A releasable metal packer

Abstract

The present invention relates to the field of oil and gas reservoir exploitation equipment, and in particular to an unsealable metal packer, which aims to alleviate the technical problem that conventional packers in related technologies are prone to failure under complex well conditions such as deep wells and ultra-deep wells. The unsealable metal packer includes a center tube, a sealing mechanism and a limiting mechanism; the sealing mechanism includes a holder, an inner cylinder and an outer cylinder sleeved on the center tube; there are two holders; the inner cylinder and the outer cylinder are both made of beryllium bronze, and the two ends are respectively fixed to the two holders, the middle section of the inner cylinder is in an arc shape convex toward the center tube, the outer cylinder is sleeved on the inner cylinder, and is enclosed with the inner cylinder to form a receiving cavity, and the middle section is wavy; the receiving cavity is filled with filler; the limiting mechanism is arranged on the center tube, and is configured to squeeze the holder under pressure conditions. The sealing mechanism of the packer is resistant to high temperature and high pressure, easy to expand and deform, and can establish an effective seal with the casing, which can meet the use requirements under complex well conditions such as deep wells and ultra-deep wells.

Description

Technical Field

[0001] The invention relates to the technical field of oil and gas reservoir exploitation equipment, and in particular to an unsealed metal packer. Background Art

[0002] As an important tool for downhole operations, packers are widely used in various production processes of oil and gas well exploration and development.

[0003] The development of deep oil and gas resources is characterized by complex and changeable reservoir structural stress, high temperature and high pressure, which places extremely high demands on the performance of the packer. However, conventional packers currently have deficiencies in terms of resistance to high temperature and high pressure, corrosion resistance, aging resistance, and long-term sealing, which makes them prone to failure in complex well conditions such as deep wells and ultra-deep wells. Summary of the invention

[0004] The object of the present invention is to provide a releasable metal packer to alleviate the technical problem in the related art that conventional packers are prone to failure in complex well conditions such as deep wells and ultra-deep wells.

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

[0006] The releasable metal packer provided by the present invention comprises: a central pipe, a sealing mechanism and a limiting mechanism;

[0007] The sealing mechanism comprises a holder, an inner cylinder and an outer cylinder which are sleeved on the central tube;

[0008] The said clamping seats are provided with two and are spaced apart and distributed in the axial direction of the said central tube;

[0009] The inner cylinder and the outer cylinder are both made of beryllium bronze, and both ends of the inner cylinder are respectively fixed to the two clamping seats, wherein the middle section of the inner cylinder between the two clamping seats is in an arc shape convex toward the central tube, and the outer cylinder is sleeved on the inner cylinder and enclosed with the inner cylinder to form a containing cavity, and the middle section of the inner cylinder between the two clamping seats is in a wave shape;

[0010] The accommodating cavity is filled with filler;

[0011] The limiting mechanism is arranged on the central tube and is configured to squeeze the holder under a pressing condition to shorten the distance between the two holders.

[0012] Furthermore, in the axial direction of the central tube, the sealing mechanism and the limiting mechanism are sequentially sleeved on the central tube;

[0013] A pressure transmission hole is provided on the side wall of the central tube;

[0014] The limiting mechanism comprises a limiting cylinder and a positioning cylinder which are coaxially arranged, wherein the limiting cylinder, the positioning cylinder and the central tube together form a first annular cavity which is in communication with the pressure transmission hole;

[0015] In the axial direction of the central tube, the first annular cavity has an upper cavity surface and a lower cavity surface opposite to each other, wherein the upper cavity surface is located in the positioning tube, and the lower cavity surface is located in the limiting tube and is located on the side of the upper cavity surface away from the clamping seat;

[0016] The limiting cylinder is slidably matched with the positioning cylinder, and a first inverted tooth is provided on the outer wall of the limiting cylinder;

[0017] One end of the positioning tube contacts one of the clamping seats, and a second inverted tooth is provided on the inner wall of the positioning tube. The second inverted tooth is configured to mesh with the first inverted tooth under a pressing condition.

