Symmetrical underground coiled tubing tractor

Abstract

The utility model relates to the technical field of oil and gas field development, in particular to a symmetrical underground coiled tubing tractor which comprises a control unit, a traction unit and a traction unit. The two peristaltic units are symmetrically distributed on the two sides of the control unit and connected to the outer side of the central pipe; wherein the wriggling unit comprises a centralizer, an expansion brake device and a tensioning device, and the tensioning device is used for driving the expansion brake device to act; the symmetric underground coiled tubing tractor is simple in design, high in reliability and good in practicability, has strong traction force, can realize continuous operation, effectively solves the problem that the traction force is insufficient when the coiled tubing is placed in a deep well and an ultra-deep well environment by the existing tractor, and meanwhile, the device can apply certain drilling pressure and is convenient for taking out the coiled tubing. And when the coiled tubing is recycled, the control unit outputs an opposite action time sequence to be matched with the recycling operation of the coiled tubing. The device is suitable for traction operation of coiled tubing in deep well and ultra-deep well environments.

Description

Technical Field

[0001] The utility model relates to the technical field of oil and gas field development, in particular to a symmetric downhole coiled tubing tractor. Background Technique

[0002] In the process of oil resource exploitation, the application of downhole tractors is crucial for the operation of deep wells, ultra-deep wells and horizontal wells. With the progress of oil exploitation technology and the diversification of well types, the traditional operation mode relying on self-weight and winch recovery can no longer meet the requirements. Therefore, downhole tractors came into being. It can effectively transport the operation equipment to the designated formation position, complete the operation task and help the equipment to recover.

[0003] Especially in the context of the development of coiled tubing technology, the advantages of downhole tractors are more prominent, and their usage rate has increased significantly. At present, downhole tractors mainly adopt electro-hydraulic drive, and their types include wheel type, gripping arm type, crawler type and telescopic type, etc. Among them, the telescopic tractor has become the current mainstream choice with its characteristics of stable transmission and large traction force.

[0004] For the coiled tubing running operation of ultra-deep wells and horizontal wells, the crawler type tractor has been eliminated due to insufficient traction force; although the wheel type tractor works stably, its traction force is limited; the gripping arm type tractor may cause damage to the wellbore and itself, and cannot work effectively in well sections with a large inclination. In contrast, the telescopic tractor has a simple structure, is safe and reliable, and can meet the needs of pulling coiled tubing in ultra-deep wells and horizontal wells.

[0005] There are mainly two common structures of telescopic tractors: link type and spring leaf type. The link type has a simple structure and high reliability, but poor adaptability, and there are dead points, which may affect downhole operations. The spring leaf type structure has the advantages of good flexibility and self-adaptability, but cannot meet the requirements of large traction force.

[0006] Therefore, in order to overcome the limitations of the existing tractors, we propose a symmetric downhole coiled tubing tractor. Content of the Utility Model

[0007] The purpose of the utility model is to solve the disadvantages such as limitations in use in the prior art, and to propose a symmetric downhole coiled tubing tractor.

[0008] In order to achieve the above purpose, the utility model adopts the following technical scheme:

[0009] Design a symmetric downhole coiled tubing tractor, including:

[0010] A control unit sleeved outside the central pipe;

[0011] and two peristaltic units symmetrically distributed on both sides of the control unit and connected to the outside of the central tube;

[0012] wherein the peristaltic unit includes a centralizer, a expanding brake device and a tensioning device, and the tensioning device is used to drive the expanding brake device to act;

[0013] It further includes a traction device for driving the central tube to move.

[0014] Furthermore, two expanding brake devices are provided in each peristaltic unit, and the tensioning directions of the two expanding brake devices are perpendicular. The two expanding brake devices are symmetrically distributed on both sides of the tensioning device, and the two expanding brake devices are controlled to act by the tensioning device.

[0015] Furthermore, the expanding brake device includes a traction block and a tensioning block sleeved on the outside of the central tube;

[0016] At least two connecting rod assemblies and at least two elastic members are arranged between the traction block and the tensioning block, and at least two of the connecting rod assemblies are used to abut against the inner wall of the oil well.

