Single-channel multi-stage directional ejector, fracturing device and fracturing method

Abstract

The present invention provides a single-channel multi-stage controlled directional injector, comprising a tube body and a plurality of nozzles. The tube body is provided with a first through hole along its axial direction, and each nozzle is arranged on the side wall of the tube body along the axial direction of the tube body, and the nozzle is communicated with the first through hole. The present invention also comprises a plurality of sliding sleeves, a first elastic member, a first clamping platform and a plurality of blocking balls. Each sliding sleeve is adjacently and abuttedly arranged in the first through hole, and the outer wall of each sliding sleeve is in contact with the inner wall of the tube body. The inner diameter of each sliding sleeve gradually decreases along the axial direction of the tube body. Each nozzle is arranged on the side wall of the tube body at equal intervals and is respectively located at the position corresponding to each sliding sleeve and the tube body; the first clamping platform is arranged at one end of the tube body where the inner diameter of the sliding sleeve is reduced, the first elastic member is arranged in the tube body, one end is connected to the sliding sleeve in abutment, and the other end is connected to the first clamping platform, the maximum elastic deformation of the first elastic member is greater than the axial length of the sliding sleeve and less than the axial length between the two nozzles; the number of blocking balls is configured in a one-to-one correspondence with the sliding sleeve, and each blocking ball can be correspondingly clamped in the sliding sleeve.

Description

Technical Field

[0001] The invention belongs to the field of coal mining, and in particular relates to a single-channel multi-stage directional control injector, a fracturing device and a fracturing method. Background Art

[0002] In coal mining, mine gas disasters have always been one of the main disasters threatening coal mine safety production. At present, the most common and effective technical means for mine gas control is coal seam gas extraction, which extracts the gas in the coal seam in advance and reduces the gas content in the coal seam to meet the safe and efficient mining of coal mines. Most of the coal seams in my country are broken and soft, with low permeability. It is difficult to drill holes in this coal seam. The top (bottom) plate of the coal seam is easy to drill holes, but the direction of fracturing cracks is difficult to control. The directional perforating device is an important means to ensure that the cracks start to crack in the coal seam. Directional fracturing is an important means and development direction for coal seam gas control in the future. A small part of the existing technology uses perforating bullet perforation technology, but the technology has a high instantaneous construction pressure, which causes great damage to the production casing, and also has a compaction effect on the reservoir, which has a great adverse effect. In addition, the segmented hydraulic fracturing used in the prior art is a method of using a high-pressure pump group to inject high-pressure fluid into the confined space in the coal rock hole formed by the sealing tool through the in-hole pipe string for a short time, so that the coal rock breaks and produces a crack network, forming a gas channel or weakening the strength of the coal rock. It is a new technology in the field of prevention and control of underground gas permeability, coal rock weakening, and strong mine pressure in coal mines. Therefore, forming prefabricated cracks by spraying in the fracturing section range and then performing segmented fracturing is the main measure to control the scale of fracturing cracks and improve the fracturing effect at this stage. The existing coal mine underground jet fracturing process is: a single-channel multi-stage controlled directional injector is sent into the hole through a pipe string, and the injection is carried out at the designed position. After completion, a single-channel multi-stage controlled directional injector is withdrawn, and then the fracturing tool is sent through the pipe string for segmented hydraulic fracturing construction. The disadvantages of this method include: cumbersome construction procedures, low injection position accuracy, unclear injection direction, and uncontrollable injection scale. Summary of the invention

[0003] In view of the deficiencies in the prior art, the purpose of the present invention is to provide a single-channel multi-stage directional injector, a fracturing device and a fracturing method to solve the problems in the prior art.

