It could be possible but not eventually. There would be many things to consider for it to become a global currency.
Bitcoin now is able to used in an international currency but it can not spend it in offline method because there is not real coin as this moment, but i think bitcoin now is global currency which can be use it in online method.
First, Bitcoin needs to establish itself as a "currency". Right now only 2 or 3 countries recognize Bitcoin as a form of currency. The usage is also quite low, and daily transaction volumes amount to less than $10 million USD. Compare this to the forex volumes of hundreds of billions of USD for the major world currencies such as the US Dollar and UK Pound.
But the mere fact that a big amount like $10 million is a good start for bitcoin. It is still young so it will grow more in the coming months or years and I think we will somehow reach it near those price from major currencies.