WETTING AND NONWETTING FLUID DISPLACEMENTS IN POROUS-MEDIA

The understanding of simple laminar flow in tubes has often been used to interpret the more complicated flow in porous media. A study of the motion of two immiscible liquids in closed tubes with relatively larg e diameter (> 0.3 cm i.d), was conducted in order to examine the influ ence of wetting and nonwetting liquids on the flow behavior. The resul ts indicate that the wetting properties of the fluids with regard to t he tube wall have a major efffect on the formation and motion of long bubbles. A physically based model was used to predict the velocity and the conditions for no motion of bubbles and drops in tubes. These res ults were used to interpret the nature of oil and water flow in porous media. Experiments in which the wetting liquid was displaced by the n onwetting, or vice versa, were conducted by injecting the displacing l iquid at a constant flux at the center of a two-dimensional chamber sa turated with the displaced liquid. The influence of wetting-nonwetting characteristics on the quantity of liquid displaced, the shape of the interface between the two liquids, and the interpretation of the no m otion radius in a closed tube to the case of a porous medium are discu ssed. It would appear that the no motion radius gives a good indicatio n of the minimum width of a nonwetting penetrating finger and the maxi mum width of nonwetting ganglia left by drainage.