Wellbore tubular column inner wall cleaning tool and method

Abstract

The invention relates to the technical field of petroleum and natural gas development, in particular to a cleaning tool and method for the inner wall of a wellbore tubular column for well repair operation of production wells such as daily oil wells, natural gas wells and water injection wells, and the cleaning tool for the inner wall of the wellbore tubular column comprises a barrel, a first piston, a second piston and a plugging piece. A first channel is arranged in the cylinder body in the axial direction, and through holes are formed in the periphery of the cylinder body; the first piston and the second piston are movably arranged at the two ends of the first channel in the axial direction of the barrel pipe body, and the outer walls of the first piston and the second piston are attached to the inner wall of the first channel; a second channel is formed in the second piston in the axial direction of the barrel, and the water outlet end of the second channel faces the first piston and communicates with the first channel; the blocking piece movably blocks the water inlet end of the second channel. Under-pressure operation can be achieved when a pipe column is put in and pulled out, the most basic process preparation is provided for an existing workover treatment technology, and shaft cleaning is achieved.

Description

Technical Field

[0001] The invention belongs to the technical field of oil and natural gas development, and in particular relates to a tool and method for cleaning the inner wall of a wellbore pipe string. Background Art

[0002] During the extraction of oil and natural gas, single-branch tubing is often used as the production string, creating a continuous channel for oil and gas extraction. During routine crude oil extraction from oil wells, long-chain hydrocarbons gradually solidify as pressure and temperature fluctuations occur. These compounds, combined with sand and water scale, adsorb onto the inner walls of the tubing, impacting crude oil extraction efficiency. During the extraction of natural gas from gas wells, produced water from the reservoir, as a result of fluctuations in pressure, temperature, and liquid-carrying velocity, can also cause scaling on the inner walls of the tubing. This reduces the flow area, hindering subsequent recovery processes and impacting gas extraction efficiency. Furthermore, water injection wells, a common method for stabilizing oilfield production, typically inject produced water at high pressure through the tubing into the target formation at the bottom of the well. The scaling tendency of produced water during injection further reduces the flow area of ​​the tubing, reducing the reliability of surface equipment and facilities. Therefore, all three types of oil and gas field production wells require regular tubing cleaning.

[0003] The inner wall of the existing oil pipe can be cleaned by water injection, especially by reinjecting the produced water from the oil and gas field. This can save water resources while fully replenishing the energy of the formation to ensure the continuous extraction of oil and gas. However, the produced water from the oil and gas field is easily affected by the water type and salinity, which can easily cause scaling on the inner wall of the oil pipe, thereby increasing the injection pressure when the produced water from the oil and gas field is reinjected. The increase in injection pressure is likely to cause damage to the parts of the water injection equipment, thereby increasing the production interruption cost and equipment maintenance cost, and creating a greater safety risk. For example, the patent document with publication number CN209025650U discloses a downhole tubing flushing device for oil and water wells. It is a device for flushing crude oil attached to the surface of the downhole tubing of the oil and water well at the wellhead of the oil and water well operation site in the petroleum industry, protecting the environment and improving operation efficiency. The downhole tubing flushing device includes a mud umbrella and a leak-proof pipe. The mud umbrella is fixed to the lower part of the liquid inlet hole of the leak-proof pipe. The leak-proof pipe is connected to the flushing pipe by a flange and connecting bolts. The puncture and flushing port is provided on the pipe body of the flushing pipe. A liquid storage bag is provided on the outside of the puncture and flushing port. The outer wall of the liquid storage bag is provided with a liquid inlet, and the liquid outlet is provided on the pipe body of the flushing pipe below the liquid storage bag. Summary of the Invention

[0004] In response to the above problems, and for daily workover operations of production wells such as oil wells, natural gas wells, and water injection wells, the present invention proposes a wellbore tubular inner wall cleaning tool, comprising: A cylinder body, wherein a first passage is axially provided in the cylinder body and a through hole is opened on the outer circumference of the cylinder body; a first piston, the first piston being movably disposed at one end of the first channel along the axial direction of the cylinder body, with an outer wall of the first piston being in contact with an inner wall of the first channel; a second piston, the second piston being movably disposed at the other end of the first channel along the axial direction of the cylinder, and the outer wall of the second piston being in contact with the inner wall of the first channel; A second channel is opened in the second piston along the axial direction of the cylinder, and the water outlet end of the second channel is arranged toward the first piston and communicated with the first channel; A blocking piece is movably arranged at the water inlet end of the second channel.

