Equivalent Circulating Density (ECD)

Equivalent Circulating Density, often abbreviated as ECD, refers to the density of the drilling fluid while the well is being circulated.

It takes into account the hydrostatic pressure exerted by the fluid column in the wellbore as well as the frictional pressure losses that occur during circulation while the drilling mud pumps are working.

Reference: Formulas and Calculations for Drilling Production and Workover, William Lyons, Tom Carter, Norton J. Lapeyrousse