Produced Water Legislation

Under the terms of an international convention which takes into account the need to safeguard the marine environment, the permitted level of oil in produced water that can be discharged from an installation is 40 ppm, averaged over a month.  Regular scientific reviews have concluded environmental impacts are insignificant from discharges at these concentrations.  Anything above 100ppm must be reported as an oil spill. Operators must analyse the oil-in-water level twice each day and report the results to the regulatory authorities.

A 40mg/l target for oil-in-produced-water was first introduced by the Paris Convention in 1974, becoming an OSPAR (Oslo-Paris) standard in 1992.  This was implemented in the UK through the Prevention of Oil Pollution Act 1971.  In 1998 UKOOA member companies made a commitment to achieve 30mg/l company annual average oil-in-produced-water. 

OSPAR agreed Recommendation 2001/1 'Management of Produced Water from Offshore Installations' in pursuit of reducing pollution of the maritime area.  The overall goal of the recommendation is to:

Reduce the input of oil and other substances into the sea resulting from produced water, with the ultimate aim of eliminating pollution from those sources

• Ensure that an integrated approach is adopted, so that reduction is not achieved in a way that causes pollution in other areas
• Ensure that effort is made to give priority to actions related to the most harmful components of produced water

To implement these goals, each Contracting Party, which includes the UK, is to ensure that:

• The total quantity of oil-in-produced-water discharged to the sea in 2006, from all offshore installations under their jurisdiction, has been reduced by a minimum of 15% compared to 2000
• By the end of the year 2006 no individual offshore installation exceeds 30mg/l for oil-in- produced-water discharged to the sea
• From 1st January 2002, plans to construct new offshore installations should minimise such discharges and, where appropriate, achieve zero discharges

The reduction in the discharge of produced water effectively required a 28% reduction in total water discharged to sea, given the continuing trend of increasing water production since the 2001 recommendation was made.  It is also proposed that all new installations achieve zero discharges of oil in produced water to sea.  This may be problematic to implement and will act as an impediment on new developments given most are subsea tiebacks and rely on the use of existing processing facilities.  It is also questionable whether a zero discharge has an environmental benefit.  Also, one of the methods of achieving the reduction has been to increase the use of chemicals which also brings its own environmental issues, in both the creation and disposal of the material.  Some facilities are re-injecting produced water but care needs to be taken to ensure the environmental balance is correct as this increases the energy consumed and results in increased atmospheric emissions.

Independent research indicates that produced water’s contribution to the total volume of oil entering the North Sea is around 6%. 

Regulations are in place as part of the Oil Pollution Prevention and Control Regulations.  Every installation discharging produced water has been issued with a permit addressing the 15% reduction, including provisions for new entrants.  The regulations include a trading mechanism through which installations should be able to work together to meet the UK wide target.  The regulations also contain a substantial civil penalty, currently set at £108 for every kilo of oil discharged in excess of that permitted.  This was reduced from £280 for every kilo in excess following Oil & Gas UK analysis of abatement costs.

A large variety of techniques are already employed to remove oil from produced water and it has to be recognised that further abatement measures come with an environmental as well as a financial cost.  These costs should be compared with the incremental environmental benefit.  The Policy Studies Institute has examined the overall environmental impact from further abatement of produced water and made an overall impact assessment.  The study concludes that current levels of emissions suggest only a hypothetical or low risk; it must be questioned, therefore, whether the substantial new investments will deliver environmental value for money and will provide the most appropriate environmental effects.

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