[0005] In some specific embodiments, a tube is coaxially rotatably provided on the inner wall of the cylinder, so that the inner wall of the tube encloses the first channel; A through groove is provided on the outer circumference of the tube body. When the through hole overlaps with the through groove, the through hole is communicated with the first channel.

[0006] In some specific embodiments, two thrust bearings are coaxially rotatably provided on the inner wall of the cylinder, and the tube body is located between the two thrust bearings; One of the thrust bearings is rotatably sleeved on the outer periphery of the first piston, and the other thrust bearing is rotatably sleeved on the outer periphery of the second piston.

[0007] In some specific embodiments, a first external convex platform is provided on the outer wall of the first piston, and a second external convex platform is provided on the outer wall of the second piston; A third inner boss is provided on the inner wall of the cylinder, and when the first piston moves away from the second piston to a first preset position along the axial direction of the cylinder, the third inner boss is engaged with the first outer boss; A fourth inner boss is provided on the inner wall of the tube body. When the second piston moves away from the first piston to a second preset position along the axial direction of the cylinder body, the fourth inner boss is engaged with the second outer boss.

[0008] In some specific embodiments, the first piston is connected to the cylinder via a first shear pin; The second piston is connected to the cylinder via a second shear pin; When the pressure exerted on the first piston in the axial direction of the cylinder reaches a first pressure value, the first shear pin breaks; When the pressure exerted on the second piston in the axial direction of the cylinder reaches a second pressure value, the second shear pin breaks.

[0009] In some specific embodiments, the through holes are provided in a plurality of groups, and each group of the through holes includes a plurality of the through holes; The plurality of groups of through holes are evenly arranged along the circumference of the cylinder, and the plurality of through holes in each group of through holes are evenly arranged along the axial direction of the cylinder; The through slots are provided in multiple groups, and each group of the through slots includes multiple through slots; The plurality of groups of through grooves are evenly arranged along the axial direction of the cylinder, and the plurality of through grooves in each group of through grooves are evenly arranged along the circumferential direction of the cylinder.

[0010] In some specific embodiments, the plurality of groups of through holes are staggered along the axial direction of the cylinder.

[0011] In some specific embodiments, a plurality of isolation rings are disposed around the outer wall of the tube; An isolation zone is formed between two adjacent isolation rings; The plurality of isolation zones correspond to the plurality of through slots in a one-to-one manner.

[0012] In some specific embodiments, the angle between the center line of the through hole and the axis of the cylinder is in the range of 40 degrees to 50 degrees; The angle between the end connecting line of the through groove and the axis of the cylinder is in the range of 40 degrees to 50 degrees.

[0013] A method for cleaning the inner wall of a wellbore tubular string based on the same concept, using the wellbore tubular string inner wall cleaning tool as described in any of the above specific embodiments, includes the following steps: Lower the wellbore tubing inner wall cleaning tool into the wellbore to the position to be cleaned; The cleaning liquid is delivered to the second channel of the second piston. The cleaning liquid passes through the second channel and reaches the first channel in the cylinder through the water outlet of the second channel, exerting pressure on the first piston and pushing the first piston to move along the axial direction of the cylinder until the first piston is misaligned with the through hole of the cylinder, so that the through hole is connected to the first channel. Continuously deliver the cleaning fluid so that it is ejected from the through hole to clean the inner wall of the wellbore; After cleaning is completed, the blocking piece is lowered to block the water inlet end of the second channel, and the cleaning liquid is continued to be supplied to apply pressure to the second piston and push the second piston to move along the axial direction of the cylinder until the second piston coincides with the through hole to block the through hole.

[0014] Compared to the prior art, the wellbore tubular inner wall cleaning tool of the present invention has at least the following advantages: The first piston, after the cleaning fluid enters the first channel, applies pressure to the first piston and propels it axially along the barrel. This movement of the first piston provides a buffer, maintaining the starting pressure during cleaning within a safe range, thereby reducing pressure on components and ensuring the safety of wellhead workers and equipment. After cleaning is complete, the movement of the second piston seals the through-hole, halting further cleaning. The second piston then provides another buffer, further reducing pressure on components and ensuring the safety of wellhead workers and equipment, thereby achieving safe removal of the tubular. Furthermore, the wellbore tubular inner wall cleaning tool is adaptable to all existing workover tubulars, enabling pressure-bearing operations during both "running" and "pulling" of the tubular. It is widely applicable to production wells such as oil wells, natural gas wells, and water injection wells, providing the most basic process preparation for existing workover techniques and achieving wellbore cleaning.

