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                                 SCHEDULE 13D/A
                                (Amendment No. 1)
                   Under the Securities Exchange Act of 1934*

                           PETROLEUM GEO-SERVICES ASA
   --------------------------------------------------------------------------
                                (Name of Issuer)


               Ordinary Shares, Nominal Value NOK5 per Share, and
        American Depositary Shares, Each Representing One Ordinary Share
    -------------------------------------------------------------------------
                         (Title of Class of Securities)


                     716597109 (American Depositary Shares)
  ---------------------------------------------------------------------------
                                 (CUSIP Number)


                                 Michel Ponthus
                         Senior Executive Vice President
                           Finance and Human resources
                           and Chief Financial Officer
                        Compagnie Generale de Geophysique
                               1, rue Leon Migaux
                                   91341 Massy
                                     France
                                (33-1) 64 47 3000
  ----------------------------------------------------------------------------
                  (Name, Address and Telephone Number of Person
                Authorized to Receive Notices and Communications)


                                  June 18, 2003
 -----------------------------------------------------------------------------
                          (Date of Event which Requires
                            Filing of this Statement)


If the filing  person has  previously  filed a statement on Schedule 13G to
report the  acquisition  that is the subject of this Schedule 13D, and is filing
this schedule  because of ss.ss.  240.13d-1(e),  240.13d-1(f)  or  240.13d-1(g),
check the following box:

NOTE:  Schedules  filed in paper format shall include a signed original and
five copies of the  schedule,  including all  exhibits.  See Rule  240.13d-7 for
other parties to whom copies are to be sent.

* The  remainder  of this cover  page  shall be filled out for a  reporting
person's  initial  filing on this  form with  respect  to the  subject  class of
securities,  and for any subsequent amendment containing information which would
alter disclosures provided in a prior cover page.

     The  information  required on the remainder of this cover page shall not be
deemed to be "filed"  for the purpose of Section 18 of the  Securities  Exchange
Act of 1934 ("Act") or otherwise  subject to the  liabilities of that section of
the Act but shall be subject to all other  provisions of the Act  (however,  see
the Notes).


                           SCHEDULE 13D

--------------------------------------------------------------------------------
CUSIP No.         716597109 (American depositary shares)
--------------------------------------------------------------------------------


------- -----------------------------------------------------------------------
1       NAMES OF REPORTING PERSON
        I.R.S. IDENTIFICATION

       Compagnie Generale de Geophysique           I.R.S. #  Not Applicable
-------------------------------------------------------------------------------
----------- ------------------------------------------------------------------
2       CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP (See Instructions)(a)_
                                                                           (b)_
-------------------------------------------------------------------------------
------- -----------------------------------------------------------------------
3       SEC USE ONLY
-------------------------------------------------------------------------------
------- -----------------------------------------------------------------------
4       SOURCE OF FUNDS (See Instructions)
        WC
-------------------------------------------------------------------------------
------- -----------------------------------------------------------------------
5       CHECK IF DISCLOSURE OF LEGAL PROCEEDING IS REQUIRED PURSUANT TO ITEMS
        2(d) or 2(e)
-------------------------------------------------------------------------------
------- -----------------------------------------------------------------------
6       CITIZENSHIP OR PLACE OF ORGANIZATION
        Republic of France
------------------------------- --------- --------------------------------------
                 7      SOLE VOTING POWER
                        7,757,400
              --------- --------------------------------------------------------
 NUMBER OF       8      SHARED VOTING POWER
   SHARE                0
BENEFICIALLY --------- ---------------------------------------------------------
OWNED BY EACH    9     SOLE DISPOSITIVE POWER
 REPORTING             7,757,400
PERSON WITH --------- ----------------------------------------------------------

              10      SHARED DISPOSITIVE POWER
                      0
           --------- ----------------------------------------------------------
11      AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON
        7,757,400
--------------------------------------------------------------------------------
------- ------------------------------------------------------------------------
12      CHECK IF THE AGGREGATE AMOUNT IN ROW (11) EXCLUDES CERTAIN SHARES
        (See Instructions)
--------------------------------------------------------------------------------
----------- --------------------------------------------------------------------
13      PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW (11)
        7.5%
--------------------------------------------------------------------------------
------- ------------------------------------------------------------------------
14      TYPE OF REPORTING PERSON (See Instructions)
        CO
------- ------------------------------------------------------------------------


Item 1.  Security and Issuer.

