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One of the most technically challenging projects undertaken by Allseas, involving the installation of 660 kilometres of trunklines and infield lines for the deepwater Gorgon- and Jansz-lo gas fields, the largest single resource development in Australian history.
Company: Chevron Australia
Location: Greater Gorgon Area northwest coast of Western Australia
1350 m
Max. water depth
Scope of work
- Installation of 6 trunklines and 15 infield pipelines (total 660 km), with diameters ranging from 6-inch to 34-inch
- Installation of structures (incl. 36x PLETs, ~730x mattresses and 12x adjustable pipe supports)
- Post-lay trenching (burial) of more than 120 km of pipeline
- Fabrication & installation of buckle initiators.
- Flooding, gauging & hydro-testing of complete pipeline system
660 km
Installation of 6 trunklines and 15 infield pipelines
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Specials & challenges
- Super scarp crossings, with (up to) 700 m free-hanging pipelines (very challenging welding criteria)
- Dozens of structure installations
- Fabrication of buckle initiators to maximum allowable sea states (based on Solitaire workability)
- Very shallow water recovery of 34-inch pre-installed pipeline tails with Lorelay
- Narrow tolerances on large PLET installations in deep water
- Extensive pipe supply chain stretching thousands of kms from Kuantan, Malaysia to Dampier and onwards to vessels
- Welding of CRA-lined pipe to stringent standards (incl. use of internal weld inspection tool)
- Laydown of 30-inch pipeline in 1350 m water depth with 50+ buoyancy modules
700 m
free-hanging pipelines
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