A hollow-screw motor-based directional drilling electric sealed pressure-maintaining coring drill

Abstract

The application provides a hollow screw motor-based drilling directional electric sealed pressure-maintaining coring drill, which comprises a coring unit, the coring unit comprises an openable and closable drill bit, the drill bit comprises a drill bit body which is internally hollow and open at two axial ends, the drill bit body is connected with a coaxially arranged coring outer tube, and a coring inner tube is coaxially arranged in the coring outer tube. A bottom sealing ball valve and a top sealing ball valve are respectively arranged in the coring inner tube close to the two axial ends, a bottom rack is further arranged on the inner side wall of the drill bit body in the axial direction, the bottom rack is matched with the bottom sealing ball valve, a top rack is further arranged on the inner side wall of the coring outer tube in the axial direction, the top rack is matched with the top sealing ball valve, the movement of the coring inner tube along the bottom rack and the top rack drives the bottom sealing ball valve and the top sealing ball valve to synchronously rotate, and the synchronous opening and closing of the two ends of the coring inner tube are realized. The application can be used to realize the integrated operation mode of drilling direction and sealed coring, and is beneficial to the synchronous improvement of the construction efficiency and the measurement accuracy of the gas content parameter.

Description

Technical Field

[0001] This invention belongs to the field of coal mine geological exploration and safety technology, and relates to pressure-maintaining coring, specifically to a drilling rig with a hollow screw motor and a closed pressure-maintaining coring system. Background Technology

[0002] Gas content is a core parameter for mine gas disaster prevention and coalbed methane development, and its measurement accuracy is closely related to the degree to which the in-situ state of the coal core is preserved. Because gas escapes after the coal core is exposed, leading to significantly lower measured values, industry standards clearly require that the time from exposure to sealing of the coal core must not exceed 5 minutes. While current underground sealed coring technology in coal mines can achieve pressure-maintaining coring, it still has the following key drawbacks:

[0003] First, the control method is inefficient: the pressure-holding and sealing mechanism mostly relies on mechanical triggering or high-pressure water drive, which makes the operation process cumbersome and complicated, and inefficient. Second, the operation cannot be repeated: the normally open sealing structure is generally used, and only one sealing operation can be completed in a single drilling. During the drilling process, the core sampling channel is very easy to be blocked or accidentally closed. Third, it relies on auxiliary materials: sealing requires the use of special drill pipes to deliver sealing balls, which increases material costs. Fourth, the separation between directional drilling and coring: directional drilling and pressure-maintaining coring operations need to be carried out in separate steps, resulting in frequent tripping and tripping operations, which significantly prolongs the exposure time of the coal core. Summary of the Invention

[0004] To address the shortcomings of existing technologies, the present invention aims to provide a drilling directional electric sealed pressure-maintaining coring tool based on a hollow screw motor, thereby solving the technical problem in existing technologies where it is difficult to simultaneously improve the accuracy of measurement results and the efficiency of work when measuring gas content in coal mines.

[0005] To solve the above-mentioned technical problems, the present invention adopts the following technical solution.

[0006] A hollow screw motor-based directional electric closed pressure-maintaining coring tool includes a coring unit. The coring unit includes an openable and closable drill bit. The drill bit includes a drill bit body that is hollow inside and open at both ends in the axial direction. The inner side wall of the upper axial section of the drill bit body is connected to the outer side wall of the lower axial section of a coring outer tube that is coaxially arranged and open at both ends in the axial direction. The coring outer tube also has a coring inner tube that is coaxially arranged inside, which is open at the bottom in the axial direction and closed at the top in the axial direction.

[0007] The inner core tube is equipped with a bottom sealing ball valve and a top sealing ball valve radially installed near both ends of the axial direction. The drill bit body is also provided with a bottom rack along the axial direction on the inner wall near the top of the axial direction. The bottom rack cooperates with the bottom sealing ball valve. The outer core tube is also provided with a top rack along the axial direction on the inner wall near the top of the axial direction. The top rack cooperates with the top sealing ball valve. The axial movement of the inner core tube along the bottom rack and the top rack drives the synchronous rotation of the bottom sealing ball valve and the top sealing ball valve, thereby realizing the synchronous opening or closing of both ends of the inner core tube.

[0008] It also includes a hollow screw motor, which includes an electric drive assembly that is connected to the core-collecting inner tube and drives the core-collecting inner tube to move axially.

[0009] The present invention also has the following technical features.

[0010] Specifically, the working modes of the drilling tool include full-face directional drilling mode, core drilling mode, and in-situ electric closed pressure maintenance mode.

[0011] The initial working mode of the drill bit is full-face directional drilling mode. In full-face directional drilling mode, the bottom sealing ball valve and the top sealing ball valve are closed, the openable drill bit is closed, and there is no coal core in the core sifter.

[0012] The drill bit is in the core drilling mode. The bottom sealing ball valve and the top sealing ball valve are open, the drill bit can be opened and closed, and the coal core gradually enters the core drilling tube.

[0013] The drilling tool is in the in-situ electric closed pressure-holding mode, with the bottom sealing ball valve and the top sealing ball valve closed, and the core tube containing the coal core after core taking.

[0014] Specifically, a radially penetrating bottom rotating shaft through hole is provided on the side wall of the core-taking inner tube near the axial bottom. One end of the rotating shaft of the bottom sealing ball valve extends out of the core-taking inner tube through the bottom rotating shaft through hole. A bottom gear is also coaxially mounted on one end of the rotating shaft of the bottom sealing ball valve, and the bottom gear meshes with the bottom rack.

