Novel horizontal directional drilling machine for closed slurry returning and chip removal

Abstract

The invention provides a novel closed slurry return and chip removal horizontal directional drilling machine, which consists of an inner and outer double-channel drilling machine main machine, an inner and outer double-channel drilling rod and a novel drill bit, and is characterized in that a power head main shaft of the inner and outer double-channel drilling machine main machine, the inner and outer double-channel drilling rod and a core shaft of the novel drill bit are respectively provided with an inner hole channel and an outer layer channel; a slurry returning and chip discharging opening leading to the inner hole channel is formed in the shaft wall of the core shaft of the novel drill bit, and a slurry jetting opening is formed in the novel drill bit. When the drilling machine works, slurry is injected from the outer layer channel until being ejected from the slurry injection orifice of the novel drill bit, and the ejected slurry and drilling cuttings are mixed to enter the inner hole channel of the mandrel from the slurry return and chip removal opening of the mandrel of the novel drill bit, and return to the inner hole channel of the main machine through the inner hole channel of the double-channel drill rod to be discharged. The full chip removal function in hole forming is achieved, the one-time hole forming capacity of the drilling machine is greatly improved, and therefore the construction period is greatly shortened, the cost and energy consumption are reduced, and the labor intensity and the influence on the environment are reduced.

Description

Technical Field

[0001] This invention belongs to the field of horizontal directional drilling technology, specifically relating to a novel closed-loop slurry return and chip removal horizontal directional drilling rig. Background Technology

[0002] Regardless of the type of drilling rig, the removal of drill cuttings during drilling is a crucial step. Engineering drilling rigs are broadly classified into two types based on their cuttings removal methods: wet and dry. Wet drilling involves injecting drilling mud during drilling, relying on the mud's backflow to remove cuttings; dry drilling uses compressed air backflow or mechanical methods to remove cuttings. Horizontal directional drilling is a wet method, meaning it relies on the backflow of drilling mud for cuttings removal.

[0003] Most drilling rigs in engineering operations drill vertical holes, while horizontal directional drilling (WD) drills horizontal holes. Even with the same mud return and cuttings removal method, the cuttings removal effect in horizontal holes is not as good as in vertical holes. This is because: (1) Drill cuttings cut in horizontal boreholes tend to settle downwards due to their own weight, while the direction of mud return is horizontal. Drill cuttings with greater weight that cannot be suspended by mud will settle at the bottom of the hole. Unless the returning mud has a very high flow velocity, creating turbulent scouring at the bottom of the hole, the drill cuttings can not be completely removed.

[0004] (2) Drill cuttings from vertical drilling will also sink due to their own weight, but the mud backflow is vertically upward, so the drill cuttings are difficult to settle and are easier to remove.

[0005] The structure and cuttings removal methods of traditional horizontal directional drilling rigs: 1. A traditional horizontal directional drilling rig consists of a drilling rig main unit, drill rods, and drill bits; 2. The traditional horizontal directional drilling rig pipeline laying process is: first guide, then borehole drilling, and then pipe pulling. (1) Guiding means inserting the drill rod into the drill rod in advance along the axis of the underground pipeline to be laid; (2) Hole making is to connect a drill bit to one end of the drill rod that has been inserted, and use a horizontal drilling machine to drive the drill bit to rotate while pulling back, so as to drill a hole that is large enough for the pipe to pass through smoothly. (3) Pulling pipe means pulling the pipe into the drilled hole.

[0006] Of the three processes mentioned above, the most costly and time-consuming is hole formation, and the key to hole formation lies in chip removal.

[0007] 3. Chip removal methods and effects during traditional horizontal directional drilling: (1) Mud circulation method: Traditional horizontal directional drilling relies on mud return and cuttings removal when drilling. While the drilling bit rotates and cuts the soil, the drilling rig injects mud into the drill rod, which is then ejected by the reaming bit, forming a mud return flow that flows towards the outlets at both ends of the borehole.

[0008] During grouting, the mud flows through a closed channel inside the drill pipe, where the pressure and flow rate are controllable. After the mud is ejected from the drill bit, it is in an open and free state, flowing towards areas with lower pressure. In this case, the mud pressure and flow rate are uncontrollable and depend on the environment inside the borehole. This type of mud circulation is called "open-loop grouting".

[0009] (2) The effect of "open-type return mud" on mud chip removal: For horizontal cuttings removal, the return mud velocity must reach a level that creates turbulence to achieve thorough cuttings removal. However, horizontal directional drilling rigs require large-diameter horizontal holes for pipeline laying. During the drilling process, the mud undergoes "open return," resulting in a very low horizontal mud return velocity and a laminar flow pattern, far from achieving turbulence. Therefore, it can only partially remove cuttings, often resulting in less cuttings being removed and more being deposited at the bottom of the hole. This situation becomes even more severe when laying large-diameter pipelines.

[0010] Therefore, the chip removal in traditional horizontal directional drilling is "incomplete chip removal." "Incomplete" means that a complete channel for the pipe is not formed during the hole formation stage; most of the space in the hole created by the drill bit is occupied by deposited drill cuttings. These cuttings cannot be removed during the hole formation stage; they are only forced out by the incoming pipe during the pipe pulling stage. In other words, most of the chip removal in traditional horizontal directional drilling is completed during the pipe pulling stage.

[0011] 4. Problems arising from traditional chip removal methods in horizontal directional drilling rigs: Insufficient chip removal is a serious shortcoming of traditional horizontal directional drilling rigs, which leads to two consequences: (1) The drill cuttings that cannot be removed from the hole wrap around and squeeze the drill bit, which creates a huge resistance to the rotational movement of the drill bit to further cut the formation. The torque consumed by this resistance is far greater than the torque required for the drill bit to cut the formation.

