DRY MIXTURE FOR PREPARING EXPANDING GROUTING MORTAR Russian patent published in 2020 - IPC C09K8/467 E21B33/138 C04B28/04 C04B24/24 C04B16/04 C04B14/38 

FIELD: oil industry.

SUBSTANCE: invention relates to oil and gas industry, in particular, to dry mixtures for preparation of expanding grouting mortar used in well cementing. Dry mixture for preparing expanding grouting mortar contains portland cement, ultra-cement, sodium boron hydride commercial-grade, sulfacell, additive for concrete and mortar of polyfunctional action "PFM-NLK", Policem Defom, additive for reduction of water-gas permeability of cement stone by Policem Gazblock, and polypropylene fiber with fiber length of 6–8 mm, diameter of 18 mcm at following ratio of ingredients, wt%: portland cement 78.40–81.85, Ultracement 9.09–19.77, sodium boron hydride commercial-grade 1–7, sulfacell 0.3–0.5, additive "PFM-NLK" 0.3–0.5, Policem Defom 0.1–0.5, Policem Gazblok 0.1–0.5, polypropylene fiber with fiber length of 6–8 mm, diameter of 18 mcm 0.03–0.06.

EFFECT: higher quality of cementing of casing strings due to increased strength of adhesion of cement stone to casing string and rock, which prevents leakage of columns and inter-formation overflows during operation, production of non-caking, non-clumping, high stability dry mixture and expanding grouting mortar from said dry mixture with improved structural-rheological properties, high gas-blocking properties, providing formation of cement stone with high strength and obtaining a close contact of cement with rock and casing by increasing the intensity of action of expanding additive, expanded assortment of reagents, reduced time and simplified technology of preparing expanding grouting mortar; saving transport costs.

1 cl, 2 tbl