Importance of flow condition on seismic waves at a saturated porous solid boundary

Abstract

The deformation of poroelastic saturated media due to passing seismic waves results in coupled solid–fluid motion. Energy losses arise due to the viscous flow of the fluid with respect to the solid matrix. This implies that the flow condition at a saturated porous solid boundary might play a key role in seismic reflection and transmission. A detailed investigation is therefore carried out in this paper to verify this inference. The problem treated herein corresponds to the reflection and transmission of waves obliquely incident at an interface between fluid-saturated porous media and one-phase elastic fluid media. The interface is considered to be either permeable or impermeable to include the effect of flow condition. Based on the theoretical formulation derived, numerical investigations are carried out on the variations of the reflection and transmission coefficients with the angle of incidence as well as the frequency for different interface flow conditions. In addition, the behavior of permeability and porosity effects in the two interface cases is discussed. The results indicate that the effect of the interface flow condition is significant on the reflection and transmission characteristics, especially on the generation of the second kind of compressional waves. A comparison between our theoretical results and the reported experimental observation shows an essential agreement though the physical models considered are different.