The big elephant in the room is the unlocking of unconventional(called shale oil) is big, but the shale gas is far, far greater.
Why? there is much much more shale gas in the ground, and shale gas moves a heckuva lot easier than oil through these very low permeability formations.
Result? multiply that projection of years of natural gas by 10 or 100.
What was unconventional is now conventional the key is money and at what point do you make it. We go back to Monty Hall and The Price is Right!