Yahoo Finance

Refiners, which convert crude into gasoline and other products, are affected by the larger supply-demand picture for oil, but they’re more dependent on the balance between the price of oil and the fuels they make. Currently, the supply of crude oil is rising because OPEC has been increasing crude production in a bid to gain market share, but the supply of fuels isn’t rising as much. There simply aren’t enough refineries to turn all that crude into gasoline and diesel.