Underground seating device for multi-stage plunger

Abstract

The invention relates to the technical field of oil and gas production of unconventional oil and gas reservoirs such as petroleum and natural gas, in particular to an underground seating device for a multi-stage plunger. According to the underground setting device for the multi-stage plunger, when a locking steel wire makes contact with an oil pipe coupling and bounces off, a right-angle step extends into the oil pipe coupling and is connected to the oil pipe coupling in a clamped mode, and first anchoring is formed; when the center rod moves in the direction close to the locking steel wire, the leather cup moves along the conical surface of the cone to abut against the inner wall of the oil pipe, and first sealing is formed. When the center rod moves in the direction close to the locking steel wire, the end, away from the slip connecting body, of the liquid discharging short section can abut against the rubber barrel, the rubber barrel abuts against the inner wall of the oil pipe under the action of pressure, and second sealing is formed; and when the slips expand in the direction away from the axis of the slips along the conical inclined surfaces until the slips are engaged with the inner wall of the oil pipe, second anchoring is formed. The multistage plunger seating device is provided with double anchoring mechanisms and double sealing mechanisms, and is large in anchoring force, good in sealing effect and stable in performance.

Description

Technical Field

[0001] The invention relates to the technical field of oil and gas production in unconventional oil and gas reservoirs such as petroleum and natural gas, and in particular to a downhole seat for a multi-stage plunger. Background Art

[0002] The multi-stage plunger drainage gas production process has the advantages of significantly reducing the plunger's starting pressure and improving the plunger's drainage efficiency, and has broad application prospects. The downhole seat supporting the multi-stage plunger drainage gas production process needs to withstand the bidirectional impact of its upper and lower plungers. The center flow channel of the seat is equipped with a single-flow valve and seals the annular space between it and the oil pipe to achieve the purpose of preventing the accumulated liquid from falling back. The seat used in the conventional plunger gas lift process is easy to get unstuck and move upward under the condition of being subjected to the bidirectional impact of the upper and lower plungers, resulting in the failure of the process operation. Summary of the invention

[0003] The purpose of the present invention is to provide a downhole seat for a multi-stage plunger to solve the problem that the seat used in the current conventional plunger gas lift process is easily unstuck and moved upward under the condition of the seat being subjected to the bidirectional impact of the upper and lower plungers, resulting in the failure of the process operation.

[0004] In order to solve the above technical problems, the technical solution provided by the present invention is:

[0005] A downhole seat for a multi-stage plunger, comprising: a cone, a slip, a slip connector, a liquid discharge nipple, a steel ball, a center rod, a rubber cylinder, a cone, a leather cup, an inner washer, an outer ring, an elastic claw and a locking steel wire;

[0006] The slips, the slip connector, the drainage nipple and the center rod are connected in sequence;

[0007] The conical body is inserted into the slip and the slip connector and extends into the drainage nipple. The conical body is slidably connected with the drainage nipple. A conical slide is provided at one end of the conical body away from the drainage nipple, and the slip can move along the conical slide.

[0008] One end of the center rod is inserted into the liquid discharge nipple, and the steel ball abuts against the port of the center rod close to the liquid discharge nipple, so that the liquid in the flow channel of the center rod can flow upwards but cannot fall back from the center rod;

[0009] The rubber cylinder, the cone, the leather cup, the inner gasket and the outer ring are sequentially sleeved on the outside of the central rod in a direction away from the liquid discharge nipple and can slide relative to the central rod. The outer ring is threadedly connected with the elastic claw. One end of the central rod away from the steel ball extends into the elastic claw and can slide relative to the elastic claw.

[0010] The elastic claw is provided with a right-angle step for clamping with the tubing coupling. The elastic claw is locked by the locking steel wire so that the right-angle step is not clamped with the tubing coupling. When the locking steel wire contacts the tubing coupling and pops open, the elastic claw unlocks the elastic claw, and the right-angle step extends into the tubing coupling and clamps with the tubing coupling, thereby forming a first anchoring.

