Questions
•What drove crude prices up in 2004?
•What caused the light-heavy crude price differences to change in the short run?
•What role did refinery capacity and heavy crude oil production play in 2004 light-heavy crude oil price differentials? 
•Are higher refinery margins going to continue in the future and what lies ahead for refinery capacity?
SAnother important price change in 2004 was the increase in light-heavy crude price differences that occurred.

SAs the data came in for 2004, the main driver behind this rapid increase was not what many analysts were postulating.