Interlayer pressure differential water injection process tubing

Abstract

A water injection process string under inter-layer pressure differential conditions includes tubing, a hydraulic self-locking drain anchoring device installed on the tubing, and multiple step-by-step sealing tools and bridge-type concentric profile adjustment tools installed on the tubing below the hydraulic self-locking drain anchoring device. The number of step-by-step sealing tools and bridge-type concentric profile adjustment tools is equal and they are arranged alternately. A sliding plug anti-overflow check valve is installed at the lower end of the tubing. After water injection stops, the hydraulic self-locking drain anchoring device remains anchored to prevent vertical displacement of the water injection process string and ensure that the bridge-type concentric profile adjustment tools inject water into the corresponding formation. The step-by-step sealing tools remain sealed to prevent water from flowing between formations and ensure that the pressure between formations reaches equilibrium.

Description

Technical Field

[0001] This invention relates to oilfield production equipment, and more particularly to a water injection process string under inter-layer pressure differential conditions. Background Technology

[0002] As oilfield production enters the middle and late stages, formation depletion, low inter-layer pressure, and low crude oil permeability make crude oil extraction difficult. It is necessary to use water injection process tubing to inject water into the formation in layers to control inter-layer pressure and improve extraction efficiency.

[0003] The water injection process string includes tubing, on which a hydraulic self-locking drain anchoring device is installed. Below the hydraulic self-locking drain anchoring device, multiple step-by-step sealing tools and bridge-type concentric profile adjustment tools are installed on the tubing. The number of step-by-step sealing tools and bridge-type concentric profile adjustment tools are equal and arranged alternately. A sliding plug anti-overflow check valve is installed at the lower end of the tubing. During water injection, the hydraulic self-locking drain anchoring device is anchored to the inner surface of the casing. Two adjacent step-by-step sealing tools seal the perforation sections on the casing corresponding to the respective formations. The bridge-type concentric profile adjustment tools inject water proportionally into the corresponding formations to balance the inter-layer pressure.

[0004] Traditional water injection process tubing has the following problems: After water injection stops, 1. the hydraulic self-locking oil drain anchoring device loses its anchoring function, causing the water injection process tubing to shift vertically. When water is injected again, the bridge-type concentric profile adjustment tool cannot inject water into the corresponding formation; 2. the step-by-step layered sealing tool loses its sealing function, causing water to flow between formations. When water is injected again, the pressure between formations cannot reach equilibrium. Summary of the Invention

[0005] This invention addresses the aforementioned technical problems by providing a water injection process string under inter-layer pressure differential conditions. After water injection stops, the hydraulic self-locking oil draining and anchoring device remains anchored to prevent vertical displacement of the water injection process string, ensuring that the bridge-type concentric profile adjustment tool injects water into the corresponding formation. The step-by-step layered sealing tool remains sealed to prevent water from flowing between formations, ensuring that the pressure between formations reaches equilibrium.

[0006] The technical solution of this invention is:

[0007] A water injection process string under inter-layer pressure differential conditions includes tubing, a hydraulic self-locking drain anchoring device installed on the tubing, and multiple step-by-step sealing tools and bridge-type concentric profile adjustment tools installed on the tubing below the hydraulic self-locking drain anchoring device. The number of step-by-step sealing tools and bridge-type concentric profile adjustment tools is equal and they are arranged alternately. A sliding plug anti-overflow check valve is installed at the lower end of the tubing. The key feature is that the hydraulic self-locking drain anchoring device includes an upper anchoring connector and an anchoring center tube fixedly installed vertically. The outer surface of the anchoring center tube is thicker than its lower surface. An upper outer cylinder, an anchor body, a lower outer cylinder, and an anchor are fixedly installed vertically on the outside of the anchoring center tube. The anchor body is fitted with a fixed joint. The front end of the inner circular surface of the anchor body slides up and down and is sealed to the outer circular surface of the thick diameter section of the anchoring center tube. The anchor body is provided with multiple sets of guide holes arranged vertically. Each set of guide holes is circumferentially distributed and each guide hole extends in the radial direction. An anchor tooth slides and is sealed to the guide hole. A bayonet is provided on the outer end face of the anchor tooth. A pressure plate corresponding to the bayonet is fixedly installed on the outer circular surface of the anchor body. A radial spring is installed between the inner end face of the bayonet and the pressure plate. A sealing head slides up and down and is sealed to the anchoring center tube and the lower anchoring joint. An axial spring is installed between the anchor body and the sealing head. The upper anchoring joint and the lower anchoring joint are fixedly installed to the oil pipe respectively.

