Reverse circulation valve

Abstract

The utility model belongs to the field of valves in wells, and particularly relates to a reverse circulation valve. In order to prolong the service life of the reverse circulation valve and save cost, the utility model provides the reverse circulation valve. The reverse circulation valve comprises a spring, a piston, an upper connector, an outer cylinder and a lower connector, a pressure transmitting hole is formed in the outer cylinder, and the piston comprises a pressure bearing face used for bearing pressure. The piston is located in the outer cylinder, the upper connector or the outer cylinder comprises a spring installation face, the spring is installed between the spring installation face and the piston, the lower connector or the outer cylinder comprises a limiting part, the limiting part is used for limiting the limiting position of downward movement of the piston, and a radial through hole used for being aligned with the pressure transmitting hole during inverse well flushing is formed in the piston; and the inner diameter of the pressurizing seat is smaller than the inner diameters of the upper joint, the lower joint and the outer cylinder. The pressurizing seat is additionally arranged on the piston, and when the spring cannot reset the piston, external force is applied to the pressurizing seat to drive the piston to reset, so that the service life of the reverse circulation valve is prolonged, and the cost is saved.

Description

Technical Field

[0001] This utility model belongs to the field of valves in wells, and in particular relates to a reverse circulation valve. Background Technology

[0002] Backwashing wells requires a reverse circulation valve, which is connected to the production tubing string. During normal production, the reverse circulation valve is closed. When backwashing is needed, pressure is applied from the wellhead into the annulus to open the valve, thus connecting the tubing cavity and the annulus for backwashing. In actual production, the reverse circulation valve can be repeatedly opened or closed as needed.

[0003] Chinese utility model patent CN202249949U, with an authorization announcement date of May 30, 2012, discloses an external pressure-opening reverse circulation valve. This reverse circulation valve includes an upper connector, an outer sleeve, a piston, and a spring. The lower end of the upper connector is threadedly connected to the upper end of the outer sleeve. The outer sleeve has a mounting step. The piston is located inside the outer sleeve, and the spring is compressed between the spring mounting surface of the mounting step and the piston. The outer sleeve has a radial through hole (i.e., a pressure transmission hole). The piston includes a boss communicating with the radial through hole and used for bearing pressure. The lower half of the outer sleeve has external threads to form a lower connector for connection to a lower oil pipe.

[0004] When backwashing is required, pressure is applied from the wellhead into the annulus. The pressure is transmitted through the radial through-hole to the bearing surface of the boss. The piston moves and compresses the spring until the radial through-hole connects with the inner cavity of the reverse circulation valve, that is, the inner cavity of the tubing connects with the annulus, thus enabling backwashing. After backwashing is completed, pressure is stopped from the annulus. The pressure on the boss decreases, and the spring pushes the piston back to its original position, causing the piston to re-seal the radial through-hole. At this point, the inner cavity of the tubing is no longer connected to the annulus, thus enabling normal production.

[0005] When the aforementioned reverse circulation valve is used for an extended period, the spring gradually fails due to corrosion, causing the piston to fail to return to its original position and the reverse circulation valve to fail to close. In this case, the tubing string must be removed and the reverse circulation valve replaced. Because the reverse circulation valve has a short lifespan, the tubing string needs to be frequently removed and replaced, resulting in high costs. Utility Model Content

[0006] The purpose of this invention is to provide a reverse circulation valve to solve the technical problem of short lifespan of reverse circulation valves.

