Shale gas reservoir gas injection pressure channeling interference prevention device and method

Abstract

The invention relates to the technical field of shale oil and gas development, and provides a shale gas reservoir gas injection pressure channeling interference prevention device and method.The shale gas reservoir gas injection pressure channeling interference prevention device comprises a shaft annulus, a main oil pipe located in the shaft annulus and a packer arranged between the shaft annulus and a main oil pipe interlayer; the rotating sleeve is arranged outside the framework in a sleeving manner and can rotate outside the framework; the driving device is used for driving the rotating sleeve to rotate relative to the framework; the pneumatic assembly can be driven by the rotating sleeve to transversely move in the length direction of the framework; the rotary sleeve is driven by the driving device to rotate relative to the framework, the positioning assembly is driven by rotation of the rotary sleeve to abut against the inner pipe wall of the shaft annulus and the outer pipe wall of the main oil pipe, the positioning action of the packer is achieved, and compared with the prior art, the packer has the good positioning effect, and the positioning effect is good. And displacement is prevented from occurring in the gas injection and pressurization process to affect the operation of gas injection and pressurization in the well.

Description

Technical Field

[0001] The present invention relates to the technical field of shale oil and gas development, and in particular to a shale gas reservoir gas injection pressure channeling prevention interference device and method. Background Art

[0002] Gas injection to prevent pressure channeling in shale gas reservoirs is a method designed specifically to address the pressure channeling and well-to-well interference problems that occur during shale gas production. The main purpose of this technology is to reduce the pressure difference between the two corresponding wells (such as a new fracturing well and an old production well) by injecting high-pressure gas (such as CO2) into the production well, thereby preventing well-to-well channeling interference. This method can significantly increase the gas production rate of shale gas wells, reduce the ineffective use of fracturing fluid in fracturing wells, and effectively improve the economic benefits of shale gas reservoir production.

[0003] For example, the patent technology with announcement number CN118088138A discloses a method for preventing pressure interference during gas injection in shale gas reservoirs, which includes the following steps: connecting a gas injection and boosting system that is tightly connected to the wellbore annulus to the target shale gas well; closing the oil production and gas injection channels to stop production; obtaining the gas injection volume based on the formation pressure and pore volume parameters in the logging and well data; injecting carbon dioxide gas into the target formation according to the obtained gas injection volume based on the gas injection and boosting system; after the gas injection and boosting are completed, opening the gas production valve of the target shale gas well to implement production. This technical solution reduces the pressure difference between the corresponding two wells without controlling the scale of fracturing fluid use by injecting high-pressure gas into the production well, effectively preventing the occurrence of cross-flow interference between wells.

[0004] The above-mentioned shale gas reservoir gas injection pressure interference prevention technology requires placing a packer at the starting position of the first stage of fracturing in the target formation before using the gas injection and pressurization system to inject gas into the shale gas well, so as to prevent the gas from entering the oil pipe through the annulus during the later gas injection and pressurization process, thereby causing ineffective gas injection and pressurization.

[0005] Most existing packers are one-piece structures made of rubber material, such as a packer structure disclosed in the patent technology with announcement number CN114075940B, which includes a packer body, on which a sealing ring and a stop ring are provided; a packer rubber cylinder assembly provided on the packer body, and the packer rubber cylinder assembly is provided between the sealing ring and the stop ring; wherein the stop ring is fixedly connected to the packer body, and the sealing ring slides on the packer body under the action of the sealing force, and pushes the packer rubber cylinder assembly to deform, thereby completing the sealing. Although the packer structure is simple in structure, low in manufacturing cost and good in sealing, it has poor mobility. Due to the complex environment in the well and the change in air pressure, there is a certain deformation in the pipe, which makes it difficult for the one-piece packer to move in the well.

