Underground milling device

Abstract

The invention relates to the field of oil production engineering, and discloses an underground milling device. The underground milling device comprises a pipe body, a sedimentation assembly, a pumping assembly, a mounting seat and an axial driving assembly, wherein the pipe body comprises a pipe column and a central pipe; the sedimentation assembly is arranged at the first end of the central pipe; the pumping assembly is arranged at the end, away from the pipe body, of the sedimentation assembly. The mounting seat is arranged at the second end of the central pipe; an output shaft is arranged at one end of the mounting seat; the axial driving assembly is arranged on the pipe body. According to the underground grinding and milling device, bit pressure can be provided for the grinding and milling assembly through the axial driving assembly, the grinding and milling effect of the grinding and milling assembly is ensured, power is provided for fluid through the pumping assembly, the fluid carries chips to flow out through the pipe body from bottom to top, the chips carried by the fluid are collected through the sedimentation assembly, and the efficiency is improved. The problem that a stratum is seriously polluted when milling construction is carried out in a large-leakage well in a traditional chip carrying mode is effectively solved, meanwhile, the situation that a pipe column is clamped due to chip sedimentation is avoided, and smooth construction is guaranteed.

Description

Technical Field

[0001] The present invention relates to the field of oil production engineering, and particularly to a downhole milling device. Background Art

[0002] Milling operation is an important process for dealing with fish heads in the oilfield production process. Usually, rotary tables, power swivels, positive displacement motors, etc. are mainly used to provide rotational power for milling operation, and the operation is carried out by ground power or liquid propulsion. At the same time, a complete circulation channel needs to be formed to carry the debris formed by milling out of the wellbore. However, with the further development of the oilfield, the downhole conditions are becoming increasingly complex, and the formation leakage is serious. In some wells, an effective circulation channel cannot even be formed, resulting in less fluid return or even no fluid return, so that the debris cannot be carried out of the wellbore, causing quality accidents such as stuck pipe or blocked tubing. To this end, mud, plugging agents, etc. are usually used to carry debris, but this kind of debris-carrying method causes greater pollution to the formation. In addition, in the milling operation of highly deviated wells, due to the pipe string lying on the bottom, it is impossible to effectively pressurize the milling surface, and it is difficult to ensure the milling effect. Moreover, the debris generated during the milling process is extremely easy to settle in the horizontal section, causing the occurrence of pipe string sticking, resulting in problems such as pipe string fracture and equipment shutdown, and it is necessary to frequently trip the tools, which further leads to problems such as high construction cost, high construction risk, long construction period, and high labor intensity of workers. Summary of the Invention

[0003] In order to solve the above technical problems or at least partially solve the above technical problems, the present invention provides a downhole milling device.

[0004] The present invention provides a downhole milling device, comprising:

[0005] A pipe body, comprising a pipe string and a central pipe inserted through one end of the pipe string, the central pipe having a first end extending into the interior of the pipe string and a second end extending out of the pipe string;

[0006] A sedimentation assembly, disposed at the first end of the central pipe, the sedimentation assembly being configured to filter and collect debris entrained in the fluid passing through the sedimentation assembly;

[0007] A pump suction assembly, disposed at one end of the sedimentation assembly away from the pipe body, for providing a force to the fluid in the direction from the second end of the central pipe towards the first end of the central pipe;

[0008] A mounting seat, disposed at the second end of the central pipe, an output shaft for mounting a milling assembly being provided at one end of the mounting seat away from the pipe body, and the central pipe being capable of driving the output shaft to rotate;

[0009] An axial driving assembly, disposed on the pipe body, for driving the mounting seat to move along the axial direction of the pipe body.

[0010] Optionally, the downhole milling device further includes an anchoring assembly disposed inside the pipe string, and the anchoring assembly is configured to extend out of the pipe string to anchor to the casing or retract into the interior of the pipe string.

[0011] Optionally, a first hydraulic chamber is formed between the pipe string and the central pipe. A hydraulic assembly for injecting or discharging a force-transmitting medium into or from the first hydraulic chamber is provided inside the pipe string. The anchoring assembly is inserted through the peripheral wall of the pipe string, and the anchoring assembly is configured as follows:

[0012] When a force-transmitting medium with a first preset pressure is injected into the first hydraulic chamber, it extends out of the pipe string;

[0013] When the pressure of the force-transmitting medium in the first hydraulic chamber is lower than the first preset pressure, the anchoring assembly retracts into the pipe string.

[0014] Optionally, an anchoring hole communicating with the first hydraulic chamber is provided on the peripheral wall of the pipe string. The anchoring assembly includes:

[0015] An anchor claw disposed in the anchoring hole, and the anchor claw is sealingly connected to the inner wall of the anchoring hole;

[0016] A reset member for providing a force acting in the direction of the first hydraulic chamber to the anchor claw.

[0017] Optionally, a cover plate is provided at one end of the anchoring hole away from the first hydraulic chamber. The reset member includes a reset spring disposed between the cover plate and the anchor claw, and an avoidance hole through which the anchoring end of the anchor claw can extend is provided on the cover plate.

[0018] Optionally, an input shaft is sleeved on the outer periphery of the second end of the central pipe. The central pipe is used to drive the input shaft to rotate, and the input shaft can move relative to the central pipe along the axial direction of the central pipe. A speed-changing assembly is provided inside the mounting seat, and the input shaft drives the output shaft to rotate through the speed-changing assembly.

[0019] Optionally, a guiding protrusion is provided on the outer periphery of the central pipe, and the guiding protrusion extends along the axial direction of the central pipe. A guiding groove matching the guiding protrusion is provided on the inner wall of the input shaft.

[0020] Optionally, the axial driving assembly includes a thrust piston sleeved on the outer periphery of the input shaft. The input shaft and the thrust piston can rotate relative to each other. One end of the thrust piston extending into the pipe string is used to seal the end of the first hydraulic chamber, and the end of the thrust piston extending out of the pipe string is connected to the mounting seat. The thrust piston is arranged such that when a force-transmitting medium with a second preset pressure is injected into the first hydraulic chamber, the thrust piston extends out of the pipe body, where the second preset pressure is greater than the first preset pressure.

