Self-closed coal mine underground hydraulic fracturing packer

Abstract

The invention belongs to the technical field of hydraulic fracturing, and discloses a self-closed coal mine underground hydraulic fracturing packer which comprises an upper connector, one end of the upper connector is connected with a rubber sleeve assembly, the rubber sleeve assembly comprises a shell, one end of the shell is connected with the upper connector, the other end of the shell is connected with an expansion part, and the expansion part is connected with a rubber sleeve. The end, away from the shell, of the expansion part is connected with a floating head, a center pipe is arranged in the floating head in a penetrating mode, one end of the center pipe is connected with the rubber sleeve assembly, and through mutual cooperation between a detection block and a movable block, it is ensured that protrusions on a moving path are broken when the packer moves; it is ensured that the expansion part is not damaged by the protrusions in the moving process, the service life of the expansion part is ensured, when the expansion part is close to the target area, the position of the expansion part can be finely adjusted through contact between the detection block and the wall body, and the working accuracy of the expansion part is improved.

Description

Technical Field

[0001] The invention belongs to the technical field of hydraulic fracturing, in particular to a self-sealing underground coal mine hydraulic fracturing packer. Background Art

[0002] The drag packer in coal mines is suspended and fixed, hydraulically set, and unsealed by pressure relief. The steel skeleton rubber cylinder expands outward to seal the annular space of the open hole in the coal mine. From the setting and unsealing methods of the drag packer in coal mines, no mechanical movement is required during the working process, and it has advantages in operating in horizontal wells and inclined wells. It is applied to construction processes such as drag hydraulic fracturing of directional holes in coal mines.

[0003] The patent with application number CN202010787155.X discloses a packer, which includes: a center tube; an opening is provided on it; a piston cylinder, which is movably sleeved on the outside of the center tube; a plurality of rubber cylinders, which are sleeved on the piston cylinder; a locking sleeve, which is sleeved on the outside of the center tube; and the locking sleeve extends into the piston cylinder and forms a liquid inlet chamber connected to the opening with the piston cylinder, and the piston cylinder can move relative to the center tube under the action of the liquid in the liquid inlet chamber, thereby compressing the rubber cylinder; a locking piece, which is arranged on the piston cylinder; a stopper, which is arranged on the locking sleeve, and the stopper is used to limit the movement of the locking piece away from the rubber cylinder after the piston cylinder compresses the rubber cylinder; the above scheme provides a packer, which is simple to operate, reliable in setting, simple in structure and low in processing cost, but at the same time, during use, due to the irregular shape of the holes on the moving path, it is extremely easy for protruding stones to damage the expansion area, affecting the use of the device.

[0004] After the packer completes its sealing function, it needs to be pulled out of the wellbore. However, due to various reasons such as corrosion, scaling, and sand deposition underground, the packer is difficult to unseal and the pipe string cannot be pulled out, affecting the production of the coal mine and the subsequent replacement of the pipe string and other production problems.

[0005] Therefore, in view of the above technical problems, the present invention proposes a self-sealing underground coal mine hydraulic fracturing packer. Summary of the invention

[0006] The purpose of the present invention is to solve the above problems. The present invention provides a self-enclosed underground coal mine hydraulic fracturing packer, which has the advantages of ensuring the accuracy of the use of the fracturing packer and improving the service life of the rubber cartridge assembly.

[0007] To achieve the above-mentioned purpose, the present invention provides the following technical solutions: a self-enclosed underground coal mine hydraulic fracturing packer, comprising an upper joint, one end of the upper joint is connected to a rubber cartridge assembly, the rubber cartridge assembly comprises a shell, one end of the shell is connected to the upper joint, and the other end is connected to an expansion part, the end of the expansion part away from the shell is connected to a floating head, a center tube passes through the floating head, one end of the center tube is connected to the rubber cartridge assembly, and the end of the center tube away from the rubber cartridge assembly is connected to a lower joint.

[0008] Preferably, a movable cavity is opened in the shell, a movable ball is rotatably arranged in the movable cavity, and the movable cavity is connected with the central tube.

[0009] Preferably, the floating head comprises a connecting portion, a rotating roller is rotatably provided on the outer circumference of the connecting portion, and the connecting portion can slide along the radial direction of the central tube.

[0010] Preferably, the cross-sectional shape of the connecting portion along the radial direction of the central tube is an “I” shape, and the rotating roller is rotatably connected to a vertical region of the connecting portion.

