Oil edged further below $57 a barrel on Friday, pressured by evidence of ample supplies, including the biggest jump in U.S. inventories since 2001 and Saudi Arabian output reaching a record high.
Brent crude LCOc1 slipped 13 cents to close at $56.44 a barrel while U.S. crude CLc1 was down 43 cents at $50.36.
“Most of the fundamental factors are still pointing to lower prices,” said Eugen Weinberg, analyst at Commerzbank.
“At the moment, we have an oversupply of more than 1 million barrels per day.”
The price of Brent has halved from $115 a barrel in June last year, a drop that deepened after OPEC refused to cut output, choosing to defend market share instead.
Top exporter Saudi Arabia was the driving force behind the policy shift.
While some OPEC members are urging output cuts to boost prices, Saudi Arabia has shown no sign of a rethink.
Oil Minister Ali al-Naimi told reporters on Tuesday that Riyadh has boosted its crude production to 10.3 million bpd, the highest rate on record.
Further pressuring prices, a U.S. government report on Wednesday said domestic crude stocks surged nearly 11 million barrels last week, the biggest gain in 14 years.
A glut of unsold Nigerian crude is building up too, traders say.
This is particularly bearish for Brent, because Nigerian crude is priced against it.