Clamping device for plunger step-by-step gas lifting

Abstract

The invention relates to the technical field of oil and gas reservoir drainage and gas recovery, in particular to a clamping device for plunger step-by-step gas lift, and aims to solve the technical problem that an existing clamping device cannot be applied to step-by-step plunger gas lift. The clamping device for plunger step-by-step gas lifting can bear the impact of a lower-stage plunger and can also bear the impact of an upper-stage plunger; accumulated liquid carried by the lower-stage plunger is prevented from slipping off from the clamping device through the check valve arranged in the central pipe; in addition, when the lower-stage plunger reaches the position of the clamping device, the upper-stage plunger can be started, that is, the lower-stage plunger lifts all accumulated liquid to the upper portion of the clamping device, the upper-stage plunger can work, and normal production of a gas well is guaranteed.

Description

Technical Field

[0001] The invention relates to the technical field of oil and gas reservoir drainage and gas production, and in particular to a retainer for plunger step-by-step gas lifting. Background Art

[0002] The plunger gas lift drainage gas production process is one of the main processes for stable production of gas wells. However, with the continuous production of gas wells, the bottom hole pressure will gradually decrease and the liquid accumulation will become more serious. When a single-stage plunger is used, insufficient pressure in the well will cause the plunger to fail to reach the wellhead and fail to drain the liquid, resulting in process failure and the inability of the gas well to produce normally. Therefore, it is necessary to install multiple plunger retainers in the well for step-by-step plunger gas lift.

[0003] However, the retainer currently used for single-stage plunger gas lift can only withstand the unidirectional impact of the plunger, and does not consider the problem of fluid slippage. Therefore, it cannot be used in step-by-step plunger gas lift. Summary of the invention

[0004] The object of the present invention is to provide a retainer for step-by-step plunger gas lift to solve the technical problem that the existing retainer cannot be used in step-by-step plunger gas lift.

[0005] In order to solve the above technical problems, the technical solution provided by the present invention is:

[0006] The plunger step-by-step gas lift retainer provided by the present invention comprises: a center tube and a release head;

[0007] A check valve is provided in the central tube;

[0008] The release head is sleeved on one end of the central tube and connected to the central tube via release shear nails;

[0009] From the hand-dropping head to the other end of the central tube, the central tube is sequentially sleeved with an upper shock-absorbing assembly, a seating assembly, a seating assembly and a lower shock-absorbing assembly;

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

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

[0012] The upper damping ring is sleeved on the central tube and is threadedly connected to the end of the upper central tube close to the hand-dropping head;

[0013] The upper support sleeve comprises 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 an end of the upper core tube away from the upper damping ring;

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

[0015] The setting assembly includes a lower joint, and the lower shock absorbing assembly includes a lower shock absorbing ring and a lower shock absorbing spring;

[0016] The lower shock-absorbing ring is sleeved on the other end of the central tube and connected to the central tube via fixed shear nails;

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

[0018] Furthermore, the upper support sleeve also includes a hanging section extending out of the upper core tube, the outer wall of the hanging section is provided with a protrusion, and the inner wall directly facing the protrusion is provided with a groove;

[0019] The seating assembly further includes a locking block and an open snap ring disposed between the seating section and the center 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, and a limiting groove is provided on the surface of the locking block opposite to the hanging section;

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

[0022] Furthermore, a first boss is provided on the outer wall of the central tube, and the locking block is connected to the first boss via a limiting shear nail.

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

[0024] The lower core tube is sleeved on the central tube and forms a flow passage with the central tube, and the lower core tube is provided with a pressure transmission hole penetrating through its side wall;

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

[0026] Along the axial direction of the lower core tube, the lower core tube is sequentially sleeved with an unsealing component, a rubber cylinder and a sliding component;

[0027] The unsealing assembly is fixedly connected to the seating section and is also clamped to the lower core tube via a fixed C-shaped ring;

[0028] The sliding assembly and the lower core tube are arranged to form an annular cavity, and the annular cavity is communicated with the pressure transmission hole;

[0029] The lower joint is sleeved on the lower core pipe and is threadedly connected with the lower core pipe to support the sliding assembly.

