Combined type shaft cleaning drilling tool assembly

Abstract

The utility model relates to the technical field of oil and gas exploitation downhole tools, and particularly discloses a combined type shaft cleaning drilling tool assembly which comprises at least one middle short section and a flushing short section, and the at least one flushing short section is located below the lowest middle short section. Cleaning nozzles distributed in the circumferential direction of the middle short section are arranged on the middle short section; the flushing short section comprises a short section main body and a rotating sleeve which is installed on the short section main body in a rotatable mode, a brush body structure is arranged on the outer portion of the rotating sleeve, and the rotating sleeve is provided with a hydraulic drive rotating structure. By the adoption of the scheme, the requirements for cleaning of wax dirt on the inner wall of a shaft and cleaning of well bottom settled sand can be met, the cleaning effect on the shaft can be further improved by adding the flushing short section, the operation period is shortened, the well opening time is shortened, and the underground operation risk is reduced.

Description

Technical Field

[0001] This utility model relates to the field of downhole tools technology for oil and gas extraction, specifically to a composite wellbore cleaning drill string assembly. Background Technology

[0002] In the later stages of oil well production, phenomena such as sand production at the bottom of the well and wax deposition on the wellbore often occur due to factors such as decreased formation pressure, changes in fluid properties, and aging of the wellbore structure. These phenomena severely impact the overall production performance and oil and gas recovery rate of the oil well. After sand production, if the fluid flow in the well cannot carry all the sand to the surface, the sand gradually settles, forming sand columns that block the oil production channels, increase flow resistance, and cause reduced or even halted production. Simultaneously, sand production also causes wear and damage to downhole equipment, increasing maintenance costs and even triggering downhole sand jams, endangering personnel safety. On the other hand, wax deposition inside oil wells is very common, especially during the extraction of waxy crude oil. Due to the decrease in formation pressure and temperature, wax components in the crude oil precipitate or dissolve, forming crystals or colloids that are adsorbed or deposited on equipment. These wax deposits affect equipment operating efficiency, increase production costs, and may even cause equipment damage or wellbore blockage.

[0003] To address these issues, regular wax removal and sand flushing are crucial for improving oil well production efficiency and extending well lifespan. However, currently, there are no efficient, integrated tools for wax removal and well flushing, forcing each trip of the tubing string to be performed as a single operation. This severely impacts operational efficiency, construction time, and well workover costs. Particularly during wax removal, the dispersed wax flushed from the lower section easily adheres to the wellbore wall during the upward return process, reducing the wax removal effect. Therefore, the applicant previously filed a patent application (CN119163385B) entitled "Combination of Cleaning Tools and Method for Oil and Gas Wellbore," which utilizes the combination of end and middle short sections to maximize the cleaning of the wellbore wall, avoiding or reducing missed areas, thereby improving the wax removal and descaling effect while simultaneously meeting sand flushing requirements. However, further field practice revealed that using nozzle rotation for cleaning still leaves blind spots, failing to achieve optimal cleaning results and limiting the drilling speed during lowering and raising, extending operation time and increasing overall operating costs and risks. Utility Model Content

[0004] In view of this, the present invention provides a composite wellbore cleaning drill bit assembly, which aims to solve the technical problems of poor wellbore cleaning effect and long operation cycle in current oil and gas production wells.

[0005] To achieve the above objectives, the technical solution of this utility model is as follows.

[0006] A composite wellbore cleaning drill string assembly includes at least one intermediate sub and a cleaning sub, wherein at least one cleaning sub is located below the lowest intermediate sub.

[0007] The intermediate short section has cleaning nozzles distributed circumferentially thereon.

[0008] The cleaning section includes a section body and a rotating sleeve rotatably mounted on the section body. The rotating sleeve has a brush body structure on its exterior and a hydraulically driven rotation structure.

