Cluster hollow coring device based on small-diameter motor

Abstract

The invention relates to the technical field of drilling equipment, and discloses a cluster hollow coring device based on a small-diameter motor, the cluster hollow coring device comprises a drill bit, a plurality of screw motors, a slurry pump, a plurality of cardan shafts, a reversing assembly and a transmission shaft, the plurality of screw motors are distributed around the axis of the drill bit at intervals; the slurry pump is communicated with all the screw motors and is used for conveying drilling fluid to all the screw motors; each universal shaft is connected with an output shaft of the corresponding screw motor; the reversing assembly is connected with all the universal shafts; the transmission shaft is connected with the drill and the reversing assembly. The reversing assembly is used for converting output power of the multiple screw motors into input power of the transmission shaft. A single large-diameter screw motor is replaced by a plurality of small-diameter screw motors, and the rotor core shift distance of the small-diameter screw motor is smaller, so that the core shift vibration generated during working is reduced, the wear degree of the rotor can be effectively reduced, the failure of a pressure chamber of the motor is avoided, and the service life is prolonged.

Description

Technical Field

[0001] This invention relates to the technical field of drilling equipment, and specifically to a clustered hollow coring device based on a small-diameter motor. Background Technology

[0002] Core sampling is a crucial method for obtaining underground rock samples, and the sophistication of the equipment used directly impacts the accuracy of geological information and the results of exploration and development. Currently, in deep and ultra-deep well core sampling, conventional hollow rubber screw drills cannot meet the requirements of prolonged high-temperature operation, as rubber is prone to failure at high temperatures. Therefore, all-metal power drills are selected based on these requirements. In core sampling with large-diameter screw power drills, a common process is the combination of a hollow screw and wireline coring. Wireline coring involves using a wireline to lower the coring tool to the bottom of the borehole, obtaining the core sample, and then retrieving it using the wireline. This method can improve the efficiency of core sampling to some extent, but large-diameter all-metal motors suffer from rotor vibration. The rotor components of metal screw motors have a large eccentricity. Due to this large eccentricity, significant eccentric vibration occurs during rotor rotation. This eccentric vibration leads to increased wear between the rotor and stator, causing motor seal failure, significantly reducing drill bit efficiency, greatly shortening drill bit lifespan, and thus increasing the cost and risk of core sampling operations. Summary of the Invention

[0003] In view of this, the present invention provides a clustered hollow core sampling device based on a small-diameter motor to solve the problem of large rotor eccentricity in large-diameter screw motors. Due to the large eccentricity, significant eccentric vibration is caused during high-speed rotor rotation.

[0004] In a first aspect, this application provides a clustered hollow coring device based on a small-diameter motor, comprising: drill; Multiple screw motors are distributed at intervals around the axis of the drill bit; A mud pump, connected to all of the screw motors, is used to deliver drilling fluid to all of the screw motors; Multiple universal joints, each of which is connected to the corresponding output shaft of the screw motor; The reversing assembly is connected to all of the universal joints; The drive shaft is connected to the drill bit and the reversing assembly, respectively. The commutation assembly is used to convert the output power of the plurality of screw motors into the input power of the drive shaft.

[0005] Beneficial effects: Replacing a single large-diameter screw motor with multiple small-diameter screw motors reduces rotor eccentricity and eccentric vibration during operation, effectively decreasing rotor wear and preventing motor pressure chamber failure. This extends the service life of the clustered hollow coring device based on small-diameter motors. Simultaneously, the coordinated operation of multiple screw motors can output torque comparable to or even higher than that of a single large-diameter screw motor, achieving the dual requirements of ensuring service life and balancing high torque. Furthermore, the cooperation of the universal joint and reversing assembly allows the distributed power of multiple screw motors to be systematically transmitted to the drive shaft and drive the drill bit, ensuring the stability and reliability of power transmission and guaranteeing smooth coring operations.

[0006] In one alternative embodiment, a hydrocyclone is further included, which is in communication with each of the screw motors and with the mud pump.

