两性-阴离子表面活性剂体系的构建及其防水锁效果

Anti-water Blocking Effect Using the Developed Amphoteric-anionic Surfactant System

李小平 黄维安 李 轩 裴 成 张荣辉 王曾定 赵福豪

LI Xiaoping HUANG Wei’an LI Xuan PEI Cheng ZHANG Ronghui WANG Zengding ZHAO Fuhao

针对低渗储层水锁损害问题，提出使用表面活性剂改变储层润湿性进而达到防水锁效果的方法。考察了阴离子表面活性剂（SDAS-1、SDAS-2）和两性表面活性剂（SDAS-3、SDAS-4）及其复合体系降低表面张力、改变储层润湿性和减小毛细管力的能力，并研究了最优复合体系的防水锁性能。研究结果表明，表面活性剂单剂均可减缓砂岩储层表面的强亲水性；复合体系优于单剂，拟黏附功降低作用明显，表现出协同增效作用。通过优化浓度和配比，构建的SDAS-3/SDAS-1体系在低浓度下即可将表面张力降低至24.37 mN/m，使石英亲水表面向中性润湿转变，拟黏附功低至11.22。最优体系配比为1∶1，各组分浓度为1×10-4mol/L，相比于标准盐水，岩心对表面活性剂溶液24 h的自吸量由2.58 g降低至0.85 g，渗透率损害率由73.40%降低至21.40%，油相通过砂管的时间降低了50%，表明所构建体系有良好的防水锁效果。

Aiming at the problem of the water-blocking damage in low permeability reservoirs，the method of using surfactant to change the wettability of the reservoir was proposed to achieve anti-water blocking effect in this paper. The effects of reducing the surface tension and changing the wettability of the reservoir by anionic（SDAS-1、SDAS-2）and amphoteric（SDAS-3、SDAS-4）surfactants and their complex system were investigated. The results showed the two surfactants could retard the strong water-wet surface of sandstone reservoirs；moreover，the complex system was better than single agent，and the reduction of quasi-adhesion work was obvious，showing synergistic effect. By optimizing the concentration and ratio，the constructed SDAS-3/SDAS-1 complex system could reduce the surface tension to 24.37 mN/m at low concentration，the quasi-adhesion work to 11.22，which made the hydrophilic surface of quartz transition to neutral wetting. The optimum ratio of complex system was 1∶1，the concentration of each component was 1×10-4 mol/L. It was found that the self-priming amount of the core to the optimized complex system was reduced to 0.85 g/24 h compared with 2.85 g/24 h of standard brine，and the permeability damage rate of was reduced to 21.4% compared with 73.4% of the standard brine，the time of the oil phase passing through the sand tube was 50% lower than that of the standard brine，which showed that the constructed complex system had a good anti-water blocking effect.

10.19346/j.cnki.1000-4092.2020.01.013