[0011] Preferably, four detection blocks are connected to one end of the connection portion close to the lower joint, four movable blocks are distributed in an array on the circumference of the rotating roller, and the four movable blocks are movably connected to the rotating roller.

[0012] Preferably, the diameter of the movable block is larger than the diameter of the connecting portion, and the diameter of the expansion portion in an unexpanded state is smaller than the diameter of the floating head.

[0013] Preferably, a telescopic rod is connected between the movable block and the rotating roller.

[0014] Preferably, the state of the expansion portion can be controlled by the floating head.

[0015] Compared with the prior art, the present invention has the following beneficial effects:

[0016] 1. Through the cooperation between the detection block and the movable block, it is ensured that the packer breaks the protrusions on the moving path when moving, ensures that the expansion part will not be damaged by the protrusions during the movement, ensures the service life of the expansion part, and when the expansion part is close to the target area, the position of the expansion part can be fine-tuned by using the contact between the detection block and the wall, thereby improving the working accuracy of the expansion part.

[0017] 2. By cooperating with each other through the provided floating head, the detection block and the movable block, when the packer is taken out after completing the work, the cooperation between the floating head and the detection block is utilized to remove the piled objects on the upper side of the expansion part 202, thereby reducing the situation where the packer is stuck and cannot be removed, and after the movable block passes through the sealing area of ​​the expansion part, the reciprocating movement of the movable block is used to clear the piled objects on the moving path, thereby ensuring the patency of the moving path. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 It is a schematic diagram of the three-dimensional structure of the overall device of the present invention;

[0019] Figure 2 It is a schematic cross-sectional structure diagram of the overall device of the present invention;

[0020] Figure 3 It is a schematic diagram of the three-dimensional structure of the floating head of the present invention;

[0021] Figure 4 It is a schematic diagram of the cross-sectional structure of the floating head of the present invention;

[0022] Figure 5 It is a schematic diagram of the connection structure of the telescopic rod of the present invention.

[0023] Description of the drawings: 1. Upper joint; 2. Rubber cylinder assembly; 201. Shell; 2011. Active cavity; 2012. Active ball; 202. Expansion part; 3. Floating head; 301. Connecting part; 302. Detection block; 303. Rotating roller; 304. Active block; 3041. Telescopic rod; 4. Center tube; 5. Lower joint. DETAILED DESCRIPTION

[0024] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. 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.

[0025] like Figure 1-Figure 5As shown, a self-sealing coal mine underground hydraulic fracturing packer comprises an upper joint 1, one end of which is connected with a rubber cartridge assembly 2, wherein the expansion of the rubber cartridge assembly 2 is utilized to achieve plugging of the coal mine underground, wherein the rubber cartridge assembly 2 comprises a shell 201, one end of the shell 201 is connected with the upper joint 1, and the other end is connected with an expansion portion 202, an end of the expansion portion 202 away from the shell 201 is connected with a floating head 3, a central tube 4 is penetrated inside the floating head 3, and the central tube 4 is utilized to achieve the circulation of the liquid in the tube, one end of the central tube 4 is connected with the rubber cartridge assembly 2, and an end of the central tube 4 away from the rubber cartridge assembly 2 is connected with a lower joint 5, wherein the upper joint 1 and the lower joint 5 are connected to other objects to ensure the normal use of the fracturing packer. At the same time, in this solution, the expansion state of the expansion part 202 is controlled by the flow of liquid inside the rubber cartridge assembly 2, and the expansion state of the expansion part 202 can be regulated by the state of the floating head 3, that is, when the fracturing separator moves, the expansion part 202 is in an unexpanded state, which is convenient for moving the device to the target area. During the movement, the floating head 3 is used to ensure the safety of the rubber cartridge assembly 2 during the movement. At the same time, after the rubber cartridge assembly 2 moves to the target area, the flow of the liquid inside the rubber cartridge assembly 2 is used to cause the expansion part 202 to expand, thereby realizing the working requirements of the packer.

[0026] In order to ensure that the expansion part 202 in the rubber cylinder assembly 2 can expand normally, further, an active chamber 2011 for liquid circulation is opened in the shell 201, and an active ball 2012 is rotatably provided in the active chamber 2011. The spherical diameter of the active ball 2012 is smaller than the diameter of the active chamber 2011, and an abutment portion is provided at one end of the active chamber 2011 close to the floating head 3, wherein the abutment portion can clamp the position of the active ball 2012, and the active chamber 2011 is connected with the central tube 4. When the liquid flows in the active chamber 2011, the active ball 2012 can move in the active chamber 2011. At the same time, when the active ball 2012 moves to the end of the active chamber 2011, it abuts against the abutment portion in the active chamber 2011, thereby realizing the unilateral sealing of the active chamber 2011, limiting the circulation of the liquid in the active chamber 2011, and at the same time interrupting the connection between the active chamber 2011 and the central tube 4, to ensure that the expansion part 202 maintains the expanded state.