[0018] Furthermore, the releasable metal packer further comprises a sitting and hanging mechanism, which is located on the side of the limiting mechanism away from the sealing mechanism in the axial direction of the central pipe, and comprises an upper cone, a lower cone, an outer sheath and slips;

[0019] The upper cone and the lower cone are both sleeved on the central tube and spaced apart in the axial direction of the central tube, wherein the upper cone is fixedly connected to an end of the limiting cylinder away from the clamping seat, and the lower cone is axially fixed to the central tube;

[0020] The outer sheath is sleeved on the upper cone and the lower cone, and one end of the outer sheath is fixedly connected to the upper cone, and the other end is connected to the lower cone via a sealing pin;

[0021] The slips are located between the upper cone, the lower cone, the central tube and the outer jacket.

[0022] Furthermore, a first groove is provided on the outer wall of the central tube, and a first limiting hole is provided on the positioning cylinder;

[0023] The limiting mechanism also includes a first locking block, which is inserted into the first limiting hole. In the radial direction of the central tube, one end of the first locking block contacts the inner wall of the limiting cylinder, and the other end is inserted into the first groove.

[0024] Furthermore, the unsealable metal packer further comprises a balancing mechanism, which is located on a side of the sealing mechanism away from the limiting mechanism in the axial direction of the central tube, and comprises an anti-retraction cap sleeved on the central tube, a first outer tube and a balancing piston;

[0025] The anti-retraction cap is fixedly connected to the central tube and contacts the end surface of the holder;

[0026] The first outer tube is fixedly connected to the anti-retraction cap, and is enclosed with the anti-retraction cap and the central tube to form a second annular cavity, and an external flow hole communicating with the second annular cavity is provided on the side wall thereof;

[0027] An inner flow hole is provided on the side wall of the central tube, and the inner flow hole is communicated with the second annular cavity;

[0028] The balancing piston is located in the second annular cavity and, in the axial direction of the central tube, is also located between the outer flow hole and the inner flow hole.

[0029] Further, the central tube includes an inner tube and an outer tube;

[0030] A matching groove is provided on the outer wall of the inner tube;

[0031] The first outer tube is connected to the inner tube via an unsealing pin;

[0032] One end of the lower cone away from the upper cone is fixedly connected with a stop sleeve;

[0033] The outer tube is sleeved on the inner tube, one end of which is fixedly connected to the anti-retraction cap, and a second locking block is penetrated on the side wall close to the other end of the outer tube;

[0034] In the axial direction of the outer tube, the second locking block is located between the matching groove and the lower cone and contacts the end surface of the lower cone. In the radial direction of the outer tube, one end of the second locking block contacts the inner wall of the stop sleeve and the other end contacts the outer wall of the inner tube.

[0035] Furthermore, a third inverted tooth is provided on the outer wall of the inner tube;

[0036] One end of the stopper sleeve away from the lower cone is fixedly connected to a lower joint, and the lower joint and the stopper sleeve are enclosed to form a receiving groove;

[0037] A first locking ring is provided in the accommodating groove. In the axial direction of the inner tube, the first locking ring is located between the third inverted tooth and the matching groove, and a fourth inverted tooth is provided on its inner wall. The fourth inverted tooth is used to mesh with the third inverted tooth.

[0038] Furthermore, a second groove is provided on the outer wall of the inner tube;

[0039] A third locking block is also provided on the side wall of the outer tube. In the radial direction of the outer tube, one end of the third locking block contacts the inner wall of the limiting cylinder, and the other end is inserted into the second groove.

[0040] Furthermore, one end of the inner tube is fixedly connected to an upper joint;

[0041] The end of the first outer tube away from the anti-retraction cap is fixedly connected to the second outer tube, and the second outer tube is sleeved on the upper joint;

[0042] The unsealing pin is connected to the upper joint and the second outer tube along the radial direction of the inner tube.

[0043] Furthermore, the seating mechanism also includes a spring washer, which is connected between the slip and the outer sleeve, so that the slip has a tendency to move in a radial direction of the central tube toward the central tube.

