HYDROCARBON-BASED DRILLING FLUID Russian patent published in 2021 - IPC C09K8/32 

FIELD: oil-based drilling fluids.

SUBSTANCE: invention relates to oil-based drilling fluids, intended for drilling appraisal, prospecting and exploration wells with coring, while maintaining its natural fluid saturation. Oil-based drilling mud includes, wt.%: lithium salts of naphthenic acids 3.7-14.0; calcium salts of naphthenic acids 0.8-3.0; synthetic acrylic copolymer 0.7-1.2; surfactant based on condensation products of fatty acids with amines 0.1-1; organophilic bentonite 0.45-1.80; fine marble 0.1-11; barite 0.1-60; the rest is the mineral oil.

EFFECT: reducing the effect of the drilling fluid on the water and oil saturation of the core of productive rocks while maintaining the stability of the drilling fluid at high density up to 1.83 g/cm³, maintaining the optimal filtration parameters of the drilling fluid under conditions of increased temperature and pressure, increasing the level of safety in the preparation and use of the fluid.

1 cl, 2 tbl