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two phase pressure drop

two phase pressure drop

two phase pressure drop

(OP)
I have to perform the two phase pressure drop for the oil flowing from the wellhead to the inlet manifold at the station via the choke valve and manifold.

known data are flow rate, wellhead flowline presssure and temperature and water cut.
Seeking help to the do the above

RE: two phase pressure drop

I would recomend using PipeSim 2000. This is a good program that can handle multiphase flow and allows you to set up complex systems easily. This though is probably q relatively expensive program to buy if you are just looking for a one off calculation. They might well offer a trial version or do it for you on a consultation arrangement. See site

http://www.sis.slb.com/content/software/production/pipesim/index.asp?seg=www%2Ebakerjardine%2Ecom&

for information

RE: two phase pressure drop

In my opinion a better product for this is PipePhase ( published by SimSci).  It properly handles the blackoil correlations for viscosity and thermal/transport properties and it's forte is two-phase fluid flow.  It is expensive.  Best thing to do is hire a consultant who already has the software.  I can name one or two if you need it.  Pete

Thanks!
Pete

RE: two phase pressure drop

To me it doesnt matter which simulation program; Pipephase or Pipesim.  It is who's correlation that counts.  Many select OLGA correlation.

But for simple hand calculation, use "Duckler" corelation.  Not so accurate but go enough for design purpose.

RE: two phase pressure drop

  
Hi,

    To what 2-phase flow packages do you have access?
Pipephase, Pipesim and OLGA can do the job. However, should
you plan to build your own routine, I would  suggest you to
use Beggs & Brill correlation for horizontal and near
horizontal 2-phase flows). A bit more complicated approach
would be writing routines for mechanistic models.

    Also, there are several correlations to calculate flow
of complex G-L mixtures through restrictions, but make sure
to check whether the flow through the choke is critical.

Hope that helps. Good luck!

---Fausto

RE: two phase pressure drop

The problem with Beggs and Brill, Dukler, L&M, etc. for this particular application is they have no capability to deal with the oil-water physical and bulk properties, e.g. the oil viscosity or the emulsion phase viscosity.  They assume a homogeneous liquid phase, which of course gross production is not.  The best correlation is OLGA or one of the blackoil models embedded in PipePhase.  These will get you a MUCH better ESTIMATE of the situation.  And even then your calculated value will be ±20% at best.

I guess I would disagree about using Dukler or BBM for design purposes.  I have done this exact work a ton of times and speak from experience.  BBM, Dukler, etc. will get you a number for dP but you may be WAY off due to the reasons cited above.  In my practice I would never use one of those for a gross production stream UNLESS I had bulletproof lab and/or field data that showed (1) there was virtually no emulsion phase (2) the tendency to form an emulsion is small (3) the nature of the liquid phase flow is well-known, i.e. oil-water slug or plug flow, or oil-water stratified.

If your need is critical I would find a consultant who has the Pipephase software.  You should be able to get this calculation done for a few hundred bucks.

Thanks!
Pete

RE: two phase pressure drop

Duuuhhhh, I should have continued my post...  For this discussion we will assume your boss is beating on your door and wants a 10-minute solution.

If you want a WILD guess for the answer, go ahead and use Dukler or BBM for the dP correlation.  You can conservatively bracket the solution by assuming that the liquid phase is 100% crude oil since it has the higher viscosity of the two liquids.  Run your calc and get your dP/velocity/pipe size answer.  

Now, take that crude viscosity number and increase it by 1.5x to assume the liquid phase is 100% emulsion since typically crude-water emulsion viscosities are about 1.5x-2x that of crude oil.  Now run your dP calc again and select a different pipe size if needed.

Thanks!
Pete

RE: two phase pressure drop

Pete is correct in that the presense of emulsions can significantly affect the bulk liquid viscosity thereby increasing the pressure loss in the flowline considerably.  Fortunately, PIPESIM allows users to apply the Woeflin correlation to calcuate the oil-water emulsion viscosity used for any flow correlation.

If you are using the OLGA steady state correlation with either PIPESIM or PipePhase, keep in mind there are 2 versions of this correlation - the most common used one being the OLGA 2-phase which treats the oil and water as a homogeneous liquid.  OLGA 3-phase accounts for slip between the water and oil.

Hope this helps!
Mack


RE: two phase pressure drop

I would recommend WinSim. it has most of the correlations mentioned above.

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