Raytheon Downhole Information System: Electromagnetic Lithospheric Information System for Geothermal Drilling. Interim Report

摘要

The Raytheon Downhole Information System (RDIS), which is designed to reduce the drilling cost and increase the energy yield of deep geothermal wells, is described. The RDIS consists of a downhole sensor package located just above the drill bit, a telemetry link in the drill string, and a well head data management and control system. The RDIS assists the driller to speed drilling, select the best depth locations for geothermal energy exploitation, and protect against catastrophes. Cost savings for drilling optimization are estimated at 24% for a 15,000 foot well under routine conditions. Even greater savings may accrue for catastrophe prevention. The telemetry link operates at an extremely low electromagnetic carrier frequency because propagation occurs directly through the earth. The resulting bit rates, 1 to 10 Hz, are adequate, however, because drilling is characterized by very long time constants, and sensor package data is efficiently preprocessed downhole. Sensors and telemetry units must withstand temperatures in excess of 200 exp 0 C. Studies and tests suggest that a goal of 275 exp 0 C is achievable with modest improvement in available solid state circuitry and power supplies. A three phase development plan is presented to provide a first commercial system in 26 months after start of Phase I field tests. (ERA citation 04:013092)