低渗透油藏水驱转空气泡沫驱提高采收率物理模拟实验

为进一步提高镇泾油田低渗透油藏原油采收率,利用室内驱油物理模拟技术,开展了水驱转空气泡沫驱提高采收率实验研究,探讨了空气泡沫驱对低渗透油藏水驱开发效果的影响。实验结果表明,在模拟地层条件下,初始水驱阶段的平均采收率为29.06%,水驱转空气泡沫驱后,采收率得到明显提高,增量均在10%以上;再次水驱后,最终采收率平均可达到45.42%。随着空气泡沫注入速度的增加,采收率呈上升趋势,但增幅逐渐减小。注入速度越大,气体突破时间越早,不过实验过程中并未发生明显的因气窜而导致采收率降低的现象;在相同条件下,空气泡沫注入总量为1倍孔隙体积时的采收率比0.6倍孔隙体积时的高5%。研究认为,通过交替注入起泡剂溶液与空气实现空气泡沫驱对于注水开发的低渗透油藏进一步提高原油采收率是可行的。

Physical modeling study of air foam flooding EOR technology for low permeability reservoirs based on water flooding

In order to further enhance oil recovery in Zhenjing low permeability reservoirs, the air foam flooding EOR technology was researched through core displacement experiments. The experimental results suggested that air foam flooding after water flooding could improve oil displacement efficiency in low permeability reservoirs. Meanwhile, the development effect of following water flooding could be enhanced. The displacement efficiency for initial water flooding was 29.06%, and the following air foam flooding improved it for more than 10 percentage points. After water flooding again, the oil displacement efficiency could reach 45.42% for the average. The results also indicated that increasing injection rate or injection volume of air foam could improve the ultimate oil displacement efficiency with a shortened time of gas breakthrough, and gas channeling had little effect on oil recovery. Air foam flooding EOR technology using alternative injection of foaming agent solution and air was technically feasible for low permeability reservoirs based on water flooding.