Press release February 2003

Press release February 2003

Arcasolve™ approved for north sea use and placed in lowest hazard category

For immediate release:

Following recent successful Arcasolve™ well treatments in the North Sea with major operating companies Cleansorb is pleased to announce full registration of its Arcasolve™ range of well treatment chemicals for offshore use.

The low toxicity, low environmental impact characteristics of Arcasolve™ are reflected by all the chemicals achieving either OCNS Category E or CHARM Gold band status. This, combined with the low hazard nature of Arcasolve™, ensures it is particularly suited to handling and use offshore or in remote locations.

The offshore work builds on the onshore success, where Arcasolve™ is being used as a single stage combined acidising and polymer breaker treatment for effective drilling mud cake damage removal in new and existing oil or gas production wells and water injection wells.

For further information please contact:

Cleansorb Ltd, Surrey Technology Centre , 40 Occam Road, Surrey Research Park, Guildford, Surrey GU2 7YG, U.K.

Tel. ++44 (0)1483 295090

Fax. ++44 (0)1483 845358

Notes for editors:

1. Arcasolve^TM has been developed by Cleansorb Limited, based at the Surrey Research Park in Guildford, Surrey, UK. The process combines enzymes (biological catalysts) with suitable chemicals to generate organic acid at a controlled rate in the fluid injected into the wellbore or formation. The bulk of the acid is produced after placement of the fluid, permitting the efficient and even delivery of acid to the target zones maximizing the production rate of the well and its value to the operator. Arcasolve^TM is environmentally friendly and very low hazard. Conventional acids are hazardous in use and generally require the use of toxic corrosion inhibitors.

2. A catalyst is a compound that promotes a chemical reaction without itself being consumed. The catalyst used in the Arcasolve^TM process is an enzyme. Enzymes are chemical compounds found in nature. They are however single chemical compounds which can be manufactured to the usual standards of purity of industrial chemicals.

3. Although Arcasolve ^TMis a biotechnological process it should be clearly distinguished from previous stimulation processes based on bacteria. Using enzymes confers many advantages including a high level of process control, high yield and better thermo tolerance. Enzyme based systems are also particulate free.

4. Cleansorb Limited, based at the Surrey Research Park, Guildford, Surrey, UK, is a privately owned biotechnology company which specializes in developing enzyme-based processes which assist oil and gas production. Contact: Ian McKay or Ralph Harris, Tel. ++44 (0) 1483 295090 Fax. ++44 (0) 1483 845358.

5. In addition to Arcasolve^TM, Cleansorb has other award winning enzyme-based processes under development that allow the controlled deposition of scale inhibitors and gels, minerals or resins in underground reservoirs. These have a number of applications in oil and gas production.