Oil prices slipped on Friday as the forest fires menacing Canada's oil sands region were contained, but the market remained generally firm amid growing expectations of a demand pickup.

US benchmark West Texas Intermediate for delivery in June lost 41 cents to close at $47.75 a barrel.

In London trade, Brent North Sea crude for July lost nine cents to $48.72 a barrel.

Both contracts though were up from a week ago, when WTI closed at $46.24 and Brent at $47.78.

Traders showed rising confidence in a tightening of the supply-demand equation, with US output steadily falling, Nigeria and Canada suffering cutbacks, and some tentative signs of stronger growth in the global economy.

"There's still a lot of fundamental news that's pretty bullish: the wildfires in Canada, the chaos in Venezuela," said market analyst Carl Larry of Frost & Sullivan.

"Demand has started to outstrip supply. Sentiment is picking up quite a bit and perhaps prices may push above the $50 mark in the next couple of weeks, provided the dollar does not strengthen further," said IG analyst Bernard Aw.

In Fort McMurray, the center of Canada's oil sands production, officials said Friday that firefighters have contained the blaze that forced the shutdown of 1.2 million barrels a day of output.

But they said thick smoke in the area would continue to hamper the resumption of output.

The two largest oil sands facilities, operated by Suncor and Syncrude, remain shuttered.

"They remain under mandatory evacuation," said Shane Schreiber, head of the Alberta Emergency Management Agency.

"I can't see that being lifted until the air quality index becomes stable and until we get a couple more days of getting good firefighting done on that fire," he said.

Imperial Oil, meanwhile, said in a statement that it has resumed limited operations at its Kearl oil sands site, 70 kilometers (44 miles) north of Fort McMurray.

Production pressures may push oil prices lower to start Friday
New York (UPI) May 20, 2016 - Crude oil prices opened relatively flat on Friday on reports of oil-related developments in Libya and higher-than-expected production from offshore Norway.

Crude oil prices have recovered more than 80 percent since dipping below the $30 mark in January. Prices in early 2016 were influenced by talks of a production freeze for Russia and some members of the Organization of Petroleum Countries, though that deal collapsed after Iran said it was determined to regain a market position lost to sanctions. Recent rallies were triggered by production concerns in Canada and Nigeria, as well as sentiment that balance between supply and demand had returned to the market.

Libya, an OPEC member whose production is far below levels from before civil war, said national forces this week were able to seize control of more than a dozen fields controlled by the Islamic State terrorist group. While Libyan output is low, the move could signal a shift in a campaign targeting terrorist financing.

In Norway, the government said oil production of an average 1.63 million barrels per day in April was 3 percent higher than it expected and 4 percent higher year-on-year.

Crude oil prices were relatively flat at the open. The price for Brent crude oil was only a fraction of a percent lower to start the day at $48.79 per barrel. West Texas Intermediate, the U.S. benchmark price, moved marginally higher to open at $48.21 per barrel.

Prices could be influenced later in the day Friday after oil services company Baker Hughes releases its weekly data on rig counts. An increase in the number of rigs would suggest the market rebound is supportive of a return to services sidelined by the decline that started 2016.

For April in the United States, industry data from the American Petroleum Institute show crude oil production averaged 8.9 million bpd, a 7.8 percent decline from last year and the lowest level in nearly two years. Consumer demand, meanwhile, rose to its highest level for April on record as lower crude oil prices meant lower retail prices for petroleum products.

The average retail price for a gallon of regular unleaded gasoline in the United State has increased 9 percent since the start of April.