Single-Phase (Brine) and Two-Phase (DNAPL–Brine) Flows in Induced Fractures

Abstract

This study reports an investigation on the characteristics of single-phase (brine) and two-phase (DNAPL–brine) flows in induced fractures. The fracture aperture and fluid phase distributions were determined using X-ray computer tomography. In the single-phase flow tests, the pressure gradient across the induced fractures increases linearly with increasing flow rate. However, models based on the measured aperture do not yield a consistent match with the experimental data because the effect of pressure losses due to aperture variation and undulation are not taken into account. In the two-phase flow tests, the measured phase distributions reveal that the flow pattern is dominated by a dispersed or mixed flow in which either DNAPL or brine phase is discontinuous. The channel flow pattern, in which DNAPL and brine phases are continuous in the fracture and well represented by the widely used Romm’s relative permeability relationship was not observed in this study. In contrast, a Lockhart–Martinelli-type correlation developed for gas–liquid flow in pipes was found to match the pressure gradient and phase saturation results obtained from the laboratory tests.