FROTHING COMPOSITION FOR INCREASING OIL EXTRACTION OF STRATUM Russian patent published in 1996 - IPC

FIELD: oil and gas recovery. SUBSTANCE: proposed frothing composition contains (mass %): urea 1.5-4.0, nitrite of alkali metal or of alkaline-earth metal 5.2-13.8, acid 0.9-2.4, surfactant 0.2-1.0, ammonium hydrofluoride 2.8-7.6, water the rest. During hydrolysis of ammonium hydrofluoride hydrofluoric acid is prepared, the latter interacts with carbonate- and clay-containing rocks of the stratum. Slightly soluble in water fluorides of alkali and alkaline-earth metals enable to seal pores of said stratum which are more penetrable for water and steam. Said fluorides participate in saturation of solution with gases by additional liberation of gaseous nitrogen. EFFECT: increases oil recovery of the stratum. 2 tbl