Shaft bottom supercharging device and system for coal bed gas horizontal well anti-reflection

Abstract

The invention discloses a well bottom supercharging device and system for coal bed gas horizontal well anti-reflection. The device comprises a driving device, a locking mechanism, an opening and closing mechanism, a mounting cylinder and a shell, the shell can be connected with an oil pipe and a screen pipe. The locking mechanism comprises a gear, a rack and a clamping piece; the gear is connected with the driving device and meshed with the rack, the clamping piece is connected with the end of the rack, and the driving device can drive the gear to rotate so as to drive the rack and the clamping piece to reciprocate; the opening and closing mechanism comprises a telescopic rod, a plurality of groups of umbrella ribs and a sealing layer covering the umbrella ribs; the telescopic rod is connected with the clamping piece; a hollow net rack is arranged in the shell, and the two ends of the umbrella ribs are connected with the telescopic rod and the center of the net rack respectively; the clamping piece can drive the telescopic rod to stretch out and draw back, and when the telescopic rod stretches out, the umbrella ribs open the sealing layer to block the net frame. The device can generate high-pressure liquid with fluctuating pressure, the well wall is periodically impacted through the high-pressure liquid, shaft dredging is achieved, and the permeability of a near-well coal seam is improved.

Description

Technical Field

[0001] The present invention relates to the field of oil and gas production equipment, and in particular to a bottom hole pressurizing device and system for increasing the permeability of a coalbed methane horizontal well. Background Art

[0002] In recent years, as countries around the world continue to increase their development of unconventional energy, coalbed methane has attracted the attention of all countries. Coalbed methane resources are large and widely distributed, but due to its difficulty in mining, its development is relatively slow. Among them, the factors that restrict coalbed methane mining include low coal seam permeability, blockage of bottom well fracture channels, and coal powder accumulation.

[0003] At present, the domestic coalbed methane horizontal well development technology has become the mainstream. After a period of drainage and production, some horizontal wells become low-yield wells. The main reasons for the low production of horizontal wells are the accumulation of coal powder in the casing and the blockage of cracks around the casing. Summary of the invention

[0004] In order to enrich the product types of bottom hole boosting devices for coalbed methane horizontal wells, increase the selection space of bottom hole boosting methods for coalbed methane horizontal wells, and increase the permeability of coal seams, an embodiment of the present invention provides a bottom hole boosting device and system for increasing the permeability of coalbed methane horizontal wells.

[0005] In a first aspect, an embodiment of the present invention provides a bottom hole pressurizing device for increasing the permeability of a coalbed methane horizontal well, comprising a driving device, a locking mechanism, an opening and closing mechanism, a mounting tube and a housing;

[0006] The driving device and the locking mechanism are arranged in the installation tube; the installation tube and the opening and closing mechanism are arranged in the shell; the shell can be connected to the oil pipe and the screen pipe respectively;

[0007] The locking mechanism includes a gear, a rack and a clamping member; the gear is connected to the driving device and meshes with the rack, the clamping member is connected to the end of the rack, and the driving device can drive the gear to rotate, so as to drive the rack and the clamping member to reciprocate;

[0008] The installation cylinder is provided with a card interface, and the card connector can be inserted into the card interface;

[0009] The opening and closing mechanism comprises a telescopic rod, a plurality of umbrella ribs and a sealing layer covering the plurality of umbrella ribs; the telescopic rod is connected to the clamping member; a hollow grid is arranged in the shell, and the two ends of the umbrella ribs are respectively connected to the telescopic rod and the center of the grid;

[0010] The clamping member can drive the telescopic rod to extend and retract, and when the telescopic rod is in an extended state, the ribs open the sealing layer to seal the grid.

[0011] In one or some optional embodiments, the bottom hole pressure boosting device further comprises an impeller structure;

[0012] The impeller structure comprises a fixed shaft and an impeller sleeved on the fixed shaft, and the impeller can rotate relative to the fixed shaft under the impact force of the fluid;

[0013] The fixed shaft is fixed to a side of the grid away from the umbrella ribs.

