The US Hot Dry Rock Program - 20 Years of Experience in Reservoir Testing

Abstract

During 25 years of research on Hot Dry Rock (HDR) geothermal energy at Los Alamos National Laboratory, no obstacle has yet been found that would preclude its ultimate development into a major new energy source for mankind. Techniques for efficiently extracting the thermal energy contained in the vast worldwide resource of deep, hot crystalline rock have been under investigation since 1973 at the Laboratoryís Fenton Hill HDR test site in north-central New Mexico. From the engineering and flow testing of two successive deep HDR reservoirs, we have gained a clear understanding of how to create such man-made geothermal systems. Also, we have learned a great deal about the rock mass deformation and joint flow within the pressure-dilated region comprising the HDR reservoir at pressures well in excess of the minimum earth stress. The principal remaining task is that of increasing the productivity of these man-made reservoirs through engineered solutions.