The trouble is we are slowly but surely moving towards the 1:1 factor whereby it takes the same amount of energy to extract a barrel of oil as is used by the extracted/processed product.
We use, or should i say current demand according to OPEC is ~85.21 Million barrels per day (around a quarter of this is used by America), this is nearly 1 Million more than last year and as it is becoming harder and harder to find and recover (the days of easy oil are nearly over) other sources are going to have to become a viable alternative.
Saudi Arabia still has a hell of a lot of the stuff but they are pumping seawater into the fields to keep the pressure up at the well heads, this is having a detrimental effect on the usable oil left.
IMO we need to explore ways of using coal/gas to liquid in a far more economical way than at present, there is still plenty of coal and gas in the ground and the majority of it is in pretty stable regions.
The reliance on oil as our major energy source is not going to last forever, suitable alternatives need to be found.
This is quite a good read for anyone interested in this subject:
http://www.sciencedaily.com/releases...0324225511.htm