[0012] According to our research, the torque actually used by traditional horizontal directional drilling rigs to cut the formation during hole formation is less than 20% of the total output torque of the rig, and in some cases even lower. In other words, the vast majority of the torque used by traditional horizontal directional drilling rigs during hole formation is consumed by the friction between the drill string and the drill cuttings.

[0013] (2) Drill cuttings that are not removed during drilling will also create huge resistance to the advancement of the pipe during pipe pulling.

[0014] 5. Hole-forming techniques that must be adopted under conditions of insufficient chip removal: In traditional horizontal directional drilling, to ensure the successful completion of the final pipe pulling during pipeline laying, the following technical measures can only be adopted: (1) Expand the hole gradually from small to large to reduce the torque required for each expansion: There is an economical and reasonable range for the output torque, power, and load-bearing capacity of the drilling rig main unit. It is impossible to increase the torque indefinitely. Traditional process reaming drill bits have high rotational resistance, and the torque required for large-diameter holes in one operation is too high. The conventional configuration of drilling rigs and drill rods cannot meet this requirement. The only way is to gradually increase the hole size from small to large in order to reduce the torque required for each reaming operation.

[0015] (2) Repeated grinding to reduce tube drawing resistance: Since it is difficult to remove drill cuttings from horizontal holes, it is necessary to control the drilling depth during reaming, inject more grout, and rotate more to ensure that the drill cuttings are crushed by the drill bit as much as possible and suspended in the mud for removal. The drill cuttings that cannot be removed are also fully mixed with the mud and become fluid, so that they can be smoothly squeezed out of the hole when the pullback pipe enters, without causing serious obstruction to the pullback pipe.

[0016] (3) Increase the borehole diameter to reduce the risk of pipe pulling: Even with repeated reaming, large particles that cannot be crushed by the drill bit, such as coarse sand, pebbles, and gravel, will inevitably remain. These particles cannot be squeezed out when pulling back the pipe, so the reaming diameter must be increased. Therefore, traditional horizontal directional drilling specifications require that the reaming diameter must be 1.2 to 1.5 times the diameter of the pipe to be laid.

[0017] Engineering defects of traditional horizontal directional drilling rigs during the hole-forming stage: 1. Low single-pass hole formation rate and complex hole formation process: Traditional horizontal directional drilling only dares to complete a hole in one go when laying pipes with a very small diameter that is slightly larger than the drill rod diameter. The vast majority of projects complete the hole formation by gradually enlarging the hole. This turns the single process of horizontal directional drilling into multiple processes.

[0018] 2. Reamer bits have high torque load and high consumption: Even with multi-stage reaming, the large amount of drill cuttings left at the bottom of the hole means that each stage of reaming still requires a large torque to rotate, resulting in huge power consumption. In addition, repeated grinding and enlarging of the hole diameter are necessary to ensure smooth pipe pulling. All these measures come at the cost of excessive mechanical output power and working time in order to meet the hole formation requirements.

[0019] 3. High labor intensity: Multi-stage borehole reaming requires the continuous transport of drill rods, which necessitates the constant transport of drill rods removed from the drilling rig during the pullback reaming process from the entry point to the exit point for reconnection. This is a very demanding task, and if there is no direct road between the entry and exit points, transporting the drill rods incurs a significant cost.

[0020] 4. Large amount of mud used, significant environmental impact. Multi-stage reaming requires a large amount of drilling mud. In order to remove more drill cuttings during drilling, the mud must be prepared with high concentration and high viscosity to ensure the mud's ability to suspend the drill cuttings. This requires more bentonite. In many projects, various chemical additives are added to the mud to further improve its suspension ability. This not only results in huge costs but also has adverse environmental impacts.

[0021] Analysis Summary: Horizontal directional drilling rigs, as a relatively convenient pipe-laying device, are becoming increasingly popular in pipeline construction. At the same time, the market demand for pipe diameters laid by horizontal directional drilling rigs is also increasing. For example, many newly built sections of my country's main natural gas pipeline network have pipe diameters reaching 1219mm.

[0022] Currently, domestic practices involve continuously increasing the torque and power requirements of drilling rigs and expanding the diameter of drill rods, resulting in huge investments in engineering equipment. However, simply relying on increasing the power of equipment is ultimately limited.

[0023] The above analysis reveals serious flaws in the fundamental principles of traditional horizontal directional drilling (LDR) rigs, indicating significant room for improvement. The best approach is to fundamentally enhance LDR rigs with more advanced hole-forming capabilities, significantly increasing hole-forming capacity without increasing torque or power, to meet the engineering needs of large-diameter pipelines. Summary of the Invention

[0024] The purpose of this invention is to provide a new type of closed-loop slurry return and chip removal horizontal directional drilling rig, which can achieve full chip removal during hole formation. Without increasing the torque and power of existing drilling rigs, it can significantly improve the drilling rig's one-time hole formation capability. Pipe laying projects do not require staged hole enlargement, thereby significantly shortening the construction period, reducing costs and energy consumption, reducing labor intensity and environmental impact.

[0025] The specific technical solution adopted by this invention is as follows: A novel closed-loop slurry return and cuttings removal horizontal directional drilling rig comprises an inner and outer dual-channel drilling rig main unit, inner and outer dual-channel drill rods, and a novel drill bit. Its features include: the power head spindle of the inner and outer dual-channel drilling rig main unit, the inner and outer dual-channel drill rods, and the mandrel of the novel drill bit all having inner and outer channels; the mandrel wall of the novel drill bit has a slurry return and cuttings removal port leading to the inner channel, and the novel drill bit has a mud injection port; during drilling operation, slurry is injected from the outer channel of the inner and outer dual-channel drilling rig main unit, flows through the outer channel of the inner and outer dual-channel drill rods to the outer channel of the novel drill bit mandrel, and is ejected from the mud injection port of the novel drill bit. The ejected mud mixes with drill cuttings and enters the inner channel of the mandrel from the slurry return and cuttings removal port of the novel drill bit mandrel, then returns through the inner channel of the dual-channel drill rods until it is discharged from the inner channel of the main unit.

