A variable diameter wellhead device for a plunger gas lift well

Abstract

This invention relates to the field of plunger gas lift technology, and more particularly to a variable-diameter wellhead device for plunger gas lift wells, comprising: a variable-diameter core tube for insertion into a wellhead tree pipe, a first through hole on the side of the wellhead tree pipe, a drive section along the height direction on the side of the variable-diameter core tube, a drive assembly on the side of the wellhead tree pipe corresponding to the first through hole, the drive assembly being drivenly connected to the drive section, and the top of the outer side wall of the variable-diameter core tube and the wellhead tree pipe being connected by a first upper uncoupling gear sleeve; and a uncoupling device disposed on the side of the variable-diameter core tube for attaching and detaching the first upper uncoupling gear sleeve. This invention solves the technical problem of leakage caused by mismatch between the inner diameter of the tubing and the plunger in existing systems. By changing the inner diameter of the wellhead tree pipe through the variable-diameter core tube, the mismatch between the plunger and the tubing diameter is avoided, thus improving the production efficiency of the produced fluid.

Description

Technical Field

[0001] This invention relates to the field of plunger gas lift technology, and more particularly to a variable diameter wellhead device for plunger gas lift wells. Background Technology

[0002] In current unconventional gas well plunger lift processes, many wells suffer from a mismatch between the tubing inner diameter and the wellhead tree diameter; the tree diameter is large, while the tubing inner diameter is small. The plunger is selected to match the tubing inner diameter, leaving a gap between them. However, in existing wellhead trees with large diameters and small plunger diameters, the excessive gap causes significant fluid slippage within the tree, leading to gas rising below the plunger. This results in two consequences: first, severe fluid leakage within the tree, rendering the plunger lift operation ineffective; second, the plunger cannot be pushed to the wellhead plunger catcher, hindering plunger capture and replacement.

[0003] In addition, due to long-term field use, the threads between the buffer and the main pipe are difficult to unscrew, making it impossible to remove the buffer and open the wellhead, which affects the next step of the operation. Summary of the Invention

[0004] This invention aims to at least solve one of the technical problems existing in related technologies. To this end, this invention provides a variable diameter wellhead device for plunger gas lift wells, which solves the technical problem that leakage is easily caused by the mismatch between the inner diameter of the tubing and the plunger in existing systems. By changing the inner diameter of the wellhead tree pipe through the variable diameter core tube, the mismatch between the plunger and the pipe diameter is avoided, thereby improving the production efficiency of the produced fluid.

[0005] This invention provides a variable diameter wellhead device for a plunger gas lift well. The wellhead of the plunger gas lift well is equipped with a wellhead tree main pipe. The variable diameter wellhead device includes:

[0006] A variable diameter core tube is inserted into the wellhead tree main tube. A first through hole is provided on the side of the wellhead tree main tube. A drive section is provided on the side of the variable diameter core tube along the height direction. A drive assembly is provided on the side of the wellhead tree main tube corresponding to the first through hole. The drive assembly is drivenly connected to the drive section. The top of the outer side wall of the variable diameter core tube and the wellhead tree main tube are connected by a first upper shackle gear sleeve.

[0007] A shackle device is provided on the side of the variable diameter core tube, and the shackle device is used to install and remove the first upper shackle gear sleeve.

[0008] A further improvement of the present invention on the variable diameter wellhead device for a plunger gas lift well is that the drive section is a rack formed on the side of the variable diameter core tube;

[0009] The drive assembly includes a gear seat mounted on the outer wall of the main wellhead corresponding to the first through hole and a drive gear rotatably connected to the gear seat. The drive gear meshes with the rack, and the drive gear is connected to a drive gear shaft, which is connected to a first handle.

[0010] A further improvement of the variable diameter wellhead device for a plunger gas lift well of the present invention is that a reinforcing part is formed on the wellhead tree main pipe corresponding to the position of the first through hole.

[0011] A further improvement of the variable diameter wellhead device for a plunger gas lift well of the present invention is that a sealing ring is provided between the wellhead tree main tube and the variable diameter core tube.

[0012] A further improvement of the variable diameter wellhead device for a plunger gas lift well of the present invention is that the top end of the variable diameter core tube is connected to a buffer via a buffer connector, the buffer including a buffer cap and a buffer spring.

