Telescopic tube structure

Abstract

A telescopic tube structure, comprising: a step force balance module. The step force balance module comprises a balance outer tube assembly and a balance inner tube assembly capable of axially moving relative to the balance outer tube assembly; an outer protruding portion is provided on the outer circumference of the balance inner tube assembly; an inner protruding portion is provided on the inner circumference of the balance outer tube assembly; the balance inner tube assembly and the balance outer tube assembly define an outer chamber (6) located on the upper side of the outer protruding portion and an inner chamber (3) located between the outer protruding portion and the inner protruding portion; an outer pressure transmission hole (5) for enabling the outer chamber (6) to be communicated with the exterior of the balance outer tube assembly is formed in the balance outer tube assembly; and an inner pressure transmission hole (4) for enabling the inner chamber (3) to be communicated with the interior of the balance inner tube assembly is formed in the balance inner tube assembly. By means of the technical solution, the step force balance module uses an axial force generated by the pressure difference between the inner and outer chambers to counteract the step force, thereby effectively improving the stress distribution of a tubing string, and increasing a safety coefficient.

Description

Telescopic tube structure

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] This application claims the benefit of Chinese patent application 202311862397.0 filed on December 29, 2023, the contents of which are incorporated herein by reference. Technical Field

[0003] The present disclosure relates to the technical field of downhole tools in oil and gas fields, and in particular to a telescopic tube structure. Background Art

[0004] The integrity of oil and gas pipeline systems is essential for safe oil and gas production. During fracturing and production, pipelines in pipe strings equipped with packers can deform due to gravity, internal and external pressure, and temperature. Failure to release this deformation can lead to excessive stress within the string, potentially causing plastic deformation and rupture failure. Currently, field testing uses expansion joints to compensate for this deformation. However, conventional expansion joints create significant axial step forces on the sealing end under high pressure, severely impacting the string's load.

[0005] Summary of the Invention

[0006] A technical problem to be solved by the present disclosure is that the conventional telescopic tube structure is subjected to excessive step force.

[0007] To solve the above technical problems, an embodiment of the present disclosure provides a telescopic tube structure, which includes a step force balancing module, wherein the step force balancing module includes a balancing outer tube assembly and a balancing inner tube assembly that can move axially relative to the balancing outer tube assembly, an outer protrusion is provided on the outer periphery of the balancing inner tube assembly, and an inner protrusion is provided on the inner periphery of the balancing outer tube assembly, the balancing inner tube assembly and the balancing outer tube assembly form an outer chamber located on the upper side of the outer protrusion and an inner chamber located between the outer protrusion and the inner protrusion, the balancing outer tube assembly is provided with an external pressure transmission hole connected to the outer chamber and the outside of the balancing outer tube assembly, and the balancing inner tube assembly is provided with an internal pressure transmission hole connected to the inner chamber and the inside of the balancing inner tube assembly.

[0008] In some embodiments, the step force balancing module further includes an activation pin passing through the balancing outer tube assembly and partially inserted into the balancing inner tube assembly.

[0009] In some embodiments, the balancing inner tube assembly includes a balancing inner tube and a balancing inner tube joint connected to an upper end of the balancing inner tube, and the outer protrusion is provided on the balancing inner tube joint.

[0010] In some embodiments, a high-pressure seal located in the outer chamber is sleeved on the outer periphery of the balancing inner pipe joint.

[0011] In some embodiments, a balancing inner pipe sealing end head located at the lower side of the high-pressure seal is sleeved on the outer periphery of the balancing inner pipe joint.

[0012] In some embodiments, the balancing outer tube assembly includes a balancing outer tube, a balancing sealing tube connected to the lower end of the balancing outer tube, and a high-pressure sealing member provided on the inner circumferential surface of the balancing sealing tube.

[0013] In some embodiments, the balancing outer tube assembly includes a balancing outer tube joint partially inserted into the lower end of the balancing sealing tube, and the upper end of the balancing outer tube joint presses the high-pressure seal on the inner circumference of the balancing sealing tube.

[0014] In some embodiments, a guide sliding module is further included that is connected to the step force balancing module, and the guide sliding module includes a guide outer tube assembly that is connected to the balancing outer tube assembly and a guide inner tube assembly that is connected to the balancing inner tube assembly. The guide inner tube assembly and the guide outer tube assembly are key-grooved with each other to enable relative axial movement.

