China's first deepwater jacket, the "Haiji-II", independently designed and built by China, successfully slid into the water and was precisely positioned in the Zhujiangkou Basin on the 26th, breaking multiple Asian records for operating water depth, height, and weight, indicating that China's complete set of key technologies and installation capabilities for deepwater super-large jackets have reached the world's first-class level, which is of great strategic significance for promoting the increment of offshore oil and gas production and ensuring national energy security.

Guide frame is equivalent to a foundation-supporting the huge body and enormous weight of the offshore oil and gas platform. The "Haiji No.2" guide frame has a total height of 338.5 meters, which is higher than the Beijing Guomao Phase III main building. Its total weight is close to 37,000 tons. The amount of steel used is similar to the "Bird's Nest" National Stadium, making it become the highest and heaviest guide frame in Asia.

Due to the enormous tonnage of Haiji 2, which exceeded the hoisting capacity of the world's largest crane vessel, the offshore installation used a sliding launch method. Liu Huaxiang, general manager of the Liuhua oilfield development project group of China National Offshore Oil Corporation, Shenzhen branch, introduced that this method uses the self-gravity of the guide frame and hydraulic jacks to push the guide frame to slide smoothly into the sea from the barge, and then combines the ballast water of the guide frame and the lifting vessel to achieve upright positioning and precise positioning.

The offshore installation of a deepwater super large jacket faces world-class engineering challenges in complex design calculations, equipment technology capability, and severe sea condition construction. The "Haiji No.2" installation site is located in the Liuhua Oilfield, about 240 kilometers southeast of Shenzhen, with an application water depth of about 324 meters. It is the first time in China to install a fixed jacket in a water depth of over 300 meters. The sea area is prone to typhoons, with strong wind and waves and internal waves, making the installation technology difficult and the operation risk extremely high.

According to Shu Wei, Project Manager of China National Offshore Oil Corporation (CNOOC) Offshore Engineering Liuhua Wellhead Project, the project team has deployed Asian largest submersion barge, "OceanOil 229", and China's largest marine O&G project crane ship, "Blue Whale 7500", to fully enhance the vessel transportation and installation capabilities, and by applying advanced positioning and precise positioning system to adjust the position and attitude of the jacket in the construction process, "Haiji No.2" has achieved precise positioning through 324 meters deep water, with the installation precision reaching the international advanced level.

According to the operation plan, "Haiji 2" will continue to carry out subsequent construction work, such as underwater pile driving and installation of upper modules. After the completion of the offshore installation, it will be applied to China's first deep-water oilfield - Liuhua 11-1 / 4 -1 oilfield to promote the revitalization of billion-ton-level old oilfields. (Cao Xiuyin)

(Source: Science and Technology Daily)