Safety slip for natural gas drilling

Abstract

The invention discloses a safety slip for natural gas drilling, and relates to the technical field of petroleum drilling equipment, the safety slip comprises a plurality of slip pieces hinged through hinge pin shafts, a tooth plate sleeve arranged in the middles of the slip pieces, and slip inserts mounted in the tooth plate sleeve, and the middles of the slip inserts are provided with moving grooves extending transversely; and moving teeth capable of moving in the radial direction are arranged in the moving grooves in a sliding mode, two parallel transverse rods are inserted into the back sides of the moving teeth, clamping blocks are fixedly arranged on the outer wall of the tooth plate sleeve, and pushing assemblies are installed on the clamping blocks. When the main slip loses efficacy and the drill rod impacts downwards, the moving teeth of the safety slip rapidly extend out in the radial direction of the moving groove under the action of the pushing assembly and are in interference fit with the outer wall of the drill rod, at the moment, the moving teeth and the original slip teeth share impact loads together, high-strength impact force originally concentrated on a single point is dispersed to a plurality of meshing contact areas, and the safety of the drill rod is improved. And the deformation or fracture of the slip insert caused by local stress concentration is effectively avoided.

Description

Technical Field

[0001] The present invention relates to a control drill pipe assembly in the field of oil drilling equipment, and particularly to a safety slip for natural gas drilling. Background Art

[0002] In drilling operations, the safety slip and the master slip together constitute the core components of the drill pipe fixing control system. The master slip is usually arranged on the upper part of the drill pipe. Its core function is to stably bear the axial load of the drill pipe and the dynamic pressure generated during the operation through the meshing of the slip teeth with the outer wall of the drill pipe, so as to ensure the verticality of the drill pipe and the stability of the operation. As a redundant protection device, the safety slip is arranged below the master slip. When the master slip works normally, the safety slip is in a non-loaded standby state; once the master slip fails due to wear, tooth failure or sudden abnormal load, the safety slip will automatically take over its role and control the uncontrolled fall of the drill pipe by meshing its own slip structure with the drill pipe, providing the last line of defense for operation safety.

[0003] However, when the master slip suddenly fails, the drill pipe moves downward rapidly under the action of gravity, driving the safety slip to rush down synchronously and collide violently with the wellhead platform or the ground. Since the instantaneous impact force far exceeds the conventional load, it is extremely easy to cause the meshing failure between the slip teeth of the safety slip and the drill pipe, posing a serious threat to personnel safety and equipment integrity. Summary of the Invention

[0004] The purpose of the present invention is to solve the defect that the safety slip is extremely easy to have meshing failure under special circumstances in the prior art, and to propose a safety slip for natural gas drilling.

[0005] In order to solve the problems existing in the prior art, the present invention adopts the following technical solutions: A safety slip for natural gas drilling, comprising a plurality of slip pieces hinged by hinge pins, a tooth plate sleeve arranged in the middle of the slip pieces, and slip teeth installed in the tooth plate sleeve. A transverse moving groove is formed in the middle of the slip teeth. A movable tooth that can move radially is slidably arranged in the moving groove. Two parallel cross bars are inserted into the back side of the movable tooth. A clamping block is fixedly arranged on the outer wall of the tooth plate sleeve. A pushing assembly is installed on the clamping block. The ends of the cross bars sequentially pass through the tooth plate sleeve and the clamping block and are connected with the pushing assembly. The pushing assembly pushes the cross bars to make the movable tooth radially extend along the moving groove and form an interference fit with the outer wall of the drill pipe.

[0006] Preferably, the pushing assembly includes a connecting frame sleeved on the clamping block. One end of the connecting frame away from the clamping block is located outside the slip piece. A vertical rod is slidably arranged vertically at one end of the connecting frame away from the clamping block. The inclined surface of the vertical rod is attached to the inclined surface of the cross bar.

[0007] Preferably, two connecting bars are symmetrically arranged at the top and bottom of the inner wall of the connecting frame, and connecting grooves adapted to the connecting bars are formed at the top and bottom of the clamping block.

