Estimating the effects of pore geometry and pore fluid species on elastic wave velocity dispersion in rocks using microstructural models

Abstract

An understanding of the nature of possible velocity dispersion mechanisms is required for the quantitative interpretation of reflection seismic and acoustic well log data in terms of laboratory measurements of elastic wave velocities. Two mechanisms commonly used to explain dispersion in liquid-filled porous rocks are Biot dynamic poroelasticity and local flow. The results of Endres and Knight (1997) provide a basis for a consistent comparison of these two mechanisms using a single inclusion-based model to describe a porous medium. From the modeling study presented in this paper, it was found that both pore geometry and pore fluid properties significantly affect the absolute and relative magnitude of the dispersion produced by these two mechanisms.