Discharge of produced water and chemicals is now a thing of the past at the Oseberg Field Center in the North Sea. Hydro and its partners have invested NOK 270 million on injecting and storing the discharge in the Utsira sandstone formation, 1,000 metres beneath the sea bed.
The environmental measure, which was implemented at Oseberg on 2 March, is part of Hydro's efforts to achieve zero environmentally damaging discharge to the sea from the installations on the Norwegian continental shelf.
"It is important for Hydro to keep its promise to eliminate environmentally damaging discharge into the sea, and this is an extremely effective measure," says Jan Arve Haugan, Senior Vice President for Oseberg-Grane.
The cost of Hydro's action plan to reach this target - which the Norwegian authorities and operator companies on the Norwegian continental shelf have agreed to achieve in 2006 - is NOK 430 million.
In addition to the injection implemented at Oseberg, Hydro has invested in comprehensive purifying measures on the Troll field, in order to achieve the goal of zero environmentally damaging discharge.
Effective measure
Every day Oseberg Field Center processes around 200,000 barrels of oil, including production from the fields Tune, Oseberg East, Oseberg South, Oseberg C and Vestflanken. In addition the gas export facility has a capacity of 30 million cubic metres per day.
The amount of produced water and chemicals from the field has gradually increased to around 40,000 barrels per 24-hour period, and this will rise further to a level of around 125,000 barrels as the fields age.
Up to now, produced water and production chemicals have been discharged into the sea, having been separated in the processing plant. When the new environmental well is put into use, the discharge will be pumped down into the extensive Utsira formation. In addition, chemical consumption on the platform is significantly reduced.
The environmental investment at Oseberg is comprised of two elements: a new injection well, and equipment to pump produced water and chemicals underground.
Significant environmental gains
Most injection wells are drilled into a reservoir in order to provide pressure support to production. This well has no connection to the reservoir, but is to be used exclusively in the context of depositing the produced water.
"The environmental improvement brought about by this well will be significant - this is perhaps our best ever environmental initiative, measured in terms of the investments made," says Ståle Teigen, manager of HSE Environment in Hydro's Operations sector.
"Tests we have carried out show that the water injected into the Utsira formation will neither leak out again onto the sea bed, nor pollute water we collect from the formation for injection into other fields. This must mean that we can call this an extremely successful environmental project," says Teigen.