<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: 33-37983-05


                   SWIFT ENERGY PENSION PARTNERS 1991-C, LTD.
             (Exact name of registrant as specified in its charter)

<TABLE>
<S>                                           <C>
                  Texas                                    76-0350269
(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 PENSION PARTNERS 1991-C, 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 PENSION PARTNERS 1991-C, LTD.
                                 BALANCE SHEETS



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

         Current Assets:
              Cash and cash equivalents                                                $        1,550       $        1,505
              Nonoperating interests income receivable                                         57,567               70,414
                                                                                       ---------------     ----------------
                   Total Current Assets                                                        59,117               71,919
                                                                                       ---------------     ----------------
         Nonoperating interests in oil and gas
              properties, using full cost accounting                                        4,235,685            4,226,916
         Less-Accumulated amortization                                                     (2,867,988)          (2,724,019)
                                                                                       ---------------     ----------------
                                                                                            1,367,697            1,502,897
                                                                                       ---------------     ----------------
                                                                                       $    1,426,814       $    1,574,816
                                                                                       ===============     ================


         LIABILITIES AND PARTNERS' CAPITAL:

         Current Liabilities:
              Payable related to excess costs                                          $        4,497       $        5,950
                                                                                       ---------------     ----------------

         Partners' Capital                                                                  1,422,317            1,568,866
                                                                                       ---------------     ----------------
                                                                                       $    1,426,814       $    1,574,816
                                                                                       ===============     ================
</TABLE>


                 See accompanying notes to financial statements.

                                        3


<PAGE>

                   SWIFT ENERGY PENSION PARTNERS 1991-C, 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         $        85,356   $       179,072  $       315,156   $       475,052
   Interest income                                        246               151              644               416
                                              ---------------   ---------------  ---------------   ---------------
                                                       85,602           179,223          315,800           475,468
                                              ---------------   ---------------  ---------------   ---------------

COSTS AND EXPENSES:
   Amortization                                        39,025            55,474          143,969           192,545
   General and administrative                          14,507            18,502           55,511            56,384
                                              ---------------   ---------------  ---------------   ---------------
                                                       53,532            73,976          199,480           248,929
                                              ---------------   ---------------  ---------------   ---------------
NET INCOME (LOSS)                             $        32,070   $       105,247  $       116,320   $       226,539
                                              ===============   ===============  ===============   ===============



Limited Partners' net income (loss)
   per unit                                   $           .01   $           .03  $           .03   $           .06
                                              ===============   ===============  ===============   ===============
</TABLE>


                 See accompanying notes to financial statements.

                                        4


<PAGE>

                   SWIFT ENERGY PENSION PARTNERS 1991-C, 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)                                                               $      116,320          $       226,539
    Adjustments to reconcile income (loss) to
      net cash provided by operations:
      Amortization                                                                     143,969                  192,545
      Change in assets and liabilities:
        (Increase) decrease in nonoperating interests income receivable                 12,847                  (65,235)
        Increase (decrease) in accounts payable
          and accrued liabilities                                                           --                  (95,683)
                                                                               ---------------          ---------------
               Net cash provided by (used in) operating activities                     273,136                  258,166
                                                                               ---------------          ---------------
CASH FLOWS FROM INVESTING ACTIVITIES:
    Additions to nonoperating interests in oil and gas properties                       (8,769)                 (79,139)
    Proceeds from sale of nonoperating interests
      in oil and gas properties                                                             --                    4,431
    Increase (decrease) in payabel related to excess costs                              (1,453)                      --
                                                                               ---------------          ---------------
               Net cash provided by (used in) investing activities                     (10,222)                 (74,708)
                                                                               ---------------          ---------------
CASH FLOWS FROM FINANCING ACTIVITIES:
    Cash distributions to partners                                                    (262,869)                (183,415)
                                                                               ---------------          ---------------
NET INCREASE (DECREASE) IN CASH AND CASH EQUIVALENTS                                        45                       43
                                                                               ---------------          ---------------
CASH AND CASH EQUIVALENTS AT BEGINNING OF PERIOD                                         1,505                    1,431
                                                                               ---------------          ---------------
CASH AND CASH EQUIVALENTS AT END OF PERIOD                                      $        1,550          $         1,474
                                                                               ===============          ===============
Supplemental disclosure of cash flow information:
    Cash paid during the period for interest                                    $           --          $        15,166
                                                                               ===============          ===============
</TABLE>



                 See accompanying notes to financial statements.

