Not sustainable at all.
The Saudis and Russians have often noted that they are not obligated to sell their product at a price defined by institutions in enemy countries — meaning NYMEX and LSE.
They will sell crude at a price determined by refiners. And as has been true for decades, if refiners demand too low a price, Saudi Aramco and Rosneft both can say no and offer to other refiners willing to pay more.
In the end, oil is civilization’s lifeblood. You HAVE to have it. There is no discretion and there is nowhere to go to replace that 20% of global production if Aramco and Rosneft say no.
Historically, the Saudis have determined what price will be as high as they can make it without eroding the western economies — which would lower their oil consumption. It is not determined by guys in NY and Chicago doing buys and sells of commodity contracts.