A split-type oil drilling crawler

Abstract

This invention relates to the field of pipeline crawler technology, and more particularly to a split-type oil drilling crawler. The crawler includes at least two crawling units, with adjacent crawling units connected in series along the axial direction. Each crawling unit includes a housing, a crawling wheel assembly, and an opening / closing drive mechanism. The housing contains independent high-pressure and low-pressure oil circuits. The opening / closing drive mechanism includes a cylinder and a piston shaft. The cylinder has a high-pressure chamber connected to the high-pressure oil circuit and a low-pressure chamber connected to the low-pressure oil circuit. The piston shaft is mounted inside the cylinder and is drively connected to the crawling wheel assembly to drive the crawling wheel assembly to retract or open. The low-pressure oil circuits of adjacent crawling units are connected. This invention effectively solves the technical problems of short axial support span and poor stability in existing single-section crawlers, and the inability to independently control each wheel assembly and the complex structure of multi-section series crawlers.

Description

Technical Field

[0001] This invention relates to the field of pipeline crawler technology, and more particularly to a split-type oil drilling crawler. Background Technology

[0002] The oil drilling crawler is a specialized downhole power delivery tool for oil and gas fields, integrating mechanical, electrical, and hydraulic systems. It is suitable for operations in complex well structures such as highly deviated wells and horizontal wells. During operation, the oil drilling crawler relies on its own drive mechanism to adhere closely to the inner wall of the wellbore, generating continuous and stable traction force. It can carry downhole testing instruments or working tools to complete the delivery, positioning, and related construction operations within the target well section. After the operation is completed, the oil drilling crawler can be retrieved to the surface via cable or coiled tubing.

[0003] Oil drilling crawlers typically include a controller, a drive motor, and crawling wheels. The controller controls the drive motor to move the crawling wheels along the pipeline. For example, patent application CN228129010A discloses a support wheel type pipeline crawler based on a three-axis differential. This crawler includes a controller, a crawling drive motor, and three independent differentials. After the controller controls the crawling drive motor to rotate, the power is simultaneously distributed to the three differentials via a transfer case. Each differential drives a set of chain drive mechanisms distributed circumferentially at 120°. Each set of chain drives the front and rear crawling wheels. At the same time, the rear end of the crawler is equipped with an electric push rod and a sliding sleeve. The sliding sleeve is connected to the three sets of wheel frames through a gas spring and a connecting rod. The controller controls the extension and retraction of the electric push rod based on the feedback signal from the pressure sensor, so that the three sets of crawling wheels open or close synchronously, thereby adapting to changes in pipe diameter and enabling stable movement in bends and obstructed pipelines.

[0004] However, the crawler has the following problems in actual use: The crawler is a single-section rigid structure with a short axial support span. When working in a large-diameter well, the front and rear support points are too concentrated, which can only form an approximate single-point concentrated support. This results in insufficient overall anti-torsion and anti-sway torque, making it difficult to effectively suppress the circumferential rotation and lateral sway of the machine body, and the stability is poor.

[0005] To address the core issues of short axial support span and poor stability, the industry's conventional approach is to design the crawler as a rigid structure with two or more sections connected in series, thereby increasing the overall support stability by extending the axial support span. However, the crawler described above employs a crawler wheel opening and closing mechanism with an electric push rod and a sliding sleeve at the rear. The sliding sleeve is connected to three sets of wheel frames via a gas spring and connecting rod. The controller controls the extension and retraction of the electric push rod based on pressure sensor feedback, driving the three sets of crawler wheels to open and close synchronously. When this crawler wheel opening and closing mechanism is applied to a multi-section series rigid structure, if a single opening and closing mechanism is used to centrally drive all the crawler wheel groups of the multi-section unit, a long push rod and linkage mechanism that runs through the multi-section body are required. This results in an excessively long transmission chain, severely delayed response, and high power loss. Furthermore, it is impossible to achieve independent and precise control of the opening and closing actions of each crawler wheel according to the differences in working conditions of the well sections where the preceding and following sections are located, affecting the overall movement of the crawler. If each series unit is equipped with an independent opening and closing mechanism, the number of parts and electrical control circuits will increase exponentially, increasing structural complexity. It is impossible to achieve a reasonable arrangement within the limited radial space of the oil and gas field wellbore, and it will also lead to an increase in failure points and a further decrease in operational reliability. Summary of the Invention

[0006] This invention provides a split-type oil drilling crawler to solve the technical problems of short axial support span and poor stability in existing single-section crawlers, and the inability to independently control each section wheel group and complex structure in multi-section serial crawlers.