[0011] When the center rod moves toward the direction close to the locking wire, the leather cup can move along the conical surface of the cone to abut against the inner wall of the oil pipe, thereby forming a first seal;

[0012] When the center rod moves toward the locking wire, the end of the drainage nipple away from the slip connector can abut against the rubber sleeve, and the rubber sleeve abuts against the inner wall of the oil pipe under the action of pressure, thereby forming a second seal;

[0013] When the slip expands along the conical slope in a direction away from the slip axis until the slip engages with the inner wall of the oil pipe, a second anchoring is formed.

[0014] Furthermore, the downhole seat for the multi-stage plunger further comprises an upper fishing head, an upper support rod, an upper damping spring and an upper support seat;

[0015] The upper fishing head is threadedly connected to the upper support rod, and the upper support rod extends into the upper support seat and can move relative to the upper support seat;

[0016] The upper damping spring is sleeved on the outside of the upper support rod, one end of the upper damping spring is connected to the upper fishing head, and the other end is connected to the upper support seat;

[0017] The upper support seat is connected to the cone body.

[0018] Furthermore, the downhole seat for the multi-stage plunger also includes a lower support seat, a lower damping spring, a lower support rod and a lower fishing head;

[0019] The lower fishing head is threadedly connected to the lower support rod, and the lower support rod extends into the lower support seat and can move relative to the lower support seat;

[0020] The lower shock absorbing spring is sleeved on the outside of the lower support rod, one end of the lower shock absorbing spring is connected to the lower salvaging head, and the other end is connected to the lower support seat;

[0021] The lower end of the elastic claw is connected to the lower support seat through a thread.

[0022] Furthermore, the slip connector is provided with a through hole, and the slip is connected to the slip connector via the through hole.

[0023] Furthermore, the conical body is provided with an upper limit block, a slide groove is provided in the liquid discharge short section, and the limit block is slidably connected to the slide groove.

[0024] Furthermore, the downhole seat for the multi-stage plunger further includes an elastic outer clamp;

[0025] The elastic outer clamp is sleeved on the outside of the slip.

[0026] Furthermore, the drainage nipple is provided with a drainage hole for drainage.

[0027] Furthermore, the downhole seat for the multi-stage plunger further includes a retaining spring;

[0028] The inner washer is threadedly connected to the outer ring and is surrounded by a clamping groove, and the outer ring of the clamping spring extends into the clamping groove.

[0029] Furthermore, the center rod is provided with an upper groove and a lower groove for cooperating with the inner ring of the retaining ring.

[0030] Furthermore, the central rod is provided with a lower step block, and the elastic claw is provided with a chamfer for abutting against the lower step block.

[0031] Based on the above technical solutions, the technical effects that can be achieved by the present invention are:

[0032] When the locking wire contacts the tubing coupling and pops open, the elastic claw unlocks the elastic claw, the right-angle step extends into the tubing coupling, and is clamped on the tubing coupling, forming the first anchoring; when the center rod moves toward the locking wire, the leather cup can move along the conical surface of the cone to abut against the inner wall of the tubing, forming the first seal; when the center rod moves toward the locking wire, the end of the drainage nipple away from the cava connector can abut against the rubber sleeve, and the rubber sleeve abuts against the inner wall of the tubing under pressure, forming the second seal; when the cava expands along the conical slope in the direction away from the cava axis until the cava bites with the inner wall of the tubing, forming the second anchoring. The multi-stage plunger seater of the present invention has a double anchoring mechanism and a double sealing mechanism, has a large anchoring force, a good sealing effect and a stable performance, and solves the problem that the seater used in the current conventional plunger gas lift process is easily unstuck and moved upward under the condition of the seater being subjected to the bidirectional impact of the upper and lower plungers, resulting in the failure of the process operation. BRIEF DESCRIPTION OF THE DRAWINGS

[0001] 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.

