变黏度聚合物段塞交替注入驱油效果评价

Oil displacement efficiency evaluation of variable viscosity polymer slug alternative injection

针对聚合物单一段塞注入易发生返转、高渗层突进等问题,探索通过变黏度聚合物段塞交替注入改善非均质油层的驱油效果。对非均质油层依次交替注入不同黏度的聚合物段塞,高黏度聚合物段塞优先进入高渗层,降低了高渗层流速,迫使后续低黏流体进入与之较为匹配的低渗层,使高、低渗层驱替剂流度差异减小。实验结果表明,交替注入增加了低渗层的吸液量,低渗层分流率曲线形态由"∧"字型向"∩"字型转变,交替注入方式聚驱采收率提高值高于单一段塞注入方式,并且使聚合物用量降低了四分之一。

Aiming at the issues caused by polymer single-slug injection,to improve the oil displacement efficiency in heterogeneous layers through variable viscosity polymer slug alternative injection technique was addressed in this paper.Successive injecting the polymer slugs with different viscosities into the anisotropy reservoirs make the high viscosity polymer flow into high permeability layers to decrease the velocity of fluid,and then make sure the following low viscosity fluid drain to zones with low permeability,which could narrow the mobility differences between reservoirs of high and low permeability.The experimental results show that alternative injection raises the amount of fluid absorption in layers of low permeability,and the diversion ration carves in these layer transfers from shape ＂∧＂to ＂∩＂.The increase of EOR by alternative injection method is higher than that by single slug injection,and the former technique also reduce the polymer consumption by a quarter.This research provides a reference for optimizing the injection method of polymer flooding technique.