[0015] In some embodiments, the guide outer tube assembly includes a guide outer tube, a guide outer tube joint connected to the lower end of the guide outer tube, and a guide key provided on the inner circumference of the guide outer tube joint.

[0016] In some embodiments, the guide outer tube assembly further includes a positioning end head partially inserted into the lower end of the guide outer tube joint, the guide key is detachably provided on the inner circumference of the guide outer tube joint, and the positioning end head presses the lower end of the guide key.

[0017] In some embodiments, the guide inner tube assembly includes a guide inner tube, and a guide groove for accommodating the guide key is provided on the outer circumference of the guide inner tube.

[0018] In some embodiments, a high-pressure seal is provided on the outer periphery of the upper end of the guide inner tube.

[0019] In some embodiments, the guide inner tube assembly further includes a guide inner tube sealing end head partially sleeved on the upper end of the guide inner tube, and the guide inner tube sealing end head presses the high-pressure seal.

[0020] In some embodiments, an upper joint connected to the upper end of the guide outer tube assembly is further included.

[0021] In some embodiments, the device further includes a lower joint connected to the lower end of the balancing inner tube assembly.

[0022] Through the above technical solution, the step force balancing module uses the axial force generated by the pressure difference between the inner and outer chambers to offset the step force, effectively improving the stress state of the pipe string and increasing the safety factor. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] In order to more clearly illustrate the embodiments of the present disclosure or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are only some embodiments of the present disclosure. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0024] FIG1 is a partial cross-sectional view of a step force balancing module according to an embodiment of the present invention;

[0025] FIG2 is a partial cross-sectional view of the guide sliding module according to an embodiment of the present invention;

[0026] FIG3 is a partial cross-sectional view of the upper joint according to an embodiment of the present invention;

[0027] FIG4 is a partial cross-sectional view of the lower joint according to an embodiment of the present invention;

[0028] FIG5 is a cross-sectional view of the connection between the guide sliding module and the upper joint according to an embodiment of the present invention;

[0029] FIG6 is a cross-sectional view of the connection between the guide sliding module and the step force balancing module according to an embodiment of the present invention;

[0030] FIG7 is a cross-sectional view of the connection between two step force balancing modules according to an embodiment of the present invention;

[0031] FIG8 is a cross-sectional view of the connection between the step force balancing module and the lower joint according to an embodiment of the present invention;

[0032] 9 and 10 are force analysis diagrams of the telescopic tube of the prior art;

[0033] FIG11 and FIG12 are force analysis diagrams of the telescopic tube structure of this solution.

[0034] Description of reference numerals:

[0035] 1-Balancing outer tube, 2-Balancing inner tube, 3-Inner chamber, 4-Inner pressure transmission hole, 5-Outer pressure transmission hole, 6-Outer chamber, 7-Balancing inner tube joint, 8-Balancing inner tube sealing end, 9-Start pin, 10-High pressure seal, 11-Location pin, 12-Balancing outer tube joint, 13-Balancing sealing tube, 14-Guide outer tube, 15-Guide inner tube, 16-Guide outer tube joint, 17-Guide key, 18-Location end, 19-Guide groove, 20-Guide inner tube sealing end, 21-Upper joint, 22-Lower joint. DETAILED DESCRIPTION

[0036] The following embodiments of the present disclosure are further described in detail with reference to the accompanying drawings and examples. The detailed description of the following examples and the accompanying drawings are intended to illustrate the principles of the present disclosure, but are not intended to limit the scope of the present disclosure. The present disclosure can be implemented in many different forms and is not limited to the specific embodiments disclosed herein, but rather includes all technical solutions within the scope of the claims.

[0037] The present disclosure provides these embodiments in order to make this disclosure thorough and complete, and to fully convey the scope of the present disclosure to those skilled in the art. It should be noted that: unless otherwise specifically stated, the relative arrangement of parts and steps, the composition of materials, numerical expressions and numerical values ​​set forth in these embodiments should be interpreted as merely exemplary, and not as limiting.