[0021] Optionally, a second hydraulic chamber is formed between the thrust piston and the pipe string. The hydraulic assembly can inject or discharge the force-transmitting medium into or from the second hydraulic chamber, and when the force-transmitting medium is injected into the second hydraulic chamber, it will push the thrust piston to retract towards the pipe string.

[0022] Optionally, one end of the second hydraulic chamber is sealed by the thrust piston, and the other end of the second hydraulic chamber is sealed by a compression cap screwed onto the end of the pipe string.

[0023] Optionally, a power module is integrated on the inner wall of the pipe string. The power module includes the hydraulic assembly, and the power module further includes a rotary driving assembly for driving the central pipe to rotate.

[0024] Optionally, the downhole milling device further includes a control module for adjusting the working parameters of the downhole milling device.

[0025] Optionally, the control module is arranged on the side of the power module away from the mounting seat.

[0026] Optionally, the settling assembly includes:

[0027] A filter pipe is arranged at the first end of the central pipe, and the interior of the filter pipe is communicated with the central pipe;

[0028] A ball valve for blocking or opening the first end of the central pipe.

[0029] Optionally, the pipe string includes a first pipe. The anchoring assembly is arranged on the peripheral wall of the first pipe, and a first hydraulic chamber is formed between the first pipe and the central pipe. A second hydraulic chamber is formed between the first pipe and the thrust piston. The power module is arranged on the inner wall of the first pipe to seal one end of the first hydraulic chamber away from the mounting seat.

[0030] Optionally, the pipe string further includes a second pipe detachably connected to the first pipe, and the settling assembly is arranged inside the second pipe.

[0031] Optionally, the pipe string further includes a third pipe detachably connected to the second pipe, and the pump suction assembly is disposed inside the third pipe.

[0032] Optionally, the pipe string further includes a fourth pipe detachably connected to the third pipe, and the control module is disposed inside the fourth pipe.

[0033] Optionally, a connector is provided at one end of the fourth pipe away from the third pipe, and a through hole communicating with the inside of the fourth pipe is provided in the middle of the connector.

[0034] Optionally, the downhole milling device further includes a cable for connecting to the connector.

[0035] The technical solution provided by the embodiment of the present invention has the following advantages compared with the prior art:

[0036] The downhole milling device provided by the present invention can drive the mounting seat to move along the axial direction of the central pipe through the axial driving assembly, and then drive the milling assembly connected thereto along the axial direction of the central pipe through the mounting seat, so as to provide drilling pressure for the milling assembly through the axial driving assembly to ensure the milling effect of the milling assembly. Moreover, the pump suction assembly provides power for the fluid, so that the fluid carries debris and flows out upward through the pipe body, and the debris carried by the fluid is collected by the settling assembly, effectively solving the problem that the traditional chip-carrying methods such as mud and plugging agents cause great pollution to the formation during milling construction in large-loss wells, and at the same time avoiding the situation that the debris generated during milling settles in the horizontal section and causes pipe string jamming, ensuring the smooth progress of the construction. During the working process, only the settling assembly needs to be periodically tripped out for cleaning, thereby effectively reducing the construction risk and cost, shortening the construction period, and reducing the labor intensity of workers. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] The drawings here are incorporated into the specification and form a part of this specification, showing embodiments consistent with the present invention and used together with the specification to explain the principles of the present invention.

[0038] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required for use in the description of the embodiments or the prior art. Obviously, for those of ordinary skill in the art, other drawings can also be obtained based on these drawings without creative efforts.

[0039] Figure 1 It is a schematic structural diagram of the downhole milling device according to the embodiment of the present invention;

[0040] Figure 2 It is a schematic structural diagram of the settling assembly according to the embodiment of the present invention;

[0041] Figure 3 Schematic structural diagram of the anchoring component according to the embodiment of the present invention;

[0042] Figure 4 Schematic structural diagram of the mounting base according to the embodiment of the present invention.

[0043] Description of the reference numerals in the drawings

[0044] 1. Pipe body; 11. Pipe column; 111. Anchoring hole; 112. First pipe; 113. Second pipe; 114. Third pipe; 115. Fourth pipe; 116. Connector; 12. Central pipe; 121. Input shaft; 13. First hydraulic chamber; 14. Second hydraulic chamber; 15. Compression cap; 2. Settlement component; 21. Filter pipe; 22. Ball valve; 3. Pump suction component; 4. Mounting base; 41. Output shaft; 42. Speed change component; 43. Back cap; 5. Axial drive component; 51. Thrust piston; 6. Anchoring component; 61. Anchor claw; 62. Cover plate; 7. Power module; 8. Control module. Detailed implementation manners

[0045] In order to more clearly understand the above objects, features and advantages of the present invention, the solution of the present invention will be further described below. It should be noted that, without conflict, the embodiments of the present invention and the features in the embodiments can be combined with each other.

[0046] Many specific details are set forth in the following description in order to provide a thorough understanding of the present invention, but the present invention may be practiced in other ways different from those described herein; obviously, the embodiments in the specification are only a part of the embodiments of the present invention, rather than all of the embodiments.

[0047] Combined with Figures 1 to 4 As shown, the downhole milling device provided by the embodiment of the present invention includes a pipe body 1, a settlement component 2, a pump suction component 3, a mounting base 4 and an axial drive component 5.

[0048] As Figure 1 As shown, the pipe body 1 includes a pipe column 11 and a central pipe 12 inserted through one end of the pipe column 11, and the central pipe 12 is coaxially arranged with the pipe body 1. The central pipe 12 has a first end extending into the interior of the pipe column 11 and a second end extending out of the pipe column 11. Taking Figure 1 the direction shown as an example, the first end of the central pipe 12 is the right end of the central pipe 12 (the top end of the central pipe 12 during use), and the second end of the central pipe 12 is the left end of the central pipe 12 (the bottom end of the central pipe 12 during use).