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

[0031] Furthermore, a locking sleeve is sleeved on the lower core tube, the locking sleeve is threadedly connected to the lower core tube, and is located in a space surrounded by the lower joint, the lower core tube and the sliding assembly;

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

[0033] The pressing cap is sleeved on the locking sleeve;

[0034] The C-shaped locking ring is arranged between the pressing cap and the locking sleeve, embedded in the pressing cap, and connected to the locking sleeve through a tooth buckle.

[0035] Further, the unsealing assembly 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 seating section, and is threadedly connected to the seating section;

[0037] A sliding groove is provided on the inner wall of the sitting section away from the groove, and the sliding groove extends along the axial direction of the sitting section;

[0038] The unsealing connecting sleeve is sleeved on the fixing sleeve, and an unsealing C-shaped ring is embedded on the outer wall of the fixing sleeve. The unsealing C-shaped ring is located in the sliding groove and can slide along the extending direction of the sliding groove.

[0039] The unsealing sleeve is located in a space formed by the lower core tube, the fixed sleeve and the unsealing connecting sleeve, and is connected to the lower core tube through the fixed C-shaped ring, and is also connected to the fixed sleeve through unsealing shear nails.

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

[0041] The diameter of the connecting section is smaller than the diameter of the split claw;

[0042] A step is formed between the petal-splitting claw and the connecting section, and the petal-splitting claw is connected to the fixing sleeve through the unsealing shear pin;

[0043] The inner wall of the unsealing connection sleeve is protruded to form a clamping platform, which contacts the outer wall of the connecting section and also contacts the stepped surface between the petal clamping claw and the connecting section.

[0044] Furthermore, the upper shock-absorbing assembly further comprises a limiting sleeve, which is arranged on the upper core tube and is threadedly connected to the upper core tube;

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

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

[0047] The lower shock-absorbing ring is plug-fitted with the closed end of the central tube, and its side wall is connected to the central tube through the fixed shear nails.

[0048] In summary of the above technical solutions, the technical effects that can be achieved by the plunger step-by-step gas lift retainer provided by the present invention are:

[0049] In the retainer for the plunger step-by-step gas lift, the upper shock-absorbing ring is used to connect with the upper plunger. When subjected to the pressure exerted by the upper plunger, the upper shock-absorbing ring will compress the upper shock-absorbing spring. When the lower plunger moves upward with the accumulated fluid, the accumulated fluid will enter the center tube, and the presence of the one-way valve prevents the accumulated fluid from falling back. When the lower plunger reaches the lower shock-absorbing ring, it will push the lower shock-absorbing ring and the center tube to move, thereby compressing the lower shock-absorbing spring. At the same time, the center tube will push the upper plunger connected to the upper shock-absorbing ring during the movement, so that the upper plunger is separated from the upper shock-absorbing ring and the gas lift operation begins.

[0050] It can be seen that compared with the prior art, the retainer for the plunger step-by-step gas lift can withstand the impact of both the lower plunger and the upper plunger; the one-way valve arranged in the central tube prevents the accumulated liquid carried by the lower plunger from slipping off the retainer; in addition, the upper plunger can only be started when the lower plunger reaches the retainer position, that is, the lower plunger lifts all the accumulated liquid to the upper part of the retainer before the upper plunger can work, thereby ensuring the normal production of the gas well. BRIEF DESCRIPTION OF THE DRAWINGS

[0051] In order to more clearly illustrate the specific implementation methods of the present invention or the technical solutions in the prior art, the drawings required for use in the specific implementation methods or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are some implementation methods of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0052] Figure 1A cross-sectional view of a plunger step-by-step gas lift retainer provided in an embodiment of the present invention;

[0053] Figures 2 to 4 for Figure 1 Cross-sectional views of different sections from top to bottom;

[0054] Figure 5 A cross-sectional view of a plunger after being set by a locking device for step-by-step gas lift provided by an embodiment of the present invention;

[0055] Figures 6 to 8 for Figure 5 Cross-sectional views of different sections from top to bottom;

[0056] Fig. 9 A cross-sectional view of a plunger after the locking device for step-by-step gas lift provided by an embodiment of the present invention is unsealed;

[0057] Figures 10 to 12 for Fig. 9 Cross-sectional views of different sections from top to bottom.

