OIL DEPOSIT DEVELOPMENT METHOD Russian patent published in 2024 - IPC E21B43/16 

FIELD: oil industry.

SUBSTANCE: invention relates to oil industry and can be used in development of oil deposit of formation type in terrigenous and/or carbonate reservoirs with low-permeability reservoir and/or high viscosity of oil. Disclosed is a method of developing an oil deposit, which involves drilling production and injection wells, pumping a displacement agent through injection wells and production through production wells. Structural maps and oil-saturated thicknesses are plotted, zones with low- and/or low-permeability reservoir and/or high viscosity of oil are identified, hydrodynamic investigations are carried out, flow rate, initial formation pressure P_init and oil viscosity are measured in the selected zones. At reduction of formation pressure in production wells in these zones to 70% of initial pressure in injection wells in lower parts of structure, drilled at average depth of productive formation, in which oil production is controlled, injection of carbon dioxide gas – CO₂ is performed. CO₂ injection is continued until reaching pressure of 1.1⋅P_init. After that CO₂ injection is stopped, process exposure is performed for uniform CO₂ distribution along the front and reduction of viscosity of displaced fluid by 20-25% from the value at the beginning of development. Then, production is carried out from production wells located according to the approved grid at least by 100 m of injection wells at bottomhole pressure not lower than saturation pressure in the formation. Oil production and viscosity are measured, oil recovery factor is calculated in the first row of production wells, and at reduction of formation pressure in them to the initial one, the CO₂ injection cycle is repeated.

EFFECT: increased oil recovery from low-permeability reservoir.

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