<PAGE>   1
 
================================================================================
 
                                   FORM 10-K
 
                       SECURITIES AND EXCHANGE COMMISSION
                             Washington, D.C. 20549
 
<TABLE>
<C>   <S>
[X]   FOR THE FISCAL YEAR ENDED JUNE 30, 1997
                                   OR
[ ]   FOR THE TRANSITION PERIOD FROM                   TO                      .
                                     -----------------    ---------------------
COMMISSION FILE NO. 0-8565
</TABLE>
 
                             MARINE PETROLEUM TRUST
             (Exact name of registrant as specified in its charter)
 
<TABLE>
<C>                                            <C>
                    TEXAS                                        75-6008017
       (State or other jurisdiction of                        (I.R.S. Employer
        incorporation or organization)                      Identification No.)
</TABLE>
 
                           C/O THE CORPORATE TRUSTEE:
                           NATIONSBANK OF TEXAS, N.A.
                   P.O. BOX 830241, DALLAS, TEXAS 75283-0241
              (Address of principal executive offices) (Zip Code)
 
               Registrant's telephone number, including area code
            (at the office of the Corporate Trustee): (800) 985-0794
 
          Securities registered pursuant to Section 12(b) of the Act:
 
                                      NONE
 
          Securities registered pursuant to Section 12(g) of the Act:
 
                          UNITS OF BENEFICIAL INTEREST
 
     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, and (2) has been subject to such filing
requirements for the past 90 days.
 
                                YES  X    NO
                                    ---      ---

     Indicate by check mark if disclosure of delinquent filers pursuant to Item
405 of Regulation S-K is not contained herein, and will not be contained, to the
best of registrant's knowledge, in definitive proxy or information statements
incorporated by reference in Part III of this Form 10-K or any amendment to this
Form 10-K.  [X]
 
     Aggregate market value of Units of Beneficial Interest held by
non-affiliates of the registrant at September 5, 1997: $33,304,544.
 
     Number of Units of Beneficial Interest outstanding as of the close of the
period covered by this report: June 30, 1996 -- 2,000,000 Units.
 
                      Documents Incorporated by Reference:
 
                                      NONE
 
================================================================================
<PAGE>   2
 
                             CROSS-REFERENCE SHEET
 
     This Form 10-K for the year ended June 30, 1997 of Marine Petroleum Trust
is not organized by conventional item numbers and headings contemplated by SEC
rules and forms. This cross-reference page is intended to indicate to the reader
where (or under which headings) information required under Form 10-K may be
found herein.
 
<TABLE>
<CAPTION>
                         FORM 10-K                                           HEADINGS
                        ITEM NUMBERS                                          HEREIN
                        ------------                                         --------
<S>         <C>                                               <C>
PART I......................................................  General
  Item  1.  Business........................................  The Trust; Properties
  Item  2.  Properties......................................  Properties
  Item  3.  Legal Proceedings...............................  Legal Matters
  Item  4.  Submission of Matters to a Vote of Security
              Holders.......................................  Unitholder Voting Matters
PART II.....................................................  Financial
  Item  5.  Market for Registrant's Common Equity and
              Related Stockholder Matters...................  Market and Investor Information
  Item  6.  Selected Financial Data.........................  Selected Financial Data
  Item  7.  Management's Discussion and Analysis of
              Financial Condition and Results of
              Operations....................................  Management's Discussion and Analysis of
                                                                Financial Condition and Results of
                                                                Operations
  Item  8.  Financial Statements and Supplementary Data.....  Financial Statements and Supplementary
                                                                Data
  Item  9.  Disagreements on Accounting and Financial
              Disclosure....................................  Accounting Matters
PART III....................................................  Management and Principal Unitholders
  Item 10.  Directors and Executive Officers of the
              Registrant....................................  Administrators
  Item 11.  Management Remuneration.........................  Administrators; Management Compensation
  Item 12.  Security Ownership of Certain Beneficial Owners
              and Management................................  Principal Unitholders
  Item 13.  Certain Relationships and Related
              Transactions..................................  Administrators; Management Compensation
PART IV.....................................................  Miscellaneous
  Item 14.  Exhibits, Financial Statement Schedules and
              Reports on Form 8-K...........................  Exhibits, Financial Statement Schedules
                                                                and Reports on Form 8-K
</TABLE>
<PAGE>   3
 
                                    GENERAL
 
                                   THE TRUST
 
     Organization. Marine Petroleum Trust ("Marine") is a royalty trust created
in 1956 under the laws of the State of Texas. Marine is not permitted to engage
in any business activity inasmuch as it was organized for the sole purpose of
providing an efficient, orderly, and practical means for the administration and
liquidation of rights to payments from certain oil and gas leases in the Gulf of
Mexico, pursuant to license agreements and amendments thereto between Marine's
predecessors and Gulf Oil Corporation ("Gulf"). As a result of various
transactions that have occurred since 1956, the Gulf interests now are held by
Chevron Corporation ("Chevron"), Elf Acquitane, Inc. ("Elf"), and their
assignees.
 
     The indenture pursuant to which Marine was created (the "Indenture"),
provides that the corporate trustee is to distribute all cash in Marine, less an
amount reserved for the payment of accrued liabilities and estimated future
expenses, to unitholders of record on the last business day of September,
December, March and June of each fiscal year.
 
     The Indenture also provides that the term of the royalty trust created
thereby will expire on June 1, 2001 unless extended by the vote of the holders
of a majority of the outstanding units of beneficial interest. See "Unitholder
Voting Matters."
 
     Marine's wholly-owned subsidiary, Marine Petroleum Corporation ("MPC"),
holds title to interests in properties subject to Marine's interests that are
situated offshore of Louisiana. Ninety-eight percent of all oil, gas, and other
mineral royalties collected by this subsidiary are paid to Marine. MPC, like
Marine, is prohibited from engaging in a trade or business and does only those
things necessary for the administration and liquidation of its properties.
 
     Marine's only industry segment or purpose is the administration and
collection of royalties.
 
     Royalties. Marine's rights are generally referred to as overriding royalty
interests in the oil and gas industry, and are sometimes referred to herein as
such. All production and marketing functions are conducted by the working
interest owners of the leases. Revenues from the overriding royalties are paid
to Marine either (i) on the basis of the selling price of oil, gas and other
minerals produced, saved and sold, or (ii) at the wellhead price determined by
industry standards, when the selling price does not reflect the wellhead price.
 
     The contracts creating these interests were entered into between
predecessors of Marine and Gulf, and relate to two different types of interests.
One type of interest is an overriding royalty interest equal to three-fourths of
1% of the value at the well of any oil, gas, or other minerals produced and
sold. Marine's overriding royalty interest applies only to existing leases and
does not apply to new leases. The second interest is Marine's 32.6% equity
interest in Tidelands Royalty Trust "B" ("Tidelands"), a separate Texas trust,
which owns similar interests in any oil, gas, or other mineral lease acquired by
Gulf and/or its transferees and assignees in a 1,370,000-acre area (divided into
60 tracts) of the Gulf of Mexico during a 50-year period ending April 30, 2001.
Tidelands' interest in each tract consists of (i) a production payment, which
reverts to an overriding royalty, on oil and gas and (ii) an overriding royalty
on other minerals. The production payment is payable out of approximately 12.5%
of the value of oil and gas produced and sold from leases on a subject tract
until Tidelands has earned $1,500,000 on such tract. The production payment then
reverts to an overriding royalty interest equal to approximately 4.17% of the
value at the well of oil and gas sold from the tract. Tidelands' overriding
royalty interest on minerals other than oil and gas is payable at the rate of
4.17% of the value of such minerals sold from the property. Marine, through its
ownership of units of beneficial interest in Tidelands, derives a 32.6% interest
in the production payments and overriding royalties of Tidelands.
 