[0014] In one or some optional embodiments, an oil pipe connection portion is provided at the inlet end of the housing, and the oil pipe connection portion is used to connect the oil pipe;

[0015] The outlet end of the shell is provided with a screen tube connecting portion, and the screen tube connecting portion is used to connect the screen tube.

[0016] In one or some optional embodiments, when the screen tube connecting portion is connected to the screen tube, the impeller structure is located inside the screen tube.

[0017] In one or some optional embodiments, the bottom hole pressurizing device further includes a pressure sensor and a controller;

[0018] The pressure sensor is arranged at one end of the mounting tube close to the oil pipe, and is used to monitor the pressure of the fluid flowing into the housing;

[0019] The controller is connected to the pressure sensor and the driving device respectively; the controller can obtain the pressure monitoring result of the pressure sensor and control the action of the driving device according to the pressure monitoring result.

[0020] In one or some optional embodiments, a diaphragm is provided at one end of the mounting tube close to the oil pipe, and the pressure sensor is in close contact with the diaphragm.

[0021] In one or some optional embodiments, the pressure sensor is a contact pressure sensor.

[0022] In one or some optional embodiments, the rib includes a first connecting rod and a second connecting rod that are hinged.

[0023] In one or some optional embodiments, the bottom hole pressurizing device further comprises a support structure;

[0024] The support structure can be arranged between the screen pipe and the guide shoe;

[0025] The support structure comprises a short tube, two latches, and a first support rod, an elastic member, and a second support rod connected in sequence;

[0026] The short tube can be longitudinally fixed to the guide shoe, the first support rod, the elastic member and the second support rod are arranged in the short tube, and the two latches are radially inserted in the short tube to lock the elastic member into a compressed state;

[0027] The two latches can release the locking of the elastic member under the impact force of the fluid, so that the first support rod and the second support rod extend out of the short tube and abut against the inner wall of the wellbore.

[0028] In a second aspect, an embodiment of the present invention provides a bottom hole pressurization system for increasing the permeability of a coalbed methane horizontal well, comprising the bottom hole pressurization device for increasing the permeability of a coalbed methane horizontal well described in the first aspect, an oil pipe and a screen pipe.

[0029] The beneficial effects of the above technical solution provided in the embodiments of the present invention include at least:

[0030] The bottom hole pressurizing device for increasing the permeability of coalbed methane horizontal wells provided in the embodiment of the present invention drives the locking mechanism to open or close the opening and closing mechanism through a driving device, so that intermittent pressure excitement is formed in the bottom hole pipe string, and a high-pressure liquid with fluctuating pressure is generated. The high-pressure liquid periodically impacts the well wall, effectively cleans the coal powder, realizes wellbore dredging, causes fatigue damage to the coal seam, opens the coal seam cracks, and improves the permeability of the near-well coal seam; by connecting the ribs to the grid and the telescopic rods respectively, an umbrella-shaped opening and closing structure is formed, which occupies a smaller space when the ribs are not opened, thereby avoiding obstruction of liquid passage; by arranging a sealing layer on the surface of the ribs, when the ribs are opened, the shell is sealed, and then the pressure in the pipe string is held down, which greatly increases the pressure and impact force of the liquid in the pipe string.

[0031] Other features and advantages of the present invention will be described in the following description, and partly become apparent from the description, or understood by practicing the present invention. The purpose and other advantages of the present invention can be realized and obtained by the structures particularly pointed out in the written description and the accompanying drawings.

[0032] The technical solution of the present invention is further described in detail below through the accompanying drawings and embodiments. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] The accompanying drawings are used to provide a further understanding of the present invention and constitute a part of the specification. Together with the embodiments of the present invention, they are used to explain the present invention and do not constitute a limitation of the present invention. In the accompanying drawings:

[0034] Figure 1 It is a schematic structural diagram of a bottom hole pressurizing device for increasing the permeability of a coalbed methane horizontal well provided in an embodiment of the present invention;

[0035] Figure 2It is a schematic structural diagram of a bottom hole pressurization system for increasing the permeability of a coalbed methane horizontal well provided in an embodiment of the present invention.

