China National Offshore Oil Corporation (CNOOC) has commenced full operations of the secondary development project at the Liuhua Oilfield, located in the Pearl River Mouth Basin of the northern South China Sea.
The project marks a key milestone in the nation’s effort to sustain offshore output from one of its most productive and historically significant oilfields.
Commissioned in 1996, the Liuhua Oilfield is recognised as China’s first deep-water oilfield and its largest offshore reef limestone field by proven geological reserves.
The oilfield has produced more than 20 million tonnes (mt) of crude oil since coming online.
CNOOC estimates approximately 140mt of recoverable reserves remain, prompting the state-run firm to pursue a secondary development phase aimed at maximising production capacity and extending the field’s lifecycle.
The current phase covers the Liuhua 11-1 and Liuhua 4-1 blocks, situated at an average depth of 305m, highlighting CNOOC’s advanced capability in medium-deep-water development.
The secondary project comprises 32 newly drilled production wells, designed to tap previously inaccessible reserves using upgraded subsea systems and digital monitoring tools.
CNOOC reported that the first batch of wells came online in September 2024, driving record output levels of approximately 3,900 tonnes (t) of crude oil per day.
In a company statement, CNOOC said the Liuhua redevelopment project “represents a major step forward in enhancing the sustainability and efficiency of China’s offshore crude production”.
The project incorporates modern completion technologies, intelligent control systems, and carbon monitoring capabilities aligned with Beijing’s dual carbon targets to peak emissions before 2030 and achieve carbon neutrality by 2060.
CNOOC, which holds a 100 per cent interest in the field through its subsidiary CNOOC China Limited, has been developing deep-water projects across the South China Sea to offset declining output from mature shallow-water fields.
The company produced an estimated 675 million barrels of oil equivalent (boe) in 2024, up about 8 per cent year-on-year, driven largely by new offshore startups, according to its annual report.
The Liuhua 11-1 and 4-1 oilfields are part of the larger Liuhua complex, which originally formed the core of the early regional deep-water development strategy pioneered by CNOOC in the 1990s.
The fields are connected to existing platforms and subsea infrastructure in the Pearl River Mouth Basin, including tie-ins to the FPSO Nanhai Endeavor and CNOOC’s deep-water pipeline network.
Industry analysts note that the secondary development reflects China’s growing offshore engineering expertise.
In addition to the Liuhua upgrade, CNOOC recently started production at the Weizhou 11-4 oilfield adjustment and satellite fields project in the Beibu Gulf Basin, also in the South China Sea.
The project lies in waters around 43m deep and leverages existing nearby infrastructure.
The Weizhou development, which comprises a new unmanned wellhead platform and a central processing platform connected by a trestle bridge, is expected to reach peak production of approximately 16,900 barrels of oil equivalent per day (boe/d) by 2026.
It includes 35 development wells in total — 28 production wells and seven water injection wells — producing high-quality light crude.
CNOOC has positioned both the Liuhua and Weizhou expansions as part of its broader strategy to enhance offshore output from key basins, aiming for continued production growth and greater energy self-reliance.
These projects also align with the company’s 2025 goal of maintaining annual output above 700 million boe while accelerating low-carbon and digital transformation initiatives.
As CNOOC strengthens its deep-water operations, the Liuhua secondary development stands as a showcase of advanced field rejuvenation — reviving one of China’s oldest offshore assets with modern efficiency and sustainability principles.