Multifunctional carbon dioxide injection enhanced oil recovery anticorrosion structure and method

Abstract

The invention provides a multifunctional carbon dioxide injection enhanced oil recovery anticorrosion structure and method. The structure is characterized by mainly comprising a first channel, a second channel, a composite casing string, a composite tubing string and a fluid collecting area, wherein the first channel comprises an annular space, a packer and a first one-way valve, the annular spaceis formed between the composite casing string and the composite tubing string, the second channel comprises a common tubing, a sealing plug and a second one-way valve, CO2 can be separated from waterby the two channels and prevented from being mixed to form carbonic acid corroding a tube, and the fluid collecting area comprises an anti-corrosion casing, an anti-corrosion tubing, a packer, a first one-way valve, a second one-way valve, a sealing plug and a shaft bottom. The method mainly includes the processes of continuous injection of CO2 gas by passage of CO2 or water individually injectedfrom the first channel and the second channel through the fluid collecting area, slug injection of the CO2 gas or liquid, alternate injection of CO2-water and simultaneous injection of CO2-water. Thestructure and the method are applicable to the technical field of carbon dioxide gas-oil displacement development engineering.

Description

technical field [0001] The invention relates to the engineering technical field of carbon dioxide injection to enhance oil recovery, in particular to a multifunctional carbon dioxide injection to enhance oil recovery anticorrosion structure and method. Background technique [0002] In oil field development, gas flooding is a method of enhancing oil recovery developed rapidly after water flooding, polymer flooding and steam flooding. In the gas flooding production technology, because the injection of carbon dioxide into the oil layer can not only greatly increase the recovery rate, but also achieve the purpose of reducing carbon dioxide greenhouse gas emissions, making the carbon dioxide flooding technology the most widely used. Carbon dioxide is a gas with high solubility in oil and water, and has good miscibility with crude oil. Therefore, the displacement principle of this technology is to inject carbon dioxide into the oil layer, and after dissolution, the volume of crude...

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Problems solved by technology

Undoubtedly, the above method not only significantly increases the cost of oil and gas production, but also can only be applied to a single injection scheme under certain working conditions

Therefore, up to now, there is no effective injection structure and method that can adjust the injection scheme according to different working conditions and can well control carbon dioxide corrosion.

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