[0007] To solve the above problems, the split-type oil drilling crawler provided by the present invention adopts the following technical solution: A split-type oil drilling crawler includes at least two crawling units, with two adjacent crawling units connected in series along the axial direction; Each of the crawling units includes a housing, a set of crawling wheels, and an opening and closing drive mechanism; The housing is provided with independent high-pressure oil circuits and low-pressure oil circuits. The opening and closing drive mechanism includes a cylinder and a piston shaft. The cylinder has a high-pressure chamber connected to the high-pressure oil circuit and a low-pressure chamber connected to the low-pressure oil circuit. The piston shaft is installed in the cylinder and is connected to the crawling wheel assembly for driving the crawling wheel assembly to retract or open. The low-pressure oil circuits of two adjacent crawling units are connected.

[0008] The beneficial effects of the split-type oil drilling crawler provided by this invention are: 1. By setting at least two independent crawling units, and fixing adjacent crawling units in series along the axial direction, the crawler as a whole forms a long-span support structure extending along the shaft axial direction. The crawling wheel sets of multiple crawling units are separated from each other axially and supported sequentially on the inner wall of the shaft, forming multi-point distributed support. This increases the overall axial support span of the crawler, thereby improving the overall anti-torsional moment and anti-sway moment, structurally suppressing the rotation and sway of the machine body, and improving operational stability.

[0009] 2. Each crawling unit is equipped with an independent opening and closing drive mechanism, which can independently adjust the opening degree of the crawling wheel assembly according to the inner diameter of its respective pipe section, avoiding swaying induced by the wheel assembly separating from the wall due to local pipe diameter changes. Simultaneously, when encountering areas where the casing inner diameter decreases or at joint clamps, the entire oil drilling crawler and its carried instruments can pass smoothly without getting stuck. The high-pressure oil circuits of each unit are independent, while the low-pressure oil circuits are interconnected. By supplying oil to the high-pressure chambers of each crawling unit, the piston shaft is driven to move the crawling wheel assembly to retract or open. During actual operation, even if a crawling unit temporarily enters a pipe section with a larger / smaller diameter, other units can still maintain reliable wall support, ensuring that the entire machine always has multi-point, distributed radial support force, thereby effectively suppressing the circumferential rotation and lateral sway of the machine body.

[0010] 3. The low-pressure oil circuits of two adjacent crawling units are connected, so that the low-pressure circuits of multiple crawling units can be connected and unified. Without affecting the independent control of the high-pressure oil circuits of each crawling unit, the overall hydraulic pipeline layout can be simplified, the number of pipeline joints can be reduced, the risk of downhole leakage can be reduced, and the long-span series structure can achieve compact and reliable hydraulic drive in a limited space, thereby stably and continuously solving the problems of short axial support and poor stability.

[0011] In summary, this invention effectively solves the technical problems of short axial support span and poor stability in single-section crawlers, and the inability to independently control each wheel group and complex structure in the opening and closing structure of multi-section tandem crawlers in the prior art. At the same time, it solves the problem that conventional crawlers cannot crawl in variable diameter sleeves.

[0012] Furthermore, the low-pressure chamber includes a first low-pressure chamber and a second low-pressure chamber, which are located on both sides of the high-pressure chamber.

