<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 September 30, 1997

                                       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 33-15998-12


                          SWIFT ENERGY MANAGED PENSION
                         ASSETS PARTNERSHIP 1991-A LTD.
             (Exact name of registrant as specified in its charter)

<TABLE>
<S>                                           <C>
                  Texas                                   76-0325631
(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 MANAGED PENSION
                         ASSETS PARTNERSHIP 1991-A, LTD.

                                      INDEX



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

      Balance Sheets

          - September 30, 1997 and December 31, 1996                                 3

      Statements of Operations

          - Three month and nine month periods ended September 30, 1997 and 1996     4

      Statements of Cash Flows

          - Nine month periods ended September 30, 1997 and 1996                     5

      Notes to Financial Statements                                                  6

ITEM 2.    Management's Discussion and Analysis of Financial
               Condition and Results of Operations                                   9

PART II.    OTHER INFORMATION                                                       11


SIGNATURES                                                                          12
</TABLE>


<PAGE>

                          SWIFT ENERGY MANAGED PENSION
                         ASSETS PARTNERSHIP 1991-A, LTD.
                                 BALANCE SHEETS



<TABLE>
<CAPTION>
                                                                                        September 30,        December 31,
                                                                                            1997                 1996
                                                                                       ---------------     ----------------
                                                                                        (Unaudited)
         <S>                                                                           <C>                  <C>           
         ASSETS:

         Current Assets:
              Cash and cash equivalents                                                $        1,245       $        1,208
              Nonoperating interests income receivable                                         28,025               11,948
                                                                                       ---------------     ----------------
                   Total Current Assets                                                        29,270               13,156
                                                                                       ---------------     ----------------
         Nonoperating interests in oil and gas
              properties, using full cost accounting                                        1,611,453            1,596,442
         Less-Accumulated amortization                                                     (1,352,014)          (1,282,143)
                                                                                       ---------------     ----------------
                                                                                              259,439              314,299
                                                                                       ---------------     ----------------
                                                                                       $      288,709       $      327,455
                                                                                       ===============     ================


         LIABILITIES AND PARTNERS' CAPITAL:

         Current Liabilities:
              Payable related to excess costs                                          $      276,820       $      308,068
                                                                                       ---------------     ----------------

         Partners' Capital                                                                     11,889               19,387
                                                                                       ---------------     ----------------
                                                                                       $      288,709       $      327,455
                                                                                       ===============     ================
</TABLE>



                 See accompanying notes to financial statements.

                                        3


<PAGE>

                          SWIFT ENERGY MANAGED PENSION
                         ASSETS PARTNERSHIP 1991-A, LTD.
                            STATEMENTS OF OPERATIONS
                                   (Unaudited)




<TABLE>
<CAPTION>
                                                      Three Months Ended                Nine Months Ended
                                                         September 30,                    September 30,
                                              ---------------------------------  ---------------------------------
                                                   1997              1996             1997              1996
                                              ---------------   ---------------  ---------------   ---------------
<S>                                           <C>               <C>              <C>               <C>            
REVENUES:
   Income from nonoperating interests         $        28,720   $         2,606  $        68,475   $        13,718
   Interest income                                         16                14               37                35
                                              ---------------   ---------------  ---------------   ---------------
                                                       28,736             2,620           68,512            13,753
                                              ---------------   ---------------  ---------------   ---------------

COSTS AND EXPENSES:
   Amortization                                        14,040            18,186           69,871           215,461
   General and administrative                           1,915             2,606            6,139            13,720
                                              ---------------   ---------------  ---------------   ---------------
                                                       15,955            20,792           76,010           229,181
                                              ---------------   ---------------  ---------------   ---------------
NET INCOME (LOSS)                             $        12,781   $       (18,172) $        (7,498)  $      (215,428)
                                              ===============   ===============  ===============   ===============



Limited Partners' net income (loss)
   per unit                                   $           .88   $         (1.25) $          (.52)  $        (14.87)
                                              ===============   ===============  ===============   ===============
</TABLE>



                 See accompanying notes to financial statements.

