Experiences in Heat Extraction Estimates From Short-Term HDR Geothermal Circulation Tests

Abstract

From two decades of examining the results of short-term circulation tests in some six HDR reservoirs around the world, several general ideas about heat extraction fiom geothermal resources have evolved. They focus on the concept of heat mining in analogy to the mineral extraction industry and involve estimating three commercial-decision parameters that can be estimated fiom early short-term circulation tests: (1) extractable resource content (reserves); (2) optimum extraction rate (deliverability); and (3) resource lifetime (longevity). A review of existing field data fiom the several HDR circulation tests are used to evaluate these parameters. It is concluded that sufficient confidence in the assessment of a fully stimulated HDR reservoir can be obtained during a long-term production test of the resource.