[0026] The inner and outer channels of the dual-channel drilling rig are respectively composed of two channels: the central channel of the main shaft inside the power head spindle and the outer channel of the main shaft. The central channel of the main shaft is formed by the central shaft hole of the main shaft and serves as a grout return and chip removal channel. The outer channel of the main shaft is an annular channel machined from the inside of the shaft wall and serves as a grouting channel. The specific structure is as follows: (1) The spindle center hole of the power head spindle of the internal and external dual-channel drilling rig main unit runs through the front and rear, which is the slurry return and chip removal channel. The rear end is equipped with a rotary water seal interface for connecting the slurry discharge pipe. (2) The outer channel of the main shaft is located in the part of the power head main shaft of the inner and outer double channel drilling machine. The rear end of the outer channel of the main shaft is provided with several radial grouting holes. The radial grouting holes are connected to the outer channel of the main shaft. The shaft section of the radial grouting holes is provided with an annular rotating water seal interface for connecting the grouting pipe. (3) The front end of the power head spindle of the internal and external dual-channel drilling rig host is provided with a connector that connects to the internal and external dual-channel drill rod.

[0027] The inner and outer channels of the dual-channel drill rod are respectively formed by the inner tube of the drill rod body and the annular cavity between the inner and outer tubes. Both ends of the drill rod body are provided with a male connector and a female connector, which are mating threaded joints. Each of the male and female connectors has an annular water passage groove corresponding to the position of the annular cavity, and the annular water passage groove contains several water passage holes connecting the annular cavities. When the drill rods are joined, they are connected by the threaded male and female connectors of the two drill rods. The annular cavities of the two drill rods are connected through the annular water passage grooves and water passage holes inside the interconnected male and female connectors, thus forming a continuous outer channel of the drill rod located inside the rod wall. The inner tubes of the two drill rods are joined together to form a continuous central channel of the drill rod located inside the inner tube.

[0028] Preferably, the male connector body has a sealing ring groove at its root, with a sealing ring inside; after being connected to the female connector body of another drill pipe, the inner wall of the end of the female connector body and the sealing ring at the root of the male connector body are pressed together, forming a seal between the outer channel of the drill pipe and the outside world.

[0029] Preferably, the male connector body has an extension section of the same diameter as the threaded portion after the threaded end at its foremost end. A matching sealing channel is located at a corresponding position inside the female connector body. The extension section has a sealing ring groove on its circumference, containing a sealing ring. When the two drill pipes are threaded together, the extension section of the male connector body inserts into the sealing channel inside the female connector body, forming a seal between the outer channel and the central channel of the drill pipe.

[0030] Furthermore, the male and female connectors are tapered threaded connectors, which makes alignment easier during connection.

[0031] The present invention also provides an alternative to the internal and external dual-channel drill pipe: the internal and external dual-channel drill pipe is composed of an inner tube and an outer tube. The inner tube is held and fixed at the center of the inner hole of the outer tube by a support frame. The internal space of the outer tube is divided into two channels: the inner tube hole and the double-wall sandwich between the outer wall of the inner tube and the inner wall of the outer tube. These channels serve as the inner hole channel and the outer layer channel of the internal and external dual-channel drill pipe, respectively. The two ends of the outer tube are respectively provided with a matching male thread connector and a female thread connector. The two ends of the inner tube are respectively provided with a matching male thread connector and a female thread connector.

[0032] Preferably, the male threaded connector of the outer tube body and the female threaded connector of the inner tube body are arranged in the same direction.

[0033] The new drill bit consists of a cutting disc and a drill bit holder. The drill bit holder is a pressure-holding cylinder made of rolled steel plate. A vertical plate is welded and fixed inside the pressure-holding cylinder, and a mandrel seat is fixedly installed at the center of the vertical plate. A hollow mandrel extending towards the soil is rotatably fixed inside the mandrel seat. The cutting disc is installed and fixed at the soil-facing end of the hollow mandrel. Several cutting tools and several mud injection nozzles are provided on the soil-facing surface of the cutting disc. The cutting disc, the vertical plate of the drill bit holder, and the pressure-holding cylinder together form a drill cuttings collection chamber. The section of the hollow mandrel located outside the cutting disc has a double-channel structure, with an outer hollow mandrel channel and an inner hollow mandrel channel. The hollow mandrel serves as the outer channel and inner channel of the new drill bit, respectively. The outer channel extends to the connection with the cutting disk, and the inner channel extends into the drill cuttings collection chamber. The outer channel is connected to the mud injection port via a grouting pipe. The cutting disk has multiple chip inlets. The shaft wall section of the hollow mandrel within the drill cuttings collection chamber has a return slurry and chip discharge port leading to the inner channel. The mixed fluid of mud and drill cuttings entering the drill cuttings collection chamber can enter the inner channel of the hollow mandrel through the return slurry and chip discharge port, and then flow to the center channel of the drill pipe with both inner and outer channels, forming a mixed return flow of mud carrying drill cuttings.

[0034] The outer diameter of the pressure-holding cylinder of the drill bit holder is slightly smaller than the outer diameter of the front cutting disc, on the order of millimeters. As the drill bit rotates and cuts forward, the outer surface of the pressure-holding cylinder is essentially in contact with the hole wall formed by the cutting. This prevents a large amount of the high-pressure mud ejected from the front cutting disc and the drill cuttings from flowing through the gap between the pressure-holding cylinder and the hole wall to the rear of the drill bit. The majority of these materials enter the cuttings collection chamber through the cuttings inlet of the front cutting disc. Simultaneously, this maintains some pressure in the mud within the cuttings collection chamber, preventing a significant loss of pressure.

