FOAMED PLUGGING COMPOUND Russian patent published in 1997 - IPC

FIELD: mining industry. SUBSTANCE: this is used in drilling oil, gas, and geological-prospecting wells for isolation of permeable reservoirs, stabilization of weak rocks and loose ground. Foamed plugging compound has nitrite of alkali metal or alkali-earth metal, sodium nitrite, gas-producing matter - urea, initiator of chemical reaction - acid, surface-active agent - sulfanol, and water. Additional components are bentonite clay and water-soluble polymeric compound - polyacrylamide. As gas-producing matter use is made of urea or its salt and their N; N, N' - derivatives, ammonia or its salt, as initiator of chemical reaction - any acid or acid salt - Lewis-type acid - iron chloride (III) at following ratio of components, mass %: nitrite of alkali or alkali-earth metal 2.8-67.2; gas-producing matter 1.2-29.2; initiator of chemical reaction 0.2-34.2; filler 0-30.0; surface-active agent 0.1-1.5; water-soluble polymeric compound 0.1-1.5; water - the balance. Water-soluble polymeric compound enhances stability of plugging compound and allows for formation of bars, granules, etc. Filler improves blocking of bottom-hole zones of absorbing beds, cuts well repair and development periods. EFFECT: high efficiency. 3 cl, 4 tbl