HOUSTON, July 5, 2011—WesternGeco today announced the start of the Revolution II multiclient survey, which builds on the successful Dual Coil Shooting* multivessel full-azimuth (FAZ) acquisition of Revolution I in the Western Gulf of Mexico acquired in late 2010.

This latest survey is located in the highly prospective Green Canyon area of the Central Gulf of Mexico, where long offsets and FAZ imaging solutions assist our customers in their future production and appraisal drilling plans. The Revolution II multiclient survey will provide FAZ coverage on over 3200 km2 or 140 Outer Continental Shelf (OCS) blocks.

“Traditionally, if clients required multiple azimuths and long offsets, a seismic crew needed to sail multiple times over the same area. With our patented Dual Coil Shooting technique, acquisition has been optimized so that only one seismic crew is needed to capture all azimuths in a single survey,” said Thomas Scoulios, North America region manager, WesternGeco. “In light of the ongoing need to determine reservoirs and their potential more accurately, Dual Coil Shooting is a part of the solution."

Building on multi- and wide-azimuth techniques, Dual Coil Shooting is an advanced method of acquiring full-azimuth, ultra long offset marine seismic data using four vessels following a circular path. This method allows the WesternGeco fleet to focus imaging on specific areas of client interest. Dual Coil Shooting provides better target illumination in challenging environments by enabling greater azimuthal coverage and a higher signal-to-noise ratio. Dual Coil Shooting technology is possible due to the capabilities of the unique WesternGeco Q-Marine* point-receiver marine seismic acquisition system.

WesternGeco will apply advanced seismic data processing techniques to this survey, including true-azimuth 3D GSMP* General Surface Multiple Prediction and anisotropic reverse time migration (RTM).

For more information about the Revolution II multiclient survey, visit www.westerngeco.com/revolution2.

Schlumberger is the world’s leading supplier of technology, integrated project management and information solutions to customers working in the oil and gas industry worldwide. Employing approximately 108,000 people representing over 140 nationalities and working in approximately 80 countries, Schlumberger provides the industry’s widest range of products and services from exploration through production.

Schlumberger Limited has principal offices in Paris, Houston and The Hague and reported revenues of $27.45 billion in 2010. For more information, visit www.slb.com.

###

* Mark of Schlumberger

For further information, contact: