Seismic Methods for Geothermal Reservoir Characterization and Monitoring Using Fiber Optic Distributed Acoustic and Temperature Sensor

Abstract

Summary Enhanced Geothermal Systems (EGS) offer unique monitoring and characterization challenges. The harsh, high temperature downhole environment and heterogeneous nature of discrete hydraulic features usually governed by discontinuous fractures and faults requires robust measurement technology with advanced resolution capability. Borehole DAS installations are often associated with VSP surveys. However, tomographic seismic, earthquake seismology, and microseismic applications have also been demonstrated at a geothermal field. The spatio-temporal resolution achieved with DTS allows for characterisation of hydrothermal processes as well as estimation of thermal diffusivity with depth. Here we present the use of fibre optic distributed temperature and acoustic systems at both hydrothermal and EGS sites as part of the subsurface geothermal characterisation.