Novel slip type underground throttler

Abstract

The invention discloses a novel slip type underground throttler which comprises an air inlet cylinder, an air tap, a locking nut, a seat sealing rubber sleeve, an end cover, a slip sliding seat, a slip, a slip fixing seat, a sealing cover, a fishing neck, a center rod and a throwing joint, and is characterized in that the center rod is an integral hollow rod, the throwing joint is arranged on the center rod, and the sealing cover is arranged on the throwing joint; the fishing neck is arranged on the outer side of the central rod in a sleeving manner; the slip fixing seat is provided with an occlusion structure used for holding and releasing the center rod, the center rod is sleeved with a reverse thrust spring, one end of the reverse thrust spring is arranged on the lower end face of the fishing rib, the other end of the reverse thrust spring is arranged on the inner end face of the end cover, and a spring supporting sleeve is arranged between the inner end face and the reverse thrust spring. The air inlet cylinder is detachably arranged at the bottom of the center rod.

Description

Technical Field

[0001] The present invention relates to the technical field of natural gas downhole throttling devices, and particularly to a novel slip type downhole throttler. Background Art

[0002] Traditional slip type downhole throttlers include a running head, a fishing head, a setting rubber seat, a sand control cover and an up-pulling tool. The running head is connected to the top of the fishing head through a shear pin. A positioning pin is arranged on the outer side of the lower end of the fishing head. The fishing head is slidably connected to a setting cylinder through a connecting sleeve. This type of slip type downhole throttler generally has a combined center rod, which includes an upper rod and a lower rod. The upper rod and the lower rod are combined together by threads. A middle sleeve is sleeved outside the center rod.

[0003] During the placement process, the placement tool is connected to the running head, and the throttler is placed in the natural gas well. The setting rubber sleeve contacts the well wall, and the slips support on the well wall to realize the setting of the throttler in the well wall. When releasing the seal, the fishing neck is lifted upwards, and the center rod is separated from the slip fixing seat along with the middle sleeve, releasing the compression force at the lower part of the slips to achieve the purpose of releasing the seal.

[0004] However, since there is no upward limit for the middle sleeve, it is easy to cause the top of the middle sleeve to be compressed and deformed during the placement and well opening processes. After the setting rubber sleeve is excessively compressed and deformed, the middle sleeve cannot effectively disengage from the slip fixing seat, resulting in the inability to release the setting rubber sleeve. Moreover, the acute angle where the slips bite the well pipe is an upward acting force, forming a relative force with the lower setting rubber sleeve. When the fishing neck is lifted upwards in the state where the setting rubber sleeve is not released, the setting rubber sleeve is opposite to the acute angle direction of the slips, making it difficult to lift. It is necessary to shock several times to disengage the slips from the well wall. However, if not careful during the shock process, the waist of the slips may break or the center rod may be bent and deformed. Once the slips break or the center rod is bent and deformed, the possibility of fishing out the throttler from the well is very slim.

[0005] During the experimental bench test of the traditional throttler, it is found that due to the lack of limit for the setting stroke after the pressure test, the phenomenon of the lip of the setting rubber sleeve turning outwards occurs, resulting in the edge of the rubber sleeve being squeezed into the gap between the throttler and the well pipe. After releasing the seal, the part squeezed into the gap presses against the slip support and cannot move downwards, causing difficulty in fishing. Summary of the Invention

[0006] The purpose of the present invention is to provide a novel slip type downhole throttler, which can solve the problem of difficult fishing of the existing slip type downhole throttler.

[0007] To achieve the above object, the technical solution adopted by the present invention is as follows: a novel slip-type downhole throttle, including an air inlet cylinder, a nozzle, a lock nut, a setting rubber sleeve, an end cap, a slip slide, slips, a slip fixing seat, a sealing cover, a fishing neck, a central rod, and a dropping joint. The central rod is an integral hollow rod. The dropping joint is installed on the central rod, and the fishing neck is sleeved outside the central rod. The slip fixing seat is provided with a biting structure for clamping and releasing the central rod. A reverse push spring is sleeved on the central rod. One end of the reverse push spring is placed on the lower end face of the fishing neck, and the other end is placed on the inner end face of the end cap. A spring support sleeve is provided between the inner end face and the reverse push spring. The air inlet cylinder is detachably arranged at the bottom of the central rod.

