A dual-path hydraulic fracturing device and method for steeply inclined coal seams

Abstract

The present invention discloses a dual-path hydraulic fracturing device and method for steeply inclined coal seams, and relates to the technical field of underground hydraulic fracturing. The device comprises a guide head, a positioning part is arranged at the bottom end of the guide head, a positioning assembly is arranged at the middle part of the positioning part, a first connecting part is arranged at the bottom of the positioning part, and a second connecting part is arranged at the bottom end of the first connecting part. The dual-path hydraulic fracturing device for steeply inclined coal seams is used to adjust the injection angle of the injection assembly by arranging a rotating assembly, so as to perform multi-position fracturing on the fracture layer. When the top barrel is lifted upward by the external high-pressure push rod, the slider provided on the outer extension ring of the top barrel moves along the spiral groove provided on the inner side wall of the third connecting part. At this time, the third connecting part performs a circular motion at a certain angle under the extrusion of the slider, so as to realize the deflection of the hydraulic injection head.

Description

Technical Field

[0001] The invention relates to the technical field of underground hydraulic fracturing, and in particular to an underground dual-path hydraulic fracturing device and method for steeply inclined coal seams. Background Art

[0002] Coal is the main energy source in my country, accounting for about 66% of the primary energy consumption. In the western region, 80% of the mining areas have steeply inclined coal seams. When the coal seam inclination reaches more than 45°, the gas extraction tunnel is designed according to the rectangular section, and the tunnel height will reach more than 5m, which is not conducive to the relocation of gas extraction equipment and the adjustment of the inclination. In addition, my country's coal seams generally have poor permeability. Improving the permeability of coal seams is one of the key issues that need to be urgently solved in coalbed methane mining at home and abroad.

[0003] The hydraulic permeability enhancement method refers to a method of using high-pressure water as a medium and power for fracturing and crushing, including hydraulic fracturing, hydraulic cutting, hydraulic punching, etc. The hydraulic permeability enhancement method requires the use of a fracturing device to inject high-pressure water into the coal seam to achieve coal seam fracturing. At present, the pre-cracking radius of the single coal seam hydraulic cutting technology is small, and the effect of the single coal seam hydraulic fracturing technology is poor, and it requires continuous adjustment and the working state of the device, and cannot achieve multi-channel synchronous and independent operation. At the same time, the existing jet water flow for steep coal seams is difficult to achieve directional cutting and a certain range of fracturing for the coal seam at the same time. Summary of the invention

[0004] 1. Technical issues to be resolved

[0005] In view of the shortcomings of the prior art, the present invention provides a dual-path hydraulic fracturing device and method for steeply inclined coal seams underground, which solves the problems that the existing fracturing devices have single functions, cumbersome operations, and cannot achieve multi-path synchronous and independent operation. At the same time, the existing jet water flow is difficult to achieve directional cutting and a certain range of fracturing of the coal seam at the same time.

[0006] (II) Technical solution

[0007] To achieve the above objectives, the present invention is implemented through the following technical solutions: a dual-path hydraulic fracturing device for steeply inclined coal seams, comprising a guide head, a positioning portion is provided at the bottom end of the guide head, a positioning assembly is provided in the middle of the positioning portion, a first connecting portion is provided at the bottom of the positioning portion, a second connecting portion is provided at the bottom end of the first connecting portion, a steel ring is provided at the outer side of the second connecting portion, a plugging assembly is provided at the bottom end of the steel ring, a drag ring is provided at the bottom end of the plugging assembly, a third connecting portion is movably provided at the bottom end of the drag ring, a spraying assembly is provided in the middle of the third connecting portion, a liquid guide tube is inserted in the middle of the third connecting portion, a hydraulic top cylinder is sleeved on the outer side of the liquid guide tube, a rotating assembly is provided on the top of the hydraulic top cylinder, the rotating assembly is used in conjunction with the third connecting portion, an expansion connector is provided at one end of the liquid guide tube, and the expansion connector is used in conjunction with the plugging assembly.

