Drilling EngineeringDrilling Hydraulics
Annular Velocity from Pump Output Formula
Annular velocity from pump output estimates the average drilling-fluid velocity in the annulus from flow rate and annular area.
How engineers use this formula
Use it for hole-cleaning checks, hydraulics reviews, and circulation planning before more detailed rheology calculations.
Assumptions
- Flow rate is steady during the calculation.
- The annular area represents the section being evaluated.
- Velocity is an average value, not a local velocity profile.
Limitations
- Does not account for eccentricity, cuttings bed development, or non-Newtonian velocity profiles.
- Not a replacement for detailed hole-cleaning modeling in deviated wells.
Common mistakes
- Using pipe ID instead of annular area.
- Comparing average velocity directly to critical transport limits without considering inclination and rheology.
Default example
Using the default inputs, AV equals 311.111111 ft/min.
Qgpm
600
D_hin
8.5
D_pin
5
Inputs
Q
gpmCirculation Rate
D_h
inHole or Casing Inside Diameter
D_p
inPipe Outside Diameter
Outputs
AV
ft/min
Annular Velocity
Q
gpm
Circulation Rate
D_h
in
Hole or Casing Inside Diameter
D_p
in
Pipe Outside Diameter
Source and review
reviewedLyons, W.C., Carter, T. and Lapeyrouse, N.J. 2012. Formulas and Calculations for Drilling, Production and Workover, 3rd Edition, Page 10.
Source