Downhole emergency drive tool and control method

Abstract

The present invention relates to the technical field of oil and gas resource drilling engineering, and particularly to a downhole emergency transmission tool and a control method. The downhole emergency transmission tool is used in cooperation with a rotary clutch drilling tool, and includes a housing, a transmission shaft and a central shaft. The housing is arranged in a cylindrical structure; the transmission shaft is located inside the housing and is coaxial with the housing; the first end of the central shaft is connected to the transmission shaft and can drive the transmission shaft to rotate together. The second end of the central shaft passes through the housing. The central shaft includes a first state separated from the housing and a second state of driving the housing to rotate together. When the rotary clutch drilling tool is in normal use, the central shaft only drives the drive shaft of the rotary clutch drilling tool connected to the transmission shaft to rotate. After the rotary clutch drilling tool fails, the central shaft drives the housing to rotate, and the housing is connected to the driven shaft of the rotary clutch drilling tool. At this time, the rotary clutch drilling tool is equivalent to a drill pipe, and the drill string can complete the directional operation through conventional directional methods.

Description

Technical Field

[0001] The present invention relates to the technical field of oil and gas resource drilling engineering, and particularly to a downhole emergency transmission tool and a control method therefor. Background Art

[0002] Directional drilling refers to a drilling technology in which drilling is carried out according to the pre-designed well inclination and azimuth to achieve the expected wellbore trajectory. The existing directional drilling technologies can be divided into sliding directional drilling technology and rotary steerable drilling technology according to different working modes of the steering tools.

[0003] The sliding directional drilling technology and the rotary steerable drilling technology have different applicable ranges. Therefore, it is necessary to select different drilling methods for different working conditions during the drilling process. The rotary steerable drilling technology is expensive and is only suitable for use in key wells and high-benefit blocks. In relatively stable reservoir areas, sliding direction is still the main directional drilling method. As the horizontal section increases, the friction resistance is relatively large during the traditional sliding directional drilling process, and the problem of weight transfer resistance becomes prominent.

[0004] Based on this, the rotary clutch drilling tool came into being. This tool integrates the advantages of sliding directional and rotary steerable drilling technologies. During the drilling process, the upper drill string transmits the driving torque to the bottom hole assembly (BHA) through this tool, and this driving torque is used to balance the reaction torque transmitted by the lower positive displacement motor. By adjusting the magnitude of the driving torque, the switching between compound drilling and directional drilling during the drilling process can be achieved. During the sliding directional drilling process, the drill string can rotate throughout the process, reducing the friction resistance in the horizontal section and thus reducing the phenomenon of weight transfer resistance.

[0005] For example, a document with the publication number of CN111852334A discloses an "anti-torque automatic balancing device, drilling pipe string and method for positive displacement motor", including an upper sub, a core barrel, a lower sub fixedly arranged at the lower end of the core barrel, and an automatic balancing assembly arranged between the outer wall of the core barrel and the inner wall of the upper sub. When the drilling fluid displacement is equal to the first predetermined value, the frictional torque (driving torque) generated between the upper sub and the core barrel is equal to the reaction torque generated on the outer shell of the positive displacement motor for directional drilling. When the drilling fluid displacement is higher than the first predetermined value, the frictional torque generated between the upper sub and the core barrel is greater than the reaction torque generated on the outer shell of the positive displacement motor, so that the core barrel drives the outer shell of the positive displacement motor to rotate for compound drilling.

[0006] The rotational power of the bottom drilling assembly below the above-mentioned rotary clutch drilling tool comes from the drill string above the rotary clutch drilling tool. Once this tool fails, it is difficult for the upper sub to drive the core barrel to rotate, and then the lower sub connected to the core barrel cannot transmit the rotational power to the positive displacement motor, resulting in the inability to complete directional drilling. Summary of the Invention

[0007] One of the objectives of the present invention is to provide a downhole emergency pressure transmission tool, which can complete directional drilling when the rotary clutch drilling tool fails, avoid pulling out the drill string, and reduce economic losses.

