考虑渗透率张量的各向异性油藏流线模拟方法

针对各向异性油藏,考虑全张量形式渗透率,建立三维两相不可压缩流体流线模拟方法。采用十九点差分格式对压力方程差分离散并进行求解得到压力场,对全张量渗透率下运动方程求解得到速度场,采用Pollock方法确定并追踪流线,最后根据一维水驱油理论得到任一流线内的含油饱和度分布。不同渗透率张量油藏模型计算结果表明:油藏压力沿最大主渗透率方向传播较快;由于流速计算时交叉项的引入,流线与压力梯度方向一般不一致;注采井方向与最大主渗透率方向垂直布置可有效减轻注入水沿最大主渗透率方向的突进,使流线在整个油藏中分布更加均匀,改善水驱开发效果。

A streamline simulation method for heterogeneous oil reservoirs considering permeability tensor

Considering the anisotropic permeability in oil reservoirs, a streamline simulation method with full permeability tensor was established. A nineteen-point finite-difference scheme was used in pressure equation to calculate the pressure distribution. The velocity profile was calculated by Darcy ''s law with full permeability tensor, and the streamline was traced by Pollock method. The oil saturation at every point on each streamline was calculated based on one dimensional water displacement theory. The calculated results for reservoirs with different permeability tensor show that pressure propagates faster along the direction of maximum principal permeability. The orientation of the streamlines and the direction of pressure gradient are generally inconsistent due to the introduction of a cross term during the velocity calculation. If injector and producer are placed perpendicular to the direction of maximum principal permeability, it can make the streamline distribution more evenly throughout the reservoir, which can improve the efficiency of water flooding.