                                        5


<PAGE>

                   SWIFT ENERGY PENSION PARTNERS 1991-C, 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 Pension  Partners  1991-C,  Ltd., a Texas limited
        partnership  ("the  Partnership"),  was formed on December 30, 1991, for
        the purpose of  purchasing  net  profits  interest,  overriding  royalty
        interests and royalty interests (collectively, "nonoperating interests")
        in producing oil and gas properties within the continental United States
        and Canada. 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 sole limited partner of the Partnership is Swift Depositary Company,
        which has assigned all of its beneficial  (but not of record) rights and
        interest  as  limited  partner  to  the  investors  in  the  Partnership
        ("Interest  Holders"),   in  the  form  of  Swift  Depositary  Interests
        ("SDIs").

                  The Managing  General  Partner has paid or will pay out of its
        own corporate funds (as a capital  contribution to the  Partnership) all
        selling commissions,  offering expenses,  printing, legal and accounting
        fees and other  formation costs incurred in connection with the offering
        of SDIs and the  formation  of the  Partnership,  for which the Managing
        General  Partner  will  receive  an  interest  in  continuing  costs and
        revenues of the Partnership. The 350 Interest Holders made total capital
        contributions of $3,664,333.

                  Generally,   all  continuing  costs  (including   general  and
        administrative  reimbursements  and direct  expenses)  and  revenues are
        allocated  85  percent  to the  Interest  Holders  and 15 percent to the
        general  partners.   After   partnership   payout,  as  defined  in  the
        Partnership  Agreement,  continuing costs and revenues will be shared 75
        percent by the Interest Holders, and 25 percent by the general partners.

(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 PENSION PARTNERS 1991-C, 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 -

                  The  Partnership  entered  into a Net Profits  and  Overriding
        Royalty  Interest  Agreement  ("NP/OR   Agreement")  with  Swift  Energy
        Operating Partners 1991-C, Ltd. ("Operating Partnership"), an affiliated
        partnership  managed  by Swift  for the  purpose  of  acquiring  working
        interests in producing  oil and gas  properties.  Under the 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 the Partnership's  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 PENSION PARTNERS 1991-C, 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 PENSION PARTNERS 1991-C, LTD.
                MANAGEMENT'S DISCUSSION AND ANALYSIS OF FINANCIAL
                       CONDITION AND RESULTS OF OPERATIONS


GENERAL

      The  Partnership  was formed for the purpose of investing in  nonoperating
interests in producing oil and gas  properties  located  within the  continental
United States and Canada.  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  was  formed,  it  commenced  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 Interest Holders
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  was formed December 30, 1991, and effective at such date
expended all of the Interest  Holders' capital  contributions in the acquisition
of producing properties held in inventory by the Managing General Partner.

      The  Partnership  does  not  allow  for  additional  assessments  from the
partners or Interest Holders to fund capital  requirements.  However,  funds are
available  from  partnership  revenues or proceeds from the sale of  partnership
property.  The  Managing  General  Partner  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  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

      Income from  nonoperating  interests  decreased  52 percent in the current
quarter of 1997 when  compared to the third  quarter in 1996.  Oil and gas sales
declined  $108,559 or 44 percent in the third  quarter of 1997 when  compared to
the  corresponding  quarter  in 1996,  primarily  due to  decreased  gas and oil
production.  A decline  of 36 percent  in gas  production  and 20 percent in oil
production had a significant  impact on partnership  performance.  Also, current
quarter  oil prices  declined  27 percent or  $5.41/BBL  when  compared to third
quarter 1996 oil prices, further contributing to decreased revenues.

      Associated amortization expense decreased 30 percent or $16,449.


                                       9


<PAGE>

                   SWIFT ENERGY PENSION PARTNERS 1991-C, LTD.
                MANAGEMENT'S DISCUSSION AND ANALYSIS OF FINANCIAL
                 CONDITION AND RESULTS OF OPERATIONS (CONTINUED)


Nine Months Ended September 30, 1997 and 1996

      Income from  nonoperating  interests  decreased  34 percent in the current
period of 1997 when compared to the  corresponding  period in 1996.  Oil and gas
sales decreased $189,275 or 28 percent in the first nine months of 1997 over the
corresponding  period in 1996. A decline of 27 percent in gas  production and 20
percent in oil  production  were  major  contributing  factors to the  decreased
revenues for the period.  Decreased oil prices of 8 percent or $1.36/BBL further
contributed to the decreased revenues.

      Associated amortization expense declined 25 percent or $48,576.

      During 1997,  partnership  revenues  and costs will be shared  between the
Interest Holders and general partners in an 85:15 ratio.


                                       10


<PAGE>

                   SWIFT ENERGY PENSION PARTNERS 1991-C, 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 PENSION
                                        PARTNERS 1991-C, 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