[0002] Figure 1 A schematic diagram of the structure of a downhole seat for a multi-stage plunger provided in an embodiment of the present invention;

[0003] Figure 2 for Figure 1 A magnified schematic diagram of position A in the middle;

[0004] Figure 3 for Figure 1 A magnified schematic diagram of position B in the middle;

[0005] Figure 4 for Figure 1 A magnified schematic diagram of the middle C position;

[0006] Figure 5 for Figure 1 A magnified schematic diagram of the D position in the middle;

[0007] Figure 6 for Figure 1 A magnified schematic diagram of the E position in the middle;

[0008] Figure 7 It is a schematic diagram of the structure of the slip connector;

[0009] Figure 8 It is a structural schematic diagram of the slip connector from another angle;

[0010] Fig. 9 It is a schematic diagram of the structure of a cone;

[0011] Fig.10 It is a structural schematic diagram of the drainage nipple;

[0012] Fig.11 is a schematic diagram of the structure of the center rod;

[0013] Fig.12 A schematic diagram of the setting state of the seater provided in an embodiment of the present invention;

[0014] Fig.13 for Fig.12 A magnified schematic diagram of the F position in the middle;

[0015] Fig.14 for Fig.12 A magnified schematic diagram of the G position in the middle;

[0016] Fig.15 for Fig.12 A magnified schematic diagram of the H position in the middle;

[0017] Fig.16 for Fig.12 A magnified schematic diagram of the middle I position;

[0018] Fig.17 for Fig.12 A magnified schematic diagram of the J position in the middle;

[0019] Fig.18 for Fig.12 A magnified schematic diagram of the middle K position;

[0020] Fig.19 It is a schematic diagram of the structure of the locking wire.

[0021] Icons: 1-upper fishing head; 2-upper support rod; 3-upper shock-absorbing spring; 4-upper support seat; 5-conical body; 51-upper limit block; 52-conical slideway; 6-slip; 7-elastic outer clamp; 8-slip connector; 81-through hole; 9-drainage short section; 91-slideway; 92-drainage hole; 10-steel ball; 11-center rod; 111-upper groove; 112-lower groove; 113-lower step block; 12-rubber cylinder; 13-conical body; 14-leather cup; 15-inner washer; 16-circlip; 17-outer ring; 171-slot; 18-elastic claw; 181-right-angle step; 182-chamfer; 19-locking wire; 20-lower support seat; 21-lower shock-absorbing spring; 22-lower support rod; 23-lower fishing head. DETAILED DESCRIPTION

[0022] 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.

[0023] 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.

[0024] 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.

[0025] The present invention provides a downhole seat for a multi-stage plunger, comprising: a cone 5, a slip 6, a slip connector 8, a liquid discharge short section 9, a steel ball 10, a center rod 11, a rubber cylinder 12, a cone 13, a leather cup 14, an inner washer 15, an outer ring 17, an elastic claw 18 and a locking wire 19; the slip 6, the slip connector 8, the liquid discharge short section 9 and the center rod 11 are connected in sequence; the cone 5 is inserted into the slip 6 and the slip connector 8, and extends into the liquid discharge short section 9, the cone 5 is slidably connected with the liquid discharge short section 9, and the cone 5 is away from the liquid discharge short section 9 A conical slide 52 is provided at one end, and the slip 6 can move along the conical slide 52; one end of the center rod 11 is inserted into the liquid discharge short section 9, and the steel ball 10 abuts against the end of the center rod 11 close to the liquid discharge short section 9, so that the liquid in the flow channel of the center rod 11 can run upward and cannot fall back from the center rod 11; the rubber cylinder 12, the cone 13, the leather cup 14, the inner gasket 15 and the outer ring 17 are sequentially sleeved on the outside of the center rod 11 in the direction away from the liquid discharge short section 9, and can slide relative to the center rod 11, and the outer ring 17 and the elastic claw 18 are screwed together. The end of the center rod 11 away from the steel ball 10 extends into the elastic claw 18 and can slide relative to the elastic claw 18; the elastic claw 18 is provided with a right-angle step 181 for clamping with the oil pipe coupling, and the elastic claw 18 is locked by the locking wire 19 so that the right-angle step 181 is not clamped with the oil pipe coupling. When the locking wire 19 contacts the oil pipe coupling and pops open, the elastic claw 18 unlocks the elastic claw 18, and the right-angle step 181 extends into the oil pipe coupling and clamps with the oil pipe coupling, forming the first anchoring at this time; when the center rod 11 When moving in the direction approaching the locking wire 19, the leather cup 14 can move along the conical surface of the cone 13 to abut against the inner wall of the oil pipe, forming a first seal; when the center rod 11 moves in the direction approaching the locking wire 19, the end of the drainage short section 9 away from the cava connector 8 can abut against the rubber sleeve 12, and the rubber sleeve 12 abuts against the inner wall of the oil pipe under the action of pressure, forming a second seal; when the cava 6 expands along the conical inclined surface in the direction away from the axis of the cava 6 until the cava 6 bites with the inner wall of the oil pipe, a second anchoring is formed.