[0007] To achieve the above objectives, the technical solution of the reverse circulation valve provided by this utility model is as follows:

[0008] A reverse circulation valve includes a spring, a piston, and an upper connector, an outer cylinder, and a lower connector connected sequentially from top to bottom. The outer cylinder has a pressure transmission hole, and the piston includes a pressure-bearing surface that communicates with the pressure transmission hole and is used for bearing pressure. The piston is located inside the outer cylinder, or the piston is located inside the outer cylinder and the lower connector. The upper connector or the outer cylinder includes a spring mounting surface, and the spring is installed between the spring mounting surface and the piston. The lower connector or the outer cylinder includes a limiting part for limiting the extreme position of the piston's downward movement. The piston has a radial through hole for aligning with the pressure transmission hole during backwashing and for misaligning with the pressure transmission hole during normal production. The piston also has a pressure seat, the inner diameter of which is smaller than the inner diameter of the upper and lower connectors and the outer cylinder.

[0009] Furthermore, the pressure seat is a ball seat used in conjunction with a soluble drop ball.

[0010] Furthermore, the pressure seat is an impact seat used to mate with the impact head.

[0011] Furthermore, the piston includes a fixedly connected intermediate tube and an inner tube, with a pressure seat disposed on the inner tube. The intermediate tube and the inner tube are respectively provided with a first radial sub-through hole and a second radial sub-through hole, which are interconnected and constitute the radial through hole.

[0012] Furthermore, the lower end of the intermediate tube is fixedly connected to the lower end of the inner tube, and a sealing ring is provided between the upper end of the inner tube and the intermediate tube, with the sealing ring located above the radial through hole.

[0013] Furthermore, the reverse circulation valve also includes a core tube located inside the upper connector and the outer cylinder. The upper end of the core tube is fixedly connected to the upper connector. The outer diameter of the inner tube is larger than the inner diameter of the core tube, and the inner diameter of the inner tube is smaller than the inner diameter of the core tube. The vertical distance between the core tube and the inner tube is equal to the vertical distance between the connecting hole and the pressure transmitting hole.

[0014] Furthermore, the lower connector includes a limiting cone surface, the minimum inner diameter of which is smaller than the outer diameter of the lower end of the inner and intermediate tubes, and the limiting cone surface constitutes the limiting part.

[0015] Furthermore, the reverse circulation valve also includes a core tube located inside the upper connector and the outer cylinder, with the upper end of the core tube fixedly connected to the upper connector and a spring disposed between the core tube and the outer cylinder.

[0016] Furthermore, the piston and the core tube are in a sliding seal fit.

[0017] Furthermore, the upper end of the core tube is provided with an external thread, and the lower end of the upper connector is provided with an internal thread, and the core tube is threadedly connected to the upper connector.

[0018] The beneficial effects of the reverse circulation valve provided by this utility model are as follows: This utility model is an improved invention. The core difference between this utility model and the prior art is that a pressure seat is added to this utility model to achieve the downward reset of the piston.

[0019] Based on the above core differences, in actual use, when the spring fails and the piston cannot be reset, force can be applied to the pressure seat by throwing a ball or other means, so that the pressure seat can drive the piston to reset.

[0020] To facilitate understanding of this utility model by those skilled in the art, the beneficial effects of this utility model will be described in detail below in conjunction with specific usage.

[0021] When backwashing is required, pressure is applied from the wellhead into the annulus. The pressure is transmitted to the pressure-bearing surface through the pressure transmission hole. The piston moves and compresses the spring until the radial through hole aligns with the pressure transmission hole. At this point, the tubing cavity is connected to the annulus, thus enabling backwashing.

[0022] After backwashing is completed, pressure is stopped being applied to the annulus. The pressure on the pressure-bearing surface decreases, and the spring pushes the piston back to its original position so that the piston re-seals the pressure transmission hole. At this time, the pressure transmission hole and the radial through hole are misaligned, and the tubing cavity is no longer connected to the annulus, thus enabling normal production.

[0023] After backwashing is completed, if the spring fails, a pressurizing tool can be lowered into the tubing. Since the inner diameter of the pressurizing seat is smaller than the inner diameter of the upper and lower connectors and the outer cylinder, the pressurizing tool can apply a downward force to the pressurizing seat, thereby causing the piston to return to its original position and re-seal the pressure transmission hole. At this time, the pressure transmission hole and the radial through hole are misaligned, and the tubing cavity is not connected to the annulus of the tubing and casing, thus enabling normal production.

