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DECOMMISSIONING INSIGHT REPORT
2016
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5.2 Facilities and Pipelines Making Safe and Topside Preparation
For a platform or pipeline to be decommissioned, they must first be hydrocarbon free. This activity is referred to
as ‘making safe’ in the Oil & Gas UK Decommissioning Work Breakdown Structure and must be carried out in line
with environmental and safety considerations. ‘Making safe’ of facilities includes cleaning, freeing equipment of
hydrocarbons, disconnection and physical isolation, and waste management. ‘Making safe’ of pipelines involves
depressurising them and removing hydrocarbons. Then the pipelines are cleaned and purged, with the cleaning
programme based on the specific needs of the system. This may involve the use of pigs, which are maintenance
tools used to clean or inspect the insides of pipelines.
Pipeline ‘making safe’ is sometimes carried out alongside facilities ‘making safe’, particularly in the case of small
topside and pipeline tie-backs. In these cases, the same team and some of the same equipment can be used for
both activities. ‘Making safe’ can be carried out several years prior to removing a platform or decommissioning a
pipeline, leaving them hydrocarbon free until the next phase of decommissioning.
For facilities, the next phase involves separating the topsides and process and utilities modules and carrying out
appropriate engineering, such as the installation of lift points to prepare for removal. The topside preparation
required will depend on the removal method used.
Over 570 topside modules are forecast for ‘making safe’ on the UK and Norwegian Continental Shelves from 2016
to 2025. The greatest number of modules are located in the northern North Sea and west of Shetland (211) with
the least amount in the southern North Sea and Irish Sea (83).
Operators expect 600 topside modules to be prepared for removal. The forecast is slightly higher than that for
facilities ‘making safe’ as some projects have already carried out ‘making safe’ activity.
Over the next decade, close to 5,200 kilometres of pipeline are expected to be 'made safe'. Fifty-six per cent of
this activity is concentrated in the southern North Sea (2,885 kilometres), while only 7 per cent is forecast on the
Norwegian Continental Shelf (354 kilometres).