A water shutoff packer structure

Abstract

The application relates to the technical field of oil drilling construction, in particular to a water plugging packer structure which comprises an inner central pipe, a top limiting assembly, an upper extrusion mechanism, an outer central pipe, a rubber sleeve, a lower extrusion mechanism and a bottom joint, the end of a seat pad is provided with an upper sand prevention assembly, the end of a well washing seat is provided with a lower sand prevention assembly, and the inside of the well washing seat is provided with a reverse well washing assembly. The upper extrusion mechanism and the lower extrusion mechanism are arranged, pressure can be applied to both ends of the rubber sleeve simultaneously during use, the sealing effect is improved, and the service life of the rubber sleeve is prolonged. The upper sand prevention assembly and the lower sand prevention assembly are arranged, the impact and friction of the rubber sleeve caused by the mud sand are reduced, the service life of the rubber sleeve and the sealing property of the seat seal are improved, the broken bevel gears, the coarse broken gear rings and the fine broken gear rings outside the sand prevention baffle are arranged, the granularity of the mud sand is gradually reduced when the mud sand passes through the reverse well washing channel, and the abrasion of the inner wall of the outer central pipe and the outer wall of the inner central pipe is reduced.

Description

Technical Field

[0001] This invention relates to the field of oil drilling construction technology, specifically to a water shut-off packer structure. Background Technology

[0002] During oil and gas field development, as extraction time increases, the water cut in oil wells rises continuously, severely impacting oil recovery. Water-shutting packers are core downhole tools for achieving stratified water shut-off and stratified extraction in oil and water wells; their performance directly determines the effectiveness and duration of water shut-off operations. A typical water-shutting packer's internal structure works collaboratively to complete the entire process of setting, sealing, and unsealing. Setting mechanism: This is the part that initiates the packer's operation. Hydraulic setting is common; by pressurizing the tubing string, the fluid pushes the piston upward, compressing the rubber sleeve and causing it to expand radially, tightly adhering to the casing's inner wall, thus completing the setting. Some packers use mechanical setting, relying on the impact force or rotation of the lowered tubing string to achieve setting. Locking mechanism: After setting, this ensures the rubber sleeve remains compressed and does not automatically rebound. This is a one-way locking device that ensures the packer maintains stable sealing performance during long-term downhole operations. Unsealing mechanism: This plays a role when the tubing string needs to be retrieved. Typically, by lifting the tubing string, cutting the release pin, and releasing the locking mechanism, the rubber sleeve returns to its original shape under its own elasticity, allowing the packer to be successfully released. For multi-stage packers, a step-by-step release mechanism is also designed to avoid excessive load during a single release, which could lead to difficulties in pulling the tubing back up.

[0003] Existing water-blocking packers have the following technical defects: First, the setting reliability is insufficient: Traditional hydraulic setting structures are mostly driven by a single hydraulic cylinder, and the compression force of the rubber sleeve is uneven, which easily leads to problems such as incomplete setting and sealing failure. Secondly, poor sand control performance: During downhole operations, formation sand and impurities can easily enter the rubber sleeve seat, causing wear and affecting the service life of the rubber sleeve and the sealing performance of the seat. In addition, during the backwashing process, impurities and sand particles in the wellbore can easily clog the packer flow channel, affecting the well washing efficiency and even damaging the sealing components, thus reducing the service life of the tools. Summary of the Invention

[0004] To address the shortcomings of existing technologies, this invention provides a water-blocking packer structure that improves the sealing effect, reduces the erosion and wear of the rubber sleeve by silt, breaks up the silt to improve the efficiency of backwashing, and prevents backwashing blockage, thus solving the problems mentioned in the background art.

