Annular velocity

Annular Velocity is the speed of a fluid's movement in a column called an annulus in wells being drilled with circulating drilling fluid. It is commonly measured in feet per minute (ft/min) or meters per minute (m/min). Annular velocity is often abbreviated as AV, though this is not exclusively so, as AV also refers to apparent viscosity which is calculated from rheometer readings from tests that the mud engineer performs.