[0026] The multi-stage plunger seater of the present invention has a double anchoring mechanism and a double sealing mechanism, has a large anchoring force, a good sealing effect and a stable performance, and solves the problem that the seater used in the current conventional plunger gas lift process is easily unstuck and moved upward under the condition of the seater being subjected to the bidirectional impact of the upper and lower plungers, resulting in the failure of the process operation.

[0027] The following combination Figure 1-Figure 19 The structure and shape of the downhole seat for the multi-stage plunger provided in this embodiment are described in detail.

[0028] Regarding the shapes and structures of the upper fishing head 1, the upper support rod 2, the upper damping spring 3, and the upper support seat 4, in detail:

[0029] Reference Figure 1 and Figure 2 The upper salvage head 1 is connected to the upper support rod 2 by threads, the upper support rod 2 extends into the upper support seat 4, and can move relative to the upper support seat 4. The upper damping spring 3 is sleeved on the outside of the upper support rod 2, one end of the upper damping spring 3 is connected to the upper salvage head 1, and the other end is connected to the upper support seat 4. The upper support rod 2 and the upper support seat 4 are limited by the lower step on the upper support rod 2. By compressing the upper damping spring 3, the upper support rod 2 can be telescopically operated in the upper support seat 4. The upper salvage head 1, the upper support rod 2, the upper damping spring 3, and the upper support seat 4 constitute an upper damping mechanism, which can effectively buffer the impact of the plunger falling quickly from the upper part to the seat.

[0030] Regarding the shapes and structures of the cone 5, the slip 6, the elastic outer clamp 7, the slip connector 8, and the drainage nipple 9, in detail:

[0031] Reference Figure 1 and Figure 3 The slip 6, slip connector 8, drainage short section 9 and center rod 11 are connected in sequence from top to bottom, the conical body 5 is inserted into the slip 6 and the slip connector 8, and extends into the drainage short section 9, the conical body 5 is slidingly connected with the drainage short section 9, and a conical slide 52 is provided at one end of the conical body 5 away from the drainage short section 9, the slip 6 can move along the conical slide 52, and the elastic outer clamp 7 is sleeved on the outside of the slip 6.

[0032] Specifically, the cone 5 is located below the upper support seat 4, and the upper support seat 4 and the cone 5 are connected by threads. Figure 7 and Figure 8 , through holes 81 are evenly distributed on the slip connector 8, the slip 6 is connected to the slip connector 8 through the through holes 81, and the bottom end of the slip 6 extends into and is connected to the through holes 81. The slip connector 8 is connected to the drainage nipple 9 through threads, and the conical body 5 can run in the central channel of the slip connector 8 and the drainage nipple 9, referring to Fig. 9 and Fig.10 The cone 5 is provided with an upper limit block 51, a chute 91 is provided in the discharge nipple 9, the limit block is slidably connected with the chute 91, and the upper limit block 51 runs and limits in the chute 91. The slip 6 is tightly attached to the cone 5 by the elastic outer clamp 7, and the slip 6 can run along the conical slide 52 during the movement of the cone 5.

