USGS Updates 2000 Estimates Of Undiscovered, Conventional Oil, Gas
With the latest estimate released April 18, world resources of undiscovered, technically recoverable, conventional resources are estimated at 565 billion barrels of oil; 5,606 trillion cubic feet (Tcf) of natural gas; and 167 billion barrels of natural gas liquids (NGL).
These new estimates are for conventional oil and gas resources only. Unconventional oil and gas resources, such as shale gas, tight oil, tight gas, coalbed gas, heavy oil and oil sands, may be significant around the world, but are not included in these numbers.
A fact sheet is available. http://pubs.usgs.gov/fs/2012/3042/