GEISER · Geothermal Engineering Integrating Mitigation of Induced Seismicity in Reservoirs

The project contributes to the improvement of the concept of Enhanced Geothermal Systems by investigating the role of induced seismicity, which is twofold: (i) an instrument to image fluid pathways induced by hydraulic stimulation treatments, which has been done to some extent in previous projects; and (ii) an implication of such treatments to potential seismic hazards. The mitigation of induced seismicity to an acceptable level is the major intent of this project. For this purpose, we set as our goals (1) to understand why seismicity is induced in some cases but not in others; (2) to determine the potential hazards depending on geological setting and geographical location; (3) to work out licensing and monitoring guidelines for local authorities, which should include a definition of what level of ground motion is acceptable; and (4) to develop strategies to fulfil the task of the stimulation and improve the hydraulic properties of the geothermal reservoir without producing large magnitude events. To accomplish the project goals a high quality database of case studies will be assembled. This will include data on seismicity and ground motion, geomechanics, reservoir characteristics, injection/production, and surface deformation, as well as information on the local stress field and local geology. The interpretation will be based on data from the sites: Soultz-sous-forêts (France), Basel (Switzerland), Groß Schönebeck (Germany), KTB (Germany), Larderello/Latera (Italy), Campi Flegrei (Italy), Hengill, Krafla, Reykjanes (Iceland), Groningen (Netherlands), and others (Berlin, El Salvador; The Geysers, USA). The GEISER-project will overcome shortcomings of previous work by including model based forecast of stimulation and/or production induced seismicity. Developing soft stimulation strategies and guidelines on how to react on induced seismicity will support the acceptance of geothermal applications.