A downhole choke for oil and gas production

Abstract

This invention discloses a downhole throttling device suitable for oil and gas extraction. It is installed inside the wellbore and includes a connecting assembly, a central tube, a sand-control assembly, and a sealing assembly. The upper end of the central tube is connected to the connecting assembly, the sand-control assembly is connected to the lower end of the central tube, and the sealing assembly is fitted onto the central tube with its lower end connected to the central tube. The sealing assembly includes a nozzle, a rubber sleeve sealing assembly, and a fixing assembly. When in the throttling state, the outer surface of the rubber sleeve sealing assembly is compressed and seals against the inner surface of the wellbore. This invention separates the sealing assembly into a rubber sleeve sealing assembly and a fixing assembly, connecting the fixing assembly and the rubber sleeve sealing assembly via the central tube. The movement of the central tube is controlled by the connecting assembly. That is, during the movement of the central tube, the rubber sleeve sealing assembly and the fixing assembly are simultaneously activated, achieving a separate design for the fixing assembly and the rubber sleeve sealing assembly, while also achieving synchronous control of the fixing assembly and the rubber sleeve sealing assembly.

Description

Technical Field

[0001] This invention relates to the field of oil and gas extraction technology, and more specifically to a downhole choke suitable for oil and gas extraction. Background Technology

[0002] Downhole throttling devices are placed in the well casing at a certain depth to achieve throttling and pressure reduction in the wellbore, converting pressure energy into kinetic energy, increasing the fluid flow velocity, keeping the throttled fluid in a critical flow state, reducing the impact of wellhead pressure fluctuations on the well bottom, and making full use of geothermal energy to prevent the formation of hydrates.

[0003] Downhole chokes are further divided into slip-type downhole chokes and pre-installed downhole chokes based on their setting method. Because downhole chokes need to be adjusted in a timely manner according to the production situation during oil and gas extraction, slip-type downhole chokes are more commonly used. However, at present, most slip-type downhole chokes are installed in the well casing and the well casing is sealed by a fixing component. This may result in insecure fixing or poor sealing.

[0004] Some downhole chokes separate the fixing component and the sealing component, but when installing the downhole choke, the fixing component and the sealing component need to be installed separately, which is a rather cumbersome operation. Summary of the Invention

[0005] The technical problem to be solved by the present invention is that the integrated design of the fixing component and the sealing component may result in poor fixing or poor sealing, while the separate setting of the fixing component and the sealing component will result in cumbersome installation. The purpose is to provide a downhole choke suitable for oil and gas extraction, which solves the problem of how to install the separate fixing component and the sealing component at one time.

[0006] This invention is achieved through the following technical solution:

[0007] A downhole choke suitable for oil and gas extraction, which is installed inside the wellbore, includes:

[0008] Connection components;

[0009] A central tube having an upper end and a lower end, the upper end of which is connected to the connecting assembly;

[0010] A sand-proof component, which is connected to the lower end of the central tube;

[0011] A sealing assembly having an upper end and a lower end, the sealing assembly being fitted onto the central tube, and the lower end of the sealing assembly being connected to the central tube, the sealing assembly comprising:

[0012] The nozzle sleeve has its lower end connected to the lower end of the central tube, and the nozzle sleeve is provided with a throttling nozzle for connecting the central tube and the sand-proof component.

[0013] A rubber sleeve sealing assembly is fitted onto the central tube, and the lower end face of the rubber sleeve sealing assembly contacts the upper end face of the nozzle sleeve.

[0014] A fixing component is fitted onto the central tube and has an upper end and a lower end. The lower end face of the fixing component contacts the upper end face of the rubber sleeve sealing component, and the fixing component is slidably connected to the central tube.

[0015] When in a throttling state, the outer side of the rubber sleeve sealing assembly is sealed and fitted to the inner side of the well casing after being compressed.

