碱-表面活性剂乳化稠油降黏影响因素研究

Study on the influencing factors of viscosity reduction of heavy oil emulsified by alkali-surfactant

在鲁克沁油藏地层温度80℃下,研究了不同浓度的表面活性剂溶液、碱-表面活性剂溶液以及剪切时间对鲁克沁稠油乳状液黏度的改善效果。碱能与稠油中的有机酸发生化学反应产生表面活性物质,表面活性剂能降低油水界面张力,破坏胶质沥青质分子间的氢键,二者具有协同作用。实验测量了在稠油中添加不同浓度表面活性剂、碱、碱-表面活性剂后形成的乳状液黏度,分析碱和表面活性剂对稠油乳化降黏的影响。实验结果表明,碱-表面活性剂二元复合体系比单一表面活性剂的乳化降黏效果更好,剪切时间越长稠油乳状液黏度越低,最终稠油乳状液黏度趋于稳定。经过40 min剪切后,加入浓度为1 000 mg/L的表面活性剂+浓度为300 mg/L的Na2CO3的稠油乳状液黏度降为44 mPa·s,降黏率达到了85%。碱-表面活性剂对鲁克沁稠油乳状液降黏有很好的改善作用,对指导鲁克沁稠油的现场开发具有一定的理论意义和实际应用价值。

At the formation temperature of Lukeqin reservoir at 80 °C, this article studied the effects of surfactant solution with different concentrations, alkali-surfactant solution with different concentrations and shear time on the viscosity of Lukeqin heavy oil emulsion. Alkali can neutralize organic acids in heavy oil and react to generate some surfactant to reduce the interfacial tension between oil and water. And it destroy the hydrogen bond between the gelatinous asphaltene molecules. So that alkali and surfactant have a synergistic effect. Measured the viscosity of emulsion formed by adding different concentrations of surfactant, alkali and alkali-surfactant to heavy oil. Analyzed the influence of alkali and surfactant on viscosity reduction of heavy oil emulsification. The experimental results show that the emulsification viscosity reduction effect of alkali-surfactant binary composite system is better than that of single surfactant. The longer the shear time is, the lower the viscosity of heavy oil emulsion is, and finally the viscosity of heavy oil emulsion tends to be stable. After 40 min shearing,the viscosity of heavy oil emulsion with 1 000 mg/L surfactant and 300 mg/L Na2CO3is 44 mPa·s. The viscosity reduction rate reached 85%. Alkali-surfactant has a good effect on the viscosity reduction of Lukeqin heavy oil emulsion, which has certain theoretical significance and practical application value for guiding the field development of Lukeqin heavy oil.