A test device for a rack and pinion underground tractor

Abstract

The utility model relates to a kind of test device of underground tractor, specifically relates to a kind of test device of rack and pinion underground tractor.The test device of rack and pinion underground tractor is constituted by tool casing A, left wedge rack, piston rod, driving piston and support piston;Tool casing A, tool casing B and tool casing C are fixedly connected by support connector pipe between each other;One end of tool casing C is equipped with cylinder barrel by assembly connector pipe;Piston rod is movably installed in assembly connector pipe;One end of piston rod is equipped with driving piston;The other end of piston rod is connected with right wedge rack;Right wedge rack is connected with left wedge rack.The test device of rack and pinion underground tractor, simple structure, reliable operation, overcome the problem of reducing drilling efficiency and tool conveying capacity of existing tractor for rack and pinion underground tractor, meet the needs of enterprise use.

Description

Technical Field

[0001] This utility model relates to a test device for a downhole traction device, specifically a test device for a gear and rack downhole traction device. Background Technology

[0002] In the field of petroleum engineering, horizontal well exploration and development can maximize the exposure of oil and gas reservoirs, significantly improve oil and gas extraction efficiency and ultimate recovery rate. Horizontal well technology has become the mainstream engineering technology for global exploration and development. Moreover, unconventional resources such as shale gas, due to their tight reservoirs and low permeability, are almost entirely explored, developed, and produced using horizontal wells. In my country, the horizontal displacement of shale gas development is around 2000m, while abroad it reaches 3000m, with some well shapes even resembling fishhooks. With the increase in horizontal displacement and horizontal sections of these wells, the issue of downhole extension has become a key technology and bottleneck restricting operational capabilities. Existing long-distance horizontal well traction devices not only increase tubing friction, reduce drilling efficiency and tool delivery capacity, but may also, in severe cases, lead to insufficient drilling depth and failure to deliver tools to the target location. Therefore, it is necessary to develop a test device for a new type of downhole traction device to simulate the working process of the new downhole traction device, laying a theoretical foundation for the new downhole traction device to solve the above-mentioned problems of existing traction devices. Summary of the Invention

[0003] The purpose of this utility model is to provide a test device for a rack and pinion downhole traction device that is simple in structure and easy to use, and can solve the problems of existing traction devices that reduce drilling efficiency and tool delivery capacity.

[0004] The technical solution of this utility model is: A test device for a rack and pinion downhole traction device comprises a tool casing A, a tool casing B, a tool casing C, a left wedge rack, a right wedge rack, a piston rod, a drive piston, and a support piston. Its features include: the tool casings A, B, and C, arranged at intervals, are fixedly connected to each other via support connecting pipes; drive assemblies are symmetrically and movably mounted on each support connecting pipe; a cylinder is mounted at one end of tool casing C via an assembly connecting pipe; a piston rod is movably mounted inside the assembly connecting pipe; a drive piston is mounted at one end of the piston rod via a locking nut; the other end of the piston rod extends into the interior of tool casing C and is connected to a right wedge rack via a support joint; the right wedge rack extends into the interior of tool casing B and is connected to a left wedge rack via a fastening bolt; one end of the left wedge rack extends into the interior of tool casing A and is mounted to a support piston via a locking nut; the right and left wedge racks are respectively engaged with the drive assemblies on their corresponding support connecting pipes.

[0005] The right wedge-shaped rack and the left wedge-shaped rack are each composed of a rack body; one end of the rack body is conical; the middle part of the two sides of the rack body is provided with clearance grooves, and the rack body on both sides of the clearance grooves is provided with drive teeth.

[0006] The rack body of the right wedge rack is staggered with the rack body of the left wedge rack at a 90° angle.

[0007] The support pipe consists of two pipe joints, an assembly plate, and a limiting block; the two pipe joints are arranged symmetrically; the pipe joints are fixedly connected by the symmetrically arranged assembly plates; each assembly plate has a U-shaped opening arranged symmetrically, and a limiting block is provided at the upper end of each U-shaped opening; a drive assembly is installed in the U-shaped opening below the limiting block.