                                        4


<PAGE>

                          SWIFT ENERGY MANAGED PENSION
                         ASSETS PARTNERSHIP 1991-A, LTD.
                            STATEMENTS OF CASH FLOWS
                                   (Unaudited)

<TABLE>
<CAPTION>
                                                                                           Nine Months Ended
                                                                                             September 30,
                                                                               ----------------------------------------
                                                                                     1997                    1996
                                                                               ---------------          ---------------
<S>                                                                             <C>                     <C>
CASH FLOWS FROM OPERATING ACTIVITIES:
    Income (Loss)                                                               $       (7,498)         $      (215,428)
    Adjustments to reconcile income (loss) to
      net cash provided by operations:
      Amortization                                                                      69,871                  215,461
      Change in assets and liabilities:
        (Increase) decrease in nonoperating interests income receivable                (16,077)                  11,700
        Increase (decrease) in accounts payable
          and accrued liabilities                                                           --                   (6,651)
                                                                               ---------------          ---------------
               Net cash provided by (used in) operating activities                      46,296                    5,082
                                                                               ---------------          ---------------
CASH FLOWS FROM INVESTING ACTIVITIES:
    Additions to nonoperating interests in oil and gas properties                      (15,011)                 (16,820)
    Proceeds from sale of nonoperating interests
      in oil and gas properties                                                             --                      160
    Increase (decrease) in payable related to excess costs                             (31,248)                  13,411
                                                                               ---------------          ---------------
               Net cash provided by (used in) investing activities                     (46,259)                  (3,249)
                                                                               ---------------          ---------------
CASH FLOWS FROM FINANCING ACTIVITIES:
    Cash distributions to partners                                                          --                   (1,798)
                                                                               ---------------          ---------------
NET INCREASE (DECREASE) IN CASH AND CASH EQUIVALENTS                                        37                       35
                                                                               ---------------          ---------------
CASH AND CASH EQUIVALENTS AT BEGINNING OF PERIOD                                         1,208                    1,149
                                                                               ---------------          ---------------
CASH AND CASH EQUIVALENTS AT END OF PERIOD                                      $        1,245          $         1,184
                                                                               ===============          ===============
Supplemental disclosure of cash flow information:
    Cash paid during the period for interest                                    $           --          $        22,326
                                                                               ===============          ===============
</TABLE>



                 See accompanying notes to financial statements.

                                        5


<PAGE>

                          SWIFT ENERGY MANAGED PENSION
                         ASSETS PARTNERSHIP 1991-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,  1996  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)  Organization and Terms of Partnership Agreement -

                  Swift Energy Managed Pension Assets Partnership 1991-A,  Ltd.,
        a Texas limited partnership ("the Partnership"), was formed on March 31,
        1991,  for the purpose of purchasing net profits  interests,  overriding
        royalty  interests and royalty  interests  (collectively,  "nonoperating
        interests") in producing oil and gas properties  within the  continental
        United States. Swift Energy Company ("Swift"), a Texas corporation,  and
        VJM Corporation  ("VJM"),  a California  corporation,  serve as Managing
        General  Partner  and  Special  General  Partner  of  the   Partnership,
        respectively.  The general  partners  are required to  contribute  up to
        1/99th of limited partner net  contributions.  The 173 limited  partners
        made total capital contributions of $1,448,986.

                  Nonoperating  interests  acquisition  costs and the management
        fee are borne 99 percent by the limited  partners and one percent by the
        general  partners.  Organization and syndication costs were borne solely
        by the limited partners.

                  Generally,  all continuing costs (including development costs,
        operating costs,  general and  administrative  reimbursements and direct
        expenses) and revenues are allocated 90 percent to the limited  partners
        and ten percent to the general partners. If prior to partnership payout,
        however,  the cash  distribution  rate for a  certain  period  equals or
        exceeds  17.5  percent,  then for the  following  calendar  year,  these
        continuing  costs and  revenues  will be  allocated  85  percent  to the
        limited  partners  and  15  percent  to  the  general  partners.   After
        partnership  payout,  continuing  costs and  revenues  will be shared 85
        percent by the limited partners, and 15 percent by the general partners,
        even if the  cash  distribution  rate is less  than  17.5  percent.  The
        general partners expect to present for limited partners consideration in
        1997, a proposal to liquidate the partnership.

(3)  Significant Accounting Policies -

      Use of Estimates --

                  The  preparation  of financial  statements in conformity  with
        generally accepted  accounting  principles  requires  management to make
        estimates and assumptions that affect the reported amounts of assets and
        liabilities  at the date of the  financial  statements  and the reported
        amounts of revenues and expenses  during the  reporting  period.  Actual
        results could differ from estimates. Certain reclassifications have been
        made to prior year amounts to conform to the current year presentation.


