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