Flexible inner guide hollow drill rod for low-permeability sandstone uranium mine reservoir and construction method thereof

Abstract

The invention discloses a flexible inner guide hollow drill rod for a low-permeability sandstone uranium mine reservoir. The flexible inner guide hollow drill rod comprises a ball head, a ball socket, an inner guide mechanism, a hollow hydraulic transducer and a drill bit, the ball heads and the ball sockets are arranged in a staggered mode in the drilling direction and connected with each other, the upper ends of the ball heads are in a tip closing-up mode so that the ball heads can be inserted into the lower ends of the ball sockets and can swing relative to the ball sockets under the action of external force, and the upper ends of the ball sockets are inserted into the lower ends of the ball heads and fixedly connected through fasteners so that the lower ball socket and the upper ball head can be assembled. The inner guide mechanism comprises an upper bearing module, a lower bearing module and a steering module located between the two bearing modules, and the upper bearing module is installed on the inner wall of the upper end of one ball socket located on the upper portion in a matched mode and can drive the ball head located on the upper portion to swing. The lower bearing module is installed on the inner wall of the upper end of the ball socket located on the lower portion in a matched mode and can drive the ball head located on the lower portion to swing. The internal guiding of the drill rod is realized through the combined action of the flexible drill rod body and the internal guiding mechanism, and the flexible steering can be realized in the drilling process.

Description

Technical Field

[0001] The invention relates to the technical field of nuclear material mining, and in particular to a flexible inner-guided hollow drill rod for a low-permeability sandstone uranium ore reservoir and a construction method thereof. Background Art

[0002] Uranium ore is an important resource to ensure national energy security and strategic security. Existing uranium ore is mainly stored in low-permeability sandstone, and the reservoir needs to be fractured before in-situ leaching development. Guided drilling of rock reservoirs is the basic condition for fracturing. At present, the fracturing and permeability enhancement of excavating a single vertical shaft has a limited impact range, and the cost of combined fracturing of multiple vertical shafts is high; at the same time, multiple lifting and charging operations during drill pipe drilling not only easily lead to hole collapse, but also greatly affect the timeliness of blasting fracturing. The use of horizontal well blasting fracturing in the oil and gas field is prone to penetrate the top or bottom of the reservoir and cause resource loss. In view of this, it is necessary to develop drilling methods in low-permeability sandstone uranium reservoirs to improve the uniformity of fracturing in low-permeability reservoirs.

[0003] At present, the drill rods in the field of rock drilling are mainly concentrated in the following aspects: 1) Rigid drill rods with extremely small turning angles are suitable for drilling vertical shafts or deep horizontal branch wells with small turning angles. Fixed-angle drilling requires the use of guides or deflectors; 2) Solid flexible drill rods with snap-on or node-connected connections that can achieve torque transmission, with a small turning radius and a solid mechanism, and the guiding method relies on the guide pre-placed in the wellbore. However, the above-mentioned drill rod technologies are generally encountered during implementation: ① Guidance failure caused by the falling or loose fixation of the deflector; ② The guiding angle does not meet the requirements due to insufficient reaction force of the external guiding mechanism when the turning angle is large; ③ Solid drill rods cannot carry out operations such as wellbore washing and explosive loading during drilling, which increases the necessary drilling action before loading explosives. In summary, it is necessary to provide a flexible internally guided hollow drill rod and a construction method for low-permeability sandstone uranium reservoirs to meet the guided excavation of wellbores in low-permeability sandstone uranium reservoirs in deep strata. Summary of the invention

[0004] The main purpose of the present invention is to provide a flexible inner-guided hollow drill rod for low-permeability sandstone uranium ore reservoirs, which can achieve flexible steering during drilling. Correspondingly, the present invention also proposes a construction method for the drill rod.