[0008] To achieve the above objective, the technical solution of the present invention is as follows:

[0009] A downhole emergency transmission tool, used in cooperation with a rotary clutch drilling tool, includes a housing, a transmission shaft, and a central shaft. The housing is arranged in a cylindrical structure; the transmission shaft is located inside the housing and is coaxial with the housing; the first end of the central shaft is connected to the transmission shaft and can drive the transmission shaft to rotate together. The second end of the central shaft passes through the housing. The central shaft includes a first state separated from the housing and a second state of driving the housing to rotate together.

[0010] Optionally, both the transmission shaft and the central shaft are arranged in a cylindrical structure. The central shaft can perform axial movement relative to the housing. First external splines and second external splines are arranged at intervals along the axial direction on the outer periphery of the central shaft. First internal splines capable of meshing with the first external splines are arranged on the inner periphery of the housing. Second internal splines meshing with the second external splines are arranged on the inner periphery of the transmission shaft. When the central shaft is in the first state, the second external splines are meshed with the second internal splines, and the first external splines are disengaged from the first internal splines. When the central shaft is in the second state, the first external splines are meshed with the first internal splines.

[0011] Optionally, it further includes a first locking assembly and a second locking assembly. Both the first locking assembly and the second locking assembly include a locked state and an unlocked state. The first locking assembly is configured to axially limit the central shaft when the central shaft is in the first state. Initially, the first locking assembly is in the locked state. The second locking assembly is configured to axially limit the central shaft when the central shaft is in the second state. Initially, the second locking assembly is in the unlocked state.

[0012] Optionally, the first locking assembly includes a shear pin, and both ends of the shear pin are respectively connected to the central shaft and the transmission shaft.

[0013] Optionally, the second locking assembly includes a locking pin and an elastic member. The locking pin is arranged radially on one of the central shaft and the housing. An annular limiting groove for inserting the locking pin is arranged on the other of the central shaft and the housing. The elastic member is configured to keep the locking pin in a tendency to insert into the limiting groove.

[0014] Optionally, the housing includes a cylinder and a sealing end cover. The sealing end cover is disposed at one end of the cylinder and is sealingly connected to the cylinder. A through hole for the central shaft to pass through is formed in the sealing end cover, and the sealing end cover is in sealing sliding connection with the central shaft.

[0015] Optionally, the locking pin is disposed on the sealing end cover. The sealing end cover is provided with a mounting hole that penetrates the inner wall and the outer wall of the sealing end cover in the radial direction. A cover plate is screwed to one end of the mounting hole that penetrates the outer wall of the sealing end cover. One end of the elastic member located in the mounting hole is connected to the cover plate, and the other end is connected to the locking pin.

[0016] Optionally, the length of the second internal spline is greater than the length of the first internal spline. When the central shaft is in the second state, the first external spline remains engaged with the first internal spline.

[0017] Optionally, wedge-shaped guiding surfaces are provided at both ends of the protrusions of the first external spline and / or the first internal spline.

[0018] Another object of the present invention is to provide a control method for controlling the above-mentioned downhole emergency transmission tool with a shear pin as the first locking component. The control method is as follows:

[0019] After the rotary clutch drilling tool fails, drill pressure is applied on the ground. The shear pin shaft is cut off under the action of the drill pressure. The central shaft moves downward under the action of the thrust to engage the first external spline and the first internal spline, and the second locking component switches to the locked state.

[0020] The beneficial effects of the present invention are as follows: The downhole emergency transmission tool in the present invention can be used in cooperation with the rotary clutch drilling tool, and can still transmit torque to the BHA after the rotary clutch drilling tool fails, so as to complete the directional operation through the conventional directional method, avoid pulling out the drill string for repair, and reduce economic losses. Description of the Drawings

[0021] Figure 1 is a schematic structural diagram of the downhole emergency transmission tool in the embodiment of the present invention when the rotary clutch drilling tool is working normally;

[0022] Figure 2 is a schematic structural diagram of the downhole emergency transmission tool in the embodiment of the present invention after the rotary clutch drilling tool fails;

[0023] Figure 3 is a schematic structural diagram of the central shaft;

[0024] Figure 4 is a schematic structural diagram of the sealing end cover.

