A tailpipe cementing annulus pressure-reducing tool and its application method

Abstract

This invention discloses a tailpipe cementing annulus pressure-holding tool and its usage method, belonging to the field of tailpipe cementing technology. The tailpipe cementing annulus pressure-holding tool includes: an upper connector, a valve control unit, a valve plate, a valve seat, and a lower connector; the upper connector and the lower connector are fixedly connected; the valve control unit is slidably disposed inside the upper connector and the lower connector, and the valve control unit abuts against the upper connector and the lower connector respectively; one end of the valve control unit abuts against one side wall of the valve plate; the valve plate is rotatably connected to the valve seat; the valve seat is sleeved inside the lower connector, and the outer wall of the valve seat abuts against the inner wall of the lower connector; the valve seat is tubular, with two V-shaped grooves symmetrical about the center of the valve seat on its side wall. The tailpipe cementing annulus pressure-holding tool of this invention has a simple structure, reliable function, and is applicable to tailpipe cementing operations of most casing types, effectively improving cementing quality.

Description

Technical Field

[0001] This invention belongs to the field of tailpipe cementing technology, and specifically relates to a tailpipe cementing annulus pressure-blocking tool and its usage method. Background Technology

[0002] Tail-end cementing technology is a specialized operation characterized by high technical difficulty, complex construction, high operational risks, and stringent quality requirements. With the continuous development of the petroleum industry, tail-end cementing technology can significantly reduce the number of casing pipes used, thereby substantially lowering casing costs, and its advantage of reducing the load on the casing string at the wellhead is becoming increasingly prominent. Tail-end cementing technology can reduce cementing costs and effectively shorten drilling cycles, bringing significant economic benefits and effectively improving drilling conditions. Moreover, tail-end cementing technology is particularly suitable for deep wells and wells encountering complex formations, and is a conventional process. However, in tail-end cementing, because the center pipe needs to be pulled out after cementing, a pressure difference cannot be formed between the annulus and the casing string during wellhead pressurization. This results in poor annular pressure buildup, failing to achieve the purpose of prestressed cementing, and consequently leading to problems such as oil, gas, and water channeling, as well as micro-cracks in the cement annulus.

[0003] Currently, using a special tailpipe hanger is one of the main methods to solve the problem of poor annular pressure build-up in tailpipe cementing. However, the use of a special tailpipe hanger has a large limitation on the selection of wellhead type (tool type), and is only applicable to a few wells that meet the conditions, and the cost is high.

[0004] Chinese patent (publication number CN114922579B) discloses a high-pressure sealing gas-tight tailpipe hanger with embedded slips, including a tailpipe, a mounting assembly, a pressure-holding assembly, a displacement assembly, and a ground receiver. The tailpipe serves as the outer shell of the hanger, with slips embedded in its outer surface. The threaded connection at the upper end of the tailpipe is a tenon-and-mortise structure, comprising a platform and a cuboid. The cuboid is placed flat on the platform, and its outer surface near the return cylinder is flush with the inner surface of the tailpipe. The mounting assembly, located inside and connected to the tailpipe, includes a hydraulic cylinder and a hydraulic cylinder activation device. The activation device controls whether the hydraulic cylinder pressure transmission port is open, allowing the hydraulic cylinder to overcome resistance and move upwards by applying pressure. The upward movement of the slips causes them to open circumferentially, allowing the tailpipe to be suspended by gravity on the inner wall of the upper casing. The pressure-holding assembly, connected to the tailpipe and the mounting assembly, includes a ball seat, a pressure-holding ball, a shallow formation profiler, and shear pins. When the pressure-holding ball falls to the ball seat, pressure is applied from the wellhead, creating a pressure difference between the inside and outside of the tailpipe. This pressure difference pushes the hydraulic cylinder upward to shear the shear pins, causing the slips to be mounted. The displacement assembly, also connected to the tailpipe and the mounting assembly, includes a return sleeve and a loosening thread device. The displacement assembly can move the mounting assembly to the designed mounting position. After the mounting assembly mounts the tailpipe, the loosening thread device on the return sleeve loosens the threaded connection at the upper end of the tailpipe. After cement reinforcement of the tailpipe is completed, the displacement assembly pulls part of the mounting assembly and part of the pressure-holding assembly out of the wellhead. Among these measures, the pressure-holding assembly employs a hydraulic cylinder activation device to prevent premature upward movement of the hydraulic cylinder; the displacement assembly uses a loosening thread device that works in conjunction with the ground receiver to avoid a complex reverse-clamping process; the pressure-holding assembly uses an improved ball seat to protect the pressure-holding ball; and the pressure-holding assembly uses a shallow formation profiler to quickly determine the location of sealing failure during the tailpipe setting process. Failures in tailpipe cementing can range from delaying the project schedule to rendering the well unusable, causing significant economic losses. These measures prevent problems during tailpipe setting and displacement assembly reverse-clamping, greatly increasing the success rate of tailpipe cementing.

