Abstract: The Jingyan-Qianwei Area has developed various structures such as stretching, compression, and strike slip, with overall crack development. The southwest of the areas is characterized by multiple intersecting faults and complex fractures. The drilling process of exploratory wells deployed in the early stage mainly faces the following challenges: There are many leakage points in the formation, difficulties in quick inclination prevention in straight sections and in well trajectory controling; the mechanical drilling speed is slow. In order to safely and efficiently explore and develop shale gas in this block, a safety drilling technology has been developed with the optimization of differentiated three opening wellbore structure, integrated geological engineering track design to avoid fracture solution, pressure drop density control technology to control complex overflow and leakage, and multi-stage high-efficiency plugging technology as the core. The key to this technology is the anti collapse drilling fluid system, integrated drilling parameters of drill bits and drilling tools, and four in one geological guidance. Technology integration is applied to 9 wells, with an average drilling encounter rate of 100% for high-quality reservoirs, an average drilling speed of 1.9 m/h to 8.6 m/h, and a drilling cycle of 233 d to 72 d. Practice has shown that the formed safe, efficient and fast drilling technology not only provides technical support for safe and efficient exploration and development, but also provides technical guarantees for increasing storage and ore preservation, as well as sustained and stable production.

Key words: Jingyan-Qianwei Area, Qiongzhusi Formation, shale gas, safe and efficient drilling technology