Slip type underground throttler

Abstract

The utility model discloses a slip type underground throttler, and relates to the technical field of oil and gas field exploitation equipment. The slip type downhole throttler comprises a main body pipe, a slip anchoring assembly arranged on the outer wall of the main body pipe, a rubber sleeve sealing assembly located above the slip anchoring assembly, a throttling channel penetrating through the main body pipe and a fishing connecting structure arranged at the top end of the main body pipe. The slip anchoring assembly comprises at least three slip pieces distributed in the circumferential direction, and the rubber sleeve sealing assembly is made of elastic sealing materials and arranged outside the main body pipe in a sleeving mode. The slip type downhole throttling device is used for solving the technical problems that an existing downhole throttling device is prone to setting midway in the throwing process, slip anchoring is not firm, rubber sleeve sealing fails, fishing is difficult, and corrosion resistance is poor.

Description

Technical Field

[0001] This utility model relates to the field of oil and gas field development equipment technology, and in particular to a slip-type downhole throttle. Background Technology

[0002] In gas field development, downhole choke technology is a crucial means of controlling the production pressure differential and stabilizing gas well output. Currently, most downhole chokes on the market employ a slip-type structure, securing the choke to the inner wall of the tubing via slips. However, existing slip-type downhole chokes present several technical problems in practical applications: for example, during deployment, the presence of hydrates, gum, or other foreign matter within the wellbore, or the accumulation of fracturing sand, wax, or scale on the inner wall of the tubing, can easily cause the choke to set prematurely before reaching the intended position, affecting the accuracy and reliability of downhole choke operations; furthermore, design flaws in the slip anchoring structure lead to insecure anchoring, or insufficient sealing performance and durability of the rubber sleeve sealing components. Summary of the Invention

[0003] The purpose of this utility model is to provide a slip-type downhole choke to solve the technical problems of existing downhole chokes, such as easy mid-way sealing during deployment, unstable slip anchoring, failure of rubber sleeve seal, difficulty in retrieval, and poor corrosion resistance.

[0004] To achieve the above objectives, this utility model provides the following technical solution: a slip-type downhole throttling system, comprising a main pipe, a slip anchoring assembly disposed on the outer wall of the main pipe, a rubber sleeve sealing assembly located above the slip anchoring assembly, a throttling channel penetrating the main pipe, and a retrieval connection structure disposed at the top of the main pipe; the slip anchoring assembly comprises at least three circumferentially distributed slips, and the rubber sleeve sealing assembly is made of elastic sealing material and fitted onto the outside of the main pipe.

[0005] Optionally, the slip anchoring assembly further includes a setting drive mechanism for driving the radial expansion of the slip, the setting drive mechanism being linked with a release pin structure inside the main tube. Through the linkage design of the setting drive mechanism and the release pin, accurate setting and release of the throttle at a predetermined position is achieved, avoiding the problem of mid-way setting.

[0006] Optionally, the outer surface of the slip is provided with anti-slip anchoring teeth, the teeth of which are continuously serrated along the circumference of the slip. This serrated anti-slip anchoring tooth design increases the contact area and friction between the slip and the inner wall of the tubing, ensuring firm anchoring even on uneven inner walls or with slight scaling, effectively solving the problem of slips failing to stay in place.

[0007] Optionally, the rubber sleeve sealing assembly includes multiple layers of hydrogenated nitrile butadiene rubber (NBR), with the inner side of each NBR tightly fitted to the outer wall of the main tube and the outer side forming a sealing surface that contacts the inner wall of the tubing. This multi-layered NBR design not only improves the elasticity and sealing performance of the rubber sleeve but also enhances its corrosion resistance and aging resistance, enabling it to maintain a good sealing condition for a long time in complex downhole media environments.

[0008] Optionally, a detachable throttling nozzle assembly is provided within the throttling channel. The throttling nozzle assembly is fixed to the main tube by a threaded connection or snap-fit. This detachable throttling nozzle assembly design allows operators to easily replace throttling nozzles of different inner diameters according to the production needs of the gas well, achieving precise control over gas well production and improving the applicability and flexibility of the throttling device.