[0016] Specifically, the connection component includes:

[0017] A release connector having an upper end and a lower end, the upper end of which is connected to a shock absorber;

[0018] A pin-operated shear sleeve has a first inner hole section and a second inner hole section arranged coaxially. The lower end of the release connector is disposed in the first inner hole section and the release connector is threadedly connected to the first inner control section. The upper end of the central tube is disposed in the second inner hole section and the central tube is connected to the second inner hole section by a release pin.

[0019] Specifically, the sand-proof component includes:

[0020] A sand shield has an upper end and a lower end. The upper end of the sand shield is sealed to the outer side of the mouthpiece. The sand shield is provided with multiple sand-proof through holes that penetrate the inside and outside.

[0021] A cut-and-seam gold tube is fixedly installed inside the sandproof cover, and the cut-and-seam gold tube has multiple slits that penetrate through the inside and outside.

[0022] The tail plug is sealed to the lower end of the sand shield.

[0023] Specifically, the rubber sleeve sealing assembly includes:

[0024] A glue cartridge assembly is fitted onto the central tube, with its lower end face contacting the nozzle sleeve and its upper end face contacting the fixing component.

[0025] Furthermore, the rubber sleeve sealing assembly also includes:

[0026] A sealing seat is disposed between the rubber sleeve assembly and the central tube, the sealing seat comprising:

[0027] A straight cylinder is fitted onto the central tube, and the inner side of the straight cylinder slides and seals with the outer side of the central tube, while the inner side of the upper end of the nozzle sleeve slides and contacts the outer side of the lower end of the straight cylinder.

[0028] A circular ring is coaxially fitted onto the straight cylinder, and the inner ring surface of the circular ring is fixedly connected to the outer surface of the straight cylinder.

[0029] The glue cartridge assembly includes:

[0030] First glue tube;

[0031] The second rubber tube, the first rubber tube and the second rubber tube are both fitted onto the straight cylinder and located on both sides of the ring. The lower end face of the fixing component is in contact with the upper end face of the first rubber tube, and the upper end face of the nozzle is in contact with the lower end face of the second rubber tube.

[0032] Specifically, the sealing assembly further includes a backlash prevention and release component, which is disposed between the rubber sleeve sealing assembly and the fixing assembly. The backlash prevention and release component includes:

[0033] A sleeve, the upper end of which is connected to the fixing component, the inner side of the lower end of the sleeve slidingly contacts the outer side of the upper end of the straight cylinder, and an annular cavity is provided between the sleeve and the central tube.

[0034] The C-ring has an inner ratchet tooth on its inner side, and the inner side of the annular cavity has an outer ratchet tooth that matches the inner ratchet tooth.

[0035] A shearing ring, the upper end face of which contacts the lower end face of the C ring, the shearing ring is disposed in the annular cavity, and the outer side of the annular cavity is provided with a through pin hole, and the outer side of the shearing ring is provided with a pin blind hole adapted to the pin hole.

[0036] Unseal the pin, which passes through the pin hole and connects to the pin blind hole, and fixes the shear ring and the sleeve.

[0037] As one embodiment, the angle between the deflection angle of the internal ratchet and the upper end direction of the central tube is an acute angle;

[0038] The angle between the deflection angle of the external ratchet and the lower end direction of the central tube is an acute angle.

[0039] Specifically, the fixing component includes:

[0040] A fixed cylinder has a straight section and a tapered section, the lower end of the straight section is fixedly connected to the small-diameter end of the tapered section, and the large-diameter end of the tapered section is connected to the upper end of the sleeve.

[0041] The upper end of the slip is fitted onto the straight section of the fixed cylinder, and the lower end of the slip is attached to the outer side of the conical section of the fixed cylinder.

[0042] The conical section of the fixed cylinder applies an outward force along the radial direction to the lower end of the slip.

[0043] In one embodiment, the fixing component further includes a retrieval neck, which is fixedly connected to the upper end of the slip.

[0044] As another embodiment, the kava includes:

[0045] The upper ring is fitted onto the fixed cylinder;

[0046] The tiles are arranged along the central axis of the fixed cylinder, with the upper ends of the tiles fixedly connected to the upper ring and the lower ends of the tiles attached to the conical section of the fixed cylinder.

