METHOD OF TREATING BOTTOM-HOLE ZONE WITH FOAM SYSTEMS FOR RESTRICTION OF WATER INFLOW Russian patent published in 2002 - IPC

FIELD: oil and gas producing industry; applicable in treatment of bottom-hole zones for reduction of productivity coefficient of water-permeable interlayers. SUBSTANCE: method includes injection of aerated aqueous solution of surfactant with aeration ratio of not less than 4.5 under formation conditions; forcing of said composition into formation under pressure of not below the difference of 1.7 Pf-Ph, where Pf is formation pressure, and Ph is hydrostatic pressure. Water of high hardness is used fro preparation of aerated aqueous solution. Added to said water is equimolar amount of sodium carbonate for water softening and precipitation of carbonate salts into solid phase used for stabilization of foam. Surfactant is added to water after its circulation with sodium carbonate and neutralization of hardness cations. EFFECT: higher efficiency of method of isolation work using foam systems.