An underground emergency transmission tool and an underground emergency transmission method

Abstract

The present invention relates to an underground emergency transmission tool and an underground emergency transmission method. The underground emergency transmission tool includes a central shaft, an upper central shaft housing, a lower central shaft housing, a transmission shaft, and a sealing end cover assembly. The upper central shaft housing is used to connect the upper drill string, the lower central shaft housing is used to connect the driven shaft of the rotary clutch drilling tool, and the transmission shaft is used to connect the drive shaft of the rotary clutch drilling tool. The upper central shaft housing is coaxially sleeved outside the upper end of the central shaft, and the inner side wall of the upper central shaft housing is in transmission cooperation with the central shaft through a first spline structure. The upper end of the lower central shaft housing is provided with a sealing end cover assembly. The lower central shaft housing is coaxially sleeved outside the lower end of the central shaft, and the inner side wall of the lower central shaft housing is in transmission cooperation with the central shaft through a second spline structure or the second spline structures of the inner side wall of the lower central shaft housing and the central shaft are axially offset from each other. The transmission shaft is coaxially sleeved between the lower end of the central shaft and the lower central shaft housing, and the transmission shaft is in transmission cooperation with the central shaft through a third spline structure.

Description

Technical Field

[0001] The present invention relates to the field related to oil and gas resource drilling engineering, and particularly relates to a downhole emergency drive tool and a downhole emergency drive method. Background Art

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

[0003] The sliding directional drilling technique and the rotary steerable drilling technique 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 technique 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 drag pressure becomes prominent.

[0004] The rotary clutch drilling tool is a new type of directional drilling tool that integrates the advantages of sliding steering and rotary steerable drilling techniques. During the drilling process, the upper drill string transmits the driving torque to the bottom hole assembly (BHA) through this tool. This driving torque is used to balance the reverse 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 is 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 drag pressure phenomenon.

[0005] During the drilling process, the rotational movement of the upper drill string is transmitted to the lower drill string through the rotary clutch drilling tool. Once this tool fails, directional drilling cannot be completed. Therefore, to ensure the reliability of the tool during operation, it is necessary to develop a downhole drive tool and a control method in the case of tool failure to ensure that directional drilling can be completed when the tool fails, avoid pulling out the drill string, and reduce economic losses.

[0006] The publication number of the application CN104563908B discloses a "Friction and Torque Reduction Torque Clutch Device and Its Method", which includes an upper sub, a lower sub, an electrical connector, an intermediate sub, and a push cylinder body. The upper and lower ends of the piston shaft are respectively arranged in the intermediate sub and the lower sub. An electromagnetic control valve is arranged in the intermediate sub, and a jaw clutch is arranged in the lower sub. The outer teeth of the jaw clutch are installed at the lower end of the piston shaft. An electronic board and a sensor for receiving information transmitted from the ground are arranged in the sealing sleeve. This device can control the smooth transmission or separation of torque of the drill string during drilling as needed, which is beneficial to reducing the friction and torque of the drill string, reducing or preventing drilling drag, and improving the drilling technology level of highly deviated wells, horizontal wells, and extended reach wells. However, it lacks an emergency mechanism for tool failure. Once the device fails underground, the power of the upper drill string cannot be transmitted to the BHA, and the drill string must be pulled out of the well.

[0007] The publication number of the application CN111852334A discloses a "Counter-torque Automatic Balancing Device, Drilling String and Method for Positive Displacement Motor", which includes an upper sub, a core barrel, a lower sub fixedly arranged at the lower end of the core barrel, and an automatic balancing component arranged between the outer wall of the core barrel and the inner wall of the upper sub. When the displacement of the drilling fluid is equal to the first predetermined value, a friction torque is generated between the upper sub and the core barrel, which is equal to the counter-torque generated on the outer shell of the positive displacement motor for directional drilling. When the displacement of the drilling fluid is higher than the first predetermined value, the friction torque generated between the upper sub and the core barrel is greater than the counter-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. However, this tool lacks an emergency device. Once it fails, the power of the upper drill string cannot be transmitted to the BHA.

[0008] The publication number of the application CN218299716U discloses a "Transmission Mechanism of a Mechanical Emergency Starting Device", which includes a housing and an energy storage transmission component. The energy storage transmission component includes a slider, a swing arm, a pressing block, a driving rod, and a spring arranged between the pressing block and the housing. A set of energy storage spring groups are respectively arranged between the two ends of the slider and the housing. The energy storage spring group includes a spring support member longitudinally slidably arranged in the housing, an energy storage spring arranged between the spring support member and the housing, and a connecting rod. One end of the connecting rod is rotatably arranged at one end of the slider, and the other end of the connecting rod is rotatably arranged on the spring support member. The spring support member moves with the connecting rod and can reciprocally slide in the housing. However, this tool has a complex structure and cannot meet the requirements of the downhole environment. Summary of the Invention

[0009] The present invention provides a downhole emergency transmission tool and a downhole emergency transmission method to solve one or several of the technical problems existing in the prior art.

