石油羧酸盐/重烷基苯磺酸盐/碱复配体系的界面活性及吸附特性

Interfacial Activity for and Adsorption of Surfactants from Petroleum Carboxylates/Heavy Alkyl Benzene Sulfonates/Alkaline Combinational Systems

实验考察了石油羧酸盐(POS 2和POS 4)/重烷基苯磺酸盐(ORS 41)/碱(NaOH)复配体系与大庆脱气原油(45℃粘度18 7mPa·s)间的界面张力IFT(45℃)及2种表面活性剂在大庆去油油砂上的吸附特性。实验复配体系用矿化度4 3g/L的模拟注入水配制。在复配体系中加入C2～C5正构脂肪醇使实验油水体系IFT达到平衡的时间由～70min缩短至～50min,使IFT稳定值(～5 8×10-3mN/m)有所降低,各种醇的影响力相差不大,C3醇略好。当POS 2、ORS 41、C2、C3混合醇(1∶1)质量比为24∶8∶1时,在POS 2浓度0 6～6 0g/L、NaOH浓度2 5～12g/L范围出现超低IFT。POS 4/CTMAB或CPC/NaOH复配体系只在很窄的阳离子表面活性剂浓度范围出现超低IFT。OP类和Tween类非离子表面活性剂使POS 2/NaOH体系的IFT升高,升高幅度随加入量和乙氧基数增大而增大。POS 4和ORS 41在油砂上的吸附符合Langmuir定律,从POS 4/ORS 41/NaOH(2 5/0 83/12g/L)复配体系中的吸附量(饱和吸附量为1 444和6 741mg/g油砂),低于从POS 4/NaOH(2 5/12g/L)和ORS 41/NaOH(0 83/12g/L)体系中的相应吸附量(分别为2 925和7 581mg/g油砂)。图6表1参9。

The interfacial tension, IFT, at 45℃ between petroleum carboxylates (oxidized petroleum soaps), POS-2 or POS-4/heavy alkyl benzene sulfonates, ORS-41/alkaline NaOH aqueous solutions and a degased Daqing crude oil (with viscosity 18.7 mPa·s at 45℃) and the adsorption of the two surfactants on deoiled Daqing reservoir sand at 20℃ are experimentally investigated. The experimental solutions are prepared in a simulation injection water of TSD=4.3 g/L. For an O/W system with normal C_2-C_5 aliphatic alcohols introduced into the aqueous solution, the time needed for IFT to reach its equilibrium value is shortened from ～70 min to ～50 min and the stable IFT value is decreased in some extent from the initial value of ～5.8×10^(-3) mN/m; the influencing power of these alcohols is similar with C_3 alcohol being more effective. When the mass ratio of POS-2, ORS-41, and mixed C_2+C_3 alcohols (1∶1) is of 24∶8∶1, ultralow IFT values appear at concentration of POS-2 in range 0.6-6.0 g/L and of NaOH in range 2.5-12 g/L. For POS-4/CTMAB or CPC/NaOH solutions, ultralow IFT values appear only at concentration of the cationic surfactant in a very narrow range. With nonionic surfactants of OP and Tween series added, the IFT value of POS-2/NaOH solution increases in higher extent when dosage and EO number are larger. The adsorption isotherm of POS-4 and ORS-41 on the reservoir sand fits to the law of Langmuir and the amount of adsorption of POS-4 and ORS-41 from POS-4/ORS-41/NaOH (2.5/0.83/12 g/L) solution is lower than that from POS-4/NaOH (2.5/12 g/L) and ORS-41/NaOH(0.83/12 g/L) solutions: the saturation adsorption from the tricomponent S/S/A and the dicomponent S/A solutions of POS-4 is of 1.444 and 2.925 mg/g sand and of ORS-41-6.741 and 7.581 mg/g sand, respectively.