Wear-resistant downhole choke

Abstract

The application discloses a wear-resistant downhole throttling device and relates to the technical field of downhole throttling devices.The wear-resistant downhole throttling device comprises a sleeve, a center pipe fixed coaxially in the sleeve, a plurality of gas outlets arranged at equal angles on the lower side of the center pipe, a first piston connected coaxially and slidably in the center pipe, and a throttling ring arranged right below the first piston to realize the adjustment of the opening size of the gas outlets.The wear-resistant downhole throttling device adopts a control mechanism, so that when the gas pressure in the pipeline changes slightly during the use of the device, the first piston can be automatically locked, the position of the throttling ring can be automatically locked, the throttling ring can be prevented from frequently producing slight effects when the gas pressure fluctuation range is small, and the service life of the throttling ring can be prolonged;when the gas pressure in the pipeline changes greatly, the first piston can be automatically unlocked, the position of the throttling ring can be adjusted, and the stability of the flow in the pipeline can be ensured.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of downhole throttling device, in particular to a wear-resistant downhole throttling device. BACKGROUND

[0002] The downhole throttling device is a key tool for controlling the fluid flow in the wellbore in oil and gas field development, which mainly controls the fluid flow, stabilizes the wellhead pressure and prevents the generation of hydrate, and is widely used in natural gas wells;

[0003] The existing downhole throttling device, such as the downhole throttling device disclosed in CN106285580B, comprises a shell with a gas outlet, the shell is provided with a gas inlet and a gas channel communicating the gas inlet and the gas outlet, the shell is provided with a floating throttling member capable of floating according to the gas inlet pressure and having a throttling member cavity, the gas channel comprises a first channel provided on the shell along the floating direction of the floating throttling member and a second channel provided on the floating throttling member and communicating with the throttling member cavity, the first channel and the second channel are oppositely arranged and communicated, the communication area of the first channel and the second channel is maximum when the floating throttling member is not floating, the floating throttling member can float to reduce the communication area between the first channel and the second channel when the gas pressure increases, thereby achieving the throttling and pressure reduction effect and reducing the generation of hydrate, and the floating throttling member increases the communication area of the first channel and the second channel when the gas pressure decreases, thereby ensuring the flow rate;

[0004] The above-mentioned existing downhole throttling device can automatically adjust the flow rate in the pipeline by changing the fluid pressure during actual use, but the underground natural gas pressure changes in real time during actual use, so that the throttling member moves whether the gas pressure fluctuates greatly or slightly, the gas pressure fluctuation adaptability of the throttling member is poor, and when the throttling member moves frequently due to small amplitude fluctuation of the gas pressure, the wear of the throttling member is accelerated, thereby affecting the service life of the device. SUMMARY

[0005] The present application aims to provide a wear-resistant downhole throttling device to solve the problems in the background art.

[0006] To achieve the above-mentioned purpose, the present application provides the following technical scheme: a wear-resistant downhole throttling device, comprising a sleeve, a center pipe coaxially fixed in the sleeve, a plurality of gas outlets are arranged at equal angles on the lower side of the center pipe, a first piston coaxially connected in the center pipe is slidably connected, a throttling ring is arranged below the first piston to adjust the opening size of the gas outlet;

[0007] An auxiliary positioning mechanism is used to guide and position the installation of the sleeve to prevent the sleeve from shaking during installation, and the auxiliary positioning mechanism is installed on the upper side of the sleeve;

[0008] The regulating mechanism is connected with the first piston and is arranged in the central pipe.

[0009] Preferably, the auxiliary positioning mechanism comprises a threaded sleeve threadedly connected with the air outlet pipe, the threaded sleeve is slidingly connected with the connecting ring, and the connecting ring is slidingly connected with the air outlet pipe.