[0005] To achieve the above objectives, the present invention provides the following technical solution: a water-blocking seal structure, comprising an inner central tube, a top limiting component, an upper extrusion mechanism, an outer central tube, a rubber cylinder, a lower extrusion mechanism, and a bottom connector. The top limiting component is installed at the top end of the inner central tube, and the bottom connector is installed at the bottom end of the inner central tube. The end of the upper extrusion mechanism abuts against the bottom of the top limiting component. The rubber cylinder is disposed outside the outer central tube. The bottom of the upper extrusion mechanism abuts against the rubber cylinder, and the top of the lower extrusion mechanism abuts against the rubber cylinder. The top limiting component, the upper extrusion mechanism, the outer central tube, and the lower extrusion mechanism are all disposed outside the inner central tube. Two sets of pressurization ports are provided on the inner wall of the inner central tube; The upper extrusion mechanism includes an upper hydraulic cylinder, an upper fixed piston, a locking tube, an upper snap ring seat, a snap ring bearing sleeve, and a seat pad. The end of the seat pad is provided with an upper sand-proof component. Multiple rubber tubes are provided and are fitted onto the outside of the outer central tube, with spacer rings between adjacent rubber tubes; The lower extrusion mechanism includes a lower hydraulic cylinder, a lower fixed piston, a lower snap ring seat, a well washing seat, and a backwashing assembly. The end of the well washing seat is equipped with a lower sand-prevention assembly, and the inside of the well washing seat is equipped with a backwashing assembly.

[0006] Preferably, the top limiting assembly includes a top connector, an adjusting ring, and a top seat. The top connector is threaded to the end of the inner central tube, the inner wall of the top connector is threaded to the outer wall of the end of the inner central tube, the outer wall of the top connector is threaded to the adjusting ring, the top of the top seat abuts against the bottom of the adjusting ring, and the bottom of the top seat is inserted into the top of the upper hydraulic cylinder.

[0007] Preferably, the upper fixed piston is located inside the upper hydraulic cylinder, and the upper fixed piston is connected to the outer wall of the inner central tube by a thread. A sealing ring is provided between the bottom end of the upper hydraulic cylinder and the outer wall of the inner central tube, and a set of pressure ports is located between the bottom of the upper hydraulic cylinder and the upper fixed piston.

[0008] Preferably, the inner wall of the lock tube is provided with several layers of ratchet teeth arranged in a ring. The upper snap ring seat is located inside the lock tube and is provided with several snap rings. The snap rings and ratchet teeth are engaged. One end of the upper snap ring seat is provided with a snap ring support sleeve. The end of the outer center tube is provided with an external thread. The end of the snap ring support sleeve is threaded to the end of the outer center tube. The snap ring support sleeve is located inside the seat cushion. The outer wall of the seat cushion is equipped with a seat sealing scissor. The outer wall of the snap ring support sleeve is provided with an annular groove. The end of the seat sealing scissor is inserted into the annular groove of the snap ring support sleeve.

[0009] Preferably, the upper sand-proof component includes an axial groove formed at the end of the seat pad, a sliding seat slidably disposed inside the axial groove, a hinge rod installed on the inner wall of the sliding seat, a sand-proof baffle hinged at the end of the hinge rod, and multiple evenly distributed radial grooves formed on the outer wall of the seat pad, the sand-proof baffle sliding inside the radial grooves, and a breaking cone tooth provided on the outer wall of the sand-proof baffle. The upper sand-proof component disposed on the seat pad has the same structure as the lower sand-proof component on the well washing seat.

[0010] Preferably, an upper fixing pin and a lower fixing pin are provided on the outer wall of the outer central tube. The end of the outer central tube is an inlet, which is tapered. An outlet is provided on the outer surface of the outer central tube. The upper fixing pin abuts against the sliding seat in the upper sandproof assembly, and the lower fixing pin abuts against the sliding seat in the lower sandproof assembly.

