Single Phase Simulation to solve predominantly Single Phase Pipelines 1

[gtzaki]

Hi guys/ladies

Some clients had requested for us to do some simulations on their upstream gas gathering network.
Their gas gathering network has been setup so that they have separators at the wellhead prior to transmission in the pipelines.
Also, they have Low Point Drains to knock out water in the system.

For something like this, we would usually just use a single phase simulation and fine tuning (by adjusting the effective roughness) to actual parameters.
However, they have requested that we use a multi phase simulator to solve their network issues.
From experience, this type situation does not call for a multiphase simulator.

So my question is whether has anyone come across literature which uses single phase simulation for this kind of case?
It would be good to find out:
a) is this a generally accepted practice.
b) what sort of correlation can we get for a given entrained water in the gas.
c) to what extent will the single phase model work (i.e. what limit of water entrained).

Appreciate hearing your thoughts on this..

Thanks,
z

 

[BigInch]

Your client is off on a space walk and left the O₂ in the module.
It is not accepted practice.

Most programs that run 1 phase do not correlate to handling entrained liquids. You will have to pretend it's dry gas.
Get them to get off the pot.
If you have that much water & liquids, you should not run 1 phase simulations. If you do, run 2 phase.

Check it. Assume all the water & liquids condense and check the resulting flow regime with your favorite 2 phase, steady state formulas. Check the gas to liquid ratios and resulting flow regime.

If you have anything other than mist or annular mist, or light slugging, without significant variation in predicted pressure drops that would leave you unable to clear liquids with maximum inlet pressures and minimum outlet pressures + safety factors, do a two phase, otherwise consider that all the condensates are knocked out at the scrubbers, drips, and slug catchers and treat the analysis as essentially dry gas. Keep your velocities near 1 m/s to keep condensate drops moving along to scrubbers, drips and slug catchers.

If they have wave flow, slugs with high pressure drops nearing 1/2 the max pressure differential capacity of the pipeline, or worse, sell them on a full 2-phase analysis.



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