[0006] In addition, the existing packers also have expansion structures, such as an expansion packer assembly and a packer disclosed in the patent technology with announcement number CN107829705B. The packer assembly includes an expansion tube, which includes a frame, an inner layer and an outer layer. The inner layer is arranged on the inner side of the frame, and the outer layer is arranged on the outer side of the frame. The frame is made of metal, and a rubber protective tube is also arranged outside the expansion tube, which can reduce the jamming caused by the deformation and expansion of the expansion tube during the process of the packer going down the well, making it easier to go down the well and improving the reliability of the packer. Although the packer structure can achieve expansion to facilitate the movement of the packer in the well, the structural design is difficult to ensure the sealing of the wellbore annulus and the main oil pipe double pipe. Summary of the invention

[0007] The present invention provides a shale gas reservoir gas injection pressure channeling prevention interference device and method, which solves the problems of packer travel and the sealing of wellbore annulus and main oil pipe double pipe in the prior art.

[0008] The technical solution of the present invention is as follows: a shale gas reservoir gas injection pressure channeling interference prevention device, comprising a wellbore annulus, a main oil pipe located in the wellbore annulus, and a packer placed between the wellbore annulus and the main oil pipe interlayer, the packer comprising:

[0009] A skeleton, which is sleeved on the outside of the main oil pipe;

[0010] A rotating sleeve, which is sleeved outside the frame and can rotate outside the frame;

[0011] A driving device, used for driving the rotating sleeve to rotate relative to the frame;

[0012] A pneumatic assembly capable of moving laterally along the length direction of the frame under the drive of the rotating sleeve;

[0013] The positioning assembly is synchronously driven by the rotating sleeve to contact the inner wall of the wellbore annulus and the outer wall of the main oil pipe;

[0014] A return spring, used to elastically connect the pneumatic assembly to the frame;

[0015] A first elastic membrane expands under the action of the pneumatic assembly and comes into sealing contact with the inner pipe wall of the wellbore annulus;

[0016] The second elastic membrane expands under the action of the pneumatic component and comes into sealing contact with the outer wall of the main oil pipe.

[0017] Preferably, the skeleton includes an outer sleeve and an inner sleeve sleeved in the outer sleeve, a first fixing plate is fixed to one end of the outer sleeve, a second fixing plate is fixed to the other end of the outer sleeve, a sealing cover is fixed to the end of the inner sleeve facing the first fixing plate, two ends of the first elastic membrane are respectively fixed to the first fixing plate and the sealing cover, two ends of the second elastic membrane are respectively fixed to the second fixing plate and the inner sleeve, strip limiting grooves are provided at the top and bottom of the outer sleeve, and a plurality of arc limiting grooves distributed in an annular manner are provided on the second fixing plate.

[0018] Preferably, the first fixing plate, the sealing cover and the first elastic membrane enclose a first chamber, and the sealing cover is provided with a first through hole communicating with the first chamber.

[0019] Preferably, the first fixing plate, the second fixing plate, the outer sleeve and the inner sleeve together form a second chamber, and the first fixing plate is provided with a second through hole communicating with the second chamber.

[0020] Preferably, two ends of the rotating sleeve are rotatably connected to the first fixed disk and the second fixed disk respectively, an arc-shaped tooth segment is fixed on the outer surface of the rotating sleeve, and two spiral limiting grooves corresponding to the strip limiting grooves are provided on the rotating sleeve.

[0021] Preferably, the driving device comprises a motor, the motor is fixed on the second fixed disk, and a gear meshing with the arc-shaped tooth segment is fixed to the output end of the motor.

[0022] Preferably, the pneumatic component includes a slip ring, one end of the slip ring is provided with a sliding plate that slides through the first fixed plate, the outer end of the sliding plate is fixed with a first pressing plug that is slidably limited in the first chamber, the other end of the slip ring is fixed with a second pressing plug that is slidably limited in the second chamber, and the top and bottom of the slip ring are fixed with fixing rods, and the two fixing rods respectively penetrate two strip limiting grooves and are limited in two spiral limiting grooves.

[0023] Preferably, one end of the return spring abuts against the second press plug, and the other end of the return spring abuts against the second fixed disk.

