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# [SCG57-10] Estimation of fluid distribution from seismic velocity and electrical resistivity

Keywords:seismic velocity, resistivity, fluid

We propose a new method for estimating the amount of fluid from seismic velocity and resistivity. It utilizes an empirical relationship between the normalized resistivity and crack density parameter, which was obtained from measurements of elastic wave velocity and electrical conductivity in a brine-saturated granitic rock under confining pressures (Makimura and Watanabe, Poster session). Resistivity is normalized by the fluid resistivity. If we assume a lithology for the study region, we can estimate the crack density parameter from observed velocity. Using the empirical relation, we can obtain the normalized resistivity. Comparing the normalized resistivity with observed resistivity, we can obtain the fluid resistivity. If the fluid resistivity is an unrealistic value, we must modify the assumed lithology. Both the lithology and fluid resistivity can be constrained through these procedures.

The applicability and limitation of the empirical relation should be studied both experimentally and theoretically. In experimental studies, the relation should be studied in different rock types. A theoretical work on the network of grain boundary cracks will give us a basis of the relation.