[0036] In the figure:

[0037] 1. Driving device;

[0038] 2. Locking mechanism; 21. Gear; 22. Rack; 23. Snap-on part;

[0039] 3. opening and closing mechanism; 31. telescopic rod; 32. ribs; 321. first connecting rod; 322. second connecting rod; 33. sealing layer;

[0040] 4. Install the cylinder; 41. Card interface;

[0041] 5. Shell; 51. Grid; 52. Oil pipe connection; 53. Screen pipe connection;

[0042] 6. Impeller structure; 61. Fixed shaft; 62. Impeller;

[0043] 7. Pressure sensor;

[0044] 8. Diaphragm;

[0045] 9. Support structure; 91. Short tube;

[0046] 10. Oil pipe; 101. Vertical oil pipe; 102. Horizontal oil pipe; 103. Steering oil pipe; 11. Screen tube; 12. Water storage tank; 13. Fracturing truck; 131. Liquid injection pipe; 14. Generator; 15. Derrick; 16. Hoist; 17. Hanger; 18. Flange; 19. Guide shoe;

[0047] 100. Bottom-hole pressure-boosting device. DETAILED DESCRIPTION

[0048] The exemplary embodiments of the present disclosure will be described in more detail below with reference to the accompanying drawings. Although the exemplary embodiments of the present disclosure are shown in the accompanying drawings, it should be understood that the present disclosure can be implemented in various forms and should not be limited by the embodiments set forth herein. On the contrary, these embodiments are provided to enable a more thorough understanding of the present disclosure and to fully convey the scope of the present disclosure to those skilled in the art.

[0049] In the description of the present invention, it should be noted that the terms "center", "up", "down", "left", "right", "vertical", "horizontal", "inside", "outside", "far", "near", "front", "back" and the like indicate positions or positional relationships based on the positions or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as limiting the present invention. In addition, the terms "first", "second", and "third" are used for descriptive purposes only and cannot be understood as indicating or implying relative importance.

[0050] In the description of the present invention, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0051] The inventors found that when coal powder aggregation and blockage of cracks around the casing cause a decrease in horizontal well production, conventional hydraulic flushing cannot achieve the effect of increasing permeability due to its low pressure, and there are problems such as incomplete flushing of coal powder inside the casing.

[0052] Based on this, the present invention provides a bottom hole pressurizing device and system for increasing the permeability of a coalbed methane horizontal well, which will be described in detail below through specific embodiments.

[0053] Embodiment 1

[0054] The embodiment of the present invention provides a bottom hole pressurizing device 100 for increasing the permeability of a coalbed methane horizontal well (hereinafter referred to as the bottom hole pressurizing device 100). Figure 1 and Figure 2 As shown, it includes a driving device 1, a locking mechanism 2, an opening and closing mechanism 3, a mounting cylinder 4 and a housing 5;

[0055] The driving device 1 and the locking mechanism 2 are arranged in the installation cylinder 4; the installation cylinder 4 and the opening and closing mechanism 3 are arranged in the housing 5; the housing 5 can be connected to the oil pipe 10 and the screen pipe 11 respectively;

[0056] The locking mechanism 2 includes a gear 21, a rack 22 and a clamping member 23; the gear 21 is connected to the driving device 1 and meshes with the rack 22, the clamping member 23 is connected to the end of the rack 22, and the driving device 1 can drive the gear 21 to rotate, thereby driving the rack 22 and the clamping member 23 to reciprocate;

[0057] The mounting tube 4 is provided with a card interface 41, and the card connector 23 can be inserted into the card interface 41;

[0058] The opening and closing mechanism 3 includes a telescopic rod 31, a plurality of umbrella ribs 32, and a sealing layer 33 covering the plurality of umbrella ribs 32; the telescopic rod 31 is connected to the clamping member 23; a hollow grid frame 51 is arranged in the housing 5, and the two ends of the umbrella ribs 32 are respectively connected to the telescopic rod 31 and the center of the grid frame 51;

[0059] The clamping member 23 can drive the telescopic rod 31 to extend and retract. When the telescopic rod 31 is extended, the ribs 32 open the sealing layer 33 to seal the grid 51 .