[0011] Preferably, the lower fixed piston is located inside the lower hydraulic cylinder, the bottom end of the lower hydraulic cylinder is engaged with the bottom connector, the top of the lower hydraulic cylinder is sealed to the outer wall of the inner central tube, another set of pressure ports is located between the lower fixed piston and the top of the lower hydraulic cylinder, the lower fixed piston is threaded to the outer wall of the inner central tube, the lower snap ring seat is installed inside the lower hydraulic cylinder, the inner wall of the lower hydraulic cylinder is provided with the same ratchet teeth as the inside of the locking tube, the lower snap ring seat has the same structure as the upper snap ring seat, and a release shear pin is provided between the lower snap ring seat and the outer wall of the inner central tube.

[0012] Preferably, the bottom of the well-washing seat is engaged with the top of the lower hydraulic cylinder. The backwashing assembly includes a well-washing valve and abutment spring. The well-washing seat has an installation countersunk hole inside. One end of the abutment spring is located inside the installation countersunk hole, and the other end abuts against the tail of the well-washing valve. The end of the well-washing valve is tapered, and a sealing gasket is provided on the outer wall of the well-washing valve.

[0013] Preferably, the well washing base has a liquid inlet and the seat pad has a liquid outlet. The liquid inlet is connected to the inlet of the outer central pipe and the liquid outlet is connected to the outlet of the outer central pipe.

[0014] Preferably, two sets of annular grooves are formed on the surface of the inner central tube, and the outer central tube is sleeved on the outside of the inner central tube, with a gap between the inner wall of the outer central tube and the outer wall of the inner central tube. The annular groove near the inlet of the outer central tube is provided with multiple layers of coarse crushing tooth rings, and the annular groove near the outlet of the outer central tube is provided with multiple layers of fine crushing tooth rings. The outer wall diameter of the outer central tube between the two sets of annular grooves is smaller than the maximum diameter of the inner central tube.

[0015] Beneficial effects Compared with the prior art, the present invention provides a water-blocking packer structure, which has the following beneficial effects: 1. The structure of this water-blocking seal device, through the setting of the upper extrusion mechanism and the lower extrusion mechanism, can simultaneously apply pressure to both ends of the rubber cylinder during use, so that the rubber cylinder expands and deforms evenly, improves the sealing effect, and can extend the service life of the rubber cylinder.

[0016] 2. The structure of this water-blocking packer, through the setting of the upper and lower sand-blocking components, allows the sand-blocking baffle to slide out from the radial groove during the setting process due to the movement of the seat and the well-washing seat, thus shielding the rubber sleeve, reducing the impact and friction of mud and sand on the rubber sleeve, and further improving the service life of the rubber sleeve and the sealing performance of the setting.

[0017] 3. The structure of this water-blocking packer, through the setting of crushing cone teeth, coarse crushing tooth rings and fine crushing tooth rings on the outside of the sand-proof baffle, can impact and crush large particles of mud and sand during the backwashing process, preventing the channel from being blocked during the backwashing. Furthermore, the setting of crushing teeth of different specifications can make the particle size of mud and sand gradually decrease as it passes through the backwashing channel, reducing the wear on the inner wall of the outer central pipe and the outer wall of the inner central pipe, and further improving the service life of the water-blocking packer. Attached Figure Description

[0018] Figure 1 This is a schematic diagram of the overall structure of the present invention; Figure 2 This is a schematic diagram of the overall cross-sectional structure of the present invention; Figure 3 This is a schematic diagram of the assembly structure of the inner central tube and the outer central tube of the present invention; Figure 4 This is a partial cross-sectional structural diagram of the inner central tube and the outer central tube of the present invention; Figure 5 This is a schematic diagram of the outer central tube structure of the present invention; Figure 6 This is a schematic diagram of the inner central tube structure of the present invention; Figure 7 This is a partial cross-sectional structural diagram of the lower extrusion mechanism of the present invention; Figure 8 This is a partial cross-sectional view of the upper extrusion mechanism of the present invention; Figure 9 This is a schematic diagram of the seat cushion structure of the present invention.

