On May 29th, after a 17 day and over 1300 nautical mile voyage, China's first self-designed and constructed cylindrical "offshore oil and gas processing plant" in Asia, "Sea Kui No.1", arrived in the waters of Liuhua Oilfield, laying the foundation for China's first deepwater oilfield secondary development project to be put into operation within the year.

Haikui No.1 "is a high-end marine equipment that integrates crude oil production, storage, and export functions. It consists of nearly 600000 components, with a total weight of nearly 37000 tons, equivalent to 30000 cars. It has a height of nearly 30 floors, a main deck area equivalent to 13 standard basketball courts, and a maximum storage capacity of 60000 tons. It can process about 5600 tons of crude oil per day. The "Sea Anemone One" is designed for a once-in-a-century severe sea condition, with a designed lifespan of 30 years, and can operate continuously at sea for 15 years without returning to the dock.

Haikui No.1 has arrived at the operating sea area of Liuhua Oilfield. Photo by Wang Jiqiang

According to Li Longxiang, the head of the offshore installation team for the secondary development project of Liuhua Oilfield at China National Offshore Oil Corporation Shenzhen Branch, "Haikui No.1" itself has no power and cannot sail on its own at sea. In order to shorten the sailing time, reduce transportation risks such as seawater impact damage and typhoon impact, "Haikui No.1" innovatively adopts a combination of "large ship carrying small boat" and "small boat towing large ship" transportation methods. Firstly, it is loaded onto a large semi submersible transport ship like cargo, transported to an anchorage in Guangdong, and then separated and unloaded from the ship. Finally, "Haikui No.1" is towed to Liuhua Oilfield by a high-powered tugboat for reconnection and installation.

The "Sea Anemone One" departed from Qingdao, Shandong on May 12th aboard the largest semi submersible transport ship in Asia, the "Xin Guang Hua". During the towing process, it crossed the Yellow Sea, East China Sea, and Taiwan Strait, with a total voyage of over 1300 nautical miles. Due to the large weight and volume of the "Sea Anemone One", the draft depth is close to the critical channel limit, and the cylindrical structure has a high center of gravity, poor stability, and is prone to rotation, which puts extremely high demands on loading, unloading, and long-distance towing.

The "Sea Anemone One" was towed by three high-powered tugboats to the construction area. Photo by Yu Changbao

The project team has overcome technical challenges such as transportation design, scheme preparation, and complex calculations for ultra large structures. They have developed emergency plans and conducted emergency drills for nearly 20 extreme situations, established an emergency support system for sea land linkage, and scientifically responded to various complex situations such as ocean surges, severe weather, and fishing intensive areas. With the joint efforts of all staff, the 'Haikui No.1' was transported to the operating sea area three days in advance, "said Wang Jiqiang, the installation project manager of the 'Haikui No.1' project at Haiyou Engineering.

Haikui-1 "is the world's first" digitalized "cylindrical floating production, storage, and unloading oil device that integrates multiple systems such as integrated ocean monitoring, data integration platform, and mechanical equipment health management. After arrival, it will be connected to anchor legs pre installed in the deep sea through 12 2570 meter long mooring lines and float on the sea at a depth of 324 meters. The oilfield has pioneered a new development model of "over 300 meter deepwater pipeline frame+cylindrical floating production storage and unloading device" in China, providing a new choice for efficient development of deepwater oil and gas fields.