[0013] Beneficial effects: By setting up a first low-pressure chamber and a second low-pressure chamber, and placing them on opposite sides of the high-pressure chamber, the piston shaft can withstand symmetrical and balanced hydraulic pressure and buffering force during axial movement. This effectively avoids radial load imbalance, jamming, and uneven wear caused by uneven force on one side of the piston shaft, improving the coaxiality and stability of the piston shaft movement. Simultaneously, the two low-pressure chambers provide stable pressure buffering and oil return channels at different stroke stages of the piston shaft's extension and retraction, making the opening and closing actions of the crawler wheel assembly more responsive and smoother, thereby improving the crawler's attitude stability and operational reliability during downhole operations.

[0014] Furthermore, oil ports are provided on the side walls of both the first low-pressure chamber and the second low-pressure chamber, and the oil ports are connected to the low-pressure oil circuit.

[0015] Furthermore, the cylinder body is provided with a partition, the piston shaft passes through the partition and can slide relative to the partition; one end of the piston shaft is provided with a pressure-bearing section, and the pressure-bearing section and the partition form the high-pressure chamber; the side of the pressure-bearing section away from the partition forms the first low-pressure chamber between the end of the cylinder body, and the side of the partition away from the pressure-bearing section forms the second low-pressure chamber between the end of the cylinder body.

[0016] Beneficial effects: On the one hand, the high-pressure chamber is located between the first and second low-pressure chambers, ensuring that the axial thrust on the piston shaft under hydraulic drive comes from only one side of its pressure-bearing section (i.e., the high-pressure chamber side). The two low-pressure chambers are located outside the pressure-bearing section and outside the partition, respectively. This ensures that during the piston shaft's extension or retraction, the low-pressure chambers can respectively handle oil return and replenishment functions, avoiding back pressure fluctuations or cavitation caused by poor oil return on one side, thereby improving the response speed and control accuracy of the opening and closing drive mechanism. On the other hand, by passing the piston shaft through the partition, the partition provides support and guidance for the piston shaft's extension and retraction, reducing the deflection deformation caused by the piston shaft's excessive length-to-diameter ratio and improving motion smoothness.

[0017] Furthermore, the opening and closing drive mechanism also includes a mounting shaft passing through the piston shaft, on which a retraction elastic element and a pressurizing elastic element are mounted; the retraction elastic element is located at the end of the cylinder body near the retraction direction of the piston shaft, and is used to provide a restoring elastic force to the piston shaft to extend it; the pressurizing elastic element is located at the end of the cylinder body away from the retraction direction of the piston shaft, and is used to provide an auxiliary elastic force to retract the piston shaft.

[0018] Beneficial effects: On the one hand, by inserting an installation shaft through the piston shaft and correspondingly arranging retractable and pressurizing elastic elements on the installation shaft, a coaxial integrated layout of the bidirectional elastic elements and the piston shaft is achieved, compressing the radial dimension of the opening and closing drive mechanism and enabling it to adapt to the narrow installation space within the oil drilling wellbore. On the other hand, the retractable elastic element is located at one end of the piston shaft in the retraction direction, providing a restoring elastic force to extend it; the pressurizing elastic element is located at the opposite end, providing an auxiliary elastic force to retract it. When oil is supplied to the high-pressure chamber, the hydraulic thrust and the elastic force of the pressurizing elastic element are in opposite directions, overcoming the resistance of the retractable and pressurizing elastic elements, causing the piston shaft to retract quickly and driving the crawler wheel assembly to open; when the hydraulic pressure is released, the elastic force of the retractable elastic element acts alone (or is superimposed with the residual elastic force of the pressurizing elastic element), causing the piston shaft to extend smoothly and realizing the retraction of the crawler wheel assembly. The two elastic elements and the hydraulic thrust form a resultant force superposition and balance relationship, which not only reduces the required hydraulic pressure but also ensures a smooth force transition of the piston shaft in bidirectional movement, avoiding impact.

[0019] Furthermore, the stiffness of the pressurizing elastic element is greater than the stiffness of the retracting elastic element.