[0058] Icons: 1-center tube; 2-handle head; 3-check valve; 4-handle shear pin; 5-upper center tube; 6-upper damping ring; 7-upper damping spring; 8-upper support sleeve; 9-lower joint; 10-lower damping ring; 11-lower damping spring; 12-fixed shear pin; 13-bump; 14-groove; 15-locking block; 16-opening clamp; 17-first boss; 18-limited shear pin; 19-lower center tube; 20-pressure transmission hole; 21-second boss ; 22-rubber cylinder; 23-fixed C-shaped ring; 24-sealing ring; 25-locking sleeve; 26-pressing cap; 27-C-shaped locking ring; 28-fixing sleeve; 29-unsealing connecting sleeve; 30-unsealing sleeve; 31-unsealing C-shaped ring; 32-unsealing shear pin; 33-limiting sleeve; 34-flow hole; 35-positioning spring; 36-positioning ball; 37-upper rubber cylinder seat; 38-rubber cylinder ring; 39-balancing piston; 40-lower rubber cylinder seat; 41-limiting ring. DETAILED DESCRIPTION

[0059] In order to make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Generally, the components of the embodiments of the present invention described and shown in the drawings here can be arranged and designed in various different configurations.

[0060] Therefore, the following detailed description of the embodiments of the present invention provided in the accompanying drawings is not intended to limit the scope of the invention claimed for protection, but merely represents selected embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0061] Some embodiments of the present invention are described in detail below in conjunction with the accompanying drawings. In the absence of conflict, the following embodiments and features in the embodiments can be combined with each other.

[0062] The retainer currently used for single-stage plunger gas lift can only withstand the unidirectional impact of the plunger, and does not consider the problem of fluid slippage. Therefore, it cannot be used in step-by-step plunger gas lift.

[0063] In view of this, the present invention provides a plunger step-by-step gas lift retainer, comprising a center tube 1 and a release head 2; a check valve 3 is arranged in the center tube 1; the release head 2 is sleeved on one end of the center tube 1 and is connected to the center tube 1 through a release shear nail 4; from the release head 2 to the other end of the center tube 1, the center tube 1 is sequentially sleeved with an upper shock-absorbing assembly, a seating assembly, a sealing assembly and a lower shock-absorbing assembly; the upper shock-absorbing assembly comprises an upper core tube 5, an upper shock-absorbing ring 6 and an upper shock-absorbing spring 7, and the seating assembly comprises an upper support sleeve 8; the upper core tube 5 is sleeved on the center tube 1; the upper shock-absorbing ring 6 is sleeved on the center tube 1 and is threadedly connected to the end of the upper core tube 5 close to the release head 2; the upper support sleeve 8 comprises a limiting section, and the limiting section is sleeved on the upper The upper core tube 5 can slide along the axial direction of the upper core tube 5 between the upper shock-absorbing ring 6 and the end of the upper core tube 5 away from the upper shock-absorbing ring 6; the upper shock-absorbing spring 7 is sleeved on the upper core tube 5 and is located between the upper shock-absorbing ring 6 and the upper support sleeve 8, and one end of it is fixedly connected to the upper shock-absorbing ring 6, and the other end is fixedly connected to the upper support sleeve 8; the sealing assembly includes a lower joint 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 center tube 1 and is connected to the center tube 1 by a fixed shear nail 12; the lower shock-absorbing spring 11 is sleeved on the center tube 1 and abuts between the lower shock-absorbing ring 10 and the lower joint 9, and one end of it is fixedly connected to the lower shock-absorbing ring 10, and the other end is fixedly connected to the lower joint 9.