[0049] The settling component 2 is arranged at the first end of the central pipe 12 (during use, the settling component 2 is located at the top end of the central pipe 12). The settling component 2 is configured to filter and collect the debris entrained in the fluid passing through the settling component 2. In this design, when the fluid passing through the central pipe 12 flows upward, the fluid carrying debris will pass through the settling component 2 to filter and collect the debris through the settling component 2, so as to ensure the circulation effect of the fluid.

[0050] The pump suction component 3 is arranged at the end of the settling component 2 far from the pipe body 1 (during use, the pump suction component 3 is located at the top end of the settling component 2). The pump suction component 3 is used to provide a force for the fluid in the direction from the second end of the central pipe 12 towards the first end of the central pipe 12, that is, the pump suction component 3 is used to provide a bottom-up force for the fluid, so that the fluid can flow from the bottom of the pipe body 1 to the top of the pipe body 1. At this time, the circulation mode of the circulation system is: the fluid flows downward in the annulus between the pipe body 1 and the casing, and the fluid flows upward in the pipe body 1. This circulation mode enables the debris generated during the milling process to be directly transported upward through the pipe body 1 and the debris to be collected by the settling component 2.

[0051] Among them, the pump suction component 3 can be a motor pump structure, which is a permanent component for fluid drainage. The structure and working principle of it are not described in detail here. After the motor pump is started, the fluid in the well enters the tool, is filtered through the settling component 2, and the debris in the fluid is left in the tool, and the cleaned fluid is discharged from the tool.

[0052] The mounting seat 4 is arranged at the second end of the central pipe 12 (during use, the mounting seat 4 is located at the bottom end of the central pipe 12). An output shaft 41 for installing the milling component is provided at the end of the mounting seat 4 far from the pipe body 1, and the central pipe 12 can drive the output shaft 41 to rotate. Specifically, the milling component is arranged on the output shaft 41 of the mounting seat 4, so as to drive the output shaft 41 to rotate through the central pipe 12, and then transmit the power to the milling component through the output shaft 41, so as to provide a rotational force for the milling component through the internal structure of the pipe body 1. Among them, the milling component can be replaced with tools such as flat mills, cone bits, and scrapers according to actual needs. The output shaft 41 is connected to the mounting seat 4 through a bearing to ensure the smoothness of the rotation of the output shaft 41, and the end of the mounting seat far from the central pipe 12 can be tightened by a back cap 43 to ensure the tightness of the internal structure of the mounting seat 4.

[0053] The axial driving assembly 5 is arranged on the pipe body 1 and is used to drive the mounting seat 4 to move along the axial direction of the pipe body 1. Among them, the way of arranging the axial driving assembly 5 on the pipe body 1 is not limited. For example, the axial driving assembly 5 can be arranged on the inner wall of the pipe string 11 so as to drive the mounting seat 4 to move along the axial direction of the pipe body 1 through the axial driving assembly 5, so that the milling assembly can move along the vertical direction after extending into the casing. Specifically, during the milling process, the milling assembly is driven to move downward by the axial driving assembly 5 so that the milling assembly presses against the part to be milled to ensure the milling effect of the part to be milled.

[0054] The downhole milling device provided by the present invention can drive the mounting seat 4 to move along the axial direction of the central pipe 12 through the axial driving assembly 5, and then drive the milling assembly connected thereto to move along the axial direction of the central pipe 12 through the mounting seat 4, so as to provide the drilling pressure for the milling assembly through the axial driving assembly 5 to ensure the milling effect of the milling assembly. Moreover, the pump suction assembly 3 provides power for the fluid, so that the fluid carries debris and flows out upward through the pipe body 1, and the debris carried by the fluid is collected by the sedimentation assembly 2, effectively solving the problem that the traditional chip-carrying methods such as mud and plugging agents cause greater pollution to the formation during milling construction in large leakage wells. At the same time, it avoids the situation that the debris generated during the milling process settles in the horizontal section and causes the pipe string 11 to get stuck, ensuring the smooth progress of the construction. During the working process, only the sedimentation assembly 2 needs to be lifted regularly to clean it, without frequent lifting of the drill string, thereby effectively reducing the construction risk and construction cost, shortening the construction period, and reducing the labor intensity of workers.

[0055] Combined with Figure 1 and Figure 3 As shown, the downhole milling device further includes an anchoring assembly 6 arranged inside the pipe string 11. The anchoring assembly 6 enables the tool string to withstand the reaction force during the milling process and provides a downward pressure. The anchoring assembly 6 is arranged to be able to extend out of the pipe string 11 to anchor to the casing or retract into the inside of the pipe string 11, so as to be able to position the pipe body 1 through the anchoring assembly 6. In this design, when the pipe body 1 is placed at the preset position and the part to be milled needs to be milled by the milling assembly, the anchoring assembly 6 extends out of the pipe string 11 to anchor on the inner wall of the casing. At this time, the axial driving assembly 5 drives the milling assembly to move downward to pressurize the milling surface to ensure the milling effect of the milling assembly. At this time, the anchoring assembly 6 can provide a supporting force for the pressurization of the axial driving assembly 5 to ensure the pressing effect of the axial driving assembly 5.

[0056] In some embodiments, continue to refer to Figure 1 and Figure 3, a first hydraulic chamber 13 is formed between the pipe string 11 and the central pipe 12. The first hydraulic chamber 13 is filled with a force-transmitting medium. The first hydraulic chamber 13 should be a closed chamber to prevent leakage of the force-transmitting medium and ensure the pressurization effect. Among them, the force-transmitting medium can be hydraulic oil, etc. Inside the pipe string 11, there is a hydraulic component for injecting or discharging the force-transmitting medium into the first hydraulic chamber 13. Specifically, the hydraulic component has a first liquid pipeline communicating with the first hydraulic chamber 13. The hydraulic component can inject the force-transmitting medium into the first hydraulic chamber 13 through the first liquid pipeline, or the force-transmitting medium in the first hydraulic chamber 13 can flow back into the hydraulic component through the first liquid pipeline. Among them, the anchoring component 6 is penetrated through the peripheral wall of the pipe string 11. The anchoring component 6 is arranged to extend out of the pipe string 11 when the force-transmitting medium with a first preset pressure is injected into the first hydraulic chamber 13; when the pressure of the force-transmitting medium in the first hydraulic chamber 13 is lower than the first preset pressure, the anchoring component 6 retracts into the pipe string 11. Among them, the first preset pressure is the minimum pressure when the anchoring component 6 can move relative to the pipe string 11 and can be designed according to actual requirements. In this design method, the anchoring component 6 can be extended out of the pipe string 11 and anchored on the inner wall of the casing by pressurizing the force-transmitting medium. When the pressure of the force-transmitting medium is removed, the anchoring component 6 can retract into the interior of the pipe string 11 to prevent the entire pipe body 1 from moving in the casing.

