Step-by-step plunger gas lift lock collar

Abstract

The present application relates to the technical field of oil and gas reservoir drainage gas recovery, and particularly relates to a kind of plunger step-by-step gas lift with locking device, aiming at solving the technical problem that the existing locking device cannot be applied in step-by-step plunger gas lift. The plunger step-by-step gas lift with locking device can withstand the impact of both lower plunger and upper plunger. The single-flow valve arranged in the central pipe prevents the fluid carried by the lower plunger from slipping off the locking device. In addition, the upper plunger can only be started when the lower plunger reaches the locking device position, i.e. the lower plunger lifts all the fluid to the upper part of the locking device, and the upper plunger can work, ensuring the normal production of the gas well.

Description

Technical Field

[0001] This invention relates to the field of oil and gas reservoir drainage and gas production technology, and in particular to a plunger staged gas lift locking device. Background Technology

[0002] Plunger gas lift drainage gas production technology is one of the main technologies for stable gas well production. However, as the gas well continues to produce, the bottom hole pressure will gradually decrease, and the fluid accumulation will become more and more serious. When using a single-stage plunger, insufficient pressure in the well will prevent the plunger from reaching the wellhead, making it impossible to drain the fluid, resulting in process failure and the gas well being unable to produce normally. Therefore, it is necessary to install multiple plunger holders in the well to perform plunger-stage gas lift.

[0003] The current locking devices used in single-stage plunger gas lift can only withstand the unidirectional impact of the plunger, and do not take into account the problem of liquid slippage. Therefore, they cannot be used in stage-by-stage plunger gas lift. Summary of the Invention

[0004] The purpose of this invention is to provide a locking device for a plunger staged gas lift, so as to solve the technical problem that existing locking devices cannot be applied in staged plunger gas lift.

[0005] To solve the above-mentioned technical problems, the technical solution provided by the present invention is as follows:

[0006] The plunger staged gas lift locking device provided by the present invention includes: a central tube and a release head;

[0007] A flow valve is installed inside the central tube;

[0008] The drop head is fitted onto one end of the central tube and connected to the central tube via drop scissor pins;

[0009] From the first end of the dropper tube to the other end of the central tube, the central tube is sequentially fitted with an upper shock-absorbing assembly, a seat-hanging assembly, a seat-sealing assembly, and a lower shock-absorbing assembly;

[0010] The upper shock absorption assembly includes an upper core tube, an upper shock absorption ring, and an upper shock absorption spring; the seat suspension assembly includes an upper support sleeve.

[0011] The upper tube is sleeved on the central tube;

[0012] The upper shock-absorbing ring is sleeved on the central tube and threadedly connected to the end of the upper central tube near the dropper head;

[0013] The upper support sleeve includes a limiting section, which is sleeved on the upper core tube and can slide along the axial direction of the upper core tube between the upper damping ring and the end of the upper core tube away from the upper damping ring.

[0014] The upper damping spring is sleeved on the upper core tube and is located between the upper damping ring and the upper support sleeve. One end of the spring is fixedly connected to the upper damping ring, and the other end is fixedly connected to the upper support sleeve.

[0015] The seat assembly includes a lower connector, and the lower damping assembly includes a lower damping ring and a lower damping spring;

[0016] The lower shock-absorbing ring is sleeved on the other end of the central tube and connected to the central tube by a fixing shear pin;

[0017] The lower damping spring is sleeved on the central tube and abuts between the lower damping ring and the lower connector, with one end fixedly connected to the lower damping ring and the other end fixedly connected to the lower connector.

[0018] Furthermore, the upper support sleeve also includes a seat section extending out of the upper core tube, the outer wall of the seat section is provided with a protrusion, and the inner wall opposite the protrusion is provided with a groove.

[0019] The seat assembly also includes a locking block and an open retaining ring disposed between the seat section and the central tube;

[0020] The locking block is fixed to the outer wall of the central tube and is located between the groove and the upper central tube. A limiting groove is provided on the surface of the locking block opposite to the seat section.

[0021] The open retaining ring is sleeved on the locking block and embedded in the limiting groove, and abuts against the inner wall of the seat hanging section.

[0022] Furthermore, the outer wall of the central tube is provided with a first protrusion, and the locking block is connected to the first protrusion by a limiting shear pin.

[0023] Furthermore, the seat assembly also includes a lower core tube;

[0024] The lower core tube is sleeved on the central tube and forms a flow channel between them. The lower core tube is provided with a pressure transmission hole that penetrates its side wall.

