NOT FOR PUBLICATION, DISTRIBUTION OR RELEASE, DIRECTLY OR INDIRECTLY, IN OR INTO
THE UNITED STATES, CANADA, JAPAN OR AUSTRALIA OR ANY OTHER JURISDICTION INTO
WHICH PUBLICATION OR DISTRIBUTION WOULD BE PROHIBITED BY APPLICABLE LAW.

Contemplated sale of shares in TGS-NOPEC Geophysical Company ASA

Altor Invest 1 AS and Altor Invest 2 AS (both companies part of Altor Fund IV
and together referred to as the “Seller”) have retained ABG Sundal Collier ASA
and Carnegie AS to explore the sale of up to 4,480,128 shares in TGS-NOPEC
Geophysical Company ASA (the "Company" or "TGS") through an accelerated
bookbuilding process (the "Placement"). The Placement represents approximately
3.77% of the outstanding shares in the Company. 

The final placement size and price per share will be determined through an
accelerated bookbuilding process to Norwegian and international investors. The
Seller reserves the right, at its own discretion, to reduce the number of offer
shares or to sell no shares at all, depending on the price and the demand for
shares. The bookbuilding period commences immediately and may close at any time.


The Seller is not a primary insider in the Company. Assuming that all shares in
the Placement are sold, the Seller will not own any shares in the Company. 

IMPORTANT NOTICE

The distribution of this announcement and the offer and sale of the shares in
certain jurisdictions may be restricted by law. The shares may not be offered to
the public in any jurisdiction in circumstances which would require the
preparation or registration of any prospectus or offering document relating to
the shares in such jurisdiction. No action has been taken by the managers or any
of its affiliates that would permit an offering of the shares or possession or
distribution of this announcement or any other offering or publicity material
relating to such securities in any jurisdiction where action for that purpose is
required. Persons into whose possession this announcement comes are required to
inform themselves about and to observe any such restrictions. Any failure to
comply with these restrictions may constitute a violation of the securities laws
of any such jurisdiction.

This press release is for information purposes only and does not constitute or
form a part of an offer to sell or a solicitation of an offer to purchase any
security of the Company in the United States or in any other jurisdiction where
such offer or solicitation is unlawful. The securities of the Company described
in this press release have not been and will not be registered under the U.S.
Securities Act of 1933, as amended (the "Securities Act"), or any applicable
state or foreign securities laws and may not be offered or sold in the United
States absent registration or an exemption from the registration requirements of
the Securities Act. There will be no public offering of securities in the United
States.