A Steady-State Technique for Measuring Oil-Water Relative Permeability Curves at Reservoir Conditions

Abstract

ABSTRACT A steady-state technique for measuring oil-water relative permeability curves is presented. The technique allows measurements to be made on preserved core samples at reservoir temperature and pressure, using reservoir fluids. Live oil and brine are circulated simultaneously through the core in a closed system, and relative permeability data are taken when conditions in the core have stabilized. A series of five to ten flow rate ratios is normally used, providing data at saturations ranging from irreducible water to residual oil. Saturations are determined by monitoring the oil content of a high-pressure oil-water separator in the system. The technique is particularly useful for heterogeneous cores and cores with mixed wettability, where dynamic displacement tests can give inaccurate relative permeability data. The use of reservoir conditions and live fluids is preferred because the true wettability of reservoir rocks may not be preserved in tests performed with dead crude or at room temperature. Data is presented which demonstrates the application of this steady-state technique to the study of relative permeability hysteresis.