METHOD OF DEVELOPMENT OF WATER-ENCROACHED OIL POOL WITH NONUNIFORM GEOLOGICAL STRUCTURE Russian patent published in 2002 - IPC

FIELD: oil and gas producing industry; methods of increase of oil recovery from formations and reduction of producing well water-encroachment. SUBSTANCE: method includes injection into formation through injection well of aqueous solution of alkali metal silicate and oil withdrawal through producing wells. Additionally injected together are aqueous solutions of ammonium sulfate and calcium chloride whose reaction results in precipitation of calcium sulfate and ammonium chloride in dissolved state. Then, injected into formation is aqueous solution of alkali metal silicate which forms, together with ammonium chloride, bulky sediment of silicon oxide. Injected additionally into formation is gel-forming solution based on aqueous solution of alkali metal silicate and ammonium sulfate. EFFECT: increased oil recovery from formation, reduced water cutting of produced oil due to additional isolation of nonuniform and high-permeability formations with reduced consumption of reagents. 2 cl, 1 tbl