THREE DIMENSIONAL INTERPRETATIONS OF SINGLE-WELL ELECTROMAGNETIC DATA FOR GEOTHERMAL APPLICATIONS

摘要

An efficient 3-D electromagnetic (EM) inversion algorithm has been developed for geothermal applications and tested successfully using a set of single-hole EM logging data. The data was collected at an oil field undergoing CO_2 injection in southern California using a single-hole EM tool, Geo-BILT, developed by Electromagnetic Instruments, Inc (EMI). The tool is equipped with a multi-component source, and multi-component receivers at different separations. The inversion result provides a reasonable electrical conductivity image to a distance of 10 m from the well, and illustrates several zones with lateral conductivity variations that could not be resolved with traditional induction logging tools. The successful case study demonstrates potential applications of the tool and software for characterizing fracture systems in geothermal reservoirs.