The Brent Field has four topsides (platforms), Brent Alpha, Bravo, Charlie and Delta.
Combined, the four topsides weigh in total some 100,000 tonnes. Each of the four platforms has a topside. This is the surface deck of a platform that contains equipment for drilling, producing and processing oil and gas, as well as the accommodation block and helipad. Each topside needs to be taken to shore for recycling and disposal.
OPSAR Decision 98/3 states that topsides must be removed.
Throughout the contracting process, several yards in the UK and Norway were considered before the successful award to Able UK in Teesside.
The topside on the Brent Delta platform, weighing 24,200 tonnes, will be removed as one piece by a new vessel that has been designed and constructed by Allseas, a Swiss-based company. The vessel is called the Pioneering Spirit. Using this single lift technique marks a major departure from traditional decommissioning methods where the topside is usually taken apart piece by piece in situ offshore.
After detailed technical and engineering studies, this technique was chosen for three compelling reasons: it will substantially reduce the safety risk, cost and environmental impact of the operation compared with other methods. It is estimated that over 97% of the topside will then be recycled once it is brought to shore in Teesside.