Coiled Tubing Drilling Using Supercritical Carbon Dioxide--Tempress Technologies, Inc., 19308 68th Avenue South, , Kent, WA 98032-1192; (253) 872-1980
Dr. Jack J. Kolle, Principal Investigator
Dr. Edward Bohn, Business Official
DOE Grant No. DE-FG03-98ER82696
Amount: $74,924

Underbalanced drilling (a standard technique which utilizes insertion of a pressurized fluid, through rigid pipe, to the bottom of a borehole to force drilled material to the surface) is limited to low pressure formations with low risk of uncontrolled well flows or unstable shales. Drilling with a flexible tube that may be coiled on a spool allows lateral drilling with surface pressure control equipment, but the penetration rate and reach are low. This project will develop a technique for coiled tubing drilling using carbon dioxide as the drilling fluid. The ultimate objective is a coiled tubing drilling system capable of rapid and safe slimhole drilling of extended reach laterals in pressurized formations. Small scale pressure drilling tests will be carried out using supercritical carbon dioxide. The tests will examine the effect of fluid pressures on jet erosion and mechanical drilling of shale. The results will be used to define a coiled tubing drilling system operating with carbon dioxide.

Commercial Applications and Other Benefits as described by the awardee: Coiled tubing drilling with carbon dioxide will provide all of the benefits of underbalanced drilling -- fast penetration, extended reach and minimal formation damage--while maintaining well control. It will allow fast, safe drilling of pressurized formations and hydrateable shales.