barrels blue barrels wiki barrels English barrels http://en.wikipedia.org/wiki/Barrel_(volume)#Oil_barrel barrels barrels blue barrels Wikipedia lists an oil barrel as 55 US gallons barrels barrels barrels http://en.wikipedia.org/wiki/Barrel_(volume)#Oil_barrel http://en.wikipedia.org/wiki/Barrel_(volume) Barrel_(volume) barrels Petroleum barrel barrel