Micro-nano anti-collapse blocking agent for drilling fluid, and preparation method of micro-nano anti-collapse blocking agent

The invention discloses a micro-nano anti-collapse blocking agent for drilling fluid, and a preparation method of the micro-nano anti-collapse blocking agent. The blocking agent is prepared from the following raw materials in parts by weight: 5-20 parts of epoxy resin, 5-15 parts of itaconic acid, 10-38 parts of acrylic acid, 15-35 parts of 2-acrylamide-2-methyl propanesulfonic acid, 2-10 parts ofpH modifier, 1-6 parts of emulsifying agent, 0.2-1.0 part of initiator, 5-15 parts of solvent and 50-150 parts of water. Compared with the prior art, the blocking agent has nano-scale and micro-nano-scale deformable particles, thus reducing filtrate loss, adjusting rheological property, and being good in heat resistance, free from fluorescence and good in compatibility; furthermore, a molecular chain of the blocking agent has a variety of absorption groups, so that the blocking agent can be absorbed on the surfaces of the clay particles so as to repair a filter cake formed by the filling of the particles in the drill