[0024] Preferably, the positioning assembly includes a first clamping block and a second clamping block, the first clamping block and the second clamping block are both rotatably arranged on the second fixed disk by a rotating shaft, the proximal ends of the first clamping block and the second clamping block are provided with mutually meshing fan-shaped teeth, the distal ends of the first clamping block and the second clamping block are fixed with anti-slip strips, the end of the rotating sleeve close to the positioning assembly is fixed with a second hinge shaft limited to the arc-shaped limiting groove, the outer end of the second hinge shaft is hinged with a connecting rod, and the end of the connecting rod away from the second hinge shaft is hinged to the first clamping block through the first hinge shaft.

[0025] Based on the above-mentioned shale gas reservoir gas injection pressure channeling interference device, the present invention also proposes a shale gas reservoir gas injection pressure channeling interference prevention method, comprising the following steps:

[0026] Step 1: placing the packer between the wellbore annulus and the interlayer of the main oil pipe;

[0027] Step 2, turning on the driving device to drive the rotating sleeve to rotate relative to the frame;

[0028] Step 3: The pneumatic assembly begins to move laterally along the length direction of the frame under the drive of the rotating sleeve to overcome the elastic force of the return spring;

[0029] Step 4: The positioning assembly is driven by the rotation of the rotating sleeve to contact the inner wall of the wellbore annulus and the outer wall of the main oil pipe to achieve the positioning action of the packer;

[0030] Step 5: The lateral movement of the pneumatic assembly causes the first elastic membrane to expand and seal against the inner wall of the wellbore annulus, and at the same time causes the second elastic membrane to expand and seal against the outer wall of the main oil pipe, thereby achieving interlayer sealing between the wellbore annulus and the main oil pipe.

[0031] The beneficial effects of the present invention are:

[0032] 1. In the present invention, the driving device drives the rotating sleeve to rotate relative to the frame, and the positioning assembly is driven by the rotation of the rotating sleeve to contact the inner pipe wall of the wellbore annulus and the outer pipe wall of the main oil pipe to achieve the positioning action of the packer. Compared with the prior art, the packer used in the present invention has a better positioning effect, which prevents displacement during the gas injection and pressurization process and affects the operation of gas injection and pressurization in the well;

[0033] 2. When the rotating sleeve in the present invention rotates relative to the frame, the pneumatic component can overcome the elastic force of the return spring and move laterally along the length direction of the frame under the drive of the rotating sleeve, which can cause the first elastic membrane to expand and seal with the inner pipe wall of the wellbore annulus, and at the same time cause the second elastic membrane to expand and seal with the outer pipe wall of the main oil pipe. Compared with the prior art, the present invention adopts an internal and external double seal method to achieve the interlayer sealing of the wellbore annulus and the main oil pipe. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] The present invention will be further described in detail below in conjunction with the accompanying drawings and specific embodiments.

[0035] Figure 1 A schematic diagram of the placement position of the packer proposed in the present invention;

[0036] Figure 2 A schematic diagram of the structure of the packer proposed in the present invention;

[0037] Figure 3 A schematic diagram of a half-section structure of a packer proposed in the present invention;

[0038] Figure 4 A schematic diagram of a half-section structure of the skeleton proposed in the present invention;

[0039] Figure 5 This is a schematic diagram of the structure of the rotating sleeve proposed by the present invention;

[0040] Figure 6 This is a schematic diagram of the structure of the pneumatic component proposed by the present invention;

[0041] Figure 7 This is a schematic diagram of the positioning component structure proposed by the present invention;

[0042] In the figure: 1, wellbore annulus; 2, main oil pipe; 3, packer; 31, skeleton; 311, outer casing; 312, first fixed plate; 313, second fixed plate; 314, inner casing; 315, cover; 316, first chamber; 317, strip limiting groove; 318, arc limiting groove; 319, second chamber; 3110, first through hole; 3111, second through hole; 32, rotating sleeve; 321, arc tooth segment; 322, spiral limiting groove; 33, driving device; 3 31. Motor; 332. Gear; 34. Pneumatic assembly; 341. Slip ring; 342. Slide; 343. First press plug; 344. Second press plug; 345. Fixing rod; 35. Positioning assembly; 351. First clamping block; 352. Second clamping block; 353. Rotating shaft; 354. Fan-shaped teeth; 355. First hinge shaft; 356. Connecting rod; 357. Second hinge shaft; 358. Anti-slip strip; 36. Return spring; 37. First elastic membrane; 38. Second elastic membrane. DETAILED DESCRIPTION

[0043] The following will be combined with 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.

