* Iran starts moving oil stored offshore to Asia
* Oil on track for third straight weekly decline (Updates throughout, changes dateline from SINGAPORE)
By Simon Falush
LONDON, July 17 (Reuters) - Brent crude oil rose slightly on Friday, underpinned by a weaker dollar and a power outage at Britain's largest oilfield, though a supply glut kept prices pinned near $57 per barrel.
Brent crude LCOc1 was up 15 cents at $57.07 by 0827 GMT. Front-month U.S. crude futures CLc1 were trading at $50.87 per barrel, down 4 cents from their last settlement.
"With the Iran deal people are aware there is more supply coming so all impetus for a price correction higher has gone," said Hans van Cleef, senior energy economist at ABN Amro in Amsterdam.
Iran has started to ship oil to Asia that it had been storing offshore for months after Tehran and six world powers reached a landmark nuclear deal on Tuesday, clearing the way for an easing of international sanctions on Iran. ID:nL5N0ZW4GC
Expectations of around 500,000 barrels per day more oil coming from Iran by the first half of next year, combined with rising U.S. shale production and high OPEC exports, have helped cut oil prices by nearly half from their year-ago level.
Britain's North Sea Buzzard oilfield shut on Thursday after experiencing problems on Wednesday night, several traders said. It was expected to come online by Friday. ID:nL5N0ZW1XZ
This supports Brent, as oil from the field contributes to the calculation of the benchmark's price.
The weaker dollar also helped support oil by making dollar-priced crude more affordable to holders of other currencies.
U.S. crude is heading for a third weekly decline and is down 3.5 percent this week, while Brent is more than 3 percent lower and also on track for a third week of declines. This would be the longest such losing streak since January.
In the United States, data from industry intelligence firm Genscape showed higher crude inventories at the Cushing, Oklahoma hub, the delivery point for the U.S. crude contract. ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
* GRAPHIC-World petroleum oversupply:
http://link.reuters.com/jaz84w
* FACTBOX-Oil price forecasts: ID:nL2N0ZV00W ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^>