APPARENTLY VISCOUS DRILLING MUD Russian patent published in 2003 - IPC

FIELD: oil and gas production. SUBSTANCE: invention relates to drilling fluids for boring and completing wells. Drilling mud containing nonpolar water-insoluble phase, emulsifier, acidic surfactant, water, hydrocolloid filler and alkanolamine (for neutralizing acidic surfactant), contains, as both said nonpolar water-insoluble phase and said acidic surfactant, unsaturated fatty acids with 14-18 carbon atoms; as said emulsifier, oil-soluble ethylene oxide/propylene oxide copolymers with ethylene oxide content at most 15 mol %; as said hydrocolloid filler, cellulose and starch derivatives selected from carboxymethylcellulose, carboxymethylhydroxyethylcellulose, polyanionic cellulose, hydroxyethylcellulose, carboxymethylstarch, carboxymethylhydroxyethylstarch; and, as said alkanolamine, mono-, di-, and trialkanolamines. Components are used in following proportions, wt %: nonpolar water-insoluble phase and acidic surfactant 0.2-0.7, emulsifier 15-20, filler 0.2-0.5, alkanolamine 0.5-1.5, and water - the balance. EFFECT: enabled preparation of highly structured gel systems without use of expensive biopolymer reagents and imparted aggregative stability under elevated medium mineralization conditions and antifoaming effect. 2 tbl, 3 ex