摘要
疏水纳米颗粒吸附在岩心孔壁发生去水湿,形成超强疏水层,是纳米颗粒吸附法降压增注技术的关键。采用热力学理论研究疏水球状纳米颗粒在亲水表面吸附后产生去水湿的临界覆盖率,利用实际储层参数讨论纳米颗粒吸附表面诱发去水湿的主要因素及影响规律,分析去水湿的力学机制;开展纳米颗粒吸附岩心表面的去水湿模拟实验,研究岩心表面润湿性的变化和纳米颗粒的覆盖率。结果表明:岩心表面发生去润湿现象要求纳米颗粒覆盖率大于临界覆盖率;增大颗粒接触角和基底接触角,减小纳米颗粒粒径,降低液气压差,都可以降低临界覆盖率,有利于产生去水湿;疏水纳米颗粒吸附在岩心表面,使表面接触角从30°增加到127°,颗粒覆盖率达到74%,大于临界覆盖率72%;去水湿现象确实可以通过疏水纳米颗粒吸附诱发产生,验证了理论分析的准确性。
The adsorbed hydrophobic nanoparticles on the core wall can form super hydrophobic layer due to the dewetting,which is the key to Nanofluid drag reduction technology. The critical coverage rate of hydrophobic spherical nanoparticles after adsorption on hydrophilic surfaces was investigated by thermodynamic theory. The main factors affecting the dewetting and their influences were discussed by using the actual reservoir parameters,and the mechanical mechanism of the dewetting was analyzed as well. The dewetting experiment of the core surface adsorbed by nanoparticles was carried out,and the wettability of the core surface and the coverage rate of nanoparticles were studied. The results show that the dewetting requires the coverage rate of nanoparticles is larger than the critical coverage rate. And increasing the particle contact angle and the contact angle of the substrate,or reducing the particle size or reducing the fluid-gas pressure difference can reduce the critical coverage rate,which is beneficial to the dewetting. After the hydrophobic nanoparticles adsorb on the core surface,the surface contact angle increases from 30° to 127°,the particle coverage rate reaches 74%,which is greater than the critical coverage rate of72%. The results indicate that the dewetting could be induced by the adsorption of hydrophobic nanoparticles,which verifies the accuracy of the theoretical analysis.
作者
顾春元
刘子昂
狄勤丰
张景楠
GU Chunyuan;LIU Ziang;DI Qinfeng;ZHANG Jingnan(Shanghai Institute of Applied Mathematics and Mechanics,Shang hai University,shanghai 200072,china;Shanghai Key Laboratory of Mechanics in Energy Engineering,Shang hai uiversity,shanghai 200072,china)
出处
《中国石油大学学报（自然科学版）》
EI
CAS
CSCD
北大核心
2018年第4期174-180,共7页
Journal of China University of Petroleum(Edition of Natural Science)
基金
国家自然科学基金项目(51274136)
上海市重点学科建设项目(S30106)
关键词
疏水纳米颗粒
吸附层
去水湿
临界覆盖率
减阻
hydrophobic nanopartices
adsorption layer
dewetting
critical coverage ratio
drag reduction
