11 November 2004
Q-Marine 4D Survey to Image Marlim Complex

HOUSTON - WesternGeco announced today that it was selected by Petrobras to acquire and process Q-Marine* seismic data over the Marlim complex, offshore Brazil. The 1520-square-kilometer, five-month survey began in October.

The Marlim complex, comprising the Marlim, Marlim East and Marlim South fields, is the largest deepwater producer of oil and gas in the world.

The Q-Technology vessel Western Pride, towing 10 x 6000-meter cables with 50-meter streamer separation, will be used to acquire the Marlim survey. This survey will comprise the baseline against which future surveys will be compared to monitor fluid movement for reservoir characterization and asset management.

"Only Q-Marine offers the required level of repeatability through high-fidelity calibrated source and single sensor acquisition, together with Q-Marine's active streamer steering. This is the ideal technology for this survey area, which is highly obstructed with a variety of production facilities including tankers, FPSOs, tension leg platforms and anchored semi-submersibles," said Marcus Ganz, manager, WesternGeco South America. "With Q-Marine active streamer steering, the streamers will safely pass much closer to the obstructions, minimizing the amount of undershoot required."

Q* is the WesternGeco proprietary suite of advanced seismic technologies for enhanced reservoir location, description, and management. For additional information on Q-Marine, the world's only fully calibrated, point-receiver marine seismic acquisition and processing system, as well as Q-Land* and Q-Seabed*, visit www.westerngeco.com/Q-Technology.

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About Schlumberger
Schlumberger is the world's leading oilfield services company supplying a wide range of products and services from formation evaluation through directional drilling, well cementing and stimulation, well completions and productivity to consulting, software, information management and IT infrastructure services that support core industry operational processes. Today, the company employs more than 50,000 people of over 140 nationalities working in 100 countries. Schlumberger also manages WesternGeco, jointly owned with Baker Hughes, which is the world's largest seismic company and provides advanced acquisition and data processing services. In 2003, Schlumberger operating revenue was $10.1 billion. For more information, visit slb.com.

For further information, contact:
Susan Ganz
Media Relations Manager
Schlumberger Oilfield Services
Tel: +1 281 285 8245
sganz1@slb.com

Press Release 2006