Bundles and towed installation

Bundles and towed installation

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GIRASSOL PROJECT – WET (FREE-FLOODING) BUNDLES

ƒ Twin 219.1 mm (8 ⅝ in) flowlines ƒ 1.1 to 2.9 km (0.7 to 1.8 miles) long ƒ Syntactic foam insulation/buoyancy ƒ Bottom tow 220 km (140 miles) ƒ 1300 m (4265 ft) depth

The Girassol field was developed using a number of bundles from the bases of the hybrid towers out to the well centres. The bundles each consist of a 762 mm (30 in) diameter outer carrier containing a pair of 219.1 mm (8⅝ in) diameter production lines enclosed in syntactic foam. The foam acted as both insulation and buoyancy. It was specially developed for the project to insulate the flowlines from the high seabed pressure -130 bar (1.885 ksi) at a water depth of 1300 m (4265 ft) – and a very low ambient temperature of around 3 °C (37 °F). The carrier is allowed to ‘free flood’ and is used to protect the flowlines and transfer the installation loads. These bundles are each between 1.1 km to 2.9 km (0.7 miles to 1.8 miles) long. The bundles were fabricated in Angola and bottom-towed over a distance of 220 km (140 miles) on the seabed, with depths of up to 1300 m (4265 ft) along the route. At the time of installation, there was little existing infrastructure at Girassol, so some of the disadvantages of bottom tow did not apply.

FLAT-PACKBUNDLES