[0017] Furthermore, the connecting rod assembly includes a first connecting rod pinned to the traction block and a second connecting rod pinned to the tensioning block, and a central connecting rod is pinned between the first connecting rod and the second connecting rod;

[0018] wherein, the elastic member is located below the first connecting rod, the second connecting rod and the central connecting rod.

[0019] Furthermore, a rotating groove is formed on the end face of the central connecting rod, and a locking cam is rotatably connected in the rotating groove.

[0020] Furthermore, the tensioning device includes a tensioning cylinder body sleeved on the outside of the central tube, and a base is fixedly installed in the middle of the inner side of the tensioning cylinder body. Hydraulic cylinders are connected to both sides of the base, and the hydraulic cylinders on both sides are respectively fixed to the two tensioning blocks on both sides.

[0021] Furthermore, the traction device is arranged outside the expanding brake device far from the control unit;

[0022] wherein, the traction device includes a traction cylinder body, a piston is slidably connected in the traction cylinder body, the piston is fixedly connected to the central tube, one end of the traction cylinder body is connected to the centralizer, the other end is connected to the traction block, and sealing rings are arranged at the joints of the traction cylinder body with the centralizer and the traction block.

[0023] Further, two centering devices are provided in each peristaltic unit, and the two centering devices are circumferentially misaligned. The two centering devices are respectively arranged on one side of the control unit and one side of the traction device.

[0024] Further, the centering device includes two sliding seats, and a plurality of elastic sheets are scattered between the two sliding seats.

[0025] Further, two fixed hydraulic cylinders are symmetrically installed inside the traction block. The two fixed hydraulic cylinders are used to clamp and fix the central pipe. A channel for laying hydraulic pipelines is opened on the outer side of the central pipe, and a connector for connecting an oil pipe is fixedly installed at the end of the central pipe.

[0026] A symmetrical downhole coiled tubing tractor proposed by the present utility model has the following beneficial effects: The symmetrical downhole coiled tubing tractor has a simple design, high reliability, and good practicability. It has a powerful traction force and can achieve continuous operation, effectively solving the problem of insufficient traction force when placing coiled tubing in deep wells and ultra-deep well environments. At the same time, the device can apply a certain bit pressure to facilitate the retrieval of coiled tubing. When retrieving the coiled tubing, the control unit outputs the opposite action timing to cooperate with the retrieval operation of the tubing. The device is suitable for the traction operation of coiled tubing in deep wells and ultra-deep well environments. Description of the Drawings

[0027] Figure 1 is a structural schematic diagram of the present utility model;

[0028] Figure 2 is an exploded view of the expansion brake device of the present utility model;

[0029] Figure 3 is a sectional view of the expansion brake device of the present utility model;

[0030] Figure 4 is a structural schematic diagram of the tensioning device of the present utility model;

[0031] Figure 5 is a structural schematic diagram of the traction device of the present utility model;

[0032] Figure 6 is a structural schematic diagram of the centering device of the present utility model;

[0033] Figure 7 is a schematic diagram of the action timing of the overall device of the present utility model.

[0034] In the figure: 1. Central tube; 11. Channel; 12. Connector; 2. Control unit; 3. Peristaltic unit; 4. Centralizer; 41. Slide; 42. Elastic sheet; 5. Expanding brake device; 51. Traction block; 52. Tightening block; 53. Elastic member; 54. First connecting rod; 55. Second connecting rod; 56. Central connecting rod; 57. Locking cam; 58. Fixed hydraulic cylinder; 6. Tightening device; 61. Tightening cylinder body; 62. Base; 63. Hydraulic cylinder; 64. Cylinder head; 7. Traction device; 71. Traction cylinder body; 72. Piston; 73. Sealing ring. Detailed implementation manners

[0035] 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.

[0036] Referring to Figures 1-7 As an embodiment of the present invention, it discloses a symmetric downhole coiled tubing tractor, which includes a control unit 2 sleeved outside the central tube 1. The control unit 2 serves as the power source and control center of the overall tractor, and specifically includes a controller, an oil pump, and an oil tank. The controller controls the input and output of hydraulic oil to realize the action control of each hydraulic component. The specific hydraulic control principle is the prior art and will not be elaborated here;

[0037] And two peristaltic units 3 symmetrically distributed on both sides of the control unit 2 and connected to the outside of the central tube 1;

[0038] Wherein the peristaltic unit 3 includes a centralizer 4, an expanding brake device 5, and a tightening device 6. The tightening device 6 is used to drive the expanding brake device 5 to act;

[0039] It further includes a traction device 7 for driving the central tube 1 to move.