[0010] The technical solution of the present invention to solve the above technical problems is as follows: An underground emergency transmission tool, comprising a central shaft, an upper central shaft housing, a lower central shaft housing, a transmission shaft and a sealing end cover assembly. The upper central shaft housing, the lower central shaft housing and the transmission shaft are all in a cylindrical structure. The upper central shaft housing is used to connect the upper drill string. The lower central shaft housing is used to connect the driven shaft of the rotary clutch drilling tool. The transmission shaft is used to connect the drive shaft of the rotary clutch drilling tool;

[0011] The upper central shaft housing is coaxially sleeved outside the upper end of the central shaft, and the inner side wall of the upper central shaft housing is in transmission cooperation with the central shaft through a first spline structure; The upper end of the lower central shaft housing is provided with a sealing end cover assembly, and the sealing end cover assembly is hermetically sleeved on the outer side wall of the middle part of the central shaft; The lower central shaft housing is coaxially sleeved outside the lower end of the central shaft, and the inner side wall of the lower central shaft housing is in transmission cooperation with the central shaft through a second spline structure or the inner side walls of the lower central shaft housing and the central shaft are axially offset from each other's second spline structures;

[0012] The transmission shaft is coaxially sleeved between the lower end of the central shaft and the lower central shaft housing, and the transmission shaft is in transmission cooperation with the central shaft through a third spline structure; The central shaft can axially move relative to the upper central shaft housing, the lower central shaft housing and the transmission shaft, and the third spline structure is located below the second spline structure.

[0013] The beneficial effects of the present invention are as follows: The present invention is used in conjunction with various rotary clutch drilling tools. During the normal operation of the rotary clutch drilling tool, this tool is not triggered, and it does not affect the directional drilling operation through the rotary clutch drilling tool; After the rotary clutch drilling tool fails, there is no need to pull out the drill string, and the underground emergency transmission tool of the present invention can be triggered to achieve emergency transmission.

[0014] On the basis of the above technical solution, the present invention can also be improved as follows.

[0015] Further, the central shaft is a hollow structure, and the central shaft includes an upper shaft section and a lower shaft section, and the lower end of the upper shaft section is detachably connected to the upper end of the lower shaft section.

[0016] The beneficial effect of adopting the above further solution is: By using a central shaft with a hollow structure, the central shaft can be driven to move up and down by blocking the upper end of the central shaft to achieve pressure buildup, thereby realizing the triggering operation of the emergency transmission tool.

[0017] Further, the upper end of the upper shaft is located within the upper central shaft housing, and the lower end of the upper shaft extends out from the lower end of the upper central shaft housing. A first limiting step is provided on the inner side wall of the upper central shaft housing, and a second limiting step is provided on the outer side wall of the upper shaft. The upper end of the upper shaft is inserted into the upper central shaft housing from the lower end of the upper central shaft housing, and the second limiting step abuts against the first limiting step; the first spline structure is located below the first limiting step.

[0018] The beneficial effect of adopting the above further solution is that by setting the first limiting step and the second limiting step, the upper shaft can only be inserted from the lower end of the upper central shaft housing and limited within the upper central shaft housing, and the upper central shaft housing can effectively limit the upper shaft, preventing the upper shaft from disengaging from the upper end of the upper central shaft housing.

[0019] Further, the upper shaft above the second limiting step is adapted to abut against the upper central shaft housing above the first limiting step. The upper central shaft housing above the first limiting step is provided with an annular sandwich cavity with an open upper end. A first through hole communicating with the annular sandwich cavity is opened on the inner side wall of the upper central shaft housing, and a second through hole is opened on the upper shaft above the second limiting step;

[0020] Under normal working conditions, the second through hole is located above the first through hole; under emergency working conditions, the first through hole and the second through hole are in one-to-one correspondence and communication.

[0021] The beneficial effect of adopting the above further solution is that by setting the annular sandwich cavity, the first through hole and the second through hole, after the entire emergency transmission tool is under pressure, pressure balance can be achieved through the communication of the first through hole, the second through hole and the annular sandwich cavity, preventing the central shaft from continuously moving axially downward.

