2004 Volume 26 Issue 2 Pages 165-170
The Yanaizu-Nishiyama geothermal field is located on 20 km west of the Aizu wakamatsu city, Fukushima prefecture. The commercial power generation with 65 MW was started in 1995. After three years later, however, the steam production started to decline seriously to the bottom electricity of 38 MW in 2000. With the drilling effort, the steam production turned to go up gradually, and it seems to be stabilized at 45 MW. Through the micro-gravity study, the large pressure drawdown in the central part of the production zone due to excess production and the importance to re-inject water into the reservoir to maintain the reservoir pressure were pointed out. In the recent years, a few efforts of artificial recharge were started.