Porous Media, Permittivity, Fluid Permeability of Shales and Seismic Coda

This chapter discusses the characteristics of porous media and seismic coda waves. One of the important examples of a porous medium is oil shale. One is the permittivity and conductivity of the porous medium as given by Archie's law. The other is the flow of liquid such as oil through the porous medium as given by Darcy's law and "fluid" permeability, which is different from the "magnetic" permeability concept we commonly use in electromagnetic studies. The study of porous media is closely related to the "percolation theory" and the "fractal". The permeability of a porous medium such as shale is a measure of the resistance to the flow of a fluid through the medium. The chapter shows typical seismic waves observed at the receiver. The study of the P‐coda, S‐coda, and Rayleigh‐coda is critical to the understanding of the total seismic radiation.