Study on gas-liquid relative permeability experiments of fractured-porous reservoirs

Abstract

For carbonate reservoirs, gas-water and oil-gas relative permeability curve are of importance for parameters calculation in oil-field development, dynamic analysis and numerical reservoir simulation. The oil-gas/gas-water relative permeability curves were measured with unstable method under normal temperature and low pressure, using fifteen artificial fractured cores. The shape and change characteristics of gas/water and oil/gas relative permeability curve were mainly analyzed. The results showed that for the relative permeability curve of water driving gas. The saturation of equal permeability point, the saturation range of two-phase flow region and the displacement efficiency has a good power-function relation with core permeability. In addition, the saturation of equal permeability point, the saturation range of two-phase flow region and the displacement efficiency will decrease with the increasing of core permeability. However, for oil-gas relative permeability curves, the saturation of equal permeability point, the saturation range of two-phase flow region and the displacement efficiency will increase with the increasing of core permeability. It should be noted that the gas relative permeability presents a straight line in the normalized relative permeability curve, which indicates that the main flow is dominated by fracture with low displacement efficiency. The research results provide theory basis for fracture-vuggy carbonate reservoir development and new research idea for the further study of this kind of reservoir.