[0024] Among them, the pressurization tools can be commonly used pressurization tools in oil wells, such as soluble drop balls and impact heads. Attached Figure Description

[0025] Figure 1 This is a schematic diagram of the reverse circulation valve of this utility model during normal production.

[0026] Figure 2 This is a schematic diagram of the reverse circulation valve of this utility model during backwashing.

[0027] Figure 3 This is a schematic diagram of the structure when the reverse circulation valve of this utility model is closed using a soluble drop ball;

[0028] Figure 4 This is a schematic diagram of the structure when the reverse circulation valve of this utility model is closed using an impact head.

[0029] Explanation of reference numerals in the attached figures:

[0030] 1. Upper connector; 2. Outer cylinder; 2a. Pressure transmission hole; 3. Spring; 4. Core tube; 5. Intermediate tube; 5a. First radial through hole; 6. Inner tube; 6a. Second radial through hole; 7. Lower connector; 7a. Limiting part; 8. Soluble drop ball; 9. Impact head. Detailed Implementation

[0031] To address the problems in the background art, the core inventive concept of this utility model is to add a pressure seat to the piston, and when the spring 3 fails to reset the piston, to drive the piston to reset by applying an external force to the pressure seat.

[0032] The present invention will be further described in detail below with reference to embodiments of the reverse circulation valve.

[0033] like Figures 1-4 As shown, in a basic specific embodiment, the reverse circulation valve includes a spring 3, a piston, and an upper connector 1, an outer cylinder 2, and a lower connector 7 connected sequentially from top to bottom. The outer cylinder 2 is provided with a pressure transmission hole 2a. The piston includes a pressure-bearing surface that communicates with the pressure transmission hole 2a and is used for bearing pressure. The piston is located inside the outer cylinder 2, or the piston is located inside the outer cylinder 2 and the lower connector 7. The upper connector 1 or the outer cylinder 2 includes a spring mounting surface, and the spring 3 is installed between the spring mounting surface and the piston. The lower connector 7 or the outer cylinder 2 includes a limiting part 7a, which is used to limit the extreme position of the piston's downward movement. The piston is provided with a radial through hole for aligning with the pressure transmission hole 2a during backwashing and for misaligning with the pressure transmission hole 2a during normal production. The piston is also provided with a pressure seat, the inner diameter of which is smaller than the inner diameter of the upper and lower connectors 7 and the outer cylinder 2.

[0034] The upper connector 1 is used to connect to the upper oil pipe, and the lower connector 7 is used to connect to the lower oil pipe. The upper connector 1, the outer cylinder 2, and the lower connector 7 are connected by threaded connections or welding, etc. The upper connector 1 and the outer cylinder 2 can also be integrally formed. Figure 1 In the illustrated embodiment, the piston is located both inside the outer cylinder 2 and the lower connector 7; however, in other embodiments, the length of the piston can be shortened so that the piston is located only inside the outer cylinder 2. Figure 1 In the illustrated embodiment, the outer connector includes a limiting portion 7a; however, in other embodiments, the outer cylinder 2 may also include a cylinder body and a limiting protrusion disposed on the inner wall of the cylinder body, the limiting protrusion constituting the limiting portion 7a; Figure 1 In the embodiment shown, the lower end face of the lower connector 7 constitutes the spring mounting surface. In other embodiments, referring to the Chinese Utility Model Patent with authorization announcement number CN202249949U, the lower connector 7 or the outer cylinder 2 may also include a mounting step, and the step surface of the mounting step facing the spring 3 constitutes the spring mounting surface.

[0035] In this invention, since the piston needs to be pressed down by a pressure tool, the spring 3 is placed above the piston to allow the piston to return to its original position.

[0036] To facilitate understanding of this utility model by those skilled in the art, the beneficial effects of this utility model will be described in detail below in conjunction with specific usage.