[0019] In the diagram: 1. Inner central tube; 101. Pressurization port; 2. Top connector; 3. Adjusting ring; 4. Top seat; 5. Upper hydraulic cylinder; 6. Upper fixed piston; 7. Locking tube; 71. Racket tooth; 8. Upper circlip seat; 81. Circlip; 9. Circlip bearing sleeve; 10. Seat pad; 11. Seat seal shear pin; 1101. Axial groove; 1102. Sliding seat; 1103. Hinge rod; 1104. Radial groove; 1105. Sand baffle; 1106. Crushing cone tooth; 12. Outer center tube; 1201. Upper fixed top pin; 1202. Lower fixed top pin; 1203. Inlet; 1204. Outlet; 13. Rubber sleeve; 14. Spacer ring; 15. Bottom connector; 16. Lower hydraulic cylinder; 17. Lower fixed piston; 18. Lower snap ring seat; 19. Unsealing shear pin; 20. Well washing seat; 21. Well washing valve; 22. Abutment spring; 23. Liquid inlet; 24. Liquid outlet; 25. Coarse crushing toothed ring; 26. Fine crushing toothed ring. Detailed Implementation

[0020] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0021] Example 1 For one embodiment of the present invention, please refer to [link / reference]. Figures 1 to 9 The water-blocking packer of this application has a coaxial sleeve structure. The core components are assembled sequentially along the inner central tube 1. The specific structure and assembly relationship are as follows: Main support structure: The inner central tube 1 is the core support component of the tool. The top end is connected to the top connector 2 by a thread, and the bottom end is connected to the bottom connector 15 by a thread. The outer central tube 12 is coaxially sleeved outside the inner central tube 1, forming an annular flow channel between the inner central tube 1 and the inner central tube 1 for the flow of backwashing fluid. Top limiting assembly: Composed of adjusting ring 3 and top seat 4. The inner wall of top seat 4 is threaded to the outer wall of the top end of inner center tube 1, and the outer wall of top seat 4 is threaded to adjusting ring 3. The bottom of top seat 4 is inserted into the top of upper hydraulic cylinder 5 to limit the initial position of upper hydraulic cylinder 5. At the same time, the preload of upper hydraulic cylinder can be adjusted by adjusting ring 3. The upper extrusion mechanism is coaxially sleeved outside the inner central tube 1 and located below the top limiting component. It includes an upper hydraulic cylinder 5, an upper fixed piston 6, a locking tube 7, an upper snap ring seat 8, a snap ring bearing sleeve 9, and a seat pad 10. The upper fixed piston 6 is threaded to the outer wall of the inner central tube 1 and fixed inside the upper hydraulic cylinder 5. The inner wall of the locking tube 7 is provided with multiple layers of annular ratchet teeth 71. The upper snap ring seat 8 is installed inside the locking tube 7, and the snap ring 81 on it is unidirectionally engaged with the ratchet teeth 71. The snap ring bearing sleeve 9 is threaded to the top end of the outer central tube 12, and the seat pad 10 is connected to the snap ring bearing sleeve 9 through a seat sealing shear pin 11. Multiple rubber cylinders 13 are coaxially sleeved outside the outer central tube 12. A spacer ring 14 is provided between adjacent rubber cylinders 13 to disperse the compressive stress of the rubber cylinders and prevent the rubber cylinders from being squeezed and damaged. The top of the rubber cylinder abuts against the seat pad 10 and the bottom abuts against the well washing seat 20 of the lower extrusion mechanism. Expansion sealing is achieved through upper and lower extrusion. The lower extrusion mechanism is coaxially sleeved outside the inner central tube 1, located below the rubber sleeve 13, and includes a lower hydraulic cylinder 16, a lower fixed piston 17, a lower snap ring seat 18, a well-washing seat 20, and a lower sand-prevention assembly. The lower fixed piston 17 is threaded to the outer wall of the inner central tube 1 and fixed inside the lower hydraulic cylinder 16; the inner wall of the lower hydraulic cylinder 16 is provided with ratchet teeth 71 identical to those of the locking tube 7; the lower snap ring seat 18 is installed inside the lower hydraulic cylinder 16, and a release shear pin 19 is provided between it and the inner central tube 1; the well-washing seat 20 is engaged with the top of the lower hydraulic cylinder 16, and a backwashing assembly (well-washing valve 21, abutment spring 22) is installed inside it. Backwashing fluid flow channel: The well seat 20 has an inlet 23 and the seat pad 10 has a outlet 24. The inlet 23 is connected to the conical inlet 1203 of the outer central tube 12, and the outlet 24 is connected to the outlet 1204 of the outer central tube 12, forming a complete backwashing fluid flow channel.

