Wear-resistant downhole throttler

Abstract

The invention relates to the technical field of downhole throttlers, and discloses a wear-resistant downhole throttler which comprises an outer sleeve, a central pipe is coaxially fixed in the outer sleeve, a plurality of air outlets are formed in the lower side of the central pipe at equal angles, and a first piston coaxial with the central pipe is slidably connected into the central pipe; a throttling ring is arranged under the first piston and used for achieving the effect of adjusting the opening size of the air outlet. According to the wear-resistant downhole throttler, the regulation and control mechanism is adopted, automatic locking of the first piston can be achieved when the air pressure in a pipeline changes slightly in the using process of the device, and therefore automatic locking of the position of the throttling ring is achieved, frequent slight action generated by the throttling ring when the air pressure fluctuation amplitude is small is avoided, the service life of the throttling ring is prolonged, and the service life of the throttling ring is prolonged. When the air pressure change in the pipeline is large, the first piston can be automatically unlocked, so that the position of the throttling ring is adjusted, and the stability of the flow in the pipeline is ensured.

Description

Technical Field

[0001] This invention relates to the field of downhole choke technology, specifically a wear-resistant downhole choke. Background Technology

[0002] Downhole chokes are key tools used in oil and gas field development to control fluid flow within the wellbore. Their main functions are to control fluid flow, stabilize wellhead pressure, and prevent hydrate formation. They are widely used, especially in natural gas wells. Existing downhole throttling devices, such as the one disclosed in CN106285580B, include a housing with an outlet, an inlet on the housing, and a gas channel connecting the inlet and outlet. A floating throttling element, capable of floating according to the inlet pressure and having a throttling chamber, is floating within the housing. The gas channel includes a first channel disposed on the housing along a direction perpendicular to the floating throttling element and a second channel disposed on the floating throttling element and connected to the throttling chamber. The first and second channels are opposite to and connected. When the floating throttling element is not floating, the connection area between the first and second channels is at its maximum. When the gas pressure increases, the floating throttling element can float to reduce the connection area between the first and second channels, achieving throttling and pressure reduction, thus reducing hydrate formation. When the gas pressure decreases, the floating throttling element floats to increase the connection area between the first and second channels, ensuring its flow rate. While the existing downhole throttles can automatically regulate the flow rate in the pipeline by changing fluid pressure, in actual use, the underground natural gas pressure changes in real time. This causes the throttle element to move regardless of whether the pressure fluctuation is large or small. As a result, the throttle element has poor adaptability to pressure fluctuations. Furthermore, when the throttle element moves frequently due to small pressure fluctuations, it will accelerate the wear of the throttle element and affect the service life of the device. Summary of the Invention

[0003] The purpose of this invention is to provide a wear-resistant downhole choke to solve the problems mentioned in the background art.

[0004] To achieve the above objectives, the present invention provides the following technical solution: a wear-resistant downhole throttle, comprising an outer casing, a central tube fixed coaxially inside the outer casing, a plurality of air outlets being opened at equal angles on the lower side of the central tube, a first piston slidably connected coaxially inside the central tube, and a throttle ring being provided directly below the first piston for adjusting the size of the air outlet openings. An auxiliary positioning mechanism is used to guide and position the outer cover during installation, preventing it from shaking. The auxiliary positioning mechanism is installed on the upper side of the outer cover. The control mechanism utilizes air pressure changes to achieve the self-locking and unlocking function of the first piston, reducing the micro-floating friction of the throttling ring. The control mechanism is connected to the first piston and is located inside the central tube.

[0005] Preferably, the auxiliary positioning mechanism includes a threaded sleeve that is threadedly connected to the air outlet pipe, and the threaded sleeve and the connecting ring are slidably connected, and the connecting ring and the air outlet pipe are also slidably connected. Through the threaded connection between the threaded sleeve and the air outlet pipe, the height of the threaded sleeve can be adjusted, and in conjunction with the sliding action between the threaded sleeve and the connecting ring, the normal rotation of the threaded sleeve can be ensured.