[0035] This invention also provides an alternative to a novel drill bit: the novel drill bit consists of a hollow mandrel and a drill bit body. The drill bit body has a hollow cylindrical structure with a cutting disk at the soil-facing end. Several cutting tools and several mud injection ports are arranged on the outer side of the cutting disk. The hollow mandrel is located at the center of the cutting disk and extends into the drill bit body. The section of the hollow mandrel located outside the cutting disk has a dual-channel structure, with an outer hollow mandrel channel and an inner hollow mandrel channel, serving as the outer channel and inner channel of the novel drill bit, respectively. The outer hollow mandrel channel extends to the connection point with the cutting disk, and the inner hollow mandrel channel extends into the drill bit body. The outer hollow mandrel channel is connected to the mud injection ports via a grouting pipe. The cutting disk has multiple chip inlets. The section of the hollow mandrel within the drill bit body has a return and chip removal port leading to the inner hollow mandrel channel.

[0036] The present invention also provides an alternative to a novel drill bit: the novel drill bit is composed of a hollow mandrel and a roller cone drill bit, the end of the hollow mandrel is fixedly connected to the roller cone drill bit, and the soil-facing end of the roller cone drill bit is provided with a plurality of cutting roller cones; the hollow mandrel has a dual-channel structure, with an outer hollow mandrel channel and an inner hollow mandrel channel, which serve as the outer channel and inner channel of the novel drill bit, respectively; the shaft wall of the hollow mandrel is provided with a mud injection port leading to the outer hollow mandrel channel and a mud return and chip removal port leading to the inner hollow mandrel channel.

[0037] During hole drilling operations, this invention employs a high-pressure mud pump to inject mud from the grouting port of the inner and outer dual-channel drilling rig main unit. The injected high-pressure mud enters the outer channel of the drill rod along the outer channel of the main shaft, and then enters the outer channel of the hollow mandrel of the drill bit. It is then ejected from the mud injection port in front of the cutting disc, so that the jet can work in conjunction with the drill bit cutting tool to cut the soil layer in front.

[0038] The ejected mud mixes with the cut drill cuttings and flows back from the cutting inlet in front of the cutting disc into the cutting cuttings collection chamber inside the new drill bit. Under the pressure of the mud in the cutting cuttings collection chamber, the mixed fluid formed by the mud and drill cuttings first flows in the direction with the smoothest flow and the least resistance—that is, through the mud return and chip discharge port of the hollow mandrel of the new drill bit, into the inner hole of the hollow mandrel, and then into the inner hole channel of the inner and outer double channel drill pipe to form a high-speed backflow. Finally, it is discharged from the body through the inner hole channel of the main spindle of the inner and outer double channel drilling rig.

[0039] The technical effects achieved by this invention are as follows: This invention provides a novel closed-loop slurry return and cuttings removal horizontal directional drilling rig, which can achieve more thorough removal of drill cuttings, greatly reduce torque loss during drilling, and thus significantly increase the diameter of the hole formed in one operation. This enables the horizontal directional drilling rig to achieve one-time hole formation for most pipeline laying operations, thereby reducing the construction cost and construction period of the hole formation stage by several times.

[0040] This invention significantly reduces the number of process steps, eliminates the need for personnel to move drill rods between entry and exit points and to connect drill rods, and greatly reduces labor intensity.

[0041] This invention achieves a closed-loop mud-water circulation, enabling more efficient recycling of mud, reducing mud consumption, and minimizing environmental pollution.

[0042] This invention realizes a closed-loop slurry return and chip removal borehole enlargement process. For formations with poor porosity, such as gravel and pebble formations, a high-power drilling rig can be used to complete the borehole formation and pipe pulling in one go, without worrying about the borehole collapse that occurs in traditional directional drilling, thus greatly reducing the engineering risks in harsh geological conditions. Attached Figure Description

[0043] Figure 1This is a cross-sectional structural schematic diagram of a novel closed-loop slurry return and chip removal horizontal directional drilling rig according to the present invention; Figure 2 This is a perspective view of a novel closed-loop slurry return and chip removal horizontal directional drilling rig according to the present invention; Figure 3 This is a schematic diagram of a half-section structure of a drill pipe with internal and external double channels; Figure 4 This is a half-section view of the drill pipe in the docking state of the inner and outer double channels; Figure 5 This is a schematic diagram of a half-section of the new type of drill bit; Figure 6 This is a schematic diagram of an alternative to the internal and external dual-channel drill pipe of the present invention; Figure 7 This is an AA cross-sectional view of an alternative to the internal and external dual-channel drill pipe of the present invention; Figure 8 This is a structural schematic diagram of a novel drill bit replacement solution according to the present invention; Figure 9 This is an AA cross-sectional view of a novel drill bit alternative according to the present invention; Figure 10 This is a perspective view of a novel drill bit replacement solution according to the present invention; Figure 11 This is a structural schematic diagram of another novel drill bit alternative of the present invention; Figure 12 This is an AA cross-sectional view of another novel drill bit alternative of the present invention; Figure 13 This is a perspective view of another novel drill bit alternative of the present invention.

