1. n. []

A mud in which the external phase is a product obtained from an oil, such as diesel oil or mineral oil.

See: aniline point test,  attapulgite,  brine,  bypassed mud,  calcium chloride,  calcium test,  Chenevert method,  chloride test,  coalescence,  colloid,  creaming,  diesel-oil mud,  dispersion,  drilling fluid,  electrical stability test,  fatty acid,  fatty-acid soap,  flash point,  hectorite,  high-pressure, high-temperature viscometer,  hydrophile-lipophile balance number,  hygrometer,  inhibit,  inhibitive mud,  interfacial tension,  invert-emulsion oil mud,  lignite,  oil-base mud,  oil-mud emulsifier,  oil/water ratio,  organophilic,  organophilic lignite,  pour point,  rheology modifier,  shale,  sheen test,  slurry,  surface tension,  suspended solids,  synthetic-base mud,  synthetic/water ratio,  water-in-oil emulsion

2. n. []

More generally, a mud system that has any type of nonaqueous fluid as the external phase. This definition would include the newer variety of oil muds that are more exactly defined as synthetic-base muds. Synthetic mud is analogous to oil mud.

See: diesel-oil mud,  invert-emulsion oil mud,  oil-base mud,  syn,  synthetic-base mud