Injection Induced Seismicity and Geothermal Energy

Abstract

Over the past few years injection-induced seismicity (IIS) has become an increasingly important issue that Earth scientists working in the geothermal, mining, petroleum and other industries must address. We present a brief review of the history of IIS, the importance of IIS to the growth of the geothermal energy industry, and suggest possible paths forward to managing the risks associated with IIS. IIS occurs when the fluid pressure in a fault or fracture reaches a critical value above which the friction preventing fault slip is overcome. This concept was proposed in 1959, inadvertently demonstrated at the Rocky Mountain Arsenal in 1962, further tested at Rangely Oil field in 1969, and has been incorporated into continuous injection operations at Paradox Valley since 1996. EGS reservoir creation relies upon controlled IIS to create the high surface-area fracture paths necessary for sustainable and economic heat extraction. The lessons learned from past EGS projects, in particular at two projects along the Rhine Graben in Europe, are being used to refine the plans for future projects.