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ENVIRONMENT REPORT
2016
Figure 19: Concentration of Oil in Produced Water for each Operator by Hydrocarbon Type
0
5
10
15
20
25
30
35
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
Oil in Produced Water (mg/l)
Oil
Gas
Condensate
Industry Average 2015
Industry Average 2014
Limit = 30 mg/l
Source: EEMS July 2016
4.3 Discharged Drill Cuttings
Figure 20 opposite shows the distribution of drill cuttings discharged to sea across the operators on the UKCS in
2015. The amount discharged depends on the length of wells drilled – the longer the well, the more drill cuttings
produced. In 2015, almost 270 tonnes of cuttings were discharged per well drilled, which is slightly lower than in
2014 (280 tonnes per well drilled).
Last year, just five of the 33 operators in this category discharged treated oil-based fluid cuttings. Discharge of
untreated oil-based fluid cuttings is not permitted on the UKCS and so all of these assets have on-board systems
to clean any discharged cuttings to the permitted standard (less than 1 per cent oil content).
An increase from just under 9,000 tonnes of oil-based fluid cuttings discharged in 2014 to just over 10,000 tonnes
in 2015 indicates that more on-board cleaning is being carried out, reducing pressure on onshore waste treatment
and disposal options. Alternative routes for cuttings disposal include shipping to shore, injection and leaving in
the well.
Operators A to L are those that either carried out no drilling in 2015, or shipped all their cuttings to shore for
remediation and disposal.
Operators AG and AH carried out relatively large drilling campaigns in 2015 and, although the number of wells
drilled equates to less than 15 per cent of the total, the majority of wells were significantly longer than the industry
average, accounting for the high mass of drill cuttings.