[0007] Beneficial effects: Before entering the screw motor, the drilling fluid passes through a hydrocyclone separator. This separator separates larger particles from the drilling fluid, reducing the content of large impurities. This reduces the erosive effect of large impurities on the internal structure of the screw motor, further protecting it and extending its service life. It also prevents impurities from clogging the motor's internal channels, ensuring normal operating efficiency and stable power output, thus guaranteeing the continuous operation of coring.

[0008] In one alternative embodiment, the plurality of said screw motors include: The first column has multiple spiral holes, each of which is connected to the hydrocyclone separator; Multiple screws, each screw being inserted into a corresponding helical hole, and each screw being connected to the commutation assembly.

[0009] Beneficial effects: The first column has multiple spiral holes, each connected to a hydrocyclone separator, allowing multiple screws to be inserted into their corresponding spiral holes. The integrated structure of the first column facilitates the installation and positioning of multiple screws, ensuring uniform and symmetrical distribution, which is beneficial for balanced force distribution on each screw motor and improves the stability of power output. Simultaneously, the fit between the spiral holes and the screws forms a sealed chamber, efficiently converting the hydraulic energy of the drilling fluid into the mechanical energy of the screws, thus improving energy conversion efficiency. Furthermore, the structure is simple and compact, facilitating manufacturing and reducing the production difficulty and cost of the device.

[0010] In one alternative embodiment, the first column has a first through hole in the center, through which a rope passes.

[0011] Beneficial effects: A first through hole is opened in the center of the first column, and this first through hole is used for rope passage. This provides a basic channel for rope coring operations, allowing the rope to pass smoothly through the first column and cooperate with subsequent rope coring structures to achieve the rope coring function. No additional channels need to be opened on the device, ensuring the integrity and strength of the first column structure. It also makes the device structure more compact, avoiding interference from additional channels on motor installation space or power transmission, thus balancing the practical needs of power output and coring operations.

[0012] In one alternative implementation, the commutation component includes: The first gear ring is rotatably connected to the first column. Multiple drive gears, each drive gear being connected to a corresponding universal joint; The first planetary carrier is fixedly connected to the first column, and each of the driving gears is rotatably connected to the first planetary carrier; The second gear ring is rotatably connected to the first column. The diameter of the second gear ring is smaller than that of the first gear ring. The second gear ring is located inside the first gear ring, and each of the driving gears meshes with the outer teeth of the second gear ring.

[0013] Beneficial effects: Through the cooperation of the first gear ring, multiple drive gears, and the first planetary carrier, the initial adjustment of the power transmission direction and the distributed transmission of power are achieved. The drive gear is fixedly connected to the screw, enabling the power of the screw to be transmitted to the second gear ring. The first planetary carrier is fixedly connected to the first column, providing support and positioning for the drive gear and ensuring the stability of its rotation. The cooperation between the first and second gear rings enables the reduction of power and the amplification of torque. At the same time, the even distribution of multiple drive gears makes the power transmission more balanced, avoiding excessive local stress that could damage components and improving the service life and operational reliability of the commutation assembly.

[0014] In one optional implementation, the commutation component further includes: Multiple driven gears, each of which meshes with the internal teeth of the second gear ring; The second planetary carrier is fixedly connected to the first column, and each of the driven gears is rotatably connected to the second planetary carrier; The output gear is fixedly connected to the drive shaft and meshes with all the driven gears.

[0015] Beneficial effects: Through a two-stage gear transmission (driving gear - second gear ring - driven gear - output gear), two changes in rotation direction can be achieved, effectively solving the problem of the rotation direction of a single screw motor being inconsistent with the required rotation direction of a conventional drill bit. This ensures that the drive shaft can ultimately drive the drill bit to rotate in a direction consistent with the working principle, guaranteeing the normal operation of core sampling. Simultaneously, the second planetary carrier provides support and positioning for the driven gear, further improving the stability of the gear transmission. The meshing of multiple driven gears and the output gear concentrates the dispersed power to the drive shaft, improving power transmission efficiency and ensuring more even force distribution on the drive shaft, reducing wear and extending its service life.

[0016] In an alternative embodiment, a rope corer is also included, which is located within the drive shaft.

