NON-CLAY STRONGLY ALKALINE DRILLING MUD WITH HIGH BRIDGING PROPERTIES FOR DRILLING IN HARSH ENVIRONMENTS Russian patent published in 2019 - IPC C09K8/10 

FIELD: oil and gas industry.

SUBSTANCE: invention relates to the oil and gas production industry, namely, drilling in conditions of bacterial, hydrogen sulfide and carbon dioxide aggression, including the construction of wells in the Far North and the continental shelf. Technical result is the decomposition of hydrogen sulphide, both natural and biogenic, to relatively harmless compounds for the purpose of safe and trouble-free well wiring, colmatation of reservoirs containing H₂S and CO₂. Drilling mud contains, by weight: Duovis biopolymer 0.1–0.3; cellulose PAC-R 0.1–0.3; cellulose PAC-LV 0.2–0.3; modified starch Dextrid 0.3–0.5; Defoamer 0.1–0.2; calcium oxide CaO 0.2–0.4, water the rest.

EFFECT: technical result is the decomposition of hydrogen sulphide, both natural and biogenic, to relatively harmless joints for the purpose of safe and trouble-free well wiring, reservoir colmatation.

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