Abstract: A modelling method having application to petroleum production, soil cleaning, etc. for optimizing faster and more realistically the displacement conditions, in a porous medium wettable by a first fluid (water for example), of a mixture of fluids including this wetting fluid, another, non-wetting fluid (oil for example) and a gas.

Abstract: The invention concerns a method comprising experimentally determining the variation curve of capillary pressure in pores on the basis of saturation with respect to liquid phases, modelling the pores of the porous environment by capillary distribution with fractal distribution while taking into account in the case of a three-phase water (wetting fluid)-oil-gas mixture for example stratification of the constituents inside the pores, with water in contact with the walls, gas in the centre and oil forming an intervening layer, determining, on the basis of said capillary pressure curve, values of fractal dimension corresponding to a series of given values of saturation relative to the liquid phase, modelling hysteresis effects modifying the mobile saturation levels of fluids actually displaced in the sample which vary in the course of drainage and imbibition cycles, modelling relative permeability levels directly in the form of analytical expressions depending on the different values of fractal dimension obtained