     This Amendment No. 1 amends the statement on Schedule 13D (such schedule as
amended  being the  "Schedule  13D")  originally  filed on  October  4, 2002 and
relating to the ordinary  shares,  nominal value NOK5 per share (the  "Shares"),
and the American depositary shares, each representing one Share (the "ADSs") and
evidenced by American  depositary  receipts,  of Petroleum  Geo-Services  ASA, a
Norwegian  allmennaksjeselskap  (the "Company"),  and is being filed pursuant to
Rule 13d-2 of the Exchange Act. The address of the principal  executive  offices
of the Company is Strandveien 4, N-1366 Lysaker,  Kingdom of Norway.  References
herein to  Shares  include  references  to ADSs  unless  the  context  otherwise
requires.  Capitalized  terms not  otherwise  defined  herein have the  meanings
ascribed to them in the Schedule 13D.

Item 2. Identity and Background.

     This  statement  is being filed by  Compagnie  Generale de  Geophysique,  a
French  societe  anonyme (the  "Reporting  Person").  The list of the  executive
officers and directors of the Reporting Person attached hereto as Schedule I and
incorporated herein by reference contains the following information with respect
to each such person:  (i) name, (ii) business  address,  (iii) present principal
occupation  or  employment  and name,  principal  business  and  address  of any
corporation or other organization in which such employment is conducted and (iv)
citizenship.

     The Reporting Person is a societe anonyme duly incorporated  under the laws
of the Republic of France.

     The Reporting  Person  participates  in the oilfield  services  industry by
providing  seismic data  acquisition,  processing  and  geoscience  services and
equipment to clients in the oil and gas exploration and production business.

     The address of the principal business and principal office of the Reporting
Person is 1, rue Leon Migaux, 91341 Massy, France.

     Neither the Reporting Person nor, to the best of its knowledge,  any of the
persons named in Schedule I has, during the last five years, been convicted in a
criminal  proceeding  (excluding  traffic  violations or similar  misdemeanors).

     Neither the Reporting Person nor, to the best of its knowledge,  any of the
persons named in Schedule I has,  during the last five years,  been a party to a
civil proceeding of a judicial or administrative body of competent  jurisdiction
and as a result of such  proceeding  was or is subject to a judgment,  decree or
final  order  enjoining  future  violations  of,  or  prohibiting  or  mandating
activities subject to, federal or state securities laws or finding any violation
with  respect  to such  laws.

Item 3.  Source  and  Amount  of  Funds  or Other Consideration.

     No Amendment.

Item 4.  Purpose of Transaction.

     Item 4 is amended to add the following final paragraph:

     As a significant shareholder of the Company since September 26, 2002 with a
7.5% equity stake,  the Reporting  Person has given its support to the financial
restructuring plan as set forth in a Plan Support Agreement dated June 18, 2003.
This support is materialized by the participation of the Reporting Person to the
group of "supporting  shareholders" who have committed to jointly acquire 30% of
the post-restructuring  equity of the Company for a global amount of $85 million
(of which $22  million  for the  Reporting  Person and $60  million  for another
shareholder of the Company  unaffiliated with the Reporting Person). 75% of this
30% tranche  will be proposed to the  Company's  shareholders  pro-rata to their
share ownership at a date to be determined,

                                     - 2 -



therefore  potentially  reducing the amount  guaranteed to the  "supporting
shareholders"  to a minimum 25% of this tranche  (corresponding  to $5.5 million
for the Reporting Person).  Upon completion of this process  anticipated by fall
2003,  the Reporting  Person's  stake in the Company will therefore be comprised
between 2.7% and 8.1%.

Item 5. Interest in Securities of the Issuer.

     (a) No Amendment.

     (b) No amendment.

     (c) No  transactions in Shares of the Company were effected during the last
sixty days by the  Reporting  Person or any of the persons set forth in Schedule
I.

     (d) No Amendment.

     (e) No Amendment.

Item 6.  Contracts,  Arrangements,  Understandings  or  Relationships  With
         Respect to the Securities of the Issuer.

     No Amendment.

Item 7.  Material to be Filed as Exhibits

      Exhibit No.     Description

      10.1            Plan Support Agreement (including the PGS Summary of
                      Proposed Terms for Balance Sheet Restructuring), dated as
                      of June 18, 2003, among the  Company and certain of PGS'
                      bank lenders, bondholders and shareholders (including the
                      Reporting Person).

                                     - 3 -

                                   SIGNATURES

     After reasonable  inquiry and to the best of our knowledge and belief,  the
undersigned  certify that the  information  set forth in this statement is true,
complete and correct.

