<PAGE>
                                  UNITED STATES
                       SECURITIES AND EXCHANGE COMMISSION

                             WASHINGTON, D.C. 20549

                                    FORM 10-Q



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


                  For the Quarterly Period Ended June 30, 2002

                                       OR


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


   For the Transition Period from ___________________ to _____________________


                         Commission File Number 0-13546

                                   ----------


                     APACHE OFFSHORE INVESTMENT PARTNERSHIP
             ------------------------------------------------------
             (Exact Name of Registrant as Specified in Its Charter)


                 Delaware                                       41-1464066
     -------------------------------                     ----------------------
     (State or Other Jurisdiction of                        (I.R.S. Employer
     Incorporation or Organization)                      Identification Number)

     Suite 100, One Post Oak Central                           77056-4400
  2000 Post Oak Boulevard, Houston, TX                         ----------
----------------------------------------                       (Zip Code)
(Address of Principal Executive Offices)


       Registrant's Telephone Number, Including Area Code: (713) 296-6000



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
requirements for the past 90 days.


                                  YES X   NO
                                     ---    ---


<PAGE>


                         PART I - FINANCIAL INFORMATION


ITEM 1 - FINANCIAL STATEMENTS


                     APACHE OFFSHORE INVESTMENT PARTNERSHIP
                               STATEMENT OF INCOME
                                   (UNAUDITED)


<Table>
<Caption>
                                                            FOR THE QUARTER                FOR THE SIX MONTHS
                                                            ENDED JUNE 30,                   ENDED JUNE 30,
                                                     ------------------------------   ------------------------------
                                                         2002            2001             2002            2001
                                                     --------------  --------------   --------------  --------------
<S>                                                  <C>             <C>              <C>             <C>
REVENUES:
    Oil and gas sales                                $   1,750,257   $   2,765,540    $   3,062,772   $   6,758,274
    Interest income                                          4,930          22,977           10,358          40,066
                                                     --------------  --------------   --------------  --------------

                                                         1,755,187       2,788,517        3,073,130       6,798,340
                                                     --------------  --------------   --------------  --------------

EXPENSES:
    Depreciation, depletion and amortization               598,747         490,398          988,673       1,232,187
    Lease operating expense                                150,186         150,386          325,339         286,781
    Administrative                                         115,000         126,000          230,000         261,000
                                                     --------------  --------------   --------------  --------------

                                                           863,933         766,784        1,544,012       1,779,968
                                                     --------------  --------------   --------------  --------------

NET INCOME                                           $     891,254   $   2,021,733    $   1,529,118   $   5,018,372
                                                     ==============  ==============   ==============  ==============

NET INCOME ALLOCATED TO:
    Managing Partner                                 $     260,352   $     470,456    $     453,585   $   1,169,165
    Investing Partners                                     630,902       1,551,277        1,075,533       3,849,207
                                                     --------------  --------------   --------------  --------------

                                                     $     891,254   $   2,021,733    $   1,529,118   $   5,018,372
                                                     ==============  ==============   ==============  ==============

NET INCOME PER INVESTING PARTNER UNIT                $         570   $       1,377    $         970   $       3,414
                                                     ==============  ==============   ==============  ==============

WEIGHTED AVERAGE INVESTING PARTNER
    UNITS OUTSTANDING                                      1,106.8         1,126.4          1,108.5         1,127.5
                                                     ==============  ==============   ==============  ==============
</Table>

                 The accompanying notes to financial statements
                     are an integral part of this statement.


                                       1
<PAGE>
                     APACHE OFFSHORE INVESTMENT PARTNERSHIP
                             STATEMENT OF CASH FLOWS
                                   (UNAUDITED)


<Table>
<Caption>
                                                                               FOR THE SIX MONTHS ENDED JUNE 30,
                                                                          ------------------------------------------
                                                                                 2002                     2001
                                                                          -----------------        -----------------

<S>                                                                       <C>                      <C>
CASH FLOWS FROM OPERATING ACTIVITIES:
    Net income                                                            $     1,529,118          $     5,018,372
    Adjustments to reconcile net income to net cash
       provided by operating activities:
          Depreciation, depletion and amortization                                988,673                1,232,187
          Changes in operating assets and liabilities:
              (Increase) decrease in accrued revenues receivable                  (52,203)                 582,633
              Increase (decrease) in accrued operating expenses payable           (47,027)                  36,549
              (Increase) decrease in receivable from/payable to
                  Apache Corporation                                             (201,284)                (665,131)
                                                                          -----------------        -----------------

