China's Underwater Valve Realizes Localization and Breaks Foreign Technology Monopoly

A few days ago, CNOOC's Zhanjiang branch company in Guangdong (hereinafter referred to as Zhanjiang) had news that the two domestic underwater ball valves of the Nanhai Wenchang Gasfield Group Development Project had been delivered and passed acceptance inspections recently. At this point, China's underwater valves succeeded in achieving localization, breaking the monopoly of foreign technology, purchasing prices fell by more than 40%, and greatly shortened the delivery period.

It is understood that underwater valves are the core equipment of underwater production systems. The underwater production system developed in the 60th century can be combined with floating production platforms and other facilities to constitute different offshore oilfield development models. Compared to the construction of an expensive offshore oil production platform, the system can significantly reduce investment costs and is less affected by natural disasters. It is very suitable for the development of deepwater and marginal oil and gas fields.

Compared with land valves, underwater valves have the characteristics of being subject to external water pressure, driven by ROV (hydraulic robot) or hydraulic drive, and have higher requirements for tightness and corrosion resistance, and their technologies and markets have been kept in a few foreign countries. In the hands of a valve company, China is still in the research and development stage.

Faced with the difficulties of high import prices for underwater valves, long lead times, and limited maintenance at later stages, CNOOC’s “Three New and Three Chemicals” leadership office, the Ministry of Construction, and other related departments are highly concerned about localization work. Based on the above, it is determined to carry out experiments and applications in the development project of the Wenchang Gas Field Group in the western part of the South China Sea.

The Wenchang Gasfield Group Development Project plans to develop the Wenchang Gas Field 9-2, 9-3, 10-3 marginal gas fields. The resource sharing foundation around the gas field group is poor, the water depth of the sea area is more than one hundred meters, and the wind and waves are high all year round, and the downstream users are demanding. Integrating various factors, the limited Zhanjiang plans to build a new platform and an underwater production facility, which will bring new opportunities for the localization of underwater valves.

The limited Zhanjiang Wenchang project team and the COOEC engineering design company are responsible for researching and combing the technical points of underwater valves. They actively organize experts to inspect, select domestic valve manufacturers, and perform prototype manufacturing, testing, and certification according to requirements.

During the localization of the entire underwater valve, the professional technicians of the limited Zhanjiang Wenchang project team and the COOEC engineering company fully identified the quality risk points during the research and development of underwater valves, and worked hard to overcome difficulties, and implemented the design, materials, manufacturing, and testing processes. Comprehensive quality control, together with the manufacturers successfully solved the problems of underwater corrosion, submarine pressure, underwater actuators, valve reliability, etc., manufactured the prototype, and passed the API's performance, service life and high pressure cabin. The test has formed a set of technical documents and procedures for the design, selection, manufacture and inspection of domestically produced underwater valves.