[0047] When in a throttling state, the lower outer surface of the tile abuts against the inner surface of the well shaft.

[0048] Compared with the prior art, the present invention has the following advantages and beneficial effects:

[0049] The present invention divides the sealing component into a rubber sleeve sealing component and a fixing component, and connects the fixing component and the rubber sleeve sealing component through a central tube. The movement of the central tube is controlled by the connecting component. That is, during the movement of the central tube, the rubber sleeve sealing component and the fixing component are operated simultaneously, realizing the separate design of the fixing component and the rubber sleeve sealing component, while also realizing the synchronous control of the fixing component and the rubber sleeve sealing component.

[0050] This invention reduces the amount of sand in the fluid entering the throttling nozzle by setting up a dual sand-proof mechanism of sand-proof cover and cut-and-seamless tube;

[0051] This invention achieves a better sealing effect by setting up a two-stage sealing structure with a first rubber tube and a second rubber tube.

[0052] This invention integrates the anti-retraction and unsealing devices, and separates the functions of the upper and lower operating central tubes into anti-retraction and unsealing functions. This allows the operator to achieve the functions of sealing and retrieval simply by operating the central tube, and the above functions can be achieved simply by moving the central tube up and down without the need for additional operations, thus simplifying the operation. Attached Figure Description

[0053] The accompanying drawings illustrate exemplary embodiments of the present invention and, together with the description thereof, serve to explain the principles of the invention. These drawings are included to provide a further understanding of the invention and are incorporated in and constitute a part of this specification, but do not constitute a limitation on the embodiments of the present invention.

[0054] Figure 1 This is a schematic diagram of a downhole throttle device suitable for oil and gas extraction according to the present invention.

[0055] Figure 2 This is a schematic diagram of the structure of the connection component according to the present invention.

[0056] Figure 3 This is a structural schematic diagram of the sand-proof assembly according to the present invention.

[0057] Figure 4 This is a schematic diagram of the structure of the rubber sleeve sealing assembly according to the present invention.

[0058] Figure 5 This is a structural schematic diagram of the fixing component according to the present invention.

[0059] Figure 6 This is a partial cross-sectional view of the anti-retraction and unsealing assembly according to the present invention.

[0060] Attached reference numerals: 1-Disposable connector, 2-Pin shear sleeve, 3-Center tube, 4-Fixing cylinder, 5-Retrieving neck, 6-Slipper, 7-Clamp, 8-Sleeve, 9-C-ring, 10-Shearing ring, 11-First rubber sleeve, 12-Sealing seat, 13-Nose sleeve, 14-Throttle nozzle, 15-Sand shield, 16-Cut seam metal tube, 17-Tail plug, 91-Inner ratchet, 92-Outer ratchet, 93-Unsealing pin. Detailed Implementation

[0061] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are for illustrative purposes only and are not intended to limit the scope of the invention.

[0062] It should also be noted that, for ease of description, only the parts relevant to the present invention are shown in the accompanying drawings.

[0063] Where there is no conflict, the embodiments and features described in the present invention can be combined with each other. The present invention will now be described in detail with reference to the accompanying drawings and embodiments.

[0064] It should be noted that the "upper" and "lower" directions in this invention are the "left" and "right" directions in the accompanying drawings. In use, taking the liquid flow direction in the well pipe as an example, the lower direction is located upstream of the upper direction.

[0065] Example 1

[0066] like Figure 1 As shown, this embodiment provides a downhole choke suitable for oil and gas extraction, which is installed inside the wellbore and includes a connecting assembly, a central tube 3, a sand control assembly, and a sealing assembly.

[0067] The connecting component in this embodiment is mainly used to connect the downhole choke to the shock absorber. The shock absorber then actuates the downhole choke to achieve the purpose of setting and retrieving the device.

[0068] The central tube 3 has an upper end and a lower end. It is a tube with a central hole, which is used to discharge the throttled fluid. The upper end of the central tube 3 is connected to the connecting assembly.

