Drilled to a total depth of 491 metres into the sedimentary section below the artesian aquifer, the well has now been cased and prepared for logging.
Petratherm said temperature measurements of the mud system during drilling were encouraging and suggested the presence of a significant hot rock resource.
Temperature logging is expected to take place in 10 days, subject to contractor availability and after temperatures in the well have re-equilibrated with the adjacent rock formations.
If results are in line with the company’s business model, the well will be deepened using a diamond rig, to about 1,500 metres.
This would enable acquistion of further temperature, rock and stress measurements to gauge the presence of hot rock resources in excess of 200 degrees Celsius at a 3.5 kilometre depth.
Paralana-1B was the second well in stages 1 and 2 of the company’s hot rock exploration program. Using a higher capacity rig in Paralana-1B overcame the unstable well conditions encountered in Paralana-1A, the company said.
Paralana-1B is 130 kilometres east of Leigh Creek, where existing transmission lines are expected to be capable of taking 125MW of power from any commercial development at the Paralana Project (GELs 156, 178 and 180).
Any additional diamond drilling at Paralana-1B would be undertaken around the same time as the deepening of Yerila-1, said Petratherm.
On September 14, Petratherm announced the temperature gradient profile of its Yerila-1 well's first phase compared favourably with the recorded temperature gradient of the world-class Cooper Basin hot rock occurrence.
Phase-1 of Yerila–1 was drilled to 693.5m to evaluate the geothermal potential of the Callabonna Gravity Low, which has been interpreted to represent a possible high heat producing granite at 2.5km depth.
At that time, Petratherm said it planned to use diamond drilling to extend Yerila-1 to a total depth of about 1500m. The second drilling phase will determine the thermal properties of underlying strata and confirm the subsurface model established in the first phase.
