METHOD FOR DEVELOPMENT OF WATER-FLOODED OIL FORMATION AT LAST STAGE Russian patent published in 2012 - IPC E21B43/20 E21B47/10 

FIELD: oil and gas production.

SUBSTANCE: method for development of water-flooded oil formation at last stage includes oil extraction through production wells and water pumping through injection wells in cycling mode. Note that at the last stage of development there defined is a character of distributing current oil reserves by mapping current oil saturated thicknesses and/or this current oil saturation coefficient. The zones with different concentration of current oil reserves are determined, formation areas for treating the reserves localised in them are marked, activities on levelling the formation filtration properties in wells are carried out. At the area with residual oil those production and injection wells are determined that are located by units in line system. Injection wells are grouped by lines. Note that drainage zones of each injection well in line should not overlap the bottom-holes of the nearest production wells. First the displacement agent is pumped into odd lines of injection wells till oil output through filter-separator at least in one production well does not decrease by 20% from initial value of oil output. After that filtering direction is changed by pumping of displacement agent into even lines of injection wells till oil output through filter-separator at least in one production well does not decrease by 30% from initial value of oil output.

EFFECT: decrease of water cutting of well production and increase of water-free oil extraction volume.

1 dwg