Water injection process pipe column in interlayer pressure difference state

Abstract

An interlayer pressure difference state water injection process pipe column comprises an oil pipe, a hydraulic self-locking oil drainage anchoring device is installed on the oil pipe, and a plurality of step-by-step layered plugging tools and bridge type concentric profile control tools are installed on the oil pipe and located below the hydraulic self-locking oil drainage anchoring device. The number of the step-by-step layered plugging tools and the number of the bridge type concentric profile control tools are equal, the step-by-step layered plugging tools and the bridge type concentric profile control tools are alternately arranged up and down, a sliding plugging anti-overflow check valve is installed at the lower end of an oil pipe, after water injection is stopped, the hydraulic self-locking oil drainage anchoring device is still kept in an anchoring state, a water injection process pipe column is prevented from moving up and down, and it is guaranteed that the bridge type concentric profile control tools inject water into corresponding stratums; and the step-by-step layering plugging tool still keeps a plugging state, mutual circulation of water between stratums is prevented, and it is guaranteed that the pressure between the stratums is balanced.

Description

Technical Field

[0001] The invention relates to oil field production equipment, in particular to a water injection process pipe column in an interlayer pressure difference state. Background Art

[0002] When oil production in an oil field enters the middle and late stages, the formation is depleted, the interlayer pressure is low, the crude oil permeability is low, and crude oil production is difficult. It is necessary to use water injection process tubing to inject water into the formation in layers to control the interlayer pressure and improve production efficiency.

[0003] The water injection process string includes an oil pipe, a hydraulic self-locking oil leakage anchor device is installed on the oil pipe, and a plurality of step-by-step layered plugging tools and bridge-type concentric profile adjustment tools are installed on the oil pipe below the hydraulic self-locking oil leakage anchor device. The step-by-step layered plugging tools and bridge-type concentric profile adjustment tools are equal in number and arranged alternately up and down, and a sliding plugging anti-overflow check valve is installed at the lower end of the oil pipe. During water injection, the hydraulic self-locking oil leakage anchor device is anchored on the inner circular surface of the casing, and two upper and lower adjacent step-by-step layered plugging tools block the perforation sections corresponding to the corresponding formations on the casing up and down, and the injected water is injected into the corresponding formation in equal proportions through the bridge-type concentric profile adjustment tool to balance the interlayer pressure between the formations.

[0004] The traditional water injection process string has the following problems: after the water injection is stopped, 1. The hydraulic self-locking oil leakage anchoring device loses its anchoring effect, causing the water injection process string to move up and down. 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 plugging tool loses its plugging effect, causing water between formations to flow between each other. When water is injected again, the pressure between formations cannot reach balance. Summary of the invention

[0005] The present invention is to solve the above technical problems and provides a water injection process string in an interlayer pressure difference state. After the water injection is stopped, the hydraulic self-locking oil leakage anchoring device still maintains the anchoring state to prevent the water injection process string from moving up and down, ensuring that the bridge-type concentric profile control tool injects water into the corresponding formation; the step-by-step layered plugging tool still maintains the plugging state to prevent the water between the formations from circulating between each other, ensuring that the pressure between the formations is balanced.

[0006] The technical solution of the present invention is:

[0007] A water injection process pipe string under interlayer pressure difference state, comprising an oil pipe, a hydraulic self-locking oil leakage anchoring device installed on the oil pipe, a plurality of step-by-step layered plugging tools and bridge-type concentric profile adjustment tools installed on the oil pipe below the hydraulic self-locking oil leakage anchoring device, the step-by-step layered plugging tools and the bridge-type concentric profile adjustment tools are equal in number and are alternately arranged up and down, a sliding plugging anti-overflow check valve is installed at the lower end of the oil pipe, and the special feature is that the hydraulic self-locking oil leakage anchoring device comprises an anchoring upper joint and an anchoring center pipe fixedly installed up and down, the outer circumference of the anchoring center pipe is thick on the outer circumference and thin on the bottom, an upper outer tube, an anchor body, a lower outer tube and an anchor body fixedly installed up and down are sleeved outside the anchoring center pipe A lower joint is fixed, the inner circular face end of the anchor body slides up and down and is sealed with the outer circular face of the thick pipe section of the anchor center pipe, a plurality of groups of guide holes arranged up and down are provided on the anchor body, each group of guide holes is distributed circumferentially, each guide hole extends in the radial direction, the anchor teeth are slid and sealed in the guide holes, a bayonet is provided on the outer end face of the anchor teeth, a pressure plate corresponding to the bayonet is fixedly installed on the outer circular face of the anchor body, a radial spring is installed between the inner end face of the bayonet and the pressure plate, a sealing head is slid up and down and is sealed between the anchor center pipe and the anchor lower joint, an axial spring is installed between the anchor body and the sealing head, the anchor upper joint and the anchor lower joint are fixedly installed with the oil pipe respectively;