[0038] It should be noted that, in the description of this disclosure, unless otherwise specified, "plurality" means greater than or equal to two; terms such as "upper," "lower," "left," "right," "inner," and "outer" indicating directions or positional relationships are intended solely to facilitate and simplify the description of this disclosure, and do not indicate or imply that the devices or elements referred to must have a specific orientation, be constructed, or operate in a specific orientation. Therefore, they should not be construed as limitations on this disclosure. When the absolute position of the object being described changes, the relative positional relationship may also change accordingly.

[0039] In addition, the terms "first," "second," and similar terms used in this disclosure do not denote any order, quantity, or importance, but are merely used to distinguish different parts. "Perpendicular" does not mean perpendicular in the strict sense, but rather means within the tolerance range. "Parallel" does not mean parallel in the strict sense, but rather means within the tolerance range. "Include" or "comprising" and similar terms mean that the elements preceding the term include the elements listed after the term, and do not exclude the possibility of also including other elements.

[0040] It should also be noted that, in the description of this disclosure, unless otherwise expressly specified or limited, the terms "installed," "connected," and "connected" should be understood in a broad sense. For example, they can refer to fixed connections, detachable connections, or integral connections; they can refer to direct connections or indirect connections through an intermediary. Those skilled in the art will understand the specific meanings of the above terms in this disclosure depending on the specific circumstances. When a specific device is described as being located between a first device and a second device, there may or may not be an intervening device between the specific device and the first or second device.

[0041] All terms used in this disclosure have the same meaning as understood by one of ordinary skill in the art to which this disclosure belongs, unless otherwise specifically defined. It should also be understood that terms defined in, for example, common dictionaries should be interpreted as having a meaning consistent with their meaning in the context of the relevant art, and should not be interpreted in an idealized or highly formal sense, unless explicitly defined as such herein.

[0042] Technologies, methods, and equipment known to ordinary technicians in the relevant art may not be discussed in detail, but where appropriate, the technologies, methods, and equipment should be considered part of the specification.

[0043] The present solution provides a telescopic tube structure, which includes a step force balancing module, wherein the step force balancing module includes a balancing outer tube assembly and a balancing inner tube assembly capable of axially moving relative to the balancing outer tube assembly, an outer protrusion is provided on the outer periphery of the balancing inner tube assembly, and an inner protrusion is provided on the inner periphery of the balancing outer tube assembly, the balancing inner tube assembly and the balancing outer tube assembly form an outer chamber 6 located on the upper side of the outer protrusion and an inner chamber 3 located between the outer protrusion and the inner protrusion, the balancing outer tube assembly is provided with an outer pressure transmission hole 5 connected to the outer chamber 6 and the outside of the balancing outer tube assembly, and the balancing inner tube assembly is provided with an inner pressure transmission hole 4 connected to the inner chamber 3 and the inside of the balancing inner tube assembly.

[0044] The step force balancing module is a part of the telescopic tube structure, which is roughly tubular and is mainly used to balance the step force borne by the telescopic tube structure as a whole.

[0045] Among them, the step force balancing module includes a balancing outer tube assembly and a balancing inner tube assembly arranged in the balancing outer tube assembly, an outer protrusion is formed on the outer periphery of the balancing inner tube assembly, and an inner protrusion is formed on the inner periphery of the balancing outer tube assembly. The outer protrusion is located on the upper side of the inner protrusion, and an outer chamber 6 and an inner chamber 3 are formed between the balancing inner tube assembly and the balancing outer tube assembly. The outer chamber 6 is connected to the outside through the outer pressure transmission hole 5 on the balancing outer tube assembly, and the inner chamber 3 is connected to the inside through the inner pressure transmission hole 4.

[0046] The outer protrusion is engaged with the inner circumference of the balancing outer tube assembly, and the inner protrusion is engaged with the inner circumference of the balancing inner tube assembly, so that the outer chamber 6 and the inner chamber 3 are isolated from each other.

[0047] When the step force balancing module is in the well, the fluid outside the balanced outer tube assembly can enter the outer chamber 6 through the external pressure transmission hole 5, and the fluid inside the balanced inner tube assembly can enter the inner chamber 3 through the internal pressure transmission hole 4. Since the internal pressure of the balanced inner tube assembly is greater than the external pressure of the balanced outer tube assembly, the step force acting on the telescopic tube structure can be balanced by the pressure difference between the inner chamber 3 and the outer chamber 6.

