Self-rotating traction device

Abstract

The application provides a self-rotation traction device, which comprises a shell, a transmission main shaft for connecting a casing pipe, the transmission main shaft being provided with a first central flow channel, a helical spline extending along an axial direction being arranged on an inner wall of a lower end of the transmission main shaft, and an elastic member being sleeved on the transmission main shaft, a leading shoe shaft being concentrically arranged in the shell, the leading shoe shaft being provided with a second central flow channel, and a helical spline groove capable of being matched with the helical spline being arranged on an outer wall surface of the leading shoe shaft, and a leading shoe pressure transmission sleeve being fixedly sleeved on the leading shoe shaft, wherein in a first state, the transmission main shaft can transmit drilling pressure applied by a well mouth to the leading shoe pressure transmission sleeve through the elastic member and the shell in sequence, and then transmit the drilling pressure to the leading shoe shaft to pull down the casing pipe, and in a second state, by continuously increasing the drilling pressure, the helical spline is screwed into the helical spline groove, so that the transmission main shaft can drive the leading shoe shaft and the leading shoe pressure transmission sleeve to rotate to destroy a rock pile, so that the self-rotation traction device can continue to pull down the casing pipe under the condition of encountering resistance.

Description

Technical Field

[0001] The invention belongs to the technical field of oil and gas drilling tools, and specifically relates to a self-rotating traction device. Background Art

[0002] During the oil drilling operation, casing needs to be lowered. In the prior art, a guide shoe is usually used to pull the casing into the wellbore.

[0003] During the casing lowering process, if the guide shoe encounters resistance from rock accumulation, when the resistance reaches a certain value, it will cause a jam. Even if the drilling pressure is continued, the casing cannot be pulled down. In this case, the drill string needs to be lifted up and then lowered to push the guide shoe into the well. If resistance is repeatedly encountered, the casing and guide shoe need to be repeatedly lifted up and lowered many times, resulting in very low casing lowering efficiency. It may even be impossible to pass through the blocked formation, seriously affecting the normal progress of the drilling operation. Summary of the Invention

[0004] In response to the above-mentioned technical problems, the present invention aims to provide a self-rotating traction device, which can generate self-rotation to destroy the rock pile by continuously increasing the drilling pressure when encountering resistance, thereby continuing to pull the casing down.

[0005] To this end, the present invention provides a self-rotating traction device, comprising: a cylindrical shell; a transmission main shaft for connecting a sleeve, the transmission main shaft being concentrically arranged in the shell and being rotatable relative to the shell, the transmission main shaft being provided with a first central flow channel, a helical spline extending along the axial portion on the inner wall of the lower end of the transmission main shaft, and an elastic member being sleeved on the transmission main shaft; a guide shoe shaft being concentrically arranged in the shell, the guide shoe shaft being provided with a second central flow channel, and a screw thread capable of matching the helical spline is provided on the outer wall of the guide shoe shaft a spiral spline groove; and a guide shoe pressure transmission sleeve fixedly mounted on the guide shoe shaft; wherein, in a first state, the transmission main shaft can transmit the drilling pressure applied at the wellhead to the guide shoe pressure transmission sleeve through the elastic member and the shell in sequence, and then transmit it to the guide shoe shaft to pull the casing downward; in a second state, by continuing to increase the drilling pressure, the spiral spline is screwed into the spiral spline groove, so that the transmission main shaft can drive the guide shoe shaft and the guide shoe pressure transmission sleeve to rotate to destroy the rock pile, so that the self-rotating traction device can continue to pull the casing downward in the event of resistance.

[0006] In one embodiment, the housing is constructed to include an upper shell, a middle shell, and a lower shell that are fixedly connected in sequence from top to bottom.

[0007] In one embodiment, a clamping limit member is fixed to the upper end of the elastic member, and a first tightening sleeve is installed at the lower end of the elastic member. The first tightening sleeve is sleeved on the transmission main shaft and can move along the transmission main shaft, and the lower end surface of the first tightening sleeve abuts against the upper end surface of the middle shell.

[0008] In one embodiment, an upper joint is fixedly connected to the upper end of the upper shell, an anti-wear sleeve is provided between the upper joint and the upper shell, and the clamping limiter is located axially inward of the anti-wear sleeve.

