<PAGE>

                                    FORM 10-Q


                       SECURITIES AND EXCHANGE COMMISSION

                             Washington, D.C. 20549


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

                  For the quarterly period ended June 30, 1998

                                       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 0-17024


                    SWIFT ENERGY INCOME PARTNERS 1987-A, LTD.
             (Exact name of registrant as specified in its charter)
<TABLE>
<S>                                           <C>       
                  Texas                                   76-0215132
(State or other jurisdiction of organization) (I.R.S. Employer Identification No.)
</TABLE>

                        16825 Northchase Drive, Suite 400
                              Houston, Texas 77060
                    (Address of principal executive offices)
                                   (Zip Code)

                                  (281)874-2700
              (Registrant's telephone number, including area code)

                                      None
              (Former name, former address and former fiscal year,
                          if changed since last report)


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>


                    SWIFT ENERGY INCOME PARTNERS 1987-A, LTD.

                                      INDEX




<TABLE>
<CAPTION>
PART I.    FINANCIAL INFORMATION                                                         PAGE
      <S>                                                                                 <C>
      ITEM 1.    Financial Statements

            Balance Sheets

                - June 30, 1998 and December 31, 1997                                      3

            Statements of Operations

                - Three month and six month periods ended June 30, 1998 and 1997           4

            Statements of Cash Flows

                - Six month periods ended June 30, 1998 and 1997                           5

            Notes to Financial Statements                                                  6

      ITEM 2.    Management's Discussion and Analysis of Financial
                     Condition and Results of Operations                                   7

PART II.    OTHER INFORMATION                                                              9


SIGNATURES                                                                                10
</TABLE>




<PAGE>

                    SWIFT ENERGY INCOME PARTNERS 1987-A, LTD.
                                 BALANCE SHEETS



<TABLE>
<CAPTION>
                                                                                           June 30,           December 31,
                                                                                             1998                 1997
                                                                                       ---------------      ---------------
                                                                                         (Unaudited)
         <S>                                                                           <C>                  <C>           
         ASSETS:

         Current Assets:
              Cash and cash equivalents                                                $        1,722       $        1,095
              Oil and gas sales receivable                                                    126,493              393,020
              Other                                                                             9,096                6,917
                                                                                       ---------------      ---------------
                  Total Current Assets                                                        137,311              401,032
                                                                                       ---------------      ---------------

         Gas Imbalance Receivable                                                                 374                   --
                                                                                       ---------------      ---------------

         Oil and Gas Properties, using full cost
              accounting                                                                   13,747,558           13,697,598
         Less-Accumulated depreciation, depletion
              and amortization                                                            (11,254,897)         (11,173,762)
                                                                                       ---------------      ---------------
                                                                                            2,492,661            2,523,836
                                                                                       ---------------      ---------------
                                                                                       $    2,630,346       $    2,924,868
                                                                                       ===============      ===============

         LIABILITIES AND PARTNERS' CAPITAL:

         Current Liabilities:
              Accounts Payable                                                         $       75,708       $      104,965
                                                                                       ---------------      ---------------

         Deferred Revenues                                                                    115,737              133,437

         Limited Partners' Capital (15,071.79 Limited Partnership Units;
                                   $1,000 per unit)                                         2,345,433            2,565,085
         General Partners' Capital                                                             93,468              121,381
                                                                                       ---------------      ---------------
                  Total Partners' Capital                                                   2,438,901            2,686,466
                                                                                       ---------------      ---------------
                                                                                       $    2,630,346       $    2,924,868
                                                                                       ==============       ===============
</TABLE>


                 See accompanying notes to financial statements.

