    In March 1998, Mariner Holdings, Inc., Mariner Energy's parent company,
reached an agreement in principle with its existing shareholders to contribute
approximately $28.0 million to $28.8 million of net equity capital, which is
expected to be used to reduce borrowings on the Company's revolving credit
facility and to supplement funding of the Company's 1998 capital expenditure
plan. Funding of the majority of this transaction is expected to occur in May
1998.

    The Company expects to fund its activities in 1998 through a combination of
cash flow from operations, the use of its revolving credit facility to borrow
funds required from time to time to supplement internal cash flows and by the
equity financing mentioned above. However, after including the additional equity
investment, the Company's capital resources still may not be sufficient to meet
the Company's anticipated future requirements for working capital, capital
expenditures and scheduled payments of principal and interest on its
indebtedness. There can be no assurance that anticipated growth will be
realized, that the Company's business will generate sufficient cash flow from
operations or that future borrowings or equity capital will be available in an
amount sufficient to enable the Company to service its indebtedness or make
necessary capital expenditures. In addition, depending on the levels of its cash
flow and capital expenditures (the latter of which are, to a large extent,
discretionary), the Company may need to refinance a portion of the principal
amount of its senior subordinated debt at or prior to maturity. However, there
can be no assurance that the Company would be able to obtain financing on
acceptable terms to complete a refinancing.

PART I, ITEM 3.     QUANTITATIVE AND QUALITATIVE DISCLOSURES ABOUT MARKET RISK.

    Not applicable



                                       10

<PAGE>   13



PART II.            OTHER INFORMATION


    ITEM 1.         LEGAL PROCEEDINGS

        As reported in the Company's 1997 Annual Report on Form 10-K, Mariner
Energy is the defendant in litigation in the district court of Hardin County,
Texas in which the plaintiff, ETOCO, Inc., sought damages of $8.2 million plus
court costs related to the Company's operations in the Sandy Lake field. On
April 22, 1998, the jury returned a verdict partially in favor of the plaintiff
in the amount of $2.4 million, before attorney's fees and interest. The Company
strongly disagrees with the jury verdict, and will vigorously contest the
verdict in the trial court and then, if necessary, in the appellate courts.
Results of the contested verdict should be known within 12 to 24 months.
Although no assurances can be given, the Company believes that the ultimate
outcome of the above litigation will not have a material adverse effect on the
Company's financial position.


    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

        None


    ITEM 6.         EXHIBITS AND REPORTS ON FORM 8-K

        (a) The following exhibits are filed herewith.

              27.1 Financial Data Schedule

        (b) The Company filed no Current Reports on Form 8-K during the quarter
ended March 31, 1998.








                                       11
<PAGE>   14






                                                      SIGNATURES



    Pursuant to the requirements of the Securities Exchange Act of 1934, the
registrant has duly caused this report to be signed on its behalf by the
undersigned thereunto duly authorized.


                                               MARINER ENERGY, INC.



Date: May 13, 1998                             /s/ Frank A. Pici
                                               -----------------
                                               Frank A. Pici
                                               Vice President of Finance and
                                               Chief Financial Officer
                                               (Principal Financial Officer and
                                               Officer Duly Authorized to Sign
                                               on Behalf of the Registrant)


                                       12

<PAGE>   15


                               INDEX TO EXHIBITS


                        27.1 -- Financial Data Schedule