     Presently, the leases subject to Marine's interests cover 297,436 gross
acres (including Tidelands' interest in 36,485 leased acres). These leases will
remain in force until the expiration of their respective terms. Leases may be
voluntarily released by the working interest owner after all oil and gas
reserves are produced. They may also be abandoned by the working interest owner
due to failure to discover sufficient reserves to make development economically
worthwhile. In addition, the federal government may force termination if the
working interest owner fails to fully develop a lease once it is acquired.
<PAGE>   4
 
     For the year ended June 30, 1997, approximately 40% of Marine's production
payment and royalty revenues were attributable to the sale of oil and
approximately 60% were attributable to the sale of natural gas. The production
payments and royalty revenues received by Marine in respect of natural gas
production are affected by seasonal fluctuations in demand for natural gas.
Royalty revenue received by Marine from Chevron and from Pennzoil Exploration
and Production Company ("Pennzoil") accounted in the aggregate for approximately
81%, 88% and 83% of Marine's royalty revenue for the years ended June 30, 1997,
1996 and 1995, respectively. In addition, Marine's revenue from its equity
interest in Tidelands accounted for approximately 8%, 12% and 15% of Marine's
revenue for the years ended June 30, 1997, 1996 and 1995, respectively.
Tidelands has reported that royalty revenues from Chevron and Pennzoil accounted
for a substantial portion of Tidelands' royalty revenue for the years ended
December 31, 1996, 1995 and 1994.
 
     Marine derives no revenues from foreign sources and has no export sales.
 
     Trust Functions. Marine is administered by officers and employees of its
Trustee, NationsBank of Texas, N.A. MPC employs one individual (its vice
president, secretary, treasurer and as a director) to perform certain
management, financial and administrative services for Marine. Except for this
individual, all officers and directors of MPC serve without compensation. See
"Management and Principal Unitholders."
 
     MPC leases office space in Dallas, Texas to provide work space and record
storage for Marine, MPC, Tidelands and Tidelands' wholly-owned subsidiary
corporation, Tidelands Royalty "B" Corporation. The cost of this office facility
is shared by all four of these entities in proportion to each entity's gross
income to the total of such income of all entities.
 
     The ability of Marine to receive revenues is entirely dependent upon its
entitlement to its rights with respect to the leases held by Chevron and its
assignees in the Gulf of Mexico (as more fully described in "Properties" below).
Moreover, no revenues are payable to Marine until sales of production commence
from any such lease.
 
     The royalty interests held by Marine are depleting with each barrel of oil
and mcf of natural gas produced. No funds are reinvested by Marine; thus, these
depleting assets are not being replaced.
 
                                   PROPERTIES
 
     General. Marine is not engaged in oil and gas operations, although its
income is based upon such operations of others. Marine's income is derived from
contracts that provide for payments in the nature of overriding royalties to be
made to Marine based on oil and gas sales from certain leases in the Gulf of
Mexico.
 
     Reserves. Marine is not engaged in the production of crude oil or natural
gas. Its income is derived from overriding royalty payments which are carved out
of working interests in oil and gas leases in the Gulf of Mexico. Marine does
not have the engineering data necessary to make an estimate of proved oil and
gas reserves (nor the present value of future net cash flows from such
reserves), and is not entitled to receive such data from the owners of the
working interests from which Marine's interest is derived. See also "Difficulty
in Obtaining Certain Data" below.
 
     Since Marine does not have access to this reserve information, Marine is
unable to compute the standardized measure of discounted future net cash flows
therefrom.
 
     Marine did not file any reports during the fiscal year ended June 30, 1997
with any federal authority or agency with respect to oil and gas reserves.
 
                                        2
<PAGE>   5
 
     Production. Information regarding the net quantities of oil and gas
produced with respect to Marine's interests (including its equity in Tidelands)
for each of the last three fiscal years as well as the average sales price per
unit of oil and gas produced, upon which payments to Marine are based, is set
forth in the following table:
 
<TABLE>
<CAPTION>
                                                           YEAR ENDED JUNE 30,
                                                     -------------------------------
                                                      1997       1996        1995
                                                     ------    --------    ---------
<S>                                                  <C>       <C>         <C>
Quantity
  Oil (in barrels ("bbls"))........................  74,556      79,536       59,740
  Gas (in thousand cubic feet ("mcf"))............. 997,454     876,055      761,247
Average Price
  Oil (per bbl.)...................................  $21.31      $17.76       $16.36
  Gas (per mcf)....................................   $2.39       $2.08        $1.58
</TABLE>
 
     Information about average production cost (lifting cost) per unit of
production has been omitted due to its unavailability and inapplicability to
Marine. For more recent information regarding crude oil sales prices, see
"Management's Discussion and Analysis of Financial Condition and Results of
Operations" below.
 
     Productive Wells. Based on the latest information available to Marine and
including its equity interest in Tidelands, there were approximately 299 wells
subject to Marine's interests actually producing at some time in calendar 1996,
some of which contained multiple completions. During calendar 1996,
approximately 144 wells produced oil and approximately 155 wells produced gas.
Most of the oil wells also produced associated gas and most of the gas wells
produced condensate, which is economically the equivalent of oil. See
"Difficulty in Obtaining Certain Data" below.
 
     Drilling Activity. Information concerning wells drilled and completed in
which Marine had an interest (including its equity interest in Tidelands) for
each of its last three fiscal years is set forth below:
 
                                WELLS COMPLETED
 
<TABLE>
<CAPTION>
                                                              YEAR ENDED JUNE 30,
                                                              --------------------
                                                              1997    1996    1995
                                                              ----    ----    ----
<S>                                                           <C>     <C>     <C>
Development
  Oil.......................................................    1       2       3
  Gas.......................................................    6       5       9
  Suspended*................................................   18      18      14
  Dry.......................................................    4       3       3
                                                               --      --      --
       Totals...............................................   29      28      29
                                                               ==      ==      ==
</TABLE>
 
---------------
 
* "Suspended" wells are completed wells the classification of which had not been
  reported at the relevant date.
 
     Information regarding net wells or acres is not included since Marine does
not own any working interests.
 
     Lease Acreage. Marine has an overriding royalty interest (including by
virtue of its equity interest in Tidelands) in 79 different oil and gas leases
covering 297,436 gross acres. These leases are located in the Central and
Western areas of the Gulf of Mexico off the coasts of Louisiana and Texas. This
acreage has been classified according to its current stage of development and is
presented in the following table:
 
<TABLE>
<CAPTION>
                                                            ACREAGE CLASSIFICATION
                                                 ---------------------------------------------
              LEASES GRANTED BY:                 PRODUCING   DEVELOPMENTAL(1)   EXPLORATORY(2)
              ------------------                 ---------   ----------------   --------------
<S>                                              <C>         <C>                <C>
United States..................................   283,675            0              8,231
State of Texas.................................       640            0                  0
State of Louisiana.............................     4,890            0                  0
                                                  -------           --              -----
                                                  289,205            0              8,231
                                                  =======           ==              =====
</TABLE>
 
                                        3
<PAGE>   6
 
---------------
 
(1) By definition, "Developmental Acreage" may be expected to produce royalty
    income at some point in the future.
 
