Geoscience Australia's $58.9M 5-year Onshore Energy Security Program began in 2006 and includes a new Geothermal Energy Project. The Project aims to assist in the development of a geothermal industry in Australia by: providing precompetitive geoscience information, including acquisition of new data; informing the public and government about Australia's geothermal potential; and partnering with industry in international promotional events for the purpose of attracting investment. This abstract gives a brief summation of activities undertaken by Geoscience Australia within the Onshore Energy Security Program, principally those of the Geothermal Energy Project.

Extended abstracts from various authors compiled as the Proceedings volume of the 2012 Australian Geothermal Energy Conference, 14-16 November 2012, Crown Plaza, Coogee Beach, Sydney.

Preliminary compilation of data in the onshore Carptentaria Basin, Northern Territory. This basin, previously named the Dunmarra Basin, is poorly understood. This Record details the compilation of data in 3D for the basin. Data included are surface geological mapping, drillholes, gravity, magnetic, radiometric, visible LANDSAT, seismic reflection and digital elevation data.

Geoscience Australia's $58.9M 5-year Onshore Energy Security Program began in 2006 and included a new Geothermal Energy Project. The OESP concluded in June 2011 but the Geothermal Energy Section continues albeit with reduced funding. The project aims to assist the development of a geothermal industry in Australia by: providing precompetitive geoscience information, including acquisition of new data; informing the public and government about Australia's geothermal potential; providing technical advice to government; and partnering with industry in international promotional events for the purpose of attracting investment. This abstract gives a brief summation of activities undertaken by Geoscience Australia within the Onshore Energy Security Program potentially of interest to geothermal explorers.

Valuable new insights into the distribution and geological settings of U, Th and K rich (HHP) granites in Australia have come from interrogation of national datasets, supplemented by wide-ranging regional studies and inversion modelling conducted under a major Government energy security initiative. The increasing attention being paid to these granites in Australia reflects their importance in relation to geothermal energy and uranium mineralisation, which will be outlined. The oldest HHP granites in Australia are potassic, siliceous I-type late Archean (2.85 and 2.65-2.63 Ga) granites in the Pilbara and Yilgarn Cratons, Western Australia. These were produced by melting of Archean TTG-rich crust. The HHP granites were produced on a massive craton-wide scale in a geodynamic environment that is poorly understood, although high geothermal gradients appear necessary. This magmatism effectively redistributed U and Th into the middle and upper crust and stabilized the Pilbara and Yilgarn Cratons. The Proterozoic in Australia, particularly in the age range 1.8-1.5 Ga, is typified by granites with high K and, locally, very high U and Th abundances. In general, these HHP granites were also emplaced late in the evolution of the Proterozoic crust and are considered to be the result of crustal reworking, under high geothermal gradients. It is probable that there was associated crustal thinning, and mantle contributions of heat and some material. I- and S-type HHP granites also occur within the Australian Paleozoic. Their chemical compositions, including the elevated U and Th contents in the majority of these rocks, reflect extensive and efficient fractional crystallisation processes in magmas derived predominantly by crustal melting. Geodynamic environments are considered to range from late syn-tectonic, to post-collisional and back-arc extension.

This animation illustrates the various stages of development of Hot Rock geothermal resources for electricity generation. The animations were produced in GAV by the 3D animator, using 3D Studio Max software. Professional voice-over has been added, as well as sound effects. This version is based on the original version - 08-3385, geocat no.68461.

Work conducted at the Bureau of Mineral Resources (now Geoscience Australia) in the early 1990s was instrumental in bringing hot rocks geothermal research and development to Australia. Following the announcement of the Australian Government's Energy Initiative in August 2006, a new geothermal project has been started at Geoscience Australia. This paper, presented at 3rd Hot Rock Energy Conference in Adelaide, August 2007, outlines the scope of the Onshore Energy Security Program and the development, implementation and progress to date of the Geothermal Energy Project.