[0009] Using the above scheme, when the well-washing fluid is pumped in from the top of the drill string assembly, it can be sprayed out through the cleaning nozzle to jet-clean the well wall. At the same time, the well-washing fluid drives the rotating sleeve to rotate through the hydraulic drive structure, and the brush structure brushes the well wall.

[0010] The system primarily utilizes a combination of a cleaning sub and an intermediate sub. The bottom cleaning sub removes most of the surface wax deposits from the wellbore wall, while the upper intermediate sub performs a rotary cleaning action, directly targeting deep-seated, stubborn wax deposits. The upper cleaning sub circulates throughout the wellbore during the cleaning process, effectively preventing the wax removed from the lower section from re-adhering to the wall. This combination of cleaning methods significantly improves the cleaning effect. Furthermore, when used alone, the intermediate sub's nozzle position limits its raising and lowering speeds. However, in this system, the combination with the cleaning sub ensures comprehensive cleaning of the wellbore's inner wall, reducing missed areas. This allows for faster drill string lowering and raising during the circulation process, thereby shortening the work cycle and reducing operational risks.

[0011] Preferably, the upper and lower ends of the short section body have screw-connected parts, the upper part of the short section body has an upper hollow section with an opening facing upwards, the lower part has a lower hollow section with an opening facing downwards, the middle part of the short section body is a solid body, the side wall of the upper hollow section is provided with a liquid outlet, and the side wall of the lower hollow section is provided with a liquid inlet.

[0012] The inner wall of the rotating sleeve and the main body of the short section have a gap, which forms an annulus in the short section. The hydraulic drive structure includes a helical blade structure disposed on the inner wall of the rotating sleeve. This design ensures unobstructed flow and sufficient pressure at the bottom of the well.

[0013] Preferably, the assembly also includes an end section located at the lower end of the drill string assembly, with the vertical distance between the lowest cleaning end section and the end section being less than 100 meters. Using this configuration, the end section can perform a primary cleaning of the wellbore, further enhancing the cleaning effect, while the flushing effect of the end section can be fully consolidated within this vertical distance range.

[0014] Preferably, the cleaning short sections are arranged in pairs, or in pairs with the middle short sections. Using these two arrangements, the re-adhesion of the removed wax residue can be effectively prevented, thus ensuring a stable cleaning effect.

[0015] Preferably, the outer wall of the rotating sleeve has a helical channel, with open ends at both the top and bottom. When fluid enters the helical channel from bottom to top, the rotation direction of the rotating sleeve is the same as the rotation direction driven by the fluid impacting the helical blade structure from top to bottom. Using this design, when the fluid in the wellbore annulus circulates upwards, it can also drive the rotating sleeve to rotate. This combined internal and external action increases the rotational speed of the rotating sleeve and reduces pressure loss.

[0016] Preferably, there are at least three spiral channels, evenly distributed along the circumference of the rotating sleeve. This design improves the stability of the rotating sleeve during rotation.

[0017] Preferably, a spiral boss is formed between the spiral channels, and the brush body structure is disposed on the spiral boss.

[0018] Preferably, the lower part of the short section body has an anti-detachment step, the outer diameter of which is larger than the inner diameter of the rotating sleeve. This design prevents the rotating sleeve from falling directly to the bottom of the well after it becomes loose, reducing the risk of fish falling into the well.

[0019] Preferably, the spiral blade structure is a continuous spiral blade or an impeller structure.

[0020] Preferably, the cleaning nozzle is rotatably mounted on the intermediate short section and has at least three spiral water holes inside. This design increases the cleaning nozzle's coverage area, further improving the cleaning efficiency of the drill string assembly.