[0008] Each of the aforementioned pipe joints is equipped with a buffer spring inside.

[0009] The support pipe between tool sleeve A and tool sleeve B is staggered with the support pipe between tool sleeve B and tool sleeve C at 90°.

[0010] The drive assembly consists of a drive shaft, a positioning collar, a one-way bearing, a friction wheel, and a drive gear. The drive shaft, which is stepped, has a one-way bearing mounted in the middle via a flat key. A friction wheel is mounted on the circumference of the one-way bearing. Drive gears are mounted on both sides of the one-way bearing via flat keys. A positioning collar is mounted on one side of each drive gear via a snap ring, and each positioning collar is in contact with the drive gear on one side.

[0011] Each positioning collar is provided with an assembly ring groove, and the positioning collar is movably connected to the U-shaped opening through the assembly ring groove; a return spring is provided between the limit block and the positioning collar.

[0012] The supporting piston is slidably and sealingly connected to the inner wall of the tool sleeve A.

[0013] One end of the support joint is threaded to the piston rod; the other end of the support joint is threaded to the right wedge rack; a sealing ring is provided on the circumferential surface of the support joint; the support joint is slidably sealed to the inner wall of the tool sleeve C through the sealing ring; and multiple balance holes are regularly arranged on the support joint.

[0014] Pressure holes are provided on the cylinders on both sides of the drive piston.

[0015] The piston rod is slidably and sealed to the assembly pipe.

[0016] One end of the cylinder and one end of the tool sleeve A are respectively threaded with a sealing end cap, and the sealing end cap connected to the tool sleeve A is provided with a vent hole.

[0017] The tool sleeves A, B, and C are respectively fixedly connected to their corresponding support pipes by set screws.

[0018] The advantages of this utility model are: The test device for the rack and pinion downhole traction device has a simple structure and reliable operation. During operation, the piston rod drives the right and left wedge racks to reciprocate, and the entire test device can be driven forward intermittently through the friction wheel. The operation of the rack and pinion downhole traction device was simulated, and the problem of reduced drilling efficiency and tool delivery capacity of existing traction devices was verified, thus meeting the needs of enterprises. Attached Figure Description

[0019] Figure 1 This is a schematic diagram of the main structure of this utility model; Figure 2 for Figure 1 Schematic diagram of the structure in the AA direction; Figure 3 for Figure 2 Schematic diagram of the structure in the middle BB direction; Figure 4 for Figure 2 Schematic diagram of the CC-axis structure; Figure 5 for Figure 2 Schematic diagram of the structure in the DD direction; Figure 6 for Figure 2 Schematic diagram of the structure in the middle EE direction; Figure 7 This is a schematic diagram of the drive assembly of this utility model; Figure 8 This is a schematic diagram of the main structure of the left and right wedge-shaped racks of this utility model; Figure 9 This is a top view schematic diagram of the left and right wedge-shaped racks of this utility model; Figure 10 This is an isometric structural diagram of the left wedge-shaped rack of this utility model; Figure 11 This is an isometric structural diagram of the support pipe of this utility model; Figure 12 This is a front view schematic diagram of the support pipe of this utility model.

[0020] In the diagram: 1. Tool sleeve A, 2. Tool sleeve B, 3. Tool sleeve C, 4. Left wedge rack, 5. Right wedge rack, 6. Piston rod, 7. Drive piston, 8. Support piston, 9. Support connector, 10. Assembly connector, 11. Cylinder, 12. Locking nut, 13. Support joint, 14. Fastening bolt, 15. Set screw, 16. Rack body, 17. Clearance groove, 18. Drive gear, 19. Pipe joint, 20. Assembly plate, 21. Limiting block, 22. U-shaped opening, 23. Buffer spring, 24. Drive shaft, 25. Positioning collar, 26. One-way bearing, 27. Friction wheel, 28. Drive gear, 29. Snap ring, 30. Assembly ring groove, 31. Sealing ring, 32. Balance hole, 33. Pressure hole, 34. Sealing end cap, 35. Vent hole. Detailed Implementation

[0021] The test device for the rack and pinion downhole traction device consists of tool casing A1, tool casing B2, tool casing C3, left wedge rack 4, right wedge rack 5, piston rod 6, drive piston 7, and support piston 8.