[0069] The sand control component is connected to the lower end of the central tube 3. It is used to prevent sand from entering the fluid in the central tube 3 and to prevent sand and gravel from entering the downhole choke.

[0070] The sealing assembly has an upper end and a lower end. The sealing assembly is fitted onto the central tube 3, and the lower end of the sealing assembly is connected to the central tube 3. In this embodiment, the sealing assembly has two functions: firstly, it seals the outer surface of the downhole choke between the outer surface of the downhole choke and the inner surface of the well casing, allowing fluid to be discharged only from inside the central tube 3; secondly, it secures the downhole choke to the well casing, ensuring its position is fixed.

[0071] The sealing assembly includes a nozzle sleeve 13, a rubber sleeve sealing assembly, and a fixing assembly.

[0072] The lower end of the nozzle sleeve 13 is connected to the lower end of the central tube 3, and a throttle nozzle 14 for connecting the central tube 3 and the sand-proof component is provided inside the nozzle sleeve 13.

[0073] In this embodiment, the mouthpiece 13 is provided with a through hole, and the lower end of the central tube 3 is disposed in the through hole and is threadedly connected to the lower end of the through hole by a thread, thereby fixing the mouthpiece 13 and the central tube 3.

[0074] The throttle nozzle 14 is located at the lower end of the through hole of the nozzle sleeve 13 and connects the central tube 3 with the sand control assembly. The fluid in the sand control assembly needs to pass through the throttle nozzle 14 before entering the central tube 3.

[0075] The rubber sleeve sealing assembly is fitted onto the central tube 3, and the lower end face of the rubber sleeve sealing assembly contacts the upper end face of the nozzle sleeve 13. The rubber sleeve sealing assembly is not fixedly connected to the central tube 3. When the central tube 3 moves upward, it pulls the nozzle sleeve 13 upward, and the nozzle sleeve 13 applies an upward force to the rubber sleeve sealing assembly.

[0076] The fixing component is fitted onto the central tube 3 and has an upper end and a lower end. The lower end face of the fixing component contacts the upper end face of the rubber sleeve sealing component, and the fixing component is slidably connected to the central tube 3. During the setting and sealing installation, the fixing component is anchored to the well barrel by the anchoring device, that is, the fixing component does not undergo relative displacement with respect to the well barrel. Therefore, when the nozzle sleeve 13 applies an upward force to the rubber sleeve sealing component, the fixing component applies a downward force to the rubber sleeve sealing component.

[0077] Through the action of two forces, the rubber sleeve sealing assembly is compressed and expanded, increasing its diameter. When it is in a throttling state, the outer side of the rubber sleeve sealing assembly is compressed and seals against the inner side of the wellbore, thus achieving the purpose of sealing the downhole throttle with the wellbore.

[0078] Example 2

[0079] like Figure 2 As shown, after performing the sealing operation in Embodiment 1, it is necessary to separate the shock absorber from the central tube 3. Therefore, this embodiment provides a structure for the connecting assembly, which includes a release connector 1 and a pin shear sleeve.

[0080] The release connector 1 has an upper end and a lower end, and the upper end of the release connector 1 is connected to the shock absorber;

[0081] The pin shear sleeve 2 has a first inner hole section and a second inner hole section arranged coaxially. Whether the first inner hole section and the second inner hole section are connected or not is not affected. The lower end of the release connector 1 is set in the first inner hole section, and the release connector 1 is connected to the first inner control section by a thread.

[0082] The upper end of the central tube 3 is located inside the second inner bore section, and the central tube 3 is connected to the second inner bore section by a drop pin. That is, the outer surface of the pin shear sleeve 2 is provided with a pin hole that communicates with the second inner bore section, and the upper end of the central tube 3 is also provided with a corresponding pin hole. During the setting operation, the drop pin is inserted into the pin hole to connect the pin shear sleeve 2 and the central tube 3. After the setting is completed, the drop pin is subjected to a force exceeding its maximum shear stress by a shock device, thereby cutting off the drop pin and finally separating the pin shear sleeve 2 from the central tube 3. The connecting assembly is then pulled out of the well pipe, completing the setting.

