** Oil producers' U.S.-listed shares down premarket as oilprices drop below $49 per barrel
** Brent prices at $48.78 per barrel and U.S. crude at $47.16 per barrel after Goldman Sachs slashedshort-term price forecasts, Gulf producers showed no signs ofcurbing output
** Exxon Mobil Corp shares down 0.6 pct at $91.55,Chevron Corp down 0.94 pct at $107.19, Royal Dutch ShellPlc down 1.5 pct at $63.28
** BP Plc down 1 pct at $36.19, Petroleo BrasileiroPetrobras SA down 2.7 pct at $6.87, ConocoPhillips down 0.96 pct at $64.30
** Oilfield services companies also hit: Schlumberger Ltd down 2.5 pct at $79.17, Halliburton Co down 1.8pct at $39.10, Baker Hughes Inc down 2 pct at $55.40,National-Oilwell Varco Inc down 1.4 pct at $61.04
** Contract drillers fall: Seadrill Ltd down 3.1pct at $9.64, Transocean Ltd down 2.2 pct at $15.75