[0037] When backwashing is required, pressure is applied from the wellhead into the annulus. The pressure is transmitted to the pressure-bearing surface through the pressure transmission hole 2a. The piston moves and compresses the spring 3 until the radial through hole aligns with the pressure transmission hole 2a. At this point, if... Figure 2 As shown, the tubing cavity is connected to the annulus of the casing, thus enabling backwashing of the well.

[0038] After backwashing is completed, pressure is stopped from entering the annulus. The pressure on the bearing surface decreases, and spring 3 pushes the piston back to its original position, causing the piston to re-seal the pressure transmission hole 2a. At this time, if... Figure 1 As shown, the pressure transmission hole 2a is misaligned with the radial through hole, and the inner cavity of the oil pipe is not connected to the annulus of the oil sleeve, thus enabling normal production.

[0039] After backwashing is completed, if spring 3 fails, a pressurizing tool can be lowered into the tubing. Since the inner diameter of the pressurizing seat is smaller than the inner diameter of the upper and lower connectors and the outer cylinder 2, the pressurizing tool can apply a downward force to the pressurizing seat, thereby causing the piston to return to its original position and re-seal the pressure transmission hole 2a. At this time, the pressure transmission hole 2a is misaligned with the radial through hole, and the tubing cavity is not connected to the annulus of the tubing, thus enabling normal production.

[0040] Among them, the pressurizing tools can be commonly used pressurizing tools in oil wells, such as the soluble drop ball 8 and the impact head.

[0041] exist Figure 3 In the illustrated embodiment, the pressure seat is a ball seat for engaging with the soluble drop ball 8. When the spring 3 fails, the soluble drop ball 8 is dropped into the oil pipe, where it sits on the ball seat and pressurizes the oil pipe. The pressure is transmitted to the pressure seat through the soluble drop ball 8 (i.e., the soluble drop ball 8 applies a downward force to the pressure seat), thereby causing the piston to return to its downward position.

[0042] After a period of time, the soluble ball 8 was dissolved, the oil pipe was restored to its normal flow, and normal production was able to proceed.

[0043] exist Figure 4 In the illustrated embodiment, the pressure seat is an impact seat used to cooperate with the impact head 9. When the spring 3 fails, the impact head 9 (the upper end of the impact head 9 is threadedly connected to a wire cap, and the wire cap is connected to the wire string) is lowered into the oil pipe using a steel wire. Under the action of the steel wire and its own weight, the impact head 9 strikes the impact seat downward (i.e., the impact head 9 applies a downward force to the pressure seat), thereby causing the piston to return to its downward position.

[0044] like Figures 1-4 As shown, in one embodiment, the piston includes a fixedly connected intermediate tube 5 and an inner tube 6. A pressure seat is disposed on the inner tube 6. The intermediate tube 5 and the inner tube 6 are respectively provided with a first radial sub-through hole 5a and a second radial sub-through hole 6a. The first radial sub-through hole 5a and the second radial sub-through hole 6a are interconnected and constitute the radial through hole, which has a simple structure.

[0045] Preferably, in one embodiment, the lower end of the intermediate tube 5 is fixedly connected to the lower end of the inner tube 6, and a sealing ring is provided between the upper end of the inner tube 6 and the intermediate tube 5. The sealing ring is located above the radial through hole, so that all the liquid enters the cavity inside the piston through the second radial through hole 6a.

[0046] Among them, Figures 1-4 In the embodiment shown, the lower end of the intermediate tube 5 has an internal thread, the lower end of the inner tube 6 has an external thread, and the intermediate tube 5 is threadedly connected to the outer tube.

[0047] In other embodiments, the intermediate tube 5 and the outer tube can be fixedly connected by welding or other methods.

[0048] In other embodiments, a sealing ring may not be provided between the intermediate pipe 5 and the inner pipe 6, and the intermediate pipe 5 and the oil pipe may be fitted with a clearance to achieve a seal.

