Safety joints and pipe strings

Abstract

The present invention provides a safety joint and a pipe string, which relates to the technical field of oil well exploitation. The safety joint comprises a first pipe body, a second pipe body and a sleeve, wherein the first pipe body and the second pipe body are threadedly connected; the sleeve is located inside a pipe body formed by connecting the first pipe body and the second pipe body, and one end of the sleeve is slidably sealed with the inner wall of the first pipe body, and the other end is slidably sealed with the inner wall of the second pipe body, and the middle part of the sleeve is connected to the second pipe body through a shearable connector; a stopper is provided on the first pipe body for preventing the sleeve from being withdrawn from the first pipe body in a direction toward the second pipe body. The pipe string comprises a safety joint. A technical effect of good use effect is achieved.

Description

Technical Field

[0001] The invention relates to the technical field of oil well exploitation, in particular to a safety joint and a pipe column. Background Art

[0002] During the well completion process, in order to facilitate the drilling after the drill is stuck or to facilitate the subsequent repair and salvage of the tubing, one or more safety joints are often connected in the tubing. However, in the prior art, various safety joints are limited by their own structures, which limits their applicable scope and may cause various problems during use. For example, the weight of the tubing connected under the safety joint is too heavy, causing the pin to be sheared, making the safety joint ineffective, resulting in poor use effect.

[0003] Therefore, providing a safety joint and a pipe column with good use effect has become an important technical problem to be solved by those skilled in the art. Summary of the invention

[0004] The object of the present invention is to provide a safety joint and a pipe column to alleviate the technical problem of poor use effect in the prior art.

[0005] In a first aspect, an embodiment of the present invention provides a safety joint, comprising a first tube body, a second tube body and a sliding sleeve, wherein the first tube body and the second tube body are threadedly connected;

[0006] The sliding sleeve is located inside a tube body formed by connecting the first tube body and the second tube body, and one end of the sliding sleeve is slidably sealed with the inner wall of the first tube body, and the other end is slidably sealed with the inner wall of the second tube body, and the middle part of the sliding sleeve is connected to the second tube body through a shearable connector;

[0007] The first tube body is provided with a limiting member for preventing the sliding sleeve from being withdrawn from the first tube body in a direction toward the second tube body.

[0008] In combination with the first aspect, an embodiment of the present invention provides a possible implementation of the first aspect, wherein the sliding sleeve includes a small diameter section and a large diameter section capable of abutting against the limiting member;

[0009] The small diameter section is used for sliding sealing with the second tube body, and the large diameter section is used for sliding sealing with the first tube body.

[0010] In combination with the first aspect, an embodiment of the present invention provides a possible implementation of the first aspect, wherein the outer wall of the large diameter section is provided with a groove that can adapt to the limiting member and transmit torque.

[0011] In combination with the first aspect, an embodiment of the present invention provides a possible implementation of the first aspect, wherein the groove is a strip groove, and the groove extends along the axial direction of the sliding sleeve.

[0012] In combination with the first aspect, an embodiment of the present invention provides a possible implementation of the first aspect, wherein an end of the groove close to the small diameter section passes through the large diameter section along the axial direction of the sliding sleeve.

[0013] In combination with the first aspect, an embodiment of the present invention provides a possible implementation of the first aspect, wherein the above-mentioned limit member adopts a positioning pin, a pin hole for installing the positioning pin is opened on the first tube body, the positioning pin protrudes out of the inner wall of the first tube body, and the positioning pin cooperates with the groove.

[0014] In combination with the first aspect, an embodiment of the present invention provides a possible implementation of the first aspect, wherein both ends of the above-mentioned sliding sleeve are provided with installation grooves, and sealing members are installed in the installation grooves, and the sliding sleeve is slidably sealed with the first tube body and the second tube body through the sealing members.

[0015] In combination with the first aspect, an embodiment of the present invention provides a possible implementation of the first aspect, wherein the outer wall of the second tube body is sleeved with a back cap for tightening the first tube body.

