METHOD FOR DEVELOPMENT OF LOW-PERMEABILITY HEADERS Russian patent published in 2020 - IPC E21B43/20 E21B49/00 

FIELD: oil and gas industry.

SUBSTANCE: invention relates to development of oil deposits and increases efficiency of oil production from productive deposits with hard-to-recover oil reserves. Proposed method comprises extraction of oil through production wells. First, a core is sampled at the deposit section and analyzed. According to core analysis data, open porosity, effective permeability of oil-saturated header, depth samples of oil are taken and content of dissolved gas, saturation pressure and oil viscosity are determined. Development of reservoir is carried out, potential yield of formation fluid and water content of extracted product are determined. Data obtained is isolated low-permeability reservoirs with an open porosity of from 5 to 12%, the effective permeability from 0.001 to 0.01 mcm², the parameters of reservoir oil - gas content of at least 10 m³/t, saturation pressure of not less than 2 MPa, oil viscosity of not more than 30 MPa*s, water content of not more than 30%. Wells grid is designed. At design stage absolute elevation of formation roof is determined. Deposit area is divided into four zones relative to deposit arch and project wells are distributed by zones. Performance of annular gas-extracting device is calculated for each well by mathematical formula. Thereafter, production wells are drilled, and geophysical investigations are carried out to isolate the collector. Obtained elevation absolute elevation data are obtained. Then absolute marks of formation roofing are compared between adjacent wells, if they mismatch relative to designed ones, zones location is corrected with redistribution of design wells by zones and correction of Czone correction coefficient, accurate calculation of annular gas extraction device productivity is carried out. Depth-pumping equipment is lowered and wells are put into operation.

EFFECT: method increases efficiency of developing low-permeability reservoirs, enables to maintain high rates of selection of low-permeability reservoirs due to an integrated approach, including combination of gas lift mode of gas dissolved in oil and formation reservoir energy.

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