[0008] The step-by-step sealing tool includes a sealing center tube, with an upper sealing connector and a lower sealing connector fixedly installed at both ends. A sealing outer cylinder, an upper pressure cap, a rubber sleeve, a release sleeve, a lower pressure cap, a connecting pipe, a seated seal sleeve, a lower piston, and a cylinder liner are fitted onto the outer surface of the sealing center tube. The upper sealing connector, sealing outer cylinder, upper pressure cap, rubber sleeve, and seated seal sleeve are sequentially fixedly installed vertically. An open retaining ring is fitted onto the outer surface of the release sleeve, and the retaining ring has fixed teeth on its outer surface. The cylinder liner is fixedly installed on the lower sealing cylinder. On the outer circular surface of the connector, the lower pressure cap, connecting pipe, seat sleeve, and lower piston are fixedly installed in sequence. The inner circular surface of the lower pressure cap is slidably installed on the outer circular surface of the rubber tube. The lower piston is slidably installed between the cylinder liner and the central tube. Moving teeth are provided on the inner circular surface of the seat sleeve and behind the unsealing sleeve. A water inlet is provided on the sealing central tube corresponding to the lower end of the lower piston. A rubber tube is fitted on the outer circular surface of the rubber tube between the upper pressure cap and the lower pressure cap. The upper sealing connector and the lower sealing connector are fixedly installed with the oil pipe respectively.

[0009] Furthermore, a starting shear pin is installed between the sealing head and the anchoring lower connector to lock the sealing head. Water injected through the anchoring central pipe pushes the sealing head upward to cut off the starting shear pin, thus unlocking the sealing head.

[0010] Furthermore, an external flow hole is provided on the rear side of the upper outer cylinder wall. The anchoring center tube is moved upward, and the thin diameter section of the anchoring center tube enters the upper outer cylinder. The water in the guide hole is discharged through the thin diameter section of the anchoring center tube and the anchor body, and through the external flow hole. The anchor teeth are reset under the action of the radial spring rebound force, and the anchoring is released.

[0011] Furthermore, a release shear pin is installed between the anchoring center tube and the upper outer cylinder to prevent the anchoring center tube from moving upwards during water injection.

[0012] Furthermore, a locking cap is threadedly installed on the outer circumference of the coarse diameter section of the anchoring center tube, located inside the upper outer cylinder. The unsealing shear pin is installed between the locking cap and the upper outer cylinder. When the water pressure inside the oil pipe is low, the anchoring center tube is moved upward, and the locking cap is pulled upward to break the unsealing shear pin; or when the water pressure inside the oil pipe is high, the anchoring center tube is rotated, and the locking cap is moved upward under the action of the thread to break the unsealing shear pin.

[0013] Furthermore, an internal flow hole is provided on the inner front side of the upper outer tube corresponding to the wall of the anchoring center tube. A floating piston is installed between the anchoring center tube and the upper outer tube and in front of the locking cap. When the anchoring center tube moves the locking cap upward, the water pressure in the upper outer tube is discharged through the internal flow hole to prevent the locking cap from being unable to move upward under the action of the water pressure in the upper outer tube.

[0014] Furthermore, a sealing shear pin is installed between the unsealing sleeve and the sealing sleeve to lock the sealing sleeve. Water injected through the sealing center tube pushes the sealing sleeve upward via the lower piston and cuts the sealing shear pin, thus unlocking the sealing sleeve.

[0015] Furthermore, a cleaning mechanism is provided between the upper pressure cap and the sealing center tube. The cleaning mechanism includes a well-washing piston that slides up and down and is sealed between the upper pressure cap and the sealing center tube. A compression spring is connected between the well-washing piston and the front end face of the sealing outer tube. The upper pressure cap is provided with circumferentially distributed upper flow holes, and the connecting pipe is provided with circumferentially distributed lower flow holes. Water is injected between the inter-layer pressure differential water injection process tubing and the casing. The injected water enters through the upper flow holes and pushes the well-washing piston upward. Then, it enters between the inter-layer pressure differential water injection process tubing and the casing through the lower flow holes. Finally, it enters the tubing, the sealing center tube, and the anchoring center tube for cleaning through the bridge-type concentric profile adjustment tool and the sliding plug anti-overflow one-way valve.

