Drill rod rubber plug for deep well

Abstract

The invention provides a drill rod rubber plug for a deep well, and relates to the technical field of petroleum well cementation engineering. The drill rod rubber plug for the deep well comprises a head part and a sealing structure, the sealing structure comprises a scraping part and a core shaft, the core shaft is connected to the tail end, the scraping part is elastic and surrounds the core shaft, the scraping part is of an inverted-cone-shaped structure in the first direction, and a scraping face is formed on the periphery, away from the core shaft, of the scraping part; the elastic claws are evenly arranged on the periphery of the mandrel at intervals in a surrounding mode, the elastic claws are connected with the wiping part and located at the position opposite to the wiping face of the wiping part, one end of each elastic claw is connected with the mandrel, the other end of each elastic claw extends to the end of the wiping part, and the elastic claws can retract in a reciprocating mode along with the wiping part and can support the wiping part. And the elastic modulus of the elastic claw is higher than that of the wiping part. According to the drill rod rubber plug for the deep well, elastic potential energy is released through the elastic claw, the scraping part is pushed to expand outwards, and therefore the problem that the outer diameter is reduced due to long-time abrasion of the scraping part is solved, and the problem that scraping sealing performance is insufficient due to the fact that the angle difference is too small is solved.

Description

Technical Field

[0001] This application relates to the field of oil well cementing engineering technology, and in particular to a drill pipe plug for deep wells. Background Technology

[0002] During cementing operations, traditional drill pipe plugs for deep wells face numerous challenges due to increasing drilling depth and complex geological conditions. Cementing quality is highly dependent on the effectiveness of the drill pipe plugs in isolating drilling fluid and cement slurry, and ensuring that they do not cross-contaminate. Any degree of deterioration in sealing performance will severely impact cementing results and may even lead to low production efficiency or frequent malfunctions in later stages of well development.

[0003] Especially in cementing operations in deep and ultra-deep wells, the requirements for the cleanliness of the drill pipe inner wall are even more stringent. Rubber plugs wear down over time, leading to a decline in their scraping seal performance. To meet these stringent requirements, rubber plugs not only need excellent initial sealing capabilities but also need to maintain this performance during long-term operation to cope with complex changes in the underground environment.

[0004] Therefore, how to provide a drill pipe plug for deep wells that can reduce the impact of wear on scraping and sealing performance after long-term use is an urgent problem to be solved. Summary of the Invention

[0005] To address the aforementioned technical problems, this application provides the following technical solutions: This application provides a drill pipe plug for deep wells, comprising: a head having a head end and a tail end; a sealing structure including a scraping part and a mandrel, the mandrel being connected to the tail end, the scraping part being elastic and surrounding the mandrel, the scraping part having an inverted conical structure along a first direction and forming a scraping surface on the outer periphery opposite to the mandrel; and elastic claws, a plurality of elastic claws being evenly and spaced around the mandrel, the elastic claws being in close contact with the scraping part and located opposite to the scraping surface of the scraping part, one end of the elastic claw being connected to the mandrel, and the other end extending to the end of the scraping part, the elastic claws being able to reciprocate and contract with the scraping part and providing support for the scraping part, the elastic modulus of the elastic claws being higher than the elastic modulus of the scraping part; wherein, the connection between the elastic claws and the mandrel adopts a first installation angle, and the connection between the scraping surface and the mandrel adopts a second installation angle, the first installation angle being greater than the second installation angle by 5° to 15°; the first direction being the direction from the tail end to the head end of the head.

[0006] In some modified embodiments of the first aspect of this application, there are multiple sealing structures, which are arranged sequentially along the first direction, and adjacent sealing structures are detachably connected.

[0007] In some embodiments, the second mounting angle between the scraping surfaces of the plurality of sealing structures and their corresponding mandrels decreases along a first direction.

[0008] In some embodiments, the difference between the first mounting angle and the second mounting angle of the plurality of sealing structures decreases along the first direction, with a decreasing step of 2°-3°.

[0009] In some embodiments, the first mounting angle is 10° to 15° greater than the second mounting angle.

[0010] In some embodiments, the drill pipe plug for deep wells further includes an elastic element, one end of which is connected to the mandrel and the other end of which is connected to an elastic claw. The elastic element is located at one end near the end of the mandrel and is extendable and retractable in a direction perpendicular to the first direction.

[0011] In some embodiments, the width of the elastic claw gradually increases from the mandrel connection to the end; and / or, an elastic connector is provided between the two target edges of two adjacent elastic claws.

[0012] In some embodiments, the drill pipe plug for deep wells further includes a centralizer, the central axis of which coincides with the central axis of the mandrel of the sealing structure, and the outer peripheral surface of the centralizer is provided with a multi-layered elastic bow-shaped structure, the multi-layered elastic bow-shaped structures being arranged alternately.

[0013] In some embodiments, the drill pipe plug for deep wells further includes a monitoring unit disposed on the mandrel for real-time acquisition and transmission of vibration characteristics and operating speed data of the drill pipe plug for deep wells.