(2) Leases are typically granted for a term of five years, during which the
    lease owner must establish a commercial production capability, or the lease
    expires. No commercial production has been established on the acreage
    classified above by Marine under the column heading "Exploratory." By
    definition, this acreage includes undrilled wildcat acreage as well as some
    possible discoveries which are awaiting further testing. The 8,231 acres are
    located on leases that have commercial production, but the production is not
    on Marine's overriding royalty area within those leases.
 
The overriding royalty interest owned by Marine is a fractional interest out of
total oil and gas sold, and is free and clear of all operating costs. The actual
percentage interest in a lease attributable to Marine's interest varies from
lease to lease. The acreage weighted average percentage interest attributable to
Marine's interest in all of these leases is .5869%.
 
     Present Activities. Published reports indicate that 10 wells are being
drilled on tracts in which Marine has an interest. Marine understands that
drilling on 5 of these wells has been completed, but Marine has no information
regarding the prospects of future production from these wells. Marine also
understands from published reports that plans are being made to begin drilling
on 2 additional wells.
 
     The U.S. Department of the Interior conducted a lease sale for the Gulf of
Mexico in April and August, 1997. Chevron did not bid on any tracts included in
this sale that are located in the 1,370,000 acre area subject to the Tidelands
contract (in which Marine has a 32.6% equity interest.)
 
     Difficulty in Obtaining Certain Data. Marine's only activities are the
collection and distribution of revenues from overriding royalties on certain oil
and gas leases in the Gulf of Mexico, pursuant to purchase agreements between
Marine's predecessors and Gulf and its transferees. The leasehold working
interests which are subject to the rights held by Marine are owned, in most
cases, in whole or in part by Chevron, or other oil and gas exploration and
production companies. Certain information as to reserves, availability of oil
and gas, average production cost (lifting cost) per unit, undeveloped acreage,
net wells and net acres, etc., with respect to the particular leases subject to
Marine's interests lies solely within the knowledge of these concerns.
Engineering data, if any, regarding these leaseholds would have been compiled
principally by or for the working interest owners of these leaseholds and Marine
believes that it will not be provided access to such information. Because of
this, it appears that unreasonable efforts and expense would be involved in
seeking to obtain all of the information required under Item 102 of Regulation
S-K and Securities Exchange Act of 1934 Industry Guide 2.
 
                                 LEGAL MATTERS
 
     Neither Marine nor MPC, nor any of their respective properties (exclusive
of properties owned by Chevron and subject to the Marine and Tidelands license
agreements), is a party to or subject to any material pending litigation as of
the date hereof.
 
                           UNITHOLDER VOTING MATTERS
 
     No matter was submitted by Marine during the year ended June 30, 1997 to a
vote of unitholders, whether through the solicitation of proxies or otherwise.
 
     Unitholders owning ten percent (10%) or more of the outstanding units may
at any time direct the Trustee to conduct an investigation to determine whether
the Trustee is receiving all revenues properly accruing to Marine's trust
estate. The Trustee may be removed by unitholders owning a majority of the
outstanding units. The unitholders owning eighty percent (80%) of the
outstanding units may amend and modify the Trust Indenture or any contract,
agreement or undertaking which constitutes a part of the trust estate, but no
such amendment may change the nature of the trust from that of a purely
ministerial trust, nor can there be any change in the rights or responsibilities
of the Trustee without its consent. However, no such
 
                                        4
<PAGE>   7
 
change shall be made with respect to any amendment to the Indenture if the
Trustee shall receive written objection from any unitholder within 20 days from
the date of mailing to the unitholders of the first notice of the proposed
consent. Each unitholder has the right to examine, inspect and audit all records
relating to the trust estate.
 
     Marine is to continue until June 1, 2001, or until such later date as
holders of the units owning a majority of the outstanding units may designate,
but in any event, not more than 20 years from such designation. Alternatively,
instead of so extending the term of Marine, the holders of the units owning a
majority of the outstanding units may direct the Trustee to create one or more
corporations to receive and hold the trust estate, or any portion thereof,
unless the Trustee shall have received written objection from any unitholder
within 20 days from the date of mailing to the unitholders of the first notice
of the proposed consent. However, the unitholders owning eighty percent (80%) of
the outstanding units may terminate the trust on any date, whether earlier or
later than any such date determined as above, as they may specify.
 
     Upon termination of the trust (other than by the transfer of all the trust
estate to a corporation pursuant to the provisions of the Indenture, as
described above), the Trustee, after paying all of the obligations of the trust,
shall transfer to an agent appointed by the holders of the units owning a
majority of the outstanding units, by recordable assignments but without
warranty, the interests in the trust estate. Prior to termination of the trust,
no unitholder shall have any legal title in or to any of the properties
comprising the trust estate nor the right to secure any partition thereof.
 
                                   FINANCIAL
 
                        MARKET AND INVESTOR INFORMATION
 
     The units of beneficial interest in Marine are traded in the
over-the-counter market, and are quoted on the NASDAQ system under the symbol
MARPS. Distributions of cash are made to unitholders quarterly. The following
table presents the range of high and low bid and asked prices by quarter for the
past two years as reported by the National Quotation Bureau, Incorporated. The
per unit amount of cash distributed to unitholders for each of these quarters is
also presented in the table.
 
<TABLE>
<CAPTION>
                                           BID                ASKED
                                     ----------------    ----------------    DISTRIBUTIONS
          QUARTER ENDING              HIGH      LOW       HIGH      LOW        PER UNIT
          --------------             ------    ------    ------    ------    -------------
<S>                                  <C>       <C>       <C>       <C>       <C>
September 30, 1995.................   11.50     10.50     12.75     11.75         .274
December 31, 1995..................   10.25     10.25     11.75     11.00         .290
March 31, 1996.....................   10.50     10.00     11.75     11.25         .307
June 30, 1996......................   10.50     10.00     11.75     11.25         .402
September 30, 1996.................   12.75     10.00     14.25     11.50         .496
December 31, 1996..................   14.75     12.75     16.00     14.25         .490
March 31, 1997.....................   16.00     14.75     17.50     16.00         .520
June 30, 1997......................   16.00     13.75     17.25     15.25         .464
</TABLE>
 
     These over-the-counter market quotations only represent interdealer prices
without retail mark-up, mark-down or commission and may not necessarily
represent actual transactions. Marine is authorized to issue and has issued
2,000,000 units of beneficial interest. On August 29, 1997, these outstanding
units were held of record by 818 unitholders.
 
