1. n. [Drilling Fluids]

A group of mud additives specifically designed to lower the volume of filtrate that passes through a filter medium. Specific materials are available for all types of water- and oil-base mud systems and are evaluated in static filtration tests or in various dynamic filtration tests.

See: dynamic filter press,  dynamic filtration,  filter medium,  filtrate volume,  fluid-loss control,  high-pressure, high-temperature filtration test,  low-pressure, low-temperature filtration test,  oil-base mud,  static filtration,  water-based drilling fluid