[0020] Beneficial effects: On the one hand, the main function of the pressurizing elastic element is to achieve the same axial force with a shorter piston shaft retraction stroke when supplying oil to the high-pressure chamber, thereby reducing the amount of oil drawn into the high-pressure chamber. Simultaneously, it assists the retracting elastic element in driving the piston shaft to extend. Since the retracting wheel assembly needs to overcome pipe wall resistance and internal friction, requiring a large driving force, a high-stiffness pressurizing elastic element ensures that it stores sufficient elastic potential energy during compression, thus releasing a large auxiliary thrust. On the other hand, the main function of the retracting elastic element is to provide a restoring force after hydraulic depressurization, causing the piston shaft to extend. The lower stiffness ensures that the energy stored in the retracting elastic element during piston shaft retraction is moderate, and the energy released after depressurization is not excessive, thus ensuring smooth and controllable opening / closing of the crawler wheel assembly.

[0021] Furthermore, the crawling wheel assembly includes two crawling wheels, both of which are connected to the piston shaft via a drive mechanism.

[0022] Furthermore, the piston shaft is connected to the two crawling wheels via a connecting assembly. The connecting assembly includes two connecting rods and two support arms. Each support arm is rotatably mounted on the housing at one end and connected to a crawling wheel at the other end. The two connecting rods correspond one-to-one with the two support arms. One end of the connecting rod is fixed to the piston shaft, and the other end is hinged to the corresponding support arm via a guide sliding mechanism. The axial movement of the piston shaft drives the support arm to rotate, thereby opening and closing the crawling wheel assembly.

[0023] Beneficial effects: The connecting assembly adopts a symmetrical arrangement of two connecting rods and two support arms, each corresponding to a crawler wheel. The two support arms are rotatably mounted on both sides of the housing, each connected to a crawler wheel. When the piston shaft moves axially, the two connecting rods synchronously push the corresponding support arms to swing around their rotation axis, thus causing the two crawler wheels to open or close symmetrically. This symmetrical drive method ensures that the crawler wheel assembly always moves synchronously around the crawler's axis during opening and closing, avoiding the uneven load or tilting that may occur with unilateral drive. This improves the uniformity of the crawler wheel assembly's contact with the pipe's inner wall and enhances the overall centering stability and torsional resistance of the crawler.

[0024] Furthermore, the guide sliding mechanism includes a slider and an arc-shaped groove. The slider is located at the end of the connecting rod away from the piston shaft, and the arc-shaped groove is formed on the support arm. The slider is slidably assembled in the arc-shaped groove.

[0025] Beneficial effects: The slider is located at the end of the connecting rod away from the piston shaft, and an arc-shaped groove is formed on the support arm. The slider is slidably mounted in the arc-shaped groove. When the piston shaft moves axially, the connecting rod pushes the slider to slide within the arc-shaped groove. Simultaneously, the slider applies pressure to the groove wall, driving the support arm to swing around its rotation axis. The slider can move along an arc-shaped trajectory within the groove, effectively compensating for motion trajectory deviations caused by the fixed length of the connecting rod and the changing rotation radius of the support arm, and avoiding additional bending moments or motion interference between the connecting rod and the support arm.

[0026] Furthermore, it also includes a controller and a detection unit. The controller is signal-connected to the detection unit and each of the crawling units. The detection unit is used to collect well working condition information and transmit it to the controller. The controller is used to control the actions of each of the crawling units according to the received well working condition information. Attached Figure Description

[0027] Figure 1 This is a schematic diagram of the application structure of the split-type oil drilling crawler provided by the present invention; Figure 2 for Figure 1 The left view; Figure 3 for Figure 2 Sectional view of AA in the middle; Figure 4 for Figure 3 A magnified view of a portion of point A in the middle; Figure 5 for Figure 3 A magnified view of a portion of point B in the middle; Figure 6 for Figure 2 Cross-sectional view of the middle section (BB); Figure 7 for Figure 6 A magnified view of a portion of point A in the middle; Figure 8 for Figure 6 A magnified view of a portion of point B in the middle.

