Pattern of Two-Phase (DNAPL-Water) Flow through Single Fracture under Temporal Evolution of Aperture

Abstract

Coupling of two-phase flow with mechanical deformation has important applications in many fields, including dense nonaqueous phase liquid (DNAPL)–water transportation through the subsurface. To understand and couple the different processes, numerical model studies are inevitable at all temporal and spatial scales. This study presents the characterization of DNAPL and water flow in a fracture under confining and fluid pressures. A comprehensive and simplified mathematical model and the conditions under which DNAPL will enter an initially water-saturated fracture under deformation are discussed. A numerical model to predict the quantity of each phase of their saturations is developed. The effect of varying confining stresses on the traverse time of DNAPL across a fractured aquitard is studied. The sensitivity analysis for physical and hydraulic properties, such as apertures, fracture inclination, and fluid and confining pressures, are performed and discussed. The temporal evolution of aperture is necessary to know the proper flow pattern of fluids within a fracture in a multiphase system. These studies are relevant for DNAPL trapped in fractures with very small aperture that can bring changes to flow pattern under deformation.