Tasmanian progress to date
Exploration and development strategy
KUTh Energy's exploration strategy for the Tasmanian project is to undertake a comprehensive exploration program that combines a range of modern field geology and geophysical techniques. Heat flow measurements will be taken across the tenements using a 20km x 20km grid of shallow (~300m deep) drill holes. The eastern Tasmanian granitic suite will be followed at depth using geophysical survey methods such as gravity surveys, magneto-telluric surveys, aeromagnetic surveys and seismic surveys. All results of these will then be used to more accurately target the most promising initial production zone and to develop a detailed 3D model of the thermal reservoir.
The existence of a modelled potentially economic thermal reservoir will enable the drilling of a deep (>4km) hole to test and refine the model, with positive confirmation at this stage leading to drilling a production well and subsequent injection well in preparation for proof of concept circulation and commercial upscale.
As outlined above, KUTh Energy is employing a range of geological and geophysical tools to most accurately understand the deep geology of the project area, and define and access the potential hot rock geothermal resource. Below is an overview of our progress in each area, however for more detailed information of ongoing progress, please refer to our Investor Centre.
Heat flow mapping
Location map showing reported heat flow (HF) values determined from KUTh Energy’s shallow drilling program
Following the first stage of detailed historic data review as outlined above, KUTh Energy commenced its heatflow program in September 2007. This program has involved the drilling of 36 boreholes (approximately 300m deep) across both tenements, in a 20km x 20km grid, to provide a comprehensive regional heatflow map across KUTh Energy's entire project area. This comprehensive approach takes longer than using existing boreholes or temperatures, but provides a superior outcome both in terms of data integrity and coverage. This work is key to developing a sound regional heatflow map which can be used to target the most promising initial production drilling location and to provide a guide for the long term production capacity and development strategy in Tasmania.
Following drilling, each hole has been thermally equilibrated for a period of 2-3 months (to ensure temperature readings are not affected by drilling activity), before downhole temperature logging and core sampling. The results from each hole have then been analysed to produce an estimate of heat flow at that location. Each heat flow value is then added to KUTh Energy's heat flow map to provide an overall picture of the tenement and to identify the 'hottest' parts of the project area for targeting.
All shallow drilling has now been completed, with temperature measurement and heat flow estimates completed for nearly all holes. The completed suite of heat flow estimates is a crucial geothermal resource targeting tool and will form a key input into KUTh Energy's 3D resource model.
Please view our latest heat flow release, which provides an overview of our shallow heatflow results to date.
Tamar Conductivity Zone (TCZ), defined, by recent MT survey, superimposed on a shallow heat flow image. The southern extension of the TCZ is heading towards KUTh Energy’s tentative deep drilling target zone
Magneto-Telluric survey
Magneto-Tellurics (MT) is a geophysical survey method which takes advantage of disturbances in the Earth’s natural electro-magnetic field to detect variations in the electrical conductivity of rocks at depth. The results produced by this technique provide two-dimensional models or ‘profiles’ of variations in the electrical conductivity of the earth beneath the survey lines. By application of knowledge of both local and general rock properties these images can be interpreted and related to the coinciding geology.
In late 2008 KUTh Energy undertook a large MT survey consisting of two East-West survey lines across the main project tenement, consisting of 96 data collection stations at 1km intervals. Independent models derived from the MT survey data indicate the presence of large electrically conductive bodies in the vicinity of both survey lines, confirming the presence of the Tamar Conductivity Zone (TCZ) extending South toward KUTh Energy's preliminary geothermal target area. The TCZ is a recognised feature characterised by anomalous electrical conductivity, and due to its very nature is likely to be a brine filled fracture system. The intersection of the TCZ with KUTh Energy's high heat flow area represents promising potential, as it may reduce the requirement for fracturing activities to create a commercial enhanced geothermal system.
Please view our latest MT survey results release, which provides an overview of our MT results to date.
Following on from the success of this work, KUTh Energy has now commissioned a further large MT survey to, in part, confirm the possible continuation of the TCZ into our geothermal target zone. The survey lines for this latest survey are focused within the central Midlands are in the middle of KUTh Energy's main tenement, and will provide a more detailed understanding of the TCZ in this area of interest. Results from this survey will be released in the second half of 2009.
Aeromagnetic survey
KUTh Energy is using both existing Mineral Resources Tasmania (MRT) and other independent aeromagentic survey data in combination with other geophysical methods to build a detailed understanding of our project area geology. Aeromagnetic surveys records the magnetic properties of rocks, used to differentiate between igenous and some sedimentary rocks, also to determine basement rock depth. Such information is vital to understanding the thermal insulating properties of rock cover in an area and the depth of thermally anomalous granites, which assists with planning and targeting for deep drilling and production.
Updates will be provided on our progress via our Investor Centre.
Expansion of project area
It is clear from our heat flow results to date that the area of high heat flow extends to the west beyond our existing tenement boundary (SEL 26/2005). We have consequently applied for and been granted a new geothermal exploration licence over an area of about 4,000 km2 immediately adjacent to the western boundary of our current tenement in order to capture what could be an extension of the high heat-flow anomalous area.
Defining the Hot Rock Target Zone
Predicted surface Heat Flow contours (labelled in mWm-2) overlain across predicted depth to top granite from gravity data. Coincidence of high heat flow (>100mWm-2) and relatively shallow granite (3-4km) allow identification of an initial Hot Rock Target Zone. [Colours represent depth to top of granite, with mid-spectrum colours in the ideal depth range].
KUTh Energy's data collection and analysis activities are providing a consistent understanding of the project area. They provide a clear indication of the existence of a substantial hot-rock geothermal anomaly in central eastern Tasmania.
The anomaly comprises an area of about 4,170 km2 in which there is high crustal heat flow above 90 mWm-2. It includes an area of about 620km2 with very high heat flow above 100 mWm-2. Our exploration plans are now focusing on a 50km2 area in which the zone of very high heat flow coincides with granite buried 3-4 km deep, as inferred from gravity mapping.
This smaller area, our Hot Rock Target Zone, is likely to be further refined to identify a location for future deep drilling. A range of geophysical methods will be employed in this task over the next quarter, including a new 3D Magneto-Telluric survey and a new aeromagnetic survey (as noted above). These results will be combined with existing data to form the basis for a 3D thermal resource model in this area.
To read more about our activities leading to the defining of KUTh Energy's initial Hot Rock Zone, please view our latest Quarterly Report.
UPDATE
KUTh Energy has recently released details of Tasmania's first inferred geothermal resource
ASX release
Inferred Resource Statement
Inferred Resource Report
Forward planning
Concurrent with the exploration and analysis activities above, we are actively planning for the next stages of exploration and project development. Key amongst our priorities are the development of our 3D resource model, coordination of activities for deep drilling and proof of concept, and planning for the establishment of power generation, network connection, transmission and commercial operation.
This page is regularly updated with our progress, however for the latest information, please visit our Investor Centre or subscribe to our Email Updates.