Benchmark Brent crude was at $65.83 per barrel at 1145 GMT (7.45 a.m. EDT), up 29 cents after hitting a session high of $66.01, on track for a 1 percent weekly decline. U.S. crude was 48 cents higher at $59.42 a barrel, little changed on the week.
Brent was still around $4 below the 2015 peak reached earlier in the week, hit by a resurgent dollar and signals that some U.S. producers would ramp up drilling if prices continued to rise.
Analysts said Brent seemed capped around $70, and may already be overvalued as oversupply continued and U.S. producers, which have sharply reduced drilling in recent months of low prices, could increase production.
"The small drop in U.S. production in recent weeks certainly does not justify the 30-40 percent price increase" since January, said Hans van Cleef, senior energy economist with ABN AMRO.
"The oil market is still very much supply-driven, and in the end, we face a huge oversupply."
But U.S. shale producers indicated that the recent gains in oil prices could lead to new drilling. Harrold Hamm, chief executive officer of Continental Resources, said on Thursday that $70 a barrel is a price "that turns it on for us".