INHIBITING DRILLING FLUID Russian patent published in 2020 - IPC C09K8/08 

FIELD: mining.

SUBSTANCE: invention relates to water-based drilling fluids and can be used in drilling oil and gas wells, in particular when drilling unstable clay rocks, as well as drilling horizontal wells and wells with high deflection angle. Inhibitory drilling fluid includes, wt. %: structure-forming biopolymer 0.2–0.5; water-soluble salt 3–30; polyDADMAC 1–5; chitosan 0.1–1; polyvinylpyrrolidone 0.1–1; water is the rest. Water-soluble salt used is potassium chloride, sodium chloride, sodium formate, potassium formate or mixtures thereof. Drill fluid can additionally contain carbonate microbridging agent in amount of 3–20 wt. % and starch reagent in amount of 1.5–3 wt. %. Carbonate microbridging agent used is marble chips, chalk or microcalcite.

EFFECT: technical result is providing high inhibiting properties, higher adhesion properties and improved operating characteristics of the solution.

5 cl, 2 tbl