适合低渗透油藏的空气泡沫驱油技术研究及应用

Research and Application of Air Foam Flooding Technology for Low Permeability Reservoirs

低渗透油藏经过长时间注水开发后,含水率上升,驱油效果逐渐变差。因此,通过大量室内实验,优选出起泡性能较好的起泡剂BK-6以及稳泡效果较好的稳泡剂BK-51,进而研究出了一套适合低渗透油藏的空气泡沫驱油体系,其具体配方为:0.5%BK-6+0.05%BK-51。空气泡沫驱油体系具有良好的驱油效果,目标区块储层段岩心采取水驱油后继续空气泡沫驱的方式,可使采收率继续提高26.34%,最终驱油效率可以达到80.23%;而采取直接注泡沫驱油的方式,最终驱油效率可以达到87.53%,但直接注泡沫驱油时注入压力较大,给现场施工带来不便。因此,推荐目标油藏现场采取水驱油后再进行空气泡沫驱油试验。现场应用结果表明,延长油田A井组和B井组采取注空气泡沫驱油体系措施后,均取得了较好的控水增油效果,两井组累计增油均超过了300 m^(3),现场应用效果良好。

After a long time of water injection development, the water cut of the reservoir gradually increases and the oil permeability becomes poor. Therefore, through a large number of indoor experiments, a foaming agent BK-6 with better foaming performance and a stable foaming agent BK-51 was selected, and a set of air foam flooding system suitable for low permeability reservoirs was developed. The formula is 0.5%BK-6+0.05%BK-51. The air foam flooding system has good oil displacement effect. The way of air foam flooding after water flooding was adopted in the core block of the target block, the recovery factor was increased by 26.34% and the final displacement efficiency reached 80.23%. By adopting direct injection foam flooding, the final displacement efficiency reached 87.53%, but the injection pressure was large, which was inconvenience to field construction. Therefore, the target reservoir should be driven by water and then air foam flooding test. The field application results showed that the A well group and the B well group in Yanchang oilfield achieved good water control and oil increasing effects after adopting the measures of injecting air foam flooding system. The cumulative oil production in the two well group was over 300 m^(3), and the field application effect was good.