[0049] In other embodiments, the piston may also be an integral structure, with a pressure seat such as a ball seat or an impact seat machined on the piston, and the radial through hole is a separate through hole.

[0050] In a preferred embodiment, such as Figures 1-2 As shown, the reverse circulation valve also includes a core tube 4 located inside the upper connector 1 and the outer cylinder 2. The upper end of the core tube 4 is fixedly connected to the upper connector 1. The outer diameter of the inner tube 6 is larger than the inner diameter of the core tube 4, and the inner diameter of the inner tube 6 is smaller than the inner diameter of the core tube 4. The vertical distance between the core tube 4 and the inner tube 6 is equal to the vertical distance between the connecting hole and the pressure transmitting hole 2a. During the upward movement of the piston, the core tube 4 will stop the piston, preventing the piston from continuing to move upward. Figure 2 As shown, since the vertical distance between the core tube 4 and the inner tube 6 is equal to the vertical distance between the connecting hole and the pressure transmission hole 2a, when the core tube 4 stops the piston, the pressure transmission hole 2a is exactly aligned with the radial through hole, which facilitates the piston to quickly reach the position.

[0051] Among them, Figure 1 In the embodiment shown, the upper end of the core tube 4 is provided with an external thread, and the lower end of the upper connector 1 is provided with an internal thread. The core tube 4 is threadedly connected to the upper connector 1.

[0052] In other embodiments, the core tube 4 can also be fixedly connected to the upper connector 1 by welding or other means.

[0053] In other embodiments, the core tube 4 may not be provided. After the pressure transmission hole 2a is aligned with the radial through hole, since the oil sleeve annulus is connected to the inside of the oil pipe, the pressure inside the oil sleeve annulus is equal to the pressure inside the oil pipe. Therefore, the liquid will no longer provide upward power for the piston, but will instead provide resistance during the piston's upward movement, so that the piston eventually stops in the state where the pressure transmission hole 2a is aligned with the radial through hole.

[0054] In other embodiments, the vertical distance between the core tube 4 and the inner tube 6 may also be greater than the vertical distance between the connecting hole and the pressure transmitting hole 2a.

[0055] In a preferred embodiment, such as Figures 1-2 As shown, the spring 3 is positioned between the core tube 4 and the outer cylinder 2. The core tube 4 and the outer cylinder 2 can protect the spring 3, preventing unknown objects from impacting the spring 3 under complex working conditions downhole, thus extending the life of the spring 3.

[0056] In other embodiments, as shown in Chinese Utility Model Patent No. CN202249949U, the core tube 4 may not be provided, and the object inside the oil tube may directly contact the spring 3.

[0057] In a preferred embodiment, such as Figures 1-2 As shown, the piston and core tube 4 are in a sliding seal fit. At this time, since the piston and outer cylinder 2 are also in a sliding seal fit, the chamber formed by the core tube 4, piston, outer cylinder 2, and upper connector 1 is a sealed chamber (when the spring mounting surface is set on the outer cylinder 2, the chamber formed by the core tube 4, piston, and outer cylinder 2 is a sealed chamber), and the spring 3 is located within the sealed chamber. Therefore, liquid will not enter the sealed chamber and come into contact with the spring 3, effectively preventing corrosion of the spring 3, extending the life of the spring 3, and thus extending the life of the reverse circulation valve.

[0058] exist Figures 1-2 In the embodiment shown, the piston and the core tube 4 are fitted with a clearance to achieve a seal.

[0059] In other embodiments, a sealing ring may be added between the piston and the core tube 4.

[0060] In one embodiment, such as Figure 1 As shown, the lower connector 7 includes a limiting cone surface. The minimum inner diameter of the limiting cone surface is smaller than the outer diameter of the lower end of the inner and intermediate tubes 5. The limiting cone surface constitutes the limiting part 7a, which has a simple structure.

