NOBLE DRILLING CORP
10-Q, 1998-11-16
DRILLING OIL & GAS WELLS
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<PAGE>   1
===============================================================================




                                  UNITED STATES
                       SECURITIES AND EXCHANGE COMMISSION
                             WASHINGTON, D.C. 20549

                                    FORM 10-Q

             [X] QUARTERLY REPORT PURSUANT TO SECTION 13 OR 15(d) OF
                       THE SECURITIES EXCHANGE ACT OF 1934
                For the quarterly period ended September 30, 1998

                                       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: 0-13857


                           NOBLE DRILLING CORPORATION
             (Exact name of registrant as specified in its charter)


                DELAWARE                              73-0374541
        (State of incorporation)        (I.R.S. employer identification number)


    10370 RICHMOND AVENUE, SUITE 400                     77042
             HOUSTON, TEXAS                           (Zip code)
(Address of principal executive offices)


       REGISTRANT'S TELEPHONE NUMBER, INCLUDING AREA CODE: (713) 974-3131


         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 [ ]

               Number of shares of Common Stock outstanding as of
                         November 6, 1998: 131,077,729


===============================================================================

<PAGE>   2



                   NOBLE DRILLING CORPORATION AND SUBSIDIARIES
                      CONDENSED CONSOLIDATED BALANCE SHEETS
                     (In thousands, except par value amount)
                                   (Unaudited)

<TABLE>
<CAPTION>

                                                                            SEPTEMBER 30,     DECEMBER 31,
                                                                               1998              1997
                                                                           ------------      ------------
<S>                                                                        <C>               <C>         
ASSETS
CURRENT ASSETS
  Cash and cash equivalents ..........................................     $     43,115      $     49,917
  Investment in marketable debt securities ...........................               --            16,471
  Accounts receivable (net allowance of $509 and $1,380) .............          139,434           135,716
  Costs of uncompleted contracts in excess of billings ...............            6,115               941
  Inventories ........................................................            5,206             4,559
  Deferred income taxes ..............................................               97               391
  Prepaid expenses ...................................................           25,867            21,569
  Other current assets ...............................................           37,279            35,451
                                                                           ------------      ------------
Total current assets .................................................          257,113           265,015
                                                                           ------------      ------------

PROPERTY AND EQUIPMENT
  Drilling equipment and facilities ..................................        1,829,972         1,414,714
  Other ..............................................................           29,366            24,287
                                                                           ------------      ------------
                                                                              1,859,338         1,439,001
  Accumulated depreciation ...........................................         (305,476)         (254,388)
                                                                           ------------      ------------
                                                                              1,553,862         1,184,613
                                                                           ------------      ------------
INVESTMENTS IN AND ADVANCES TO JOINT VENTURES ........................           49,216            21,097
DEFERRED INCOME TAXES ................................................            4,169             5,947

OTHER ASSETS .........................................................           33,255            29,139
                                                                           ------------      ------------
                                                                           $  1,897,615      $  1,505,811
                                                                           ============      ============
LIABILITIES AND SHAREHOLDERS' EQUITY
CURRENT LIABILITIES
  Short-term debt and current installments of long-term debt .........     $     86,842      $      9,698
  Accounts payable ...................................................           92,136            77,366
  Accrued payroll and related costs ..................................           25,386            25,858
  Taxes payable ......................................................           38,081            23,708
  Interest payable ...................................................            2,153             6,088
  Other current liabilities ..........................................           34,500            10,172
                                                                           ------------      ------------
Total current liabilities ............................................          279,098           152,890

LONG-TERM DEBT .......................................................          262,167           138,139
DEFERRED INCOME TAXES ................................................           74,232            63,946
OTHER LIABILITIES ....................................................            2,672             1,782
                                                                           ------------      ------------
                                                                                618,169           356,757
                                                                           ------------      ------------
SHAREHOLDERS' EQUITY
  Common stock, $0.10 par value ......................................           13,369            13,334
  Capital in excess of par value .....................................          941,985           934,383
  Retained earnings ..................................................          385,241           255,992
  Treasury stock, at cost ............................................          (60,222)          (53,544)
  Accumulated other comprehensive income .............................             (927)           (1,111)
                                                                           ------------      ------------
                                                                              1,279,446         1,149,054
                                                                           ------------      ------------
COMMITMENTS AND CONTINGENCIES ........................................               --                --
                                                                           ============      ============
                                                                           $  1,897,615      $  1,505,811
                                                                           ============      ============
</TABLE>



   See accompanying notes to the condensed consolidated financial statements.




                                       2

<PAGE>   3


                   NOBLE DRILLING CORPORATION AND SUBSIDIARIES
                 CONDENSED CONSOLIDATED STATEMENTS OF OPERATIONS
                    (In thousands, except per share amounts)
                                   (Unaudited)


<TABLE>
<CAPTION>

                                                        THREE MONTHS ENDED SEPTEMBER 30,
                                                       ----------------------------------
                                                           1998                1997
                                                       --------------      --------------
<S>                                                    <C>                 <C>           

OPERATING REVENUES
   Contract drilling services ....................     $      145,169      $      111,569
   Labor contract drilling services ..............             15,238              14,910
   Turnkey drilling services .....................             32,869              41,086
   Engineering and consulting services ...........                260                 540
   Other revenue .................................              1,513               3,531
                                                       --------------      --------------
                                                              195,049             171,636
                                                       --------------      --------------
OPERATING COSTS AND EXPENSES
   Contract drilling services ....................             60,534              39,000
   Labor contract drilling services ..............             11,767               9,958
   Turnkey drilling services .....................             37,105              41,171
   Engineering and consulting services ...........                600                 141
   Other expense .................................              1,029               1,009
   Depreciation and amortization .................             17,940              18,674
   Selling, general and administrative ...........             17,673              18,036
                                                       --------------      --------------
                                                              146,648             127,989
                                                       --------------      --------------

OPERATING INCOME .................................             48,401              43,647

OTHER INCOME (EXPENSE)
   Interest expense ..............................             (1,160)             (1,595)
   Interest income ...............................              1,842               2,621
   Other, net ....................................             (1,910)                 28
                                                       --------------      --------------

INCOME BEFORE INCOME TAXES .......................             47,173              44,701

INCOME TAX PROVISION .............................            (14,557)            (11,220)
                                                       --------------      --------------

NET INCOME .......................................     $       32,616      $       33,481
                                                       ==============      ==============

EARNINGS PER SHARE-BASIC .........................     $         0.25      $         0.25
                                                       ==============      ==============

EARNINGS PER SHARE-DILUTED .......................     $         0.25      $         0.25
                                                       ==============      ==============
</TABLE>



   See accompanying notes to the condensed consolidated financial statements.


                                       3

<PAGE>   4



                   NOBLE DRILLING CORPORATION AND SUBSIDIARIES
                 CONDENSED CONSOLIDATED STATEMENTS OF OPERATIONS
                    (In thousands, except per share amounts)
                                   (Unaudited)

<TABLE>
<CAPTION>

                                                                   NINE MONTHS ENDED SEPTEMBER 30,
                                                                 ----------------------------------
                                                                      1998                1997
                                                                 --------------      --------------
<S>                                                              <C>                 <C>           
OPERATING REVENUES
   Contract drilling services ..............................     $      450,740      $      339,768
   Labor contract drilling services ........................             49,772              34,133
   Turnkey drilling services ...............................             92,717             140,087
   Engineering and consulting services .....................              1,466               1,894
   Other revenue ...........................................              5,618               9,461
                                                                 --------------      --------------
                                                                        600,313             525,343
                                                                 --------------      --------------
OPERATING COSTS AND EXPENSES
   Contract drilling services ..............................            175,114             132,687
   Labor contract drilling services ........................             36,186              23,527
   Turnkey drilling services ...............................             91,594             135,087
   Engineering and consulting services .....................              1,669               1,373
   Other expense ...........................................              3,035               3,184
   Depreciation and amortization ...........................             53,811              55,556
   Selling, general and administrative .....................             53,883              49,514
   Gains on sales of property and equipment ................                 --            (197,676)
   Minority interest .......................................                 --                 505
                                                                 --------------      --------------
                                                                        415,292             203,757
                                                                 --------------      --------------

OPERATING INCOME ...........................................            185,021             321,586

OTHER INCOME (EXPENSE)
   Interest expense ........................................             (3,402)            (11,690)
   Interest income .........................................              4,919               7,670
   Other, net ..............................................               (104)              1,567
                                                                 --------------      --------------


INCOME BEFORE INCOME TAXES AND EXTRAORDINARY CHARGE ........            186,434             319,133

INCOME TAX PROVISION .......................................            (57,185)           (100,304)
                                                                 --------------      --------------

INCOME BEFORE EXTRAORDINARY CHARGE .........................            129,249             218,829

EXTRAORDINARY CHARGE, NET OF TAX ...........................                 --              (6,685)
                                                                 --------------      --------------

NET INCOME .................................................     $      129,249      $      212,144
                                                                 ==============      ==============

EARNINGS PER SHARE-BASIC:
  Income before extraordinary charge .......................     $         0.99      $         1.66
  Extraordinary charge .....................................                 --               (0.05)
                                                                 --------------      --------------
  Net income per common share ..............................     $         0.99      $         1.61
                                                                 ==============      ==============

EARNINGS PER SHARE-DILUTED:
  Income before extraordinary charge .......................     $         0.98      $         1.64
  Extraordinary charge .....................................                 --               (0.05)
                                                                 --------------      --------------
  Net income per common share ..............................     $         0.98      $         1.59
                                                                 ==============      ==============
</TABLE>


   See accompanying notes to the condensed consolidated financial statements.


                                       4

<PAGE>   5
                   NOBLE DRILLING CORPORATION AND SUBSIDIARIES
            CONDENSED CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME
                                 (In thousands)
                                   (Unaudited)

<TABLE>
<CAPTION>

                                                                         THREE MONTHS ENDED SEPTEMBER 30,
                                                                          ------------------------------
                                                                             1998          1997
                                                                            --------     --------
<S>                                                                         <C>          <C>     
NET INCOME ............................................................     $ 32,616     $ 33,481
                                                                            --------     --------

OTHER COMPREHENSIVE INCOME (LOSS), NET OF TAX:
   Foreign currency translation adjustments ...........................          256         (461)
                                                                            --------     --------
   Unrealized gains on securities:
     Unrealized holding gains arising during period ...................         --             15
     Less: reclassification adjustment for gains realized in net income         --           --
                                                                            --------     --------
     Net unrealized gains .............................................         --             15
                                                                            --------     --------
   Other comprehensive income (loss) ..................................          256         (446)
                                                                            --------     --------

COMPREHENSIVE INCOME ..................................................     $ 32,872     $ 33,035
                                                                            ========     ========

                                                                          NINE MONTHS ENDED SEPTEMBER 30,
                                                                          ------------------------------
                                                                              1998         1997
                                                                            ---------    --------

NET INCOME ............................................................     $129,249     $212,144
                                                                            ---------    --------

OTHER COMPREHENSIVE INCOME (LOSS), NET OF TAX:
   Foreign currency translation adjustments ...........................          200         (796)
                                                                            ---------    --------
   Unrealized (losses) gains on securities:
     Unrealized holding (losses) gains arising during period ..........          (20)          50
     Less: reclassification adjustment for gains realized in net income            4          --
                                                                            ---------    --------
     Net unrealized (losses) gains ....................................          (16)          50
                                                                            ---------    --------
   Other comprehensive income (loss) ..................................          184         (746)
                                                                            ---------    --------

COMPREHENSIVE INCOME ..................................................     $129,433     $211,398
                                                                            =========    ========
</TABLE>


   See accompanying notes to the condensed consolidated financial statements.



                                        5



<PAGE>   6



                   NOBLE DRILLING CORPORATION AND SUBSIDIARIES
                 CONDENSED CONSOLIDATED STATEMENTS OF CASH FLOWS
                                 (In thousands)
                                   (Unaudited)
<TABLE>
<CAPTION>

                                                                       NINE MONTHS ENDED 
                                                                         SEPTEMBER 30,
                                                                    ------------------------
                                                                      1998            1997
                                                                    ---------      ---------

CASH FLOWS FROM OPERATING ACTIVITIES
<S>                                                                 <C>            <C>      
  Net income ..................................................     $ 129,249      $ 212,144
  Adjustments to reconcile net income to net cash provided by
    operating activities:
       Depreciation and amortization ..........................        53,811         55,556
       Deferred income tax provision ..........................        12,358         52,665
       Gains on sales of property and equipment ...............          --         (197,676)
       Extraordinary charge, net of tax .......................          --            6,685
       Equity in net income of unconsolidated joint ventures ..         1,806           (222)
       Other ..................................................          (958)           412
       Changes in current assets and liabilities:
        Accounts receivable ...................................        (7,879)       (14,356)
        Proceeds from sale of marketable equity securities, net          --            2,353
        Other assets ..........................................        (6,952)        (1,616)
        Accounts payable ......................................        14,773         34,772
        Other liabilities .....................................        39,483        (12,395)
                                                                    ---------      ---------
        Net cash provided by operating activities .............       235,691        138,322
                                                                    ---------      ---------

CASH FLOWS FROM INVESTING ACTIVITIES
  Purchase of property and equipment ..........................      (423,790)      (251,638)
  Proceeds from sale of property and equipment ................         1,943        268,818
  Investment in and notes receivable from joint ventures ......       (29,925)       (23,875)
  Proceeds from sale of marketable debt securities ............        16,455          3,033
                                                                    ---------      ---------
        Net cash used by investing activities .................      (435,317)        (3,662)
                                                                    ---------      ---------

CASH FLOWS FROM FINANCING ACTIVITIES
  Proceeds from issuance of long-term debt ....................       144,399           --
  Net borrowings on revolving credit facility .................        60,000           --
  Payment of long-term debt ...................................        (9,013)      (128,242)
  Issuance of common stock ....................................         1,751          4,503
  Purchase of shares returned to treasury .....................        (4,313)       (42,309)
                                                                    ---------      ---------
        Net cash provided (used) by financing activities ......       192,824       (166,048)
                                                                    ---------      ---------

DECREASE IN CASH AND CASH EQUIVALENTS .........................        (6,802)       (31,388)

CASH AND CASH EQUIVALENTS, BEGINNING OF PERIOD ................        49,917        149,632
                                                                    ---------      ---------

CASH AND CASH EQUIVALENTS, END OF PERIOD ......................     $  43,115      $ 118,244
                                                                    =========      =========
</TABLE>


   See accompanying notes to the condensed consolidated financial statements.

                                       6
<PAGE>   7


                                                                       FORM 10-Q


NOTE 1 - BASIS OF ACCOUNTING

         The accompanying condensed consolidated financial statements of Noble
Drilling Corporation ("Noble Drilling" or, together with its consolidated
subsidiaries, unless the context requires otherwise, the "Company"), have been
prepared in accordance with generally accepted accounting principles for interim
financial information and with the instructions to Form 10-Q and Article 10 of
Regulation S-X. Accordingly, they do not include all disclosures required by
generally accepted accounting principles for complete financial statements. All
significant transactions among Noble Drilling and its consolidated subsidiaries
have been eliminated. The condensed consolidated financial statements have not
been audited. However, in the opinion of management, all adjustments, consisting
only of normal recurring adjustments, necessary for a fair presentation of the
condensed consolidated financial statements have been included. Results of
operations for interim periods are not necessarily indicative of the results of
operations that may be expected for the entire year. These interim condensed
consolidated financial statements should be read in conjunction with the audited
financial statements and notes thereto included in the Company's Annual Report
on Form 10-K for the year ended December 31, 1997.

         Certain reclassifications have been made in prior year condensed
consolidated financial statements to conform to the classifications used in the
1998 condensed consolidated financial statements. These reclassifications have
no impact on net income.

         Noble Drilling (Paul Romano) Inc. was formed on April 3, 1998 for the
purpose of owning the Noble Paul Romano and financing its conversion to an
EVA-4000(TM) semisubmersible. Noble Drilling (Paul Romano) Inc. is an indirect,
wholly owned subsidiary of Noble Drilling and is operated in a fashion that is
intended to ensure that its assets and liabilities are distinct and separate
from those of the Company and its affiliates and that the creditors of Noble
Drilling (Paul Romano) Inc. would be entitled to satisfy their claims from the
assets of Noble Drilling (Paul Romano) Inc. prior to any distribution to the
Company or its affiliates.

NOTE 2 - EARNINGS PER SHARE

          The Company has adopted SFAS No. 128, Earnings Per Share ("SFAS 128"),
which established new guidelines for computing and presenting earnings per
share. All prior period earnings per share data have been restated to
conform to the provisions of SFAS 128. Net income per common share has been
computed on the basis of the weighted average number of common shares and, where
dilutive, common share equivalents outstanding during the indicated periods.


          The following table reconciles the basic and diluted earnings per
share computations for income before extraordinary charge for the three and nine
month periods ended September 30, 1998 and 1997 (In thousands, except per share
amounts):

<TABLE>
<CAPTION>

                                                INCOME BEFORE
                                                EXTRAORDINARY      BASIC     BASIC   DILUTED    DILUTED
                                                    CHARGE         SHARES     EPS     SHARES      EPS
                                              ------------------------------------------------------------
<S>                                          <C>                <C>        <C>      <C>         <C>  
THREE MONTHS ENDED:
     SEPTEMBER 30, 1998                           $ 32,616        131,302    $0.25   131,736     $0.25
     SEPTEMBER 30, 1997                           $ 33,481        131,382    $0.25   133,130     $0.25
NINE MONTHS ENDED:
     SEPTEMBER 30, 1998                           $129,249        131,195    $0.99   132,234     $0.98
     SEPTEMBER 30, 1997                           $218,829        131,997    $1.66   133,629     $1.64
</TABLE>

          Included in diluted shares are common stock equivalents relating to
outstanding stock options of 434,000 and 1,748,000 for the three month periods
ended September 30, 1998 and 1997, respectively, and 1,039,000 and 1,632,000 for
the nine month periods ended September 30, 1998 and 1997, respectively.

NOTE 3 -ACQUISITIONS/DISPOSITIONS

         In July 1998, the Company purchased the Shelf 6, a Friede & Goldman
9500 Enhanced Pacesetter design semisubmersible, for $24,100,000 in cash. The
unit is currently located at the Dalian Shipyard in China. This unit, which was
built in 1986 and is currently rated to operate in 600 feet of water, is the
same design as the Noble Homer Ferrington and Ilion. Plans call for the Shelf 6
to undergo refurbishment and upgrade for work in deeper water depths upon the
Company securing a long-term drilling contract.


                                       7
<PAGE>   8

                                                                       FORM 10-Q

         On May 7, 1997, the Company completed the sale to Pride Petroleum
Services, Inc. of its 12 mat supported jackup rigs for $268,818,000 in cash. The
Company recognized a pre-tax gain of $197,676,000 ($128,489,000 after-tax) in
connection with the sale, which has been included in "Gains on sales of property
and equipment" in the accompanying Condensed Consolidated Statements of
Operations for the nine months ended September 30, 1997.


NOTE 4 - COMPREHENSIVE INCOME

         As of January 1, 1998, the Company adopted SFAS No. 130, Reporting
Comprehensive Income ("SFAS 130"). SFAS 130 established standards for reporting
and displaying comprehensive income and its components. Components of
comprehensive income are net income and all changes in equity during a period
except those resulting from transactions with owners. SFAS 130 requires
enterprises to display comprehensive income and its components in its financial
statements, to classify items of comprehensive income by their nature in the
financial statements and display the accumulated balance of other comprehensive
income in shareholders' equity separately from retained earnings and additional
paid-in capital. Comparative financial statements provided for earlier periods
have been reclassified to reflect the application of SFAS 130.

         The following table sets forth the components of accumulated other
comprehensive income at September 30, 1998 (In thousands):

<TABLE>
<CAPTION>

                                                                      UNREALIZED GAINS           ACCUMULATED
                                                     FOREIGN              (LOSSES)                  OTHER
                                                    CURRENCY                  ON                COMPREHENSIVE
                                                      ITEMS              SECURITIES                INCOME
                                               --------------------  --------------------    --------------------
<S>                                            <C>                   <C>                     <C>          
      Balance at December 31, 1997..........   $      (1,127)        $         16            $     (1,111)
      Current-period change.................             200                  (16)                    184
                                               ====================  ====================    ====================
      Balance at September 30, 1998.........   $        (927)        $          -            $       (927)
                                               ====================  ====================    ====================
</TABLE>



NOTE 5 - INVESTMENTS IN AND ADVANCES TO JOINT VENTURES

         In June 1998, the Company formed Ilion LLC, a limited liability
company, that purchased the Ilion, a Friede & Goldman 9500 Enhanced Pacesetter
design semisubmersible. The Company has an initial 50 percent equity interest in
Ilion LLC. The total investment balance at September 30, 1998 was $12,619,000.
In addition, the Company has funded $17,100,000 to Ilion LLC in the form of a
convertible promissory note pursuant to which the Company can ultimately
increase its equity interest in Ilion LLC to 70 percent.

         The Ilion is the same design as the Noble Homer Ferrington and is
currently located in Pascagoula, Mississippi. The Noble Homer Ferrington is
currently in the shipyard undergoing refurbishment and upgrade for work in
deeper water depths. Plans call for the Ilion to be similarly upgraded for
deepwater work when the Company receives a long-term contract with an operator.

         Total equity in earnings (loss) was $(1,092,000) and $222,000 for the
three months ended September 30, 1998 and 1997, respectively. Total equity in
earnings (loss) was $(1,806,000) and $222,000 for the nine months ended
September 30, 1998 and 1997, respectively. The loss in 1998 is attributable to
the joint venture that owns and operates the Noble Muravlenko, which is
undergoing the final stages of its water depth and equipment upgrades. The
drillship is scheduled to be available in the fourth quarter of 1998. The
drillship has performed workover operations during a portion of 1998 and, upon
completion of the upgrades, it will begin full drilling operations under a six
year contract with Petrobras.

NOTE 6 - CREDIT FACILITIES

          The Company has an unsecured revolving credit facility in the amount
of $200,000,000 (the "Credit Agreement") through August 14, 2002. As of
September 30, 1998, the Company had an outstanding balance of $60,000,000 under
the Credit Agreement and $4,102,000 had been used to support outstanding letters
of credit. At 

                                       8
<PAGE>   9

                                                                       FORM 10-Q


September 30, 1998, the Company had an additional line of credit totaling
$7,500,000 of which $2,397,000 had been used to support outstanding letters of
credit. Additionally, at September 30, 1998, $24,370,000 of outstanding letters
of credit had been supported through a combination of unsecured letter of credit
facilities and surety bonds. The average interest rate on borrowings under the
Credit Agreement was 6.13 percent for the three months ended September 30, 1998.


NOTE 7 - LONG-TERM DEBT

         In July 1998, Noble Drilling (Paul Wolff) Ltd., an indirect, wholly
owned subsidiary of the Company and owner of the Noble Paul Wolff, issued
$145,000,000 principal amount of its fixed rate senior secured notes (the "Wolff
Notes") in three series. The Wolff Notes bear interest at rates of 6.43 percent
to 6.55 percent per annum. One series of the Wolff Notes matures on December 1,
2001 ($40,000,000 principal amount) and the other two series mature on December
1, 2004. Principal and interest payments are payable quarterly on the first day
of September, December, March and June except that the first two quarterly
payments (and the quarterly payments thereafter through September 1, 2001 in the
case of one series) are interest only. The Wolff Notes are guaranteed by Noble
Drilling and are secured by a first mortgage on the Noble Paul Wolff and, until
completion of its conversion to an EVA-4000(TM) semisubmersible, a first
mortgage on the Noble Roger Eason and Noble Leo Segerius. The Wolff Notes can be
prepaid, in whole or in part, at a premium at any time after June 1, 2001.

         In September 1998, Noble Drilling (Paul Romano) Inc., an indirect,
wholly owned subsidiary of the Company and owner of the Noble Paul Romano,
agreed to issue $112,250,000 principal amount of its fixed rate senior secured
notes (the "Romano Notes") in two series (the "Series A Notes" and the "Series B
Notes"). The Series A Notes will bear interest at 6.24 percent per annum and the
Series B Notes will bear interest at 164 basis points above the five year U.S.
Treasury yield, which will be determined one day prior to funding. These
interest rates are increased by 3 basis points per month for each month after
September 16, 1998 that the Noble Paul Romano has not been accepted by the
contracted operator, Shell Deepwater Development Inc. ("Shell Deepwater"), an
affiliate of Shell Oil Company. The Series A Notes are amortized over 60 months
beginning from the date the rig is accepted by Shell Deepwater. The Series B
Notes are interest only for the first 59 months with a balloon principal payment
in month 60. The Romano Notes are secured by a first naval mortgage on the Noble
Paul Romano. The Romano Notes can be prepaid, in whole or in part, at a premium
at any time. The Series A Notes and Series B Notes will be issued and funding
will occur upon acceptance of the rig by Shell Deepwater, which is expected to
occur in the fourth quarter of 1998. Pursuant to the trust indenture and
security agreement under which the Romano Notes will be issued, the Noble Paul
Romano is restricted from securing any debt of the Company except for the Romano
Notes.


NOTE 8 - FINANCIAL INSTRUMENTS

         The Company operates internationally, resulting in exposure to foreign
currency risk. The Company predominantly denominates its contracts in U.S.
Dollars to mitigate the exposure to fluctuations in foreign currencies. The
Company periodically uses foreign exchange derivative instruments or spot
purchases to hedge its known liabilities in foreign currencies to reduce the
impact of foreign currency gains and losses in its financial results. It is the
Company's policy not to enter into derivative transactions for speculative
purposes. Gains and losses on foreign exchange derivative instruments, which
qualify as accounting hedges, are deferred and recognized when the underlying
foreign exchange exposure is realized. Gains and losses on foreign exchange
derivative instruments that do not qualify as hedges for accounting purposes are
recognized currently based on the change in the market value of the derivative
instrument. During the nine-month period ended September 30, 1998, the Company
entered into various foreign currency exchange contracts. These contracts expire
monthly throughout the remainder of 1998 and require the Company to exchange
U.S. Dollars for Dutch Guilders and British Pounds Sterling totaling $5,600,000
and $3,600,000, respectively. There were no material gains or losses recognized
during the three-month and nine-month periods ended September 30, 1998. At
September 30, 1998 there were no material unrealized gains or losses on open
foreign exchange derivative hedges. The Company did not utilize foreign exchange
derivative instruments in 1997.

         In connection with the project financing for the Noble Paul Romano, on
July 29, 1998, the Company entered into an interest rate swap contract with a
notional amount of $16,875,500 to minimize the Company's exposure to interest
rate increases during the period from July 29, 1998 to the funding date of the
Series B Notes. The funding date is expected to be in the fourth quarter of
1998, and the differential calculated
 

                                       9
<PAGE>   10

                                                                       FORM 10-Q

under the contract will be paid at funding and recognized over the term of the
financing as an adjustment to the effective yield of the underlying financial
instrument.

         In connection with project financing the Company is seeking to obtain
for the Noble Jim Thompson conversion, on June 24, 1998 the Company entered into
an interest rate swap contract with a notional amount of $137,750,000 to
minimize the Company's exposure to interest rate increases during the period
from June 24, 1998 to the termination date of the interest rate swap contract.
On October 30, 1998, the interest rate swap was terminated by the Company,
resulting in a liability of approximately $3,800,000 to the counterparty. This
amount will be paid by the Company on or before December 31, 1998 and will be
recognized over the term of the financing as an adjustment to the effective
yield of the underlying financial instrument.

         In June 1998, the FASB issued SFAS No. 133, Accounting for Derivative
Instruments and Hedging Activities ("SFAS 133"). SFAS 133 requires that, upon
adoption, all derivative instruments (including certain derivative instruments
embedded in other contracts) be recognized in the balance sheet at fair value,
and that changes in such fair values be recognized in earnings unless specific
hedging criteria are met. Changes in the values of derivatives that meet these
hedging criteria will ultimately offset related earnings effects of the hedged
items; effects of certain changes in fair value are recorded in Other
Comprehensive Income pending recognition in earnings. SFAS 133 is effective for
fiscal years beginning after June 15, 1999 and is not expected to have a
material effect on the Company's results of operations or financial position.

NOTE 9 - COMMITMENTS AND CONTINGENCIES

         The Company has entered into agreements with several vendors to
purchase or construct equipment for the conversion of rigs. These agreements
generally require non-refundable payments as certain milestones are met. The
cumulative amount of such payments totaled $198,272,000 through September 30,
1998. As of September 30, 1998, the Company also had $64,606,000 of purchase
commitments with a remaining term in excess of one year related to rig
conversion projects. In the event the Company were to cancel the purchase
commitments, the ultimate amounts refunded would be subject to negotiation.


ITEM 2. MANAGEMENT'S DISCUSSION AND ANALYSIS OF FINANCIAL CONDITION AND RESULTS
        OF OPERATIONS

FORWARD-LOOKING STATEMENTS

         This report on Form 10-Q includes "forward-looking statements" within
the meaning of Section 27A of the Securities Act of 1933, as amended, and
Section 21E of the Securities Exchange Act of 1934, as amended. All statements
other than statements of historical facts included in this Form 10-Q, including,
without limitation, statements contained in this "Management's Discussion and
Analysis of Financial Condition and Results of Operations" regarding the
Company's financial position, business strategy, plans and objectives of
management of the Company for future operations, industry conditions, and
indebtedness covenant compliance, are forward-looking statements. Although the
Company believes that the expectations reflected in such forward-looking
statements are reasonable, it can give no assurance that such expectations will
prove to have been correct. Important factors that could cause actual results to
differ materially from the Company's expectations include, but are not limited
to, intense competition in the drilling industry, volatility of oil and gas
prices, political and economic conditions in international markets in which the
Company conducts operations, decrease in demand for drilling services in the
U.S. Gulf of Mexico ("U.S. Gulf") where the Company has a concentration of
drilling rigs, risks associated with turnkey drilling contracts, early
termination provisions generally found in the Company's offshore drilling
contracts, operational risks (such as blowouts, fires and loss of production),
insurance coverage limitations, and requirements and potential liability imposed
by governmental regulation of the drilling industry (including environmental
regulation).

OUTLOOK

         As used herein, unless otherwise required by the context, "Noble
Drilling" refers to Noble Drilling Corporation and the "Company" refers to Noble
Drilling and its consolidated subsidiaries. The Company's business 

                                       10
<PAGE>   11

                                                                       FORM 10-Q


strategy has been to expand its international and offshore drilling capabilities
through acquisitions and rig upgrades and modifications, and by redeploying
assets in important geological areas. In recent years, the Company has focused
on increasing the number of rigs in its fleet capable of drilling in deeper
water depths. To date, increased levels of activity in offshore world oil and
U.S. natural gas exploration, development and production in deeper water depths
have supported the expansion of the Company's deepwater drilling fleet. Such
activity levels are affected both by short-term and long-term trends in oil and
natural gas prices. During the first nine months of 1998, crude oil prices have
declined significantly as a result of a number of economic and political
factors. As a result, exploration and production expenditures of operators have
been reduced in certain markets in which the Company operates drilling units,
and the utilization and resulting dayrates for the Company's drilling units have
been negatively impacted. Dayrates in the U.S. Gulf, where the Company operates
nine drilling units, have deteriorated significantly over the past nine months
and the Company is also experiencing softness in demand for its rigs currently
located in Venezuela, Mexico and the Middle East. The Company currently has
three rigs stacked in the U.S. Gulf and two rigs are stacked in Venezuela. The
Noble Earl Frederickson is being moved from Venezuela to the U.S. Gulf, where it
will begin operating under a short-term contract for Shell Oil Company in
December 1998. The Company recently received notice of contract termination on
the Noble John Sandifer, which is currently operating in the Bay of Campeche,
Mexico, effective mid November 1998. The Company is currently reviewing
alternative uses for the unit. In the event a contract is not secured in Mexico,
the Noble John Sandifer will most likely be moved to the U.S. Gulf.

         As part of its deepwater expansion strategy, the Company expects to
deliver its first EVA-4000(TM) semisubmersible conversion, the Noble Paul
Romano, in the fourth quarter of 1998 and its second EVA-4000(TM) conversion,
the Noble Paul Wolff, in the first quarter of 1999. Four other semisubmersible
conversions are in progress and are expected to be available for service in 1999
or early 2000. The Noble Paul Romano, which will be capable of drilling in 6,000
feet of water, has been contracted to Shell Deepwater Development Inc. ("Shell
Deepwater"), an affiliate of Shell Oil Company, for a five year contract in the
U.S. Gulf. The Noble Paul Wolff, which will be capable of drilling in 8,900 feet
of water, has been contracted to Petroleo Brasiliero S.A. ("Petrobras") for six
years in Brazil. The Noble Jim Thompson, which will be capable of drilling in
6,000 feet of water, has been contracted to Shell Deepwater for an initial term
of three years, with options to extend by Shell Deepwater, in the U.S. Gulf.
Delivery is anticipated in the first quarter of 1999. The Noble Amos Runner,
which will be capable of drilling in 6,600 foot water depths, has been
contracted to a rig-sharing consortium of operators for a five year term in the
U.S. Gulf. The rig is expected to be delivered in the second quarter of 1999.
The Noble Max Smith will be capable of drilling in 6,000 feet of water. The
Company is currently negotiating to finalize the terms of a drilling contract
with two operators, Amerada Hess Corporation and Union Pacific Resources
Corporation, to work the unit in the U.S. Gulf. The Company expects the term of
the contract to be for five years, with options to the operators to extend. The
rig is expected to be delivered in the third quarter of 1999.

         In addition to the EVA-4000(TM) semisubmersible conversions, the
Company owns or controls three Friede & Goldman 9500 Enhanced Pacesetter
semisubmersibles which it intends to convert to deepwater drilling units. The
Noble Homer Ferrington, which will be capable of drilling in 6,000 feet of
water, is under a letter of intent to a rig-sharing consortium of operators for
a five year term in the U.S. Gulf. Delivery is anticipated in the first quarter
of 2000. In June 1998, the Company formed Ilion LLC, a limited liability
company, that purchased the Ilion, a Friede & Goldman 9500 Enhanced Pacesetter
semisubmersible. The Company has an initial 50 percent equity interest in Ilion
LLC. The Company plans to upgrade the Ilion for deepwater work when a long-term
contract is received. On July 28, 1998, the Company acquired an additional
Friede & Goldman 9500 Enhanced Pacesetter semisubmersible, the Shelf 6. The unit
is currently located at the Dalian Shipyard in China, and the Company intends to
upgrade the rig to work in deeper water depths upon securing a long-term
contract.

         The Noble Roger Eason and the Noble Muravlenko are undergoing the final
stages of their water depth and equipment upgrades and are scheduled to be
available in the fourth quarter of 1998. The drillships have been performing
workover operations during a portion of 1998 and, upon completion of the
upgrades, the drillships will begin full drilling operations under five year and
six year contracts with Petrobras, respectively.

          As a result of the weak demand for offshore drilling services in the
U.S. Gulf, the Company anticipates a decrease in the total number of turnkey
well completions in 1998 as compared to 1997. For the nine months ended
September 30, 1998, there were 6 turnkey well completions. For the year ended
December 31, 1997, there were 35 

                                       11
<PAGE>   12

                                                                       FORM 10-Q

turnkey well completions. Profitability under a turnkey contract is dependent
upon keeping expenses within the estimates used by the Company in determining
the contract price.

RESULTS OF OPERATIONS

FOR THE THREE MONTHS ENDED SEPTEMBER 30, 1998 AND 1997

     GENERAL

         Net income for the third quarter of 1998 (the "Current Quarter") was
$32,616,000, or $0.25 per diluted share, on operating revenues of $195,049,000,
compared to net income of $33,481,000 or $0.25 per diluted share, on operating
revenues of $171,636,000 for the third quarter of 1997 (the "Comparable
Quarter").

     RIG UTILIZATION, OPERATING DAYS AND AVERAGE DAYRATES

         The following table sets forth the average rig utilization rates,
operating days and average dayrates for the Company's rig fleet for the three
months ended September 30, 1998 and 1997:

<TABLE>
<CAPTION>

                                      AVERAGE RIG
                                 UTILIZATION RATES (1)            OPERATING DAYS               AVERAGE DAYRATES
                               --------------------------   ---------------------------   ---------------------------
                                  THREE MONTHS ENDED            THREE MONTHS ENDED            THREE MONTHS ENDED
                                     SEPTEMBER 30,                SEPTEMBER 30,                 SEPTEMBER 30,
                               --------------------------   ---------------------------   ---------------------------
                                      1998      1997                1998      1997                1998      1997
                               ------------  ------------   ------------- -------------   ------------- -------------


<S>                                <C>           <C>            <C>           <C>         <C>           <C>       
    International...........       89%           94%            2,283         2,366       $53,243       $   36,815
    Domestic................       64%           95%              571           614       $41,357       $   39,845
</TABLE>

- - ------------------

(1)  Information reflects the policy of the Company to report utilization rates
     based on the number of actively marketed rigs owned in the fleet.

     INTERNATIONAL OPERATIONS

         The following table sets forth the operating revenues and gross margin
for the Company's international operations for the three months ended September
30, 1998 and 1997:

<TABLE>
<CAPTION>

                                                        REVENUES                         GROSS MARGIN
                                            ---------------------------------  ----------------------------------
                                                   THREE MONTHS ENDED                 THREE MONTHS ENDED   
                                                     SEPTEMBER 30,                       SEPTEMBER 30,     
                                            ---------------------------------  ----------------------------------
                                                 1998             1997              1998              1997
                                            ---------------- ----------------  ----------------  ----------------
                                                                         (In thousands)

<S>                                         <C>              <C>               <C>               <C>         
Contract drilling services..............    $    121,554     $     87,104      $     69,840      $     52,805
Labor contract drilling services........          15,238           14,910             3,471             4,952
Turnkey drilling services...............          23,449            6,752             1,220            (3,101)
Engineering and consulting services.....             260              540              (340)               34
Other revenue...........................           1,465            2,512               507             1,980
                                            ================ ================  ================  ================
         Total..........................    $    161,966     $    111,818      $     74,698      $     56,670
                                            ================ ================  ================  ================
</TABLE>

         OPERATING REVENUES. International contract drilling services revenues
increased $34,450,000 in the Current Quarter as compared to the Comparable
Quarter due primarily to higher average dayrates. Contract drilling revenues in
Qatar, the North Sea and West Africa increased due to certain contract renewals
at higher dayrates. In addition, international contract drilling revenues were
higher due to the Noble John Sandifer being moved to the 

                                       12
<PAGE>   13

                                                                       FORM 10-Q

Bay of Campeche from the U.S. Gulf. International turnkey drilling services
revenues increased $16,697,000 in the Current Quarter as compared to the
Comparable Quarter. There was one turnkey well completion in Mexico in the
Current Quarter as compared to one turnkey well completion in the North Sea in
the Comparable Quarter.

         GROSS MARGIN. International contract drilling services gross margin
increased $17,035,000 in the Current Quarter as compared to the Comparable
Quarter. This was primarily due to higher dayrates received on certain contract
renewals in Qatar, the North Sea and West Africa. The negative results from
international turnkey services in the Comparable Quarter were attributable to
unexpected drilling delays experienced on an offshore turnkey well completed
offshore Mexico.

     DOMESTIC OPERATIONS

         The following table sets forth the operating revenues and gross margin
for the Company's domestic operations for the three months ended September 30,
1998 and 1997:

<TABLE>
<CAPTION>

                                                        REVENUES                           GROSS MARGIN
                                            ----------------------------------   ----------------------------------
                                                   THREE MONTHS ENDED                   THREE MONTHS ENDED
                                                      SEPTEMBER 30,                        SEPTEMBER 30,
                                            ----------------------------------   ----------------------------------
                                                 1998              1997               1998              1997
                                            ---------------   ----------------   ---------------   ----------------
                                                                         (In thousands)

<S>                                         <C>               <C>                <C>               <C>        
Contract drilling services..............    $    23,615       $    24,465        $    14,795       $    19,764
Turnkey drilling services...............          9,420            34,334             (5,456)            3,016
Engineering and consulting services.....              -                 -                  -               365
Other revenue...........................             48             1,019                (23)              542
                                            ===============   ================   ===============   ================
         Total..........................    $    33,083       $    59,818        $     9,316       $    23,687
                                            ===============   ================   ===============   ================
</TABLE>

         OPERATING REVENUES. Domestic contract drilling services revenues
decreased $850,000 in the Current Quarter as compared to the Comparable Quarter
due primarily to lower utilization. Domestic turnkey drilling services revenues
were $24,914,000 lower in the Current Quarter as compared to the Comparable
Quarter due to fewer well completions in the Current Quarter. There was one
domestic turnkey well completion in the Current Quarter as compared to five
turnkey well completions in the Comparable Quarter.

         GROSS MARGIN. Domestic contract drilling services gross margin
decreased $4,969,000 in the Current Quarter as compared to the Comparable
Quarter due primarily to lower utilization rates. Domestic turnkey drilling
services gross margin decreased $8,472,000 in the Current Quarter as compared to
the Comparable Quarter. Turnkey drilling services were negatively affected by
the weak demand for offshore drilling services in the U.S. Gulf. As a result of
the reduced turnkey drilling activity, the Company incurred costs associated
with term contracts on third party rigs which were either not utilized during
the period or were under contract at above current market rates.

     OTHER OPERATING ITEMS

         DEPRECIATION AND AMORTIZATION EXPENSE. Depreciation and amortization
expense decreased $734,000 in the Current Quarter as compared to the Comparable
Quarter due primarily to certain rigs being taken out of active service for
conversion to EVA-4000 TM semisubmersibles.

         INTEREST EXPENSE. Interest expense decreased $435,000 in the Current
Quarter as compared to the Comparable Quarter. The Company capitalized
$4,892,000 of interest costs related to construction in progress on qualifying
upgrade projects during the Current Quarter as compared to $2,073,000 in the
Comparable Quarter.

         INTEREST INCOME. Interest income decreased $779,000 in the Current
Quarter as compared to the Comparable Quarter due to lower average cash balances
in the Current Quarter.

                                       13
<PAGE>   14

                                                                       FORM 10-Q

         INCOME TAX PROVISION. Income tax expense increased $3,337,000 in the
Current Quarter as compared to the Comparable Quarter due primarily to higher
pre-tax earnings on assets owned by domestic entities and taxed at higher U.S.
statutory tax rates.

FOR THE NINE MONTHS ENDED SEPTEMBER 30, 1998 AND 1997

     GENERAL

         Net income for the nine months ended September 30, 1998 (the "Current
Period") was $129,249,000, or $0.98 per diluted share, on operating revenues of
$600,313,000, compared to net income of $212,144,000, or $1.59 per diluted
share, on operating revenues of $525,343,000 for the nine months ended September
30, 1997 (the "Comparable Period").

          Results for the Comparable Period included a pre-tax gain of
$197,676,000 ($128,489,000 after-tax) related to the sale of the mat rigs, and
an extraordinary charge of $6,685,000 resulting from the Company's repurchase of
$110,885,000 principal amount of its 9 1/4 % Senior Notes due 2003 ("9 1/4%
Senior Notes"). Excluding the effects of non-recurring items, net income was
$90,340,000, or $0.68 per diluted share, for the Comparable Period.

         The increases in revenues and net income were principally the result of
higher domestic and international average dayrates and contributions from the
Noble Bill Jennings, Noble Leonard Jones, Noble Lewis Dugger, Noble Joe Alford,
Noble Lester Pettus and Noble Fri Rodli, which were reactivated subsequent to
the end of the Comparable Period. The improved revenue from dayrate increases
and reactivated rigs was partially offset by the sale of the mat rigs in the
second quarter of 1997.

     RIG UTILIZATION, OPERATING DAYS AND AVERAGE DAYRATES

         The following table sets forth the average rig utilization rates,
operating days and average dayrates for the Company's rig fleet for the nine
months ended September 30, 1998 and 1997:

<TABLE>
<CAPTION>

                                      AVERAGE RIG
                                 UTILIZATION RATES (1)            OPERATING DAYS               AVERAGE DAYRATES
                               --------------------------   ---------------------------   ---------------------------
                                   NINE MONTHS ENDED            NINE MONTHS ENDED             NINE MONTHS ENDED
                                     SEPTEMBER 30,                SEPTEMBER 30,                 SEPTEMBER 30,
                               --------------------------   ---------------------------   ---------------------------
                                      1998      1997                1998      1997                1998      1997
                               ------------  ------------   ------------- -------------   ------------- -------------


<S>                                <C>           <C>            <C>           <C>         <C>           <C>       
    International...........       89%           94%            6,825         7,183       $   50,660    $   35,198
    Domestic................       84%           99%            2,176         2,617       $   48,247    $   33,221
</TABLE>

- - ------------------

(1)  Information reflects the policy of the Company to report utilization rates
     based on the number of actively marketed rigs owned in the fleet.

                                       14
<PAGE>   15

                                                                       FORM 10-Q

     INTERNATIONAL OPERATIONS

         The following table sets forth the operating revenues and gross margin
for the Company's international operations for the nine months ended September
30, 1998 and 1997:



<TABLE>
<CAPTION>

                                                        REVENUES                         GROSS MARGIN
                                            ---------------------------------  ----------------------------------
                                                   NINE MONTHS ENDED                   NINE MONTHS ENDED
                                                     SEPTEMBER 30,                       SEPTEMBER 30,  
                                            ---------------------------------  ----------------------------------
                                                 1998             1997              1998              1997
                                            ---------------- ----------------  ----------------  ----------------
                                                                         (In thousands)

<S>                                         <C>              <C>               <C>               <C>         
Contract drilling services..............    $    345,755     $    252,828      $    200,721      $    146,416
Labor contract drilling services........          49,772           34,133            13,586            10,606
Turnkey drilling services...............          26,912           36,302            (2,625)            1,459
Engineering and consulting services.....           1,466            1,894              (203)              521
Other revenue...........................           4,879            6,687             2,397             5,166
                                            ================ ================  ================  ================
         Total..........................    $    428,784     $    331,844      $    213,876      $    164,168
                                            ================ ================  ================  ================
</TABLE>

         OPERATING REVENUES. International contract drilling services revenues
increased $92,927,000 in the Current Period as compared to the Comparable Period
due primarily to higher average dayrates and the mobilization of the Noble John
Sandifer from the U.S. Gulf to the Bay of Campeche. Labor contract drilling
services revenues increased $15,639,000 in the Current Period due primarily to
revenues generated from the Hibernia Project in Canada as well as from higher
average dayrates on the North Sea platform contracts. International turnkey
drilling services revenues decreased $9,390,000 in the Current Period due to
fewer well completions.

         GROSS MARGIN. International contract drilling services gross margin
increased $54,305,000 in the Current Period as compared to the Comparable
Period. This was primarily due to higher dayrates received on certain contract
renewals in all of the Company's international areas of operation. Labor
contract drilling services gross margin increased $2,980,000 in the Current
Period as compared to the Comparable Period due to the contribution of the
Hibernia Project in Canada and higher average dayrates experienced on the North
Sea platform contracts. The negative results from international turnkey drilling
services in the Current Period are attributable to unexpected drilling delays
experienced on an offshore turnkey well completed offshore Mexico.

     DOMESTIC OPERATIONS

         The following table sets forth the operating revenues and gross margin
for the Company's domestic operations for the nine months ended September 30,
1998 and 1997:

<TABLE>
<CAPTION>

                                                        REVENUES                           GROSS MARGIN
                                            ----------------------------------   ----------------------------------
                                                    NINE MONTHS ENDED                    NINE MONTHS ENDED
                                                      SEPTEMBER 30,                        SEPTEMBER 30,
                                            ----------------------------------   ----------------------------------
                                                 1998              1997               1998              1997
                                            ---------------   ----------------   ---------------   ----------------
                                                                         (In thousands)

<S>                                         <C>               <C>                <C>               <C>        
Contract drilling services..............    $   104,985       $    86,940        $    74,905       $    60,665
Turnkey drilling services...............         65,805           103,785              3,748             3,541
Other revenue...........................            739             2,774                186             1,111
                                            ===============   ================   ===============   ================
         Total..........................    $   171,529       $   193,499        $    78,839       $    65,317
                                            ===============   ================   ===============   ================
</TABLE>

                                       15
<PAGE>   16

                                                                       FORM 10-Q

         OPERATING REVENUES. Domestic contract drilling services revenues
increased $18,045,000 in the Current Period as compared to the Comparable Period
due primarily to higher average dayrates and the revenues generated from the
recently reactivated rigs, the Noble Bill Jennings, Noble Leonard Jones, Noble
Joe Alford, Noble Lester Pettus and Noble Fri Rodli. These increases were
partially offset by the move of the Noble John Sandifer to Mexico. Additionally,
domestic contract drilling services revenues were negatively impacted as a
result of the Noble Paul Wolff, Noble Jim Thompson and Noble Amos Runner being
taken out of service in 1997 for conversion to EVA-4000(TM) semisubmersibles.
Domestic turnkey drilling services revenues were $37,980,000 lower in the
Current Period as compared to the Comparable Period due to fewer turnkey well
completions in the Current Period.

         GROSS MARGIN. Domestic contract drilling services gross margin
increased $14,240,000 in the Current Period as compared to the Comparable Period
due primarily to higher average domestic dayrates. The Company experienced
reduced turnkey drilling services profitability in the Current Period resulting
from costs associated with term contracts on third party rigs contracted to the
Company's turnkey operations which were either not utilized during the period or
were under contract at above current market rates. Domestic turnkey drilling
services gross margin for the Comparable Period included losses experienced on
two turnkey wells.

     OTHER OPERATING ITEMS

         DEPRECIATION AND AMORTIZATION EXPENSE. Depreciation and amortization
expense decreased $1,745,000 in the Current Period as compared to the Comparable
Period due primarily to certain submersible rigs being taken out of service for
conversion to EVA-4000 TM semisubmersibles.

         SELLING, GENERAL AND ADMINISTRATIVE EXPENSES. Selling, general and
administrative expenses increased $4,369,000 in the Current Period as compared
to the Comparable Period due primarily to higher personnel costs incurred to
support overall growth of the Company and increased recruiting and training
activity.

         INTEREST EXPENSE. Interest expense decreased $8,288,000 in the Current
Period as compared to the Comparable Period due primarily to the Company's
repurchase of its 9 1/4% Senior Notes in the second quarter of 1997. The Company
capitalized $10,845,000 of interest costs related to construction in progress on
qualifying upgrade projects during the Current Period as compared to $2,073,000
in the Comparable Period.

         INTEREST INCOME. Interest income decreased $2,751,000 in the Current
Period as compared to the Comparable Period due to lower average cash balances
in the Current Period.

         INCOME TAX PROVISION. Income tax expense decreased $43,119,000 in the
Current Period as compared to the Comparable Period. The Comparable Period
included $69,187,000 of taxes related to the gain on the sale of the mat rigs.
Excluding non-recurring items, income tax expense increased $26,068,000 in the
Current Period as compared to the Comparable Period due primarily to higher
pre-tax earnings.


LIQUIDITY AND CAPITAL RESOURCES

      OVERVIEW

         During the Current Quarter, the Company accessed the private debt
markets in connection with project financings for certain of its EVA-4000(TM)
semisubmersible conversions. The Company's borrowings were $60,000,000 under its
$200,000,000 unsecured revolving credit facility (the "Credit Agreement") as of
September 30, 1998. The temporary use of short-term borrowings under the Credit
Agreement resulted in negative working capital of $21,985,000 at September 30,
1998 as compared to positive working capital at December 31, 1997 of
$112,125,000. The Company continues to seek to obtain additional project
financings for certain of its semisubmersible conversion projects. Long-term
debt as a percentage of long-term debt plus shareholders' equity was 17 percent
at September 30, 1998 compared to 11 percent at December 31, 1997.

                                       16
<PAGE>   17

                                                                       FORM 10-Q


         At September 30, 1998, the Company had cash and cash equivalents of
$43,115,000 and had $141,000,000 of funds available under various lines of
credit. The Company expects to generate positive cash flow from operations for
the remainder of 1998, assuming no material decrease in demand for contract
drilling and turnkey services. The Company will continue to have cash
requirements for debt principal and interest payments. For the remainder of
1998, required debt principal and interest payments for currently outstanding
debt are estimated to be approximately $6,867,000. The Company expects to fund
these obligations out of cash and cash equivalents as well as cash expected to
be provided by operations.

         Capital expenditures totaled $423,790,000 and $251,638,000 for the
Current Period and Comparable Period, respectively. Capital expenditures for the
remainder of 1998 are expected to aggregate approximately $121,000,000, of which
the majority are discretionary and relate to upgrades of equipment. This amount
includes approximately $111,000,000 for the conversions of the Noble Paul
Romano, Noble Paul Wolff, Noble Jim Thompson, Noble Amos Runner and Noble Max
Smith to EVA-4000(TM) semisubmersibles. Additionally, the Company expects to
spend approximately $137,000,000 in 1998 and 1999 to upgrade the equipment and
water depth capability on the Noble Homer Ferrington. The conversions of these
rigs will be completed in late 1998 and 1999. The total cost of these six
semisubmersible conversions is expected to be approximately $865,000,000. These
capital expenditures will be funded from operating cash flows, existing cash
balances, available credit facility and lines of credit, and proceeds from both
completed and planned project financings. Proceeds from such project financings
are expected to approximate $370,000,000.

          Given the strong demand for deepwater drilling rigs and related
services, increasingly heavy backlogs for equipment and services required to
complete the conversions could constrain the Company's ability to complete the
conversions on a timely basis. The Company has entered into agreements with
several vendors to purchase or construct equipment for the conversion of units.
These agreements generally require non-refundable payments as certain milestones
are met. The cumulative amount of such payments totaled $198,272,000 through
September 30, 1998. As of September 30, 1998, the Company also had $64,606,000
of purchase commitments with a remaining term in excess of one year related to
rig conversion projects. In the event the Company were to cancel the purchase
commitments, the ultimate amounts refunded would be subject to negotiation.
Certain projects currently being considered by the Company could require, if
they materialize, capital expenditures or other cash requirements not included
in the above estimate. In addition, the Company will continue to evaluate
acquisitions of drilling units from time to time. Factors that could cause
actual capital expenditures to exceed materially the planned capital
expenditures include delays and cost overruns in shipyards, shortages of
equipment, latent damage or deterioration to hull, equipment and machinery in
excess of engineering estimates and assumptions, and changes in design criteria
or specifications during repair or construction.

          In May 1997, the Company's Board of Directors authorized the
repurchase of up to 10,000,000 shares of the Company's common stock, or
approximately eight percent of its then outstanding common stock. As of
September 30, 1998, the Company had repurchased 2,486,000 shares of common stock
at a total cost of $56,494,000. Additional purchases, if any, would be made from
time to time on the open market or in private transactions at prices determined
by the Company.

CREDIT FACILITIES AND LONG-TERM DEBT


          The term of the Company's Credit Agreement extends through August 14,
2002. As of September 30, 1998, the Company had an outstanding balance of
$60,000,000 under the Credit Agreement and $4,102,000 had been used to support
outstanding letters of credit. At September 30, 1998, the Company had an
additional line of credit totaling $7,500,000, of which $2,397,000 had been used
to support outstanding letters of credit. Additionally, at September 30, 1998,
$24,370,000 of outstanding letters of credit had been supported through a
combination of unsecured letter of credit facilities and surety bonds. The
average interest rate on borrowings under the Credit Agreement was 6.13 percent
for the three months ended September 30, 1998. As of October 31, 1998, the
Company had an outstanding balance of $100,000,000 under the Credit Agreement.

                                       17
<PAGE>   18

                                                                       FORM 10-Q

         In July 1998, Noble Drilling (Paul Wolff) Ltd., an indirect, wholly
owned subsidiary of the Company and owner of the Noble Paul Wolff, issued
$145,000,000 principal amount of its fixed rate senior secured notes (the "Wolff
Notes") in three series. The Wolff Notes bear interest at rates of 6.43 percent
to 6.55 percent per annum. One series of the Wolff Notes matures on December 1,
2001 and the other two series mature on December 1, 2004. Principal and interest
payments are payable quarterly on the first day of September, December, March
and June except that the first two quarterly payments (and the quarterly
payments thereafter through September 1, 2001 in the case of one series) are
interest only. The Wolff Notes are guaranteed by Noble Drilling and are secured
by a first mortgage on the Noble Paul Wolff and, until completion of its
conversion to an EVA-4000(TM) semisubmersible, a first mortgage on the Noble
Roger Eason and Noble Leo Segerius. The Wolff Notes can be prepaid, in whole or
in part, at a premium at any time after June 1, 2001.

         In September 1998, Noble Drilling (Paul Romano) Inc., an indirect,
wholly owned subsidiary of the Company and owner of the Noble Paul Romano,
agreed to issue $112,250,000 principal amount of its fixed rate senior secured
notes (the "Romano Notes") in two series (the "Series A Notes" and the "Series B
Notes"). The Series A Notes will bear interest at 6.24 percent per annum and the
Series B Notes will bear interest at 164 basis points above the five year U.S.
Treasury yield, which will be determined one day prior to funding. These
interest rates are increased by 3 basis points per month for each month after
September 16, 1998 that the Noble Paul Romano has not been accepted by the
contracted operator, Shell Deepwater Development Inc. ("Shell Deepwater"), an
affiliate of Shell Oil Company. The Series A Notes are amortized over 60 months
beginning from the date the rig is accepted by Shell Deepwater. The Series B
Notes are interest only for the first 59 months with a balloon principal payment
in month 60. The Romano Notes are secured by a first naval mortgage on the Noble
Paul Romano. The Romano Notes can be prepaid, in whole or in part, at a premium
at any time. The Series A Notes and Series B Notes will be issued and funding
will occur upon acceptance of the rig by Shell Deepwater, which is expected to
occur in the fourth quarter of 1998. Pursuant to the trust indenture and
security agreement under which the Romano Notes will be issued, the Noble Paul
Romano is restricted from securing any debt of the Company except for the Romano
Notes.
 
        The Company believes that its cash and cash equivalents, cash generated
from operations, borrowings under its lines of credit and access to other
financing sources will be adequate to meet its anticipated short-term and
long-term liquidity requirements, including scheduled debt repayments.

FINANCIAL INSTRUMENTS

         The Company occasionally uses financial instruments to hedge against
its exposure to changes in foreign currencies and interest rates. Management
believes that the Company's hedging activities do not expose the Company to any
material interest rate risk, foreign currency exchange rate risk, commodity
price risk or any other market rate or price risk. Although these hedging
arrangements expose the Company to credit risk, the Company monitors the credit
worthiness of its counterparties, which generally are major institutions, and
believes that losses from nonperformance are unlikely to occur.

         The fair value of the Company's long-term debt at September 30, 1998,
was $289,991,000 based on the quoted market prices for similar issues or on the
current rates offered to the Company for debt of similar remaining maturities.

      FOREIGN CURRENCY RISK

         The Company operates internationally, resulting in exposure to foreign
currency risk. The Company predominantly denominates its contracts in U.S.
Dollars to mitigate the exposure to fluctuations in foreign currencies. The
Company periodically uses foreign exchange derivative instruments or spot
purchases to hedge its known liabilities in foreign currencies to reduce the
impact of foreign currency gains and losses in its financial results. It is the
Company's policy not to enter into derivative transactions for speculative
purposes. Gains and losses on foreign exchange derivative instruments, which
qualify as accounting hedges, are deferred and recognized when the underlying
foreign exchange exposure is realized. Gains and losses on foreign exchange
derivative instruments that do not qualify as hedges for accounting purposes are
recognized currently based on the change in the market value of the derivative
instrument. During the nine-month period ended September 30, 1998, the Company
entered into various foreign currency exchange contracts. These contracts expire
monthly throughout the remainder of 1998 and 

                                       18
<PAGE>   19

require the Company to exchange U.S. Dollars for Dutch Guilders and British
Pounds Sterling totaling $5,600,000 and $3,600,000 respectively. There were no
material gains or losses recognized during the three-month and nine-month
periods ended September 30, 1998. At September 30, 1998 there were no material
unrealized gains or losses on open foreign exchange derivative hedges. The
Company did not utilize foreign exchange derivative instruments in 1997.

      INTEREST RATE RISK

         In connection with the project financing for the Noble Paul Romano, on
July 29, 1998, the Company entered into an interest rate swap contract with a
notional amount of $16,875,500 to minimize the Company's exposure to interest
rate increases during the period from July 29, 1998 to the funding date of the
Series B Notes. The funding date is expected to be in the fourth quarter of
1998, and the differential calculated under the contract will be paid at funding
and recognized over the term of the financing as an adjustment to the effective
yield of the underlying financial instrument.

         In connection with project financing the Company is seeking to obtain
for the Noble Jim Thompson conversion, on June 24, 1998 Company entered into an
interest rate swap contract with a notional amount of $137,750,000 to minimize
the Company's exposure to interest rate increases during the period from June
24, 1998 to the termination date of the interest rate swap contract. On October
30, 1998, the interest rate swap was terminated by the Company, resulting in a
liability of approximately $3,800,000 to the counterparty. This amount will be
paid by the Company on or before December 31, 1998 and will be recognized over
the term of the financing as an adjustment to the effective yield of the
underlying financial instrument.

YEAR 2000

          The Company is working to resolve the potential impact of the year
2000 on the ability of the Company's computerized information systems to
accurately process information that may be date-sensitive. Any of the Company's
programs that recognize a date using "00" as the year 1900 rather than the year
2000 could result in errors or system failures. The Company is managing its year
2000 compliance issues through a committee ("Y2K Committee"), which was formed
to develop the Company's year 2000 initiatives. As of November 1, 1998, the Y2K
Committee has taken steps to review the Company's critical information
technology ("IT") systems, such as computer hardware and software, and non
information technology ("Non-IT") systems, which include computer controlled
equipment and electronic devices which are used to operate equipment on the
Company's drilling units. Telephone systems and other office-based electronic
equipment systems are also being considered in the assessment of Non-IT systems.
The Y2K Committee has completed the initial phase of the initiative through
communication to all employees and research of year 2000 compliance issues. The
Y2K Committee is currently identifying and reviewing all of the Company's IT and
Non-IT systems to determine which systems are not year 2000 compliant and will
need to be replaced or modified.

          The Y2K Committee has also initiated and/or received communication
from most of the Company's customers, suppliers and service providers on year
2000 issues to determine the extent to which the Company may be exposed to the
disruption of business activities in the event these third parties fail to
correct their year 2000 system deficiencies. Although there is currently no
indication that the various companies on which the Company relies on will not
resolve their year 2000 compliance issues, there can be no guarantee that the
systems of such companies on which the Company relies on will be corrected on a
timely basis. Additionally, there can be no guarantee that the Company will not
encounter an unexpected year 2000 problem.

          The Y2K Committee will be developing and initiating corrective
measures based on completion of the internal and external IT and Non-IT systems
reviews during the fourth quarter of 1998. However, if the Company and third
parties upon which it relies are unable to address this issue in a timely
manner, it could result in a material adverse impact to the results of
operations and financial position of the Company. In the event the Company or
the various companies on which the Company relies on experience year 2000
compliance problems, adverse business consequences could result. Such adverse
consequences could include the interruption of drilling services aboard the
Company's drilling units, delays in shipments of materials and supplies required
to operate the Company's drilling units, delays in transferring personnel to and
from the drilling units and delays in receiving funds from customers or in
making payments to suppliers.

                                       19
<PAGE>   20

                                                                       FORM 10-Q

          The Company has not yet developed a contingency plan for year 2000
issues to address worst-case business interruptions. However, once all of the
identification and reviews of system issues are completed, a contingency plan
will be developed to mitigate the risk of business interruptions.


ITEM 3. QUANTITATIVE AND QUALITATIVE DISCLOSURES ABOUT MARKET RISK

           For information on foreign currency risk and interest rate risk, see
"Item 2. Management's Discussion and Analysis of Financial Condition and Results
of Operations - Financial Instruments."

                           PART II. OTHER INFORMATION

ITEM 5. OTHER INFORMATION

         On November 3, 1998, the Company announced that Robert D. Campbell
would become President of Noble Drilling effective January 1, 1999. James C. Day
will continue as Noble Drilling's Chairman and Chief Executive Officer. Mr.
Campbell holds a bachelor of science degree in chemical engineering and a doctor
of jurisprudence degree from The University of Texas at Austin. He has practiced
corporate/securities law with the law firm of Thompson & Knight, P.C. for the
past 21 years. Mr. Campbell has been associated with the Company since 1977 and
has served as general corporate counsel and general counsel since Noble Drilling
went public in 1985.

ITEM 6. EXHIBITS AND REPORTS ON FORM 8-K

         (a)    Exhibits.

                The information required by this Item 6(a) is set forth in the
                Index to Exhibits accompanying this quarterly report and is
                incorporated herein by reference.

         (b)    No reports on Form 8-K were filed by the Company during the 
                quarter ended September 30, 1998.


                                       20
<PAGE>   21
                                                                       FORM 10-Q


                                   SIGNATURES

         Pursuant to the requirements 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.



                                         NOBLE DRILLING CORPORATION




DATE:    November 16, 1998                      /s/ JAMES C. DAY
                                         -------------------------------------
                                         JAMES C. DAY, Chairman, President and
                                         Chief Executive Officer



DATE:    November 16, 1998                     /s/ BYRON L. WELLIVER
                                         -------------------------------------
                                         BYRON L. WELLIVER,
                                         Senior Vice President-Finance,
                                         Treasurer and Controller
                                         (Principal Financial and Accounting 
                                            Officer)


                                       21
<PAGE>   22

                                                                       FORM 10-Q


                                INDEX TO EXHIBITS

<TABLE>
<CAPTION>
EXHIBIT 
NUMBER                              EXHIBIT 
- - -------                             ------- 
<S>       <C>
4.1       Note Purchase Agreement, dated as of September 24, 1998, by and
          between Noble Drilling (Paul Romano) Inc. and Banner Receivables
          Corporation. Noble Drilling (Paul Romano) Inc. has entered into a
          separate Note Purchase Agreement with each purchaser of its notes,
          which agreements are substantially identical in all material respects,
          except for the principal amount of notes purchased. A schedule
          identifying each of the note purchasers that entered into a Note
          Purchase Agreement with Noble Drilling (Paul Romano) Inc. and the
          principal amount of notes purchased by each such note purchaser is
          included as Schedule A to the Note Purchase Agreement.

4.2       Form of Indenture and Security Agreement to be entered into between
          Noble Drilling (Paul Romano) Inc. and Chase Bank of Texas, National
          Association, as Trustee.

4.3       Form of First Naval Mortgage covering the Noble Paul Romano to be made
          by Noble Drilling (Paul Romano) Inc. in favor of Chase Bank of Texas,
          National Association, as Indenture Trustee.

4.4       Note Purchase Agreement, dated as of July 1, 1998, by and between
          Noble Drilling (Paul Wolff) Ltd., Chase Bank of Texas, National
          Association, as Trustee, and Security Connecticut Life Insurance
          Company. Noble Drilling (Paul Wolff) Ltd. has entered into a separate
          Note Purchase Agreement with each purchaser of its notes, which
          agreements are substantially identical in all material respects,
          except for the principal amount of notes purchased. A schedule
          identifying each of the note purchasers that entered into a Note
          Purchase Agreement with Noble Drilling (Paul Wolff) Ltd. and the
          principal amount of notes purchased by each such note purchaser is
          included as Annex I to the Note Purchase Agreement.

4.5       Indenture of First Naval Mortgage, dated as of July 1, 1998, made by
          Noble Drilling (Paul Wolff) Ltd. in favor of Chase Bank of Texas,
          National Association, as Trustee.

4.6       Parent Guaranty, dated as of July 1, 1998, by Noble Drilling
          Corporation in favor of Chase Bank of Texas, National Association, as
          Trustee.

4.7       Second Amendment, dated September 10, 1998, to Credit Agreement, dated
          as of August 14, 1997, among Noble Drilling Corporation, the lending
          institutions listed from time to time on Annex I to the Credit
          Agreement, Credit Lyonnais, New York Branch, as Documentation Agent,
          and Christiana Bank Og Kreditkasse ASA, New York Branch, as
          Administrative Agent.

10.1*     Employment Agreement, dated as of October 22, 1998, by and between
          Noble Drilling Corporation and James C. Day.

10.2*     Employment Agreement, dated as of October 22, 1998, by and between
          Noble Drilling Corporation and Byron L. Welliver.

10.3*     Employment Agreement, dated as of October 22, 1998, by and between
          Noble Drilling Corporation and Julie J. Robertson.

27        Financial Data Schedule
</TABLE>

- - ----------------
*         Management contract or compensatory plan or arrangement required to be
          filed as an exhibit hereto.

<PAGE>   1
                                                                     EXHIBIT 4.1


                        NOBLE DRILLING (PAUL ROMANO) INC.

                  $95,412,500 Senior Secured Notes -- Series A
                  $16,837,500 Senior Secured Notes -- Series B





                     --------------------------------------





                             NOTE PURCHASE AGREEMENT
                        (Banner Receivables Corporation)




                     ---------------------------------------


                         Dated as of September 24, 1998



<PAGE>   2




                                TABLE OF CONTENTS
<TABLE>
<CAPTION>


<S>     <C>                                                                                                       <C>

1.       AUTHORIZATION OF NOTES...................................................................................1

2.       SALE AND PURCHASE OF NOTES...............................................................................2

3.       CLOSING..................................................................................................2

4.       CONDITIONS TO CLOSING....................................................................................3
         4.1.     REPRESENTATIONS AND WARRANTIES..................................................................3
         4.2.     PERFORMANCE; NO DEFAULT.........................................................................3
         4.3.     TRUST INDENTURE.................................................................................3
         4.4.     DRILLING RIG....................................................................................3
         4.5.     NOBLE US AND NOBLE CORP. .......................................................................4
         4.6.     SHELL CONTRACT AND SDDI.........................................................................5
         4.7.     CERTAIN DOCUMENTS...............................................................................5
         4.8.     COMPLIANCE CERTIFICATES.........................................................................5
         4.9.     OPINIONS OF COUNSEL.............................................................................6
         4.10.    PURCHASE PERMITTED BY APPLICABLE LAW, ETC. .....................................................6
         4.11.    SALE OF OTHER NOTES.............................................................................6
         4.12.    PAYMENT OF SPECIAL COUNSEL FEES.................................................................6
         4.13.    PRIVATE PLACEMENT NUMBER........................................................................7
         4.14.    NOTES...........................................................................................7
         4.15.    DEBT SERVICE RESERVE FUND; WORKING CAPITAL FUND.................................................7
         4.16.    MATERIAL ADVERSE CHANGE.........................................................................7
         4.17.    CHANGES IN CORPORATE STRUCTURE..................................................................7
         4.18.    PROCEEDINGS AND DOCUMENTS.......................................................................7
         4.19.    TRUSTEE.........................................................................................7
         4.20.    AGENT FOR SERVICE OF PROCESS....................................................................8
         4.21.    FILING OF DOCUMENTS.............................................................................8

5.       REPRESENTATIONS AND WARRANTIES OF THE COMPANY............................................................8
         5.1.     ORGANIZATION; POWER AND AUTHORITY...............................................................8
         5.2.     AUTHORIZATION, ETC. ............................................................................8
         5.3.     DISCLOSURE......................................................................................9
         5.4.     ORGANIZATION AND OWNERSHIP OF BORROWER AND NOBLE US.............................................9
         5.5.     FINANCIAL STATEMENTS............................................................................9
         5.6.     COMPLIANCE WITH LAWS, OTHER INSTRUMENTS, ETC. ..................................................9
         5.7.     GOVERNMENTAL AUTHORIZATIONS, ETC. .............................................................10
         5.8.     LITIGATION; OBSERVANCE OF STATUTES AND ORDERS..................................................10
         5.9.     TAXES..........................................................................................10
         5.10.    TITLE TO PROPERTY..............................................................................11
         5.11.    LICENSES, PERMITS, ETC. .......................................................................11
         5.12.    COMPLIANCE WITH ERISA..........................................................................11
         5.13.    PRIVATE OFFERING BY THE COMPANY................................................................12

</TABLE>

                                       -i-


<PAGE>   3

<TABLE>
<CAPTION>


SECTION                                                                                                        PAGE
- - -------                                                                                                        ----
<S>      <C>      <C>                                                                                          <C>

         5.14.    USE OF PROCEEDS; MARGIN REGULATIONS............................................................12
         5.15.    DEBT...........................................................................................13
         5.16.    FOREIGN ASSETS CONTROL REGULATIONS, ETC. ......................................................13
         5.17.    STATUS UNDER CERTAIN STATUTES..................................................................13
         5.18.    SUBSIDIARIES...................................................................................13
         5.19.    NATURE OF BUSINESS AND LOCATION OF BUSINESS AND OFFICES........................................13
         5.20.    ENVIRONMENTAL MATTERS..........................................................................14
         5.21.    SHELL CONTRACT.................................................................................15
         5.22.    NO INDENTURE DEFAULTS..........................................................................15
         5.23.    RIG CLASSIFICATION.............................................................................15
         5.24.    INSURANCE......................................................................................15
         5.25.    SECURITY INTERESTS.............................................................................15
         5.26.    YEAR 2000......................................................................................16
         5.27.    SDDI ACKNOWLEDGMENT AND CONSENT................................................................16

6.       REPRESENTATIONS OF THE PURCHASER........................................................................16
         6.1.     PURCHASE FOR INVESTMENT........................................................................16
         6.2.     SOURCE OF FUNDS. ..............................................................................16

7.       EXPENSES, ETC. .........................................................................................18
         7.1.     TRANSACTION EXPENSES...........................................................................18
         7.2.     SURVIVAL.......................................................................................18

8.       SURVIVAL OF REPRESENTATIONS AND WARRANTIES..............................................................18

9.       AMENDMENT AND WAIVER....................................................................................19
         9.1.     REQUIREMENTS...................................................................................19
         9.2.     SOLICITATION OF HOLDERS OF NOTES...............................................................19
         9.3.     BINDING EFFECT, ETC. ..........................................................................19
         9.4.     NOTES HELD BY COMPANY, ETC. ...................................................................20

10.      NOTICES.................................................................................................20

11.      REPRODUCTION OF DOCUMENTS...............................................................................20

12.      CONFIDENTIAL INFORMATION................................................................................21

13.      SUBSTITUTION OF PURCHASER...............................................................................22

14.      MISCELLANEOUS...........................................................................................22
         14.1.    SUCCESSORS AND ASSIGNS.........................................................................22
         14.2.    PAYMENTS DUE ON NON-BUSINESS DAYS..............................................................22
         14.3.    SEVERABILITY...................................................................................22

</TABLE>

                                      -ii-


<PAGE>   4


<TABLE>
<CAPTION>


SECTION                                                                                                        PAGE
- - -------                                                                                                        ----
<S>      <C>      <C>                                                                                          <C>

         14.4.    CONSTRUCTION...................................................................................22
         14.5.    COUNTERPARTS...................................................................................23
         14.6.    GOVERNING LAW..................................................................................23
         14.7.    FINAL AGREEMENT................................................................................23


</TABLE>




                                      -iii-


<PAGE>   5

<TABLE>


<S>               <C>      <C>
SCHEDULE A        --       INFORMATION RELATING TO PURCHASERS

SCHEDULE B        --       DEFINED TERMS

SCHEDULE 4.17*    --       Changes in Corporate Structure

SCHEDULE 5.3*     --       Disclosure Materials

SCHEDULE 5.7*     --       Governmental Authorizations

SCHEDULE 5.8*     --       Certain Litigation

SCHEDULE 5.11*    --       Patents, Permits, etc.

EXHIBIT 1*        --       Trust Indenture and Security Agreement

EXHIBIT 2*        --       Asset Transfer Agreement

EXHIBIT 3*        --       Capital Funding Agreement

EXHIBIT 4*        --       Operating Services Agreement

EXHIBIT 5*        --       Performance Agreement

EXHIBIT 6*        --       First Naval Mortgage

EXHIBIT 7*        --       Assignment of Drilling Contract Revenue

EXHIBIT 8*        --       Opinion of Thompson & Knight, P.C.

EXHIBIT 9*        --       Opinion of Roy Phillipps, P.

EXHIBIT 10*       --       Opinion of Chapman and Cutler

EXHIBIT 11*       --       Opinion of Chan Warner P.C.

EXHIBIT 12*       --       Opinion of Vinson & Elkins L.L.P.

EXHIBIT 13*       --       SDDI Acceptance Certificate

EXHIBIT 14*       --       SDDI Acknowledgment and Consent

</TABLE>

- - ----------------

* Not filed as part of this Exhibit 4.1 or as a separate exhibit to this
Quarterly Report on Form 10-Q. The Company undertakes to furnish supplementally
a copy of any omitted material to the Commission upon request.


                                      -iv-


<PAGE>   6



                        NOBLE DRILLING (PAUL ROMANO) INC.
                        10370 Richmond Avenue, Suite 580
                              Houston, Texas 77042


                          Series A Senior Secured Notes
                          Series B Senior Secured Notes


                                                              September 24, 1998


TO THE PURCHASER LISTED IN THE ATTACHED
         SCHEDULE A WHICH IS A SIGNATORY HERETO:

Ladies and Gentlemen:

         Noble Drilling (Paul Romano) Inc., a Delaware corporation (the
"COMPANY"), agrees with you as follows:

1.       AUTHORIZATION OF NOTES.

         The Company will authorize the issue and sale of its promissory notes
described as follows:

         (a)      $95,412,500 aggregate principal amount of Series A Senior
                  Secured Notes, payable in installments with final installment
                  due on the Maturity Date (the "SERIES A NOTES", such term to
                  include any such notes issued in substitution therefor
                  pursuant to the Trust Indenture (hereinafter defined)). The
                  Series A Notes shall have the terms (including interest rate)
                  and provisions and be substantially in form attached as Annex
                  A-1 of the Trust Indenture;

         (b)      $16,837,500 aggregate principal amount of Series B Senior
                  Secured Notes, payable on the Maturity Date (the "SERIES B
                  NOTES", such term to include any such notes issued in
                  substitution therefor pursuant to the Trust Indenture). The
                  Series B Notes shall have the terms (including interest rate)
                  and provisions and be substantially in form attached as Annex
                  A-2 to the Trust Indenture;

         (c)      All of the Series A Notes and the Series B Notes (all such
                  Notes are herein collectively called the "NOTES") shall be
                  issued on the Purchase Date under and pursuant to the Trust
                  Indenture and be subject to the terms and provisions thereof.
                  Certain capitalized terms used in this Agreement are defined
                  in Schedule B; references to a "Schedule" or an "Exhibit" are,
                  unless otherwise specified, to a Schedule or an Exhibit
                  attached to this Agreement.





<PAGE>   7



2.       SALE AND PURCHASE OF NOTES.

         Subject to the terms and conditions of this Agreement, the Company will
issue and sell to you and you will purchase from the Company, at the Closing
provided for in Section 3, Notes of the Series and in the principal amount
specified opposite your name in Schedule A at the purchase price of 100% of the
principal amount thereof. Contemporaneously with entering into this Agreement,
the Company is entering into separate Note Purchase Agreements (the "OTHER
AGREEMENTS") identical with this Agreement with each of the other purchasers
named in Schedule A (the "OTHER PURCHASERS"), providing for the sale at such
Closing to each of the Other Purchasers of Notes of the Series and in the
principal amount specified opposite its name in Schedule A. Your obligation
hereunder and the obligations of the Other Purchasers under the Other Agreements
are several and not joint obligations and you shall have no obligation under any
Other Agreement and no liability to any Person for the performance or
non-performance by any Other Purchaser thereunder.

         The interest rate on the Notes will increase by 3 basis points if the
Purchase Date has not occurred and the Closing consummated on or before
September 15, 1998. An additional 3 basis points shall be added to the interest
rate on the 16th day of each calendar month thereafter starting October 16,
1998, if the Purchase Date and the Closing have failed to occur prior thereto,
until March 16, 1999 (the "COMMITMENT TERMINATION DATE"), on which date your
obligation to purchase Notes hereunder shall terminate.

         If the Purchase Date has not occurred and the Closing consummated on or
before the Commitment Termination Date, the Company will pay to you on the
Commitment Termination Date a make-whole fee in the amount of the "MAKE-WHOLE
AMOUNT." The "Make-Whole Amount" shall be determined as provided in Section 3.8
of the Trust Indenture; provided that for purposes hereof such determination
shall be made as if the Notes had been issued to you as provided in this
Agreement on the Commitment Termination Date, the full principal balance thereof
repaid on such date (being the "SETTLEMENT DATE" for such determination) and the
words ".32% (WITH RESPECT TO THE SERIES A NOTES ) AND .32% (WITH RESPECT TO THE
SERIES B NOTES ) OVER THE YIELD TO MATURITY" used in the definition of the
"REINVESTMENT YIELD," for purposes of such determination shall be deemed to read
".50% OVER THE YIELD TO MATURITY," "MATURITY" being the maturity that said Notes
would have had they been issued on said Commitment Termination Date.

3.       CLOSING.

         The sale and purchase of the Notes to be purchased by you and the Other
Purchasers shall occur at the offices of Vinson & Elkins L.L.P., 35th Floor,
First City Tower, 1001 Fannin, Houston, Texas 77002, at 9:00 a.m., Central time,
at a closing (the "CLOSING") on the Purchase Date or on such other Business Day
thereafter on or prior to March 16, 1999, as may be agreed upon by the Company
and you and the Other Purchasers. At the Closing the Company will deliver to you
the Notes to be purchased by you in the form of a single Note (or such greater
number of Notes in denominations of at least $500,000 as you may request) dated
the date of the Closing and registered in your name (or in the name of your
nominee), against delivery by you to the Company or its order of immediately
available funds in the amount of the purchase price therefor by wire transfer of
immediately available funds for the account of the Company as follows:


                                       -2-


<PAGE>   8



                  Noble Drilling (Paul Romano) Inc.
                  Houston, TX
                  Account No. 324159
                  Southwest Bank of Texas, NA
                  Houston, TX
                  ABA 113011258

If at the Closing the Company shall fail to tender such Notes as provided above
in this Section 3, or any of the conditions specified in Section 4 shall not
have been fulfilled to your satisfaction, you shall, at your election, be
relieved of all further obligations under this Agreement, without thereby
waiving any rights you may have by reason of such failure or such
nonfulfillment.

4.       CONDITIONS TO CLOSING.

         Your obligation to purchase and pay for the Notes to be sold to you at
the Closing is subject to the fulfillment to your satisfaction, prior to or at
the Closing, of the following conditions:

4.1.     REPRESENTATIONS AND WARRANTIES.

         The representations and warranties of the Company and Noble US in this
Agreement and the other Credit Documents shall be correct in all material
respects when made and at the time of the Closing.

4.2.     PERFORMANCE; NO DEFAULT.

         The Company and Noble US shall have performed and complied with and
shall continue to be in compliance with all agreements and conditions contained
in this Agreement, the Trust Indenture and the other Credit Documents required
to be performed or complied with by it prior to or at the Closing and after
giving effect to the issue and sale of the Notes (and the application of the
proceeds thereof as contemplated by Section 5.14) no Indenture Default or
Indenture Event of Default shall have occurred and be continuing.

4.3.     TRUST INDENTURE.

         The Company and the Trustee shall have entered into the Trust Indenture
and Security Agreement (the "TRUST INDENTURE"), which shall be to the effect and
substantially in the form of Exhibit 1 hereto, and the Notes shall have been
duly issued and executed by the Company and duly authenticated and delivered by
the Trustee as provided in the Trust Indenture.

4.4.     DRILLING RIG.

                  (a) The Drilling Rig shall have (i) completed its conversion
         into a deep water moored semisubmersible drilling unit in compliance
         with the EVA-4000 (tm) design specifications and the Shell Contract,
         including but not limited to the overhaul and reconditioning of the
         Drilling Rig's machinery and systems including all upgrades and
         modifications to such machinery and systems, (ii) successfully
         completed and passed all

                                       -3-


<PAGE>   9



         required regulatory inspections and certifications, (iii) successfully
         completed all sea trials and (iv) successfully conducted, completed and
         passed acceptance tests on all drilling related machinery, equipment
         and systems, and shall have been accepted by SDDI; in each case as
         evidenced by the SDDI Acceptance Certificate.

                  (b) The Drilling Rig shall have been classified in the highest
         class available for rigs of its age and type by the American Bureau of
         Shipping and you shall have received copies of such classification
         certifications.

                  (c) You shall have received a copy of the Rig Appraisal and
         Engineering Report addressed to you or accompanied by a letter
         permitting you to rely thereon.

                  (d) The Company shall have valid legal and beneficial title to
         the Drilling Rig free and clear of all Liens and other encumbrances,
         except for Excepted Liens in an aggregate amount not in excess of
         $5,000,000.

                  (e) The Drilling Rig shall be duly and validly registered in
         the name of the Company under the laws and flag of the Republic of
         Panama as a documented marine vessel.

                  (f) The Company shall provide (at no expense to you) evidence
         satisfactory to you that it maintains the insurance called for in
         Section 7.3 of the Trust Indenture and Section 2.13 of the First Naval
         Mortgage including, without limitation, a report of an independent
         insurance consultant reasonably acceptable to you.

4.5.     NOBLE US AND NOBLE CORP.

                  (a) Noble US and (except in the case of the Performance
         Agreement) the Company shall have executed and delivered to the
         Trustee, with a copy to you, of the following agreements, each of which
         shall be in full force and effect:

                           (i)      Asset Transfer Agreement;

                           (ii)     Operating Services Agreement; and

                           (iii)    Performance Agreement.

                  (b) Noble Corp. shall have executed and delivered to the
         Trustee and you a letter (i) certifying that the unaudited consolidated
         financial statements of Noble US referred to in Section 5.5 hereof
         fairly present in all material respects the consolidated financial
         position and results of operations of Noble US and its Subsidiaries for
         each of the years and at each of the dates set forth therein, (ii)
         certifying that since December 31, 1997, there has been no change in
         the financial condition, operations, business or properties of Noble US
         and its Subsidiaries except changes that individually or in the
         aggregate would not reasonably be expected to have a Material Adverse
         Effect and (iii) covenanting to maintain direct or indirect ownership
         of all of the outstanding shares of capital stock of each of Noble US
         and the Company so long as any Notes are outstanding.

                                       -4-


<PAGE>   10



4.6.     SHELL CONTRACT AND SDDI.

                  (a) The Shell Contract shall be in full force and effect
         without amendment, modification or waiver except as would be permitted
         by Section 7.3(d) of the Trust Indenture and no defaults or events
         which with the lapse of time or the giving of notice will create a
         default shall have occurred and be continuing thereunder.

                  (b) SDDI shall have accepted the Drilling Rig as being in
         compliance with the Shell Contract for all intents and purposes and
         without waiver of any material conditions thereof as evidenced by the
         execution and delivery of the SDDI Acceptance Certificate.

                  (c) SDDI shall have executed and delivered to the Trustee with
         a copy to you the SDDI Acknowledgment and Consent.

                  (d) SDDI shall be 100% owned directly or indirectly by Royal
         Dutch Shell.

                  (e) The Company shall have received a valid and enforceable
         assignment of the Shell Contract pursuant to the Asset Transfer
         Agreement.

                  (f) You shall have received copies of the Shell Contract, and
         all amendments thereto, and the Panamanian Bill of Sale and Acceptance
         of Sale in respect of the Drilling Rig, certified as true, accurate and
         complete by the Company and Noble US.

4.7.     CERTAIN DOCUMENTS.

         The Company shall have executed and delivered to the Trustee, with a
copy to you, of the following:

                  (i) First Naval Mortgage;

                  (ii) Assignment of Drilling Contract Revenue;

                  (iii) appropriate Financing Statements and other filing and
         recording documents as necessary to properly perfect the liens
         evidenced by the Trust Indenture, the First Naval Mortgage and the
         Assignment of Drilling Contract Revenue; and

                  (iv) all other Credit Documents to which the Company is a
         party.

4.8.     COMPLIANCE CERTIFICATES.

                  (a) The Company shall have delivered to you an Officer's
         Certificate dated the date of the Closing, certifying that the
         conditions specified in Section 4 have been fulfilled.

                  (b) Noble US shall have delivered to you an Officer's
         Certificate dated the date of the Closing, certifying that the
         conditions specified in Section 4 with respect to it have been
         fulfilled.

                                       -5-


<PAGE>   11



                  (c) Each of the Company and Noble US shall have delivered to
         you (i) a certified copy of its certificate of incorporation, (ii) a
         certificate of its secretary or an assistant secretary certifying (A)
         the absence of any amendments to its certificate of incorporation since
         the date of such certified copy, (B) its bylaws, (C) the due adoption
         or approval by its board of directors of resolutions attached to such
         certificate relating to the transactions contemplated hereby and (D)
         the incumbency of each of its officers who has executed any of the
         Credit Documents, and (iii) a good standing certificate from its state
         of incorporation.

4.9.     OPINIONS OF COUNSEL.

         You shall have received opinions dated the date of the Closing (a) from
Thompson & Knight P.C., counsel for the Company and Noble US substantially in
the form of Exhibit 8 hereto, (b) from Roy Phillipps P., your special Panamanian
counsel in connection with Drilling Rig and the First Naval Mortgage,
substantially in the form of Exhibit 9 hereto, (c) from Chapman and Cutler, your
special counsel, substantially in the form of Exhibit 10 hereto, (d) from Chan
Warner P.C., counsel to the Trustee, substantially in the form of Exhibit 11
hereto, and (e) from Vinson & Elkins L.L.P. in the form of Exhibit 12 hereto.

4.10.    PURCHASE PERMITTED BY APPLICABLE LAW, ETC.

         On the date of the Closing your purchase of Notes shall (i) be
permitted by the laws and regulations of each jurisdiction to which you are
subject, without recourse to provisions (such as Section 1405(a)(8) of the New
York Insurance Law) permitting limited investments by insurance companies
without restriction as to the character of the particular investment, (ii) not
violate any applicable law or regulation (including, without limitation,
Regulation T, U or X of the Board of Governors of the Federal Reserve System)
and (iii) not subject you to any tax, penalty or liability under or pursuant to
any applicable law or regulation, which law or regulation was not in effect on
the date hereof. If requested by you, you shall have received an Officer's
Certificate certifying as to such matters of fact as you may reasonably specify
to enable you to determine whether such purchase is so permitted.

4.11.    SALE OF OTHER NOTES.

         Contemporaneously with the Closing the Company shall sell to the Other
Purchasers and the Other Purchasers shall purchase the Notes to be purchased by
them at the Closing as specified in Schedule A.

4.12.    PAYMENT OF SPECIAL COUNSEL FEES.

         Without limiting the provisions of Section 7.1, the Company shall have
paid on or before the Closing the reasonable fees, charges and disbursements of
your special counsel to the extent reflected in a statement of such counsel
rendered to the Company at least one Business Day prior to the Closing.


                                       -6-


<PAGE>   12



4.13.    PRIVATE PLACEMENT NUMBER.

         A Private Placement number issued by Standard & Poor's CUSIP Service
Bureau (in cooperation with the Securities Valuation Office of the National
Association of Insurance Commissioners) shall have been obtained for each series
of the Series A Notes.

4.14.    NOTES - RATING.

         The Series A Notes shall have been rated no lower than AA by Duff &
Phelps Credit Rating Co. and the Series B Notes shall have been rated no lower
than A by Duff & Phelps Credit Rating Co.

4.15.    DEBT SERVICE RESERVE FUND; WORKING CAPITAL FUND.

         Each of the Debt Service Reserve Fund and Working Capital Fund shall
have been established with the Trustee and funded pursuant to the Trust
Indenture.

4.16.    MATERIAL ADVERSE CHANGE.

         No event or condition shall have occurred which reasonably may be
expected to cause a Material Adverse Effect with respect to the Company or Noble
US.

4.17.    CHANGES IN CORPORATE STRUCTURE.

         Except as specified in Schedule 4.17, neither the Company nor Noble US
shall have changed its jurisdiction of incorporation or been a party to any
merger or consolidation nor shall it have succeeded to all or any substantial
part of the liabilities of any other entity, at any time following the date of
the most recent financial statements referred to in Section 5.5.

4.18.    PROCEEDINGS AND DOCUMENTS.

         All corporate and other proceedings in connection with the transactions
contemplated by this Agreement and all documents and instruments incident to
such transactions shall be reasonably satisfactory to you and your special
counsel, and you and your special counsel shall have received all such
counterpart originals or certified or other copies of such documents as you or
they may reasonably request.

4.19.    TRUSTEE.

         The Company shall have designated Chase Bank of Texas, National
Association (or other U.S. bank or trust company reasonably acceptable to you)
to act as Trustee pursuant to the Trust Indenture and Chase Bank of Texas,
National Association (or other U.S. bank or trust company reasonably acceptable
to you), shall have accepted such appointment and said Trustee shall have
delivered to you (a) a certificate of its secretary or an assistant secretary
certifying as to its articles of association and bylaws, resolutions or other
authority to act as Trustee and the incumbency of officers, and (b) a good
standing certificate from the Comptroller of the Currency.

                                       -7-


<PAGE>   13



4.20.    AGENT FOR SERVICE OF PROCESS.

         You shall have received, in form and substance satisfactory to you,
evidence of the consent of CT Corporation in New York, New York to the
appointment and designation as Agent for service of process for the Company and
Noble US in accordance with the Credit Documents, such evidence in the case of
Noble US to be as of the date hereof, and such evidence in the case of the
Company to be for the period from the Closing through March 16, 2004.

4.21.    FILING OF DOCUMENTS.

         On or before the Purchase Date, (a) the First Naval Mortgage shall have
been filed in the appropriate office under Panamanian law, and (b) Uniform
Commercial Code financing statements reflecting the Company as debtor and the
Trustee as secured party shall have been filed in the appropriate public
offices.

5.       REPRESENTATIONS AND WARRANTIES OF THE COMPANY.

         The Company represents and warrants to you that:

5.1.     ORGANIZATION; POWER AND AUTHORITY.

         Each of the Company and Noble US is a corporation duly organized,
validly existing and in good standing under the laws of its jurisdiction of
incorporation, and is duly qualified as a foreign corporation and is in good
standing in each jurisdiction in which such qualification is required by law,
other than those jurisdictions as to which the failure to be so qualified or in
good standing would not, individually or in the aggregate, reasonably be
expected to have a Material Adverse Effect. Each of the Company and Noble US has
the corporate power and authority to own or hold under lease the properties it
purports to own or hold under lease, to transact the business it transacts and
proposes to transact, to execute and deliver this Agreement and the Other
Agreements, the Notes and the other Credit Documents to which it is a party and
to perform the provisions hereof and thereof.

5.2.     AUTHORIZATION, ETC.

         This Agreement and the Other Agreements, the Notes and the other Credit
Documents have been duly authorized by all necessary corporate action on the
part of the Company and Noble US, and this Agreement and the other Credit
Documents constitute, and upon execution and delivery thereof each Note will
constitute, a legal, valid and binding obligation of the Company and/or Noble US
enforceable against the Company and/or Noble US in accordance with its terms,
except as such enforceability may be limited by (i) applicable bankruptcy,
insolvency, reorganization, moratorium or other similar laws affecting the
enforcement of creditors' rights generally and (ii) general principles of equity
(regardless of whether such enforceability is considered in a proceeding in
equity or at law).


                                       -8-


<PAGE>   14



5.3.     DISCLOSURE.

         The Company, through its agent, BTM Financial Services, Inc., has
delivered to you and each Other Purchaser a copy of a Confidential Offering
Memorandum, dated April 1998 (the "MEMORANDUM"), relating to the transactions
contemplated hereby. Except as disclosed in Schedule 5.3, this Agreement, the
Memorandum, the documents, certificates or other writings identified in Schedule
5.3 and the financial statements referred to in Section 5.5, and each other
statement by the Company taken as a whole, do not contain any untrue statement
of a material fact or omit to state any material fact necessary to make the
statements therein not misleading in light of the circumstances under which they
were made. Except as disclosed in the Memorandum or as expressly described in
Schedule 5.3, or in one of the documents, certificates or other writings
identified therein, or in the financial statements referred to in Section 5.5,
since December 31, 1997, there has been no change in the financial condition,
operations, business or properties of Noble US, Noble Corp., or the Company
except changes that individually or in the aggregate would not reasonably be
expected to have a Material Adverse Effect.

5.4.     ORGANIZATION AND OWNERSHIP OF BORROWER AND NOBLE US.

         (a) Noble US is a wholly owned subsidiary of Noble Corp.

         (b) The Company is a single purpose wholly owned subsidiary of Noble
US.

5.5.     FINANCIAL STATEMENTS.

         (a) The unaudited consolidated balance sheets as of December 31, 1993,
1994, 1995, 1996 and 1997 and the unaudited consolidated statements of
operations for each of the years in the five-year period ended December 31, 1997
of Noble US and its Subsidiaries, copies of which are contained in Exhibit F to
the Memorandum, fairly present in all material respects the consolidated
financial position of Noble US and its Subsidiaries as of such dates and the
consolidated results of their operations for such years and have been prepared
in accordance with GAAP (exclusive of footnotes) consistently applied throughout
the periods involved.

         (b) The unaudited proforma statements of cash flow of the Company
contained in Exhibit J to the Memorandum have been prepared on a reasonable
basis.

         (c) The audited consolidated balance sheets as of December 31, 1995,
1996 and 1997 and the audited consolidated statements of operations for each of
the years in the three-year period ended December 31, 1997 of Noble Corp. and
its Subsidiaries, copies of which have been furnished to you, fairly present in
all material respects the consolidated financial position of Noble Corp. and its
Subsidiaries as of such dates and the consolidated results of their operations
for such years and have been prepared in accordance with GAAP consistently
applied throughout the periods involved.

5.6.     COMPLIANCE WITH LAWS, OTHER INSTRUMENTS, ETC.

         The execution, delivery and performance by the Company of this
Agreement, the Notes and the other Credit Documents to which it is a party and
by Noble US of the Credit Documents to which

                                       -9-


<PAGE>   15



it is a party will not (i) contravene, result in any breach of, or constitute a
default under, or result in the creation of any Lien in respect of any property
of the Company, Noble US or any Subsidiary under, any indenture, mortgage, deed
of trust, loan, purchase or credit agreement, lease, corporate charter or
by-laws, or any other Material agreement or instrument to which the Company or
Noble US or any Subsidiary thereof is bound or by which the Company or Noble US
or any Subsidiary thereof or any of their respective properties may be bound or
affected, (ii) conflict with or result in a breach of any of the terms,
conditions or provisions of any order, judgment, decree, or ruling of any court,
arbitrator or Governmental Authority applicable to the Company or Noble US or
any Subsidiary thereof or (iii) violate any provision of any statute or other
rule or regulation of any Governmental Authority applicable to the Company or
Noble US or any Subsidiary thereof.

5.7.     GOVERNMENTAL AUTHORIZATIONS, ETC.

         Except as specified in Schedule 5.7, no consent, approval or
authorization of, or registration, filing or declaration with, any Governmental
Authority is required in connection with the execution, delivery or performance
by the Company or Noble US of this Agreement, the Notes or the other Credit
Documents.

5.8.     LITIGATION; OBSERVANCE OF STATUTES AND ORDERS.

         (a) Except as disclosed in Schedule 5.8, there are no actions, suits or
proceedings pending or, to the knowledge of the Company, threatened against or
affecting the Company Noble US or Noble Corp. or any property of the Company,
Noble US or Noble Corp. in any court or before any arbitrator of any kind or
before or by any Governmental Authority that, individually or in the aggregate,
would reasonably be expected to have a Material Adverse Effect.

         (b) Neither the Company nor Noble US nor Noble Corp. is in default
under any order, judgment, decree or ruling of any court, arbitrator or
Governmental Authority or is in violation of any applicable law, ordinance, rule
or regulation (including without limitation Environmental Laws) of any
Governmental Authority, which default or violation, individually or in the
aggregate, would reasonably be expected to have a Material Adverse Effect.

5.9.     TAXES.

         Noble Corp. has filed all income tax returns that are required to have
been filed in any jurisdiction, and paid all taxes shown to be due and payable
on such returns and all other taxes and assessments payable by it, to the extent
such taxes and assessments have become due and payable and before they have
become delinquent, except for any taxes and assessments the amount of which is
not individually or in the aggregate Material to Noble Corp. and its
Subsidiaries on a consolidated basis and to the extent assessed against Noble US
or the Company, Material to Noble US or the Company or the amount, applicability
or validity of which is currently being contested in good faith by appropriate
proceedings and with respect to which Noble Corp. and its Subsidiaries, on a
consolidated basis, the Company or Noble US, as the case may be, has established
adequate reserves including but not limited to those required in accordance with
GAAP.


                                      -10-


<PAGE>   16



5.10.    TITLE TO PROPERTY.

         The Company and Noble US have good and indefeasible title to their
respective Material properties, including all such properties reflected in the
most recent balance sheet referred to in Section 5.5 or purported to have been
acquired by the Company or Noble US after said date (except as sold or otherwise
disposed of in the ordinary course of business) including, without limitation
the Drilling Rig, in each case free and clear of Liens other than Excepted
Liens, which in the case of the Drilling Rig are not in an aggregate amount in
excess of $5,000,000. All Material leases are valid and subsisting and are in
full force and effect in all Material respects.

5.11.    LICENSES, PERMITS, ETC.

         (a) Except as disclosed in Schedule 5.11, the Company and Noble US own
or possess all licenses, permits, franchises, authorizations, patents,
copyrights, service marks, trademarks and trade names, or rights thereto, that
are Material, without known conflict with the rights of others.

         (b) The Company owns or possesses all licenses, permits, franchises,
authorizations, patents, copyrights, service marks, trademarks and trade names,
or rights thereto, without any known conflict with the rights of others,
necessary to own and operate the Drilling Rig and perform the Shell Contract as
contemplated therein.

5.12.    COMPLIANCE WITH ERISA.

         The Company has no Plan and makes no contributions to any Plan. With
respect to any Plan which is or at any time within the past five years has been
sponsored, maintained or contributed to by any ERISA Affiliate:

         (a) The Company and each ERISA Affiliate have operated and administered
such Plan in compliance with all applicable laws except for such instances of
noncompliance as have not resulted in and could not reasonably be expected to
result in a Material Adverse Effect. Neither the Company nor any ERISA Affiliate
has incurred any liability pursuant to Title I or IV of ERISA or the penalty or
excise tax provisions of the Code relating to employee benefit plans (as defined
in Section 3 of ERISA), and no event, transaction or condition has occurred or
exists that would reasonably be expected to result in the incurrence of any such
liability by the Company or any ERISA Affiliate, or in the imposition of any
Lien on any of the rights, properties or assets of the Company or any ERISA
Affiliate, in either case pursuant to Title I or IV of ERISA or to such penalty
or excise tax provisions or to Section 401(a)(29) or 412 of the Code, other than
such liabilities or Liens as would not be individually or in the aggregate
Material.

         (c) The present value of the aggregate benefit liabilities under each
such Plan (other than Multiemployer Plans), determined as of the end of such
Plan's most recently ended plan year on the basis of the actuarial assumptions
specified for funding purposes in such Plan's most recent actuarial valuation
report, did not exceed the aggregate current value of the assets of such Plan
allocable to such benefit liabilities by more than $10,000,000 in the case of
any single Plan and by more than $25,000,000 in the aggregate for all Plans. The
term "BENEFIT LIABILITIES" has the meaning specified

                                      -11-


<PAGE>   17



in section 4001 of ERISA and the terms "CURRENT VALUE" and "PRESENT VALUE" have
the meaning specified in section 3 of ERISA.

         (d) None of the Company, Noble US or the ERISA Affiliates have incurred
withdrawal liabilities (or are subject to contingent withdrawal liabilities)
under section 4201 or 4204 of ERISA in respect of Multiemployer Plans that
individually or in the aggregate are Material.

         (e) The expected postretirement benefit obligation (determined as of
December 31, 1997 in accordance with Financial Accounting Standards Board
Statement No. 106, without regard to liabilities attributable to continuation
coverage mandated by section 4980B of the Code) of the Company and its ERISA
Affiliates is not Material.

         (f) The execution and delivery of this Agreement and the other Credit
Documents and the issuance and sale of the Notes hereunder will not involve any
transaction that is subject to the prohibitions of section 406 of ERISA or in
connection with which a tax could be imposed pursuant to section
4975(c)(1)(A)-(D) of the Code. The representation by the Company in the first
sentence of this Section 5.12(f) is made in reliance upon and subject to the
accuracy of your representation in Section 6.2 as to the sources of the funds to
be used to pay the purchase price of the Notes to be purchased by you.

5.13.    PRIVATE OFFERING BY THE COMPANY.

         Neither the Company nor anyone acting on its behalf has offered the
Notes or any similar securities for sale to, or solicited any offer to buy any
of the same from, or otherwise approached or negotiated in respect thereof with,
any person other than you, the Other Purchasers and not more than 35 other
Institutional Investors, each of which has been offered the Notes at a private
sale for investment. Neither the Company nor anyone acting on its behalf has
taken, or will take, any action that would subject the issuance or sale of the
Notes to the registration requirements of Section 5 of the Securities Act.

5.14.    USE OF PROCEEDS; MARGIN REGULATIONS.

         The Company will apply the proceeds of the sale of the Notes to (i)
fund the Debt Service Reserve Fund, (ii) fund the Working Capital Fund with at
least $1,950,000, (iii) repay loans owing to Noble US or an Affiliate thereof
incurred as part of the cost of conversion of the Drilling Rig to a Noble
Drilling EVA-4000 (tm) semisubmersible fourth generation drilling rig, and (iv)
provide one or more advances or dividends to Noble US. No part of the proceeds
from the sale of the Notes hereunder will be used, directly or indirectly, for
the purpose of buying or carrying any margin stock within the meaning of
Regulation U of the Board of Governors of the Federal Reserve System (12 CFR
221), or for the purpose of buying or carrying or trading in any securities
under such circumstances as to involve the Company or Noble US or any of its
Subsidiaries in a violation of Regulation X of said Board (12 CFR 224) or to
involve any broker or dealer in a violation of Regulation T of said Board (12
CFR 220). As used in this Section, the terms "MARGIN STOCK" and "PURPOSE OF
BUYING OR CARRYING" shall have the meanings assigned to them in said Regulation
U. The Company does not own and will not acquire any margin stock.


                                      -12-


<PAGE>   18



5.15.    DEBT.

         (a) The Company has no Debt as of the date hereof other than loans
owing to Noble US or an Affiliate thereof which will be paid in full with
proceeds of the sale of the Notes as provided in Section 5.14 above, and it will
have no Debt (other than Debt represented by the Notes) on the date of Closing.

         (b) Since June 30, 1998, there has been no Material change in the
amounts, interest rates, sinking funds, installment payments or maturities of
the Debt reflected on the financial statements of Noble US as of such date
(copies of which have been delivered to you). Neither Noble US nor any
Subsidiary is in default and no waiver of default is currently in effect, in the
payment of any principal or interest on any Debt of Noble US or such Subsidiary.
No event or condition exists with respect to any Debt of Noble US or any
Subsidiary the outstanding principal amount of which exceeds $1,000,000 that
would permit (or that with notice or the lapse of time, or both, would permit)
one or more Persons to cause such Debt to become due and payable before its
stated maturity or before its regularly scheduled dates of payment.

5.16.    FOREIGN ASSETS CONTROL REGULATIONS, ETC.

         Neither the sale of the Notes by the Company hereunder nor its use of
the proceeds thereof will violate the Trading with the Enemy Act, as amended, or
any of the foreign assets control regulations of the United States Treasury
Department (31 CFR, Subtitle B, Chapter V, as amended) or any enabling
legislation or executive order relating thereto.

5.17.    STATUS UNDER CERTAIN STATUTES.

         Neither the Company nor any Affiliate thereof is subject to regulation
under the Investment Company Act of 1940, as amended, the Public Utility Holding
Company Act of 1935, as amended, the Interstate Commerce Act, as amended, or the
Federal Power Act, as amended.

5.18.    SUBSIDIARIES.

         The Company has no Subsidiaries.

5.19.    NATURE OF BUSINESS AND LOCATION OF BUSINESS AND OFFICES.

         The Company is organized for the single purpose of owning and operating
the Drilling Rig and does not engage directly or indirectly in any other
business. The Company's principal place of business and chief executive offices
are located at the address stated for the Company at the beginning of this
Agreement.


                                      -13-


<PAGE>   19



5.20.    ENVIRONMENTAL MATTERS.

          Except (i) as provided in Schedule 5.20 or (ii) as could not have a
Material Adverse Effect (or with respect to (c), (d) and (e) below, where the
failure to take such actions would not have a Material Adverse Effect):

                  (a) Neither any Property of the Company nor Noble US nor any
         Subsidiary nor the operations conducted thereon violate any order or
         requirement of any court or Governmental Authority or any Environmental
         Laws;

                  (b) Without limitation of clause (a) above, no Property of the
         Company, Noble US or any Subsidiary nor the operations currently
         conducted thereon or, to the knowledge of the Company, by any prior
         owner or operator of such Property or operation, are in violation of or
         subject to any existing, pending or threatened action, suit,
         investigation, inquiry or proceeding by or before any court or
         Governmental Authority or to any remedial obligations under
         Environmental Laws;

                  (c) All notices, permits, licenses or similar authorizations,
         if any, required to be obtained or filed in connection with the
         operation or use of any and all Property of the Company, Noble US and
         each Subsidiary, including without limitation past or present
         treatment, storage, disposal or release of a hazardous substance or
         solid waste into the environment, have been duly obtained or filed, and
         the Company, Noble US and each Subsidiary are in compliance with the
         terms and conditions of all such notices, permits, licenses and similar
         authorizations;

                  (d) All hazardous substances, solid waste, and oil and gas
         exploration and production wastes, if any, generated at any and all
         Property owned or leased by the Company, Noble US or any Subsidiary
         have in the past been transported, treated and disposed of in
         accordance with Environmental Laws and so as not to pose an imminent
         and substantial endangerment to public health or welfare or the
         environment, and, to the knowledge of the Company, all such transport
         carriers and treatment and disposal facilities have been and are
         operating in compliance with Environmental Laws and so as not to pose
         an imminent and substantial endangerment to public health or welfare or
         the environment, and are not the subject of any existing, pending or
         threatened action, investigation or inquiry by any Governmental
         Authority in connection with any Environmental Laws;

                  (e) The Company and Noble US have taken all steps reasonably
         necessary to determine and has determined that no hazardous substances,
         solid waste, or oil and gas exploration and production wastes, have
         been disposed of or otherwise released and there has been no threatened
         release of any hazardous substances on or to any Property of the
         Company, Noble US or any Subsidiary except in compliance with
         Environmental Laws and so as not to pose an imminent and substantial
         endangerment to public health or welfare or the environment;

                  (f) To the extent applicable, all Property of the Company,
         Noble US and each Subsidiary currently satisfies all design, operation,
         and equipment requirements imposed by

                                      -14-


<PAGE>   20



         the OPA or scheduled as of the date of the Closing to be imposed by OPA
         during the term of this Agreement, and the Company does not have any
         reason to believe that such Property, to the extent subject to OPA,
         will not be able to maintain compliance with the OPA requirements
         during the term of this Agreement; and

                  (g) Neither the Company, Noble US nor any Subsidiary has any
         known contingent liability in connection with any release or threatened
         release of any oil, hazardous substance or solid waste into the
         environment.

5.21.    SHELL CONTRACT.

         The copies of the Shell Contract previously delivered by the Company to
you are complete and accurate and have not been amended or modified in any
manner except as permitted by Section 7.3(d) of the Trust Indenture. The Shell
Contract is valid, binding and enforceable against the parties thereto.

