APEC(Na)降低油水界面张力影响因素研究

Influencing Factors of APEC(Na) on Reducing Interfacial Tension

潘斌林

PAN Bin-Lin

在埕岛油田埕北油水条件下，考察了烷基酚聚氧乙烯醚羧酸钠(APEC(Na)) 阴非离子表面活性剂乙氧基（EO）数、温度、无机盐、溶液pH值对油水界面张力的影响。结果表明，APEC(Na)中的EO数为6时的油水界面张力最低6.5×10-3 mN/m。温度由30℃增至80℃，0.3%的APEC(Na) （EO数=6）海水溶液与埕北原油间的界面张力由5.6×10-2 mN/m降至6.4×10-3 mN/m；在APEC(Na)完全溶解后，温度（50~80℃）对界面张力的影响不明显。单一NaCl、Na2SO4、NaHCO3、CaCl2、MgCl2无机盐对APEC(Na)降低油水界面张力产生影响。随无机盐浓度升高，界面张力均先降低后升高；阳离子类型对界面张力的影响强于阴离子类型。Na2SO4、MgCl2、CaCl2加量分别为25×104、10×104、25×104 mg/L时，界面张力最低，分别为1.2×10-3、2.2×10-3、5.8×10-3mN/m，Mg2+对APEC(Na)界面活性的影响最大。在APEC(Na)海水溶液中加入1% NaOH，EO数为7的APEC(Na)可使原油界面张力达到最低值2.9×10-3 mN/m；随EO数为7的APEC(Na)海水溶液pH值升高，油水界面张力先降低后升高，pH值为13.4（NaOH加量1%）时的界面张力最低。

The effect of ethylene oxide chain length (EO number), temperature, inorganic salts and pH value on sodium alkyl phenol polyoxyethylene ether carboxylate (APEC(Na)) reducing interfacial tension (IFT) was researched under Chengbei reservoir conditions. The results showed that when the EO number was 6, the IFT between crude oil and surfactant solution of sea water could achieve the lowest value 6.5×10-3 mN/m. When the temperature rose from 30℃ to 80℃, the IFT between sea water contained 0.3% APEC(Na) (EO=6) and crude oil reduced from 5.6×10-2 mN/m to 6.4×10-3 mN/m. While after the surfactant completely dissolved between 50℃ to 80℃, the temperature had no influence to IFT. When there was one kind of inorganic salt in solution, the IFT decreased first and then increased with increasing concentration of inorganic salt. The effect of cation on IFT was stronger than that of anion. When the mass concentration of Na2SO4, MgCl2 and CaCl2 was 25×104,10×104 and 25×104 mg/L, the minimum IFT of oil-water was 1.2×10-3, 2.2×10-3 and 5.8×10-3 mN/m, respectively. In inorganic ions, Mg2+ had more obvious influence to APEC(Na) than others. Adding 1% NaOH to APEC(Na) solution of sea water, the APEC(Na) with 7 EO number could reduce the IFT to the lowest value 2.9×10-3 mN/m. The IFT between APEC(Na) (EO=7) solution and crude oil decreased first and then increased with increasing pH value of sea water. When the pH value was 13.4 (1% NaOH), the IFT reached the minimum value.