Oil prices fell slightly on Friday as concerns about US-China trade talks and fresh data on surging US fuel stocks sent a chill through markets.

Brent crude oil futures were at 61.17 dollars a barrel at 0955 GMT, up 8 cents, or 0.13 per cent.

West Texas Intermediate crude for March delivery gained 51 cents, or 1 percent, to $53.64 a barrel on the New York Mercantile Exchange as of 12:25 p.m.

The International Energy Agency estimates Venezuelan reserves at 303.2 billion barrels, "but much of its oil is extra heavy, which is costly to extract", an IEA report said.

Meanwhile, markets digest the latest reports of potential USA sanctions on Venezuela's crude oil exports, which could make the oil markets tighter, with the OPEC output cuts already underway. USA crude inventories had posted declines in each of the previous two weeks.

Those differentials have narrowed since the government of Alberta announced last month it would impose crude oil production curtailments of 325,000 bpd starting January 1. OPEC member Venezuela is one of the world's largest oil producing countries, but its output has decreased from 2.4 million barrels per day in 2016 to a 70-year low of around 1.2 million bpd as the country has slipped into an economic crisis under Maduro's leadership. Sanctions would likely accelerate those trends.

"It will be costly for Venezuela but eventually they'll be able to sell that oil to Asia at a discount".

"Refiners would likely incur increased transportation costs to access alternatives" to Venezuelan oil, the Simmons analysts wrote.

Beyond oil supply, a key question for this year will be demand-growth.

Another consideration is whether Washington freezes the Venezuelan leadership's assets or alters the U.S. -Venezuela commercial relationship in other ways, Grais-Targow notes. "Over time, we can see oil production increasing".

The ongoing OPEC+ agreement to curb oil output remains the nearly exclusive source of support for prices.

Of apparent less concern to traders was news from Baker Hughes that US drillers added 10 oil rigs in the week to January 25, bringing the total count to 862 - the first increase in the number of operating rigs this year - however, like the Venezuela issue, this news may have a delayed reaction that could play out in coming days.

"It's certainly not a bad thing for Canadian heavy crude producers to have a competitor in a market like the U.S. Gulf Coast potentially go away", said John Auers, executive vice president at energy consultant Turner Mason & Co.in Dallas.

The No Oil Producing and Exporting Cartels Act, or NOPEC, is a congressional bill that seeks to apply USA antitrust laws to OPEC to prevent the group from coordinating production to influence oil prices.

Other industries that rely heavily on oil may feel impacts.