                                        5
<PAGE>   8
 
                            SELECTED FINANCIAL DATA
 
<TABLE>
<CAPTION>
                                                    (IN THOUSANDS EXCEPT PER UNIT AMOUNTS)
                                                ----------------------------------------------
                                                 1997      1996      1995      1994      1993
                                                ------    ------    ------    ------    ------
<S>                                             <C>       <C>       <C>       <C>       <C>
STATEMENT OF INCOME AND UNDISTRIBUTED INCOME
  SELECTED DATA
  Income:
     Oil and gas royalties....................  $3,645    $2,842    $1,857    $2,044    $1,864
     Equity in Tidelands......................     319       385       320     1,156       627
     Interest.................................     101        92        83        51        61
                                                ------    ------    ------    ------    ------
                                                $4,065    $3,319    $2,260    $3,251    $2,552
                                                ------    ------    ------    ------    ------
  Expenses:
     Taxes other than income..................  $    0    $    0    $    0    $    1    $    1
     General and administrative...............     143       121       118       106       135
     Federal income taxes.....................       8        12         6         3         1
                                                ------    ------    ------    ------    ------
                                                $  151    $  133    $  124    $  110    $  137
                                                ------    ------    ------    ------    ------
     Net income...............................  $3,914    $3,186    $2,136    $3,141    $2,415
                                                ======    ======    ======    ======    ======
     Distributions............................  $3,939    $2,548    $2,287    $3,329    $2,308
                                                ======    ======    ======    ======    ======
  Per Unit (2,000,000 outstanding)
     Net income...............................  $ 1.96    $ 1.59    $ 1.07    $ 1.57    $ 1.21
                                                ======    ======    ======    ======    ======
     Distributions............................  $ 1.97    $ 1.27    $ 1.14    $ 1.66    $ 1.15
                                                ======    ======    ======    ======    ======
BALANCE SHEET SELECTED DATA
  Total assets................................  $2,945    $2,979    $2,338    $2,489    $2,669
                                                ======    ======    ======    ======    ======
  Trust equity................................  $2,045    $2,070    $1,432    $1,583    $1,771
                                                ======    ======    ======    ======    ======
</TABLE>
 
                                        6
<PAGE>   9
 
                    MANAGEMENT'S DISCUSSION AND ANALYSIS OF
                 FINANCIAL CONDITION AND RESULTS OF OPERATIONS
 
     Capital Resources and Liquidity. Because of the nature of Marine as a trust
entity, there is no requirement for capital; its only obligation is to
distribute to unitholders the net income actually collected. As an administrator
of oil and gas royalty properties, Marine collects income monthly, pays expenses
of administration, and disburses all net income collected to its unitholders
each quarter.
 
     Marine's Indenture (and the charter and by-laws of MPC) expressly prohibits
the operation of any kind of trade or business. Marine's oil and gas properties
are depleting assets and are not being replaced due to the prohibition against
these investments. These restrictions, along with other factors, allow Marine to
be treated as a grantor trust; thus all income and deductions, for tax purposes,
should flow through to each individual unitholder. Marine is not a taxable
entity.
 
     Results of Operations. Marine's income consists primarily of oil and gas
royalties and is based on the value at the well of its percentage interest in
oil and gas sold without reduction for any of the expense of production. Value
at the well for oil is the purchasers' posted price at its receiving point
onshore, less the cost of transportation from the offshore lease to the onshore
receiving point. In general, value at the well is determined on the basis of the
selling price of oil, gas and other minerals produced, saved and sold, or at
wellhead prices determined by industry standards, where the selling price does
not reflect value at the well.
 
     Summary Review. Marine's net income for the year ended June 30, 1997
amounted to $3,914,197 ($1.96 per unit) as compared to $3,185,852 ($1.59 per
unit) in the previous year. This 23% increase is due to increased gas production
and increased prices for both oil and gas. During the past 5 years the working
interest owners have drilled and completed 114 new wells on leases in which
Marine has an interest and these new wells are largely responsible for the
increased production. Most (93% or 106) of the wells drilled in the past five
years were located on leases in the Louisiana offshore area. Approximately 95%
of Marine's income for the year ended June 30, 1997 is from wells located
offshore Louisiana.
 
     An analysis of well production records for calendar 1996 (for wells on
leases in which Marine has an interest) shows that 28% of gas production and 19%
of oil production for that year was from wells completed in 1996. The analysis
also shows that 65% of gas production and 79% of oil production for 1996 was
from wells completed during the past 5 years.
 
     Income from Marine's equity interest in Tidelands amounted to $319,251 in
the current fiscal year and in the previous year it was $384,753. Income from
Tidelands contributed 8% of Marine's net income for the current year.
 
     During the current year the working interest owners on leases in which
Marine has an interest have commenced the drilling or redrilling of 29 wells, 7
of which were classified as either oil or gas wells, 18 of which were not
classified (but appeared to be capable of producing either oil or gas) and 4 of
which were not successful. Burlington Resources has drilled three new gas wells
on Galveston Block 303. Tidelands has a 4.17% overriding royalty interest in
these wells. As of June 30, 1997 only one of the wells was producing. Marine
understands that the other two wells went on stream after June 30, 1997.
 
     The increases in revenue and net income this past year are primarily the
result of increased prices for oil and gas. Natural gas prices increased $.31
per mcf and that increase combined with the 121,399 mcf increase in the quantity
of natural gas sold contributed an additional $.28 per unit of beneficial
interest to Marine's net income for the year. Likewise, the $3.55 per barrel
increase in the price of oil, after the effect of the 4,980 barrel reduction in
the quantity of oil sold, contributed to net income an additional $.09 per unit
of beneficial interest.
 
     The production weighted average oil price rose dramatically during the
second fiscal quarter reaching $28.98 per barrel but ended the year at the level
started, $20.08. The production weighted average gas price remained fairly
constant during the year, rising slightly during the second and third fiscal
quarters.
 
     It is anticipated that oil prices will be down slightly during the quarter
ending September 30, 1997. However, gas prices on the futures market and spot
prices on the Louisiana Coast are showing strength and it is anticipated that
such prices will be up slightly in the September 1997 quarter.
 
                                        7
<PAGE>   10
 
     The following table shows the royalty income, the net quantities sold, and
the average price received for oil and gas during the past three years
(including Marine's equity interest in Tidelands):
 
<TABLE>
<CAPTION>
                                                         FOR YEARS ENDED JUNE 30
                                                   ------------------------------------
                                                      1997         1996         1995
                                                   ----------   ----------   ----------
<S>                                                <C>          <C>          <C>
Income from
  Oil royalties..................................  $1,588,476   $1,412,750   $  977,246
  Gas royalties..................................   2,379,437    1,819,807    1,199,192
                                                   ----------   ----------   ----------
          Totals.................................  $3,967,913   $3,232,557   $2,176,438
                                                   ----------   ----------   ----------
Net quantities sold
  Oil (bbls).....................................      74,556       79,536       59,740
  Gas (mcf)......................................     997,454      876,055      761,247
Average price
  Oil............................................      $21.31       $17.76       $16.36
  Gas............................................        2.39         2.08         1.58
</TABLE>
 
     Marine's revenues are derived from the oil and gas production activities of
unrelated parties. Marine's revenues and distributions fluctuate from period to
period based upon factors beyond Marine's control, including without limitation
the number of leases bid on and obtained by parties subject to Marine's
interests, the number of productive wells drilled on leases subject to Marine's
interests, the level of production over time from such wells and the prices at
which the oil and gas from such wells is sold. Marine believes that it will
continue to have revenues sufficient to permit distributions to be made to
unitholders for the foreseeable future, although no assurance can be made
regarding the amounts thereof. The foregoing sentence is a forward-looking
statement. Factors that might cause actual results to differ from expected
results include reductions in prices or demand for oil and gas, which might then
lead to decreased production; reductions in production due to depletion of
existing wells or disruptions in service, including as the result of storm
damage, blowouts or other production accidents, and geological changes such as
cratering of productive formations; expiration or release of leases subject to
Marine's interests; and the discontinuation by parties subject to Marine's
interests of their efforts to obtain leases in the Royalty Area.
 
