Constant-pressure Measurement of Steam-water Relative Permeability

A series of steady-state experiments have established relative permeability curves for two-phase flow of water in a porous medium. These experiments have minimized uncertainty in pressure, heat loss, and saturation. By attempting to maintain a constant pressure gradient, the experiments have provided a baseline from which to determine the effect of temperature on relative permeability. The use of a flexible heater with an automatic control system made it possible to assume negligible phase change for the mobile fluid. X-ray computer tomography (CT) aided by measuring in-situ steam saturation more directly. Mobile steam mass fraction was established by separate steam and water inlets or by correlating with previous results. The measured steam-water relative permeability curves assume a shape similar to those obtained by Corey (1954) for the simultaneous flow of nitrogen and water. Close agreement between the curves by Satik (1998), Mahiya (1999), and this study establishes the reliability of the experimental method and instrumentation adopted in these experiments, though some differences may bear further investigation. In particular, the steam phase relative permeability appears to vary much more linearly with saturation than does the water phase relative permeability.