[0005] The technical solution adopted by the present invention is:

[0006] A flexible inner-guided hollow drill rod for a low-permeability sandstone uranium reservoir, comprising a ball head, a ball socket, an inner guide mechanism, a hollow hydraulic transducer and a drill bit; the ball head and the ball socket are staggered and connected to each other along the drilling direction, the ball head and the ball socket are respectively hollow special-shaped cylindrical structures, wherein the upper end of the ball head is in the form of a pointed end so that it can be inserted into the lower end of the ball socket and can swing relative to the ball socket under the action of an external force, a fixing ring protruding toward the axis is provided in the middle of the ball socket, and fixing hooks extending downward are arranged circumferentially on the fixing ring, the upper end of the ball head is inserted into the lower end of the ball socket from between the inner wall of the lower end of the ball socket and the fixing hook, and the fixing hook hooks the hanging ear provided on the inner wall of the ball head to realize the assembly of the lower ball head and the upper ball socket; the upper end of the ball socket is inserted into the lower end of the ball head and is fixed by a fastener The inner guide mechanism comprises an upper bearing module, a lower bearing module and a steering module located between the two bearing modules, the steering module is used to drive the upper bearing module and the lower bearing module to swing relative to each other to produce an angle difference to achieve steering; the inner guide mechanism is arranged as a whole inside the ball head and the ball socket that are assembled as a whole, wherein the upper bearing module is adapted to be installed with the upper inner wall of the ball socket located above, and can drive the ball head located above to swing; the lower bearing module is adapted to be installed with the upper inner wall of the ball socket located below, and can drive the ball head located below to swing; the upper interface of the hollow hydraulic transducer is fixedly connected to the lowest ball head, and the lower interface is fixedly connected to the drill bit.

[0007] In the above scheme, the steering module includes an upper fixed head, an upper motor support, a connecting sleeve, a lower motor support and a lower fixed head which are arranged in sequence from top to bottom; the upper fixed head is fixedly connected to the upper bearing module, the upper motor support is fixedly connected to the upper fixed head, and an upper motor is arranged in the upper motor support, the lower motor support is fixedly connected to the lower fixed head, and a lower motor is arranged in the lower motor support, and the upper motor and the lower motor are respectively connected to the connecting sleeve through gear transmission; when the upper motor rotates, the connecting sleeve and the lower fixed head are driven to rotate relative to the upper fixed head, and when the lower motor rotates, the connecting sleeve and the upper fixed head are driven to rotate relative to the lower fixed head; the surfaces on which the upper motor support, the lower motor support and the connecting sleeve contact are all inclined surfaces, and the contact surface between the lower motor support and the lower fixed head is an inclined surface; the lower fixed head is fixedly connected to the lower bearing module.

[0008] In the above solution, the inner guide mechanism further includes a fixing cable module located above the upper bearing module, and the signal lines of the upper motor and the lower motor pass through the fixing cable module.

[0009] In the above scheme, the drill pipe also includes an external bevel guide, which includes three annular inflatable structures, namely an inner air cavity, a middle air cavity and an outer air cavity; wherein the inner air cavity is installed on the outer wall of the socket, the center of the middle air cavity is located to the right of the center of the inner air cavity, and the center of the outer air cavity is located below the center of the inner air cavity.

[0010] In the above solution, the drill rod further includes a drill rod transition piece, and the lower end of the drill rod transition piece is fixedly matched with the upper end of the ball socket.

[0011] In the above solution, the outer diameters of the ball head, the ball socket, the hollow hydraulic transducer and the drill pipe transition piece are the same.

[0012] In the above solution, a through liquid channel is provided inside the drill pipe, and the liquid channel is connected to the hollow hydraulic transducer.

[0013] In the above scheme, a plurality of ball head slides are arranged circumferentially on the outer wall of the upper end of the ball head, and a ball socket slideway corresponding to the ball head slide is arranged circumferentially on the inner wall of the lower end of the ball socket, and the ball head slide is inserted into the ball socket slide during assembly; a plurality of ball socket slides are arranged circumferentially on the outer wall of the upper end of the ball socket, and a ball head slideway corresponding to the ball socket slide is arranged circumferentially on the inner wall of the lower end of the ball head, and the ball socket slide is inserted into the ball head slide during assembly.

