Q & A > Question Details
Currently I'm doing pump test with water, I want to know what is the best way to compare the flow from the FT and the flow in the pump curve, the Flow Transmitters are set for hydrocarbon with SG of 0.65 but I'm doing the test with water which SG is 1. Do I have to correct the flow to HC flow at conditions or standard conditions in order to compare the flows with the curve?. How can I do that?
07/09/2015 A: Yongming Zhang, HQCEC, 13439348666@139.com
To set Qh is hydrocarbon flow rate in volume rate, Qw is water rate in volume rate, ρh is hydrocarbon density, and ρw is water density. I know your consideration is for protecting pump motor as transfering water instead of hydrocarbon, because the pump driving power is direct proportion to flow rate and density, the bigger density, the bigger driving power, the bigger motor power, it is possible to have a bigger power value than the rating motor power, that will damage motor, so we get the formulation as Qh*ρh=Qw*ρw, finally, we get as Qw=0.65Qh.
02/09/2015 A: Eric Vetters, ProCorr Consulting Services, ewvetters@yahoo.com
A centrifugal pump pumps a certain volume at a certain head. The actual volume pumped at a given value of head should normally be the same whether it is .65 1 SG. To figure out what your actual flow is, you would need to come up with a new meter factor to use with your flow transmitter for pumping water instead of oil.
Your discharge pressure when pumping water will be much higher than when pumping .65 SG oil. Your pump horsepower requirement will also be much higher when pumping water, so you better make sure your motor is big enough before trying this.