烷基苯孪连表面活性剂对固体表面润湿性的影响

Effects of Ethylene-Bis(Alkyl Benzene Sulfonate)Gemini Surfactant on Wettability of Solid Surfaces

研究了孪连表面活性剂DSDBS-2（乙撑双十二烷基苯磺酸钠）的吸附、润湿及驱油性能。以芘为探针,用稳态荧光法测定能反映DSDBS-2在高岭土表面吸附层微极性的I3和I1值,求得DSDBS-2在溶液浓度为10 mg/L时开始在高岭土表面形成聚集体,溶液浓度为40-100 mg/L时聚集体逐渐完善,溶液浓度高于100 mg/L时形成新的聚集体。在亲水高岭土粉体表面的接触角,随溶液浓度增加先减小,在16.5 mg/L处达到最低值后由于新聚集体形成而趋于增大。由表面张力-溶液浓度曲线求得DSDBS-2的临界胶束浓度为10 mg/L。DSDBS-2可使亲水的玻片、石英片表面强亲水,接触角降至12°以下,使亲油的玻片表面变亲水,接触角降至80°以下。驱油实验温度40℃,使用长29 cm、水测渗透率0.35-0.54μm2的人造砂岩岩心,黏度15.8 mPa.s的克拉玛依七区井口脱气脱气原油,用注入水配制的DSDBS-2（40 mg/L）/HPAM（1500 mg/L）表聚二元驱油剂,该驱油剂黏度49.4 mPa.s,与原油间界面张力0.106 mN/m;水驱之后注入0.5 PV驱油剂,采收率增值分别为15.22%和16.78%（亲油岩心）,19.82%和20.13%（亲水岩心）。表聚二元驱中岩石表面润湿性的改变应予重视。

The interfacial tension,IFT,with Zhuangxi＇s water free heavy crude oil and the oil displacement efficiency at 55℃ were investigated for anionic-nonionic surfactant 9AS-5-0,sodium nonylphenylpolyoxypoly oxy propylene（5）sulfate.The heavy crude oil was taken from well Zhuang-106-15-X18,containing 20.54% resin-asphatene and having at 55℃ density of 0.9302 g/cm3 and viscosity 238 mPa·s.For a series of 2 g/L 9AS-5-0 aqueous solution of varying NaCl concentration,the dynamic IFT with the crude oil decreased with increasing NaCl concentration from 0 to 80 g/L and increased with further increasing NaCl concentration from 80 to 120 g/L,changed rather slowly with time and did not reach ultralow values;ultralow values of dynamic IFT were created quickly at NaCl concentration 80 g/L;the steady values of IFT observed in 60 min for 2 g/L 9AS-5-0 solution of NaCl concentration 1,60,and 80 g/L were of 0.3050,0.0262,and 0.0014 mN/m,respectively.On epoxy cemented quartz reservoir models of permeability 3.0～4.0 μm2 with heavy crude oil saturated,injecting 0.5 PV of 2 g/L 9AS-5-0 solution with NaCl concentration 1,60,and 80 g/L resulted in an extremal oil recovery of 38.99%,38.30%,and 36.81%,respectively,which indicated a lower oil recovery for a higher IFT surfactant solution,It was considered from the relationships of oil recovery and injecting pressure vz volume injected that the oil recovery was enhanced by this surfactant flooding solution by the way of enlargement of sweeping volume.