[0004] In order to solve the above technical problems, the present invention adopts the following technical solutions to achieve the above problems:

[0005] A single-channel multi-stage directional control injector comprises a tube body and a plurality of nozzles, wherein the tube body is provided with a first through hole along its axial direction, each nozzle is provided on the side wall of the tube body along the axial direction of the tube body, and the nozzle is communicated with the first through hole, and further comprises a plurality of sliding sleeves, a first elastic member, a first clamping platform and a plurality of blocking balls;

[0006] The sliding sleeves are adjacently disposed in the first through hole, the outer wall of each sliding sleeve is in contact with the inner wall of the tube body, the inner diameter of each sliding sleeve gradually decreases along the axial direction of the tube body, and the nozzles are evenly spaced on the side wall of the tube body and are respectively located at positions corresponding to each sliding sleeve and the tube body;

[0007] The first clamping platform is arranged at one end of the tube body sliding sleeve where the inner diameter is reduced, the first elastic member is arranged in the tube body, one end of the first elastic member is in contact with the sliding sleeve, and the other end is connected to the first clamping platform, and the maximum elastic deformation of the first elastic member is greater than the axial length of the sliding sleeve and less than the axial length between the two nozzles;

[0008] The number of the blocking balls is configured in one-to-one correspondence with the sliding sleeve, and each blocking ball can be correspondingly clamped in the sliding sleeve.

[0009] Preferably, the single-channel multi-stage directional control injector further comprises:

[0010] The second mounting platform is arranged at one end of the tube body away from the first clamping platform, the second mounting platform is provided with a second through hole along its axial direction, and the second mounting platform is in abutting connection with the sliding sleeve.

[0011] Preferably, each adjacent sliding sleeve is connected via a second elastic member.

[0012] Preferably, a plurality of nozzles are arranged on the side wall of the tube body corresponding to each sliding sleeve along the circumference thereof.

[0013] Preferably, each of the sliding sleeves and the tube body is arranged to be non-rotatable relative to each other.

[0014] Preferably, a slide groove is provided on the tube body, and a protrusion is provided at a position corresponding to the slide sleeve, and the protrusion matches the slide groove.

[0015] Preferably, the central axes of the tube body, the sliding sleeve, the first elastic member, the first clamping platform and the second mounting platform are arranged colinearly.

[0016] A fracturing device comprises a single-channel multi-stage directional control injector, and also comprises a packer, a constant pressure cutoff device, a fracturing pipe string and a guide shoe which are connected in sequence; the single-channel multi-stage directional control injector is connected to the packer and the constant pressure cutoff device respectively.

[0017] A fracturing method, wherein the method relies on a fracturing device to complete the operation;

[0018] The specific steps include:

[0019] Step 1: Determine the hydraulic fracturing layer and the scale of fracturing impact according to the type of treatment problem, and determine the injection channel that needs to be opened to perform directional drilling construction to form a fracturing borehole according to the scope of fracturing impact;

[0020] Step 2, sending the fracturing device to the designed position of the fracturing drilling hole, and accurately delivering it to the designed position through the guide shoe;

[0021] Step 3: Select the corresponding plugging ball as needed, and push it into the matching sliding sleeve under the action of fracturing fluid and injection fluid. The sliding sleeve at this position moves downstream, so that the nozzle is connected to the first through hole, and the nozzle is opened to release the injection fluid;

[0022] Step 4: After the injection is completed, the supply of fracturing fluid and injection fluid is stopped, the first elastic member returns to a free state to bounce the high-density ball back, and the high-density ball is recovered. After the first stage of construction is completed, the equipment is dragged to the next injection fracturing section position, and the next stage of fracturing construction is started, and the cycle is repeated in sequence until the designed fracturing is completed.

