Low Cost Exploration, Testing, and Development of the Chena Geothermal Resource

Abstract

The Chena Hot Springs geothermal field was intensively explored, tested, and developed without a wireline unit between October 2005 and August 2006. Due to the remote location of the project and its small size of 0.4 MW, it was necessary to perform the work without the geothermal industry infrastructure typically utilized in the 48 contiguous states. This could largely be done because some of the wells were capable of artesian flow at below boiling temperatures. The geology, consisting of solid granite below a few tens of feet of alluvium allows for rapid air hammer drilling and minimal casing or tubing requirements. Wells up to 1020 feet deep were logged with precision temperature and pressure instruments under static, flowing, and injecting conditions with hand cranked reels. Low cost well monitoring hardware consisting of used capillary tubing systems and programmable data loggers were obtained and installed by hand for interference testing and monitoring purposes.