Résultats expérimentaux récents sur les écoulements diphasiques en milieu poreux

It is pointed out that there is no known way of providing for the replacement of one fluid by another in a porous medium sample, even with simple flow in one direction only. An account is given of observations on the displacement of a wetting fluid by a non-wetting immiscible one and it is shown that permeability rise can be plotted in terms of capillary pressure, from which one can deduce permeability rise in terms of the threshold radii of channels playing an effective part in the fluid flow and interpret these results from the angle of velocity distribution in a steady single-phase flow. It is shown that a porous medium can thus in practice be divided into several channel systems in which each channel is typified by its threshold dimensions and gives the medium a certain degree of porosity and permeability. In each such system, the displacement of one fluid by another may be comparable in practice to that due to the effect of a piston, and the overall phenomenon may be the sum of the individual phenomena occurring in each such system