[0022] Tool sleeves A1, B2, and C3, arranged at intervals, are fixedly connected to each other via support tubes 9; tool sleeves A1, B2, and C3 are respectively fixedly connected to their corresponding support tubes 9 via set screws 15. The purpose of the set screws 15 is to fix the support tubes 9 to each tool sleeve in place, preventing them from becoming loose.

[0023] The support pipe 9 consists of two pipe fittings 19, an assembly plate 20, and a limiting block 21. The two pipe fittings 19 are arranged symmetrically. Each pipe fitting 19 is threaded to its corresponding tool sleeve. The pipe fittings 19 are fixedly connected to each other by the symmetrically arranged assembly plates 20. Each assembly plate 20 has a symmetrically arranged U-shaped opening 22, and a limiting block 21 is provided at the upper end of each U-shaped opening 22 (see the instruction manual appendix). Figure 11 and 12 ).

[0024] The drive assembly is housed in the symmetrically arranged U-shaped openings 22 below the limit blocks 21 of each support pipe 9. The drive assembly consists of a drive shaft 24, a positioning collar 25, a one-way bearing 26, a friction wheel 27, and a drive gear 28. The one-way bearing 26 is mounted on the middle of the stepped shaft 24 via a flat key. The friction wheel 27 is mounted on the circumference of the one-way bearing 26. When the drive shaft 24 rotates forward, it can drive the outer ring and the friction wheel 27 to rotate together through the inner ring of the one-way bearing 26. When the drive shaft 24 rotates in reverse, driving the inner ring of the one-way bearing 26 to rotate, the inner ring of the one-way bearing 26 cannot transmit torque to the outer ring and the friction wheel 27, thus preventing the drive shaft 24 from driving the friction wheel 27 to rotate in reverse.

[0025] One-way bearing 26 has drive gears 28 mounted on both sides via flat keys; each drive gear 28 has a locating collar 25 mounted on one side via a snap ring 29, and each locating collar 25 is in contact with the drive gear 28 on one side (see instruction manual appendix). Figure 7 With this configuration, when the drive shaft 24 rotates, it can drive the drive gear 28, the positioning collar 25, and the one-way bearing 26 to rotate synchronously.

[0026] Each positioning collar 25 is provided with an assembly ring groove 30, and the positioning collar 25 is movably connected to the U-shaped opening 22 through the assembly ring groove 30. The purpose of providing the assembly ring groove 30 is to limit each drive assembly within the U-shaped opening 22, so that the drive assembly can only move up and down within the U-shaped opening 22.

[0027] A return spring (not shown in the figure) is provided between the limit stop 21 and the positioning collar 30. The purpose of providing the return spring is to ensure that each drive assembly always maintains a tendency to move towards the center under the elastic force of the return spring, thereby forcing the transmission gear 28 of each drive assembly to always maintain meshing with the drive teeth 18 on the corresponding right wedge rack 5 or left wedge rack 4.

[0028] Each pipe joint 19 is equipped with a buffer spring 23. The purpose of the buffer spring 23 is to provide a certain buffering force to the right wedge rack 5 and the left wedge rack 4 when they reach their limit position during reciprocating motion, so as to avoid damage to the joints and support joints 13 on the right wedge rack 5 and the left wedge rack 4 when they directly contact the pipe joint 19.

[0029] The support pipe 9 between tool sleeve A1 and tool sleeve B2 is staggered with the support pipe 9 between tool sleeve B2 and tool sleeve C3 at 90°. The purpose of this arrangement is to make the drive assemblies mounted on each support pipe 9 staggered, so that each drive assembly is subjected to more balanced force when driving the test device forward at multiple points.