[0083] The physical parameters of the drop pin can be calculated or tested by those skilled in the art using conventional techniques, and therefore do not constitute insufficient disclosure.

[0084] Example 3

[0085] like Figure 3 As shown, when discharging fluid, it is necessary to prevent sand from entering the central pipe 3. The sand prevention component in this embodiment includes a sand cover 15, a cut-and-fit metal tube 16, and a tail plug 17.

[0086] The sand shield 15 has an upper end and a lower end. The upper end of the sand shield 15 is sealed to the outer side of the mouth sleeve 13. The sand shield 15 is provided with multiple sand-proof through holes that penetrate inside and out.

[0087] The cut-and-seam gold tube 16 is fixedly installed inside the sandproof cover 15, and the cut-and-seam gold tube 16 has multiple slits that penetrate through the inside and outside.

[0088] The fluid undergoes a first layer of sand filtration through the sand shield 15, which isolates most of the sand and gravel outside the sand shield 15. The fluid undergoes a second layer of sand filtration through the cut-and-seamless tube 16, which filters the sand and gravel that pass through the sand shield 15 between the sand shield 15 and the cut-and-seamless tube 16, thereby achieving dual filtration and effectively preventing sand.

[0089] Therefore, it is necessary to ensure that the width of the cut metal tube 16 is smaller than the sandproof through hole of the sandproof cover 15.

[0090] In order to facilitate the emptying of sand and gravel between the sand shield 15 and the cut metal tube 16, the lower end of the sand shield 15 is set as an open structure for easy emptying. Therefore, a tail plug 17 that is easy to disassemble is required. It is sealed to the lower end of the sand shield 15 and can be easily removed and discharged when needed.

[0091] Example 4

[0092] like Figure 4 As shown, this embodiment describes the rubber sleeve sealing assembly in Embodiment 1. The rubber sleeve sealing assembly is the main sealing device and includes a rubber sleeve assembly.

[0093] The glue cartridge assembly is fitted onto the central tube 3, with its lower end face contacting the nozzle sleeve 13 and its upper end face contacting the fixing component.

[0094] In practical use, the central tube 3 applies an upward force to the nozzle sleeve 13, while ensuring that the position of the fixing component does not change. That is, the fixing component applies a downward force to the rubber sleeve assembly, which causes the rubber sleeve to expand and finally fit against the inner wall of the well barrel to achieve a seal.

[0095] In this embodiment, the rubber sleeve assembly can be a rubber sleeve 8, which is elastic.

[0096] Example 5

[0097] This embodiment describes a glue cartridge assembly, wherein the glue cartridge in this embodiment includes a seal.

[0098] Furthermore, the rubber sleeve sealing assembly also includes a sealing seat 12, which is disposed between the rubber sleeve assembly and the central tube 3 for auxiliary sealing. The sealing seat 12 includes a straight cylinder and a ring.

[0099] The straight sleeve is fitted onto the central tube 3, and the inner side of the straight sleeve slides and seals with the outer side of the central tube 3. The inner side of the upper end of the nozzle sleeve 13 slides and contacts the outer side of the lower end of the straight sleeve.

[0100] The circular ring is coaxially fitted onto the straight cylinder, and the inner ring surface of the circular ring is fixedly connected to the outer surface of the straight cylinder;

[0101] The straight cylinder and the ring can be a one-piece molded structure.

[0102] The glue cartridge assembly includes a first glue cartridge 11 and a second glue cartridge.

[0103] The first and second rubber tubes are both mounted on the straight cylinder and located on both sides of the ring. The lower end face of the fixing component is in contact with the upper end face of the first rubber tube 11, and the upper end face of the nozzle sleeve 13 is in contact with the lower end face of the second rubber tube.

[0104] By setting the rubber sleeve assembly into a two-section structure, the sealing effect is better, and the other rubber sleeve can still perform the sealing work normally if one rubber sleeve fails.

