Abstract: The development of low-permeability reservoirs has become the key area of oil and gas exploration and development, and the drilling & completion-based engineering technologies are the key elements for the efficient development of low-permeability oil and gas reservoirs. During the " Thirteenth Five-Year Plan” period, to address technical challenges encountered in the exploration and development of low-permeability reservoirs such as the western Sichuan and Jiyang Depression, studies on key technologies for the high-efficiency development of low-permeability reservoirs have been conducted, which mainly focused on drilling speed-up, efficiency enhancement and engineering cost reduction. It has lead to significant progress on the aspects of 175 °C MWD system, near-bit gamma imaging system, new drilling speed-up tools, full-process reservoir protection technology, long-term sealing cementing technology, fine staged completion technology, etc.. Accordingly, key drilling & completion technologies for the high-efficiency development of low-permeability oil and gas reservoirs have been established preliminarily, and the field applications in Block Yan 222 of Jiyang Depression and the low-permeability Zhongjiang Gas Field in the western Sichuan achieved stellar results including remarkable cost reduction and efficiency enhancement, which have laid a solid foundation for efficient development of drilling & completion technologies and efficient exploration of various low-permeability reservoirs.