A metal expandable open hole packer

Abstract

The application provides a metal expansion type open hole packer, which comprises a center pipe, an expansion cylinder, a first sealing assembly and a second sealing assembly, a sealing cavity is formed between the expansion cylinder and the center pipe in a radial direction, a liquid injection channel is formed in the first sealing assembly, the liquid injection channel is connected with an internal flow channel of the center pipe and the sealing cavity, a pressure compensation mechanism is formed in the first sealing assembly, the pressure compensation mechanism comprises a liquid supplement channel, an annulus above the metal expansion type open hole packer is connected with the sealing cavity through the liquid supplement channel, and liquid in the center pipe can enter the sealing cavity through the liquid injection channel by wellhead pressing, so that the expansion cylinder is expanded in a radial direction until the expansion cylinder is tightly attached to a well wall to complete setting, and the sealing cavity can be supplemented with liquid through the liquid supplement channel when the upper pressure borne by the metal expansion type open hole packer is greater than the pressure of the sealing cavity, so that the metal expansion type open hole packer can continue to be expanded and sealed.

Description

Technical Field

[0001] This invention belongs to the field of well completion technology in the petroleum industry, and specifically relates to a metal expansion open-hole packer. Background Technology

[0002] Open-hole staged fracturing is one of the effective techniques for increasing single-well production and achieving production gains. Compared to compression packers, expansion packers have a larger expansion ratio, a longer sealing section, and greater adaptability to wellbore irregularities, giving them a greater advantage in open-hole stratification.

[0003] However, with the development of ultra-deep wells and hot dry rock, the temperature resistance requirements for packers have reached over 200℃. Currently, most existing open-hole packers use rubber sleeves or steel strip rubber sleeves as sealing units for interlayer separation, which have insufficient high-temperature and high-pressure resistance and reliability. For example, existing open-hole packers have many sealing components, resulting in poor temperature resistance. The small inner diameter of the sealing rubber sleeve leads to a small inner diameter of the downhole tool, making it difficult to perform large-volume acid fracturing and resulting in low operational efficiency. In addition, existing open-hole packers have poor sealing performance and cannot achieve a durable and effective seal under high-temperature environments, resulting in poor reliability and failing to meet the requirements of open-hole staged fracturing in high-temperature and high-pressure wells. Summary of the Invention

[0004] To address the technical problems described above, this invention aims to provide a metal expansion type open-eye packer that significantly enhances temperature resistance and greatly improves the packer's pressure-bearing reliability, enabling the packer to achieve a durable and effective seal under high-temperature conditions.

[0005] To address this, the present invention provides a metal expansion open-hole packer, comprising: a central tube; an expansion cylinder sleeved on the central tube, the upper and lower ends of the expansion cylinder being sealed to the central tube via a first sealing assembly and a second sealing assembly, respectively, and the first sealing assembly being fixedly connected to the central tube, forming a sealing cavity between the expansion cylinder and the central tube radially; an injection channel formed within the first sealing assembly, the injection channel communicating with the internal flow channel of the central tube and the sealing cavity; and a pressure compensation mechanism formed within the first sealing assembly, the pressure compensation mechanism including a replenishment channel, the wellbore annulus above the metal expansion open-hole packer communicating with the sealing cavity via the replenishment channel; wherein, by pressurizing the wellhead, liquid in the central tube can enter the sealing cavity through the injection channel, causing the expansion cylinder to expand radially until it adheres tightly to the well wall to complete the setting, and when the pressure on the metal expansion open-hole packer exceeds the pressure of the sealing cavity, liquid can be replenished to the sealing cavity through the pressure replenishment channel to continue expanding and sealing the metal expansion open-hole packer.

[0006] In one embodiment, the expansion cylinder includes a metal inner cylinder and a rubber outer cylinder sleeved on the metal inner cylinder, wherein the rubber outer cylinder is attached to the outer surface of the metal inner cylinder by vulcanization.

[0007] In one embodiment, the metal inner cylinder includes an expansion section at the axial center and connecting sections at both ends, wherein the thickness of the expansion section is set to be less than the thickness of the connecting sections.

[0008] In one embodiment, the inner diameter of the expansion segment is set to be larger than the inner diameter of the connecting segment, and an arc transition is formed at the connection between the expansion segment and the connecting segment.