[0017] Beneficial effects: Integrating the wireline coring unit within the drive shaft allows the device to incorporate wireline coring functionality. Located inside the drive shaft, the wireline coring unit does not occupy external space, ensuring the overall compactness of the device. During coring operations, the wireline coring unit enables rapid retrieval and extraction of rock cores without needing to pull up the entire drill string, shortening auxiliary time, improving efficiency, and reducing operating costs. Simultaneously, the drive shaft protects the wireline coring unit from external impacts or erosion by impurities during drilling, ensuring its normal operation.

[0018] In one alternative embodiment, the drive shaft rotates clockwise.

[0019] Beneficial effects: The drive shaft rotates clockwise, which aligns with the working direction of conventional drill bits, conforming to the basic working principle of coring operations. This design ensures the drill bit operates at the optimal rotation direction for drilling and coring, improving drilling efficiency and coring quality, and avoiding increased drilling resistance, accelerated drill bit wear, and core breakage caused by misaligned rotation directions. Furthermore, the clockwise rotation of the drive shaft improves compatibility with existing drilling equipment, eliminating the need for adjustments to other components, reducing the difficulty of application, and enhancing the device's versatility and practicality.

[0020] In one alternative embodiment, the hydrocyclone separator has a centrally located pipe that communicates with a first through-hole.

[0021] Beneficial effects: The central pipe of the hydrocyclone is connected to the first through hole of the first column. This creates a continuous channel between the central pipe and the first through hole, which serves as the path for the rope, ensuring smooth passage through the hydrocyclone and the first column. This provides a smoother path for rope coring operations. Simultaneously, the continuous channel structure prevents the rope from getting stuck or worn during passage, protecting the rope, extending its service life, and reducing the probability of rope breakage and other safety hazards during operation, thus ensuring the safe and stable conduct of rope coring operations. Attached Figure Description

[0022] To more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0023] Figure 1 A cross-sectional view of a clustered hollow coring device based on a small-diameter motor provided in an embodiment of this application; Figure 2 for Figure 1 A magnified view of a portion of the center circle A; Figure 3 A cross-sectional view of a clustered hollow coring device based on a small-diameter motor in the first stage of core extraction, provided in an embodiment of this application. Figure 4 A cross-sectional view of a clustered hollow coring device based on a small-diameter motor in the second stage of core extraction, provided in an embodiment of this application; Figure 5 A schematic diagram of the cross-sections of multiple screw motors in a clustered hollow coring device based on a small-diameter motor, provided for an embodiment of this application; Figure 6 This is a schematic diagram of the universal joint and reversing assembly in a clustered hollow core sampling device based on a small-diameter motor, provided in an embodiment of this application.

[0024] Explanation of reference numerals in the attached figures: 101. Drill bit; 201. First column; 202. Screw; 203. First through hole; 300. Universal joint; 401. First gear ring; 402. Driving gear; 403. Second gear ring; 404. Driven gear; 405. Output gear; 500. Drive shaft; 600. Hydrocyclone separator; 700. Rope core extractor. Detailed Implementation

[0025] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, not all embodiments. Based on the embodiments in this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0026] In the description of this application, it should be noted that the terms "core," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used solely for the convenience of describing this application and for simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this application. Furthermore, the terms "first," "second," and "third" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0027] In the description of this application, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection between two components. Those skilled in the art can understand the specific meaning of the above terms in this application according to the specific circumstances.

[0028] Furthermore, the technical features involved in the different embodiments of this application described below can be combined with each other as long as they do not conflict with each other.

[0029] The technical solutions in the embodiments of the present invention will be further described in detail below with reference to the accompanying drawings. The described embodiments are only possible technical implementations of the present invention, but are not limited thereto. Other embodiments obtained by those skilled in the art in conjunction with the embodiments of the present invention without creative effort are also within the protection scope of the present invention.

[0030] This application mainly adopts multiple small-diameter screw motors in clustered core sampling to achieve a balance between lifespan and torque. It achieves the effect of ensuring the service life of the core sampling device while also ensuring high torque and stable and reliable power transmission. The following is a further detailed description of this application.

