1. n. [Drilling Fluids]

A finely divided, solid material, which when dispersed in a liquid medium, scatters a light beam and does not settle by gravity; such particles are usually less than 2 microns in diameter. Some drilling fluid materials become colloidal when used in a mud, such as bentonite clay, starch particles and many polymers. Oil muds contain colloidal emulsion droplets, organophilic clays and fatty-acid soap micelles.

See: anion,  calcium contamination,  clay extender,  clay-water interaction,  colloidal solids,  colloidal suspension,  dispersion,  hydration,  micelle,  oil mud,  oil-mud emulsifier,  peptize,  peptized clay,  peptizing agent,  polymer,  prehydration,  silt