A floating production (FPSO) vessel moored over the Bualuang oil field in the Gulf of Thailand damaged a production riser after drifting off station in bad weather.
The Rubicon Vantage FPSO drifted into the exclusion zone designed to protect the production infrastructure.
The Vantage’s mooring chains then came into contact with, and damaged, the production riser, resulting in oil being observed on the surface.
Production was immediately halted and operations launched to clean up the discharge, estimated at about 20 bbl. The oil was dispersed within a five-hour period, said operator Salamander Energy
Salamander said further inspection work and repairs are underway and the FPSO owner has made arrangements for a new production riser to be fitted, if required. This would see production re-commence around Jan. 15, 2014.
Salamander is investing in the Bualuang oil field, in Block B8/38. In 2012, it installed a new production platform.
New power and processing modules are being constructed, and are due to be installed on the Bravo wellhead platform platform early this year. This will aid plans to replace the Rubicon Vantage FPSO with a floating storage and offloading vessel (FSO), to reduce costs.
The new FSO, which will be installed later this year, will have a turret mooring system with 360 degree swivel capability, with no need for an exclusion zone, and hence the risk of this kind of incident being repeated will be removed.
Salamander has signed an LOI with Teekay for an FSO, scheduled to be on location in mid-2014.
It is drilling 16 new development wells on the field, as part of a program started in 2012, to grow production by at least 50%. It also planned to drill six exploration prospects on the nearby G4/50 license.
For the development drilling, Salamander is using the Atwood Mako rig. Development drilling was not impacted by the shut-in.
According to Salamander, the Bualuang oil field has 46MM bbl recoverable 2P reserves. There is thought to be a further 12 MMbo of resources in reservoirs above and below the main T4 reservoir.