First Set of Domestic Deep-Water Production Tree Installed

Qian Wei

“5, 4, 3, 2, 1! Underwater robot unlocked! Everything is working normally, the oil production tree lowering succeeds!” Recently, after 21 hours of hard work on the “Nanhai 7” drilling platform in the Yingge Sea area of the South China Sea, the underwater robot successfully unlocked the running tools of the production tree,and the first set of domestic deep-water subsea production tree developed by the CSSC Chongqing Qianwei Technologies(CQQW) successfully completed the seabed installation.

As an important part of the engineering demonstration project of underwater oil and gas production system of the Ministry of Industry and Information Technology (MIIT), it marks a key step forward in the development of key technology and equipment for deep-water oil and gas development in China.

For a long time, the underwater production tree has been monopolized by only a few foreign companies. The high price and limited use of imported underwater production tree have long restricted the pace of China's offshore oil going to deep water. In 2010,CQQW had in mind the national ocean energy development strategy, aiming at core and key product localization of the offshore oil equipment industry,organized a team, made overall planning of resources, carried out R&D, production and services of the underwater wellhead device and production tree, control system, and supporting installation tools, provided system solutions to offshore oil and gas resources development, committed to break the key bottleneck of China’s ocean resources development.

In 2019, based on the core technologies accumulated in leading the implementation of the national project, CQQW participated in the MIIT “Demonstration and application of underwater production system localization” special project led by CNOOC. The company firmly believes that only by breaking through the development of deep-water subsea production system, can the key to open the deep-sea oil and gas exploration and development be firmly held in its own hand.

“Design water depth of 1,500 meters, 20 years of service life, 10,000 Psi (pound force / square inch) rated working pressure (equivalent to 150 times atmospheric pressure),minimum rated working temperature of minus18 degrees Celsius,stringent equip mentsealing strength and material bearing capacity requirements...” In order to achieve better development results, CQQW headed for world-class technical difficulty in the outset.

Among more than 500 design documents, 2,560 kinds of parts,11,000 design drawings, and more than 1,000 tests, the design team complied with the international most stringent standards, conducted structure and electrical design, finite element analysis and calculation, product performance test and land integration test and sea trial test, all tests were certified by the industry authoritative third party, finally all were qualified.

After 36 months of research,despite the impact of the COVID-19 epidemic and the export restrictions of high-tech products in Europe and the United States, all the project staff worked overtime, still stuck to work during holidays, overcame many difficulties, and finally ushered in the smooth installation of the first deepwater subsea production tree in China.This shows that CQQW has successfully mastered the design, manufacturing and testing technology of deep-water subsea production tree, and successfully completed tackling the sci-tech hardnut problem -- development of key technology and equipment for deepwater oil and gas development.

The subsea production system will be used to develop gas reservoirs around the Ledong platform in the Dongfang 1-1 gas field, where the gas well applying the subsea production system can produce about 200 million m3 natural gas per year.