[0009] Optionally, the retrieval connection structure is a convex annular retrieval head, the outer periphery of which is provided with a groove or protrusion that mates with the retrieval tool. This structural design facilitates the retrieval tool's accurate capture of the retrieval head. Through the cooperation between the retrieval tool and the groove or protrusion, the retrieval pull force can be reliably transmitted, ensuring the smooth retrieval of the throttle and avoiding retrieval difficulties caused by an unreasonable retrieval head structure design.

[0010] Optionally, the outer wall of the main tube is provided with an anti-mid-course setting protective sleeve, which can restrict the radial movement of the slips during the deployment of the throttle. The anti-mid-course setting protective sleeve restrains the slips during the throttle's lowering process. The protective sleeve is only removed or becomes ineffective when the throttle reaches the predetermined position and performs the setting operation, thereby effectively preventing the slips from opening prematurely due to external interference during deployment and ensuring the accurate deployment of the throttle.

[0011] Optionally, the main tube and slips are made of a corrosion-resistant alloy, and the surface of the corrosion-resistant alloy is coated with an acid- and alkali-resistant protective coating. This dual protection of the corrosion-resistant alloy and the protective coating enables the choke to operate stably in well conditions containing corrosive media such as hydrogen sulfide and carbon dioxide, extending the choke's service life, reducing replacement frequency, and lowering operating costs.

[0012] Compared with existing technologies, the slip-type downhole choke provided by this utility model features continuously serrated anti-slip anchoring teeth on the outer surface of the slips, which increase the friction and contact area with the inner wall of the tubing, solving the problem of unstable anchoring of existing slips and ensuring stable operation of the choke downhole. The multi-layered hydrogenated nitrile rubber sleeve sealing assembly has good elasticity, corrosion resistance, and aging resistance, maintaining a long-term effective seal and preventing leakage due to sleeve failure. The anti-mid-seating protective sleeve effectively prevents leakage caused by foreign objects in the wellbore or the tubing wall. The mid-way setting caused by scaling and other factors improves the accuracy and reliability of choke deployment; the annular retrieval head, with its groove or ridge structure, facilitates accurate capture and application of retrieval force by the retrieval tool, avoiding downhole accidents caused by retrieval difficulties and reducing the difficulty and cost of well workover operations; the main tube and slips are made of corrosion-resistant alloy material with a protective coating, which can effectively resist corrosion from downhole acidic gases, condensate oil, and hydrogen sulfide-containing media, extending the service life of the choke, reducing the number of replacements, and improving the continuity and economy of gas well production. Attached Figure Description

[0013] Figure 1 A schematic diagram of the structure of the slip-type downhole throttle provided in this embodiment of the utility model.

[0014] Figure 2 for Figure 1 Schematic diagram at point A in the middle.

[0015] Reference numerals: 100-Throttle; 1-Main tube; 2-Slip anchoring assembly; 21-Slip plate; 3-Rubber sleeve sealing assembly; 31-Rubber sleeve; 4-Retrieval head; 5-Release pin structure; 51-Unsealing ring; 52-Unsealing pin; 6-Throttle nozzle assembly; 61-Nozzle; 62-Nozzle sleeve. Detailed Implementation

[0016] To make the technical problems, technical solutions, and beneficial effects of this utility model clearer, the present utility model 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 merely illustrative of the present utility model and are not intended to limit the present utility model.

[0017] It should be noted that when a component is referred to as being "fixed to" or "set on" another component, it can be directly on or indirectly on that other component. When a component is referred to as being "connected to" another component, it can be directly connected to or indirectly connected to that other component.

[0018] 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 indicated technical features. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this utility model, "a plurality of" means two or more, unless otherwise explicitly specified. "Several" means one or more, unless otherwise explicitly specified.