[0008] Furthermore, the positioning assembly includes a square hole, an external ratchet, a spring tube, and an inverted cone, wherein the square holes are circumferentially equidistantly arranged on the outside of the positioning portion, the external ratchet is movably mounted on the inside of the square hole, the spring tube is fixedly mounted on the inner top wall of the positioning portion, and the inverted cone is fixedly connected to the bottom end of the spring tube, wherein the inverted cone is plugged into a block on the inner wall of the positioning portion.

[0009] Furthermore, the positioning assembly also includes a sealing column, a limit spring, a sealing plug, and a sealing cavity. The sealing cavity is opened in the middle of the first connecting part, the sealing column is fixedly installed on the inner wall of the sealing cavity, the sealing plug is movably installed on the inner wall of the sealing cavity, the limit spring is arranged on the top of the sealing plug, and the other end of the limit spring is fixedly connected to the bottom of the block on the inner wall of the positioning part.

[0010] Furthermore, a right-angle hole is opened in the middle of the first connecting part, the right-angle hole is connected to the sealing cavity, a spring sealing plug is fixedly installed on the inner wall of the right-angle hole, and the spring sealing plug is fitted with the right-angle part of the right-angle hole.

[0011] Furthermore, the sealing assembly includes an expansion connector, a sealing member, and a fluid guide tube, wherein the expansion connector is fixedly mounted at the bottom end of the second connecting portion, and the sealing member is sleeved on the outside of the expansion connector, wherein the two ends of the sealing member are respectively fixedly connected to the inner ends of the steel ring and the drag ring, and the sealing member is made of rubber material.

[0012] Furthermore, the injection assembly includes a cross conduit and a hydraulic injection head, the hydraulic injection head is fixedly installed on the inner wall of the third connecting part, the cross conduits are fixedly connected to the hydraulic injection heads respectively, and the cross conduits are externally connected to a high-pressure water injection pipe.

[0013] Furthermore, the rotating assembly includes a top cylinder, a return spring, a limit ring, and a spiral groove. The top cylinder is movably mounted on the inner wall of the third connecting part, the limit ring is fixedly mounted on the inner wall of the third connecting part, one end of the return spring is fixedly mounted on the bottom of the limit ring, the other end of the return spring is fixedly connected to the top end of the top cylinder, and the spiral groove is opened on the inner wall of the third connecting part.

[0014] Furthermore, an extension ring is provided at the top of the top cylinder, the extension ring is fitted with the inner wall of the third connecting portion, a sliding block is provided on the side of the extension ring, and the sliding block is movably connected to the spiral groove.

[0015] Furthermore, a spherical groove is provided in the middle of the second connecting part, a sealing bead is movably mounted on the inner wall of the spherical groove, a spring is provided on the outer side of the sealing bead, and a circular hole is provided at the bottom of the second connecting part, which is connected to the spherical groove.

[0016] A coal seam downhole fracturing method applied to a steeply inclined coal seam downhole dual-path hydraulic fracturing device comprises the following steps:

[0017] S1. Understand the mine conditions to be collected, including the stratum conditions, mine field structure conditions, coal seam conditions and gas conditions;

[0018] S2. Drill holes into the ground and determine the number and depth of holes according to the construction plan;

[0019] S3, sending the hydraulic fracturing device into the borehole through a high-pressure push rod, and injecting high-pressure water into the plugging component in the device to seal the water injection port to ensure the sealing effect;

[0020] S4, then connect several groups of high-pressure water pipes to the device. When the lines are connected, start the water injection pump, and high-pressure water is injected into the fracturing borehole through the injection assembly. After the high-pressure water fills each borehole fracturing section, the internal pressure performs hydraulic fracturing on the coal seam;

[0021] S5. Use the drilling rig to withdraw the high-pressure push rod together with the fracturing device to the next fracturing point, start the automatic control system and the high-pressure pump station again, and fractur the second fracturing point. After the fracturing of the second fracturing point is completed, withdraw to the third fracturing point again to complete all staged fracturing of all boreholes.

