Microseismic Monitoring of Hydraulic Stimulation at the Australian HDR Project in Cooper Basin

Abstract

A team of Japanese researchers, who have a considerable experience in the microseismic monitoring of hydraulic stimulation/circulation of HDR/HWR/HFR reservoirs, conducted a microseismic monitoring at the Cooper Basin HDR site, Australia in the last quarter of 2003. A network of seismic instruments with 4 near surface instruments, three downhole instruments and one deep downhole instruments was set up by Geodynamics and CRIEPI. The seismic network detected approximately 32,000 triggers during injection of 20,000 m3 of fresh water into granitic basement over 3 weeks. The authors located the events on a semi-realtime basis using automatic software for picking, and the locations were fed back to the pumping side for determination of further injection plan. 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 suggests that the fractures in the stimulated zone were close to a critically stressed state.