Chevron Gorgon Jansz

General information

Client Chevron Australia 
Project Chevron Gorgon Jansz 
Year 2012 – 2014  
Location North West Shelf, offshore Western Australia 
Vessels Lorelay, Solitaire 
Max. water depth 2164 m (7100 ft)

Scope of work

  • Installation of 6 trunklines and 15 infield pipelines (totalling 659,769 m), with diameters ranging from 6-inch to 34-inch
  • Installation of various structures including 36 PLETs, 734 mattresses and 12 adjustable pipe supports
  • Trenching of more than 120 km of pipeline
  • Flooding, gauging and hydro testing of pipelines
  • Fabrication and installation of 11 buckle initiators

Project specials

  • Super scarp crossings (700 m free-hanging pipelines)
  • Structure installations
  • Fabrication of 11 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
  • Free span crossings (700 m free-hanging pipelines over the scarp); extremely challenging welding criteria
  • Extensive pipe supply chain from Malaysia to Dampier and onwards to vessels
  • Welding of corrosion-resistant alloy (CRA) lined pipe to high standards, including use of internal weld inspection tool
  • Laydown of the 30-inch pipeline in 1350 m of water depth with 50+ buoyancy modules

Pipe characteristics

136.021 6.625 12.0 DNV SMLS 450
62.274 6.625 14.0 DNV SMLS 450
28.867 7.625 22.5 DNV SMLS 450
64.089 8.625 12.0 DNV SMLS 450
62.328 8.625 13.5 DNV SMLS 450
55.106 8.625 14.3 DNV SMLS 450
28.887 9.625 21.0 DNV SMLS 360
8.208 24 27.1+3.0 DNV DSAW 450 + UNO 316L
0.107 24 27.1+3.0 DNV DSAW 450 + UNO 625
0.074 24 44.3+3.0 DNV DSAW 450 + UNO 316L
21.770 26 31.2+3.0 DNV DSAW 450 + UNO 316L
1.289 26 31.7+3.0 DNV DSAW 450 + UNO 625
40.249 30 34.2 DNV DSAW 450
30.447 30 36.6 DNV DSAW 450
0.667 30 56.9 DNV DSAW 450
61.733 34 31.2 DNV DSAW 450
57.654 34 38 DNV DSAW 459

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