Soluble Layered Extrusion Plugging Tool

Abstract

A soluble layered injection plugging tool belongs to the field of oilfield equipment technology. The tool includes a release lock mechanism and an upper sealing assembly connected to the upper central pipe, a lower sealing assembly connected to the lower central pipe, and a one-way valve installed inside the lower central pipe. The release lock mechanism connects the upper connector and the upper central pipe, eliminating the risk of premature release when conventional packers encounter obstruction during well running. The upper and lower sealing assemblies ensure reliable sealing during plugging operations on a specific formation in the oil well. The anti-backflow valve core automatically seals the tubing passage after injection stops due to the spring's rebound force, making the valve core's seal more reliable and preventing the agent from flowing back into the tubing. This ensures sufficient agent remains within the plugging layer, solidifying to achieve the best plugging effect. The development and use of this tool significantly shortens the plugging construction cycle and improves economic efficiency.

Description

Technical Field

[0001] This invention belongs to the field of oilfield equipment technology, and specifically relates to a soluble stratified injection and plugging tool. Background Technology

[0002] After years of high-speed, high-intensity water injection development, the overall water cut of the oilfield has increased dramatically. Simultaneously, well damage issues such as casing leakage and leaks have also risen sharply, leading to a continuous decrease in water-drive controlled reserves. The oilfield has entered a period of extremely high water cut development, severely impacting normal development. Therefore, on-site work is underway to locate and plug water in oil and water wells, conduct well condition surveys, and perform plugging, sealing, and leakage repair operations on affected wells to ensure a good level of oilfield development.

[0003] Commonly used techniques in operations such as squeezing, plugging, and sealing leaks include casing push method, bare tubing top method, and packer squeezing method. These methods have a common feature: after squeezing and plugging, drilling and plugging are required before production can begin. The construction period for drilling and plugging is relatively long, usually a week or even longer, which will affect the normal production of oil wells and reduce production efficiency. Summary of the Invention

[0004] To address the shortcomings of existing technologies, the purpose of this invention is to provide a soluble, layered extrusion sealing tool.

[0005] The technical solution adopted in this invention is: a soluble layered extrusion sealing tool, the key technical point of which is that it includes a release locking mechanism, wherein the release locking mechanism includes an upper central tube, a protective piston is inserted into the upper central tube, the protective piston is positioned by the head of a protective shear pin fixed on the central tube and inserted into a groove on its surface, an upper connector is inserted into the upper central tube, and the release piston is sleeved on the upper connector and fixed by the release piston shear pin. The release piston contacts the outer arc surface of the locking block inserted into the square hole of the upper central tube; the threaded ring is threadedly connected to the upper connector, and the upper outer sleeve is simultaneously fitted over the upper central tube, the release piston, and the threaded ring. The upper outer sleeve is fixed by inserting the shear head of the upper setting shear pin into the groove of the threaded ring; the upper locking ring is fitted over the upper central tube; the upper retaining ring, which can be radially retracted, is fitted over the groove on the upper locking ring, and the upper retaining ring is fitted over the groove on the outside of the upper central tube to fix the upper locking ring; an upper sealing assembly is also fitted over the upper central tube, which, after compression and expansion, fills the annular space between the casing and the tubing and seals the annular space; a connecting short section connects the upper lower connector and the lower upper connector, and the lower central tube is threadedly connected to and fixed to the lower upper connector. The injection piston is fitted over the lower... Outside the central tube, an injection piston shear pin is threaded onto the injection piston, with the pin head inserted into a groove on the lower central tube, simultaneously fixing the injection piston in its installation position. A lower locking ring is fitted over the lower central tube, and a lower retaining ring with a radially retractable opening is fitted into a groove on the lower locking ring, used to secure the lower retaining ring to the groove outside the lower central tube. The lower outer sleeve is fitted over the injection piston and the lower upper connector, with a lower setting shear pin, its pin head inserted into the groove of the upper connector, threaded onto the lower outer sleeve to position it. A lower sealing assembly is also fitted over the lower central tube, which, after compression and expansion, fills the annular space between the casing and the tubing, sealing the annular space. A one-way valve for the passage of the agent is also provided inside the lower central tube.

[0006] The above solution also includes a protective piston retaining ring fitted inside the groove of the protective piston.

[0007] The above scheme also includes a steel ball inserted by the upper connector, which presses against the upper part of the protective piston to cut the protective shear pin.

