Environment Report 2015

ENVIRONMENT REPORT 2015

3. Emissions and Discharges Offshore 3.1 Introduction

Production on the UKCS peaked in 2000 at 1,719 million barrels of oil equivalent (boe) and has been declining since. In 2014, just over 545 million boe were produced 2 , 0.2 per cent lower than in the previous year. As a mature basin, the UKCS has to meet several challenges, including how to continuously improve environmental performance and efficiency as production of oil and gas becomes more technically difficult. This chapter highlights that, in general, emissions and discharges across the UKCS are falling even as production demands more energy intensive techniques. A comparison with Norwegian 3 and international 4 data from 2013 is also provided where available. 3.2 Produced Water Produced water is water that comes to the surface with hydrocarbons during production, either naturally from the reservoir or after injection into the reservoir to displace oil and lift it to the surface. The water is separated from oil and gas during the first stages of processing on the installation and discharged to sea after treatment to minimise the impact on the marine environment. Approval for produced water discharge is gained by applying for an oil discharge permit through the DECC UK Oil Portal 5 under the Offshore Petroleum Activities (Oil Pollution Prevention and Control) Regulations 2005. Produced Water Volumes The total amount of produced water handled on the UKCS remains comparable year-on-year from 2010 to 2014 despite an overall decline in hydrocarbon production. This is because, in a mature basin, as hydrocarbons become harder to reach and extract, larger volumes of water are produced. In 2014, produced water at 188 million cubic metres accounted for 88 per cent of the total well stream fluids 6 . Nonetheless, since 2000, there has been a net 40 per cent decrease in the volume of produced water actually discharged to sea from 263 million cubic metres to 157 million cubic metres (see Figure 1 opposite). This indicates that careful management measures and the Best Available Techniques are being implemented to minimise discharge.

2 This data come from the DECC Energy Trends bulletin: www.gov.uk/government/collections/energy-trends 3 The Norske Olje & Gass 2014 Environmental Report is available to download at www.norskoljeoggass.no/en/Publica/Environmental-reports/Environmental-report-2014/ 4 The International Association of Oil & Gas Producers (IOGP) Environmental Performance Indicators – 2013 Data is available to download at www.iogp.org/pubs/2013e.pdf 5 The UK Oil Portal allows operators to apply for and receive consents and permits. See https://itportal.decc.gov.uk/eng/fox/live/PORTAL_LOGIN/login 6 A term used to describe the total mass of fluids moving through the production systems. This includes produced water and oil in produced water; the produced water and oil reinjected; the total hydrocarbons produced (gas, oil and condensate); and the total fuel gas use and gas flared. Source for all these variables is EEMS data.

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