[0044] The attached diagram lists the components represented by each number as follows: 1. Internal and external dual-channel drilling rig main unit; 2. Internal and external dual-channel drill rod; 3. New type of drill bit; 4. Power head spindle; 5. Spindle center channel; 6. Spindle outer channel; 7. Spindle center shaft hole; 8. Rotary water seal interface; 9. Radial grouting hole; 10. Annular rotary water seal interface; 11. Inner tube; 12. Outer tube; 13. Annular cavity; 14. Male connector body; 15. Female connector body; 16. Annular water passage groove; 17. Water passage hole; 18. Drill rod outer channel; 19. Drill rod center channel; 20. First sealing ring groove; 21. Extension section; 22. Sealing channel; 23. Second sealing ring 24. Groove; 25. Cutting disc; 26. Drill bit holder; 27. Pressure holding cylinder; 28. Vertical plate; 29. ​​Mandrel holder; 30. Hollow mandrel; 31. Cutting tool; 32. Mud injection port; 33. Drill cuttings collection chamber; 34. Outer channel of hollow mandrel; 35. Inner channel of hollow mandrel; 36. Grouting pipe; 37. Chip inlet; 38. Return grout and chip discharge port; 39. Inner tube hole; 40. Double-walled interlayer; 41. Male threaded connector of outer tube; 42. Female threaded connector of outer tube; 43. Male threaded connector of inner tube; 44. Female threaded connector of inner tube; 45. Drill bit body; 46. Roller cone; 47. Cutting roller cone. Detailed Implementation

[0045] To make the objectives and advantages of this invention clearer, the invention will be specifically described below with reference to embodiments. It should be understood that the following text is merely used to describe one or more specific embodiments of the invention and does not strictly limit the scope of protection specifically claimed by the invention. Example 1

[0046] This embodiment provides a novel closed-loop slurry return and cuttings removal horizontal directional drilling rig, such as... Figures 1-5 As shown, the system consists of an inner and outer dual-channel drilling rig main unit 1, an inner and outer dual-channel drill rod 2, and a new type of drill bit 3. The main spindle 4 of the power head of the inner and outer dual-channel drilling rig main unit 1, the inner and outer dual-channel drill rod 2, and the mandrel of the new type of drill bit 3 are all provided with an inner hole channel and an outer layer channel. The mandrel wall of the new type of drill bit 3 has a mud return and chip removal port 37 leading to the inner hole channel, and the new type of drill bit 3 is provided with a mud injection port 31. When the drilling rig is working, grout is injected from the outer layer channel of the inner and outer dual-channel drilling rig main unit 1, passes through the outer layer channel of the inner and outer dual-channel drill rod 2 to the outer layer channel of the mandrel of the new type of drill bit 3, and is ejected from the mud injection port 37 of the new type of drill bit 3. The ejected mud mixes with the drill cuttings and enters the inner hole channel of the mandrel from the mud return and chip removal port of the new type of drill bit 3, and then returns through the inner hole channel of the dual-channel drill rod until it is discharged from the inner hole channel of the main unit.

[0047] The inner and outer channels of the dual-channel drilling rig 1 are respectively composed of two channels: the central channel 5 and the outer channel 6 inside the power head spindle 4 of the drilling rig rig. The central channel 5 is formed by the central shaft hole 7 of the spindle and serves as a grout return and chip removal channel. The outer channel 6 is an annular channel formed by machining inside the shaft wall and serves as a grouting channel. The specific structure is as follows: (1) The spindle center hole 7 of the power head spindle 4 of the internal and external double channel drilling rig host 1 runs through the front and rear and is the slurry return and chip removal channel. The rear end is equipped with a rotary water seal interface 8 for connecting the slurry discharge pipe. (2) The outer channel 6 of the main shaft is located in the part of the power head main shaft 4 of the inner and outer double channel drilling machine host 1 that extends outward. The rear end of the outer channel 6 of the main shaft is provided with a plurality of radial grouting holes 9. The radial grouting holes 9 are connected to the outer channel 6 of the main shaft. The shaft section of the radial grouting holes 9 is provided with an annular rotating water seal interface 10 for connecting the grouting pipe. (3) The front end of the power head spindle 4 of the internal and external dual-channel drilling rig host 1 is provided with a connector that connects to the internal and external dual-channel drill rod 2.

[0048] The inner and outer channels of the inner and outer channels of the drill rod 2 are respectively formed by the inner tube 11 of the drill rod body and the annular cavity 13 between the inner tube 11 and the outer tube 12. The drill rod is provided with a male connector body 14 and a female connector body 15 at both ends. The male connector body 14 and the female connector body 15 are compatible threaded connectors with a tapered shape. The male connector body 14 and the female connector body 15 are each provided with an annular water passage groove 16 at the position corresponding to the annular cavity 13. The annular water passage groove 16 is provided with a plurality of water passage holes 17 connecting the annular cavity 13. When the drill rods are joined, they are connected by threads through the male connector body 14 and female connector body 15 of the two drill rods respectively. The annular cavities 13 of the two drill rods are connected through the annular water passage groove 16 and water passage hole 17 inside the male connector body 14 and female connector body 15, thereby forming a continuous drill rod outer layer channel 18 located inside the rod wall; the inner tubes 11 of the two drill rods are connected to each other to form a continuous drill rod central channel 19 located inside the inner tube 11.

[0049] The male connector body 14 is provided with a first sealing ring groove 20 at its root, and a sealing ring is provided inside. After it is connected to the female connector body 15 of another drill pipe, the inner wall of the end of the female connector body 15 and the sealing ring at the root of the male connector body 14 are pressed together, forming a seal between the outer channel 18 of the drill pipe and the outside world.

[0050] The male connector body 14 has an extension section 21 of the same diameter as the threaded portion at the end of the threaded section. A matching sealing channel 22 is located at a corresponding position inside the female connector body 15. A second sealing ring groove 23 is provided around the circumference of the extension section 21, containing a sealing ring. When the two drill pipes are threaded together, the extension section 21 of the male connector body 14 is inserted into the sealing channel 22 inside the female connector body 15, forming a seal between the outer channel 18 and the central channel 19 of the drill pipe.

