NOT FOR RELEASE, PUBLICATION OR DISTRIBUTION, IN WHOLE OR IN PART, DIRECTLY OR
INDIRECTLY, INTO OR WITHIN AUSTRALIA, CANADA, HONG KONG, JAPAN, SOUTH AFRICA,
THE UNITED STATES OR ANY OTHER JURISDICTION IN WHICH THE DISTRIBUTION OR RELEASE
WOULD BE UNLAWFUL

Oslo, Norway (20 December 2022) - Reference is made to the mandatory offer dated
10 November 2022 (the "Mandatory Offer" or the "Offer") to acquire all shares in
Magseis Fairfield ASA ("Magseis Fairfield" or the "Company", OSE: MSEIS) that
are not already owned by TGS ASA ("TGS" or the "Offeror", OSE: TGS) at an offer
price of NOK 8.08 in cash per share.

The period for acceptance (the "Acceptance Period") will expire on Wednesday 21
December 2022 at 16:30 (CET). The complete terms and conditions for the
Mandatory Offer and procedures for accepting the Mandatory Offer are set out in
the mandatory offer document prepared by TGS dated 10 November 2022 (the
"Mandatory Offer Document"), which has been approved by the Oslo Stock Exchange
in its capacity as take-over supervisory authority. The Mandatory Offer can only
be accepted based on the Mandatory Offer Document. Shareholders who want to
accept the Offer must fill out and return the acceptance form which is included
in the Mandatory Offer Document, prior to the expiry of the Acceptance Period.
 
Acceptances of the Mandatory Offer already received will remain binding and
there is no need for shareholders that have already accepted the Mandatory Offer
to take any further action to confirm their acceptances or otherwise.

The Mandatory Offer Document and the acceptance form are, subject to regulatory
restrictions in certain jurisdictions, available at www.abgsc.no, and may be
obtained free of charge during ordinary business hours at the offices of the
receiving agent, ABG Sundal Collier ASA, Ruseløkkveien 26, 0251 Oslo, Norway.
The acceptance form includes information on how and where to submit the form in
order to accept the Mandatory Offer.

Advisors: 

ABG Sundal Collier ASA acts as financial advisor to TGS and receiving agent for
the Mandatory Offer. Advokatfirmaet Schjødt AS acts as legal advisor to TGS.
Arctic Securities AS acts as financial advisor and Advokatfirmaet Thommessen AS
acts as legal advisor to Magseis Fairfield. 

Contacts: 

TGS: Sven Børre Larsen, CFO 
Tel: +47 909 43 673
Email: investor@tgs.com 

Important notice: 

It may be unlawful to distribute this announcement in certain jurisdictions.
This announcement is not for distribution in Australia, Canada, the Hong Kong
special administrative region of the People's Republic of China, Japan, South
Africa, the United States or to any other jurisdiction where such distribution
would be unlawful. The information in this announcement does not constitute an
offer of securities for sale in such jurisdictions. Persons into whose
possession this release comes should inform themselves about and observe any
such restrictions. Any failure to comply with these restrictions may constitute
a violation of the securities laws of any such jurisdiction. This announcement
does not constitute an offer for sale of, or a solicitation of an offer to
purchase or subscribe for, any securities in the United States. 

Neither TGS, Magseis Fairfield nor any of their advisors and/or any of their
affiliates or any of their respective directors, officers, employees, advisers,
agents or any other person(s) accept any responsibility or liability whatsoever
for, or make any representation or warranty, express or implied, as to the
accuracy, completeness or fairness of the information or opinions in this
announcement (or whether any information has been omitted from this
announcement) or any other information relating the Mandatory Offer, TGS or
Magseis Fairfield.

Mandatory Offer Restrictions

The distribution of the Mandatory Offer Document and the making of the Mandatory
Offer may in certain jurisdictions ("Restricted Jurisdictions") be restricted by
law. Therefore, persons obtaining the Mandatory Offer Document or into whose
possession the Mandatory Offer Document otherwise comes, are required to, and
should inform themselves of and observe, all such restrictions. The Offeror and
the Receiving Agent do not accept or assume any responsibility or liability for
any violation by any person whomsoever of any such restriction.

The Mandatory Offer Document is not directed to persons whose participation in
the Mandatory Offer requires that further offer documents are issued or that
registration or other measures are taken, other than those required under
Norwegian law, provided, however, that the Mandatory Offer is made to Magseis
Fairfield shareholders resident in the United States, see further below. No
document or materials relating to the Mandatory Offer may be distributed in or
into any jurisdiction where such distribution or offering requires any of the
aforementioned measures to be taken or would be in conflict with any law or
regulation of such a jurisdiction. In the event of such distribution or offering
still being made, an Acceptance Form sent from such a country may be
disregarded.

The Mandatory Offer Document does not represent an offer to acquire or obtain
securities other than Magseis Fairfield shares. The Mandatory Offer is not open
to any Magseis Fairfield shareholder in any jurisdiction in which it is unlawful
for any person to receive or accept the Mandatory Offer. No action has been
taken to permit the distribution of the Mandatory Offer in any jurisdiction
where action would be required for such purposes (except Norway).

The Mandatory Offer is not being made and will not be made, directly or
indirectly, in or into the Restricted Jurisdictions. The Mandatory Offer
Document, and any and all materials related thereto, should not be sent or
otherwise distributed in or into the Restricted Jurisdictions, and the Mandatory
Offer cannot be accepted by any such use, means or instrumentality, in or from
within Restricted Jurisdictions. Accordingly, copies of the Mandatory Offer
Document and any related materials are not being, and must not be, sent or
otherwise distributed in or into or from any Restricted Jurisdiction or, in
their capacities as such, to custodians, trustees or nominees holding shares in
Magseis Fairfield for persons in any Restricted Jurisdictions, and persons
receiving any such documents (including custodians, nominees and trustees) must
not distribute or send them in, into or from any Restricted Jurisdiction. Any
purported acceptance of the Mandatory Offer resulting directly or indirectly
from a violation of these restrictions will be invalid.

Notice to U.S. Investors

The Mandatory Offer is being made for securities of a Norwegian company, and
Magseis Fairfield Shareholders in the United States should be aware that the
Mandatory Offer Document and any other documents relating to the Mandatory Offer
have been or will be prepared in accordance with Norwegian law, format and
style, all of which differ from those in the United States. All financial
information that is included in the Mandatory Offer Document, or any other
documents relating to the Mandatory Offer, have been or will be prepared in
accordance with the International Financial Reporting Standards as adopted by
the EU (the "IFRS") and may not be comparable to financial statements of
companies in the United States or other companies whose financial statements are
prepared in accordance with U.S. generally accepted accounting principles.
Neither the U.S. Securities and Exchange Commission ("SEC") nor any U.S. state
securities commission has approved or disapproved the Mandatory Offer or passed
any comment upon the adequacy or completeness of the Mandatory Offer Document.
Any representation to the contrary is a criminal offence in the United States.
Nothing in the Mandatory Offer Document shall be deemed an acknowledgement that
any SEC filing is required or that an offer requiring registration under the
U.S. Securities Act may ever occur in connection with the Mandatory Offer. The
Mandatory Offer will be made in the United States pursuant to Section 14(e) of,
and Regulation 14E under, the U.S. Securities Exchange Act of 1934, as amended
(the "U.S. Exchange Act"), and otherwise in accordance with the requirements of
Norwegian law. Accordingly, the Mandatory Offer will be subject to disclosure
and other procedural requirements, including with respect to withdrawal rights
that are different from those applicable under United States domestic tender
offer procedures and law, as described elsewhere in the Mandatory Offer
Document.