[0016] Furthermore, an unlocking mechanism is provided between the sealing center tube and the rubber tube. The unlocking mechanism includes circumferentially distributed claws located on the upper end of the unsealing sleeve. The claws are threaded onto the inner surface of the rubber tube. A boss is provided on the outer surface of the sealing center tube that fits against the inner surface of the claws. When the sealing center tube is moved upward, the claws are released from the constraint of the boss. Under the action of the rubber tube's rebound force, the seat sleeve generates a downward pushing force on the claws. The threads on the rubber tube generate a radially inward lateral force on the threads on the claws. The claws retract and separate from the rubber tube. The unlocking sleeve drives the seat sleeve to move downward, and the rubber tube contracts to release the sealing state.

[0017] The beneficial effects of this invention are:

[0018] 1. During water injection, the sealing head moves upward under water pressure and overcomes the axial spring force. The injected water enters the guide hole through the narrow section of the anchoring center tube and the anchor body. The anchor teeth move radially outward under water pressure and overcome the radial spring force. The outer surface of the anchor teeth tightly expands and clamps onto the inner surface of the casing. After the water pressure balances, the sealing head resets under the axial spring rebound force, sealing the space between the anchoring center tube and the lower anchoring joint, preventing the anchor teeth from resetting, thus completing the anchoring. After water injection stops, because the sealing head has sealed the space between the anchoring center tube and the lower anchoring joint, the hydraulic self-locking oil draining anchoring device remains in the anchored state, effectively preventing the water injection process string from shifting up and down, ensuring that the bridge-type concentric profile adjustment tool injects water into the corresponding formation.

[0019] 2. During water injection, the lower piston, under water pressure, moves the seat sleeve, connecting pipe, and lower pressure cap upwards. The rubber sleeve, squeezed by the upper and lower pressure caps, deforms radially and tightly expands onto the inner surface of the casing. Two adjacent, step-by-step sealing tools seal the perforation sections on the casing corresponding to the respective formations. The fixed and moving teeth mesh to prevent the rubber sleeve from rebounding, completing the sealing process. After water injection stops, because the fixed and moving teeth are already engaged, the rubber sleeve cannot rebound, and the step-by-step sealing tools remain in a sealing state, effectively preventing water flow between formations and ensuring pressure balance between formations. Attached Figure Description

[0020] Figure 1 This is a schematic diagram of the structure of the present invention;

[0021] Figure 2 This is a schematic diagram of the hydraulic self-locking oil draining and anchoring device in this invention;

[0022] Figure 3 yes Figure 2 Installation structure diagram of the middle anchor tooth;

[0023] Figure 4 yes Figure 3 AA section view of the middle anchor tooth;

[0024] Figure 5 yes Figure 1 A schematic diagram of the structure of a multi-stage, layered sealing tool;

[0025] In the diagram: 1-oil pipe, 2-hydraulic self-locking drain anchoring device, 3-step-by-step sealing tool, 4-bridge-type concentric profile adjustment tool, 5-sliding plug anti-overflow check valve, 201-anchoring upper connector, 202-anchoring center pipe, 203-upper outer cylinder, 204-anchor body, 205-lower outer cylinder, 206-anchoring lower connector, 207-locking cap, 208-unsealing shear pin, 209-floating piston, 210-external flow hole, 211-internal flow hole, 212-guide hole, 213-anchor tooth, 214-bayonet, 215-pressure plate, 216-radial spring, 217-sealing head, 218-starting shear pin, 2 19-Axial spring, 301-Sealing center tube, 302-Sealing upper connector, 303-Sealing lower connector, 304-Sealing outer cylinder, 305-Upper pressure cap, 306-Rubber tube, 307-Unsealing sleeve, 308-Lower pressure cap, 309-Connecting pipe, 310-Seated sleeve, 311-Lower piston, 312-Cylinder liner, 313-Claw, 314-Boss, 315-Snap ring, 316-Fixed tooth, 317-Moving tooth, 318-Seated shear pin, 319-Water inlet, 320-Rubber tube, 321-Well washing piston, 322-Compression spring, 323-Upper flow hole, 324-Lower flow hole. Detailed Implementation

