<PAGE>

                                                                    EXHIBIT 10.1
 
================================================================================

                            TRANSOCEAN OFFSHORE INC.

                (FORMERLY KNOWN AS SONAT OFFSHORE DRILLING INC.)

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

                  AMENDMENT NO. 1 TO NOTE PURCHASE AGREEMENTS

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

                         DATED AS OF SEPTEMBER 6, 1996



                                  $30,000,000


                    6.90% SENIOR NOTES DUE FEBRUARY 15, 2004


================================================================================
<PAGE>
 
                            TRANSOCEAN OFFSHORE INC.

                (FORMERLY KNOWN AS SONAT OFFSHORE DRILLING INC.)

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

                  AMENDMENT NO. 1 TO NOTE PURCHASE AGREEMENTS

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

                                  $30,000,000
                    6.90% SENIOR NOTES DUE FEBRUARY 15, 2004



                                                   Dated as of September 6, 1996


TO EACH OF THE CURRENT NOTEHOLDERS
NAMED IN ANNEX 1 HERETO:


Ladies and Gentlemen:

     TRANSOCEAN OFFSHORE INC. (formerly known as Sonat Offshore Drilling Inc.),
a Delaware corporation (together with any successors and assigns that become
such in accordance with the Note Purchase Agreements, the "COMPANY"), hereby
agrees with you as follows:

1.  PRIOR ISSUANCE OF NOTES, ETC.

     The Company issued and sold thirty million dollars ($30,000,000) in
aggregate principal amount of its six and ninety one-hundredths percent (6.90%)
Senior Notes due February 15, 2004 (as they may be amended, restated or
otherwise modified from time to time, and including each Note delivered from
time to time in accordance with any of the Note Purchase Agreements, the
"NOTES") pursuant to the separate Note Purchase Agreements, each dated as of
February 15,  1994, between the Company and the purchasers named in Annex 1
thereto (as in effect immediately prior to giving effect to the amendment
provided for by this Agreement, the "EXISTING NOTE PURCHASE AGREEMENTS" and, as
may be amended pursuant to this Agreement and as may be further amended,
restated or otherwise modified from time to time, the "NOTE PURCHASE
AGREEMENTS").  The entire original aggregate principal amount of the Notes
currently remains outstanding, although one or more Note transfers have
occurred.  The register kept by the Company pursuant to the Note Purchase
Agreements for the registration and transfer of the Notes indicates that each of
the Persons named in Annex 1 hereto (collectively, the "CURRENT NOTEHOLDERS") is
currently a holder of the aggregate principal amount of Notes indicated in such
Annex.

                                       1
<PAGE>
 
2.  REQUEST FOR CONSENT TO AMENDMENT

     The Company requests that each of you consent to the amendment to the
Existing Note Purchase Agreements provided for by this Agreement (the
"AMENDMENT").

3.  WARRANTIES AND REPRESENTATIONS

     To induce you to enter into this Agreement, and to induce you to consent to
the Amendment, the Company makes the warranties and representations set forth in
Attachment B, effective as of the date of the Company's execution of this
Agreement and as of the Amendment No. 1 Effective Date (as such term is defined
in Section 4.2), which are incorporated herein by reference with the same force
and effect as though set forth herein in full (it being agreed, however, that
nothing in this Section 3 or such Attachment or Attachment A or elsewhere in
this Agreement shall affect any of the warranties and representations previously
made by the Company in or pursuant to the Note Purchase Agreements, and that all
of such other warranties and representations, as well as the warranties and
representations in such Attachment, shall survive the Amendment No. 1 Effective
Date).

4.  AMENDMENT

     4.1  AMENDMENT OF EXISTING NOTE PURCHASE AGREEMENTS.

     Subject to Section 4.2, each of the Existing Note Purchase Agreements is
hereby amended in the manner specified in Attachment A.

     4.2  EFFECTIVENESS OF AMENDMENT.

     The amendment of each of the Existing Note Purchase Agreements contemplated
by Section 4.1 and Attachment A shall become effective, if at all, at the time
specified in Attachment C (the date, if any, on which the Amendment so becomes
effective is referred to herein as the "AMENDMENT NO. 1 EFFECTIVE DATE").

5.  DEFINED TERMS

     Capitalized terms used herein and not otherwise defined have the meanings
ascribed to them in the Note Purchase Agreements.

6.  EXPENSES

     Whether or not the Amendment becomes effective, the Company will promptly
(and in any event within thirty (30) days of receiving any statement or invoice
therefor) pay all fees, expenses and costs relating to this Agreement,
including, but not limited to, (a) the cost of reproducing this Agreement and
the other documents delivered in connection herewith and (b) the reasonable fees
and disbursements of your special counsel (namely, Hebb & Gitlin, a Professional
Corporation) incurred in connection with the preparation, negotiation and
delivery of this Agreement.

                                       2
<PAGE>
 
7.  MISCELLANEOUS

     7.1  PART OF NOTE PURCHASE AGREEMENTS, FUTURE REFERENCES, ETC.

     This Agreement shall be construed in connection with and as a part of each
of the Note Purchase Agreements and, except as expressly amended by this
Agreement, all terms, conditions and covenants contained in the Note Purchase
Agreements and the Notes are hereby ratified and shall be and remain in full
force and effect.  Any and all notices, requests, certificates and other
instruments executed and delivered after the execution and delivery of this
Agreement may refer to the Note Purchase Agreements and the Notes without making
specific reference to this Agreement, but nevertheless all such references shall
include this Agreement unless the context otherwise requires.  All references
herein to "THIS AGREEMENT" (other than such references in Attachment A where the
context requires that such references are to the Note Purchase Agreements) mean
this Amendment No. 1 to Note Purchase Agreements, as this Amendment No. 1 to
Note Purchase Agreements may be amended, restated or otherwise modified from
time to time.

     7.2  GOVERNING LAW.

     THIS AGREEMENT SHALL BE GOVERNED BY, AND CONSTRUED AND ENFORCED IN
ACCORDANCE WITH, THE LAW OF THE STATE OF NEW YORK, EXCLUDING CHOICE-OF-LAW
PRINCIPLES OF THE LAW OF SUCH STATE THAT WOULD REQUIRE THE APPLICATION OF THE
LAWS OF A JURISDICTION OTHER THAN SUCH STATE.

     7.3  DUPLICATE ORIGINALS, EXECUTION IN COUNTERPART.

     Two (2) or more duplicate originals hereof may be signed by the parties,
each of which shall be an original but all of which together shall constitute
one and the same instrument.  This Agreement may be executed in one or more
counterparts and shall be effective when at least one counterpart shall have
been executed by each party hereto, and each set of counterparts that,
collectively, show execution by the Company and each Current Noteholder shall
constitute one duplicate original.

     [REMAINDER OF PAGE INTENTIONALLY BLANK; NEXT PAGE IS SIGNATURE PAGE.]

                                       3
<PAGE>
 
     If this Agreement is satisfactory to you, please so indicate by signing the
applicable acceptance on a counterpart hereof and returning such counterpart to
the Company, whereupon this Agreement shall become binding between the Company
and you in accordance with its terms (provided that effectiveness of the
Amendment shall remain subject to the provisions of Section 4.2 and Attachment
C).

                                    Very truly yours,

                                    TRANSOCEAN OFFSHORE INC.



                                    By________________________________

                                      Name:

                                      Title:
<PAGE>
 
[SIGNATURE PAGE FOR AMENDMENT NO. 1 TO NOTE PURCHASE AGREEMENTS OF TRANSOCEAN
OFFSHORE INC. (FORMERLY KNOWN AS SONAT OFFSHORE DRILLING INC.) IN CONNECTION
WITH ITS 6.90% SENIOR NOTES DUE FEBRUARY 15, 2004]
<PAGE>
 
Accepted:

PRINCIPAL MUTUAL LIFE INSURANCE COMPANY



By____________________________________

  Name:

  Title:



By____________________________________

  Name:

  Title:
<PAGE>
 
[SIGNATURE PAGE FOR AMENDMENT NO. 1 TO NOTE PURCHASE AGREEMENTS OF TRANSOCEAN
OFFSHORE INC. (FORMERLY KNOWN AS SONAT OFFSHORE DRILLING INC.) IN CONNECTION
WITH ITS 6.90% SENIOR NOTES DUE FEBRUARY 15, 2004]
<PAGE>
 
Accepted:

PROVIDENT LIFE AND ACCIDENT INSURANCE COMPANY



By____________________________________

  Name:

  Title:



[SIGNATURE PAGE FOR AMENDMENT NO. 1 TO NOTE PURCHASE AGREEMENTS OF TRANSOCEAN
OFFSHORE INC. (FORMERLY KNOWN AS SONAT OFFSHORE DRILLING INC.) IN CONNECTION
WITH ITS 6.90% SENIOR NOTES DUE FEBRUARY 15, 2004]
<PAGE>
 
                                                                         ANNEX 1

                   CURRENT NOTEHOLDERS AND PRINCIPAL AMOUNTS
 
======================================================================== 
       NAME OF CURRENT NOTEHOLDER          AGGREGATE PRINCIPAL AMOUNT OF
                                                    NOTES HELD
========================================================================
 
Principal Mutual Life Insurance Company                      $20,000,000
------------------------------------------------------------------------
Provident Life and Accident                                  $10,000,000
Insurance Company
(Note registered in the name
of its nominee PEPA & CO.)
========================================================================

                                   Annex 1-1
<PAGE>
 
                                                                    ATTACHMENT A

                                   AMENDMENT


(S)A.1. SECTION 4 OF THE EXISTING NOTE PURCHASE AGREEMENTS IS AMENDED BY ADDING
        AT THE END THEREOF A NEW SECTION 4.6 TO READ AS FOLLOWS:

     "4.6 OFFER TO PREPAY UPON FAILURE TO OBTAIN INVESTMENT GRADE RATINGS

          (A) NOTICE AND OFFER.  If the Investment Grade Condition is not
     satisfied on or before March 31, 1997, the Company will, not later than
     April 2, 1997, give written notice of such failure to each Noteholder by
     facsimile transmission and, simultaneously with the sending of such
     telecopied notice, send a copy of such notice to each such Noteholder via
     an overnight courier of national reputation.  Such written notice shall
     contain, and such written notice shall constitute, an irrevocable offer to
     prepay all, but not less than all, the Notes held by such Noteholder on a
     date (which shall be a Business Day not earlier than May 15, 1997 and not
     later than June 30, 1997) specified by the Company in such notice (the "PUT
     PREPAYMENT DATE").  If the Company fails to specify the Put Prepayment
     Date, then the Put Prepayment Date shall be June 30, 1997.  If the Company
     shall not have received a written response to such notice from a Noteholder
     within ten (10) days after the delivery of such telecopied notice to such
     Noteholder, then the Company will immediately send a second such written
     notice to such Noteholder via an overnight courier of national reputation.

          (B) ACCEPTANCE AND PAYMENT.  To accept such offered prepayment, a
     Noteholder shall cause a notice of such acceptance to be delivered to the
     Company, by facsimile transmission, not later than May 9, 1997.  If so
     accepted, such offered prepayment shall be due and payable on the Put
     Prepayment Date.  Such offered prepayment shall be made at one hundred
     percent (100%) of the principal amount of such Notes, together with:

               (i) an amount equal to the Make-Whole Amount, if any, as of the
          Put Prepayment Date in respect of the principal amount of the Notes
          being so prepaid; and

               (ii) interest on such principal amount then being prepaid accrued
          to the Put Prepayment Date.

     Two (2) Business Days prior to the making of such prepayment, the Company
     shall deliver to each holder of Notes by facsimile transmission a
     certificate of a Senior Financial Officer specifying the details of the
     calculation of such Make-Whole Amount as of the specified prepayment date
     (including documentation supporting the determination of the Make-Whole
     Discount Rate).

                                Attachment A-1
<PAGE>
 
          (C) OFFICER'S CERTIFICATE.  Each offer to prepay the Notes pursuant to
     this Section 4.6 shall be accompanied by a certificate, executed by a
     Senior Officer of the Company and dated the date of such offer, specifying:

               (i)  the Put Prepayment Date;

               (ii) that such offer is being made under Section 4.6 of this
          Agreement;

               (iii)  the principal amount of each Note offered to be prepaid;

               (iv) the interest that would be due on the Put Prepayment Date on
          each such Note offered to be prepaid;

               (v) that the conditions of this Section 4.6 have been fulfilled;
          and

               (vi) a reasonably detailed calculation of an estimated Make-Whole
          Amount, if any (calculated as if the date of such notice was the Put
          Prepayment Date), that would be due in connection with such offered
          prepayment.

          (D) EFFECT OF PREPAYMENT.  Each prepayment of the Notes pursuant to
     this Section 4.6 shall be applied to reduce each of the Required Principal
     Payments remaining after the date of such prepayment ratably.

          (E) NOTICE CONCERNING STATUS OF HOLDERS OF NOTES.  Promptly after the
     Put Prepayment Date and the making of all prepayments contemplated under
     this Section 4.6 (and, in any event, within ten (10) days thereafter), the
     Company shall deliver to each Noteholder a certificate signed by a Senior
     Financial Officer of the Company containing a list of the then current
     holders of Notes (together with their addresses) and setting forth as to
     each such Noteholder the outstanding principal amount of Notes held by such
     Noteholder at such time.

          (F) NOTICE CONCERNING INVESTMENT GRADE CONDITION.  The Company will,
     promptly following satisfaction of the Investment Grade Condition, and in
     any event within five (5) Business Days thereafter, deliver to each
     Noteholder a copy of a letter or other writing from both S&P and Moody's
     evidencing such satisfaction, which copy shall be certified as true and
     complete by a Senior Financial Officer of the Company."


(S)A.2. THE FIRST SENTENCE OF SECTION 5.1 OF THE EXISTING NOTE PURCHASE
        AGREEMENTS IS AMENDED BY REPLACING THE CROSS-REFERENCE TO SECTION 6.3
        WITH A CROSS-REFERENCE TO SECTION 6.27.

(S)A.3. THE FIRST SENTENCE OF SECTION 5.2(A) OF THE EXISTING NOTE PURCHASE
        AGREEMENTS IS AMENDED BY REPLACING THE CROSS-REFERENCE TO SECTION 6.3
        WITH A CROSS-REFERENCE TO SECTION 6.27.

                                Attachment A-2
<PAGE>
 
(S)A.4. SECTION 6 OF THE EXISTING NOTE PURCHASE AGREEMENTS IS AMENDED AND
        RESTATED IN ITS ENTIRETY TO READ AS FOLLOWS:

"6.  COVENANTS

     The Company covenants that on and after the Amendment No. 1 Effective Date
and so long as any of the Notes shall be outstanding:

     6.1   Corporate Existence.  Each of the Company and its Material
Subsidiaries will preserve and maintain its existence except for the dissolution
of any Material Subsidiaries whose assets are transferred to the Company or any
of its Subsidiaries or except as otherwise expressly permitted herein.

     6.2   Maintenance.  Each of the Company and its Material Subsidiaries will
maintain, preserve and keep its properties and equipment necessary to the proper
conduct of its business in reasonably good repair, working order and condition
(normal wear and tear excepted) and will from time to time make all reasonably
necessary repairs, renewals, replacements, additions and betterments thereto so
that at all times such properties and equipment are reasonably preserved and
maintained, in each case with such exceptions as are not, individually or in the
aggregate, likely to have a Material Adverse Effect; provided, however, that
nothing in this Section 6.2 shall prevent the Company or any Material Subsidiary
from discontinuing the operation or maintenance of any such properties or
equipment if such discontinuance is, in the judgment of the Company or any
Material Subsidiary, as applicable, desirable in the conduct of their
businesses.

     6.3   Taxes.  Each of the Company and its Subsidiaries will duly pay and
discharge all Taxes upon or against it or its properties before penalties accrue
thereon (or, if later, within ninety (90) days of becoming past due), unless and
to the extent that the same is being contested in good faith and by appropriate
proceedings and reserves have been established in conformity with GAAP.

