1. n. [Drilling Fluids]

The volume of mud filtrate measured after 30 minutes in API static filtration tests. The volume and cake thickness are the two data points in the test.

See related terms: dynamic filtration,  filtercake,  filter medium,  filter-cake thickness,  fluid-loss control,  fluid-loss-control material,  high-pressure, high-temperature filtration test,  low-pressure, low-temperature filtration test,  relative filtrate volume,  spurt loss,  static filtration