[0031] The hollow coking device based on a small-diameter motor provided in this application embodiment, such as... Figures 1 to 6 As shown, the system includes a drill bit 101, multiple screw motors, a mud pump, multiple universal joints 300, a reversing assembly, and a drive shaft 500. The multiple screw motors are spaced apart around the axis of the drill bit 101. The mud pump is connected to all the screw motors and is used to deliver drilling fluid to them. Each universal joint 300 is connected to the output shaft of its corresponding screw motor. The reversing assembly is connected to all the universal joints 300. The drive shaft 500 is connected to both the drill bit 101 and the reversing assembly. The reversing assembly converts the output power of the multiple screw motors into the input power of the drive shaft 500, achieving the effects of reducing rotor wear, preventing motor pressure chamber failure, extending the service life of the device, outputting high torque, and ensuring stable and reliable power transmission, thus guaranteeing smooth coring operations. This is because the small-diameter screw motor has a smaller rotor eccentricity, reducing eccentric vibration during operation and thus reducing rotor wear. The coordinated operation of multiple screw motors also outputs high torque, and the universal joints 300 and the reversing assembly work together to ensure orderly power transmission.

[0032] like Figure 5 and Figure 6 As shown, specifically, the multiple screw motors include a first column 201 and multiple screws 202. The first column 201 is a one-piece structure made of high-strength metal material. In this embodiment, the first column 201 is made of alloy steel, which can withstand greater pressure and impact, ensuring long-term use in harsh downhole environments. The first column 201 has multiple helical holes, which are evenly distributed along the circumference of the first column 201. This even distribution of the helical holes helps to balance the force on each screw 202 and facilitates the even flow of drilling fluid into each helical hole. The helical holes are helical in shape and, when combined with the screws 202, can form a sealed chamber. In actual processing, the helical holes can be manufactured using a combination of casting and precision milling processes to ensure the accuracy and surface quality of the helical holes. The first column 201 can be made of ceramic or other composite materials. Each spiral hole is connected to the hydrocyclone 600, so that the purified drilling fluid flowing out of the hydrocyclone 600 can smoothly enter the spiral hole to provide power for the screw motor.

[0033] like Figure 5 and Figure 6As shown, each screw 202 is a slender cylindrical part, and each screw 202 is provided with a helical structure that fits tightly with the helical hole on the first column 201. The screw 202 is made of a metal material with good wear resistance. In this embodiment, the screw material is preferably stainless steel, which can resist the wear of impurities in the drilling fluid and improve its service life. After the screw 202 is inserted into the corresponding helical hole, it can rotate in the helical hole under the action of the drilling fluid, converting the hydraulic energy of the drilling fluid into mechanical energy. Furthermore, the screw 202 can also be treated with a special coating to further improve its wear resistance and corrosion resistance. The special coating can be a tungsten carbide coating. Each screw 202 is connected to the reversing assembly through a corresponding universal joint, thereby transmitting the power it receives to the reversing assembly.

[0034] like Figure 5 and Figure 6 As shown, each screw 202 is installed in a corresponding helical bore, forming multiple independent sealed chambers. When drilling fluid enters the helical bore, it drives the screw 202 to rotate. Due to the characteristics of the helical structure, the screw 202 can only rotate along the helical bore, thus efficiently converting the hydraulic energy of the drilling fluid into the mechanical energy of the screw 202. This allows multiple screws 202 to work synchronously and output power together, thereby ensuring the power supply of the entire coring device.

[0035] Specifically, such as Figure 6 As shown, the reversing assembly includes a first ring gear 401, multiple driving gears 402, a first planetary carrier, a second ring gear 403, multiple driven gears 404, a second planetary carrier, and an output gear 405. The first ring gear 401 is a ring-shaped gear structure, rotatably connected to the first column 201. The first ring gear 401 uses sliding bearings or rolling bearings to achieve this rotatable connection with the first column 201. Bearings reduce friction and improve transmission efficiency. The first ring gear 401 is made of high-strength alloy steel to ensure it can withstand large torques. During manufacturing, the tooth accuracy of the first ring gear 401 must be ensured to avoid poor meshing. Besides alloy steel, powder metallurgy materials can also be used to manufacture the first ring gear 401 to reduce costs.