[0008] Preferably, the top and bottom of the connecting frame are triangular in shape, and fixing grooves vertically penetrate through the top and bottom of the connecting frame. The fixing grooves are parallel to the grooves on the clamping tiles and the clamping blocks.

[0009] Preferably, a retaining ring is fixedly arranged on the outer wall of the vertical rod, and the retaining ring is located inside the connecting frame.

[0010] Preferably, a rubber pad is fixedly arranged on the lower surface of the retaining ring.

[0011] Preferably, limiting grooves are formed on both sides of the moving groove, and limiting blocks are fixedly arranged on both sides of the moving teeth. The limiting blocks are located in the limiting grooves.

[0012] Preferably, a reinforcing block is fixedly arranged on the side of the moving teeth away from the cross bar.

[0013] Compared with the prior art, the beneficial effects of the present invention are as follows: 1. In the present invention, the safety slip significantly reduces the risk of damage to the slip system caused by sudden impact by adding a radially slidable moving teeth structure and an active pushing component. When the main slip fails and the drill pipe moves downward, the moving teeth of the safety slip quickly extend radially along the moving groove under the action of the pushing component and form an interference fit with the outer wall of the drill pipe. At this time, the moving teeth and the original slip teeth jointly share the impact load, dispersing the high-intensity impact force originally concentrated at a single point to multiple meshing contact areas, effectively avoiding the deformation or fracture of the slip teeth caused by local stress concentration; 2. In the present invention, the lower end of the vertical rod is located below the clamping tiles. When the safety slip drives the drill pipe to descend, the lower part of the vertical rod contacts the wellhead platform or the ground first, avoiding direct impact damage to the components in the safety slip, controlling the descent of the drill pipe, and improving safety. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] The drawings described herein are used to provide a further understanding of the present invention, and constitute a part of this application. The schematic embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation to the present invention. In the drawings: Figure 1 is a schematic diagram of the overall structure of the present invention; Figure 2 is a schematic diagram of the back structure of the present invention; Figure 3 is a schematic diagram of the structure of the pushing component of the present invention; Figure 4 is an exploded structure diagram of the present invention; Figure 5 is an exploded structure diagram of the present invention.

[0015] Reference numerals in the figure: 1, die holder sleeve; 11, clamping tile; 12, clamping jaw; 13, clamping block; 14, moving groove; 15, moving tooth; 16, cross bar; 2, pushing assembly; 21, connecting frame; 22, vertical bar; 3, connecting groove; 31, connecting strip; 4, fixing groove; 5, retaining ring; 6, rubber pad; 7, limiting groove; 71, limiting block; 8, reinforcing block. Specific embodiments

[0016] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments.

[0017] Embodiment: This embodiment provides a safety slip for natural gas drilling. Refer to Figures 1-5 , specifically, it includes a plurality of clamping tiles 11 hinged by hinge pins, a die holder sleeve 1 provided in the middle of the clamping tiles 11, and a clamping jaw 12 installed in the die holder sleeve 1. A horizontally extending moving groove 14 is provided in the middle of the clamping jaw 12. A radially movable moving tooth 15 is slidably provided in the moving groove 14. Two parallel cross bars 16 are inserted into the back side of the moving tooth 15. A clamping block 13 is fixedly provided on the outer wall of the die holder sleeve 1. A pushing assembly 2 is installed on the clamping block 13. The end of the cross bar 16 sequentially passes through the die holder sleeve 1 and the clamping block 13 and is connected to the pushing assembly 2. The pushing assembly 2 pushes the cross bar 16 to make the moving tooth 15 radially extend along the moving groove 14 and form an interference fit with the outer wall of the drill pipe.

