Global oil markets will swing from surplus to deficit in the first half of 2017 as OPEC and other producers follow through on an agreement to cut supply, according to the International Energy Agency. Oil stockpiles will decline by about 600,000 barrels a day in the next six months as curbs by OPEC and its partners take effect, said the agency, which had previously assumed inventories wouldn’t drop until the end of 2017. Russia, the biggest producer outside OPEC to join the deal, will gradually implement the full reduction it promised, according to the IEA. Oil has gained more than 16 percent since the Organization of Petroleum Exporting Countries agreed on Nov. 30 to trim output for the first time in eight years, an accord expanded on Dec. 10 with the participation of 11 non-members including Russia and Kazakhstan. “Before the agreement among producers, our demand and supply numbers […]