In the Exmouth sub-basin, offshore Northwest Australia, Apache Energy is developing the Van Gogh oilfield on behalf of a joint venture of the same name.
‘As part of the Vincent field, it lies in water depths of 340 to 370 meters. An FPSO will be used for production and storage of the oil. The FPSO will be moored to a disconnectable turret-mooring (DTM) buoy, moored to the seabed with nine anchors. Flexible flowlines, which connect to two subsea manifolds and the production wellheads, will be attached to the buoy. In the event of storms or cyclones, the FPSO will be able to disconnect from the buoy and sail to calmer waters. The offshore installation contractor for the Van Gogh project, Acergy Australia, has asked Jumbo of the Netherlands to take care of the transportation of the massive DTM buoy from Singapore to the Exmouth gulf, delivering sub-sea equipment to the subsea installation vessel ‘Toisa Proteus’, and demobiliding equipment from the ‘Toisa Proteus’ to Singapore. Beside the normal engineering procedure, additional brainwork was required in the preparation phase of the project. Lifting the DTM buoy was only possible from the top, using a single point connection. A special lifting device to suspend the “ball tool” was designed in-house and manufactured under supervision of Jumbo in Singapore.