[0015] The inner core tube is provided with a radially penetrating bottom pin through hole on the side wall near the axial bottom. A bottom limiting pin is also coaxially provided on the other end of the rotating shaft of the bottom sealing ball valve. The bottom limiting pin extends out of the inner core tube through the bottom pin through hole. The drill bit body is provided with a bottom sliding groove along the axial direction on the inner side wall near the axial top. The bottom limiting pin is slidably installed in the bottom sliding groove to achieve circumferential limiting of the inner core tube relative to the outer core tube.

[0016] The inner tube of the core is provided with a radially penetrating top rotating shaft through hole on the side wall near the axial top. One end of the rotating shaft of the top sealing ball valve extends out of the inner tube of the core through the top rotating shaft through hole. A top gear is also coaxially mounted on one end of the rotating shaft of the top sealing ball valve, and the top gear meshes with the top rack.

[0017] The inner core tube has a radially penetrating top pin through hole on its side wall near the axial top. A top limiting pin is also coaxially provided on the other end of the rotating shaft of the top sealing ball valve. The top limiting pin extends out of the inner core tube through the top pin through hole. The outer core tube has a top sliding groove along the axial direction on its inner side wall near the axial top. The top limiting pin is slidably installed in the top sliding groove to achieve circumferential limiting of the inner core tube relative to the outer core tube.

[0018] Specifically, a fixed cutter wing is fixedly installed on the outer periphery of the axial bottom of the drill bit body, and a pair of rotatable cutter wings are hinged to the axial bottom of the drill bit body. The rotatable cutter wings are coaxially arranged inside the fixed cutter wings. The axial bottom of the axially moving core tube pushes the rotatable cutter wings to open, thereby opening the axial bottom of the drill bit.

[0019] Specifically, the axial top end face of the core-taking inner tube is also provided with a desorption port that penetrates the end face.

[0020] Specifically, the top of the hollow screw motor is also provided with a drilling measurement sub, a cable-guided drill rod, and a cable-guided water pipe connected in sequence from bottom to top. The hollow screw motor is also connected to the drilling measurement sub, and the cable-guided water pipe is also connected to the wellhead controller installed at the wellhead, thereby realizing the transmission of electrical signals throughout the device.

[0021] Specifically, the hollow screw motor also includes, from bottom to top along the drilling direction, a drive shaft assembly, a universal joint assembly, and a motor assembly connected in sequence. The drive shaft assembly, universal joint assembly, and motor assembly are all hollow inside and open at both ends along the axial direction.

[0022] The electric drive assembly includes a hollow drive section housing that is open at both axial ends. The drive section housing is located at the bottom of the drive shaft assembly. The outer side wall of the upper axial section of the drive section housing is connected to the inner side wall of the lower section of the drive shaft assembly, and the outer side wall of the lower axial section of the drive section housing is connected to the inner side wall of the upper axial section of the core-retrieving outer tube. A servo electric cylinder is also coaxially installed inside the drive section housing. The servo electric cylinder is connected to the core-retrieving inner tube and drives the core-retrieving inner tube to move axially.

[0023] Specifically, the servo electric cylinder includes an electric cylinder body, which is coaxially mounted in the drive section housing near the bottom of the axial direction via a first positioning ring, and coaxially mounted in the drive section housing near the top of the axial direction via a first locking ring.

[0024] The electric cylinder body has a piston rod coaxially mounted on its axial bottom; the inner tube has an inner tube connecting rod coaxially mounted on its outer side of the top end face, and the top of the inner tube connecting rod is connected to the bottom of the coaxially mounted electric cylinder piston rod.

[0025] The electric cylinder body has an electric cylinder drive block coaxially mounted on its top axis, which drives the electric cylinder piston rod to move axially. The cavity connecting the transmission shaft assembly, the universal joint assembly, and the motor assembly is also equipped with a flexible connecting rod, a battery, and a bottom wireless communication module, which are connected in sequence from bottom to top. The bottom wireless communication module is also connected to the electric cylinder drive block at the bottom, thereby realizing the transmission of electrical signals in the hollow screw motor.

[0026] Specifically, the measurement while drilling sub includes a hollow outer tube with open ends in the axial direction. A shorting inner tube is coaxially arranged inside the outer tube. The shorting inner tube is installed in the outer tube near the bottom in the axial direction by a second positioning ring, and the shorting inner tube is installed in the outer tube near the top in the axial direction by a second locking ring.

[0027] The short-circuit inner tube is equipped with a top wireless communication module, a magnetic sensor module, an acceleration sensor module, a control module, and a wired communication module installed sequentially from bottom to top along the axial direction. The top wireless communication module is connected to the bottom wireless communication module via radio electromagnetic waves, and the wired communication module is connected to the top cable drill rod via a wire.

[0028] Specifically, the outer wall of the axial lower section of the short outer tube is connected to the inner wall of the upper section of the hollow screw motor, and the inner wall of the axial upper section of the short outer tube is connected to the outer wall of the axial lower section of the cable drill rod.

[0029] The aforementioned cable drill rod is also connected to a cable water pipe that is coaxially arranged at the top.

[0030] Compared with the prior art, the present invention has the following technical effects.

