The U.S. Energy Information Agency has released the annual Energy Outlook 2012.
The EIA says:
The Annual Energy Outlook 2012 (AEO2012) presents three alternative paths for world oil prices based on different production and economic assumptions. Among these cases, the real (constant 2010 dollars) oil price in 2035 ranges from $62 per barrel in the Low Oil Price case to $200 per barrel in the High Oil Price case, with the Reference case at $145 per barrel.
Read the E.I.A. release here