LIGHT-WEIGHT GROUTING MORTAR Russian patent published in 2003 - IPC

FIELD: grouting mortars applicable in cementing of casing strings of gas, gas-condensate or oil wells complicated by presence of rocks poorly coherent, prone to hydraulic fracturing, with low positive or subzero temperatures. SUBSTANCE: light-weight grouting mortar includes oil-well portland cement, lightening additive in the form of inorganic hollow microspheres, expanding component and 4-% aqueous solution of calcium chloride. Inorganic hollow microspheres contain aluminosilicate microspheres in the form of product of separation of thermoelectric plant ashes. Expanding component is used in the form of ground slaked lime with content of nonslaked grains not more 15%. Light-weight grouting mortar contains the following ratio of components, wt.%: oil-well portland cement, 45.5-49.6; aluminosilicate microspheres, 6.2-9.1; ground slaked lime, 5.0-8.75; 4-% aqueous solution of calcium chloride, the balance. Technical result of use of invention consists in prevention of interstring flow in the course of construction and operation of wells due to improved parameters of grouting mortar, particularly, efficient expanding of cement stone at low positive and subzero temperatures at early stage of hardening with simultaneous reduction of grouting mortar density. EFFECT: higher efficiency of use. 1 tbl