[0013] A further improvement of the variable diameter wellhead device for a plunger gas lift well of the present invention is that the buffer connector and the outer wall of the variable diameter core tube are connected by a second upper shackle gear sleeve, and the second upper shackle gear sleeve is driven to the shackle device.

[0014] A further improvement of the variable diameter wellhead device for a plunger gas lift well of the present invention is that the uncoupling device includes:

[0015] Mounting base;

[0016] A gearbox, the gearbox being fixed to the top of the mounting base;

[0017] A first shaft portion, height adjustable, is connected to the gearbox. The first shaft portion includes a lifting shaft, a central shaft, and a lower straightening shaft connected in sequence. The top of the lifting shaft and the bottom of the lower straightening shaft are connected to the gearbox. The bottom of the lower straightening shaft extends into the mounting base. A first transmission gear is rotatably connected to the lower straightening shaft, and a second transmission gear is rotatably connected to the lifting shaft. By adjusting the height of the first shaft portion, the first transmission gear can mesh with the first upper shackle gear sleeve, or the second transmission gear can mesh with the second upper shackle gear sleeve.

[0018] The second shaft is rotatably connected to the gearbox. The second shaft includes an upper gear shaft, a worm gear shaft, and a lower gear shaft connected in sequence. An upper gear is fixedly connected to the upper gear shaft, and a lower gear is fixedly connected to the lower gear shaft. A worm gear is connected to the worm gear shaft, and a worm is connected to the worm gear. The worm is detachably connected to a second handle.

[0019] A further improvement of the variable diameter wellhead device for a plunger gas lift well of the present invention is that a lifting chamber is provided at the top of the gearbox, the top of the lifting shaft passes through the lifting chamber and extends out from the top of the lifting chamber, and a lower lifting nut and an upper locking nut are screwed to the end of the lifting shaft extending out of the lifting chamber, and a limiting part is provided on the lifting shaft corresponding to the position of the lifting chamber.

[0020] A further improvement of the variable diameter wellhead device for a plunger gas lift well of the present invention is that a first bushing is provided between the lower centralizing shaft and the first transmission gear, a second bushing is provided between the lifting shaft and the second transmission gear, the bottom end of the lower gear shaft is connected to the gearbox through a sliding bearing, and the top end of the upper gear shaft is connected to the gearbox through a bearing seat and a roller bearing.

[0021] A further improvement of the variable diameter wellhead device for a plunger gas lift well according to the present invention is that the variable diameter core tube includes a first section and a second section. The outer diameter of the first section matches the top outer diameter of the wellhead tree main tube. The first upper shackle gear sleeve is connected to the top of the wellhead tree main tube and the first section. The outer diameter of the second section is smaller than the inner diameter of the wellhead tree main tube. The second section is inserted into the wellhead tree main tube and the tubular tree structure of the plunger gas lift well. The bottom end of the inner diameter of the second section forms a fluid guiding surface with a slope of 4°.

[0022] This invention discloses a variable-diameter wellhead device for a plunger gas lift well. A drive assembly is installed on the side of the wellhead tree main pipe, and a drive section is installed on the side of the variable-diameter core tube. The drive assembly controls the drive section to move the variable-diameter core tube up and down along the wellhead tree main pipe. When the variable-diameter core tube is placed inside the wellhead tree main pipe, the inner diameter of the gas tree becomes the inner diameter of the variable-diameter core tube, matching the plunger size with the inner diameter of the gas tree. This prevents gas from rising below the plunger and improves the production efficiency of the produced fluid. A buffer is installed at the top of the variable-diameter core tube to provide a buffering force during upward thrust, preventing damage to the variable-diameter core tube from external factors. A shackle device facilitates the installation and removal of the first upper shackle gear sleeve between the variable-diameter core tube and the wellhead tree main pipe, and the second upper shackle gear sleeve between the variable-diameter core tube and the buffer connector. This improves the assembly efficiency between the variable-diameter core tube and the wellhead tree main pipe, as well as between the variable-diameter core tube and the buffer, and facilitates rapid diameter reduction operations on the wellhead tree main pipe, thus improving work efficiency.

