Velocity dispersion of P waves in sandstone and carbonate: Double‐porosity and local fluid flow theory

Summary Double-porosity theory is developed to describe the Pwaves' velocity dispersion and attenuation phenomena, which are induced by local fluid flow in the heterogeneous fluid-saturated porous rocks. In this paper, plane wave solutions are submitted into double-porosity wave motion equations to estimate P-wave velocity and attenuation in reservoir rocks. Theoretical analysis provides the relationships between P-waves' velocity and attenuation and rock's physical parameters. Biot, BISQ, and doubleporosity theory are compared in investigating P-waves' velocity dispersion in Guang'an sandstone. Double-porosity theory is used to predict P-waves' dispersion trends in low frequency band for a carbonate sample. Comparisons with the broad-band lab data show that double-porosity predictions are in good agreement with experimental observation for P-waves' velocities in seismic band.