▎ 摘　　要

NOVELTY - Polyaminosilane grafted graphene oxide plugging agent is claimed. The polyaminosilane grafted graphene oxide plugging agent is prepared by e.g. (i) stirring graphite, sodium nitrate, concentrated sulfuric acid, potassium permanganate, reacting, and ultrasonically processing, (ii) dispersing the obtained graphene oxide powder in absolute ethyl alcohol, ultrasonically stirring, stirring and reacting with ethanol solution of amino silane compound to obtain amino functionalized graphene oxide, (iii) dispersing the amino functionalized graphene oxide in methanol solution, stirring with diene compound, and washing by absolute ethyl alcohol to obtain the product a, and (iv) dispersing the product a in methanol, ultrasonically stirring, stirring and reacting with amine compound methanol solution under condition of nitrogen atmosphere and ice water bath for 12-48 hours, washing by anhydrous ethanol, centrifuging, and vacuum drying at 65℃ to obtain final product. USE - The polyaminosilane grafted graphene oxide plugging agent is useful for oil-based drilling fluid (claimed). ADVANTAGE - The polyaminosilane grafted graphene oxide plugging agent: has 50-1500 nm roughly distributed particle size, which can effectively seal the nano-pores and fractures in the shale formation, and thus it can effectively stabilize the well wall and prevent collapse; has little effect on the performance of the drilling fluid, which is beneficial to reducing the filtration loss of the drilling fluid; and ensures the oil-based drilling fluid has excellent performance in terms of rheological properties and plugging properties under shale formation conditions. DETAILED DESCRIPTION - Polyaminosilane grafted graphene oxide plugging agent is claimed. The polyaminosilane grafted graphene oxide plugging agent is prepared by (i) placing graphite, sodium nitrate and concentrated sulfuric acid having mass concentration of 98 % in a three-necked flask, slowly adding potassium permanganate, and stirring at 35℃ for 5-10 hours, adding the second part of potassium permanganate, stirring and reacting for 8-12 hours, removing the residual potassium permanganate using hydrogen peroxide solution, centrifuging, washing the product by distilled water, and ultrasonically processing to obtain graphene oxide dispersion, vacuum drying the graphene oxide dispersion at 65℃ to obtain graphene oxide powder, (ii) dispersing the graphene oxide powderin absolute ethyl alcohol and ultrasonically stirring for 30 minutes, slowly adding ethanol solution of amino silane compound, stirring and reacting for 8-12 hours at 35-55℃, stirring, precipitating the product by n-hexane, centrifuging, washing with acetone, and drying to obtain amino functionalized graphene oxide, (iii) dispersing the amino functionalized graphene oxide in methanol solution and placing in a three-mouth flask for ultrasonic stirring for 30 minutes, slowly dripping diene compound under the conditions of nitrogen atmosphere and ice-water bath, titrating, stirring at elevated temperature of 65-85℃ for 6-8 hours, washing by absolute ethyl alcohol, precipitating with n-hexane, and vacuum drying at 65℃ to obtain the product a, and (iv) dispersing the product a in methanol, ultrasonically stirring for 30-60 minutes, slowly adding amine compound methanol solution, stirring and reacting under the condition of nitrogen atmosphere and ice water bath for 12-48 hours, washing by anhydrous ethanol, centrifuging, and vacuum drying at 65℃ to obtain polyaminosilane grafted graphene oxide. In step (i), the mass ratio of graphite and sodium nitrate is 2:1-3:1, the ratio of graphite and concentrated sulfuric acid is 1 g:50-60 ml, the mass ratio of graphite and potassium permanganate is 1:2-1:4, the ratio of the graphite and hydrogen peroxide solution is 1 g:100-200 ml, the mass concentration of the hydrogen peroxide solution is 25-30 %. In step (ii), the ratio of the graphene oxide and absolute ethyl alcohol is 1 g:150-200 ml, the ratio of graphene oxide and amino silane compound ethanol solution is 1 g:50-100 ml, the volume ratio of aminosilane compound to ethanol in the ethanol solution aminosilane compound is 1:10-15. In step (iii), the ratio of the amino functionalized graphene oxide and methanol is 1 g:10-15 g, the ratio of amino functionalized graphene oxide and diene compound methanol solution is 1 g:10-15 g, the volume ratio of diene compound and methanol is 1:2-3. In step (iv), the ratio of amino functionalized graphene oxide and amine compound methanol solution is 1 g:80-120 ml, and the volume ratio of amine compound and methanol is 1:6-10. An INDEPENDENT CLAIM is also included for oil-based drilling fluid comprising 70-90 pts. wt. white oil, 0.5-1 pts. wt. main emulsifying agent, 1-3 pts. wt. auxiliary emulsifying agent, 5-10 pts. wt. fluid loss reducer control agent, 2-5 pts. wt. organic soil, 0.5-5 pts. wt. quicklime, 10-30 pts. wt. calcium chloride (concentration 20-25 %) salt water, 0.5-2 pts. wt. wetting agent, 10-30 pts. wt. barite, 1-10 pts. wt. aminosilane grafted graphene oxide plugging agent.