That's fine. That means Chinese imports become more expensive and China loses money. As far as oil goes the PetroYuan isn't going to help them much – the Iranians aren't going to sell them oil at a 1 PetroYuan=1 USD rate. 1 Yuan=16¢IS currently.so the price will be adjusted for the PetroYuan's value against the USD, Euro, GBP, etc.
Another thing the Chinese will have to fear is nationalization. The U.S. Could pass a law stating that no foreign national canons real estate in the U.S. or they have to pay a heavy tax to do so.