5.22.    NO INDENTURE DEFAULTS.

         No event has occurred and is continuing and no condition exists which,
upon the issuance of the Notes, would constitute an Indenture Default or an
Indenture Event of Default. Neither the Company nor Noble US is in violation in
any respect of any term of its certificate of incorporation or bylaws, and
neither the Company nor Noble US is in violation of any material term in any
Material agreement or other Material instrument to which it is a party or by
which it or any of its Property may be bound. Except for the Credit Documents
and the Shell Contract, there are no Material agreements or Material instruments
to which the Company is a party or by which it or any of its Property is bound.

5.23.    RIG CLASSIFICATION.

         As of the Purchase Date, the Drilling Rig will be classified in the
highest class available for rigs of its age and type with the American Bureau of
Shipping, free of any material requirements or recommendations.

5.24.    INSURANCE.

         As of the Purchase Date, the Drilling Rig is covered by the insurance
required by Section 2.13 of the First Naval Mortgage and such insurance is in
full force and effect and all premiums due in respect of such insurance have
been paid.

5.25.    SECURITY INTERESTS.

         On the Purchase Date, (a) the Drilling Rig will be duly documented in
the name of the Company under the laws of Panama, and no other filing,
recordation or registration of any other document or instrument will be
necessary in order to establish the Company's good and valid title to the
Drilling Rig, and (b) all filings necessary or desirable to perfect the first
Lien and security interest of the Trustee under the Trust Indenture in the Trust
Estate as against creditors of and

                                      -15-


<PAGE>   21



purchasers from the Company will have been duly made, and the Trust Indenture
will on the Purchase Date create a valid and perfected first priority lien and
security interest in the Trust Estate, effective as against creditors of and
purchasers from the Company, securing all obligations secured thereby, except
that the First Naval Mortgage must, within six months after being particularly
recorded through the Panamanian Consul in Houston, Texas, be permanently
recorded at the Public Registry Office of the Republic of Panama.

5.26.    YEAR 2000.

         The Company, through its Affiliates, has taken appropriate steps to
assess, quantify, address and resolve its business and financial risks resulting
from the Year 2000 Problem, including those business and economic risks
resulting from the failure of key suppliers, vendors and customers of the
Company to properly assess, quantify, address and resolve the Year 2000 Problem.
Based on that review, the Company does not believe that the Year 2000 Problem or
the costs of implementing a comprehensive program to address the Year 2000
Problem will result in a Material Adverse Effect.

5.27.    SDDI ACKNOWLEDGMENT AND CONSENT.

         The provisions set forth in the second sentence of the fourth paragraph
of the SDDI Acknowledgment and Consent do not permit the Company and SDDI to
decrease the dayrate specified in the Shell Contract.

6.       REPRESENTATIONS OF THE PURCHASER.

6.1.     PURCHASE FOR INVESTMENT.

         You represent that you are purchasing the Notes for your own account or
for one or more separate accounts maintained by you or for the account of one or
more pension or trust funds and not with a view to the distribution thereof,
provided that the disposition of your or their property shall at all times be
within your or their control. You understand that the Notes have not been
registered under the Securities Act and may be resold only if registered
pursuant to the provisions of the Securities Act or if an exemption from
registration is available and that the Company is not required to register the
Notes.

6.2.     SOURCE OF FUNDS.

         You represent that at least one of the following statements is an
accurate representation as to each source of funds (a "SOURCE") to be used by
you to pay the purchase price of the Notes to be purchased by you hereunder:

                  (a) if you are an insurance company, the Source does not
         include assets allocated to any separate account maintained by you in
         which any employee benefit plan (or its related trust) has any
         interest, other than a separate account that is maintained solely in
         connection with your fixed contractual obligations under which the
         amounts payable, or credited, to such plan and to any participant or
         beneficiary of such plan (including any annuitant) are not affected in
         any manner by the investment performance of the separate account; or

                                      -16-


<PAGE>   22



                  (b) if you are an insurance company, to the extent that the
         Source constitutes assets allocated to any general account maintained
         by you, there is no employee benefit plan with respect to which the
         amount, if any, of such general account's reserves and liabilities for
         all contracts held by or on behalf of such plan and all other plans
         maintained by the same employer or its affiliates or by the same
         employee organization exceeds 10% of the total of all reserves and
         liabilities of such general account at the date of purchase (all as
         determined under Prohibited Transaction Class Exemption ("PTE") 95-60
         (issued July 12, 1995)); or

                  (c) the Source is either (i) an insurance company pooled
         separate account, within the meaning of PTE 90-1 (issued January 29,
         1990), or (ii) a bank collective investment fund, within the meaning of
         the PTE 91-38 (issued July 12, 1991) and, except as you have disclosed
         to the Company in writing pursuant to this paragraph (c), no employee
         benefit plan or group of plans maintained by the same employer or
         employee organization beneficially owns more than 10% of all assets
         allocated to such pooled separate account or collective investment
         fund; or

                  (d) the Source constitutes assets of an "INVESTMENT FUND"
         (within the meaning of Part V of the QPAM Exemption) managed by a
         "QUALIFIED PROFESSIONAL ASSET MANAGER" or "QPAM" (within the meaning of
         Part V of the QPAM Exemption), no employee benefit plan's assets that
         are included in such investment fund, when combined with the assets of
         all other employee benefit plans established or maintained by the same
         employer or by an affiliate (within the meaning of Section V(c)(1) of
         the QPAM Exemption) of such employer or by the same employee
         organization and managed by such QPAM, exceed 20% of the total client
         assets managed by such QPAM, the conditions of Part I(c) and (g) of the
         QPAM Exemption are satisfied, neither the QPAM nor a person controlling
         or controlled by the QPAM (applying the definition of "CONTROL" in
         Section V(e) of the QPAM Exemption) owns a 5% or more interest in the
         Company and (i) the identity of such QPAM and (ii) the names of all
         employee benefit plans whose assets are included in such investment
         fund have been disclosed to the Company in writing pursuant to this
         paragraph (d); or

                  (e) the Source is a governmental plan; or

                  (f) the Source does not include assets of any employee benefit
         plan, other than a plan exempt from the coverage of ERISA; or

                  (g) the Source is one or more employee benefit plans, or a
         separate account, general account or trust fund comprised of one or
         more employee benefit plans, each of which has been identified to the
         Company in writing pursuant to this paragraph (g).

As used in this Section 6.2, the terms "EMPLOYEE BENEFIT PLAN", "GOVERNMENTAL
PLAN", "PARTY IN INTEREST" and "SEPARATE ACCOUNT" shall have the respective
meanings assigned to such terms in Section 3 of ERISA.


                                      -17-


<PAGE>   23



7.       EXPENSES, ETC.

7.1.     TRANSACTION EXPENSES.

         Whether or not the transactions contemplated hereby are consummated,
the Company will pay all costs and expenses, including the cost of obtaining the
Private Placement Number, reasonable attorneys' fees of a special external
counsel and, if reasonably required, local or other counsel (provided that to
the extent it is feasible and a conflict of interest does not exist in the
reasonable discretion of the Note holders, the holders of the Series A Notes
shall use the same counsel and the holders of the Series B Notes shall use the
same counsel) incurred by you and each Other Purchaser or holder of a Note in
connection with such transactions and in connection with any amendments, waivers
or consents under or in respect of this Agreement, the Notes and the other
Credit Documents (whether or not such amendment, waiver or consent becomes
effective), including, without limitation: (a) the costs and expenses incurred
in enforcing or defending (or determining whether or how to enforce or defend)
any rights under this Agreement, the Notes or the other Credit Documents or in
responding to any subpoena or other legal process or informal investigative
demand issued in connection with this Agreement, the Notes or the other Credit
Documents, or by reason of being a holder of any Note, and (b) the costs and
expenses, including financial advisors' fees, incurred in connection with the
insolvency or bankruptcy of the Company or Noble US or in connection with any
work-out or restructuring of the transactions contemplated hereby and by the
Notes and the other Credit Documents. The Company will pay, and will save you
and each other holder of a Note harmless from, all claims in respect of any
fees, costs or expenses of (a) the arranger, BTM Financial Services, Inc., (b)
the structuring agent, BTM Capital Corporation, and (c) any other brokers and
finders (other than those retained by you).

7.2.     SURVIVAL.

         The obligations of the Company under this Section 7 will survive the
payment or transfer of any Note, the enforcement, amendment or waiver of any
provision of this Agreement, the Notes or the other Credit Documents, and the
termination of this Agreement.

8.       SURVIVAL OF REPRESENTATIONS AND WARRANTIES.

         All representations and warranties contained herein and in the other
Credit Documents shall survive the execution and delivery of this Agreement, the
Notes and the other Credit Documents, the purchase or transfer by you of any
Note or portion thereof or interest therein and the payment of any Note, and may
be relied upon by any subsequent holder of a Note, regardless of any
investigation made at any time by or on behalf of you or any other holder of a
Note. All statements contained in any certificate or other instrument delivered
by or on behalf of the Company or Noble US pursuant to this Agreement shall be
deemed representations and warranties of the Company under this Agreement.


                                      -18-


<PAGE>   24



9.       AMENDMENT AND WAIVER.

9.1.     REQUIREMENTS.

         Subject to the provisions of the Trust Indenture, this Agreement and
the Notes may be amended, and the observance of any term hereof or of the Notes
may be waived (either retroactively or prospectively), with (and only with) the
written consent of the Company and the Majority Holders, except that (a) no
amendment or waiver of any of the provisions of Section 1, 2, 3, 4, 5, 6 or 13
hereof, or any defined term (as it is used therein), will be effective as to you
unless consented to by you in writing, and (b) no such amendment or waiver may,
without the written consent of the holder of each Note at the time outstanding
affected thereby, (i) change the amount or time of any prepayment or payment of
principal of, or reduce the rate or change the time of payment or method of
computation of interest or of the Make-Whole Amount on, the Notes, (ii) change
the percentage of the principal amount of the Notes the holders of which are
required to consent to any such amendment or waiver, or (iii) amend either
Section 9 or 12.

9.2.     SOLICITATION OF HOLDERS OF NOTES.

         (a) Solicitation. The Company will provide each holder of the Notes
(irrespective of the amount of Notes then owned by it) with sufficient
information, sufficiently far in advance of the date a decision is required, to
enable such holder to make an informed and considered decision, if required,
with respect to any proposed amendment, waiver or consent in respect of any of
the provisions hereof or of the Notes or any other Credit Document. The Company
will deliver executed or true and correct copies of each amendment, waiver or
consent to each holder of outstanding Notes promptly following the date on which
it is executed and delivered by, or receives the consent or approval, if
required, of, the requisite holders of Notes.

         (b) Payment. The Company will not directly or indirectly pay or cause
to be paid any remuneration, whether by way of supplemental or additional
interest, fee or otherwise, or grant any security, to any holder of Notes as
consideration for or as an inducement to the entering into by any holder of
Notes of any waiver or amendment of any of the terms and provisions hereof
unless such remuneration is concurrently paid, or security is concurrently
granted, on the same terms, ratably to each holder of Notes then outstanding
even if such holder did not consent to such waiver or amendment.

9.3.     BINDING EFFECT, ETC.

         Any amendment or waiver consented to as provided in this Section 9 or
effected pursuant to Article 10 of the Trust Indenture applies equally to all
holders of Notes and is binding upon them and upon each future holder of any
Note and upon the Company without regard to whether such Note has been marked to
indicate such amendment or waiver. No such amendment or waiver will extend to or
affect any obligation, covenant, agreement, Indenture Default or Indenture Event
of Default not expressly amended or waived or impair any right consequent
thereon. No course of dealing between the Company and the holder of any Note nor
any delay in exercising any rights hereunder, under any Note or any other Credit
Document shall operate as a waiver of any rights of any holder of such

                                      -19-


<PAGE>   25



Note. As used herein, the term "THIS AGREEMENT" and references thereto shall
mean this agreement as it may from time to time be amended or supplemented.

9.4.     NOTES HELD BY COMPANY, ETC.

         Solely for the purpose of determining whether the holders of the
requisite percentage of the aggregate principal amount of Notes then outstanding
approved or consented to any amendment, waiver or consent to be given under this
Agreement, the Notes or any other Credit Document, or have directed the taking
of any action provided herein or in the Notes or in any other Credit Document to
be taken upon the direction of the holders of a specified percentage of the
aggregate principal amount of Notes then outstanding, Notes directly or
indirectly owned by the Company or any of its Affiliates shall be deemed not to
be outstanding.

10.      NOTICES.

         All notices and communications provided for hereunder shall be in
writing and sent (a) by facsimile (with a copy sent by registered or certified
mail on the same date), or (b) by registered or certified mail with return
receipt requested (postage prepaid), or (c) by a recognized overnight delivery
service (with charges prepaid). Any such notice must be sent:

                  (i) if to you or your nominee, to you or it at the address
         specified for such communications in Schedule A, or at such other
         address as you or it shall have specified to the Company in writing,

                  (ii) if to any other holder of any Note, to such holder at
         such address as such other holder shall have specified to the Company
         in writing, or

                  (iii) if to the Company, to the Company at its address set
         forth at the beginning hereof to the attention of President, or at such
         other address as the Company shall have specified to the holder of each
         Note in writing.

Notices under this Section 10 will be deemed given only when actually received.

11.      REPRODUCTION OF DOCUMENTS.

         This Agreement and all documents relating thereto, including, without
limitation, (a) consents, waivers and modifications that may hereafter be
executed, (b) documents received by you at the Closing (except the Notes
themselves), and (c) financial statements, certificates and other information
previously or hereafter furnished to you, may be reproduced by you by any
photographic, photostatic, microfilm, microcard, miniature photographic or other
similar process and you may destroy any original document so reproduced. The
Company agrees and stipulates that, to the extent permitted by applicable law,
any such reproduction shall be admissible in evidence as the original itself in
any judicial or administrative proceeding (whether or not the original is in
existence and whether or not such reproduction was made by you in the regular
course of business) and any enlargement, facsimile or further reproduction of
such reproduction shall likewise be admissible in evidence. This Section 11
shall not prohibit the Company or any other holder of Notes from

                                      -20-


<PAGE>   26



contesting any such reproduction to the same extent that it could contest the
original, or from introducing evidence to demonstrate the inaccuracy of any such
reproduction.

12.      CONFIDENTIAL INFORMATION.

         For the purposes of this Section 12, "CONFIDENTIAL INFORMATION" means
written information delivered to you by or on behalf of the Company or Noble US
in connection with the transactions contemplated by or otherwise pursuant to
this Agreement that is proprietary in nature and that was clearly marked or
labeled or otherwise adequately identified when received by you as being
confidential information of the Company or Noble US, provided that such term
does not include information that (a) was publicly known or otherwise known to
you prior to the time of such disclosure, (b) subsequently becomes publicly
known through no act or omission by you or any person acting on your behalf, (c)
otherwise becomes known to you other than through disclosure by the Company or
Noble US or (d) constitutes financial statements delivered to you under the
provisions of this Agreement or the Trust Indenture that are otherwise publicly
available. You will maintain the confidentiality of such Confidential
Information in accordance with procedures adopted by you in good faith and
pursuant to prudent business practices to protect confidential information of
third parties delivered to you, provided that you may deliver or disclose
Confidential Information to (i) your directors, officers, employees, agents,
attorneys and Affiliates (to the extent such disclosure reasonably relates to
the administration of the investment represented by your Notes), (ii) your
financial advisors and other professional advisors who agree to hold
confidential the Confidential Information substantially in accordance with the
terms of this Section 12, (iii) any other holder of any Note, (iv) any
Institutional Investor to which you sell or offer to sell such Note or any part
thereof or any participation therein (if such Person has agreed in writing prior
to its receipt of such Confidential Information to be bound by the provisions of
this Section 12), (v) any Person from which you offer to purchase any security
of the Company (if such Person has agreed in writing prior to its receipt of
such Confidential Information to be bound by the provisions of this Section 12),
(vi) any federal or state regulatory authority having jurisdiction over you,
(vii) the National Association of Insurance Commissioners or any similar
organization, or any nationally recognized rating agency that requires access to
information about your investment portfolio, (viii) any Credit Support Party or
(ix) any other Person to which such delivery or disclosure may be necessary or
appropriate (w) to effect compliance with any law, rule, regulation or order
applicable to you, (x) in response to any subpoena or other legal process, (y)
in connection with any litigation to which you are a party or (z) if an
Indenture Event of Default has occurred and is continuing, to the extent you may
reasonably determine such delivery and disclosure to be necessary or appropriate
in the enforcement or for the protection of the rights and remedies under your
Notes, this Agreement and the other Credit Documents. Each holder of a Note, by
its acceptance of a Note, will be deemed to have agreed to be bound by and to be
entitled to the benefits of this Section 12 as though it were a party to this
Agreement. On reasonable written request by the Company, in connection with the
delivery to any holder of a Note of information required to be delivered to such
holder under this Agreement or requested by such holder (other than a holder
that is a party to this Agreement or its nominee), such holder will enter into
an agreement with the Company embodying the provisions of this Section 12.


                                      -21-


<PAGE>   27



13.      SUBSTITUTION OF PURCHASER.

         You shall have the right to substitute any one of your Affiliates as
the purchaser of the Notes that you have agreed to purchase hereunder, by
written notice to the Company, which notice shall be signed by both you and such
Affiliate, shall contain such Affiliate's agreement to be bound by this
Agreement expressly including Section 12 hereof and shall contain a confirmation
by such Affiliate of the accuracy with respect to it of the representations set
forth in Section 6. Upon receipt of such notice, wherever the word "YOU" is used
in this Agreement (other than in this Section 13), such word shall be deemed to
refer to such Affiliate in lieu of you. In the event that such Affiliate is so
substituted as a purchaser hereunder and such Affiliate thereafter transfers to
you all of the Notes then held by such Affiliate, upon receipt by the Company of
notice of such transfer, wherever the word "you" is used in this Agreement
(other than in this Section 13), such word shall no longer be deemed to refer to
such Affiliate, but shall refer to you, and you shall have all the rights of an
original holder of the Notes under this Agreement.

14.      MISCELLANEOUS.

14.1.    SUCCESSORS AND ASSIGNS.

         Whenever any of the parties hereto is referred to, such reference shall
be deemed to include the successors and assigns of such party; and all the
covenants, promises and agreements in this Agreement contained by or on behalf
of the Company or by or on behalf of you, shall bind and inure to the benefit of
the respective successors and assigns of such parties whether so expressed or
not; provided; however, that the Company shall not assign or transfer any of its
rights or delegate any of its duties or obligations hereunder without the prior
written consent of all of the holders of the Notes.

14.2.    PAYMENTS DUE ON NON-BUSINESS DAYS.

         Anything in this Agreement or the Notes to the contrary
notwithstanding, any payment of principal of or Make-Whole Amount or interest on
any Note that is due on a date other than a Business Day shall be made on the
next succeeding Business Day without including the additional days elapsed in
the computation of the interest payable on such next succeeding Business Day
(interest for such additional days to accrue and be payable on the next
regularly scheduled payment date).

14.3.    SEVERABILITY.

         Any provision of this Agreement that is prohibited or unenforceable in
any jurisdiction shall, as to such jurisdiction, be ineffective to the extent of
such prohibition or unenforceability without invalidating the remaining
provisions hereof, and any such prohibition or unenforceability in any
jurisdiction shall (to the full extent permitted by law) not invalidate or
render unenforceable such provision in any other jurisdiction.

14.4.    CONSTRUCTION.


                                      -22-


<PAGE>   28



         Each covenant contained herein shall be construed (absent express
provision to the contrary) as being independent of each other covenant contained
herein, so that compliance with any one covenant shall not (absent such an
express contrary provision) be deemed to excuse compliance with any other
covenant. Where any provision herein refers to action to be taken by any Person,
or which such Person is prohibited from taking, such provision shall be
applicable whether such action is taken directly or indirectly by such Person.

14.5.    COUNTERPARTS.

         This Agreement may be executed in any number of counterparts, each of
which shall be an original but all of which together shall constitute one
instrument. Each counterpart may consist of a number of copies hereof, each
signed by less than all, but together signed by all, of the parties hereto.

14.6.    GOVERNING LAW.

         THIS AGREEMENT (INCLUDING, BUT NOT LIMITED TO, THE VALIDITY AND
ENFORCEABILITY HEREOF) SHALL BE GOVERNED BY, AND CONSTRUED IN ACCORDANCE WITH,
THE LAWS OF THE STATE OF NEW YORK, OTHER THAN CONFLICT OF LAWS RULES THEREOF
THAT WOULD REQUIRE THE APPLICATION OF THE LAWS OF A JURISDICTION OTHER THAN SUCH
STATE.

14.7.    FINAL AGREEMENT.

         THIS AGREEMENT AND THE OTHER CREDIT DOCUMENTS EMBODY THE ENTIRE
AGREEMENT AND UNDERSTANDING BETWEEN THE PARTIES AND SUPERSEDE ALL OTHER
AGREEMENTS AND UNDERSTANDINGS BETWEEN SUCH PARTIES RELATING TO THE SUBJECT
MATTER HEREOF AND THEREOF. THE CREDIT DOCUMENTS REPRESENT THE FINAL AGREEMENT
BETWEEN THE PARTIES AND MAY NOT BE CONTRADICTED BY EVIDENCE OF PRIOR,
CONTEMPORANEOUS OR SUBSEQUENT ORAL AGREEMENTS OF THE PARTIES. THERE ARE NO
UNWRITTEN ORAL AGREEMENTS BETWEEN THE PARTIES.


                                    * * * * *



                                      -23-


<PAGE>   29



         If you are in agreement with the foregoing, please sign the form of
agreement on the accompanying counterpart of this Agreement and return it to the
Company, whereupon the foregoing shall become a binding agreement between you
and the Company.

                                    Very truly yours,

                                    NOBLE DRILLING (PAUL ROMANO) INC.

                                    By: /s/ BYRON L. WELLIVER
                                       -------------------------------------
                                            Byron L. Welliver
                                            Senior Vice President

The foregoing is hereby
agreed to as of the date
thereof.


BANNER RECEIVABLES CORPORATION


By:       /s/ DOLORES A. BITAR
   -----------------------------------------
              Dolores A. Bitar
              Vice President


                                      -24-


<PAGE>   30



                                                                      SCHEDULE A


                     NAME AND ADDRESS                      PRINCIPAL AMOUNT
                       OF PURCHASER                        OF SERIES A NOTES
                                                           TO BE PURCHASED

NATIONWIDE LIFE AND ANNUITY INSURANCE COMPANY              $5,000,000
One Nationwide Plaza (1-33-07)
Columbus, Ohio 43215-2220
Attention: Corporate Fixed-Income Securities

Payments

All payments on or in respect of the Notes to be by bank wire transfer of
Federal or other immediately available funds (identifying each payment as "Noble
Drilling (Paul Romano) Inc., Senior Secured Notes, Series A, PPN 65504# AA 8,
interest rate, maturity date, principal, premium or interest") to:

         The Bank of New York
         ABA #021-000-018
         BNF: IOC566
         F/A/O Nationwide Life and Annuity Insurance Company
         Attention: P&I Department

Notices

All notices of payment on or in respect of the Notes and written confirmation of
each such payment to:

         Nationwide Life and Annuity Insurance Company
         c/o The Bank of New York
         P. O. Box 19266
         Newark, New Jersey 07195
         Attention: P&I Department

With a copy to:

         Nationwide Life and Annuity Insurance Company
         One Nationwide Plaza (1-32-05)
         Columbus, Ohio 43215-2220
         Attention: Investment Accounting

All notices and communications other than those in respect to payments to be
addressed as first provided above.

Name of Nominee in which Notes are to be issued: None

Taxpayer I.D. Number: 31-1000740

                                   Schedule A


<PAGE>   31




                     NAME AND ADDRESS                      PRINCIPAL AMOUNT
                       OF PURCHASER                        OF SERIES A NOTES
                                                           TO BE PURCHASED

LINCOLN NATIONAL HEALTH & CASUALTY                         $1,912,500
  INSURANCE COMPANY
c/o Lincoln Investment Management, Inc.
200 East Berry Street
Renaissance Square
Fort Wayne, Indiana 46802
Attention: Investments/Private Placements
Fax:     (212) 455-5499 Private Placements

Payments

All payments on or in respect of the Notes to be by bank wire transfer of
Federal or other immediately available funds (identifying each payment as "Noble
Drilling (Paul Romano) Inc., Senior Secured Notes, Series A, PPN 65504# AA 8,
interest rate, maturity date, principal, premium or interest") to:

         Chase Manhattan Bank
         New York, New York
         ABA #021000021
         CHASE NYC/CTR/BNF
         A/C #900-9-000200

         Further Credit: Lincoln National Health & Casualty Insurance Company
         Custody Account Number: G06323

Notices

All notices and communications, including notices with respect to payments and
written confirmation of each such payment, to be addressed as first provided
above with duplicate notices with respect to payments to:

         Chase Manhattan Bank, N.A.
         Private Placement Servicing
         P. O. Box 1508
         Bowling Green Station
         New York, New York 10081
         Fax: (212) 623-6422 Private Placements

Name of Nominee in which Notes are to be issued: None

Taxpayer I.D. Number: 35-1495207


                                   Schedule A


<PAGE>   32






                     NAME AND ADDRESS                      PRINCIPAL AMOUNT
                       OF PURCHASER                        OF SERIES A NOTES
                                                           TO BE PURCHASED

TEACHERS INSURANCE AND ANNUITY                             $20,000,000
   ASSOCIATION OF AMERICA
730 Third Avenue
New York, New York 10017

Payments

All payments on or in respect of the Note shall be made in immediately available
funds at the opening of business on each due date by electronic funds transfer
(identifying each payment as "Noble Drilling (Paul Romano) Inc., Senior Secured
Notes, Series A, PPN 65504# AA 8, interest rate, maturity date, principal,
premium or interest") through the Automated Clearing House System to:

         The Chase Manhattan Bank
         ABA #021-000-021
         New York, New York
         Account of: TIAA Personal Annuity Private Placements
         Account Number: 900-9-000200
         for further credit to TIA A account #G07320

         Reference:  PPN#/Issuer/Mat.Date/coupon/P&I Breakdown

Notices

Contemporaneous with the above, electronic funds transfer, advise setting forth
(1) the full name, private placement number and coupon of the Note, (2)
allocation of payment between principal, interest, premium and any special
payment, and (3) name and address of Bank (or Trustee) from which wire transfer
was sent, shall be delivered, mailed or faxed to:

         Teachers Insurance and Annuity Association of America
         730 Third Avenue
         New York, New York 10017-3206
         Attention: Securities Accounting Division
         Telephone: (212) 916-4188
         Fax: (212) 916-6955


                                   Schedule A


<PAGE>   33




All other communications shall be delivered or mailed to:

         Teachers Insurance and Annuity Association of America
         730 Third Avenue
         New York, New York 10017-3206
         Attention:  Securities Division
         Telephone:        (212) 916-4164 (Carmen DiSunno) or
                           (212) 490-9000 (General Number)
         Fax: (212) 916-6667 (Team Fax Number)

Name of Nominee in which Notes are to be issued: None

Taxpayer I.D. Number:   13-1624203N



                                   Schedule A


<PAGE>   34





                     NAME AND ADDRESS                      PRINCIPAL AMOUNT
                       OF PURCHASER                        OF SERIES A NOTES
                                                           TO BE PURCHASED

PRINCIPAL LIFE INSURANCE COMPANY                           $15,000,000
711 High Street
Des Moines, Iowa 50392-0800
Attention: Investment Department - Securities
Telefacsimile:    (515) 248-2490
Confirmation:     (515) 248-3494

Payments

All payments on or in respect of the Notes to be by bank wire transfer of
Federal or other immediately available funds (identifying each payment as "Noble
Drilling (Paul Romano) Inc., Senior Secured Notes, Series A, PPN 65504# AA 8,
interest rate, maturity date, principal, premium or interest") to:

         Norwest Bank Iowa, N.A.
         7th and Walnut Streets
         Des Moines, Iowa 50309
         ABA #073000228
         For credit to Principal Life Insurance Company
         Account No.: 0000014752
         OBI: PFGSE(S) B00 61625(  )  Principal $________   Interest $________

Notices

All notices with respect to payments to:

         Principal Life Insurance Company
         711 High Street
         Des Moines, Iowa 50392-0960
         Attention: Investment Accounting - Securities
         Telefacsimile:    (515) 248-2643
         Confirmation:     (515) 247-0689

All other notices and communications to be addressed as first provided above.

Name of Nominee in which Notes are to be issued: None

Taxpayer I.D. Number: 42-0127290



                                   Schedule A


<PAGE>   35






                     NAME AND ADDRESS                      PRINCIPAL AMOUNT
                       OF PURCHASER                        OF SERIES A NOTES
                                                           TO BE PURCHASED

FIRST PENN-PACIFIC LIFE INSURANCE COMPANY                  $4,000,000
c/o Lincoln Investment Management, Inc.
200 East Berry Street
Renaissance Square
Fort Wayne, Indiana 46802
Attention: Investments/Private Placements
Fax:     (219) 455-5499 Private Placements

Payments

All payments on or in respect of the Notes to be by bank wire transfer of
Federal or other immediately available funds (identifying each payment as "Noble
Drilling (Paul Romano) Inc., Senior Secured Notes, Series A, PPN 65504# AA 8,
interest rate, maturity date, principal, premium or interest") to:

         Chase Manhattan Bank
         New York, New York
         ABA #021000021
         A/C #900-9-000200
         Further credit to: G-05996 First Penn-Pacific Life Insurance Company

Notices

All notices and communications, including notices with respect to payments and
written confirmation of each such payment, to be addressed as first provided
above with duplicate notices with respect to payments to:

         Chase Manhattan Bank, N.A.
         Private Placement Servicing
         P. O. Box 1508
         Bowling Green Station
         New York, New York 10081
         Fax: (212) 623-6422 Private Placements

Name of Nominee in which Notes are to be issued: CUDD & CO

Taxpayer I.D. Number for First Penn-Pacific:  23-2044248



                                   Schedule A


<PAGE>   36





                     NAME AND ADDRESS                      PRINCIPAL AMOUNT
                       OF PURCHASER                        OF SERIES A NOTES
                                                           TO BE PURCHASED

LINCOLN LIFE & ANNUITY COMPANY OF NEW YORK                 $500,000
c/o Lincoln Investment Management, Inc.
200 East Berry Street
Renaissance Square
Fort Wayne, Indiana 46802
Attention: Investments/Private Placements
Fax:     (212) 455-5499 Private Placements

Payments

All payments on or in respect of the Notes to be by bank wire transfer of
Federal or other immediately available funds (identifying each payment as "Noble
Drilling (Paul Romano) Inc., Senior Secured Notes, Series A, PPN 65504# AA 8,
interest rate, maturity date, principal, premium or interest") to:

         Bankers Trust Company
         New York, New York
         ABA #021001033
         Private Placement Processing
         Account Number 99-911-145

         for the account of: Lincoln Life & Annuity Company of New York
         Custody Account Number: 98722

Notices

All notices and communications, including notices with respect to payments and
written confirmation of each such payment, to be addressed as first provided
above with duplicate notices with respect to payments to:

         Bankers Trust Company
         Attention: Private Placement Unit
         P. O. Box 998
         Bowling Green Station
         New York, New York 10274
         Fax: (615) 835-2493 Private Placements

Name of Nominee in which Notes are to be issued: None

Taxpayer I.D. Number: 16-1505436


                                   Schedule A


<PAGE>   37






                     NAME AND ADDRESS                      PRINCIPAL AMOUNT
                       OF PURCHASER                        OF SERIES A NOTES
                                                           TO BE PURCHASED

THE LINCOLN NATIONAL LIFE INSURANCE COMPANY                $10,000,000
c/o Lincoln Investment Management, Inc.
200 East Berry Street
Renaissance Square
Fort Wayne, Indiana 46802
Attention: Investments/Private Placements
Fax:     (212) 455-5499 Private Placements

Payments

All payments on or in respect of the Notes to be by bank wire transfer of
Federal or other immediately available funds (identifying each payment as "Noble
Drilling (Paul Romano) Inc., Senior Secured Notes, Series A, PPN 65504# AA 8,
interest rate, maturity date, principal, premium or interest") to:

         Chase Manhattan Bank
         New York, New York
         ABA #021000021
         CHASE NYC/CTR/BNF
         A/C #900-9-000200
         Further Credit: G07176 The Lincoln National Life Insurance Company 
                         (IACC)

Notices

All notices and communications, including notices with respect to payments and
written confirmation of each such payment, to be addressed as first provided
above with duplicate notices with respect to payments to:

         Chase Manhattan Bank, N.A.
         Private Placement Servicing
         P. O. Box 1508
         Bowling Green Station
         New York, New York 10081
         Fax: (212) 623-6422 Private Placements

Name of Nominee in which Notes are to be issued: None

Taxpayer I.D. Number: 35-0472300



                                   Schedule A


<PAGE>   38





                     NAME AND ADDRESS                      PRINCIPAL AMOUNT
                       OF PURCHASER                        OF SERIES A NOTES
                                                           TO BE PURCHASED

THE LINCOLN NATIONAL LIFE INSURANCE COMPANY                $5,000,000 (LFP)
c/o Lincoln Investment Management, Inc.                    $5,000,000 (ILG)
200 East Berry Street                                      $4,000,000 (IDP)
Renaissance Square
Fort Wayne, Indiana 46802
Attention: Investments/Private Placements
Fax:     (212) 455-5499 Private Placements

Payments

All payments on or in respect of the Notes to be by bank wire transfer of
Federal or other immediately available funds (identifying each payment as "Noble
Drilling (Paul Romano) Inc., Senior Secured Notes, Series A, PPN 65504# AA 8,
interest rate, maturity date, principal, premium or interest") to:

         Bankers Trust Company
         New York, New York
         ABA #021001033
         Private Placement Processing
         A/C #99-911-145

         for the account of: The Lincoln National Life Insurance Company (LFP)
         Custody Account Number 98185

         for the account of: The Lincoln National Life Insurance Company (ILG)
         Custody Account Number 98184

         for the account of: The Lincoln National Life Insurance Company (IDP)
         Custody Account Number 98131

Notices

All notices and communications, including notices with respect to payments and
written confirmation of each such payment, to be addressed as first provided
above with duplicate notices with respect to payments to:



                                   Schedule A


<PAGE>   39



         Bankers Trust Company
         Attn: Private Placement Unit
         P. O. Box 998
         Bowling Green Station
         New York, New York 10274
         Fax: (615) 835-2493
         Crystal Jones, Private Placements

Name of Nominee in which Notes are to be issued: None

Taxpayer I.D. Number: 35-0472300



                                   Schedule A


<PAGE>   40




                     NAME AND ADDRESS                      PRINCIPAL AMOUNT
                       OF PURCHASER                        OF SERIES A NOTES
                                                           TO BE PURCHASED

NATIONWIDE LIFE INSURANCE COMPANY                          $10,000,000
SEPARATE ACCOUNT NPPVA
One Nationwide Plaza (1-33-07)
Columbus, Ohio 43215-2220
Attention: Corporate Fixed-Income Securities

Payments

All payments on or in respect of the Notes to be by bank wire transfer of
Federal or other immediately available funds (identifying each payment as "Noble
Drilling (Paul Romano) Inc., Senior Secured Notes, Series A, PPN 65504# AA 8,
interest rate, maturity date, principal, premium or interest") to:

         The Bank of New York
         ABA #021-000-018
         BNF: IOC566
         F/A/O Nationwide Life Insurance Company Separate Account NPPVA
         Attention: P&I Department

Notices

All notices of payment on or in respect of the Notes and written confirmation of
each such payment to:

         Nationwide Life Insurance Company Separate Account NPPVA
         c/o The Bank of New York
         P. O. Box 19266
         Newark, New Jersey 07195
         Attention: P&I Department

With a copy to:

         Nationwide Life Insurance Company Separate Account NPPVA
         One Nationwide Plaza (1-32-05)
         Columbus, Ohio 43215-2220
         Attention: Investment Accounting

All notices and communications other than those in respect to payments to be
addressed as first provided above.

Name of Nominee in which Notes are to be issued: None

Taxpayer I.D. Number: 31-4156830


                                   Schedule A


<PAGE>   41





                     NAME AND ADDRESS                      PRINCIPAL AMOUNT
                       OF PURCHASER                        OF SERIES A NOTES
                                                           TO BE PURCHASED

PROVIDENT MUTUAL LIFE INSURANCE                            $3,000,000
   COMPANY
P. O. Box 1717
Valley Forge, Pennsylvania 19482-1717
Attention:  Securities Investment Department
Telefacsimile:  (610) 407-1322

Payments

All payments on or in respect of the Notes to be by bank wire transfer of
Federal or other immediately available funds (identifying each payment as "Noble
Drilling (Paul Romano) Inc., Senior Secured Notes, Series A, PPN 65504# AA 8,
interest rate, maturity date, principal, premium or interest") to:

         PNC Bank
         Broad and Chestnut Streets
         Philadelphia, Pennsylvania  19101
         ABA #031-000-053

         for credit to
         Provident Mutual Life Insurance Co.
         Account No.: 085-4084-2176

Notices

All notices and communications to be addressed as first provided above, except
notice with respect to payment and written confirmation of each such payment, to
be addressed Attention: Treasurer. In the event that notices/communications are
sent by courier (e.g., Federal Express) rather than by regular U.S. Postal
Service, the address should be changed to: 1205 Westlakes Drive, Berwyn,
Pennsylvania 19312-2405, Attention: Treasurer.

Name of Nominee in which Notes are to be issued: None

Taxpayer I.D. Number:  23-099-045-0



                                   Schedule A


<PAGE>   42






                     NAME AND ADDRESS                      PRINCIPAL AMOUNT
                       OF PURCHASER                        OF SERIES A NOTES
                                                           TO BE PURCHASED

SUNAMERICA LIFE INSURANCE COMPANY                          $10,000,000
700 Louisiana, Suite 3905
Houston, Texas 77002

Payments

All payments on or in respect of the Notes to be by bank wire transfer of
Federal or other immediately available funds (identifying each payment as "Noble
Drilling (Paul Romano) Inc., Senior Secured Notes, Series A, PPN 65504# AA 8,
interest rate, maturity date, principal, premium or interest") to:

         Bankers Trust Company
         ABA #021001033
         Account Number:  99-911-145
         For further credit to account number: 099530
         Reference:  Allied Capital Corporation
         PPN No.: 01903# A A O

Notices

         SunAmerica Corporate Finance
         700 Louisiana, Suite 3905
         Houston, Texas 77002
         Attention:  Investment Accounting, Debbie Adami
         Telephone: (713) 546-1116
         Fax:     (713) 222-1402

Name of Nominee in which Notes are to be issued: OKGBD & Co.

Taxpayer I.D. Number: 52-0502540



                                   Schedule A


<PAGE>   43





                     NAME AND ADDRESS                      PRINCIPAL AMOUNT
                       OF PURCHASER                        OF SERIES B NOTES
                                                           TO BE PURCHASED

BANNER RECEIVABLES CORPORATION                             $16,837,500
c/o The Bank of Tokyo-Mitsubishi, Ltd.
1252 Avenue of the Americas, 10th Floor
New York, NY 10020
Attention:  Aditya Reddy
Facsimile:  212-782-6448
Telephone:  212-782-6957

Payments

All payments on or in respect of the Notes to be by bank wire transfer of
Federal or other immediately available funds (identifying each payment as "Noble
Drilling (Paul Romano) Inc., Senior Secured Notes, Series B, interest rate,
maturity date, principal, premium or interest") to:

         Bank of Tokyo-Mitsubishi Trust Company
         1252 Avenue of the Americas, 10th Floor
         New York, NY 10020
         ABA # 026009687

         For credit to Banner Receivables Corporation
         Account No.: 210010495
         Attention:  Securitization Group/Asset Management

Notices

All notices and communications to be addressed as first provided above.

Name of Nominee in which Notes are to be issued: None

Taxpayer I.D. Number: 04-3185303



                                   Schedule A


<PAGE>   44






                     NAME AND ADDRESS                      PRINCIPAL AMOUNT
                       OF PURCHASER                        OF SERIES A NOTES
                                                           TO BE PURCHASED

PROVIDENTMUTUAL LIFE AND ANNUITY                           $2,000,000
   COMPANY OF AMERICA
P. O. Box 1717
Valley Forge, Pennsylvania 19482-1717
Attention:  Securities Investment Department
Telefacsimile:  (610) 407-1322

Payments

All payments on or in respect of the Notes to be by bank wire transfer of
Federal or other immediately available funds (identifying each payment as "Noble
Drilling (Paul Romano) Inc., Senior Secured Notes, Series A, PPN 65504# AA 8,
interest rate, maturity date, principal, premium or interest") to:

         PNC Bank
         Broad and Chestnut Streets
         Philadelphia, Pennsylvania  19101
         ABA #031-000-053

         for credit to
         Providentmutual Life and Annuity Company of America
         Account No.: 085-5075-4911

Notices

All notices and communications to be addressed as first provided above, except
notice with respect to payment and written confirmation of each such payment, to
be addressed Attention: Treasurer. In the event that notices/communications are
sent by courier (e.g., Federal Express) rather than by regular U.S. Postal
Service, the address should be changed to: 1205 Westlakes Drive, Berwyn,
Pennsylvania 19312-2405, Attention: Treasurer.

Name of Nominee in which Notes are to be issued: None

Taxpayer I.D. Number:  23-161-908-2




                                   Schedule A


<PAGE>   45



                                                                      SCHEDULE B


                                  DEFINED TERMS

         As used herein, the following terms have the respective meanings set
forth below or set forth in the Section hereof following such term:

         "AFFILIATE" shall have the meaning set forth in the Trust Indenture.

         "AGREEMENT" is defined in Section 9.3.

         "ASSET TRANSFER AGREEMENT" means the agreement, substantially in the
form of Exhibit 2 to this Agreement, to be dated on or before the Purchase Date,
between Noble US and the Company, pursuant to which Noble US assigns to the
Company, among other things, valid legal and beneficial title to the Drilling
Rig and its interests in and to the Shell Contract.

         "ASSIGNMENT OF DRILLING CONTRACT REVENUE" means the agreement
substantially in the form of Exhibit 7 to this Agreement.

         "BASIS POINT" means one-hundredth of one percent per annum.

         "BUSINESS DAY" shall have the meaning set forth in the Trust Indenture.

         "CAPITAL FUNDING AGREEMENT" means an agreement, substantially in the
form of Exhibit 3 to this Agreement that may be entered into subsequent to
Closing between Noble US and the Company, which agreement shall be assigned to
the Trustee.

         "CAPITAL LEASE" means, at any time, a lease with respect to which the
lessee is required concurrently to recognize the acquisition of an asset and the
incurrence of a liability in accordance with GAAP.

         "CLOSING" is defined in Section 3.

         "CODE" shall have the meaning set forth in the Trust Indenture.

         "COMPANY" means Noble Drilling (Paul Romano) Inc., a Delaware
corporation.

         "COMMITMENT TERMINATION DATE" is defined in Section 2.

         "CONFIDENTIAL INFORMATION" is defined in Section 12.

         "CREDIT DOCUMENTS" shall have the meaning set forth in the Trust
Indenture.




                               Schedule B - Page 1


<PAGE>   46



         "CREDIT SUPPORT PARTY" shall have the meaning set forth in the Trust
Indenture.

         "DEBT" shall have the meaning set forth in the Trust Indenture.

         "DEBT SERVICE RESERVE FUND" shall have the meaning set forth in the
Trust Indenture.

         "DRILLING ORDER" means the Marine Drilling Order of Noble US dated July
22, 1997 and accepted and approved by SDDI on August 14, 1997 as amended by that
certain letter dated May 20, 1997 from Noble Drilling Services Inc. to Shell
Offshore Inc.

         "DRILLING RIG" shall have the meaning set forth in the Trust Indenture.

         "DEFAULT RATE" shall have the meaning set out in the Trust Indenture.

         "ENVIRONMENTAL LAWS" shall have the meaning set out in the Trust
Indenture.

         "ERISA" shall have the meaning set forth in the Trust Indenture.

         "ERISA AFFILIATE" means any trade or business (whether or not
incorporated) that is treated as a single employer together with the Company
under section 414 of the Code.

         "EXCEPTED LIENS" shall have the meaning set out in the Trust Indenture.

         "EXCHANGE ACT" means the Securities Exchange Act of 1934, as amended
from time to time.

         "FIRST NAVAL MORTGAGE" means the mortgage of the Drilling Rig,
substantially in the form of Exhibit 6 to this Agreement, to be dated on or
before the Purchase Date, from the Company to the Trustee.

         "GAAP" shall have the meaning set forth in the Trust Indenture.

         "GOVERNMENTAL AUTHORITY" shall have the meaning set forth in the Trust
Indenture.

         "INDENTURE DEFAULT" shall have the meaning set out in the Trust
Indenture.

         "INDENTURE EVENT OF DEFAULT" shall have the meaning set out in the
Trust Indenture.

         "INSTITUTIONAL INVESTOR" means (a) any original purchaser of a Note,
(b) any holder of a Note holding more than 5% of the aggregate principal amount
of either Series of the Notes then outstanding, (c) any Credit Support Party and
(d) any bank, trust company, savings and loan association or other financial
institution, any pension plan, any investment company, any insurance company,
any broker or dealer, or any other similar financial institution or entity,
regardless of legal form.




                               Schedule B - Page 2


<PAGE>   47



         "LIEN" shall have the meaning set forth in the Trust Indenture.

         "MAJORITY HOLDERS" shall have the meaning set forth in the Trust
Indenture.

         "MATERIAL" means material in relation to the business, operations,
affairs, financial condition, assets, or properties of the Company or of Noble
US and its Subsidiaries taken as a whole (or in the case of Section 5.9, Noble
Corp. and its Subsidiaries taken as a whole).

         "MATERIAL ADVERSE EFFECT" means a material adverse effect on (a) the
business, operations, affairs, financial condition, assets or properties of the
Company or of Noble US and its Subsidiaries taken as a whole (or in the case of
Sections 5.3 or 5.8, Noble Corp. and its Subsidiaries taken as a whole), or (b)
the ability of the Company or of Noble US to perform its respective obligations
under this Agreement, the Notes or any other Credit Documents, or (c) the
validity or enforceability of this Agreement or the Notes or any other Credit
Documents.

         "MATURITY DATE" means the date which is five (5) years from the
Purchase Date.

         "MEMORANDUM" is defined in Section 5.3.

         "MULTIEMPLOYER PLAN" means any Plan that is a "multiemployer plan" (as
such term is defined in section 4001(a)(3) of ERISA).

         "NOBLE CORP." means Noble Drilling Corporation, a Delaware corporation.

         "NOBLE US" means Noble Drilling (U.S.) Inc., a Delaware corporation.

         "NOTES" is defined in Section 1.

         "OFFICER'S CERTIFICATE" means a certificate of a Senior Financial
Officer or of any other officer of the Company whose responsibilities extend to
the subject matter of such certificate.

         "OPERATING SERVICES AGREEMENT" means the agreement, substantially in
the form of Exhibit 4 to this Agreement, to be dated on or before the Purchase
Date, between Noble US and the Company.

         "OTHER AGREEMENTS" is defined in Section 2.

         "OTHER PURCHASERS" is defined in Section 2.

         "PBGC" means the Pension Benefit Guaranty Corporation referred to and
defined in ERISA or any successor thereto.

         "PERFORMANCE AGREEMENT" means the agreement, substantially in the form
of Exhibit 5 to this Agreement, to be dated on or before the Purchase Date.



                               Schedule B - Page 3


<PAGE>   48



         "PERSON" has the meaning set forth in the Trust Indenture.

         "PLANS" has the meaning set forth in the Trust Indenture.

         "PROPERTY" or "property" has the meaning set forth in the Trust
Indenture.

         "PURCHASE DATE" means the date on which the conditions to Closing under
Section 4 hereof have been satisfied or such other date thereafter agreed to
pursuant to Section 3 hereof.

         "QPAM EXEMPTION" means Prohibited Transaction Class Exemption 84-14
issued by the United States Department of Labor.

         "RESPONSIBLE OFFICER" means any Senior Financial Officer and any other
officer of the Company with responsibility for the administration of the
relevant portion of this agreement.

         "RIG APPRAISAL AND ENGINEERING REPORT" means Exhibit D to the
Memorandum.

         "ROYAL DUTCH SHELL" means, collectively, Royal Dutch Petroleum Company,
a company incorporated in The Netherlands, and The "Shell" Transport and Trading
Company, plc, a public limited company incorporated in England and Wales.

         "SDDI" means Shell Deepwater Development Inc., a Delaware corporation.

         "SDDI ACCEPTANCE CERTIFICATE" means a written certificate,
substantially in the form attached hereto as Exhibit 13, executed and delivered
by SDDI to the Trustee on or before the Purchase Date.

         "SDDI ACKNOWLEDGMENT AND CONSENT" means a written acknowledgment and
consent, substantially in the form attached hereto as Exhibit 14, executed and
delivered by SDDI to the Trustee on or before the Purchase Date, pursuant to
which SDDI agrees to make all payments due under the Shell Contract to the
Trustee so long as any Notes are outstanding.

         "SECURITIES ACT" means the Securities Act of 1933, as amended from time
to time.

         "SENIOR FINANCIAL OFFICER" means the chief financial officer, principal
accounting officer, treasurer or controller of the Company.

         "SERIES A NOTES" is defined in Section 1.

         "SERIES B NOTES" is defined in Section 1.

         "SHELL CONTRACT" means the Master Drilling Agreement, dated as of June
1, 1997, between SDDI and Noble US, together with the Drilling Order.




                               Schedule B - Page 4


<PAGE>   49



         "SUBSIDIARY" means, as to any Person, any corporation, association or
other business entity in which such Person or one or more of its Subsidiaries or
such Person and one or more of its Subsidiaries owns sufficient equity or voting
interests to enable it or them (as a group) ordinarily, in the absence of
contingencies, to elect a majority of the directors (or Persons performing
similar functions) of such entity, and any partnership or joint venture if more
than a 50% interest in the profits or capital thereof is owned by such Person or
one or more of its Subsidiaries or such Person and one or more of its
Subsidiaries (unless such partnership can and does ordinarily take major
business actions without the prior approval of such Person or one or more of its
Subsidiaries). Unless the context otherwise clearly requires, any reference to a
"Subsidiary" is a reference to a Subsidiary of Noble US.

         "TRUST ESTATE" shall have the meaning set out in the Trust Indenture.

         "TRUST INDENTURE" is defined in Section 4.3.

         "TRUSTEE" shall have the meaning set out in the Trust Indenture.

         "WORKING CAPITAL FUND" shall have the meaning set out in the Trust
Indenture.

         "YEAR 2000 PROBLEM" shall have the meaning set out in the Trust
Indenture.




                               Schedule B - Page 5



<PAGE>   1
                                                                     EXHIBIT 4.2












                        NOBLE DRILLING (PAUL ROMANO) INC.




                        -------------------------------

                                 TRUST INDENTURE
                             AND SECURITY AGREEMENT

                        -------------------------------


                        Dated as of ______________, 1998





<PAGE>   2




                                TABLE OF CONTENTS
<TABLE>
<CAPTION>
                                                                                                               Page
<S>               <C>                                                                                          <C>

                  ARTICLE 1.        DEFINED TERMS.................................................................3
                  1.1      Special Definitions....................................................................3

                  ARTICLE 2.        FORM, EXECUTION, ISSUE AND DELIVERY OF NOTES.................................13
                  2.1      Issue of Notes........................................................................13

                  2.2      Authentication of Notes; Denominations of Notes and Form..............................14
                  2.3      Registration of Notes.................................................................14
                  2.4      Exchange of Notes.....................................................................14
                  2.5      Transfer of Notes.....................................................................14
                  2.6      General Rules.........................................................................16
                  2.7      Valid Obligations.....................................................................16
                  2.8      Execution and Delivery................................................................17
                  2.9      Replacement of Notes..................................................................17

                  ARTICLE 3.        PAYMENTS AND DISTRIBUTION THEREOF............................................17
                  3.1      Payment by Issuer.....................................................................17
                  3.2      Delivery Expenses.....................................................................18
                  3.3      Issue Taxes...........................................................................18
                  3.4      Required Payments of Notes without Premium............................................18
                  3.5      Optional Prepayment of the Notes with Make-Whole Amount...............................19
                  3.6      Required Prepayments of Notes.........................................................19
                  3.7      Surrender of Notes on Prepayment......................................................20
                  3.8      Provision for Applicable Make-Whole Amount, Yield Protection Amount
                           and Breakage Amount...................................................................20
                  Breakage Amount................................................................................23

                  ARTICLE 4.        RECEIPT, DISTRIBUTION AND APPLICATION OF TRUST
                                    ESTATE.......................................................................23
                  4.1      Application of Shell Contract Revenues When No Indenture Event of Default
                           is Continuing.........................................................................23
                  4.2      (a)      Payments in Case of an Early Termination.....................................24
                  (b)      Payments in Case of an Event of Loss..................................................25
                  (c)      Payments in Case of a Partial Event of Loss...........................................25
                  4.3      Payments During Continuance of an Indenture Event of Default..........................27
                  4.4      Amounts Held by Trustee...............................................................28
                  4.5      Allocation of Payments................................................................28
                  4.6      Method of Payment to Holders..........................................................28
                  4.7      Method of Payment to Issuer...........................................................29
                  4.8      Payments for which No Application is Otherwise Provided...............................29
</TABLE>


                                                      -i-


<PAGE>   3


<TABLE>
<CAPTION>

<S>               <C>                                                                                          <C>
                  ARTICLE 5.        EVIDENCE OF ACTS OF NOTE HOLDERS.............................................29
                  5.1      Execution by Note Holders or Agents...................................................29
                  5.2      Future Holders Bound..................................................................29

                  ARTICLE 6.        INDENTURE DEFAULTS - REMEDIES................................................29
                  6.1      Indenture Events of Default...........................................................29
                  6.2      Acceleration of Notes.................................................................32
                  6.3      Annulment of Acceleration of Notes....................................................33
                  6.4      Default Remedies......................................................................33
                  6.5      Other Enforcement Rights..............................................................36
                  6.6      Effect of Sale, etc...................................................................37
                  6.7      Restoration of Rights and Remedies....................................................38
                  6.8      Application of Sale Proceeds and Deficiency...........................................38
                  6.9      Cumulative Remedies...................................................................38
                  6.10     Limitations on Suits..................................................................39
                  6.11     Suits for Principal and Interest......................................................39
                  6.12     Waiver by the Issuer..................................................................39

                  ARTICLE 7.        AFFIRMATIVE COVENANTS........................................................40
                  7.1      Financial Statements..................................................................41
                  7.2      Litigation............................................................................43
                  7.3      Maintenance, Etc......................................................................43
                  7.4      Environmental Matters.................................................................46
                  7.5      Further Assurances....................................................................46
                  7.6      Performance of Obligations............................................................47
                  7.7      ERISA Information and Compliance......................................................47
                  7.8      Debt Service Reserve Fund.............................................................47
                  7.9      Maintenance of Agency.................................................................48
                  7.10     Additional Assurances.................................................................48
                  7.11     Year 2000 Compliance..................................................................48
                  7.12     Change in Location of Collateral or Issuer............................................49
                  7.13     Change in Issuer's Name...............................................................49
                  7.14     Corporate Independence................................................................49
                  7.15     Working Capital Fund..................................................................50

                  ARTICLE 8.        NEGATIVE COVENANTS...........................................................50
                  8.1      Debt..................................................................................50
                  8.2      Liens.................................................................................51
                  8.3      Investments, Loans and Advances.......................................................51
                  8.4      Dividends, Distributions and Redemptions..............................................51
                  8.5      Sales and Leasebacks..................................................................51
                  8.6      Nature of Business....................................................................51
                  8.7      Limitation on Leases..................................................................51
                  8.8      Mergers, Etc..........................................................................51
                  8.9      Proceeds of Notes.....................................................................52
                  8.10     ERISA Compliance......................................................................52
</TABLE>


                                      -ii-


<PAGE>   4

<TABLE>
<CAPTION>

<S>               <C>                                                                                          <C>
                  8.11     Sale or Discount of Receivables.......................................................53
                  8.12     Sale of Drilling Rig..................................................................53
                  8.13     Environmental Matters.................................................................53
                  8.14     Transactions with Affiliates..........................................................53
                  8.15     Subsidiaries..........................................................................53
                  8.16     Location of Issuer....................................................................54
                  8.17     Acquisition of Notes..................................................................54
                  8.18     Non-Petition Covenant.................................................................54

                  ARTICLE 9.        THE TRUSTEES.................................................................54
                  9.1      Certain Duties and Responsibilities of Trustees.......................................54
                  9.2      Trustees' Compensation and Indemnification............................................55
                  9.3      Certain Rights of Trustees............................................................56
                  9.4      Showings Deemed Necessary by a Trustee................................................57
                  9.5      Status of Monies Received.............................................................58
                  9.6      Resignation of Trustees...............................................................58
                  9.7      Removal of Trustees...................................................................58
                  9.8      Successor Trustee.....................................................................58
                  9.9      Appointment of Successor Trustees.....................................................58
                  9.10     Merger or Consolidation of Trustee....................................................59
                  9.11     Acceptance of Appointment by Successor Trustee........................................59
                  9.12     Conveyance upon Request of Successor Trustee..........................................59
                  9.13     Co-Trustees and Additional Trustees...................................................59
                  9.14     Trustee's Representations and Warranties..............................................60
                  9.15     Non-Petition Covenant.................................................................61

                  ARTICLE 10.       SUPPLEMENTAL INDENTURES, WAIVERS.............................................61
                  10.1     Supplemental Indentures Without Note Holders' Consent.................................61
                  10.2     Waivers and Consents by Note Holders; Supplemental Indentures with
                           Consent...............................................................................62
                  10.3     Notice of Supplemental Indenture......................................................63
                  10.4     Solicitation of Note Holders..........................................................63
                  10.5     Opinion of Counsel Conclusive as to Supplemental Indentures...........................63
                  10.6     Effect of Supplemental Indentures.....................................................63
                  10.7     New Notes.............................................................................64

                  ARTICLE 11.       UNCLAIMED MONIES.............................................................64
                  11.1     Satisfaction and Discharge of Agreement...............................................64
                  11.2     Return of Unclaimed Monies............................................................64

                  ARTICLE 12.       MISCELLANEOUS................................................................65
                  12.1     Successors and Assigns................................................................65
                  12.2     Partial Invalidity....................................................................65
                  12.3     Communications........................................................................65
                  12.4     GOVERNING LAW; SUBMISSION TO JURISDICTION.............................................66
                  12.5     Limitation on Interest................................................................67
</TABLE>


                                      -iii-


<PAGE>   5


<TABLE>
<CAPTION>

<S>               <C>                                                                                          <C>
                  12.6     Counterparts..........................................................................69
                  12.7     Headings, etc.; Gender................................................................69
                  12.8     Amendments............................................................................69
                  12.9     Benefits of Agreement Restricted to Parties and Note Holders..........................69
                  12.10    Waiver of Notice......................................................................69
                  12.11    Intentionally Omitted.................................................................69
                  12.12    Additional Financing Statement Filings................................................69
                  12.13    Directly or Indirectly................................................................70
                  12.14    Exhibits, Annexes and Sections........................................................70
                  12.15    Officers' Certificate and Opinions of Counsel; Statements to be Contained
                           Therein...............................................................................70
                  12.16    Payment of Expenses, Indemnities, etc.................................................71
                  12.17    NO ORAL AGREEMENTS....................................................................74
                  12.18    EXCULPATION PROVISIONS................................................................74
                  12.19    Trustees Not Engaging in a Trade or Business..........................................74
</TABLE>


<TABLE>

<S>                   <C>      <C>
Annex A-1             --        Form of Series A Note

Annex A-2             --        Form of Series B Note

Annex B               --        Series A Note Payment Schedule

Annex C               --        Form of Intercompany Subordinated Note

Annex D               --        Surveys and Inspections

Schedule 7.3          --        Insurance

Schedule 9.2          --        Trustee Fees

</TABLE>

                                      -iv-


<PAGE>   6



                     TRUST INDENTURE AND SECURITY AGREEMENT


         TRUST INDENTURE AND SECURITY AGREEMENT dated as of _____________, 1998,
between NOBLE DRILLING (PAUL ROMANO) INC., a Delaware corporation (the
"Issuer"), and CHASE BANK OF TEXAS, NATIONAL ASSOCIATION, a national banking
association (the "Trustee"; the Trustee and each other Person accepting trusts
created hereby being individually referred to as a "Trustee" and collectively as
the "Trustees").

                                    RECITALS:

         WHEREAS, the defined terms used in this Indenture shall have the
respective meanings set forth in Section 1.1 unless elsewhere defined or the
context shall otherwise require;

         WHEREAS, the Issuer is authorized by law, and deems it necessary to
borrow money for its proper legal purposes and to mortgage, assign and pledge
its Property to secure the payment thereof and to that end, in the exercise of
said authority, has duly authorized the execution and delivery of this Indenture
providing for the issue of secured promissory notes of the Issuer hereunder;

         WHEREAS, the Issuer has duly authorized the issuance of (i) its
drilling vessel secured notes limited in aggregate original principal amount to
Ninety-Five Million, Four Hundred Twelve Thousand, Five Hundred Dollars
($95,412,500) to be known as its Series A Senior Secured Notes, and (ii) its
drilling vessel secured notes limited in aggregate original principal amount to
Sixteen Million, Eight Hundred Thirty-Seven Thousand, Five Hundred Dollars
($16,837,500), to be known as its Series B Senior Secured Notes on the terms
herein provided;

         WHEREAS, the Notes and the Trustee's Certificate of Authentication
thereon are to be substantially in the forms set forth in Annexes A-1 and A-2;
and

         WHEREAS, all acts and proceedings required by law and by the
Certificate of Incorporation and Bylaws of the Issuer necessary to make the
Notes, when executed by the Issuer and authenticated and delivered by the
Trustee, the legal, valid and binding obligations of the Issuer, and all acts
and proceedings required by law and by the Certificate of Incorporation and
Bylaws of the Issuer necessary to constitute this Indenture a legal, valid and
binding agreement for the uses and purposes herein set forth, in accordance with
its terms, have been done and taken; and the Issuer has duly authorized,
executed and delivered this Indenture;

                                GRANTING CLAUSE:

         NOW, THEREFORE, THIS INDENTURE WITNESSETH, that to secure the prompt
and complete payment of the principal of, and interest and any applicable
Make-Whole Amount on, all of the Notes issued and delivered and Outstanding, the
payment of all other sums owing hereunder and under all other Credit Documents
and the performance of the covenants contained herein and in all other Credit
Documents, and in consideration of the premises and of the covenants contained
herein, the purchase of the Notes by the Purchasers, and the sum of One Dollar
($1.00) paid by the Trustee to the Issuer at or before the delivery hereof, the
receipt and sufficiency whereof are hereby



<PAGE>   7



acknowledged, the Issuer has hereby granted, bargained, sold, conveyed,
assigned, transferred, mortgaged, affected, pledged, set over, confirmed,
granted a continuing security interest in, and hypothecated and does hereby
grant, bargain, sell, convey, assign, transfer, mortgage, affect, pledge, set
over, confirm, grant a continuing security interest to the Trustee and to any
co-trustee or separate trustee hereafter acting pursuant to this Indenture, and
to their respective successors and assigns in trust forever, all of its right,
title and interest in, to and under the following described Properties (all of
such Properties, including without limitation all properties hereafter
specifically subjected to the lien of this Indenture by any indenture supplement
hereto, being hereinafter collectively referred to as the "Trust Estate"):

                  (a) All equipment, inventory, fixtures and other goods in all
         forms, wherever located and whether now or hereafter existing, which
         are owned by the Issuer or in which the Issuer otherwise has any rights
         and all parts thereof, all accessions thereto, all replacements or
         substitutions therefor, all accounts now or hereafter arising in
         connection therewith, and all chattel paper, documents and General
         Intangibles covering or relating thereto (any and all such equipment,
         inventory, fixtures, other goods, parts, accessions, replacements,
         substitutions, accounts, chattel paper, documents and General
         Intangibles being herein collectively called the "Pledged Equipment");

                  (b) All accounts, general intangibles (excluding the Shell
         Contract), chattel paper and documents, now owned or hereafter
         acquired;

                  (c) The Operating Services Agreement, the Asset Transfer
         Agreement and the Capital Funding Agreement (when and if executed and
         delivered);

                  (d) All Properties subjected to the Lien of this Indenture by
         each supplemental indenture entered into and delivered pursuant to
         Article 10;

                  (e) All insurance proceeds, condemnation proceeds and the
         accounts, issues, profits, products, revenues and other income of and
         from the Shell Contract and the other Properties subjected or required
         to be subjected to the Lien of this Indenture and all the estate,
         right, title and interest of every nature whatsoever of the Issuer in
         and to the same and every part thereof;

                  (f) The Collection Account, the Debt Service Reserve Fund, the
         Working Capital Account and all other monies now or hereafter paid or
         deposited or required to be paid or deposited to or with the Trustee
         pursuant to Section 4.1 or 4.3 hereof or any other term hereof or any
         term of the other Credit Documents and held or required to be held by
         any Trustee hereunder;

                  (g) Any and all other Properties and any and all other rights,
         interests and privileges granted to any Trustee in accordance with the
         provisions hereof and pursuant to or in connection with the provisions
         of the other Credit Documents, including but not limited to the First
         Naval Mortgage; and

                  (h) All proceeds of the foregoing.


                                       -2-


<PAGE>   8



                  It is expressly contemplated that additional property may from
         time to time be pledged, assigned or granted to the Trustee as
         additional security for the Outstanding Notes, and the term "Trust
         Estate" as used herein shall be deemed for all purposes hereof to
         include all such additional property, together with all other property
         of the types described above related thereto, and all proceeds and
         replacements of the same.

         TO HAVE AND TO HOLD, all and singular, the Trust Estate for the uses
and purposes and subject to the terms and provisions set forth in this Indenture
unto the Trustees and their respective successors in trust, and to their
respective assigns forever.

         IN TRUST NEVERTHELESS, under and subject to the terms and conditions
herein set forth and for the equal and proportionate, unless otherwise stated
herein, benefit and security of the holders from time to time of the Outstanding
Notes and for the enforcement of the prompt and complete payment when due of all
sums due in connection with the Outstanding Notes, this Indenture and each of
the other Credit Documents and for the performance and observance by the Issuer
of the covenants, obligations and conditions to be performed and observed by the
Issuer and all other parties, other than the Trustees and the holders of
Outstanding Notes, to this Indenture and each of the other Credit Documents;

         PROVIDED, HOWEVER, that these presents are upon the condition that if
the Issuer, its successors or assigns, shall satisfy the conditions set forth in
Section 11.1 for a release of the Trust Estate in full, then this Indenture, and
the estates and rights assigned in the other Credit Documents, shall cease,
determine and be void; otherwise they shall remain and be in full force and
effect;

         IT IS HEREBY FURTHER COVENANTED AND AGREED that all of the Notes are to
be issued, authenticated and delivered and that the Trust Estate is to be held
and applied by the Trustees, subject to the further covenants, agreements,
conditions, uses and trust hereafter set forth. The Issuer for itself and its
successors and permitted assigns does hereby covenant and agree with the
Trustees and their respective successors in trust for the benefit of all present
and future holders of the Outstanding Notes, or any of them, as follows:

ARTICLE 1.        DEFINED TERMS.

         1.1 Special Definitions. For purposes of this Indenture, the following
terms shall have the respective meanings (i) set forth below, (ii) set forth in
the Section or other part of this Indenture following such term or (iii)
provided for in the section or other part of such other Credit Document as may
be referred to immediately following such term (such definitions to be equally
applicable to both the singular and plural forms of the terms defined):

                  Affiliate -- at any time, and with respect to any Person, any
         other Person that at such time directly or indirectly through one or
         more intermediaries Controls, or is Controlled by, or is under common
         Control with, such first Person. As used in this definition, "CONTROL"
         means the possession, directly or indirectly, of the power to direct or
         cause the direction of the management and policies of a Person, whether
         through the ownership of voting securities, by contract or otherwise.
         Unless the context otherwise clearly requires, any reference to an
         "Affiliate" is a reference to an Affiliate of the Issuer.

                                       -3-


<PAGE>   9



                  Asset Purchase Agreement -- the Asset Purchase Agreement with
         respect to the Series B Notes, dated as of the date hereof, among
         Banner Receivables Corporation, BTM Capital Corporation, BTM, Ltd., as
         agent, and the banks party thereto, as from time to time amended,
         supplemented or modified.

                  Asset Transfer Agreement -- the Asset Transfer Agreement of
         even date herewith from the Parent to the Issuer covering the Drilling
         Rig and the Shell Contract.

                  Assignment of Drilling Contract Revenue -- has the meaning set
         out in Schedule B to the Note Purchase Agreements.

                  Banner Credit Agreement -- the Credit Agreement dated as of
         April 23, 1993, among Banner Receivables Corporation, BTM, Ltd., and
         BTMTC, as administrator, as such agreement has been and may be from
         time to time further amended, supplemented or modified.

                  Breakage Amount -- the amount determined pursuant to Section
         3.8(c).

                  Breakage Party -- has the meaning set out in Section 3.8(c).

                  BTM, Ltd. -- The Bank of Tokyo - Mitsubishi, Ltd., New York 
         Branch.

                  BTMTC -- Bank of Tokyo - Mitsubishi Trust Company.

                  Business Day -- a day other than a Saturday, a Sunday or a day
         on which banks are required or allowed by law (other than a general
         banking moratorium or holiday for a period exceeding four (4)
         consecutive days) to be closed in one or both of the State of Texas and
         New York.

                  Capital Funding Agreement -- has the meaning set out in
         Schedule B to the Note Purchase Agreements.

                  Closing Date -- the date of the initial issuance of the Notes.

                  Code -- the Internal Revenue Code of 1986, as amended from
         time to time.

                  Collateral -- the Trust Estate, and any and all other
         collateral held by any one or more of the Trustees to secure the Notes
         or any other obligations created pursuant to the Credit Documents,
         including without limitation the Credit Documents and all collateral
         covered thereby.

                  Collection Account -- has the meaning set out in Section 4.1.

                  Consolidated -- the consolidation of any Person with its
         properly consolidated subsidiaries, in accordance with GAAP.


                                       -4-


<PAGE>   10



                  Contested in Good Faith -- actively contested in good faith by
         appropriate actions or proceedings provided that (i) adequate book
         reserves have been established with respect thereto as required by
         GAAP, (ii) the applicable Person's title to, and its right to use, any
         of its material Property is not materially adversely affected thereby
         and (iii) the action to be taken will not result in any risk of
         imposition of civil or criminal penalties on the Trustee or the holders
         of the Notes or substantial danger of sale, forfeiture or loss of the
         Drilling Rig.

                  CP Conduit -- Gotham Funding Corporation, Banner Receivables
         Corporation or any other commercial paper conduit administered by BTMTC
         which is an owner and holder of a Series B Note.

                  Credit Documents -- this Indenture, the Note Purchase
         Agreements, the Notes, the Performance Agreement, the Assignment of
         Drilling Contract Revenue, the Operating Services Agreement, the Asset
         Transfer Agreement, the Capital Funding Agreement, if any, the First
         Naval Mortgage, the SDDI Acknowledgment and Consent, and any and all
         other agreements or instruments now or hereafter executed and delivered
         by the Company or the Parent in connection with or a security for the
         payment and performance of the Notes.

                  Credit Support Party -- BTM, Ltd., BTMTC, BTM Capital
         Corporation and any other financial institutions providing funding,
         liquidity, credit or asset purchase support with respect to sourcing
         the funds for the Series B Notes.

                  Debt -- for any Person the sum of the following (without
         duplication): (i) all obligations of such Person for borrowed money or
         evidenced by bonds, debentures, notes or other similar instruments
         (including principal, interest, fees and charges); (ii) all obligations
         of such Person (whether contingent or otherwise) in respect of bankers'
         acceptances, letters of credit, surety or other bonds and similar
         instruments; (iii) all obligations of such Person to pay the deferred
         purchase price of Property or services (other than for borrowed money);
         (iv) all obligations under leases which shall have been, or should have
         been, in accordance with GAAP, recorded as capital leases in respect of
         which such Person is liable (whether contingent or otherwise); (v) all
         obligations under leases which require such Person or its Affiliate to
         make payments over the term of such lease, including payments at
         termination, which are substantially equal to at least eighty percent
         (80%) of the purchase price of the Property subject to such lease plus
         interest at an imputed rate of interest; (vi) all Debt (as described in
         the other clauses of this definition) and other obligations of others
         secured by a Lien on any asset of such Person, whether or not such Debt
         is assumed by such Person; (vii) all Debt (as described in the other
         clauses of this definition) and other obligations of others guaranteed
         by such Person or in which such Person otherwise assures a creditor
         against loss of the debtor or obligations of others; (viii) all
         obligations or undertakings of such Person to maintain or cause to be
         maintained the financial position or covenants of others or to purchase
         the Debt or Property of others; (ix) obligations to deliver goods or
         services in consideration of advance payments; (x) obligations to pay
         for goods or services whether or not such goods or services are
         actually received or utilized by such Person; (xi) any capital stock of
         such Person in which such Person has a mandatory obligation to redeem
         such stock; and (xii) all obligations of such Person under Hedging
         Agreements.


                                       -5-


<PAGE>   11



                  Debt Service Reserve Fund -- has the meaning set out in
         Section 7.8.

                  Default Rate -- 2% per annum above the prematurity interest
         rate set forth in the Series B Notes; except to the extent a "Default
         Rate" is called for in the Series A Notes when such rate shall be 2%
         per annum above the prematurity interest rate set forth in the Series A
         Notes.

                  Definitive Notes -- Series A Notes in the form of Exhibit A-1
         attached hereto and Series B Notes in the form of Exhibit A-2 attached
         hereto.

                  Drilling Order -- has the meaning attributed thereto in
         Schedule B to the Note Purchase Agreements.

                  Drilling Rig -- the drilling vessel and all equipment
         appurtenant thereto known as the "Noble Paul Romano" being the vessel
         and all equipment and other properties set out and described in the
         First Naval Mortgage.

                  Environmental Laws -- any and all Governmental Requirements
         pertaining to health, safety or the environment or the regulation of
         hazardous substances or pollutants in effect in any and all
         jurisdictions in which the Issuer is conducting or at any time has
         conducted business, or where any Property of the Issuer is located,
         including without limitation, the Oil Pollution Act of 1990 ("OPA"),
         the Clean Air Act, as amended, the Comprehensive Environ mental,
         Response, Compensation, and Liability Act of 1980 ("CERCLA"), as
         amended, the Federal Water Pollution Control Act, as amended, the
         Occupational Safety and Health Act of 1970, as amended, the Resource
         Conservation and Recovery Act of 1976 ("RCRA"), as amended, the Safe
         Drinking Water Act, as amended, the Toxic Substances Control Act, as
         amended, the Superfund Amendments and Reauthorization Act of 1986, as
         amended, the Hazardous Materials Transportation Act, as amended, and
         any other international, federal, local or state environmental
         conservation or protection laws. The terms "oil" and "discharge" shall
         have the meanings specified in OPA, the terms "hazardous substance" and
         "release" (or "threatened release") have the meanings specified in
         CERCLA, except that "hazardous substance" shall also include petroleum
         and any fraction thereof, and the terms "solid waste" and "disposal"
         (or "disposed") have the meanings specified in RCRA; provided, however,
         that (i) in the event either OPA, CERCLA or RCRA is amended so as to
         broaden the meaning of any term defined thereby, such broader meaning
         shall apply subsequent to the effective date of such amendment and (ii)
         to the extent the laws of the state in which any Property of the Issuer
         is located establish a meaning for "oil," "discharge," "hazardous
         substance," "release," "solid waste" or "disposal" which is broader
         than that specified in either OPA, CERCLA or RCRA, such broader meaning
         shall apply.

                  ERISA -- the Employee Retirement Income Security Act of 1974,
         as amended from time to time.

                  ERISA Affiliate -- has the meaning set out in Schedule B to
         the Note Purchase Agreements.


                                       -6-


<PAGE>   12



                  ERISA Event -- (i) a "reportable event" described in Section
         4043 (c)(5), (c)(6), (c)(11) or (c)(13) of ERISA and the regulations
         issued thereunder, (ii) the filing of a notice of intent to terminate a
         Plan or the treatment of a Plan amendment as a termination under
         section 4041 of ERISA, (iii) the institution of proceedings by the
         Pension Benefit Guaranty Corporation ("PBGC") under Section 4042 of
         ERISA for the termination of, or the appointment of a trustee to
         administer, any Plan or (iv) the partial or complete withdrawal of
         Issuer or any ERISA Affiliate from a Multiemployer Plan.

                  Event of Loss -- has the meaning set out in the First Naval
         Mortgage.

                  Excepted Liens -- (i) Liens for taxes, assessments or other
         governmental charges or levies not yet due or which are being Contested
         In Good Faith; (ii) Liens in connection with workmen's compensation,
         unemployment insurance or other social security, old age pension or
         public liability obligations not yet due or which are being Contested
         In Good Faith; (iii) operators', vendors', carriers', warehousemen's,
         repairmen's, mechanics', workmen's, materialmen's, construction,
         shipyard liens (during repair or upgrade periods) or other like Liens
         arising by operation of law in the ordinary course of business or
         statutory landlord's liens, each of which is in respect of obligations
         that have not been outstanding more than 60 days (so long as no action
         has been taken to file or enforce such Liens within said 60 day period)
         or which are being Contested In Good Faith; (iv) deposits of cash or
         securities to secure the performance of bids, trade contracts, leases,
         statutory obligations and other obligations of a like nature incurred
         in the ordinary course of business; and (v) Liens permitted by the
         Credit Documents.

                  Exchange Act -- has the meaning set forth in Schedule B to the
         Note Purchase Agreements.

                  First Naval Mortgage -- has the meaning set forth in Schedule
         B to the Note Purchase Agreements.

                  GAAP -- those generally accepted accounting principles and
         practices which are recognized as such by the Financial Accounting
         Standards Board (or any generally recognized successor) as in effect
         from time to time.

                  General Intangibles -- all general intangibles related to any
         property that is part of the Trust Estate, including, without
         limitation, all (i) letters of credit, bonds, guaranties, purchase or
         sales agreements and other contractual rights other than the Shell
         Contract, rights to performance, and claims for damages, refunds
         (including tax refunds) or other monies due or to become due; (ii)
         orders, franchises, permits, certificates, licenses, consents,
         exemptions, variances, authorizations or other approvals by any
         governmental agency or court; (iii) consulting, engineering and
         technological information and specifications, design data, patent
         rights, trade secrets, literary rights, copyrights, trademarks, labels,
         trade names and other intellectual property; (iv) business records,
         computer tapes and computer software; (v) goodwill; and (vi) all other
         intangible personal property, whether similar or dissimilar to the
         other property that is part of the Trust Estate other than the Shell
         Contract.


                                       -7-


<PAGE>   13



                  Governmental Authority -- the country, the state, county, city
         and political subdivisions in which any Person or such Person's
         Property is located or which exercises jurisdiction over any such
         Person or such Person's Property, and any court, agency, department,
         commission, board, body, bureau or instrumentality of any of them
         including monetary authorities which exercises jurisdiction over any
         such Person or such Person's Property. Unless otherwise specified, all
         references to Governmental Authority herein shall mean a Governmental
         Authority having jurisdiction over, where applicable, the Issuer, the
         Parent or any of their Property or the Trustees or any Note Holder.

                  Governmental Requirements -- any law, statute, code,
         ordinance, order, determination, rule, regulation, publication,
         judgment, decree, injunction, franchise, permit, registration, consent,
         approval, certificate, license, authorization or other directive or
         requirement (whether or not having the force of law), including,
         without limitation, Environmental Laws, energy regulations and
         occupational, safety and health standards or controls, of any
         Governmental Authority.

                  Hedging Agreements -- any commodity, interest rate or currency
         swap, cap, floor, collar, forward agreement or other exchange or
         protection agreements or any option with respect to any such
         transaction.

                  Indemnified Parties -- has the meaning set out in Section
         12.16(b).

                  Indemnity Matters -- any and all actions, suits, proceedings
         (including any investigations, litigation or inquiries), orders,
         claims, demands and causes of action made or threatened against a
         Person and, in connection therewith, all settlements, judgments,
         losses, liabilities, obligations, damages, penalties, fines (including,
         without limitation, consequential damages) or reasonable costs and
         expenses of any kind or nature whatsoever incurred by such Person
         whether caused by the sole or concurrent negligence (but not gross
         negligence or willful misconduct) of such Person seeking
         indemnification.

                  Indenture -- this Trust Indenture and Security Agreement as
         originally executed or as it may from time to time be supplemented or
         amended in accordance with the provisions hereof.

                  Indenture Default -- an event or condition the occurrence of
         which would, with the lapse of time or the giving of notice or both,
         become an Indenture Event of Default.

                  Indenture Event of Default -- has the meaning set out in
         Section 6.1.

                  Independent Director -- has the meaning set out in the
         Certificate of Incorporation of the Issuer, as amended, as it existed
         on September 22, 1998.

                  Institutional Investor -- has the meaning set out in Schedule
         B to the Note Purchase Agreements.

                  Issuer -- has the meaning set out in the first paragraph of
         this Indenture.

                                       -8-


<PAGE>   14



                  Investment Grade -- a rating equal to or higher than "BBB-" by
         Standard & Poor's Rating Services, a division of The McGraw Hill
         Companies, Inc. or any successor thereto or equal to or higher than
         "Baa3" by Moody's Investors Service, Inc. or any successor thereto or a
         comparable rating by another nationally recognized statistical rating
         organization, which rating and organization are approved by the
         Majority Holders.

                  Lien -- any interest in Property securing an obligation owed
         to, or a claim by, a Person other than the owner of the Property,
         whether such interest is based on the common law, statute or contract,
         and including but not limited to the security interest or lien arising
         from a mortgage, encumbrance, pledge, conditional sale or other title
         retention agreement, trust receipt or a lease, consignment or bailment
         for security purposes. The term "Lien" shall include reservations,
         exceptions, encroachments, easements, rights-of-way, covenants,
         conditions, restrictions, leases and other title exceptions and
         encumbrances (including, with respect to stock, stockholder agreements,
         voting trust agreements, buy back agreements and all similar
         agreements) affecting the Property. For the purposes of this Indenture,
         a Person shall be deemed to be the owner of any Property which it has
         acquired or holds subject to a conditional sale agreement, financing
         lease or other arrangement pursuant to which title to the Property has
         been retained by or vested in some other Person for security purposes,
         and such retention or vesting shall constitute a Lien.

                  Liquidity Agreement -- the Liquidity Agreement, dated as of
         _______, 1998, among Banner Receivables Corporation, BTM, Ltd., as
         agent, the banks parties thereto and BTMTC as administrator, as from
         time to time amended, supplemented or modified.

                  Liquidity Documents -- the Banner Credit Agreement, the
         Liquidity Agreement and the Asset Purchase Agreement.

                  Loss Payment Date -- the date that the Company shall receive
         the proceeds of any insurance payment or settlement or any condemnation
         award or other payment in relation to an Event of Loss.

                  MPPAA -- Multiemployer Pension Plan Amendments Act of 1980, as
         amended.

                  Majority Holders -- at any time, holders of more than
         fifty-one percent (51%) in aggregate principal amount of all Notes then
         Outstanding (exclusive of any Notes held by the Issuer or any Affiliate
         of the Issuer).

                  Make-Whole Amount -- has the meaning set out in Section 3.8.

                  Material -- has the meaning set out in Schedule B to the Note
         Purchase Agreements.

                  Material Adverse Effect -- has the meaning set out in Schedule
         B to the Note Purchase Agreements.

                  Maturity Date -- has the meaning set out in Schedule B to the
         Note Purchase Agreements.

                                       -9-


<PAGE>   15



                  Multiemployer Plan -- has the meaning set out in Schedule B to
         the Note Purchase Agreements.

                  Noble Corp. -- Noble Drilling Corporation, a Delaware 
         corporation.

                  Note Holder -- the owner and holder of a Note registered with
         the Issuer as provided in Section 2.3.

                  Note Purchase Agreements -- the separate Note Purchase
         Agreements dated as of September 24, 1998, between the Issuer and each
         of the Purchasers in respect of the Notes.

                  Notes -- any or all of the Series A Notes and Series B Notes.

                  Operating Services Agreement -- has the meaning set forth in
         Schedule B to the Note Purchase Agreements.

                  Opinion of Counsel -- an opinion of outside counsel (which may
         from time to time serve as counsel for the Issuer, for the Trustee or
         for a Note Holder) reasonably acceptable to the Trustee, which opinion
         is in scope, form and substance reasonably satisfactory to the Trustee
         and the Trustee's counsel.

                  outer Continental Shelf -- shall have the meaning assigned to
         such term in 43 U.S.C. Section 1331.

                  Outstanding -- when used with reference to Notes shall mean,
         as of any particular time, all Notes authenticated and delivered by the
         Trustee under this Indenture, except:

                           (a) Notes theretofore canceled by the Trustee or
                  delivered to the Trustee for cancellation;

                           (b) Notes for the payment or prepayment of which
                  moneys in the necessary amount shall have been deposited in
                  trust with the Trustee; provided that if such Notes are to be
                  prepaid prior to the maturity thereof, notice of such
                  prepayment shall have been given as provided in Section 3.5 of
                  this Indenture, or provision satisfactory to the Trustee shall
                  have been made for giving such notice; and

                           (c) Notes in lieu of or in substitution for which
                  other Notes shall have been delivered pursuant to the terms of
                  Section 2.4, 2.5 or 2.9 of this Indenture.

                  Parent -- Noble Drilling (U.S.) Inc., a Delaware corporation.

                  Payment Date -- the twentieth (20th) day of each month of each
         year beginning in the calendar month following the Closing Date, and
         continuing through the Maturity Date.

                  Pension Plans -- employee pension benefit plans (as defined in
         Section 3 of ERISA) to which from time to time the Issuer is required
         to contribute.

                                      -10-


<PAGE>   16



                  Performance Agreement -- has the meaning set forth in Schedule
         B to the Note Purchase Agreements.

                  Permitted Investments -- (a) direct obligations of the United
         States of America (including obligations issued or held in book-entry
         form on the books of the Department of the Treasury of the United
         States of America and certificates or other instruments evidencing
         ownership interests in such direct obligations of the United States of
         America such as CATS, TIGRS, Treasury Receipts and Stripped Treasury
         Coupons) which mature within one (1) year after the acquisition
         thereof; (b) obligations for which the timely payment of the principal
         thereof are fully guaranteed by the United States of America or the
         Federal Deposit Insurance Corporation, which mature within one (1) year
         after the acquisition thereof; (c) certificates of deposit of, or time
         deposits in, any bank (including any Trustee) or trust company
         organized under the laws of the United States of America or any state
         thereof whose unsecured obligations are accorded one of the two highest
         ratings by Standard & Poor's Ratings Services, a division of The McGraw
         Hill Companies, Inc. or Moody's Investors Service, Inc. and which have
         capital and unimpaired surplus of at least Five Hundred Million Dollars
         ($500,000,000), maturing within ninety (90) days after the acquisition
         thereof; (d) readily marketable commercial paper of corporations doing
         business in and incorporated under the laws of the United States of
         America or any State thereof given on the date of the investment a
         credit rating of at least P-1 by Moody's Investor Services, Inc., or
         A-1 by Standard & Poor's Ratings Services, a division of The McGraw
         Hill Companies, Inc. in each case due within 90 days after the date of
         the making of the investment; and (e) investments in a money-market
         fund (including any fund for which the Trustee or any Affiliate of the
         Trustee serves as adviser or sponsor or otherwise receives compensation
         with respect to such fund) rated AAAm or better by Standard & Poor's
         Ratings Services, a division of The McGraw Hill Companies, Inc. or Aaa
         by Moody's Investors Services, Inc. (or equivalent categories that may
         be established by such rating services).

                  Person -- an individual, partnership, corporation, limited
         liability company, trust, unincorporated association or organization,
         government, governmental agency or governmental subdivision.

                  Plans -- employee benefit plans (as defined in Section 3(3) of
         ERISA) sponsored, maintained or contributed to by the Issuer or an
         ERISA Affiliate.

                  Pledged Equipment -- has the meaning set forth in Paragraph
         (a) of the Granting Clause.

                  Property -- any interest in any kind of property or asset,
         whether real, personal or mixed, and whether tangible or intangible.

                  Purchasers -- each Person named in Schedule A to the Note
         Purchase Agreements.

                  QPAM -- a "qualified professional asset manager" under Part V
         of the QPAM Exemption.


                                      -11-


<PAGE>   17



                  QPAM Exemption -- has the meaning set out in Schedule B to the
         Note Purchase Agreements.

                  Regulatory Change -- means, relative to any Credit Support
         Party: any change in (or the adoption, implementation, change in phase
         in or commencement of effectiveness of) any (i) United States federal
         or state law or foreign law applicable to such Credit Support Party;
         (ii) regulation, interpretation, directive, requirement or request
         (whether or not having the force of law) applicable to such Credit
         Support Party of any court, government authority charged with the
         interpretation or administration of any law referred to in clause (i)
         above or of any fiscal, monetary or other authority having jurisdiction
         over such Credit Support Party; (iii) GAAP or regulatory accounting
         principles applicable to such Credit Support Party; or (iv) any change
         in the application to such Credit Support Party of any existing law,
         regulation, interpretation, directive, requirement, request or
         accounting principles referred to in clause (i), (ii) or (iii) above.

                  Required Holders -- at any time, holders of more than
         fifty-one percent (51%) in aggregate principal amount of all of the
         Series A Notes then Outstanding and fifty-one percent (51%) in
         aggregate principal amount of all Series B Notes then Outstanding (in
         each case, exclusive of any Notes held by the Issuer or any Affiliate
         of the Issuer).

                  Responsible Officer -- with respect to any corporation, the
         chairman or a vice chairman of the board (if an officer), the
         president, the chief executive officer, the chief financial officer,
         the chief operating officer, executive vice president, senior vice
         president, second vice president or any other vice president, the
         controller, the treasurer, any assistant treasurer or the secretary;
         and with respect to any Trustee which is a corporation or banking
         association, any vice president, corporate trust officer or other
         officer, in each case employed within the corporate trust department of
         such Trustee.

                  SDDI -- has the meaning set out in Schedule B to the Note
         Purchase Agreements.

                  SDDI Acknowledgment and Consent -- has the meaning set out in
         Schedule B to the Note Purchase Agreements.

                  Security -- has the same meaning as in Section 2(1) of the
         Securities Act of 1933, as amended.

                  Series A Notes -- has the meaning set out in Section 2.1(a).

                  Series B Notes -- has the meaning set out in Section 2.1(b).

                  Shell Contract -- has the meaning set out in Schedule B to the
         Note Purchase Agreements.

                  Shortfall -- has the meaning set out in Section 7.8.


                                      -12-


<PAGE>   18



                  Subsidiary -- has the meaning set out in Schedule B to the
         Note Purchase Agreements.

                  Transaction Document -- has the meaning set out in Section
         3.8(b).

                  Trust Estate -- has the meaning set out in the Granting Clause
         hereof.

                  Trustee -- has the meaning set out in the first paragraph of
         this Indenture.

                  Trustee Security Document -- has the meaning set out in
         Section 10.2.

                  UCC -- has the meaning set out in Section 6.4.

                  Voting Stock -- capital stock of any class or classes of a
         corporation the holders of which are ordinarily, in the absence of
         contingencies, entitled to elect a majority of the corporate directors
         (or Persons performing similar functions).

                  Working Capital Fund -- has the meaning set out in Section
         7.15.

                  Written Request -- with respect to any Person a written order
         or request signed in the name of such Person by a Responsible Officer
         of such Person (if a corporation) or a general or managing partner (if
         a partnership) or the manager if a limited liability company or the
         individual (if an individual).

                  Year 2000 Problem -- the risk that computer hardware or
         software applications or other data processing capacities used by the
         Issuer may be unable to recognize and perform properly date-sensitive
         functions involving certain dates before and any date after December
         31, 1999.

                  Yield Protection Amount -- has the meaning set out in Section
         3.8(b).


ARTICLE 2.        FORM, EXECUTION, ISSUE AND DELIVERY OF NOTES.

         2.1      Issue of Notes.

                  (a) The Issuer has authorized the issue and sale of
         Ninety-Five Million, Four Hundred and Twelve Thousand, Five Hundred
         Dollars ($95,412,500) aggregate original principal amount of its
         ______% Series A Senior Secured Notes due _________ (such notes and all
         notes given in substitution or exchange therefore are herein
         collectively called the "Series A Notes"). The Series A Notes shall be
         issuable as fully registered Notes in the form
         set out in Annex A-1 to this Indenture.

                  (b) The Issuer has also authorized the issue and sale of
         Sixteen Million, Eight Hundred Thirty-Seven Thousand, Five Hundred
         Dollars ($16,837,500) aggregate original principal amount of its ____%
         Series B Senior Secured Notes due ______ (such notes and


                                      -13-


<PAGE>   19



         all notes given in substitution or exchange therefor are herein
         collectively called the "Series B Notes"). The Series B Notes shall be
         issuable as fully registered Notes in the form set out in Annex A-2 of
         this Indenture.

         2.2      Authentication of Notes; Denominations of Notes and Form.

                  (a) Authentication. The Notes shall be of the tenor and
         purport above recited, and the maturity date of each series of Notes
         shall be determined, on or prior to the initial issuance of such
         series, in the manner contemplated by the Note Purchase Agreements.
         Only such of the Notes as shall bear thereon a certificate in form
         substantially as set forth in the form of Trustee's Certificate of
         Authentication contained in Annex A-1 or Annex B-2, as the case may be,
         executed by the Trustee, shall be valid or become obligatory for any
         purpose or entitle the holder thereof to any right or benefit under
         this Indenture, and the Certificate of Authentication by the Trustee
         upon any such Note executed on behalf of the Issuer as aforesaid shall
         be conclusive evidence that the Note so authenticated has been duly
         authenticated and delivered hereunder and that the holder is entitled
         to the benefits of this Indenture. Subject to the provisions of Section
         2.9 respecting Notes issued in replacement of lost or stolen Notes, the
         aggregate principal amount of all Notes which may be issued and
         outstanding under this Indenture at any time shall not exceed One
         Hundred Twelve Million, Two Hundred Fifty Thousand Dollars
         ($112,250,000) less the aggregate amount of prepayments of principal
         made on the Notes up to such time.

                  (b) Denominations. The Notes shall be issued in minimum
         denominations of Five Hundred Thousand Dollars ($500,000); provided,
         however, that if it is necessary to enable the registration of transfer
         by a holder of its entire holding of Notes, a Note may be in a
         denomination which is less than Five Hundred Thousand Dollars
         ($500,000).

                  (c) Form. All Notes shall be issued in the form of Definitive
         Notes, duly executed by the Company and authenticated by the Trustee as
         hereinabove provided.

         2.3 Registration of Notes. All Notes issuable under this Indenture
shall be registered Notes. The Issuer shall cause to be kept at its agency,
maintained pursuant to Section 7.9, a register for the registration and transfer
of Notes. The name and address of each holder of record of one or more Notes,
each registration of transfer thereof and the name and address of each
transferee of one or more Notes shall be registered in such register. The Person
in whose name any Note shall be registered shall be deemed and treated as the
owner and holder thereof for all purposes of this Indenture, and the Issuer and
the Trustee shall not be affected by any notice or knowledge to the contrary.

         2.4 Exchange of Notes. Upon surrender of any Note at the agency of the
Issuer maintained pursuant to Section 7.9, the Issuer, at the request of the
holder thereof, will execute and deliver, at the Issuer's expense (except as
provided in Section 2.6 below), and the Trustee will authenticate, one or more
new Notes payable to such holder in exchange therefor, of like tenor for a like
aggregate principal amount in authorized denominations.


                                      -14-


<PAGE>   20
         2.5 Transfer of Notes.

                  (a) General. Any Note may be transferred at the agency of the
         Issuer maintained pursuant to Section 7.9, by surrendering such Note
         for cancellation, accompanied by a written instrument of transfer in a
         form reasonably satisfactory to the Issuer and the Trustee (which must
         specify the taxpayer identification number of the transferee), duly
         executed by the holder of such Note or by its attorney duly authorized
         in writing. Thereupon the Issuer, at its expense, shall issue in the
         name of the transferee or transferees, and arrange for the
         authentication by the Trustee of (and the Trustee shall authenticate)
         and deliver in exchange therefor, a new Note or Notes, of a like tenor
         for a like aggregate principal amount, in authorized denominations.

                  (b) Legends. Each Note shall bear a legend in substantially
         the following form:

                  "THE SECURITY (OR ITS PREDECESSOR) EVIDENCED HEREBY WAS
                  ORIGINALLY ISSUED IN A TRANSACTION EXEMPT FROM REGISTRATION
                  UNDER SECTION 5 OF THE UNITED STATES SECURITIES ACT OF 1933,
                  AS AMENDED (THE "SECURITIES ACT"), AND THE SECURITY EVIDENCED
                  HEREBY MAY NOT BE OFFERED, SOLD OR OTHERWISE TRANSFERRED IN
                  THE ABSENCE OF SUCH REGISTRATION OR AN APPLICABLE EXEMPTION
                  THEREFROM. THE HOLDER OF THE SECURITY EVIDENCED HEREBY IS
                  HEREBY NOTIFIED THAT THE ISSUER IS NOT REQUIRED TO REGISTER
                  THE NOTES UNDER THE SECURITIES ACT. THE HOLDER OF THE SECURITY
                  EVIDENCED HEREBY AGREES FOR THE BENEFIT OF THE COMPANY THAT
                  SUCH SECURITY MAY BE RESOLD, PLEDGED OR OTHERWISE TRANSFERRED,
                  ONLY IN ACCORDANCE WITH AN EXEMPTION FROM THE REGISTRATION
                  REQUIREMENTS OF THE SECURITIES ACT OR PURSUANT TO AN EFFECTIVE
                  REGISTRATION STATEMENT AND, IN EITHER CASE, IN ACCORDANCE WITH
                  THE APPLICABLE SECURITIES LAWS OF ANY STATE OF THE UNITED
                  STATES OR ANY OTHER APPLICABLE JURISDICTION."

                  (c) Subsequent Transferee Representations. Any transferee, by
         its acceptance of a Note registered in its name (or the name of its
         nominee), shall be deemed to have made the representations set forth in
         Sections 6.1 and 6.2 of the Note Purchase Agreements, provided,
         however, that, such transferee will not be deemed to have made the
         representation set forth in Section 6.2(c), (d) or (g) unless such
         transferee shall have made the disclosures referred to therein to the
         Issuer at least five Business Days prior to its acceptance of such Note
         and shall have received prior to such acceptance of such Note a
         certificate from the Issuer stating that (1) the Issuer is neither a
         "party in interest" (as defined in Section 3(14) of ERISA) nor a
         "disqualified person" (as defined in Section 4975(e)(2) of the Code),
         with respect to any plan identified pursuant to Section 6.2(c) or (g)
         or (2) with respect to any plan identified pursuant to Section 6.2(d)
         neither the Issuer nor any "affiliate" (as defined in Section V(e) of
         the QPAM Exemption) has at such time, or has exercised during the
         immediately preceding one year, the authority to appoint or terminate
         the QPAM as manager of the assets of any plan identified in writing
         pursuant to Section 6.2(d) or to negotiate the terms of said QPAM's
         management agreement on behalf of any such identified plan, and
         provided, further, that, such transferee will not be deemed to have
         made the representation set forth in Section 6.2(b), (c) or (d) unless
         the applicable Prohibited Transaction Class Exemption referred to
         therein remains in effect at that time or another similar Prohibited
         Transaction Class Exemption is then available. The Issuer shall
         exercise reasonable due diligence as is necessary to respond to any
         such disclosure, provided that, if the Issuer shall not respond within
         five Business Days following receipt of any such disclosure, it shall
         be deemed to

                                      -15-


<PAGE>   21



         have made the statement set forth in either clause (1) or (2), as
         applicable, of this Section 2.5(c). If the Issuer shall respond within
         five Business Days following receipt of any such prospective transferee
         disclosure and shall state that the Issuer is unable to make the
         statement set forth in either clause (1) or (2), as applicable, of this
         Section 2.5(c) (which statement shall include a description of the
         basis for its determination), the Trustee shall not be permitted (and
         the Issuer shall not be required) to register the transfer to such
         prospective transferee of the Note.

         2.6      General Rules.

                  (a) All transfers, exchanges or replacements of Notes pursuant
         to Section 2.4, Section 2.5 or Section 2.9 shall be made without
         expense to the holder of the Notes, except that any stamp taxes or
         other governmental charges required to be paid with respect to the same
         shall be paid by the Note Holder requesting such transfer, exchange or
         replacement as a condition precedent to the exercise of such privilege,
         unless an Indenture Event of Default has occurred and is continuing, in
         which case Issuer shall be liable for such stamp taxes or other
         governmental charges. All Notes surrendered for transfer, exchange or
         replacement shall be canceled and destroyed by the Trustee. Each new
         Note delivered pursuant to Section 2.4 or Section 2.5 shall be dated
         and bear interest from the most recent date to which interest has been
         paid on the surrendered Note or Notes, or dated the date of the
         surrendered Note or Notes if no interest has been paid thereon. The
         Trustee shall make a notation on each new Note delivered pursuant to
         Section 2.4, Section 2.5 or Section 2.9 of the amount of all payments
         of principal previously made on the old Note or Notes with respect to
         which such new Note is issued. The Issuer may deposit fully executed
         but unauthenticated Notes with the Trustee, which shall hold such Notes
         (as agent of the Issuer) for subsequent authentication and issuance and
         delivery by the Issuer pursuant to this Article 2. The Issuer shall not
         be required to register the transfer, exchange or replacement of,
         pursuant to this Article 2, (i) any Note during the five (5) days
         preceding the due date of any payment thereon or (ii) any Note after
         the Issuer shall have given notice pursuant to Article 3 of this
         Indenture of the prepayment thereof and prior to the prepayment date
         specified in such notice.

                  (b) With respect to the CP Conduit as a Purchaser, each holder
         of a Note, by its acceptance of said Note, hereby agrees that until the
         368th day following the maturity of the last maturing commercial paper
         note to be issued by the CP Conduit in connection with its funding of
         its investment in the Notes, no holder of a Note will institute, nor
         will said holder join with others in instituting, any involuntary
         bankruptcy or analogous proceeding against the CP Conduit under any
         bankruptcy, reorganization, receivership or similar law, domestic or
         foreign, as now or hereafter in effect.

         2.7 Valid Obligations. All Notes executed, authenticated and delivered
in exchange for, upon transfer of, or in replacement of, other Notes as provided
in this Indenture shall be the valid obligations of the Issuer, evidencing the
same debt as such other Notes, and shall be entitled to the benefits of this
Indenture to the same extent as the Notes in exchange for or upon transfer or
replacement of which they were executed and delivered.


                                      -16-


<PAGE>   22



         2.8 Execution and Delivery. The Notes may be typewritten, printed or
lithographed or produced by any other means acceptable to the Trustee, and shall
be signed on behalf of the Issuer by the manual signature of one of the
Responsible Officers under its corporate seal (which may be printed, engraved or
otherwise reproduced thereon or affixed thereto) and attested by the manual
signature of the Secretary or one of the Assistant Secretaries of the Issuer. In
the case that any of the officers who shall have signed or sealed any of the
Notes shall cease to be such officer or officers of the Issuer before the Notes
so signed or sealed shall have been delivered by or on behalf of the Issuer,
such Notes may nevertheless be delivered and issued and, upon such delivery and
issue, shall be binding upon the Issuer as though those who signed or sealed the
same had continued to be such officer or officers.

         2.9 Replacement of Notes. Upon receipt by the Issuer and the Trustee of
evidence reasonably satisfactory to each of them of the ownership of and the
loss, theft, destruction or mutilation of any Note and

                  (a) in the case of loss, theft or destruction, (i) if the
         holder is a Purchaser, its nominee or other nationally recognized bank,
         insurance company, benefit society or other institutional investor,
         upon receipt of an unsecured indemnity agreement signed by the holder
         of the Note in form reasonably satisfactory to the Issuer and the
         Trustee to save each of them harmless, or (ii) otherwise, upon receipt
         of such security or indemnity as may be reasonably required by the
         Issuer or the Trustee to save each of them harmless, or

                  (b) in the case of mutilation, upon surrender and cancellation
         thereof, the Issuer, at its own expense, will execute and deliver in
         lieu thereof, and arrange for the authentication by the Trustee of (and
         the Trustee will authenticate), a new Note of like tenor, dated and
         bearing interest from the date to which interest has been paid on such
         lost, stolen, destroyed or mutilated Note or dated the date of such
         lost, stolen, destroyed or mutilated Note if no interest has been paid
         thereon.

ARTICLE 3.        PAYMENTS AND DISTRIBUTION THEREOF.

         3.1 Payment by Issuer. Anything in this Indenture or in the Notes to
the contrary notwithstanding, but subject to the provisions of Section 12.5
hereof, the Issuer will pay all amounts payable with respect to the Notes held
by each Purchaser or other registered holder of Notes (without any presentment
of any such Notes and without any notation of such payment being made thereon)
in lawful money of the United States of America to the Trustee for payment on
behalf of the Issuer as provided in this Article 3 and in Article 4. In any case
where the date of maturity of principal of, and interest and any applicable
Make-Whole Amount, Yield Protection Amount or Breakage Amount on, the Notes or
the date fixed for any prepayment (in whole or in part) of the Notes will not be
a Business Day, then payment of such principal of, and interest and any
applicable Make-Whole Amount, Yield Protection Amount or Breakage Amount on, the
Notes need not be made on such date but may be made on the next succeeding
Business Day with the same force and effect as if made on the date of maturity
or the date fixed for such prepayment. Each holder of a Note, by its acceptance
of such Note, agrees that (i) the Trustee, in its individual capacity, shall not
be liable to the holder of any Note for any amounts payable under any Note or
this Indenture, and

                                      -17-


<PAGE>   23



(ii) the Trustee, in its individual capacity, shall not have any liability under
this Indenture, except as provided herein.

         3.2 Delivery Expenses. If any holder of a Note shall surrender any Note
to the Issuer or to the Trustee pursuant to this Indenture, the Issuer will pay
the cost of delivering to or from such holder's home office from or to the
agency of the Issuer maintained pursuant to Section 7.9, as the case may be,
insured to such holder's satisfaction, the surrendered Note and any Note issued
in substitution or replacement for the surrendered Note.

         3.3 Issue Taxes. The Issuer will pay all taxes, assessments and charges
in connection with the issuance and sale of the Notes by the Issuer and in
connection with any modification of the Notes and will save each holder of any
Note harmless without limitation as to time against any and all liabilities with
respect to all such taxes. The obligations of the Issuer under this Section 3.3
shall survive the payment or prepayment of the Notes and the termination of this
Indenture.

         3.4 Required Payments of Notes without Premium.

                  (a) Scheduled Required Prepayments for Series A Notes. In
         addition to paying the entire outstanding principal amount of, and the
         interest due on, the Series A Notes on the Maturity Date, the Issuer
         agrees to prepay, and there shall become due and payable, principal
         amounts of the Series A Notes (per $1,000,000 of original principal
         amount) (together with accrued interest owing thereon) on the Payment
         Dates (the first of which shall be on the twentieth (20th) day of the
         calendar month following the Closing Date) as set out on Annex B
         hereto.

                  (b) Prepayment at Par. Each such prepayment of principal made
         pursuant to Section 3.4(a) shall be at 100% of the principal amount
         prepaid, together with interest accrued thereon to the date of
         prepayment.

                  (c) Prepayment Schedules. Each Series A Note shall have
         attached thereto a prepayment schedule showing the amounts of principal
         of such Note required to be prepaid pursuant to Section 3.4(a) and the
         respective due dates of such amounts. The Trustee shall make a notation
         on the prepayment schedule attached to each new Series A Note delivered
         pursuant to Section 2.4, Section 2.5 or Section 2.9 of the amount of
         all prepayments of principal previously made on the old Series A Note
         or Notes with respect to which such new Series A Note is issued;
         provided that the failure of Trustee to make any such notation shall
         not affect the obligations of the Issuer hereunder or under such Series
         A Note.

                  (d) Required Prepayments Unaffected by Optional Prepayments.
         The Issuer's exercise of any prepayment option contained in Section 3.5
         shall be applied against the principal amount due at the Maturity Date
         and the prepayment installments, if any, in the inverse order of
         maturity, and shall not reduce the Issuer's obligation to make any
         earlier prepayment as provided in Section 3.4(a).

                  (e) Series B Notes. In addition to paying the entire
         outstanding principal amount of, and the interest due on, the Series B
         Notes on the Maturity Date, the Issuer agrees to pay,

                                      -18-


<PAGE>   24



         and there shall become due and payable, unpaid accrued interest on
         Series B Notes on the Payment Dates.

         3.5 Optional Prepayment of the Notes with Make-Whole Amount. None of
the Notes may be prepaid except as required or permitted by Section 3.4, this
Section 3.5, Section 3.6 or Section 6.2. The Issuer may prepay the Notes in
accordance with this Section 3.5 on any Payment Date.

                  (a) The Issuer may, upon notice as provided in Section 3.5(b),
         prepay all of the Notes in whole or in part, in multiples of One
         Million Dollars ($1,000,000), together with all interest accrued on the
         amount so prepaid plus the Make-Whole Amount, if any, determined for
         the prepayment date with respect to such principal amount.

                  (b) The Issuer will give (or cause to be given) notice of any
         optional prepayment of the Notes to the Trustee and to each holder of
         the Notes not less than thirty (30) days nor more than sixty (60) days
         before the date fixed for prepayment, specifying (i) such date, (ii)
         the Section of this Indenture under which such prepayment is to be
         made, (iii) the principal amount of such holder's Notes to be prepaid
         on such date, in the case of partial prepayments, and (iv) the interest
         to be paid on the prepayment date with respect to such principal amount
         being prepaid and shall be accompanied by a certificate of a
         Responsible Officer as to the estimated Make-Whole Amount, if any, due
         in connection with such prepayment (calculated as if the date of such
         notice were the date of the prepayment), setting forth the details of
         such computation. Two Business Days prior to such prepayment, the
         Issuer shall deliver to the Trustee and each holder of Notes a
         certificate of a Responsible Officer specifying in reasonable detail
         the calculation of such Make-Whole Amount as of the specified
         prepayment date. Notice of prepayment having been so given, the
         aggregate principal amount of the Notes specified in such notice,
         together with the Make-Whole Amount, if any, and accrued interest on
         such principal amount shall become due and payable on the specified
         prepayment date.

                  (c) Upon any partial prepayment of the Notes, the principal
         amount so prepaid shall be allocated to all Notes at the time
         Outstanding in proportion to the respective outstanding principal
         amounts thereof, with adjustments to avoid fractions of one dollar
         ($1).

         3.6 Required Prepayments of Notes. The Notes shall be prepaid in full,
together with accrued interest thereon to the date of prepayment and (with
respect to clause 3.6(a) only) the Breakage Amount, if any, and (with respect to
clause 3.6(b) only) the Make-Whole Amount, if any, determined for the prepayment
date with respect to the principal amount plus all other amounts payable
hereunder to the holders of the Notes and the Trustee:

                  (a) Upon the occurrence of an Event of Loss; or

                  (b) Upon the early termination of the Shell Contract as
         provided in Section 17E of the Drilling Order.


                                      -19-


<PAGE>   25



         The Issuer will give (or cause to be given) notice of such prepayment
under clause (a) or (b) of this Section 3.6 to the Trustee and the holders of
the Notes promptly (and in any event within one (1) Business Day) after the
occurrence of an Event of Loss or the early termination of the Shell Contract
under Section 17E of the Drilling Order, as the case may be, and shall specify
the date for such prepayment, which date shall not be less than 30 days nor more
than 45 days after the date of such notice, together with the other information
specified in Section 3.5(b). In the event the Trustee and the Note Holders have
not received the aforesaid notice, such prepayment shall be due and payable 30
days after the occurrence of the event listed in (a) or (b) above.