The Geoscience Australia (GA) building located in Symonston, ACT utilises one of the largest GSHP systems in the southern hemisphere. It is based on a series of 210 geothermal heat pumps throughout the general office area of the building, which carry water through loops of pipe buried in 352 bore holes each 100 metres deep and 20cm in diameter. The system is one of the largest and longest operating of its type in Australia, providing an opportunity to examine the long term performance of a GSHP system. A 10-year building review conducted in 2007 estimated that the system had saved about $400,000 in electricity costs. When comparing energy performance in the annual 'Energy Use in the Australian Government Operations' reports, the GA building has maintained energy performance and targets that might normally be expected of a general office administration building. This is significant given the requirements to provide additional fresh air to laboratories and 24/7 temperature control to special storage areas. The energy savings can be attributed to the GSHP system and other energy efficient design principles used in the building.

In Australia to date, there are only a handful of projects that have drilled deep wells to intersect geothermal reservoir targets, and limited flow tests have been performed. Consequently, the characteristics and behaviour of geothermal reservoirs in Australia (geometries, fluid chemistry, mineralogy, permeability type and distribution, temperature distribution etc.) are not well understood. It is clear that the geological variability in the geothermal plays targeted to date (and in the future) will result in diverse reservoir types, but regardless of setting, all geothermal reservoirs must have sufficient permeability to enable fluid flow and heat extraction. Geochemical tracers have been used internationally for many years to improve the understanding of reservoir dynamics in conventional geothermal systems. Their application in Australia is yet to be widely demonstrated however they provide an attractive opportunity to learn more about geothermal reservoirs in Australian geological settings. Tracers can be classified as either conservative or reactive, and can be used in liquid-phase, vapour-phase or two-phase reservoirs. Tracer tests can provide information on inter-well connectivity, fluid mean residence time, recharge areas, swept pore volumes, temperatures, fracture surface area, flow-storage capacity relationships and volumetric fluid sweep efficiencies. In addition, tracer data can be used with numerical transport codes to help validate 3D reservoir models. This paper presents an overview of existing tracers and their capabilities, and new research directions in tracer science internationally.

The Habanero Engineered Geothermal System (EGS) in central Australia has been under development since 2002, with several deep (more than 4000 m) wells drilled into the high-heat-producing granites of the Big Lake Suite to date. Multiple hydraulic stimulations have been performed to improve the existing fracture permeability in the granite. The stimulation of the newly-drilled Habanero-4 well (H-4) was completed in late 2012, and micro-seismic data indicated an increase in total stimulated reservoir area to approximately 4 km². Two well doublets have been tested, initially between Habanero-1 (H-1) and Habanero-3 (H-3), and more recently, between H-1 and H-4. Both doublets effectively operated as closed systems and excluding short-term flow tests, all production fluids were re-injected into the reservoir at depth. Two inter-well tracer tests have been conducted since 2008, to evaluate the fluid residence time in the reservoir alongside other hydraulic properties, and to provide comparative information to assess the effectiveness of the hydraulic stimulations. The closed-system and discrete nature of this engineered geothermal reservoir provides a unique opportunity to explore the relationships between the micro-seismic, rock property, production and tracer data. The most recent inter-well tracer test occurred in June 2013, which involved injecting 100 kg of 2,6 naphthalene-disulfonate (NDS) into H-1 to evaluate the hydraulic characteristics of the newly-created H-1/H-4 doublet. Sampling of the production fluids from H-4 occurred throughout the duration of the 3-month closed-circulation test. After correcting for flow hiatuses (i.e. interruptions in injection and production) and non-steady-state flow conditions, tracer breakthrough in H-4 was observed after 6 days (compared to ~4 days for the previous H-1/H-3 doublet), with peak breakthrough occurring after 17 days. Applying moment analysis to the data indicated that approximately 56% of the tracer was returned during the circulation test (vs. approximately 70% from the 2008 H-1/H-3 tracer test). This suggests that a considerable proportion of the tracer may lie trapped in the opposite end of the reservoir from H-4 and/or may have been lost to the far field. Flow capacity:storage capacity plots derived from the H-1/H-4 tracer test indicate that the Habanero reservoir is moderately heterogeneous, with approximately half of the flow travelling via around 25% of the pore volume. The calculated inter-well swept pore volume was approximately 31,000 m³, which is larger than that calculated for the H-1/H-3 doublet (~20,000 m³). This is consistent with the inferred increase in reservoir volume following hydraulic stimulation of H-4.