[0022] Further, a clamping structure is provided on the sealing end cover assembly, and a clamping groove is provided on the outer side wall of the central shaft. When the central shaft moves relative to the sealing end cover assembly to a preset position, the clamping structure is clamped in the clamping groove.

[0023] The beneficial effect of adopting the above further solution is that the setting of the clamping structure is beneficial to maintaining the emergency transmission tool in an emergency working state.

[0024] Further, the clamping structure includes a spring and a limiting post. A limiting groove is opened on the inner side wall of the sealing end cover assembly, and the limiting post is elastically connected in the limiting groove through the spring.

[0025] Further, a through channel is formed in the side wall of the sealing end cover assembly. A connecting cover is arranged outside the channel. The connecting cover and the channel enclose to form the limiting groove. One end of the spring is connected to the connecting cover, and the other end of the spring is connected to the limiting post.

[0026] Further, the lower end of the central shaft is located above the lower end of the transmission shaft, and the lower end of the transmission shaft is located above the lower end of the lower central shaft housing.

[0027] Further, a spherical pressure holding member is further included. The outer diameter of the spherical pressure holding member is smaller than the inner diameter of the upper central shaft housing and not less than the inner diameter of the central shaft.

[0028] The beneficial effect of adopting the above further solution is that by using the spherical pressure holding member, the spherical pressure holding member can be put into the emergency transmission tool by means of ball dropping for triggering.

[0029] An underground emergency transmission method is realized by using the above underground emergency transmission tool. The upper central shaft housing is connected to the upper drill string, the lower central shaft housing is connected to the driven shaft of the rotary clutch drilling tool, and the transmission shaft is connected to the driving shaft of the rotary clutch drilling tool;

[0030] The underground emergency transmission method includes:

[0031] Under normal working conditions, the rotary clutch drilling tool operates normally. The inner side wall of the upper central shaft housing and the central shaft are in transmission cooperation through the first spline structure. The inner side walls of the lower central shaft housing and the central shaft are axially staggered with respect to the second spline structure. The transmission shaft and the central shaft are in transmission cooperation through the third spline structure. The upper drill string transmits power to the driving shaft of the rotary clutch drilling tool through the transmission shaft, and the driven shaft of the rotary clutch drilling tool does not receive the power of the upper drill string;

[0032] Under emergency conditions, the rotary clutch drilling tool fails. The upper opening of the central shaft is blocked to hold pressure. The central shaft moves downward under the action of fluid pressure. The inner side wall of the upper central shaft housing and the central shaft are in transmission cooperation through the first spline structure, so that the inner side wall of the lower central shaft housing and the central shaft are in transmission cooperation through the second spline structure. The transmission shaft and the central shaft are in transmission cooperation through the third spline structure. The power of the upper drill string is respectively transmitted to the driving shaft and the driven shaft of the rotary clutch drilling tool through the central shaft, realizing the emergency drive of the rotary clutch drilling tool.

[0033] The beneficial effects of the present invention are as follows: For the downhole emergency transmission method of the present invention, after the emergency transmission tool is triggered, the power of the upper drill string can be directly transmitted to the driven shaft of the rotary clutch drilling tool. The rotary clutch drilling tool can be equivalent to a drill pipe, ensuring that the directional well engineer can complete the directional operation through the conventional directional drilling method, avoiding tripping out of the hole, and reducing the economic losses caused by the failure of the rotary clutch drilling tool. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] Figure 1 is a schematic structural diagram of the downhole emergency transmission tool of the present invention under normal working conditions;

[0035] Figure 2 is Figure 1 an enlarged structural diagram of part A in

[0036] Figure 3 is Figure 1 an enlarged structural diagram of part B in

[0037] Figure 4 is a schematic structural diagram of the downhole emergency transmission tool of the present invention under emergency working conditions;

[0038] Figure 5 is Figure 4 an enlarged structural diagram of part C in

[0039] Figure 6 is Figure 4 an enlarged structural diagram of part D in

[0040] Figure 7 is a schematic structural diagram of the sealing end cover assembly of the present invention.

[0041] In the drawings, the list of components represented by each reference numeral is as follows:

[0042] 100, upper shaft segment; 101, lower shaft segment; 102, second limiting step; 103, second through hole; 104, clamping groove;

[0043] 200, upper central shaft housing; 201, first limiting step; 202, annular sandwich cavity; 203, first through hole;

[0044] 300, lower central shaft housing;

[0045] 400, transmission shaft;

[0046] 500, sealing end cover assembly; 501, channel; 502, spring; 503, limiting post; 504, connecting cover; 505, sealing ring;

[0047] 600, first spline structure; 601, second spline structure; 602, third spline structure;

[0048] 700. Spherical pressure-holding part. Specific embodiments

[0049] The principles and features of the present invention will be described below in conjunction with the accompanying drawings. The examples given are only for explaining the present invention and are not intended to limit the scope of the present invention.