[0010] Preferably, one end of the connecting rod is rotatably connected with the connecting ring, the other end of the connecting rod is rotatably connected with the horizontal rod, the horizontal rod and the connecting rod are equally angularly distributed about the center of the air outlet pipe, the horizontal rod is slidingly connected with the fixing block fixed on the upper end face of the outer sleeve, the fixing block and the horizontal rod are one-to-one correspondingly distributed, the end of the horizontal rod away from the air outlet pipe is rotatably connected with the roller, the threaded sleeve is rotated to drive the connecting ring to move, the horizontal rod is driven to move to provide basic force for the movement of the roller, thereby adjusting the position of the roller, and the sliding movement between the horizontal rod and the fixing block ensures the stability of the movement of the roller.

[0011] Preferably, the first piston is symmetrically fixed with a sealing ring on the outside, the sealing ring is in contact with the inner wall of the central pipe to achieve sealing, a first spring is further fixed between the first piston and the central pipe, and a circular hole is further arranged in the central position of the first piston.

[0012] Preferably, the throttle ring is slidingly connected with the outer sleeve and the central pipe, and the throttle ring cooperates with the air outlet to achieve the shielding effect, so that the opening size of the air outlet can be adjusted to automatically control the flow of fluid.

[0013] Preferably, the throttle ring is further fixed with a fixing rod on the inside, one end of the fixing rod is fixed with the vertical rod, the other end of the vertical rod is fixed with the first piston, and the vertical rod has four rods.

[0014] Preferably, the control mechanism comprises a sealing cylinder coaxially fixed with the first piston, the inner diameter of the sealing cylinder is same as the center position hole of the first piston, a guide rod is fixed between the sealing cylinder and the first piston, a second piston is slidably connected on the guide rod, and the second piston is slidably connected with the sealing cylinder.

[0015] Preferably, a plurality of gas holes are equiangularly arranged on the second piston, 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, so that the elastic effect of the second spring can provide a basic force for the automatic reset of the second piston.

[0016] Preferably, a movable frame is symmetrically fixed on the upper end of the first piston, a sliding groove is arranged on the movable frame, the upper and lower ends of the sliding groove are inclined, the sliding groove is slidably connected with a convex shaft, the convex shaft is symmetrically fixed on a limiting rod, the limiting rod is slidably connected with the sealing cylinder, the movable frame is moved by the second piston, and the sliding effect between the sliding groove and the convex shaft can provide a basic force for the movement of the limiting rod, thereby ensuring the normal operation of the device.

[0017] Preferably, the limiting rod is clamped with the clamping groove, a plurality of clamping grooves are equidistantly arranged on the supporting rod, and the supporting rod is symmetrically fixed in the center pipe, so that the clamping effect between the limiting rod and the clamping groove can realize the position locking of the first piston, thereby avoiding the slight friction of the throttling ring caused by frequent action when the air pressure is low, accelerating the wear of the throttling ring, and ensuring the service life of the throttling ring.

[0018] Compared with the prior art, the present application has the following advantages:

[0019] 1. The wear-resistant downhole throttling device adopts an adjustable auxiliary positioning mechanism, which can realize the support and positioning of the outer sleeve and the inner wall of the well pipe during installation, thereby effectively avoiding the shaking and knocking during the installation of the outer sleeve, ensuring the stability of the installation of the outer sleeve, and cooperating with the elastic self-adjusting mechanism to realize the size adjustment of the outlet opening by using air pressure, thereby realizing the automatic flow control and ensuring the stability of the flow in the pipeline.

[0020] 2. The wear-resistant downhole throttling device adopts a control mechanism, which can realize the automatic locking of the first piston when the air pressure in the pipeline changes slightly during use, thereby realizing the automatic locking of the position of the throttling ring and avoiding the frequent slight action of the throttling ring when the air pressure fluctuation is small, thereby prolonging the service life of the throttling ring, and when the air pressure in the pipeline changes greatly, the automatic unlocking of the first piston can be realized, thereby realizing the adjustment of the position of the throttling ring and ensuring the stability of the flow in the pipeline.BRIEF DESCRIPTION OF DRAWINGS BRIEF DESCRIPTION OF DRAWINGS

[0021] Figure 1 It is the whole composition of the device of the present application front view cross section solid structure schematic diagram;

[0022] Figure 2 It is the whole composition of the device of the present application front view solid structure schematic diagram;

[0023] Figure 3 It is the whole composition of the device of the present application bottom view cross section solid structure schematic diagram;

[0024] Figure 4 It is the composition of the auxiliary positioning mechanism of the present application partial cross section solid structure schematic diagram;

[0025] Figure 5 It is the first piston and control mechanism of the present application solid structure schematic diagram;

[0026] Figure 6 It is the second piston of the present application front view solid structure schematic diagram.