[0014] In some embodiments, the drill pipe plug for deep wells further includes a wear-resistant coating, which comprises: a bottom layer covering the scraping surface of the scraping part and composed of tungsten carbide particles and a nickel-based alloy; and a top layer covering the bottom layer and composed of a graphene-polytetrafluoroethylene composite material.

[0015] In some embodiments, the end of the elastic claw connected to the mandrel forms a hook-shaped bend; and / or, the scraping surface is an arc-shaped surface that convexes away from the mandrel.

[0016] In some embodiments, the resilient claw is nested within the scraping portion.

[0017] Compared to existing technologies, the drill pipe plug for deep wells provided in the first aspect of this application employs elastic claws with an elastic modulus higher than that of the scraping part. Furthermore, the first mounting angle between the elastic claws and the mandrel is greater than the second mounting angle between the scraping surface and the mandrel by 5° to 15°, providing sufficient deformation space for the elastic claws. This allows the elastic claws to further release elastic potential energy after the scraping surface of the scraping part wears, pushing the scraping part to expand outward, thereby compensating for the reduction in outer diameter caused by wear of the scraping part. Multiple elastic claws are evenly and spaced around the mandrel, ensuring that the scraping part receives balanced support force across the entire circumference. This effectively reduces the possibility of excessive local wear, extends the service life of the drill pipe plug for deep wells, and ensures that the plug maintains close contact with the inner wall of the drill pipe even after long-term use, maintaining excellent scraping and sealing performance. Attached Figure Description

[0018] The above and other objects, features, and advantages of exemplary embodiments of this application will become readily understood by reading the following detailed description with reference to the accompanying drawings. In the drawings, several embodiments of this application are illustrated by way of example and not limitation, with the same or corresponding reference numerals denoteing the same or corresponding parts, wherein: Figure 1 A schematic diagram illustrating the working state of a drill pipe plug for deep wells is shown. Figure 2 A schematic diagram of a partial structure of a drill pipe plug for deep wells is shown. Figure 3 A schematic diagram of a partial structure of another drill pipe plug for deep wells is shown. Figure 4 A schematic diagram of a partial structure of another type of drill pipe plug for deep wells is shown. Figure 5 A schematic diagram of the structure of an elastic claw of a drill pipe plug for deep wells is shown. Figure 6 A schematic diagram of the structure of a centralizer for a drill pipe plug in a deep well is shown. Figure 7 A schematic diagram of the structure of a monitoring unit for a drill pipe plug in a deep well is shown.

[0019] Explanation of icon numbers: 1. Head; 11. Beginning end; 12. Tail end; 2. Sealing structure; 21. Scraping part; 211. Scraping surface; 22. Mandrel; 3. Elastic claw; 4. Elastic element; 5. Elastic connector; 6. Centralizer; 61. Bow-shaped structure; 7. Monitoring unit; 71. Sensor protective sleeve; 72. Wireless sensor data logger; 73. Wireless accelerometer; 8. First arc segment; 9. Second arc segment; 10. Transition surface; 13. Drill pipe; 131. Large inner diameter segment; 132. Small inner diameter segment; 133. Drill pipe inner cavity; 14. Sealing ring; A. First direction; α. First installation angle; β. Second installation angle. Detailed Implementation

[0020] Exemplary embodiments of the present disclosure will now be described in more detail with reference to the accompanying drawings. While exemplary embodiments of the present disclosure are shown in the drawings, it should be understood that the present disclosure may be implemented in various forms and should not be limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the disclosure to those skilled in the art.

[0021] It should be noted that, unless otherwise stated, the technical or scientific terms used in this application shall have the ordinary meaning as understood by one of ordinary skill in the art to which this application pertains.

[0022] The inventors discovered that in cementing operations in deep and ultra-deep wells, the cleanliness requirements of the drill pipe inner wall are extremely stringent. Under the continuous action of long-term high pressure, high temperature and complex downhole environment (such as high sand content and acidic media), the rubber plug is prone to wear and tear, which leads to a decline in the scraping and sealing performance.

[0023] like Figures 1-2 As shown, the first aspect of this application provides a drill pipe plug for deep wells, comprising: a head 1 having a front end 11 and a tail end 12; a sealing structure 2 including a scraping part 21 and a mandrel 22, the mandrel 22 being connected to the tail end 12, the scraping part 21 being elastic and surrounding the mandrel 22, the scraping part 21 having an inverted conical structure along a first direction A and forming a scraping surface 211 on the outer periphery away from the mandrel 22; and elastic claws 3, a plurality of elastic claws 3 being evenly and spaced around the mandrel 22, the elastic claws 3 being in close contact with the scraping part and located on the scraping surface of the scraping part. At opposite positions, one end of the elastic claw 3 is connected to the spindle 22, and the other end extends to the end of the scraping part. The elastic claw 3 can reciprocate and contract with the scraping part and can provide support for the scraping part. The elastic modulus of the elastic claw 3 is higher than that of the scraping part. The connection between the elastic claw 3 and the spindle 22 adopts a first mounting angle α, and the connection between the scraping surface 211 and the spindle 22 adopts a second mounting angle β. The first mounting angle α is 5° to 15° greater than the second mounting angle β. The first direction A is the direction from the tail end 12 to the head end 11 of the head 1.