[0064] In the piston step-by-step gas lift retainer, the upper damping ring 6 is used to connect with the upper plunger. When subjected to the pressure applied by the upper plunger, the upper damping ring 6 will compress the upper damping spring 7. When the lower plunger moves upward with the accumulated fluid, the accumulated fluid will enter the central tube 1, and the presence of the check valve 3 prevents the accumulated fluid 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, the central tube 1 will push the upper plunger connected to the upper damping ring 6 during the movement, so that the upper plunger is separated from the upper damping ring 6 and the gas lift operation begins.

[0065] It can be seen that, compared with the prior art, the retainer for the plunger step-by-step gas lift can withstand the impact of both the lower plunger and the upper plunger; the one-way valve 3 arranged in the central pipe 1 prevents the accumulated liquid carried by the lower plunger from slipping off the retainer; in addition, the upper plunger can only be started when the lower plunger reaches the retainer position, that is, the lower plunger lifts all the accumulated liquid to the upper part of the retainer before the upper plunger can work, thereby ensuring the normal production of the gas well.

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

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

[0068] Specifically, Figure 2 For example, when in use, the plunger is gas lifted step by step to the construction position with a retainer. At this time, the protrusion 13 on the upper support sleeve 8 is fixed at the position of the oil pipe coupling, and the release shear nail 4 is sheared off by the jar. After the release shear nail 4 is sheared off, the center pipe 1 loses its constraint and moves downward under the driving force of the lower shock-absorbing spring 11 to restore the original position; during the downward movement of the center pipe 1, the retaining lock block 15, the open retaining ring 16, and the limit shear nail 18 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 the retaining lock block 15 is locked together, so that the retainer is hung, such as Figure 5 and Figure 6 shown.

[0069] For 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 passage with the central tube 1, and a pressure transmission hole 20 penetrating the side wall thereof is provided on the lower core tube 19; a second boss 21 is also provided on the outer wall of the central tube 1, and the second boss 21 is directly opposite to the pressure transmission hole 20 and is sealed with the inner wall of the lower core tube 19; along the axial direction of the lower core tube 19, an unsealing component, a rubber cylinder 22 and a sliding component are sequentially sleeved on the lower core tube 19; the unsealing component is fixedly connected to the seating section, and is also clamped with the lower core tube 19 through a fixed C-shaped ring 23; the sliding component and the lower core tube 19 are surrounded to form an annular cavity, and the annular cavity is communicated with the pressure transmission hole 20; the lower joint 9 is sleeved on the lower core tube 19 and is threadedly connected to the lower core tube 19 to support the sliding component.

[0070] Specifically, refer to Figures 2 to 4 The outer wall of the central tube 1 is provided with a first boss 17, and the locking block 15 is connected to the first boss 17 through a limiting shear nail 18. Two sealing rings 24 are embedded in the inner wall of the lower core tube 19, and the two sealing rings 24 are located on both sides of the pressure transmission hole 20 and are both in contact with the second boss 21. Figures 5 to 7 After the retainer is seated, the center tube 1 continues to move downward to cut off the limit shear nail 18. At this time, the locking block 15 and the first boss 17 only abut against each other and move asynchronously. During the downward movement of the center tube 1, the second boss 21 loses contact with the sealing ring 24, and the accumulated 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-transmitting hole 20. Under the pressure of the accumulated liquid column, the sliding assembly will slide upward to squeeze the rubber cylinder 22 to complete the sealing of the retainer.

[0071] For further reference, Figure 3 The lower core tube 19 is also provided with a locking sleeve 25, which is threadedly connected to the lower core tube 19 and is located in a space surrounded by the lower joint 9, the lower core tube 19 and the sliding assembly; the sliding assembly includes a pressing cap 26 and a C-shaped locking ring 27; the pressing cap 26 is sleeved on the locking sleeve 25; the C-shaped locking ring 27 is arranged between the pressing cap 26 and the locking sleeve 25, and is embedded in the pressing cap 26, and is also connected to the locking sleeve 25 through a horse tooth buckle.

