Aiming at the complex problem of mudstone formation leakage and collapse in Liujiagou, Shiqianfeng and Shihezi formations in Jin30 well area of Dongsheng gas field, this study systematically revealed the instability mechanism of mudstone formations through indoor rock analysis (mudstone core observation, X-ray diffraction mineral composition analysis, scanning electron microscopy and thin slice analysis) and physical and chemical performance tests. The study shows that the mudstone formations in this area have the characteristics of high clay mineral content and multi-scale fracture development, and are prone to clay hydration expansion and fracture expansion during drilling, resulting in well wall instability. Based on this, a well wall stabilization technology with the core of inhibiting clay hydration swelling and strengthening multi-scale fracture plugging is proposed., Through indoor research and field application verification, the developed multi-salt ratio high-performance compound salt drilling fluid realizes effective control of hard and brittle mudstone in the long naked eye section, and significantly improves the well wall stability. In the industrial test of 11 wells in Dongsheng Gas Field, the drilling period was shortened by 36% year-on-year, and the output was increased by 26.7% compared with the allotment. The research results provide important technical support for solving the problem of efficient drilling in complex mudstone formations, and provide theoretical basis and practical reference for oil and gas exploration and development under similar geological conditions. It provides technical support for efficient drilling of mudstone formation in Jin30 well area of Dongsheng gas field.