<TABLE> <S> <C>

<PAGE>
 
<ARTICLE> 5
<LEGEND>
THIS SCHEDULE CONTAINS SUMMARY FINANCIAL INFORMATION EXTRACTED FROM FORM 10-Q
QUARTERLY REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITY EXCHANGE ACT OF
1934 FOR THE QUARTERLY PERIOD ENDED SEPTEMBER 30, 1998 AND IS QUALIFIED IN ITS
ENTIRETY BY REFERENCE TO SUCH FINANCIAL STATEMENTS.
</LEGEND>
<MULTIPLIER> 1,000
       
<S>                             <C>                     <C>
<PERIOD-TYPE>                   3-MOS                   9-MOS
<FISCAL-YEAR-END>                          DEC-31-1998             DEC-31-1998
<PERIOD-START>                             JUL-01-1998             JAN-01-1998
<PERIOD-END>                               SEP-30-1998             SEP-30-1998
<CASH>                                           7,487                   7,487
<SECURITIES>                                         0                       0
<RECEIVABLES>                                    3,560                   3,560
<ALLOWANCES>                                      (50)                    (50)
<INVENTORY>                                          0                       0
<CURRENT-ASSETS>                                11,324                  11,324
<PP&E>                                         226,919                 226,919
<DEPRECIATION>                               (114,003)               (114,003)
<TOTAL-ASSETS>                                 124,418                 124,418
<CURRENT-LIABILITIES>                            8,797                   8,797
<BONDS>                                              0                       0
<PREFERRED-MANDATORY>                                0                       0
<PREFERRED>                                          0                       0
<COMMON>                                            87                      87
<OTHER-SE>                                      62,628                  62,628
<TOTAL-LIABILITY-AND-EQUITY>                   124,418                 124,418
<SALES>                                          5,827                  17,717
<TOTAL-REVENUES>                                 6,173                  18,764
<CGS>                                                0                       0
<TOTAL-COSTS>                                    7,279                  21,318
<OTHER-EXPENSES>                                  (38)                       1
<LOSS-PROVISION>                                     0                       0
<INTEREST-EXPENSE>                                 937                   2,676
<INCOME-PRETAX>                                (1,336)                 (4,386)
<INCOME-TAX>                                     (572)                 (1,957)
<INCOME-CONTINUING>                                  0                       0
<DISCONTINUED>                                       0                       0
<EXTRAORDINARY>                                      0                       0
<CHANGES>                                            0                       0
<NET-INCOME>                                     (764)                 (2,429)
<EPS-PRIMARY>                                   (0.09)                  (0.28)
<EPS-DILUTED>                                   (0.09)                  (0.28)
        

</TABLE>