          Net cash provided by operating activities                             2,217,277                6,204,610
                                                                          -----------------        -----------------

CASH FLOWS FROM INVESTING ACTIVITIES:
    Additions to oil and gas properties                                        (1,731,688)                (872,601)
    Non-cash portion of oil and gas property additions                           (151,937)                (388,000)
                                                                          -----------------        -----------------

          Net cash used in investing activities                                (1,883,625)              (1,260,601)
                                                                          -----------------        -----------------

CASH FLOWS FROM FINANCING ACTIVITIES:
    Repurchase of Partnership Units                                              (134,477)                 (64,226)
    Distributions to Investing Partners                                                --               (2,256,977)
    Distributions to Managing Partner, net                                       (469,396)              (1,321,014)
                                                                          -----------------        -----------------

          Net cash used in financing activities                                  (603,873)              (3,642,217)
                                                                          -----------------        -----------------

NET INCREASE IN CASH AND CASH EQUIVALENTS                                        (270,221)               1,301,792

CASH AND CASH EQUIVALENTS, BEGINNING OF YEAR                                    1,883,386                1,442,878
                                                                          -----------------        -----------------

CASH AND CASH EQUIVALENTS, END OF PERIOD                                  $     1,613,165          $     2,744,670
                                                                          =================        =================
</Table>

                 The accompanying notes to financial statements
                     are an integral part of this statement.


                                       2
<PAGE>


                     APACHE OFFSHORE INVESTMENT PARTNERSHIP
                                  BALANCE SHEET
                                   (UNAUDITED)


<Table>
<Caption>
                                                                               JUNE 30,                DECEMBER 31,
                                                                                2002                      2001
                                                                          -----------------        -----------------
<S>                                                                       <C>                      <C>
                                  ASSETS
CURRENT ASSETS:
    Cash and cash equivalents                                             $     1,613,165          $     1,883,386
    Accrued revenues receivable                                                   345,158                  292,955
                                                                          -----------------        -----------------

                                                                                1,958,323                2,176,341
                                                                          -----------------        -----------------

OIL AND GAS PROPERTIES, on the basis of full cost accounting:
    Proved properties                                                         178,140,411              176,408,723
    Less - Accumulated depreciation, depletion and amortization              (170,161,227)            (169,172,554)
                                                                          -----------------        -----------------

                                                                                7,979,184                7,236,169
                                                                          -----------------        -----------------

                                                                          $     9,937,507          $     9,412,510
                                                                          =================        =================

                     LIABILITIES AND PARTNERS' CAPITAL

CURRENT LIABILITIES:
    Accrued exploration and development                                   $       262,621          $       414,558
    Accrued operating expenses payable and other                                   65,157                  112,184
    Payable to Apache Corporation                                                 315,478                  516,762
                                                                          -----------------        -----------------

                                                                                  643,256                1,043,504
                                                                          -----------------        -----------------

PARTNERS' CAPITAL:
    Managing Partner                                                              140,417                  156,228
    Investing Partners (1,095.2 and 1,110.3 units outstanding,
       respectively)                                                            9,153,834                8,212,778
                                                                          -----------------        -----------------

                                                                                9,294,251                8,369,006
                                                                          -----------------        -----------------

                                                                          $     9,937,507          $     9,412,510
                                                                          =================        =================
</Table>


                 The accompanying notes to financial statements
                     are an integral part of this statement.


                                       3
<PAGE>


                     APACHE OFFSHORE INVESTMENT PARTNERSHIP
                          NOTES TO FINANCIAL STATEMENTS
                                   (UNAUDITED)


     The financial statements included herein have been prepared by the Apache
Offshore Investment Partnership (the Partnership), without audit, pursuant to
the rules and regulations of the Securities and Exchange Commission, and reflect
all adjustments which are, in the opinion of management, necessary for a fair
statement of the results for the interim periods, on a basis consistent with the
annual audited financial statements. All such adjustments are of a normal,
recurring nature. Certain information, accounting policies, and footnote
disclosures normally included in financial statements prepared in accordance
with generally accepted accounting principles have been omitted pursuant to such
rules and regulations, although the Partnership 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 the
summary of significant accounting policies and notes thereto included in the
Partnership's latest annual report on Form 10-K.