[0036] like Figure 5 and Figure 6As shown, each drive gear 402 is connected to its corresponding screw 202 via a universal joint 300, ensuring that the power from each screw 202 is transmitted to its corresponding drive gear 402. The number of teeth on the drive gear 402 is designed according to the actual transmission ratio requirements. The material of the drive gear 402 is the same as that of the first gear ring 401, and the drive gear 402 is also made of high-strength alloy steel. The shape of the drive gear 402 is a standard involute gear shape, which ensures good meshing performance. Furthermore, the drive gear 402 can undergo surface carburizing and quenching or other heat treatment processes to improve its hardness and wear resistance. Each drive gear 402 is rotatably connected to the first planetary carrier, which supports and positions the drive gear 402.

[0037] In this embodiment, the first planetary carrier is fixedly connected to the first column 201. The first planetary carrier is a frame structure composed of multiple support arms. The material of the first planetary carrier can be carbon steel or aluminum alloy. The function of the first planetary carrier is to ensure the stability of the driving gear during rotation, enabling it to accurately mesh with other gears.

[0038] like Figure 6 As shown, the second gear ring 403 is rotatably connected to the first column 201 via a bearing. The diameter of the second gear ring 403 is smaller than that of the first gear ring 401, and it is located inside the first gear ring 401. Each driving gear 402 meshes with the external teeth of the second gear ring to transmit the power of the driving gear 402 to the second gear ring 403. The material and processing requirements of the second gear ring 402 are the same as those of the first gear ring 401 to ensure the precision and strength of its teeth.

[0039] like Figure 6 As shown, in this embodiment, each of the multiple driven gears 404 meshes with the internal teeth of the second gear ring 403. The structure of the driven gear 404 is the same as that of the driving gear, and it is also a standard involute gear. The material of the driven gear 404 must also have high strength and wear resistance. When it meshes with the internal teeth of the second gear ring, it can further transmit power and change the direction of rotation. The second planetary carrier is fixedly connected to the first column 201, and each driven gear 404 is rotatably connected to the second planetary carrier. The function of the second planetary carrier is the same as that of the first planetary carrier. The second planetary carrier is used to support and position the driven gear 404, ensuring the stability of the rotation of the driven gear 404.

[0040] like Figure 6 As shown, the output gear 405 is fixedly connected to the drive shaft 500 and meshes with all the driven gears 404. The output gear 405 concentrates the power transmitted from the driven gears 404 to the drive shaft 500. The size and number of teeth of the output gear 405 are designed according to the torque and speed requirements of the drive shaft 500.

[0041] like Figure 5 and Figure 6 As shown, the reversing assembly uses a multi-stage gear transmission to achieve power transmission and rotation direction change. The driving gear 402 transmits the power of the screw 202 to the second gear ring 403, which then transmits the power to the driven gear 404. Finally, the driven gear 404 transmits the power to the output gear 405, thereby driving the transmission shaft 500 to rotate. This two-stage gear transmission method enables two rotation direction changes, ensuring that the transmission shaft 500 ultimately drives the drill bit 101 to rotate in a direction consistent with the working principle. It also achieves both distributed and concentrated power transmission, making power transmission more balanced and efficient.

[0042] Specifically, such as Figure 1 and Figure 2 As shown, it also includes a hydrocyclone separator 600, which is connected to each screw motor 202 and to the mud pump. The hydrocyclone separator 600 is a device that operates on the principle of centrifugal force. Its main structure is a combination of a cylinder and a cone. The hydrocyclone separator 600 is made of a wear-resistant metal material, such as cast iron, and has a special spiral channel design inside. Drilling fluid enters the hydrocyclone separator 600 from the inlet at a certain tangential velocity. Under the action of centrifugal force, larger particles are thrown against the cylinder wall and then move downwards along the cylinder wall, exiting from the sand discharge port at the bottom. The purified mud flows out from the overflow port at the top and enters the screw motor 202. Besides metal materials, the hydrocyclone separator 600 can also be made of engineering plastics to reduce weight and cost, but attention must be paid to its high-temperature resistance and corrosion resistance. The hydrocyclone separator 600 is connected to the mud pump and screw motor 202 via pipelines, which must have certain pressure resistance and sealing properties. The function of the hydrocyclone separator 600 is to separate larger particles from the drilling fluid before it enters the screw motor 202, reducing the content of large particle impurities. This reduces the erosive effect of large particle impurities on the internal structure of the screw motor 202, protecting the motor and extending its service life. It also prevents impurities from clogging the internal channels of the motor, ensuring normal operating efficiency and stable power output.