[0027] In order to ensure that the expansion part 202 will not be damaged by external stone walls during movement, and to ensure the accuracy of the expansion part when the expansion part 202 expands, the floating head 3 further includes a connecting part 301 for component support, and the connecting part 301 is sleeved on the central pipe 4. A rotating roller 303 is rotatably provided on the outer periphery of the connecting part 301, wherein the rotating roller 303 is made of a cemented carbide material, and the connecting part 301 can slide along the radial direction of the central pipe 4. When the packer is moving, the floating head 3 and the central pipe 4 maintain a stationary state unchanged, ensuring that the floating head 3 can break and eliminate the protrusions on the moving path during the movement.

[0028] It should be noted that during the movement of the connecting portion 301, the rotating roller 303 and the connecting portion 301 are in a state of relative rotation. When the packer moves to the target area, the rotating roller 303 and the connecting portion 301 remain relatively still to ensure the stable position of the packer.

[0029] In order to ensure the normal operation of the packer, further, the cross-sectional shape of the connecting part 301 along the radial direction of the central tube 4 is an "I" shape, and the rotating roller 303 is rotatably connected to the vertical area of ​​the connecting part 301, that is, the "1" area of ​​the "I" shape, and when the rotating roller 303 rotates on the connecting part 301, it conflicts with the wall of the shuttle area so that the rotating roller 303 cannot rotate, and at this time, the rotating roller 303 will be prompted to enter a protective state, that is, the structure of the rotating roller 303 is divided into two layers in the present scheme, wherein the side close to the central area of ​​the connecting part 301 is a power layer, and the side away from the central area of ​​the connecting part 301 is a working layer, wherein the power layer and the working layer are connected with mutually meshing teeth, and when the working layer conflicts with the outside and cannot move, relative displacement will occur between the teeth, and a pressure spring is connected between the power layer and the working layer.

[0030] It should be noted that when the rotating roller 303 is in a normal rotating state, the power layer and the working layer can maintain synchronous rotation through the mutually meshing teeth and the pressure spring.

[0031] During the movement of the connecting part 301, the rotating roller 303 rotates relative to the connecting part 301, and when the rotating roller 303 and the external protrusion come into contact with each other, the power layer maintains its rotation state unchanged, and the working layer and the external protrusion are in a relatively static state, thereby driving the mutually meshing teeth to move relative to each other, causing the pressure spring to compress, and increasing the contact pressure between the working layer and the external protrusion. When the material of the external protrusion is easy to break, as the pressure between the working layer and the external protrusion increases, the external protrusion will be broken and lose the contact with the working layer, ensuring that the rotating roller 303 is in a normal working state. When the material of the external protrusion is difficult to break through the rotational force of the working layer, the packer is controlled to move up and down, causing the working layer to separate from the conflicting object, and the position is adjusted to eliminate the protrusion.

[0032] In order to improve the detection of the packer's moving path and ensure the safety of the expansion part 202 during movement and use, further, four detection blocks 302 for identifying the external moving area are connected to one end of the connection part 301 close to the lower joint 5, wherein the detection blocks 302 are distributed in a circular array on the edge of one end of the moving direction of the connection part 301, and at the same time, a rotating shaft is provided to connect the detection block 302 and the connection part 301, and a torsion spring is sleeved on the rotating shaft, and four movable blocks 304 are distributed in an array on the circumference of the rotating roller 303, and the four movable blocks 304 are movably connected to the working layer of the rotating roller 303, wherein the detection block 302 and the movable block 304 are both made of cemented carbide.

[0033] The detection block 302 is rotationally connected to the connection part 301, and during the use of the detection block 302, the rotational connection between the detection block 302 and the connection part 301 is divided into active rotation and passive rotation. When the connection part 301 is moving, when the detection block 302 conflicts with the protrusion on the moving path, as the connection part 301 continues to move, the detection block 302 and the connection part 301 are prompted to rotate, and at the same time, the contact pressure between the detection block 302 and the protrusion is increased to break the protrusion and reduce the danger of subsequent movement of the expansion part 202. At the same time, when the packer moves to the target area, the detection block 302 is driven to actively rotate relative to the connection part 301, so that the detection block 302 conflicts with the wall on the moving path to avoid the position of the packer. If necessary, the height of the packer can be fine-tuned by adjusting the angle between the detection block 302 and the wall.