     6.4   ERISA.  Each of the Company and its Subsidiaries will timely pay and
discharge all obligations and liabilities arising under ERISA or otherwise with
respect to each Plan of a character which if unpaid or unperformed might result
in the imposition of a material Lien against any properties or assets of the
Company or any Material Subsidiary and will promptly notify each Noteholder upon
an officer of the Company becoming aware thereof, of (i) the occurrence of any
reportable event (as defined in ERISA) relating to a Plan (other than a multi-
employer plan, as defined in ERISA, so long as the event thereunder is not
reasonably likely to have a Material Adverse Effect), other than any such event
with respect to which the PBGC has waived notice by regulation; (ii) receipt of
any notice from PBGC of its intention to seek termination of any Plan or
appointment of a trustee therefor; (iii) the Company's or any of its
Subsidiaries' intention to terminate or withdraw from any Plan if such
termination or withdrawal would result in liability under Title IV of ERISA; and
(iv) the receipt by the Company or any of its Subsidiaries of notice of the
occurrence of any event that is reasonably likely to result in the incurrence of
any liability (other than for benefits), fine or penalty to the Company and/or
to any of the Company's Subsidiaries that would be material to the Company and
its Subsidiaries, taken as a whole, or any plan amendment that is reasonably
likely to materially increase the contingent liability of the Company and its
Subsidiaries, taken as a whole, in connection with any post-retirement benefit
under a welfare plan (subject to ERISA).  The Company will also promptly notify
each Noteholder of (i) any material

                                Attachment A-3
<PAGE>
 
contributions to any Foreign Plan that have not been made by the required due
date for such contribution if such default is reasonably likely to have a
Material Adverse Effect; (ii) any Foreign Plan that is not funded to the extent
required by the law of the jurisdiction whose law governs such Foreign Plan
based on the actuarial assumptions reasonably used at any time if such
underfunding (together with any penalties likely to result) could reasonably be
expected to have a Material Adverse Effect, and (iii) any material change
anticipated to any Foreign Plan that is reasonably likely to have a Material
Adverse Effect.

     6.5   Burdensome Restrictions, Etc.  Promptly upon any officer of the
Company becoming aware thereof, the Company shall give to each Noteholder
written notice of (i) the adoption of any new requirement of law which is
reasonably likely to have a Material Adverse Effect, and (ii) the existence or
occurrence of any strike, slow down or work stoppage which is reasonably likely
to have a Material Adverse Effect.

     6.6   Insurance.  Each of the Company, its Material Subsidiaries and any
SPVs will maintain or cause to be maintained, with responsible insurance
companies, insurance against any loss or damage to all insurable property and
assets owned by it, such insurance to be of a character and in or in excess of
such amounts as are customarily maintained by companies similarly situated and
operating like property or assets (subject to self-insured retentions and
deductibles) and will (subject to self-insured retentions and deductibles)
maintain or cause to be maintained insurance with respect to employers' and
public and product liability risks.  The Company will within ten (10) Business
Days after the Initial Borrowing Date and on or before March 31st of each
calendar year and upon the request of any Noteholder, furnish a certificate from
an officer of the Company setting forth the nature and extent of the insurance
maintained pursuant to this Section 6.6.

     6.7   Financial Reports and Other Information.  (a)  The Company, its
Subsidiaries and any SPVs will maintain a system of accounting in such manner as
will enable preparation of financial statements in accordance with GAAP and will
furnish to the Noteholders and their respective authorized representatives such
information about the business and financial condition of the Company, its
Subsidiaries and any SPVs as any Noteholder may reasonably request; and, without
any request, will furnish to each Noteholder:

          (i) within sixty (60) days after the end of each of the first three
(3) fiscal quarters of each fiscal year of the Company, the consolidated balance
sheet of the Company and its Subsidiaries as at the end of such fiscal quarter
and the related consolidated statements of income and retained earnings and of
cash flows for such fiscal quarter and for the portion of the fiscal year ended
with the last day of such fiscal quarter, all of which shall be in reasonable
detail or in the form filed with the SEC, and certified by the chief financial
officer of the Company that they fairly present the financial condition of the
Company and its Subsidiaries as of the dates indicated and the results of their
operations and changes in their cash flows for the periods indicated and that
they have been prepared in accordance with GAAP, in each case, subject to normal
year-end audit adjustments and the omission of any footnotes as permitted by the
SEC (delivery to each Noteholder of a copy of the Company's Form 10-Q filed with
the SEC (without exhibits) in any event will satisfy the requirements of this
subsection subject to Section 6.7(b));

          (ii) within one hundred twenty (120) days after the end of each fiscal
year of the Company, the consolidated balance sheet of the Company and its
Subsidiaries as at the end of

                                Attachment A-4
<PAGE>
 
such fiscal year and the related consolidated statements of income and retained
earnings and of cash flows for such fiscal year and setting forth consolidated
comparative figures as of the end of and for the preceding fiscal year, audited
by an independent nationally-recognized accounting firm and in the form filed
with the SEC (delivery to each Noteholder of a copy of the Company's Form 10-K
filed with the SEC (without exhibits) in any event will satisfy the requirements
of this subsection subject to Section 6.7(b));

          (iii) commencing with fiscal year 1997, to the extent actually
prepared and approved by the Company's board of directors, a projection of
Company's consolidated balance sheet and consolidated income, retained earnings
and cash flows for its current fiscal year showing such projected budget for
each fiscal quarter of the Company ending during such year; and

          (iv) within ten (10) days after the sending or filing thereof, copies
of all financial statements, projections, documents and other communications
that the Company sends to its stockholders generally or files with the SEC or
any similar governmental authority (and is publicly available).

     (b) Each financial statement furnished to the Noteholders pursuant to
subsections (i) and (ii) of Section 6.7(a) shall be (i) accompanied by
additional information setting forth calculations excluding the effects of any
SPVs and containing such calculations for any SPVs as reasonably requested by
any Noteholder, and (ii) accompanied by (x) a written certificate signed by the
Company's chief financial officer (or other financial officer of the Company),
in his or her capacity as such, to the effect that no Default or Event of
Default then exists or, if any such Default or Event of Default exists as of the
date of such certificate, setting forth a description of such Default or Event
of Default and specifying the action, if any, taken by the Company to remedy the
same, and (y) a compliance certificate substantially similar in form to Exhibit
6.7 to the Existing Credit Agreement (but in the first paragraph thereof
referring to the Note Purchase Agreements instead of to the Credit Agreement,
and in the second paragraph thereof certifying to the Noteholders instead of to
the Lenders and other Persons referred to in such Exhibit, and with such other
changes as necessary and appropriate to conform to the requirements of this
Agreement) showing the Company's compliance with certain of the covenants set
forth herein.  Together with the financial statements required pursuant to
subsections (i) and (ii) of Section 6.7(a), the Company shall furnish to the
Noteholders a certificate of the chief financial officer of the Company
reporting all Transfers of assets effected by the Company and its Subsidiaries
during the fiscal year covered by such financial statements which were other
than in the ordinary course of business and involved asset net book values in
excess of $250,000 in any single transaction or related series of transactions,
including the net book value of such assets and the amounts received by the
Company and its Subsidiaries with respect to such Transfers, and such other
information regarding such transactions as any Noteholder may reasonably
request.

     (c) Promptly upon receipt thereof, the Company will provide each Noteholder
with a copy of each report or "management letter" submitted to the Company, any
of its Material Subsidiaries or any SPVs by its independent accountants or
auditors in connection with any annual, interim or special audit made by them of
the books and records of the Company, any of its Material Subsidiaries or any
SPVs.

                                Attachment A-5
<PAGE>
 
     (d) Promptly after any officer of the Company obtains knowledge of any of
the following, the Company will provide each Noteholder with written notice in
reasonable detail of:

          (i) any pending or threatened material Environmental Claim against the
Company, any of its Subsidiaries or any SPV or any property owned or operated by
the Company, any of its Subsidiaries or any SPV;

          (ii) any condition or occurrence on any property owned or operated by
the Company, any of its Subsidiaries or any SPV that results in material
noncompliance by the Company, any of its Subsidiaries or any SPV with any
Environmental Law; and

          (iii)  the taking of any material remedial action in response to the
actual or alleged presence of any Hazardous Material on any property owned or
operated by the Company, any of its Subsidiaries or any SPV other than in the
ordinary course of business.

     (e) The Company will promptly, and in any event within five (5) days, after
an officer of the Company has knowledge thereof, give written notice to each
Noteholder of: (i) the occurrence of any Default or Event of Default; (ii) any
litigation or governmental proceeding of the type described in Section B.4 of
Attachment B to Amendment No. 1; (iii) any circumstance that has had or
reasonably threatens a Material Adverse Effect; (iv) the occurrence of any event
which has resulted in a breach of, or is likely to result in a breach of,
Sections 6.23, 6.24 or 6.25; and (v) any notice received by it, any Subsidiary
or any SPV from the holder(s) of Indebtedness of the Company, any Subsidiary or
any SPV in an amount which, in the aggregate, exceeds $5,000,000, where such
notice states or claims the existence or occurrence of any default or event of
default with respect to such Indebtedness under the terms of any indenture, loan
or credit agreement, debenture, note, or other document evidencing or governing
such Indebtedness.

     (f) The Company will promptly, and in any event within five (5) days, after
execution or other effectiveness thereof, give (or cause to be given) written
notice to each Noteholder of any amendment, restatement or other modification
of, and of each waiver or consent relating to, and each release or termination
(whether relating to collateral or to effectiveness of any such agreement) with
respect to, any of the Security Documents.

     6.8   Inspection Rights.  Upon reasonable notice from any Noteholder, the
Company will permit such Noteholder (and such Persons as such Noteholder may
reasonably designate) during normal business hours at such entity's sole expense
unless a Default or Event of Default shall have occurred and be continuing, in
which event at the Company's expense, to visit and inspect any of the properties
of the Company, any of its Subsidiaries or any SPV, to examine all of their
books and records, to make copies and extracts therefrom, and to discuss their
respective affairs, finances and accounts with their respective officers and
independent public accountants (and by this provision the Company authorizes
such accountants to discuss with such Noteholder (and such Persons as such
Noteholder may reasonably designate) the affairs, finances and accounts of the
Company, its Subsidiaries and any SPVs), all as often, and to such extent, as
may be reasonably requested.  The chief financial officer of the Company and/or
his or her designee shall be afforded the opportunity to be present at any such
meeting of any Noteholder and such accountants. Each Noteholder agrees to use
reasonable efforts to minimize, to the extent practicable, the number of
separate requests it shall make to exercise its rights under this Section 6.8
and/or Section 6.7.

                                Attachment A-6
<PAGE>
 
     6.9   Conduct of Business.  Except as expressly permitted herein, the
Company, its Subsidiaries and any SPVs will not engage in any line of business
other than the (i) contract drilling business, (ii) any hydrocarbon exploration
services or hydrocarbon development services business, (iii) on and after the
Exchange Offer Consummation Date, any then existing business of Transocean or
any of its Subsidiaries or (iv) any related business (each a "Permitted
Business").

     6.10  [Intentionally Omitted.]

     6.11  New Subsidiaries.  The Company will cause each Subsidiary (other than
any Person that is already a Guarantor with respect to the payment obligations
under this Agreement and the Notes pursuant to a Subsidiary Guaranty) that
becomes a guarantor of any of the payment obligations of the Company under the
Credit Agreement or any other Credit Document (whether pursuant to Section 6.11
of the Credit Agreement or otherwise) to become a guarantor with respect to, and
jointly and severally liable with all other Guarantors for, all the obligations
under this Agreement and the Notes pursuant to a Subsidiary Guaranty not later
than the time at which such Subsidiary becomes such a guarantor of payment
obligations of the Company under the Credit Agreement or any other Credit
Document, any such guaranties to be substantially on the same terms as provided
in the Subsidiary Guaranties as in effect on the Amendment No. 1 Effective Date
(subject to amendments and waivers with respect thereto, and subject to releases
or terminations thereof, in accordance with the terms of the relevant Subsidiary
Guaranty or the terms of the Existing Intercreditor Agreement).  The Company
will cause the Noteholders to have the benefits of any pledges of stock of any
Subsidiary (whether pursuant to Section 6.11 of the Credit Agreement or
otherwise), and of any pledges of notes of any Subsidiary, for the benefit of
any of the lenders (as such) under the Credit Agreement, on substantially the
same terms as provided in the Stock Pledge Agreement or the Note Pledge
Agreement, as the case may be, as in effect on the Amendment No. 1 Effective
Date (subject to amendments and waivers with respect thereto, and subject to
releases or terminations thereof, in accordance with the terms of the relevant
stock pledge agreement or note pledge agreement, as the case may be, or the
terms of the Existing Intercreditor Agreement).

     6.12  Limitation on Certain Restrictions on Subsidiaries; Dividends;
Negative Pledges.

     (a) The Company and its Subsidiaries will not, directly or indirectly,
create or otherwise permit to exist or become effective any contractual
restriction on the ability of any Subsidiaries of the Company to (i) pay
dividends or make any other distributions on its capital stock, or any other
interest or participation in its profits, owned by the Company or pay any
Indebtedness owed to the Company, or (ii) make loans or advances to the Company,
except for (1) restrictions existing under or by reason of applicable law or the
Note Purchase Agreements or the Credit Agreement or the other Credit Documents
or any modifications of any thereof, (2) agreements as to formalities required
to declare or make a dividend or distribution or that require retention of
reasonable cash reserves for working capital purposes, (3) with respect to any
particular Subsidiary, any such restriction contained in any agreement for the
sale or disposition of all or substantially all of the capital stock or assets
of such Subsidiary or of any other Subsidiary that directly or indirectly
controls such Subsidiary or providing for obligations of the nature described
in the definition of the term "Non-recourse Debt," (4) prior to the Exchange
Offer Consummation Date, any such restriction contained in the SODI Credit
Facility, and (5) any restrictions (not otherwise permitted above) existing in
connection with any Person acquired by, or merged with or into, the Company 

                                Attachment A-7
<PAGE>
 
or any Subsidiary of the Company after the C.A. Effective Date, in which case
the Company shall either promptly cause the removal or release of any such
restrictions not otherwise permitted above or not advance the proceeds of any
loan under the Credit Agreement to the relevant Subsidiary even if otherwise
permitted by the Credit Agreement.

     (b) The Company may only redeem, purchase or otherwise acquire any shares
of its capital stock if capital stock of the Company is purchased (or the
purchase thereof funded) (i) for any Code Section 401(K) plan, Code Section 423
plan or Plan or Foreign Plan of the Company or any of its Subsidiaries, or (ii)
so long as the Consolidated Net Worth (after giving effect to such redemption,
purchase or acquisition) is at least equal to the minimum Consolidated Net Worth
then required under Section 6.25 plus $100,000,000; in each case so long as no
Default or Event of Default shall have occurred and be continuing or would occur
as a result of such redemption, purchase or acquisition.  The Company shall not,
and will not permit any Subsidiary to, make any deposit for any purpose
prohibited by this Section 6.12(b).  Nothing in this Section 6.12(b) shall (i)
prohibit the redemption, purchase or acquisition of capital stock of the Company
within sixty (60) days after the commitment to effect such redemption, purchase
or acquisition is made, if at the date such commitment is made, such redemption,
purchase or acquisition would have complied with this Section 6.12(b), (ii)
prohibit the making of any deposit for any redemption, purchase or acquisition
of capital stock of the Company, if at the date such deposit is made such
redemption, purchase or acquisition would have complied with this Section
6.12(b), or (iii) prohibit the payment of cash in lieu of fractional shares.

     (c) The Company and its Subsidiaries shall not enter into any agreement
expressly and directly (i) prohibiting the creation or assumption of any Lien
upon its properties, revenues or assets, whether now owned or hereafter
acquired, or (ii) prohibiting or restricting the ability of the Company or any
Subsidiary of the Company from amending or otherwise modifying this Agreement,
except that the Company or any Subsidiary of the Company may do so (x) in
connection with (1) the creation, incurrence or assumption of any Lien permitted
to exist pursuant to Section 6.14, (2) the incurrence or assumption of any
Indebtedness or letters of credit permitted to exist pursuant to Section 6.15 of
the Existing Credit Agreement or of any Non-recourse Debt or (3) a transaction
or proposed transaction pursuant to which the Notes would be prepaid in like
amount, (y) with respect to any particular property or asset (or the revenues
associated therewith), in connection with any permitted transaction involving
such property or asset (including, without limitation, prohibitions in
agreements on the assignment or granting of a Lien thereon) or the Subsidiary of
the Company owning such property or asset, or (z) in, or in any modification of,
the Note Purchase Agreements, the Credit Agreement or any of the Credit
Documents.

