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Marine XII – Installation of a FLNG Mooring System off the Coast of Congo 

Located offshore from Pointe-Noire, the Marine XII project aims to enhance Congo’s gas resources through the deployment of a Floating Liquefied Natural Gas (FLNG) unit. Geocean was commissioned by Wison New Energies, on behalf of ENI, to manage all offshore operations related to the FLNG mooring system.

  • Location Pointe Noire, Congo

  • Solution Transitional energy

  • Key date 2004 - 2005

  • Customer ENI

A Strategic Mooring Operation in Challenging Marine Conditions

The Marine XII project stands out due to the complexity of its operational environment, combining multi-vessel coordination, logistics management in a remote marine setting, and highly precise subsea operations. The primary challenge was to install the foundations, including the three mooring piles and the Yoke base. The second one was to position and secure the Yoke — the critical mooring interface for the FLNG — in an exposed offshore area, while ensuring the structural integrity of the entire gas transfer system.

This high-stakes installation was executed under technically demanding conditions, including:

  • A water depth of 33 meters
  • Large-scale components (Yoke, flexible riser, heavy mooring chains)
  • The simultaneous mobilisation of specialised equipment: jack-up barge, heavy lift vessel (HLV), remotely operated vehicles (ROVs), commercial divers, and platform supply vessels (PSVs)

Engineering, Procurement, Construction & Installation

  • Drilling and installation of 3 mooring piles
  • Insertion and grouting of the Yoke base on piles
  • Lifting and securing of the Yoke via heavy lift vessel
  • Connection and deployment of mooring chains by divers
  • Installation and temporary seabed lay-down of the flexible riser
  • Ballasting operations to ensure final tension and mooring stability