                                        3


<PAGE>

                    SWIFT ENERGY INCOME PARTNERS 1987-A, LTD.
                            STATEMENTS OF OPERATIONS
                                   (Unaudited)




<TABLE>
<CAPTION>
                                                     Three Months Ended                  Six Months Ended
                                                          June 30,                           June 30,
                                              ---------------------------------  ---------------------------------
                                                   1998              1997             1998              1997
                                              ---------------   ---------------  ---------------   ---------------
<S>                                           <C>               <C>              <C>               <C>            
REVENUES:
   Oil and gas sales                          $       109,476   $       107,917  $       157,457   $       289,414
   Interest income                                      1,384               582            3,075             1,046
   Other                                                  505             1,557              894             3,398
                                              ---------------   ---------------  ---------------   ---------------
                                                      111,365           110,056          161,426           293,858
                                              ---------------   ---------------  ---------------   ---------------

COSTS AND EXPENSES:
   Lease operating                                     41,441            59,083           98,585           112,116
   Production taxes                                     4,920             4,421            8,149            14,300
   Depreciation, depletion
      and amortization                                 51,898            39,116           81,135            79,358
   General and administrative                          35,230            39,415           75,808            75,614
                                              ---------------   ---------------  ---------------   ---------------
                                                      133,489           142,035          263,677           281,388
                                              ---------------   ---------------  ---------------   ---------------
NET INCOME (LOSS)                             $       (22,124)  $       (31,979) $      (102,251)  $        12,470
                                              ===============   ===============  ===============   ===============



Limited Partners' net income (loss)
   per unit                                   $         (1.47)  $         (2.12) $         (6.78)  $           .83
                                              ===============   ===============  ===============   ===============
</TABLE>


                 See accompanying notes to financial statements.

                                        4


<PAGE>


                    SWIFT ENERGY INCOME PARTNERS 1987-A, LTD.
                            STATEMENTS OF CASH FLOWS
                                   (Unaudited)


<TABLE>
<CAPTION>
                                                                                            Six Months Ended
                                                                                                June 30,
                                                                               ----------------------------------------
                                                                                     1998                    1997
                                                                               ---------------         ----------------
<S>                                                                             <C>                     <C>            
CASH FLOWS FROM OPERATING ACTIVITIES:
    Income (loss)                                                               $     (102,251)         $        12,470
    Adjustments to reconcile income (loss) to
      net cash provided by operations:
      Depreciation, depletion and amortization                                          81,135                   79,358
      Change in gas imbalance receivable
          and deferred revenues                                                        (18,074)                  (1,439)
      Change in assets and liabilities:
        (Increase) decrease in oil and gas sales receivable                            266,527                  134,123
        (Increase) decrease in other current assets                                     (2,179)                      --
        Increase (decrease) in accounts payable                                        (29,257)                (106,132)
                                                                               ---------------          ---------------
      Net cash provided by (used in) operating activities                              195,901                  118,380
                                                                               ---------------          ---------------
CASH FLOWS FROM INVESTING ACTIVITIES:
    Additions to oil and gas properties                                                (49,960)                  (2,125)
    Proceeds from sales of oil and gas properties                                           --                    2,476
    (Increase) decrease in receivable due to property disposition                           --                   71,724
                                                                               ---------------          ---------------
      Net cash provided by (used in) investing activities                              (49,960)                  72,075
                                                                               ---------------          ---------------
CASH FLOWS FROM FINANCING ACTIVITIES:
    Cash distributions to partners                                                    (145,314)                (190,438)
                                                                               ---------------          ---------------
NET INCREASE (DECREASE) IN CASH AND CASH EQUIVALENTS                                       627                       17
                                                                               ---------------          ---------------
CASH AND CASH EQUIVALENTS AT BEGINNING OF PERIOD                                         1,095                    1,040
                                                                               ---------------          ---------------
CASH AND CASH EQUIVALENTS AT END OF PERIOD                                      $        1,722          $         1,057
                                                                               ===============          ===============
</TABLE>


                 See accompanying notes to financial statements.

