Numerical Analysis Of Wavefields In Composite Frozen Porous Media.

Abstract

Using a physical model presented by some of the authors in previous works, we analyze
the propagation of elastic waves in multiphase porous media composed by two weakly coupled
solids, saturated by a viscous single-phase fluid. The model predicts the existence of three
compressional and two shear modes of propagation. The set of partial differential equation is
solved using an iterative domain decomposition finite element procedure in the space-frequency
domain, which allows us to include the frequency dependence of dissipation, mass and viscous
coupling coefficients in the high frequency range.
We focus the attention in the numerical simulation of ultrasonic wave generation and propagation
in a small sample of a partially frozen sandstone (permafrost) with non-uniform waterice
distribution, to analyze the correlation between the heterogeneities, scattering and wave
mode conversion effects taking place under these conditions.