** Short-covering squeezing oil stocks higher despite moresharp falls for crude, according to two London-based traders
** Shell most-traded on FTSE 100 by averagevolume, rising 2.2 pct as Brent crude falls 2.8 pct
** BG Group, Tullow, Ophir, TGS and Petrofac all up between 1.3 to 2 pct
** Signs of covering in other oil-related names as positionsunwind into year-end, traders say (RM: alasdair.pal.thomsonreuters.com@reuters.net)