[0040] Referring to Figure 1 , in some embodiments, two expanding brake devices 5 are provided in each peristaltic unit 3 of the present invention, and the tightening directions of the two expanding brake devices 5 are perpendicular. Through tightening in two directions, the stability of the entire device after tightening in the oil well is ensured. Of course, those skilled in the art can also change the number of the above-mentioned expanding brake devices 5 according to actual needs, which are all included in the protection scope of the present invention. The two expanding brake devices 5 are symmetrically distributed on both sides of the tightening device 6, and the tightening device 6 controls the actions of the two expanding brake devices 5.

[0041] Referring to Figure 2 , 3, on the basis of the above embodiments, the expansion brake device 5 includes a traction block 51 and a tensioning block 52 sleeved outside the central tube 1, and both the traction block 51 and the tensioning block 52 are slidably connected to the central tube 1;

[0042] At least two link assemblies and at least two elastic members 53 are provided between the traction block 51 and the tensioning block 52. At least two of the link assemblies are used to abut against the inner wall of the oil well. In a further embodiment, the elastic member 53 in the present invention is provided as a spring piece, and both ends of the spring piece are fixed on the tensioning block 52 and the traction block 51. The spring piece can prevent the link assembly from generating a dead point position and prevent the rod from being locked, and can contribute to the recovery of the expansion brake and provide a certain thrust to the middle of the link.

[0043] Refer to Figure 2 , 3 , specifically, the link assembly in the present invention includes a first link 54 pin-connected to the traction block 51 and a second link 55 pin-connected to the tensioning block 52, and a central link 56 is pin-connected between the first link 54 and the second link 55;

[0044] In the present invention, between the first link 54 and the traction block 51, between the tensioning block 52 and the second link 55, and between the central link 56 and the first link 54 and the second link 55, a bolt-nut assembly is used for rotational cooperation. That is, after the bolt and nut are fixed, the corresponding rod rotates outside the screw to achieve the rotational ability. Secondly, the cooperation method of the bolt-nut assembly can also achieve convenient disassembly and assembly to improve the convenience of maintenance and installation;

[0045] Among them, the elastic member 53 is located below the first link 54, the second link 55, and the central link 56.

[0046] That is to say, in the present invention, the link assembly is used to abut against the inner wall of the oil well to complete the position fixation. The link assembly has the advantages of simple structure, high reliability, and easy replacement; the spring piece has the advantages of good self-adaptability and easy recovery. The combination of the two enables the entire expansion brake device 5 to have the advantages of both, prevents the situation of the link assembly generating a dead point position and the situation of the spring piece having insufficient elastic force, and in the tensioned state, the central link 56 receives the elastic force from the spring piece, making the force on the central link 56 more uniform.

[0047] Refer to Figure 2 , 3, in a preferred embodiment, a rotation groove is provided on the end face of the central connecting rod 56 of the present utility model. A locking cam 57 is rotatably connected in the rotation groove. There are two locking cams 57 above the central connecting rod 56. After the tensioning device is tensioned, it can effectively prevent the occurrence of slipping, improving the efficiency of the tractor. Specifically, in this embodiment, two locking cams 57 are rotatably provided on the outer side of each central connecting rod 56. The two locking cams are distributed on both sides of the center of the central connecting rod 56, which can prevent the occurrence of slipping after the expansion brake is locked. And two force application points on the well wall are added.