[0027] In the figure: 1, the outer sleeve; 2, the center tube; 3, the gas outlet; 4, the gas outlet pipe; 5, the auxiliary positioning mechanism; 501, the threaded sleeve; 502, the connecting ring; 503, the connecting rod; 504, the crossbar; 505, the fixed block; 506, the roller; 6, the first piston; 601, the sealing ring; 602, the first spring; 7, the throttle ring; 701, the fixed rod; 702, the vertical rod; 8, the control mechanism; 801, the sealing cylinder; 802, the guide rod; 803, the second piston; 804, the air hole; 805, the second spring; 806, the movable frame; 807, the sliding groove; 808, the convex shaft; 809, the limiting rod; 810, the clamping groove; 811, the support rod. DETAILED DESCRIPTION

[0028] The technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor fall within the scope of protection of the present application.

[0029] Please refer to Figures 1-6 The present application provides a technical solution: a wear-resistant downhole throttling device, comprising an outer sleeve 1, a center tube 2 coaxially fixed in the outer sleeve 1, a plurality of gas outlets 3 evenly arranged on the lower side of the center tube 2, a first piston 6 coaxially connected in the center tube 2, and a throttle ring 7 arranged below the first piston 6 to adjust the opening size of the gas outlet 3.

[0030] Auxiliary positioning mechanism 5 is used for realizing the guiding positioning effect of the installation of the outer sleeve 1, preventing the outer sleeve 1 from shaking during the installation, and the auxiliary positioning mechanism 5 is installed on the upper side of the outer sleeve 1;

[0031] The regulating mechanism 8 is used for realizing the self-locking and unlocking effects of the first piston 6 by means of the change of the air pressure, reducing the micro-floating friction effect of the throttling ring 7, and the regulating mechanism 8 is connected with the first piston 6, and the regulating mechanism 8 is arranged in the central pipe 2.

[0032] The auxiliary positioning mechanism 5 comprises a threaded sleeve 501 which is threadedly connected with the air outlet pipe 4, and the threaded sleeve 501 is slidably connected with a connecting ring 502, and the connecting ring 502 is slidably connected with the air outlet pipe 4; one end of a connecting rod 503 is rotatably connected with the connecting ring 502, and the other end of the connecting rod 503 is rotatably connected with a cross rod 504, and the cross rod 504 and the connecting rod 503 are equally angularly distributed with four around the center of the air outlet pipe 4, and the cross rod 504 is slidably connected with a fixed block 505 which is fixed on the upper end face of the outer sleeve 1, the fixed block 505 is one-to-one correspondingly distributed with the cross rod 504, and the end of the cross rod 504 away from the air outlet pipe 4 is further bearingly connected with a roller 506;

[0033] When the wear-resistant downhole throttling device is used, as shown in the figure, Figures 1-6 when the device is installed with the natural gas well pipe, the position of the roller 506 is adjusted according to the diameter of the natural gas well pipe, the height of the connecting ring 502 is adjusted by rotating the threaded sleeve 501, cooperating with the threaded connection between the threaded sleeve 501 and the air outlet pipe 4 and the sliding action between the threaded sleeve 501 and the connecting ring 502, when the connecting ring 502 moves, the cross rod 504 and the roller 506 can be forced to move by cooperating with the transmission action of the connecting rod 503, and the stability of the movement of the roller 506 can be ensured by cooperating with the sliding guiding action between the cross rod 504 and the fixed block 505, until the four rollers 506 are in contact with the inner wall of the natural gas well pipe, the coaxiality of the outer sleeve 1 and the inner wall of the natural gas well pipe can be ensured by the auxiliary supporting action of the roller 506, and the outer sleeve 1 can be prevented from being damaged by knocking when it is lowered into the natural gas well pipe due to shaking;

