存在启动压力梯度时储层动用半径的确定

The determination of drainage radius for reserviors with a start-up pressure gradient

稠油在多孔介质中渗流偏离达西定律,具有启动压力梯度,只有当驱动压力梯度超过启动压力梯度时稠油才开始流动。基于室内物理模拟实验结果,得到了启动压力梯度与流度的关系式;在此基础上,从多孔介质渗流理论出发,通过理论推导,得到了存在启动压力梯度时储层动用半径的数学模型。实例应用结果表明,本文提出方法简单实用,分析结果与油田实际情况基本一致。

Heavy oil flow in porous media is characterized by deviation from Darcy＇s law and a startup pressure gradient, and it begins only when the driving pressure gradient is higher than the startup pressure gradient. A relational expression between start-up pressure gradient and fluid mobility has been obtained on a basis of physical laboratory simulations. Then a mathematical model of the drainage radius for reservoirs with a start-up pressure gradient is derived from the seepage theory of porous media. The application results show that this method is simple and practicable, and that its analyses are largely consistent with the real situations in oilfields.