Marine XII project: Installation of the Yoke and Riser

15 July 2025 Projects

Following the installation of the anchor piles and the arrival of the Heavy Lift Vessel (HLV) on site, Marine XII is entering the final stage of the project: the installation of the Yoke and the Riser. These elements are essential to establish the connection between the floating FLNG unit and the subsea infrastructures, thus guaranteeing optimal exploitation of the liquefied natural gas.

An anchoring system specific to gas transport

The gas anchoring and supply system plays a central role in floating liquefied natural gas (FLNG) operation. A floating tank for natural gas, transported from the production platforms and then transferred to a transport vessel. The latter moors alongside the FLNG to load and transport the LNG to a terminal.

This infrastructure provides a mooring and distribution system that guarantees the stability of the process and the safety of offshore operations.

The main stages of installation

Installing the Yoke and Riser is a multi-stage process requiring technical expertise and coordination.

Installing the yoke base

The HLV places the base of the Yoke on the anchoring piles, which have been solidly cemented beforehand.

A second cementing phase is carried out to finalise the link between the base and the anchor piles.

Positioning the Yoke

Once the base is in place, the Yoke, which will serve as the mooring interface for the FLNG, is installed and secured.

Fixing chains

The anchor chains, designed to stabilise the FLNG, are lowered into the water.

The divers connect the chains to the Yoke to ensure a strong anchorage.

Riser installation

The Riser, a key element in gas transportation, is attached to the base of the Yoke. This flexible pipe will link the subsea infrastructures to the FLNG for optimum gas transfer.

Pending commissioning of the FLNG, the Riser is temporarily deposited on the seabed.