Brent crude for June delivery fell 19 cents to $40.14 a barrel. The May contract, which expired on Thursday, settled up 34 cents at $39.60 a barrel.

The dollar index rose in early trading in Friday, rebounding from a mid-October low hit in the previous session.

A stronger greenback makes dollar-denominated commodities including oil more expensive for holders of other currencies.

US crude production fell by 56,000 barrels per day to 9.179 million bpd in January, according to monthly data from the US Energy Information Administration released on Thursday.

That was the fourth straight month US domestic oil production had fallen and the lowest output level since October 2014, according to EIA data.

Economists and oil analysts polled by Reuters raised their average price forecasts for 2016 for the first time in 10 months, but cautioned that investor concerns over global oversupply, softening demand and weakening economic outlook could weigh on prices.

Analysts said US crude futures would average $39.70 a barrel in 2016, compared with an average of about $33.50 so far this year.

Brent futures would average $40.90 a barrel the survey of 31 pundits showed, against the current average of $35 for the year.

Imports of Iranian crude by Asia's four biggest buyers jumped by 24.6% to 1.27 million bpd from a year earlier to hit a two-year high in February, figures published on Thursday showed.

India showed the biggest increase in Iranian imports with a 111% rise to 215,800 bpd in February, from 102,000 bpd in the same month last year.

Investors are eyeing a slew of economic data including manufacturing PMI data from China and Europe and US nonfarm payroll figures later on Friday to give direction to oil prices.