         3.7 Surrender of Notes on Prepayment. Following any prepayment of any
Note pursuant to Section 3.5 or Section 3.6, such Note shall, prior to any
transfer thereof, be (a) made available to the Trustee for notation on the
prepayment schedule attached to such Note of the amount of principal so prepaid
or, (b) at the option of the holder thereof and in lieu of the alternative in
the foregoing clause (a) of this sentence, held by the holder of such Note who
shall make a notation on such schedule of the amount of principal so prepaid. In
case the entire principal amount of any Note is prepaid or paid, such Note shall
be surrendered promptly at the agency of the Issuer maintained pursuant to
Section 7.9, for cancellation, upon Written Request therefor by the Issuer, and
shall not be reissued, and no Note shall be issued in lieu of the prepaid or
paid principal amount of any Note.

         3.8 Provision for Applicable Make-Whole Amount, Yield Protection
             Amount and Breakage Amount.

         (a) Applicable Make-Whole Amount. The Issuer acknowledges that the
right of each holder of a Note to maintain a rate of return based upon the full
term of the Notes and the scheduled prepayments under Section 3.4 is a valuable
right, and that the provisions for payment of the Make-Whole Amount by the
Issuer in the event that (a) the Notes are otherwise prepaid, or (b) the
maturity of the Notes is accelerated, are intended to provide reasonable
compensation for the deprivation of such right under such circumstances.

         The term "MAKE-WHOLE AMOUNT" means, with respect to any Note, an amount
equal to the excess, if any, of the Discounted Value of the Remaining Scheduled
Payments with respect to the Called Principal of such Note over the amount of
such Called Principal, provided that the Make-Whole Amount may in no event be
less than zero. For the purposes of determining the Make-Whole Amount, the
following terms have the following meanings:

                  "CALLED PRINCIPAL" means, with respect to any Note, the
         principal of such Note that is to be prepaid pursuant to Section 3.5 or
         3.6(b) or has become or is declared to be immediately due and payable
         pursuant to Section 6.2, as the context requires.

                  "DISCOUNTED VALUE" means, with respect to the Called Principal
         of any Note, the amount obtained by discounting all Remaining Scheduled
         Payments with respect to such Called Principal from their respective
         scheduled due dates to the Settlement Date with respect to such Called
         Principal, in accordance with accepted financial practice and at a
         discount factor (applied on the same periodic basis as that on which
         interest on the Notes is payable) equal to the Reinvestment Yield with
         respect to such Called Principal.


                                      -20-


<PAGE>   26



                  "REINVESTMENT YIELD" means, with respect to the Called
         Principal of any Note, .32% (with respect to the Series A Notes) and
         .32% (with respect to the Series B Notes) over the yield to maturity
         implied by (i) the yields reported, as of 10:00 A.M. (New York City
         time) on the second Business Day preceding the Settlement Date with
         respect to such Called Principal, on the display designated as "Page
         678" on the Telerate Access Service (or such other display as may
         replace Page 678 on Telerate Access Service) for actively traded U.S.
         Treasury securities having a maturity equal to the Remaining Average
         Life of such Called Principal as of such Settlement Date, or (ii) if
         such yields are not reported as of such time or the yields reported as
         of such time are not ascertainable, the Treasury Constant Maturity
         Series Yields reported, for the latest day for which such yields have
         been so reported as of the second Business Day preceding the Settlement
         Date with respect to such Called Principal, in Federal Reserve
         Statistical Release H.15 (519) (or any comparable successor
         publication) for actively traded U.S. Treasury securities having a
         constant maturity equal to the Remaining Average Life of such Called
         Principal as of such Settlement Date. Such implied yield will be
         determined, if necessary, by (a) converting U.S. Treasury bill
         quotations to bond-equivalent yields in accordance with accepted
         financial practice and (b) interpolating linearly between (1) the
         actively traded U.S. Treasury security with the duration closest to and
         greater than the Remaining Average Life and (2) the actively traded
         U.S. Treasury security with the duration closest to and less than the
         Remaining Average Life.

                  "REMAINING AVERAGE LIFE" means, with respect to any Called
         Principal, the number of years (calculated to the nearest one-twelfth
         year) obtained by dividing (i) such Called Principal into (ii) the sum
         of the products obtained by multiplying (a) the principal component of
         each Remaining Scheduled Payment with respect to such Called Principal
         by (b) the number of years (calculated to the nearest one-twelfth year)
         that will elapse between the Settlement Date with respect to such
         Called Principal and the scheduled due date of such Remaining Scheduled
         Payment.

                  "REMAINING SCHEDULED PAYMENTS" means, with respect to the
         Called Principal of any Note, all payments of such Called Principal and
         interest thereon that would be due after the Settlement Date with
         respect to such Called Principal if no payment of such Called Principal
         were made prior to its scheduled due date, provided that if such
         Settlement Date is not a date on which interest payments are due to be
         made under the terms of the Notes, then the amount of the next
         succeeding scheduled interest payment will be reduced by the amount of
         interest accrued to such Settlement Date and required to be paid on
         such Settlement Date pursuant to Sections 3.5, 3.6(b) or 6.2.

                  "SETTLEMENT DATE" means, with respect to the Called Principal
         of any Note, the date on which such Called Principal is to be prepaid
         pursuant to Section 3.5 or 3.6(b) or has become or is declared to be
         immediately due and payable pursuant to Section 6.2, as the context
         requires.

         (b) Yield Protection Amount. If any Regulatory Change occurring after
the date hereof:

                  (i) shall subject any Credit Support Party to any tax, duty or
         other charge with respect to any Series B Note (or its participation
         therein), or any of its obligations or right to

                                                      -21-


<PAGE>   27



         acquire or hold any Series B Note or to provide funding, liquidity,
         credit or asset purchase support to the CP Conduit in respect of any of
         the foregoing (or with respect to its participation in any of the
         foregoing), or shall change the basis of taxation of payments to the
         Credit Support Party of the principal or interest on any Series B Note
         (or its participation in any of the foregoing) or any other amounts due
         hereunder or under any funding, liquidity, or credit support agreement
         it may have with the CP Conduit (collectively, a "Transaction
         Document") or its obligations or rights, if any, to acquire or
         participate in any Series B Note or to provide funding, liquidity,
         credit or asset purchase support to the CP Conduit in respect of any of
         the foregoing (or with respect to its participation in any of the
         foregoing) (except for changes in the rate of tax on or determined by
         reference to the overall net income of such Credit Support Party
         imposed by the United States of America); or

                  (ii) shall impose upon any Credit Support Party, modify or
         deem applicable any reserve, special deposit or similar requirement
         against assets of any Credit Support Party, deposits or obligations
         with or for the account of any Credit Support Party or with or for the
         account of any Affiliate (or entity deemed by the Federal Reserve Board
         to be an Affiliate) of any Credit Support Party, or credit extended by
         any Credit Support Party; or

                  (iii) shall change the amount of capital maintained or
         required or requested or directed to be maintained by any Credit
         Support Party; or

                  (iv) shall impose any other condition affecting any Series B
         Note (or its participation therein) or any of its obligations or right
         to acquire or hold any Series B Note or to provide funding, liquidity,
         credit or asset purchase support to the CP Conduit in respect of any of
         the foregoing (or with respect to its participation in any of the
         foregoing);

and the result of any of the foregoing is or would be

                  (I) to increase the cost to (or impose a cost on) (I) a Credit
         Support Party funding or acquiring or holding any Series B Note, or
         loans or other extensions of credit under any Transaction Document or
         any obligation or commitment of such Credit Support Party with respect
         to any of the foregoing, or (II) a Credit Support Party for continuing
         its relationship with the CP Conduit,

                  (II) to reduce the amount of any sum received or receivable by
         a Credit Support Party as successor in interest to the CP Conduit as a
         Series B Note Holder under this Indenture, or under any Transaction
         Document (or its participation in any of the foregoing), or

                  (III) to reduce the rate of return on the capital of such a
         Credit Support Party as a consequence of its obligations under the
         Transaction Documents (or its participation therein) to a level below
         that which such Credit Support Party could otherwise have achieved,

in each such case by an amount reasonably deemed by such Credit Support Party to
be material, then prior to the next scheduled Payment Date, and in any case
within 30 days after demand by such Credit Support Party (which demand shall be
accompanied by a statement setting forth in reasonable

                                      -22-


<PAGE>   28



detail the basis of such demand), the Issuer shall pay directly to the Trustee
for the benefit of such Credit Support Party such additional amount or amounts
as will compensate such Credit Support Party for such additional or increased
cost or such reduction (the "Yield Protection Amount"). The Trustee will deposit
such amounts in the Collection Account for distribution in accordance with
Article 4.

         In determining any amount provided for or referred to in this Section
3.8(b), a Credit Support Party may use any reasonable averaging and attribution
method that it (in its sole discretion) shall deem applicable. Any Credit
Support Party when making a claim under this Section 3.8(b) shall submit to the
Issuer and the Trustee a statement as to such increased cost or reduced return
(including calculation thereof in reasonable detail), which statement shall, in
the absence of error, be conclusive and binding upon the Issuer. No Credit
Support Party shall be entitled to recover any Yield Protection Amount under
this Section 3.8(b), incurred or accrued more than 180 days prior to the notice
described in this Section 3.8(b), unless (i) the Regulatory Change giving rise
to such Yield Protection Amount is retroactive in its application to said Credit
Support Party, or (ii) said Credit Support Party lacked knowledge of the
Regulatory Change.

         (c) Breakage Amount. Within 30 days after demand by the CP Conduit or
any Credit Support Party as successor in interest to the CP Conduit as a Series
B Note Holder (a "Breakage Party") (which demand shall be accompanied by a
statement in reasonable detail setting forth the basis for such demand) the
Issuer shall pay directly to the Trustee for the benefit of such Breakage Party,
such amount or amounts as shall compensate such Breakage Party for any loss,
cost or expense incurred by such Breakage Party in connection with any Hedging
Agreements, as a result of any payment of principal of any Series B Note being
received by reason of an Event of Loss. By its purchase of the Series B Notes,
the Breakage Party agrees to pay directly to the Trustee, for the benefit of the
Issuer, such amount or amounts that it may receive as breakage payments in
connection with any Hedging Agreements, as a result of any payment of principal
on any Series B Note being received by reason of an Event of Loss. The
determination by any such Breakage Party of any such loss, expense or amount
shall be presumed correct, absent manifest error. The Trustee will deposit such
amounts in the Collection Account for distribution in accordance with Article 4.


ARTICLE 4.        RECEIPT, DISTRIBUTION AND APPLICATION OF TRUST ESTATE.

         4.1 Application of Shell Contract Revenues When No Indenture Event of
Default is Continuing.

         The Trustee shall establish an account styled "Noble/Paul Romano Cash
Collateral Account" (the "Collection Account") subject to the Trustee's sole
dominion and control. Each payment to the Trustee under any Credit Document and
all payments under the Drilling Order, other than payment pursuant to Section
17E of the Drilling Order, shall be deposited with the Trustee in the Collection
Account and held in trust by it as part of the Trust Estate and, so long as no
Indenture Event of Default shall have occurred and be continuing, applied on the
next succeeding Payment Date as follows:


                                      -23-


<PAGE>   29



                  first, the amount required to reimburse any Trustee for any
         unpaid fees for its services under this Indenture and to reimburse any
         Trustee for any reasonable expenses (including reasonable external
         attorneys' fees) not previously reimbursed;

                  second, the accrued unpaid interest due and payable to the
         Note Holders on any of the Notes, allocated among the Notes pursuant to
         Section 4.5 and distributed to the Note Holders thereof;

                  third, the required prepayments of principal due and payable
         on the Series A Notes on such Payment Date, allocated among such Notes
         pursuant to Section 4.5 and distributed to the Note Holders thereof;

                  fourth, the amount required to reimburse an Indemnified Party
         or other Person entitled to reimbursement under Section 12.16 hereof
         (except to the extent already provided for in the "first" provision
         above);

                  fifth, to deposit with the Trustee any amounts previously
         withdrawn from the Debt Service Reserve Fund which have not been
         replenished;

                  sixth, the amount required to pay any Yield Protection Amount
         due to any Credit Support Party; and

                  seventh, the balance, if any, of such payment remaining shall
         be distributed to the Issuer or its assigns.

         4.2 (a) Payments in Case of an Early Termination. Each payment made by
SDDI pursuant to an early termination of the Drilling Order in accordance with
the provisions of Section 17E of the Drilling Order (an "Early Termination"),
together with the net proceeds received by the Trustee upon foreclosure or
conveyance in lieu of foreclosure of the Drilling Rig following an Early
Termination, shall be deposited with the Trustee in the Collection Account and
held in trust by it and applied when received as follows:

                  first, so much of such payment as shall be required to
         reimburse any Trustee for any unpaid fees for its services under this
         Indenture or to reimburse any Trustee for any reasonable expenses or
         indemnity amount (including reasonable external attorneys' fees) or
         other losses incurred by them (to the extent reimbursable hereunder and
         not previously reimbursed) shall be distributed to each such Trustee
         ratably, without priority of one over the other, in the proportion that
         the amount of the expenses or other loss incurred by such Trustee bears
         to the aggregate amount of such losses or expenses incurred by all such
         Trustees;

                  second, so much of such payment remaining as shall be required
         to prepay the aggregate unpaid principal amount of all Series A Notes
         then Outstanding, plus accrued but unpaid interest thereon to the date
         of distribution including interest on past due principal and, to the
         extent permitted by applicable law, on past due interest (but excluding
         any Make- Whole Amount) shall be distributed to the holders of the
         Outstanding Series A Notes;

                                      -24-


<PAGE>   30



                  third, so much of such payment remaining as shall be required
         to prepay the aggregate unpaid principal amount of all Series B Notes
         then Outstanding, plus accrued but unpaid interest thereon to date of
         distribution including interest on past due principal and, to the
         extent permitted by applicable law, on past due interest (but excluding
         any Make-Whole Amount) shall be distributed to the holders of the
         Outstanding Series B Notes;

                  fourth, so much of such payment remaining as shall be required
         to pay any applicable Make-Whole Amount due by virtue of prepayment of
         the Series A Notes shall be distributed to the holders of the Series A
         Notes;

                  fifth, so much of such payment remaining as shall be required
         to pay any applicable Make-Whole Amount due by virtue of prepayment of
         the Series B Notes shall be distributed to the holders of the Series B
         Notes; and

                  sixth, so much of such payment remaining as shall be required
         to reimburse any holders of Outstanding Notes or any Indemnified Party
         (other than any Trustee) for any reasonable expenses or indemnity
         amount (including reasonable external attorneys' fees) or other losses
         incurred by them (to the extent reimbursable hereunder and not
         previously reimbursed) shall be distributed to each holder and
         Indemnified Party ratably, without priority of one over the other, in
         the proportion that the amount of the expenses or other loss incurred
         by such holder or Indemnified Party bears to the aggregate amount of
         such losses or expenses incurred by all such holders and Indemnified
         Parties;

                  seventh, so much of such payments remaining as shall be
         required to reimburse or pay any other fee or expense to any Person
         required hereunder or under any other Credit Document, in the
         proportion that the amount of the fee or expense required to be paid
         hereunder for any Person bears to the aggregate amount of such fees or
         expenses incurred for all such Persons; and

                  eighth, so much of such payments remaining as shall be
         required to pay any applicable Yield Protection Amount shall be
         distributed to any Credit Support Party;

                  ninth, the balance, if any, of such payment remaining shall be
         distributed to the Issuer or its assigns.

         (b) Payments in Case of an Event of Loss. All payments received by the
Trustee as proceeds of insurance, condemnation, confiscation or otherwise by
reason by an Event of Loss shall be deposited with the Trustee in the Collection
Account and held in trust by it and applied when received in the same manner as
provided in Section 4.3 below, provided, however, the Make-Whole Amount payments
shall not be due.

         (c) Payments in Case of a Partial Event of Loss. In the event of any
accident, occurrence or event resulting in damage to the Drilling Rig that does
not constitute an Event of Loss (a "Partial Loss"), and so long as there is no
Indenture Event of Default that has occurred and is continuing, then the
following provisions shall apply and all proceeds of insurance by reason of such
Partial Loss

                                      -25-


<PAGE>   31



shall be payable to the Trustee as loss payee and shall be applied upon
direction by the Trustee as follows:

                           (i) To the Issuer to reimburse the Issuer for the
                  actual costs incurred by the Issuer in connection with the
                  repairs, upon receipt by the Trustee of the following:

                                    (a)     For progress payments, a certificate
                                            signed by a Responsible Officer of
                                            the Issuer certifying that all work
                                            for which reimbursement is requested
                                            has been completed as required by
                                            Section 7.3 hereof, in a good and
                                            workmanlike manner, the Issuer has
                                            expended funds in the full amount of
                                            all insurance deductibles and has
                                            obtained lien waivers with respect
                                            to any liens in excess of $100,000
                                            individually or $2,500,000 in the
                                            aggregate that could attach with
                                            respect to such work, with such
                                            certificate to include an
                                            itemization of the costs incurred by
                                            the Issuer in connection with the
                                            repairs. For all progress payments
                                            prior to completion of all required
                                            repairs the Trustee shall withhold
                                            an amount equal to 10% of the
                                            completed repair cost to be
                                            disbursed upon final payment as
                                            provided under clause (b) below.

                                    (b)     For final payment (which will
                                            include the hold back amount called
                                            for in clause (a) above), (A) a
                                            certificate signed by a Responsible
                                            Officer that all repairs have been
                                            completed as required by Section
                                            7.3, in a good and workmanlike
                                            manner, has obtained final lien
                                            waivers with respect to liens in
                                            excess of $100,000 individually or
                                            $2,500,000 in the aggregate that
                                            could attach with respect to such
                                            work, with the certificate to
                                            include an itemization of the costs
                                            incurred by the Issuer in connection
                                            with the repairs; and (B) so long as
                                            the Shell Contract is in full force
                                            and effect, an International
                                            Association of Drilling Contractors
                                            Tour Sheet executed by the Issuer
                                            and SDDI indicating that full day
                                            rate payments under the Shell
                                            Contract are accruing currently or,
                                            if the Shell Contract is terminated,
                                            a written report in form and
                                            substance satisfactory to the
                                            Required Holders prepared by a third
                                            party engineer/surveyor or loss
                                            adjustor selected by the Trustee
                                            with the consent of the Required
                                            Holders, and compensated by the
                                            Issuer, certifying that all repairs
                                            have been completed as required by
                                            Section 7.3 hereof in good and
                                            workmanlike manner and final lien
                                            waivers obtained.

                           (ii) Any insurance proceeds not paid pursuant to
                  clause (i) above shall be paid pursuant to Section 4.1 or 4.3,
                  as appropriate.


                                      -26-


<PAGE>   32



         4.3 Payments During Continuance of an Indenture Event of Default. All
monies held or realized hereunder or in connection herewith in the Collection
Account, Debt Service Reserve Fund, proceeds of insurance, or otherwise (other
than Early Termination payments provided for in Section 4.2(a)) by the Trustee
after an Indenture Event of Default shall have occurred and be continuing or
after the acceleration of the Notes pursuant to Sections 6.2(a) or (b)
(including any amounts realized by the Trustee from the exercise of any remedies
pursuant to Article 6), as well as all payments or amounts then held or
thereafter received by the Trustee as part of the Trust Estate while any such
Indenture Event of Default shall be continuing, shall be applied by the Trustee
as follows:

                  first, so much of such monies, payments or amounts as shall be
         required to reimburse any Trustee for its default administration
         services and the costs and expenses of foreclosure or suit, if any, and
         the retaking, holding, preparing for sale or other disposition of the
         Collateral and, to the extent permitted by applicable law, the
         reasonable external attorneys' fees and legal expenses incurred by any
         Trustee;

                  second, so much of such monies, payments or amounts remaining
         as shall be required to reimburse the holders of the Outstanding Notes
         for all theretofore unreimbursed payments paid by the then existing or
         prior holders of Outstanding Notes pursuant to any indemnity furnished
         to any Trustee shall be distributed to such holders ratably, without
         priority of one over the other, in the proportion that the amount of
         each such unreimbursed payment of each such holder of a Note bears to
         the aggregate amount of all such unreimbursed payments by all such
         holders of Outstanding Notes;

                  third, so much of such monies, payments or amounts remaining
         as shall be required to pay the unpaid principal balance of all of the
         Outstanding Notes, plus all accrued and unpaid interest on such
         principal, plus any applicable Make-Whole Amount shall be distributed
         to the appropriate holders of such Notes without priority of one such
         holder over another in the proportion that the amount then owed to such
         holder bears to the aggregate amount of all such obligations which are
         then due and payable;

                  fourth, so much of such monies, payments or amounts remaining
         as shall be required to reimburse any holders of the Outstanding Notes
         or any Indemnified Party for any expenses or other indemnity amount
         (including reasonable external attorneys' fees) or other losses
         incurred by them (to the extent reimbursable hereunder and not
         previously reimbursed) shall be distributed to each such holder or
         Indemnified Party, ratably, without priority of one over the other, in
         the proportion that the amount of the expenses or other loss incurred
         by such holder or Indemnified Party bears to the aggregate amount of
         such losses or expenses incurred by all such holders or Indemnified
         Party;

                  fifth, so much of such monies, payments or amounts remaining
         as shall be required to pay any other obligations of the Issuer
         hereunder (other than the obligation of the Issuer under Section
         6.4(c)) or under any other Credit Document to the holders of the
         Outstanding Notes which are then due and payable, shall be distributed
         to such holders ratably without priority of one such holder over
         another in the proportion that the amount then owed to such holder
         bears to the aggregate amount of all such obligations which are then
         due and payable;

                                      -27-


<PAGE>   33



                  sixth, so much of such monies, payments or amounts remaining
         as shall be required to pay the Series B Note Holders or any Credit
         Support Party any Yield Protection Amount and/or Breakage Amount due;

                  seventh, so much of such monies, payments or amounts remaining
         as shall be required to pay the obligations of the Issuer under Section
         6.4(c) to the holders of the Outstanding Series B Notes shall be
         distributed to such holders ratably without priority of one over the
         other in the proportion that the amount then owed to such holder bears
         to the aggregate amount of all such obligations; and

                  eighth, the balance, if any, of such monies, payments or
         amounts shall be distributed to the Issuer or its assigns.

         4.4 Amounts Held by Trustee. Any amounts held by the Trustee in the
Debt Service Reserve Fund, Working Capital Fund, or pursuant to any other
provision hereof or any provision of any other Credit Document providing for
amounts to be held by the Trustee which are not distributed pursuant to the
other provisions of this Article 4 shall be invested by the Trustee from time to
time in Permitted Investments selected by the Issuer. Unless otherwise expressly
provided in this Indenture, any income realized as a result of any such
Permitted Investment, net of the Trustee's reasonable fees and expenses in
making such Permitted Investment, shall be held and applied by the Trustee in
the same manner as the principal amount of such Permitted Investment is to be
applied and any losses, net of earnings and such reasonable fees and expenses,
shall be charged against the principal amount invested. The Trustee shall not be
liable for any loss resulting from any investment required to be made by it
under this Indenture other than by reason of its willful misconduct or gross
negligence, and any such investment may be sold (without regard to its maturity)
by the Trustee without instructions whenever the Trustee reasonably believes
that such sale is necessary to make a distribution required by this Indenture.

         4.5 Allocation of Payments. Each payment applied to the Outstanding
Notes pursuant to Articles 3 or 4 shall be allocated among the appropriate
Outstanding Notes in proportion to the respective outstanding principal amounts
thereof, with adjustments to avoid fractions of one dollar ($1). All payments of
principal of the Notes as and when called for hereunder, except those required
pursuant to Section 3.4, shall be applied against the principal amount due at
maturity and then against the last maturing prepayment installments of
principal, if any, provided for in Section 3.4.

         4.6 Method of Payment to Holders. The principal of, Yield Protection
Amount, Breakage Amount and any Make-Whole Amount and interest on, each Note and
all other amounts payable to the holders of the Notes pursuant to this Indenture
will be payable at the office of the Trustee which has been designated as the
agency of the Issuer in Section 7.9, in United States dollars in immediately
available funds, prior to 9:00 a.m. Central time, on the due date thereof.
Notwithstanding the foregoing or any provision in any Note to the contrary, the
Trustee will pay, if so requested in writing by a holder of an Outstanding Note,
all amounts payable by the Trustee hereunder to such holder, by wire transfer of
immediately available funds to an account maintained by such holder with any
other bank located in the United States. The Trustee acknowledges that the
payment instructions given in Schedule A to the Note Purchase Agreements
constitute the written

                                      -28-


<PAGE>   34



notice required by the preceding sentence to make all payments on the Notes as
provided therein. The Trustee shall institute the transfer of such funds prior
to 11:00 a.m. Central time on such due date in accordance with this section if
it has received funds prior to 9:00 a.m. Central time. If the Trustee fails to
so institute the transfer of such funds and such funds are not received prior to
the end of such due date, the Issuer agrees to compensate the Note Holders for
the loss of the use of such funds.

         4.7 Method of Payment to Issuer. Any amounts distributed hereunder by
the Trustee to the Issuer shall be paid to the Issuer or as Issuer may otherwise
direct by wire transfer of immediately available funds of the type received by
the Trustee at such office and to such account or accounts of such entity or
entities as shall be designated by notice from the Issuer to the Trustee from
time to time.

         4.8 Payments for which No Application is Otherwise Provided. Any
payments received by the Trustee for which no provision as to the application
thereof is made elsewhere in this Indenture or in any other Credit Document,
shall be distributed by the Trustee (a) to the extent received or realized at
any time prior to the payment in full of all obligations secured by this
Indenture, in the order of priority specified in Section 4.1, 4.2 or 4.3, as
appropriate, and (b) to the extent received or realized at any time after
payment in full of all such obligations: first, to any continuing amount of the
type provided in clause "first", "second" and "fourth" of Section 4.3 and
second, to the Issuer or as the Issuer may request.

ARTICLE 5.        EVIDENCE OF ACTS OF NOTE HOLDERS.

         5.1 Execution by Note Holders or Agents. Any request, consent, demand,
authorization, direction, notice, waiver or other action provided by this
Indenture to be given or taken by holders of the Notes may be embodied in and
evidenced by one or more instruments of substantially similar tenor and may be
signed or executed by such holders in person or by agent or agents duly
appointed in writing; and, except as herein otherwise expressly provided, such
action shall become effective when such instrument or instruments are delivered
to the Trustee and, where it is hereby expressly required, to the Issuer.

         5.2 Future Holders Bound. Any request, consent, demand, authorization,
direction, notice, waiver or other action of the holder of any Note shall bind
every future holder of the same Note and the holder of every Note issued upon
registration of transfer thereof or in exchange therefor or in lieu thereof, in
respect of anything done or suffered to be done by the Trustee or the Issuer in
pursuance of such action irrespective of whether or not any notation in regard
thereto is made upon such Note.

ARTICLE 6.        INDENTURE DEFAULTS - REMEDIES

         6.1 Indenture Events of Default. One or more of the following events
shall constitute an "Indenture Event of Default":

                  (a) the Issuer shall default in the payment or prepayment when
         due of any principal of, or interest, or any applicable Make-Whole
         Amount, Yield Protection Amount,


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<PAGE>   35



         or Breakage Amount on any Note, or any fees or other amount payable by
         it hereunder or under any other Credit Document and such default, other
         than a default of a payment or prepayment of principal or applicable
         Make-Whole Amount and Breakage Amount (which shall have no cure
         period), shall continue unremedied for a period of five (5) Business
         Days; or

                  (b) any representation, warranty or certification at any time
         made or deemed made herein or in any other Credit Document by the
         Issuer or the Parent, or any certificate furnished to any Purchaser or
         other holder of any Note or the Trustee pursuant to the provisions
         hereof or any other Credit Document, shall prove to have been false or
         misleading as of the time made or furnished in any material respect; or

                  (c) the Issuer shall default in the performance of any of its
         obligations under Sections 7.3(d)(ii), 7.12 and 7.14, Article 8 or any
         other Article of this Indenture other than under Article 7 (with the
         exception of Sections 7.3(d)(ii), 7.12 and 7.14) or in any obligation
         to maintain insurance as required by this Agreement or the First Naval
         Mortgage; or the Issuer shall default in the performance of any of its
         obligations under Article 7 (with the exception of Sections 7.3(d)(ii),
         7.12 and 7.14) or any other Credit Document (other than the payment of
         amounts due which shall be governed by Section 6.1(a)), and such
         default shall continue unremedied (or unwaived) by Issuer or Parent for
         a period of thirty (30) days (or, in the case of the Shell Contract (i)
         such additional time, not to exceed thirty (30) additional days, if
         Issuer or Parent has promptly commenced and is diligently pursuing a
         cure or (ii) such shorter period of time as is required to effect a
         cure under the Shell Contract for a default under the Shell Contract)
         after the earlier to occur of (x) notice thereof to the Issuer by the
         Trustee or any Note Holder and (y) the date when a Responsible Officer
         of the Issuer has actual knowledge of the existence of such default; or

                  (d) the Issuer shall admit in writing its inability to, or be
         generally unable to, pay its debts as such debts become due; or

                  (e) the Issuer shall (i) apply for or consent to the
         appointment of, or the taking of possession by, a receiver, custodian,
         trustee or liquidator of itself or of all or a substantial part of its
         property, (ii) make a general assignment for the benefit of its
         creditors, (iii) commence a voluntary case under the Federal Bankruptcy
         Code (as now or hereafter in effect), (iv) file a petition seeking to
         take advantage of any other law relating to bankruptcy, insolvency,
         reorganization, winding-up, liquidation or composition or readjustment
         of debts, (v) fail to controvert in a timely and appropriate manner, or
         acquiesce in writing to, any petition filed against it in an
         involuntary case under the Federal Bankruptcy Code, or (vi) take any
         corporate action for the purpose of effecting any of the foregoing; or

                  (f) a proceeding or case shall be commenced, without the
         application or consent of the Issuer, in any court of competent
         jurisdiction, seeking (i) its liquidation, reorganization, dissolution
         or winding-up, or the composition or readjustment of its debts, (ii)
         the appointment of a trustee, receiver, custodian, liquidator or the
         like of the Issuer of all or any substantial part of its assets, or
         (iii) similar relief in respect of the Issuer under any law relating to
         bankruptcy, insolvency, reorganization, winding-up, or composition or
         adjustment


                                      -30-


<PAGE>   36



         of debts, and such proceeding or case shall continue undismissed, or an
         order, judgment or decree approving or ordering any of the foregoing
         shall be entered and continue unstayed and in effect, for a period of
         sixty (60) days; or (iv) an order for relief against the Issuer shall
         be entered in an involuntary case under the Federal Bankruptcy Code; or

                  (g) a judgment or judgments for the payment of money in excess
         of $500,000 in the aggregate shall be rendered by a court against the
         Issuer and the same shall not be discharged (or provision shall not be
         made for such discharge), or a stay of execution thereof shall not be
         procured, within thirty (30) days from the date of entry thereof and
         the Issuer shall not, within said period of thirty (30) days, or such
         longer period during which execution of the same shall have been
         stayed, appeal therefrom and cause the execution thereof to be stayed
         during such appeal; or

                  (h) any of the Credit Documents after delivery thereof shall
         for any reason, except to the extent permitted by the terms thereof,
         cease to be in full force and effect and valid, binding and enforceable
         in accordance with their terms, or cease to create a valid and
         perfected Lien of the priority required thereby on any of the
         collateral purported to be covered thereby, or the Issuer or the Parent
         shall so state in writing; or

                  (i) the Issuer discontinues its usual business; or

                  (j) Parent, SDDI or Shell Oil Company takes, suffers or
         permits to exist any of the events or conditions referred to in
         paragraphs (d), (e), or (f) hereof; or

                  (k) an Event of Default shall occur under, and as defined in,
         the Performance Agreement or the Capital Funding Agreement (after
         delivery thereof pursuant to the terms of Section 7.8 hereof) or the
         Parent shall default in the performance of any of its covenants under
         the Operating Services Agreement, and such default shall continue
         unremedied for a period of five (5) Business Days in the case of the
         Operating Services Agreement after the earlier to occur of (i) notice
         thereof to the Parent by the Trustee or any holder of a Note, or (ii)
         the Issuer otherwise becoming aware of such default); or

                  (l) the Shell Contract shall for any reason (other than an
         early termination event as provided in Section 17E of the Drilling
         Order) terminate or cease to be in full force and effect or SDDI (or
         any other permitted assignee in accordance with the Shell Contract)
         ceases to be a party to the Shell Contract; or

                  (m) the Issuer shall cease to be a 100% owned Subsidiary of
         the Parent or the Parent shall cease to be a 100% owned Subsidiary of
         Noble Corp.; or

                  (n) The Issuer shall fail to permanently record the First
         Naval Mortgage at the Public Registry Office of the Republic of Panama
         within ninety (90) days after the date of its execution.


                                      -31-


<PAGE>   37



         6.2      Acceleration of Notes.

         (a) Acceleration by Trustee. If an Indenture Event of Default exists
under any of Subsections 6.1(d), (e) or (f), the Notes then Outstanding shall
automatically become forthwith due and payable. If any other Indenture Event of
Default exists, the Trustee upon written request of the Majority Holders, shall
declare the entire principal of and all interest accrued on all the Notes then
Outstanding and the applicable Make-Whole Amount, if any, to be, and such Notes
shall thereupon become, forthwith due and payable together with all interest
accrued thereon and the applicable Make-Whole Amount, if any. In either such
case, the Outstanding Notes shall become due and payable without any
presentment, demand, protest, notice of protest, notice of acceleration or
intention to accelerate or any other notice or declaration of any kind, all of
which are hereby expressly waived by the Issuer, and the Issuer will forthwith
pay to all holders of the Notes then Outstanding the entire principal of and
interest accrued on their respective Notes (but specifically excluding unearned
interest) and, to the extent permitted by applicable law and for the reasons set
forth in the first sentence of Section 3.8, the applicable Make-Whole Amount, if
any, for the then entire outstanding principal of the Notes as of the date of
such declaration or automatic acceleration.

         (b) Acceleration by Individual Holder. Subject to the provisions of
Section 6.3, during the existence of an Indenture Event of Default described in
Section 6.1(a) or 6.1(c) (to the extent the 6.1(c) Event of Default is with
respect to the obligation to maintain or repair the Drilling Rig or to maintain
insurance as required by this Indenture or the First Naval Mortgage or to the
obligations set forth in Sections 7.12 or 8.19) and irrespective of whether the
Trustee shall have declared all the Notes to be due and payable pursuant to
Section 6.2(a), any holder of an Outstanding Note which has not consented to a
waiver with respect to such Indenture Event of Default described in Section
6.1(a) or 6.1(c) may, at its option, by notice in writing to the Issuer and the
Trustee, declare the entire principal of, and all interest accrued on, such
holder's Notes then Outstanding and the applicable Make-Whole Amount, if any, to
be, and such holder's Notes shall thereupon become, forthwith due and payable
together with all interest accrued thereon and the applicable Make-Whole Amount,
if any, without any presentment, demand, protest, notice of protest, notice of
acceleration or intention to accelerate or any other notice or declaration of
any kind, all of which are hereby expressly waived by the Issuer, and the Issuer
shall forthwith pay to such holder the entire principal of and interest accrued
on its Notes (but specifically excluding unearned interest) and, to the extent
permitted by applicable law and for the reasons set forth in the first sentence
of Section 3.8, the amount of the applicable Make-Whole Amount, if any, for the
then entire outstanding principal of such Notes as of the date of such
declaration by such holder. Such Notes shall be surrendered by the holder
thereof upon such full payment thereof with a Written Request for such surrender
by, and at the sole cost and expense of, the Issuer.

         (c) Nonwaiver and Expenses. No course of dealing on the part of any
holder of the Notes or on the part of any Trustee nor any delay or failure on
the part of any holder of the Notes or on the part of any Trustee to exercise
any right shall operate as a waiver of such right or otherwise prejudice such
holder's rights, powers and remedies. If the Issuer fails to pay when due the
principal of, or interest, any applicable Make-Whole Amount, or Yield Protection
Amount, or Breakage Amount on any Note, or fails to comply with any other
provision of this Indenture, the Issuer will pay to the holders of the Notes and
to each Trustee, to the extent permitted by law, such further amounts as shall
be sufficient to cover such costs and expenses, including but not limited to
reasonable external

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<PAGE>   38



attorneys' fees, as may be incurred by such holder or by such Trustee, or both,
in collecting any sums due on the Notes or in otherwise enforcing any of their
rights.

         6.3 Annulment of Acceleration of Notes. If (i) a declaration is made
pursuant to Section 6.2(a) by the Trustee, then, and in every such case, the
Majority Holders may, by written instrument filed with the Issuer and the
Trustee, rescind and annul such declaration, and the consequences thereof or
(ii) a declaration is made pursuant to Section 6.2(b) by a holder of any of the
Notes, then, such holder may, by written instrument filed with the Issuer and
the Trustee, rescind and annul such declaration, and the consequences thereof;
provided, that at the time such declaration is annulled and rescinded:

                  (a) no judgment or decree has been entered for the payment of
         any monies due on or pursuant to the Notes or this Indenture;

                  (b) all arrears of interest upon all the Notes and all other
         sums payable under the Notes and under this Indenture, except any
         principal of, or interest or any applicable Make-Whole Amount on, the
         Notes which has become due and payable solely by reason of such
         declaration under Section 6.2(a) or Section 6.2(b), shall have been
         duly paid;

                  (c) each and every other Indenture Default and Indenture Event
         of Default shall have been waived pursuant to Section 10.2 or otherwise
         made good or cured;

and, provided further, that no such rescission and annulment shall (i) extend to
or affect any subsequent Indenture Default or Indenture Event of Default or (ii)
impair any right consequent thereon.

         6.4      Default Remedies.

         (a) If an Indenture Event of Default exists, each Trustee may exercise
(i) all of the rights and remedies granted to such Trustee hereunder and/or
under each of the other Credit Documents, and (ii) all of the rights and
remedies of a secured party on default under the Uniform Commercial Code in
effect in the State of New York or in effect in any other jurisdiction, the laws
of which are applicable to the Collateral (the "UCC"). Any Trustee may take
possession of all or any part of the Properties covered or intended to be
covered by the Lien created by this Indenture or by any other Credit Document,
and such Trustee may exclude the Issuer and all Persons claiming under the
Issuer wholly or partly therefrom. Without limiting the foregoing, if any
Indenture Event of Default exists, any Trustee may from time to time in its
discretion, without notice (except as expressly provided in this Section 6.4) do
any of the following:

                           (i) subject to compliance with any mandatory legal
                  requirements, take immediate possession of the Collateral, and
                  require the Issuer to, and the Issuer hereby agrees that it
                  will at its expense and upon request of any Trustee forthwith,
                  assemble all or part of the Collateral as reasonably directed
                  by such Trustee and make it available to such Trustee at a
                  place or places to be designated by such Trustee which are
                  reasonably convenient to both parties. In any event, Issuer
                  shall bear the risk of accidental loss or damage to or
                  diminution in value of the Collateral, and


                                      -33-


<PAGE>   39



                  Trustee shall have no liability whatsoever for failure to
                  obtain or maintain insurance, nor to determine whether any
                  insurance ever in force is adequate as to amount or as to the
                  risk insured.

                           (ii) either with or without taking possession and
                  either before or after taking possession, and without
                  instituting any legal proceedings whatsoever, subject to
                  compliance with any mandatory legal requirements, dispose of
                  by public or private proceedings conducted at its office, on
                  the premises of the Issuer, at any site where any Collateral
                  is located, or elsewhere, all or any part of the Collateral,
                  as a unit or in parts and separately or in combination with
                  any other Collateral, and by way of one or more contracts (it
                  being agreed that the sale of any part of the Collateral shall
                  not exhaust the Trustee's power of sale, but sales may be made
                  from time to time, and at any time, until all of the
                  Collateral has been sold or until the obligations secured by
                  this Indenture have been paid and performed in full), and at
                  any such sale it shall not be necessary to move any of the
                  Collateral to any location of sale, or to assemble, prepare in
                  any manner or exhibit any of the Collateral (the Issuer hereby
                  acknowledging that the Collateral is not of a type for which
                  moving, assembling, preparation in any manner or exhibition is
                  necessary for a commercially reasonable sale);

                           (iii) buy the Collateral, or any part thereof, at any
                  public sale;

                           (iv) buy the Collateral, or any part thereof, at any
                  private sale if the Collateral is of a type customarily sold
                  in a recognized market or is of a type which is the subject of
                  widely distributed standard price quotations;

                           (v) at its discretion, retain the Collateral in
                  satisfaction of the obligations secured by this Indenture
                  whenever the circumstances are such that any Trustee is
                  entitled to do so under the UCC or otherwise (but under no
                  circumstances will any Trustee be deemed to have elected to
                  retain the Collateral in satisfaction of such obligations
                  unless it shall have sent written notice of such election to
                  the Issuer);

                           (vi) Take possession of all books and records of
                  Issuer pertaining to the Collateral. Each Trustee shall have
                  the authority (subject to compliance with any mandatory legal
                  requirements) to enter upon any real property or improvements
                  thereon in order to obtain any such books or records, or any
                  Collateral located thereon, and remove the same therefrom
                  without liability;

                           (vii) Apply proceeds of the disposition of the
                  Collateral to the obligations hereby secured in the manner set
                  forth in the Trust Indenture and permitted by the UCC or
                  otherwise permitted by law or in equity. Such application may
                  include, without limitation, the reasonable expenses of
                  retaking, holding, preparing for sale or other disposition,
                  and the reasonable external attorneys' fees and legal expenses
                  incurred by each Trustee;


                                      -34-


<PAGE>   40



                           (viii) Appoint any Person as agent to perform any act
                  or acts necessary or incident to any sale or transfer by each
                  Trustee of the Collateral. Additionally, any sale or transfer
                  hereunder may be conducted by an auctioneer or any officer or
                  agent of each Trustee;

                           (ix) Receive, change the address for delivery, open
                  and dispose of mail addressed to Issuer, and to execute,
                  assign and endorse negotiable and other instruments for the
                  payment of money, documents of title or other evidences of
                  payment, shipment or storage for any form of Collateral on
                  behalf of and in the name of Issuer;

                           (x) Notify or require Issuer to notify account
                  debtors that the accounts have been assigned to each Trustee
                  and direct such account debtors to make payments on the
                  accounts directly to each Trustee. To the extent each Trustee
                  does not so elect, Issuer shall continue to collect the
                  accounts. Each Trustee or its designee shall also have the
                  right, in its own name or in the name of Issuer, to do any of
                  the following: (A) to demand, collect, receipt for, settle,
                  compromise any amounts due, give acquittance for, prosecute or
                  defend any action which may be in relation to any monies due
                  or to become due by virtue of, the accounts; (B) to sell,
                  transfer or assign or otherwise deal in the accounts or the
                  proceeds thereof or the related goods, as fully and
                  effectively as if each Trustee were the absolute owner
                  thereof; (C) to extend the time of payment of any of the
                  accounts, to grant waivers and make any allowance or other
                  adjustment with reference thereto; (D) to endorse the name of
                  Issuer on notes, checks or other evidences of payments on
                  Collateral that may come into possession of each Trustee; (E)
                  to take control of cash and other proceeds of any Collateral;
                  (F) to sign the name of Issuer on any invoice or bill of
                  lading relating to any Collateral, or any drafts against
                  account debtors or other Persons making payment with respect
                  to Collateral; (G) to send a request for verification of
                  accounts to any account debtor; and (H) to do all other acts
                  and things necessary to carry out the intent of this
                  Indenture; and

                           (xi) Exercise all other rights and remedies permitted
                  by law or in equity.
   
                  (b) The Issuer agrees that, to the extent notice of sale shall
         be required by law, at least ten (10) Business Days' notice to the
         Issuer of the time and place of any public sale or the time after which
         any private sale is to be made shall constitute reasonable
         notification. The Trustee shall not be obligated to make any sale of
         Collateral regardless of notice of sale having been given. The Trustee
         may adjourn any public or private sale from time to time by
         announcement at the time and place fixed therefor, and such sale may,
         without further notice, be made at the time and place to which it was
         so adjourned.

                  (c) In addition to the foregoing, in the event the Series B
         Notes are not paid and satisfied in full at maturity thereof and
         payment and satisfaction thereof is effected through realization upon
         the Collateral pursuant to this Article 6, the Series B Note Holders
         shall be entitled to additional compensation from the proceeds of such
         realization of the Collateral

                                      -35-


<PAGE>   41



         pursuant to Section 4.3 of $3,000,000 to compensate the Series B Note
         Holders for the additional risk, time and expense.

         6.5      Other Enforcement Rights.

                  (a) Each Trustee may, but unless first requested so to do by
         the Majority Holders and furnished with reasonable indemnity
         satisfactory to it pursuant to Section 9.3(f) hereof shall not (subject
         to the provisions of Section 9.1) be under any obligation to, proceed
         to protect and enforce this Indenture, the Notes and each other Credit
         Document by suit or suits or proceedings in equity, at law or in
         bankruptcy, and whether for the specific performance of any covenant or
         agreement herein or therein provided, or for foreclosure thereunder, or
         for the appointment of a receiver or receivers for the foreclosure
         thereunder, or for the appointment of a receiver or receivers for the
         Trust Estate or other Collateral or any part thereof, for the recovery
         of judgment for the obligations hereby secured or for the enforcement
         of any other proper, legal or equitable remedy available under
         applicable law.

                  (b) In case an Indenture Event of Default has occurred and is
         continuing and there shall be pending any case or proceedings for the
         bankruptcy or for the reorganization or arrangement of the Issuer, the
         Parent or SDDI, under the federal bankruptcy laws or any other
         applicable law or in connection with the insolvency of the Issuer, the
         Parent or SDDI, or in case a custodian, receiver or trustee shall have
         been appointed for the Issuer, the Parent or SDDI, or in case of any
         other proceedings in respect of the Issuer, the Parent or SDDI, the
         Trustee may file such proof of claim and other papers or documents as
         may be necessary or advisable in order to have the claims of any
         Trustee and of the Note Holders allowed in any judicial proceedings
         relative to the Issuer, the Parent or SDDI, and, irrespective of
         whether the principal of all of the Notes shall then be due and payable
         as therein expressed, by proceedings for the prepayment thereof, by
         declaration or otherwise, the Trustee shall be entitled and empowered
         to file and prove a claim for the whole amount of principal, applicable
         Make-Whole Amount (if any) and interest owing and unpaid in respect of
         the Notes, and any other sum or sums owing thereon or pursuant thereto
         or pursuant hereto, and to collect and receive any or other Property
         payable or deliverable on any such claim, and to distribute the same as
         provided in Section 4.3; and any receiver, custodian, assignee or
         trustee in bankruptcy, trustee or debtor in reorganization or trustee
         or debtor in any proceedings for the adoption of an arrangement is
         hereby authorized by each holder of any Note, by the acceptance of the
         Note or Notes held by it, to make such payments to the Trustee, and, in
         the event that the Trustee shall consent to the making of such payments
         directly to the Note Holders, to pay to each of the Trustees any amount
         due it for compensation and expenses, including reasonable external
         counsel fees, incurred by it up to the date of such distribution;
         provided, however, that nothing herein contained shall be deemed to
         authorize or empower the Trustee to consent to accept or adopt, on
         behalf of any holder of the Notes, any plan of reorganization or
         readjustment of the Issuer affecting the Notes or the rights of any
         holder thereof, or to authorize or empower the Trustee to vote in
         respect of the claim of any holder in any such proceedings.

                  (c) The Issuer hereby irrevocably appoints the Trustee as the
         Issuer's attorney-in-fact and proxy, with full authority in the place
         and stead of the Issuer and in the

                                      -36-


<PAGE>   42



         name of the Issuer or otherwise, from time to time during the
         continuance of an Indenture Event of Default in the Trustee's
         discretion, to take any action and to execute any instrument which the
         Trustee may deem necessary or advisable to accomplish the purposes of
         this Indenture, including, without limitation: (a) to ask, demand,
         collect, sue for, recover, compound, receive and give acquittance and
         receipts for monies due and to become due under or in respect of any of
         the Collateral; and (b) to file any claims or take any action or
         institute any proceedings which the Trustee may deem necessary or
         desirable for the collection of any of the Collateral or otherwise to
         enforce the rights of the Trustee with respect to any of the
         Collateral. Without limiting the generality of the foregoing and
         whether or not an Indenture Event of Default shall have occurred and be
         continuing, the Trustee shall have the right to receive, collect and
         endorse all checks made payable to the Issuer or the Issuer's order
         representing payments under the Shell Contract or any payment on
         account of any of the Collateral and to give full discharge therefor.

                  (d) If the Issuer or the Parent fails to perform any act or to
         take any action which hereunder or under any other Credit Document to
         which it is a party, the Issuer or the Parent is required to perform or
         take, or to pay any money which hereunder or under any other Credit
         Document the Issuer or the Parent is required to pay, the Trustee, in
         the Issuer's or the Parent's name or in its own name, may (but shall
         not be obligated to) following notice to the Issuer or Parent perform
         or cause to be performed such act or take such action or pay such
         money, and any expenses so incurred by the Trustee, and any money so
         paid by the Trustee, shall be a demand obligation owing by the Issuer
         and shall bear interest from the date of making such payment until paid
         at the Default Rate and shall be secured by this Indenture and by any
         other instrument securing the obligations secured hereby. Upon making
         any such payment, the Trustee shall be subrogated to all of the rights
         of the Person receiving such payment, which rights will be held by the
         Trustee to secure the obligations secured hereby.

                  (e) Anything in this Indenture to the contrary
         notwithstanding, the Majority Holders shall have the right, at any
         time, by an instrument or instruments in writing, executed and
         delivered to any Trustee and providing for indemnity satisfactory to it
         pursuant to Section 9.3(f), to direct the method and place of
         conducting all proceedings to be taken in connection with the
         enforcement of the terms and conditions of this Indenture; provided,
         however, that such direction shall not be otherwise than in accordance
         with the provisions of law and of this Indenture.

         6.6      Effect of Sale, etc.

                  (a) Any sale or sales pursuant to the provisions hereof or of
         any other Credit Document, whether under the power of sale granted
         hereby or thereby or pursuant to any legal proceedings, shall operate
         to divest the Issuer of all right, title, interest, claim and demand
         whatsoever, either at law or in equity, of, in and to the Trust Estate
         or other Collateral, or any part thereof, so sold, and any Property so
         sold shall be free and clear of any and all rights of redemption by,
         through or under the Issuer. At any such sale, the holder of any Note
         may bid for and purchase the Property sold and may make payment
         therefor as set forth below, and any Note Holder so purchasing any such
         Property, upon compliance with

                                      -37-


<PAGE>   43



         the terms of sale may hold, retain and dispose of such Property without
         further accountability.

                  (b) The receipt by any Trustee, or by any Person authorized
         under any judicial proceedings to make any such sale, of the proceeds
         of any such sale shall be a sufficient discharge to any purchaser of
         the Trust Estate or other Collateral, or of any part thereof, sold as
         aforesaid; and no such purchaser shall be bound to see to the
         application of such proceeds, or be bound to inquire as to the
         authorization, necessity or propriety of any such sale. In the event
         that, at any such sale, any holder of Outstanding Notes is the
         successful purchaser, it may, in paying the purchase price, turn in any
         of its Notes in lieu of cash in the amount which shall, upon
         distribution of the net proceeds of such sale, be payable thereon, and
         if the cash amounts so payable thereon shall be less than the amount
         due therein, said Notes shall be returned to the holders thereof after
         a notation of each partial prepayment shall have been made thereon.

         6.7 Restoration of Rights and Remedies. If any Trustee shall have
instituted any proceeding to enforce any right or remedy under this Indenture or
under any other Credit Document and such proceeding shall have been discontinued
or abandoned for any reason, or shall have been determined adversely to such
Trustee, then and in every such case such Trustee, the Issuer and the holders of
the Notes shall, subject to any determination in such proceeding, be restored
severally and respectively to their former positions hereunder or under any
other Credit Document, and thereafter all rights and remedies of such Trustee
shall continue as though no such proceeding had been instituted.

         6.8 Application of Sale Proceeds and Deficiency. The proceeds of any
exercise of rights with respect to the Trust Estate or any other Collateral, or
any part thereof, and the proceeds and the avails or any remedy hereunder shall
be paid to and applied as described in Section 4.3. In the event that at any
time and from time to time the payments under the Shell Contract then collected
by the Trustee and the proceeds of any sale, collection or realization of or
upon Collateral by the Trustee are insufficient to pay all the obligations
secured by this Indenture, the Issuer shall be liable for the deficiency,
together with interest thereon as provided in the governing Credit Documents or
(if no interest is so provided) at such other rate as shall be fixed by
applicable law, together with the costs of collection and the reasonable fees
and disbursements of any external attorneys employed by the Trustee or any
holder of an Outstanding Note to collect such deficiency.

         6.9 Cumulative Remedies. No delay or omission of any Trustee or of the
holder of any Note to exercise any right or power hereunder or under any other
Credit Document arising from any Indenture Default or Indenture Event of Default
or failure of performance on the part of the Issuer shall exhaust or impair any
such right or power or prevent its exercise during the continuance of such
Indenture Default or Indenture Event of Default. No waiver by any Trustee, or
the holder of any Note, of any such Indenture Default or Indenture Event of
Default, whether such waiver be full or partial, shall extend to or be taken to
affect any subsequent default, or to impair the rights resulting therefrom
except as may be otherwise expressly provided herein. No remedy hereunder or
under any other Credit Document is intended to be exclusive of any other remedy
but each and every remedy shall be cumulative and in addition to any and every
other remedy given hereunder or under any other Credit Document or otherwise
existing; nor shall the giving, taking or enforcement of any other

                                      -38-


<PAGE>   44



or additional security, Collateral or guaranty for the payment of the
obligations secured under this Indenture operate to prejudice, waive or affect
the security of this Indenture or any other Credit Document or any rights,
powers or remedies hereunder or under any other Credit Document, nor shall any
Trustee or any holder of any Note be required to first look to, enforce or
exhaust such other or additional security, Collateral or guaranties. All
covenants, conditions, provisions, warranties, guaranties, indemnities and other
undertakings of the Issuer contained in this Indenture, or in any document
referred to herein or in any agreement supplementary hereto or in any other
Credit Documents shall be deemed cumulative to and not in derogation or
substitution of any of the terms, covenants, conditions, or agreements of the
Issuer herein contained. To the extent of overlap of any security interest or
lien granted hereunder or under any other Credit Document on any particular
Collateral, the Trustee may elect to exercise rights and remedies under either
or, if appropriate, both of such security interests or liens.

         6.10 Limitations on Suits. Except as provided in Section 6.2(b), no
holder of any Note issued hereunder shall have the right to institute any suit,
action or proceeding at law or in equity, for the execution of any trust or
power granted to the Trustees under this Indenture or any other Credit Document
or for any other remedy under or upon this Indenture or any other Credit
Document, unless (a) the Majority Holders shall have made Written Request upon
the applicable Trustee to exercise the powers hereinbefore granted or to
institute such action, suit or proceeding in its own name; (b) such holder or
said holders shall have offered to such applicable Trustee the indemnity
reasonably satisfactory to it as provided under Section 9.3(f); and (c) such
applicable Trustee shall have refused or failed to comply with such Written
Request for a period of thirty (30) days after such Written Request shall have
been received by it. Such notification, request, offer of indemnity and refusal
or failure are hereby declared, in every case, to be conditions precedent to the
exercise by any holder of a Note of any remedy hereunder; it being understood
and intended that no one or more holders of Notes shall have any right in any
manner whatever by its or their action to enforce any right under this Indenture
or any other Credit Document, except in the manner herein provided, and that all
judicial proceedings to enforce any provision of this Indenture or any other
Credit Document shall be instituted, had and maintained in the manner herein or
any other Credit Document provided and for the equal and proportionate benefit
of all holders of the Outstanding Notes.

         6.11 Suits for Principal and Interest. Nothing contained in Section
6.10 or in any other provision of this Indenture or in the Notes shall affect or
impair the obligation of the Issuer, which is absolute and unconditional, to pay
(or cause to be paid from the Trust Estate or other Collateral as in Article 4
provided) the principal of, any applicable Make-Whole Amount and interest on,
the Notes to the holders thereof on the dates when due, respectively, and at the
place specified in Section 4.6, or affect or impair the right of action, which
is also absolute and unconditional, of such holders to institute suit to enforce
such payment by virtue of the contract embodied in the Notes.

         6.12 Waiver by the Issuer.

                  (a) In granting to the Trustee the power to enforce its rights
         hereunder without prior judicial process or judicial hearing, the
         Issuer expressly waives, renounces and knowingly relinquishes (to the
         extent it may lawfully do so) any legal right which might otherwise
         require the Trustee to enforce its rights by judicial process. In so
         providing for

                                      -39-


<PAGE>   45



         non-judicial remedies, the Issuer recognizes and concedes that such
         remedies are consistent with the usage of trade, are responsive to
         commercial necessity, and are the result of a bargain at arm's length.
         Nothing herein is intended to prevent the Trustee or the Issuer from
         resorting to judicial process.

                  (b) The Issuer by becoming a party to any Credit Document (to
         the extent that it may lawfully do so) hereby covenants that it will
         not at any time insist upon or plead, or in any manner claim or take
         the benefit or advantage of, any stay (except in connection with a
         pending appeal of a judgment in a legal proceeding), valuation,
         appraisal, redemption or extension law now or at any time hereafter in
         force which, but for this waiver, might be applicable to any sale made
         under any judgment, order or decree based on any of the Notes or this
         Indenture or any other Credit Document; and the Issuer by becoming a
         party to any Credit Document (to the extent it may lawfully do so)
         hereby expressly waives and relinquishes all benefit and advantage of
         any and all such laws and hereby covenants that it will not hinder,
         delay or impede the execution of any power herein granted and delegated
         to any Trustee, but that it will suffer and permit the execution of
         every such power as though no such law or laws had been made or
         enacted.

                  (c) The Issuer waives any right to require the Trustee or the
         holders of the Outstanding Notes to proceed against any other Person,
         or to exhaust any Collateral or other security for the obligations
         secured hereby, or to have any other Person joined with the Issuer in
         any suit arising out of such obligations or the Credit Documents, or to
         pursue any other remedy in the Trustee's or such holders' power. The
         Issuer further waives any and all notice of acceptance of this
         Indenture by any other Person directly or indirectly liable for such
         obligations from time to time. The Issuer further waives any defense
         arising by reason of any disability or other defense of any other
         Person or by reason of the cessation from any cause whatsoever of the
         liability of any other Person liable for the obligations secured
         hereby. Until all of such obligations shall have been paid in full, the
         Issuer shall have no right to subrogation and the Issuer waives the
         right to enforce any remedy which the Trustee or the holders of the
         Outstanding Notes have or may hereafter have against any other Person
         liable for such obligations, and the Issuer waives any benefit of any
         right to participate in any security whatsoever now or hereafter held
         by the Trustee or the holders of the Outstanding Notes. The Issuer
         authorizes the Trustee and the holders of the Outstanding Notes,
         without notice or demand and without any reservation of rights against
         the Issuer and without affecting the Issuer's liability hereunder or on
         the obligations secured hereby, from time to time to (a) take or hold
         any Property other than the Collateral from any other Person as
         security for such obligations, and exchange, enforce, waive and release
         any or all of such Property, (b) apply such Property and direct the
         order or manner of sale thereof as the Trustee and the Majority Holders
         may in their discretion determine, and (c) renew, extend for any
         period, accelerate, modify, compromise, settle or release any of the
         obligations of any other Person in respect of the obligations secured
         hereby or other security for such obligations.



                                      -40-


<PAGE>   46
ARTICLE 7.        AFFIRMATIVE COVENANTS.

         The Issuer covenants and agrees that, so long as any of the commitments
are in effect and until payment in full of all Notes issued hereunder, all
interest thereon and all other amounts payable by the Issuer hereunder:

         7.1 Financial Statements. The Issuer shall deliver, or shall cause to
be delivered, to the Trustee and each Note Holder:

                  (a) As soon as available and in any event within 120 days
         after the end of each fiscal year of the Issuer the audited statements
         of operations, stockholders' equity and cash flow, of the Issuer for
         such fiscal year, and the related balance sheet of the Issuer as at the
         end of such fiscal year, and setting forth in each case in comparative
         form the corresponding figures for the preceding fiscal year, and
         accompanied by (i) the related opinion of PriceWaterhouseCoopers, or
         such other independent public accountants of recognized national
         standing acceptable to the Majority Holders, which opinion shall state
         that said financial statements fairly present the financial condition
         and results of operations of the Issuer as at the end of, and for, such
         fiscal year, that such financial statements have been prepared in
         accordance with GAAP, except for such changes in such principles with
         which the independent public accountants shall have concurred and
         footnoted and such opinion shall not contain a "going concern" or scope
         or like qualification or exception and that the examination of such
         accountants in connection with such financial statements has been
         conducted in accordance with generally accepted auditing standards and
         included such tests of the accounting records and such other auditing
         procedures as said accountants deemed necessary in the circumstances
         and (ii) a certificate of such accountants stating that in making the
         examination necessary for their opinion, they obtained no knowledge,
         except as specifically stated, of any Indenture Default or Indenture
         Event of Default.

                  (b) As soon as available and in any event within 120 days
         after the end of each fiscal year of Noble Corp., the audited
         consolidated statements of operations, stockholders' equity, and cash
         flow, of Noble Corp. and its consolidated subsidiaries for such fiscal
         year, and the related balance sheet of Noble Corp. and its consolidated
         subsidiaries as at the end of such fiscal year, and setting forth in
         each case in comparative form the corresponding figures for the
         preceding fiscal year, and accompanied by the related opinion of 
         PriceWaterhouseCoopers, or such other independent public accountants of
         recognized national standing acceptable to the Majority Holders, which
         opinion shall state that said financial statements fairly present the
         consolidated financial condition and results of operations of Noble
         Corp. and its consolidated subsidiaries as at the end of, and for, such
         fiscal year, that such financial statements have been prepared in
         accordance with GAAP, except for such changes in such principles with
         which the independent public accountants shall have concurred and
         footnoted and such opinion shall not contain a "going concern" or scope
         or like qualification or exception and that the examination of such
         accountants in connection with such financial statements has been
         conducted in accordance with generally accepted auditing standards and
         included such tests of the accounting records and such other auditing
         procedures as said accountants deemed necessary in the circumstances.

                  (c) As soon as available and in any event within 120 days
         after the end of each fiscal year of the Parent, the unaudited
         consolidated statements of operations, of the Parent

                                      -41-


<PAGE>   47



         and its consolidated subsidiaries for such fiscal year and the related
         consolidated balance sheets of the Parent and its consolidated
         subsidiaries as at the end of such fiscal year, and setting forth in
         each case in comparative form, the corresponding figures for the
         preceding fiscal year, and accompanied by the certificate of a
         Responsible Officer, which certificate shall state that said financial
         statements fairly present the consolidated financial condition and
         results of operations of the Parent and its consolidated subsidiaries
         as at the end of, and for, such fiscal year and that such financial
         statements have been prepared in accordance with GAAP (exclusive of
         footnotes), as at the end of, and for, such period.

                  (d) As soon as available and in any event within 60 days after
         the end of each of the first three fiscal quarterly periods of each
         fiscal year of the Issuer the unaudited statements of operations and
         cash flows of the Issuer for such period and for the period from the
         beginning of the respective fiscal year to the end of such period, and
         the related balance sheets as at the end of such period, and setting
         forth in each case in comparative form the corresponding figures for
         the corresponding period in the preceding fiscal year, accompanied by
         the certificate of a Responsible Officer, which certificate shall state
         that said financial statements fairly present the consolidated
         financial condition and results of operations of the Issuer in
         accordance with GAAP, as at the end of, and for, such period (subject
         to normal year-end audit adjustments) and further stating whether there
         existed as of the date of such financial statements and whether, to the
         best of such officer's knowledge, there exists on the date of the
         certificate or existed at any time during the period covered by such
         financial statements any Indenture Default or Indenture Event of
         Default and, if any such condition or event exists on the date of the
         certificate, specifying the nature and period of existence thereof and
         the action the Issuer is taking and proposes to take with respect
         thereto.

                  (e) As soon as available and in any event within 60 days after
         the end of each of the first three fiscal quarterly periods of each
         fiscal year of the Parent, the unaudited consolidated statements of
         operations of the Parent and its consolidated subsidiaries for such
         period and for the period from the beginning of the respective fiscal
         year to the end of such period, and the related consolidated balance
         sheets as at the end of such period, and setting forth in each case, in
         comparative form the corresponding figures for the corresponding period
         in the preceding fiscal year, accompanied by the certificate of a
         Responsible Officer, which certificate shall state that said financial
         statements fairly present the consolidated financial condition and
         results of operations of the Parent and its consolidated subsidiaries
         in accordance with GAAP, as at the end of, and for, such period
         (subject to normal year-end audit adjustments).

                  (f) As soon as available and in any event within 60 days after
         the end of each of the first three fiscal quarterly periods of each
         fiscal year of Noble Corp. the unaudited consolidated statements of
         operations and cash flows of Noble Corp. and its consolidated
         subsidiaries for such period and for the period from the beginning of
         the respective fiscal year to the end of such period, and the related
         consolidated balance sheets as at the end of such period and setting
         forth in each case in comparative form the corresponding figures for
         the corresponding period in the preceding fiscal year.


                                      -42-


<PAGE>   48



                  (g) Within the period provided in paragraph (a) above, a
         certificate of a Responsible Officer of the Issuer stating whether
         there existed as of the date of such financial statements and whether,
         to the best of such officer's knowledge, there exists on the date of
         the certificate or existed at any time during the period covered by
         such financial statements any Indenture Default or Indenture Event of
         Default and, if any such condition or event exists on the date of the
         certificate, specifying the nature and period of existence thereof and
         the action the Issuer is taking and proposes to take with respect
         thereto.

                  (h) Promptly and in any event within three (3) Business Days
         after the Issuer knows that any Indenture Default or Indenture Event of
         Default or any Material Adverse Effect has occurred, a notice of such
         Indenture Default or Indenture Event of Default or Material Adverse
         Effect, and promptly and in any event within three (3) Business Days
         after the Issuer knows of any material default under the Shell Contract
         or the Operating Services Agreement a notice of such default, in each
         case, describing the same in reasonable detail and the action the
         Issuer proposes to take with respect thereto.

                  (i) Promptly upon its becoming available, each financial
         statement, report, notice or proxy statement sent by the Issuer, the
         Parent or Noble Corp. to stockholders generally and each regular or
         periodic report and any registration statement, prospectus or written
         communication (other than transmittal letters) in respect thereof filed
         by the Issuer, the Parent or Noble Corp. with or received by the
         Issuer, the Parent or Noble Corp. in connection therewith from any
         securities exchange or the SEC or any successor agency.

                  (j) From time to time such other information regarding the
         business, affairs or financial condition of the Issuer, the Parent or
         information from Noble Corp. reasonably related to the Issuer or the
         Parent (including, without limitation, any Plan or Multiemployer Plan
         and any reports or other information required to be filed under ERISA)
         as any Purchaser or other Note Holder or the Trustee may reasonably
         request.

         7.2 Litigation. The Issuer shall promptly give to the Trustee and each
registered Note Holder notice of any litigation or proceeding against or
adversely affecting the Issuer or the Parent in which the amount involved is not
covered in full by insurance or in which the Issuer has received notice from any
insurer reserving its rights or contesting coverage under any policy (subject to
normal and customary deductibles and for which the insurer has not assumed the
defense), or in which injunctive or similar relief is sought and which could
reasonably be expected to result in a Material Adverse Effect. The Issuer will
promptly notify the Trustee and each registered Note Holder of all claims,
judgments, Liens or other encumbrances affecting any Property of the Issuer if
the aggregate value of such claims, judgments, Liens or other encumbrances
affecting such Property shall exceed $500,000.

         7.3 Maintenance, Etc.

                  (a) The Issuer shall: (i) preserve and maintain its corporate
         existence and all of its material rights, privileges, licenses and
         franchises; (ii) keep proper books of record and account in which full,
         true and correct entries will be made of all dealings or transactions
         of, or in relation to its business and activities in accordance with
         GAAP consistently applied;

                                      -43-


<PAGE>   49



         (iii) comply with all Governmental Requirements if failure to comply
         with such requirements will have a Material Adverse Effect; (iv) pay
         and discharge all taxes, assessments and governmental charges or levies
         imposed on it or on its income or profits or on any of its Property,
         all trade accounts payable in accordance with usual and customary
         business terms and all claims for work, labor or materials prior to the
         date on which any Lien (other than Liens for obligations that have not
         been outstanding more than 60 days, unless action has been taken to
         file or enforce such Liens) or penalties attach thereto, except for any
         such tax, assessment, charge, levy, account payable or claim, the
         payment of which is being Contested In Good Faith; (v) permit any
         holder of the Notes or its representative to visit and inspect, under
         the Issuer's guidance, any of the properties of the Issuer, to examine
         all of its books of account, records, reports and other papers, to make
         copies and extracts therefrom and to discuss its affairs, finances and
         accounts with its officers, employees, and independent public
         accountants (and by this provision the Issuer authorizes said
         accountants to discuss with any holder of the Notes the finances and
         affairs of the Issuer) all at such reasonable time, upon reasonable
         notice and as often as may be reasonably requested; provided that the
         Issuer shall not be required to pay or reimburse any Note Holder for
         expenses which such holder may incur in connection with any such
         visitation or inspection, except that if such visitation or inspection
         is made during any period when an Indenture Default or an Indenture
         Event of Default shall have occurred and be continuing, the Issuer
         agrees to reimburse such holder for all such expenses promptly upon
         demand, and (vi) keep, or cause to be kept, insured by financially
         sound and reputable insurers all Property of a character usually
         insured by Persons engaged in the same or similar business similarly
         situated against loss or damage of the kinds and in the amounts
         customarily insured against by such Persons and carry such other
         insurance as is usually carried by such Persons and as required by each
         of the Shell Contract and the First Naval Mortgage including, without
         limitation, the insurance described on Schedule 7.3 hereto.

                  (b) Contemporaneously with the delivery of the financial
         statements required by Section 7.1 to be delivered for each year, the
         Issuer will furnish or cause to be furnished to the Trustee a
         certificate of insurance coverage from each insurer in form and
         substance satisfactory to the Trustee and the Required Holders.

                  (c) The Issuer will maintain the Drilling Rig and all
         equipment used in connection therewith in a good running order, repair
         and first class condition and in compliance with the Shell Contract and
         all Governmental Requirements and within the class designation as on
         the Closing Date and with all equipment capable of operation within the
         tolerances designated on the Closing Date and at all times registered
         as a vessel under the laws of Panama and otherwise operate its
         Properties or cause such Properties to be operated in United States
         territorial waters in the Gulf of Mexico or in the Gulf of Mexico on or
         above the outer Continental Shelf of the United States and as set forth
         in Section 1 of the Drilling Order and in accordance with the Shell
         Contract and the practices of the industry and in compliance with all
         other applicable contracts and agreements and otherwise in a careful
         efficient manner and in compliance in all material respects with all
         Governmental Requirements.


                                      -44-


<PAGE>   50



                  The Issuers' maintenance obligations hereunder shall include,
         without limitation, causing the surveys and inspections referred to in
         Annex D hereto to be timely conducted and satisfactorily passed with
         the 5 year surveys and inspections conducted and passed prior to the
         Maturity Date.

                  In the event of any damage to the Drilling Rig from any
         casualty having a repair cost in excess of $250,000, the Issuer shall
         give prompt written notice thereof to the Trustee, which notice shall
         set forth in reasonable detail the nature and extent of the damage, an
         estimate of the cost of repairs and an estimate of the length of time
         necessary to repair such damage. Such notice shall also state whether
         the Issuer considers such damage to constitute an Event of Loss, which
         statement shall not, however, be determinative. With respect to any
         casualty damage, regardless of whether insurance proceeds are
         available, the Issuer shall promptly and diligently repair the Drilling
         Rig or cause the Drilling Rig to be repaired to the same condition as
         it was before such damage and in compliance with the foregoing
         requirements of this Section 7.3(c), free and clear of all liens and
         encumbrances other than Excepted Liens. At the request of the Trustee,
         all contracts for any such repairs shall be assigned to the Trustee as
         part of the Trust Estate as security for Issuer's obligations
         hereunder. Such assignment may be effected by a blanket assignment and
         by specific assignments with respect to third party contracts in excess
         of $100,000. In the event of any damage that constitutes an Event of
         Loss, then the Issuer shall be relieved of the foregoing repair
         obligations upon repayment in full of all principal, interest and all
         other amounts payable under the Notes and the other Credit Documents in
         compliance with the provisions of Section 3.6 hereof.

                  (d)(i) The Issuer will maintain the Shell Contract and the
         Operating Services Agreement in full force and effect and comply with
         all terms and provisions thereof and enforce the compliance of SDDI and
         the Parent in accordance with their respective terms except for
         immaterial variances and immaterial waivers. In furtherance of the
         foregoing, Issuer shall: (A) pursue all reasonable efforts with respect
         to collecting dayrate payments due under the Shell Contract in
         accordance with prudent business practices, and (B) collect all dayrate
         payments due under the Shell Contract not later than sixty days after
         the date due, unless on such due date and continuing through and until
         the date on which such dayrate payment is made, the Debt Service
         Reserve Fund shall equal two (2) months worth of payments required on
         the Notes or, if the Capital Funding Agreement is then in effect, no
         amount shall have been drawn thereunder and not reinstated.

                  (ii) The Operating Services Agreement will not be amended or
         modified without the approval of the Required Holders. The maintenance,
         repair and insurance requirement provisions of the Shell Contract will
         not be amended or modified without the approval of the Required Holders
         and the Shell Contract will not otherwise be amended or modified
         without the approval of the Required Holders if such other amendment or
         modification will reduce or impair the rentals or other payments of
         SDDI thereunder, including, without limitation, the termination
         payments called for in Section 17E of the Drilling Order, or will
         change the payment terms or the term of the Shell Contract, or will
         increase the material obligations of the contractor thereunder or will
         otherwise materially impair the value, operational capabilities and
         useful life of the Drilling Rig or the Shell Contract. Without the
         consent of

                                      -45-


<PAGE>   51



         all of the Note Holders, the Issuer will not consent to the assignment
         by SDDI (except to permitted assignees in accordance with the Shell
         Contract) of the Shell Contract.


                  (e) Promptly after the submission to SDDI of each monthly
         billing under the Shell Contract, the Issuer shall supply the Trustee
         with a copy thereof, which billing shall clearly set out the amount of
         the billing and the due date thereof.

         7.4 Environmental Matters.

                  (a) The Issuer will operate the Property in compliance with
         Environmental Laws such that any noncompliance will not have a Material
         Adverse Effect, and will establish and implement such procedures as may
         be reasonably necessary to continuously determine and assure that any
         failure of the following does not have a Material Adverse Effect: (i)
         all Property of the Issuer and the operations conducted thereon and
         other activities of the Issuer are in compliance with and do not
         violate the requirements of any Environmental Laws, (ii) no oil,
         hazardous substances or solid wastes are disposed of, discharged or
         otherwise released except in compliance with Environmental Laws, (iii)
         no hazardous substance will be released in a quantity equal to or
         exceeding that quantity which requires reporting pursuant to Section
         103 of CERCLA, and (iv) no oil, oil and gas exploration and production
         wastes or hazardous substance is discharged or released so as to pose
         an imminent and substantial endangerment to public health or welfare or
         the environment which will result in damages recoverable under the OPA.

                  (b) The Issuer will promptly notify the Trustee and the
         registered Note Holders in writing of any threatened action,
         investigation or inquiry by any Governmental Authority of which the
         Issuer has knowledge in connection with any Environmental Laws,
         excluding routine testing and corrective action.

         7.5 Further Assurances. The Issuer will cure promptly any defects in
the creation and issuance of the Notes and the execution and delivery of the
Credit Documents and this Indenture. The Issuer at its expense will promptly
execute and deliver to the Trustee upon request all such other documents,
agreements and instruments to comply with or accomplish the covenants and
agreements of the Issuer in the Credit Documents and this Indenture, or to
further evidence and more fully describe the Collateral intended as security for
the Notes, or to correct any omissions in the Credit Documents, or to state more
fully the security obligations set out herein or in any of the Credit Documents,
or to perfect, protect or preserve any Liens created pursuant to any of the
Credit Documents, or to make any recordings, to file any notices or obtain any
consents, all as may be necessary or appropriate in connection therewith. To
facilitate assembling the Collateral upon the occurrence of an Indenture Event
of Default and making it available to the Indenture Trustee at a place to be
designated by the Indenture Trustee which is reasonably convenient, the Issuer
has agreed to, among other things, move the Drilling Rig under certain
conditions as specified in Section 3.3(c) of the First Naval Mortgage. In
addition and in connection therewith, the Issuer acknowledges that the Indenture
Trustee and the Note Holders have certain rights under and pursuant to the
Operating Services Agreement which rights shall be exercisable under the
circumstances and in

                                      -46-


<PAGE>   52



accordance with the terms of the Operating Services Agreement without any demand
on, or legal or other proceeding or action against, the Issuer.

         7.6 Performance of Obligations. The Issuer will pay the Notes according
to the reading, tenor and effect thereof; and the Issuer will perform every act
and discharge all of the obligations to be performed and discharged by it under
the Credit Documents including, without limitation, this Indenture, at the time
or times and in the manner specified.

         7.7 ERISA Information and Compliance. The Issuer will furnish to the
Trustee and the Note Holders (i) immediately upon becoming aware of the
occurrence of any ERISA Event or of any "prohibited transaction," as described
in section 406 of ERISA or in section 4975 of the Code, in connection with any
Plan or any trust created thereunder, a written notice signed by a Responsible
Officer specifying the nature thereof, what action the Issuer or the ERISA
Affiliate is taking or proposes to take with respect thereto, and, when known,
any action taken or proposed by the Internal Revenue Service, the Department of
Labor or the PBGC with respect thereto, and (ii) immediately upon receipt
thereof, copies of any notice of the PBGC's intention to terminate or to have a
trustee appointed to administer any Plan. With respect to each Plan (other than
a Multiemployer Plan), the Issuer will, and will cause each ERISA Affiliate to,
(i) satisfy in full and in a timely manner without giving rise to any Lien, all
of the contribution and funding requirements of section 412 of the Code
(determined without regard to subsections (d), (e), (f) and (k) thereof) and of
section 302 of ERISA (determined without regard to sections 303, 304 and 306 of
ERISA), and (ii) pay, or cause to be paid, to the PBGC in a timely manner, all
premiums required pursuant to sections 4006 and 4007 of ERISA.

         7.8 Debt Service Reserve Fund. The Trustee shall establish an account
styled "Noble/Paul Romano Debt Service Reserve Fund" (the "Debt Service Reserve
Fund"), subject to the Trustee's sole dominion and control. From the proceeds
received by the Issuer, upon the issuance of the Notes pursuant hereto and
pursuant to the Note Purchase Agreements, Issuer shall deposit or cause to be
deposited an amount in the Debt Service Reserve Fund equal to two (2) months
worth of prepayments required on the Notes pursuant to Section 3.4(a) and (b).
Five (5) Business Days prior to a Payment Date, the Trustee shall determine
whether the sums received in the Collection Account pursuant to Section 4.1, 4.2
or 4.3 since the last preceding Payment Date together with the Working Capital
Reserve Fund provided pursuant to Section 7.15 below will be sufficient to cover
the required payments of principal and interest due on the Notes under Article 3
hereof on the next Payment Date. In the event the Trustee determines that
insufficient funds are available as aforesaid, the Trustee will give notice to
the Issuer and each Note Holder three (3) Business Days prior to the Payment
Date that a shortfall (a "Shortfall") exists, the amount thereof, the basis for
such Shortfall and the Trustee's intention to draw on the Debt Service Reserve
Fund to cover such Shortfall. In such event, the Trustee will transfer an amount
equal to the lesser of (i) the Shortfall and (ii) the balance in the Debt
Service Reserve Fund to the Collection Account on the Business Day next
preceding the Payment Date. Thereafter, from time to time, any Shortfall in the
Debt Service Reserve Fund shall be replenished as provided in Section 4.1.

         In the event (A) the Parent executes and delivers the Capital Funding
Agreement together with an opinion of counsel for the Parent in form and
substance reasonably satisfactory to the Trustee as to the authorization and
enforceability of the Capital Funding Agreement upon the Parent, (B) no

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<PAGE>   53



Indenture Default or Indenture Event of Default exists and is continuing
hereunder and (C) the then outstanding senior unsecured debt securities of Noble
Corp. are rated Investment Grade, the Trustee shall distribute to the Issuer,
upon the Issuer's request, all sums then held in the Debt Service Reserve Fund
and such account shall be closed but if such debt securities of Noble Corp. at
any time thereafter are not rated Investment Grade or are not rated then Issuer
and Parent shall immediately re-open and fund the Debt Service Reserve Fund and
or provide comparable security (as in a letter of credit) to the satisfaction of
the Majority Holders.

         7.9 Maintenance of Agency. So long as any of the Notes remain
Outstanding, the Issuer will maintain a single agency where: (i) the Notes may
be presented for payment, and (ii) the Notes may be presented for registration
of transfer, exchange or replacement as in Article 2 provided. The Issuer hereby
designates the principal corporate trust office of the Trustee in Houston,
Texas, as its agency for each such purpose. The Issuer will give to the Trustees
and the holders of the Notes prior written notice of any change of location of
any such agency, which shall be located in the United States. In case the Issuer
shall fail to maintain such agency or shall fail to give such notices of any
change of the location thereof, presentations and demands may be made and notice
may be served at the address specified for the Issuer in or pursuant to Section
12.3. Notice and demands to or upon the Issuer in respect to the Notes or this
Indenture may also be served at such address.

         7.10 Additional Assurances. The Issuer will cause this Indenture, any
and all supplemental indentures, mortgages, security agreements, instruments of
further assignment, financing statements and continuation statements at all
times to be kept recorded and filed in such manner and in such places as may be
required by law to fully preserve and protect the rights of the holders of the
obligations secured hereby as a first priority security interest and the
Trustees hereunder and under all other documents and instruments evidencing or
securing the obligations secured hereby (including, without limitation,
documents and instruments granting Liens to the Trustees with respect to the
Trust Estate). The Issuer will, at its expense and at any time and from time to
time, promptly execute and deliver all further instruments and documents and
take all further action that may be necessary or desirable or that the Trustee
may request in order to (a) perfect and protect the Liens and other rights
created or purported to be created hereby and by the other Credit Documents and
the first priority of such Liens and other rights; (b) enable the Trustee to
exercise and enforce its rights and remedies hereunder in respect of the
Collateral; or (c) otherwise effect the purposes of this Indenture, including,
without limitation: (i) executing and filing such supplements to this Indenture
and such financing or continuation statements (or amendments thereto) as may be
necessary or desirable or that the Trustee may reasonably request in order to
perfect and preserve the Liens created or purported to be created hereby or
thereby; and (ii) furnishing to the Trustee from time to time such other
information in connection with the Collateral as the Trustee may reasonably
request, all in reasonable detail. The Issuer will furnish to the Trustee any
information which the Trustee may from time to time reasonably request
concerning any covenant, provision or representation contained herein or
concerning any other matter in connection with the Collateral.

         7.11 Year 2000 Compliance. The Issuer shall take appropriate steps to
assess, quantify, address and resolve its business and financial risks resulting
from the Year 2000 Problem, including those business and economic risks
resulting from the failure of key suppliers, vendors and customers of the Issuer
to properly assess, quantify, address and resolve the Year 2000 Problem.


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<PAGE>   54



         7.12 Change in Location of Collateral or Issuer. The Drilling Rig shall
be kept at all times in United States territorial waters in the Gulf of Mexico
or in the Gulf of Mexico on or above the outer Continental Shelf of the United
States and as set forth in Section 1 of the Drilling Order. Issuer will not,
without the Required Holders' prior written consent, change the location of any
of the other Collateral to any state, county or other jurisdiction in which
Trustee has not already filed a financing statement or taken other necessary
steps to perfect its first priority security interests in the Collateral or to
maintain such perfection. Issuer will give Trustee and each Note Holder thirty
(30) days' prior written notice of (i) the opening or closing of any place of
Issuer's business or (ii) any change in the location of Issuer's chief executive
office or address.

         7.13 Change in Issuer's Name. Issuer will not change its name or
identity without notifying Trustee of such change in writing at least thirty
(30) days prior to the effective date of such change. Without the express
written consent of the Majority Holders, however, Issuer will not engage in any
other business or transaction under any name other than Issuer's name hereunder.

         7.14 Corporate Independence. Until 367 days have elapsed following
payment and satisfaction of all Notes, the Issuer shall not change its legal
structure to anything other than a corporation and shall observe the applicable
legal requirements for the recognition of the Issuer as a legal entity separate
and apart from Parent and its Affiliates, including, without limitation,
compliance with the following:

                  (i) the Issuer shall maintain separate corporate records,
         books of account and financial statements (each of which shall be
         sufficiently full and complete to permit a determination of the
         Issuer's assets and liabilities and to permit a determination of the
         obligees thereon and the time for performance on each of the Issuer's
         obligations) from those of the Parent and its Affiliates;

                  (ii) the Issuer shall not commingle any of its assets or funds
         with those of the Parent or any of its Affiliates;

                  (iii) the board of directors of the Issuer shall be elected
         independently from the board of directors of the Parent and any of its
         Affiliates and shall at all times include at least one Independent
         Director (except in the case of death, incapacity, resignation or
         removal, and in any such case said Independent Director shall be
         promptly replaced);

                  (iv) the board of directors and stockholders of the Issuer
         shall hold all regular and special meetings appropriate to authorize
         corporate actions. Regular meetings of directors will be held at least
         annually. The board of directors may act from time to time through one
         or more committees of the board in accordance with the Issuer's
         by-laws. Appropriate minutes of all meetings of board of directors (and
         committees thereof) and of the stockholders' meetings shall be kept by
         the Issuer;

                  (v) the Issuer shall act solely in its own corporate name and
         through its own authorized officers and agents. Neither the Parent nor
         any of its Affiliates shall be appointed agent of the Issuer;


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<PAGE>   55



                  (vi) the Issuer will maintain a separate office which shall be
         physically separate from space occupied by the Parent, or any of its
         Affiliates (but may be separate space occupied solely by the Issuer at
         the offices of the Parent or any of its Affiliates) and shall be
         identified as the Issuer's office so it can be identified by outsiders;

                  (vii) the Issuer shall at all times hold itself out to the
         public under the Issuer's own name as a legal entity separate and
         distinct from Parent and its Affiliates (the foregoing to include, but
         not be limited to, use of materially separate and distinct letterhead
         and telephone number(s));

                  (viii) all financial reports prepared by the Issuer shall
         comply with GAAP and shall be issued separately from any reports
         prepared for Parent and any of its Affiliates; and

                  (ix) Parent's financial reports shall disclose the
         separateness of the Issuer as required by GAAP and that the Collateral
         is owned by the Issuer and is not available to creditors of Parent or
         any of its Affiliates.

         7.15 Working Capital Fund. The Trustee shall establish an account
styled "Noble/Paul Romano Working Capital Fund" (the "Working Capital Fund"),
subject to the Trustee's sole dominion and control. From the proceeds received
by the Issuer, upon the issuance of the Notes pursuant hereto and pursuant to
the Note Purchase Agreements, Issuer shall deposit or cause to be deposited an
amount in the Working Capital Fund equal to $1,950,000. Five (5) Business Days
prior to the first two Payment Dates, the Trustee shall determine whether the
sums in the Collection Account will be sufficient to cover the required payments
of principal and interest due on the Notes under Article 3 hereof on the next
Payment Date. In the event the Trustee determines that insufficient funds are
available as aforesaid, the Trustee will draw on the Working Capital Fund. In
such event, the Trustee will transfer an amount equal to the lesser of (i) the
amount necessary to pay the principal and interest due on the Notes under
Article 3 and (ii) the balance in the Working Capital Fund to the Collection
Account on the Business Day next preceding the Payment Date. Following the
second Payment Date, if the funds in the Collection Account are otherwise
sufficient to pay the amounts required under Article 3, and no Indenture Default
or Indenture Event of Default shall have occurred and be continuing, the Trustee
shall release any funds remaining in the Working Capital Fund to the Collection
Account.

ARTICLE 8.        NEGATIVE COVENANTS.

         The Issuer covenants and agrees that, so long as any of the commitments
under the Note Purchase Agreements are in effect and until payment in full of
Notes issued hereunder, all interest thereon and all other amounts payable by
the Issuer hereunder, without the prior written consent of the Majority Holders
(except for Sections 8.12, 8.13, 8.17 and 8.18 which shall require the prior
written consent of the Required Holders):

         8.1 Debt. The Issuer will not incur, create, assume, suffer to exist or
otherwise become liable in respect of any Debt, except:

                  (a) the Notes or other indebtedness arising under the Credit
         Documents;

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<PAGE>   56



                  (b) accounts payable (for the deferred purchase price of
         Property or services) from time to time incurred in the ordinary course
         of business which, if greater than 60 days past the invoice or billing
         date, are being Contested In Good Faith; and

                  (c) Debt owing to the Parent evidenced by subordinated
         promissory notes in the form attached hereto as Annex C.

         8.2 Liens. The Issuer will not create, incur, assume or permit to exist
any Lien on any of its Properties (now owned or hereafter acquired), or upon any
income or profits therefrom except:

                  (a) Liens securing the payment of the Notes; and

                  (b) during the period up to but not including the Maturity
         Date, Excepted Liens.

         8.3 Investments, Loans and Advances. The Issuer will not make or permit
to remain outstanding any loans or advances to or investments in any Person,
except that the foregoing restriction shall not apply to:

                  (a) accounts receivable arising in the ordinary course of
         business; and

                  (b) Permitted Investments made pursuant to the requirements of
         this Indenture.

         8.4 Dividends, Distributions and Redemptions. In the event of the
occurrence and during the continuance of an Indenture Default or Indenture Event
of Default, the Issuer will not declare or pay any dividend, purchase, redeem or
otherwise acquire for value any of its stock now or hereafter outstanding,
return any capital to its stockholders or make any distribution of its assets to
its stockholders.

         8.5 Sales and Leasebacks. The Issuer will not enter into any
arrangement, directly or indirectly, with any Person whereby the Issuer shall
sell or transfer any of its Property, whether now owned or hereafter acquired,
and whereby the Issuer shall then or thereafter rent or lease as lessee such
Property or any part thereof or other Property which the Issuer intends to use
for substantially the same purpose or purposes as the Property sold or
transferred.

         8.6 Nature of Business. The Issuer will not engage directly or
indirectly in any business or activity except owning and operating the Drilling
Rig and activities incidental thereto.

         8.7 Limitation on Leases. The Issuer will not create, incur, assume or
suffer to exist any obligation for the payment of rent or hire of Property of
any kind whatsoever (real or personal including capital leases), under leases or
lease agreements which would cause the aggregate amount of all payments made by
the Issuer pursuant to all such leases or lease agreements to exceed $500,000 in
any period of twelve consecutive calendar months during the life of such leases.

         8.8 Mergers, Etc. The Issuer will not merge into or with or consolidate
with any other Person, or sell, lease or otherwise dispose of (whether in one
transaction or in a series of transac tions) all or substantially all of its
Property to any other Person.

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<PAGE>   57



         8.9 Proceeds of Notes. The Issuer will not permit the proceeds of the
Notes to be used for any purpose other than those permitted by the Note Purchase
Agreements. Neither the Issuer nor any Person acting on behalf of the Issuer has
taken or will take any action which might cause any of the Credit Documents to
violate Regulation T, U or X or any other regulation of the Board of Governors
of the Federal Reserve System or to violate Section 7 of the Securities Exchange
Act of 1934 or any rule or regulation thereunder, in each case as now in effect
or as the same may hereinafter be in effect.

         8.10 ERISA Compliance. The Issuer will not at any time:

                  (a) engage in, or permit any ERISA Affiliate to engage in, any
         transaction in connection with which the Issuer or any ERISA Affiliate
         could be subjected to either a civil penalty assessed pursuant to
         section 502(c), (i) or (l) of ERISA or a tax imposed by Chapter 43 of
         Subtitle D of the Code that is Material;

                  (b) terminate, or permit any ERISA Affiliate to terminate, any
         Plan in a manner, or take any other action with respect to any Plan,
         which could result in any liability of the Issuer or any ERISA
         Affiliate to the PBGC that is Material;

                  (c) fail to make, or permit any ERISA Affiliate to fail to
         make, full payment when due of all amounts which, under the provisions
         of any Plan, agreement relating thereto or applicable law, the Issuer
         or any ERISA Affiliate is required to pay as contributions thereto to
         the extent that such failure could reasonably be expected to result in
         a liability of the Issuer or any ERISA Affiliate that is Material;

                  (d) permit to exist, or allow any ERISA Affiliate to permit to
         exist, any accumulated funding deficiency within the meaning of Section
         302 of ERISA or section 412 of the Code, whether or not waived, with
         respect to any Plan;

                  (e) permit, or allow any ERISA Affiliate to permit, the
         actuarial present value of the benefit liabilities under any Plan
         maintained by the Issuer or any ERISA Affiliate which is regulated
         under Title IV of ERISA to exceed the current value of the assets
         (computed on a plan termination basis in accordance with Title IV of
         ERISA) of such Plan allocable to such benefit liabilities by an amount
         which in the event of the termination of such Plan would be Material.
         The term "actuarial present value of the benefit liabilities" shall
         have the meaning specified in section 4041 of ERISA;

                  (f) contribute to or assume an obligation to contribute to, or
         permit any ERISA Affiliate to contribute to or assume an obligation to
         contribute to, any Multiemployer Plan if a future withdrawal or partial
         withdrawal from such Plan could reasonably be expected to result in a
         withdrawal liability assessment which is Material;

                  (g) acquire, or permit any ERISA Affiliate to acquire, an
         interest in any Person that causes such Person to become an ERISA
         Affiliate with respect to the Issuer or any ERISA Affiliate if such
         Person sponsors, maintains or contributes to, or at any time in the
         six-year period preceding such acquisition has sponsored, maintained,
         or contributed to, (1)

                                      -52-


<PAGE>   58



         any Multiemployer Plan, if a Material withdrawal liability has been
         assessed by such Plan against such ERISA Affiliate or Person or if a
         future withdrawal or partial withdrawal from such Plan could reasonably
         be expected to result in a withdrawal liability assessment which is
         Material or (2) any other Plan that is subject to Title IV of ERISA
         under which the actuarial present value of the benefit liabilities
         under such Plan exceeds the current value of the assets (computed on a
         plan termination basis in accordance with Title IV of ERISA) of such
         Plan allocable to such benefit liabilities by an amount which in the
         event of the termination of such Plan would be Material;

                  (h) incur, or permit any ERISA Affiliate to incur, a Material
         liability to or on account of a Plan under sections 515, 4062, 4063,
         4064, 4201 or 4204 of ERISA;

                  (i) contribute to or assume an obligation to contribute to, or
         permit any ERISA Affiliate to contribute to or assume an obligation to
         contribute to, any employee welfare benefit plan, as defined in section
         3(1) of ERISA, including, without limitation, any such plan maintained
         to provide benefits to former employees of such entities, that may not
         be terminated by such entities without any Material liability; or

                  (j) amend or permit any ERISA Affiliate to amend, a Plan
         resulting in an increase in current liability such that the Issuer or
         any ERISA Affiliate is required to provide security to such Plan under
         section 401(a)(29) of the Code.

         8.11 Sale or Discount of Receivables. The Issuer will not discount or
sell (with or without recourse) any of its notes receivable or accounts
receivable.

         8.12 Sale of Drilling Rig. The Issuer will not sell, lease, charter,
assign, convey, dispose or otherwise transfer the Drilling Rig or any interest
therein; provided, however, this covenant shall not apply to attendant equipment
to the Drilling Rig which is obsolete or which is replaced by equipment of equal
or greater value.

         8.13 Environmental Matters. The Issuer will not cause or permit any of
its Property to be in violation of, or do anything or permit anything to be done
which will subject any such Property to any remedial obligations under any
Environmental Laws, assuming disclosure to the applicable Governmental Authority
of all relevant facts, conditions and circumstances, if any, pertaining to such
Property where such violations or remedial obligations would have a Material
Adverse Effect.

         8.14 Transactions with Affiliates. The Issuer will not enter into any
transaction, including, without limitation, any purchase, sale, lease or
exchange of Property or the rendering of any service, with any Affiliate unless
such transactions are otherwise permitted under this Indenture or the other
Credit Documents, are in the ordinary course of its business and are upon fair
and reasonable terms no less favorable to it than it would obtain in a
comparable arm's length transaction with a Person not an Affiliate.

         8.15 Subsidiaries. The Issuer has no subsidiaries and shall not create
or acquire any subsidiaries.


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<PAGE>   59



         8.16 Location of Issuer. The Issuer will not cause or permit any change
to be made in its corporate name or identity or any change to be made in the
address of its chief executive office or principal place of business (presently
being the address set forth in Section 12.3), unless the Issuer shall have first
notified the Trustee and each Note Holder of such change at least thirty (30)
days prior to the effective date of such change and shall have first taken all
action required by the Trustee for the purpose of further perfecting or
protecting the rights of the Trustee in the Collateral. In any notice furnished
pursuant to this subsection 8.16, the Issuer will state that the notice is
required by this Indenture and contains facts that may require additional
filings of financing statements.

         8.17 Acquisition of Notes. The Issuer will not, directly or indirectly
through any of its Affiliates or otherwise, purchase, redeem, prepay or
otherwise acquire any of the Outstanding Notes except upon payment or prepayment
of the Notes in accordance with the terms of this Indenture and the Notes. In
case the Issuer or any of its Affiliates acquires any Notes, such Notes shall
thereupon be delivered to the Trustee for cancellation and no Notes shall be
issued in substitution therefor.

         8.18 Non-Petition Covenant. With respect to the CP Conduit as a
Purchaser, the Issuer hereby agrees that until the 368th day following the
maturity of the last maturing commercial paper note to be issued by the CP
Conduit in connection with its funding of its investment in the Notes, the
Issuer will not institute, and will not join with others in instituting, any
involuntary bankruptcy or analogous proceeding against the CP Conduit under any
bankruptcy, reorganization, receivership or similar law, domestic or foreign, as
now or hereafter in effect.

         8.19 Jurisdiction of Registration. The Issuer shall not change the
jurisdiction of registration of the Drilling Rig to another jurisdiction, unless
the Issuer has given the Trustee and the Note Holders not less than 60 days
prior written notice, the Required Holders have consented (which consent shall
not be unreasonably withheld) and the Issuer has furnished the Trustee and the
Note Holders with a new replacement ship mortgage acceptable to the Trustee and
the Required Holders and appropriate opinions of counsel, acceptable in form and
substance to the Required Holders, with respect to such mortgage and the filing
and first priority thereof.

ARTICLE 9.        THE TRUSTEES.

         9.1 Certain Duties and Responsibilities of Trustees.

                  (a) Except during the continuance of an Indenture Event of
         Default:

                           (i) each Trustee undertakes to perform such duties
                  and only such duties as are specifically set forth in this
                  Indenture, and no implied covenants or obligations shall be
                  read into this Indenture against such Trustee; and

                           (ii) each Trustee may conclusively rely, in good
                  faith, as to the truth of the statements and the correctness
                  of the opinions expressed therein, upon certificates or
                  opinions furnished to such Trustee and conforming to the
                  requirements of this Indenture or other Credit Documents; but
                  in the case of any such certificates or opinions which by any
                  provision hereof are specifically required to be furnished to

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<PAGE>   60



                  such Trustee, such Trustee shall be under a duty to examine
                  the same to determine whether or not they conform to the
                  requirements of this Indenture.

                  (b) In case an Indenture Event of Default has occurred and is
         continuing, each Trustee shall exercise such of the rights and powers
         vested in it by this Indenture for the benefit of the holders of the
         Notes, and use the same degree of care and skill in their exercise, as
         a prudent man would exercise or use under the circumstances in the
         conduct of his own affairs.

                  (c) No provision of this Indenture shall be construed to
         relieve any Trustee from liability for its own negligence or its own
         willful misconduct, or the inaccuracy of any of its representations or
         warranties made in Section 9.14, except that:

                           (i) no Trustee which is a corporation or banking
                  association shall be liable for any error of judgment made in
                  good faith by an officer of such Trustee unless it shall be
                  proved that such Trustee was negligent in ascertaining
                  material facts; and

                           (ii) no Trustee shall be liable to the holder of any
                  Note with respect to any action taken or omitted to be taken
                  by it, in good faith after an Indenture Event of Default shall
                  have occurred in accordance with the direction of the Majority
                  Holders relating to the method and place of conducting any
                  proceeding for any remedy available to such Trustee.

                  (d) No provision of this Indenture shall require any Trustee
         to expend or risk its own funds or otherwise incur any financial
         liability in the performance of any of its duties hereunder or in the
         exercise of any of its rights or powers, if it shall have reasonable
         grounds for believing that repayment of such funds or adequate
         indemnity against such risk or liability is not reasonably assured to
         it.

                  (e) Whether or not therein expressly so provided, every
         provision of this Indenture relating to the conduct or affecting the
         liability of or affording protection to any Trustee shall be subject to
         the provisions of this Section 9.1.

                  (f) The Trustee shall give to the holder of each Note written
         notice of each and every Indenture Default or Indenture Event of
         Default of which one of its Responsible Officers has actual knowledge
         within three (3) days of obtaining such actual knowledge unless the
         same shall be cured during such period.

         9.2 Trustees' Compensation and Indemnification. The Issuer covenants
and agrees to pay to each Trustee promptly (and in any event within 30 days
after receipt of any invoice or other statement or notice) and each Trustee
shall be entitled to the fees and expenses determined as provided in Schedule
9.2 hereto for all services rendered and expenses incurred by it in the
execution of the trusts hereby created and in the exercise and performance of
any of the powers and duties hereunder of such Trustee, which compensation shall
not be limited by any provisions of law in regard to the compensation of a
trustee of an express trust, and the Issuer will pay or reimburse each

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<PAGE>   61



Trustee promptly (and in any event within 30 days after receipt of any invoice
or other statement or notice) for all reasonable expenses, disbursements and
advances incurred or made by such Trustee in accordance with any of the
provisions of this Indenture (including the reasonable compensation and the
expenses and disbursements of its external counsel and of all Persons not
regularly in its employ) except any such expense, disbursement or advance as may
arise from its gross negligence (but not mere negligence) or bad faith or wilful
misconduct. Subject to Section 9.3(f), each Trustee agrees that it shall have no
right against any holder of any Note for the payment of compensation for its
services hereunder or any expenses or disbursements incurred in connection with
the exercise and performance of its powers and duties hereunder or any
indemnification against liability which it may incur in the exercise and
performance of such powers and duties but on the contrary, shall look solely to
the Issuer for such payment and indemnification and that it shall have no Lien
on or security interest in the Collateral as security for such compensation,
expenses, disbursements and indemnification except to the extent provided for in
Section 4.3.

         9.3 Certain Rights of Trustees.

                  (a) No Trustee shall be responsible for any recitals herein or
         for insuring all or any portion of the Trust Estate nor shall any
         Trustee be bound to ascertain or inquire as to the performance or
         observance of any covenants, conditions or agreement contained herein.
         Except in the case of an Indenture Default or Indenture Event of
         Default of which a Responsible Officer of the Trustee has actual
         knowledge, the Trustee shall be deemed to have knowledge of an
         Indenture Default or Indenture Event of Default only upon receipt of
         written notice thereof from the Issuer or any holder of a Note;
         provided, however, that the Trustee shall be deemed to have actual
         knowledge of (i) any failure to receive payments under the Shell
         Contract when due, if the Trustee shall have received a copy of the
         billing for such payment pursuant to Section 7.3(e) above, (ii) sums
         required to be deposited in the Debt Service Reserve Fund and sums
         actually deposited, and (iii) of the principal of, any applicable
         Make-Whole Amount or interest on, any Note on the date any such payment
         is due.

                  (b) No Trustee makes any representation, or warranty as to the
         validity, sufficiency or enforceability of this Indenture, the Notes,
         the Note Purchase Agreements or any other Credit Documents, or as to
         the title, operation, merchantability or fitness for use or purpose,
         value, compliance with specifications, condition, design, quantity,
         durability or otherwise with respect to the Drilling Rig or any other
         Collateral or any substitute therefor. No Trustee shall be accountable
         to anyone for the use or application of any of the Notes of the
         proceeds thereof or for the use or application of any Collateral or the
         proceeds thereof which shall be released from the Lien and security
         interest in favor of such Trustee held in trust under the terms hereof,
         in accordance with the provisions of this Indenture.

                  (c) Each Trustee may rely and shall be protected in acting or
         refraining from acting upon any resolution, certificate, statement,
         instrument, opinion, report, notice request, direction, consent, order,
         bond, note or other paper or document believed by it, in good faith, to
         be genuine and to have been signed or presented by the proper party or
         parties.


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<PAGE>   62



                  (d) Any request, direction or authorization by the Issuer
         shall be sufficiently evidenced by a request, direction or
         authorization in writing, delivered to a Trustee, and signed in the
         name of such party by a Responsible Officer; and any resolution of the
         Board of Directors of the Issuer or any committee thereof shall be
         sufficiently evidenced by a copy of such resolution certified by its
         Secretary or an Assistant Secretary to have been duly adopted and to be
         in full force and effect on the date of such certification, and
         delivered to such Trustee.

                  (e) Any Trustee may consult with counsel, appraisers,
         engineers, accountants and other skilled persons to be selected by such
         Trustee, and the written advice of any thereof shall be full and
         complete authorization and protection in respect of any action taken,
         suffered or omitted by it hereunder in good faith and in reliance
         thereon.

                  (f) No Trustee shall be under any obligation to take any
         action to protect, preserve or enforce any rights or interests in the
         Collateral or to take any action towards the execution or enforcement
         of the trusts hereunder or otherwise hereunder, whether on its own
         motion or on the request of any other Person, if it shall have notified
         the holders of the Notes that the same, in the opinion of such Trustee,
         may involve pecuniary loss, liability or expense, unless the Issuer or
         one or more holders of the Notes shall offer and furnish reasonable
         security or indemnity reasonably satisfactory to such Trustee against
         pecuniary loss, liability and expense to such Trustee. With respect to
         any original Purchasers of the Notes or any other Institutional
         Investor an indemnity agreement by such Purchaser, in form and
         substance reasonably satisfactory to such Trustee, will satisfy such
         requirement without any bond, security or third party indemnity.

                  (g) No Trustee shall be bound to make any investigation into
         the facts or matters stated in any resolution, certificate, statement,
         instrument, opinion, report, notice, request, direction, consent,
         order, bond, note or other paper or document, unless requested in
         writing to do so by the Majority Holders and such holders shall have
         tendered funds to pay expenses to be incurred in performing such
         duties.

                  (h) Any Trustee may execute any of the trusts or powers
         hereunder or perform any duties hereunder either directly or by or
         through agents or attorneys and such Trustee shall not be responsible
         for any misconduct or negligence on the part of any agent or attorney
         appointed by it with due care.

                  (i) The provisions of paragraphs (c) through (h), inclusive,
         of this Section 9.3, shall be subject to the provisions of Section 9.1.

                  (j) No Trustee need post any bond for any action taken under
         this Indenture.

         9.4 Showings Deemed Necessary by a Trustee. Anything else in this
Indenture contained to the contrary notwithstanding, each Trustee shall have the
right, but shall not be required, to demand in respect of the withdrawal of any
cash (other than payments out of the Collection Account or the Debt Service
Reserve Fund or the Working Capital Fund), the release of any Property or the
subjection of any after acquired Property to any Lien to be held by such Trustee
pursuant to the terms

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<PAGE>   63



hereof, or any other action whatsoever within the purview hereof, any showings,
certificates, opinions, appraisals or other information which such Trustee may
deem reasonably necessary or appropriate in addition to the matters required by
the terms hereof as a condition precedent to such action.

         9.5 Status of Monies Received. All monies received by a Trustee shall,
until used or applied as herein provided, be held in trust for the purposes for
which they were received, but, if such Trustee is a bank, need not be segregated
in any manner from any other monies, except to the extent required by law, and
may be deposited by such Trustee under such general conditions as may be (if
such Trustee is a bank) prescribed by law and such Trustee's trust department,
and such Trustee shall be under no liability for interest on any monies received
by it hereunder except as provided in Section 4.4. Any Trustee which is a trust
company, banking corporation or banking association and any affiliated
corporation may be interested in any financial transaction with the Issuer or
any of its Affiliates; and any such Trustee may act as depository or otherwise
in respect to other Securities of the Issuer or any of its Affiliates, all with
the same rights which it would have if not a Trustee; provided that such Trustee
shall not exercise any right of setoff against any part of the Trust Estate.

         9.6 Resignation of Trustees. Any Trustee may resign and be discharged
of the trusts hereby created by mailing notice to the Issuer and to all holders
of Notes specifying the time and date (not earlier than sixty (60) days after
the date of such notice) when such resignation shall take effect. Such
resignation shall take effect upon the appointment, qualification and acceptance
of a successor trustee as herein provided.

         9.7 Removal of Trustees. Any Trustee may be removed, with or without
cause, and a successor Trustee may be appointed at any time by the Majority
Holders and delivered to each other Trustee and the Issuer, and, in the case of
the appointment of a successor Trustee, to such successor Trustee.

         9.8 Successor Trustee. Each Trustee appointed in succession of the
Trustee named in this Indenture, or its successor in trust, shall be a trust
company, banking corporation or banking association organized under the laws of
the United States of America, in good standing and having a capital and
unimpaired surplus aggregating at least $500,000,000, if there be such a trust
company, banking corporation or banking association qualified, able and willing
to accept the trusts upon reasonable or customary terms; and otherwise having
the highest capital of such trust companies, banking corporations or banking
associations that are qualified, able and willing to accept the trusts upon
reasonable or customary terms.

         9.9 Appointment of Successor Trustees. If a Trustee shall have given
notice of resignation pursuant to Section 9.6 or if notice of removal shall have
been given to a Trustee and the Issuer pursuant to Section 9.7 and such notice
does not appoint a successor Trustee or if such notice of removal appointed a
successor Trustee and such successor shall not have accepted such appointment
within fifteen (15) days after the giving of such notice of removal, a successor
Trustee may be appointed by the Majority Holders with the consent of the Issuer
not to be unreasonably withheld. If no such appointment shall have been made
within twenty-five (25) days after the giving of such notice of resignation or
the giving of such notice of removal, a successor Trustee may be

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<PAGE>   64



appointed by the holder of any Outstanding Note or, upon application of the
retiring Trustee, by any court of competent jurisdiction.

         9.10 Merger or Consolidation of Trustee. Any corporation into which a
Trustee which is a corporation, or any successor to it in the trusts created by
this Indenture, may be merged or consolidated or with which it or any successor
to it may be consolidated or any corporation resulting from any merger or
consolidation to which such Trustee or any successor to it shall be a party or
any state or national bank or trust company succeeding to the corporate trust
business of the Trustee as a whole or substantially as a whole (provided such
corporation which is a successor to the Trustee shall be a corporation organized
under the laws of any state of the United States of America or of the United
States of America, having a capital and surplus of at least $500,000,000 and
such corporation which is a successor to any other Trustee shall be permitted by
law to perform its obligations hereunder), shall be the successor to such
Trustee under this Indenture without the execution or filing of any paper or any
further act on the part of any of the parties hereto. The Issuer covenants that
in case of any such merger, consolidation or transfer of the corporate trust
business it will, upon the request of the merged, consolidated or transferred
corporation, execute, acknowledge and cause to be recorded or filed suitable
instruments in writing to confirm the estates, rights and interests of such
corporation as such Trustee under this Indenture.

