【Major Equipment in the Chemical Engineering Sector】476 – From 2018, domestic underwater valves were used for the first time in Wenchang, Hainan

The Wenchang project has provided an opportunity for the localization of underwater valves. Li Daquan, general manager of the Limited Zhanjiang Engineering Construction Center, explained that underwater valves are core equipment in underwater production systems. Underwater production systems developed in the 1960s can be combined with facilities such as floating production platforms to form various modes of offshore oil field development. Compared to building expensive offshore oil production platforms, this system can significantly reduce investment costs and is less affected by natural disasters, making it highly suitable for the development of deep-water and marginal oil and gas fields. Compared to land-based valves, underwater valves must withstand external water pressure, are operated by ROVs (underwater robots) or hydraulically, and require higher levels of sealing and corrosion resistance. The related technology and market are currently in the hands of a few foreign valve manufacturers, while in China, development is still in its initial stages. Faced with challenges such as high prices for underwater valve imports, long supply cycles, and limited opportunities for subsequent maintenance, relevant departments at China National Offshore Oil Corporation, including the Office in Charge of the \"Three New and Three Modernization\" initiatives and the Engineering Construction Department, have paid close attention to the development of domestic alternatives. Building on previous research and development efforts, it was decided to conduct tests and implement these alternatives in the development project of the Wenchang gas field complex in the western South China Sea. The Wenchang Gas Field Cluster development project plans to develop the three marginal gas fields of Wenchang 9-2, 9-3, and 10-3. The resource sharing infrastructure in the vicinity of this gas field cluster is poor; the water depth in the surrounding sea areas exceeds 100 meters, and strong winds and high waves prevail throughout the year. The demands of downstream users are very high. Taking various factors into account, the limited Zhanjiang project plans to build a new platform and a set of underwater production facilities, which presents new opportunities for the localization of underwater valves.

The Limited Zhanjiang Wenchang Project Team and CNOOC Engineering Design Company are responsible for studying and analyzing the technical aspects of underwater valves. They actively organized expert inspections, selected high-quality domestic valve manufacturers, and carried out prototype manufacturing, testing, and certification as required. Following this process, the localization of underwater valves progressed rapidly in the Wenchang project: work on verifying the feasibility of local production of such valves began at the end of 2015 ； The feasibility study report was completed in January 2016 ； The following month, invitations were sent to 4 manufacturers to develop domestic versions of underwater valves ； In March 2016, the domestic production approach and implementation plan for underwater valves were reviewed once again, and several domestic manufacturers were invited to participate in the development of prototype units for underwater valves as part of the Wenchang project ； In April 2016, memorandums confirming the participation of four manufacturers in the trial production of the domestic prototype were officially received. In August 2016, the results of this effort became apparent: two manufacturers were unable to complete the tests on time due to issues, while the other two manufacturers successfully carried out the design, manufacturing, testing, and factory certification of the prototypes in accordance with the technical approach and timeline for local production of underwater valves for the Wenchang project. Subsequently, domestically produced underwater valves were officially manufactured in factories and put into use. Throughout the period of local production of these underwater valves, the professional technicians from the Zhanjiang Wenchang project team and CNOOC Engineering Design Company identified all the quality risks associated with their development, overcame various challenges, and implemented comprehensive quality control throughout the design, material selection, manufacturing, and testing processes. Together with the manufacturers, they succeeded in solving issues related to corrosion resistance underwater, external pressure at the sea floor, underwater actuators, and valve reliability. Prototypes were manufactured, and they passed the performance, service life, and high-pressure chamber tests specified by the American Petroleum Institute (API). As a result, a set of technical documents and guidelines for the design, material selection, manufacturing, and testing of locally produced underwater valves was developed.