▎ 摘　　要

NOVELTY - Nano-filtration and oil displacement agent, comprises modified nano graphene oxide, modified nano silicon dioxide, surfactant, dissolving agent and cosolvent in which modified nano graphene oxide is aminated modified nano graphene oxide, modified nano silicon dioxide is nano silicon dioxide modified by coupling agent, surfactant is a mixture of polyethylene glycol and sorbitan polyoxyethylene monopalmitate or sorbitan monopalmitate, dissolving agent is d-limonene and/or ethyl lactate and cosolvent is methanol, ethanol, isopropanol and/or glycol. USE - The nano-filtration and oil displacement agent is useful in the technical field of petroleum exploitation. ADVANTAGE - The nano-filtration and oil displacement agent improves wettability of the reservoir, reduces interfacial tension and capillary force, improves recovery rate, avoids aggregation and flocculation of nanoparticles in solution and improves the efficiency. DETAILED DESCRIPTION - An INDEPENDENT CLAIM is also included for preparing nano-filtration and oil displacement agent, comprising (i) adding nano graphene oxide powder to proper amount of N-methyl pyrrolidone (NMP) to fully dissolve, then adding proper amount of 4, 4'-diamino diphenyl ether (ODA) under the atmosphere of nitrogen, stirring, dispersing, filtering, cleaning and drying to obtain amino-modified nano graphene oxide, (ii) adding silicon dioxide powder into toluene solution, stirring to make the nano-silicon dioxide fully disperse, adding mercaptopropyl trimethoxy silane into toluene solution dispersed with nano-silicon dioxide for reaction under heating condition, purifying and drying to obtain modified nano-silicon dioxide, (iii) adding modified nano graphene oxide and nano silicon dioxide into cosolvent, stirring and ultrasonically dispersing, then adding surfactant, heating to 35-40 ℃ for 45-60 minutes and (iv) adding the mixed solution of d-limonene and ethyl lactate into step (iii) heating to 50-55 ℃, stirring and mixing uniformly to obtain final product.