     6.13  Restrictions on Fundamental Changes.  Neither the Company nor any of
its Subsidiaries shall be a party to any merger into or consolidation with, or
purchase or otherwise acquire all or substantially all of the assets or stock of
any other Person, or sell all or substantially all of its assets or stock
except:

     (a) the Exchange Offer, any subsequent acquisition of the stock of
Transocean, and any transfer of stock in Transocean by the Company to NSub;

     (b) the Company or any of its Subsidiaries may form new Subsidiaries;

                                Attachment A-8
<PAGE>
 
     (c) the Company or any of its Subsidiaries may merge into, or consolidate
with, or purchase or otherwise acquire all or substantially all of the assets or
stock of any other Person if upon the consummation of any such merger,
consolidation, purchase or acquisition, (i) the Company or such Subsidiary is
the surviving corporation to any such merger or consolidation (or the other
Person is, or will thereby become, a Subsidiary of the Company), (ii) the
Company or any such Subsidiary complies with Section 6.11 and Section 6.12 to
the extent applicable and (iii) no Event of Default shall have occurred and be
continuing or would otherwise be existing as a result of such merger,
consolidation, purchase or acquisition;

     (d) the Company may purchase or otherwise acquire all or substantially all
of the stock or assets of, or otherwise acquire by merger or consolidation, any
Subsidiary; and any of the Company's Subsidiaries may merge into, or consolidate
with, or purchase or otherwise acquire all or substantially all of the assets or
stock of or sell all or substantially all of their assets or stock to, any other
Subsidiary of the Company (or to a Person who will contemporaneously therewith
become a Subsidiary of the Company) and the Company may sell all or
substantially all of the stock of any Subsidiary of the Company to any other
Subsidiary of the Company (or to a Person who will contemporaneously therewith
become a Subsidiary of the Company), so long as (i) Section 6.11 and Section
6.12 are complied with to the extent applicable and (ii) no Default or Event of
Default shall have occurred and be continuing or would otherwise be existing
after or result from such merger, consolidation, purchase or acquisition;

     (e) any Transfer (including any Transfer of the stock of a Subsidiary of
the Company) permitted under Section 6.19, and any merger or consolidation
involving any Subsidiary of the Company which, if treated as a Transfer of the
assets of such Subsidiary, would be permitted under Section 6.19; and

     (f) the Company and its Subsidiaries may issue additional capital stock or
ownership interests so long as there is no scheduled mandatory redemption or
scheduled liquidating distribution of any such stock or interest before the
Maturity Date.  The Company shall not take any action which will result in a
decrease in the percentage of the outstanding shares of capital stock which it
owns in NSub or any other direct Material Subsidiary, and will not permit NSub
to take any action which will result in a decrease in the percentage of the
outstanding shares of capital stock which NSub owns in Transocean.  The Company
or any Subsidiary of the Company may decrease its ownership percentage of any
other Material Subsidiary (i) so long as (x) the Company, directly or
indirectly, maintains an ownership interest of at least fifty-one percent (51%)
and has voting control of the Board of Directors or similar governing body in
such Material Subsidiary or (y) its entire ownership interest in such Material
Subsidiary is transferred pursuant to the terms hereof, or (ii) in connection
with any dissolution of such Material Subsidiary permitted by Section 6.1 or any
other transaction expressly permitted herein.

     6.14  Liens.  The Company and its Subsidiaries shall not create, incur,
assume or suffer to exist any Lien of any kind on any property or asset of any
kind of the Company or any Subsidiary, except the following (collectively, the
"Permitted Liens"):

     (a) Liens arising in the ordinary course of business by operation of law,
deposits, pledges or other Liens in connection with workers' compensation,
unemployment insurance, old age benefits, social security obligations, taxes,
assessments, public or statutory obligations or other

                                Attachment A-9
<PAGE>
 
similar charges, good faith deposits, pledges or other Liens in connection with
(or to obtain letters of credit in connection with) bids, performance, return-
of-money or payment bonds, contracts or leases to which the Company or its
Subsidiaries are parties or other deposits required to be made in the ordinary
course of business; provided that in each case the obligation secured is not for
Indebtedness for borrowed money and is not overdue or, if overdue, is being
contested in good faith by appropriate proceedings and reserves in conformity
with GAAP have been provided therefor;

     (b) mechanics', workmen's, materialmen's, landlords', carriers' or other
similar Liens arising in the ordinary course of business (or deposits to obtain
the release of such Liens) related to obligations not overdue for more than
thirty (30) days if such Liens arise with respect to domestic assets and for
more than ninety (90) days if such Liens arise with respect to foreign assets,
or, if so overdue, that are being contested in good faith by appropriate
proceedings and reserves in conformity with GAAP have been provided therefor;

     (c) Liens for Taxes not more than ninety (90) days past due or which can
thereafter be paid without penalty or which are being contested in good faith by
appropriate proceedings and reserves in conformity with GAAP have been provided
therefor;

     (d) Liens imposed by ERISA (or comparable foreign laws) which are being
contested in good faith by appropriate proceedings and reserves in conformity
with GAAP have been provided therefor;

     (e) Liens arising out of judgments or awards against the Company or any of
its Subsidiaries, or in connection with surety or appeal bonds or the like in
connection with bonding such judgments or awards, the time for appeal from which
or petition for rehearing of which shall not have expired or for which the
Company or such Subsidiary shall be prosecuting on appeal or proceeding for
review, and for which it shall have obtained (within thirty (30) days with
respect to a judgment or award rendered in the United States or within sixty
(60) days with respect to a judgment or award rendered in a foreign jurisdiction
after entry of such judgment or award or expiration of any previous such stay,
as applicable) a stay of execution or the like pending such appeal or proceeding
for review; provided, that the aggregate amount of uninsured or underinsured
liabilities (including interest, costs, fees and penalties, if any) of the
Company and its Subsidiaries secured by such Liens shall not exceed $15,000,000
at any one time outstanding;

     (f) Liens securing Indebtedness permitted by Section 6.15(d) or (e) of the
Existing Credit Agreement (or on repairs, renewals, replacements, additions,
accessions and betterments thereto);

     (g) (i) Liens on assets and interests acquired after the C.A. Effective
Date, and Liens on the Amaranti and the Discoverer Enterprise, in each case so
long as such Liens secure "Non-recourse Debt", and (ii) Liens on the stock or
assets of SPVs;

     (h) Liens on property existing at the time such property is acquired by the
Company or any Subsidiary of the Company and not created in contemplation of
such acquisition (or on repairs, renewals, replacements, additions, accessions
and betterments thereto) and Liens on the assets of any Person at the time such
Person becomes a Subsidiary of the Company and not created in

                                Attachment A-10
<PAGE>
 
contemplation of such Person becoming a Subsidiary of the Company (or on
repairs, renewals, replacements, additions, accessions and betterments thereto),
provided that the aggregate amount of Indebtedness secured by all such Liens
(including, without limitation, any such Liens as the same may be extended,
renewed or replaced pursuant to clause (j) below) does not exceed $30,000,000 at
any one time outstanding;

     (i) Liens existing on the C.A. Effective Date and listed on Schedule 6.14
to the Existing Credit Agreement;

     (j) any extension, renewal or replacement (or successive extensions,
renewals or replacements) in whole or in part of any Lien referred to in the
foregoing subsections (a) through (i), provided, however, that the principal
amount of Indebtedness secured thereby does not exceed the principal amount
secured at the time of such extension, renewal or replacement, and that such
extension, renewal or replacement is limited to the property already subject to
the Lien so extended, renewed or replaced;

     (k) rights reserved to or vested in any municipality or governmental,
statutory or public authority by the terms of any right, power, franchise,
grant, license or permit, or by any provision of law, to terminate such right,
power, franchise, grant, license or permit or to purchase, condemn, expropriate
or recapture or to designate a purchaser of any of the property of a Person;

     (l) rights reserved to or vested in any municipality or governmental,
statutory or public authority to control, regulate or use any property of a
Person;

     (m) rights of a common owner of any interest in property held by a Person
and such common owner as tenants in common or through other common ownership;

     (n) encumbrances (other than to secure the payment of Indebtedness),
easements, restrictions, servitudes, permits, conditions, covenants, exceptions
or reservations in any property or rights-of-way of a Person for the purpose of
roads, pipelines, transmission lines, transportation lines, distribution lines,
removal of gas, oil, coal, metals, steam, minerals, timber or other natural
resources, and other like purposes, or for the joint or common use of real
property, rights-of-way, facilities or equipment, or defects, irregularity and
deficiencies in title of any property or rights-of-way;

     (o) zoning, planning and environmental laws and ordinances and municipal
regulations;

     (p) financing statements filed by lessors of property (but only with
respect to the property so leased);

     (q) Liens created, or required or contemplated to be created, by or under
the Security Documents or Section 6.10, 6.11 or 7.4 of the Existing Credit
Agreement;

     (r) Liens on properties or assets, such as (without limitation) contracts
and books and records, directly relating to any properties or assets subject to
a Lien otherwise permitted by this Section 6.14;

                                Attachment A-11
<PAGE>
 
     (s) Liens on rents, revenues and other income associated with, or other
proceeds of, any properties or assets subject to a Lien permitted under this
Section 6.14;

     (t) Liens to secure the SODI Credit Facility or the Transocean Credit
Facility until such time as the Indebtedness thereunder is required to be paid
pursuant to the terms hereof;

     (u) Liens on up to $4,900,000 in cash (or any investments thereof) to
secure performance by Transocean and/or its Subsidiaries of their obligations in
respect of the guarantee issued to Nissho Iwai by Christiania Bank og
Kreditkasse under Reference No. 250,115 dated 24 September 1986;

     (v) Liens on cash in an aggregate amount no greater than the aggregate cash
purchase price offered for the shares of Transocean stock in the Mandatory Bid
(together with interest thereon as required under Norwegian law or by the Oslo
Stock Exchange), deposited with the bank issuing any Mandatory Bid Bank
Guarantee or any other reasonably necessary Person for the purpose of
discharging the Company's or NSub's obligations under the Mandatory Bid (or any
investments thereof); and

     (w) Liens (not otherwise permitted by this Section 6.14) on property
securing Indebtedness (or other obligations) aggregating at any time outstanding
no greater than $5,000,000.

     6.15  [Intentionally Omitted.]

     6.16  Use of Property and Facilities; Environmental Laws.  The Company and
its Subsidiaries shall comply in all material respects with all Environmental
Laws applicable to or affecting the properties or business operations of the
Company or any Subsidiary of the Company, where the failure to comply is
reasonably likely to have a Material Adverse Effect.

     6.17  Advances, Investments and Loans.  The Company and its Subsidiaries
shall not lend money or make advances to any Person, or purchase or acquire any
stock, indebtedness, obligations or securities of, or any other interest in, or
make any capital contribution to, any other Person (any of the foregoing, an
"Investment") except:

     (a) Investments in Cash Equivalents and deposit accounts;

     (b) receivables owing to the Company or a Subsidiary of the Company created
or acquired in the ordinary course of business and payable on customary trade
terms of the Company or such Subsidiary;

     (c) Investments 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;

     (d) Interest Rate Protection Agreements and foreign exchange futures
agreements, arrangements or options entered into in compliance with Section
6.15(g) or 6.15(h) of the Existing Credit Agreement;

                                Attachment A-12
<PAGE>
 
     (e) deposits and progress payments made in the ordinary course of business;

     (f) any Investment by the Company or any Subsidiary of the Company in the
Company, any Subsidiary of the Company or any Person that, upon such Investment,
will become a Subsidiary of the Company or will be merged with or into the
Company or any Subsidiary of the Company and any Guaranties with respect thereto
except as expressly restricted hereunder;

     (g) as permitted by Section 6.12 or 6.13;

     (h) Investments of substantially equivalent quality to those referred to in
subsections (i), (ii), and (iii) of the definition of Cash Equivalents
denominated in a currency other than Dollars, provided that the aggregate net
book value of all such investments under this Section 6.17(h) shall not exceed
an amount equal to five percent (5%) of Consolidated Tangible Assets at any time
outstanding;

     (i) Investments existing on the C.A. Effective Date and referred to on
Schedule 6.17 to the Existing Credit Agreement;

     (j) travel, relocation, sales commission and other advances to, and loans
to, officers and employees incurred or made in the ordinary course of business;

     (k) Investments in another Person received in connection with the
disposition of assets by the Company or any Subsidiary of the Company not
prohibited herein;

     (l) to the extent (if any) constituting Investments, obligations of other
Persons to the Company or any of its Subsidiaries in respect of the existence or
performance of Performance Guaranties, Performance Letters of Credit (or related
reimbursement obligations) or Indebtedness described in Section 6.15(l) of the
Existing Credit Agreement;

     (m) Investments in SPVs and other Persons, including, without limitation,
by means of advances or loans to another Person who has a direct or indirect
investment in a Subsidiary of the Company or a SPV, provided that (i) such SPV
or such other Person is engaged in a Permitted Business, and (ii) an investment
shall not be permitted under this Section 6.17(m) if at the time it is made and
after giving effect thereto the aggregate net book value of all such Investments
under this Section 6.17(m) shall exceed twenty-five percent (25%) of
Consolidated Tangible Assets determined at such time; and (iii) no drillships,
offshore mobile drilling units or offshore drilling rigs owned as of the C.A.
Effective Date by the Company or any of its Subsidiaries (or from and after the
Exchange Offer Consummation Date, Transocean or any of its Subsidiaries) are
transferred to any such entity pursuant to this Section 6.17(m) (excluding the
Amaranti and the Discoverer Enterprise);

     (n) temporary Investments of cash not otherwise permitted above to the
extent the same is being held to fund reasonably anticipated working capital
needs, not to exceed the equivalent of $5,000,000 in the aggregate;

                                Attachment A-13
<PAGE>
 
     (o) Investments in obligations of a state of the United States of America
or any state or other political subdivision thereof given a rating of A or
better by S&P or Moody's and maturing within one (1) year from the date of
acquisition;

     (p) Investments in any variable-dividend rate preferred stock issued by a
closed-ended investment company regulated under the Investment Company Act of
1940, as amended, which invests solely in obligations of any state of the United
States of America or any state or other political subdivision thereof that at
the time of the making of such Investment has the highest ratings by S&P or
Moody's (or the highest rating by another U.S. nationally recognized rating
agency) the dividend rate of which preferred stock is reset no less frequently
than each thirty (30) days;

     (q) Investments in shares of investment companies regulated under the
Investment Company Act of 1940, as amended, provided that such companies invest
primarily in investments of the types described in the definition of Cash
Equivalents;

     (r) other Investments received by way of dividend, distribution or
mandatory exchange or conversion in respect of any of the foregoing;

     (s) consummation of the Exchange Offer; and

     (t) Investments not otherwise permitted by this Section 6.17 having an
aggregate net book value at any time outstanding not in excess of $5,000,000.

     6.18  Modifications of Corporate Documents.  Neither the Company nor any of
its Subsidiaries shall amend, modify or change in any way materially adverse to
the interests of the Noteholders, its certificate or articles of incorporation
or by-laws or (in the case of persons other than corporations) other comparable
corporate governance documents, it being acknowledged and agreed that the
amendments to the Company's certificate of incorporation described in the Offer
to Purchase (as delivered to each Noteholder) do not violate this Section 6.18.

     6.19  Transfers of Assets.  The Company and its Subsidiaries shall not
permit any Transfer of an asset except:

     (a) the Transfer of inventory, equipment and other assets in the ordinary
course of business;

     (b) the retirement or replacement of assets in the ordinary course of
business;

     (c) the Transfer of any assets among any of the Company and its
Subsidiaries;

     (d) any Transfer permitted by Section 6.12;

     (e) any Transfer permitted by Section 6.13;

     (f) any Investment permitted by Section 6.17;

                                Attachment A-14
<PAGE>
 
     (g) the Liens permitted by Section 6.14;

     (h) sale and leaseback transactions, provided that the aggregate amount
that would be reflected as a liability on the balance sheet of the Company if
such transactions were treated as Capitalized Lease Obligations shall not exceed
$35,000,000 at any one time;

     (i) the Transfer of assets that are obsolete, worn out or no longer useful
in the business of the Company or the relevant Subsidiary of the Company, as the
case may be;

     (j) the Transfer of any Investment in a SPV or any Person other than a
Subsidiary of the Company;

     (k) exchanges of assets that are of a like kind and value; and

     (l) the Transfer of any assets not otherwise covered by this Section 6.19,
provided that (i) the net book value of such assets shall not exceed in the
aggregate $25,000,000 for fiscal year 1996, and (ii) for each fiscal year
thereafter, the net book value of such assets shall not exceed five percent (5%)
of Total Assets as of the last day of the preceding fiscal year and the annual
contribution to EBIT of such assets shall not exceed in the aggregate ten
percent (10%) of EBIT for the preceding fiscal year (or, for fiscal year 1997,
pro forma EBIT for fiscal year 1996), in each case determined in accordance with
GAAP.