[0022] The working process of this water-blocking seal device consists of the following steps: Downhole Procedure: After the packer is assembled, it is connected to the tubing string via the top connector 2 and lowered to the designed water-blocking layer of the well. During the downhole procedure, the sealing shear pin 11 and the releasing shear pin 19 remain intact, the upper and lower hydraulic cylinders are in their initial positions, the rubber sleeve 13 is in a free state, the sand baffle 1105 retracts into the seat pad 10 and the well-washing seat 20, the well-washing valve 21 closes under the action of the abutment spring 22, and the overall outer diameter of the tool is smaller than the inner diameter of the wellbore, allowing it to be successfully lowered to the target position.

[0023] Setting process: After the packer is lowered to the designed level, pressurized fluid is injected into the oil pipe. The pressurized fluid enters the upper hydraulic cylinder 5 (between the upper fixed piston 6 and the upper hydraulic cylinder 5) and the lower hydraulic cylinder 16 (between the lower fixed piston 17 and the lower hydraulic cylinder 16) through the two sets of pressurization ports 101 of the inner central tube 1. The action of the upper hydraulic cylinder 5 is as follows: when the internal pressure of the upper hydraulic cylinder 5 is too high and reaches the shearing pressure of the seat seal shear pin 11, the seat seal shear pin 11 is cut off. At this time, the pressure fluid pushes the upper hydraulic cylinder 5 to move downward along the inner central tube 1. The top seat 4 limits the top of the upper hydraulic cylinder. The upper hydraulic cylinder drives the locking tube 7 to move downward. The ratchet 71 on the inner wall of the locking tube 7 is engaged with the snap ring 81 of the upper snap ring seat 8 in one direction. When the locking tube 7 moves downward, it drives the upper snap ring seat 8, snap ring bearing sleeve 9, and seat pad 10 to move downward synchronously. The bottom end of the seat pad 10 presses the top of the rubber cylinder 13 downward. Action of the lower hydraulic cylinder 16: The pressure fluid pushes the lower hydraulic cylinder 16 to move upward along the inner central tube 1. The lower hydraulic cylinder 16 drives the well washing seat 20 to move upward, and the top of the well washing seat 20 presses the bottom of the rubber cylinder 13 upward. The expansion seal of the rubber sleeve 13: The upper and lower hydraulic cylinders squeeze the rubber sleeve 13 in both directions. Under the limiting action of the spacer ring 14, the rubber sleeve 13 expands radially evenly and fits tightly against the inner wall of the wellbore, thereby achieving the sealing of the oil casing annulus and completing the setting seal. During the downward movement of the locking tube 7 and the upward movement of the lower hydraulic cylinder 16, the snap ring 81 of the upper snap ring seat 8 and the ratchet 71 of the locking tube 7, and the snap ring 81 in the lower snap ring seat 18 and the ratchet 71 in the lower hydraulic cylinder 16, always maintain a one-way engagement, restricting the reverse movement of the upper hydraulic cylinder 5 and the lower hydraulic cylinder 16, achieving permanent locking after setting, preventing the rubber sleeve 13 from rebounding, and ensuring the reliability of the seal.

