Directional perforation and fracturing integrated device and method for coal mine

Abstract

The invention belongs to the technical field of coal mine underground hydraulic fracturing, and relates to a coal mine directional perforation and fracturing integrated device and method.The coal mine directional perforation and fracturing integrated device comprises a first packer, a dynamic sealing device, a one-way fracturing sliding sleeve, a directional perforator and a second packer which are sequentially connected and communicated from one end to the other end of the coal mine directional perforation and fracturing integrated device. Real integration of coal mine underground directional perforation and hydraulic fracturing procedures is achieved for the first time, the whole process of directional adjustment, perforation and fracturing is completed at a time through a single tubular column, the tedious operation that in a traditional technology, a drill rod needs to be pulled out and put down twice, and tools are repeatedly replaced is thoroughly eliminated, and the production efficiency is improved. The labor intensity of workers is remarkably reduced, the non-productive operation time is remarkably shortened, and the overall construction efficiency and economical efficiency of underground staged hydraulic fracturing are greatly improved.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of hydraulic fracturing in coal mines, and relates to a coal mine directional perforation and fracturing integrated device and method. BACKGROUND

[0002] With the rapid development of directional long borehole drilling technology in coal mines, the directional long borehole staged hydraulic fracturing technology has achieved remarkable application results in many engineering fields. This technology has unique advantages in regional modification pressure relief and anti-collision in thick and hard roof area, gas permeation extraction in low permeability coal seam, and top coal weakening to improve caving property, and provides important support for safe and efficient mining in coal mines. In the specific implementation process, directional perforation needs to be performed in some application scenarios in coal mines, and then hydraulic fracturing is implemented. The existing directional perforation and hydraulic fracturing process usually includes four main steps: first, a drill is used to drill a borehole to a designed depth; second, a directional perforation tool is lowered to a specified position in the borehole for perforation operation; after perforation is completed, the perforation device is withdrawn; and finally, a combined pipe column including a packer, a differential pressure sliding sleeve and the like is lowered to the perforation position, and hydraulic fracturing construction can be performed.

[0003] However, the current technology mode of separating perforation and fracturing construction has obvious disadvantages. Since the two key steps are performed independently, the drill pipe and supporting tools need to be lowered and lifted twice, which not only increases the repeated physical labor of workers, but also leads to a complicated construction process and low efficiency due to the need for manual positioning of the perforation point in a complex underground environment. The repeated tripping operation and complex operation directly lead to an increase in labor cost and time cost, which becomes a bottleneck restricting the further promotion and efficiency improvement of the technology.

[0004] In summary, the current perforation and hydraulic fracturing technology generally adopts a separate construction mode of first directional perforation and then fracturing. This mode leads to the artificial separation of directional perforation and fracturing steps, and the repeated lifting and lowering operation of the drill pipe and tools. In addition, the construction personnel also need to manually find the completed perforation point in a complex underground environment, and the whole construction process has many links, complex operation, high labor intensity, and finally leads to low operation efficiency and high labor cost. Therefore, it is urgent to explore a new method that can integrate the perforation and fracturing processes to simplify the operation process, reduce non-productive operation time, and effectively improve the overall economy and construction efficiency of the underground staged hydraulic fracturing technology. SUMMARY

[0005] Therefore, the purpose of the present application is to provide a coal mine directional perforation and fracturing integrated device and method to solve the problems in the background art.

[0006] To achieve the above-mentioned purpose, the present application provides the following technical solutions: The application discloses a coal mine directional perforation and fracturing integrated device. The one-way fracturing sliding sleeve comprises a fracturing sliding sleeve valve body, the fracturing sliding sleeve valve body is provided with a water diversion channel and a fracturing water flow channel, the water diversion channel is connected with the dynamic sealing device and the directional perforator respectively at two ends, the fracturing water flow channel is sealed at one end and connected with the directional perforator at the other end, and a plurality of fracturing sliding sleeve nozzles are radially arranged on the fracturing water flow channel. The directional perforator comprises a directional perforator inner tube, a directional perforator outer tube rotatably sleeved on the directional perforator inner tube and a driving pipe slidably arranged in the directional perforator outer tube, one end of the driving pipe is sleeved on the directional perforator inner tube and is connected with a directional perforator spring sleeved on the directional perforator inner tube in abutment, so that the driving pipe is provided with an elastic reset force. The one end of the driving pipe away from the directional perforator inner tube is provided with a tapered pressure-bearing water inlet, so that the driving pipe can be axially moved to compress the directional perforator spring under the action of high-pressure fluid pressure. The outer side of the directional perforator inner tube is provided with an annular directional runway, the annular directional runway is provided with an axial groove at the end away from the driving pipe, and a rolling directional ball is arranged on the annular directional runway, and the end of the driving pipe close to the directional perforator inner tube is provided with an annular cutter slot matched with the directional ball, so that the directional ball is moved into the axial groove on the annular directional runway when the driving pipe is moved, and the directional perforator inner tube and the one-way fracturing sliding sleeve are rotated, so that the directional perforation and fracturing integration is realized.

