EnQuest Achieves Major Decommissioning Milestone with Heather Topsides Removal

EnQuest, a London Stock Exchange-listed energy firm, has reached a significant decommissioning milestone in the UK sector of the North Sea with the help of a heavy lift vessel owned by Allseas, an offshore pipeline installation, heavy lift, and subsea construction contractor.

After receiving regulatory approval in May 2020, EnQuest awarded the Heather topsides removal contract in September 2022, with a single lift operation scheduled for 2025. The removal of the Heather jacket was part of a separate process.

Allseas hired AquaTerra last year to support an Engineering, Preparation, Removal, and Disposal (EPRD) project on EnQuest’s Heather Alpha platform. AquaTerra’s scope of work included providing engineering, fabrication, access, and construction teams for underdeck preparation for topside removal.

The completion of the topsides heavy lift marks a major decommissioning milestone for the North Sea operator. The removal of the Heather Alpha topsides was successfully carried out on August 11, 2025, using the Allseas-owned Pioneering Spirit heavy lift vessel, which lifted the 15,300-tonne topsides in a single operation, the largest planned lift in the North Sea for the year.

The topside was part of the Heather oil field’s infrastructure in the UK sector of the northern North Sea, where oil production began in 1978 and ceased in 2019 for decommissioning. EnQuest has a history of decommissioning, including the plugging and abandonment of over 80 North Sea wells in the past three years.

EnQuest describes the heavy lift operation as the result of extensive planning, engineering, and offshore preparation work by its decommissioning team, working closely with Allseas and other specialist contractors. The Heather topsides are currently en route to Frederikshavn in Denmark for dismantling, with a focus on safe operations.

John Allan, EnQuest’s Decommissioning Director, praised the achievement, stating, “The removal of the Heather Alpha topsides is a tremendous accomplishment for the EnQuest team, as well as our colleagues at Allseas and across the project support network.”

Allan added, “The Pioneering Spirit completed the lift in around 14 seconds, but that astonishing reality was only made possible by three years of meticulous planning, engineering, and preparation works.”

More than 95% of the structure is expected to be recycled and repurposed, ensuring maximum material recovery and minimizing the project’s carbon footprint.

“After almost 50 years of operations in the North Sea, Heather Alpha’s legacy is to be an exemplar of a best-in-class decommissioning project, from inception to the responsible recycling of its materials,” emphasized Allan.