The first deepwater jacket in Asia, Haiji-1, was independently designed and built by China. It was successfully slipped into the water and put into position accurately. It officially settled in the Lufeng 15-1 oil field, setting a new record for the offshore installation of deepwater jackets in Asia, marking China's deepwater jacket. The complete set of key technologies and installation capabilities of super-large jackets have reached the world-class level.

This operation is the first time in China to install a fixed jacket in a water depth of nearly 300 meters. In order to successfully put the jacket, which is 302 meters high and weighs more than 30,000 tons, the CNOOC project team has formed an all-star lineup of top Asian marine engineering ships.

Since the weight of "Haiji-1" exceeds the hoisting capacity of the world's largest floating crane, the offshore installation is carried out by means of slip launching.

The project personnel cut in strict accordance with the operation plan, and then used the self-gravity of the jacket, with the help of hydraulic jacks, to smoothly slide the jacket from the barge into the sea. After slipping into the water, "Haiji No. 1" was "lying" on the sea surface. At this time, "Blue Whale" took action to use the righting rigging to cooperate with precise water injection, and straightened the "flat" jacket step by step until it was completely "Land", standing firmly in the predetermined position. With the perfect cooperation of the three main operation vessels and the underwater robot, 12 steel piles were successively inserted into the corresponding skirt sleeves, which were precisely positioned and rooted on the seabed. The azimuth angle, levelness and position deviation all met the requirements. The project team will then use special cement to fill the gap between the steel pile and the skirt sleeve, which is often referred to as "grouting" in the industry.

After the operation, "Haiji No. 1" has been firmly fixed on the seabed, and the "new home" with a water depth of about 284 meters. In the next step, "Haiji-1" will be "integrated" with the future "partner" upper block. After the platform is completed, it will set a new weight record for China's offshore crude oil production platform.Editor/Ma Xue