Saudi Oil Minister al Falih, who also ran ARAMCO, has been replaced by Abdulaziz bin Salman bin Abdulaziz al Sa'ud, half brother of Crown Prince Mohammed bin Salman bin Abdulaziz al Sa'ud, (MbS),who was Ambassodor to the US untile the Khahoggi murder got hot between USA and KSA.
The New York Times claims that this is part of an effort by MbS to modernize the Saudi economy, an ongoing line of th Saudi PR machine. However more specifically how al Falih got in trouble with MbS is that oil prices are too low and there has not yet been an IPO for ARAMCO. These probably are issues for MbS, although I think at this point the Saudi Oil Minister's ability to make oil prices go up has become limited. But the lack of an ARAMCO IPO clearly has cost variouis members of the Saudi royal family money. But the problem has been that to issue an IPO ARAMCO will have to make public information that apparently it does not want to. Whether MbS and his brother are really ready to do that is unclear.
Anyway, I think all this talk about modernizing is just baloney. This is just a further move to consolidate power and also make money for the Salmans, the king and his sons.