[0034] The first piston 6 is further fixed with a sealing ring 601 which is symmetrically arranged on the outer side of the first piston 6 and is in contact with the inner wall of the central pipe 2 to realize sealing, and the first piston 6 is further fixed with a first spring 602 between the first piston 6 and the central pipe 2, and a circular hole is arranged at the center position of the first piston 6; the throttling ring 7 is slidably connected with the outer sleeve 1 and the central pipe 2, and the throttling ring 7 cooperates with the air outlet 3 to realize the shielding effect; the throttling ring 7 is further fixed with a fixed rod 701 on the inner side of the throttling ring 7, and the fixed rod 701 is fixed with a vertical rod 702 at one end, and the other end of the vertical rod 702 is fixed with the first piston 6, and the vertical rod 702 is provided with four;

[0035] After the device is installed, in actual use, as shown in Figures 1-6 the natural gas enters the center pipe 2 through the lower opening of the outer sleeve 1 and the throttling ring 7, enters the air between the outer sleeve 1 and the center pipe 2 through the gas outlet 3, and is finally discharged through the gas outlet pipe 4. In actual use, when the gas pressure force is less than or equal to the elastic force of the first spring 602, at this time, the throttling ring 7 is separated from the gas outlet 3, and the gas flow area of the gas outlet 3 is maximum. When the downhole gas flow increases, the gas pressure on the lower side of the first piston 6 increases, and the first piston 6 is pushed upward under the action of the gas pressure, so that the first spring 602 is contracted under stress. When the first spring 602 moves upward, the vertical rod 702, the fixed rod 701 and the throttling ring 7 are driven to move upward synchronously, so that the throttling ring 7 shields the opening area of the gas outlet 3, thereby reducing the gas flow area of the gas outlet 3, and the throttling and pressure reduction effect is realized, and the generation of hydrate is reduced. Until the elastic force of the first spring 602 and the gas pressure force are balanced. According to the above principle, when the downhole gas flow decreases to reduce the pressure, at this time, the first piston 6 and the throttling ring 7 move downward under the action of the first spring 602, so that the throttling ring 7 reduces the shielding of the opening area of the gas outlet 3, thereby realizing the automatic adjustment effect.

[0036] The control mechanism 8 comprises a sealing cylinder 801 coaxially fixed with the first piston 6, and the inner diameter of the sealing cylinder 801 is the same as the center position circular hole of the first piston 6. A guide rod 802 is fixed between the sealing cylinder 801 and the first piston 6, a second piston 803 is slidably connected to the guide rod 802, and the second piston 803 is slidably connected with the sealing cylinder 801. A plurality of gas holes 804 are equally angularly arranged on the second piston 803, a second spring 805 is fixed between the second piston 803 and the sealing cylinder 801, and the second spring 805 is also fixed between the second piston 803 and the first piston 6. An activity frame 806 is symmetrically fixed on the upper end of the first piston 6, a sliding groove 807 is arranged on the activity frame 806, the sliding groove 807 has a slope structure at both ends, the sliding groove 807 is slidably connected with a convex shaft 808, the convex shaft 808 is symmetrically fixed on a limiting rod 809, and the limiting rod 809 is slidably connected with the sealing cylinder 801. The limiting rod 809 is clamped with a clamping groove 810, a plurality of clamping grooves 810 are equally spaced on a support rod 811, and the support rod 811 is symmetrically fixed in the center pipe 2.

