Recently, the decommissioning of the FPSO “Nanhai Shengli” under Chinese offshore operator CNOOC marked the end of nearly three decades of service in the Liuhua 11-1 oilfield in the South China Sea since 1996.
In February 1987, the CNOOC Nanhai East, in cooperation with a foreign oil company, discovered China’s largest offshore reef tuff oil field, Liuhua 11-1 oil field, with oil reserves exceeding one hundred million tons, at a depth of more than 300 meters in the central part of the Zhujiangkou Basin in the northern part of the South China Sea.
It is understood that the oil field development system consists of a FPS (Floating Production System) “Nanhai Tiaozhan”, which is used for drilling wells and providing underwater support, and a 150,000-ton FPSO “Nanhai Shengli”, which is used to store production facilities and crude oil storage systems.
In recent years, the Liuhua 11-1/4-1 oilfield has achieved recovery rate improvement against the trend, extended its life for nearly 30 years, ushering in the opportunity of secondary development, and the two old facilities have completed their mission and opened the preparation for retirement.
This Liuhua Old Oilfield Disposal Project is the first time in China that facilities are disposed of in deep water.
However, the decommissioning of Nanhai Shengli did not stop operations. CNOOC is in the final stages of completing a new cylindrical FPSO to replace it to ensure continued production from the Liuhua field.
According to the operation plan, CNOOC will accelerate the installation and equipment commissioning of the “Haiji-2” deepwater jacket and cylinder FPSO, to promote the revitalization of the 100 million-ton deepwater old oilfield.