[0050] As Figures 1 to 7 shown, a downhole emergency transmission tool in this embodiment includes a central shaft, an upper central shaft housing 200, a lower central shaft housing 300, a transmission shaft 400, and a sealing end cap assembly 500. The upper central shaft housing 200, the lower central shaft housing 300, and the transmission shaft 400 are all in a cylindrical structure. The upper central shaft housing 200 is used to connect the upper drill string. The lower central shaft housing 300 is used to connect the driven shaft of the rotary clutch drilling tool. The transmission shaft 400 is used to connect the drive shaft of the rotary clutch drilling tool.

[0051] The upper central shaft housing 200 is coaxially sleeved outside the upper end of the central shaft. The inner side wall of the upper central shaft housing 200 is in transmission cooperation with the central shaft through a first spline structure 600. The upper end of the lower central shaft housing 300 is provided with a sealing end cap assembly 500. The sealing end cap assembly 500 is sealingly sleeved on the outer side wall of the middle part of the central shaft. The lower central shaft housing 300 is coaxially sleeved outside the lower end of the central shaft. The inner side wall of the lower central shaft housing 300 is in transmission cooperation with the central shaft through a second spline structure 601 or the inner side walls of the lower central shaft housing 300 and the central shaft are axially offset with respect to their respective second spline structures.

[0052] The transmission shaft 400 is coaxially sleeved between the lower end of the central shaft and the lower central shaft housing 300. The transmission shaft 400 is in transmission cooperation with the central shaft through a third spline structure 602. The central shaft can move axially relative to the upper central shaft housing 200, the lower central shaft housing 300, and the transmission shaft 400. The third spline structure 602 is located below the second spline structure 601.

[0053] Among them, two groups of spline structures are provided on the lower central shaft housing and the corresponding central shaft in this embodiment. The two groups of spline structures are respectively used to transmit torque to the drive shaft during the normal operation of the rotary clutch drilling tool and to the driven shaft in the case of the failure of the rotary clutch drilling tool.

[0054] As Figures 1 to 6 shown, the central shaft in this embodiment is a hollow structure. The central shaft includes an upper shaft section 100 and a lower shaft section 101. The lower end of the upper shaft section 100 is detachably connected to the upper end of the lower shaft section 101. By using a hollow central shaft, the pressure can be held by blocking the upper end of the central shaft to drive the central shaft to move up and down, thereby realizing the triggering operation of the emergency transmission tool.

[0055] Specifically, the first spline structure 600 of this embodiment includes a first spline and a first spline groove. One of the first spline and the first spline groove is arranged on the outer side wall of the upper shaft section 100, and the other is arranged on the inner side wall of the upper central shaft housing 200. The second spline structure 601 includes a second spline and a second spline groove. One of the second spline and the second spline groove is arranged on the outer side wall of the lower shaft section 101, and the other is arranged on the inner side wall of the lower central shaft housing 300. The second spline and the second spline groove can be engaged for transmission or axially offset without transmission cooperation. The third spline structure 602 includes a third spline and a third spline groove. One of the third spline and the third spline groove is arranged on the outer side wall of the lower shaft section 101, and the other is arranged on the inner side wall of the lower central shaft housing 300. The length of the third spline structure on the lower side of the lower shaft section is twice the axial length of the second spline structure. In the initial state, the third spline structure on the lower side of the lower shaft section is partially engaged with the spline groove of the transmission shaft, and the engagement length is half of the length of the third spline structure. The second spline on the upper side of the lower shaft section is disengaged from the second spline groove of the lower central shaft housing. After the tool is triggered, the central shaft moves downward, the second spline on the upper side of the lower shaft section is engaged with the second spline groove of the lower central shaft housing, and at the same time, the engagement depth of the third spline on the lower side of the lower shaft section with the third spline groove on the transmission shaft increases. After the tool triggering process ends, the splines on the upper and lower sides of the lower shaft section are respectively in a fully engaged state with their corresponding spline grooves. The second spline on the upper side of the lower shaft section is designed as a wedge-shaped plane to ensure that the second spline can be engaged with the second spline groove at any circumferential angle after the lower shaft section stops rotating. The depth of the third spline groove of the lower central shaft housing is half of that of the third spline groove of the transmission shaft, and the end face of the third spline groove is designed as a wedge-shaped plane to ensure that the spline can be engaged with the spline groove at any circumferential angle after the central shaft stops rotating.

