Imaging of the Soultz Enhanced Geothermal Reservoir Using Microseismic Data

Abstract

Imaging the fracture zones and flow path networks of geothermal reservoirs is a difficult and costly task but is one that is essential to the successful development and operation of an Enhanced Geothermal System. Seismic data can provide information about reservoir structure within the reservoir rock mass at locations away from boreholes, where many methods can provide information. However, imaging with seismic data is often difficult due to the sparse sensor array that samples the seismic wavefield. We use microseismic events induced from production and hydrofracturing as sources for imaging the Enhanced Geothermal Reservoir at Soultz-sous-Forets, France. Data from the 1993 stimulation are used. We begin by determining a three dimensional velocity model for the reservoir using Double Difference Tomography for both P and S waves. We then analyze waveform characteristics to provide more information about the locations of fractures within the reservoir.