Report reassesses drilling availability

About half the oil and more than a quarter of the natural gas beneath 99 million acres of federal land are off-limits to drilling, the Bush administration said Tuesday.

In a report sought by industry and ordered last year by Congress, the Interior Department’s Bureau of Land Management said just 3 percent of the oil and 13 percent of the gas under federal land was accessible under standard lease terms that required only basic protections for the environment and cultural resources.

An additional 46 percent of the oil and 60 percent of the gas ”may be developed subject to additional restrictions” such as bans to protect animals and sensitive terrain during parts of the year.

The revised inventory in the report is starkly different from that in a study done three years ago. That version, which covered 59 million acres in the Rocky Mountains, estimated that more than 80 percent of oil and gas was accessible, although in some cases subject to restrictions.

Energy companies disliked the earlier inventory because, they argued, it suggested more oil and gas was accessible, even when restrictions made drilling difficult or impossible. They lobbied Congress to force a change in the way the inventory was taken.

Language was inserted into energy legislation last year.

The Bureau of Land Management was required to include a much larger amount of land, while excluding from the inventory lease areas where drilling already was under way. The agency also was directed to take into account seasonal drilling bans to protect animal habitat, and to consider such leases as significantly restricted.

All these changes reduced the percentage of oil and gas resources that can be viewed as open for development.

The new inventory covers 99 million acres ”” 40 million more than the 2003 report ”” from Alaska to the Appalachian Mountains. The area is estimated to hold 187 trillion cubic feet of natural gas and 21 billion barrels of oil, or 76 percent of onshore federal oil and gas resources.

The amount of oil considered accessible without limits declined by about two-thirds, from 2.2 billion barrels to 743 million barrels, under the new inventory. Accessible natural gas was cut by about the same proportion, from 87 trillion cubic feet to 25 trillion cubic feet.

The United States imports about 12.4 million barrels of oil a day and uses about 21 million. It produces about 20 trillion cubic feet of natural gas annually.

The Arctic National Wildlife Refuge in Alaska, which is off-limits to drilling and was included in the survey, is thought to have about 10.4 billion barrels of oil, while Prudhoe Bay, the country’s largest oil field, has produced more than 10 billion barrels since 1977.

Examined for the first time are three oil and gas basins in the Southeast and the Appalachian Mountains and a basin in northern Alaska, including the Arctic refuge, which is thought to have the largest untapped U.S. oil field ”” one where leasing is not allowed.

By omitting federal land already being drilled without access restrictions, the inventory reduced the amount of resources considered accessible by 5 percent.

Bureau director Kathleen Clarke called the new inventory ”a more complete and accurate picture” and a ”helpful tool as we consider the road forward and the needs of the growing nation.”

Environmentalists said the new study gave an impression that more land was closed to energy development than really was the case.