Steady supply and increasing demand, this coupled with any kind of instability in the marketplace will always cause prices to go up. Lets face facts as the worlds population goes up the demand for oil will continue to rise. The supply has already hit the top of the bell curve and we are sliding down the backside of"economicly availble rescource". Any oil we find now will be expensive to extract. Hence higher prices.
Unfortunatly prices fluctuate MUCH faster than wages.