[0008] The step-by-step layered plugging tool comprises a plugging center tube, an upper plugging joint and a lower plugging joint are fixedly installed at the upper and lower ends of the plugging center tube, and a plugging outer tube, an upper pressure cap, a rubber tube, an unsealing sleeve, a lower pressure cap, a connecting tube, a seat sleeve, a lower piston and a cylinder sleeve are mounted on the outer cylindrical surface of the plugging center tube. The upper plugging joint, the plugging outer tube, the upper pressure cap, the rubber tube and the seat sleeve are fixedly installed in sequence from top to bottom, an open clamping ring is clamped on the outer cylindrical surface of the unsealing sleeve, and fixed teeth are arranged on the outer cylindrical surface of the clamping ring; the cylinder sleeve is fixedly mounted on the plugging lower The outer cylindrical surface of the joint, the lower pressure cap, the connecting pipe, the seat sleeve and the lower piston are fixedly installed in sequence up and down, the inner cylindrical surface of the lower pressure cap is slidably installed on the outer cylindrical surface of the rubber tube up and down, the lower piston is slidably installed up and down and sealed between the cylinder sleeve and the center tube, and movable teeth are provided on the inner cylindrical surface of the seat sleeve and behind the unsealing sleeve. A water inlet hole is provided on the sealing center tube corresponding to the lower end of the lower piston, and a rubber tube is installed between the upper pressure cap and the lower pressure cap on the outer cylindrical surface of the rubber tube, and the sealing upper joint and the sealing lower joint are fixedly installed with the oil pipe respectively.

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

[0010] Furthermore, an external flow hole is provided on the rear side of the wall of the upper outer tube, the anchoring central tube is moved upward, the thin tube section of the anchoring central tube enters the upper outer tube, and the water in the guide hole is discharged through the thin tube section of the anchoring central tube and the anchor body and the external flow hole, and the anchor tooth is reset under the action of the radial spring rebound force to release the anchoring.

[0011] Furthermore, unsealing shear pins are installed between the anchoring center pipe and the upper outer tube to prevent the anchoring center pipe from moving upward during water injection.

[0012] Furthermore, a locking cap is installed through a thread on the outer circumferential surface of the thick pipe section of the anchored central tube and located inside the upper outer tube, and the unsealing shear pins are installed between the locking cap and the upper outer tube. When the water pressure in the oil pipe of the anchored central tube is low, the anchored central tube is moved upward, and the locking cap pulls the unsealing shear pins upward to break; or when the water pressure in the oil pipe of the anchored central tube is high, the anchored central tube is rotated, and the locking cap moves upward under the action of the thread to break the unsealing shear pins.

[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, and 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 drives the locking cap to move upward, the water pressure in the upper outer tube is discharged through the internal flow hole, so as 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 seat seal shear pin is installed between the unlocking sleeve and the seat seal sleeve to lock the seat seal sleeve. The water injected through the plugging central pipe pushes the seat seal sleeve upward through the lower piston and cuts off the seat seal shear pin, thereby unlocking the seat seal sleeve.

[0015] Furthermore, a cleaning mechanism is arranged between the upper pressure cap and the plugging center tube, and the cleaning mechanism comprises a well washing piston which slides up and down and is sealingly installed between the upper pressure cap and the plugging center tube, a compression spring is connected between the well washing piston and the front end surface of the plugging 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, and water is injected between the water injection process string and the casing in the state of interlayer pressure difference, the injected water enters through the upper flow hole and pushes the well washing piston upward, and then enters between the water injection process string and the casing in the state of interlayer pressure difference through the lower flow hole, and finally enters the oil pipe, the plugging center tube and the anchoring center tube through the bridge-type concentric profile adjustment tool and the sliding plugging anti-overflow check valve for cleaning.

