On August 20th, China National Offshore Oil Corporation (CNOOC) announced that the "Deep Sea No.1" atmospheric field has successfully completed its first offshore pipeline cleaning operation since its production, marking the successful completion of China's first ultra deep water pipeline cleaning operation. This is of great significance for ensuring the long-term safe and stable operation of ultra deep water gas fields and energy supply, and further promoting China's marine technology self-reliance and self-reliance. The "Deep Sea No.1" atmospheric field adopts the model of "ultra deep water underwater production system+semi submersible production platform" to develop marine natural gas resources. The underwater production system is deployed in two areas of the east and west in the sea area with a depth of 1500 meters, and connected to the water surface and underwater production facilities through submarine pipelines. The peak annual gas production exceeds 3 billion cubic meters. The subsea pipeline is known as the 'blood vessel of offshore oil and gas fields', which ensures the smooth transportation of offshore oil and gas, while at the same time, there may be problems such as' thrombosis' blockage or' plaque 'corrosion. "Zhang Bao, the production supervisor of the" Deepsea No.1 "gas field, said that to ensure the safety and smooth flow of the subsea pipeline, offshore oil and gas fields will regularly carry out pigging operations to clean up the sediment and liquid accumulated during the operation of the subsea pipeline, and also detect the internal situation of the pipeline, In the industry, it is commonly known as "Tongqiu". Zhang Bao introduced that the "Deep Sea No.1" gas field has designed and deployed three sets of submarine pipeline "ball passing" devices, which are respectively used to carry out pigging operations for the internal production facilities of the eastern and western areas of the gas field, as well as for the export pipelines. The ultra deep water subsea pipeline cleaning operation implemented this time only targets the subsea pipelines of internal production facilities in the gas field, with a total distance of over 100 kilometers for "ball passing". Natural gas is prone to form hydrates under low temperature and high pressure conditions, so there may be pipeline "ice blockage" during the gas transmission process of ultra deep water gas field pipelines, which sharply increases the risk of pipeline "sticking". Li Zhi, the director of "Deepsea No.1" gas field, stated that the difficulty of implementing ultra deep water gas field pipeline cleaning operations is much greater than that of shallow water oil and gas fields. China National Offshore Oil Technology Team starts from the technical principles, A complete technical response plan has been developed based on the actual situation of ultra deep water gas fields, ensuring that every operational risk can be effectively controlled. It is understood that after analyzing the output of this pigging operation, the China National Offshore Oil Corporation (CNOOC) technical team has certified that the production subsea pipelines of the "Deep Sea No.1" gas field are in good operating condition, in line with design expectations, once again verifying the reliability of the design and quality of China's first ultra deep water gas field underwater facilities. (Reporter Xiuying Cao) (Xinhua News Agency)