TGS Expands Regional 3D Coverage Offshore Liberia

Asker, Norway (19 October, 2009) - Today TGS-NOPEC Geophysical Company (TGS) confirmed the start up of its next phase of regional multi-client 3D seismic acquisition in offshore Liberia. The new two-thousand square kilometer 3D program expands the existing 9,000 square kilometers of 3D coverage that TGS initiated in late 2008.

Asker, Norway (19 October, 2009) - Today TGS-NOPEC Geophysical Company (TGS) confirmed the start up of its next phase of regional multi-client 3D seismic acquisition in offshore Liberia. The new two-thousand square kilometer 3D program expands the existing 9,000 square kilometers of 3D coverage that TGS initiated in late 2008. The latest Liberia phase will be recorded with long offset acquisition and will incorporate state of the art Prestack Time and PreStack Depth data processing.

TGS expects preliminary data to be available in the third quarter of 2010.

Offshore Liberia has received significant interest in recent months due to the excitement generated by new oil discoveries in both the Gulf of Guinea and Sierra Leone.

"It is exciting to have data in a trend that has recently produced significant oil discoveries in Offshore Africa," commented Kim Abdallah, TGS' VP of New Ventures in Africa and the Middle East. "Our coverage of this emerging oil play will now be more than 14,000 kilometers of multi-client 2D data and 11,000 square kilometers of 3D data." The program is heavily prefunded.

TGS-NOPEC Geophysical Company (TGS) is a principal resource for global geoscientific data products and services in the E&P industry. TGS specializes in the design, acquisition and processing of multi-client seismic surveys worldwide and delivers advanced high performance seismic imaging and software solutions. The Company also provides the world's largest online well-log database, well data management services, multi-client interpretive products and subsurface consulting services to industry. The suite of integrated exploration data products available from TGS is distinctive and unmatched. The Company philosophy is to create unique high-quality data collected in the right place at the right time.

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 products 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.

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