[0007] Further, the dynamic sealing device comprises a first dynamic sealing joint, a dynamic sealing body and a second dynamic sealing joint connected in sequence from one end to the other end, so that the first packer is not rotated with the one-way fracturing sliding sleeve.

[0008] Further, the first rigid sealing member and the second rigid sealing member are arranged at the connection of the first dynamic sealing joint and the second dynamic sealing joint and the dynamic sealing body respectively.

[0009] Further, the one-way fracturing sliding sleeve further comprises a one-way fracturing sliding sleeve rear joint connected at one end of the fracturing sliding sleeve valve body and a one-way fracturing sliding sleeve front joint connected at the other end.

[0010] Further, the spring seat is arranged at one end of the fracturing water flow channel close to the one-way fracturing sliding sleeve rear joint, the fracturing sliding sleeve spring is axially arranged on the spring seat, the valve ball is arranged at the end of the fracturing sliding sleeve spring away from the spring seat, so that the opening and closing of the fracturing sliding sleeve nozzle is controlled through the axial sliding of the valve ball.

[0011] Further, the driving tube is provided with a driving tube sealing ring in sealing sliding connection with the outer tube of the directional perforator at one end away from the inner tube of the directional perforator.

[0012] Further, a limiting ring is arranged outside the driving tube, and an axial limiting strip matched with the limiting ring is arranged on the outer tube of the directional perforator to limit the circumferential rotation of the driving tube.

[0013] Further, the outer tube of the directional perforator and the inner tube of the directional perforator are rotationally connected through a bearing, and the axial displacement of the inner tube of the directional perforator is limited through a shaft shoulder on the inner tube of the directional perforator.

[0014] Further, the outer tube of the directional perforator is connected to the inner cavity of the second packer to connect high-pressure water to the directional perforator.

[0015] Further, a plug is arranged at one end of the first packer away from the dynamic sealing device to achieve plugging of the coal mine directional perforation and fracturing integrated device close to the hole bottom.

[0016] Further, the device is arranged in multiple groups to form a coal mine directional perforation and fracturing tool string, and the coal mine directional perforation and fracturing tool string is plugged at one end close to the hole bottom through a plug to achieve distance multi-stage fracturing construction.

[0017] Further, the annular directional runway is a ring-shaped guide groove, and the directional ball falls into the axial groove under the pushing of the driving tube to keep the position of the axial groove facing the fixed design direction.

[0018] Further, the valve ball cannot be rushed open under the first water pressure state, and high-pressure water flows into the first packer through the water guide channel. Under the second water pressure state, the valve ball is rushed open, high-pressure water enters the fracturing water flow channel to achieve perforation and fracturing, and the first water pressure is less than the second water pressure.

[0019] In another aspect, the present application also provides a coal mine directional perforation and fracturing integrated method, which adopts the coal mine directional perforation and fracturing integrated device, and includes the following steps: The coal mine directional perforation and fracturing integrated device is connected to the drill pipe and pushed to the designated perforation position; High-pressure water is pumped, and the high-pressure water flows into the second packer, the directional perforator, the one-way fracturing sliding sleeve, the dynamic sealing device and the first packer in sequence; The second packer expands to plug the rear part of the drill hole in the fracturing zone, and the first packer expands to plug the front part of the drill hole in the fracturing zone. High-pressure water enters the drive tube of the directional perforator, pushing the drive tube to move axially, which in turn moves the directional ball on the annular directional track to the axial groove, thereby realizing the rotation of the inner tube of the directional perforator and the one-way fracturing sleeve, so that the fracturing sleeve nozzle faces the set direction, and the high-pressure water enters the first packer through the water inlet channel; Increase the water pressure, and high-pressure water enters the fracturing water flow channel, flows out from the fracturing sliding sleeve nozzle to form a high-pressure jet, perforates the coal seam, and continues to increase the pressure after perforation to achieve fracturing.