[0021] Compared with the prior art, the beneficial effects of this utility model are:

[0022] The composite wellbore cleaning drill bit assembly provided by this utility model can meet the cleaning needs of wellbore inner wall such as wax scale and bottom sand. Adding a cleaning sub can further improve the cleaning effect of the wellbore, shorten the operation cycle, that is, shorten the well opening time and reduce the risk of downhole operation. Attached Figure Description

[0023] Figure 1 A schematic diagram of the cleaning short section structure;

[0024] Figure 2 for Figure 1 A sectional view;

[0025] Figure 3 This is a schematic diagram of the rotating sleeve structure;

[0026] Figure 4 for Figure 3 Internal structure diagram;

[0027] Figure 5 for Figure 3 A sectional view;

[0028] Figure 6 This is a second embodiment of the helical blade structure;

[0029] Figure 7 This is a schematic diagram of the end section structure;

[0030] Figure 8 for Figure 7 Exploded view;

[0031] Figure 9 for Figure 7 A cross-sectional view (the sliding sleeve fluid channel is in the open state).

[0032] Figure 10 for Figure 7 A cross-sectional view (the sliding sleeve fluid channel is blocked).

[0033] Figure 11 This is a schematic diagram of the sliding sleeve structure;

[0034] Figure 12 This is a schematic diagram of the middle short section structure;

[0035] Figure 13 A cross-sectional view of an installation structure for a cleaning nozzle;

[0036] Figure 14 A schematic diagram showing the distribution of nozzle mounting holes C;

[0037] Figure 15 Perspective view of the cleaning nozzle;

[0038] Figure 16 This is a schematic diagram of one embodiment of the present invention in use.

[0039] In the diagram: 100, end section; 110, nozzle mounting hole A; 111, main nozzle; 112, secondary nozzle; 120, nozzle mounting hole B; 130, first section; 131, upper guide channel; 132, pin hole; 133, receiving cavity; 134, shear pin; 140, second section; 141, lower guide channel; 200, middle section; 210, nozzle mounting hole C; 300, cleaning nozzle; 310, spiral water eye; 400, sliding sleeve; 410, main body; 411, ball seat; 412, annular groove; 413, sealing groove; 420. Limiting part; 421. Disc-shaped body; 422. Lobe-shaped body; 430. Fluid guiding channel; 500. Steel ball; 600. Bearing; 700. Oil tubing string; 800. Cleaning stub; 810. Upper hollow section; 811. Liquid outlet; 820. Lower hollow section; 821. Liquid inlet; 830. Rotating sleeve; 831. Brush body structure; 832. Spiral blade structure; 833. Spiral channel; 834. Spiral boss; 840. Stub annulus; 850. Support bearing; 860. Connecting ring; 870. Anti-detachment step; 880. Stub body. Detailed Implementation

[0040] The present invention will be further described below with reference to the embodiments and accompanying drawings.

[0041] refer to Figures 1 to 16 The composite wellbore cleaning drill assembly shown includes at least one intermediate section 200. The structure of this intermediate section is the same as that of the intermediate section in the applicant's previous patent number "CN119163385B" entitled "Wellbore Cleaning Tool Assembly and Cleaning Method for Oil and Gas Wells". The key point of this application is that the drill assembly also includes a cleaning section 800 and the position design of the cleaning section. At least one cleaning section 800 is located below the lowest intermediate section 200, and the intermediate section 200 has cleaning nozzles 300 distributed along its circumference.

[0042] like Figures 1 to 6 As shown, the cleaning section 800 mainly includes a section body 880 and a rotating sleeve 830 rotatably mounted on the section body 880. The rotating sleeve 830 has a brush body structure 831 on its exterior and a hydraulically driven structure.

[0043] Specifically, the short section body 880 has a rotating structure. The upper and lower ends of the short section body 880 (Note: in this application, the upper and lower direction is based on its usage state, with the end closer to the bottom of the well being the lower end, and vice versa, the end closer to the wellhead being the upper end) have threaded connection parts, which can be quickly connected to the upper and lower drilling tools through the threaded connection parts. The upper part of the short section body 880 has an upper hollow section 810 with an open opening facing upwards, and the lower part has a lower hollow section 820 with an open opening facing downwards. The middle part of the short section body 880 is a solid body. The side wall of the upper hollow section 810 is provided with a liquid outlet 811, and the side wall of the lower hollow section 820 is provided with a liquid inlet 821.