[0009] In one embodiment, the outer surface of the metal inner cylinder is provided with a plurality of annular grooves, which are evenly spaced apart in the axial direction.

[0010] In one embodiment, the first sealing assembly includes an upper connector and an upper ring fitted on the upper connector, the upper connector being fixedly connected to the central tube and forming a seal, and the upper end of the metal inner cylinder extending between the upper connector and the upper ring and being fixedly connected to the upper connector.

[0011] In one embodiment, the sidewall of the central tube is provided with a first through hole, and the upper connector is provided with a first flow channel hole communicating with the sealing cavity. The first through hole and the first flow channel hole are connected to form the injection channel.

[0012] In one embodiment, a first check valve is provided in the injection channel.

[0013] In one embodiment, the side wall of the upper ring is provided with a second through hole, and the upper connector is also provided with a second flow channel hole that communicates with the sealing cavity. The second flow channel hole and the first flow channel hole are staggered in the circumferential direction, and the second through hole communicates with the second flow channel hole, thereby forming the liquid replenishment channel.

[0014] In one embodiment, a second one-way valve is provided in the replenishment channel.

[0015] In one embodiment, the second sealing assembly includes a lower connector and a lower end ring fitted on the lower connector, the lower connector forming a seal with the central tube, and the lower end of the metal inner cylinder extending between the lower connector and the lower end ring and being fixedly connected to the lower connector.

[0016] In one embodiment, the lower connector is provided with an axially penetrating injection hole for injecting liquid into the sealed cavity, and the lower end of the injection hole is provided with a plug.

[0017] In one embodiment, anti-protrusion units are provided at both ends of the expansion cylinder. The anti-protrusion unit includes a first anti-protrusion ring, a second anti-protrusion ring, and a third anti-protrusion ring. The first anti-protrusion ring contacts the corresponding upper or lower end ring. The third anti-protrusion ring wraps around the axial end of the rubber outer cylinder. The second anti-protrusion ring is located between the second anti-protrusion ring and the third anti-protrusion ring.

[0018] In one embodiment, the third anti-protrusion ring is configured to expand to accommodate the radial expansion of the expansion cylinder and always wrap around the axial end of the rubber outer cylinder.

[0019] Compared with the prior art, the advantages of this application are:

[0020] The metal-expanded open-hole packer of the present invention uses fewer sealing components, effectively improving its high-temperature resistance. Furthermore, the expansion cylinder has a thinner wall and a larger inner diameter compared to all-rubber packers and steel-belt packers, facilitating high-volume acid fracturing and significantly improving acid fracturing efficiency. Simultaneously, the metal-expanded open-hole packer significantly improves its pressure-bearing reliability through a pressure compensation mechanism. In addition, the metal-expanded open-hole packer achieves a durable and effective seal under high-temperature conditions, meeting the requirements of open-hole fracturing in high-temperature and high-pressure wells. Attached Figure Description

[0021] The invention will now be described with reference to the accompanying drawings.

[0022] Figure 1 The structure of the metal expansion-type naked-eye occluder according to the present invention is schematically shown.

[0023] Figure 2 The setting state of the metal expansion naked-eye packer is schematically shown.

[0024] Figure 3 schematically shown Figure 1 The structure of the anti-surge unit in the metal expansion packer shown.

[0025] Figure 4 schematically shown Figure 3 The anti-surge unit is shown in its open state.

[0026] Figure 5 The diagram schematically illustrates the pressure state of a metal expansion naked-eye packer.

[0027] Figure 6 The diagram schematically illustrates the pressurized state of a metal expansion naked-eye packer.

[0028] In this application, all drawings are schematic and are used only to illustrate the principles of the invention, and are not drawn to scale. Detailed Implementation

[0029] The invention will now be described with reference to the accompanying drawings.

[0030] For ease of understanding, in this application, the end closer to the wellhead is defined as the upper end, upstream end, or similar terminology, while the end farther from the wellhead is defined as the lower end, downstream end, or similar terminology. Furthermore, the direction along the length of the metal expandable open-hole packer is referred to as the longitudinal direction, axial direction, or similar terminology, while the direction perpendicular to it is referred to as the transverse direction, radial direction, or similar terminology.

