FORMATION PRESSURE MAINTENANCE METHOD USING GAS COMPOSITIONS Russian patent published in 2022 - IPC E21B43/16 

FIELD: oil and gas industry.

SUBSTANCE: invention relates to the oil and gas industry and can be used in the recovery of associated gas and associated formation water generated during the development and operation of oil or gas condensate fields. The method includes injection into the formation of a water-gas mixture containing water, associated produced water and associated produced gas composition, including methane-propane-ethane-butane mixture. At the same time, flows are controlled with the possibility of changing the composition of the components of the gas composition. Associated produced water and gas are taken after a multi-stage process of gas-water-salt separation, after each of the stages, the content of the ingredients of associated produced water and gas in water and gas is analyzed to determine the range of the percentage mole composition of ingredients in the methane-propane-ethane-butane mixture, which exclude formation of salts and hydrates in reservoir conditions. The analysis of the formation cores determines the optimal injection pressure interval, which ensures the most efficient injection of the water-gas mixture without compromising the integrity of the formation. When injecting a water-gas mixture, the composition of the components of the gas composition is changed so that the percentage of the molar composition of each of the ingredients or one of the most influencing ingredients in the methane-propane-butane mixture and the injection pressure are in the range determined under laboratory conditions.

EFFECT: pressure interval is maintained, which excludes violation of the integrity of the formation, the formation of insoluble salts and hydrates in the formation, which clog the formation, is excluded.

1 cl, 3 tbl