In the drilling of Wandi 1 well for basic geological survey of shale gas in Micangshan-Dabashan, the Permian Wujiaping formation thick layer of siliceous limestone and flint limestone were encountered, which were hard and compact with the development of fracture, dissolved fissure and karst caves. The serious circulation loss even no-return happened, which resulted in difficult drilling. Plugging while drilling, bridging material plugging, cement mortar plugging, colloid mud-cement slurry plugging and interception plugging technologies were adopted, no return of drilling fluid was solved.