June 25 (Bloomberg) -- Expanded offshore drilling in the U.S. won't affect oil and natural-gas prices much, the head of the Energy Information Administration said.

Guy Caruso, speaking today at a press conference in Washington, said his agency had considered the effect of more drilling in a 2007 report. Higher energy prices this year might change the results, although the time needed for resource development would damp any outcome, he said.

``It does take a long time to develop those resources,'' Caruso said. ``Therefore the price impact is muted by that.''

President George W. Bush last week proposed expanded drilling in the Outer Continental Shelf and development of energy sources in Alaska's Arctic National Wildlife Refuge as a response to record prices. Crude-oil futures hit a record $139.89 a barrel on the New York Mercantile Exchange on June 16.

Senator John McCain of Arizona, the presumptive Republican presidential nominee, has expressed support for more drilling. His potential Democratic opponent, Senator Barack Obama of Illinois, opposes more drilling.

``The projections in the OCS access case indicate that access to the Pacific, Atlantic, and eastern Gulf regions would not have a significant impact on domestic crude oil and natural gas production or prices before 2030,'' the agency said in its 2007 report.

The Energy Information Administration is the statistical arm of the U.S. Energy Department.

To contact the reporter on this story: Tina Seeley in Washington at tseeley@bloomberg.net.

Last Updated: June 25, 2008 10:45 EDT