The agency also upped its projection of shale gas reserves to 7299 Trillion cubic feet, up 10% from 2011.
The report covered 41 countries, 95 basins and 137 formations.
The last global estimate in 2011 pointed to 6600 Tcf of gas. It did not issue a 2011 global estimate for shale oil.
The agency cautioned, however, that geology does not tell the whole story, with challenges in logistics in remote locations, governance concerns and public opposition posing sometimes formidable obstacles to developing the reserves.
“Recent experience with shale gas in the United States and other countries suggests that economic recoverability can be significantly influenced by above-the-ground factors as well as by geology,” the EIA wrote in the report.
Russia ranked as the country with the top shale oil reserves, with 75 billion barrels of technically recoverable reserves.
The US ranked second with 58 billion barrels, China with 32 billion barrels and Argentina with 27 billion barrels.
Rounding out the top 10 were Libya with 26 billion, Venezuela with 13 billion, Mexico with 13 billion, Pakistan with 9 billion barrels, Canada with 9 billion barrels and Indonesia with 8 billion barrels.
As far as shale gas reserves, China topped the list with 1115 Tcf. Argentina pulled ahead to second place with 802 Tcf, Algeria moved up to third with 707 Tcf and the US came in fourth with place with 665 Tcf.
Also in the top 10 were Canada with 573 Tcf, Mexico with 545 Tcf, Australia with 437 Tcf, South Africa at 390 Tcf, Russia with 285 Tcf and Brazil with 245 Tcf.
*Kathrine Schmidt, Upstreamonline