PLUGGING AGENT FOR TEMPERATURE-RESISTANT CALCIUM-RESISTANT WATER-BASED DRILLING FLUID USED IN OIL AND GAS RESERVOIR PROTECTION, DRILLING FLUID, AND USES THEREOF

摘要

The present invention relates to the technical field of well drilling, and discloses a plugging agent for temperature-resistant calcium-resistant water-based drilling fluid used in oil and gas reservoir protection, a drilling fluid, and uses of the plugging agent and the drilling fluid. The plugging agent for temperature-resistant calcium-resistant water-based drilling fluid used in oil and gas reservoir protection contains acrylamide-diallyldimethylammonium chloride copolymer modified graphene, wherein in the acrylamide-diallyldimethylammonium chloride copolymer, a molar ratio of structural units provided by acrylamide to structural units provided by diallyldimethylammonium chloride is 1:5-15, and the number-average molecular weight of the acrylamide-diallyldimethylammonium chloride copolymer is 15,000-30,000. The water-based drilling fluid described in the present invention is especially applicable to well drilling in deep salt-gypsum formations, and can exhibit good filtrate reducing, plugging, temperature-resistant, anti-collapsing, and reservoir protection performance.