[0031] (I) The device in this invention achieves in-situ, efficient and precise electric sealing at the bottom of the borehole, which fundamentally ensures the measurement accuracy of gas content parameters. The device is driven by a wired and wireless collaborative communication architecture to achieve sealing. After core sampling, it can quickly and reliably seal the coal core, keeping the time from exposure to sealing within 3 minutes. This suppresses gas escape from the source and reduces the gas content measurement error by more than 20%, providing highly reliable data support for disaster prevention and resource assessment.

[0032] (II) The device in this invention has repeatable and highly reliable electric sealing capability, which significantly improves the success rate and economy of the operation. By eliminating disposable mechanical or ball-throwing mechanisms, it can be used to realize remote electric control of the opening and closing of the bottom sealing ball valve and the top sealing ball valve, effectively avoiding the risk of blockage and accidental closure in the drilling process of traditional normally open structures, increasing the single core success rate to more than 95%, and significantly improving the level of intensification and economic benefits of exploration operations.

[0033] (III) The device in this invention establishes an electronic control mode without auxiliary consumables, which simplifies the process and reduces the overall cost. By eliminating materials such as sealing balls, the sealing action at the bottom of the hole can be accurately triggered by the electrical signal at the orifice, which not only saves the cost of a single operation, but also fundamentally eliminates the sealing failure caused by "inaccurate ball throwing", which can simultaneously enhance the reliability and economy of the device during operation.

[0034] (IV) The device in this invention can be used to realize the integrated operation mode of long-distance directional drilling and fixed-point in-situ pressure-maintaining coring in coal seams, which is conducive to the simultaneous improvement of construction efficiency and safety. By integrating the hollow screw motor and the coring unit, directional drilling and pressure-maintaining coring are combined into one, forming a "one-trip drilling" well completion operation mode, eliminating the cumbersome process of "directional drilling → tripping out → changing coring tools → going down again" in the traditional process, shortening the overall construction cycle, and avoiding the operational risks of wellbore instability and tool drop caused by multiple tripping out from the source. Attached Figure Description

[0035] Figure 1 This is a schematic diagram of the overall structure of the device in an embodiment of the present invention.

[0036] Figure 2 This is a schematic diagram of the coring unit in the device of this embodiment of the invention during full-section drilling.

[0037] Figure 3 This is a schematic diagram of the core-taking unit in the device of this embodiment of the invention during core drilling.

[0038] Figure 4 This is a schematic diagram of the hollow screw motor in the device of an embodiment of the present invention.

[0039] Figure 5 This is a schematic diagram of the electric drive assembly in the device of an embodiment of the present invention.

[0040] Figure 6 This is a schematic diagram of the structure of the measurement while drilling sub in the device of this embodiment of the invention.

[0041] The meanings of the labels in the diagram are as follows: 1-Coring unit, 2-Hollow screw motor, 3-Measuring while drilling sub, 4-Cable drill pipe, 5-Cable water supply, 6-Borehead controller.

[0042] 101-Drill bit, 102-Outer core tube, 103-Inner core tube, 104-Bottom sealing ball valve, 105-Top sealing ball valve, 106-Top rack, 107-Desorption port, 108-Bottom shaft through hole, 109-Bottom pin through hole, 110-Bottom limiting pin, 111-Top shaft through hole, 112-Top pin through hole, 113-Top limiting pin, 114-Top slide groove, 115-Inner tube connecting rod, 116-Bottom gear, 117-Top gear, 118-Coal core inlet.

[0043] 201-Electric drive assembly, 202-Drive shaft assembly, 203-Universal shaft assembly, 204-Motor assembly.

[0044] 301 - Short section outer tube, 302 - Shorted inner tube, 303 - Second positioning ring, 304 - Second locking ring, 305 - Top wireless communication module, 306 - Magnetic sensor module, 307 - Accelerometer sensor module, 308 - Control module, 309 - Wired communication module.

[0045] 10101-Drill bit body, 10102-Bottom rack, 10103-Bottom groove, 10104-Fixed cutter blade, 10105-Rotating cutter blade.

[0046] 20101-Drive short section housing, 20102-Servo electric cylinder, 20103-First positioning ring, 20104-First locking ring, 20105-Flexible connecting rod, 20106-Battery, 20107-Bottom wireless communication module.

[0047] 2010201 - Electric cylinder body, 2010202 - Electric cylinder piston rod, 2010203 - Electric cylinder drive block.

[0048] The specific content of the present invention will be further described in detail below with reference to the embodiments. Detailed Implementation

[0049] It should be noted that, unless otherwise specified, all the equipment, methods, components and materials in this invention are commonly used in the art in the prior art. For example, the gas desorber is a known gas desorber, the method for detecting the gas content in the coal core is a known method, the second positioning ring is a known positioning ring, the second locking ring is a known locking ring, the coal core is a known coal core, and the drilling fluid is a known drilling fluid.

[0050] Following the above technical solution, specific embodiments of the present invention are given below. It should be noted that the present invention is not limited to the following specific embodiments, and all equivalent modifications made on the basis of the technical solution of the present invention fall within the protection scope of the present invention.