[0024] Backwashing process: When backwashing is required, high-pressure washing fluid is injected into the casing. The pressure of the washing fluid overcomes the elastic force of the abutment spring 22, opens the washing valve 21, and the washing fluid enters the annular flow channel between the inner central tube 1 and the outer central tube 12 through the inlet 23 of the washing seat 20 and the inlet 1203 of the outer central tube 12. After backwashing is completed, the injection of washing fluid is stopped, the washing valve 21 is reset under the action of the abutment spring 22, the washing flow channel is closed, and the sealing state is restored.

[0025] Unsealing process: When the packer needs to be removed, the tubing string is lifted; the tubing string drives the inner central tube 1 upward, and under the action of the friction of the rubber sleeve 13, the inner central tube 1 breaks the unsealing shear pin 19 between the lower snap ring seat 18 and the inner central tube 1, the lower hydraulic cylinder 16 loses its lock, and moves downward under the action of the rebound force of the rubber sleeve 13. The rubber sleeve 13 contracts and separates from the inner wall of the wellbore, completing the unsealing.

[0026] During use, the bidirectional compression of the rubber cylinder 13 ensures uniform force distribution at both ends, improving both the sealing performance and the service life of the rubber cylinder 13. Example 2 As one embodiment of the present invention, please refer to Figure 8 and Figure 9Based on Embodiment 1, this application further includes an upper sand-proof component provided at the end of the seat cushion 10 and a lower sand-proof component provided at the end of the well washing seat 20. The upper sand control component includes an axial groove 1101 provided at the end of the seat pad 10, a sliding seat 1102 slidably disposed inside the axial groove 1101, a hinge rod 1103 installed on the inner wall of the sliding seat 1102, and a sand control baffle 1105 hinged at the end of the hinge rod 1103. Multiple evenly distributed radial grooves 1104 are provided on the outer wall of the seat pad 10, and the sand control baffle 1105 slides inside the radial grooves 1104. The outer wall of the sand control baffle 1105 is provided with breaking cone teeth 1106. The upper sand control component disposed on the seat pad 10 has the same structure as the lower sand control component disposed on the well washing seat 20.

[0027] In operation: When the seat 10 and the well seat 20 move downward and upward respectively with the upper and lower extrusion mechanisms, the upper fixed top pin 1201 and the lower fixed top pin 1202 located on the outer wall of the outer central tube 12 push the sliding seat 1102 of the upper and lower sand prevention components to move along the axial sliding groove 1101. The sliding seat 1102 pushes the sand prevention baffle 1105 to extend outward along the radial sliding groove 1104 through the hinge rod 1103, forming an annular sand prevention barrier to block the mud and sand from scouring the rubber cylinder 13 and protect the rubber cylinder 13. In addition, the crushing cone teeth 1106 on the outer wall of the sand prevention baffle 1105 can crush large sand particles to prevent mud and sand particles from getting stuck in the tool parts.

[0028] Example 3 As one embodiment of the present invention, please refer to 3 to Figure 6 Based on Embodiment 1, this application further includes two sets of annular grooves on the surface of the inner central tube 1, and the outer central tube 12 is sleeved on the outside of the inner central tube 1, with a gap between the inner wall of the outer central tube 12 and the outer wall of the inner central tube 1. The annular groove near the inlet 1203 of the outer central tube 12 is provided with multiple layers of coarse crushing tooth rings 25, and the annular groove near the outlet 1204 of the outer central tube 12 is provided with multiple layers of fine crushing tooth rings 26. The outer wall diameter of the outer central tube 12 between the two sets of annular grooves is smaller than the maximum diameter of the inner central tube 1.

[0029] During the well washing process, as the washing fluid flows through the annular flow channel, the coarse crushing tooth ring 25 and fine crushing tooth ring 26 on the outside of the inner central tube 1 perform two-stage crushing of impurities and sand particles in the washing fluid to prevent impurities from clogging the flow channel. The crushed washing fluid enters the interior of the inner central tube 1 through the outlet 1204 of the outer central tube 12 and the drain port 24 of the seat 10, and finally returns to the surface from the oil pipe, completing the backwashing operation and cleaning impurities and sand particles in the wellbore.