[0015] The method for cleaning the inner wall of a wellbore tubular string of the present invention uses the wellbore tubular string inner wall cleaning tool described above, so it has the same beneficial effects as the wellbore tubular string inner wall cleaning tool described above, and therefore, it is not described in detail here.

[0016] Other features and advantages of the present invention will be described in the following description, and in part will become apparent from the description, or will be understood by practicing the present invention. The purpose and other advantages of the present invention can be realized and obtained by the structures pointed out in the description and the drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following is a brief introduction to the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0018] Figure 1 A schematic diagram of a wellbore tubular inner wall cleaning tool according to an embodiment of the present invention is shown; Figure 2 A schematic diagram of a cylinder in an embodiment of the present invention is shown; Figure 3 A partial expansion schematic diagram of a cylinder in an embodiment of the present invention is shown; Figure 4 shows a schematic diagram of a first piston in an embodiment of the present invention; Figure 5 shows a schematic diagram of a second piston in an embodiment of the present invention; Figure 6A schematic diagram of a tube body in an embodiment of the present invention is shown; Figure 7 A partial expansion schematic diagram of a tube body in an embodiment of the present invention is shown; Figure 8 A flow chart of a method for cleaning the inner wall of a wellbore tubular string in an embodiment of the present invention is shown.

[0019] In the figure, 100, cylinder; 110, through hole; 120, third inner boss; 130, first shear pin; 140, second shear pin; 150, thrust bearing; 200, first piston; 210, first outer boss; 300, second piston; 310, second outer boss; 320, fixing block; 400, sealing member; 500, tube body; 510, through groove; 520, isolation ring; 530, fourth inner boss. DETAILED DESCRIPTION

[0020] To make the objectives, technical solutions, and advantages of the embodiments of the present invention more clear, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts shall fall within the scope of protection of the present invention.

[0021] Reference Figure 1 and Figure 2 An embodiment of the present invention provides a tool for cleaning the inner wall of a wellbore tubular string, comprising: a cylinder 100, a first piston 200, a second piston 300 and a sealing member 400. A first channel is axially arranged in the cylinder 100, and a through hole 110 is provided on the outer periphery of the cylinder 100. The first piston 200 is movably arranged at one end of the first channel along the axial direction of the cylinder 100, and the outer wall of the first piston 200 is in contact with the inner wall of the first channel. The second piston 300 is movably arranged at the other end of the first channel along the axial direction of the cylinder 100, and the outer wall of the second piston 300 is in contact with the inner wall of the first channel. A second channel is provided in the second piston 300 along the axial direction of the cylinder 100, and the water outlet end of the second channel is arranged toward the first piston 200 and is connected to the first channel. The sealing member 400 is movably provided at the water inlet end of the second channel.

[0022] Specifically, the cylinder 100 is the main cylinder body, and the first piston 200 is movably disposed at one end of the first channel along the axial direction of the cylinder 100. The outer wall of the first piston 200 is in contact with the inner wall of the first channel. Therefore, when the outer wall of the first piston 200 coincides with the through hole 110 of the cylinder 100, the through hole 110 can be blocked by the outer wall of the first piston 200. When the cleaning fluid is delivered, the cleaning fluid can pass through the second channel of the second piston 300 and reach the first channel of the cylinder 100 through the water outlet of the second channel, thereby applying pressure to the first piston 200 and pushing the first piston 200 to move axially along the cylinder 100 until the first piston 200 is misaligned with the through hole 110 of the cylinder 100, allowing the cleaning fluid in the first channel to be ejected from the through hole 110 to clean the inner wall of the wellbore. The movement of the first piston 200 can also provide a buffer, maintaining the starting pressure during cleaning within a safe range to reduce the pressure on components. After cleaning is complete, the plugging member 400 is lowered to block the water inlet of the second channel. As the cleaning fluid continues to flow, pressure is applied to the second piston 300, pushing it axially along the cylinder 100 until the outer wall of the second piston 300 coincides with the through-hole 110. This re-blocks the through-hole 110 with the outer wall of the second piston 300, allowing the entire pipe string to be removed. The movement of the second piston 300 provides additional cushioning, further reducing the pressure on components and achieving safe removal of the pipe string.

