纳米SiO2/SDS分散体系的稳定性及界面活性*

Stability and Surface Activity of Nano-SiO2/SDS Dispersion Systems

王伟琳 陈五花 丁名臣 王业飞

WANG Weilin CHEN Wuhua DING Mingchen WANG Yefei

纳米颗粒/表面活性剂 分散体系的稳定性是一个不容忽视的问题，为了使其在油田得到实际应用，应对分 散体系的稳定性及界面活性进行研究。通过沉降实验、浊度及Zeta电位测定研究了离子组成、SiO2的含量和pH 值与纳米SiO2/十二烷基硫酸钠（SDS）体系稳定性的关系，并研究了上述条件下纳米SiO2对SDS降低油水界面张 力的影响。研究结果表明，在NaCl盐水中，体系稳定性较好，纳米SiO2的加入有助于SDS降低界面张力。模拟 地层水中，纳米SiO2含量的增加，二价Ca2+，Mg2+ 离子的存在，均使体系稳定性变差。SDS降低界面张力的能力随 着SiO2含量的增加先增后减，界面张力在0.5%时达到最低。在酸性介质中，颗粒间水化作用的增强及SiO2颗粒 周围H+ 保护层的存在使模拟地层水中体系稳定性得到明显改善。在SiO2质量分数大于0.5%时，更低的pH有利 于提高体系降低界面张力的能力。图7表1参21

The stability as well as the interfacial activity of nanoparticle/surfactant dispersion system should be analyzed for its application in enhanced oil recovery processes. The influence of ion composition，nano-SiO2 content and pH value on the stability of nano-SiO2/SDS systems were analyzed by sedimentation，nephelometry and Zeta potential measurements. The effects of nano-SiO2 on the capability of SDS to reduce interfacial tension were also studied under the same conditions. The experimental results suggested that in NaCl brine，the nano-SiO2/SDS systems had good stability，and the addition of nano-SiO2 could enhance the ability of SDS to reduce interfacial tension. In simulated formation water，the increase of nano-SiO2 content and the presence of divalent Ca2+ and Mg2+ ions tended to destabilize the system，the ability of SDS to reduce interfacial tension first increased and then decreased with the increase of nano-SiO2 content，the interfacial tension reached a minimum at 0.5% nano-SiO2. In acidic medium， the enhanced intergranular hydration force and the presence of H+ protective layer around nano-SiO2 could improve the stability of the system in the formation water. And when the mass fraction of nano-SiO2 was more than 0.5%，the lower pH value was beneficial to improve the ability of the system to reduce the interfacial tension.

10.19346/j.cnki.1000-4092.2020.03.014