Updated from 1:36 p.m. ESTOil prices perked up Tuesday as a futures expiration sowed volatility. Crude for April delivery added 15 cents to finish trading at $60.57 a barrel on Nymex. The April contract for crude expires Tuesday, and prices were choppy as traders exited the position and bought May's. Light volume also magnified the price swings. "People are rolling over contracts," said Larry Young, senior trader at Infinity Brokerage Services in Chicago. "Traders in this market need to be fully in." U.S. crude inventories currently stand at seven-year highs thanks to ongoing refinery maintenance and relatively low spot prices. Since the start of the year, crude stockpiles have climbed 7%. They now stand at 339.9 million barrels. Many refineries are closed for seasonal maintenance to switch over to summer-blended gasoline. Crude, which is processed into heating oil and gasoline, among other petroleum products, builds up at refiners and boosts supply levels. Refiners are also opting to buy crude on the spot market, rather than draw on their supplies, because spot oil is cheaper. On Monday, oil for delivery in April closed at $60.42, compared to $61.96 for May crude. On Wednesday, the U.S. Energy Department releases its weekly update on domestic fuel inventories, and traders are expecting another larger jump in inventories for the week ended March 17. Analysts polled by Bloomberg were calling for a 2.4 million-barrel increase in crude to a total of 342.3 million barrels. Unleaded gasoline picked up 1 cent to close at $1.83 a gallon, while heating oil added 3 cents to $1.77 a gallon. Gasoline inventories, which are slightly above last year, likely fell 0.4% or 1 million barrels as demand rose and refineries operated at lower capacity. Distillates, which include heating oil and jet fuel, probably declined 2.1 million barrels. Both estimates are from Bloomberg's survey of energy analysts. There is 13% more distillate fuel in storage now than last year. High inventories come at a good time. Millions of Americans will be taking to the roads for vacations and weekend trips starting in the spring, increasing demand for gasoline. Already the appetite for gasoline has risen 2% over last year. "A supply glut is a possibility, but peak demand will be starting soon and drawing them down," said Chris Ovrebo, a broker with FCStone in Minneapolis, Minn. Plentiful supplies were overshadowing the standoff with Iran over its nuclear ambitions. The five permanent members of the U.N. Security Council, plus Germany, met on Monday but failed to agree on a course of action. Russia and China blocked a statement that would have asked Iran to end its small-scale uranium enrichment. The Security Council meets in a formal meeting later Tuesday. The U.S. has threatened economic sanctions against Iran, OPEC's second-largest producer, if it continues nuclear development activities. Tehran declares that it needs nuclear power to generate more electricity for its population. The West suspects Iran's real goal is nuclear weapons. A trade embargo against the country would inevitably drive up oil prices and trim supplies because there are not enough inventories worldwide to make up for Iran's production. Nigeria has lost around $1 billion in revenues from rebel attacks on its petroleum industry, the country's oil minister, Edmund Daukoro, said on Tuesday. Militants, who want to destabilize the central government and gain a share of the country's oil wealth, have blown up pipelines, attacked platforms and kidnapped foreign oil workers. Daily output has dropped 25% to 1.6 million barrels this year. Nigeria is the largest crude producer in Africa and has become increasingly important to the U.S. as it reduces its dependence on Middle Eastern oil. Nigeria supplies about 15% of oil in the U.S., a figure that is expected to climb to 25% in the next decade. Natural gas rose 3 cents to a close of $6.87 per million British thermal units as the winter heating season ended amid plentiful supplies. There is 31% more natural gas in storage now than at the same time last year. In trading Tuesday, shares of the supermajors were gaining ground despite lower oil prices, which often push down energy-related stocks. ExxonMobil ( XOM) fell 15 cents to $60.51, Chevron ( CVX)dropped 21 cents to $56.54, and BP ( BP) inched down 45 cents to $68.30. Total ( TOT)was declined $1.36 to $127.11, and Shell ( RDS-A) dipped 59 cents to $60.69.