Seismic reflection and transmission coefficients of a single layer sandwiched between two dissimilar poroelastic solids

Abstract

The seismic reflection and transmission characteristics of a single layer sandwiched between two dissimilar poroelastic solids saturated with two immiscible viscous fluids are investigated. The sandwiched layer is modeled as a porous solid with finite thickness. The propagation of waves is represented with potential functions. The displacements of particles in different phases of the aggregate are defined in terms of these potential functions. Due to the presence of viscosity in pore fluids, the reflected and transmitted waves are inhomogeneous in nature, i.e., with different directions of propagation and attenuation. The closed-form analytical expressions for reflection and transmission coefficients are derived theoretically for appropriate boundary conditions. These expressions are calculated as a non-singular system of linear algebraic equations and depend on the various parameters involved in this non-singular system. Hence, numerical examples are studied to determine the effects of various properties of the sandwich layer on reflection and transmission coefficients. The essential features of layer thickness, incident direction, wave frequency, liquid saturation and capillary pressure of the porous layer on reflection and transmission coefficients are depicted graphically and discussed. The analysis shows that reflection and transmission coefficients are strongly associated with incident direction and various properties of the porous layer.

Modeling the effects of fracture infill on frequency-dependent anisotropy and AVO response of a fractured porous layer

“…In addition, current analysis on seismic AVO signatures normally uses single interface reflection model or normal-incidence reflection approach. This forward modeling has not accurately considered the influences of both the stratified structure and the attenuation and dispersion of complex stiffness tensors from rock physics simulation in the computations of angle-and frequencydependent reflection coefficients (e.g., Rüger et al 1997;Ren et al 2009;Liu et al 2011;Dupuy and Stovas 2014a, b;Zhao et al 2015;Kumari et al 2017;Kumar et al 2018;He et al 2019).…”