▎ 摘　　要

NOVELTY - Preparing carboxy modified graphene graft polymer comprises (a) dissolving acrylamide, benzenesulfonic acid, and N-vinylpyrrolidone in water, then adding carboxy-modified graphene, adjusting the pH value of the obtained mixture, adding the first emulsifier to prepare an aqueous phase system, and dissolving the second emulsifier in the oil phase to prepare an oil phase system, (b) mixing aqueous phase system and oil phase system to prepare an inverse emulsion system, (c) adding inverse emulsion system to first initiator for performing first polymerization reaction to obtain an intermediate product system, and then adding intermediate product system to second initiator for performing second polymerization reaction to obtain pre-product, and (d) purifying, drying and crushing pre-product, where the oxygen content in the XPS test result of carboxy modified graphene is not less than 26 wt.%. USE - The carboxy modified graphene graft polymer is useful as fluid loss agent in drilling fluids for oil and gas drilling (claimed). ADVANTAGE - The graft polymer: is used as a fluid loss agent for drilling fluids; and has excellent temperature resistance and salt resistance. DETAILED DESCRIPTION - An INDEPENDENT CLAIM is also included for carboxy modified graphene graft polymer prepared by the above method.