It's a momentum feedback loop driven by the marginal fool...
If the cure for high inventories is low prices then why are inventories at an all time high despite oil prices at 2009 levels? Because of speculation and carry storage as opposed to final demand:
Inventories
And if the cure for low prices is increased demand, then why is the price so low while the long futures position is all time high? Again, purely due to speculation, which has only increased the amount of oil on the market.
Commitment of traders:
All of which means that oil has become 100% a momentum trade, that will end extremely spectacularly, once the last fool is found.
USO Volume indicates a low volume head fake
The long-term USO (ETF) chart indicates the colossal cost of carry losses incurred by speculators...
USO Spiked above the trend line and then gave it all back...