OZTEMP: An Updated Map and Database for Predicting Temperature at Five Kilometres Depth in Australia

摘要

The development of the Australian geothermal industry over the last decade owes much to compilations of drill hole temperature data undertaken in the early 1990s in Canberra. The portrayal of this data on maps of predicted temperature at five kilometres depth, and contained heat resource calculations from this data, have shifted the perception that because Australia does not have significant current magmatic activity there is no geothermal potential. The Australian geothermal industry arguably now leads the world in terms of development of amagmatic geothermal systems for electricity generation. Work at the Bureau of Mineral Resources - Geology and Geophysics (now Geoscience Australia) provided a brief compilation of open-file drill hole temperature data, and a map of thermal gradient (Nicholas et al. 1980). The work of Somerville et al. (1994) provided a much larger compilation, and included a significant study into the resource potential that could be accessed by Hot Dry Rock technology. Finally, Chopra and Holgate (2005 - Austherm version) further extended the dataset and produced an image of the predicted temperature at 5 km that has become very widely distributed. (Figure 1). OZTEMP is the result of work undertaken to refine the Austherm database, and to utilise new datasets within a GIS for the extrapolation of temperature to 5 km depth and the interpolation between these datapoints. The method, which is largely derivative from that of Chopra and Holgate (2005), and the areas of new work, is described briefly below.