METHOD OF INCREASE OF RESERVOIR RECOVERY BY INJECTION OF WATER-GAS MIXTURE Russian patent published in 2015 - IPC E21B43/18 

FIELD: oil and gas industry.

SUBSTANCE: invention relates to oil and gas production industry and, in particular, to field development by means of water and gas injection into injection wells and withdrawal of oil through production wells. The method includes the preparation of the water-gas mixture within the range of gas content values, ensuring the operational stability of the pumping unit, injection of the mixture into one or more wells using the unit with a centrifugal pump and displacement of oil from the formation with the tank pressure maintaining system. Meanwhile before injection of the water-gas mixture into the formation, the correlation of oil displacement coefficient with the gas content in the water-gas mixture at formation conditions is determined. On the basis of the obtained correlation the optimum value of the gas content is selected. In the well itself the correlation between the injection capacity and the gas content is determined. The working relation of water and gas discharge values upstream the mixer is identified. Further, with the advancing of displacement front located between injection and production wells, the current value of the gas content at the displacement front is calculated with the pressure correlation. After that the gas content in the water-gas mixture is decreased, maintaining it at the optimum level.

EFFECT: simplification of technology with simultaneous decrease of expenses for its implementation due to more thorough consideration of the factors influencing the efficiency of oil recovery increase measures.

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