A safety shear joint for connecting drilling tools and an operation method thereof

Abstract

The present invention discloses a safety shear joint for connecting a drill tool and an operating method thereof, wherein the joint comprises an outer sleeve, an inner sleeve, a shear ball seat, a shear pin, a positioning ball and a shear ball; the present invention solves the problem that the drill tool cannot be released at a designated position after being stuck, by installing the safety shear joint at a designated position in advance, if the pipe string encounters resistance, the pipe string can be separated up and down at the ball seat position by dropping a ball into the pipe string and applying pressure inside the drill tool, thereby creating convenience for subsequent salvage operations.

Description

Technical Field

[0001] The invention belongs to the technical field of drilling engineering, and in particular relates to a safety shear joint for connecting a drilling tool and an operating method thereof. Background Art

[0002] If a conventional drill string encounters obstruction during entry into the well, the only way to free the string is by moving the drill string up and down, rotating it forward and backward, and circulating it forward and backward. This process is subject to great uncertainty. If the operation fails, the drill string usually has to be reversed to free the string above the stuck point. The unpredictable release point makes subsequent salvage operations difficult. Summary of the Invention

[0003] The purpose of the present invention is to overcome the deficiencies of the prior art and provide a safety shear joint for connecting a drilling tool and an operating method thereof.

[0004] The present invention is achieved through the following technical solutions:

[0005] A safety shear joint for connecting a drilling tool, comprising an outer sleeve, an inner sleeve, a shear ball seat, a shear pin, a positioning ball and a shear ball;

[0006] A stepped groove for limiting the position of the liner sleeve coupling is formed on the upper portion of the outer sleeve, a positioning ball groove is formed on the inner wall of the outer sleeve, and an external circulation hole is formed on the wall of the outer sleeve;

[0007] The inner sleeve is arranged inside the outer sleeve, an inner sleeve collar is formed on the upper part of the inner sleeve, a positioning ball hole corresponding to the positioning ball groove is formed on the wall of the inner sleeve, and an inner circulation hole corresponding to the outer circulation hole is formed on the wall of the inner sleeve;

[0008] The shear ball seat is arranged inside the inner sleeve and covers the positioning ball hole. The upper part of the shear ball seat is connected to the inner sleeve through a shear pin. The positioning ball is installed in the positioning ball hole and the positioning ball groove. The outer sleeve and the inner sleeve are limited by squeezing the positioning ball by the shear ball seat. The shear ball is arranged above the shear ball seat in the inner sleeve coupling.

[0009] In the above technical solution, sealing rings are provided on the inner wall of the inner sleeve on both sides of the positioning ball hole.

[0010] In the above technical solution, the number of the positioning balls, positioning ball holes and positioning ball grooves is 4, and they are arranged at 90 degrees apart from each other.

[0011] In the above technical solution, the number of the shear pins is 4, and they are arranged at 90 degrees apart from each other.

[0012] A method for operating a safety shear joint connecting a drilling tool is as follows:

[0013] The safety shear joint is connected to the lowest end of the drill string. When the pipe string encounters resistance, a shear ball is put into the drill string, and the shear ball falls onto the shear ball seat. The drill string is pressurized to shear the shear pin, and the shear ball seat loses its support and moves to the lowest end of the inner sleeve. The shear ball and the positioning ball both fall onto the top of the ball seat, and the drill string is lifted up. The inner sleeve is pulled out with the drill string, and the circulation hole can establish internal and external circulation.

[0014] Compared with the prior art, the advantages of the present invention are:

[0015] The present invention provides a safety shear joint for connecting drill tools and a construction process to solve the problem that the drill tool cannot be released at the designated position after it is stuck. By installing the safety shear joint at the designated position in advance, if the pipe string encounters obstruction, a ball can be dropped into the pipe string and pressure can be applied inside the drill tool to separate the pipe string up and down at the ball seat position, creating convenience for subsequent salvage operations. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 : Schematic diagram of the overall structure of the present invention.

[0017] Figure 2 : The state when connected to the drilling tool and entering the well.

[0018] Figure 3 : Throw the shear ball and prepare to press the shear ball seat to perform the release operation.

[0019] Figure 4 : The shear ball seat falls to the bottom of the inner sleeve, and the shear pin and positioning ball fall into the bottom shear ball seat position.

[0020] Figure 5 : The inner sleeve is pulled out along with the drilling tool.

[0021] Figure 6 : The state of the jacket remaining underground.

[0022] Among them: 1 is the shear ball, 2 is the shear pin, 3 is the positioning ball, 4 is the sealing ring, 5 is the shear ball seat, 6 is the circulation channel, 7 is the inner sleeve, 7-1 is the inner sleeve coupling, 7-2 is the positioning ball hole, 7-3 is the inner circulation hole, 8 is the outer sleeve, 8-1 is the stepped groove, 8-2 is the positioning ball groove, and 8-3 is the outer circulation hole.

[0023] For ordinary technicians in this field, other relevant drawings can be obtained based on the above drawings without any creative work. DETAILED DESCRIPTION

[0024] The technical solution of the present invention is further described below with reference to specific embodiments.

