Oil companies that piled into Iraqi Kurdistan after Saddam Hussein’s ouster are running into trouble, unraveling the region’s promise as source of easy-to-drill oil and threatening Iraq’s production surge. The regional government’s Ministry of Natural Resources declined to comment. Any slowdown in Kurdistan’s oil production could affect energy markets because previous drilling success there helped Iraqi output climb by almost 20% in 2015 to 3.99 million barrels a day—about 4% of global output. This mounting production contributed to a global glut and helped sink prices to $27 a barrel in January, the lowest level in 12 years. Kurdistan, a region about the size of Switzerland, was once believed to hold as much petroleum as the North Sea. It has been a magnet for Western investment in the past decade—a rarity in the Middle East, […]