[0022] (III) Beneficial effects

[0023] The present invention has the following beneficial effects:

[0024] 1. The underground dual-path hydraulic fracturing device for steeply inclined coal seams is used to adjust the injection angle of the injection assembly by arranging a rotating component, so as to perform multi-position fracturing on the fracture layer of the steeply inclined coal seam. The top cylinder is used to drive the third connecting part. When the top cylinder is lifted upward by the action of the external high-pressure push rod, the slider provided on the outer extension ring of the top cylinder will move along the spiral groove provided on the inner side wall of the third connecting part. At this time, the third connecting part makes a circular motion at a certain angle under the extrusion of the slider, so as to realize the deflection of the hydraulic jet head.

[0025] 2. The dual-path hydraulic fracturing device for steeply inclined coal seams underground, the expansion connector in the plugging assembly is used to convey high-pressure water flow, so that it expands the packing and fits the inner wall of the coal seam to complete the plugging of the borehole, the liquid guide tube is used to connect with the expansion connector, the other end of the liquid guide tube is externally connected to a mobile high-pressure hydraulic pump station to convey high-pressure water flow to the device, the spherical groove provided in the second connecting part is used to control the discharge of the high-pressure water flow in the middle of the packing, the circular hole provided at the bottom of the second connecting part is connected to the gap formed between the packing and the second connecting part, when the high-pressure water flow conveyed in the expansion connector squeezes the sealing beads, the sealing beads shrink to the inside of the spherical groove, at this time the water flows through the circular hole into the gap formed between the packing and the second connecting part, with the entry of the water flow, the packing expands to seal the borehole.

[0026] Of course, any product implementing the present invention does not necessarily need to achieve all of the advantages described above at the same time. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 It is a three-dimensional schematic diagram of a dual-path hydraulic fracturing device for steeply inclined coal seams in the present invention;

[0028] Figure 2 It is a cross-sectional schematic diagram of the hydraulic fracturing device of the present invention;

[0029] Figure 3 It is a schematic diagram of the structure of the packing member in the present invention;

[0030] Figure 4 This is a schematic diagram of the structure of the first connecting part in the present invention;

[0031] Figure 5 It is a schematic diagram of the structure of the sealing member, the second connecting part, the liquid guiding tube, and the expansion connecting member in the present invention;

[0032] Figure 6 It is a schematic cross-sectional view of the structure of the first connecting part, the sealing member and the third connecting part in the present invention;

[0033] Figure 7 For the present invention Figure 6 A schematic diagram of the enlarged structure of the middle part A;

[0034] Figure 8 It is a schematic diagram of the structure of the top tube and the third connecting part in the present invention;

[0035] Fig. 9 It is a partial cross-sectional schematic diagram of the third connecting portion structure in the present invention;

[0036] Fig.10 It is a schematic diagram of the cross-duct structure in the present invention;

[0037] Fig.11 It is a schematic diagram of the third connecting part and the hydraulic jack structure in the present invention.

[0038] In the figure, 1. guide head; 2. positioning part; 3. square hole; 4. external ratchet; 5. first connecting part; 6. steel ring; 7. second connecting part; 8. sealing part; 9. third connecting part; 10. hydraulic jet head; 11. spring cylinder; 12. inverted cone; 13. sealing column; 14. limiting spring; 15. sealing plug; 16. sealing chamber; 17. expansion connector; 18. reset spring; 19. top cylinder; 20. liquid guide tube; 21. right-angle hole; 22. spring sealing plug; 23. slider; 24. spiral groove; 25. limiting ring; 26. cross guide tube; 27. drag ring; 28. hydraulic top cylinder; 29. ​​spherical groove; 30. sealing bead. DETAILED DESCRIPTION

[0039] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0040] In the description of the present invention, it should be understood that the terms "opening", "upper", "lower", "thickness", "top", "middle", "length", "inside", "all around" and the like indicating orientation or positional relationship are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the components or elements referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as limiting the present invention.

