1.
n. [Drilling Fluids]
A term that is generally synonymous with
drilling fluid and that encompasses most fluids used in
hydrocarbon drilling operations, especially fluids that contain significant amounts of suspended solids, emulsified water or oil. Mud includes all types of water-base, oil-base and synthetic-base drilling fluids. Drill-in,
completion and
workover fluids are sometimes called muds, although a fluid that is essentially free of solids is not strictly considered mud.