[0051] The novel drill bit 3 consists of a cutting disc 24 and a drill bit holder 25. The drill bit holder 25 is a pressure-holding cylinder 26 made of rolled steel plate. A vertical plate 27 is welded and fixed inside the pressure-holding cylinder 26. A mandrel seat 28 is fixedly installed at the center of the vertical plate 27. A hollow mandrel 29 extending towards the soil is rotatably fixed inside the mandrel seat 28. The cutting disc 24 is installed and fixed at the soil-facing end of the hollow mandrel 29. Several cutting blades are provided on the soil-facing surface of the cutting disc 24. The drill bit 24 has a cutting disc 24 and a number of mud injection ports 31. The cutting disc 24 and the drill bit holder 25 are enclosed by the vertical plate 27 and the pressure-holding cylinder 26 to form a drill cuttings collection chamber 32. The hollow mandrel 29 located outside the cutting disc 24 has a double-channel structure, with an outer hollow mandrel channel 33 and an inner hollow mandrel channel 34, which serve as the outer channel and inner channel of the new drill bit 3, respectively. The hollow mandrel 29 located outside the cutting disc 24 has a joint for connecting with the inner and outer double-channel drill rod 2, and the joint type is the same as the joint connecting the inner and outer double-channel drill rod 2. The outer hollow mandrel channel 33 extends to the connection with the cutting disc 24, and the inner hollow mandrel channel 34 extends into the drill cuttings collection chamber 32. The outer hollow mandrel channel 33 is connected to the mud injection ports 31 through a grouting pipe 35. The cutting disc 24 has multiple chip inlets 36, and the cut drill cuttings can enter the drill cuttings collection chamber behind the cutting disc 24. 32. The drill cuttings collection chamber 32 can collect drill cuttings and maintain a certain mud pressure; the hollow mandrel 29 has a return mud and cuttings discharge port 37 in the shaft wall section inside the drill cuttings collection chamber 32, which leads to the inner hole channel 34 of the hollow mandrel; the mixed fluid of mud and drill cuttings entering the drill cuttings collection chamber 32 can enter the inner hole channel 34 of the hollow mandrel through the return mud and cuttings discharge port 37, and then lead to the drill rod center channel 19 of the inner and outer double channel drill rod 2, forming a mixed return flow of mud carrying drill cuttings.

[0052] The outer diameter of the pressure-holding cylinder 26 of the drill bit holder 25 is slightly smaller than the outer diameter of the front cutting disc 24, on the order of millimeters. When the drill bit rotates and cuts forward to form a hole, the outer surface of the pressure-holding cylinder 26 is basically in contact with the hole wall formed by the cutting. This prevents a large amount of the high-pressure mud ejected from the front cutting disc 24 and the drill cuttings from flowing through the gap between the pressure-holding cylinder 26 and the hole wall to the rear of the drill bit. Most of them enter the drill cuttings collection chamber 32 through the cuttings inlet 36 of the front cutting disc 24. At the same time, the mud pressure in the drill cuttings collection chamber 32 is maintained to prevent a significant loss of pressure.

[0053] During hole drilling operations, this invention employs a high-pressure mud pump to inject mud from the grouting port of the inner and outer dual-channel drilling rig main unit. The injected high-pressure mud enters the outer channel of the drill rod along the outer channel of the main shaft, and then enters the outer channel of the hollow mandrel of the drill bit. It is then ejected from the mud injection port in front of the cutting disc, so that the jet can work in conjunction with the drill bit cutting tool to cut the soil layer in front.

[0054] The ejected mud mixes with the cut drill cuttings and flows back from the cutting inlet in front of the cutting disc into the cutting cuttings collection chamber inside the new drill bit. Under the pressure of the mud in the cutting cuttings collection chamber, the mixed fluid formed by the mud and drill cuttings first flows in the direction with the smoothest flow and the least resistance—that is, through the mud return and chip discharge port of the hollow mandrel of the new drill bit, into the inner hole of the hollow mandrel, and then into the inner hole channel of the inner and outer double channel drill pipe to form a high-speed backflow. Finally, it is discharged from the body through the inner hole channel of the main spindle of the inner and outer double channel drilling rig.

[0055] Analysis of chip removal effect: Taking the current domestic medium-sized horizontal directional drilling rigs as an example: the conventional configuration of the mud pump of the representative medium-sized model is a maximum flow rate of 600L / min = 10L / s; the grouting pressure at the maximum flow rate is 2~3 MPa, which is equivalent to a head of 200~300M; and a new type of internal and external double-channel drill rod with an outer diameter of 114mm is used, with an inner channel diameter of 70mm.

[0056] The drill pipe has a 70mm inner bore with a volume of 3.8L per meter. Assuming a grouting flow rate of 10L / s and 80% of the flow forming internal backflow, the backflow velocity can reach 2.1 m / s. Under this velocity condition, drill cuttings cannot settle inside the pipe. The semi-enclosed functional chamber inside the drill bit rotates continuously during hole drilling, further eliminating the possibility of drill cuttings settling. Even if only 20% of the grouting pressure remains after backflow, it is still sufficient.

[0057] This analysis shows that the new type of horizontal directional drilling rig adopts a closed-loop slurry return and chip removal system, which can achieve basically complete chip removal during the hole formation process.

[0058] Engineering effect analysis: The table below compares the matching drilling rig power, torque, and number of drilling stages for two processes: insufficient chip removal and complete chip removal, when drilling holes of different diameters.

[0059]

[0060] Note: Reverse drilling creates a hole from the bottom up, and the drill cuttings fall directly under their own weight, posing almost no resistance to the rotation and cutting of the drill bit. Comparison with data from reverse drilling demonstrates that if horizontal directional drilling achieves complete cuttings removal, existing drilling rig torque configurations can all achieve hole formation in a single pass.

[0061] The technical effects achieved by this invention are as follows: This invention provides a novel closed-loop slurry return and cuttings removal horizontal directional drilling rig, which can achieve more thorough removal of drill cuttings, greatly reduce torque loss during drilling, and thus significantly increase the diameter of the hole formed in one operation. This enables the horizontal directional drilling rig to achieve one-time hole formation for most pipeline laying operations, thereby reducing the construction cost and construction period of the hole formation stage by several times.

