The most northerly commercial harbour in the UK, Lerwick Harbour, has taken delivery of its first decommissioning project from the southern North Sea with the arrival of Spirit Energy’s Markham Field ST-1 platform
The steel jacket and topsides, weighing 2,600 tonnes, were removed in single lifts and shipped by Seaway 7’s heavy-lift crane vessel Seaway Strashnov (ex Oleg Strashnov) to Lerwick Port Authority’s deepwater Dales Voe Base. Seaway Strashnov is a dynamic positioning class 3-capable crane vessel, with a 5,000-tonne capacity revolving crane. Seaway 7 is the renewables and heavy lifting business unit of Subsea 7.
The structures will be dismantled and disposed of by a joint venture of UK-based Veolia ES UK Limited and Peterson UK Limited.
Lerwick port authority chief executive Captain Calum Grains said the decommissioning project “demonstrates for the first time that with the use of cost-effective crane vessels rather than barge transfers to move offshore structures, the port can compete well outside our immediate markets in the central North Sea and northern waters”.
Added Captain Grains, “The ST-1 project strengthens the case we and others have made for Lerwick to become the location for the UK’s ultra-deepwater decommissioning facility, using this technique.
“What we need now is the go-ahead for the facility, building on our capacity, capability and competitiveness to meet the industry’s – and the country’s – future requirements.”
The UK’s Oil & Gas Authority estimated the costs of decommissioning North Sea platforms and abandoned wells at £59Bn (US$73Bn) in 2016.
Lerwick Harbour is currently supporting a number of decommissioning projects – Buchan Alpha J, Dunlin and Leadon – with the Ninian Northern platform jacket and topsides due to arrive in port in 2020.
Now at the end of their working life, recovering these platforms is important to maximise the value of the materials and assets they contain, and further the sustainability of the offshore industry. With a recycling target of 97% the project includes recovery of materials that will be carefully extracted and returned to industry, and where possible assets that have further operational life will be sold for re-use.
ST-1, comprising a 45-m high 1,300-tonne steel jacket and 1,200-tonne topsides structure, was originally installed in 1994 in the Greater Markham Area 160 km off the coast in the southern North Sea. Comprising three levels including a cellar and accommodation unit, a weather deck with pedestal crane and a mezzanine deck, production on this gas platform ceased in April 2016 and was placed in warm suspension mode in September 2017.