Passive seismic monitoring of a stimulation of HDR geothermal reservoir at Cooper Basin, Australia

A team of Japanese researchers, with long experience in passive seismic monitoring in the area of development of hot dry rock (HDR) and hot wet rock (HWR) geothermal systems, carried out seismic monitoring at the Australian HDR site being developed by Geodynamics Limited in the Cooper Basin. The seismic network consisting of 4 near-surface stations and 4 downhole stations detected approximately 32,000 triggers during injection of 20,000 m3 of liquid into granitic basement over 3 weeks. The authors located the events on a semi-realtime basis and the locations were fed back to the pumping side. The locations of seismic events showed sub-horizontal extension of the reservoir to 1,800 m away from the injection well at a depth of around 4,500 m. The heterogeneous source migration suggest that the reservoir was close to a critically stressed state.