Environment-friendly plugging agent for drilling fluid based on modified basalt fiber powder, and preparation method thereof

The invention discloses an environment-friendly drilling fluid plugging agent based on modified basalt fiber powder. The plugging agent is prepared from, by weight, 50 to 75 parts of basalt fiber powder, 10 to 25 parts of nano silicon dioxide, 1 to 3 parts of surfactant, 1 to 3 parts of silane coupling agent, 2 to 6 parts of ethanol and 10 to 20 parts of polysaccharide polymer, wherein the surfactant is selected from rhamnolipid, soya bean lecithin, sophorolipid or glyceride; the polysaccharide polymer is chitosan, polyfructose or sodium alginate; and the particle size of the basalt fiber powder is 100 to 500 meshes. The plugging agent is mainly used as a plugging agent and a bridging particle for drilling fluid while drilling, the mechanical strength and the compatibility with the drilling fluid are improved, the chemical binding force with the stratum and the membrane efficiency are improved, all the components are environment-friendly materials, the compatibility with the environment is good, and the curre