[0051] Example: This embodiment presents a drilling-while-drilling directional electric sealed pressure-maintaining coring tool based on a hollow screw motor, such as... Figures 1 to 3 As shown, it includes a core sampling unit 1, which includes an openable and closable drill bit 101. The drill bit 101 includes a drill bit body 10101 that is hollow inside and open at both ends in the axial direction. The inner side wall of the upper axial section of the drill bit body 10101 is connected to the outer side wall of the lower axial section of the core sampling outer tube 102 that is coaxially arranged and open at both ends in the axial direction. The core sampling outer tube 102 also has a coaxially arranged inner core sampling tube 103 that is open at the bottom in the axial direction and closed at the top in the axial direction.

[0052] like Figures 2 to 3 As shown, a bottom sealing ball valve 104 and a top sealing ball valve 105 are respectively installed radially near both ends of the inner core tube 103. A bottom rack 10102 is also provided axially on the inner wall of the drill bit body 10101 near the top of the axial direction. The bottom rack 10102 cooperates with the bottom sealing ball valve 104. A top rack 106 is also provided axially on the inner wall of the outer core tube 102 near the top of the axial direction. The top rack 106 cooperates with the top sealing ball valve 105. The axial movement of the inner core tube 103 along the bottom rack 10102 and the top rack 106 drives the bottom sealing ball valve 104 and the top sealing ball valve 105 to rotate synchronously, thereby realizing the synchronous opening or closing of both ends of the inner core tube 103.

[0053] It also includes a hollow screw motor 2, which includes an electric drive assembly 201. The electric drive assembly 201 is connected to the core-collecting inner tube 103 and drives the core-collecting inner tube 103 to move axially.

[0054] As a preferred embodiment, the working modes of the drilling tool include full-face directional drilling mode, core drilling mode, and in-situ electric closed pressure holding mode.

[0055] The initial working mode of the drill bit is full-face directional drilling mode. In full-face directional drilling mode, the bottom sealing ball valve 104 and the top sealing ball valve 105 are closed, the openable drill bit 101 is closed, and there is no coal core in the core tube 103.

[0056] When the drilling tool is in the core drilling mode, the bottom sealing ball valve 104 and the top sealing ball valve 105 are opened, the openable drill bit 101 is opened, and the coal core gradually enters the core drilling inner tube 103.

[0057] The drilling tool is in the in-situ electric closed pressure-holding mode, with the bottom sealing ball valve 104 and the top sealing ball valve 105 closed, and the core tube 103 contains the coal core after core taking.

[0058] As a preferred embodiment of this invention, such as Figures 2 to 3 As shown, a radially penetrating bottom shaft through hole 108 is also provided on the side wall of the core-retrieving inner tube 103 near the axial bottom. One end of the rotating shaft of the bottom sealing ball valve 104 extends out of the core-retrieving inner tube 103 through the bottom shaft through hole 108. A bottom gear 116 is also coaxially mounted on one end of the rotating shaft of the bottom sealing ball valve 104. The bottom gear 116 meshes with the bottom rack 10102.

[0059] The inner core tube 103 is provided with a radially penetrating bottom pin through hole 109 on the side wall near the bottom of the axial direction. The bottom limiting pin 110 is also coaxially provided on the other end of the rotating shaft of the bottom sealing ball valve 104. The bottom limiting pin 110 extends out of the inner core tube 103 through the bottom pin through hole 109. The drill bit body 10101 is provided with a bottom sliding groove 10103 along the axial direction on the inner side wall near the top of the axial direction. The bottom limiting pin 110 is slidably installed in the bottom sliding groove 10103 to achieve circumferential limiting of the inner core tube 103 relative to the outer core tube 102.

[0060] like Figures 2 to 3 As shown, a radially penetrating top rotating shaft through hole 111 is also provided on the side wall of the core-retrieving inner tube 103 near the axial top. One end of the rotating shaft of the top sealing ball valve 105 extends out of the core-retrieving inner tube 103 through the top rotating shaft through hole 111. A top gear 117 is also coaxially mounted on one end of the rotating shaft of the top sealing ball valve 105. The top gear 117 meshes with the top rack 106.

[0061] The inner tube 103 near the axial top is provided with a radially penetrating top pin through hole 112. The other end of the rotating shaft of the top sealing ball valve 105 is also coaxially provided with a top limiting pin 113. The top limiting pin 113 extends out of the inner tube 103 through the top pin through hole 112. The inner side wall of the outer tube 102 near the axial top is also provided with a top sliding groove 114 along the axial direction. The top limiting pin 113 is slidably installed in the top sliding groove 114 to realize the circumferential limiting of the inner tube 103 relative to the outer tube 102.

[0062] In this embodiment, the bottom limiting pin 110 and the top limiting pin 113 ensure that the core-retrieving inner tube 103 moves axially, and at the same time can play the role of straightening the core-retrieving inner tube 103.

[0063] As a preferred embodiment of this invention, such as Figures 2 to 3As shown, a fixed cutter 10104 is also fixedly installed on the outer periphery of the axial bottom of the drill bit body 10101 along the circumferential direction. A pair of rotatable cutter wings 10105 are also hinged to the axial bottom of the drill bit body 10101. The rotatable cutter wings 10105 are coaxially arranged inside the fixed cutter wings 10104. The axial bottom of the axially moving core tube 103 pushes the rotatable cutter wings 10105 to open, thereby opening the axial bottom of the drill bit 101.

[0064] In this embodiment, the electric drive assembly 201 of the hollow screw motor 2 drives the core-taking inner tube 103 to move axially downwards, which in turn controls the synchronous opening of the bottom sealing ball valve 104 and the top sealing ball valve 105, as well as the opening of the central channel of the drill bit 101. This allows for the opening of the rotating cutter blade 10105, thereby enabling the switching between full-face directional drilling and core drilling modes. In this embodiment, both the bottom sealing ball valve 104 and the top sealing ball valve 105 are commonly used sealing ball valves known in the art.