[0020] Furthermore, a spring seat is provided at one end of the fracturing water flow channel near the rear joint of the one-way fracturing sleeve, and a fracturing sleeve spring is axially arranged on the spring seat. A valve ball is arranged at the end of the fracturing sleeve spring away from the spring seat, so as to control the opening and closing of the fracturing sleeve nozzle by the axial sliding of the valve ball. After the water pressure is increased, the high-pressure water forces open the valve ball and enters the fracturing water flow channel.

[0021] Furthermore, before sending the integrated coal mine directional perforation fracturing device into the borehole, the angle between the fracturing sleeve nozzle in the unidirectional fracturing sleeve and the axial groove is adjusted to achieve directional perforation.

[0022] Furthermore, the method isolates the rotation of the first packer from the unidirectional fracturing sleeve through the dynamic sealing device, ensuring a stable sealing process.

[0023] Furthermore, the method connects multiple sets of the integrated coal mine directional perforation fracturing device to the drill pipe to enable fixed-distance multi-segment construction, which can be extended to multi-segment fracturing.

[0024] The beneficial effects of this invention are as follows: This invention is the first to achieve true integration of directional perforation and hydraulic fracturing processes in coal mines. The entire process of directional adjustment, perforation, and fracturing is completed in one go with a single tubing string, completely eliminating the cumbersome operations of raising and lowering the drill pipe twice and changing tools repeatedly in the traditional process. This significantly reduces the labor intensity of workers and the time spent on non-productive operations, and greatly improves the overall construction efficiency and economy of underground segmented hydraulic fracturing.

[0025] This invention creatively designs a high-pressure water-driven mechanical orientation mechanism. By cleverly cooperating with the drive tube, orientation ball, and circular track, it automatically completes the precise orientation adjustment of the nozzle during the pumping of high-pressure water. It can ensure that the perforation direction always faces the preset position without the need for an additional power source or downhole electronic instruments, achieving true "arbitrary in the well and accurate on the surface". This greatly improves the accuracy of perforation-guided fractures and the targeted nature of fracturing, making the engineering effects of depressurization of thick and hard roof, permeability enhancement of coal seams, and weakening of top coal more controllable and ideal.

[0026] The present application is compact in structure, reliable in action, can flexibly form a tool string by connecting multiple sets of devices in series, and can realize multi-section fixed-distance directional perforation and fracturing at one time of going down the well, and is particularly suitable for multi-section reconstruction requirements in long-distance directional drilling. Compared with the traditional separate process, the present application shortens the single-section construction time under the premise of ensuring fracturing effect, significantly improves the overall operation efficiency and safety level, provides an efficient, accurate and economic new technical means for hydraulic reconstruction in coal mine underground, and has strong engineering practicability and popularization value.

[0027] Other advantages, objects, and features of the present application will be apparent to those skilled in the art from the following specification, and will be learned from the practice of the present application. The objects and other advantages of the present application can be achieved and obtained by the following specification. BRIEF DESCRIPTION OF DRAWINGS

[0028] In order to make the objects, technical solutions and advantages of the present application clearer, the preferred detailed description of the present application will be made below in combination with the drawings, in which: Fig. 1 It is a schematic diagram of the overall structure of a coal mine directional perforation and fracturing integrated device in the embodiment; Fig. 2 It is a schematic diagram of the partial cross-sectional structure of a coal mine directional perforation and fracturing integrated device in the embodiment; Fig. 3 It is a schematic diagram of the structure of a driving pipe in the embodiment; Fig. 4 It is a schematic diagram of the partial structure of an inner pipe of a directional perforator in the embodiment.