[0023] Compared with the prior art, the present invention has the following technical effects:

[0024] (I) The present invention allows the injection fluid and the fracturing fluid to run in the same loop under the single-channel operation of the first through hole in the pipe body, thereby realizing the integrated operation of injection-fracturing. At the same time, a plurality of sliding sleeves with decreasing inner diameters are arranged in the pipe body, and different plugging balls that can be stuck in the sliding sleeves are matched according to the inner diameters of each sliding sleeve. Under the action of the plugging balls and the sliding sleeves, the injection fluid and the fracturing fluid are injected through the first through hole, and the sliding sleeve where the plugging ball is located is pushed by the injection fluid and the fracturing fluid to move in the pipe body, and the nozzle arranged on the side wall of the pipe body corresponding to the sliding sleeve is connected to the first channel, and the fracturing fluid is discharged from the nozzle. The first clamping platform is arranged at the bottom of the hydraulic fracturing plate, and the first elastic member is abutted against the first elastic member to limit the elastic range of the first elastic member. When the fracturing injection is completed, the injection liquid and the fracturing fluid are released. When the first elastic member recovers to a free state, the elastic potential energy is released to provide power to push the sleeve to its original position, thereby achieving the self-resetting purpose of the sleeve and facilitating the next cycle of work. The present invention achieves the purpose of precise management; in actual operation, it can greatly reduce the construction period, improve construction accuracy, facilitate operation, and reduce labor and equipment costs; it has high practical value and promotion value. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 is a cross-sectional view of a single-channel multi-stage directional control injector of the present invention;

[0026] Figure 2 It is a schematic diagram of the working state of the single-channel multi-stage directional control injector of the present invention;

[0027] Figure 3 It is a schematic diagram of the working state of the single-channel multi-stage directional control injector of the present invention;

[0028] Figure 4 is a stereoscopic diagram of a single-channel multi-stage directional control injector of the present invention;

[0029] Figure 5 It is a schematic diagram of the overall structure of the fracturing device of the present invention;

[0030] Figure 6 It is a schematic diagram of the fracturing working state of the fracturing device of the present invention;

[0031] Figure 7 It is a schematic diagram of the fracturing working state of the fracturing device of the present invention;

[0032] Figure 8 is a cross-sectional view of a fracturing device of the present invention;

[0033] Fig. 9 Schematic diagram of multi-directional injection of a single-channel multi-stage directional injector of the present invention;

[0034] Fig.10 1 is a schematic diagram of a one-way injection of a single-channel multi-stage directional injection device of the present invention;

[0035] Fig.11 is a schematic diagram of the hydraulic fracturing of a comparative example of the present invention;

[0036] Fig.12 It is a schematic diagram of the lateral suspended ceiling area of ​​Example 3 of the present invention;

[0037] Fig.13 It is a schematic diagram of the influence range of the hydraulic fracturing ellipsoid of Example 3 of the present invention;

[0038] Fig.14 is a schematic diagram of the position of the artificial fault line of Example 3 of the present invention;

[0039] Fig.15 is a schematic structural diagram of an ejector according to Embodiment 3 of the present invention;

[0040] Fig.16 is a schematic diagram of the plan layout of the fracturing drilling holes in Example 3 of the present invention;

[0041] Fig.17 is a schematic diagram of the formation process of an artificial fault line in Example 3 of the present invention;

[0042] The meaning of each number in the figure is:

[0043] 100-tube body, 110-nozzle, 3-first through hole, 200-sleeve, 400-first elastic member, 700-first clamping platform, 600-second mounting platform, 9-second through hole, 1000-packer, 1200-constant pressure interceptor, 1100-fracturing string, 900-guide shoe, 800-single-channel multi-stage directional control injector.

[0044] The specific contents of the present invention are further explained in detail below in conjunction with embodiments. DETAILED DESCRIPTION

[0045] Specific embodiments of the present invention are given below. It should be noted that the present invention is not limited to the following specific embodiments, and all equivalent changes made on the basis of the technical solution of this application fall within the protection scope of the present invention.

[0046] The directional terms mentioned in this article, such as "circumferential", "radial", "axial", "upstream" and "downstream", are consistent with the specific directions on the paper of the drawings in the specification or the corresponding directions in the space shown in the drawings.

