1. n. [Drilling Fluids]

A chemical used in preparation and maintenance of an emulsion mud, which is a water mud containing dispersed oil (or a synthetic hydrocarbon). Numerous types of emulsifiers will disperse oil into water muds, including sulfonated hydrocarbons, ethyoxylated nonylphenols, alkali-metal fatty-acid soaps, lignosulfonate, lignite and lignin at high pH. Even clays, starch and carboxymethylcellulose aid emulsion mud stability. Reference: Rogers WF: "Oil-in-Water Emulsion Muds," in Composition and Properties of Oil Well Drilling Fluids, 3rd ed. Houston, Texas, USA: Gulf Publishing Company, 1963.

Synonyms: water-mud emulsifier

See related terms: emulsion,  interfacial tension,  soap,  synthetic-base fluid