Decommissioning Insight 2016 - Oil & Gas UK

DECOMMISSIONING INSIGHT REPORT 2016

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

2,000

180

Trunklines Other Pipelines Umbilicals Number of Pipelines (inc Umbilicals)

Increased Uncertainty in Forecasts

1,800

160

1,600

140

1,400

120

1,200

100

1,000

80

800

Total Length (km)

60

Number of Pipelines

600

40

400

20

200

0

0

2016 2017 2018 2019 2020 2021 2022 2023 2024 2025

Source: Oil & Gas UK

18 Trunklines are pipelines with a diameter greater than 14 inches and a length in excess of 18 kilometres. Umbilicals are utility support pipelines.

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