Torque transmission back-off safety joint

Abstract

The utility model relates to the technical field of devices for disassembling or taking out tools, in particular to a torque transmission back-off safety connector. A torque transmission back-off safety connector comprises an upper connector, a center pipe and an outer barrel, the upper connector is located between the center pipe and the outer barrel, the center pipe is connected with the upper connector through a shear pin, the outer barrel is in reverse threaded connection with the upper connector, a rotation stopping key groove structure is arranged on the center pipe, and the upper connector and the outer barrel are correspondingly provided with matched key groove structures. Torsion transmission is achieved between the upper connector and the outer cylinder through the rotation-stopping key groove structure of the center pipe, when a ball is thrown to the ball seat of the center pipe for pressing, the shear pin is sheared off so that the rotation-stopping key groove structure of the center pipe can be separated from the matched key groove structure, and rotation-stopping matching between the upper connector and the outer cylinder can be relieved. Torsion transmission is achieved between the upper connector and the outer barrel through a rotation stopping key groove structure of the center pipe, the structural strength is high, and the locking matching mode is more reliable.

Description

Technical Field

[0001] This utility model relates to the technical field of devices for disassembling or removing tools, and in particular to a twist-and-loop safety connector. Background Technology

[0002] A safety joint is a tool used in oil and gas well drilling, completion, and testing tubing strings to separate the upper and lower tubing strings via surface operations. Safety joints are often used in conjunction with downhole retrieval tubing strings. The safety joint is lowered into the well along with other tools; if the lower tubing string gets stuck, the safety joint is used to release the stuck lower tubing string and retrieve the upper tubing string. Safety joints are widely used in drilling, completion, testing, production, and reservoir stimulation.

[0003] An existing utility model patent, such as the one disclosed in authorization announcement number CN2866798Y, discloses a safe release connector, which includes a separating claw sleeve connector. The separating claw sleeve connector is connected to the main body via a reverse snap. A retrieval section is connected to the lower port of the main body. A locking groove is provided on the inner surface of the main body. A petal-shaped limiting claw is provided at the lower part of the separating claw sleeve connector. A sliding sleeve is connected to the separating claw sleeve connector through a shear pin. A boss is provided on the inner surface of the separating claw sleeve connector below the shear pin. A gap is provided on both sides of the boss between the sliding sleeve and the separating claw sleeve connector. A locking sleeve is connected to the lower part of the sliding sleeve. The limiting claw is embedded in the locking groove through the locking sleeve. It can transmit torque in different directions and can safely release the hand.

[0004] However, the aforementioned utility model patent achieves the limiting and locking between the main body and the separating claw sleeve joint by locking the petal-shaped limiting claw with the locking groove through the locking sleeve. Because the limiting claw is petal-shaped and located at the end of the separating claw sleeve, and because the underground temperature is high and the torque to be transmitted is large in some cases, the limiting claw is prone to breakage during the screwing process, resulting in limiting failure, affecting use, and having low structural strength. Utility Model Content

[0005] The purpose of this utility model is to provide a torsion-transferring safety connector to solve the problem that existing safety release connectors, which use a petal-shaped limiting claw and locking groove for limiting, are prone to breakage of the limiting claw during the twisting process, resulting in limiting failure, affecting use, and having low structural strength.

[0006] The present invention provides a torque-transmitting reverse-clamp safety connector with the following technical solution: A torque-transmitting reverse-clamp safety connector includes an upper connector, a central tube, and an outer cylinder. The upper connector is located between the central tube and the outer cylinder. The central tube and the upper connector are connected by a shear pin. The outer cylinder and the upper connector are connected by a reverse thread. The central tube is provided with an anti-rotation keyway structure. The upper connector and the outer cylinder are provided with corresponding mating keyway structures. Torque transmission between the upper connector and the outer cylinder is achieved through the anti-rotation keyway structure of the central tube. When a ball is thrown and pressed onto the ball seat of the central tube, the shear pin is sheared off, causing the anti-rotation keyway structure of the central tube to disengage from the mating keyway structure, thereby releasing the anti-rotation fit between the upper connector and the outer cylinder.

[0007] Furthermore, the anti-rotation keyway structure is an anti-rotation key, and the keyway structure is a anti-rotation keyway.

