Environment Report 2017

Releases by Source Understanding source trends for past data allows operators to develop plans to target operational areas where accidental releases have been more frequent. However, the limited information included in the PON1 database on the circumstances leading to releases means they are allocated to broad categories. In addition, the impact of individual high mass releases on the data makes trending difficult. Nonetheless, reviewing the aggregated data for the period 2010-16 does provide some indication of the trends. The majority (674 tonnes, 56 per cent) of the reported accidental oil releases between 2010 and 2016 came from production systems and related equipment; 631 tonnes (94 per cent) of this came from just three releases. In 2010, there was one spill of 131 tonnes of crude from a failed subsea sump pump; in 2012, 405 tonnes of condensate were released from a wellbore loss of containment; and, in 2016, 95 tonnes were released from the produced water system of a platform. These masses are the worst-case estimations for each incident and so the actual amount released is likely to be less.

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2

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The second largest category was pipework infrastructure (225 tonnes, 19 per cent), the majority of which was attributable to a single release in 2012 when 218 tonnes of crude were released from a pipeline.

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As stated above, most oil releases are very small and so large releases have been shaded in Figure 29 to be easily identified. The number of releases has stayed relatively stable over the period, averaging around 272 releases each year. As the graph shows, the mass released varies much more widely. The average yearly mass released for the period is 172 tonnes, but the range is between 24 tonnes in 2015 and 521 tonnes in 2012. The graph shows clearly that this variation is caused by the significant impact on total mass that individual large mass release incidents have.

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Figure 29: Accidental Oil Release Mass by Source

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600

350

Other*

300

8

500

Hydraulic Systems

)sennoT( ssaM esaeleR liO latnediccA

250

Subsea Systems and Related Equipment Pipework Infrastructure

400

9

200

300

Containment

150

Bulk Transfer Systems

10

200

Number of Releases

100

Drainage Systems

100

Production Systems and Related Equipment Number of Releases

50

11

0

0

2010 2011 2012 2013 2014 2015 2016

*Other includes releases from firefighting systems, flare systems, deck washings and unidentified sheen, as well as those releases for which no source is identified. Shading highlights single large spills in that particular category.

Source: BEIS July 2017, Oil & Gas UK

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