Organisation of Petroleum Exporting Countries (OPEC) 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 in January. 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 terror 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 per cent of global supply, is planning to curb output in a bid to boost oil prices. The organisation reached a historic deal last month with Russia and other non-members to cut global production by almost 1.8 million barrels a day starting this month. Under the terms of December's agreement, OPEC’s total output including Indonesia would fall to 32.5 million barrels a day. Compliance with that target will be judged against on independent estimates compiled by OPEC, which can vary from the Bloomberg News survey. (Angelina Rascouet and Julian Lee/Bloomberg)