[0072] Specifically, when the sliding assembly slides upward, the pressing cap 26 and the C-shaped locking ring 27 move upward, and the C-shaped locking ring 27 is locked to the locking sleeve 25 during the upward movement, thereby preventing the rubber cylinder 22 from rebounding and ensuring the effectiveness of the rubber cylinder 22 sealing.

[0073] For further information, please refer to Figure 3The unsealing component 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 hanging section, and is threadedly connected to the hanging section; a sliding groove is provided on the inner wall of the hanging section away from the groove 14, and the sliding groove extends along the axial direction of the hanging 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, and the unsealing C-shaped ring 31 is in the sliding groove and can slide along the extension direction of the sliding groove; the unsealing sleeve 30 is 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 is also connected to the fixed sleeve 28 through the unsealing shear nail 32.

[0074] Please continue to refer to Figure 3 The unsealing sleeve 30 includes an integrally formed connecting section and a petal claw; the diameter of the connecting section is smaller than the diameter of the petal claw; a step is formed between the petal claw and the connecting section, and is connected to the fixed sleeve 28 through an unsealing shear nail 32; the inner wall of the unsealing connecting sleeve 29 protrudes to form a clamping platform, which contacts the outer wall of the connecting section and also contacts the step surface between the petal claw and the connecting section.

[0075] refer to Figures 5 to 8 During the setting process of the retainer, the fixed sleeve 28, the unsealing connecting sleeve 29 and the unsealing sleeve 30 are fixed to the upper support sleeve 8, and cooperate with the sliding assembly to squeeze the rubber cylinder 22. When the retainer needs to be unsealed, the fishing tool is lowered into the center, the center pipe 1 is caught and lifted up to cut off the fixed shear nail 12, and then the lifting is continued; refer to Figures 9 to 12 When the first boss 17 is separated from the locking block 15, the locking block 15 will be in an autonomous state. At this time, the upper petal-type spring sheet structure of the upper support sleeve 8 loses support and is also in a free state. At this time, the center tube 1 continues to be lifted, which will drive the upper core 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 in the sliding groove relative to the upper support sleeve 8, that is, the unsealing connecting sleeve 29 does not move, and the fixed sleeve 28 moves upward synchronously, and the fixed sleeve 28 cuts the unsealing shear nail 32 during the upward movement; after the unsealing shear nail 32 is cut off, the petal claws at the front end of the unsealing sleeve 30 lose support and are in a free state. At this time, the unsealing connecting sleeve 29 loses the obstruction of the upper step surface of the unsealing sleeve 30, and moves upward under the drive of the upper support sleeve 8. In this way, the rubber cylinder 22 loses its limit, and rebounds under the action of its own elastic force to restore the original state, thereby completing the unsealing of the retainer.