[0023] Additional aspects and advantages of the invention will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. Attached Figure Description

[0024] To more clearly illustrate the technical solutions in this invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of this invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0025] Figure 1 This is a schematic diagram of a variable diameter wellhead device for a plunger gas lift well provided by the present invention. Figure 1 .

[0026] Figure 2 This is a schematic diagram of the drive assembly in a variable-diameter wellhead device for a plunger gas lift well provided by the present invention.

[0027] Figure 3 This is a schematic diagram of a variable diameter wellhead device for a plunger gas lift well provided by the present invention. Figure 2 .

[0028] Figure 4 This is a schematic diagram of the uncoupling device in a variable diameter wellhead device for a plunger gas lift well provided by the present invention.

[0029] Figure 5 This is a schematic diagram of the installation and removal of the second upper shackle gear sleeve in the shackle device of a variable diameter wellhead equipment for a plunger gas lift well provided by the present invention.

[0030] Figure 6 This is a schematic diagram of the installation and removal of the first upper shackle gear sleeve in the shackle device of a variable diameter wellhead device for a plunger gas lift well provided by the present invention.

[0031] Figure 7 This is a schematic diagram of the assembly of a variable diameter wellhead device for a plunger gas lift well provided by the present invention.

[0032] Figure label:

[0033] 1. Shackle device; 2. Gear seat; 3. Drive gear; 4. Drive gear shaft; 5. Buffer; 6. Buffer connector; 7. Second upper shackle gear sleeve; 8. Variable diameter core tube; 81. Rack; 9. First upper shackle gear sleeve; 10. Sealing ring; 11. Wellhead tree main pipe; 12. Gas lift wellhead horizontal pipe; 13. Second handle; 14. First handle; 15. Plunger catcher; 101. Upper locking nut; 102. Lifting chamber; 103. Lifting shaft ; 104. Second bushing; 105. Second transmission gear; 106. Central shaft; 107. First transmission gear; 108. Lower centering shaft; 109. Mounting base; 110. Sliding bearing; 111. Lower gear shaft; 112. Gearbox; 113. Lower gear; 114. Worm gear shaft; 115. Worm; 116. Worm gear; 117. Upper gear; 118. Upper gear shaft; 119. Bearing housing; 120. Roller bearing; 121. Bearing cover. Detailed Implementation

[0034] To make the objectives, technical solutions, and advantages of this invention clearer, the technical solutions of this invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of this invention. All other embodiments obtained by those skilled in the art based on the embodiments of this invention without creative effort are within the scope of protection of this invention. The following embodiments are used to illustrate this invention but should not be used to limit the scope of this invention.

[0035] The following is combined Figure 1 This invention describes a variable diameter wellhead device for a plunger gas lift well. The wellhead of the plunger gas lift well is provided with a wellhead tree main pipe 11. The variable diameter wellhead device includes: a variable diameter core tube 8, which is inserted into the wellhead tree main pipe 11. A first through hole is opened on the side of the wellhead tree main pipe 11. A drive section is provided on the side of the variable diameter core tube 8 along the height direction. A drive assembly is provided on the side of the wellhead tree main pipe 11 corresponding to the first through hole. The drive assembly is driven and connected to the drive section. The top of the outer side wall of the variable diameter core tube 8 and the wellhead tree main pipe 11 are connected by a first upper uncoupling gear sleeve 9; and a uncoupling device 1, which is provided on the side of the variable diameter core tube 8 and is used to load and unload the first upper uncoupling gear sleeve 9.

[0036] In a preferred embodiment of the present invention, a variable diameter wellhead device for a plunger gas lift well is provided, such as... Figure 1 and Figure 2 As shown, the drive section is a rack 81 formed on the side of the variable diameter core tube 8; the drive assembly includes a gear seat 2 installed on the outer wall of the wellhead tree main tube 11 corresponding to the first through hole and a drive gear 3 rotatably connected to the gear seat 2. The drive gear 3 meshes with the rack 81. The drive gear 3 is connected to a drive gear shaft 4. The drive gear shaft 4 is connected to a first handle 14.

