Trunkline Magazine 08 Jul 2021

Reel success for Julimar

Working closely with contractors has delivered what is believed to be the biggest diameter corrosion resistant alloy pipeline ever “spooled” around a reel.

Woodside has worked closely with EPCI contractor Subsea 7 to deliver what might well be the biggest diameter of corrosion-resistant alloy (CRA) pipeline ever reeled.

The installation commenced in Q2 for the Julimar Development Phase 2 (JDP2) Project.

Spooling massive lengths of pipe around a reel on the deck of a pipelay vessel might seem to defy physics but Pipeline Engineer Stewart Allen says it is a well-established method of pipelay that has the benefit of lower cost.

And though it’s not new, Stewart says the system hasn’t been used by Woodside since the Echo Yodel project in the early 2000s.

“Reel-lay enables the potential for cost savings by pre-fabricating the majority of the pipeline onshore,” Stewart explains, adding there are also many health and safety benefits accrued by moving offshore exposure hours to onshore.

“This required a newly constructed purpose-built and dedicated spoolbase in Bintan Indonesia, with sufficient space to store long lengths of pipeline, called ‘stalks’.

“The trade-off, however, is that the vessel must transit back and forth between the field and the spoolbase to collect the pipe. This has always proved a challenge due to the remoteness of our assets.”

In 2019, Woodside awarded contractor Subsea 7 a contract to deliver 22 km of 18 inch CRA-clad gas transmission flowline and an umbilical system.

Reeling CRA pipe of such large diameter is thought to be a world first.

“The previous largest was 16 inch diameter CRA pipe,” notes Stewart.

“Following extensive engineering and testing, the project gained confidence that the larger diameter pipe is technically acceptable.”

Ben Witton of Subsea and Pipelines has been responsible for managing delivery of the contract with Subsea 7 and notes there were many technical challenges.

“But through close collaboration with Subsea 7, the appropriate risk mitigations have been identified, tested and implemented,” he says.

The first reeling was undertaken at the Bintan spoolbase in May, reeling the first of three 7 km lengths of pipe on to the Seven Oceans pipelay vessel.

Laying on the seabed then followed and is expected to be completed in Q3.

Located some 200 km off the north west of WA, the Julimar project will supply gas and condensate from the Julimar reserve (via existing Phase 1 infrastructure) to the Chevron-operated Wheatstone Platform, and then onshore to Wheatstone’s LNG plant.

The Bintan facilities offer opportunities for future projects along the north west coast.

Read the Q2 2021 edition of Trunkline here.