[0031] Figure 1 The structure of a metal expandable open-hole packer 100 according to the present invention is schematically shown. As shown in Figure 1, the metal expandable open-hole packer 100 includes a central tube 2, an expansion cylinder 3 fitted onto the central tube 2, a first sealing assembly 4 and a second sealing assembly 5 respectively disposed at both ends of the expansion cylinder 3, an injection channel, and a pressure compensation mechanism 8. The expansion cylinder 3 is fitted onto the central tube 2, and the upper end of the expansion cylinder 3 is fixedly connected to the central tube 2 through the first sealing assembly 4 to form a seal, and the lower end of the expansion cylinder 3 is sealed to the central tube 2 through the second sealing assembly 5. Thus, a sealed cavity 6 is formed radially between the expansion cylinder 3 and the central tube 2. The injection channel is formed within the first sealing assembly 4, and the injection channel communicates with the internal flow channel of the central tube 2 and the sealed cavity 6. The pressure compensation mechanism 8 is formed within the first sealing assembly 4, and the pressure compensation mechanism 8 includes a replenishment channel, and the wellbore annulus 101 (see figure) located above the metal expandable open-hole packer 100. Figure 6 It is connected to the sealed cavity 6 through the replenishment channel.

[0032] When the metal expansion packer 100 needs to be set, pressurization at the wellhead allows the liquid in the internal flow channel of the central tube 2 to enter the sealing cavity 6 through the injection channel, thereby continuously increasing the liquid pressure in the sealing cavity 6. This causes the expansion cylinder 3 to gradually expand radially until it adheres tightly to the well wall 1, thus achieving the setting of the metal expansion packer 100. Figure 2 The image shows the setting state of the metal expansion open-eye packer 100. When the metal expansion open-eye packer 100 is subjected to pressure, the pressure compensation mechanism 8 can replenish the sealing cavity 6 with fluid through the pressure replenishment channel. When the pressure is greater than the pressure inside the sealing cavity 6, the metal expansion open-eye packer 100 continues to expand and seal, thereby ensuring the pressure inside the sealing cavity 6 and improving the sealing reliability.

[0033] According to the present invention, such as Figure 1As shown, the expansion cylinder 3 includes a metal inner cylinder 31 and a rubber outer cylinder 32 sleeved on the metal inner cylinder 31. In one embodiment, the rubber outer cylinder 32 is attached to the outer surface of the metal inner cylinder 31 by vulcanization. The rubber outer cylinder 32 is preferably made of a material with high temperature resistance, such as fluororubber or perfluororubber.

[0034] like Figure 1 As shown, the metal inner cylinder 31 includes an expansion section at the axial center and connecting sections at both ends. The thickness of the expansion section is set to be less than the thickness of the connecting sections. This makes the metal inner cylinder 31 easy to expand and deform, while the thicker ends ensure that the deformation is smaller under the same pressure.

[0035] Preferably, inside the metal inner cylinder 31, the inner diameter of the expansion section is set to be larger than the inner diameter of the connecting section, and a smooth transition is formed at the connection between the expansion section and the connecting section by an arc. This can effectively reduce stress concentration when the metal inner cylinder 31 deforms.

[0036] The metal inner cylinder 31 is preferably made of a material with high strength and high tensile strength. As a result, the metal inner cylinder 31 has good ductility.

[0037] According to one embodiment of the present invention, the outer surface of the metal inner cylinder 31 is provided with a plurality of annular grooves (not shown), which are evenly spaced apart in the axial direction. The annular grooves generate stress concentration after expansion, which can significantly improve the contact stress between the metal expandable open hole packer 100 and the wellbore, which is very beneficial to improving the sealing ability and reliability of the metal expandable open hole packer 100.

[0038] According to the present invention, the first sealing assembly 4 includes an upper connector 41 and an upper end ring 42 fitted onto the upper connector 41. The upper connector 41 is fixedly connected to the central tube 2 and forms a seal. The upper end of the metal inner cylinder 31 extends between the upper connector 41 and the upper end ring 42, and the metal inner cylinder 31 is fixedly connected to the upper connector 41.