[0030] During use, the coarse crushing tooth ring 25 and the fine crushing tooth ring 26 work together to classify and crush impurities in the backwashing fluid, ensuring crushing efficiency while avoiding tooth ring clogging, greatly improving the backwashing effect and extending the tool's service life.

[0031] It should be noted that, in this document, relational terms such as "first" and "second" are used merely to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitations, an element defined by the phrase "comprising one" does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes the element.

[0032] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A water-blocking seal structure, comprising an inner central tube (1), a top limiting assembly, an upper extrusion mechanism, an outer central tube (12), a rubber cylinder (13), a lower extrusion mechanism, and a bottom connector (15), characterized in that: The top limiting component is installed at the top of the inner central tube (1), the bottom connector (15) is installed at the bottom of the inner central tube (1), the end of the upper extrusion mechanism abuts against the bottom of the top limiting component, the rubber tube (13) is set outside the outer central tube (12), the bottom of the upper extrusion mechanism abuts against the rubber tube (13), the top of the lower extrusion mechanism abuts against the rubber tube (13), and the top limiting component, the upper extrusion mechanism, the outer central tube (12) and the lower extrusion mechanism are all set outside the inner central tube (1); Two sets of pressurization ports (101) are provided on the inner wall of the inner central tube (1). The upper extrusion mechanism includes an upper hydraulic cylinder (5), an upper fixed piston (6), a locking tube (7), an upper snap ring seat (8), a snap ring bearing sleeve (9), and a seat cushion (10). The end of the seat cushion (10) is provided with an upper sand-proof component. Multiple rubber tubes (13) are provided and are sleeved on the outside of the outer central tube (12). A spacer ring (14) is provided between adjacent rubber tubes (13). The lower extrusion mechanism includes a lower hydraulic cylinder (16), a lower fixed piston (17), a lower snap ring seat (18), a well washing seat (20), and a backwashing assembly. The end of the well washing seat (20) is provided with a lower sand control assembly, and the inside of the well washing seat (20) is provided with a backwashing assembly.

2. The water-blocking seal structure according to claim 1, characterized in that: The top limiting assembly includes a top connector (2), an adjusting ring (3), and a top seat (4). The top connector (2) is threaded to the end of the inner central tube (1). The inner wall of the top connector (2) is threaded to the outer wall of the end of the inner central tube (1). The outer wall of the top connector (2) is threaded to the adjusting ring (3). The top of the top seat (4) abuts against the bottom of the adjusting ring (3). The bottom of the top seat (4) is inserted into the top of the upper hydraulic cylinder (5).

3. The water-blocking seal structure according to claim 1, characterized in that: The upper fixed piston (6) is located inside the upper hydraulic cylinder (5). The upper fixed piston (6) is connected to the outer wall of the inner central tube (1) by a thread. A sealing ring is provided between the bottom end of the upper hydraulic cylinder (5) and the outer wall of the inner central tube (1). One set of pressure ports (101) is located between the bottom of the upper hydraulic cylinder (5) and the upper fixed piston (6).

4. The water-blocking seal structure according to claim 1, characterized in that: The inner wall of the locking tube (7) is provided with several layers of ratchet teeth (71), which are arranged in a ring. The upper snap ring seat (8) is located inside the locking tube (7). Several snap rings (81) are provided on the upper snap ring seat (8). The snap rings (81) and the ratchet teeth (71) are snapped together. One end of the upper snap ring seat (8) is provided with a snap ring support sleeve (9). The end of the outer center tube (12) is provided with an external thread. The end of the snap ring support sleeve (9) is threaded to the end of the outer center tube (12). The snap ring support sleeve (9) is located inside the seat cushion (10). The outer wall of the seat cushion (10) is equipped with a seat sealing scissor (11). The outer wall of the snap ring support sleeve (9) is provided with an annular groove. The end of the seat sealing scissor (11) is inserted into the annular groove of the snap ring support sleeve (9).