[0006] Preferably, the connecting ring is rotatably connected to one end of the connecting rod, and the other end of the connecting rod is rotatably connected to the crossbar. Four crossbars and four connecting rods are distributed at equal angles about the center of the air outlet pipe. Simultaneously, the crossbar is slidably connected to a fixing block fixed to the upper surface of the outer sleeve. The fixing blocks and crossbars are distributed in a one-to-one correspondence. A roller is also connected to the end of the crossbar furthest from the air outlet pipe via a bearing. The rotating threaded sleeve drives the connecting ring to move. Combined with the transmission action of the connecting rod, this provides a basic force for the movement of the crossbar and roller, thereby achieving roller position adjustment. The sliding action between the crossbar and the fixing block ensures the stability of the roller's movement.

[0007] Preferably, the first piston is also symmetrically fixed with sealing rings on the outside, and the sealing rings are in contact with the inner wall of the central tube to achieve sealing. In addition, a first spring is fixed between the first piston and the central tube, and a round hole is opened at the center of the first piston. Through the elastic action of the first spring, a basic guarantee can be provided for the position adjustment of the first piston.

[0008] Preferably, the throttling ring is slidably connected to the outer sleeve and the central tube, and the throttling ring cooperates with the air outlet to achieve a blocking effect. Through the action of the throttling ring, the opening size of the air outlet can be adjusted, thereby achieving automatic control of fluid flow.

[0009] Preferably, a fixing rod is also fixed inside the throttling ring, and one end of the fixing rod is fixed to the vertical rod, while the other end of the vertical rod is fixed to the first piston. Four vertical rods are provided. Through the above structure, the throttling ring and the first piston form an integral structure, thereby ensuring that the throttling ring moves with the first piston, thus ensuring the operation of the device.

[0010] Preferably, the control mechanism includes a sealing cylinder fixed coaxially with the first piston, and the inner diameter of the sealing cylinder is the same as the circular hole at the center of the first piston. A guide rod is fixed between the sealing cylinder and the first piston, and a second piston is slidably connected to the guide rod. The second piston is slidably connected to the sealing cylinder. Through the above structure, a basic guarantee can be provided for locking and unlocking the first piston, thereby ensuring the normal operation of the device.

[0011] Preferably, the second piston has several air holes at equal angles, and a second spring is fixed between the second piston and the sealing cylinder, and a second spring is also fixed between the second piston and the first piston. Through the elastic action of the second spring, a basic force can be provided for the automatic reset of the second piston.

[0012] Preferably, the upper end of the first piston is symmetrically fixed with a movable frame, and the movable frame is provided with a sliding groove. Both ends of the sliding groove are inclined structures. At the same time, the sliding groove and the convex shaft are slidably connected. The convex shaft is symmetrically fixed on the limiting rod, and the limiting rod and the sealing cylinder are slidably connected. The movable frame is moved by the second piston. With the sliding action between the sliding groove and the convex shaft, the basic force can be provided for the movement of the limiting rod, thereby ensuring the normal operation of the device.

[0013] Preferably, the limiting rod and the slot are engaged, and several slots are equally spaced on the support rod. The support rod is symmetrically fixed in the central tube. Through the engaging action between the limiting rod and the slot, the position of the first piston can be locked, thereby avoiding the throttle ring from frequently moving when the air pressure fluctuates at a low level, which would cause slight friction and accelerate the wear of the throttle ring, thus ensuring the service life of the throttle ring.

[0014] Compared with the prior art, the beneficial effects of the present invention are: 1. This wear-resistant downhole throttle adopts an adjustable auxiliary positioning mechanism, which can support and position the outer casing against the inner wall of the well pipe during the installation of the outer casing, thereby effectively avoiding shaking and collision during the installation process and ensuring the stability of the outer casing installation. With the elastic self-adjusting mechanism, the opening size of the air outlet can be adjusted by air pressure, thereby achieving automatic flow control and ensuring the stability of the flow in the pipeline. 2. This wear-resistant downhole throttle employs a control mechanism that allows the first piston to automatically lock when the gas pressure in the pipeline changes slightly, thereby automatically locking the position of the throttle ring. This prevents the throttle ring from frequently and slightly acting when the gas pressure fluctuation is small, thus extending the service life of the throttle ring. When the gas pressure in the pipeline changes significantly, the first piston can automatically unlock, thereby adjusting the position of the throttle ring and ensuring the stability of the flow rate in the pipeline. Attached Figure Description