[0025] In the figure, 1 is the central axis; 11 is the first external spline; 12 is the second external spline; 13 is the limiting groove;

[0026] 2 is the transmission shaft; 21 is the second internal spline;

[0027] 3 is the housing; 31 is the cylinder body; 311 is the first internal spline; 32 is the sealing end cover; 321 is the cover plate; 322 is the mounting hole;

[0028] 4 is the shear pin;

[0029] 5 is the elastic member;

[0030] 6 is the locking pin. Specific embodiments

[0031] The present invention will be further described in detail below with reference to the accompanying drawings and embodiments. It can be understood that the specific embodiments described herein are only used to explain the present invention, rather than limiting the present invention. Additionally, it should be noted that for the sake of description, only parts related to the present invention rather than all structures are shown in the accompanying drawings.

[0032] In the description of the present invention, unless otherwise clearly defined and limited, the terms "connected", "connected to", and "fixed" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or integrated; it can be a mechanical connection or an electrical connection; it can be directly connected, or indirectly connected through an intermediate medium, and it can be the internal communication of two components or the interaction relationship between two components. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0033] In the present invention, unless otherwise clearly defined and limited, the first feature being "above" or "below" the second feature may include the direct contact between the first and second features, or may include the situation where the first and second features are not in direct contact but in contact through other features therebetween. Moreover, the first feature being "above", "above and over", and "on top of" the second feature includes the first feature being directly above and obliquely above the second feature, or simply indicating that the horizontal height of the first feature is higher than that of the second feature. The first feature being "below", "below and under", and "beneath" the second feature includes the first feature being directly below and obliquely below the second feature, or simply indicating that the horizontal height of the first feature is lower than that of the second feature.

[0034] In the description of this embodiment, the orientation or positional relationships such as "upper", "lower", "left", and "right" are based on the orientation or positional relationships shown in the drawings. They are only for the convenience of description and simplifying the operations, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation. Therefore, it should not be construed as a limitation to the present invention. In addition, the terms "first" and "second" are only used for differentiation in description and have no special meanings.

[0035] The present invention provides a downhole emergency transmission tool. This tool is arranged between a rotary clutch drilling tool and a drill string and is used to transmit the torque of the upper drill string to the BHA after the rotary clutch drilling tool fails. During the normal operation of the rotary clutch drilling tool, this downhole emergency transmission tool does not work and does not affect the normal directional operation through the rotary clutch drilling tool. After the rotary clutch drilling tool fails, a large weight on bit is applied from the surface to the downhole to trigger this tool to enter the working mode. The BHA obtains the rotary power of the upper drill string through this tool. At this time, the rotary clutch drilling tool can be equivalent to a drill pipe, and the directional well engineer can still complete the directional operation through traditional directional methods, effectively avoiding economic losses caused by the failure of the rotary clutch drilling tool.

[0036] In this embodiment, the component in the existing rotary clutch tool that is connected to the BHA and drives the BHA to rotate is defined as the driven shaft, and the component that is connected to the upper drill string and is driven to rotate by the upper drill string is defined as the drive shaft. The driven shaft includes two states: rotating together with the drive shaft and not rotating with the drive shaft. When the rotary clutch tool fails, it is difficult for the drive shaft to transmit the rotary power of the upper drill string to the BHA. For example, in the document with the publication number CN111852334A, the upper sub is equivalent to the drive shaft, and the core barrel and the lower sub connected to the core barrel are equivalent to the driven shaft. When the automatic balance assembly fails, the power of the upper sub cannot be transmitted to the housing of the positive displacement motor, and the directional drilling work is difficult to complete.

[0037] Figures 1-4 Shown is the downhole emergency transmission tool in one embodiment of the present invention. This tool includes a central shaft 1, a transmission shaft 2, and a housing 3. The housing 3 is arranged in a cylindrical structure, and its first end can be connected to the driven shaft of the rotary clutch drilling tool. The transmission shaft 2 is located inside the housing 3 and is coaxial with the housing 3. The first end of the transmission shaft 2 can be connected to the drive shaft of the rotary clutch assembly. The first end of the central shaft 1 is connected to the transmission shaft 2 and can drive the transmission shaft 2 to rotate together. The second end passes through the housing 3 and can be connected to the upper drill string. The central shaft 1 includes a first state of being separated from the housing 3 and a second state of driving the housing 3 to rotate together.

