Conoco Completes Fifth Double-hulled Crude Oil Tanker

Journal Record, The (Oklahoma City), Apr 8, 1995

HOUSTON _ Conoco Inc. has completed and will soon place in service the fifth double-hulled crude oil tanker the company has built since its 1990 commitment to future construction of only double-hulled tankers.

The "Heidrun," the largest of Conoco's double-hulled tankers, will be used by its Norwegian affiliate to transport crude oil from the Heidrun Field in the Norwegian Sea. It is one of three diesel-electric powered shuttle tankers that will be employed in the Heidrun field, a joint venture with Conoco, Statoil, the Norwegian national oil company, and others. The Heidrun Field is scheduled to come onstream later this year.

The tankers use technologies such as diesel-electric power and bottom loading systems not normally found on crude oil tankers.

"The hostile Norwegian Sea conditions in which the `Heidrun' will operate present some unique challenges which we were able to meet by using proven technology in a new way," said E.L. (Rick) Oshlo, Conoco vice president of crude oil supply and trading-materials and services.

The Heidrun platform will be located in open water that is 1,148 feet deep and will use a subsea delivery system to transfer oil from the platform to the shuttle tankers. The water depth makes any mooring system impractical, requiring the "Heidrun" to have exceptional maneuvering and station-holding capability even in heavy seas, he said.

"We are using electric-powered bow and stern thrusters because their quick response to commands give us precise maneuvering and positioning capability," said Oshlo. "Since the thrusters required a lot of electrical power, only a relatively small increase in generation capacity was needed to electrify the main propulsion system, increasing the vessel's response to commands and its maneuverability," he said.