[0016] In combination with the first aspect, an embodiment of the present invention provides a possible implementation of the first aspect, wherein the first tube body and the second tube body are connected by a stepped thread.

[0017] In a second aspect, an embodiment of the present invention provides a pipe string, comprising the safety joint.

[0018] Beneficial effects:

[0019] An embodiment of the present invention provides a safety joint, comprising: a first tube body, a second tube body and a sliding sleeve, wherein the first tube body and the second tube body are threadedly connected; the sliding sleeve is located inside a tube body formed by connecting the first tube body and the second tube body, and one end of the sliding sleeve is slidably sealed with the inner wall of the first tube body, and the other end is slidably sealed with the inner wall of the second tube body, and the middle part of the sliding sleeve is connected to the second tube body through a shearable connecting piece; a limiting piece is provided on the first tube body for preventing the sliding sleeve from being pulled out of the first tube body in a direction toward the second tube body.

[0020] The first tube body and the second tube body are connected at one end, and the other end of the first tube body and the second tube body are connected to other pipe strings. When the safety joint needs to be disconnected in case of drill stuck or the like, a steel ball is firstly thrown into the upper pipe string, and the steel ball will fall into the sliding sleeve, and then the connecting piece between the sliding sleeve and the second tube body is cut off, thereby driving the sliding sleeve to move toward the second tube body, so that the second tube body can move freely relative to the sliding sleeve, and then the staff drives the first tube body to rotate by rotating the upper pipe string, so that the first tube body and the second tube body are separated, so that the staff can lift the first tube body out of the oil well, and the sliding sleeve will be lifted up with the first tube body; and in the process of connection and use, the threaded connection between the first tube body and the second tube body can avoid the situation that the connecting piece is cut off due to the large gravity of the lower pipe string; and the limiter arranged on the first tube body can prevent the first tube body from being separated from the second tube body after the connecting piece is cut off due to excessive gravity when the threads of the first tube body and the second tube body fail, thereby improving the use effect of the safety joint.

[0021] The present invention provides a pipe column, including a safety joint. Compared with the prior art, the pipe column has the above advantages, which will not be described in detail here. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] In order to more clearly illustrate the specific implementation methods of the present invention or the technical solutions in the prior art, the drawings required for use in the specific implementation methods or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are some implementation methods of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0023] Figure 1 A half-section schematic diagram of a safety joint provided by an embodiment of the present invention;

[0024] Figure 2 for Figure 1 A partial enlarged view of point B in the middle;

[0025] Figure 3 A schematic diagram of a sliding sleeve in a safety joint provided in an embodiment of the present invention;

[0026] Figure 4 for Figure 3 Sectional view of A-A.

[0027] icon:

[0028] 100 - the first tube body; 200 - the second tube body;

[0029] 300 - sleeve; 301 - large diameter section; 302 - small diameter section; 310 - connector; 320 - groove; 330 - mounting groove; 331 - seal;

[0030] 400 - limit piece; 500 - back cap. DETAILED DESCRIPTION

[0031] The technical solution of the present invention will be described clearly and completely below in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0032] In the description of the present invention, it is necessary to understand that the terms "length", "upper", "lower", "inner", "outer", "axial" and the like indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present invention.

[0033] In addition, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include one or more of the features. In the description of the present invention, the meaning of "plurality" is two or more, unless otherwise clearly and specifically defined.

[0034] In the present invention, unless otherwise clearly specified and limited, the terms "installed", "connected", "connected", "fixed" and the like should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0035] The present invention is further described in detail below through specific embodiments in conjunction with the accompanying drawings.

[0036] See also Figure 1 , Figure 2 and Figure 3As shown, an embodiment of the present invention provides a safety joint, including a first tube body 100, a second tube body 200 and a sleeve 300, wherein the first tube body 100 and the second tube body 200 are threadedly connected; the sleeve 300 is located inside the tube body formed by connecting the first tube body 100 and the second tube body 200, and one end of the sleeve 300 is slidably sealed with the inner wall of the first tube body 100, and the other end is slidably sealed with the inner wall of the second tube body 200, and the middle part of the sleeve 300 is connected to the second tube body 200 through a shearable connector 310; a limit member 400 is provided on the first tube body 100 for preventing the sleeve 300 from being withdrawn from the first tube body 100 in a direction toward the second tube body 200.

