METHOD FOR RECOVERY OF RESIDUAL OIL RESERVES Russian patent published in 2014 - IPC E21B43/20 

FIELD: oil and gas industry.

SUBSTANCE: invention pertains to oil producing industry and can be used at final stage of oil deposit developments with use of contour waterflooding. The concept of the invention is as follows: method includes contour waterflooding of oil deposit with use of injection and production wells. The most successful well is selected among production wells. Oil recovery coefficient and water cut by weight is checked for this well. When water cut by weight reaches its limit value and oil production is stopped hydrocarbon gas is pumped in preset volume to the above well. By hydrocarbon gas water is displaced from annular space of the most successful well and drainage area of oil strata and by water pumped to neighbouring injection wells impact is made on neighbouring injection wells. At that after hydrocarbon gas pumping the most successful production well is switched to production of oil-gas mixture. When water cut by weight reaches its limit value in other production wells hydrocarbon gas is pumped to them also.

EFFECT: increasing recovery efficiency of remaining reserves.