[0048] Refer to Figure 3 , in a further embodiment, the locking cam 57 of the present utility model can also be rotatably connected in the rotation groove by a torsion spring. The two ends of the torsion spring are respectively connected to the locking cam 57 and the rotation groove. Two magnets are installed at the upper end of the elastic member 53. Magnets are also embedded on the inclined surface of the locking cam 57. The two magnets are magnetically adsorbed. In the initial state, the two magnets attract each other, keeping the locking cam 57 in the rotation groove. When moving, since the central connecting rod 56 moves horizontally and the elastic member 53 will bend at the same time, the distance between the relative magnets will become larger. When moving further and the magnetism is separated, under the action of the torsion spring, the locking cam 57 will have an outward rotational force. Therefore, it can be ensured that the locking cam 57 always maintains an outward rotational drive during the tensioning process, improving the clamping ability with the well wall.

[0049] Refer to Figure 4 , in some embodiments, the tensioning device 6 of the present utility model includes a tensioning cylinder body 61 sleeved outside the central pipe 1. A base 62 is fixedly installed in the middle of the inner side of the tensioning cylinder body 61. Hydraulic cylinders 63 are connected to both sides of the base 62. In a further embodiment, two hydraulic cylinders 63 are pin-connected to both sides of the base 62. At the same time, cylinder heads 64 are fastened to both ends of the tensioning cylinder body 61 by bolts. The shaft ends of the hydraulic cylinders 63 pass through the cylinder heads 64. The two hydraulic cylinders 63 on both sides are respectively fixed to the two tensioning blocks 52 on both sides.

[0050] Specifically, the two hydraulic cylinders 63 on both sides are used to drive the two tensioning blocks 52 on both sides to move, so as to realize the deformation drive of the connecting rod assembly and make it reach the purpose of tensioning on the inner wall of the oil well. The tensioning block 52 realizes the mechanical synchronization of the single-side hydraulic cylinder. And during the opening stage of the expansion brake, the two hydraulic cylinders on both sides do not need to work completely synchronously. Before the end of the stage action timing, it can be fully extended to complete the opening of the expansion brake.

[0051] Refer to Figure 5 , further, in this embodiment, the traction device 7 is arranged outside the expansion brake device 5 away from the control unit 2;

[0052] Among them, the traction device 7 includes a traction cylinder block 71, in which a piston 72 is slidably connected. The piston 72 is fixedly connected to the central tube 1. One end of the traction cylinder block 71 is connected to the centralizer 4, and the other end is connected to the traction block 51. Sealing rings 73 are provided at the joints of the traction cylinder block 71 with the centralizer 4 and the traction block 51. Specifically, the ends of the centralizer 4 and the traction block 51 are respectively inserted into both ends of the traction cylinder block 71 and fastened and locked by bolts. Two sealing rings 73 are provided, which are respectively used to seal the circumferences and contact planes of the steps of the centralizer 4 and the traction block 51 to achieve better sealing performance. Of course, a sealing ring 73 should also be sleeved outside the piston 72 of the present invention to ensure the sealing stability of the hydraulic drive;

[0053] That is, as the piston 72 moves, it drives the central tube 1 to move. As the reciprocating motion occurs, the tractor continuously pulls the central tube 1 forward to complete the traction work of the coiled tubing.

[0054] Refer to Figure 1 , in addition, two centralizers 4 are provided in each peristaltic unit 3 of the present invention. The two centralizers 4 are circumferentially misaligned, and the two centralizers 4 are respectively arranged on one side of the control unit 2 and one side of the traction device 7.

[0055] Refer to Figure 6 , more specifically, the centralizer 4 of the present invention includes two sliding seats 41, and a plurality of elastic sheets 42 are scattered between the two sliding seats 41. The elastic sheets 42 are also set as spring sheets, and four spring sheets are distributed circumferentially on each centralizer 4. The spring sheets can effectively support the overall structure and can also adapt to the change of the pipe diameter. For complex downhole working conditions and deformed wellbores, it has stronger adaptability; the overall structure is equipped with four centralizers 4 evenly inserted between various structures, making the structure clearer and keeping the tractor always in the central position, reducing the wear of other structures and extending the service life of each component.