[0008] Furthermore, a limiting boss is provided on the inner wall of the upper connector, and an anti-detachment outer edge is provided at the upper end of the central tube to cooperate with the limiting boss, so as to prevent the central tube from detaching from the upper connector during the downward movement.

[0009] Furthermore, the outer cylinder includes an inverted outer tube and a lower connector, the inverted outer tube being connected to the upper connector via a reverse thread, and the inverted outer tube being connected to the lower connector via a forward thread.

[0010] Furthermore, the shear pin is also radially inserted into the outer cylinder.

[0011] Furthermore, a ball seat is detachably connected to the central tube, and an anti-detachment outer edge is provided on the ball seat.

[0012] Furthermore, the anti-rotation key is integrally formed with the central tube.

[0013] Furthermore, the anti-rotation key is a spline.

[0014] Furthermore, the shear pin corresponds to a spline setting.

[0015] Furthermore, a clearance gap is provided between the central tube and the outer cylinder below the anti-rotation key to allow the anti-rotation key to slide in, and a through hole is provided on the outer cylinder to communicate with the clearance gap.

[0016] This utility model's torque-transmitting reverse-lock safety connector improves upon existing safety release connectors. The advantages of this torque-transmitting reverse-lock safety connector are: by providing an anti-rotation keyway structure on the central tube and corresponding mating keyway structures on the upper connector and outer cylinder, the central tube, upper connector, and outer cylinder are locked in a rotational manner through the keyway fit. During retrieval, retrieval can be achieved by rotating the pipe stop at any angle. The keyway fit between the upper connector and outer cylinder allows for efficient torque transmission. When the lower pipe column is stuck, pressure is applied into the pipe to throw a ball, causing the shear pin to cut. The central tube descends, and the anti-rotation keyway structure of the central tube disengages from the mating keyway structure, releasing the locking relationship between the upper connector and outer cylinder. Reversing the pipe stop disengages the outer cylinder from the upper connector, thus releasing the outer cylinder. The torque between the upper connector and the outer cylinder is transmitted by locking the anti-rotation keyway structure of the central tube in conjunction with the keyway structures of the upper connector and the outer cylinder. Since the keyway structure can be as long as possible in the axial direction of the central tube, the structural strength is higher and the anti-rotation fit is more reliable. The locking failure will not occur during the use of the rotating tube column. Attached Figure Description

[0017] Figure 1 This is a schematic diagram of the structure of the torsion-transmitting buckle safety connector according to an embodiment of the present utility model;

[0018] Figure 2 for Figure 1 A schematic diagram of the structure at point AA.

[0019] In the diagram: 1. Upper connector; 2. Ball seat; 3. Shear pin; 4. Inverted outer tube; 5. Center tube; 6. Lower connector; 7. Clearance clearance; 8. Through hole. Detailed Implementation

[0020] The features and performance of this utility model will be further described in detail below with reference to the embodiments.

[0021] First, a general description of the technical solution of this utility model will be given:

[0022] Safety connectors are often used in conjunction with downhole fishing tubing or are equipped with fishing tools themselves. Existing safety release connectors use a locking sleeve to lock the petal-shaped limiting claw to the locking groove to achieve limiting and locking between the body and the release claw sleeve connector. Because the limiting claw is petal-shaped and located at the end of the release claw sleeve, the limiting claw is prone to breakage during the tightening process, resulting in limiting failure, affecting use, and having low structural strength.

[0023] This utility model designs a torque-transmitting reverse-clamp safety joint based on the above-mentioned problems. To ensure structural strength during use, withstand large torques, and guarantee the reliability of the safety joint, the following technical solution is adopted: A torque-transmitting reverse-clamp safety joint includes an upper joint, a central tube, and an outer cylinder. The upper joint is used to connect to the oil pipe and is located between the central tube and the outer cylinder. The central tube and the upper joint are connected by a shear pin, and the outer cylinder is connected to the upper joint by a reverse thread. By setting an anti-rotation keyway structure on the central tube and corresponding mating keyway structures on the upper joint and the outer cylinder, the central tube, the upper joint, and the outer cylinder are rotated and locked through the keyway mating. Torque transmission is achieved between the upper joint and the outer cylinder through the anti-rotation keyway structure of the central tube. Moreover, when a ball is thrown and pressed onto the ball seat of the central tube, the shear pin is cut off, causing the mating keyway structure of the central tube to disengage from the anti-rotation keyway structure, thus releasing the anti-rotation mating relationship between the upper joint and the outer cylinder. The pipe is rotated in the opposite direction to disengage the outer cylinder from the upper joint, thereby releasing the outer cylinder.

