If a higher pressure gas in introduced into one side of a pressurized pipe, would gas bubble through the liquid or displace the liquid? Assume the gas is at higher pressure than the liquid in the pipe and pipe is closed on the other end.
If the pipe is closed off at the other end, gas will bubble through and collect at the high point of the pressurised pipe. Bubbling will stop when the gas pressure at the high point equals pressure of of the HP gas.
Just to be clear: The gas and the oil will have the same pressure - although what you meant was propably that the gas source has a higher pressure?
And the gas is a hydrocarbon (not air, N2 or similar "inert")
One last thing: The pressure may be above the citical pressure of the oil/gas mix - then its even more complicated...
In this two option exists as i see it:
In both cases some of the might dissolve in the oil. But at a certain stage the oil will be saturated and free gas starts to form
1): Oil can be pushed ut by the gas as the gas enters the volume occupied previously by the oil. As others have noted it will tend to move to high places
2) Oil cannot be pushed out - gas will still enter but total pressur start to increase. This will make the effective volume of gas smaller (more gas will dissolve and the volume gas gas reduces as the pressure goes up). This will continue until the upstream gas pressure is reached.