ENHANCED OIL RECOVERY METHOD Russian patent published in 2021 - IPC E21B33/138 

FIELD: oil industry.

SUBSTANCE: invention relates to the oil industry. The method for increasing oil recovery of reservoirs includes stopping the injection of water into the well with subsequent assembly of the injection line, which is pressurized at one and a half times the pressure from the working one, after which the injectivity of the well is determined before treatment. Further, before injecting the composition into the formation, the dependence on the reservoir properties of the formation, the injectivity of the injection well, the degree and nature of watering of the production wells of the portion of the working solutions and the components of the composition is experimentally determined. On the basis of the obtained dependence, the concentration and the optimal amount of the composition are determined. The composition is prepared in fresh water in the form of a mixture of an aqueous solution of inhibited hydrochloric acid 22-25% and commercially available sodium silicate with a density of 1.4-1.45 g/cm³ using the technology of gel-forming compositions. Sampling is carried out when the first and last part of the volume of the said mixture is pumped into the formation. Then the discharge line is again pressurized at one and a half times the pressure from the worker. Fresh water is pushed into the reservoir. The injectivity after treatment is determined and the well is closed for at least 12 hours for structure formation, followed by the opening of the well for injection.

EFFECT: increasing the isolation of highly permeable interlayers to redistribute the filtration flows of injected water by treating injection wells with carbonate rocks due to a more complete consideration of factors affecting the effectiveness of measures to increase oil recovery.

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