Environment Report 2019
4.1 Dispersed Oil in Produced Water The average concentration of dispersed oil discharged to sea in produced water across industry increased by 5 per cent, from 15.3 mg/l in 2017 to 16.1 mg/l in 2018. Despite the increase, the average remains below OSPAR’s annual recommended limit of 30 mg/l. Average oil-in-water concentrations for individual operators are the result of several factors. Those operators with higher values may have more gas production or challenging reservoirs, for example. The operator benchmarking illustrated in Figure 25 below therefore provides a general picture of industry dispersed oil-in-water performance, but cannot be interpreted as some operators performing better than others. The large concentrations reported for two gas installations are the result of very small volumes of produced water discharged over a short time frame and do not represent sustain discharges at high oil concentrations. The total oil discharged by these two operators was less than one tonne.
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Figure 25: Concentration of Dispersed Oil in Produced Water per Operator by Hydrocarbon Type, 2018
140
Oil
2018 Industry Average 2017 Industry Average
Gas Mixed Production
120
60 )l/gm( retaW decudorP ni liO desrepsiD 80 100
40
20
0
A B C D E F G H I
J K L M N O P Q R S T U V W X Y Z AA BB CC DD EE FF GG HH
Source: EEMS, May 2019
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