On May 11, my country's first domestically produced deepwater subsea oil tree was installed in the sea area of Yinggehai, Hainan. This equipment is an important part of the subsea oil and gas production system engineering demonstration project led by CNOOC, marking a key step in the development of key technology and equipment for deepwater oil and gas development in my country. The 500-meter underwater oil and gas production system engineering demonstration application project implemented by CNOOC this time marks that my country has the ability to design, construct and apply complete sets of equipment.
The subsea production system is the key equipment for the development of deepwater oil and gas fields, including subsea wellheads, subsea Christmas trees, subsea control systems, subsea manifolds and other equipment. For a long time, only five European and American companies in the world have mastered the integrated manufacturing technology of underwater production systems, resulting in long procurement cycles, high prices and difficult maintenance of the equipment. In 2018, CNOOC took the initiative and boldly proposed the need to use self-developed 500-meter underwater equipment to develop deepwater oil and gas, and accelerate the breakthrough of key deepwater core technologies.
The water pressure at a water depth of 500 meters is equivalent to about 50 times the atmospheric pressure. Facing the intricate environment such as low temperature on the seabed and complex landforms, and the harsh conditions of 20 years of maintenance-free, the sealing strength of underwater equipment, the pressure-bearing capacity of materials, and the quality of workmanship are facing severe technical challenges. There is no opportunity for trial and error, and any negligence may cause irreparable huge losses.
Even so, Mi Lijun, president of CNOOC Research Institute, who is responsible for the development and design of the 500-meter-level underwater oil and gas production system engineering demonstration application project, believes that the underwater production system is an important part of China's progress towards the deep sea. He has accumulated more than ten years of underwater design experience. It is the bounden duty of CNOOC people to develop deepwater oil and gas in the South China Sea with independent technology.
In order to successfully apply self-developed underwater equipment, in addition to being developed and tested in accordance with international stringent product standards, it must be fully witnessed and approved by an authoritative third-party organization. Therefore, it is definitely not feasible to copy foreign underwater equipment technology, and must rely on independent research to obtain international access approval.
During the research and development process of the underwater control system, CNOOC Research Institute completed the overall scheme design and achieved breakthroughs in six core key technologies, laying the foundation for product development. Through more than three years of technical research, China National Offshore Oil Corporation has taken the lead in uniting 16 units including China State Shipbuilding Corporation to have the independent research and development capabilities of the underwater "Four Diamonds". Taking the underwater Christmas tree developed in this project as an example, the number of components including various valve groups and control modules is as high as 2,591, and the independent research and development rate is as high as 90%.
During the 18-month research and development process of the underwater wellhead, three high-performance technological innovations were realized, 81 factory tests and 28 terrestrial water environment expansion tests were carried out, which fully verified the reliability and functionality, and successfully obtained the dual certification of domestic and foreign classification societies.
At present, my country's 500-meter-level fully underwater production system has successfully completed sea trials and integration tests, and is about to enter the stage of offshore installation. It is expected to achieve demonstration operation before the end of 2022.
Xie Yuhong, Chief Scientist of CNOOC and project director of scientific research projects, said that only by making breakthroughs in the development of deep-water underwater production systems can we firmly hold the key to deep-sea oil and gas exploration and development in our own hands. In the future, CNOOC will continue to strengthen original and leading scientific and technological research, develop offshore oil and gas resources with equipment with independent property rights, and strive to make more and greater contributions to ensuring energy security.
In order to realize the autonomy of underwater equipment, it is necessary to realize the autonomous capability of underwater design technology. However, it is not easy to carry out the design of underwater production system independently. First, the domestic underwater technical team is in its infancy, and there are only a handful of talents with deepwater engineering experience; In order to control the reliability of the self-designed underwater production system from the source, CNOOC Research Institute has comprehensively investigated and fully identified the risks of the underwater production system at the source of the design. However, the international general analysis scheme is based on the underwater production system of mature components, while the underwater equipment developed in this project generally uses domestic components. How to control the application risk of the first set of products, relying on the original conventional technical means is very limited.
In order to ensure the smooth implementation and operation of this demonstration project, the research team, on the basis of fully digesting and assimilating international underwater product standards and technical management, and adapting to local conditions, developed a set of technology maturity evaluation system based on self-developed underwater production system. It analyzes hundreds of key components of each equipment item by item, and only after passing the final evaluation can it be applied, so as to ensure the high reliability of the product and control the implementation risk of the first set of products from the source.
