Completion of Habanero Closed-Loop Circulation Test

Abstract

Geodynamics has been working towards its “Proof of Concept” Enhanced Geothermal System (EGS) since drilling its first deep well in 2003 into the basement granites beneath the central Cooper Basin, NE South Australia. By 2008 there were two successful wells 560m apart connected by a stimulated fracture system located at a depth of 4,250m where the rock temperature is 247°C. Initially open loop testing was employed involving production to a pit then re-pressurization back to reservoir pressure with oil industry “frac” pumps. In late 2008 a high pressure pipe line was completed connecting the two wells at surface, and by December 2008, after initial pump failures, a six week circulation was commenced. The circulation involved flow from Habanero 3 using the natural artesian pressure, keeping the fluid at full flowing wellhead pressure through the surface pipeline, cooling the fluid near the re-injection well Habanero 1 with an air cooled heat exchanger, and using a 41-stage centrifugal pump to re-inject the fluid back into the reservoir. The results of the circulation test and of the associated tracer testing will be presented. The success of the circulation led Geodynamics to announce completion of its “Proof of Concept” in March 2009.