The 24 nations in the supply-cut pact, known as Opec+, agreed in late 2016 to trim production by 1.8 million barrels a day but they have actually been keeping some 2.8 million barrels per day off the market.
OPEC's agreement with Russian Federation and other producers to limit oil output has helped to clear a global supply overhang that weighed on prices for years.
This was a reversal of years of rising production and falling prices, which many saw as an attempt by Saudi Arabia and others to create an oil glut to discourage investment in USA shale oil production.
Iran, OPEC's third-largest producer, had demanded OPEC reject calls from Trump for an increase in oil supply, arguing that he had contributed to a recent rise in prices by imposing sanctions on Iran and fellow member Venezuela. That means Friday's agreement will end up adding about 600,000 barrels of oil a day to the global market. Alongside this, the increase in output will likely be easily absorbed by the market and is not going to tip the oil balance into negative territory, which could allow for oil prices to grind higher.
The output boost agreed on Friday had been largely priced into the market and was seen as modest. Iran, for example, has been hit by US sanctions that hinder its energy exports. "Oil is the bigger story today with the OPEC news". "We're taking our breath and focusing on the oil market", said Ryan Detrick, senior market strategist at LPL Financial in Charlotte, North Carolina.
He also warned the world could face a supply deficit of 1.8 million bpd in the second half of 2018 and that it was OPEC's responsibility to alleviate consumers' concerns.
"We want to prevent the shortage and the squeeze that we saw in 2007-2008", Falih said, referring to a time when oil rallied close to $150 per barrel. Venezuela's production has dropped amid domestic political instability.
"Both Saudi and Iran can show that they won", an OPEC delegate said. The next formal OPEC meeting was set for December 3.