[0005] While the tailpipe hanger disclosed in the aforementioned Chinese patent can improve the success rate of tailpipe cementing, it still requires operation in wells that meet specific requirements, limiting its applicability. Therefore, there is an urgent need to develop a new tailpipe cementing annulus pressure-blocking tool to solve the aforementioned technical problems. Summary of the Invention

[0006] To address the aforementioned problems, this invention discloses a tailpipe cementing annulus pressure-blocking tool, comprising: an upper connector, a valve control unit, a valve plate, a valve seat, and a lower connector;

[0007] The upper connector and the lower connector are fixedly connected;

[0008] The valve control unit is slidably disposed inside the upper and lower connectors, and the valve control unit abuts against the upper and lower connectors respectively;

[0009] One end of the valve control unit abuts against one side wall of the valve plate;

[0010] The valve plate is rotatably connected to the valve seat;

[0011] The valve seat is sleeved inside the lower connector, and the outer wall of the valve seat abuts against the inner wall of the lower connector;

[0012] The valve seat is tubular, with two V-shaped grooves symmetrical about the center of the valve seat on its side wall.

[0013] Furthermore, the valve control unit includes: an annular piston;

[0014] An annular protrusion is fixedly provided on the outer wall of the annular piston; the outer wall of the annular protrusion is slidably and sealingly connected to the lower connector;

[0015] The outer wall of the top end of the annular piston is slidably and sealingly connected to the upper connector.

[0016] The annular piston has a threaded hole on its sidewall, and the threaded hole is located below the annular protrusion.

[0017] The bottom surface of the annular piston is inclined, and the inclined surface abuts against the side wall of the valve plate.

[0018] Furthermore, the valve control unit also includes: a hollow shear pin;

[0019] The hollow shear pin is disposed in the threaded hole of the annular piston;

[0020] The hollow inner diameter of the hollow shear pin is 2-8mm.

[0021] Furthermore, the valve control unit also includes: a sealing ring;

[0022] One or more parallel annular grooves are formed on the middle part of the inner wall of the lower connector.

[0023] The sealing ring is fixedly installed in the annular groove of the lower connector;

[0024] One or more sealing rings are provided;

[0025] The outer wall of the annular piston is slidably connected to the inner wall of the lower connector via a sealing ring.

[0026] Furthermore, the annular protrusion divides the cavity between the upper connector, lower connector, annular piston, and sealing ring into a first annular cavity and a second annular cavity;

[0027] The working pressure range of the second annular cavity is 20-70 MPa.

[0028] Furthermore, the annular pressure-blocking tool for tailpipe cementing also includes: torsion springs;

[0029] One end of the torsion spring is connected to the valve plate, and the other end of the torsion spring is connected to the valve seat.

[0030] Furthermore, the valve plate is V-shaped overall;

[0031] The valve plate is matched with the V-groove. When the valve plate is closed, it is positioned within the V-groove of the valve seat.

[0032] Furthermore, the included angle of the V-groove is 90°.

[0033] Furthermore, the tailpipe cementing annulus pressure-blocking tool also includes: a sealing gasket;

[0034] The sealing gasket is V-shaped and is disposed in the V-groove of the valve seat.

[0035] This invention also discloses a method for using the above-mentioned tailpipe cementing annulus pressure-blocking tool, comprising the following steps:

[0036] Connect the tailpipe cementing annulus pressure-blocking tool to the cementing casing string, and then perform tailpipe cementing operations; wherein, under the constraint of the annular piston, the valve plate remains in the normally open state;

[0037] After cementing is completed in the tailpipe, a drill pipe rubber plug is pressed in to replace it. The drill pipe rubber plug and the tailpipe rubber plug together cut the hollow shear pin. The drill pipe rubber plug continues to descend until it touches the pressure, and then pressure is pushed into the well. When the pressure in the second annular cavity is greater than the set pressure, the annular piston slides upward.