[0044] In summary of the above technical solutions, the technical effects that can be achieved by the releasable metal packer provided by the present invention are:

[0045] In the releasable metal seal, the limiting mechanism is activated by pressing, so that the seat squeezes the inner cylinder and the outer cylinder; the inner cylinder and the outer cylinder are both made of beryllium bronze, which is resistant to high temperature and high pressure, and can obtain an ideal deformation rate under a smaller load, thereby reducing the sealing force, and wherein the wave structure of the outer cylinder produces radial expansion when subjected to axial compression, thereby increasing the contact stress with the casing, and the arc structure of the inner cylinder produces radial expansion when subjected to axial compression, thereby ensuring the contact seal with the center pipe; in addition, when the inner cylinder and the outer cylinder expand, the filling material in the accommodating cavity is deformed accordingly, thereby further increasing the contact stress between the outer cylinder and the casing, thereby ensuring the reliability of the sealing.

[0046] It can be seen that compared with the existing technology, the sealing mechanism used in the releasable metal packer is resistant to high temperature and high pressure, easy to expand and deform, can establish an effective seal with the casing, and can meet the use requirements under complex well conditions such as deep wells and ultra-deep wells. BRIEF DESCRIPTION OF THE DRAWINGS

[0047] 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.

[0048] Figure 1 A cross-sectional view of a releasable metal packer provided in an embodiment of the present invention;

[0049] Figure 2 for Figure 1 Schematic diagram of the upper section;

[0050] Figure 3 for Figure 1 Schematic diagram of the metal sealing mechanism;

[0051] Figure 4 for Figure 1 A schematic diagram of the middle section of

[0052] Figure 5 for Figure 1 Schematic diagram of the lower section.

[0053] Icon: 1-center tube; 101-pressure transmission hole; 102-inner flow hole; 103-inner tube; 104-outer tube; 105-matching groove;

[0054] 2-card holder; 3-inner cylinder; 4-outer cylinder; 5-filler;

[0055] 6-limiting cylinder; 601-sealing sleeve; 602-locking sleeve;

[0056] 7-positioning cylinder; 701-positioning sleeve; 702-third outer cylinder; 703-connecting sleeve; 704-second locking ring;

[0057] 8-upper cone; 9-lower cone; 10-outer sheath; 11-slip; 12-setting pin; 13-first locking block; 14-anti-retraction cap;

[0058] 15-first outer cylinder; 1501-external flow hole;

[0059] 16-balance piston; 17-unsealing pin; 18-stop sleeve; 19-second locking block; 20-lower joint; 21-first locking ring; 22-third locking block; 23-upper joint; 24-second outer tube; 25-spring pad; 26-ring plug; 27-positioning ring. DETAILED DESCRIPTION

[0060] 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.

[0061] 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.

[0062] 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.

[0063] At present, conventional packers have deficiencies in terms of resistance to high temperature and high pressure, corrosion resistance, aging resistance, and long-term sealing, which makes them prone to failure in complex well conditions such as deep wells and ultra-deep wells.

[0064] In view of this, refer to Figures 1 to 3 The present invention provides an unsealed metal packer, comprising a central tube 1, a sealing mechanism and a limiting mechanism; the sealing mechanism comprises a holder 2, an inner cylinder 3 and an outer cylinder 4 which are sleeved on the central tube 1; two holders 2 are provided and are spaced apart in the axial direction of the central tube 1; the inner cylinder 3 and the outer cylinder 4 are both made of beryllium bronze, and both ends of the two are respectively fixed to the two holders 2, wherein the middle section of the inner cylinder 3 between the two holders 2 is in an arc shape convex toward the central tube 1, the outer cylinder 4 is sleeved on the inner cylinder 3, and is enclosed with the inner cylinder 3 to form a containing cavity, and the middle section of the outer cylinder 4 between the two holders 2 is in a wave shape; the containing cavity is filled with a filling material 5; the limiting mechanism is arranged on the central tube 1, and is configured to squeeze the holder 2 under a pressurizing condition to shorten the distance between the two holders 2.