Dated: June 27, 2003          COMPAGNIE GENERALE DE GEOPHYSIQUE



                              By:   /s/ Christophe Pettenati-Auziere
                                 ---------------------------------------------
                                    Name:    Christophe Pettenati-Auziere
                                    Title:   Senior Executive Vice President
                                             (Strategy, Planning and Control)




                                                                      SCHEDULE I

     Set forth below is the name,  position and present principal  occupation or
employment of each of the executive officers and directors of Compagnie Generale
de Geophysique (the "Reporting  Person") as well as, when such present principal
occupation or employment is not with the Reporting Person,  the name,  principal
business  and address of any  corporation  or other  organization  in which such
employment is conducted.  Except as otherwise indicated, the business address of
each of such persons is 1, rue Leon Migaux,  91341  Massy,  France,  and each of
such  persons  is a citizen  of the  Republic  of  France.  Except as  otherwise
indicated,  no such person owns  beneficially any ordinary share,  nominal value
NOK5 (a  "Share")  and/or  American  depositary  share (an  "ADS") of  Petroleum
Geo-Services ASA (the "Company").

            Executive Officers and Directors of the Reporting Person
            --------------------------------------------------------

--------------------------------------------------------------------------------
              NAME              PRESENT PRINCIPAL OCCUPATION IN ADDITION
                                TO POSITION WITH THE REPORTING PERSON
----------------------------- --------------------------------------------------
----------------------------- --------------------------------------------------
Robert Brunck                 Chairman and Chief Executive Officer of the
                              Reporting Person.
----------------------------- --------------------------------------------------
----------------------------- --------------------------------------------------
Gerard Chambovet              Senior Executive Vice President of the Reporting
                              Person (Services).
----------------------------- --------------------------------------------------
----------------------------- --------------------------------------------------
Thierry Le Roux               Senior Executive Vice President of the Reporting
                              Person (Products).
----------------------------- --------------------------------------------------
----------------------------- --------------------------------------------------
Michel Ponthus                Senior Executive Vice President (Finance and Human
                              Resources) and Chief
                              Financial Officer of the Reporting Person.
----------------------------- --------------------------------------------------
----------------------------- --------------------------------------------------
Christophe Pettenati-Auziere  - Senior Executive Vice President of the Reporting
                                Person (Strategy, Planning and Control).
                              - Number of ADSs of the Company beneficially
                                owned:  1,000.
----------------------------- --------------------------------------------------
----------------------------- --------------------------------------------------
Gerard Fries                    - Director of the Reporting Person;
                                - Senior Executive Vice President of Institut
                                  Francais du Petrole 1, avenue du Bois Preau
                                  92500 Rueil Malmaison, France.
----------------------------- --------------------------------------------------
----------------------------- --------------------------------------------------
Robert Castaigne                - Director of the Reporting Person;
                                - Chief Financial Officer and member of the
                                  Executive Committee of TotalFinaElf
                                  2, place de la Coupole
                                  La Defense 6
                                  92078 Paris La Defense Cedex, France.
----------------------------- --------------------------------------------------
----------------------------- --------------------------------------------------
Jean Dunand                     Director of the Reporting Person.
----------------------------- --------------------------------------------------
----------------------------- --------------------------------------------------
Olivier Appert                 - Director of the Reporting Person;
                               - President of the Institut Francais du Petrole
                                 1, avenue du Bois Preau
                                 92500 Rueil Malmaison, France.
----------------------------- --------------------------------------------------
----------------------------- --------------------------------------------------
Yves Lesage                      Director and Honorary Chairman of the Reporting
                                 Person.
----------------------------- --------------------------------------------------
----------------------------- --------------------------------------------------
John MacWilliams(1)            - Director of the Reporting Person;
                               - Partner of JP Morgan Partners
                                 1221 Avenue of the Americas
                                 New York, New York  10020, U.S.A.
----------------------------- --------------------------------------------------
----------------------------- --------------------------------------------------
Christian Marbach              Director of the Reporting Person.
----------------------------- --------------------------------------------------
----------------------------- --------------------------------------------------
Daniel Valot                   - Director of the Reporting Person;
                               - Chairman of the Management Board of
                                 Technip-Coflexip
                                 170, place Henri Regnault
                                 92973 Paris La Defense Cedex, France.
----------------------------- --------------------------------------------------
----------------------------- --------------------------------------------------
Robert Semmens(1)              - Director of the Reporting Person;
                               - Independent consultant.
----------------------------- --------------------------------------------------
-----------------
(1) U.S. citizen.