[0044] The rotating sleeve 830 is coaxially arranged with the short section body 880 and located circumferentially outside the short section body 880. The outer surface of the rotating sleeve 830 has a brush structure 831. The inner diameter of the rotating sleeve 830 is larger than the outer diameter of the short section body 880, and there is a gap between its inner wall and the short section body 880, which forms the short section annulus 840. The hydraulic drive structure includes a helical blade structure 832 disposed on the inner wall of the rotating sleeve 830. The helical blade structure 832 can be, for example, Figure 6 The impeller structure shown can be configured with multiple impellers arranged axially on the rotating sleeve 830. Alternatively, a similar impeller structure can be used. Figure 4 and Figure 5 The continuous helical blades shown can drive the rotating sleeve 830 to rotate when the fluid impacts. The inner diameter of the helical blade structure 832 is slightly larger than the outer diameter of the short section body 880, ensuring that the fluid passes through the helical blade structure 832 in the short section annulus 840 and generates thrust on it.

[0045] In use, the sub is connected to the drill string assembly. The circulating fluid injected from the ground enters through the drill string from the top of the upper hollow section 810, and then enters the annulus 840 of the sub through the outlet 811. The fluid impacts the spiral blade structure 832, causing the rotating sleeve 830 to rotate. Finally, the fluid enters the lower hollow section 820 through the inlet 821, and then returns to the lower drill string. The impact force of the fluid drives the rotating sleeve to rotate, and the external brush structure cleans the wax scale on the wellbore wall.

[0046] In this application, the axial load of the drill bit is mainly borne by the short section body 880, so it is made of steel. The main function of the rotating sleeve 830 is to drive the brush body structure 831 to rotate, so a lightweight and wear-resistant alloy material is preferred in implementation.

[0047] In specific implementation, the hydraulically driven structure also includes a helical channel 833 on the outer wall of the rotating sleeve 830. The upper and lower ends of the helical channel 833 are open. It should be noted that when the fluid enters the helical channel 833 from bottom to top, the rotation direction of the rotating sleeve 830 is the same as the rotation direction of the rotating sleeve 830 caused by the fluid impacting the helical blade structure 832 from top to bottom. Therefore, the rotation direction of the helical channel 833 needs to be referenced when setting the rotation direction of the helical blade structure 832. In this embodiment, there are at least three helical channels 833, which are evenly distributed along the circumference of the rotating sleeve 830. During manufacturing, the helical channels 833 and the rotating sleeve 830 are integrally formed, and the helical blade structure 832 can be fixed inside the rotating sleeve 830 by welding.

[0048] like Figure 1 and Figure 3 As shown, a spiral boss 834 is formed between two adjacent spiral channels 833, and a brush body structure 831 is disposed on the spiral boss 834. The outer diameter of the brush body structure 831 is slightly larger than the inner diameter of the well barrel to be cleaned. In specific implementation, the brush body structure 831 can be a plate brush or a single-clump bristle planting structure. The plate brush can be directly installed on the spiral boss 834 with screws, which is convenient for quick replacement later. In order to reduce the wear of the pipe wall, the material of the bristles is usually preferably polyester fiber or abrasive nylon filaments.

[0049] refer to Figure 2 The upper and lower ends of the short section body 880 are fitted with support bearings 850, and the upper and lower ends of the rotating sleeve 830 are fixedly connected to the outer sleeves of the corresponding support bearings 850. In specific implementation, a connecting ring 860 is provided between the rotating sleeve 830 and the support bearings 850, and at least the lower connecting ring 860 has a rotational sealing structure with the short section body 880. As shown in the figure, the connecting ring 860 has a stepped interior, including a large-diameter section and a small-diameter section. The large-diameter section is adapted to the outer diameter of the support bearing 850 and is fixedly connected to the corresponding support bearing 850. The two are either interference-fitted or fastened with screws. The small-diameter section of the connecting ring 860 is adapted to the outer diameter of the short section body 880. During installation, a sealing ring can be fitted onto the corresponding position of the short section body 880 to achieve a gap seal between the connecting ring and the short section body 880. The connecting ring 860 and the rotating sleeve 830 can be fixed together by a threaded connection. The flow direction of the fluid inside the cleaning short section 800 is as follows... Figure 2 As indicated by the middle arrow.