[0041] See also Figure 1-11The embodiment of the present invention provides a technical solution: a dual-path hydraulic fracturing device for steeply inclined coal seams underground, comprising a guide head 1, a positioning portion 2 is provided at the bottom end of the guide head 1, a positioning assembly is provided in the middle of the positioning portion 2, a first connecting portion 5 is provided at the bottom of the positioning portion 2, a second connecting portion 7 is provided at the bottom end of the first connecting portion 5, a steel ring 6 is provided on the outer side of the second connecting portion 7, a plugging assembly is provided at the bottom end of the steel ring 6, a drag ring 27 is provided at the bottom end of the plugging assembly, a third connecting portion 9 is movably provided at the bottom end of the drag ring 27, an injection assembly is provided in the middle of the third connecting portion 9, a liquid guide tube 20 is inserted in the middle of the third connecting portion 9, a hydraulic top cylinder 28 is sleeved on the outer side of the liquid guide tube 20, a rotating assembly is provided on the top of the hydraulic top cylinder 28, the rotating assembly is used in conjunction with the third connecting portion 9, an expansion connector 17 is provided at one end of the liquid guide tube 20, and the expansion connector 17 is used in conjunction with the plugging assembly.

[0042] Specifically, the positioning assembly includes a square hole 3, an external ratchet 4, a spring tube 11, and an inverted cone 12. The square holes 3 are circumferentially equidistantly arranged on the outside of the positioning portion 2, the external ratchet 4 is movably installed on the inside of the square hole 3, the spring tube 11 is fixedly installed on the inner top wall of the positioning portion 2, and the inverted cone 12 is fixedly connected to the bottom end of the spring tube 11, wherein the inverted cone 12 is plugged into a block on the inner wall of the positioning portion 2.

[0043] In this embodiment, a positioning assembly is provided to position the entire fracturing device so that it can be snap-fitted with the inner wall of the borehole to ensure the positioning of the entire device, wherein the square hole 3 provided on the outer side of the positioning portion 2 is used to install the external ratchet 4, and an installation cavity is provided in the middle of the positioning portion 2, the installation cavity is connected with the square hole 3, wherein the shape of the external ratchet 4 is trapezoidal, one side of the external ratchet 4 is inclined, a metal column extends from the top end of the inverted cone 12, the metal column is plugged into the inner wall of the spring cylinder 11, the top end of the inverted cone 12 is squeezed with the bottom end of the external ratchet 4, wherein the gap between the external ratchet 4 from the bottom end to the top end gradually decreases;

[0044] When the inverted cone 12 moves upward, the top of the inverted cone 12 will squeeze the inner side of the outer ratchet 4. At this time, the inverted cone 12 will make a linear outward expansion movement along the inner wall of the square hole 3 under the action of the squeezing force, thereby realizing the clamping connection between the outer side of the outer ratchet 4 and the coal seam borehole. When the inverted cone 12 moves to the maximum position, the spring inside the spring tube 11 is squeezed and is in a fully compressed state. When the squeezing force on the spring disappears, the inverted cone 12 resets downward under the action of the elastic potential energy of the spring.

[0045] Specifically, the positioning assembly also includes a sealing column 13, a limiting spring 14, a sealing plug 15, and a sealing cavity 16. The sealing cavity 16 is opened in the middle of the first connecting part 5. The sealing column 13 is fixedly installed on the inner wall of the sealing cavity 16. The sealing plug 15 is movably installed on the inner wall of the sealing cavity 16. The limiting spring 14 is arranged on the top of the sealing plug 15. The other end of the limiting spring 14 is fixedly connected to the bottom of the block on the inner wall of the positioning part 2.

