Multiscale study of Janus nanosheets' interfacial activity

As the challenge of enhancing oil recovery from reservoirs continues to grow, it becomes increasingly crucial to seek out new materials for oil displacement. Janus graphene oxide (JGO) with excellent interfacial activity stands out as a promising candidate, which enables it to locate crude oil and effectively displace it towards production wells. One key advantage of JGO is its ability to reduce interfacial tension and create interfacial films, attributed to JGO nanosheets adsorbing at oil-water interfaces. Another noteworthy property of JGO is its capacity to transform oil-wet rock surfaces into water-wet surfaces, which is because JGO nanosheets can interact hydrophobically with crude oil molecules on rock surfaces. In addition, JGO helps mitigate capillary resistance by altering the concave oil-water front to a flat state. Microscopic displacement shows that JGO nanosheets enlarge the sweep efficiency and oil-washing efficiency of water. Nuclear magnetic resonance experiment indicates that JGO nanofluid can increase oil recovery by 17.1 %. This research presents a comprehensive exploration of the interfacial activity of Janus nanofluid, spanning from the molecular scale to the micro and core scales.