5. The water-blocking seal structure according to claim 1, characterized in that: The upper sand control component includes an axial groove (1101) provided at the end of the seat (10), a sliding seat (1102) slidably provided inside the axial groove (1101), a hinge rod (1103) installed on the inner wall of the sliding seat (1102), a sand control baffle (1105) hinged at the end of the hinge rod (1103), a plurality of evenly distributed radial grooves (1104) provided on the outer wall of the seat (10), the sand control baffle (1105) sliding inside the radial grooves (1104), and a breaking cone tooth (1106) provided on the outer wall of the sand control baffle (1105). The upper sand control component provided on the seat (10) has the same structure as the lower sand control component on the well washing seat (20).

6. The water-blocking seal structure according to claim 5, characterized in that: The outer wall of the outer central tube (12) is provided with an upper fixed pin (1201) and a lower fixed pin (1202). The end of the outer central tube (12) is an inlet (1203), which is tapered. An outlet (1204) is provided on the outer surface of the outer central tube (12). The upper fixed pin (1201) abuts against the sliding seat (1102) in the upper sandproof assembly, and the lower fixed pin (1202) abuts against the sliding seat (1102) in the lower sandproof assembly.

7. The water-blocking seal structure according to claim 1, characterized in that: The lower fixed piston (17) is located inside the lower hydraulic cylinder (16). The bottom end of the lower hydraulic cylinder (16) is engaged with the bottom connector (15). The top of the lower hydraulic cylinder (16) is sealed to the outer wall of the inner central tube (1). Another set of pressure ports (101) is located between the lower fixed piston (17) and the top of the lower hydraulic cylinder (16). The lower fixed piston (17) is threaded to the outer wall of the inner central tube (1). The lower snap ring seat (18) is installed inside the lower hydraulic cylinder (16). The inner wall of the lower hydraulic cylinder (16) is provided with the same ratchet (71) as the inside of the locking tube (7). The lower snap ring seat (18) has the same structure as the upper snap ring seat (8). The lower snap ring seat (18) is provided with a release shear pin (19) between the lower snap ring seat (18) and the outer wall of the inner central tube (1).

8. The water-blocking seal structure according to claim 1, characterized in that: The bottom of the well-washing seat (20) is engaged with the top of the lower hydraulic cylinder (16). The backwashing assembly includes a well-washing valve (21) and a retaining spring (22). The well-washing seat (20) has an installation countersunk hole inside. One end of the retaining spring (22) is located inside the installation countersunk hole, and the other end abuts against the tail of the well-washing valve (21). The end of the well-washing valve (21) is tapered, and a sealing gasket is provided on the outer wall of the well-washing valve (21).

9. The water-blocking seal structure according to claim 6, characterized in that: The well seat (20) is provided with an inlet (23) and the seat cushion (10) is provided with a drain (24). The inlet (23) is connected to the inlet (1203) of the outer central pipe (12) and the drain (24) is connected to the outlet (1204) of the outer central pipe (12).

10. A water-blocking seal structure according to claim 9, characterized in that: Two sets of annular grooves are provided on the surface of the inner central tube (1). The outer central tube (12) is sleeved on the outside of the inner central tube (1), and there is a gap between the inner wall of the outer central tube (12) and the outer wall of the inner central tube (1). The annular groove near the inlet (1203) of the outer central tube (12) is provided with multiple layers of coarse crushing tooth rings (25), and the annular groove near the outlet (1204) of the outer central tube (12) is provided with multiple layers of fine crushing tooth rings (26). The outer wall diameter of the outer central tube (12) between the two sets of annular grooves is smaller than the maximum diameter of the inner central tube (1).

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