Abstract:
Ultra-deep and super-deep reservoirs contain vast oil and gas resources, primarily concentrated in the Sichuan Basin, Tarim Basin, and Junggar Basin. These reservoirs represent a critical strategic replacement field for China’s exploration and development efforts. In recent years, drilling depth in China has broken through the 9 000-meter mark, with some wells exceeding 10 000-meter. This paper systematically analyzes the geological and engineering challenges faced in ultra-deep and super-deep reservoirs, reviews recent advancements in reservoir stimulation and testing engineering technologies for such reservoirs and proposes future research directions for stimulation and testing in 10 000-meter reservoirs. Theoretical research and oil & gas exploration practices indicate that ultra-deep and super-deep reservoirs, characterized by complex lithology, ultra-high pressure and temperature, high sulfur content, and high productivity, can’t be explored by existing reservoir stimulation and testing technologies. Through research and integrated solutions in engineering design, process technology, tubing & equipment, and tool materials for carbonate rocks stimulation and testing in ultra-deep and super-deep reservoirs, multiple adaptive technologies have been developed in the Tarim and Sichuan Basins. These achievements have realized critical objectives “tubing can be run to depth, reservoirs can be fractured, wellbores can be effectively sealed, yield can be accurately tested, oil and gas can be efficiently produced” in ultra-deep and super-deep reservoirs. High-yield wells with exceeding 1 000 tons per day have been successively discovered in oilfields such as Shunbei, Fuman, Pengzhou, and Yuanba. To further develop ultra-deep and super-deep reservoirs, this paper proposes focused research on foundational theories, process technologies, tools and fluids, and ground equipment for reservoir stimulation and testing at depths beyond 8 000-meter, particularly targeting “10 000-meter” super-deep reservoirs. Accelerating breakthroughs in key core technologies and equipment, along with gradual localization, will support the high-quality exploration and cost-effective development of China’s ultra-deep and super-deep resources.