Research on the Influence of Capillary Forces on a Liquid Flow in Fractures with Nonuniform Apertures

Abstract

A physicomathematical model of a two-phase liquid flow in a discrete fracture network—taking into account a nonuniform fracture aperture, flow exchange between fractures, capillary and gravitational forces—is presented. Capillary forces are described by the Young-Laplace model that takes into account the rock wetting angle and surface tension. The influence of the structure of the conducting channels in a fracture, capillary and gravitational forces, and the pressure gradient, as well as the water-and-oil viscosity ratio on the flow dynamics and the oil recovery factor, is explored. It is shown that capillary forces and the structure of channels in a fracture can play a decisive role in the process of oil displacement by water.