| Abstract |
IEA-Geothermal has undertaken joint research and information sharing between member countries regarding the mechanisms and adaptive management options to address the adverse and beneficial effects of geothermal induced seismicity. Current research is associated with deep drilling into both moderate and high temperature geothermal systems. Superhot resources are hosted in volcanic and tectonically active settings where brittle-ductile transition conditions can be expected within the shallow crust. This paper discusses aspects of this work, in relation to monitoring results from several projects, seeking to share knowledge acquired and inform future enquiry. The work of the Geothermal Technology Collaboration Program, Working Group 13 (Emerging Geothermal Technologies), Task D (Induced Seismicity) is described in this paper. The objective is to help reduce induced seismicity risks and barriers, both real and perceived, while advancing the demonstrated benefits of improved monitoring and passive seismic processing tools, and thereby enhance deployment of geothermal energy technology, globally. Induced seismicity risk remains an issue for geothermal projects. Through collaborative modelling and data sharing, the key mechanisms behind induced seismicity that can accompany long term injection are investigated. In high temperature operating geothermal systems, typically hosted in fractured reservoirs, monitoring of micro-seismicity combined with seismic tomography (velocity inversion) provides geothermal reservoir modelers and resource managers with improved information on geothermal reservoir behavior and extent. This information enables production and reinjection strategies to be fine-tuned to improve utilization sustainability. The knowledge gained can also help develop better strategies for risk reduction, resource expansion and for choosing targets for make-up drilling. |