1. n. [Drilling Fluids]
A clay-based, water mud that has had its viscosity reduced with a chemical treatment; incorrectly, called a "dispersed" mud. The chemical used is a deflocculant, not a dispersant. A well-known and effective clay deflocculant is lignosulfonate. The mud, after being deflocculated, usually shows much improved filter-cake qualities with lower yield point and gel strengths. Filter-cake quality is improved because when clays are deflocculated, the platelets become detached from each other and can lie flat to form a thin, low-permeability filter cake. Lowering yield point and gel strength may not always be desired and can be adjusted by the amount of deflocculant added in each treatment. If yield point and gels are lowered too far, suspension and cutting capacity of the mud are impaired.