[0008] In the above scheme, the upper sealing assembly consists of an upper gauge ring, an upper central tube, an upper lower connector, an upper side rubber sleeve, and an upper middle rubber sleeve. The upper gauge ring is fitted over the upper central tube and is fixedly connected to the upper outer sleeve by threads. The upper side rubber sleeve and the upper middle rubber sleeve are both fitted over the upper central tube, and the upper lower connector is fixedly connected to the upper central tube by threads.

[0009] In the above scheme, the lower sealing assembly consists of a lower gauge ring, a central tube, a lower plug, a lower outer rubber sleeve, and a lower middle rubber sleeve. The lower gauge ring is fitted over the lower central tube and fixed to the lower outer sleeve by a threaded connection. The lower outer rubber sleeve and the lower middle rubber sleeve are fitted over the lower central tube.

[0010] In the above scheme, the one-way valve includes an anti-backflow valve core with an inserted valve core spring, the valve core spring is sleeved on the lower plug, and the front end of the anti-backflow valve core contacts the inside of the lower central tube under the pressure of the valve core spring.

[0011] The beneficial effects of this invention are as follows: This soluble layered injection plugging tool includes a release lock mechanism and an upper sealing assembly connected to the upper central tube, a lower sealing assembly connected to the lower central tube, and a one-way valve installed inside the lower central tube. The release lock mechanism connects the upper connector and the upper central tube, eliminating the risk of premature release when conventional packers encounter obstruction during well running. The upper and lower sealing assemblies ensure reliable sealing for plugging operations on a specific formation in the oil well. The anti-backflow valve core automatically seals the tubing passage after injection stops due to the spring's rebound force, making the valve core's seal more reliable and preventing the agent from flowing back into the tubing. This ensures sufficient agent remains within the plugging layer, solidifying to achieve the best plugging effect. The development and utilization of this tool significantly shortens the plugging construction cycle and improves economic efficiency. Attached Figure Description

[0012] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0013] Figure 1 This is a diagram showing the usage status of the soluble layered extrusion sealing tool in an embodiment of the present invention;

[0014] Figure 2 This is a schematic diagram of the soluble layered extrusion sealing tool in an embodiment of the present invention;

[0015] Figure 3 for Figure 2 A schematic diagram of direction AA;

[0016] Figure 4 This is a schematic diagram of the upper connector structure in an embodiment of the present invention;

[0017] Figure 5 This is a schematic diagram of the upper central tube structure in an embodiment of the present invention;

[0018] Figure 6 This is a schematic diagram of the locking block structure in an embodiment of the present invention;

[0019] Figure 7 This is a schematic diagram of the upper retaining ring structure in an embodiment of the present invention;

[0020] Figure 8 for Figure 2 A magnified view of a portion of the image;

[0021] Figure 9 for Figure 3 A magnified view of a portion of the image;

[0022] The numbers in the diagram are explained as follows: 1. Upper connector, 2. Threaded ring, 3. Upper setting shear pin, 4. Upper center tube, 5. Protective piston, 6. 7. Locking block, 8. Protective shear pin, 9. Release piston, 10. Protective piston circlip, 11. Upper outer sleeve, 12. Upper locking ring, 13. Upper retaining ring, 14. Upper gauge ring, 15. Upper side rubber sleeve, 16. Upper middle rubber sleeve, 17. Upper lower connector, 18. Connecting short section, 19. Lower upper connector, 20. Lower center tube, 21. Lower setting shear pin, 22. Lower outer sleeve, 23. Injection piston, 24. Injection piston shear pin, 25. Anti-backflow valve core, 26. Lower locking ring, 27. Lower circlip, 28. Lower retaining ring, 29. Lower gauge ring, 30. Valve core spring, 31. Lower side rubber sleeve, 32. Lower middle rubber sleeve, 33. Lower plug, 34. Release piston shear pin, 35. Steel ball, 36. Upper sealing assembly, 37. Lower sealing assembly, 38. Tubing, 39. Casing, 40. Artificial bottom hole. Detailed Implementation

[0023] To make the above-mentioned objects, features and advantages of the present invention more apparent and understandable, the following description is provided in conjunction with the accompanying drawings. Figures 1-9 The present invention will be further described in detail below with reference to specific embodiments.