[0038] When the annular piston slides upward a set distance, it releases the restriction on the valve plate, and the valve plate closes under the action of the closing torque of the torsion spring and its own weight.

[0039] Pressurize the well again, and the valve plate will be tightly closed with the valve seat due to the pressure.

[0040] Compared with the prior art, the embodiments of the present invention have at least the following advantages: The present invention provides a tailpipe cementing annulus pressure-holding tool, mainly used in tailpipe cementing operations, to improve the annulus pressure-holding effect during tailpipe cementing construction, shorten the initial and final setting time of cement slurry, effectively reduce the generation of micro-cracks in the cement annulus, and ultimately improve the efficiency of tailpipe cementing operations and reduce construction risks; The tailpipe cementing annulus pressure-holding tool of the present invention has the advantages of simple structure and reliable function, and can be applied to tailpipe cementing operations of most casings, effectively improving cementing quality; When using the tailpipe cementing annulus pressure-holding tool of the present invention, no special tailpipe hanger is required during tailpipe cementing operations, and it can be directly connected to the casing string, greatly improving versatility and reducing usage costs; When pressurizing after cementing operations are completed, a pressure difference can be formed between the annulus and the casing by closing the valve plate, improving the annulus pressure-holding effect and thus improving cementing quality.

[0041] Other features and advantages of the invention will be set forth in the following description, and will be apparent in part from the description, or may be learned by practicing the invention. The objects and other advantages of the invention can be realized and obtained by means of the structures pointed out in the description and the drawings. Attached Figure Description

[0042] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0043] Figure 1 A schematic diagram of a tailpipe cementing annulus pressure-blocking tool according to an embodiment of the present invention is shown;

[0044] Figure 2 A schematic diagram of the valve plate in the tailpipe cementing annulus pressure-blocking tool according to an embodiment of the present invention is shown;

[0045] Figure 3 A schematic diagram of the valve seat in the tailpipe cementing annulus pressure-blocking tool according to an embodiment of the present invention is shown;

[0046] Figure 4 A flowchart illustrating the method of using a tailpipe cementing annulus pressure-blocking tool according to an embodiment of the present invention is shown.

[0047] Reference numerals: 1. Upper connector; 2. Annular piston; 3. Hollow shear pin; 4. Sealing ring; 5. Valve plate; 6. Torsion spring; 7. Sealing gasket; 8. Valve seat; 9. Lower connector; 10. Annular protrusion. Detailed Implementation

[0048] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, 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, 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.

[0049] Figure 1 A schematic diagram of a tailpipe cementing annulus pressure-blocking tool according to an embodiment of the present invention is shown. Figure 1 As shown, the present invention proposes a tailpipe cementing annulus pressure-blocking tool, comprising: an upper connector 1, a valve control unit, a valve plate 5, a valve seat 8, and a lower connector 9;

[0050] The upper connector 1 and the lower connector 9 are fixedly connected;

[0051] The valve control unit is slidably disposed inside the upper connector 1 and the lower connector 9, and the valve control unit abuts against the upper connector 1 and the lower connector 9 respectively;

[0052] One end of the valve control unit abuts against one side wall of the valve plate 5;

[0053] The valve plate 5 is rotatably connected to the valve seat 8; for example, the valve plate 5 and the valve seat 8 are rotatably connected by bolts.

[0054] The valve seat 8 is sleeved inside the lower connector 9, and the outer wall of the valve seat 8 abuts against the inner wall of the lower connector 9.

[0055] The valve seat 8 is tubular, and two V-shaped grooves symmetrical about the center of the valve seat 8 are formed on the side wall of the valve seat 8. It should be noted that the two V-shaped grooves are identical.

[0056] Upper connector 1 is used for fixed connection with the cementing casing string, and the tailpipe cementing annulus pressure-reducing tool is connected to the cementing casing string;

[0057] The valve control unit is used to control the opening or closing state of the valve plate 5, and closes the valve plate 5 according to actual needs;

[0058] Valve plate 5 is used to close the cementing casing string. The upper and lower spaces of valve plate 5 are divided to ensure airtightness.

[0059] The valve seat 8 is used to support the valve plate 5. When the valve plate 5 is closed, it fits tightly against the valve plate 5 to ensure airtightness.

[0060] The lower connector 9 is used for fixed connection with the cementing casing string, and the tailpipe cementing annulus pressure-reducing tool is connected to the cementing casing string.

