Crude oil prices fell Tuesday, but refined products like gasoline and heating oil rose because of possible refinery problems in the United States, reported AP. Light, sweet crude for April delivery fell 17 cents to US$61.60 a barrel in electronic trading on the New York Mercantile Exchange. Gasoline futures rose 1.92 cents to US$1.7625 a gallon (3.8 liters) while heating oil gained half a cent to US$1.7425 a gallon. April Brent crude futures on the ICE Futures exchange in London fell 13 cents to US$62.07 a barrel. Oil prices fell after surging US$1.81 to settle at US$61.77 the previous day on nagging concerns about unrest in Nigeria and the possibility of U.N. sanctions against Iran, the No. 2 producer within OPEC, for its nuclear ambitions. In Nigeria, recent attacks by militants on pipelines and oil facilities have left the country's production down by about 400,000 barrels a day. "We would expect the potential for further chaos in Nigeria to provide a floor for prices around US$60 a barrel, and we expect Nigeria will continue to be a major issue in terms of supply security up to, and probably beyond, next year's elections," wrote Barclays Capital's analysts, led by Kevin Norrish, in a research note. U.S. oil products prices rose on talk of continuing restart problems at BP PLC's Carson, California, refinery and ongoing problems at Valero Energy Corp.'s Benicia refinery. This could prompt U.S.-based refiners to seek more gasoline from fellow refiners and probably increase purchasing from Northwest Europe. Gasoline and distillates stocks are forecast to decline in weekly data to be released Wednesday by the U.S. Department of Energy's statistical arm, the Energy Information Agency, according to a Dow Jones Newswires survey. Commercial gasoline stocks are likely to have fallen 800,000 barrels, while distillates stocks are projected to fall for a fourth straight week, by 1.5 million barrels for the week ended March 10. But crude oil inventories are likely to have continued building for a fourth consecutive week, rising by 2.3 million barrels over the week.