[0029] Reference signs: 100 - plug, 200 - first packer, 300 - dynamic sealing device, 400 - one-way fracturing sliding sleeve, 500 - directional perforator, 600 - second packer; 2 - first dynamic sealing joint, 3 - first rigid sealing element, 4 - dynamic sealing body, 5 - second rigid sealing element, 6 - second dynamic sealing joint, 7 - one-way fracturing sliding sleeve rear joint, 8 - spring seat, 9 - fracturing sliding sleeve spring, 10 - fracturing sliding sleeve valve body, 101 - water diversion channel, 102 - fracturing water flow channel, 11 - fracturing sliding sleeve nozzle, 12 - valve ball, 13 - one-way fracturing sliding sleeve front joint, 14 - directional perforator inner pipe, 1401 - directional runway, 14011 - axial groove, 1402 - directional ball, 15 - bearing, 16 - directional perforator outer pipe, 17 - directional perforator spring, 18 - driving pipe, 1801 - driving pipe sealing ring, 1802 - conical pressure-bearing water inlet, 1803 - limiting ring, 1804 - annular cutting tooth groove. DETAILED DESCRIPTION

[0030] The following specific examples illustrate the implementation of the present invention. Those skilled in the art can easily understand other advantages and effects of the present invention from the content disclosed in this specification. The present invention can also be implemented or applied through other different specific embodiments, and various details in this specification can be modified or changed based on different viewpoints and applications without departing from the spirit of the present invention. It should be noted that the illustrations provided in the following embodiments are only schematic representations of the basic concept of the present invention. Unless otherwise specified, the following embodiments and features can be combined with each other.

[0031] The accompanying drawings are for illustrative purposes only and are schematic diagrams, not actual pictures. They should not be construed as limiting the invention. To better illustrate the embodiments of the invention, some parts in the drawings may be omitted, enlarged, or reduced, and do not represent the actual product dimensions. It is understandable to those skilled in the art that some well-known structures and their descriptions may be omitted in the drawings.

[0032] In the accompanying drawings of the embodiments of the present invention, the same or similar reference numerals correspond to the same or similar components. In the description of the present invention, it should be understood that if terms such as "upper," "lower," "left," "right," "front," and "rear" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings, they are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, the terms used to describe positional relationships in the drawings are only for illustrative purposes and should not be construed as limiting the present invention. For those skilled in the art, the specific meaning of the above terms can be understood according to the specific circumstances.

[0033] Example 1 Please see Figs. 1-4 This is an integrated directional perforation fracturing device for coal mines, mainly used for segmented fracturing of the top and bottom plates of coal seams. The perforation guides the fracturing fractures to penetrate the coal seam to achieve indirect extraction. This device can achieve perforation in a specific direction (generally downward) of the coal seam and can carry out fracturing without changing the device after perforation.