     6.20  Transactions with Affiliates.  Except as otherwise specifically
permitted herein, the Company and its Subsidiaries shall not (except pursuant to
contracts outstanding as of (i) with respect to the Company, the C.A. Effective
Date or (ii) with respect to any Subsidiary of the Company, the C.A. Effective
Date or, if later, the date such Subsidiary first became a Subsidiary of the
Company) enter into or engage in any material transaction or arrangement or
series of related transactions or arrangements which in the aggregate would be
material with any Controlling Affiliate, including without limitation, the
purchase from, sale to or exchange of property with, any merger or consolidation
with or into, or the rendering of any service by or for, any Controlling
Affiliate, except pursuant to the requirements of the Company's or such
Subsidiary's business and unless such transaction or arrangement or series of
related transactions or arrangements, taken as a whole, is fair and equitable to
the Company or such Subsidiary.

     6.21  Optional Prepayments.  Neither the Company nor any Subsidiary of the
Company shall, directly or indirectly, optionally prepay, purchase, redeem,
retire, defease or otherwise acquire, or make any optional payment on account of
any principal of, interest on, or premium payable in connection with the
optional prepayment, redemption or retirement of, any of its Indebtedness (other
than Indebtedness evidenced by the Notes and the Note Purchase Agreements and
Indebtedness to the Company or any Subsidiary of the Company), or give an
optional notice of redemption with respect to any such Indebtedness, in each
case if any Default or Event of Default shall have occurred and be continuing
hereunder (after giving effect to any such optional payment).

     6.22  Compliance with Laws.  Without limiting any of the other covenants of
the Company in this Section 6, the Company and its Subsidiaries shall conduct
their business, and otherwise be, in compliance with all applicable laws,
regulations, ordinances and orders of any governmental or 

                                Attachment A-15
<PAGE>
 
judicial authorities; provided, however, that this Section 6.22 shall not
require the Company or any Subsidiary of the Company to comply with any such
law, regulation, ordinance or order if (x) it shall be contesting such law,
regulation, ordinance or order in good faith by appropriate proceedings and
reserves in conformity with GAAP have been provided therefor, or (y) the failure
to comply therewith is not reasonably likely to have a Material Adverse Effect.

     6.23  Interest Coverage Ratio.  The Company will not permit the Interest
Coverage Ratio as of the end of each fiscal quarter of the Company, commencing
with the first full fiscal quarter ended after the Exchange Offer Consummation
Date, to be less than 3:00 to 1:00.

     6.24  Total Funded Debt to Total Capital Ratio.  The Company will maintain,
as of the end of each fiscal quarter of the Company, commencing with the first
full fiscal quarter ended after the Exchange Offer Consummation Date, a ratio
(expressed as a percentage) of Total Funded Debt to Total Capital of (i) no
greater than 45% during the period from the first day of such first full fiscal
quarter through December 31, 1998, and (ii) at any time from January 1, 1999,
until final maturity, no greater than 40%.

     6.25  Minimum Consolidated Net Worth.  The Company will (i) maintain, for
the period from immediately after the Exchange Offer Consummation Date through
the consummation of the Mandatory Bid, a minimum Consolidated Net Worth of at
least ninety percent (90%) of Consolidated Net Worth as of immediately after the
Exchange Offer Consummation Date, and will have a Consolidated Net Worth of at
least $1,400,000,000 as of immediately after the consummation of the Mandatory
Bid, and (ii) maintain a minimum Consolidated Net Worth, as of the end of each
full fiscal quarter of the Company after the Exchange Offer Consummation Date,
of at least the sum of (x) $1,400,000,000, plus (y) an amount equal to 50% of
Consolidated Adjusted Net Income (if positive) for the fiscal quarter ending
December 31, 1996, plus (z) an amount equal to the greater of 0 and 50% of
fiscal year-to-date Consolidated Adjusted Net Income (if positive) for each
fiscal quarter thereafter.

     6.26  SODI Credit Facility and Transocean Credit Facility Releases.  The
Company will provide to each Noteholder evidence that the promissory notes and
all other outstanding Indebtedness under the SODI Credit Facility and the
Transocean Credit Facility have been paid in full and evidence that all Liens
under the SODI Credit Facility and the Transocean Credit Facility have been
released within one (1) day of the Initial Borrowing Date with respect to the
SODI Credit Facility and within eleven (11) days of the Initial Borrowing Date
with respect to the Transocean Credit Facility.

     6.27  Payment of Notes and Maintenance of Office.  The Company will
punctually pay, or cause to be paid, the principal of and interest (and Make-
Whole Amount, if any) on, the Notes, as and when the same shall become due
according to the terms hereof and of the Notes, and will maintain an office at
the address of the Company referred to in Section 10.1 hereof where notices,
presentations and demands in respect hereof or the Notes may be made upon it.
Such office will be maintained at such address until such time as the Company
shall notify the holders of the Notes of any change of location of such office,
which will in any event be located within the United States of America.

                                Attachment A-16
<PAGE>
 
     6.28 Private Offering. The Company will not, and will not authorize any
Person to, offer the Notes or any part thereof or any similar Securities for
issue or sale to, or solicit any offer to acquire any of the same from, any
Person so as to require registration of the issuance and sale of the Notes under
section 5 of the Securities Act.

     6.29  Equal and Ratable Lien; Equitable Lien.  In case any property or
asset shall be subjected to a Lien in violation of Section 6.14, the Company
will forthwith make or cause to be made, to the fullest extent permitted by
applicable law, provision whereby the Notes will be secured equally and ratably
with all other obligations secured thereby pursuant to such agreements and
instruments as shall be approved by the Required Holders, and the Company will,
if so requested by the Required Holders, promptly cause to be delivered to each
holder of a Note an opinion of independent counsel satisfactory to the Required
Holders to the effect that such agreements and instruments have been duly
authorized, executed and delivered and are enforceable in accordance with their
terms, and in any such case the Notes shall have the benefit, to the full extent
that, and with such priority as, the holders of Notes may be entitled under
applicable law, of an equitable Lien on such Property (and any proceeds thereof)
securing the Notes.  Such violation of Section 6.14 will constitute a Default
hereunder, whether or not any such provision is made pursuant to this Section
6.29.

     6.30  Fees, etc. in Connection with Releases, etc.  If the Company at any
time directly or indirectly pays any fee (or other similar monetary
compensation, however effected) (collectively, "FEES") to the agent, or any of
the lenders, under the Credit Agreement, or to the Collateral Agent, in either
case as an inducement for, or otherwise in consideration for, any release or
other termination of, or any consent to the release or termination of, any of
the Common Collateral (as such term is defined in the Existing Intercreditor
Agreement), then the Company will contemporaneously pay a Fee, as the case may
be, ratably (based on the principal amount of each Note then outstanding) to the
Noteholders in an aggregate amount not less than "X," where "X" is an amount
that bears the same proportion to the aggregate amount of such Fees paid to the
agent and/or any of the lenders under the Credit Agreement and/or to the
Collateral Agent as the then outstanding principal amount of the Notes bears to
the then outstanding principal amount of Indebtedness under the Credit
Agreement.  Notwithstanding the foregoing, Fees shall not be deemed to include
(a) any repayment or prepayment of loans (or interest thereon), or any payment
of obligations in respect of letters of credit, under the Credit Agreement, (b)
any payment of breakage fees of the type referred to in Section 2.13 of the
Existing Credit Agreement or (c) any payment of out-of-pocket costs or expenses
(including, without limitation, attorneys' fees and expenses) incurred by the
agent or any of the lenders under the Credit Agreement, or by the Collateral
Agent.

     6.31  Most Favored.

          (a) If at any time after the Amendment No. 1 Effective Date the
Company shall enter into, be or become a party to, or otherwise be or become
bound by, the provisions of (i) any amendment to or other modification of the
Existing Credit Agreement (disregarding any portion of any such amendment or
other modification that (I) is required or contemplated to be entered into
pursuant to the terms of SECTION 6 of the Existing Credit Agreement or the terms
of any Existing Credit Document or (II) makes any Restrictive Covenant less
onerous to the Company) or (ii) any credit agreement, loan agreement, indenture,
note purchase agreement, note, debenture or other 

                                Attachment A-17
<PAGE>
 
instrument or agreement, in each case described in this clause (ii) (x) other
than the Financing Documents, the Existing Credit Agreement, any Existing Credit
Document, the SODI Credit Facility or any amendment or modification of any
thereof to the extent satisfying either of the conditions set forth in
subclauses (I) and (II) of the parenthetical phrase in the foregoing clause (i),
and (y) under or in connection with which Institutional Funded Indebtedness has
been issued or is otherwise outstanding ((i) or (ii), an "INDEBTEDNESS
DOCUMENT"), and any such Indebtedness Document contains or otherwise provides
for (whether by incorporation by reference or otherwise) one or more Restrictive
Covenants that are more onerous to the Company, or that are more favorable to
the lenders or other creditors under such Indebtedness Document, than the
corresponding or otherwise comparable Restrictive Covenants, if any, provided
for in this Agreement, or with respect to which there are no corresponding or
otherwise comparable Restrictive Covenants provided for in this Agreement (such
more onerous to the Company, or such more favorable to the lenders or other
creditors under such Indebtedness Document, Restrictive Covenants in such
Indebtedness Document, if any, and including, without limitation, any
Restrictive Covenants in such Indebtedness Document that do not correspond, or
otherwise are not comparable, to any Restrictive Covenants in this Agreement,
the "OTHER INDEBTEDNESS MORE ONEROUS RESTRICTIVE COVENANTS"; such corresponding
or other comparable Restrictive Covenants set forth in the Note Purchase
Agreements, if any, the "NPA CORRESPONDING RESTRICTIVE COVENANTS"), then the
Company shall promptly (and in any event within five (5) Business Days) provide
written notice of such fact to each Noteholder, which notice shall be
accompanied by a copy of such Indebtedness Document. The Company agrees, if
requested in writing by the Required Holders within ninety (90) days of receipt
by the Noteholders of such notice, to enter into one or more amendments of the
Note Purchase Agreements providing for substantially the same Other Indebtedness
More Onerous Restrictive Covenants as those provided for in such Indebtedness
Document (with such modifications thereof, and of the NPA Corresponding
Restrictive Covenants, if any, as may be necessary to give the Noteholders
substantially the same (but not more favorable to such Noteholders) benefits and
protections (taking into account not only such Other Indebtedness More Onerous
Restrictive Covenants but also any NPA Corresponding Restrictive Covenants)
afforded the lenders or creditors under such Indebtedness Document by virtue of
such Other Indebtedness More Onerous Restrictive Covenants). Any such amendments
to the Note Purchase Agreements shall, if requested in writing by the Required
Holders, be deemed to be effective retroactively to the time the related Other
Indebtedness More Onerous Restrictive Covenants became effective under such
Indebtedness Document.

          (b) As used in this Agreement, the term "INSTITUTIONAL FUNDED
INDEBTEDNESS" means indebtedness (whether or not secured, but subject to the
second sentence of this subsection (b)) of (or Guarantied by) the Company for
borrowed money or evidenced by bonds, notes, debentures, or other similar
instruments (x) that at the date such indebtedness originally is incurred,
created or issued, as the case may be, (1) is scheduled to mature more than
twelve (12) months later and (2) is primarily owed to one or more banks,
insurance companies or other financial institutions, and (y) the original
principal amount of which is in excess of $5,000,000.  Notwithstanding the
foregoing, Institutional Funded Indebtedness shall not include secured
indebtedness of the Company (or of any other Person (including, without
limitation, any SPV) Guarantied by the Company) of the nature described in
Section 6.14(f), (g), (h) or (insofar as said subsection relates to Section
6.14(f), (g) or (h)), (j) of this Agreement.

                                Attachment A-18
<PAGE>
 
          (c) As used in this Agreement, the term "RESTRICTIVE COVENANTS" means
covenants of the Company of the general or specific nature of the covenants of
the Company set forth in Section 6 hereof and (subject to the second sentence of
this subsection (c)) events of default of the general or specific nature set
forth in Section 8.1 hereof, or other restrictive covenants of the Company
(including, without limitation, any such covenants measuring, or in effect
measuring, financial performance, or any balance sheet condition or similar
condition, of the Company or any of its Subsidiaries or SPVs), but in any event
excluding (i) indebtedness payment or prepayment terms (other than events of
default and acceleration provisions to the extent, if any, otherwise covered by
this subsection (c)) and terms concerning the payment of interest and (ii) the
covenant set forth in Section 6.15 of the Existing Credit Agreement and any
other substantially identical covenant (or covenant covering all or a portion of
substantially the same subject matter as, but in a manner that is less onerous
to the Company than (and does not include any provisions that are more onerous
to the Company than), Section 6.15 of the Existing Credit Agreement) agreed to
by the Company in any other Indebtedness Document. The foregoing references in
this subsection (c) to events of default shall be deemed to include all events
of default under the Credit Agreement, but shall be deemed to exclude events of
default under any other Indebtedness Document unless such events of default are
of a nature that customarily would be expressed in Institutional Funded
Indebtedness Indebtedness Documents as covenants as opposed to events of
default. The foregoing references in this subsection (c) to covenants and events
of default shall be deemed to include any defined terms as and to the extent
used in such covenants and events of default.


(S)A.5. SECTION 7 OF THE EXISTING NOTE PURCHASE AGREEMENTS IS AMENDED AND
        RESTATED IN ITS ENTIRETY TO READ AS FOLLOWS:

"7.  CONFIDENTIALITY

     Any information concerning the Company or any Subsidiary that has been
supplied to any holder of Notes by the Company or such Subsidiary and identified
in writing by such party as confidential and that is not, at the time supplied
to such holder or thereafter, information available to the public, shall be
treated as confidential by such holder in accordance with the procedures and
standards that such holder generally applies to information of a confidential
nature (and shall not, in any event, be delivered by such holder to any
Competitor). Notwithstanding the foregoing, the Company acknowledges that the
holder of any Note may deliver copies of any financial statements and other
documents delivered to such holder, and disclose any other information disclosed
to such holder, by or on behalf of the Company or any Subsidiary in connection
with or pursuant to this Agreement to

          (a) such holder's directors, officers, employees, agents and
     professional consultants,

          (b)  any other holder of any Note,

          (c) any Person to which such holder offers to sell such Note or any
     part thereof, provided that such Person first agrees in writing for the
     benefit of the Company to be subject to the requirements of this Section,

                                Attachment A-19
<PAGE>
 
          (d) any federal or state regulatory authority having jurisdiction over
     such holder, and the National Association of Insurance Commissioners or any
     similar organization,

          (e) Standard & Poor's Corporation, Moody's Investor Services, Inc., or
     other nationally recognized financial rating service, which is reviewing
     the credit rating of any holder of Notes, and

          (f) any other Person to which such delivery or disclosure may be
     necessary or appropriate in compliance with any law, rule, regulation or
     order applicable to such holder, in response to any subpoena or other legal
     process, in connection with any litigation to which such holder is a party,
     or in order to protect such holder's investment in such Note."