[0061] The valve plate 5 is made of glass or special metal. When normal well completion operations are required, the valve plate 5 can be drilled through by lowering the drill bit, or the valve plate 5 can be broken by pressurizing the well.

[0062] The upper connector 1, valve seat 8, and lower connector 9 are made of high-strength, high-toughness, corrosion-resistant, and high-temperature-resistant alloy steel.

[0063] This invention provides a tailpipe cementing annulus pressure-holding tool, mainly used in tailpipe cementing operations. It enhances the annulus pressure-holding effect during tailpipe cementing construction, shortens the initial and final setting time of cement slurry, effectively reduces the formation of micro-cracks in the cement annulus, and ultimately improves tailpipe cementing operation efficiency and reduces construction risks. This tailpipe cementing annulus pressure-holding tool has the advantages of simple structure and reliable function, and can be applied to tailpipe cementing operations for most casings, effectively improving cementing quality. Furthermore, this tailpipe cementing annulus pressure-holding tool, when pressurizing after cementing operations are completed, creates a pressure difference between the annulus and the casing by closing valve plate 5, improving the annulus pressure-holding effect and thus enhancing cementing quality.

[0064] In some embodiments, the upper connector 1 has an internal sleeve thread at its top for connection with the sleeve string, and a connecting thread on its bottom outer wall for connection with the lower connector 9; the lower connector 9 has a connecting thread on its top inner wall and an external sleeve thread on its bottom outer wall for connection with the sleeve string. The upper connector 1 and the lower connector 9 are connected by threads, with the top of the upper connector 1 threaded to the sleeve string and the bottom of the lower connector 9 threaded to the sleeve string. An annular seal is provided at the connection point between the upper connector 1 and the lower connector 9 to ensure a tight seal. The threaded connection between the upper connector 1 and the lower connector 9 provides high connection strength and stability; it also allows for quick assembly and disassembly, facilitating maintenance and component replacement.

[0065] Although the above description exemplifies the threaded connection between the upper connector 1 and the lower connector 9, the present invention is not limited to this. Various fixing connection methods can be employed, such as pin connections, welding connections, and other connection methods, as long as the sealing performance, connection stability, and connection strength between the upper connector 1 and the lower connector 9 are guaranteed. Those skilled in the art can comprehensively consider the connection principle of the present invention and actual conditions, as long as a stable connection between the upper connector 1 and the lower connector 9 can be achieved.

[0066] When using the tailpipe cementing annulus pressure-retaining tool of the present invention, no special tailpipe hanger is required during tailpipe cementing operations. It can be directly connected to the casing string, which greatly improves versatility and reduces usage costs.

[0067] In some embodiments, the valve plate 5 and the valve seat 8 are connected by a hinge. This hinged connection ensures both the ease of opening and closing the valve plate 5 and the stability of the connection between the two.

[0068] In some embodiments, one or more annular grooves are provided on the inner wall of the lower connector 9, and an annular seal is provided in each annular groove, thereby ensuring the sealing between the outer wall of the valve seat 8 and the inner wall of the lower connector 9 and preventing leakage between the valve seat 8 and the lower connector 9.

[0069] In some other design configurations, one or more annular grooves are provided on the outer wall of the valve seat 8, and an annular seal is provided in each annular groove to ensure the sealing between the outer wall of the valve seat 8 and the inner wall of the lower connector 9.

[0070] In some embodiments, two or more tailpipe cementing annulus pressure-blocking tools may be connected in the cementing casing string according to actual operational needs.

[0071] In some embodiments, the lower connector 9 includes a first inner wall and a second inner wall;

[0072] The diameter of the first inner wall is larger than the diameter of the second inner wall, and a step is provided at the connection between the first inner wall and the second inner wall;

[0073] The valve seat 8 is located at the step and is fixedly connected to the lower connector 9.

[0074] In some embodiments, one or more limiting pins are provided on the inner wall of the lower connector 9. The limiting pins are located below the upper connector 1 and above the annular protrusion 10, and abut against the annular protrusion 10 to limit the annular protrusion 10, thereby limiting the annular piston 2.

[0075] When the hollow shear pin 3 is cut, although the pressure in the second annular cavity will increase rapidly, the annular piston 2 cannot be pushed upward under the action of pressure difference due to the presence of the limiting pin. Only when the pressure in the second annular cavity reaches the set pressure will the annular protrusion 10 cut the limiting pin, and the annular piston 2 can be pushed upward under the action of pressure difference, thereby releasing the limit on the valve plate 5 and closing the valve plate 5.