[0034] The integrated directional perforation fracturing device for coal mines includes a first packer 200, a dynamic sealing device 300, a unidirectional fracturing sliding sleeve 400, a directional perforator 500, and a second packer 600, which are connected and interconnected from left to right. The dynamic sealing device 300 includes a first dynamic sealing joint 2, a dynamic sealing body 4, and a second dynamic sealing joint 6 connected sequentially from left to right, and a first rigid sealing element 3 and a second rigid sealing element 5 are respectively provided at the connection between the first dynamic sealing joint 2 and the second dynamic sealing joint 6 and the dynamic sealing body 4. The one-way fracturing sliding sleeve 400 comprises a one-way fracturing sliding sleeve rear joint 7, a fracturing sliding sleeve valve body 10 and a one-way fracturing sliding sleeve front joint 13 connected in sequence from left to right, the fracturing sliding sleeve valve body 10 has a water guide channel 101 and a fracturing water flow channel 102, two ends of the water guide channel 101 are communicated with the dynamic sealing device 300 and the directional perforator 500 respectively, one end of the fracturing water flow channel 102 is sealed, the other end is communicated with the directional perforator 500, and a plurality of fracturing sliding sleeve nozzles 11 are radially arranged on the fracturing water flow channel 102; A spring seat 8 is arranged at one end of the fracturing water flow channel 102 close to the one-way fracturing sliding sleeve rear joint 7, the fracturing sliding sleeve spring 9 is arranged on the spring seat 8 in an axial direction, and the valve ball 12 is arranged at one end of the fracturing sliding sleeve spring 9 away from the spring seat 8, so as to control the opening and closing of the fracturing sliding sleeve nozzles 11 on the fracturing sliding sleeve valve body 10 through the axial sliding of the valve ball 12; The directional perforator 500 comprises a directional perforator inner tube 14, a directional perforator outer tube 16 rotatably sleeved on the directional perforator inner tube 14, and a driving tube 18, the driving tube 18 is arranged in the directional perforator outer tube 16 in a sliding manner, one end of the driving tube 18 is sleeved on the directional perforator inner tube 14, and the directional perforator spring 17 sleeved on the directional perforator inner tube 14 is connected to the driving tube 18 in a contact manner, the other end of the directional perforator spring 17 is fixedly connected to the directional perforator inner tube 14, so as to provide an elastic restoring force away from the directional perforator inner tube 14 to the driving tube 18; One end of the driving tube 18 away from the directional perforator inner tube 14 is provided with a driving tube sealing ring 1801 in a sealing sliding connection with the directional perforator outer tube 16, and the other end of the driving tube 18 away from the directional perforator inner tube 14 is provided with a tapered pressure-bearing water inlet 1802, so that the driving tube 18 can move axially under the pressure of high-pressure fluid when passing through the high-pressure fluid, and in turn compress the directional perforator spring 17 towards the directional perforator inner tube 14; A limiting ring 1803 is arranged on the outer side of the driving tube 18, and an axial limiting strip matched with the limiting ring 1803 is arranged on the directional perforator outer tube 16, so as to limit the circumferential rotation of the driving tube 18, so that the driving tube 18 can only move axially in the directional perforator outer tube 16, but cannot rotate circumferentially; An annular directional track 1401 is provided on the outer side of the inner tube 14 of the directional perforator. The end of the annular directional track 1401 away from the drive tube 18 has an axial groove 14011. A rolling directional ball 1402 is provided on the annular directional track 1401. The end of the drive tube 18 near the inner tube 14 of the directional perforator has an annular cutting tooth groove 1804 that matches the directional ball 1402. When the drive tube 18 moves toward the inner tube 14 of the directional perforator, the annular cutting tooth groove 1804 drives the directional ball 1402 to move in the axial groove 14011 through the annular directional track 1401, thereby driving the inner tube 14 of the directional perforator to rotate and driving the unidirectional fracturing sleeve 400 connected to the inner tube 14 of the directional perforator to rotate. Under the combined action of the directional ball 1402 and the annular directional track 1401, the position of the axial groove 14011 is kept facing the fixed design direction. Based on this, directional perforation can be achieved by adjusting the angle between the orientation of the fracturing sleeve nozzle 11 in the unidirectional fracturing sleeve 400 and the axial groove 14011 before the integrated directional perforation fracturing device for coal mine is lowered into the borehole.

[0035] The outer tube 16 and the inner tube 14 of the directional perforator are rotatably connected by a bearing 15, and the axial displacement of the inner tube 14 is restricted by a shoulder on the inner tube 14. The outer tube 16 of the directional perforator is connected to the inner cavity of the second packer 600 to allow high-pressure water to be introduced into the directional perforator 500.

[0036] Furthermore, a plug 100 is provided at the end of the first packer 200 away from the dynamic sealing device 300 to seal the end of the coal mine directional perforation fracturing integrated device near the bottom of the hole.

[0037] Specifically, the working principle of this integrated directional perforation fracturing device for coal mines is as follows: The coal mine directional perforation fracturing integrated device is connected to the drill rod and pushed to the designated perforation position to start pumping high-pressure water. The high-pressure water flows sequentially into the second packer 600, the directional perforator 500, the unidirectional fracturing sleeve 400, the dynamic sealing device 300, the first packer 200, and the plug 100. When the high-pressure water flows to the second packer 600, the second packer 600 first expands to seal the borehole at the rear of the fracturing zone; When water enters the drive pipe 18 of the directional perforator 500, the annular cutting groove 1801 on the drive pipe 18 stops the directional ball 1402 in the directional runway 1401 from moving. When the drive pipe 18 pushes the directional ball 1402 forward, the directional perforator inner pipe 14 rotates under the cooperation of the directional ball 1402 and the directional runway 1401, and the one-way fracturing sleeve 400 rotates. The directional runway 1401 on the directional perforator inner pipe 14 is provided with an axial groove 14011, so that the directional ball 1402 eventually falls into the axial groove 14011 under the push of the drive pipe 18, thereby ensuring that the fracturing sleeve nozzle 11 eventually points to the set direction regardless of its initial state. The one-way fracturing sleeve 400 is provided with a dynamic sealing device 300 at the front, so that the first packer 200 does not rotate with the one-way fracturing sleeve 400. When water flows from the drive pipe 18 into the directional perforator inner pipe 14 and then into the fracturing sleeve valve body 10, the water pressure is set to be small at this time, so the valve ball 12 cannot be flushed away. At this time, the water flow enters the water guide channel 101 of the fracturing sleeve valve body 10 and then flows into the first packer 200. The first packer 200 expands to block the front borehole of the fracturing zone, and at this time the fracturing section is blocked. As the water pressure increases and the plug 100 blocks, when the water pressure reaches a certain value, the high-pressure water flow flushes away the valve ball 12 and enters the fracturing water flow channel 102, and then flows out from a row of fracturing sleeve nozzles 11 to form a high-pressure beam. The high-pressure beam perforates the coal seam or the coal seam roof. When the perforation reaches a certain depth, the pressure continues to increase. Due to the blocking of the two packers, a large pressure is formed around the perforation, thereby achieving fracturing at the perforation.

