Method of moderate water injection and its application in ultra-low permeability oil reservoirs of Yanchang Oilfield, NW China

Xiangzeng WANG,Hailong DANG,Tao GAO

Table 2 Basic parameters of simulation model.

Parameter Value Parameter Value Porosity of matrix 4.58% Reservoir thickness 8 m Permeability of matrix 0.25× 10-3 μm2 Oil saturation 58% Porosity of fracture 0.1% Density of water 1.01 g/cm3 Permeability of fracture 500× 10-3 μm2 Oil/water viscosity ratio 3.5 Density of crude oil 0.86 g/cm3 Oil-water inter- facial tension 40 mN/m Initial formation pressure 12 MPa Bottom hole pressure of oil well 3.5 MPa Starting pressure gradient of oil phase 0.04 MPa/m Starting pressure gra- dient of water phase 0.01 MPa/m Stress sensitivity coefficient of matrix permeability 0.017 MPa-1 Sensitivity coeffi- cient of fracture permeability 0.065 MPa-1 Water flooding volume 10 m3/d