1. RECEIVABLE FROM/PAYABLE TO APACHE CORPORATION

     Payable to Apache Corporation, the Partnership's managing partner (Apache
or the Managing Partner), represents the net result of the Investing Partners'
revenue and expenditure transactions in the current month. Generally, cash in
this amount will be transferred to Apache in the month after the Partnership's
transactions are processed and the net results of operations are determined.


2. RIGHT OF PRESENTMENT

     As provided in the Amended Partnership Agreement, a first right of
presentment offer for 2002 of $8,686 per Unit, plus interest to the date of
payment, was made to Investing Partners in April 2002, based on a valuation date
of December 31, 2001. As a result, the Partnership purchased 15.1 Units in June
2002 for a total of $134,477. Investing partners will have a second right of
presentment during the fourth quarter of 2002, based on a valuation date of June
30, 2002.

     The Partnership is not in a position to predict how many Units will be
presented for repurchase during the fourth quarter of 2002 and cannot, at this
time, determine if the Partnership will have sufficient funds available to
repurchase any Units. The Partnership has no obligation to purchase any Units
presented to the extent it determines that it has insufficient funds for such
purchases. The Amended Partnership Agreement contains limitations on the number
of Units that the Partnership can repurchase, including a limit of 10 percent of
the outstanding Units on an annual basis.


3. NEW ACCOUNTING PRONOUNCEMENTS

     In June 2001, the Financial Accounting Standards Board issued Statement of
Financial Accounting Standards (SFAS) No. 143 "Accounting for Asset Retirement
Obligations." SFAS No. 143 addresses financial accounting and reporting for
obligations associated with the retirement of tangible long-lived assets and the
associated asset retirement costs. This statement requires companies to record
the fair value of legal obligations associated with the retirement of tangible
long-lived assets in the period in which it is incurred. The liability is
capitalized as part of the related long-lived asset's carrying amount. Over
time, accretion of the liability is recognized as an operating expense and the
capitalized cost is depreciated over the expected useful life of the related
asset. SFAS No. 143 is effective for fiscal years beginning after June 15, 2002,
with earlier adoption encouraged. The Partnership's asset retirement obligations
relate primarily to the dismantlement of offshore platforms. The Partnership
expects to adopt this new standard effective January 1, 2003. The Partnership is
currently evaluating the impact of adopting this new standard and accordingly
has not quantified the impact on the consolidated financial statements.


                                       4
<PAGE>


ITEM 2 - MANAGEMENT'S DISCUSSION AND ANALYSIS OF FINANCIAL CONDITION AND
         RESULTS OF OPERATIONS


RESULTS OF OPERATIONS

NET INCOME AND REVENUE

     The Partnership reported net income in the second quarter of 2002 of $.9
million, down 56 percent from the prior year period due to lower oil and gas
prices and production. Net income per Investing Partner Unit decreased 59
percent, from $1,377 per Unit to $570 per Unit.

     For the first half of 2002, net income totaled $1.5 million, or $970 per
Investing Partner Unit, down 70 percent and 72 percent, respectively, from $5
million, or $3,414 per Unit, in the same period last year. The decreases were
attributable to lower prices and decreases in gas production in 2002.

     Revenues for the quarter decreased 37 percent, falling from $2.8 million in
the second quarter of 2001 to $1.8 million in the second quarter of 2002. For
the first six months of 2002, revenues decreased 55 percent to $3.1 million.
Natural gas sales accounted for 59 percent of the Partnership's total revenues
during the first half of 2002 compared to 78 percent during the first half of
2001.

     The Partnership's oil and gas production volume and price information is
summarized in the following table (gas volumes presented in thousand cubic feet
(Mcf) per day):


<Table>
<Caption>
                                      FOR THE QUARTER ENDED JUNE 30,              FOR THE SIX MONTHS ENDED JUNE 30,
                                  --------------------------------------      ----------------------------------------
                                                                INCREASE                                    INCREASE
                                      2002          2001       (DECREASE)         2002          2001       (DECREASE)
                                  ------------  ------------  ------------    ------------  ------------  ------------
<S>                                   <C>           <C>           <C>             <C>           <C>           <C>
Gas volume - Mcf per day              3,414         4,677         (27%)           3,425         4,769         (28%)
Average gas price - per Mcf           $3.44         $4.72         (27%)           $2.91         $6.10         (52%)
Oil volume - barrels per day            297           312          (5%)             304           300           1%
Average oil price - per barrel       $25.20        $26.58          (5%)          $22.88        $27.44         (17%)
</Table>