[0044] See also Figure 1 , Figure 2 and Figure 3The present invention provides a technical solution: a shale gas reservoir gas injection anti-pressure channeling interference device, comprising a wellbore annulus 1, a main oil pipe 2 located in the wellbore annulus 1, and a packer 3 placed between the wellbore annulus 1 and the main oil pipe 2. The packer 3 comprises a skeleton 31, a rotating sleeve 32, a driving device 33, a pneumatic component 34, a positioning component 35, a reset spring 36, a first elastic membrane 37 and a second elastic membrane 38, wherein the skeleton 31 is sleeved on the outside of the main oil pipe 2, the rotating sleeve 32 is sleeved on the outside of the skeleton 31 and can rotate outside the skeleton 31, and the driving device 33 is used to In order to drive the rotating sleeve 32 to rotate relative to the skeleton 31, the pneumatic component 34 can move laterally along the length direction of the skeleton 31 under the drive of the rotating sleeve 32, and the positioning component 35 is in contact with the inner pipe wall of the wellbore annulus 1 and the outer pipe wall of the main oil pipe 2 under the synchronous drive of the rotating sleeve 32. The return spring 36 is used to elastically connect the pneumatic component 34 and the skeleton 31. The first elastic membrane 37 is expanded under the action of the pneumatic component 34 and is in sealing contact with the inner pipe wall of the wellbore annulus 1. The second elastic membrane 38 is expanded under the action of the pneumatic component 34 and is in sealing contact with the outer pipe wall of the main oil pipe 2.

[0045] Based on the above embodiments, the present invention further proposes a method for preventing pressure interference during gas injection in a shale gas reservoir, comprising the following steps:

[0046] Step 1: placing the packer 3 between the wellbore annulus 1 and the interlayer of the main oil pipe 2;

[0047] Step 2: Turn on the driving device 33 to drive the rotating sleeve 32 to rotate relative to the frame 31;

[0048] Step 3: The pneumatic assembly 34 starts to move laterally along the length direction of the frame 31 under the driving of the rotating sleeve 32 to overcome the elastic force of the return spring 36;

[0049] Step 4: The positioning assembly 35 is driven by the rotation of the rotating sleeve 32 to contact the inner wall of the wellbore annulus 1 and the outer wall of the main oil pipe 2, thereby achieving the positioning action of the packer 3;

[0050] Step five, the lateral movement of the pneumatic assembly 34 causes the first elastic membrane 37 to expand and seal against the inner wall of the wellbore annulus 1, while causing the second elastic membrane 38 to expand and seal against the outer wall of the main oil pipe 2, thereby achieving interlayer sealing between the wellbore annulus 1 and the main oil pipe 2.

[0051] See also Figure 3 and Figure 4The skeleton 31 includes an outer sleeve 311 and an inner sleeve 314 sleeved in the outer sleeve 311. A first fixing plate 312 is fixed to one end of the outer sleeve 311, and a second fixing plate 313 is fixed to the other end of the outer sleeve 311. A cover 315 is fixed to the end of the inner sleeve 314 facing the first fixing plate 312. The two ends of the first elastic membrane 37 are respectively fixed to the first fixing plate 312 and the cover 315. The two ends of the second elastic membrane 38 are respectively fixed to the second fixing plate 313 and the inner sleeve 314. The top and bottom of the outer sleeve 311 are both open. A strip-shaped limiting groove 317 is provided, and a plurality of annularly distributed arc-shaped limiting grooves 318 are provided on the second fixed disk 313. The first fixed disk 312, the cover 315 and the first elastic membrane 37 are enclosed to form a first chamber 316. The cover 315 is provided with a first through hole 3110 communicating with the first chamber 316. The first fixed disk 312, the second fixed disk 313, the outer sleeve 311 and the inner sleeve 314 are enclosed to form a second chamber 319. The first fixed disk 312 is provided with a second through hole 3111 communicating with the second chamber 319.