[0030] One end of the tool sleeve C3 is fitted with a cylinder 11 via an assembly connector 10. A sealing end cap 34 is threaded onto one end of the cylinder 11 and one end of the tool sleeve A1, respectively. A vent hole 35 is provided on the sealing end cap 34 connected to the tool sleeve A1. The purpose of providing the vent hole 35 is to allow the tool sleeve A1 to maintain communication with the outside world through the vent hole 35, thereby avoiding the problem of "pressure buildup" within the tool sleeve A1 hindering the movement of the support piston 8 during its leftward movement.

[0031] A piston rod 6 is movably installed inside the assembly connector 10; the piston rod 6 is slidably and sealingly connected to the assembly connector 10. A drive piston 7 is mounted on one end of the piston rod 6 via a locking nut 12; pressure holes 33 are respectively provided on the cylinders 11 on both sides of the drive piston 7. During operation, pressure is applied or released into the cylinders 11 through the pressure holes 33, thereby driving the piston rod 6 to move back and forth via the drive piston 7.

[0032] The other end of the piston rod 6 extends into the interior of the tool sleeve C3 and is connected to the right wedge rack 5 via the support joint 13; one end of the support joint 13 is threaded to the piston rod 6; the other end of the support joint 13 is threaded to the right wedge rack 5; a sealing ring 31 is provided on the circumferential surface of the support joint 13; the support joint 13 is slidably sealed to the inner wall of the tool sleeve C3 through the sealing ring 31; the support joint 13 has the function of supporting the piston rod 6 and the right wedge rack 5, thereby avoiding the problem of deformation when the piston rod 6 and the right wedge rack 5 are too long and have no support points.

[0033] The support joint 13 has multiple balance holes 32 arranged in a regular pattern. The purpose of setting the balance holes 32 is to connect the left and right spaces of the support joint 13 through the balance holes 32, thereby balancing the pressure; thus avoiding the problem of "pressure buildup" on the left and right sides of the support joint 13 during operation due to pressure imbalance.

[0034] The right wedge rack 5 extends into the tool sleeve B2 and is connected to the left wedge rack 4 by a fastening bolt 14. The right wedge rack 5 and the left wedge rack 4 are each composed of a rack body 16. One end of the rack body 16 is tapered. Alternating clearance grooves 17 are provided in the middle of the two sides of the rack body 16, and drive teeth 18 are provided on the rack body 16 on both sides of the clearance grooves 17. The purpose of providing the clearance grooves 17 is to provide movement space for the friction wheel 27, so that the friction wheel 27 can move freely during the operation of the drive assembly, thereby avoiding the problem of the rack body 16 obstructing the rotation of the friction wheel 27.

[0035] Each drive tooth 18 on the right wedge rack 5 and the left wedge rack 4 meshes with the transmission gear 28 on the corresponding drive assembly. During the reciprocating motion of the right wedge rack 5 and the left wedge rack 4, the corresponding drive assembly can be driven to move through the drive teeth 18 and the transmission gear 28.

[0036] The rack body 16 of the right wedge rack 5 is staggered with the rack body 16 of the left wedge rack 4 at a 90° angle (see the instruction manual appendix). Figure 8 and 9 The purpose of this arrangement is to enable each drive assembly to maintain a meshing connection with the corresponding left wedge rack 4 and right wedge rack 5, so that when the rack body 16 of the right wedge rack 5 moves, it can drive each drive assembly to move.

[0037] One end of the left wedge-shaped rack 4 extends into the interior of the tool sleeve A1 and is fitted with a support piston 8 via a locking nut 12; the support piston 8 is slidably and sealingly connected to the inner wall of the tool sleeve A1. The support piston 8 supports the left wedge-shaped rack 4, thereby preventing deformation when the left wedge-shaped rack 4 is too long.

