Expandable packer

Abstract

The present invention provides an expandable-tube packer, which comprises a liner, an expandable tube, a limiting component and a pressure-holding nipple. Wherein, through holes are formed in the tube wall of the liner; the expandable tube is sleeved outside the liner and can move axially along the liner. The expandable tube is a metal tube, and both ends of the expandable tube are hermetically connected to the liner respectively, and an expansion annulus is formed between the expandable tube and the liner, and the expansion annulus is communicated with the through holes; the limiting component comprises a first limiting member and a second limiting member sleeved on the liner, and both the first limiting member and the second limiting member are detachably connected to the liner, and both ends of the expandable tube can respectively abut against the first limiting member and the second limiting member; the pressure-holding nipple is detachably connected to the lower end of the liner, the pressure-holding nipple has an axial channel communicating with the liner, and a setting part for setting a pressure-holding ball is arranged in the axial channel. The expandable-tube packer provided by the present invention can achieve rapid formation isolation without using an expansion cone or mechanical action, and has the advantage of being able to resist high external pressure.

Description

Technical Field

[0001] The present invention relates to the technical field of oil and gas drilling, and particularly to an expandable tubular packer. Background Art

[0002] With the progress of oil extraction, after an oil well has been produced for a certain stage, the productivity and permeability decrease. In order to increase the well output, a fracturing method is usually adopted for production enhancement operations. The higher the fracturing pressure, the larger and deeper the cracks generated in the formation after fracturing, and the more obvious the effect of increasing production. Since an oil well is divided into many production layers, in order not to interfere with the operation and construction of other production layers, a layered fracturing method is generally adopted during fracturing, and a packer is used to isolate the production layer to be fractured. In this way, the operation and construction of other production layers will not be interfered. The specific operation steps are as follows: first, lower the packer to the designated position along with the pipe string, then perform the isolation of the packer to isolate the production layer to be fractured, and then perform fracturing. The commonly used packers at present mainly include: oil and water encounter packers and mechanical packers.

[0003] The oil and water encounter packer adopts a special rubber structure and will expand in the case of encountering oil or water to isolate the pipe wall and play a blocking role. However, the whole process takes a long time and cannot effectively block high pressure.

[0004] The mechanical packer is to push the rubber component to deform through mechanical action for isolation. This structure relies on mechanical action and the deformation of the rubber. Once the action is not in place, it is very easy to fail, which affects the production of the whole well.

[0005] Now, in order to obtain higher productivity, the fracturing pressure is getting higher and higher, and the operation interval time of fracturing is getting shorter and shorter. This requires the packer to have a high external pressure resistance and the ability to quickly isolate the formation. However, the commonly used packers at present cannot meet the above operation requirements. Summary of the Invention

[0006] The purpose of the present invention is to provide an expandable tubular packer that can resist high external pressure and quickly isolate the formation.

[0007] To achieve the above purpose, the present invention provides an expandable tubular packer, which includes:

[0008] A liner, having a through hole formed in its pipe wall;

[0009] An expandable tube, sleeved outside the liner and capable of axially moving along the liner. The expandable tube is a metal tube, and both ends of the expandable tube are hermetically connected to the liner, and an expansion annulus is formed between the expandable tube and the liner, and the expansion annulus is communicated with the through hole;

[0010] The limiting component includes a first limiting member and a second limiting member sleeved on the liner, and both the first limiting member and the second limiting member are detachably connected to the liner. The two ends of the expansion tube can respectively abut against the first limiting member and the second limiting member.

[0011] The pressure-holding nipple is detachably connected to the lower end of the liner. The pressure-holding nipple has an axial channel communicating with the liner, and a setting portion for setting a pressure-holding ball is provided in the axial channel.

[0012] For the expansion tube packer as described above, tube fixing blocks are respectively connected to the two ends of the expansion tube. The tube fixing blocks are sleeved outside the liner and can move axially along the liner, and a first sealing ring is provided between the tube fixing blocks and the liner.

[0013] For the expansion tube packer as described above, the expansion tube and the tube fixing block are connected by threads, and a second sealing ring is provided between the tube fixing block and the expansion tube.

[0014] For the expansion tube packer as described above, the first limiting member is a coupling. The coupling is provided with an internal thread, and an external thread is provided on the outer peripheral surface of the upper part of the liner. Through the screwing fit of the internal thread and the external thread, the coupling is connected to the liner.

[0015] For the expansion tube packer as described above, the liner can be connected to the tubing through the coupling.

