脂肪醇聚氧乙烯醚磺酸盐系列表面活性剂的协同效应

Synergism of Aliphatic Alcohol Polyoxyethylene Ethers Sulfonate Surfactant Series

为满足高温、高盐油藏三次采油的需求,采用自制的脂肪醇聚氧乙烯醚磺酸盐(NNA)系列作为抗温、耐盐驱油表面活性剂,考察了脂肪醇聚氧乙烯醚磺酸盐系列表面活性剂复配前后原油-矿化水体系界面张力的变化,并讨论了其协同效应,并采用静态吸附实验考察了该系列表面活性剂的吸附性能。结果表明,随着NNA表面活性剂分子中氧乙烯链节数的增加,原油-矿化水体系的油-水界面张力最低值对应的矿化度向着高矿化度方向移动,当氧乙烯链节数适中时,可以获得超低油-水界面张力。同系列表面活性剂复配可以显著改善表面活性剂体系的界面活性,具有明显的协同作用。复配表面活性剂使油-水界面张力达到平衡值的时间大大缩短,拓宽了达到超低界面张力的表面活性剂质量分数范围(0.03%～0.15%),耐盐性能也得到提高,使用单剂时耐盐能力在100g/L以下,复配后耐盐能力达到100g/L以上。同系列表面活性剂在油砂上的吸附规律相同,从而降低了表面活性剂被地层色谱分离的可能。

In order to meet the needs of enhanced oil recovery（EOR） for high-temperature and high-salinity reservoir,a series of aliphatic alcohol polyoxyethylene ethers sulfonate surfactants（NNA） with thermal stability and salt tolerance prepared in laboratory was used as oil displacement agent of EOR.The changes of interfacial tension of crude oil-mineralized water before and after the combination of surfactant series were investigated and the synergism between surfactants was discussed.The adsorption properties of the surfactants were studied by static adsorption experiment.The results showed that the salinity at the minimum value of oil-water interfacial tension moved towards high salinity direction with the increase of oxyethylene（EO） chain link number in surfactant molecule and the oil-water interfacial tension（IFT） could reach its ultra-low value（10-3mN/m）with moderate oxyethylene chain link number.The combination of surfactant series had obviously synergism,meaning that combination of surfactant series shortened the time achieving IFT equilibrium value,enlarged the mass fraction range of surfactant forming ultra-low IFT（0.03%-0.15%） and enhanced salt resistance of surfactant.The salt tolerance of surfactant series was below 100 g/L when only one surfactant was used and above 100 g/L after combination of two surfactants.The adsorption isotherms of surfactant series had similar change tendency,reducing the possibility of chromatographic separation of surfactant components in reservoir.