<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, 1996

                                       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)

                                  (713)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>
<S>                                                                                                             <C>
PART I.    FINANCIAL INFORMATION                                                                               PAGE


      ITEM 1.    Financial Statements

            Balance Sheets

                - September 30, 1996 and December 31, 1995                                                         3

            Statements of Operations

                - Three month and nine month periods ended September 30, 1996 and 1995                             4

            Statements of Cash Flows

                - Nine month periods ended September 30, 1996 and 1995                                             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 1986-D, LTD.
                                 BALANCE SHEETS


<TABLE>
<CAPTION>
                                                                                           September 30,        December 31,
                                                                                               1996                 1995
                                                                                      -------------------  -----------------
                                                                                            (Unaudited)
         <S>                                                                           <C>                  <C>           

         ASSETS:

         Current Assets:
              Cash and cash equivalents                                                $        1,000       $        1,854
              Oil and gas sales receivable                                                     184,431              212,786
                                                                                       ---------------      ---------------
                   Total Current Assets                                                       185,431              214,640
                                                                                       ---------------      ---------------

         Gas Imbalance Receivable                                                                  --                5,085
                                                                                       ---------------      ---------------

         Oil and Gas Properties, using full cost
              accounting                                                                   12,954,592           13,172,466
         Less-Accumulated depreciation, depletion
              and amortization                                                            (10,484,114)         (10,310,097)
                                                                                       ---------------      ---------------
                                                                                            2,470,478            2,862,369
                                                                                       ---------------      ---------------
                                                                                       $    2,655,909       $    3,082,094
                                                                                       ===============      ===============

         LIABILITIES AND PARTNERS' CAPITAL:

         Current Liabilities:
             Accounts payable and accrued liabilities                                  $       97,449       $      591,027
             Current portion of note payable                                                       --               25,000
                                                                                       ---------------      ---------------
                   Total Current Liabilities                                                   97,449              616,027
                                                                                       ---------------      ---------------

         Deferred Revenues                                                                    124,564              146,384

         Partners' Capital                                                                  2,433,896            2,319,683
                                                                                       ---------------      ---------------
                                                                                       $    2,655,909       $    3,082,094
                                                                                       ===============      ===============
</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                 Nine Months Ended
                                                         September 30,                     September 30,
                                              ---------------------------------  ---------------------------------
                                                    1996              1995             1996             1995
                                              ---------------   ---------------  ---------------  ----------------
<S>                                           <C>               <C>              <C>               <C>            
REVENUES:
   Oil and gas sales                          $       189,221   $       118,103  $       693,732   $       536,527
   Interest income                                        500                46            1,419               133
   Other                                                3,243             2,019           11,430             7,416
                                              ---------------   ---------------  ---------------   ---------------
                                                      192,964           120,168          706,581           544,076
                                              ---------------   ---------------  ---------------   ---------------

COSTS AND EXPENSES:
   Lease operating                                     54,550            61,713          189,486           234,382
   Production taxes                                     8,788             6,009           27,809            29,483
   Depreciation, depletion
      and amortization -
        Normal provision                               45,946            39,003          174,017           195,064
        Additional provision                               --            64,306               --           525,447
   General and administrative                          25,772            21,581           87,757            65,096
   Interest expense                                       128            10,841           11,417            30,492
                                              ---------------   ---------------  ---------------   ---------------
                                                      135,184           203,453          490,486         1,079,964
                                              ---------------   ---------------  ---------------   ---------------
NET INCOME (LOSS)                             $        57,780   $       (83,285) $       216,095   $      (535,888)
                                              ===============   ===============  ===============   ===============



Limited Partners' net income (loss)
   per unit                                   $          4.09   $         (5.90) $         15.30   $        (37.95)
                                              ===============   ===============  ===============   ===============
</TABLE>



                 See accompanying note to financial statements.

