Reminder of the expiry on 21 September of the offer period for the recommended voluntary exchange offer for all outstanding shares in Magseis Fairfield ASA

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WOULD BE UNLAWFUL

OSLO, Norway (20 September 2022) - Reference is made to the announcements on 29
June 2022 and 24 August 2022, and the offer document dated 24 August 2022 (the
"Offer Document") regarding the recommended voluntary exchange offer by TGS ASA
("TGS" or the "Offeror," ", OSE: TGS) to acquire all outstanding shares (the
"Shares") in Magseis Fairfield ASA ( "Magseis Fairfield," OSE: MSEIS) against an
offer consideration (the "Offer Consideration") of (i) 0.0426 ordinary shares in
TGS and (ii) NOK 2.3592 in cash (the "Offer") per Magseis Fairfield share.

On 6 September 2022, TGS announced that it had received clearance, with the
applicable regulatory waiting periods expiring, from the relevant competition
authorities in the jurisdictions where filings were required, thereby satisfying
a condition to consummation of the Offer.

Reference is also made to the announcement made by Magseis Fairfield on 14
September 2022 regarding the conclusion made by PricewaterhouseCoopers AS, as an
independent expert engaged by Magseis Fairfield, that the Offer, from a
financial point of view, is considered fair to the owners of shares in Magseis
Fairfield.

For further details, please refer to the announcement made available on
https://newsweb.oslobors.no/message/571176

Based on the closing price of the TGS shares of NOK 152.3 as at 19 September
2022, the value of the Offer Consideration was equal to NOK 8.85 per share in
Magseis Fairfield. The share price of Magseis Fairfield on 28 June 2022, the day
immediately preceding the announcement of the Offer, was NOK 5.60.

The period for the Offer (the "Offer Period") will expire on Wednesday, 21
September 2022, at 16:30 (Norwegian time), subject to extensions at the sole
discretion of the Offeror. The complete terms and conditions for the Offer and
procedures for accepting the Offer are set out in the Offer Document. The Offer
can only be accepted based on the Offer Document. Shareholders who want to
accept the Offer must fill out and return the acceptance form, which is included
in the Offer Document, prior to the expiry of the Offer Period.

Acceptances of the Offer already received will remain binding, and there is no
need for shareholders that have already accepted the Offer to take any further
action to confirm their acceptances or otherwise.

Completion of the Offer remains subject to the fulfillment or waiver by the
Offeror of the conditions for the closing of the Offer as set out in Section
3.1 ("Summary of the key terms of the Offer") and Section 3.3.4 ("Conditions for
completion of the Offer") of the Offer Document (including the condition for
acceptance of the Offer by shareholders representing more than 90% of the shares
and votes of Magseis Fairfield on a fully diluted basis), other than regulatory
approvals condition which was announced as satisfied on 6 September 2022.
However, to the Offeror's knowledge, none of the conditions for the Offer that
refer to events that shall or shall not occur are, as of the date hereof, not
satisfied or capable of being satisfied.

The Offer Document and the acceptance form are, subject to regulatory
restrictions in certain jurisdictions, available at www.abgsc.com, where also
contact information can be found for questions related to the Offer and the
acceptance form. The acceptance form includes information on how and where to
submit the form in order to accept the Offer.
Advisors

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

Contact:

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

About TGS
TGS provides scientific data and intelligence to companies active in the energy
sector. In addition to a global, extensive and diverse energy data library, TGS
offers specialized services such as advanced processing and analytics alongside
cloud-based data applications and solutions

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.

The Offer or Consideration Shares referred to in this release have not been and
will not be registered under the United States Securities Act of 1933, as
amended (the "U.S. Securities Act"), or any state securities laws and may not be
offered or sold within the United States or to U.S. Persons unless registered
under the U.S. Securities Act and applicable state securities laws or an
exemption from such registration is available. The information contained in this
announcement is for informational purposes only and does not purport to be full
or complete. TGS does not intend to conduct a public offering in the United
States. The Consideration Shares will only be sold to persons outside the United
States in accordance with Regulation S of the U.S. Securities Act. For U.S.
persons or to persons that are otherwise subject to the securities laws of the
United States, the Consideration Shares will only be sold to "accredited
investors," as defined in Rule 501(a) under Regulation D under the U.S.
Securities Act, pursuant to the exemption from registration provided by Rule
506(c) under such U.S. Securities Act. Copies of this announcement are not
being, and should not be, distributed in or sent into the United States.

In the United Kingdom, this announcement is for distribution only to and is
directed only at persons who (i) have professional experience in matters
relating to investments which fall within Article 19(5) of the Financial
Services and Markets Act 2000 (Financial Promotion) Order 2005 (as amended, the
"Financial Promotion Order"), (ii) are persons falling within Article 49(2)(a)
to (d) ("high net worth companies, unincorporated associations etc") of the
Financial Promotion Order, or (iii) are persons to whom an invitation or
inducement to engage in investment activity (within the meaning of section 21 of
the Financial Services and Markets Act 2000) in connection with the issue or
sale of any securities may otherwise lawfully be communicated or caused to be
communicated (all such persons together being referred to as "relevant
persons").

This announcement is directed only at relevant persons and must not be acted on
or relied on by persons who are not relevant persons. Any investment or
investment activity to which this announcement relates is available only to
relevant persons and will be engaged in only with relevant persons. This
announcement has been prepared on the basis that any offer of securities in any
Member State of the European Economic Area which has implemented the Prospectus
Regulation (EU) (2017/1129, as amended, the "Prospectus Regulation") (each, a
"Relevant Member State") will be made pursuant to an exemption under the
Prospectus Regulation, as implemented in that Relevant Member State, from the
requirement to publish a prospectus for offers of securities. Accordingly, any
person making or intending to make any offer in that Relevant Member State of
securities, which are the subject of the offering contemplated in this
announcement, may only do so in circumstances in which no obligation arises for
TGS to publish a prospectus pursuant to Article 3 of the Prospectus Regulation
or supplement a prospectus pursuant to Article 16 of the Prospectus Regulation,
in each case, in relation to such offer. Neither TGS nor any of the advisors
have authorised, nor do they authorise, the making of any offer of the
securities through any financial intermediary, other than offers made by TGS
which constitute the final placement of the securities contemplated in this
announcement. Neither TGS nor any of the advisors have authorised, nor do they
authorise, the making of any offer of securities in circumstances in which an
obligation arises for the Company to publish or supplement a prospectus for such
offer.

This release contains certain forward-looking statements within the meaning of
the securities laws and regulations of various international, federal, and state
jurisdictions. All statements, other than statements of historical fact,
included herein, including without limitation, statements regarding the Offer or
the future plans and objectives of TGS or Magseis Fairfield are forward-looking
statements that involve risk and uncertainties. There can be no assurances that
such statements will prove to be accurate and actual results could differ
materially from those anticipated in such statements.

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 Offer, TGS or Magseis
Fairfield.

The issue, subscription or purchase of shares in TGS is subject to specific
legal or regulatory restrictions in certain jurisdictions. Neither TGS, Magseis
Fairfield nor their advisors assume any responsibility in the event there is a
violation by any person of such restrictions.