Woodside Energy highlighted the challenges of its flagship Pluto project, a large liquefied natural gas (LNG) development that started production last year offshore northwest Australia. “We brought together local and international expertise to face these challenges, and it was because of their hard work and innovation that we were actually able to overcome these challenges,” said Feisal Ahmed, executive vice president of technology at Woodside, at an OTC topical breakfast.
The AUD 15 billion greenfield project centers on the 2005 Pluto gas discovery and integrates offshore, subsea, and onshore components. The field lies 190 km northwest of Karratha, Western Australia, and 800 km north of Perth. Subsequently, Woodside discovered the nearby Xena field and will develop it as a tie-in to the Pluto facility in the future. Together, the fields hold a 5 Tcf gas resource.
“The key here is first LNG production in 2012,” Ahmed said, referring to Pluto. “I don’t think I have seen anything that has been even close to the time frame of this project. Normally, they end up being in the high teens, even 20 or 30 years from discovery to final production.”
Pluto comprises five big-bore subsea wells in approximately 800 m of water that produce between 720 MMcf/D and 800 MMcf/D of gas. Dual 20-in. pipelines, tied back 27 km over a steeply rising escarpment, connect the wells to a riser platform in 85 m of water. The platform is normally unstaffed. A 36-in. production pipeline tied back 180 km, along with a continuous-injection MEG line to combat hydrates over the long tieback, connect the platform with an onshore LNG processing train on the Burrup Peninsula.
The project has four dedicated LNG transport vessels to carry shipments to customers and recently delivered its 50th sales cargo, Ahmed said.
A major challenge for LNG projects is project expense, particularly in the high-cost Australian construction market. Among the ways that Woodside managed the cost was by drilling large wellbores to accommodate 95/8-in. production tubing. While a comparable facility might have 15 or 20 wells, Ahmed said, Pluto has five wells and needs only three producers to serve the plant. “We’ve got a couple of insurance wells out there because it is an LNG facility that needs constant production to deliver the plateau volumes,” he said.
In addition, Woodside achieved large savings by building the plant with prefabricated megamodules, making Pluto the world’s first LNG facility to do so.
Very unusual seabed conditions created challenges for building pipelines and the platform foundation, which Woodside addressed by a high level of front-end engineering to select the best pipeline routes and to minimize stabilization issues, Ahmed said.
The project also worked successfully with government regulators to protect and ensure minimal impact on indigenous rock art along the Dampier Archipelago.
When Pluto received its final investment decision (FID) in 2007, Australia’s only LNG facility was the huge Woodside-operated Northwest Shelf project, which has produced since the 1980s. There were no new LNG projects slated. Today, seven projects involving 13 processing trains, including Pluto, have received FID, Ahmed said.