China National Offshore Oil Corporation (CNOOC) achieved a milestone on June 8 with the successful floatover installation of the central processing platform for Phase I of the Kenli 10-2 oilfield development project in Bohai Bay. The platform sets new records in the region for both size and weight, marking significant progress in project construction.
China National Offshore Oil Corporation (CNOOC) announced the successful floatover installation of the central processing platform for Phase I of the Kenli 10-2 oilfield development project in Bohai Bay. [Photo/sasac.gov.cn]
The newly installed platform is a three-deck, eight-leg multifunctional offshore facility integrating production and living quarters. Standing 22.8 meters high with a deck area equivalent to 15 standard basketball courts, it weighs over 20,000 metric tons — making it the largest and heaviest offshore platform ever built in the Bohai Sea.
The team utilized floatover technology to overcome the platform’s considerable weight, surpassing the lifting limits of local offshore cranes. This innovative method harnesses natural tidal forces to seamlessly maneuver the platform topside onto the jacket, resembling a weightlifter’s precise “clean and jerk” technique.
The operation faced multiple challenges, including high loads during transfer, shallow waters at the target site, and only 1.7 meters of clearance between the barge and jacket base. These conditions placed high demands on barge mooring and load management.
According to Shen Liang, project manager for the Kenli 10-2 project, the team used digital twin technology for 3D modeling and analysis to design a precise floatover plan. They independently developed software for multi-pontoon catenary calculations and a dynamic mooring coordination system. The mooring layout was repeatedly optimized, key operations were simulated virtually in advance, and targeted risk mitigation measures were formulated.
During the operation, three AI-enabled positioning systems were deployed, while multiple tugboats worked in coordination to ensure the platform was installed in a single, precise maneuver.
To date, CNOOC has completed 50 large-scale offshore platform floatovers, with a maximum single floatover capacity of 32,000 tons and a cumulative total of over 600,000 tons. The company has mastered a full spectrum of floatover technologies — including high-position, low-position, and dynamic positioning floatovers — positioning it at the forefront of floatover operations in terms of number, difficulty, and complexity.
(Executive editor: Yuan Ting)