[0056] As Figures 1 to 6 shown, the upper end of the upper shaft section 100 of this embodiment is located inside the upper central shaft housing 200, the lower end of the upper shaft section 100 extends out from the lower end of the upper central shaft housing 200. A first limiting step 201 is provided on the inner side wall of the upper central shaft housing 200, and a second limiting step 102 is provided on the outer side wall of the upper shaft section 100. The upper end of the upper shaft section 100 is inserted into the upper central shaft housing 200 from the lower end of the upper central shaft housing 200 and the second limiting step 102 abuts against the first limiting step 201; the first spline structure 600 is located below the first limiting step 201. By providing the first limiting step and the second limiting step, the upper shaft section can only be inserted into the upper central shaft housing from the lower end and be limited inside the upper central shaft housing, and the upper central shaft housing can effectively limit the upper shaft section to prevent the upper shaft section from disengaging from the upper end of the upper central shaft housing.

[0057] As Figure 2 and Figure 5As shown, the upper shaft segment 100 above the second limiting step 102 of this embodiment is adapted and abutted against the upper central shaft housing 200 above the first limiting step 201. The upper central shaft housing 200 above the first limiting step 201 is provided with an annular sandwich cavity 202 with an open upper end. A first through hole 203 communicating with the annular sandwich cavity 202 is formed on the inner side wall of the upper central shaft housing 200. A second through hole 103 is formed on the upper shaft segment 100 above the second limiting step 102. Under normal working conditions, the second through hole 103 is located above the first through hole 203. Under emergency working conditions, the first through hole 203 and the second through hole 103 are in one-to-one correspondence and communication. By providing the annular sandwich cavity, the first through hole and the second through hole, after the entire emergency transmission tool is subjected to pressure buildup, pressure balance can be achieved through the communication of the first through hole, the second through hole and the annular sandwich cavity, avoiding continuous axial downward movement of the central shaft. Among them, in the initial state of the tool, the axial distance between the first through hole and the second through hole is the same as the length of the second spline on the lower shaft segment, ensuring that the fluid buildup above is just released after the second spline on the lower shaft segment is fully engaged.

[0058] As Figure 3 , Figure 6 and Figure 7 As shown, the sealing end cover assembly 500 of this embodiment is provided with a clamping structure. A clamping groove 104 is provided on the outer side wall of the central shaft. When the central shaft moves to a preset position relative to the sealing end cover assembly 500, the clamping structure is clamped in the clamping groove 104. The setting of the clamping structure is beneficial to maintaining the emergency transmission tool in an emergency working state. Among them, the clamping groove 104 preferably adopts an annular structure. The outer side wall of the sealing end cover assembly 500 is hermetically connected to the inner side wall of the lower central shaft housing 300 through a sealing ring 505. The inner side wall of the sealing end cover assembly 500 is hermetically connected to the outer side wall of the lower shaft segment 101 through a sealing ring 505. The clamping structure is used to seal the drilling fluid inside the tool and lock the central shaft after the tool is triggered, avoiding the disengagement of the upper spline of the central shaft from the spline groove of the lower central shaft housing caused by the upward lifting of the drill string, resulting in tool failure.

[0059] As Figure 3 , Figure 6 and Figure 7 As shown, the clamping structure of this embodiment includes a spring 502 and a limiting post 503. A limiting groove is formed on the inner side wall of the sealing end cover assembly 500. The limiting post 503 is elastically connected in the limiting groove through the spring 502.

[0060] As Figure 7As shown, a through channel 501 is formed in the side wall of the sealing end cap assembly 500. A connecting cover 504 is provided outside the channel 501. The connecting cover 504 and the channel 501 enclose the limiting groove. One end of the spring 502 is connected to the connecting cover 504, and the other end of the spring 502 is connected to the limiting post 503.

[0061] As Figures 1 to 6 shown, the lower end of the central shaft of this embodiment is located above the lower end of the transmission shaft 400, and the lower end of the transmission shaft 400 is located above the lower end of the lower central shaft housing 300.

[0062] As Figure 1 、 Figure 2 、 Figure 4 and Figure 5 shown, the emergency transmission tool of this embodiment further includes a spherical pressure holding member 700. The outer diameter of the spherical pressure holding member 700 is smaller than the inner diameter of the upper central shaft housing 200 and not smaller than the inner diameter of the central shaft. By using the spherical pressure holding member, the spherical pressure holding member can be put into the emergency transmission tool by the method of dropping a ball for triggering.

