Acid-soluble pressure-bearing plugging agent for drilling fluid, and preparation method thereof

The invention discloses an acid-soluble pressure-bearing plugging agent for a drilling fluid, and a preparation method thereof. The acid-soluble pressure-bearing plugging agent comprises, by weight, 20-30 parts of crop straw extracted fibers, 5-10 parts of polyester fibers, 5-10 parts of cellulose acetate, 10-20 parts of glass fibers, 5-10 parts of asbestos fibers, 10-20 parts of cotton and hemp plant fibers, 10-20 parts of rock-forming mineral powder, 5-10 parts of alginate, 3-5 parts of dimethyl diallyl ammonium chloride, 3-5 parts of polyvinyl acetate, 1-5 parts of n-octyl alpha-cyanoacrylate, 1-4 parts of diatomite and an appropriate amount of clear water. The crop straw extracted fibers with a low cost are used as the main body raw material for the plugging agent in order to well achieve the purposes of ensuring the plugging effect and the pressure bearing effect of the plugging agent and saving the production cost of the plugging agent. The preparation method greatly enhances theplugging effect of the p