The global benchmark is on course for a weekly loss of over 4 per cent.
Front-month Brent crude oil futures were at $75.82 a barrel at 0656 GMT, down 35 cents, or 0.5 percent, from their last close.
Financial markets have been hit hard by a range of worries, including the U.S. Faltering confidence in the strength of the global economy comes as swelling American oil stockpiles spark fears about a re-emergence of a price-killing glut.
Over 100 trade codes have been offered to foreign buyers to allow them to get engaged in trading Iranian crude and oil products in the Energy Bourse, Kardor told the IRNA on Friday.
West Texas Intermediate for December delivery fell as much as 88 cents to $66.45 a barrel on the New York Mercantile Exchange, and was at $66.68 at 11:18. As it was, the prices of Brent crude had gone down by nearly 5% across the week. I think US and Saudi due to mutual interest are interested to manage any tension with aimed of decreasing Iran's role in world oil market. The shift by Beijing, Iran's top customer, gives the USA a building block in an economic barrier around Iran as it prepares to renew sanctions on the country's energy sector in early November.
Only recently, Saudi Arabia's Oil Minister Khalid al-Falih had said that the kingdom has no intention of an oil embargo on Western consumers, despite the current crisis following allegations that it murdered journalist Jamal Khashoggi.
Saudi Arabia's OPEC governor said on Thursday the oil market could face oversupply in the fourth quarter.
U.S. crude CLc1 was down 60 cents, or 0.9 per cent, at $66.73. Washington is still insisting on full compliance to ensure no Iranian oil exports find a market.
Meanwhile, U.S. production is soaring, boosted by technological advances that have enabled drillers to tap shale formations, with output this year forecast to overtake the previous annual record in 1970.
US energy firms added oil rigs for a third straight week, keeping the rig count at its highest in over three years, General Electric Co's Baker Hughes energy services firm said.
In the months following the full implementation of sanctions in November, the total volumes of crude oil and condensate coming off the market will become more apparent.
Economic uncertainty and the woes of the Asian stock market unsettled the oil price this week to the downside.