1. n. [Drilling Fluids]

A test to measure static filtration behavior of water mud at ambient (room) temperature and 100-psi differential pressure, usually performed according to specifications set by API, using a static filter press. The filter medium is filter paper with 7.1-in2 filtering area. A half-size cell is sometimes used, in which case the filtrate volume is doubled.

See: filtercake,  filter medium,  filtrate,  low-pressure, low-temperature filtration test,  relative filtrate volume,  spurt loss