Oil prices up in world markets 

Oil prices surged after a pipeline that delivered oil to Midwest refineries was shut down, raising questions about how long the supply may be disrupted. Benchmark oil for October delivery rose $2.20 to settle at $76.45 a barrel on the New York Mercantile Exchange.
<p>Enbridge Energy Partners LP closed the pipeline Thursday afternoon after it began leaking in suburban Chicago. Spokeswoman Terri Larson said there is no time frame yet on when it will reopen. She said the site is contained and crews hope to begin excavation around the pipe later Friday. The pipe carried about 670,000 barrels per day from Superior, Wis., to Griffith, Ind.
<p>Although oil and gasoline inventories are plentiful, traders are concerned that Midwest supplies could tighten if the pipeline stays closed for some time, analysts said. In turn, that could send retail gasoline prices up in the Midwest.