Brent oil to end 2013 flat as Libya offsets weak demand

* Brent futures appear set to end year at around $111 * Traded between $96.75 and $119.17 in 2013 * U.S. crude traded between $85.61 and $112.24 * Libya's oil export ports still shut as deadlock drags on (Updates prices, paragraphs 5, 14 and 15) By Joshua Franklin LONDON, Dec 31 (Reuters) - Brent crude oil held above $111 per barrel on Tuesday supported by slashed Libyan output and violence in ...