** U.S.-listed stocks of the world's biggest oil and gasproducers down premarket after oil prices drop to fresh5-1/2-year lows
** Royal Dutch Shell Plc shares down 3.4 pct at$64.72, Total SA down 3.5 pct at $49.39, BP Plc down 4.2 pct at $36.50, Statoil ASA down 4.8 pct at$16.59, Vale SA down 3 pct at $7.69
** BHP Billiton Ltd down 2.7 pct at $46.26, ExxonMobil Corp down 1.2 pct at $91.70, Chevron Corp down 1.8 pct at $110.51, Petroleo Brasileiro Petrobras SA down 6.2 pct at $6.34
** Oil prices have been dipping on concerns over a surplusof global supplies and lackluster demand, losing more than halftheir value since a peak in June last year
** Brent crude for February dropped as low as $54.85a barrel while U.S. crude slid to $51.36 a barrel onMonday - the lowest since May 2009