[0034] At the same time, the movable block 304 is used to rotate synchronously with the rotating roller 303, so that the movable block 304 performs a secondary inspection on the area passed by the detection block 302, ensuring that the expansion part 202 of the sealer will not be damaged by external protrusions during the movement, and the movement of the movable block 304 is used to clean the inner wall after the detection block 302 is broken, ensuring the safety of the moving path.

[0035] During the operation of the movable block 304, the working radius of the movable block 304 is regulated by controlling the movement of the movable block 304 on the rotating roller 303, ensuring that the movable block 304 can perform secondary inspection and cleaning on the area passed by the detection block 302, and after the packer moves to the target area, the movable block 304 is controlled to contact the inner wall on the moving path to ensure that the position of the packer is constrained when the expansion part 202 is unfolded.

[0036] In order to ensure that no abnormal protrusions will appear in the area passed by the connecting part 301 and the movable block 304 to cause damage to the expansion part 202, further, the diameter of the movable block 304 is larger than the diameter of the connecting part 301, and the diameter of the expansion part 202 in the unexpanded state is smaller than the diameter of the floating head 3, ensuring that during the movement of the packer, the wall of the moving path will not cause damage to the expansion part 202, thereby improving the service life of the expansion part 202.

[0037] In order to improve the control over the movable block 304 and ensure that the movable block 304 can quickly work according to the detection block 302, further, a telescopic rod 3041 is connected between the movable block 304 and the rotating roller 303, wherein the telescopic rod 3041 is connected to the working layer on the rotating roller 303, so that the telescopic length of the telescopic rod 3041 can be adjusted according to the use requirements of the movable block 304 to ensure the normal operation of the movable block 304.

[0038] In order to ensure the safety of the expansion part 202 during use and further ensure the service life of the expansion part 202, the state of the expansion part 202 can be controlled by the floating head 3. When the floating head 3 conflicts with the inner wall on the moving path, the expansion part 202 can expand normally. After completing the work requirements, when the packer needs to be moved out of the target area, the work of the floating head 3 can ensure the removal rate of the packer.

[0039] During operation, first ensure that the upper joint 1 and the lower joint 5 are connected to external objects respectively, and then move the packer into the target hole, so that the rubber cartridge assembly 2 can be moved to the target area and then deployed.

[0040] Meanwhile, during the movement, the floating head 3 first enters the target hole, and identifies the inner wall state on the moving path during the movement, ensuring that the expansion part 202 will not be damaged by external protrusions during the movement, thereby improving the service life of the expansion part 202.

[0041] When the connecting part 301 is moving, the detection block 302 is passively rotated, and then when the detection block 302 collides with the protrusion on the moving path, the continuous movement of the connecting part 301 causes the detection block 302 and the connecting part 301 to rotate, and at the same time, the contact pressure between the detection block 302 and the protrusion is increased, thereby breaking the protrusion and reducing the danger of the subsequent movement of the expansion part 202.

[0042] During the movement of the connecting part 301, the rotating roller 303 rotates relative to the connecting part 301, thereby driving the movable block 304 to rotate. When the rotating roller 303 or the movable block 304 contacts with the external protrusion, the power layer maintains the rotation state unchanged, and the working layer is in a relatively static state with the external protrusion due to the influence of the resistance force, driving the mutually meshing teeth to move relative to each other, causing the pressure spring to compress, and increasing the resistance pressure between the working layer and the external protrusion. When the material of the external protrusion is easy to break, as the pressure between the working layer and the external protrusion increases, the external protrusion will be broken and lose the resistance to the working layer, ensuring that the rotating roller 303 is in a normal working state. When the material of the external protrusion is difficult to break through the rotation force of the working layer, the packer is controlled to move up and down, causing the working layer to separate from the resistance, adjusting the position and then eliminating the contact with the protrusion, thereby ensuring the stability of the expansion part 202 on the moving path, and ensuring that the sealing of the expansion part 202 will not be affected by external factors during the movement.

[0043] And when the movable block 304 rotates synchronously with the rotating roller 303, the movable block 304 is prompted to perform a secondary inspection on the area passed by the detection block 302 to ensure that the expansion part 202 of the sealer will not be damaged by external protrusions during the movement, and the movement of the movable block 304 is used to clean the inner wall after the detection block 302 is broken, ensuring the safety of the moving path.