[0076] refer to Figures 1 to 4In the plunger step-by-step gas lift retainer provided in the embodiment of the present application, the release head 2 is fixed to the central tube 1 by the release shear nail 4. At the same time, the release head 2, the central tube 1 and the fixed shear nail 12 work together to limit the upper shock-absorbing ring 6 and the lower shock-absorbing ring 10, so that the lower shock-absorbing spring 11 of the retainer is in a compressed state in the initial state; the positioning spring 35 and the positioning ball 36 are installed in the upper shock-absorbing ring 6, and the upper shock-absorbing ring 6 is connected to the upper central tube 5 by a thread; the upper shock-absorbing spring 7 is sleeved on the upper central tube 5, and the upper and lower ends are connected The upper damping ring 6 and the upper support sleeve 8 are connected by welding; the limiting sleeve 33 is connected to the upper center tube 1 by threads; the open snap ring 16 is installed in the limiting groove of the locking block 15, and the locking block 15 is connected to the center tube 1 by limiting shear nails 18; the upper end of the upper support sleeve 8 is sleeved in the upper core tube 5, and the lower end is connected to the fixing sleeve 28 by threads; the unsealing C-shaped ring 31 is sleeved on the unsealing connecting sleeve 29 and installed in the sliding groove of the upper support sleeve 8; the fixing sleeve 28 is sleeved on the lower core tube 19, and is connected to the upper center tube 19 by unsealing shear nails 32 The fixed C-shaped ring 23 is sleeved on the lower core tube 19 and installed in the annular space surrounded by the fixed sleeve 28 and the unsealing sleeve 30; the card table on the unsealing connecting sleeve 29 is mounted on the unsealing sleeve 30, and the unsealing connecting sleeve 29 is connected to the upper rubber cylinder seat 37 through a thread; the rubber cylinder 22 is sleeved on the lower core tube 19, and the upper and lower ends are respectively abutted against the upper rubber cylinder seat 37 and the rubber cylinder ring 38; the rubber cylinder ring 38, the balance piston 39 and the lower rubber cylinder seat 40 are sleeved on the lower core tube 19, and the lower rubber cylinder seat 40 is screwed The thread is connected to the lower pressure cap 26; the C-shaped locking ring 27 is sleeved on 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 a thread; the lower joint 9 is connected to the lower core tube 19 by a thread; the limit ring 41 is installed in the annular space formed by the lower joint 9 and the lower core tube 19; the lower shock-absorbing spring 11 is sleeved on the center tube 1, and the upper and lower ends are connected to the lower joint 9 and the lower shock-absorbing ring 10 by welding; the lower shock-absorbing ring 10 is connected to the center tube 1 by fixing shear nails 12.

[0077] The working process of the plunger step-by-step gas lift retainer provided in this embodiment is as follows:

[0078] refer to Figures 1 to 12 , the plunger is gas lifted step by step to the construction position with a retainer. At this time, the protrusion 13 on the upper support sleeve 8 is fixed at the position of the oil pipe coupling, and the shear nail 4 is cut off by the jar. After the shear nail 4 is cut off, the center pipe 1 loses its constraint and moves downward under the driving force of the lower shock-absorbing spring 11 to restore the original position. During the downward movement, the center pipe 1 drives the locking block 15, the open snap ring 16, and the limiting shear nail 18 to move together. When the open snap ring 16 reaches the groove 14 on the upper support sleeve 8, the open snap ring 16 returns to its original position and locks the locking block 15 together to realize the hanging of the retainer.

[0079] The center tube 1 continues to move downward to cut off the limiting shear pin 18. At this time, the locking block 15 and the center tube 1 only achieve abutment and asynchronous movement. During the downward movement of the center tube 1, the second boss 21 on the center tube 1 loses contact with the sealing ring 24, and the accumulated liquid in the oil pipe is transmitted to the space enclosed by the lower rubber cylinder seat 40 and the locking sleeve 25 through the pressure transmission hole 20. Under the action of the pressure of the accumulated liquid column, the lower rubber cylinder seat 40 is pushed to squeeze the rubber cylinder ring 38 to achieve the sealing of the rubber cylinder 22. During the upward movement of the lower rubber cylinder seat 40, the C-shaped locking ring 27 and the lower pressure cap 26 are driven to move upward together. The C-shaped locking ring 27 is locked to the locking sleeve 25 during the upward movement to prevent the rubber cylinder 22 from rebounding. This process completes the sealing of the retainer.

[0080] After the locking device is sealed, the plunger can perform gas lift construction step by step. When the lower-level plunger moves upward with the accumulated liquid, the accumulated liquid can enter the center tube 1 through the flow hole 34 on the center tube 1, and then enter the upper-level plunger space through the check valve 3. When the lower-level plunger reaches the lower shock-absorbing ring 10 of the locking device, it pushes the lower shock-absorbing ring 10 and the center tube 1 to move upward. During the upward movement, the center tube 1 pushes the upper-level plunger fixed on the positioning ball 36 to disengage it from the upper shock-absorbing ring 6, and start gas lift work.