[0056] Refer to Figure 3It should be further explained that two fixed hydraulic cylinders 58 are symmetrically installed inside the traction block 51 in the utility model. The two fixed hydraulic cylinders 58 are used to clamp and fix the center pipe 1. The design purpose of using the fixed hydraulic cylinders 58 is: when the gate expansion device 5 is in the process of tightening, in order to avoid the traction blocks 51 on both sides from generating a directional extrusion reverse thrust, the center pipe 1 is clamped by the fixed hydraulic cylinders 58 in the utility model so that the traction block 51 is kept in a fixed position during the gate expansion process, so as to ensure that the gate expansion action can be carried out quickly and stably, and to avoid the reverse push movement of other parts during the gate expansion process. Of course, after the gate expansion is completed, the fixed hydraulic cylinders 58 are separated from the clamping of the center pipe 1 to ensure that the subsequent traction device 7 can stably pull and move the center pipe 1;

[0057] Reference Figure 5 In addition, a groove 11 for laying hydraulic pipelines is provided on the outer side of the central tube 1 in the utility model, and a connector 12 for connecting an oil pipe is fixedly installed at the end of the central tube 1.

[0058] By burying hydraulic pipelines on the outside of the central tube 1 and controlling the corresponding oil circuit switches through the control unit 2, the hydraulic oil is delivered to the fixed hydraulic cylinder 58, the tensioning device 6 and the traction device 7 to provide power for the movement of each hydraulic device. This wiring method improves the convenience of wiring and the overall consistency. In addition, the method of connecting the hydraulic pipelines to the hydraulic devices is only a conventional means for technicians in the relevant field, and will not be elaborated here.

[0059] The tractor adopts four groups of orthogonally arranged expansion devices 5. Each group of devices is interconnected by tensioning devices 6 and evenly distributed on both sides of the control unit 2. The control unit 2 is responsible for regulating the opening and closing actions of the expansion devices 5 and cooperates with the two groups of symmetrically configured traction devices 7 to jointly complete the directional traction of the coiled tubing.

[0060] Reference Figure 7 During the operation, when the right expansion device 5 is opened by the hydraulic cylinder 63, the connecting rod assembly is in close contact with the well wall, and at the same time, the left expansion device 5 is retracted by the hydraulic cylinder 63, and the piston 72 in the right traction cylinder 71 pulls the central pipe 1 to the left, driving the entire tractor and the coiled tubing to move to the left;

[0061] Subsequently, the left gate expansion device 5 is opened by the action of the hydraulic cylinder 63, and the right gate expansion device 5 is retracted. The piston 72 in the left traction cylinder 71 continues to pull the central tube 1 to the left, thereby realizing continuous leftward movement of the coiled tubing. The right gate expansion device 5 is opened again, and the left gate expansion device 5 is retracted, completing an action cycle. By continuously repeating this action cycle, the coiled tubing can be continuously pulled to the specified position.

[0062] In addition, during the opening stage of the expansion brake, the piston rod of the hydraulic cylinder 63 extends outwards, driving the connecting rod assembly to slowly unfold. The elastic member 53 plays a role in adjusting the mechanism posture and providing support during this process. Its elastic force ensures that the center of the connecting rod is evenly stressed, effectively avoiding the occurrence of dead point phenomena. During the locking stage of the expansion brake during traction, the expansion brake is tightly fixed to the wellbore wall. The piston 72 works under the command of the control unit 2, pushing the central pipe 1 to move leftward. At this time, the locking cam 57 comes into play, and the change in its radial dimension ensures that the tensioning device firmly locks the wellbore wall, preventing the expansion brake device from sliding.

[0063] During the retraction stage of the expansion brake, the piston rod of the hydraulic cylinder 63 contracts, and the elastic member 53 returns to its initial state and provides appropriate thrust to facilitate the effective retraction of the expansion brake device 5 and the tensioning device 6.

[0064] This symmetric downhole coiled tubing tractor is designed with simplicity, high reliability, and good practicability. It has a powerful traction force and can achieve continuous operation, effectively solving the problem of insufficient traction force of existing tractors when placing coiled tubing in deep well and ultra-deep well environments. At the same time, this device can apply a certain bit weight to facilitate the retrieval of coiled tubing. When retrieving the coiled tubing, the control unit 2 outputs the opposite action sequence to cooperate with the tubing retrieval operation. This device is suitable for the traction operation of coiled tubing in deep well and ultra-deep well environments.