[0105] Example 6

[0106] After the rubber tube assembly in Embodiments 4 and 5 is compressed, if the distance between the fixing component and the nozzle 13 cannot be fixed, the seal will fail. Therefore, the sealing component in this embodiment also includes a back-locking and unsealing component, which is set between the rubber tube sealing component (rubber tube assembly) and the fixing component to maintain the distance between the fixing component and the nozzle 13 when sealing, and to prevent the distance from being maintained when unsealing.

[0107] like Figure 5 As shown, the anti-reverse unsealing assembly includes a sleeve 8, a C-ring 9, a shearing ring 10, and an unsealing pin 93.

[0108] The upper end of the sleeve 8 is connected to the fixing component, the inner side of the lower end of the sleeve 8 slides in contact with the outer side of the upper end of the straight cylinder, and an annular cavity is provided between the sleeve 8 and the central tube 3.

[0109] The inner surface of the C-ring 9 is provided with an inner ratchet 91, and the inner surface of the annular cavity is provided with an outer ratchet 92 that matches the inner ratchet 91; the angle between the deflection angle of the inner ratchet 91 and the upper end direction of the central tube 3 is an acute angle; the angle between the deflection angle of the outer ratchet 92 and the lower end direction of the central tube 3 is an acute angle.

[0110] The upper end face of the shear ring 10 contacts the lower end face of the C ring 9. The shear ring 10 is set in the annular cavity, and the outer side of the annular cavity is provided with a through pin hole. The outer side of the shear ring 10 is provided with a pin blind hole that matches the pin hole.

[0111] Unseal pin 93 passes through pin hole and connects with pin blind hole, and fixes shear ring 10 and sleeve 8.

[0112] Unsealing pin 93 fixes shear ring 10, while the lower end face of C ring 9 abuts against shear ring 10, so that shear ring 10 limits C ring 9, preventing it from moving down along central tube 3. By limiting the deflection angle of ratchet, central tube 3 can only move upward relative to C ring 9. That is, after central tube 3 is pulled up, it can no longer move down, thus playing a role in preventing backward movement.

[0113] When flow throttling is required, the fixing component is secured by the retrieval device, and then a downward force is applied to the central tube 3 by the shock absorber. At this time, because the C-ring 9 and the central tube 3 cannot undergo downward relative displacement, that is, the C-ring 9 and the central tube 3 move downward as a whole, and the C-ring 9 comes into contact with the shear ring 10. The C-ring 9 then applies a downward force to the shear ring 10, which is ultimately converted into the shear ring 10 applying a shearing force to the unsealing pin 93. When the shearing force does not exceed the shear stress limit of the shear pin, the shear ring 10, C-ring 9, central tube 3, sleeve 8, fixing component, nozzle 13, etc., do not change relative position and remain sealed.

[0114] When the shearing force exceeds the shear stress limit of the shear pin, the shear pin is sheared. At this time, the C ring 9 pushes the shear ring 10 downward, and the central tube 3 / nozzle 13 and the fixed component / sleeve 8 are relatively displaced. The distance between the fixed component and the nozzle 13 increases, and the rubber sleeve assembly is no longer squeezed and makes contact sealing.

[0115] Example 7

[0116] This embodiment describes the structure of the fixing component, which includes a fixing cylinder 4 and a locking slip 6.

[0117] The fixed cylinder 4 has a straight section and a tapered section. The lower end of the straight section is fixedly connected to the small diameter end of the tapered section, and the large diameter end of the tapered section is connected to the upper end of the sleeve 8.

[0118] The upper end of the slip 6 is fitted onto the straight section of the fixed cylinder 4, and the lower end of the slip 6 is attached to the outer side of the conical section of the fixed cylinder 4.

[0119] Among them, the conical section of the fixed cylinder 4 applies an outward force along the radial direction to the lower end of the slip 6.

