Oil prices rose on Wednesday, buoyed by an official forecast showing slower-than-expected US production, and as US sanctions stall exports from Venezuela, reports Reuters.
International Brent crude oil futures were at $66.89 a barrel at 0955 GMT, up 22 cents, or 0.33 per cent, from their last close.
US West Texas Intermediate crude futures were at $57.31 per barrel, up 44 cents, or 0.77 per cent.
The US Energy Information Administration (EIA) said on Tuesday that US crude production was expected to grow more slowly in 2019 than it had previously expected, averaging about 12.30 million barrels per day (bpd).
The EIA revised down its projected 2020 production figure from 13.20 million bpd to 13.03 million bpd.
"While the revision is small, the comforting part for bulls was that the direction of the revision was down rather than up," Harry Tchilinguirian, global oil strategist at BNP Paribas in London, told the Reuters Global Oil Forum.
US crude stocks also fell unexpectedly last week, data from the American Petroleum Institute showed on Tuesday, in a good sign for oil demand as supply from various producers was being curbed.
"The oil market maintained its buoyancy, thanks to Monday's Saudi commitment to deep supply cuts and power outages in Venezuela crippling the loading of oil at key terminals," Tchilinguirian added.
Oil prices have been pushed up this year by supply cuts led by the Middle East-dominated Organisation of the Petroleum Exporting Countries.
Saudi Energy Minister Khalid al-Falih said on Sunday that the production-curbing agreement would likely last until at least June. Saudi Arabia, the world's top oil exporter, indicated on Monday that it would cut April exports.
Markets have been further tightened by US sanctions against oil exports from OPEC members Iran and Venezuela.
Venezuela's worst blackout on record has left most of the country without power for six days, with hospitals struggling to keep equipment running, food rotting in the tropical heat and exports from the country's main oil terminal stranded.
"Failures in the electrical system ... (are) likely to accelerate the loss of 700,000 barrels per day" in oil supply, Barclays bank said.
National Australia Bank reported a mixed outlook for oil, with global economic concerns and strong oil supply growth from the United States keeping prices in check but OPEC supply cuts and US sanctions on Iran and Venezuela driving them up.
Another report from Dubai adds: Iran is discreetly scouring the globe for second-hand oil tankers to replace its ageing fleet and keep crucial crude exports flowing as US sanctions start to bite, Iranian and Western sources said.
Since US President Donald Trump reimposed sanctions in November, exploratory talks with South Korea for up to 10 new supertankers have stalled, Panama has removed at least 21 Iranian tankers from its registry and Tehran is now looking for extra vessels in places such as Vietnam, the sources said.
Washington has put restrictions on Iran's port, energy and shipping sectors but it has given waivers to the country's eight biggest oil customers, which include China, India and Japan, so they can keep buying Iranian crude.
With oil exports accounting for an estimated 70 per cent of Iran's revenues, maintaining an effective fleet of tankers to store and move that oil is crucial for Tehran.
But potential sellers of used vessels are more wary this time round after a Greek network that helped Iran buy tankers under previous sanctions was blacklisted. Western insurers are also steering clear, complicating Iran's attempts to export crude to US-approved buyers.
If Iran runs into difficulties exporting its oil it could have a significant impact. Besides the importance of oil for its budget, Iran is estimated to produce about 2.8 million barrels a day, more than 9 per cent of OPEC's output.
"Whatever sector you look at, companies will keep in mind being cut off from the US financial system when deciding whether to trade with Iran," said Mehdi Varzi, an independent oil consultant who has previously worked at the state-run National Iranian Oil Co.
Israel warned this month that its navy could take action against Iran, which it said was smuggling oil using clandestine measures similar to those employed during the previous round of sanctions.
According to maritime specialists, methods used for skirting sanctions in the past have included changing the names of ships, switching off AIS (Automatic Identification System) location transponders and conducting ship-to-ship transfers of oil.
Since the previous round of sanctions in 2012, ship tracking has become more sophisticated and more available. Washington has also cracked down on more Iranian networks, making it riskier to get involved with Iran, according to bankers.
Iran reached an agreement with world powers in 2015 over its nuclear programme which led to the lifting of sanctions in 2016 but Trump pulled out of the deal in May last year and reimposed US restrictions in November.
"Many big oil traders are very worried about going into Iran due to Trump, and even the Chinese are trying to comply with what the Americans want," said Varzi, who is based in Britain.
A senior Iranian official played down the threat to its oil exports because of pressure on its fleet.
"Plenty of countries are happy to do business with Iran," the official said. "As we have done in the past, there are several ways to overcome the shortage, including using tankers of other countries."
A second Iranian official said discussions with South Korea over the possibility of ordering as many as 10 supertankers, each able to carry up to 2.0 million barrels of oil, had been delayed by US sanctions.
"We are working on it," the official said.