It has been reported that Saudi Arabia is entertaining the idea of pricing its oil in yuans. Pricing oil in yuans would tremendously undermine the US petrodollar and could even knock off the dollar as a reserve currency. Currently, the majority of oil is bought and sold using dollars. This forces countries to hold large amounts of dollars in their banks in order to purchase oil, which props up the dollar as the ultimate de facto world currency.
Many OPEC countries have talked about using gold or other alternatives currencies instead of dollars but are met with great resistance. China understands this issue and has worked to set up an alternative system to the petrodollar: the petroyuan.