[0048] It should be noted that the balancing inner tube assembly can move axially relative to the balancing outer tube assembly to meet the overall telescopic requirements of the telescopic tube structure.

[0049] In this solution, the step force balancing module uses the axial force generated by the pressure difference between the inner and outer chambers to offset the step force, effectively improving the stress state of the pipe string and increasing the safety factor.

[0050] In addition, in some embodiments, the step force balancing module further includes a starting pin 9 that passes through the balancing outer tube assembly and is partially inserted into the balancing inner tube assembly. A positioning groove is provided on the outer periphery of the balancing inner tube assembly to accommodate the insertion of the starting pin 9, thereby limiting the axial relative displacement between the balancing inner tube assembly and the balancing outer tube assembly. When the telescopic tube structure carries an axial load that exceeds the bearing range of the starting pin 9, the starting pin 9 can be sheared off to allow the balancing inner tube assembly to move axially relative to the balancing outer tube assembly to achieve compensation. The provision of the starting pin 9 can ensure that the telescopic tube structure will not be in a displacement compensation state in advance when it is lowered, and shear pins with different shear values ​​and quantities can be installed according to the load safety range. A plurality of starting pins 9 can be provided at circumferential intervals.

[0051] According to actual needs, the starting pin 9 can position the balancing inner tube assembly at the upper limit position, that is, after the starting pin 9 is cut, the balancing inner tube assembly can only move downward from the upper limit position. Of course, in other embodiments, the balancing inner tube assembly can also be positioned at an intermediate position or a lower limit position.

[0052] Specifically, in some embodiments, the balancing inner tube assembly includes a balancing inner tube 2 and a balancing inner tube joint 7 connected to the upper end of the balancing inner tube 2, with the outer protrusion provided on the balancing inner tube joint 7. Referring to FIG1 , the balancing inner tube joint 7 is connected to the upper end of the balancing inner tube 2, and the upper end of the balancing inner tube 2 and the balancing inner tube joint 7 are each provided with a portion of the outer protrusion. The outer protrusion is at least partially sealingly engaged with the inner circumference of the balancing outer tube assembly to isolate the outer chamber 6 from the inner chamber 3.

[0053] Additionally, in some embodiments, a high-pressure seal 10 is sleeved on the outer periphery of the balancing inner pipe joint 7 and located on the outer protrusion. The high-pressure seal 10 improves the sealing performance between the balancing inner pipe joint 7 and the balancing outer pipe assembly, preventing leakage between the outer chamber 6 and the inner chamber 3. The high-pressure seal 10 may include O-rings at both ends and a V-shaped packing seal in the middle. The O-rings scrape away oil and sludge from the sealing surface, while the V-shaped packing seal provides the primary seal.

[0054] In some embodiments, a balancing inner tube sealing end head 8 is sleeved onto the outer periphery of the balancing inner tube joint 7 and positioned below the high-pressure seal 10. The balancing inner tube sealing end head 8 can press against the high-pressure seal 10. The balancing inner tube joint 7 is partially sleeved onto the balancing inner tube 2, and the two are positioned by a positioning pin 11; the balancing inner tube sealing end head 8 and the balancing inner tube joint 7 are also positioned by the positioning pin 11.

[0055] In addition, in some embodiments, the balancing outer tube assembly includes a balancing outer tube 1, a balancing sealing tube 13 connected to the lower end of the balancing outer tube 1, and a high-pressure seal 10 arranged on the inner circumferential surface of the balancing sealing tube 13. The balancing sealing tube 13 is partially inserted into the balancing outer tube 1, and the above-mentioned inner protrusion is formed by the balancing sealing tube 13. As shown in Figure 1, the inner chamber 3 is surrounded by the balancing outer tube 1, the balancing inner tube 2, the balancing inner tube joint 7 and the balancing sealing tube 13. A high-pressure seal 10 is provided between the balancing sealing tube 13 and the balancing inner tube 2 to improve the sealing performance between the two and avoid leakage in the inner chamber 3. The balancing sealing tube 13 and the balancing outer tube 1 are positioned by a positioning pin 11.