[0016] Furthermore, an unlocking mechanism is arranged between the sealing center tube and the rubber tube, and the unlocking mechanism includes a claw which is arranged at the upper end of the unlocking sleeve and distributed circumferentially, the claw is installed on the inner circular surface of the rubber tube through a thread, and a boss which fits with the inner circular surface of the claw is arranged on the outer circular surface of the sealing center tube. The sealing center tube is moved upward, and the claw is separated from the restraint of the boss. Under the action of the rebound force of the rubber tube, the seat sleeve generates a downward thrust on the claw, and the thread on the rubber tube generates a radial inward lateral component of force on the thread on the claw, so that the claw shrinks inward and separates from the rubber tube, and 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 the present invention are:

[0018] 1. During water injection, the sealing head moves upward under the action of water pressure and overcomes the axial spring force. The injected water enters the guide hole between the thin tube section of the anchor center pipe and the anchor body. The anchor teeth move radially outward under the action of water pressure to overcome the radial spring force. The outer cylindrical surface of the anchor teeth is tightly clamped on the inner cylindrical surface of the casing. After the water pressure is balanced, the sealing head is reset under the action of the axial spring rebound force to seal the anchor center pipe and the anchor lower joint to prevent the anchor teeth from resetting and complete the anchoring. After stopping the water injection, because the sealing head has sealed the anchor center pipe and the anchor lower joint, the hydraulic self-locking oil leakage anchor device still remains in the anchored state, effectively preventing the up and down displacement of the water injection process string, and ensuring that the bridge-type concentric profile control tool injects water into the corresponding formation.

[0019] 2. During water injection, the lower piston drives the seat sleeve, the connecting pipe and the lower pressure cap upward under the action of water pressure. The rubber tube is deformed radially outward under the squeezing action of the upper and lower pressure caps and tightly expands on the inner surface of the casing. The two adjacent step-by-step layered plugging tools block the perforation sections on the casing corresponding to the corresponding formations. The fixed teeth and the movable teeth are engaged to prevent the rubber tube from rebounding and complete the plugging. After stopping water injection, the rubber tube cannot rebound because the fixed teeth and the movable teeth are engaged. The step-by-step layered plugging tool still maintains the plugging state, effectively preventing the water between the formations from flowing mutually and ensuring that the pressure between the formations is balanced. BRIEF DESCRIPTION OF THE DRAWINGS

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

[0021] Figure 2 It is a structural schematic diagram of the hydraulic self-locking oil leakage anchor device in the present 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 the step-by-step layered plugging tool;

[0025] In the figure: 1-oil pipe, 2-hydraulic self-locking oil leakage anchor device, 3-step-by-step layered plugging tool, 4-bridge-type concentric profile control tool, 5-sliding plugging anti-overflow check valve, 201-anchor upper joint, 202-anchor center pipe, 203-upper outer cylinder, 204-anchor body, 205-lower outer cylinder, 206-anchor lower joint, 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-pressing plate, 216-radial spring, 217-sealing head, 218-starting shear pin, 2 19-axial spring, 301-blocking center tube, 302-blocking upper joint, 303-blocking lower joint, 304-blocking outer tube, 305-upper pressure cap, 306-rubber tube, 307-unsealing sleeve, 308-lower pressure cap, 309-connecting pipe, 310-seat sleeve, 311-lower piston, 312-cylinder sleeve, 313-claw, 314-boss, 315-retaining ring, 316-fixed teeth, 317-moving teeth, 318-seat sealing shear nails, 319-water inlet hole, 320-rubber tube, 321-well washing piston, 322-compression spring, 323-upper flow hole, 324-lower flow hole. DETAILED DESCRIPTION