[0057] As Figure 3 shown, as a feasible implementation manner, an anchoring hole 111 communicating with the first hydraulic chamber 13 is provided on the peripheral wall of the pipe string 11. The anchoring hole 111 is a through-hole structure. The anchoring component 6 includes an anchor claw 61 and a reset member. The anchor claw 61 is arranged in the anchoring hole 111. The anchor claw 61 is sealingly connected to the inner wall of the anchoring hole 111 to prevent the force-transmitting medium from flowing out through the gap between the outer periphery of the anchor claw 61 and the inner wall of the anchoring hole 111, ensuring that the pressure of the force-transmitting medium acts on the anchor claw 61. Among them, the outer periphery of the anchor claw 61 and the inner wall of the anchoring hole 111 can be sealed by a sealing ring to ensure the sealing effect. The reset member is used to provide a force acting on the anchor claw 61 in the direction of the first hydraulic chamber 13. When the pressure acting on the anchor claw 61 disappears, the reset member can drive the anchor claw 61 to move in the direction of the first hydraulic chamber 13, so that the anchor claw 61 can retract into the pipe string 11. Among them, the appropriate number of anchoring holes 111 and anchor claws 61 can be designed according to actual requirements.

[0058] Specifically, a cover plate 62 is provided at one end of the anchoring hole 111 away from the first hydraulic chamber 13. The cover plate 62 is arranged on the pipe string 11 through bolts to increase the convenience of disassembly and assembly of the cover plate 62. The reset member includes a reset spring arranged between the cover plate 62 and the anchor claw 61. The cover plate 62 is provided with an avoidance hole through which the anchoring end of the anchor claw 61 can extend. In this design, the anchor claw 61 can be limited in the anchoring hole 111 by the cover plate 62. The anchor claw 61 includes a sliding end and an anchoring end. The sliding end is slidably arranged in the anchoring hole 111, and the anchoring end can extend out of the avoidance hole to anchor on the inner wall of the casing. The design of the cover plate 62 facilitates the arrangement of the reset spring, so that the cover plate 62, the reset spring and the anchor claw 61 are arranged in the anchoring hole 111 from outside to inside. Among them, the reset spring can be a cylindrical spring, a combined spring, a rectangular spring, etc., and these are not restrictive.

[0059] Further optimized, a guide post can also be arranged on the anchor claw 61, and the reset spring is sleeved on the outer periphery of the guide post to play a guiding role in the expansion and contraction of the reset spring through the guide post, ensuring that the acting force direction of the reset spring meets its use requirements.

[0060] Combined Figure 1 and Figure 4 As shown, an input shaft 121 is sleeved on the outer periphery of the second end of the central tube 12. The central tube 12 is used to drive the input shaft 121 to rotate, that is, the central tube 12 can drive the input shaft 121 to rotate coaxially, and the input shaft 121 can move relative to the central tube 12 along the axial direction of the central tube 12. Furthermore, when the axial driving assembly 5 drives the mounting seat 4 to move along the axial direction of the pipe body 1, the input shaft 121 can also move along with the mounting seat 4, so that the milling assembly arranged at the end of the mounting seat 4 can perform axial movement and circumferential rotation to meet the use requirements. A speed change assembly 42 is arranged inside the mounting seat 4, and the input shaft 121 drives the output shaft 41 to rotate through the speed change assembly 42.

[0061] Specifically, the speed change assembly 42 can be a speed reducer. The speed reducer has a first shaft and a second shaft. The first shaft is used for power input, and the second shaft is used for power output. A first gear is arranged on the outer periphery of the input shaft 121, a second gear meshing with the first gear is arranged on the outer periphery of the first shaft of the speed reducer, a third gear is arranged on the outer periphery of the second shaft, and a fourth gear for meshing with the third gear is arranged on the outer periphery of the output shaft 41. Among them, the specific design of the speed reducer is not limited and can be designed according to actual needs, as long as it ensures that the rotation speed transmitted to the output shaft 41 meets the use requirements of the milling assembly.

[0062] In some embodiments, a guiding protrusion is provided on the outer periphery of the central tube 12. The guiding protrusion extends along the axial direction of the central tube 12. A guiding groove matching the guiding protrusion is provided on the inner wall of the input shaft 121. During installation, the guiding protrusion is snapped into the guiding groove so that the input shaft 121 can move along the axial direction of the central tube 12 under the action of the guiding protrusion and the guiding groove. At the same time, under the circumferential limit of the guiding protrusion and the guiding groove, the central tube 12 and the input shaft 121 cannot rotate relative to each other along the circumferential direction of the central tube 12, thereby ensuring that the central tube 12 drives the input shaft 121 to rotate synchronously.

[0063] In other embodiments, a guiding groove is provided on the outer periphery of the central tube 12. A guiding protrusion matching the guiding groove is provided on the inner wall of the input shaft 121. The guiding protrusion extends along the axial direction of the central tube 12. Similarly, during installation, the guiding protrusion is snapped into the guiding groove so that the input shaft 121 can move along the axial direction of the central tube 12 under the action of the guiding protrusion and the guiding groove. At the same time, under the circumferential limit of the guiding protrusion and the guiding groove, the central tube 12 and the input shaft 121 cannot rotate relative to each other along the circumferential direction of the central tube 12, thereby ensuring that the central tube 12 drives the input shaft 121 to rotate synchronously.