[0056] In some embodiments, the balancing outer tube assembly includes a balancing outer tube joint 12 partially inserted into the lower end of the balancing seal tube 13. The upper end of the balancing outer tube joint 12 presses against the high-pressure seal 10 on the inner circumference of the balancing seal tube 13. The balancing outer tube joint 12 is partially inserted into the balancing seal tube 13 and positioned by a positioning pin 11. The balancing outer tube joint 12 can limit the axial movement of the high-pressure seal 10, thereby maintaining it in the target position. The balancing inner tube 2 is sealingly engaged with the balancing outer tube joint 12 and extends from below it.

[0057] In addition, in some embodiments, the telescopic tube structure further includes a guide sliding module connected to the step force balancing module. The guide sliding module includes a guide outer tube assembly connected to the balancing outer tube assembly and a guide inner tube assembly connected to the balancing inner tube assembly. The guide inner tube assembly and the guide outer tube assembly engage with each other through a keyway to enable relative axial movement. One of the guide inner tube assembly and the guide outer tube assembly is provided with an axially extending key, and the other is provided with an axially extending slot. The key is received in the slot, thereby guiding relative axial movement of the two and restricting relative rotation of the two. Under the action of the guide sliding module, the inner tube portion of the telescopic tube structure moves axially relative to its outer tube portion without rotating.

[0058] In some embodiments, the guide outer tube assembly includes a guide outer tube 14, a guide outer tube joint 16 connected to the lower end of the guide outer tube 14, and a guide key 17 provided on the inner periphery of the guide outer tube joint 16. Referring to FIG2 , the guide outer tube joint 16 is partially sleeved on the guide outer tube 14 and positioned by a positioning pin 11 to limit relative rotation between the two. The guide key 17 is provided on the inner periphery of the guide outer tube joint 16, and correspondingly, a groove is provided on the outer periphery of the guide inner tube assembly to cooperate with the guide key 17. Of course, in other embodiments, the guide key 17 may also be provided on the outer periphery of the guide inner tube assembly, and a groove may also be provided on the inner periphery of the guide outer tube assembly.

[0059] In addition, in some embodiments, the guide outer tube assembly further includes a positioning end cap 18 that is partially inserted into the lower end of the guide outer tube connector 16. The guide key 17 is detachably disposed on the inner circumference of the guide outer tube connector 16, and the positioning end cap 18 presses against the lower end of the guide key 17. A strip-shaped positioning groove may be provided on the inner circumference of the guide outer tube connector 16 to partially accommodate the guide key 17. The positioning end cap 18 can press against the guide key 17 to prevent it from detaching.

[0060] Accordingly, in some embodiments, the guide inner tube assembly includes a guide inner tube 15, the outer circumference of which is provided with a guide groove 19 for accommodating the guide key 17. During installation, the guide inner tube 15 can be first inserted into the guide outer tube connector 16, followed by the guide key 17, and finally the positioning end 18. The guide key 17 can be a double-headed key, i.e., its two ends are arc-shaped.

[0061] In some embodiments, a high-pressure seal 10 is provided on the outer circumference of the upper end of the guide inner tube 15. The high-pressure seal 10 is joined to the inner circumference of the guide outer tube 14 to enhance the sealing performance between the guide inner tube 15 and the guide outer tube 14 and prevent leakage.

[0062] In addition, in some embodiments, the guide inner tube assembly further includes a guide inner tube sealing end head 20 partially sleeved on the upper end of the guide inner tube 15, and the guide inner tube sealing end head 20 presses the high-pressure seal 10. The guide inner tube sealing end head 20 is inserted between the upper ends of the guide inner tube 15 and the guide outer tube 14, and can press the high-pressure seal 10.

[0063] The guide sliding module can be connected to the upper end of the step force balancing module. As shown in FIG6 , the guide outer tube joint 16 is partially inserted into the balancing outer tube 1 , the two being threadedly connected and positioned by a locating pin 11 to restrict relative rotation. The guide inner tube 15 is inserted into the balancing inner tube joint 7 , the two being threadedly connected and positioned by a locating pin 11 . The lower end of the locating end 18 engages the upper end surface of the balancing inner tube joint 7 . The balancing inner tube joint 7 , the balancing outer tube 1 , and the locating end 18 enclose the outer chamber 6 described above.