[0024] In one possible case, such as Figure 1 As shown, head 1 refers to the foremost part of the drill pipe plug for deep wells, located at the very front of the entire device. It is the part that first contacts the drill pipe plug with the drilling fluid or the inside of the drill pipe 13. Head 1 can be conical, with its initial end 11 being a conical constricted end to guide the drill pipe plug as it moves within the drill pipe 13, reducing resistance encountered during its advance. The tail end 12 of head 1 can be detachably connected to the mandrel 22 via a thread, facilitating installation and maintenance. Head 1 can be replaced or adjusted according to different operational needs. Figures 1-4 As shown, the scraping part 21 can be made of fluororubber or similar highly elastic, wear-resistant materials. The scraping part 21 can be fixed to the mandrel 22 by a high-temperature vulcanization process. The scraping part 21 has an inverted conical structure along the direction from the tail end 12 to the head end 11 of the head 1 and surrounds the outer periphery of the mandrel 22. On the side away from the mandrel 22, a scraping surface 211 is formed for contacting the inner wall of the drill pipe. When the drill pipe plug for deep wells is pumped into the inner cavity 133 of the drill pipe, at least a portion of the scraping surface 211 contacts the inner wall of the drill pipe. As the drill pipe plug for deep wells moves in the inner cavity 133 of the drill pipe, the area and region of contact between the scraping surface 211 and the inner wall of the drill pipe can change. The mandrel 22 is the core skeleton of the entire device, and it can be a rod-shaped structure supported by high-strength metal materials such as stainless steel or alloy steel.

[0025] The elastic claw 3 can be made of spring steel or other high-strength elastic materials. Each elastic claw 3 can be an arc-shaped metal sheet with a flat surface, or an arc-shaped metal sheet with a wavy surface. The wavy metal sheet increases the effective length of the elastic claw 3, improving its elasticity and deformation capacity. The wavy metal sheet can provide a greater range of extension and contraction within a limited space, enhancing the support for the scraping part 21, and better dispersing stress when compressed, reducing the risk of local overload.

[0026] The side of the scraper 21 facing away from the scraping surface 211, i.e., the inner wall of the scraper 21, may have grooves or holes into which a portion of the elastic claw 3 can be embedded, forming a strong mechanical connection. The shape and curvature of the elastic claw 3 can be adapted to and completely fit the inner wall of the scraper 21. Alternatively, the elastic claw 3 can be completely embedded in the scraper 21, i.e., the elastic claw 3 is completely wrapped by the scraper 21. This arrangement can enhance the bonding strength between the two and protect the elastic claw 3 from corrosion by external media such as mud and drilling fluid. Multiple elastic claws 3 are evenly distributed around the mandrel 22. One end of each elastic claw 3 can be connected to the mandrel 22 by welding, bolting, or other means, while the other end can fit against the inner wall of the scraper 21 and extend to the end of the scraper 21, so that each part of the scraper 21 is evenly supported by the elastic claw 3. In actual operation, the drill pipe plug for deep wells may undergo multiple up-and-down movements or different diameter sections of the drill pipe 13. As the inner diameter of the drill pipe changes, the elastic claw 3 contracts and expands according to the change in contact pressure between the scraper 21 and the inner cavity of the drill pipe, to compensate for insufficient contact pressure between the scraper 21 and the inner wall of the drill pipe. The direction of contraction and expansion is from the mandrel 22 to the inner wall of the drill pipe 13 or from the inner wall of the drill pipe 13 to the mandrel 22. This ensures that appropriate support force is always provided. Furthermore, since the downhole environment is often high-temperature, a certain preset interval can be maintained between the multiple elastic claws 3, giving the elastic claws 3 a certain deformation space, which also facilitates the adaptation of the drill pipe plug for deep wells to the inner wall of the drill pipe 13 with different diameters. The elastic claw 3 is closely connected to the scraper 21, meaning there is direct physical contact between the elastic claw 3 and the scraper 21. This allows the elastic claw 3 to provide immediate support when the scraper 21 becomes thinned due to wear.

