ABSTRACT
This chapter presents very simple descriptions of porosity–pressure waves and saturation waves. It includes an introductory description of the coupling between these waves. The first descriptions of porosity–pressure waves were developed in 1993. The chapter investigates very simplistic approximations of the theory under the assumption that saturation waves are strongly coupled to porosity–pressure waves. This assumption is based on experimental observations that clearly illustrate that saturation waves are completely dominant over viscous fingering in the presence of porosity–pressure waves. Experimental observations indicate that the porosity and saturation waves are so strongly coupled that the passing of porosity waves causes dispersion to completely dominate viscous fingering. A standard technique to analyse waves governed by a wave equation is to substitute a trial solution, typically a homogeneous plane wave, into the wave equation to obtain a dispersion relation. An important experimental observation is the coupling between porosity waves and saturation waves.