[0065] As a preferred embodiment of this invention, such as Figures 2 to 3 As shown, a desorption port 107 that penetrates the end face is also provided on the axial top end face of the core-taking tube 103.

[0066] As a preferred embodiment of this invention, such as Figure 1 As shown, the top of the hollow screw motor 2 is also provided with a drilling measurement sub 3, a cable-guided drill rod 4, and a cable-guided water pipe 5 connected in sequence from bottom to top. The hollow screw motor 2 is also connected to the drilling measurement sub 3, and the cable-guided water pipe 5 is also connected to the wellhead controller 6 installed at the wellhead, thereby realizing the transmission of electrical signals throughout the device.

[0067] In this embodiment, the port at the bottom of the core tube 103 is the core inlet 118.

[0068] In this embodiment, the coring unit 1, hollow screw motor 2, measurement-while-drilling (MSWD) sub 3, cable-guided drill pipe 4, cable-guided water supply 5, and wellhead controller 6 are arranged sequentially from the bottom of the hole to the wellhead. The coring unit 1, hollow screw motor 2, MSWD sub 3, cable-guided drill pipe 4, and cable-guided water supply 5 are sequentially threaded together, and the cable-guided water supply 5 is connected to the wellhead controller 6 via a cable. In this embodiment, the cable-guided drill pipe 4 is a commonly used type known in the art, the cable-guided water supply 5 is a commonly used type known in the art, and the wellhead controller 6 is a commonly used type known in the art.

[0069] In this embodiment, the core sampling unit 1 is used to drill into the coal seam to obtain coal cores. The hollow screw motor 2 can drive the drill bit 101 to rotate and crush the coal body to achieve drilling, and can also drive the core sampling unit 1 to achieve switching between core drilling and full-face drilling. The measurement while drilling sub 3 is used to measure the borehole trajectory parameters and also serves as a signal hub, transmitting and receiving signals to the hollow screw motor 2 through the radio electromagnetic wave transmission channel between the top wireless communication module 305 and the bottom wireless communication module 20107, thus realizing wireless signal transmission between the electric drive assembly 201 and the measurement while drilling sub 3. The borehole controller 6 establishes a wired signal transmission channel with the wired communication module 309 of the measurement while drilling sub 3 through a wired signal transmission channel composed of the cable drill rod 4 and the cable water pipe 5. Through the coordination of the above wireless and wired transmission methods, a stable and reliable connection is finally established between the borehole controller 6, the measurement while drilling sub 3, and the electric drive assembly 201.

[0070] As a preferred embodiment of this invention, such as Figure 4 As shown, the hollow screw motor 2 also includes a drive shaft assembly 202, a universal joint assembly 203 and a motor assembly 204 connected in sequence from bottom to top along the drilling direction. The drive shaft assembly 202, the universal joint assembly 203 and the motor assembly 204 are all hollow inside and open at both ends in the axial direction.

[0071] The electric drive assembly 201 includes a hollow drive section housing 20101 that is open at both axial ends. The drive section housing 20101 is located at the bottom of the drive shaft assembly 202. The outer side wall of the upper axial section of the drive section housing 20101 is connected to the inner side wall of the lower section of the drive shaft assembly 202, and the outer side wall of the lower axial section of the drive section housing 20101 is connected to the inner side wall of the upper axial section of the core-retrieving outer tube 102. A servo electric cylinder 20102 is also coaxially mounted inside the drive section housing 20101. The servo electric cylinder 20102 is connected to the core-retrieving inner tube 103 and drives the core-retrieving inner tube 103 to move axially.

[0072] In this embodiment, the drive shaft assembly 202, the universal joint assembly 203, and the motor assembly 204 all adopt drive shaft assemblies, universal joint assemblies, and motor assemblies commonly known in the art.

[0073] As a preferred embodiment of this invention, such as Figures 4 to 5 As shown, the servo electric cylinder 20102 includes an electric cylinder body 2010201. The electric cylinder body 2010201 is coaxially mounted in the drive section housing 20101 near the bottom of the axial direction via a first positioning ring 20103. The electric cylinder body 2010201 is coaxially mounted in the drive section housing 20101 near the top of the axial direction via a first locking ring 20104.

[0074] The bottom of the electric cylinder body 2010201 is coaxially provided with an electric cylinder piston rod 2010202; the outer side of the top end face of the core tube 103 is also coaxially and integrally provided with an inner tube connecting rod 115, the top of the inner tube connecting rod 115 is connected to the bottom of the coaxially arranged electric cylinder piston rod 2010202.

[0075] An electric cylinder drive block 2010203 is coaxially mounted on the top of the electric cylinder body 2010201. The electric cylinder drive block 2010203 drives the electric cylinder piston rod 2010202 to move axially. In the cavity where the transmission shaft assembly 202, the universal joint assembly 203 and the motor assembly 204 are connected, a flexible connecting rod 20105, a battery 20106 and a bottom wireless communication module 20107 are installed sequentially from bottom to top. The bottom wireless communication module 20107 is also connected to the electric cylinder drive block 2010203 arranged at the bottom, thereby realizing the transmission of electrical signals in the hollow screw motor 2.

