▎ 摘　　要

NOVELTY - Graphene layer complex comprises graphene oxide and polymer grafted on the graphene oxide, the polymer comprises a structural unit derived from 2-acrylamide-2-methylpropanesulfonic acid and a structural unit derived from the second monomer, where the second monomer includes unsaturated acid and its salt, preferably acrylic acid, methacrylic acid, vinyl sulfonic acid, vinyl sulfonate, vinyl phosphoric acid, vinyl phosphate, maleic acid, maleic anhydride, itaconic acid, fumaric acid, styryl sulfonate, preferably acrylic acid salt and/or hydroxyethyl methacrylate, more preferably acrylic acid and/or methacrylic acid. USE - The graphene layer complex is used as cement slurry additives in the field of oil and gas well cementing, more preferably, based on the total mass of the cement slurry, the mass percentage of the graphene layer complex is 1-10 wt.% (claimed). ADVANTAGE - The graphene layer complex with a specific structure is obtained to achieve the purpose of improving the dispersion performance of graphene materials in cement slurry, at the same time, the layer complex can replace the traditional oil well cement dispersant and play a role in improving the fluidity of the slurry in the cement slurry system. DETAILED DESCRIPTION - An INDEPENDENT CLAIM is also included for preparing graphene layer complex comprising (i) providing a solution A containing the 2-acrylamide-2-methyl propanesulfonic acid and the second monomer, a solution B containing an initiator, a solution C containing a reducing agent, and a solution D containing the graphene oxide, (ii) mixing the solution A, the solution B, the solution C and the solution D to obtain a reaction system, and (iii) reacting the reaction system for a period of time, and stopping the reaction to obtain the graphene layer complex.