[0014] In the above scheme, the drill bit includes a drill bit base and cutter teeth, the upper interface of the drill bit base is fixedly matched with the lower interface of the hollow hydraulic transducer; the drill bit base and the bottom of the cutter teeth are fixedly matched.

[0015] Correspondingly, the present invention also proposes a construction method for the above-mentioned low-permeability sandstone uranium reservoir flexible inner guide hollow drill rod, comprising the following steps:

[0016] S1, assembling the flexible inner guide hollow drill rod of the low permeability sandstone uranium reservoir;

[0017] S2, connecting the drill rod transition piece at the upper end of the flexible inner guide hollow drill rod of the low permeability sandstone uranium reservoir to the drilling guide rod, and placing the hollow drill rod into the depth to be guided in the rock borehole through the drilling guide rod;

[0018] S3, filling gas into the outer deflector outside the ball socket through the external cylinder, so that the outer deflector contacts the inner wall of the borehole;

[0019] S4, controlling the steering module of the inner guide mechanism to operate so that an angle difference is generated between the upper bearing module and the lower bearing module;

[0020] S5, applying fluid pressure to the inside of the drilling guide rod, so that the hollow hydraulic transducer drives the drill bit to rotate, and using the downward pressure of the drilling guide rod to apply forward thrust to the hollow drill rod, rotating and crushing the rock to produce a borehole at a certain angle to the rock borehole;

[0021] S6, deflate the external deflector, and after reaching the position where steering is required, repeat the operations of steps S3-S5 to allow the hollow drill rod to drill to the target point;

[0022] S7. Rotate the drill rod in the opposite direction to remove the hollow drill rod.

[0023] The beneficial effects produced by the present invention are:

[0024] 1. The present invention provides a flexible inner-guided hollow drill rod for a low-permeability sandstone uranium reservoir. The inner guidance of the drill rod is realized by the combined action of the flexible drill rod body and the inner guide mechanism, so as to achieve flexible steering during the drilling process; fluid or granular material can be injected into the target reservoir through the internal hollow drill rod, and the drilling, hole washing, blasting and filling actions of the reservoir to be developed can be achieved without lifting the drill, thereby avoiding the energy waste caused by repeated lifting of the drill.

[0025] 2. The external deflector used in the present invention includes three annular inflatable structures, namely an inner air cavity, a middle air cavity and an outer air cavity; wherein the inner air cavity is installed on the outer wall of the ball socket, the center of the middle air cavity is located on the right side of the center of the inner air cavity, and the center of the outer air cavity is located on the lower side of the center of the inner air cavity. The external deflector adopts an asymmetric design, and applies forces in different directions by filling different air cavities with air to adapt to different steering directions. Each air cavity can be inflated separately or in combination. In addition, the air cavity structure of the external deflector can also contact the rock wall to achieve the effect of fixing the hollow drill rod.

[0026] 3. The drill rod of the present invention is designed for guided excavation and charge filling of well bores in low-permeability sandstone uranium reservoirs in deep formations to improve sandstone permeability and uranium mining efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0028] Figure 1 It is a schematic diagram of the overall structure of the flexible inner guide hollow drill rod for low permeability sandstone uranium ore reservoir of the present invention;

[0029] Figure 2 It is an overall cross-sectional view of a flexible inner-guided hollow drill rod for a low-permeability sandstone uranium ore reservoir of the present invention;

[0030] Figure 3 yes Figure 1 The structural schematic diagrams of the ball head of the drill rod at two different angles are shown;

[0031] Figure 4 yes Figure 1 A schematic diagram of the structure of the ball socket of the drill rod shown;

[0032] Figure 5It is a three-dimensional diagram of the assembly state of the ball head and the ball socket;