[0076] In this embodiment, the internal through holes of the drive shaft assembly 202, the universal joint assembly 203, and the motor assembly 204 are connected to form a continuous central channel of equal diameter; the flexible connecting rod 20105 is equipped with a communication cable, which connects the battery 20106 and the servo cylinder 20102, forming a power supply and signal transmission channel at the bottom of the electric drive assembly 201.

[0077] In this embodiment, the flexible connecting rod 20105 adopts a flexible connecting rod commonly known in the art, the battery 20106 adopts a battery commonly known in the art, and the bottom wireless communication module 20107 adopts a wireless communication module commonly known in the art.

[0078] As a preferred embodiment of this invention, such as Figure 6 As shown, the measurement while drilling sub 3 includes a hollow outer tube 301 with open ends in the axial direction. A short-connecting inner tube 302 is coaxially arranged inside the outer tube 301. The short-connecting inner tube 302 is installed in the outer tube 301 near the bottom in the axial direction via a second positioning ring 303, and the short-connecting inner tube 302 is installed in the outer tube 301 near the top in the axial direction via a second locking ring 304.

[0079] Inside the short-circuit inner tube 302, from bottom to top, are installed a top wireless communication module 305, a magnetic sensor module 306, an acceleration sensor module 307, a control module 308, and a wired communication module 309 connected in sequence. The top wireless communication module 305 is connected to the bottom wireless communication module 20107 located at the bottom via radio electromagnetic waves, and the wired communication module 309 is wired to the top cable drill rod 4.

[0080] In this embodiment, the top wireless communication module 305, magnetic sensor module 306, acceleration sensor module 307, control module 308, and wired communication module 309 all adopt modules commonly known in the art.

[0081] As a preferred embodiment, the outer wall of the axially lower section of the short outer tube 301 is connected to the inner wall of the upper section of the hollow screw motor 2, and the inner wall of the axially upper section of the short outer tube 301 is connected to the outer wall of the axially lower section of the cable drill rod 4.

[0082] The cable-connecting drill rod 4 is also connected to the cable-connecting water pipe 5, which is coaxially arranged at the top of the axial direction.

[0083] When the device in this embodiment is used, it specifically includes the following steps: Step 1, Preparation and Drilling: Connect each component of the drilling tool in sequence to establish a communication link between the orifice controller 6 and the downhole measurement-while-drilling sub 3 and electric drive assembly 201; lower the drilling tool to the predetermined position.

[0084] Step 2, Full-face directional drilling mode: Orifice Command: The operator selects the "directional drilling" mode on the orifice controller 6 and sends the command.

[0085] Signal transmission: The command is transmitted through the wired channel of the cable drill pipe 4 to the measurement while drilling section 3, and then sent through the top wireless communication module 305 to the bottom wireless communication module 20107 of the hollow screw motor 2.

[0086] Electric drive execution: The electric cylinder drive block 2010203 controls the servo electric cylinder 20102 to retract, and the electric cylinder piston rod 2010202 pulls the inner tube connecting rod 115, thereby driving the core-taking inner tube 103 to move axially to the top.

[0087] Mechanism operation: During the upward movement of the core tube 103, the bottom sealing ball valve 104 and the top sealing ball valve 105 are simultaneously closed via the bottom rack 10102 and the top rack 106; at this time, the rotatable blade 10105 of the drill bit 101 is closed.

[0088] Status Confirmation: The drill string enters full-face drilling mode, and the drilling fluid drives the hollow screw motor 2 to rotate the drill bit 101 to perform full-face directional drilling; the measurement-while-drilling sub 3 monitors the directional drilling trajectory in real time.

[0089] Step 3, Core drilling mode: Switching timing: After full-section directional drilling reaches the predetermined coring point.

[0090] Orifice command: The operator sends the "take core" command.

[0091] Electric drive execution: The electric cylinder drive block 2010203 controls the extension of the servo electric cylinder 20102, and the electric cylinder piston rod 2010202 pushes the inner tube connecting rod 115, which drives the core-taking inner tube 103 to move axially to the bottom.

[0092] Mechanism operation: When the core-taking inner tube 103 moves downward, it drives the bottom sealing ball valve 104 and the top sealing ball valve 105 to open simultaneously through the bottom rack 10102 and the top rack 106; the rotatable blade 10105 of the drill bit 101 is pushed open by the downward movement of the core-taking inner tube 103, forming a coal core entry channel.

[0093] Status Confirmation: The drill string has entered the core drilling mode and is performing core drilling; the coal core enters the core drilling inner tube 103 through the open drill bit 101 and the coal core inlet 118.

[0094] Step 4, in-situ electric sealing and pressure maintenance: Switching timing: Perform this operation immediately at the bottom of the hole after completing the predetermined core advance.

[0095] Orifice command: The operator sends a "close" command.

[0096] Electric drive execution: The electric cylinder drive block 2010203 controls the servo electric cylinder 20102 to retract again, and the electric cylinder piston rod 2010202 pulls the inner tube connecting rod 115, which drives the core-taking inner tube 103 to move upward.

[0097] Mechanism action: After the core-taking inner tube 103 moves upward, the bottom sealing ball valve 104 and the top sealing ball valve 105 quickly close, completing the core cutting and keeping the core in a sealed and pressure-maintaining state within the core-taking inner tube 103. This sealing action is completed in place at the bottom of the borehole before the core is lifted to the borehole opening, minimizing the time the core is exposed to a low-pressure environment.

