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Conoco Wednesday inaugurated the world's first floating oil platform,...

By
CATHY BOOTH

OFF THE SHETLAND ISLANDS, Scotland -- Conoco Wednesday inaugurated the world's first floating oil platform, a 47,400-ton steel highrise that drifts gently on the North Sea while pumping $2.25 million worth of oil a day.

The Hutton Tension Leg Platform, or TLP in oil platform lingo, lies 90 miles northeast of the Shetland Islands amid the biggest single concentration of producing oilfields in the North Sea.

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The TLP's nearest neighbor is just 20 miles away and clearly visible on good days, but the Hutton platform is unlike nearby oil platforms in that it has no massive underwater steel structure.

Instead, 16 steel tethers -- each just 10 inches in diameter - anchor the platform to the ocean floor.

In ceremonies Wednesday, Energy Secretary Peter Walker welcomed the 'North Sea's new baby,' which was developed over a decade at a cost of $1.25 billion as a prototype for future oil platforms which must pump in deeper and deeper waters to recover oil.

The revolutionary floating platform, which began pumping oil on Aug. 6, is currently producing in the range of 75,000 barrels of oil a day from eight wells.

Over the next 20 years, Conoco hopes to recover an estimated 200 million barrels of oil from 13 oil-producing wells off the TLP.

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Conoco's projects general manager, Tom Marr, said the floating TLP idea is not new. It was first considered during World War II for use off the U.S. west coast to guard against a possible Japanese invasion.

While the floating platform has been 15-20 percent more expensive than conventional platforms in the North Sea, he said Conoco is confident the design will pay off in the future by pumping oil in deeper and more difficult waters.

Although the Hutton TLP is pumping in just 485 feet of water now, Conoco claims it could pump in waters of 3,000 feet without difficulty and in 4,000 feet by 1986 -- a depth conventional platforms cannot hope to match.

Conoco, a subsidiary of Du Pont Co., is already working on a smaller, lighter, more affordable floating platform for the Gulf of Mexico.

Unlike conventional platforms, the TLP was built on dry land in Scotland, then towed 260 nautical miles in just three days by five tugs. Twenty-two days later, it was pumping oil -- the fastest completion from installation to startup in a major offshore project.

One major disappointment, however, has been a drop in pumping capacity because of a compression problem in one of the nine original wells. While the platform was pumping 95,000 barrels a day last summer, it is now down to just 75,000 barrels a day.

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For visitors and the 270 men currently living on the platform, the TLP is an odd sensation, thanks to its horizontal sway.

In gentle weather, the platform moves only about 1 yard -- enough to ruin a game of pool in the recreation room but barely noticeable. In the worst weather, however, it could move up to 20 yards.

Like a ship, the platform is naturally buoyant but it does not bob like a buoy thanks to the 16 steel mooring lines which are kept under constant tension. In addition, the platform's fat floating legs have a computerized ballast system to maintain stability.

Because the platform moves, the drilling rig itself must move and the well shaft is flexible. Visitors can actually touch the soft rubber tube through which the 100-degree oil pulses out into the Brent pipeline.

The other future benefit of the floating platform is the ease of removal. Current steel structures will have to be blasted out of the water as against the simple matter of cutting the TLP's steel tethers and towing it away.

The Hutton TLP is operated by Conoco on behalf of a group of eight partners, with Conoco, Britoil and Gulf Oil Corp. with a 20 percent share, Amoco Exploration Co. and Enterprise Oil at 10 percent, Mobil 8 percent, Amerada Hess 7 percent and Texas Eastern North Sea Inc. 4 percent.

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