[0033] Regarding the shape and structure of the steel ball 10 and the center rod 11, in detail:

[0034] Reference Figure 1 and Figure 4 One end of the center rod 11 is inserted into the liquid discharge nipple 9, and the steel ball 10 abuts against the end of the center rod 11 close to the liquid discharge nipple 9, so that the liquid in the flow channel of the center rod 11 can flow upward but cannot fall back from the center rod 11.

[0035] Specifically, the drainage nipple 9 is connected to the center rod 11 by threads, the upper end of the center rod 11 is chamfered and forms a check valve with the steel ball 10, ensuring that the liquid in the flow channel of the center rod 11 can flow upward but cannot fall back from the center rod 11. The drainage nipple 9 is designed with a drainage hole 92, and the liquid flowing from the bottom to the top in the center rod 11 can be discharged from the drainage hole 92.

[0036] Regarding the shapes and structures of the rubber cylinder 12, cone 13, leather cup 14, inner washer 15, retaining ring 16, outer ring 17, elastic claw 18 and locking wire 19, in detail:

[0037] Reference Figure 1 and Figure 5 The rubber cylinder 12, cone 13, leather cup 14, inner gasket 15 and outer ring 17 are sequentially sleeved on the outside of the center rod 11 in the direction away from the discharge short section 9, and can slide relative to the center rod 11. The outer ring 17 is threadedly connected with the elastic claw 18. The end of the center rod 11 away from the steel ball 10 extends into the elastic claw 18 and can slide relative to the elastic claw 18.

[0038] The elastic claw 18 is provided with a right-angle step 181 for clamping with the oil pipe coupling. The elastic claw 18 is locked by a locking wire 19 so that the right-angle step 181 is not clamped with the oil pipe coupling.

[0039] When the locking wire 19 contacts the tubing coupling and pops open, the elastic claw 18 unlocks the elastic claw 18, and the right-angle step 181 extends into the tubing coupling and is clamped on the tubing coupling, forming the first anchoring. When the slip 6 expands along the conical slope in the direction away from the axis of the slip 6 until the slip 6 engages with the inner wall of the tubing, forming the second anchoring.

[0040] When the center rod 11 moves toward the direction close to the locking wire 19, the leather cup 14 can move along the conical surface of the cone 13 to abut against the inner wall of the oil pipe, forming a first seal; when the center rod 11 moves toward the direction close to the locking wire 19, the end of the drainage nipple 9 away from the slip connector 8 can abut against the rubber sleeve 12, and the rubber sleeve 12 abuts against the inner wall of the oil pipe under the action of pressure, forming a second seal. Specifically, the cone 13 and the leather cup 14 both have inclined surfaces, and the inclined surface of the cone 13 is arranged opposite to the inclined surface of the leather cup 14. The rubber sleeve 12 and the leather cup 14 will be compressed and deformed during the downward movement of the center rod 11, and will be in close contact with the inner wall of the oil pipe to form a seal, respectively, see FIG. Fig.11 The lower end of the center rod 11 is designed with a lower step block 113, which can also be used as a limit for the upward and downward movement of the center rod 11. The elastic claw 18 is provided with a chamfer 182 for abutting against the lower step block 113. The outer ring 17 is connected to the elastic claw 18 by a thread. Figure 1Before the tool enters the well, the elastic claws 18 can be locked together by the locking wire 19. The structure of the locking wire 19 is as follows: Fig.19 As shown, in this embodiment, a pin is provided on the elastic claw 18, and a locking wire 19 is hinged to the pin. The bending part of the locking wire 19 is engaged with another pin, so that the locking wire 19 locks the elastic claw 18.

[0041] In an alternative embodiment, referring to Fig.18 The chamfer 182 of the elastic claw 18 is an inclined surface and has a horizontal edge for limiting to prevent the center rod 11 from moving further downward.

