HIGHLY INHIBITED CLAY-FREE EMULSION DRILLING MUD Russian patent published in 2019 - IPC C09K8/28 

FIELD: soil or rock drilling.

SUBSTANCE: invention relates to drilling and construction of wells. Clay-free emulsion drilling mud for drilling wells in complex mining and geological conditions, wells with abnormally high and abnormally low formation pressure, as well as for primary opening of productive reservoirs contains the following, wt%: biopolymer of xanthan type 0.15–0.29; modified starch 1.4–2.5; carbonate weighting agent – microcalcite with particle size of 5–100 mcm 1.0–12; hydrocarbon base – a mixture of oligomerization products of olefins, mineral distillate and residual base oils of "Neoinvert Oil" grade 12.5–17.3; emulsifier based on "NeoInvert K" fatty acids 0.8–1.2; polysaccharide polymer inhibitor and heat stabilizer – potassium formate 0.5–25; inhibitor of swelling of clay materials – a mixture of polyglycols and aliphatic amides with weakly cationic properties of "Ingidol A" 0.5–0.73; pH regulator – sodium hydroxide 0.1–0.25; antifoaming agent 0.07–0.1; bactericide 0.04–0.1; water – balance; barite concentrate as additional weighting agent to density of 1,400–1,500 kg/m³ in excess of 100 wt%.

EFFECT: increased drilling speed and driving to bit, reduced time of well construction, environmental safety, high tribotechnical properties, low filtration properties, high thermal stability, high stability of solution in time.

3 cl, 4 tbl