Flow Testing Results from Habanero EGS Project

Abstract

Geodynamics Limited has been developing an Enhanced Geothermal System (EGS) in hot granite beneath the Cooper Basin, Australia, since 2003. Four wells have been drilled at the Habanero site to depths exceeding 4,200 m and all four wells have penetrated a major fracture zone or fault which forms the reservoir. The temperature in the reservoir has been measured at 244°C at ~4,220 m below surface. In November 2012, the latest well, Habanero 4, was stimulated and production tested. The stimulation was done with water and injection rates of up to 53 kg/s were achieved. Following this stimulation, a maximum production flow rate of 38 kg/s was achieved and sustained for 84 minutes in open flow mode. From April to September 2013, Habanero 4 and Habanero 1 were operated in closed-loop mode, with Habanero 4 as the producer and Habanero 1 as the injector. Circulation was established and maintained with the aid of a surface pump, re-injecting the produced geothermal brine back into the reservoir. The heat produced was used to power a 1 MWe pilot power station. The results of these production, injection and closed-loop tests will be discussed and compared to earlier tests conducted at Habanero. Combining the results of production, injection and closed–loop tests, the likely performance of future wells at Habanero will be discussed.