[0060] In the embodiment of the present invention, the bottom hole booster device 100 can be installed in the bottom hole pipe string of the coalbed methane horizontal well, and its shell 5 can be connected to the oil pipe 10 and the screen pipe 11 respectively. Specifically, the inlet end of the shell 5 is provided with an oil pipe 10 connection part 52, and the oil pipe 10 connection part 52 is used to connect the oil pipe 10; the outlet end of the shell 5 is provided with a screen pipe 11 connection part 53, and the screen pipe 11 connection part 53 is used to connect the screen pipe 11. The high-pressure liquid injected from the ground fracturing vehicle 13 enters the bottom hole booster device 100 through the oil pipe 10 and is further pressurized, then flows into the screen pipe 11 and impacts the coal seam around the screen pipe 11, which has the effect of increasing the permeability of the coal seam near the wellbore.

[0061] In the embodiment of the present invention, the driving device 1 can be an electric motor, provided with a rotating shaft (not shown in the figure), and the rotating shaft can rotate clockwise and counterclockwise respectively, the gear 21 is connected to the rotating shaft, and the gear 21 and the rack 22 together form a gear 21 rack 22 mechanism, through which the torque output by the driving device 1 can be converted into a linear reciprocating motion of the rack 22 to push the clamping member 23 to move. A power source (not shown in the figure) is also provided in the installation cylinder 4, and the power source is connected to the driving device 1 and can supply power to the driving device 1. Specifically, the power source can be a battery, and the battery capacity can be about 20,000 mAh.

[0062] In the embodiment of the present invention, the opening and closing mechanism 3 can be opened and closed in an umbrella shape under the push and pull action of the telescopic rod 31, thereby blocking or unblocking the grid 51, realizing intermittent pressure relief in the bottom pipe string, further increasing the pressure of the high-pressure liquid, strengthening the impact on the near-well coal seam, reducing coal powder aggregation, and improving the permeability of the near-well coal seam. The number of groups of umbrella ribs 32 can be reasonably set according to factors such as the inner diameter of the shell 5 and the flow rate of the high-pressure liquid, as long as it has sufficient support force and ensures that the high-pressure liquid can pass through the shell 5 smoothly, and no specific limitation is made here.

[0063] In a specific embodiment, referring to Figure 1As shown, the bottom hole pressure boosting device 100 also includes an impeller structure 6. The impeller structure 6 may include a fixed shaft 61 and an impeller 62 sleeved on the fixed shaft 61, wherein the fixed shaft 61 is fixed to a side of the grid 51 away from the rib 32 and is located at the center of the grid 51. When the high-pressure liquid is released after being pressed in the housing 5, the impeller 62 can rotate rapidly relative to the fixed shaft 61 under the impact force of the high-pressure liquid. Further, when the connection portion 53 of the screen pipe 11 is connected to the screen pipe 11, the impeller structure 6 is located in the screen pipe 11, and the high-speed rotation of the impeller 62 can increase the impact force of the high-pressure liquid on the screen pipe 11 in the radial direction, thereby enhancing the effect of increasing the permeability of the near-well coal seam and dredging the wellbore.