[0063] In the emergency transmission tool of this embodiment, the lower part of the transmission shaft is connected to the drive shaft of the rotary clutch drilling tool. The hollow structure of the transmission shaft is used to provide a channel for the drilling fluid to flow downward. The lower part of the lower central shaft housing is connected to the driven shaft of the rotary clutch drilling tool. During the normal operation of the rotary clutch drilling tool, the second spline groove on the inner side wall of the lower central shaft housing is disengaged from the second spline on the lower shaft, and the power of the upper drill string cannot be directly transmitted to the driven shaft of the rotary clutch drilling tool. After the rotary clutch drilling tool fails, a ball is dropped down from the wellhead. After the ball reaches the fluid channel inlet of the central shaft of the tool, the fluid channel is blocked, resulting in fluid pressure holding. Under the action of the upper fluid pressure, the central shaft moves downward. The second spline groove of the lower central shaft housing meshes with the second spline on the central shaft, and the power of the upper drill string is directly transmitted to the driven shaft, avoiding the need to pull out the drill string. After the central shaft moves downward for a certain distance, the annular sandwich cavity on the upper central shaft housing is communicated with the fluid channel of the hollow structure of the central shaft, and the drilling fluid above the tool flows downward, and the pressure holding is released, and the central shaft stops moving downward. The sealing end cap assembly is connected to the lower central shaft housing by threads and is used to seal the drilling fluid inside the tool.

[0064] When the emergency transmission tool in this embodiment is used in conjunction with various rotary clutch drilling tools, the internal drive shaft of the rotary clutch drilling tool is connected to the upper drill string, and the driven shaft is connected to the BHA. During its operation, the drive shaft transmits power to the driven shaft to drive the BHA to rotate, and the working mode of the BHA is changed by adjusting the driving torque of the driven shaft. The ball-drop type downhole emergency transmission tool is installed between the rotary clutch drilling tool and the upper drill string to ensure that the power of the upper drill string can still be transmitted to the BHA to complete the directional operation after the rotary clutch drilling tool fails. The emergency transmission tool is used in conjunction with the rotary clutch drilling tool to transmit rotational power from the upper drill string to the BHA (bottom hole assembly) below the rotary clutch drilling tool after the rotary clutch drilling tool fails. During the normal operation of the rotary clutch drilling tool, this 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, the tool is triggered to enter the working mode by dropping a ball into the wellhead to cause the drilling fluid to be blocked at the drilling fluid inlet of the tool. 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, and the directional well engineer can still complete the directional operation through the traditional directional method, effectively avoiding the tripping caused by the failure of the rotary clutch drilling tool and reducing the economic loss.

[0065] This embodiment also provides a downhole emergency transmission method, which is implemented by using the above-mentioned downhole emergency transmission tool. The upper central shaft housing 200 is connected to the upper drill string, the lower central shaft housing 300 is connected to the driven shaft of the rotary clutch drilling tool, and the transmission shaft 400 is connected to the drive shaft of the rotary clutch drilling tool;

[0066] The downhole emergency transmission method includes:

[0067] Under normal working conditions, the rotary clutch drilling tool operates normally. The inner side wall of the upper central shaft housing 200 is in transmission cooperation with the central shaft through the first spline structure 600. The inner side walls of the lower central shaft housing 300 and the central shaft are axially offset with respect to each other's second spline structures. The transmission shaft 400 is in transmission cooperation with the central shaft through the third spline structure 602. The upper drill string transmits power to the drive shaft of the rotary clutch drilling tool through the transmission shaft 400, and the driven shaft of the rotary clutch drilling tool does not receive the power of the upper drill string;

[0068] Under emergency conditions, when the rotary clutch drilling tool fails, the upper opening of the central shaft is blocked to build up pressure. The central shaft moves downward under the action of fluid pressure. The inner side wall of the upper central shaft housing 200 is in driving cooperation with the central shaft through the first spline structure 600, so that the inner side wall of the lower central shaft housing 300 is in driving cooperation with the central shaft through the second spline structure 601. The transmission shaft 400 is in driving cooperation with the central shaft through the third spline structure 602. The power of the upper drill string is transmitted to the drive shaft and the driven shaft of the rotary clutch drilling tool through the central shaft respectively, realizing the emergency drive of the rotary clutch drilling tool.

