More water injection for Heidrun

July 17, 2001, 09:00 CEST

The Heidrun licencees have resolved to continue a project to extend water injection on the Statoil-operated Norwegian Sea field.

Implementation is likely to be approved in October, when the principal contract for modifying the tension-leg platform should also be awarded.

Increased water injection is needed on Heidrun to ensure efficient oil recovery from the Lower Tilje and Åre reservoirs.

Plans call for more use of sea water and full-scale utilisation of produced water. The latter has been returned underground through a pilot well since 5 february.

"Injecting produced water is an important element in our zero-discharge strategy," says project manager Knut Gjertsen in Heidrun’s production and maintenance technology department.

"Getting this liquid back into the reservoir will give us a major environmental gain."

He says that the aim is to inject virtually all the produced water, which currently totals some 31,000 barrels per day and is set to rise to 187,500 daily barrels.

Plans call for 76 wells on the main Heidrun field. 26 producers are now operational, along with 10 injectors for seawater and one for gas.

Injected seawater contains a good deal of sulphate, which reacts with barium in the formation water to produce deposits which can block wells.

The new injection plant planned for Heidrun will accordingly incorporate a module to remove sulphate from the seawater before it is injected.

Also embracing a module with three powerful water injection pumps, the modifications are due to be completed in the autumn of 2003.