[0064] In addition, in some embodiments, as shown in Figure 3 , the telescopic tube structure further includes an upper connector 21 connected to the upper end of the guide outer tube assembly. As shown in Figure 5 , the upper connector 21 can be inserted into the guide outer tube 14 , the two being threadedly connected and positioned by the positioning pin 11 .

[0065] In some embodiments, as shown in FIG4 , the telescopic tube structure further includes a lower connector 22 connected to the lower end of the balancing inner tube assembly. As shown in FIG8 , the lower end of the balancing inner tube 2 is partially inserted into the lower connector 22, the two being threadedly connected and positioned by a locating pin 11.

[0066] In some embodiments, multiple step force balancing modules can be set as needed, and the step force balancing modules can be connected in sequence. Referring to Figure 7, in the outer tube part, the lower end of the balancing outer tube joint 12 is inserted into the upper end of the balancing outer tube 1, and the two are threadedly connected and positioned by the positioning pin 11. In the inner tube part, the lower end portion of the balancing inner tube 2 is inserted into the balancing inner tube joint 7, and the lower end surface of the balancing outer tube joint 12 is engaged with the lower end surface of the balancing inner tube joint 7. The outer chamber 6 is surrounded by the balancing inner tube joint 7, the balancing outer tube joint 12 and the balancing outer tube 1.

[0067] Referring to Figures 9 and 10, Figure 9 shows the stress on the inner tube portion of a conventional telescopic tube, and Figure 10 shows the stress on the outer tube portion of a conventional telescopic tube, where A is the cross-sectional area at each position and P is the pressure. The overall stress on the inner tube and the overall stress on the outer tube are respectively:

[0068] F 内 =P i [(A4-A2)+(A8-A4)]+P o[(A5-A6)-(A5-A3)-(A3-A1)-(A8-A6)]

[0069] .....=P i (A8-A2)+P o (A1-A8)

[0070] F 外 =-P i [(A8-A9)+(A9-A12)]+P o [(A7-A10)+(A10-A11)-(A7-A8)]

[0071] .....=P i (A12-A8)+P o (A8-A11)

[0072] Referring to Figures 11 and 12, Figure 11 shows the stress on the inner tube portion of the telescopic tube of this solution, and Figure 12 shows the stress on the outer portion of the telescopic tube of this solution, where A is the cross-sectional area at each position, and P is the pressure. The overall stress on the inner tube and the overall stress on the outer tube are respectively:

[0073] F 内筒 =Pi[(A4-A2)+(A6-A4)-2(A8-A6)]+Po[(A5-A6)+2(A8-A6)-(A5-A1)]=Pi(3A6-A2-2A8)+Po(A1+2A8-3A6)

[0074] F 外筒 =Pi[2(A8-A6)-(A6-A9)-(A9-A12)]+Po[(A7-A11)-2(A8-A6)-(A7-A6)]=Pi(2A8+A12-3A6)+Po(3A6-2A8-A11)

[0075] The force comparison calculations of the traditional telescopic tube and the new telescopic tube were carried out under different working conditions. The results are shown in Tables 1 and 2.

[0076] Table 1 Force results of telescopic tubes under different parameters in the prior art

[0077] Table 2 Stress results of the telescopic tube structure of this scheme

[0078] Referring to the calculation results, it can be seen that under different working conditions, the step force of the telescopic tube structure of this scheme is much smaller than that of the traditional telescopic tube. This scheme uses the pressure difference to achieve axial force balance of the telescopic tube.

[0079] Thus far, various embodiments of the present disclosure have been described in detail. To avoid obscuring the concept of the present disclosure, some details known in the art have not been described. Based on the above description, those skilled in the art can fully understand how to implement the technical solutions disclosed herein.

[0080] Although some specific embodiments of the present disclosure have been described in detail through examples, those skilled in the art will understand that the above examples are for illustrative purposes only and are not intended to limit the scope of the present disclosure. Those skilled in the art will understand that the above embodiments may be modified or some technical features may be replaced with equivalents without departing from the scope and spirit of the present disclosure. In particular, as long as there are no structural conflicts, the various technical features mentioned in the various embodiments may be combined in any manner.

