Nanofluids are stable mixtures of nanoscale particles dispersed in base fluids with good prospects in enhanced oil recovery in the petroleum industry. In this review, the mechanisms and evaluation methods of stable nanofluids were analyzed. The effects of nanoparticles on viscosity, electrical conductivity, and surface/interfacial tension of base fluids were discussed. The results of laboratory research and field tests revealed that nanofluids could improve the oil recovery through plugging and profile control, transformation of wettability of rock surface, changes in oil–water interface properties, and increases in the viscosity ratio between fluids. On the other hand, nanoparticles might stabilize oil–water emulsions produced during the extraction stage, adversely affecting subsequent oil–water separation processes, especially the electrical dehydration. However, careful analysis suggested lack of in-depth studies regarding the impacts of nanoparticles on droplet coalescence inside electro-dehydration plants. The present analyses will hopefully assist future investigations in nanofluidics.

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纳米流体的性质及其在提高采收率中的应用：综述

纳米流体是分散在基础流体中的纳米级颗粒的稳定混合物，在提高石油工业的采油率方面具有良好的前景。本文对稳定的纳米流体的机理和评价方法进行了分析。讨论了纳米颗粒对基础流体的粘度，电导率和表面/界面张力的影响。实验室研究和现场测试的结果表明，纳米流体可以通过堵塞和剖面控制，改变岩石表面的润湿性，改变油水界面特性以及增加流体之间的粘度比来提高采油率。另一方面，纳米颗粒可能会稳定萃取阶段产生的油水乳状液，从而对后续的油水分离过程产生不利影响，特别是电脱水。然而，仔细的分析表明，缺乏关于纳米颗粒对电脱水设备内部液滴聚结的影响的深入研究。目前的分析将有望有助于纳米流体的未来研究。