[0064] In a specific embodiment, referring to Figure 1 As shown, the bottom hole boosting device 100 also includes a pressure sensor 7. The pressure sensor 7 is arranged at one end of the mounting tube 4 close to the oil pipe 10, and is used to monitor the pressure of the high-pressure liquid flowing into the housing 5; specifically, a diaphragm 8 is arranged at one end of the mounting tube 4 close to the oil pipe 10, and the pressure sensor 7 is installed in the mounting tube 4 close to the diaphragm 8, and the pressure sensor 7 is a contact type pressure sensor 7. When the high-pressure liquid flows into the housing 5, it will impact the diaphragm 8, so that the pressure sensor 7 monitors the pressure on the diaphragm 8, and then obtains the pressure of the high-pressure liquid. By arranging the diaphragm 8 at the end opening of the mounting tube 4, it is possible to prevent the high-pressure fluid from directly impacting the pressure sensor 7 and other components in the mounting tube 4, avoid damage to the pressure sensor 7 and other components, and extend the service life of the bottom hole boosting device 100.

[0065] In a specific embodiment, the bottom hole boosting device 100 also includes a controller (not shown in the figure), which is respectively connected to the pressure sensor 7 and the driving device 1; the controller can obtain the pressure monitoring result of the pressure sensor 7 and control the action of the driving device 1 according to the pressure monitoring result. For example, the minimum pressure threshold of the high-pressure liquid is set to 20MPa, and the maximum pressure threshold is set to 50MPa. When the pressure sensor 7 detects that the pressure of the high-pressure liquid is lower than 20MPa, the controller controls the drive device 1 to drive the gear 21 to rotate counterclockwise, so that the rack 22 extends to push the telescopic rod 31 to extend and open the ribs 32, thereby opening the opening and closing mechanism 3 to block the grid 51 (the outlet end of the shell 5), so that the high-pressure liquid in the oil pipe 10 and the shell 5 is pressurized. When the pressure sensor 7 detects that the pressure of the high-pressure liquid reaches 50MPa, the controller controls the drive device 1 to drive the gear 21 to rotate clockwise, so that the rack 22 is retracted to pull the telescopic rod back and close the ribs 32, thereby closing the opening and closing mechanism 3 and releasing the blockage of the outlet end of the shell 5. The high-pressure liquid after further pressurization can impact the near-well coal seam, greatly improving the wellbore dredging efficiency and the permeability of the near-well coal seam.

[0066] In a specific embodiment, referring to Figure 1As shown, the umbrella rib 32 includes a hinged first link 321 and a second link 322, and the end of the first link 321 is hinged to the telescopic rod 31, and the end of the second link 322 is hinged to the center of the grid 51. The lengths of the first link 321 and the second link 322 can be reasonably set according to the inner diameter of the shell 5, and are not specifically limited here. The hinge mode between the first link 321 and the second link 322 and the first link 321 and the second link 322 and the outside can refer to the detailed records in the prior art, and are not repeated here.

[0067] In a specific embodiment, the diameter of the shell 5 can be larger than the outer diameters of the oil pipe 10 and the screen tube 11 to avoid the setting of the internal components of the shell 5 hindering the circulation of the high-pressure liquid. The specific diameter can be reasonably set according to actual needs and is not specifically limited here.

[0068] In a specific embodiment, referring to Figure 1 As shown, the bottom hole booster device 100 also includes a support structure 9 that can be arranged between the screen pipe 11 and the guide shoe 19. The support structure 9 includes a short tube 91, two latches (not shown in the figure), and a first support rod (not shown in the figure), an elastic member (not shown in the figure) and a second support rod (not shown in the figure) connected in sequence; the short tube 91 can be longitudinally fixed to the guide shoe 19, the first support rod, the elastic member and the second support rod are arranged in the short tube 91, and two radial through holes (not shown in the figure) are respectively opened in the middle of the short tube 91, and the two latches are radially inserted in the two radial through holes of the short tube 91 to lock the elastic member in a compressed state; when the high-pressure liquid flows out of the housing 5, the two latches can be rushed out of the short tube 91 by the impact force of the high-pressure liquid, thereby releasing the lock of the elastic member, so that the first support rod and the second support rod extend out of the short tube 91 and press against the inner wall of the wellbore under the elastic force of the elastic member, thereby preventing the end of the pipe string from swinging greatly in the wellbore under the impact force of the high-pressure fluid, and preventing the pipe string and the coal seam from being damaged.

