Originally Posted by http://www.newton.dep.anl.gov/askasci/eng99/eng99288.htm
A barrel of oil is 42 gallons.
The amount of gasoline that can be distilled from crude depends on where the
crude is obtained. Venezuelan crude yields little gasoline (about 5%),
whereas Texas or Arabian crude yields about 30% gasoline. This is called
"straight run" gasoline.
However, the distilled components of the crude oil can be further processed
into gasoline by various other methods (catalytic and thermal cracking,
hydrocracking, catalytic reforming, alkylation, and polymerization) to
yield even more gasoline.
Bob Erck