[0024] The soluble layered extrusion sealing tool used in this embodiment includes a central tube 4 and a protective piston 5 inserted into the upper central tube 4. A protective piston retaining ring 9 is fitted into the upper groove of the protective piston 5. Protective shear pins 7 are threaded onto the central tube 4, with the pin heads inserted into the upper groove of the protective piston 5 to position the piston. The upper connector 1 is inserted into the outside of the upper central tube 4, and the locking block 6 is inserted into the square hole N on the upper central tube 4. Figure 5 Point L in locking block 6 contacts point K in upper central tube 4. Figure 6 The release piston 8 is fitted over the upper connector 1 and simultaneously contacts the outer arc surface of the locking block 6; the release piston shear pin 3 is fixed to the release piston 8 by threads, with the pin head inserted into position M of the upper connector 1, see... Figure 5 In this embodiment, the upper connector 1 (e.g.) Figure 5 (as shown), release piston 8, upper center tube 4 (as shown) Figure 6 As shown), lock block 6 (as shown) Figure 7(As shown), the protective piston 5, protective shear pin 7, and release piston shear pin 34 constitute a release lock mechanism, connecting the upper connector 1 and the upper central tube 4 together, allowing for smooth downhole operation. The protective piston isolates the internal and external pressures, preventing the release piston 8 from shearing off during downhole operation or packer release due to high pressure inside the tubing, which could cause premature separation of the upper connector 1 and upper central tube 4, rendering the tool ineffective. Only when the steel ball 35 is inserted and reaches point A on the upper part of the protective piston 5, and pressure is applied to shear the protective shear pin 7, will the protective piston 5 move downwards, exposing the hole at point B inside the tubing. (See...) Figure 2 At this point, the pressure inside the oil pipe is transmitted to the release piston 8 through this hole, cutting the release piston shear pin 34 and causing the release piston 8 to move upward. At this time, the external restraint on the locking block 6 is removed. Lifting the upper connector 1 will generate a radial force at the point of contact between the locking block 6 and the upper central tube 4, causing the locking block to move outward to the space Q on the release piston. (See...) Figure 2 This causes the upper connector 1 to lose connection with the upper central tube 4 and separate, thus achieving the purpose of letting go. At this time, the upper tube column connected to the upper connector 1 can be easily removed.

[0025] In this embodiment, the threaded ring 2 is threadedly connected and fixed to the upper connector 1. The upper outer sleeve 10 is simultaneously fitted over the upper central tube 4, the release piston 8, and the threaded ring 2. The upper outer sleeve 10 is fixed by inserting the upper shear head of the upper sealing shear pin 3 into the groove of the threaded ring 2. The upper locking ring 11 is fitted over the upper central tube 4; the upper retaining ring 12 is fitted into the groove on the upper locking ring 11. Because it has an opening, it can contract radially, such as... Figure 8 The opening above P is shown. The upper retaining ring 13 is fitted into the groove outside the upper central tube 4 to fix the position of the upper locking ring 11. The upper gauge ring 14 is fitted onto the outside of the upper central tube 4 and is threadedly connected and fixed to the upper outer sleeve 10. The upper rubber sleeve 15 and the upper middle rubber sleeve 16 are both fitted onto the upper central tube 4. The upper lower connector 17 is threadedly connected and fixed to the upper central tube 4, and the upper lower connector 17 has a channel D inside. Here, the upper gauge ring 14, the upper central tube 4, the upper lower connector 17, the upper rubber sleeve 15, and the upper middle rubber sleeve 16 form the upper sealing assembly. When the upper gauge ring 14 moves, it compresses the rubber sleeve, causing the rubber to expand and fill the annular space between the sleeve and the rubber sleeve (see...). Figure 1 (At point R in the middle), it serves a sealing function.