[0061] In other embodiments, the lower connector 7 may also include a connector body and a limiting protrusion disposed on the inner peripheral surface of the connector body, the limiting protrusion constituting the limiting portion 7a.

[0062] In this invention, sealing rings can be provided at the threaded connection and on both the upper and lower sides of the pressure transmission hole 2a to improve the sealing performance.

[0063] Finally, it should be noted that the above are merely preferred embodiments of this utility model and are not intended to limit the utility model. Although the utility model has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments without creative effort, or make equivalent substitutions for some technical features, or organically combine different specific implementation methods to create the specific implementation methods shown in the accompanying drawings. Of course, those skilled in the art can also create other specific implementation methods not shown in the accompanying drawings. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this utility model should be included within the protection scope of this utility model.

Claims

1. A reverse circulation valve, comprising a spring, a piston, and an upper connector, an outer cylinder, and a lower connector connected sequentially from top to bottom, wherein the outer cylinder has a pressure-transmitting hole, and the piston includes a pressure-bearing surface communicating with the pressure-transmitting hole and used for bearing pressure; the piston is located inside the outer cylinder, or the piston is located inside the outer cylinder and the lower connector, characterized in that, The upper connector or outer cylinder includes a spring mounting surface, with the spring mounted between the spring mounting surface and the piston. The lower connector or outer cylinder includes a limiting part, which limits the extreme position of the piston's downward movement. The piston is provided with a radial through hole for alignment with the pressure transmission hole during backwashing and for misalignment with the pressure transmission hole during normal production. The piston is also provided with a pressure seat, the inner diameter of which is smaller than the inner diameter of the upper and lower connectors and the outer cylinder.

2. The reverse circulation valve as described in claim 1, characterized in that, The pressure seat is a ball seat used in conjunction with a soluble drop ball.

3. The reverse circulation valve as described in claim 1, characterized in that, The pressure seat is an impact seat used to mate with the impact head.

4. The reverse circulation valve as described in any one of claims 1 to 3, characterized in that, The piston includes a fixedly connected intermediate tube and an inner tube. A pressure seat is disposed on the inner tube. The intermediate tube and the inner tube are respectively provided with a first radial sub-through hole and a second radial sub-through hole. The first radial sub-through hole and the second radial sub-through hole are interconnected and constitute the radial through hole.

5. The reverse circulation valve as described in claim 4, characterized in that, The lower end of the intermediate tube is fixedly connected to the lower end of the inner tube, and a sealing ring is provided between the upper end of the inner tube and the intermediate tube. The sealing ring is located above the radial through hole.

6. The reverse circulation valve as described in claim 4, characterized in that, The reverse circulation valve also includes a core tube located inside the upper connector and the outer cylinder. The upper end of the core tube is fixedly connected to the upper connector. The outer diameter of the inner tube is larger than the inner diameter of the core tube, and the inner diameter of the inner tube is smaller than the inner diameter of the core tube. The vertical distance between the core tube and the inner tube is equal to the vertical distance between the connecting hole and the pressure transmitting hole.

7. The reverse circulation valve as described in claim 4, characterized in that, The lower connector includes a limiting cone surface, the minimum inner diameter of which is smaller than the outer diameter of the lower end of the inner and intermediate tubes, and the limiting cone surface constitutes the limiting part.

8. The reverse circulation valve as described in any one of claims 1 to 3, characterized in that, The reverse circulation valve also includes a core tube located inside the upper connector and the outer cylinder. The upper end of the core tube is fixedly connected to the upper connector, and a spring is disposed between the core tube and the outer cylinder.

9. The reverse circulation valve as described in claim 8, characterized in that, The piston and the core tube are in a sliding seal fit.

10. The reverse circulation valve as described in claim 8, characterized in that, The upper end of the core tube is provided with an external thread, and the lower end of the upper connector is provided with an internal thread. The core tube and the upper connector are threadedly connected.

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