[0043] Specifically, such as Figure 2 and Figure 5As shown, a first through hole 203 is provided in the center of the first column 201 for the rope to pass through. The first through hole 203 is a circular channel that runs through the core of the entire first column 201. Its inner wall must be smooth to reduce friction when the rope passes through. The existence of the first through hole 203 provides a channel for rope coring operations, allowing the rope to pass smoothly through the first column 201 and cooperate with subsequent rope coring related structures to achieve the rope coring function. The opening of the first through hole 203 does not have a significant impact on the overall structural strength of the first column 201; on the contrary, it ensures the compactness of the device structure and avoids interference from additional channels on motor installation space or power transmission.

[0044] Specifically, such as Figure 3 and Figure 4 As shown, it also includes a wireline coring unit 700, which is located within the drive shaft 500. The wireline coring unit 700 is a key component for rapid core retrieval and extraction. It typically consists of multiple sub-mechanisms, including a retrieval spear mechanism and a spring-loaded positioning mechanism. Wireline coring units are standard equipment in this field and will not be described in detail here. The outer shell of the wireline coring unit 700 is made of high-strength alloy material to ensure it can withstand certain pressure and impact forces downhole. The wireline coring unit 700 is installed within the drive shaft 500 and connected to surface equipment via a rope. During coring operations, once the core enters the coring unit, the coring unit can be quickly pulled to the surface using the rope. Figure 3 This is a cross-sectional view of the first stage of core extraction. Figure 4 This is a cross-sectional view of the second stage of core extraction, without the need to remove the entire drill string. The wireline coring unit 700 is located inside the drive shaft 500, occupying no external space and ensuring the compactness of the overall structure. Simultaneously, the drive shaft 500 protects the wireline coring unit 700 from external impacts or erosion by impurities during drilling, ensuring its normal operation, improving the efficiency of coring operations, and reducing operating costs.

[0045] Specifically, such as Figure 1 and Figure 2As shown, the drive shaft 500 rotates clockwise. The drive shaft 500 is a slender shaft component, typically made of high-strength alloy steel, possessing good torsional strength and fatigue resistance. The drive shaft 500 is connected to the drill bit 101 and the reversing assembly via a coupling to ensure reliable power transmission. The clockwise rotation of the drive shaft 500 aligns with the operating direction of the conventional drill bit 101, conforming to the basic working principle of core sampling. This ensures that the drill bit 101 performs core sampling with the optimal rotation direction, improving drilling efficiency and core quality, and avoiding increased drilling resistance, accelerated wear of the drill bit 101, and core breakage caused by misaligned rotation directions. Furthermore, the clockwise rotation of the drive shaft 500 improves compatibility with existing drilling equipment, eliminating the need for adjustments to other supporting equipment, reducing the application difficulty of the device, and enhancing its versatility and practicality.

[0046] Specifically, such as Figure 1 and Figure 2 As shown, the hydrocyclone separator 600 has a core tube that connects to the first through hole 203. The core tube of the hydrocyclone separator 600 is a circular hollow tube, integrally formed with the separator or connected by welding. The inner diameter of the tube must match the inner diameter of the first through hole 203 to ensure smooth passage of the rope. The tube material must possess certain wear resistance and corrosion resistance, typically stainless steel. The connection between the tube and the first through hole 203 forms a continuous channel, providing a smooth path for the rope. This prevents the rope from getting stuck or worn during passage, protecting the rope, extending its service life, reducing the probability of rope breakage and other safety hazards during operation, and ensuring the safe and stable operation of rope coring.

