TGS-NOPEC Q1-2005 webcast and teleconference

27 April 2005OSE

TGS-NOPEC will publish its Q1 2005 results before 09,00 Norwegian time on the morning of May 4th, 2005. At the same time, a recorded presentation with Audio by CEO Hank Hamilton and CFO Arne Helland will be made available at

The slides from the presentation will also be available in PDF format at both the TGS-NOPEC and Oslo Stock Exchange websites.

CEO Hank Hamilton, VP Business Development John Adamick and CFO Arne Helland will also host a conference call on May 4th. at 15,00 Norwegian time (9,00 AM New York time). 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 15,00 (9,00 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.

Please call Arne Helland at +47 31 29 20 00 / +47 91 88 78 29 should you need more information about this.

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