According to Allseas, the operation involved years of planning and 15 months of offshore preparation, including strengthening and cutting the steel jacket’s six legs for yesterday’s 9-second, 17,000-t lift.
The vessel will now deliver the 44-year-old topsides to Able UK’s Teesside decommissioning yard in northeast England for dismantling and recycling.
Production continues through Brent Charlie, with the vessel also booked to remove that platform’s 34,000-t topsides after operations finally cease.
The Brent Alpha platform is in 140 m (459 ft) of water, 186 km (115 mi) from the northeast coast of the Shetland Islands. As with Delta and Bravo, the 94-m (308-ft) high, 42-m (138-ft) wide topsides comprised multiple decks with living quarters, power generation, process systems, a drilling derrick, flare stack and other facilities.
According to Allseas, this was the first offshore lift to employ specially-developed ‘horseshoes’: connection tools that clamp around pre-installed lift points (bearing brackets) mounted on the upper sections of the jacket’s legs.
Once the Pioneering Spirit arrives at a nearshore location close to the Teesside coastline, it will transfer the topsides to Allseas’ cargo barge Iron Lady for towing up the Seaton Channel and load-in to the quay at Able UK.
This summer, the Pioneering Spirit will go on to remove and transport more than 55,000 t of decommissioned platform infrastructure from UK and Danish fields to disposal/recycling yards around the North Sea region.