SECOND QUARTER 2002 COMPARED TO SECOND QUARTER 2001

     Natural gas production revenues for the second quarter of 2002 totaled $1.1
million, down 47 percent from the second quarter of 2001. Natural gas prices
decreased 27 percent for the second quarter of 2002 compared to the year-earlier
period, dropping to $3.44 per Mcf. Natural gas volumes for the quarter declined
27 percent from a year ago due largely to natural production declines at South
Pass 83. Production also fell at North Padre Island 969 as production was
shut-in for a dispute with a pipeline company on increased fees charged for the
transportation of natural gas. Gas production at South Timbalier 295 was even
with the second quarter of 2001 as production added through drilling during the
second half of 2001 and first half of 2002 offset the impact of natural
depletion. As a result of drilling at South Timbalier 295 during 2002, the
Partnership brought the B-3 well on production in early May, and the B-2 well on
production on June 10th. The Partnership had previously brought the South
Timbalier 295 B-1 well on production in December 2001.

     The Partnership's crude oil production revenues for the second quarter of
2002 totaled $681,000, a 10 percent decrease from the second quarter of 2001.
The decrease in oil sales was attributable to a five percent decline in both the
Partnership's average realized oil price and crude oil production. Production
added through drilling at South Timbalier 295 partially offset natural depletion
on the Partnership's properties.

YEAR-TO-DATE 2002 COMPARED TO YEAR-TO-DATE 2001

     Gas sales for the first half of 2002 of $1.8 million decreased $3.5
million, or 66 percent, when compared to the same period in 2001. The
Partnership's average realized gas prices decreased $3.19 per Mcf when compared
with the first six months of 2001, negatively impacting sales by $2.8 million.
Daily gas production for the first half of 2002 also decreased 28 percent when
compared to the same period in 2001, negatively impacting revenues by $.7
million. Production decreases in 2002 were primarily due to natural declines in
production.


                                       5
<PAGE>


     For the six months ended June 30, 2002, oil sales decreased 16 percent to
$1.3 million when compared to the same period last year. The Partnership's oil
sales revenues were unfavorably impacted by a 17 percent decrease in average
realized oil price, partially offset by a one percent increase in daily oil
production. Production added through drilling at South Timbalier 295 during the
second half of 2001 and first half of 2002 more than offset the impact of
natural depletion.

     Declines in oil and gas production can be expected in future periods due to
natural depletion. Given the small number of producing wells owned by the
Partnership, and the fact that offshore wells tend to decline at a faster rate
than onshore wells, the Partnership's future production will be subject to more
volatility than those companies with greater reserves and longer-lived
properties.

OPERATING EXPENSES

     The Partnership's depreciation, depletion and amortization (DD&A) rate,
expressed as a percentage of oil and gas production revenues, was approximately
34 percent during the second quarter of 2002 compared to 18 percent during the
same period in 2001. For the first six months, the Partnership's DD&A rate
increased from 18 percent in 2001 to 32 percent in the current year.

     Lease operating expense (LOE) in the second quarter 2002 was essentially
even with the second quarter 2001. For the first half of 2002, LOE of $.3
million was up 13 percent from a year ago due to higher repair and maintenance
cost during the first quarter of 2002.


CASH FLOW, LIQUIDITY AND CAPITAL RESOURCES

CAPITAL RESOURCES AND LIQUIDITY

     The Partnership's primary capital resource is net cash provided by
operating activities, which was $2.2 million for the first half of 2002. Net
cash provided by operating activities in 2002 was down 64 percent from a year
ago primarily due to lower prices and gas production. Future cash flows will be
influenced by fluctuations in product prices, production levels and operating
costs.

CAPITAL COMMITMENTS

     The Partnership's primary needs for cash are for operating expenses,
drilling and recompletion expenditures, distributions to Investing Partners, and
the purchase of Units offered by Investing Partners under the right of
presentment.

     During the first six months of 2002, the Partnership's oil and gas property
additions totaled $1.7 million, which primarily related to drilling and
recompletion projects at South Timbalier Block 295. The Partnership participated
in drilling three wells (B-2, B-3 and B-4) at South Timbalier 295. The B-2 and
B-3 wells were brought on production during the second quarter of 2002, and the
B-4 well was brought on production after the end of the second quarter. The
Partnership anticipates capital expenditures of approximately $.4 million for
the remainder of 2002. Such estimates may change based on realized prices,
drilling results or changes by the operator to the development plan.