[0027] like Figure 2As shown, the first mounting angle α is the angle at the connection between the elastic claw 3 and the spindle 22, that is, the tilt angle of the elastic claw 3 relative to the spindle 22. The second mounting angle β is the angle at the connection between the scraping surface 211 and the spindle 22, that is, the tilt angle of the scraping surface 211 relative to the spindle 22. To prevent the angle difference between the first mounting angle α and the second mounting angle β from being too small, which would prevent the elastic claw 3 from providing sufficient deformation space for effective compensation and thus reduce the scraping sealing performance, and to prevent the elastic claw 3 from undergoing plastic deformation due to an excessive angle difference, the first mounting angle α and the second mounting angle β will satisfy the following relationship: the first mounting angle α is 5° to 15° greater than the second mounting angle β. The tilt angle of the elastic claw 3 relative to the spindle 22 is larger than that of the scraping surface 211. That is, in the initial state, due to the larger first mounting angle α, the elastic claw 3 is preloaded with a certain elastic potential energy and has a certain prestress state relative to the spindle 22. That is, the elastic claw 3 will form an outward expansion tendency between the spindle 22 and the scraping part 21. As usage time increases, the scraper part 21 gradually wears and thins due to friction. The elastic claw 3 releases its stored elastic potential energy by extending, applying outward pressure to push the scraper part 21 back against the inner wall of the drill pipe 13, filling the gap caused by wear. Essentially, the elastic claw 3 "unfolds" itself, returning to its original uncompressed state, thus compensating for the wear loss of the scraper part 21. Furthermore, the material selection of the elastic claw 3 gives it a higher elastic modulus than the scraper part 21, resulting in a higher support capacity. This allows it to respond and expand more quickly after the scraper part 21 wears down, providing the necessary support force to compensate for the reduction in outer diameter caused by wear.

[0028] In one possible scenario, to prevent the elastic claw 3 from becoming overly rigid due to an excessively large difference between the first mounting angle α and the second mounting angle β (e.g., exceeding 15°), resulting in limited deformation space under external force and ineffective absorption of impact and vibration, thus causing the scraper part 21 to bear greater pressure in high-pressure or large-diameter sections 131 and easily deforming or being damaged, and conversely, to prevent insufficient support due to an excessively small difference between the first mounting angle α and the second mounting angle β (e.g., less than 10°), thus increasing the risk of scraper part 21 failure due to insufficient support force, the difference between the first mounting angle α and the second mounting angle β can be controlled between 10° and 15°.

[0029] The drill pipe plug for deep wells provided in the first aspect of this application employs elastic claws 3 with an elastic modulus higher than that of the scraping part 21. The first mounting angle α between the elastic claws 3 and the mandrel 22 is greater than the second mounting angle β between the scraping surface 211 and the mandrel 22, ranging from 5° to 15°. This provides sufficient deformation space for the elastic claws 3, allowing them to further release elastic potential energy after the scraping surface 211 of the scraping part 21 wears, pushing the scraping part 21 outwards to compensate for the reduction in outer diameter caused by wear of the scraping part 21. Multiple elastic claws 3 are evenly and spaced around the mandrel 22, ensuring that the scraping part 21 receives balanced support force throughout the circumference. This effectively reduces the possibility of excessive local wear, extends the service life of the drill pipe plug for deep wells, and ensures that the plug maintains close contact with the inner wall of the drill pipe 13 even after long-term use, maintaining excellent scraping and sealing performance.

[0030] In some modified embodiments of the first aspect of this application, the number of sealing structures 2 is multiple, the multiple sealing structures 2 are arranged sequentially along the first direction A, and adjacent sealing structures 2 are detachably connected.

[0031] In one possible case, such as Figure 1 As shown, the number of sealing structures 2 can be set according to actual needs, such as 2, 3, or 5. Each sealing structure 2 includes a scraping part 21, a mandrel 22, and an elastic claw 3 adapted to the scraping part 21. Multiple sealing structures 2 are arranged sequentially along the first direction A, forming multiple scraping surfaces 211 arranged sequentially along the first direction A. One end of each mandrel 22 is an external thread (male thread), and the other end is an internal thread (female thread), so that two adjacent sealing structures 2 can be detachably connected through the thread structure of the mandrel 22. When two mandrel sections 22 are connected, the external thread at one end can be screwed into the internal thread at the other end to form a firm connection. When the scraping surface 211 of a certain sealing structure 2 suffers severe wear or other problems, only that part needs to be replaced, instead of replacing the entire structure, reducing maintenance costs and extending the service life of the entire deep well drill pipe plug. Multiple sealing structures 2 provide multi-layer sealing protection. Even if the scraping surface 211 of one layer is worn and cannot effectively adhere to the inner wall of the drill pipe 13, cannot effectively remove the mud inside the drill pipe 13, or cannot achieve effective isolation, the scraping surfaces 211 of other layers can remain in close contact, further removing the mud inside the drill pipe.

[0032] In some embodiments, the second mounting angle β between the scraping surface 211 of the plurality of sealing structures 2 and their corresponding mandrel 22 decreases along the first direction A.

[0033] In one possible case, such as Figure 1As shown, each sealing structure 2 has its own independent scraping part 21 and mandrel 22. The second mounting angle β between the scraping surface 211 and the mandrel 22 decreases along the first direction A. That is, the closer the sealing structure 2 is to the head 1, the smaller its second mounting angle β is, that is, the smaller the diameter of the inverted conical scraping part 21 away from the bottom of the head 1. Conversely, the closer the sealing structure 2 is to the tail end 12, the larger its second mounting angle β is, that is, the larger the diameter of the inverted conical scraping part 21 away from the bottom of the head 1. This is suitable for drill pipes 13 with decreasing inner diameters. Alternatively, the closer the sealing structure 2 is to the head 1, the larger its second mounting angle β is, that is, the larger the diameter of the inverted conical scraping part 21 away from the bottom of the head 1. Conversely, the closer the sealing structure 2 is to the tail end 12, the smaller its second mounting angle β is, that is, the smaller the diameter of the inverted conical scraping part 21 away from the bottom of the head 1. This is suitable for drill pipes 13 with increasing inner diameters. The decreasing step size can be set according to the change in the inner diameter of the drill pipe 13.