(S)A.6. SECTION 8.1 OF THE EXISTING NOTE PURCHASE AGREEMENTS IS AMENDED AND
        RESTATED IN ITS ENTIRETY TO READ AS FOLLOWS:

"8.  EVENTS OF DEFAULT

     8.1   Events of Default.  Any one or more of the following shall constitute
an Event of Default:

     (a) default by the Company in the payment of the principal amount of any of
the Notes, any interest thereon or any Make-Whole Amount within two (2) Business
Days following the date when due;

     (b) default by the Company in the observance or performance of any covenant
set forth in Sections 6.7(e)(i) (if the Company shall have failed to give the
applicable written notice contemplated by Section 6.7(e)(i) within five (5) days
after a Senior Officer of the Company first having knowledge of the occurrence
of any Default or Event of Default), 6.12, 6.13, 6.19, 6.21, 6.23, 6.24, 6.25 or
6.26;

     (c) any event of default or default described in a Security Document other
than any Events of Default specifically provided in this Section 8.1 shall occur
and remain unremedied after any applicable grace period therefor, or if no grace
period is provided therein, the applicable grace period for purposes hereof
shall be thirty (30) days following notice to the Company by any Noteholder of
the occurrence of such event of default or default;

     (d) default by any Credit Party in the observance or performance of any
provision hereof or of any other Financing Document not mentioned in (a), (b) or
(c) above, which is not remedied within thirty (30) days after the earlier of
(i) such default first becoming known to any Senior Officer of the Company or
(ii) notice to the Company by any Noteholder of the occurrence of such default;

     (e) any representation or warranty or other written statement made or
deemed made herein or in any other Financing Document, or in any financial or
other report or instrument or other written statement furnished in compliance
herewith or therewith or in reference hereto or thereto, by the Company or any
Subsidiary proves untrue in any material respect as of the date of the making,
or deemed making, thereof;

                                Attachment A-20
<PAGE>
 
     (f) default occurs in the payment when due of Indebtedness or default
occurs in the payment, after any demand therefor, under a Performance Guaranty,
in an aggregate principal amount of $5,000,000 or more when aggregated with any
Indebtedness described in Section 8.1(l) which is then in default, of the
Company or any Subsidiary of the Company after any applicable grace period
therefor, and such default, if in payment when due of Indebtedness, continues
for a period of time sufficient to permit the holder or beneficiary of such
Indebtedness, or a trustee therefor, to cause the acceleration of the maturity
of any such Indebtedness or any mandatory unscheduled prepayment, purchase, or
other early funding thereof;

     (g) the Company or any Material Subsidiary (i) has entered involuntarily
against it an order for relief under the United States Bankruptcy Code or a
comparable action is taken under any bankruptcy or insolvency law of another
country or political subdivision of such country, (ii) generally does not pay,
or admits its inability generally to pay, its debts as they become due, (iii)
makes a general assignment for the benefit of creditors, (iv) applies for,
seeks, consents to, or acquiesces in, the appointment of a receiver, custodian,
trustee, liquidator or similar official for it or any substantial part of its
property under the United States Bankruptcy Code or under the bankruptcy or
insolvency laws of another country or a political subdivision of such country,
(v) institutes any proceeding seeking to have entered against it an order for
relief under the United States Bankruptcy Code or any comparable law, to
adjudicate it insolvent, or seeking dissolution, winding up, liquidation,
reorganization, arrangement, adjustment or composition of it or its debts under
any law relating to bankruptcy, insolvency or reorganization or relief of
debtors or fails to file an answer or other pleading denying the material
allegations of or consents to or acquiesces in any such proceeding filed against
it, (vi) makes any board of directors resolution in direct furtherance of any
matter described in clauses (i) through (v), inclusive, above, or (vii) fails to
contest in good faith any appointment or proceeding described in this Section
8.1(g);

     (h) a custodian, receiver, trustee, liquidator or similar official is
appointed for the Company or any Material Subsidiary or any substantial part of
its property under the Bankruptcy Code or under the bankruptcy or insolvency
laws of another country or a political subdivision of such country, or a
proceeding described in Section 8.1(g)(v) is instituted against the Company or
any Material Subsidiary, and such appointment continues undischarged or such
proceeding continues undismissed and unstayed for a period of sixty (60) days
(or one hundred twenty (120) days in the case of any such event occurring
outside the United States of America);

     (i) the Company or any Subsidiary of the Company fails within thirty (30)
days with respect to a judgment or order that is rendered in the United States
or sixty (60) days with respect to a judgment or order that is rendered in a
foreign jurisdiction (or such earlier date as any execution on such judgment or
order shall take place) to vacate, pay, bond or otherwise discharge any judgment
or order for the payment of money the uninsured portion of which is in excess of
$15,000,000 and which is not stayed on appeal or otherwise being appropriately
contested in good faith in a manner that stays execution;

     (j) the Company or any Subsidiary of the Company fails to pay when due an
amount aggregating in excess of $5,000,000 that it is liable to pay to the PBGC
or to a Plan under Title IV of ERISA; or a notice of intent to terminate a Plan
having Unfunded Vested Liabilities of the Company or any of its Subsidiaries in
excess of $5,000,000 (a "Material Plan") is filed under Title IV of ERISA; or
the PBGC institutes proceedings under Title IV of ERISA to terminate or to cause

                                Attachment A-21
<PAGE>
 
a trustee to be appointed to administer any Material Plan or a proceeding is
instituted by a fiduciary of any Material Plan against any Company or any
Subsidiary to collect any liability under Section 515 or 4219(c)(5) of ERISA,
and in each case such proceeding is not dismissed within thirty (30) days
thereafter; or a condition exists by reason of which the PBGC would be entitled
to obtain a decree adjudicating that any Material Plan must be terminated;

     (k) any Credit Party or any Person authorized to act on behalf of a Credit
Party challenges the validity of any Financing Document or such Credit Party's
obligations thereunder in any material respect, or any Financing Document
ceases, other than in accordance with its terms, to be valid and binding or
ceases, in any material respect, other than in accordance with its terms, to
give to the Noteholders or the Collateral Agent, as the case may be, the Liens,
rights, and powers purported to be granted in their favor thereby;

     (l) the Company or any Subsidiary of the Company shall default in any
payment under any Interest Rate Protection Agreement or futures agreement
permitted pursuant to Section 6.15(g) or (h) of the Existing Credit Agreement
when obligated to make such payment, whether by acceleration or otherwise, and
such payment default shall continue after any applicable grace period and be in
an amount in excess of $5,000,000 when aggregated with all Indebtedness
described in Section 8.1(f) which is then in default as described in Section
8.1(f);

     (m) any event of default under the Credit Agreement shall occur after any
applicable grace period therefor;

     (n) any Person or two or more Persons acting in concert shall acquire
beneficial ownership (within the meaning of Rule 13d-3 of the SEC under the
Securities Exchange Act of 1934, as amended), directly or indirectly, of
securities of the Company (or other securities convertible into such securities)
representing fifty percent (50%) or more of the combined voting power of all
outstanding securities of the Company entitled to vote in the election of
directors, other than securities having such power only by reason of the
happening of a contingency; or

     (o) any event of default under any letter of credit or reimbursement
agreement by and between the Company and the agent under the Credit Agreement
shall occur after any applicable grace period therefor."


(S)A.7. SECTION 8.2(A) OF THE EXISTING NOTE PURCHASE AGREEMENTS IS AMENDED AND
        RESTATED IN ITS ENTIRETY TO READ AS FOLLOWS:

          "(A)  ACCELERATION ON EVENT OF DEFAULT.

               (i) If any Event of Default specified in Section 8.1(g) or
          Section 8.1(h) hereof shall exist with respect to the Company, all of
          the Notes at the time outstanding shall automatically become
          immediately due and payable together with interest accrued thereon
          and, to the extent permitted by law, the Make-Whole Amount at such
          time with respect to the principal amount of such Notes, without
          presentment, demand, protest or notice of any kind, all of which are
          hereby expressly waived, and,

                                Attachment A-22
<PAGE>
 
               (ii) If any Event of Default other than those specified in
          Section 8.1(g) and Section 8.1(h) hereof shall exist with respect to
          the Company (including, without limitation, any Event of Default
          specified in Section 8.1(g) or Section 8.1(h) with respect to any
          Material Subsidiary), the holder or holders of at least thirty-three
          and one-third percent (33%) in principal amount of the Notes then
          outstanding (exclusive of Notes then owned by any one or more of the
          Company, any Subsidiary or any Affiliate) may exercise any right,
          power or remedy permitted to such holder or holders by law, and shall
          have, in particular, without limiting the generality of the foregoing,
          the right to declare the entire principal of, and all interest accrued
          on, all the Notes then outstanding to be, and such Notes shall
          thereupon become, forthwith due and payable, without any presentment,
          demand, protest or other notice of any kind, all of which are hereby
          expressly waived, and the Company shall forthwith pay to the holder or
          holders of all the Notes then outstanding the entire principal of, and
          interest accrued on, the Notes and, to the extent permitted by law,
          the Make-Whole Amount at such time with respect to such principal
          amount of such Notes."


(S)A.8. SECTION 8.2(B) OF THE EXISTING NOTE PURCHASE AGREEMENTS IS AMENDED AND
        RESTATED IN ITS ENTIRETY TO READ AS FOLLOWS:

               "(B)  ACCELERATION ON PAYMENT DEFAULT.  During the existence of
          an Event of Default described in Section 8.1(a) hereof, and
          irrespective of whether the Notes then outstanding shall have been
          declared to be due and payable pursuant to Section 8.2(a)(ii) hereof,
          any holder of Notes who or which shall have not consented to any
          waiver with respect to such Event of Default may, at his or its
          option, by notice in writing to the Company, declare the Notes then
          held by such holder to be, and such Notes shall thereupon become,
          forthwith due and payable together with all interest accrued thereon,
          without any presentment, demand, protest or other notice of any kind,
          all of which are hereby expressly waived, and the Company shall
          forthwith pay to such holder the entire principal of and interest
          accrued on such Notes and, to the extent permitted by law, the Make-
          Whole Amount at such time with respect to such principal amount of
          such Notes."


(S)A.9. SECTION 8.2 OF THE EXISTING NOTE PURCHASE AGREEMENTS IS AMENDED BY
        ADDING A NEW SUBSECTION (F) AT THE END OF SUCH SECTION TO READ AS
        FOLLOWS:

          "(F)  SECURITY DOCUMENTS.  The Noteholders shall, subject to the terms
     of the Intercreditor Agreement, be entitled to all of the rights, benefits
     and remedies provided to them in the Security Documents."


(S)A.10. SECTION 9.1 OF THE EXISTING NOTE PURCHASE AGREEMENTS IS AMENDED BY
         DELETING THE FOLLOWING DEFINITIONS FROM SUCH SECTION:

     ASSET MEASUREMENT PERIOD

                                Attachment A-23
<PAGE>
 
     ASSET SALE

     ASSET VALUE

     BASKET LIENS

     BUSINESS DAY (being replaced by this Amendment No. 1.)

     CAPITAL LEASE

     CLASS

     COMPANY WHOLLY-OWNED TANGIBLE NET WORTH

     COMPANY U.S. TANGIBLE NET WORTH

     CONSOLIDATED EBITDR

     CONSOLIDATED FIXED CHARGE COVERAGE RATIO

     CONSOLIDATED FREE CASH FLOW

     CONSOLIDATED FUNDED DEBT

     CONSOLIDATED INTANGIBLE ASSETS

     CONSOLIDATED INTEREST EXPENSE

     CONSOLIDATED NET INCOME

     CONSOLIDATED OPERATING INCOME

     CONSOLIDATED PRIORITY DEBT

     CONSOLIDATED RENTAL EXPENSE

     CONSOLIDATED TANGIBLE ASSETS (being replaced by this Amendment No. 1.)

     CONSOLIDATED TANGIBLE NET WORTH

     CONSOLIDATED TANGIBLE NET WORTH AMOUNT

     CONSOLIDATED TOTAL CAPITALIZATION

     CREDIT AGREEMENT (being replaced by this Amendment No. 1.)

     ENVIRONMENTAL PROTECTION LAW

                                Attachment A-24
<PAGE>
 
     ERISA (being replaced by this Amendment No. 1.)

     EXCHANGE ACT

     EXCLUDED INVESTMENTS

     FAIR MARKET VALUE

     FISCAL QUARTER

     FOREIGN PENSION PLAN (being replaced by this Amendment No. 1.)

     FUNDED DEBT

     GAAP (being replaced by this Amendment No. 1.)

     GOVERNMENTAL AUTHORITY

     INDEBTEDNESS (being replaced by this Amendment No. 1.)

     INTANGIBLE ASSETS

     INVESTMENT (being replaced by this Amendment No. 1.)

     IRC

     LIEN (being replaced by this Amendment No. 1.)

     MATERIAL ADVERSE EFFECT (being replaced by this Amendment No. 1.)

     MATERIAL SUBSIDIARY (being replaced by this Amendment No. 1.)

     MONTHLY YEAR-TO-DATE INCREASE AMOUNT

     MULTIEMPLOYER PLAN

     PBGC (being replaced by this Amendment No. 1.)

     PENSION PLAN

     PERMITTED BUSINESS (being replaced by this Amendment No. 1.)

     PERSON (being replaced by this Amendment No. 1.)

     PURCHASE MONEY LIENS

     QUARTERLY YEAR-TO-DATE INCREASE AMOUNT

                                Attachment A-25
<PAGE>
 
     RESTRICTED PAYMENT

     RESTRICTED SUBSIDIARY

     SALE/LEASEBACK TRANSACTION

     SECTION 6.9(N) COMPANY

     SUBSIDIARY (being replaced by this Amendment No. 1.)

     TRANSFER (being replaced by this Amendment No. 1.)

     UNRESTRICTED SUBSIDIARY

     WHOLLY-OWNED RESTRICTED SUBSIDIARIES

     WHOLLY-OWNED FOREIGN RESTRICTED SUBSIDIARIES

     WHOLLY-OWNED U.S. RESTRICTED SUBSIDIARIES


(S)A.11. SECTION 9.1 OF THE EXISTING NOTE PURCHASE AGREEMENTS IS AMENDED BY
         ADDING THE FOLLOWING DEFINITIONS IN THEIR APPROPRIATE ALPHABETICAL
         ORDER IN SUCH SECTION:

     "Amendment No. 1 Effective Date" has the meaning specified in Section 4.2
of Amendment No. 1.

     "Amendment No. 1" means Amendment No. 1 to Note Purchase Agreements, dated
as of September 6, 1996, among the Company and the Persons identified in Annex 1
thereto as "Current Noteholders."

     "Business Day" means:

          (a)  as used in Section 6 or Section 8.1, any day other than a
     Saturday or Sunday on which banks are not authorized or required to close
     in Houston, Texas, or New York, New York and

          (b)  as used in any Section of this Agreement other than Section 6 or
     Section 8.1, a day other than a Saturday, a Sunday or, a day on which the
     bank designated by the holder of a Note to receive for such holder's
     account payments on such Note is required by law to be closed.

     "C.A. Effective Date" means July 30, 1996.

     "Capitalized Lease Obligations" means, for any Person, the amount of such
Person's liabilities under all leases of real or personal property (or any
interest therein) which is required to be capitalized on the balance sheet of
such Person as determined in accordance with GAAP.

                                Attachment A-26
<PAGE>
 
     "Cash Equivalents" means (i) securities issued or directly and fully
guaranteed or insured by the United States of America or any agency or
instrumentality thereof having maturities of not more than twelve (12) months
from the date of acquisition, (ii) time deposits and certificates of deposits
maturing within one year from the date of acquisition thereof or repurchase
agreements with financial institutions whose short-term unsecured debt rating is
A or above as obtained from either S&P or Moody's, (iii) commercial paper or
Eurocommercial paper with a rating of at least A-1 by S&P or at least P-1 by
Moody's, with maturities of not more than twelve (12) months from the date of
acquisition, (iv) repurchase obligations entered into with any lender under the
Credit Agreement, or any other Person whose short-term senior unsecured debt
rating from S&P is at least A-1 or from Moody's is at least P-1, which are
secured by a fully perfected security interest in any obligation of the type
described in (i) above and has a market value of the time such repurchase is
entered into of not less than 100% of the repurchase obligation of such lender
or such other Person thereunder, (v) marketable direct obligations issued by any
state of the United States of America or any political subdivision of any such
state or any public instrumentality thereof maturing within twelve (12) months
from the date of acquisition thereof or providing for the resetting of the
interest rate applicable thereto not less often than annually and, at the time
of acquisition, having one of the two highest ratings obtainable from either S&P
or Moody's, (vi) money market funds which have at least $1,000,000,000 in assets
and which invest primarily in securities of the types described in clauses (i)
through (v) above, and (vii) temporary investments of cash not otherwise
permitted above to the extent the same is being held to fund reasonably
anticipated working capital needs, such investments described in this clause
(vii) not to exceed at any time outstanding the equivalent of $10,000,000.

     "Code" means the Internal Revenue Code of 1986, as amended.

     "Collateral Agent" has the meaning specified in or pursuant to the Existing
Intercreditor Agreement.

     "Compulsory Acquisition" has the meaning ascribed to such term in the Offer
to Purchase (as delivered to each Noteholder).