[0016] For the expansion tube packer as described above, the second limiting member includes:

[0017] An anchoring housing is sleeved outside the liner. An accommodation cavity is provided inside the anchoring housing. The inner wall surface of the accommodation cavity is an expanded diameter conical surface. A threaded hole communicating with the accommodation cavity is opened at one end of the anchoring housing facing away from the expansion tube, and a bolt is screwed in the threaded hole.

[0018] An anchoring ring is arranged in the accommodation cavity. The outer peripheral surface of the anchoring ring is a conical surface adapted to the inner wall surface of the accommodation cavity. Through the screwing fit of the bolt and the threaded hole, the bolt can push the anchoring ring to move, and the movement of the anchoring ring can clamp the liner.

[0019] For the expansion tube packer as described above, the setting portion is a stop ring with a central hole formed by the circumferential inward contraction of the lower end surface of the axial channel. The inner diameter of the stop ring is smaller than the diameter of the pressure-holding ball.

[0020] The expandable-tube packer as described above, wherein the bottom of the axial channel is in the shape of a funnel with a wider upper part and a narrower lower part, the diameter of the bottom of the axial channel is smaller than the diameter of the pressure-holding ball, and the setting part is formed at the bottom of the axial channel.

[0021] The expandable-tube packer as described above, wherein a plurality of the through holes are radially formed in the tube wall of the liner.

[0022] The expandable-tube packer as described above, wherein the plurality of through holes are arranged at equal intervals.

[0023] Compared with the prior art, the advantages of the present invention are as follows:

[0024] For the expandable-tube packer provided by the present invention, the pressure-holding short joint is set by the pressure-holding ball, so that liquid or gas directly enters the expansion annulus, the pressure in the expansion annulus continuously increases, and the expandable tube begins to expand to seal the formation. There is no need for an expansion cone or mechanical action, which is simple and convenient, and rapid formation sealing is achieved.

[0025] For the expandable-tube packer provided by the present invention, the expandable tube is made of a metal tube, so that the expandable-tube packer has the advantage of being able to resist high external pressure.

[0026] For the expandable-tube packer provided by the present invention, by arranging the first limiting member and the second limiting member, the expandable tube can be effectively prevented from moving during the process of being lowered into the well or before expansion. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] The following drawings are only intended to illustrate and explain the present invention schematically and do not limit the scope of the present invention. Among them:

[0028] Figure 1 is a schematic cross-sectional structure view of the expandable-tube packer of the present invention;

[0029] Figure 2 is Figure 1 an enlarged structure view of part A in

[0030] Figure 3 is Figure 1 a structure view of the second limiting member in the expandable-tube packer shown in

[0031] Figure 4 is Figure 1 a structure view of the expandable-tube packer shown in the using state.

[0032] Description of the reference numerals in the drawings:

[0033] 1. Liner; 11. Through hole; 2. Expansion tube; 21. Expansion annulus; 3. Pressure buildup nipple; 31. Setting part; 32. Pressure buildup ball; 4. Pipe fixing block; 5. First sealing ring; 6. Second sealing ring; 7. Coupling; 8. Second limiting member; 81. Anchoring housing; 812. Accommodation cavity; 813. Threaded hole; 82. Bolt; 83. Anchoring ring; 100. Oil pipe; 200. Formation. Detailed implementation manners

[0034] For a clearer understanding of the technical solutions, objectives, and effects of the present invention, the specific implementation manners of the present invention will now be described in conjunction with the accompanying drawings.

