MAGNESIA-BASED GROUTING MIXTURE Russian patent published in 2025 - IPC C09K8/467 

FIELD: oil and gas industry.

SUBSTANCE: invention relates to oil and gas industry, namely to primary cementing of casing strings in oil, gas and gas condensate wells with maximum static temperature of 100 °C, exposing thick strata of highly mineralized salts of chlorine-magnesium type, formations with abnormal pressures prone to hydraulic fracturing and losses, as well as rocks containing aggressive fluids and gases. Magnesia-based grouting mixture containing binder, magnesia-silica additive, complex of chemical modifiers and tempering fluid. Binder used is no-additive portland cement, and the magnesia-silica additive is heat treated at temperature of 1,020-1,050 °C finely ground serpentinite-containing rock, and the complex of chemical modifiers is sodium lignosulphonate and sodium gluconate; the tempering fluid is high-mineralized water based on sodium chloride with density of 1,180-1,200 kg/m³ with water-mixture ratio of 0.45-0.55, in the following ratio of components in % by weight: no-additive portland cement 51-56.9, magnesia-silica additive 39.6-47.8, sodium lignosulphonate 1-3, sodium gluconate 0.2-0.5.

EFFECT: creation of a grouting mixture on a magnesian basis, which during hydration forms a grouting mortar with high sedimentation stability, with controlled thickening-setting time at temperatures of 50-100 °C, and during hardening – water- and corrosion-resistant backfill stone of high strength.

1 cl, 2 tbl, 4 ex