| Abstract |
Accurately estimating reservoir permeability is essential for the sustainable development of geothermal resources, including enhanced geothermal systems (EGSs). Recent advances in geophysical techniques have revealed changes in electrical resistivity during EGS development. These changes may be related to spatial and temporal variations in subsurface fluid flow. However, geophysical monitoring data cannot be quantitatively interpreted due to the lack of rock physics models for geothermal reservoirs. Previous studies have shown that changes in permeability can be related to changes in the resistivity of fractured crystalline rocks. Nevertheless, the proposed permeability-resistivity relationships have not been verified using field-scale data from geothermal reservoirs. Therefore, this study aims to investigate the relationship between permeability and resistivity in geothermal reservoir rocks at multiple scales, from the laboratory to field scales. We selected several geothermal areas in Japan as test sites where previous projects obtained field-scale permeability and resistivity data and collected core samples from these sites. In the presentation, we will show the results of the permeability and resistivity measurements of cores from these areas under elevated normal stress in the laboratory. Using the measured fracture surface profile, we generate upscaled fractures and perform numerical simulations to visualize fluid flow and electric current. Finally, we will compare the permeability-resistivity relationships on three scales: laboratory scale, intermediate (numerical model) scale, and field scale. |