METHOD OF PREPARING LIGHT-WEIGHT GROUTING MORTAR Russian patent published in 2001 - IPC

FIELD: oil and gas production. SUBSTANCE: invention relates to cementation of casing strings under conditions of abnormally low formation pressures and presence of corrosive media. Grouting mortar is prepared by mixing grouting Portlandcement with tempering fluid. The latter is suspension containing, wt %: sulfacell 0.3-0.5, calcium chloride 2.0-5.0, superplasticizer 0.3-0.4, microspheres 5.0-7.0, and water 54.0-68.0. Fluid is prepared by preliminarily preparing aqueous solution containing sulfacell, calcium chloride, and superplasticizer, followed by adding microspheres. Resulting suspension is used to temper grouting cement. EFFECT: increased strength of cement stone and reduced specific gas permeability upon hardening at normal and moderate temperatures. 1 tbl