[0025] The outer wall of the central tube is also provided with a second protrusion, which is directly opposite the pressure transmission hole and is sealed to the inner wall of the lower central tube.

[0026] Along the axial direction of the lower core tube, an unsealing component, a rubber sleeve, and a sliding component are sequentially fitted onto the lower core tube;

[0027] The unsealing component is fixedly connected to the seat hanging section and is also connected to the lower core tube by a fixed C-shaped ring;

[0028] The sliding component and the lower core tube form an annular cavity, which is connected to the pressure transmission hole;

[0029] The lower connector is sleeved on the lower core tube and threadedly connected to the lower core tube to support the sliding assembly.

[0030] Furthermore, the inner wall of the lower core tube is embedded with two sealing rings, which are located on both sides of the pressure transmission hole and abut against the second boss.

[0031] Furthermore, a locking sleeve is also fitted on the lower core tube. The locking sleeve is threadedly connected to the lower core tube and is located within the space formed by the lower connector, the lower core tube, and the sliding assembly.

[0032] The sliding assembly includes a pressure cap and a C-shaped locking ring;

[0033] The pressure cap is fitted onto the locking sleeve;

[0034] The C-shaped locking ring is disposed between the lower pressure cap and the locking sleeve, and is embedded in the lower pressure cap. It is also connected to the locking sleeve by a toothed buckle.

[0035] Furthermore, the unsealing component includes a fixing sleeve, an unsealing connecting sleeve, and an unsealing sleeve;

[0036] The fixing sleeve is located between the lower core tube and the seat section, and is threadedly connected to the seat section;

[0037] The inner wall of the seat section away from the groove is provided with a sliding groove, which extends along the axial direction of the seat section.

[0038] The unsealing connecting sleeve is fitted onto the fixed sleeve, and an unsealing C-shaped ring is embedded on its outer wall. The unsealing C-shaped ring is located in the sliding groove and can slide along the extension direction of the sliding groove.

[0039] The unsealing sleeve is located within the space formed by the lower core tube, the fixing sleeve, and the unsealing connecting sleeve, and is connected to the lower core tube through the fixing C-ring, and also connected to the fixing sleeve through the unsealing shear pin.

[0040] Furthermore, the unsealing sleeve includes an integrally formed connecting section and segmented claws;

[0041] The diameter of the connecting segment is smaller than the diameter of the segmented claw;

[0042] The segmented claw forms a step with the connecting section and is connected to the fixing sleeve by the unsealing screw;

[0043] The inner wall of the unsealing connecting sleeve protrudes to form a locking platform, which contacts the outer wall of the connecting segment and also contacts the stepped surface between the split locking claw and the connecting segment.

[0044] Furthermore, the upper shock absorber assembly also includes a limiting sleeve, which is sleeved on the upper core tube and threadedly connected to the upper core tube;

[0045] The limiting segment is connected between the limiting sleeve and the upper shock-absorbing spring.

[0046] Furthermore, the central tube is a barrel shape with one end open and the other end closed, and multiple flow holes are provided on the side wall on which the lower shock-absorbing spring is sleeved.

[0047] The lower shock-absorbing ring is inserted into the closed end of the central tube, and its sidewall is connected to the central tube through the fixing screw.

[0048] In summary, the technical effects achieved by the plunger staged gas lift locking device provided by this invention are as follows:

[0049] In this plunger-stage air lift retainer, the upper damping ring is used to connect with the upper plunger. When subjected to pressure from the upper plunger, the upper damping ring will compress the upper damping spring. When the lower plunger carries the accumulated liquid upward, the accumulated liquid will enter the central tube, and the presence of the check valve prevents the accumulated liquid from falling back. When the lower plunger reaches the lower damping ring, it will push the lower damping ring and the central tube to move, thereby compressing the lower damping spring. At the same time, during the movement, the central tube will push the upper plunger connected to the upper damping ring, causing the upper plunger to disengage from the upper damping ring and start the air lift operation.

[0050] It can be seen that, compared with the existing technology, the plunger stage gas lift clamp can withstand the impact of both the lower and upper stage plungers; the one-way valve installed in the central pipe prevents the liquid carried by the lower stage plunger from slipping off the clamp; in addition, the upper stage plunger can only start when the lower stage plunger reaches the clamp position, that is, the lower stage plunger lifts all the liquid to the top of the clamp before the upper stage plunger can work, thus ensuring the normal production of the gas well. Attached Figure Description

[0051] To more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0052] Figure 1This is a cross-sectional view of a plunger staged gas lift locking device provided in an embodiment of the present invention;

[0053] Figures 2 to 4 for Figure 1 Sectional views of different segments from top to bottom;

[0054] Figure 5 This is a cross-sectional view of the plunger staged gas lift locking device after setting, provided in an embodiment of the present invention.

