The largest force towards reserve growth in the present day comes from economic incentives. It simply was not attractive to recover hydrocarbons from certain fields at the price level we averaged from the late 80s to the early 90s. Today, with oil most likely going to hover between $50 and $70, that allows a much larger range of hydrocarbon utilization, both conventional and unconventional. At some point in the future, the unconventional sources will be the new conventional.

Mooooo!