         9.11 Acceptance of Appointment by Successor Trustee. Any new Trustee
appointed pursuant to any of the provisions hereof shall execute, acknowledge
and deliver to the Issuer an instrument accepting such appointment; and
thereupon such new Trustee, without any further act, deed or conveyance, shall
become vested with all the estates, Properties, rights, powers and trusts of its
predecessor in the rights hereunder with like effect as if originally named as
Trustee herein; but, nevertheless upon the Written Request of the Issuer or the
successor Trustee, the Trustee ceasing to act, upon payment of fees and expenses
due to it, shall execute and deliver an instrument transferring to such
successor Trustee, upon the trusts herein expressed, all the estates,
Properties, rights, powers, and trusts of the Trustee so ceasing to act, and
shall duly assign, transfer and deliver any of the Property of the Trust Estate
and monies held by such Trustee to the successor Trustee so appointed in its or
his place. Upon acceptance of appointment by a successor Trustee as provided in
this Section 9.11, the successor Trustee shall give to the Note Holders written
notice of the succession of such Trustee to the trusts hereunder. Neither
failure so to mail nor any defect in the notice so mailed shall affect the
sufficiency of the proceedings in question.

         9.12 Conveyance upon Request of Successor Trustee. Should any deed,
conveyance or instrument in writing from the Issuer be required by any successor
Trustee for more fully and certainly vesting in and confirming to such new
Trustee such estates, Properties, rights, powers and trusts, then upon request
of such successor Trustee any and all such deeds, conveyances and instruments in
writing shall be made, executed, acknowledged and delivered, and, if and where
appropriate, shall be caused to be recorded and filed, by the Issuer.

         9.13 Co-Trustees and Additional Trustees.

                  (a) Delivery of Documents. Anything herein contained to the
         contrary notwithstanding, if, at any time or times, in order to conform
         with any law of any jurisdiction in which the Issuer shall then own or
         hold any Collateral, the Trustee shall be advised by

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<PAGE>   65



         counsel satisfactory to it that it is necessary or prudent in the
         interest of the holders of the Notes so to do, the Trustee shall
         execute and deliver any and all instruments and agreements necessary or
         proper to appoint, on behalf of the Trustee, the Note Holders and the
         Issuer, another trust company, banking corporation or banking
         association, or one or more other Persons approved by the Trustee
         either to act as co-trustee or co-trustees hereunder, jointly with the
         Trustee, or its successors, or to act as separate trustee or trustees
         hereunder; and the trust company, banking corporation or banking
         association, or the Person or Persons so appointed shall be such
         co-trustee or co-trustees, or separate trustee or trustees, with such
         powers, duties and discretion as shall be specified in the said
         instruments or agreements of appointment, executed as aforesaid. It
         shall not be necessary for any holder of a Note or the Issuer or any
         other Person other than the Trustee to execute and deliver any such
         instruments or agreements.

                  (b) Exercise of Powers. The rights, powers, duties and
         obligations conferred or imposed upon the Trustee shall be conferred
         and imposed upon, and exercised or performed by the Trustee, or jointly
         by the Trustee and any co-trustee or co-trustees or separate trustee or
         trustees appointed pursuant to this Section 9.13 as provided herein or
         in the instrument or agreement appointing such co-trustee or
         co-trustees or separate trustee or trustees, except to the extent that
         under the law of any jurisdiction in which any particular act or acts
         are to be performed the Trustee shall be incompetent or unqualified to
         perform such act or acts, in which event such rights, powers, duties
         and obligations shall be exercised and performed by such co-trustee or
         co-trustees or separate trustee or trustees.

                  (c) Trustee Attorney-in-Fact. Any co-trustee or co-trustees or
         separate trustee or trustees appointed hereunder may at any time by an
         instrument in writing, and each Trustee by this Indenture does hereby,
         constitute the Trustee, or its successor in the trusts hereunder, his,
         their or its agent or attorney-in-fact, with full power and authority,
         to the extent which may be permitted by law, to do any and all acts and
         things and exercise any and all discretion authorized or permitted by
         him, them or it, for and on behalf of him, them or it, and in his,
         their or its name.

                  (d) Resignation of Co-Trustee or Separate Trustee. Each
         co-trustee or separate trustee appointed pursuant to the provisions of
         this Section 9.13 may resign and may be removed by the Trustee, and the
         successors to such trustees may be appointed by the Trustee as set
         forth in the first paragraph of this Section 9.13.

         9.14 Trustee's Representations and Warranties. The Trustee represents,
warrants and covenants that:

                  (a) Organization, Etc. It is a national banking association
         duly chartered, validly existing and in good standing under the laws of
         the United States of America, and has all requisite power, authority
         and legal right under the laws of the State of Texas and the United
         States to execute, deliver and carry out the terms of each of the
         Credit Documents to which it is a party. Its principal place of
         business is located at its street address set forth in Section 12.3.


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<PAGE>   66



                  (b) Authorization, Etc. It has duly authorized, executed and
         delivered this Indenture and the other Credit Documents to which it is
         a party and this Indenture and the other Credit Documents constitute
         legal, valid and binding obligations, enforceable against it in
         accordance with the terms thereof.

                  (c) No Violation. The execution and delivery of, and
         performance of its obligations under, this Indenture and the other
         Credit Documents to which it is a party will not result in any
         violation of, or be in conflict with, or constitute a default under,
         any of the provisions of its articles of association or by-laws, or of
         any indenture, mortgage, chattel mortgage, deed of trust, conditional
         sales contract, lease, note or bond purchase agreement, license or bank
         loan or credit agreement or other agreement to which it is a party or
         by which it is bound, or any law, judgment, governmental rule,
         regulation or order of any government or governmental authority or
         agency governing the banking or trust powers of the Trustee.

                  (d) No Consents or Approvals. Neither the execution and
         delivery by it, in its individual capacity or as Trustee, as the case
         may be, of this Indenture nor the consummation of any of the
         transactions contemplated thereby requires the consent or approval of,
         the giving of notice to, or the registration with, any federal or State
         governmental authority or agency pursuant to any federal or State law
         governing the banking or trust powers of Trustee.

                  (e) Capitalization. It has unimpaired capital and surplus
         aggregating at least $500,000,000.

         9.15 Non-Petition Covenant. With respect to the CP Conduit as a
Purchaser, the Trustee hereby agrees that until the 368th day following the
maturity of the last maturing commercial paper note to be issued by the CP
Conduit in connection with its funding of its investment in the Notes, the
Trustee will not institute, and will not join with others in instituting, any
involuntary bankruptcy or analogous proceeding against the CP Conduit under any
bankruptcy, reorganization, receivership or similar law, domestic or foreign, as
now or hereafter in effect.

ARTICLE 10.       SUPPLEMENTAL INDENTURES, WAIVERS.

         10.1 Supplemental Indentures Without Note Holders' Consent. The Issuer
and the Trustee from time to time and at any time, subject to the restrictions
in this Indenture contained, may, without consent from the holder of any Note,
enter into an indenture or indentures supplemental hereto and which thereafter
shall form a part hereof for any one or more or all of the following purposes:

                  (a) to add to the Trust Estate held by the Trustees pursuant
         to the terms hereof additional Property hereafter acquired by the
         Issuer and intended to be subjected to this Indenture, and to correct
         and amplify the description of any Property subject to this Indenture;

                  (b) to cure any ambiguity or cure, correct or supplement any
         defective provisions of this Indenture or any supplement hereto;
         provided, that the same shall in no respect be adverse to the interests
         of the holders of the Series A Notes or the Series B Notes; and

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<PAGE>   67



                  (c) to appoint a co-trustee or co-trustees, or a separate
         trustee or trustees, pursuant to Section 9.13.

and the Issuer covenants to perform all requirements of any such supplemental
indenture. No restrictions or obligations imposed upon the Issuer may, except as
otherwise proved in this Indenture, be waived or modified by such supplemental
indentures or otherwise.

         10.2 Waivers and Consents by Note Holders; Supplemental Indentures with
Consent.

         (a) Subject to the provisions of the following subsection 10.2(b), upon
the waiver or consent of the Majority Holders (unless it is specifically
required that the Required Holders act): (i) the Trustee shall execute an
appropriate instrument permitting any Person to take any action prohibited, or
omit the taking of any action required, by any of the provisions of this
Indenture or any indenture supplemental hereto, or any other Credit Document to
which the Trustee is a party or of which the Trustee is a third party
beneficiary or which is granted in favor of the Trustee ("Trustee Security
Document"), or (ii) the Issuer and the Trustee may enter into an indenture or
indentures supplemental hereto or to a Trustee Security Document for the purpose
of adding, changing or eliminating any provisions of this Indenture or of any
indenture supplemental hereto or to a Trustee Security Document or modifying in
any manner the rights of the holders of the Notes or the rights and obligations
of the Issuer; provided, that no such waiver, consent or supplemental indenture
or amendment shall (A) impair or affect the right of any Note Holder to receive
payments of the principal of and payments of the interest and any applicable
Make-Whole Amount (if any), Yield Protection Amount or Breakage Amount, if any,
on any Note held by it, as therein and herein provided including, without
limitation, the timing of any such payment or the principal amount of any Note
or rate of interest thereon, without the consent of such holder, (B) permit the
creating of any Lien with respect to any of the Trust Estate, without the
consent of the holders of all the Notes at the time Outstanding, (C) deprive the
holder of any Note of the benefit of the Liens held by the Trustee pursuant to
the terms of this Indenture or any other Credit Document without the consent of
such holder, (D) amend Article 2, Article 3, Article 4 or Article 6 (other than
an amendment of the nature described, and permitted by the provisions of,
Section 10.1), without the consent of the holders of all of the Notes at the
time Outstanding, (E) reduce the aforesaid percentage of the aggregate principal
amount of Notes, the holders of which are required to consent to any such waiver
or supplemental indenture or amendment pursuant to this Section 10.2, without
the consent of the holders of all of the Notes at the time Outstanding, or (F)
modify the rights, duties, or immunities of any Trustee, without the consent of
such Trustee. The holder of any Notes may specify that any such waiver or
consent shall be effective only with respect to a portion of the Notes held by
it (in which case it shall specify by dollar amount the aggregate principal
amount of Notes with respect to which such waiver or consent shall be effective)
and in the event of any such specification such holder shall be deemed to have
given such waiver or consent only with respect to the portion of Notes so
specified.

         (b) Notwithstanding the provisions of the foregoing subsection 10.2(a)
(and in addition to, and not in limitation of, any provisions of this Indenture,
the Note Purchase Agreements or any other Credit Documents specifically
requiring that the Required Holders act), (i) so long as there is no Indenture
Event of Default continuing hereunder, the Trustee shall not enter into any
indenture supplemental hereto (except as permitted by the foregoing Section
10.1), or agree to any amendment,

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<PAGE>   68



modification or waiver of any of the terms, conditions or provisions of this
Indenture or any indenture supplemental hereto, or any Trustee Security Document
without the consent of the Required Holders, and (ii) regardless of the
existence and continuance of any Indenture Event of Default, the Trustee shall
not (A) agree to any amendment, modification or waiver of any of the terms,
conditions or provisions of Section 12.16 of this Indenture, section 6 of the
Performance Agreement or section 5 of the Operating Services Agreement, the
effect of which would be to reduce, modify or amend any indemnities payable by
the Issuer or the Parent to any Note Holder (except to add additional
indemnities by the Issuer or the Parent), (B) agree to any amendment of the
definition of Indenture Event of Default or (C) agree to any amendment,
modification or waiver of any of the terms, conditions, or provisions of
Sections 7.3(c), 7.3(d)(i), 7.4(a) or 7.12 of this Indenture, sections 2.3,
3.3(c), 2.4, 2.9 or 2.13 of the First Naval Mortgage, section 2(a) of the
Performance Agreement or section 1(b) of the Operating Services Agreement.

         10.3 Notice of Supplemental Indenture. Promptly after the execution by
the Issuer and the Trustee of any supplemental indenture or promptly after the
execution by the Trustee of an appropriate instrument or permission pursuant to
the provisions of Section 10.2, the Trustee shall give written notice, setting
forth in general terms the substance of such supplemental indenture or
instrument, together with a conformed copy thereof to each holder of the Notes.
Any failure of the Trustee to give such notice, or any defect therein, shall
not, however, in any way impair or affect the validity of any such supplemental
indenture or instrument.

         10.4 Solicitation of Note Holders. So long as there are any Notes
Outstanding, the Issuer will not solicit, request or negotiate for or with
respect to any proposed waiver or amendment of any of the provisions of this
Indenture or the Notes unless each holder of the Notes shall be informed thereof
by the Issuer and shall be afforded the opportunity of considering the same and
shall be supplied by the Issuer with sufficient information to enable it to make
an informed decision with respect thereto. The Issuer will not, directly or
indirectly, pay or cause to be paid any remuneration, whether by way of
supplemental or additional interest, fee or otherwise, to any holder of Notes as
consideration for or as an inducement to entering into by any holder of Notes of
any waiver or amendment of any of the provisions of this Indenture or of any
Note unless such remuneration is concurrently offered to be paid, on the same
terms, ratably to the holders of all Notes then Outstanding even if such holder
did not consent to such waiver or amendment. Such remuneration will not be
inferred solely from the participation by a holder of the Notes in an existing
or future loan to or investment in or with the Issuer or any of its Affiliates.

         10.5 Opinion of Counsel Conclusive as to Supplemental Indentures. The
Trustee is hereby authorized to join with the Issuer in the execution of any
such supplemental indenture authorized or permitted by the terms of this
Indenture and to make the further agreements and stipulations which may be
therein contained, and the Trustee may receive an Opinion of Counsel as
conclusive evidence that any supplemental indenture executed pursuant to the
provisions of this Article 10 complies with the requirements of this Article 10.

         10.6 Effect of Supplemental Indentures. Upon the execution of any
supplemental indenture pursuant to the provisions of this Article 10, this
Indenture shall be deemed to be modified and amended in accordance therewith and
the respective rights, duties and obligations under this Indenture of the
Issuer, the Trustees and all holders of Notes thereunder shall thereafter be

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<PAGE>   69



determined, exercised and enforced hereunder subject in all respects to such
modification and amendment, and all the terms and conditions of any such
supplemental indenture shall be deemed to be part of the terms and conditions of
this Indenture for any and all purposes.

         10.7 New Notes. Notes executed and delivered after the execution of any
supplemental indenture pursuant to the provisions of this Article 10 may bear a
notation in form approved by the Trustee as to any matter provided for in such
supplemental indenture. If such supplemental indenture shall so provide, new
Notes, so modified as to conform, in the opinion of the Trustee and the Board of
Directors of the Issuer to any modification or amendment of this Indenture
contained in any such supplemental indenture, may be prepared by the Issuer,
executed and delivered without cost to the holders of Notes, upon surrender of
such Notes, in equal aggregate principal amounts.

ARTICLE 11.       UNCLAIMED MONIES.

         11.1 Satisfaction and Discharge of Agreement. If at any time (a) the
Issuer shall pay and discharge the entire indebtedness on all Notes hereunder by
paying or causing to be paid as provided in Article 4 the principal of, and any
applicable Make-Whole Amount, Yield Protection Amount and Breakage Amount and
interest on, all Notes hereunder, as and when the same become due and payable or
(b) all such Notes shall have been repurchased by the Issuer or an Affiliate of
the Issuer and canceled as herein provided (other than any Notes which shall
have been destroyed, lost or stolen and which shall have been replaced as
provided in Section 2.9); and if the Issuer shall also pay or cause to be paid
all other sums payable hereunder by the Issuer (including, without limitation,
fees and expenses of the Trustees), and the Issuer shall fully and faithfully
discharge, and cause to be faithfully discharged, every other obligation herein
and in each of the other Credit Documents contained, then and in that case this
Indenture shall cease, determine, and become null and void, and thereupon each
Trustee shall, upon Written Request of the Issuer or any other party to the
Credit Documents forthwith execute proper instruments acknowledging satisfaction
of and discharging this Indenture and releasing all Liens held by it pursuant to
the terms hereof and any other Credit Document, including the First Naval
Mortgage; provided, however, that in no event shall the trusts created by this
Indenture continue beyond the expiration of twenty-one (21) years after the
death of the last to die of all descendants living on the date of execution of
this Indenture of Joseph P. Kennedy, late father of the late President of the
United States, John F. Kennedy. The satisfaction and discharge of this Indenture
shall be without prejudice to the rights of each Trustee under Section 9.2 to
charge and be reimbursed by the Issuer for any expenditures which it may
thereafter incur in connection herewith.

         11.2 Return of Unclaimed Monies. Notwithstanding any provisions of this
Indenture, any monies deposited with any Trustee in trust for the payment of the
principal of, or interest or any applicable Make-Whole Amount on, any Notes and
remaining unclaimed for two (2) years after the last date on which any such
principal, interest or any applicable Make-Whole Amount shall have become due
and payable (whether at maturity or upon optional or required prepayment or by
declaration as provided in this Indenture), shall then be repaid to the Issuer
upon its Written Request, unless otherwise required by mandatory provisions of
applicable escheat or abandoned property laws, and the holders of such Notes,
unless otherwise required by mandatory provisions of applicable escheat or
abandoned property laws, shall thereafter be entitled to look only to the Issuer
for repayment thereof, and all liability of such Trustee with respect to such
monies shall thereupon

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<PAGE>   70



cease; provided, however, that before the repayment of such monies to the
Issuer, as aforesaid, such Trustee shall (at the cost of the Issuer) first mail
to all holders of the Notes then Outstanding at their addresses as set forth in
the register required to be maintained pursuant to Section 2.3, a notice that
said monies remain unclaimed and that, after a date named in said notice, which
date shall not be less than ten (10) or more than twenty (20) days after the
date of the first mailing of such notice, the balance of such monies then
unclaimed will be returned to the Issuer. In the event of the repayment of any
such monies to the Issuer as aforesaid, the holders of the Notes in respect of
which such monies were deposited shall thereafter be deemed to be unsecured
creditors of the Issuer for amounts equivalent to the respective amounts
deposited for the payment of such Notes and so repaid to the Issuer (without
interest thereon and subject to applicable escheat and abandoned property laws).

ARTICLE 12.       MISCELLANEOUS.

         12.1 Successors and Assigns. Whenever any of the parties hereto is
referred to, such reference shall be deemed to include the successors and
assigns of such party; and all the covenants, promises and agreements in this
Indenture contained by or on behalf of the Issuer, by or on behalf of a Trustee
or by or on behalf of a Purchaser, shall bind and inure to the benefit of the
respective successors and assigns of such parties whether so expressed or not;
provided; however, that the Issuer shall not assign or transfer any of its
rights or delegate any of its duties or obligations under the Credit Documents
without the prior written consent of the Majority Holders.

         12.2 Partial Invalidity. Any provision of this Indenture that is
prohibited or unenforceable in any jurisdiction shall, as to such jurisdiction,
be ineffective to the extent of such prohibition or unenforceability without
invalidating the remaining provisions hereof, and any such prohibition or
unenforceability in any jurisdiction shall (to the full extent permitted by law)
not invalidate or render unenforceable such provision in any other jurisdiction.

         12.3 Communications. All communications provided for herein shall be in
writing or by telecommunication device capable of creating a written record and
shall be deemed to have been given when delivered personally or otherwise
actually received by such Person listed below at its address set forth below:

                  If to the Issuer:

                           If by mail:

                           Noble Drilling (Paul Romano) Inc.
                           10370 Richmond Avenue, Suite 581
                           Houston, Texas 77042
                           Attention:  President


                           If by personal delivery:

                           Noble Drilling (Paul Romano) Inc.
                           10370 Richmond Avenue, Suite 581

                                      -65-


<PAGE>   71



                           Houston, Texas 77042
                           Attention:  President

                           in either case with a copy to:

                           Robert D. Campbell, Esq.
                           Thompson & Knight, P.C.
                           1700 Pacific Avenue, Suite 3300
                           Dallas, Texas 75201


                  If to the Trustee:

                           If by mail or personal delivery:

                           Chase Bank of Texas, National Association
                           600 Travis, Suite 1150, 11th Floor
                           Houston, Texas  77002
                           Attention:       Mauri Cowen
                                            Corporate Trust Dept.

or to either such party at such other address as such party may designate by
notice duly given in accordance with this Section to the other party. Where this
Indenture provides for any communication to holders of Notes, such communication
shall be deemed to have been given when delivered personally or otherwise
actually received by such holder at its last address as it appears in the
register required to be maintained pursuant to Section 2.3.

         12.4     GOVERNING LAW; SUBMISSION TO JURISDICTION.

                  (A) THIS INDENTURE AND THE NOTES (INCLUDING, BUT NOT LIMITED
         TO, THE VALIDITY AND ENFORCEABILITY HEREOF AND THEREOF) SHALL BE
         GOVERNED BY, AND CONSTRUED IN ACCORDANCE WITH, THE LAWS OF THE STATE OF
         NEW YORK OTHER THAN CONFLICT OF LAW RULES THEREOF THAT WOULD REQUIRE
         THE APPLICATION OF THE LAWS OF A JURISDICTION OTHER THAN SUCH STATE.

                  (B) ANY LEGAL ACTION OR PROCEEDING WITH RESPECT TO THE CREDIT
         DOCUMENTS MAY BE BROUGHT IN THE COURTS OF THE STATE OF NEW YORK OR OF
         THE UNITED STATES OF AMERICA FOR THE SOUTHERN DISTRICT OF NEW YORK,
         AND, BY EXECUTION AND DELIVERY OF THIS INDENTURE, EACH OF THE ISSUER
         AND THE TRUSTEES HEREBY ACCEPTS FOR ITSELF AND (TO THE EXTENT PERMITTED
         BY LAW) IN RESPECT OF ITS PROPERTY, GENERALLY AND UNCONDITIONALLY, THE
         JURISDICTION OF THE AFORESAID COURTS. EACH OF THE ISSUER AND THE
         TRUSTEES HEREBY IRREVOCABLY WAIVES ANY OBJECTION, INCLUDING, WITHOUT
         LIMITATION, ANY OBJECTION TO THE LAYING OF VENUE OR BASED ON THE
         GROUNDS OF FORUM NON CONVENIENS, WHICH IT MAY NOW OR HEREAFTER HAVE TO
         THE BRINGING OF ANY SUCH ACTION OR PROCEEDING IN SUCH RESPECTIVE
         JURISDICTIONS. THIS SUBMISSION TO JURISDICTION IS 

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<PAGE>   72

         NONEXCLUSIVE AND DOES NOT PRECLUDE THE PARTIES FROM OBTAINING
         JURISDICTION OVER OTHER PARTIES IN ANY COURT OTHERWISE HAVING
         JURISDICTION.

                  (C) THE ISSUER HEREBY IRREVOCABLY DESIGNATES CT CORPORATION
         LOCATED AT 1633 BROADWAY, NEW YORK, NEW YORK 10019, AS THE DESIGNEE,
         APPOINTEE AND AGENT OF THE ISSUER TO RECEIVE, FOR AND ON BEHALF OF THE
         ISSUER, SERVICE OF PROCESS IN SUCH JURISDICTION IN ANY LEGAL ACTION OR
         PROCEEDING WITH RESPECT TO THE CREDIT DOCUMENTS. IT IS UNDERSTOOD THAT
         A COPY OF SUCH PROCESS SERVED ON SUCH AGENT WILL BE PROMPTLY FORWARDED
         BY OVERNIGHT COURIER TO THE ISSUER AT ITS ADDRESS SET FORTH IN SECTION
         12.3 HEREOF, BUT THE FAILURE OF THE ISSUER TO RECEIVE SUCH COPY SHALL
         NOT AFFECT IN ANY WAY THE SERVICE OF SUCH PROCESS. THE ISSUER FURTHER
         IRREVOCABLY CONSENTS TO THE SERVICE OF PROCESS OF ANY OF THE
         AFOREMENTIONED COURTS IN ANY SUCH ACTION OR PROCEEDING BY THE MAILING
         OF COPIES THEREOF BY REGISTERED OR CERTIFIED MAIL, POSTAGE PREPAID, TO
         THE ISSUER AT ITS SAID ADDRESS, SUCH SERVICE TO BECOME EFFECTIVE THIRTY
         (30) DAYS AFTER SUCH MAILING.

                  (D) NOTHING HEREIN SHALL AFFECT THE RIGHT OF THE ISSUER OR THE
         TRUSTEES OR ANY HOLDER OF A NOTE TO SERVE PROCESS IN ANY OTHER MANNER
         PERMITTED BY LAW OR TO COMMENCE LEGAL PROCEEDINGS OR OTHERWISE PROCEED
         AGAINST THE ISSUER IN ANY OTHER JURISDICTION, INCLUDING WITHOUT
         LIMITATION, THE COMMENCEMENT OF ENFORCEMENT PROCEEDINGS UNDER THE
         CREDIT DOCUMENTS IN ALL APPLICABLE JURISDICTIONS.

                  (E) EACH OF THE ISSUER AND THE TRUSTEES HEREBY (I) IRREVOCABLY
         AND UNCONDITIONALLY WAIVE, TO THE FULLEST EXTENT PERMITTED BY LAW,
         TRIAL BY JURY IN ANY LEGAL ACTION OR PROCEEDING RELATING TO THIS
         AGREEMENT OR ANY OTHER CREDIT DOCUMENT AND FOR ANY COUNTERCLAIM
         THEREIN; (II) IRREVOCABLY WAIVE, TO THE MAXIMUM EXTENT NOT PROHIBITED
         BY LAW, ANY RIGHT IT MAY HAVE TO CLAIM OR RECOVER IN ANY SUCH
         LITIGATION ANY SPECIAL, EXEMPLARY, PUNITIVE OR CONSEQUENTIAL DAMAGES,
         OR DAMAGES OTHER THAN, OR IN ADDITION TO, ACTUAL DAMAGES; (III) CERTIFY
         THAT NO PARTY HERETO NOR ANY REPRESENTATIVE OR AGENT OF COUNSEL FOR ANY
         PARTY HERETO HAS REPRESENTED, EXPRESSLY OR OTHERWISE, OR IMPLIED THAT
         SUCH PARTY WOULD NOT, IN THE EVENT OF LITIGATION, SEEK TO ENFORCE THE
         FOREGOING WAIVERS, AND (IV) ACKNOWLEDGE THAT IT HAS BEEN INDUCED TO
         ENTER INTO THIS AGREEMENT AND THE OTHER CREDIT DOCUMENTS AND THE
         TRANSACTIONS CONTEMPLATED HEREBY AND THEREBY BY, AMONG OTHER THINGS,
         THE MUTUAL WAIVERS AND CERTIFICATIONS CONTAINED IN THIS SECTION 12.4.

         12.5     Limitation on Interest.

                  (a) It is the intent of the parties hereto to comply strictly
         with applicable usury laws, and the parties hereto stipulate and agree
         that none of the terms and provisions contained in this Indenture, the
         Notes or any other Credit Documents shall ever be construed to create a
         contract to pay, for the use, forbearance or detention of money,
         interest in excess of the maximum amount of interest permitted to be
         charged by applicable law from time to

                                      -67-


<PAGE>   73



         time in effect. If any excess of interest in such respect is hereby
         provided for or shall be adjudicated to be so provided, in this
         Indenture, in any Note or otherwise in connection with the Credit
         Documents, the provisions of this Section 12.5 shall govern and
         prevail, and neither the Issuer nor any present or future guarantors,
         endorsers, or other Persons hereafter becoming liable for payment of
         the Notes shall ever be obligated to pay the excess amount of such
         interest. The provisions of this Section 12.5 shall control over all
         other provisions of the Credit Documents which may be in conflict or
         apparent conflict herewith. Each of the Trustees and the holders of the
         Notes expressly disavows any intention to charge, collect or contract
         for excessive unearned interest or finance charges in the event the
         maturity of any of the Notes is accelerated. If the maturity of a Note
         is accelerated for any reason, any amounts held to constitute interest
         (including any applicable Make-Whole Amount, Yield Protection Amount or
         Breakage Amount due upon acceleration if such applicable Make-Whole
         Amount, Yield Protection Amount or Breakage Amount is held to
         constitute interest under applicable law) which are then unearned and
         have theretofore been collected by any Trustee or the holder of such
         Note shall be applied as of the date of receipt thereof to reduce the
         principal balance thereof then outstanding and if the principal of the
         Notes has been paid in full, any remaining excess shall be forthwith
         paid to the Issuer. If any Trustee or any holder of any Note shall
         receive, collect or apply monies which are deemed to constitute
         interest which would otherwise increase the interest on such Note to an
         amount in excess of that permitted to be charged by applicable law then
         in effect, all such sums deemed to constitute interest in excess of
         such legal limit shall be applied to reduce the principal balance
         thereof then outstanding or immediately returned to the Issuer or the
         other payor thereof upon such determination. All sums paid or agreed to
         be paid to any Trustee or holder of any Note for the use, forbearance
         or detention of sums due hereunder shall, to the extent permitted by
         law applicable to such party, be amortized, prorated, allocated and
         spread throughout the full term of the indebtedness evidenced by the
         Notes until payment in full so that the rate or amount of interest on
         account of any indebtedness hereunder does not exceed the maximum
         amount allowed by such applicable law. If at any time and from time to
         time (i) the amount of interest payable to any holder of a Note on any
         date shall be pursuant to this Section 12.5 be limited and (ii) in
         respect of any subsequent interest computation period the amount of
         interest otherwise payable to such holder would be less than the amount
         of interest payable to such holder computed at the maximum lawful rate
         applicable to such holder, then the amount of interest payable to such
         holder in respect to such subsequent interest computation period shall
         continue to be computed at the maximum lawful rate applicable to such
         holder until the total amount of interest payable to such holder shall
         equal the total amount of interest which would have been payable to
         such holder if the total amount of interest had been computed without
         giving effect to this Section 12.5. As used in this section the term
         "applicable law" means the laws of the State of New York or the laws of
         the United States of America, whichever laws allow the greater
         interest, as such laws now exist or may be changed or amended or come
         into effect in the future.

                  (b) All proceeds of the sale of the Notes are to be delivered
         by the Purchasers to the Issuer and used by the Issuer as represented
         in Section 5.14 of the Note Purchase Agreements.


                                      -68-


<PAGE>   74



                  (c) Notwithstanding any term or provision contained in this
         Indenture, the Notes or any other Credit Document to the contrary the
         Make-Whole Amount, Yield Protection Amount and/or Breakage Amount shall
         be charged and payable only to the extent permitted by applicable law.

         12.6 Counterparts. This Indenture may be executed, acknowledged and
delivered in any number of counterparts, each of such counterparts constituting
an original but all together only one Indenture; provided, however, that this
Indenture shall not be deemed to be delivered until at least one counterpart
shall have been executed by the Issuer and the Trustee and a counterpart so
executed shall have been delivered to the Trustee at its principal place of
business specified in Section 12.3.

         12.7 Headings, etc.; Gender. Any headings or captions preceding the
text of the several sections hereof are intended solely for convenience of
reference and shall not constitute a part of this Indenture nor shall they
affect its meaning, construction or effect. Each covenant contained in this
Indenture shall be construed (absent an express contrary provision therein) as
being independent of each and every other covenant contained herein and
compliance with any one covenant shall not (absent such an express contrary
provision) be deemed to excuse compliance with any and all other covenants. All
references herein or in any other Credit Document to the masculine, feminine or
neuter gender shall also include and refer to each other gender not so referred
to.

         12.8 Amendments. This Indenture may, subject to the provisions of
Article 10 hereof, from time to time and at any time, be amended or supplemented
by an instrument or instruments in writing executed by the parties hereto.

         12.9 Benefits of Agreement Restricted to Parties and Note Holders.
Nothing in this Indenture expressed or implied is intended or shall be construed
to give to any Person other than the Issuer, the Trustees, the Credit Support
Parties and the holders of the Notes, any legal or equitable right, remedy or
claim under or in respect of this Indenture or any covenant, condition or
provision therein or herein contained; and all such covenants, conditions and
provisions are and shall be held to be for the sole and exclusive benefit of the
Issuer, the Trustees and the holders of the Notes issued hereunder.

         12.10 Waiver of Notice. Whenever in this Indenture the giving of notice
by mail or otherwise is required, the giving of such notice may be waived in
writing by the Person or Persons entitled to receive such notice.

         12.11 Intentionally Omitted.

         12.12 Additional Financing Statement Filings. The Issuer hereby
authorizes the Trustee to file, without the signature of the Issuer where
permitted by law, one or more financing or continuation statements, and
amendments thereto, relating to the Collateral. The Issuer further agrees that a
carbon, photographic or other reproduction of any Credit Document or any
financing statement describing any Collateral is sufficient as a financing
statement and may be filed in any jurisdiction the Trustee may deem appropriate.


                                      -69-


<PAGE>   75



         12.13 Directly or Indirectly. Where any provision in this Indenture
refers to action to be taken by any Person, or which such Person is prohibited
from taking, such provision shall be applicable whether such action is taken
directly or indirectly by such Person, including actions taken by or on behalf
of any partnership in which such Person is a general partner.

         12.14 Exhibits, Annexes and Sections. All references herein to
Exhibits, Annexes or Sections shall be to the Exhibits and Annexes attached to
this Indenture and to the Sections hereof unless the context otherwise requires
reference to an exhibit, annex to or section of another document. All Exhibits
and Annexes attached to this Indenture are made a part hereof for all purposes.
The words "this Indenture," "this instrument," "herein," "hereof," "hereby,"
"hereunder," and words of similar import refer to this Indenture as a whole and
not to any particular subdivision unless expressly so limited. The phrases "this
section" and "this subsection" and similar phrases refer only to the sections or
subsections hereof in which such phrases occur. The word "or" is not exclusive.

         12.15 Officers' Certificate and Opinions of Counsel; Statements to be
Contained Therein.

                  (a) Upon any request, application or demand by the Issuer to
         the Trustee to take any action under any of the provisions of this
         Indenture, the Issuer shall furnish to the Trustee a certificate signed
         by two of its Responsible Officers stating that all conditions
         precedent provided for in this Indenture relating to the proposed
         action have been complied with and an Opinion of Counsel stating that
         in the opinion of such counsel all such conditions precedent (to which
         a legal opinion is reasonably appropriate) have been complied with,
         except that in the case of any such request, application or demand as
         to which the furnishing of such documents is specifically required by
         any provision of this Indenture relating to such particular request,
         application or demand, no additional certificate or opinion need be
         furnished.

                  (b) Each certificate or opinion provided for in this Indenture
         and delivered to the Trustee with respect to compliance with a
         condition or covenant provided for in this Indenture shall include (i)
         a statement that the person making such certificate or opinion has read
         such covenant or condition, (ii) a brief statement as to the nature and
         scope of the examination or investigation upon which the statements or
         opinions contained in such certificate or opinion are based, (iii) a
         statement that, in the opinion of such person, he has made such
         examination or investigation as is necessary to enable him to express
         an informed opinion as to whether or not such covenant or condition has
         been complied with, and (iv) a statement as to whether or not, in the
         opinion of such person, such condition or covenant has been complied
         with.

                  (c) Any certificate, statement or opinion of an officer of the
         Issuer may be based, insofar as it relates to legal matters, upon a
         certificate or opinion of or representations by counsel, unless such
         officer has actual knowledge that the certificate or opinion or
         representations with respect to the matters upon which his certificate,
         statement or opinion may be based as aforesaid are erroneous, or in the
         exercise of reasonable care should know that the same are erroneous.
         Any certificate, statement or opinion of counsel may be based, insofar
         as it relates to factual matters, upon information with respect to
         which is in the

                                      -70-


<PAGE>   76



         possession of the Issuer, upon the certificate, statement or opinion of
         or representations by a Responsible Officer or Officers of the Issuer,
         unless such counsel has actual knowledge that the certificate,
         statement or opinion or representations with respect to the matters
         upon which his certificate, statement or opinion may be based as
         aforesaid are erroneous.

                  (d) Any certificate, statement or opinion of an officer of the
         Issuer or of counsel may be based, insofar as it relates to accounting
         matters, upon a certificate or opinion of or representations by an
         accountant or firm of accountants in the employ of the Issuer or an
         Affiliate thereof, unless such officer or counsel, as the case may be,
         has actual knowledge that the certificate or opinion or representations
         with respect to the accounting matters upon which his certificate,
         statement or opinion may be based as aforesaid are erroneous, or in the
         exercise of reasonable care should know that the same are erroneous.

                  (e) Any certificate or opinion of any independent firm of
         public accountants filed with the Trustee shall contain a statement
         that such firm is independent.

         12.16 Payment of Expenses, Indemnities, etc. The Issuer agrees:

                  (a) to pay all reasonable expenses of the Trustees in the
         administration (both before and after the execution hereof and
         including advice of counsel as to the rights and duties of the Trustees
         and the Note Holders with respect thereto) of, and in connection with
         the negotiation, investigation, preparation, execution and delivery of,
         recording or filing of, preservation of rights under, enforcement of,
         and refinancing, renegotiation or restructuring of, any Credit Document
         and any proposed amendment, waiver or consent, whether or not adopted,
         relating thereto (including, without limitation, travel, photocopy,
         mailing, courier, telephone and other similar expenses of the Trustees,
         the reasonable fees and disbursements of external counsel and other
         outside consultants for the Trustees and, in the case of enforcement,
         the reasonable fees and disbursements of external counsel for the
         Trustees and any of the Note Holders; provided that to the extent it is
         feasible and a conflict of interest does not exist in the reasonable
         judgment of the Series A Note Holders or Series B Note Holders as
         applicable, the Series A Note Holders shall all use the same counsel
         and the Series B Note Holders shall all use the same counsel); and
         promptly reimburse the Trustees and the Note Holders for all amounts
         expended, advanced or incurred by the Trustees and any of the Note
         Holders to satisfy any obligation of the Issuer under this Indenture or
         any other Credit Document, including without limitation, all costs and
         expenses of foreclosure;

                  (b) TO INDEMNIFY EACH TRUSTEE, EACH NOTE HOLDER AND EACH
         CREDIT SUPPORT PARTY AND EACH OF THEIR AFFILIATES AND EACH OF THEIR
         OFFICERS, DIRECTORS, EMPLOYEES, REPRESENTATIVES, AGENTS, ATTORNEYS,
         ACCOUNTANTS AND EXPERTS ("INDEMNIFIED PARTIES") FROM, HOLD EACH OF THEM
         HARMLESS AGAINST AND PROMPTLY UPON DEMAND PAY OR REIMBURSE EACH OF THEM
         FOR, THE INDEMNITY MATTERS WHICH MAY BE INCURRED BY OR ASSERTED AGAINST
         OR INVOLVE ANY OF THEM (WHETHER OR NOT ANY OF THEM IS DESIGNATED A
         PARTY THERETO) AS A RESULT OF, ARISING OUT OF OR IN ANY WAY RELATED TO
         (I) ANY ACTUAL OR PROPOSED USE BY THE ISSUER OF THE PROCEEDS OF ANY OF
         THE NOTES, (II) THE EXECUTION, DELIVERY AND PERFORMANCE OF THE CREDIT
         DOCUMENTS, (III) THE OPERATIONS OF THE BUSINESS OF

                                      -71-


<PAGE>   77



         THE ISSUER OR ANY AFFILIATE THEREOF (IV) THE FAILURE OF THE ISSUER OR
         ANY AFFILIATE THEREOF TO COMPLY WITH THE TERMS OF ANY CREDIT DOCUMENT
         INCLUDING, WITHOUT LIMITATION, THE PERFORMANCE AGREEMENT OR THIS
         INDENTURE, OR WITH ANY GOVERNMENTAL REQUIREMENT, (V) ANY INACCURACY OF
         ANY REPRESENTATION OR ANY BREACH OF ANY WARRANTY OR COVENANT OF THE
         ISSUER OR ANY AFFILIATE THEREOF SET FORTH IN ANY OF THE CREDIT
         DOCUMENTS, (VI) ANY ASSERTION THAT THE TRUSTEE OR THE NOTE HOLDERS WERE
         NOT ENTITLED TO RECEIVE THE PROCEEDS RECEIVED PURSUANT TO THE CREDIT
         DOCUMENTS OR (VI) ANY OTHER ASPECT OF THE CREDIT DOCUMENTS, INCLUDING,
         WITHOUT LIMITATION, THE REASONABLE FEES AND DISBURSEMENTS OF COUNSEL
         AND ALL OTHER EXPENSES INCURRED IN CONNECTION WITH INVESTIGATING,
         DEFENDING OR PREPARING TO DEFEND ANY SUCH ACTION, SUIT, PROCEEDING
         (INCLUDING ANY INVESTIGATIONS, LITIGATION OR INQUIRIES) OR CLAIM AND
         INCLUDING ALL INDEMNITY MATTERS ARISING BY REASON OF THE ORDINARY
         NEGLIGENCE OF ANY INDEMNIFIED PARTY, BUT EXCLUDING ALL INDEMNITY
         MATTERS ARISING SOLELY BY REASON OF CLAIMS BETWEEN THE NOTE HOLDERS OR
         A NOTE HOLDER AND A NOTE HOLDER'S SHAREHOLDER OR SOLELY BY REASON OF
         THE GROSS NEGLIGENCE OR WILLFUL MISCONDUCT ON THE PART OF THE
         INDEMNIFIED PARTY; AND

                  (c) TO INDEMNIFY AND HOLD HARMLESS THE INDEMNIFIED PARTIES
         FROM AND AGAINST ANY AND ALL LOSSES, CLAIMS, COST RECOVERY ACTIONS,
         ADMINISTRATIVE ORDERS OR PROCEEDINGS, DAMAGES AND LIABILITIES TO WHICH
         ANY SUCH PERSON MAY BECOME SUBJECT IN CONNECTION WITH THIS INDENTURE,
         THE NOTE PURCHASE AGREEMENTS OR ANY OTHER CREDIT DOCUMENT (I) UNDER ANY
         ENVIRONMENTAL LAW, (II) AS A RESULT OF THE BREACH OR NON-COMPLIANCE BY
         THE ISSUER OR ANY AFFILIATE THEREOF WITH ANY ENVIRONMENTAL LAW
         APPLICABLE TO THE ISSUER OR ANY AFFILIATE THEREOF, (III) DUE TO PAST
         OWNERSHIP BY THE ISSUER OR ANY AFFILIATE THEREOF OF ANY OF THEIR
         PROPERTIES OR PAST ACTIVITY ON ANY OF THEIR PROPERTIES WHICH, THOUGH
         LAWFUL AND FULLY PERMISSIBLE AT THE TIME, COULD RESULT IN PRESENT OR
         FUTURE LIABILITY, (IV) THE PRESENCE, USE, RELEASE, DISCHARGE, STORAGE,
         TREATMENT OR DISPOSAL OF HAZARDOUS SUBSTANCES OR OIL ON OR AT ANY OF
         THE PROPERTIES NOW OR FORMERLY OWNED OR OPERATED BY THE ISSUER OR ANY
         AFFILIATE THEREOF, OR (V) ANY OTHER ENVIRONMENTAL, HEALTH OR SAFETY
         CONDITION IN CONNECTION WITH THE CREDIT DOCUMENTS, PROVIDED, HOWEVER,
         NO INDEMNITY SHALL BE AFFORDED UNDER THIS SECTION 12.16 IN RESPECT OF
         ANY PROPERTY FOR ANY OCCURRENCE ARISING SOLELY FROM THE ACTS OR
         OMISSIONS (IN EACH CASE CONSTITUTING GROSS NEGLIGENCE OR WILFUL
         MISCONDUCT) OF A TRUSTEE OR ANY NOTE HOLDER ARISING DURING THE PERIOD
         AFTER WHICH SUCH PERSON, ITS SUCCESSORS OR ASSIGNS SHALL HAVE OBTAINED
         POSSESSION OF SUCH PROPERTY (WHETHER BY FORECLOSURE OR DEED IN LIEU OF
         FORECLOSURE, AS MORTGAGEE-IN-POSSESSION OR OTHERWISE).

                  (d) So long as no Indenture Default or Indenture Event of
         Default has occurred and is continuing, no Indemnified Party may settle
         any claim to be indemnified without the consent of the indemnitor, such
         consent not to be unreasonably withheld; provided, that the indemnitor
         may not reasonably withhold consent to any settlement that an
         Indemnified Party

                                      -72-


<PAGE>   78



         proposes, if the indemnitor does not have the financial ability to pay
         all its obligations outstanding and asserted against the indemnitor at
         that time, including the maximum potential claims against the
         Indemnified Party to be indemnified pursuant to this Section 12.16.

                  (e) In the case of any indemnification hereunder, an
         Indemnified Party shall give notice to the Issuer of any claim or
         demand being made against it; provided, however, that the failure to
         give such notice shall not release the Issuer from any of its
         obligations, except to the extent that failure to give notice of any
         action, suit or proceeding against such Indemnified Party shall prevent
         the Issuer's ability to contest such claim or demand. Subject to the
         provisions of the following paragraph, the Issuer shall at its sole
         cost and expense be entitled to control, and shall assume full
         responsibility for, the defense of such claim or liability; provided
         that the Issuer shall keep the Indemnified Party which is the subject
         of such proceeding fully apprised of the status of such proceeding and
         shall provide such Indemnified Party with all information with respect
         to such proceeding as such Indemnified Person shall reasonably request.

         Notwithstanding any of the foregoing to the contrary, the Issuer shall
not be entitled to control and assume responsibility for the defense of such
claim or liability if (i) an Indenture Event of Default shall have occurred and
be continuing, (ii) such proceeding will involve any possibility of the sale,
forfeiture or loss of, or the creation of any Lien (other than an Excepted Lien
or a Lien which is adequately bonded to the satisfaction of such Indemnified
Party) on, the Trust Estate or any part thereof, (iii) in the good faith opinion
of such Indemnified Party, there exists an actual or potential conflict of
interest such that it is advisable for such Indemnified Person to retain control
of such proceeding or (iv) such claim or liability involves the possibility of
criminal sanctions or liability to such Indemnified Party. In the circumstances
described in clauses (i) - (iv), the Indemnified Party shall be entitled to
control and assume responsibility for the defense of such claim or liability at
the expense of the Issuer. In addition, any Indemnified Party may participate in
any proceeding controlled by the Issuer, at its own expense in respect of any
such proceeding as to which the Issuer shall have acknowledged in writing its
obligation to indemnify the Indemnified Party, and at the expense of the Issuer
in respect of any such proceeding as to which the Issuer shall not have so
acknowledged its obligation to the Indemnified Party, the Issuer may in any
event participate in all such proceedings at its own cost. Nothing contained
herein shall be deemed to require an Indemnified Party to contest any claim or
demand or to assume responsibility for or control of any judicial proceeding
with respect thereto.

                  (f) THE FOREGOING INDEMNITIES SHALL EXTEND TO THE INDEMNIFIED
         PARTIES NOTWITHSTANDING THE SOLE OR CONCURRENT NEGLIGENCE OF EVERY KIND
         OR CHARACTER WHATSOEVER, WHETHER ACTIVE OR PASSIVE, WHETHER AN
         AFFIRMATIVE ACT OR AN OMISSION, INCLUDING WITHOUT LIMITATION, ALL TYPES
         OF NEGLIGENT CONDUCT IDENTIFIED IN THE RESTATEMENT (SECOND) OF TORTS OF
         ONE OR MORE OF THE INDEMNIFIED PARTIES OR BY REASON OF STRICT LIABILITY
         IMPOSED WITHOUT FAULT ON ANY ONE OR MORE OF THE INDEMNIFIED PARTIES. TO
         THE EXTENT THAT AN INDEMNIFIED PARTY IS FOUND TO HAVE COMMITTED AN ACT
         OF GROSS NEGLIGENCE OR WILLFUL MISCONDUCT, THIS CONTRACTUAL OBLIGATION
         OF INDEMNIFICATION AS TO SUCH

                                      -73-


<PAGE>   79



         INDEMNIFIED PARTY SHALL CONTINUE BUT SHALL ONLY EXTEND TO THE PORTION
         OF THE CLAIM THAT IS DEEMED TO HAVE OCCURRED BY REASON OF EVENTS OTHER
         THAN THE GROSS NEGLIGENCE OR WILLFUL MISCONDUCT OF THE INDEMNIFIED
         PARTY.

                  (g) The Issuer's obligations under this Section 12.16 shall
         survive any termination of this Indenture or any other Credit Document
         and the payment of the Notes and shall continue thereafter in full
         force and effect.

                  (h) The Issuer shall pay any amounts due under this Section
         12.16 within thirty (30) days of the receipt by the Issuer of notice of
         the amount due.

                  (i) If any amounts due by the Issuer to the Trustees or any
         Note Holder under this Section 12.16 or any other provision of this
         Agreement or any other Credit Document is not paid on the date due,
         such amounts shall bear interest and Issuer agrees to pay such amounts
         with interest at the Default Rate from the due date of such payable
         until paid.

         12.17 NO ORAL AGREEMENTS. THE CREDIT DOCUMENTS EMBODY THE ENTIRE
AGREEMENT AND UNDERSTANDING BETWEEN THE PARTIES AND SUPERSEDE ALL OTHER
AGREEMENTS AND UNDERSTANDINGS BETWEEN SUCH PARTIES RELATING TO THE SUBJECT
MATTER HEREOF AND THEREOF. THE CREDIT DOCUMENTS REPRESENT THE FINAL AGREEMENT
BETWEEN THE PARTIES AND MAY NOT BE CONTRADICTED BY EVIDENCE OF PRIOR, CONTEMPO
RANEOUS OR SUBSEQUENT ORAL AGREEMENTS OF THE PARTIES. THERE ARE NO UNWRITTEN
ORAL AGREEMENTS BETWEEN THE PARTIES.

         12.18 EXCULPATION PROVISIONS. EACH OF THE PARTIES HERETO SPECIFICALLY
AGREES THAT IT HAS A DUTY TO READ THIS INDENTURE AND THE OTHER CREDIT DOCUMENTS
AND AGREES THAT IT IS CHARGED WITH NOTICE AND KNOWLEDGE OF THE TERMS OF THIS
INDENTURE AND THE OTHER CREDIT DOCUMENTS; THAT IT HAS IN FACT READ THIS
INDENTURE AND IS FULLY INFORMED AND HAS FULL NOTICE AND KNOWLEDGE OF THE TERMS,
CONDITIONS AND EFFECTS OF THIS INDENTURE; THAT IT HAS BEEN REPRESENTED BY
INDEPENDENT LEGAL COUNSEL OF ITS CHOICE THROUGHOUT THE NEGOTIATIONS PRECEDING
ITS EXECUTION OF THIS INDENTURE AND THE OTHER CREDIT DOCUMENTS; AND HAS RECEIVED
THE ADVICE OF ITS ATTORNEY IN ENTERING INTO THIS INDENTURE AND THE OTHER CREDIT
DOCUMENTS; AND THAT IT RECOGNIZES THAT CERTAIN OF THE TERMS OF THIS INDENTURE
AND THE OTHER CREDIT DOCUMENTS RESULT IN ONE PARTY ASSUMING THE LIABILITY
INHERENT IN SOME ASPECTS OF THE TRANSACTION AND RELIEVING THE OTHER PARTY OF ITS
RESPONSIBILITY FOR SUCH LIABILITY. EACH PARTY HERETO AGREES AND COVENANTS THAT
IT WILL NOT CONTEST THE VALIDITY OR ENFORCEABILITY OF ANY EXCULPATORY PROVISION
OF THIS INDENTURE AND THE OTHER CREDIT DOCUMENTS ON THE BASIS THAT THE PARTY HAD
NO NOTICE OR KNOWLEDGE OF SUCH PROVISION OR THAT THE PROVISION IS NOT
"CONSPICUOUS."

         12.19 Trustees Not Engaging in a Trade or Business. The trusts created
hereunder have been organized for the purposes described herein with no
objective by the Trustees to engage in the conduct of a trade or business. The
Trustees shall report the trusts for federal income tax purposes as a "grantor
trust" subject to the provisions of Subchapter J, subpart E of the Code unless
otherwise required.

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<PAGE>   80




                        [Signature Pages Start Next Page]









                                      -75-


<PAGE>   81



         IN WITNESS WHEREOF, the parties hereto have caused this Indenture to be
duly executed by their respective officers thereunto duly authorized, and their
respective corporate seals to be hereunder affixed and attested, all as of the
day and year first written above.

Witnesses to all Signatures



- - ---------------------------------


- - ---------------------------------

ATTEST:                                 NOBLE DRILLING (PAUL ROMANO) INC.



                                        By
- - ---------------------------------         ----------------------------------
Name:                                   Name:
Title:                                  Title:

                  (seal)


ATTEST:                                 CHASE BANK OF TEXAS,
                                         NATIONAL ASSOCIATION



                                        By
- - ---------------------------------         ----------------------------------
Name:                                   Name:
Title:                                  Title:

                  (seal)



                                      -75-


<PAGE>   82



                                                                       ANNEX A-1


                        NOBLE DRILLING (PAUL ROMANO) INC.

No. AR-_____


         _____% SERIES A SENIOR SECURED NOTE DUE _____________, _______


$
 --------------------                                      --------------------


                  THE SECURITY (OR ITS PREDECESSOR) EVIDENCED
         HEREBY WAS ORIGINALLY ISSUED IN A TRANSACTION EXEMPT
         FROM REGISTRATION UNDER SECTION 5 OF THE UNITED STATES
         SECURITIES ACT OF 1933, AS AMENDED (THE "SECURITIES
         ACT"), AND THE SECURITY EVIDENCED HEREBY MAY NOT BE
         OFFERED, SOLD OR OTHERWISE TRANSFERRED IN THE ABSENCE OF
         SUCH REGISTRATION OR AN APPLICABLE EXEMPTION THEREFROM.
         THE HOLDER OF THE SECURITY EVIDENCED HEREBY IS HEREBY
         NOTIFIED THAT THE ISSUER IS NOT REQUIRED TO REGISTER
         THIS SECURITY UNDER THE SECURITIES ACT. THE HOLDER OF
         THE SECURITY EVIDENCED HEREBY AGREES FOR THE BENEFIT OF
         THE COMPANY THAT SUCH SECURITY MAY BE RESOLD, PLEDGED OR
         OTHERWISE TRANSFERRED, ONLY (1) IN ACCORDANCE WITH AN
         EXEMPTION FROM THE REGISTRATION REQUIREMENTS OF THE
         SECURITIES ACT, OR (2) PURSUANT TO AN EFFECTIVE
         REGISTRATION STATEMENT AND, IN EACH CASE, IN ACCORDANCE
         WITH ANY APPLICABLE SECURITIES LAWS OF ANY STATE OF THE
         UNITED STATES OR ANY OTHER APPLICABLE JURISDICTION.

         NOBLE DRILLING (PAUL ROMANO) INC., a Delaware corporation (the
"Company"), for value received, hereby promises to pay to
_________________________ or registered assigns the principal sum of
_________________________ Dollars ($__________) on ______________, 20__ , and to
pay interest (computed on the basis of a 360-day year of twelve 30-day months)
on the unpaid principal balance thereof from the date of this Note at the rate
of _____% per annum, monthly on the twentieth (20th) day of each month of each
year, commencing on _____________, until the principal amount hereof shall
become due and payable and to pay on demand interest on any overdue principal,
including any overdue prepayment of principal, and (to the extent permitted by
applicable law) on any applicable Make-Whole Amount or overdue installment of
interest, at a rate of interest per annum equal to the Default Rate; provided
that interest on this Note shall in no event exceed the maximum rate permitted
by applicable law, and this Note is expressly made subject to Section 12.5 of
the Indenture.

         Payments of principal, applicable Make-Whole Amount, if any, or other
amounts due hereon, and interest shall be made in any coin or currency of the
United States of America as at the time of payment is legal tender for the
payment of public and private debts in installments in such manner and at such
place as provided in Section 4.6 of the Indenture.

         This Note is one of an issue of Series A Senior Secured Notes of the
Company issued in an aggregate original principal amount limited to $95,412,500
under the Trust Indenture and Security Agreement of the Company (said indenture,
together with all agreements and indentures supplemental thereto being herein
called the "Indenture") dated as of ___________, 1998, with Chase Bank of Texas,
National Association as Trustee and is entitled to the benefits thereof.
Reference is hereby made to the Indenture for a description of certain rights,
obligations and duties of the parties thereto and for the meanings assigned to
terms used and not defined in this Note. As

                  


<PAGE>   83



provided in the Indenture, this Note is subject to optional prepayment. The
Company agrees to make required prepayments on account of this Note in
accordance with the prepayment schedule attached to this Note and in accordance
with the provisions of the Indenture. This Note is secured as set forth in the
Indenture and in the separate Note Purchase Agreements dated as of September __,
1998, between the Company and each of the Purchasers (listed on Schedule A
attached thereto).

         This Note is a registered Note and is transferable only by surrender
thereof at the agency of the Company maintained pursuant to Section 7.9 of the
Indenture, duly endorsed or accompanied by a written instrument of transfer duly
executed by the registered holder of this Note or its attorney duly authorized
in writing.

         Following any partial prepayment of this Note, this Note shall, prior
to any transfer hereof, be (a) made available to the Trustee for notation on the
prepayment schedule attached hereto of the amount of principal so prepaid or,
(b) at the option of the holder hereof and in lieu of the alternative in the
foregoing clause (a), held by the holder who shall make a notation of such
schedule of the amount of principal so prepaid. In case the entire principal
amount on this Note is prepaid or paid, this Note shall, upon written request
therefor by the Company, be surrendered promptly at the agency of the Company
maintained pursuant to Section 7.9 of the Indenture, for cancellation.

         In any case where the date of maturity of any interest, applicable
Make-Whole amount, or other amount due hereon, or principal owed with respect to
this Note or the date fixed for any prepayment (in whole or in part) of this
Note will not be a Business Day, then payment of such interest, applicable
Make-Whole Amount, or other amount due hereon, or principal need not be made on
such date but may be made on the next succeeding Business Day with the same
force and effect as if made on the date of maturity or the date fixed for such
prepayment.

         Under certain circumstances, as specified in the Indenture, the
principal of this Note (together with interest accrued thereon and any
applicable Make-Whole Amount) may be declared due and payable in the manner and
with the effect provided in the Indenture.

         This Note and the Indenture are governed by, and shall be construed and
enforced in accordance with, the law of the State of New York applicable to
contracts made and to be performed entirely within such state and applicable
federal law.

Dated:
      -------------------------

ATTEST:                                   NOBLE DRILLING (PAUL ROMANO) INC.


                                          By
- - -------------------------------             ----------------------------------
Assistant Secretary                                Name:
                                                        ----------------------
                                                   Title:
                                                         ---------------------
[CORPORATE SEAL]



                                       -2-


<PAGE>   84





         This is one of the Series A Notes described in the Indenture referred
to herein.

                               CHASE BANK OF TEXAS, NATIONAL ASSOCIATION,
                               as Trustee



                               By
                                 ----------------------------------------------
                                        Name:
                                             ----------------------------------
                                        Its:
                                            -----------------------------------


                                       -3-


<PAGE>   85



                             PREPAYMENT SCHEDULE TO
                           NOTE NO. AR-_______________
                                   (SERIES A)


         In addition to paying the entire outstanding principal amount of, and
the interest due on, this Note on _______________, 20__, the maturity date
hereof, the Company agrees to prepay, and there shall become due and payable,
principal amounts of this Note on the last day of each month, in each year,
beginning on ___________, 1998, as follows:


                Date Due                                Amount Due
                --------                                ----------




















                                       -4-


<PAGE>   86




                                 ASSIGNMENT FORM

         To assign this Note, fill in the form below: (I) or (we) assign and
transfer this Note to



- - -------------------------------------------------------------------------------
                  (Insert assignee's soc. sec. or tax I.D. no.)








- - -------------------------------------------------------------------------------
              (Print or type assignee's name, address and zip code)

and irrevocably appoint____________________________________________________
to transfer this Note on the books of the Company. The agent may substitute
another to act for him.



Date:

                              Your Signature:
                                             ----------------------------------
                              (Sign exactly as your name appears on the face of 
                               this Note)

                              Signature Guarantee:
                                                  -----------------------------



                                       -5-


<PAGE>   87



                                                                       ANNEX A-2

                        NOBLE DRILLING (PAUL ROMANO) INC.

No. BR-_____

         _____% SERIES B SENIOR SECURED NOTE DUE _____________, _______


$
 ------------------------                              ------------------------


                  THE SECURITY (OR ITS PREDECESSOR) EVIDENCED
         HEREBY WAS ORIGINALLY ISSUED IN A TRANSACTION EXEMPT
         FROM REGISTRATION UNDER SECTION 5 OF THE UNITED STATES
         SECURITIES ACT OF 1933, AS AMENDED (THE "SECURITIES
         ACT"), AND THE SECURITY EVIDENCED HEREBY MAY NOT BE
         OFFERED, SOLD OR OTHERWISE TRANSFERRED IN THE ABSENCE OF
         SUCH REGISTRATION OR AN APPLICABLE EXEMPTION THEREFROM.
         THE HOLDER OF THE SECURITY EVIDENCED HEREBY IS HEREBY
         NOTIFIED THAT THE ISSUER IS NOT REQUIRED TO REGISTER
         THIS SECURITY UNDER THE SECURITIES ACT. THE HOLDER OF
         THE SECURITY EVIDENCED HEREBY AGREES FOR THE BENEFIT OF
         THE COMPANY THAT SUCH SECURITY MAY BE RESOLD, PLEDGED OR
         OTHERWISE TRANSFERRED, ONLY (1) IN ACCORDANCE WITH AN
         EXEMPTION FROM THE REGISTRATION REQUIREMENTS OF THE
         SECURITIES ACT, OR (2) PURSUANT TO AN EFFECTIVE
         REGISTRATION STATEMENT AND, IN EACH CASE, IN ACCORDANCE
         WITH ANY APPLICABLE SECURITIES LAWS OF ANY STATE OF THE
         UNITED STATES OR ANY OTHER APPLICABLE JURISDICTION.

         NOBLE DRILLING (PAUL ROMANO) INC., a Delaware corporation (the
"Company"), for value received, hereby promises to pay to
_________________________ or registered assigns the principal sum of
_________________________ Dollars ($__________) on ___________, 20__, and to pay
interest (computed on the basis of a 360-day year of twelve 30-day months) on
the unpaid principal balance thereof from the date of this Note at the rate of
*1/_% per annum, monthly on the twentieth (20th) day of each month of each year,
commencing on _______________, until the principal amount hereof shall become
due and payable and to pay on demand interest on any overdue principal,
including any overdue prepayment of principal, and (to the extent permitted by
applicable law) on any applicable Make-Whole Amount or overdue installment of
interest, at a rate of interest per annum equal to the Default Rate; provided
that interest on this Note shall in no event exceed the maximum rate permitted
by applicable law, and this Note is expressly made subject to 12.5 of the
Indenture.

         Payments of principal, applicable Make-Whole Amount, if any, or other
amounts due hereon, and interest shall be made in any coin or currency of the
United States of America as at the time of payment is legal tender for the
payment of public and private debts in such manner and at such place as provided
in Section 4.6 of the Indenture.



- - -------------------------
         (1)The interest rate shall be the rate reported at 2:00 P.M. eastern 
time on the Business Day immediately before the Closing Date (as defined in the
Indenture) on the PX1 government page of the Bloomberg service as the yield to
maturity for the five year on-the-run U.S. Treasury security, plus (i) 64 basis
points, and (ii) the facility fee percentage set out in the letter agreement
between the Company and Banner Receivables Corporation dated September __, 1998.

                               -6-


<PAGE>   88



         This Note is one of an issue of Series B Senior Secured Notes of the
Company issued in an aggregate original principal amount limited to $16,837,500
under the Trust Indenture and Security Agreement of the Company (said indenture,
together with all agreements and indentures supplemental thereto being herein
called the "Indenture") dated as of ____________, 1998, with Chase Bank of
Texas, National Association as Trustee and is entitled to the benefits thereof.
Reference is hereby made to the Indenture for a description of certain rights,
obligations and duties of the parties thereto and for the meanings assigned to
terms used and not defined in this Note. As provided in the Indenture, this Note
is subject to optional prepayment. This Note is secured as set forth in the
Indenture and in the separate Note Purchase Agreements dated as of September __,
1998, between the Company and each of the Purchasers (listed on Schedule A
attached thereto).

         This Note is a registered Note and is transferable only by surrender
thereof at the agency of the Company maintained pursuant to Section 7.9 of the
Indenture, duly endorsed or accompanied by a written instrument of transfer duly
executed by the registered holder of this Note or its attorney duly authorized
in writing.

         Following any partial prepayment of this Note, this Note shall, prior
to any transfer hereof, be (a) made available to the Trustee for notation on the
prepayment schedule attached hereto of the amount of principal so prepaid or,
(b) at the option of the holder hereof and in lieu of the alternative in the
foregoing clause (a), held by the holder who shall make a notation of such
schedule of the amount of principal so prepaid. In case the entire principal
amount on this Note is prepaid or paid, this Note shall, upon written request
therefor by the Company, be surrendered promptly at the agency of the Company
maintained pursuant to Section 7.9 of the Indenture, for cancellation.

         In any case where the date of maturity of any interest, applicable
Make-Whole Amount, or other amounts due hereon, or principal owed with respect
to this Note or the date fixed for any prepayment (in whole or in part) of this
Note will not be a Business Day, then payment of such interest, applicable
Make-Whole Amount, or other amounts due hereon, or principal need not be made on
such date but may be made on the next succeeding Business Day with the same
force and effect as if made on the date of maturity or the date fixed for such
prepayment.

         Under certain circumstances, as specified in the Indenture, the
principal of this Note (together with interest accrued thereon and any
applicable Make-Whole Amount) may be declared due and payable in the manner and
with the effect provided in the Indenture.

         This Note and the Indenture are governed by, and shall be construed and
enforced in accordance with, the law of the State of New York applicable to
contracts made and to be performed entirely within such state and applicable
federal law.

Dated:
      --------------------------


ATTEST:                                       NOBLE DRILLING (PAUL ROMANO) INC.


                                              By
- - --------------------------------                -------------------------------


                               -7-


<PAGE>   89



Assistant Secretary                     Name:
                                             ----------------------------------
                                        Title:
                                              ---------------------------------
[CORPORATE SEAL]



         This is one of the Series B Notes described in the Indenture referred
to herein.

                               CHASE BANK OF TEXAS, NATIONAL ASSOCIATION,
                               as Trustee



                               By
                                 ----------------------------------------------
                                        Name:
                                             ----------------------------------
                                        Its:
                                            -----------------------------------


                               -8-


<PAGE>   90



                      PAYMENTS OF PRINCIPAL


<TABLE>
<CAPTION>


       Date of                                             Principal Amount
       Payment                 Amount Paid                 Remaining Unpaid                Authorized Signature
- - ----------------------  --------------------------  ------------------------------  -----------------------------------
<S>                     <C>                         <C>                             <C>



</TABLE>






















                               -9-


<PAGE>   91



                         ASSIGNMENT FORM

         To assign this Note, fill in the form below: (I) or (we) assign and
transfer this Note to


- - --------------------------------------------------------------------------------
                  (Insert assignee's soc. sec. or tax I.D. no.)








- - --------------------------------------------------------------------------------
              (Print or type assignee's name, address and zip code)

and irrevocably appoint____________________________________________________
to transfer this Note on the books of the Company. The agent may substitute
another to act for him.



Date:

                              Your Signature:
                                             -----------------------------------
                              (Sign exactly as your name appears on the face of
                               this Note)

                              Signature Guarantee:
                                                  ------------------------------



                                      -10-






<PAGE>   1
                                                                     EXHIBIT 4.3



===============================================================================



                              FIRST NAVAL MORTGAGE


                                     Made by

                        Noble Drilling (Paul Romano) Inc.

                                   In Favor of


         Chase Bank of Texas, National Association, as Indenture Trustee


                                       on

                                Noble Paul Romano


                        Dated as of ______________, 1998






================================================================================





<PAGE>   2



                           First Naval Mortgage
                           Mortgagor:        Noble Drilling (Paul Romano) Inc.
                                             10370 Richmond Avenue
                                             Suite 581
                                             Houston, Texas  77042

                           Mortgagor's Interest in the Vessel:  100%
                           Mortgagee:        Chase Bank of Texas, National
                                             Association
                                             600 Travis, Suite 1150
                                             11th Floor
                                             Houston, Texas 77002

                           Amount of Mortgage:  $112,250,000.00
                           Maturity Date: ____________________



         THIS FIRST NAVAL MORTGAGE dated as of the ___ day of ___________, 1998
(as amended, supplemented or otherwise modified from time to time, the
"Mortgage") is made and given by Noble Drilling (Paul Romano) Inc., a Delaware
corporation (the "Mortgagor"), whose address is set forth above, to Chase Bank
of Texas, National Association, as Indenture Trustee for any and all future
holders of the Notes (as such term is hereinafter defined), whose address is set
forth above (hereinafter referred to, together with its successors and assigns,
as the "Mortgagee").

                                    RECITALS

         A. Of even date herewith, Mortgagor and Chase Bank of Texas, National
Association have entered into that certain Trust Indenture and Security
Agreement (as the same may be amended, supplemented, restated or otherwise
modified from time to time, the "Trust Indenture"). Pursuant to the terms and
conditions contained in the Trust Indenture, Mortgagor entered into those
certain Note Purchase Agreements dated September 24, 1998 (the "Note Purchase
Agreements") wherein certain lenders (the "Lenders") have agreed to make a term
loan to Mortgagor in the aggregate principal amount of $112,250,000.00, as
evidenced by those certain Series A Senior Secured Notes in the original
principal amount of $95,412,500 and those certain Series B Senior Secured Notes
in the original principal amount of $16,837,500 (the promissory notes referred
to above, as the same may be amended, supplemented, restated or otherwise
modified from time to time, being herein collectively referred to as the
"Notes"). The Series A Senior Secured Notes are payable in installments of
interest at ____% per annum (based on a 360 day year of twelve thirty day
months) and principal in accordance with the provisions of Schedule A-1 attached
hereto, and the Series B Senior Secured Notes provide for the monthly payment of
interest at ____% per annum (based on a 360 day year of twelve thirty day
months) with principal payable at maturity. Copies of the Trust Indenture, Note
Purchase Agreements and the Notes are on file at the offices of Mortgagee at the
address above, where they may be consulted for the full text thereof. The Trust
Indenture, Note Purchase Agreements and the Notes, by reference, are
incorporated herein.



<PAGE>   3



         B. Mortgagee has requested pursuant to the terms of the Trust Indenture
that Mortgagor execute and deliver this Mortgage, and Mortgagor has agreed to
enter into this Mortgage on the vessel "Noble Paul Romano", duly documented in
the name of Mortgagor under the laws and flag of the Republic of Panama Patente
No. 27264-HT, bearing international call letters HP-9320, of 13,665 gross
tonnage, 4,099 net tonnage, 93.68 meters in length, 100.05 meters in width,
39.62 meters in depth, and title registered at Filing Card N-21215, Roll 61088,
Frame 0012 on July 24, 1998 (together with the Equipment, as defined below, the
"Vessel").

         C. Now, therefore, in consideration of the premises and of other
valuable consideration, receipt of which is hereby acknowledged, Mortgagor
hereby agrees as follows:

                                    ARTICLE I

                         GRANTING CLAUSE AND DEFINITIONS

         Section 1.1 Granting Clause. To secure the full and timely payment of
and the full and timely performance and discharge of the Obligations (as
hereinafter defined), Mortgagor hereby Mortgages and executes and constitutes a
First Naval Mortgage in accordance with the provisions of Chapter V Title IV of
Book Second of the Code of Commerce and other pertinent legislation of the
Republic of Panama in favor of Mortgagee, its successors and assigns, upon the
whole of the Vessel, together with its boilers, engines, machinery, masts,
spars, sails, riggings, boats, anchors, cables, chains, tackle, tools, pumps and
pumping equipment, apparel, furniture, fittings and equipment, spare parts,
capstans, outfit, tanks and tank batteries, fixtures, valves, fittings, draw
works, machinery and parts, meters, apparatus, equipment, appliances, tools,
implements, cables, wires, derricks, towers, casing, tubing and rods, and all
other appurtenances thereunto appertaining or belonging, whether now owned or
hereafter acquired, whether or not on board the Vessel, and all additions,
improvements, renewals and replacements hereafter made in or to the Vessel or
any part thereof, or in or to any said appurtenances (the "Equipment").

         TO HAVE AND TO HOLD all and singular the above mortgaged and described
property unto Mortgagee, its successors and assigns, forever upon the terms
herein set forth;

         PROVIDED, HOWEVER, and these presents are on the condition that if the
Obligations are paid and performed in accordance with the terms thereof and this
Mortgage, then these presents and the estates and rights hereunder shall cease,
terminate and be void, otherwise to be and remain in full force and effect.

         Section 1.2 Definitions. As used in this Mortgage, the terms "Lenders",
"Mortgage", "Mortgagor", "Mortgagee", "Note Purchase Agreements", "Notes",
"Trust Indenture", and "Vessel" shall have the meanings assigned to them in the
recitals hereto. Any capitalized term used in this Mortgage and not defined
herein shall have the meaning assigned to such term in the Trust Indenture. As
used herein, the following terms shall have the following meanings:

         "Dollars" or "$" means the lawful currency of the United States of
America.


                                       -2-


<PAGE>   4



         "Equipment" shall have the meaning set forth in Section 1.1 hereof.

         "Event of Loss" shall mean any one of the following events: (i) actual
total loss or destruction of the Vessel or any accident, occurrence or event
resulting in a constructive total loss or an agreed or compromised total loss of
the Vessel; or (ii) substantial damage to the Vessel, the repair of which is
uneconomical as determined in good faith by the Mortgagor, including, but not
limited to, any event pursuant to which insurance proceeds are available which
are not applied to repair the Vessel or any other event resulting for any reason
whatsoever in the Vessel being permanently rendered unfit for normal use; or
(iii) the condemnation, confiscation, requisition, seizure, detention,
forfeiture, purchase or other taking of title to or use of the Vessel (unless in
the case of a requisition, seizure, detention, or forfeiture, such action is
revoked within thirty (30) days or such shorter period within which SDDI may
terminate the Shell Contract as an event of force majeure) except the
requisition of the use of the Vessel by any Governmental Authority of the United
States or any state thereof on a basis not involving requisition of title to or
seizure or forfeiture of the Vessel.

         "Event of Default" shall have the meaning set forth in Section 3.1
hereof.

         "Notice of Entitlement to Terminate" shall have the meaning set forth
in the Performance Agreement.

         "Obligations" shall mean (i) the payment when due of all indebtedness
evidenced by the Notes in the aggregate principal sum of $112,250,000.00 USD,
interest (including post-petition interest) as set forth in the Notes and the
Trust Indenture, and premiums (including Make-Whole Amount), penalties and late
charges thereon, (ii) all other indebtedness and other sums (including, without
limitation, all expenses, attorneys' fees, other fees, indemnifications,
reimbursements, damages, other monetary liabilities, and other charges) that may
and shall become due hereunder or under the Notes, the Trust Indenture or the
other Credit Documents, and (iii) any and all renewals, modifications,
amendments, extensions for any period, supplements or restatements of any of the
foregoing.

         "Master's Wages" shall have the meaning set forth in Section 2.6
hereof.

                                   ARTICLE II

                    REPRESENTATIONS, WARRANTIES AND COVENANTS

         In order to induce Mortgagee to accept this Mortgage as collateral
security for the Obligations, Mortgagor represents and warrants to Mortgagee and
covenants and agrees with Mortgagee that:

         Section 2.1 Legal Existence; Citizenship and Authorization. Mortgagor
is a corporation duly organized and validly existing under the laws of the state
of Delaware; and except as permitted by the Trust Indenture, shall maintain its
corporate existence during the term of this Mortgage; and is duly qualified to
engage in the trade in which the Vessel operates. Mortgagor is duly authorized
to mortgage the Vessel, and all action necessary and required by law for the
execution and delivery of

                                       -3-


<PAGE>   5



this Mortgage has been duly and effectively taken by it, and this Mortgage is
the valid and enforceable obligation of Mortgagor. All necessary consents and
approvals of any Governmental Authority or any other entity to the entering into
and performance of this Mortgage have been duly obtained or given and the
entering into and performance of this Mortgage does not and will not contravene
the terms of or constitute a default under (with or without giving of notice or
lapse of time or both) any material agreement, instrument or document to which
Mortgagor is a party or by which it or its properties are bound or affected
after giving effect to the use of the proceeds of the Notes.

         Section 2.2 Ownership of Vessel; Warranty and Defense of Title.
Mortgagor is the sole owner of the whole of the Vessel and is lawfully possessed
of the whole of the Vessel, free from any Lien whatsoever other than the Lien of
this Mortgage, and the Liens permitted by Section 2.6 hereof not in excess of
$5,000,000, and Mortgagor will warrant and defend the title to and possession of
the Vessel and every part thereof for the benefit of Mortgagee against the
claims and demands of all other Persons whomsoever, subject to the Liens and
other matters permitted by the Trust Indenture or this Mortgage.

         Section 2.3  Compliance with Laws.

                  (a) Documentation. The Vessel is, and during the term of this
Mortgage shall continue to be, duly and lawfully registered under the laws and
flag of the Republic of Panama, and Mortgagor will comply with and satisfy all
of the provisions of the laws of the Republic of Panama in order that the Vessel
shall continue to be documented pursuant to the laws of the Republic of Panama
as a vessel of the Republic of Panama under the Republic of Panama flag.

                  (b) Laws, Treaties and Conventions. The Vessel shall, and
Mortgagor covenants that it will in the operation of the Vessel, at all times
comply in all material respects with all applicable laws, treaties and
conventions and rules and regulations issued thereunder, and shall have on board
as and when required thereby valid certificates showing compliance therewith,
except when (i) the use or title of the Vessel has been taken, requisitioned or
chartered by any Governmental Authority, (ii) there has been an Event of Loss,
or (iii) there has been any other partial loss or damage with respect to the
Vessel and Mortgagor shall be in compliance with its obligations under Sections
4.2(c) and 7.3(c) of the Trust Indenture.

         Section 2.4 Operation of Vessel. Mortgagor will not (except during any
period when the use or title to the Vessel has been taken, requisitioned or
chartered by any Governmental Authority) cause or permit the Vessel to be
operated in any manner contrary to applicable law or regulation, will not
abandon the Vessel in any non-United States port (unless an Event of Loss has
occurred as to the Vessel or the safety or welfare of Mortgagor's employees on
the Vessel is endangered), will not engage in any unlawful trade, violate any
law or carry any cargo that will expose the Vessel to penalty, forfeiture or
capture and will not do, or suffer or permit to be done, anything which can or
may injuriously affect the documentation of the Vessel under the existing laws
and regulations of the Republic of Panama or the United States of America.
Without limiting the generality of the foregoing, the Mortgagor shall not
charter the Vessel to, or permit the Vessel to serve under any contract with, a
person included within the definition of (i) "national" of a "designated foreign

                                       -4-


<PAGE>   6



country," or "specially designated national" of a "designated foreign county,"
in the Foreign Assets Control Regulations or the Cuban Assets Control
Regulations of the United States Treasury Department, 31 C.F.R. Parts 500 and
515, in each case as amended, (ii) "Government of Libya," "entity of the
Government of Libya" or "Libyan entity" in the Libyan Sanctions Regulations of
the United States Treasury Department, 31 C.F.R. Part 550, as amended, or (iii)
"Government of Iraq," "entity of the Government of Iraq" or "Iraqi Government
entity" in the Iraqi Sanctions Regulations, 31 C.F.R. Part 575, as amended, all
within the meaning of said Regulations or of any regulations, interpretations or
rulings issued thereunder, or engage in any transaction that violates any
provision of said Regulations or that violates any provision of the Iranian
Transactions Regulations, 31 C.F.R. Part 560, as amended, the Transaction
Control Regulations, 31 C.F.R. Part 505, as amended, the Foreign Assets Control
Regulations, 31 C.F.R. Part 500, as amended, or Executive Orders 12810 and
12831, or call at a Cuban port to load or discharge cargo or to effect repairs
on the Vessel. Furthermore, the Mortgagor shall keep the Vessel at all times in
United States territorial waters in the Gulf of Mexico or in the Gulf of Mexico
on or above the outer Continental Shelf of the United States and as set forth in
Section 1 of the Drilling Order.

         Section 2.5 Claims, Taxes, Fees. etc. Mortgagor will pay and discharge
or cause to be paid and discharged prior to delinquency, all claims against, and
fees, taxes, assessments, governmental charges, fines and penalties imposed on,
the Vessel, its cargoes or any income therefrom; provided, that nothing in this
Section 2.5 shall require Mortgagor to pay any such claim, fee, tax, assessment,
governmental charge, fine or penalty so long as the validity thereof shall be
contested by it in good faith and by appropriate proceedings, and, provided,
further, that such contest shall not subject the Vessel, or any part thereof, to
arrest, attachment, forfeiture or loss or subject the Mortgagee or any Lender to
the risk of any civil or criminal liability.

         Section 2.6 Liens. Neither Mortgagor, any charterer or subcharterer,
the master of the Vessel nor any other Person has or shall have any right, power
or authority to create, incur or permit to be placed or imposed or continued
upon the Vessel and Mortgagor shall not permit to exist on the Vessel any Lien
whatsoever other than the Lien of this Mortgage and the following:

                  (i) Liens for wages of the crew (including wages of a master
to the extent provided by law, "Master's Wages"), general average and salvage
(including contract salvage) which shall not have been due and payable for
forty-five (45) days after termination of a voyage or which shall then be
contested by Mortgagor in good faith and by appropriate proceedings; provided
that such contest shall not subject the Vessel to arrest, attachment, forfeiture
or loss or subject the Mortgagee or any Lender to the risk of any civil or
criminal liability;

                  (ii) Liens for wages of the crew (including Master's Wages)
and salvage (including contract salvage) which are either unclaimed or covered
by insurance;

                  (iii) Liens incident to current operations of Mortgagor in the
ordinary course of business (except for wages of the crew including Master's
Wages and salvage) or liens covered by insurance and any deductible applicable
thereto;


                                       -5-
 

<PAGE>   7



                  (iv) Liens for repairs the payment for which is either not
overdue or is being contested by Mortgagor in good faith and by appropriate
proceedings; provided that such contest shall not subject the Vessel to arrest,
attachment, forfeiture or loss or subject the Mortgagee or any Lender to risk of
any civil or criminal liability;

                  (v) Liens arising by reason of an actual or constructive total
loss or an agreed or compromised total loss of the Vessel;

                  (vi) Liens permitted by the Trust Indenture;

provided that the Liens stated to be permitted by the foregoing subparagraphs
(i) through (iv) shall, unless they constitute a Lien for damage arising out of
tort, for wages of a stevedore when employed directly by Mortgagor, master,
ship's husband, or agent, for wages of the crew (including Master's Wages), for
general average, or for salvage (including contract salvage), be permitted only
to the extent such Liens are either accrued but not yet due or are subordinate
to the Lien of this Mortgage. Nothing contained in this Section 2.6 constitutes
a waiver by Mortgagee of Mortgagee's preferred status. If any such Lien is
placed on the Vessel which is not subordinate to the Lien of this Mortgage,
Mortgagor will promptly after becoming aware of such Lien notify Mortgagee.

         Section 2.7 Notice of Mortgage. Mortgagor will at all times carry on
board the Vessel (with the ship's papers) a certified copy of this Mortgage and
any amendments and supplements hereto and any assignments hereof, and will
exhibit or cause to be exhibited the same to any Person having business with the
Vessel which might give rise to a Lien upon the Vessel or to the sale,
conveyance, mortgage or lease thereof and, on demand, to any representative of
Mortgagee. Mortgagor will also place and keep prominently displayed on the
Vessel a framed printed notice in plain type of such size that the paragraph of
reading matter shall cover a space of not less than six inches wide by nine
inches high (or such other dimensions as may be required by law) reading as
follows:

                               "NOTICE OF MORTGAGE

         This Vessel is owned by Noble Drilling (Paul Romano) Inc. and is
         subject to a First Naval Mortgage in favor of Chase Bank of Texas,
         National Association, as Indenture Trustee, as Mortgagee, a certified
         copy of which Mortgage is kept with this Vessel's papers. Under the
         terms of said Mortgage, neither the owner, any charterer or
         subcharterer, the master of this Vessel nor any other person has any
         right, power or authority to create, incur or permit to be placed or
         imposed upon this Vessel any lien whatsoever other than the lien of
         said Mortgage, liens for wages, general average or salvage, and certain
         other liens permitted by the provisions of said Mortgage."

         Section 2.8 Libel or Attachment. If a libel or any similar legal action
is filed against the Vessel or if the Vessel shall be attached, levied upon or
taken into custody by virtue of any proceeding in any court or tribunal,
Mortgagor will promptly notify Mortgagee thereof by telegram, cable or
facsimile, confirmed by letter addressed to Mortgagee, and within thirty (30)
days after any such libel (other than (i) a libel involving claims less than
$2,500,000 or (ii) a libel involving claims equal to or in excess of $2,500,000
and where the Mortgagee has not received a reservation of rights

                                       -6-
 

<PAGE>   8



notice, or similar communication from its insurance carrier contesting or
denying coverage), levy, attachment or taking into custody, Mortgagor will cause
the Vessel to be released and will promptly notify Mortgagee of such release in
the manner aforesaid. In the event that the Vessel shall not be released within
fifteen (15) days after such libel, levy, attachment or action to take the
Vessel into custody, or at any time Mortgagee receives a Notice of Entitlement
to Terminate with respect to any such libel, levy, attachment, or action to take
the Vessel into custody, Mortgagor does hereby authorize and empower Mortgagee,
in the name of Mortgagor, or its successor or assigns, to apply for and receive
possession of and to take possession of the Vessel with all the rights and
powers that Mortgagor, or its successors or assigns, might have, possess or
exercise in any such event; and this power of attorney shall be irrevocable and
may be exercised not only by Mortgagee hereinabove named but also by any one
such appointee or the appointees of Mortgagee, with full power of substitution,
to the same extent as if the said appointee or appointees had been named as one
of the attorneys above named by express designation.

         Section 2.9 Maintenance of Vessel. Except as to such period as (i) the
use or title of the Vessel has been taken, requisitioned or chartered by a
Governmental Authority, (ii) there has been actual or constructive total loss or
an agreed or compromised total loss of the Vessel, or (iii) there has been any
other partial loss or damage with respect to the Vessel and Mortgagor shall be
in compliance with its obligations under Sections 4.2(c) and 7.3(c) of the Trust
Indenture, Mortgagor will, at all times and without cost or expense to
Mortgagee, maintain and preserve, or cause to be maintained and preserved, the
Vessel in good running order and repair, so that the Vessel shall be tight,
staunch, strong and well and sufficiently tackled, appareled, furnished,
equipped and in every respect seaworthy and in first class order and operating
condition and in full compliance with and able to perform all operations under
the Shell Contract; and otherwise in compliance with the provisions of the Trust
Indenture.

         Section 2.10 Inspection. Weather permitting, Mortgagor will permit
Mortgagee, any Lender or its representative to visit and inspect the Vessel,
under the Mortgagor's guidance, to examine all of its books of account, records,
reports and other papers, to make copies and extracts therefrom and to discuss
its affairs, finances and accounts with its officers, employees, and independent
public accountants (and by this provision the Mortgagor authorizes said
accountants to discuss with Mortgagee or any Lender the finances and affairs of
the Mortgagor) all at such reasonable time, upon reasonable notice and as often
as may be reasonably requested; provided that the Mortgagor shall not be
required to pay or reimburse any Lender for expenses which such Lender may incur
in connection with any such visitation or inspection, except that if such
visitation or inspection is made during any period when an Indenture Default or
an Indenture Event of Default shall have occurred and be continuing, the
Mortgagor agrees to reimburse such Lender for all such expenses promptly upon
demand.

         Section 2.11 Sale or Other Disposition of Vessel. Except as allowed in
the Trust Indenture, Mortgagor will not sell, mortgage, transfer or in any other
way dispose of all or any part of the Vessel without the prior written consent
of Mortgagee.

         Section 2.12 Notice. Mortgagor shall notify the Mortgagee forthwith by
facsimile thereafter confirmed by letter of:

                                       -7-
 

<PAGE>   9



         (a) any casualty event in excess of $250,000 with respect to the
Vessel; and

         (b) any occurrence in respect of the Vessel that is or is likely, by
the passing of time or otherwise, to become an Event of Loss; and

         (c) any material requirement or recommendation made by any insurer or
classification society or by any competent authority which is not complied with
within a reasonable time; and

         (d) any arrest, governmental detention, or attachment of the Vessel or
the assertion or purported assertion of any lien against the Vessel; and

         (e) any intended dry docking of the Vessel, as to which the Mortgagor
shall give the Mortgagee 30 days' prior notice, provided, that in the event of
any emergency dry docking of the Vessel, the Mortgagor shall promptly notify the
Mortgagee; and

         (f) any intended deactivation or lay-up of the Vessel.

         Section 2.13  Insurance.

                  (a) All Risk Property Insurance. Mortgagor shall, at its own
expense, keep the Vessel insured, in lawful money of the United States, against
all such risks (including without limitation, hull and machinery/increased
value, protection and indemnity risk, pollution liability, war risks and, when
laid up, port risk insurance as well as such excess policies over and above
protection and indemnity and general liability coverage which shall represent
collective limits of not less than $400,000,000), in such form and with such
insurance companies or underwriters as required under Section 2.13(f) as shall
be at least as protective as insurance maintained by prudent owners of vessels
and equipment similar to the Vessel, engaged in international contract offshore
oil and gas operations, and in any event all as reasonably acceptable to
Mortgagee and in compliance with the Shell Contract. Without limiting the
generality of the foregoing, with respect to hull and machinery/increased value
insurance, including war risk, the Mortgagor shall insure the Vessel for an
amount which is at least equal to the Obligations plus $250,000. Such insurance
shall cover marine and war risk perils, on hull and machinery, with per
occurrence deductibles not in excess of $250,000 and shall be maintained in the
broadest forms available in the American and British insurance markets. The
Mortgagor shall maintain protection and indemnity (or its equivalent) insurance,
including war risk protection and indemnity (or its equivalent) coverage in an
amount not less than $400,000,000. The Mortgagor shall maintain coverage against
pollution liability in an amount not less than $400,000,000 (or such greater
amount as may be required from time to time under Oil Pollution Act of 1990 or
other environmental laws). All of the foregoing insurance shall have a per
occurrence deductible not to exceed $250,000 and be placed through such
underwriters or associations reasonably acceptable to the Mortgagee. The Vessel
shall not operate in or proceed into any area then excluded by trading
warranties under its marine or war risk policies (including protection indemnity
or its equivalent) without satisfying the conditions of the relevant policies,
evidence of which shall be furnished to the Mortgagee.


                                       -8-
 

<PAGE>   10



                  (b) Liability; Workers' Compensation. Mortgagor shall maintain
at all times such worker's compensation, employer's liability, and longshoreman
and harbor worker's insurance as shall be required by applicable law. Mortgagor
shall also maintain public liability insurance together with umbrella liability
coverage as insured against by prudent owners of vessels and equipment similar
to the Vessel. Such policies shall provide that any loss under such insurance
may be paid directly to the entity to whom any liability covered by such
policies has been incurred.

                  (c) Payment Provisions. All payments made under policies of
insurance maintained under this Section shall be applied as set forth in Section
4.2 of the Trust Indenture.

                  (d) Constructive Total Loss. In the case of an Event of Loss
that is a constructive total loss of the Vessel, Mortgagee shall have the right
(but only with prior written consent of Mortgagor unless an Indenture Event of
Default has occurred and is continuing) to join in Mortgagor's claim for a
constructive total loss of the Vessel, and if both (i) such claims are accepted
by all underwriters under all policies then in force as to the Vessel and (ii)
payment in full is made in cash under such policies to Mortgagee in an amount at
least equal to the then outstanding amount of the Obligations, then Mortgagee
shall have the right to abandon the Vessel to the underwriters under such
policies, free from the Lien of this Mortgage.

                  (e) Agreed Total Loss. Mortgagee shall not have the right to
enter into an agreement or compromise providing for an agreed or compromised
total loss of the Vessel without the prior written consent of Mortgagor unless
an Indenture Event of Default has occurred and is continuing. If Mortgagor shall
have given its prior consent thereto, or an Indenture Event of Default has
occurred and is continuing, Mortgagee shall have the right in its discretion to
enter into an agreement or compromise providing for an agreed or compromised
total loss of the Vessel, provided the same is agreed to by underwriters under
all applicable policies.

                  (f) Insurers. All insurance required under this Section 2.13
shall be placed and kept with such insurance companies, Lloyd's Syndicates,
underwriters' associations, clubs or underwriting funds as are reputable,
generally recognized within the industry, and (i) in the case of hull and
machinery insurance, rated by either Standard & Poors Rating Services, a
division of the McGraw Hill Companies, Inc. ("S&P") or Moody's Investors
Services, Inc. ("Moody's) with at least the equivalent to an S&P rating of BBB
(and with at least 75% of the companies, determined by dollar amount of policy
coverage, rated by S&P or Moody's with at least the equivalent to an S&P rating
of A) or, if not rated by S&P or Moody's then rated "excellent" or better by
A.M. Best, and (ii) in the case of protection and indemnity risk insurance,
rated by either S&P or Moody's with at least the equivalent to an S&P rating of
BBB.

                  (g) Taking by United States. During the continuance of a
taking, requisition or charter of the use of the Vessel by any governmental body
of the United States of America, the provisions of this Section 2.13 shall be
deemed to have been complied with in all respects as to the Vessel if the United
States Government or any such governmental body shall have agreed (i) to
reimburse Mortgagee and Mortgagor for loss or damage resulting from the risks
indicated in paragraphs (a) and (b) of this Section 2.13, or (ii) that Mortgagee
and Mortgagor shall be entitled to just compensation therefor. In the event of
any taking, requisition, charter or loss of the Vessel

                                       -9-
 

<PAGE>   11



contemplated by this paragraph (g), Mortgagor shall promptly furnish to
Mortgagee a sworn certificate of an officer of Mortgagor stating that such
taking, requisition, charter or loss has occurred and, if there shall have been
a taking, requisition or charter of the Vessel, that the United States
Government or governmental body has agreed (i) to reimburse Mortgagor for loss
or damage resulting from the risks indicated in the above-mentioned paragraphs
(a) and (b) or (ii) that Mortgagor or Mortgagee, as the case may be, is entitled
to just compensation therefor.

                  (h) Mortgage Provisions. All insurance required under this
Section 2.13 shall be taken out in the name of Mortgagor or on its behalf by an
Affiliate of Mortgagor. Mortgagee and each Lender shall be named as an
additional insured under all liability policies (other than workers'
compensation and similar insurance), and Mortgagee shall be named as the sole
loss payee under all physical damage policies with respect to the Vessel. All
policies for such insurance shall also provide that (i) there shall be no
recourse against Mortgagee (or its assignee) or any Lender for the payment of
premiums or commissions, (ii) if such policies provide for the payment of club
calls, assessments or advances, there shall be no recourse against Mortgagee (or
its assignee) or any Lender for the payment thereof. All policies shall provide
that the insurers shall provide to Mortgagee (or its assignee) and each Lender
30 days prior notice of any material change in the coverage of such insurance as
well as ten (10) days prior written notice of any cancellation of such insurance
in the event of non-payment of premiums and seven (7) days prior written notice
of any cancellation of such insurance for war risk.

                  (i) Compliance. Mortgagor shall not do any act, nor permit any
act to be done, whereby any insurance required by this Section 2.13 shall or may
be suspended, impaired or defeated, or permit the Vessel to engage in any
voyage, to engage in any activity or to carry any cargo not permitted under the
policies of insurance then in effect without first procuring comparable
insurance for such voyage, activity or the carriage of such cargo.

                  (j) Policies. Mortgagor, upon execution of this Mortgage,
shall deliver to Mortgagee certificates of insurance, evidencing the insurance
maintained under this Section 2.13. Mortgagor, upon the request of Mortgagee,
will promptly deliver to Mortgagee true copies of such policies.

                  (k) Opinion and Certificates. At such times as Mortgagee may
reasonably request, Mortgagor shall furnish or cause to be furnished to
Mortgagee a detailed certificate or opinion (signed by a reputable insurance
broker) as to the insurance maintained by Mortgagor pursuant to this Section
2.13, specifying the respective policies of insurance covering the same and
attaching certificates of confirmation evidencing the same and stating with
regard to the insurance maintained by Mortgagor pursuant to this Section 2.13
the amounts, deductibles, and the risks against which such insurance is issued.

                  (l) Obligation to Collect. Mortgagor shall, at no cost or
expense to Mortgagee, have the duty and responsibility to make all proofs of
loss and take any and all other steps necessary as a prudent owner or as
reasonably directed by Mortgagee to effect collections from underwriters for any
loss under any insurance on or in respect of the Vessel or the operation
thereof.


                                      -10-
 

<PAGE>   12



         Section 2.14 Change of Flag, Port of Documentation or Name. Mortgagor
will not change or transfer the flag, port of documentation or the name of the
Vessel, except in strict compliance with Section 7.3 of the Trust Indenture.


                                   ARTICLE III

                        REMEDIES; APPLICATION OF PROCEEDS

         Section 3.1 Sale, Etc. If an Event of Default shall have occurred and
be continuing, Mortgagee may, to the fullest extent permitted by and in
accordance with applicable law:

         (a) exercise all the rights and remedies in foreclosure and otherwise
given to mortgagees by the laws of the Republic of Panama, and by the applicable
laws of any other applicable jurisdiction;

         (b) bring suit at law, in equity or in admiralty or initiate and
prosecute such other judicial, extrajudicial, or administrative proceedings as
it may consider appropriate to recover any and all sums due, or declared due, in
respect of the Obligations, with the right to enforce payment of said sums
against any assets of Mortgagor, whether they are covered by this Mortgage or
otherwise;

         (c) to the extent permitted by and in accordance with any applicable
law, take possession of the Vessel, with or without legal proceedings, at any
place where it may be found, and Mortgagor or any Person in possession of the
Vessel, forthwith upon request by Mortgagee, as mortgage creditor, shall deliver
possession to Mortgagee on demand of Mortgagee, and Mortgagee shall have the
right, subject to applicable law, without being responsible for loss or damage
to lay up, hold, charter, lease, operate or otherwise use the Vessel for such
period and under such conditions as it may deem most expedient for its interest,
accounting only for net profits, if any, arising from such use and charging
against all receipts from such use or from the sale of the Vessel by court
proceedings or pursuant to subsection (d) below, all costs, expenses, charges,
damages or losses by reason of such use; and if at any time Mortgagee shall
avail itself of the right herein given to it to take the Vessel and shall take
it, Mortgagee shall have the right to dock the Vessel at any dock, pier or other
premises owned or leased by Mortgagor without charge, or at any other place at
the cost and expense of Mortgagor;

         (d) to the extent permitted by and in accordance with any applicable
law, sell the Vessel at public or private sale, by sealed bids or otherwise, on
such terms and conditions as Mortgagee deems best, free of any claim, lien,
commitment or encumbrance, regardless of the nature thereof, in favor of
Mortgagor and, except as provided by law, any other person, upon advance notice
of ten (10) consecutive days published in any newspaper authorized to publish
legal notices of that kind in the port of registry and the place of sale of the
Vessel and by sending notice of such sale at least twenty (20) days prior to the
date fixed for such sale, by telegraph, cable, telefax or telex, confirmed by
mail, to Mortgagor. In the event that the Vessel shall be offered for sale by
private sale, no newspaper publication of notice shall be required, nor notice
of adjournment of sale. Sale may be held at such place and at such time as
Mortgagee by notice may have specified, or may be adjourned

                      
                                      -11-
 

<PAGE>   13



by Mortgagee from time to time by announcement at the time and place appointed
for such sale or for such adjourned sale, and without further notice or
publication Mortgagee may make any such sale at the time and place to which the
same shall be so adjourned; and any sale may be conducted without bringing the
Vessel to the place designated for such sale and in such manner as Mortgagee may
deem to be for its best advantage, and Mortgagee may become the purchaser at any
public sale, and shall have the right to credit on the purchase price any and
all sums of money due hereunder or under any other Credit Document. Without
limiting the generality of the foregoing, Mortgagee shall be entitled to
exercise all the rights and remedies available to it under Articles 1527 and
1527-A of the Code of Commerce of the Republic of Panama;

         (e) manage, insure, maintain and repair the Vessel and charter, employ,
sail or lay up the Vessel in such manner, upon such terms and for such period as
the Mortgagee deems reasonably expedient; and for the purposes aforesaid the
Mortgagee shall be entitled to do all acts and things reasonably incidental or
conducive thereto and in particular to enter into such arrangements respecting
such Vessel, and the insurance, management, maintenance, repair, classification,
chartering and employment of such Vessel, in all respects as if the Mortgagee
were the owner of such Vessel and without being responsible for any loss thereby
incurred;

         (f) recover from the Mortgagor on demand any liabilities, losses and
reasonable expenses as may be incurred by the Mortgagee in or about the exercise
of the power vested in the Mortgagee hereunder;

         (g) generally, recover from the Mortgagor on demand any liabilities,
losses and reasonable expenses incurred by the Mortgagee in or about or
incidental to the exercise by it of any of the powers aforesaid;

         (h) not be required to have the Vessel marshaled (upon any sale of the
Vessel) or be required to realize on any other collateral prior to its
realization on the Vessel; and

         (i) exercise any other rights it may have under applicable law or any
other Credit Document.

         As used in this Mortgage, "Event of Default" shall mean the occurrence
of an Indenture Event of Default under the Trust Indenture.

         Section 3.2 Finality of Sale. A sale of the Vessel made in pursuance of
this Mortgage, whether under the power of sale hereby granted or any judicial
proceedings, shall operate to divest all right, title and interest of any nature
whatsoever of Mortgagor therein and thereto, and shall bar Mortgagor, its
successors and assigns, and all Persons claiming by, through or under them. No
purchaser shall be bound to inquire whether notice has been given or whether any
default has occurred, or as to the propriety of the sale, or as to application
of the proceeds thereof.

         Section 3.3 Powers and Rights of Mortgagee Upon Notice of Default.
During the occurrence and continuance of an Event of Default, Mortgagee shall
have the following powers and rights:


                                      -12-
 

<PAGE>   14



                  (a) Sale. Mortgagor does hereby irrevocably appoint Mortgagee
and its successors and assigns the true and lawful attorney of Mortgagor, in its
name and stead, for the purpose of Sections 3.1 and 3.2, to make all necessary
transfers of the Vessel, and for that purpose Mortgagee shall execute all
necessary instruments of assignment and transfer (including bills of sale),
Mortgagor hereby ratifying and confirming all that its said attorney shall
lawfully do by virtue hereof. Nevertheless, Mortgagor shall, if so requested by
Mortgagee, ratify and confirm any sale of the Vessel by executing and delivering
to the purchaser thereof such proper bills of sale, conveyances, instruments of
transfer and releases as may be designated in such request.

                  (b) Revenues and proceeds of Vessel; Prior Liens.

                           (i) Mortgagee is hereby irrevocably appointed
         attorney-in-fact of Mortgagor, with the power, among other things, so
         long as an Event of Default has occurred and is continuing, in the name
         of Mortgagor to demand, collect, receive, compromise and sue for, so
         far as may be permitted by law, all freights, hire, earnings, issues,
         revenues, income and profits of the Vessel, and all amounts due from
         underwriters under any insurance thereon as payment of losses or as
         return premiums or otherwise, salvage awards and recoveries, recoveries
         in general average or otherwise, and all other sums due or to become
         due in respect of the Vessel or in respect of any insurance thereon
         from any person whomsoever, and to make, give and execute in the name
         of Mortgagor acquittances, receipts, releases or other discharges for
         the same, whether under seal or otherwise, and to endorse and accept in
         the name of Mortgagor all checks, notes, drafts, warrants, agreements
         and all other instruments in writing with respect to the foregoing,
         Mortgagor hereby confirming and ratifying the same.

                           (ii) So long as an Event of Default has occurred and
         is continuing, Mortgagee is hereby irrevocably authorized to pay or
         furnish indemnity in the proper amounts against any Liens which have or
         may (in the reasonable opinion of Mortgagee) have priority over the
         Lien of this Mortgage and which are not permitted under this Mortgage
         or the Trust Indenture.

                  (c) Additional Rights. Mortgagor covenants and agrees that in
addition to any and all other rights, powers and remedies elsewhere in this
Mortgage granted to and conferred upon Mortgagee, Mortgagee in any suit to
enforce any of its rights, powers or remedies shall be entitled as a matter of
right and not as a matter of discretion (i) to seek the appointment of a
receiver or receivers of the Vessel and any receiver or receivers so appointed
shall have full right and power to use and operate the Vessel as shall be
ordered by any court having jurisdiction, (ii) to a decree ordering and
directing the sale and disposal of the Vessel, and Mortgagee may become the
purchaser at such sale and shall have the right to credit against the purchase
price any and all sums of money due hereunder, and (iii) to have full rights and
remedies at law and in equity including, without limitation, specific
performance of the covenants hereof including, without limitation, the following
paragraph of this Section 3.3(c).

         Mortgagor further covenants and agrees that if (i) an Indenture Event
of Default under Section 6.1(a), (d), (e), (f), (j), (l) or (m) has occurred and
is continuing or (ii) any other Indenture

                                      -13-
 

<PAGE>   15



Event of Default has occurred and is continuing which has resulted in
acceleration of the maturity of the Obligations, then Mortgagor shall, upon the
request of Mortgagee and at the direction of Majority Holders, immediately move
the Vessel to such United States port or other location within the territorial
waters of the United States subject to the in rem admiralty jurisdiction of the
United States federal courts as Mortgagee may designate in its sole and absolute
discretion.

                  (d) Notice to Mortgagor. Mortgagee shall notify Mortgagor
promptly after taking any action permitted by this Section 3.3.

         Section 3.4 Restoration of Position. In case Mortgagee shall have
proceeded to enforce any right, power or remedy under this Mortgage by
foreclosure, entry or otherwise, and such proceeding shall have been
discontinued or abandoned for any reason or shall have been determined adversely
to Mortgagee, then and in every such case Mortgagor and Mortgagee shall, subject
to any determination in such proceeding, be restored to their former positions
and rights hereunder with respect to the property subject or intended to be
subject to this Mortgage, and all rights, remedies and powers of Mortgagee
shall, subject to any determination in such proceeding, continue as if no such
proceedings had been taken.

         Section 3.5 Application of Proceeds. The proceeds of any sale and net
earnings derived from the operation, use, charter, or any other employment of
the Vessel by Mortgagee, as mortgage creditor, and within any of the powers and
authority above given, as well as the proceeds of any judgment which Mortgagee
may obtain by reason of the breach or failure to perform any of the terms of
this Mortgage, as well as the proceeds of any claim for damage received by
Mortgagee while exercising the powers and the authorities above given shall be
applied as follows:

                  (i) to the payment of all charges and expenses, including the
         costs of any public or private sale or sales, the cost of replevying or
         taking possession of the Vessel which may be incurred or paid out by
         Mortgagee, as mortgage creditor, and the expenses and reasonable
         administrator and external attorneys' fees incurred on foreclosure or
         in the protection of the rights and interests of Mortgagee founded upon
         this Mortgage;

                  (ii) to pay or to furnish indemnity in the proper amounts
         against any Liens which have or may (in the reasonable opinion of
         Mortgagee) have priority over the Lien of this Mortgage and which are
         not Liens permitted under this Mortgage; and

                  (iii) to deliver to the Mortgagee for application as provided
         in the Trust Indenture.

         Section 3.6 Waiver. (a) To the extent now or at any time hereafter
enforceable under applicable law, the Mortgagor covenants that it will not at
any time insist upon or plead, or in any manner whatsoever claim or take any
benefit or advantage of, any stay or extension law now or at any time hereafter
in force, nor claim, take nor insist upon any benefit or advantage of or from
any law now or hereafter in force providing for the valuation or appraisement of
the Vessel or any part thereof, prior to any sale or sales thereof to be made
pursuant to any provision herein contained, or to the decree, judgment or order
of any court of competent jurisdiction, nor, after such sale or sales, claim or
exercise any right under any statute now or hereafter made or enacted by any
state or

                                      -14-
 

<PAGE>   16



otherwise to redeem the property so sold or any part thereof, and hereby
expressly waives for itself and on behalf of each and every Person, all benefit
and advantage of any such law or laws, and covenants that it will not invoke or
utilize any such law or laws or otherwise hinder, delay or impede the execution
of any power herein granted and delegated to the Mortgagee, but will suffer and
permit the execution of every such power as though no such law or laws had been
made or enacted.

                  (b) The Mortgagor waives any right to require the Mortgagee or
the Lenders to proceed against any other Person, or to exhaust any other
Collateral or other security for the obligations secured hereby, or to have any
other Person joined with the Mortgagor in any suit arising out of the
Obligations or the other Credit Documents, or to pursue any other remedy in the
Mortgagee's or the Lenders' power. The Mortgagor further waives any and all
notice of acceptance of this Mortgage by any other Person directly or indirectly
liable for such obligations from time to time. The Mortgagor further waives any
defense arising by reason of any disability or other defense of any other Person
or by reason of the cessation from any cause whatsoever of the liability of any
other Person liable for the Obligations secured hereby. Until all of such
Obligations shall have been paid in full, the Mortgagor shall have no right to
subrogation and the Mortgagor waives the right to enforce any remedy which the
Mortgagee or the Lenders have or may hereafter have against any other Person
liable for such obligations, and the Mortgagor waives any benefit of any right
to participate in any security whatsoever now or hereafter held by the Mortgagee
or the Lenders. The Mortgagor authorizes the Mortgagee and the Lenders, without
notice or demand and without any reservation of rights against the Mortgagor and
without affecting the Mortgagor's liability hereunder or on the obligations
secured hereby, from time to time to (a) take or hold any Property other than
the Collateral from any other Person as security for such obligations, and
exchange, enforce, waive and release any or all of such Property, (b) apply such
Property and direct the order or manner of sale thereof as the Mortgagee and the
Lenders may in their discretion determine, and (c) renew, extend for any period,
accelerate, modify, compromise, settle or release any of the obligations of any
other Person in respect of the obligations secured hereby or other security for
such obligations.


                                   ARTICLE IV

                           GENERAL POWERS OF MORTGAGEE

         Section 4.1  General Powers of Mortgagee.

                  (a) Arrest or Detention of Vessel. In the event that the
Vessel shall be arrested or detained by a marshal or other officer of any court
of law, equity or admiralty jurisdiction in any country or nation of the world
or by any government or other entity and shall not be released from arrest or
detention within fifteen (15) days from the date of arrest or detention or upon
Mortgagee's receipt of a Notice of Entitlement to Terminate as a result of such
detention or arrest, Mortgagor does hereby authorize and empower Mortgagee, in
the name of Mortgagor, or its successors or assigns, to apply for and receive
possession of and to take possession of the Vessel with all the rights and
powers that Mortgagor, or its successors or assigns, might have, possess or
exercise in any such event; and this power of attorney shall be irrevocable and
may be exercised not only by Mortgagee

                                      -15-

 

<PAGE>   17



but also by its appointee or appointees, with full power of substitution, to the
same extent as if the said appointee or appointees had been named as the
attorney above named by express designation.

                  (b) Suits. Mortgagor also authorizes and empowers Mortgagee or
its appointees or any of them to appear in the name of Mortgagor, its successors
or assigns, in any court of any country or nation of the world where a suit is
pending against the Vessel because of or on account of any alleged Lien against
the Vessel from which the Vessel has not been released in accordance with the
terms of this Mortgage and to take such proceedings as to it may seem proper
towards the defense of such suit and the discharge of such Lien.