[0076] In some embodiments, the inner diameter of the valve seat 8 is the same as the diameter of the second inner wall of the lower connector 9. When the valve plate 5 is in the open state, it ensures the normal operation of the tailpipe cementing operation and does not obstruct the transported fluid. It also avoids adverse effects on the tailpipe cementing operation process after the tailpipe cementing annulus pressure-blocking tool of the present invention is installed in the cementing casing string.

[0077] In some embodiments, the valve control unit includes: an annular piston 2;

[0078] An annular protrusion 10 is fixedly provided on the outer wall of the annular piston 2; the outer wall of the annular protrusion 10 is slidably and sealingly connected to the inner wall of the lower connector 9; for example, one or more annular grooves are provided on the outer wall of the annular protrusion 10, and an annular seal is provided in each annular groove. The annular seal is used to ensure the sealing between the annular protrusion 10 and the lower connector 9. When the pressure difference between the second annular cavity and the first annular cavity reaches a set value, the annular piston 2 is pushed upward under the action of the pressure difference, thereby releasing the restriction effect on the valve plate 5.

[0079] The outer wall of the top end of the annular piston 2 is slidably and sealingly connected to the upper connector 1.

[0080] One or more threaded holes are provided on the side wall of the annular piston 2, and the threaded holes are located below the annular protrusion 10.

[0081] The bottom surface of the annular piston 2 is inclined, and the inclined surface abuts against the side wall of the valve plate 5.

[0082] For example, both the annular piston 2 and the annular protrusion 10 are made of alloy steel, giving them high strength and high toughness.

[0083] The annular piston 2 is used to limit the valve plate 5, keeping the valve plate 5 in a normally open state. When it is necessary to close the valve plate 5, it can be closed by the valve control unit.

[0084] The annular piston 2 in the tailpipe cementing annulus pressure-blocking tool of the present invention can flexibly control the closing of the valve plate 5. The closing method is simple and practical, ensuring that the valve plate 5 will not fail to close.

[0085] In some embodiments, one or more annular grooves are formed on the outer wall of the top end of the annular piston 2, and an annular seal is provided in each annular groove, thereby ensuring the sealing between the annular piston 2 and the inner wall of the upper connector 1. In other designs, one or more annular grooves can also be provided on the bottom end of the inner wall of the upper connector 1, and an annular seal is provided in each annular groove, which can also ensure the sealed connection between the upper connector 1 and the annular piston 2.

[0086] In some embodiments, an annular groove is formed on the outer wall of the top end of the annular piston 2, and an annular groove is also formed on the bottom end of the inner wall of the upper connector 1. An annular seal is installed in each annular groove, thereby achieving a sealed connection between the annular piston 2 and the upper connector 1. Of course, those skilled in the art can also use other sealing connection methods, as long as a sliding sealed connection between the annular piston 2 and the upper connector 1 can be achieved.

[0087] In some examples, the annular protrusion 10 has a rectangular cross-section, which facilitates the installation of annular seals on the annular protrusion 10 and ensures the airtightness between the first and second annular cavities. In other designs of the annular protrusion 10, the annular protrusion 10 has a rectangular cross-section, and a U-shaped groove is formed on the surface of the annular protrusion 10 that abuts against the lower connector 9, in which a U-shaped seal can be installed.

[0088] In some embodiments, the valve control unit further includes: a hollow shear pin 3;

[0089] The hollow shear pin 3 has external threads on its outer wall;

[0090] The hollow shear pin 3 is disposed in the threaded hole of the annular piston 2, and the hollow shear pin 3 and the annular piston 2 are connected by threads. For example, the hollow shear pin 3 is made of nylon.

[0091] The hollow shear pin 3 has a hollow inner diameter of 2-8mm, which ensures that the pressure can be quickly transmitted to the second annular cavity when it is sheared.

[0092] In other design approaches, the hollow shear pin 3 can be welded to the threaded hole of the annular piston 2.

[0093] For example, such as Figure 1 As shown, there is one hollow shear pin 3.

[0094] The hollow shear pin 3 is used to control whether pressure is applied to the second annular cavity. When it is necessary to push the annular piston 2 upward, the hollow shear pin 3 can be broken, thereby applying pressure to the second annular cavity. Under the pressure difference between the second and first annular cavities, the annular piston 2 is gradually pushed upward. It should be noted that before the hollow shear pin 3 is broken, the second annular cavity and the interior of the annular piston 2 are not connected. Only by breaking the hollow shear pin 3 can the second annular cavity and the annular piston 2 be connected. Using the hollow shear pin 3 to control whether the second annular cavity and the interior of the annular piston 2 are connected is technically mature, simple to operate, and low in cost.

