Wave Propagation in Residual Saturated Porous Rocks - A Multiscale Approach

Abstract

Phase velocities and dispersion of acoustic waves in residual saturated porous rocks are affected by material properties of the solid skeleton (porosity, skeleton and grain stiffness) and properties of the inherent pore fluids (viscosities, bulk moduli) as well as the morphology of saturation. A multiscale continuum model describing acoustic waves in porous rocks saturated with a continuous gas phase and a discontinuous liquid (water or oil) phase is analysed. Dispersion relations for the P-waves are shown and compared with Biot's poroelastic approach. It is observed, that negative partial densities occur close to the resonance frequency of the liquid phase. The analogy with acoustic metamaterials is discussed.