[0008] The solution adopted by the present invention changes the central rod to an integral structure, improving the strength of the central rod and reducing the middle casing structure at the same time. After setting, the top is lower than the top of the fishing neck, which can effectively avoid the fracture of the combined central rod during fishing or the bending deformation of the central rod caused by shock, improving the fishing efficiency and solving the problem that the downhole throttle cannot be fished out. A reverse push spring is added between the fishing neck and the sealing end cap. The reverse push spring and the fishing neck interact with each other. During dropping, it can prevent accidental setting due to the collision of well pipe interfaces and play a role in pushing down the slip slide during the unsealing process to facilitate the unsealing of the slips.

[0009] Further, the biting structure includes a pawl and a ratchet tooth. The pawl is hinged on the outer side wall of the slip fixing seat, and the ratchet tooth is arranged on the outer side wall of the central rod. The pawl and the ratchet tooth are engaged and matched. An annular groove is sleeved on the outer side wall of the slip fixing seat, and an annular spring for clamping the pawl is arranged in the annular groove.

[0010] The original hoop anti-back structure is improved to a ratchet mechanism, effectively avoiding the difficulty of unsealing caused by the deformation of the middle casing. Through the biting structure, the present invention can easily carry out the dropping and fishing work of the throttle, with simple operation, ensuring the complete removal of the throttle and allowing it to be reused.

[0011] Further, a rubber sleeve lining is provided between the setting rubber sleeve and the central tube, and three O-ring seals are provided between the rubber sleeve lining and the central rod.

[0012] The sealing rubber sleeve acts directly between the rubber sleeve lining and the well wall. The inner rubber sleeve moves up and down with the central rod, reducing the friction between the setting rubber sleeve and the central rod and facilitating the release of the setting rubber sleeve during the unsealing process. After the inner rubber sleeve moves up to a predetermined position inside the slip slide, the setting rubber sleeve is fully tightened with the inner wall of the well pipe and will not be deformed by secondary extrusion due to excessive pressure at the lower part of the throttle, and the rubber sleeve can quickly recover. The three O-ring seals can effectively avoid the phenomenon of air leakage during setting.

[0013] Furthermore, the slip fixing seat is provided with a through slot, and the ratchet claws are at least three and are evenly hinged on the inner side wall of the through slot of the slip fixing seat.

[0014] The three-pawl structure enables the pawl to effectively act on the ratchet part of the central pipe. The pawl supports the central pipe to move only in one direction upward. The elastic baffle can effectively prevent the pawl and the annular spring from being stretched outward and stuck in the well pipe.

[0015] The air nozzle is installed at the end of the air intake cylinder. The air nozzle is made of a material that is impact-resistant and wear-resistant. A blocking gasket is provided at the bottom of the air nozzle. Once the salvage fails, the air nozzle can be knocked down using a special tool. After being knocked down, the air nozzle falls into the bottom of the intake pipe to ensure normal air flow.

[0016] A stop gasket is provided at the end of the air intake cylinder and located on the outside of the center rod, a locking nut is provided at the other end of the stop gasket and located on the outside of the center rod, a seat sealing rubber sleeve is provided on the other side of the locking nut and located on the outside of the center rod, and a buffer gasket is provided on the other side of the seat sealing rubber sleeve and located on the outside of the center rod.

[0017] Furthermore, the end of the air intake cylinder is provided with an internal thread that matches the external thread of the center rod, and the center rod is provided with an external thread that matches the internal thread. The air intake cylinder is installed at the bottom of the center rod through threaded matching.

[0018] Before launching, the anti-retraction gasket is bent manually with the help of tools and applied to the air intake cylinder to hold the air intake cylinder tightly to prevent it from falling off and increase the firmness of the air intake cylinder. A blocking gasket is provided at the bottom of the air nozzle. If the salvage fails, the air nozzle can be knocked down with a special tool. After being knocked down, the air nozzle falls to the bottom of the intake pipe to ensure normal air flow.

