Use of Tracers to Interrogate Fracture Surface Area in Single-Well Tracer Tests in EGS Systems

Abstract

Based on the thermal decay and sorption behavior of Safranin T observed in laboratory tests and in an interwell field tracer test (Leecaster et al. and Rose et al., these proceedings), we use numerical models to demonstrate how this tracer could be employed to interrogate fracture surface area in a single-well tracer test in an Engineered Geothermal System (EGS) reservoir. We also show how lithium ion, which adsorbs to fracture surfaces but does not thermally decay (Dean et al., these proceedings), could be used in single-well tracer tests to accomplish the same objective. The interrogation of surface area in single-well tracer tests could be a very useful tool in the development of EGS reservoirs, as the effectiveness of a fracture stimulation could be evaluated before additional wells are drilled.