[0055] Figures 6 to 8 for Figure 5 Sectional views of different segments from top to bottom;

[0056] Figure 9 This is a cross-sectional view of the plunger stage gas lift locking device after unsealing, provided in an embodiment of the present invention.

[0057] Figures 10 to 12 for Figure 9 Sectional views of different segments from top to bottom.

[0058] Icons: 1-Center tube; 2-Discarding shear pin; 3-Check valve; 4-Discarding shear pin; 5-Upper core tube; 6-Upper damping ring; 7-Upper damping spring; 8-Upper support sleeve; 9-Lower connector; 10-Lower damping ring; 11-Lower damping spring; 12-Fixing shear pin; 13-Protrusion; 14-Groove; 15-Locking block; 16-Open retaining ring; 17-First boss; 18-Limiting shear pin; 19-Lower core tube; 20-Pressure transmission hole; 21-Second boss ; 22-Glue Sleeve; 23-Fixing C-ring; 24-Sealing Ring; 25-Locking Sleeve; 26-Lowering Cap; 27-C-locking Ring; 28-Fixing Sleeve; 29-Unsealing Connecting Sleeve; 30-Unsealing Sleeve; 31-Unsealing C-ring; 32-Unsealing Shear Pin; 33-Limiting Sleeve; 34-Flow Hole; 35-Positioning Spring; 36-Positioning Ball; 37-Upper Glue Sleeve Seat; 38-Glue Sleeve Ring; 39-Balance Piston; 40-Lower Glue Sleeve Seat; 41-Limiting Ring. Detailed Implementation

[0059] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, 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. The components of the embodiments of the present invention described and shown in the accompanying drawings can generally be arranged and designed in various different configurations.

[0060] Therefore, the following detailed description of the embodiments of the invention provided in the accompanying drawings is not intended to limit the scope of the claimed invention, but merely to illustrate selected embodiments of the invention. All other embodiments obtained by those skilled in the art based on the embodiments of the invention without inventive effort are within the scope of protection of the invention.

[0061] The following detailed description of some embodiments of the present invention is provided in conjunction with the accompanying drawings. Unless otherwise specified, the following embodiments and features can be combined with each other.

[0062] The locking devices currently used for single-stage plunger gas lift can only withstand the unidirectional impact of the plunger, and do not take into account the problem of liquid slippage. Therefore, they cannot be used in stage-by-stage plunger gas lift.

[0063] In view of this, the present invention provides a locking device for a plunger staged gas lift, comprising a central tube 1 and a release head 2; a one-way valve 3 is provided inside the central tube 1; the release head 2 is sleeved on one end of the central tube 1 and connected to the central tube 1 by a release shear pin 4; from the release head 2 to the other end of the central tube 1, an upper shock-absorbing assembly, a seat assembly, a seat seal assembly, and a lower shock-absorbing assembly are sequentially sleeved on the central tube 1; the upper shock-absorbing assembly includes an upper core tube 5, an upper shock-absorbing ring 6, and an upper shock-absorbing spring 7, and the seat assembly includes an upper support sleeve 8; the upper core tube 5 is sleeved on the central tube 1; the upper shock-absorbing ring 6 is sleeved on the central tube 1 and threadedly connected to the end of the upper core tube 5 near the release head 2; the upper support sleeve 8 includes a limiting section, which is sleeved on the upper core tube 1. The upper tube 5 can slide along the axial direction of the upper tube 5 between the upper shock-absorbing ring 6 and the end of the upper tube 5 away from the upper shock-absorbing ring 6; the upper shock-absorbing spring 7 is sleeved on the upper tube 5 and is located between the upper shock-absorbing ring 6 and the upper support sleeve 8, with one end fixedly connected to the upper shock-absorbing ring 6 and the other end fixedly connected to the upper support sleeve 8; the setting assembly includes a lower connector 9, and the lower shock-absorbing assembly includes a lower shock-absorbing ring 10 and a lower shock-absorbing spring 11; the lower shock-absorbing ring 10 is sleeved on the other end of the central tube 1 and is connected to the central tube 1 by a fixing shear pin 12; the lower shock-absorbing spring 11 is sleeved on the central tube 1 and abuts against the lower shock-absorbing ring 10 and the lower connector 9, with one end fixedly connected to the lower shock-absorbing ring 10 and the other end fixedly connected to the lower connector 9.