     Oil and Gas Royalties -- 1996 and 1997: During fiscal 1997, Marine
received, exclusive of its interest in Tidelands, 42% of its royalty income from
the sale of oil and 58% from the sale of natural gas. Income from such oil and
gas royalties in fiscal 1997 increased 28% from fiscal 1996.
 
     Oil royalties, exclusive of Marine's interest in Tidelands, during fiscal
1997 ($1,544,131) were 12% more than oil royalties received in fiscal 1996
($1,375,880).
 
     Natural gas royalties, exclusive of Marine's interest in Tidelands, during
fiscal 1997 ($2,100,873) were 43% more than natural gas royalties received in
fiscal 1996 ($1,465,668).
 
     Interest Income -- 1996 and 1997. Marine's interest income increased 9%
during fiscal 1997 to $100,705 from the $92,275 earned in fiscal 1996, due
primarily to an increase in invested funds held for distribution.
 
     Equity in Tidelands -- 1996 and 1997. Marine owns beneficially 32.6% of the
outstanding units of beneficial interest in Tidelands. In fiscal 1997, Marine
realized income of $319,251 from its interest in Tidelands, a decrease of 17%
from the $384,753 earned in fiscal 1996. See "-- Summary Review" above.
 
     Pursuant to Tidelands' agreement with Chevron (as successor to Gulf's
interests), should Chevron acquire a lease or leases on any specified tracts in
the Gulf of Mexico before April 30, 2001, and oil or gas is produced or sold,
Chevron will make production payments to Tidelands in an amount equal to 12.5%
of the value of the oil and gas sold until the sum of $1,500,000 has been paid
on the tract. Thereafter, Tidelands' interest will be converted to an overriding
royalty and such payments will equal 4.17% of the value of the oil and gas sold
as long as the lease exists.
 
     Oil and Gas Royalties  -- 1995 and 1996: During fiscal 1996, Marine
received approximately 43% of its royalty income from the sale of oil and 56%
from the sale of natural gas. Income from such oil and gas royalties in fiscal
1996 increased approximately 49% from fiscal 1995.
 
                                        8
<PAGE>   11
 
     Oil royalties, exclusive of Marine's interest in Tidelands, during fiscal
1996 ($1,375,880) were 45% more than oil royalties received in fiscal 1995
($946,009), due to an increase in the quantity of oil sold and an increase in
the average price received for oil sold.
 
     Natural gas royalties, exclusive of Marine's interest in Tidelands, during
fiscal 1996 ($1,465,669) were 61% higher than natural gas royalties received in
fiscal 1995 ($910,496). The increase was due to an increase in the quantity of
natural gas sold and an increase in the price received.
 
     Interest Income -- 1995 and 1996. Marine's interest income during fiscal
1996 increased 11% to $92,275 from the $82,927 earned in fiscal 1995, due
primarily to higher interest rates.
 
     Equity in Tidelands -- 1995 and 1996. Marine realized income of $384,753
during fiscal 1996 from its interest in Tidelands, an increase of 20% from the
$320,082 earned in fiscal 1995.
 
                  FINANCIAL STATEMENTS AND SUPPLEMENTARY DATA
 
     The financial statements listed in the following Index, together with the
related notes and the report of KPMG Peat Marwick LLP, independent certified
public accountants, are presented on pages 11 through 18 hereof.
 
<TABLE>
<CAPTION>
                                                              PAGE
                                                              ----
<S>                                                           <C>
Independent Auditors' Report................................   11
Financial Statements:
  Consolidated Balance Sheets as of June 30, 1997 and
     1996...................................................   12
  Consolidated Statements of Income and Undistributed Income
     for the Three Years Ended June 30, 1997................   13
  Consolidated Statements of Cash Flows for
     the Three Years Ended June 30, 1997....................   14
  Notes to Consolidated Financial Statements................   15
</TABLE>
 
     See also "Exhibits, Financial Statement Schedules and Reports on Form 8-K"
of this Form 10-K for further information concerning the financial statements of
Marine and its subsidiaries.
 
     All schedules have been omitted for the reason that they are either not
required, not applicable or the required information is included in the
financial statements and notes thereto.
 
                               ACCOUNTING MATTERS
 
     During fiscal 1997 and 1996, there have been no disagreements between
Marine and its independent auditors on accounting or financial disclosure
matters which would warrant disclosure under Item 304 of Regulation S-K.
 
                      MANAGEMENT AND PRINCIPAL UNITHOLDERS
 
                                 ADMINISTRATORS
 
     Marine is a trust created under the laws of the State of Texas. Marine's
Indenture does not provide for directors or officers or the election of
directors or officers. Under the Indenture, NationsBank of Texas, N.A., serves
as Trustee.
 
     R. Ray Bell may be considered a significant employee of Marine. Mr. Bell
has been involved in the administration of Marine since its inception. He was
the chief financial officer of Marine's predecessor and is a certified public
accountant. Mr. Bell, 70 years old, is a graduate of Midwestern State University
of Wichita Falls, Texas with a Bachelor of Science degree in business
administration and economics. Since July 1, 1977, he has served as vice
president and director of MPC, and will continue to serve in such capacities
until the next meeting of directors and shareholders, respectively, of MPC or
until his successors are elected and qualified.
 
                                        9
<PAGE>   12
 
                            MANAGEMENT COMPENSATION
 
     During the fiscal year ended June 30, 1997, Marine paid or accrued fees of
$14,126 to NationsBank of Texas, N.A., as Trustee. These fees were paid in
accordance with the terms of the Trust Indenture, as amended, governing Marine.
 
                             PRINCIPAL UNITHOLDERS
 
     The following table sets forth the persons known to Marine who own
beneficially more than five percent of the outstanding units of beneficial
interest as of June 30, 1997:
 
<TABLE>
<CAPTION>
                                          AMOUNT AND NATURE OF   PERCENT
  TITLE OF CLASS      NAME AND ADDRESS    BENEFICIAL OWNERSHIP   OF CLASS
  --------------      ----------------    --------------------   --------
<S>                  <C>                  <C>                    <C>
Units of Beneficial  L. C. Paslay          286,469 units,          14.32%
  Interest           1020 S. Ocean Blvd.   owned
                     Manalapan, FL 33462   of record
                                           and beneficially*
</TABLE>
 
---------------
 
* Does not include 27,225 units held in trust in the name of L. C. Paslay, as
  Co-Trustee with NationsBank of Texas, N.A., for the benefit of Patricia L.
  Martin, daughter of Mr. Paslay.
 
     There are no executive officers or directors of Marine. NationsBank of
Texas, N.A. does not beneficially own any units of beneficial interest.
 
                                 MISCELLANEOUS
 
        EXHIBITS, FINANCIAL STATEMENT SCHEDULES AND REPORTS ON FORM 8-K
 
     (a) Financial Statements -- see "Financial Statements and Supplementary
Data" above.
 