[0038] Further, before the coal mine directional perforation and fracturing integrated device is sent into the borehole, the angle between the fracturing sleeve nozzle 11 in the one-way fracturing sleeve 400 and the axial groove 14011 is set to achieve directional perforation of the one-way fracturing sleeve.

[0039] Further, a plurality of coal mine directional perforation and fracturing integrated devices can be connected on the drill rod to form a coal mine directional perforation and fracturing tool string, and the end of the coal mine directional perforation and fracturing tool string close to the hole bottom is blocked by the plug 100, thereby realizing interval multi-section fracturing construction.

[0040] Embodiment 2 The embodiment provides a coal mine directional perforation and fracturing integrated method, which adopts the coal mine directional perforation and fracturing integrated device as described in Embodiment 1, and includes the following steps: Before sending the coal mine directional perforation and fracturing integrated device into the borehole, the angle between the fracturing sleeve nozzle 11 in the one-way fracturing sleeve 400 and the axial groove 14011 is adjusted to achieve directional perforation; The coal mine directional perforation and fracturing integrated device is connected to the drill pipe and pushed to the designated perforation position; High-pressure water is pumped in, which flows into the second packer 600, the directional perforator 500, the one-way fracturing sleeve 400, the dynamic sealing device 300, and the first packer 200 in sequence; After the second packer 600 expands to block the rear borehole of the fracturing zone, the first packer 200 expands to block the front borehole of the fracturing zone; High-pressure water enters the drive pipe 18 of the directional perforator 500, pushing the drive pipe 18 to move axially, driving the directional ball 1402 to move into the axial groove 14011 on the annular directional runway 1401, achieving the rotation of the directional perforator inner pipe 14 and the one-way fracturing sleeve 400, making the fracturing sleeve nozzle 11 face the set direction, and high-pressure water entering the first packer 200 through the water guide channel 101; The water pressure is increased, high-pressure water enters the fracturing water flow channel 102, and a high-pressure beam is formed from the fracturing sleeve nozzle 11, perforating the coal seam and continuing to increase the pressure to achieve fracturing after perforation; Wherein, a spring seat 8 is arranged at one end of the fracturing water flow channel 102 close to the one-way fracturing sleeve rear joint 7, a fracturing sleeve spring 9 is arranged axially on the spring seat 8, and a valve ball 12 is arranged at one end of the fracturing sleeve spring 9 away from the spring seat 8, so as to control the opening and closing of the fracturing sleeve nozzle 11 through the axial sliding of the valve ball 12; after increasing the water pressure, high-pressure water pushes away the valve ball 12 to enter the fracturing water flow channel 102; The method isolates the rotation of the first packer 200 and the one-way fracturing sleeve 400 through the dynamic sealing device 300, ensuring the stability of the blocking process.

[0041] Example 3 This embodiment provides an extended application of a coal mine directional perforation and fracturing integrated device, which is based on the coal mine directional perforation and fracturing integrated device described in Example 1. The device is arranged in multiple groups to form a coal mine directional perforation and fracturing tool string, and is blocked at one end close to the hole bottom through the plug 100 to achieve directional perforation and fracturing construction.

[0042] Specifically, the coal mine directional perforation and fracturing tool string is sequentially connected by at least two groups of coal mine directional perforation and fracturing integrated devices, each group of devices includes a first packer 200, a dynamic sealing device 300, a one-way fracturing sliding sleeve 400, a directional perforator 500 and a second packer 600, the groups are communicated through drill pipes or connecting pieces, and a plug 100 is arranged at the end of the first packer 200 of the group closest to the hole bottom and away from the dynamic sealing device 300.