[0098] Step 5, Drilling and Gas Detection: The drilling fluid is stopped, meaning the drill bit 101 stops rotating. The entire drill string is pulled out of the borehole, and the core unit 1 is removed. The gas desorber is then directly connected to the desorption port 107 to measure the gas content parameters of the coal core inside the core tube 103.

[0099] In this embodiment, the instructions in steps two, three, and four are transmitted to the measurement-while-drilling section 3 via the wired channels of the cable drill pipe 4 and the cable water pipe 5, and then relayed wirelessly to the electric drive assembly 201 of the hollow screw motor 2 for execution.

[0100] In this embodiment, in a single borehole, the coring operation of multiple borehole segments is achieved by repeatedly executing steps one to five.

Claims

1. A directional, electrically controlled, closed-loop, pressure-maintaining coring tool based on a hollow screw motor, comprising a coring unit (1), characterized in that, The core-taking unit (1) includes an openable and closable drill bit (101). The drill bit (101) includes a drill bit body (10101) that is hollow inside and open at both ends in the axial direction. The inner side wall of the upper axial section of the drill bit body (10101) is connected to the outer side wall of the lower axial section of the core-taking outer tube (102) that is coaxially arranged and open at both ends in the axial direction. The core-taking outer tube (102) also has a core-taking inner tube (103) that is coaxially arranged inside, which is open at the bottom in the axial direction and closed at the top in the axial direction. The inner core tube (103) is equipped with a bottom sealing ball valve (104) and a top sealing ball valve (105) respectively, which are installed radially near the two ends of the axial direction. The drill bit body (10101) is also provided with a bottom rack (10102) along the axial direction on the inner wall near the top of the axial direction. The bottom rack (10102) cooperates with the bottom sealing ball valve (104). The outer core tube (102) is also provided with a top rack (106) along the axial direction on the inner wall near the top of the axial direction. The top rack (106) cooperates with the top sealing ball valve (105). The inner core tube (103) moves along the axial direction of the bottom rack (10102) and the top rack (106) to drive the bottom sealing ball valve (104) and the top sealing ball valve (105) to rotate synchronously, thereby realizing the synchronous opening or closing of both ends of the inner core tube (103). It also includes a hollow screw motor (2), which includes an electric drive assembly (201) that is connected to the core-collecting inner tube (103) and drives the core-collecting inner tube (103) to move axially.

2. The drilling-while-drilling directional electric sealed pressure-maintaining coring tool based on a hollow screw motor as described in claim 1, characterized in that, The drilling tools described include full-face directional drilling mode, core drilling mode, and in-situ electric closed pressure maintenance mode. The initial working mode of the drill bit is full-face directional drilling mode. In full-face directional drilling mode, the bottom sealing ball valve (104) and the top sealing ball valve (105) are closed, the openable drill bit (101) is closed, and there is no coal core in the core tube (103). When the drilling tool is in the core drilling mode, the bottom sealing ball valve (104) and the top sealing ball valve (105) are opened, the openable drill bit (101) is opened, and the coal core gradually enters the core drilling inner tube (103). The drilling tool is in the in-situ electric closed pressure holding mode. The bottom sealing ball valve (104) and the top sealing ball valve (105) are closed. The core tube (103) contains the coal core after the core is taken.

3. The drilling-while-drilling directional electric sealed pressure-maintaining coring tool based on a hollow screw motor as described in claim 1, characterized in that, The inner tube (103) of the core extraction tube is provided with a radially through bottom rotating shaft through hole (108) on the side wall near the bottom of the axial direction. One end of the rotating shaft of the bottom sealing ball valve (104) extends out of the inner tube (103) through the bottom rotating shaft through hole (108). A bottom gear (116) is also coaxially mounted on one end of the rotating shaft of the bottom sealing ball valve (104). The bottom gear (116) meshes with the bottom rack (10102). The inner tube (103) of the core sampler is provided with a radially penetrating bottom pin through hole (109) on the side wall near the bottom of the axial direction. The other end of the rotating shaft of the bottom sealing ball valve (104) is also provided with a bottom limiting pin (110). The bottom limiting pin (110) extends out of the inner tube (103) through the bottom pin through hole (109). The inner side wall of the drill bit body (10101) near the top of the axial direction is also provided with a bottom sliding groove (10103) along the axial direction. The bottom limiting pin (110) is slidably installed in the bottom sliding groove (10103) to realize the circumferential limitation of the inner tube (103) of the core sampler relative to the outer tube (102). The core-retrieving inner tube (103) is provided with a radially penetrating top rotating shaft through hole (111) on the side wall near the axial top. One end of the rotating shaft of the top sealing ball valve (105) extends out of the core-retrieving inner tube (103) through the top rotating shaft through hole (111). A top gear (117) is also coaxially mounted on one end of the rotating shaft of the top sealing ball valve (105). The top gear (117) meshes with the top rack (106). The inner tube (103) near the axial top is provided with a radially penetrating top pin through hole (112). The other end of the rotating shaft of the top sealing ball valve (105) is also coaxially provided with a top limiting pin (113). The top limiting pin (113) extends out of the inner tube (103) through the top pin through hole (112). The outer tube (102) near the axial top is provided with a top sliding groove (114) along the axial direction. The top limiting pin (113) is slidably installed in the top sliding groove (114) to realize the circumferential limitation of the inner tube (103) relative to the outer tube (102).

