1.
n. [Drilling Fluids]
The effective density exerted by a circulating fluid against the
formation that takes into account the
pressure drop in the
annulus above the point being considered. The ECD is calculated as: d + P/(0.052*D), where d is the
mud weight (
ppg), P is the pressure drop in the annulus between depth D and surface (psi), and D is the
true vertical depth (feet). The ECD is an important
parameter in avoiding kicks and losses, particularly in wells that have a narrow
window between the
fracture gradient and
pore-
pressure gradient.