METHOD FOR OIL RESERVOIR DEVELOPMENT AT LATER STAGE BY WATER-GAS HYDRODYNAMIC ACTION DURING PERIODICAL GASEOUS PHASE DISPERSION CHANGE Russian patent published in 2008 - IPC E21B43/22 

FIELD: oil production, particularly enhanced recovery methods for obtaining hydrocarbons.

SUBSTANCE: method involves determining oil-saturated thickness distribution pattern; periodically operating highly-flooded well located in zones with decreased oil-saturated thickness; operating wells with increased oil-saturated thickness at accelerated fluid production regimes; injecting water-gas dispersed mixture through injection wells, wherein the water-gas dispersed mixture includes reservoir water and purified oil gas dispersed in water; periodically changing water-gas dispersed mixture dispersion. First of all water-gas dispersed mixture having bubble dimensions comparable with pore channel dimensions flushed with water is injected up to 2-6.1% reduction of water content in produced fluid. Then water-gas dispersed mixture with gas bubbles comparable with capillary and sub-capillary oil-containing pore channels is injected to provide 0.5-2.5% increase of water content in produced fluid. Said water-gas dispersed mixture dispersion alternation is maintained during total injection period.

EFFECT: increased oil recovery due to extended reservoir coverage with treatment and improved displacement efficiency.

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