[0044] At the same time, when the packer moves to the target area, the detection block 302 is driven to actively rotate relative to the connecting portion 301, so that the detection block 302 contacts the wall on the moving path to prevent the packer from moving.

[0045] When the seal is moved, there will be an error between the working area of ​​the expansion part 202 and the area that needs to be closed, and then the height of the seal can be fine-tuned by adjusting the angle between the detection block 302 and the wall. That is, after the expansion part 202 moves to the target area and the detection block 302 contacts the external wall, the angle between the control detection block 302 and the connecting part 301 is deflected, thereby driving the position of the expansion part 202 to be fine-tuned to ensure that the working area of ​​the expansion part 202 is accurate.

[0046] During the operation of the movable block 304, the working radius of the movable block 304 is regulated by controlling the movement of the movable block 304 on the rotating roller 303, ensuring that the movable block 304 can perform secondary inspection and cleaning on the area passed by the detection block 302, and after the packer moves to the target area, the movable block 304 is controlled to contact the inner wall on the moving path to ensure that the position of the packer is constrained when the expansion part 202 is deployed, ensuring the accuracy of the isolation position of the expansion part 202.

[0047] After the packer completes the isolation of the target area, the expansion part 202 is controlled to shrink and the packer is moved out of the target area. However, during the isolation process, gravel will accumulate, affecting the removal of the packer. At this time, the floating head 3 is controlled to move up and down along the central tube 4 to cause the gravel to fall along the edge of the packer. If necessary, after the floating head 3 shrinks, the detection block 302 is caused to contact the inner wall, and the floating head 3 is controlled to extend to prevent the packer from being stuck by the gravel, thereby improving the recovery efficiency of the packer. After the movable block 304 passes through the sealing area of ​​the expansion part 202, the movable block 304 is controlled to move back and forth through the telescopic rod 3041 to remove the gravel and piled objects, thereby ensuring the normal movement path.

[0048] It should be noted that, in this article, the terms "comprises", "includes" or any other variations thereof are intended to cover non-exclusive inclusion, so that a process, method, article or apparatus that includes a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or apparatus.

[0049] Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A self-sealing coal mine underground hydraulic fracturing packer, comprising an upper joint (1), characterized in that: One end of the upper joint (1) is connected to a rubber cartridge assembly (2), and the rubber cartridge assembly (2) comprises a shell (201), one end of the shell (201) is connected to the upper joint (1), and the other end is connected to an expansion portion (202), an end of the expansion portion (202) away from the shell (201) is connected to a floating head (3), a center tube (4) passes through the inside of the floating head (3), one end of the center tube (4) is connected to the rubber cartridge assembly (2), and an end of the center tube (4) away from the rubber cartridge assembly (2) is connected to a lower joint (5).

2. The self-enclosed underground coal mine hydraulic fracturing packer according to claim 1, characterized in that: An active cavity (2011) is provided in the shell (201), an active ball (2012) is rotatably provided in the active cavity (2011), and the active cavity (2011) is connected to the central tube (4).

3. The self-enclosed underground coal mine hydraulic fracturing packer according to claim 1, characterized in that: The floating head (3) comprises a connecting portion (301), a rotating roller (303) is rotatably provided on the outer periphery of the connecting portion (301), and the connecting portion (301) can slide along the radial direction of the central tube (4).

4. The self-enclosed underground coal mine hydraulic fracturing packer according to claim 3 is characterized in that: The cross-sectional shape of the connecting portion (301) along the radial direction of the central tube (4) is an "I" shape, and the rotating roller (303) is rotatably connected to the vertical area of ​​the connecting portion (301).

5. The self-enclosed underground coal mine hydraulic fracturing packer according to claim 4 is characterized in that: Four detection blocks (302) are connected to one end of the connection portion (301) close to the lower joint (5), and four movable blocks (304) are distributed in an array on the circumference of the rotating roller (303), and the four movable blocks (304) are movably connected to the rotating roller (303).

6. The self-enclosed underground coal mine hydraulic fracturing packer according to claim 5 is characterized in that: The diameter of the movable block (304) is larger than the diameter of the connecting portion (301), and the diameter of the expansion portion (202) in an unexpanded state is smaller than the diameter of the floating head (3).

7. The self-enclosed underground coal mine hydraulic fracturing packer according to claim 5, characterized in that: A telescopic rod (3041) is connected between the movable block (304) and the rotating roller (303).

8. The self-enclosed underground coal mine hydraulic fracturing packer according to claim 1, characterized in that: The state of the expansion portion (202) can be controlled by the floating head (3).

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