[0047] Embodiment 1:

[0048] A single-channel multi-stage directional control injector includes a tube body 100 and a plurality of nozzles 110. The tube body 100 is provided with a first through hole along its axial direction. Each nozzle 110 is provided on the side wall of the tube body 100 along the axial direction of the tube body 100, and the nozzle 110 is communicated with the first through hole. The single-channel multi-stage directional control injector includes a plurality of sliding sleeves 200, a first elastic member 400, a first clamping platform 700 and a plurality of blocking balls 300.

[0049] Each of the sliding sleeves 200 is disposed adjacently and abuttingly in the first through hole, the outer wall of each sliding sleeve 200 contacts the inner wall of the tube body 100, the inner diameter of each sliding sleeve 200 gradually decreases along the axial direction of the tube body 100, and each of the nozzles 110 is disposed on the side wall of the tube body 100 at equal intervals and is respectively located at the corresponding position of each sliding sleeve 200 and the tube body 100;

[0050] The first clamping platform 700 is arranged at the end of the tube body 100 where the inner diameter of the sleeve is reduced. The first elastic member 400 is arranged in the tube body 100, one end of which is in contact with the sleeve 200 and the other end of which is connected to the first clamping platform 700. The maximum elastic deformation of the first elastic member 400 is greater than the axial length of the sleeve and less than the axial length between the two nozzles.

[0051] The number of the blocking balls 300 is configured in a one-to-one correspondence with the sliding sleeve 200, and each blocking ball 300 can be correspondingly mounted in the sliding sleeve.

[0052] In this embodiment, the injection liquid and the fracturing fluid are operated in the same circuit under the single-channel operation of the first through hole in the pipe body, so as to realize the integrated operation of injection-fracturing. At the same time, a plurality of sliding sleeves with decreasing inner diameters are arranged in the pipe body, and different plugging balls that can be stuck in the sliding sleeves are matched according to the inner diameters of the sliding sleeves. Under the action of the plugging balls and the sliding sleeves, the injection liquid and the fracturing fluid are injected through the first through hole, and the sliding sleeve where the plugging ball is located is pushed by the injection liquid and the fracturing fluid to move in the pipe body, and the nozzle arranged on the side wall of the pipe body corresponding to the sliding sleeve is connected with the first channel, and the fracturing fluid is discharged from the nozzle. The first elastic member is arranged on the first clamping platform to abut against the first elastic member to limit the elastic range of the first elastic member. When the fracturing injection is completed, the injection liquid and the fracturing fluid are released. When the first elastic member recovers to a free state, the elastic potential energy is released to provide power to push the sleeve to its original position, thereby achieving the self-resetting purpose of the sleeve and facilitating the next cycle of work. The present invention achieves the purpose of precise management; in actual operation, it can greatly reduce the construction period, improve construction accuracy, facilitate operation, and reduce labor and equipment costs; it has high practical value and promotion value.

[0053] Among them, the purpose of setting the maximum elastic deformation of the first elastic member 400 greater than the axial length of the sleeve and less than the axial length between the two nozzles is to enable the axial displacement of the sleeve to expose the nozzle at the corresponding position, to ensure that the nozzle is connected to the first through hole, and to ensure that only one nozzle at the corresponding position is opened when the sleeve moves, without opening the nozzle of the next level, thereby achieving precise control, and the sealing ball adopts a high-density spherical structure.

[0054] As a preferred solution of this embodiment, the single-channel multi-stage directional control injector further includes:

[0055] The second mounting platform 600 is disposed at one end of the tube body 100 away from the first clamping platform 700 . The second mounting platform 600 is provided with a second through hole along its axial direction. The second mounting platform 600 is in contact connection with the sliding sleeve 200 .

[0056] The second mounting platform 600 can prevent the sliding sleeve from being overstressed and extending out of the tube body when the first elastic member releases elastic potential energy to push the sliding sleeve to reset, thereby improving the accuracy of the sliding sleeve reset.

