China's CNOOC Ltd is considering deploying a Sevan-type floating production, storage and offloading vessel for the redevelopment of its Liuhua 11-1 and Liuhua 1-4 field complex in the South China Sea's Pearl River Mouth basin.

Sources told Upstream that CNOOC has decided to favour a circular FPSO rather than a ship-shaped vessel to further develop the twin Liuhua fields.

They added that CNOOC and Sevan Marine - now owned by Singapore’s Sembcorp Marine - had earlier completed a conceptual study on the feasibility to deploy a circular floater to develop oilfields in the South China Sea.

It is not clear if CNOOC will buy a licence from Sembcorp Marine to apply the FPSO under a Sevan design in the South China Sea, though the joint study agreement envisages both CNOOC and Sevan being allowed to make use of the design.

Sources said that the unit will likely accommodate a drill equipment package to make it a floating drilling, production, storage and offloading vessel.

If confirmed, such an FDPSO would replace CNOOC’s original plan to deploy a tension-leg platform and an FPSO to develop the new reserves at the two Liuhua fields.

If a project emerges it would be the first Sevan type FPSO deployment in the South China Sea.

Seven Marine has been promoting the circular FPSO concept to CNOOC for years so it could apply the new type of floater in the South China Sea and CNOOC has also been on the lookout for a potential target field for its application.

The Liuhua 11-1 field has been in production since 1993.

It was not considered viable for further development as recently as last year, when the low oil prices of the preceding years continued to dominate sentiment.

A Liuhua re-development could be put on the fast track because CNOOC is focusing more on offshore activities at home amid government calls to boost domestic oil and gas production to reduce reliance on imports.

The Liuhua 11-1 and Liuhua 1-4 fields are currently serviced by the Nanhai Shengli FPSO, which is has been in production since 1993.

The floater went through a major overhaul in 2006 after being badly damaged by Typhoon Pearl.

The new Liuhua 11-1 area reservoir is about six kilometres south-east of the existing Liuhua 11-1 field in a water depth of 340 metres. Discovered in 1987, Liuhua 11-1, which is 190 southeast of Hong Kong, originally held 200 million tonnes of proven oil reserves, with oil production having peaked at 50,000 barrels per day a few years ago.