[0028] Explanation of reference numerals in the attached figures: 1. Housing; 11. High-pressure oil circuit; 12. Low-pressure oil circuit; 2. Crawler wheel; 21. Walking drive motor; 3. Opening and closing drive mechanism; 31. Cylinder; 311. First low-pressure chamber; 312. Second low-pressure chamber; 313. High-pressure chamber; 314. Oil port; 315. Isolation; 316. Connecting oil circuit; 317. Solenoid valve; 32. Piston shaft; 321. Pressure bearing section; 33. Mounting shaft; 331. Mounting seat; 332. Connecting seat; 34. Retractable elastic element; 35. Pressurizing elastic element; 4. Connecting assembly; 41. Connecting rod; 42. Support arm; 5. Guide sliding mechanism; 51. Slider; 52. Arc-shaped slide groove; 6. Controller; 7. Detection unit; 8. Cable connector; 9. Pipeline; 10. Hydraulic drive motor; 101. Hydraulic pump; 102. Coupling; 20. Connecting joint; 30. Logging instrument. Detailed Implementation

[0029] The principles and spirit of the present invention will be explained in detail below with reference to several representative embodiments.

[0030] Embodiments of the split-type oil drilling crawler provided by the present invention: like Figures 1 to 8 As shown, the split-type oil drilling crawler includes a cable connector 8, a controller 6, a detection unit 7, and two crawling units connected in series along the axial direction, with each crawling unit having an identical structure. A pipe 9 is laid inside the oil well, and the split-type oil drilling crawler is located within the pipe 9 and can crawl along the pipe 9. In other embodiments, the number of crawling units can be three, four, etc., to meet practical application requirements.

[0031] like Figures 3 to 8 As shown, in this embodiment, the crawling unit includes a housing 1, a walking drive source, two sets of crawling wheels, and an opening / closing drive mechanism 3. The walking drive source is connected to the two sets of crawling wheels for driving them forward. The housing 1 contains independent high-pressure oil circuits 11 and 12. In this embodiment, the walking drive source is a walking drive motor 21.

[0032] like Figure 2 and Figure 7 As shown, in this embodiment, the opening and closing drive mechanism 3 includes a cylinder 31, a piston shaft 32, a mounting shaft 33, a retraction elastic element 34, and a pressure elastic element 35.

[0033] like Figure 4 , Figure 5 , 7 and Figure 8 As shown, in this embodiment, the cylinder body 31 has a high-pressure chamber 313 connected to the high-pressure oil circuit 11 and a low-pressure chamber connected to the low-pressure oil circuit 12. The piston shaft 32 is installed inside the cylinder body 31 and is connected to the crawler wheel 2 set for driving the crawler wheel 2 set to retract or open. In this embodiment, the cylinder body 31 is provided with a connecting oil circuit 316 connecting the high-pressure chamber 313 and the high-pressure oil circuit 11.

[0034] like Figure 4 and Figure 7 As shown, in this embodiment, the mounting shaft 33 passes through the piston shaft 32, and the retraction elastic element 34 and the pressurizing elastic element 35 are both sleeved on the mounting shaft 33. A mounting seat 331 is installed at the left end of the cylinder body 31, and the left end of the mounting shaft 33 is fixedly installed on the mounting seat 331. A connecting seat 332 is sleeved on its right end. The connecting seat 332 includes a first sleeve section, a second sleeve section, and a connecting section arranged sequentially from left to right. The outer diameter of the first sleeve section, the second sleeve section, and the connecting section increases sequentially. The first sleeve section is sleeved on the outer periphery of the mounting shaft 33 and passes through the right end of the piston shaft 32, and the second sleeve section is sleeved on the outer periphery of the mounting shaft 33.

[0035] like Figure 4 and Figure 7 As shown, in this embodiment, the retractable elastic member 34 is located on the left side of the piston shaft 32, with its two ends abutting against the left end face of the piston shaft 32 and the right end face of the mounting base 331, respectively, to provide a restoring elastic force to the piston shaft 32 to extend to the right; the pressurizing elastic member 35 is located on the right side of the piston shaft 32 and is sleeved on the second sleeve section, with its two ends abutting against the right end face of the piston shaft 32 and the left end face of the connecting section, respectively, to provide an auxiliary elastic force to the piston shaft 32 to extend to the right.

