Prince Khalid bin Salman, their younger brother, is effectively in charge of the defence ministry.
Sources from the energy ministry were quoted as saying that the prince's lengthy experience has overcome what has always been seen as the impossibility of appointing a royal to the post of energy minister in Saudi Arabia, according to Gulf News.
"I think it is a positive notion to the market that a person like Prince Abdulaziz is taking [the oil ministry] with all of that history of OPEC that he has", said Suhail Al Mazrouei, minister of energy for the United Arab Emirates.
In his 20s he became an advisor to the energy ministry in 1985 before being named deputy oil minister in 1995, a position he held for nearly a decade. He was named deputy oil minister in 1995, a position he held for almost a decade.
"Prince Abdulaziz is a very seasoned veteran of Saudi and OPEC policy-making". The Saudis are doing the most to support the deal, pumping about 500,000 barrels a day less than they pledged.
Al-Falih was already walking the plank.
His ouster comes simply days after he was eliminated as chairman of Aramco, as the corporate prepares for a much-touted preliminary public providing (IPO). It signaled a possible rift with the crown prince over his management of various issues, including reportedly moving too slowly in advancing Prince Mohammed's plan to sell shares in the state-owned oil company Aramco.
"The Prince has been a key shaper of Saudi oil and OPEC policy for many years", said Fattouh, adding that he has also been a key player in domestic oil policy such as the kingdom's energy pricing reforms, renewables and energy efficiency. "He joined the oil ministry in the late 1980s and worked closely with the three previous oil ministers", stated Ali Shihabi, founding father of the now-shuttered pro-Saudi think-tank Arabia Basis.
Since his appointment as oil minister in 2016, Falih has been the face of Saudi power coverage however the veteran technocrat had seen his portfolio shrink in current weeks.
Al-Falih's decreasing role had contributed to reports he had been out of favour with the crown prince, who's pushing to diversify the Islamic economy from its reliance on petroleum revenue for success.
To maintain oil prices from slipping even farther, he led Saudi Arabia's curb on manufacturing from OPEC and the petroleum cartel's arrangement with other significant oil producers, such as Russian Federation, to reduce production in previous decades.
The Kingdom additionally changed the deputy power minister, SPA added.