<ARTICLE> 5
<MULTIPLIER> 1,000
       
                             
<PERIOD-TYPE>                   3-MOS
<FISCAL-YEAR-END>                          DEC-31-1998
<PERIOD-START>                             JAN-01-1998
<PERIOD-END>                               MAR-31-1998
<CASH>                                          24,924
<SECURITIES>                                         0
<RECEIVABLES>                                   85,390
<ALLOWANCES>                                         0
<INVENTORY>                                          0
<CURRENT-ASSETS>                               140,221
<PP&E>                                         726,244
<DEPRECIATION>                                 185,141
<TOTAL-ASSETS>                                 681,324
<CURRENT-LIABILITIES>                           82,023
<BONDS>                                              0
<PREFERRED-MANDATORY>                                0
<PREFERRED>                                          0
<COMMON>                                           387
<OTHER-SE>                                     405,767
<TOTAL-LIABILITY-AND-EQUITY>                   681,324
<SALES>                                        199,707
<TOTAL-REVENUES>                               199,707
<CGS>                                                0
<TOTAL-COSTS>                                  181,564
<OTHER-EXPENSES>                                 (400)
<LOSS-PROVISION>                                     0
<INTEREST-EXPENSE>                               1,006
<INCOME-PRETAX>                                 17,537
<INCOME-TAX>                                     6,664
<INCOME-CONTINUING>                             10,873
<DISCONTINUED>                                       0
<EXTRAORDINARY>                                      0
<CHANGES>                                            0
<NET-INCOME>                                    10,873
<EPS-PRIMARY>                                      .28
<EPS-DILUTED>                                      .28