Current Research

Focus topics

The principal focus topics of Australian research relate to:

  • high grading of locations with high potential for the development of Enhanced Geothermal Systems
  • assessment of technologies (including numerical simulation techniques) with high potential to minimise costs and maximise efficiencies in the development of Enhanced Geothermal Systems
  • environmental impacts of developing Enhanced Geothermal Systems, including potential induced seismicity that can be associated with the fracture stimulation of geothermal reservoirs.

These research directions are aligned with Geothermal Implementing Agreement (external site) (GIA) Annexes I and III.

 

Government Funded Research

Geoscience Australia
Geoscience Australia conducted considerable stakeholder consultation to develop a plan to enhance understanding of Australia’s geothermal energy resources under the auspices of the Federal Government’s five year (2006–2011) Onshore Energy Security Program. Key activities will include:

  • the consolidation of existing geothermal data
  • the acquisition of additional, infill (precompetitive) geothermal and cognate data (including new thermal conductivity and heat flow measurements)
  • assessments leading to a new detailed hot fractured rock model (map) with refined gridding techniques
  • constructing an information system for the dissemination of geothermal and associated data.

Australian National University – Australian Capital Territory
Research has focused on development of a new database of temperature measurements made in 5722 wells across Australia that has been used to construct improved maps of the spatial distribution of temperature in the Australian crust.  This work was undertaken by Dr Prame Chopra and Fiona Holgate. The new database, Austherm04, builds upon the earlier work of Somerville et. al. (1994) by greatly improving data quality control and by including temperature data from a further 1430 wells. Whilst there has been some enhancement of the overall spatial coverage, the bulk of the new data are still largely clustered within the same provinces that dominate the dataset published by Somerville et al. (1994). As a result, data distribution across the continent still tends to be rather patchy and irregular with some regions well represented and others not (see the map under Status of Geothermal Licence Activity). Furthermore, these data are yet to be integrated with a predictive models that may define potential ‘sweet-spots’ and accordingly do not yet represent all prospective trends. An Arc/Info GIS coverage has been built from the Austherm04 database (Chopra and Holgate, 2005).

The crustal temperature maps produced in this study reveal large spatial variations in temperature across continental Australia. Lowest temperatures occur where basement is exposed at the surface such as in the Yilgarn Block, Gawler Craton and Lachlan Fold Belt. High temperatures are associated with thick sedimentary basin cover and the inferred presence of high heat production granites under the sedimentary sequences. Particular examples include the Cooper-Eromanga, Macarthur and Canning Basin regions.

Other smaller areas of relatively elevated crustal temperature that may represent future HDR targets include parts of the Sydney, Perth and Murray Basins. Whilst representing significant improvements over the previous Somerville et al. (1994) map, the new crustal temperature maps continue to be influenced by artifacts caused by the strongly heterogeneous spatial distribution of the subsurface temperature data across continental Australia. More sophisticated geostatistical methods and analysis on a province by province basis may offer some improvements but further temperature exploration data will probably be required to significantly improve the resource analysis.

This geothermal work at the ANU has now been completed with the departures from the university of Drs Chopra and Holgate to Earthinsite Pty Ltd and Geoscience Australia respectively. 

References

Chopra, PN and Holgate, F 2005. A GIS analysis of temperature in the Australian Crust, Proceedings of the World Geothermal Congress, 2005, Antalya, Turkey, 24–29 April, 2005.

Somerville, M, Wyborn, D, Chopra, PN, Rahmann, SS, Estrella, D and van der Muellen, T, 1994. "Hot Dry Rocks Feasibility Study", Australian Energy Research and Development Corporation Report 94/243, pp 133.The 2nd Hot Rock Energy Conference, 16–17th February 2006, Adelaide. To order conference proceedings contact The Australian Journal of Mining.

University of New South Wales
The School of Petroleum Engineering at the University of New South Wales (UNSW) has made a strong commitment to the development of renewable energy and has been actively participating in developing technology for the exploitation of geothermal energy in Australia since the first HDR Conference held in Canberra in 1992. Together with Geoscience Australia, it actively participated in collecting geophysical and temperature data from different parts of Australia and prepared a heat map of Australia in 1994.

Following this it carried out a major study to characterise temperature, stress and natural fracture systems of the basement in the Cooper Basin. As part of this study the School also developed an innovative fracturing technology for the development of geothermal reservoir. This study was primarily funded by ERDC and industry. To commercialise the technology it formed a geothermal company, Scopenergy Ltd, in January 2001 (currently owned by Eureka Capital Partners) to hold the major geothermal licences in Mount Gambier region of South Australia. The UNSW School of Petroleum Engineering has worked with Scopenergy on a number of issues, including:

  • characterisation of geothermal reservoirs in particular in sedimentary rocks
  • geothermal reservoir development by hydraulic fracturing
  • fluid flow and production estimation in fractured sedimentary reservoirs.

