Effect of temperature on the oil-water relative permeability for sandstone reservoirs

摘要

Temperature has a significant effect on oil-water relative permeability, which is very important in reservoir development. Considerable controversy persists regarding the effects of temperature and concerning how to obtain representative relative permeability curves. This work studies the effect of temperature on the oil-water relative permeability of tight sandstone and analyzes the influences of absolute permeability, clay mineral content, and pore throat structure on relative permeability curves at different temperatures. The results indicate that irreducible water saturation increases linearly with temperature increase, while residual oil saturation decreases nonlinearly with temperature increase. In addition, when temperature increases, both oil and water relative permeability increase under the same water saturation and the crossover saturation moves rightwards, which indicates that the system becomes more water-wet. Due to the significant effect of temperature on relative permeability, experimental results from lab tests cannot accurately reflect fluid flow characteristics under the reservoir condition. In order to overcome this problem, this paper proposes a novel method to translate lab results into reservoir values by combining the Johnson-Bossler-Naumann (JBN) technique and the empirical method. The comparison between the calculation and the lab results is consistent. The conclusions of the paper provide a valuable reference for laboratory tests under high temperature, and they can be used for preliminary evaluation purposes.