     "Consolidated Adjusted Net Income" means, for any period, (i) the net
income (or loss), after provision for taxes, of the Company and its Subsidiaries
for such period on a consolidated basis determined in accordance with GAAP,
excluding the effects of (v) extraordinary gains or losses, together with any
related provisions for taxes, (w) the net income (or loss) of any Person that is
not a Subsidiary, (x) the net income (or loss) of any Subsidiary to the extent
such Subsidiary is subject to any agreement restricting or limiting the
declaration or payment of dividends or any other distributions to the Company or
any intermediate parent company of such Subsidiary (1) other than agreements as
to formalities required to declare or make a dividend or distribution,
agreements that require retention of reasonable cash reserves for working
capital purposes, or any APB23 declarations, and (2) except to the extent cash
dividends or distributions have actually been paid out of such Subsidiary during
such period, (y) the net income (or loss) of Persons (other than Persons that
are already Subsidiaries during such period) acquired by, merged into or
consolidated with the Company or any of its Subsidiaries earned before the
effective date of such acquisition, merger or consolidation, and (z) non-
recurring writeoffs and costs and expenses in connection with the Exchange
Offer, the Mandatory Bid and the Compulsory Acquisition, if any; plus (ii)
dividends 

                                Attachment A-27
<PAGE>
 
or distributions received by the Company and its Subsidiaries during such period
from SPVs or other Persons that are not Subsidiaries.

     "Consolidated Interest Expense" means, for any period, total interest
expense of the Company and its Subsidiaries on a consolidated basis for such
period, in connection with Indebtedness, all as determined in accordance with
GAAP, but excluding capitalized interest expense and interest expense
attributable to expected federal income tax settlements.

     "Consolidated Interest Income" means, for any period, total interest income
of the Company and its Subsidiaries on a consolidated basis for such period in
connection with Indebtedness, determined in accordance with GAAP.

     "Consolidated Net Worth" means, as of any date of determination, the
Company's consolidated stockholders equity determined in accordance with GAAP,
excluding any capital stock subject to mandatory redemption before the Maturity
Date.  For purposes of this definition, SPVs shall be accounted for pursuant to
the equity method of accounting.

     "Consolidated Tangible Assets" means, as of any date of determination, an
amount equal to the aggregate book value of the assets of the Company, its
Subsidiaries and, to the extent of the equity interest of the Company and its
Subsidiaries therein, SPVs at such time determined on a consolidated basis minus
the aggregate book value of Intangible Assets of the Company, its Subsidiaries
and, to the extent of the equity interest of the Company and its Subsidiaries
therein, SPVs at such time determined on a consolidated basis, in accordance
with GAAP.

     "Controlling Affiliate" means for the Company, (i) any other Person that
directly or indirectly through one or more intermediaries controls, or is under
common control with, the Company (other than Persons controlled by the Company),
and (ii) any other Person owning beneficially or controlling ten percent (10%)
or more of the equity interests in the Company.  As used in this definition,
"control" means the power, directly or indirectly, to direct or cause the
direction of management or policies of a Person (through ownership of voting
securities or other equity interests, by contract or otherwise).

     "Credit Agreement" means the Secured Credit Agreement, dated as of July 30,
1996, among: (i) the Company; (ii) the lenders from time to time a party
thereto; (iii) ABN AMRO Bank N.V., as agent for such lenders; (iv) SunTrust
Bank, Atlanta and Credit Lyonnais New York Branch, as documentation agents for
such lenders; and (v) Bank of Montreal, The Fuji Bank, Limited, Royal Bank of
Canada, and Wells Fargo Bank, as co-agents for such lenders, as the same may be
amended, supplemented or otherwise modified from time to time.

     "Credit Documents" has the meaning specified in the Existing Credit
Agreement.

     "Credit Party" means the Company or any Guarantor.

     "Dollar" and "U.S. Dollar" and the sign "$" mean lawful money of the United
States of America.

                                Attachment A-28
<PAGE>
 
     "EBIT" means, for any period, Consolidated Adjusted Net Income before (i)
Consolidated Interest Expense and interest expense attributable to expected
federal income tax settlements, and (ii) provisions for taxes based on income or
revenues, all as determined in accordance with GAAP for such period.

     "EBITDA" means, for any period, (i) EBIT plus (ii) the amount of all
depreciation and amortization expense deducted in determining Consolidated
Adjusted Net Income, all as determined in accordance with GAAP for such period.

     "Environmental Claims" means any and all administrative, regulatory or
judicial actions, suits, demands, demand letters, claims, liens, notices of non-
compliance or violation, investigations or proceedings relating to any
Environmental Law ("Claims") or any permit issued under any Environmental Law,
including, without limitation, (i) 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 (ii)
any and all Claims by any third party seeking damages, contribution,
indemnification, cost recovery, compensation or injunctive relief resulting from
Hazardous Materials or arising from alleged injury or threat of injury to the
environment.

     "Environmental Law" means any federal, state or local statute, law, rule,
regulation, ordinance, code, policy or rule of common law now or hereafter in
effect, including any judicial or administrative order, consent, decree or
judgment, relating to the environment.

     "ERISA" means the Employee Retirement Income Security Act of 1974, as
amended.

     "Event of Default" means any of the events or circumstances specified in
Section 8.1.

     "Exchange Offer" means the "Exchange Offer" of the Company for the shares
of Transocean made pursuant to the Offer to Purchase (as delivered to each
Noteholder).

     "Exchange Offer Consummation Date" means the date the Exchange Offer is
consummated.

     "Existing Credit Agreement" means the Credit Agreement as in effect on the
Amendment No. 1 Effective Date.

     "Existing Credit Documents" means the Credit Documents as in effect on the
Amendment No. 1 Effective Date.

     "Existing Intercreditor Agreement" means the Intercreditor Agreement as in
effect on the Amendment No. 1 Effective Date, or as subsequently amended or
otherwise modified with the written consent of the Company.

     "Fees" is defined in Section 6.30.

     "Financing Documents" means the Note Purchase Agreements, the Notes,
Amendment No. 1 and the Security Documents, as any of the same may be amended,
supplemented or otherwise 

                                Attachment A-29
<PAGE>
 
modified from time to time (including, without limitation, in the case of the
Note Purchase Agreements, by Amendment No. 1).

     "Foreign Plan" means any pension, profit sharing, deferred compensation, or
other employee benefit plan, program or arrangement maintained by any foreign
Subsidiary of the Company which, under applicable local law, is required to be
funded through a trust or other funding vehicle, but shall not include any
benefit provided by a foreign government or its agencies.

     "GAAP" means generally accepted accounting principles from time to time in
effect as set forth in the opinions and pronouncements of the Accounting
Principles Board of the American Institute of Certified Public Accountants and
the statements and pronouncements of the Financial Accounting Standards Board or
in such other statements, opinions and pronouncements by such other entity as
may be approved by a significant segment of the U.S. accounting profession.

     "Guarantor" means any of Sonat Offshore Norway Inc., Sonat Offshore
Ventures Inc., Sonat Turnkey Drilling Inc. and Sonat Offshore (U.K.) Inc. or any
other domestic Subsidiary of the Company required to become a Guarantor pursuant
to Section 6.11 of the Credit Agreement, or that otherwise becomes a guarantor
under a Subsidiary Guaranty, in each case unless and until the relevant
Subsidiary Guaranty is released pursuant to Section 6.11 of the Credit Agreement
or in accordance with the Existing Intercreditor Agreement or Section 3.5 or
Section 3.4 of the relevant Subsidiary Guaranty.

     "Guaranty" by any Person means all contractual obligations (other than
endorsements in the ordinary course of business of negotiable instruments for
deposit or collection or similar transactions in the ordinary course of
business) of such Person guaranteeing any Indebtedness, dividend or other
obligation (including, without limitation, obligations in connection with sales
of any property) of any other Person (the "primary obligor") in any manner,
whether directly or indirectly, including, without limitation, all obligations
incurred through an agreement, contingent or otherwise, by such Person: (i) to
purchase such Indebtedness or obligation, or to purchase any property or assets
constituting security therefor, primarily for the purpose of assuring the owner
of such Indebtedness or obligations of the ability of the primary obligor to
make payment of such Indebtedness or obligation; or (ii) to advance or supply
funds (x) for the purchase or payment of such Indebtedness or obligation, or (y)
to maintain working capital or other balance sheet condition, or otherwise to
advance or make available funds for the purchase or payment of such Indebtedness
or obligation, in each case primarily for the purpose of assuring the owner of
such Indebtedness or obligation of the ability of the primary obligor to make
payment of such Indebtedness or obligation; or (iii) to lease property, or to
purchase securities or other property or services, of the primary obligor,
primarily for the purpose of assuring the owner of such Indebtedness or
obligation of the ability of the primary obligor to make payment of such
Indebtedness or obligation; or (iv) otherwise to assure the owner of such
Indebtedness or obligation of the primary obligor against loss in respect
thereof.  For the purpose of all computations made under this Agreement, the
amount of a Guaranty in respect of any obligation shall be deemed to be equal to
the amount that would apply if such obligation was the direct obligation of such
Person rather than the primary obligor or, if less, the maximum aggregate
potential liability of such Person under the terms of the Guaranty.

                                Attachment A-30
<PAGE>
 
     "Hazardous Material" shall have the meaning assigned to that term in the
Comprehensive Environmental Response Compensation and Liability Act of 1980, as
amended by the Superfund Amendments and Reauthorization Acts of 1986, and shall
also include petroleum, including crude oil or any fraction thereof, or any
other substance defined as "hazardous" or "toxic" or words with similar meaning
and effect under any Environmental Law applicable to the Company or any of its
Subsidiaries.

     "Indebtedness" means, for any Person, the following obligations of such
Person, without duplication:  (i) obligations of such Person for borrowed money;
(ii) obligations of such Person representing the deferred purchase price of
property or services other than accounts payable arising in the ordinary course
of business and other than amounts which are being contested in good faith and
for which reserves in conformity with GAAP have been provided; (iii) obligations
of such Person evidenced by bonds, notes, bankers acceptances, debentures or
other similar instruments of such Person or arising, whether absolute or
contingent, out of letters of credit issued for such Person's account or
pursuant to such Person's application; (iv) obligations of other Persons,
whether or not assumed, secured by Liens (other than Permitted Liens) upon
property or payable out of the proceeds or production from property now or
hereafter owned or acquired by such Person, but only to the extent of such
property's fair market value; (v) Capitalized Lease Obligations of such Person;
(vi) obligations under (x) Interest Rate Protection Agreements, (y) commodity
hedge, swap, exchange, forward, future, collar or cap arrangements, fixed price
commodity agreements and all other agreements or arrangements, in each case
designed primarily to protect against fluctuations in commodity prices, and (z)
futures agreements, arrangements or options designed primarily to protect
against fluctuations in currency exchange rates; and (vii) obligations of such
Person pursuant to a Guaranty of any of the foregoing of another Person;
provided, however, Indebtedness shall exclude Non-recourse Debt.  For purposes
of this Agreement, the Indebtedness of any Person shall include the Indebtedness
of any partnership or joint venture to the extent such Indebtedness is recourse
to such Person.

     "Indebtedness Document" is defined in Section 6.31(a).

     "Initial Borrowing Date" means the date of the initial borrowing by the
Company under the Credit Agreement, which date shall be no later than September
30, 1996.

     "Institutional Funded Indebtedness" is defined in Section 6.31(b).

     "Intangible Assets" means patents, copyrights, trademarks, trade names,
service marks, brand names, franchises, goodwill, experimental expenses and
other similar intangibles, and all other property which would be considered to
be intangible under GAAP.

     "Intercreditor Agreement" is defined in Attachment C to Amendment No. 1.

     "Interest Coverage Ratio" means, as of the end of any fiscal quarter, the
ratio of (i) EBITDA for the four fiscal quarter period then ended, minus all
dividends paid to shareholders of the Company during such four fiscal quarter
period and all cash income taxes paid during such four fiscal quarter period, to
(ii) Consolidated Interest Expense for the four fiscal quarter period then
ended; provided that for the first three (3) full fiscal quarters ended after
the Exchange Offer 

                                Attachment A-31
<PAGE>
 
Consummation Date, the Interest Coverage Ratio shall be determined for the
number of full fiscal quarters ended after the Exchange Offer Consummation Date
only.

     "Interest Rate Protection Agreement" shall mean any interest rate swap,
interest rate cap, interest rate collar, or other interest rate hedging
agreement or arrangement designed to protect against fluctuations in interest
rates.

     "Investment Grade Condition" shall be deemed to be satisfied at any time if

          (a) the senior unsecured long-term Indebtedness of the Company shall
     at such time be rated "BBB-" or higher by S&P and "Baa3" or higher by
     Moody's, or

          (b) the senior unsecured long-term Indebtedness of the Company shall
     at such time be rated "BBB-" or higher by S&P and "Baa3" or higher by
     Moody's, assuming for purposes of both of such ratings (which assumption
     shall be made explicit by both S&P and Moody's in their respective rating
     letters) that the Liens and Guaranties provided for by the Security
     Documents shall have been released and terminated before or at such time,
     whether or not such Liens and Guaranties actually shall have been released
     and terminated.

     "Lien" means any interest in any property or asset in favor of a Person
other than the owner of such property or asset and securing an obligation owed
to, or a claim by, such Person, whether such interest is based on the common
law, statute or contract, including, but not limited to, the security interest
lien arising from a mortgage, encumbrance, pledge, conditional sale, security
agreement or trust receipt, or a lease, consignment or bailment for security
purposes.

     "Mandatory Bid" has the meaning ascribed to such term in the Offer to
Purchase (as delivered to each Noteholder).

     "Mandatory Bid Bank Guarantee" means any bank guarantee issued by a bank at
the request of the Company in connection with the Mandatory Bid as required
under Norwegian law or by the Oslo Stock Exchange, which guarantee shall be in a
maximum amount no greater than the aggregate cash purchase price offered for the
shares of Transocean stock in the Mandatory Bid, together with interest thereon
as is required under Norwegian law or by the Oslo Stock Exchange.

     "Material Adverse Effect" means an effect that results in a material
adverse (i) change, since March 31, 1996 (or after the Exchange Offer
Consummation Date, since the Exchange Offer Consummation Date), in (x) the
business, properties, assets, financial condition or (prior to the Initial
Borrowing Date) prospects of (a) before the Exchange Offer Consummation Date,
the Company and its Subsidiaries taken as a whole, or Transocean and its
Subsidiaries taken as a whole, or (b) after the Exchange Offer Consummation
Date, the Company and its Subsidiaries taken as a whole, or (y) the ability of
the Company or the Company and the other Credit Parties taken as a whole to
perform their payment obligations under the Note Purchase Agreements, the Notes
or the other Financing Documents to which they are parties, or (ii) change in
the rights and remedies of the Noteholders in any material adverse respect under
the any of the Financing Documents (other than in accordance with the express
terms thereof).

                                Attachment A-32
<PAGE>
 
     "Material Subsidiary" means Sonat Offshore Norway Inc., Sonat Offshore
Ventures Inc., Sonat Turnkey Drilling Inc., Sonat Offshore U.K. Inc., Sonat
Offshore Far East and, after the Exchange Offer Consummation Date, NSub and
Transocean (in each case for so long as such entity is a Subsidiary), and each
other Subsidiary of the Company that has total assets (excluding assets that
would be eliminated in consolidation with the Company and its Subsidiaries)
which equates to at least five percent (5%) of the Company's Total Assets or
that had net income (determined in accordance with GAAP but excluding revenues
and expenses that would be eliminated in consolidation with the Company and its
Subsidiaries) during the most recently completed fiscal year of the Company in
excess of the greater of (i) $1,000,000 and (ii) fifteen percent (15%) of
Consolidated Adjusted Net Income during such fiscal year of the Company.

     "Maturity Date" means February 15, 2004.

     "Moody's" means Moody's Investors Service, Inc., or any successor thereto.

     "Non-recourse Debt" means with respect to any Person (i) obligations of
such Person against which the obligee has no recourse to such Person except as
to certain named or described present or future assets or interests, and (ii)
the obligations of SPVs to the extent the obligee thereof has no recourse to the
Company or any of its Subsidiaries.

     "Noteholders" means the holders, from time to time, of the Notes.

     "Note Pledge Agreement" is defined in Attachment C to Amendment No. 1.

     "Note Purchase Agreements" means this Agreement and the other note purchase
agreement under which the Notes were issued, as either of the same may be
amended, supplemented or otherwise modified from time to time (including,
without limitation, by Amendment No. 1).

     "NPA Corresponding Restrictive Covenants" is defined in Section 6.31(a).

     "NSub" means a company to be organized by the Company under the laws of the
Kingdom of Norway to hold the stock of Transocean immediately after the Exchange
Offer Consummation Date.

