薄差储层油水渗流规律研究

Study on oil /water percolation in thin and poor pay zone

应用岩心水动力实验数据归一化得到薄差层油水相对渗透率曲线。引入有效驱动系数,对驱油效率、含水上升规律、不同条件下采液采油指数的变化规律以及影响因素进行分析。研究表明:薄差层两相共渗区范围窄,驱油效率低,其相渗特征主要受表外储层影响;含水上升率在含水率为40%时达到最大,且分布不对称;较高的油水黏度比、较大的有效驱动系数有利于提高无因次采液指数、采油指数,因此薄差层开发应有效提高低含水期采出程度。

Oil-water relative permeability curve of thin and poor pay zone was obtained through normalization of hydrodynamic experimental data. By introducing effective driving coefficient,this paper analyzed oil displacement efficiency,the rising pattern of water cut,and the variation rule and influencing factors of fluid productivity index and productivity index under different conditions. Study shows that for thin and poor pay zones,the two-phase percolation zone is narrow,displacement efficiency is low,and relative permeability is mainly influenced by contingent reservoirs; water cut increasing rate is the highest at 40% water cut and displays unsymmetrically,presenting distinct difference with that of conventional reservoirs where the highest is at 50% water cut and the curve is symmetrical; higher oil/water viscosity ratio and effective driving coefficient are helpful to increasing dimensionless fluid productivity index and productivity index,therefore improving the recovery percent of reserves in low water cut period shall be an effective way of developing thin and poor pay zones.