Press Release 15th January 2002

Press Release 15th January 2002

Enzyme Based In-Situ Sand Consolidation Proves Effective In Core Tests

For Immediate Release:

Cleansorb recently completed further successful testing of its patented technology for increasing the consolidation of sandstones. Tests were based on treating outcrop sandstone material with a known, low, unconfined compressive strength. A particle free treatment fluid was flowed into the sandstone cores and shut in. During shut in the fluid underwent controlled, enzyme catalysed chemical changes leading to the deposition of solid material which strengthened the cementation between sand grains. Non-optimised tests increased the unconfined compressive strength of cores by 100 p.s.i., from less than 200 p.s.i. to nearly 300 p.s.i. in a single treatment. Furthermore, the nature of the test procedure is likely to have underestimated the extent of increase in sand consolidation resulting from the treatment.

Earlier tests were conducted on loose sand which was consolidated to give an unconfined compressive strength of about 100 p.s.i.. The latest tests indicate that the process is also effective for increasing the strength of poorly consolidated sandstone cores.

This approach offers the possibility of chemically strengthening poorly consolidated sandstones to prevent sand production during hydrocarbon production. This would reduce or even avoid the need for costly mechanical methods to control sand production. The benefit to operators would be reduced well development and production costs and corresponding increases in asset NPV.

Development work is continuing and Cleansorb is looking for partners to collaborate on developing the technology to the stage of field trials.

For further information please contact:

Dr. Ralph Harris or Dr. Ian McKay

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. This sand consolidation technology 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 deposit solid materials from an initially particle free fluid. This controlled deposition of material within sandstone results in improved cementation between the sand particles and useful increases in consolidation. The chemical and biochemical components of the treatment fluids are environmentally friendly and very low hazard.

2. A catalyst is a compound which promotes a chemical reaction without itself being consumed. The catalyst used in Cleansorb’s sand consolidation 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 Cleansorb’s sand consolidation technology is a biotechnological process it should be clearly distinguished from oilfield well treatments based on bacteria. Using enzymes confers many advantages including a high level of process control, high yield and better thermotolerance. 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 sand consolidation technology Cleansorb offers other enzyme-based processes with applications in oil and gas production. Cleansorb’s Arcasolve^TM acidizing process is already being successfully used in the oilfield by independent and major multinational oil companies. Another process being evaluated for field use is controlled deposition of scale inhibitors within underground reservoirs.