Environment Report 2014

ENVIRONMENT REPORT 2014

3.4.1 Volumes of Cuttings Discharged The majority of cuttings discharged to sea from the UKCS are generated by drilling activities that use water-based drilling fluids. These fluids are labelled gold or silver under the CEFAS OCNS scheme, considered to have the lowest hazard to the marine environment. In 2013, 54,000 tonnes of cuttings separated from water-based fluids were discharged to sea. Meanwhile, 5,000 tonnes of cuttings from non-aqueous drilling fluids were discharged to sea after they had been treated to remove any residual oil to less than one per cent of the total volume. As mentioned, a permit must be sought from DECC before any such discharges.

The bulk of non-aqueous fluid cuttings (more than 40,000 tonnes) were brought to shore (see section 3.6) and 11,000 tonnes were injected back into the rock strata.

Figure 6: Drill Cuttings Discharges on the UK Continental Shelf from 2010 to 2013

70,000

Non-Aqueous Fluids

Water-Based Fluids

60,000

50,000

40,000

30,000

Tonnes

20,000

10,000

0

2010

2011

2012

2013

Source: EEMS June 2014

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