[0018] In this embodiment, the connection method of the safety slip is as follows: Install the clamping jaw 12 with the moving tooth 15 in the die holder sleeve 1, then assemble the clamping tiles 11 into upper and lower layers through connecting pins, install the clamping block 13 on the die holder sleeve 1 in the middle of the two layers of clamping tiles 11 and fit it with the middle parts of the upper and lower layers of clamping tiles 11. Then insert the two cross bars 16 from the end of the clamping block 13 and connect them to the groove on the back of the moving tooth 15. Then sleeved the pushing assembly 2 on the clamping block 13. Finally, adjust the clamping tiles 11 into a ring shape so that all the clamping jaws 12 are in contact with the outer wall of the drill pipe, and then lock it through the adjusting screw to clamp the drill pipe. By providing a moving groove 14 in the middle of the clamping jaw 12 and arranging a moving tooth 15 with a length less than that of the moving groove 14 in the moving groove 14, when the drill pipe drives the safety slip to quickly descend, the pushing assembly 2 is used to push the cross bar 16, so that the cross bar 16 pushes the moving tooth 15 to closely adhere to the outer wall of the drill pipe, which is used to disperse the instantaneous impact force borne by the entire clamping jaw 12 and avoid the meshing failure between the clamping jaw 12 and the drill pipe.

[0019] In the specific implementation process, such as Figure 3 and Figure 4As shown, the pushing component 2 includes a connecting frame 21. The connecting frame 21 is sleeved on the clamping block 13. One end of the connecting frame 21 away from the clamping block 13 is located outside the clamping tile 11. A vertical rod 22 is vertically slidably arranged at one end of the connecting frame 21 away from the clamping block 13. The inclined surface of the vertical rod 22 is in contact with the inclined surface of the cross rod 16.

[0020] In this embodiment, after the end of the connecting frame 21 is sleeved on the clamping block 13, the inclined surfaces of the cross rod 16 and the vertical rod 22 are in contact. The lower end of the vertical rod 22 is located below the clamping tile 11. When the safety clamping tile drives the drill pipe to descend, the lower part of the vertical rod 22 contacts the wellhead platform or the ground first. After the vertical rod 22 contacts, it will move upward. The vertical rod 22 pushes the cross rod 16 to move horizontally through the inclined surface, and the cross rod 16 then pushes the moving tooth 15 to closely fit with the outer wall of the drill pipe, reducing the force borne by the entire clamping jaw 12.

[0021] In the specific implementation process, as Figure 3 and Figure 4 shown, two connecting strips 31 are symmetrically arranged at the top and bottom of the inner wall of the connecting frame 21. Connecting grooves 3 adapted to the connecting strips 31 are formed at the top and bottom of the clamping block 13.

[0022] In this embodiment, by setting the connecting strips 31 and the connecting grooves 3, the assembly speed between the connecting frame 21 and the clamping block 13 is improved, and the connection stability between the connecting frame 21 and the clamping block 13 is increased.

[0023] In the specific implementation process, as Figure 3 and Figure 4 shown, the top and bottom of the connecting frame 21 are triangular in shape. Fixing grooves 4 are vertically penetrated through the top and bottom of the connecting frame 21. The fixing grooves 4 are parallel to the grooves on the clamping tile 11 and the clamping block 13.

[0024] In this embodiment, the triangular shapes provided at the top and bottom of the connecting frame 21 are adapted to the inclined surface in the middle of the clamping tile 11, so that the clamping block 13 is in contact with the clamping tile 11, increasing the stability of the tooth plate sleeve 1 and the clamping jaw 12. Since the clamping block 13 on the tooth plate sleeve 1 and the clamping tile 11 are fixed by passing an opening pin through, fixing grooves 4 aligned with the clamping block 13 and the clamping tile 11 are added on the connecting frame 21, so that the connecting frame 21, the clamping tile 11 and the clamping block 13 are fixed together.

[0025] In the specific implementation process, as Figure 3 and Figure 4 shown, a retaining ring 5 is fixedly arranged on the outer wall of the vertical rod 22. The retaining ring 5 is located inside the connecting frame 21.

[0026] In this embodiment, the vertical rod 22 is located in the connecting frame 21 through the retaining ring 5 and cannot move downward, but can only move upward.

[0027] In the specific implementation process, as Figure 3 andFigure 4 As shown, a rubber pad 6 is fixedly provided on the lower surface of the retaining ring 5.

[0028] In this embodiment, by providing the rubber pad 6, a certain degree of buffering is carried out on the vertical rod 22 to reduce the rebound of the pushing assembly 2.

