| Abstract |
The Paralana Engineered Geothermal Project is located 600km north of the city of Adelaide in South Australia (Figure 1). The project is testing for viable geothermal resources, within a sedimentary basin that lies immediately east of known high heat producing Mesoproterozoic basement rocks of the Mt Painter Region. In this area, 2D reflection seismic survey data and potential field geophysical (aeromagnetic, magneto-telluric and gravity) data delineate a major half graben informally termed the Poontana basin. Based on the interpreted geophysical data, Petratherm postulates that the high heat producing basement rocks observed in outcrop, continue under the insulating cover material, with the maximum thickness of the sedimentary cover in sections of the Poontana Sub-basin being modeled at greater than five kilometres. This favourable arrangement of thick sediments overlying anomalously radiogenic basement suggests that the Paralana area is an ideal location to test the development of an Engineered Geothermal System. Petratherm Limited in joint venture with a major oil and gas (Beach Energy) and power industry energy utilities (TRUenergy) are initially seeking to build a 7.5 MWe commercial power development to supply a local mine. In the second half of 2009 a deep geothermal well (Paralana 2) was drilled to 4012m. The well was designed as an injector, the first of an initial two well program to prove circulation between wells. An innovative strategy for development of the EGS reservoir is planned, involving massive hydraulic stimulation of multiple target zones within the sedimentary overburden. Multiple zone stimulation increases the chance of achieving a commercial flow rate which is the key commercial barrier for EGS developments around the world. |