Environment Report 2016

The 2010 production systems and related equipment proportion (73 per cent of the total mass) is notable as it was dominated by eight releases of more than ten tonnes each. The largest of these was a release of 136 tonnes of a low hazard production control fluid due to the failure of a seal on a subsea template valve. This is the worst case release amount and contributes to the relatively large (26 per cent) contribution of seal failure to the causes of incidents in 2010. Other notable releases were in 2012 when 364 tonnes of oil-based fluid were released following a wellbore loss of containment and, in a separate incident, 139 tonnes of water-based fluid were released from a wellbore. In 2013, there were two large releases from hydraulic systems, one of 54 tonnes of a low hazard hydraulic fluid and one of 189 tonnes of monoethylene glycol, which is designated PLONOR. These masses are the worst case estimations for each incident and so the actual amount released is likely to be less. The graph also shows clearly the significant impact on total mass for each year that the individual large events have.

1

2

3

4

Figure 32: Accidental Chemical Release Mass by Source

350

1,000

Hydraulic Systems

5

900

Subsea Systems and Related Equipment

300

800

Pipework Infrastructure

250

700

6

600

Containers

200

500

Bulk Transfer Systems

150

400

7

Drainage Systems

Number of Releases

300

100

200

Production Systems and Related Equipment

50

8

Accidental Chemical Release Mass (Tonnes)

100

Other*

0

0

2010

2011

2012

2013

2014

2015

Number of Releases

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

Source: BEIS July 2016

47