非离子表面活性剂分子结构对CO₂驱混相压力的影响

Effect of the Structure of Nonionic Surfactant on the Miscibility Pressure of CO₂ Flooding

王 芳 罗 辉 范维玉 梁 明 钱成多 南国枝

WANG Fang， LUO Hui， FAN Weiyu， LIANG Ming， QIAN Chengduo， NAN Guozhi

为揭示非离子表面活性剂对油/CO2界面张力和最小混相压力（MMP）的影响， 利用高温高压界面流变仪，采用下悬滴法， 研究了温度和非离子表活性剂分子结构对超临界 CO2/油界面张力和 MMP的影响规律。结果表明， 随着温度的升高， 超临界CO2/油界面张力和MMP逐渐增大，月桂醇聚氧丙烯醚 （C12PO6） 降低CO2驱混相压力的幅度先增大后减小， 60℃时的降幅最大 （25.6%）。直链脂肪醇碳数由12增至18时， 超临界CO2/油MMP逐渐增加， C12PO6降低CO2驱混相压力的效果最好。聚氧丙烯醚基团 （亲CO2端） 降低界面张力和CO2驱混相压力的效果好于聚氧乙烯醚基团。随聚氧丙烯醚聚合度增加， 超临界 CO2/油 MMP先降低后增加， 聚合度为 6时的 MMP最小 （13.22 MPa）。降低CO2驱混相压力效果最好的表面活性剂分子结构为碳十二醇聚氧丙烯醚-6 （C12PO6）。图5表1参19

In order to reveal the effect of nonionic surfactant on the interfacial tension between oil and CO2 and minimum miscibility pressure（MMP）， the influencing rule of temperature and molecular structure of nonionic surfactant on the interfacial tension between oil and supercritical CO2 and MMP was studied by pendant-drop method on autoclave. The results showed that the miscibility pressure of supercritical CO2 and oil and MMP increased gradually with increasing temperature. The decline of CO2 flooding miscibility pressure by lauryl alcohol polyoxypropylene allyl ether（C12PO6）increased first and then decreased， which showed the largest drop（25.6%）at 60℃. The MMP of supercritical CO2 and oil increased gradually when the carbon number of straight chain fatty alcohol increased from 12 to 18. C12PO6 reduced CO2 flooding miscibility pressure best. The interfacial tension and miscibility pressure of CO2 flooding were reduced sharper with polyoxypropylene ether group than polyoxyethlene ether group. The MMP decreased first and then increased with increasing polymerization degree of polyoxypropylene ether， which minimum was 13.22 MPa with 6 polymerization degree. C12PO6surfactant had best effect on decreasing miscibility pressure of CO2 flooding.

10.19346/j.cnki.1000-4092.2017.02.016