二元复合体系相对渗透率曲线测定

DETERMINATION OF THE RELATIVE PERMEABILITY CURVES FOR THE BINARY COMPOUND SYSTEM

二元复合体系相对渗透率曲线在测定上主要存在两方面困难,首先聚合物在孔隙中会发生吸附和滞留现象,使得溶液有效黏度降低;其次二元体系具有乳化作用,计量精度较差.采用稳态法测定了相同渗透率贝雷岩心中水、聚合物和二元复合体系的相对渗透率曲线及不同渗透率贝雷岩心中二元复合体系的相对渗透率曲线.结果表明：高渗透率岩心的水相渗透率上升幅度比低渗透岩心快,高渗透率岩心内的残余油饱和度明显比低渗透率岩心低,说明高渗透率岩心的驱油效果更好;二元复合驱相对渗透率曲线比水驱、聚合物驱相对渗透率曲线的两相跨度都大,右端点更偏右,岩心内部的残余油饱和度更低,说明二元复合驱比水驱和聚合物驱驱油效果更好、采出程度更高.研究结果可准确预测采油速度、最终采收率、含水率,判断油藏润湿性,提供油藏数值模拟参数.

There are two difficulties mainly exist in the determination of the relative permeability curves of the bi- nary compound system ： the one is that the adsorption and retention of the polymer in the pores result in the reduc- tion of the effective viscosity of the solution; the other is that the emulsification of the system makes the measure- ment precision reduced. With the help of the steady-state method, the relative permeability curves of the water, polymer and binary compound systems in Berea core with the same permeability and the curves of the latter with dif- ferent permeability in Berea core are determined. The results show that compared with the low-permeability cores, the rising rate of the water phase permeability is faster and the residual oil saturation is lower in the high-permeabil- ity cores, thus the better displaced effects are proven for the cores with high permeability; the oil-water span in the relative permeability curves of the binary compound flooding is larger than those of the water and polymer ones, and moreover the right points are closer to the right, the residual oil saturations within the cores are rather lower, these conditions proves that the displaced effects and recovery degree of the binary compound flooding are better than those of the water and polymer floodings. The study results can accurately predict the oil production ratio, ultimate recovery factor and water cut, judge the wettability of the oil reservoirs and provide the parameters for the reservoir numerical simulation.