[0064] In this plunger-stage air lift retainer, the upper damping ring 6 is used to connect with the upper plunger. When subjected to pressure from the upper plunger, the upper damping ring 6 will compress the upper damping spring 7. When the lower plunger carries the accumulated liquid upward, the accumulated liquid will enter the central tube 1, and the presence of the one-way valve 3 prevents the accumulated liquid from falling back. When the lower plunger reaches the lower damping ring 10, it will push the lower damping ring 10 and the central tube 1 to move, thereby compressing the lower damping spring 11. At the same time, during the movement, the central tube 1 will push the upper plunger connected to the upper damping ring 6, causing the upper plunger to disengage from the upper damping ring 6 and start the air lift operation.

[0065] It can be seen that, compared with the existing technology, the plunger stage gas lift clamp can withstand the impact of both the lower and upper stage plungers; the one-way valve 3 installed in the central pipe 1 prevents the liquid carried by the lower stage plunger from slipping off the clamp; in addition, the upper stage plunger can only start when the lower stage plunger reaches the clamp position, that is, the lower stage plunger lifts all the liquid to the upper part of the clamp, and the upper stage plunger can work, thus ensuring the normal production of the gas well.

[0066] The following combination Figures 1 to 12 The structure and shape of the plunger staged gas lift clamp provided in this embodiment are described in detail:

[0067] Further reference Figure 1 and Figure 2 The upper support sleeve 8 also includes a seat hanging section extending out of the upper core tube 5. The outer wall of the seat hanging section is provided with a protrusion 13, and the inner wall opposite to the protrusion 13 is provided with a groove 14. The seat hanging assembly also includes a locking block 15 and an open retaining ring 16 disposed between the seat hanging section and the core tube 1. The locking block 15 is connected to the outer wall of the core tube 1 by a limiting shear pin 18 and is located between the groove 14 and the upper core tube 5. The locking block 15 is provided with a limiting groove on the surface opposite to the seat hanging section. The open retaining ring 16 is sleeved on the locking block 15 and embedded in the limiting groove, and abuts against the inner wall of the seat hanging section.

[0068] Specifically, with Figure 2 For example, in application, the plunger is lowered to the construction position using a staged air lift device. At this time, the protrusion 13 on the upper support sleeve 8 is locked at the oil pipe coupling position. The release shear pin 4 is cut by the shock absorber. After the release shear pin 4 is cut, the central tube 1 loses its constraint and moves downward under the force of the lower damping spring 11 returning to its original position. During the downward movement, the central tube 1 drives the locking block 15, the open retaining ring 16, and the limiting shear pin 18 to move together. When the open retaining ring 16 reaches the groove 14 on the upper support sleeve 8, the open retaining ring 16 returns to its original position and locks the locking block 15 together, realizing the mounting of the device. Figure 5 and Figure 6 As shown.

[0069] Further reference Figure 3 and Figure 4The sealing assembly also includes a lower core tube 19; the lower core tube 19 is sleeved on the central tube 1 and forms a flow channel between them, and the lower core tube 19 is provided with a pressure transmission hole 20 penetrating its side wall; the outer wall of the central tube 1 is also provided with a second boss 21, which is directly opposite the pressure transmission hole 20 and is sealed to the inner wall of the lower core tube 19; along the axial direction of the lower core tube 19, a release component, a rubber sleeve 22 and a sliding component are sequentially sleeved on the lower core tube 19; the release component is fixedly connected to the seat section and is also snapped to the lower core tube 19 by a fixed C-ring 23; the sliding component and the lower core tube 19 form an annular cavity, which communicates with the pressure transmission hole 20; the lower connector 9 is sleeved on the lower core tube 19 and threadedly connected to the lower core tube 19 to support the sliding component.

[0070] For details, please refer to Figures 2 to 4 The outer wall of the central tube 1 is provided with a first protrusion 17, and the locking block 15 is connected to the first protrusion 17 by a limiting shear pin 18. Two sealing rings 24 are embedded in the inner wall of the lower central tube 19. The two sealing rings 24 are located on both sides of the pressure transmission hole 20 and abut against the second protrusion 21. (Reference) Figures 5 to 7 After the locking device is seated, the central tube 1 continues to move downwards, cutting off the limiting shear pin 18. At this time, the locking block 15 and the first boss 17 only abut against each other and do not move synchronously. During the downward movement of the central tube 1, the second boss 21 loses contact with the sealing ring 24, and the liquid in the oil pipe will enter the flow channel through the upper support sleeve 8, and then be transmitted to the annular cavity through the pressure transmission hole 20. Under the pressure of the liquid column, the sliding component will slide upwards, squeezing the rubber sleeve 22 to complete the seating of the locking device.

