Statoil Begins Preliminary Work on Snohvit Subsea System

Work has begun at Statoil on qualifying technology for the record-long umbilical which will link its Snohvit development in the Barents Sea with the land facilities in northern Norway.

"We expect to sign a contract this summer for the subsea system and umbilical," reports staff engineer Inge Polden in the Snohvit project. "This job will be awarded to one of three suppliers we have frame agreements with."

Statoil and the subsea system suppliers are now testing existing technology for the 160-kilometer bundle of control lines and cables. This verification will continue until the end of 2002.

All the wells planned for Snohvit – 21 for gas and condensate and one for carbon dioxide injection – will be remotely controlled from land through the umbilical. The distance involved requires a voltage of 3,000 volts – three times the conventional level for a subsea facility. With a diameter of roughly 11 centimeters, the umbilical will contain high-voltage power lines, fiber-optic cables and hydraulic piping. The fiber-optic cables will be used to transmit control signals to subsea valves and to return information from sensors mounted in the wells. Snohvit will involve the world's longest distance between the control station on land and the first subsea installation on the field. By comparison, the maximum umbilical length on Statoil's Asgard field in the Norwegian Sea is 50 kilometers. And the group's nearby Mikkel project will involve a span of 87 kilometers.

Plans call for Snohvit to be developed in three phases. When these have been completed in 2018, the longest distance over which remote control is exercised will be 210 kilometers.