Oil prices hovered near $109 a barrel on Wednesday as supply disruptions balanced against demand worries, and caution stalled investors ahead of US Federal Reserve chairman Ben Bernanke\'s speech at the end of the week. Bernanke is expected to express his disappointment over US growth and offer remedial action to kick-start the world\'s largest economy and key oil consumer when he speaks to a central bank conference tomorrow in Jackson Hole, Wyoming. \"There is not a lot of impetus in either direction, with the market caught between problems with supply on one side — with Libyan exports offline and probably offline for some time — and weak economic growth and slowing demand,\" said Tobias Merath, head of Private Banking Commodity Research at Credit Suisse. Oil trading was likely to remain cautious at least until Bernanke\'s speech tomorrow, which could help clarify the outlook for US economy and provide momentum, Merath added.