Inpex wraps up mooring chains pre-lay for Ichthys project off Australia

The Inpex-operated Ichthys LNG Project has reached a milestone by completing the offshore mooring system pre-lay in the Browse Basin, located off the northern coast of Western Australia.

Inpex, a Japanese energy company, said on Wednesday that part of the mooring system for the project has been set up. The 77 kilometer chain and mooring system consists of 49 chains laid on the seabed in water depths of up to 250 meters and anchored to foundation piles—5.5 meters in diameter and 63 meters long.

The mooring system will, according to Inpex, secure the project’s two massive offshore facilities—the central processing facility (CPF) and floating production, storage and offloading (FPSO) facility—on the Ichthys Field seabed for at least 40 years of continuous operation.

The company said the CPF will deliver natural gas via 890 kilometer subsea gas export pipeline to onshore processing facilities in the Northern Territory while most of the condensate will be processed through the FPSO and shipped directly to market from the Field.

Inpex said the large-scale anchor chains weigh 40,000 tonnes and that the 28 CPF mooring chains required more than 25,000 tonnes of mainly 178 millimeter diameter chain, while the 21 FPSO mooring chains needed more than 15,000 tonnes of mainly 161 millimeter diameter chain.

Ichthys Project Managing Director Louis Bon said:”Despite the difficulty of the task, I’m proud to say that it was successfully completed without a single Lost Time Injury or any harm to the environment.”

“For example, because the Ichthys Field is located just 120 kilometers from the main hump back whale migratory routes and calving grounds of North West Australia, an early decision was made to avoid pile driving during the whale calving period where associated underwater noise may have created a disturbance.”

Bon further said the mooring chains pre-lay completion was a major milestone ahead of the the CPF and FPSO arrival, currently under construction in South Korea.

“The offshore facilities will operate for decades and the mooring system plays a key role in ensuring their integrity.” said Bon.

Inpex added that in addition to the mooring system, more than 16,000 tonnes of subsea structures and 140 kilometers of rigid flowlines have been installed across the Ichthys Field to safely and efficiently extract gas and condensate.