OPEC’s crude production fell by 310,000 barrels a day in December, as unplanned disruptions in Nigeria reduced the group’s supply before deliberate cuts take effect this month. Nigeria’s daily output dropped by 200,000 barrels to 1.45 million in December, ending three months of gains as the African nation struggled to restore capacity after a year of militant attacks on oil infrastructure. Saudi Arabia’s production fell by 50,000 barrels a day while Venezuela declined by 40,000. “Crude production in Nigeria in December was once again severely impacted, mostly due to a field maintenance as well as a strike of port workers,” Amrita Sen, chief oil analyst at London-based consultant Energy Aspects Ltd., said by e-mail. The decline in December comes as OPEC, which controls around 40 percent of global supply, is planning to curb output in a bid to boost oil prices. The organization reached a historic deal last month […]