[0019] In the description of this utility model, it should be understood that the terms "upper", "lower", "front", "rear", "left", "right", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this utility model and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this utility model.

[0020] In the description of this utility model, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "joining" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in this utility model according to the specific circumstances.

[0021] Please see Figure 1 and Figure 2 The slip-type downhole choke 100 provided in this embodiment of the utility model has a tubular structure and mainly consists of a main tube 1, a slip anchoring assembly 2, a rubber sleeve sealing assembly 3, a choke channel, and a retrieval connection structure. The main tube 1, as the basic support component of the choke 100, is made of corrosion-resistant alloy material, and a through choke channel is formed inside it. The slip anchoring assembly 2 and the rubber sleeve sealing assembly 3 are installed on the outside.

[0022] The slip anchoring assembly 2 is disposed on the lower middle outer wall of the main tube 1, and includes three circumferentially evenly distributed slips 21 (in other embodiments, the number of slips 21 may be four or more depending on actual needs). Each slip 21 is connected to the main tube 1 via a hinge structure or sliding groove, and can expand or contract radially under the action of the seat drive mechanism. The outer surface of the slip 21 is machined with continuous serrated anti-slip anchoring teeth. This tooth design can increase the friction with the inner wall of the tubing and improve the reliability of anchoring.

[0023] The sealing drive mechanism is located inside the main tube 1 and connected to the inner side of the slip 21. When the throttle 100 is lowered to a predetermined depth, the sealing drive mechanism is pulled upward by lifting the wire rope, which pushes the slip 21 to expand radially, making the anti-slip anchoring teeth tightly contact the inner wall of the tubing, thus achieving anchoring. The sealing drive mechanism is linked with the release pin structure 5 inside the main tube 1. The release pin structure 5 includes a release pin 52 and a release ring 51. After anchoring is completed, the wire rope is continued to be lifted. When the tension reaches a certain value, the release pin is sheared, the sealing drive mechanism separates from the main tube 1, and the throttle 100 is released and suspended on the inner wall of the tubing.

[0024] The rubber sleeve sealing assembly 3 is located above the slip anchoring assembly 2 and is fitted onto the outer wall of the main tube 1. This assembly is composed of multiple layers of hydrogenated nitrile rubber. The inner side of each rubber layer is tightly fitted to the outer wall of the main tube 1 through an interference fit, while the outer side forms a smooth sealing surface that contacts the inner wall of the tubing. The multi-layer rubber design not only improves the elasticity of the rubber sleeve 31, allowing it to fully deform and form a seal when squeezed by the inner wall of the tubing, but also enhances its corrosion resistance and aging resistance, enabling it to adapt to downhole environments containing corrosive media such as hydrogen sulfide and carbon dioxide.

[0025] During the sealing process of the slip anchoring assembly 2, the rubber sleeve sealing assembly 3 is compressed and expands radially, further filling the gap between the main tube 1 and the inner wall of the oil pipe, forming a reliable seal to prevent gas from leaking from the gap between the throttle 100 and the oil pipe.

[0026] The throttling channel passes through the axis of the main body tube 1, extending from the bottom to the top. A throttling nozzle mounting cavity is provided in the middle or lower part of the throttling channel, and a detachable throttling nozzle assembly 6 is installed in the mounting cavity. The outer periphery of the throttling nozzle assembly 6 is provided with external threads, which mate with the internal threads on the inner wall of the mounting cavity to achieve threaded connection and fixation (in other embodiments, a snap-fit ​​method can also be used, such as providing a slot and a block for engagement).

[0027] Workers can select throttle nozzle assemblies 6 with different inner diameters and install them in the throttle channel according to the production needs of the gas well. The throttle nozzle assembly 6 includes a nozzle 61 and a nozzle sleeve 62 that cooperate with each other. When it is necessary to adjust the gas well production, the throttle device 100 can be retrieved with a retrieval tool, the throttle nozzle assembly 6 can be replaced, and then it can be re-deployed, so as to achieve flexible adjustment of the throttle size and thus accurately control the production pressure difference and production of the gas well.

