Field Experiments of Injection in the Otake Geothermal Field, Japan

Abstract

Testing has been in progress since January 1985 in the second Hot Dry Rock reservoir located at Fenton Hill, New Mexico. The results of a 30 day circulation test, conducted in 1986, are reported. The nominal reservoir depth is 3,650 m (11,750 ft) and the mean in situ temperature of the reservoir is 245°C. During the test 37,000 m3 (9.76 million gal) of cold water was injected into the reservoir and hot water was recovered at temperatures ranging up to 192°C. This corresponded to a maximum thermal power output of about 10 MWt. About 66% of the injected water was recovered during this test and a further 20% was recovered during a subsequent vent. The produced fluid's flow rate, temperature and power increased throughout the test. Assuming these trends continue, energy production rates around 12 MWt at the end of one year can be expected. The results of the test show that future efforts for performance improvement need to be focused on the production well.