[0037] One end of the first tube body 100 and the second tube body 200 are connected, and the other ends of the two are connected to other pipe columns. When the safety joint needs to be disconnected due to a drill stuck, a steel ball is firstly thrown into the upper pipe column, and the steel ball will fall into the sliding sleeve 300, and then the connecting piece 310 between the sliding sleeve 300 and the second tube body 200 is cut off, thereby driving the sliding sleeve 300 to move toward the second tube body 200, so that the second tube body 200 can move freely relative to the sliding sleeve 300, and then the staff rotates the upper pipe column to drive the first tube body 100 to rotate, so that the first tube body 100 and the second tube body 200 The first tube body 100 and the second tube body 200 are separated, so that the staff can lift the first tube body 100 out of the oil well, and the sleeve 300 will be lifted out with the first tube body 100; and during the connection and use, through the threaded connection between the first tube body 100 and the second tube body, it is possible to avoid the situation where the connecting piece 310 is sheared off due to the large gravity of the lower pipe column; and the limiter 400 arranged on the first tube body 100 can prevent the first tube body 100 and the second tube body 200 from being separated after the connecting piece 310 is sheared off due to excessive gravity when the threads of the first tube body 100 and the second tube body 200 fail, thereby improving the use effect of the safety joint.

[0038] Specifically, through the threaded connection between the first tube body 100 and the second tube body 200, it is prevented that the connecting piece 310 is sheared due to excessive weight of the pipe column connected below the second tube body 200, and the first tube body 100 and the second tube body 200 are prevented from being separated. In addition, when the threaded connection between the first tube body 100 and the second tube body 200 fails, the stopper 400 provided on the first tube body 100 can prevent the sliding sleeve 300 from being separated from the first tube body 100 along with the second tube body 200, thereby preventing the first tube body 100 and the second tube body 200 from being separated.

[0039] When the safety joint needs to be separated, a steel ball is first thrown into the well, and the steel ball will fall on the sleeve 300. At this time, the sleeve 300 is sealed and connected to the steel ball. Then, pressure is applied to the well, and the connector 310 is sheared off. Then, the first tube body 100 is rotated to release the threaded connection between the first tube body 100 and the second tube body 200. Finally, the first tube body 100 and the sleeve 300 can be pulled out to complete the separation of the safety joint.

[0040] It should be noted that the middle portion of the sliding sleeve 300 refers to any position between the upper end and the lower end of the sliding sleeve 300 .

[0041] It should be noted that the connector 310 uses a shear pin, and the shear stress of the shear pin is 2800-3000 PSI.

[0042] It should also be noted that the sliding sleeve 300 is a ball seat sliding sleeve, and during the process of releasing the safety joint, the steel ball can cooperate with the ball seat sliding sleeve.

[0043] See also Figure 1 and Figure 3 As shown, in an optional solution of this embodiment, the sliding sleeve 300 includes a small diameter section 302 and a large diameter section 301 capable of abutting against the limiter 400; the small diameter section 302 is used for sliding sealing with the second tube body 200, and the large diameter section 301 is used for sliding sealing with the first tube body 100.

[0044] Specifically, the sleeve 300 has a large diameter section 301 and a small diameter section 302, the small diameter section 302 is fixedly connected to the large diameter section 301, and when the safety joint is released, the large diameter section 301 can abut against the limit piece 400 of the first pipe body 100 to prevent the large diameter section 301 from falling, so that the sleeve 300 can be lifted out of the well together with the first pipe body 100.

