Crude oil prices sold off heavily on Wednesday and Thursday, with front-month Brent futures falling more than 7 percent to the lowest level more two and half months.
Prices slumped amid growing concerns about continued oversupply in the market, the build up of inventories and the possibility of storage space running on land and forcing more oil to be stored expensively at sea.
The American Petroleum Institute reported on Tuesday that crude oil stocks in the United States rose by an unusually large 6.3 million barrels last week.
The Energy Information Administration confirmed on Thursday a build of 4.2 million barrels with inventories now 109 million barrels above the prior-year level.
There was plenty of other bearish fundamental news around, with OPEC predicting the oil market would remain oversupplied in 2016.
But prices have also been influenced by more technical factors, among them the expiry of the December Brent futures contract today which tends to reduce liquidity and exaggerate price movements.
