Research and develop domestic high-strength steel and build a digital twin platform, "Haiji No. 2"——
Stand tall in deep water and bravely innovate
About 240 kilometers southeast of Shenzhen, Guangdong, the blue sea surface is undulating. Asia's first deepwater jacket "Haiji No. 2" with a total height of 338.5 meters stands firmly on the seabed 324 meters deep, with more than 10 meters of yellow pipe exposed. The end of the frame is waiting to be "integrated" with the upper oil and gas production platform.
On April 5, with the cooperation of pile driving hammers and underwater robots, the 16th steel pile was "nailed" 134 meters into the seabed stratum. At this point, the underwater piling operations of the "Haiji No. 2" jacket were completed.
Each steel pile is about 170 meters long and 2.7 meters in diameter. The total weight is equivalent to 10,000 cars. Both size and weight are the largest in Asia. "They penetrate deeply into the seabed, allowing the jacket to withstand the test of complex sea conditions." said Wang Deyang, engineer of CNOOC's Liuhua Oilfield Development Project.
Not far away, a red and white grouting boat arrived at the work site to prepare for subsequent grouting operations. The grouting ship fills the gaps between the steel piles and skirt pile sleeves with special cement through the pipeline to make the jacket more stable.
The jacket is equivalent to the "foundation" and is used to support the huge "body" of the offshore oil and gas platform. Looking around the world, there are thousands of jacket production platforms, but less than 10 are used in water depths exceeding 300 meters. The average water depth in the operating sea area of "Haiji No. 2" is about 324 meters, the total weight is 37,000 tons, and the steel consumption is close to the Beijing National Stadium. It is the first time in China that a fixed jacket has been installed in a sea area with a water depth of more than 300 meters.
Deep water installation, huge tonnage, complex sea conditions, every problem is world-class. The CNOOC project team, guided by technological innovation, overcame difficulties and allowed the "Haiji No. 2" to stand more firmly and longer in the seawater——
High-salt, high-humidity environments and impacts such as wind, wave and current put forward higher requirements for the strength of the steel of the jacket. If traditional steel is used, the launch weight of the jacket will reach about 42,000 tons, exceeding the current carrying capacity of domestic and foreign construction sites, construction ships and other resources.
Develop domestically produced high-strength steel to allow the jacket to “reduce fat and gain muscle.” The project team contacted major steel plants for trial production, repeatedly explored and tackled difficulties, and finally developed a new 420 MPa ultra-high-strength steel thick plate. "This material reduces the weight of the jacket by about 5,000 tons, saving hundreds of millions of yuan in materials and ship modification costs." said Fu Dianfu, deputy director of the Engineering Research and Design Institute of CNOOC Research Institute.
"Haiji-2" is rooted in more than 300 meters of deep water. It cannot be seen or touched there. How to monitor it?
Digital twin platforms become the solution.
The installation of equipment and systems such as an offshore data collection and transmission center, 380 sets of monitoring sensors, and a seafloor full-profile flow observation platform allows the land command center more than 240 kilometers away to simulate and generate a digital twin jacket. "Although we can't see or touch it in deep water, we can clearly understand the environmental data such as wind, waves, and currents as well as the jacket status parameters." said Wang Huoping, chief engineer of the Deepwater Engineering Construction Center of CNOOC Shenzhen Branch.
The development of the marine economy has a bright future. Actively cultivating and developing new productive forces is a key step in accelerating the construction of a modern marine industry system. Continuously stimulating new momentum and new advantages with new productive forces will surely promote the high-quality development of my country's marine economy to achieve new and greater results.
Our reporter Ding Yiting
(People's Daily)