[0028] The retrieval connection structure is located at the top of the main tube 1 and is an outwardly protruding annular retrieval head 4. The outer circumference of the annular retrieval head 4 is machined with a groove or protrusion that mates with the retrieval tool. When it is necessary to retrieve the throttle 100, a special retrieval tool is lowered in. The front end of the retrieval tool is provided with a claw or groove that matches the groove or protrusion. By lowering and raising the retrieval tool, the claw or groove engages with the groove or protrusion, thereby capturing the retrieval head 4.

[0029] To prevent the throttle 100 from sealing midway during deployment, a protective sleeve against midway sealing is provided on the outer wall of the main tube 1, outside the slip anchoring assembly 2. The protective sleeve is cylindrical and fitted over the main tube 1. Its inner diameter is slightly larger than the outer diameter of the slip 21 in its contracted state, and its outer diameter is smaller than the inner diameter of the oil pipe, so as to facilitate smooth lowering within the oil pipe.

[0030] During the deployment of the throttle 100, the anti-mid-seating protective sleeve constrains the slips 21, limiting their radial movement. Even if foreign objects or scale buildup on the pipe wall are encountered in the wellbore, the slips 21 will not open prematurely, thus effectively preventing mid-seating. When the throttle 100 reaches the predetermined depth and performs the setting operation, the anti-mid-seating protective sleeve is pushed upward or detached from the main pipe 1 by the pulling force of the lifting wire rope, releasing the constraint on the slips 21 and allowing the slips 21 to expand radially normally to achieve setting.

[0031] In practice: The choke 100 is connected to the deployment tool string, which includes a rope cap, a weighted rod, a mechanical shock absorber, and a setting tool. The deployment tool string and choke 100 are lowered into the gas well, which has already been installed in the production tubing, via a logging wire rope. During the lowering process, an anti-mid-set protective sleeve restricts the radial movement of the slips 21 to prevent mid-way setting. Once the predetermined depth is reached, lowering is stopped and the tool string is then pulled back up. The tool string is then lowered rapidly and braked sharply, causing the slips 21 on the choke 100 to expand radially under the action of the setting drive mechanism, achieving initial setting. The wire rope is then slowly pulled up. When the load on the wire rope exceeds a certain value of the tension before setting, it indicates that the plug has successfully started setting. The tool string is then pulled up further. When the tension reaches the shear force of the release pin, the release pin shears, separating the setting tool from the choke 100. The choke 100 is then suspended at a fixed depth on the inner wall of the tubing, completing the deployment.

[0032] During well production, the high-pressure gas in the lower part is controlled to be produced to the surface through the throttling nozzle assembly 6 in the throttling channel, thereby achieving the purpose of throttling production and controlling the production pressure difference. Due to the firm anchoring of the slip anchoring assembly 2 and the reliable sealing of the rubber sleeve sealing assembly 3, the stability and sealing performance of the throttling device 100 are ensured during operation.

[0033] When maintenance or replacement of the throttle nozzle is required, a retrieval tool string is lowered. This string includes a rope cap, a weighted rod, a vibrator, and a retractable spring-loaded retrieval tool. The retrieval tool string is lowered to the position of the throttle nozzle 100, the tubing is lifted, and the retrieval head 4 of the throttle nozzle 100 is quickly lowered to impact and capture it. The string is then slowly lifted; when the load increases to a certain value, it indicates that the retrieval tool has captured the retrieval head 4. The tool string is then lowered back to its original suspension weight, and the retrieval tool is quickly lifted, using the vibrator to impact and release the throttle nozzle 100's locking mechanism, causing the rubber sleeve 31 to reset. Finally, the retrieval tool string is lifted to retrieve the throttle nozzle 100 from the ground.

