Oil & Gas UK Decommissioning Insight 2014

DECOMMISSIONING INSIGHT 2014

Subsea Infrastructure Decommissioning on the UK Continental Shelf

The years of high subsea infrastructure decommissioning activity in the CNS and NNS areas are from 2019 to 2022, while in the SNS and IS they are from 2016 to 2020. The decommissioning of mattresses and removal of other subsea infrastructure typically occur in the same year (see figure 17 and 18). Mattresses are usually removed from the seabed at decommissioning although they can be decommissioned in situ if badly degraded and approval has been obtained from the Department of Energy & Climate Change (DECC). Other subsea infrastructure includes manifolds, christmas trees, risers, spools, jumpers, anchors and subsea isolation valves (SSIVs). Pipelines are discussed in section 6.4. Due to the inclusion of additional subsea projects in the CNS and NNS areas in the 2014 survey, the number of mattresses and weight of subsea infrastructure have more than trebled the forecast in the 2013 report. Figure 17: Forecast of Mattress and other Subsea Infrastructure Decommissioning in the Central and Northern North Sea from 2014 to 2023

30,000

1,200

Increased Uncertainty in Forecasts

25,000

1,000

Increased Uncertainty in Forecasts

20,000

800

15,000

600

Removed

400

10,000

Number of Mattresses

200

5,000

Tonnage of Subsea Infrastructure to be

0

0

2014 2015 2016 2017 2018 2019 2020 2021 2022 2023

2014 2015 2016 2017 2018 2019 2020 2021 2022 2023

Source: Oil & Gas UK

Number/Weight 2014 to 2023

Total Expenditure 2014 to 2023

Mattresses and subsea infrastructure

-

£330 million

Mattresses

2,800

- -

Subsea infrastructure

54,100 tonnes

32