Crude oil prices and oil stock prices

XOM is one of the stocks that I regularly follow. I have seen its ups and downs. I don't quite understand all the factors that affect its price. One of the things that intrigues me is the crude oil prices - which I also follow.

Question: If I don't consider other factors (such as the broad market conditions): if the crude oil price goes up, will XOM follow and goes up? Converselyly if crude oil price goes down, will XOM drop?

Why when crude oil came down from a peak of $140 a barrel to $40-$50, XOM still stand so tall? It only drop from $90 to now $80.

XOM is net buyer of crude so $147 crude is a heckuva strain on their fat wallet. It's incredible to see a half trillion dollar company move 10% and more in a day isn't it?

I watch USO (United States Oil ) :top:

I watch USO some but, mostly I play ETFs DIG and it's inverse DUG. They seem the be pretty predictable.

Thanks XOM (the poster). I didn't realize XOM (the company) is a net buyer of brude oil. I mistakenly thought they are the producer of oil.

But... the gasoline one pays at the pump follows the fluctuations of the crude oil prices. Wouldn't the profits at these oil companies be transparent? (They pass on the cost to the consumer.) I have been scratching my head on trying to figure out the relationship (if there is any)between crude oil prices and these oil company stock prices