[0038] When the test device for the rack and pinion downhole traction device is in operation, the test device is first placed inside the corresponding casing, and then the pressure hole 33 on the cylinder 11 is connected to the external hydraulic station.

[0039] After the test device is assembled, the hydraulic station is started to pressurize the cylinder 11 through the right pressure hole 33 and act on the drive piston 7. After being pressed, the drive piston 7 drives the right wedge rack 5 and the left wedge rack 4 to move from right to left through the piston rod 6.

[0040] As the right wedge rack 5 and left wedge rack 4 move from right to left, their side drive teeth 18 drive the corresponding drive assembly's transmission gear 28 to rotate, which in turn drives the drive shaft 24 to rotate clockwise. During the clockwise rotation of the drive shaft 24, the one-way bearing 26 drives the friction wheel 27 to rotate. Simultaneously, during this process, the right wedge rack 5 and left wedge rack 4 gradually transition from thinner sections to thicker sections, driving the corresponding drive assemblies to move. This pushes each drive assembly to expand radially. When the thicker sections of the right wedge rack 5 and left wedge rack 4 contact each drive assembly, each drive assembly expands to its maximum position. At this point, the friction wheel 27 of each drive assembly contacts the sleeve. Subsequently, under the frictional action of the rotating friction wheel 27, the test device moves forward as a whole within the sleeve.

[0041] When the drive piston 7 pushes the piston rod 6 to move the right wedge rack 5 and the left wedge rack 4 to the left limit position, the hydraulic station is switched to pressurize the cylinder 11 through the left pressure hole 33 and release pressure through the right pressure hole 33. At this time, after the drive piston 7 is pressed, it drives the right wedge rack 5 and the left wedge rack 4 to move from left to right through the piston rod 6.

[0042] During this process, the right wedge rack 5 and the left wedge rack 4 drive the corresponding drive assembly's transmission gear 28 and transmission shaft 24 to reverse direction via the drive gear 18. During the reverse rotation of the transmission shaft 24, the inner ring of the one-way bearing 26 rotates, preventing the inner ring of the one-way bearing 26 from transmitting torque to the outer ring and friction wheel 27. Thus, the test device remains in a fixed position within the sleeve. Simultaneously, during this process, the right wedge rack 5 and the left wedge rack 4 gradually transition from their thicker sections to their thinner sections, driving the corresponding drive assembly to move. At this time, under the action of the return spring, each drive assembly contracts radially inward.

[0043] When the drive piston 7 pushes the piston rod 6, the right wedge rack 5, and the left wedge rack 4 to the right to their limit positions, each drive assembly remains connected to the thinnest end of the right wedge rack 5 and the left wedge rack 4. At this time, each drive assembly returns to its initial state. Then, by repeating the above actions, the test device can be made to move intermittently forward inside the casing, thereby simulating the working process of the gear rack downhole traction device downhole.

[0044] The test device for the rack and pinion downhole traction device has a simple structure and reliable operation. The operation of the rack and pinion downhole traction device was simulated, and the problem of reduced drilling efficiency and tool delivery capacity of the existing traction device was verified, which meets the needs of enterprises.

Claims

1. A test device for a rack and pinion downhole traction device, comprising a tool casing A (1), a tool casing B (2), a tool casing C (3), a left wedge rack (4), a right wedge rack (5), a piston rod (6), a drive piston (7), and a support piston (8); characterized in that: Tool sleeves A (1), B (2), and C (3) are arranged in a spaced-out manner and are fixedly connected to each other by support pipes (9); a drive assembly is symmetrically and movably mounted on each support pipe (9); a cylinder (11) is mounted on one end of tool sleeve C (3) through an assembly pipe (10); a piston rod (6) is movably mounted inside the assembly pipe (10); a drive piston (7) is mounted on one end of the piston rod (6) through a lock nut (12); the other end of the piston rod (6) extends to the tool... The inside of the sleeve C (3) is connected to a right wedge rack (5) via a support joint (13); the right wedge rack (5) extends into the inside of the tool sleeve B (2) and is connected to a left wedge rack (4) via a fastening bolt (14); one end of the left wedge rack (4) extends into the inside of the tool sleeve A (1) and is fitted with a support piston (8) via a locking nut (12); the right wedge rack (5) and the left wedge rack (4) are respectively engaged with the drive assembly on the corresponding support tube (9).

