Libya’s crude-oil production has more than tripled in the past six months, imposing an obstacle to the Organization of the Petroleum Exporting Countries’ plans to raise petroleum prices by collectively lowering output. Oil prices have surged 19% to more than $55 a barrel since OPEC’s Nov. 30 deal to throttle down its output by about 4%, but the surge in Libyan production challenges a bet the cartel made against the North African country. OPEC exempted Libya from any requirement to cut because the country has been riven by…