Publication Date:
2019
Description:
〈p〉We show that near–real-time seismic monitoring of fluid injection allowed control of induced earthquakes during the stimulation of a 6.1-km-deep geothermal well near Helsinki, Finland. A total of 18,160 m〈sup〉3〈/sup〉 of fresh water was pumped into crystalline rocks over 49 days in June to July 2018. Seismic monitoring was performed with a 24-station borehole seismometer network. Using near–real-time information on induced-earthquake rates, locations, magnitudes, and evolution of seismic and hydraulic energy, pumping was either stopped or varied—in the latter case, between well-head pressures of 60 and 90 MPa and flow rates of 400 and 800 liters/min. This procedure avoided the nucleation of a project-stopping magnitude 〈i〉M〈/i〉〈sub〉W〈/sub〉 2.0 induced earthquake, a limit set by local authorities. Our results suggest a possible physics-based approach to controlling stimulation-induced seismicity in geothermal projects.〈/p〉
Electronic ISSN:
2375-2548
Topics:
Natural Sciences in General
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