[0037] By having the operator rotate the first handle 14, the drive gear shaft 4 is rotated, which in turn drives the drive gear 3 to rotate, which in turn drives the rack 81 to move along the height direction, thereby driving the variable diameter core tube 8 to move along the axial direction of the wellhead tree main tube 11. This facilitates the installation or removal of the variable diameter core tube 8 into or from the wellhead tree main tube 11, thereby changing the inner diameter of the gas production tree tube so that the inner diameter of the plunger and the gas production tree tube are matched.

[0038] Preferably, the drive gear shaft 4 can also be connected to a drive motor to achieve fully automatic drive, further improving the assembly efficiency of the variable diameter core tube 8 and the wellhead tree main tube 11.

[0039] Preferably, a reinforcing portion is formed on the wellhead tree main pipe 11 corresponding to the position of the first through hole to increase the structural strength of the wellhead tree main pipe 11 at the first through hole, so as to prevent the wellhead tree main pipe 11 from being deformed or damaged due to excessive force during the assembly or disassembly of the drive assembly. The reinforcing portion can be set as annular or block-shaped, and the reinforcing portion and the wellhead tree main pipe 11 are integrally formed to improve the durability and service life of the wellhead tree main pipe 11, while reducing the risk of equipment damage due to improper operation.

[0040] Preferably, a sealing ring 10 is provided between the wellhead tree main pipe 11 and the variable diameter core pipe 8. The sealing ring 10 is a sealing O-ring, and multiple sealing rings 10 are provided at intervals along the axial direction. The sealing ring 10 is located above the drive assembly to improve the sealing performance between the wellhead tree main pipe 11 and the variable diameter core pipe 8.

[0041] Furthermore, such as Figure 1 As shown, the top end of the reducing core tube 8 is connected to a buffer 5 via a buffer connector 6. The buffer 5 includes a buffer cap and a buffer spring. The buffer cap is located at the top end of the reducing core tube 8 and is used to absorb the impact force of the reducing core tube 8 during assembly or operation, protecting the reducing core tube 8 and the wellhead tree main tube 11 from damage. The buffer spring is located between the buffer cap and the reducing core tube 8. When the reducing core tube 8 is subjected to an impact force, the buffer spring can undergo elastic deformation, thereby absorbing and dispersing the impact force, further protecting the reducing core tube 8 and the wellhead tree main tube 11. The buffer connector 6 enables the reducing core tube 8 to operate smoothly and safely during assembly or operation, improving the stability and reliability of the equipment.

[0042] Furthermore, such as Figure 4 , Figure 5 and Figure 6As shown, the outer walls of the buffer connector 6 and the variable diameter core tube 8 are connected by the second upper shackle gear sleeve 7. The second upper shackle gear sleeve 7 is driven to be connected to the shackle device 1. The shackle device 1 drives the second upper shackle gear sleeve 7 to rotate, so that the second upper shackle gear sleeve 7 is connected to the connection between the buffer connector 6 and the variable diameter core tube 8, thereby preventing the buffer connector 6 and the variable diameter core tube 8 from separating.

[0043] Furthermore, such as Figure 4 , Figure 5 and Figure 6 As shown, the shackle device 1 includes: a mounting base 109; a gearbox 112, the gearbox 112 being fixed to the top of the mounting base 109;

[0044] The first shaft is height-adjustable and connected to the gearbox 112. The first shaft includes a lifting shaft 103, a central shaft 106, and a lower straightening shaft 108 connected in sequence. The top of the lifting shaft 103 and the bottom of the lower straightening shaft 108 are connected to the gearbox 112. The bottom of the lower straightening shaft 108 extends into the mounting base 109. A first transmission gear 107 is rotatably connected to the lower straightening shaft 108, and a second transmission gear 105 is rotatably connected to the lifting shaft 103. By adjusting the height of the first shaft, the first transmission gear 107 can mesh with the first upper shackle gear sleeve 9, or the second transmission gear 105 can mesh with the second upper shackle gear sleeve 7.

[0045] The second shaft is rotatably connected to the gearbox 112. The second shaft includes an upper gear shaft 118, a worm gear shaft 114, and a lower gear shaft 111 connected in sequence. An upper gear 117 is fixedly connected to the upper gear shaft 118, a lower gear 113 is fixedly connected to the lower gear shaft 111, a worm gear 116 is connected to the worm gear shaft 114, and a worm 115 is connected to the worm gear 116. A second handle 13 is detachably connected to the worm 115.

