To the doom sayer:
The evidence is in something called oil sands (also called oil shale), a tar-like substance that can be surface mined as coal often is. The oil is then separated from the dirt using energy from oil or natural gas extracted from the site itself to produce a tar-like goo called bitumen. It's then chemically split to produce crude as light as from a well head.
Oil sands in a single Venezuelan deposit contain an estimated 1.8 trillion barrels of petroleum, with 1.7 trillion in a single Canadian deposit. In all, about 70 countries (including the U.S.), have oil sand deposits although technology hasn't yet made them economical for exploitation. Of Canada's reserves alone, about 255 billion barrels (almost equal to the entire proved oil reserves of Saudi Arabia) is currently considered recoverable. And recovering it they are.