低渗透砂岩油藏改进水驱曲线含水率预测方法

Water-cut prediction method of improved waterflooding characteristic curve in low-permeability sandstone reservoirs

针对大庆外围低渗透油田中高含水期水驱曲线不出现明显直线段问题,统计343条相渗曲线,基于油水两相渗流规律,建立了改进的水驱曲线含水率预测方法。研究结果表明:对油水相对渗透率比值与含水饱和度在半对数坐标下进行二次式关系拟合,拟合精度可大幅提升。应用矿场实际资料对改进的水驱曲线的拟合精度进行检验,结果表明,其拟合精度高于其他四种水驱曲线,含水相对误差在2%以内。因此,可应用新建立的改进水驱曲线对外围低渗透油田含水进行预测,该方法对同类油田的指标预测具有重要指导意义。

Aiming at the problem that there is no obvious straight-line segment in the waterflooding characteristic curve of lowpermeability oilfields in the periphery of Daqing in the middle and high water-cut period,343 oil-water phase permeability curves were counted.Based on oil-water two phase seepage laws,an improved water-cut prediction method of water drive curve was established.The research results show that the fitting accuracy of the quadratic relationship between oil-water relative permeability ratio and water saturation in semi-logarithmic coordinates can be greatly improved.The actual data of oilfields was used to test the fitting accuracy of the improved water drive curve.The results showed that the the accuracy of the improved water drive curve was higher than the other four waterflooding characteristic curves,and the relative error of water cut was less than 2%.Therefore,the newly established improved water drive curve can be used to predict water-cut in peripheral low-permeability oilfields of Daqing.This method has important guiding significance for the index prediction of similar oilfields.