[0069] Specifically, during the normal operation of the rotary clutch drilling tool, the third spline on the lower side of the lower shaft meshes with the third spline groove on the transmission shaft, and the second spline on the upper side disengages from the second spline groove on the lower central shaft housing. The 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, a ball is dropped into the drill string from the wellhead. When the ball reaches the fluid inlet of the upper central shaft of the tool, it blocks the fluid passage, and pressure builds up above the fluid passage. The upper shaft moves downward under the action of the upper fluid pressure. The second spline on the upper side of the lower shaft meshes with the second spline groove on the lower central shaft housing, and the power of the upper drill string is transmitted to the driven shaft of the rotary clutch drilling tool. After the upper shaft moves downward a certain distance, the annular sandwich cavity of the upper central shaft housing is communicated with the hollow structure of the upper shaft, and the drilling fluid above the tool flows downward, relieving the pressure buildup. The upper shaft stops moving downward, and at the same time, the limit post enters the positioning groove. After the tool is triggered, the power of the upper drill string can be directly transmitted to the driven shaft of the rotary clutch drilling tool. The rotary clutch drilling tool can be equivalent to a drill pipe, ensuring that the directional well engineer can complete the directional operation through the conventional directional drilling method, avoiding tripping, and reducing the economic losses caused by the failure of the rotary clutch drilling tool.

[0070] In the downhole emergency transmission method of this embodiment, after the emergency transmission tool is triggered, the power of the upper drill string can be directly transmitted to the driven shaft of the rotary clutch drilling tool. The rotary clutch drilling tool can be equivalent to a drill pipe, ensuring that the directional well engineer can complete the directional operation through the conventional directional drilling method, avoiding tripping, and reducing the economic losses caused by the failure of the rotary clutch drilling tool.

[0071] In the description of the present invention, it should be understood that the orientation or positional relationship indicated by the terms "center", "longitudinal", "transverse", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", "axial", "radial", "circumferential", etc. is based on the orientation or positional relationship shown in the drawings, and is only for the convenience of describing the present invention and simplifying the description, 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, and therefore should not be construed as a limitation of the present invention.

[0072] In addition, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the quantity of the indicated technical features. Thus, features defined with "first" and "second" may explicitly or implicitly include at least one such feature. In the description of the present invention, the meaning of "a plurality of" is at least two, such as two, three, etc., unless otherwise specifically defined.

[0073] In the present invention, unless otherwise clearly defined and limited, terms such as "mounted", "connected", "coupled", "fixed", etc. should be construed in a broad sense. For example, it may be a fixed connection, a detachable connection, or integrated; it may be a mechanical connection or an electrical connection; it may be directly connected or indirectly connected through an intermediate medium, and it may be the communication inside two elements or the interaction relationship between two elements, unless otherwise clearly limited. 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.

[0074] In the present invention, unless otherwise clearly defined and limited, the first feature being "on" or "under" the second feature may be that the first and second features are in direct contact, or the first and second features are indirectly in contact through an intermediate medium. Moreover, the first feature being "above", "over" and "on top of" the second feature may be that the first feature is directly above or obliquely above the second feature, or merely indicates that the first feature has a higher horizontal height than the second feature. The first feature being "under", "beneath" and "underneath" the second feature may be that the first feature is directly below or obliquely below the second feature, or merely indicates that the first feature has a lower horizontal height than the second feature.

[0075] In the description of this specification, the description with reference to terms such as "one embodiment", "some embodiments", "example", "specific example", or "some examples" means that the specific features, structures, materials, or characteristics described in connection with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic descriptions of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials, or characteristics described can be combined in a suitable manner in any one or more embodiments or examples. In addition, without contradiction, those skilled in the art can combine and combine the different embodiments or examples described in this specification and the features of different embodiments or examples.

[0076] Although the embodiments of the present invention have been shown and described above, it can be understood that the above embodiments are exemplary and should not be construed as limiting the present invention. Those of ordinary skill in the art can make changes, modifications, substitutions, and variations to the above embodiments within the scope of the present invention.