[0019] The seat seal rubber sleeve should be made of rubber material with good sealing performance, high pressure resistance, corrosion resistance and aging resistance. When the throttle is released, the seat seal rubber sleeve is squeezed by lifting the center rod. When the throttle is about to reach the predetermined position, the release speed is increased and the release is stopped urgently. The throttle opens the slips and engages with the well wall through the inertia of falling. The center rod is slowly lifted. The three pairs of ratchets on the slip fixed seat are clamped by the annular spring. The ratchets can effectively act on the ratchet part of the center rod. The ratchets support the center rod and can only move upward in one direction. With the rise of the center rod, the slips and the inner wall of the well pipe are fully tightened. The seat seal rubber sleeve drives the inner sliding sleeve of the rubber sleeve to squeeze and expand upward through the center rod to achieve the purpose of seat sealing, which enhances the sealing performance of the seat seal rubber sleeve and the inner wall of the natural gas pipeline, and realizes effective sealing with the natural gas pipeline.

[0020] Furthermore, a groove-type guide slide is provided on the slip slide seat, one end of the slip is arranged on the slip fixing seat, and the other end is placed in the groove-type guide slide, and there are at least three slips.

[0021] After the throttler is placed in the appropriate position and then rapidly accelerated, immediately apply an emergency brake. Due to the inertia of the movement of the slip seat itself and the guiding effect of the guiding landslide, the slips will open to achieve the initial biting work on the inner side wall of the natural gas pipeline. By further lifting the central rod upward, the slips will be firmly engaged with the well pipe.

[0022] Furthermore, a releasing screw is provided between the slip retainer and the fishing neck, and the delivery joint is inserted on the central rod through a pin.

[0023] The fixing work of the fishing neck can be achieved through the releasing screw. When the throttler is taken out and inserted into the supporting fishing device to engage with the fishing neck, the releasing screw is cut off by lifting, causing the fishing neck to move upward, pushing the three pawls to open. There is a releasing spring inside the pawls. When the fishing neck opens the pawls, it will always be in the released state to prevent re-engagement. After the three pawls open, they will disengage from the central rod ratchet teeth. The central rod, through the acting force of the anti-pushing spring, disengages the slips and the seat sealing rubber sleeve from the well pipe, achieving the fishing work of the throttler. The delivery joint can achieve the fixing and delivery of the throttler by the delivery device, which is more convenient and reliable. Description of the Drawings

[0024] Figure 1 It is a schematic structural diagram of the slip-type downhole throttler of the present invention;

[0025] Figure 2 It is a schematic structural diagram before the assembly of the fishing neck, central rod and nozzle;

[0026] Figure 3 It is a schematic structural diagram before the assembly of the slip retainer, slip sleeve and slips;

[0027] Figure 4 It is a schematic structural diagram before the assembly of the slip sleeve, end cap and rubber inner lining sleeve;

[0028] Figure 5 For Figure 1 in, it is a schematic structural diagram of the unassembled structure on the left side of the end cap and end pipe;

[0029] Description of the reference numerals: 100, intake cylinder; 200, locking nut; 300, seat sealing rubber sleeve; 400, end cap; 500, slip seat; 600, slip retainer; 700, fishing neck; 800, central rod; 900, delivery head; 101, nozzle; 102, intake cylinder check washer; 210, buffer gasket; 510, slips; 601, pawl; 602, annular spring; 610, releasing structure; 611, releasing screw; 612, releasing spring; 620, sealing cover; 801, O-ring; 802, rubber inner lining sleeve; 803, anti-pushing spring; 804, spring support sleeve; 901, pin; 80, rubber inner sliding sleeve. Detailed implementation manners

[0030] For the purpose of making the objectives, technical solutions and advantages of the embodiments of the present invention clearer, the following will, with reference to the accompanying drawings of the embodiments of the present invention Figures 1 - 5 , clearly and completely describe the technical solutions of the embodiments of the present invention. Obviously, the described embodiments are only a part rather than all of the embodiments of the present invention. All other embodiments obtained by those of ordinary skill in the art based on the described embodiments of the present invention fall within the scope of protection of the present invention.

