| Title | High-Angle Directional Drilling at Takigami Geothermal Field |
|---|---|
| Authors | Hisashi Jotaki |
| Year | 2000 |
| Conference | World Geothermal Congress |
| Keywords | Takigami, Mwd, High-Angle, Directional Drilling, TR-5, TR-6 |
| Abstract | Ten directional wells which used Measurement While Drilling system (MWD and high torque downhole motor) were drilled by Idemitsu Geothermal Co.,Ltd.since 1993 at Takigami Geothermal Field. Maximum angle of four wells exceeded more than 50 ?. These are what we call High-Angle Directional Drilling for convenience. A well TR-5 was planned to reach a high permeable zone at long distance of the existing reinjection wells and to intersect geological fault at a right angle. This well reached maximum angle to 56?and turned hole azimuth 42?with holding hole angle. A well TR-6 could not have any loss zone originally and was utilized to drill a sidetrack well for another direction at 8- 1/2îopen hole section. This sidetrack well were required a long distance from a original hole and finally reached maximum angle to 66?. We applied a conventional rotary drilling rig with MWD system for these wells and drilled out geological target of them correctly. High-Angle Directional Drilling could expand the drilling area to minimize the pressure interference among wells at a same rig site. And a geological fault and high permeable zone were drilled out at arbitrary direction with accuracy. There were some technical problems at these wells. One of problem was removal of cuttings in 17-1/2î and 12-1/4î hole section. We have coped with this problem by pumping high viscosity mud and short trip of bit. Another problem was that weir-line Electronic Logging could not run 50-60?inclination of open hole section. We will need another Electronic Logging System (Tough Logging Conditioning System) in future. Technical innovation of High-Angle Directional Drilling can expand a production and an injection area over currently in use. Moreover, total wellís cost was drastically cut down by shortening a drilling progress, for we could reduce survey times and trip times and we could increase penetration rate 2- 3 times faster than previous well due to effective utilization of MWD system. |