                                       6


<PAGE>

                          SWIFT ENERGY MANAGED PENSION
                         ASSETS PARTNERSHIP 1991-A, LTD.
                    NOTES TO FINANCIAL STATEMENTS (CONTINUED)
                                   (UNAUDITED)


     Nonoperating Interests in Oil and Gas Properties --

                  For financial  reporting purposes the Partnership  follows the
        "full-cost"  method of accounting for nonoperating  interests in oil and
        gas property costs. Under this method of accounting,  all costs incurred
        in the acquisition of  nonoperating  interests in oil and gas properties
        are capitalized.  The unamortized cost of nonoperating  interests in oil
        and gas  properties is limited to the "ceiling  limitation"  (calculated
        separately for the Partnership,  limited partners and general partners).
        The  "ceiling  limitation"  is  calculated  on  a  quarterly  basis  and
        represents the estimated future net revenues from nonoperating interests
        in proved  properties  using current  prices  discounted at ten percent.
        Proceeds from the sale or disposition of  nonoperating  interests in oil
        and  gas  properties  are  treated  as a  reduction  of the  cost of the
        nonoperating  interests  with no gains or  losses  recognized  except in
        significant transactions.

                  The Partnership computes the provision for amortization of oil
        and gas properties on the units-of-production method. Under this method,
        the provision is calculated by multiplying the total unamortized cost of
        oil and gas  properties  by an overall rate  determined  by dividing the
        physical  units of oil and gas  produced  during the period by the total
        estimated proved oil and gas reserves at the beginning of the period.

                  The calculation of the "ceiling  limitation" and the provision
        for  depreciation,  depletion and  amortization is based on estimates of
        proved reserves. There are numerous uncertainties inherent in estimating
        quantities  of proved  reserves  and in  projecting  the future rates of
        production,  timing and plan of development. The accuracy of any reserve
        estimate  is a  function  of  the  quality  of  available  data  and  of
        engineering  and  geological  interpretation  and  judgment.  Results of
        drilling,  testing and production subsequent to the date of the estimate
        may justify revision of such estimate.  Accordingly,  reserve  estimates
        are  often  different  from  the  quantities  of oil  and gas  that  are
        ultimately recovered.

(4)  Related-Party Transactions -

                  An  affiliate  of  the  Special  General  Partner,  as  Dealer
        Manager,  received  $36,225 for managing and  overseeing the offering of
        the limited  partnership units. A one-time management fee of $36,225 was
        paid to Swift for services performed for the Partnership.

                  The  Partnership  entered  into a Net Profits  and  Overriding
        Royalty Interests Agreement ("NP/OR Agreement") with Swift Energy Income
        Partners 1991-A, Ltd. ("Operating  Partnership"),  managed by Swift, for
        the purpose of acquiring nonoperating interests in producing oil and gas
        properties.   Under  terms  of  the  NP/OR   Agreement,   the  Operating
        Partnership will convey to the Partnership nonoperating interests in the
        aggregate net profits (i.e., oil and gas sales net of related  operating
        costs) of the properties  acquired equal to its  proportionate  share of
        the property acquisition costs.

(5)  Vulnerability Due to Certain Concentrations -

                  The  Company'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.

                  The Partnership extends credit 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.


                                       7


<PAGE>

                          SWIFT ENERGY MANAGED PENSION
                         ASSETS PARTNERSHIP 1991-A, LTD.
                    NOTES TO FINANCIAL STATEMENTS (CONTINUED)
                                   (UNAUDITED)


(6)  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.


                                       8


<PAGE>

                          SWIFT ENERGY MANAGED PENSION
                         ASSETS PARTNERSHIP 1991-A, LTD.
                MANAGEMENT'S DISCUSSION AND ANALYSIS OF FINANCIAL
                       CONDITION AND RESULTS OF OPERATIONS


GENERAL

         The  Partnership is formed for the purpose of investing in nonoperating
interests 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 results of
operations.  When the  Partnership  is formed,  it commences  its  "acquisition"
phase,  with all funds placed in short-term  investments  until required for the
acquisition of nonoperating interests.  Therefore,  the interest earned on these
pre-acquisition  investments  becomes the  primary  cash flow source for initial
partner  distributions.  As the Partnership acquires  nonoperating  interests in
producing properties,  net cash from ownership of nonoperating interests becomes
available  for  distribution,  along  with  the  investment  income.  After  all
partnership funds have been expended on nonoperating  interests in producing oil
and gas properties,  the Partnership enters its "operations"  phase. During this
phase,  income  from  nonoperating  interests  in oil  and gas  sales  generates
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  nonoperating  interests  in  acquired  oil and gas
properties,  when the sale of such  interests  is  economically  appropriate  or
preferable to continued operations.

