Preparation and Oil Displacement Performance Evaluation of Amphiphilic Janus Molybdenum Disulfide Nanosheets

Nanofluid flooding, as a new type of oil displacement technology in low permeability reservoirs, has attracted more and more attention due to its advantages of good injection, low reservoir damage, strong oil displacement ability, and intelligent response. Compared with spherical nanoparticles, Janus sheet nanomaterials have lower interfacial free energy and more limited rotation, can further prevent the diffusion of internal and external phase molecules, and form solid particle films with higher interfacial strength, showing excellent oil displacement performance. Janus nanosheets have a large specific surface area and abundant surface chemical groups, which have great application potential in enhancing oil recovery. Because of its sheet structure and unique physicochemical properties, molybdenum disulfide (MoS2) has attracted wide attention in enhancing oil recovery, but there is relatively little research on the Janus modification of MoS2 nanosheets. In this article, amphiphilic Janus molybdenum disulfide nanosheets (JSMS) were prepared by a one-pot method, and their microstructure and physicochemical properties were characterized and analyzed. Finally, through a core flooding experiment and microscopic displacement test, the ability and mechanism of JSMS nanofluids to enhance oil recovery were evaluated. The results showed that the JSMS had excellent interface properties because of its Janus structure. It can produce a strong, elastic interfacial film. At the same time, the JSMS nanofluid can realize wetting reversal of rock surfaces. The results of the core flooding experiments showed that JSMS had a good oil displacement effect. The JSMS nanofluid enhanced oil recovery effectively by 4.7% with low concentration (0.005 wt %). This work demonstrated the feasibility of the Janus MoS2 for enhanced oil recovery.