[0046] In the present embodiment, a sealing column 13 is provided to seal the sealing cavity 16, thereby forming a closed area of ​​the sealing cavity 16 at the bottom of the sealing plug 15 and the top area of ​​the sealing column 13, wherein the limit spring 14 provided at the top of the sealing plug 15 is used to reset the sealing plug 15, and by injecting a high-pressure water flow into the sealing cavity 16, the pressure inside the sealing cavity 16 increases, and the sealing plug 15 moves upward along the inner wall of the sealing cavity 16 under pressure, and the sealing plug 15 squeezes the inverted cone 12 to trigger the positioning component, so that it expands outward and fits and positions itself against the inner wall of the coal seam borehole, and a sealing plug is sleeved on the outside of the sealing plug 15, thereby ensuring the sealing of the sealing plug 15 and the inner wall of the sealing cavity 16, and the limit spring 14 provided at the top of the sealing plug 15 resets the sealing plug 15 downward under the action of its own elastic potential energy when the extrusion force applied to it disappears.

[0047] Specifically, a right-angle hole 21 is opened in the middle of the first connecting portion 5 , the right-angle hole 21 is connected to the sealing cavity 16 , a spring sealing plug 22 is fixedly installed on the inner wall of the right-angle hole 21 , and the spring sealing plug 22 fits the right angle part of the right-angle hole 21 .

[0048] In this embodiment, a right-angle hole 21 is provided in the middle of the first connecting portion 5 for conveying high-pressure water flow. By conveying high-pressure water flow to the right-angle hole 21, the water flow enters the inside of the sealing cavity 16. As the water flow inside the sealing cavity 16 increases, the pressure gradually increases, thereby driving the sealing plug 15 to provide power for the expansion of the positioning component. The spring sealing plug 22 provided inside the right-angle hole 21 is used to block the discharge port of the right-angle hole 21, thereby ensuring that the high-pressure water flow inside the sealing cavity 16 will not be discharged. The spring sealing plug 22 and the discharge port of the right-angle hole 21 are The initial position is in a closed state. When the spring sealing plug 22 is squeezed by water, it will move upward and squeeze the spring, and the water will flow into the sealing chamber 16 along the discharge port. When the pressure on the spring sealing plug 22 disappears, it will reset under the action of the spring to seal the discharge port. When the pressure inside the sealing chamber 16 needs to be relieved, a low-pressure water flow containing steel balls is injected into the right-angle hole 21 to squeeze the spring sealing plug 22 and separate it from the discharge port. The water flow inside the sealing chamber 16 is discharged under the action of the water pressure difference, thereby releasing the support state of the positioning component.

[0049] Specifically, the plugging assembly includes an expansion connector 17, a sealing member 8, and a liquid guide tube 20. The expansion connector 17 is fixedly mounted at the bottom end of the second connecting portion 7, and the sealing member 8 is sleeved on the outside of the expansion connector 17. The two ends of the sealing member 8 are respectively fixedly connected to the inner ends of the steel ring 6 and the drag ring 27. The sealing member 8 is made of rubber material.

[0050] A spherical groove 29 is provided in the middle of the second connecting part 7 , a sealing bead 30 is movably mounted on the inner wall of the spherical groove 29 , a spring is provided on the outer side of the sealing bead 30 , and a circular hole is provided at the bottom of the second connecting part 7 , which is connected to the spherical groove 29 .

