LONDON: Brent oil prices will tumble $31 per barrel by the end of the first quarter as global petroleum inventories continue to build, Bank of America Merrill Lynch analysts forecast on Thursday.

Analysts around the world are slashing forecasts for Brent and WTI crude in the wake of a slide of more than 50 percent since last June which has taken prices to near-six-year lows.

A fall to $31 per barrel would see Brent hit levels not seen since April 2004.

“First and foremost, the contango in the Brent market is reaching epic levels last seen in 2009. This means stocks all over the world are building at a very fast rate,” the bank said in a research note.

Contango is a market structure in which prompt prices are below longer-dated contracts.

In the short run WTI crude might trade above Brent to push barrels into Cushing, Oklahoma, the delivery point for the US futures contract, said the bank, which sees WTI at $32 per barrel at the end of the first quarter.

BofA lowered its average 2015 Brent price forecast to $52 per barrel from $77 and its WTI price outlook to $50 from $72. It sees 2016 average prices at $58 for Brent and WTI at $57 per barrel.