中高含水期新型水驱特征曲线关系式

A new relational expression of water drive characteristic curve at medium and high water cut stages

在油田开发的见水初期和特高含水阶段,油水相对渗透率比值与含水饱和度在半对数坐标中不再呈线性关系。根据油水相对渗透率比值与含水饱和度的关系曲线特征,提出新的函数模型,利用该模型的非线性性质,采用牛顿算法优化求解,得出适合中、高含水阶段油水相对渗透率比值与含水饱和度与含水饱和度关系表达式,并在此基础上拟合出适合中、高含水期油田的新型水驱特征曲线。以贝尔油田某区块、榆树林油田东某区块、西峰油田庄某区块、和PL19-3油田某区块的油藏生产数据为例进行实例验证,该方法预测的极限可采地质储量与其他方法基本一致,具有较强的适用性,有助于指导油田开发实践。

At the initial stage of water breakthrough and ultra-high water cut stage of oilfield development,the relation between oil-water relative permeability ratio and water saturation is no longer linear in semi-logarithmic coordinate.According to the characteristics of the relation curves between oil-water relative permeability ratio and water saturation,a new function model is proposed in this paper.This model with nonlinear behavior is solved using the Newton algorithm to derive the relational expression between oil-water relative permeability ratio and water saturation at medium and high water cut stages.On this basis,a new water drive characteristic curve suitable for oilfields at medium and high water cut stages is obtained.Taking the reservoir production data of Beier,Yushulin,Xifeng and PL19-3 oilfields as examples,it is verified that the ultimate recoverable reserves predicted by this method are basically consistent with that by other methods.Thus,the proposed method is very applicable and helpful to guide the practical oilfield development.