Bundles and towed installation

Bundles and towed installation

11

BUNDLE DESIGN

CONSIDERATIONS

CONSIDERATIONS

Flowlines diameter and wall material and thickness

CP protection Sizing and spacing of anodes

Carrier wall thickness handling, towout (fatigue), expansion and pullout forces internal N 2 pressure balance Carrier diameter fit all flowline components C of G below C of B

Tow and trailheads fit valves and pipework withstand towout forces stability during tow protection against fishing stability on seabed (piles) connection to bulkhead

Ballast chains centres number of links 30 N/m (2 lbf/ft) net negative buoyancy

Bulkheads forces

Thermal design insulation active heating (continuous and from startup)

Spacers support rollers flowline buckling

thermal leakage

Bundle design considerations are: 1. Flowline pipes are designed as normally : The pipeline bore is sized to suit the throughput.

Material selection is based on product flows throughout the design life. The wall thickness is sized to suit internal pressure requirements. Insulation is provided to suit thermal and hydrostatic pressure. 2. Spacer units : These are designed to suit the specific configuration of flowlines and umbilicals. They need to provide sufficiently frequent support to prevent bending for all the sizes of contents. The spacing may be closer at ends in order to prevent buckling under thermal loading. Some spacers incorporate rollers to enable the flowlines be drawn within the carrier.