[0015] Figure 1 This is a frontal cross-sectional three-dimensional structural diagram of the overall composition of the device of the present invention; Figure 2 This is a frontal three-dimensional structural diagram of the overall composition of the device of the present invention; Figure 3 This is a bottom-view cross-sectional three-dimensional structural diagram of the overall composition of the device of the present invention; Figure 4 This is a partial cross-sectional three-dimensional structural diagram of the auxiliary positioning mechanism of the present invention; Figure 5 This is a three-dimensional structural diagram of the first piston and the control mechanism of the present invention; Figure 6 This is a frontal three-dimensional structural diagram of the second piston of the present invention.

[0016] In the diagram: 1. Outer sleeve; 2. Central tube; 3. Air outlet; 4. Air outlet pipe; 5. Auxiliary positioning mechanism; 501. Threaded sleeve; 502. Connecting ring; 503. Connecting rod; 504. Crossbar; 505. Fixing block; 506. Roller; 6. First piston; 601. Sealing ring; 602. First spring; 7. Throttling ring; 701. Fixing rod; 702. Vertical rod; 8. Adjustment mechanism; 801. Sealing cylinder; 802. Guide rod; 803. Second piston; 804. Air hole; 805. Second spring; 806. Movable frame; 807. Slide groove; 808. Protruding shaft; 809. Limiting rod; 810. Slot; 811. Support rod. Detailed Implementation

[0017] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0018] Please see Figures 1-6 The present invention provides a technical solution: a wear-resistant downhole throttle, including an outer sleeve 1, a central tube 2 fixed coaxially inside the outer sleeve 1, a plurality of air outlets 3 opened at equal angles on the lower side of the central tube 2, a first piston 6 slidably connected coaxially inside the central tube 2, and a throttle ring 7 arranged directly below the first piston 6 to adjust the opening size of the air outlets 3. The auxiliary positioning mechanism 5 is used to guide and position the outer jacket 1 during installation, preventing the outer jacket 1 from shaking. The auxiliary positioning mechanism 5 is installed on the upper side of the outer jacket 1. The control mechanism 8 uses air pressure changes to achieve the self-locking and unlocking function of the first piston 6, and reduces the micro-floating friction of the throttling ring 7. The control mechanism 8 is connected to the first piston 6, and the control mechanism 8 is located inside the central tube 2.

