Floating Storage and Offloading (FSO) disconnection, removal and towing

12 Sep 2025

FSO decommissioning - Disconnection, laydown and recovery of mooring chains

Project overview

Location

Gulf of Thailand

Solution

FSO decommissioning

Intermoor, Acteon’s Moorings and Anchors business line, completed the decommissioning of an FSO vessel, which had been in service for over two decades in 70 m water depth.

Expertise, strong coordination and cost efficiency all around

The decommissioning campaign involved complex offshore operations, including disconnecting and laying down flexible risers and mooring chains, towing the FSO to Singapore, and recovering subsea infrastructure for processing in Thailand.  

Challenges included logistical, technical, and operational issues, such as modifying the FSO for safe disconnection, multi-party coordination, tight sequencing, storage limitations onboard the vessel and schedule constraints. 

Intermoor's solution involved chartering and managing the marine spread, selecting and mobilising specialist equipment, and deploying experienced personnel. The project was coordinated from Singapore, leveraging local contractors for cost efficiency.  

The team minimised decommissioning costs by  

  • repurposing existing equipment
  • optimising deck layouts and chain handling techniques to enable single-trip recoveries
  • adjusting vessel movements and scopes to avoid delays
  • and minimising environmental impact through proactive waste management and contingency planning.  

The result

Intermoor delivered end-to-end support for the FSO decommissioning campaign. This included: 

  • Chartering and managing the marine spread.
  • Selecting and mobilising specialist equipment.
  • Deploying experienced personnel to manage complex offshore operations. 

This integrated approach ensured safe, efficient execution aligned with the customer’s decommissioning and asset transfer objectives. This marked Intermoor APAC’s first decommissioning campaign and was delivered in parallel with a large-scale pipeline campaign. Early engagement with the customer ensured alignment on objectives and smooth execution throughout the operation. 

 

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