[0033] Figure 6 It is a cross-sectional view of the ball head and ball socket in the assembled state;

[0034] Figure 7 yes Figure 1 A three-dimensional structural diagram of the inner guide mechanism of the drill pipe shown;

[0035] Figure 8 yes Figure 1 A cross-sectional view of the inner guide mechanism of the drill pipe shown;

[0036] Fig. 9 is a schematic diagram of different steering angles of the inner guide mechanism;

[0037] Fig.10 It is the installation diagram of the inner guide mechanism;

[0038] Fig.11 yes Figure 1 The structural schematic diagram of the external deflector of the drill pipe is shown;

[0039] Fig.12 yes Figure 1 A schematic structural diagram of a drill bit of the drill rod shown;

[0040] Fig.13 yes Figure 1 A schematic structural diagram of a drill pipe transition piece of the drill pipe shown.

[0041] In the figure: 1, ball head; 11, mounting ear; 12, ball head slide; 13, ball head slide;

[0042] 2. ball socket; 21. fixing ring; 22. fixing hook; 23. ball socket slide; 24. ball socket slide;

[0043] 3. External deflector; 31. Inner air cavity; 32. Middle air cavity; 33. Outer air cavity;

[0044] 4. Inner guide mechanism; 41. Upper bearing module; 42. Lower bearing module; 43. Steering module; 431. Upper fixing head; 432. Upper motor support; 433. Connecting sleeve; 434. Lower motor support; 435. Lower fixing head; 436. Upper motor; 437. Lower motor; 44. Fixed cable module; 45. Ball ring; 46. Hollow bearing member;

[0045] 5. Hollow hydraulic transducer;

[0046] 6. drill bit; 61. drill bit base; 62. cutter teeth;

[0047] 7. Drill pipe transition piece. DETAILED DESCRIPTION

[0048] In order to make the purpose, technical solution and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0049] It should be noted that the illustrations provided in the embodiments of the present invention are only used to illustrate the basic concept of the present invention in a schematic manner. Therefore, the drawings only show components related to the present invention rather than being drawn according to the number, shape and size of components in actual implementation. In actual implementation, the type, quantity and proportion of each component may be changed arbitrarily, and the component layout type may also be more complicated.

[0050] In the present invention, it is also necessary to explain that, if the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", etc. appear, the orientation or position relationship indicated is based on the orientation or position relationship shown in the drawings, which is only for the convenience of describing the present application and simplifying the description, and does not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present application. In addition, if the terms "first" and "second" appear, they are only used for description and distinction purposes, and cannot be understood as indicating or implying relative importance.

[0051] like Figure 1-2 As shown, a flexible inner-guide hollow drill rod for low-permeability sandstone uranium reservoir according to a preferred embodiment of the present invention comprises a ball head 1, a ball socket 2, an inner guide mechanism 4, a hollow hydraulic transducer 5 and a drill bit 6.

[0052] like Figure 3-6 As shown, the ball head 1 and the ball socket 2 are staggered and connected to each other along the drilling direction, and the ball head 1 and the ball socket 2 are hollow special-shaped cylindrical structures respectively, wherein the upper end of the ball head 1 is in the form of a pointed end so that it can be inserted into the lower end of the ball socket 2 and can swing relative to the ball socket 2 under the action of external force, and the middle part of the ball socket 2 is provided with a fixing ring 21 protruding toward the axis, and the fixing ring 21 is circumferentially arranged with downwardly extending fixing hooks 22, the upper end of the ball head 1 is inserted into the lower end of the ball socket 2 from between the inner wall of the lower end of the ball socket 2 and the fixing hook 22, and the fixing hook 22 hooks the hanging ear 11 provided on the inner wall of the ball head 1 to realize the assembly of the lower ball head 1 and the upper ball socket 2; the upper end of the ball socket 2 is inserted into the lower end of the ball head 1 and fixedly connected by fasteners (such as pins or bolts) to realize the assembly of the lower ball socket 2 and the upper ball head 1.