[0019] The auxiliary positioning mechanism 5 includes a threaded sleeve 501 that is threadedly connected to the air outlet pipe 4, and the threaded sleeve 501 is slidably connected to the connecting ring 502, and the connecting ring 502 is slidably connected to the air outlet pipe 4; the connecting ring 502 is rotatably connected to one end of the connecting rod 503, and the other end of the connecting rod 503 is rotatably connected to the crossbar 504, and there are four crossbars 504 and four connecting rods 503 distributed at equal angles about the center of the air outlet pipe 4. At the same time, the crossbar 504 is slidably connected to the fixing block 505 fixed on the upper surface of the outer sleeve 1, and the fixing block 505 and the crossbar 504 are distributed in a one-to-one correspondence, and the end of the crossbar 504 away from the air outlet pipe 4 is also connected to a roller 506 by a bearing; When using this wear-resistant downhole choke, such as Figures 1-6 As shown, during the installation of the device with the natural gas well pipe, the position of the roller 506 is adjusted according to the diameter of the natural gas well pipe. By rotating the threaded sleeve 501, the height of the connecting ring 502 can be adjusted in conjunction with the threaded connection between the threaded sleeve 501 and the gas outlet pipe 4 and the sliding action between the threaded sleeve 501 and the connecting ring 502. When the connecting ring 502 moves, the crossbar 504 and the roller 506 can be moved under force in conjunction with the transmission action of the connecting rod 503. The sliding guide action between the crossbar 504 and the fixed block 505 can ensure the stability of the movement of the roller 506 until all four rollers 506 are in contact with the inner wall of the natural gas well pipe. Through the auxiliary support of the rollers 506, it can be ensured that the outer sleeve 1 is coaxial with the inner wall of the natural gas well pipe, and it can also prevent the outer sleeve 1 from being damaged by shaking when it is lowered into the natural gas well pipe. The first piston 6 is also symmetrically fixed with sealing rings 601 on its outer side, and the sealing rings 601 contact the inner wall of the central tube 2 to achieve a seal. The first piston 6 is also fixed with a first spring 602 between the first piston 6 and the central tube 2. At the same time, a round hole is opened at the center of the first piston 6. The throttle ring 7 is slidably connected with the outer sleeve 1 and the central tube 2. The throttle ring 7 cooperates with the air outlet 3 to achieve a blocking effect. The inner side of the throttle ring 7 is also fixed with a fixing rod 701. The fixing rod 701 is fixed to one end of the vertical rod 702, and the other end of the vertical rod 702 is fixed to the first piston 6. There are four vertical rods 702. After the device is installed, in actual use, such as Figures 1-6As shown, natural gas enters the central pipe 2 through the lower opening of the outer casing 1 and the throttling ring 7, and then enters the air between the outer casing 1 and the central pipe 2 through the outlet 3. Finally, it is discharged through the outlet pipe 4. In actual use, when the gas pressure is less than or equal to the elastic force of the first spring 602, the throttling ring 7 and the outlet 3 are separated, and the gas flow area of ​​the outlet 3 is at its maximum. When the downhole gas flow rate increases, the gas pressure under the first piston 6 increases. At this time, the gas pressure pushes the first piston 6 upward, causing the first spring 602 to contract under force. When the first spring 602 moves upward... Simultaneously, the vertical rod 702, the fixed rod 701, and the throttling ring 7 move upward, causing the throttling ring 7 to block the opening area of ​​the gas outlet 3, thereby reducing the gas flow area of ​​the gas outlet 3, thus achieving the effect of throttling and reducing pressure, and reducing the formation of hydrates, until the elastic force of the first spring 602 and the gas pressure force are in balance. According to the above principle, when the downhole gas flow decreases and the pressure decreases, the first piston 6 and the throttling ring 7 move downward under the action of the first spring 602, causing the throttling ring 7 to reduce the blocking of the opening area of ​​the gas outlet 3, thereby achieving the automatic adjustment function. The control mechanism 8 includes a sealing cylinder 801 fixed coaxially with the first piston 6, and the inner diameter of the sealing cylinder 801 is the same as the circular hole at the center of the first piston 6. A guide rod 802 is fixed between the sealing cylinder 801 and the first piston 6, and a second piston 803 is slidably connected to the guide rod 802. The second piston 803 is slidably connected to the sealing cylinder 801. Several air holes 804 are opened at equal angles on the second piston 803, and a second spring 805 is fixed between the second piston 803 and the sealing cylinder 801. The second piston 803 is also fixed to the first piston 6. There is a second spring 805; the upper end of the first piston 6 is