Environment Report 2016

Mass of Chemicals Discharged In 2015, just over 102,500 tonnes of chemicals were discharged to the marine environment (around 170 tonnes per million boe produced), of which almost 72 per cent (73,500 tonnes) were from drilling activities. This is compared with 105,500 tonnes of chemicals discharged in 2014, of which 73 per cent were from drilling activity. While the total amount of chemicals discharged is consistently dominated by drilling chemicals, the amount of drilling chemicals released has fallen by over 30 per cent since 2000 (see Figure 4). Furthermore, coinciding with the long-term reduction in drilling activity, there has been a net decrease of almost 39,000 tonnes in drilling chemicals discharged since a peak in 2008. The increase in 2013 is due to more complex wells being drilled and is out of step with the general downward trend. Specialist chemicals are used in the production of oil and gas to maintain equipment integrity and optimise production. These chemicals include demulsifiers to improve oil separation from water; corrosion inhibitors to protect equipment; scale inhibitors to slow down scale build-up in pipework and valves; and biocides to reduce marine growth on equipment. Since 2011, the amount of production chemicals discharged has varied with production, having decreased, plateaued, and then started to increase in 2015. Last year, 28,500 tonnes of production chemicals were discharged representing an 8 per cent increase on 2014. Pipeline chemicals are used for pipeline maintenance and include biocides and oxygen scavengers. 2014 saw eight pipelines contribute to the ten largest discharges, all of which were either new or undergoing major repair works. Following completion of these works, 2015 figures show that pipeline chemical use has returned to a level consistent with recent years and discharges are at their lowest level since 2012.

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Figure 4: Production, Drilling and Pipeline Chemicals Discharged

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Drilling Chemicals

Production Chemicals

Pipeline Chemicals

Production

1,000 1,200 1,400 1,600 1,800 2,000

120,000

8

100,000

80,000

60,000

0 200 400 600 800

40,000

Production (Million boe)

Chemicals Discharged (Tonnes)

20,000

0

2000

2001

2002

2003

2004

2005

2006

2007

2008

2009

2010

2011

2012

2013

2014

2015

Source: EEMS July 2016

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