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Watch: Ichthys Offshore Pipelay Project

Published Apr 24, 2017 3:12 AM by The Maritime Executive

Italian oil and gas contractor, Saipem, has released a video of its work to complete the 890-kilometer gas export offshore pipeline for the Inpex-led Ichthys LNG project in Australia. At peak production, the pipelay rate exceeded 4.4 km/day.

The 42-inch gas export pipeline will transfer gas to the LNG process plant in Darwin, Australia. 

The pipeline is the longest in the southern hemisphere and the third longest in the world, and the work was undertaken from the Semac 1 in shallow water and the Castorone in deepwater.

Installation of the subsea infrastructure was completed in January this year. The field includes a subsea network spread across a 400 square kilometer (155 square mile) area of the Ichthys Field at depths of around 250 meters (820 feet).

Included in the subsea gathering system is a 110 meter riser support structure, five manifolds, 139 kilometers (86 miles) of flowlines, 49 kilometers (30 miles) of umbilicals and flying leads, 2,640 tons of production and MEG spools, five subsea distribution units and a subsea distribution hub.   

The project was now ready for the arrival of the central processing facility (CPF) and FPSO, currently under commissioning in South Korea. The CPF is a column-stabilized, offshore semi-submersible production unit supporting hydrocarbon processing systems and utilities, as well as living quarters for about 200 people. It will be the world’s largest semi-submersible platform and is being constructed in South Korea at the Samsung Heavy Industries shipyard.

The project’s FPSO will be used for condensate dewatering, stabilization, storage and export. The 336-meter (1,100-foot) ship-shaped, weather-vaning vessel is being constructed in Korea by Daewoo Shipbuilding and Marine Engineering. It has been designed to hold more than one million barrels of condensate.

Once all commissioning activities in the South Korean shipyards are finished, the offshore facilities will be towed to the Ichthys Field and moored for their 40 year operational life by 40,000 tons of chain secured to more than 25,000 tons of foundation piles.

The Ichthys field has reserves estimates from two geological horizons of around twelve trillion cubic feet of gas and five hundred million barrels of condensate. This makes it the largest discovery of hydrocarbon liquids in Australia in more than 40 years.

When operational, the project is expected to produce 8.4 million tons of LNG and 1.6 million tons of LPG per annum, along with approximately 100,000 barrels of condensate per day at peak.