Devices used in the carbon dioxide huff and puff recovery method for low permeability reservoirs

Abstract

The application discloses a device used in a carbon dioxide huff and puff oil recovery method for low-permeability reservoirs, and belongs to the technical field of carbon dioxide huff and puff oil recovery. The device includes: a carbon dioxide injection mechanism and a wellhead switch mechanism. The carbon dioxide injection mechanism includes an injection casing and a plunger. A first injection chamber and a second injection chamber are formed between the plunger and the casing, and a first channel is arranged inside the plunger. and the second channel, the injection housing is provided with a drive valve connected to the hydraulic pump, the plunger moves so that the first channel or the second channel communicates with the drive valve; the wellhead switch mechanism includes a switch housing and a three-way pipe, A switch spool is arranged in the switch housing. When the first injection chamber or the second injection chamber injects a certain amount of carbon dioxide into the well head, it can prompt the switch valve core to move automatically to realize the well shut-in, and when the pressure in the well reaches a predetermined value, the well will be automatically opened for production. Using this device can Automated oil recovery to improve oil recovery efficiency.

Description

technical field [0001] The application relates to a device used in a carbon dioxide huff and puff oil recovery method for low-permeability reservoirs, and belongs to the technical field of carbon dioxide huff and puff oil recovery. Background technique [0002] One of the characteristics of my country's petroleum resources is that low-permeability reservoirs are widely distributed. During the exploitation of low-permeability reservoirs, a certain amount of carbon dioxide is injected into the oil layer under a certain pressure, and then the well is shut down, so that the injected carbon dioxide flows along the oil layer. When cracks are mixed with crude oil, carbon dioxide can dissolve in crude oil, reduce the viscosity of crude oil, improve the fluidity of crude oil, and expand the volume of crude oil, thereby enhancing the recovery of crude oil. [0003] However, the existing carbon dioxide injection device only injects the carbon dioxide in the carbon dioxide storage tank i...

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Problems solved by technology

[0003] However, the existing carbon dioxide injection device only injects the carbon dioxide in the carbon dioxide storage tank into the wellhead through the pipeline, and manually detects the injection amount of carbon dioxide to shut down the well, and also needs to manually open the well to produce oil, which consumes a lot of manpower Material resources, unable to realize automatic oil recovery, high operating cost, low oil recovery efficiency

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