[0052] See also Figure 3 and Figure 5 The two ends of the rotating sleeve 32 are rotatably connected to the first fixed disk 312 and the second fixed disk 313 respectively. An arc-shaped tooth segment 321 is fixed on the outer surface of the rotating sleeve 32. The rotating sleeve 32 is provided with two spiral limiting grooves 322 corresponding to the strip limiting grooves 317.

[0053] See also Figure 3 and Figure 4 The driving device 33 includes a motor 331, which is fixed on the second fixed plate 313. The output end of the motor 331 is fixed with a gear 332 meshing with the arc-shaped tooth segment 321. The motor 331 drives the gear 332 to rotate. The meshing action between the gear 332 and the arc-shaped tooth segment 321 on the surface of the rotating sleeve 32 is as follows. Figure 2 , Figure 3 In the direction shown, the rotating sleeve 32 can be driven to rotate counterclockwise relative to the frame 31 .

[0054] See also Figure 3 and Figure 6The pneumatic assembly 34 includes a slip ring 341, one end of which is provided with a slide plate 342 which slides through the first fixed disk 312, the outer end of the slide plate 342 is fixed with a first press plug 343 which is slidably limited in the first chamber 316, and the other end of the slip ring 341 is fixed with a second press plug 344 which is slidably limited in the second chamber 319. The top and bottom of the slip ring 341 are fixed with fixed rods 345, and the two fixed rods 345 respectively penetrate the two strip limiting grooves 317 and are limited in the two spiral limiting grooves 322. When the rotating sleeve 32 rotates counterclockwise relative to the skeleton 31, the fixed rod 345 of the pneumatic assembly 34 is pushed by the spiral limiting groove 322 on the rotating sleeve 32, and the fixed rod 345 is slidably limited by the strip limiting groove 317 on the outer sleeve 311, so that the pneumatic assembly 34 can be driven to move laterally along the length direction of the skeleton 31 to overcome the elastic force of the return spring 36.

[0055] It should be noted that one end of the return spring 36 abuts against the second pressing plug 344 , and the other end of the return spring 36 abuts against the second fixing plate 313 .

[0056] See also Figure 3 and Figure 7 The positioning assembly 35 includes a first clamping block 351 and a second clamping block 352. The first clamping block 351 and the second clamping block 352 are both rotatably arranged on the second fixed disk 313 through a rotating shaft 353. The adjacent ends of the first clamping block 351 and the second clamping block 352 are provided with mutually meshing sector teeth 354. The distal ends of the first clamping block 351 and the second clamping block 352 are both fixed with anti-slip strips 358. The end of the rotating sleeve 32 close to the positioning assembly 35 is fixed with a second hinge shaft 357 limited to the arc-shaped limiting groove 318. The second hinge shaft 357 is fixed with a second hinge shaft 357. The outer end portion is hinged with a connecting rod 356, and one end of the connecting rod 356 away from the second hinge shaft 357 is hinged to the first block 351 through the first hinge shaft 355. When the rotating sleeve 32 rotates counterclockwise relative to the frame 31, it can drive the second hinge shaft 357 to rotate. The connecting rod 356 pushes the first block 351 to rotate counterclockwise around the rotating shaft 353, and the fan-shaped teeth 354 of the first block 351 and the second block 352 are engaged with each other, which can drive the second block 352 to rotate synchronously clockwise.