[0026] like Figure 1-Figure 5As shown, a water injection process string in an interlayer pressure differential state comprises an oil pipe 1, a hydraulic self-locking oil leakage anchor device 2 is installed on the oil pipe 1, and a plurality of step-by-step layered plugging tools 3 and a bridge-type concentric profile control tool 4 are installed below the hydraulic self-locking oil leakage anchor device 2 on the oil pipe 1. The step-by-step layered plugging tools 3 and the bridge-type concentric profile control tools 4 are equal in number and are alternately arranged up and down. A sliding plugging anti-overflow check valve 5 is installed at the lower end of the oil pipe 1. The hydraulic self-locking oil leakage anchor device 2 comprises an anchor upper joint 201 fixedly installed up and down and an anchor center pipe 202, the outer circumference of the anchoring center tube 202 is thick at the top and thin at the bottom, and an upper outer tube 203, an anchor body 204, a lower outer tube 205 and an anchoring lower joint 206 are fixedly installed on the outer surface of the anchoring center tube 202, and the front end of the inner circumference of the anchor body 204 slides up and down with the outer circumference of the thick pipe diameter section of the anchoring center tube 202 and is sealed. A locking cap 207 is threadedly installed on the outer circumference of the thick pipe diameter section of the anchoring center tube 202 and located in the upper outer tube 203, and an unsealing shear nail 208 is installed between the locking cap 207 and the upper outer tube 203. A floating piston 209 is installed between the anchoring center tube 202 and the upper outer tube 203 and in front of the locking cap 207. An outer flow hole 210 is provided on the rear side of the tube wall of the upper outer tube 203. An inner flow hole 211 is provided on the inner front side of the tube wall of the anchoring center tube 202 corresponding to the upper outer tube. A plurality of groups of guide holes 212 arranged up and down are provided on the anchor body 204. Each group of guide holes 212 is distributed circumferentially. Each guide hole 212 extends in the radial direction. An anchor tooth 213 is slidably and sealedly installed in the guide hole 212. A bayonet is provided on the outer end surface of the anchor tooth 213 214, a pressure plate 215 corresponding to the bayonet 214 is fixedly installed on the outer circumferential surface of the anchor body 204, a radial spring 216 is installed between the inner end surface of the bayonet 214 and the pressure plate 215, a sealing head 217 is slid up and down and sealed between the anchor center pipe 202 and the anchor lower joint 206, a starting shear nail 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, and the anchor upper joint 201 and the anchor lower joint 206 are fixedly installed with the oil pipe 1 respectively;

[0027] The step-by-step layered plugging tool 3 includes a plugging center tube 301, a plugging upper joint 302 and a plugging lower joint 303 are fixedly installed at the upper and lower ends of the plugging center tube 301, and a plugging outer tube 304, an upper pressure cap 305, a rubber tube 306, a de-sealing sleeve 307, a lower pressure cap 308, a connecting tube 309, a seat sleeve 310, a lower piston 311 and a cylinder sleeve 312 are mounted on the outer circumference of the plugging center tube 301. The unsealing sleeve 307 is fixedly installed in sequence, and a circumferentially distributed claw 313 is provided at the upper end of the unsealing sleeve 307. The claw 313 is installed on the inner surface of the rubber tube 306 through a thread. A boss 314 that fits the inner surface of the claw 313 is provided on the outer surface of the plugging center tube 301. An open clamping ring 315 is clamped on the outer surface of the unsealing sleeve 307, and a fixed tooth 316 is provided on the outer surface of the clamping ring 315; the cylinder sleeve 312 is fixedly installed on the outer surface of the plugging lower joint 303, and the lower pressure cap 308, the connecting pipe 309, and the seat seal are fixedly installed. The sleeve 310 and the lower piston 311 are fixedly installed up and down in sequence. The inner surface of the lower pressure cap 308 is slidably installed on the outer surface of the rubber tube 306. The lower piston 311 is slidably installed up and down and sealed between the cylinder sleeve 312 and the center tube. A movable tooth 317 is provided on the inner surface of the seat seal sleeve 310 and behind the unsealing sleeve 307. A seat seal shear nail 318 is installed between the unsealing sleeve 307 and the seat seal sleeve 310. A water inlet hole 319 is provided on the sealing center tube 301 corresponding to the lower end of the lower piston 311. 06 The outer cylindrical surface is located between the upper pressure cap 305 and the lower pressure cap 308, and the rubber cylinder 320 is sleeved. The well washing piston 321 is slidably installed up and down and sealed between the upper pressure cap 305 and the plugging center pipe 301. The compression spring 322 is connected between the well washing piston 321 and the front end surface of the plugging outer pipe. The upper pressure cap 305 is provided with circumferentially distributed upper flow holes 323, and the connecting pipe 309 is provided with circumferentially distributed lower flow holes 324. The plugging upper joint 302 and the plugging lower joint 303 are fixedly installed with the oil pipe 1 respectively.

