A Special Issue on Geothermal Energy

Abstract

It is a pleasure for us to introduce this Special Issue of Mathematical Geosciences on “Geothermal Energy”, dedicated to all members of the worldwide geothermal community. Geothermal energy is clean, indigenous, and base-load renewable energy, not subject to intermittencies of weather and time-of-day. In recent years, great advances have been achieved in reservoir modeling, geology, geophysics, geochemistry, and other areas of geosciences. These achievements have contributed to steady growth of the geothermal industry. Facing the rapid evolution of the field, the goal of this special issue is to gather some of the recent contributions about methods and theories relevant to the geosciences of finding and developing geothermal energy. The first of the six papers on this Special Issue is by Jonny Rutqvist, Patrick F. Dobson, Julio Garcia, Craig Hartline, Pierre Jeanne, Curtis M. Oldenburg, Donald W.Vasco, andMarkWalterswho dealwith the prestimulationmodeling and interpretation of the stimulation in the northwest Geysers EGS (Enhanced Geothermal System) demonstration project, California. EGS is one of the hot spots in geothermal research in recent years. EGS has a huge potential. It is clear that EGS is presently still at the “proof of concept” stage. Without question, EGS is currently a great challenge for geothermal industry. However, these authors were able predict the extent of the stimulation zone reasonably well. Their modeling data indicate that the microearthquake events are related to shear reactivation of preexisting fractures that are triggered by the combined effects of injection-induced cooling around the injection well and small changes in steam pressure. Many geothermal reservoirs, including EGS, are fractured systems. It is important to characterize the heat transfer in such fractured reservoirs. Suzuki et al. derived a