Statoil Reduces Harmful Discharges from Heidrun

Harmful discharges to the sea from the Heidrun platform in the Norwegian Sea will be reduced by 95 percent with the help of new equipment for water treatment. The licensees in the Heidrun field are investing NOK 1.2 billion in upgrades that will result in environmental gains and improved recovery. During winter the work will include the installation of new equipment on the Statoil platform for the reinjection of produced water.

One year of testing has shown very promising results with regard to discharges to the sea. Emissions to the air are not increasing either, reports Sten Paltiel, adviser for the external environment on the Heidrun field. The produced water that is injected will provide pressure support in the reservoir. Seawater is also injected for the same reason. The Heidrun platform is also the first installation on the Norwegian continental shelf to be equipped with facilities for the removal of sulfates from the seawater. Mr. Paltiel explains that the substance barium, which is present in high concentrations in the Heidrun reservoir, reacts with the sulfate in the seawater. "By injecting sulfate-free seawater we can keep the wells open, thereby reducing the need for chemical-intensive well maintenance. This provides both environmental and financial gains."

The water projects mean that estimated recoverable reserves from the Heidrun field can be increased by about 100 million barrels of oil. Eli Aamot, Statoil's vice president for the environment, believes that the upgrade program on Heidrun is an important contribution in helping Statoil reach its objective of zero harmful discharges and emissions. "These measures are good examples of our achievements in environmental gains through the development and implementation of new technology," says Ms. Aamot.

The Heidrun field currently produces about 50,000 barrels of water per day. By 2010 this volume will have almost quadrupled. The field continues to produce at plateau level, which is around 180,000 barrels of oil per day.