Netherlands contractor Heerema has won the contract to decommission the riser turret mooring (RTM) of the Nganhurra floating production, storage and offloading vessel that had been deployed on Woodside Energy’s Enfield field offshore Western Australia.

Heerema’s workscope includes the integrated engineering, preparation, removal and transportation of the Nganhurra RTM.

The structure will be removed from the Enfield field, located approximately 52 kilometres northwest of Exmouth in WA, by lifting it in one piece onto a barge and transporting the RTM to Henderson or another suitable Australian port for dismantling, and recycling or reuse.

The Nganhurra FPSO is a 270-metre-long, double-hulled, custom-built floater built in 2006 by South Korea’s Samsung Heavy Industries. It was stationed on the Enfield oilfield from June 2006 until late 2018 when the offshore field was shut in.

The floater is designed to produce a maximum of 100,000 barrels per day of oil and can store about 900,000 barrels of oil.

Heerema said it would draw on its more than 30-year experience of decommissioning offshore infrastructure and its track record of “complex lifting operations” to ensure the safe and environmentally sound recovery of the RTM.

“We are proud to be Woodside Energy’s contractor of choice for removing the Nganhurra RTM. This contract represents our first decommissioning project in Australia and although Heerema has a long history of safely and sustainably removing offshore structures from the North Sea and Gulf of Mexico, we are very excited to continue our responsible decommissioning operations in Australian waters,” said Jeroen van Oosten, Heerema’s chief commercial officer.

“Heerema is looking forward to taking an active role in Australia’s decommissioning ambitions.

“The removal and subsequent reuse or recycling of offshore infrastructure is an essential final step in the lifecycle of oil and gas infrastructure and aligns with our company values of responsibility, sustainability and contributing to a circular society.”

The value of Heerema’s contract was not divulged.

Shut-in asset

Woodside earlier this year awarded DOF Subsea a major decommissioning workscope for its shut-in Enfield asset.

The contract, which includes project management, engineering, fabrication and decommissioning services, is expected to be performed in the third and fourth quarters using the contractor’s multi-purpose vessel Skandi Hercules.

DOF Subsea Australia will recover 18 subsea christmas trees, 18 flowbases and associated spool sections, one wellhead severance and up to 18 temporary guide bases from the Enfield field.

Woodside in January submitted a new environmental plan to Australia’s offshore regulator — the National Offshore Petroleum Safety & Environmental Management Authority (Nopsema) — related to additional decommissioning work at Enfield on Block WA-28-L.