A study of film transport in capillaries with an angular cross-section

his study is concerned with the interfacial and transport phenomena of wetting liquids in the edges of noncircular capillaries. Applications of this study relate to two-phase and three-phase flow in porous media, typically, in the process of oil recovery by waterflooding, and tertiary gravity drainage.;Improvements were made to the theory that predicts the imbibition rate of a wetting liquid in the edges of a square capillary tube occupied predominantly by a gas phase. Very good agreement between the theoretical predictions and the experimental results was obtained. The effect of pore structure and injection rate on the dynamics of the transport of the wetting liquid in the pore edges during imbibition-type displacement has been disclosed by further theoretical analysis and experiments in a throat-pore capillary model.;Theoretical considerations of gas/water, gas/oil and oil/water capillary pressures as functions of the interfacial curvatures, the wettability of the solid, the geometry of the edge and of the water saturation, led to an improved understanding of the mechanism of the formation of an oil film in an edge of a noncircular pore, in waterwet porous media. The theoretical predictions are supported by the observations of imbibition of nonspreading oils over water present in the edges of a two-dimensional glass micromodel and the experiments in a square capillary tube.;The unsteady-state single film flow problem and the constant saturation double film flow problem by gravity drainage in the edges of a square capillary tube were analyzed theoretically. The relative permeability of the wetting phase in single film flow is related to the square of the wetting phase saturation in the corners. The lubricating effect of the water film in double film flow has been analyzed numerically. It has been found that the relative permeability to oil phase in double film flow is a function of water saturation and viscosity ratio. The theoretical predictions were confirmed by the experimental results of film flow carried out in square capillaries.;The retention of wetting liquids in the edges of a square capillary after slow displacement by an immiscible "non-wetting" fluid were measured as a fraction of the cross-section of the square capillary occupied by the liquid. The retention of a wetting phase from air-wetting liquid systems is controlled by capillarity and rate (viscous) effects are of negligible influence when the displacement speed is small...