[0036] In this embodiment, both the retractable elastic element 34 and the compressive elastic element 35 are cylindrical helical springs, and the stiffness of the compressive elastic element 35 is greater than that of the retractable elastic element 34. In other embodiments, the retractable elastic element 34 is a disc spring assembly, and the compressive elastic element 35 is a rubber spring.

[0037] like Figure 4 and Figure 7 As shown, in this embodiment, the low-pressure chamber includes a first low-pressure chamber 311 and a second low-pressure chamber 312. The first low-pressure chamber 311 and the second low-pressure chamber 312 are located on both sides of the high-pressure chamber 313. Oil ports 314 are provided on the side walls of the first low-pressure chamber 311 and the second low-pressure chamber 312, and the oil ports 314 are connected to the low-pressure oil passage 12.

[0038] like Figure 4 and Figure 7As shown, in this embodiment, a partition 315 is provided inside the cylinder body 31, and the piston shaft 32 passes through the partition 315 and can slide relative to the partition 315. One end of the piston shaft 32 is provided with a pressure-bearing section 321. A high-pressure chamber 313 is formed between the right end face of the pressure-bearing section 321 and the partition 315. A first low-pressure chamber 311 is formed between the left end face of the pressure-bearing section 321 and the left end of the cylinder body 31. A second low-pressure chamber 312 is formed between the right end face of the partition 315 and the right end of the cylinder body 31.

[0039] like Figure 3 and Figure 6 As shown, in this embodiment, the crawling wheel group 2 includes two crawling wheels 2, which are connected to the piston shaft 32 via the connecting assembly 4.

[0040] like Figure 4 and Figure 5 As shown, in this embodiment, the connecting component 4 includes two connecting rods 41 and two support arms 42. Each support arm 42 is rotatably mounted on the housing 1 at one end and connected to a crawling wheel 2 at the other end. The two connecting rods 41 correspond one-to-one with the two support arms 42. The left end of the connecting rod 41 is fixed to the piston shaft 32 through the connecting seat 332, and its right end is hinged to the corresponding support arm 42 through the guide sliding mechanism 5. The axial movement of the piston shaft 32 drives the connecting rod 41 to move axially, thereby driving the support arm 42 to rotate, and finally realizing the opening or closing of the crawling wheel 2 set.

[0041] like Figure 5 As shown, in this embodiment, the guide sliding mechanism 5 includes a slider 51 and an arc-shaped groove 52. The slider 51 is located at the right end of the connecting rod 41, that is, the end away from the piston shaft 32. The arc-shaped groove 52 is opened on the support arm 42, and the slider 51 is slidably assembled in the arc-shaped groove 52.

[0042] In this embodiment, when the crawler wheels 2 are retracted, the center of each arc-shaped groove 52 is located on the side of the arc-shaped groove 52 facing the connecting rod 41. In other embodiments, when the crawler wheels 2 are retracted, the center of each arc-shaped groove 52 is located on the side of the arc-shaped groove 52 away from the connecting rod 41.

[0043] like Figure 3 and Figure 6 As shown, in this embodiment, the left end of the crawler is provided with a hydraulic drive motor 10 and a hydraulic pump 101. The hydraulic drive motor 10 and the hydraulic pump 101 are connected by a coupling 102 so that the hydraulic drive motor 10 drives the hydraulic pump 101 to rotate, pressurize the low-pressure oil into high-pressure oil, and deliver it to the high-pressure chamber 313 through the high-pressure oil circuit 11.

