Decommissioning and abandonment

Decommissioning and abandonment

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COSTS

ENVIRONMENTALANDFINANCIALCOSTS

ENVIRONMENTAL AND FINANCIAL COSTS ƒ In all cases, cleaning is required ƒ Burial contracts placed ‘at-cost’

ƒ Limited data to date for HAZOP/SAFOP ƒ Qualitative rather than quantitative assessments ƒ All lift and recovery has safety issues ƒ Outweighs leave in-situ by a factor of ten ƒ Risks to divers ƒ Steel and concrete reclamation not cost-effective ƒ Anodes depleted

For all options, it is necessary to first clean the pipeline. Burial contracts for those pipelines that require reburial or deeper burial have been let in Norway to CTC. These have been bid on the basis that work will only be carried out if the vessels and trenching equipment have no other work. The rates are quoted per kilometre buried, and are effectively charged at minimal costs to keep the equipment busy in off seasons. If other commitments do not allow any work in a particular year, it can be passed over to the following quiet period. Pipelines up to 1524 mm (60 in) are trenched on a one- pass ‘reasonable endeavours’ basis. Because there have been very limited removal operations to date, the hazard or safety assessments are necessarily of a qualitative nature. The salvage costs for the materials do not nearly make the operations cost-effective. With the exception of removal of anodes – which can cause metal pollution of the seabed – there are little environmental benefits either. Where: HAZOP = hazard and operability (analysis study) SAFOP = safe operations (analysis)

LINEREMOVALCHECKSHEET