The work will be carried out at the Blanche-1 well by the CSIRO together with GEO-Meß-Systeme GmbH, a leading German contractor, in early February to determine the pressure required to fracture the hot granites.

Temperature measurements taken previously at the well, which was drilled to a depth of 1935m, has already proven the existence of the heat anomaly in the Olympic Dam region.

Green Rock said information gathered from the hydraulic fracture testing would be used to help design two deeper wells and the associated water circulation testing.

These two wells would be used to drive a 3-5MW pilot plant, in the lead-up to a much larger 400MW commercial base-load facility.

“This hydraulic fracture testing is a low cost, high reward, exercise to eliminate a further level of project risk, and will provide the company with valuable information to design the two deep wells and fracture stimulation, before the company embarks upon the major drilling exercise,” managing director Adrian Larking said.

The testing program will see water injected into sealed-off intervals in the well to induce tensile fractures in the rock, at various depths down to total depth.

According to Green Rock, fractures within the rock will open when the water pressure pumped into the sealed-off zone in the hot granites exceeds the in-situ stresses.

Green Rock claims to be the first geothermal company in Australia to measure in-situ rock stresses with a slim-hole testing system of this type, before drilling and fracture stimulation to create the underground fractured reservoir.

“This technology enables ‘stress logging’ without the need for a drill-rig and associated crew and has the added benefit of significant cost savings,” the company said.

“To monitor the hydraulic fracturing in Blanche-1, the company is also importing from Europe a special high temperature slim hole acoustic televiewer, which is the first time such a slim hole tool has been used in Australia in geothermal energy wells.”