超低界面张力型与乳化型复合体系驱替稠油特征对比

Comparative Study between Ultra-low Interfacial Tension and Emulsification Oriented Compound Systems on Recovering Heavy Oil

刘义刚 丁名臣 韩玉贵 王业飞 苑玉静 陈五花

LIU Yigang DING Mingchen HAN Yugui WANG Yefei YUAN Yujing CHENWuhua

为了明确超低界面张力（IFT）和乳化机理对稠油复合驱提高采收率的影响，研究了两种分别以超低IFT 和 良好乳化性为导向的复合体系的IFT、乳化性能、泡沫性能和驱油性能。结果表明，超低IFT 型复合体系可将油 水IFT 降至2.6×10-4mN/m，但其形成乳状液的稳定性、体系起泡性和泡沫稳定性均较乳化型复合体系差，而后者 仅可将油水IFT 降至0.25 mN/m。尽管超低IFT 型与乳化型复合体系性能相差较大，复合驱过程中，由于体系扩 大波及体积能力相对较弱，两种体系提高采收率增幅相差较小。超低IFT 型泡沫驱采收率增幅可达38.3%，显著 高于乳化型泡沫驱的28.9%。在泡沫辅助下，超低IFT 洗油机理比乳化降黏机理更为关键。超低IFT 型泡沫驱驱 替稠油的采收率增幅大于大段塞复合驱，前者0.3 PV化学剂用量下的增幅达38.3%，后者0.5 PV化学剂用量下的 增幅仅为30.7%。超低IFT 型泡沫驱是目前提高稠油采收率较好的方式，单一复合体系驱替稠油存在化学药剂 的潜在浪费。图7表1 参15

In order to clarify the relative importance of ultra-low interfacial tension（IFT）and emulsification mechanisms for recovering heavy oil by compound flooding，the IFT，emulsification，foam and oil displacement performances of two compound systems guided by ultra-low IFT and good emulsification were studied. The results showed that，for the ultra-low IFT system，the oil-water IFT could be reduced to 2.6×10-4 mN/m，but it performed poorer in foaming and stabilizing emulsion and foam than the emulsified compound system，while the oil-water IFT of the later was only 0.25 mN/m. Although the properties of those two systems differed greatly，the increased oil recovery by ultra-low IFT system was similar to that of emulsion system during the simple compound flooding，which might be caused by the poor sweep volume during flooding. However，that increased by ultra-low IFT foam was 38.3%，which was much higher than that of 28.9% by emulsion foam flooding. This indicated that the mechanism of oil washing by ultra-low IFT was more critical than that of viscosity reduction by oil-in-water emulsification during foam flooding. Ultra-low IFT foam flooding （water alternative gas injection） could improve heavy oil recovery more than increasing the slug of compound system. The recovery could be increased to 38.3% by 0.3 PV the former strategy，while 30.7% by 0.5 PV the latter. Ultra-low IFT foam flooding was the better way to improve heavy oil recovery at the present，and the displacement of heavy oil by single compound system might be a waste of chemical agents.