Acoustic wave propagation in porous media; velocity, attenuation, permeability, and porosity inversion.

摘要

Acoustic wave propagation in porous media is formulated according to the Biot theory. The theory is extended for causal wave propagation in a dissipative porous medium with arbitrary pore size distribution. Using Kramers-Kronig relations, it is demonstrated that previous Biot models with slightly inelastic frame assumption is not causal.;A one-dimensional forward model is developed for the acoustic wave propagation in layered marine sediments. An iterative inverse method is also introduced to determine frequency dependent compressional wave velocity and attenuation in a layered medium. Approximate relations are proposed to determine porosity and permeability from the velocity and attenuation data.;Low frequency (300 Hz-30 kHz) measurements of compressional wave velocity and attenuation are performed in saturated beach sand. Biot formulation of acoustic wave propagation and prediction of viscous losses for saturated sandy sediments are confirmed experimentally. Consequently, it is demonstrated that acoustic remote sensing of porosity and permeability is possible.