TGS Repurchase of Shares

ASKER, NORWAY (26 May 2011) - TGS-NOPEC Geophysical
Company ASA ("TGS") has today purchased 30,000 own
shares at an average price of NOK 145.3849 per
share. Following the purchase, TGS holds 2,011,751
own shares, representing 1.94% of the outstanding
number of shares. The transaction is part of the
share buyback program announced by TGS on 5 May 2011.
The buyback program includes a repurchase of up to
USD 30 million of TGS shares during 2011. During the
period of 6 May to 31 May, the Board has authorized
management to repurchase up to USD 15 million of
shares as part of this program.

Company summary

TGS-NOPEC Geophysical Company (TGS) provides global
geoscience data products and services to the oil and
gas industry for the exploration and delineation of
hydrocarbon reserves. We design and acquire multi-
client data projects worldwide that make up our data
library of seismic, gravity/magnetic and well data,
enhanced by our seismic imaging technology and
regional interpretation expertise. Visit TGS online
at www.tgsnopec.com.

TGS-NOPEC Geophysical Company ASA is listed on the
Oslo Stock Exchange (OSLO:TGS).

For additional information about this news release
please contact:

Kristian Johansen
Chief Financial Officer
Office: +47 667 69931
Cell: +47 47 60 33 34
Email: kristian.johansen@tgsnopec.com

Karen El-Tawil
VP, Business Development
Office: +1 713 860 2102
Cell: +1 713 806 2420
Email: karen.el-tawil@tgsnopec.com