Lead U.S. oil company negotiator Shell Oil Co said face-to-face negotiations on Friday with the United Steelworkers union (USW) failed to yield an agreement to end the 20-day-old U.S. refinery strike.

Crude prices ended mixed on Friday as the number of U.S. rigs drilling for oil fell far less than expected this week, while heating oil jumped 6 percent after severe winter cold crimped output at three refineries.

Brent crude oil fell below $60 a barrel on Friday as oversupply, supported by record-high U.S. crude stocks, weighed on the market.

Oil markets edged up on Friday to halt a two-day drop, helped by expectations that data later in the day would show a continuing decline in the U.S. oil rig count, a clear sign of the pressure the tumble in crude has put on oil producers.

Oil prices tumbled on Thursday as U.S. inventories were expected to hit record highs, while a possible rise in Saudi output could stoke oversupply built up in the past few months.

An explosion and fire ripped through a gasoline processing unit at an Exxon Mobil Corp refinery near Los Angeles on Wednesday, leaving California with the threat of higher gasoline prices.

Oil dropped below $62 a barrel on Wednesday, failing to build on gains of more than 1 percent in the previous session as analysts said a recent rally in prices was overblown.

Oil rose to $62 a barrel on Tuesday, close to its 2015 high, supported by threats to Middle East supplies and expectations lower prices may prompt a slowdown in U.S. output.

Brent crude extended its rally on Tuesday, moving further away from six-year lows hit in January, but some analysts warned that prices had risen too far and could face a downward correction.

Craig Uden, who fattens cattle for beef on his Nebraska feedlot, expects to cut his energy costs by as much as a quarter this year because of falling oil prices - a silver lining in an otherwise tough rural economy.