[0009] In one embodiment, the outer side of the guide shoe pressure transmission sleeve is provided with a step with the end face facing upward, and the lower end face of the guide shoe pressure transmission sleeve is configured as a conical surface, and the lower outer shell is sleeved on the guide shoe pressure transmission sleeve. In the first state, the lower end face of the lower outer shell can abut against the step, thereby transmitting the upper drilling pressure to the guide shoe pressure transmission sleeve, and then to the guide shoe shaft.

[0010] In one embodiment, the deformation L2 of the elastic member satisfies the following relationship:

[0011] L1 <L2<L3<L4

[0012] Among them, L1 refers to the initial distance between the lower end face of the lower shell and the step, L3 refers to the initial unscrewed distance of the helical spline, and L4 refers to the initial distance between the outer step end face formed at the upper end of the transmission main shaft and the upper end face of the upper joint.

[0013] In one embodiment, the end of the shoe guide shaft is configured as a spherical surface, and a plurality of ribs uniformly distributed in the circumferential direction are provided on the outer periphery of the spherical surface.

[0014] In one embodiment, the pitch of the helical spline is set to be in the range of 100-800 mm, and the helix angle of the helix formed by the helical extension of the helical spline is in the range of 5-85 degrees, the width of the helical spline is set to be in the range of 40-200 mm, and the depth is set to be in the range of 5-20 mm.

[0015] In one embodiment, an annular limiting groove is provided on the outer surface of the transmission main shaft, a through hole is provided on the side wall of the guide shoe shaft, an anti-drop pin block is installed in the through hole, the axial inner end of the anti-drop pin block extends into the annular limiting groove, and the axial width of the annular limiting groove is greater than the width of the anti-drop pin block.

[0016] In one embodiment, an anti-slip sleeve and a second tightening sleeve are mounted on the guide shoe shaft, the anti-slip sleeve is located radially outside the anti-pin drop block, and the two ends of the second tightening sleeve respectively tighten the lower end surface of the anti-slip sleeve and the upper end surface of the guide shoe pressure transmission sleeve.

[0017] Compared with the prior art, the advantages of this application are:

[0018] The self-rotating traction device according to the present invention can use drilling pressure to pull the casing into the rock pile under normal working conditions. In the event of resistance, the drilling pressure can be further increased to cause the self-rotating traction device to rotate automatically, thereby breaking the rock pile and allowing the casing to be pulled into the rock pile. This can effectively prevent the end of the guide shoe shaft from getting stuck, greatly improving the efficiency of casing running and increasing the success rate of casing running. In addition, the self-rotating traction device can also generate pressure pulses when encountering resistance. The pulse pressure can produce a certain degree of axial impact on the guide shoe shaft, which is also very beneficial for the self-rotating traction device to pull the casing. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] The present invention will be described below with reference to the accompanying drawings.

[0020] Figure 1 is a cross-sectional view of a self-rotating traction device according to the present invention.

[0021] Figure 2 Schematically shows Figure 1 The structure of the transmission main shaft in the self-rotating traction device is shown.

[0022] Figure 3 Schematically shows Figure 1 The structure of the shoe guide shaft in the self-rotating traction device is shown.

[0023] Figure 4 yes Figure 3 A sectional view of the guide shoe shaft shown.

[0024] Figure 5 Shows Figure 1 The structure of the guide shoe pressure transmission sleeve in the self-rotating traction device is shown.

[0025] In this application, all drawings are schematic drawings, which are only used to illustrate the principles of the present invention and are not drawn to scale. DETAILED DESCRIPTION

[0026] The present invention will be described below with reference to the accompanying drawings.

[0027] In the present application, it should be noted that the end of the self-rotating traction device according to the present invention lowered into the wellbore close to the wellhead is defined as the upper end or similar terms, and the end away from the wellhead is defined as the lower end or similar terms.

[0028] It should also be noted that the directional terms or qualifiers "upper", "lower", etc. used in this application are all directed to the attached drawings to which they are referred. Figure 1They are not intended to define the absolute positions of the components involved, but may vary depending on the specific situation.