[0042] In an optional embodiment, the present embodiment is further provided with a retaining spring 16, which is sleeved on the center rod 11 and cooperates with the upper groove 111 and the lower groove 112 of the center rod 11 to lock the center rod 11. The inner washer 15 is threadedly connected to the outer ring 17 and is surrounded by a retaining groove 171. The outer ring 17 of the retaining spring 16 extends into the retaining groove 171, and the inner ring of the retaining spring 16 extends into the groove of the center rod 11.

[0043] Regarding the shapes and structures of the lower support seat 20, the lower damping spring 21, the lower support rod 22 and the lower fishing head 23, in detail:

[0044] Reference Figure 1 and Figure 6 The lower salvage head 23 is threadedly connected with the lower support rod 22, and the lower support rod 22 extends into the lower support seat 20 and can move relative to the lower support seat 20; the lower damping spring 21 is sleeved outside the lower support rod 22, one end of the lower damping spring 21 is connected to the lower salvage head 23, and the other end is connected to the lower support seat 20; the lower end of the elastic claw 18 is threadedly connected to the lower support seat 20. The lower support seat 20, the lower damping spring 21, the lower center rod 11, and the lower salvage head 23 form a lower damping mechanism to alleviate the impact of the lower step plunger on the seat.

[0045] The working process of the downhole seat for the multi-stage plunger provided in this embodiment is as follows:

[0046] 1. Delivery process of the downhole seat for the multi-stage plunger provided in this embodiment:

[0047] The delivery pipe string of the multi-stage plunger seater includes, from top to bottom, steel wire, rope cap, weighted rod, jar, delivery bucket, and seater, wherein the steel wire, rope cap, weighted rod, jar, and delivery bucket are all conventional steel wire operation supporting tools.

[0048] First, the two elastic claws 18 of the seat are locked together by the locking wire 19 (such as Figure 1 As shown in the figure, the tool is ensured not to be stuck in the pipe coupling seam during the well entry process, and the seater is smoothly and stably entered into the well without being limited by the entry speed.

[0049] Connect the steel wire, rope cap, weight rod, jar, delivery bucket, and seater in sequence to form a seater steel wire operation delivery pipe string

[0050] 2. Anchoring and sealing process of the downhole seat for the multi-stage plunger provided in this embodiment:

[0051] The tool status during the lowering process of the seat Figure 1 As shown, at this time, the clamping spring is locked with the center rod 11, and the two elastic claws 18 are locked together by the locking wire 19. When the seater delivers the pipe string to 5-8 meters below the designed oil pipe coupling position, the pipe string is stopped.

[0052] Reference Figures 12 to 18 , slowly lift the seater to deliver the pipe string. When the seater passes the designed tubing coupling position, the locking wire 19 will bounce off the tubing coupling, and then the elastic claw 18 will return to a free state (such as Fig.12 As shown), the elastic claw 18 will be anchored in the oil pipe coupling seam. Continue to lift the delivery pipe string, and the suspended weight of the well testing vehicle will fluctuate significantly. At this time, slowly lower the pipe string. First, the elastic claw 18 will be anchored with the oil pipe coupling seam. Since the protrusion below the elastic claw 18 is designed as a right-angle step 181, it will form a stable limit after anchoring with the oil pipe coupling seam and cannot continue to descend. At this time, the weight of the delivery pipe string is all transferred to the center rod 11. The groove of the center rod 11 will separate from the retaining spring 16 under the action of the upper pressure, and the center rod 11 will move downward until the lower step block 113 of the center rod 11 is completely in contact with the elastic claw 18 to form a limit. During the entire operation of the center rod 11, the leather cup 14 will first move along the conical surface of the cone 13 to form a seal with the oil pipe, and then the rubber sleeve 12 will form a seal with the inner wall of the oil pipe under the action of pressure. After the rubber sleeve 12, the leather cup 14 and the oil pipe form a seal, the center rod 11 will just form a limit with the elastic claw 18, and the center rod 11 will no longer move downward. Under the pressure of the delivery pipe string, the cone 5 of the seater continues to move downward, forming a relative movement with the slip 6. The slip 6 will expand outward along the conical inclined surface of the cone 5 until the slip 6 bites with the inner wall of the oil pipe. At this time, the anchoring and sealing of the seater are completed. The slip 6 and the elastic claw 18 are double-anchored with the inner wall of the oil pipe and the seam of the oil pipe coupling, and the rubber sleeve 12 and the leather cup 14 are double-sealed with the inner wall of the oil pipe.