[0038] During the normal operation of the above-mentioned downhole emergency transmission tool in a rotary clutch drilling tool, the central shaft 1 transmits the rotational power of the upper drill string to the drive shaft of the rotary clutch drilling tool, without affecting the normal use of the rotary clutch drilling tool. When the rotary clutch drilling tool fails and it becomes difficult to transmit the rotational power, the central shaft 1 moves axially relative to the drive shaft 2 and the housing 3. The rotational power of the upper drill string is transmitted to the driven shaft through the central shaft 1, and the BHA obtains the rotational power of the upper drill string through this tool. The rotary clutch drilling tool can be equivalent to a drill pipe. At this time, the directional function can be completed by traditional directional methods, effectively avoiding the tripping caused by the failure of the rotary clutch drilling tool and reducing economic losses. It can be understood that when the central shaft 1 is in the second state, it can either disengage from the drive shaft 2 or continue to drive the drive shaft 2 to rotate, without affecting the transmission of torque from the central shaft 1 to the BHA.

[0039] Reference Figure 1 As shown, the conversion between the first state and the second state of the central shaft 1 is achieved by the axial movement of the central shaft 1 relative to the housing 3. The drive shaft 2 is also arranged in a cylindrical structure. First external splines 11 and second external splines 12 are arranged at intervals along the axial direction on the outer periphery of the central shaft 1, and first internal splines 311 and second internal splines 21 are respectively arranged corresponding to the inner periphery of the housing 3 and the inner periphery of the drive shaft 2. When the central shaft 1 is in the first state, the second external splines 12 are engaged with the second internal splines 21, while the first external splines 11 are disengaged from the first internal splines 311. When the central shaft 1 needs to be converted from the first state to the second state, the central shaft 1 moves axially to make the first external splines 11 engaged with the first internal splines 311, and the housing 3 can rotate driven by the central shaft 1.

[0040] The central shaft 1 is also arranged in a cylindrical structure, and drilling fluid can flow into the drive shaft 2 through the central shaft 1. In order to form a seal, the housing 3 includes a cylinder body 31 and a sealing end cover 32. The sealing end cover 32 is arranged at one end of the cylinder body 31 and is provided with a through hole in the center for the central shaft 1 to pass through. The sealing end cover 32 is hermetically and slidably connected to the central shaft 1 and the housing 3 through sealing rings. Specifically, a plurality of sealing rings are arranged at intervals along the axial direction of the central shaft 1. In this embodiment, the housing 3 adopts a split structure. When assembling this downhole emergency transmission tool, first place the drive shaft 2 into the cylinder body 31, insert the central shaft 1 into the cylinder body 31, and then connect the sealing end cover 32 and the cylinder body 31 to complete the assembly.

[0041] In this embodiment, the length of the second internal spline 21 is greater than that of the first internal spline 311. When the housing 3 rotates with the central shaft 1, the transmission shaft 2 also rotates with the central shaft 1, so that the transmission shaft 2 is stationary relative to the housing 3, which can reduce the friction between the transmission shaft 2 and the housing 3 and reduce energy loss. Exemplarily, the length of the second internal spline 21 is twice that of the first internal spline 311, and the length of the second external spline 12 is also twice that of the first external spline 11. In the initial state, the meshing length of the second external spline 12 and the second internal spline 21 is half of the length of the second external spline 12. When the first external spline 11 meshes with the first internal spline 311, the second external spline 12 and the second internal spline 21 are in a fully meshed state. To ensure that the first external spline 11 can be inserted into the first internal spline 311 at any angle of the central shaft 1 to achieve meshing connection, wedge-shaped guiding surfaces are provided at both ends of the first external spline 11 and / or the first internal spline 311 (a spline is a circumferential coupling member composed of alternately arranged protrusions and grooves). More specifically, the depth of the second external spline 12 can be set to half of the depth of the first external spline 11 to smoothly insert into the transmission shaft 2 located in the housing 3.