4. The drilling-while-drilling directional electric sealed pressure-maintaining coring tool based on a hollow screw motor as described in claim 1, characterized in that, A fixed cutter wing (10104) is fixedly installed on the outer periphery of the axial bottom of the drill bit body (10101) along the circumferential direction. A pair of rotatable cutter wings (10105) are also hinged to the axial bottom of the drill bit body (10101). The rotatable cutter wings (10105) are coaxially arranged inside the fixed cutter wings (10104). The axial bottom of the axially moving core tube (103) pushes the rotatable cutter wings (10105) to open, thereby opening the axial bottom of the drill bit (101).

5. The drilling-while-drilling directional electric sealed pressure-maintaining coring tool based on a hollow screw motor as described in claim 1, characterized in that, The core-taking inner tube (103) is also provided with a desorption port (107) that penetrates the end face on the axial top end face.

6. The drilling-while-drilling directional electric sealed pressure-maintaining coring tool based on a hollow screw motor as described in claim 1, characterized in that, The top of the hollow screw motor (2) is also provided with a drilling measurement section (3), a cable-guided drill rod (4) and a cable-guided water pipe (5) connected in sequence from bottom to top. The hollow screw motor (2) is also connected to the drilling measurement section (3), and the cable-guided water pipe (5) is also connected to the orifice controller (6) installed at the orifice, thereby realizing the transmission of electrical signals throughout the device.

7. The drilling-while-drilling directional electric sealed pressure-maintaining coring tool based on a hollow screw motor as described in claim 6, characterized in that, The hollow screw motor (2) also includes a drive shaft assembly (202), a universal joint assembly (203) and a motor assembly (204) connected sequentially from bottom to top along the drilling direction. The drive shaft assembly (202), the universal joint assembly (203) and the motor assembly (204) are all hollow inside and open at both ends in the axial direction. The electric drive assembly (201) includes a hollow drive section housing (20101) that is open at both ends of the axial direction. The drive section housing (20101) is located at the bottom of the transmission shaft assembly (202). The outer side wall of the upper axial section of the drive section housing (20101) is connected to the inner side wall of the lower section of the transmission shaft assembly (202). The outer side wall of the lower axial section of the drive section housing (20101) is connected to the inner side wall of the upper axial section of the core extraction tube (102). A servo electric cylinder (20102) is also coaxially installed inside the drive section housing (20101). The servo electric cylinder (20102) is connected to the core extraction tube (103) and drives the core extraction tube (103) to move axially.

8. The drilling-while-drilling directional electric sealed pressure-maintaining coring tool based on a hollow screw motor as described in claim 7, characterized in that, The servo electric cylinder (20102) includes an electric cylinder body (2010201), which is coaxially mounted in the drive section housing (20101) near the bottom of the axial direction via a first positioning ring (20103), and the electric cylinder body (2010201) is coaxially mounted in the drive section housing (20101) near the top of the axial direction via a first locking ring (20104). The electric cylinder body (2010201) is coaxially provided with an electric cylinder piston rod (2010202) at its axial bottom; the inner tube (103) is also coaxially and integrally provided with an inner tube connecting rod (115) on the outer side of its axial top end face, and the axial top of the inner tube connecting rod (115) is connected to the axial bottom of the coaxially arranged electric cylinder piston rod (2010202). The electric cylinder body (2010201) is coaxially provided with an electric cylinder drive block (2010203) at the top of the axial direction. The electric cylinder drive block (2010203) drives the electric cylinder piston rod (2010202) to move axially. The cavity in which the transmission shaft assembly (202), the universal shaft assembly (203) and the motor assembly (204) are connected is also provided with a flexible connecting rod (20105), a battery (20106) and a bottom wireless communication module (20107) connected in sequence from bottom to top. The bottom wireless communication module (20107) is also connected to the electric cylinder drive block (2010203) arranged at the bottom, thereby realizing the transmission of electrical signals in the hollow screw motor (2).

9. The drilling-while-drilling directional electric sealed pressure-maintaining coring tool based on a hollow screw motor as described in claim 8, characterized in that, The aforementioned measurement-while-drilling sub (3) includes a hollow outer tube (301) with open ends in the axial direction. A short-connecting inner tube (302) is coaxially arranged inside the outer tube (301). The short-connecting inner tube (302) is installed inside the outer tube (301) near the bottom of the axial direction via a second positioning ring (303). The short-connecting inner tube (302) is installed inside the outer tube (301) near the top of the axial direction via a second locking ring (304). The short-circuit inner tube (302) is axially connected from bottom to top with a top wireless communication module (305), a magnetic sensor module (306), an acceleration sensor module (307), a control module (308), and a wired communication module (309). The top wireless communication module (305) is connected to the bottom wireless communication module (20107) via radio electromagnetic waves, and the wired communication module (309) is wired to the top cable drill rod (4).

10. The drilling-while-drilling directional electric sealed pressure-maintaining coring tool based on a hollow screw motor as described in claim 9, characterized in that, The outer wall of the lower axial section of the short outer tube (301) is connected to the inner wall of the upper section of the hollow screw motor (2), and the inner wall of the upper axial section of the short outer tube (301) is connected to the outer wall of the lower axial section of the cable drill rod (4). The aforementioned cable drill rod (4) is also connected to the cable water pipe (5) which is coaxially arranged at the top of the axial direction.

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