Along a bumpy dirt track to the west of Erbil, near the town of Gwer, tanker trucks trundle to a tiny, makeshift oil refinery – one of the roughly 150 “topping plants” that now underpin the hopes of foreign oil companies looking to monetize their investments in Kurdistan.The centerpiece is a steel boiler corroded with rust along its welding seams. From one side, a maze of cooling pipes zigzags through a pit of dirty water. A rudimentary distiller separates fuels into six, three-meter-high …