[0057] The working principle and use process of the present invention are as follows: before gas injection and pressurization are adopted to prevent shale gas reservoir from pressure channeling, the packer 3 is placed between the wellbore annulus 1 of the fracturing section and the interlayer of the main oil pipe 2, and the motor 331 is turned on to drive the gear 332 to rotate, and the gear 332 and the arc-shaped tooth segment 321 on the surface of the rotating sleeve 32 mesh with each other, such as Figure 2 , Figure 3In the direction shown, the rotating sleeve 32 can be driven to rotate counterclockwise relative to the skeleton 31, thereby driving the second hinge shaft 357 to rotate. The first clamping block 351 is pushed by the connecting rod 356 to rotate counterclockwise around the rotating shaft 353, and the fan-shaped teeth 354 of the first clamping block 351 and the second clamping block 352 are meshed with each other, so that the second clamping block 352 can be driven to rotate clockwise synchronously, that is, the first clamping block 351 expands from the inside to the outside to contact the inner wall of the wellbore annulus 1, and the second clamping block 352 expands from the outside to the inside to contact the outer wall of the main oil pipe 2, so as to realize the positioning action of the packer 3 between the wellbore annulus 1 and the interlayer of the main oil pipe 2;

[0058] In the above process, when the rotating sleeve 32 rotates counterclockwise relative to the skeleton 31, the spiral limiting groove 322 on the rotating sleeve 32 pushes the fixed rod 345 of the pneumatic component 34, and the strip limiting groove 317 on the outer sleeve 311 slides the fixed rod 345, so that the pneumatic component 34 can be driven to move laterally along the length direction of the skeleton 31 to overcome the elastic force of the return spring 36, and then the first pressing plug 343 moves and compresses in the first chamber 316, so that the first elastic membrane 37 expands and contacts with the inner pipe wall of the wellbore annulus 1, and the second pressing plug 344 moves and compresses in the second chamber 319, so that the second elastic membrane 38 expands and contacts with the outer pipe wall of the main oil pipe 2, thereby realizing the interlayer sealing of the wellbore annulus 1 and the main oil pipe 2.

[0059] The above are only preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A shale gas reservoir gas injection pressure channeling prevention device, comprising a wellbore annulus (1), a main oil pipe (2) located in the wellbore annulus (1), and a packer (3) placed between the wellbore annulus (1) and the main oil pipe (2), characterized in that: The packer (3) comprises: A frame (31) is sleeved on the outside of the main oil pipe (2); A rotating sleeve (32) is sleeved outside the frame (31) and is capable of rotating outside the frame (31); A driving device (33) for driving the rotating sleeve (32) to rotate relative to the frame (31); A pneumatic assembly (34) capable of moving laterally along the length direction of the frame (31) under the drive of the rotating sleeve (32); The positioning assembly (35) is synchronously driven by the rotating sleeve (32) to contact the inner wall of the wellbore annulus (1) and the outer wall of the main oil pipe (2); A return spring (36) for elastically connecting the pneumatic assembly (34) to the frame (31); A first elastic membrane (37) is expanded under the action of the pneumatic assembly (34) and is in sealing contact with the inner wall of the wellbore annulus (1); The second elastic membrane (38) is expanded under the action of the pneumatic component (34) and comes into sealing contact with the outer wall of the main oil pipe (2).

2. A shale gas reservoir gas injection pressure channeling prevention device according to claim 1, characterized in that: The skeleton (31) comprises an outer sleeve (311) and an inner sleeve (314) sleeved in the outer sleeve (311); a first fixed disk (312) is fixed to one end of the outer sleeve (311); a second fixed disk (313) is fixed to the other end of the outer sleeve (311); a sealing cover (315) is fixed to one end of the inner sleeve (314) facing the first fixed disk (312); two ends of the first elastic membrane (37) are respectively fixed to the first fixed disk (312) and the sealing cover (315); two ends of the second elastic membrane (38) are respectively fixed to the second fixed disk (313) and the inner sleeve (314); strip-shaped limiting grooves (317) are provided at the top and bottom of the outer sleeve (311); and a plurality of circularly distributed arc-shaped limiting grooves (318) are provided on the second fixed disk (313).

3. A shale gas reservoir gas injection pressure channeling prevention device according to claim 2, characterized in that: The first fixed disk (312), the sealing cover (315) and the first elastic membrane (37) enclose a first chamber (316), and the sealing cover (315) is provided with a first through hole (3110) communicating with the first chamber (316).

