One of the reason (probably the main reason) for the recent pullback in crude oil prices is the uptick in the U.S. dollar. The chart at the link below shows how the U.S. dollar is valued compared to a basket of other currencies. There is a inverse relationship between the U.S. dollar and the price of oil because oil trades in U.S. dollars all over the world. BTW this relationship is EXTREMELY IMPORTANT to the stability of the U.S. dollar.
http://www.marketwatch.com/investing/index/dxy/charts
All of the nonsense with Greece is causing a dip in the Euro, so the U.S. dollar goes up. The Greek economy is 1/6th the size of the Texas economy.
From mid-2014 until today, AT LEAST $20/bbl of the dip in the oil price can be blamed on the rise in the U.S. dollar.