[0046] Specifically, such as Figure 4 , Figure 5 and Figure 6 As shown, a lifting chamber 102 is provided on the top of the gearbox 112. The top of the lifting shaft 103 passes through the lifting chamber 102 and extends out from the top of the lifting chamber 102. The end of the lifting shaft 103 extending out of the lifting chamber 102 is screwed with a lower lifting nut and an upper locking nut 101. A limiting part is provided on the lifting shaft 103 corresponding to the position of the lifting chamber 102.

[0047] Better, such as Figure 5As shown, by screwing on the lower lifting nut, the height of the first shaft is changed, thereby causing the first transmission gear 107 to mesh between the first upper shackle gear sleeve 9 and the lower gear 113. Then, the second handle 13 is rotated to drive the worm 115, worm wheel 116, and turbine shaft to rotate, thereby driving the lower gear 113 to rotate, which in turn drives the first transmission gear 107 to rotate, which in turn drives the first upper shackle gear sleeve 9 to rotate. This causes the first upper shackle gear sleeve 9 to rotate along the outer diameter of the variable diameter core tube 8 and the wellhead tree main tube 11, thereby screwing the first upper shackle gear sleeve 9 into the connection between the variable diameter core tube 8 and the wellhead tree main tube 11 to fix the connection between the variable diameter core tube 8 and the wellhead tree main tube 11.

[0048] Better, such as Figure 6 As shown, by tightening the lower lifting nut, the height of the first shaft is changed, causing the second transmission gear 105 to mesh between the second upper shackle gear sleeve 7 and the upper gear 117. Then, the second handle 13 is rotated to drive the worm 115, worm wheel 116, and turbine shaft to rotate, thereby driving the upper gear 117 to rotate, which in turn drives the second transmission gear 105 to rotate, which in turn drives the second upper shackle gear sleeve 7 to rotate. This causes the second upper shackle gear sleeve 7 to rotate along the outer diameter of the variable diameter core tube 8 and the buffer connector 6, so that the second upper shackle gear sleeve 7 is screwed onto the connection between the variable diameter core tube 8 and the buffer connector 6 to fix the connection between the variable diameter core tube 8 and the buffer connector 6.

[0049] Specifically, such as Figure 4 As shown, a first bushing is provided between the lower centering shaft 108 and the first transmission gear 107, and a second bushing 104 is provided between the lifting shaft 103 and the second transmission gear 105. The bottom end of the lower gear shaft 111 and the gearbox 112 are connected by a sliding bearing 110, and the top end of the upper gear shaft 118 and the gearbox 112 are connected by a bearing seat 119 and a roller bearing 120. A bearing cover 121 is provided on the top of the roller bearing 120.

[0050] Specifically, the variable diameter core tube 8 includes a first section and a second section. The outer diameter of the first section matches the top outer diameter of the wellhead tree main tube 11. The first upper shackle gear sleeve 9 is connected to the top of the wellhead tree main tube 11 and the first section. The outer diameter of the second section is smaller than the inner diameter of the wellhead tree main tube 11. The second section is inserted into the wellhead tree main tube 11 and the plunger gas lift well tubular tree structure. The outer diameter of the first section is larger than the outer diameter of the second section to prevent the variable diameter core tube 8 from falling into the gas production tree due to gravity, thereby improving the connection stability between the variable diameter core tube 8 and the wellhead tree main tube 11.

[0051] Preferably, the bottom of the inner diameter of the second pipe section has a liquid guiding surface with a slope of 4°, so that the gas in the gas-collecting tree can smoothly enter the variable diameter core tube 8, reduce the stress surface of the pipe wall thickness of the variable diameter core tube 8, prevent the variable diameter core tube 8 from moving upward under force, and improve the connection stability of the variable diameter core tube 8.

[0052] Preferably, the wellhead tree main pipe 11 is connected to the gas lift wellhead horizontal pipe 12 and the plunger catcher 15. The variable diameter core pipe 8 can be provided with a second through hole at the position corresponding to the gas lift wellhead horizontal pipe 12, and the variable diameter core pipe 8 can be provided with a third through hole at the position corresponding to the plunger catcher 15.

