Study on interface regulation effects of Janus nanofluid for enhanced oil recovery

In this paper, Janus silica nanoparticles (JNS) were fabricated through a facile in-situ modification way. The hydrophilic-hydrophobic balance of Janus silica was regulable by changing the grafting amount of alkyl chains. In contrast to unmodified silica, Janus silica with amphiphilic features similar to surfactants had remarkable interface regulation effects at liquid-liquid and solid-liquid interfaces. JNS nanofluid lowered the interfacial tension and increased the interfacial modulus. It was also found that JNS had excellent emulsifying abilities. Moreover, JNS nanofluid could reverse the strongly oil-wet rock into water-wet, converting the capillary resistance into the driving force. The formation of disjoining pressure and reduced adhesion work of JNS nanofluid facilitated oil film stripping. The core flooding result showed that JNS nanofluid effectively enhanced oil recovery by 15.9 % with low dosages. The finding of this paper would help further understand the interface regulation effects of Janus nanofluid and construct an efficient nanofluid flooding system for enhanced oil recovery.