[0045] Furthermore, when the safety joint is used, if the threaded connection between the first tube body 100 and the second tube body 200 fails, that is, the first tube body 100 can slide up and down freely relative to the second tube body 200, the large diameter section 301 can abut against the limiter 400, thereby hanging the second tube body 200 in the first tube body 100 to prevent the second tube body 200 from separating from the first tube body 100.

[0046] At the same time, the large diameter section 301 is sealed and connected to the first pipe body 100 , and the small diameter section 302 is sealed and connected to the second pipe body 200 , so as to prevent the liquid in the wellbore from entering the sliding sleeve 300 .

[0047] A connecting piece 310 connected to the second pipe body 200 is disposed on the small diameter section 302 .

[0048] See also Figure 1 , Figure 2 , Figure 3 and Figure 4 As shown, in an optional solution of this embodiment, a groove 320 capable of matching with the limiting member 400 and transmitting torque is formed on the outer wall of the large diameter section 301 .

[0049] Specifically, the groove 320 provided on the outer wall of the large diameter section 301 can be connected to the limit piece 400. When the safety joint is used normally, while the first tube body 100 is rotated, the limit piece 400 located on the first tube body 100 will drive the sleeve 300 to rotate, thereby transmitting the torque to the second tube body 200. Such a setting can reduce the torque at the threaded connection between the first tube body 100 and the second tube body 200, thereby reducing the pre-tightening force of the threaded connection between the first tube body 100 and the second tube body 200, which is convenient for reverse buckling when the safety joint is released later.

[0050] See also Figure 1 , Figure 2 and Figure 3 As shown, in an optional solution of this embodiment, the groove 320 is a strip-shaped groove, and the groove 320 extends along the axial direction of the sliding sleeve 300 .

[0051] Specifically, when installing the limit member 400, the second tube body 200 is rotated to drive the sliding sleeve 300 to rotate, so that the groove 320 of the sliding sleeve 300 corresponds to the pin hole on the first tube body 100 where the limit member 400 is installed. The groove 320 extending along the axis of the first tube body 100 is easy to correspond to the pin hole, making it convenient for the limit member 400 to be inserted into the groove 320.

[0052] Furthermore, when the threaded connection between the first tube body 100 and the second tube body 200 fails, that is, the first tube body 100 can slide up and down relative to the second tube body 200, the sleeve 300 will slide downward relative to the limit member 400 under the action of gravity, wherein the groove 320 on the sleeve 300 extends along the axis of the first tube body 100, so that the sleeve 300 will not rotate relative to the limit member 400, and thus the second tube body 200 will not rotate, thereby reducing or even avoiding the situation where the connecting member 310 breaks due to a single twist of the sleeve 300 or the second tube body 200.

[0053] See also Figure 1 , Figure 2 and Figure 3 As shown, in an optional solution of this embodiment, one end of the groove 320 close to the small diameter section 302 passes through the large diameter section 301 along the axial direction of the sliding sleeve 300 .

[0054] By having one end of the groove 320 pass through the large diameter section 301 , the end of the groove 320 close to the small diameter section 302 will not affect the insertion of the stopper 400 , thereby shortening the length of the large diameter section 301 .

[0055] By having one end of the groove 320 pass through the large-diameter section 301 , it is convenient to process the groove 320 .

[0056] See also Figure 1 and Figure 2 As shown, in an optional solution of this embodiment, the limiting member 400 adopts a positioning pin, and a pin hole for installing the positioning pin is opened on the first tube body 100. The positioning pin protrudes from the inner wall of the first tube body 100, and the positioning pin cooperates with the groove 320.

[0057] The positioning pin is installed in the pin hole and can be inserted into the groove 320 . When the first tube body 100 rotates, the torque can be transmitted to the second tube body 200 through the positioning pin.

[0058] Specifically, the positioning pins are steel pins.

[0059] It should be pointed out that the shear stress of the steel pin is much greater than that of the shear pin.

[0060] See also Figure 1 and 3 As shown, in an optional solution of this embodiment, both ends of the sliding sleeve 300 are provided with mounting grooves 330 , and sealing members 331 are installed in the mounting grooves 330 . The sliding sleeve 300 is slidably sealed with the first tube body 100 and the second tube body 200 through the sealing members 331 .

