A hydraulically activated reverse buckle and throw away mechanism

Abstract

The invention discloses a hydraulically started back-off releasing mechanism. A feeding sub is connected with a releasing sub; an annulus is formed between the releasing sub and the feeding sub; a sealing sleeve is arranged between the releasing sub and the feeding sub; a piston is arranged in the annulus cavity and is in splined joint with the releasing sub; the feeding sub is in splined joint with the piston; the piston is positioned by a shear pin and is fixedly arranged on the releasing sub; a first through hole communicated with an inner hole of the feeding sub and the annulus cavity of the upper part of the piston respectively is formed in the feeding sub; a second through hole communicated with the annulus cavity of the lower part of the piston and the annulus of a sleeve respectively is formed in the releasing sub. According to the hydraulically started back-off releasing mechanism, the defect that a pipe string cannot be rotated forwardly in the ground during tool descending and before completion of operation existing in the conventional left-hand thread back-off releasing mechanism can be overcome, and the problems of accidental shearing of the shear pin and advanced releasing of the tool existing in the conventional mechanical and hydraulic double-action releasing tool are also solved; the hydraulically started back-off releasing mechanism has higher reliability and a wider application range.

Description

technical field [0001] The invention relates to a hand-losing mechanism, in particular to a hydraulically activated back-and-forth hand-losing mechanism, which belongs to downhole tools. Background technique [0002] During drilling and downhole operations, some operating tools are sent to the working position through the feeding pipe string, and remain in the well after the operation is completed, and the feeding pipe string is lifted out of the ground through the release mechanism and the downhole tool. [0003] At present, the left-hand thread undercut mechanism is commonly used to realize tool throwing away. This mechanism is easy to operate and has been widely used in engineering practice. For example, what Chinese patent "CN201120415989.4" discloses is a kind of downhole pipe string dual-action hands-off device used in the petroleum industry. The disclosure date is July 11, 2012. There is a pressure relief hole, and the inner cavity is equipped with a ball seat, and t...

AI Technical Summary

Problems solved by technology

[0006] The purpose of the present invention is to overcome the defect that the conventional left-handed thread undercutting and throwing mechanism cannot rotate the pipe string forward when the tool enters the well and before the operation is completed, and overcome the accidental shearing of the shear nails in the existing mechanical and hydraulic double-action throwing tools In order to solve the problem of losing hands in advance, a hydraulically activated back-off mechanism is provided. During the process of entering the well and before the completion of the operation, the pipe string can be rotated forward on the ground. The set shear nails are cut by the set pressure. The running resistance is borne by the left-handed thread, the shear pin is not stressed, and the tool will not be lost in advance; under abnormal circumstances, if the cycle pressure is high, the shear pin will be cut in advance, and the tool is still connected by the left-handed thread, and the tool will not be lost in advance , the function is more reliable and the security is higher

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