By Sabina Zawadzki
LONDON (Reuters) - Oil futures were little changed on Friday, capping a week of price growth supported by the prospect of a crude production cut by OPEC countries even though doubts lingered over the cartel's ability to wipe out a persistent excess of oil.
Brent (LCOc1) traded at $52.50 at 1410 BST, a cent lower, while U.S. crude oil futures were a cent up at $50.45. Both futures contracts see-sawed during the European trading day with Brent touching $52.84 earlier, two cents below the 2016 high.
The front-month contracts have now risen more than 10 percent since OPEC countries, including Middle Eastern foes Saudi Arabia and Iran, announced a tentative deal to moderately cut their output on Sept. 28.
Details of the cuts are expected to be hammered out at a meeting on Nov. 30, leading market participants to believe prices would be supported above the $50 a barrel mark until then.
But most agree a formal agreement will be hard work as macroeconomic considerations such as falling state revenues and the competing political aims in a regional power struggle between Gulf states and Iran will play out in discussions.
OPEC leaders were expected to meet with officials from oil producing behemoth Russia next week.
Shorter-term, support also came from Hurricane Matthew in the U.S. Gulf, which could disrupt U.S. oil imports and lead to fuel shortages.
But analysts said the agreement's support was fragile, given the overhang of physical crude oil.
"This isn't really sustainable," Hamza Khan, head of commodities strategy with ING, said of this week's rally, adding that fears the hurricane could impact U.S. oil stocks were one of the only fundamental factors supporting the market. "It all could be over by next week."
With both front-month contracts above $50 per barrel and each forward curve in contango, in which contracts for future delivery are more expensive than those for immediate sale, the entire crude futures complex has moved back over $50 per barrel. (Chart: http://tmsnrt.rs/2dz0bQH)
But as a sign of persistent oversupply, in part due to high refinery maintenance, the Brent crude oil forward curve has steepened into its biggest contango since July.
Some warned this could ultimately hurt OPEC member nations by giving a boost to other producers.
"Many U.S. shale oil producers have now hedged their production, which is likely to put the brakes on the price rise," analysts at Commerzbank (DE:CBKG) said in a note. "In other words, OPEC is shooting itself in the foot in the medium to long term."
Top exporter Saudi Arabia cut its benchmark crude prices to Asia this week, while Libya exported the first oil tanker from the port of Zuetina since 2015, adding to global supplies.