[0042] The downhole emergency transmission tool in this embodiment further includes a first locking assembly and a second locking assembly to prevent the central shaft 1 from axially moving relative to the housing 3 and the transmission shaft 2 under unexpected circumstances (when the rotary clutch drilling tool is in normal use). Both the first locking assembly and the second locking assembly include a locked state and an unlocked state. The first locking assembly is configured to axially limit the central shaft 1 when the central shaft 1 is in the first state. Initially, the first locking assembly is in the locked state. The second locking assembly is configured to axially limit the central shaft 1 when the central shaft 1 is in the second state. Initially, the second locking assembly is in the unlocked state.

[0043] After the first locking assembly is unlocked, the central shaft 1 can axially move relative to the transmission shaft 2. To achieve automatic unlocking, the first locking assembly includes a shear pin 4. The two ends of the shear pin 4 are respectively inserted into the central shaft 1 and the transmission shaft 2 along the radial direction. When the axial thrust between the transmission shaft 2 and the central shaft 1 is greater than the preset thrust at which the shear pin 4 is cut, the shear pin 4 is cut, and the central shaft 1 and the transmission shaft 2 axially move under the action of the thrust. In this embodiment, the change in the axial thrust between the transmission shaft 2 and the central shaft 1 can be achieved by increasing the weight on bit on the ground. That is, when switching the state of the central shaft 1 relative to the housing 3, only the weight on bit needs to be increased.

[0044] The second locking assembly includes a locking pin 6 and an elastic member 5. The locking pin 6 is arranged radially in one of the central shaft 1 and the outer shell 3, and a limiting groove 13 for the locking pin 6 to insert is arranged on the other of the central shaft 1 and the outer shell 3. The elastic member 5 is configured to keep the locking pin 6 in a tendency to insert into the limiting groove 13. In this embodiment, a pin mounting groove is radially formed on the sealing end cover 32, and both the locking pin 6 and the elastic member 5 are located in the pin mounting groove. Correspondingly, the limiting groove 13 is formed on the central shaft 1. In order to avoid the rotation angle of the central shaft 1 interfering with the insertion of the locking pin 6, the limiting groove 13 is arranged as an annular groove. For the convenience of processing, the sealing end cover 32 is radially provided with a mounting hole 322 penetrating the inner wall and the outer wall of the sealing end cover 32. A cover plate 321 is screwed at one end of the mounting hole 322 penetrating the outer wall of the sealing end cover 32. The cover plate 321 and the hole wall of the mounting hole 322 jointly enclose to form the pin mounting groove. One end of the elastic member 5 is connected to the cover plate 321, and the other end is connected to the locking pin 6. The elastic member 5 can be a compression spring in a compressed state or an elastic rubber sheet, etc. When the central shaft 1 moves to a position where the limiting groove 13 and the locking pin 6 are at the same circumferential height, the locking screw is inserted into the limiting groove 13 to axially limit the central shaft 1.

[0045] The present invention also provides a control method for controlling the state of the above-mentioned downhole emergency transmission tool. The specific control method is as follows: When the rotary clutch drilling tool used in cooperation with the downhole emergency transmission tool functions normally, due to the axial limit of the shear pin shaft, the second external spline 12 remains meshed with the second internal spline 21, while the first external spline 11 and the first internal spline 311 are in a disengaged state. The rotational power of the upper drill string is only transmitted to the drive shaft of the rotary clutch drilling tool; after the rotary clutch drilling tool fails, the drill pressure is applied on the ground. The shear pin shaft is cut off under the action of the drill pressure, and the axial limiting effect fails. The central shaft 1 moves downward to make the first external spline 11 and the first internal spline 311 mesh until the locking pin 6 enters the limiting groove 13. At this time, the rotational power of the upper drill string can not only be transmitted to the drive shaft of the rotary clutch drilling tool, but also be transmitted to the driven shaft of the rotary clutch drilling tool, ensuring that the directional operation can still be completed by the conventional directional method after the rotary clutch drilling tool fails, avoiding pulling out the drill string and reducing the economic loss.

[0046] Obviously, the above-mentioned embodiments of the present invention are only examples for clearly explaining the present invention, rather than limiting the implementation manners of the present invention. For those of ordinary skill in the art, various obvious changes, re-adjustments and substitutions can be made without departing from the protection scope of the present invention. It is not necessary and impossible to list all the implementation manners here. Any modifications, equivalent substitutions and improvements made within the spirit and principle of the present invention shall be included in the protection scope of the claims of the present invention.