[0065] The above is only the preferred specific embodiment of the present utility model, but the protection scope of the present utility model is not limited thereto. Any person skilled in the art within the technical scope disclosed by the present utility model, according to the technical solution of the present utility model and its inventive concept, makes equivalent substitutions or changes, and all should be covered within the protection scope of the present utility model.

Claims

1. A symmetrical downhole coiled tubing tractor, characterized in that: include: A control unit (2) sleeved on the outside of the central tube (1); and two peristaltic units (3) symmetrically distributed on both sides of the control unit (2) and connected to the outside of the central tube (1); The peristaltic unit (3) comprises a centralizer (4), a gate expansion device (5) and a tensioning device (6), wherein the tensioning device (6) is used to drive the gate expansion device (5) to operate; It also comprises a traction device (7) for driving the central pipe (1) to move.

2. A symmetrical downhole coiled tubing tractor according to claim 1, characterized in that: Two gate expansion devices (5) are provided in each of the peristaltic units (3), and the tensioning directions of the two gate expansion devices (5) are perpendicular. The two gate expansion devices (5) are symmetrically distributed on both sides of the tensioning device (6), and the movements of the two gate expansion devices (5) are controlled by the tensioning device (6).

3. A symmetrical downhole coiled tubing tractor according to claim 2, characterized in that: The expansion device (5) comprises a traction block (51) and a tension block (52) which are sleeved on the outside of the central tube (1); At least two connecting rod assemblies and at least two elastic members (53) are arranged between the traction block (51) and the tensioning block (52), and at least two of the connecting rod assemblies are used to abut against the inner wall of the oil well.

4. A symmetrical downhole coiled tubing tractor according to claim 3, characterized in that: The connecting rod assembly comprises a first connecting rod (54) pinned to the traction block (51), and a second connecting rod (55) pinned to the tensioning block (52), and a central connecting rod (56) pinned between the first connecting rod (54) and the second connecting rod (55); Wherein, the elastic member (53) is located below the first connecting rod (54), the second connecting rod (55) and the central connecting rod (56).

5. A symmetrical downhole coiled tubing tractor according to claim 4, characterized in that: A rotation groove is provided on the end surface of the central connecting rod (56), and a locking cam (57) is rotatably connected in the rotation groove.

6. The symmetrical downhole coiled tubing tractor according to claim 3, characterized in that: The tensioning device (6) comprises a tensioning cylinder body (61) sleeved on the outside of the central tube (1), a base (62) being fixedly mounted in the middle of the inner side of the tensioning cylinder body (61), wherein both sides of the base (62) are connected to hydraulic cylinders (63), and the hydraulic cylinders (63) on both sides are respectively fixed to two tensioning blocks (52) on both sides.

7. The symmetrical downhole coiled tubing tractor according to claim 3, characterized in that: The traction device (7) is arranged outside the expansion device (5) away from the control unit (2); The traction device (7) comprises a traction cylinder (71), a piston (72) is slidably connected in the traction cylinder (71), the piston (72) is fixedly connected to the center pipe (1), one end of the traction cylinder (71) is connected to the centralizer (4), and the other end is connected to the traction block (51), and sealing rings (73) are provided at the connection between the traction cylinder (71), the centralizer (4) and the traction block (51).

8. The symmetrical downhole coiled tubing tractor according to claim 1, characterized in that: Two centralizers (4) are provided in each of the peristaltic units (3), the two centralizers (4) are circumferentially staggered, and the two centralizers (4) are respectively provided on one side of the control unit (2) and one side of the traction device (7).

9. A symmetrical downhole coiled tubing tractor according to claim 8, characterized in that: The centralizer (4) comprises two slide seats (41), and a plurality of elastic sheets (42) are scattered between the two slide seats (41).

10. A symmetrical downhole coiled tubing tractor according to any one of claims 3 to 7, characterized in that: Two fixed hydraulic cylinders (58) are symmetrically installed inside the traction block (51). The two fixed hydraulic cylinders (58) are used to clamp and fix the central pipe (1). A groove (11) for laying hydraulic pipelines is opened on the outside of the central pipe (1). A connector (12) for connecting an oil pipe is also fixedly installed at the end of the central pipe (1).

Images