"According to the United States Geological Survey, the Orinoco Belt alone is estimated to contain 900–1,400 billion barrels (2.2×1011 m3) of heavy crude in proven and unproven deposits. Of this, the United States Geological Survey estimated that 380–652 billion barrels (1.037×1011 m3) could be technically recoverable, which would make Venezuela's total recoverable reserves (proven and unproven) among the largest in the world.  The technology needed to recover ultra-heavy crude oil, such as in most of the Orinoco Belt, may be much more complex and expensive than that of Saudi Arabia's light oil industry. The USGS did not make any attempt to determine how much oil in the Orinoco Belt is economically recoverable."

As pointed out elsewhere by others,  "economically recoverable" is not cast in stone in perpetuity. 

All that oil that has been "fracked" in the last few years wasn't  "economically recoverable" just a few years ago.

"Geology" from you or from the USGS?  Sorry.  You lose!