torrens energy

parachilna

TORRENS ENERGY HAS BUILT ON OUTSTANDING RESULTS RETURNED IN 2008 & 2009 TO ADVANCE THE PARACHILNA GEOTHERMAL PLAY TO ITS STATUS AS AUSTRALIA'S LARGEST CODE-COMPLIANT INFERRED GEOTHERMAL RESOURCE.

Above: The Parachilna Geothermal Play located on the Northern Transmission Network 230km north of Port Augusta, SA
  

In February 2010 Torrens Energy announced the completion of an additional intermediary validation drillhole where:

  • An outstanding final heat flow of 115mW/m2 was independently verified for Melkor 1, at a depth of 1,007m.
  • Modeled temperatures of ~240ºC at 4,500m were validated, representing the highest target temperature on the electricity grid in Australia.

Values are comparable to the best results from geothermal exploration in the traditionally explored Cooper Basin in far northeast South Australia, but with the clear commercial advantage of being located on the electricity grid.

In October 2009 the Parachilna Confirmation Well Notice was presented to AGL. This identified a reservoir target at 4,500m depth.  Independent validation of the Melkor 1 result and a refined drill-site location has recently been provided to AGL for their assessment under the terms of the Geothermal Alliance Agreement.

Background 

Seismic Survey Completed

Seismic surveys are necessary to define the three-dimensional geological framework for the heat interpolations by the 3D-TFM methodology.

A seismic line at Parachilna traverses 40 km of pastoral land across the Torrens Hinge Zone from the Flinders Ranges in the east to Lake Torrens in the west, over the area of heat-flow drilling. The seismic line passes just west of the town of Parachilna. The seismic line passes under the 132kV Port Augusta-Leigh Creek Power Line, which is the north-eastern boundary of the South Australian Far North Transmission Network.

Seismic information was collected down to 5,000m using the Terrex Bird-wagen MARK IV off-road carrier with HEMI 60 vibrator.

The survey showed that the western part of the profile is flat-lying insulating sedimentary sequence, underlain by heat-producing basement rocks at 3,000-4,500m. These are modeled at more than 200ºC and are ideal for the creation of a geothermal heat exchanger.

The seismic interpretation was incorporated into the 3D-TFM. The derived geological model and refined temperature distribution was then used to determine the best position of the first intermediary drill hole, Treebeard 1A.

Intermediary 'Validation Drill - Treebeard 1A

Above: Core sample from exploration well Treebeard 1A, Parachilna Project.

Treebeard 1A was completed to target depth, recording 98.4°C at 1,807m. The result was used to validate the seismic model and estimate a temperature in the interpreted basement between 3,000-4,500m.

Using the precise heat flow and geological information from Treebeard 1A, the 3D-TFM modeling identified the optimum point to locate the deep geothermal well planned for 2010.

The more recent heat-flow measurements at Parachilna are very high by geothermal standards, peaking at 120mW/m2.

These results enhance the prospectivity of the Parachilna Geothermal Play, bringing the Company a step closer to deep drill testing of this outstanding target.

Nilpena Seismic Survey

Some 20km north, a second seismic profile was completed in February 2010.  This Nilpena survey confirmed the geological framework of thick flat-lying insulating sedimentary sequence overlying heat-producing basement at ideal depths. This information de-risks the highly prospective geothermal target 'book-ended' to the south by the Parachilna line.