[0039] In one embodiment, the upper ring 42 and the inner metal cylinder 31 are fixedly connected by a threaded connection. The upper ring 42 and the upper connector 41 are also fixedly connected by a threaded connection. Furthermore, the inner metal cylinder 31 and the upper connector 41 are fixedly connected and sealed by welding. The upper connector 41 is sleeved on the central tube 2, and is fixedly connected to the central tube 2 by welding to form a seal.

[0040] According to the present invention, the side wall of the central tube 2 is provided with a first through hole 21, and the upper connector 41 is provided with a first flow channel hole 411 communicating with the sealing cavity 6. The first through hole 21 and the first flow channel hole 411 communicate with each other, thereby forming an injection channel. Figure 1As shown, the first flow channel hole 411 includes a radial hole segment extending in the radial direction and an axial hole segment extending in the axial direction. The radial hole segment is connected to the axial hole segment. The radial hole segment is connected to the first through hole 21. The axial hole segment is connected to the sealing cavity 6.

[0041] According to one embodiment of the present invention, a first one-way valve 71 is provided in the injection channel. Thus, the injection channel ensures that liquid can only enter the sealing cavity 6 from the internal flow path of the central tube 2, and cannot flow back from the sealing cavity 6 into the central tube 2. This guarantees the continuous sealing of the metal expansion type open-eye packer 100 and effectively improves the reliability of the metal expansion type open-eye packer 100.

[0042] The first one-way valve 71 is preferably disposed within the first flow channel hole 411, and more preferably disposed within the axial section of the first flow channel hole 411.

[0043] According to the present invention, the side wall of the upper ring 42 is provided with a second through hole 421, and the upper connector 41 is also provided with a second flow channel hole 412 communicating with the sealing cavity 6. The second flow channel hole 412 and the first flow channel hole 411 are staggered in the circumferential direction. The second through hole 421 and the second flow channel hole 412 communicate with each other, thereby forming a liquid replenishment channel. Similarly, as Figure 1 As shown, the second flow channel hole 412 includes a radial hole segment extending in the radial direction and an axial hole segment extending in the axial direction. The radial hole segment is connected to the axial hole segment, and the radial hole segment is connected to the second through hole 421. The axial hole segment is connected to the sealing cavity 6.

[0044] According to one embodiment of the present invention, a second one-way valve 81 is provided in the replenishment channel. Thus, the replenishment channel ensures that liquid can only enter the sealing cavity 6 from the internal flow path of the central tube 2, and cannot flow back from the sealing cavity 6 into the central tube 2. This further guarantees the continuous sealing of the metal expansion type open-eye packer 100, thereby further improving the reliability of the metal expansion type open-eye packer 100.

[0045] The second one-way valve 81 is preferably disposed within the second flow channel hole 412, and more preferably disposed within the axial section of the second flow channel hole 412.

[0046] When the metal expandable open-hole packer 100 is expanded and subjected to upper pressure, if the pressure inside the sealing cavity 6 is less than the upper cavity pressure between the metal expandable open-hole packer 100 and the wellbore, the upper cavity can compensate for the pressure in the sealing cavity 6 through the pressure compensation mechanism 8. This increases the positive pressure between the metal inner cylinder 31, the rubber outer cylinder 32, and the wellbore, thereby significantly improving the sealing capacity of the metal expandable open-hole packer 100. It should be understood that the upper cavity here refers to the wellbore annulus 101 above the metal expandable open-hole packer 100 after it has expanded (see...). Figure 6).

[0047] According to the present invention, such as Figure 1 As shown, the second sealing assembly 5 includes a lower connector 51 and a lower end ring 52 fitted onto the lower connector 51, forming a seal between the lower connector 51 and the central tube 2. The lower end of the metal inner cylinder 31 extends between the lower connector 51 and the lower end ring 52, and is fixedly connected to the lower connector 51.

[0048] In one embodiment, the lower end ring 52 is fixedly connected to the metal inner cylinder 31 by threads. The lower connector 51 is also fixedly connected to the lower end ring 52 by threads. The metal inner cylinder 31 and the lower connector 51 are fixed and sealed by welding.

