High efficient plugging agent for well drilling

The invention relates to a plugging agent during well drilling in oil and gas field, and particularly to a high efficient plugging agent for severe lost circulation. The components are, by weight: 18-25% of walnut shell powder, 8-10% of sawdust, 8-10% of cottonseeds, 10-15% of hull powder, 20-30% of active plugging agents, and 15-25% of elastic rubber granules, and the raw materials are mixed uniformly to obtain a high efficient plugging agent for well drilling. According to the invention, the fibrous plugging agent with granules is formed by mixing natural plant inert materials, a synergistic agent, and a reinforcing agent with a certain preparation ratio. The plugging agent of the invention has the advantages of wide covering area for leak stopping, high pressure bearing capacity, good plugging effect, high success rate for disposable leak stopping, simple on-site preparation process, and reliable and safe construction, which can achieve the purposes of reducing loss of lost circulation and saving comprehen