This presentation was delivered at the 30th NZ Geothermal Workshop in Taupo, New Zealand (10 - 13th November 2008). It summarises the key initiatives the Australian Government and State Governments have in place to support the growth of Australia's young geothermal industry.

Synthetic thermal modelling, constrained by available geological and geophysical datasets, is used to aid in geothermal target identi9fication and prioritization

Extended abstracts from various authors compiled as the Proceedings volume of the 2011 Australian Geothermal Energy Conference, 16-18 November, Sebel Albert Park, Melbourne.

A 3D map of the Cooper Basin region has been produced over an area of 300 x 450 km to a depth of 20 km (Figure 1). The 3D map was constructed from 3D inversions of gravity data using geological data to constrain the inversions. It delineates regions of low density within the basement of the Cooper/Eromanga Basins that are inferred to be granitic bodies. This interpretation is supported by a spatial correlation between the modelled bodies and known granite occurrences. The 3D map, which also delineates the 3D geometries of the Cooper and Eromanga Basins, therefore incorporates both potential heat sources and thermally insulating cover, key elements in locating a geothermal play. This study was conducted as part of Geoscience Australia's Onshore Energy Security Program, Geothermal Energy Project. This 3D data release constitutes the first version of the Cooper Basin region 3D map. A future data release (version 2 of the 3D map) will extend the area to the north and east to encompass the entire Queensland extension of the Cooper Basin. The version 2 3D map will incorporate more detailed 3D models of the Cooper and Eromanga Basins by delineating the major internal sedimentary sequences within the basins. Thermal properties will then be incorporated into the 3D map to produce a 3D thermal model. The goal is to produce a 3D thermal model of the Cooper Basin region that not only matches existing temperature and heat flow data in the region, but also predicts regions of high heat flow and elevated temperatures in regions where no heat flow or temperature data exists.

Report on energy assessment of north Queensland as part of the Onshore Energy Security Program. As part of the Onshore Energy Security Program, Geoscience Australia has undertaken a series of energy potential assessments, both on a national scale and on a regional scale in association geological framework studies. These framework studies, which are designed to provide information on geodynamic and architectural controls on energy systems, are linked to the acquisition of deep seismic, magnetotelluric and airbourne electromagnetic data. The focus of fiscal year 2008-2009 was north Queensland, stretching from the Northern Territory border to the coast, between 17° and 22° south latitude. In addition to the seismic data acquisition and interpretation, these framework studies have included geochronological studies as well as uranium mineral system and geothermal system studied in collaboration with the Uranium and Geothermal Projects. The main goal of these studies is to provide background data that can be used by industry for exploration, however the data also provide new information that can be used in assessing the potential of north Queensland for uranium and geothermal resources using geosystems (i.e. mineral and geothermal systems) methodologies in a GIS environment. This report provides such an assessment in a qualitative to semi-quantitative way. One of the goals of this analysis is to define the extent of areas or regions with known deposits; another goal was to define areas with previously unrecognised potential.

Assessments of the uranium and geothermal energy prospectivity of east-central South Australia have been undertaken using a GIS-based geological systems approach. For uranium, sandstone-hosted (including both roll-front and palaeochannel varieties), iron oxide copper-gold-uranium, unconformity-related and sediment-hosted copper-uranium mineral systems were considered. For geothermal energy, both hot rock and hot sedimentary aquifer systems were considered.

A compilation of extended abstracts as a record of proceedings of the 2nd Australian Geothermal Energy Conference, Brisbane, 11-13 November 2009

The greater Eromanga Basin is an intracratonic Mesozoic basin covering an area of approximately 2,000,000 km2 in central and eastern Australia. The greater Eromanga Basin encompasses three correlated basins: the Eromanga Basin (central and western regions), Surat Basin (eastern region) and the Carpentaria Basin (northern region). The greater Eromanga Basin hosts Australia's largest known resources of groundwater as well as major onshore hydrocarbon resources, including significant coal bed methane (CBM) that has been discovered in recent years, and also contains extensive hot-sedimentary aquifer geothermal energy systems. Additionally, the basin has potential as a greenhouse gas sequestration site and will likely play a key role in securing Australia's energy future. Finally, although no major metallic mineral deposits are currently known in the greater Eromanga Basin, there is significant potential for undiscovered uranium mineralisation. A 3D geological map has been constructed for the greater Eromanga Basin using publicly available datasets. These are principally drilling datasets (i.e. water bores; mineral and petroleum exploration wells) and the 1:1,000,000 scale Surface Geology Map of Australia. Geophysical wireline logs, hydrochemistry, radiometrics, magnetic and gravity datasets were also integrated into the 3D geological map. This study has highlighted the potential of the southwest margin of the Eromanga Basin and the Euroka arch region to contain sandstone-hosted uranium mineral systems. The report demonstrates how incorporating disparate datasets in a 3D geological map can generate an integrated mapping solution with diverse applications: 1. Provide new insights into the geology and geodynamic evolution of the basin. 2. Identify hydrocarbon resource plays. 3. Assess the basin's mineral potential (e.g., sandstone-hosted uranium mineral systems). 4. Assess the basin's geothermal potential (e.g., hot-sedimentary aquifer geothermal systems). 5. Provide resource management information (e.g., groundwater). 6. Identify potential contaminants in groundwater.

Significant volumes of Big Lake Suite granodiorite intrude basement in the Cooper Basin region of central Australia. Thick sedimentary sequences in the Cooper and overlying Eromanga Basins provide a thermal blanketing effect resulting in elevated temperatures at depth. 3D geological maps over the region have been produced from geologically constrained 3D inversions of gravity data. These density models delineate regions of low density within the basement that are interpreted to be granitic bodies. A region was extracted from the 3D geological map and used as a test-bed for modelling the temperature, heat flow and geothermal gradients. Temperatures were generated on a discretised version of the model within GeoModeller and were solved by explicit finite difference approximation using a Gauss-Seidel iterative scheme. The thermal properties that matched existing bottom hole temperatures and heat flows measurements were applied to the larger 3D map region. An enhancement of the GeoModeller software is to allow the input thermal properties to be specified as distribution functions. Multiple thermal simulations are carried out from the supplied distributions. Statistical methods are used to yield the probability estimates of the temperature and heat flow, reducing the risk of exploring for heat.

As part of the Onshore Energy and Security Program Geoscience Australia are producing regional geothermal energy assessments. The initial assessment (Huston, 2010) was conducted in the North Queensland region with a further assessment to be completed in the Gawler-Curnamona region, South Australia. The assessments, which incorporate geological, geophysical, geochemical and rock property data, identify geographic regions of high prospectivity for Hot Rock (HR) and Hot Sedimentary Aquifer (HSA) systems. The North Queensland assessment, consisting of a map of HR and HSA potential ranked from high to low was produced using GIS techniques. A heat production layer of polygons ranked from high to low was generated from solid geology maps and geochemical data. Heat production values for the lithologies were calculated using concentrations of radiogenic elements (U, K and Th). A thermal resistance ranking layer was produced by integrating thermal conductivity data with sediment thickness data. A temperature availability ranking layer was also generated based on the predicted temperature at 5 km using AUSTHERM07 database. The ranked layers were weighted based on their prospectivity potential and in conjunction with data uncertainty rankings,combined in the GIS to produce the final HR prospectivity map. To produce the HSA prospectivity map, aquifer thickness and water temperature ranking layers were added to the HR assessment.