2. The test device for a rack and pinion downhole traction device according to claim 1, characterized in that: The right wedge rack (5) and the left wedge rack (4) are respectively composed of rack bodies (16); one end of the rack body (16) is conical; the middle part of the two sides of the rack body (16) is provided with clearance grooves (17), and the rack body (16) on both sides of the clearance grooves (17) is provided with drive teeth (18).

3. The test device for a gear and rack downhole traction device according to claim 2, characterized in that: The rack body (16) of the right wedge rack (5) and the rack body (16) of the left wedge rack (4) are arranged in a 90° staggered manner.

4. The test device for a gear and rack downhole traction device according to claim 3, characterized in that: The support pipe (9) consists of two pipe joints (19), an assembly plate (20) and a limiting block (21); the two pipe joints (19) are arranged symmetrically; the pipe joints (19) are fixedly connected by the symmetrically arranged assembly plate (20); each assembly plate (20) has a U-shaped opening (22) arranged symmetrically, and a limiting block (21) is provided at the upper end of each U-shaped opening (22); the U-shaped opening (22) below the limiting block (21) contains a drive assembly; each pipe joint (19) has a buffer spring (23) inside.

5. The test device for a rack and pinion downhole traction device according to claim 4, characterized in that: The support pipe (9) between tool sleeve A (1) and tool sleeve B (2) is staggered at 90° with the support pipe (9) between tool sleeve B (2) and tool sleeve C (3).

6. The test device for a gear and rack downhole traction device according to claim 5, characterized in that: The drive assembly consists of a drive shaft (24), a positioning collar (25), a one-way bearing (26), a friction wheel (27), and a drive gear (28). The drive shaft (24), which is in the form of a stepped shaft, is fitted with a one-way bearing (26) via a flat key in the middle. A friction wheel (27) is mounted on the circumferential surface of the one-way bearing (26). Drive gears (28) are mounted on both sides of the one-way bearing (26) via flat keys. A positioning collar (25) is mounted on one side of each drive gear (28) via a snap ring (29), and each positioning collar (25) is in contact with the drive gear (28) on one side.

7. The test device for a rack and pinion downhole traction device according to claim 6, characterized in that: Each positioning ring (25) is provided with an assembly ring groove (30), and the positioning ring (25) is movably connected to the U-shaped opening (22) through the assembly ring groove (30); a return spring is provided between the limiting block (21) and the positioning ring (25).

8. The test device for a rack and pinion downhole traction device according to claim 7, characterized in that: The supporting piston (8) is slidably and sealed to the inner wall of the tool sleeve A (1); one end of the supporting joint (13) is threaded to the piston rod (6); the other end of the supporting joint (13) is threaded to the right wedge rack (5); a sealing ring (31) is provided on the circumferential surface of the supporting joint (13); the supporting joint (13) is slidably and sealed to the inner wall of the tool sleeve C (3) through the sealing ring (31); a plurality of balance holes (32) are regularly arranged on the supporting joint (13).

9. The test apparatus for a gear and rack downhole traction device according to claim 8, characterized in that: The cylinders (11) on both sides of the driving piston (7) are respectively provided with pressure holes (33); the piston rod (6) is slidably sealed to the assembly pipe (10); a sealing end cap (34) is threadedly installed on one end of the cylinder (11) and one end of the tool sleeve A (1), and a vent hole (35) is provided on the sealing end cap (34) connected to the tool sleeve A (1); the tool sleeve A (1), tool sleeve B (2) and tool sleeve C (3) are respectively fixedly connected to the corresponding support pipe (9) by set screws (15).

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