[0065] In the unsealable metal seal, the limiting mechanism is activated by pressing, so that the seat 2 squeezes the inner cylinder 3 and the outer cylinder 4; the inner cylinder 3 and the outer cylinder 4 are both made of beryllium bronze, which is resistant to high temperature and high pressure, and can obtain an ideal deformation rate under a small load, thereby reducing the sealing force, and wherein the wave structure of the outer cylinder 4 produces radial expansion when subjected to axial compression, which can increase the contact stress with the casing, and the arc structure of the inner cylinder 3 produces radial expansion when subjected to axial compression, which can ensure the contact seal with the center pipe 1; in addition, when the inner cylinder 3 and the outer cylinder 4 expand, the filler 5 in the accommodating cavity is deformed accordingly, thereby further increasing the contact stress between the outer cylinder 4 and the casing, thereby ensuring the reliability of the sealing.

[0066] It can be seen that compared with the existing technology, the sealing mechanism used in the releasable metal packer is resistant to high temperature and high pressure, easy to expand and deform, can establish an effective seal with the casing, and can meet the use requirements under complex well conditions such as deep wells and ultra-deep wells.

[0067] It should be noted here that the filler 5 is a mixture of one or more of corundum, quartz sand, and vulcanized rubber; Figure 3 As shown, the sealing mechanism also includes an annular plug 26. The outer cylinder 4 and the inner cylinder 3 are interference-fitted to form an accommodating cavity, which is sealed by the annular plug 26. The holder 2 is matched with the outer cylinder 4, the inner cylinder 3 and the annular plug 26 by heat-fitting.

[0068] The following combination Figures 1 to 5 The structure and shape of the releasable metal packer provided in this embodiment are described in detail:

[0069] In this embodiment, reference Figure 1The unsealable metal packer also includes a balancing mechanism and a sitting mechanism, and from top to bottom, the balancing mechanism, the sealing mechanism, the limiting mechanism and the sitting mechanism are sequentially sleeved on the central pipe 1.

[0070] Specifically, when the unsealable metal packer is lowered into the casing, the balancing mechanism is used to balance the pressure difference between the inside and outside of the packer to prevent the packer from being unsealed prematurely; the sitting and hanging mechanism operates synchronously when the sealing mechanism is set, so that the packer is clamped on the casing to prevent it from falling into the well.

[0071] Regarding the balancing mechanism, specifically:

[0072] refer to Figure 1 and Figure 2 The central tube 1 is divided into an inner tube 103 and an outer tube 104; the upper end of the inner tube 103 is threadedly connected with an upper joint 23, and a second outer tube 24 is provided on the upper joint 23, and is connected to the second outer tube 24 through an unsealing pin 17; an inner flow hole 102 is provided on the side wall of the inner tube 103; the outer tube 104 is sleeved on the inner tube 103.

[0073] In connection with the above, the balancing mechanism includes an anti-retraction cap 14, a first outer tube 15 and a balancing piston 16; the bottom end of the anti-retraction cap 14 contacts the upper holder 2, the upper end of the outer tube 104 is between the anti-retraction cap 14 and the inner tube 103, the outer tube 104 is threadedly connected to the anti-retraction cap 14 and fixed by a top screw; the upper section of the first outer tube 15 is threadedly connected to the second outer tube 24 and fixed by a top screw, and the lower section is threadedly connected to the anti-retraction cap 14 and fixed by a top screw; the first outer tube 15, the anti-retraction cap 14, the inner tube 103 and the upper joint 23 enclose a second annular cavity, the second annular cavity is connected to the inner flow hole 102, and an outer flow hole 1501 connected to the second annular cavity is provided on the side wall of the first outer tube 15; the balancing piston 16 is in the second annular cavity.

[0074] by Figure 1 For example, when the unsealing metal packer is lowered into the casing, if the pressure inside the packer is greater than the pressure outside the packer, the balance piston 16 slides downward, and vice versa, if the pressure inside the packer is less than the pressure outside the packer, the balance piston 16 slides upward. This design ensures that the packer is not affected by the internal and external pressure difference and the unsealing pin 17 is sheared off in advance.