[0023] In some specific embodiments of the present invention, referring to Figure 1 and Figure 6 The inner wall of the cylinder 100 is coaxially rotated with a tube body 500, so that the inner wall of the tube body 500 forms a first channel. A through groove 510 is opened on the outer periphery of the tube body 500. When the through hole 110 and the through groove 510 coincide with each other, the through hole 110 is connected to the first channel.

[0024] Specifically, the tube body 500 is coaxially rotatably disposed within the cylinder body 100, positioned between the inner wall of the cylinder body 100 and the outer walls of the first piston 200 and the outer walls of the second piston 300. A through-slot 510 is defined on the outer periphery of the tube body 500. When the through-hole 110 overlaps with the through-slot 510, the through-hole 110 communicates with the first channel. By driving the through-slot 510 with the tube body 500, the relative positional relationship and degree of overlap between the through-slot 510 and the through-hole 110 can be adjusted, thereby increasing the spray angle range of the cleaning fluid through the interaction between the through-slot 510 and the through-hole 110.

[0025] Furthermore, the circumferential outer wall of the tube body 500 is completely nested on the inner wall of the cylinder body 100 , so that the first channel enclosed by the inner wall of the tube body 500 can communicate with the channel in the cylinder body 100 .

[0026] Before cleaning begins, one end of the first piston 200 is inserted into the tubular body 500 from one end of the tubular body 500, and the other end of the first piston 200 is inserted out of the corresponding end of the cylindrical body 100. The outer wall of the end of the first piston 200 inserted into the tubular body 500 coincides with the through groove 510 of the tubular body 500. One end of the second piston 300 is inserted into the tubular body 500 from one end of the tubular body 500, and the other end of the second piston 300 extends toward the corresponding end of the cylindrical body 100. When the cleaning fluid starts to be transported into the second channel of the second piston 300, the cleaning fluid passes through the second channel and reaches the tube body 500 through the water outlet end of the second channel to apply pressure to the first piston 200. When the pressure in the tube body 500 reaches the first pressure value, the hydraulic pressure will push the first piston 200 to move along the axial direction of the cylinder 100 in the direction away from the second piston 300 until the outer wall of one end of the first piston 200 penetrating into the tube body 500 is misaligned with the through groove 510 of the tube body 500, thereby releasing the blockage of the through groove 510. At the same time, the hydraulic pressure will also drive the tube body 500 to rotate circumferentially relative to the cylinder body 100, so that the through groove 510 coincides with the through hole 110 of the cylinder body 100, and then the cleaning fluid in the tube body 500 can be sprayed out through the through groove 510 and the through hole 110 in sequence, thereby cleaning the inner wall of the wellbore. After the inner wall of the wellbore is cleaned, the sealing member 400 is lowered to block the water inlet end of the second channel. When the pressure at the water inlet end of the second channel reaches a second pressure value, the hydraulic pressure will push the second piston 300 to move along the axial direction of the cylinder 100 toward the first piston 200 until the outer wall of one end of the second piston 300 that penetrates into the tube body 500 coincides with the through groove 510 of the tube body 500, thereby stopping the spraying of the cleaning fluid.

[0027] Furthermore, a thread is provided on the outer wall of one end of the first piston 200 located outside the cylinder 100 to facilitate connection with other pipe string equipment.

[0028] Furthermore, a bowl-shaped fixing block 320 is sleeved onto the outer wall of the second piston 300 at the end away from the first piston 200. This bowl-shaped fixing block 320 forms a sloped surface around the water inlet of the second channel. The spherical sealing member 400, when lowered, follows the sloped surface to cover the water inlet of the second channel, thereby sealing the water inlet of the second channel.

[0029] Furthermore, the outer wall of the fixing frame is threadedly connected to the inner wall of the cylinder 100 .

[0030] In some specific embodiments of the present invention, referring to Figure 1Two thrust bearings 150 are coaxially rotatably provided on the inner wall of the cylinder 100, and the tubular body 500 is located between the two thrust bearings 150. One thrust bearing 150 is rotatably sleeved on the outer periphery of the first piston 200, and the other thrust bearing 150 is rotatably sleeved on the outer periphery of the second piston 300.

[0031] Specifically, the tubular body 500 is positioned between two thrust bearings 150, and each end of the tubular body 500 is connected to the two thrust bearings 150. Thus, the tubular body 500 can be rotated within the cylindrical body 100 via the two thrust bearings 150. One thrust bearing 150 is rotatably mounted on the outer circumference of the first piston 200, and the other thrust bearing 150 is rotatably mounted on the outer circumference of the second piston 300, thereby preventing interference with the movement of the first and second pistons 200, 300.