     "Offer to Purchase" means the definitive Prospectus/Offer to Purchase/Proxy
Statement of the Company relating to the Exchange Offer, as amended or extended
by the Company.

     "Other Indebtedness More Onerous Restrictive Covenants" is defined in
Section 6.31(a).

     "PBGC" means the Pension Benefit Guaranty Corporation or any successor
thereto.

     "Performance Guaranties" means all Guaranties of the Company or any of its
Subsidiaries delivered in connection with the construction financing of drill
ships, offshore mobile drilling units or offshore drilling rigs for which firm
drilling contracts have been obtained by the Company, any of its Subsidiaries or
a SPV.

                                Attachment A-33
<PAGE>
 
     "Performance Letters of Credit" means all letters of credit for the account
of the Company, any Subsidiary or a SPV issued as support for Non-recourse Debt
or a Performance Guaranty.

     "Permitted Business" has the meaning ascribed to such term in Section 6.9.

     "Permitted Liens" means the Liens described in Section 6.14.

     "Person" means an individual, partnership, corporation, limited liability
company, association, trust, unincorporated organization or any other entity or
organization, including a government or any agency or political subdivision
thereof.

     "Plan" means an employee pension benefit plan covered by Title IV of ERISA
or subject to the minimum funding standards under Section 412 of the Code that
is either (i) maintained by the Company or any of its Subsidiaries, or (ii)
maintained pursuant to a collective bargaining agreement or any other
arrangement under which more than one employer makes contributions and to which
the Company or any of its Subsidiaries is then making or accruing an obligation
to make contributions or has within the preceding five (5) plan years made or
had an obligation to make contributions.

     "Put Prepayment Date" is defined in Section 4.6(a).

     "Restrictive Covenants" is defined in Section 6.31(c).

     "SEC" means the Securities and Exchange Commission.

     "S&P" means Standard & Poor's Ratings Group or any successor thereto.

     "Security Documents" means the Stock Pledge Agreement, the Note Pledge
Agreement, the Subsidiary Guaranties, Section 7.4 of the Existing Credit
Agreement and any other security agreements, mortgages and like agreements or
instruments delivered by the Company or any Guarantor granting a Lien on any of
such Person's property to the Collateral Agent for the benefit (without
limitation) of the Noteholders and the lenders under the Credit Agreement to
secure (without limitation) the Company's payment obligations under the
Financing Documents and the Credit Documents (provided that nothing in this
definition shall be deemed to constitute the consent of any Noteholder to the
granting of any Lien not expressly permitted by Section 6.14), as any of the
same may be amended, supplemented or otherwise modified from time to time.

     "SODI Credit Facility" means that certain Amended and Restated Credit
Agreement dated as of December 28, 1995, by and among the Company, SunTrust
Bank, Atlanta, as agent, ABN AMRO, as co-agent, and certain lenders parties
thereto.

     "SPV" means any Person that is not a Guarantor that is designated by the
Company as a SPV (no such Persons having yet been so designated by the Company
as of the Amendment No. 1 Effective Date), provided that the Company shall not
designate as a SPV any Subsidiary that owns, directly or indirectly, any
Material Subsidiary or Guarantor.  The Company may elect to treat any Subsidiary
as a SPV (provided such Subsidiary would otherwise qualify as such), and may
rescind any such prior election, by giving written notice thereof to each
Noteholder specifying the 

                                Attachment A-34
<PAGE>
 
name of such Subsidiary or SPV, as the case may be, and the effective date of
such election, which shall be a date within sixty (60) days after the date such
notice is given. The election to treat a particular Person as a SPV may only be
made once.

     "Stock Pledge Agreement" is defined in Attachment C to Amendment No. 1.

     "Subsidiary" means, for any Person, any other Person (other than, except in
the context of Section 6.7(a), a SPV) of which more than fifty percent (50%) of
the outstanding stock or comparable equity interests having ordinary voting
power for the election of the board of directors of such corporation, any
managers of such limited liability company or similar governing body
(irrespective of whether or not at the time stock or other equity interests of
any other class or classes of such corporation or other entity shall have or
might have voting power by reason of the happening of any contingency), is at
the time directly or indirectly owned by such former Person or by one or more of
its Subsidiaries.

     "Subsidiary Guaranty" means any Guaranty of any Subsidiary delivered
pursuant to Attachment C to Amendment No. 1 or Section 6.11 of the Credit
Agreement.

     "Taxes" means all governmental taxes, rates, assessments, fees, charges and
levies.

     "Total Assets" means, as of any date of determination, the aggregate book
value of the assets of the Company and its Subsidiaries determined on a
consolidated basis in accordance with GAAP as of such date.

     "Total Capital" means, as of any date of determination, the sum of Total
Funded Debt plus Consolidated Net Worth as of such date.

     "Total Funded Debt" means, as of any date of determination, the sum
(without duplication) of (i) Indebtedness for borrowed money, all obligations
evidenced by bonds, debentures, notes or similar instruments, and obligations to
pay the deferred purchase price of property which in accordance with GAAP would
be shown on a consolidated balance sheet as a liability, (ii) all obligations,
contingent or otherwise, relative to the face amount of letters of credit and
bankers acceptances issued and outstanding and (iii) all obligations as lessee
under leases which are required to be recorded as Capitalized Lease Obligations
in accordance with GAAP, all calculated on a consolidated basis for the Company
and its Subsidiaries; provided,  however, Total Funded Debt shall exclude (x)
Non-recourse Debt, (y) Performance Letters of Credit and Performance Guaranties
until any such Performance Letter of Credit is drawn upon or any such
Performance Guarantee is called upon, in which case the aggregate amount drawn
thereunder or called upon, and unpaid from time to time, shall be included from
and after the date and time of such event and (z) letters of credit issued and
outstanding in the ordinary course of business to comply with governmental
requirements relating to the import and export of vessels until any such letter
of credit is drawn upon, in which case the aggregate amount drawn thereunder and
unpaid from time to time shall be included from and after the date and time of
such event.

     "Total Funded Debt to Total Capital Ratio" means, as of any date, the
ratio, expressed as a percentage, of Total Funded Debt to Total Capital.  For
purposes of this ratio, (i) until the delivery of the consolidated balance sheet
of the Company as of September 30, 1996, Consolidated Net 

                                Attachment A-35
<PAGE>
 
Worth shall equal $1,580,000,000, and (ii) from and after the delivery of such
consolidated balance sheet, Consolidated Net Worth as of any date shall be
determined as of the date of the most recent consolidated balance sheet of the
Company delivered pursuant to Section 6.7(a)(i) or (ii).

     "Transfer" means a sale, transfer, conveyance, assignment or other
disposition (or a series of related dispositions), including, without
limitation, any transfer pursuant to an option to purchase, any sale or
assignment (with or without recourse) of any accounts receivable and any sale
and leaseback of assets, of an asset having a net book value as established in
accordance with GAAP in excess of $250,000, but excluding any involuntary
transfer by operation of law and any transfers of an asset pursuant to any
casualty or theft with respect to such asset.

     "Transocean" means Transocean ASA, a company organized under the laws of
the Kingdom of Norway.

     "Transocean Credit Facility" means that certain Facility Agreement dated as
of December 20, 1995, by and among Transocean, Den Norske Bank AS as agent and
security agent, Chase Investment Bank Limited, Den Norske Bank AS and
Meespierson N.V., as arrangers, and others.

     "Unfunded Vested Liabilities" means, for any Plan at any time, the amount
(if any) by which the present value of all vested nonforfeitable accrued
benefits under such Plan exceeds the fair market value of all Plan assets
allocable to such benefits, determined as of the then most recent valuation date
for such Plan, but only to the extent that such excess represents a potential
liability of the Company or any of its Subsidiaries to the PBGC or such Plan.


(S)A.12. SECTION 9.2 OF THE EXISTING NOTE PURCHASE AGREEMENTS IS AMENDED AND
         RESTATED IN ITS ENTIRETY TO READ AS FOLLOWS:

     "9.2  Change in Accounting Principles, Fiscal Year or Tax Laws.  If (i) any
change in accounting principles from those used in the preparation of the
financial statements of the Company referred to in Section B.9 of Attachment B
to Amendment No. 1 is hereafter occasioned by the promulgation of rules,
regulations, pronouncements and opinions by or required by the Financial
Accounting Standards Board or the American Institute of Certified Public
Accountants (or successors thereto or agencies with similar functions) other
than changes mandated by SFAS 106 and such change materially affects the
calculation of any component of any financial covenant, standard or term found
in this Agreement, or (ii) there is a material change in federal or foreign tax
laws which materially affects the ability of the Company or of any of its
Subsidiaries to comply with the financial covenants, standards or terms found in
this Agreement, the Company and the Noteholders agree to enter into negotiations
in order to amend (pursuant to Section 10.5) such provisions so as to equitably
reflect such changes with the desired result that the criteria for evaluating
any of the Company's and its Subsidiaries' financial condition shall be the same
after such changes as if such changes had not been made.  Unless and until such
provisions have been so amended, the provisions of this Agreement shall govern."

                                Attachment A-36
<PAGE>
 
(S)A.13. SECTION 9.3 OF THE EXISTING NOTE PURCHASE AGREEMENTS IS AMENDED AND
         RESTATED IN ITS ENTIRETY TO READ AS FOLLOWS:

     "9.3  DIRECTLY OR INDIRECTLY.

     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."


(S)A.14. SECTION 10.5(D) OF THE EXISTING NOTE PURCHASE AGREEMENTS IS AMENDED BY
         REPLACING THE CROSS-REFERENCE TO SECTION 7.4 WITH A CROSS-REFERENCE TO
         SECTION 6.8.


(S)A.15. SECTION 10 OF THE EXISTING NOTE PURCHASE AGREEMENTS IS AMENDED BY
         ADDING THE FOLLOWING NEW SECTIONS 10.10 AND 10.11 AT THE END OF SUCH
         SECTION TO READ AS FOLLOWS:

     "10.10  Officer's Certificates.  It is not intended that any certificate of
any officer of any Credit Party delivered to any Noteholder pursuant to this
Agreement shall give rise to any personal liability on the part of such officer.

     10.11  Effect of Inclusion of Exceptions.  It is not intended that the
specification of any exception to any covenant herein shall imply that the
excepted matter would, but for such exception, be prohibited or required."

                                Attachment A-37
<PAGE>
 
                                                                    ATTACHMENT B

                         WARRANTIES AND REPRESENTATIONS


     The Company makes the following warranties and representations pursuant to
Section 3 (it being understood and agreed that the following representations and
warranties, to the extent made (or deemed made) prior to or on the Amendment No.
1 Effective Date and insofar as they relate to Transocean and its Subsidiaries,
are to the knowledge of the officers of the Company and are based solely on the
Company's review of publicly available information and certain confidential
information made available to the Company by Transocean without making any
representation or warranty as to the accuracy of any such information):

     B.1   Corporate Organization. (a) The Company and each of its Material
Subsidiaries: (i) is a duly organized and existing corporation (or other Person)
in good standing under the laws of the jurisdiction of its organization; (ii)
has all necessary corporate power (or comparable power, in the case of a
Material Subsidiary that is not a corporation) to own the property and assets it
uses in its business and otherwise to carry on its present business; and (iii)
is duly licensed or qualified and in good standing in each jurisdiction in which
the nature of the business transacted by it or the nature of the property owned
or leased by it makes such licensing or qualification necessary except where the
failure to be so licensed or qualified or to be in good standing, as the case
may be, would not have a Material Adverse Effect.

     (b) As of the C.A. Effective Date, the Company and Transocean each had no
Subsidiaries other than those Subsidiaries listed on Schedule 5.1 to the
Existing Credit Agreement.  Such Schedule 5.1 correctly sets forth, as of the
C.A. Effective Date, the percentage ownership (direct and indirect) of the
Company and of Transocean in each class of capital stock of each of its
Subsidiaries.

     B.2   Corporate Power and Authority; Validity.  Each Credit Party has the
corporate power and authority to execute, deliver and carry out the terms and
provisions of the Financing Documents to which it is a party and has taken all
necessary corporate action (or comparable action, in the case of a Credit Party
that is not a corporation) to authorize the execution, delivery and performance
of such Financing Documents.  Each Credit Party has duly executed and delivered
each Financing Document to which it is a party and each such Financing Document
constitutes the legal, valid and binding obligation of such Credit Party
enforceable against it in accordance with its terms, subject as to enforcement
only to bankruptcy, insolvency, reorganization, moratorium or other similar laws
affecting the enforcement of creditors' rights generally and equitable
principles.

     B.3   No Violation.  Neither the execution, delivery or performance by any
Credit Party of the Financing Documents to which it is a party nor compliance by
it with the terms and provisions thereof, nor the consummation by it of the
transactions contemplated herein or therein, will (i) contravene in any material
respect any applicable provision of any law, statute, rule or regulation, or any
applicable order, writ, injunction or decree of any court or governmental
instrumentality, (ii) conflict with or result in any breach of any term,
covenant, condition or other provision of, or constitute a default under, or
result in the creation or imposition of (or the obligation to create or 

                                Attachment B-1
<PAGE>
 
impose) any Lien other than any Permitted Lien upon any of the property or
assets of the Company or any of its Subsidiaries under, the terms of any
material contractual obligation to which the Company or any of its Subsidiaries
is a party or by which they or any of their properties or assets are bound or to
which they may be subject, or (iii) violate or conflict with any provision of
the certificate or articles of incorporation or by-laws or other applicable
corporate governance documents of the Company or any of its Subsidiaries.

     B.4   Litigation.  There are no actions, suits, proceedings or
counterclaims (including, without limitation, derivative or injunctive actions)
pending or, to the knowledge of the Company, threatened against the Company or
any of its Subsidiaries that are reasonably likely to have a Material Adverse
Effect.

     B.5   [Intentionally Omitted.]

     B.6   Investment Company Act.  Neither the Company nor any of its
Subsidiaries is an "investment company" or a company "controlled" by an
"investment company," within the meaning of the Investment Company Act of 1940,
as amended.

     B.7   Public Utility Holding Company Act.  Neither the Company nor any of
its Subsidiaries 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.

     B.8   True and Complete Disclosure.  All factual information (taken as a
whole) furnished by the Company or any of its Subsidiaries in writing to any
Noteholder in connection with Amendment No. 1 or any transaction contemplated
therein is (disregarding any updated, corrected, supplemented, superseded or
otherwise modified information except as so updated, corrected, supplemented,
superseded or otherwise modified on or before the Amendment No. 1 Effective
Date), and all other such factual information hereafter furnished by any such
Persons in writing to any Noteholder in connection herewith, or with any of the
other Financing Documents, will be, on the date of such information, true and
accurate in all material respects 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.

     B.9   Financial Statements.  The financial statements heretofore delivered
to the Noteholders (i) for the Company's and Transocean's fiscal years ending
December 31, 1995, and for the Company's and Transocean's fiscal quarters ending
March 31, 1996, have been prepared in accordance with GAAP and generally
accepted accounting principles in effect in the Kingdom of Norway, respectively,
applied on a basis consistent, except as otherwise noted therein, with such
entity's financial statements for the previous fiscal year.  Each of such annual
and quarterly financial statements fairly presents on a consolidated basis the
financial position of the Company and Transocean, as applicable, as of the dates
thereof, and the results of operations for the periods covered thereby, subject
in the case of interim financial statements, to normal year-end audit
adjustments and omission of certain footnotes (in the case of the Company, as
permitted by the SEC).  As of the C.A. Effective Date, the Company and its
Subsidiaries, considered as a whole, had no material contingent liabilities or
material Indebtedness required under GAAP to be disclosed in a consolidated
balance sheet of the Company that were not disclosed in the financial statements

                                Attachment B-2
<PAGE>
 
referred to in this Section or in the notes thereto or disclosed in writing to
each Noteholder. The pro forma financial statements heretofore delivered to the
Noteholders for the Company as of March 31, 1996, have been prepared on a basis
consistent, except as otherwise noted therein, with the Company's financial
statements for the fiscal quarter ending March 31, 1996.

     B.10  No Material Adverse Change.  There has occurred no event or effect
that has had or is reasonably likely to have a Material Adverse Effect.

     B.11  Labor Controversies.  There are no labor controversies pending or, to
the best knowledge of the Company, threatened against the Company or any of its
Subsidiaries that are reasonably likely to have a Material Adverse Effect.