[0026] In this embodiment, the connecting section 18 is connected and fixed to the upper lower connector 19 via threads. The lower upper connector 19 is connected and fixed to the connecting section 18 via threads. The lower central tube 20 is connected and fixed to the lower upper connector 19 via threads, and the lower central tube 20 has a cavity E and a drug channel hole H inside. The injection piston 23 is sleeved on the outside of the lower central tube 20, and the injection piston shear pin 24 is fixed to the injection piston 23 via threads. The pin head is inserted into the groove on the lower central tube 20, which simultaneously fixes the injection piston 23 in the installation position. The lower locking ring 26 is sleeved on the outside of the lower central tube 20, and the lower retaining ring 27 is sleeved in the groove on the lower locking ring 26. Because it has an opening, it can retract radially; the lower retaining ring 28 is sleeved in the groove on the outside of the lower central tube 20 to fix the position of the lower locking ring. The lower outer sleeve 22 is simultaneously fitted over the injection piston 23 and the lower upper connector 19. The lower setting shear pin 21 is fixed to the lower outer sleeve 22 by threads, with the pin head inserted into the groove on the upper connector to position the upper outer sleeve there. The lower gauge ring 29 is fitted over the lower center tube 20 and fixed to the upper outer sleeve by threads. The lower rubber sleeve 31 and the lower middle rubber sleeve 32 are fitted over the lower center tube 20. The lower plug 33 is inserted into the lower center tube 20 and fixed to the lower center tube by threads. Here, the lower gauge ring 29, the center tube 20, the lower plug 33, the lower rubber sleeve 31, and the lower middle rubber sleeve 32 constitute the lower sealing assembly. When the lower gauge ring moves, it compresses the rubber sleeve, causing the rubber to expand and fill the annular space between the sleeve and the rubber sleeve (see...). Figure 1 The R-shaped section in the middle section acts as a seal. The anti-backflow valve core 25 is inserted into the valve core spring 30 fitted onto the lower plug 33. The spring has a certain compression margin, ensuring that after installation, the front end of the anti-backflow valve core 25 contacts the interior F section of the lower central tube 20 (see...). Figure 2 This forms a one-way valve structure. When the agent is injected, the agent can pass through normally because the pressure at the top is greater than the preload of the spring. When the injection pressure disappears, the valve core is pressed against the contact point by the spring's rebound force, thereby preventing the agent at the bottom from flowing back to the top, thus maintaining the quantity of agent in the formation and the sealing quality of the formation.

[0027] The tool in this embodiment features prevention of premature loss of control, reliable sealing, no need for drilling plugs, and prevention of chemical backflow. Its specific working principle is as follows:

[0028] (i) Reliable sealing: When it is necessary to perform plugging operations on a specific formation in an oil well, this tool kit is connected to the lower end of the tubing and lowered to the predetermined depth (see...). Figure 1 After that, the pressure from inside the oil pipe first opens the anti-backflow valve core 25, and then the pressure is passed through... Figure 1 The pressure is transmitted from point R in the middle to the upper part of the lower gauge ring 29, while the pressure is transmitted through... Figure 2The pressure at point T is transmitted to the upper part of the upper guide ring 14. As the pressure increases, it successively cuts the upper setting shear pin 3 and the lower setting shear pin 21, and continues to move, compressing the upper and lower rubber sleeves respectively, until the rubber sleeves expand to the point of contacting the sleeve and can no longer be compressed. During this process, C2 moves to position C1 to bring the two parts into contact (see...). Figure 9 J2 moves to position J1 so that the two pieces make contact (see...) Figure 9 At this point, after the oil pipe pressure is released, due to the special shape (one-sided angle) of the upper and lower retaining springs, the parts at the connection between the upper and lower gauge rings can only slide in one direction. Once in position, they are locked in the current position, while maintaining the compression force of the rubber sleeve to achieve the function of sealing the annular space of the tool and the sleeve (see...). Figure 1 (At point R in the middle). At this point, replace the appropriate reagent in the tubing and continue pressurizing to cut the injection piston shear pin 24 at injection piston 23, causing the injection piston to move upwards until it passes through. Figure 2 The injection is carried out through a hole at point I, allowing the agent to continuously enter the formation that needs to be sealed. The injection can be stopped when the predetermined injection volume is reached.

[0029] (II) Prevention of Chemical Backflow: When the injection dosage reaches the designed injection volume and injection is stopped, the pressure inside the tubing drops, while the pressure inside the formation is higher. Without anti-backflow measures, the uncured chemical will flow back into the tubing, resulting in the actual injection dosage not meeting the standard, thus affecting the sealing quality and reducing construction efficiency. The anti-backflow valve core installed in this tool will automatically seal the tubing channel under the rebound force of the spring after injection stops. At the same time, because the pressure at the bottom of the anti-backflow valve core is greater than the pressure at the top after activation, the seal of the valve core is more reliable, preventing the chemical from flowing back into the tubing. This ensures that sufficient chemical is in the sealing layer, and after curing, it achieves the best sealing effect.

[0030] (III) Preventing Premature Release: The tool design in this embodiment includes a release lock mechanism to prevent premature release, eliminating the potential for premature release when conventional packers encounter obstruction during downhole operation. This release lock consists of an upper connector 1, a release piston 8, an upper central tube 4, a locking block 6, a protective piston 5, a protective shear pin 7, and a release piston shear pin 34. This lock connects the upper connector and the upper central tube, allowing for smooth downhole operation. The protective piston separates the internal pressure from the external pressure, preventing premature separation of the upper connector and upper central tube due to high pressure inside the tubing during downhole operation or packer release, thus preventing tool failure. Only after the steel ball 35 is inserted can pressure be applied to the upper part of the protective piston 5 to shear the protective shear pin 7, after which the protective piston moves downwards to point B (see...). Figure 2The hole is exposed inside the oil pipe. The pressure inside the oil pipe is then transmitted through this hole to the release piston 8, shearing the release piston shear pin 34 and causing the release piston to move upwards. At this point, the external restraint on the locking block 6 is removed. Lifting the upper connector 1 will generate a radial force at the point of contact between the locking block and the upper central tube 4 (where the conical surface is in contact), causing the locking block to move outwards to the space Q on the release piston (see...). Figure 2 This causes the upper connector to lose connection with the upper central tube, thus achieving the purpose of letting go. At this time, the upper pipe column connected to the upper connector can be easily removed.

