Oil hovered around its one-month high as new forecasts predicted more cold weather in the US Northeast, the world's largest consumer of heating oil.
At 9.58am, front-month Brent North Sea crude contracts for March delivery were down 6 cents at $58.35 a barrel, after gaining $1.69 to settle at $58.41 on Friday.
Meanwhile, front-month New York light sweet crude contracts for March delivery fell 2 cents to $59.02 a barrel, after rising $1.72 to close at $59.02 Friday.
Demand for heating fuels is expected to remain strong this week as cold weather in the US Northeast looks set to continue.
Private forecaster Accuweather said strong winds 'will make the already frigid temperatures feel even colder'.
However, oil prices were under slight pressure from news oil workers unions in Nigeria suspended plans to strike yesterday - easing market fears of a supply glitch from the world's eighth largest exporter.