US production jumped in recent years because of techniques including hydraulic fracturing, or "fracking", which is the use of chemicals, sand, water and high pressure to crack rock formations deep below ground, releasing more oil and natural gas.
Washington will consider waivers for Iranian oil buyers such as India but they must eventually halt crude imports from Tehran, US Secretary of State Mike Pompeo said last week in New Delhi after a meeting of high level officials.
In a move heavily opposed by Iran, OPEC and other oil producers including Russian Federation agreed in June to boost crude output by around a million barrels a day, reversing course after supply cuts that had cleared a global glut and boosted prices.
Leave aside concerns about prospects for developing economies and the impact of Trump's trade wars that are darkening the outlook for oil demand.
Brent was set for a 2 percent weekly rise and WTI 1.7 percent.
USA light crude futures were up 27 cents or 0.39 percent at 68.86 after tumbling 2.5 percent in the previous session.
Florence pours rain on the Carolinas; death toll at 5
The hurricane is expected to make landfall on Friday, with heavy rain and hurricane-force winds potentially lasting for days. That's enough to fill the Chesapeake Bay, or cover the entire state of Texas with almost 4 inches (10 centimeters) of water.
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I have seen a lot of matches, of Cardiff and PAOK, West Ham and Liverpool , so I had to work. "For me, my life is on the pitch with the players".
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Oil ETFs should not count on a bump from the drop off in oil supply out of Iran due to USA economic sanctions as the Organization of Petroleum Exporting Countries quickly stepped in to fill in the gap, raising global supply to a record high.
"The price action of yesterday confirms $80.00 a barrel as a strong resistance line in Brent", consultancy Petromatrix said in a research note.
Traders also continued to watch for any impact on the energy market from Hurricane Florence.
Washington reimposed some of the financial sanctions from August 6, while those affecting Iran's petroleum sector will come into force from November 4.
India lifted about 658,000 barrel of oil per day (bpd) from Iran in April-August, according to data obtained from trade sources by Reuters, and the cuts projected for September and October would drop the daily average over those two months by about 45 percent to 360,000-370,000 bpd.
China will not buckle to US demands in any trade negotiations, the major state-run China Daily newspaper said in an editorial on Friday, after Chinese officials welcomed an invitation from Washington for a new round of talks.