US lifts world natgas resource estimate, cuts oil
* New assessment includes gas-rich areas in Arctic, Africa
* Estimates do not assess shale oil and gas, oil sands
WASHINGTON, April 18 (Reuters) - Regions outside of the United States hold 20 percent more untapped conventional natural gas and about 13 percent less oil than previously estimated, according to a U.S. government report released on Wed nesday.
In its latest world petroleum assessment, the U.S. Geological Survey estimated that about 5,606 trillion cubic feet of technically recoverable conventional natural gas is still undiscovered around the world, excluding the United States.
That's up from the 4,669 tcf estimated by the government in 2000. Much of that increase was due to the inclusion of the gas-rich areas Arctic and the basins of East Africa in the new survey, the agency said.
The USGS lowered its estimate of untapped world oil resources to 565 billion barrels, down from 649 billion barrels in the 2000 report.
"That's telling us something about how plentiful gas is likely to be in the future relative to oil and that is something we might want to take into account in our future energy mix," USGS Director Marcia McNutt said on a conference call.
The agency's projections included only oil and gas that could potentially be produced using existing technology and industry practices. The assessment did not take into account economic feasability and did not include unconventional fuel sources such as shale oil and gas and oil sands.
Advances in drilling techology have allowed drillers to develop vast shale oil and gas deposits in the United States, dramatically raising U.S. oil and gas output. (Editing by David Gregorio)