[0050] In this embodiment, the support bearing 850 is a thrust bearing, thereby improving its axial support capacity and extending its service life.

[0051] In addition, the lower part of the short section body 880 has an anti-detachment step 870, such as Figure 1 and Figure 2 As shown, the outer diameter of the anti-detachment step 870 is larger than the inner diameter of the rotating sleeve 830. This means that even if the connection between the rotating sleeve 830 and the connecting ring 860 or the support bearing 850 fails and breaks, it will not fall directly to the bottom of the well due to the stop provided by the anti-detachment step 870, thus effectively improving the safety of the tool.

[0052] In the specific implementation process, the drill string assembly also includes an end section 100 located at the lower end of the drill string assembly. The structure and usage of the end section 100 are the same as those in the patent "CN119163385B" entitled "Oil and Gas Wellbore Cleaning Tool Assembly and Cleaning Method Thereof". The vertical distance between the lowest cleaning section 800 and the end section 100 is less than 100 meters. This vertical distance is preferred, mainly because for shallow wells, when the original well depth is shallow, a sudden drop in temperature can easily cause the wax flushed out by the end section 100 to adhere to the pipe wall again.

[0053] In addition to at least one cleaning sub 800 located between the end sub 100 and the middle sub 200, multiple cleaning sub 800s can also be spaced apart above the middle sub 200. Alternatively, cleaning sub 800s and middle sub 200s can be spaced in pairs to enhance the overall well cleaning effect. However, considering cost, a cleaning sub 800 can be placed only in the middle of the area between the end sub 100 and the middle sub 200, and another cleaning sub 800 can be placed 100-200 meters above the middle sub 200. The subs are connected using tubing strings 700 and adapters.

[0054] During use, the pumped-in well-washing fluid drives the rotating sleeve 830 to rotate, and the external brush structure 831 cleans the wax scale on the well casing wall. During the process of the well-washing fluid returning from the well casing annulus, it can also drive the rotating sleeve 830 to rotate. That is to say, during the circulation of the well-washing fluid, whether it is entering from the top of the drill string assembly and flowing to the bottom of the well, or returning from the bottom of the well to the wellhead through the annulus, the well-washing fluid can apply rotational power to the rotating sleeve 830, which can work continuously and is conducive to improving cleaning efficiency and quality.

[0055] For ease of understanding, this application provides a more detailed description of the structure of the end section 100 and the intermediate section 200, with particular reference to... Figures 7 to 15 Both ends of the end section 100 and the middle section 200 are open and have threaded joints, which can be quickly connected to the tubing for well insertion.

[0056] The end section 100 has a nozzle mounting hole A110 facing downward at its bottom and a nozzle mounting hole B120 on its side wall. The nozzle mounting holes B120 are evenly distributed around the circumference of the end section 100. Both the nozzle mounting holes A110 and B120 are connected to the inner cavity of the end section 100 and are mainly used to install their respective compatible nozzles to form a jet flow, thereby cleaning the wellbore.

[0057] The side wall of the intermediate short section 200 has a nozzle mounting hole C210 communicating with its hollow inner cavity. The nozzle mounting hole C210 is evenly distributed along the circumference of the intermediate short section 200, and a cleaning nozzle 300 is rotatably mounted in the nozzle mounting hole C210. ​​The cleaning nozzle 300 has at least three spiral water eyes 310, which are evenly distributed along the axis of the cleaning nozzle 300.

