Oil prices rose above $83 a barrel Friday as the weak dollar drove investors to the market and concerns remained about a decline in crude inventories at a key Oklahoma terminal.

Light, sweet crude for November delivery on the New York Mercantile Exchange rose 36 cents to $83.24 a barrel in electronic trading by mid-afternoon in Europe. It rose as high as $83.38 during early trading in Asia.

On Thursday, the Nymex crude contract had jumped $2.58 to settle at $82.88 a barrel during the floor session.

Oil prices have risen to all-time highs in recent weeks, in part because the standoff between the West and Iran over its nuclear program has raised fears of a disruption in supplies from the Middle East.

The price gains have put the front-month contract back near the record levels hit late last week by the October contract on the day it expired. Last Friday, the October contract hit $83.90 a barrel before it settled at a record close of 83.32 a barrel.

The weak dollar — which fell to a new low against the euro Friday — makes oil seem inexpensive to people dealing in other currencies.

Also stoking concerns about crude supplies was a slight decline in oil inventories at the Nymex crude delivery point of Cushing, Okla., last week.

“This is fueling speculation that a supply shortage could be seen mid-continent” in the United States, said PVM Oil Associates in Vienna.

Analysts said a number of tropical weather systems were not affecting prices, as none are forecast to disrupt critical gas and oil infrastructure in the Gulf of Mexico.

Also supporting high oil prices is unrest in Nigeria, Africa’s biggest oil producer and one of the top suppliers to the United States, where a foreign oil worker was killed and another kidnapped on Thursday.

“Since 2006, almost one-fifth of Nigeria’s production has been off-line,” Austria’s PVM said. “The latest news could spark concerns regarding output in the coming months, when supply is already forecast to be tight.”

November Brent crude rose 53 cents to $80.56 a barrel on the ICE futures exchange in London.

Heating oil futures fell 0.76 cents to $2.2445 a gallon while gasoline prices fell 0.90 cents to $2.0849 a gallon. November natural gas futures were up 3.9 cents at $6.958 per 1,000 cubic feet.

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