Device for collecting and utilizing gaseous carbon dioxide for well injection and oil extraction

Abstract

The invention discloses a device for collecting and utilizing gaseous carbon dioxide for well injection and oil extraction, and belongs to the technical field of oil development, the device comprises a gas injection unit and a first booster pump, in a first oil extraction period, gas supplied by the gas injection unit is input into a gas injection wellhead at a first gas pressure value; a separation unit which is communicated with the oil outlet well opening, and the separation unit comprises a separator and a collection cavity; a reinjection unit which comprises a reinjection pipeline, a second booster pump and a control switch, and the second booster pump is used for increasing the air pressure of gas in the reinjection pipeline, so that the gas is input into the gas injection wellhead at a second air pressure value in a second oil extraction period; the second pressure value is greater than the first pressure value; and a control switch can intermittently conduct or close the reinjection pipeline, so that gas in the reinjection pipeline is intermittently input into the gas injection wellhead. By means of the intermittent gas injection mode, the gas injected later can intermittently push the gas injected previously, more carbon dioxide and crude oil are mutually dissolved, the recovery efficiency in the second oil recovery period is improved, and economic benefits are improved.

Description

technical field [0001] The application belongs to the technical field of petroleum development, and in particular relates to a well injection and production device for collecting and utilizing carbon dioxide gaseous state. Background technique [0002] In the process of oil recovery, injecting fluid downhole is an important way to enhance oil recovery. At present, the main injected fluids are steam, carbon dioxide, nitrogen and so on. Taking carbon dioxide injection as an example, carbon dioxide can achieve complete miscibility with crude oil by extracting light components in crude oil, reduce the viscosity of crude oil, expand the volume of crude oil, extract light hydrocarbons in crude oil, make them vaporize, produce miscible effect, and through molecular diffusion , reduce interfacial tension, and increase permeability through solution gas drive. Therefore, injecting carbon dioxide downhole can reduce or eliminate the capillary force of oil trapped in formation pores, ...

AI Technical Summary

Problems solved by technology

However, this method sets up a large boiler in the oil field, which makes the original limited space more tense, and also affects the normal oil production work, and the cost of carbon dioxide separation and purification is also high

[0004] In addition, as more and more carbon dioxide is injected down the well, the carbon dioxide will overflow from the production well and enter the atmosphere, which is contrary to the environmental protection concept of low-carbon production

[0005] Not only that, but in the process of oil extraction, multiple oil extraction cycles are often required to gradually flow out the crude oil in batches. As the oil extraction cycle progresses, the amount of underground oil becomes less and less, so the extraction becomes more and more difficult. Gas injection The method can significantly improve the recovery rate of crude oil in the first oil recovery cycle, but with the progress of the oil recovery cycle, the recovery rate of crude oil gradually decreases, which not only causes waste of crude oil, but also greatly increases the cost of oil recovery, economic benefits lower and lower

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