Claims

1. An underground emergency transmission tool, characterized in that, It includes a central shaft, an upper central shaft housing, a lower central shaft housing, a transmission shaft, a spherical pressure-holding member, and a sealing end cover assembly. The upper central shaft housing, the lower central shaft housing, and the transmission shaft are all in a cylindrical structure. The upper central shaft housing is used to connect the upper drill string. The lower central shaft housing is used to connect the driven shaft of the rotary clutch drilling tool. The transmission shaft is used to connect the drive shaft of the rotary clutch drilling tool. The upper central shaft housing is coaxially sleeved outside the upper end of the central shaft. The inner side wall of the upper central shaft housing is in transmission cooperation with the central shaft through a first spline structure. The upper end of the lower central shaft housing is provided with a sealing end cover assembly, and the sealing end cover assembly is hermetically sleeved on the outer side wall of the middle part of the central shaft. The lower central shaft housing is coaxially sleeved outside the lower end of the central shaft. The inner side wall of the lower central shaft housing is in transmission cooperation with the central shaft through a second spline structure or the second spline structures of the inner side wall of the lower central shaft housing and the central shaft are axially offset from each other. The transmission shaft is coaxially sleeved between the lower end of the central shaft and the lower central shaft housing. The transmission shaft is in transmission cooperation with the central shaft through a third spline structure. The central shaft can axially move relative to the upper central shaft housing, the lower central shaft housing, and the transmission shaft. The third spline structure is located below the second spline structure. The sealing end cover assembly is provided with a clamping structure. The outer side wall of the central shaft is provided with a clamping groove. When the central shaft moves to a preset position relative to the sealing end cover assembly, the clamping structure is clamped in the clamping groove. The clamping structure includes a spring and a limiting post. A limiting groove is opened on the inner side wall of the sealing end cover assembly. The limiting post is elastically connected in the limiting groove through a spring. A through channel is opened on the side wall of the sealing end cover assembly. A connecting cover is arranged outside the channel. The connecting cover and the channel enclose to form the limiting groove. One end of the spring is connected to the connecting cover, and the other end of the spring is connected to the limiting post. The outer diameter of the spherical pressure-holding member is smaller than the inner diameter of the upper central shaft housing and not smaller than the inner diameter of the central shaft.

2. The downhole emergency drive tool according to claim 1, characterized in that, The central shaft is of a hollow structure. The central shaft includes an upper shaft section and a lower shaft section. The lower end of the upper shaft section is detachably connected to the upper end of the lower shaft section.

3. The downhole emergency drive tool according to claim 2, wherein The upper end of the upper shaft section is located inside the upper central shaft housing. The lower end of the upper shaft section extends out from the lower end of the upper central shaft housing. A first limiting step is arranged on the inner side wall of the upper central shaft housing. A second limiting step is arranged on the outer side wall of the upper shaft section. The upper end of the upper shaft section is inserted into the upper central shaft housing from the lower end of the upper central shaft housing and the second limiting step abuts against the first limiting step. The first spline structure is located below the first limiting step.

4. The downhole emergency drive tool according to claim 3, wherein, The upper shaft section above the second limiting step is adapted to abut against the upper central shaft housing above the first limiting step. The upper central shaft housing above the first limiting step is provided with an annular sandwich cavity with an open upper end. A first through hole communicating with the annular sandwich cavity is opened on the inner side wall of the upper central shaft housing. A second through hole is opened on the upper shaft section above the second limiting step. Under normal operating conditions, the second through-hole is located above the first through-hole; under emergency conditions, the first through-hole and the second through-hole are in one-to-one correspondence and communication.

5. The downhole emergency drive tool according to claim 1, wherein, The lower end of the central shaft is located above the lower end of the transmission shaft, and the lower end of the transmission shaft is located above the lower end of the lower central shaft housing.

6. A downhole emergency transmission method, characterized in that, It is realized by using the downhole emergency transmission tool according to any one of claims 1 to 5. The upper central shaft housing is connected to the upper drill string, the lower central shaft housing is connected to the driven shaft of the rotary clutch drilling tool, and the transmission shaft is connected to the drive shaft of the rotary clutch drilling tool; The downhole emergency transmission method includes: Under normal operating conditions, the rotary clutch drilling tool operates normally. The inner side wall of the upper central shaft housing and the central shaft are in transmission cooperation through a first spline structure. The inner side walls of the lower central shaft housing and the central shaft are axially offset from each other's second spline structures. The transmission shaft and the central shaft are in transmission cooperation through a third spline structure. The upper drill string transmits power to the drive shaft of the rotary clutch drilling tool through the transmission shaft, and the driven shaft of the rotary clutch drilling tool does not receive the power of the upper drill string; Under emergency conditions, the rotary clutch drilling tool fails, the upper opening of the central shaft is blocked to build pressure, the central shaft moves downward under the action of fluid pressure, the inner side wall of the upper central shaft housing and the central shaft are in transmission cooperation through a first spline structure, so that the inner side wall of the lower central shaft housing and the central shaft are in transmission cooperation through a second spline structure, and the transmission shaft and the central shaft are in transmission cooperation through a third spline structure. The power of the upper drill string is respectively transmitted to the drive shaft and the driven shaft of the rotary clutch drilling tool through the central shaft, realizing the emergency drive of the rotary clutch drilling tool.

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