[0120] During setting, the slips 6 are controlled to prevent relative displacement with the wellbore. When the central tube 3 moves upward, it drives the nozzle sleeve 13 to move upward. The nozzle sleeve 13 and the compression rubber sleeve sealing assembly then drive the sleeve 8 to move upward. The upward movement of the sleeve 8 drives the fixed cylinder 4 to move upward, thereby causing the conical section of the fixed cylinder 4 to apply an outward force to the lower end of the slips 6, making the lower diameter of the slips 6 larger until it abuts against the inner wall of the wellbore, thus fixing the slips 6 to the wellbore.

[0121] During the salvage operation, the shock absorber applies a downward force to the central tube 3, causing the anti-reverse unsealing component to unseal, the fixing cylinder 4 to move downward, and the lower diameter of the slip 6 to decrease, thus releasing the anchor.

[0122] In order to grasp the slip 6 during salvage or anchoring, the fixing component in this embodiment also includes a salvage neck 5. The salvage neck 5 is fixedly connected to the upper end of the slip 6 and can be connected to the salvage neck 5 during anchoring and salvage.

[0123] To achieve the function of Kava 6, Kava 6 in this embodiment includes an upper ring and tiles.

[0124] The upper ring is fitted onto the fixed cylinder 4, which can move up and down.

[0125] The tiles are arranged along the central axis of the fixing cylinder 4. The upper ends of multiple tiles are fixedly connected to the upper ring, and the lower ends of multiple tiles are attached to the conical section of the fixing cylinder 4. The upper ends of the tiles are fixed by clamps 7 to prevent their lower ends from detaching from the upper ring after being expanded by the fixing sleeve 4.

[0126] When in the throttling state, the lower outer side of the tile abuts against the inner side of the well shaft.

[0127] The tile has a certain degree of elasticity. By moving the fixed cylinder 4 upward, the lower end of the tile moves outward, thereby fixing it to the well cylinder. For stable fixing, serrations can be set on the outer side of the lower end of the tile.

[0128] In the description of this specification, the references to terms such as "one embodiment / mode," "some embodiments / modes," "example," "specific example," or "some examples," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment / mode or example is included in at least one embodiment / mode or example of this application. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment / mode or example. Moreover, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments / modes or examples. Furthermore, without contradiction, those skilled in the art can combine and integrate the different embodiments / modes or examples described in this specification, as well as the features of different embodiments / modes or examples.

[0129] 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 application, "multiple" means at least two, such as two, three, etc., unless otherwise explicitly specified.

[0130] Those skilled in the art should understand that the above embodiments are merely for illustrating the present invention and are not intended to limit the scope of the invention. Those skilled in the art can make other changes or modifications based on the above invention, and these changes or modifications still fall within the scope of the present invention.

Claims

1. A downhole choke for use in oil and gas production, the choke being arranged in a wellbore, c h a r a c t e r i s e d i n that include: Connection components; A central tube having an upper end and a lower end, the upper end of which is connected to the connecting assembly; A sand-proof component, which is connected to the lower end of the central tube; A sealing assembly having an upper end and a lower end, the sealing assembly being fitted onto the central tube, and the lower end of the sealing assembly being connected to the central tube, the sealing assembly comprising: a nozzle sleeve, a rubber sleeve sealing assembly, a fixing assembly, and a back-locking and release assembly; The lower end of the nozzle sleeve is connected to the lower end of the central tube, and a throttling nozzle for connecting the central tube and the sand control assembly is provided inside the nozzle sleeve; the rubber sleeve sealing assembly is fitted on the central tube, and the lower end face of the rubber sleeve sealing assembly contacts the upper end face of the nozzle sleeve; the fixing assembly is fitted on the central tube and has an upper end and a lower end, the lower end face of the fixing assembly contacts the upper end face of the rubber sleeve sealing assembly, and the fixing assembly is slidably connected to the central tube; wherein, in the throttling state, the outer surface of the rubber sleeve sealing assembly is sealed and fitted to the inner surface of the wellbore after being squeezed; the rubber sleeve assembly of the rubber sleeve sealing assembly is fitted on the central tube; the anti-reverse sealing assembly is disposed between the rubber sleeve sealing assembly and the fixing assembly; the anti-reverse sealing assembly includes: a sleeve, a C-ring, a shear ring, and a sealing pin; The upper end of the sleeve is connected to the fixing component, the inner side of the lower end of the sleeve slides in contact with the outer side of the upper end of the straight cylinder of the rubber sleeve sealing component, and an annular cavity is provided between the sleeve and the central tube. The inner surface of the C-ring is provided with an inner ratchet, and the inner surface of the annular cavity is provided with an outer ratchet adapted to the inner ratchet; the angle between the deflection angle of the inner ratchet and the upper end direction of the central tube is an acute angle; the angle between the deflection angle of the outer ratchet and the lower end direction of the central tube is an acute angle. The upper end face of the shearing ring contacts the lower end face of the C ring. The shearing ring is disposed in the annular cavity, and the outer side of the annular cavity is provided with a through pin hole. The outer side of the shearing ring is provided with a pin blind hole that matches the pin hole. The unsealing pin passes through the pin hole and connects to the pin blind hole, and fixes the shearing ring and the sleeve.