[0053] In one embodiment of the present invention, a plurality of ball head slides 12 are arranged circumferentially on the outer wall of the upper end of the ball head 1, and a ball socket slideway 24 corresponding to the ball head slides 12 is arranged circumferentially on the inner wall of the lower end of the ball socket 2, and the ball head slide 12 is inserted into the ball socket slideway 24 during assembly. A certain gap is left between the ball head slide 12 and the ball socket slideway 24 to achieve flexible relative swing.

[0054] In one embodiment of the present invention, a plurality of ball socket slides 23 are arranged circumferentially on the outer wall of the upper end of the ball socket 2, and a ball head slide 13 corresponding to the ball socket slides 23 is arranged circumferentially on the inner wall of the lower end of the ball head 1. During assembly, the ball socket slide 23 is inserted into the ball head slide 13.

[0055] like Figure 7-9 As shown, the inner guide mechanism 4 includes an upper bearing module 41, a lower bearing module 42 and a steering module 43 located between the two bearing modules. The steering module 43 is used to drive the upper bearing module 41 and the lower bearing module 42 to swing relative to each other to generate an angle difference to achieve steering. The steering module 43 includes an upper fixed head 431, an upper motor support 432, a connecting sleeve 433, a lower motor support 434 and a lower fixed head 435 arranged in sequence from top to bottom. The upper fixed head 431 is fixedly connected to the upper bearing module 41, the upper motor support 432 is fixedly connected to the upper fixed head 431, and an upper motor 436 is arranged in the upper motor support 432, the lower motor support 434 is fixedly connected to the lower fixed head 435, and a lower motor 437 is arranged in the lower motor support 434, and the upper motor 436 and the lower motor 437 are respectively connected to the connecting sleeve 433 through gear transmission; when the upper motor 436 rotates, it drives the connecting sleeve 433 and the lower fixed head 435 to rotate relative to the upper fixed head. The head 431 rotates, and when the lower motor 437 rotates, the connecting sleeve 433 and the upper fixed head 431 are driven to rotate relative to the lower fixed head 435; the contact surfaces of the upper motor support 432, the lower motor support 434 and the connecting sleeve 433 are all inclined surfaces, and the contact surface between the lower motor support 434 and the lower fixed head 435 is an inclined surface, so an angle difference can be generated when the lower fixed head 435 and the upper fixed head 431 rotate relative to each other; the lower fixed head 435 is fixedly connected to the lower bearing module 42.

[0056] The inner guide mechanism 4 is integrally arranged inside the ball head 1 and the ball socket 2 which are assembled as one, wherein the upper bearing module 41 is adapted to be installed with the upper inner wall of the ball socket 2 located above, and can drive the ball head 1 located above to swing; the lower bearing module 42 is adapted to be installed with the upper inner wall of the ball socket 2 located below, and can drive the ball head 1 located below to swing. Fig.10As shown, taking the installation of the uppermost inner guide mechanism 4 as an example, the uppermost ball socket 2-1 is fixedly connected to the drill pipe transition piece 7, the ball head 1-1 is inserted into the lower end of the ball socket 2-1, and then the ball socket 2-2 is installed into the lower inner wall of the ball head 1-1, and then the upper bearing module 41 of the inner guide mechanism 4 is installed into the upper inner wall of the ball socket 2-2, and then the ball head 1-2 is installed. At this time, the steering module 43 of the inner guide mechanism 4 is located near the upper inner wall of the ball head 1-2, and then the ball socket 2-3 is installed so that its upper inner wall is assembled with the lower bearing module 42 of the inner guide mechanism 4. In this way, the ball head 1-1 and the ball head 1-2 can respectively swing under the action of the inner guide mechanism 4 to achieve flexible steering. Similarly, the installation of the remaining ball heads 1, ball sockets 2 and inner guide mechanisms 4 is completed in sequence, so that each ball head 1 of the drill pipe of the present invention can swing. It should be noted that in order to clearly see the assembly method of the ball head 1 and the ball socket 2, Figure 1 Only the uppermost inner guide mechanism 4 is shown.