[0064] In some embodiments, in combination Figure 1 and Figure 3 As shown, the axial driving assembly 5 includes a thrust piston 51 sleeved on the outer periphery of the input shaft 121. Specifically, the thrust piston 51 is arranged in the annular gap between the input shaft 121 and the pipe string 11. The input shaft 121 and the thrust piston 51 can rotate relative to each other so that the thrust piston 51 does not affect the rotation of the central tube 12 driving the input shaft 121, thereby avoiding affecting the rotation of the output shaft 41.

[0065] One end of the thrust piston 51 extending into the pipe string 11 is used to seal the end of the first hydraulic chamber 13. One end of the thrust piston 51 extending out of the pipe string 11 is connected to the mounting seat 4. Specifically, an annular protrusion is provided at one end of the thrust piston 51 extending into the pipe string 11. The annular protrusion extends out of the thrust piston 51 towards the direction of the input shaft 121 so that the annular protrusion can support on the outer periphery of the central tube 12. The annular protrusion also extends out of the thrust piston 51 in the direction away from the input shaft 121 so that the annular protrusion can support on the inner wall of the pipe string 11, thereby realizing the sealing of the end of the first hydraulic chamber 13. In addition, one end of the input shaft 121 extending into the pipe string 11 can support on the annular protrusion so that the input shaft 121 can be driven by the thrust piston 51 to extend out of the pipe string 11. The thrust piston 51 and the mounting seat 4 can be connected by a threaded manner to increase the convenience of disassembly and the firmness of connection so that the mounting seat 4 can move synchronously with the thrust piston 51.

[0066] The thrust piston 51 is configured to extend out of the pipe body 1 when a force - transmitting medium with a second preset pressure is injected into the first hydraulic chamber 13, where the second preset pressure is greater than the first preset pressure. The second preset pressure is the minimum pressure at which the thrust piston 51 can move relative to the pipe string 11, and the design that the second preset pressure is greater than the first preset pressure enables the anchoring assembly 6 to work first and the thrust piston 51 to work later, so as to meet the working requirements of the downhole milling device.

[0067] During use, after the pipe body 1 moves to a preset position, the force - transmitting medium can be filled into the first hydraulic chamber 13 through the hydraulic assembly. When the pressure of the force - transmitting medium in the first hydraulic chamber 13 reaches the first preset pressure, the anchor claws 61 extend out to anchor the pipe body 1 on the inner wall of the casing through the anchor claws 61. At this time, continue to pressurize until the pressure of the force - transmitting medium in the first hydraulic chamber 13 reaches the second preset pressure, then the thrust piston 51 will extend out of the pipe string 11 to drive the milling assembly arranged at the end of the mounting seat 4 to move downward, ensuring the milling effect of the milling assembly. The thrust piston 51 can be reset by the internal - external pressure difference caused by upward movement and the self - weight of the tool.

[0068] In this design, on the one hand, the hydraulic assembly is used as the driving structure of the anchoring assembly 6, and on the other hand, the hydraulic assembly can also be used as the driving structure of the thrust piston 51, so as to reduce the cost of power equipment and make the overall structure of the downhole milling device more compact.

[0069] In some other embodiments, a second hydraulic chamber 14 is formed between the thrust piston 51 and the pipe string 11. The hydraulic assembly can inject or discharge the force - transmitting medium into or from the second hydraulic chamber 14, and when the force - transmitting medium is injected into the second hydraulic chamber 14, it will push the thrust piston 51 to retract towards the pipe string 11. Specifically, the hydraulic assembly has a second liquid pipeline communicating with the second hydraulic chamber 14. The hydraulic assembly can inject the force - transmitting medium into the second hydraulic chamber 14 through the second liquid pipeline, or the force - transmitting medium in the second hydraulic chamber 14 can flow back into the hydraulic assembly through the second liquid pipeline. When it is necessary to move the downhole milling device, the force - transmitting medium can be injected into the second hydraulic chamber 14 through the hydraulic assembly, so that the thrust piston 51 retracts towards the pipe string 11, and the mounting seat 4 and the milling assembly can be driven by the thrust piston 51 to move upward. At this time, the force - transmitting medium in the first hydraulic chamber 13 flows back to the hydraulic assembly. This design facilitates the position adjustment of the milling assembly along the axial direction of the pipe string 11.

[0070] One end of the second hydraulic chamber 14 is sealed by a thrust piston 51, and the other end of the second hydraulic chamber 14 is sealed by a compression cap 15 screwed onto the end of the pipe string 11. Specifically, as described above, an annular protrusion is provided at one end of the thrust piston 51 extending into the pipe string 11, and the annular protrusion extends out of the thrust piston 51 in a direction away from the input shaft 121, so that the annular protrusion can support on the inner wall of the pipe string 11, specifically on the inner wall of the second hydraulic chamber 14, to ensure the sealing effect at the end of the second hydraulic chamber 14 and limit the movement of the thrust piston 51 through the second hydraulic chamber 14. The compression cap 15 is screwed onto the end of the pipe string 11 by means of threads to increase the convenience of disassembly and assembly of the compression cap 15 and at the same time increase the convenience of disassembly and assembly of the thrust piston 51, and the inner side of the compression cap 15 supports on the outer periphery of the thrust piston 51 to ensure the sealing effect at the end of the second hydraulic chamber 14 and enable the thrust piston 51 to move along the axial direction of the pipe string 11 relative to the compression cap 15.

[0071] A power module 7 is integrated on the inner wall of the pipe string 11. Among them, the power module 7 can be used to block one end of the first hydraulic chamber 13 away from the mounting seat 4 to ensure the sealing effect of the first hydraulic chamber 13. The power module 7 includes a hydraulic component, and the power module 7 further includes a rotary drive component for driving the central tube 12 to rotate, so as to be able to drive the central tube 12 to rotate through the rotary drive component. The power module 7 may include a housing, and both the hydraulic component and the rotary drive component are arranged in the housing. Among them, the integrated manner of the power module 7 can reduce the space occupation. At this time, the power module 7 provides rotational power for the central tube 12 to drive the speed-changing component 42 to perform speed reduction and torque increase and transmit it to the output shaft 41 and the milling component, so that the milling component can perform milling operations. In addition, the power module 7 provides pressure for the movement of the thrust piston 51 and the anchoring of the anchoring component 6, so that the anchoring component 6 can be anchored on the inner wall of the casing to provide counter torque and support for the device.