     B.12  Taxes.  The Company and its Subsidiaries have filed all United States
federal income tax returns, and all other material tax returns required to be
filed, whether in the United States or in any foreign jurisdiction, and have
paid all Taxes shown to be due and payable on such returns or on any assessments
made against Company and its Subsidiaries or any of their properties (other than
any such assessments that are not more than ninety (90) days past due or which
can thereafter be paid without penalty or which are being contested in good
faith by appropriate proceedings and for which reserves have been provided in
conformity with GAAP).

     B.13  ERISA.  With respect to each Plan, the Company and its Subsidiaries
have fulfilled their obligations under the minimum funding standards of, and are
in compliance in all material respects with, ERISA and with the Code to the
extent applicable to it, and have not incurred any liability under Title IV of
ERISA to the PBGC or a Plan other than a liability to the PBGC for premiums
under Section 4007 of ERISA except as described in Schedule 5.13 to the Existing
Credit Agreement, and in each case with such exceptions as are not reasonably
likely to have a Material Adverse Effect.  As of the C.A. Effective Date,
neither the Company nor any of its Subsidiaries had any contingent liability
with respect to any post-retirement benefits under a welfare plan subject to
ERISA, other than liability for continuation coverage described in Part 6 of
Title I of ERISA and as disclosed in the financial statements of the Company for
the fiscal quarter ending March 31, 1996, described in Section B.9.

     B.14  Security Interests.  On and after the Amendment No. 1 Effective Date,
each of the Note Pledge Agreement and the Stock Pledge Agreement will create,
upon the filing of properly completed UCC financing statements in the
appropriate jurisdictions or possession of the collateral referred to therein by
the Collateral Agent if necessary to perfect a security interest in such
collateral, in favor of the Collateral Agent as security for the payment
obligations of the Company under the Financing Documents and the other
obligations referred to in the Security Documents contemplated to be so secured,
a valid and enforceable perfected first priority (subject only to Permitted
Liens) security interest in and Lien on all of the collateral described therein,
subject to no other Liens except Permitted Liens.

     B.15  Consents.  At the time of consummation thereof, all consents and
approvals of, and filings and registrations with, and all other actions of, all
governmental agencies, authorities or instrumentalities required to have been
obtained or made by the Company in order to execute and deliver this Agreement
and to consummate the Amendment have been or will have been obtained or made and
are or will be in full force and effect.

                                Attachment B-3
<PAGE>
 
     B.16  Capitalization.  All outstanding shares of the Material Subsidiaries
of the Company have been duly and validly issued, are fully paid and are
nonassessable, in each case with such exceptions as are not reasonably likely to
have either a Material Adverse Effect or an adverse effect on the control of the
Company of any such Material Subsidiary.  Except as described on Schedule 5.16
to the Existing Credit Agreement, none of the Material Subsidiaries of the
Company, as of the Exchange Offer Consummation Date, had outstanding any
securities convertible into or exchangeable for its capital stock or outstanding
any rights to subscribe for or to purchase, or any options for the purchase of,
or any agreement providing for the issuance (contingent or otherwise) of its
capital stock.

     B.17  Intellectual Property.  The Company and its Subsidiaries own or hold
valid licenses to use all the material patents, trademarks, permits, service
marks, and trade names that are necessary to the operation of the business of
the Company and its Subsidiaries as presently conducted with such exceptions
which are not reasonably likely to have a Material Adverse Effect.

     B.18  Ownership of Property.  The Company and each domestic Material
Subsidiary has good title to or a valid leasehold interest in all of its real
property and good title to, or a valid leasehold interest in, all of its other
property, and each foreign Material Subsidiary owns or has a valid leasehold
interest in all of its real property and owns or has a valid leasehold interest
in, all of its other properties, in each case with such exceptions as are not,
individually or in the aggregate, reasonably likely to have a Material Adverse
Effect, subject to no Liens except Permitted Liens.

     B.19  Compliance with Statutes, Etc.  The Company and its Subsidiaries are
in compliance with all applicable statutes, regulations and orders of, and all
applicable restrictions imposed by, all governmental bodies, domestic and
foreign, in respect of the conduct of their businesses and the ownership of
their properties, except for such instances of non-compliance as are not
reasonably likely to, individually or in the aggregate, have a Material Adverse
Effect.

     B.20  Environmental Matters.  (a)  Except as described in Schedule 5.20 to
the Existing Credit Agreement, the Company and its Subsidiaries are in
compliance with all applicable Environmental Laws and the requirements of any
permits issued under such Environmental Laws, except for such instances of non-
compliance as are not reasonably likely to have a Material Adverse Effect.  To
the best knowledge of the Company, there are no pending, past or threatened
Environmental Claims against the Company or any of its Subsidiaries on any
property owned or operated by the Company or any of its Subsidiaries except as
described in such Schedule 5.20 or except as are not reasonably likely to have a
Material Adverse Effect.  To the best knowledge of the Company, there are no
conditions or occurrences on any property owned or operated by the Company or
any of its Subsidiaries or on any property adjoining or in the vicinity of any
such property that are reasonably likely to form the basis of an Environmental
Claim against the Company or any of its Subsidiaries or any such property that
individually or in the aggregate are reasonably likely to have a Material
Adverse Effect.

     (b) To the best of the Company's knowledge, (i) Hazardous Materials have
not at any time been generated, used, treated or stored on, or transported to or
from, any property owned or operated by the Company or any of its Subsidiaries
in a manner that has violated or could reasonably be expected to violate any
Environmental Law, and (ii) Hazardous Materials have not

                                Attachment B-4
<PAGE>
 
at any time been released on or from any property owned or operated by the
Company or any of its Subsidiaries, in the case of both (i) and (ii), with such
exceptions as are not reasonably likely to have a Material Adverse Effect.

     B.21  Existing Indebtedness.  Schedule 5.21 to the Existing Credit
Agreement contains a complete list of all Indebtedness outstanding as of the
C.A. Effective Date (other than the Indebtedness under the Credit Agreement and
Indebtedness permitted by Section 6.15(c) through (r) of the Existing Credit
Agreement) and permitted by Section 6.15(b) of the Existing Credit Agreement, in
each case showing the aggregate principal amount thereof, the name of the
respective borrower and any other entity which directly or indirectly guaranteed
such Indebtedness, and the scheduled payments of such Indebtedness.

     B.22  Dividend Restrictions.  Except as permitted under Section 6.12 of the
Note Purchase Agreements (assuming for such purpose that the Amendment becomes
effective) or described on Schedule 5.22 to the Existing Credit Agreement, as of
the C.A. Effective Date, none of the Subsidiaries of the Company is party to or
subject to any agreement or understanding restricting or limiting the payment of
any dividends or other distributions on its capital stock by any such
Subsidiary.

     B.23  Credit Agreement.  A true and correct copy of the Credit Agreement,
as in full force and effect as of the C.A. Effective Date and the Amendment No.
1 Effective Date, is attached as Exhibit E.  All conditions precedent referred
to in Section 4.1 of the Credit Agreement related to the initial advance of the
loans by the lenders thereunder have been satisfied (or waived, provided that
the Company shall have notified you in writing of any such conditions that have
been waived) on or prior to the Amendment No. 1 Effective Date.  The Initial
Borrowing Date (as defined in the Existing Credit Agreement) has occurred on or
prior to the Amendment No. 1 Effective Date.

     B.24  Exchange Offer Documents.  True and correct copies of each of the
Exchange Offer Documents (as defined in the Existing Credit Agreement) as of the
Amendment No. 1 Effective Date have been provided to each Current Noteholder.

     B.25  Existing Indebtedness Documents.  As of the Amendment No. 1 Effective
Date, the only credit agreements, loan agreements, indentures, note purchase
agreements, notes, debentures or other instruments or agreements under or in
connection with which Institutional Funded Indebtedness has been issued or is
otherwise outstanding are

          (a)  the Financing Documents,

          (b) the Existing Credit Agreement and the Existing Credit Documents,
     and

          (c)  the SODI Credit Facility.

                                Attachment B-5
<PAGE>
 
                                                                    ATTACHMENT C

                    CONDITIONS TO EFFECTIVENESS OF AMENDMENT

     The Amendment shall become effective, if at all, at such time as

          (a)  the Company and

          (b)  both Current Noteholders

shall have executed and delivered a Confirmation of Consent to Amendment
substantially in the form of Attachment C1 (or in such other form as agreed to
in writing by the Company and the Current Noteholders).  Such execution and
delivery shall constitute conclusive proof of the effectiveness of the
Amendment, and the Amendment shall not (unless otherwise agreed in writing by
the Company and the Current Noteholders) be deemed to be effective unless such
execution and delivery shall have occurred.

     The willingness of the Current Noteholders to execute and deliver such
Confirmation of Consent to Amendment is subject to the following conditions (any
of which may be waived in writing by the Current Noteholders):

     C.1  OPINIONS OF COUNSEL.

     Each Current Noteholder shall have received from

          (a) Hughes Hubbard & Reed, special counsel for the Company, an
     opinion, dated the Amendment No. 1 Effective Date, substantially in the
     form of Attachment C2A and as to such other matters as either Current
     Noteholder may reasonably request, and

          (b) Eric B. Brown, General Counsel of the Company, an opinion, dated
     the Amendment No. 1 Effective Date, substantially in the form of Attachment
     C2B and as to such other matters as either Current Noteholder may
     reasonably request.

This Section C.1 shall constitute direction by the Company to each of such
counsel to deliver such opinions to each Current Noteholder.

     C.2  NO DEFAULT; REPRESENTATIONS AND WARRANTIES TRUE.

     No Default or Event of Default shall exist, and no Default or Event of
Default would exist immediately after (and after giving effect to), the
Amendment.  Each of the warranties and representations set forth in Attachment B
shall be true and correct on the Amendment No. 1 Effective Date.

                                Attachment C-1
<PAGE>
 
     C.3  AUTHORIZATION OF TRANSACTIONS.

     The Company shall have authorized, by all necessary corporate action, the
execution and delivery of this Agreement, each of the Security Documents and the
Intercreditor Agreement and the transactions contemplated by each of such
agreements.

     C.4  INTERCREDITOR AGREEMENT.

     Each of the parties (other than the Current Noteholders) to an
Intercreditor Agreement substantially in the form of Exhibit A (such agreement,
as it may be amended, restated or otherwise modified from time to time, the
"INTERCREDITOR AGREEMENT") shall have executed and delivered such agreement and
each Current Noteholder shall have received a fully executed counterpart
thereof.

     C.5  SECURITY DOCUMENTS.

     Each Current Noteholder shall have received fully executed counterparts of:

          (a) a Stock Pledge Agreement substantially in the form of Exhibit B
     (such agreement, as it may be amended, restated or otherwise modified from
     time to time, the "STOCK PLEDGE AGREEMENT");

          (b) a Note Pledge Agreement substantially in the form of Exhibit C
     (such agreement, as it may be amended, restated or otherwise modified from
     time to time, the "NOTE PLEDGE AGREEMENT"); and

          (c) a separate Subsidiary Guaranty substantially in the form of
     Exhibit D (each such guaranty, as it may be amended, restated or otherwise
     modified from time to time, a "SUBSIDIARY GUARANTY") executed by each of
     Sonat Offshore Norway Inc., Sonat Offshore Ventures Inc., Sonat Turnkey
     Drilling Inc. and Sonat Offshore U.K. Inc.

     C.6  CERTAIN MATTERS RE CREDIT AGREEMENT, ETC.

     Each of the conditions precedent set forth in Section 4 of the Existing
Credit Agreement with respect to the initial borrowings thereunder shall have
been satisfied (or waived, provided that the Company shall have notified you in
writing of any such conditions that have been waived) and the lenders thereunder
shall have advanced the initial loans thereunder.  Without limitation of the
foregoing, the Initial Borrowing Date (as such term is defined in the Existing
Credit Agreement) shall have occurred.

     C.7  EXPENSES.

     All fees and disbursements required to be paid pursuant to Section 6 shall
have been paid in full.

     C.8  PROCEEDINGS SATISFACTORY.

                                Attachment C-2
<PAGE>
 
     All proceedings taken in connection with the execution and delivery of this
Agreement and the other Financing Documents and all documents and papers
relating thereto shall be reasonably satisfactory to each Current Noteholder.
The Current Noteholders and their special counsel shall have received copies of
such documents and papers as any of them may reasonably request in connection
therewith, all in form and substance reasonably satisfactory to the Current
Noteholders.

                                Attachment C-3
<PAGE>
 
                                                                   ATTACHMENT C1


                      CONFIRMATION OF CONSENT TO AMENDMENT
                      ------------------------------------


Date:     September ____, 1996

Re:       Amendment No. 1 to Note Purchase Agreements with respect to
          $30,000,000 6.90% Senior Notes due February 15, 2004 of Transocean
          Offshore Inc. (formerly known as Sonat Offshore Drilling Inc.) (the
          "COMPANY")

     Reference is made to Amendment No. 1 to Note Purchase Agreements, dated as
of September 6, 1996 ("AMENDMENT NO. 1"), among the Company, Principal Mutual
Life Insurance Company ("PRINCIPAL") and Provident Life and Accident Insurance
Company ("PROVIDENT") (Principal and Provident are collectively referred to
herein as the "NOTEHOLDERS").  Pursuant to Amendment No. 1 the Company has
requested that each of the Noteholders consent to the Amendment (as such term is
defined in Section 2 of Amendment No. 1).

     The Company hereby confirms its consent to the Amendment (as such term is
defined in Section 2 of Amendment No. 1).

     In accordance with Section 4.2 and Attachment C of Amendment No. 1, each
Noteholder (a) hereby confirms, based on certain warranties and representations
made, and certain documents delivered, by or on behalf of the Company pursuant
to or otherwise in connection with the transactions referred to in Amendment No.
1, that such Noteholder is satisfied with respect to all proceedings taken in
connection with the execution and delivery of Amendment No. 1 and all documents
and papers relating thereto are reasonably satisfactory to such Noteholder
(provided that this clause (a) shall not be construed as a waiver of any rights
or remedies that either Noteholder may have in the event that any such warranty
or representation shall have been breached) and (b) hereby consents to the
Amendment (as such term is defined in Section 2 of Amendment No. 1).

     Two or more duplicate originals hereof may be signed by the Noteholders and
the Company, each of which shall be an original but all of which together shall
constitute one and the same instrument.  This confirmation may be executed in
one or more counterparts and shall be effective when at least one counterpart
shall have been executed by each Noteholder and the Company, and each set of
counterparts that, collectively, show execution by each Noteholder and the
Company shall constitute one duplicate original.

                                    TRANSOCEAN OFFSHORE INC.



                                    By________________________________

                                     Name:

                                Attachment C1-1
<PAGE>
 
                                     Title:


                                    PRINCIPAL MUTUAL LIFE INSURANCE COMPANY



                                    By________________________________

                                      Name:
                                      Title:



                                    By________________________________

                                      Name:
                                      Title:


                                    PROVIDENT LIFE AND ACCIDENT INSURANCE
                                    COMPANY



                                    By________________________________

                                      Name:
                                      Title:


                                Attachment C1-2
<PAGE>
 
[SIGNATURE PAGE FOR CONFIRMATION OF CONSENT TO AMENDMENT IN CONNECTION WITH
AMENDMENT NO. 1 TO NOTE PURCHASE AGREEMENTS WITH RESPECT TO 6.90% SENIOR NOTES
DUE FEBRUARY 15, 2004 OF TRANSOCEAN OFFSHORE INC. (FORMERLY KNOWN AS SONAT
OFFSHORE DRILLING INC.)]

                                Attachment C1-3
<PAGE>
 
                                                                  ATTACHMENT C2A

              [FORM OF OPINION OF SPECIAL COUNSEL FOR THE COMPANY]

                               Attachment C2A-1
<PAGE>
 
                                                                  ATTACHMENT C2B

              [FORM OF OPINION OF GENERAL COUNSEL OF THE COMPANY]

                               Attachment C2B-1
<PAGE>
 
                                                                       EXHIBIT A

                       [FORM OF INTERCREDITOR AGREEMENT]
<PAGE>
 
                                                                       EXHIBIT B

                        [FORM OF STOCK PLEDGE AGREEMENT]
<PAGE>
 
                                                                       EXHIBIT C

                        [FORM OF NOTE PLEDGE AGREEMENT]
<PAGE>
 
                                                                       EXHIBIT D

                         [FORM OF SUBSIDIARY GUARANTY]
<PAGE>
 
                                                                       EXHIBIT E

                           [COPY OF CREDIT AGREEMENT]