Claims

1. A telescopic tube structure, characterized in that, It includes a stepped force balance module. The stepped force balance module includes a balance outer tube assembly and a balance inner tube assembly that can axially move relative to the balance outer tube assembly. An outer protrusion is provided on the outer periphery of the balance inner tube assembly, and an inner protrusion is provided on the inner periphery of the balance outer tube assembly. The balance inner tube assembly and the balance outer tube assembly enclose an outer chamber (6) located above the outer protrusion and an inner chamber (3) located between the outer protrusion and the inner protrusion. The balance outer tube assembly is provided with an external pressure transmission hole (5) communicating with the outer chamber (6) and the outside of the balance outer tube assembly, and the balance inner tube assembly is provided with an internal pressure transmission hole (4) communicating with the inner chamber (3) and the inside of the balance inner tube assembly.

2. The telescopic tube structure according to claim 1, wherein, The stepped force balance module further includes a starting pin (9) that passes through the balance outer tube assembly and is partially inserted into the balance inner tube assembly.

3. The telescopic tube structure according to claim 1, characterized in that, The balance inner tube assembly includes a balance inner tube (2) and a balance inner tube joint (7) connected to the upper end of the balance inner tube (2). The outer protrusion is provided on the balance inner tube joint (7).

4. The telescopic tube structure according to claim 3, wherein, A high-pressure seal (10) located in the outer chamber (6) is sleeved on the outer periphery of the balance inner tube joint (7).

5. The telescopic tube structure according to claim 4, wherein, A balance inner tube sealing end (8) located below the high-pressure seal (10) is sleeved on the outer periphery of the balance inner tube joint (7).

6. The telescopic tube structure according to claim 5, wherein, The balance outer tube assembly includes a balance outer tube (1), a balance seal tube (13) connected to the lower end of the balance outer tube (1), and a high-pressure seal (10) provided on the inner peripheral surface of the balance seal tube (13).

7. The telescopic tube structure according to claim 6, wherein The balance outer tube assembly includes a balance outer tube joint (12) partially inserted into the lower end of the balance seal tube (13). The upper end of the balance outer tube joint (12) presses the high-pressure seal (10) on the inner peripheral surface of the balance seal tube (13).

8. The telescopic tube structure according to claim 1, wherein, It further includes a guiding and sliding module connected to the stepped force balance module. The guiding and sliding module includes a guiding outer tube assembly connected to the balance outer tube assembly and a guiding inner tube assembly connected to the balance inner tube assembly. The guiding inner tube assembly and the guiding outer tube assembly are keyway-fitted with each other and can move axially relative to each other.

9. The telescopic tube structure according to claim 8, characterized in that, The guiding outer tube assembly includes a guiding outer tube (14), a guiding outer tube joint (16) connected to the lower end of the guiding outer tube (14), and a guiding key (17) provided on the inner periphery of the guiding outer tube joint (16).

10. The telescopic tube structure according to claim 9, wherein, The guiding outer tube assembly further includes a positioning end (18) partially inserted into the lower end of the guiding outer tube joint (16). The guiding key (17) is detachably provided on the inner periphery of the guiding outer tube joint (16), and the positioning end (18) presses the lower end of the guiding key (17).

11. The telescopic tube structure according to claim 10, characterized in that, The guiding inner tube assembly includes a guiding inner tube (15). A guiding groove (19) for accommodating the guiding key (17) is provided on the outer periphery of the guiding inner tube (15).

12. The telescopic tube structure according to claim 11, wherein, A high-pressure seal (10) is provided on the outer periphery of the upper end of the guiding inner tube (15).

13. The telescopic tube structure according to claim 12, characterized in that, The guiding inner tube assembly further includes a guiding inner tube sealing end (20) partially sleeved on the upper end of the guiding inner tube (15), and the guiding inner tube sealing end (20) presses the high-pressure seal (10).

14. The telescopic tube structure according to claim 8, characterized in that, It further includes an upper joint (21) connected to the upper end of the guiding outer tube assembly.

15. The telescopic tube structure according to claim 1, characterized in that, It further includes a lower joint (22) connected to the lower end of the balance inner tube assembly.

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