[0032] In some specific embodiments of the present invention, referring to Figure 1 A first external boss 210 is provided on the outer wall of the first piston 200, and a second external boss 310 is provided on the outer wall of the second piston 300. A third internal boss 120 is provided on the inner wall of the cylinder 100. When the first piston 200 moves away from the second piston 300 along the axial direction of the cylinder 100 to a first preset position, the third internal boss 120 engages with the first external boss 210. A fourth internal boss 530 is provided on the inner wall of the tube body 500. When the second piston 300 moves away from the first piston 200 along the axial direction of the cylinder 100 to a second preset position, the fourth internal boss 530 engages with the second external boss 310.

[0033] Specifically, refer to Figure 4 The first piston 200 is inserted into the outer wall of the tube body 500 and is surrounded by a first outer boss 210. The outer wall of the first outer boss 210 is in contact with the inner wall of the tube body 500, so that the through groove 510 of the tube body 500 can be blocked and unblocked by the movement of the first outer boss 210. Figure 2 The inner wall of the cylinder 100 at one end through which the first piston 200 is passed is surrounded by a third inner boss 120, and the first outer boss 210 and the third inner boss 120 overlap with each other in the axial direction of the cylinder 100. After the cleaning liquid is delivered, when the first piston 200 moves along the axial direction of the cylinder 100 away from the second piston 300 and moves to the first preset position, the third inner boss 120 and the first outer boss 210 abut against each other, thereby achieving the clamping connection between the first piston 200 and the cylinder 100, so as to prevent the first piston 200 from falling out of the cylinder 100. Figure 5 The outer wall of one end of the second piston 300 that passes through the tube body 500 is surrounded by a second outer boss 310. The outer wall of the second outer boss 310 fits in contact with the inner wall of the tube body 500, so that the through groove 510 of the tube body 500 can be blocked and unblocked by moving the second outer boss 310. Figure 6 A fourth inner boss 530 is arranged around the inner wall of the tube body 500 at one end through which the first piston 200 is passed. The fourth inner boss 530 is located on the side of the second outer boss 310 away from the first piston 200, and the second outer boss 310 and the fourth inner boss 530 overlap with each other in the axial direction of the cylinder body 100. When the second piston 300 moves along the axial direction of the cylinder body 100 away from the second piston 300 and moves to the second preset position, the fourth inner boss 530 and the second outer boss 310 abut against each other, thereby realizing the clamping connection between the second piston 300 and the tube body 500 to prevent the second piston 300 from falling out of the tube body 500.

[0034] Furthermore, an annular groove is provided around the outer wall of the first outer boss 210 , and a sealing ring is embedded in the annular groove to ensure a sealing effect.

[0035] Furthermore, the first piston 200, the second piston 300, the cylinder 100 and the tube 500 are all made of 35CrMo in a quenched and tempered state, and the final heat treatment state is 200HB to 250HB.

[0036] Furthermore, one of the thrust bearings 150 is located on the side of the third inner boss 120 close to the first outer boss 210, allowing the first piston 200 to abut against the third inner boss 120 via the thrust bearing 150. The other thrust bearing 150 is located at the end of the tubular body 500 away from the third inner boss 120, and a limiting pin is provided on the inner wall of the cylinder 100 on the side of the thrust bearing 150 away from the tubular body 500. This allows the two thrust bearings 150 and the tubular body 500 to be constrained between the limiting pin and the third inner boss 120, thereby preventing the tubular body 500 from moving axially along the cylinder 100.

[0037] Furthermore, the models of the two thrust bearings 150 are both 51305.

[0038] In some specific embodiments of the present invention, referring to Figure 1 The first piston 200 is connected to the cylinder 100 via a first shear pin 130. The second piston 300 is connected to the cylinder 100 via a second shear pin 140. When the axial pressure on the first piston 200 in the cylinder 100 reaches a first pressure value, the first shear pin 130 breaks. When the axial pressure on the second piston 300 in the cylinder 100 reaches a second pressure value, the second shear pin 140 breaks.