[0058] For details, please refer to the following: Figure 7 , Figure 9 and Figure 10 The lower end face of the end section 100 is generally spherical. The nozzle mounting hole A110 includes a main nozzle 111 and N auxiliary nozzles 112. The axis of the main nozzle 111 coincides with the axis of the end section 100 and corresponds to the lowest position of the end face of the end section 100. The N auxiliary nozzles 112 are evenly distributed on the circumferential outer side of the main nozzle 111 and are inclined outward. That is, the lower end of the auxiliary nozzle 112 is farther away from the axis of the end section 100 than the upper end. In specific implementation, the angle between the axis of the auxiliary nozzle 112 and the axis of the end section 100 is between 5° and 15°.

[0059] In another embodiment, in order to make the nozzle installed in the nozzle mounting hole A110 more suitable for sand flushing operations, the diameter of the main nozzle 111 is larger than the diameter of the secondary nozzle 112. In this way, the jet stream ejected from the nozzle in the main nozzle 111 has a larger relative impact force and flow rate, which can achieve a better sand flushing effect.

[0060] like Figure 7 and Figure 8 As shown, in this embodiment, the nozzle mounting holes B120 are evenly distributed along the axis of the end section 100. Specifically, the nozzle mounting holes B120 are distributed in a sinusoidal pattern on the end section 100, and adjacent nozzle mounting holes B120 have fixed axial and circumferential spacing.

[0061] In this application, to complement the flushing effect within the nozzle mounting hole A110, the nozzle mounting hole B120 is inclined toward the upper end of the end section 100, meaning the upper end of the nozzle mounting hole B120 is further away from the axis of the end section 100 than the lower end. Typically, the angle between the axis of the nozzle mounting hole B120 and the axis of the end section 100 is between 20° and 50°, which can apply roughly opposite impact forces to the deposits on the inner wall of the well, thus improving the cleaning effect.

[0062] In another embodiment, to further improve the tool's applicability and achieve better bottom sand flushing or wellbore inner wall scouring effects, the end section 100 is also used in conjunction with the sliding sleeve 400, such as... Figures 8 to 13 As shown, the sliding sleeve 400 includes a tubular body 410 and a limiting part 420 formed at the lower end of the body 410. The sliding sleeve 400 has a liquid guiding channel 430 inside.

[0063] The end section 100 is a split structure, mainly consisting of a first section 130 and a second section 140 connected as one unit. In this embodiment, the first section 130 and the second section 140 are connected as one unit by a threaded joint. The nozzle mounting hole B120 and the nozzle mounting hole A110 are located on the first section 130 and the second section 140, respectively. The first section 130 has an upper guide channel 131 adapted to the main body 410. The outer diameter of the limiting part 420 is larger than the diameter of the upper guide channel 131. The second section 140 has a lower guide channel 141 adapted to the limiting part 420.

[0064] like Figure 8 , Figure 9 and Figure 13 As shown, the first short section 130 has a pin hole 132 on its side wall, while the upper side wall of the main body 410 has an annular groove 412. In the initial state, the sliding sleeve 400 is installed in the first short section 130 by a shear pin 134. The shear pin passes through the pin hole 132 and extends into the annular groove 412, providing axial fixation for the sliding sleeve 400. The pin hole 132 is located above the nozzle mounting hole B120, and the main body 410 corresponds to the position of the nozzle mounting hole B120, thus blocking the nozzle mounting hole B120. At this time, fluid cannot be ejected through the nozzle of the nozzle mounting hole B120. A sealing groove 413 is provided on the main body 410 below the annular groove 412. During installation, a sealing ring is fitted to improve the sealing between it and the upper guide channel 131.