[0031] As Figures 1 - 5 shown: This embodiment provides a new type of slip-type downhole throttle, including an air inlet cylinder 100, a nozzle 101, a locking nut 200, a setting rubber sleeve 300, a slip slide 500, slips 510, a slip fixing seat 600, pawls 601, a fishing neck 700, a reverse push spring 803, a central rod 800, and a dropping joint 900. The air inlet cylinder 100 is detachably arranged at the bottom of the central rod 800. An end of the air inlet cylinder 100 is provided with an internal thread adapted to the external thread of the central rod 800. The central rod 800 is provided with an external thread adapted to the internal thread. The slip fixing seat 600 is provided with a biting structure for clamping and releasing the central rod 900. The biting structure includes at least three pawls 601 evenly and hingedly arranged on an outer side wall of the slip fixing seat 600. An outer side wall of the central rod 800 is provided with ratchet teeth engaged with the pawls 601. A through groove adapted to the pawls 601 is formed in the outer side wall of the slip fixing seat 600. An annular spring 802 for clamping the pawls 601 is sleeved on the outer side wall of the slip fixing seat 600. The present invention can realize the easy dropping and fishing operations of the throttle through the biting structure, with simple operation, ensuring the complete removal of the throttle and enabling repeated use.

[0032] There are three pawls 601, and they are evenly and hingedly arranged on an inner side wall of the through groove of the slip fixing seat 600.

[0033] The central rod 800 is an integral mechanism with a through hole in the middle. The bottom of the central rod 800 is threadedly connected to the intake cylinder 100. Inside the intake cylinder 100, there is a nozzle 101 for controlling the natural gas flow. The nozzle 101 should be made of a material with impact resistance and wear resistance. For example, in the prior art, cemented carbide or crystalline ceramics with high temperature resistance and high pressure resistance are selected. At the end of the intake cylinder 100 and outside the central rod 800, there is a retaining gasket 102 sleeved. Before placement, the operator bends the retaining gasket 102 with tools to act on the intake cylinder 100, clamping the intake cylinder 100 to prevent it from falling off and increasing the firmness of the intake cylinder 100. On the other side end of the retaining gasket 102 and outside the central rod 800, there is a lock nut 200. On the other side of the lock nut 200 and outside the central rod 800, there is a packoff rubber sleeve 300 sleeved. On the other side of the packoff rubber sleeve 300 and outside the central rod 800, there is a buffer gasket 210 sleeved. The packoff rubber sleeve 300 should be made of a rubber material with good sealing performance, high pressure resistance, corrosion resistance, and anti-aging performance. When the throttler is placed, the central rod 800 is lifted to squeeze the packoff rubber sleeve 300. When the throttler is about to reach the predetermined position, the placement speed is increased and then suddenly stopped. The throttler makes the slips open and bite with the wellbore wall due to the falling inertia. The central rod 800 is slowly lifted. There are three evenly distributed sets of pawls on the slips fixing seat 500. The outside of the pawls is held tightly by an annular spring 602, enabling the pawls to effectively act on the ratchet teeth 601 part of the central rod 800. The pawls support the central rod 800 to move only upward unidirectionally. As the central rod 800 rises, the slips are fully tightened against the inner wall of the well pipe. The packoff rubber sleeve 300 expands by extrusion to achieve the packoff purpose, enhancing the fitting and sealing performance between the packoff rubber sleeve 300 and the inner wall of the natural gas pipeline, and realizing effective sealing with the natural gas pipeline. On the other side of the buffer gasket 210 and outside the central rod 800, there is a biting assembly for biting with the inner wall of the downhole natural gas pipeline.

[0034] The biting assembly includes a slips sliding seat 500 sleeved outside the central rod 800. Inside the slips sliding seat 500 and outside the central rod 800, there is a spring support 804. Inside the spring support 804 and outside the central rod 800, there is a reverse spring 803 sleeved. At the end of the slips sliding seat 600, there is a guiding landslide. At least two slips 510 are provided outside the end of the slips fixing seat 600. In the present invention, through the biting assembly, when the throttler is placed and after it is quickly accelerated and then immediately braked when it reaches the appropriate position, due to the inertia of the movement of the slips sliding seat 500 itself and the guiding effect of the guiding landslide, the slips 510 will open to achieve the preliminary biting work on the inner wall of the natural gas pipeline. By further lifting the central rod 800 upward, the slips 510 are firmly bitten with the well pipe.

[0035] There are three slips 510, which are evenly arranged and clamped on the outer side wall of the end of the slip fixing seat 600.

[0036] A release nut 610 is screwed on the fishing neck. On the outer side wall of the slip fixing seat 600, a release screw 611 is provided, and the fixing work of the fishing neck 700 can be realized through the release screw 611.