[0062] This invention significantly reduces the number of process steps, eliminates the need for personnel to move drill rods between entry and exit points and to connect drill rods, and greatly reduces labor intensity.

[0063] This invention achieves a closed-loop mud-water circulation, enabling more efficient recycling of mud, reducing mud consumption, and minimizing environmental pollution.

[0064] This invention realizes a closed-loop slurry return and chip removal borehole enlargement process. For formations with poor porosity, such as gravel and pebble formations, a high-power drilling rig can be used to complete the borehole formation and pipe pulling in one go, without worrying about the borehole collapse that occurs in traditional directional drilling, thus greatly reducing the engineering risks in harsh geological conditions. Example 2

[0065] This embodiment provides an alternative to the internal and external dual-channel drill pipe of the embodiment: such as Figure 6 and Figure 7 As shown, the inner and outer double-channel drill rod 2 is composed of an inner tube 11 and an outer tube 12. The inner tube 11 is held and fixed in the center of the inner hole of the outer tube 12 by a support frame, dividing the internal space of the outer tube 12 into two channels: an inner tube hole 38 and a double-wall sandwich layer 39 between the outer wall of the inner tube 11 and the inner wall of the outer tube 12. These channels serve as the inner hole channel and the outer layer channel of the inner and outer double-channel drill rod 2, respectively. The two ends of the outer tube 12 are respectively provided with a matching male threaded connector 40 and a female threaded connector 41. The two ends of the inner tube body are respectively provided with a matching male threaded connector 42 and a female threaded connector 43. The male threaded connector 40 and the female threaded connector 43 are arranged in the same direction. Example 3

[0066] This embodiment provides an alternative to a novel drill bit for the embodiment: such as Figure 8-10 As shown, the novel drill bit 3 is composed of a hollow mandrel 29 and a drill bit body 44. The drill bit body 44 has a hollow cylindrical structure, with a cutting disk 24 at the soil-facing end. Several cutting tools 30 and several mud injection nozzles 31 are arranged on the outer side of the cutting disk 24. The hollow mandrel 29 is located at the center of the cutting disk 24 and extends into the interior of the drill bit body 44. The section of the hollow mandrel 29 located on the outer side of the cutting disk 24 has a double-channel structure, with an outer hollow mandrel channel 33 and an inner hollow mandrel hole. Channels 34 serve as the outer channel and inner channel of the new drill bit 3, respectively; the outer channel 33 of the hollow mandrel extends to the connection with the cutting disk 24, and the inner channel 34 of the hollow mandrel extends into the drill bit body 44; the outer channel 33 of the hollow mandrel is connected to the mud injection port 31 through the grouting pipe 35; the cutting disk 24 is provided with multiple chip inlets 36; the shaft wall section of the hollow mandrel 29 inside the drill bit body 44 has a return slurry and chip discharge port 37 leading to the inner channel 34 of the hollow mandrel. Example 4

[0067] This embodiment provides another alternative to a novel drill bit for the embodiment: such as Figure 11-13 As shown, the novel drill bit 3 is composed of a hollow mandrel 29 and a roller cone drill bit 45. The end of the hollow mandrel 29 is fixedly connected to the roller cone drill bit 45, and the soil-facing end of the roller cone drill bit 45 is provided with a plurality of cutting roller cones 46. The hollow mandrel 29 has a double-channel structure, with an outer hollow mandrel channel 33 and an inner hollow mandrel channel 34, which serve as the outer channel and inner channel of the novel drill bit 3, respectively. The shaft wall of the hollow mandrel 29 is provided with a mud injection port 31 leading to the outer hollow mandrel channel 33 and a return mud and chip removal port 37 leading to the inner hollow mandrel channel 34.

[0068] The above description is merely a preferred embodiment of the present invention. It should be noted that those skilled in the art can make various improvements and modifications without departing from the principles of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention. Structures, devices, and operating methods not specifically described or explained in this invention are implemented according to conventional methods in the art unless otherwise specified or limited.

Claims

1. A new type of horizontal directional drilling machine with closed slurry return and chip removal, which is composed of an inner-outer dual-channel drilling machine main machine, an inner-outer dual-channel drilling rod and a new type of drill bit, characterized in that: The inner and outer double-channel drilling machine main machine power head main shaft, the inner and outer double-channel drill pipe and the new drill bit core shaft are provided with inner hole channel and outer layer channel; the core shaft wall of the new drill bit is provided with a slurry return and cutting discharge port leading to the inner hole channel, and the new drill bit is provided with a mud injection port; during drilling machine operation, mud is injected from the outer layer channel of the inner and outer double-channel drilling machine main machine, and is sprayed from the mud injection port of the new drill bit through the outer layer channel of the inner and outer double-channel drill pipe to the outer layer channel of the new drill bit core shaft, the sprayed mud is mixed with drill cuttings, enters the inner hole channel of the core shaft from the slurry return and cutting discharge port of the new drill bit core shaft, and is returned through the inner hole channel of the double-channel drill pipe until it is discharged from the inner hole channel of the main machine.

2. A closed slurry return and chip removal horizontal directional drilling machine as claimed in claim 1, wherein: The inner hole channel and the outer layer channel of the inner and outer double-channel drilling machine main machine are respectively composed of a main shaft center channel inside the power head main shaft of the drilling machine main machine and a main shaft outer layer channel.

3. A closed slurry return and chip removal horizontal directional drilling machine as claimed in claim 1, wherein: The inner hole channel and the outer layer channel of the inner and outer double-channel drill pipe are respectively composed of an inner tube of the drill pipe body and an annular cavity between the inner tube and an outer tube.

