Transient Self Potential Inversion for the Simultaneous Estimation of Hydraulic Conductivity and Specific Storage

Abstract

Summary In this study, we developed an inversion scheme for the estimation of hydraulic conductivity and specific storage from transient SP profile. For the calculation of the sensitivity matrix of a transient SP profile, an adjoint state method is employed. The sensitivity of hydraulic conductivity and specific storage is time variant. The time when each parameter becomes most sensitive is different from each other. This feature would make the simultaneous estimation of hydraulic conductivity and specific storage possible from the transient SP profile. We simulate SP profiles according to the injection test with the heterogeneous subsurface models of hydraulic conductivity and specific storage. We tried to reconstruct the given model from the synthetic transient SP profile. Our inversion scheme could detect the anomalies of the hydraulic conductivity and the specific storage. From this result, we conclude that the transient analysis of SP profile would be a useful method for the estimation of both hydraulic conductivity and specific storage.