[0049] According to the present invention, the lower connector 51 is fitted onto the central tube 2, and a sealing element 23 is provided between the lower connector 51 and the central tube 2, thereby forming a sliding seal between the lower connector 51 and the central tube 2. That is, a sliding seal is formed between the second sealing assembly 5 and the central tube 2. In this way, during the expansion sealing process of the metal expansion open-eye packer 100, the first sealing assembly 4 is fixedly connected to the central tube 2, while the second sealing assembly 5 can slide axially relative to the central tube 2, thereby ensuring that the telescopic cylinder 3 can effectively expand radially and effectively improving the sealing capability of the metal expansion open-eye packer 100.

[0050] In this embodiment, when the expansion ratio requirement is relatively small, the lower connector 51 and the central tube 2 can also be fixed and sealed by welding. That is, the second sealing component 5 and the central tube 2 are fixedly connected. In this way, the metal expansion type open-eye packer 100 can also expand radially within a certain range to achieve expansion sealing, which can also ensure the sealing capability of the metal expansion type open-eye packer 100.

[0051] According to the present invention, such as Figure 1 As shown, the lower connector 51 is provided with an axially penetrating injection hole 511. The injection hole 511 is used to inject liquid into the sealing cavity 6, and a threaded plug 512 is provided at the lower end of the injection hole. Before leaving the factory, the metal expansion type open-eye packer 100 injects liquid into the sealing cavity 6 through the injection hole 511, and achieves closure and sealing through the threaded plug 512.

[0052] According to the present invention, such as Figure 1 As shown, anti-outburst units 9 are provided at both ends of the expansion cylinder 3. The anti-outburst units 9 are fitted onto the outside of the metal inner cylinder 31 and are located at both ends of the rubber outer cylinder 32, thus forming an upper and lower anti-outburst mechanism. The anti-outburst units 9 can protect the shoulders of the rubber outer cylinder 32 and the metal inner cylinder 31 after the metal expansion open-eye packer 100 is expanded and sealed, thereby improving the pressure-bearing reliability of the metal expansion open-eye packer 100.

[0053] like Figure 3 and Figure 4 As shown, the anti-protrusion unit 9 includes a first anti-protrusion ring 91, a second anti-protrusion ring 92, and a third anti-protrusion ring 93. The first anti-protrusion ring 91 contacts the corresponding upper end ring 42 or lower end ring 52. The third anti-protrusion ring 93 wraps around the axial end of the rubber outer cylinder 32, and the second anti-protrusion ring 92 is located between the second anti-protrusion ring 91 and the third anti-protrusion ring 93. The third anti-protrusion ring 93 is configured to accommodate the radial expansion of the expansion cylinder 3 and always wraps around the axial end of the rubber outer cylinder 32. During installation, the first anti-protrusion ring 91, the second anti-protrusion ring 92, and the third anti-protrusion ring 93 are fitted onto the expansion cylinder 3 in one go.

[0054] like Figure 3 As shown, the upper end face of the first anti-protrusion ring 91 is constructed as a first conical surface, and the lower end face is constructed as an inner stepped surface. At the same time, the lower end face of the upper ring 42 is constructed as an inclined surface that can be adapted to the first conical surface.

[0055] The lower end face of the second anti-protrusion ring 92 is constructed as a second conical surface, and the upper end face is constructed as an outer stepped surface. The inner stepped surface can be adapted to the outer stepped surface, thereby enabling the first anti-protrusion ring 91 and the second anti-protrusion ring 92 to form an adapted mating connection, and the first anti-protrusion ring 91 provides radial and axial limitation for the second anti-protrusion ring 92.

[0056] like Figure 3 As shown, the third anti-protrusion ring 93 is constructed to include a radial extension 931, an axial extension 933, and a connecting portion 932 connecting the radial extension ring and the axial extension ring. The connecting portion 932 forms a certain angle with the radial extension 931, so that the outer end face of the middle connecting portion 932 can be adapted to the second conical surface of the second anti-protrusion ring 92. In the initial state, the axial extension 933 of the third anti-protrusion ring 93 extends axially and wraps around the axial end of the rubber outer cylinder 32.