4. A closed slurry return and chip removal horizontal directional drilling machine as claimed in claim 1, wherein: The inner and outer double-channel drill pipe is composed of an inner tube and an outer tube, the inner tube is fixed in the center of the inner hole of the outer tube by a support frame, and the inner tube divides the internal space of the outer tube into an inner tube hole and a double-wall sandwich between the outer wall of the inner tube and the inner wall of the outer tube, which are respectively used as the inner hole channel and the outer layer channel of the inner and outer double-channel drill pipe; the two ends of the outer tube are respectively provided with a male threaded joint and a female threaded joint; the two ends of the inner tube body are respectively provided with a male threaded joint and a female threaded joint.

5. A closed slurry return chip removal novel horizontal directional drilling machine as claimed in any one of claims 1 to 4 wherein: The new drill bit is composed of a cutting disc and a drill bit seat, the drill bit seat is a pressure maintaining cylinder body rolled from a steel plate, a vertical plate is welded and fixed in the pressure maintaining cylinder body, a core shaft seat is fixedly installed at the center of the vertical plate, a hollow core shaft extending towards the earth is rotatably and fixedly installed in the core shaft seat, the cutting disc is fixedly installed at the earth-facing end of the hollow core shaft, and the earth-facing surface of the cutting disc is provided with a plurality of cutting tools and a plurality of mud injection ports; the cutting disc, the vertical plate of the drill bit seat and the pressure maintaining cylinder body form a drill cuttings storage cabin; a section of the hollow core shaft outside the cutting disc is a double-channel structure, and is provided with a hollow core shaft outer layer channel and a hollow core shaft inner hole channel, which are respectively used as the outer layer channel and the inner hole channel of the new drill bit; the hollow core shaft outer layer channel extends to the connection position with the cutting disc, and the hollow core shaft inner hole channel extends into the drill cuttings storage cabin; the hollow core shaft outer layer channel is communicated with the mud injection port through a mud injection pipe; the cutting disc is provided with a plurality of cutting entry ports; the shaft wall section of the hollow core shaft in the drill cuttings storage cabin is provided with a slurry return and cutting discharge port leading to the hollow core shaft inner hole channel.

6. A closed slurry return chip removal novel horizontal directional drilling machine as claimed in any one of claims 1 to 4 wherein: The new drill bit is composed of a hollow core shaft and a drill bit body, the drill bit body is a hollow cylinder structure, the cutting disc is arranged at the earth-facing end, a plurality of cutting tools and a plurality of mud injection ports are arranged outside the cutting disc, the hollow core shaft is arranged at the center of the cutting disc and extends into the inside of the drill bit body, the hollow core shaft is provided with a hollow core shaft outer channel and a hollow core shaft inner hole channel, and the hollow core shaft outer channel and the hollow core shaft inner hole channel are respectively used as an outer channel and an inner hole channel of the new drill bit, the hollow core shaft outer channel extends to the connection position of the cutting disc, and the hollow core shaft inner hole channel extends to the inside of the drill bit body, the hollow core shaft outer channel is communicated with the mud injection port through a grouting pipe, the cutting disc is provided with a plurality of chip inlets, and the shaft wall of the hollow core shaft in the drill bit body is provided with a mud return and chip removal port connected to the hollow core shaft inner hole channel.

7. A closed slurry return chip removal novel horizontal directional drilling machine as claimed in any one of claims 1 to 4 wherein: The new drill bit is composed of a hollow core shaft and a roller bit, the end of the hollow core shaft is fixedly connected with the roller bit, and the earth-facing end of the roller bit is provided with a plurality of cutting rollers; the hollow core shaft is provided with a hollow core shaft outer channel and a hollow core shaft inner hole channel, and the hollow core shaft outer channel and the hollow core shaft inner hole channel are respectively used as an outer channel and an inner hole channel of the new drill bit; the shaft wall of the hollow core shaft is respectively provided with a mud injection port connected to the hollow core shaft outer channel and a mud return and chip removal port connected to the hollow core shaft inner hole channel.

8. A closed slurry return chip removal novel horizontal directional drilling machine as claimed in claim 2, wherein: The main shaft center hole of the power head main shaft of the inner-outer double-channel drilling machine main machine penetrates front and back, is a mud return and chip removal channel, and the rear end is provided with a rotary water sealing interface used for connecting a mud return pipe.

9. A closed slurry return chip removal novel horizontal directional drilling machine as claimed in claim 2 wherein: The main shaft outer channel is arranged at the part of the power head main shaft of the inner-outer double-channel drilling machine main machine that protrudes forward, the rear end of the main shaft outer channel is provided with a plurality of radial grouting holes, the radial grouting holes are communicated with the main shaft outer channel, and an annular rotary water sealing interface used for connecting a grouting pipe is arranged at the shaft section of the radial grouting holes.

10. A closed slurry return chip removal novel horizontal directional drilling machine as claimed in claim 2, wherein: The front end of the power head main shaft of the inner-outer double-channel drilling machine main machine is provided with a joint connected with the inner-outer double-channel drill rod.

11. A closed slurry return chip removal novel horizontal directional drilling machine as claimed in claim 3 wherein: The root of the male joint body is provided with a sealing ring groove, and a sealing ring is arranged in the sealing ring groove; after the female joint body of another drill rod is connected, the end wall of the female joint body and the sealing ring of the root of the male joint body are in a compressed state, thereby forming sealing between the outer channel of the drill rod and the outside; a thread end of the male joint body is provided with an extension section with the same diameter as the thread part, a corresponding sealing hole is arranged in the female joint body, a sealing ring groove is arranged on the circumference of the extension section, and a sealing ring is arranged in the sealing ring groove; when the two drill rods are threadedly connected, the extension section of the male joint body is inserted into the sealing hole in the female joint body, thereby forming sealing between the outer channel of the drill rod and the central channel of the drill rod.

12. A closed slurry return chip removal novel horizontal directional drilling machine as claimed in claim 4 wherein: The male threaded joint of the outer pipe body and the female threaded joint of the inner pipe body are arranged in the same direction.

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