[0029] Figure 1 FIG is a cross-sectional view of a self-rotating traction device 100 according to the present invention. Figure 1 As shown, the self-rotating traction device 100 includes a cylindrical housing 1, a transmission main shaft 2 for connecting to a casing, a guide shoe shaft 4 concentrically arranged within the housing 1, an elastic member 5 sleeved on the transmission main shaft 2, and a guide shoe pressure transmission sleeve 7 fixedly sleeved on the guide shoe shaft 4. The transmission main shaft 2 is concentrically arranged within the housing 1 and is rotatable relative to the housing 1. A first central flow channel 21 extending axially is defined within the transmission main shaft 2, and a second central flow channel 41 extending axially is defined within the guide shoe shaft 4. The first central flow channel 21 and the second central flow channel 41 are in communication with each other for the flow of drilling fluid.

[0030] According to the present invention, Figure 1 As shown, the lower inner wall of the transmission main shaft 2 is provided with a helical spline 22 extending axially. Simultaneously, the upper outer wall of the guide shoe shaft 4 is provided with a helical spline groove 42 that mates with the helical spline 22. The helical spline 22 and the helical spline groove 42 form a mating connection between the transmission main shaft 2 and the guide shoe shaft 4, allowing the transmission main shaft 2 to be screwed in or out relative to the guide shoe shaft 4, thereby achieving relative axial movement and rotation between the two shafts. Thus, the transmission main shaft 2 and the guide shoe shaft 4 can transmit torque via the helical spline 22 and the helical spline groove 42.

[0031] In actual use, the self-rotating traction device 100 is connected to the casing (not shown). During casing lowering, under normal operation, the wellhead rotary table applies weight-on-bit (WOB) to the drive shaft 2 through the casing. The drive shaft 2 transmits the WOB to the guide shoe shaft 4 via the elastic member 5, the housing 1, and the guide shoe pressure transmission sleeve 7. At this point, the self-rotating traction device 100 is in a first operating state, with the helical spline 22 and the helical spline groove 42 not engaged. The drive shaft 2 and the guide shoe shaft 4 are disconnected, and the self-rotating traction device 100 uses WOB to pull the casing into the wellbore.

[0032] When the end of the guide shoe shaft 4 encounters resistance, the helical spline 22 can be screwed into the helical spline groove 42 by continuing to increase the bit pressure. Under the action of the helical spline 22 and the helical spline groove 42, the transmission main shaft 2 can drive the guide shoe shaft 4 and the guide shoe pressure transmission sleeve 7 to rotate, thereby breaking the rock pile, thereby allowing the self-rotating traction device 100 to continue to pull the casing down despite the resistance. At this time, the self-rotating traction device 100 is in the second working state.

[0033] like Figure 1 and Figure 2As shown, the upper end of the transmission main shaft 2 is configured with a connecting portion. The connecting portion has a diameter greater than that of the main body of the transmission main shaft 2, thereby forming a downwardly facing outer stepped end surface 26 at the upper end of the transmission main shaft 2. In one embodiment, the connecting portion is configured as an internally tapered coupling buckle, through which the transmission main shaft 2 is fixedly connected to the sleeve. The function of the outer stepped end surface 26 will be described below.

[0034] According to the present invention, Figure 1 As shown, the housing 1 is constructed to include an upper housing 11, a middle housing 12, and a lower housing 13, which are fixedly connected in sequence from top to bottom. The transmission main shaft 2 is located in the upper housing 11 and the middle housing 12, respectively, and the shoe shaft 4 is located in the lower housing 13. The middle housing 12 can be a centralizer (spiral centralizer or straight edge centralizer), which can stabilize the self-rotating traction device 100, greatly enhancing its performance.

[0035] In one embodiment, the upper housing 11, the middle housing 12, and the lower housing 13 are all fixedly connected by positive and negative conical connecting buckles. This connection method is convenient and fast to install, and can effectively ensure the stability of the connection.

[0036] According to one embodiment of the present invention, the elastic member 5 is a butterfly spring.

[0037] like Figure 1 As shown, a compression limiter 51 is fixed to the upper end of the elastic member 5. The compression limiter 51 can be, for example, a compression nut, which is fixedly mounted on the transmission main shaft 2 through threads.

[0038] A first tightening sleeve 52 is mounted on the lower end of the elastic member 5. The first tightening sleeve 52 fits over the transmission main shaft 2 and can move along the transmission main shaft 2. The first tightening sleeve 52 is cylindrical, and the inner wall of the upper end is provided with an inwardly extending annular boss. The inner wall of the annular boss fits over the transmission main shaft 2. The upper end surface of the middle housing 12 is correspondingly located within the upper housing 11, thereby forming an upward-facing shoulder within the upper housing 11. The lower end surface of the first tightening sleeve 52 abuts against the shoulder formed on the upper end surface of the middle housing 12.