[0037] After the throttler is taken out and the matching fishing device is put in, the release screw 611 is cut off by lifting, so that the fishing neck 700 moves upward to push the three pawls to open. When the three pawls open, they are disengaged from the ratchet teeth of the central rod 800. The central rod 800 separates the slip 510 and the seat sealing rubber sleeve 300 from the well pipe through the acting force of the anti-push spring 803, realizing the fishing work of the throttler.

[0038] On the outer side of the end of the central rod 800, a fishing neck 900 for fishing the throttler is provided. On the axis of the end of the central rod 800, a delivery joint 900 is detachably arranged. The delivery joint 900 is inserted on the central rod 800 through a pin 901. Through the delivery joint 900, the fixing and delivery of the throttler by the delivery device can be realized, which is more convenient and reliable.

[0039] The assembly and use method of the present invention:

[0040] First of all, it should be clear that the throttler involved in the present invention is used for throttling and reducing the pressure of natural gas in various natural gas underground pipelines, which can prevent the occurrence of hydrate blockage at the wellhead, thus making the transportation of natural gas safer and greatly reducing the production cost. When the throttler needs to be delivered, the assembly work of the throttler needs to be carried out first.

[0041] Assembly process: Step 1, assemble three pawls on the slip fixing seat 600;

[0042] Step 2, insert the fishing neck 700 into the inside of the slip fixing seat 600, make the three openings on the fishing neck 600 correspond to the pawls, and install the release screw 611;

[0043] Step 3, assemble the slip 510 with the slip slide 500 and the slip fixing seat 600;

[0044] Step 4, connect the central rod 800 and the delivery joint 900 with a pin 901;

[0045] Step 5, insert the central rod 800 from the upper part of the fishing neck 700, push the anti-push spring into the inside of the slip slide 600 from the small end of the central rod 800, install the anti-push spring support 804 and fix it with a fastening screw, and install the slip slide 500 and the end cover 400;

[0046] Step 6: Install two seat sealing rubber sleeves 300 and buffer washers 210 in sequence, and install the locking nut 200 and the stop washers 210 on the center rod 800;

[0047] Step 7: Install the air nozzle 110 inside the small end of the center rod 600, install the air inlet cylinder 100, and bend the stop gasket 102 onto the end surfaces of both sides of the air inlet cylinder 100;

[0048] Step 8: Clamp the annular spring 602 into the three ratchet grooves to complete the installation.

[0049] Working principle of throttle:

[0050] Release: connect the throttle to the tool string and release it (the tool string includes a rope cap, a counterweight rod, and a jar). When the throttle is about to reach the predetermined position, increase the release speed and stop the release urgently. The throttle opens the slips and engages with the well wall through the inertia of falling, and slowly lifts the center rod (there are three pairs of pawls evenly distributed on the throttle slip fixing seat, and the outside of the pawls is clamped by an annular spring 803, so that the pawls can effectively act on the ratchet part of the center rod. The pawls support the center rod and can only move upward in one direction). As the center rod rises, the slips and the inner wall of the well pipe are fully tightened. When the lifting tension reaches 350KG, the sealing rubber sleeve is squeezed and expanded to achieve the sealing purpose. The jar of the tool string is released to jar upward, and the release pin is cut off, and the throttle is sealed.

[0051] Salvage: Select a salvage tool string that matches the throttle model (the tool string includes a rope cap, a counterweight rod, a jar, and a salvage tube), use the delivery tool string to connect and drop into the well. When the salvage tube is combined with the throttle salvage neck, lift the salvage tube to cut off the unsealing screw, and the salvage sleeve drives the salvage neck upward to push open the three pawls. The reverse spring pushes the center rod downward, and the center rod drives the slip slide downward to unseal the slip. After the center rod moves down to its position, the sealing sleeve is automatically unsealed, and the throttle is lifted out to complete the salvage.

[0052] If it is difficult to lift up after unsealing, it is mostly because the teeth of the slip are embedded in the well pipe. A jar can be used to jar the slip upward to separate it from the well wall.

[0053] The present invention has a throttle with a built-in ratchet structure, which is convenient for dropping and salvaging, simple to operate, does not require shocking, and ensures that it can be taken out intact and can be reused.