[0026] like Figures 1-5As shown, a water injection process string under inter-layer pressure differential conditions includes an oil pipe 1, a hydraulic self-locking drain anchoring device 2 installed on the oil pipe 1, and multiple step-by-step sealing tools 3 and bridge-type concentric profile adjustment tools 4 installed on the oil pipe 1 below the hydraulic self-locking drain anchoring device 2. The number of step-by-step sealing tools 3 and bridge-type concentric profile adjustment tools 4 is equal and they are arranged alternately vertically. A sliding plug anti-overflow check valve 5 is installed at the lower end of the oil pipe 1. The hydraulic self-locking drain anchoring device 2 includes an upper anchoring connector 201 and an anchoring center pipe that are fixedly installed vertically. 202. The anchoring center tube 202 has a thicker outer surface and a thinner bottom surface. An upper outer cylinder 203, an anchor body 204, a lower outer cylinder 205, and an anchoring lower connector 206 are fixedly installed on the outer surface of the anchoring center tube 202. The front end of the inner diameter of the anchor body 204 slides vertically and is sealed to the outer surface of the thicker diameter section of the anchoring center tube 202. A locking cap 207 is threaded onto the outer surface of the thicker diameter section of the anchoring center tube 202, located inside the upper outer cylinder 203. A release shear pin 208 is installed between the locking cap 207 and the upper outer cylinder 203. A floating piston 209 is installed between the anchoring center tube 202 and the upper outer cylinder 203, and in front of the locking cap 207. An external flow hole 210 is provided on the rear side of the upper outer cylinder 203. An internal flow hole 211 is provided on the inner front side of the upper outer tube corresponding to the wall of the anchoring center tube 202. Multiple sets of guide holes 212 are arranged vertically on the anchor body 204. Each set of guide holes 212 is circumferentially distributed and each guide hole 212 extends in the radial direction. An anchor tooth 213 is installed in the guide hole 212 and is slidably and sealed. A locking groove is provided on the outer end face of the anchor tooth 213. 214. A pressure plate 215 corresponding to the bayonet 214 is fixedly installed on the outer circular surface of the anchor body 204. A radial spring 216 is installed between the inner end face of the bayonet 214 and the pressure plate 215. A sealing head 217 is installed between the anchoring center tube 202 and the anchoring lower joint 206 and slides up and down and seals the connection. A starting shear pin 218 is installed between the sealing head 217 and the lower joint. An axial spring 219 is installed between the anchor body 204 and the sealing head 217. The anchoring upper joint 201 and the anchoring lower joint 206 are fixedly installed with the oil pipe 1 respectively.

[0027] The step-by-step sealing tool 3 includes a sealing center tube 301. A sealing upper connector 302 and a sealing lower connector 303 are fixedly installed at the upper and lower ends of the sealing center tube 301. A sealing outer cylinder 304, an upper pressure cap 305, a rubber sleeve 306, a release sleeve 307, a lower pressure cap 308, a connecting pipe 309, a seated sealing sleeve 310, a lower piston 311, and a cylinder liner 312 are fitted onto the outer surface of the sealing center tube 301. The sealing upper connector 302, sealing outer cylinder 304, upper pressure cap 305, and rubber sleeve 306 are positioned vertically and horizontally. The components are installed sequentially and securely. The upper end of the unsealing sleeve 307 has circumferentially distributed claws 313, which are threaded onto the inner surface of the rubber tube 306. The outer surface of the sealing center tube 301 has a boss 314 that mates with the inner surface of the claws 313. An open retaining ring 315 is fitted onto the outer surface of the unsealing sleeve 307, and the outer surface of the retaining ring 315 has fixed teeth 316. The cylinder liner 312 is fixedly installed on the outer surface of the sealing lower connector 303. The lower pressure cap 308, connecting pipe 309, and seat seal are also included. The sleeve 310 and the lower piston 311 are fixedly installed vertically. The lower pressure cap 308 is slidably installed on the inner circular surface of the rubber tube 306. The lower piston 311 is slidably installed vertically and sealed between the cylinder sleeve 312 and the central tube. A movable tooth 317 is provided on the inner circular surface of the sealing sleeve 310 and behind the unsealing sleeve 307. A sealing shear pin 318 is installed between the unsealing sleeve 307 and the sealing sleeve 310. A water inlet hole 319 is provided on the sealing central tube 301 corresponding to the lower end of the lower piston 311. A rubber sleeve 320 is fitted between the upper pressure cap 305 and the lower pressure cap 308 on the outer circular surface of 06. A well-washing piston 321 is installed between the upper pressure cap 305 and the sealing center tube 301, and is installed in a sealed manner. A compression spring 322 is connected between the well-washing piston 321 and the front end face of the sealing outer tube. The upper pressure cap 305 is provided with circumferentially distributed upper flow holes 323, and the connecting tube 309 is provided with circumferentially distributed lower flow holes 324. The sealing upper connector 302 and the sealing lower connector 303 are respectively fixedly installed with the oil pipe 1.