[0057] In one embodiment of the present invention, the upper bearing module 41 and the lower bearing module 42 are both composed of a hollow bearing member 46 and three ball rings 45 mounted thereon.

[0058] In one embodiment of the present invention, the inner guide mechanism 4 further includes a fixing cable module 44 fixed above the upper bearing module 41 , and signal lines of the upper motor 436 and the lower motor 437 pass through the fixing cable module 44 .

[0059] The upper interface of the hollow hydraulic transducer 5 is fixedly connected to the lowermost ball head 1 (the two can be fixed by screws, etc.), and the lower interface is fixedly connected to the drill bit 6.

[0060] like Fig.11 As shown, the flexible inner guiding hollow drill pipe for low permeability sandstone uranium reservoir also includes an outer deflector 3, which includes three annular air-filled structures, namely an inner air cavity 31, a middle air cavity 32 and an outer air cavity 33; wherein the inner air cavity 31 is installed on the outer wall of the ball socket 2, the center of the middle air cavity 32 is located on the right side of the center of the inner air cavity 31, and the center of the outer air cavity 33 is located on the lower side of the center of the inner air cavity 31. The outer deflector 3 adopts an asymmetric design, and applies forces in different directions by filling different air cavities with air to adapt to different steering directions. Each air cavity can be inflated separately or in combination. In addition, the outer deflector 3 adopts an air cavity structure and can also contact the rock wall to achieve the effect of fixing the hollow drill pipe.

[0061] It should be noted that each air cavity of the outer whipstock 3 is connected to the air cylinder on the ground through an air pipe.

[0062] like Fig.12As shown, the flexible inner guide hollow drill pipe for low permeability sandstone uranium reservoir also includes a drill pipe transition piece 7, the lower end of the drill pipe transition piece 7 is fixedly matched with the upper end of the ball socket 2 (the two can be fixed by pins, etc.).

[0063] like Fig.13 As shown, the drill bit 6 includes a drill bit base 61 and a cutter tooth 62 . The upper interface of the drill bit base 61 is fixedly matched with the lower interface of the hollow hydraulic transducer 5 ; the drill bit base 61 and the bottom of the cutter tooth 62 are fixedly matched.

[0064] In one embodiment of the present invention, the outer diameters of the ball head 1, the ball socket 2, the hollow hydraulic transducer 5, and the drill pipe transition piece 7 are the same.

[0065] The construction method of the flexible inner guide hollow drill rod in the low permeability sandstone uranium reservoir comprises the following steps:

[0066] S1. Assemble the flexible inner guide hollow drill pipe for low permeability sandstone uranium reservoir. Specifically, select the number of ball heads 1 and ball sockets 2 according to the drilling depth, and equip the corresponding number of inner guide mechanisms 4 and outer deflectors 3; assemble the ball head 1, ball socket 2 and inner guide mechanism 4 into an integrated structure in the above manner; fix the outer deflector 3 to the outer wall of the ball socket 2; fix the hollow hydraulic transducer 5 connected with the drill bit 6 to the lowermost ball socket 2, and fix the drill pipe transition piece 7 to the uppermost ball socket 2.

[0067] S2, connecting the drill rod transition piece 7 at the upper end of the flexible inner guiding hollow drill rod of the low permeability sandstone uranium reservoir to the drilling guide rod, and placing the hollow drill rod into the depth to be guided in the rock borehole through the drilling guide rod (referring to the position after which the steering is required);

[0068] S3, respectively filling the inner air cavity 31, the middle air cavity 32, and the outer air cavity 33 of the outer deflector 3 outside the ball socket 2 with gas through an external air cylinder, so that the outer deflector 3 contacts the inner wall of the borehole;

[0069] S4, controlling the steering module 43 of the inner guide mechanism 4 to operate so as to generate an angle difference between the upper bearing module 41 and the lower bearing module 42;

[0070] S5. Apply fluid pressure to the inside of the drilling guide rod, so that the hollow hydraulic transducer 5 drives the drill bit 6 to rotate, and use the downward pressure of the drilling guide rod to apply forward thrust to the hollow drill rod, rotating and crushing the rock to produce a borehole at a certain angle to the rock borehole.

