Fossil Energy – Decommissioning
Allseas’ Pioneering Spirit vessel has completed a single-lift removal of the 15,300-mt topsides from the Heather Alpha platform, 460 km northeast of Aberdeen.
It was the largest planned single-lift operation in the North Sea this year.
The 14-second lift followed three years of detailed engineering, planning and offshore preparation under a collaboration between EnQuest and various contractors.
Allseas started its preparations for the task last year, installing custom-made lift points on the topsides, also performing structural strengthening, caisson works and separation cuts. Much of this activity took place while the platform was still manned.
Early this year, Allseas’ teams returned to complete the underdeck scopes related to leg cutting and separation.
The teams worked alongside specialist rope access crews to address weather and operational constraints to keep the project on schedule.
“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. 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.”