[0075] Regarding the limit mechanism, specifically:

[0076] refer to Figure 1 , Figure 2 and Figure 4The limiting mechanism includes a limiting cylinder 6 and a positioning cylinder 7 which are coaxially arranged, and from top to bottom, the limiting cylinder 6 includes a sealing sleeve 601 and a locking sleeve 602 in sequence, and the positioning cylinder 7 includes a positioning sleeve 701 and a third outer cylinder 702 in sequence; the top end of the positioning sleeve 701 contacts the base 2 located below, and a first locking block 13 is provided on the side wall of the positioning sleeve 701; the third outer cylinder 702 is sleeved on the positioning sleeve 701 and the limiting cylinder 6, and its upper section is threadedly connected to the positioning sleeve 701, and its lower section is threadedly connected to a connecting sleeve 703, and is also fixed to the connecting sleeve 703 by a top screw; the second locking ring 704 is located between the connecting sleeve 703, the third outer cylinder 702 and the limiting cylinder 6, and a second inverted tooth is formed on the inner wall of the second locking ring 704.

[0077] Continuing from the above, the top end of the sealing sleeve 601 is between the positioning sleeve 701 and the third outer tube 702, and contacts the bottom end of the positioning sleeve 701; the inner wall of the sealing sleeve 601, the bottom wall of the positioning sleeve 701 and the outer wall of the outer tube 104 enclose a first annular cavity, the upper cavity surface of the first annular cavity belongs to the bottom wall of the positioning sleeve 701, and the lower cavity surface belongs to the inner wall of the sealing sleeve 601; a pressure transmission hole 101 is also provided on the side wall of the inner tube 103, and the pressure transmission hole 101 is connected to the first annular cavity; a first groove is provided on the outer wall of the outer tube 104, one end of the first locking block 13 contacts the inner wall of the sealing sleeve 601, and the other end is provided with a chamfer, which is adapted to the first groove and inserted into the first groove; the upper section of the locking sleeve 602 is threadedly connected to the sealing sleeve 601, and a first inverted tooth is provided on the outer wall of the locking sleeve 602, and the first inverted tooth is located above the second locking ring 704.

[0078] Regarding the sitting and hanging mechanism, specifically:

[0079] refer to Figure 4 and Figure 5 The seating mechanism includes an upper cone 8, a lower cone 9, an outer sleeve 10, a slip 11 and a spring washer 25; the upper cone 8 and the lower cone 9 are both sleeved on the center tube 1 and spaced apart in the axial direction of the center tube 1, and the upper cone 8 is threadedly connected to the lower section of the locking sleeve 602 and fixed by a top screw, and the lower cone 9 is axially fixed to the center tube 1; the outer sleeve 10 is sleeved on the upper cone 8 and the lower cone 9, and its upper section is threadedly connected to the upper cone 8 and fixed by a top screw, and the lower section is threadedly connected with a positioning ring 27, and is connected to the lower cone 9 by a sealing pin 12; the slip 11 is located between the upper cone 8, the lower cone 9, the outer tube 104 and the outer sleeve 10; the spring washer 25 is connected between the slip 11 and the outer sleeve 10, so that the slip 11 has a tendency to move in the radial direction of the center tube 1 toward the center tube 1.

[0080] In connection with the above, the lower section of the lower cone 9 is threadedly connected with a stopper sleeve 18, and is also fixed to the stopper sleeve 18 by a top screw; the lower section of the stopper sleeve 18 is threadedly connected with a lower joint 20, and is also fixed to the lower joint 20 by a top screw; the lower joint 20 and the stopper sleeve 18 are enclosed to form a receiving groove, in which a first locking ring 21 is provided, and a fourth inverted tooth is formed on the inner wall of the first locking ring 21; a third inverted tooth and a matching groove 105 are provided on the outer wall of the inner tube 103, and the third inverted tooth is located below the first locking ring 21; a second locking block 19 is pierced on the side wall of the outer tube 104 near its own bottom end, and the second locking block 19 is located above the matching groove 105, and its top side surface contacts the bottom end of the lower cone 9 to prevent the lower cone 9 from descending, one end of which contacts the inner wall of the stopper sleeve 18, and the other end contacts the outer wall of the inner tube 103.