[0039] Specifically, before cleaning begins, a first shear pin 130 is threadedly inserted between the third inner boss 120 and the outer wall of the first piston 200, thereby securing the connection between the first piston 200 and the cylinder 100. When the pressure on the first piston 200 reaches a first pressure value, the first shear pin 130 breaks, thereby enabling the movement of the first piston 200. Before cleaning begins, a second shear pin 140 is threadedly inserted between the end of the cylinder 100 away from the first piston 200 and the outer wall of the fixed block 320, thereby securing the connection. When the pressure on the second piston 300 reaches a second pressure value, the second shear pin 140 breaks, thereby enabling the movement of the second piston 300. The provision of the first and second shear pins 130, 140 facilitates maintaining pressure within a safe range.

[0040] Furthermore, at least two first shear pins 130 and second shear pins 140 are provided, and are symmetrically arranged with respect to the axial direction of the cylinder 100 .

[0041] Furthermore, the first shear pin 130 and the second shear pin 140 are made of brass.

[0042] In some specific embodiments of the present invention, referring to Figure 3 and Figure 7 Multiple groups of through holes 110 are provided, and each group of through holes 110 includes multiple through holes 110. The multiple groups of through holes 110 are evenly arranged along the circumference of the cylinder 100, and the multiple through holes 110 in each group of through holes 110 are evenly arranged along the axial direction of the cylinder 100. Multiple groups of through grooves 510 are provided, and each group of through grooves 510 includes multiple through grooves 510. The multiple groups of through grooves 510 are evenly arranged along the axial direction of the cylinder 100, and the multiple through grooves 510 in each group of through grooves 510 are evenly arranged along the circumference of the cylinder 100.

[0043] Specifically, the multiple groups of through holes 110 are evenly arranged along the circumference of the barrel 100, and the multiple through holes 110 within each group of through holes 110 are evenly arranged along the axial direction of the barrel 100. The multiple groups of through grooves 510 are evenly arranged along the axial direction of the barrel 100, and the multiple through grooves 510 within each group of through grooves 510 are evenly arranged along the circumference of the barrel 100. This can further expand the spray angle range of the cleaning fluid to ensure the cleaning effect on the inner wall of the wellbore.

[0044] In some specific embodiments of the present invention, referring to Figure 3 The multiple groups of through holes 110 are staggered along the axial direction of the cylinder 100.

[0045] Specifically, the multiple through holes 110 in the multiple groups of through holes 110 are arranged in a one-to-one correspondence, and there is a phase difference of 20 degrees between the two corresponding through holes 110 in two adjacent groups of through holes 110, so that the multiple through holes 110 in the multiple groups of through holes 110 are staggered with each other, which can further expand the spray angle range of the cleaning fluid to ensure the cleaning effect of the inner wall of the wellbore.

[0046] In some specific embodiments of the present invention, referring to Figure 6 A plurality of isolation rings 520 are disposed around the outer wall of the tube body 500. An isolation zone is formed between two adjacent isolation rings 520. The plurality of isolation zones correspond to the plurality of through grooves 510 in a one-to-one manner.

[0047] Specifically, the isolation ring 520 is disposed around the outer wall of the tube body 500, so that the outer wall of the tube body 500 can abut against the inner wall of the cylinder 100 through the isolation ring 520. There are multiple isolation rings 520, and the multiple isolation rings 520 are evenly arranged along the axial direction of the cylinder 100, and an isolation zone is formed between each adjacent two isolation rings 520, and multiple isolation zones are formed by the multiple isolation rings 520. The multiple isolation zones correspond one-to-one to the multiple groups of through grooves 510, so that the multiple through grooves 510 in each group of through grooves 510 are all located in the isolation zone enclosed by the corresponding two isolation rings 520, so as to ensure the sealing between the cylinder 100 and the tube body 500, so that the cleaning liquid passing through the through grooves 510 can be accurately sprayed out from the through hole 110.

[0048] In some specific embodiments of the present invention, referring to Figure 2 and Figure 3 The angle between the center line of the through hole 110 and the axis of the cylinder 100 is in the range of 40 to 50 degrees. Figure 6 and Figure 7 The angle between the connecting line between the two ends of the through groove 510 and the axis of the cylinder 100 ranges from 40 degrees to 50 degrees.

[0049] Specifically, the angle range between the center line of the through hole 110 and the axis of the cylinder 100 is 45 degrees, and the angle range between the connecting line between the two ends of the through groove 510 and the axis of the cylinder 100 is 45 degrees, which can further expand the spray angle range of the cleaning fluid to ensure the cleaning effect of the inner wall of the wellbore.

