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DECOMMISSIONING INSIGHT REPORT
2016
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5.5 Pipeline Decommissioning
The extensive pipeline network in the North Sea measures in excess of 45,000 kilometres in total and is used to
deliver hydrocarbons to receiving facilities and end-users across Europe. This transportation network is of vital
importance when the economics of field-life extension projects and future development opportunities are being
assessed and it is therefore essential that major pipelines are not decommissioned prematurely. On the UKCS,
to achieve the objectives of the MER UK (maximising economic recovery from the UKCS) strategy, the deferral of
pipeline decommissioning to the end of field life, or for possible reuse, is sometimes carried out under the Interim
Pipeline Regime, whereby the regulator – the OGA – may request that the pipeline owner carries out ‘making safe’
activities and maintains the pipeline for possible future reuse.
There are rigid pipelines and flexible flowlines in the North Sea. Their diameters can vary between 2 and 44 inches.
Options for decommissioning include full removal, decommissioning
in situ
, trenching and burial. The approach
adopted will be based on comparative assessments of all the different options and consideration of safety and
environmental factors, technical feasibility, other sea users and cost. All decisions are made on a case-by-case
basis in consultation with key stakeholders and with regulatory approval.
Operators intend todecommissionaround17per cent of the total pipelinenetwork length fromtheUKandNorwegian
Continental Shelves over the next decade, close to 850 pipelines with a total length of almost 7,500 kilometres.
The central North Sea is the area where the greatest number of pipelines (484) is estimated to be decommissioned,
making up 57 per cent of the total. However, in terms of length to be decommissioned, the southern
North Sea and Irish Sea will see the greatest proportion at 3,426 kilometres or 46 per cent of the total
pipeline length to be decommissioned. On the Norwegian Continental Shelf, all the activity is planned in the
Norwegian North Sea.
It should also be noted that many of the larger projects lie towards the end of the survey timeframe and so the
associated pipeline decommissioning activity will occur beyond 2025.
Figure 25: Combined Pipeline Decommissioning Forecast for the UK and Norwegian Continental Shelves
18
0
20
40
60
80
100
120
140
160
180
0
200
400
600
800
1,000
1,200
1,400
1,600
1,800
2,000
2016 2017 2018 2019 2020 2021 2022 2023 2024 2025
Number of Pipelines
Total Length (km)
Trunklines
Other Pipelines
Umbilicals
Number of Pipelines (inc Umbilicals)
Source: Oil & Gas UK
Increased Uncertainty
in Forecasts
18
Trunklines are pipelines with a diameter greater than 14 inches and a length in excess of 18 kilometres. Umbilicals are
utility support pipelines.