[0043] In application, the coal mine directional perforation and fracturing tool string is connected to a drill pipe and pushed to a designated position in a borehole, directional perforation and fracturing are sequentially or simultaneously realized by pumping high-pressure water, the second packer 600 of each group expands to block the rear borehole of the corresponding fracturing zone, and the first packer 200 expands to block the front borehole of the corresponding fracturing zone; the directional perforator 500 of each group is driven by high-pressure water to realize directional adjustment, so that the fracturing sliding sleeve nozzle 11 is directed to a set direction; after the water pressure is increased, the valve ball 12 of each group is knocked open, high-pressure water flows out of the fracturing sliding sleeve nozzle 11 to form a high-pressure beam, and multi-stage perforation and fracturing are realized.

[0044] The extended application realizes fixed-distance multi-stage construction by connecting multiple groups of devices, and improves overall efficiency.

[0045] Finally, it should be pointed out that the above embodiments are only used to illustrate the technical solutions of the present application and are not limiting, although the present application has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that the technical solutions of the present application can be modified or replaced by equivalents without departing from the purpose and scope of the technical solutions, and all should be covered in the scope of the claims of the present application.

Claims

1. An integrated directional perforation fracturing device for coal mines, characterized in that, It includes a first packer, a dynamic sealing device, a one-way fracturing sleeve, a directional perforator, and a second packer, which are connected and communicated sequentially from one end to the other. The unidirectional fracturing sleeve includes a fracturing sleeve valve body, which has a water inlet channel and a fracturing water flow channel. The two ends of the water inlet channel are respectively connected to the dynamic sealing device and the directional perforator. One end of the fracturing water flow channel is sealed, and the other end is connected to the directional perforator. Several fracturing sleeve nozzles are radially opened on the fracturing water flow channel. The directional perforator includes an inner tube, an outer tube rotatably sleeved on the inner tube, and a drive tube slidably arranged inside the outer tube. One end of the drive tube is sleeved on the inner tube and abuts against a directional perforator spring sleeved on the inner tube to provide an elastic restoring force to the drive tube. The drive tube is provided with a tapered pressure-bearing water inlet at one end away from the inner tube of the directional perforator, so that the drive tube can move axially under the action of high pressure fluid to compress the directional perforator spring; The outer side of the inner tube of the directional perforator is provided with an annular directional track. The end of the annular directional track away from the drive tube has an axial groove, and a rolling directional ball is provided on the annular directional track. The end of the drive tube near the inner tube of the directional perforator is provided with an annular cutting tooth groove that matches the directional ball, so that when the drive tube moves, it drives the directional ball to move on the annular directional track into the axial groove, thereby driving the inner tube of the directional perforator and the unidirectional fracturing sleeve to rotate, realizing the integration of directional perforation and fracturing.

2. The integrated directional perforation fracturing device for coal mines according to claim 1, characterized in that, The dynamic sealing device includes a first dynamic sealing joint, a dynamic sealing body, and a second dynamic sealing joint connected sequentially from one end to the other, so as to ensure that the first packer does not rotate with the rotation of the unidirectional fracturing sleeve.

3. The integrated directional perforation fracturing device for coal mines according to claim 2, characterized in that, A first rigid seal and a second rigid seal are respectively provided at the connection between the first dynamic sealing joint and the second dynamic sealing joint and the dynamic sealing body.

4. The integrated directional perforation fracturing device for coal mines according to claim 1, characterized in that, The unidirectional fracturing sleeve also includes a unidirectional fracturing sleeve rear connector connected to one end of the fracturing sleeve valve body and a unidirectional fracturing sleeve front connector connected to the other end.

5. The integrated directional perforation fracturing device for coal mines according to claim 1, characterized in that, A spring seat is provided at one end of the fracturing water flow channel near the rear joint of the one-way fracturing sleeve. A fracturing sleeve spring is axially arranged on the spring seat. A valve ball is arranged at the end of the fracturing sleeve spring away from the spring seat, so as to control the opening and closing of the fracturing sleeve nozzle by the axial sliding of the valve ball.

6. The integrated directional perforation fracturing device for coal mines according to claim 1, characterized in that, The end of the drive tube away from the inner tube of the directional perforator is provided with a drive tube sealing ring that is slidably connected to the outer tube of the directional perforator.