Claims

1. An underground emergency transmission tool, which is used in cooperation with a rotary clutch drilling tool, characterized in that, it includes: a housing (3), and the housing (3) is arranged in a cylindrical structure; a transmission shaft (2), which is located inside the housing (3) and coaxial with the housing (3); a central shaft (1), the first end of the central shaft (1) is connected to the transmission shaft (2) and can drive the transmission shaft (2) to rotate together, the second end of the central shaft (1) passes through the housing (3), and the central shaft (1) includes a first state separated from the housing (3) and a second state of driving the housing (3) to rotate together; a first locking assembly and a second locking assembly, both the first locking assembly and the second locking assembly include a locked state and an unlocked state, the first locking assembly is configured to axially limit the central shaft (1) when the central shaft (1) is in the first state, initially, the first locking assembly is in the locked state, and the second locking assembly is configured to axially limit the central shaft (1) when the central shaft (1) is in the second state, initially, the second locking assembly is in the unlocked state.

2. The underground emergency transmission tool according to claim 1, characterized in that, both the transmission shaft (2) and the central shaft (1) are arranged in a cylindrical structure, the central shaft (1) can perform axial movement relative to the housing (3), a first external spline (11) and a second external spline (12) are arranged at intervals along the axial direction on the outer periphery of the central shaft (1), a first internal spline (311) capable of meshing with the first external spline (11) is arranged on the inner periphery of the housing (3), and a second internal spline (21) capable of meshing with the second external spline (12) is arranged on the inner periphery of the transmission shaft (2); when the central shaft (1) is in the first state, the second external spline (12) meshes with the second internal spline (21), and the first external spline (11) is disengaged from the first internal spline (311); when the central shaft (1) is in the second state, the first external spline (11) meshes with the first internal spline (311).

3. The underground emergency transmission tool according to claim 1, characterized in that, the first locking assembly includes a shear pin (4), and both ends of the shear pin (4) are respectively connected to the central shaft (1) and the transmission shaft (2).

4. The underground emergency transmission tool according to claim 1, characterized in that, the second locking assembly includes a locking pin (6) and an elastic member (5), the locking pin (6) is arranged radially on one of the central shaft (1) and the housing (3), and a limiting groove (13) for the locking pin (6) to insert is arranged on the other of the central shaft (1) and the housing (3), and the elastic member (5) is configured to keep the locking pin (6) in a tendency to insert into the limiting groove (13).

5. The underground emergency transmission tool according to claim 4, characterized in that, The housing (3) includes a cylinder body (31) and a sealing end cover (32). The sealing end cover (32) is arranged at one end of the cylinder body (31) and is hermetically connected to the cylinder body (31). A through hole for the central shaft (1) to pass through is formed in the sealing end cover (32), and the sealing end cover (32) is hermetically and slidably connected to the central shaft (1).

6. The downhole emergency transmission tool according to claim 5, wherein, the locking pin (6) is arranged on the sealing end cover (32). The sealing end cover (32) is provided with a mounting hole (322) that penetrates the inner wall and the outer wall of the sealing end cover (32) in the radial direction. One end of the mounting hole (322) that penetrates the outer wall of the sealing end cover (32) is screwed with a cover plate (321). One end of the elastic member (5) located in the mounting hole (322) is connected to the cover plate (321), and the other end is connected to the locking pin (6).

7. The downhole emergency transmission tool according to any one of claims 2-6, wherein, the length of the second internal spline (21) is greater than the length of the first internal spline (311). When the central shaft (1) is in the second state, the first external spline (11) remains engaged with the first internal spline (311).

8. The downhole emergency transmission tool according to any one of claims 2-6, wherein, wedge-shaped guiding surfaces are arranged at both ends of the protrusions of the first external spline (11) and / or the first internal spline (311).

9. A control method, wherein, for controlling the downhole emergency transmission tool according to any one of claims 3-6, the control method is as follows: After the rotary clutch drilling tool fails, drill pressure is applied on the ground. The shear pin shaft is cut off under the action of the drill pressure. The central shaft (1) moves downward under the action of the thrust force to engage the first external spline (11) with the first internal spline (311), and the second locking assembly switches to the locked state.

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