[0081] When it is necessary to unseal the retainer, the fishing tool is lowered into the central tube 1, and the central tube 1 is lifted up after being fished out to cut off the fixing shear nail 12, and then the lifting is continued. When the groove 14 of the central tube 1 reaches the locking block 15, the locking block 15 is in an autonomous state, and the petal-type spring sheet structure on the upper support sleeve 8 also loses support and is in a free state. At this time, the central tube 1 continues to be lifted up, driving the upper central tube 5, the upper support sleeve 8, and the limit sleeve 33 to move upward, and the upper support sleeve 8 is in a During the upward movement, the fixing sleeve 28 is driven to move upward, and the fixing sleeve 28 cuts the unsealing shear pins 32 during the upward movement. After the unsealing shear pins 32 are cut, the petal 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 step surface of the unsealing sleeve 30, and moves upward together with the upper glue cylinder seat 37, providing a rebound space for the glue cylinder 22. Under the action of elastic force, the glue cylinder 22 rebounds and returns to its original state, completing the unsealing of the retainer.

[0082] The use of this retainer can withstand the impact of both the lower plunger and the upper plunger, and the retainer is provided with multiple sealing rings 24 to prevent the accumulated liquid carried by the lower plunger from slipping off the retainer. At the same time, the built-in check valve 3 in the central tube 1 works together with the sealing ring 24 to further prevent the accumulated liquid carried by the lower plunger from slipping off; the upper damping ring 6 is provided with a positioning spring 35 and a positioning ball 36, and the upper plunger can only be started when the lower plunger reaches the retainer position, that is, the lower plunger lifts all the accumulated liquid to the upper part of the retainer before the upper plunger can work.

[0083] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or replace some or all of the technical features therein by equivalents. However, these modifications or replacements 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 plunger step-by-step gas lift retainer, characterized in that: include: A central tube (1) and a dropper (2); A check valve (3) is provided in the central tube (1); The release head (2) is sleeved on one end of the central tube (1) and is connected to the central tube (1) via a release shear nail (4); From the hand-dropping head (2) to the other end of the central tube (1), an upper shock-absorbing assembly, a seating assembly, a sealing assembly and a lower shock-absorbing assembly are sequentially sleeved on the central tube (1); The upper shock-absorbing assembly comprises an upper core tube (5), an upper shock-absorbing ring (6) and an upper shock-absorbing spring (7), and the seat-hanging assembly comprises an upper support sleeve (8); The upper core tube (5) is sleeved on the central tube (1); The upper damping ring (6) is sleeved on the central tube (1) and is threadedly connected to the end of the upper central tube (5) close to the hand-dropping head (2); The upper support sleeve (8) comprises 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 damping ring (6) and an end of the upper core tube (5) away from the upper damping 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), and one end of the upper damping spring is fixedly connected to the upper damping ring (6) and the other end is fixedly connected to the upper support sleeve (8); The setting assembly comprises a lower joint (9), and the lower shock absorbing assembly comprises 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) via fixed shear nails (12); The lower shock absorbing spring (11) is sleeved on the central tube (1) and abuts between the lower shock absorbing ring (10) and the lower joint (9), and one end of the lower shock absorbing spring (11) is fixedly connected to the lower shock absorbing ring (10) and the other end is fixedly connected to the lower joint (9).

2. The plunger step-by-step gas lift retainer according to claim 1, characterized in that: The upper support sleeve (8) further comprises a hanging section extending out of the upper core tube (5), the outer wall of the hanging section being provided with a protrusion (13), and the inner wall directly facing the protrusion (13) being provided with a groove (14); The seating assembly further comprises a locking block (15) and an open snap ring (16) arranged between the seating 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), and a limiting groove is provided on the surface of the locking block (15) opposite to the hanging section; The open clamping ring (16) is sleeved on the locking block (15), embedded in the limiting groove, and abuts against the inner wall of the hanging section.

