Brent crude oil prices increased on Friday, supported by a weaker dollar and a power failure at and a UK oilfield.

Brent crude rose 15 cents at $57.07, while front-month US crude futures were trading at $50.87 per barrel, a drop of 4 cents compared with their last settlement, Reuters reported.

The North Sea Buzzard oilfield in the UK experienced problems on Wednesday night and was closed on Thursday.

"With the Iran deal, people are aware there is more supply coming so all impetus for a price correction higher has gone."

Located about 60 miles north-east of Aberdeen, the North Sea Buzzard oilfield supplies about 70,000-180,000 barrels of crude per day, according to BBC.

Oil prices gained as oil from the field, one of the biggest contributor to Forties crude stream, influences the calculation of the benchmark’s price.

Due to a weaker dollar value, oil prices witnessed a rise by making dollar-priced crude affordable to other currency holders.

ABN AMRO Amsterdam senior energy economist Hans van Cleef told the news agency: "With the Iran deal, people are aware there is more supply coming so all impetus for a price correction higher has gone."

On Tuesday, Tehran and six world powers reached a landmark nuclear agreement.

The deal cleared the way for an easing of international sanctions on Iran which started shipping stored oil to Asia.

Data from industry intelligence firm Genscape in the US highlighted higher crude inventories at the Cushing hub, Oklahoma.