[0053] Preferably, the first section of the variable diameter core tube 8 has threads, the top outer wall of the wellhead tree main tube 11 has threads, and the buffer connector 6 has threads on the outside to facilitate connection of the first upper shackle gear sleeve 9 and the second upper shackle gear sleeve 7.

[0054] In a specific implementation case, such as Figure 3 and Figure 7 As shown, when it is necessary to change the inner diameter of the main pipe 11 of the wellhead tree, the operator rotates the first handle 14 to drive the drive gear shaft 4 to rotate, thereby driving the drive gear 3 to rotate, which in turn drives the rack 81 to move along the height direction, thereby driving the variable diameter core tube 8 to move along the axial direction of the main pipe 11 of the wellhead tree, so that the variable diameter core tube 8 can be easily installed into or removed from the main pipe 11 of the wellhead tree, so that the second pipe section is completely inserted into the main pipe 11 of the wellhead tree, and the bottom end of the first pipe section abuts against the top end of the main pipe 11 of the wellhead tree.

[0055] By turning the lower lifting nut, the height of the first shaft is changed, so that the first transmission gear 107 meshes between the first upper shackle gear sleeve 9 and the lower gear 113. Then, the second handle 13 is turned to drive the worm 115, worm wheel 116 and turbine shaft to rotate, thereby driving the lower gear 113 to rotate, thereby driving the first transmission gear 107 to rotate, thereby driving the first upper shackle gear sleeve 9 to rotate, thereby driving the first upper shackle gear sleeve 9 to rotate along the outer diameter of the variable diameter core tube 8 and the wellhead tree main tube 11, so that the first upper shackle gear sleeve 9 is screwed into the connection between the variable diameter core tube 8 and the wellhead tree main tube 11 to fix the connection between the variable diameter core tube 8 and the wellhead tree main tube 11.

[0056] The buffer 5 is connected to the variable diameter core tube 8 via the buffer connector 6. By tightening the lower lifting nut, the height of the first shaft is changed, causing the second transmission gear 105 to mesh between the second upper shackle gear sleeve 7 and the upper gear 117. Then, the second handle 13 is rotated to drive the worm 115, worm wheel 116, and turbine shaft to rotate, thereby driving the upper gear 117 to rotate, which in turn drives the second transmission gear 105 to rotate, which in turn drives the second upper shackle gear sleeve 7 to rotate. This causes the second upper shackle gear sleeve 7 to rotate along the outer diameter of the variable diameter core tube 8 and the buffer connector 6, so that the second upper shackle gear sleeve 7 is screwed into the connection between the variable diameter core tube 8 and the buffer connector 6 to fix the connection between the variable diameter core tube 8 and the buffer connector 6.

[0057] This invention discloses a variable-diameter wellhead device for a plunger gas lift well. A drive assembly is installed on the side of the wellhead tree main pipe 11, and a drive section is installed on the side of the variable-diameter core tube 8. The drive assembly controls the drive section to move the variable-diameter core tube 8 up and down along the wellhead tree main pipe 11. When the variable-diameter core tube 8 is placed inside the wellhead tree main pipe 11, the inner diameter of the gas tree becomes the inner diameter of the variable-diameter core tube 8, ensuring that the plunger size matches the inner diameter of the gas tree. This prevents gas from rising below the plunger and improves the production efficiency of the produced fluid. Through the variable-diameter... A buffer 5 is provided at the top of the core tube 8 to provide a buffering force when the variable diameter core tube 8 is thrust upward, preventing the variable diameter core tube 8 from being damaged by external factors. By setting a shackle device 1, it is convenient to install and remove the first upper shackle gear sleeve 9 between the variable diameter core tube 8 and the wellhead tree main tube 11 and the second upper shackle gear sleeve 7 between the variable diameter core tube 8 and the buffer connector 6, which improves the assembly efficiency between the variable diameter core tube 8 and the wellhead tree main tube 11 and between the variable diameter core tube 8 and the buffer 5, and facilitates the quick diameter change operation of the wellhead tree main tube 11, thereby improving work efficiency.

