OIL-WELL FOAM CEMENT COMPOSITION Russian patent published in 2001 - IPC

FIELD: oil producing industry. SUBSTANCE: composition may be used applicable as oil-well foam cement composition in cementing of casing strings under conditions of abnormally low formation pressure and lost circulation, and in installation of separating bridging plugs in completion and testing of oil and gas wells with presence of formations with different pressures. Oil-well foam cement composition contains cement, additive in the form of sized glass microspheres, surfactant and water. Said composition additionally includes calcium chloride and sulfacell at the following ratio of components, mas. %: cement, 97.0-99.0; sized glass microspheres, 1.0-3.0; surfactant, 0.5-0.7; sulfacell, 0.3-0.4; calcium chloride, 3.5-4.0; water, 50.0. Composition provides for reduction of time of setting of foam-cement composition and preservation of stability with foam expansion ratio of 1.5-1.8 and density of 0.85-1.18 g/cu.cm. EFFECT: increased strength and reduced gas permeability of formed cement stone. 1 tbl