How do you secure a ship 500 metres long and six times heavier than an aircraft carrier to the seafloor for 25 years?
This is the challenge facing the multibillion-dollar Prelude Floating Liquefied Natural Gas (LNG) plant, which is to be secured in 250 metres of water off Australia’s north-west coast.
But it’s also the sort of question that will become increasingly common as we look to deeper and deeper water for our energy resources.
“As the industry attempts to push the floating LNG concept into areas more than a kilometre deep, they’ll be looking for new types of anchors, and that’s what we’re working on now,” says Australian Research Council Laureate Fellow Mark Cassidy from The University of Western Australia.
A geotechnical engineer by trade, Mark’s work underpins the engineering design of the anchors securing our offshore platforms, floating gas processing plants, pipelines, and wind and wave energy generators.
His team conducts model tests on soils they collect from around the world, determining how various anchors will perform in different locations.
What he wants to know is: when you pull on one of these anchors, how much load will it take before it breaks free?
“We need to ensure that, even in a large cyclonic event, the offshore platforms remain securely attached to the seabed,” says Mark.
As a result of their work the team have now developed software to assist engineers to design the right anchors for their site, and their work has been written into the international engineering standards.