                                        5

<PAGE>


                    SWIFT ENERGY INCOME PARTNERS 1987-A, LTD.
                          NOTES TO FINANCIAL STATEMENTS
                                   (UNAUDITED)


(1)  General Information -

                  The financial statements included herein have been prepared by
        the  Partnership  and are  unaudited  except  for the  balance  sheet at
        December  31,  1997  which has been  taken  from the  audited  financial
        statements at that date. The financial  statements reflect  adjustments,
        all of which  were of a  normal  recurring  nature,  which  are,  in the
        opinion  of  the  managing   general   partner   necessary  for  a  fair
        presentation.  Certain  information  and footnote  disclosures  normally
        included in financial  statements  prepared in accordance with generally
        accepted  accounting  principles have been omitted pursuant to the rules
        and regulations of the Securities and Exchange Commission  ("SEC").  The
        Partnership  believes adequate disclosure is provided by the information
        presented.  The financial  statements should be read in conjunction with
        the audited  financial  statements  and the notes included in the latest
        Form 10-K.

(2)  Gas Imbalances -

                  The Partnership  recognizes its ownership  interest in natural
        gas  production as revenue.  Actual  production  quantities  sold may be
        different than the  Partnership's  ownership share in a given period. If
        the  Partnership's  sales exceed its ownership share of production,  the
        differences are recorded as deferred revenue. Gas balancing  receivables
        are  recorded  when the  Partnership's  ownership  share  of  production
        exceeds sales.

(3)  Vulnerability Due to Certain Concentrations -

                  The  Partnership's  revenues are primarily the result of sales
        of its oil and natural gas production.  Market prices of oil and natural
        gas may fluctuate and adversely affect operating results.

                  In the normal  course of  business,  the  Partnership  extends
        credit,  primarily in the form of monthly oil and gas sales receivables,
        to various  companies  in the oil and gas  industry  which  results in a
        concentration  of credit risk. This  concentration of credit risk may be
        affected by changes in economic or other  conditions and may accordingly
        impact the  Partnership's  overall  credit risk.  However,  the Managing
        General  Partner  believes  that  the  risk is  mitigated  by the  size,
        reputation, and nature of the companies to which the Partnership extends
        credit.  In  addition,   the  Partnership  generally  does  not  require
        collateral or other security to support customer receivables.

(4)  Fair Value of Financial Instruments -

                  The Partnership's  financial  instruments  consist of cash and
        cash equivalents and short-term  receivables and payables.  The carrying
        amounts  approximate  fair value due to the highly  liquid nature of the
        short-term instruments.


                                       6

<PAGE>

                    SWIFT ENERGY INCOME PARTNERS 1987-A, LTD.
                MANAGEMENT'S DISCUSSION AND ANALYSIS OF FINANCIAL
                       CONDITION AND RESULTS OF OPERATIONS

GENERAL

      The  Partnership  was formed for the purpose of investing in producing oil
and gas properties  located within the  continental  United States.  In order to
accomplish  this,  the  Partnership  goes through two  distinct yet  overlapping
phases  with  respect  to its  liquidity  and  result  of  operations.  When the
Partnership  is formed,  it commences its  "acquisition"  phase,  with all funds
placed in short-term  investments until required for such property acquisitions.
The interest  earned on these  pre-acquisition  investments  becomes the primary
cash flow source for initial partner distributions.  As the Partnership acquires
producing   properties,   net  cash  from  operations   becomes   available  for
distribution,  along with the investment  income.  After  partnership funds have
been expended on producing oil and gas properties,  the  Partnership  enters its
"operations" phase. During this phase, oil and gas sales generate  substantially
all revenues,  and  distributions  to partners  reflect those  revenues less all
associated  partnership expenses.  The Partnership may also derive proceeds from
the sale of acquired oil and gas properties, when the sale of such properties is
economically appropriate or preferable to continued operation.