LIQUIDITY AND CAPITAL RESOURCES

         The Partnership has completed acquisition of nonoperating  interests in
producing oil and gas  properties,  expending  all of the limited  partners' net
commitments available for property acquisitions.

         Under  the NP/OR  Agreement,  the  Managing  General  Partner  acquires
interests  in oil and gas  properties  from  outside  parties  and  sells  these
interests to an affiliated operating partnership,  who in turn creates and sells
to the Partnership  nonoperating interests in these same oil and gas properties.
The Managing General Partner expects funds available from net profits  interests
to be distributed to the partners.

RESULTS OF OPERATIONS

      The  following  analysis  explains  changes  in the  revenue  and  expense
categories  for the quarter  ended  September  30, 1997  (current  quarter) when
compared to the quarter ended September 30, 1996  (corresponding  quarter),  and
for the nine months ended September 30, 1997 (current period),  when compared to
the nine months ended September 30, 1996 (corresponding period).

Three Months Ended September 30, 1997 and 1996

      Oil and gas sales  increased  $4,635 or 23 percent in the third quarter of
1997 when  compared  to the  corresponding  quarter  in 1996,  primarily  due to
increased gas  production.  An increases of 44 percent in gas  production  had a
significant impact on partnership performance.  Also, current quarter gas prices
increased 7 percent or $.16/MCF  when  compared to third quarter 1996 gas prices
further contributing to increased revenues.

      Associated amortization expense increased 13 percent or $1,641.

      The  Partnership  recorded an additional  provision in amortization in the
third  quarter of 1996 for $5,787  when the  present  value,  discounted  at ten
percent, of estimated future net revenues from oil and gas properties, using the
guidelines of the Securities and Exchange Commission,  was below the fair market
value  originally  paid for oil and gas  properties.  The  additional  provision
results from the Managing General Partner's  determination  that the fair market
value  paid for  properties  may or may not  coincide  with  reserve  valuations
determined  according to guidelines of the Securities  and Exchange  Commission.
Using  prices in effect at  September  30,  1996,  the  Partnership  would  have
recorded an additional provision at September 30, 1996 in the amount of $95,682.


                                       9


<PAGE>

                          SWIFT ENERGY MANAGED PENSION
                         ASSETS PARTNERSHIP 1991-A, LTD.
                MANAGEMENT'S DISCUSSION AND ANALYSIS OF FINANCIAL
                 CONDITION AND RESULTS OF OPERATIONS (CONTINUED)


Nine Months Ended September 30, 1997 and 1996

      Oil and gas sales increased $17,289 or 24 percent in the first nine months
of 1997 over the corresponding  period in 1996. An increase of 46 percent in gas
production  was a major  contributing  factor to the increased  revenues for the
period. Increased gas prices of 2 percent or $.05/MCF further contributed to the
increased revenues.

      Associated amortization expense increased 15 percent or $6,393.

      The  Partnership  recorded an additional  provision in amortization in the
first nine months of 1997 and 1996 for $21,161 and $173,144,  respectively, when
the present value,  discounted at ten percent,  of estimated future net revenues
from oil and gas properties, using the guidelines of the Securities and Exchange
Commission,  was below the fair  market  value  originally  paid for oil and gas
properties. The additional provision results from the Managing General Partner's
determination  that the fair  market  value paid for  properties  may or may not
coincide  with reserve  valuations  determined  according to  guidelines  of the
Securities and Exchange Commission.

      During 1997,  partnership  revenues  and costs will be shared  between the
limited partners and general partners in a 90:10 ratio.


                                       10


<PAGE>

                          SWIFT ENERGY MANAGED PENSION
                         ASSETS PARTNERSHIP 1991-A, LTD
                           PART II - OTHER INFORMATION




ITEM 5.    OTHER INFORMATION


                                     -NONE-





                                       11


<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 MANAGED PENSION
                                        ASSETS PARTNERSHIP 1991-A, LTD.
                                        (Registrant)

                             By:        SWIFT ENERGY COMPANY
                                        Managing General Partner


Date:  November 4, 1997      By:        /s/ John R. Alden
       ----------------                 ---------------------------------------
                                        John R. Alden
                                        Senior Vice President, Secretary
                                        and Principal Financial Officer

Date:  November 4, 1997      By:        /s/ Alton D. Heckaman, Jr.
       ----------------                 ---------------------------------------
                                        Alton D. Heckaman, Jr.
                                        Vice President, Controller
                                        and Principal Accounting Officer


                                       12