symmetrically fixed with a movable frame 806, and the movable frame 806 is provided with a sliding groove 807, and the upper and lower ends of the sliding groove 807 are both inclined structures. At the same time, the sliding groove 807 is slidably connected to the convex shaft 808. The convex shaft 808 is symmetrically fixed to the limiting rod 809, and the limiting rod 809 is slidably connected to the sealing cylinder 801; the limiting rod 809 is engaged with the slot 810, and several slots 810 are equally spaced on the support rod 811, and the support rod 811 is symmetrically fixed inside the central tube 2. During the use of the device, such as Figures 1-6As shown, because the second piston 803 has an air hole 804, the air pressure above and below the second piston 803 in the sealing cylinder 801 is balanced. During the process of pressure fluctuation at the bottom of the well, when the pressure fluctuation is small, the pressure on the lower side of the second piston 803 and the first piston 6 increases. Due to the small pressure fluctuation, some gas enters the cavity above the second piston 803 through the air hole 804. Because the diameter of the air hole 804 is small, some gas exerts a force on the second piston 803, causing the second piston 803 to move upward a certain distance. At this time, the second spring 805 above the second piston 803 is compressed. The second spring 805 below 803 is stretched by force. When the second piston 803 moves, it drives the movable frame 806 and the slide 807 to move synchronously. Due to the small pressure fluctuation, the movement distance of the second piston 803, the movable frame 806 and the slide 807 is effective. That is, the sliding between the slide 807 and the convex shaft 808 is located in the vertical groove, so that the limit rod 809 and the slot 810 maintain the locking action, ensuring that the first piston 6 is in the locked state. This ensures that when the pressure fluctuation at the bottom of the well is small, neither the first piston 6 nor the throttling ring 7 will be moved by force. This can avoid the throttling ring 7 from frequent friction when the pressure fluctuation is small, thereby ensuring the service life of the throttling ring 7. When the bottom hole pressure fluctuates significantly, it is described as an increase in gas pressure. According to the above principle, the gas exerts a greater force on the second piston 803, causing the second piston 803 to move a greater distance. This, in turn, moves the movable frame 806 and the slide groove 807. When the lower inclined groove of the slide groove 807 contacts and slides against the convex shaft 808, the limiting rod 809 is forced to move inward toward the sealing cylinder 801. When the limiting rod 809 separates from the slot 810, the limiting and locking effect of the first piston 6 is released, allowing the first piston 6 to move upward synchronously under the action of gas pressure, and driving the throttling ring 7 to achieve gas flow at the outlet 3. The adjustment of the flow area continues until the elastic force of the first spring 602 and the gas pressure force are balanced. At this time, due to the action of the air hole 804, the high-pressure gas below the second piston 803 continuously enters the space above the second piston 803 through the air hole 804. When the gas pressure above and below the second piston 803 gradually decreases, the second piston 803 can be automatically reset by the elastic force of the second spring 805. This will drive the movable frame 806 and the slide 807 to reset, and then the limit rod 809 will reset and engage with the slots 810 at different positions on the support rod 811, thereby achieving the high-pressure locking effect at the bottom of the well. When the bottom pressure decreases, the gas in the space above the second piston 803 is under high pressure in the early stage, so the gas pressure force above the second piston 803 is greater than the gas pressure force below the second piston 803. At this time, the second piston 803 moves downward under the pressure of the space above, and some of the high-pressure gas above the second piston 803 is simultaneously output downward through the gas hole 804. According to the above principle, the second piston 803, the movable frame 806 and the slide groove 807 move downward under the force. When the inclined groove above the slide groove 807 slides with the convex shaft 808, the limiting rod 809 can be moved inward to the sealing cylinder 801. When the limiting rod 809 separates from the slot 810, the limiting and locking function of the first piston 6 can be released. At this time, under the elastic action of the first spring 602, the first piston 6 and the throttle ring 7 move downward, which increases the gas flow area of ​​the gas outlet 3, thereby realizing the self-adjustment function. In summary, based on the above principles, this downhole choke can effectively reduce mechanical wear caused by frequent adjustments of the choke ring 7 due to small gas pressure changes during actual use, extend the maintenance cycle by more than 50%, and significantly reduce the frequency and cost of well workover operations.

