By opening parts of the Atlantic and the Gulf of Mexico to oil drilling, the Obama administration wants to tap a huge energy resource that could keep fuel costs in check.

But don't expect gasoline pump prices to fall anytime soon because of the new drilling.

The offshore areas are located along relatively pristine parts of the U.S. Outer Continental Shelf, a new frontier for oil companies. It could take years before drillers will know how much oil can be pumped from these areas, and when.

A report by the federal Minerals Management Service noted that most of the seismic data used to evaluate oil and natural gas resources there are more than 25 years old. So the information "may not be adequate" to build maps or develop leases for drilling operations.

Where will companies be allowed to drill?
President Obama said Wednesday he'll push for opening offshore areas in the Gulf of Mexico and off the mid and southern Atlantic coast. Oil and g as resources would be developed about 50 miles off the Virginia coast and more than 125 miles from Florida's coast in the eastern Gulf of Mexico. The government also will allow oil exploration in the Arctic Ocean. The President doesn't support drilling at Bristol Bay in Alaska because of environmental concerns. He said proposed leases in that area would be canceled.

It's always tough to say exactly how much oil and gas lies under the ocean. But if drillers are able to tap as much as the government estimates, they could pump enough to cover a 15-year supply of oil and a 23-year supply of natural gas for the nation.

In the Gulf, there's anywhere from 36 billion to 41.5 billion barrels of undiscovered, recoverable oil and 161 trillion to 207 trillion cubic feet of undiscovered natural gas, according to the Minerals Management Service.

There's another 39 billion to 63 billion barrels of oil and 168 trillion to 294 trillion cubic feet of natural gas in eight planning areas in the Arctic and Atlantic oceans that are under consideration for leases between 2012 and 2017.

When will drilling begin, and when will we see oil flowing to U.S. refineries?
Exploratory drilling could begin as early as this summer in the Chukchi and Beaufort seas in the Arctic. That is only for a preliminary study to determine if those areas are suitable for future leases. Elsewhere, the Department of the Interior plans to hold sales for leases in the Gulf of Mexico, off the Virginia coast and in the Cook Inlet in Alaska by 2012.

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