[0081] It should be added here that, regarding the outer cylinder, optionally, it is an integrally molded structure, or consists of three sections from top to bottom, the adjacent sections are threadedly connected and fixed by top screws, and the bottom end of the outer cylinder is in contact with the step surface of the stop sleeve 18; the left end of the second locking block 19 is provided with a chamfer, and the bottom end of the lower cone 9 is provided with an inclined surface, and the inclined surface and the chamfered surface of the second locking block 19 form an inclined wedge structure.

[0082] When using the releasable metal packer, refer to Figures 1 to 5 , connected with the oil pipe through the upper joint 23, and lowered into the casing. During the lowering process, the balancing mechanism balances the pressure difference between the inside and outside of the packer; after the packer is lowered to the specified position of the casing, it is pressurized from the oil pipe, and the liquid flows from the pressure transmission hole 101 to the first annular cavity. At this time, the liquid pressure acts on the sealing sleeve 601 and the positioning sleeve 701, exerting downward and upward forces on the sealing sleeve 601 and the positioning sleeve 701 respectively; due to the existence of the first locking block 13 and the sealing pin 12, the positioning sleeve 701 cannot move upward, and the sealing sleeve 601 has a downward trend. After the liquid pressure reaches the shear value of the sealing pin 12, the sealing pin 12 is sheared, and at this time, the sealing sleeve 601 drives the locking sleeve 602, the upper cone 8, the outer sleeve 10 and the positioning ring 27 to move downward synchronously.

[0083] Continuing from the above, after the sealing sleeve 601 moves downward for a certain distance, the limit on the first locking block 13 is released. At this time, under the action of the hydraulic pressure, the first locking block 13 is separated from the first groove, the positioning sleeve 701 moves upward, squeezes the sealing mechanism, and at the same time drives the third outer cylinder 702, the connecting sleeve 703 and the second locking ring 704 to move upward; as the hydraulic pressure continues to increase, the upper cone 8 squeezes the slip 11, so that the slip 11 moves radially along the conical surface of the upper cone 8 and the lower cone 9 and then anchors on the inner wall of the casing to achieve sitting. After the sealing mechanism is squeezed, the outer cylinder 4 and the inner cylinder 3 expand, and the outer cylinder 4 abuts against the inner wall of the casing to achieve sitting; during the continuous movement of the sealing sleeve 601 and the positioning sleeve 701, the second locking ring 704 and the first inverted tooth change from approaching to biting, and after the positioning ring 27 moves to contact with the top of the stopper sleeve 18, the limiting cylinder 6 moves into place, and at this time, the tooth bite between the second locking ring 704 and the locking sleeve 602 keeps the slip 11 and the sealing mechanism in a locked state.

[0084] Continuing with the above, when it is necessary to unseal, the oil pipe is lifted, and after the unsealing pin 17 is cut off, the inner pipe 103 is driven to move upward through the oil pipe. When the inner pipe 103 moves to the matching groove 105 and is opposite to the second locking block 19, the second locking block 19 is pushed out under the push of the sitting and hanging mechanism, and one end of the second locking block 19 is inserted into the matching groove 105, thereby releasing the limit on the lower cone 9; as it continues to be lifted, the inner pipe 103 drives the outer pipe 104 to move upward through the second locking block 19, and the anti-retraction cap 14 fixedly connected to the outer pipe 104 also moves upward. In this way, the sealing mechanism and the sitting and hanging mechanism lose their limits, and the outer tube 9 The body 4 and the inner cylinder 3 contract to release the seal, and under the action of the restoring force of the spring pad 25, the slip 11 contracts to release the seat, thereby realizing the unsealing of the packer; when the outer step on the outer tube 104 moves up to its lower section and contacts the inner step of the lower cone 9, the outer tube 104 drives the seat mechanism to move upward synchronously, and the limiting mechanism, the sealing mechanism and the balancing mechanism also move upward. At the same time, the fourth inverted tooth on the first locking ring 21 engages with the third inverted tooth on the inner tube 103 to form a horse tooth buckle structure, which further prevents the seat mechanism from falling off from the center pipe 1. In this way, the packer can be taken out of the well.

