BP begins drilling world’s longest wells off Alaska

British energy giant BP has started drilling the world’s longest wells to a hard-to-reach offshore reservoir in the Beaufort Sea, the company said Monday.

Buried beneath thousands of feet of rock on the outer continental shelf, the Liberty project has required major refinements in drilling technology, including well bores that pierce up to eight miles of shales and silt stone, BP executives said.

Liberty may portend a future of tougher oil extraction in Alaska, where production from Prudhoe Bay, America’s largest oil field, and its satellite reservoirs has been falling for two decades.

“All the easy development is done,” BP Alaska president Doug Suttles said.

“Cutting-edge technology is going to define the future of the industry in Arctic oil field engineering and development,” he said.

The reservoir, six miles off Alaska’s northern coast, is expected to yield about 100 million barrels of oil starting in 2011, BP executives say.

The $1.5 billion in development costs will include a specialized Arctic drilling rig and several spider-like well bores centered on a man-made concrete island.

Despite the opening of many small fields, such as Liberty, the amount of oil flowing through the trans-Alaska pipeline has fallen from a high of more than 2 million barrels a day in 1988 to 740,000 barrels a day last year, according to Alyeska Pipeline Service Co.

BP, based in London, operates several other offshore oil fields in the region, including Northstar and Endicott.