Crude oil futures logged marginal gains on 17 October, but finished lower for the week, with key exporting nations refusing to cut output amid a supply glut and forecasts for weak crude demand the world over.
Brent December contract finished 57 cents, or 0.7%, higher at $86.16 a barrel on Friday.
The global benchmark lost 4.9% for the week as a whole.
US November contract finished five cents, or 0.1%, higher at $82.75 a barrel on Friday.
Light, sweet crude lost 3.6% for the week.
Opec member countries -- the group of 12 mostly Middle Eastern producers who pump a third of the world's oil – are scheduled to meet in November in Vienna, and traders will track their decisions on production targets.
According to reports, producers including Saudi Arabia, Kuwait and the United Arab Emirates propose to oppose any reduction in Opec oil-production ceiling at the meeting.
Goldman Sachs said in a note to clients that crude oil's selloff has been fuelled by investor positioning based on expectations rather than a real-world disparity between supply and demand, and that if prices got low enough they could trigger renewed demand and consumption.
The bank said that "prices have likely overshot to the downside".
Oil prices dropped by more than $1 per barrel on 16 October and Brent crude hit a fresh four-year low at below $83, amid growing concerns over the health of the global economy.
The International Energy Agency (IEA) this week cut its oil demand growth forecast for 2015 as global economies remain weak, prompting predictions that Opec members might prefer to keep selling at lower prices than lose their market.