[0039] In this embodiment, the butterfly spring can be pre-designed to set a certain bearing capacity. Within the range of this bearing capacity, the transmission main shaft 2 can compress the butterfly spring through the clamping limiter 51 under the action of drilling pressure to transmit the drilling pressure to the first tightening sleeve 52. The disc spring tightening sleeve 7 then transmits the drilling pressure to the middle shell 12 and the lower shell 13 in turn, so that the lower end face of the lower shell 13 is in contact with the step 71 (see below) of the guide shoe pressure transmission sleeve 7, thereby transmitting the drilling pressure to the guide shoe pressure transmission sleeve 7 and the guide shoe shaft 4.

[0040] In order to ensure that the lower end surface of the lower shell 13 can contact the step 71 of the guide shoe pressure transmission sleeve 7, the deformation amount L2 of the disc spring is greater than the initial distance L1 between the lower end surface of the lower shell 13 and the step 71 of the guide shoe pressure transmission sleeve 7. The initial state of the self-rotating traction device 100 is the state before entering the well, and the initial distance is the distance in the initial state. That is, L1 <L2。

[0041] like Figure 1 As shown, the upper end of the upper housing 11 is fixedly connected to an upper joint 24. An anti-wear sleeve 23 is disposed between the upper joint 24 and the upper housing 11, and the compression stopper 51 is located axially inward of the anti-wear sleeve 23. The anti-wear sleeve 23 can, for example, be constructed to include a wear-resistant dynamic sleeve fixed to the transmission main shaft 2 and a wear-resistant static sleeve fixed to the inner wall of the upper joint 24. Thus, the wear-resistant sleeve 23 effectively prevents wear between the transmission main shaft 2 and the upper joint 24.

[0042] like Figure 1 and Figure 5 As shown, the shoe guide pressure transmission sleeve 7 is constructed into a cylindrical shape. A step 71 with the end face facing upward is provided on the outer side of the shoe guide pressure transmission sleeve 7. In one embodiment, the inner hole 73 of the shoe guide pressure transmission sleeve 7 is provided with an internal thread, and at the same time, a section of external thread is provided on the corresponding outer wall surface of the shoe guide shaft 3. The shoe guide pressure transmission sleeve 7 is sleeved on the shoe guide shaft 3 and is fixedly connected by the internal thread and the external thread. The lower end face of the shoe guide pressure transmission sleeve 7 is constructed into a conical surface 72, which facilitates the insertion of the guide sleeve. The lower shell 13 is sleeved on the shoe guide pressure transmission sleeve 7, and the lower end face of the lower shell 13 is correspondingly located above the step 71, and the lower shell 13 can slide axially relative to the shoe guide pressure transmission sleeve 7.

[0043] like Figure 3 As shown, the end of the shoe guide shaft 4 can be configured as a spherical surface 44, which can play a good guiding role. At the same time, a plurality of ribs 8 uniformly distributed in the circumference can be provided on the periphery of the spherical surface 44, which can play a good guiding role.

[0044] According to one embodiment of the present invention, taking a 7" drill bit as an example, the pitch of the helical spline 22 on the transmission main shaft 2 is set to be within the range of 100-800 mm, and the helix angle of the helical line formed by the helical extension of the helical spline 22 is set to be within the range of 5-85 degrees. The width of the helical spline 22 is set to be within the range of 40-200 mm, and the depth is set to be within the range of 5-20 mm. Accordingly, the helical spline groove 42 on the guide shoe shaft 4 is adapted to the helical spline 22. In order to facilitate the cooperation between the helical spline groove 42 and the helical spline 22, the width and depth of the helical spline groove 42 are set to be slightly larger than the width and depth of the helical spline 22.

[0045] like Figures 2 to 4As shown, an annular limiting groove 25 is provided on the outer surface of the transmission main shaft 2, and a through hole 45 is provided on the side wall of the guide shoe shaft 4. An anti-drop pin block 6 is installed in the through hole 45, and the axial inner end of the anti-drop pin block 6 extends into the annular limiting groove 25. During the process of pulling the casing into the well by the self-rotating traction device 100, the anti-drop pin block 6 can play a good anti-drop role and effectively prevent the guide shoe shaft 4 from falling. During installation, the anti-drop pin block 6 passes through the through hole 45 from the outside to the inside and is inserted into the annular limiting groove 25. In this embodiment, the axial width of the annular limiting groove 25 is greater than the axial width of the anti-drop pin block 6.