[0050] In some specific embodiments of the present invention, the first piston 200 has a length of 300 mm and a diameter of 30 mm. The first external boss 210 has a length of 60.76 mm and an outer diameter of 40 mm. The diameter of the sealing ring is 36.3 x 1.78 mm. The thread size of the first shear pin 130 is M5 x 0.8 mm and the length is 20 mm. The thread size of the second shear pin 140 is M5 x 1 mm and the length is 7.75 mm. The length of the cylinder 100 is 410 mm. The length of the third internal boss 120 is 40 mm. The wall thickness of the cylinder 100 where the third internal boss 120 is not provided is 6.02 mm. The diameter of the through hole 110 is 10 mm. The length of the tube 500 is 232.06 mm and the inner diameter is 40 mm. The length of the fourth internal boss 530 is 33 mm and the inner diameter is 25 mm. The outer diameter of the isolation ring 520 is 51.96 mm. Three isolation rings 520 are provided, and the distance between the three isolation rings 520 and the end of the tube body 500 away from the fourth inner boss 530 is 60.44 mm, and the distance between two adjacent isolation rings 520 is 30.38 mm. The length of the through groove 510 is 21.47 mm and the diameter is 5 mm. The length of the second piston 300 is 201 mm and the inner diameter is 15 mm. The outer diameter of the second outer boss 310 is 40 mm and the length is 60 mm. The length of the limit pin is 10 mm. The length of the fixing block 320 is 18.87 mm, and the angle of the slope surface is 123.41 degrees.

[0051] Reference Figure 8 The embodiment of the present invention further provides a method for cleaning the inner wall of a wellbore pipe string, which uses the wellbore pipe string inner wall cleaning tool as described in any of the above specific embodiments, including the following steps: lowering the wellbore pipe string inner wall cleaning tool into the wellbore to the position to be cleaned; delivering cleaning fluid into the second channel of the second piston 300, the cleaning fluid passes through the second channel and reaches the first channel of the cylinder 100 through the water outlet end of the second channel, applying pressure to the first piston 200 and pushing the first piston 200 to move axially along the cylinder 100. The first piston 200 is moved until the through hole 110 of the cylinder 100 is misaligned, so that the through hole 110 is connected to the first channel; the cleaning liquid is continuously delivered so that the cleaning liquid is sprayed out from the through hole 110 to clean the inner wall of the wellbore; after the cleaning is completed, the blocking member 400 is lowered to block the water inlet end of the second channel, and the cleaning liquid is continuously delivered to apply pressure to the second piston 300 and push the second piston 300 to move axially along the cylinder 100 until the second piston 300 coincides with the through hole 110, thereby blocking the through hole 110.

[0052] The first piston 200, once the cleaning fluid enters the first channel, applies pressure to the first piston 200 and propels it axially along the cylinder 100. This movement of the first piston 200 provides a buffer, maintaining the starting pressure during cleaning within a safe range and reducing the pressure on components. Once cleaning is complete, the second piston 300 moves to seal the through hole 110, halting cleaning. The second piston 300 then moves again to provide a buffer, further reducing the pressure on components and achieving safe removal of the tubular string.

[0053] Since the method for cleaning the inner wall of a wellbore tubular string adopts the wellbore tubular string inner wall cleaning tool described in any of the above specific embodiments, it has the same beneficial effects as the wellbore tubular string inner wall cleaning tool described above, and therefore, it is not described in detail here.

[0054] Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein; and these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A wellbore tubular inner wall cleaning tool, characterized in that: include: A cylinder (100), wherein a first passage is provided in the cylinder (100) along the axial direction, and a through hole (110) is provided on the outer periphery of the cylinder (100); a first piston (200), the first piston (200) being movably disposed at one end of the first channel along the axial direction of the tube body (500) of the cylinder (100), and the outer wall of the first piston (200) being in contact with the inner wall of the first channel; a second piston (300), the second piston (300) being movably disposed at the other end of the first channel along the axial direction of the cylinder (100), and the outer wall of the second piston (300) being in contact with the inner wall of the first channel; A second channel is provided in the second piston (300) along the axial direction of the cylinder (100), and a water outlet end of the second channel is arranged toward the first piston (200) and communicates with the first channel; A blocking member (400) is movably disposed at the water inlet end of the second channel.

2. The wellbore tubular inner wall cleaning tool according to claim 1, characterized in that: A tube body (500) is coaxially rotatably provided on the inner wall of the cylinder (100), so that the inner wall of the tube body (500) encloses the first channel; A through groove (510) is provided on the outer periphery of the tube body (500); when the through hole (110) and the through groove (510) coincide with each other, the through hole (110) is in communication with the first channel.