[0053] Use the jar to hit the delivery pipe string, the delivery bucket pin is shortened, and it will be separated from the seat. Slowly lift the delivery pipe string. If there is no obvious change in the hanging weight, it proves that the delivery bucket is separated from the seat. Lift out the delivery pipe string and the seat is sealed.

[0054] III. The process of fishing and unsealing the downhole seat for the multi-stage plunger provided in this embodiment

[0055] The salvage pipe string of the seat device includes: steel wire, rope cap, weight rod, jar and salvage tube.

[0056] The salvage pipe string consisting of steel wire, rope cap, weighted rod, jar and salvage tube is connected and lowered in the wellbore. When the salvage pipe string of the seater is lowered to the upper part of the seater, the salvage bucket will be connected with the salvage head 1 on the seater, and the salvage pipe string will be lifted up. Under the action of the lifting force, the cone 5 will form relative movement with the slip 6. The slip 6 will shrink along the cone slideway 52 of the cone 5 under the action of the elastic outer clamp 7 and release the jam from the inner wall of the oil pipe. The pipe string will continue to be lifted up. When the cone 5 After the limit block runs along the slideway of the drainage nipple 9 to the uppermost end, it will continue to drive the drainage nipple 9 and the center rod 11 to move upward. As the center rod 11 moves upward, the rubber cylinder 12 and the leather cup 14 will be recovered and unsealed under the action of elastic force. When the center rod 11 continues to move upward, the lower step block 113 contacts the outer ring 17. At this time, the center rod 11 will drive the elastic claw 18 to move upward. The elastic claw 18 will be recovered and raised from the oil pipe coupling seam under the action of the upward lifting force. The seater and the oil pipe are completely unstuck.

[0057] Continue to lift the salvage pipe string to salvage the seat out of the wellbore.

[0058] The downhole seat for the multi-stage plunger provided in this embodiment can achieve the purpose of easy casting and catching of the multi-stage seat, and can withstand the bidirectional impact of the upper and lower plungers during operation while preventing the accumulated liquid on the top of the seat from falling back.

[0059] The downhole seat for the multi-stage plunger provided in this embodiment is not limited by the lowering speed during the placement process and is easy to place; the downhole seat for the multi-stage plunger provided in this embodiment has a small unsealing force and is easy to salvage.

[0060] 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 with 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 downhole seat for a multi-stage plunger, characterized in that: include: Cone (5), slip (6), slip connector (8), drainage nipple (9), steel ball (10), center rod (11), rubber cylinder (12), cone (13), leather cup (14), inner washer (15), outer ring (17), elastic claw (18) and locking steel wire (19); The slip (6), the slip connector (8), the drainage nipple (9) and the center rod (11) are connected in sequence; The conical body (5) is inserted into the slip (6) and the slip connector (8) and extends into the drainage nipple (9). The conical body (5) is slidably connected to the drainage nipple (9). A conical slideway (52) is provided at one end of the conical body (5) away from the drainage nipple (9), and the slip (6) can move along the conical slideway (52). One end of the center rod (11) is inserted into the liquid discharge nipple (9), and the steel ball (10) abuts against a port of the center rod (11) close to the liquid discharge nipple (9), so that the liquid in the flow channel of the center rod (11) can flow upwards and cannot fall back from the center rod (11); The rubber cylinder (12), the cone (13), the leather cup (14), the inner gasket (15) and the outer ring (17) are sequentially sleeved on the outside of the center rod (11) in a direction away from the liquid discharge nipple (9) and can slide relative to the center rod (11); the outer ring (17) is threadedly connected to the elastic claw (18); one end of the center rod (11) away from the steel ball (10) extends into the elastic claw (18) and can slide relative to the elastic claw (18); The elastic claw (18) is provided with a right-angle step (181) for clamping with the oil pipe coupling. The elastic claw (18) is locked by the locking steel wire (19) so that the right-angle step (181) is not clamped with the oil pipe coupling. When the locking steel wire (19) contacts the oil pipe coupling and pops open, the elastic claw (18) unlocks the elastic claw (18), and the right-angle step (181) extends into the oil pipe coupling and clamps with the oil pipe coupling, thereby forming a first anchoring. When the center rod (11) moves toward the locking wire (19), the leather cup (14) can move along the conical surface of the cone (13) to abut against the inner wall of the oil pipe, thereby forming a first seal; When the center rod (11) moves toward the locking wire (19), the end of the liquid discharge nipple (9) away from the slip connector (8) can abut against the rubber sleeve (12), and the rubber sleeve (12) abuts against the inner wall of the oil pipe under the action of pressure, thereby forming a second seal; When the slip (6) expands along the conical inclined surface in a direction away from the axis of the slip (6) until the slip (6) engages with the inner wall of the oil pipe, a second anchoring is formed.