[0065] To further improve the installation effect of the sliding sleeve 400, a receiving cavity 133 adapted to the limiting part 420 is provided near the lower end of the first short section 130, such as... Figures 9 to 11As shown, the receiving cavity 133 communicates with the upper guide channel 131. When the sliding sleeve 400 is in its initial state, the limiting part 420 can be completely housed within the receiving cavity 133, without hindering the transportation or relocation of the first short section 130, or its connection operation with the second short section 140, while also avoiding damage to the sliding sleeve 400. Furthermore, in this embodiment, the lower end of the first short section 130 adopts a male snap-fit ​​structure, while the upper end of the second short section 140 adopts a female snap-fit ​​structure, which further prevents collisions with the sliding sleeve 400 during the connection process.

[0066] like Figure 11 As shown, the limiting part 420 includes a disc-shaped body 421 and petal-shaped bodies 422 evenly distributed at the bottom of the disc-shaped body 421. The disc-shaped body 421 is disc-shaped, and its diameter is basically the same as the diameter of the lower guide channel 141. The upper end of the sliding sleeve 400 has a ball seat part 411 on its inner side, on which a steel ball 500 can be placed. The ball seat part 411 is an arc surface adapted to the steel ball 500 and forms a seal for the liquid guiding channel 430. In addition, in order to ensure the stability of the sliding sleeve 400, the petal-shaped bodies 422 in this embodiment are all arc-shaped block structures, and their outer sides can fit well with the lower guide channel 141.

[0067] It should be noted that when the end section 100 is used in conjunction with the middle section 200 and the cleaning section 800 in this application, due to the obstruction of the section body 880, the sliding sleeve 400 is no longer installed inside the end section 100. The nozzle mounting hole A110 and the nozzle mounting hole B120 can be retained at the same time and the corresponding nozzle can be installed, or they can be selectively blocked as needed to enhance the corresponding single effect.

[0068] In the above embodiments, the cleaning nozzles 300 on the intermediate section 200 are all rotatably mounted in the corresponding nozzle mounting holes C210. ​​The axis of the nozzle mounting holes C210 is perpendicular to the axis of the intermediate section 200. Specifically, the cleaning nozzles 300 have a general structure as follows: Figure 15 As shown, the shape is similar to that of a conventional nozzle, but the difference is that it has at least three spiral water holes 310 inside. The spiral water holes 310 are spiral in shape, but the number of spiral turns is less than 1, and they pass through both ends of the cleaning nozzle 300. The cleaning nozzle 300 is installed in the nozzle mounting hole C210 through the bearing 600. When the water flows through the spiral water holes 310, it can drive the cleaning nozzle 300 to rotate as a whole. When it acts on the inner wall of the well, it actually forms a surface impact, which has a larger coverage area and can achieve a better impact effect compared with the traditional point impact.

[0069] In practice, the bearing 600 and the nozzle mounting hole C210, as well as the cleaning nozzle 300 and the bearing 600, can be fastened by threads or by interference fit. The nozzle mounting hole C210 can be set as a stepped hole. With the help of a special installation tool, the inner diameter of the nozzle mounting hole C210 can be larger than the outer diameter. This allows the cleaning nozzle 300 to be installed from inside the intermediate short section 200, which can improve the installation stability of the cleaning nozzle 300, facilitate replacement, and withstand greater pressure. In this case, both ends of the intermediate short section 200 are male threads, which can avoid damage to the threads during disassembly and assembly.

[0070] Of course, it is also possible to... Figures 12 to 14 The structure shown is reversed, meaning it is installed from the outside. This makes it easier to install the cleaning nozzle 300, but it is not particularly convenient for disassembly and replacement.

[0071] Based on this structure, the flow area of ​​the cleaning nozzle 300 with spiral water eye 310 gradually decreases from the inside to the outside along the radial direction of the middle short section 200, which can achieve a certain pressure boosting effect.

[0072] In addition to the structure described above, the cleaning nozzle 300 may also adopt a structure similar to a fan blade, which is supported by a shaft in the nozzle mounting hole C210. ​​The gap between adjacent blades is similar to the spiral water eye 310 structure. Similar structures are all within the protection scope of this application.

