<ARTICLE>                     5
<LEGEND>
This schedule contains summary financial information extracted from Swift Energy
Income  Partners  1986-D,  Ltd.'s balance sheet and statement of operations con-
tained in its Form 10-Q for the quarter  ended June 30, 1998 and is qualified in
its entirety by reference to such financial statements.
</LEGEND>
       
                             
<PERIOD-TYPE>                   6-MOS
<FISCAL-YEAR-END>                              DEC-31-1998
<PERIOD-END>                                   JUN-30-1998
<CASH>                                         1,000
<SECURITIES>                                   0
<RECEIVABLES>                                  195,320
<ALLOWANCES>                                   0
<INVENTORY>                                    0
<CURRENT-ASSETS>                               205,343
<PP&E>                                         12,804,053
<DEPRECIATION>                                 (10,746,131)
<TOTAL-ASSETS>                                 2,263,611
<CURRENT-LIABILITIES>                          57,318
<BONDS>                                        0
<PREFERRED-MANDATORY>                          0
<PREFERRED>                                    0
<COMMON>                                       0
<OTHER-SE>                                     2,097,006
<TOTAL-LIABILITY-AND-EQUITY>                   2,263,611
<SALES>                                        133,377
<TOTAL-REVENUES>                               138,056
<CGS>                                          0
<TOTAL-COSTS>                                  152,791<F1>
<OTHER-EXPENSES>                               0
<LOSS-PROVISION>                               0
<INTEREST-EXPENSE>                             0
<INCOME-PRETAX>                                (78,307)
<INCOME-TAX>                                   0
<INCOME-CONTINUING>                            (78,307)
<DISCONTINUED>                                 0
<EXTRAORDINARY>                                0
<CHANGES>                                      0
<NET-INCOME>                                   (78,307)
<EPS-PRIMARY>                                  0
<EPS-DILUTED>                                  0
<FN>
<F1>Includes  lease  operating  expenses,  production  taxes  and  depreciation,
depletion and  amortization  expense.  Excludes general and  administrative  and
interest expense.
</FN>