Preparation method of polyacrylamide potassium salt coated inhibitor for drilling fluid

The invention belongs to the technical field of oilfield drilling fluid treating agents, and particularly relates to a preparation method of a polyacrylamide potassium salt coating inhibitor for drilling fluid. The preparation method provided by the invention comprises the following steps: (1) uniformly stirring and mixing an aqueous solution of an acrylamide monomer, a hydrolytic agent, disodium ethylene diamine tetraacetate and urea, then adding a redox initiator for stirring reaction under the protection of nitrogen and at the set temperature of 20-40 DEG C, stopping stirring when the temperature of a reaction system is 2-3 DEG C higher than the set temperature, and carrying out solid-liquid separation to obtain a solid; transferring the obtained reactant, and continuously reacting for 5-7 hours to obtain a spongy product; and (2) crushing, drying and crushing the spongy product to obtain the product. According to the invention, a simple hydrolytic polymerization method is adopted, so that the purpose of c