[0071] Further reference Figure 3 A locking sleeve 25 is also fitted on the lower core tube 19. The locking sleeve 25 is threadedly connected to the lower core tube 19 and is located within the space formed by the lower connector 9, the lower core tube 19, and the sliding assembly. The sliding assembly includes a lower pressure cap 26 and a C-shaped locking ring 27. The lower pressure cap 26 is fitted on the locking sleeve 25. The C-shaped locking ring 27 is located between the lower pressure cap 26 and the locking sleeve 25 and is embedded in the lower pressure cap 26. It is also connected to the locking sleeve 25 by a toothed buckle.

[0072] Specifically, when the sliding component slides upward, the lower cap 26 and the C-shaped locking ring 27 move upward. During the upward movement, the C-shaped locking ring 27 locks itself to the locking sleeve 25. This prevents the rubber sleeve 22 from springing back and ensures the effectiveness of the rubber sleeve 22 in setting.

[0073] Further reference Figure 3The unsealing assembly includes a fixed sleeve 28, an unsealing connecting sleeve 29, and an unsealing sleeve 30. The fixed sleeve 28 is located between the lower core tube 19 and the seat section and is threadedly connected to the seat section. The inner wall of the seat section away from the groove 14 is provided with a sliding groove, which extends along the axial direction of the seat section. The unsealing connecting sleeve 29 is sleeved on the fixed sleeve 28, and an unsealing C-shaped ring 31 is embedded on its outer wall. The unsealing C-shaped ring 31 is located in the sliding groove and can slide along the extension direction of the sliding groove. The unsealing sleeve 30 is located in the space formed by the lower core tube 19, the fixed sleeve 28, and the unsealing connecting sleeve 29, and is connected to the lower core tube 19 through the fixed C-shaped ring 23, and also connected to the fixed sleeve 28 through the unsealing shear pin 32.

[0074] Please continue to refer to this. Figure 3 The unsealing sleeve 30 includes an integrally formed connecting section and a split claw; the diameter of the connecting section is smaller than the diameter of the split claw; a step is formed between the split claw and the connecting section, and it is connected to the fixing sleeve 28 by the unsealing shear pin 32; the inner wall of the unsealing connecting sleeve 29 protrudes to form a locking platform, which contacts the outer wall of the connecting section and also contacts the stepped surface between the split claw and the connecting section.

[0075] refer to Figures 5 to 8 During the setting process, the fixing sleeve 28, the unsealing connecting sleeve 29, and the unsealing sleeve 30 are fixed to the upper support sleeve 8, cooperating with the sliding component to compress the rubber cylinder 22. When it is necessary to unseal the fixing device, the retrieval tool is lowered into the center, retrieved, and then the center tube 1 is lifted to cut the fixing shear pin 12, and then lifted further; (Refer to...) Figures 9 to 12 When the first protrusion 17 disengages from the locking block 15, the locking block 15 will be in an autonomous state. At this time, the upper split-type spring structure of the upper support sleeve 8 loses its support and is also in a free state. At this time, the central tube 1 continues to lift, which will drive the upper central tube 5 and the upper support sleeve 8 to move upward. During the upward movement of the upper support sleeve 8, the unsealing C-shaped ring 31 slides relative to the upper support sleeve 8 in the sliding groove, that is, the unsealing connecting sleeve 29 does not move, and the fixed sleeve 28 moves upward synchronously. During the upward movement of the fixed sleeve 28, the unsealing shear pin 32 is cut off. After the unsealing shear pin 32 is cut off, the split claw at the front end of the unsealing sleeve 30 loses its support and is in a free state. At this time, the unsealing connecting sleeve 29 loses the obstruction of the upper stepped surface of the unsealing sleeve 30 and moves upward under the drive of the upper support sleeve 8. In this way, the rubber sleeve 22 loses its limit and rebounds under its own elastic force, restoring its original shape, thereby completing the unsealing of the locking device.

