Troll Phase 3 - Stage 2

Offshore pipelay
Pioneering Spirit
Lorelay
Oceanic
PS on Troll Phase 3 Stage 2

Installation of gas export pipeline, including inline tees and associated subsea structures, supporting continued gas production from the Troll West field to the Troll A platform

Company: Equinor

Location: Northern North Sea (approx. 80 km northwest of Bergen, Norway)

Water depth: 300 - 350 metres

Trunkline installation close to live infrastructure 

Structures designed & built in-house

Strict welding & qualification criteria carried over from Stage 1 

Scope of work 

  • Installation of 28-km, 36-inch, concrete‑weight‑coated (CWC) gas pipeline, parallel to the Troll Phase 3 – Stage 1 pipeline installed by Solitaire in 2020
  • Fabrication & installation of subsea structures (incl. 3 inline tees (ILTs) and mudmats)
  • Installation (and removal) of counteracts
  • Pre- and post-lay survey
  • Commissioning (FGT) of the complete system
deploying buoyancy modules and providing ROV and survey support

Specials & challenges 

  • Installation extremely close to existing live pipelines (parallel to Stage 1 pipeline), requiring precise navigation, ILT positioning, and controlled laydown operation
  • Complex ILT installation sequence at three separate locations
  • Lift‑and‑shift manoeuvres at laydown location to install a laydown connector onto pre-installed manifold
  • Counteract installation/removal complexity due to high‑mass modules and tight installation windows
  • Strict adherence to welding and qualification philosophy carried over from Stage 1 
Counteracts loadout
Loadout of in-house ILTs at AFBV
Start-up near Troll A
ROV shots
Pipelay by PS
Laydown head
Lorelay on standby
Dolphin team
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