[0051] In this embodiment, a plugging assembly is provided to plug the inner wall of the coal seam borehole, thereby realizing the high-pressure water flow ejected by the injection assembly to fractur the coal seam. The expansion connector 17 in the plugging assembly is used to deliver the high-pressure water flow to expand the packing 8 and fit it to the inner wall of the coal seam to complete the plugging of the borehole. The liquid guide tube 20 is used to connect with the expansion connector 17. The other end of the liquid guide tube 20 is externally connected to a mobile high-pressure hydraulic pump station to deliver high-pressure water flow to the device. The spherical groove 29 provided in the second connection part 7 is used to control the high-pressure water flow in the middle of the packing 8. The circular hole at the bottom of the second connection part 7 is connected with the gap formed between the packing 8 and the second connection part 7. When the high-pressure water flow transported in the expansion connection part 17 squeezes the sealing bead 30, the sealing bead 30 shrinks to the inside of the spherical groove 29. At this time, the water flows through the circular hole into the gap formed between the packing 8 and the second connection part 7. With the entry of the water flow, the packing 8 expands to block the borehole. When the injection of the high-pressure water flow stops, the sealing bead 30 resets downward under the action of the spring to block the circular hole connected with the gap.

[0052] When it is necessary to relieve the pressure inside the sealing member 8, a low-pressure water flow containing steel balls is injected into the liquid guide tube 20 to squeeze the sealing beads 30 to separate them from the circular holes. The water flow in the gap is discharged under the action of the water pressure difference, thereby releasing the expansion state of the expansion component.

[0053] Specifically, the injection assembly includes a cross duct 26 and a hydraulic injection head 10. The hydraulic injection head 10 is fixedly mounted on the inner wall of the third connecting portion 9. The cross duct 26 is fixedly connected to the hydraulic injection head 10 respectively. The cross duct 26 is externally connected to a high-pressure water injection pipe.

[0054] In this embodiment, the water injection pipe connected to the cross conduit 26 is connected to a mobile high-pressure hydraulic pump station to transport high-pressure water flow, which is discharged through the hydraulic jet head 10. At this time, the high-speed sprayed water flow will fracture the coal seam.

[0055] Specifically, the rotating assembly includes a top cylinder 19, a return spring 18, a limit ring 25, and a spiral groove 24. The top cylinder 19 is movably mounted on the inner wall of the third connecting portion 9, the limit ring 25 is fixedly mounted on the inner side wall of the third connecting portion 9, one end of the return spring 18 is fixedly mounted on the bottom of the limit ring 25, and the other end of the return spring 18 is fixedly connected to the top of the top cylinder 19, and the spiral groove 24 is provided on the inner side wall of the third connecting portion 9;

[0056] An extension ring is provided at the top of the top tube 19 , and the extension ring is in contact with the inner wall of the third connecting portion 9 . A slider 23 is provided on the side of the extension ring, and the slider 23 is movably connected to the spiral groove 24 .

[0057] In this embodiment, a rotating assembly is provided to adjust the injection angle of the injection assembly, so as to perform multi-position fracturing on the fault layer, and the top cylinder 19 is used to drive the third connection part 9. When the top cylinder 19 is lifted upward by the external high-pressure push rod, the slider 23 provided on the outer extension ring of the top cylinder 19 will move along the spiral groove 24 provided on the inner wall of the third connection part 9. At this time, the third connection part 9 performs a circular motion at a certain angle under the extrusion of the slider 23. Since one end of the third connection part 9 is movably connected to the bottom end of the drag ring 27, the rotation of the third connection part 9 is realized to drive the hydraulic jet head 10 to deflect. When the top cylinder 19 is pressed to the maximum position, the reset spring 18 is squeezed and is in a fully compressed state. When the top pressure on the top cylinder 19 disappears, the top cylinder 19 is reset downward under the elastic potential energy of the reset spring 18, so that the third connection part 9 rotates in the opposite direction under the drive of the top cylinder 19, thereby resetting the injection position of the hydraulic jet head 10 to the initial state.