     The consolidated financial statements, together with the related notes and
the report of KPMG Peat Marwick LLP, independent certified public accountants,
as contained in the Form 10-K of Tidelands Royalty Trust "B" for its fiscal year
ended December 31, 1996 and filed with the Securities and Exchange Commission,
are hereby incorporated herein by reference for all purposes.
 
     (b) Reports on Form 8-K -- No reports on Form 8-K have been filed during
the last quarter of the fiscal year ended June 30, 1997.
 
     (c) Exhibits:
 
<TABLE>
<S>                   <C>
          (3)         -- Indenture, as amended, of Marine, filed as Exhibit 3 to the Annual Report on Form
                         10-K of Marine Petroleum Trust for the fiscal year ended June 30, 1994, filed with
                         the Securities and Exchange Commission and incorporated by reference herein.
          (4)         -- Form of Certificate evidencing Unit(s) of Beneficial Interest, filed as Exhibit 4 to
                         the Annual Report on Form 10-K of Marine Petroleum Trust for the fiscal year ended
                         June 30, 1994, filed with the Securities and Exchange Commission and incorporated by
                         reference herein.
          (21)        -- Subsidiaries of Marine.
          (27)        -- Financial Data Schedule.
</TABLE>
 
                                       10
<PAGE>   13
 
                          INDEPENDENT AUDITORS' REPORT
 
The Trustee
Marine Petroleum Trust:
 
     We have audited the accompanying consolidated balance sheets of Marine
Petroleum Trust and subsidiary as of June 30, 1997 and 1996 and the related
consolidated statements of income and undistributed income and cash flows for
each of the years in the three-year period ended June 30, 1997. These financial
statements are the responsibility of the Trust's management. Our responsibility
is to express an opinion on these financial statements based on our audits.
 
     We conducted our audits in accordance with generally accepted auditing
standards. Those standards require that we plan and perform the audit to obtain
reasonable assurance about whether the financial statements are free of material
misstatement. An audit includes examining, on a test basis, evidence supporting
the amounts and disclosures in the financial statements. An audit also includes
assessing the accounting principles used and significant estimates made by
management, as well as evaluating the overall financial statement presentation.
We believe that our audits provide a reasonable basis for our opinion.
 
     In our opinion, the consolidated financial statements referred to above
present fairly, in all material respects, the financial position of Marine
Petroleum Trust and subsidiary as of June 30, 1997 and 1996 and the results of
their operations and their cash flows for each of the years in the three-year
period ended June 30, 1997, in conformity with generally accepted accounting
principles.
 
                                            KPMG PEAT MARWICK LLP
 
Dallas, Texas
August 22, 1997
 
                                       11
<PAGE>   14
 
                     MARINE PETROLEUM TRUST AND SUBSIDIARY
 
                          CONSOLIDATED BALANCE SHEETS
                             JUNE 30, 1997 AND 1996
 
                                     ASSETS
 
<TABLE>
<CAPTION>
                                                                 1997            1996
                                                              ----------      ----------
<S>                                                           <C>             <C>
Current assets:
  Cash and cash equivalents.................................  $1,759,718      $2,020,695
  Oil and gas royalties receivable..........................     835,230         587,925
  Receivables from affiliate (note 2).......................      64,580         102,726
                                                              ----------      ----------
          Total current assets..............................   2,659,528       2,711,346
                                                              ----------      ----------
Investment in affiliate (note 2)............................     285,478         266,482
Office equipment, at cost less accumulated depreciation
  of $19,415 in 1997 and $18,716 in 1996....................         272             971
Producing oil and gas properties............................           7               7
                                                              ----------      ----------
                                                              $2,945,285      $2,978,806
                                                              ==========      ==========
 
                              LIABILITIES AND TRUST EQUITY
 
Current liabilities:
  Accounts payable (note 3).................................  $  895,724      $  895,724
  Employment tax payable....................................          --           2,459
  Income taxes payable......................................       4,758          10,670
                                                              ----------      ----------
     Total current liabilities..............................     900,482         908,853
                                                              ----------      ----------
Trust equity:
  Corpus -- authorized 2,000,000 units of beneficial
     interest, issued 2,000,000 units at nominal value......           8               8
  Undistributed income......................................   2,044,795       2,069,945
                                                              ----------      ----------
          Total trust equity................................   2,044,803       2,069,953
                                                              ----------      ----------
                                                              $2,945,285      $2,978,806
                                                              ==========      ==========
</TABLE>
 
          See accompanying notes to consolidated financial statements.
 
                                       12
<PAGE>   15
 
                     MARINE PETROLEUM TRUST AND SUBSIDIARY
 
           CONSOLIDATED STATEMENTS OF INCOME AND UNDISTRIBUTED INCOME
                        THREE YEARS ENDED JUNE 30, 1997
 
<TABLE>
<CAPTION>
                                                            1997          1996          1995
                                                         ----------    ----------    ----------
<S>                                                      <C>           <C>           <C>
Income:
  Oil and gas royalties................................  $3,645,004    $2,841,549    $1,856,505
  Equity in earnings of affiliate (note 2).............     319,251       384,753       320,082
  Interest income......................................     100,705        92,275        82,927
                                                         ----------    ----------    ----------
                                                          4,064,960     3,318,577     2,259,514
                                                         ----------    ----------    ----------
Expenses:
  Taxes other than income..............................         282           276           326
  General and administrative...........................     142,781       120,549       117,771
                                                         ----------    ----------    ----------
                                                            143,063       120,825       118,097
                                                         ----------    ----------    ----------
          Income before federal income taxes...........   3,921,897     3,197,752     2,141,417
Federal income taxes of subsidiary.....................       7,700        11,900         5,756
                                                         ----------    ----------    ----------
          Net income...................................   3,914,197     3,185,852     2,135,661
Undistributed income at beginning of year..............   2,069,945     1,431,862     1,583,247
                                                         ----------    ----------    ----------
                                                          5,984,142     4,617,714     3,718,908
Distributions to unitholders...........................   3,939,347     2,547,769     2,287,046
                                                         ----------    ----------    ----------
Undistributed income at end of year....................  $2,044,795    $2,069,945    $1,431,862
                                                         ==========    ==========    ==========
Net income per unit....................................  $     1.96    $     1.59    $     1.07
                                                         ==========    ==========    ==========
Distributions per unit.................................  $     1.97    $     1.27    $     1.14
                                                         ==========    ==========    ==========
</TABLE>
 
          See accompanying notes to consolidated financial statements.
 