[0076] refer to Figures 1 to 4In the plunger-stage gas lift locking device provided in this application embodiment, the release head 2 is fixed to the central tube 1 by the release shear pin 4. At the same time, the release head 2, the central tube 1, and the fixing shear pin 12 work together to limit the upper damping ring 6 and the lower damping ring 10, so that the lower damping spring 11 is in a compressed state in the initial state of the locking device; the positioning spring 35 and the positioning ball 36 are installed in the upper damping ring 6, and the upper damping ring 6 is connected to the upper core tube 5 by threads; the upper damping spring 7 is fitted on the upper core tube 5, and the upper and lower ends are connected to the upper core tube 5. The upper shock-absorbing ring 6 and the upper support sleeve 8 are connected by welding; the limiting sleeve 33 is connected to the upper central tube 1 by threads; the open retaining ring 16 is installed in the limiting groove of the locking block 15, and the locking block 15 is connected to the central tube 1 by limiting shear pins 18; the upper end of the upper support sleeve 8 is fitted inside the upper central tube 5, and the lower end is connected to the fixing sleeve 28 by threads; the unsealing C-shaped ring 31 is fitted on the unsealing connecting sleeve 29 and is also installed in the sliding groove of the upper support sleeve 8; the fixing sleeve 28 is fitted on the lower central tube 19 and connected by unsealing shear pins 32. The unsealing sleeve 30 is connected to the unsealing sleeve 30; the fixing C-ring 23 is fitted onto the lower core tube 19 and installed within the annular space formed by the fixing sleeve 28 and the unsealing sleeve 30; the locking plate on the unsealing connecting sleeve 29 is fitted onto the unsealing sleeve 30, and the unsealing connecting sleeve 29 is connected to the upper glue tube seat 37 by threads; the glue tube 22 is fitted onto the lower core tube 19, and its upper and lower ends abut against the upper glue tube seat 37 and the glue tube ring 38, respectively; the glue tube ring 38, the balance piston 39, and the lower glue tube seat 40 are fitted onto the lower core tube 19, and the lower glue tube seat 40 is connected by threads. The threaded connection is connected to the lower pressure cap 26; the C-shaped locking ring 27 is fitted onto the locking sleeve 25 and installed in the annular space of the lower pressure cap 26; the locking sleeve 25 is connected to the lower core tube 19 by threads; the lower connector 9 is connected to the lower core tube 19 by threads; the limiting ring 41 is installed in the annular space formed by the lower connector 9 and the lower core tube 19; the lower damping spring 11 is fitted onto the central tube 1, and its upper and lower ends are connected to the lower connector 9 and the lower damping ring 10 by welding; the lower damping ring 10 is connected to the central tube 1 by fixing shear pins 12.

[0077] The working process of the plunger staged gas lift clamp provided in this embodiment is as follows:

[0078] refer to Figures 1 to 12 The plunger is lowered to the construction position by a staged air lift device. At this time, the protrusion 13 on the upper support sleeve 8 is locked at the oil pipe coupling position. The release shear pin 4 is cut by the shock absorber. After the release shear pin 4 is cut, the central tube 1 loses its constraint and moves downward under the force of the lower shock absorber spring 11 returning to its original position. During the downward movement, the central tube 1 drives the locking block 15, the open retaining ring 16, and the limiting shear pin 18 to move together. When the open retaining ring 16 reaches the groove 14 on the upper support sleeve 8, the open retaining ring 16 returns to its original position and locks the locking block 15 together, realizing the mounting of the device.

[0079] As the central tube 1 continues to move downward, it cuts the limiting shear pin 18. At this time, the locking block 15 and the central tube 1 only make contact but do not move synchronously. During the downward movement of the central tube 1, the second protrusion 21 on the central tube 1 loses contact with the sealing ring 24. The accumulated liquid in the oil pipe is conducted through the pressure transmission hole 20 to the space enclosed by the lower rubber sleeve seat 40 and the locking sleeve 25. Under the pressure of the accumulated liquid column, the lower rubber sleeve seat 40 is pushed to squeeze the rubber sleeve ring 38 to achieve the setting of the rubber sleeve 22. During the upward movement of the lower rubber sleeve seat 40, the C-shaped locking ring 27 and the lower pressure cap 26 move upward together. During the upward movement, the C-shaped locking ring 27 locks into the locking sleeve 25 to prevent the rubber sleeve 22 from rebounding. This process completes the setting of the locking device.