                  (c) Reimbursement of Expenses. If Mortgagor fails to perform
any obligation or covenant under this Mortgage, Mortgagee shall have the right,
but not the obligation, to perform or take such actions to comply with the terms
of this Mortgage, and all amounts reasonably expended in connection with such
conduct shall be a demand obligation of Mortgagor owing to Mortgagee at the
Default Rate specified in the Trust Indenture and shall be secured by the Lien
of this Mortgage.

                                    ARTICLE V

                                SUNDRY PROVISIONS

         Section 5.1 Release. If the Obligations shall have been fully satisfied
and discharged to the satisfaction of the Trustee then this Mortgage and the
estate and rights hereunder shall cease, determine, and become null and void;
and Mortgagee, on the request of Mortgagor and at Mortgagor's cost and expense,
shall forthwith cause satisfaction and discharge of this Mortgage to be entered
upon its and other appropriate records and shall execute and deliver to
Mortgagor such instruments as may be necessary in Mortgagor's reasonable opinion
to duly acknowledge the satisfaction and discharge of this Mortgage. Upon any
termination of this Mortgage or release of the Vessel as permitted by the Trust
Indenture, Mortgagee will, at the expense of Mortgagor, execute and deliver to
Mortgagor such documents and take such other actions as Mortgagor shall
reasonably request to evidence the termination of this Mortgage or the release
of the Vessel, as the case may be.

         Section 5.2 Right of Peaceful Enjoyment. During the term of this
Mortgage and so long as no Event of Default shall have occurred and be
continuing, Mortgagor shall have full and peaceful enjoyment, use, right to
possession and control of the Vessel subject to the terms of the Credit
Documents.

         Section 5.3 Cumulative Remedies; No Waiver. Each and every power and
remedy herein given to Mortgagee shall be cumulative and shall be in addition to
every other power and remedy herein or in any other Credit Document or now or
hereafter existing at law, in equity, in admiralty, or by statute, and each and
every power and remedy whether herein given or given in any other Credit
Document or otherwise existing may be exercised from time to time and as often
and in such order, or in the alternative as may be deemed expedient by
Mortgagee, and the exercise or the beginning of the exercise of any power or
remedy shall not be construed to be a waiver of the right to exercise at the
same time or thereafter any other power or remedy. No course of dealing on the

                                      -16-
 

<PAGE>   18



part of Mortgagee, its officers, employees, consultants or agents, nor any delay
or omission by Mortgagee in the exercise of any right or power or in the
pursuance of any remedy shall operate as a waiver of any such right, power or
remedy.

         Section 5.4 Further Assurances. In the event that this Mortgage, or any
provisions hereof, shall be deemed invalid in whole or in part by reason of any
present or future law or any decision of any court having jurisdiction, or if
the documents at any time held by Mortgagee shall be deemed by Mortgagee for any
reason insufficient to carry out the rights and powers granted to Mortgagee
herein, then, from time to time, Mortgagor will do, execute, acknowledge and
deliver, or cause to be done, executed, acknowledged and delivered, such other
and further assurances and documents as in the opinion of Mortgagee may
reasonably be required in order to more effectively subject the Vessel to the
Lien of this Mortgage or more effectively subject the Vessel to the performance
of the terms and provisions of this Mortgage, or to enable this Mortgage to
continuously enjoy the status of a first preferred ship mortgage.

         Section 5.5 Survival of Agreements. All representations, warranties,
covenants and agreements herein contained or made in writing in connection with
this Mortgage shall survive the execution of this Mortgage and shall continue in
full force and effect until all sums secured hereby shall have been paid in
full, and the same shall bind and inure to the benefit of the respective
successors and assigns of Mortgagor and Mortgagee.

         Section 5.6 Notices. All notices, requests and demands to or upon the
respective parties hereto to be effective shall be in writing (including by
facsimile transmission), and, unless otherwise expressly provided herein, shall
be deemed to have been duly given or made when actually delivered or in the case
of facsimile transmission, when received and telephonically confirmed, addressed
as follows or to such other address as may be hereafter notified by the
respective parties hereto or any assignee thereof or successor thereto:

         Mortgagor:        Noble Drilling (Paul Romano) Inc.
                           10370 Richmond Avenue
                           Suite 581
                           Houston, Texas  77042
                           Facsimile No. 713-974-3181
                           Attention:  President

         Mortgagee:        Chase Bank of Texas, National Association
                           600 Travis Street, Suite 1150
                           11th Floor
                           Houston, Texas 77002
                           Attention:  Mauri Cowen
                                       Corporate Trust Department

         Section 5.7 Counterparts. This instrument may be executed in any number
of counterparts, and each of such counterparts shall for all purposes be deemed
to be an original.


                                      -17-
 

<PAGE>   19



         Section 5.8 Section Headings. The section headings used in this
Mortgage are for convenience of reference only and are not to affect the
construction of or be taken into consideration in interpreting this Mortgage.

         SECTION 5.9 GOVERNING LAW. THIS MORTGAGE, AND ALL OF THE RIGHTS AND
OBLIGATIONS OF THE PARTIES HEREUNDER, AND THEIR RESPECTIVE SUCCESSORS AND
ASSIGNS, SHALL BE GOVERNED BY THE LAWS OF THE REPUBLIC OF PANAMA AND, BY THE
MARITIME LAWS OF THE UNITED STATES OF AMERICA OR THE STATE OF NEW YORK AS MAY BE
APPLICABLE.

         Section 5.10 Jurisdiction.

         (a) Any legal action or proceeding with respect to this Mortgage may be
brought in the courts of the United States for the Southern District of New York
and the Mortgagor hereby accepts for itself and its property, generally and
unconditionally, the non-exclusive jurisdiction of such court. The Mortgagor
further irrevocably consents to the service of process out of such court in any
such action or proceeding in the manner provided for in the Trust Indenture.
Nothing herein shall affect the right of the Mortgagee to serve process in any
other manner permitted by law or to commence legal proceedings or otherwise
proceed against the Mortgagor in any other jurisdiction.

         (b) Without prejudice to the generality of Clause 5.10(a), the
Mortgagee shall have the right to arrest and take action against the Vessel at
whatever place such Vessel shall be found lying and for the purpose of any
action which the Mortgagee may bring before the courts of such jurisdiction or
other judicial authority and for the purpose of any action which the Mortgagee
may bring against such Vessel, any writ, notice, judgment or other legal process
or documents may (without prejudice to any other method of service under
applicable law) be served upon the master of such Vessel (or upon anyone acting
as the master) and such service shall be deemed good service on the Mortgagor
for all purposes.

         (c) Each of the parties hereto stipulates that, when the Vessel is
located on the Outer Continental Shelf within the jurisdiction of the United
States Federal District Courts under 43 U.S.C. ss.ss.1331(1) and 1349(b)(1), (i)
that the United States Federal District Courts shall have "in rem" admiralty
jurisdiction over the Vessel and (ii) that the Vessel is present within the
territorial jurisdiction of said courts for all purposes, including the
enforcement of any maritime liens or other remedies hereunder.

         Section 5.11 Amendments and Waivers. None of the terms or provisions of
this Mortgage may be waived, amended, supplemented or otherwise modified except
if made in compliance with the terms and provisions of the Trust Indenture.

         Section 5.12 Termination. The grant of the Liens hereunder and all of
Mortgagee's rights, powers and remedies in connection therewith, shall unless
otherwise provided in the Trust Indenture or this Mortgage, remain in full force
and effect until payment in full of (A) the Notes under the terms thereof or of
the Trust Indenture, and (B) all Obligations then due and owing under the Trust
Indenture, the Notes and the other Credit Documents. Upon the payment in full of
(A) the Notes

                                      -18-
 

<PAGE>   20



under the terms thereof or of the Trust Indenture, and (B) all Obligations then
due and owing under the Trust Indenture, the Notes and the other Credit
Documents, Mortgagor shall be entitled to the return, upon its request and at
its expense, of the Vessel free and clear of all liens created by this Mortgage.

         Section 5.13 Trust Indenture. This Mortgage is issued pursuant to the
terms, conditions and provisions of the Trust Indenture.

         Section 5.14 Severability. In the event that any provision of this
Mortgage or the Trust Indenture or the Notes shall be deemed invalid or
unenforceable by reason of any present or future law or any decision of any
authoritative court, the validity and enforceability of the other provisions
hereof or thereof shall not be affected thereby.

         Section 5.15 Power to Record. Mortgagee and Mortgagor declare that they
hereby confer a special Power of Attorney on Roy Phillipps P., a lawyer of
Panama, Republic of Panama, empowering him to take all necessary steps to file
and register this First Naval Mortgage in the appropriate registries of the
Republic of Panama.


                        [Signature Pages Begin Next Page]




                                      -19-
 

<PAGE>   21



         IN WITNESS WHEREOF, Mortgagor has caused this Mortgage to be duly
executed as of the day and year first above written.


MORTGAGOR:                                     NOBLE DRILLING (PAUL ROMANO) INC.


                                               By:
                                                  -----------------------------
                                                  Name:
                                                  Title:


THE STATE OF TEXAS     )
                       )
COUNTY  OF  HARRIS     )


         THIS INSTRUMENT was acknowledged before me on __________, 1998, by
_____________________________, ___________________________________ of Noble
Drilling (Paul Romano) Inc., a Delaware corporation on behalf of such
corporation, and after having first been duly authorized by said corporation to
do so.

         AND THE said ___________ did further produce to me sufficient proof
that he is the duly elected ___________ of said corporation and that he was duly
authorized by said corporation to execute the foregoing Mortgage, and I the
notary hereby certify that the signature of the said ______________ on the
foregoing Mortgage was placed thereon in my presence and is therefore authentic.


                                               ------------------------------
                                               Notary Public in and for
                                               the State of Texas

                                               Printed Name of Notary:

                                               ------------------------------


                                               My Commission Expires:

                                               ------------------------------




                               Signature Page - 1
 

<PAGE>   22


MORTGAGEE:                                    CHASE BANK OF TEXAS, National
                                              Association, as Indenture Trustee,


                                              By:
                                                 ---------------------------
                                                 Name:
                                                 Title:


THE STATE OF TEXAS              )
                                )
COUNTY  OF  HARRIS              )

         THIS INSTRUMENT was acknowledged before me on __________, 1998, by
_____________________________, __________________ of Chase Bank of Texas,
National Association, a national banking association, on behalf of such
association, and after having first been duly authorized by said association to 
do so.

         AND THE said ___________ did further produce to me sufficient proof
that he is the duly elected ___________ of said association and that he was duly
authorized by said association to execute the foregoing Mortgage, and I the
notary hereby certify that the signature of the said ______________ on the
foregoing Mortgage was placed thereon in my presence and is therefore authentic.


                                               ------------------------------
                                               Notary Public in and for
                                               the State of Texas

                                               Printed Name of Notary:

                                               ------------------------------


                                               My Commission Expires:

                                               ------------------------------






                               Signature Page - 2



<PAGE>   1
                                                                     EXHIBIT 4.4







================================================================================




                        NOBLE DRILLING (PAUL WOLFF) LTD.,


                                  $145,000,000


                         Fixed Rate Senior Secured Notes




                                 --------------

                             NOTE PURCHASE AGREEMENT
                                 --------------





                            Dated as of July 1, 1998







================================================================================







<PAGE>   2




                                TABLE OF CONTENTS



<TABLE>
<CAPTION>

<S>                                                                                                              <C>
SECTION 1. AUTHORIZATION, PURCHASE AND SALE OF NOTES...............................................................1
   1.01 Authorization and Commitment to Purchase...................................................................1
   1.02 Disbursement of Funds......................................................................................2
   1.03 Interest...................................................................................................2
SECTION 2. FEES; COMMITMENTS.......................................................................................3
   2.01 Fees.......................................................................................................3
   2.02 Termination of Commitments.................................................................................3
SECTION 3. PAYMENTS................................................................................................3
   3.01 Voluntary Prepayments......................................................................................3
   3.02 Mandatory Repayments.......................................................................................5
   3.03 Method and Place of Payment................................................................................7
   3.04 Net Payments...............................................................................................7
   3.05 Purchase of Notes..........................................................................................8
SECTION 4. CONDITIONS PRECEDENT....................................................................................8
   4.01 Execution of Agreement.....................................................................................8
   4.02 No Default; Representations and Warranties.................................................................8
   4.03 Officers Certificate.......................................................................................8
   4.04 Opinions of Counsel........................................................................................8
   4.05 Corporate Proceedings......................................................................................9
   4.06 Construction Contract......................................................................................9
   4.07 Adverse Change, etc........................................................................................9
   4.08 Litigation.................................................................................................9
   4.09 Approvals.................................................................................................10
   4.10 Fees......................................................................................................10
   4.11 Guaranties................................................................................................10
   4.12 Insurance Report..........................................................................................10
   4.13 Assignment of Insurances..................................................................................10
   4.14 Mortgages.................................................................................................10
   4.15 Purchase Permitted By Applicable Law, etc.................................................................10
   4.16 Sale of Other Notes.......................................................................................11
   4.17 Private Placement Number..................................................................................11
SECTION 5. REPRESENTATIONS, WARRANTIES AND AGREEMENTS.............................................................11
   5.01 Corporate Status..........................................................................................11
   5.02 Corporate Power and Authority.............................................................................11
   5.03 No Violation..............................................................................................12
   5.04 Litigation................................................................................................12
   5.05 Use of Proceeds; Margin Regulations.......................................................................12
   5.06 Governmental Approvals....................................................................................12
   5.07 Investment Company Act....................................................................................13
   5.08 Public Utility Holding Company Act........................................................................13
   5.09 True and Complete Disclosure..............................................................................13
   5.10 Financial Condition.......................................................................................13
   5.11 Tax Returns and Payments..................................................................................13
   5.12 Employee Benefit Plans....................................................................................13
   5.13 Subsidiaries..............................................................................................14
</TABLE>


                                      (i)
<PAGE>   3

<TABLE>
<CAPTION>

<S>                                                                                                               <C>
   5.14 Patents, etc..............................................................................................14
   5.15 Pollution and Other Regulations...........................................................................14
   5.16 Properties................................................................................................15
   5.17 Labor Relations...........................................................................................15
   5.18 Existing Indebtedness.....................................................................................15
   5.19 Rig Classification........................................................................................15
   5.20 Security Interests........................................................................................15
   5.21 Foreign Assets Control Regulations, etc...................................................................16
   5.22 Compliance with Laws, etc.................................................................................16
   5.23 Offering of the Notes.....................................................................................16
SECTION 6. AFFIRMATIVE COVENANTS..................................................................................16
   6.01 Information Covenants.....................................................................................16
   6.02 Books, Records and Inspections............................................................................17
   6.03 Maintenance of Property; Insurance........................................................................17
   6.04 Payment of Taxes..........................................................................................17
   6.05 Consolidated Corporate Franchises.........................................................................17
   6.07 Good Repair...............................................................................................18
   6.08 End of Fiscal Years; Fiscal Quarters......................................................................18
   6.09 Use of Proceeds...........................................................................................18
   6.10 ERISA.....................................................................................................18
   6.11 Earnings Concentration Account............................................................................18
   6.12 Further Assurances........................................................................................19
   6.13 Nature of Business........................................................................................19
SECTION 7. NEGATIVE COVENANTS.....................................................................................20
   7.01 Changes in Business.......................................................................................20
   7.02 Consolidation, Merger, Sale of Assets, etc................................................................20
   7.03 Indebtedness..............................................................................................20
   7.04 Liens.....................................................................................................21
   7.05 Restricted Payments.......................................................................................22
   7.06 Restrictions on Subsidiaries..............................................................................22
   7.07 Transactions with Affiliates..............................................................................22
   7.08 Vessel Management.........................................................................................22
SECTION 8. EVENTS OF DEFAULT......................................................................................23
   8.01 Payments..................................................................................................23
   8.02 Representations, etc......................................................................................23
   8.03 Covenants.................................................................................................23
   8.04 Default Under Other Agreements............................................................................23
   8.05 Bankruptcy, etc...........................................................................................23
   8.06 Parent Guaranty...........................................................................................24
   8.07 Judgments.................................................................................................24
   8.08 Employee Benefit Plans....................................................................................24
   8.09 Change of Control.........................................................................................25
   8.10 Vessel in Class...........................................................................................25
SECTION 9. DEFINITIONS............................................................................................25
SECTION 10. THE TRUSTEE...........................................................................................35
   10.01 Appointment..............................................................................................35
   10.02 Nature of Duties.........................................................................................36
   10.03 Lack of Reliance on the Trustee..........................................................................36
   10.04 Certain Rights of the Trustee............................................................................37
</TABLE>


                                      (ii)
<PAGE>   4


<TABLE>
<CAPTION>

<S>                                                                                                              <C>
   10.05 Reliance.................................................................................................37
   10.06 Indemnification..........................................................................................37
   10.07 The Trustee in Its Individual Capacity...................................................................38
   10.08 Holders..................................................................................................38
   10.09 Resignation by the Trustee...............................................................................38
   10.10 Concentration Account....................................................................................39
   10.11 Insurance................................................................................................39
   10.12 Knowledge of Defaults....................................................................................39
SECTION 11. MISCELLANEOUS.........................................................................................39
   11.01 Payment of Expenses, etc.................................................................................40
   11.02 Right of Setoff..........................................................................................41
   11.03 Notices..................................................................................................41
   11.04 Successors and Assigns - Representations of the Purchasers...............................................41
   11.05 No Waiver; Remedies Cumulative...........................................................................43
   11.06 Payments Pro Rata........................................................................................43
   11.07 Computations.............................................................................................44
   11.08 Governing Law; Submission to Jurisdiction; Venue; Waiver of Jury Trial...................................44
   11.09 Counterparts.............................................................................................45
   11.10 Effectiveness............................................................................................45
   11.11 Headings Descriptive.....................................................................................45
   11.12 Amendment or Waiver......................................................................................46
   11.13 Survival.................................................................................................46
   11.14 Domicile of Notes........................................................................................46
   11.15 Confidentiality..........................................................................................46
   11.16(a) Registration of Notes, etc............................................................................47
</TABLE>


ANNEX I  --     Commitments
ANNEX II*--     Purchaser Addresses

EXHIBIT A-1* --  Form of Series A Note 
EXHIBIT A-2* --  Form of Series B Note 
EXHIBIT A-3* --  Form of Series C Note
EXHIBIT B-1* --  Form of Opinion of Maples and Calder 
EXHIBIT B-2* --  Form of Opinion of Thompson & Knight, P.C.
EXHIBIT B-3* --  Form of Opinion of Watson, Farley & Williams 
EXHIBIT B-4* --  Form of Opinion of Roy Phillips P. 
EXHIBIT B-5* --  Form of Opinion of White & Case
EXHIBIT C*   --  Form of Officers' Certificate 
EXHIBIT D-1* --  Form of Parent Guaranty 
EXHIBIT D-2* --  Form of Subsidiary Guaranty 
EXHIBIT E*   --  Form of Mortgage 
EXHIBIT F*   --  Assignments of Insurances

- - ------------
* Not filed as part of this Exhibit 4.4 or as a separate exhibit to this 
  Quarterly Report on Form 10-Q.  The Company undertakes to furnish 
  supplementally a copy of any omitted material to the Commission upon 
  request.

                                     (iii)

<PAGE>   5




                         FIXED RATE SENIOR SECURED NOTES


                                                                    July 1, 1998


To Each of the Purchasers Named
in Annex I Attached Hereto:


Ladies and Gentlemen:


         The undersigned, Noble Drilling (Paul Wolff) Ltd., a company organized
and existing under the laws of the Cayman Islands (the "Company") agrees with
the purchasers named in annex I attached hereto and any successors and assigns
thereof as holders of the Notes (each a "Purchaser" and, collectively, the
"Purchasers") and the Company and the Purchasers agree with Chase Bank of Texas,
National Association, as Trustee as follows:

SECTION 1.   AUTHORIZATION, PURCHASE AND SALE OF NOTES.

         1.01 Authorization and Commitment to Purchase. (a) The Company will
authorize the issue and sale of $145,000,000 aggregate principal amount of its
Fixed Rate Senior Secured Notes due December 1, 2001, December 1, 2004 and
December 1, 2004, respectively, which Notes shall be divided among Series A
Notes, Series B Notes and Series C Notes according to the Commitments of the
Purchasers set forth on Annex I hereto. The Notes shall be substantially in the
form of (i) Exhibit A-1, if issued pursuant to the Series A Commitment (each a
"Series A Note" and, collectively, the "Series A Notes"), (ii) Exhibit A-2, if
issued pursuant to the Series B Commitment (each a "Series B Note" and,
collectively, the "Series B Notes") and (iii) Exhibit A-3, if issued pursuant to
the Series C Commitment (each a "Series C Note" and, collectively, the "Series C
Notes" and, together with the Series A Notes and the Series B Notes, each a
"Note" and, collectively, the "Notes"), in each case with blanks appropriately
completed in conformity therewith.

         (b) The Company agrees to sell and, subject to and upon the terms and
conditions herein set forth, each Purchaser severally but not jointly agrees to
purchase, on the Drawdown Date, for a purchase price equal to 100% of the
principal amount thereof, Series A Notes in a principal amount equal to each
such Purchaser's Series A Commitment, which Series A Notes (i) shall, in the
aggregate for all Purchasers, be equal to the Total Series A Commitment (unless
terminated prior to the Drawdown Date pursuant to Section 2.02) and (ii) shall
not exceed for any Purchaser the Series A Commitment of such Purchaser on the
Drawdown Date (unless terminated prior to the Drawdown Date pursuant to Section
2.02). Once repaid, the Series A Notes issued hereunder may not be reissued.

         (c) The Company agrees to sell and, subject to and upon the terms and
conditions herein set forth, each Purchaser severally but not jointly agrees to
purchase, on the Drawdown Date, for a purchase price equal to 100% of the
principal amount thereof, Series B Notes in a principal amount equal to each
such Purchaser's Series B 




<PAGE>   6

Commitment, which Series B Notes (i) shall, in the aggregate for all Purchasers,
be equal to the Total Series B Commitment (unless terminated prior to the
Drawdown Date pursuant to Section 2.02) and (ii) shall not exceed for any
Purchaser the Series B Commitment of such Purchaser on the Drawdown Date (unless
terminated prior to the Drawdown Date pursuant to Section 2.02). Once repaid,
the principal of Series B Notes issued hereunder may not be reissued.

         (d) The Company agrees to sell and, subject to and upon the terms and
conditions herein set forth, each Purchaser severally but not jointly agrees to
purchase, on the Drawdown Date, for a purchase price equal to 100% of the
principal amount thereof, Series C Notes in a principal amount equal to each
such Purchaser's Series C Commitment, which Series C Notes (i) shall, in the
aggregate for all Purchasers, be equal to the Total Series C Commitment (unless
terminated prior to the Drawdown Date pursuant to Section 2.02) and (ii) shall
not exceed for any Purchaser the Series C Commitment of such Purchaser on the
Drawdown Date (unless terminated prior to the Drawdown Date pursuant to Section
2.02). Once repaid, the Series C Notes issued hereunder may not be reissued.

         1.02 Disbursement of Funds. The sale and purchase of the Notes to be
purchased by you and the other Purchasers shall occur at the offices of White &
Case LLP, 1155 Avenue of the Americas, New York, New York 10036, at 10:00 a.m.,
New York City time, at a closing (the "CLOSING") on July 1, 1998 or on such
other Business Day thereafter on or prior to July 15, 1998 as may be agreed upon
by the Company and you and the other Purchasers. At the Closing the Company will
deliver to each Purchaser the Notes to be purchased by such Purchaser in the
form of a single Note (or such greater number of Notes in denominations of at
least $100,000 as you may request) dated the date of the Closing and registered
in your name (or in the name of your nominee). If at the Closing the Company
shall fail to tender such Notes to you as provided above in this Section 1.02,
or any of the conditions specified in Section 4 shall not have been fulfilled to
your satisfaction, you shall, at your election, be relieved of all further
obligations under this Agreement, without thereby waiving any rights you may
have by reason of such failure or such nonfulfillment. On the closing date, each
Purchaser will make available to the Company, in Dollars and immediately
available funds to the account of the Company specified to the Purchasers in
writing, its pro rata share of the Total Commitment on such date.

         1.03 Interest. (a) The unpaid principal amount of each Note shall bear
interest from the Drawdown Date until maturity (whether by acceleration or
otherwise) at a rate per annum which shall at all times be (i) in the case of
Series A Notes, the Series A Rate, (ii) in the case of Series B Notes, the
Series B Rate and (iii) in the case of Series C Notes, the Series C Rate.

         (b) All overdue principal and, to the extent permitted by law, overdue
interest in respect of each Note and any other overdue amount payable hereunder
shall bear interest at a rate per annum equal to 2% per annum in excess of the
interest rate applicable to such Notes at maturity, with such interest payable
on demand.

         (c) Interest shall accrue from and including the Drawdown Date to but
excluding the date of repayment of the Notes and shall be payable quarterly in
arrears on each



                                      -2-
<PAGE>   7

Scheduled Repayment Date, upon prepayment (on the amount prepaid) and at
maturity (whether by acceleration or otherwise) and, after such maturity, on
demand.

         (d) All computations of interest hereunder shall be made in accordance
with Section 11.07.

SECTION 2.  FEES; COMMITMENTS.

         2.01 Fees. (a) The Company shall pay to the Trustee (x) on the
Effective Date, for its own account and/or for distribution to the Arrangers,
such Fees as heretofore agreed in writing by the Company and the Arrangers and
(y) for its own account such other fees as agreed to in writing between the
Company and the Trustee, when and as due.

         (b) All computations of Fees shall be made in accordance with Section
11.07.

         2.02 Termination of Commitments. The Total Commitment (and the
Commitments of each Purchaser) shall terminate in its entirety on the earlier of
(i) July 15, 1998 and (ii) the Drawdown Date (immediately after giving effect to
the purchase of the Notes on such date).

SECTION 3.  PAYMENTS.

         3.01 Voluntary Prepayments. (a) The Company shall have the right to
prepay the Notes pro rata among each Series of Notes, in whole or in part, from
time to time after June 1, 2001 at 100% of the outstanding principal balance of
such Series of Notes (or portion thereof) plus accrued interest and the
Make-Whole Amount. The Company shall give the Purchasers written notice (or
telephonic notice promptly confirmed in writing) of its intent to prepay the
Notes and the amount of such prepayment, which notice shall be given by the
Company not less than 30 nor more than 60 days prior to the date of such
prepayment; (x) each partial prepayment of Notes shall be in an aggregate
principal amount of at least $10,000,000 and, if greater, in an integral
multiple of $100,000, provided that no partial prepayment of Notes shall reduce
the aggregate principal amount of the Notes outstanding to an amount less than
$10,000,000; (y) each prepayment of Notes in a Series shall be applied pro rata
among the Purchasers which have Notes of such Series outstanding; and (z) each
voluntary prepayment of any Series of Notes pursuant to this Section 3.01 shall
be applied to reduce the then remaining Scheduled Repayments of such Series pro
rata based on the then remaining amount of each Scheduled Repayment after giving
effect to all prior reductions thereto.

                  (b) The term "MAKE-WHOLE AMOUNT" means, with respect to any
Note, an amount equal to the excess, if any, of the Discounted Value of the
Remaining Scheduled Payments with respect to the Called Principal of such Note
over the amount of such Called Principal, provided that the Make-Whole Amount
may in no event be less than zero. For the purposes of determining the
Make-Whole Amount, the following terms have the following meanings:



                                      -3-
<PAGE>   8


                  "CALLED PRINCIPAL" means, with respect to any Note, the
         principal of such Note that is to be prepaid pursuant to Section 3.01
         or has become or is declared to be immediately due and payable pursuant
         to Section 8, as the context requires.

                  "DISCOUNTED VALUE" means, with respect to the Called Principal
         of any Note, the amount obtained by discounting all Remaining Scheduled
         Payments with respect to such Called Principal from their respective
         scheduled due dates to the Settlement Date with respect to such Called
         Principal, in accordance with accepted financial practice and at a
         discount factor (applied on the same periodic basis as that on which
         interest on the Notes is payable) equal to the Reinvestment Yield with
         respect to such Called Principal.

                  "REINVESTMENT YIELD" means, with respect to the Called
         Principal of any Note, 0.50% over the yield to maturity implied by (i)
         the yields reported, as of 10:00 A.M. (New York City time) on the
         second Business Day preceding the Settlement Date with respect to such
         Called Principal, on the display designated as "Page 500" on the
         Telerate Access Service (or such other display as may replace Page 500
         on Telerate Access Service) for actively traded U.S. Treasury
         securities having a maturity equal to the Remaining Average Life of
         such Called Principal as of such Settlement Date, or (ii) if such
         yields are not reported as of such time or the yields reported as of
         such time are not ascertainable, the Treasury Constant Maturity Series
         Yields reported, for the latest day for which such yields have been so
         reported as of the second Business Day preceding the Settlement Date
         with respect to such Called Principal, in Federal Reserve Statistical
         Release H.15 (519) (or any comparable successor publication) for
         actively traded U.S. Treasury securities having a constant maturity
         equal to the Remaining Average Life of such Called Principal as of such
         Settlement Date. Such implied yield will be determined, (A) if
         necessary, by (x) converting U.S. Treasury bill quotations to
         bond-equivalent yields in accordance with accepted financial practice
         and (y) interpolating linearly between (1) the actively traded U.S.
         Treasury security with the duration closest to and greater than the
         Remaining Average Life and (2) the actively traded U.S. Treasury
         security with the duration closest to and less than the Remaining
         Average Life and (B) by converting all such implied yields to a
         quarterly payment basis in accordance with accepted financial practice.

                  "REMAINING AVERAGE LIFE" means, with respect to any Called
         Principal, the number of years (calculated to the nearest one-twelfth
         year) obtained by dividing (i) such Called Principal into (ii) the sum
         of the products obtained by multiplying (a) the principal component of
         each Remaining Scheduled Payment with respect to such Called Principal
         by (b) the number of years (calculated to the nearest one-twelfth year)
         that will elapse between the Settlement Date with respect to such
         Called Principal and the scheduled due date of such Remaining Scheduled
         Payment.

                  "REMAINING SCHEDULED PAYMENTS" means, with respect to the
         Called Principal of any Note, all payments of such Called Principal and
         interest thereon that would be due after the Settlement Date with
         respect to such Called Principal if no payment of such Called Principal
         were made prior to its scheduled due date,




                                      -4-
<PAGE>   9

         provided that if such Settlement Date is not a date on which interest
         payments are due to be made under the terms of the Notes, then the
         amount of the next succeeding scheduled interest payment will be
         reduced by the amount of interest accrued to such Settlement Date and
         required to be paid on such Settlement Date pursuant to Section 3.01 or
         Section 8.

                  "SETTLEMENT DATE" means, with respect to the Called Principal
         of any Note, the date on which such Called Principal is to be prepaid
         pursuant to Section 3.01 or has become or is declared to be immediately
         due and payable pursuant to Section 8, as the context requires.

         3.02 Mandatory Repayments. (a) In addition to any other mandatory
repayments pursuant to this Section 3.02, on each date set forth below, the
Company shall repay interest on and principal of the Series A Notes, to the
extent then outstanding, in the amount set forth opposite such date (each such
repayment, as the same may be reduced from time to time pursuant to Section
3.01, a "Series A Scheduled Repayment" and each such date a "Series A Scheduled
Repayment Date"):

<TABLE>
<CAPTION>

- - ------------------------------------------------------------------------------------------------------------

Series A Scheduled Repayment Date        Interest Payment        Principal Payment      Total Payment
- - ------------------------------------------------------------------------------------------------------------
<S>                                      <C>                     <C>                    <C>        
September 1, 1998                        $428,666.67             $        0.00          $  428,666.67
December 1, 1998                         $643,000.00             $        0.00          $  643,000.00
March 1, 1999                            $643,000.00             $3,185,737.54          $3,828,737.54
June 1, 1999                             $591,789.27             $3,236,948.27          $3,828,737.54
September 1, 1999                        $539,755.33             $3,288,982.21          $3,828,737.54
December 1, 1999                         $486,884.94             $3,341,852.60          $3,828,737.54
March 1, 2000                            $433,164.66             $3,395,572.88          $3,828,737.54
June 1, 2000                             $378,580.82             $3,450,156.72          $3,828,737.54
September 1, 2000                        $323,119.55             $3,505,617.99          $3,828,737.54
December 1, 2000                         $266,766.74             $3,561,970.80          $3,828,737.54
March 1, 2001                            $209,508.06             $3,619,229.48          $3,828,737.54
June 1, 2001                             $151,328.95             $3,677,408.59          $3,828,737.54
September 1, 2001                        $ 92,214.61             $3,736,522.93          $3,828,737.54
December 1, 2001                         $ 32,150.00             $1,999,999.98          $2,032,149.98
- - ------------------------------------------------------------------------------------------------------------
</TABLE>


         (b) In addition to any other mandatory repayments pursuant to this
Section 3.02, on each date set forth below, the Company shall repay interest on
and principal of the Series B Notes, to the extent then outstanding, in the
amount set forth opposite such date (each such repayment, as the same may be
reduced from time to time pursuant to Section 3.01, a "Series B Scheduled
Repayment" and each such date a "Series B Scheduled Repayment Date"):

<TABLE>
<CAPTION>

- - -----------------------------------------------------------------------------------------------------

Series B Scheduled Repayment Date        Interest Payment     Principal Payment     Total Payment
- - -----------------------------------------------------------------------------------------------------
<S>                                      <C>                  <C>                   <C>        
September 1, 1998                        $650,000.00          $        0.00         $  650,000.00
December 1, 1998                         $975,000.00          $        0.00         $  975,000.00
March 1, 1999                            $975,000.00          $1,806,029.75         $2,781,029.75
June 1, 1999                             $945,652.02          $1,835,377.73         $2,781,029.75
September 1, 1999                        $915,827.13          $1,865,202.62         $2,781,029.75
December 1, 1999                         $885,517.59          $1,895,512.16         $2,781,029.75
</TABLE>


                                      -5-
<PAGE>   10

================================================================================


<TABLE>
<CAPTION>

<S>                                      <C>                  <C>                   <C>          
March 1, 2000                            $854,715.51          $1,926,314.24         $2,781,029.75
June 1, 2000                             $823,412.91          $1,957,616.84         $2,781,029.75
September 1, 2000                        $791,601.63          $1,989,428.12         $2,781,029.75
December 1, 2000                         $759,273.43          $2,021,756.32         $2,781,029.75
March 1, 2001                            $726,419.89          $2,054,609.86         $2,781,029.75
June 1, 2001                             $693,032.48          $2,087,997.27         $2,781,029.75
September 1, 2001                        $659,102.52          $2,121,927.23         $2,781,029.75
December 1, 2001                         $624,621.20          $2,679,335.08         $3,303,956.28
March 1, 2002                            $581,082.01          $2,722,874.27         $3,303,956.28
June 1, 2002                             $536,835.30          $2,767,120.98         $3,303,956.28
September 1, 2002                        $491,869.58          $2,812,086.70         $3,303,956.28
December 1, 2002                         $446,173,18          $2,857,783.10         $3,303,956.28
March 1, 2003                            $399,734.20          $2,904,222.08         $3,303,956.28
June 1, 2003                             $352,540.59          $2,951,415.69         $3,303,956.28
September 1, 2003                        $304,580.09          $2,999,376.19         $3,303,956.28
December 1, 2003                         $255,840.22          $3,048,116.06         $3,303,956.28
March 1, 2004                            $206,308.34          $3,097,647.94         $3,303,956.28
June 1, 2004                             $155,971.56          $3,147,984.72         $3,303,956.28
September 1, 2004                        $104,816.81          $3,199,139.47         $3,303,956.28
December 1, 2004                         $ 52,830.79          $3,251,125.55         $3,303,956.34
- - -----------------------------------------------------------------------------------------------------
</TABLE>

         (c) In addition to any other mandatory repayments pursuant to this
Section 3.02, on each date set forth below, the Company shall repay interest on
and principal of the Series C Notes, to the extent then outstanding, in the
amount set forth opposite such date (each such repayment, as the same may be
reduced from time to time pursuant to Section 3.01, a "Series C Scheduled
Repayment" and each such date a "Series C Scheduled Repayment Date"):

<TABLE>
<CAPTION>
- - -----------------------------------------------------------------------------------------------------

Series C Scheduled Repayment Date        Interest Payment    Principal Payment      Total Payment
- - -----------------------------------------------------------------------------------------------------
<S>                                      <C>                 <C>                    <C>        
September 1, 1998                        $491,250.00         $        0.00          $  491,250.00
December 1, 1998                         $736,875.00         $        0.00          $  736,875.00
March 1, 1999                            $736,875.00         $        0.00          $  736,875.00
June 1, 1999                             $736,875.00         $        0.00          $  736,875.00
September 1, 1999                        $736,875.00         $        0.00          $  736,875.00
December 1, 1999                         $736,875.00         $        0.00          $  736,875.00
March 1, 2000                            $736,875.00         $        0.00          $  736,875.00
June 1, 2000                             $736,875.00         $        0.00          $  736,875.00
September 1, 2000                        $736,875.00         $        0.00          $  736,875.00
December 1, 2000                         $736,875.00         $        0.00          $  736,875.00
March 1, 2001                            $736,875.00         $        0.00          $  736,875.00
June 1, 2001                             $736,875.00         $        0.00          $  736,875.00
September 1, 2001                        $736,875.00         $        0.00          $  736,875.00
December 1, 2001                         $736,875.00         $1,273,661.01          $2,010,536.01
March 1, 2002                            $716,018.80         $3,327,228.03          $4,043,246.83
June 1, 2002                             $661,535.44         $3,381,711.39          $4,043,246.83
September 1, 2002                        $606,159.92         $3,437,086.91          $4,043,246.83
December 1, 2002                         $549,877.62         $3,493,369.21          $4,043,246.83
March 1, 2003                            $492,673.70         $3,550.573.13          $4,043,246.83
June 1, 2003                             $434,533.06         $3,608,713.77          $4,043,246.83
September 1, 2003                        $375,440.38         $3,667,806.45          $4,043,246.83
December 1, 2003                         $315,380.05         $3,727,866.78          $4,043,246.83
March 1, 2004                            $254,336.23         $3,788,910.60          $4,043,246.83
June 1, 2004                             $192,292.82         $3,850,954.01          $4,043,246.83
September 1, 2004                        $129,233.44         $3,914,013.38          $4,043,246.83
December 1, 2004                         $ 65,141.47         $3,978,105.26          $4,043,246.73
- - -----------------------------------------------------------------------------------------------------
</TABLE>


                                      -6-
<PAGE>   11


         (d) Notwithstanding anything to the contrary contained elsewhere in
this Agreement, (i) all then outstanding principal amount of the Series A Notes
shall be repaid in full on the Series A Maturity Date and (ii) all then
outstanding principal amount of the Series B Notes and the Series C Notes shall
be repaid in full on the Final Maturity Date.

         (e) On the date on which any Change of Control occurs, unless otherwise
agreed by a Purchaser in regard to Notes held by it, the outstanding Notes, if
any, shall become due and payable in full at 100% of the outstanding principal
balance of each Series of Notes plus accrued interest and the Make-Whole Amount.

         (f) Each prepayment of any Series of Notes pursuant to this Section
3.02 shall be applied pro rata among the Purchasers which have outstanding Notes
of such Series.

         3.03 Method and Place of Payment. Except as otherwise specifically
provided herein, all payments under this Agreement shall be made to the
Purchasers (based on their pro rata shares) not later than 1:00 P.M. (New York
time) on the date when due and shall be made in immediately available funds and
in Dollars at the Payment Office, subject to 11.06(b). Any payments under this
Agreement which are made later than 1:00 P.M. (New York time) shall be deemed to
have been made on the next succeeding Business Day. Whenever any payment to be
made hereunder shall be stated to be due on a day which is not a Business Day,
such payment shall instead be made on the immediately succeeding Business Day
without including the days elapsed in the computation of interest payable on
such immediately succeeding Business Day.

         3.04 Net Payments. All payments made by the Company hereunder or under
any Note will be made without setoff, counterclaim or other defense. All such
payments will be made free and clear of, and without deduction or withholding
for, any present or future taxes, levies, imposts, duties, fees, assessments or
other charges of whatever nature now or hereafter imposed by any jurisdiction or
by any political subdivision or taxing authority thereof or therein with respect
to such payments (but excluding, except as provided in the second succeeding
sentence, any tax imposed on or measured by the net income or net profits of a
Purchaser pursuant to the laws of the jurisdiction in which it is organized or
managed and controlled or the jurisdiction in which the principal office or
applicable lending office of such Purchaser is located or any subdivision
thereof or therein) and all interest, penalties or similar liabilities with
respect thereto (all such non-excluded taxes, levies, imposts, duties, fees,
assessments or other charges being referred to collectively as "Taxes"). If any
Taxes are so levied or imposed, the Company agrees to pay the full amount of
such Taxes, and such additional amounts, if any, as may be necessary so that
every payment of all amounts due under this Agreement or under any Note, after
withholding or deduction for or on account of any Taxes, will not be less than
the amount provided for herein or in such Note. If any amounts are payable in
respect of Taxes pursuant to the preceding sentence, the Company agrees to
reimburse each Purchaser, upon the written request of such Purchaser, for taxes
imposed on or measured by the net income or net profits of such Purchaser
pursuant to the laws of the jurisdiction in which 




                                      -7-
<PAGE>   12

the principal office or applicable lending office of such Purchaser is located
or under the laws of any political subdivision or taxing authority of any such
jurisdiction in which the principal office or applicable lending office of such
Purchaser is located and for any withholding of taxes as such Purchaser shall
determine are payable by, or withheld from, such Purchaser in respect of such
amounts so paid to or on behalf of such Purchaser pursuant to the preceding
sentence and in respect of any amounts paid to or on behalf of such Purchaser
pursuant to this sentence. The Company will furnish to the Trustee within 45
days after the date the payment of any Taxes is due pursuant to applicable law
certified copies of tax receipts evidencing such payment by the Company. The
Company agrees to indemnify and hold harmless each Purchaser, and reimburse such
Purchaser upon its written request, for the amount of any Taxes so levied or
imposed and paid by such Purchaser.

        3.05 Purchase of Notes. The Company will not and will not permit any
Affiliate to purchase, redeem, prepay or otherwise acquire, directly or
indirectly, any of the outstanding Notes except upon the payment or prepayment
of the Notes in accordance with the terms of this Agreement and the Notes. The
Company will promptly cancel all Notes acquired by it or any Affiliate pursuant
to any payment, prepayment or purchase of Notes pursuant to any provision of
this Agreement and no Notes may be issued in substitution or exchange for any
such Notes.

SECTION 4.  CONDITIONS PRECEDENT.

         The occurrence of the Effective Date pursuant to Section 11.10 and the
Commitments of the Purchasers to purchase their respective Notes hereunder are
subject to the satisfaction, at the time of the occurrence of each such event,
of each of the following conditions at Closing:

         4.01 Execution of Agreement. (i) The Effective Date shall have occurred
as provided in Section 11.10 and (ii) there shall have been delivered to each
Purchaser the appropriate Note executed by the Company, and in the amount,
maturity and as otherwise provided herein.

         4.02 No Default; Representations and Warranties. On the Drawdown Date,
(i) there shall exist no Default or Event of Default and (ii) all
representations and warranties contained herein or in the other Credit Documents
in effect at such time shall be true and correct in all material respects as
though such representations and warranties were made on the Drawdown Date
(except to the extent that such representations and warranties expressly relate
to the Effective Date, in which case they shall be true and correct in all
material respects as of the Effective Date).

         4.03 Officer's Certificate. On the Effective Date, the Trustee shall
have received a certificate dated such date signed by the President, any Vice
President or the Treasurer of the Company stating that all of the applicable
conditions set forth in Sections 4.02, 4.07, 4.08(a) and 4.09 exist as of such
date.

         4.04 Opinions of Counsel. On the Effective Date, the Trustee shall have
received opinions, addressed to the Trustee and each of the Purchasers and dated
the Effective Date, from (i) Maples and Calder, Cayman Islands counsel to the
Company, which opinion




                                      -8-
<PAGE>   13

shall cover the matters contained in Exhibit B-1, (ii) Thompson & Knight, P.C.,
counsel to the Company, which opinion shall cover the matters contained in
Exhibit B-2, (iii) Watson, Farley & Williams, special maritime counsel to the
Purchasers, covering the matters set forth in Exhibit B-3, (iv) Roy Phillips,
Panamanian counsel to the Company, which opinion shall cover the matters
contained in Exhibit B-4 and (v) White & Case, special counsel to the
Purchasers, which opinion shall cover the matters contained in Exhibit B-5, each
of which opinions shall be in form and substance reasonably satisfactory to the
Purchasers.

         4.05 Corporate Proceedings. (a) On the Effective Date, the Trustee
shall have received from each Credit Party a certificate, dated the Effective
Date, signed by the President, any Vice President, the Treasurer or the
Secretary or other appropriate representative of such Credit Party in the form
of Exhibit D with appropriate insertions and deletions, together with copies of
the certificate of incorporation, memorandum and articles of association,
by-laws, and resolutions, or such other administrative approval, of such Credit
Party referred to in such certificate and all of the foregoing shall be
reasonably satisfactory to the Purchasers.

         (b) On the Effective Date, all corporate and legal proceedings and all
instruments and agreements in connection with the transactions contemplated by
this Agreement and the other Credit Documents shall be reasonably satisfactory
in form and substance to the Purchasers, and each Purchaser shall have received
all information and copies of all certificates, documents and papers, including
good standing certificates and any other records of corporate proceedings and
governmental approvals, if any, which a Purchaser may have reasonably requested
in connection therewith, such documents and papers, where appropriate, to be
certified by proper corporate or governmental authorities.

         4.06 Construction Contract. On or prior to the Effective Date, there
shall have been delivered to the Trustee a copy, certified as true and correct
by an appropriate officer of the Company of the Construction Contract.

         4.07 Adverse Change, etc. On the Effective Date, (a) no Material
Adverse Effect shall have occurred since December 31, 1997 or (b) no Purchaser
shall have become aware of any facts or conditions not previously known which
such Purchaser shall determine in its reasonable business judgment (i) has, or
is reasonably likely to have, a material adverse effect on the rights or
remedies of the Purchasers hereunder or under any other Credit Document, or on
the ability of the Company or the Parent Guarantor to perform their respective
obligations to them, or (ii) has, or is reasonably likely to have, a Material
Adverse Effect.

         4.08 Litigation. On the Effective Date, there shall be no actions,
suits or proceedings pending or threatened (a) with respect to this Agreement or
any other Credit Document or the transactions contemplated hereby or thereby or
(b) which any Purchaser shall determine in its reasonable business judgment is
reasonably likely to (i) have a Material Adverse Effect or (ii) have a material
adverse effect on the rights or remedies of the Purchasers hereunder or under
any other Credit Document or on the ability of the Company or the Parent
Guarantor to perform their respective obligations to the Purchasers hereunder or
under any other Credit Document.


                                      -9-
<PAGE>   14


         4.09 Approvals. On the Effective Date, all necessary governmental and
third party approvals in connection with the transactions contemplated by the
Credit Documents and otherwise referred to herein or therein shall have been
obtained and remain in effect, and all applicable waiting periods shall have
expired without any action being taken by any competent authority which
restrains or prevents such transactions or imposes, in the reasonable business
judgment of any Purchaser, materially adverse conditions upon the consummation
of such transactions.

         4.10 Fees. On the Effective Date, the Company shall have paid to the
Trustee all Fees and expenses (including the fees and expenses of each special
counsel to the Purchasers) agreed upon by such parties to be paid on or prior to
such date.

         4.11 Guaranties. On the Effective Date (i) Parent Guarantor shall have
duly authorized, executed and delivered the Parent Guaranty in the form of
Exhibit D-1 hereto (as modified, amended or supplemented from time to time in
accordance with the terms thereof and hereof, the "Parent Guaranty"), and (ii)
each Subsidiary Guarantor shall have duly authorized, executed and delivered the
Subsidiary Guaranty in the form of Exhibit D-2 hereto (as modified, amended or
supplemented from time to time in accordance with the terms thereof and hereof,
the "Subsidiary Guaranty").

         4.12 Insurance Report. On or prior to the Effective Date, each
Purchaser shall have received a detailed report from Aon Risk Services of Texas,
Inc. or another firm of independent marine insurance brokers reasonably
acceptable to the Purchasers with respect to the insurance maintained in
connection with the Mortgaged Rigs, together with a certificate from such broker
certifying that such insurances are placed with such insurance companies and/or
underwriters and/or clubs, in such amounts, against such risks, and in such
form, as are normally insured against by similarly situated insureds.

         4.13 Assignment of Insurances. On the Effective Date, the Assignments
of Insurances in the form of Exhibit F (as modified, amended or supplemented
from time to time in accordance with the terms thereof and hereof, the
"Assignments of Insurances") shall be in full force and effect.

         4.14 Mortgages. On the Effective Date, mortgages (in each case
substantially in the form of Exhibit G, as modified, amended, or supplemented
from time to time in accordance with the terms thereof and hereof, the
"Mortgages") shall have been executed and delivered to the satisfaction of the
Purchasers with respect to the Vessel, the Noble Leo Segerius registered under
the laws and flag of the Republic of Panama (Official No. 23387-96-B) and the
Noble Roger Eason registered under the laws and flag of the Republic of Panama
(Official No. 23418-97-B) (collectively, including the Vessel, the "Mortgaged
Rigs") and shall otherwise be in full force and effect and all actions
necessary, desirable or otherwise reasonably requested by any Purchaser to
provide the Trustee with a perfected first priority security interest in all
Collateral purported to be covered by the Mortgages shall have been taken.

         4.15 Purchase Permitted By Applicable Law, etc. On the date of the
Closing the purchase of Notes shall (i) be permitted by the laws and regulations
of each jurisdiction to which each Purchaser is subject, without recourse to
provisions (such as Section 1405(a)(8) of the New York Insurance Law) permitting
limited investments by insurance 

                                      -10-
<PAGE>   15

companies without restriction as to the character of the particular investment,
(ii) not violate any applicable law or regulation (including, without
limitation, Regulation T, U or X of the Board of Governors of the Federal
Reserve System) and (iii) not subject such Purchaser to any tax, penalty or
liability under or pursuant to any applicable law or regulation, which law or
regulation was not in effect on the date hereof. If requested by a Purchaser,
such Purchaser shall have received a certificate from one of the officers
specified in Section 4.03 certifying as to such matters of fact as you may
reasonably specify to enable it to determine whether such purchase is so
permitted.

         4.16 Sale of Other Notes. Contemporaneously with the Closing the
Company shall sell to each Purchaser and each Purchaser shall purchase the Notes
to be purchased by it at the Closing as specified in Annex I.

         4.17 Private Placement Number. A Private Placement number issued by
Standard & Poor's CUSIP Service Bureau (in cooperation with the Securities
Valuation Office of the National Association of Insurance Commissioners) shall
have been obtained for the Notes.

The acceptance of the benefits of the Notes shall constitute a representation
and warranty by the Company to the Trustee and each of the Purchasers that all
of the applicable conditions specified above exist as of that time. All of the
certificates, legal opinions and other documents and papers referred to in this
Section 4, unless otherwise specified, shall be delivered at the Closing for the
account of each of the Purchasers and, except for the Notes, in sufficient
counterparts or copies for each of the Purchasers and shall be satisfactory in
form and substance to the Purchasers.

SECTION 5.  REPRESENTATIONS, WARRANTIES AND AGREEMENTS.

         In order to induce the Purchasers to enter into this Agreement and to
purchase the Notes, the Company makes the following representations and
warranties to, and agreements with, the Purchasers and the Trustee, all of which
shall survive the execution and delivery of this Agreement and the purchase of
the Notes:

         5.01 Corporate Status. The Company (i) is a duly organized and validly
existing company in good standing under the laws of the jurisdiction of its
organization and has the corporate power and authority to own its property and
assets and to transact the business in which it is engaged, except in such case
where the failure to be duly organized and validly existing in good standing and
to have such corporate power and authority (x) is not reasonably likely to have
a Material Adverse Effect or (y) is not reasonably likely to have a material
adverse effect on the rights or remedies of the Purchasers or on the ability of
the Company to perform its obligations to them hereunder and under the other
Credit Documents to which it is a party, and (ii) has duly qualified and is
authorized to do business and is in good standing in all jurisdictions where it
is required to be so qualified and where the failure to be so qualified would
have a Material Adverse Effect.

         5.02 Corporate Power and Authority. The Company has the corporate power
and authority to execute, deliver and carry out the terms and provisions of the
Credit Documents to which it is a party and has taken all necessary corporate
action to authorize the execution, delivery and performance of the Credit
Documents to which it is a party. 



                                      -11-
<PAGE>   16

The Company has duly executed and delivered each Credit Document to which it is
a party and each such Credit Document constitutes the legal, valid and binding
obligation of the Company enforceable against the Company in accordance with its
terms, except to the extent that the enforceability thereof may be limited by
applicable bankruptcy, insolvency, reorganization, moratorium or similar laws
generally affecting creditors' rights and by equitable principles (regardless of
whether enforcement is sought in equity or at law).

         5.03 No Violation. Neither the execution, delivery and performance by
the Company of the Credit Documents to which it is a party nor compliance with
the terms and provisions thereof, nor the consummation of the transactions
contemplated therein (i) will contravene any applicable provision of any law,
statute, rule, regulation, order, writ, injunction or decree of any court or
governmental instrumentality of the United States or any State thereof, (ii)
will result in any breach of any of the terms, covenants, conditions or
provisions of, or constitute a default under, or result in the creation or
imposition of (or the obligation to create or impose) any Lien upon any of the
property or assets of the Company pursuant to the terms of, any indenture,
mortgage, deed of trust, agreement or other instrument to which the Company is a
party or by which it or any of its property or assets are bound or to which it
is subject, other than Permitted Liens, or (iii) will violate any provision of
the memorandum and articles of association of the Company.

         5.04 Litigation. There are no actions, suits or proceedings pending or,
to the knowledge of the Company, after due inquiry, threatened with respect to
the Company (i) that are likely to have a Material Adverse Effect or (ii) that
are reasonably likely to have a material adverse effect on the rights or
remedies of the Purchasers or on the ability of the Company to perform its
obligations to them hereunder and under the other Credit Documents to which it
is a party.

         5.05 Use of Proceeds; Margin Regulations. (a) The proceeds of all Notes
shall be used as contemplated by Section 7.05 to fund costs and expenses
incurred by the Company and its Affiliates in connection with the conversion of
the Vessel from a submersible offshore drilling rig to a Noble Drilling
EVA-4000(tm) semisubmersible drilling rig.

         (b) Neither the purchase of any Note hereunder, nor the use of the
proceeds thereof, will violate or be inconsistent with the provisions of
Regulation T, U or X of the Board of Governors of the Federal Reserve System and
no part of the proceeds of any Note will be used to purchase or carry any Margin
Stock in violation of Regulation U or to extend credit for the purpose of
purchasing or carrying any Margin Stock.

         5.06 Governmental Approvals. Except for the orders, consents,
approvals, licenses, authorizations, validations, recordings, registrations and
exemptions that have already been duly made or obtained and remain in full force
and effect, no order, consent, approval, license, authorization, or validation
of, or filing, recording or registration with, or exemption by, any foreign or
domestic governmental or public body or authority, or any subdivision thereof,
is required to authorize or is required in connection with (i) the execution,
delivery and performance of any Credit Document, (ii) the legality, validity,
binding effect or enforceability of any Credit Document or (iii) completion of
the Project.


                                      -12-
<PAGE>   17


         5.07 Investment Company Act. The Company is not an "investment company"
or a company "controlled" by an "investment company," within the meaning of the
Investment Company Act of 1940, as amended.

         5.08 Public Utility Holding Company Act. The Company is not a "holding
company," or a "subsidiary company" of a "holding company," or an "affiliate" of
a "holding company" or of a "subsidiary company" of a "holding company," within
the meaning of the Public Utility Holding Company Act of 1935, as amended.

         5.09 True and Complete Disclosure. All information (taken as a whole)
heretofore or contemporaneously furnished by or on behalf of the Company or its
Affiliates or any agent thereof, including the Arrangers, in writing to any
Purchaser for purposes of or in connection with this Agreement or any
transaction contemplated herein is, and all other such information (taken as a
whole) hereafter furnished by or on behalf of the Company in writing to any
Purchaser will be, true and accurate in all material respects on the date as of
which such information is dated or certified and not incomplete by omitting to
state any material fact necessary to make such information (taken as a whole)
not misleading at such time in light of the circumstances under which such
information was provided. There is no fact known to the Company which is
reasonably likely to have a Material Adverse Effect, which has not been
disclosed herein or in such other documents, certificates and statements
furnished to the Trustee and the Purchasers for use in connection with the
transactions contemplated hereby.

         5.10 Financial Condition. On and as of the Effective Date, on a pro
forma basis after giving effect to all Indebtedness incurred, and to be
incurred, by the Company in connection herewith, (x) the sum of the assets, at a
fair valuation, of the Company will exceed its debts, (y) the Company will not
have incurred or intended to, or believe that it will, incur debts beyond its
ability to pay such debts as such debts mature and (z) the Company will not have
unreasonably small capital with which to conduct its business. Nothing has
occurred since the incorporation of the Company that (x) has had or is
reasonably likely to have a material adverse effect on the rights or remedies of
the Purchasers hereunder or under any other Credit Document, or on the ability
of the Company to perform its obligations to them, or (y) has had or is
reasonably likely to have a Material Adverse Effect. Except for the Intercompany
Notes, there were as of the Effective Date no liabilities or obligations with
respect to the Company of a nature (whether absolute, accrued, contingent or
otherwise and whether or not due) which, either individually or in aggregate,
would be material to the Company.

         5.11 Tax Returns and Payments. The Company has filed all material tax
returns, domestic and foreign, required to be filed by it and has paid all
material taxes and assessments payable by it which have become due, other than
those not yet delinquent and except for those contested in good faith for which
adequate reserves have been provided in accordance with GAAP. The Company has
paid, or has provided adequate reserves (in the good faith judgment of the
management of the Company) for the payment of, all federal, state and foreign
income taxes applicable for all prior fiscal years and for the current fiscal
year to the date hereof.

         5.12 Employee Benefit Plans. (a) Neither the Company nor any ERISA
Affiliate has ever maintained or contributed to (or had an obligation to
contribute to) any Plan or


                                      -13-
<PAGE>   18

any Foreign Pension Plan where any current or reasonably foreseeable liability
of the Company with respect to such Plan or such Foreign Pension Plan would be
reasonably likely to have a Material Adverse Effect. All contributions required
to be made with respect to (i) any employee pension benefit plan (as defined in
Section 3(2) of ERISA) maintained or contributed to by (or to which there is an
obligation to contribute of) the Company or an ERISA Affiliate and (ii) any
Foreign Pension Plan have been timely made except any such failures to
contribute which would not individually or in the aggregate be reasonably likely
to have a Material Adverse Effect. The Company may cease contributions to or
terminate any employee benefit plan (within the meaning of Section 3(3) of
ERISA) maintained or contributed to by (or to which there is an obligation to
contribute of) it without incurring any liability which, individually or in the
aggregate would be reasonably likely to have a Material Adverse Effect.

         (b) Each Foreign Pension Plan has been maintained in substantial
compliance with its terms and with the requirements of any and all applicable
laws, statutes, rules, regulations and orders and has been maintained, where
required, in good standing with applicable regulatory authorities.

         (c) In reliance upon the representations of the Purchasers herein, the
execution and delivery of this Agreement and the issuance and sale of the Notes
hereunder will be exempt from, or will not involve any transaction which is
subject to, the prohibitions of either Section 406 of ERISA or Section 4975 of
the Code and will not involve any transaction in connection with which a penalty
could be imposed under Section 502(i) of ERISA or a tax could be imposed
pursuant to Section 4975 of the Code.

         5.13 Subsidiaries. The Company has no Subsidiaries on the Effective
Date.

         5.14 Patents, etc. The Company has obtained all patents, trademarks,
service marks, trade names, copyrights, licenses and other rights, free from
burdensome restrictions, that are necessary for the operation of its business
taken as a whole as presently conducted, and the Company knows of no such rights
the absence of which would be reasonably likely to have a Material Adverse
Effect.

         5.15 Pollution and Other Regulations. (a) The Company is in compliance
with all applicable Environmental Laws governing its business for which failure
to comply is reasonably likely to have a Material Adverse Effect, and the
Company is not liable for any material penalties, fines or forfeitures for
failure to comply with any of the foregoing. All licenses, permits,
registrations or approvals required for the business of the Company, as
conducted as of the Effective Date, under any Environmental Law have been
secured and the Company is in substantial compliance therewith, except such
licenses, permits, registrations or approvals the failure to secure or to comply
therewith is not likely to have a Material Adverse Effect. The Company is not in
any respect in noncompliance with, breach of or default under any applicable
writ, order, judgment, injunction, or decree to which the Company is a party or
which would affect the ability of the Company to operate the Vessel or facility
owned or operated by the Company and no event has occurred and is continuing
which, with the passage of time or the giving of notice or both, would
constitute noncompliance, breach of or default thereunder, except in each such
case, such noncompliance, breaches or defaults as are not likely to, in the
aggregate, have a Material Adverse Effect. There are as of the Effective Date no
Environmental Claims pending or, 


                                      -14-
<PAGE>   19

to the knowledge, after due inquiry, of the Company, threatened, against the
Company wherein an unfavorable decision, ruling or finding would be reasonably
likely to have a Material Adverse Effect. There are no facts, circumstances,
conditions or occurrences on the Vessel or facility owned or operated by the
Company that is reasonably likely (i) to form the basis of an Environmental
Claim against the Company or the Vessel or facility owned by the Company, or
(ii) to cause the Vessel or facility owned or operated by the Company to be
subject to any restrictions on its ownership, occupancy, use or transferability
under any Environmental Law, except in each such case, such Environmental Claims
or restrictions that individually or in the aggregate are not reasonably likely
to have a Material Adverse Effect.

         (b) Hazardous Materials have not at any time been (i) generated, used,
treated or stored on, or transported to or from, the Vessel or facility at any
time owned or operated by the Company or (ii) released on or from the Vessel or
any such facility, in each case where, to the Company's knowledge, after due
inquiry, such occurrence or event individually or in the aggregate is reasonably
likely to have a Material Adverse Effect.

         5.16 Properties. The Company has title to all material properties owned
by it free and clear of all Liens, other than Permitted Liens.

         5.17 Labor Relations. The Company is not engaged in any unfair labor
practice that is reasonably likely to have a Material Adverse Effect. There is
(i) no unfair labor practice complaint pending against the Company or threatened
against the Company, before the National Labor Relations Board, and no grievance
or arbitration proceeding arising out of or under any collective bargaining
agreement is so pending against the Company or, to the Company's knowledge,
after due inquiry, threatened against any of them, (ii) no strike, labor
dispute, slowdown or stoppage pending against the Company or, to the Company's
knowledge, after due inquiry, threatened against the Company and (iii) no union
representation petition existing with respect to the employees of the Company
and no union organizing activities are taking place, except with respect to any
matter specified in clause (i), (ii) or (iii) above, either individually or in
the aggregate, such as is not reasonably likely to have a Material Adverse
Effect.

         5.18 Existing Indebtedness. The Company has no Indebtedness (other than
the Notes) on the Effective Date.

         5.19 Rig Classification. Each Mortgaged Rig is classified in the
highest class available for rigs of its age and type with the American Bureau of
Shipping, Inc, Bureau Veritas, Det Norske Veritas, Lloyd's Register of Shipping,
or another internationally recognized classification society reasonably
acceptable to the Trustee, free of any material requirements or recommendations,
provided that the Vessel may be out of class as a result of, and pending the
completion of, the Project.

         5.20 Security Interests. On and after the Effective Date, each of the
Security Documents creates, as security for the Obligations purported to be
secured thereby, a valid and enforceable perfected security interest in and Lien
on all of the Collateral subject thereto, to the extent perfection of a security
interest or Lien is governed by Article 8 or Article 9 of the UCC (as defined in
the applicable Security Documents), the Ship Mortgage Act (as defined in the
Mortgages, if any), or comparable provisions under the


                                      -15-
<PAGE>   20
laws of the Republic of Panama, Liberia or any other jurisdiction in which any
Mortgaged Rig is registered, and subject to no other Liens (except that the
Collateral may be subject to Permitted Liens), in favor of the Trustee for the
benefit of the Purchasers. No filings or recordings are required in order to
perfect the security interests created under any Security Document except for
filings or recordings required in connection with any such Security Document
which shall have been made upon or prior to (or are the subject of arrangements,
satisfactory to the Trustee, for filing on or promptly after the date of) the
execution and delivery thereof.

          5.21 Foreign Assets Control Regulations, etc. Neither the sale of the
Notes by the Company hereunder nor its use of the proceeds thereof will violate
the Trading with Enemy Act, as amended, or any of the foreign assets control
regulations of the United States Treasury Department (31 CFR, Subtitle B,
Chapter V, as amended) or any enabling legislation or executive order relating
thereto.

         5.22 Compliance with Laws, etc. The Company is not in violation of (i)
any laws, ordinances, governmental rules or regulations to which it is subject
or by which it or any of its properties might be bound, (ii) any order, judgment
or decree of any court, arbitrator or administrative or governmental body to
which it is subject or by which it or any of its properties might be bound,
(iii) any term of any contract, agreement or other instrument to which it is a
party or by which it or any of its properties might be bound, or (iv) any term
of its memorandum and articles of association; where, in each case, such
violation might reasonably be expected to have a Material Adverse Effect.

         5.23 Offering of the Notes. Neither the Company nor any agent acting on
its behalf has, directly or indirectly, offered the Notes or any similar
security of the Company for sale to, or solicited any offers to buy the Notes or
any similar security of the Company from, or otherwise approached or negotiated
with respect thereto with, any Person other than 22 Institutional Investors, and
neither the Company nor any agent acting on its behalf has taken or will take
any action directly or indirectly, which would require the registration of the
Notes under the provisions of section 5 of the Securities Act of 1933, as
amended, or under the provisions of any securities or Blue Sky law of any
applicable jurisdiction relating to securities offered to the public.

SECTION 6.  AFFIRMATIVE COVENANTS.

         The Company covenants and agrees that on the Effective Date and
thereafter for so long as this Agreement is in effect and until the Notes
(together with interest), Fees and all other Obligations incurred hereunder, are
paid in full:

         6.01 Information Covenants. The Company will furnish to the Trustee
(with sufficient copies for each of the Purchasers, and the Trustee will
promptly forward to each of the Purchasers):

         (a) Notice of Default or Litigation. Promptly, and in any event within
(x) five days after a member of the senior management of the Company obtains
knowledge thereof, notice of the occurrence of any event which constitutes a
Default or Event of Default, which notice shall specify the nature thereof, the
period of existence thereof and what action the Company proposes to take with
respect thereto and (y) ten Business Days




                                      -16-
<PAGE>   21

after a member of the senior management of the Company obtains knowledge
thereof, notice of the commencement of or any significant development in any
litigation or governmental proceeding pending against the Company which is
likely to have a Material Adverse Effect or is likely to have a material adverse
effect on the ability of the Company to perform its obligations hereunder or
under any other Credit Document.

         (b) Other Information. From time to time, such other information or
documents (financial or otherwise) as the Trustee or any Purchaser may
reasonably request.

         6.02 Books, Records and Inspections. The Company will, upon reasonable
notice to the Senior Vice President-Finance, Controller or any other Authorized
Officer of the Company, permit officers and designated representatives of the
Trustee (at the expense of the Trustee, but after the occurrence and during the
continuance of a Default or an Event of Default, at the expense of the Company)
or any Purchaser (at the expense of such Purchaser but after the occurrence and
during the continuance of a Default or an Event of Default at the expense of the
Company), to the extent necessary, to examine the books of account of the
Company and discuss the affairs, finances and accounts of the Company with, and
be advised as to the same by, its and their officers and independent
accountants, all at such reasonable times and intervals and to such reasonable
extent as the Trustee or the Purchaser may desire.
         6.03 Maintenance of Property; Insurance. There will at all times be
maintained on behalf of the Company in full force and effect insurance in such
amounts with carriers of such insurance industry ratings, covering such risks
and liabilities and with such deductibles or self-insured retentions as are in
accordance with normal industry practice for similarly situated insureds.

         6.04 Payment of Taxes. The Company will pay and discharge all taxes,
assessments and governmental charges or levies imposed upon it or upon its
income or profits, or upon any properties belonging to it, prior to the date on
which penalties attach thereto, and all lawful claims which, if unpaid, might
become a Lien or charge upon any properties of the Company, provided that the
Company shall not be required to pay any such tax, assessment, charge, levy or
claim which is being contested in good faith and by proper proceedings if it has
maintained adequate reserves with respect thereto in accordance with GAAP.

         6.05 Consolidated Corporate Franchises. The Company will do all things
necessary to preserve and keep in full force and effect its corporate existence,
material rights and authority, unless the failure to do so is not reasonably
likely to have a Material Adverse Effect, provided that any transaction
permitted by Section 7.02 will not constitute a breach of this Section 6.05.

         6.06 Compliance with Statutes, etc. The Company will comply with all
applicable statutes, regulations and orders of, and all applicable restrictions
imposed by, all governmental bodies, domestic or foreign, in respect of the
conduct of its business and the ownership of its property other than those the
non-compliance with which would not have a Material Adverse Effect or would not
have a material adverse effect on the ability of the Company to perform its
obligations under any Credit Document to which it is party.


                                      -17-
<PAGE>   22


         6.07 Good Repair. Except in the event the Vessel has been damaged or
has suffered a casualty as to which (within a reasonable period of time) the
Company has not made a determination whether to replace or repair, or if the
determination to replace or repair has been made, as to which such replacement
or repairs are being undertaken, subject to availability of equipment, materials
and/or repair facilities, the Company will keep its properties and equipment
used or useful in its business, in whomsoever's possession they may be, in good
repair, working order and condition, normal wear and tear excepted, and, subject
to Section 7.02, see that from time to time there are made in such properties
and equipment all needful and proper repairs, renewals, replacements,
extensions, additions, betterments and improvements thereto, (i) to the extent
and in the manner useful or customary for companies in similar businesses and
(ii) to the extent the failure to do so is reasonably likely to cause a Material
Adverse Effect.

         6.08 End of Fiscal Years; Fiscal Quarters. The Company will, for
financial reporting purposes, cause (i) its fiscal years to end on December 31
of each year and (ii) its fiscal quarters to end on March 31, June 30, September
30 and December 31 of each year.

         6.09 Use of Proceeds. All proceeds of the Notes shall be used as
provided in Section 5.05.

         6.10 ERISA. As soon as possible and, in any event, within 10 days after
the Company or any ERISA Affiliate knows or has reason to know that: (a) a
material contribution required to be made with respect to (i) any employee
pension benefit plan (as defined in Section 3(2) of ERISA) maintained or
contributed to by (or to which there is an obligation to contribute of) the
Company or an ERISA Affiliate or (ii) any Foreign Pension Plan has not been
timely made or (b) the Company may incur any material liability pursuant to any
employee welfare benefit plan (as defined in Section 3(1) of ERISA) that
provides benefits to retired employees or other former employees (other than as
required by Section 601 of ERISA) or any employee pension benefit plan (as
defined in Section 3(2) of ERISA), the Company will deliver to each of the
Purchasers a certificate of the Senior Vice President-Finance or Controller of
the Company setting forth details as to such occurrence and the action, if any,
that the Company or such ERISA Affiliate is required or proposes to take,
together with any notices required or proposed to be given to or filed with or
by the Company, the ERISA Affiliate, a plan participant or the plan
administrator.

         6.11 Earnings Concentration Account. Noble Drilling (Nederland) B.V.
("NDNBV") as contractor under the Petrobas Contract, and/or, following any
assignment or transfer of the Petrobras Contract as contemplated in Section
6.12(d), the Company, shall maintain with the Trustee a trust account (the
"Concentration Account"), as provided in Section 10.10. NDNBV and/or the
Company, as appropriate, shall cause all payments made under the Petrobras
Contract to be deposited into the Concentration Account. Until the Company or
any Purchaser has given the Trustee notice, pursuant to Section 10.12, of the
occurrence of a Default or an Event of Default, any and all funds in the
Concentration Account may from time to time be freely disbursed to NDNBV or the
Company as provided in Section 10.10. Following the occurrence of a Default or
an Event of Default, neither NDNBV nor the Company shall have any right to
receive funds from the


                                      -18-
<PAGE>   23

Concentration Account, and such funds shall be held by the Trustee as security
or applied to the outstanding Obligations as Required Purchasers may direct.

         6.12 Further Assurances. (a) The Company will at the
expense of the Company, make, execute, endorse, acknowledge, file and/or deliver
to the Trustee, from time to time such vouchers, invoices, schedules,
confirmatory assignments, conveyances, financing statements, transfer
endorsements, power of attorney, certificates, real property surveys, reports
and other assurances or instruments and take such further steps relating to the
Collateral as the Trustee or any Purchaser may reasonably require.

         (b) The Company agrees that each action required
above by this Section 6.12 shall be completed as soon as possible, but in no
event later than 60 days after such action is requested to be taken by the
Trustee or the Required Purchasers, provided that in no event shall the Company
be required to take action, other than using its reasonable commercial efforts,
to obtain consents or other actions from third parties with respect to its
compliance with this Section 6.12

         (c) The Trustee hereby agrees that, so long as there
exists no Default or Event of Default, it will, after written notification from
the Company of the occurrence of the Project Completion Date, upon the request
of and at the expense of the Company, release, from the respective Mortgages
each Mortgaged Rig other than the Vessel (collectively, the "Pre-Delivery
Mortgaged Rigs") and release Noble Asset Company Limited ("NACL") from the
Subsidiary Guaranty, whereafter NACL shall have no further obligation with
respect to the security interests theretofore maintained for the benefit of the
Secured Creditors in such rigs and the insurances thereon or its guaranty under
such Subsidiary Guaranty.

         (d) The Purchasers and the Trustee hereby
acknowledge and agree that following the Effective Date NDNBV may assign or
otherwise transfer the Petrobras Contract (subject to the prior written
authorization of the counterparty thereunder as set forth therein) and its right
to receive funds from the Concentration Account to the Company. Following any
such assignment or transfer, and so long as there exists no Default or Event of
Default, the Trustee will, upon the request of and at the expense of the
Company, release NDNBV from the Subsidiary Guaranty, whereafter NDNBV shall have
no further obligation with respect to its guaranty under such Subsidiary
Guaranty.

         6.13  Nature of Business.  The Company shall:

                  (i) do all such things as are necessary to maintain its
corporate existence, except this paragraph shall not prevent the Company from
entering into any transaction permitted by Section 7.02;

                  (ii) ensure that it has the right and is duly qualified to
conduct its business as it is conducted in all applicable jurisdictions and will
obtain and maintain all rights necessary for the conduct of its business, except
where such failure to do so could reasonably be expected to not result in a
Material Adverse Effect;

                  (iii)at all times comply with all laws and with all rules,
regulations and orders made by any governmental authority applicable to it or to
any or all of its property,



                                      -19-
<PAGE>   24

except for those being contested in good faith by appropriate proceedings and
except where such failure to do so could reasonably be expected to not result in
a Material Adverse Effect; and

                  (iv) own or have a leasehold interest in all of its property,
except where the failure to do so could reasonably be expected to not result in
a Material Adverse Effect.

SECTION 7.  NEGATIVE COVENANTS.

         The Company hereby covenants and agrees that as of the Effective Date
and thereafter for so long as this Agreement is in effect and until the Notes
(together with interest), Fees and all other Obligations incurred hereunder, are
paid in full:

         7.01 Changes in Business. The Company will not materially alter the
character of its business taken as a whole from that conducted at the Effective
Date.

         7.02 Consolidation, Merger, Sale of Assets, etc. The Company will not
wind up, liquidate or dissolve its affairs, or enter into any transaction of
merger or consolidation, sell or otherwise dispose of all or any part of its
property or assets, including the Vessel (other than inventory or obsolete
equipment or excess equipment no longer needed in the conduct of the business in
the ordinary course of business) or agree to do any of the foregoing at any
future time, except that the following shall be permitted:

         (a) the Company may be merged or consolidated with or into, or be
liquidated into, the Parent Guarantor; provided, however, that the Parent
Guarantor shall have assumed the obligations of the Company hereunder in writing
and shall have delivered to the Trustee an opinion of counsel to the effect that
the obligations of the Company have been duly and validly assumed and constitute
valid and binding obligations of the Parent Guarantor enforceable against Parant
Guarantor in accordance with its terms.

         (b)  Restricted Payments permitted pursuant to Section 7.05; and

         (c) so long as no Default or Event of Default exists or would result
therefrom, the Company may, on or after June 1, 2001, sell or dispose of the
Vessel ,provided that the Company shall prepay the Notes in full with the
proceeds of such sale or disposition or otherwise pursuant to Section 3.01.

         7.03 Indebtedness. The Company will not contract, create, incur, assume
or suffer to exist any Indebtedness, except:

         (a) Indebtedness incurred pursuant to this Agreement and the other
Credit Documents; and

         (b) Indebtedness (i) of not to exceed $10,000,000 in the aggregate
outstanding at any one time owed to the Parent Guarantor incurred in connection
with working capital advances for operation of the Vessel, (ii) owed to the
Parent Guarantor for advances for repairs to the Vessel or (iii) owed to the
Parent Guarantor for advances for upgrades to the Vessel, in each case to the
extent such Indebtedness is subordinated to the obligations



                                      -20-
<PAGE>   25

of the Company hereunder on terms of subordination approved by the Required
Purchasers.

         7.04 Liens. The Company will not create, incur, assume or suffer to
exist any Lien upon or with respect to any property or assets (real or personal,
tangible or intangible) of the Company, whether now owned or hereafter acquired
or sell any such property or assets subject to an understanding or agreement,
contingent or otherwise, to repurchase such property or assets (including sales
of accounts receivable or notes with recourse to the Company) or assign any
right to receive income, or file or permit the filing of any financing statement
under the UCC or any other similar notice of Lien under any similar recording or
notice statute, except:

         (a) Liens for taxes not yet due or Liens for taxes being contested in
good faith and by appropriate proceedings for which adequate reserves (in the
good faith judgment of the management of the Company) have been established;

         (b) Liens imposed by law or arising by operation of law which were
incurred in the ordinary course of business, such as carriers', warehousemen's
and mechanics' Liens, statutory landlord's Liens, maritime Liens and other
similar Liens arising in the ordinary course of business, and (x) which do not
in the aggregate materially detract from the value of the Company's property or
assets or materially impair the use thereof in the operation of the business of
the Company or (y) which are being contested in good faith by appropriate
proceedings (including the providing of bail), which proceedings have the effect
of preventing the forfeiture or sale of the property or assets subject to such
Lien or procuring the release of the property or assets subject to such Lien
from arrest or detention; and (z) in each case not incurred or made, as the case
may be, in connection with (i) the borrowing of money, (ii) the obtaining of
advances or credit or (iii) the payment of deferred purchase price of property
pursuant to the Credit Documents;

         (c)  Liens created in favor of the Purchasers;

         (d) Liens arising from judgments, decrees or attachments (or securing
of appeal bonds with respect thereto) to the extent not covered by insurance
(or, if insured, only to the extent the insurer has admitted coverage in
writing), so long as the obligations in connection therewith do not exceed
$5,000,000 in the aggregate and otherwise in circumstances not constituting an
Event of Default under Section 8.07;

         (e) any interest or title of a lessor or charterer under any lease
permitted by this Agreement;

         (f) immaterial Liens on any assets of the Company other than the
Collateral, so long as the obligations in connection therewith do not exceed
$500,000 in the aggregate;

         (g) Liens (other than any Lien imposed by ERISA) incurred or deposits
made in the ordinary course of business consistent with past practices and
securing obligations not to exceed $5,000,000 in the aggregate (i) in connection
with workers' compensation, unemployment insurance and other types of social
security or retirement benefits, or (ii) to secure the performance of tenders,
statutory obligations, surety bonds, appeal bonds, bids, leases (other than
Capital Leases), performance bonds, purchase, construction or sales 




                                      -21-
<PAGE>   26

contracts and other similar obligations, in each case not incurred or made, as
the case may be, in connection with (x) the borrowing of money, (y) the
obtaining of advances or credit or (z) the payment of the deferred purchase
price of property;

         (h) leases or subleases granted to others, easements, rights-of-way,
restrictions and other similar charges, encumbrances or minor title defects, in
each case incidental to, and not interfering with, or reasonably likely to
interfere with, the ordinary conduct of the business of the Company; or

         (i) Liens on the Vessel arising in connection with the Construction
Contract prior to the Project Completion Date or, after the Project Completion
Date, Liens on the Vessel arising from repairs, to the extent payments therefor
are not delinquent and further to the extent that of 100% of the costs of such
repairs are insured and the insurer has admitted coverage in writing.

         7.05 Restricted Payments. The Company will not make any Restricted
Payments, except:

         (a) On the Drawdown Date, the Company shall repay First Intercompany
Note, the Second Intercompany Note and the Third Intercompany Note in each case
in an amount equal to the outstanding balance thereunder.

         (b) On or after the later of the Drawdown Date or July 1, 1998, the
Company may lend the remaining proceeds of the Notes after repayment in full of
all Intercompany Notes pursuant to clause (a) above to Noble Drilling (U.S.)
Inc. ("NDUS") in exchange for an intercompany note (the "NDUS Note") to be
amortized either in the form of cash payments to the Company or in the form of
payments made by NDUS pursuant to the Project provided the Company shall be in
compliance with Section 7.03.

         (c) So long as no Default or Event of Default exists or would result
therefrom, to the extent the Company is the beneficial owner of the funds in the
Concentration Account, the Company may pay Dividends to its parent with any
funds in such Concentration Account.

         7.06 Restrictions on Subsidiaries. The Company shall not create any
Subsidiaries.

         7.07 Transactions with Affiliates. (a) The Company will not transfer
the Vessel to any Affiliate or enter into any transaction or series of
transactions after the Effective Date whether or not in the ordinary course of
business, with any Affiliate other than on terms and conditions as favorable to
the Company as would be obtainable by the Company at the time in a comparable
arm's-length transaction with a Person other than an Affiliate, provided that
the foregoing restrictions shall not apply to (i) employment arrangements
entered into in the ordinary course of business with officers of the Company,
(ii) customary fees paid to members of the Board of Directors of the Company,
(iii) the repayment by the Company of the Intercompany Notes or (iv) lending
funds to NDUS pursuant to the NDUS Note.



                                      -22-
<PAGE>   27


         7.08 Vessel Management. The Company shall not contract out the
management of the Vessel except to an Affiliate.

SECTION 8.  EVENTS OF DEFAULT.

         Upon the occurrence of any of the following specified events (each an
"Event of Default"):

         8.01 Payments. The Company shall (a) default in the payment when due of
any principal of the Notes or any Make-Whole Amount or (b) default in the
payment when due, and such default shall continue for more than five Business
Days, of any interest, Fees or other amounts owing hereunder or under any other
Credit Document; or

         8.02 Representations, etc. Any representation, warranty or statement
made by Parent Guarantor or the Company in any Credit Document or in any
statement or certificate delivered or required to be delivered pursuant hereto
or thereto shall prove to be untrue in any material respect on the date as of
which made or deemed made; or

         8.03 Covenants. The Company shall (a) default in the due performance or
observance by it of any term, covenant or agreement contained in Section 6.08 or
Section 7 or (b) default in the due performance or observance by it of any term,
covenant or agreement (other than those referred to in Section 8.01, 8.02 or
clause (a) of this Section 8.03) contained in this Agreement or the Mortgage on
the Vessel and such default shall continue unremedied for a period of at least
30 days after the earlier of the date on which an officer of the Company has
actual knowledge thereof or the date of notice to the Company by the Trustee or
any Purchaser; or

         8.04 Default Under Other Agreements. Parent Guarantor or any of its
Subsidiaries shall (i) default in any payment with respect to any Indebtedness
(other than the Obligations) beyond the period of grace, if any, applicable
thereto or (ii) default in the observance or performance of any agreement or
condition relating to any such Indebtedness or contained in any instrument or
agreement evidencing, securing or relating thereto, or any other event shall
occur or condition exist, the effect of which default or other event or
condition is to cause, or to permit the holder or holders of such Indebtedness
(or a trustee or agent on behalf of such holder or holders) to cause any such
Indebtedness to become due prior to its stated maturity; or (b) any such
Indebtedness of Parent Guarantor or any of its Subsidiaries shall be declared to
be due and payable, or required to be prepaid other than by a regularly
scheduled required prepayment, prior to the stated maturity thereof, provided
that it shall not constitute an Event of Default pursuant to this Section 8.04
unless the aggregate amount of all Indebtedness referred to in clauses (a) and
(b) above with respect to Parent Guarantor and its Subsidiaries that is recourse
to the Parent Guarantor, or any Subsidiary of the Parent Guarantor, other than
the obligor thereunder exceeds $25,000,000 at any one time; or

         8.05 Bankruptcy, etc. The Parent Guarantor or any of its Subsidiaries
(other than an Insignificant Subsidiary) shall commence a voluntary case
concerning itself under Title 7 or 11 of the United States Code entitled
"Bankruptcy", as now or hereafter in effect, or any successor thereto (the
"Bankruptcy Code"); or an involuntary case is commenced against the Parent
Guarantor or any of its Subsidiaries (other than an Insignificant Subsidiary)
and the petition is not controverted within 10 days, or is not dismissed within
60 days, after commencement of the case; or a custodian (as defined in the
Bankruptcy Code) is appointed for, or takes charge of, all or substantially all
of the property of the Parent Guarantor or any of its Subsidiaries (other than
an Insignificant Subsidiary); or the Parent Guarantor or any of its Subsidiaries
(other than an Insignificant 



                                      -23-
<PAGE>   28

Subsidiary) commences any other proceeding under any reorganization,
arrangement, adjustment of debt, relief of debtors, dissolution, insolvency or
liquidation or similar law of any jurisdiction whether now or hereafter in
effect relating to the Parent Guarantor or any of its Subsidiaries (other than
an Insignificant Subsidiary); or there is commenced against the Parent Guarantor
or any of its Subsidiaries (other than an Insignificant Subsidiary) any such
case or proceeding which remains undismissed for a period of 60 days; or the
Parent Guarantor or any of its Subsidiaries (other than an Insignificant
Subsidiary) is adjudicated insolvent or bankrupt; or any order of relief or
other order approving any such case or proceeding is entered; the Parent
Guarantor or any of its Subsidiaries (other than an Insignificant Subsidiary)
suffers any appointment of any custodian or the like for it or any substantial
part of its property to continue undischarged or unstayed for a period of 60
days; or the Parent Guarantor or any of its Subsidiaries (other than an
Insignificant Subsidiary) makes a general assignment for the benefit of
creditors; or any corporate action is taken by the Parent Guarantor or any of
its Subsidiaries (other than an Insignificant Subsidiary) for the purpose of
effecting any of the foregoing; or

         8.06 Parent Guaranty. The Parent Guaranty or any provision thereof
shall cease to be in full force and effect, or the Parent Guarantor or any
Person acting by or on behalf of the Parent Guarantor shall deny or disaffirm
all or any portion of the Parent Guarantor's obligation thereunder, or the
Parent Guarantor shall (i) default in the observance of any term, covenant or
agreement contained in Sections 11(g) or 12 of the Parent Guaranty or in the
obligation to make any payment thereunder or (ii) default in the observance of
any other term, covenant or agreement contained in the Parent Guaranty and such
default shall continue unremedied for a period of at least 30 days after the
earlier of the date on which an officer of the Parent Guarantor has actual
knowledge thereof or the date of notice to the Parent Guarantor or the Company
by the Trustee or any Purchaser; or

         8.07 Judgments. One or more judgments or decrees shall be entered
against the Parent Guarantor or any of its Subsidiaries involving a liability of
$25,000,000 or more in the aggregate for all such judgments and decrees (not
paid or to the extent not covered by insurance or, if insured, only to the
extent the insurer has admitted coverage in writing) and any such judgments or
decrees shall not have been vacated, discharged or stayed or bonded pending
appeal within 60 days from the entry thereof; or

         8.08 Employee Benefit Plans. Each of the following shall occur: (a)(i)
A contribution required to be made with respect to any (x) employee pension
benefit plan (as defined in Section 3(2) of ERISA) maintained or contributed to
by (or to which there is an obligation to contribute of) the Parent Guarantor,
any of its Subsidiaries or an ERISA Affiliate or (y) Foreign Pension Plan has
not been timely made or (ii) the Parent Guarantor or any of its Subsidiaries has
incurred or is likely to incur liabilities pursuant to one or more employee
welfare benefit plans (as defined in Section 3(1) of ERISA) that provide
benefits to retired employees or other former employees (other than as required
by Section



                                      -24-
<PAGE>   29

601 of ERISA) or employee pension benefit plans (as defined in Section 3(2) of
ERISA); and (b) there shall result from any such event or events the imposition
of a Lien, the granting of a security interest, or a liability or a material
risk of incurring a liability; and (c) such Lien, security interest or
liability, individually or in the aggregate when combined with all other such
Liens, security interests or liabilities, will, in the opinion of the Required
Purchasers, have a Material Adverse Effect; or

         8.09  Change of Control.  Any Change of Control shall occur; or

         8.10 Vessel in Class. Any insurance required to be maintained by the
terms of the Mortgages shall cease to be in full force and effect or, at any
time after the Project Completion Date the Vessel no longer is classified in the
highest class available for rigs of its age and type with the American Bureau of
Shipping, Inc., Bureau Veritas, Det Norske Veritas, Lloyd's Register of
Shipping, or another internationally recognized classification society
reasonably acceptable to the Purchasers;

then, and in any such event, and at any time thereafter, if any Event of Default
shall then be continuing, the Trustee shall, upon the written request of the
Required Purchasers, by written notice to the Company, take any or all of the
following actions, without prejudice to the rights of the Trustee or any
Purchaser to enforce its claims against the Company , except as otherwise
specifically provided for in this Agreement (provided that, if an Event of
Default specified in Section 8.05 shall occur with respect to Parent Guarantor
or any of its Subsidiaries (other than an Insignificant Subsidiary), the result
which would occur upon the giving of written notice by the Trustee as specified
in clauses (i) and (ii) below shall occur automatically without the giving of
any such notice): (i) declare the Notes and all Obligations owing hereunder to
be due, whereupon the same shall become, forthwith due and payable in the full
at 100% of the outstanding principal balance of the respective Series of Notes
plus accrued interest and the Make-Whole Amount without presentment, demand,
protest or other notice of any kind, all of which are hereby waived by the
Company; (ii) declare any other obligations owing hereunder to be due, whereupon
the same shall become, forthwith due and payable without presentment, demand,
protest or other notice of any kind, all of which are hereby waived by the
Company; (iii) apply any amounts held as cash collateral to repay Obligations,
and (iv) exercise all available rights and remedies under the Mortgage.
Notwithstanding the foregoing, nothing herein shall impair the right of any
Purchaser to accelerate its own Notes if an Event of Default under Section 8.01
shall occur and be continuing.

SECTION 9.  DEFINITIONS.

         As used herein, the following terms shall have the meanings herein
specified unless the context otherwise requires. Defined terms in this Agreement
shall include in the singular number the plural and in the plural the singular:

         "Affiliate" shall mean, with respect to any Person, any other Person
directly or indirectly controlling (including but not limited to all directors
and officers of such Person), controlled by, or under direct or indirect common
control with such Person. A Person shall be deemed to control (x) a corporation
if such Person possesses, directly or indirectly, the power (i) to vote 25% or
more of the securities having ordinary voting power for the election of
directors of such corporation or (ii) to direct or cause the 


                                      -25-
<PAGE>   30

direction of the management and policies of such corporation, whether through
the ownership of voting securities, by contract or otherwise or (y) any
partnership, association joint venture, limited liability company or other
entity in which such person, directly or indirectly through one or more
subsidiaries, has more than a 25% equity interest.

         "Agreement" shall mean this Note Purchase Agreement, as the same may be
from time to time further modified, amended and/or supplemented.

         "Approved Bank" shall have the meaning provided in the definition of
"Cash Equivalents."

         "Approved Company" shall have the meaning provided in the definition of
"Cash Equivalents."

         "Arrangers" shall mean Christiania Bank og Kreditkasse ASA, New York
Banch and Kramer, Clark & Company, Inc.

         "Assignments of Insurances" shall mean the Assignments of Insurances
substantially in the form of Exhibit F.

         "Authorized Officer" shall mean any senior officer of the Company
designated as such in writing to the Trustee by the Company.

         "Bankruptcy Code" shall have the meaning provided in Section 8.05.

         "Business Day" shall mean any day excluding Saturday, Sunday and any
day which shall be in the City of New York a legal holiday or a day on which
banking institutions are authorized by law or other governmental actions to
close.

         "Capital Lease" as applied to any Person shall mean any lease of any
property (whether real, personal or mixed) by that Person as lessee which, in
conformity with GAAP, is accounted for as a capital lease on the balance sheet
of that Person.

         "Capitalized Lease Obligations" shall mean all obligations under
Capital Leases of the Company in each case taken at the amount thereof accounted
for as liabilities in accordance with GAAP

         "Cash Equivalents" shall mean (i) securities issued or directly and
fully guaranteed or insured by the United States of America or any agency or
instrumentality thereof (provided that the full faith and credit of the United
States of America is pledged in support thereof) having maturities of not more
than four years from the date of acquisition, or repurchase obligations with
respect thereto, (ii) U.S. dollar denominated time deposits, certificates of
deposit, bankers' acceptances and Eurocurrency deposits of (x) any Purchaser,
(y) any domestic commercial bank of recognized standing having capital and
surplus in excess of $100,000,000 or (z) any bank (or the parent company of such
bank) whose short-term commercial paper rating from Standard & Poor's Rating
Group ("S&P") is at least A-1 or the equivalent thereof or from Moody's
Investors Service, Inc. ("Moody's") is at least P-1 or the equivalent thereof
(any such bank, an "Approved Bank"), in each case with maturities of not more
than one year from the date


                                      -26-
<PAGE>   31

of acquisition, (iii) repurchase obligations with a term of not more than seven
days for underlying securities of the types described in clause (i) above
entered into with any bank meeting the qualifications specified in clause (ii)
above, (iv) commercial paper issued by any Purchaser or Approved Bank or by the
parent company of any Purchaser or Approved Bank and commercial paper issued by,
or guaranteed by, any corporation with a short-term commercial paper rating of
at least A-1 or the equivalent thereof by S&P or at least P-1 or the equivalent
thereof by Moody's (any such company, an "Approved Company"), or guaranteed by
any industrial company with a long term unsecured debt rating of at least A or
A2, or the equivalent of each thereof, from S&P or Moody's, as the case may be,
and in each case maturing within one year after the date of acquisition and (v)
investments in money market mutual funds having assets in excess of
$100,000,000.

         "CERCLA" shall mean the Comprehensive Environmental Response,
Compensation, and Liability Act of 1980, as amended, 42 U.S.C. ss. 9601 et seq.

         "Change of Control" shall mean (a) Parent Guarantor shall at any time
cease to own, either directly or indirectly, 100% of the capital stock of the
Company or (b) any "person" (as such term is used in Sections 13(d) and 14(d) of
the Securities Exchange Act of 1934, as amended), is or becomes the beneficial
owner (as defined in Rules 13d-3 and 13d-5 under said Exchange Act), directly or
indirectly, of more than 50% of the total voting power of the Voting Stock of
Parent Guarantor or (c) during any period of two consecutive years, individuals
who at the beginning of such period constituted the Board of Directors of the
Company (together with any new directors whose election by such Board of
Directors or whose nomination for election by the stockholders of the Company
was approved by a vote of a majority of the directors of the Company then still
in office who were either directors at the beginning of such period or whose
election or nomination for election was previously so approved) cease for any
reason to constitute a majority of the Board of Directors of the Company then in
office.

         "Claims" shall have the meaning provided in the definition of
"Environmental Claims."

         "Closing" shall have the meaning provided in Section 1.02.

         "Code" shall mean the Internal Revenue Code of 1986, as amended from
time to time and the regulations promulgated and the rulings issued thereunder.
Section references to the Code are to the Code, as in effect on the Effective
Date and any subsequent provisions of the Code, amendatory thereof, supplemental
thereto or substituted therefor.

         "Collateral" shall mean cash in the Concentration Account, the
Assignments of Insurances and the Mortgaged Rigs and the proceeds of each
thereof.

         "Commitment" shall mean, with respect to each Purchaser, the sum of
such Purchaser's Series A Commitment, Series B Commitment and Series C
Commitment.

         "Company" shall have the meaning provided in the first paragraph of
this Agreement.


                                      -27-
<PAGE>   32


         "Confidential Information" shall have the meaning provided in Section
11.15.

         "Concentration Account" shall have the meaning provided in Section
6.11.

         "Construction Contract" shall mean the Agreement for the
Semi-Submersible Conversion of the Mobile Offshore Drilling Unit "Paul Wolff",
dated June 30, 1997, between NDUS, an Affiliate of the Company, and TDI Halter,
Inc., relating to the Project.

         "Credit Documents" shall mean this Agreement, the Notes, the Mortgages,
the Assignments of Insurances, the Parent Guaranty, each Subsidiary Guaranty and
any documents executed in connection herewith and therewith.

         "Credit Party" shall mean Parent Guarantor, each Subsidiary Guarantor
and the Company.

         "Default" shall mean any event, act or condition which with notice or
lapse of time, or both, would constitute an Event of Default.

         "Dividends" shall mean to declare or pay on the part of the Company any
dividends (other than dividends payable solely in capital stock of such Person)
or return any capital to, its stockholders or authorize or make any other
distribution, payment or delivery of property or cash to its stockholders as
such, or redeem, retire, purchase or otherwise acquire, directly or indirectly,
for a consideration, any shares of any class of its capital stock now or
hereafter outstanding (or any warrants for or options or stock appreciation
rights in respect of any of such shares), or set aside any funds for any of the
foregoing purposes.

         "Dollars" shall mean freely transferable lawful money of the United
States.

         "Drawdown Date" shall mean the date upon which the Notes are purchased
by the Purchasers and the proceeds thereof made available to the Company and
shall be the Effective Date.

         "Effective Date" shall have the meaning provided in Section 11.10.

         "Eligible Transferee" shall mean and include a commercial bank,
financial institution or other "accredited investor" (as defined by Regulation D
of the Securities Act of 1933).

         "Environmental Claims" means any and all administrative, regulatory or
judicial actions, suits, demands, demand letters, claims, liens, notices of
noncompliance or violation, investigations (other than internal reports prepared
by the Company solely in the ordinary course of such Person's business and not
in response to any third party action or request of any kind) or proceedings
relating in any way to any Environmental Law or any permit issued, or any
approval given, under any such Environmental Law (hereafter, "Claims"),
including, without limitation, (a) any and all Claims by governmental or
regulatory authorities for enforcement, cleanup, removal, response, remedial or
other actions or damages pursuant to any applicable Environmental Law, and (b)
any and all Claims by any third party seeking damages, contribution,
indemnification, cost recovery,

                                      -28-
<PAGE>   33

compensation or injunctive relief resulting from Hazardous Materials arising
from alleged injury or threat of injury to health, safety or the environment.

         "Environmental Law" means any applicable Federal, state, foreign or
local statute, law, rule, regulation, ordinance, code, guide, policy and rule of
common law now or hereafter in effect and in each case as amended, and any
judicial or administrative interpretation thereof, including any judicial or
administrative order, consent decree or judgment, relating to the environment,
or Hazardous Materials, including, without limitation, CERCLA; RCRA; the Federal
Water Pollution Control Act, as amended, 33 U.S.C. ss. 1251 et seq.; the Toxic
Substances Control Act, 15 U.S.C. ss. 7401 et seq.; the Clean Air Act, 42 U.S.C.
ss. 7401 et seq.; the Safe Drinking Water Act, 42 U.S.C. ss. 3808 et seq.; the
Oil Pollution Act of 1990, 33 U.S.C. ss. 2701 et seq. and any applicable state
and local or foreign counterparts or equivalents.

         "ERISA" shall mean the Employee Retirement Income Security Act of 1974,
as amended from time to time, and the regulations promulgated and rulings issued
thereunder. Section references to ERISA are to ERISA, as in effect at the
Effective Date and any subsequent provisions of ERISA, amendatory thereof,
supplemental thereto or substituted therefor.

         "ERISA Affiliate" shall mean each person (as defined in Section 3(9) of
ERISA) which together with the Parent Guarantor or any of its Subsidiaries would
be deemed to be a "single employer" (i) within the meaning of Sections 414(b),
(c), (m) and (o) of the Code or (ii) as a result of the Company being or having
been a general partner of such person.

         "Event of Default" shall have the meaning provided in Section 8.

         "Fees" shall mean all amounts payable pursuant to, or referred to in,
Section 2.01.

         "Final Maturity Date" shall mean December 1, 2004.

         "First Intercompany Note" shall mean the Promissory Note, dated May 27,
1998, made by the Company and payable to the order of Noble Drilling (U.S.) Inc.
in the original principal amount of $77,889,000.

         "Foreign Pension Plan" means any plan, fund (including, without
limitation, any superannuation fund) or other similar program established or
maintained outside the United States of America by the Company primarily for the
benefit of employees of the Company residing outside the United States of
America, which plan, fund or other similar program provides, or results in,
retirement income, a deferral of income in contemplation of retirement or
payments to be made upon termination of employment, and which plan is not
subject to ERISA or the Code.

         "GAAP" shall mean generally accepted accounting principles in the
United States of America as in effect from time to time.

         "Hazardous Materials" means (a) any petroleum or petroleum products,
radioactive materials, asbestos in any form that is or could become friable,
urea


                                      -29-
<PAGE>   34

formaldehyde foam insulation, transformers or other equipment that contained
electric fluid containing levels of polychlorinated biphenyls, and radon gas;
(b) any chemicals, materials or substances defined as or included in the
definition of "hazardous substances," "hazardous waste," "hazardous materials,"
"extremely hazardous waste," "restricted hazardous waste," "toxic substances,"
"toxic pollutants," "contaminants," or "pollutants," or words of similar import,
under any applicable Environmental Law; and (c) any other chemical, material or
substance, exposure to which is prohibited, limited or regulated by any
governmental authority.

         "Indebtedness" of any Person shall mean without duplication (i) all
indebtedness of such Person for borrowed money, (ii) the deferred purchase price
of assets or services which in accordance with GAAP would be shown on the
liability side of the balance sheet of such Person, (iii) the face amount of all
letters of credit issued for the account of such Person and, without
duplication, all drafts drawn thereunder, (iv) all Indebtedness of a second
Person secured by any Lien on any property owned by such first Person, whether
or not such indebtedness has been assumed, (v) all Capitalized Lease Obligations
of such Person, (vi) all net obligations of such Person under Interest Rate
Agreements and (vii) all Contingent Obligations (as defined in the Parent
Guaranty) of such Person (other than such Contingent Obligations arising from
the guaranty by such Person of Permitted Indebtedness of the Company and/or its
Subsidiaries) provided that Indebtedness shall not include trade payables and
accrued expenses, in each case arising in the ordinary course of business.

         "Insignificant Subsidiary" shall mean any Subsidiary of the Parent
Guarantor which has assets of not greater than $5,000,000 in the aggregate and
which, if aggregated with all other Subsidiaries of the Parent Guarantor with
respect to which an event described in Section 8.05 has occurred and is
continuing, would have assets of not greater than $25,000,000.

         "Institutional Investor" shall mean (a) any original purchaser of a
Note, (b) any holder of a Note holding more than 4% of the aggregate principal
amount of the Notes then outstanding, and (c) any bank, trust company, savings
and loan association or other financial institution, any pension plan, any
investment company, any insurance company, any broker or dealer, or any other
similar financial institution or entity, regardless of legal form.

         "Intercompany Notes" shall mean, collectively, the First Intercompany
Note, the Second Intercompany Note and the Third Intercompany Note.

         "Interest Rate Agreement" shall mean any interest rate swap agreement,
any interest rate cap agreement, any interest rate collar agreement or other
similar agreement or arrangement designed to protect the Company against
interest rate risk.

         "Investments" shall mean and include (i) lending money or credit or
making advances to any Person (net of any repayments or returns thereof), (ii)
purchasing or acquiring any stock, obligations or securities of, or any other
interest in, or making capital contributions to any Person, or (iii)
guaranteeing the debt or obligations of any other Person.



                                      -30-
<PAGE>   35

         "Lien" shall mean any mortgage, pledge, security interest, security
title, encumbrance, lien or charge of any kind (including any agreement to give
any of the foregoing, any conditional sale or other title retention agreement or
any lease in the nature thereof).

         "Make-Whole Amount" shall have the meaning provided in Section 3.01(b).

         "Margin Stock" shall have the meaning provided in Regulation U.

         "Material Adverse Effect" shall mean a material adverse effect on (a)
the business, operations, affairs, financial condition, assets or properties of
the Company or the Parent Guarantor and its Subsidiaries taken as a whole, or
(b) the ability of the Company to perform its obligations under this Agreement
and the Notes, or the ability of the Parent Guarantor to perform its obligations
under the Parent Guaranty or (c) the validity or enforceability of this
Agreement, the Notes or the Parent Guaranty.

         "Mortgages" shall have the meaning provided in Section 4.14.

         "Mortgaged Rig" shall have the meaning provided in Section 4.14;
provided that such rigs shall constitute Mortgaged Rigs only for so long as the
Mortgage thereon is required to remain in effect pursuant to the terms of this
Agreement.

         "NACL" shall have the meaning provided in Section 6.12(c).

         "NDNBV" shall have the meaning provided in Section 6.11.

         "NDUS" shall have the meaning provided in Section 7.05.

         "NDUS Note" shall have the meaning provided in Section 7.05

         "Note" shall have the meaning provided in Section 1.01.

         "Notice Office" shall mean the office of the Trustee set forth below
its signature hereto, or such other office as the Trustee may designate to the
Company from time to time.

         "Obligations" shall mean (i) all amounts, direct or indirect,
contingent or absolute, of every type or description, and at any time existing,
owing to the Trustee or any Purchaser pursuant to the terms of this Agreement or
any other Credit Document (other than the Parent Guaranty) and (ii) each and
every obligation of the Company or NACL as owners under the Mortgages.

         "Parent Guarantor" means Noble Drilling Corporation, a Delaware
corporation.

         "Parent Guaranty" shall have the meaning provided in Section 4.11(i)

         "Payment Office" shall mean the office of the Trustee set forth below
its signature hereto, or such other office as the Trustee may designate to the
Company from time to time.



                                      -31-
<PAGE>   36


         "Permitted Indebtedness" shall mean Indebtedness permitted by Section
7.03.

         "Permitted Investments" shall mean and include the following:

         (a)  the Company may make Investments in cash and Cash Equivalents;

         (b) the Company may acquire and hold receivables owing to them, if
created or acquired in the ordinary course of business and payable or
dischargeable in accordance with customary trade terms;

         (c) the Company may make loans and advances to employees in the
ordinary course of business or in connection with employee relocation in an
aggregate principal amount not to exceed $500,000 at any time outstanding; and

         (d) the Company may acquire and own investments (including debt
obligations) received in connection with the bankruptcy or reorganization of
suppliers and customers and in settlement of delinquent obligations of, and
other disputes with, customers and suppliers arising in the ordinary course of
business.

         "Permitted Liens" shall mean Liens permitted by Section 7.04.

         "Person" shall mean any individual, partnership, joint venture, firm,
corporation, association, limited liability company, trust or other enterprise
or any government or political subdivision or any agency, department or
instrumentality thereof.

         "Petrobras Contract" shall mean Contract No. 101.2.038.97-5 Charter
Contract -- Contract for the Charter of Floating Unit with Dynamic Positioning
entered into between Petroleo Brasileiro S.A.-Petrobras and NDNBV.

         "Plan" shall mean any multiemployer or single-employer plan as defined
in Section 4001 of ERISA, which is maintained or contributed to by (or to which
there is an obligation to contribute of) the Company or an ERISA Affiliate.

         "Pre-Delivery Mortgaged Rigs" shall have the meaning provided in
Section 6.12(c).

         "Project" shall mean the upgrade of the Vessel from a submersible
drilling rig to a Noble Drilling EVA-4000(tm) semisubmersible drilling rig.

         "Project Completion Date" shall mean the date upon which all work
relating to the Project has been completed in accordance with the Construction
Contract and the Vessel has been delivered by the Shipyard to the Company free
from any Lien or other claim of the Shipyard.

         "Purchaser" shall have the meaning provided in the first paragraph of
this Agreement.

         "RCRA" shall mean the Resource Conservation and Recovery Act, as
amended, 42 U.S.C. ss. 6901 et seq.



                                      -32-
<PAGE>   37


         "Regulation U" shall mean Regulation U of the Board of Governors of the
Federal Reserve System as from time to time in effect and any successor to all
or a portion thereof establishing margin requirements.

         "Replaced Purchaser" shall have the meaning provided in Section 1.06.

         "Replacement Purchaser" shall have the meaning provided in Section
1.06.

         "Required Purchasers" shall mean Purchasers whose outstanding
Commitments (or, if after the Total Commitment has been terminated, outstanding
Notes) constitute greater than 66 2/3% of the sum of the Total Commitment (or,
if after the Total Commitment has been terminated, the total principal balance
of all outstanding Notes, other than those held by the Company or any Affiliate,
at such time).

         "Restricted Payments" shall mean any Dividend or Investment, other than
Permitted Investments.

         "Scheduled Repayment" shall mean a Series A Scheduled Repayment, a
Series B Scheduled Repayment or a Series C Scheduled Repayment.

         "Scheduled Repayment Date" shall mean a Series A Scheduled Repayment
Date, a Series B Scheduled Repayment Date or a Series C Scheduled Repayment
Date.

         "SEC" shall mean the Securities and Exchange Commission or any
successor thereto.

         "Second Intercompany Note" shall mean the Promissory Note, dated May
27, 1998, made by the Company and payable to the order of NDUS in the original
principal amount of $17,003,000.

         "Secured Creditors" shall have the meaning assigned to such term in the
respective Security Documents.

         "Security Documents" shall mean the Mortgages and the Assignments of
Insurances.

         "Series" shall mean the respective series of Notes issued pursuant to
this Agreement, with their being three separate Series, i.e., Series A Notes,
Series B Notes and Series C Notes.

         "Series A Commitment" shall mean, with respect to each Purchaser, the
amount set forth opposite such Purchaser's name in Annex I directly below the
column entitled "Series A Commitment," as the same may be (x) reduced from time
to time pursuant to Section 2.02 and/or 8 or (y) adjusted as a result of
assignments to or from such Purchaser pursuant to Section 11.04.

         "Series A Maturity Date" shall mean December 1, 2001.

         "Series A Note" shall have the meaning provided in Section 1.01.



                                      -33-

<PAGE>   38

         "Series A Rate" shall mean 6.43% per annum.

         "Series A Scheduled Repayment" shall have the meaning provided in
Section 3.02.

         "Series A Scheduled Repayment Date" shall have the meaning provided in
Section 3.02.

         "Series B Commitment" shall mean, with respect to each Purchaser, the
amount set forth opposite such Purchaser's name in Annex I directly below the
column entitled "Series B Commitment," as the same may be (x) reduced from time
to time pursuant to Section 2.02 and/or 8 or (y) adjusted as a result of
assignments to or from such Purchaser pursuant to Section 11.04.

         "Series B Note" shall have the meaning provided in Section 1.01.

         "Series B Rate" shall mean 6.50% per annum.

         "Series B Scheduled Repayment" shall have the meaning provided in
Section 3.02.

         "Series B Scheduled Repayment Date" shall have the meaning provided in
Section 3.02.