[0057] As a preferred solution of this embodiment, adjacent sliding sleeves 200 are connected via a second elastic member 500 .

[0058] Among them, the two adjacent sliding sleeves can maintain a stable connection under the action of the second elastic member to prevent the sliding sleeve upstream of the corresponding nozzle from sliding. After the injection liquid is released, the two adjacent sliding sleeves separated from each other can also automatically offset each other under the elastic force of the second elastic member. In this embodiment, the second elastic member is selected from a spring or spring sheet structure, and the connection position of the second elastic member is preferably to avoid the corresponding nozzle position.

[0059] As a preferred solution of this embodiment, a plurality of nozzles are arranged on the side wall of the tube body 100 corresponding to each sliding sleeve 200 along the circumference thereof.

[0060] Among them, multiple nozzles are arranged along the axial direction of the pipe body 100 to realize multi-directional injection working conditions. The purpose is: according to the actual working conditions, directional injection fracturing construction can be carried out to prefabricate cracks and achieve hydraulic fracturing construction effects with controllable crack direction and controllable weakening scale.

[0061] As a preferred solution of this embodiment, the sliding sleeves 200 and the tube body 100 are arranged to be non-rotatable relative to each other, which can enhance the stability of the injector and improve the injection efficiency.

[0062] As a preferred solution of this embodiment, a slide groove is arranged on the tube body (100), and a protrusion is arranged at a position corresponding to the slide sleeve (200), and the protrusion matches the slide groove to meet the purpose of preventing the slide groove and the tube body (100) from being relatively rotated during construction. The arrangement of the slide groove and the protrusion does not affect the operation of the nozzle.

[0063] As a preferred solution of this embodiment, the central axes of the tube body 100, the sleeve 200, the first elastic member 400, the first clamping platform 700 and the second mounting platform 600 are arranged colinearly to improve the overall stability of the device and further improve the working efficiency of this embodiment.

[0064] Embodiment 2:

[0065] A fracturing device includes the single-channel multi-stage directional control injector of Example 1, and also includes a packer 1000, a constant pressure cutoff device 1200, a fracturing pipe string 1100 and a guide shoe 900 connected in sequence; the single-channel multi-stage directional control injector 800 is connected to the packer 1000 and the constant pressure cutoff device 1200 respectively.

[0066] The fracturing device of this embodiment can adopt single-channel operation so that the injection liquid and the fracturing fluid run in the same circuit, realizing the integrated operation of injection-fracturing, wherein the injection angle control component arranged in the injector tube body of the single-channel multi-stage controlled injector can control the corresponding nozzle to open, thereby releasing the injection liquid to realize accurate fracturing construction; that is, by inserting high-density balls of different diameters into the corresponding sliding sleeve, the sliding sleeve can move to one side of the tube body under the action of the injection liquid after being blocked by the high-density balls, so that the corresponding nozzle is opened; after the injection liquid is released, the sliding sleeve is automatically reset under the elastic force of the reset elastic member; the purpose of controlling the injection direction and scale by inserting is achieved, thereby controlling the development direction and range of the fracturing cracks, effectively controlling the scale of the fracturing cracks and improving the fracturing effect, and accurately controlling the injection of the injection liquid; in actual operation, the construction period can be greatly reduced, the construction accuracy can be improved, the operation is convenient, and the labor and equipment costs can be reduced.

[0067] Embodiment 3:

[0068] A fracturing method, using a fracturing device of Example 3 to complete the operation, specifically comprising the following steps:

[0069] Step 1: Determine the hydraulic fracturing layer and the scale of fracturing impact according to the type of treatment problem, and determine the injection channel that needs to be opened to perform directional drilling construction to form a fracturing borehole according to the scope of fracturing impact;

[0070] During the mining process of working face a in a certain mine, the coal seam is buried deep, and there is a hard rock layer with a thickness of h on the roof of the coal seam, which is difficult to fall as it is mined, and is prone to stress concentration. When the mining of the adjacent working face b is completed, the hard roof forms a certain hanging roof on the side of the coal pillar of the mining roadway of working face a, resulting in serious deformation of roadway i of working face a, high maintenance cost, and serious impact on safe production continuity.