[0069] In the embodiment of the present invention, the specific process of further pressurizing the high-pressure liquid at the bottom of the coalbed methane horizontal well using the bottom hole pressurizing device 100 may include:

[0070] Inject high-pressure liquid into the oil pipe 10 through a fracturing truck 13 on the ground;

[0071] The high-pressure liquid flows through the oil pipe 10 and the housing 5 of the bottom hole booster device 100, and impacts the near-well coal seam at the screen pipe 11 section. The high-pressure liquid passing through the housing 5 impacts the diaphragm 8, so that the pressure sensor 7 monitors the pressure of the high-pressure liquid.

[0072] When the monitored high-pressure liquid pressure is less than the minimum pressure threshold, the driving device 1 is controlled to drive the gear 21 to rotate counterclockwise, driving the rack 22 to extend in the direction of the screen tube 11, thereby pushing the clamping member 23 to move, so that the telescopic rod 31 extends to open the opening and closing mechanism 3. When the clamping member 23 is clamped into the clamping interface 41, the opening and closing mechanism 3 is fully opened, and the outlet of the housing 5 is completely blocked. At this point, the high-pressure liquid begins to be pressed;

[0073] When the monitored high-pressure liquid pressure reaches the maximum pressure threshold, it means that the pressure holding is completed, and the control driving device 1 rotates clockwise, driving the rack 22 to retract in the direction of the oil pipe 10, thereby pushing the clamping part 23 to move, so that the telescopic rod 31 closes the opening and closing mechanism 3. When the clamping part 23 escapes from the clamping interface 41 and resets to the origin, the opening and closing mechanism 3 is completely closed, and the outlet end of the shell 5 is completely unblocked to achieve pressure release. The pressurized high-pressure liquid flows out of the shell 5 and impacts the impeller 62. The impeller 62 rotates at a high speed so that the pressurized high-pressure liquid impacts the screen pipe 11 and the near-well coal seam.

[0074] When the high-pressure liquid after further pressurization impacts the screen pipe 11, the latch of the support structure 9 is released from the short pipe 91, and the first support rod and the second support rod pop out and abut against the inner wall of the wellbore to prevent the pipe string from swinging significantly;

[0075] When the high-pressure liquid pressure drops below the minimum pressure threshold again, the gear 21 is driven to rotate counterclockwise again, and the cycle is repeated in sequence to achieve intermittent pressure holding and pressure release, thereby dredging the wellbore and increasing the permeability of the near-well coal seam.

[0076] The bottom hole pressurizing device 100 for increasing the permeability of coalbed methane horizontal wells provided in the embodiment of the present invention drives the locking mechanism 2 to open or close the opening and closing mechanism 3 through the driving device 1, so that intermittent pressure excitement is formed in the bottom hole pipe string, and a high-pressure liquid with fluctuating pressure is generated. The high-pressure liquid periodically impacts the well wall, effectively cleans the coal powder, realizes the wellbore dredging, causes fatigue damage to the coal seam, opens the coal seam cracks, and improves the permeability of the near-well coal seam; by connecting the umbrella ribs 32 to the grid 51 and the telescopic rod 31 respectively, an umbrella-shaped opening and closing structure is formed, which occupies a smaller space when the umbrella ribs 32 are not opened, avoiding obstruction of liquid passage; by arranging a sealing layer 33 on the surface of the umbrella ribs 32, when the umbrella ribs 32 are opened, the shell 5 is sealed, and then the pressure in the pipe string is held down, which greatly increases the pressure and impact force of the liquid in the pipe string.

