<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 March 31, 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 0-17023


                    SWIFT ENERGY INCOME PARTNERS 1986-D, LTD.
             (Exact name of registrant as specified in its charter)

<TABLE>
<S>                                           <C>
                  Texas                                   76-0208087
(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 1986-D, LTD.

                                      INDEX



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

            Balance Sheets

                - March 31, 1997 and December 31, 1996                 3

            Statements of Operations

                - Three month periods ended March 31, 1997 and 1996    4

            Statements of Cash Flows

                - Three month periods ended March 31, 1997 and 1996    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                                          8


SIGNATURES                                                             9
</TABLE>


<PAGE>

                    SWIFT ENERGY INCOME PARTNERS 1986-D, LTD.
                                 BALANCE SHEETS



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

         Current Assets:
              Cash and cash equivalents                                                $       29,111       $        1,029
              Oil and gas sales receivable                                                    231,762              199,066
              Receivable due to property disposition                                               --              105,380
                                                                                       ---------------      ---------------
                   Total Current Assets                                                       260,873              305,475
                                                                                       ---------------      ---------------

         Oil and Gas Properties, using full cost
              accounting                                                                   12,903,273           12,897,927
         Less-Accumulated depreciation, depletion
              and amortization                                                            (10,569,011)         (10,534,127)
                                                                                       ---------------      ---------------
                                                                                            2,334,262            2,363,800
                                                                                       ---------------      ---------------
                                                                                       $    2,595,135       $    2,669,275
                                                                                       ===============      ===============

         LIABILITIES AND PARTNERS' CAPITAL:

         Current Liabilities:
             Accounts payable and accrued liabilities                                  $       79,652       $      105,215
                                                                                       ---------------      ---------------

         Deferred Revenues                                                                    126,311              126,636

         Partners' Capital                                                                  2,389,172            2,437,424
                                                                                       ---------------      ---------------
                                                                                       $    2,595,135       $    2,669,275
                                                                                       ===============      ===============
</TABLE>


                 See accompanying notes to financial statements.

                                        3


<PAGE>

                    SWIFT ENERGY INCOME PARTNERS 1986-D, LTD.
                            STATEMENTS OF OPERATIONS
                                   (Unaudited)


<TABLE>
<CAPTION>
                                                                                         Three Months Ended
                                                                                              March 31,
                                                                                 ---------------------------------
                                                                                      1997                   1996
                                                                                 ---------------   ---------------
         <S>                                                                     <C>               <C>            
         REVENUES:
             Oil and gas sales                                                   $       154,519   $       313,192
             Interest income                                                                 429               433
             Other                                                                         1,394             1,677
                                                                                 ---------------   ---------------
                                                                                         156,342           315,302
                                                                                 ---------------   ---------------
         COSTS AND EXPENSES:
             Lease operating                                                              48,622            87,717
             Production taxes                                                              7,935             9,698
             Depreciation, depletion
               and amortization                                                           34,884            76,045
             General and administrative                                                   32,596            31,169
             Interest expense                                                                 --             8,159
                                                                                 ---------------   ---------------
                                                                                         124,037           212,788
                                                                                 ---------------   ---------------
         NET INCOME (LOSS)                                                       $        32,305   $       102,514
                                                                                 ===============   ===============
</TABLE>


         Limited Partners' net income (loss)
             per unit

         March 31, 1997                       $          2.29
                                              ===============
         March 31, 1996                       $          7.26
                                              ===============


                 See accompanying note to financial statements.

                                        4


<PAGE>

                    SWIFT ENERGY INCOME PARTNERS 1986-D, LTD.
                            STATEMENTS OF CASH FLOWS
                                   (Unaudited)