[0044] like Figure 7 and Figure 8As shown, in this embodiment, the low-pressure oil circuits 12 of two adjacent crawling units are connected, and the high-pressure oil circuits 11 of two adjacent crawling units are connected. In other embodiments, the low-pressure oil circuits 12 of two adjacent crawling units are connected, and the high-pressure oil circuits 11 of two adjacent units are independent of each other; each crawling unit is equipped with an independent hydraulic drive motor 10 and a hydraulic pump 101. The hydraulic pump 101 is connected to the low-pressure oil circuit 12 of the crawling unit. The hydraulic drive motor 10 drives the hydraulic pump 101 to rotate, drawing low-pressure oil from the low-pressure oil circuit 12, pressurizing it, and outputting high-pressure oil. The high-pressure oil enters the high-pressure chamber 313 through the connecting oil circuit 316.

[0045] like Figure 4 , Figure 7 and Figure 8 As shown, in this embodiment, each crawling unit is provided with a solenoid valve 317 at the left end of the connecting oil circuit 316, so as to control whether high-pressure oil is introduced into the high-pressure chamber 313 by the opening and closing of the solenoid valve 317.

[0046] like Figure 3 and Figure 6 As shown, in this embodiment, the controller 6 is located to the left of the left crawling unit, and the detection unit 7 is located to the right of the right crawling unit. The controller 6 is signal-connected to the detection unit 7 and each crawling unit. The detection unit 7 is used to collect working condition information such as the diameter of the pipe 9 in the well and vibration impact, and transmit it to the controller 6. The controller 6 is used to control the operation of the walking drive motor 21 according to the received working condition information in the pipe 9, so as to control the crawling wheel 2 to move, and to control the opening and closing of the solenoid valve 317, so as to control the opening or closing of the crawling wheel 2 group, thereby realizing the control of the action of each crawling unit. In this embodiment, the crawler moves from left to right or from right to left in the oil well.

[0047] like Figure 1 , Figure 3 and Figure 6 As shown, in this embodiment, the cable connector 8 is located on the left side of the controller 6 and is electrically connected to the controller 6; the right side of the detection unit 7 is provided with a connection connector 20, which is used to connect the logging instrument 30.

[0048] The working principle of the split-type oil drilling crawler provided by this invention is as follows: According to the pipeline 9 operating condition information collected by the detection unit 7, the controller 6 controls the rotation of the walking drive motor 21 of each crawling unit, driving the crawling wheels 2 to move along the well wall; at the same time, the controller 6 controls the opening and closing of the solenoid valve 317 at the left end of the high-pressure oil circuit 11 in each crawling unit.

[0049] When the solenoid valve 317 is opened, the hydraulic drive motor 10 drives the hydraulic pump 101 to generate high-pressure oil, which enters the high-pressure chamber 313 of the cylinder 31 through the high-pressure oil circuit 11. The high-pressure oil pushes the pressure-bearing section 321 on the piston shaft 32, overcoming the elastic force of the left retractable elastic element 34 and the right pressure-applying elastic element 35 with greater stiffness, causing the piston shaft 32 to retract to the left. The piston shaft 32 drives the slider 51 to move to the left along the arc-shaped slide groove 52 through the connecting rod 41, so as to drive the support arm 42 to swing outward, thereby causing the two crawler wheels 2 to open symmetrically to press against the well wall. When the solenoid valve 317 is closed and the high-pressure chamber 313 is depressurized, the elastic force of the left retractable elastic element 34 and the right pressure-applying elastic element 35 pushes the piston shaft 32 to extend to the right, and drives the slider 51 to move to the right along the arc-shaped slide groove 52 through the connecting rod 41, so as to drive the support arm 42 to swing inward, causing the crawler wheel 2 sets to retract. The low-pressure oil circuits 12 of each crawling unit are interconnected through the connecting oil circuits 316 in the connecting housing, and the high-pressure oil circuits 11 of each unit are also interconnected to ensure oil pressure balance. However, the solenoid valves 317 of each unit are independently turned on and off, thereby realizing independent opening and closing control of each unit wheel set.

[0050] Based on the above description in this specification, those skilled in the art will also understand that the following terms, such as "upper," "lower," "front," "back," "left," "right," "inner," and "outer," which indicate orientation or positional relationship, are based on the orientation or positional relationship shown in the accompanying drawings of this specification and should not be understood or interpreted as limiting the present invention.

