Q: I’m running a multiphase case with an IPR, and as I try calculations with higher flow rates, the calculated pump speed gets extremely high. Why?

A: When you specify a higher flow rate and you have an IPR active, PC-PUMP uses a lower pressure at the perforations (as defined by your IPR). At lower pressure, more gas comes out of solution before entering the pump. The free gas reduces the amount of volume within the pump occupied by liquid. PC-PUMP calculates pump speed based on the efficiency you’ve specified, the liquid flow rate you’ve specified, the proportion of the volume filled by liquid, and the pump displacement. As the amount of gas increases, the pump must run at a higher speed to achieve the liquid flow rate you’ve specified. This is indicative of a problem you would encounter in trying to pump off a gassy well by increasing the pump speed—you may find that above a certain speed you get very little incremental liquid flow rate.

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