Advanced Drilling System for Drilling Geothermal Wells - An Estimate of Cost Savings

Abstract

An advanced geothermal drilling system (AGDS) has previously been proposed. This system concept is based on the use of a percussion drilling motor and dual wall reverse circulation drill strings. The concept is based on a merger of the deep drilling capabilities of conventional petroleum drilling equipment with mining, water well, and civil engineering drilling technologies. The use of percussion drilling is introduced to provide significantly increased penetration rates in the harder geothermal reservoir rocks, as compared to roller-cone bits and rotary table drives. The dual wall drillstring provides solutions to lost circulation control(the major problem frequently encountered in geothermal drilling).