Oil futures rise on supply concerns

NEW YORK -- Oil futures jumped back above $91 Friday, building on the previous session's gains on renewed concerns about supply disruptions and also advancing on waning fears of a recession that would curb demand. Crude gained on word that oil exports from Nigeria, Africa's biggest oil producer and a major U.S. supplier, could fall by as much as 1 million barrels a day due to the nation's deteriorating security situation and planned maintenance. Nigeria is locked in a long-running battle with rebels intent on hurting the nation's oil industry infrastructure.