Oil-water relative permeability and its influencing factors in single fracture-vuggy

Key words:  reservoir  single fracture-vuggy  vuggy diameter  oil-water relative permeability  residual oil saturation

Abstract:

The complex fracture-vuggy system can be simplified as basic combination of fractures and caves. The two-phase flow laws were researched by analyzing water-oil relative permeability curves. Based on the reservoir characteristics of the carbonate rock of practical oilfield, single fracture-vuggy organic glass models with different vuggy diameter were made. Oil-water relative permeability curves were measured by using steady-state method. The influence of vuggy diameter, fracture-vuggy dip, oil-water viscosity ratio and injection rate on oil-water relative permeability curves was studied. The results show that in the models composed of single fracture-vuggy, the shape of oil relative permeability curve changes from linear type to down-concave type with the increase of vuggy diameter. The shape of water relative permeability curve is up-concave type, and the curvature of the curve increases with the vuggy diameter increasing. Residual oil saturation decreases with the increase of vuggy diameter, fracture-vuggy dip and injection rate, and the decrease of oil-water viscosity ratio.