Press Releases

TGS expands multi-client 3D seismic library offshore Indonesia

PERTH, AUSTRALIA (21 March 2011) - TGS announces a second multi-client 3D seismic survey in the Tarakan Basin, offshore Northern Indonesia.  The survey, TBB11, will add over 1,820 km2 of new 3D data to the previous survey announced in December 2010.  The TBB11 survey will increase coverage in this area to nearly 3,500 km2.  The data is being acquired by the M/V Seisquest, with acquisition expected to complete in Q2 2011.

The TBB11 survey will be acquired over the southern part of the offshore Tarakan sub-basin, in an underexplored and poor data region.  The area forms part of the extensive Tertiary age play fairway covered by the earlier TBN10 multi-client 3D seismic survey to the north. The new data will assist in improving the understanding of the complex structural and stratigraphic setting of this important oil and gas province and particularly in prospect delineation and well planning.

The TBB11 multi-client 3D survey is supported by industry funding and also supports the Indonesia government's overall objective to attract exploration and raise production levels.

About TGS

TGS provides multi-client geoscience data to oil and gas Exploration and Production companies worldwide. In addition to extensive global geophysical and geological data libraries that include multi-client seismic data, magnetic and gravity data, digital well logs, production data and directional surveys, TGS also offers advanced processing and imaging services, interpretation products, and data integration solutions.

All statements in this press release other than statements of historical fact are forward-looking statements, which are subject to a number of risks, uncertainties and assumptions that are difficult to predict, and are based upon assumptions as to future events that may not prove accurate. These factors include TGS' reliance on a cyclical industry and principal customers, TGS' ability to continue to expand markets for licensing of data, and TGS' ability to acquire and process data product at costs commensurate with profitability. Actual results may differ materially from those expected or projected in the forward-looking statements. TGS undertakes no responsibility or obligation to update or alter forward-looking statements for any reason.

Sven Børre Larsen

Sven Børre Larsen

Chief Financial Officer

Tel: +47 90 94 36 73

Ellen Munkvold

Ellen Munkvold

IR Coordinator

Tel: +47 97 76 26 25