Demonstration of Soft Stimulation Treatments in Geothermal Reservoirs

Abstract

Enhanced geothermal systems (EGS) allow for widespread use of enormous untapped geothermal energy potential. EGS measures are generally intended to improve productivity (or injectivity) of a geothermal reservoir by increasing the overall transmissivity of the reservoir rocks. Soft stimulation approaches are under development and applied to enhance the reservoir performance with treatments that negate potential hazards such as induced seismicity or environmental contamination. Scientific progress was made on topics such as fluid-rock interaction, the improved determination of the stress field and on the analysis of induced seismicity. Experiences with hydraulic treatments including mitigation of triggered or induced seismic events will be reported. These various methods are dependent on the geological system, comprising the rocks, the rock structures, the tectonic situation and the stress field. Hydraulic treatments sometimes induce seismic events that can, in some cases, be felt at the surface and jeopardize public acceptance of a project. Hydraulic, thermal, and chemical treatments are options to address EGS requirements for different geological settings and different geothermal exploitation strategies. These issues are addressed by the DESTRESS project (DESTRESS= Demonstration of soft stimulation treatments in geothermal reservoirs).