[0095] Although the above description uses a single hollow shear pin 3 as an example, the present invention is not limited thereto. Multiple hollow shear pins 3 can be used, such as two or three. Those skilled in the art can consider various factors based on actual needs, as long as rapid connection between the second annular cavity and the annular piston 2 can be achieved.

[0096] In some embodiments, the valve control unit further includes: a sealing ring 4;

[0097] One or more parallel annular grooves are formed on the middle part of the inner wall of the lower connector 9; for example, such as Figure 1 As shown, an annular groove is provided on the inner wall of the top end of the lower connector 9, and it is located below the annular protrusion 10.

[0098] The sealing ring 4 is fixedly installed in the annular groove of the lower connector 9;

[0099] The sealing ring 4 is provided with one or more; for example, such as Figure 1 As shown, one sealing ring 4 is provided;

[0100] The bottom outer wall of the annular piston 2 is slidably connected to the inner wall of the lower connector 9 through a sealing ring 4.

[0101] The sealing ring 4 is made of rubber and polytetrafluoroethylene, which gives it good chemical corrosion resistance, high temperature resistance, and wear resistance, ensuring sealing performance.

[0102] The sealing ring 4 is used to seal the connection between the lower connector 9 and the annular piston 2, ensuring the sealing of the second annular cavity and preventing leakage.

[0103] Although the above description uses a single sealing ring 4 as an example, the present invention is not limited thereto. Multiple sealing rings 4 can be used, such as two or three. Those skilled in the art can comprehensively consider the sealing principle and actual needs of the present invention, as long as the sealing performance between the annular piston 2 and the lower connector 9 can be guaranteed.

[0104] In some embodiments, the annular protrusion 10 divides the cavity space between the upper connector 1, the lower connector 9, the annular piston 2 and the sealing ring 4 into a first annular cavity and a second annular cavity.

[0105] The working pressure range of the second annular cavity is 20-70 MPa, which ensures that under the action of the pressure difference between the second annular cavity and the first annular cavity, the annular piston 2 is pushed upward, thereby releasing the limiting effect on the valve plate 5 and quickly closing the valve plate 5.

[0106] In some embodiments, when the valve plate 5 is in the open state, the volumes of the first annular cavity and the second annular cavity are set to be equal, which is beneficial for installing the hollow shear pin 3 on the side wall of the second annular cavity.

[0107] In some embodiments, when the valve plate 5 is in the open state, the cementing casing string is in the connected state, and the valve plate 5 will not obstruct the fluid transport, thus ensuring the normal operation of the tailpipe cementing operation.

[0108] In some embodiments, the tailpipe cementing annulus pressure-blocking tool further includes: a torsion spring 6;

[0109] One end of the torsion spring 6 is connected to the valve plate 5, and the other end of the torsion spring 6 is connected to the valve seat 8.

[0110] The torsion spring 6 is made of spring steel, which gives it excellent mechanical properties, high fatigue strength, and excellent anti-relaxation performance.

[0111] The torsion spring 6 is used to quickly close the valve plate 5 after the valve plate 5 is released from its limit, thereby creating a pressure difference between the annulus and the sleeve.

[0112] In the V-type valve, the torsion spring 6 provides a closing force to the valve plate 5. The valve plate 5 remains open under the constraint of the annular piston 2. When the annular piston 2 moves upward, it releases the constraint on the valve plate 5, and the valve plate 5 closes under the action of torsion and its own gravity.

[0113] Figure 2 A schematic diagram of the valve plate in a tailpipe cementing annulus pressure-retaining tool according to an embodiment of the present invention is shown. Figure 2 As shown, in some embodiments, the valve plate 5 is V-shaped with an arc-shaped outer surface. When the valve plate 5 is vertically installed, it fits against the inner wall of the lower connector 9.

[0114] The valve plate 5 is matched with the V-groove. When the valve plate 5 is closed, it is positioned in the V-groove of the valve seat 8.

[0115] The valve plate 5 is designed in a V-shape, which can effectively reduce the space occupied by the valve plate 5, making it easy to be built into the inner wall of the annular pipe string, and at the same time will not hinder the construction operation.