[0034] As can be seen from the structure and specific implementation process of the slip-type downhole choke 100 described above, the continuous serrated anti-slip anchoring teeth on the outer surface of the slip 21 increase the friction and contact area with the inner wall of the tubing, achieving firm anchoring even when the inner wall of the tubing is uneven. This solves the problem of unstable anchoring of existing slips and ensures stable operation of the choke 100 downhole. The rubber sleeve sealing assembly 3, made of multi-layer hydrogenated nitrile rubber, has good elasticity, corrosion resistance, and aging resistance, and can maintain a long-term effective seal in complex downhole pressure and media environments, avoiding leakage of the choke 100 due to failure of the rubber sleeve 31. The anti-mid-seating protective sleeve restrains the slip 21 during the deployment of the choke 100, effectively preventing mid-seating caused by foreign objects in the wellbore or scaling on the pipe wall, thus improving the accuracy and reliability of the choke 100 deployment. The annular retrieval head 4, with its grooved or protruding ridge design, facilitates accurate capture and application of retrieval force by the retrieval tool. Combined with a well-designed setting and release mechanism, it allows the choke 100 to be smoothly released during retrieval, preventing downhole accidents caused by retrieval difficulties and reducing the difficulty and cost of well workover operations. The main tube 1 and slips 21 are made of corrosion-resistant alloy material with a protective coating, effectively resisting corrosion from downhole acidic gases, condensate oil, and hydrogen sulfide-containing media. This extends the service life of the choke 100, reduces replacement frequency, and improves the continuity and economy of gas well production.

[0035] In the description of the above embodiments, specific features, structures, materials, or characteristics may be combined in any suitable manner in one or more embodiments or examples.

[0036] The above description is merely a specific embodiment of this utility model, but the protection scope of this utility model is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in this utility model should be included within the protection scope of this utility model. Therefore, the protection scope of this utility model should be determined by the protection scope of the claims.

Claims

1. A slip-type downhole choke, characterized in that, The device includes a main tube, a slip anchoring assembly disposed on the outer wall of the main tube, a rubber sleeve sealing assembly located above the slip anchoring assembly, a throttling channel penetrating the main tube, and a retrieval connection structure disposed at the top of the main tube; the slip anchoring assembly includes at least three circumferentially distributed slips, and the rubber sleeve sealing assembly is made of elastic sealing material and is fitted onto the outside of the main tube.

2. The slip-type downhole choke according to claim 1, characterized in that, The slip anchoring assembly also includes a seat sealing drive mechanism for driving the slip to expand radially, and the seat sealing drive mechanism is linked to the release pin structure inside the main tube.

3. The slip-type downhole choke according to claim 2, characterized in that, The outer surface of the slip is provided with anti-slip anchoring teeth, and the teeth of the anti-slip anchoring teeth are distributed in a continuous sawtooth pattern along the circumference of the slip.

4. The slip-type downhole choke according to claim 1, characterized in that, The rubber sleeve sealing assembly includes multiple layers of hydrogenated nitrile butadiene rubber stacked together. The inner side of the hydrogenated nitrile butadiene rubber layer is tightly fitted to the outer wall of the main tube, and the outer side forms a sealing surface that contacts the inner wall of the oil pipe.

5. The slip-type downhole choke according to claim 1, characterized in that, A detachable throttling nozzle assembly is provided inside the throttling channel, and the throttling nozzle assembly is fixed inside the main tube by threaded connection or snap-fit.

6. The slip-type downhole choke according to claim 1, characterized in that, The salvage connection structure is an outwardly convex annular salvage head, and the outer periphery of the annular salvage head is provided with a groove or protruding ridge structure that cooperates with the salvage tool.

7. The slip-type downhole choke according to any one of claims 1-6, characterized in that, The outer wall of the main tube is provided with an anti-mid-course sealing protective sleeve, which can restrict the radial movement of the slip plate during the deployment of the throttle.

8. The slip-type downhole choke according to claim 7, characterized in that, The main tube and the slip plate are made of corrosion-resistant alloy, and the surface of the corrosion-resistant alloy is provided with a protective coating that is resistant to acids and alkalis.

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