[0034] This explanation uses the example of a deep well drill pipe plug entering a drill pipe 13 with a decreasing inner diameter, where the second installation angle β between the scraping surface 211 and the mandrel 22 decreases along the first direction A. When the deep well drill pipe plug first enters the large inner diameter section 131 of the drill pipe 13, the portion of the scraping surface 211 of the sealing structure 2 near the tail end 12 that faces away from the head 1 first contacts the inner wall of the drill pipe cavity 133. The elastic claw 3 mainly serves a supporting function, ensuring that the scraping part 21 can evenly conform to the inner wall of the drill pipe 13, so as to remove mud and other impurities inside the drill pipe 13 as the deep well drill pipe plug moves. Since the inner diameter is large at this time, the elastic claw 3 does not need to apply too much pressure; this is mainly to prevent the scraping part 21 from losing its scraping and sealing performance due to slight deformation and from failing to remove impurities inside the drill pipe 13. At this time, the scraping surface 211 of the sealing structure 2 near the head 1 can contact the inner wall of the drill rod 13, but the contact pressure is less than the contact pressure between the scraping surface 211 of the sealing structure 2 near the tail and the inner wall of the drill rod 13. Alternatively, the scraping surface 211 of the sealing structure 2 near the head 1 may not contact the inner wall of the drill rod 13. At this time, the main purpose of the sealing structure 2 near the head 1 is to prepare for subsequent entry into the smaller inner diameter section 132. Subsequently, as the drill pipe plug moves downwards along the inner cavity 133 of the drill pipe, the scraping surface 211 of the sealing structure 2 near the tail end remains in contact with the cavity wall of the smaller inner diameter section within the drill pipe 13, further cleaning the cavity of that section. Due to the reduced inner diameter, the contact area between the scraping surface 211 and the drill pipe cavity, as well as the pressure exerted by the drill pipe cavity wall on the scraping surface 211, increases. Meanwhile, the scraping surface 211 of the sealing structure 2 near the head 1 also contacts the cavity wall of the smaller inner diameter section, further cleaning that section. By setting a decreasing second installation angle β, the drill pipe plug can flexibly adapt to composite drill pipes with different inner diameters. Whether in the larger inner diameter section 131 or the smaller inner diameter section 132, the scraping part 21 can effectively remove mud and other impurities from the drill pipe 13. Especially when entering the smaller inner diameter section 132, due to the increased contact area, the scraping part 21 can more thoroughly clean the impurities in the cavity. In addition, multiple sealing structures 2 help to distribute pressure and wear, reduce the burden on individual components, and further extend the service life of each sealing structure 2.

[0035] In some embodiments, the difference between the first mounting angle α and the second mounting angle β of the plurality of sealing structures 2 decreases along the first direction A, with a decreasing step of 2°-3°.

[0036] In one possible scenario, where the drill pipe plug for deep wells includes multiple sealing structures 2, during the operation of the drill pipe plug within the drill pipe cavity 133, the scraping surface 211 of the sealing structure 2 near the tail end is constantly in contact with and rubs against the wall of the drill pipe cavity 133 for an extended period. The scraping surface 211 near the tail end experiences more wear than the scraping surface 211 near the head end. To compensate for this wear difference and ensure consistently effective scraping and sealing performance throughout the process, this embodiment employs a setting where the difference between the first installation angle α and the second installation angle β of the multiple sealing structures 2 decreases along a first direction A, with a decreasing step size of 2°-3°. For example, the difference between the first installation angle α and the second installation angle β of the first sealing structure 2 is 15°, the second is 13°, the third is 11°, and so on. The sealing structure 2 near the tail end has a large difference (e.g., 15°) between its first mounting angle α and second mounting angle β, meaning the elastic claw 3 has more deformation space to compensate for wear of the scraper 21 or adapt to changes in the larger inner diameter section 131. This larger angle difference allows the elastic claw 3 to expand more effectively and apply outward pressure after wear of the scraper 21, maintaining good contact with the inner wall of the drill pipe 13. The sealing structure 2 near the head 1, due to its forward position, only begins to contact the inner wall of the drill pipe cavity 133 when entering the smaller inner diameter section 132, thus experiencing relatively less wear. The smaller difference between the first mounting angle α and the second mounting angle β of the sealing structure 2 allows the elastic claw 3 to provide stronger support, ensuring that the scraper 21 also fits tightly against the inner wall of the drill pipe 13 within the smaller inner diameter section 132, providing a reliable seal.

[0037] In some embodiments, the drill pipe plug for deep wells further includes: an elastic member 4, one end of which is connected to the mandrel 22 and the other end is connected to an elastic claw 3 on the inner wall of the scraping part 21. The elastic member 4 is located at one end near the end of the mandrel 22 and can extend and retract in a direction perpendicular to the first direction A.