2. A downhole choke as claimed in claim 1, characterized in that The connection component includes: A release connector having an upper end and a lower end, the upper end of which is connected to a shock absorber; A pin-operated shear sleeve has a first inner hole section and a second inner hole section arranged coaxially. The lower end of the release connector is disposed in the first inner hole section and the release connector is threadedly connected to the first inner control section. The upper end of the central tube is disposed in the second inner hole section and the central tube is connected to the second inner hole section by a release pin.

3. A downhole choke as claimed in claim 1, characterized in that, The sand control component includes: A sand shield has an upper end and a lower end. The upper end of the sand shield is sealed to the outer side of the mouthpiece. The sand shield is provided with multiple sand-proof through holes that penetrate the inside and outside. A cut-and-seam gold tube is fixedly installed inside the sandproof cover, and the cut-and-seam gold tube has multiple slits that penetrate through the inside and outside. The tail plug is sealed to the lower end of the sand shield.

4. A downhole choke as defined by claim 1, wherein, The rubber sleeve sealing assembly also includes: A sealing seat is disposed between the rubber sleeve assembly and the central tube, the sealing seat comprising: A straight cylinder is fitted onto the central tube, and the inner side of the straight cylinder slides and seals with the outer side of the central tube, while the inner side of the upper end of the nozzle sleeve slides and contacts the outer side of the lower end of the straight cylinder. A circular ring is coaxially fitted onto the straight cylinder, and the inner ring surface of the circular ring is fixedly connected to the outer surface of the straight cylinder. The glue cartridge assembly includes: First glue tube; The second rubber tube, the first rubber tube and the second rubber tube are both fitted onto the straight cylinder and located on both sides of the ring. The lower end face of the fixing component is in contact with the upper end face of the first rubber tube, and the upper end face of the nozzle is in contact with the lower end face of the second rubber tube.

5. A downhole choke as defined by claim 1, wherein, The fixing component includes: A fixed cylinder has a straight section and a tapered section, the lower end of the straight section is fixedly connected to the small-diameter end of the tapered section, and the large-diameter end of the tapered section is connected to the upper end of the sleeve. The upper end of the slip is fitted onto the straight section of the fixed cylinder, and the lower end of the slip is attached to the outer side of the conical section of the fixed cylinder. The conical section of the fixed cylinder applies an outward force along the radial direction to the lower end of the slip.

6. A downhole choke as claimed in claim 5, characterised in that, The fixing component also includes a retrieval neck, which is fixedly connected to the upper end of the slip.

7. A downhole choke as defined in claim 5, wherein, The kava includes: The upper ring is fitted onto the fixed cylinder; The tiles are arranged along the central axis of the fixed cylinder, with the upper ends of the tiles fixedly connected to the upper ring and the lower ends of the tiles attached to the conical section of the fixed cylinder. When in a throttling state, the lower outer surface of the tile abuts against the inner surface of the well shaft.

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