[0037] In the use of the device, as shown in Figures 1-6As shown, due to the gas hole 804 opened on the second piston 803, the gas pressure above the second piston 803 in the sealing cylinder 801 and the gas pressure below the second piston 803 are in balance. During the fluctuation of the bottom hole pressure, when the fluctuation of the bottom hole pressure is small, the pressure on the lower side of the second piston 803 and the first piston 6 increases. Since the pressure fluctuation is small, part of the gas enters the cavity above the second piston 803 through the gas hole 804 on the second piston 803. Since the diameter of the gas hole 804 is small, part of the gas acts on the second piston 803, so that the second piston 803 moves upward by a certain distance. At this time, the second spring 805 above the second piston 803 is contracted under stress, and the second spring 805 below the second piston 803 is stretched under stress. When the second piston 803 moves, the movable frame 806 and the sliding groove 807 are driven to move synchronously. Since the gas pressure fluctuation is small, the moving distance of the second piston 803, the movable frame 806 and the sliding groove 807 is effective, that is, the sliding between the sliding groove 807 and the convex shaft 808 is located in the vertical slot, so that the limiting rod 809 and the clamping groove 810 remain clamped, ensuring that the first piston 6 is in a locked state, thereby ensuring that the first piston 6 and the throttle ring 7 do not move under stress when the bottom hole pressure fluctuation is small, and thereby avoiding frequent friction of the throttle ring 7 under small pressure fluctuation, thereby ensuring the service life of the throttle ring 7.

[0038] When the bottom hole pressure fluctuation is large, the gas pressure increases. According to the above principle, the gas acts on the second piston 803 to generate a larger force, so that the moving distance of the second piston 803 increases, thereby driving the movable frame 806 and the sliding groove 807 to move. When the inclined groove on the lower side of the sliding groove 807 contacts and slides with the convex shaft 808, the limiting rod 809 moves to the inside of the sealing cylinder 801 under stress. When the limiting rod 809 is separated from the clamping groove 810, the limiting and locking effect of the first piston 6 can be released, so that the first piston 6 moves upward synchronously under the action of the gas pressure, and drives the throttle ring 7 to move upward, thereby realizing the adjustment effect of the gas flow area of the gas outlet 3. Until the elastic force of the first spring 602 and the gas pressure force are balanced, and at this time, due to the effect of the gas hole 804, the high-pressure gas below the second piston 803 continuously enters the space above the second piston 803 through the gas hole 804. When the gas pressure above and below the second piston 803 gradually decreases, the second piston 803 can be automatically reset under the elastic force of the second spring 805, thereby driving the movable frame 806 and the sliding groove 807 to reset, and thereby making the limiting rod 809 reset and clamped with the clamping groove 810 at different positions on the supporting rod 811, thereby realizing the high-pressure locking effect of the bottom hole.

[0039] When the well bottom pressure decreases, the gas above the second piston 803 is in a high pressure state at the previous stage, so that 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 is forced to move downward under the high pressure of the space above, and the high pressure gas above the second piston 803 is simultaneously output downward through the gas hole 804, according to the above principle, at this time, the second piston 803, the movable frame 806 and the sliding groove 807 are forced to move downward, when the inclined groove above the sliding groove 807 slides with the convex shaft 808, the limiting rod 809 can be forced to move to the inside of the sealing cylinder 801, when the limiting rod 809 is separated from the clamping groove 810, the limiting locking effect 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 are forced to move downward, so that the gas flow area of the gas outlet 3 is increased, thereby realizing self-regulation;

[0040] In summary, according to the above principle, the downhole throttling device can effectively reduce the mechanical wear caused by frequent adjustment of the throttle ring 7 due to small amplitude pressure change, the maintenance cycle is prolonged by more than 50%, and the workover operation frequency and cost are significantly reduced.

[0041] It should be noted that in this document, the terms "comprising", "including", or any other variant thereof are intended to cover non-exclusive inclusions, so that a process, method, article or device including a series of elements not only includes those elements, but also includes other elements not explicitly listed, or inherent to such a process, method, article or device.

[0042] The principles and embodiments of the present application are described by specific examples in this document, and the above examples are only used to help understand the method of the present application and its core idea. The above description is only the preferred embodiment of the present application, it should be pointed out that due to the limitation of language expression, there are infinite specific structures, for ordinary skilled in the art, without departing from the principles of the present application, a number of improvements, refinements or changes can be made, or the above technical features can be combined in a proper way, these improvements, refinements, changes or combinations, or without improvement, the concept and technical scheme of the present application are directly applied to other occasions, all should be regarded as the protection scope of the present application.

