<ARTICLE> 5
<LEGEND>
THIS SCHEDULE CONTAINS SUMMARY FINANCIAL INFORMATION EXTRACTED FROM THE
COMPANY'S FINANCIAL STATEMENTS AND IS QUALIFIED IN ITS ENTIRETY BY REFERENCE TO
SUCH FINANCIAL STATEMENTS.
</LEGEND>
<RESTATED> 
<MULTIPLIER> 1,000
       
                                                                                                  
<PERIOD-TYPE>                         3-MOS                   6-MOS                   9-MOS                   YEAR
<FISCAL-YEAR-END>                          DEC-31-1996             DEC-31-1996             DEC-31-1996             DEC-31-1996
<PERIOD-END>                               MAR-31-1996             JUN-30-1996             SEP-30-1996             DEC-31-1996
<CASH>                                           3,867                   5,051                  11,357                  28,180
<SECURITIES>                                     5,110                   5,202                   6,827                       0
<RECEIVABLES>                                   87,624                 144,812                 135,008                 172,214
<ALLOWANCES>                                         0                       0                       0                       0
<INVENTORY>                                     15,746                  31,085                  30,678                  30,407
<CURRENT-ASSETS>                               120,556                 201,355                 195,330                 242,967
<PP&E>                                         761,834               1,320,319               1,390,839               1,471,085
<DEPRECIATION>                                 228,189                 243,426                 262,186                 272,925
<TOTAL-ASSETS>                                 658,185               1,367,329               1,414,019               1,574,500
<CURRENT-LIABILITIES>                           50,076                  74,807                  81,547                 128,000
<BONDS>                                         15,000                  70,000                  55,000                  63,000
<PREFERRED-MANDATORY>                                0                       0                       0                       0
<PREFERRED>                                          0                       0                       0                       0
<COMMON>                                           500                     683                     683                     684
<OTHER-SE>                                     511,132               1,098,237               1,136,651               1,194,048
<TOTAL-LIABILITY-AND-EQUITY>                   658,185               1,367,329               1,414,019               1,574,500
<SALES>                                              0                       0                       0                       0
<TOTAL-REVENUES>                               106,868                 253,851                 424,473                 611,430
<CGS>                                                0                       0                       0                       0
<TOTAL-COSTS>                                   66,157<F1>             147,754<F1>             242,109<F1>             341,654<F1>
<OTHER-EXPENSES>                                15,015<F2>              33,787<F2>              52,534<F2>              56,285<F2>
<LOSS-PROVISION>                                     0                       0                       0                       0
<INTEREST-EXPENSE>                                   0                     104                     104                   2,326
<INCOME-PRETAX>                                 26,130                  72,914                 130,843                 212,705
<INCOME-TAX>                                     7,398                  21,160                  40,609                  66,317
<INCOME-CONTINUING>                             18,732                  51,754                  90,234                 146,388
<DISCONTINUED>                                       0                       0                       0                       0
<EXTRAORDINARY>                                      0                       0                       0                       0
<CHANGES>                                            0                       0                       0                       0
<NET-INCOME>                                    18,732                  51,754                  90,234                 146,388
<EPS-PRIMARY>                                     0.19<F3>                0.46<F3>                0.75<F3>                1.18<F3>
<EPS-DILUTED>                                     0.19<F3>                0.46<F3>                0.75<F3>                1.18<F3>
<FN>
<F1>Includes contract drilling expenses only.
<F2>Includes other operating expenses.
<F3>Per share amounts reflect the retroactive effect of the two-for-one stock split
in the form of a stock dividend to stockholders of record on July 24, 1997.
</FN>