[0071] S6, deflate the external deflector 3, and after reaching the position where the turning is required, repeat the operations of steps S3-S5, so that the hollow drill rod is drilled to the target point;

[0072] S7. Rotate the drill rod in the opposite direction to remove the hollow drill rod.

[0073] It should be pointed out that, according to the needs of implementation, the various steps / components described in this application can be split into more steps / components, and two or more steps / components or partial operations of steps / components can be combined into new steps / components to achieve the purpose of the present invention.

[0074] The order of execution of each step in the above embodiment does not mean the order of execution. The execution order of each process should be determined by its function and internal logic, and should not constitute any limitation on the implementation process of the embodiment of the present application.

[0075] It should be understood that those skilled in the art can make improvements or changes based on the above description, and all these improvements and changes should fall within the scope of protection of the appended claims of the present invention.

Claims

1. A flexible inner guide hollow drill rod for low permeability sandstone uranium reservoir, characterized in that: It includes a ball head, a ball socket, an inner guide mechanism, a hollow hydraulic transducer and a drill bit; The ball head and the ball socket are arranged alternately along the drilling direction and connected to each other. The ball head and the ball socket are respectively hollow special-shaped cylindrical structures, wherein the upper end of the ball head is in the form of a pointed end so that it can be inserted into the lower end of the ball socket and can swing relative to the ball socket under the action of external force. A fixing ring protruding toward the axis is provided in the middle of the ball socket, and fixing hooks extending downward are arranged circumferentially on the fixing ring. The upper end of the ball head is inserted into the lower end of the ball socket from between the inner wall of the lower end of the ball socket and the fixing hook, and the fixing hook hooks the hanging ear provided on the inner wall of the ball head to realize the assembly of the lower ball head and the upper ball socket; the upper end of the ball socket is inserted into the lower end of the ball head and fixedly connected through fasteners to realize the assembly of the lower ball socket and the upper ball head; The inner guide mechanism comprises an upper bearing module, a lower bearing module and a steering module located between the two bearing modules, the steering module is used to drive the upper bearing module and the lower bearing module to swing relative to each other to generate an angle difference to achieve steering; the inner guide mechanism is arranged as a whole inside the ball head and the ball socket that are assembled as one, wherein the upper bearing module is adapted to be installed with the upper inner wall of a ball socket located above, and can drive the ball head located above to swing; the lower bearing module is adapted to be installed with the upper inner wall of a ball socket located below, and can drive the ball head located below to swing; The upper interface of the hollow hydraulic transducer is fixedly connected to the lowermost ball head, and the lower interface is fixedly connected to the drill bit.

2. The low-permeability sandstone uranium reservoir flexible inner guide hollow drill rod according to claim 1, characterized in that: The steering module includes an upper fixed head, an upper motor support, a connecting sleeve, a lower motor support and a lower fixed head which are arranged in sequence from top to bottom; the upper fixed head is fixedly connected to the upper bearing module, the upper motor support is fixedly connected to the upper fixed head, and an upper motor is arranged in the upper motor support, the lower motor support is fixedly connected to the lower fixed head, and a lower motor is arranged in the lower motor support, and the upper motor and the lower motor are respectively connected to the connecting sleeve through gear transmission; when the upper motor rotates, the connecting sleeve and the lower fixed head are driven to rotate relative to the upper fixed head, and when the lower motor rotates, the connecting sleeve and the upper fixed head are driven to rotate relative to the lower fixed head; the surfaces on which the upper motor support, the lower motor support and the connecting sleeve contact are all inclined surfaces, and the contact surface between the lower motor support and the lower fixed head is an inclined surface; the lower fixed head is fixedly connected to the lower bearing module.