[0028] The working principle of this invention is:

[0029] During water injection, the size of the outlet of the bridge-type concentric profile adjustment tool 4 is adjusted to regulate the amount of water injected into the corresponding formation. The water injection process string, under the pressure differential of the inter-layer, is lowered into the casing to the designated depth and water is injected through the tubing 1. Under water pressure, the sealing head 217 cuts off the starting shear pin 218 and moves upward against the elastic force of the axial spring 219. The injected water enters the guide hole 212 between the narrow section of the anchoring center pipe 202 and the anchor body 204. The anchor tooth 213 moves radially outward against the elastic force of the radial spring 216 under water pressure. The outer surface of the anchor tooth 213 tightly expands and clamps onto the inner surface of the casing. After water pressure balance, the sealing head 217, under the axial spring 219... Under the action of the rebound force, the anchoring center tube 202 and the anchoring lower joint 206 are sealed to prevent the anchor tooth 213 from resetting and to achieve anchoring. Under the action of water pressure, the lower piston 311 drives the seat sleeve 310, connecting pipe 309 and lower pressure cap 308 to move upward. The seat sleeve 310 cuts the seat shear pin 318. Under the squeezing action of the upper pressure cap 305 and lower pressure cap 308, the rubber sleeve 320 deforms radially and tightly expands and clamps itself on the inner circular surface of the casing. The two adjacent step-by-step sealing tools 3 seal the perforation section on the casing corresponding to the corresponding formation. The fixed tooth 316 and the moving tooth 317 mesh to prevent the rubber sleeve 320 from rebounding. Water injection continues, and the injected water enters the corresponding formation through the corresponding bridge-type concentric profile adjustment tool 4 and the perforation section on the casing.

[0030] During the cleaning operation, water is injected between the injection process tubing and casing under the inter-layer pressure differential. The injected water passes through the gap between the anchor teeth 213, enters through the upper flow hole 323, and pushes the well-washing piston 321 upward against the elastic force of the compression spring 322. Then, it enters between the injection process tubing and casing under the inter-layer pressure differential through the lower flow hole 324. Finally, it enters the tubing 1, the sealing center tube 301, and the anchoring center tube 202 for cleaning through the bridge-type concentric profile adjustment tool 4 and the sliding plug anti-overflow single-flow valve 5.

[0031] During disassembly, the water injection process pipe string under the interlayer pressure differential is lifted. The anchoring center pipe 202 drives the locking cap 207 to cut off the unsealing shear pin 208 and move upward. The thin section of the anchoring center pipe 202 enters the upper outer cylinder 203. The water in the guide hole 212 is discharged through the external flow hole 210 between the thin section of the anchoring center pipe 202 and the anchor body 204. The anchor teeth 213 are reset under the action of the radial spring 216, releasing the anchoring. The sealing center pipe 301 moves upward, and the locking claws... 313 is released from the restraint of the boss 314. Under the action of the rebound force of the rubber sleeve 320, the seat sleeve 310 generates a downward pushing force on the cleaver 313. The thread on the rubber sleeve 306 generates a radially inward lateral force on the thread on the cleaver 313. The cleaver 313 retracts and separates from the rubber sleeve 306. The unlocking sleeve drives the seat sleeve 310 to move down. The rubber sleeve 320 contracts and separates from the inner wall of the sleeve, releasing the blockage. Finally, the sleeve is lifted out of the water injection process pipe column under the interlayer pressure differential state.

