LONDON (Reuters) - Brent crude futures rose close to $112 a barrel on Friday, adding to the previous day's rally on the prospect of Nigeria's oil unions halting the sector from Sunday, part of a national strike against the end of fuel subsidies.
Brent crude futures rose 64 cents to $111.90 a barrel by 0931 GMT after rising more than a $1 to hit an intraday high of $112.50.
U.S. light crude futures were up 51 cents at $99.61 per barrel, after touching a high of $100.19 earlier in the session.
"The main risk heading into the weekend is Nigeria, where discussions are ongoing between the government and the unions on the fuel subsidies," Olivier Jakob from Petromatrix said.
One of Nigeria's main trade unions said talks with President Goodluck Jonathan over the government's removal of publicly popular fuel subsidies were 'fruitful' and ongoing, but strikes would continue until an agreement was reached.
Nigeria produces more than 2 million barrels of crude oil per day and is a key supplier to the United States, Europe and Asia.
Goldman Sachs oil analysts said in a note on the commodities sector outlook that they view "substantially greater" upside risks to oil "given the stronger fundamentals and recent events surrounding Iran and Nigeria".
Victor Shum, of energy consulting firm Purvin & Gertz, sees more upside risks due to political tensions, and expects Iran will be 'a longer-term issue' with no immediate supply disruption. Shum sees U.S. oil prices hovering around $100-$105 a barrel range for most of the month, with Brent having a $10 premium over U.S. oil.
Tension over Iran also supported prices as efforts to tighten the diplomatic net around Tehran continued.
U.S. allies in Asia and Europe said they would support Washington's campaign to cut Iran's oil exports, but fear of self-inflicted economic pain is tempering enthusiasm for such an embargo.
The United States placed sanctions on China's state-run Zhuhai Zhenrong Corp - which it said was Iran's top supplier of refined petroleum products - as it sought to impress on Beijing and Tehran its resolve to increase economic pressure over Iran's nuclear program.
But India will keep doing business with Tehran, a senior Indian cabinet minister said on Thursday.