[0085] Preferably, reference Figure 2, a second groove is provided on the outer wall of the inner tube 103; a third locking block 22 is also provided on the side wall of the outer tube 104. In the radial direction of the outer tube 104, one end of the third locking block 22 contacts the inner wall of the limiting cylinder 6, and the other end is provided with a chamfer, adapted to the second groove, and inserted into the second groove. With this design, in the initial state, the third locking block 22 prevents the inner tube 103 and the outer tube 104 from producing relative axial movement, thereby reducing the load of the unsealing pin 17 and avoiding early unsealing due to the shearing of the unsealing pin 17; in addition, the gap between the third locking block 22 and the side wall of the outer tube 104, the gap between the inner tube 103 and the outer tube 104, and the gap between the outer tube 104 and the sealing sleeve 601 cooperate to establish a flow channel, so that the pressure transmission hole 101 is connected with the first annular cavity.

[0086] 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 releasable metal packer, characterized in that: include: A central tube (1), a sealing mechanism and a limiting mechanism; The sealing mechanism comprises a holder (2) sleeved on the central tube (1), an inner cylinder (3) and an outer cylinder (4); The clamping seats (2) are provided with two and are spaced apart and distributed in the axial direction of the central tube (1); The inner cylinder (3) and the outer cylinder (4) are both made of beryllium bronze, and both ends of the inner cylinder (3) are respectively fixed to the two clamping seats (2), wherein the middle section of the inner cylinder (3) between the two clamping seats (2) is in an arc shape convex toward the central tube (1), and the outer cylinder (4) is sleeved on the inner cylinder (3) and enclosed with the inner cylinder (3) to form a containing cavity, and the middle section of the inner cylinder (4) between the two clamping seats (2) is in a wave shape; The accommodating cavity is filled with a filling material (5); The limiting mechanism is arranged on the central tube (1) and is configured to squeeze the clamping seat (2) under a pressing condition so as to shorten the distance between the two clamping seats (2); In the axial direction of the central tube (1), the sealing mechanism and the limiting mechanism are sequentially sleeved on the central tube (1); A pressure transmission hole (101) is provided on the side wall of the central tube (1); The limiting mechanism comprises a limiting cylinder (6) and a positioning cylinder (7) which are coaxially arranged, and the limiting cylinder (6), the positioning cylinder (7) and the central tube (1) together form a first annular cavity which is in communication with the pressure transmission hole (101); In the axial direction of the central tube (1), the first annular cavity has an upper cavity surface and a lower cavity surface opposite to each other, wherein the upper cavity surface is located in the positioning cylinder (7), and the lower cavity surface is located in the limiting cylinder (6) and is located on the side of the upper cavity surface away from the holder (2); The limiting cylinder (6) is slidably matched with the positioning cylinder (7), and a first inverted tooth is provided on the outer wall of the limiting cylinder (6); One end of the positioning tube (7) contacts one of the clamping seats (2), and a second inverted tooth is provided on the inner wall of the positioning tube (7), wherein the second inverted tooth is configured to mesh with the first inverted tooth under a pressing condition.

2. The releasable metal packer according to claim 1, characterized in that: The releasable metal packer further comprises a seating mechanism, which is located on a side of the limiting mechanism away from the sealing mechanism in the axial direction of the central pipe (1), and comprises an upper cone (8), a lower cone (9), an outer sheath (10) and slips (11); The upper cone (8) and the lower cone (9) are both sleeved on the central tube (1) and spaced apart in the axial direction of the central tube (1), wherein the upper cone (8) is fixedly connected to an end of the limiting cylinder (6) away from the holder (2), and the lower cone (9) is axially fixed to the central tube (1); The outer sheath (10) is sleeved on the upper cone (8) and the lower cone (9), and one end of the outer sheath is fixedly connected to the upper cone (8), and the other end is connected to the lower cone (9) via a setting pin (12); The slip (11) is located between the upper cone (8), the lower cone (9), the central tube (1) and the outer sheath (10).

