The central platform of Liwan 3-1, Asia's largest offshore oil and gas platform owned by CNOOC, was successfully upgraded

The Liwan 3-1 gas field is China's first deep-water gas field with a water depth of about 1,500 meters. As one of the important gas sources in the Guangdong-Hong Kong-Macao Greater Bay Area, the natural gas produced in the Liwan 3-1 gas field is transported to the Zhuhai Gaolan terminal through a submarine pipeline on the Liwan 3-1 central platform at a water depth of 200 meters. Since the start of production in 2014, the cumulative production of deep water gas fields such as Liwan 3-1 has exceeded 30 billion cubic meters.

The Liwan 3-1 central platform serves as the "transportation hub" for the large-scale production of deepwater gas fields. Previously, with the increase of the mining life and the access of new gas fields such as Liuhua 29-1, the first-phase equipment of the platform gradually failed to meet the requirements for natural gas processing. The platform upgrade project will fully release the production capacity of Liwan 3-1 and other gas fields.

This platform upgrade and transformation is faced with problems such as multiple project interfaces, high difficulty, and complex process flow. The engineering project team carried out a number of technological innovations and practices to realize safe and efficient cutting and replacement of process pipelines, and completed the multi-point precise installation of 2500 tons of modules. During the offshore transformation and construction process of the production high-pressure gas field platform, no recordable safety incident occurred, and no production shutdown was caused outside the planned schedule.

After the upgrade project is completed, the pressure of the deep-water submarine pipeline from the Liwan 3-1 gas field to the central platform will be reduced by 75%, and the platform will also enable dual-pipe production, adding 3 wet gas compressors and 3 condensate oil transfer pumps. The pressurization equipment reduces the pressure of the offshore pipeline, reduces the formation of hydrates during the natural gas transportation process, and improves the integrity of the equipment.