Key Technological Breakthroughs and Intelligent Development Pathways for Ultra-Deep Well Drilling and Completion

To address technical challenges such as low drilling efficiency and poor wellbore integrity in China's ultra-deep hydrocarbon development, this study systematically reviews global advancements in ultra-deep well drilling and completion technologies, identifies critical research directions, and supports the efficient exploitation of deep earth resources. Through bibliometric analysis and case studies, we investigated global deep drilling projects exceeding 8,000 m over the past decade, with a focus on comparing international and domestic innovation pathways in wellbore structure design, high-temperature/high-pressure (HTHP) tool development, and intelligent drilling systems. Key findings include: (1) Internationally leading technologies, such as 15,000-m intelligent rigs and self-expanding wellbore structure systems, improve drilling rates by 39% and operational efficiency by 40%-112%; (2) China has achieved breakthroughs in 8,000-m automated rigs and 260 ℃-resistant drilling fluids, yet faces challenges in vibration control of 10,000-m drilling systems and multi-stage pressure regulation (pressure gradient differences >1.8 g/cm3); (3) Fault tree analysis reveals that intelligent trajectory control, nano-composite bit materials, and multi-physics-coupled wellbore integrity are critical for 10,000-m drilling. The study proposes establishing a “geology-engineering-equipment” trinity R&D framework, upgrading ultra-deep drilling acceleration tools, advancing ultra-HTHP wellbore fluids and downhole instruments, and accelerating digital transformation to develop proprietary 10,000-m drilling and completion technologies. By systematically evaluating global technological progress, this work clarifies intergenerational gaps, summarizes China's technical challenges, and provides strategic guidance for future oil and gas engineering innovation, facilitating large-scale exploration and cost-effective development of deep earth resources.