HDR update

World Oil, April, 2005 by Perry A. Fischer

Without repeating everything that I wrote in this column in February 2004, here's an update of the Hot Dry Rock geothermal project in Cooper basin, Australia, which is making slow-but-sure progress. Nothing has occurred that would change the mindset of any observer that the area has tens of billions of barrels of oil-equivalent energy in the form of heat stored in granite.

Geodynamics completed its first well, the Habanero-1, which, at 14,505 ft, is the deepest well ever drilled in mainland Australia. It was drilled into the hottest known non-volcanic HDR resource in the world (250[degrees]C; 482[degrees]F). There were many problems during drilling, including unexpected natural fractures, higher than expected overpressures and steam--all of which might bode well for the project, although the company still intends to inject water.

One of the main risks is establishing a good, extensive frac job that propagates in a mostly horizontal direction. That now appears to have been accomplished. A microseismic monitoring network was used, monitoring from various new and existing wells, and gave a good map of the fracture network, which was presented at last fall's SEG meeting in Denver (see top figure).

Drilling the Habanero-2 was recently successfully completed, with the well reaching 14,297-ft TD. Hydraulic connection between the two wells, spaced 1,640 ft apart, has been confirmed. Drilling problems continue, although it was good to see "first steam" produced, even though it was produced during a fish recovery operation. As this goes to press, a very stubborn bridge plug is about to be removed by a coiled tubing drilling unit, after lowering overpressures at the wellhead from 5,200 psi down to 3,700 psi by injecting brine. The Reservoir Testing Program will proceed subject to the plug retrieval/drill-out.

A decision was made to speed up development of the demonstration power-generation plant. Geodynamics Power Systems (GPS) is also preparing detailed bids for generation plants totalling 85MW. Despite the drilling problems, the goal remains: to generate large-scale, zero-emission power, at costs similar to fossil-fuel power generation, using a closed-loop Kalina Cycle process, as is now in use in Iceland. Geodynamics has support from Metasource, Woodside Petroleum Ltd and Origin Energy Ltd.

fisherp@worldoil.com