     The Partnership made no distributions to Investing Partners during the
first six months of 2002 due to low oil and gas price realizations during the
first quarter and the comparatively high level of capital cost from drilling
activities during the first half. The amount of future distributions will be
dependent on actual and expected production levels, realized and expected oil
and gas prices, expected drilling and recompletion expenditures, and prudent
cash reserves for future dismantlement and abandonment costs that will be
incurred after the Partnership's reserves are depleted. The Partnership
anticipates that it will make a distribution to the Investing Partners during
the second half of 2002, utilizing a portion of the cash balances currently on
hand and cash from operating activities in the third quarter of this year.

     As provided in the Amended Partnership Agreement, a first right of
presentment offer for 2002 of $8,686 per Unit, plus interest to the date of
payment, was made to Investing Partners in April 2002, based on a valuation date
of December 31, 2001. As a result, the Partnership purchased 15.1 Units in June
2002 for a total of $134,477. Investing partners will have a second right of
presentment during the fourth quarter of 2002, based on a valuation date of June
30, 2002.


                                       6
<PAGE>


     The Partnership is not in a position to predict how many Units will be
presented for repurchase during the fourth quarter of 2002 and cannot, at this
time, determine if the Partnership will have sufficient funds available to
repurchase any Units. The Partnership has no obligation to purchase any Units
presented to the extent it determines that it has insufficient funds for such
purchases. The Amended Partnership Agreement contains limitations on the number
of Units that the Partnership can repurchase, including a limit of 10 percent of
the outstanding Units on an annual basis.


FORWARD-LOOKING STATEMENTS AND RISK

     Certain statements in this report, including statements of the future
plans, objectives, and expected performance of the Partnership, are
forward-looking statements that are dependent on certain events, risks and
uncertainties that may be outside the Partnership's control, and which could
cause actual results to differ materially from those anticipated. Some of these
include, but are not limited to, the market prices of oil and gas, economic and
competitive conditions, inflation rates, legislative and regulatory changes,
financial market conditions, political and economic uncertainties of foreign
governments, future business decisions, and other uncertainties, all of which
are difficult to predict.

     There are numerous uncertainties inherent in estimating quantities of
proved oil and gas reserves and in projecting future rates of production and
timing of development expenditures. The total amount or timing of actual future
production may vary significantly from reserves and production estimates. The
drilling of exploratory wells can involve significant risks, including those
related to timing, success rates and cost overruns. Lease and rig availability,
complex geology and other factors can affect these risks. Fluctuations in oil
and gas prices, or a prolonged period of low prices, may substantially adversely
affect the Partnership's financial position, results of operations and cash
flows.


COMMODITY RISK

     The Partnership's major market risk exposure is in the pricing applicable
to its oil and gas production. Realized pricing is primarily driven by the
prevailing worldwide price for crude oil and spot prices applicable to its
natural gas production. Historically, prices received for oil and gas production
have been volatile and unpredictable and price volatility is expected to
continue. The Partnership has not used derivative financial instruments or
otherwise engaged in hedging activities during 2001 or the first six months of
2002.


                                       7
<PAGE>


PART II - OTHER INFORMATION


ITEM 1.      LEGAL PROCEEDINGS

             None.

ITEM 2.      CHANGES IN SECURITIES

             None.

ITEM 3.      DEFAULTS UPON SENIOR SECURITIES

             None.

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

             None.

ITEM 5.      OTHER INFORMATION

             None.

ITEM 6.      EXHIBITS AND REPORTS ON FORM 8-K

             a. Exhibits

                99.1  -  Certification of Chief Executive Officer and Chief
                         Financial Officer

             b. Reports on Form 8-K - None.


                                       8
<PAGE>


                                   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.


                                      APACHE OFFSHORE INVESTMENT PARTNERSHIP
                                      By:   Apache Corporation, General Partner



Dated:    August 12, 2002             /s/ Roger B. Plank
                                      -----------------------------------------
                                      Roger B. Plank
                                      Executive Vice President and Chief
                                      Financial Officer


Dated:    August 12, 2002             /s/ Thomas L. Mitchell
                                      -----------------------------------------
                                      Thomas L. Mitchell
                                      Vice President and Controller
                                      (Chief Accounting Officer)