[0077] Embodiment 2

[0078] Based on the same inventive concept, the embodiment of the present invention also provides a bottom hole pressurization system for increasing the permeability of coalbed methane horizontal wells (hereinafter referred to as the bottom hole pressurization system), referring to Figure 2As shown, it includes the bottom hole pressurizing device 100 for increasing the permeability of coalbed methane horizontal wells, the oil pipe 10 and the screen pipe 11 described in the first embodiment; the bottom hole pressurizing device 100 is connected to the oil pipe 10 and the screen pipe 11 respectively.

[0079] In the embodiment of the present invention, refer to Figure 2 As shown, the bottom hole pressurizing system also includes a water storage tank 12 and a fracturing truck 13 arranged at the wellhead, the water storage tank 12 is connected to the fracturing truck 13, and the injection pipe 131 of the fracturing truck 13 is connected to the oil pipe 10 in the wellbore; the fracturing truck 13 can pressurize the liquid to obtain high-pressure liquid, and inject the high-pressure liquid into the oil pipe 10.

[0080] In the embodiment of the present invention, referring to Figure 2 As shown, the bottom hole pressurization system also includes a generator 14, a derrick 15 and a hoist 16 arranged at the wellhead, the derrick 15 is arranged just above the wellhead, the hoist 16 is installed on the derrick 15, and the generator 14 is located on the ground and connected to the hoist 16. The hoist 16 can lift the pipe string in the wellbore.

[0081] In the embodiment of the present invention, referring to Figure 2 As shown, the bottom hole boosting system also includes a hanger 17, a flange 18 and a guide shoe 19; the oil pipe 10 includes a vertical oil pipe 101 arranged in the vertical well section, a horizontal oil pipe 102 arranged in the horizontal well section and a steering oil pipe 103 arranged in the deflection well section; the hanger 17 is arranged between the vertical oil pipe 101 and the steering oil pipe 103, and is used to connect the vertical oil pipe 101 and the steering oil pipe 103; the flange 18 is arranged between the steering oil pipe 103 and the horizontal oil pipe 102, and is used to connect the steering oil pipe 103 and the horizontal oil pipe 102. The guide shoe 19 is arranged at the end of the whole pipe string, and has a guiding effect when the pipe string is lowered into the wellbore.

[0082] In the embodiment of the present invention, the specific process of using the bottom hole pressurization system to increase the permeability of a coalbed methane horizontal well may include:

[0083] The bottom hole pressure boosting device 100 described in the first embodiment is fixedly connected to the screen pipe 11 and the oil pipe 10 respectively;

[0084] The length of the horizontal well section and the length of the vertical well section are determined respectively, and the bottom hole pressure boosting device 100 is sent to the target horizontal well section at the bottom of the well through the oil pipe 10;

[0085] Start the fracturing truck 13 on the ground to pressurize the liquid in the water storage tank 12 to obtain high-pressure liquid;

[0086] Inject high-pressure liquid into the oil pipe 10, and intermittently hold the pressure and release the pressure through the bottom-hole pressure boosting device 100, so as to intermittently flush the coal powder blocked at the bottom of the well;

[0087] When a target well section is flushed, the oil pipe 10 is dragged or extended to a preset distance by the hoist 16 to continue flushing the next target well section. In addition, any target well section can be flushed multiple times. When the return fluid gradually becomes clear, the flushing of the target well section is stopped, and this process is repeated until the entire horizontal well section is impacted.

[0088] Obviously, various changes and modifications may be made to the present invention by those skilled in the art without departing from the spirit and scope of the present invention. The present disclosure is not limited to the precise structure described above and shown in the accompanying drawings, and various changes and modifications may be made without departing from the scope thereof. The scope of the present disclosure is limited only by the appended claims. Thus, if these changes and modifications of the present invention fall within the scope of the claims of the present invention and their equivalents, the present invention is also intended to include these changes and modifications.