[0071] The rock fracture angle is calculated through parameters such as rock internal friction coefficient and internal friction angle.

[0072] Using the theoretical calculation formula:

[0073]

[0074] Where α is the rock fracture angle, is called the internal friction angle of the rock. μ is the internal friction coefficient.

[0075] Based on the parameters of the in-situ stress parameters in the study area, the coal seam burial depth H, the physical and mechanical parameters of the coal and rock strata (including bulk density, thickness, burial depth, internal friction angle, cohesion, bulk modulus), working face length, etc., FLAC 3d The simulation software was used to establish the Mohr-Coulomb model and conduct numerical simulation analysis of hydraulic fracturing to obtain the hydraulic fracturing parameters under this condition, including water injection volume, fracturing time, etc. The simulation showed that during the hydraulic fracturing of the hard roof, the main cracks developed in the horizontal direction, forming an ellipsoidal influence range, with the major axis radius of the ellipsoid being x1 and the minor axis radius being x2.

[0076] In order to ensure the effective collapse of the lateral suspended roof, it is necessary to prefabricate an artificial fracture line, and the location of the artificial fracture line is on the side of the i coal pillar of the roadway.

[0077] The ejector openings are m1, m2, ... m n Combined with the hard roof breaking angle α, determine the channel that needs to be opened for directional injection (the channel with the angle with the vertical line closest to the roof breaking angle) m x .

[0078] Determination of fracturing drilling parameters: including the length of the drilling hole L, the horizontal distance from the coal pillar L1 and the vertical distance from the coal seam roof L2. The fracturing drilling hole is arranged in the middle of the hard roof in the vertical direction. According to the parameters such as the hard roof fracture angle α and the hard rock layer thickness h, the fracturing drilling hole is arranged in the middle of the hard rock layer. The position of the fracturing drilling hole is determined by combining trigonometric calculations. The length of the fracturing drilling hole L is determined according to the scope of treatment.

[0079] Step 2: The spacing between adjacent fracturing sections is s=2x2. The first fracturing section is designed to be the bottom of the borehole, and the guide shoe is accurately delivered to the first fracturing position.

[0080] Step 3: When operating, a corresponding plugging ball is selected as needed and pushed into a matching sliding sleeve under the action of the fracturing fluid and the injection fluid. The sliding sleeve at this position moves downstream, so that the nozzle is connected to the first through hole, and the nozzle is opened to release the injection fluid;

[0081] Step 4: After the injection is completed, the supply of fracturing fluid and injection fluid is stopped, the first elastic member returns to a free state to bounce the high-density ball back, and the high-density ball is recovered. After the first stage of construction is completed, the equipment is dragged to the next injection fracturing section position, and the next stage of fracturing construction is started, and the cycle is repeated in sequence until the designed fracturing is completed.

[0082] Comparative Example:

[0083] The fracturing fluid is sprayed in a non-directional manner at the same pressure as in Example 3. Fig.11 As shown, the expansion range and extension direction of the fracturing cracks are uncontrollable, and the weakening effect is not ideal. Especially under the working conditions requiring directional fracturing, the fracturing effect is difficult to control.

