China's first offshore ultra-high temperature and ultra-high pressure gas field production platform has been installed in place

On November 3, China National Offshore Oil (CNOOC) announced that with the upper block of the platform weighing more than 1,900 tons falling steadily on the riser, China's first offshore ultra-high temperature and ultra-high pressure gas field production platform - Ledong 10-1 gas field production platform completed offshore installation, after putting into operation, the peak annual output of nearly 600 million cubic meters. It is of great significance to improve the development ability of complex offshore oil and gas resources and ensure national energy security.

Heavy Duty 122 ship carrying Ledong 10-1 gas field upper block near offshore oil 201 ship

The Ledong 10-1 gas field development project is located in Yinggehai Basin, south of Hainan Island, about 113 kilometers away from Sanya City, Hainan Province, with an average operating water depth of about 90 meters. It was first discovered in 2015. The reservoir temperature of the gas field is as high as 214℃, and the formation pressure is as high as 94 mpa, reaching the standard of ultra-high temperature and ultra-high pressure gas field, which is the first offshore gas field in China.

The upper block of Ledong 10-1 gas field was lifted and 122 heavy duty ships sailed away

"This gas field is located in an area with extreme temperature and pressure conditions and a lot of uncertainties, which makes it a huge challenge for us to develop it." Chang Huxing, general manager of Engineering Construction Center of CNOOC Hainan Branch, introduced that the Ledong 10-1 gas field development project fully relies on the development and construction of oil and gas production facilities, and plans to build a new unmanned wellhead platform with 4 legs and 8 pettipile, equipped with specially designed high temperature and high pressure oil and gas production equipment, which is connected to the central platform of Ledong 22-1 gas field through submarine cables and gas transmission pipelines. Power supply and oil and gas processing capacity are obtained, and the oil and gas produced is eventually sent to the Eastern terminal for processing and sales.

Overlooking the closure of upper block and jacket in Ledong 10-1 gas field

The installation of the platform is made up of two parts: the production unit on the surface and the jacket under the water, with a total weight of 9,200 tons. Among them, the jacket is the "base", which is installed by the construction scheme of "horizontal construction, drag loading, hoisting and launching, filling with water and righting", and has been fixed on October 5; The upper block of the platform was hoisted to the top of the jacket by the "Offshore Oil 201" pipe laying crane, and slowly lowered to complete the docking.

According to Yu Faling, chief engineer at the site of Ledong 10-1 gas field development project of CNOOC, the installation of the new platform of Ledong 10-1 gas field is greatly affected by bad weather and submarine tidal current at sea, and the weight and height of the vessel are close to the limit of the operation capacity of the crane ship. The CNOOC project team researched and formulated the five-level construction plan, optimized the construction technology, adopted the ship's head-up operation mode to overcome the influence of ocean current, and completed the installation of the jacket bottom within the 75-hour limit operation window. At the same time, through real-time fine control of ship dynamics, the upper block and jacket can be accurately closed.

The upper block of Ledong 10-1 gas field slowly moved towards the jacket

Jiang Ping, deputy general manager and chief engineer (development) of CNOOC Hainan Branch, said that the Ledong 10-1 gas field development project is an important practical exploration of CNOOC to promote the substantive development of offshore ultra-high temperature and ultra-high pressure oil and gas, which is expected to break through a number of technical limits of offshore oil and gas development, and establish a technical system for exploration and development of offshore complex oil and gas resources. Further releasing the resource potential of Yinggehai Basin is of great significance to fully building the trillion-atmosphere area of the South China Sea and increasing the rate of energy self-sufficiency.