抄録
The geothermal exploration at the Takigami area started in 1979 with various surveys and drill holes. The 25 MW Takigami power plant was opened in November 1996. Since the production rate of steam is very stable, the power plant continues the cost effective generation. On the other hand, injection rate is still declining with 10∼25% a year probably due to the silica-scaling. To keep the effective generation, much effort has been conducted to solve the problems as follows.
1) Engineering study of scale inhibition of injection in wells and also in fracture with reservoir simulation including chemical components.
2) High-angle directional-drilling with MWD system to reduce the drilling cost and site area.
3) Utilization of separated hot water.
4) Improvement of operation system and technique.
