An experimental study of immiscible displacement with an unfavorable mobility ratio in porous media

The displacement of one fluid by another (miscible or immiscible) in porous media is an important phenomenon that occurs in groundwater movement and oil reservoir engineering. Practical examples are water flooding, solvent flooding, saltwater intrusion into coastal aquifers, and coning. Experiments are presented on viscous fingering in a glass bead packed porous medium model. They cover the entire scope of finger development from the incipient fingers predicted by Chuoke's theory to a parallel‐sided single finger. As incipient fingers move, they decrease in number. Both decay and merging are simple viscous effects. Results of several experiments show that the rate of growth develops almost immediately, well before the finger is parallel sided. The mechanisms of wavelength generation and degeneration are discussed on physical grounds.