https://www.zerohedge.com/news/2018-07-30/chinas-oil-futures-contract-beginning-show-its-teeth
not so long ago, the only way to buy oil was using the USD, and countries that tried using other currencies are rumored to have been targets for disruptions and invasions,but china is to big and powerful to be bullied in this way, so it is likely that we are going to see the yuan finally come into it's own in terms of global use