A Dynamic Network Model for Imbibition and Film Flow

This book presents a dynamic network model for imbibition, which accounts for complex dynamics of corner film flow, swelling and snap-off. In contrast to previously published models in which length scales for snap-off are either specified a priori or calculated assuming steady-state flow and constant film conductivities, in the present model, snap-off arises as a natural consequence of the fully transient nature of film flow and swelling. The new network model was used to analyse the complex effects of displacement rate, contact angle, aspect ratio and pore and throat shape on macro-scale flow properties, namely relative permeabilities and residual saturation. The computed values of these properties were compared with laboratory measurements reported in the literature for sandstone and carbonate rocks. It was found that in imbibition, the magnitude of rate effects depends largely on the pore-throat ratio of the rock pore space. The higher the aspect ratio, the stronger the rate effects.