On May 11, my country's first domestically produced deep-water underwater Christmas tree was installed on the seabed in Yinggehai, Hainan. This equipment is an important part of the underwater oil and gas production system engineering demonstration project led by CNOOC, marking my country A key step has been taken in the development of key technical equipment for deepwater oil and gas development. The 500-meter-level underwater oil and gas production system engineering demonstration application project implemented by CNOOC marks that my country has the ability to design, construct and apply complete sets of equipment.

Subsea production system is the key equipment for developing deepwater oil and gas fields, including subsea wellhead, subsea Christmas tree, subsea control system, subsea manifold 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 for the equipment. In 2018, CNOOC took the initiative to boldly propose that it needs to use self-developed 500-meter-level underwater equipment to develop deepwater oil and gas, and accelerate the breakthrough of key core technologies in deepwater.

The water pressure at a depth of 500 meters is equivalent to about 50 times the atmospheric pressure. In the face of the complex environment such as low temperature and complex landforms on the seabed, and 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 In the face of severe technical challenges, there is no chance for trial and error, and any negligence may cause huge irreparable losses.

Even so, Mi Lijun, president of CNOOC Research Institute, who is in charge of 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 toward the deep sea, and has accumulated With more than ten years of experience in underwater design, it is the unshirkable responsibility of CNOOC people to develop deep-water oil and gas in the South China Sea with independent technology.

To realize the autonomy of underwater equipment, we must first realize the autonomous capability of underwater design technology. However, it is easier said than done to carry out the design of the 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; second, the domestic underwater equipment technology is generally low in maturity and has not yet formed a complete The third is the lack of a systematic technical system. In order to control the reliability of the independently designed underwater production system from the source, the CNOOC Research Institute has comprehensively explored the design source and fully identified the risks of the underwater production system scheme. However, the international common analysis scheme is an underwater production system based on mature components, while the underwater equipment developed in this project generally adopts 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 absorbing international underwater product standards and technical management, developed a set of technology maturity assessment system based on self-developed underwater production system according to local conditions. Carry out an item-by-item analysis of the hundreds of key components of each equipment, and apply it only after the final evaluation is qualified, so as to ensure the high reliability of the product and control the implementation of the first set of products from the source. risk.

In order to successfully apply the self-developed underwater equipment, in addition to the development and testing in accordance with the most stringent international 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 it must rely on independent research to obtain international access recognition.

During the research and development process of the underwater control system, CNOOC Research Institute completed the overall scheme design, achieved breakthroughs in six core key technologies, and laid the foundation for product development. After more than three years of technical research, CNOOC has led the cooperation with 16 domestic units including CSSC and has acquired the independent research and development capabilities of the underwater "Four King Kongs". Taking the underwater Christmas tree developed in this project as an example, there are as many as 2,591 parts including various valve groups and control modules, and the independent research and development rate is as high as 90%.

During the 18-month research and development process of the subsea wellhead, three high- performance technological innovations were realized, 81 factory tests and 28 onshore water environment expansion tests were carried out, which fully verified the reliability and functionality, and successfully achieved domestic And the double certification of foreign classification societies.

At present, my country's first 500-meter-class fully underwater production system has successfully completed the sea trial and integration test, and is about to enter the offshore installation stage. It is expected to achieve demonstration operation by the end of 2022.

Xie Yuhong, chief scientist of CNOOC and project director of scientific research projects, said that only by breaking through the development of deep-water underwater production systems can we firmly grasp 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 national energy security.