[0035] As Figure 1 and Figure 2As shown in the figure, the present invention provides an expandable tube packer, which includes a liner 1, an expandable tube 2, a limiting assembly, and a pressure holding nipple 3. Among them, through holes 11 are provided on the tube wall of the liner 1; the expandable tube 2 is sleeved outside the liner 1 and can move axially along the liner 1. The expandable tube 2 is a metal tube, and both ends of the expandable tube 2 are hermetically connected to the liner 1, and an expansion annulus 21 is formed between the expandable tube 2 and the liner 1. The expansion annulus 21 is communicated with the through holes 11. The liquid or gas entering the liner 1 can enter the expansion annulus 21 through the through holes 11. Since both ends of the expandable tube 2 are hermetically connected to the liner 1, the liquid or gas will not flow out of the expansion annulus 21. The continuous inflow of the liquid or gas into the expansion annulus 21 expands the expandable tube 2 to seal off the formation 200. Compared with a rubber tube, the metal tube has better compressive performance and can effectively improve the external pressure resistance of the expandable tube packer. Compared with traditional oil- and water-encountering packers, the expansion time of the metal tube is short, which speeds up the formation sealing speed. Preferably, the expandable tube 2 is made of stainless steel or low-carbon steel; the limiting assembly includes a first limiting member and a second limiting member 8 sleeved on the liner 1, and both the first limiting member and the second limiting member 8 are detachably connected to the liner 1. Both ends of the expandable tube 2 can respectively abut against the first limiting member and the second limiting member 8. Since the expandable tube 2 is a metal tube, its length will decrease after expansion, that is, the expandable tube 2 will contract axially along the liner 1. The setting of the first limiting member and the second limiting member 8 can not only prevent the offset of the expandable tube packer during operation, but also prevent the expandable tube 2 from moving along the liner 1 during lowering or lifting, resulting in situations such as the offset of the formation sealing position 200 or the detachment from the liner 1, thus ensuring the accuracy of the expandable tube packer in sealing off the formation 200; the pressure holding nipple 3 is detachably connected to the lower end of the liner 1. The pressure holding nipple 3 can be connected to the liner 1 through a coupling or directly screwed onto the lower end of the liner 1. The pressure holding nipple 3 has an axial channel communicating with the liner 1, and a setting portion 31 for seating a pressure holding ball 32 is provided in the axial channel, that is, the pressure holding ball 32 can be in sealing cooperation with the setting portion 31. Through the sealing cooperation between the pressure holding ball 32 and the setting portion 31, the liquid or gas cannot continue to flow downward through the axial channel, and the liquid or gas stored in the liner 1 can only enter the expansion annulus 21 through the through holes 11, thereby realizing the sealing off of the formation 200. Preferably, both the pressure holding nipple 3 and the pressure holding ball 32 are made of drillable materials, such as hard aluminum materials or copper materials, so that when further drilling is required, drilling operations can be carried out.

[0036] Specifically, as Figure 1 and Figure 4As shown, during use, the expandable-tube packer is connected to the tubing 100 and lowered into the well together with the tubing 100. After the expandable-tube packer is lowered to the sealing position, a pressure-holding ball 32 is dropped from the wellhead. The pressure-holding ball 32 enters the pressure-holding nipple 3 through the liner 1 and is sealingly connected to the setting part 31, so that the bottom of the expandable-tube packer is blocked. Since the mud pump of the drilling rig continuously injects liquid into the pipe string, the expandable-tube packer starts to hold pressure. The liquid in the liner 1 will flow into the expansion annulus 21 through the through holes 11. As the liquid is continuously injected, the pressure in the expansion annulus 21 continues to rise, and the expandable tube 2 starts to expand. When the pressure reaches the preset value, by controlling the mud pump of the drilling rig, the pressure in the expansion annulus 21 is no longer allowed to continue to increase, and the pressure in the expansion annulus 21 is maintained at the preset value for a period of time to ensure the successful isolation of the high-pressure formation 200. After that, by controlling the mud pump of the drilling rig, the expansion annulus 21 starts to release pressure, and the isolation of the entire formation 200 is completed.

[0037] It should be noted that the working process of controlling the mud pump of the drilling rig to pressurize or release pressure belongs to the prior art and will not be elaborated here. It is also possible to introduce gas into the expandable-tube packer to continuously increase the pressure in the expansion annulus 21, and the expandable tube 2 starts to expand.

[0038] Furthermore, in order to improve the efficiency of gas or liquid entering the expansion annulus 21, a plurality of through holes 11 are radially formed in the wall of the liner 1, so that gas or liquid can fill the expansion annulus 21 more quickly, and thus the expandable tube 2 can expand and isolate the formation 200 more quickly.

[0039] Still further, the plurality of through holes 11 are arranged at equal intervals. Preferably, two parallel circles of through holes 11 are provided on the wall of the liner 1, and each circle is provided with three through holes 11, that is, the included angle between two adjacent through holes 11 in the same circle is 120 degrees, so that liquid or gas can uniformly fill the expansion annulus 21.

[0040] The expandable-tube packer provided by the present invention seats and holds pressure on the pressure-holding nipple 3 through the pressure-holding ball 32, so that liquid or gas is directly introduced into the expansion annulus 21, the pressure in the expansion annulus 21 continues to rise, and the expandable tube 2 starts to expand and isolate the formation 200. It does not require an expansion cone or mechanical action, is simple and convenient, realizes the rapid isolation of the formation 200, and the expandable tube 2 is made of a metal tube, so that the expandable-tube packer has the advantage of being able to resist high external pressure.

