Geothermal Wlll Drilling at Productive Lones in the Kirisima Geotherhal Fields

Abstract

The Ginyu fault, which is the major reservoir in the Kirishima geothermal area, is characterized by a wide of fracture lone and several small fractures. In a geological viewpoint, the Ginyu fault has a echelon arrangement with a width of about 100-200m. So, we need to penetrate through this fault zone. Lost circulation occurs during drilling wells at the zone. We met various problems in drilling through this fault zone, but judging from our experience. it has been solved. We drill through this lone speedy as possible, conseQuently we use fresh water and try to use hot water from discharging wells for drilling fluid. A drilling course crosses the fault plane at right angles because the drilling course is the shortest length.