[0028] The working principle of the present invention is:

[0029] During water injection operation, the size of the water outlet of the bridge-type concentric profile control tool 4 is adjusted, thereby adjusting the amount of water injected into the corresponding formation. The water injection process string in the interlayer pressure differential state is lowered into the specified depth of the casing and water is injected through the oil pipe 1. The sealing head 217 cuts off the start shear nail 218 under the action of water pressure and overcomes the elastic force of the axial spring 219 to move upward. The injected water enters the guide hole 212 between the thin tube diameter section of the anchor center pipe 202 and the anchor body 204. The anchor teeth 213 move radially outward under the action of water pressure to overcome the elastic force of the radial spring 216. The outer cylindrical surface of the anchor teeth 213 is tightly expanded on the inner cylindrical surface of the casing. After the water pressure is balanced, the sealing head 217 is pressed against the axial spring 219 and moves upward. 19 resets under the action of the rebound force to seal the anchor center pipe 202 and the anchor lower joint 206, preventing the anchor teeth 213 from resetting and achieving anchoring; the lower piston 311 drives the seat seal sleeve 310, the connecting pipe 309 and the lower pressure cap 308 to move upward under the action of water pressure, the seat seal sleeve 310 cuts off the seat seal shear nail 318, the rubber tube 320 is radially deformed and tightly expanded on the inner surface of the casing under the extrusion of the upper pressure cap 305 and the lower pressure cap 308, and the upper and lower adjacent step-by-step layered plugging tools 3 seal the perforation section corresponding to the corresponding formation on the casing up and down, and the fixed teeth 316 and the movable teeth 317 are engaged to prevent the rubber tube 320 from rebounding. Continue to inject water, and the injected water enters the corresponding formation through the corresponding bridge-type concentric profile control tool 4 and the perforation section on the casing in turn.

[0030] During the cleaning operation, water is injected between the water injection process string and the casing in the state of pressure difference between the layers. The injected water passes through the gap between the anchor teeth 213, enters through the upper flow hole 323 and overcomes the elastic force of the compression spring 322 to push the well washing piston 321 upward, and then enters between the water injection process string and the casing in the state of pressure difference between the layers through the lower flow hole 324, and finally enters the oil pipe 1, blocks the central pipe 301 and anchors the central pipe 202 through the bridge-type concentric profile control tool 4 and the sliding plugging anti-overflow check valve 5 for cleaning.

[0031] During the disassembly operation, the water injection process string in the pressure difference state between the layers is lifted, the anchoring center pipe 202 drives the locking cap 207 to cut off the unsealing shear nail 208 and move up, the thin tube section of the anchoring center pipe 202 enters the upper outer tube 203, and the water in the guide hole 212 is discharged through the thin tube section of the anchoring center pipe 202 and the anchor body 204 and the external flow hole 210, and the anchor tooth 213 is reset under the rebound force of the radial spring 216 to release the anchor; the plugging center pipe 301 moves up, and the claws 313 breaks away from the restraint of the boss 314, and under the action of the rebound force of the rubber cylinder 320, the seat sleeve 310 generates a downward thrust on the claw 313, and the thread on the rubber cylinder tube 306 generates a radial inward lateral component of force on the thread on the claw 313, and the claw 313 shrinks and separates from the rubber cylinder tube 306. The unlocking sleeve drives the seat sleeve 310 to move downward, and the rubber cylinder 320 shrinks and separates from the inner wall of the casing to release the blockage. Finally, the casing is lifted out of the water injection process string in the pressure difference state between the layers.

