Decommissioning Insight 2015
7. Decommissioning Activity Forecast 2015 to 2024 The following sections focus on specific areas of decommissioning activity. 7.1 Well Plugging and Abandonment
The purpose of well P&A is to isolate the reservoir fluids within the wellbore and from the surface or seabed. This activity is carried out on the UKCS in accordance with industry guidelines 14 and legislation 15 and can be challenging. It may involve intervention; the removal of downhole equipment, such as production tubing and packers; and well-scale decontamination treatment. The process also requires the wellhead and conductor to be removed to three metres below the seabed. Well P&A is the largest component (46 per cent) of decommissioning expenditure in the UKCS over the next decade and is forecast to cost £7.7 billion in total over this period with 1,224 wells scheduled for P&A. This represents close to 30 per cent of the some 4,300 wells that will eventually require decommissioning in the basin. This survey covers three types of wells: platformwells; subsea development wells; and suspended subsea exploration and appraisal (E&A) wells. 7.1.1 The Central and Northern North Sea/West of Shetland Between 2015 and 2024, 950 wells are forecast to be plugged and abandoned in these regions. This is an increase of over 400 wells compared to the 2014 report, primarily due to the 41 new projects entering the survey in these regions, the majority of which are concentrated in the CNS. The rise in total forecast expenditure on well P&A in these regions by £1.5 billion to £6.2 billion is small in comparison to this growth in activity. This points to the relatively low expenditure forecasts for a number of the new projects as some of the wells will be simple P&As and are cheaper to perform. Deflated rig rates in the current climate may also be reflected in these expenditure forecasts. The majority of the increase in activity is concentrated towards the end of the survey timeframe, although there are additional wells in the nearer term. In 2021, 153 new wells are forecast to be plugged and abandoned. This peak is due to 27 fields scheduling well P&A at the same time. It is expected that this activity will smooth out as forecasts are revisited to balance the demand for vessels and personnel that carry out the work.
14 Guidelines on the Abandonment of Wells and Qualification of Materials for Abandonment are available to download at http://oilandgasuk.co.uk/product/op105 and http://oilandgasuk.co.uk/product/op109 15 See www.legislation.gov.uk/uksi/1996/913/made
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