Iraqi Kurdistan’s independence referendum Monday has returned its renegade oil industry to the spotlight, prompting Turkish President Recep Tayyip Erdoğan to threaten to cut off the region’s petroleum exports and Baghdad to call for a de facto boycott of Kurdish crude. Kurdistan has built up an independent oil sector against the odds, defying Iraq’s central government in Baghdad, which claims control over the country’s crude revenue. The result is an industry that accounts for 80% of the Kurdistan Regional Government’s revenue and that exports nearly 600,000 barrels of oil a day—about the same as petro-states like Qatar and Ecuador. More than half the region’s production is exported through a Turkish pipeline, the result of a controversial deal in 2013 with Ankara that allowed the Kurds to bypass Iraq’s state oil company […]