         "Series C Commitment" shall mean, with respect to each Purchaser, the
amount set forth opposite such Purchaser's name in Annex I directly below the
column entitled "Series C Commitment," as the same may be (x) reduced from time
to time pursuant to Section 2.02 and/or 8 or (y) adjusted as a result of
assignments to or from such Purchaser pursuant to Section 11.04.

         "Series C Note" shall have the meaning provided in Section 1.01.

         "Series C Rate" shall mean 6.55% per annum.

         "Series C Scheduled Repayment" shall have the meaning provided in
Section 3.02.

         "Series C Scheduled Repayment Date" shall have the meaning provided in
Section 3.02.

         "Shipyard" means the shipyard of TDI Halter, Inc. in Orange, Texas,
where the Project is being undertaken.

         "Subsidiary" of any Person shall mean and include (i) any corporation
more than 50% of whose stock of any class or classes having by the terms thereof
ordinary voting power to elect a majority of the directors of such corporation
(irrespective of whether or not at the time stock of any class or classes of
such corporation shall have or might have voting power by reason of the
happening of any contingency) is at the time owned by such Person directly or
indirectly through one or more Subsidiaries and (ii) any partnership,
association, joint venture, limited liability company or other entity in which
such Person directly or indirectly through one or more Subsidiaries, has more
than a 50% equity interest at the time.


                                      -34-
<PAGE>   39


         "Subsidiary Guarantors" shall mean Noble Asset Company Limited, a
company organized and existing under the law of the Cayman Islands and Noble
Drilling (Nederland) B.V., a corporation organized and existing under the laws
of the Netherlands.

         "Subsidiary Guaranty" shall have the meaning provided in Section 4.11.

         "Taxes" shall have the meaning provided in Section 3.04(a).

         "Third Intercompany Note" shall mean the Promissory Note, dated the
Effective Date, made by the Company and payable to the order of NDUS in the
original principal amount of $11,716,000.

         "Total Commitment" shall mean, at any time, the sum of the Commitments
of each of the Purchasers.

         "Total Series A Commitment" shall mean, at any time, the sum of the
Series A Commitments of the Purchasers.

         "Total Series B Commitment" shall mean, at any time, the sum of the
Series B Commitments of the Purchasers.

         "Total Series C Commitment" shall mean, at any time, the sum of the
Series C Commitments of the Purchasers.

         "Trustee" shall have the meaning provided in the first paragraph of
this Agreement and shall include any successor to the Trustee appointed pursuant
to Section 10.09.

         "UCC" shall mean the Uniform Commercial Code.

         "Vessel" shall mean the offshore drilling rig "Noble Paul Wolff"
registered under the laws and flag of the Republic of Panama (Official No.
27269-HT).

         "Voting Stock" shall mean, with respect to any corporation, the
outstanding stock of all classes (or equivalent interests) which ordinarily, in
the absence of contingencies, entitles holders thereof to vote for the election
of directors (or Persons performing similar functions) of such corporation, even
though the right so to vote has been suspended by the happening of such a
contingency.

         "Written" or "in writing" shall mean any form of written communication
or a communication by means of telex or facsimile transmission.

SECTION 10.  THE TRUSTEE.

         10.01 Appointment. (a) The Purchasers hereby designate Chase Bank of
Texas, National Association as Trustee (for purposes of this Agreement, the term
"Trustee" shall also refer to Chase Bank of Texas, National Association in its
capacity as Trustee pursuant to the Credit Documents) to act as specified herein
and in the other Credit Documents. Each Purchaser hereby irrevocably authorizes,
and each holder of any Note by the acceptance of such Note shall be deemed
irrevocably to authorize, the Trustee to enter into and take such action on its
behalf under the provisions of this Agreement, the 


                                      -35-
<PAGE>   40

other Credit Documents and any other instruments and agreements referred to
herein or therein and to exercise such powers and to perform such duties
hereunder and thereunder as are specifically delegated to or required of the
Trustee by the terms hereof and thereof and such other powers as are reasonably
incidental thereto. The Trustee may perform any of its duties hereunder by or
through its respective officers, directors, agents, employees or Affiliates.

         (b) If an Event of Default shall occur and be continuing, upon the
written request of the Required Purchasers, and upon being secured or
indemnified to its satisfaction pursuant to Section 10.06(c), the Trustee shall
proceed to protect and enforce the rights of the Purchasers under this Agreement
and the Credit Documents by a suit or action at law or in equity, either for the
specific performance of any covenant or agreement contained herein or therein,
or in aid of the execution of any power herein or therein granted, or by any
other appropriate judicial or non-judicial proceedings for the enforcement of
any other legal or equitable remedy.

         (c) The Trustee hereby represents to the Company and each Purchaser
that it is duly authorized to enter into this Agreement and each Credit Document
to which it is a party, has duly executed and delivered each such document and
each constitutes a valid and binding agreement of the Trustee enforceable in
accordance with its terms, except to the extent that the enforceability thereof
may be limited by applicable bankruptcy, insolvency, reorganization, moritorium
or similar laws generally affecting creditors' rights and by equitable
principles (regardless of whether enforcement is sought in equity or at law).

         10.02 Nature of Duties. The Trustee shall not have any duties or
responsibilities except those expressly set forth in this Agreement and the
other Credit Documents. Neither the Trustee nor any of its respective officers,
directors, agents, employees or Affiliates shall be liable for any action taken
or omitted by it or them hereunder or under any other Credit Document or in
connection herewith or therewith, unless caused by its or their gross negligence
or willful misconduct. The duties of the Trustee shall be mechanical and
administrative in nature; the Trustee shall not have by reason of this Agreement
or any other Credit Document a fiduciary relationship in respect of any
Purchaser or the holder of any Note; and nothing in this Agreement or any other
Credit Document, expressed or implied, is intended to or shall be so construed
as to impose upon the Trustee any obligations in respect of this Agreement or
any other Credit Document except as expressly set forth herein or therein.

         10.03 Lack of Reliance on the Trustee. Independently and without
reliance upon the Trustee, each Purchaser and the holder of each Note, to the
extent it deems appropriate, has made and shall continue to make (i) its own
independent investigation of the financial condition and affairs of the Credit
Parties in connection with the purchase of the Notes and the taking or not
taking of any action in connection herewith and (ii) its own appraisal of the
creditworthiness of the Credit Parties and, except as expressly provided in this
Agreement, the Trustee shall not have any duty or responsibility, either
initially or on a continuing basis, to provide any Purchaser or the holder of
any Note with any credit or other information with respect thereto, whether
coming into its possession before the purchase of the Notes or at any time or
times thereafter. The Trustee shall not



                                      -36-
<PAGE>   41

be responsible to any Purchaser or the holder of any Note for any recitals,
statements, information, representations or warranties herein or in any
document, certificate or other writing delivered in connection herewith or for
the execution, effectiveness, genuineness, validity, enforceability, perfection,
collectibility, priority or sufficiency of this Agreement or any other Credit
Document or the financial condition of the Credit Parties or be required to make
any inquiry concerning either the performance or observance of any of the terms,
provisions or conditions of this Agreement or any other Credit Document, or the
financial condition of the Credit Parties or the existence or possible existence
of any Default or Event of Default.

         10.04 Certain Rights of the Trustee. If the Trustee shall request
instructions from the Required Purchasers with respect to any act or action
(including failure to act) in connection with this Agreement or any other Credit
Document, the Trustee shall be entitled to refrain from such act or taking such
action unless and until the Trustee shall have received instructions from the
Required Purchasers; and the Trustee shall not incur liability to any Person by
reason of so refraining. Without limiting the foregoing, neither any Purchaser
nor the holder of any Note shall have any right of action whatsoever against the
Trustee as a result of the Trustee acting or refraining from acting hereunder or
under any other Credit Document in accordance with the instructions of the
Required Purchasers.

         10.05 Reliance. The Trustee shall be entitled to rely, and shall be
fully protected in relying, upon any note, writing, resolution, notice,
statement, certificate, telex, teletype or telecopier message, cablegram,
radiogram, order or other document or telephone message signed, sent or made by
any Person that the Trustee believed to be the proper Person, including, without
limitation, counsel to Credit Parties, and, with respect to all legal matters
pertaining to this Agreement and any other Credit Document and its duties
hereunder and thereunder, upon advice and statements of legal counsel to the
Trustee.

         10.06 Indemnification. (a) The Company shall pay to the Trustee from
time to time such compensation for its services as shall have been agreed to by
the Company and the Trustee. The Company shall reimburse the Trustee upon
request for all reasonable out-of-pocket expenses incurred or made by it,
including costs of enforcement of the Credit Documents, in addition to the
compensation for its services. Such expenses shall include the reasonable
compensation and expenses, disbursements and advances of the Trustee's agents,
counsel, accountants and experts. The Company shall defend and indemnify the
Trustee against any and all loss, liability or expense (including reasonable
attorneys' fees) incurred by the Trustee in connection with the administration
of this trust and the performance of their duties hereunder except for any loss,
liability or expense which is ultimately adjudicated to have been caused by the
gross negligence or willful misconduct of the Trustee. The Trustee shall notify
the Company of any claim for which it may seek indemnity promptly upon obtaining
actual knowledge thereof; provided, however, that any failure so to notify the
Company shall not relieve the Company or any Subsidiary Guarantor of its
indemnity obligations hereunder. The Company shall defend the claim and the
indemnified party shall provide reasonable cooperation at the Company's expense
in the defense. Such indemnified parties may have separate counsel and the
Company and the Subsidiary Guarantors, as applicable shall pay the fees and
expenses of such counsel; provided, however, that the Company shall not be
required to pay such fees 



                                      -37-
<PAGE>   42

and expenses if it assumes such indemnified parties' defense and, in such
indemnified parties' reasonable judgment, there is no conflict of interest
between the Company and the Subsidiary Guarantors, as applicable, and such
parties in connection with such defense. The Company's payment obligations
pursuant to this Section shall survive the satisfaction, expiration or
termination of this Agreement, any rejection or termination of this Agreement
under any bankruptcy law or the resignation or removal of the Trustee.

         (b) The rights, privileges, protections and benefits given to the
Trustee, including, without limitation, its rights to be indemnified, are
extended to, and shall be enforceable by, the Trustee in each of its capacities
hereunder.

         (c) The Trustee shall not be required to expend or risk its own funds
or to otherwise incur any financial liability in the performance of any of its
duties hereunder or under the Credit Documents or in the exercise of its rights,
remedies or powers hereunder or under any of the Credit Documents. The Trustee
shall be under no obligation to exercise any of the rights or powers vested in
it by this Agreement or any other applicable Credit Document at the request or
direction of any of the Purchasers, unless such Purchasers shall have offered to
the Trustee security or indemnity reasonably satisfactory to the Trustee against
the costs, expenses and liabilities which might reasonably by incurred by it in
compliance with such request or direction.

         10.07 The Trustee in Its Individual Capacity. In the event that the
Trustee purchases or otherwise acquires any Notes under this Agreement, the
Trustee shall have the rights and powers specified herein for a "Purchaser" and
may exercise the same rights and powers as though it were not performing the
duties specified herein; and the term "Purchasers," "Required Purchasers,"
"holders of Notes" or any similar terms shall, unless the context clearly
otherwise indicates, include the Trustee in its individual capacity; provided,
that any action taken in respect of funds in the Concentration Account shall be
for the pro rata benefit of all Purchasers. The Trustee may accept deposits
from, lend money to, and generally engage in any kind of banking, trust or other
business with the Credit Parties or any Affiliate thereof as if it were not
performing the duties specified herein, and may accept fees and other
consideration from the Credit Parties for services in connection with this
Agreement and otherwise without having to account for the same to the
Purchasers.

         10.08 Holders. The Trustee may deem and treat the payee of any Note as
the owner thereof for all purposes hereof unless and until a written notice of
the assignment, transfer or endorsement thereof, as the case may be, shall have
been filed with the Trustee. Any request, authority or consent of any Person
who, at the time of making such request or giving such authority or consent, is
the holder of any Note shall be conclusive and binding on any subsequent holder,
transferee, assignee or indorsee, as the case may be, of such Note or of any
Note or Notes issued in exchange therefor.

         10.09 Resignation by the Trustee. (a) The Trustee may resign from the
performance of all its functions and duties hereunder and/or under the other
Credit Documents at any time by giving 15 Business Days' prior written notice to
the Company and the Purchasers. Such resignation shall take effect upon the
appointment of a successor Trustee pursuant to clauses (b) and (c) below or as
otherwise provided below.


                                      -38-

<PAGE>   43


         (b) Upon any such notice of resignation, the Required Purchasers shall
appoint a successor Trustee hereunder or thereunder who shall be a commercial
bank or trust company authorized by law to accept the obligations contemplated
hereby and having a combined capital and surplus of at least $500,000,000 as set
forth in its most recently published annual report of condition and being rated
at lease "A" by a recognized rating agency and reasonably acceptable to the
Company.

         (c) If a successor Trustee shall not have been so appointed within such
15 Business Day period, the Trustee, with the consent of the Company, shall then
appoint a successor Trustee who shall serve as Trustee hereunder or thereunder
until such time, if any, as the Required Purchasers appoint a successor Trustee
as provided above.

         10.10 Concentration Account (a) The Trustee shall establish the
Concentration Account into which NDNBV or its successor and assignee shall
deposit any and all payments made to it under the Petrobras Contract. The
Trustee is hereby instructed to disburse all funds deposited with it and
credited to the Concentration Account prior to 2:00 P.M local time on any
Business Day to NDNBV to such account as NDNBV shall designate in writing to the
Trustee from time to time on the same Business Day. Funds received and deposited
after 2:00 P.M. local time shall be so disbursed prior to 2:00 P.M. of the next
Business Day. Receipt of such funds by NDNBV (or if applicable the Company)
shall constitute a representation and warranty by NDNBV (or if applicable the
Company) to each Purchaser and the Trustee that no Default or Event of Default
has occurred and is continuing. Following an assignment or other transfer of the
Petrobras Contract to the Company, in accordance with the terms of this
Agreement, the Company shall have the same rights and obligations under this
Section 10.10(a) as NDNBV and the rights and obligations of NDNBV under this
Section 10.10(a) shall terminate.

         (b) Following the occurrence of a Default or an Event of Default
neither NDNBV nor the Company shall have any right to receive funds from the
Concentration Account and such funds shall be held by the Trustee as security
and applied by the Trustee to outstanding obligations as Required Purchasers may
direct. The Trustee shall mark its books and records to indicate the following
receipt of notification of the occurrence and continuance of a Default or an
Event of Default and the Concentration Account shall be under the exclusive
dominion and control of the Trustee and neither NDNBV nor the Company shall have
any control whatsoever over funds or items deposited in the Concentration
Account.

         10.11 Insurance. The Trustee is not responsible for effecting,
maintaining or renewing any policies of insurance of the Company or any
Affiliate of the Company or for the sufficiency of any insurance policy
coverage.

         10.12 Knowledge of Default. The Trustee shall not be deemed to have
knowledge of any Default or Event of Default hereunder unless and until a
corporate trust officer of the Trustee who is responsible for the account
established hereby shall have actual knowledge of such Default or Event of
Default or shall have received written notice thereof from the Company or any
Purchaser.




                                      -39-
<PAGE>   44

SECTION 11.  MISCELLANEOUS.

         11.01 Payment of Expenses, etc. The Company agrees to (and to cause
each other Credit Party, in respect of the Credit Document to which it is a
party, to): (i) whether or not the transactions herein contemplated are
consummated, pay all reasonable out-of-pocket costs and expenses of the
Purchasers in connection with the negotiation, preparation, execution and
delivery of the Credit Documents and the documents and instruments referred to
therein and any amendment, waiver or consent (whether or not ultimately
executed) relating thereto (including, without limitation, the reasonable fees
and disbursements of White & Case and Watson, Farley & Williams) and of the
Trustee and, after the occurrence and during the continuance of a Default or an
Event of Default, each of the Purchasers and the Trustee in connection with the
enforcement of the Credit Documents and the documents and instruments referred
to therein (including, without limitation, the actual reasonable fees and
disbursements of external counsel for the Trustee and, the Purchasers), provided
that to the extent it is feasible and a conflict of interest does not exist in
the reasonable discretion of the Trustee, the Purchasers and their counsel, the
Purchasers shall use the same counsel in connection with the foregoing; (ii) pay
and hold each of the Purchasers and the Trustee harmless from and against any
and all present and future stamp and other similar taxes with respect to the
foregoing matters and save each of the Purchasers harmless from and against any
and all liabilities with respect to or resulting from any delay or omission
(other than to the extent attributable to such Purchaser) to pay such taxes; and
(iii) defend and indemnify each Purchaser and the Trustee and their respective
officers, directors, employees, representatives and agents from and hold each of
them harmless against any and all losses, liabilities, claims, damages or
expenses incurred by any of them as a result of, or arising out of, or in any
way related to, or by reason of, (a) any investigation, litigation or other
proceeding (whether or not any Purchaser is a party thereto) related to the
entering into and/or performance of any Credit Document or the use of the
proceeds of any Notes hereunder or the consummation of any transactions
contemplated in any Credit Document, whether initiated by Parent Guarantor, the
Company or any other Person, including, without limitation, the actual
reasonable fees and disbursements of external counsel incurred in connection
with any such investigation, litigation or other proceeding (but excluding any
such losses, liabilities, claims, damages or expenses to the extent incurred by
reason of the gross negligence, willful misconduct, unlawful act or material
breach of the terms of this Agreement of the Person to be indemnified), (b) the
ownership, management, transportation, operation or conduct of the Vessel or the
Mortgaged Rigs, including without limitation any claims of workmen, seamen,
contractors and subcontractors, vendors, customers, and any and all Persons,
whether or not based on negligence or theories of strict liability or (c) the
actual or alleged presence of Hazardous Materials in the air, surface water,
groundwater, surface or subsurface of the Mortgaged Rigs or any facility or
location at any time owned or operated by the Company, the generation, storage,
transportation or disposal of Hazardous Materials at the Mortgaged Rigs or any
facility or location at any time owned or operated by the Company, the
non-compliance of the Mortgaged Rigs or any facility or location at any time
owned or operated by the Company with federal, state and local laws,
regulations, and ordinances (including applicable permits thereunder) applicable
to the Mortgaged Rigs or any such facility or location, or any Environmental
Claim asserted against the Company, the Mortgaged Rigs or any facility or
location at any time owned or operated by the Company, including, in each case,
without limitation, the actual reasonable fees and disbursements of external
counsel and other consultants incurred in connection with any such
investigation, litigation or other proceeding (but excluding any 



                                      -40-
<PAGE>   45

losses, liabilities, claims, damages or expenses to the extent incurred by
reason of the gross negligence, willful misconduct, unlawful act or material
breach of the terms of this Agreement of the Person to be indemnified). To the
extent that the undertaking to indemnify, pay or hold harmless the Trustee or
any Purchaser set forth in the preceding sentence may be unenforceable because
it is violative of any law or public policy, the Company shall make the maximum
contribution to the payment and satisfaction of each of the indemnified
liabilities which is permissible under applicable law.

         11.02 Right of Setoff. In addition to any rights now or hereafter
granted under applicable law or otherwise, and not by way of limitation of any
such rights, if an Event of Default then exists, each Purchaser is hereby
authorized at any time or from time to time, without presentment, demand,
protest or other notice of any kind to the Company or to any other Person, any
such notice being hereby expressly waived, to set off and to appropriate and
apply any and all deposits (general or special) and any other Indebtedness at
any time held or owing by such Purchaser (including without limitation by
branches and agencies of such Purchaser wherever located) to or for the credit
or the account of the Company against and on account of the Obligations and
liabilities of the Company to such Purchaser under this Agreement or under any
of the other Credit Documents, including, without limitation, all interests in
Obligations of the Company purchased by such Purchaser pursuant to Section
11.06(b), and all other claims of any nature or description arising out of or
connected with this Agreement or any other Credit Document, irrespective of
whether or not such Purchaser shall have made any demand hereunder and although
said Obligations, liabilities or claims, or any of them, shall be contingent or
unmatured. Without limiting the foregoing, each Purchaser agrees to use
reasonable efforts to notify the Company of any exercise of such Purchaser's
right of setoff granted hereby.

         11.03 Notices. Except as otherwise expressly provided herein, all
notices and other communications provided for hereunder shall be in writing
(including telex or telecopier communication) and mailed or sent by overnight
delivery services, telexed, telecopied or delivered by hand, if to the Company
or any other Credit Party, at the address specified opposite its signature below
or in the other relevant Credit Documents, as the case may be; if to any
Purchaser, at its address specified for such Purchaser on Annex II if to the
Trustee, at the address specified below its signature below; or, at such other
address as shall be designated by any party in a written notice to the other
parties hereto. All such notices and communications shall be effective when
received and, in the case of notice by telecopier, after confirmation of such
receipt has been given by the recipient, excluding by way of automatic receipt
produced by telecopier.

         11.04 Successors and Assigns - Representations of the Purchasers. (a)
This Agreement shall be binding upon and inure to the benefit of and be
enforceable by the respective successors and assigns of the parties hereto,
provided that the Company may not assign or transfer any of its rights or
obligations hereunder without the prior written consent of the Purchasers.

         (b) Each Purchaser represents as to itself that it is purchasing the
Notes for its own account or for one or more separate accounts maintained by it
or for the account of one or more pension or trust funds and not with a view to
the distribution thereof, 



                                      -41-
<PAGE>   46

provided that the disposition of its or their property shall at all times be
within its or their control. Each Purchaser understands that the Notes have not
been registered under the Securities Act of 1933, as amended, and may be resold
only if registered pursuant to the provisions of said Securities Act or if an
exemption from registration is available, except under circumstances where
neither such registration nor such an exemption is required by law and that the
Company is not required to register the Notes.

         (c) Each Purchaser represents that at least one of the following
statements is an accurate representation as to each source of funds (a "Source")
to be used by such Purchaser to pay the purchase price of the Notes to be
purchased by it hereunder:

                  (i) if such Purchaser is an insurance company, the Source does
         not include assets allocated to any separate account maintained by it
         in which any employee benefit plan (or its related trust) has any
         interest, other than a separate account that is maintained solely in
         connection with your fixed contractual obligations under which the
         amounts payable, or credited, to such plan and to any participant or
         beneficiary of such plan (including any annuitant) are not affected in
         any manner by the investment performance of the separate account; or

                  (ii) the Source is either (i) an insurance company pooled
         separate account, within the meaning of Prohibited Transaction
         Exemption ("PTE") 90-1 (issued January 29, 1990), or (ii) a bank
         collective investment fund, within the meaning of the PTE 91-38 (issued
         July 12, 1991) and, except as you have disclosed to the Company in
         writing pursuant to this paragraph (ii), no employee benefit plan or
         group of plans maintained by the same employer or employee organization
         beneficially owns more than 10% of all assets allocated to such pooled
         separate account or collective investment fund; or

                  (iii) the Source constitutes assets of an "investment fund"
         (within the meaning of Part V of PTE 84-14, the "QPAM Exemption")
         managed by a "qualified professional asset manager" or "QPAM" (within
         the meaning of Part V of the QPAM Exemption), no employee benefit
         plan's assets that are included in such investment fund, when combined
         with the assets of all other employee benefit plans established or
         maintained by the same employer or by an affiliate (within the meaning
         of Section V(c)(1) of the QPAM Exemption) of such employer or by the
         same employee organization and managed by such QPAM, exceed 20% of the
         total client assets managed by such QPAM, the conditions of Part I(c)
         and (g) of the QPAM Exemption are satisfied, and (i) the identity of
         such QPAM and (ii) the names of all employee benefit plans whose assets
         are included in such investment fund have been disclosed to the Company
         in writing pursuant to this clause (iii); or

                  (iv) the Source is an insurance company general account, as
         such term is defined in PTE 95-60 (issued July 12, 1995) and as of the
         date of this Agreement there is no employee benefit plan with respect
         to which the aggregate amount of such general account's reserves and
         liabilities for the contracts held by or on behalf of such employee
         benefit plan and all other employee benefit plans maintained by the
         same employer (and affiliates thereof as defined in Section V(a)(1) of
         PTE 95-60) or by the same employee organization (in each case
         determined in accordance with the provisions of PTE 95-60) exceeds 10%
         of the total reserves and liabilities



                                      -42-
<PAGE>   47

         of such general account (as determined under PTE 95-60) (exclusive of
         separate account liabilities) plus surplus as set forth in the National
         Association of Insurance Commissioners Annual Statement filed with the
         state of domicile of such Purchaser; or

                  (v) the Source is the assets of one or more employee benefit
         plans which are managed by an "in-house asset manager," as that term is
         defined in PTE 96-23 (issued April 10, 1996), the conditions of Part
         (I)(a), (b), (c), (g) and (h) of such exemption have been met with
         respect to the purchase of the Notes and the names of all employee
         benefit plans whose assets are included in the transaction have been
         disclosed to the Company in writing pursuant to this clause (v); or

                  (vi) the Source is a governmental plan; or

                  (vii) the Source is one or more employee benefit plans, or a
         separate account or trust fund comprised of one or more employee
         benefit plans, each of which has been identified to the Company in
         writing pursuant to this clause (vii); or

                  (viii) the Source does not include assets of any employee
         benefit plan, other than a plan exempt from the coverage of ERISA.

         As used in this Section 11.04, the terms "EMPLOYEE BENEFIT PLAN",
"GOVERNMENTAL PLAN", "PARTY IN INTEREST" and "SEPARATE ACCOUNT" shall have the
respective meanings assigned to such terms in Section 3 of ERISA.

         11.05 No Waiver; Remedies Cumulative. No failure or delay on the part
of the Trustee or any Purchaser in exercising any right, power or privilege
hereunder or under any other Credit Document and no course of dealing between
the Company and the Trustee or any Purchaser shall operate as a waiver thereof;
nor shall any single or partial exercise of any right, power or privilege
hereunder or under any other Credit Document preclude any other or further
exercise thereof or the exercise of any other right, power or privilege
hereunder or thereunder. The rights and remedies herein expressly provided are
cumulative and not exclusive of any rights or remedies which the Trustee or any
Purchaser would otherwise have. No notice to or demand on the Company in any
case shall entitle the Company to any other or further notice or demand in
similar or other circumstances or constitute a waiver of the rights of the
Trustee or the Purchasers to any other or further action in any circumstances
without notice or demand.

         11.06 Payments Pro Rata. Home Office Payment. (a) The Trustee agrees
that promptly after its receipt of any funds in respect of any Obligations of
the Company hereunder, it shall distribute such payment to the Purchasers (other
than any Purchaser that has expressly waived its right to receive its pro rata
share thereof) pro rata based upon their respective shares, if any, of the
Obligations with respect to which such payment was received.

         (b) So long as the original Purchaser or its nominee shall be the
holder of any Note, and notwithstanding anything contained herein or in such
Note to the contrary, the Company will pay all sums becoming due on such Note
for principal, Make-Whole 




                                      -43-
<PAGE>   48

Amount, if any, and interest by the method and at the address specified for such
purpose below its name in Annex II, or by such other method or at such other
address as such Purchaser shall have from time to time specified to the Company
in writing for such purpose, without the presentation or surrender of such Note
or the making of any notation thereon, except that upon written request of the
Company made concurrently with or reasonably promptly after payment or
prepayment in full of any Note, any such Purchaser shall surrender such Note for
cancellation, reasonably promptly after any such request, to the Trustee. Prior
to any sale or other disposition of any Note held by a Purchaser or its nominee
such Purchaser will, at its election, either endorse thereon the amount of
principal paid thereon and the last date to which interest has been paid thereon
or surrender such Note to the Trustee in exchange for a new Note or Notes
pursuant to Section 11.16. The Company will afford the benefits of this Section
11.06(b) to any Institutional Investor that is the direct or indirect transferee
of any Note purchased by such Purchasers under this Agreement and that has made
the same agreement relating to such Note such Purchasers have made in this
Section 11.06(b).

         11.07 Computations. All computations of interest hereunder shall be
made on the basis of a 360 day year of twelve 30 day months.

         11.08 Governing Law; Submission to Jurisdiction; Venue; Waiver of Jury
Trial. (a) This Agreement and the other Credit Documents and the rights and
obligations of the parties hereunder and thereunder shall be construed in
accordance with and be governed by the internal law of the state of New York.
Any legal action or proceeding with respect to this Agreement or any other
Credit Document may be brought in the courts of the state of New York or of the
United States for the Southern District of New York, and, by execution and
delivery of this Agreement, the Company hereby irrevocably accepts for itself
and in respect of its property, generally and unconditionally, the non-exclusive
jurisdiction of the aforesaid courts. The Company further irrevocably consents
to the service of process out of any of the aforementioned courts in any such
action or proceeding by the mailing of copies thereof by registered or certified
mail, postage prepaid, to the Company located outside New York City and by hand
delivery to the Company located within New York City, at its address for notices
pursuant to Section 11.03, such service to become effective 7 days after such
mailing. Nothing herein shall affect the right of the Trustee or any Purchaser
to serve process in any other manner permitted by law or to commence legal
proceedings or otherwise proceed against the Company in any other jurisdiction.

         (b) The Company hereby irrevocably waives any objection which it may
now or hereafter have to the laying of venue of any of the aforesaid actions or
proceedings arising out of or in connection with this Agreement or any other
Credit Document brought in the courts referred to in clause (a) above and hereby
further irrevocably waives and agrees not to plead or claim in any such court
that any such action or proceeding brought in any such court has been brought in
an inconvenient forum.

         (c) Each of the parties to this Agreement hereby irrevocably waives all
right to a trial by jury in any action, proceeding or counterclaim arising out
of or relating to this Agreement, the other Credit Documents or the transactions
contemplated hereby or thereby.

                                      -44-
<PAGE>   49


         (d) Any payment on account of an amount that is payable hereunder in
Dollars which is made to or for the account of any Purchaser in the lawful
currency of any other jurisdiction ("Currency"), whether as a result of any
judgment or order or the enforcement thereof or the realization of any security
or the liquidation of the Person obligated to make such payment shall constitute
a discharge of the such Person's obligation under this Agreement and the other
Credit Documents or the Notes only to the extent of the amount of Dollars which
such Purchaser could purchase in the London foreign exchange markets with the
amount of other Currency in accordance with normal banking procedures at the
rate of exchange prevailing on the first day (other than a Saturday or Sunday)
on which banks in London are generally open for business following receipt of
the payment first referred to above. If the amount of Dollars that could be so
purchased is less than the amount of Dollars originally due to such Purchaser,
the Person obligated hereunder to make such payment shall indemnify and save
harmless such Purchaser from and against all loss or damage arising out of or as
a result of such deficiency. This indemnity shall constitute an obligation
separate and independent from the other obligations contained in this Agreement,
the other Credit Documents or the Notes, shall give rise to a separate and
independent cause of action, shall apply irrespective of any indulgence granted
by such Purchaser from time to time and shall continue in full force and effect
notwithstanding any judgment or order for a liquidated sum in respect of an
amount due hereunder or under any judgment or order.

         11.09 Counterparts. This Agreement may be executed in any number of
counterparts and by the different parties hereto on separate counterparts, each
of which when so executed and delivered shall be an original, but all of which
shall together constitute one and the same instrument. A set of counterparts
executed by all the parties hereto shall be lodged with the Company and the
Trustee.

         11.10 Effectiveness. This Agreement shall become effective on the date
(the "Effective Date") on which (i) the Company, the Trustee and each of the
Purchasers shall have signed a copy hereof (whether the same or different
copies) and shall have delivered the same to the Trustee at the Payment Office
of the Trustee or, in the case of the Purchasers, shall have given to the
Trustee telephonic (confirmed in writing), written telex or facsimile
transmission notice (actually received) at such office that the same has been
signed and mailed to it and (ii) the Company shall have fully satisfied each of
the conditions set forth in Section 4.

         11.11 Headings Descriptive. The headings of the several sections and
subsections of this Agreement are inserted for convenience only and shall not in
any way affect the meaning or construction of any provision of this Agreement.

         11.12 Amendment or Waiver. Neither this Agreement nor any other Credit
Document nor any terms hereof or thereof may be changed, waived, discharged or
terminated unless such change, waiver, discharge or termination is in writing
signed by the Company; the Trustee and the Required Purchasers, provided that no
such change, waiver, discharge or termination shall, without the consent of each
Purchaser affected thereby, (i) extend the maturity date of any Series of Notes,
or reduce the rate or extend the time of payment of interest (other than as a
result of waiving the applicability of any post-default increase in interest
rates) or Fees thereon, or reduce the principal amount 



                                      -45-
<PAGE>   50

thereof, (ii) change the timing of payment or the amount of either the principal
or the Make-Whole Amount (iii) amend, modify or waive any provision of this
Section, (iv) reduce the percentage specified in the definition of Required
Purchasers or (v) consent to the assignment or transfer by the Company of any of
its rights and obligations under this Agreement.

         11.13 Survival. All indemnities, representations and warranties set
forth herein including, without limitation, in Section 1.04, 3.04, 10.07 or
11.01 shall survive the execution and delivery of this Agreement and the
purchase and repayment of the Notes.

         11.14 Domicile of Notes. Each Purchaser may transfer and carry its
Notes at, to or for the account of any branch office, subsidiary or Affiliate of
such Purchaser, provided that the Company shall not be responsible for costs
arising under Section 1.04 or 3.04 resulting from any such transfer (other than
a transfer pursuant to Section 1.05(a)) to the extent not otherwise applicable
to such Purchaser prior to such transfer.

         11.15 Confidentiality. For the purposes of this Section 11.15,
"CONFIDENTIAL INFORMATION" means information delivered to a Purchaser by or on
behalf of the Company or any Subsidiary in connection with the transactions
contemplated by or otherwise pursuant to this Agreement that is proprietary in
nature and that was clearly marked or labeled or otherwise adequately identified
when received by a Purchaser as being confidential information of the Company or
such Subsidiary, provided that such term does not include information that (a)
was publicly known or otherwise known to such Purchaser prior to the time of
such disclosure, (b) subsequently becomes publicly known through no act or
omission by such Purchaser or any person acting on its behalf, (c) otherwise
becomes known to such Purchaser other than through disclosure by the Company or
any Subsidiary or (d) constitutes financial statements delivered to such
Purchaser hereunder that are otherwise publicly available. Each Purchaser will
maintain the confidentiality of such Confidential Information in accordance with
procedures adopted by it in good faith to protect confidential information of
third parties delivered to it, provided that such Purchaser may deliver or
disclose Confidential Information to (i) its directors, officers, employees,
agents, attorneys and affiliates (to the extent such disclosure reasonably
relates to the administration of the investment represented by such Purchaser's
Notes), (ii) such Purchaser's financial advisors and other professional advisors
who agree to hold confidential the Confidential Information substantially in
accordance with the terms of this Section 11.15, (iii) any other holder of any
Note, (iv) any Institutional Investor to which a Purchaser sells or offers to
sell such Note or any part thereof or any participation therein (if such Person
has agreed in writing prior to its receipt of such Confidential Information to
be bound by the provisions of this Section 11.15), (v) any Person from which a
Purchaser offers to purchase any security of the Company (if such Person has
agreed in writing prior to its receipt of such Confidential Information to be
bound by the provisions of this Section 11.15), (vi) any federal or state
regulatory authority having jurisdiction over such Purchaser, (vii) the National
Association of Insurance Commissioners or any similar organization, or any
nationally recognized rating agency that requires access to information about
such Purchaser's investment portfolio or (viii) any other Person to which such
delivery or disclosure may be necessary or appropriate (w) to effect compliance
with any law, rule, regulation or order applicable to such Purchaser, (x) in
response to any subpoena or other legal process, (y) in connection 


                                      -46-

<PAGE>   51

with any litigation to which such Purchaser is a party or (z) if an Event of
Default has occurred and is continuing, to the extent such Purchaser may
reasonably determine such delivery and disclosure to be necessary or appropriate
in the enforcement or for the protection of the rights and remedies under its
Notes and this Agreement. Each holder of a Note, by its acceptance of a Note,
will be deemed to have agreed to be bound by and to be entitled to the benefits
of this Section 11.15 as though it were a party to this Agreement. On reasonable
request by the Company in connection with the delivery to any holder of a Note
of information required to be delivered to such holder under this Agreement or
requested by such holder (other than a holder that is a party to this Agreement
or its nominee), such holder will enter into an agreement with the Company
embodying the provisions of this Section 11.15.

         11.16 (a) Registration of Notes, etc. The Company thereby appoints the
Trustee as its agent solely for purposes of this Section 11.16, to maintain a
register for the registration and registration of transfers of Notes. The name
and address of each holder of one or more Notes, each transfer thereof and the
name and address of each transferee of one or more Notes shall be registered in
such register. Prior to due presentment for registration of transfer, the Person
in whose name any Note shall be registered shall be deemed and treated as the
owner and holder thereof for all purposes hereof, and the Company shall not be
affected by any notice or knowledge to the contrary. The Company shall cause the
Trustee to give to any holder of a Note that is an Institutional Investor
promptly upon request therefor, a complete and correct copy of the names and
addresses of all registered holders of Notes.

         (b) Upon surrender of any Note at the office of the Trustee for
registration of transfer or exchange (and in the case of a surrender for
registration of transfer, duly endorsed or accompanied by a written instrument
of transfer duly executed by the registered holder of such Note or his attorney
duly authorized in writing and accompanied by the address for notices of each
transferee of such Note or part thereof), the Company shall execute and deliver,
at the Company's expense (except as provided below), one or more new Notes (as
requested by the holder thereof) in exchange therefor, in an aggregate principal
amount equal to the unpaid principal amount of the surrendered Note. Each such
new Note shall be payable to such Person as such holder may request and shall be
of the same Series and substantially in the form of the Note so surrendered.
Each such new Note shall be dated and bear interest from the date to which
interest shall have been paid on the surrendered Note or dated the date of the
surrendered Note if no interest shall have been paid thereon. The Company may
require payment of a sum sufficient to cover any stamp tax or governmental
charge imposed in respect of any such transfer of Notes. Notes shall not be
transferred in denominations of less than $100,000, provided that if necessary
to enable the registration of transfer by a holder of its entire holding of
Notes, one Note may be in a denomination of less than $100,000. Any transferee,
by its acceptance of a Note registered in its name (or the name of its nominee),
shall be deemed to have made the representations set forth in Section 11.04(b)
and (c); provided, however, that the Trustee shall not be permitted to register
the transfer of any Note without the prior written consent of the Company if a
transferee makes the representation set forth in clauses (ii), (iii), (v) or
(vii) of Section 11.04(c) as to its source of funds to be used by it to pay the
purchase price of such Note and the Company states to the Trustee that it has
reasonably determined (based on an opinion of counsel provided to the Trustee)
that such transfer would result in 



                                      -47-
<PAGE>   52

a prohibited transaction under Section 406(a)(1)(A)-(D) of ERISA or Section
4975(c)(1)(A)-(D) of the Code.

         (c) Upon receipt by the Company of evidence reasonably satisfactory to
it of the ownership of and the loss, theft, destruction or mutilation of any
Note (which evidence shall be, in the case of an Institutional Investor, notice
from such Institutional Investor of such ownership and such loss, theft,
destruction or mutilation), and

                  (i) in the case of loss, theft or destruction, such Person's
         own unsecured agreement of indemnity shall be deemed to be
         satisfactory, or

                  (ii) in the case of mutilation, upon surrender and
         cancellation thereof,

the Company at its own expense shall execute and deliver, in lieu thereof, a new
Note, in the same principal amount and Series dated and bearing interest from
the date to which interest shall have been paid on such lost, stolen, destroyed
or mutilated Note or dated the date of such lost, stolen, destroyed or mutilated
Note if no interest shall have been paid thereon.









                                      -48-
<PAGE>   53



         If you are in agreement with the foregoing, please sign the form of
agreement on the accompanying counterpart of this Agreement and return it to the
Company, whereupon the foregoing shall become a binding agreement between you
and the Company.

Address:                                    NOBLE DRILLING (PAUL WOLFF) LTD.

c/o Maples and Calder
P.O. Box 309, Ugland Houst
South Church Street, George Town            By: /s/ BYRON L. WELLIVER
Grand Cayman, Cayman Islands                    ------------------------------
British West Indies                             Name:  Byron L. Welliver
Attn: John F. Dyke, Esq.                        Title: Senior Vice President -
Telephone: (345) 949-8066                              Finance
Telecopy: (345) 949-8080

with a copy to:

10370 Richmond Avenue, Suite 400
Houston, TX  77042
Attn:    Byron L. Welliver
Telephone:  (713) 974-3131
Facsimile:  (713) 974-3181

The foregoing is hereby agreed 
to as of the date hereof.



SECURITY CONNECTICUT LIFE INSURANCE COMPANY


By: /s/ JAMES V. WITTICH
   ----------------------------------
    Name:  James V. Wittich 
    Title: Assistant Treasurer




                                      -49-
<PAGE>   54




CHASE BANK OF TEXAS,
     NATIONAL ASSOCIATION,
     as Trustee


By: /s/ MAURI J. COWEN
   ---------------------------------  
    Name: Mauri J. Cowen
    Title: Vice-President and Trust Officer

Address:

Chase Bank of Texas, National Association
Global Trust Department
600 Travis, Suite 1150, 11th floor
Houston, TX 77002
Attn:    Ms. Mauri J. Cowen
         Vice President and Trust Officer
Telephone: (713) 216-6686
Telecopy:   (713) 216-5476


Address:                                    Accepted and agreed for purposes
                                                     of Section 10.10 hereof.
Coolsingel 139
3012 AG Rotterdam
The Netherlands
Attention: Frits W. van Riet
Telephone: 011-31-10-240-5500
Facsimile:   011-31-10-240-5600


with a copy to:                             NOBLE DRILLING (NEDERLAND) B.V.

10370 Richmond Avenue, Suite 400
Houston, TX  77042
Attn:    Byron L. Welliver
Telephone:  (713) 974-3131
Facsimile:  (713) 974-3181

                                            By: /s/ F.W. VAN RIET
                                                --------------------------------
                                                Name: F.W. Van Riet
                                                Title: Director


                                      -50-
<PAGE>   55
                                                                         ANNEX I



                                   COMMITMENTS


<TABLE>
<CAPTION>

PURCHASER                      Series A        Series B          Series C 
- - ---------                      Commitment      Commitment        Commitment         
                               ----------      ----------        ----------        
<S>                            <C>             <C>               <C>       
Principal Life                                 $20,000,000       $30,000,000
Insurance Company

Hartford Life and              $13,000,000
Annuity Insurance
Company

Hartford Accident and          $ 7,000,000
Indemnity Company

The Lincoln National           $ 5,000,000
Life Insurance
Company
                               $ 1,500,000

                               $ 7,500,000

Lincoln National               $   500,000
Reinsurance Company 
(Barbados) Ltd.

Lincoln National               $ 1,000,000
Health & Casualty 
Insurance Company

London Life                    $ 1,500,000
International
Reinsurance 
Corporation

Transamerica                   $ 1,500,000
Occidental Life 
Insurance Company

                               $ 1,500,000

Nationwide Life                                $10,000,000
Insurance Company

Nationwide Life and                            $ 5,000,000
Annuity Insurance Co.

The Penn Mutual Life                           $15,000,000
Insurance Company

USAA Life Insurance                                              $15,000,000
Company

ReliaStar Life                                 $ 4,000,000
Insurance Company

Northern Life                                  $ 4,000,000
Insurance Company

Security Connecticut                           $ 2,000,000
Life Insurance
Company

TOTALS:                        $40,000,000     $60,000,000       $45,000,000
</TABLE>




<PAGE>   1
                                                                     EXHIBIT 4.5





                        INDENTURE OF FIRST NAVAL MORTGAGE
                         




                        NOBLE DRILLING (PAUL WOLFF) LTD.



                                    as Owner


                                     - and -



                   CHASE BANK OF TEXAS, NATIONAL ASSOCIATION,
                                   AS TRUSTEE



                                  as Mortgagee




                                NOBLE PAUL WOLFF


                               Dated July 1, 1998




<PAGE>   2




                                      INDEX


<TABLE>
<CAPTION>

<S>                                                                          <C>
1   REPRESENTATIONS AND COVENANTS.............................................2

2   DEFINITIONS AND INTERPRETATION............................................4

3   MORTGAGE..................................................................7

4   PAYMENT COVENANTS.........................................................7
                                                                              
5   PRESERVATION OF SECURITY..................................................8
                                                                              
6   INSURANCE.................................................................9
                                                                              
7   RIG COVENANTS............................................................12
                                                                             
8   PROTECTION OF SECURITY...................................................17
                                                                             
9   ENFORCEABILITY AND MORTGAGEE'S POWERS....................................18
                                                                             
10  APPLICATION OF MONEYS....................................................20
                                                                             
11  FURTHER ASSURANCES.......................................................21
                                                                             
12  POWER OF ATTORNEY........................................................22
                                                                             
13  INDEMNITIES..............................................................22
                                                                             
14  EXPENSES.................................................................23
                                                                             
15  COMMUNICATIONS...........................................................24
                                                                             
16  ASSIGNMENTS..............................................................24
                                                                             
17  TOTAL AMOUNT, ETC........................................................25
                                                                             
18  WAIVER; AMENDMENT........................................................25
                                                                             
19  MISCELLANEOUS............................................................25
                                                                             
20  JURISDICTION.............................................................26
</TABLE>                                                                      

EXHIBIT 1         FORM OF NOTE PURCHASE AGREEMENTS   
                  AND THE FORM OF SERIES
                  A NOTE, SERIES B NOTE AND SERIES C NOTE



<PAGE>   3




         THIS INDENTURE OF FIRST NAVAL MORTGAGE made and entered into this 1st
day of July, 1998, between NOBLE DRILLING (PAUL WOLFF) LTD., duly constituted
and existing in conformity with the laws of the Cayman Islands with its
registered office at Ugland House, South Church Street, George Town, Grand
Cayman, Cayman Islands, British West Indies (hereinafter called the "Owner") and
CHASE BANK OF TEXAS, NATIONAL ASSOCIATION, as Trustee for the Purchasers (as
defined herein) having its office at 600 Travis, Suite 1150, 11th Floor,
Houston, Texas TX 77002, United States of America (hereinafter called the
"Mortgagee"), on the Panamanian rig NOBLE PAUL WOLFF of 13,897 gross registered
tons, 4,169 net registered tons and with a length of 93.68m, a breadth of
100.05m and a depth of 39.62m and Provisional Patente Number 27269-HT
(hereinafter called the "Rig"), duly preliminarily registered under the laws and
flag of the Republic of Panama, the detailed description of which is hereinafter
more particularly set forth.

                              W I T N E S S E T H:

WHEREAS

(A)      The Owner is the sole owner of the whole of the rig NOBLE PAUL WOLFF
         documented under the laws and flag of the Republic of Panama.

(B)      Pursuant to several Note Purchase Agreements each dated as of July 1,
         1998, entered into among (i) the Owner, as issuer (ii) the respective
         purchasers set out in Annex I thereto (collectively, the "Purchasers")
         and (iii) the Mortgagee, as trustee for the Purchasers (in such
         capacity, the "Trustee") (the form of which Note Purchase Agreements
         (without exhibits B through F thereto) is annexed hereto as Exhibit 1),
         the Owner has issued and the Purchasers have purchased certain Fixed
         Rate Senior Secured Notes due December 1, 2001, December 1, 2004 and
         December 1, 2004 (collectively, the "Notes"), divided among Series A
         Notes, Series B Notes and Series C Notes according to the Commitments
         of the Purchasers set forth in Annex I thereto, in an aggregate
         principal amount of $145,000,000. As required by Article 1515 Section 3
         of the Commercial Code of Panama, the dates on which payments of
         principal in respect of the Notes are due may be determined from the
         provisions of the Note Purchase Agreements and the Notes.

(C)      The Owner, in order to secure (i) the full and prompt payment when due
         of (x) the principal of and interest on the Notes issued under the Note
         Purchase Agreements (y) all other obligations and indebtedness
         (including, without limitation, indemnities, Fees and interest thereon)
         of the Owner to the Secured Creditors (as hereinafter defined), whether
         now existing or hereafter incurred under, arising out of or in
         connection with the Note Purchase Agreements and this Mortgage and the
         due performance and compliance with all of the terms, conditions and
         agreements contained in the Note Purchase Agreements and this Mortgage;
         (ii) any and all sums advanced by the Mortgagee in order to preserve
         the Collateral (as hereinafter defined) or preserve its security
         interest in the Collateral; (iii) in the event of any proceeding for
         the collection or enforcement of any indebtedness, obligations, or
         liabilities of the Owner referred to in clause (i) above, after an
         Event of Default shall have occurred and be continuing, the reasonable
         expenses of the Mortgagee of re-taking, holding, preparing for sale or
         lease, selling or otherwise disposing of or realizing on the
         Collateral, or of any exercise by the Mortgagee of its rights
         hereunder,

<PAGE>   4




         together with reasonable attorneys' fees of counsel to the Mortgagee
         and court costs; and (iv) all amounts paid by any Indemnitee as to
         which such Indemnitee has the right to reimbursement under Clause 13 of
         this Mortgage (all such obligations, liabilities, sums and expenses
         referred to in clauses (i) through (iv) above being collectively
         referred to as the "Obligations"). It is acknowledged and agreed that
         the "Obligations" shall include extensions of credit of the types
         described above, whether outstanding on the date of this Mortgage or
         extended from time to time after the date of this Mortgage.

NOW, THEREFORE, the appearing parties, each in the name and on behalf of his
respective principal, state that they hereby execute this Indenture of First
Naval Mortgage pursuant to the following representations:

1        REPRESENTATIONS AND COVENANTS

1.01     The Owner represents and covenants to the Mortgagee that:

         a.       the Owner is the sole and absolute owner of the Rig,
                  preliminarily registered under the laws and the flag of the
                  Republic of Panama;

         b.       the Owner, as sole legal and beneficial owner of the Rig, has
                  received and presently possesses a Provisional Patente of
                  Navigation for the Rig, duly issued by the Republic of Panama
                  under No. 27269-HT;

         c.       neither the whole nor any share in the Rig is subject to any
                  Security Interest (as defined herein) (except for Permitted
                  Liens and the lien of this Mortgage);

         d.       the Owner has not sold or transferred, or agreed to sell or
                  transfer, title to the Rig or any share therein;

         e.       the Owner is a company duly organized and validly existing and
                  in good standing under the laws of the Cayman Islands;

         f.       the Owner has full power and authority (i) to execute and
                  deliver this Mortgage, (ii) to mortgage the Rig as security
                  for the Obligations and (iii) to comply with the provisions
                  of, and perform all its obligations under, this Mortgage;

         g.       the Owner has complied with all statutory and other material
                  requirements relative to the ownership, registration and
                  operation of the Rig;

         h.       the Owner has taken all necessary action to authorize the
                  execution and delivery of this Mortgage and this Mortgage
                  constitutes the legal, valid and binding obligation of the
                  Owner enforceable against the Owner in accordance with its
                  terms (except to the extent limited by applicable bankruptcy,
                  reorganization, insolvency, moratorium or other laws of
                  general application relating to or affecting the enforcement
                  of creditors' rights as from time to time in effect and
                  general equitable principles) and when preliminarily
                  registered with the Public 

                                        2


<PAGE>   5




                  Registry in Panama through the Panamanian Consulate in
                  Houston, Texas will create a legal, valid and enforceable
                  first priority mortgage lien on the Rig subject only to the
                  permanent registration of this Mortgage in the Public Registry
                  in Panama within six months of the date of the preliminary
                  registration;

         i.       the entry into and performance by the Owner of this Mortgage
                  does not and will not during the Security Period (as defined
                  herein) violate in any respect (i) any law or regulation of
                  any governmental or official authority or body, or (ii) any of
                  the constitutive documents of the Owner including the
                  Certificate of Incorporation or the Memorandum of Articles and
                  Association, as amended from time to time, or (iii) any
                  material agreement, contract or other undertaking to which the
                  Owner is a party or which is binding upon the Owner or any of
                  its assets;

         j.       all consents, licenses, approvals and authorizations required
                  in connection with the entry into, performance, validity and
                  enforceability of this Mortgage and the transactions
                  contemplated hereby and thereby have been obtained and are in
                  full force and effect and will be so maintained during the
                  Security Period;

         k.       save for such registrations and filings as are referred to in
                  this Mortgage, it is not necessary for the legality, validity,
                  enforceability or admissibility in evidence of this Mortgage
                  that it or any document relating thereto be registered, filed,
                  recorded or enrolled with any court or authority in any
                  relevant jurisdiction or that any stamp, registration or
                  similar taxes be paid on or in relation to this Mortgage;

         l.       the Owner is in compliance with all applicable Environmental
                  Laws and all Environmental Approvals (as defined herein)
                  relating to the Rig, its operation and management and the
                  business of the Owner (as now conducted and as reasonably
                  anticipated to be conducted in the future) have been obtained
                  and complied with;

         m.       no Environmental Claim has been made or threatened against the
                  Owner or otherwise in connection with the Rig;

         n.       no Environmental Incident (as defined herein) which has
                  resulted, or which could reasonably be expected to result, in
                  an Environmental Claim in excess of US$200,000 has occur-red;
                  and

         o.       the Owner hereby affirms as its representations all of the
                  statements contained in the "WHEREAS" clauses of this
                  Mortgage.

1.02     The representations and warranties of the Owner set out in Clause 1.01
         shall survive the execution of this Mortgage and the purchase of the
         Notes.

2        DEFINITIONS AND INTERPRETATION

2.01     In this Mortgage unless the context otherwise requires, the following
         expressions shall have the following meanings:

                                        3


<PAGE>   6





         "Default Rate" shall mean the rate of interest calculated in accordance
         with Section 1.03(b) of the Note Purchase Agreements;

         "Environmental Approvals" means all approvals, licenses, permits,
         exemptions or authorization required under applicable Environmental
         Laws;

         "Environmental Incident" means (i) any release of Hazardous Materials
         from the Rig, (ii) any incident in which Hazardous Materials are
         released from a vessel other than the Rig and which involves collision
         between the Rig and such other vessel or some other incident of
         navigation or operation, in either case, where the Rig or the Owner are
         actually or allegedly at fault or otherwise liable (in whole or in
         part) or (iii) any incident in which Hazardous Materials are released
         from a vessel other than the Rig and where the Rig is actually or
         potentially liable to be arrested as a result and/or where the Owner is
         actually or allegedly at fault or otherwise liable (and, in each such
         case, "release" shall mean disposing, discharging, injecting, spilling,
         leaking, leaching, dumping, emitting, escaping, emptying, seeping,
         placing and the like, into or upon any land or water or air, or
         otherwise entering into the environment);

         "Indemnitee" shall have the meaning set forth in Section 13.01;

         "Insurances" includes all policies and contracts of insurance (which
         expression includes all entries of the Rig in a protection and
         indemnity association) which are from time to time taken out or entered
         into in respect of the Rig or otherwise by the Owner (whether in the
         sole name of the Owner or in the joint names of the Owner and the
         Mortgagee and all benefits thereof (including claims of whatsoever
         nature and return of premiums);

         "ISM Code" means in relation to its application to the Owner, the Rig
         and its operation:

                  (a) The International Management Code for the Safe Operation
                  of Ships and for Pollution Prevention, currently known or
                  referred to as the 'ISM Code', adopted by the Assembly of the
                  International Maritime Organization by Resolution A.741(18) on
                  4 November 1993 and incorporated on 19 May 1994 into chapter
                  IX of the International Convention for the Safety of Life at
                  Sea 1974 (SOLAS 1974); and

                  (b) all further resolutions, circulars, codes, guidelines,
                  regulations and recommendations which are now or in the future
                  issued by or on behalf of the International Maritime
                  Organization or any other entity with responsibility for
                  implementing the ISM Code, including without limitation, the
                  'Guidelines on implementation or administering of the
                  International Safety Management (ISM) Code by Administrations'
                  produced by the International Maritime Organization pursuant
                  to Resolution A.788(19) adopted on 25 November 1995,

         as the same may be amended, supplemented or replaced from time to time;


                                        4


<PAGE>   7




         "Major Casualty" means any casualty to the Rig in respect whereof the
         claim or the aggregate of the claims against all insurers, before
         adjustment for any relevant franchise or deductible, exceeds Five
         Hundred Thousand United States Dollars (US$500,000) or the equivalent
         in any other currency;

         "Note Purchase Agreements" means, collectively, the several Note
         Purchase Agreements each dated as of July 1, 1998 among the Owner, the
         respective Purchasers and the Mortgagee first referred to in Recital
         (B) hereto, as further amended, restated or supplemented from time to
         time;

         "Obligations" shall have the meaning provided in Recital (C) hereto;

         "Protection and Indemnity Risks" means the usual risks covered by
         protection and indemnity associations of international repute including
         the proportion not recoverable in case of collision under the ordinary
         running-down clause (unless such is recoverable under the relevant hull
         and machinery coverage);

         "Requisition Compensation" means all moneys or other compensation
         payable during the Security Period by reason of requisition for title
         or other compulsory acquisition of the Rig otherwise than by
         requisition for hire;

         "Rig" means the vessel described in Recital (A) hereto and includes any
         share or interest therein and her engines, machinery, boats, tackle,
         outfit, spare gear, fuel, consumable or other stores, belongings and
         appurtenances whether on board or ashore and whether now owned or
         hereafter acquired (but excluding therefrom any leased equipment not
         affixed to the Rig and owned by third parties);

         "Secured Creditors" shall mean the Purchasers and the Mortgagee;
         "Security Interest" means a mortgage, charge (whether fixed or
         floating), pledge, lien, hypothecation, assignment, trust arrangement,
         title retention or other security interest or arrangement of any kind
         whatsoever;

         "Security Period" means the period from the date of the Note Purchase
         Agreements and ending on the date all and any amounts together with
         interest, fees and all other obligations under the Credit Documents are
         indefeasibly paid in full;

         "Total Loss" means (a) the actual, constructive, arranged, agreed, or
         compromised total loss of the Rig; (b) the requisition for title or
         other compulsory acquisition or forfeiture of the Rig otherwise than by
         requisition for hire; (c) the capture, seizure, arrest, detention or
         confiscation of the Rig by any government or by persons acting or
         purporting to act on behalf of any government unless the Rig be
         released from such capture, seizure, arrest or detention within sixty
         (60) days after the occurrence thereof;

         "United States Dollars" and "US$" means the lawful currency of the
         United States of America;


                                        5


<PAGE>   8




         "War Risks" includes the risk of mines and all risks excluded from the
         standard form of American marine policy by the free of capture and
         seizure clause.

2.02     Except where otherwise expressly provided herein or unless the context
         otherwise requires, words and expressions defined in the Note Purchase
         Agreements shall bear the same meanings when used in this Mortgage.

2.03     In this Mortgage:

         (a)      Clause headings are inserted for convenience only and shall
                  not affect the construction of this Mortgage and, unless
                  otherwise specified, all references to Clauses are to clauses
                  of this Mortgage;

         (b)      unless the context otherwise requires, words denoting the
                  singular number shall include the plural and vice versa;

         (c)      references to persons include bodies corporate and
                  unincorporated;

         (d)      references to assets include property, rights and assets of
                  every description;

         (e)      references to any document are to be construed as references
                  to such document as amended or supplemented from time to time;
                  and

         (f)      references to any enactment include re-enactments, amendments
                  and extensions thereof

3        MORTGAGE

3.01     In order to secure the Obligations the Owner has granted and mortgaged
         and hereby does by these presents grant and mortgage unto the
         Mortgagee, its successors and assigns, in accordance with the
         provisions of Chapter V, Title IV of Book Second of the Code of
         Commerce and pertinent provisions of the Civil Code and other
         legislation of the Republic of Panama, the whole of the Rig, the
         detailed description of which is as follows:

                  offshore drilling rig vessel NOBLE PAUL WOLFF; gross tonnage
                  approximately 13,897; net tonnage approximately 4,169; length
                  overall 93.68 meters, breadth 100.05 meters; depth 39.62
                  meters; built in 1981 by Ingalls Shipbuilding in the United
                  States of America; radio call letters HP-9321;


         TO HAVE AND TO HOLD the same unto the Mortgagee, its successors and
         assigns forever, upon the terms herein set forth for the enforcement of
         the Obligations.

         PROVIDED ONLY and the condition of these presents is such that if the
         Owner or its successors and assigns shall pay or cause to be repaid to
         the Secured Creditors and their respective successors or assigns the
         Obligations in their entirety as and when the same


                                        6

<PAGE>   9




         shall become due and payable in accordance with the ten-ns of the Note
         Purchase Agreements, the Notes and this Mortgage and shall observe and
         comply with the covenants, terms and conditions contained in the Note
         Purchase Agreements, the Notes and this Mortgage, expressed or implied
         to be performed, observed or complied with by and on the part of the
         Owner and its successors and assigns, then these presents and the
         rights hereunder shall cease, determine and be void upon the discharge
         of this Mortgage by the Mortgagee and, in such event, the Mortgagee
         agrees to furnish, execute and record, at the expense of the Owner, all
         such documents as the Owner may reasonably require to discharge this
         Mortgage, otherwise to be and remain in full force and effect.

         Notwithstanding anything to the contrary herein it is not intended that
         any provision of this Mortgage shall waive the priority and preferred
         status of this Mortgage and that if any provision or part thereof
         herein shall be construed as waiving the priority and preferred status
         of this Mortgage then such provision shall to such extent be void and
         of no effect.

3.02     The Owner shall remain liable to perform all the obligations assumed by
         it in relation to the Rig and none of the Secured Creditors shall be
         under any obligation of any kind whatsoever in respect thereof or be
         under any liability whatsoever in event of any failure by the Owner to
         perform its obligations in respect thereof.

3.03     This Mortgage, when it shall have been duly executed and signed on
         behalf of the parties, shall be provisionally registered through the
         Panamanian Consulate at Houston, Texas and thereafter within six (6)
         months permanently registered in the Public Registry in Panama.

4        PAYMENT COVENANTS

4.01     The Owner hereby covenants with the Secured Creditors:

         (a)      to pay and indemnify the Secured Creditors for all such
                  expenses, claims, liabilities, losses, costs, duties, fees,
                  charges or other moneys as are stated in the Note Purchase
                  Agreements, the Notes and this Mortgage to be payable by the
                  Owner to or recoverable from the Owner by the Secured
                  Creditors (or in respect of which the Owner agrees in this
                  Mortgage to indemnify any of the Secured Creditors) at the
                  times and in the manner specified in the Note Purchase
                  Agreements, the Notes and this Mortgage;

         (b)      to pay interest on any such expenses, claims, liabilities,
                  losses, costs, duties, fees, charges or other moneys referred
                  to in Clause 4.01 (a) from the date on which the relevant
                  expense, claim, liability, loss, cost, duty, fee, charge or
                  other money is paid by any Secured Creditor (both before and
                  after any relevant judgment) at the Default Rate; and

         (c)      to pay and perform its obligations which may be or become due
                  or owing to any Secured Creditor, as the case may be, under
                  the Note Purchase Agreements, the 

                                        7


<PAGE>   10

                  Notes and this Mortgage at the times and in the manner
                  specified herein or therein.

5        PRESERVATION OF SECURITY

5.01     It is declared and agreed that:

         (a)      the security created by this Mortgage shall be held by the
                  Mortgagee as a continuing security for the performance of the
                  Obligations and that the security so created shall not be
                  satisfied by any intermediate payment or satisfaction of any
                  part of the Obligations;

         (b)      the security so created shall be in addition to and shall not
                  in any way be prejudiced or affected by any of the other
                  Security Documents;

         (c)      the Mortgagee shall not be bound to enforce any of the other
                  Security Documents before enforcing the security created by
                  this Mortgage;

         (d)      no failure or delay on the part of the Mortgagee in exercising
                  any right, power, privilege or remedy hereunder and no course
                  of dealing between Owner and Mortgagee shall operate as a
                  waiver thereof; nor shall any single or partial exercise of
                  any right, power, privilege or remedy hereunder preclude any
                  other or further exercise thereof or the exercise of any other
                  right, power or privilege hereunder. The rights and remedies
                  herein expressly provided are cumulative and not exclusive of
                  any rights or remedies which the Mortgagee would otherwise
                  have. No notice to or demand on the Owner in any case shall
                  entitle the Owner to any other or further notice or demand in
                  similar or other circumstances or constitute a waiver of the
                  rights of the Mortgagee to any other or further action in any
                  circumstances without notice or demand; and

         (e)      any waiver by the Mortgagee of any terms of this Mortgage or
                  any consent given by the Mortgagee under this Mortgage shall
                  only be effective if given in writing and then only for the
                  purpose and upon the terms for which it is given.

5.02     It shall be a condition of any settlement or discharge under this
         Mortgage between the Mortgagee and the Owner that no security or
         payment to the Secured Creditors or any of them by the Credit Parties
         or any other person is avoided or set-aside or ordered to be refunded
         or reduced by virtue of any provision or enactment relating to
         bankruptcy, insolvency, administration or liquidation for the time
         being in force and, if such condition is not satisfied, the Mortgagee
         shall be entitled to recover from the Owner on demand the value of such
         security or the amount of any such payment as if such settlement or
         discharge had not occurred.

5.03     The rights of the Secured Creditors under this Mortgage and the
         security hereby constituted shall not be affected by any act, omission,
         matter or thing which, but for this provision, might operate to impair,
         affect or discharge such rights and security, in whole 




                                        8


<PAGE>   11


         or in part, including without limitation, and whether or not known to
         or discoverable by the Credit Parties, the Secured Creditors or any
         other person:


         (a)      any waiver granted to or composition with the Credit Parties
                  or any other person; or

         (b)      the taking, variation, compromise, renewal or release of or
                  refusal or neglect to perfect or enforce any rights, remedies
                  or securities against any of the Credit Parties or any other
                  persons; or

         (c)      any legal limitation, disability, incapacity or other
                  circumstances relating to the Credit Parties or any other
                  person; or

         (d)      any amendment or supplement to the Note Purchase Agreements,
                  the Notes, any of the other Credit Documents or any other
                  document or security; or

         (e)      the dissolution, liquidation, amalgamation, reconstruction or
                  reorganization of any of the Credit Parties or any other
                  person; or

         (f)      the unenforceability, invalidity or frustration of any
                  obligations of the Credit Party or any other person under the
                  Note Purchase Agreements, the Notes, any of the other Credit
                  Documents or any other document or security.

6        INSURANCE

6.01     The Owner covenants with the Mortgagee throughout the Security Period 
         that:

         (a)      The Owner shall, at its own expense, when and so long as any
                  Obligation remains outstanding, insure the Rig and keep her
                  insured, or cause the Rig to be insured, in lawful money of
                  the United States, in such amounts, for such risks (including
                  without limitation, hull and machinery, Protection and
                  Indemnity Risks, pollution liability, and War Risks), in the
                  broadest forms available in the American, British and
                  Scandinavian insurance markets or in such other major
                  international markets acceptable to the Mortgagee (including
                  without limitation, the form of the loss payable clause and
                  the designation of named assureds), and with such first class
                  insurance companies, underwriters, funds, mutual insurance
                  associations or clubs, as shall be reasonably satisfactory to
                  the Mortgagee. The Owner shall insure the Rig and keep her
                  insured, or cause the Rig to be insured (1) with respect to
                  hull and machinery, including War Risks, for an amount which
                  is not less than her agreed value as set forth in the
                  applicable policies, provided, however, the aggregate amount
                  of such insurances in respect of the Mortgaged Rigs shall
                  never be less than 100% of the aggregate unpaid principal
                  amount of the Notes outstanding from time to time, with a
                  deductible amount not greater than U.S.$1,000,000 per
                  occurrence, except if losses in excess of U.S.$25,000 per
                  occurrence for all vessels and rigs insured by the Parent
                  Guarantor or its Affiliates shall exceed an aggregate amount
                  of U.S.$4,000,000 during any twelve month


                                       9
<PAGE>   12

                  period, thereafter the deductible amount shall be not greater
                  than U.S.$50,000 per occurrence, and (2) with respect to
                  Protection and Indemnity Risks and excess liability coverage
                  for an amount not less than U.S.$400,000,000, with a
                  deductible amount not greater than U.S.$100,000 per
                  occurrence. In addition, the Owner shall, at its own expense,
                  furnish to the Mortgagee a mortgagee's single interest policy
                  providing coverage in respect of the Mortgaged Rigs in an
                  aggregate amount equal to 100% of the aggregate unpaid
                  principal amount of the Notes outstanding from time to time
                  (or in lieu of such mortgagee's interest insurance Owner shall
                  cause the hull and machinery insurances for the Mortgaged Rigs
                  to be endorsed to afford breach of warranty coverage for the
                  benefit of the Mortgagee). Such mortgagee's interest insurance
                  and any additional insurance policies for the benefit of the
                  Mortgagee shall be maintained in the broadest form available
                  in the American, British and Scandinavian markets or other
                  major international markets acceptable to the Mortgagee
                  through underwriters acceptable to the Mortgagee. The Rig
                  shall not operate in or proceed into any area then excluded by
                  trading warranties under its marine or war risk policies
                  (including protection and indemnity) without satisfying the
                  conditions of the relevant policies evidence of which shall be
                  furnished to the Mortgagee.

         (b)      The policy or policies of insurance shall be issued by
                  responsible underwriters reasonably acceptable to the
                  Mortgagee, shall contain conditions, terms, stipulations and
                  insuring covenants satisfactory to the Mortgagee, and shall be
                  kept in full force and effect by the Owner so long as the
                  Credit Documents and the Obligations shall be outstanding. All
                  such policies, binders and other interim insurance contracts
                  shall be executed and issued in the name of the Owner and
                  shall, to the extent required herein, provide that the
                  Mortgagee shall be the loss payee for distribution to the
                  Secured Creditors and the Owner as their interests may appear,
                  and shall provide for at least ten (10) (in case of War Risks,
                  seven (7)) days' prior notice to be given to the Mortgagee by
                  the underwriters or association in the event of cancellation
                  of the policy. The Mortgagee, as Trustee for the Purchasers
                  shall be named as an additional assured on all such policies
                  and insurance contracts, but without liability of the
                  Mortgagee, or the Purchasers for premiums or calls. Upon
                  request of the Mortgagee, the Owner shall cause complete
                  certified copies of all such policies, binders and other
                  interim insurance contracts to be delivered to the Mortgagee.
                  Originals shall also be provided upon the request of the
                  Mortgagee. The Owner shall furnish to the Mortgagee annually a
                  detailed report signed by a firm of marine insurance brokers
                  satisfactory to the Mortgagee as to the insurance maintained
                  in respect of the Rig, as to their opinion as to the adequacy
                  thereof and as to compliance with the provisions of this
                  Clause 6.01.

                  Unless otherwise required by the Mortgagee, by notice to the
                  underwriters (which notice shall be given by the Mortgagee
                  only upon the written request of the Required Purchasers
                  following the occurrence of an Event of Default), although the
                  following insurance is payable to the Mortgagee, (i) any loss
                  under any insurance on the Rig with respect to Protection and
                  Indemnity Risks may be paid 



                                       10


<PAGE>   13


                  directly to the Owner to reimburse it for any loss, damage or
                  expense incurred by it and covered by such insurance or to the
                  person to whom any liability covered by such insurance has
                  been incurred and (ii) in the case of any loss (other than a
                  loss covered by (i) above or by the next following paragraph
                  of this Clause 6.01(b)) under any insurance with respect to
                  the Rig involving any damage to the Rig, the underwriters may
                  pay directly for the repair, salvage or other charges involved
                  or, if the Owner shall have first fully repaired the damage or
                  paid the salvage or other charges, may pay the Owner as
                  reimbursement therefor; provided, however, that if such damage
                  involves a before deductible loss in excess of
                  US$5,000,000.00, the underwriters shall not make such payment
                  without first obtaining the written consent thereto of the
                  Mortgagee (which consent shall not be unreasonably withheld);
                  provided, further, so long as the Mortgagee shall not have
                  received notice from the Owner or any Secured Creditor that an
                  Event of Default has occurred and is continuing, the Mortgagee
                  shall make available to the Owner by an appropriate payment
                  order directed to the interested underwriter the proceeds of
                  any such payment in respect of damage in excess of
                  U.S.$5,000,000 to reimburse the Owner in whole or in part for
                  any expenditures the Owner may have made for repairing the Rig
                  and/or to pay any third party claim, provided the Owner shall
                  have furnished to the Mortgagee a copy of a proof of loss and
                  an adjustment of claim prepared by such underwriter with
                  respect to such expenditures. If the Owner does not effect
                  repairs to the Rig or pay third party claims, the Mortgagee
                  shall be entitled to receive the proceeds of any insurance
                  applicable to such loss and upon payment shall credit the net
                  proceeds of any insurance in accordance with Clause 10.01. Any
                  loss covered by this paragraph which is paid to the Mortgagee
                  but which might have been paid, in accordance with the
                  provisions of this paragraph, directly to the Owner or others,
                  shall be paid by the Mortgagee to, or as directed by, the
                  Owner and all other payments to the Mortgagee of losses
                  covered by this paragraph shall be applied by the Mortgagee in
                  accordance with Clause 10.01.

                  In the event of a Total Loss, all insurance payments therefor
                  shall be paid to the Mortgagee. The Owner shall not declare or
                  agree with the underwriters that the Rig is a Total Loss
                  without the prior written consent of the Mortgagee.

         (c)      In the event of a Total Loss of the Rig, the Mortgagee shall
                  retain out of the insurance payments received on account of
                  such loss any sum or sums that shall be or become owing to the
                  Secured Creditors under the Credit Documents, whether or not
                  the same shall be then due and payable, together with accrued
                  interest and the cost, if any, of collecting the insurance,
                  and pay the balance as provided in Clause 10.

         (d)      The Owner shall comply with and satisfy all of the provisions
                  of each applicable law, regulation, proclamation or order
                  concerning financial responsibility for liabilities imposed on
                  the Owner or the Rig with respect to the carriage of
                  passengers or pollution, and will maintain, or cause to be
                  maintained, all certificates or other evidence of financial
                  responsibility as may be required by





                                       11


<PAGE>   14

                  each such law, regulation, proclamation or order with respect
                  to the trade in which the Rig from time to time is engaged.

         (e)      The Owner shall renew all such insurances as they expire and
                  so as to insure that there is no gap in coverage, keep the
                  Mortgagee advised of the progress of such renewals, and shall
                  provide evidence of such renewal in writing to the Mortgagee
                  as and when each such renewal is effected.

         (f)      The Owner shall punctually pay all premiums, calls,
                  contributions or other sums payable in respect of all such
                  insurances and produce all relevant receipts when so required
                  by the Mortgagee.

         (g)      The Owner shall arrange for the execution of such guarantees
                  as may from time to time be required by any protection and
                  indemnity or war risks association.

         (h)      The Owner shall not employ the Rig or suffer the Rig to be
                  employed otherwise than in conformity with the terms of the
                  instruments of insurance aforesaid relative to the Rig
                  (including any warranties, express or implied, therein)
                  without first obtaining the consent to such employment of the
                  insurers and complying with such requirements as to extra
                  premium or otherwise as the insurers may prescribe.

7        RIG COVENANTS

7.01     The Owner covenants with the Mortgagee that throughout the Security
         Period the Owner will:

         (a)      keep the Rig registered in its name as a Panamanian flag
                  vessel and do or allow to be done nothing whereby such
                  registration may be forfeited or imperilled;

         (b)      not without the previous consent in writing of the Mortgagee
                  change the name of the Rig or make any modification to the Rig
                  which would adversely alter the structure, type or performance
                  characteristics of the Rig or which would materially reduce
                  the value of the Rig;

         (c)      keep the Rig in a good and efficient state of repair
                  consistent with first-class ship- ownership and management
                  practice employed by owners of drilling rigs of similar size
                  and type and so as to maintain her in the highest class
                  available for rigs of its age and type with American Bureau of
                  Shipping, Bureau Veritas, Det norske Veritas, Lloyd's Register
                  of Shipping or another internationally recognized
                  classification society reasonably acceptable to the Mortgagee
                  free of recommendations and qualifications and change of
                  class, save those approved in writing by the Mortgagee and so
                  as to comply with all applicable laws, treaties and
                  conventions of the Republic of Panama and other applicable
                  jurisdictions, and rules and regulations issued thereunder,
                  and have on board as and when required thereby valid
                  certificates showing compliance therewith;


                                       12


<PAGE>   15

         (d)      procure that all repairs to or replacement of any damaged,
                  worn or lost parts or equipment in such manner (both as
                  regards workmanship and quality of materials) as to not
                  materially diminish the value of the Rig and not to remove any
                  material part of, or item of equipment owned by the Owner
                  installed on, the Rig unless (i) the part or item so removed
                  is forthwith replaced by a suitable part or item which is in
                  the same condition as or better condition than the part or
                  item removed, is free from any Security Interest (other than
                  Permitted Liens) in favor of any person other than the
                  Mortgagee and becomes on installation on the Rig the property
                  of the Owner and subject to the security constituted by this
                  Mortgage or (ii) the removal will not materially diminish the
                  value of the Rig;

         (e)      submit the Rig to such periodical or other surveys as may be
                  required for classification purposes and if so required to
                  supply to the Mortgagee copies of all survey reports issued in
                  respect thereof;

         (f)      permit the Mortgagee by independent surveyors to board the Rig
                  at all reasonable times and upon reasonable notice for the
                  purpose of inspecting her condition or for the purpose of
                  satisfying themselves in regard to proposed or executed
                  repairs and to afford all proper facilities for such
                  inspections, provided that unless an Event of Default shall
                  have occurred and be continuing, the cost of any such
                  inspection more frequently than once per calendar year shall
                  be for the account of the Mortgagee;

         (g)      promptly pay and discharge all debts, damages and liabilities
                  whatsoever which have given or may give rise to maritime or
                  possessory liens (other than Permitted Liens) on or claims
                  enforceable against the Rig and all tolls, dues, taxes,
                  assessments, governmental charges, fines and penalties
                  lawfully charged on or in respect of the Rig and all other
                  expenses whatsoever in respect of the Rig and in the event of
                  arrest of the Rig pursuant to legal process, or in the event
                  of her detention in exercise or purported exercise of any such
                  lien or claim as aforesaid, procure the release of the Rig
                  from such arrest or detention forthwith upon receiving notice
                  thereof by providing bail or otherwise as the circumstances
                  may require;

         (h)      not employ the Rig or allow her employment in any trade or
                  business which is unlawful under the laws of any relevant
                  jurisdiction or in carrying illicit or prohibited goods or in
                  any manner whatsoever which can reasonably be expected to
                  render her liable to destruction, seizure or confiscation and
                  in the event of hostilities in any part of the world (whether
                  war be declared or not) not employ the Rig or suffer her
                  employment in carrying any contraband goods or to enter or
                  trade to any zone which is declared a war zone by any
                  government or by the War Risks insurers of the Rig unless
                  there shall have been effected by the Owner (at its expense)
                  such special, additional or modified insurance cover as the
                  Mortgagee may reasonably require;


                                       13


<PAGE>   16

         (i)      promptly furnish to the Mortgagee all such information as it
                  may from time to time require regarding the Rig, her
                  employment, position and engagements, particulars of all
                  towages and salvages and, upon the request of the Mortgagee in
                  writing, copies of all charters and other contracts for her
                  employment or otherwise howsoever concerning her;

         (j)      notify the Mortgagee forthwith by telecopy thereafter
                  confirmed by letter of.

                  (i)      any casualty to the Rig which is or is likely to be a
                           Major Casualty; and

                  (ii)     any occurrence in consequence whereof the Rig has
                           become or could, by the passing of time or otherwise,
                           become a Total Loss; and

                  (iii)    any requirement or recommendation made by any insurer
                           or classification society or by any competent
                           authority which is not complied with in full; and

                  (iv)     any arrest of the Rig or the exercise or purported
                           exercise of any lien on the Rig or any requisition of
                           the Rig for hire; and

                  (v)      any intended dry docking of the Rig, as to which the
                           Owner shall give the Mortgagee 30 days prior notice,
                           provided, that in the event of any emergency dry
                           docking of the Rig, the Owner shall immediately
                           notify the Mortgagee; and

                  (vi)     any intended deactivation or lay-up of the Rig (other
                           than for normal periods of inactivity between
                           contracts for the Rig during which periods the Rig
                           remains manned) and obtain the prior written consent
                           of the Mortgagee;

         (k)      keep proper books of account in respect of the Rig and as and
                  when the Mortgagee may so reasonably require make such books
                  available for inspection on behalf of the Mortgagee and
                  furnish satisfactory evidence that the wages and allotments
                  and the insurance of the master and crew are being regularly
                  paid and that all deductions from crews wages in respect of
                  tax and/or social security liability are being properly
                  accounted for and that the master has no claim for
                  disbursements other than those incurred by him in the ordinary
                  course of trading on the voyage then in progress;

         (l)      comply with the provisions of Section 7 of the Note Purchase
                  Agreements, all of which are expressly incorporated in this
                  Mortgage;

         (m)      not without the previous consent in writing of the Mortgagee
                  (such consent not to be unreasonably withheld), put the Rig
                  into the possession of any person for the purpose of work
                  being done upon her if the aggregate amount at any time due
                  and payable in respect thereof shall or is likely to exceed
                  Five Million United States 



                                       14


<PAGE>   17


                  Dollars (US$5,000,000.00) (or the equivalent in any other
                  currency) unless (i) such person shall first have given to the
                  Mortgagee and in terms satisfactory to it a written
                  undertaking not to exercise any lien on the Rig for the cost
                  of such work or otherwise or (ii) the cost of such work shall
                  be fully covered by applicable insurance;

         (n)      comply with and satisfy all the provisions of applicable laws
                  and regulations of the Republic of Panama, as at any time
                  amended, in order to establish and maintain this Mortgage as a
                  first priority naval mortgage thereunder upon the Rig and upon
                  all renewals, improvements and replacements made in or to the
                  same, and promptly to furnish to the Mortgagee from time to
                  time such proofs as the Mortgagee may request for its
                  satisfaction with respect to the compliance by the Owner with
                  the provisions of this sub-clause, including, appropriate
                  certificates of the Public Registry showing that this Mortgage
                  has been duly registered and filed and is a first and absolute
                  lien on the Rig;

         (o)      place, and use due diligence to retain, a properly certified
                  copy of this Mortgage on board the Rig with her papers and
                  cause such certified copy of this Mortgage to be exhibited to
                  any and all persons having business with the Rig which might
                  give rise to any lien thereon other than a lien for crew's
                  wages and salvage and to any representative of the Mortgagee
                  on demand and to place and keep prominently displayed in the
                  chart room and in the master's cabin of the Rig a framed
                  printed notice in plain type in English of such size that the
                  paragraph of reading matter shall cover a space not less than
                  6 inches wide and 9 inches high reading as follows:

                               "NOTICE OF MORTGAGE

                           This Rig is subject to an Indenture of First Naval
                  Mortgage in favor of CHASE BANK OF TEXAS, NATIONAL
                  ASSOCIATION, as Trustee for the Purchasers defined in said
                  Mortgage, in conformity with the provisions of Chapter V,
                  Title IV of Book Second of the Code of Commerce, and the
                  pertinent provisions of the Civil Code and other legislation
                  of the Republic of Panama. Under the terms of said Mortgage
                  neither the owner, any charterer, the Master of the Rig nor
                  any other person shall have the right, power or authority to
                  create, incur or permit to be placed upon the Rig any other
                  lien whatsoever other than for current crews wages and salvage
                  and Permitted Liens (as that term is defined in said
                  Mortgage)."

         (p)      comply, or procure compliance with, the ISM Code (upon said
                  code becoming legally applicable to the Rig), all
                  Environmental Laws and Environmental Approvals relating to the
                  Rig, its operation or management and the business of the Owner
                  from time to time;

         (q)      notify the Mortgagee forthwith upon:


                                       15


<PAGE>   18



                  (i)      any Environmental Claim which could reasonably be
                           expected to result in damages in excess of
                           US$1,000,000 being or made against the Owner, or
                           otherwise in connection with the Rig; or

                  (ii)     any Environmental Incident occurring, and keep the
                           Mortgagee advised, in writing on such regular basis
                           and in such detail as the Mortgagee shall require, of
                           the Owner's response to such Environmental Claim or
                           Environmental Incident.

         (r)      not sell, mortgage or transfer the Rig (other than as
                  permitted by the Note Purchase Agreements) without the written
                  consent of the Mortgagee having first been obtained, and any
                  such written consent to any one such sale, mortgage or
                  transfer shall not be construed to be a waiver of this
                  provision with respect to any subsequent proposed sale,
                  mortgage or transfer. Any such sale, mortgage or transfer
                  shall be subject to the provisions of this Mortgage and the
                  lien it creates. The Owner shall not (a) charter the Rig to,
                  or permit the Rig to serve under any contract with, a person
                  included within the definition of (i) "national" of a
                  "designated foreign country", or "specially designated
                  national" of a "designated foreign country", in the Foreign
                  Assets Control Regulations or the Cuban Assets Control
                  Regulations of the United States Treasury Department, 31
                  C.F.R. Parts 500 and 515, in each case as amended, (ii)
                  "Government of Libya", "entity of the Government of Libya" or
                  "Libya entity" in the Libyan Sanctions Regulations of the
                  United States Treasury Department, 31 C.F.R. Part 550, as
                  amended, (iii) "Government of Iraq", "entity of the Government
                  of Iraq" or "Iraqi Government entity" in the Iraqi Sanctions
                  Regulations, 31 C.F.R. Part 575, as amended, (iv) "Government
                  of Iran" or "entity owned or controlled by the Government of
                  Iran", in the Iranian Transactions Regulations, 31 C.F.R. Part
                  560, as amended, (v) "Government of Angola or UNITA", "entity
                  of the Government of Angola or UNITA" or "Angola or UNITA
                  entity" in the UNITA (Angola) Sanctions Regulations, 31 C.F.R.
                  Part 590, as amended, (vi) "Government of Sudan" in Executive
                  Order 13067, as amended, and any regulations issued pursuant
                  thereto, or (vii) "Government of the Federal Republic of
                  Yugoslavia (Serbia and Montenegro)", "Government of the
                  Republic of Serbia", or "Government of the Republic of
                  Montenegro" in Executive Order 13088, as amended, and any
                  regulations issued pursuant thereto, all within the meaning of
                  said Regulations or of any regulations, interpretations or
                  rulings issued thereunder or (b) engage in any transaction
                  that violates any provision of said Regulations, or that
                  violates any provision of regulations promulgated from time to
                  time by the Office of Foreign Assets Control, U.S. Department
                  of Treasury, or that violates any Executive Order issued
                  pursuant to the International Emergency Economic Powers Act
                  (50 U.S.C. 1701 et seq.), the National Emergencies Act (50
                  U.S.C. 1601 et seq.), or the Trading With the Enemy Act (50
                  U.S.C. App. 1 et seq.), or (c) call at a Cuban port to load or
                  discharge cargo or to effect repairs on any Rig if such
                  transaction or violation listed in (a) - (c) could (i) expose
                  the Mortgagee to any penalty, sanction or investigation or
                  (ii) jeopardize the lien created by this 



                                       16


<PAGE>   19


                  Mortgage or (iii) have a material adverse effect on the Owner
                  or the operation of the Rig;

         (s)      shall not cause or permit the Rig to be operated in any manner
                  contrary to law (except where the failure to operate in
                  compliance with any law would not have a material adverse
                  effect on the Owner or the Rig, or would not have an adverse
                  effect on the lien of this Mortgage), shall not abandon the
                  Rig in a foreign port and shall not engage in any unlawful
                  trade or violate any law or carry any cargo that shall expose
                  the Rig to forfeiture or capture.

8        PROTECTION OF SECURITY

8.01     The Mortgagee shall without prejudice to its other rights and powers
         under this Mortgage and the other Credit Documents be entitled (but not
         bound) at any time and as often as may be necessary (but unless an
         Event of Default shall have occurred and be continuing with prior
         written notice to the Owner) to take any such action as it may in the
         reasonable exercise of its discretion think fit for the purpose of
         protecting or maintaining the security created by this Mortgage and the
         other Credit Documents (including, without limitation, such action as
         is referred to in Clause 8.02) and each and every expense, liability,
         or loss (including, without limitation, reasonable legal fees) so
         incurred by the Secured Creditors in or about the protection or
         maintenance of the said security together with interest payable thereon
         under Clause 4.01(b) shall be repayable to it by the Owner on demand.

8.02     Without prejudice to the generality of Clause 8.01:

         (a)      if the Owner does not comply with the provisions of Clause 6
                  or any of them the Mortgagee shall be entitled (but not bound)
                  to effect or to replace and renew and thereafter to maintain
                  the Insurances in such manner it, in its discretion, may think
                  fit and to require that all policies, contracts and other
                  records relating to the Insurances (including details of any
                  correspondence concerning outstanding claims) be forthwith
                  delivered to such brokers as the Mortgagee may nominate and,
                  upon the direction of the Mortgagee to collect, recover,
                  compromise and give a good discharge for all claims then
                  outstanding or thereafter arising under the Insurances or any
                  of them and to take over or institute (if necessary using the
                  name of the Owner) all such proceedings in connection
                  therewith as the Mortgagee in its absolute discretion, may
                  think fit and to permit the brokers through whom the
                  collection or recovery is effected to charge the usual
                  brokerage therefor;

         (b)      if the Owner does not comply with the provisions of Clause
                  7.01(d) and/or 7.01(f) or any of them, the Mortgagee shall be
                  entitled (but not bound) to arrange for the carrying out of
                  such repairs to, and/or surveys of the Rig as it deems
                  expedient or necessary; and

         (c)      if the Owner does not comply with the provisions of Clause
                  7.01(g) or any of them, the Mortgagee shall be entitled (but
                  not bound) to pay and discharge all 



                                       17


<PAGE>   20

                  such debts, damages and liabilities and all such tolls, dues,
                  taxes, assessments, charges, fines, penalties and other
                  outgoings as are therein mentioned and/or to take any such
                  measures as it deems expedient or necessary for the purpose of
                  securing the release of the Rig.

9        ENFORCEABILITY AND MORTGAGEE'S POWERS  

9.01     Upon the happening of any of the Events of Default specified in the
         Note Purchase Agreements but without the necessity for any court order
         or declaration in any jurisdiction to the effect that an Event of
         Default has occurred (and whether prior to or after the Mortgagee or
         the Required Purchasers having served on the Owner any such notice as
         is referred to in Section 8 of the Note Purchase Agreements) the
         security constituted by this Mortgage shall become immediately
         enforceable and the Mortgagee shall be entitled, as and when it may
         from time to time see fit, to put into force and exercise all or any of
         the powers possessed by it as mortgagee of the Rig or otherwise and in
         particular:

         (a)      to exercise all the rights and remedies in foreclosure and
                  otherwise given to mortgagees by the laws of the Republic of
                  Panama or other applicable laws;

         (b)      to take possession of the Rig whether actually or
                  constructively and/or otherwise to take control of the Rig
                  wherever the Rig may be and cause the Owner or any other
                  person in possession of the Rig forthwith upon demand to
                  surrender the same to the Mortgagee without legal process and
                  without liability of the Mortgagee for any losses or damages
                  incurred thereby and without having to render accounts to the
                  Owner in connection therewith;

         (c)      to require that all policies, contracts, certificates of entry
                  and other records relating to the Insurances (including
                  details of and correspondence concerning outstanding claims)
                  be forthwith delivered to or to the order of the Mortgagee;

         (d)      to collect, recover, compromise and give a good discharge for
                  or procure that the Mortgagee collect, recover, compromise and
                  give good discharge for any and all moneys or claims for
                  moneys then outstanding or thereafter arising under the
                  Insurances or any Requisition Compensation and to permit any
                  brokers through whom collection or recovery is effected to
                  charge the usual brokerage therefor;

         (e)      to take over or institute (if necessary using the name of the
                  Owner) all such proceedings in connection with the Rig, the
                  Insurances, or any Requisition Compensation as the Mortgagee
                  in its absolute discretion thinks fit and to discharge,
                  compound, release or compromise claims against the Owner in
                  respect of the Rig which have given or may give rise to any
                  charge or lien on the Rig or which are or may be enforceable
                  by proceedings against the Rig;

         (f)      to sell the Rig or any share therein free from any claim of or
                  by the Owner of any nature whatsoever, and with or without the
                  benefit of any charterparty or other contract for her
                  employment, by public auction or private contract at such
                  place 




                                       18


<PAGE>   21

                  and upon such terms (including, without limitation, on terms
                  such that payment of some or all of the purchase price be
                  deferred) as the Mortgagee in its absolute discretion may
                  determine with power to postpone any such sale, without being
                  answerable for any loss occasioned by such sale or resulting
                  from postponement thereof, and/or itself to purchase the Rig
                  at any such public auction and to set off the purchase price
                  against all or any part of the Obligations, subject to notice
                  of sale being given by the Mortgagee to the Owner and other
                  mortgagees of record, if any, by airmail, postage pre-paid and
                  by publication once in a newspaper of general circulation in
                  the City of Panama, Republic of Panama, not less than twenty
                  (20) calendar days in advance of the sale, to satisfy the
                  requirement of notice of sale contained in Article 1527 of the
                  Panama Code of Commerce. Such notice shall be necessary only
                  in respect of the initial date of sale;

         (g)      to manage, insure, maintain and repair the Rig and to charter,
                  employ, sail or lay up the Rig in such manner, upon such terms
                  and for such period as the Mortgagee in its absolute
                  discretion deems expedient and for the purposes aforesaid the
                  Mortgagee shall be entitled to do all acts and things
                  incidental or conducive thereto and in particular to enter
                  into such arrangements respecting the Rig, and the insurance,
                  management, maintenance, repair, classification, chartering
                  and employment of the Rig, in all respects as if the Mortgagee
                  were the owner of the Rig and without being responsible for
                  any loss thereby incurred;

         (h)      to recover from the Owner on demand any expenses, liabilities
                  or losses as may be incurred by the Mortgagee in or about the
                  exercise of the power vested in the Mortgagee under Clause
                  9.01(g); and

         (i)      generally, to recover from the Owner on demand each and every
                  expense, liability or loss incurred by the Mortgagee in or
                  about or incidental to the exercise by it of any of the powers
                  aforesaid.

9.02     The Mortgagee shall not be obliged to make any enquiry as to the nature
         or sufficiency of any payment received by it under this Mortgage or to
         make any claim, take any action or enforce any rights and benefits
         assigned to the Mortgagee by this Mortgage or to which the Mortgagee
         may at any time be entitled hereunder.

9.03     Neither the Secured Creditors nor their agents, managers, officers,
         employees, delegates and advisers shall be liable for any expense,
         claim, liability, loss, cost, damage or expense incurred or arising in
         connection with the exercise or purported exercise of any rights,
         powers and discretions under this Mortgage in the absence of gross
         negligence or willful misconduct.

9.04     The Mortgagee shall not by reason of the taking possession of the Rig
         be liable to account as mortgagee-in-possession or for anything except
         actual receipts or be liable for any loss upon realization or for any
         default or omission for which a mortgagee-in-possession might be
         liable.


                                       19
<PAGE>   22


9.05     Upon any sale of the Rig or any share therein by the Mortgagee the
         purchaser shall not be bound to see or enquire whether the power of
         sale of the Mortgagee has arisen in the manner provided in this
         Mortgage and the sale shall be deemed to be within the power of the
         Mortgagee and the receipt of the Mortgagee for the purchase money shall
         effectively discharge the purchaser who shall not be concerned with the
         manner of application of the proceeds of sale or be in any way
         answerable therefor.

10       APPLICATION OF MONEYS

10.01    (a)      All moneys received by the Mortgagee or any other Secured 
                  Creditor, including, without limitation, in respect of sale of
                  the Rig or any part thereof, in respect of recovery under the
                  Insurances, or in respect of Requisition Compensation, shall
                  be applied in the following manner:

                  (i)      first, to the payment of all amounts owing the
                           Mortgagee or any other Secured Creditors of the type
                           described in clauses (ii), (iii) and (iv) of Recital
                           (C);

                  (ii)     second, to the extent moneys remain after the
                           application pursuant to the preceding clause (i), in
                           retention of an amount equal to any part or parts of
                           the outstanding Obligations as is or are not then due
                           and payable but which will or may become due and
                           payable in the future, and upon same becoming due and
                           payable, in payment to the Purchasers as provided in
                           Clause 10.01(c), with each Purchaser receiving an
                           amount equal to such Obligations held by it or, if
                           the proceeds are insufficient to pay in full all such
                           Obligations, its Pro Rata Share (as defined below) of
                           the amount remaining to be distributed; and

                  (iii)    third, to the extent moneys remain after the
                           application pursuant to the preceding clauses (i) and
                           (ii), and following the termination of this Mortgage
                           pursuant to Clause 3.01, any surplus then remaining
                           shall be paid to the Owner, subject, however, to the
                           rights of the holder of any then existing Lien of
                           which the Mortgagee has actual notice (without
                           investigation).

         (b)      For purposes of this Mortgage "Pro Rata Share" shall mean,
                  when calculating a Purchaser's portion of any distribution or
                  amount in respect of any Obligations, the amount (expressed as
                  a percentage) equal to a fraction the numerator of which is
                  the then unpaid amount of such Obligations owing to or held by
                  such Purchaser and the denominator of which is the then
                  outstanding amount of all such Obligations. For purposes of
                  determining the amount payable to each Purchaser, the
                  Mortgagee shall be entitled to request each Purchaser to
                  furnish it with written notice of the amount of Obligations
                  then owed to it and, to the extent not inconsistent with the
                  Note Purchase Agreements, shall be entitled to rely upon the
                  amounts stated therein in making such distribution.


                                       20


<PAGE>   23

         (c)      All payments required to be made to Purchasers hereunder shall
                  be made to the Mortgagee for the account of the Secured
                  Creditors.

11       FURTHER ASSURANCES

11.01    The Owner shall execute and do all such assurances, acts and things as
         the Mortgagee in its absolute discretion may require for:

         (a)      perfecting or protecting the security created (or intended to
                  be created) by this Mortgage; or

         (b)      preserving or protecting any of the rights of the Mortgagee
                  and the other Secured Creditors under this Mortgage; or

         (c)      ensuring that the security constituted by this Mortgage and
                  the covenants and obligations of the Owner under this Mortgage
                  shall inure to the benefit of any transferee, successor or
                  assignee of the Mortgagee; or

         (d)      enforcing the security constituted by this Mortgage on or at
                  any time after the same shall have become enforceable; or

         (e)      the exercise of any power, authority or discretion vested in
                  the Mortgagee under this Mortgage,

         in any such case, forthwith upon demand by the Mortgagee and at the
         expense of the Owner.

12       POWER OF ATTORNEY

12.01    The Owner, by way of security and in order to more fully secure the
         performance of the Obligations under this Mortgage, hereby irrevocably
         appoints the Mortgagee as its attorney for the duration of the Security
         Period for the purposes of:

         (a)      doing in its name all acts and executing, signing and (if
                  required) registering in its name all documents which the
                  Owner itself could do, execute, sign or register in relation
                  to the Rig (including without limitation, transferring title
                  to the Rig to a third party), provided, however, that such
                  power shall not be exercisable by or on behalf of the
                  Mortgagee until this Mortgage shall have become immediately
                  enforceable pursuant to Clause 9.01 and at all times
                  thereafter; and

         (b)      executing, signing, perfecting, doing and (if required)
                  registering every such further assurance document, act or
                  thing as is referred to in Clause 11.

12.02    The exercise of such power as is referred to in Clause 12.01 (a) by or
         on behalf of the Mortgagee shall not put any person dealing with the
         Mortgagee upon any enquiry as to whether this Mortgage has become
         enforceable nor shall such person be in any way 





                                       21


<PAGE>   24

         affected by notice that this Mortgage has not become enforceable and,
         in relation to both Clauses 12.01(a) and 12.01(b), the exercise by the
         Mortgagee of such power shall be conclusive evidence as against third
         parties of its right to exercise the same.

13       INDEMNITIES

13.01    The Owner will indemnify and save harmless each of the Secured
         Creditors and each agent or attorney appointed by such Secured Creditor
         under or pursuant to this Mortgage (each an "Indemnitee") from and
         against any and all expenses, claims, liabilities, losses, taxes,
         costs, duties, fees and charges suffered, incurred or made by such
         Secured Creditor or such agent or attorney in good faith:

         (a)      in the exercise or purported exercise of any rights, powers or
                  discretions vested in them pursuant to this Mortgage; or

         (b)      in the preservation or enforcement of the rights of the
                  Mortgagee under this Mortgage; or

         (c)      on the release of the Rig from the security created by this
                  Mortgage,

         and the Secured Creditors and each such agent or attorney may retain
         and pay all sums in respect of the same out of money received under the
         powers conferred by this Mortgage. All such amounts recoverable by a
         Secured Creditors or such agent or attorney shall be recoverable on a
         full indemnity basis.

13-02    Without limiting the foregoing Clause 13.01, the Owner hereby further
         indemnities and holds harmless each of the Secured Creditors and their
         respective officers, directors, employees, attorneys and agents from
         and against any and all liabilities, losses, obligations, claims,
         damages, penalties, causes of action, costs and expenses (including,
         without limitation, reasonable attorneys' fees and expenses, consultant
         fees, investigation and laboratory fees) imposed upon or incur-red by
         or asserted against them, or any of them, by reason of (a) an actual,
         alleged or threatened occurrence or incident, including, without
         limitation, any Environmental Incident; (b) any personal injury
         (including wrongful death) or property damage (real or personal) or
         economic damage arising out of or related to occurrence or incident,
         including, without limitation, any Environmental Incident; (c) any
         Environmental Claim brought or threatened, or settlement reached; or
         (d) any violation of laws, orders, regulations, requirements or demands
         of government authorities relating to occurrence or incident,
         including, without limitation, any Hazardous Materials at, or
         discharged from the Rig.

13-03    If, under any applicable law or regulation, and whether pursuant to a
         judgment being made or registered against the Owner or the liquidation
         of the Owner or for any other reason, any payment under or in
         connection with this Mortgage is made or fails to be satisfied in a
         currency (the "payment currency") other than the currency in which such
         payment is due under or in connection with this Mortgage (the
         "contractual currency"), then to the extent that the amount of such
         payment actually received by the Mortgagee, 






                                       22


<PAGE>   25

         when converted into the contractual currency at the rate of exchange,
         falls short ' of the amount due under or in connection with this
         Mortgage, the Owner, as a separate and independent obligation, shall
         indemnify and hold harmless the Mortgagee against the amount of such
         shortfall. For the purposes of this Clause 13.03, "rate of exchange"
         means the rate at which the Mortgagee is able on the date of such
         payment (or, if it is not practicable for the Mortgagee to purchase the
         contractual currency with the payment currency on the date of such
         payment, at the rate of exchange as soon afterwards as is practicable
         for the Mortgagee to do so) to purchase the contractual currency with
         the payment currency and shall take into account any premium and other
         costs of exchange with respect thereto.

14       EXPENSES

14.01    The Owner shall pay to any Secured Creditor or the Mortgagee on demand
         all costs, fees and expenses, including, but not limited to, legal fees
         and expenses and valuation fees and Taxes thereon incurred by any
         Secured Creditor or for which any Secured Creditor may become liable in
         connection with:

         (a)      the negotiation, preparation and execution of this Mortgage;
                  and/or

         (b)      the preserving or enforcing of, or attempting to preserve or
                  enforce, any of its rights under this Mortgage.

14.02    The Owner shall pay to the Mortgagee on demand all costs, fees and
         expenses (including, but not limited to, legal fees and expenses) and
         Taxes thereon incurred by any Secured Creditor in connection with:

         (a)      any variation of, or amendment or supplement to, any of the
                  terms of this Mortgage requested by the Owner, necessary or
                  advisable under applicable law or initiated during the
                  occurrence and continuation of an Event of Default; and/or

         (b)      any consent or waiver required from the Mortgagee in relation
                  to this Mortgage,

         and in each case, regardless of whether the same is actually
         implemented, completed or granted, as the case may be.

14.03    The Owner shall pay promptly all stamp, documentary and other like
         duties and Taxes to which this Mortgage may be subject or give rise and
         shall indemnify the Mortgagee on demand against any and all liabilities
         with respect to or resulting from any delay or omission on the part of
         the Owner to pay any such duties or Taxes.

15       COMMUNICATIONS

15.01    All notices required to be given to the Mortgagee shall be made to the
         following address:


                                       23


<PAGE>   26

                              Chase Bank of Texas, National Association
                              Global Trust Department
                              600 Travis
                              Suite 1150, 11th Floor
                              Houston, Texas 77002
                              Attention:   Ms. Mauri J. Cowen
                                           Vice President and Trust Officer
                              Telephone:   (713) 216-6686
                              Facsimile:   (713) 216-5476



         All other notices shall be made to the addresses provided for in
         Section 1 1.03 of the Note Purchase Agreements.

16       ASSIGNMENTS

16.01    This Mortgage shall be binding upon and shall inure to the benefit of
         the Secured Creditors and their respective transferees, successors and
         permitted assigns, and references in this Mortgage to any of them shall
         be construed accordingly.

16.02    The Owner may not assign or transfer all or any part of its rights
         and/or obligations under this Mortgage.

16.03    Pursuant to Section 11.04 of the Note Purchase Agreements, each
         Purchaser has the right to assign or transfer all or any part of its
         rights and/or obligations under its Note Purchase Agreement on the
         terms therein provided. The Mortgagee shall notify the Owner promptly
         following any such assignment, transfer or change.

17       TOTAL AMOUNT, ETC.

17.01    The total amount of this Mortgage is One Hundred and Forty-Five Million
         United States Dollars (US$145,000,000) of principal plus interest,
         fees, commissions and performance of mortgage covenants. The discharge
         amount is the same as the total amount.

18       WAIVER; AMENDMENT

18.01    None of the terms and conditions of this Mortgage may be changed,
         waived, modified or varied in any manner whatsoever unless in writing
         duly signed by the Owner and the Mortgagee (with the consent of the
         Required Purchasers).

19       MISCELLANEOUS

19.01    This Mortgage shall be governed by the laws of the Republic of Panama.

19.02    If at any time any one or more of the provisions in this Mortgage is or
         becomes invalid, illegal or unenforceable in any respect under any law
         or regulation, the validity, legality and enforceability of the
         remaining provisions of this Mortgage shall not be in any way affected
         or impaired thereby.



                                       24


<PAGE>   27

19.03    The Mortgagee, at any time and from time to time, may delegate by power
         of attorney or in any other manner to any person or persons all or any
         of the powers, authorities and discretions which are for the time being
         exercisable by the Mortgagee under this Mortgage in relation to the
         Rig. Any such delegation may be made upon such terms and subject to
         such regulations as the Mortgagee may think fit. The Mortgagee shall
         not be in any way liable or responsible to the Owner or any Secured
         Creditor for any loss or damage arising from any act, default, omission
         or misconduct on the part of any such delegate.

19.04    The appearing parties hereby confer a special power of attorney on Roy
         Phillipps P., lawyer of Panama, Republic of Panama authorizing him to
         take all necessary steps to record this Indenture of First Naval
         Mortgage in the appropriate registries of the City of Panama, and to
         substitute this Power of Attorney herein granted.

19.05    A certification or determination by the Mortgagee as to any matter
         provided for in this Mortgage shall, in the absence of manifest error,
         be conclusive and binding on the Owner.

19.06    The Mortgagee declares that it accepts the naval mortgage hereby
         created under the terms above set forth.

20       JURISDICTION

20.01    The Owner agrees that the Mortgagee shall have the liberty but shall
         not be obliged to take any proceedings in the courts of any country to
         protect or enforce the security constituted by this Mortgage or to
         enforce any provisions of this Mortgage or to enforce the Obligations
         and for the purpose of any proceedings for such enforcement the Owner
         hereby submits to the jurisdiction of the courts of any country of the
         choice of the Mortgagee.

20.02    Without prejudice to the generality of Clause 20.01, the Mortgagee
         shall have the right to arrest and take action against the Rig at
         whatever place the Rig shall be found lying and for the purpose of any
         action which the Mortgagee may bring before the courts of such
         jurisdiction or other judicial authority and for the purpose of any
         action which the Mortgagee may bring against the Rig, any writ, notice,
         judgment or other legal process or documents may (without prejudice to
         any other method of service under applicable law) be served upon the
         master of the Rig (or upon anyone acting as the master) and such
         service shall be deemed good service on the Owner for all purposes.

20.03    The Owner agrees that should the Mortgagee bring a legal action or
         proceedings against it or its assets in relation to any matters arising
         out of or in connection with this Mortgage, no immunity from such legal
         action or proceedings (which shall be deemed to include, without
         limitation, suit, attachment prior to judgment, other attachment, the
         obtaining of judgment, execution or other enforcement) shall be claimed
         by or on behalf of the Owner or with respect of its assets, and the
         Owner hereby irrevocably waives any such right of immunity which it or
         its assets now has or may hereafter acquire and the Owner hereby
         consents generally in respect of any legal action or proceedings
         arising out of or in 

                                       25


<PAGE>   28


         connection with this Mortgage to the giving out of any relief or the
         issue of any process in connection with such action or proceedings
         including, without limitation, the making, enforcement or execution or
         attachment against any property whatsoever of any order or judgment
         which may be made or given in such action or proceedings.

IN WITNESS whereof the Owner and the Mortgagee have duly executed these presents
the day and year first before written.

NOBLE DRILLING (PAUL WOLFF) LTD.


By: /S/ BYRON L. WELLIVER
    ------------------------------------ 
Name:  Byron L. Welliver
Title: Senior Vice President - Finance

CHASE BANK OF TEXAS, NATIONAL ASSOCIATION, as Trustee


By: /S/ MAURI J. COWEN
    ------------------------------------ 
Name:  Mauri J. Cowen
Title: Vice President and Trust Officer








                                       26

<PAGE>   1
                                                                     EXHIBIT 4.6


                                 PARENT GUARANTY


         GUARANTY, dated as July 1, 1998, by NOBLE DRILLING CORPORATION ("Parent
Guarantor"), a Delaware corporation, in favor of CHASE BANK OF TEXAS, National
Association, as trustee ("Trustee") for the benefit of the Purchasers. All
capitalized terms used herein and not otherwise defined shall have the meanings
provided such terms in the Agreement referred to below.


                              W I T N E S S E T H:


         WHEREAS, Noble Drilling (Paul Wolff) Ltd. (the "Company") has entered
into a Note Purchase Agreement (the "Agreement"), dated the date hereof, among
the Company, the Trustee and the Purchasers, pursuant to which the Company is to
issue and sell, and the Purchasers are to purchase, the Notes referred to
therein;

         WHEREAS, Parent Guarantor will obtain benefits from the purchase of the
Notes by the Purchasers, and it is a condition precedent to the purchase of the
Notes by the Purchasers that Parent Guarantor execute and deliver this Guaranty
guaranteeing the Obligations of the Company under the Agreement and the Notes;

         WHEREAS, Parent Guarantor may reasonably be expected to benefit, either
directly or indirectly, from this Guaranty,,

         NOW, THEREFORE, in consideration of the mutual covenants and agreements
set forth herein and for good and valuable consideration, the receipt and
sufficiency of which is hereby acknowledged, Parent Guarantor hereby agrees as
follows:

         1. The Guaranty. In order to induce the Purchasers to enter into the
Agreement and to purchase the Notes, and in recognition of the direct benefits
to be received by Parent Guarantor from the proceeds of the Notes, Parent
Guarantor hereby unconditionally and irrevocably guarantees, as primary obligor
and not merely as surety the full and prompt payment when due, whether upon
maturity, acceleration or otherwise, of any and all of the (x) Obligations and
(y) all other obligations (including which but for the automatic stay under
Section 362(a) of the Bankruptcy Code, would become due) and liabilities owing
by the Company to the Purchasers under the Agreement (including, without
limitation, indemnities and interest thereon) now existing or hereafter incurred
under arising out of or in connection with the Agreement or any other Credit
Document and the due performance and compliance with the terms of the Credit



<PAGE>   2


Documents by the Company or NACL (collectively, the "Guaranteed Obligations"),
and additionally Parent Guarantor hereby unconditionally and irrevocably
guarantees the performance of all obligations and covenants of Noble Drilling
(Nederland) B.V. ("NDNBV"), or an Affiliate thereof, in its capacity as
contractor under that certain Contract No. 101.2.038.97-5 Charter Contract --
Contract for the Charter of Floating Unit with Dynamic Positioning entered into
between Petroleo Brasileiro S.A.-Petrobras, and NDNBV. If any of the Guaranteed
Obligations becomes due and payable hereunder, Parent Guarantor unconditionally
promises to pay such indebtedness to Secured Creditors, or order, on demand,
together with (without duplication) any and all expenses which may be incurred
by Secured Creditors in collecting any of the Guaranteed Obligations. This
Guaranty is a continuing one and all liabilities to which it applies or may
apply under the terms hereof shall be conclusively presumed to have been created
in reliance hereon. If a claim is ever made upon any Secured Creditor for
repayment or recovery of any amount or amounts received in payment or on account
of any of the Guaranteed Obligations and any of the aforesaid payees repays all
or part of said amount by reason of (i) any judgment, decree or order of any
court or administrative body having jurisdiction over such payee or any of its
property, including, but not limited to any repayment by reason of a
preferential payment or fraudulent transfer or (ii) any settlement or compromise
of any such claim effected by such payee with any such claimant (including the
Company), then and in such event Parent Guarantor agrees that any such judgment,
decree, order, settlement or compromise shall be binding upon Parent Guarantor,
notwithstanding any revocation of this Guaranty or any other instrument
evidencing any liability of the Company, and Parent Guarantor shall be and
remain liable to the aforesaid payees hereunder for the amount so repaid or
recovered to the same extent as if such amount had never originally been
received by any such payee.