4. A shale gas reservoir gas injection pressure channeling prevention device according to claim 3, characterized in that: The first fixed disk (312), the second fixed disk (313), the outer sleeve (311) and the inner sleeve (314) enclose a second chamber (319), and the first fixed disk (312) is provided with a second through hole (3111) communicating with the second chamber (319).

5. A shale gas reservoir gas injection pressure channeling prevention device according to claim 4, characterized in that: The two ends of the rotating sleeve (32) are rotatably connected to the first fixed disk (312) and the second fixed disk (313), respectively; an arc-shaped tooth segment (321) is fixed to the outer surface of the rotating sleeve (32); and the rotating sleeve (32) is provided with two spiral limiting grooves (322) corresponding to the strip limiting grooves (317).

6. A shale gas reservoir gas injection pressure channeling prevention device according to claim 5, characterized in that: The driving device (33) comprises a motor (331), the motor (331) is fixed on the second fixed disk (313), and a gear (332) meshing with the arc-shaped tooth segment (321) is fixed on the output end of the motor (331).

7. A shale gas reservoir gas injection pressure channeling prevention device according to claim 5, characterized in that: The pneumatic assembly (34) comprises a slip ring (341), one end of the slip ring (341) is provided with a sliding plate (342) which slides through the first fixed plate (312), the outer end of the sliding plate (342) is fixed with a first pressing plug (343) which slides and is limited in the first chamber (316), the other end of the slip ring (341) is fixed with a second pressing plug (344) which slides and is limited in the second chamber (319), the top and bottom of the slip ring (341) are both fixed with fixing rods (345), and the two fixing rods (345) respectively penetrate through two strip limiting grooves (317) and are limited in two spiral limiting grooves (322).

8. A shale gas reservoir gas injection pressure channeling prevention device according to claim 7, characterized in that: One end of the return spring (36) abuts against the second pressing plug (344), and the other end of the return spring (36) abuts against the second fixed disk (313).

9. A shale gas reservoir gas injection pressure channeling prevention device according to claim 5, characterized in that: The positioning assembly (35) comprises a first clamping block (351) and a second clamping block (352), the first clamping block (351) and the second clamping block (352) are both rotatably arranged on the second fixed disk (313) via a rotating shaft (353), the adjacent ends of the first clamping block (351) and the second clamping block (352) are both provided with mutually meshing sector teeth (354), the distant ends of the first clamping block (351) and the second clamping block (352) are both fixed with anti-slip strips (358), the end of the rotating sleeve (32) close to the positioning assembly (35) is fixed with a second hinge shaft (357) limitedly positioned in the arc-shaped limiting groove (318), the outer end of the second hinge shaft (357) is hinged with a connecting rod (356), and the end of the connecting rod (356) away from the second hinge shaft (357) is hinged to the first clamping block (351) via the first hinge shaft (355).

10. A method for preventing pressure interference during gas injection in shale gas reservoirs, according to the device for preventing pressure interference during gas injection in shale gas reservoirs as claimed in claim 1, characterized in that: The following steps are involved: Step 1: placing a packer (3) between the wellbore annulus (1) and the interlayer of the main oil pipe (2); Step 2: turning on the driving device (33) to drive the rotating sleeve (32) to rotate relative to the frame (31); Step 3: The pneumatic assembly (34) starts to move laterally along the length direction of the frame (31) under the driving of the rotating sleeve (32) to overcome the elastic force of the return spring (36); Step 4: The positioning assembly (35) is driven by the rotation of the rotating sleeve (32) to contact the inner wall of the wellbore annulus (1) and the outer wall of the main oil pipe (2), thereby achieving the positioning action of the packer (3); Step 5: The lateral movement of the pneumatic component (34) causes the first elastic membrane (37) to expand and seal with the inner wall of the wellbore annulus (1), while causing the second elastic membrane (38) to expand and seal with the outer wall of the main oil pipe (2), thereby achieving interlayer sealing between the wellbore annulus (1) and the main oil pipe (2).

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