Physical performance indicators for HDR/EGS projects

Three physical parameters are reviewed for HDR/EGS projects: recovery factor, reservoir impedance, and tracer-swept volume as a fraction of the rock volume delineated by acoustic emissions (AE). The first and third parameters are indicators of how extensively the reservoir is reached by the injected fluid, and the second one is a mechanical requirement for effective operation. (C) 2015 Elsevier Ltd. All rights reserved.