| Abstract |
Geodynamics Limited has been developing an EnhancedGeothermal System (EGS) at Habanero in the Cooper Basin,Australia, since 2002. Prior to the hydraulic stimulation ofHabanero 4 in 2012, the system produced over 44,000seismic events, of which over 31,000 events could belocated.In November 2012, a large hydraulic stimulation was carriedout in the Habanero field. The intent of the stimulation wasto expand the existing EGS geothermal reservoir and to gaina better understanding of the geothermal system, through theseismic response caused by the stimulation. The stimulationwas conducted through Habanero 4, situated approximately680 m North East of Habanero 1, which had been used forthe original stimulations in 2003 and 2005. Over 34 ML ofwater was injected into the existing “Main Fracture” at adepth of 4,077 m total vertical depth (TVD) over a 3 weekperiod.During stimulation, seven seismic stations were used totransfer data in real time to the central processing office withan additional 17 stations recording in an offline mode andincorporated into the workflow in post-processing. In thisthree week stimulation period, over 27,000 events wererecorded, of which over 20,700 events were located. Eventmagnitudes calibrated by recordings of the permanentnetwork of Geosciences Australia were in the range of ML -1.6 and 3. Hypocenter locations indicate that seismicityoccurred on the same sub-horizontal layer structureidentified in previous stimulations. The seismic cloudgrowth is consistent with the previous 2003 stimulationperformed through the Habanero 1 well. However, itexhibits different characteristics compared to the 2005 restimulationthrough Habanero 1 where a pronounced Kaisereffect was observed near the injection well (Baisch etal.,2009).This paper aims to provide an overview of the seismicityproduced through the 2012 stimulation of Habanero 4 andhow its growth relates to previous stimulations of theHabanero field. |