Claims

1. A bottom hole pressurizing device for increasing the permeability of coalbed methane horizontal wells, characterized in that: It includes a driving device, a locking mechanism, an opening and closing mechanism, a mounting cylinder and a housing; The driving device and the locking mechanism are arranged in the installation tube; the installation tube and the opening and closing mechanism are arranged in the shell; the shell can be connected to the oil pipe and the screen pipe respectively; The locking mechanism includes a gear, a rack and a clamping member; the gear is connected to the driving device and meshes with the rack, the clamping member is connected to the end of the rack, and the driving device can drive the gear to rotate, so as to drive the rack and the clamping member to reciprocate; The installation cylinder is provided with a card interface, and the card connector can be inserted into the card interface; The opening and closing mechanism includes a telescopic rod, a plurality of umbrella ribs and a sealing layer covering the plurality of umbrella ribs; The telescopic rod is connected to the clamping member; a hollow grid is arranged in the shell, and the two ends of the ribs are respectively connected to the telescopic rod and the center of the grid; The clamping member can drive the telescopic rod to extend and retract, and when the telescopic rod is in an extended state, the ribs open the sealing layer to seal the grid.

2. The bottom hole pressurizing device for increasing the permeability of coalbed methane horizontal wells according to claim 1 is characterized in that: The bottom hole pressure boosting device also includes an impeller structure; The impeller structure comprises a fixed shaft and an impeller sleeved on the fixed shaft, and the impeller can rotate relative to the fixed shaft under the impact force of the fluid; The fixed shaft is fixed to a side of the grid away from the umbrella ribs.

3. The bottom hole pressurizing device for increasing the permeability of coalbed methane horizontal wells according to claim 2 is characterized in that: The inlet end of the housing is provided with an oil pipe connecting portion, and the oil pipe connecting portion is used to connect the oil pipe; The outlet end of the shell is provided with a screen tube connecting portion, and the screen tube connecting portion is used to connect the screen tube.

4. The bottom hole pressurizing device for increasing the permeability of coalbed methane horizontal wells according to claim 3 is characterized in that: When the sieve tube connecting portion is connected to the sieve tube, the impeller structure is located in the sieve tube.

5. The bottom hole pressurizing device for increasing the permeability of coalbed methane horizontal wells according to claim 1 is characterized in that: The bottom hole pressurizing device also includes a pressure sensor and a controller; The pressure sensor is arranged at one end of the mounting tube close to the oil pipe, and is used to monitor the pressure of the fluid flowing into the housing; The controller is respectively connected to the pressure sensor and the driving device; The controller can obtain the pressure monitoring result of the pressure sensor and control the action of the driving device according to the pressure monitoring result.

6. The bottom hole pressurizing device for increasing the permeability of coalbed methane horizontal wells according to claim 5 is characterized in that: A diaphragm is disposed at one end of the mounting tube close to the oil pipe, and the pressure sensor is in close contact with the diaphragm.

7. The bottom hole pressurizing device for increasing the permeability of coalbed methane horizontal wells according to claim 5 is characterized in that: The pressure sensor is a contact type pressure sensor.

8. The bottom hole pressurizing device for increasing the permeability of coalbed methane horizontal wells according to claim 1 is characterized in that: The umbrella rib comprises a first connecting rod and a second connecting rod which are hinged.

9. The bottom hole pressurizing device for increasing the permeability of coalbed methane horizontal wells according to claim 1, characterized in that: The bottom hole pressurizing device also includes a support structure; The support structure can be arranged between the screen pipe and the guide shoe; The support structure comprises a short tube, two latches, and a first support rod, an elastic member, and a second support rod connected in sequence; The short tube can be longitudinally fixed to the guide shoe, the first support rod, the elastic member and the second support rod are arranged in the short tube, and the two latches are radially inserted in the short tube to lock the elastic member into a compressed state; The two latches can release the locking of the elastic member under the impact force of the fluid, so that the first support rod and the second support rod extend out of the short tube and abut against the inner wall of the wellbore.

10. A bottom hole pressurization system for increasing the permeability of coalbed methane horizontal wells, characterized in that: It comprises the bottom hole pressurizing device for increasing the permeability of coalbed methane horizontal wells, oil pipes and screen pipes as described in any one of claims 1 to 9.

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