DEVELOPMENT METHOD OF NON-HOMOGENEOUS OIL DEPOSIT Russian patent published in 2013 - IPC E21B43/20 

FIELD: oil and gas industry.

SUBSTANCE: method involves cyclic pumping of displacement agent through system of injection wells and extraction of oil through the system of production wells; variation of flooding pattern that is chosen based on properties of oil deposit. According to the invention, first, zones of independent development are determined, in which the intensity of flooding pattern is chosen as per water cut interval of oil in that zone as per cellular, thirteen-point or multi-row flooding pattern. At that, injection wells are located in lowered part of oil-saturated structure. Then, flooding is performed on the side of injection wells with duration of half-cycle periods of 1-6 months until water-cut is 10-20%. After that, production wells are separated into two groups. Wells located in the zone with water-cut above average value refer to the first group, and wells located in the zone with water-cut below average value refer to the second group. Bottomhole pressure in the first group is set to the pressure of vertical cracks opening, and in the second group - by 20-25% more than in the first group. Action is performed as per modular, ten-point, nine-point or three-row flooding pattern in groups of wells with series actions of 3-5 cycles with variation of pumping and down time from action to action until water-cut of 85-90% is achieved. Then, complex of methods intended to increase oil recovery of deposit formations is implemented, and single-row flooding pattern and cyclic extraction of oil from production wells is chosen.

EFFECT: increasing current withdrawals of oil and final oil recovery factor at simultaneous reduction of recovered and pumped water from the deposit owing to increasing the flooding and displacement coverage of low-permeable layers, zones and modules.

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