1. n. [Drilling Fluids]
A measurement of the thickness of the filtercake, usually recorded in 32nds of an inch. Under dynamic conditions, filtercake thickness depends on rate of deposition versus erosion caused by fluid circulation and mechanical abrasion by the rotating drillstring. Typically, the filtercake will reach an equilibrium thickness in the wellbore. In laboratory tests, however, filtercake is built under static conditions with no erosion.
Synonyms: filter-cake thickness