Oil market set for more volatility after turbulent week

World oil prices swung between sharp gains and losses this week as possible efforts to finally tackle a supply glut were offset by lingering concerns over weak global economic growth. "This week's big story (for commodities) has, of course, been the rebound in oil prices on unconfirmed reports that Russia and OPEC may finally be willing to agree coordinated cuts in output," Capital Economics analyst Caroline Bain said on Friday.