Brazilian oil workers on more than 40 offshore platforms are threatening to go on strike next week unless Petrobras, a state-run oil firm, gives them an extra day off at the end of each 14-day stint.
Marcos Breda, a union spokesman, said that workers wanted the time needed to get off platforms after the two-week shift to be considered as a working day, for which they should be compensated with a day off.
Crude had fallen by nearly $10 a barrel over two days at the beginning of the week, but rebounded by more than $5 a barrel on Thursday as anxiety heightened about supplies being disrupted in key producers.
Oil prices have risen seven-fold since 2002 amid surging demand from China and other emerging markets, and jumped 50 per cent this year alone, damaging the economies of consumer nation's already hit hard by the global credit crisis.
The resurgence in crude prices at the end of the week increased concerns that US drivers could see $1.05 a litre petrol prices become permanent and home heating could bemuch more expensive this winter.
Heating oil futures rose to a trading record of $4.1586 before settling at $4.0766 a gallon, up 3.92 cents.
Petrol futures also rose to a new trading record of $3.631 a gallon before finishing at $3.5632, up 5.23 cents.
"If you think your gasoline bills are expensive now, wait till you get your home heating bill this winter,"Stephen Schork, an analyst and trader in Villanova, Pennsylvania, said.