Drainage Relative Permeabilities Obtained from Steam-Water Boiling Flow and External Gas Drive Experiments

Abstract

Steam water relative permeability data are required for mathematical models of two phase geothermal reservoirs. In this study, drainage steamwater relative permeabilities were obtained from steady, two phase, non-isothermal bench scale flow experiments. Liquid water saturations were measured along the length of synthetic sandstone cores using an internal capacitance probe. In addition, nitrogen water relative permeabilities were obtained for synthetic sandstone core. These isothermal, unsteady gas driven experiments were used to determine drainage relative permeabilities and calculated water saturations. Experiments were conducted at several temperatures and pressures. It was established that nitrogen water relative permeability was not strongly temperature dependant below 300°F at confining pressure less than 300-500 psig. A comparison of steam water and nitrogen water relative permeability data indicated that at high water saturations, the external gas drive (nitrogen water) gas relative permeabilities were larger than the internal gas drive (steam water) steam relative permeabilites.