[0058] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A variable-diameter wellhead device for a plunger gas lift well, wherein the wellhead of the plunger gas lift well is equipped with a wellhead tree main pipe, characterized in that, The variable diameter wellhead equipment includes: A variable diameter core tube is inserted into the wellhead tree main tube. A first through hole is provided on the side of the wellhead tree main tube. A drive section is provided on the side of the variable diameter core tube along the height direction. A drive assembly is provided on the side of the wellhead tree main tube corresponding to the first through hole. The drive assembly is drivenly connected to the drive section. The top of the outer side wall of the variable diameter core tube and the wellhead tree main tube are connected by a first upper shackle gear sleeve. A shackle device is provided on the side of the variable diameter core tube, and the shackle device is used to install and remove the first upper shackle gear sleeve; The top end of the variable diameter core tube is connected to a buffer via a buffer connector, and the buffer includes a buffer cap and a buffer spring. The buffer connector and the outer wall of the variable diameter core tube are connected by a second upper shackle gear sleeve, which is driven to the shackle device. The unhooking device includes: Mounting base; A gearbox, the gearbox being fixed to the top of the mounting base; A first shaft portion, the first shaft portion being height-adjustable and connected to the gearbox, the first shaft portion including a lifting shaft, a central shaft and a lower straightening shaft connected in sequence, the top of the lifting shaft and the bottom of the lower straightening shaft being connected to the gearbox, the bottom of the lower straightening shaft extending into the mounting base, a first transmission gear being rotatably connected to the lower straightening shaft, and a second transmission gear being rotatably connected to the lifting shaft; The second shaft is rotatably connected to the gearbox. The second shaft includes an upper gear shaft, a worm gear shaft, and a lower gear shaft connected in sequence. An upper gear is fixedly connected to the upper gear shaft, and a lower gear is fixedly connected to the lower gear shaft. A worm gear is connected to the worm gear shaft, and a worm is connected to the worm gear. The worm is detachably connected to a second handle. By changing the height of the first shaft, the first transmission gear can mesh between the first upper shackle gear sleeve and the lower gear, or the second transmission gear can mesh between the second upper shackle gear sleeve and the upper gear.

2. The variable diameter wellhead device for a plunger gas lift well according to claim 1, characterized in that, The drive section is a rack formed on the side of the variable diameter core tube; The drive assembly includes a gear seat mounted on the outer wall of the main wellhead corresponding to the first through hole and a drive gear rotatably connected to the gear seat. The drive gear meshes with the rack, and the drive gear is connected to a drive gear shaft, which is connected to a first handle.

3. The variable diameter wellhead device for a plunger gas lift well according to claim 1, characterized in that, The wellhead tree main pipe has a reinforcing section formed at the position corresponding to the first through hole.

4. The variable diameter wellhead device for a plunger gas lift well according to claim 1, characterized in that, A sealing ring is provided between the wellhead tree main tube and the variable diameter core tube.

5. The variable diameter wellhead device for a plunger gas lift well according to claim 1, characterized in that, The gearbox has a lifting chamber at its top. The top of the lifting shaft passes through the lifting chamber and extends out from the top of the lifting chamber. The end of the lifting shaft extending out of the lifting chamber is screwed with a lower lifting nut and an upper locking nut. The lifting shaft has a limiting part corresponding to the position of the lifting chamber.

6. The variable diameter wellhead device for a plunger gas lift well according to claim 5, characterized in that, A first bushing is provided between the lower centering shaft and the first transmission gear, and a second bushing is provided between the lifting shaft and the second transmission gear. The bottom end of the lower gear shaft is connected to the gearbox via a sliding bearing, and the top end of the upper gear shaft is connected to the gearbox via a bearing seat and a roller bearing.

7. The variable diameter wellhead device for a plunger gas lift well according to claim 1, characterized in that, The variable diameter core tube includes a first section and a second section. The outer diameter of the first section matches the top outer diameter of the wellhead tree main tube. The first upper shackle gear sleeve is connected to the top of the wellhead tree main tube and the first section. The outer diameter of the second section is smaller than the inner diameter of the wellhead tree main tube. The second section is inserted into the wellhead tree main tube and the plunger gas lift well tubular tree structure. The bottom of the inner diameter of the second section forms a fluid guiding surface with a slope of 4°.

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