Controlling fluid-induced seismicity during a 6.1-km-deep geothermal stimulation in Finland

• Published in: Science advances Vol. 5; no. 5; p. eaav7224
• Main Authors: Kwiatek, Grzegorz, Saarno, Tero, Ader, Thomas, Bluemle, Felix, Bohnhoff, Marco, Chendorain, Michael, Dresen, Georg, Heikkinen, Pekka, Kukkonen, Ilmo, Leary, Peter, Leonhardt, Maria, Malin, Peter, Martínez-Garzón, Patricia, Passmore, Kevin, Passmore, Paul, Valenzuela, Sergio, Wollin, Christopher
• Format: Journal Article
• Language: English
• Published: United States American Association for the Advancement of Science 01.05.2019
• Subjects: Earth Sciences; SciAdv r-articles
• ISSN: 2375-2548; 2375-2548
• DOI: 10.1126/sciadv.aav7224

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 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 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.