                                       13
<PAGE>   16
 
                     MARINE PETROLEUM TRUST AND SUBSIDIARY
 
                     CONSOLIDATED STATEMENTS OF CASH FLOWS
                        THREE YEARS ENDED JUNE 30, 1997
 
<TABLE>
<CAPTION>
                                                         1997           1996           1995
                                                      -----------    -----------    -----------
<S>                                                   <C>            <C>            <C>
Cash flows from operating activities:
  Net income........................................  $ 3,914,197    $ 3,185,852    $ 2,135,661
  Adjustments to reconcile net income to net cash
     provided by operating activities:
     Depreciation...................................          699            701            771
     Equity in undistributed earnings of
       affiliate....................................      (18,996)       (67,256)            --
     Change in assets and liabilities:
       Oil and gas royalties receivable.............     (247,305)      (200,465)      (102,893)
       Receivables from affiliate...................       38,146        (13,955)        34,855
       Employment tax payable.......................       (2,459)        (1,377)         1,377
       Income taxes payable.........................       (5,912)         3,652           (994)
                                                      -----------    -----------    -----------
            Net cash provided by operating
               activities...........................    3,678,370      2,907,152      2,068,777
 
Cash flows provided by investing activities --
  distributions received in excess of earnings of
     affiliate......................................           --             --         54,074
 
Cash flows used in financing
  activities -- distributions to unitholders........   (3,939,347)    (2,547,769)    (2,287,046)
                                                      -----------    -----------    -----------
 
Net increase (decrease) in cash and cash
  equivalents.......................................     (260,977)       359,383       (164,195)
Cash and cash equivalents at beginning of year......    2,020,695      1,661,312      1,825,507
                                                      -----------    -----------    -----------
 
Cash and cash equivalents at end of year............  $ 1,759,718    $ 2,020,695    $ 1,661,312
                                                      ===========    ===========    ===========
</TABLE>
 
          See accompanying notes to consolidated financial statements.
 
                                       14
<PAGE>   17
 
                     MARINE PETROLEUM TRUST AND SUBSIDIARY
 
                   NOTES TO CONSOLIDATED FINANCIAL STATEMENTS
                        THREE YEARS ENDED JUNE 30, 1997
 
(1) SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES
 
  (a) General
 
     The Marine Petroleum Trust ("Trust") was established on June 1, 1956 with
the transfer of property to the Trust consisting of certain contract rights,
units of beneficial interest and common stock in exchange for units of
beneficial interest in the Trust. The contract rights entitled the Trust to
receive a .0075 overriding royalty interest in oil, gas and other mineral
leasehold interests acquired by Gulf Oil Corporation, now Chevron U.S.A., Inc.
("Chevron"), a subsidiary of Chevron Corporation, in certain areas of the Gulf
of Mexico prior to January 1, 1980. Substantially all royalty revenue is
received from Chevron.
 
     The Trust must distribute all income, after paying its liabilities and
obligations, to the unitholders during the months of March, June, September and
December each year. It cannot invest any of its money for any purpose and cannot
engage in a trade or business.
 
     A Louisiana trust can only exist for a short period of time; therefore, the
unitholders assigned their contract rights off-shore of Louisiana to Marine
Petroleum Corporation reserving a 98% net profits interest to themselves. The
net profits interest contract was transferred to the Trust along with the other
properties. The Trust is authorized to pay expenses of the Corporation should it
be necessary.
 
     The Trust is to continue until June 1, 2001, or until such later date as
holders of the units owning a majority of the outstanding units may designate,
but in any event, not more than 20 years from such designation. Alternatively,
instead of so extending the term of the Trust, the holders of the units owning a
majority of the outstanding units may direct the Trustee to create one or more
corporations to receive and hold the trust estate, or any portion thereof,
unless the Trustee shall have received written objection from any unitholder
within 20 days from the date of mailing to the unitholders of the first notice
of the proposed consent. However, the unitholders owning eighty percent (80%) of
the outstanding units may terminate the trust on any date.
 
  (b) Principles of Consolidation
 
     The consolidated financial statements include the Trust and its
wholly-owned subsidiary, Marine Petroleum Corporation. All material intercompany
accounts and transactions have been eliminated in consolidation.
 
  (c) Producing Oil and Gas Properties
 
     At the time the Trust was established, no determinable market value was
available for the assets transferred to the Trust; consequently, nominal values
were assigned. Because of this, no allowance for depletion has been computed.
 
     All income from oil and gas royalties relate to proved developed oil and
gas reserves.
 
  (d) Undistributed Income
 
     The Trust indenture agreement provides that all cash of the Trust, less
such amounts as become distributable at earlier record dates but not yet
distributed, and less a maximum of $2,000, shall be distributed on the 28th day
of March, June, September and December of each year to unitholders in the Trust.
Undistributed income includes $682,033 and $632,092 applicable to the subsidiary
corporation at June 30, 1997 and 1996, respectively.
 
                                       15
<PAGE>   18
 
                     MARINE PETROLEUM TRUST AND SUBSIDIARY
 
           NOTES TO CONSOLIDATED FINANCIAL STATEMENTS -- (CONTINUED)
                        THREE YEARS ENDED JUNE 30, 1997
 
  (e) Federal Income Taxes
 
     No provision has been made for Federal income taxes on the Trust's income
since such taxes are the liability of the unitholders. Federal income taxes have
been provided on the income of the subsidiary corporation, excluding the 98% net
profits interest to be distributed to the Trust and deducting statutory
depletion.
 
  (f) Credit Risk Concentration and Cash Equivalents
 
     Financial instruments which potentially subject the Trust and its
wholly-owned subsidiary to concentrations of credit risk are primarily
investments in cash equivalents and receivables. The Trust and its wholly-owned
subsidiary place their cash investments with financial institutions or companies
that management considers credit worthy and limit the amount of credit exposure
from any one financial institution or company. The Trust has not experienced
significant problems collecting its receivables in the past.
 
     The Trust and its wholly-owned subsidiary had cash equivalents of
$1,726,851 and $1,866,963 at June 30, 1997 and 1996, respectively, which
consisted of money market accounts and money market mutual funds. For purposes
of the statements of cash flows, the Trust considers all investments with
maturities of three months or less to be cash equivalents.
 
  (g) Statements of Cash Flows
 
     The Trust's wholly-owned subsidiary made Federal income tax payments of
$13,792, $8,248, and $6,750 during the years ended June 30, 1997, 1996 and 1995,
respectively.
 
  (h) Fair Value of Financial Instruments
 
     The Trust and its wholly owned subsidiary define the fair value of a
financial instrument as the amount at which the instrument could be exchanged in
a current transaction between willing parties. The carrying value of cash and
cash equivalents, oil and gas royalties receivable, receivables from affiliates,
accounts payable, and taxes payable approximate fair value because of the short
maturity of those instruments.
 
  (i) Use of Estimates
 
     Management of the Trust and its wholly-owned subsidiary has made a number
of estimates and assumptions relating to the reporting of assets and liabilities
and the disclosure of contingent assets and liabilities to prepare these
financial statements in conformity with generally accepted accounting
principles. Actual results could differ from those estimates.
 
(2) INVESTMENT IN AND RECEIVABLES FROM AFFILIATE -- TIDELANDS ROYALTY TRUST "B"
 
     At June 30, 1997 and 1996, the Trust owned 32.63% of the outstanding units
of interest in Tidelands Royalty Trust "B" ("Tidelands"). The 452,366 units
owned by the Trust had a quoted market value of $2,657,650, and $2,714,196 at
June 30, 1997 and 1996, respectively.
 
     The Trust and Tidelands share certain common costs which are allocated
based on their respective net revenues.
 
                                       16
<PAGE>   19
 
                     MARINE PETROLEUM TRUST AND SUBSIDIARY
 
           NOTES TO CONSOLIDATED FINANCIAL STATEMENTS -- (CONTINUED)
                        THREE YEARS ENDED JUNE 30, 1997
 
     The investment in affiliate is accounted for by the equity method. The
following summarizes changes in this account for 1997 and 1996:
 
<TABLE>
<CAPTION>
                                                                1997         1996
                                                              ---------    ---------
<S>                                                           <C>          <C>
Balance at beginning of year................................  $ 266,482    $ 199,226
Equity in earnings of affiliate.............................    319,251      384,753
Distribution of earnings....................................   (300,255)    (317,497)
                                                              ---------    ---------
Balance at end of year......................................  $ 285,478    $ 266,482
                                                              =========    =========
</TABLE>
 
     At June 30, 1997 and 1996, receivables from affiliate includes $57,321 and
$93,072, respectively, of income distributable to the Trust as a Tidelands
unitholder.
 