         2. Bankruptcy. Additionally, Parent Guarantor unconditionally and
irrevocably guarantees the payment of any and all of the Guaranteed Obligations
to the Secured Creditors whether or not due or payable by the Company upon the
occurrence in respect of the Company of any of the events specified in Section
8.05 of the Agreement, and unconditionally promises to pay such indebtedness on
demand, in Dollars.

         3. Nature of Liability. The liability of Parent Guarantor hereunder is
exclusive and independent of any security for or other guaranty of the
Guaranteed Obligations whether executed by Parent Guarantor, any other guarantor
or by any other party, and the liability of Parent Guarantor hereunder is not
affected or impaired by (a) any direction as to application of payment by the
Company or by any other party or (b) any other continuing or other guaranty,
undertaking or maximum liability of a guarantor or of any other party as to the
Guaranteed Obligations or (c) any payment on or in reduction of any such other
guaranty or undertaking or (d) any dissolution, termination or increase,
decrease or change in personnel by the Company.

         4. Absolute and Independent Obligation. No invalidity, irregularity or
unenforceability of all or any part of the Guaranteed Obligations or of any
security therefor shall affect, impair or be a defence to this Guaranty and this
Guaranty shall be primary, absolute and unconditional notwithstanding the
occurrence of any event or the existence of any other 


                                       2
<PAGE>   3


circumstances which might constitute a legal or equitable discharge of a surety
or guarantor except irrevocable payment in full of the Guaranteed Obligations.
The obligations of Parent Guarantor hereunder are independent of the obligations
of the Company, any other guarantor or any other Person and a separate action or
actions may be brought and prosecuted against Parent Guarantor whether or not
action is brought against the Company or any such other guarantor or Person and
whether or not the Company, or any such other guarantor or other Person be
joined in any such action or actions. Parent Guarantor waives, to the full
extent permitted by law, the benefit of any statute of limitations affecting its
liability hereunder or the enforcement hereof.

         5. Authorization. Parent Guarantor authorizes the Secured Creditors
without notice or demand (except as shall be required by applicable statute and
cannot be waived), and without affecting or impairing its liability hereunder,
from time to time to:

         (a) change the manner, place or terms of payment of, and/or change or
         extend the time of payment of, renew, increase, accelerate or alter,
         any of the Guaranteed Obligations (including any increase or decrease
         in the rate of interest thereon), any security therefor, or any
         liability incurred directly or indirectly in respect thereof, and the
         Guaranty herein made shall apply to the Guaranteed Obligations as so
         changed, extended, renewed or altered;

         (b) take and hold security for the payment of the Guaranteed
         Obligations and sell, exchange, release, surrender, realize upon or
         otherwise deal with in any manner and in any order any property by
         whomsoever at any time pledged or mortgaged to secure, or howsoever
         securing, the Guaranteed Obligations or any liabilities (including any
         of those hereunder) incurred directly or indirectly in respect thereof
         or hereof, and/or any offset thereagainst;

         (c) exercise or refrain from exercising any rights against any Credit
         Party or others or otherwise act or refrain from acting;

         (d) release or substitute any cine or more endorsers, guarantors, the
         Company or other obligors;

         (e) settle or compromise any of the Guaranteed Obligations, any
         security therefor or any liability (including any of those hereunder)
         incurred directly or indirectly in respect thereof or hereof, and may
         substitute the payment of all or any part thereof to the payment of any
         liability (whether due or not) of the Company to its creditors other
         than the Secured Creditors;

         (f) apply any sums by whomsoever paid or howsoever realized to any
         liability or liabilities of the Company to the Secured Creditors
         regardless of what liability or liabilities of the Company remain
         unpaid;


                                       3
<PAGE>   4


         (g) consent to or waive any breach of, or any act, omission or default
         under, this Agreement, any other Credit Document or any of the
         instruments or agreements referred to herein or therein, or otherwise
         amend, modify or supplement this Agreement, any other Credit Document
         or any of such other instruments or agreements; and/or

         (h) take any other action which would, under otherwise applicable
         principles of common law, give rise to a legal or equitable discharge
         of Parent Guarantor from its liabilities under this Guaranty.

         6. Reliance. It is not necessary for the Secured Creditors to inquire
into the capacity or powers of the Company or the officers, directors, partners
or agents acting or purporting to act on their behalf, and any Guaranteed
Obligations made or created in reliance upon the professed exercise of such
powers shall be guaranteed hereunder.

         7. Subordination. Any of the indebtedness of the Company now or
hereafter owing to Parent Guarantor is hereby subordinated to the Guaranteed
Obligations. Prior to the transfer by Parent Guarantor of any note or negotiable
instrument evidencing any of the indebtedness of the Company to Parent
Guarantor, Parent Guarantor shall mark such note or negotiable instrument with a
legend that the same is subject to this subordination. Without limiting the
generality of the foregoing, Parent Guarantor hereby agrees with the Secured
Creditors that it will not exercise any right of subrogation which it may at any
time otherwise have as a result of this Guaranty (whether contractual, under law
or otherwise) until all Guaranteed Obligations have been irrevocably paid in
full in cash.

         8. Waiver. (a) Parent Guarantor waives any right (except as cannot be
waived under law) to require any Secured Creditor (i) proceed against the
Company, any other guarantor or any other party, (ii) proceed against or exhaust
any security held from the Company, any other guarantor or any other party or
(iii) pursue any other remedy in any Secured Creditor's power whatsoever. Parent
Guarantor waives any defense based on or arising out of any defense of the
Company, any other guarantor or any other party, other than irrevocable payment
in full of the Guaranteed Obligations, based on or arising out of the disability
of the Company, any other guarantor or any other party, or the unenforceability
of the Guaranteed Obligations or any part thereof from any cause, or the
cessation from any cause of the liability of the Company other than irrevocable
payment in full of the Guaranteed Obligations. The Secured Creditors may, at
their election, foreclose on any security held by the Collateral Trustee or any
other Secured Creditor by one or more judicial or nonjudicial sales, whether or
not every aspect of any such sale is commercially reasonable (to the extent such
sale is permitted by applicable law), or exercise any other right or remedy the
Secured Creditors may have against the Company or any other party, or any
security, without affecting or impairing in any way the liability of Parent
Guarantor hereunder except to the extent the Guaranteed Obligations have been
irrevocably paid.

         (b) Parent Guarantor waives all presentments, demands for performance,
protests and notices (except notices expressly provided for in the Credit
Documents to be provided to Parent 


                                       4
<PAGE>   5


Guarantor), including,, without limitation, notices of nonperformance, notices
of protest, notices of dishonor, notices of acceptance of this Guaranty, and
notices of the existence, creation or incurring of new or additional Guaranteed
Obligations. Parent Guarantor assumes all responsibility for being and keeping
itself informed of the Company's financial condition and assets, and of all
other circumstances, beating upon the risk of nonpayment of the Guaranteed
Obligations and the nature, scope and extent of the risks which Parent Guarantor
assumes and incurs hereunder, and agrees that the Secured Creditors shall have
no duty to advise Parent Guarantor of information known to them regarding such
circumstances or risks.

         (c) Until such time as the Guaranteed Obligations have been irrevocably
paid in full in cash, Parent Guarantor hereby waives all rights of subrogation
which it may at any time otherwise have as a result of this Guaranty (whether
contractual, under law, or otherwise) to the claims of the Secured Creditors
against the Company or any other guarantor of the Guaranteed Obligations and all
contractual, statutory or common law rights of reimbursement, contribution or
indemnity from the Company or any other guarantor which it may at any time
otherwise have as a result of this Guaranty.

         9. Enforcement. The Secured Creditors agree that this Guaranty may be
enforced only by the action of the Trustee, in each case acting upon the
instructions of the Required Purchasers and no Secured Creditor shall have any
right individually to seek to enforce or to enforce this Guaranty or to realize
upon the security to be granted by the Security Documents, it being understood
and agreed that such rights and remedies may be exercised by the Trustee for the
benefit of the Secured Creditors upon the terms of this Guaranty and the
Security Documents.

         10. Representations, Warranties and Agreements. In order to induce the
Purchasers to accept this Guaranty and to purchase the Notes, Parent Guarantor
makes the following representations and warranties to, and agreements with, the
Purchasers, all of which shall survive the execution and delivery of this
Guaranty:

         (a) Corporate Status. Parent Guarantor is a duly organized and validly
         existing corporation in good standing under the laws of the
         jurisdiction of its organization and has the corporate power and
         authority to own its property and assets and to transact the business
         in which it is engaged.

         (b) Corporate Power and Authority. Parent Guarantor has the corporate
         power and authority to execute, deliver and carry out the terms and
         provisions hereof and has taken all necessary corporate action to
         authorize the execution, delivery and performance hereof Parent
         Guarantor has duly executed and delivered this Guaranty and such
         Guaranty constitutes the legal, valid and binding obligation of Parent
         Guarantor enforceable against Parent Guarantor in accordance with its
         terms, except to the extent that the enforceability thereof may be
         limited by applicable bankruptcy, insolvency, reorganization,
         moratorium or similar laws generally affecting creditors' rights and by
         equitable principles (regardless of whether enforcement is sought in
         equity or at law). 


                                       5
<PAGE>   6

         (c) No Violation. Neither the execution, delivery and performance by
         Parent Guarantor of this Guaranty nor compliance with the terms and
         provisions hereof, nor the consummation of the transactions
         contemplated herein (i) will contravene any applicable provision of
         any law, statute, rule, regulation, order, writ, injunction or decree
         of any court or governmental instrumentality, (ii) will result in any
         breach of any of the terms, covenants, conditions or provisions of, or
         constitute a default under, or result in the creation or imposition of
         (or the obligation to create or impose) any Lien upon any of the
         property or assets of Parent Guarantor pursuant to the terms of, any
         indenture, mortgage, deed of trust, agreement or other instrument to
         which Parent Guarantor or any of its Subsidiaries is a party or by
         which they or any of their respective property or assets are bound or
         to which they are subject, or (iii) will violate any provision of the
         Certificate of Incorporation or Bylaws of Parent Guarantor.

         (d) Litigation. There are no actions, suits or proceedings pending or,
         to the knowledge of Parent Guarantor, after due inquiry, threatened
         with respect to Parent Guarantor or its Subsidiaries that are
         reasonably likely to have a material adverse effect on the rights or
         remedies of the Purchasers or on the ability of Parent Guarantor to
         perform its obligations to them hereunder.

         (e) Governmental Approvals. Except for the orders, consents, approvals,
         licenses, authorizations, validations, recordings, registrations and
         exemptions that have already been duly made or obtained and remain in
         full force and effect, no order, consent, approval, license,
         authorization, or validation of, or filing, recording or registration
         with, or exemption by, any foreign or domestic governmental or public
         body or authority, or any subdivision thereof, is required to authorize
         or is required in connection with (i) the execution, delivery and
         performance hereof, or (ii) the legality, validity, binding effect or
         enforceability hereof

         (f) Investment Company Act. Neither the Parent Guarantor nor any other
         Credit Party is an "investment company" or a company "controlled" by an
         "investment company," within the meaning of the Investment Company Act
         of 1940, as amended.

         (g) Public Utility Holding Company Act. Neither the Parent Guarantor
         nor any other Credit Party is a "holding company," or a "subsidiary
         company" of a "holding company," or an "affiliate" of a "holding
         company" or of a "subsidiary company" of a "holding company," within
         the meaning of the Public Utility Holding Company Act of 1935, as
         amended.

         (h) True and Complete Disclosure. All information (taken as a whole)
         heretofore or contemporaneously furnished by or on behalf of Parent
         Guarantor in writing to the Trustee or any Purchaser for purposes of or
         in connection with the Agreement, this Guaranty or any transaction
         contemplated herein is, and all other such information (taken as a
         whole) hereafter furnished by or on behalf of Parent Guarantor in
         writing to any 


                                       6
<PAGE>   7

         Purchaser will be, true and accurate in all material respects on the
         date as of which such information is dated or certified and not
         incomplete by omitting to state any material fact necessary to make
         such information (taken as a whole) not misleading at such time in
         light of the circumstances under which such information was provided.
         There is no fact known to Parent Guarantor which is reasonably likely
         to have a material adverse effect on the rights or remedies of the
         Purchasers or on the ability of any Credit Party to perform its
         respective obligations under any Credit Document to them, which has
         not been disclosed herein or in such other documents, certificates and
         statements furnished to the Trustee and the Purchasers for use in
         connection with the transactions contemplated hereby.

         (i) Financial Condition, Financial Statements. (i) On and as of the
         Effective Date, on a pro forma basis after giving effect to all
         Indebtedness incurred, and to be incurred, by the Credit Parties in
         connection herewith, (x) the sum of the assets, at a fair valuation, of
         Parent Guarantor on a consolidated basis taken as a whole will exceed
         its debts, (y) Parent Guarantor on a consolidated basis taken as a
         whole will not have incurred or intended to, or believe that it will,
         incur debts beyond its ability to pay such debts as such debts mature
         and (z) Parent Guarantor on a consolidated basis taken as it whole will
         not have unreasonably small capital with which to conduct its business.

         (ii) (A) The consolidated balance sheet of Parent Guarantor at December
         31, 1997 and the related consolidated statements of operations and cash
         flows of Parent Guarantor for the fiscal year, as the case may be,
         ended as of said date, which have been examined by Price Waterhouse
         LLP, independent certified public accountants, who delivered an
         unqualified opinion in respect thereto, and (B) the consolidated
         balance sheet of Parent Guarantor as of March 31, 1998, copies of which
         have heretofore been furnished to each Purchaser, present fairly the
         financial position of such entities at the dates of said statements and
         the results for the period covered thereby in accordance with GAAP,
         except to the extent provided in the notes to said financial statements
         and, in the case of the March 31, 1998 statements, subject to normal
         and recurring year-end audit adjustments. All such financial statements
         have been prepared in accordance with generally accepted accounting
         principles and practices consistently applied except to the extent
         provided in the notes to said financial statements. Nothing has
         occurred since December 31, 1997 that has had or is reasonably likely
         to have a material adverse effect on the rights or remedies of the
         Purchasers hereunder, or on the ability of Parent Guarantor to perform
         its obligations to them.

         (iii) Except as reflected in the financial statements and the notes
         thereto described in clause (ii) above, there were as of the Effective
         Date no liabilities or obligations with respect to Parent Guarantor of
         a nature (whether absolute, accrued, contingent or otherwise and
         whether or not due) which, either individually or in aggregate, would
         be material to Parent Guarantor on a consolidated basis and its
         Subsidiaries taken as a whole, except as incurred subsequent to March
         31, 1998 in the ordinary course of business consistent with past
         practices. 


                                       7
<PAGE>   8


         (j) Tax Returns and Payments. The Parent Guarantor and each of its
         Subsidiaries has filed all federal income tax returns and all other
         material tax returns, domestic and foreign, required to be filed by it
         and has paid all material taxes and assessments payable by it which
         have become due, other than those not yet delinquent and except for
         those contested in good faith. The Parent Guarantor and each of its
         Subsidiaries has paid, or has provided adequate reserves (in the good
         faith judgment of the management of the Parent Guarantor) for the
         payment of, all federal, state and foreign income taxes applicable for
         all prior fiscal years and for the current fiscal year to the date
         hereof.

         (k) Employee Benefit Plans. (i) Neither the Parent Guarantor nor any of
         its Subsidiaries nor any ERISA Affiliate has ever maintained or
         contributed to (or had an obligation to contribute to) any Plan or any
         Foreign Pension Plan where any current or reasonably foreseeable
         liability of the Parent Guarantor or any of its Subsidiaries with
         respect to such Plan or such Foreign Pension Plan would be reasonably
         likely to have a Material Adverse Effect. All contributions required to
         be made with respect to (x) any employee pension benefit plan (as
         defined in Section 3(2) of ERISA) maintained or contributed to by (or
         to which there is an obligation to contribute of) the Parent Guarantor,
         any of its Subsidiaries or an ERISA Affiliate and (y) any Foreign
         Pension Plan have been timely made except any such failures to
         contribute which would not individually or in the aggregate be
         reasonably likely to have a Material Adverse Effect. The Parent
         Guarantor and its Subsidiaries may cease contributions to or terminate
         any employee benefit plan (within the meaning of Section 3(3) of ERISA)
         maintained or contributed to by (or to which there is an obligation to
         contribute of) them without incurring any liability which, individually
         or in the aggregate would be reasonably likely to have a Material
         Adverse Effect.

         (ii) Each Foreign Pension Plan his been maintained in material
         compliance with its terms and with the requirements of any and all
         applicable laws, statutes, rules, regulations and orders and has been
         maintained, where required, in good standing with applicable regulatory
         authorities.

         (1) Pollution and Other Regulations. (i) The Parent Guarantor and its
         Subsidiaries are in compliance with all applicable Environmental Laws
         governing its business for which failure to comply is reasonably likely
         to have a Material Adverse Effect, and neither the Parent Guarantor nor
         any of its Subsidiaries are liable for any material penalties, fines or
         forfeitures for failure to comply with any of the foregoing. All
         licenses, permits, registrations or approvals required for the business
         of the Parent Guarantor and its Subsidiaries, as conducted as of the
         Effective Date, under any Environmental Law have been secured and the
         Parent Guarantor and its Subsidiaries are in compliance therewith,
         except such licenses, permits, registrations or approvals the failure
         to secure or to comply therewith is not likely to have a Material
         Adverse Effect. The Parent Guarantor and its Subsidiaries are not in
         any respect in noncompliance with, breach of or default under any
         applicable writ, order, judgment, injunction, or decree to which the
         Parent Guarantor or 


                                       8
<PAGE>   9

         any such Subsidiary is a party or which would affect the ability of
         the Parent Guarantor and its Subsidiaries to operate the Mortgaged
         Rigs or any facility and no event has occurred and is continuing
         which, with the passage of time or the giving of notice or both, would
         constitute noncompliance, breach of or default thereunder, except in
         each such case, such noncompliance, breaches or defaults as are not
         likely to, in the aggregate, have a Material Adverse Effect. There are
         as of the Effective Date, no Environmental Claims pending or, to the
         knowledge, after due inquiry, of the Parent Guarantor, threatened,
         against the Parent Guarantor or any of its Subsidiaries wherein an
         unfavorable decision, ruling or finding would be reasonably likely to
         have a Material Adverse Effect. There are no facts, circumstances,
         conditions or occurrences on any real property, drilling rig or
         facility owned or operated by the Parent Guarantor or any of its
         Subsidiaries that is reasonably likely (x) to form the basis of an
         Environmental Claim against the Parent Guarantor, any Mortgaged Rig or
         facility owned by any Credit Party, or (y) to cause the Vessel or
         facility to be subject to any restrictions on its ownership,
         occupancy, use or transferability under any Environmental Law, except
         in each such case, such Environmental Claims or restrictions that
         individually or in the aggregate are not reasonably likely to have a
         Material Adverse Effect.

         (ii) Hazardous Materials have not at any time been (x) generated, used,
         treated or stored on, or transported to or from, any drilling rig or
         facility including the Mortgaged Rigs at any time owned or operated by
         the Parent Guarantor or any of its Subsidiaries or (y) released on or
         from any such drilling rig or facility, in each case where, to the
         Parent Guarantor's knowledge, after due inquiry, such occurrence or
         event individually or in the aggregate is reasonably likely to have a
         Material Adverse Effect.

         (m) Properties. The Parent Guarantor and its Subsidiaries have title to
         all material properties owned by them , free and clear of all Liens,
         other than Permitted Liens.

         (n) Labor Relations. Neither the Parent Guarantor nor any of its
         Subsidiaries is engaged in any unfair labor practice that is reasonably
         likely to have a Material Adverse Effect. There is (i) no unfair labor
         practice complaint pending against the Parent Guarantor or any of its
         Subsidiaries or threatened against the Parent Guarantor or any of its
         Subsidiaries, before the National Labor Relations Board, and no
         grievance or arbitration proceeding arising out of or under any
         collective bargaining agreement is pending; against the Parent
         Guarantor or any of its Subsidiaries or, to the Parent Guarantor's
         knowledge, after due inquiry, threatened against any of them, (ii) no
         strike, labor dispute, slowdown or stoppage is pending against the
         Parent Guarantor or any of its Subsidiaries or, to the Parent
         Guarantor's knowledge, after due inquiry, threatened against the Parent
         Guarantor or any of its Subsidiaries and (iii) no union representation
         petition existing with respect to the employees of the Parent Guarantor
         or its Subsidiaries and no union organizing activities are taking
         place, except with respect to any matter specified in clause (i), (ii)
         or (iii) above, either individually or in the aggregate, such as is not
         reasonably likely to have a Material Adverse Effect. 


                                       9
<PAGE>   10


         (o) Rig Classification. Each Mortgaged Rig is classified in the
         highest class available for rigs of its age and type with the American
         Bureau of Shipping, Inc, Bureau Veritas, Det Norske Veritas, Lloyd's
         Register of Shipping, or another internationally recognized
         classification society reasonably acceptable to the Trustee, free of
         any material requirements or recommendations, provided that the Vessel
         may be out of class as a result of, and pending the completion of the
         Project.

         (p) Patents, etc. The Parent Guarantor has obtained all patents,
         trademarks, service marks, trade names, copyrights, licenses and other
         rights, free from burdensome restrictions, that are necessary for the
         operation of its business taken as a whole as presently conducted, and
         Parent Guarantor knows of no such rights the absence of which would be
         reasonably likely to have a Material Adverse Effect.

         (q) Representations In Mortgages. The Parent Guarantor hereby confirms
         each representation and warranty of the Company and NACL set forth in
         the Mortgages.

         11. Affirmative Covenants. Parent Guarantor covenants and agrees that
on the Effective Date and thereafter for so long as this Agreement is in effect
and until the Notes (together with interest), Fees and all other Obligations
incurred hereunder, are irrevocably paid in full:

         (a) Information Covenants. Parent Guarantor will furnish to the Trustee
         (with sufficient copies for each of the Purchasers, and the Trustee
         will promptly forward to each of the Purchasers):

                  (i) Annual Financial Statements. Within 120 days after the
         close of each fiscal year of Parent Guarantor, the consolidated balance
         sheet of Parent Guarantor and its Subsidiaries, as at the end of such
         fiscal year and the related consolidated statements of income and
         retained earnings and of cash flows for such fiscal year, in each case
         setting forth comparative consolidated figures for the preceding fiscal
         year, and examined by independent certified public accountants of
         recognized national standing whose opinion shall not be qualified as to
         the scope of audit and as to the status of Parent Guarantor and its
         Subsidiaries as a going concern shall state that such financial
         statements present fairly, in all material respects, the financial
         position of the companies being reported upon and their results of
         operations and cash flows and have been prepared in conformity with
         GAAP, and that the examination of such accountants in connection with
         such financial statements has been made in accordance with generally
         accepted auditing standards, and that such audit provides a reasonable
         basis for such opinion in the circumstances. Such opinion shall be
         accompanied by a certificate of such accountants stating that they have
         reviewed this Agreement and stating further whether, in making their
         audit, they have become aware of any condition or event that then
         constitutes a Default or an Event of Default, and, if they are aware
         that any such condition or event then exists, specifying the nature and
         period of the existence thereof (it being understood that such
         accountants shall 


                                       10
<PAGE>   11


         not be liable, directly or indirectly, for any failure to obtain
         knowledge of any Default or Event of Default unless such accountants
         should have obtained knowledge thereof in making an audit in
         accordance with GAAP or did not make such an audit),

                  (ii) Quarterly Financial Statements. As soon as available and
         in any event within 60 days after the close of each of the first three
         quarterly accounting periods in each fiscal year, the consolidated
         balance sheet of Parent Guarantor and its Subsidiaries, as at the end
         of such quarterly period and the related consolidated statements of
         income and retainer earnings and of cash flows for such quarterly
         period and for the elapsed portion of the fiscal year ended with the
         last day of such quarterly period, in each case setting forth
         comparative consolidated figures for the related period in the prior
         fiscal year, subject to changes resulting from audit and normal
         year-end audit adjustments.

                  (iii) Compliance Certificate. At the time of the delivery of
         the financial statements provided for in clauses (i) and (ii) above, a
         certificate of Parent Guarantor signed by its Senior Vice
         President-Finance, Controller or other Authorized Officer setting forth
         the calculations required to establish whether Parent Guarantor was in
         compliance with the provisions of Section 12 hereof as at the end of
         such fiscal period or year, as the case may be.

                  (iv) Notices. Promptly, and in any event (i) within ten
         Business Days after Parent Guarantor obtains knowledge thereof, notice
         of the commencement of or any significant development in any litigation
         or governmental proceeding pending against Parent Guarantor which is
         likely to have a Material Adverse Effect or (ii) within five days after
         Parent Guarantor obtains knowledge thereof, notice of any Default or
         Event of Default or a default or event of default under the Parent
         Guaranty.

                  (v) Other Information. From time to time, such other
         information or documents (financial or otherwise) as the Trustee or any
         Purchaser may reasonably request.

         (b) Books, Records, Inspection. The Parent Guarantor will, upon
         reasonable notice to the Senior Vice President-Finance, Controller or
         any other Authorized Officer of the Parent Guarantor, permit officers
         and designated representatives of the Trustee (at the expense of the
         Trustee, but after the occurrence and during the continuance of a
         Default or any Event of Default, at the expense of the Parent
         Guarantor) or any Purchaser (at the expense of such Purchaser but after
         the occurrence and during the continuance of a Default or an Event of
         Default at the expense of the Parent Guarantor), to the extent
         necessary, to examine the books of account of the Parent Guarantor and
         discuss the affairs, finances and accounts of the Parent Guarantor
         with, and be advised as to the same by, its and their officers and
         independent accountants, all at such reasonable times and intervals and
         to such reasonable extent as the Trustee or the Purchaser may desire.


                                       11
<PAGE>   12


         (c) Maintenance of Property; Insurance. There will at all times be
         maintained in full force and effect insurance on the Mortgaged Rigs in
         such amounts with carriers of such insurance industry ratings, covering
         such risks and liabilities and with such deductibles or self-insured
         retentions as are in accordance with normal industry practice for
         similarly situated insureds.

         (d) Payment of Taxes. The Parent Guarantor will and will cause each of
         its Subsidiaries to pay and discharges all material taxes, assessments
         and governmental charges or levies imposed upon it or upon its income
         or profits, or upon any properties belonging to it or its Subsidiaries,
         prior to the date on which penalties attach thereto, and all lawful
         claims which, if unpaid, might become a Lien or charge upon any
         properties of the Parent Guarantor or its Subsidiaries, provided that
         the Company shall not be required to pay any such tax, assessment,
         charge, levy or claim which is being contested in good faith and by
         proper proceedings if it has maintained adequate reserves (in the good
         faith judgment of the management of the Parent Guarantor) with respect
         thereto.

         (e) Consolidated Corporate Franchises. The Parent Guarantor will do,
         and will cause each Credit Party to do, all things necessary to
         preserve and keep in full force and effect its corporate existence,
         material rights and authority, unless the failure to do so is not
         reasonably likely to have a Material Adverse Effect, provided that any
         transaction permitted by Section 7.02 of the Agreement will not
         constitute a breach of this clause (d).

         (f) Compliance with Statutes, etc. The Parent Guarantor and its
         Subsidiaries will comply with all applicable statutes, regulations and
         orders of, and all applicable restrictions imposed by, all governmental
         bodies, domestic or foreign, in respect of the conduct of their
         business and the ownership of their property other than those the
         non-compliance with which would not have a Material Adverse Effect or
         would not have a material adverse effect on the ability of any Credit
         Party to perform its business or its respective obligations under any
         Credit Document to which it is a party.

         (g) Good Repair. Except in the event any Mortgaged Rig has been damaged
         or has suffered a casualty as to which (within a reasonable period of
         time) management has not made a determination whether to replace or
         repair, or if the determination to replace or repair has been made, as
         to which such replacement or repairs are being undertaken, subject to
         availability of equipment, materials and/or repair facilities, the
         Parent Guarantor will, and will cause each Credit Party to, keep the
         Mortgaged Rigs, in whomsoever's possession they may be, in good repair,
         working order and condition, normal wear and tear excepted, and,
         subject to Section 7.02 of the Agreement, see that from time to time
         there are made in such properties and equipment all needful and proper
         repairs, renewals, replacements, extensions, additions, betterments and
         improvements thereto, (i) to the extent and in the manner useful or
         customary for companies in similar businesses and (ii) to the extent
         the failure to do so is reasonably likely to cause a Material Adverse
         Effect. 


                                       12
<PAGE>   13


         (h) End of Fiscal Years, Fiscal Quarters. The Parent Guarantor will,
         for financial reporting purposes, cause (i) its and its Subsidiaries
         fiscal years to end on December 31 of each year and (ii) its fiscal
         quarters to end on March 31, June 30, September 30 and December 31 of
         each year.

         (i) ERISA. As soon as possible and, in any event, within 10 days after
         the Parent Guarantor, any of its Subsidiaries or any ERISA Affiliate
         knows or has reason to know that: (a) a material contribution required
         to be made with respect to (i) any employee pension benefit plan (as
         defined in Section 3(2) of ERISA) maintained or contributed to by (or
         to which there is an obligation to contribute to the Parent Guarantor,
         any of its Subsidiaries or an ERISA Affiliate or (ii) any Foreign
         Pension Plan has not been timely made or (b) the Parent Guarantor or
         any of its Subsidiaries may incur any material liability pursuant to
         any employee welfare benefit plan (as defined in Section 3(l) of ERISA)
         that provides benefits to retired employees or other former employees
         (other than as required by Section 601 of ERISA) or any employee
         pension benefit plan (as defined in Section 3(2) of ERISA), the Parent
         Guarantor or the Company will deliver to each of the Purchasers a
         certificate of the Senior Vice President-Finance or Controller of the
         Parent Guarantor setting forth details as to such occurrence and the
         action, if any, that the Parent Guarantor, such Subsidiary or such
         ERISA Affiliate is required or proposes to take, together with any
         notices required or proposed to be given to or filed with or by the
         Parent Guarantor, such Subsidiary, the ERISA Affiliate, a plan
         participant or the plan administrator.

         (j) Further Assurances. (i) The Parent Guarantor will, and will cause
         each other Credit Party to, at the expense of such Credit Party, make,
         execute, endorse, acknowledge, file and/or deliver to the Trustee, from
         time to time such vouchers, invoices, schedules, confirmatory
         assignments, conveyances, financing statements, transfer endorsements,
         power of attorney, certificates, real property surveys, reports and
         other assurances or instruments and take such further steps relating to
         the Trustee or any Purchaser may reasonably require.

                  (ii) The Parent Guarantor agrees that each action required
         above by this clause (i) shall be completed as soon as possible, but in
         no event later than 30 days after such action is requested to be taken
         by the Trustee or the Required Purchasers, provided that in no event
         shall the Parent Guarantor or any of its Subsidiaries be required to
         take any action, other than using its reasonable commercial efforts
         without any material expenditure, to obtain consents or other actions
         from third parties with respect to its compliance with this clause (i).

         12. Negative Covenants. Parent Guarantor hereby covenants and agrees
that as of the Effective Date and thereafter for so long as this Guaranty is in
effect and until all Obligations guaranteed hereunder are irrevocably paid in
full:


                                       13
<PAGE>   14


         (a) Changes in Business. The Parent Guarantor will not materially alter
         the character of its business taken as a whole from that conducted at
         the Effective Date.

         (b) Consolidation, Merger, Sale of Assets, etc. The Parent Guarantor
         will not and will not permit any Credit Party to wind up, liquidate or
         dissolve its affairs, or enter into any transaction of merger or
         consolidation, sell or otherwise dispose of all or any part of the
         Collateral or agree to do any of the foregoing at any future time,
         except that the following shall be permitted:

                  (i) any Subsidiary Guarantor may be merged into the Parent
         Guarantor or any other Credit Party and the Company may be merged into
         the Parent Guarantor; provided, however, that the surviving company
         shall have assumed the obligations of the Subsidiary Guarantor under
         the Subsidiary Guaranty in writing and shall have delivered to the
         Trustee an opinion of counsel to the effect that the obligations of the
         Subsidiary Guarantor under the Subsidiary Guaranty have been duly and
         validly assumed and constitute valid and binding obligations of the
         surviving company enforceable in accordance with their terms; and

                  (ii) so long as no Default or Event of Default exists or would
         result therefrom, on or after June 1, 2001 the Credit Parties may sell
         the Mortgaged Rigs for cash at fair market value, provided that the
         proceeds of any such disposition shall be applied to prepay the Notes
         in full in accordance with Section 3.01 of the Agreement.

         (c) Interest Coverage Ratio. The Parent Guarantor shall not permit the
         ratio at the end of each fiscal quarter of (i) Adjusted Consolidated
         EBITDA to (ii) Consolidated Interest Expense for the period of the four
         most recently completed consecutive fiscal quarters of the Company to
         be less than 3.00:1.00.

         (d) Leverage Ratio. The Parent Guarantor shall not permit the Leverage
         Ratio as of the end of any fiscal quarter to be more than 0.40:1.00.

         (e) Net Worth. The Parent Guarantor shall not permit Consolidated Net
         Worth as of the end of any fiscal quarter to be less than $812,382,000
         plus 50% of Consolidated Net Income (determined on a cumulative basis)
         for all Cumulative Net Income Periods ending prior to the date of
         determination for which Consolidated Net Income was a positive number.

         13.      Miscellaneous.

         (a) Calculations, Computations. (a) The financial statements to be
         furnished to the Purchasers pursuant hereto shall be made and prepared
         in accordance with GAAP consistently applied throughout the periods
         involved (except as set forth in the notes thereto or as otherwise
         disclosed in writing by Parent Guarantor to the Purchasers),


                                       14
<PAGE>   15


         provided that (x) except as otherwise specifically provided herein,
         all computations determining compliance with Section 12, including
         definitions used therein, shall utilize accounting principles and
         policies in effect at the time of the preparation of, and in
         conformity with those used to prepare, the December 31, 1997 and March
         31, 1998 historical financial statements of the Company delivered to
         the Purchasers pursuant to Section 10(i), and (y) that if at any time
         the computations determining compliance with Section 12 utilize
         accounting principles different from those utilized in the financial
         statements furnished to the Purchasers, such financial statements
         shall be accompanied by reconciliation work-sheets.

         (b) Notices. All notices and other communications provided for
         hereunder shall be given as set forth in the Agreement (i) to Guarantor
         at the address set forth below its execution hereof, and (ii) to
         Trustee and/or Purchasers at the addresses set forth in the Agreement.

         (c) Benefit of Agreement. This Guaranty shall be binding upon and inure
         to the benefit of and be enforceable by the respective successors and
         assigns of the parties hereto, provided that Parent Guarantor may not
         assign or transfer any of its rights or obligations hereunder without
         the prior written consent of the Purchasers.

         (d) Governing Law, Submission to Jurisdiction, Venue; Waiver of Jury 
         Trial.

                  (i) THIS GUARANTY AND THE RIGHTS AND OBLIGATIONS OF THE
         PARTIES HEREUNDER AND THEREUNDER SHALL BE CONSTRUED IN ACCORDANCE WITH
         AND BE GOVERNED BY THE INTERNAL LAW OF THE STATE OF NEW YORK. Any legal
         action or proceeding with respect to this Guaranty may be brought in
         the courts of the state of New York or of the United States for the
         Southern District of New York, and, by execution and delivery of this
         Guaranty, the Parent Guarantor hereby irrevocably accepts for itself
         and in respect of its property, generally and unconditionally, the
         non-exclusive jurisdiction of the aforesaid courts. The Parent
         Guarantor further irrevocably consents to the service of process out of
         any of the aforementioned courts in any such action or proceeding by
         the mailing of copies thereof by registered or certified mail, postage
         prepaid, to the Parent Guarantor located outside New York City and by
         hand delivery to the Company located within New York City, at its
         address for notices pursuant to Section 13(b) above, such service to
         become effective 7 days after such mailing. Nothing herein shall affect
         the right of the Trustee or any Purchaser to serve process in any other
         manner permitted by law or to commence legal proceedings or otherwise
         proceed against Parent Guarantor in any other jurisdiction.

                  (ii) The Parent Guarantor hereby irrevocably waives any
         objection which it may now or hereafter have to the laying of venue of
         any of the aforesaid actions or proceedings arising out of or in
         connection with this Guaranty brought in the courts referred to in
         clause (i) above and hereby further irrevocably waives and agrees not
         to 


                                       15
<PAGE>   16

         plead or claim in any such court that any such action or proceeding
         brought in any such court has been brought in an inconvenient forum.

                  (iii) The Parent Guarantor by its acceptance hereof, hereby
         irrevocably waives all right to a trial by jury in any action,
         proceeding or counterclaim arising out of or relating to this Guaranty
         or the transactions contemplated hereby.

         (e) Headings Descriptive. The headings of the several sections and
         subsections of this Guaranty are inserted for convenience only and
         shall not in any way affect the meaning or construction of any
         provision of this Guaranty.

         14. Definitions. As used herein, the following terms shall have the
following meanings (such meanings to be equally applicable to both the singular
and plural forms of the term defined):

                  "Adjusted Consolidated EBITDA" shall mean for any period,
         Consolidated EBITDA for such period, less cash dividends and cash taxes
         paid during such period.

                  "Capital Lease" as applied to any Person shall mean any lease
         of any property (whether real, personal or mixed) by that Person as
         lessee which, in conformity with GAAP, is accounted for as a capital
         lease on the balance sheet of that Person.

                  "Capitalized Lease Obligations" shall mean all obligations
         under Capital Leases of the Parent Guarantor or any of its Subsidiaries
         in each case taken at the amount thereof accounted for as liabilities
         in accordance with GAAP.

                  "Consolidated EBIT" shall mean, for any period, (A) the sum of
         the amounts for such period of (i) Consolidated Net Income, (ii)
         provisions for taxes based on income, (iii) Consolidated Interest
         Expense, (iv) amortization or write-off of deferred financing costs to
         the extent deducted in determining Consolidated Net Income and (v)
         losses on sales of assets (excluding sales in the ordinary course of
         business) and other extraordinary losses less (B) the amount for such
         period of gains on sales of assets (excluding sales in the ordinary
         course of business) and other extraordinary gains, all as determined on
         a consolidated basis in accordance with GAAP.

                  "Consolidated EBITDA" shall mean, for any period, the sum of
         the amounts for such period of (i) Consolidated EBIT, (ii) depreciation
         expense of the Parent Guarantor and its Subsidiaries and (iii)
         amortization expense of the Parent Guarantor and its Subsidiaries, all
         as determined on a consolidated basis in accordance with GAAP.

                  "Consolidated Indebtedness" shall mean, as at any date of
         determination, the aggregate stated balance sheet amount of all
         Indebtedness (including the Notes) of the Parent Guarantor and its
         Subsidiaries on a consolidated basis as determined in accordance


                                       16
<PAGE>   17

         with GAAP, excluding all Contingent Obligations relating to the
         Indebtedness of any Person which is included in the calculation of
         Consolidated Indebtedness of the Parent Guarantor and its
         Subsidiaries.

                  "Consolidated Interest Expense" shall mean, for any period,
         total interest expense (including that attributable to Capital Leases)
         of the Parent Guarantor and its Subsidiaries in accordance with GAAP on
         a consolidated basis with respect to all outstanding Indebtedness of
         the Parent Guarantor and its Subsidiaries, provided that for purposes
         of this definition only, "Indebtedness" shall be deemed to include all
         indebtedness of the Parent Guarantor and its Subsidiaries which is
         otherwise excluded pursuant to clause (y) of the proviso contained in
         the definition of "Indebtedness".

                  "Consolidated Net Income" shall mean for any period, the net
         income (or loss) of the Parent Guarantor and its Subsidiaries on a
         consolidated basis for such period taken as a single accounting period
         determined in conformity with GAAP.

                  "Consolidated Net Worth" shall mean, at any time,
         shareholder's equity of the Parent Guarantor and its Subsidiaries on a
         consolidated basis determined in accordance with GAAP.

                  "Contingent Obligations" shall mean as to any Person any
         obligation of such Person guaranteeing or intending to guarantee any
         Indebtedness, leases, dividends or other obligations ("primary
         obligations") of any other Person (the "primary obligor") in any
         manner. whether directly or indirectly, including, without limitation,
         any obligation of such Person, whether or not contingent, (a) to
         purchase any such primary obligation or any property constituting
         direct or indirect security therefor, (b) to advance or supply funds
         (i) for the purchase or payment of any such primary obligation or (ii)
         to maintain working capital or equity capital of the primary obligor or
         otherwise to maintain the net worth or solvency of the primary obligor,
         (c) to purchase Property, securities or services primarily for the
         purpose of assuring the owner of any such primary obligation of the
         ability of the primary obligor to make payment of such primary
         obligation or (d) otherwise to assure or hold harmless the owner of
         such primary obligation against loss in respect thereof, provided,
         however, that the term Contingent Obligation shall not include
         endorsements of instruments for deposit or collection in the ordinary
         course of business. The amount of any Contingent Obligation shall be
         deemed to be an amount equal to the stated or determinable amount of
         the primary obligation in respect of which such Contingent Obligation
         is made or, if not stated or determinable, the maximum reasonably
         anticipated liability in respect thereof (assuming such Person is
         required to perform thereunder) as determined by such Person in good
         faith.

                  "Cumulative Net Income Period" shall mean each period
         consisting of a fiscal quarter of the Company ending after March 31,
         1998.


                                       17
<PAGE>   18


                  "GAAP" shall mean generally accepted accounting principles in
         the United States of America as in effect from time to time.

                  "Indebtedness" of any Person shall mean without duplication
         (i) all indebtedness of such Person for borrowed money, (ii) the
         deferred purchase price of assets or services which in accordance with
         GAAP would be shown on the liability side of the balance sheet of such
         Person, (iii) the face amount of all letters of credit issued for the
         account of such Person and, without duplication, all drafts drawn
         thereunder, (iv) all Indebtedness of a second Person secured by any
         Lien on any property owned by such first Person, whether or not such
         indebtedness has been assumed, (v) all Capitalized Lease Obligations of
         such Person, (vi) all obligations of such Person to pay a specified
         purchase price for goods or services whether or not delivered or
         accepted, (vii) all net obligations of such Person under Interest Rate
         Agreements and (viii) all Contingent Obligations of such Person (other
         than Contingent Obligations arising from the guaranty by such Person of
         Permitted Indebtedness of the Company and/or its Subsidiaries) provided
         that Indebtedness shall not include (x) trade payables and accrued
         expenses, in each case arising in the ordinary course of business and
         (y) indebtedness incurred by non-Credit Party Subsidiaries of the
         Parent Guarantor which is non-recourse to the Parent Guarantor or any
         other Subsidiary of the Parent Guarantor.

                  "Interest Rate Agreement" shall mean any interest rate swap
         agreement, any interest rate cap agreement, any interest rate collar
         agreement or other similar agreement or arrangement designed to protect
         the Parent Guarantor against interest rate risk.

                  "Leverage Ratio" shall mean, at any date of determination, the
         ratio of Consolidated Indebtedness on such date to Total Capitalization
         on such date.

                  "Non-Recourse Subsidiary" shall mean any Subsidiary of the
         Parent Guarantor which is the obligor with respect to any Indebtedness
         which is excluded from the definition of "Indebtedness" pursuant to
         clause (y) of the proviso contained therein.

                  "Total Capitalization" shall mean, at any time, the sum of
         Consolidated Indebtedness and Consolidated Net Worth at such time.


                                       18
<PAGE>   19


         IN WITNESS WHEREOF, Parent Guarantor has caused multiple counterparts
of this Agreement to be duly executed and delivered as of the date first above
written.

                                        NOBLE DRILLING CORPORATION


                                        By: /s/ BYRON L. WELLIVER
                                           -------------------------------------
Address for Notices:                    Byron L. Welliver, Senior Vice President

10370 Richmond Avenue, Suite 400
Houston, TX 77042
Attn:    Byron L. Welliver
Telephone:  (713) 974-3131
Facsimile:  (713) 974-3181


                                        Accepted and Agreed to:

                                        CHASE BANK OF TEXAS,
                                        NATIONAL ASSOCIATION,
                                          as Trustee



                                        By: /s/ MAURI J. COWEN
                                           -------------------------------------
                                            Name: Mauri J. Cowen
                                            Title: Vice President and 
                                                   Trust Officer

                                       19

<PAGE>   1
                                                                     EXHIBIT 4.7


                                SECOND AMENDMENT


                  SECOND AMENDMENT (this "Amendment"), dated as of September 10,
1998, among NOBLE DRILLING CORPORATION, a Delaware corporation (the "Borrower"),
various lending institutions party to the Credit Agreement referred to below
(the "Banks"), CREDIT LYONNAIS NEW YORK BRANCH, as Documentation Agent and
CHRISTIANIA BANK OG KREDITKASSE ASA, NEW YORK BRANCH, as Administrative Agent
(the "Administrative Agent"). All capitalized terms used herein and not
otherwise defined shall have the meanings assigned such terms in the Credit
Agreement referred to below.

                             W I T N E S S E T H :

                  WHEREAS, the Borrower, the Banks and the Administrative Agent
are parties to a Credit Agreement, dated as of August 14, 1997 (as amended,
modified or supplemented to the date hereof, the "Credit Agreement");

                  WHEREAS, subject to the terms and conditions set forth herein,
the parties hereto wish to amend the Credit Agreement as herein provided;

                  NOW, THEREFORE, it is agreed:

                  1. Section 8.02(a) of the Credit Agreement is hereby amended
by inserting the following proviso at the end of clause (ii) thereof:

                  "provided that, at any time prior to December 31, 1998, the
Borrower and its Subsidiaries may transfer one or more of the Reserve Rigs to
foreign Subsidiaries of the Borrower to the extent such transfer or transfers
result(s) in demonstrable tax savings of not less than $1,000,000 to the
Borrower and its Subsidiaries taken as a whole,"

                  2. Section 8.03 of the Credit Agreement is hereby amended by
redesignating clause (h) thereof as clause (i) and inserting the following new
clause (h) immediately following clause (g) thereof:

                  (h) At any time after Ilion LLC shall become a Subsidiary of
the Borrower pursuant to a Permitted Investment, Ilion LLC shall be permitted to
incur up to $200,000,000 of Indebtedness to be used to upgrade, refit, refurbish
and/or repair the offshore drilling rig "Ilion", which Indebtedness may be
guaranteed by the Borrower; provided that (i) such Indebtedness shall not be
secured by any assets of the Borrower or any of its Subsidiaries other than the
"Ilion", the associated drilling contract referred to in clause (ii) below,
earnings from such contract and the insurances relating to the "Ilion", and (ii)
at the time of the incurrence of such Indebtedness, the "Ilion" shall be subject
to a binding letter of intent or executed multiyear drilling contract with a
reputable



<PAGE>   2



operator of recognized standing, which contract shall be reasonably expected, in
the good faith opinion of management, to provide income necessary to amortize at
least 80% of such Indebtedness; and

                  3. Section 8.04 of the Credit Agreement is hereby amended by
inserting the following clause (o) immediately following clause (n) thereof:

                  (o) Liens on the offshore drilling rig "Ilion", the associated
drilling contract, earnings from such contract and the insurances relating to
the "Ilion", to the extent such Liens are incurred pursuant to financing which
is permitted by Section 8.03(h).

                  4. Section 8.07(b) of the Credit Agreement is hereby amended
by inserting the following new language immediately prior to the period at the
end thereof:

                  "and (ii) the Borrower and the Guarantors may transfer the
Reserve Rigs to Subsidiaries which are not Guarantors to the extent permitted by
Section 8.02(a)(ii)".

                  5. Section 10 of the Credit Agreement is hereby amended by (i)
deleting the text of clause (j) of the definition of "Permitted Investments" in
its entirety and inserting the language "[Intentionally Omitted]" in lieu
thereof and (ii) deleting the reference to "10%" appearing in clause (k) of said
definition and inserting a reference to "20%" in lieu thereof.

                  6. Section 10 of the Credit Agreement is hereby further
amended by inserting the following new definition in appropriate alphabetical
order:

                  "Reserve Rigs" shall mean each of the offshore drilling rigs
"Noble Percy Johns", "Ed Noble", "Lloyd Noble" and "Tommy Craighead", in each
case as such rig is named on the date hereof.

                  7. In order to induce the Banks to enter into this Amendment,
the Borrower (i) agrees to pay to each Bank which executes a copy of this
amendment on or before 5:00 p.m. New York time on September 25, 1998 an
amendment fee (the "Amendment Fee") equal to .20% of such Bank's Commitment
immediately after giving effect to this Amendment, which fee shall be earned by
and payable to each such Bank concurrently with the occurrence of the Second
Amendment Effective Date and (ii) (x) represents and warrants that no Default or
Event of Default exists on the Second Amendment Effective Date (as hereinafter
defined) both before and after giving effect to this Amendment, and (y) makes
each of the representations, warranties and agreements contained in the Credit
Agreement and the other Credit Documents on and as of the Second Amendment
Effective Date both before and after giving effect to this Amendment (it being
understood that any representation or warranty which by its terms is made as of
a specified date shall be required to be true and correct in all material
respects as of such date).



<PAGE>   3



                  8. This Amendment is limited as specified and shall not
constitute a modification, acceptance or waiver of any other provision of the
Credit Agreement or any other Credit Document.

                  9. This Amendment may be executed in any number of
counterparts and by the different parties hereto on separate counterparts, each
of which counterparts when executed and delivered shall be an original, but all
of which shall together constitute one and the same instrument. A complete set
of counterparts shall be lodged with the Borrower and the Administrative Agent.

                  10. THIS AMENDMENT AND THE RIGHTS AND OBLIGATIONS OF THE
PARTIES HEREUNDER SHALL BE CONSTRUED IN ACCORDANCE WITH AND GOVERNED BY THE LAW
OF THE STATE OF NEW YORK.

                  11. This Amendment shall become effective on the first date
(the "Second Amendment Effective Date") on which (i) each of the Borrower and
the Required Banks shall have signed a counterpart hereof (whether the same or
different counterparts) and shall have delivered (including by way of
telecopier) the same to the Administrative Agent at its Notice Office and (ii)
the Borrower shall have paid the Amendment Fee to each Bank entitled thereto.
                  12. At all times on and after the Second Amendment Effective
Date, all references in the Credit Agreement and each of the Credit Documents to
the Credit Agreement shall be deemed to be references to the Credit Agreement
after giving effect to this Amendment.

                              *        *        *

         IN WITNESS WHEREOF, each of the parties hereto has caused a counterpart
of this Amendment to be duly executed and delivered as of the date first above
written.

                                         NOBLE DRILLING CORPORATION

                                         ---------------------------------------



                                         CHRISTIANIA BANK OG KREDITKASSE ASA,
                                         NEW YORK BRANCH, Individually and as
                                         Administrative Agent

                                         ---------------------------------------



                                         CREDIT LYONNAIS NEW YORK BRANCH,
                                         Individually and as Documentation Agent

                                         ---------------------------------------




<PAGE>   4





                                         BANK OF TOKYO-MITSUBISHI, LTD.,
                                         HOUSTON AGENCY

                                         -------------------------------------




                                         THE FUJI BANK LIMITED

                                         -------------------------------------



                                         KBC BANK N.V.

                                         -------------------------------------



                                         MEESPIERSON CAPITAL CORPORATION

                                         -------------------------------------



                                         ROYAL BANK OF CANADA

                                         -------------------------------------



                                         WELLS FARGO BANK (TEXAS) NATIONAL
                                         ASSOCIATION

                                         -------------------------------------



                                         WESTDEUTSCHE LANDESBANK
                                         GIROZENTRALE, NEW YORK BRANCH

                                         -------------------------------------



                                         THE BANK OF NOVA SCOTIA

                                         -------------------------------------



<PAGE>   5




                                         SKANDINAVISKA ENSKILDA BANKEN AB
                                         (Publ.)
                                        
                                         -------------------------------------


                                         THE SANWA BANK, LIMITED

                                         -------------------------------------


                                         FIRST NATIONAL BANK OF COMMERCE

                                         -------------------------------------


                                         DG BANK, New York Branch

                                         -------------------------------------








<PAGE>   1
                                                                    EXHIBIT 10.1


================================================================================


                              EMPLOYMENT AGREEMENT





                                 BY AND BETWEEN





                           NOBLE DRILLING CORPORATION



                                       AND



                                  JAMES C. DAY







                                October 22, 1998




================================================================================
<PAGE>   2



                              EMPLOYMENT AGREEMENT
                                TABLE OF CONTENTS

<TABLE>
<CAPTION>
                                                                                     Page
                                                                                     ----
<S>                                                                                  <C>
1.  Employment .................................................................      1

2.  Employment Term ............................................................      1
    (a) Term ...................................................................      1
    (b) Relationship Prior to Effective Date ...................................      1

3.  Positions and Duties .......................................................      2

4.  Compensation and Related Matters ...........................................      3
    (a) Base Salary ............................................................      3
    (b) Annual Bonus ...........................................................      3
    (c) Employee Benefits ......................................................      4
        (i)  Incentive, Savings, and Retirement Plans ..........................      4
        (ii) Welfare Benefit Plans .............................................      4
    (d) Expenses ...............................................................      4
    (e) Fringe Benefits ........................................................      4
    (f) Vacation ...............................................................      5

5.  Termination of Employment ..................................................      5
    (a) Death ..................................................................      5
    (b) Disability .............................................................      5
    (c) Termination by Company .................................................      5
    (d) Termination by Executive ...............................................      6
    (e) Notice of Termination ..................................................      7
    (f) Date of Termination ....................................................      7

6.  Obligations of the Company Upon Termination ................................      8
    (a) Good Reason or During the Window Period; Other Than for
        Cause, Death, or Disability ............................................      8
    (b) Death ..................................................................     10
    (c) Disability .............................................................     11
    (d) Cause; Other Than for Good Reason or During the Window
        Period .................................................................     11

7.  Certain Additional Payments by the Company .................................     12

8.  Representations and Warranties .............................................     14

9.  Confidential Information ...................................................     14
</TABLE>

                                       i

<PAGE>   3

<TABLE>
<CAPTION>
                                                                                     Page
                                                                                     ----
<S>                                                                                  <C>
10. Certain Definitions ........................................................     15
    (a) Effective Date .........................................................     15
    (b) Change of Control Period ...............................................     15
    (c) Change of Control ......................................................     15

11. Full Settlement ............................................................     17

12. No Effect on Other Contractual Rights ......................................     18

13. Indemnification; Directors and Officers Insurance ..........................     18

14. Injunctive Relief ..........................................................     18

15. Governing Law ..............................................................     18

16. Notices ....................................................................     18

17. Binding Effect; Assignment; No Third Party Benefit .........................     19

18. Miscellaneous ..............................................................     19
    (a) Amendment ..............................................................     19
    (b) Waiver .................................................................     20
    (c) Withholding Taxes ......................................................     20
    (d) Nonalienation of Benefits ..............................................     20
    (e) Severability ...........................................................     20
    (f) Entire Agreement .......................................................     20
    (g) Captions ...............................................................     20
    (h) References .............................................................     20
</TABLE>


                                       ii

<PAGE>   4



                              EMPLOYMENT AGREEMENT

         This EMPLOYMENT AGREEMENT (this "Agreement"), dated as of October 22,
1998, by and between NOBLE DRILLING CORPORATION, a Delaware corporation (the
"Company"), and JAMES C. DAY (the "Executive");

                                   WITNESSETH:

         WHEREAS, the Board of Directors of the Company (the "Board") has
determined that it is in the best interests of the Company and its stockholders
to assure that the Company will have the continued dedication of the Executive,
notwithstanding the possibility, threat, or occurrence of a Change of Control
(as defined in Paragraph 10(c)) of the Company; and

         WHEREAS, the Board believes it is imperative to diminish the inevitable
distraction of the Executive by virtue of the personal uncertainties and risks
created by a pending or threatened Change of Control and to encourage the
Executive's full attention and dedication to the Company currently and in the
event of any pending or threatened Change of Control, and to provide the
Executive with compensation and benefits upon a Change of Control which ensure
that the compensation and benefits expectations of the Executive will be
satisfied and which are competitive with those of other corporations; and

         WHEREAS, in order to accomplish these objectives, the Board has caused
the Company to enter into this Agreement;

         NOW, THEREFORE, in consideration of the premises and the mutual
covenants and agreements herein contained, and intending to be legally bound
hereby, the Company and the Executive hereby agree as follows:

         1. Employment. The Company agrees that the Company or an affiliated
company (as hereafter defined) will continue the Executive in its employ, and
the Executive agrees to remain in the employ of the Company or an affiliated
company, for the period set forth in Paragraph 2(a), in the positions and with
the duties and responsibilities set forth in Paragraph 3, and upon the other
terms and conditions herein provided. As used in this Agreement, the term
"affiliated company" shall include any company controlled by, controlling, or
under common control with the Company.

         2. Employment Term.

         (a) Term. The employment of the Executive by the Company as provided in
Paragraph 1 shall be for the period commencing on the Effective Date (as defined
in Paragraph 10 (a)) through and ending on the third anniversary of such date
(the "Employment Term").

         (b) Relationship Prior to Effective Date. The Executive and the Company
acknowledge that, except as may otherwise be provided under any written
agreement between the Executive and the Company other than this Agreement, the
employment of the Executive by the

                                        1

<PAGE>   5



Company is "at will" and, prior to the Effective Date, may be terminated by
either the Executive or the Company at any time. Moreover, if prior to the
Effective Date, the Executive's employment with the Company terminates, then the
Executive shall have no further rights under this Agreement. For purposes of
this Paragraph 2(b) only, the term Company shall mean and include the company
that employs Executive, whether Noble Drilling Corporation or an affiliated
company of Noble Drilling Corporation.

         3. Positions and Duties.

         (a) During the Employment Term, the Executive's position (including
status, offices, titles, and reporting requirements), duties, functions,
responsibilities, and authority shall be at least commensurate in all material
respects with the most significant of those held or exercised by or assigned to
the Executive in respect of the Company and its affiliated companies at any time
during the 120-day period immediately preceding the Effective Date.

         (b) During the Employment Term, the Executive shall devote the
Executive's full time, skill, and attention and the Executive's reasonable best
efforts during normal business hours to the business and affairs of the Company,
and in furtherance of the business and affairs of its affiliated companies, to
the extent necessary to discharge faithfully and efficiently the duties and
responsibilities delegated and assigned to the Executive herein or pursuant
hereto, except for usual, ordinary, and customary periods of vacation and
absence due to illness or other disability; provided, however, that the
Executive may (i) serve on industry-related, civic or charitable boards or
committees, (ii) with the approval of the Board, serve on corporate boards or
committees, (iii) deliver lectures, fulfill speaking engagements, or teach at
educational institutions, and (iv) manage the Executive's personal investments,
so long as such activities do not significantly interfere with the performance
and fulfillment of the Executive's duties and responsibilities as an employee of
the Company or an affiliated company in accordance with this Agreement and, in
the case of the activities described in clause (ii) of this proviso, will not,
in the good faith judgment of the Board, constitute an actual or potential
conflict of interest with the business of the Company or an affiliated company.
It is expressly understood and agreed that, to the extent that any such
activities have been conducted by the Executive during the term of the
Executive's employment by the Company or its affiliated companies prior to the
Effective Date consistent with the provisions of this Paragraph 3(b), the
continued conduct of such activities (or of activities similar in nature and
scope thereto) subsequent to the Effective Date shall not thereafter be deemed
to interfere with the performance and fulfillment of the Executive's duties and
responsibilities to the Company.

         (c) In connection with the Executive's employment hereunder, the
Executive shall be based at the location where the Executive was regularly
employed immediately prior to the Effective Date or any office which is the
headquarters of the Company and is less than 50 miles from such location,
subject, however, to required travel on the business of the Company to an extent
substantially consistent with the Executive's business travel obligations during
the three-year period immediately preceding the Effective Date.


                                        2

<PAGE>   6



         (d) All services that the Executive may render to the Company or any of
its affiliated companies in any capacity during the Employment Term shall be
deemed to be services required by this Agreement and consideration for the
compensation provided for herein.

         4. Compensation and Related Matters.

         (a) Base Salary. During the Employment Term, the Executive shall
receive an annual base salary ("Base Salary") at least equal to 12 times the
highest monthly base salary paid or payable, including any base salary that has
been earned but deferred, to the Executive by the Company and its affiliated
companies in respect of the 12-month period immediately preceding the month in
which the Effective Date occurs. The Base Salary shall be payable in
installments in accordance with the general payroll practices of the Company in
effect at the time such payment is made, but in no event less frequently than
monthly, or as otherwise mutually agreed upon. During the Employment Term, the
Executive's Base Salary shall be subject to such increases (but not decreases)
as may be determined from time to time by the Board in its sole discretion;
provided, however, that the Executive's Base Salary (i) shall be reviewed by the
Board no later than 12 months after the last salary increase awarded to the
Executive prior to the Effective Date and thereafter at least annually, with a
view to making such upward adjustment, if any, as the Board deems appropriate,
and (ii) shall be increased at any time and from time to time as shall be
substantially consistent with increases in base salary generally awarded in the
ordinary course of business to the Executive's peer executives of the Company or
any of its affiliated companies. Base Salary shall not be reduced after any such
increase. The term Base Salary as used in this Agreement shall refer to the Base
Salary as so increased. Payments of Base Salary to the Executive shall not be
deemed exclusive and shall not prevent the Executive from participating in any
employee benefit plans, programs, or arrangements of the Company and its
affiliated companies in which the Executive is entitled to participate. Payments
of Base Salary to the Executive shall not in any way limit or reduce any other
obligation of the Company hereunder, and no other compensation, benefit, or
payment to the Executive hereunder shall in any way limit or reduce the
obligation of the Company regarding the Executive's Base Salary hereunder.

         (b) Annual Bonus. In addition to Base Salary, the Executive shall be
awarded, in respect of each fiscal year of the Company ending during the
Employment Term, an annual bonus (the "Annual Bonus") in cash in an amount at
least equal to the Executive's highest aggregate bonus under all Company bonus
plans, programs, arrangements, and awards (including the Company's Short-Term
Incentive Plan and any successor plan), in respect of any fiscal year in the
three full fiscal year period ended immediately prior to the Effective Date
(annualized for any fiscal year consisting of less than 12 full months or with
respect to which the Executive has been employed by the Company for less than 12
full months) (such highest amount is hereinafter referred to as the "Recent
Annual Bonus"). Each such Annual Bonus shall be paid no later than the end of
the third month of the fiscal year next following the fiscal year in respect of
which the Annual Bonus is awarded, unless the Executive shall elect to defer the
receipt of such Annual Bonus.


                                        3

<PAGE>   7



         (c) Employee Benefits.

                      (i) Incentive, Savings, and Retirement Plans. During the
         Employment Term, the Executive shall be entitled to participate in all
         incentive, savings, and retirement plans, programs, and arrangements
         applicable generally to the Executive's peer executives of the Company
         and its affiliated companies, but in no event shall such plans,
         programs, and arrangements provide the Executive with incentive
         opportunities (measured with respect to both regular and special
         incentive opportunities, to the extent, if any, that such distinction
         is applicable), savings opportunities, and retirement benefit
         opportunities, in each case, less favorable, in the aggregate, than the
         most favorable of those provided by the Company and its affiliated
         companies for the Executive under such plans, programs, and
         arrangements as in effect at any time during the 120-day period
         immediately preceding the Effective Date or, if more favorable to the
         Executive, those provided generally at any time after the Effective
         Date to the Executive's peer executives of the Company and its
         affiliated companies.

                      (ii) Welfare Benefit Plans. During the Employment Term,
         the Executive and/or the Executive's family, as the case may be, shall
         be eligible to participate in and shall receive all benefits under all
         welfare benefit plans, programs, and arrangements provided by the
         Company and its affiliated companies (including, without limitation,
         medical, prescription, dental, disability, salary continuance, employee
         life, group life, accidental death, and travel accident insurance
         plans, programs, and arrangements) to the extent applicable generally
         to the Executive's peer executives of the Company and its affiliated
         companies, but in no event shall such plans, programs, and arrangements
         provide the Executive with welfare benefits that are less favorable, in
         the aggregate, than the most favorable of such plans, programs, and
         arrangements as in effect for the Executive at any time during the
         120-day period immediately preceding the Effective Date or, if more
         favorable to the Executive, those provided generally at any time after
         the Effective Date to the Executive's peer executives of the Company
         and its affiliated companies.

         (d) Expenses. During the Employment Term, the Executive shall be
entitled to receive prompt reimbursement for all reasonable expenses incurred by
the Executive in performing the Executive's duties and responsibilities
hereunder, in accordance with the most favorable policies, practices, and
procedures of the Company and its affiliated companies as in effect for the
Executive at any time during the 120-day period immediately preceding the
Effective Date or, if more favorable to the Executive, as in effect generally at
any time thereafter with respect to the Executive's peer executives of the
Company and its affiliated companies.

         (e) Fringe Benefits. During the Employment Term, the Executive shall be
entitled to fringe benefits, including, without limitation, tax and financial
planning services, payment of club dues, and, if applicable, use of an
automobile and payment of related expenses, in accordance with the most
favorable policies, practices, and procedures of the Company and its affiliated
companies as in effect for the Executive at any time during the 120-day period
immediately preceding the Effective Date or, if more favorable to the Executive,
as in effect generally at any

                                        4

<PAGE>   8



time after the Effective Date with respect to the Executive's peer executives of
the Company and its affiliated companies.

         (f) Vacation. During the Employment Term, the Executive shall be
entitled to paid vacation and such other paid absences, whether for holidays,
illness, personal time, or any similar purposes, in accordance with the most
favorable policies, practices, and procedures of the Company and its affiliated
companies as in effect for the Executive at any time during the 120-day period
immediately preceding the Effective Date or, if more favorable to the Executive,
as in effect generally at any time after the Effective Date with respect to the
Executive's peer executives of the Company and its affiliated companies.

         5. Termination of Employment.

         (a) Death. The Executive's employment shall terminate automatically
upon the Executive's death during the Employment Term.

         (b) Disability. If the Company determines in good faith that the
Disability (as defined below) of the Executive has occurred during the
Employment Term, the Company may give the Executive notice of its intention to
terminate the Executive's employment. In such event, the Executive's employment
hereunder shall terminate effective on the 30th day after receipt of such notice
by the Executive (the "Disability Effective Date"), provided that, within the
30-day period after such receipt, the Executive shall not have returned to
full-time performance of the Executive's duties. For purposes of this Agreement,
"Disability" shall mean the absence of the Executive from the Executive's duties
hereunder on a full-time basis for an aggregate of 180 days within any given
period of 270 consecutive days (in addition to any statutorily required leave of
absence and any leave of absence approved by the Company), as a result of
incapacity of the Executive, despite any reasonable accommodation required by
law, due to bodily injury or disease or any other mental or physical illness,
which will, in the opinion of a physician selected by the Company or its
insurers and acceptable to the Executive or the Executive's legal
representative, be permanent and continuous during the remainder of the
Executive's life.

         (c) Termination by Company. The Company may terminate the Executive's
employment hereunder for Cause (as defined below). For purposes of this
Agreement, "Cause" shall mean:

                      (i) the willful and continued failure of the Executive to
         perform substantially the Executive's duties hereunder (other than any
         such failure resulting from bodily injury or disease or any other
         incapacity due to mental or physical illness), after a written demand
         for substantial performance is delivered to the Executive by the Board
         or the Chief Executive Officer of the Company which specifically
         identifies the manner in which the Board or Chief Executive Officer
         believes the Executive has not substantially performed the Executive's
         duties; or


                                        5

<PAGE>   9



                      (ii) the willful engaging by the Executive in illegal
         conduct or gross misconduct that is materially and demonstrably
         detrimental to the Company, monetarily or otherwise.

For purposes of this provision, no act, or failure to act, on the part of the
Executive shall be considered "willful" unless done, or omitted to be done, by
the Executive in bad faith or without reasonable belief that the Executive's
action or omission was in the best interests of the Company. Any act, or failure
to act, based upon authority given pursuant to a resolution duly adopted by the
Board or upon the instructions of the Chief Executive Officer or another senior
officer of the Company or based upon the advice of counsel for the Company shall
be conclusively presumed to be done, or omitted to be done, by the Executive in
good faith and in the best interests of the Company. The cessation of employment
of the Executive shall not be deemed to be for Cause unless and until there
shall have been delivered to the Executive a copy of a resolution duly adopted
by the affirmative vote of not less than two-thirds of the entire membership of
the Board then in office at a meeting of the Board called and held for such
purpose (after reasonable notice is provided to the Executive and the Executive
is given an opportunity, together with counsel, to be heard before the Board)
finding that, in the good faith opinion of the Board, the Executive is guilty of
the conduct described in subparagraph (i) or (ii) above, and specifying the
particulars thereof in detail.

         (d) Termination by Executive. The Executive may terminate the
Executive's employment hereunder (i) at any time during the Employment Term for
Good Reason (as defined below) or (ii) during the Window Period (as defined
below) without any reason.

For purposes of this Agreement, the "Window Period" shall mean the 30-day period
immediately following the first anniversary of the Effective Date, and "Good
Reason" shall mean any of the following (without the Executive's express written
consent):

                      (i) the assignment to the Executive of any duties
         inconsistent in any respect with the Executive's position (including
         status, offices, titles, and reporting requirements), duties,
         functions, responsibilities, or authority as contemplated by Paragraph
         3(a) of this Agreement, or any other action by the Company that results
         in a diminution in such position, duties, functions, responsibilities,
         or authority, excluding for this purpose an isolated, insubstantial,
         and inadvertent action not taken in bad faith and which is remedied by
         the Company promptly after receipt of notice thereof given by the
         Executive;

                      (ii) any failure by the Company to comply with any of the
         provisions of Paragraph 4 of this Agreement, other than an isolated,
         insubstantial, and inadvertent action not taken in bad faith and which
         is remedied by the Company promptly after receipt of notice thereof
         given by the Executive;

                      (iii) the Company's requiring the Executive to be based at
         any office or location other than as provided in Paragraph 3(c) of this
         Agreement or the Company's

                                        6

<PAGE>   10



         requiring the Executive to travel on Company business to a
         substantially greater extent than during the three-year period
         immediately preceding the Effective Date;

                      (iv) any failure by the Company to comply with and satisfy
         Paragraph 17(c) of this Agreement; or

                      (v) any purported termination by the Company of the
         Executive's employment hereunder otherwise than as expressly permitted
         by this Agreement, and for purposes of this Agreement, no such
         purported termination shall be effective.

For purposes of this Paragraph 5(d), any good faith determination of "Good
Reason" made by the Executive shall be conclusive.

         (e) Notice of Termination. Any termination of the Executive's
employment hereunder by the Company or by the Executive (other than a
termination pursuant to Paragraph 5(a)) shall be communicated by a Notice of
Termination (as defined below) to the other party hereto. For purposes of this
Agreement, a "Notice of Termination" shall mean a notice which (i) indicates the
specific termination provision in this Agreement relied upon, (ii) in the case
of a termination for Disability, Cause, or Good Reason, sets forth in reasonable
detail the facts and circumstances claimed to provide a basis for termination of
the Executive's employment under the provision so indicated, and (iii) specifies
the Date of Termination (as defined in Paragraph 5(f) below); provided, however,
that, notwithstanding any provision in this Agreement to the contrary, a Notice
of Termination given in connection with a termination for Good Reason shall be
given by the Executive within a reasonable period of time, not to exceed 120
days, following the occurrence of the event giving rise to such right of
termination. The failure by the Company or the Executive to set forth in the
Notice of Termination any fact or circumstance which contributes to a showing of
Disability, Cause, or Good Reason shall not waive any right of the Company or
the Executive hereunder or preclude the Company or the Executive from asserting
such fact or circumstance in enforcing the Company's or the Executive's rights
hereunder.

         (f) Date of Termination. For purposes of this Agreement, the "Date of
Termination" shall mean the effective date of termination of the Executive's
employment hereunder, which date shall be (i) if the Executive's employment is
terminated by the Executive's death, the date of the Executive's death, (ii) if
the Executive's employment is terminated because of the Executive's Disability,
the Disability Effective Date, (iii) if the Executive's employment is terminated
by the Company for Cause or by the Executive for Good Reason, the date on which
the Notice of Termination is given, (iv) if the Executive's employment is
terminated pursuant to Paragraph 2(a), the date on which the Employment Term
ends pursuant to Paragraph 2(a) due to a party's delivery of a Notice of
Termination thereunder, and (v) if the Executive's employment is terminated for
any other reason, the date specified in the Notice of Termination, which date
shall in no event be earlier than the date such notice is given; provided,
however, that if within 30 days after any Notice of Termination is given, the
party receiving such Notice of Termination notifies the other party that a
dispute exists concerning the termination, the Date of Termination shall be the
date on which the dispute is finally determined, either by mutual written
agreement

                                        7

<PAGE>   11



of the parties or by a final judgment, order, or decree of a court of competent
jurisdiction (the time for appeal therefrom having expired and no appeal having
been perfected).

         6. Obligations of the Company Upon Termination.

         (a) Good Reason or During the Window Period; Other Than for Cause,
Death, or Disability. If, during the Employment Term, the Company shall
terminate the Executive's employment hereunder other than for Cause or
Disability or the Executive shall terminate the Executive's employment either
for Good Reason or without any reason during the Window Period:

                      (i) the Company shall pay to the Executive in a lump sum
         in cash within 30 days after the Date of Termination the aggregate of
         the following amounts:

                                  (A) the sum of (1) the Executive's Base Salary
                      through the Date of Termination to the extent not
                      theretofore paid, (2) the product of (x) the greater of
                      (I) the Recent Annual Bonus and (II) the Annual Bonus paid
                      or payable, including by reason of any deferral, to the
                      Executive (and annualized for any fiscal year consisting
                      of less than 12 full months or for which the Executive has
                      been employed by the Company for less than 12 full months)
                      in respect of the most recently completed fiscal year of
                      the Company during the Employment Term, if any (such
                      greater amount hereinafter referred to as the "Highest
                      Annual Bonus"), and (y) a fraction, the numerator of which
                      is the number of days in the current fiscal year through
                      the Date of Termination, and the denominator of which is
                      365, and (3) any compensation previously deferred by the
                      Executive (together with any accrued interest or earnings
                      thereon) and any accrued vacation pay, in each case to the
                      extent not theretofore paid (the sum of the amounts
                      described in clauses (1), (2), and (3) are hereinafter
                      referred to as the "Accrued Obligations"); and

                                  (B) an amount (such amount is hereinafter
                      referred to as the "Severance Amount") equal to the
                      product of (1) three and (2) the sum of (x) the
                      Executive's Base Salary and (y) the Highest Annual Bonus;
                      and

                                  (C) a separate lump-sum supplemental
                      retirement benefit (the amount of such benefit hereinafter
                      referred to as the "Supplemental Retirement Amount") equal
                      to the difference between (1) the actuarial equivalent
                      (utilizing for this purpose the actuarial assumptions
                      utilized with respect to the qualified defined benefit
                      retirement plan of the Company and its affiliated
                      companies in which the Executive is eligible to
                      participate (or any successor plan thereto) (the
                      "Retirement Plan") during the 120-day period immediately
                      preceding the Effective Date) of the benefit payable under
                      the Retirement Plan and any supplemental and/or excess
                      retirement plan of the Company and its affiliated
                      companies providing benefits for the Executive (the
                      "SERP") which the Executive would receive if the
                      Executive's employment continued at the compensation level
                      provided for in Paragraphs 4(a) and 4(b)(i) for the
                      remainder

                                        8

<PAGE>   12



                      of the Employment Term, assuming for this purpose that all
                      accrued benefits are fully vested and that benefit accrual
                      formulas are no less advantageous to the Executive than
                      those in effect during the 120-day period immediately
                      preceding the Effective Date, and (2) the actuarial
                      equivalent (utilizing for this purpose the actuarial
                      assumptions utilized with respect to the Retirement Plan
                      during the 120-day period immediately preceding the
                      Effective Date) of the Executive's actual benefit (paid or
                      payable), if any, under the Retirement Plan and the SERP;
                      and

                      (ii) for three years after the Executives's Date of
         Termination, or such longer period as any plan, program, or arrangement
         may provide, the Company shall continue benefits to the Executive
         and/or the Executive's family at least equal to those that would have
         been provided to them in accordance with the plans, programs, and
         arrangements described in Paragraph 4(c)(ii) if the Executive's
         employment had not been terminated, in accordance with the most
         favorable plans, programs, and arrangements of the Company as in effect
         and applicable generally to the Executive's peer executives of the
         Company and its affiliated companies and their families during the
         120-day period immediately preceding the Effective Date or, if more
         favorable to the Executive, as in effect generally at any time
         thereafter with respect to the Executive's peer executives of the
         Company and its affiliated companies and their families; provided,
         however, that if the Executive becomes reemployed with another employer
         and is eligible to receive medical or other welfare benefits under
         another employer provided plan, the medical and other welfare benefits
         described herein shall be secondary to those provided under such other
         plan during such applicable period of eligibility (such continuation of
         such benefits for the applicable period herein set forth is hereinafter
         referred to as "Welfare Benefit Continuation") (for purpose of
         determining eligibility of the Executive for retiree benefits pursuant
         to such plans, programs, and arrangements, the Executive shall be
         considered to have remained employed until three years after the Date
         of Termination and to have retired on the last day of such period); and

                      (iii) the Company shall, at its sole expense as incurred,
         provide the Executive with outplacement services the scope and provider
         of which shall be selected by the Executive in the Executive's sole
         discretion; and

                      (iv) with respect to all options to purchase Common Stock
         held by the Executive pursuant to a Company stock option plan on or
         prior to the Date of Termination, irrespective of whether such options
         are then exercisable, the Executive shall have the right, during the
         60-day period after the Date of Termination, to elect to surrender all
         or part of such options in exchange for a cash payment by the Company
         to the Executive in an amount equal to the number of shares of Common
         Stock subject to the Executive's option multiplied by the excess of (x)
         over (y), where (x) equals the highest reported sale price of a share
         of Common Stock in any transaction reported on the New York Stock
         Exchange during the 60-day period prior to and including the
         Executive's Date of Termination and (y) equals the purchase price per
         share covered by the option. Such cash payments shall be made within 30
         days after the date of the Executive's election; provided,

                                        9

<PAGE>   13



         however, that if the Executive's Date of Termination is within six
         months after the date of grant of a particular option held by the
         Executive and the Executive is subject to Section 16(b) of the
         Securities Exchange Act of 1934, as amended (the "Exchange Act"), any
         cash payments related thereto shall be made on the date which is six
         months and one day after the date of grant of such option to the extent
         necessary to prevent the imposition of the disgorgement provisions
         under Section 16(b). Notwithstanding the foregoing, if any right
         granted pursuant to the foregoing would make any change of control
         transaction ineligible for pooling of interests accounting treatment
         under APB No. 16 that but for this Section 6(a)(iv) would otherwise be
         eligible for such accounting treatment, the Executive shall receive
         shares of Common Stock with a fair market value equal to the cash that
         would otherwise be payable hereunder in substitution for the cash,
         provided that any such shares of Common Stock so delivered to the
         Executive shall be registered under the Securities Act of 1933, as
         amended; any options outstanding as of the Date of Termination and not
         then exercisable shall become fully exercisable as of the Executive's
         Date of Termination, and to the extent the Executive does not elect to
         surrender same for a cash payment (or the equivalent number of shares
         of Common Stock) as provided above, such options shall remain
         exercisable after the Executive's Date of Termination in accordance
         with the terms thereof; and restrictions applicable to any shares of
         Common Stock awarded to the Executive by the Company shall lapse, as of
         the date of the Executive's Date of Termination; and

                      (v) all club memberships and other memberships that the
         Company was providing for the Executive's use at the time Notice of
         Termination is given shall, to the extent possible, be transferred and
         assigned to the Executive at no cost to the Executive (other than
         income taxes owed), the cost of transfer, if any, to be borne by the
         Company; and

                      (vi) all benefits under the Noble Drilling Corporation
         1991 Stock Option and Restricted Stock Plan and any other similar
         plans, including any stock options or restricted stock held by the
         Executive, not already vested shall be 100% vested, to the extent such
         vesting is permitted under the Code; and

                      (vii) to the extent not theretofore paid or provided, the
         Company shall timely pay or provide to the Executive any other amounts
         or benefits required to be paid or provided or which the Executive is
         eligible to receive under any plan, program, policy, practice, or
         arrangement or contract or agreement of the Company and its affiliated
         companies (such other amounts and benefits hereinafter referred to as
         the "Other Benefits").

         (b) Death. If the Executive's employment is terminated by reason of the
Executive's death during the Employment Term, this Agreement shall terminate
without further obligations to the Executive's legal representatives under this
Agreement, other than for (i) payment of Accrued Obligations (which shall be
paid to the Executive's estate or beneficiary, as applicable, in a lump sum in
cash within 30 days of the Date of Termination) and the timely payment or
provision of the Welfare Benefit Continuation and the Other Benefits and (ii)
payment to the

                                       10

<PAGE>   14



Executive's estate or beneficiaries, as applicable, in a lump sum in cash within
30 days of the Date of Termination of an amount equal to the sum of the
Severance Amount and the Supplemental Retirement Amount. With respect to the
provision of Other Benefits, the term Other Benefits as used in this Section
6(b) shall include, without limitation, and the Executive's estate and/or
beneficiaries shall be entitled to receive, benefits at least equal to the most
favorable benefits provided by the Company and affiliated companies to the
estates and beneficiaries of peer executives of the Company and such affiliated
companies under such plans, programs, practices, and policies relating to death
benefits, if any, as in effect with respect to other peer executives and their
beneficiaries at any time during the 120-day period immediately preceding the
Effective Date or, if more favorable to the Executive's estate and/or the
Executive's beneficiaries, as in effect on the date of the Executive's death
with respect to other peer executives of the Company and its affiliated
companies and their beneficiaries.

         (c) Disability. If the Executive's employment is terminated by reason
of the Executive's Disability during the Employment Term, this Agreement shall
terminate without further obligations to the Executive, other than for (i)
payment of Accrued Obligations (which shall be paid to the Executive in a lump
sum in cash within 30 days of the Date of Termination) and the timely payment or
provision of the Welfare Benefit Continuation and the Other Benefits and (ii)
payment to the Executive in a lump sum in cash within 30 days of the Date of
Termination of an amount equal to the sum of the Severance Amount and the
Supplemental Retirement Amount. With respect to the provision of Other Benefits,
the term Other Benefits as used in this Section 6(c) shall include, without
limitation, and the Executive shall be entitled after the Disability Effective
Date to receive, disability and other benefits at least equal to the most
favorable of those generally provided by the Company and affiliated companies to
disabled executives and/or their families in accordance with such plans,
programs, practices, and policies relating to disability, if any, as in effect
generally with respect to other peer executives and their families at any time
during the 120-day period immediately preceding the Effective Date or, if more
favorable to the Executive and/or the Executive's family, as in effect at any
time thereafter generally with respect to other peer executives of the Company
and its affiliated companies and their families.

         (d) Cause; Other Than for Good Reason or During the Window Period. If
the Executive's employment is terminated for Cause during the Employment Term,
this Agreement shall terminate without further obligations to the Executive
other than the obligation to pay to the Executive Base Salary through the Date
of Termination plus the amount of any compensation previously deferred by the
Executive, in each case to the extent theretofore unpaid. If the Executive
voluntarily terminates the Executive's employment during the Employment Term,
excluding a termination either for Good Reason or without any reason during the
Window Period, this Agreement shall terminate without further obligations to the
Executive, other than for Accrued Obligations and the timely payment or
provision of the Other Benefits. In such case, all Accrued Obligations shall be
paid to the Executive in a lump sum in cash within 30 days of the Date of
Termination subject to applicable laws and regulations.


                                       11

<PAGE>   15



         7. Certain Additional Payments by the Company.

         (a) Notwithstanding any provision in this Agreement to the contrary and
except as set forth below, if it shall be determined that any payment or
distribution by the Company to or for the benefit of the Executive (whether paid
or payable or distributed or distributable pursuant to the terms of this
Agreement or otherwise, but determined without regard to any additional payments
required pursuant to this Paragraph 7) (a "Payment") would be subject to the
excise tax imposed by Section 4999 of the Code or any interest or penalties are
incurred by the Executive with respect to such excise tax (such excise tax,
together with any such interest and penalties, are hereinafter collectively
referred to as the "Excise Tax"), then the Executive shall be entitled to
receive an additional payment (a "Gross-Up Payment") in an amount such that
after payment by the Executive of all taxes (including any interest or penalties
imposed with respect to such taxes), including any income taxes (and any
interest and penalties imposed with respect thereto) and Excise Tax imposed upon
the Gross-Up Payment, the Executive retains an amount of the GrossUp Payment
equal to the Excise Tax imposed upon the Payments. Notwithstanding the foregoing
provisions of this Paragraph 7(a), if it shall be determined that the Executive
is entitled to a Gross-Up Payment, but that the Executive, after taking into
account the Payments and the Gross-Up Payment, would not receive a net after-tax
benefit of at least $50,000 (taking into account both income taxes and any
Excise Tax) as compared to the net after-tax proceeds to the Executive resulting
from an elimination of the Gross-Up Payment and a reduction of the Payments, in
the aggregate, to an amount (the "Reduced Amount") such that the receipt of
payments would not give rise to any Excise Tax, then no Gross-Up Payment shall
be made to the Executive and the Payments, in the aggregate, shall be reduced to
the Reduced Amount.

         (b) Subject to the provisions of Paragraph 7(c), all determinations
required to be made under this Paragraph 7, including whether and when a
Gross-Up Payment is required and the amount of such Gross-Up Payment and the
assumptions to be utilized in arriving at such determination, shall be made by
PricewaterhouseCoopers (the "Accounting Firm") or, as provided below, such other
certified public accounting firm as may be designated by the Executive, which
shall provide detailed supporting calculations both to the Company and the
Executive within 15 business days after the receipt of notice from the Executive
that there has been a Payment, or such earlier time as is requested by the
Company. If the Accounting Firm is serving as accountant or auditor for the
individual, entity, or group effecting the Change of Control, the Executive
shall have the option, in the Executive's sole discretion, to appoint another
nationally recognized accounting firm to make the determinations required
hereunder (which accounting firm shall then be referred to as the Accounting
Firm hereunder). All fees and expenses of the Accounting Firm shall be borne
solely by the Company. Any Gross-Up Payment, as determined pursuant to this
Paragraph 7, shall be paid by the Company to the Executive within five days of
the receipt of the Accounting Firm's determination. If the Accounting Firm
determines that no Excise Tax is payable by the Executive, it shall furnish the
Executive with a written opinion that failure to report the Excise Tax on the
Executive's applicable federal income tax return would not result in the
imposition of a negligence or similar penalty. Any determination by the
Accounting Firm shall be binding upon the Company and the Executive. As a result
of the uncertainty in the application of Section 4999 of the Code at the time of
the initial determination by the Accounting Firm hereunder, it is possible that
Gross-Up Payments that will not have been made by the Company

                                       12

<PAGE>   16



should have been made ("Underpayment"), consistent with the calculations
required to be made hereunder. If the Company exhausts its remedies pursuant to
Paragraph 7(c) and the Executive thereafter is required to make a payment of any
Excise Tax, the Accounting Firm shall determine the amount of the Underpayment
that has occurred and any such Underpayment shall be promptly paid by the
Company to or for the benefit of the Executive.

         (c) The Executive shall notify the Company in writing of any claim by
the Internal Revenue Service that, if successful, would require the payment by
the Company of the Gross-Up Payment (or an additional amount of Gross-Up
Payment) in the event the Internal Revenue Service seeks higher payment. Such
notification shall be given as soon as practicable but no later than 10 business
days after the Executive is informed in writing of such claim and shall apprise
the Company of the nature of such claim and the date on which such claim is
requested to be paid. The Executive shall not pay such claim prior to the
expiration of the 30-day period following the date on which it gives such notice
to the Company (or such shorter period ending on the date that any payment of
taxes with respect to such claim is due). If the Company notifies the Executive
in writing prior to the expiration of such period that it desires to contest
such claim, the Executive shall:

                      (i) give the Company any information reasonably requested
         by the Company relating to such claim;

                      (ii) take such action in connection with contesting such
         claim as the Company shall reasonably request in writing from time to
         time, including the acceptance of legal representation with respect to
         such claim by an attorney reasonably selected by the Company;

                      (iii) cooperate with the Company in good faith in order
         effectively to contest such claim; and

                      (iv) permit the Company to participate in any proceedings
         relating to such claim;

provided, however, that the Company shall bear and pay directly all costs and
expenses (including additional interest and penalties) incurred in connection
with such contest and shall indemnify and hold the Executive harmless, on an
after-tax basis, for any Excise Tax or income tax (including interest and
penalties with respect thereto) imposed as a result of such representation and
payment of costs and expenses. Without limitation of the foregoing provisions of
this Paragraph 7(c), the Company shall control all proceedings taken in
connection with such contest and, at its sole option, may pursue or forgo any
and all administrative appeals, proceedings, hearings, and conferences with the
taxing authority in respect of such claim and may, at its sole option, either
direct the Executive to pay the tax claimed and sue for a refund or contest the
claim in any permissible manner, and the Executive agrees to prosecute such
contest to a determination before any administrative tribunal, in a court of
initial jurisdiction, and in one or more appellate courts, as the Company shall
determine; provided, however, that if the Company directs the Executive to pay
such claim and sue for a refund, the Company shall advance the amount of such
payment to

                                       13

<PAGE>   17



the Executive, on an interest-free basis, and shall indemnify and hold the
Executive harmless, on an after-tax basis, from any Excise Tax or income tax
(including interest or penalties with respect thereto) imposed with respect to
such advance or with respect to any imputed income with respect to such advance;
and provided further that any extension of the statute of limitations relating
to payment of taxes for the taxable year of the Executive with respect to which
such contested amount is claimed to be due is limited solely to such contested
amount. Furthermore, the Company's control of the contest shall be limited to
issues with respect to which a Gross-Up Payment would be payable hereunder and
the Executive shall be entitled to settle or contest, as the case may be, any
other issue raised by the Internal Revenue Service or any other taxing
authority.

         (d) If, after the receipt by the Executive of an amount advanced by the
Company pursuant to Paragraph 7(c), the Executive becomes entitled to receive
any refund with respect to such claim, the Executive shall (subject to the
Company's complying with the requirements of Paragraph 7(c)) promptly pay to the
Company the amount of such refund (together with any interest paid or credited
thereon after taxes applicable thereto). If, after the receipt by the Executive
of an amount advanced by the Company pursuant to Paragraph 7(c), a determination
is made that the Executive shall not be entitled to any refund with respect to
such claim and the Company does not notify the Executive in writing of its
intent to contest such denial of refund prior to the expiration of 30 days after
such determination, then such advance shall be forgiven and shall not be
required to be repaid and the amount of such advance shall offset, to the extent
thereof, the amount of Gross-Up Payment required to be paid.

         8. Representations and Warranties.

         (a) The Company represents and warrants to the Executive that the
execution, delivery, and performance by the Company of this Agreement have been
duly authorized by all necessary corporate action of the Company and do not and
will not conflict with or result in a violation of any provision of, or
constitute a default under, any contract, agreement, instrument, or obligation
to which the Company is a party or by which it is bound.

         (b) The Executive represents and warrants to the Company that the
execution, delivery, and performance by the Executive of this Agreement do not
and will not conflict with or result in a violation of any provision of, or
constitute a default under, any contract, agreement, instrument, or obligation
to which the Executive is a party or by which the Executive is bound.

         9. Confidential Information. The Executive recognizes and acknowledges
that the Company's trade secrets and other confidential or proprietary
information, as they may exist from time to time, are valuable, special, and
unique assets of the Company's business, access to and knowledge of which are
essential to the performance of the Executive's duties hereunder. The Executive
confirms that all such trade secrets and other information constitute the
exclusive property of the Company. During the Employment Term and thereafter
without limitation of time, the Executive shall hold in strict confidence and
shall not, directly or indirectly, disclose or reveal to any person, or use for
the Executive's own personal benefit or for the benefit of anyone else, any
trade secrets, confidential dealings, or other confidential or proprietary
information of any kind, nature, or description (whether or not acquired,
learned, obtained, or developed by the

                                       14

<PAGE>   18



Executive alone or in conjunction with others) belonging to or concerning the
Company or any of its affiliated companies, except (i) with the prior written
consent of the Company duly authorized by its Board, (ii) in the course of the
proper performance of the Executive's duties hereunder, (iii) for information
(x) that becomes generally available to the public other than as a result of
unauthorized disclosure by the Executive or the Executive's affiliates or (y)
that becomes available to the Executive on a nonconfidential basis from a source
other than the Company or its affiliated companies who is not bound by a duty of
confidentiality, or other contractual, legal, or fiduciary obligation, to the
Company, or (iv) as required by applicable law or legal process. The provisions
of this Paragraph 9 shall continue in effect notwithstanding termination of the
Executive's employment hereunder for any reason.

         10. Certain Definitions.

         (a) Effective Date. The "Effective Date" shall mean the first date
during the Change of Control Period (as defined in Paragraph 10(b)) on which a
Change of Control occurs. Notwithstanding anything in this Agreement to the
contrary, if a Change of Control occurs and if the Executive's employment with
the Company is terminated prior to the date on which the Change of Control
occurs, and if it is reasonably demonstrated by the Executive that such
termination of employment (i) was at the request of a third party who has taken
steps reasonably calculated to effect a Change of Control or (ii) otherwise
arose in connection with or anticipation of a Change of Control, then for all
purposes of this Agreement the "Effective Date" shall mean the date immediately
prior to the date of such termination of employment.

         (b) Change of Control Period. The "Change of Control Period" shall mean
the period commencing on the date of this Agreement and ending on the third
anniversary of such date; provided, however, that commencing on the date one
year after the date hereof, and on each annual anniversary of such date (such
date and each annual anniversary thereof herein referred to as the "Renewal
Date"), the Change of Control Period shall be automatically extended so as to
terminate three years after such Renewal Date, unless at least 60 days prior to
the Renewal Date the Company shall give notice to the Executive that the Change
of Control Period shall not be so extended.

         (c) Change of Control. For purposes of this Agreement, a "Change of
Control" shall mean:

                      (i) the acquisition by any individual, entity, or group
         (within the meaning of Section 13(d)(3) or 14(d)(2) of the Exchange
         Act) (a "Person") of beneficial ownership (within the meaning of Rule
         13d-3 promulgated under the Exchange Act) of 15% or more of either (A)
         the then outstanding shares of common stock of the Company (the
         "Outstanding Company Common Stock") or (B) the combined voting power of
         the then outstanding voting securities of the Company entitled to vote
         generally in the election of directors (the "Outstanding Company Voting
         Securities"); provided, however, that for purposes of this subparagraph
         (c)(i) the following acquisitions shall not constitute a Change of
         Control: (w) any acquisition directly from the Company (excluding an
         acquisition by virtue of the exercise of a conversion privilege), (x)
         any acquisition by the Company,

                                       15

<PAGE>   19



         (y) any acquisition by any employee benefit plan (or related trust)
         sponsored or maintained by the Company or any corporation controlled by
         the Company, or (z) any acquisition by any corporation pursuant to a
         reorganization, merger, or consolidation, if, following such
         reorganization, merger, or consolidation, the conditions described in
         clauses (A), (B), and (C) of subparagraph (iii) of this Paragraph 10
         (c) are satisfied; or

                      (ii) individuals who, as of the date of this Agreement,
         constitute the Board (the "Incumbent Board") cease for any reason to
         constitute a majority of the Board; provided, however, that any
         individual becoming a director subsequent to the date hereof whose
         election, or nomination for election by the Company's stockholders, was
         approved by a vote of a majority of the directors then comprising the
         Incumbent Board shall be considered as though such individual were a
         member of the Incumbent Board, but excluding, for this purpose, any
         such individual whose initial assumption of office occurs as a result
         of either an actual or threatened election contest or other actual or
         threatened solicitation of proxies or consents by or on behalf of a
         Person other than the Board; or

                      (iii) consummation of a reorganization, merger, or
         consolidation of the Company, with or without approval by the
         stockholders of the Company, in each case, unless, following such
         reorganization, merger, or consolidation, (A) more than 50% of,
         respectively, the then outstanding shares of common stock of the
         corporation resulting from such reorganization, merger, or
         consolidation and the combined voting power of the then outstanding
         voting securities of such corporation entitled to vote generally in the
         election of directors is then beneficially owned, directly or
         indirectly, by all or substantially all of the individuals and entities
         who were the beneficial owners, respectively, of the Outstanding
         Company Common Stock and Outstanding Company Voting Securities
         immediately prior to such reorganization, merger, or consolidation in
         substantially the same proportions as their ownership, immediately
         prior to such reorganization, merger, or consolidation, of the
         Outstanding Company Common Stock and Outstanding Company Voting
         Securities, as the case may be, (B) no Person (excluding the Company,
         any employee benefit plan (or related trust) of the Company or such
         corporation resulting from such reorganization, merger, or
         consolidation, and any Person beneficially owning, immediately prior to
         such reorganization, merger, or consolidation, directly or indirectly,
         15% or more of the Outstanding Company Common Stock or Outstanding
         Company Voting Securities, as the case may be) beneficially owns,
         directly or indirectly, 15% or more of, respectively, the then
         outstanding shares of common stock of the corporation resulting from
         such reorganization, merger, or consolidation or the combined voting
         power of the then outstanding voting securities of such corporation
         entitled to vote generally in the election of directors, and (C) a
         majority of the members of the board of directors of the corporation
         resulting from such reorganization, merger, or consolidation were
         members of the Incumbent Board at the time of the execution of the
         initial agreement providing for such reorganization, merger, or
         consolidation; or

                      (iv) consummation of a sale or other disposition of all or
         substantially all the assets of the Company, with or without approval
         by the stockholders of the Company, other than to a corporation, with
         respect to which following such sale or other disposition,

                                       16

<PAGE>   20



         (A) more than 50% of, respectively, the then outstanding shares of
         common stock of such corporation and the combined voting power of the
         then outstanding voting securities of such corporation entitled to vote
         generally in the election of directors is then beneficially owned,
         directly or indirectly, by all or substantially all the individuals and
         entities who were the beneficial owners, respectively, of the
         Outstanding Company Common Stock and Outstanding Company Voting
         Securities immediately prior to such sale or other disposition in
         substantially the same proportion as their ownership, immediately prior
         to such sale or other disposition, of the Outstanding Company Common
         Stock and Outstanding Company Voting Securities, as the case may be,
         (B) no Person (excluding the Company, any employee benefit plan (or
         related trust) of the Company or such corporation, and any Person
         beneficially owning, immediately prior to such sale or other
         disposition, directly or indirectly, 15% or more of the Outstanding
         Company Common Stock or Outstanding Company Voting Securities, as the
         case may be) beneficially owns, directly or indirectly, 15% or more of,
         respectively, the then outstanding shares of common stock of such
         corporation or the combined voting power of the then outstanding voting
         securities of such corporation entitled to vote generally in the
         election of directors, and (C) a majority of the members of the board
         of directors of such corporation were members of the Incumbent Board at
         the time of the execution of the initial agreement or action of the
         Board providing for such sale or other disposition of assets of the
         Company; or

                      (v) approval by the stockholders of the Company of a
         complete liquidation or dissolution of the Company.

         11. Full Settlement.

         (a) There shall be no right of set off or counterclaim against, or
delay in, any payments to the Executive, or to the Executive's heirs or legal
representatives, provided for in this Agreement, in respect of any claim against
or debt or other obligation of the Executive or others, whether arising
hereunder or otherwise.

         (b) In no event shall the Executive be obligated to seek other
employment or take any other action by way of mitigation of the amounts payable
to the Executive under any of the provisions of this Agreement, and such amounts
shall not be reduced whether or not the Executive obtains other employment.

         (c) The Company agrees to pay as incurred, to the full extent permitted
by law, all costs and expenses (including attorneys' fees) that the Executive,
or the Executive's heirs or legal representatives, may reasonably incur as a
result of any contest (regardless of the outcome thereof) by the Company, the
Executive, or others of the validity or enforceability of, or liability under,
any provision of this Agreement, or any guarantee of performance thereof
(including as a result of any contest by the Executive, or the Executive's heirs
or legal representatives, about the amount of any payment pursuant to this
Agreement), plus in each case interest on any delayed payment at the applicable
federal rate provided for in Section 7872(f)(2) of the Code.


                                       17

<PAGE>   21



         12. No Effect on Other Contractual Rights. The provisions of this
Agreement, and any payment provided for hereunder, shall not reduce any amounts
otherwise payable to the Executive, or in any way diminish the Executive's
rights as an employee of the Company, whether existing on the date of this
Agreement or hereafter, under any employee benefit plan, program, or arrangement
or other contract or agreement of the Company providing benefits to the
Executive.

         13. Indemnification; Directors and Officers Insurance. The Company
shall (a) during the Employment Term and thereafter without limitation of time,
indemnify and advance expenses to the Executive to the fullest extent permitted
by the laws of the State of Delaware from time to time in effect and (b) during
the Employment Term, acquire and maintain directors and officers liability
insurance covering the Executive (and to the extent the Company desires, other
directors and officers of the Company and its affiliated companies) to the
extent it is available at commercially reasonable rates as determined by the
Board; provided, however, that in no event shall the Executive be entitled to
indemnification or advancement of expenses under this Paragraph 13 with respect
to any proceeding, or matter therein, brought or made by the Executive against
the Company other than one initiated by the Executive to enforce the Executive's
rights under this Paragraph 13. The rights of indemnification and to receive
advancement of expenses as provided in this Paragraph 13 shall not be deemed
exclusive of any other rights to which the Executive may at any time be entitled
under applicable law, the certificate of incorporation or bylaws of the Company,
any agreement, a vote of stockholders, a resolution of the Board, or otherwise.
The provisions of this Paragraph 13 shall continue in effect notwithstanding
termination of the Executive's employment hereunder for any reason.

         14. Injunctive Relief. In recognition of the fact that a breach by the
Executive of any of the provisions of Paragraph 9 will cause irreparable damage
to the Company for which monetary damages alone will not constitute an adequate
remedy, the Company shall be entitled as a matter of right (without being
required to prove damages or furnish any bond or other security) to obtain a
restraining order, an injunction, an order of specific performance, or other
equitable or extraordinary relief from any court of competent jurisdiction
restraining any further violation of such provisions by the Executive or
requiring the Executive to perform the Executive's obligations hereunder. Such
right to equitable or extraordinary relief shall not be exclusive but shall be
in addition to all other rights and remedies to which the Company may be
entitled at law or in equity, including without limitation the right to recover
monetary damages for the breach by the Executive of any of the provisions of
this Agreement.

         15. Governing Law. This Agreement shall be governed by and construed
and enforced in accordance with the laws of the State of Texas, without regard
to the principles of conflicts of laws thereof.

         16. Notices. All notices, requests, demands, and other communications
required or permitted to be given or made hereunder by either party hereto shall
be in writing and shall be deemed to have been duly given or made (i) when
delivered personally, (ii) when sent by telefacsimile transmission, or (iii)
five days after being deposited in the United States mail, first class
registered or certified mail, postage prepaid, return receipt requested, to the
party for which

                                       18

<PAGE>   22



intended at the following addresses (or at such other addresses as shall be
specified by the parties by like notice, except that notices of change of
address shall be effective only upon receipt):

             If to the Company, at:    Noble Drilling Corporation
                                       10370 Richmond Avenue, Suite 400
                                       Houston, Texas 77042
                                       Fax No.:  713-974-3181
                                       Attention: Chief Executive Officer

             If to the Executive, at:  James C. Day
                                       Noble Drilling Corporation
                                       10370 Richmond Avenue, Suite 400
                                       Houston, Texas 77042
                                       Fax No.: 713-974-3181

         17. Binding Effect; Assignment; No Third Party Benefit.

         (a) This Agreement is personal to the Executive and without the prior
written consent of the Company shall not be assignable by the Executive
otherwise than by will or the laws of descent and distribution. This Agreement
shall inure to the benefit of and shall be enforceable by the Executive's legal
representatives.

         (b) This Agreement shall inure to the benefit of and be binding upon
the Company and its successors and assigns.

         (c) The Company shall require any successor or assign (whether direct
or indirect, by purchase, merger, consolidation, or otherwise) to all or
substantially all the business and/or assets of the Company, by agreement in
writing in form and substance reasonably satisfactory to the Executive,
expressly, absolutely, and unconditionally to assume and agree to perform this
Agreement in the same manner and to the same extent that the Company would be
required to perform it if no such succession or assignment had taken place. As
used in this Agreement, the "Company" shall mean the Company as hereinbefore
defined and any successor or assign to its business and/or assets as aforesaid
which executes and delivers the agreement provided for in this Paragraph 17(c)
or which otherwise becomes bound by all the terms and provisions of this
Agreement by operation of law.

         (d) Nothing in this Agreement, express or implied, is intended to or
shall confer upon any person other than the parties hereto, and their respective
heirs, legal representatives, successors, and permitted assigns, any rights,
benefits, or remedies of any nature whatsoever under or by reason of this
Agreement.

         18. Miscellaneous.

         (a) Amendment. This Agreement may not be modified or amended in any
respect except by an instrument in writing signed by the party against whom such
modification or amendment is sought to be enforced. No person, other than
pursuant to a resolution of the Board

                                       19

<PAGE>   23



or a committee thereof, shall have authority on behalf of the Company to agree
to modify, amend, or waive any provision of this Agreement or anything in
reference thereto.

         (b) Waiver. Any term or condition of this Agreement may be waived at
any time by the party hereto which is entitled to have the benefit thereof, but
such waiver shall only be effective if evidenced by a writing signed by such
party, and a waiver on one occasion shall not be deemed to be a waiver of the
same or any other type of breach on a future occasion. No failure or delay by a
party hereto in exercising any right or power hereunder shall operate as a
waiver thereof nor shall any single or partial exercise thereof preclude any
other or further exercise thereof or the exercise of any other right or power.

         (c) Withholding Taxes. The Company may withhold from any amounts
payable under this Agreement such federal, state, local, or foreign taxes as
shall be required to be withheld pursuant to any applicable law or regulation.

         (d) Nonalienation of Benefits. The Executive shall not have any right
to pledge, hypothecate, anticipate, or in any way create a lien upon any
payments or other benefits provided under this Agreement; and no benefits
payable hereunder shall be assignable in anticipation of payment either by
voluntary or involuntary acts, or by operation of law, except by will or
pursuant to the laws of descent and distribution.

         (e) Severability. If any provision of this Agreement is held to be
invalid or unenforceable, (a) this Agreement shall be considered divisible, (b)
such provision shall be deemed inoperative to the extent it is deemed invalid or
unenforceable, and (c) in all other respects this Agreement shall remain in full
force and effect; provided, however, that if any such provision may be made
valid or enforceable by limitation thereof, then such provision shall be deemed
to be so limited and shall be valid and/or enforceable to the maximum extent
permitted by applicable law.

         (f) Entire Agreement. This Agreement constitutes the entire agreement
between the parties hereto concerning the subject matter hereof, and from and
after the date of this Agreement, this Agreement shall supersede any other prior
agreement or understanding, both written and oral, between the parties with
respect to such subject matter.

         (g) Captions. The captions herein are inserted for convenience of
reference only, do not constitute a part of this Agreement, and shall not affect
in any manner the meaning or interpretation of this Agreement.

         (h) References. All references in this Agreement to Paragraphs,
subparagraphs, and other subdivisions refer to the Paragraphs, subparagraphs,
and other subdivisions of this Agreement unless expressly provided otherwise.
The words "this Agreement", "herein", "hereof", "hereby", "hereunder", and words
of similar import refer to this Agreement as a whole and not to any particular
subdivision unless expressly so limited. Whenever the words "include",
"includes", and "including" are used in this Agreement, such words shall be
deemed to be followed by the words "without limitation". Words in the singular
form shall be construed to include the plural and vice versa, unless the context
otherwise requires.

                                       20

<PAGE>   24



         IN WITNESS WHEREOF, the Company has caused this Agreement to be
executed on its behalf by its duly authorized officer, and the Executive has
executed this Agreement, as of the date first above set forth.