[0031] (iv) No need for drilling plugs: The parts of this tool are made of an aluminum-magnesium alloy material that can automatically dissolve after 48 hours. Therefore, after the injection is completed, there is no need to perform the drilling plug process. It can be directly put into production, which greatly shortens the construction cycle and improves economic benefits.

[0032] The above description is merely a specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in the present invention should be included within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be determined by the scope of the claims.

Claims

1. A soluble, layered extrusion sealing tool, characterized in that... The system includes a release lock mechanism, which comprises an upper central tube. A protective piston is inserted into the upper central tube and positioned by the head of a protective shear pin fixed to the central tube and inserted into a groove on its surface. An upper connector is inserted into the upper central tube, and the release piston is fitted over the upper connector and fixed by the release piston shear pin. The release piston contacts the outer arc surface of the locking block inserted into the square hole of the upper central tube; the threaded ring is threadedly connected to the upper connector, and the upper outer sleeve is simultaneously fitted over the upper central tube, the release piston, and the threaded ring. The upper outer sleeve is fixed by inserting the shear head of the upper setting shear pin into the groove of the threaded ring; the upper locking ring is fitted over the upper central tube; the upper retaining ring, which can be radially retracted, is fitted over the groove on the upper locking ring, and the upper retaining ring is fitted over the groove on the outside of the upper central tube to fix the upper locking ring; an upper sealing assembly is also fitted over the upper central tube, which, after compression and expansion, fills the annular space between the casing and the tubing and seals the annular space; a connecting short section connects the upper lower connector and the lower upper connector, and the lower central tube is threadedly connected to and fixed to the lower upper connector. The injection piston is fitted over the lower... Outside the central tube, an injection piston shear pin is threaded onto the injection piston, with the pin head inserted into a groove on the lower central tube, simultaneously fixing the injection piston in its installation position. A lower locking ring is fitted over the lower central tube, and a lower retaining ring with a radially retractable opening is fitted into a groove on the lower locking ring, used to secure the lower retaining ring to the groove outside the lower central tube. The lower outer sleeve is fitted over the injection piston and the lower upper connector, with a lower setting shear pin, its pin head inserted into the groove of the upper connector, threaded onto the lower outer sleeve to position it. A lower sealing assembly is also fitted over the lower central tube, which, after compression and expansion, fills the annular space between the casing and the tubing, sealing the annular space. A one-way valve for the passage of the agent is also provided inside the lower central tube. It also includes a protective piston retaining ring fitted inside the groove of the protective piston; the one-way valve includes an anti-backflow valve core into which a valve core spring is inserted, the valve core spring is fitted on the lower plug, and the front end of the anti-backflow valve core contacts the inside of the lower central tube under the pressure of the valve core spring.

2. The soluble layered extrusion sealing tool as described in claim 1, characterized in that... It also includes a steel ball inserted by the upper connector, which presses against the upper part of the protective piston to cut the protective shear pin.

3. The soluble layered extrusion sealing tool as described in claim 1, characterized in that... The upper sealing assembly consists of an upper gauge ring, an upper central tube, an upper lower connector, an upper outer rubber sleeve, and an upper middle rubber sleeve. The upper gauge ring is fitted over the upper central tube and is fixedly connected to the upper outer sleeve by threads. The upper outer rubber sleeve and the upper middle rubber sleeve are both fitted over the upper central tube, and the upper lower connector is fixedly connected to the upper central tube by threads.

4. The soluble layered extrusion sealing tool as described in claim 1, characterized in that... The lower sealing assembly consists of a lower gauge ring, a central tube, a lower plug, a lower outer rubber sleeve, and a lower middle rubber sleeve. The lower gauge ring is fitted over the lower central tube and fixed to the lower outer sleeve by a threaded connection. The lower outer rubber sleeve and the lower middle rubber sleeve are fitted over the lower central tube.

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