Choke/Orifice Sizing

[BrettARichard]

How would i go about selecting the correct choke to create a 600 psi pressure drop with a pump rate of 2 bpm.

The inlet pipe i.d. is 2". Thanks.

 

[israelkk]

How much is the pressure before the orifice?
Do you mean 2 GPM?
What is the fluid media?

 

[BrettARichard]

I actually worded that one wrong. Sorry. We will be choked down to 1" from 2" id inlet. I need to figure out what rate to pump to create a 600 psi pressure drop. Thanks for the quick response.

 

[israelkk]

What are you pumping? oil? water? air?

 

[BrettARichard]

it is actually a water-based crosslinked fluid. 8.5 pounds/gallon with a viscosity of approximately 300 cent.

 

[DrillerNic]

The equation I have for liquid flow through a choke is:

Flow rate = C * Cd * D * Sqrt(Pressure drop/liquid density)

C is a constant depending upon units (bpm, 64ths, psi, ppg etc).
Cd is a choke co-efficent supplied by the manufacturer for different bean sizes & Reynolds number

For a choke to work, the flow through it must must be critical, which is generally taken as Pressure upstream / pressure dopwnstream is greater than about 2.

 

[zdas04]

BrettARichard,
Be really careful designing anything for pumping a cross-linked gel using the standard correlations. These corelations are generally based on Newtonian fluids and cross-linked gels rarely have a linear stress vs. strain relationship. Many of them behave like Bingham plastics (i.e., like toothpaste they behave more like a solid than a liquid until the strain reaches a certain point, then they flow like a Newtonian fluid).

You probably have already thought of all of this, but I just wanted to raise this point. I've seen several poor-boy frac operations get into trouble when the field guys put in a pipe choke that wasn't in the original design and caused the system to be on the wrong side of some stress-strain curve.

David Simpson, PE
MuleShoe Engineering

http://www.muleshoe-eng.com

Please see FAQ731-376 for tips on how to make the best use of Eng-Tips Fora.

The harder I work, the luckier I seem

 

[Latexman]

DrillerNic,

For a choke to work, the flow through it must must be critical, which is generally taken as Pressure upstream / pressure dopwnstream is greater than about 2.

This sounds like the rule of thumb for a gas or vapor to me. You may want to re-check this. The OP is asking about a liquid.

Good luck,
Latexman