3. The plunger step-by-step gas lift retainer according to claim 2, characterized in that: The outer wall of the central tube (1) is provided with a first boss (17), and the locking block (15) is connected to the first boss (17) via a limiting shear nail (18).

4. The plunger step-by-step gas lift retainer according to claim 3, characterized in that: The setting 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 with the central tube (1), and the lower core tube (19) is provided with a pressure transmission hole (20) penetrating through the side wall thereof; The outer wall of the central tube (1) is also provided with a second boss (21), the second boss (21) is directly opposite to the pressure transmission hole (20) and is sealed with the inner wall of the lower core tube (19); Along the axial direction of the lower core tube (19), the lower core tube (19) is sequentially sleeved with an unsealing component, a rubber cylinder (22) and a sliding component; The unsealing assembly is fixedly connected to the seating section and is also clamped to the lower core tube (19) via a fixed C-shaped ring (23); The sliding assembly and the lower core tube (19) are arranged to form an annular cavity, and the annular cavity is communicated with the pressure transmission hole (20); The lower joint (9) is sleeved on the lower core tube (19) and is threadedly connected to the lower core tube (19) to support the sliding assembly.

5. The plunger step-by-step gas lift retainer according to claim 4, characterized in that: Two sealing rings (24) are embedded in the inner wall of the lower core tube (19). The two sealing rings (24) are located on both sides of the pressure transmission hole (20) and are both in contact with the second boss (21).

6. The plunger step-by-step gas lift retainer according to claim 4, characterized in that: The lower core tube (19) is also sleeved with a locking sleeve (25), the locking sleeve (25) is threadedly connected to the lower core tube (19) and is located in a space surrounded by the lower joint (9), the lower core tube (19) and the sliding assembly; The sliding assembly comprises a pressing cap (26) and a C-shaped locking ring (27); The pressing cap (26) is sleeved on the locking sleeve (25); The C-shaped locking ring (27) is arranged between the pressing cap (26) and the locking sleeve (25), and is embedded in the pressing cap (26), and is also connected to the locking sleeve (25) through a tooth buckle.

7. The plunger step-by-step gas lift retainer according to claim 6, characterized in that: The unsealing assembly comprises 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 seating section, and is threadedly connected to the seating section; A sliding groove is provided on the inner wall of the sitting section away from the groove (14), and the sliding groove extends along the axial direction of the sitting section; The unsealing connection sleeve (29) is sleeved on the fixed sleeve (28), and an unsealing C-shaped ring (31) is embedded on the outer wall of the unsealing connection sleeve. 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 a 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) via the fixed C-shaped ring (23), and is also connected to the fixed sleeve (28) via an unsealing shear nail (32).

8. The plunger step-by-step gas lift retainer according to claim 7, characterized in that: The unsealing sleeve (30) comprises an integrally formed connecting section and split claws; 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 the split claw is connected to the fixing sleeve (28) via the unsealing shear pin (32); The inner wall of the unsealing connection sleeve (29) is protruded to form a clamping platform, which contacts the outer wall of the connecting section and also contacts the stepped surface between the petal clamping claw and the connecting section.

9. The plunger step-by-step gas lift retainer according to claim 1, characterized in that: The upper shock-absorbing assembly further comprises a limiting sleeve (33), wherein the limiting sleeve (33) is sleeved on the upper core tube (5) and is threadedly connected to the upper core tube (5); The limiting section is connected between the limiting sleeve (33) and the upper damping spring (7).

10. The plunger step-by-step gas lift retainer according to claim 1, characterized in that: The central tube (1) is in the shape of a barrel with one end open and the other end closed, and a plurality of flow holes (34) are provided on the side wall on which the lower shock absorbing spring (11) is sleeved; The lower shock-absorbing ring (10) is plug-fitted to the closed end of the central tube (1), and its side wall is connected to the central tube (1) via the fixed shear nails (12).

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