TGS-NOPEC Q4 and full year 2004 teleconference scheduled

10 January 2005OSE

Naersnes, Norway (10 January, 2005) - Based on preliminary reporting from operating units, TGS management now expects Net Revenues for the Fourth Quarter of 2004 to be approximately USD 58 million, bringing estimated Net Revenues for the full year 2004 to approximately USD 171 million. As a result, full year over year growth from 2003 is now expected to be approximately 25%; significantly above management's previously expressed expectations of 16-17%(including Nu-Tec).

The full 4th Quarter earnings release is scheduled for February 10th, 2005. Management will also issue guidance for 2005 at that time.

TGS-NOPEC offers a telephone conference hosted by CEO Hank Hamilton, VP Business Development John Adamick and CFO Arne Helland today, January 10th at 17,00 Norwegian time (11,00 AM New York time). A Q&A session will follow a short introduction by the management.

Norwegian attendees are invited to call 800 80 119 and international attendees are invited to call +47 23 000 400. Attendees may want to call 5-10 minutes before 17,00 (11,00 AM NY) hours to ensure registration and access. A Q&A session will follow a short introduction, based upon the Presentation issued in the morning. To pose a question, please press *1 A replay of the Conference call will be available shortly after. To access replay of TGS NOPEC`s conference call, dial +47- 22 76 91 21 accountno: 1193 followed by # (pound-sign) press 1 Conferenceno: 193 followed by # (pound-sign) press 1 to play.

TGS-NOPEC Geophysical Company (TGS) is a leading global provider of multi-client geoscientific data, associated products and services to the oil and gas industry. TGS specializes in the creation of non-exclusive seismic surveys worldwide. The company also provides advanced depth imaging solutions and software through its TGS Imaging division. A2D Technologies, a wholly-owned subsidiary, is the energy industry's well log data marketplace offering the largest online database, immediate delivery, conversion services, data management services and worldwide well log data sourcing. The TGS family of companies places a strong emphasis on providing high-quality data and the highest level of service to the industry. 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.

John Adamick
Senior VP, Geological Products and Services
Tel: +1 713 860 2100