Definition(s)
Equivalent Circulating Density
The effective density of the circulating fluid in the wellbore resulting from the sum of the pressure imposed by the static fluid column, friction pressure and surface back-pressure.
Source: ABS Guide for Classification and Certification of Managed Pressure Drilling Systems, September 2017. Global Standards
Equivalent Circulating Density (ECD)
Equivalent circulating density is the effective density of the circulating fluid in the wellbore resulting from the sum of the hydrostatic pressure imposed by the static fluid column and the friction pressure.
Source: API STD 65 – Part 2, Isolating Potential Flow Zones During Well Construction, Upstream Segment, Second Edition, December 2010. Global Standards
Equivalent Circulating Density (ECD)
The sum of pressure exerted by hydrostatic head of fluid, drilled solids, and friction pressure losses in the annulus divided by depth of interest and by 0.052, if ECD is to be expressed in pounds per gallon (lb/gal).
Source: API RP 59, Recommended Practice for Well Control Operations, Second Edition, May 2006. Global Standards