[0024] Specific embodiments of the torque-transmitting reverse-clamp safety connector of this utility model:

[0025] The structural schematic diagram of the torque-transmitting reverse-clamp safety joint of this utility model is shown below. Figure 1-2 As shown, a torque-transmitting reverse-clamp safety connector includes an upper connector 1, a central tube 5, and an outer cylinder. The upper connector 1 is located between the central tube 5 and the outer cylinder. The central tube and the upper connector are connected by a shear pin 3. The upper end of the upper connector 1 has an external thread section for connecting to an oil pipe, and the lower end of the outer cylinder also has an external thread section for connecting to a retrieval string. The central tube 5 is guided and slidably disposed inside the upper connector 1. The outer cylinder and the upper connector 1 are connected by a reverse thread. The key feature of this invention is that the central tube 5 is provided with an anti-rotation keyway structure, and the upper connector 1 and the outer cylinder are correspondingly provided with mating keyway structures. Torque transmission between the upper connector and the outer cylinder is achieved through the anti-rotation keyway structure of the central tube.

[0026] In this embodiment, the anti-rotation keyway structure is the anti-rotation key, and the matching keyway structure is the anti-rotation keyway. Specifically, the central tube 5 is provided with an anti-rotation key facing the upper connector 1 and the outer cylinder. The upper connector 1 and the outer cylinder are correspondingly provided with anti-rotation keyways. Torque transmission between the upper connector 1 and the outer cylinder is achieved through the anti-rotation key of the central tube 5. When a ball is thrown and pressed onto the ball seat 2 of the central tube 5, the shear pin 3 is sheared to disengage the anti-rotation key of the central tube 5 from the anti-rotation keyway, thus releasing the anti-rotation fit between the upper connector 1 and the outer cylinder. Of course, in other embodiments, anti-rotation keys can also be provided on the upper connector 1 and the outer cylinder respectively, and anti-rotation keyways corresponding to the anti-rotation keys of the two structures can be provided on the central tube 5. When a ball is thrown and pressed onto the ball seat 2 of the central tube 5, the shear pin 3 is sheared to disengage the anti-rotation keys of both the upper connector 1 and the outer cylinder from the anti-rotation keyways of the central tube 5.

[0027] After the shear pin 3 is cut, in order to prevent the central tube 5 from detaching from the upper connector 1 so that the central tube 5 can be used again, preferably, a limiting boss is provided on the inner wall of the upper connector 1, and the upper end of the central tube 5 is provided with an anti-detachment outer edge that cooperates with the limiting boss. This is used to prevent the central tube 5 from detaching from the upper connector 1 during the downward movement. It is only necessary for the anti-rotation key of the central tube 5 to disengage from the anti-rotation keyway to release the anti-rotation cooperation between the upper connector 1 and the outer cylinder. In this way, the shear pin 3 can be reassembled by lifting the central tube 5 during the next use, and it can be reused.

[0028] Specifically, the outer cylinder includes an inverted outer tube 4 and a lower connector 6. The inverted outer tube 4 is connected to the upper connector 1 by a reverse thread to facilitate the release function. The inverted outer tube 4 is connected to the lower connector 6 by a forward thread, and the lower connector 6 is easy to assemble with the salvage tool and has higher compatibility. In this embodiment, the lower end of the central tube 5 is sealed to the lower connector 6, which provides a certain support for the lower end of the central tube 5.

