Safety connectors for oilfield operations

Abstract

The invention relates to the field of oil field downhole tubular column matching tools, in particular to a safety connector for an oil field work. The safety connector mainly aims to improve the separation function controllability. The safety connector for the oil field work comprises a first connection pipe, a second connection pipe, a first set of shear nails and an inner pipe. A first limiting structure is arranged in a first connection pipe channel. One end of the second connection pipe is provided with a second limiting structure. One end of the second connection pipe is inserted into a channel of the first connection pipe. The inner pipe is positioned on the first position in a channel of the second connection pipe. The outer surface of the pipe wall of the inner pipe makes contact with the second limiting structure in an abutted mode so that the second limiting structure can be matched with the first limiting structure in a limited mode. The superficial area of the side faces of the two ends of the axis of the inner pipe are the first area and the second area, wherein the first area value is smaller than the second area value. After the pressure in the safety connector channel is enhanced, under the action of the pressure across the side faces of the two ends of the axis of the pipe, the inner pipe moves along the axis to be separated from the second limiting structure, and the second limiting structure is capable of being movably separated from the first limiting structure.

Description

technical field [0001] The invention relates to the field of supporting tools for oilfield downhole pipe strings, in particular to a safety joint for oilfield operations. Background technique [0002] In oil and gas development operations, safety couplings for oilfield operations are special tools for downhole operations and production strings. Its function is that when an accident occurs in the downhole pipe string, the stuck pipe string can be disengaged from the safety joint used in oilfield operations, thereby creating good conditions for further handling of the accident. Safety joints for oilfield operations are generally used in construction wells with complex string structures and wells with special operation requirements. At present, there are mainly two types of safety joints commonly used in oilfield operations in vertical wells: reverse buckle type and shear nail type. The upper joint and the lower joint of the anti-buckle safety joint for oilfield operations ar...

AI Technical Summary

Problems solved by technology

The upper joint and the lower joint of the anti-buckle safety joint for oilfield operations are connected by left-handed threads. When the pipe string is stuck downhole, the pipe string needs to be rotated clockwise. If the torque transmission is not in place due to complex well conditions, it is difficult Open, the success rate is low, and the reliability is poor; while the conventional shear nail safety joint for oilfield operations includes two parts of the pipe that are plugged together, and the pipe walls of the first part and the second part are inserted through one or more shear nails Fixed, wherein, the shear nails pass through the pipe wall of the first part, and are fixed with the second part, and the first part and the second part are only connected by the shear nails.

When the strength of the shear nails is low, the safety joints for oil field operations are easily affected by the well conditions during the well operation. If the wellhead stops and the speed of lowering is too fast, the shear nails for the safety joints for oil field operations are easily broken midway, causing Separation of the first part from the second part, resulting in operational accidents

When the strength of the shear nails is too high, when the first part and the second part of the above-mentioned safety joint for oilfield operations need to be separated, because the strength of the shear nails is too high, the pulling force between the first part and the second part is difficult to separate the shear nails, The safety joints used in oilfield operations cannot realize the separation function

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