3. The wellbore tubular inner wall cleaning tool according to claim 2, characterized in that: Two thrust bearings (150) are coaxially rotatably provided on the inner wall of the cylinder (100), and the tube (500) is located between the two thrust bearings (150); One of the thrust bearings (150) is rotatably sleeved on the outer periphery of the first piston (200), and the other thrust bearing (150) is rotatably sleeved on the outer periphery of the second piston (300).

4. The wellbore tubular inner wall cleaning tool according to claim 2, characterized in that: A first external boss (210) is provided on the outer wall of the first piston (200), and a second external boss (310) is provided on the outer wall of the second piston (300); A third inner boss (120) is provided on the inner wall of the cylinder (100), and when the first piston (200) moves away from the second piston (300) to a first preset position along the axial direction of the cylinder (100), the third inner boss (120) is engaged with the first outer boss (210); A fourth inner boss (530) is provided on the inner wall of the tube body (500). When the second piston (300) moves away from the first piston (200) to a second preset position along the axial direction of the cylinder body (100), the fourth inner boss (530) is engaged with the second outer boss (310).

5. The wellbore tubular inner wall cleaning tool according to claim 2, characterized in that: The first piston (200) is connected to the cylinder (100) via a first shear pin (130); The second piston (300) is connected to the cylinder (100) via a second shear pin (140); When the pressure exerted on the first piston (200) in the axial direction of the cylinder (100) reaches a first pressure value, the first shear pin (130) breaks; When the pressure exerted on the second piston (300) in the axial direction of the cylinder (100) reaches a second pressure value, the second shear pin (140) breaks.

6. The wellbore tubular inner wall cleaning tool according to claim 2, characterized in that: The through holes (110) are provided in a plurality of groups, and each group of the through holes (110) includes a plurality of the through holes (110); The plurality of groups of through holes (110) are evenly arranged along the circumference of the cylinder (100), and the plurality of through holes (110) in each group of through holes (110) are evenly arranged along the axial direction of the cylinder (100); The through slots (510) are provided in a plurality of groups, and each group of the through slots (510) includes a plurality of the through slots (510); The plurality of groups of through grooves (510) are evenly arranged along the axial direction of the cylinder (100), and the plurality of through grooves (510) in each group of through grooves (510) are evenly arranged along the circumference of the cylinder (100).

7. The wellbore tubular inner wall cleaning tool according to claim 6, characterized in that: The plurality of groups of through holes (110) are staggered along the axial direction of the cylinder (100).

8. The wellbore tubular inner wall cleaning tool according to claim 6, characterized in that: A plurality of isolation rings (520) are arranged around the outer wall of the tube body (500); An isolation zone is formed between two adjacent isolation rings (520); There is a one-to-one correspondence between the plurality of isolation zones and the plurality of groups of through slots (510).

9. The wellbore tubular inner wall cleaning tool according to claim 2, characterized in that: The angle between the center line of the through hole (110) and the axis of the cylinder (100) ranges from 40 degrees to 50 degrees; The included angle between the end connecting line of the through groove (510) and the axis of the cylinder (100) ranges from 40 degrees to 50 degrees.

10. A method for cleaning the inner wall of a wellbore tubular string, using the wellbore tubular string inner wall cleaning tool according to any one of claims 1 to 9, characterized in that: The following steps are involved: Lower the wellbore tubing inner wall cleaning tool into the wellbore to the position to be cleaned; The cleaning liquid is transported into the second channel of the second piston (300), and the cleaning liquid passes through the second channel and reaches the first channel in the cylinder (100) through the water outlet of the second channel, exerting pressure on the first piston (200) and pushing the first piston (200) to move along the axial direction of the cylinder (100) until the first piston (200) and the through hole (110) of the cylinder (100) are misaligned, so that the through hole (110) is connected to the first channel; Continuously delivering the cleaning fluid so that the cleaning fluid is ejected from the through hole (110) to clean the inner wall of the wellbore; After cleaning is completed, the blocking member (400) is lowered to block the water inlet end of the second channel, and the cleaning liquid is continued to be delivered to apply pressure to the second piston (300) and push the second piston (300) to move along the axial direction of the cylinder (100) until the second piston (300) coincides with the through hole (110), thereby blocking the through hole (110).

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