Hydraulic micro-rotation safety joint for downhole tubular column

Abstract

The invention relates to a hydraulic micro-rotation safety joint for a downhole tubular column. The hydraulic micro-rotation safety joint comprises an upper joint and a lower joint, wherein central holes of the two joints share the same axis and are communicated mutually. A cylinder extending upwardly is arranged at the upper end of the lower joint. A sliding sleeve that can slide axially along the inner wall of the cylinder is installed in the inner cavity of the cylinder, wherein the central hole of the sliding sleeve is reduced gradually from top to bottom; a ball base in a horn shape is arranged at the lower end of the sliding sleeve; the ball base is provided with a matched steel ball for turning off the ball base; and the mouth of the lower end of the ball base is communicated with the central hole formed in the lower joint. The outer wall of the lower end of the sliding sleeve is fixed on the cylinder by a shearing pin. The e lower part of the upper joint is inserted into the cylinder and is embedded with the inner wall of the cylinder after rotation; and the lower end of the upper joint is plugged with the upper end of the sliding sleeve by a spline. An upper joint outer step is arranged at the middle part of the upper joint and is pressed on the upper port of the cylinder, wherein the diameter of the part under the upper joint outer step is reduced gradually. The innercavity of the cylinder is reduced gradually from top to bottom. The safety joint is operated conveniently and is protected from being affected by the friction of the tubular column and the well deviation; and the disconnection success rate is high.

Description

technical field [0001] The invention relates to a safety joint, in particular to a hydraulic micro-rotation safety joint for downhole pipe strings, and belongs to the technical field of screw drilling tools. Background technique [0002] The safety joint is an auxiliary tool used in downhole operations and production strings. When a stuck pipe accident occurs, the stuck pipe string can be disengaged from the safety joint, thereby creating good conditions for further handling of the accident. At present, there are mainly two types of safety joints commonly used in oil fields: sawtooth type and square buckle type. These two safety joints are composed of upper joints, lower joints and sealing rings. The upper end of the upper joint has an internal thread connected with the pipe string, and the lower half has a wide serrated external thread. There is a "figure eight" convex-concave structure on the outer cylindrical surface between these two parts. The lower end of the lower ...

AI Technical Summary

Problems solved by technology

It is precisely because of the threaded connection, and the applied torque is opposite to the thread direction of the pipe string, affected by the friction resistance between the pipe string and the casing wall and the well deviation, the transmission of the torque and the weight of the pipe string is very difficult, and the phenomenon of being unable to retreat often occurs

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