                                    NOBLE DRILLING CORPORATION


                                    By: /S/ BYRON L. WELLIVER
                                       ----------------------------------------
                                        Name:   Byron L. Welliver
                                        Title:  Senior Vice President - Finance,
                                                Treasurer and Controller

                                                                       "COMPANY"



                                    /S/ JAMES C. DAY
                                    -------------------------------------------
                                    James C. Day

                                                                     "EXECUTIVE"



                                       21

<PAGE>   1
                                                                    EXHIBIT 10.2

================================================================================


                              EMPLOYMENT AGREEMENT



                                 BY AND BETWEEN



                           NOBLE DRILLING CORPORATION



                                       AND



                                BYRON L. WELLIVER





                                October 22, 1998



================================================================================

<PAGE>   2



                              EMPLOYMENT AGREEMENT
                                TABLE OF CONTENTS

<TABLE>
<CAPTION>
                                                                               Page
                                                                               ----
<S>                                                                              <C>
1.  Employment ............................................................      1

2.  Employment Term .......................................................      1
    (a) Term ..............................................................      1
    (b) Relationship Prior to Effective Date ..............................      1

3.  Positions and Duties ..................................................      2

4.  Compensation and Related Matters ......................................      3
    (a) Base Salary .......................................................      3
    (b) Annual Bonus ......................................................      3
    (c) Employee Benefits .................................................      4
        (i)  Incentive, Savings, and Retirement Plans .....................      4
        (ii) Welfare Benefit Plans ........................................      4
    (d) Expenses ..........................................................      4
    (e) Fringe Benefits ...................................................      4
    (f) Vacation ..........................................................      5

5.  Termination of Employment .............................................      5
    (a) Death .............................................................      5
    (b) Disability ........................................................      5
    (c) Termination by Company ............................................      5
    (d) Termination by Executive ..........................................      6
    (e) Notice of Termination .............................................      7
    (f) Date of Termination ...............................................      7

6.  Obligations of the Company Upon Termination ...........................      8
    (a) Good Reason or During the Window Period; Other Than for
        Cause, Death, or Disability .......................................      8
    (b) Death .............................................................     10
    (c) Disability ........................................................     11
    (d) Cause; Other Than for Good Reason or During the Window
        Period ............................................................     11

7.  Certain Additional Payments by the Company ............................     12

8.  Representations and Warranties ........................................     14

9.  Confidential Information ..............................................     14
</TABLE>


                                        i

<PAGE>   3

<TABLE>
<CAPTION>
                                                                               Page
                                                                               ----
<S>                                                                              <C>
10. Certain Definitions ...................................................     15
    (a) Effective Date ....................................................     15
    (b) Change of Control Period ..........................................     15
    (c) Change of Control .................................................     15

11. Full Settlement .......................................................     17

12. No Effect on Other Contractual Rights .................................     18

13. Indemnification; Directors and Officers Insurance .....................     18

14. Injunctive Relief .....................................................     18

15. Governing Law .........................................................     18

16. Notices ...............................................................     18

17. Binding Effect; Assignment; No Third Party Benefit ....................     19

18. Miscellaneous .........................................................     19
    (a) Amendment .........................................................     19
    (b) Waiver ............................................................     20
    (c) Withholding Taxes .................................................     20
    (d) Nonalienation of Benefits .........................................     20
    (e) Severability ......................................................     20
    (f) Entire Agreement ..................................................     20
    (g) Captions ..........................................................     20
    (h) References ........................................................     20
</TABLE>


                                       ii
<PAGE>   4

                              EMPLOYMENT AGREEMENT

         This EMPLOYMENT AGREEMENT (this "Agreement"), dated as of October 22,
1998, by and between NOBLE DRILLING CORPORATION, a Delaware corporation (the
"Company"), and BYRON L. WELLIVER (the "Executive");

                                   WITNESSETH:

         WHEREAS, the Board of Directors of the Company (the "Board") has
determined that it is in the best interests of the Company and its stockholders
to assure that the Company will have the continued dedication of the Executive,
notwithstanding the possibility, threat, or occurrence of a Change of Control
(as defined in Paragraph 10(c)) of the Company; and

         WHEREAS, the Board believes it is imperative to diminish the inevitable
distraction of the Executive by virtue of the personal uncertainties and risks
created by a pending or threatened Change of Control and to encourage the
Executive's full attention and dedication to the Company currently and in the
event of any pending or threatened Change of Control, and to provide the
Executive with compensation and benefits upon a Change of Control which ensure
that the compensation and benefits expectations of the Executive will be
satisfied and which are competitive with those of other corporations; and

         WHEREAS, in order to accomplish these objectives, the Board has caused
the Company to enter into this Agreement;

         NOW, THEREFORE, in consideration of the premises and the mutual
covenants and agreements herein contained, and intending to be legally bound
hereby, the Company and the Executive hereby agree as follows:

         1. Employment. The Company agrees that the Company or an affiliated
company (as hereafter defined) will continue the Executive in its employ, and
the Executive agrees to remain in the employ of the Company or an affiliated
company, for the period set forth in Paragraph 2(a), in the positions and with
the duties and responsibilities set forth in Paragraph 3, and upon the other
terms and conditions herein provided. As used in this Agreement, the term
"affiliated company" shall include any company controlled by, controlling, or
under common control with the Company.

         2. Employment Term.

         (a) Term. The employment of the Executive by the Company as provided in
Paragraph 1 shall be for the period commencing on the Effective Date (as defined
in Paragraph 10 (a)) through and ending on the third anniversary of such date
(the "Employment Term").

         (b) Relationship Prior to Effective Date. The Executive and the Company
acknowledge that, except as may otherwise be provided under any written
agreement between the Executive and the Company other than this Agreement, the
employment of the Executive by the

                                        1

<PAGE>   5



Company is "at will" and, prior to the Effective Date, may be terminated by
either the Executive or the Company at any time. Moreover, if prior to the
Effective Date, the Executive's employment with the Company terminates, then the
Executive shall have no further rights under this Agreement. For purposes of
this Paragraph 2(b) only, the term Company shall mean and include the company
that employs Executive, whether Noble Drilling Corporation or an affiliated
company of Noble Drilling Corporation.

         3. Positions and Duties.

         (a) During the Employment Term, the Executive's position (including
status, offices, titles, and reporting requirements), duties, functions,
responsibilities, and authority shall be at least commensurate in all material
respects with the most significant of those held or exercised by or assigned to
the Executive in respect of the Company and its affiliated companies at any time
during the 120-day period immediately preceding the Effective Date.

         (b) During the Employment Term, the Executive shall devote the
Executive's full time, skill, and attention and the Executive's reasonable best
efforts during normal business hours to the business and affairs of the Company,
and in furtherance of the business and affairs of its affiliated companies, to
the extent necessary to discharge faithfully and efficiently the duties and
responsibilities delegated and assigned to the Executive herein or pursuant
hereto, except for usual, ordinary, and customary periods of vacation and
absence due to illness or other disability; provided, however, that the
Executive may (i) serve on industry-related, civic or charitable boards or
committees, (ii) with the approval of the Board, serve on corporate boards or
committees, (iii) deliver lectures, fulfill speaking engagements, or teach at
educational institutions, and (iv) manage the Executive's personal investments,
so long as such activities do not significantly interfere with the performance
and fulfillment of the Executive's duties and responsibilities as an employee of
the Company or an affiliated company in accordance with this Agreement and, in
the case of the activities described in clause (ii) of this proviso, will not,
in the good faith judgment of the Board, constitute an actual or potential
conflict of interest with the business of the Company or an affiliated company.
It is expressly understood and agreed that, to the extent that any such
activities have been conducted by the Executive during the term of the
Executive's employment by the Company or its affiliated companies prior to the
Effective Date consistent with the provisions of this Paragraph 3(b), the
continued conduct of such activities (or of activities similar in nature and
scope thereto) subsequent to the Effective Date shall not thereafter be deemed
to interfere with the performance and fulfillment of the Executive's duties and
responsibilities to the Company.

         (c) In connection with the Executive's employment hereunder, the
Executive shall be based at the location where the Executive was regularly
employed immediately prior to the Effective Date or any office which is the
headquarters of the Company and is less than 50 miles from such location,
subject, however, to required travel on the business of the Company to an extent
substantially consistent with the Executive's business travel obligations during
the three-year period immediately preceding the Effective Date.


                                        2

<PAGE>   6



         (d) All services that the Executive may render to the Company or any of
its affiliated companies in any capacity during the Employment Term shall be
deemed to be services required by this Agreement and consideration for the
compensation provided for herein.

         4. Compensation and Related Matters.

         (a) Base Salary. During the Employment Term, the Executive shall
receive an annual base salary ("Base Salary") at least equal to 12 times the
highest monthly base salary paid or payable, including any base salary that has
been earned but deferred, to the Executive by the Company and its affiliated
companies in respect of the 12-month period immediately preceding the month in
which the Effective Date occurs. The Base Salary shall be payable in
installments in accordance with the general payroll practices of the Company in
effect at the time such payment is made, but in no event less frequently than
monthly, or as otherwise mutually agreed upon. During the Employment Term, the
Executive's Base Salary shall be subject to such increases (but not decreases)
as may be determined from time to time by the Board in its sole discretion;
provided, however, that the Executive's Base Salary (i) shall be reviewed by the
Board no later than 12 months after the last salary increase awarded to the
Executive prior to the Effective Date and thereafter at least annually, with a
view to making such upward adjustment, if any, as the Board deems appropriate,
and (ii) shall be increased at any time and from time to time as shall be
substantially consistent with increases in base salary generally awarded in the
ordinary course of business to the Executive's peer executives of the Company or
any of its affiliated companies. Base Salary shall not be reduced after any such
increase. The term Base Salary as used in this Agreement shall refer to the Base
Salary as so increased. Payments of Base Salary to the Executive shall not be
deemed exclusive and shall not prevent the Executive from participating in any
employee benefit plans, programs, or arrangements of the Company and its
affiliated companies in which the Executive is entitled to participate. Payments
of Base Salary to the Executive shall not in any way limit or reduce any other
obligation of the Company hereunder, and no other compensation, benefit, or
payment to the Executive hereunder shall in any way limit or reduce the
obligation of the Company regarding the Executive's Base Salary hereunder.

         (b) Annual Bonus. In addition to Base Salary, the Executive shall be
awarded, in respect of each fiscal year of the Company ending during the
Employment Term, an annual bonus (the "Annual Bonus") in cash in an amount at
least equal to the Executive's highest aggregate bonus under all Company bonus
plans, programs, arrangements, and awards (including the Company's Short-Term
Incentive Plan and any successor plan), in respect of any fiscal year in the
three full fiscal year period ended immediately prior to the Effective Date
(annualized for any fiscal year consisting of less than 12 full months or with
respect to which the Executive has been employed by the Company for less than 12
full months) (such highest amount is hereinafter referred to as the "Recent
Annual Bonus"). Each such Annual Bonus shall be paid no later than the end of
the third month of the fiscal year next following the fiscal year in respect of
which the Annual Bonus is awarded, unless the Executive shall elect to defer the
receipt of such Annual Bonus.


                                        3

<PAGE>   7



         (c) Employee Benefits.

                      (i) Incentive, Savings, and Retirement Plans. During the
         Employment Term, the Executive shall be entitled to participate in all
         incentive, savings, and retirement plans, programs, and arrangements
         applicable generally to the Executive's peer executives of the Company
         and its affiliated companies, but in no event shall such plans,
         programs, and arrangements provide the Executive with incentive
         opportunities (measured with respect to both regular and special
         incentive opportunities, to the extent, if any, that such distinction
         is applicable), savings opportunities, and retirement benefit
         opportunities, in each case, less favorable, in the aggregate, than the
         most favorable of those provided by the Company and its affiliated
         companies for the Executive under such plans, programs, and
         arrangements as in effect at any time during the 120-day period
         immediately preceding the Effective Date or, if more favorable to the
         Executive, those provided generally at any time after the Effective
         Date to the Executive's peer executives of the Company and its
         affiliated companies.

                      (ii) Welfare Benefit Plans. During the Employment Term,
         the Executive and/or the Executive's family, as the case may be, shall
         be eligible to participate in and shall receive all benefits under all
         welfare benefit plans, programs, and arrangements provided by the
         Company and its affiliated companies (including, without limitation,
         medical, prescription, dental, disability, salary continuance, employee
         life, group life, accidental death, and travel accident insurance
         plans, programs, and arrangements) to the extent applicable generally
         to the Executive's peer executives of the Company and its affiliated
         companies, but in no event shall such plans, programs, and arrangements
         provide the Executive with welfare benefits that are less favorable, in
         the aggregate, than the most favorable of such plans, programs, and
         arrangements as in effect for the Executive at any time during the
         120-day period immediately preceding the Effective Date or, if more
         favorable to the Executive, those provided generally at any time after
         the Effective Date to the Executive's peer executives of the Company
         and its affiliated companies.

         (d) Expenses. During the Employment Term, the Executive shall be
entitled to receive prompt reimbursement for all reasonable expenses incurred by
the Executive in performing the Executive's duties and responsibilities
hereunder, in accordance with the most favorable policies, practices, and
procedures of the Company and its affiliated companies as in effect for the
Executive at any time during the 120-day period immediately preceding the
Effective Date or, if more favorable to the Executive, as in effect generally at
any time thereafter with respect to the Executive's peer executives of the
Company and its affiliated companies.

         (e) Fringe Benefits. During the Employment Term, the Executive shall be
entitled to fringe benefits, including, without limitation, tax and financial
planning services, payment of club dues, and, if applicable, use of an
automobile and payment of related expenses, in accordance with the most
favorable policies, practices, and procedures of the Company and its affiliated
companies as in effect for the Executive at any time during the 120-day period
immediately preceding the Effective Date or, if more favorable to the Executive,
as in effect generally at any

                                        4

<PAGE>   8



time after the Effective Date with respect to the Executive's peer executives of
the Company and its affiliated companies.

         (f) Vacation. During the Employment Term, the Executive shall be
entitled to paid vacation and such other paid absences, whether for holidays,
illness, personal time, or any similar purposes, in accordance with the most
favorable policies, practices, and procedures of the Company and its affiliated
companies as in effect for the Executive at any time during the 120-day period
immediately preceding the Effective Date or, if more favorable to the Executive,
as in effect generally at any time after the Effective Date with respect to the
Executive's peer executives of the Company and its affiliated companies.

         5. Termination of Employment.

         (a) Death. The Executive's employment shall terminate automatically
upon the Executive's death during the Employment Term.

         (b) Disability. If the Company determines in good faith that the
Disability (as defined below) of the Executive has occurred during the
Employment Term, the Company may give the Executive notice of its intention to
terminate the Executive's employment. In such event, the Executive's employment
hereunder shall terminate effective on the 30th day after receipt of such notice
by the Executive (the "Disability Effective Date"), provided that, within the
30-day period after such receipt, the Executive shall not have returned to
full-time performance of the Executive's duties. For purposes of this Agreement,
"Disability" shall mean the absence of the Executive from the Executive's duties
hereunder on a full-time basis for an aggregate of 180 days within any given
period of 270 consecutive days (in addition to any statutorily required leave of
absence and any leave of absence approved by the Company), as a result of
incapacity of the Executive, despite any reasonable accommodation required by
law, due to bodily injury or disease or any other mental or physical illness,
which will, in the opinion of a physician selected by the Company or its
insurers and acceptable to the Executive or the Executive's legal
representative, be permanent and continuous during the remainder of the
Executive's life.

         (c) Termination by Company. The Company may terminate the Executive's
employment hereunder for Cause (as defined below). For purposes of this
Agreement, "Cause" shall mean:

                      (i) the willful and continued failure of the Executive to
         perform substantially the Executive's duties hereunder (other than any
         such failure resulting from bodily injury or disease or any other
         incapacity due to mental or physical illness), after a written demand
         for substantial performance is delivered to the Executive by the Board
         or the Chief Executive Officer of the Company which specifically
         identifies the manner in which the Board or Chief Executive Officer
         believes the Executive has not substantially performed the Executive's
         duties; or


                                        5

<PAGE>   9



                      (ii) the willful engaging by the Executive in illegal
         conduct or gross misconduct that is materially and demonstrably
         detrimental to the Company, monetarily or otherwise.

For purposes of this provision, no act, or failure to act, on the part of the
Executive shall be considered "willful" unless done, or omitted to be done, by
the Executive in bad faith or without reasonable belief that the Executive's
action or omission was in the best interests of the Company. Any act, or failure
to act, based upon authority given pursuant to a resolution duly adopted by the
Board or upon the instructions of the Chief Executive Officer or another senior
officer of the Company or based upon the advice of counsel for the Company shall
be conclusively presumed to be done, or omitted to be done, by the Executive in
good faith and in the best interests of the Company. The cessation of employment
of the Executive shall not be deemed to be for Cause unless and until there
shall have been delivered to the Executive a copy of a resolution duly adopted
by the affirmative vote of not less than two-thirds of the entire membership of
the Board then in office at a meeting of the Board called and held for such
purpose (after reasonable notice is provided to the Executive and the Executive
is given an opportunity, together with counsel, to be heard before the Board)
finding that, in the good faith opinion of the Board, the Executive is guilty of
the conduct described in subparagraph (i) or (ii) above, and specifying the
particulars thereof in detail.

         (d) Termination by Executive. The Executive may terminate the
Executive's employment hereunder (i) at any time during the Employment Term for
Good Reason (as defined below) or (ii) during the Window Period (as defined
below) without any reason.

For purposes of this Agreement, the "Window Period" shall mean the 30-day period
immediately following the first anniversary of the Effective Date, and "Good
Reason" shall mean any of the following (without the Executive's express written
consent):

                      (i) the assignment to the Executive of any duties
         inconsistent in any respect with the Executive's position (including
         status, offices, titles, and reporting requirements), duties,
         functions, responsibilities, or authority as contemplated by Paragraph
         3(a) of this Agreement, or any other action by the Company that results
         in a diminution in such position, duties, functions, responsibilities,
         or authority, excluding for this purpose an isolated, insubstantial,
         and inadvertent action not taken in bad faith and which is remedied by
         the Company promptly after receipt of notice thereof given by the
         Executive;

                      (ii) any failure by the Company to comply with any of the
         provisions of Paragraph 4 of this Agreement, other than an isolated,
         insubstantial, and inadvertent action not taken in bad faith and which
         is remedied by the Company promptly after receipt of notice thereof
         given by the Executive;

                      (iii) the Company's requiring the Executive to be based at
         any office or location other than as provided in Paragraph 3(c) of this
         Agreement or the Company's



                                        6

<PAGE>   10



         requiring the Executive to travel on Company business to a
         substantially greater extent than during the three-year period
         immediately preceding the Effective Date;

                      (iv) any failure by the Company to comply with and satisfy
         Paragraph 17(c) of this Agreement; or

                      (v) any purported termination by the Company of the
         Executive's employment hereunder otherwise than as expressly permitted
         by this Agreement, and for purposes of this Agreement, no such
         purported termination shall be effective.

For purposes of this Paragraph 5(d), any good faith determination of "Good
Reason" made by the Executive shall be conclusive.

         (e) Notice of Termination. Any termination of the Executive's
employment hereunder by the Company or by the Executive (other than a
termination pursuant to Paragraph 5(a)) shall be communicated by a Notice of
Termination (as defined below) to the other party hereto. For purposes of this
Agreement, a "Notice of Termination" shall mean a notice which (i) indicates the
specific termination provision in this Agreement relied upon, (ii) in the case
of a termination for Disability, Cause, or Good Reason, sets forth in reasonable
detail the facts and circumstances claimed to provide a basis for termination of
the Executive's employment under the provision so indicated, and (iii) specifies
the Date of Termination (as defined in Paragraph 5(f) below); provided, however,
that, notwithstanding any provision in this Agreement to the contrary, a Notice
of Termination given in connection with a termination for Good Reason shall be
given by the Executive within a reasonable period of time, not to exceed 120
days, following the occurrence of the event giving rise to such right of
termination. The failure by the Company or the Executive to set forth in the
Notice of Termination any fact or circumstance which contributes to a showing of
Disability, Cause, or Good Reason shall not waive any right of the Company or
the Executive hereunder or preclude the Company or the Executive from asserting
such fact or circumstance in enforcing the Company's or the Executive's rights
hereunder.

         (f) Date of Termination. For purposes of this Agreement, the "Date of
Termination" shall mean the effective date of termination of the Executive's
employment hereunder, which date shall be (i) if the Executive's employment is
terminated by the Executive's death, the date of the Executive's death, (ii) if
the Executive's employment is terminated because of the Executive's Disability,
the Disability Effective Date, (iii) if the Executive's employment is terminated
by the Company for Cause or by the Executive for Good Reason, the date on which
the Notice of Termination is given, (iv) if the Executive's employment is
terminated pursuant to Paragraph 2(a), the date on which the Employment Term
ends pursuant to Paragraph 2(a) due to a party's delivery of a Notice of
Termination thereunder, and (v) if the Executive's employment is terminated for
any other reason, the date specified in the Notice of Termination, which date
shall in no event be earlier than the date such notice is given; provided,
however, that if within 30 days after any Notice of Termination is given, the
party receiving such Notice of Termination notifies the other party that a
dispute exists concerning the termination, the Date of Termination shall be the
date on which the dispute is finally determined, either by mutual written
agreement

                                        7

<PAGE>   11



of the parties or by a final judgment, order, or decree of a court of competent
jurisdiction (the time for appeal therefrom having expired and no appeal having
been perfected).

         6. Obligations of the Company Upon Termination.

         (a) Good Reason or During the Window Period; Other Than for Cause,
Death, or Disability. If, during the Employment Term, the Company shall
terminate the Executive's employment hereunder other than for Cause or
Disability or the Executive shall terminate the Executive's employment either
for Good Reason or without any reason during the Window Period:

                      (i) the Company shall pay to the Executive in a lump sum
         in cash within 30 days after the Date of Termination the aggregate of
         the following amounts:

                                  (A) the sum of (1) the Executive's Base Salary
                      through the Date of Termination to the extent not
                      theretofore paid, (2) the product of (x) the greater of
                      (I) the Recent Annual Bonus and (II) the Annual Bonus paid
                      or payable, including by reason of any deferral, to the
                      Executive (and annualized for any fiscal year consisting
                      of less than 12 full months or for which the Executive has
                      been employed by the Company for less than 12 full months)
                      in respect of the most recently completed fiscal year of
                      the Company during the Employment Term, if any (such
                      greater amount hereinafter referred to as the "Highest
                      Annual Bonus"), and (y) a fraction, the numerator of which
                      is the number of days in the current fiscal year through
                      the Date of Termination, and the denominator of which is
                      365, and (3) any compensation previously deferred by the
                      Executive (together with any accrued interest or earnings
                      thereon) and any accrued vacation pay, in each case to the
                      extent not theretofore paid (the sum of the amounts
                      described in clauses (1), (2), and (3) are hereinafter
                      referred to as the "Accrued Obligations"); and

                                  (B) an amount (such amount is hereinafter
                      referred to as the "Severance Amount") equal to the
                      product of (1) three and (2) the sum of (x) the
                      Executive's Base Salary and (y) the Highest Annual Bonus;
                      and

                                  (C) a separate lump-sum supplemental
                      retirement benefit (the amount of such benefit hereinafter
                      referred to as the "Supplemental Retirement Amount") equal
                      to the difference between (1) the actuarial equivalent
                      (utilizing for this purpose the actuarial assumptions
                      utilized with respect to the qualified defined benefit
                      retirement plan of the Company and its affiliated
                      companies in which the Executive is eligible to
                      participate (or any successor plan thereto) (the
                      "Retirement Plan") during the 120-day period immediately
                      preceding the Effective Date) of the benefit payable under
                      the Retirement Plan and any supplemental and/or excess
                      retirement plan of the Company and its affiliated
                      companies providing benefits for the Executive (the
                      "SERP") which the Executive would receive if the
                      Executive's employment continued at the compensation level
                      provided for in Paragraphs 4(a) and 4(b)(i) for the
                      remainder

                                        8

<PAGE>   12



                      of the Employment Term, assuming for this purpose that all
                      accrued benefits are fully vested and that benefit accrual
                      formulas are no less advantageous to the Executive than
                      those in effect during the 120-day period immediately
                      preceding the Effective Date, and (2) the actuarial
                      equivalent (utilizing for this purpose the actuarial
                      assumptions utilized with respect to the Retirement Plan
                      during the 120-day period immediately preceding the
                      Effective Date) of the Executive's actual benefit (paid or
                      payable), if any, under the Retirement Plan and the SERP;
                      and

                      (ii) for three years after the Executives's Date of
         Termination, or such longer period as any plan, program, or arrangement
         may provide, the Company shall continue benefits to the Executive
         and/or the Executive's family at least equal to those that would have
         been provided to them in accordance with the plans, programs, and
         arrangements described in Paragraph 4(c)(ii) if the Executive's
         employment had not been terminated, in accordance with the most
         favorable plans, programs, and arrangements of the Company as in effect
         and applicable generally to the Executive's peer executives of the
         Company and its affiliated companies and their families during the
         120-day period immediately preceding the Effective Date or, if more
         favorable to the Executive, as in effect generally at any time
         thereafter with respect to the Executive's peer executives of the
         Company and its affiliated companies and their families; provided,
         however, that if the Executive becomes reemployed with another employer
         and is eligible to receive medical or other welfare benefits under
         another employer provided plan, the medical and other welfare benefits
         described herein shall be secondary to those provided under such other
         plan during such applicable period of eligibility (such continuation of
         such benefits for the applicable period herein set forth is hereinafter
         referred to as "Welfare Benefit Continuation") (for purpose of
         determining eligibility of the Executive for retiree benefits pursuant
         to such plans, programs, and arrangements, the Executive shall be
         considered to have remained employed until three years after the Date
         of Termination and to have retired on the last day of such period); and

                      (iii) the Company shall, at its sole expense as incurred,
         provide the Executive with outplacement services the scope and provider
         of which shall be selected by the Executive in the Executive's sole
         discretion; and

                      (iv) with respect to all options to purchase Common Stock
         held by the Executive pursuant to a Company stock option plan on or
         prior to the Date of Termination, irrespective of whether such options
         are then exercisable, the Executive shall have the right, during the
         60-day period after the Date of Termination, to elect to surrender all
         or part of such options in exchange for a cash payment by the Company
         to the Executive in an amount equal to the number of shares of Common
         Stock subject to the Executive's option multiplied by the excess of (x)
         over (y), where (x) equals the highest reported sale price of a share
         of Common Stock in any transaction reported on the New York Stock
         Exchange during the 60-day period prior to and including the
         Executive's Date of Termination and (y) equals the purchase price per
         share covered by the option. Such cash payments shall be made within 30
         days after the date of the Executive's election; provided,

                                        9

<PAGE>   13



         however, that if the Executive's Date of Termination is within six
         months after the date of grant of a particular option held by the
         Executive and the Executive is subject to Section 16(b) of the
         Securities Exchange Act of 1934, as amended (the "Exchange Act"), any
         cash payments related thereto shall be made on the date which is six
         months and one day after the date of grant of such option to the extent
         necessary to prevent the imposition of the disgorgement provisions
         under Section 16(b). Notwithstanding the foregoing, if any right
         granted pursuant to the foregoing would make any change of control
         transaction ineligible for pooling of interests accounting treatment
         under APB No. 16 that but for this Section 6(a)(iv) would otherwise be
         eligible for such accounting treatment, the Executive shall receive
         shares of Common Stock with a fair market value equal to the cash that
         would otherwise be payable hereunder in substitution for the cash,
         provided that any such shares of Common Stock so delivered to the
         Executive shall be registered under the Securities Act of 1933, as
         amended; any options outstanding as of the Date of Termination and not
         then exercisable shall become fully exercisable as of the Executive's
         Date of Termination, and to the extent the Executive does not elect to
         surrender same for a cash payment (or the equivalent number of shares
         of Common Stock) as provided above, such options shall remain
         exercisable after the Executive's Date of Termination in accordance
         with the terms thereof; and restrictions applicable to any shares of
         Common Stock awarded to the Executive by the Company shall lapse, as of
         the date of the Executive's Date of Termination; and

                      (v) all club memberships and other memberships that the
         Company was providing for the Executive's use at the time Notice of
         Termination is given shall, to the extent possible, be transferred and
         assigned to the Executive at no cost to the Executive (other than
         income taxes owed), the cost of transfer, if any, to be borne by the
         Company; and

                      (vi) all benefits under the Noble Drilling Corporation
         1991 Stock Option and Restricted Stock Plan and any other similar
         plans, including any stock options or restricted stock held by the
         Executive, not already vested shall be 100% vested, to the extent such
         vesting is permitted under the Code; and

                      (vii) to the extent not theretofore paid or provided, the
         Company shall timely pay or provide to the Executive any other amounts
         or benefits required to be paid or provided or which the Executive is
         eligible to receive under any plan, program, policy, practice, or
         arrangement or contract or agreement of the Company and its affiliated
         companies (such other amounts and benefits hereinafter referred to as
         the "Other Benefits").

         (b) Death. If the Executive's employment is terminated by reason of the
Executive's death during the Employment Term, this Agreement shall terminate
without further obligations to the Executive's legal representatives under this
Agreement, other than for (i) payment of Accrued Obligations (which shall be
paid to the Executive's estate or beneficiary, as applicable, in a lump sum in
cash within 30 days of the Date of Termination) and the timely payment or
provision of the Welfare Benefit Continuation and the Other Benefits and (ii)
payment to the

                                       10

<PAGE>   14



Executive's estate or beneficiaries, as applicable, in a lump sum in cash within
30 days of the Date of Termination of an amount equal to the sum of the
Severance Amount and the Supplemental Retirement Amount. With respect to the
provision of Other Benefits, the term Other Benefits as used in this Section
6(b) shall include, without limitation, and the Executive's estate and/or
beneficiaries shall be entitled to receive, benefits at least equal to the most
favorable benefits provided by the Company and affiliated companies to the
estates and beneficiaries of peer executives of the Company and such affiliated
companies under such plans, programs, practices, and policies relating to death
benefits, if any, as in effect with respect to other peer executives and their
beneficiaries at any time during the 120-day period immediately preceding the
Effective Date or, if more favorable to the Executive's estate and/or the
Executive's beneficiaries, as in effect on the date of the Executive's death
with respect to other peer executives of the Company and its affiliated
companies and their beneficiaries.

         (c) Disability. If the Executive's employment is terminated by reason
of the Executive's Disability during the Employment Term, this Agreement shall
terminate without further obligations to the Executive, other than for (i)
payment of Accrued Obligations (which shall be paid to the Executive in a lump
sum in cash within 30 days of the Date of Termination) and the timely payment or
provision of the Welfare Benefit Continuation and the Other Benefits and (ii)
payment to the Executive in a lump sum in cash within 30 days of the Date of
Termination of an amount equal to the sum of the Severance Amount and the
Supplemental Retirement Amount. With respect to the provision of Other Benefits,
the term Other Benefits as used in this Section 6(c) shall include, without
limitation, and the Executive shall be entitled after the Disability Effective
Date to receive, disability and other benefits at least equal to the most
favorable of those generally provided by the Company and affiliated companies to
disabled executives and/or their families in accordance with such plans,
programs, practices, and policies relating to disability, if any, as in effect
generally with respect to other peer executives and their families at any time
during the 120-day period immediately preceding the Effective Date or, if more
favorable to the Executive and/or the Executive's family, as in effect at any
time thereafter generally with respect to other peer executives of the Company
and its affiliated companies and their families.

         (d) Cause; Other Than for Good Reason or During the Window Period. If
the Executive's employment is terminated for Cause during the Employment Term,
this Agreement shall terminate without further obligations to the Executive
other than the obligation to pay to the Executive Base Salary through the Date
of Termination plus the amount of any compensation previously deferred by the
Executive, in each case to the extent theretofore unpaid. If the Executive
voluntarily terminates the Executive's employment during the Employment Term,
excluding a termination either for Good Reason or without any reason during the
Window Period, this Agreement shall terminate without further obligations to the
Executive, other than for Accrued Obligations and the timely payment or
provision of the Other Benefits. In such case, all Accrued Obligations shall be
paid to the Executive in a lump sum in cash within 30 days of the Date of
Termination subject to applicable laws and regulations.


                                       11

<PAGE>   15



         7. Certain Additional Payments by the Company.

         (a) Notwithstanding any provision in this Agreement to the contrary and
except as set forth below, if it shall be determined that any payment or
distribution by the Company to or for the benefit of the Executive (whether paid
or payable or distributed or distributable pursuant to the terms of this
Agreement or otherwise, but determined without regard to any additional payments
required pursuant to this Paragraph 7) (a "Payment") would be subject to the
excise tax imposed by Section 4999 of the Code or any interest or penalties are
incurred by the Executive with respect to such excise tax (such excise tax,
together with any such interest and penalties, are hereinafter collectively
referred to as the "Excise Tax"), then the Executive shall be entitled to
receive an additional payment (a "Gross-Up Payment") in an amount such that
after payment by the Executive of all taxes (including any interest or penalties
imposed with respect to such taxes), including any income taxes (and any
interest and penalties imposed with respect thereto) and Excise Tax imposed upon
the Gross-Up Payment, the Executive retains an amount of the Gross- Up Payment
equal to the Excise Tax imposed upon the Payments. Notwithstanding the foregoing
provisions of this Paragraph 7(a), if it shall be determined that the Executive
is entitled to a Gross-Up Payment, but that the Executive, after taking into
account the Payments and the Gross-Up Payment, would not receive a net after-tax
benefit of at least $50,000 (taking into account both income taxes and any
Excise Tax) as compared to the net after-tax proceeds to the Executive resulting
from an elimination of the Gross-Up Payment and a reduction of the Payments, in
the aggregate, to an amount (the "Reduced Amount") such that the receipt of
payments would not give rise to any Excise Tax, then no Gross-Up Payment shall
be made to the Executive and the Payments, in the aggregate, shall be reduced to
the Reduced Amount.

         (b) Subject to the provisions of Paragraph 7(c), all determinations
required to be made under this Paragraph 7, including whether and when a
Gross-Up Payment is required and the amount of such Gross-Up Payment and the
assumptions to be utilized in arriving at such determination, shall be made by
PricewaterhouseCoopers (the "Accounting Firm") or, as provided below, such other
certified public accounting firm as may be designated by the Executive, which
shall provide detailed supporting calculations both to the Company and the
Executive within 15 business days after the receipt of notice from the Executive
that there has been a Payment, or such earlier time as is requested by the
Company. If the Accounting Firm is serving as accountant or auditor for the
individual, entity, or group effecting the Change of Control, the Executive
shall have the option, in the Executive's sole discretion, to appoint another
nationally recognized accounting firm to make the determinations required
hereunder (which accounting firm shall then be referred to as the Accounting
Firm hereunder). All fees and expenses of the Accounting Firm shall be borne
solely by the Company. Any Gross-Up Payment, as determined pursuant to this
Paragraph 7, shall be paid by the Company to the Executive within five days of
the receipt of the Accounting Firm's determination. If the Accounting Firm
determines that no Excise Tax is payable by the Executive, it shall furnish the
Executive with a written opinion that failure to report the Excise Tax on the
Executive's applicable federal income tax return would not result in the
imposition of a negligence or similar penalty. Any determination by the
Accounting Firm shall be binding upon the Company and the Executive. As a result
of the uncertainty in the application of Section 4999 of the Code at the time of
the initial determination by the Accounting Firm hereunder, it is possible that
Gross-Up Payments that will not have been made by the Company

                                       12

<PAGE>   16



should have been made ("Underpayment"), consistent with the calculations
required to be made hereunder. If the Company exhausts its remedies pursuant to
Paragraph 7(c) and the Executive thereafter is required to make a payment of any
Excise Tax, the Accounting Firm shall determine the amount of the Underpayment
that has occurred and any such Underpayment shall be promptly paid by the
Company to or for the benefit of the Executive.

         (c) The Executive shall notify the Company in writing of any claim by
the Internal Revenue Service that, if successful, would require the payment by
the Company of the Gross-Up Payment (or an additional amount of Gross-Up
Payment) in the event the Internal Revenue Service seeks higher payment. Such
notification shall be given as soon as practicable but no later than 10 business
days after the Executive is informed in writing of such claim and shall apprise
the Company of the nature of such claim and the date on which such claim is
requested to be paid. The Executive shall not pay such claim prior to the
expiration of the 30-day period following the date on which it gives such notice
to the Company (or such shorter period ending on the date that any payment of
taxes with respect to such claim is due). If the Company notifies the Executive
in writing prior to the expiration of such period that it desires to contest
such claim, the Executive shall:

                      (i) give the Company any information reasonably requested
         by the Company relating to such claim;

                      (ii) take such action in connection with contesting such
         claim as the Company shall reasonably request in writing from time to
         time, including the acceptance of legal representation with respect to
         such claim by an attorney reasonably selected by the Company;

                      (iii) cooperate with the Company in good faith in order
         effectively to contest such claim; and

                      (iv) permit the Company to participate in any proceedings
         relating to such claim;

provided, however, that the Company shall bear and pay directly all costs and
expenses (including additional interest and penalties) incurred in connection
with such contest and shall indemnify and hold the Executive harmless, on an
after-tax basis, for any Excise Tax or income tax (including interest and
penalties with respect thereto) imposed as a result of such representation and
payment of costs and expenses. Without limitation of the foregoing provisions of
this Paragraph 7(c), the Company shall control all proceedings taken in
connection with such contest and, at its sole option, may pursue or forgo any
and all administrative appeals, proceedings, hearings, and conferences with the
taxing authority in respect of such claim and may, at its sole option, either
direct the Executive to pay the tax claimed and sue for a refund or contest the
claim in any permissible manner, and the Executive agrees to prosecute such
contest to a determination before any administrative tribunal, in a court of
initial jurisdiction, and in one or more appellate courts, as the Company shall
determine; provided, however, that if the Company directs the Executive to pay
such claim and sue for a refund, the Company shall advance the amount of such
payment to

                                       13

<PAGE>   17



the Executive, on an interest-free basis, and shall indemnify and hold the
Executive harmless, on an after-tax basis, from any Excise Tax or income tax
(including interest or penalties with respect thereto) imposed with respect to
such advance or with respect to any imputed income with respect to such advance;
and provided further that any extension of the statute of limitations relating
to payment of taxes for the taxable year of the Executive with respect to which
such contested amount is claimed to be due is limited solely to such contested
amount. Furthermore, the Company's control of the contest shall be limited to
issues with respect to which a Gross-Up Payment would be payable hereunder and
the Executive shall be entitled to settle or contest, as the case may be, any
other issue raised by the Internal Revenue Service or any other taxing
authority.

         (d) If, after the receipt by the Executive of an amount advanced by the
Company pursuant to Paragraph 7(c), the Executive becomes entitled to receive
any refund with respect to such claim, the Executive shall (subject to the
Company's complying with the requirements of Paragraph 7(c)) promptly pay to the
Company the amount of such refund (together with any interest paid or credited
thereon after taxes applicable thereto). If, after the receipt by the Executive
of an amount advanced by the Company pursuant to Paragraph 7(c), a determination
is made that the Executive shall not be entitled to any refund with respect to
such claim and the Company does not notify the Executive in writing of its
intent to contest such denial of refund prior to the expiration of 30 days after
such determination, then such advance shall be forgiven and shall not be
required to be repaid and the amount of such advance shall offset, to the extent
thereof, the amount of Gross-Up Payment required to be paid.

         8. Representations and Warranties.

         (a) The Company represents and warrants to the Executive that the
execution, delivery, and performance by the Company of this Agreement have been
duly authorized by all necessary corporate action of the Company and do not and
will not conflict with or result in a violation of any provision of, or
constitute a default under, any contract, agreement, instrument, or obligation
to which the Company is a party or by which it is bound.

         (b) The Executive represents and warrants to the Company that the
execution, delivery, and performance by the Executive of this Agreement do not
and will not conflict with or result in a violation of any provision of, or
constitute a default under, any contract, agreement, instrument, or obligation
to which the Executive is a party or by which the Executive is bound.

         9. Confidential Information. The Executive recognizes and acknowledges
that the Company's trade secrets and other confidential or proprietary
information, as they may exist from time to time, are valuable, special, and
unique assets of the Company's business, access to and knowledge of which are
essential to the performance of the Executive's duties hereunder. The Executive
confirms that all such trade secrets and other information constitute the
exclusive property of the Company. During the Employment Term and thereafter
without limitation of time, the Executive shall hold in strict confidence and
shall not, directly or indirectly, disclose or reveal to any person, or use for
the Executive's own personal benefit or for the benefit of anyone else, any
trade secrets, confidential dealings, or other confidential or proprietary
information of any kind, nature, or description (whether or not acquired,
learned, obtained, or developed by the

                                       14

<PAGE>   18



Executive alone or in conjunction with others) belonging to or concerning the
Company or any of its affiliated companies, except (i) with the prior written
consent of the Company duly authorized by its Board, (ii) in the course of the
proper performance of the Executive's duties hereunder, (iii) for information
(x) that becomes generally available to the public other than as a result of
unauthorized disclosure by the Executive or the Executive's affiliates or (y)
that becomes available to the Executive on a nonconfidential basis from a source
other than the Company or its affiliated companies who is not bound by a duty of
confidentiality, or other contractual, legal, or fiduciary obligation, to the
Company, or (iv) as required by applicable law or legal process. The provisions
of this Paragraph 9 shall continue in effect notwithstanding termination of the
Executive's employment hereunder for any reason.

         10. Certain Definitions.

         (a) Effective Date. The "Effective Date" shall mean the first date
during the Change of Control Period (as defined in Paragraph 10(b)) on which a
Change of Control occurs. Notwithstanding anything in this Agreement to the
contrary, if a Change of Control occurs and if the Executive's employment with
the Company is terminated prior to the date on which the Change of Control
occurs, and if it is reasonably demonstrated by the Executive that such
termination of employment (i) was at the request of a third party who has taken
steps reasonably calculated to effect a Change of Control or (ii) otherwise
arose in connection with or anticipation of a Change of Control, then for all
purposes of this Agreement the "Effective Date" shall mean the date immediately
prior to the date of such termination of employment.

         (b) Change of Control Period. The "Change of Control Period" shall mean
the period commencing on the date of this Agreement and ending on the third
anniversary of such date; provided, however, that commencing on the date one
year after the date hereof, and on each annual anniversary of such date (such
date and each annual anniversary thereof herein referred to as the "Renewal
Date"), the Change of Control Period shall be automatically extended so as to
terminate three years after such Renewal Date, unless at least 60 days prior to
the Renewal Date the Company shall give notice to the Executive that the Change
of Control Period shall not be so extended.

         (c) Change of Control. For purposes of this Agreement, a "Change of
Control" shall mean:

                      (i) the acquisition by any individual, entity, or group
         (within the meaning of Section 13(d)(3) or 14(d)(2) of the Exchange
         Act) (a "Person") of beneficial ownership (within the meaning of Rule
         13d-3 promulgated under the Exchange Act) of 15% or more of either (A)
         the then outstanding shares of common stock of the Company (the
         "Outstanding Company Common Stock") or (B) the combined voting power of
         the then outstanding voting securities of the Company entitled to vote
         generally in the election of directors (the "Outstanding Company Voting
         Securities"); provided, however, that for purposes of this subparagraph
         (c)(i) the following acquisitions shall not constitute a Change of
         Control: (w) any acquisition directly from the Company (excluding an
         acquisition by virtue of the exercise of a conversion privilege), (x)
         any acquisition by the Company,



                                       15

<PAGE>   19



         (y) any acquisition by any employee benefit plan (or related trust)
         sponsored or maintained by the Company or any corporation controlled by
         the Company, or (z) any acquisition by any corporation pursuant to a
         reorganization, merger, or consolidation, if, following such
         reorganization, merger, or consolidation, the conditions described in
         clauses (A), (B), and (C) of subparagraph (iii) of this Paragraph 10
         (c) are satisfied; or

                      (ii) individuals who, as of the date of this Agreement,
         constitute the Board (the "Incumbent Board") cease for any reason to
         constitute a majority of the Board; provided, however, that any
         individual becoming a director subsequent to the date hereof whose
         election, or nomination for election by the Company's stockholders, was
         approved by a vote of a majority of the directors then comprising the
         Incumbent Board shall be considered as though such individual were a
         member of the Incumbent Board, but excluding, for this purpose, any
         such individual whose initial assumption of office occurs as a result
         of either an actual or threatened election contest or other actual or
         threatened solicitation of proxies or consents by or on behalf of a
         Person other than the Board; or

                      (iii) consummation of a reorganization, merger, or
         consolidation of the Company, with or without approval by the
         stockholders of the Company, in each case, unless, following such
         reorganization, merger, or consolidation, (A) more than 50% of,
         respectively, the then outstanding shares of common stock of the
         corporation resulting from such reorganization, merger, or
         consolidation and the combined voting power of the then outstanding
         voting securities of such corporation entitled to vote generally in the
         election of directors is then beneficially owned, directly or
         indirectly, by all or substantially all of the individuals and entities
         who were the beneficial owners, respectively, of the Outstanding
         Company Common Stock and Outstanding Company Voting Securities
         immediately prior to such reorganization, merger, or consolidation in
         substantially the same proportions as their ownership, immediately
         prior to such reorganization, merger, or consolidation, of the
         Outstanding Company Common Stock and Outstanding Company Voting
         Securities, as the case may be, (B) no Person (excluding the Company,
         any employee benefit plan (or related trust) of the Company or such
         corporation resulting from such reorganization, merger, or
         consolidation, and any Person beneficially owning, immediately prior to
         such reorganization, merger, or consolidation, directly or indirectly,
         15% or more of the Outstanding Company Common Stock or Outstanding
         Company Voting Securities, as the case may be) beneficially owns,
         directly or indirectly, 15% or more of, respectively, the then
         outstanding shares of common stock of the corporation resulting from
         such reorganization, merger, or consolidation or the combined voting
         power of the then outstanding voting securities of such corporation
         entitled to vote generally in the election of directors, and (C) a
         majority of the members of the board of directors of the corporation
         resulting from such reorganization, merger, or consolidation were
         members of the Incumbent Board at the time of the execution of the
         initial agreement providing for such reorganization, merger, or
         consolidation; or

                      (iv) consummation of a sale or other disposition of all or
         substantially all the assets of the Company, with or without approval
         by the stockholders of the Company, other than to a corporation, with
         respect to which following such sale or other disposition,

                                       16

<PAGE>   20



         (A) more than 50% of, respectively, the then outstanding shares of
         common stock of such corporation and the combined voting power of the
         then outstanding voting securities of such corporation entitled to vote
         generally in the election of directors is then beneficially owned,
         directly or indirectly, by all or substantially all the individuals and
         entities who were the beneficial owners, respectively, of the
         Outstanding Company Common Stock and Outstanding Company Voting
         Securities immediately prior to such sale or other disposition in
         substantially the same proportion as their ownership, immediately prior
         to such sale or other disposition, of the Outstanding Company Common
         Stock and Outstanding Company Voting Securities, as the case may be,
         (B) no Person (excluding the Company, any employee benefit plan (or
         related trust) of the Company or such corporation, and any Person
         beneficially owning, immediately prior to such sale or other
         disposition, directly or indirectly, 15% or more of the Outstanding
         Company Common Stock or Outstanding Company Voting Securities, as the
         case may be) beneficially owns, directly or indirectly, 15% or more of,
         respectively, the then outstanding shares of common stock of such
         corporation or the combined voting power of the then outstanding voting
         securities of such corporation entitled to vote generally in the
         election of directors, and (C) a majority of the members of the board
         of directors of such corporation were members of the Incumbent Board at
         the time of the execution of the initial agreement or action of the
         Board providing for such sale or other disposition of assets of the
         Company; or

                      (v) approval by the stockholders of the Company of a
         complete liquidation or dissolution of the Company.

         11. Full Settlement.

         (a) There shall be no right of set off or counterclaim against, or
delay in, any payments to the Executive, or to the Executive's heirs or legal
representatives, provided for in this Agreement, in respect of any claim against
or debt or other obligation of the Executive or others, whether arising
hereunder or otherwise.

         (b) In no event shall the Executive be obligated to seek other
employment or take any other action by way of mitigation of the amounts payable
to the Executive under any of the provisions of this Agreement, and such amounts
shall not be reduced whether or not the Executive obtains other employment.

         (c) The Company agrees to pay as incurred, to the full extent permitted
by law, all costs and expenses (including attorneys' fees) that the Executive,
or the Executive's heirs or legal representatives, may reasonably incur as a
result of any contest (regardless of the outcome thereof) by the Company, the
Executive, or others of the validity or enforceability of, or liability under,
any provision of this Agreement, or any guarantee of performance thereof
(including as a result of any contest by the Executive, or the Executive's heirs
or legal representatives, about the amount of any payment pursuant to this
Agreement), plus in each case interest on any delayed payment at the applicable
federal rate provided for in Section 7872(f)(2) of the Code.


                                       17

<PAGE>   21



         12. No Effect on Other Contractual Rights. The provisions of this
Agreement, and any payment provided for hereunder, shall not reduce any amounts
otherwise payable to the Executive, or in any way diminish the Executive's
rights as an employee of the Company, whether existing on the date of this
Agreement or hereafter, under any employee benefit plan, program, or arrangement
or other contract or agreement of the Company providing benefits to the
Executive.

         13. Indemnification; Directors and Officers Insurance. The Company
shall (a) during the Employment Term and thereafter without limitation of time,
indemnify and advance expenses to the Executive to the fullest extent permitted
by the laws of the State of Delaware from time to time in effect and (b) during
the Employment Term, acquire and maintain directors and officers liability
insurance covering the Executive (and to the extent the Company desires, other
directors and officers of the Company and its affiliated companies) to the
extent it is available at commercially reasonable rates as determined by the
Board; provided, however, that in no event shall the Executive be entitled to
indemnification or advancement of expenses under this Paragraph 13 with respect
to any proceeding, or matter therein, brought or made by the Executive against
the Company other than one initiated by the Executive to enforce the Executive's
rights under this Paragraph 13. The rights of indemnification and to receive
advancement of expenses as provided in this Paragraph 13 shall not be deemed
exclusive of any other rights to which the Executive may at any time be entitled
under applicable law, the certificate of incorporation or bylaws of the Company,
any agreement, a vote of stockholders, a resolution of the Board, or otherwise.
The provisions of this Paragraph 13 shall continue in effect notwithstanding
termination of the Executive's employment hereunder for any reason.

         14. Injunctive Relief. In recognition of the fact that a breach by the
Executive of any of the provisions of Paragraph 9 will cause irreparable damage
to the Company for which monetary damages alone will not constitute an adequate
remedy, the Company shall be entitled as a matter of right (without being
required to prove damages or furnish any bond or other security) to obtain a
restraining order, an injunction, an order of specific performance, or other
equitable or extraordinary relief from any court of competent jurisdiction
restraining any further violation of such provisions by the Executive or
requiring the Executive to perform the Executive's obligations hereunder. Such
right to equitable or extraordinary relief shall not be exclusive but shall be
in addition to all other rights and remedies to which the Company may be
entitled at law or in equity, including without limitation the right to recover
monetary damages for the breach by the Executive of any of the provisions of
this Agreement.

         15. Governing Law. This Agreement shall be governed by and construed
and enforced in accordance with the laws of the State of Texas, without regard
to the principles of conflicts of laws thereof.

         16. Notices. All notices, requests, demands, and other communications
required or permitted to be given or made hereunder by either party hereto shall
be in writing and shall be deemed to have been duly given or made (i) when
delivered personally, (ii) when sent by telefacsimile transmission, or (iii)
five days after being deposited in the United States mail, first class
registered or certified mail, postage prepaid, return receipt requested, to the
party for which

                                       18

<PAGE>   22



intended at the following addresses (or at such other addresses as shall be
specified by the parties by like notice, except that notices of change of
address shall be effective only upon receipt):

             If to the Company, at:    Noble Drilling Corporation
                                       10370 Richmond Avenue, Suite 400
                                       Houston, Texas 77042
                                       Fax No.:  713-974-3181
                                       Attention: Chief Executive Officer

             If to the Executive, at:  Byron L. Welliver
                                       Noble Drilling Corporation
                                       10370 Richmond Avenue, Suite 400
                                       Houston, Texas  77042
                                       Fax No.: 713-974-3181

         17. Binding Effect; Assignment; No Third Party Benefit.

         (a) This Agreement is personal to the Executive and without the prior
written consent of the Company shall not be assignable by the Executive
otherwise than by will or the laws of descent and distribution. This Agreement
shall inure to the benefit of and shall be enforceable by the Executive's legal
representatives.

         (b) This Agreement shall inure to the benefit of and be binding upon
the Company and its successors and assigns.

         (c) The Company shall require any successor or assign (whether direct
or indirect, by purchase, merger, consolidation, or otherwise) to all or
substantially all the business and/or assets of the Company, by agreement in
writing in form and substance reasonably satisfactory to the Executive,
expressly, absolutely, and unconditionally to assume and agree to perform this
Agreement in the same manner and to the same extent that the Company would be
required to perform it if no such succession or assignment had taken place. As
used in this Agreement, the "Company" shall mean the Company as hereinbefore
defined and any successor or assign to its business and/or assets as aforesaid
which executes and delivers the agreement provided for in this Paragraph 17(c)
or which otherwise becomes bound by all the terms and provisions of this
Agreement by operation of law.

         (d) Nothing in this Agreement, express or implied, is intended to or
shall confer upon any person other than the parties hereto, and their respective
heirs, legal representatives, successors, and permitted assigns, any rights,
benefits, or remedies of any nature whatsoever under or by reason of this
Agreement.

         18. Miscellaneous.

         (a) Amendment. This Agreement may not be modified or amended in any
respect except by an instrument in writing signed by the party against whom such
modification or amendment is sought to be enforced. No person, other than
pursuant to a resolution of the Board

                                       19

<PAGE>   23



or a committee thereof, shall have authority on behalf of the Company to agree
to modify, amend, or waive any provision of this Agreement or anything in
reference thereto.

         (b) Waiver. Any term or condition of this Agreement may be waived at
any time by the party hereto which is entitled to have the benefit thereof, but
such waiver shall only be effective if evidenced by a writing signed by such
party, and a waiver on one occasion shall not be deemed to be a waiver of the
same or any other type of breach on a future occasion. No failure or delay by a
party hereto in exercising any right or power hereunder shall operate as a
waiver thereof nor shall any single or partial exercise thereof preclude any
other or further exercise thereof or the exercise of any other right or power.

         (c) Withholding Taxes. The Company may withhold from any amounts
payable under this Agreement such federal, state, local, or foreign taxes as
shall be required to be withheld pursuant to any applicable law or regulation.

         (d) Nonalienation of Benefits. The Executive shall not have any right
to pledge, hypothecate, anticipate, or in any way create a lien upon any
payments or other benefits provided under this Agreement; and no benefits
payable hereunder shall be assignable in anticipation of payment either by
voluntary or involuntary acts, or by operation of law, except by will or
pursuant to the laws of descent and distribution.

         (e) Severability. If any provision of this Agreement is held to be
invalid or unenforceable, (a) this Agreement shall be considered divisible, (b)
such provision shall be deemed inoperative to the extent it is deemed invalid or
unenforceable, and (c) in all other respects this Agreement shall remain in full
force and effect; provided, however, that if any such provision may be made
valid or enforceable by limitation thereof, then such provision shall be deemed
to be so limited and shall be valid and/or enforceable to the maximum extent
permitted by applicable law.

         (f) Entire Agreement. This Agreement constitutes the entire agreement
between the parties hereto concerning the subject matter hereof, and from and
after the date of this Agreement, this Agreement shall supersede any other prior
agreement or understanding, both written and oral, between the parties with
respect to such subject matter.

         (g) Captions. The captions herein are inserted for convenience of
reference only, do not constitute a part of this Agreement, and shall not affect
in any manner the meaning or interpretation of this Agreement.

         (h) References. All references in this Agreement to Paragraphs,
subparagraphs, and other subdivisions refer to the Paragraphs, subparagraphs,
and other subdivisions of this Agreement unless expressly provided otherwise.
The words "this Agreement", "herein", "hereof", "hereby", "hereunder", and words
of similar import refer to this Agreement as a whole and not to any particular
subdivision unless expressly so limited. Whenever the words "include",
"includes", and "including" are used in this Agreement, such words shall be
deemed to be followed by the words "without limitation". Words in the singular
form shall be construed to include the plural and vice versa, unless the context
otherwise requires.

                                       20

<PAGE>   24



         IN WITNESS WHEREOF, the Company has caused this Agreement to be
executed on its behalf by its duly authorized officer, and the Executive has
executed this Agreement, as of the date first above set forth.



                             NOBLE DRILLING CORPORATION


                             By: /S/ JAMES C. DAY
                                 ---------------------------------------------
                                 Name:  James C. Day
                                 Title: Chairman, Chief Executive Officer 
                                        and President

                                                                       "COMPANY"



                             /S/ BYRON L. WELLIVER
                             -------------------------------------------------
                             Byron L. Welliver

                                                                     "EXECUTIVE"



                                       21

<PAGE>   1
                                                                    EXHIBIT 10.3

================================================================================

                              EMPLOYMENT AGREEMENT



                                 BY AND BETWEEN


                           NOBLE DRILLING CORPORATION


                                       AND


                               JULIE J. ROBERTSON



                                October 22, 1998




================================================================================




<PAGE>   2



                              EMPLOYMENT AGREEMENT
                                TABLE OF CONTENTS

<TABLE>
<CAPTION>
                                                                            Page
                                                                            ----
<S>                                                                            <C>
1.  Employment ..........................................................      1

2.  Employment Term .....................................................      1
    (a) Term ............................................................      1
    (b) Relationship Prior to Effective Date ............................      1

3.  Positions and Duties ................................................      2

4.  Compensation and Related Matters ....................................      3
    (a) Base Salary .....................................................      3
    (b) Annual Bonus ....................................................      3
    (c) Employee Benefits ...............................................      4
        (i)  Incentive, Savings, and Retirement Plans ...................      4
        (ii) Welfare Benefit Plans ......................................      4
    (d) Expenses ........................................................      4
    (e) Fringe Benefits .................................................      4
    (f) Vacation ........................................................      5

5.  Termination of Employment ...........................................      5
    (a)  Death ..........................................................      5
    (b)  Disability .....................................................      5
    (c)  Termination by Company .........................................      5
    (d)  Termination by Executive .......................................      6
    (e)  Notice of Termination ..........................................      7
    (f)  Date of Termination ............................................      7

6.  Obligations of the Company Upon Termination .........................      8
    (a)  Good Reason or During the Window Period; Other Than for
         Cause, Death, or Disability ....................................      8
    (b)  Death ..........................................................     10
    (c)  Disability .....................................................     11
    (d)  Cause; Other Than for Good Reason or During the Window
         Period .........................................................     11

7.  Certain Additional Payments by the Company ..........................     12

8.  Representations and Warranties ......................................     14

9.  Confidential Information ............................................     14
</TABLE>


                                        i
<PAGE>   3

<TABLE>
<CAPTION>
                                                                            Page
                                                                            ----
<S>                                                                            <C>
10. Certain Definitions .................................................     15
    (a)  Effective Date .................................................     15
    (b)  Change of Control Period .......................................     15
    (c)  Change of Control ..............................................     15

11. Full Settlement .....................................................     17

12. No Effect on Other Contractual Rights ...............................     18

13. Indemnification; Directors and Officers Insurance ...................     18

14. Injunctive Relief ...................................................     18

15. Governing Law .......................................................     18

16. Notices .............................................................     18

17. Binding Effect; Assignment; No Third Party Benefit ..................     19

18. Miscellaneous .......................................................     19
    (a)  Amendment ......................................................     19
    (b)  Waiver .........................................................     20
    (c)  Withholding Taxes ..............................................     20
    (d)  Nonalienation of Benefits ......................................     20
    (e)  Severability ...................................................     20
    (f)  Entire Agreement ...............................................     20
    (g)  Captions .......................................................     20
    (h)  References .....................................................     20
</TABLE>


                                       ii

<PAGE>   4



                              EMPLOYMENT AGREEMENT

         This EMPLOYMENT AGREEMENT (this "Agreement"), dated as of October 22,
1998, by and between NOBLE DRILLING CORPORATION, a Delaware corporation (the
"Company"), and JULIE J. ROBERTSON (the "Executive");

                                   WITNESSETH:

         WHEREAS, the Board of Directors of the Company (the "Board") has
determined that it is in the best interests of the Company and its stockholders
to assure that the Company will have the continued dedication of the Executive,
notwithstanding the possibility, threat, or occurrence of a Change of Control
(as defined in Paragraph 10(c)) of the Company; and

         WHEREAS, the Board believes it is imperative to diminish the inevitable
distraction of the Executive by virtue of the personal uncertainties and risks
created by a pending or threatened Change of Control and to encourage the
Executive's full attention and dedication to the Company currently and in the
event of any pending or threatened Change of Control, and to provide the
Executive with compensation and benefits upon a Change of Control which ensure
that the compensation and benefits expectations of the Executive will be
satisfied and which are competitive with those of other corporations; and

         WHEREAS, in order to accomplish these objectives, the Board has caused
the Company to enter into this Agreement;

         NOW, THEREFORE, in consideration of the premises and the mutual
covenants and agreements herein contained, and intending to be legally bound
hereby, the Company and the Executive hereby agree as follows:

         1. Employment. The Company agrees that the Company or an affiliated
company (as hereafter defined) will continue the Executive in its employ, and
the Executive agrees to remain in the employ of the Company or an affiliated
company, for the period set forth in Paragraph 2(a), in the positions and with
the duties and responsibilities set forth in Paragraph 3, and upon the other
terms and conditions herein provided. As used in this Agreement, the term
"affiliated company" shall include any company controlled by, controlling, or
under common control with the Company.

         2. Employment Term.

         (a) Term. The employment of the Executive by the Company as provided in
Paragraph 1 shall be for the period commencing on the Effective Date (as defined
in Paragraph 10 (a)) through and ending on the third anniversary of such date
(the "Employment Term").

         (b) Relationship Prior to Effective Date. The Executive and the Company
acknowledge that, except as may otherwise be provided under any written
agreement between the Executive and the Company other than this Agreement, the
employment of the Executive by the

                                        1

<PAGE>   5



Company is "at will" and, prior to the Effective Date, may be terminated by
either the Executive or the Company at any time. Moreover, if prior to the
Effective Date, the Executive's employment with the Company terminates, then the
Executive shall have no further rights under this Agreement. For purposes of
this Paragraph 2(b) only, the term Company shall mean and include the company
that employs Executive, whether Noble Drilling Corporation or an affiliated
company of Noble Drilling Corporation.

         3. Positions and Duties.

         (a) During the Employment Term, the Executive's position (including
status, offices, titles, and reporting requirements), duties, functions,
responsibilities, and authority shall be at least commensurate in all material
respects with the most significant of those held or exercised by or assigned to
the Executive in respect of the Company and its affiliated companies at any time
during the 120-day period immediately preceding the Effective Date.

         (b) During the Employment Term, the Executive shall devote the
Executive's full time, skill, and attention and the Executive's reasonable best
efforts during normal business hours to the business and affairs of the Company,
and in furtherance of the business and affairs of its affiliated companies, to
the extent necessary to discharge faithfully and efficiently the duties and
responsibilities delegated and assigned to the Executive herein or pursuant
hereto, except for usual, ordinary, and customary periods of vacation and
absence due to illness or other disability; provided, however, that the
Executive may (i) serve on industry-related, civic or charitable boards or
committees, (ii) with the approval of the Board, serve on corporate boards or
committees, (iii) deliver lectures, fulfill speaking engagements, or teach at
educational institutions, and (iv) manage the Executive's personal investments,
so long as such activities do not significantly interfere with the performance
and fulfillment of the Executive's duties and responsibilities as an employee of
the Company or an affiliated company in accordance with this Agreement and, in
the case of the activities described in clause (ii) of this proviso, will not,
in the good faith judgment of the Board, constitute an actual or potential
conflict of interest with the business of the Company or an affiliated company.
It is expressly understood and agreed that, to the extent that any such
activities have been conducted by the Executive during the term of the
Executive's employment by the Company or its affiliated companies prior to the
Effective Date consistent with the provisions of this Paragraph 3(b), the
continued conduct of such activities (or of activities similar in nature and
scope thereto) subsequent to the Effective Date shall not thereafter be deemed
to interfere with the performance and fulfillment of the Executive's duties and
responsibilities to the Company.

         (c) In connection with the Executive's employment hereunder, the
Executive shall be based at the location where the Executive was regularly
employed immediately prior to the Effective Date or any office which is the
headquarters of the Company and is less than 50 miles from such location,
subject, however, to required travel on the business of the Company to an extent
substantially consistent with the Executive's business travel obligations during
the three-year period immediately preceding the Effective Date.


                                        2

<PAGE>   6



         (d) All services that the Executive may render to the Company or any of
its affiliated companies in any capacity during the Employment Term shall be
deemed to be services required by this Agreement and consideration for the
compensation provided for herein.

         4. Compensation and Related Matters.

         (a) Base Salary. During the Employment Term, the Executive shall
receive an annual base salary ("Base Salary") at least equal to 12 times the
highest monthly base salary paid or payable, including any base salary that has
been earned but deferred, to the Executive by the Company and its affiliated
companies in respect of the 12-month period immediately preceding the month in
which the Effective Date occurs. The Base Salary shall be payable in
installments in accordance with the general payroll practices of the Company in
effect at the time such payment is made, but in no event less frequently than
monthly, or as otherwise mutually agreed upon. During the Employment Term, the
Executive's Base Salary shall be subject to such increases (but not decreases)
as may be determined from time to time by the Board in its sole discretion;
provided, however, that the Executive's Base Salary (i) shall be reviewed by the
Board no later than 12 months after the last salary increase awarded to the
Executive prior to the Effective Date and thereafter at least annually, with a
view to making such upward adjustment, if any, as the Board deems appropriate,
and (ii) shall be increased at any time and from time to time as shall be
substantially consistent with increases in base salary generally awarded in the
ordinary course of business to the Executive's peer executives of the Company or
any of its affiliated companies. Base Salary shall not be reduced after any such
increase. The term Base Salary as used in this Agreement shall refer to the Base
Salary as so increased. Payments of Base Salary to the Executive shall not be
deemed exclusive and shall not prevent the Executive from participating in any
employee benefit plans, programs, or arrangements of the Company and its
affiliated companies in which the Executive is entitled to participate. Payments
of Base Salary to the Executive shall not in any way limit or reduce any other
obligation of the Company hereunder, and no other compensation, benefit, or
payment to the Executive hereunder shall in any way limit or reduce the
obligation of the Company regarding the Executive's Base Salary hereunder.

         (b) Annual Bonus. In addition to Base Salary, the Executive shall be
awarded, in respect of each fiscal year of the Company ending during the
Employment Term, an annual bonus (the "Annual Bonus") in cash in an amount at
least equal to the Executive's highest aggregate bonus under all Company bonus
plans, programs, arrangements, and awards (including the Company's Short-Term
Incentive Plan and any successor plan), in respect of any fiscal year in the
three full fiscal year period ended immediately prior to the Effective Date
(annualized for any fiscal year consisting of less than 12 full months or with
respect to which the Executive has been employed by the Company for less than 12
full months) (such highest amount is hereinafter referred to as the "Recent
Annual Bonus"). Each such Annual Bonus shall be paid no later than the end of
the third month of the fiscal year next following the fiscal year in respect of
which the Annual Bonus is awarded, unless the Executive shall elect to defer the
receipt of such Annual Bonus.


                                        3

<PAGE>   7



         (c) Employee Benefits.

                      (i) Incentive, Savings, and Retirement Plans. During the
         Employment Term, the Executive shall be entitled to participate in all
         incentive, savings, and retirement plans, programs, and arrangements
         applicable generally to the Executive's peer executives of the Company
         and its affiliated companies, but in no event shall such plans,
         programs, and arrangements provide the Executive with incentive
         opportunities (measured with respect to both regular and special
         incentive opportunities, to the extent, if any, that such distinction
         is applicable), savings opportunities, and retirement benefit
         opportunities, in each case, less favorable, in the aggregate, than the
         most favorable of those provided by the Company and its affiliated
         companies for the Executive under such plans, programs, and
         arrangements as in effect at any time during the 120-day period
         immediately preceding the Effective Date or, if more favorable to the
         Executive, those provided generally at any time after the Effective
         Date to the Executive's peer executives of the Company and its
         affiliated companies.

                      (ii) Welfare Benefit Plans. During the Employment Term,
         the Executive and/or the Executive's family, as the case may be, shall
         be eligible to participate in and shall receive all benefits under all
         welfare benefit plans, programs, and arrangements provided by the
         Company and its affiliated companies (including, without limitation,
         medical, prescription, dental, disability, salary continuance, employee
         life, group life, accidental death, and travel accident insurance
         plans, programs, and arrangements) to the extent applicable generally
         to the Executive's peer executives of the Company and its affiliated
         companies, but in no event shall such plans, programs, and arrangements
         provide the Executive with welfare benefits that are less favorable, in
         the aggregate, than the most favorable of such plans, programs, and
         arrangements as in effect for the Executive at any time during the
         120-day period immediately preceding the Effective Date or, if more
         favorable to the Executive, those provided generally at any time after
         the Effective Date to the Executive's peer executives of the Company
         and its affiliated companies.

         (d) Expenses. During the Employment Term, the Executive shall be
entitled to receive prompt reimbursement for all reasonable expenses incurred by
the Executive in performing the Executive's duties and responsibilities
hereunder, in accordance with the most favorable policies, practices, and
procedures of the Company and its affiliated companies as in effect for the
Executive at any time during the 120-day period immediately preceding the
Effective Date or, if more favorable to the Executive, as in effect generally at
any time thereafter with respect to the Executive's peer executives of the
Company and its affiliated companies.

         (e) Fringe Benefits. During the Employment Term, the Executive shall be
entitled to fringe benefits, including, without limitation, tax and financial
planning services, payment of club dues, and, if applicable, use of an
automobile and payment of related expenses, in accordance with the most
favorable policies, practices, and procedures of the Company and its affiliated
companies as in effect for the Executive at any time during the 120-day period
immediately preceding the Effective Date or, if more favorable to the Executive,
as in effect generally at any

                                        4

<PAGE>   8



time after the Effective Date with respect to the Executive's peer executives of
the Company and its affiliated companies.

         (f) Vacation. During the Employment Term, the Executive shall be
entitled to paid vacation and such other paid absences, whether for holidays,
illness, personal time, or any similar purposes, in accordance with the most
favorable policies, practices, and procedures of the Company and its affiliated
companies as in effect for the Executive at any time during the 120-day period
immediately preceding the Effective Date or, if more favorable to the Executive,
as in effect generally at any time after the Effective Date with respect to the
Executive's peer executives of the Company and its affiliated companies.

         5. Termination of Employment.

         (a) Death. The Executive's employment shall terminate automatically
upon the Executive's death during the Employment Term.

         (b) Disability. If the Company determines in good faith that the
Disability (as defined below) of the Executive has occurred during the
Employment Term, the Company may give the Executive notice of its intention to
terminate the Executive's employment. In such event, the Executive's employment
hereunder shall terminate effective on the 30th day after receipt of such notice
by the Executive (the "Disability Effective Date"), provided that, within the
30-day period after such receipt, the Executive shall not have returned to
full-time performance of the Executive's duties. For purposes of this Agreement,
"Disability" shall mean the absence of the Executive from the Executive's duties
hereunder on a full-time basis for an aggregate of 180 days within any given
period of 270 consecutive days (in addition to any statutorily required leave of
absence and any leave of absence approved by the Company), as a result of
incapacity of the Executive, despite any reasonable accommodation required by
law, due to bodily injury or disease or any other mental or physical illness,
which will, in the opinion of a physician selected by the Company or its
insurers and acceptable to the Executive or the Executive's legal
representative, be permanent and continuous during the remainder of the
Executive's life.

         (c) Termination by Company. The Company may terminate the Executive's
employment hereunder for Cause (as defined below). For purposes of this
Agreement, "Cause" shall mean:

                      (i) the willful and continued failure of the Executive to
         perform substantially the Executive's duties hereunder (other than any
         such failure resulting from bodily injury or disease or any other
         incapacity due to mental or physical illness), after a written demand
         for substantial performance is delivered to the Executive by the Board
         or the Chief Executive Officer of the Company which specifically
         identifies the manner in which the Board or Chief Executive Officer
         believes the Executive has not substantially performed the Executive's
         duties; or


                                        5

<PAGE>   9



                      (ii) the willful engaging by the Executive in illegal
         conduct or gross misconduct that is materially and demonstrably
         detrimental to the Company, monetarily or otherwise.

For purposes of this provision, no act, or failure to act, on the part of the
Executive shall be considered "willful" unless done, or omitted to be done, by
the Executive in bad faith or without reasonable belief that the Executive's
action or omission was in the best interests of the Company. Any act, or failure
to act, based upon authority given pursuant to a resolution duly adopted by the
Board or upon the instructions of the Chief Executive Officer or another senior
officer of the Company or based upon the advice of counsel for the Company shall
be conclusively presumed to be done, or omitted to be done, by the Executive in
good faith and in the best interests of the Company. The cessation of employment
of the Executive shall not be deemed to be for Cause unless and until there
shall have been delivered to the Executive a copy of a resolution duly adopted
by the affirmative vote of not less than two-thirds of the entire membership of
the Board then in office at a meeting of the Board called and held for such
purpose (after reasonable notice is provided to the Executive and the Executive
is given an opportunity, together with counsel, to be heard before the Board)
finding that, in the good faith opinion of the Board, the Executive is guilty of
the conduct described in subparagraph (i) or (ii) above, and specifying the
particulars thereof in detail.

         (d) Termination by Executive. The Executive may terminate the
Executive's employment hereunder (i) at any time during the Employment Term for
Good Reason (as defined below) or (ii) during the Window Period (as defined
below) without any reason.

For purposes of this Agreement, the "Window Period" shall mean the 30-day period
immediately following the first anniversary of the Effective Date, and "Good
Reason" shall mean any of the following (without the Executive's express written
consent):

                      (i) the assignment to the Executive of any duties
         inconsistent in any respect with the Executive's position (including
         status, offices, titles, and reporting requirements), duties,
         functions, responsibilities, or authority as contemplated by Paragraph
         3(a) of this Agreement, or any other action by the Company that results
         in a diminution in such position, duties, functions, responsibilities,
         or authority, excluding for this purpose an isolated, insubstantial,
         and inadvertent action not taken in bad faith and which is remedied by
         the Company promptly after receipt of notice thereof given by the
         Executive;

                      (ii) any failure by the Company to comply with any of the
         provisions of Paragraph 4 of this Agreement, other than an isolated,
         insubstantial, and inadvertent action not taken in bad faith and which
         is remedied by the Company promptly after receipt of notice thereof
         given by the Executive;

                      (iii) the Company's requiring the Executive to be based at
         any office or location other than as provided in Paragraph 3(c) of this
         Agreement or the Company's

                                        6

<PAGE>   10



         requiring the Executive to travel on Company business to a
         substantially greater extent than during the three-year period
         immediately preceding the Effective Date;

                      (iv) any failure by the Company to comply with and satisfy
         Paragraph 17(c) of this Agreement; or

                      (v) any purported termination by the Company of the
         Executive's employment hereunder otherwise than as expressly permitted
         by this Agreement, and for purposes of this Agreement, no such
         purported termination shall be effective.

For purposes of this Paragraph 5(d), any good faith determination of "Good
Reason" made by the Executive shall be conclusive.

         (e) Notice of Termination. Any termination of the Executive's
employment hereunder by the Company or by the Executive (other than a
termination pursuant to Paragraph 5(a)) shall be communicated by a Notice of
Termination (as defined below) to the other party hereto. For purposes of this
Agreement, a "Notice of Termination" shall mean a notice which (i) indicates the
specific termination provision in this Agreement relied upon, (ii) in the case
of a termination for Disability, Cause, or Good Reason, sets forth in reasonable
detail the facts and circumstances claimed to provide a basis for termination of
the Executive's employment under the provision so indicated, and (iii) specifies
the Date of Termination (as defined in Paragraph 5(f) below); provided, however,
that, notwithstanding any provision in this Agreement to the contrary, a Notice
of Termination given in connection with a termination for Good Reason shall be
given by the Executive within a reasonable period of time, not to exceed 120
days, following the occurrence of the event giving rise to such right of
termination. The failure by the Company or the Executive to set forth in the
Notice of Termination any fact or circumstance which contributes to a showing of
Disability, Cause, or Good Reason shall not waive any right of the Company or
the Executive hereunder or preclude the Company or the Executive from asserting
such fact or circumstance in enforcing the Company's or the Executive's rights
hereunder.

         (f) Date of Termination. For purposes of this Agreement, the "Date of
Termination" shall mean the effective date of termination of the Executive's
employment hereunder, which date shall be (i) if the Executive's employment is
terminated by the Executive's death, the date of the Executive's death, (ii) if
the Executive's employment is terminated because of the Executive's Disability,
the Disability Effective Date, (iii) if the Executive's employment is terminated
by the Company for Cause or by the Executive for Good Reason, the date on which
the Notice of Termination is given, (iv) if the Executive's employment is
terminated pursuant to Paragraph 2(a), the date on which the Employment Term
ends pursuant to Paragraph 2(a) due to a party's delivery of a Notice of
Termination thereunder, and (v) if the Executive's employment is terminated for
any other reason, the date specified in the Notice of Termination, which date
shall in no event be earlier than the date such notice is given; provided,
however, that if within 30 days after any Notice of Termination is given, the
party receiving such Notice of Termination notifies the other party that a
dispute exists concerning the termination, the Date of Termination shall be the
date on which the dispute is finally determined, either by mutual written
agreement

                                        7

<PAGE>   11



of the parties or by a final judgment, order, or decree of a court of competent
jurisdiction (the time for appeal therefrom having expired and no appeal having
been perfected).

         6. Obligations of the Company Upon Termination.

         (a) Good Reason or During the Window Period; Other Than for Cause,
Death, or Disability. If, during the Employment Term, the Company shall
terminate the Executive's employment hereunder other than for Cause or
Disability or the Executive shall terminate the Executive's employment either
for Good Reason or without any reason during the Window Period:

                      (i) the Company shall pay to the Executive in a lump sum
         in cash within 30 days after the Date of Termination the aggregate of
         the following amounts:

                                  (A) the sum of (1) the Executive's Base Salary
                      through the Date of Termination to the extent not
                      theretofore paid, (2) the product of (x) the greater of
                      (I) the Recent Annual Bonus and (II) the Annual Bonus paid
                      or payable, including by reason of any deferral, to the
                      Executive (and annualized for any fiscal year consisting
                      of less than 12 full months or for which the Executive has
                      been employed by the Company for less than 12 full months)
                      in respect of the most recently completed fiscal year of
                      the Company during the Employment Term, if any (such
                      greater amount hereinafter referred to as the "Highest
                      Annual Bonus"), and (y) a fraction, the numerator of which
                      is the number of days in the current fiscal year through
                      the Date of Termination, and the denominator of which is
                      365, and (3) any compensation previously deferred by the
                      Executive (together with any accrued interest or earnings
                      thereon) and any accrued vacation pay, in each case to the
                      extent not theretofore paid (the sum of the amounts
                      described in clauses (1), (2), and (3) are hereinafter
                      referred to as the "Accrued Obligations"); and

                                  (B) an amount (such amount is hereinafter
                      referred to as the "Severance Amount") equal to the
                      product of (1) three and (2) the sum of (x) the
                      Executive's Base Salary and (y) the Highest Annual Bonus;
                      and

                                  (C) a separate lump-sum supplemental
                      retirement benefit (the amount of such benefit hereinafter
                      referred to as the "Supplemental Retirement Amount") equal
                      to the difference between (1) the actuarial equivalent
                      (utilizing for this purpose the actuarial assumptions
                      utilized with respect to the qualified defined benefit
                      retirement plan of the Company and its affiliated
                      companies in which the Executive is eligible to
                      participate (or any successor plan thereto) (the
                      "Retirement Plan") during the 120-day period immediately
                      preceding the Effective Date) of the benefit payable under
                      the Retirement Plan and any supplemental and/or excess
                      retirement plan of the Company and its affiliated
                      companies providing benefits for the Executive (the
                      "SERP") which the Executive would receive if the
                      Executive's employment continued at the compensation level
                      provided for in Paragraphs 4(a) and 4(b)(i) for the
                      remainder

                                        8

<PAGE>   12



                      of the Employment Term, assuming for this purpose that all
                      accrued benefits are fully vested and that benefit accrual
                      formulas are no less advantageous to the Executive than
                      those in effect during the 120-day period immediately
                      preceding the Effective Date, and (2) the actuarial
                      equivalent (utilizing for this purpose the actuarial
                      assumptions utilized with respect to the Retirement Plan
                      during the 120-day period immediately preceding the
                      Effective Date) of the Executive's actual benefit (paid or
                      payable), if any, under the Retirement Plan and the SERP;
                      and

                      (ii) for three years after the Executives's Date of
         Termination, or such longer period as any plan, program, or arrangement
         may provide, the Company shall continue benefits to the Executive
         and/or the Executive's family at least equal to those that would have
         been provided to them in accordance with the plans, programs, and
         arrangements described in Paragraph 4(c)(ii) if the Executive's
         employment had not been terminated, in accordance with the most
         favorable plans, programs, and arrangements of the Company as in effect
         and applicable generally to the Executive's peer executives of the
         Company and its affiliated companies and their families during the
         120-day period immediately preceding the Effective Date or, if more
         favorable to the Executive, as in effect generally at any time
         thereafter with respect to the Executive's peer executives of the
         Company and its affiliated companies and their families; provided,
         however, that if the Executive becomes reemployed with another employer
         and is eligible to receive medical or other welfare benefits under
         another employer provided plan, the medical and other welfare benefits
         described herein shall be secondary to those provided under such other
         plan during such applicable period of eligibility (such continuation of
         such benefits for the applicable period herein set forth is hereinafter
         referred to as "Welfare Benefit Continuation") (for purpose of
         determining eligibility of the Executive for retiree benefits pursuant
         to such plans, programs, and arrangements, the Executive shall be
         considered to have remained employed until three years after the Date
         of Termination and to have retired on the last day of such period); and

                      (iii) the Company shall, at its sole expense as incurred,
         provide the Executive with outplacement services the scope and provider
         of which shall be selected by the Executive in the Executive's sole
         discretion; and

                      (iv) with respect to all options to purchase Common Stock
         held by the Executive pursuant to a Company stock option plan on or
         prior to the Date of Termination, irrespective of whether such options
         are then exercisable, the Executive shall have the right, during the
         60-day period after the Date of Termination, to elect to surrender all
         or part of such options in exchange for a cash payment by the Company
         to the Executive in an amount equal to the number of shares of Common
         Stock subject to the Executive's option multiplied by the excess of (x)
         over (y), where (x) equals the highest reported sale price of a share
         of Common Stock in any transaction reported on the New York Stock
         Exchange during the 60-day period prior to and including the
         Executive's Date of Termination and (y) equals the purchase price per
         share covered by the option. Such cash payments shall be made within 30
         days after the date of the Executive's election; provided,

                                        9

<PAGE>   13



         however, that if the Executive's Date of Termination is within six
         months after the date of grant of a particular option held by the
         Executive and the Executive is subject to Section 16(b) of the
         Securities Exchange Act of 1934, as amended (the "Exchange Act"), any
         cash payments related thereto shall be made on the date which is six
         months and one day after the date of grant of such option to the extent
         necessary to prevent the imposition of the disgorgement provisions
         under Section 16(b). Notwithstanding the foregoing, if any right
         granted pursuant to the foregoing would make any change of control
         transaction ineligible for pooling of interests accounting treatment
         under APB No. 16 that but for this Section 6(a)(iv) would otherwise be
         eligible for such accounting treatment, the Executive shall receive
         shares of Common Stock with a fair market value equal to the cash that
         would otherwise be payable hereunder in substitution for the cash,
         provided that any such shares of Common Stock so delivered to the
         Executive shall be registered under the Securities Act of 1933, as
         amended; any options outstanding as of the Date of Termination and not
         then exercisable shall become fully exercisable as of the Executive's
         Date of Termination, and to the extent the Executive does not elect to
         surrender same for a cash payment (or the equivalent number of shares
         of Common Stock) as provided above, such options shall remain
         exercisable after the Executive's Date of Termination in accordance
         with the terms thereof; and restrictions applicable to any shares of
         Common Stock awarded to the Executive by the Company shall lapse, as of
         the date of the Executive's Date of Termination; and

                      (v) all club memberships and other memberships that the
         Company was providing for the Executive's use at the time Notice of
         Termination is given shall, to the extent possible, be transferred and
         assigned to the Executive at no cost to the Executive (other than
         income taxes owed), the cost of transfer, if any, to be borne by the
         Company; and

                      (vi) all benefits under the Noble Drilling Corporation
         1991 Stock Option and Restricted Stock Plan and any other similar
         plans, including any stock options or restricted stock held by the
         Executive, not already vested shall be 100% vested, to the extent such
         vesting is permitted under the Code; and

                      (vii) to the extent not theretofore paid or provided, the
         Company shall timely pay or provide to the Executive any other amounts
         or benefits required to be paid or provided or which the Executive is
         eligible to receive under any plan, program, policy, practice, or
         arrangement or contract or agreement of the Company and its affiliated
         companies (such other amounts and benefits hereinafter referred to as
         the "Other Benefits").

         (b) Death. If the Executive's employment is terminated by reason of the
Executive's death during the Employment Term, this Agreement shall terminate
without further obligations to the Executive's legal representatives under this
Agreement, other than for (i) payment of Accrued Obligations (which shall be
paid to the Executive's estate or beneficiary, as applicable, in a lump sum in
cash within 30 days of the Date of Termination) and the timely payment or
provision of the Welfare Benefit Continuation and the Other Benefits and (ii)
payment to the

                                       10

<PAGE>   14



Executive's estate or beneficiaries, as applicable, in a lump sum in cash within
30 days of the Date of Termination of an amount equal to the sum of the
Severance Amount and the Supplemental Retirement Amount. With respect to the
provision of Other Benefits, the term Other Benefits as used in this Section
6(b) shall include, without limitation, and the Executive's estate and/or
beneficiaries shall be entitled to receive, benefits at least equal to the most
favorable benefits provided by the Company and affiliated companies to the
estates and beneficiaries of peer executives of the Company and such affiliated
companies under such plans, programs, practices, and policies relating to death
benefits, if any, as in effect with respect to other peer executives and their
beneficiaries at any time during the 120-day period immediately preceding the
Effective Date or, if more favorable to the Executive's estate and/or the
Executive's beneficiaries, as in effect on the date of the Executive's death
with respect to other peer executives of the Company and its affiliated
companies and their beneficiaries.

         (c) Disability. If the Executive's employment is terminated by reason
of the Executive's Disability during the Employment Term, this Agreement shall
terminate without further obligations to the Executive, other than for (i)
payment of Accrued Obligations (which shall be paid to the Executive in a lump
sum in cash within 30 days of the Date of Termination) and the timely payment or
provision of the Welfare Benefit Continuation and the Other Benefits and (ii)
payment to the Executive in a lump sum in cash within 30 days of the Date of
Termination of an amount equal to the sum of the Severance Amount and the
Supplemental Retirement Amount. With respect to the provision of Other Benefits,
the term Other Benefits as used in this Section 6(c) shall include, without
limitation, and the Executive shall be entitled after the Disability Effective
Date to receive, disability and other benefits at least equal to the most
favorable of those generally provided by the Company and affiliated companies to
disabled executives and/or their families in accordance with such plans,
programs, practices, and policies relating to disability, if any, as in effect
generally with respect to other peer executives and their families at any time
during the 120-day period immediately preceding the Effective Date or, if more
favorable to the Executive and/or the Executive's family, as in effect at any
time thereafter generally with respect to other peer executives of the Company
and its affiliated companies and their families.

         (d) Cause; Other Than for Good Reason or During the Window Period. If
the Executive's employment is terminated for Cause during the Employment Term,
this Agreement shall terminate without further obligations to the Executive
other than the obligation to pay to the Executive Base Salary through the Date
of Termination plus the amount of any compensation previously deferred by the
Executive, in each case to the extent theretofore unpaid. If the Executive
voluntarily terminates the Executive's employment during the Employment Term,
excluding a termination either for Good Reason or without any reason during the
Window Period, this Agreement shall terminate without further obligations to the
Executive, other than for Accrued Obligations and the timely payment or
provision of the Other Benefits. In such case, all Accrued Obligations shall be
paid to the Executive in a lump sum in cash within 30 days of the Date of
Termination subject to applicable laws and regulations.


                                       11

<PAGE>   15



         7. Certain Additional Payments by the Company.

         (a) Notwithstanding any provision in this Agreement to the contrary and
except as set forth below, if it shall be determined that any payment or
distribution by the Company to or for the benefit of the Executive (whether paid
or payable or distributed or distributable pursuant to the terms of this
Agreement or otherwise, but determined without regard to any additional payments
required pursuant to this Paragraph 7) (a "Payment") would be subject to the
excise tax imposed by Section 4999 of the Code or any interest or penalties are
incurred by the Executive with respect to such excise tax (such excise tax,
together with any such interest and penalties, are hereinafter collectively
referred to as the "Excise Tax"), then the Executive shall be entitled to
receive an additional payment (a "Gross-Up Payment") in an amount such that
after payment by the Executive of all taxes (including any interest or penalties
imposed with respect to such taxes), including any income taxes (and any
interest and penalties imposed with respect thereto) and Excise Tax imposed upon
the Gross-Up Payment, the Executive retains an amount of the Gross- Up Payment
equal to the Excise Tax imposed upon the Payments. Notwithstanding the foregoing
provisions of this Paragraph 7(a), if it shall be determined that the Executive
is entitled to a Gross-Up Payment, but that the Executive, after taking into
account the Payments and the Gross-Up Payment, would not receive a net after-tax
benefit of at least $50,000 (taking into account both income taxes and any
Excise Tax) as compared to the net after-tax proceeds to the Executive resulting
from an elimination of the Gross-Up Payment and a reduction of the Payments, in
the aggregate, to an amount (the "Reduced Amount") such that the receipt of
payments would not give rise to any Excise Tax, then no Gross-Up Payment shall
be made to the Executive and the Payments, in the aggregate, shall be reduced to
the Reduced Amount.

         (b) Subject to the provisions of Paragraph 7(c), all determinations
required to be made under this Paragraph 7, including whether and when a
Gross-Up Payment is required and the amount of such Gross-Up Payment and the
assumptions to be utilized in arriving at such determination, shall be made by
PricewaterhouseCoopers (the "Accounting Firm") or, as provided below, such other
certified public accounting firm as may be designated by the Executive, which
shall provide detailed supporting calculations both to the Company and the
Executive within 15 business days after the receipt of notice from the Executive
that there has been a Payment, or such earlier time as is requested by the
Company. If the Accounting Firm is serving as accountant or auditor for the
individual, entity, or group effecting the Change of Control, the Executive
shall have the option, in the Executive's sole discretion, to appoint another
nationally recognized accounting firm to make the determinations required
hereunder (which accounting firm shall then be referred to as the Accounting
Firm hereunder). All fees and expenses of the Accounting Firm shall be borne
solely by the Company. Any Gross-Up Payment, as determined pursuant to this
Paragraph 7, shall be paid by the Company to the Executive within five days of
the receipt of the Accounting Firm's determination. If the Accounting Firm
determines that no Excise Tax is payable by the Executive, it shall furnish the
Executive with a written opinion that failure to report the Excise Tax on the
Executive's applicable federal income tax return would not result in the
imposition of a negligence or similar penalty. Any determination by the
Accounting Firm shall be binding upon the Company and the Executive. As a result
of the uncertainty in the application of Section 4999 of the Code at the time of
the initial determination by the Accounting Firm hereunder, it is possible that
Gross-Up Payments that will not have been made by the Company

                                       12

<PAGE>   16



should have been made ("Underpayment"), consistent with the calculations
required to be made hereunder. If the Company exhausts its remedies pursuant to
Paragraph 7(c) and the Executive thereafter is required to make a payment of any
Excise Tax, the Accounting Firm shall determine the amount of the Underpayment
that has occurred and any such Underpayment shall be promptly paid by the
Company to or for the benefit of the Executive.

         (c) The Executive shall notify the Company in writing of any claim by
the Internal Revenue Service that, if successful, would require the payment by
the Company of the Gross-Up Payment (or an additional amount of Gross-Up
Payment) in the event the Internal Revenue Service seeks higher payment. Such
notification shall be given as soon as practicable but no later than 10 business
days after the Executive is informed in writing of such claim and shall apprise
the Company of the nature of such claim and the date on which such claim is
requested to be paid. The Executive shall not pay such claim prior to the
expiration of the 30-day period following the date on which it gives such notice
to the Company (or such shorter period ending on the date that any payment of
taxes with respect to such claim is due). If the Company notifies the Executive
in writing prior to the expiration of such period that it desires to contest
such claim, the Executive shall:

                  (i) give the Company any information reasonably requested by
         the Company relating to such claim;

                  (ii) take such action in connection with contesting such claim
         as the Company shall reasonably request in writing from time to time,
         including the acceptance of legal representation with respect to such
         claim by an attorney reasonably selected by the Company;

                  (iii) cooperate with the Company in good faith in order
         effectively to contest such claim; and

                  (iv) permit the Company to participate in any proceedings
         relating to such claim;

provided, however, that the Company shall bear and pay directly all costs and
expenses (including additional interest and penalties) incurred in connection
with such contest and shall indemnify and hold the Executive harmless, on an
after-tax basis, for any Excise Tax or income tax (including interest and
penalties with respect thereto) imposed as a result of such representation and
payment of costs and expenses. Without limitation of the foregoing provisions of
this Paragraph 7(c), the Company shall control all proceedings taken in
connection with such contest and, at its sole option, may pursue or forgo any
and all administrative appeals, proceedings, hearings, and conferences with the
taxing authority in respect of such claim and may, at its sole option, either
direct the Executive to pay the tax claimed and sue for a refund or contest the
claim in any permissible manner, and the Executive agrees to prosecute such
contest to a determination before any administrative tribunal, in a court of
initial jurisdiction, and in one or more appellate courts, as the Company shall
determine; provided, however, that if the Company directs the Executive to pay
such claim and sue for a refund, the Company shall advance the amount of such
payment to

                                       13

<PAGE>   17



the Executive, on an interest-free basis, and shall indemnify and hold the
Executive harmless, on an after-tax basis, from any Excise Tax or income tax
(including interest or penalties with respect thereto) imposed with respect to
such advance or with respect to any imputed income with respect to such advance;
and provided further that any extension of the statute of limitations relating
to payment of taxes for the taxable year of the Executive with respect to which
such contested amount is claimed to be due is limited solely to such contested
amount. Furthermore, the Company's control of the contest shall be limited to
issues with respect to which a Gross-Up Payment would be payable hereunder and
the Executive shall be entitled to settle or contest, as the case may be, any
other issue raised by the Internal Revenue Service or any other taxing
authority.

         (d) If, after the receipt by the Executive of an amount advanced by the
Company pursuant to Paragraph 7(c), the Executive becomes entitled to receive
any refund with respect to such claim, the Executive shall (subject to the
Company's complying with the requirements of Paragraph 7(c)) promptly pay to the
Company the amount of such refund (together with any interest paid or credited
thereon after taxes applicable thereto). If, after the receipt by the Executive
of an amount advanced by the Company pursuant to Paragraph 7(c), a determination
is made that the Executive shall not be entitled to any refund with respect to
such claim and the Company does not notify the Executive in writing of its
intent to contest such denial of refund prior to the expiration of 30 days after
such determination, then such advance shall be forgiven and shall not be
required to be repaid and the amount of such advance shall offset, to the extent
thereof, the amount of Gross-Up Payment required to be paid.

         8. Representations and Warranties.

         (a) The Company represents and warrants to the Executive that the
execution, delivery, and performance by the Company of this Agreement have been
duly authorized by all necessary corporate action of the Company and do not and
will not conflict with or result in a violation of any provision of, or
constitute a default under, any contract, agreement, instrument, or obligation
to which the Company is a party or by which it is bound.

         (b) The Executive represents and warrants to the Company that the
execution, delivery, and performance by the Executive of this Agreement do not
and will not conflict with or result in a violation of any provision of, or
constitute a default under, any contract, agreement, instrument, or obligation
to which the Executive is a party or by which the Executive is bound.

         9. Confidential Information. The Executive recognizes and acknowledges
that the Company's trade secrets and other confidential or proprietary
information, as they may exist from time to time, are valuable, special, and
unique assets of the Company's business, access to and knowledge of which are
essential to the performance of the Executive's duties hereunder. The Executive
confirms that all such trade secrets and other information constitute the
exclusive property of the Company. During the Employment Term and thereafter
without limitation of time, the Executive shall hold in strict confidence and
shall not, directly or indirectly, disclose or reveal to any person, or use for
the Executive's own personal benefit or for the benefit of anyone else, any
trade secrets, confidential dealings, or other confidential or proprietary
information of any kind, nature, or description (whether or not acquired,
learned, obtained, or developed by the

                                       14

<PAGE>   18



Executive alone or in conjunction with others) belonging to or concerning the
Company or any of its affiliated companies, except (i) with the prior written
consent of the Company duly authorized by its Board, (ii) in the course of the
proper performance of the Executive's duties hereunder, (iii) for information
(x) that becomes generally available to the public other than as a result of
unauthorized disclosure by the Executive or the Executive's affiliates or (y)
that becomes available to the Executive on a nonconfidential basis from a source
other than the Company or its affiliated companies who is not bound by a duty of
confidentiality, or other contractual, legal, or fiduciary obligation, to the
Company, or (iv) as required by applicable law or legal process. The provisions
of this Paragraph 9 shall continue in effect notwithstanding termination of the
Executive's employment hereunder for any reason.

         10. Certain Definitions.

         (a) Effective Date. The "Effective Date" shall mean the first date
during the Change of Control Period (as defined in Paragraph 10(b)) on which a
Change of Control occurs. Notwithstanding anything in this Agreement to the
contrary, if a Change of Control occurs and if the Executive's employment with
the Company is terminated prior to the date on which the Change of Control
occurs, and if it is reasonably demonstrated by the Executive that such
termination of employment (i) was at the request of a third party who has taken
steps reasonably calculated to effect a Change of Control or (ii) otherwise
arose in connection with or anticipation of a Change of Control, then for all
purposes of this Agreement the "Effective Date" shall mean the date immediately
prior to the date of such termination of employment.

         (b) Change of Control Period. The "Change of Control Period" shall mean
the period commencing on the date of this Agreement and ending on the third
anniversary of such date; provided, however, that commencing on the date one
year after the date hereof, and on each annual anniversary of such date (such
date and each annual anniversary thereof herein referred to as the "Renewal
Date"), the Change of Control Period shall be automatically extended so as to
terminate three years after such Renewal Date, unless at least 60 days prior to
the Renewal Date the Company shall give notice to the Executive that the Change
of Control Period shall not be so extended.

         (c) Change of Control. For purposes of this Agreement, a "Change of
Control" shall mean:

                      (i) the acquisition by any individual, entity, or group
         (within the meaning of Section 13(d)(3) or 14(d)(2) of the Exchange
         Act) (a "Person") of beneficial ownership (within the meaning of Rule
         13d-3 promulgated under the Exchange Act) of 15% or more of either (A)
         the then outstanding shares of common stock of the Company (the
         "Outstanding Company Common Stock") or (B) the combined voting power of
         the then outstanding voting securities of the Company entitled to vote
         generally in the election of directors (the "Outstanding Company Voting
         Securities"); provided, however, that for purposes of this subparagraph
         (c)(i) the following acquisitions shall not constitute a Change of
         Control: (w) any acquisition directly from the Company (excluding an
         acquisition by virtue of the exercise of a conversion privilege), (x)
         any acquisition by the Company,



                                       15

<PAGE>   19



         (y) any acquisition by any employee benefit plan (or related trust)
         sponsored or maintained by the Company or any corporation controlled by
         the Company, or (z) any acquisition by any corporation pursuant to a
         reorganization, merger, or consolidation, if, following such
         reorganization, merger, or consolidation, the conditions described in
         clauses (A), (B), and (C) of subparagraph (iii) of this Paragraph 10
         (c) are satisfied; or

                      (ii) individuals who, as of the date of this Agreement,
         constitute the Board (the "Incumbent Board") cease for any reason to
         constitute a majority of the Board; provided, however, that any
         individual becoming a director subsequent to the date hereof whose
         election, or nomination for election by the Company's stockholders, was
         approved by a vote of a majority of the directors then comprising the
         Incumbent Board shall be considered as though such individual were a
         member of the Incumbent Board, but excluding, for this purpose, any
         such individual whose initial assumption of office occurs as a result
         of either an actual or threatened election contest or other actual or
         threatened solicitation of proxies or consents by or on behalf of a
         Person other than the Board; or

                      (iii) consummation of a reorganization, merger, or
         consolidation of the Company, with or without approval by the
         stockholders of the Company, in each case, unless, following such
         reorganization, merger, or consolidation, (A) more than 50% of,
         respectively, the then outstanding shares of common stock of the
         corporation resulting from such reorganization, merger, or
         consolidation and the combined voting power of the then outstanding
         voting securities of such corporation entitled to vote generally in the
         election of directors is then beneficially owned, directly or
         indirectly, by all or substantially all of the individuals and entities
         who were the beneficial owners, respectively, of the Outstanding
         Company Common Stock and Outstanding Company Voting Securities
         immediately prior to such reorganization, merger, or consolidation in
         substantially the same proportions as their ownership, immediately
         prior to such reorganization, merger, or consolidation, of the
         Outstanding Company Common Stock and Outstanding Company Voting
         Securities, as the case may be, (B) no Person (excluding the Company,
         any employee benefit plan (or related trust) of the Company or such
         corporation resulting from such reorganization, merger, or
         consolidation, and any Person beneficially owning, immediately prior to
         such reorganization, merger, or consolidation, directly or indirectly,
         15% or more of the Outstanding Company Common Stock or Outstanding
         Company Voting Securities, as the case may be) beneficially owns,
         directly or indirectly, 15% or more of, respectively, the then
         outstanding shares of common stock of the corporation resulting from
         such reorganization, merger, or consolidation or the combined voting
         power of the then outstanding voting securities of such corporation
         entitled to vote generally in the election of directors, and (C) a
         majority of the members of the board of directors of the corporation
         resulting from such reorganization, merger, or consolidation were
         members of the Incumbent Board at the time of the execution of the
         initial agreement providing for such reorganization, merger, or
         consolidation; or

                      (iv) consummation of a sale or other disposition of all or
         substantially all the assets of the Company, with or without approval
         by the stockholders of the Company, other than to a corporation, with
         respect to which following such sale or other disposition,

                                       16

<PAGE>   20



         (A) more than 50% of, respectively, the then outstanding shares of
         common stock of such corporation and the combined voting power of the
         then outstanding voting securities of such corporation entitled to vote
         generally in the election of directors is then beneficially owned,
         directly or indirectly, by all or substantially all the individuals and
         entities who were the beneficial owners, respectively, of the
         Outstanding Company Common Stock and Outstanding Company Voting
         Securities immediately prior to such sale or other disposition in
         substantially the same proportion as their ownership, immediately prior
         to such sale or other disposition, of the Outstanding Company Common
         Stock and Outstanding Company Voting Securities, as the case may be,
         (B) no Person (excluding the Company, any employee benefit plan (or
         related trust) of the Company or such corporation, and any Person
         beneficially owning, immediately prior to such sale or other
         disposition, directly or indirectly, 15% or more of the Outstanding
         Company Common Stock or Outstanding Company Voting Securities, as the
         case may be) beneficially owns, directly or indirectly, 15% or more of,
         respectively, the then outstanding shares of common stock of such
         corporation or the combined voting power of the then outstanding voting
         securities of such corporation entitled to vote generally in the
         election of directors, and (C) a majority of the members of the board
         of directors of such corporation were members of the Incumbent Board at
         the time of the execution of the initial agreement or action of the
         Board providing for such sale or other disposition of assets of the
         Company; or

                      (v) approval by the stockholders of the Company of a
         complete liquidation or dissolution of the Company.

         11. Full Settlement.

         (a) There shall be no right of set off or counterclaim against, or
delay in, any payments to the Executive, or to the Executive's heirs or legal
representatives, provided for in this Agreement, in respect of any claim against
or debt or other obligation of the Executive or others, whether arising
hereunder or otherwise.

         (b) In no event shall the Executive be obligated to seek other
employment or take any other action by way of mitigation of the amounts payable
to the Executive under any of the provisions of this Agreement, and such amounts
shall not be reduced whether or not the Executive obtains other employment.

         (c) The Company agrees to pay as incurred, to the full extent permitted
by law, all costs and expenses (including attorneys' fees) that the Executive,
or the Executive's heirs or legal representatives, may reasonably incur as a
result of any contest (regardless of the outcome thereof) by the Company, the
Executive, or others of the validity or enforceability of, or liability under,
any provision of this Agreement, or any guarantee of performance thereof
(including as a result of any contest by the Executive, or the Executive's heirs
or legal representatives, about the amount of any payment pursuant to this
Agreement), plus in each case interest on any delayed payment at the applicable
federal rate provided for in Section 7872(f)(2) of the Code.


                                       17

<PAGE>   21



         12. No Effect on Other Contractual Rights. The provisions of this
Agreement, and any payment provided for hereunder, shall not reduce any amounts
otherwise payable to the Executive, or in any way diminish the Executive's
rights as an employee of the Company, whether existing on the date of this
Agreement or hereafter, under any employee benefit plan, program, or arrangement
or other contract or agreement of the Company providing benefits to the
Executive.

         13. Indemnification; Directors and Officers Insurance. The Company
shall (a) during the Employment Term and thereafter without limitation of time,
indemnify and advance expenses to the Executive to the fullest extent permitted
by the laws of the State of Delaware from time to time in effect and (b) during
the Employment Term, acquire and maintain directors and officers liability
insurance covering the Executive (and to the extent the Company desires, other
directors and officers of the Company and its affiliated companies) to the
extent it is available at commercially reasonable rates as determined by the
Board; provided, however, that in no event shall the Executive be entitled to
indemnification or advancement of expenses under this Paragraph 13 with respect
to any proceeding, or matter therein, brought or made by the Executive against
the Company other than one initiated by the Executive to enforce the Executive's
rights under this Paragraph 13. The rights of indemnification and to receive
advancement of expenses as provided in this Paragraph 13 shall not be deemed
exclusive of any other rights to which the Executive may at any time be entitled
under applicable law, the certificate of incorporation or bylaws of the Company,
any agreement, a vote of stockholders, a resolution of the Board, or otherwise.
The provisions of this Paragraph 13 shall continue in effect notwithstanding
termination of the Executive's employment hereunder for any reason.

         14. Injunctive Relief. In recognition of the fact that a breach by the
Executive of any of the provisions of Paragraph 9 will cause irreparable damage
to the Company for which monetary damages alone will not constitute an adequate
remedy, the Company shall be entitled as a matter of right (without being
required to prove damages or furnish any bond or other security) to obtain a
restraining order, an injunction, an order of specific performance, or other
equitable or extraordinary relief from any court of competent jurisdiction
restraining any further violation of such provisions by the Executive or
requiring the Executive to perform the Executive's obligations hereunder. Such
right to equitable or extraordinary relief shall not be exclusive but shall be
in addition to all other rights and remedies to which the Company may be
entitled at law or in equity, including without limitation the right to recover
monetary damages for the breach by the Executive of any of the provisions of
this Agreement.

         15. Governing Law. This Agreement shall be governed by and construed
and enforced in accordance with the laws of the State of Texas, without regard
to the principles of conflicts of laws thereof.

         16. Notices. All notices, requests, demands, and other communications
required or permitted to be given or made hereunder by either party hereto shall
be in writing and shall be deemed to have been duly given or made (i) when
delivered personally, (ii) when sent by telefacsimile transmission, or (iii)
five days after being deposited in the United States mail, first class
registered or certified mail, postage prepaid, return receipt requested, to the
party for which

                                       18

<PAGE>   22



intended at the following addresses (or at such other addresses as shall be
specified by the parties by like notice, except that notices of change of
address shall be effective only upon receipt):

             If to the Company, at:    Noble Drilling Corporation
                                       10370 Richmond Avenue, Suite 400
                                       Houston, Texas 77042
                                       Fax No.:  713-974-3181
                                       Attention: Chief Executive Officer

             If to the Executive, at:  Julie J. Robertson
                                       Noble Drilling Corporation
                                       10370 Richmond Avenue, Suite 400
                                       Houston, Texas  77042
                                       Fax No.: 713-974-3181

         17. Binding Effect; Assignment; No Third Party Benefit.

         (a) This Agreement is personal to the Executive and without the prior
written consent of the Company shall not be assignable by the Executive
otherwise than by will or the laws of descent and distribution. This Agreement
shall inure to the benefit of and shall be enforceable by the Executive's legal
representatives.

         (b) This Agreement shall inure to the benefit of and be binding upon
the Company and its successors and assigns.

         (c) The Company shall require any successor or assign (whether direct
or indirect, by purchase, merger, consolidation, or otherwise) to all or
substantially all the business and/or assets of the Company, by agreement in
writing in form and substance reasonably satisfactory to the Executive,
expressly, absolutely, and unconditionally to assume and agree to perform this
Agreement in the same manner and to the same extent that the Company would be
required to perform it if no such succession or assignment had taken place. As
used in this Agreement, the "Company" shall mean the Company as hereinbefore
defined and any successor or assign to its business and/or assets as aforesaid
which executes and delivers the agreement provided for in this Paragraph 17(c)
or which otherwise becomes bound by all the terms and provisions of this
Agreement by operation of law.

         (d) Nothing in this Agreement, express or implied, is intended to or
shall confer upon any person other than the parties hereto, and their respective
heirs, legal representatives, successors, and permitted assigns, any rights,
benefits, or remedies of any nature whatsoever under or by reason of this
Agreement.

         18. Miscellaneous.

         (a) Amendment. This Agreement may not be modified or amended in any
respect except by an instrument in writing signed by the party against whom such
modification or amendment is sought to be enforced. No person, other than
pursuant to a resolution of the Board

                                       19

<PAGE>   23



or a committee thereof, shall have authority on behalf of the Company to agree
to modify, amend, or waive any provision of this Agreement or anything in
reference thereto.

         (b) Waiver. Any term or condition of this Agreement may be waived at
any time by the party hereto which is entitled to have the benefit thereof, but
such waiver shall only be effective if evidenced by a writing signed by such
party, and a waiver on one occasion shall not be deemed to be a waiver of the
same or any other type of breach on a future occasion. No failure or delay by a
party hereto in exercising any right or power hereunder shall operate as a
waiver thereof nor shall any single or partial exercise thereof preclude any
other or further exercise thereof or the exercise of any other right or power.

         (c) Withholding Taxes. The Company may withhold from any amounts
payable under this Agreement such federal, state, local, or foreign taxes as
shall be required to be withheld pursuant to any applicable law or regulation.

         (d) Nonalienation of Benefits. The Executive shall not have any right
to pledge, hypothecate, anticipate, or in any way create a lien upon any
payments or other benefits provided under this Agreement; and no benefits
payable hereunder shall be assignable in anticipation of payment either by
voluntary or involuntary acts, or by operation of law, except by will or
pursuant to the laws of descent and distribution.

         (e) Severability. If any provision of this Agreement is held to be
invalid or unenforceable, (a) this Agreement shall be considered divisible, (b)
such provision shall be deemed inoperative to the extent it is deemed invalid or
unenforceable, and (c) in all other respects this Agreement shall remain in full
force and effect; provided, however, that if any such provision may be made
valid or enforceable by limitation thereof, then such provision shall be deemed
to be so limited and shall be valid and/or enforceable to the maximum extent
permitted by applicable law.

         (f) Entire Agreement. This Agreement constitutes the entire agreement
between the parties hereto concerning the subject matter hereof, and from and
after the date of this Agreement, this Agreement shall supersede any other prior
agreement or understanding, both written and oral, between the parties with
respect to such subject matter.

         (g) Captions. The captions herein are inserted for convenience of
reference only, do not constitute a part of this Agreement, and shall not affect
in any manner the meaning or interpretation of this Agreement.

         (h) References. All references in this Agreement to Paragraphs,
subparagraphs, and other subdivisions refer to the Paragraphs, subparagraphs,
and other subdivisions of this Agreement unless expressly provided otherwise.
The words "this Agreement", "herein", "hereof", "hereby", "hereunder", and words
of similar import refer to this Agreement as a whole and not to any particular
subdivision unless expressly so limited. Whenever the words "include",
"includes", and "including" are used in this Agreement, such words shall be
deemed to be followed by the words "without limitation". Words in the singular
form shall be construed to include the plural and vice versa, unless the context
otherwise requires.

                                       20

<PAGE>   24



         IN WITNESS WHEREOF, the Company has caused this Agreement to be
executed on its behalf by its duly authorized officer, and the Executive has
executed this Agreement, as of the date first above set forth.

                                 NOBLE DRILLING CORPORATION


                                 By: /S/ JAMES C. DAY
                                     -----------------------------------------
                                     Name:   James C. Day
                                     Title:  Chairman, Chief Executive Officer
                                             and President

                                                                       "COMPANY"



                                 /S/ JULIE J. ROBERTSON
                                 ---------------------------------------------
                                 Julie J. Robertson
                                 
                                                                     "EXECUTIVE"



                            21



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<RESTATED> 
<MULTIPLIER> 1,000
       
<S>                             <C>
<PERIOD-TYPE>                   9-MOS
<FISCAL-YEAR-END>                          DEC-31-1998
<PERIOD-END>                               SEP-30-1998
<CASH>                                          43,115
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                                0
                                          0
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<TOTAL-LIABILITY-AND-EQUITY>                 1,897,615
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