3. The releasable metal packer according to claim 2, characterized in that: A first groove is provided on the outer wall of the central tube (1), and a first limiting hole is provided on the positioning cylinder (7); The limiting mechanism further comprises a first locking block (13), the first locking block (13) being inserted into the first limiting hole, and in the radial direction of the central tube (1), one end of the first locking block (13) is in contact with the inner wall of the limiting cylinder (6), and the other end is inserted into the first groove.

4. The releasable metal packer according to claim 2, characterized in that: The unsealable metal packer further comprises a balancing mechanism, which is located on a side of the sealing mechanism away from the limiting mechanism in the axial direction of the central tube (1), and comprises an anti-retraction cap (14) sleeved on the central tube (1), a first outer tube (15) and a balancing piston (16); The anti-retraction cap (14) is fixedly connected to the central tube (1) and contacts the end surface of the holder (2); The first outer tube (15) is fixedly connected to the anti-retraction cap (14), and is enclosed with the anti-retraction cap (14) and the central tube (1) to form a second annular cavity, and an external flow hole (1501) communicating with the second annular cavity is provided on its side wall; An inner flow hole (102) is provided on the side wall of the central tube (1), and the inner flow hole (102) is communicated with the second annular cavity; The balancing piston (16) is located in the second annular cavity and, in the axial direction of the central tube (1), is also located between the outer flow hole (1501) and the inner flow hole (102).

5. The releasable metal packer according to claim 4, characterized in that: The central tube (1) comprises an inner tube (103) and an outer tube (104); A matching groove (105) is provided on the outer wall of the inner tube (103); The first outer tube (15) is connected to the inner tube (103) via an unsealing pin (17); One end of the lower cone (9) away from the upper cone (8) is fixedly connected with a stopper sleeve (18); The outer tube (104) is sleeved on the inner tube (103), one end of which is fixedly connected to the anti-retraction cap (14), and a second locking block (19) is penetrated on the side wall close to the other end thereof; In the axial direction of the outer tube (104), the second locking block (19) is located between the matching groove (105) and the lower cone (9), and contacts the end surface of the lower cone (9); in the radial direction of the outer tube (104), one end of the second locking block (19) contacts the inner wall of the stop sleeve (18), and the other end contacts the outer wall of the inner tube (103).

6. The releasable metal packer according to claim 5, characterized in that: The outer wall of the inner tube (103) is provided with third inverted teeth; One end of the stopper sleeve (18) away from the lower cone (9) is fixedly connected to a lower joint (20), and the lower joint (20) and the stopper sleeve (18) are combined to form a receiving groove; A first locking ring (21) is provided in the receiving groove. In the axial direction of the inner tube (103), the first locking ring (21) is located between the third inverted tooth and the matching groove (105), and a fourth inverted tooth is provided on its inner wall. The fourth inverted tooth is used to mesh with the third inverted tooth.

7. The releasable metal packer according to claim 5, characterized in that: A second groove is provided on the outer wall of the inner tube (103); A third locking block (22) is also provided on the side wall of the outer tube (104); in the radial direction of the outer tube (104), one end of the third locking block (22) contacts the inner wall of the limiting cylinder (6), and the other end is inserted into the second groove.

8. The releasable metal packer according to claim 5, characterized in that: One end of the inner tube (103) is fixedly connected to an upper joint (23); One end of the first outer tube (15) away from the anti-retraction cap (14) is fixedly connected to a second outer tube (24), and the second outer tube (24) is sleeved on the upper joint (23); The unsealing pin (17) is connected to the upper joint (23) and the second outer tube (24) along the radial direction of the inner tube (103).

9. The releasable metal packer according to claim 5, characterized in that: The hanging mechanism further comprises a spring washer (25), wherein the spring washer (25) is connected between the slip (11) and the outer sleeve (10), so that the slip (11) has a tendency to move in a radial direction of the central tube (1) toward the central tube (1).

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