[0116] Figure 3 A schematic diagram of the valve seat in a tailpipe cementing annulus pressure-retaining tool according to an embodiment of the present invention is shown. Figure 3 As shown, in some embodiments, the included angle of the V-groove is 90°, which can better fit and seal.

[0117] In some embodiments, the tailpipe cementing annulus pressure-blocking tool further includes: a sealing gasket 7;

[0118] The sealing gasket 7 is V-shaped and is disposed in the V-groove of the valve seat 8.

[0119] The sealing gasket 7 is made of rubber and polytetrafluoroethylene, which gives it good chemical corrosion resistance, high temperature resistance, and wear resistance, ensuring a tight seal.

[0120] The sealing gasket 7 is used to ensure the sealing between the valve plate 5 and the valve seat 8, and to prevent fluid leakage between them.

[0121] The valve plate 5, valve seat 8, sealing gasket 7 and torsion spring 6 in this invention form a V-type valve. By controlling the opening and closing of the V-type valve, the opening and closing of the cementing casing string can be controlled. When the V-type valve is closed, pressure continues to be applied to the cementing casing string, which can create a pressure difference between the annulus and the inside of the casing. The V-type valve has the characteristics of simple operation and strong equipment stability.

[0122] Figure 4 A flowchart illustrating the method of using a tailpipe cementing annulus pressure-blocking tool according to an embodiment of the present invention is shown. Figure 4 As shown, based on the above-mentioned tailpipe cementing annulus pressure-blocking tool, this invention also proposes a method for using the tailpipe cementing annulus pressure-blocking tool, including the following steps:

[0123] In actual use, the tailpipe cementing annulus pressure-pressurizing tool is connected to the cementing casing string, and then the tailpipe cementing operation is carried out; wherein, under the restriction of the annular piston 2, the valve plate 5 remains in the normally open state, which does not affect the normal tailpipe cementing operation process.

[0124] After cementing is completed in the tailpipe, a drill pipe plug is pressed in to replace it. The drill pipe plug and the tailpipe plug together cut the hollow shear pin 3. The pressure is transmitted through the through hole formed by the cut hollow shear pin 3 to the second annular cavity formed by the annular piston 2 and the lower connector 9 (the pressure in the second annular cavity is greater than the pressure in the first annular cavity). The drill pipe plug continues to descend until it touches the well, and then pressurizes the well. When the pressure in the second annular cavity is greater than the set pressure, the annular piston 2 slides upward under the action of the pressure difference between the first annular cavity and the second annular cavity. After the annular piston 2 slides upward a set distance, the restriction on the valve plate 5 is released. The valve plate 5 closes under the action of the closing torque of the torsion spring 6 and its own weight.

[0125] Pressurize the well again. At this point, the valve plate 5, under pressure, closes tightly with the valve seat 8. The sealing gasket 7 ensures a tight seal, achieving a sealed state inside the casing. This creates a pressure difference between the annulus and the casing, allowing for annular pressure buildup. The valve plate 5 is then drilled through by lowering the drill bit at the wellhead or pressure built up to 50MPa-60MPa at the wellhead for breakage. Normal well completion operations can then proceed.

[0126] In the description of this invention, it should be understood that the terms "center," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," "counterclockwise," "axial," "radial," and "circumferential" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this invention.

[0127] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one of that feature. In the description of this invention, "a plurality of" means at least two, such as two, three, etc., unless otherwise explicitly specified.

[0128] In this invention, unless otherwise explicitly specified and limited, the terms "installation," "connection," "linking," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components, unless otherwise explicitly limited. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0129] In this invention, unless otherwise explicitly specified and limited, "above" or "below" the second feature can mean that the first feature is in direct contact with the second feature, or that the first feature is in indirect contact with the second feature through an intermediate medium. Furthermore, "above," "over," and "on top" of the second feature can mean that the first feature is directly above or diagonally above the second feature, or simply that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature can mean that the first feature is directly below or diagonally below the second feature, or simply that the first feature is at a lower horizontal level than the second feature.

[0130] In the description of this invention, the terms "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., refer to specific features, structures, materials, or characteristics described in connection with that embodiment or example, which are included in at least one embodiment or example of the invention. In this invention, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in a suitable manner in any one or more embodiments or examples. Moreover, those skilled in the art can combine different embodiments or examples and features of different embodiments or examples described in this invention without contradiction.