[0032] The above are merely specific embodiments of the present invention and are not intended to limit the present invention. For those skilled in the art, the present invention can have various modifications and variations. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A water injection process string under inter-layer pressure differential conditions, comprising an oil pipe, a hydraulic self-locking drain anchoring device installed on the oil pipe, and multiple step-by-step layered sealing tools and bridge-type concentric profile adjustment tools installed on the oil pipe below the hydraulic self-locking drain anchoring device, wherein the number of step-by-step layered sealing tools and bridge-type concentric profile adjustment tools is equal and they are arranged alternately vertically, and a sliding plug anti-overflow check valve is installed at the lower end of the oil pipe, characterized in that: The hydraulic self-locking oil draining anchoring device includes an upper anchoring connector and an anchoring center tube fixedly installed at the top and bottom. The outer diameter of the anchoring center tube is thicker at the bottom and thicker at the top. An upper outer cylinder, an anchor body, a lower outer cylinder, and an lower anchoring connector are fixedly installed on the outside of the anchoring center tube. The front end of the inner diameter of the anchor body slides up and down and is sealed to the outer diameter of the thicker section of the anchoring center tube. The anchor body is provided with multiple sets of guide holes arranged vertically. Each set of guide holes is circumferentially distributed and each guide hole extends in the radial direction. An anchor tooth slides and is sealed to the guide hole. A bayonet is provided on the outer end face of the anchor tooth. A pressure plate is fixedly installed on the outer diameter of the anchor body. The pressure plate corresponds to the bayonet. A radial spring is installed between the inner end face of the bayonet and the pressure plate. A sealing head slides up and down and is sealed to the anchoring center tube and the lower anchoring connector. An axial spring is installed between the anchor body and the sealing head. The upper anchoring connector and the lower anchoring connector are fixedly installed to the oil pipe respectively. The step-by-step sealing tool includes a sealing center tube, with an upper sealing connector and a lower sealing connector fixedly installed at both ends. A sealing outer cylinder, an upper pressure cap, a rubber sleeve, a release sleeve, a lower pressure cap, a connecting pipe, a seated seal sleeve, a lower piston, and a cylinder liner are fitted onto the outer surface of the sealing center tube. The upper sealing connector, sealing outer cylinder, upper pressure cap, rubber sleeve, and seated seal sleeve are sequentially fixedly installed vertically. An open retaining ring is fitted onto the outer surface of the release sleeve, and the retaining ring has fixed teeth on its outer surface. The cylinder liner is fixedly installed on the lower sealing cylinder. On the outer circular surface of the connector, the lower pressure cap, connecting pipe, seat sleeve, and lower piston are fixedly installed in sequence. The inner circular surface of the lower pressure cap is slidably installed on the outer circular surface of the rubber tube. The lower piston is slidably installed between the cylinder liner and the central tube. Moving teeth are provided on the inner circular surface of the seat sleeve and behind the unsealing sleeve. A water inlet is provided on the sealing central tube corresponding to the lower end of the lower piston. A rubber tube is fitted on the outer circular surface of the rubber tube between the upper pressure cap and the lower pressure cap. The upper sealing connector and the lower sealing connector are fixedly installed with the oil pipe respectively.

2. The water injection process tubing under interlayer pressure differential as described in claim 1, characterized in that: Install the starting shear pin between the sealing head and the anchoring lower joint.

3. The water injection process tubing under interlayer pressure differential as described in claim 1, characterized in that: An external flow hole is provided on the rear side of the upper outer cylinder wall.

4. The water injection process tubing under interlayer pressure differential as described in claim 1, characterized in that: Install unsealing shear pins between the anchoring center tube and the upper outer cylinder.

5. The water injection process tubing under interlayer pressure differential as described in claim 1, characterized in that: A locking cap is threadedly installed on the outer circumference of the thick-diameter section of the anchoring center tube, located inside the upper outer cylinder, and the unsealing shear pin is installed between the locking cap and the upper outer cylinder.

6. The interlayer pressure differential water injection process tubing according to claim 5, characterized in that: An internal flow hole is provided on the inner front side of the upper outer tube corresponding to the wall of the anchoring center tube, and a floating piston is installed between the anchoring center tube and the upper outer tube and in front of the locking cap.

7. The water injection process tubing under interlayer pressure differential as described in claim 1, characterized in that: Install a sealing clip between the unsealing sleeve and the sealing sleeve.

8. The water injection process tubing under interlayer pressure differential as described in claim 1, characterized in that: A cleaning mechanism is provided between the upper pressure cap and the sealing center tube. The cleaning mechanism includes a well-washing piston that slides up and down and is sealed between the upper pressure cap and the sealing center tube. A compression spring is connected between the well-washing piston and the front end face of the sealing outer tube. The upper pressure cap is provided with circumferentially distributed upper flow holes, and the connecting tube is provided with circumferentially distributed lower flow holes.

9. The water injection process tubing under interlayer pressure differential as described in claim 1, characterized in that: An unlocking mechanism is provided between the sealing center tube and the rubber tube. The unlocking mechanism includes circumferentially distributed claws located at the upper end of the unsealing sleeve. The claws are threaded onto the inner circular surface of the rubber tube. A boss is provided on the outer circular surface of the sealing center tube to fit against the inner circular surface of the claws.

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