[0041] In an embodiment of the present invention, as Figure 1As shown in the figure, pipe fixing blocks 4 are respectively connected to both ends of the expansion pipe 2. The pipe fixing blocks 4 are sleeved outside the liner 1 and can move axially along the liner 1. That is, the expansion pipe 2 is connected to the liner 1 through the pipe fixing blocks 4, and a first sealing ring 5 is provided between the pipe fixing blocks 4 and the liner 1. That is, the expansion pipe 2 is hermetically connected to the liner 1 through the pipe fixing blocks 4 and the first sealing ring 5. Preferably, the first sealing ring 5 is arranged above the through hole 11, and the gap between the pipe fixing blocks 4 and the liner 1 is sealed by the first sealing ring 5. When the pipe fixing blocks 4 move relative to the liner 1 along with the expansion pipe 2, it can also ensure that the connection between the pipe fixing blocks 4 and the liner 1 is always hermetically connected, thus ensuring the sealing performance of the expansion annulus 21.

[0042] Furthermore, the expansion pipe 2 and the pipe fixing blocks 4 are connected by threads. The threaded connection is simple and convenient, and a second sealing ring 6 is provided between the pipe fixing blocks 4 and the expansion pipe 2. The connection between the pipe fixing blocks 4 and the expansion pipe 2 is sealed by the first sealing ring 5, so that the connection between the pipe fixing blocks 4 and the expansion pipe 2 is always hermetically connected, thereby further ensuring the sealing performance of the expansion annulus 21.

[0043] Of course, the expansion pipe 2 can also be welded to the pipe fixing blocks 4 as a whole, or the pipe fixing blocks 4 are connected to the expansion pipe 2 through fixing pins.

[0044] In an embodiment of the present invention, as Figure 1 shown, the first limiting member is a coupling 7. The coupling 7 is provided with internal threads, and the outer peripheral surface of the upper part of the liner 1 is provided with external threads. Through the screw-threaded engagement of the internal threads and the external threads, the coupling 7 is connected to the liner 1. The top surface of the pipe fixing member connected to the upper end of the expansion pipe 2 abuts against the bottom surface of the coupling 7. When lifting the expansion pipe packer, the upward movement of the expansion pipe 2 is restricted by the coupling 7, so that the expansion pipe packer can be smoothly lifted. Moreover, when the expansion pipe 2 expands, the coupling 7 can also restrict the movement of the expansion pipe 2, so that the expansion pipe packer can smoothly seal the formation 200.

[0045] Furthermore, the liner 1 can be connected to the oil pipe 100 through the coupling 7, so that the connection between the expansion pipe packer and the oil pipe 100 is simple and convenient.

[0046] In an embodiment of the present invention, as Figure 1 and Figure 3As shown in the figure, the second limiting member 8 includes an anchoring housing 81 and an anchoring ring 83. Among them, the anchoring housing 81 is sleeved outside the liner 1. An accommodation cavity 812 is provided inside the anchoring housing 81. The inner wall surface of the accommodation cavity 812 is an expanded-diameter conical surface. One end of the anchoring housing 81 facing away from the expansion tube 2 is provided with a threaded hole 813 communicating with the accommodation cavity 812, and a bolt 82 is screwed into the threaded hole 813; the anchoring ring 83 is arranged in the accommodation cavity 812. The outer peripheral surface of the anchoring ring 83 is a conical surface adapted to the inner wall surface of the accommodation cavity 812. Through the screwing fit of the bolt 82 and the threaded hole 813, the bolt 82 can push the anchoring ring 83 to move, and the movement of the anchoring ring 83 can clamp the liner 1. Specifically, rotate the bolt 82 to continuously screw the bolt 82 into the threaded hole 813 to abut against the anchoring ring 83 and move it towards the expansion tube 2. At this time, since the inner wall surface of the accommodation cavity 812 is smaller closer to the expansion tube 2, the anchoring ring 83 will shrink under the action of the inner wall surface of the accommodation cavity 812 and tightly clamp the liner 1. By adjusting the length of the bolt 82 screwed into the threaded hole 813, the degree of clamping the liner 1 by the anchoring housing 81 can be adjusted.

