oa Simultaneous Inversion of Self-potential for Estimating Hydraulic Parameters and Streaming Current Coefficient

In this study, we develop a 3D inversion scheme for the transient self potential (SP) data to estimate hydraulic conductivity, streaming current coefficient and specific storage. We test our inversion scheme with the synthetic data according to the pumping test. Our inversion could reconstruct the structure of hydraulic conductivity properly. However, the resolution of the estimation image of specific storage is not as clear as the image of hydraulic conductivity. To detect the factor that decides the resolution in the estimation image of the specific storage, we check the variation of the sensitivity of specific storage during the pumping. The specific storage is sensitive just after the beginning and the termination of the pumping. The stage when the specific storage is sensitive has been kept in the shorter duration than the stage of the hydraulic conductivity. The resolution of estimated image would be affected by the pattern of the transient SP data and pumping data. To improve the resolution in the estimation image of specific storage, the inversion of the synthetic transient SP data according to the repetitive pumping and injection is performed. The inversion image of the specific storage was improved under this condition.