Abstract: During the 14th Five Year Plan, China National Petroleum Corporation (CNPC) has focused on the exploration and development of the "six oil and three gas" basins. In response to the engineering challenges posed by high temperature, high pressure, and complex geological environments, CNPC has continuously iterated and upgraded its engineering technology, achieving a large number of technological achievements and supporting the rapid development of key technologies for deep, ultra deep, and unconventional horizontal well drilling and completion. We have developed key technologies centered around a 15000m drilling rig, optimization of unconventional wellbore structures, safe, efficient, and fast drilling, high-temperature resistant drilling fluids, precision controlled pressure drilling completion, and expansion tubing. We have successfully carried out a number of iconic ultra deep and horizontal well drilling operations. The deep well drilling capacity has exceeded 9000m, the horizontal section length of the horizontal well has exceeded 5000m, and the "one drilling" footage has reached a maximum of 3700m. This has promoted the discovery and development of large oil and gas fields such as Tarim Fuman, Sichuan Shuangyushi, and Daqing Gulong, providing strong engineering and technical support for improving the intensity and efficiency of oil and gas resource development. With the continuous advancement of oil and gas exploration and development, drilling still faces engineering geological risks and new challenges. Further research is needed to accurately predict formation pressure, optimize and expand wellbore structure, control wellbore trajectory, develop high-temperature resistant working fluid systems, efficiently break rocks and speed up tools, and integrate geological engineering to achieve continuous iteration and upgrading of key drilling technologies and equipment, and support efficient exploration and development of deep, ultra deep, and unconventional oil and gas resources.