Libya’s crude output dropped 11 percent as clashes among rival armed groups over the last 10 days led to the closing of some of the OPEC nation’s biggest oil export terminals, forcing a number of fields to halt production. Output fell by about 80,000 barrels a day to 620, 000 barrels since fighting among armed groups broke out on March 3, according to a person familiar with the matter, who asked not to be identified because of a lack of permission to speak to media. Es Sider, the country’s biggest oil port, and Ras Lanuf, its third-largest, remain closed, according to the person. Crude production halted at Waha Oil. Co., which pumps crude to Es Sider. Waha is a joint venture between the state oil company National Oil Corp., Hess Corp., Marathon Oil Corp. and ConocoPhillips. The clashes dealt a blow to recent gains in the North African nation’s […]