Independent safe long-term double-pipe water injection string

Abstract

The invention discloses an independent safe long-acting double-pipe water injection pipe column. The independent safe long-acting double-pipe water injection pipe column comprises an independently arranged inner pipe and an independently arranged outer pipe. The inner pipe is arranged in the outer pipe coaxially. An inner pipe center cavity serves as an inner water injection channel communicating to a lower oil layer. An annulus formed between the inner pipe and the outer pipe serves as an outer water injection channel communicating to an upper oil layer. The annulus positions between the upper end of the inner pipe, the upper end of the outer pipe as well as the upper end outer wall of the outer pipe and a sleeve are all provided with safety control devices which are an inner pipe safety valve, an annulus safety valve and an annulus safety packer correspondingly. The inner pipe safety valve, the annulus safety valve and the annulus safety packer control the three axial channels of the inner pipe, the inner inner-outer-pipe annulus and the outer pipe and sleeve annulus correspondingly, and whole sealing during the shaft emergency condition is achieved. The lower end of the inner pipe is connected with an inner water injection pipe column body. The lower end of the outer pipe is connected with an outer water injection pipe column body. Through the independent safe long-acting double-pipe water injection pipe column, the problems of unreliable safety control, not-in-place inner and outer pipe flow separation, liable failure of an outer pipe and unbalanced pipe column stress existing in the prior art are mainly solved.

Description

Technical field [0001] The invention relates to a water injection pipe string in an oil exploitation well; in particular, it is an independent safe long-acting double-pipe water injection pipe string. Background technique [0002] At present, the water injection technology used in offshore water injection wells is mainly hollow layered water injection technology and concentric double pipe water injection technology. The former adopts the integrated technology of concentric measurement and adjustment for online measurement and adjustment of water injection wells. However, due to the restriction of well deviation, high bottom hole pressure, high temperature and other conditions, it greatly affects the success rate of measurement and adjustment, and restricts the urgent need for refined water injection at sea. Although the current concentric double-pipe water injection can be deployed on the ground, it has the characteristics of simple measurement and adjustment, accurate injection...

AI Technical Summary

Problems solved by technology

[0005] The purpose of the present invention is to provide an independent safe and long-term double-pipe water injection string, which uses annulus safety valve, inner pipe safety valve and annulus safety packer to respectively ensure the downhole safety of each channel, and uses an internal compression packer to seal In the annular space of the inner and outer pipes, the inner and outer balance packers are used as the soft anchor of the pipe string. This invention mainly solves the unreliable safety control, insufficient flow separation of the inner and outer pipes, peristalsis of the pipe string and too much force on the outer pipe in the prior art. big failure problem

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