Engineering Challenges for the Innamincka Hot Fractured Rock Geothermal Development

Abstract

Geodynamics Ltd are the first company in Australia to start drilling down to over 4000m to extract the energy from hot fractured rocks at approximately 250°C. Test drilling has been conducted near Innamincka, in central Australia and Geodynamics were startled to find that the resource was a water saturated reservoir at extreme pressure rather than the expected hot dry rock system. Parsons Brinckerhoff has been engaged by Geodynamics to design a closed loop test facility between two wells. The extreme fluid pressures of about 35MPa at the surface, have presented many challenges and the impact that this has on the pipeline design, along with problems associated with the high pressure reinjection pump are presented. The pump has had multiple failures, principally related to the seal design, and these failures are analysed along with potential solutions.