[0029] During the specific implementation process, as Figure 1 and Figure 5 shown, limiting grooves 7 are provided on both sides of the moving groove 14, and limiting blocks 71 are fixedly provided on both sides of the moving tooth 15, and the limiting blocks 71 are located in the limiting grooves 7.

[0030] In this embodiment, it is used to limit the moving direction of the moving tooth 15. Since the contact surfaces of the moving tooth 15 and the slip teeth 12 with the drill pipe are arc surfaces, it is avoided that the moving tooth 15 has a lateral dislocation situation, resulting in a deviation in the contact surface with the drill pipe and reducing the friction force.

[0031] During the specific implementation process, as Figure 1 and Figure 5 shown, a reinforcing block 8 is fixedly provided on the side of the moving tooth 15 away from the cross bar 16.

[0032] In this embodiment, the material of the reinforcing block 8 is synthetic rubber, which is used to enhance the fitting degree with the drill pipe and increase the friction force.

[0033] The above is only a preferred specific implementation manner of the present invention, but the protection scope of the present invention is not limited thereto. Any person skilled in the art within the technical scope disclosed by the present invention, according to the technical solution and inventive concept of the present invention, makes equivalent substitutions or changes, and should be covered within the protection scope of the present invention.

Claims

1. A safety slip for natural gas drilling, comprising a plurality of slip pieces (11) hingedly connected by a hinge pin, a tooth plate sleeve (1) arranged in the middle of the slip pieces (11), and a slip tooth (12) installed in the tooth plate sleeve (1), characterized in that: A laterally extending movable groove (14) is provided in the middle of the slip tooth (12); a radially movable movable tooth (15) is slidably arranged in the movable groove (14); two parallel cross bars (16) are inserted on the back side of the movable tooth (15); a clamping block (13) is fixedly arranged on the outer wall of the tooth plate sleeve (1); a pushing component (2) is installed on the clamping block (13); the end of the cross bar (16) passes through the tooth plate sleeve (1) and the clamping block (13) in sequence and is connected to the pushing component (2); the pushing component (2) pushes the cross bar (16) to make the movable tooth (15) extend radially along the movable groove (14) and form an interference fit with the outer wall of the drill pipe.

2. A safety slip for natural gas drilling according to claim 1, characterized in that: The pushing assembly (2) comprises a connecting frame (21), the connecting frame (21) being sleeved on the clamping block (13), the end of the connecting frame (21) away from the clamping block (13) being located outside the clamping tile (11), the end of the connecting frame (21) away from the clamping block (13) being vertically slidably provided with a vertical rod (22), the inclined surface of the vertical rod (22) being in contact with the inclined surface of the cross rod (16).

3. A safety slip for natural gas drilling according to claim 2, characterized in that: Two connecting strips (31) are symmetrically arranged at the top and bottom of the inner wall of the connecting frame (21), and connecting grooves (3) adapted to the connecting strips (31) are opened at the top and bottom of the clamping block (13).

4. A safety slip for natural gas drilling according to claim 2, characterized in that: The top and bottom of the connection frame (21) are in a triangular shape, and a fixing groove (4) vertically penetrates the top and bottom of the connection frame (21), and the fixing groove (4) is parallel to the grooves on the tile piece (11) and the block (13).

5. A safety slip for natural gas drilling according to claim 2, characterized in that: A retaining ring (5) is fixedly provided on the outer wall of the vertical rod (22), and the retaining ring (5) is located inside the connecting frame (21).

6. A safety slip for natural gas drilling according to claim 5, characterized in that: A rubber pad (6) is fixedly provided on the lower surface of the retaining ring (5).

7. A safety slip for natural gas drilling according to claim 1, characterized in that: Limiting grooves (7) are provided on both sides of the movable groove (14), and limiting blocks (71) are fixedly provided on both sides of the movable teeth (15), and the limiting blocks (71) are located in the limiting grooves (7).

8. The safety slip for natural gas drilling according to claim 1, characterized in that: A reinforcing block (8) is fixedly provided on a side of the movable tooth (15) away from the cross bar (16).

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