[0072] In some embodiments, the rotary drive component includes a drive motor and a speed reducer arranged at the output end of the drive motor. A fifth gear is provided at the output end of the speed reducer, so that the power transmitted by the drive motor can be transmitted to the fifth gear through the speed reducer. A sixth gear meshing with the fifth gear is provided on the outer periphery of the first end of the central tube 12. Then, as the drive motor rotates, the power can be transmitted to the central tube 12 through the speed reducer, the fifth gear and the sixth gear, thereby realizing the rotation of the central tube 12. Among them, the specific connection manner between the drive motor and the speed reducer is not limited and can be selected according to actual needs.

[0073] In some embodiments, the downhole milling device further includes a control module 8 for adjusting the operating parameters of the downhole milling device. Specifically, the power module 7 can be adjusted through the control module 8, specifically adjusting the operating parameters of the hydraulic components and the rotary drive components of the power module 7, so that the anchoring component 6, the thrust piston 51, and the milling component can perform corresponding operations according to a preset program. Among them, the control module 8 is the control core of the entire device. By an operator sending instructions to the control module 8 on the ground, functions such as downhole tool anchoring, propulsion, and milling are realized. The control module 8 has functions such as displaying voltage values, current values, stroke positions, etc. In addition, the control module 8 also has an overload protection function to ensure safe use. Among them, the control method and adjustment method of the control module 8 are conventional technologies in the art. Therefore, the working principle and control method thereof are not described in detail herein. In this design method, the downhole milling device is used as a downhole electric milling device and can achieve automatic control.

[0074] Further optimized, the control module 8 is arranged on the side of the power module 7 away from the mounting seat 4. This design method rationally utilizes the internal space of the pipe string 11 to ensure the compactness of the overall structure.

[0075] In some embodiments, as Figure 2 shown, the settling component 2 includes a filter pipe 21 and a ball valve 22. The filter pipe 21 is arranged at the first end of the central pipe 12, and the inside of the filter pipe 21 is communicated with the central pipe 12 so that the fluid can carry debris and flow towards the filter pipe 21. Among them, the filter pipe 21 is evenly distributed with sieve holes. The filter pipe 21 can filter the debris in the fluid but allows the fluid to pass through. The filter pipe 21 can be replaced with different mesh numbers or magnetic filter pipes 21 according to the material of the mill shoe and the fish top to ensure filtering of debris and not affect the flow of the fluid at the same time. The ball valve 22 is used to block or open the first end of the central pipe 12.

[0076] In this design method, during use, the ball valve 22 is above the central pipe 12. At this time, the ball valve 22 blocks the first end of the central pipe 12 under the action of gravity. When the fluid flows towards the filter pipe 21, the fluid will push open the ball valve 22 so that the fluid carrying debris can flow through the central pipe 12 towards the filter pipe 21 to filter out the debris through the filter pipe 21, and the debris has a tendency to move towards the top of the filter pipe 21. Therefore, the debris will not flow back from the connection between the central pipe 12 and the filter pipe 21. And when the amount of debris collected by the filter pipe 21 reaches the preset debris amount, the device stops running. At this time, the ball valve 22 drops to block the end of the central pipe 12, and the impurities stay in the filter pipe 21.

[0077] Further optimized, a tapered section is provided at the part of the filter tube 21 connected to the central tube 12. Here, the tapered section can be provided at one end of the filter tube 21 facing the central tube 12, or the tapered section can be provided at one end of the central tube 12 facing the filter tube 21, and these are not restrictive. The setting method of the tapered section can facilitate the ball valve 22 to fall under gravity to the constriction position of the tapered section, so as to facilitate the ball valve 22 to block the end of the central tube 12.

[0078] As Figure 1 shown, the pipe string 11 of the present application includes a first pipe 112, an anchoring assembly 6 is arranged on the peripheral wall of the first pipe 112, and a first hydraulic cavity 13 is formed between the first pipe 112 and the central pipe 12, and a second hydraulic cavity 14 is formed between the first pipe 112 and the thrust piston 51. The power module 7 is arranged on the inner wall of the first pipe 112 to seal one end of the first hydraulic cavity 13 away from the mounting seat 4. Under this design method, the pipe string 11 adopts a split design method, which is convenient for the disassembly and assembly of the anchoring assembly 6 and the power module 7 in the pipe string 11.

[0079] The pipe string 11 further includes a second pipe 113 detachably connected to the first pipe 112, and a sedimentation assembly 2 is arranged inside the second pipe 113. Specifically, the first pipe 112 and the second pipe 113 are connected by screwing to increase the convenience of disassembly and assembly between the first pipe 112 and the second pipe 113. The sedimentation assembly 2 is arranged on the inner wall of the second pipe 113. When the amount of debris collected by the sedimentation assembly 2 reaches the preset requirement, the second pipe 113 can be removed to clean or replace the sedimentation assembly 2, increasing the convenience of operation. Among them, the end of the second pipe 113 is screwed inside the first pipe 112 and supported on the power module 7 through the end of the second pipe 113 to ensure the positioning effect of the power module 7 and make the connection between components more compact.

[0080] The pipe string 11 further includes a third pipe 114 detachably connected to the second pipe 113, and a pump suction assembly 3 is arranged inside the third pipe 114. Specifically, the second pipe 113 and the third pipe 114 are connected by screwing to increase the convenience of disassembly and assembly between the second pipe 113 and the third pipe 114. The pump suction assembly 3 is arranged on the inner wall of the third pipe 114 to facilitate the disassembly and assembly of the pump suction assembly 3 and the assembly of the pump suction assembly 3 and the pipe string 11. And when the pump suction assembly 3 fails, the third pipe 114 can be removed for separate repair of the pump suction assembly 3, increasing the maintenance efficiency.

