The U.S. investment bank Goldman Sachs cut its oil price forecasts on Monday. The bank expects Brent price of $50.40 a barrel in 2015, down from an earlier forecast of $83.75, and WTI price of $47.15 per barrel in 2015, down from an earlier forecast of $73.75.

Goldman Sachs lowered its 2016 Brent price forecast to $70, down from $90, and WTI price to $65, down from $80.

On a 3-, 6- and 12-month basis, the bank sees Brent to be at $42, $43 and $70 respectively, down from $80, $85 and $90.

The WTI price is expected to be at $41, $39 and $65 on a 3-, 6- and 12-month basis, down from $70, $75 and $80 a barrel.

Oil prices have dropped more than 50 percent since mid-2014, reaching their lowest levels since 2009.