[0046] In order to prevent the anti-drop pin block 6 from falling out during operation, in one embodiment, an anti-drop sleeve 61 and a second tightening sleeve 62 are mounted on the guide shoe shaft 4. The anti-drop sleeve 61 is located radially outside the anti-drop pin block 6 and can effectively prevent the anti-drop pin block 6 from falling out. The inner wall of the anti-drop sleeve 61 is provided with a protrusion, and the guide shoe shaft 4 is provided with a limiting step with the end face facing downward. The two ends of the second tightening sleeve 62 respectively press against the lower end face of the anti-drop sleeve 61 and the upper end face of the guide shoe pressure transmission sleeve 7, so that the protrusion on the inner wall of the anti-drop sleeve 61 presses against the limiting step, thereby forming an axial limit for the anti-drop sleeve 61.

[0047] In this embodiment, the value of the width of the annular limit groove 25 minus the axial width of the anti-drop pin block 6 is greater than the maximum value of the axial movement of the transmission main shaft 2 relative to the guide shoe shaft 4, so as to ensure that when the guide shoe shaft 4 moves upward to the highest point relative to the transmission main shaft 2, the axial end face position of the first eccentric hole 211 can coincide with the axial end face position of the second eccentric hole 411.

[0048] In an unillustrated embodiment, a first eccentric hole is provided within the power spindle 2, communicating with the first central channel 21. The first eccentric hole is located axially inward of the helical spline groove 22. Simultaneously, a second eccentric hole is provided at the upper end of the guide shoe shaft 4, communicating with the second central channel 41. The axially outer end of the first eccentric hole forms a first axial impact surface 211, while the upper end surface of the guide shoe shaft 4 forms a second axial impact surface 411. During the axial reciprocating motion of the power spindle 2, the distance between the first axial impact surface 211 and the second axial impact surface 411 changes accordingly.

[0049] During operation of the self-rotating traction device 100, before the guide shoe shaft 4 rotates upward relative to the main transmission shaft 2 and reaches its highest point, the first central channel 21 connects to the second central flow channel 41 through the first and second eccentric holes, sequentially. At this point, a certain distance exists between the axial end face of the first eccentric hole (the first axial impact surface 211) and the axial end face of the second eccentric hole (the second axial impact surface 411), and the first eccentric hole is fully open. When the guide shoe shaft 4 reaches its highest point, the first axial impact surface 211 of the main transmission shaft 2 and the second axial impact surface 411 of the guide shoe shaft 4 contact and overlap, causing the first and second eccentric holes to overlap and minimize the contact area. At this point, the first central channel 21 connects to the second central flow channel 41 through the overlapping area between the first and second eccentric holes. The reduced area of ​​the overlapping area creates a throttling effect, generating a pressure pulse. This generated pressure pulse can act on the upper end face of the guide shoe shaft 4. As a result, the guide shaft 4 can generate a certain degree of axial impact under the action of the pulse pressure, which is very beneficial to the traction of the casing by the self-rotating traction device 100.

[0050] In order to ensure that the first axial impact surface 211 of the power main shaft 2 and the second axial impact surface 411 of the shoe guide shaft 4 can contact and overlap, the maximum distance between the first axial impact surface 211 and the second axial impact surface 411 is set to be smaller than the maximum distance between the outer step end surface 26 of the upper end of the transmission main shaft 2 and the upper end surface of the upper joint 24. The maximum distance between the first axial impact surface 211 and the second axial impact surface 411 is the initial distance L3 between the two when the helical spline 22 is not initially screwed into the helical spline groove 42. The maximum distance between the outer step end surface 26 of the upper end of the transmission main shaft 2 and the upper end surface of the upper joint 24 is the initial distance L4 between the two in the initial state. That is, L3 <L4。

[0051] According to the present invention, to ensure that when the elastic member 5 reaches its maximum compression contraction, the transmission main shaft 2 can be screwed into the helical spline groove 42 of the shoe guide shaft 4 via the helical spline, thereby rotating the shoe guide shaft 4 and the shoe guide pressure transmission sleeve 7, the deformation L2 of the elastic member 5 is less than the initial unscrewed distance L3 of the helical spline 22. Therefore, the deformation L2 of the elastic member 5 satisfies the following relationship:

[0052] L1 <L2<L3<L4

[0053] Among them, L1 refers to the initial distance between the lower end face of the lower shell 13 and the step 71, L3 refers to the initial unscrewed distance of the helical spline 22 (that is, the maximum distance between the first axial impact surface 211 and the second axial impact surface 411), and L4 refers to the initial distance between the outer step end face 26 formed at the upper end of the transmission main shaft 2 and the upper end face of the upper joint 24.

[0054] The following briefly describes the working process of the self-rotating traction device 100 according to the present invention. First, the self-rotating traction device 100 is connected to the casing through the transmission main shaft 2 and is placed in an initial state. The casing is then lowered. During the casing lowering process, the self-rotating traction device 100 can pull the casing down. The wellhead rotary table applies drilling pressure to the transmission main shaft 2 through the casing. The transmission main shaft 2 compresses the elastic member 5 through the anti-wear sleeve 23 and the clamping limit member 51. Within the pre-set bearing capacity range of the elastic member 5, the elastic member 5 is compressed, and then the drilling pressure is transmitted to the first tightening sleeve 52. The first tightening sleeve 52 transmits the drilling pressure to the middle shell 12 and the lower shell 13 in turn, and pushes the lower shell 13 downward until the lower end face of the lower shell 13 contacts the step 71 of the guide shoe pressure transmission sleeve 7, thereby transmitting the drilling pressure to the guide shoe pressure transmission sleeve 7 and the guide shoe shaft 7. As a result, the guide shoe shaft 7 can pull the casing down under the action of the drilling pressure. During the running process, when the end of the guide shoe shaft 4 encounters resistance, the drilling pressure is continuously increased until the elastic member 5 reaches its maximum value under compression. The transmission main shaft 2 is screwed into the helical spline groove 42 of the guide shoe shaft 4 through the helical spline 22, so that the guide shoe shaft 4 rotates under the cooperation of the helical spline 22 and the helical spline groove 42, and drives the guide shoe pressure transmission sleeve 7 to rotate synchronously. This enables the self-rotating traction device 100 to generate self-rotation, thereby breaking the rock pile and continuing the running, effectively avoiding the end of the guide shoe shaft 4 from being stuck, which is very beneficial to improving the casing running efficiency.

[0055] The self-rotating traction device 100 according to the present invention can utilize the drilling pressure to pull the casing into the rock pile under normal working conditions. In addition, when encountering resistance, the self-rotating traction device 100 can continue to rotate by increasing the drilling pressure to break the rock pile, thereby continuing to pull the casing into the rock pile. This can effectively prevent the end of the guide shoe shaft 4 from getting stuck, which is very beneficial to improving the efficiency of casing running and the success rate of casing running. In addition, the self-rotating traction device 100 can also generate pressure pulses when encountering resistance. The pulse pressure can produce a certain degree of axial impact on the guide shoe shaft 4, which is also very beneficial to the self-rotating traction device 100 pulling the casing.

[0056] In the description of the present invention, the terms "first" and "second" are used for descriptive purposes only and should not be understood to indicate or imply relative importance or implicitly specify the number of the technical features indicated. Therefore, a feature specified as "first" or "second" may explicitly or implicitly include one or more of the features. In the description of the present invention, "plurality" means two or more, unless otherwise specifically defined.

[0057] In the present invention, unless otherwise expressly specified or limited, the terms "mounted," "connected," "connect," "fixed," etc. should be understood broadly. For example, they may refer to fixed, detachable, or integral connections; mechanical or electrical connections; direct or indirect connections through an intermediary; or internal communication between two components. Those skilled in the art will understand the specific meanings of the above terms in the present invention based on specific circumstances.

[0058] Throughout this specification, reference to terms such as "one embodiment," "some embodiments," "examples," "specific examples," or "some examples" means that a specific feature, structure, material, or characteristic described in conjunction with that embodiment or example is included in at least one embodiment or example of the present invention. In this specification, schematic representations of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples.