[0081] The pipe string 11 further includes a fourth pipe 115 detachably connected to the third pipe 114, and the control module 8 is disposed inside the fourth pipe 115. Specifically, the third pipe 114 and the fourth pipe 115 are connected by screwing, so as to increase the convenience of disassembly and assembly between the third pipe 114 and the fourth pipe 115, and the control module 8 is disposed on the inner wall of the fourth pipe 115. In this design, independent assembly of each component can be achieved, and the convenience of maintenance of each component is increased.

[0082] One end of the fourth pipe 115 away from the third pipe 114 is provided with a connector 116, and a through hole communicating with the inside of the fourth pipe 115 is provided in the middle of the connector 116. Among them, the connector 116 and the fourth pipe 115 are connected by screwing, which increases the convenience of disassembly and assembly, and the end of the connector 116 should be inserted inside the fourth pipe 115 to press against the control module 8 through the end of the connector 116, making the overall structure more compact.

[0083] During use, the fluid in the pipe string 11 will flow out through the connector 116 and enter the annular space between the pipe body 1 and the casing to continue to participate in the fluid circulation.

[0084] The downhole milling device provided by the present application further includes a cable for connecting with the connector 116, wherein the cable is not shown in the drawings. The connection method between the cable and the connector 116 is not limited and can be designed according to actual requirements. By providing the cable, the construction does not require a pipe string, the cable running speed is fast, and the convenience of lifting or lowering the downhole milling device is increased.

[0085] The working process of the downhole milling device provided by the present invention is as follows:

[0086] Step S1, on the ground, the cable is connected to the downhole milling device;

[0087] Step S2, the cable is lowered into the well by a cable car until the fish top, the depth is repeatedly verified, and the downhole milling device is brought into contact with the fish top;

[0088] Step S3, after the position is accurate, the ground operator sends an instruction by computer, and the control module 8 drives the power module 7 to compress the force transmission medium in the first hydraulic chamber 13 to realize the extension of the anchor claw 61 and anchor to the casing;

[0089] Step S4, lift the cable to test whether the anchoring is reliable. If the anchoring is not reliable, change the control parameters (voltage value, current value), and repeat the anchoring process until the anchoring is reliable before proceeding to the next process;

[0090] Step S5, after the anchoring is reliable, the ground operator sends an instruction by computer, and the control module 8 drives the power module 7, and the pressure of the force transmission medium in the first hydraulic chamber 13 continues to increase until it can push the thrust piston 51 to pressurize the milling surface.

[0091] Step S6: The milling assembly performs milling. After the ground display control module 8 stabilizes for a period of time and then the reading gradually decreases to a certain value and stabilizes, the first-stage milling construction is completed.

[0092] Step S7: The ground operator sends an instruction through the computer, and the control module 8 drives the power module 7 to reverse. The pressure of the force-transmitting medium in the first hydraulic chamber 13 decreases, and the anchor claw 61 releases the anchoring. At the same time, the downhole milling device ensures that after the anchoring is released, the tool is lowered to the fish top, and the weight of the downhole milling device is relied on to compress the thrust piston 51 to achieve reset (or the thrust piston 51 is reset by injecting the force-transmitting medium into the second hydraulic chamber 14).

[0093] Step S8: Repeat steps 3 - 7 until the design requirements are met or the maximum single-trip milling distance is exceeded.

[0094] Step S9: The ground operator sends an instruction through the computer, and the control module 8 drives the power module 7 to reverse. The pressure in the first hydraulic chamber 13 decreases, the anchor claw 61 retracts, and after the downhole milling device releases the anchoring, the tool is lifted out of the wellbore, the internal debris of the downhole milling device is cleaned, and the device is lowered back into the well for construction according to requirements.

[0095] Under this design method, the control module 8 can be controlled by a computer on the ground, which is time-saving and labor-saving in operation. The tripping speed is increased by 8 - 10 times, and the depth calibration is fast and accurate. The milling pressure is controllable, and the drilling pressure directly acts on the milling surface, without the need to overcome the torque loss caused by the pipe string 11 (such as the torque loss generated by the friction between the pipe string 11 and the casing). The energy utilization rate is increased by more than 30%; the disturbance to the well fluid is reduced, and the requirements for the circulation conditions during the milling construction are lowered. Especially for the case of serious formation leakage, construction can be carried out without the need for plugging, reducing the pollution to the formation and the operation cost.

[0096] It should be noted that in this article, relational terms such as "first" and "second" are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any actual relationship or order between these entities or operations. Moreover, the terms "include", "comprise" or any other variant thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements not only includes those elements, but also includes other elements not explicitly listed, or further includes elements inherent to such process, method, article or device. Without further limitation, an element defined by the statement "including a..." does not exclude the existence of additional identical elements in the process, method, article or device including the said element.

[0097] The above are only specific embodiments of the present invention, enabling those skilled in the art to understand or implement the present invention. Various modifications to these embodiments will be obvious to those skilled in the art, and the general principles defined herein can be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention will not be limited to these embodiments described herein, but rather to the broadest scope consistent with the principles and novel features invented herein.

Claims

1. An underground milling device, characterized in that, Comprising: A pipe body (1), including a pipe string (11) and a central pipe (12) inserted through one end of the pipe string (11), the central pipe (12) having a first end extending into the interior of the pipe string (11) and a second end extending out of the pipe string (11); A settling assembly (2), arranged at the first end of the central pipe (12), the settling assembly (2) being configured to filter and collect debris entrained in the fluid passing through the settling assembly (2); A pump suction assembly (3), arranged at the end of the settling assembly (2) away from the pipe body (1), for providing a force to the fluid in the direction from the second end of the central pipe (12) towards the first end of the central pipe (12); A mounting seat (4), arranged at the second end of the central pipe (12), an output shaft (41) for mounting a milling assembly being provided at the end of the mounting seat (4) away from the pipe body (1), and the central pipe (12) being capable of driving the output shaft (41) to rotate; An axial drive assembly (5), arranged on the pipe body (1), for driving the mounting seat (4) to move along the axial direction of the pipe body (1).