[0038] In one possible case, such as Figures 2-3As shown, an elastic element 4 can be installed in the drill pipe plug for deep wells. The elastic element 4 is a mechanical component or material that can deform under force and return to its original shape after the external force is removed; here, it can be a spring. One end of the elastic element 4 can be welded to the mandrel 22, and the other end can be welded to the elastic claw 3 on the inner wall of the scraping part 21. Each elastic claw 3 can correspond to one elastic element 4 or multiple elastic elements 4. When the drill pipe plug for deep wells falls from the larger inner diameter section 131 to the smaller inner diameter section 132, the elastic claw 3 will suddenly be subjected to a large contact pressure. At this time, the elastic element 4 can quickly contract and provide additional support for the elastic claw 3, preventing it from plastically deforming due to sudden pressure and getting too close to the mandrel 22. In order to enable the elastic element 4 to support the elastic claw 3 in a timely manner, the elastic element 4 can be positioned near the end of the mandrel 22.

[0039] In some embodiments, the width of the elastic claw 3 gradually increases from the connection point of the mandrel 22 to the end; and / or, an elastic connector 5 is provided between the two target edges of two adjacent elastic claws 3.

[0040] In one possible case, such as Figure 5 As shown, the width of the elastic claw 3 gradually increases from the connection point to the end. That is, the elastic claw 3 is wider near the scraper part 21 and narrower near the connection point of the mandrel 22. Through this gradual transition, the elastic claw 3 can provide appropriate support and flexibility at different positions. The wider portion provides stronger support, while the narrower portion maintains better flexibility, allowing the narrower portion to better adapt to changes in the inner diameter of the drill pipe 13 and slight irregularities in the surface, reducing unnecessary deformation and frictional resistance. The wider portion provides stronger support, ensuring that the scraper part 21 can better conform to the inner wall of the drill pipe 13. In addition, the wider end of the elastic claw 3 can distribute the pressure applied to the scraper part 21 over a larger area, preventing premature failure due to excessive force in local areas. This allows the scraper part 21 to receive balanced support force throughout its circumference, extending the service life of the drill pipe plug for deep wells.

[0041] The elastic connector 5 can be a spring or a highly elastic rope, etc. The target edges of two adjacent elastic claws 3 can be connected by the elastic connector 5. The elastic connector 5 can be positioned near the end of the elastic member 4, close to the end of the scraping part 21. Figure 5 As shown, it can also be set at the middle section of the extension of the elastic connector 5, and one or more elastic connectors 5 can be set at the target edge of two adjacent elastic claws 3. The elastic connector 5 can establish a cooperative effect between multiple elastic claws 3, so that each elastic claw 3 can support each other when subjected to external pressure, thereby enhancing the stability and reliability of the overall structure.

[0042] In some embodiments, the drill pipe plug for deep wells further includes a centralizer 6, the central axis of which coincides with the central axis of the mandrel 22 of the sealing structure 2, and the outer peripheral surface of the centralizer 6 is provided with a multi-layered elastic bow-shaped structure 61, and the multi-layered elastic bow-shaped structures 61 are staggered.

[0043] In one possible case, such as Figure 1 As shown, the centralizer 6 is used to improve the centering and stability of the drill pipe plug in the wellbore. The central axis of the centralizer 6 coincides with the central axis of the mandrel 22 of the sealing structure 2. The outer dimensions of the centralizer 6 can be set according to the dimensions of the drill pipe 13. Figure 6 As shown, the outer peripheral surface of the centralizer 6 is provided with a multi-layered elastic bow-shaped structure 61. The elastic bow-shaped structure 61 can be made of highly elastic metals (such as spring steel or stainless steel) or highly elastic polymers (such as polyurethane or rubber-like materials). The multi-layered elastic bow-shaped structure 61 can be divided into two or three layers, etc., with each layer containing several independent bow-shaped structures 61. The elastic bow-shaped structure 61 can extend outward from the main body of the centralizer 6 and undergo elastic deformation when in contact with the well wall. To ensure that the centralizer 6 can provide uniform support force in all directions, each layer of elastic bow-shaped structure 61 should be evenly distributed on the outer peripheral surface of the centralizer 6. For example, if a layer has four bow-shaped structures 61 on a circumference, they can be evenly distributed on a 360-degree circumference, that is, the angle between each bow-shaped structure 61 is 90 degrees. The elastic bow-shaped structure 61 can adopt a variable cross-section setting, that is, its thickness gradually decreases from the root to the tip. This can increase the flexibility at the end while maintaining sufficient strength and rigidity, making it better adaptable to the changes in the inner diameter of the composite drill pipe 13. The staggered arrangement refers to the fact that the elastic bow-shaped structures 61 in different layers are not completely aligned, but arranged in a staggered manner. For example, the bow-shaped structures 61 in the first layer are located at 0 degrees, 90 degrees, 180 degrees, and 270 degrees, while the bow-shaped structures 61 in the second layer are located at 45 degrees, 135 degrees, 225 degrees, and 315 degrees. This arrangement allows the bow-shaped structures 61 in each layer to be spatially staggered, thereby providing more uniform support in all directions and improving the stability of the centralizer 6.