[0131] Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A tailpipe cementing annulus pressure-blocking tool, characterized in that, include: Upper connector (1), valve control unit, valve plate (5), valve seat (8) and lower connector (9); The upper connector (1) and the lower connector (9) are fixedly connected; The valve control unit is slidably disposed inside the upper connector (1) and the lower connector (9), and the valve control unit abuts against the upper connector (1) and the lower connector (9) respectively; One end of the valve control unit abuts against one side wall of the valve plate (5); The valve plate (5) is rotatably connected to the valve seat (8); The valve seat (8) is sleeved inside the lower connector (9), and the outer wall of the valve seat (8) abuts against the inner wall of the lower connector (9); The valve seat (8) is tubular, and two V-shaped grooves symmetrical about the center of the valve seat (8) are opened on the side wall.

2. The tailpipe cementing annulus pressure-blocking tool according to claim 1, characterized in that, The valve control unit includes: an annular piston (2); An annular protrusion (10) is fixedly provided on the outer wall of the annular piston (2); the outer wall of the annular protrusion (10) is slidably sealed to the lower connector (9); The outer wall of the top end of the annular piston (2) is slidably sealed to the upper connector (1); The annular piston (2) has a threaded hole on its side wall, and the threaded hole is located below the annular protrusion (10); The bottom surface of the annular piston (2) is inclined, and the inclined surface abuts against the side wall of the valve plate (5).

3. The tailpipe cementing annulus pressure-blocking tool according to claim 2, characterized in that, The valve control unit also includes: a hollow shear pin (3); The hollow shear pin (3) is disposed in the threaded hole of the annular piston (2); The hollow inner diameter of the hollow shear pin (3) is 2-8 mm.

4. A tailpipe cementing annulus pressure-blocking tool according to claim 2 or 3, characterized in that, The valve control unit also includes: a sealing ring (4); One or more parallel annular grooves are provided on the middle part of the inner wall of the lower connector (9); The sealing ring (4) is fixedly installed in the annular groove of the lower connector (9); The sealing ring (4) is provided with one or more; The outer wall of the annular piston (2) is slidably connected to the inner wall of the lower connector (9) through a sealing ring (4).

5. A tailpipe cementing annulus pressure-blocking tool according to claim 4, characterized in that, The annular protrusion (10) divides the cavity between the upper connector (1), the lower connector (9), the annular piston (2) and the sealing ring (4) into a first annular cavity and a second annular cavity; The working pressure range of the second annular cavity is 20-70 MPa.

6. A tailpipe cementing annulus pressure-blocking tool according to claim 1, characterized in that, The tailpipe cementing annulus pressure-blocking tool also includes: torsion spring (6); One end of the torsion spring (6) is connected to the valve plate (5), and the other end of the torsion spring (6) is connected to the valve seat (8).

7. A tailpipe cementing annulus pressure-blocking tool according to claim 1, characterized in that, The valve plate (5) is V-shaped as a whole; The valve plate (5) is matched with the V-groove. When the valve plate (5) is closed, the valve plate (5) is positioned in the V-groove of the valve seat (8).

8. A tailpipe cementing annulus pressure-blocking tool according to claim 1 or 7, characterized in that, The included angle of the V-groove is 90°.

9. A tailpipe cementing annulus pressure-blocking tool according to claim 7, characterized in that, The tailpipe cementing annulus pressure-blocking tool also includes: a sealing gasket (7); The sealing gasket (7) is V-shaped and is located in the V-groove of the valve seat (8).

10. A method of using the tailpipe cementing annulus pressure-blocking tool according to any one of claims 1-9, characterized in that, Includes the following steps: Connect the tailpipe cementing annulus pressure-blocking tool to the cementing casing string, and then carry out tailpipe cementing operations; wherein, under the restriction of the annular piston (2), the valve plate (5) remains in the normally open state; After the tailpipe is cemented, the drill pipe plug is pressed in to replace it. The drill pipe plug and the tailpipe plug together cut off the hollow shear pin (3). The drill pipe plug continues to descend until it touches the pressure. Then, pressure is applied to the well. When the pressure in the second annular cavity is greater than the set pressure, the annular piston (2) slides upward. When the annular piston (2) slides upward a set distance, it releases the restriction on the valve plate (5), and the valve plate (5) closes under the action of the closing torque of the torsion spring (6) and its own weight; Pressurize the well again, and the valve plate (5) will be subjected to pressure and close tightly with the valve seat (8).

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