[0058] A coal seam downhole fracturing method applied to a steeply inclined coal seam downhole dual-path hydraulic fracturing device comprises the following steps:

[0059] S1. Understand the mine conditions to be collected, including the stratum conditions, mine field structure conditions, coal seam conditions and gas conditions;

[0060] S2. Drill holes into the ground and determine the number and depth of holes according to the construction plan;

[0061] S3, sending the hydraulic fracturing device into the borehole through a high-pressure push rod, and injecting high-pressure water into the plugging component in the device to seal the water injection port to ensure the sealing effect;

[0062] S4, then connect several groups of high-pressure water pipes to the device. When the lines are connected, start the water injection pump, and high-pressure water is injected into the fracturing borehole through the injection assembly. After the high-pressure water fills each borehole fracturing section, the internal pressure performs hydraulic fracturing on the coal seam;

[0063] S5. Use the drilling rig to withdraw the high-pressure push rod together with the fracturing device to the next fracturing point, start the automatic control system and the high-pressure pump station again, and fractur the second fracturing point. After the fracturing of the second fracturing point is completed, withdraw to the third fracturing point again to complete all staged fracturing of all boreholes.

[0064] It should be noted that, in this article, relational terms such as first and second, etc. are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the terms "include", "comprise" or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device.

[0065] The preferred embodiments of the present invention disclosed above are only used to help illustrate the present invention. The preferred embodiments do not describe all details in detail, nor do they limit the invention to only the specific embodiments described. Obviously, many modifications and changes can be made according to the content of this specification.

[0066] The present specification selects and specifically describes these embodiments in order to better explain the principles and practical applications of the present invention, so that those skilled in the art can better understand and utilize the present invention. The present invention is limited only by the claims and their full scope and equivalents.

Claims

1. A dual-path hydraulic fracturing device for steeply inclined coal seams, comprising a guide head (1), characterized in that: The bottom end of the guide head (1) is provided with a positioning portion (2), the middle part of the positioning portion (2) is provided with a positioning assembly, the bottom of the positioning portion (2) is provided with a first connecting portion (5), the bottom end of the first connecting portion (5) is provided with a second connecting portion (7), the outer side of the second connecting portion (7) is provided with a steel ring (6), the bottom end of the steel ring (6) is provided with a blocking assembly, the bottom end of the blocking assembly is provided with a drag ring (27), and the bottom end of the drag ring (27) is movably provided with a second connecting portion (5). Three connecting parts (9), the middle part of the third connecting part (9) is provided with a spray assembly, the middle part of the third connecting part (9) is plugged with a liquid guide tube (20), the outer side of the liquid guide tube (20) is sleeved with a hydraulic top cylinder (28), the top of the hydraulic top cylinder (28) is provided with a rotating assembly, the rotating assembly is used in conjunction with the third connecting part (9), one end of the liquid guide tube (20) is provided with an expansion connector (17), the expansion connector (17) is used in conjunction with the plugging assembly; The positioning assembly comprises a square hole (3), an outer ratchet (4), a spring tube (11), and an inverted cone (12); the square hole (3) is equidistantly arranged on the outer side of the positioning portion (2) in a circumferential manner; the outer ratchet (4) is movably mounted on the inner side of the square hole (3); the spring tube (11) is fixedly mounted on the inner top wall of the positioning portion (2); the inverted cone (12) is fixedly connected to the bottom end of the spring tube (11); and the inverted cone (12) is plugged into a stopper on the inner wall of the positioning portion (2); The rotating assembly comprises a top cylinder (19), a return spring (18), a limit ring (25), and a spiral groove (24); the top cylinder (19) is movably mounted on the inner wall of the third connecting portion (9); the limit ring (25) is fixedly mounted on the inner side wall of the third connecting portion (9); one end of the return spring (18) is fixedly mounted on the bottom of the limit ring (25); the other end of the return spring (18) is fixedly connected to the top end of the top cylinder (19); and the spiral groove (24) is provided on the inner side wall of the third connecting portion (9).