[0054] Compared with the traditional slip throttle, the scheme adopted by this new model has the following advantages:

[0055] 1. Change the central tube to an integral type to avoid the salvage fracture accident caused by the original multi-section combination;

[0056] 2. The original clamp stop structure is improved to a ratchet mechanism, which effectively avoids the difficulty of unsealing caused by deformation of the middle casing;

[0057] 3. The sealing rubber sleeve acts directly between the rubber sleeve lining and the wellbore wall. The inner lining pipe moves up and down with the central rod, facilitating the quick restoration of the rubber sleeve and effectively avoiding the phenomenon of seat leakage.

[0058] 4. A separation gasket is provided at the lower part of the air nozzle. In case of fishing failure, the air nozzle can be knocked down. After being knocked down, it will fall to the bottom of the intake pipe to ensure normal gas passage.

[0059] 5. An elastic retaining piece is designed outside the ratchet teeth to prevent the ratchet pawl and the annular spring from expanding outward and getting stuck in the well pipe.

[0060] In addition, it should be noted that in the description of the present invention, unless otherwise clearly defined and limited, the terms "installation", "connection", and "coupling" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be directly connected or indirectly connected through an intermediate medium, and it can be the communication inside two components. For those skilled in the art, the specific meanings of the above terms in the present invention can be understood according to specific situations.

[0061] The above is the preferred embodiment of the present invention. It should be pointed out that for those of ordinary skill in the art, without departing from the principle of the present invention, several improvements and refinements can be made, and these improvements and refinements should also be regarded as the protection scope of the present invention.

Claims

1. A new type of slip-type downhole choke, including an air inlet tube, an air nozzle, a locking nut, a seat sealing rubber sleeve, an end cover, a slip sliding seat, a slip, a slip fixing seat, a sealing cover, a fishing neck, a center rod, and a launching joint, characterized in that: The center rod is an integral hollow rod, the launching joint is installed on the center rod, and the salvage neck sleeve is arranged on the outside of the center rod; the cava fixing seat is provided with a bite structure for clamping and releasing the center rod, and a reverse thrust spring is installed on the center rod, one end of the reverse thrust spring is placed on the lower end face of the salvage force, and the other end is placed on the inner end face of the end cover, and a spring support sleeve is provided between the inner end face and the reverse thrust spring; the air intake cylinder is detachably arranged at the bottom of the center rod.

2. A novel slip-type downhole choke according to claim 1, characterized in that: The engaging structure includes a pawl and a ratchet, the pawl is hinged on the outer wall of the slip fixing seat, and the ratchet is arranged on the outer wall of the center rod, and the pawl and the ratchet are engaged with each other; an annular groove is sleeved on the outer wall of the slip fixing seat, and an annular spring is arranged in the annular groove for the pawl to clamp.

3. A novel slip-type downhole choke according to claim 2, characterized in that: The slip fixing seat is provided with a through slot, and the number of the ratchet claws is at least 3 and they are evenly hinged on the inner side wall of the through slot of the slip fixing seat.

4. A novel slip-type downhole choke according to claim 1, characterized in that: A rubber sleeve inner liner is arranged between the seat sealing rubber sleeve and the central tube, and three O-type sealing rings are arranged between the rubber sleeve inner liner and the central rod.

5. A novel slip-type downhole choke according to claim 3 or 4, characterized in that: An elastic blocking piece is arranged outside the ratchet.

6. A novel slip-type downhole choke according to claim 1, characterized in that: The air nozzle is installed at the end of the air intake cylinder, and a back-stop gasket is sleeved at the end of the air intake cylinder and located on the outside of the center rod, a locking nut is provided at the other end of the back-stop gasket and located on the outside of the center rod, a seat sealing rubber sleeve is sleeved on the other side of the locking nut and located on the outside of the center rod, and a buffer gasket is sleeved on the other side of the seat sealing rubber sleeve and located on the outside of the center rod.

7. A novel slip-type downhole choke according to claim 1, characterized in that: The end of the air intake cylinder is provided with an internal thread matched with the external thread of the center rod, the center rod is provided with an external thread matched with the internal thread, and the air intake cylinder is installed at the bottom of the center rod through thread matching.

8. A novel slip-type downhole choke according to claim 1, characterized in that: A groove-type guide slide is provided on the slip slide seat, one end of the slip is arranged on the slip fixing seat, and the other end is placed in the groove-type guide slide, and there are at least three slips.

9. A novel slip-type downhole choke according to claim 1, characterized in that: An unsealing screw is arranged between the slip fixing seat and the salvage force, and the launching joint is inserted on the central rod through a pin.

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