The program is being funded by the UNSW, Australian Greenhouse Office (AGO) and industry.

In 2005, the School developed a numerical simulation technique for characterisation of fracture systems in geothermal reservoirs adopting a geostatistical approach that incorporates field data. Initial results are very encouraging and the School is currently working to advance this work. The School has also developed a numerical geothermal reservoir simulator to estimate hot water recovery. An important feature of this model is that it simulates fracture system with spatial distribution and considers fluid flow between fracture and matrix.

Australian School of Petroleum, Adelaide University – South Australia
The South Australian Department of Primary Industries and Resources (PIRSA) allocated AUS $50,000 in June 2005 to the Australian School of Petroleum at University of Adelaide to undertake a research study of potential induced seismicity associated with the fracture stimulation of Enhanced Geothermal Systems (EGS) wells in the Cooper Basin and then undertake similar studies in other prospective EGS provinces. The Cooper Basin study, led by Dr Suzanne Hunt, used predictive modelling of local stress change to forecast probable impacts from the fracture stimulation of naturally fractured granites in the vicinity of the Habanero wells drilled by Geodynamics. This study (Hunt and Morelli, 2006) is fully aligned with the aims of the GIA for its members to pursue collaborative efforts that address issues of “significant concern to the acceptance of geothermal energy in general but Enhanced Geothermal Systems (EGS) in particular. The issue is the occurrence of significant seismic events in conjunction with EGS reservoir development or subsequent heat extraction”.

Outputs from the project included numerical models that assess potential impacts (on the local in-situ stress field) from the development of EGS reservoirs and also the development of finite difference models to assess the likelihood of damage to petroleum wellbores and completions that might possibly be caused by a seismic wave hitting a wellbore at various depths. The one year study, Cooper Basin HDR hazard evaluation: Predictive modeling of local stress changes due to HFR geothermal energy operations in South Australia was completed in June 2006. The report has been peer review and reviewer comments are also provided.

Key conclusions from Hunt and Morelli (2006) are:

  • The Cooper Basin in South Australia is ideally suited to EGS activities in terms of natural background seismicity levels
  • Reactivation of any basement faults in the region is unlikely in the vicinity of the Habanero Site
  • Induced seismic events at the Habanero well site in the Cooper Basin fall below the background coefficient of ground acceleration (0.5 g) thereby not exceeding the government’s current building design standards for peak ground acceleration
  • The static stress damage zone would not be expected to have any impact on identified local structural features. This is due to the nearby faults being beyond the reach of the induced seismicity associated with EGS activity.

Below is a map of basement in the Cooper Basin showing well locations. The inset bullet shows the attenuation radiation distance from Geodynamics' Habanero 1 well site. (After Hunt and Morelli, 2006.)

Map of basement in the Cooper Basin showing well locations. After Hunt et al., 2006.

The results and conclusions from this study were presented by Michael Malavazos, Chief Petroleum Engineer, PIRSA at the GRC Conference in San Diego in September 2006.

Reference

Hunt S P and Morelli C, 2006. Cooper Basin HDR hazard evaluation: Predictive modelling of local stress changes due to HFR geothermal energy operations in South Australia. Prepared by the University of Adelaide for South Australian Department of Primary Industries and Resources. University of Adelaide Report Book 2006/16.

Monash University –Victoria
Geothermal research has focussed on measuring and mapping heat flow and temperature distribution in the crust across SE Australia during 2005.

Northern Territory
On the basis of geology, existing physiography and hot rock potential, an area in the vicinity of Katherine and within the zone covered by the existing major NT power transmission grid looks quite exciting.  Hot Springs in the Daly region 100km north west of Katherine and at Mataranka 120km SE of Katherine coincide with an interpreted presence of a major crustal heat source in the region.

NT government geologists have had little opportunity to further develop the interpretation of the heat source geology but the NT has good regional magnetic, gravity and particularly radiometric coverage which could be utilised by explorers to focus their research.

To assist in identifying geothermal opportunities in the Territory a review of the geothermal potential of the Territory is being prepared by one of Australia’s leading geothermal experts, Dr Graeme Beardsmore.  The result of this study will be presented at the Annual Geoscience Exploration Seminar (AGES) at Alice Springs in March 2007. It will also be released as a CD containing a summary report and GIS. The GIS is intended to be a toolkit for use by geothermal explorers, containing multiple layers of information relevant to the assessment of geothermal potential.