[0044] In some embodiments, the drill pipe plug for deep wells further includes a monitoring unit 7, which is disposed on the mandrel 22 and is used to collect and transmit vibration characteristics and operating speed data of the drill pipe plug for deep wells in real time.

[0045] In one possible case, such as Figure 1 , Figure 7As shown, the monitoring unit 7 may include: a sensor protective sleeve 71, a wireless sensor data logger 72, and a wireless accelerometer 73. The wireless sensor data logger 72 and the wireless accelerometer 73 are combined and fixed together within the sensor protective sleeve 71. The sensor protective sleeve 71 is threadedly fixed to the spindle 22 of the drill pipe plug for deep wells. The sensor protective sleeve 71 provides good protection for the wireless sensor data logger 72 and the wireless accelerometer 73, protecting them from the harsh downhole environment, including high temperature, high pressure, and chemical corrosion. The wireless accelerometer 73 is used to detect the vibration characteristics of the drill pipe plug for deep wells, including parameters such as vibration frequency and amplitude. Furthermore, it can infer the operating speed of the plug by analyzing vibration patterns. The wireless sensor data logger 72 receives data from the wireless accelerometer 73, performs preliminary processing, and then transmits the data to a ground station via wireless communication technology. It may include a microprocessor, memory, and a wireless communication module. Surface workers can receive and analyze data transmitted from the drill pipe plugs in deep wells using specialized software or equipment, and monitor the plugs' motion characteristics, such as vibration characteristics and operating speed, in real time. By integrating the monitoring unit 7 into the drill pipe plugs in deep wells, not only can the vibration characteristics and operating speed of the plugs be monitored in real time, but important decision support information can also be provided to surface workers, improving the safety, efficiency, and reliability of drilling operations.

[0046] In some embodiments, the drill pipe plug for deep wells further includes: a wear-resistant coating comprising: a bottom layer covering the scraping surface 211 of the scraping portion 21 and composed of tungsten carbide particles and a nickel-based alloy; and a top layer covering the bottom layer and composed of a graphene-polytetrafluoroethylene composite material.

[0047] In one possible scenario, embedding tungsten carbide particles into a nickel-based alloy can form a hard and durable base layer. Covering the wiping surface 211 with this base layer effectively resists wear during wiping, with a thickness ranging from 100 to 500 micrometers. The surface layer is composed of a graphene-polytetrafluoroethylene (PTFE) composite material, with a thickness ranging from 20 to 100 micrometers. This provides effective low-friction and self-lubricating properties without adding unnecessary costs or affecting the overall performance of the coating due to excessive thickness. Graphene, a two-dimensional nanomaterial, possesses extremely high strength and excellent electrical and thermal conductivity. Combining it with PTFE not only further enhances the mechanical strength of the coating but also improves its durability and stability. The graphene-PTFE composite material exhibits self-lubricating properties, maintaining a low coefficient of friction even during prolonged use, reducing the need for additional lubricants. By applying a base layer composed of tungsten carbide particles and a nickel-based alloy, and a surface layer composed of graphene-PTFE composite material, to the scraping section 21 of the drill pipe plug for deep wells, its wear resistance, corrosion resistance, and lubrication performance can be improved. This dual-layer coating design not only improves the overall performance of the drill pipe plug for deep wells but also significantly extends its service life and reduces maintenance costs. In some embodiments, the end of the elastic claw 3 connected to the spindle 22 forms a hook-shaped bend; and / or, the scraping surface 211 is an arc-shaped surface that protrudes in the direction away from the spindle 22.

[0048] In one possible case, such as Figure 1 As shown, the end of the elastic claw 3 connected to the spindle 22 is designed as a hook-shaped bend, similar to the letter "J," forming a semi-closed annular structure, or hook-shaped bend, at one end of the elastic claw 3. The hook-shaped bend allows the elastic claw 3 more elastic deformation space after being subjected to force, thereby improving its elastic recovery capability. When the elastic claw 3 is subjected to greater pressure, the hook-shaped part can bend moderately and absorb some energy, avoiding stress concentration directly applied to the connection point and extending its service life.

[0049] The arc-shaped scraping surface 211 ensures more uniform contact between the scraping part 21 and the inner wall of the wellbore, forming a tighter seal and facilitating the removal of mud or other impurities from the wellbore's inner wall. As the scraping part 21 moves along the drill pipe's inner cavity 133, the arc-shaped surface effectively pushes these impurities to both sides, preventing their accumulation on the surface of the scraping part 21, thus maintaining its cleanliness and effectiveness. Figure 3As shown, the arc surface can be a multi-arc arc surface, divided into a first arc segment 8 and a second arc segment 9. When the drill pipe rubber plug moves through different inner diameter segments of the drill pipe 13 in the deep well, the multi-arc arc surface can flexibly adjust its shape to adapt to the new diameter size, ensuring that it always maintains close contact with the pipe wall. It can also use the transition surface 10 between its first arc segment 8 and second arc segment 9 to push the mud in the drill pipe 13 downward, which is conducive to cleaning.