[0047] In addition, since the first limiting member is the coupling 7 and the coupling 7 is screwed to the liner 1, the moving range of the coupling 7 is small. The second limiting member 8 formed by the anchoring housing 81 and the anchoring ring 83 tightly clamps the liner 1 by the anchoring ring 83 being restricted by the inner wall surface of the anchoring housing 81 to realize the connection between the second limiting member 8 and the liner 1, so that the position of the second limiting member 8 can be adjusted arbitrarily according to the length of the expansion tube 2, and further the assembly of the expansion tube packer is simpler and more convenient.

[0048] Furthermore, in order to facilitate the bolt 82 to push the anchoring ring 83, the outer peripheral surface of the anchoring ring 83 is spindle-shaped, that is, the upper outer peripheral surface of the anchoring ring 83 is an expanded-diameter conical surface, and the lower outer peripheral surface of the anchoring ring 83 is a reduced-diameter conical surface, so that the bolt 82 can smoothly abut against the lower outer peripheral surface of the anchoring ring 83.

[0049] Of course, the structures of the first limiting member and the second limiting member 8 can also be interchanged, that is, the first limiting member is a structure including the anchoring housing 81 and the anchoring ring 83, the second limiting member 8 is the coupling 7, or both the first limiting member and the second limiting member 8 are couplings 7, or both the first limiting member and the second limiting member 8 are structures including the anchoring housing 81 and the anchoring ring 83.

[0050] In an embodiment of the present invention, the setting portion 31 is a stop ring with a central hole formed by the lower end surface of the axial channel contracting inward in the circumferential direction. The inner diameter of the stop ring is smaller than the diameter of the pressure-holding ball 32, and the pressure-holding ball 32 can be hermetically connected to the stop ring, thereby blocking the bottom end of the expansion tube packer.

[0051] In another embodiment of the present invention, the bottom of the axial channel is in the shape of a funnel with a wider upper part and a narrower lower part. The diameter of the bottom of the axial channel is smaller than the diameter of the pressure-holding ball 32. The setting part 31 is formed at the bottom of the axial channel. The pressure-holding ball 32 can be seated at the bottom of the axial channel under the guiding action of the axial channel, thereby blocking the bottom end of the expandable packer.

[0052] The following specifically describes the assembly process and the usage process of the expandable packer provided by the present invention with reference to the accompanying drawings:

[0053] As Figure 1 shown, the expandable tube 2 with tube fixing blocks 4 screwed at both ends is sleeved outside the liner 1. At the same time, the through holes 11 on the liner 1 are communicated with the expansion annulus 21. A first sealing ring 5 is arranged between the tube fixing block 4 and the liner 1, and a second sealing ring 6 is arranged between the expandable tube 2 and the tube fixing block 4 to ensure the sealing performance of the expansion annulus 21. Then, the coupling 7 is screwed onto the upper end of the liner 1, and the tube fixing block 4 at the upper end of the expandable tube 2 abuts against the bottom surface of the coupling 7. The anchoring outer shell 81 with an anchoring ring 83 inside is sleeved on the liner 1, and the top surface of the anchoring outer shell 81 abuts against the bottom surface of the tube fixing block 4 at the lower end of the expandable tube 2. Then, the bolt 82 is screwed into the threaded hole 813, so that the bolt 82 pushes the fixing ring to move towards the expandable tube 2 until the anchoring ring 83 contracts under the action of the inner wall surface of the accommodating cavity 812 and tightly clamps the liner 1. After that, the pressure-holding nipple 3 is connected to the lower end of the liner 1, and thus the assembly of the expandable packer is completed;

[0054] As Figure 4 shown, during use, the expandable packer is connected to the tubing 100 through the coupling 7 and is lowered into the well with the tubing 100. After the expandable packer is lowered to the isolation position, the pressure-holding ball 32 is dropped from the wellhead. The pressure-holding ball 32 enters the pressure-holding nipple 3 through the liner 1 and is hermetically connected to the setting part 31 formed at the bottom of the axial channel, so that the bottom of the expandable packer is blocked. Since the mud pump of the drilling rig continuously injects liquid into the pipe string, the expandable packer starts to hold pressure. The liquid in the liner 1 will flow into the expansion annulus 21 through the plurality of through holes 11. As the liquid is continuously injected, the pressure in the expansion annulus 21 continues to rise, and the expandable tube 2 starts to expand. When the pressure reaches the preset value, by controlling the mud pump of the drilling rig, the pressure in the expansion annulus 21 is not allowed to continue to increase, and the pressure in the expansion annulus 21 is maintained at the preset value for a period of time to ensure the successful isolation of the high-pressure formation 200. After that, by controlling the mud pump of the drilling rig, the expansion annulus 21 starts to release pressure, and the isolation of the entire formation 200 is completed.

