基于渗透率张量的各向异性油藏两相渗流数值模拟

针对油藏中存在的渗透率各向异性问题,建立全渗透率张量的油水两相渗流数学模型,利用有限元方法在空间域上进行离散,采用隐式差分格式在时间域上离散,得到地层中不同位置处的压力和含水饱和度变化规律。结果表明:各向异性油藏中的注水前缘与各向同性油藏有明显不同,主要沿渗透率主值较大的方向推进;渗透率主值较大方向与注采井连线夹角较小,注入水推进较快,生产井见水较早;注入水前缘的前进方向和速度受各向异性地带渗透率主轴方向和渗透率主值的影响,各区域内注入水沿渗透率主值较大的方向驱替速度较快。

Numerical simulation for two-phase flow in heterogeneous reservoirs based on full permeability tensor

Considering the anisotropic permeability distribution with different principal directions in reservoirs,the mathematical model for oil-water flow in a heterogeneous reservoir with full permeability tensor was established.The equations were discretized by using Galerkin finite element method in space domain and by using backward difference method in time domain.Finally,the formation pressure at different locations and changes rules of water saturation were given.The results show that the waterfront of the anisotropic reservoir is obviously different from that of the isotropic reservoir.The waterfront direction is along the principal direction of the larger permeability.The smaller the angle of the lager permeability principal direction and the line between the injection well and the production well,the earlier the production well meets water.The direction and velocity of the waterfront in the heterogeneous reservoirs can be obviously affected by the principal axis direction and the principal value of the permeability.In each anisotropic region,oil is driven by water faster along the larger permeability principal direction.