Design of Superhot Geothermal Wells

Abstract

The interest for researching and utilizing superhot geothermal resources has been increasing. The Iceland Deep Drilling Project has led the way, but other projects have followed such as in Japan, New Zealand, Mexico and Italy. Drilling a well into the superhot reservoir and which is suitable for the geothermal fluid expected, is obviously most important for developing this concept. The casings need to be deeper compared to conventional geothermal wells, challenges related to thermal expansion are greater and the fluid chemistry is likely to be more difficult to deal with. An overview is presented of well design in projects where drilling into superhot geothermal resources is planned. The extreme design conditions are discussed along with the associated challenges which need to be solved. The discussion will include some of the lessons learned when drilling and operating wells IDDP-1 and IDDP-2.