二元复合体系乳化性能及其对普通稠油的驱替效果

Emulsification properties of binary composite system and their effect on displacement of conventional heavy oil

为确定非超低油水界面张力(10^-1mN/m数量级)、乳液稳定性及乳化降黏能力良好的1#二元复合体系驱替普通稠油的效果,分别从界面张力、乳化难易程度、乳液稳定性、乳化降黏能力和驱油效果5个方面进行评价,同时与超低界面张力型2#和3#二元复合体系(10^-3mN/m数量级)进行对比。结果表明,1#二元复合体系虽较难乳化稠油,但其形成的乳液稳定性更强,说明乳液稳定性与超低界面张力无相关性。渗流实验结果表明:1#二元复合体系能够显著降低稠油流动阻力,而2#和3#二元复合体系无此效果;分析1#,2#和3#二元复合体系乳化性能的差异,认为乳液稳定性是二元复合体系乳化改善稠油流动性的关键。驱油实验结果表明,1#二元复合体系可提高采收率15.6%,明显高于超低界面张力型2#和3#二元复合体系的采收率增幅(均在10.0%左右),说明乳液稳定性和乳化降黏能力在二元复合体系驱替普通稠油中具有重要作用。

Binary composite system 1# has a non-ultralow oil-water interfacial tension(10^-1 mN/m level),good emulsion stability,and strong viscosity reduction capacity by emulsification. In order to investigate the displacement efficiency of this system on conventional heavy oil,evaluations are carried out on five aspects including:interfacial tension,degree of emulsification difficulty,emulsion stability,viscosity reduction capacity by emulsification,and displacement efficiency. The results are compared with binary composite systems 2# and 3# with ultra-low interfacial tension(10^-3 mN/m level)as well. The results show that the emulsion formed by 1# is more stable,indicating that there is no correlation between emulsion stability and ultra-low interfacial tension,though 1# is more difficult to emulsify heavy oil than 2# and 3#. Percolation experiment results show that 1# could significantly decrease the flowing resistance of heavy oil,while 2# and 3# have no similar effect. According to the emulsifying difference of systems 1#,2# and 3#,it is believed that the emulsion stability is the key to improve the flow of heavy oil through emulsification. The oil displacement test result show that composite system 1# could increase oil recovery by 15.6%,which is much higher than that of 2# and 3# with ultra-low interfacial tension(about 10.0%). This indicates that emulsion stability and viscosity reduction capacity by emulsification are important to the displacement of conventional heavy oil in binary composite system.