[0055] In summary, for the expansion pipe packer provided by the present invention, by applying pressure to seat the pressure-holding nipple, liquid or gas can directly enter the expansion annulus, causing the pressure in the expansion annulus to continuously increase, and the expansion pipe starts to expand to seal off the formation. There is no need for an expansion cone or mechanical action, which is simple and convenient, and enables rapid formation sealing.

[0056] For the expansion pipe packer provided by the present invention, the expansion pipe is made of a metal pipe, so that the expansion pipe packer has the advantage of being able to resist high external pressure.

[0057] For the expansion pipe packer provided by the present invention, by providing a first limiting member and a second limiting member, the expansion pipe can be effectively prevented from moving during the lowering process or before expansion.

[0058] The above is only a schematic specific embodiment of the present invention and is not intended to limit the scope of the present invention. Any equivalent changes and modifications made by those skilled in the art without departing from the concept and principles of the present invention shall fall within the scope of protection of the present invention. Moreover, it should be noted that the components of the present invention are not limited to the above overall application. Each technical feature described in the specification of the present invention can be selected and used alone according to actual needs or combined with multiple features. Therefore, the present invention naturally covers other combinations and specific applications related to the inventive points of this case.

Claims

1. An expandable-tube packer, characterized in that, the expandable-tube packer comprises: a liner, on the wall of which there are through holes; an expandable tube, which is sleeved outside the liner and can move axially along the liner. The expandable tube is a metal tube. The two ends of the expandable tube are respectively sealed and connected to the liner, and an expansion annulus is formed between the expandable tube and the liner. The expansion annulus is communicated with the through holes; a limit assembly, which includes a first limit member and a second limit member sleeved on the liner, and both the first limit member and the second limit member can be disassembled and assembled to be connected to the liner. The two ends of the expandable tube can respectively abut against the first limit member and the second limit member; a pressure-holding nipple, which can be disassembled and assembled to be connected to the lower end of the liner. The pressure-holding nipple has an axial channel communicating with the liner, and a setting part for a pressure-holding ball to be set is arranged in the axial channel; both the pressure-holding nipple and the pressure-holding ball are made of drillable materials; the first limit member is a coupling. The coupling is provided with an internal thread, and the outer peripheral surface of the upper part of the liner is provided with an external thread. Through the screwing fit of the internal thread and the external thread, the coupling is connected to the liner; the liner can be connected to an oil pipe through the coupling; the second limit member includes: an anchoring housing, which is sleeved outside the liner. An accommodation cavity is arranged inside the anchoring housing. The inner wall surface of the accommodation cavity is an expanded-diameter conical surface. A threaded hole communicating with the accommodation cavity is opened at one end of the anchoring housing facing away from the expandable tube, and a bolt is screwed in the threaded hole; an anchoring ring, which is arranged in the accommodation cavity. The outer peripheral surface of the anchoring ring is a conical surface adapted to the inner wall surface of the accommodation cavity. Through the screwing fit of the bolt and the threaded hole, the bolt can push the anchoring ring to move, and the movement of the anchoring ring can clamp the liner; the setting part is a retaining ring with a central hole formed by the lower end surface of the axial channel shrinking inwards along the circumferential direction. The inner diameter of the retaining ring is smaller than the diameter of the pressure-holding ball; the bottom of the axial channel is in a funnel shape with a wider upper part and a narrower lower part. The bottom diameter of the axial channel is smaller than the diameter of the pressure-holding ball, and the setting part is formed at the bottom of the axial channel.

2. The expandable-tube packer according to claim 1, characterized in that, tube fixing blocks are respectively connected to the two ends of the expandable tube. The tube fixing blocks are sleeved outside the liner and can move axially along the liner, and a first sealing ring is arranged between the tube fixing blocks and the liner.

3. The expandable-tube packer according to claim 2, characterized in that, the expandable tube is connected to the tube fixing block by threads, and a second sealing ring is arranged between the tube fixing block and the expandable tube.

4. The expandable-tube packer according to any one of claims 1 to 3, characterized in that, a plurality of the through holes are radially opened on the wall of the liner.

5. The expandable-tube packer according to claim 4, characterized in that, the plurality of through holes are arranged at equal intervals.

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