[0020] It should be noted that, in this document, the terms “comprising,” “including,” or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such process, method, article, or apparatus.

[0021] This article uses specific examples to illustrate the principles and implementation methods of the present invention. The above examples are only for the purpose of helping to understand the method and core ideas of the present invention. The above descriptions are only preferred embodiments of the present invention. It should be noted that due to the limitations of textual expression, while there are objectively infinite specific structures, those skilled in the art can make several improvements, modifications, or changes without departing from the principles of the present invention, and can also combine the above technical features in an appropriate manner. These improvements, modifications, changes, or combinations, or the direct application of the inventive concept and technical solution to other situations without modification, should all be considered within the scope of protection of the present invention.

Claims

1. A wear-resistant downhole choke, comprising an outer casing (1), wherein a central tube (2) is coaxially fixed inside the outer casing (1), characterized in that: The central tube (2) has several air outlets (3) at equal angles on its lower side. A first piston (6) is slidably connected inside the central tube (2). A throttling ring (7) is provided directly below the first piston (6) to adjust the size of the air outlets (3). An auxiliary positioning mechanism (5) is used to guide and position the outer jacket (1) during installation to prevent the outer jacket (1) from shaking during installation. The auxiliary positioning mechanism (5) is installed on the upper side of the outer jacket (1). The control mechanism (8) uses air pressure changes to achieve the self-locking and unlocking function of the first piston (6) and reduce the micro-floating friction of the throttling ring (7). The control mechanism (8) is connected to the first piston (6) and is located inside the central tube (2).

2. The wear-resistant downhole choke according to claim 1, characterized in that: The auxiliary positioning mechanism (5) includes a threaded sleeve (501) that is threaded to the air outlet pipe (4), and the threaded sleeve (501) and the connecting ring (502) are slidably connected, and the connecting ring (502) and the air outlet pipe (4) are slidably connected.

3. The wear-resistant downhole choke according to claim 2, characterized in that: The connecting ring (502) is rotatably connected to one end of the connecting rod (503), and the other end of the connecting rod (503) is rotatably connected to the crossbar (504). The crossbar (504) and the connecting rod (503) are distributed at equal angles about the center of the air outlet pipe (4). The crossbar (504) is slidably connected to the fixing block (505) fixed on the upper surface of the outer sleeve (1). The fixing block (505) and the crossbar (504) are distributed in a one-to-one correspondence. The end of the crossbar (504) away from the air outlet pipe (4) is also connected to a roller (506) by a bearing.

4. The wear-resistant downhole choke according to claim 1, characterized in that: The first piston (6) is also symmetrically fixed with sealing rings (601) on the outside, and the sealing rings (601) are in contact with the inner wall of the central tube (2) to achieve sealing. The first piston (6) and the central tube (2) are also fixed with a first spring (602), and a round hole is opened at the center of the first piston (6).

5. A wear-resistant downhole choke according to claim 1, characterized in that: The throttling ring (7) is slidably connected to the outer sleeve (1) and the central tube (2), and the throttling ring (7) cooperates with the air outlet (3) to achieve a shielding effect.

6. The wear-resistant downhole choke according to claim 1, characterized in that: The inner side of the throttling ring (7) is also fixed with a fixing rod (701), and one end of the fixing rod (701) is fixed to the vertical rod (702), and the other end of the vertical rod (702) is fixed to the first piston (6). At the same time, four vertical rods (702) are provided.

7. A wear-resistant downhole choke according to claim 1, characterized in that: The control mechanism (8) includes a sealing cylinder (801) fixed coaxially with the first piston (6), and the inner diameter of the sealing cylinder (801) is the same as the circular hole at the center of the first piston (6). A guide rod (802) is fixed between the sealing cylinder (801) and the first piston (6), and a second piston (803) is slidably connected on the guide rod (802). The second piston (803) is slidably connected to the sealing cylinder (801).

8. A wear-resistant downhole choke according to claim 7, characterized in that: The second piston (803) has several air holes (804) at equal angles, and a second spring (805) is fixed between the second piston (803) and the sealing cylinder (801), and a second spring (805) is also fixed between the second piston (803) and the first piston (6).

9. A wear-resistant downhole throttle according to claim 8, characterized in that: The first piston (6) has a movable frame (806) fixed symmetrically on the left and right sides at the upper end, and a sliding groove (807) is provided on the movable frame (806). The upper and lower ends of the sliding groove (807) are both inclined structures. At the same time, the sliding groove (807) and the convex shaft (808) are slidably connected. The convex shaft (808) is symmetrically fixed on the limiting rod (809) at the front and back, and the limiting rod (809) and the sealing cylinder (801) are slidably connected.

10. A wear-resistant downhole throttle according to claim 9, characterized in that: The limiting rod (809) and the slot (810) are connected by a snap-fit ​​connection, and several slots (810) are equally spaced on the support rod (811), and the support rod (811) is symmetrically fixed in the center tube (2).

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