[0029] Furthermore, to ensure the reliability of the connection between the upper connector 1 and the inverted outer tube 4 before it is released, preferably, the shear pin 3 is also radially mounted on the outer cylinder. Specifically, the upper connector 1 and the inverted outer tube 4 are also connected by the shear pin 3. In this way, the shear pin 3 strengthens the assembly between the upper connector 1 and the inverted outer tube 4, and can simultaneously cut off the outer cylinder when the tube needs to be discarded during reverse rotation, which is convenient to use. By using the same shear pin 3 to be mounted on the central tube 5, the upper connector 1, and the inverted outer tube 4, firstly, the assembly is convenient and the structure is simple; secondly, the connection points of the central tube 5 and the upper connector 1, and the upper connector 1 and the inverted outer tube 4 are at the same radial height, and the fixed position is the same during rotation. There will be no deviation in the force at different positions during the rotation of the tube, ensuring a better assembly. Of course, in other embodiments, the shear pin between the upper connector and the outer cylinder and the shear pin between the central tube and the outer cylinder can be set at different radial positions.

[0030] Specifically, to facilitate the pressing of the ball into the tube, preferably, a ball seat 2 is detachably connected to the central tube 5. After the ball is thrown, it falls onto the ball seat 2 to achieve a seal. An anti-detachment outer edge is set on the ball seat 2 so that when it is necessary to release the ball, pressure is applied into the tube to cut the shear pin 3, causing the central tube 5 to descend. The anti-rotation key of the central tube 5 disengages from the anti-rotation keyway of the upper connector 1 and the outer cylinder. After the anti-detachment outer edge reaches the limiting boss, a stop engagement is formed, which is convenient to use and ensures good sealing after the ball is thrown. Of course, in other embodiments, the ball can also be thrown directly to the upper end of the central tube 5 to achieve the sealing effect inside the tube. The upper end of the central tube 5 constitutes the ball seat for throwing the ball.

[0031] Furthermore, to ensure better torque transmission from the anti-rotation key, in this embodiment, the anti-rotation key is preferably integrally formed with the central tube 5. This results in higher structural strength of the anti-rotation key and more reliable torque transmission between the upper connector 1 and the outer cylinder. To ensure a good anti-rotation effect, the anti-rotation key can be extended as far as possible along the axial direction of the central tube, achieving better assembly results. Of course, in other embodiments, the anti-rotation key can also be assembled by fixing it to the central tube 5.

[0032] In this embodiment, preferably, the anti-rotation key is a spline, with the splines evenly distributed circumferentially on the central tube 5. Correspondingly, spline grooves are evenly distributed circumferentially on the upper connector 1 and the outer cylinder. This improves the anti-rotation effect between the upper connector 1 and the outer cylinder, increases the reliability of torque transmission, and extends service life. Of course, in other embodiments, the anti-rotation key can also be a regular flat key, with corresponding flat keyways on the upper connector 1 and the outer cylinder, which can also ensure good torque transmission.

[0033] Since the wall thickness at the spline position of the central tube 5 is greater than that at other positions, to facilitate the installation of the shear pin 3 and ensure the structural reliability of the shear pin 3, it is preferable that the shear pin 3 is positioned corresponding to the spline position. This results in a larger wall thickness at the spline position of the central tube 5, facilitating the assembly of the shear pin 3 and minimizing its impact on the structural strength of the central tube 5. Of course, if the wall thickness and structural strength are high at other positions of the central tube, the shear pin 3 can also be positioned at a different location on the central tube than at the spline position.

[0034] In this embodiment, during the downward movement of the central tube 5, in order to ensure the reliability of the downward movement of the central tube 5 and allow the spline to smoothly disengage from the spline groove, a clearance gap 7 is provided between the central tube 5 and the outer cylinder below the spline, so that the spline can slide into the clearance gap 7. In order to ensure the communication between the inside of the tube and the outside, and to prevent the sealing situation from affecting the downward movement of the central tube 5 when the bottom of the tube column is blocked, preferably, a through hole 8 is provided on the outer cylinder to communicate with the clearance gap 7. In this way, the space below the ball seat 2 after the central tube 5 is thrown will always ensure smooth airflow and will not affect the downward movement of the central tube 5, thus improving reliability.