[0051] In addition, in the description of this specification, "multiple" means at least two, such as two, three or more, etc., unless otherwise expressly and specifically defined.

Claims

1. A split-type oil drilling crawler, characterized in that, It includes at least two crawling units, with two adjacent crawling units connected in series along the axial direction; Each of the crawling units includes a housing, a set of crawling wheels, and an opening and closing drive mechanism; The housing is provided with independent high-pressure oil circuits and low-pressure oil circuits. The opening and closing drive mechanism includes a cylinder and a piston shaft. The cylinder has a high-pressure chamber connected to the high-pressure oil circuit and a low-pressure chamber connected to the low-pressure oil circuit. The piston shaft is installed in the cylinder and is connected to the crawling wheel assembly for driving the crawling wheel assembly to retract or open. The low-pressure oil circuits of two adjacent crawling units are connected.

2. The split-type oil drilling crawler according to claim 1, characterized in that, The low-pressure chamber includes a first low-pressure chamber and a second low-pressure chamber, which are located on both sides of the high-pressure chamber.

3. The split-type oil drilling crawler according to claim 2, characterized in that, Both the first low-pressure chamber and the second low-pressure chamber have oil ports on their side walls, and the oil ports are connected to the low-pressure oil circuit.

4. The split-type oil drilling crawler according to claim 2 or 3, characterized in that, The cylinder body is provided with a partition, and the piston shaft passes through the partition and can slide relative to the partition; one end of the piston shaft is provided with a pressure-bearing section, and the pressure-bearing section and the partition form the high-pressure chamber; the side of the pressure-bearing section away from the partition forms the first low-pressure chamber between the end of the cylinder body, and the side of the partition away from the pressure-bearing section forms the second low-pressure chamber between the end of the cylinder body.

5. The split-type oil drilling crawler according to any one of claims 1 to 3, characterized in that, The opening and closing drive mechanism further includes a mounting shaft passing through the piston shaft, on which a retraction elastic element and a pressurizing elastic element are mounted; the retraction elastic element is located at the end of the cylinder body near the retraction direction of the piston shaft, and is used to provide a restoring elastic force to the piston shaft to extend it; the pressurizing elastic element is located at the end of the cylinder body away from the retraction direction of the piston shaft, and is used to provide an auxiliary elastic force to retract the piston shaft.

6. The split-type oil drilling crawler according to claim 5, characterized in that, The stiffness of the pressurized elastic element is greater than the stiffness of the retracted elastic element.

7. The split-type oil drilling crawler according to any one of claims 1 to 3, characterized in that, The crawler wheel assembly includes two crawler wheels, both of which are connected to the piston shaft via a drive mechanism.

8. The split-type oil drilling crawler according to claim 7, characterized in that, The piston shaft is connected to the two crawling wheels via a connecting assembly. The connecting assembly includes two connecting rods and two support arms. Each support arm is rotatably mounted on the housing at one end and connected to a crawling wheel at the other end. The two connecting rods correspond one-to-one with the two support arms. One end of the connecting rod is fixed to the piston shaft, and the other end is hinged to the corresponding support arm through a guide sliding mechanism. The axial movement of the piston shaft drives the support arm to rotate, thereby opening and closing the crawling wheel assembly.

9. The split-type oil drilling crawler according to claim 8, characterized in that, The guide sliding mechanism includes a slider and an arc-shaped groove. The slider is located at the end of the connecting rod away from the piston shaft, and the arc-shaped groove is formed on the support arm. The slider is slidably assembled in the arc-shaped groove.

10. The split-type oil drilling crawler according to any one of claims 1 to 3, characterized in that, It also includes a controller and a detection unit. The controller is signal-connected to the detection unit and each of the crawling units. The detection unit is used to collect well working condition information and transmit it to the controller. The controller is used to control the actions of each of the crawling units according to the received well working condition information.

Images