[0025] Example

[0026] like Figure 1As shown: A safety shear joint for connecting drilling tools, comprising an outer sleeve 8, an inner sleeve 7, a shear ball seat 5, a shear pin 2, a positioning ball 3 and a shear ball 1;

[0027] The upper portion of the outer sleeve 8 is formed with a stepped groove 8-1 for limiting the coupling of the inner sleeve 7, the inner wall of the outer sleeve is formed with a positioning ball groove 8-2, and the outer sleeve wall is formed with an outer circulation hole 8-3;

[0028] The inner sleeve 7 is arranged inside the outer sleeve 8, and an inner sleeve coupling 7-1 is formed on the upper part of the inner sleeve 7. A positioning ball hole 7-2 corresponding to the positioning ball groove 8-2 is formed on the wall of the inner sleeve 7, and an inner circulation hole 7-3 corresponding to the outer circulation hole 8-3 is formed on the wall of the inner sleeve.

[0029] The shear ball seat 5 is arranged inside the inner sleeve 7 and covers the positioning ball hole 7-2. The upper part of the shear ball seat 5 is connected to the inner sleeve 7 through the shear pin 2. The positioning ball 3 is installed in the positioning ball hole 7-2 and the positioning ball groove 8-2. The outer sleeve 8 and the inner sleeve 7 are limited by squeezing the positioning ball 3 by the shear ball seat 5; the shear ball 1 is arranged above the shear ball seat 5 in the inner sleeve coupling 7-1.

[0030] In this embodiment, sealing rings 4 are provided on the inner wall of the inner sleeve 7 on both sides of the positioning ball hole 7 - 2 .

[0031] In this embodiment, the number of the positioning balls 3, positioning ball holes 7-2 and positioning ball grooves 8-2 is four, and they are arranged at 90 degrees apart from each other.

[0032] In this embodiment, the number of the shear pins 2 is 4, and they are arranged at 90 degrees apart from each other.

[0033] The safety shear joint is connected to the lower end of the drilling tool, such as Figure 2 Shown: The safety shear joint is connected to the drilling tool when entering the well.

[0034] When the string encounters resistance, the shear ball is put into the drill string and falls onto the shear ball seat. Figure 3 Shown: Throw the shear ball to prepare to press the shear ball seat to perform the release operation.

[0035] The drill bit is pressed to achieve shear pin shearing, the shear ball seat loses support and moves to the bottom of the inner sleeve, and the shear ball and fixed ball both fall above the ball seat. Figure 4 As shown: the shear ball seat falls to the bottom of the inner sleeve, and the shear pin and positioning ball fall into the bottom shear ball seat position.

[0036] Lift the drill bit and the inner sleeve will be pulled out along with the drill bit. Figure 5 Shown: The inner sleeve is pulled out along with the drilling tool.

[0037] The circulation channel can establish internal and external circulation, such as Figure 6 Shown: The jacket remains underground.

[0038] The above is an exemplary description of the present invention. It should be noted that, without departing from the core of the present invention, any simple deformation, modification or other equivalent replacement that can be made by other skilled in the art without expending creative labor falls within the scope of protection of the present invention.

Claims

1. A safety shear joint for connecting a drilling tool, characterized by: Includes outer sleeve, inner sleeve, shear ball seat, shear pin, positioning ball and shear ball; A stepped groove for limiting the position of the liner sleeve coupling is formed on the upper portion of the outer sleeve, a positioning ball groove is formed on the inner wall of the outer sleeve, and an external circulation hole is formed on the wall of the outer sleeve; The inner sleeve is arranged inside the outer sleeve, an inner sleeve collar is formed on the upper part of the inner sleeve, a positioning ball hole corresponding to the positioning ball groove is formed on the wall of the inner sleeve, and an inner circulation hole corresponding to the outer circulation hole is formed on the wall of the inner sleeve; The shear ball seat is arranged inside the inner sleeve and covers the positioning ball hole. The upper part of the shear ball seat is connected to the inner sleeve through a shear pin. The positioning ball is installed in the positioning ball hole and the positioning ball groove. The outer sleeve and the inner sleeve are limited by squeezing the positioning ball by the shear ball seat. The shear ball is arranged above the shear ball seat in the inner sleeve coupling. Sealing rings are provided on the inner wall of the inner sleeve on both sides of the positioning ball hole; the number of the positioning balls, positioning ball holes and positioning ball grooves is 4, which are arranged at 90 degrees apart from each other; the number of the shear pins is 4, which are arranged at 90 degrees apart from each other.

2. A method for operating a safety shear joint for connecting a drilling tool according to claim 1, characterized in that: The safety shear joint is connected to the lowest end of the drill string. When the pipe string encounters resistance, a shear ball is put into the drill string, and the shear ball falls onto the shear ball seat. The drill string is pressurized to shear the shear pin, and the shear ball seat loses its support and moves to the lowest end of the inner sleeve. The shear ball and the positioning ball both fall onto the top of the ball seat, and the drill string is lifted up. The inner sleeve is pulled out with the drill string, and the circulation hole can establish internal and external circulation.

Images