A new method for reducing hazardous waste has been adopted on Statoil's Åsgard development in the Norwegian Sea.
This filtration system reduces the oil content in oily slop water below the ceiling of 40 milligrams per litre set by the Norwegian Pollution Control Authority for discharging such waste to the sea.
As a result, oily slops will no longer need to be sent ashore from drilling rigs for treatment as hazardous waste.
Shipping this waste water to land from Åsgard has previously incurred a destruction cost of roughly NOK 5,000 per cubic metre.
The saving with the new system comes to about NOK 2.5 million for an average Åsgard well, which generates roughly 700 cubic metres of slops from the completion process.
This cost reduction adds up to a considerable sum on a field which will be completing about 60 wells before 2003, says Jorunn Klovning, manager for health, the environment and safety in the resource development department of the Åsgard organisation.
Another advantage of the new technique is that brine recovered from the processed liquid can be reused.
Devised by Tetra Technologies Norge, a completion fluid supplier, this method is still under development.