2. The downhole seat for the multi-stage plunger according to claim 1, characterized in that: It also includes an upper fishing head (1), an upper support rod (2), an upper damping spring (3) and an upper support seat (4); The upper fishing head (1) is threadedly connected to the upper support rod (2); the upper support rod (2) extends into the upper support seat (4) and is movable relative to the upper support seat (4); The upper shock absorbing spring (3) is sleeved on the outside of the upper support rod (2), one end of the upper shock absorbing spring (3) is connected to the upper fishing head (1), and the other end is connected to the upper support seat (4); The upper support seat (4) is connected to the cone (5).

3. The downhole seat for the multi-stage plunger according to claim 2, characterized in that: It also includes a lower support seat (20), a lower shock absorbing spring (21), a lower support rod (22) and a lower fishing head (23); The lower fishing head (23) is threadedly connected to the lower support rod (22); the lower support rod (22) extends into the lower support seat (20) and is movable relative to the lower support seat (20); The lower shock absorbing spring (21) is sleeved on the outside of the lower support rod (22), one end of the lower shock absorbing spring (21) is connected to the lower fishing head (23), and the other end is connected to the lower support seat (20); The lower end of the elastic claw (18) is connected to the lower support seat (20) via a thread.

4. The downhole seat for the multi-stage plunger according to claim 3, characterized in that: The slip connector (8) is provided with a through hole (81), and the slip (6) is connected to the slip connector (8) via the through hole (81).

5. The downhole seat for the multi-stage plunger according to claim 4, characterized in that: The conical body (5) is provided with an upper limit block (51), a slide groove (91) is provided in the liquid discharge short section (9), and the limit block is slidably connected to the slide groove (91).

6. The downhole seat for the multi-stage plunger according to claim 1, characterized in that: It also includes an elastic outer clamp (7); The elastic outer clamp (7) is sleeved on the outside of the slip (6).

7. The downhole seat for the multi-stage plunger according to claim 6, characterized in that: The drainage nipple (9) is provided with a drainage hole (92) for drainage.

8. The downhole seat for the multi-stage plunger according to claim 7, characterized in that: Also includes a retaining spring (16); The inner gasket (15) is threadedly connected to the outer ring (17) and is surrounded by a clamping groove (171), and the outer ring (17) of the clamping spring (16) extends into the clamping groove (171).

9. The downhole seat for the multi-stage plunger according to claim 8, characterized in that: The center rod (11) is provided with an upper groove (111) and a lower groove (112) for matching with the inner ring of the retaining ring (16).

10. The downhole seat for the multi-stage plunger according to claim 1, characterized in that: The central rod (11) is provided with a lower step block (113), and the elastic claw (18) is provided with a chamfer (182) for abutting against the lower step block (113).

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