Oil mobility in a saturated water-wetted bed of glass beads

Abstract The mobilization of an oil bank in a packed bed of glass beads saturated with an aqueous phase has been studied both theoretically and experimentally. The size of the glass beads was varied in the range between 0.5 and 5 mm. Two oils (hexadecane and hexane) with viscosities different for an order of magnitude and densities smaller than that of water have been used. A few more runs have been carried out using perchloroethylene (PCE), with density greater than that of water. The interfacial tension in the aqueous phase was varied in a quite large range (0.38–39.1 dyn/cm) by adding surfactants to the water. The glass assembly made it possible to follow the evolution of the dyed oily phase by the use of a digital camera. A very simple stochastic model for describing the porous structure of the packed bed made it possible to set a criterion for determining the probability of mobilization of ganglia which are produced by the fragmentation of the oil bank. The same model permits also to estimate the probability function of the velocity of a ganglion of an assigned size.