Drilling fluid and method for increasing drilling speed.

摘要

An oil-in-water emulsion comprises an emulsion of oil (A) in water, an oleophilic colloid (B) being dispersed in the oil phase. The oil phase may constitute from 0.5% to 5.0% by weight of the emulsion and the colloid may constitute from 5% to 70% by weight of the oil phase. An emulsifier (C) may be used in amount from 0.1% to 1% by weight of the emulsion, and an inorganic salt (D) may be present in the water phase in amount at least 5% by weight of the emulsion. Oil (A) may be diesel oil. Colloid (B) is preferably asphalt. Also exemplified are oil-dispersible bentonite, methacrylic polymer, polyisobutylene, dimethylpolysiloxane, oil-dispersible lignite and carbon black. Emulsifier (C) may be polyoxyethylene, polyoxyethylated sorbitan tall oil ester, polyoxyethylated phenol, cetyl pyridinium bromide, monoalkyl quaternary amine, ethoxylated quaternary amine, amines and ethoxyphenol, tall oil and sodium hydroxide, naphthenic acid + sodium hydroxide, alkaryl polyether alcohol, lecithin, rosin + fatty acid soap, polyoxyethylene polypropylene, metal lignosulphonates + sodium hydroxide, lignite + sodium hydroxide, Quebracho + sodium hydroxide, (and see below). There may also be present in the emulsion 0.1 to 1% of a non-ionic colloid deposition retarding agent (E), for example an alkyl phenoxy polyalkylene glycol, optionally together with aliphatic and aromatic amines. If (E) is used, emulsifier (C) may be a tetraalkyl ammonium halide.