An increase in the amount of oil released to the North Sea in produced water has led some littoral countries and Non-Governmental Organisations to call for tightening the control measures on discharges. The E&P Industry has reviewed the recent information on the fate and effects of produced water discharge on the marine environment (more than 100 papers) as well as progress in handling produced water, including reinjection and shut off techniques.

There clearly has been a concerted research effort to provide greater understanding of the management of produced water. Nevertheless, there is much less new information than might have been expected. But even so, there is now a clearer understanding on the fate and effects of produced water. The composition and properties of produced waters discharged to the North Sea are now well established. Major improvements have been made in the determination of groups of organic substances such as volatile organic compounds (VOC), polycyclic aromatic hydrocarbons (PAH) and phenols, and robust methods for their determination are now available.

Discharge volumes and loads have stabilised and are expected to remain at the present level for around 5 years. Alternative management solutions are being researched and major advances in re-injection and shut-off techniques are expected in the next few years although they will take time to implement on a wide scale. The quality of discharged water has also remained stable with an oily content of around 30 mg.l−1 despite the rapid increase in the quantity of water treated offshore. Moreover, the other contaminants from discharges of produced water are not a major component of the total input of contaminants to the North Sea.

In terms of fate and effects of the discharges, greatest emphasis has been put on impacts arising from chronic exposures, including bioaccumulation and biomagnification. Recent focus on the effects of endocrine mimicking substances is being incorporated into research programmes.

In the second part of the paper, the assessment of the new measures that the Contracting Parties to the Oslo and Paris Convention envisage confirms the need for an integrated approach to produced water management, and shows that additional severe constraints on produced water discharges would have a negative impact on the E&P Industry without any net benefit for the marine environment

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