On March 26, Asia’s first deepwater jacket “Haiji-2” constructed by China National Offshore Oil Corp (CNOOC), was successfully installed in the Pearl River Mouth Basin. The deepwater jacket set a number of Asian records in terms of operating depth, height, weight, etc., marking that China’s complete set of key technologies and installation capacity of deepwater super-large cdeepwater jacket have reached the world’s first-class level.
Deepwater jacket platform is the most widely used offshore oil and gas production facility in the world, and the deepwater jacket is equivalent to the “foundation”, which is used to support the huge body and huge tonnage of the offshore oil and gas platform. As the first 330-meter deepwater jacket in China, the average water depth of the working area of Haiji-2 is 324.5 meters, and the total height is 338 meters; the weight is 37,000 tons.
Due to the huge tonnage of “Haiji-2” exceeding the lifting capacity of the world’s largest crane vessel, the installation adopts the method of sliding into the water. Using the gravity of “Haiji II” and assisted by hydraulic jacks, the deepwater jacket slides smoothly from the barge into the sea. And then by combining the water injection of the deepwater jacket and the assistance of the lifting ship, the bottom of the deepwater jacket is corrected and accurately seated.
The installation site of “Haiji-2” is located in the Liuhua oil field, about 240 kilometers southeast of Shenzhen, with an applied water depth of about 324 meters. It is the first time for China to install a fixed deepwater jacket in a water depth of more than 300 meters, which is located in a sea with frequent typhoons, strong wind and wave and internal wave currents, making the installation technically difficult and the operational risk extremely high.
Under the operation plan, “Haiji-2” will continue to carry out underwater piling and upper block installation. After the installation completed, it will be applied to China’s first deep-water oilfield – Liuhua 11-1/4-1 Oil Field,boasting proven geological reserves exceeding 100 million tonnes.
It is understood that, compared with the development mode of full underwater production system, the development and construction cost of fixed offshore platform is lower. The successful launching of “Haiji-2” marks an important breakthrough in China’s ability to build deep-water ultra-large fixed offshore platforms, and the ability to choose different development modes according to the actual situation in the development of oil and gas resources in deep-water depths of more than 300 meters.
