10:15 〜 10:30
[SEM14-06] How hydraulic conductivity can be derived from resistivity and seismic data? -a case study from geophysical logging in granitic area, Japan -
キーワード：比抵抗、地震波速度、透水係数
It is necessary to understand distribution of hydraulic permeability of bedrock in the deep underground. In this study, the author aims to construct a rock physics model for estimating the permeability of fractured granite using integrated geophysical exploration. A new proposal is based on two-step models: a matrix model with small inclusions (i.e., microscopic fractures), and a bulk rock model with larger inclusions (i.e., macroscopic fractures). The author applies this matrix model to the rock mass without macroscopic fractures, then apply the model to the fractured granite. The theoretical values of the seismic velocity and resistivity are calculated by using the equations for Kuster-Toksoz model and the modified Archie's equation, respectively. The permeability can be estimated from the parameters in the modified Archie's equation. Based on the field geophysical data, the validation of this new rock physics model should be confirmed. The rock physics model for seismic velocity and resistivity was constructed based on a logging data obtained at the Toki granite area, Gifu prefecture. The model is also applied to the other logging data in the same area. As a result, the predicted fracture porosity and bulk permeability showed good agreement with the measured ones. The correspondence indicated the validity of the proposed rock physics model.