First of all, the European economy has to face a debt escalation again, which made the US dollar stronger. Since the currency of the crude oil means the US dollar, the changes of it always impact the prices of these resources.
The weather also plays an important role. Tropic storms still endanger the South coast and the Gulf of Mexico. After the Lee storm 15% of the US crude production is being closed, and it seems like it will stay this way.
After all these international and natural influencing factors, even the US economical politics can't solve their own problems. Obama job market program didn't inspired confidence in the traders.