[0035] In use, the torque-transmitting reverse-clamp safety joint of this utility model connects the oil pipe to the upper connector 1. The spline on the central tube 5 is located within the spline groove of the upper connector 1 and the reverse-clamp outer tube 4, locking the upper connector 1 and the reverse-clamp outer tube 4, thus enabling torque transmission. After the tubing is lowered into position, flushing and retrieval are performed first. If retrieval is still unsuccessful, the tubing can be rotated as needed to improve the success rate of retrieval, since the upper connector 1 and the reverse-clamp outer tube 4 are locked. When the retrieval part is stuck or needs to be released, a ball is thrown into the central tube 5, and the ball is allowed to land in the tubing. After seat 2 is in place, pressure is applied to the oil pipe. When the pressure reaches 11 MPa, the shear pin 3 is sheared off, the connection between the central tube 5 and the upper connector 1 fails, and the central tube 5 descends. The spline on the central tube 5 disengages from the spline groove of the upper connector 1 and the reverse outer tube 4, and the locking of the upper connector 1 and the reverse outer tube 4 is released. The central tube 5 is stopped when it descends to the limit protrusion, and then the entire tubing is rotated in the opposite direction. Under a torque of 1750 N•m, the shear pin 3 is sheared off, and the reverse threads of the upper connector 1 and the reverse outer tube 4 are disengaged, thus achieving release.

[0036] Through the above description of specific embodiments of the torque-transmitting reverse-lock safety connector of this utility model, it can be seen that the torque-transmitting reverse-lock safety connector of this utility model has an anti-rotation keyway structure on the central tube and corresponding mating keyway structures on the upper connector and the outer cylinder. This allows the central tube, the upper connector, and the outer cylinder to form a rotation lock through the keyway mating. During the retrieval process, the pipe can be rotated at any angle to achieve retrieval. The upper connector and the outer cylinder can transmit torque well through the keyway mating. When the lower pipe column is stuck, it is necessary to press the ball into the pipe to cut the shear pin. The central tube moves downward, and the anti-rotation keyway structure of the central tube disengages from the mating keyway structure, thus releasing the locking relationship between the upper connector and the outer cylinder. The pipe can then be rotated in the opposite direction to disengage the outer cylinder from the upper connector, thereby releasing the outer cylinder. The torque between the upper connector and the outer cylinder is transmitted by locking the anti-rotation keyway structure of the central tube in conjunction with the keyway structures of the upper connector and the outer cylinder. Since the keyway structure can be as long as possible in the axial direction of the central tube, the structural strength is higher and the anti-rotation fit is more reliable. The locking failure will not occur during the use of the rotating tube column.

[0037] The above description is only a preferred embodiment of the present utility model and is not intended to limit the present utility model. The patent protection scope of the present utility model shall be determined by the claims. Similarly, any equivalent structural changes made based on the description and drawings of the present utility model shall also be included within the protection scope of the present utility model.

Claims

1. A torsion-transmitting safety connector, comprising an upper connector, a central tube, and an outer cylinder, wherein the upper connector is located between the central tube and the outer cylinder, characterized in that, The outer cylinder includes an inverted outer tube and a lower connector. The inverted outer tube is connected to the upper connector by a reverse thread, and the inverted outer tube is connected to the lower connector by a forward thread. The outer circumference of the central tube has an anti-rotation key. The upper connector and the inverted outer tube are respectively provided with anti-rotation keyways. Torque is transmitted between the upper connector and the outer cylinder through the anti-rotation key of the central tube. The central tube and the upper connector are connected by a shear pin. The shear pin is set corresponding to a spline and is installed on the inverted outer tube, the upper connector and the central tube through the same shear pin. The inner wall of the upper connector is provided with a limiting boss. The upper end of the central tube is provided with an anti-detachment outer edge that cooperates with the limiting boss to prevent the central tube from detaching from the upper connector during the downward movement. The lower end of the central tube is sealed to the lower connector. The ball seat is detachably connected to the central tube. The anti-detachment outer edge is provided on the ball seat. When a ball is thrown and pressed onto the ball seat of the central tube, the shear pin is sheared to disengage the anti-rotation keyway structure of the central tube from the keyway structure, thereby releasing the anti-rotation fit between the upper connector and the outer cylinder.

2. The torque-transmitting reverse-clamp safety connector according to claim 1, characterized in that, The anti-rotation key is integrally formed with the central tube.

3. The torque-transmitting reverse-clamp safety connector according to claim 2, characterized in that, The anti-rotation key is a spline.

4. The torque-transmitting reverse-clamp safety connector according to any one of claims 1-3, characterized in that, A clearance is provided between the central tube and the outer cylinder below the anti-rotation key to allow the anti-rotation key to slide in. A through hole is provided on the outer cylinder to communicate with the clearance.

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