▎ 摘　　要

NOVELTY - A nano-micro-emulsion plugging agent is prepared by dispersing graphene powder in tetrahydrofuran, introducing nitrogen blowing, adding triethylamine and KH-570, heating and stirring, adding hydrazine hydrate, heating and continuously stirring, orderly washing with ethanol, water and tetrahydrofuran and drying to obtain first powder; dispersing in tetrahydrofuran, adding sulfonic betaine methacrylate, blowing nitrogen, adding azobisisobutyronitrile (AIBN), heating, reacting under nitrogen atmospher, steaming to remove solvent and vacuum drying to obtain modified graphene; crushing and sieving bentonite, adding sodium dodecyl benzene sulfonate, polyglycerol and bentonite powder after crushing into asphalt, quickly stirring and uniformly mixing and forming second powder by spray granulation; and dispersing in deionized water to prepare water dispersion, adding hydroxyethyl cellulose, uniformly stirring, adding modified graphene and chitosan nano gel, and fast stirring. USE - The method is used for preparing nano-micro-emulsion plugging agent for drilling fluid. ADVANTAGE - The method can neutralize negative charge of surface of clay by rich cation and firmly absorb to surface of clay, improves salt resistance of plugging agent by sulfonic acid group, uses graphene and bentonite as rigid material so that drilling liquid has good blocking performance, increases flexibility of graphene by grafting amphoteric ion polymer chain on graphene surface, forms stable composite material between bentonite layered structure by polymer chain intercalation, and blocks fine pores by chitosan nano-micro-gel structure. DETAILED DESCRIPTION - A nano-micro-emulsion plugging agent is prepared by: dispersing graphene powder in tetrahydrofuran to prepare 1% dispersion liquid, introducing nitrogen blowing for 30 minutes, adding triethylamine and KH-570, heating to 60degrees Celsius and stirring for 24 hours, adding hydrazine hydrate, heating to 90degrees Celsius and continuously stirring for 24 hours, orderly washing with ethanol, water and tetrahydrofuran and drying to obtain first powder; dispersing first powder in tetrahydrofuran, adding sulfonic betaine methacrylate, blowing nitrogen for 30 minutes, adding azobisisobutyronitrile (AIBN), heating to 60degrees Celsius, reacting under nitrogen atmosphere for 3-5 hours, steaming to remove solvent and vacuum drying to obtain modified graphene; crushing and sieving bentonite, adding sodium dodecyl benzene sulfonate, polyglycerol and bentonite powder after crushing into asphalt, quickly stirring and uniformly mixing and forming second powder by spray granulation; dispersing second powder in deionized water to prepare 10 wt.% water dispersion, adding 5 wt.% hydroxyethyl cellulose, uniformly stirring, adding modified graphene and chitosan nano gel, and fast stirring for 2 hours to obtain aqueous phase dispersion; and adding Tween 80 (RTM: polyoxyethylene (20) sorbitan monooleate), Span 80 (RTM: sorbitan monooleate) and liquid paraffin according to mass ratio of 1:2:3 into beaker and heating to 60degrees Celsius, stirring to uniformly mix to obtain oil phase, heating to 30degrees Celsius, introducing nitrogen for 30 minutes, stirring and slowly dropping aqueous phase dispersion, and continuously stirring for 30 minutes.