Brent crude futures declined below $86 per barrel on 27 October, after Goldman Sachs cut its price projection for Brent and West Texas Intermediate by $15 a barrel for the first quarter of 2015.
Brent for delivery in December 2014 declined 0.29% to $85.88 (£53.37, €67.76) barrel as at 23:52 pm ET, while WTI was down 8 cents at $80.93.
London Brent crude for December delivery was trading 32 cents lower at $85.81 a barrel by 01:52 am GMT.
In a research note, Goldman said it currently expects prices of West Texas Intermediate (WTI) to decline to $75 a barrel from $90, and of Brent to $85 from $100.
The investment bank noted the price decline is due to rising production in non-OPEC countries outside North America, which is expected to outstrip demand.
In addition, the bank expects WTI to fall to as low as $70 a barrel and Brent to $80 a barrel during the second quarter of 2015 due to oversupply.
Prices would rise back to $75 for WTI and $85 for Brent in the second half of 2015, according to Goldman.
US crude futures edged up on Monday to hold above $81 a barrel, following a four-week slide that has pulled prices down by nearly 10% amid abundant supply and weak demand.
Crude oil prices have steadily been declining due to increased supply, despite political turmoil in producing nations such as Iraq and Libya.
Analysts have predicted that Saudi Arabia would call for an OPEC-wide production cut in the upcoming meeting of the Organization of Petroleum Exporting Countries (OPEC) scheduled for 27 November in Vienna, although officials from the Kingdom have not given any hint that Riyadh would seek to reduce output.
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The shale boom in the US has significantly boosted oil supply in the international oil market, and OPEC is likely to lose its influence. As a result, the biggest members in OPEC such as Saudi Arabia are cutting prices to stimulate demand and sustain market share.
"We believe that OPEC will no longer act as the first-mover swing producer and that US shale oil output will be called upon to fill this role," Goldman said in the report.
"Our forecast also reflects the realisation of a loss of pricing power by core-OPEC."
The bank added that global producers would have to cut output by almost 800,000 barrels a day next year to limit a build-up in inventories and ultimately balance the global oil market in 2016.