<TABLE>
<CAPTION>
                                                                                           Three Months Ended
                                                                                                March 31,
                                                                               ----------------------------------------
                                                                                       1997                    1996
                                                                               ---------------          ---------------
<S>                                                                             <C>                     <C>            
CASH FLOWS FROM OPERATING ACTIVITIES:
    Income (loss)                                                               $       32,305          $       102,514
    Adjustments to reconcile income (loss) to
      net cash provided by operations:
      Depreciation, depletion and amortization                                          34,884                   76,045
      Change in gas imbalance receivable
          and deferred revenues                                                           (325)                  (1,327)
      Change in assets and liabilities:
        (Increase) decrease in oil and gas sales receivable                            (32,696)                 (93,791)
        (Increase) decrease in other current assets                                    105,380                       --
        Increase (decrease) in accounts payable
          and accrued liabilities                                                      (25,563)                 (32,166)
                                                                               ---------------          ---------------
                Net cash provided by (used in) operating activities                    113,985                   51,275
                                                                               ---------------          ---------------
CASH FLOWS FROM INVESTING ACTIVITIES:
    Additions to oil and gas properties                                                 (5,346)                  (6,361)
                                                                               ---------------          ---------------
CASH FLOWS FROM FINANCING ACTIVITIES:
    Cash distributions to partners                                                     (80,557)                 (19,834)
    Payment on notes payable                                                                --                  (25,000)
                                                                               ---------------          ---------------
                Net cash provided by (used in) financing activities                    (80,557)                 (44,834)
                                                                               ---------------          ---------------
NET INCREASE (DECREASE) IN CASH AND CASH EQUIVALENTS                                    28,082                       80
                                                                               ---------------          ---------------
CASH AND CASH EQUIVALENTS AT BEGINNING OF PERIOD                                         1,029                    1,854
                                                                               ---------------          ---------------
CASH AND CASH EQUIVALENTS AT END OF PERIOD                                      $       29,111          $         1,934
                                                                               ===============          ===============
Supplemental disclosure of cash flow information:
    Cash paid during the period for interest                                    $           --          $         8,787
                                                                               ===============          ===============
</TABLE>


                 See accompanying notes to financial statements.

                                        5


<PAGE>

                    SWIFT ENERGY INCOME PARTNERS 1986-D, 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)  Gas Imbalances -

                  The  gas  imbalance   receivable  and  deferred  revenues  are
        accounted  for on  the  entitlements  method,  whereby  the  Partnership
        records its share of revenue,  based on its entitled amount. Any amounts
        over or under  the  entitled  amount  are  recorded  as an  increase  or
        decrease  to the  gas  imbalance  receivable  or  deferred  revenues  as
        applicable.

(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.

                  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.

(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 1986-D, 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  results 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

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

      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  Partner  believes  that the  funds  currently
available to the Partnership  will be adequate to meet any  anticipated  capital
requirements.

Results of Operations

      Oil and gas sales  declined  51 percent in the first  quarter of 1997 when
compared  to the same period in 1996,  primarily  due to  decreased  gas and oil
production.  Gas production  decreased 43 percent and oil production declined 51
percent.  The decrease in  production  had a significant  impact on  partnership
performance.  Production  declines were  partially  offset by an increase in gas
prices of 63 percent,  or $1.24/MCF  and in oil prices of 8 percent or $1.47/BBL
when compared to first quarter 1996 prices.

      Also, current quarter oil and gas sales decreased due to the settlement of
pending  litigation on the Kaiser Francis I acquisition,  Cassel 1-17 well. Take
or pay  proceeds  were  received in the amount of $119,150  and  recorded in the
March 1996 revenues.

      Associated depreciation expense decreased 54 percent or $41,161.

      The Partnership records an additional provision in depreciation, depletion
and amortization 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 March 31, 1997, the Partnership  would have recorded an additional  provision
at March 31, 1997 in the amount of  $162,964.  However,  these  temporarily  low
quarter-end  prices  rebounded and by using prices in effect at the filing date,
the Partnership's unamortized cost of oil and gas properties were not limited by
this calculation

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


                                       7


<PAGE>

                    SWIFT ENERGY INCOME PARTNERS 1986-D, LTD.
                           PART II - OTHER INFORMATION




ITEM 5.    OTHER INFORMATION


                                     -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.


                                                SWIFT ENERGY INCOME
                                                PARTNERS 1986-D, LTD.
                                                (Registrant)

                                     By:        SWIFT ENERGY COMPANY
                                                Managing General Partner


Date:     May 5, 1997                By:        /s/ John R. Alden
          -----------                           --------------------------------
                                                John R. Alden
                                                Senior Vice President, Secretary
                                                and Principal Financial Officer

Date:     May 5, 1997                By:        /s/ Alton D. Heckaman, Jr.
          -----------                           --------------------------------
                                                Alton D. Heckaman, Jr.
                                                Vice President, Controller
                                                and Principal Accounting Officer


                                        9