[0073] In this application, to ensure sufficient scouring coverage area while maintaining the overall strength of the intermediate section 200, the nozzle mounting holes C210 are evenly distributed in a spiral pattern along the length of the intermediate section 200. That is, all nozzle mounting holes C210 are equally spaced along both the length and circumference of the intermediate section 200.

[0074] The composite wellbore cleaning drill string assembly and cleaning method of this application can meet various well workover needs of oil and gas wells, achieve better cleaning results, improve cleaning efficiency, shorten operation time, and reduce the risk of prolonged well operation.

[0075] Finally, it should be noted that the above description is merely a preferred embodiment of the present utility model. Those skilled in the art, under the guidance of the present utility model, can make various similar representations without departing from the spirit and claims of the present utility model, and such modifications all fall within the protection scope of the present utility model.

Claims

1. A composite wellbore cleaning drill string assembly, characterized in that: It includes at least one intermediate section (200) and a cleaning section (800), and at least one cleaning section (800) is located below the lowest intermediate section (200); The intermediate short section (200) has cleaning nozzles (300) distributed circumferentially thereon. The cleaning section (800) includes a section body (880) and a rotating sleeve (830) rotatably mounted on the section body (880). The rotating sleeve (830) has a brush body structure (831) on its exterior and a hydraulically driven structure.

2. The composite wellbore cleaning drill string assembly according to claim 1, characterized in that: The short section body (880) has screw-connected parts at both the upper and lower ends. The upper part of the short section body (880) has an upper hollow section (810) with an opening facing upwards, and the lower part has a lower hollow section (820) with an opening facing downwards. The middle part of the short section body (880) is a solid body. The side wall of the upper hollow section (810) is provided with a liquid outlet (811), and the side wall of the lower hollow section (820) is provided with a liquid inlet (821). The inner wall of the rotating sleeve (830) has a gap with the short section body (880), which forms a short section annulus (840). The hydraulic drive structure includes a helical blade structure (832) disposed on the inner wall of the rotating sleeve (830).

3. The composite wellbore cleaning drill string assembly according to claim 1 or 2, characterized in that: It also includes an end section (100) located at the lower end of the drill string assembly, and the vertical distance between the lowest cleaning section (800) and the end section (100) is less than 100 meters.

4. The composite wellbore cleaning drill string assembly according to claim 3, characterized in that: The cleaning short sections (800) are arranged in pairs at intervals, or in pairs with the middle short sections (200).

5. The composite wellbore cleaning drill string assembly according to claim 2, characterized in that: The hydraulic drive structure also includes a spiral channel (833) disposed on the outer wall of the rotating sleeve (830). The upper and lower ends of the spiral channel (833) are open, and when the fluid enters the spiral channel (833) from bottom to top, the rotation direction of the rotating sleeve (830) is consistent with the rotation direction of the rotating sleeve (830) driven by the fluid impacting the spiral blade structure (832) from top to bottom.

6. The composite wellbore cleaning drill string assembly according to claim 5, characterized in that: There are at least three spiral channels (833), which are evenly distributed along the circumference of the rotating sleeve (830).

7. The composite wellbore cleaning drill string assembly according to claim 5, characterized in that: A spiral boss (834) is formed between the spiral channels (833), and the brush body structure (831) is disposed on the spiral boss (834).

8. The composite wellbore cleaning drill string assembly according to claim 1 or 2, characterized in that: The lower part of the short section body (880) has an anti-detachment step (870), the outer diameter of which is larger than the inner diameter of the rotating sleeve (830).

9. The composite wellbore cleaning drill string assembly according to claim 2, characterized in that: The spiral blade structure (832) is a continuous spiral blade or impeller structure.

10. The composite wellbore cleaning drill string assembly according to claim 1, characterized in that: The cleaning nozzle (300) is rotatably mounted on the intermediate short section (200) and has at least three spiral water holes (310).

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