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.

See: differential sticking,  dynamic filter press,  dynamic filtration,  filtercake,  filter medium,  filter press,  filtrate volume,  high-pressure, high-temperature filtration test,  low-pressure, low-temperature filtration test,  static filtration