[0057] like Figure 4 As shown, after the metal expansion packer 100 is expanded, the axial extension 933 of the third anti-protrusion ring 93 expands to accommodate the radial expansion of the telescopic cylinder 3 until the extension direction of the axial extension 933 is consistent with the extension direction of the connecting part, and the axial extension 933 always wraps around the axial end of the rubber outer cylinder 32. Simultaneously, during the expansion process, the first anti-protrusion ring 91 and the second anti-protrusion ring 92 undergo radial deformation (not shown in the figure) under the action of the third anti-protrusion ring 93, effectively providing axial support and limiting the third anti-protrusion ring 93. Therefore, the anti-protrusion unit 9 effectively prevents the ends of the telescopic cylinder 3 from protruding, effectively protecting the shoulders of the rubber outer cylinder 32 and the metal inner cylinder 31, thereby improving the pressure-bearing reliability of the metal expansion packer 100.

[0058] In one embodiment, the first anti-protrusion ring 91, the second anti-protrusion ring 92, and the third anti-protrusion ring 93 may be made of 2Cr13 material.

[0059] The working process of the metal expansion naked-eye occluder 100 according to the present invention is briefly described below.

[0060] like Figure 1 As shown, the metal expansion packer 100 is in the initial state of well entry, and the expansion cylinder 3 is in the initial contraction state. At this time, the external environment is a high temperature state in the wellbore.

[0061] Before fracturing, the metal expandable open-hole packer 100 is set by pressurizing at the wellhead. During pressurization, fluid enters the sealing cavity 6 through the injection channel. With continuous pressurization, the pressure inside the sealing cavity 6 increases, causing the inner metal cylinder 31 and the outer rubber cylinder 32 to gradually expand until the outer rubber cylinder 32 adheres tightly to the well wall 1 and forms a seal, thus completing the packing. During the expansion sealing process, the first anti-outburst ring 91, the second anti-outburst ring 92, and the third anti-outburst ring 93 in the anti-outburst unit 9 expand simultaneously to protect the shoulders of the outer rubber cylinder 32 and the inner metal cylinder 31.

[0062] When fracturing is performed, such as Figure 5 As shown, firstly, the ball is dropped to open the sliding sleeve 15 connected to the lower end of the metal expandable open-hole packer 100. Fracturing fluid enters the wellbore through the side hole of the sliding sleeve 15 to fracture the formation. At this time, the metal expandable open-hole packer 100 is subjected to downward pressure (lower chamber pressure). When the pressure inside the sealing cavity 6 is less than the pressure in the internal flow channel of the central tube 2, fluid can continue to be injected into the sealing cavity 6 through the injection channel to further expand and seal the metal expandable open-hole packer 100, ensuring its sealing reliability. It should be understood that the lower chamber here refers to the annulus 102 in the wellbore below the metal expandable open-hole packer 100 after it has expanded and sealed (see...). Figure 5 ).

[0063] like Figure 6 As shown, when the ball is dropped to open the sliding sleeve 14 connected to the upper end of the metal expansion open-hole packer 100 to fracturing the formation above the metal expansion open-hole packer 100, the metal expansion open-hole packer 100 bears the upper pressure. When the pressure in the upper cavity is greater than the pressure inside the sealing cavity 6, the sealing cavity 6 can be replenished with fluid through the pressure compensation mechanism 8 to continue expanding and sealing the metal expansion open-hole packer 100, thereby improving the packing reliability.

[0064] The metal expansion open-hole packer 100 of the present invention has fewer sealing components, which effectively improves its high-temperature resistance. The expansion cylinder 3 has a thinner wall and a larger inner diameter compared to all-rubber packers and steel-belt packers, facilitating high-volume acid fracturing and significantly improving acid fracturing efficiency. Simultaneously, the metal expansion open-hole packer 100, through the pressure compensation mechanism 8, significantly improves its pressure-bearing reliability. Furthermore, the metal expansion open-hole packer 100 achieves a durable and effective seal under high-temperature conditions, meeting the requirements of open-hole fracturing in high-temperature and high-pressure wells.

[0065] In the description of this invention, it should be understood that the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of the invention, "a plurality of" means two or more, unless otherwise explicitly specified.

