UK oil and gas operator Repsol Sinopec has filed a draft decommissioning plan for subsea infrastructure at Buchan & Hannay fields in the North Sea.
The Buchan Alpha Floating Production Unit (FPU) ‘off station’ activities were completed in August 2017 with the sailaway of the platform, so the fields now comprise subsea infrastructure only.
The Buchan field is located c. 154km northeast of Aberdeen and c. 103km from the UK/Norwegian median line in a water depth of c.115 meters. The field was discovered in 1974 and first oil was achieved in May 1981. The Hannay field, discovered in 1996, is located c. 13.5km northwest of the Buchan template in water depth of c. 123 meters.
The Hannay field, which had started production in 2002, comprises two production wells that are currently shut-in and disconnected from the flowlines.
As per the Repsol Sinopec plans, subsea installations will be removed to shore for either re-use, disposal or recycling. Buried and stable pipelines will be left in situ. Surface laid pipelines will be removed to shore for re-use, disposal or recycling.
As for the subsea installations, the plan is to remove them and bring them for recycling onshore. Where piles exist, these will be cut to -3m below the seabed.
Trenched and buried lines will be decommissioned in situ, with remediation of any exposed sections. Surface laid lines will be recovered and returned to shore
“Those lines to be decommissioned in situ are trenched and buried for most of their lengths and will not affect other users of the sea. Surface laid lines will be recovered to shore to prevent future interaction with fishing gear,” Repsol Sinopec said in its draft proposal.
Repsol Sinopec said that the offshore decommissioning activities, which started in 2017 with sail away of the Buchan Alpha FPU, expected to last until 2024 (
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