Oil prices rallied above $31 a barrel on Friday as investors hunted for bargains after a volatile week and bet that fresh stimulus measures by major central banks would improve demand for the beleaguered commodity, the Wall Street Journal reported.

Oil was also boosted by cold weather on both sides of the Atlantic, which is fueling hopes of improving demand for heating oil.

Sweet crude for February delivery recently rose $1.82, or 6.20% to $31.38 a barrel on the New York Mercantile Exchange.