Another head scratcher...

We all know that oil and water will not mix. If you can get it to mix it wont stay mixed for long. Right? Right.

So what happens when you mix Argon and Helium inside the bottle?
Would logic not dictate that Argon sink to the bottom and Helium float to the top of the bottle even though they are under pressure. For the same matter what about CO2 and Argon or any other gas mix out there.