[0061] Specifically, an installation groove 330 is formed on the outer wall of the sliding sleeve 300 , and the sealing member 331 is installed in the sealing groove, so that the installation and positioning of the sealing member 331 are convenient.

[0062] See also Figure 1 As shown, in an optional solution of this embodiment, the outer wall of the second tube body 200 is provided with a back cap 500 for tightening the first tube body 100 .

[0063] Specifically, the back cap 500 is threadedly connected to the second tube body 200 , and the back cap 500 applies a pre-tightening force to the first tube body 100 , so that the second tube body 200 is firmly connected to the first tube body 100 without the phenomenon of undercut.

[0064] When installing the back cap 500 , first tighten the second tube 200 and the first tube 100 , and then tighten the back cap 500 , so that the connection stability between the first tube 100 and the second tube 200 can be enhanced by the back cap 500 .

[0065] In an optional solution of this embodiment, the first tube body 100 and the second tube body 200 are connected by a stepped thread.

[0066] It should be noted that the inner wall of the first tube body 100 is provided with a partial trapezoidal thread, and the outer wall of the second tube body 200 may be provided with a partial trapezoidal thread. The partial trapezoidal thread can reduce or even eliminate the problem of the first tube body 100 and the second tube body 200 being difficult to buckle.

[0067] The embodiment of the present invention provides a pipe string including a safety joint. Compared with the prior art, the pipe string has the above advantages, which will not be described in detail here.

[0068] The tubing string includes other production tools, and the production tools can be connected together through safety joints.

[0069] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or replace some or all of the technical features therein by equivalents. However, these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A safety joint, characterized in that: include: A first tube body (100), a second tube body (200) and a sliding sleeve (300), wherein the first tube body (100) and the second tube body (200) are threadedly connected; The sliding sleeve (300) is located inside a tube body formed by connecting the first tube body (100) and the second tube body (200), and one end of the sliding sleeve (300) is slidably sealed with the inner wall of the first tube body (100), and the other end is slidably sealed with the inner wall of the second tube body (200), and the middle part of the sliding sleeve (300) is connected to the second tube body (200) via a shearable connector (310); The first tube body (100) is provided with a stopper (400) for preventing the sliding sleeve (300) from being withdrawn from the first tube body (100) in a direction toward the second tube body (200); The sliding sleeve (300) comprises a small diameter section (302) and a large diameter section (301) capable of abutting against the stopper (400); the small diameter section (302) is used for sliding sealing with the second tube body (200), and the large diameter section (301) is used for sliding sealing with the first tube body (100); The outer wall of the large diameter section (301) is provided with a groove (320) capable of matching with the limiting member (400) and transmitting torque; The outer wall of the second tube body (200) is provided with a back cap (500) for tightening the first tube body (100); The groove (320) is a strip-shaped groove, and the groove (320) extends along the axial direction of the sliding sleeve (300); The position limiting member (400) adopts a positioning pin, and the first tube body (100) is provided with a pin hole for installing the positioning pin. The positioning pin protrudes from the inner wall of the first tube body (100), and the positioning pin cooperates with the groove (320).

2. The safety joint according to claim 1, characterized in that: One end of the groove (320) close to the small diameter section (302) penetrates the large diameter section (301) along the axial direction of the sliding sleeve (300).

3. The safety joint according to claim 1 or 2, characterized in that: Both ends of the sliding sleeve (300) are provided with mounting grooves (330), and sealing members (331) are installed in the mounting grooves (330). The sliding sleeve (300) is slidably sealed with the first tube body (100) and the second tube body (200) via the sealing members (331).

4. The safety joint according to claim 1 or 2, characterized in that: The first tube body (100) and the second tube body (200) are connected via a stepped thread.

5. A pipe column, characterized in that: The invention comprises the safety joint as described in any one of claims 1 to 4.

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