[0047] The implementation principle of this embodiment is as follows: This device replaces a single large-diameter screw motor 202 with multiple small-diameter screw motors 202. Utilizing the characteristics of small-diameter screw motors 202—small rotor eccentricity and low eccentricity vibration—it effectively reduces rotor wear, avoids motor pressure chamber failure, and significantly extends the device's service life. The coordinated operation of multiple screw motors 202 can output torque comparable to or even higher than a single large-diameter screw motor 202, achieving the dual requirements of ensuring service life and balancing high torque. The hydrocyclone separator 600 pre-treats the drilling fluid, separating large particles of impurities, reducing erosion and blockage of the screw motors 202, and further protecting the motors. The reversing assembly, through multi-stage gear transmission, realizes power transmission and changes in rotation direction, ensuring that the drive shaft 500 drives the drill bit 101 to rotate clockwise, conforming to the working principle. The wireline coring device 700 is integrated within the drive shaft 500, enabling rapid retrieval and extraction of the core, improving coring efficiency, while the drive shaft 500 also protects it. The entire device has a compact and reasonable structural design, which improves its overall performance and reliability. Compared with existing technologies, it has significant improvements and advantages and can better meet the needs of downhole coring operations.

[0048] In this embodiment, the clustered hollow coring device based on a small-diameter motor is mainly used in high-temperature downhole environments.

[0049] Although embodiments of the invention have been described in conjunction with the accompanying drawings, those skilled in the art can make various modifications and variations without departing from the spirit and scope of the invention, and such modifications and variations all fall within the scope defined by the appended claims.

Claims

1. A small diameter motor based cluster hollow coring device, characterized by, The drilling rig comprises: a drill bit (101); a plurality of screw motors, which are spaced apart along the axis of the drill bit (101); a mud pump, which is connected to all the screw motors and is used to deliver drilling fluid to all the screw motors; a plurality of universal shafts (300), each of which is connected to a corresponding screw motor output shaft; a reversing assembly, which is connected to all the universal shafts (300); a transmission shaft (500), which is connected to the drill bit (101) and the reversing assembly, respectively; the reversing assembly is used to convert the output power of the plurality of screw motors into the input power of the transmission shaft (500).

2. The small-diameter motor-based, bundled hollow coring apparatus of claim 1, wherein, The drilling rig further comprises a hydrocyclone (600), which is connected to each of the screw motors and is connected to the mud pump.

3. The small-diameter motor-based, bundled hollow coring apparatus of claim 2, wherein, The plurality of screw motors comprises: a first column (201), which is provided with a plurality of spiral holes, each of which is connected to the hydrocyclone (600); a plurality of screw rods (202), each of which is inserted into a corresponding spiral hole and is connected to the reversing assembly.

4. The small-diameter motor-based, bundled hollow coring apparatus of claim 3, wherein, The first column (201) is centrally provided with a first through hole (203) for a rope to pass through.

5. The small-diameter motor-based, bundled hollow coring apparatus of claim 4, wherein, The reversing assembly comprises: a first ring gear (401), which is rotatably connected to the first column (201); a plurality of driving gears (402), each of which is connected to a corresponding universal shaft (300); a first planet carrier, which is fixedly connected to the first column (201) and rotatably connected to each of the driving gears (402); a second ring gear (403), which is rotatably connected to the first column (201) and has a smaller diameter than the first ring gear (401), the second ring gear (403) is located inside the first ring gear (401), and each of the driving gears (402) is meshed with the outer teeth of the second ring gear (403).

6. The small-diameter motor-based, bundled hollow coring apparatus of claim 5, wherein, The reversing assembly further comprises: a plurality of driven gears (404), each of which is meshed with the inner teeth of the second ring gear (403); a second planet carrier, which is fixedly connected to the first column (201) and rotatably connected to each of the driven gears (404); an output gear (405), which is fixedly connected to the transmission shaft (500) and is meshed with all the driven gears (404).

7. The small-diameter motor-based, bundled hollow coring apparatus of claim 6, wherein, The drilling rig further comprises a rope corer (700), which is located in the transmission shaft (500).

8. The small-diameter motor-based, bundled hollow coring apparatus of claim 7, wherein, The transmission shaft (500) rotates clockwise.

9. The small-diameter motor-based, bundled hollow coring apparatus of claim 8, wherein, The hydrocyclone (600) is centrally provided with a pipe, which is connected to the first through hole (203).

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