Good Practice Guideline for Managing Seismicity Induced by Deep Geothermal Operations

In this work we present a good practice guideline for managing seismicity induced by deep geothermal operations. The guideline provides a methodology for assessing induced seismicity hazard throughout the lifecycle of a geothermal project (from exploration to shutdown), for estimating to what extent induced seismicity is of concern. The idea is to iteratively assess seismic hazard, as soon as new knowledge is acquired about the reservoir and its response to geothermal operations. Hazard assessment is based on a decision tree approach, involving specific intrinsic and operational criteria, which allows to obtain hazard levels ranging from 0 (low concern) to 3 (high concern). Per each of these hazard levels, recommendations are, then, given in terms of data to be acquired, seismic monitoring and Traffic Light Systems (TLS). The approach proposed in the guideline can be applied to different types of geothermal systems (e.g. porous sedimentary aquifers, volcanic and plutonic regions, deep fractured crystalline basements, etc.), in variable geological and geothermal contexts, and under different operating conditions (e.g. EGS (Enhanced Geothermal System), non-EGS, geothermal fields, etc.). The guideline has been developed for France, but it can easily be adapted for other countries.