Brent drops below $109 on hopes diplomacy will ease Ukraine crisis

* U.S. crude stocks seen up by 1.8 mln barrels -poll * Iran says exporting just 1 mln b/d, much less than IEA estimates By Keith Wallis SINGAPORE, April 15 (Reuters) - Brent crude futures dropped below $109 a barrel following a surge to a six-week high in the previous session, as investors looked ahead to a meeting in Geneva that they hoped would bring a political resolution to the escalating