2. The downhole milling device according to claim 1, wherein, The downhole milling device further includes an anchoring assembly (6) arranged inside the pipe string (11), the anchoring assembly (6) being configured to extend out of the pipe string (11) to anchor to the casing or retract into the interior of the pipe string (11).

3. The downhole milling device according to claim 2, characterized in that, A first hydraulic chamber (13) is formed between the pipe string (11) and the central pipe (12), a hydraulic assembly for injecting or discharging a force-transmitting medium into or out of the first hydraulic chamber (13) is provided inside the pipe string (11), the anchoring assembly (6) is inserted through the peripheral wall of the pipe string (11), and the anchoring assembly (6) is configured as: Extending out of the pipe string (11) when a force-transmitting medium with a first preset pressure is injected into the first hydraulic chamber (13); When the pressure of the force-transmitting medium in the first hydraulic chamber (13) is lower than the first preset pressure, the anchoring assembly (6) retracts into the pipe string (11).

4. The downhole milling device according to claim 3, characterized in that, An anchoring hole (111) communicating with the first hydraulic chamber (13) is provided on the peripheral wall of the pipe string (11), and the anchoring assembly (6) includes: An anchor claw (61), arranged in the anchoring hole (111), the anchor claw (61) being hermetically connected to the inner wall of the anchoring hole (111); A reset member, for providing a force to the anchor claw (61) in the direction towards the first hydraulic chamber (13).

5. The downhole milling device according to claim 4, characterized in that, A cover plate (62) is provided at the end of the anchoring hole (111) away from the first hydraulic chamber (13), the reset member includes a reset spring arranged between the cover plate (62) and the anchor claw (61), and an avoidance hole through which the anchoring end of the anchor claw (61) can extend is provided on the cover plate (62).

6. The downhole milling device according to claim 3, characterized in that, An input shaft (121) is sleeved on the outer periphery of the second end of the central tube (12). The central tube (12) is used to drive the input shaft (121) to rotate, and the input shaft (121) can move relative to the central tube (12) along the axial direction of the central tube (12). A speed-changing assembly (42) is arranged inside the mounting seat (4), and the input shaft (121) drives the output shaft (41) to rotate through the speed-changing assembly (42).

7. The downhole milling device according to claim 6, characterized in that, Guide protrusions are arranged on the outer periphery of the central tube (12), and the guide protrusions extend along the axial direction of the central tube (12). Guide grooves matching the guide protrusions are arranged on the inner wall of the input shaft (121).

8. The downhole milling device according to claim 6, characterized in that, The axial driving assembly (5) includes a thrust piston (51) sleeved on the outer periphery of the input shaft (121). The input shaft (121) and the thrust piston (51) can rotate relative to each other. One end of the thrust piston (51) extending into the pipe string (11) is used to seal the end of the first hydraulic chamber (13), and one end of the thrust piston (51) extending out of the pipe string (11) is connected to the mounting seat (4). The thrust piston (51) is arranged such that when a force-transmitting medium with a second preset pressure is injected into the first hydraulic chamber (13), the thrust piston (51) extends out of the pipe body (1), wherein the second preset pressure is greater than the first preset pressure.

9. The downhole milling device according to claim 8, wherein, A second hydraulic chamber (14) is formed between the thrust piston (51) and the pipe string (11). The hydraulic assembly can inject or discharge the force-transmitting medium into or from the second hydraulic chamber (14), and when the force-transmitting medium is injected into the second hydraulic chamber (14), it will push the thrust piston (51) to retract towards the pipe string (11).

10. The downhole milling device according to claim 9, characterized in that, One end of the second hydraulic chamber (14) is sealed by the thrust piston (51), and the other end of the second hydraulic chamber (14) is sealed by a compression cap (15) screwed on the end of the pipe string (11).

11. The downhole milling device according to claim 9, characterized in that, A power module (7) is integrated on the inner wall of the pipe string (11). The power module (7) includes the hydraulic assembly, and the power module (7) further includes a rotary driving assembly for driving the central tube (12) to rotate.

12. The downhole milling device according to claim 11, wherein, The downhole milling device further includes a control module (8) for adjusting the working parameters of the downhole milling device.

13. The downhole milling device according to claim 12, wherein, The control module (8) is arranged on a side of the power module (7) away from the mounting seat (4).

14. The downhole milling device according to claim 1, characterized in that, The settling assembly (2) includes: A filter pipe (21) is arranged at the first end of the central tube (12), and the inside of the filter pipe (21) is communicated with the central tube (12). A ball valve (22) for blocking or opening the first end of the central tube (12).

15. The downhole milling device according to claim 12, wherein, The pipe string (11) includes a first pipe (112), the anchoring assembly (6) is arranged on the peripheral wall of the first pipe (112), and a first hydraulic chamber (13) is formed between the first pipe (112) and the central pipe (12). A second hydraulic chamber (14) is formed between the first pipe (112) and the thrust piston (51). The power module (7) is arranged on the inner wall of the first pipe (112) to seal one end of the first hydraulic chamber (13) away from the mounting seat (4).

16. The downhole milling device according to claim 15, characterized in that, The pipe string (11) further includes a second pipe (113) detachably connected to the first pipe (112), and the settling assembly (2) is arranged inside the second pipe (113).

17. The downhole milling device according to claim 16, wherein, The pipe string (11) further includes a third pipe (114) detachably connected to the second pipe (113), and the pump suction assembly (3) is arranged inside the third pipe (114).

18. The downhole milling device according to claim 17, wherein The pipe string (11) further includes a fourth pipe (115) detachably connected to the third pipe (114), and the control module (8) is arranged inside the fourth pipe (115).

19. The downhole milling device according to claim 18, characterized in that, One end of the fourth pipe (115) away from the third pipe (114) is provided with a connector (116), and a through hole communicating with the inside of the fourth pipe (115) is arranged in the middle of the connector (116).

20. The downhole milling device according to claim 19, wherein, The downhole milling device further includes a cable for connecting to the connector (116).

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