Multi-Phase Pumps (Subsea)

[RandomAxe]

I am currently looking into the possibility of including a subsea multi-phase pump into a 4 well tie-back (15km tieback to host manifold). Downhole ESPs have already been ruled out, so the remaining options are a twin srew pump (TSP) or a helico axial pump (HAP). What would generally be the governing criteria in selecting between the two? From research I have done so far:

Both will operate at 100% Maximum GVF
Helicoaxial will generate larger differential pressure
Twin screw total capacity can be more than double that of equivalent helicoaxial
Twin screw will work with a higher viscosity fluid
Helicoaxial are generally rated to higher pressures (15k)

Are there any other criteria I am missing? Any additional information? Thanks

 

[DubMac]

DOn't forget to look at solids handling capability; specifically small amounts of sand. Take a look at operating clearances and the materials or coatings offered for abrasion control.
Also look at slug handling capabilities for both. I would say that the twin screw probably has many more installations, but not sure.

 

[ApplicationENG]

Fluid Characteristics (gas content, solids, temperature), Reliability. I agree with DubMac in that there are more twin-screw installations. You could ask an OEM and ask them to avoid the sales pitch for pros and cons. Bornemann is pretty good, so is Leistritz

 

[RandomAxe]

Thanks for the responses guys, some useful information.

Interestingly, from doing research into subsea processing capabilities it appears that helico-axial pumps have been used more extensively subsea to date, Ref Worldwide Survey Subsea Processing 2013:

http://www.offshore-mag.com/content/dam/offshore/maps-posters/SubseaBoosting-022113.pdf