LIQUIDITY AND CAPITAL RESOURCES

      Oil and gas reserves are depleting  assets and therefore often  experience
significant  production  declines each year from the date of acquisition through
the end of the life of the  property.  The primary  source of  liquidity  to the
Partnership comes almost entirely from the income generated from the sale of oil
and gas produced from ownership  interests in oil and gas  properties.  Net cash
provided by  operating  activities  totaled  $195,901  and  $118,380 for the six
months ended June 30, 1998 and 1997, respectively.  This source of liquidity and
the related results of operations, and in turn cash distributions,  will decline
in  future  periods  as the oil and gas  produced  from  these  properties  also
declines while production and general and administrative costs remain relatively
stable making it unlikely that the  Partnership  will hold the properties  until
they are fully depleted,  but will likely liquidate when a substantial  majority
of the reserves  have been  produced.  The  Partnership  has expended all of the
partners' net commitments available for property acquisitions and development by
acquiring producing oil and gas properties. The partnership invests primarily in
proved  producing  properties with nominal levels of future costs of development
for  proven  but  undeveloped  reserves.  Significant  purchases  of  additional
reserves or extensive drilling activity are not anticipated.  Cash distributions
totaled  $145,314  and $190,438 for the six months ended June 30, 1998 and 1997,
respectively.

      The  Partnership  does  not  allow  for  additional  assessments  from the
partners  to fund  capital  requirements.  However,  funds  are  available  from
partnership  revenues,  borrowings  or  proceeds  from the  sale of  partnership
property.  The  Managing  General  Partners  believes  that the funds  currently
available to the partnership  will be adequate to meet any  anticipated  capital
requirements.

RESULTS OF OPERATIONS

      The  following  analysis  explains  changes  in the  revenue  and  expense
categories  for the quarter ended June 30, 1998 (current  quarter) when compared
to the quarter  ended June 30,  1997  (corresponding  quarter),  and for the six
months ended June 30, 1998  (current  period),  when  compared to the six months
ended June 30, 1997 (corresponding period).

Three Months Ended June 30, 1998 and 1997

      Oil and gas sales  increased  $1,559 or 2 percent in the second quarter of
1998 when  compared to the same period in 1997,  primarily  due to increased gas
prices and  production.  An increase in gas prices of 16 percent or $.27/MCF and
in  gas  production  of 14  percent  had a  significant  impact  on  partnership
performance.  Current quarter oil production  declined 36 percent and oil prices
declined 31 percent or $5.01/BBL when compared to second quarter 1997 production
volumes, partially offsetting the effect of increased gas prices and production.

      Associated depreciation expense increased 33 percent or $12,782.

                                       7

<PAGE>

                    SWIFT ENERGY INCOME PARTNERS 1987-A, LTD.
                MANAGEMENT'S DISCUSSION AND ANALYSIS OF FINANCIAL
                 CONDITION AND RESULTS OF OPERATIONS (CONTINUED)


Six Months Ended June 30, 1998 and 1997

      Oil and gas sales declined  $131,957 or 46 percent in the first six months
of 1998 when  compared to the  corresponding  period in 1997,  primarily  due to
decreased gas and oil prices.  A decline in gas prices of 26 percent or $.63/MCF
and in oil  prices  of 42  percent  or  $7.56/BBL  had a  significant  impact on
partnership performance. Also, current period oil and gas production declined 52
percent and 11 percent, respectively,  when compared to the same period in 1997,
further  contributing to decreased  revenues.  The partnership's sale of several
properties  in the  fourth  quarter  of 1997 had an impact  on 1998  partnership
production volumes.

      Associated  depreciation  expense  increased  2 percent  or $1,777 in 1998
compared to the first six months of 1997.

      During 1998,  partnership  revenues  and costs will be shared  between the
limited partners and general partners in a 90:10 ratio.


                                       8


<PAGE>


                    SWIFT ENERGY INCOME PARTNERS 1987-A, LTD.
                           PART II - OTHER INFORMATION



ITEM 5.    OTHER INFORMATION


                                     -NONE-




                                       9


<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.


                                              SWIFT ENERGY INCOME
                                              PARTNERS 1987-A, LTD.
                                              (Registrant)

                                   By:        SWIFT ENERGY COMPANY
                                              Managing General Partner


Date:     August 4, 1998           By:        /s/ John R. Alden
          --------------                      ----------------------------------
                                              John R. Alden
                                              Senior Vice President, Secretary
                                              and Principal Financial Officer

Date:     August 4, 1998           By:        /s/ Alton D. Heckaman, Jr.
          --------------                      ----------------------------------
                                              Alton D. Heckaman, Jr.
                                              Vice President, Controller
                                              and Principal Accounting Officer


                                       10