Sort:  

They did create the petro cryptocurrency that is supposed to be attached to their oil reserves. Though judging by the lack of demand for it thus far, I don't think anyone actually believes that it is backed. Admittedly though I have not done much research on it yet.

https://en.wikipedia.org/wiki/Petro_(cryptocurrency)

From what I hear, it's actually still nearly impossible to get, so it's still sort of a chicken and egg problem. Many of them will likely use it when they can get it.

I know most exchanges are not trading it. In fact I am not sure of any that are, though I haven't looked at many in South or Central America.

Yes, first rhey create a token backed up by oil. Then they ask to buyers to have that coint to trade. Then, they change the US Dollars for Crypto or directly they change Petro or whatevercrypto they have for Bitcoin.

How can they prove or show that it is actually backed by oil?

How can the US prove that they have every dollar backed by gold?