2. The dual-path hydraulic fracturing device for steeply inclined coal seams according to claim 1 is characterized in that: The positioning assembly also includes a sealing column (13), a limiting spring (14), a sealing plug (15), and a sealing cavity (16); the sealing cavity (16) is opened in the middle of the first connecting portion (5); the sealing column (13) is fixedly mounted on the inner wall of the sealing cavity (16); the sealing plug (15) is movably mounted on the inner wall of the sealing cavity (16); the limiting spring (14) is arranged on the top of the sealing plug (15); and the other end of the limiting spring (14) is fixedly connected to the bottom of the block on the inner wall of the positioning portion (2).

3. The dual-path hydraulic fracturing device for steeply inclined coal seams according to claim 1 is characterized in that: A right-angle hole (21) is provided in the middle of the first connecting portion (5), the right-angle hole (21) is communicated with the sealing cavity (16), a spring sealing plug (22) is fixedly mounted on the inner wall of the right-angle hole (21), and the spring sealing plug (22) fits in the right angle portion of the right-angle hole (21).

4. The dual-path hydraulic fracturing device for steeply inclined coal seams according to claim 1 is characterized in that: The plugging assembly comprises an expansion connector (17), a sealing member (8), and a fluid guide tube (20); the expansion connector (17) is fixedly mounted on the bottom end of the second connecting portion (7); the sealing member (8) is sleeved on the outside of the expansion connector (17); the two ends of the sealing member (8) are respectively fixedly connected to the inner ends of the steel ring (6) and the drag ring (27); and the sealing member (8) is made of rubber material.

5. The dual-path hydraulic fracturing device for steeply inclined coal seams underground according to claim 1 is characterized in that: The spray assembly comprises a cross conduit (26) and a hydraulic spray head (10), wherein the hydraulic spray head (10) is fixedly mounted on the inner wall of the third connecting portion (9), the cross conduit (26) is fixedly connected to the hydraulic spray head (10), and the cross conduit (26) is externally connected to a high-pressure water injection pipe.

6. The dual-path hydraulic fracturing device for steeply inclined coal seams underground according to claim 1 is characterized in that: An extension ring is provided at the top of the top cylinder (19), the extension ring is in contact with the inner wall of the third connecting portion (9), a slider (23) is provided on the side of the extension ring, and the slider (23) is movably connected to the spiral groove (24).

7. The dual-path hydraulic fracturing device for steeply inclined coal seams underground according to claim 1 is characterized by: A spherical groove (29) is provided in the middle of the second connecting portion (7), a sealing bead (30) is movably mounted on the inner wall of the spherical groove (29), a spring is provided on the outer side of the sealing bead (30), and a circular hole is provided at the bottom of the second connecting portion (7), the circular hole being connected to the spherical groove (29).

8. A fracturing method applied to the underground dual-path hydraulic fracturing device for steeply inclined coal seams as claimed in any one of claims 1 to 7, characterized in that: The following steps are involved: S1. Understand the mine conditions to be collected, including the stratum conditions, mine field structure conditions, coal seam conditions and gas conditions; S2. Drill holes into the ground and determine the number and depth of holes to be drilled according to the construction plan; S3, sending the hydraulic fracturing device into the borehole through a high-pressure push rod, and injecting high-pressure water into the plugging component in the device to seal the water injection port to ensure the sealing effect; S4, then connect several groups of high-pressure water pipes to the hydraulic fracturing device. When the lines are connected, start the water injection pump, and high-pressure water is injected into the fracturing borehole through the injection assembly. After the high-pressure water fills each borehole fracturing section, the internal pressure performs hydraulic fracturing on the coal seam; S5. Use the drilling rig to withdraw the high-pressure push rod together with the hydraulic fracturing device to the next fracturing point, start the automatic control system and the high-pressure pump station again, and fractur the second fracturing point. After the fracturing of the second fracturing point is completed, withdraw to the third fracturing point again to complete all staged fracturing of all boreholes.

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