基于Logistic模型的驱油效率与注入倍数关系定量表征方法

Quantitative Research of Relationship Between Oil Displacement Efficiency and Pore Volume Injection Ratio Based on Logistic Model

在水驱开发油田中,驱油效率是影响油藏采收率的重要参数之一,而孔隙体积注入倍数是直接影响油藏波及区域内最终驱油效率的决定性因素。采用相渗指数表达式的渗流方程,结合B-L理论及Welge方程推导驱油效率与孔隙体积注入倍数的半定量关系,该关系曲线满足生命旋回理论。根据Logistic增长规律推导了两者的定量关系,并在数值模拟中进行了较好的验证,利用此方法可求得一定波及体积范围内理论采收率条件下的最大孔隙体积注入倍数。随着油田陆续进入高含水阶段,驱油效率定量表征方法对于评价水驱油藏开发效果、认识油藏剩余潜力具有重要意义。

Oil displacement efficiency is one of the important parameters affecting the oil reservoir recovery,and the pore volume injection rate is the decisive factor that directly affects the ultimate oil displacement efficiency in the sweep zone.The semi quantitative relationship between the displacement efficiency and the injection volume of pore volume is derived by using the percolation equation expressed by the phase permeability index,combining with the B-L theory and the Welge equation.The relation curve satisfies the life cycle theory and the quantitative relation expression between them is deduced according to the law of Logistic growth.At the same time,the optimal pore volume injection ratio is determined by the two-order derivative curve.With the oil field entering the high water cut stage,the quantitative evaluation method of oil displacement efficiency is of great significance for evaluating the development effect of water flooding reservoir and tap the potential of the reservoir.