                                        4

<PAGE>


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

<TABLE>
<CAPTION>
                                                                                           Nine Months Ended
                                                                                             September 30,
                                                                               ----------------------------------------
                                                                                        1996                   1995
                                                                               ----------------      ------------------
<S>                                                                             <C>                     <C>             
CASH FLOWS FROM OPERATING ACTIVITIES:
    Income (Loss)                                                               $      216,095          $      (535,888)
    Adjustments to reconcile income (loss) to
      net cash provided by operations:
      Depreciation, depletion and amortization                                         174,017                  720,511
      Change in gas imbalance receivable
         and deferred revenues                                                         (16,735)                   2,118
      Change in assets and liabilities:
        (Increase) decrease in oil and gas sales receivable                             28,355                  111,340
        Increase (decrease) in accounts payable
          and accrued liabilities                                                     (493,578)                  17,856
                                                                               ---------------          ---------------
               Net cash provided by (used in) operating activities                     (91,846)                 315,937
                                                                               ---------------          ---------------
CASH FLOWS FROM INVESTING ACTIVITIES:
    Additions to oil and gas properties                                                (28,709)                (100,441)
    Proceeds from sales of oil and gas properties                                      246,583                   23,256
                                                                               ---------------          ---------------
               Net cash provided by (used in) investing activities                     217,874                  (77,185)
                                                                               ---------------          ---------------
CASH FLOWS FROM FINANCING ACTIVITIES:
    Cash distributions to partners                                                    (101,882)                (163,474)
    Payments on note payable                                                           (25,000)                 (75,000)
                                                                               ---------------          ---------------

                    Net cash provided by (used in) financing activities               (126,882)                (238,474)
                                                                               ---------------          ---------------
NET INCREASE (DECREASE) IN CASH AND CASH EQUIVALENTS                                      (854)                     278
                                                                               ---------------          ---------------
CASH AND CASH EQUIVALENTS AT BEGINNING OF PERIOD                                         1,854                    1,468
                                                                               ---------------          ---------------
CASH AND CASH EQUIVALENTS AT END OF PERIOD                                      $        1,000          $         1,746
                                                                               ===============          ===============
Supplemental disclosure of cash flow information:
    Cash paid during the period for interest                                    $       12,045          $         7,355
                                                                               ===============          ===============
</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,  1995  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  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.

(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 the limited  partners'  commitments  available for
property acquisitions.

      The  Partnership  does  not  allow  for  additional  assessments  from the
partners  to fund  capital  requirements.  However,  funds  in  addition  to the
remaining  unexpended net capital commitments of the partners 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

      The  following  analysis  explains  changes  in the  revenue  and  expense
categories  for the quarter  ended  September  30, 1996  (current  quarter) when
compared to the quarter ended September 30, 1995  (corresponding  quarter),  and
for the nine months ended September 30, 1996 (current period),  when compared to
the nine months ended September 30, 1995 (corresponding period).

Three Months Ended September 30, 1996 and 1995

      Oil and gas sales  increased  $71,118 or 60 percent in the current quarter
of 1996 when  compared to the  corresponding  quarter in 1995,  primarily due to
increased  gas and oil  prices.  An  increase  in gas  prices of 47  percent  or
$.71/MCF and in oil prices of 35 percent or $5.27/BBL had a  significant  impact
on partnership  performance.  Also, current quarter gas production  increased 18
percent  when  compared  to  third  quarter  1995  production  volumes,  further
contributing to increased revenues.

      Associated depreciation expense increased 18 percent or $6,943.

      The  Partnership   recorded  an  additional   provision  in  depreciation,
depletion  and  amortization  in the third  quarter of 1995 for $64,306 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.

                                       7
<PAGE>

                   SWIFT ENERGY INCOME PARTNERS 1986-D, LTD.
               MANAGEMENT'S DISCUSSION AND ANALYSIS OF FINANCIAL
                CONDITION AND RESULTS OF OPERATIONS (CONTINUED)


Nine Months Ended September 30, 1996 and 1995

      Oil and gas sales  increased  $157,206  or 29  percent  in the first  nine
months of 1996 over the corresponding  period in 1995. An increase in gas prices
of 42 percent or  $.62/MCF  and in oil  prices of 21 percent or  $3.30/BBL  were
major  contributing  factors to the  increased  revenues  for the period.  Also,
current  period gas and oil  production  decreased  20 percent  and 20  percent,
respectively,  when  compared  to the  corresponding  period in 1995,  partially
offsetting the effect of increased gas and oil prices.

      Associated depreciation expense decreased 11 percent or $21,047.

      The  Partnership   recorded  an  additional   provision  in  depreciation,
depletion  and  amortization  in the first nine months of 1995 for $525,447 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 Exchange Commission.

      During 1996,  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 1986-D, 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 1986-D, LTD.
                                                (Registrant)

                                     By:        SWIFT ENERGY COMPANY
                                                Managing General Partner


Date:  November 6, 1996              By:        /s/ John R. Alden
       ----------------                         --------------------------------
                                                John R. Alden
                                                Senior Vice President, Secretary
                                                and Principal Financial Officer

Date:  November 6, 1996              By:        /s/ Alton D. Heckaman, Jr.
       ----------------                         --------------------------------
                                                Alton D. Heckaman, Jr.
                                                Vice President, Controller
                                                and Principal Accounting Officer

                                       10