[0066] In this invention, unless otherwise explicitly specified and limited, the terms "installation," "connection," "linking," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0067] In the description of this specification, references to terms such as "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0068] Finally, it should be noted that the above description is merely a preferred embodiment of the present invention and does not constitute any limitation on the present invention. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments or make equivalent substitutions for some of the technical features. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A metal expansion-type open-eye occluder, comprising: Central tube (2); An expansion cylinder (3) is fitted onto the central tube. The upper and lower ends of the expansion cylinder are respectively connected to the central tube through a first sealing component (4) and a second sealing component (5). The first sealing component is fixedly connected to the central tube, forming a sealed cavity (6) between the expansion cylinder and the central tube in the radial direction. An injection channel is formed within the first sealing assembly, the injection channel connecting the internal flow channel of the central tube and the sealing cavity; as well as A pressure compensation mechanism (8) is formed within the first sealing assembly. The pressure compensation mechanism includes a fluid replenishment channel. The wellbore annulus (101) above the metal expansion open-hole packer is connected to the sealing cavity through the fluid replenishment channel. The wellhead pressurization allows the liquid in the central tube to enter the sealing cavity through the injection channel, causing the expansion cylinder to expand radially until it adheres tightly to the well wall and completes the setting seal. Furthermore, when the pressure on the metal expansion open hole packer exceeds the pressure of the sealing cavity, the sealing cavity can be replenished with liquid through the replenishment channel to continue expanding and sealing the metal expansion open hole packer. The expansion cylinder includes a metal inner cylinder (31) and a rubber outer cylinder (32) sleeved on the metal inner cylinder. The metal inner cylinder includes an expansion section in the middle of the axial direction and connecting sections at both ends. The thickness of the expansion section is set to be less than the thickness of the connecting section. The outer surface of the metal inner cylinder is provided with a plurality of annular grooves, which are evenly spaced apart in the axial direction. The first sealing assembly includes an upper connector (41) and an upper end ring (42) fitted on the upper connector. The upper connector is fixedly connected to the central tube and forms a seal. The side wall of the central tube is provided with a first through hole (21). The upper connector is provided with a first flow channel hole (411) that communicates with the sealing cavity. The first through hole communicates with the first flow channel hole, thereby forming the liquid injection channel. The upper ring has a second through hole (421) on its side wall, and the upper connector also has a second flow channel hole (412) that communicates with the sealing cavity. The second flow channel hole and the first flow channel hole are staggered in the circumferential direction. The second through hole communicates with the second flow channel hole, thereby forming the liquid replenishment channel. The second sealing assembly includes a lower connector (51) and a lower end ring (52) fitted on the lower connector, forming a seal between the lower connector and the central tube; the lower connector is provided with an axially penetrating injection hole (511) for injecting liquid into the sealed cavity, and the lower end of the injection hole is provided with a plug (512). Anti-protrusion units (9) are provided at both ends of the expansion cylinder. The anti-protrusion unit includes a first anti-protrusion ring (91), a second anti-protrusion ring (92), and a third anti-protrusion ring (93). The first anti-protrusion ring contacts the corresponding upper or lower end ring. The third anti-protrusion ring wraps around the axial end of the rubber outer cylinder. The second anti-protrusion ring is located between the first anti-protrusion ring and the third anti-protrusion ring.

2. The metal expansion type open-eye occluder according to claim 1, characterized in that, The rubber outer cylinder is attached to the outer surface of the metal inner cylinder by vulcanization.

3. The metal expansion type open-eye occluder according to claim 2, characterized in that, The inner diameter of the expansion section is set to be larger than the inner diameter of the connecting section, and an arc transition is formed at the connection between the expansion section and the connecting section.

4. The metal expansion-type open-eye occluder according to any one of claims 1 to 3, characterized in that, The upper end of the metal inner cylinder extends between the upper connector and the upper ring and is fixedly connected to the upper connector.

5. The metal expansion type open-eye occluder according to claim 1, characterized in that, A first check valve (71) is provided in the injection channel.

6. The metal expansion type open-eye occluder according to claim 1, characterized in that, A second check valve (82) is provided in the replenishment channel.

7. The metal expansion-type open-eye occluder according to claim 4, characterized in that, The lower end of the metal inner cylinder extends between the lower connector and the lower end ring and is fixedly connected to the lower connector.

8. The metal expansion type open-eye occluder according to claim 1, characterized in that, The third anti-protrusion ring is configured to adapt to the radial expansion of the expansion cylinder and to always wrap around the axial end of the rubber outer cylinder.

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