Tracer-detection and structure of stationary lamellae during foam flow through Berea sandstone.

摘要

This work examines the role of trapped gas on foam flow in porous media. This phenomenon is examined in two different ways. First, gas-phase tracer experiments have been used to measure the trapped gas fraction. Included with this work is the necessary mass-transfer modelling for the interpretation of the experimental tracer histories which are obtained. Second, microscopic lamella profiles have been evaluated in smooth slits and tubes and also in constricted slits.;The augmented Young-Laplace equation has been solved for lamellae in smooth tubes and slits and in constricted slits. Calculated profiles are compared to approximate profiles which are commonly used. A new approximation for lamella liquid volume is presented and found to give excellent agreement with the values from the exact calculation. The angle of contact of a lamella with the wall was found to be 90;The experiments used to measure the trapped gas fraction involve a unique experiment involving dual gas tracers. Two different gas-phase tracers are introduced to the core at the same time. The tracers have different water solubilities and diffusion coefficients. They therefore exhibit different effluent histories. The difference in the effluent histories of these two tracers says a great deal about the mass-transfer effects which previous investigators have chosen largely to ignore. The two tracer histories are curvefit simultaneously to a mass-transfer model which includes three unknown parameters (