Calculate annular velocity in ft/min from pump output and hole and pipe diameters or annular capacity, or solve for pump output or annular capacity.

Average fluid speed = pump output ÷ annular capacity. Capacity comes from the hole and pipe sizes, or enter it directly. 1 bbl = 42 US gal.

Optional settings

Annular Velocity Formula

The following equation is used to calculate the Annular Velocity.

AV = PO / AC
  • Where AV is the annular velocity (ft/min)
  • PO is the pump output (bbl/min)
  • AC is the annular capacity (bbl/ft)

Select Annular velocity, enter pump output, and either the hole and pipe diameters or a known annular capacity. Other solve choices find pump output, capacity from flow or diameters, or output from stroke rate and displacement. Each input has its own unit control; oil barrels are 42 US gallons.

What is an Annular Velocity?

Definition:

Annular velocity is the average linear velocity of a fluid (typically drilling fluid/mud) moving through the annulus—the space between the drill pipe (or casing/tubing) and the borehole (or outer casing).

How to Calculate ?

Example Problem:

The following example outlines the steps and information needed to calculate the Annular Velocity.

First, determine the pump output. In this example, the pump output is found to be 12.5 bbl/min.

Next, determine the annular capacity. In this case, the annular capacity is measured to be 0.25 bbl/ft.

Finally, calculate the Annular Velocity using the formula above:

AV = PO / AC

AV = 12.5 / 0.25

AV = 50 ft/min