[0032] The above are only specific embodiments of the present invention and are not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A water injection process string in the state of interlayer pressure difference, comprising an oil pipe, a hydraulic self-locking oil leakage anchor device is installed on the oil pipe, and a plurality of step-by-step layered plugging tools and bridge-type concentric profile control tools are installed below the hydraulic self-locking oil leakage anchor device on the oil pipe, wherein the number of the step-by-step layered plugging tools and the bridge-type concentric profile control tools is equal and they are arranged alternately up and down, and a sliding plugging anti-overflow check valve is installed at the lower end of the oil pipe, characterized in that: The hydraulic self-locking oil leakage anchoring device comprises an upper anchoring joint and an anchoring center tube which are fixedly installed up and down, the outer circumferential surface of the anchoring center tube is thick at the top and thin at the bottom, an upper outer tube, an anchor body, a lower outer tube and an anchoring lower joint which are fixedly installed up and down are sleeved outside the anchoring center tube, the front end of the inner circumferential surface of the anchor body slides up and down and is sealed with the outer circumferential surface of the thick pipe diameter section of the anchoring center tube, a plurality of groups of guide holes arranged up and down are provided on the anchor body, each group of guide holes is distributed circumferentially, each guide hole extends in a radial direction, an anchor tooth is slidably and sealably installed in the guide hole, a bayonet is provided on the outer end surface of the anchor tooth, a pressure plate corresponding to the bayonet is fixedly installed on the outer circumferential surface of the anchor body, a radial spring is installed between the inner end surface of the bayonet and the pressure plate, a sealing head is slidably and sealably installed between the anchoring center tube and the anchoring lower joint, an axial spring is installed between the anchor body and the sealing head, the upper anchoring joint and the anchoring lower joint are fixedly installed with the oil pipe respectively; The step-by-step layered plugging tool comprises a plugging center tube, an upper plugging joint and a lower plugging joint are fixedly installed at the upper and lower ends of the plugging center tube, and a plugging outer tube, an upper pressure cap, a rubber tube, an unsealing sleeve, a lower pressure cap, a connecting tube, a seat sleeve, a lower piston and a cylinder sleeve are mounted on the outer cylindrical surface of the plugging center tube. The upper plugging joint, the plugging outer tube, the upper pressure cap, the rubber tube and the seat sleeve are fixedly installed in sequence from top to bottom, an open clamping ring is clamped on the outer cylindrical surface of the unsealing sleeve, and fixed teeth are arranged on the outer cylindrical surface of the clamping ring; the cylinder sleeve is fixedly mounted on the plugging lower The outer cylindrical surface of the joint, the lower pressure cap, the connecting pipe, the seat sleeve and the lower piston are fixedly installed in sequence up and down, the inner cylindrical surface of the lower pressure cap is slidably installed on the outer cylindrical surface of the rubber tube up and down, the lower piston is slidably installed up and down and sealed between the cylinder sleeve and the center tube, and movable teeth are provided on the inner cylindrical surface of the seat sleeve and behind the unsealing sleeve. A water inlet hole is provided on the sealing center tube corresponding to the lower end of the lower piston, and a rubber tube is installed between the upper pressure cap and the lower pressure cap on the outer cylindrical surface of the rubber tube, and the sealing upper joint and the sealing lower joint are fixedly installed with the oil pipe respectively.

2. The interlayer pressure differential state water injection process string according to claim 1, characterized in that: Install the starter shear pins between the sealing head and the anchor lower joint.

3. The interlayer pressure differential state water injection process string according to claim 1, characterized in that: An outflow hole is arranged on the rear side of the wall of the upper outer cylinder.

4. The interlayer pressure differential state water injection process string according to claim 1, characterized in that: Install unsealing shear nails between the anchoring center tube and the upper outer tube.

5. The interlayer pressure differential state water injection process string according to claim 1, characterized in that: A locking cap is installed through threads on the outer circumferential surface of the thick pipe section of the anchored central pipe and located in the upper outer tube, and the unsealing shear nail is installed between the locking cap and the upper outer tube.

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

7. The interlayer pressure differential state water injection process string according to claim 1, characterized in that: Install the sealing shear nails between the unsealing sleeve and the sealing sleeve.

8. The interlayer pressure differential state water injection process string according to claim 1, characterized in that: A cleaning mechanism is arranged between the upper pressure cap and the plugging central tube, and the cleaning mechanism comprises a well-washing piston which slides up and down and is sealed and installed between the upper pressure cap and the plugging central tube, a compression spring is connected between the well-washing piston and the front end surface of the plugging 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 interlayer pressure differential state water injection process string according to claim 1, characterized in that: An unlocking mechanism is arranged between the sealing center tube and the rubber tube, and the unlocking mechanism includes claws arranged at the upper end of the unsealing sleeve and distributed circumferentially. The claws are installed on the inner circular surface of the rubber tube through threads, and a boss is arranged on the outer circular surface of the sealing center tube to fit with the inner circular surface of the claws.

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