DRILL MUD FOR PRIMARY OPENING OF PRODUCTIVE FORMATION Russian patent published in 2019 - IPC C09K8/08 

FIELD: oil industry.

SUBSTANCE: invention relates to water-based drill muds. Drill mud for primary opening of productive formation contains, wt %: biopolymer of xanthan type 0.25–0.35; modified starch 1–2; clay inhibitor based on a mixture of low-molecular glycols 1–3; polyethylene glycol 1–2; surfactant – composition of polyalkylene glycol ethers 1–3; composite nonionic surfactant 0.05–0.2; potassium chloride or potassium carbonate, or sodium formate, or sodium chloride 3–15; calcined soda 0.05–0.2; caustic soda 0.05–0.3; carbonate colmatant 5–30; lubricating additive 1–3; antifoaming agent 0.03–0.1; bactericide 0.05–0.1; water – balance.

EFFECT: technical result is increase of oil production rate due to reduction of interfacial tension on boundary of oil-filtrate of drill mud and thereby improving phase permeability for oil, maximum preservation of reservoir properties of productive formation and restoration of its permeability for oil and gas to potentially possible values with their preservation during time.

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