3. The low-permeability sandstone uranium reservoir flexible inner guide hollow drill rod according to claim 2, characterized in that: The inner guide mechanism further comprises a fixing cable module located above the upper bearing module, and the signal lines of the upper motor and the lower motor pass through the fixing cable module.

4. The low-permeability sandstone uranium reservoir flexible inner guide hollow drill rod according to claim 1, characterized in that: The drill pipe also includes an external bevel guide, which includes three annular inflatable structures, namely an inner air cavity, a middle air cavity and an outer air cavity; wherein the inner air cavity is installed on the outer wall of the socket, the center of the middle air cavity is located to the right of the center of the inner air cavity, and the center of the outer air cavity is located below the center of the inner air cavity.

5. The low-permeability sandstone uranium reservoir flexible inner guide hollow drill rod according to claim 1, characterized in that: The drill rod further comprises a drill rod transition piece, the lower end of which is fixedly matched with the upper end of the ball socket.

6. The low-permeability sandstone uranium reservoir flexible inner guide hollow drill rod according to claim 5, characterized in that: The outer diameters of the ball head, the ball socket, the hollow hydraulic transducer and the drill pipe transition piece are the same.

7. The low-permeability sandstone uranium reservoir flexible inner guide hollow drill rod according to claim 1, characterized in that: A through liquid channel is provided inside the drill rod, and the liquid channel is connected to the hollow hydraulic transducer.

8. The low-permeability sandstone uranium reservoir flexible inner guide hollow drill rod according to claim 1, characterized in that: A plurality of ball head slides are circumferentially arranged on the outer wall of the upper end of the ball head, and a ball socket slideway corresponding to the ball head slide is circumferentially arranged on the inner wall of the lower end of the ball socket, and the ball head slide is inserted into the ball socket slide during assembly; a plurality of ball socket slides are circumferentially arranged on the outer wall of the upper end of the ball socket, and a ball head slideway corresponding to the ball socket slide is circumferentially arranged on the inner wall of the lower end of the ball head, and the ball socket slide is inserted into the ball head slide during assembly.

9. The low-permeability sandstone uranium reservoir flexible inner guide hollow drill rod according to claim 1, characterized in that: The drill bit comprises a drill bit base and cutter teeth. The upper interface of the drill bit base is fixedly matched with the lower interface of the hollow hydraulic transducer; the drill bit base is fixedly matched with the bottom of the cutter teeth.

10. The method for constructing a flexible inner-guided hollow drill rod in a low-permeability sandstone uranium reservoir according to any one of claims 1 to 9, characterized in that: The following steps are involved: S1, assembling the flexible inner guide hollow drill rod of the low permeability sandstone uranium reservoir; S2, connecting the drill rod transition piece at the upper end of the flexible inner guide hollow drill rod of the low permeability sandstone uranium reservoir to the drilling guide rod, and placing the hollow drill rod into the depth to be guided in the rock borehole through the drilling guide rod; S3, filling gas into the outer deflector outside the ball socket through the external cylinder, so that the outer deflector contacts the inner wall of the borehole; S4, controlling the steering module of the inner guide mechanism to operate so that an angle difference is generated between the upper bearing module and the lower bearing module; S5, applying fluid pressure to the inside of the drilling guide rod, so that the hollow hydraulic transducer drives the drill bit to rotate, and using the downward pressure of the drilling guide rod to apply forward thrust to the hollow drill rod, rotating and crushing the rock to produce a borehole at a certain angle to the rock borehole; S6, deflate the external deflector, and after reaching the position where steering is required, repeat the operations of steps S3-S5 to allow the hollow drill rod to drill to the target point; S7. Rotate the drill rod in the opposite direction to remove the hollow drill rod.

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