     The following summary financial statements have been compiled from the
unaudited consolidated financial statements of Tidelands.
 
                                 BALANCE SHEETS
 
                                     ASSETS
 
<TABLE>
<CAPTION>
                                                                      JUNE 30
                                                              ------------------------
                                                                 1997          1996
                                                              ----------    ----------
<S>                                                           <C>           <C>
Cash and cash equivalents...................................  $1,716,781    $1,819,636
Oil and gas royalties receivable............................     282,748       231,137
Other.......................................................       3,980         6,478
                                                              ----------    ----------
                                                              $2,003,509    $2,057,251
                                                              ==========    ==========
</TABLE>
 
                          LIABILITIES AND TRUST EQUITY
 
<TABLE>
<S>                                                           <C>           <C>
Liabilities (including $184,816 and $294,384 payable to
  unitholders in 1997 and 1996, respectively)...............  $1,167,149    $1,279,111
Corpus......................................................           2             2
Undistributed income........................................     836,358       778,138
                                                              ----------    ----------
                                                              $2,003,509    $2,057,251
                                                              ==========    ==========
</TABLE>
 
                              STATEMENTS OF INCOME
 
<TABLE>
<CAPTION>
                                                            YEAR ENDED JUNE 30
                                                  --------------------------------------
                                                     1997          1996          1995
                                                  ----------    ----------    ----------
<S>                                               <C>           <C>           <C>
Income..........................................  $1,065,247    $1,273,021    $1,053,843
Expenses........................................      70,531        76,262        88,917
                                                  ----------    ----------    ----------
     Income before Federal income taxes.........     994,716     1,196,759       964,926
Federal income taxes of Tidelands' subsidiary...      16,300        17,600        12,377
                                                  ----------    ----------    ----------
     Net income.................................  $  978,416    $1,179,159    $  952,549
                                                  ==========    ==========    ==========
</TABLE>
 
     Tidelands is a registrant with the Securities and Exchange Commission and
has filed a Form 10-K as of December 31, 1996.
 
(3) OVERPAID ROYALTIES
 
     The Trust and Chevron entered into agreements, effective October 31, 1988,
that determine the values to be used in calculating payments to the Trust for
sales of gas from leases identified in the agreements, beginning November 1,
1987 and ending October 31, 1989. Royalty payments were made based on values
 
                                       17
<PAGE>   20
 
                     MARINE PETROLEUM TRUST AND SUBSIDIARY
 
           NOTES TO CONSOLIDATED FINANCIAL STATEMENTS -- (CONTINUED)
                        THREE YEARS ENDED JUNE 30, 1997
 
higher than those set forth in the agreements, and the Trust has recognized a
potential liability to cover the estimated amount that Chevron may be entitled
to recover from future payments.
 
(4) SUMMARY OF QUARTERLY FINANCIAL DATA (UNAUDITED)
 
     The following quarterly financial information for 1997 and 1996 is
unaudited; however, in the opinion of management, all adjustments necessary to a
fair statement of the results of operations for the interim periods have been
included.
 
<TABLE>
<CAPTION>
                                                                                     NET
                                             OIL AND GAS                            INCOME
                                              ROYALTIES    EXPENSES   NET INCOME   PER UNIT
                                             -----------   --------   ----------   --------
<S>                                          <C>           <C>        <C>          <C>
Quarter ended:
  September 30, 1996.......................   $  861,011    27,858       927,649      .46
  December 31, 1996........................    1,085,760    47,881     1,137,457      .57
  March 31, 1997...........................      882,772    36,520       954,040      .48
  June 30, 1997............................      815,461    30,804       895,051      .45
                                              ----------   -------     ---------     ----
                                              $3,645,004   143,063     3,914,197     1.96
                                              ==========   =======     =========     ====
Quarter ended:
  September 30, 1995.......................   $  535,806    20,636       629,913      .32
  December 31, 1995........................      543,819    36,870       623,334      .31
  March 31, 1996...........................      845,030    31,081       924,907      .46
  June 30, 1996............................      916,894    32,238     1,007,698      .50
                                              ----------   -------     ---------     ----
                                              $2,841,549   120,825     3,185,852     1.59
                                              ==========   =======     =========     ====
</TABLE>
 
(5) SUPPLEMENTAL INFORMATION RELATING TO OIL AND GAS RESERVES (UNAUDITED)
 
     Oil and gas reserve information relating to the Trust's and Tidelands'
royalty interests is not presented because such information is not available to
the Trust or Tidelands. The Trust's share of oil and gas produced for its
royalty interests and the Trust's equity in oil and gas produced for Tidelands'
royalty interests were as follows:
 
<TABLE>
<CAPTION>
                                                            1997      1996      1995
                                                           -------   -------   -------
<S>                                                        <C>       <C>       <C>
Trust:
  Oil (barrels)..........................................   71,776    76,689    57,425
                                                           =======   =======   =======
  Gas (mcf)..............................................  879,452   700,209   594,152
                                                           =======   =======   =======
Tidelands:
  Oil (barrels)..........................................    2,780     2,847     2,315
                                                           =======   =======   =======
  Gas (mcf)..............................................  118,002   175,846   167,095
                                                           =======   =======   =======
</TABLE>
 
                                       18
<PAGE>   21
 
                                   SIGNATURES
 
     Pursuant to the requirements of Section 13 or 15(d) 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.
 
                                            MARINE PETROLEUM TRUST
                                              (Registrant)
 
                                            By: NATIONSBANK OF TEXAS, N.A.
                                              in its capacity as trustee of
                                              Marine Petroleum Trust and not in
                                              its individual capacity or
                                              otherwise
 
                                            By:      /s/ PATRICIA COX
                                              ----------------------------------
                                                         Patricia Cox
                                                        Vice President
 
Date: September 25, 1997
 
     Pursuant to the requirements of the Securities Exchange Act of 1934, this
report has been signed below by the following persons on behalf of the
registrant and in the capacities and on the dates indicated.
 
                                            NATIONSBANK OF TEXAS, N.A.
                                              in its capacity as trustee of
                                              Marine Petroleum Trust and not in
                                              its individual capacity or
                                              otherwise
 
                                            By:      /s/ PATRICIA COX
                                              ----------------------------------
                                                         Patricia Cox
                                                        Vice President
 
Date: September 25, 1997
 
                                                     /s/ R. RAY BELL
                                            ------------------------------------
                                                        R. Ray Bell
                                             (Acting Chief Accounting Officer)
 
Date: September 25, 1997
 
                                       19
<PAGE>   22
 
                                 EXHIBIT INDEX
 
<TABLE>
<CAPTION>
EXHIBIT NO.                                        DESCRIPTION
-----------                                        -----------
<C>          <S>                                                                                     <C>
     (21)    -- List of the subsidiaries of the Registrant.
     (27)    -- Financial Data Schedule.
</TABLE>