[0080] After the locking device completes setting, the plunger can perform staged air lift operation. When the lower-stage plunger carries the accumulated liquid upward, the accumulated liquid can enter the central tube 1 through the flow hole 34 on the central tube 1, and then enter the upper-stage plunger space through the one-way valve 3. When the lower-stage plunger reaches the lower damping ring 10 of the locking device, it pushes the lower damping ring 10 and the central tube 1 upward. During the upward movement, the central tube 1 pushes the upper-stage plunger locked on the positioning ball 36, causing it to disengage from the upper damping ring 6, and the air lift operation begins.

[0081] When it is necessary to release the locking device, the retrieval tool is lowered into the central tube 1. After retrieving the central tube 1, it is lifted to cut the fixing pin 12. Then, the lifting continues until the groove 14 of the central tube 1 reaches the locking block 15. The locking block 15 is in an autonomous state, and the split spring structure on the upper support sleeve 8 also loses its support and is in a free state. At this time, the central tube 1 continues to be lifted, causing the upper central tube 5, the upper support sleeve 8, and the limiting sleeve 33 to move upward. The upper support sleeve 8 is in... During the upward movement, the fixing sleeve 28 is driven to move upward. During the upward movement, the fixing sleeve 28 cuts the unsealing clip 32. After the unsealing clip 32 is cut, the split claw structure at the front end of the unsealing sleeve 30 loses its support and is in a free state. At this time, the unsealing connecting sleeve 29 loses the obstruction of the upper stepped surface of the unsealing sleeve 30 and moves upward together with the upper glue tube seat 37, providing a rebound space for the glue tube 22. Under the action of elastic force, the glue tube 22 rebounds and returns to its original shape, completing the unsealing of the locking device.

[0082] This locking device can withstand the impact of both the lower and upper plungers. It is equipped with multiple sealing rings 24 to prevent the liquid carried by the lower plunger from slipping off the locking device. Simultaneously, the one-way valve 3 built into the central tube 1 works in conjunction with the sealing rings 24 to further prevent the liquid carried by the lower plunger from slipping off. The upper shock-absorbing ring 6 is equipped with a positioning spring 35 and a positioning ball 36. The upper plunger can only be activated when the lower plunger reaches the locking device position; that is, the lower plunger lifts all the liquid to the upper part of the locking device before the upper plunger can operate.

[0083] 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 or all of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A locking device for a plunger staged gas lift, characterized in that, include: Central tube (1) and discard (2); A flow valve (3) is provided inside the central tube (1); The drop head (2) is sleeved on one end of the central tube (1) and connected to the central tube (1) by the drop head scissor nail (4); From the other end of the drop handle (2) to the other end of the central tube (1), the central tube (1) is sequentially fitted with an upper shock-absorbing assembly, a seat-hanging assembly, a seat-sealing assembly and a lower shock-absorbing assembly; The upper shock absorption assembly includes an upper core tube (5), an upper shock absorption ring (6) and an upper shock absorption spring (7), and the seat hanger assembly includes an upper support sleeve (8); The upper tube (5) is sleeved on the central tube (1); The upper shock-absorbing ring (6) is sleeved on the central tube (1) and threadedly connected to the end of the upper central tube (5) near the drop head (2); The upper support sleeve (8) includes a limiting section, which is sleeved on the upper core tube (5) and can slide along the axial direction of the upper core tube (5) between the upper shock absorber ring (6) and the end of the upper core tube (5) away from the upper shock absorber ring (6); The upper damping spring (7) is sleeved on the upper core tube (5) and is located between the upper damping ring (6) and the upper support sleeve (8). One end of the spring is fixedly connected to the upper damping ring (6), and the other end is fixedly connected to the upper support sleeve (8). The seat assembly includes a lower connector (9), and the lower damping assembly includes a lower damping ring (10) and a lower damping spring (11). The lower shock-absorbing ring (10) is sleeved on the other end of the central tube (1) and connected to the central tube (1) by a fixing screw (12); The lower damping spring (11) is sleeved on the central tube (1) and abuts between the lower damping ring (10) and the lower connector (9), with one end fixedly connected to the lower damping ring (10) and the other end fixedly connected to the lower connector (9). The upper support sleeve (8) also includes a seat hanging section extending out of the upper core tube (5). The outer wall of the seat hanging section is provided with a protrusion (13), and the inner wall opposite to the protrusion (13) is provided with a groove (14). The seat assembly also includes a locking block (15) and an open retaining ring (16) disposed between the seat section and the central tube (1). The locking block (15) is fixed to the outer wall of the central tube (1) and is located between the groove (14) and the upper central tube (5). The locking block (15) is provided with a limiting groove on the surface opposite to the seat section. The open retaining ring (16) is sleeved on the locking block (15), embedded in the limiting groove, and abuts against the inner wall of the seat hanging section.

