Abstract: During the“14th Five-Year Plan”period, China National Offshore Oil Corporation (CNOOC) focused on independent technological innovation. Through theoretical research and key technological breakthroughs, CNOOC successively broke through key technologies such as deepwater complex oil and gas field drilling and completion, open-hole sidetracking in deep and hard formations for multilateral wells, offshore well seismic fusion engineering geological risk identification, and digitalization and intellectualization of offshore drilling. CNOOC developed key equipment such as a localized deepwater underwater production system, a real-time measurement tool for intelligent downhole engineering parameters, a deepwater electro-hydraulic composite intelligent completion tool, and a dual-activity drilling rig, etc. They help to achieve high-quality development of China’s offshore oil industry. As oil and gas exploration and development move deeper into the water and deeper into the strata, deepwater oil and gas drilling and completion operations are facing greater technical challenges. CNOOC will focus on technological research and development in the deepwater and ultra-deepwater fields and achieve systematic breakthroughs and leapfrog development in petroleum engineering technology. It should actively promote green and low-carbon transformation, accelerate digital and intelligent construction, and promote oil and gas reserve increase, production expansion, and high-quality development, providing solid support for ensuring national energy security.