聚驱中后期气聚交替注入提高驱油效果试验

Investigation of the technique of gas/polymer alternate injection at the middle-late stage of polymer flooding

为改善聚驱效果,提高中、低渗透层的采收率,在室内,对聚驱中后期气聚交替注入技术的气液比、段塞组合、聚合物相对分子质量、聚合物溶液质量浓度及注入速度等参数进行优化,在聚驱基础上可提高采收率10%左右.现场试验表明,注聚中后期进行气聚交替注入,油井含水率大幅度下降,二次受效明显,表明该项技术是提高聚驱效果的有效方法.在气聚交替过程中,利用天然气代替聚合物,可以节省聚合物,提高经济效益.

In order to improve the polymer flooding and thus enhance oil recovery from intermediate and low permeability oil layers,we conducted a study on gas/polymer alternate injection.By laboratory experiments,parameters for gas/polymer alternate injection were optimized,including gas-liquid ratio,combination of slugs,relative molecular weight of polymer,mass concentration of polymer solution and injection rate.Experimental result shows that gas/polymer alternate injection can increase oil recovery by more than 10% over pure polymer flooding.Field pilot test was implemented,which shows that by applying gas/polymer alternate injection at the middle stage of polymer flooding,water cut of oil wells can be decreased significantly and secondary effect is obvious.This study proves that gas/polymer alternate injection is an effective method to improve polymer flooding.Because gas is used to replace certain amount of polymer,this technique can save polymer and achieve much better economical benefit.