2. The plunger staged gas lift locking device according to claim 1, characterized in that, The outer wall of the central tube (1) is provided with a first protrusion (17), and the locking block (15) is connected to the first protrusion (17) by a limiting shear pin (18).

3. The plunger staged gas lift locking device according to claim 2, characterized in that, The seat assembly also includes a lower core tube (19). The lower core tube (19) is sleeved on the central tube (1) and forms a flow passage between them. The lower core tube (19) is provided with a pressure transmission hole (20) that penetrates its side wall. The outer wall of the central tube (1) is also provided with a second protrusion (21), which is directly opposite the pressure transmission hole (20) and is sealed to the inner wall of the lower central tube (19). Along the axial direction of the lower core tube (19), the lower core tube (19) is sequentially fitted with an unsealing component, a rubber tube (22) and a sliding component; The unsealing component is fixedly connected to the seat hanging section and is also snapped to the lower core tube (19) by a fixed C-shaped ring (23); The sliding component and the lower core tube (19) form an annular cavity, which is connected to the pressure transmission hole (20); The lower connector (9) is sleeved on the lower core tube (19) and threadedly connected to the lower core tube (19) to support the sliding assembly.

4. The plunger staged gas lift locking device according to claim 3, characterized in that, The inner wall of the lower core tube (19) is fitted with two sealing rings (24), which are located on both sides of the pressure transmission hole (20) and abut against the second boss (21).

5. The plunger staged gas lift locking device according to claim 3, characterized in that, A locking sleeve (25) is also fitted on the lower core tube (19). The locking sleeve (25) is threadedly connected to the lower core tube (19) and is located within the space formed by the lower connector (9), the lower core tube (19) and the sliding assembly. The sliding assembly includes a pressure cap (26) and a C-shaped locking ring (27); The pressure cap (26) is fitted onto the locking sleeve (25); The C-shaped locking ring (27) is disposed between the lower pressure cap (26) and the locking sleeve (25), and is embedded in the lower pressure cap (26), and is also connected to the locking sleeve (25) by a toothed buckle.

6. The plunger staged gas lift locking device according to claim 5, characterized in that, The unsealing assembly includes a fixing sleeve (28), an unsealing connecting sleeve (29), and an unsealing sleeve (30); The fixing sleeve (28) is located between the lower core tube (19) and the seat section, and is threadedly connected to the seat section; The inner wall of the seat section away from the groove (14) is provided with a sliding groove, which extends along the axial direction of the seat section; The unsealing connecting sleeve (29) is fitted onto the fixed sleeve (28), and an unsealing C-shaped ring (31) is embedded on its outer wall. The unsealing C-shaped ring (31) is located in the sliding groove and can slide along the extension direction of the sliding groove. The unsealing sleeve (30) is located within the space formed by the lower core tube (19), the fixing sleeve (28) and the unsealing connecting sleeve (29), and is connected to the lower core tube (19) through the fixing C-ring (23), and is also connected to the fixing sleeve (28) through the unsealing scissor (32).

7. The plunger staged gas lift locking device according to claim 6, characterized in that, The unsealing sleeve (30) includes an integrally formed connecting section and a split locking claw; The diameter of the connecting segment is smaller than the diameter of the segmented claw; The segmented claw forms a step with the connecting section and is connected to the fixing sleeve (28) by the unsealing screw (32). The inner wall of the unsealing connecting sleeve (29) protrudes to form a locking platform, which contacts the outer wall of the connecting segment and also contacts the stepped surface between the split locking claw and the connecting segment.

8. The plunger staged gas lift locking device according to claim 1, characterized in that, The upper shock absorber assembly also includes a limiting sleeve (33), which is sleeved on the upper core tube (5) and threadedly connected to the upper core tube (5); The limiting segment is connected between the limiting sleeve (33) and the upper shock-absorbing spring (7).

9. The plunger staged gas lift locking device according to claim 1, characterized in that, The central tube (1) is a barrel shape with one end open and the other end closed, and multiple flow holes (34) are provided on the side wall on which the lower shock absorber spring (11) is sleeved. The lower shock absorber ring (10) is inserted into the closed end of the central tube (1), and its sidewall is connected to the central tube (1) through the fixing screw (12).

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