7. The integrated directional perforation fracturing device for coal mines according to claim 1, characterized in that, A limiting ring is provided on the outside of the drive tube, and an axial limiting strip matching the limiting ring is provided on the outer tube of the directional perforator to restrict the circumferential rotation of the drive tube.

8. The integrated directional perforation fracturing device for coal mines according to claim 1, characterized in that, The outer tube and inner tube of the directional perforator are rotatably connected by bearings, and the axial displacement of the inner tube is restricted by a shoulder on the inner tube.

9. The integrated directional perforation fracturing device for coal mines according to claim 1, characterized in that, The outer tube of the directional perforator is connected to the inner cavity of the second packer to allow high-pressure water to enter the directional perforator.

10. The integrated directional perforation fracturing device for coal mines according to claim 1, characterized in that, A plug is provided at the end of the first packer away from the dynamic sealing device to seal the end of the coal mine directional perforation fracturing integrated device near the bottom of the hole.

11. The integrated coal mine directional perforation fracturing device according to any one of claims 1-9, characterized in that, The device is configured in multiple sets to form a coal mine directional perforation fracturing tool string, and a plug is used to seal one end of the coal mine directional perforation fracturing tool string near the bottom of the hole to achieve fixed-distance multi-stage fracturing construction.

12. The integrated directional perforation fracturing device for coal mines according to claim 1, characterized in that, The circular directional track is a ring-shaped guide groove. The directional ball falls into the axial groove under the push of the drive tube to keep the position of the axial groove facing a fixed design direction.

13. The integrated directional perforation fracturing device for coal mines according to claim 5, characterized in that, The valve ball cannot be opened under the first water pressure condition, and the high-pressure water flows into the first packer through the water inlet channel; Under the second water pressure condition, the valve ball is forced open, and high-pressure water enters the fracturing water flow channel to achieve perforation and fracturing. The first water pressure is less than the second water pressure.

14. A method for integrated directional perforation fracturing in coal mines, characterized in that, The integrated coal mine directional perforation fracturing device as described in any one of claims 1 to 13 includes the following steps: Connect the integrated coal mine directional perforation fracturing device to the drill rod and push it to the designated perforation position; High-pressure water is pumped in and flows sequentially into the second packer, directional perforator, one-way fracturing sleeve, dynamic sealing device and first packer; The second packer expands and seals the fracturing zone, and a hole is drilled at the rear of the fracturing zone; the first packer expands and seals the fracturing zone, and a hole is drilled at the front of the fracturing zone. High-pressure water enters the drive tube of the directional perforator, pushing the drive tube to move axially, which in turn moves the directional ball on the annular directional track to the axial groove, thereby realizing the rotation of the inner tube of the directional perforator and the one-way fracturing sleeve, so that the fracturing sleeve nozzle faces the set direction, and the high-pressure water enters the first packer through the water inlet channel; Increase the water pressure, and high-pressure water enters the fracturing water flow channel, flows out from the fracturing sliding sleeve nozzle to form a high-pressure jet, perforates the coal seam, and continues to increase the pressure after perforation to achieve fracturing.

15. The integrated method for directional perforation fracturing in coal mines according to claim 14, characterized in that, A spring seat is provided at one end of the fracturing water flow channel near the rear joint of the one-way fracturing sleeve. A fracturing sleeve spring is axially arranged on the spring seat. A valve ball is arranged at the end of the fracturing sleeve spring away from the spring seat, so as to control the opening and closing of the fracturing sleeve nozzle by the axial sliding of the valve ball. After the water pressure is increased, the high-pressure water forces open the valve ball and enters the fracturing water flow channel.

16. The integrated method for directional perforation fracturing in coal mines according to claim 14, characterized in that, Before sending the integrated coal mine directional perforation fracturing device into the borehole, adjust the angle between the fracturing sleeve nozzle in the unidirectional fracturing sleeve and the axial groove to achieve directional perforation.

17. The integrated method for directional perforation fracturing in coal mines according to claim 14, characterized in that, The method isolates the rotation of the first packer from the unidirectional fracturing sleeve through the dynamic sealing device, ensuring a stable sealing process.

18. The integrated method for directional perforation fracturing in coal mines according to claim 14, characterized in that, The method connects multiple sets of the integrated coal mine directional perforation fracturing device to the drill pipe to achieve fixed-distance multi-segment construction, which can be extended to multi-segment fracturing.

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