04 March 2005
The ClearFRAC* CO2 Fracturing Fluid System Improves Stimulation Results of Tight, Low Pressure and Marginal Reservoirs

HOUSTON, March 4, 2005 - Schlumberger today introduced its new ClearFRAC* CO2 viscoelastic surfactant (VES) system, which extends polymer-free fluid technology to CO2 fracturing applications.

The development of the new robust CO2-based VES fluid system represents a chemistry breakthrough in the carbon dioxide fracturing environment. The fracturing technique is generally used in deeper, lower quality and under-pressured reservoirs, which continue to represent a larger portion of reservoirs requiring stimulation as fields mature and higher quality reservoirs become less abundant.

"Long effective fracture half-length is key to maximizing return on investment (ROI) in tight gas fracturing operations," said Ian Bryant, business development manager, Well Production Services, Schlumberger. "ClearFRAC CO2 accomplishes this with its robust, stable nature and the superior clean-up characteristic of solids-free VES fracturing fluids. It also reduces the propensity for height growth, thus increasing fracture length in the pay zone."

ClearFRAC CO2 enabled a Tulsa-based independent oil and gas exploration company to sand fracture with CO2 down 2-3/8" tubing with the confidence of job placement. This treatment increased fracture half-length and conductivity to maximize production. Additionally, it reduced tubing installation costs by eliminating snubbing operations and packer lubrication, and there was no need to kill the well. This allows a fresh look at old wells with casing problems or previously skipped over sands that require fracture stimulation down tubing for commercial flow rates.

An extension of the Schlumberger ClearFRAC family of VES fracturing fluids, the ClearFRAC CO2 formulation embodies all of the associated attributes, but incorporates a fit-for-purpose surfactant package that addresses the complexities of stabilizing the supercritical CO2.

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About Schlumberger
Schlumberger is the world's leading oilfield services company supplying technology, project management and information solutions that optimize performance for customers working in the oil and gas industry. The company employs more than 52,000 people of over 140 nationalities working in 100 countries, and comprises two business segments. Schlumberger supplies 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. WesternGeco, jointly owned with Baker Hughes, is the world's largest seismic company and provides advanced acquisition and data processing services. In 2004, Schlumberger operating revenue was $11.48 billion. For more information, visit slb.com.

For further information, contact:
Lisa Ann Hofmann
Public Relations Specialist
Schlumberger Oilfield Services
Tel: +1 281 285 7383
Lhofmann@slb.com

Susan Ganz
Media Relations Manager
Schlumberger Oilfield Services
Tel: +281 285 8245
sganz1@slb.com

© Press Release 2006