Effects of mesoscopic flow on ultrasonic velocities

Abstract

Mesoscopic flow is a significant mechanism of fluid-related seismic attenuation in partiallysaturated rocks. Attenuation due to this mechanism is controlled by spatial distribution of fluids.To study this effect in the laboratory we quantify mesoscale fluid distribution from CTscans and compute its associated acoustic signatures using poroelasticity theory. By comparingthese theoretical estimates with experimentally measured velocities, we find thatmesoscopic flow underestimates elastic wave attenuation at ultrasonic frequencies.