Show me some proof they're charging higher prices to them, as they're constrained by who can refine heavy sour. Right now CITGO could and are we shipping to them and how much are we charging? That doesn't do anything to China's nuts as far as I can see, that appears to be all guesswork on your sources part.

Oil is sold on the open market for $x a barrel. Anyone can buy "non sanctioned" oil at this price.

But let's say I'm Nefarious Refining, Inc. and I don't want to pay that. I make contact with Sanctioned Country A and ask them to sell me some oil. But that transaction carries some risk: if I get caught buying oil from Sanctioned Oil A then it might get fined or jailed or make my company look bad. There are other risk items: Sanctioned Country A has to use these Ghost Fleet tankers to ship stuff and since they're illegal as well they might get intercepted by a NATO navy -or- these rust buckets might break down at sea. So my shipment might get seized or delayed. That's more risk of uncertainty around my shipment that I have to bear.

So I want a discount for the risk I'm taking - I'm not going to pay full price; to make it worth the risk I'm bearing Sanctioned Country A is going to have to cut their pricing by a lot.

China, India and the other unscrupulous outfits buying Blood Oil from Russia, Iran and Venezuela are benefiting from these discounts.

With Maduro gone the Venezuelan oil won't be sanctioned any longer...and China now gets to pay the market rate.