[0050] Furthermore, in order to facilitate the movement of the deep well drill pipe plug from the larger inner diameter section to the smaller inner diameter section within the cavity of the composite drill pipe 13, the thickness of the scraping portion 21 of the multiple sealing structures 2 can be reduced along the first direction A. This allows the scraping portion 21 of the sealing structure 2 facing away from the head 1 to be thinner, providing better flexibility and adaptability, and facilitating deformation from the larger inner diameter section 131 to the smaller inner diameter section 132. An annular groove may be provided on the outer periphery of the head 1 for embedding the sealing ring 14, thereby improving the scraping seal performance of the deep well drill pipe plug when connected with other plugs.

[0051] It should be noted that in the description of this specification, the terms "upper," "lower," etc., indicating the orientation or positional relationship are based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of the present invention; the terms "connection," "installation," "fixing," etc., should be interpreted broadly. For example, "connection" can be a fixed connection, a detachable connection, or an integral connection; it can be a direct connection or an indirect connection through an intermediate medium. For those skilled in the art, the specific meaning of the above terms in the present invention can be understood according to the specific circumstances.

[0052] In the description of this specification, the terms "one embodiment," "some embodiments," "specific embodiment," etc., refer to a specific feature, structure, material, or characteristic described in connection with that embodiment or example, which is included in at least one embodiment or example of the present invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0053] The above description is merely a specific embodiment of this application, but the scope of protection of this application is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in this application should be included within the scope of protection of this application. Therefore, the scope of protection of this application should be determined by the scope of the claims.

Claims

1. A drill pipe plug for deep wells, characterized in that, include: The head, which has a proximal end and a tail end; The sealing structure includes: The scraping part and the mandrel are connected to the tail end. The scraping part is elastic and surrounds the mandrel. The scraping part has an inverted conical structure along a first direction and forms a scraping surface on the outer periphery away from the mandrel. Elastic claws, a plurality of elastic claws are evenly and spaced around the mandrel. The elastic claws are connected to the scraping part in close contact and are located opposite to the scraping surface of the scraping part. One end of the elastic claw is connected to the mandrel and the other end extends to the end of the scraping part. The elastic claws can reciprocate and retract with the scraping part and can provide support for the scraping part. The elastic modulus of the elastic claws is higher than that of the scraping part. The elastic claw is connected to the spindle at a first mounting angle, and the scraping surface is connected to the spindle at a second mounting angle. The first mounting angle is 5° to 15° greater than the second mounting angle. The first direction is the direction from the tail end to the head end of the head.

2. The drill pipe plug for deep wells according to claim 1, characterized in that, The number of sealing structures is multiple, and the multiple sealing structures are arranged sequentially along the first direction, and adjacent sealing structures are detachably connected.

3. The drill pipe plug for deep wells according to claim 2, characterized in that, The second mounting angle between the scraping surfaces of the plurality of sealing structures and their corresponding mandrels decreases along the first direction.

4. The drill pipe plug for deep wells according to claim 3, characterized in that, The difference between the first mounting angle and the second mounting angle of the plurality of sealing structures decreases along the first direction, with a decreasing step of 2°-3°.

5. The drill pipe plug for deep wells according to claim 1, characterized in that, The first mounting angle is 10° to 15° greater than the second mounting angle.

6. The drill pipe plug for deep wells according to claim 2, characterized in that, Also includes: An elastic element, one end of which is connected to the mandrel and the other end of which is connected to the elastic claw, is located at the end near the end of the mandrel, and the elastic element can extend and retract in a direction perpendicular to the first direction.

7. The drill pipe plug for deep wells according to claim 1, characterized in that, The width of the elastic claw gradually increases from the mandrel connection to the end; and / or, An elastic connector is provided between the two target edges of two adjacent elastic claws.

8. The drill pipe plug for deep wells according to claim 1, characterized in that, Also includes: The central axis of the centralizer coincides with the central axis of the mandrel of the sealing structure, and the outer peripheral surface of the centralizer is provided with a multi-layered elastic bow-shaped structure, and the multi-layered elastic bow-shaped structures are arranged alternately.

9. The drill pipe plug for deep wells according to claim 1, characterized in that, Also includes: A monitoring unit, mounted on the mandrel, is used to collect and transmit in real time the vibration characteristics and operating speed data of the drill pipe plug for deep wells.

10. The drill pipe plug for deep wells according to claim 1, characterized in that, Also includes: Abrasion-resistant coatings, including: The bottom layer covers the wiping surface of the wiping part and is composed of tungsten carbide particles and a nickel-based alloy. The surface layer covers the bottom layer and is composed of a graphene-polytetrafluoroethylene composite material.

11. The drill pipe plug for deep wells according to claim 1, characterized in that, The end of the elastic claw connected to the mandrel forms a hook-shaped bend; and / or The scraping surface is an arc-shaped surface that bulges away from the spindle.

12. The drill pipe plug for deep wells according to claim 1, characterized in that, The elastic claw is nested within the scraping part.

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