[0059] Finally, it should be noted that the above description is merely a preferred embodiment of the present invention and does not constitute any limitation to the present invention. Although the present invention has been described in detail with reference to the aforementioned embodiments, it is still possible for those skilled in the art to modify the technical solutions described in the aforementioned embodiments or to replace some of the technical features therein with equivalents. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principles of the present invention shall be included in the scope of protection of the present invention.

Claims

1. A self-rotating traction device comprising: A cylindrical shell (1); a transmission main shaft (2) for connecting the sleeve, the transmission main shaft being concentrically arranged in the housing and rotatable relative to the housing, the transmission main shaft being provided with a first central flow channel (21), a helical spline (22) extending along an axial portion being provided on the inner wall of the lower end of the transmission main shaft, and an elastic member (5) being sleeved on the transmission main shaft; A shoe guide shaft (4) is concentrically arranged in the housing, the shoe guide shaft is provided with a second central flow channel (41), and a helical spline groove (42) capable of matching the helical spline is provided on the outer wall surface of the shoe guide shaft; and A guide shoe pressure transmission sleeve (7) fixedly sleeved on the guide shoe shaft; The housing is constructed to include an upper housing (11), a middle housing (12), and a lower housing (13) that are fixedly connected in sequence from top to bottom. A pressing limiter (51) is fixed at the upper end of the elastic member, and a first tightening sleeve (52) is installed at the lower end of the elastic member. The first tightening sleeve is sleeved on the transmission main shaft and can move along the transmission main shaft, and the lower end surface of the first tightening sleeve abuts against the upper end surface of the middle shell. The upper end of the upper shell is fixedly connected to an upper joint (24), an anti-wear sleeve (23) is provided between the upper joint and the upper shell, and the pressing limiter is located axially inside the anti-wear sleeve. An annular limiting groove (25) is provided on the outer surface of the transmission main shaft, a through hole (45) is provided on the side wall of the shoe guide shaft, an anti-drop pin block (6) is installed in the through hole, the axial inner end of the anti-drop pin block extends into the annular limiting groove, and the axial width of the annular limiting groove is greater than the width of the anti-drop pin block. In the first state, the transmission main shaft can transmit the bit pressure applied by the wellhead to the guide shoe pressure transmission sleeve through the elastic member and the housing in sequence, and then transmit it to the guide shoe shaft to pull the casing downward. In the second state, by continuing to increase the bit pressure, the helical spline is screwed into the helical spline groove, so that the transmission main shaft can drive the guide shoe shaft and the guide shoe pressure transmission sleeve to rotate to break the rock pile, so that the self-rotating traction device can continue to pull the casing into the casing in the event of resistance. The outer side of the guide shoe pressure transmission sleeve is provided with a step (71) with the end surface facing upward, and the lower end surface of the guide shoe pressure transmission sleeve is configured as a cone surface (72). The lower shell is sleeved on the guide shoe pressure transmission sleeve. In the first state, the lower end surface of the lower shell can abut against the step, thereby transmitting the upper drilling pressure to the guide shoe pressure transmission sleeve and further to the guide shoe shaft.

2. The self-rotating traction device according to claim 1, characterized in that: The deformation L2 of the elastic member satisfies the following relationship: L1< L2< L3< L4 Wherein, L1 refers to the initial distance between the lower end face of the lower housing and the step, L3 refers to the initial unscrewed distance of the helical spline, and L4 refers to the initial distance between the outer step end face (26) formed at the upper end of the transmission main shaft and the upper end face of the upper joint.

3. The self-rotating traction device according to claim 1, characterized in that: The end of the shoe guide shaft is configured as a spherical surface (44), and a plurality of ribs (8) evenly distributed in the circumferential direction are provided on the outer periphery of the spherical surface.

4. The self-rotating traction device according to claim 1, characterized in that: The pitch of the helical spline is set to be in the range of 100-800 mm, and the helix angle of the helix formed by the helical extension of the helical spline is in the range of 5-85 degrees, the width of the helical spline is set to be in the range of 40-200 mm, and the depth is set to be in the range of 5-20 mm.

5. The self-rotating traction device according to claim 1, characterized in that: An anti-slip sleeve (61) and a second tightening sleeve (62) are sleeved on the guide shoe shaft. The anti-slip sleeve is located radially outside the anti-drop pin block. The two ends of the second tightening sleeve respectively tighten the lower end surface of the anti-slip sleeve and the upper end surface of the guide shoe pressure transmission sleeve.

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