Claims

1. A wear resistant downhole choke comprising an outer sleeve (1) and a central pipe (2) fixed coaxially inside the sleeve (1), characterized in that: The center pipe (2) lower side equiangularly opens several air outlets (3), the coaxial first piston (6) is slidably connected in the center pipe (2), the throttle ring (7) is arranged below the first piston (6) for adjusting the opening size of the air outlet (3); The auxiliary positioning mechanism (5) is installed on the upper side of the outer sleeve (1) for guiding and positioning the installation of the outer sleeve (1) to prevent the outer sleeve (1) from shaking during installation. The control mechanism (8) is connected with the first piston (6) and is arranged in the center pipe (2) for realizing the self-locking and unlocking of the first piston (6) by using the change of air pressure, reducing the micro-floating friction of the throttle ring (7), the control mechanism (8) comprises a sealing cylinder (801) fixed coaxially with the first piston (6), the inner diameter of the sealing cylinder (801) is the same as the center hole of the first piston (6), a guide rod (802) is fixed between the sealing cylinder (801) and the first piston (6), a second piston (803) is slidably connected on the guide rod (802), the second piston (803) is slidably connected with the sealing cylinder (801), a plurality of air holes (804) are equiangularly arranged on the second piston (803), 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), a movable frame (806) is symmetrically fixed on the upper end of the first piston (6), a sliding groove (807) is arranged on the movable frame (806), the upper and lower ends of the sliding groove (807) are inclined, the sliding groove (807) is slidably connected with a convex shaft (808), the convex shaft (808) is symmetrically fixed on a limiting rod (809), and the limiting rod (809) is slidably connected with the sealing cylinder (801).

2. A wear resistant downhole choke as defined in claim 1, wherein: The auxiliary positioning mechanism (5) comprises a threaded sleeve (501) threadedly connected with the air outlet pipe (4), the threaded sleeve (501) is slidably connected with a connecting ring (502), and the connecting ring (502) is slidably connected with the air outlet pipe (4).

3. A wear resistant downhole choke as defined in claim 2, wherein: The connecting ring (502) is rotatably connected with one end of a connecting rod (503), the other end of the connecting rod (503) is rotatably connected with a cross rod (504), the cross rod (504) and the connecting rod (503) are equiangularly distributed about the center of the air outlet pipe (4), the cross rod (504) is slidably connected with a fixed block (505) fixed on the upper end face of the outer sleeve (1), the fixed block (505) is one-to-one correspondingly distributed with the cross rod (504), and the end of the cross rod (504) away from the air outlet pipe (4) is further bearing-connected with a roller (506).

4. A wear resistant downhole choke as defined in claim 1, wherein: The first piston (6) is also fixed with a sealing ring (601) which is symmetrical up and down, and the sealing ring (601) is in contact with the inner wall of the center tube (2) to realize sealing, and the first piston (6) is also fixed with a first spring (602) between the center tube (2), and a round hole is also arranged in the center position of the first piston (6).

5. A wear resistant downhole choke as defined in claim 1, wherein: The throttle ring (7) is in sliding connection with the outer sleeve (1) and the center tube (2), and the throttle ring (7) cooperates with the gas outlet (3) to realize the shielding effect.

6. A wear resistant downhole choke in accordance with claim 1 wherein: The inner side of the throttle ring (7) is also fixed with a fixed rod (701), and the fixed rod (701) and one end of the vertical rod (702) are fixed with each other, and the other end of the vertical rod (702) is fixed with the first piston (6), and the vertical rod (702) is provided with four.

7. A wear resistant downhole choke as defined in claim 6, wherein: The limiting rod (809) and the clamping groove (810) are in clamping connection, a plurality of clamping grooves (810) are arranged at equal intervals on the supporting rod (811), and the supporting rod (811) is fixed in the center tube (2) in left-right symmetry.

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