Claims

1. A single-channel multi-stage directional injector, comprising a tube body (100) and a plurality of nozzles (110), wherein the tube body (100) is provided with a first through hole along its axial direction, each nozzle (110) is provided on a side wall of the tube body (100) along the axial direction of the tube body (100), and the nozzle (110) is communicated with the first through hole, characterized in that: It also includes a plurality of sliding sleeves (200), a first elastic member (400), a first clamping platform (700) and a plurality of blocking balls (300); The sliding sleeves (200) are adjacently abutted and arranged in the first through hole, the outer wall of each sliding sleeve (200) contacts the inner wall of the tube body (100), the inner diameter of each sliding sleeve (200) gradually decreases along the axial direction of the tube body (100), and the nozzles (110) are arranged on the side wall of the tube body (100) at equal intervals and are respectively located at positions corresponding to each sliding sleeve (200) and the tube body (100); The first clamping platform (700) is arranged at an end of the tube body (100) where the inner diameter of the sliding sleeve is reduced, the first elastic member (400) is arranged in the tube body (100), one end of the first elastic member (400) is in contact with the sliding sleeve (200), and the other end is connected to the first clamping platform (700), and the maximum elastic deformation of the first elastic member (400) is greater than the axial length of the sliding sleeve and less than the axial length between the two nozzles; The number of the blocking balls (300) is configured in one-to-one correspondence with the sliding sleeve (200), and each blocking ball (300) can be correspondingly mounted in the sliding sleeve; The single-channel multi-stage directional control injector further comprises: a second mounting platform (600), the second mounting platform (600) being arranged at one end of the tube body (100) away from the first clamping platform (700), the second mounting platform (600) being provided with a second through hole along its axial direction, and the second mounting platform (600) being in contact connection with the sliding sleeve (200).

2. The single-channel multi-stage directional injector according to claim 1, characterized in that: Each adjacent sliding sleeve (200) is connected via a second elastic member (500).

3. The single-channel multi-stage directional injector according to claim 1, characterized in that: A plurality of nozzles are arranged on the side wall of the tube body (100) corresponding to each sliding sleeve (200) along its circumference.

4. The single-channel multi-stage directional injector according to claim 1, characterized in that: Each of the sliding sleeves (200) and the tube body (100) is arranged to be non-rotatable relative to each other.

5. The single-channel multi-stage directional injector according to claim 4, characterized in that: A sliding groove is arranged on the tube body (100), and a protrusion is arranged on the sliding sleeve (200) at a position corresponding to the sliding groove, and the protrusion matches the sliding groove.

6. The single-channel multi-stage directional injector according to claim 1, characterized in that: The central axes of the tube body (100), the sliding sleeve (200), the first elastic member (400), the first clamping platform (700) and the second mounting platform (600) are arranged colinearly.

7. A fracturing device, comprising the single-channel multi-stage directional control injector according to any one of claims 1 to 6, and also comprising a packer (1000), a constant pressure cutoff device (1200), a fracturing pipe string (1100) and a guide shoe (900) connected in sequence; the single-channel multi-stage directional control injector (800) is connected to the packer (1000) and the constant pressure cutoff device (1200), respectively.

8. A fracturing method, characterized in that: The method is performed by relying on the fracturing device described in claim 7; The specific steps include: Step 1: Determine the hydraulic fracturing layer and the scale of fracturing impact according to the type of treatment problem, and determine the injection channel that needs to be opened to perform directional drilling construction to form a fracturing borehole according to the scope of fracturing impact; Step 2, sending the fracturing device to the designed position of the fracturing drilling hole, and accurately delivering it to the designed position through the guide shoe; Step 3: Select the corresponding plugging ball as needed, and push it into the matching sliding sleeve under the action of fracturing fluid and injection fluid. The sliding sleeve at this position moves downstream, so that the nozzle is connected to the first through hole, and the nozzle is opened to release the injection fluid; Step 4: After the injection is completed, the supply of fracturing fluid and injection fluid is stopped, the first elastic member returns to a free state to bounce the high-density ball back, and the high-density ball is recovered. After the first stage of construction is completed, the equipment is dragged to the next injection fracturing section position, and the next stage of fracturing construction is started, and the cycle is repeated in sequence until the designed fracturing is completed.

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