EMULSION DRILLING MUD Russian patent published in 2021 - IPC C09K8/02 

FIELD: drilling.

SUBSTANCE: invention relates to drilling and completion of oil and gas wells, in particular to emulsion drilling muds. The emulsion drilling mud contains an oil phase, salts of alkaline and/or alkaline earth metals, organophilic bentonite, a polar phase and an emulsifier. As the oil phase, alkyl esters of fatty acids of vegetable oils and/or mixtures thereof in an amount of 50-90 wt.% are used. As the polar phase, water and/or polyatomic alcohol, and/or monoethanolamine, and/or diethanolamine, and/or triethanolamine in an amount of 0.1-47.9 wt.% are used. As an emulsifier, a composition of nonionic surface active agents in an amount of 0.1-10 wt.%, organophilic bentonite in an amount of 2-3 mass.% and salts of alkaline and/or alkaline earth metals in the amount of 0-20 wt.% are used.

EFFECT: production of an emulsion drilling mud, which provides increased efficiency of sludge transport when drilling inclined and horizontal shafts under conditions of abnormally low reservoir pressure, high electrical stability and sedimentation stability, as well as the stability of the protective adsorption barrier at the interface.

5 cl, 2 tbl, 3 ex