METHOD TO DEVELOP OIL DEPOSIT Russian patent published in 2003 - IPC

FIELD: oil production. SUBSTANCE: in accordance with method oil is withdrawn through production wells till formation pressure goes down beneath saturation pressure, to value at which 8-25% of porous volume of pool is filled with gas liberated from oil. Prior to flooding water fringe containing foam-forming oil-soluble reagent with concentration of 0.01-5.0% by mass is pumped through injection wells in volume of 2-10% of porous volume of pool. This reagent solves in oil better than in water. Subsequent development of deposit is carried out under mode of keeping present formation pressure by mechanism of injection of water. EFFECT: increased oil output of deposit.