Coring drill bit and coring drilling equipment
By designing a core drill bit with cutting teeth and elastic claws, combined with a centering component and a water-hole structure, the problem of low core recovery rate in fractured formations was solved, achieving stable core clamping and efficient core extraction.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- CHINA NAT PETROLEUM CORP
- Filing Date
- 2024-10-15
- Publication Date
- 2026-04-17
Smart Images
Figure CN121875612A_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of drill bit design technology, and in particular to a core drilling bit and core drilling equipment. Background Technology
[0002] In the field of oil and gas exploration, coring is a common method for obtaining formation samples, which is accomplished by coring drilling equipment. During coring drilling, it is necessary to ensure that the coring drilling equipment can guarantee a certain coring yield. A low coring yield means that less material is obtained from the core, which is detrimental to determining reserves and analyzing reservoir genesis.
[0003] Coring in fractured formations has long been a challenging and difficult area to overcome. Industry standards for coring in fractured formations generally require a core recovery rate of around 50%. However, in actual coring drilling, this is often difficult to achieve, severely hindering the efficient progress of exploration work.
[0004] Improving the core recovery rate of core drilling equipment is an urgent problem to be solved by technical personnel in related fields. Summary of the Invention
[0005] This invention discloses a coring drill bit and coring drilling equipment to solve the problem of low coring recovery rate in related technologies.
[0006] To address the aforementioned technical problems, the present invention discloses the following technical solutions:
[0007] On one hand, an embodiment of the present invention discloses a core drill bit, including a cylindrical drill bit body and a core claw; the cylindrical drill bit body includes a drilling end, the annular end face of the drilling end is provided with cutting teeth distributed along its circumference, the cylindrical cavity of the cylindrical drill bit body includes a conical space, the core claw includes an annular base and a plurality of elastic claw bodies spaced apart along the circumference of the annular base, the annular base is attached to the inner wall of the conical space, the first end of the plurality of elastic claw bodies is connected to the annular base, the second end of the plurality of elastic claw bodies forms a clamping space, the clamping space is connected to the core inlet of the drilling end, and the second end of the plurality of elastic claw bodies is used to clamp the core entering the clamping space through the core inlet.
[0008] In one embodiment, the clamping space includes a constant-diameter space and a tapering space. The tapering space is connected to the constant-diameter space and is located between the core inlet and the constant-diameter space. The larger port of the tapering space faces the core inlet, and the smaller port of the tapering space is connected to the constant-diameter space. The central axis of the constant-diameter space coincides with the central axis of the conical space and the central axis of the cylindrical cavity.
[0009] In one embodiment, the annular base and the plurality of elastic claws are an integral structure.
[0010] In one embodiment, the annular base and the plurality of elastic claws form a conical structure, wherein the surface of the conical structure facing the inner wall of the conical space is adapted to and in contact with the shape of the inner wall of the conical space.
[0011] In one embodiment, the core drill bit further includes a centering assembly, which includes a connecting sleeve and a plurality of rolling elements. The connecting sleeve is fixed inside the cylinder cavity and located above the core claw. The plurality of rolling elements are distributed along the circumferential direction of the connecting sleeve, and are embedded in the inner wall of the connecting sleeve, with part of the rolling surface exposed and protruding from the inner wall of the connecting sleeve.
[0012] In one embodiment, the connecting sleeve is fixedly connected to the cylindrical drill bit body by means of a threaded connection.
[0013] In one embodiment, the straightening assembly further includes multiple sealing rings disposed between the connecting sleeve and the cylindrical drill bit body, and tensioning the connecting sleeve.
[0014] In one embodiment, the cylindrical drill bit body has a plurality of water holes, which are spaced apart along the circumference of the cylindrical drill bit body. The inner ports of the plurality of water holes are located on the inner wall of the cylindrical drill bit body and below the core claw, while the outer ports of the plurality of water holes are located on the outer wall of the cylindrical drill bit body. The annular base and the elastic claw body have through grooves, which together with the inner wall of the cylindrical cavity form a water passage, which communicates with the inner ports of the water holes.
[0015] In one embodiment, the water eye includes a first water passage section and a second water passage section extending at an angle. The first port of the first water passage section is the inner port of the water eye. The second port of the first water passage section is connected to the first port of the second water passage section. The second port of the second water passage section is the outer port of the water eye. The junction of the first water passage section and the second water passage section is lower than the first port of the first water passage section and also lower than the second port of the second water passage section.
[0016] On the other hand, embodiments of the present invention disclose a coring drilling device, which includes the coring drill bit described above.
[0017] The technical solutions disclosed in the embodiments of the present invention have the following technical effects:
[0018] During the drilling process of a core drilling rig, the drill bit continuously rotates, cutting the rock strata to form a columnar core. This columnar core enters the cylindrical cavity of the drill bit body through the core inlet. Inside the cavity, the core is held in a clamping space by multiple elastic claws, providing a lateral clamping force. This lateral clamping force is perpendicular to the penetration direction of the core inlet, helping to maintain the core's columnar shape and prevent it from dispersing. Because the core is less likely to disperse during core drilling in fractured strata, it is less likely to fall through the core inlet, ensuring a sufficient amount of core enters the strata and ultimately improving the core recovery rate. Attached Figure Description
[0019] Figure 1 This is a schematic diagram of the core drill bit disclosed in an embodiment of the present invention;
[0020] Figure 2 yes Figure 1 A bottom view.
[0021] The components in the diagram are labeled as follows:
[0022] 10-Cylindrical drill bit body, 11-Drilling end, 12-Connecting end, 13-Cylinder cavity, 14-Core inlet, 15-Water hole, 151-First water passage section, 152-Second water passage section
[0023] 20-Core claw, 21-Annular base, 22-Elastic claw body, 23-Clamping space, 231-Equal diameter space, 232-Gradually narrowing space
[0024] 30-Cutting teeth, 31-Composite plates, 32-Size-maintaining teeth,
[0025] 40-Straightening component, 41-Connecting sleeve, 42-Rolling element, 43-Sealing ring. Detailed Implementation
[0026] To make the objectives, technical solutions, and advantages of this invention clearer, the technical solutions of this invention will be clearly and completely described below in conjunction with specific embodiments and corresponding drawings. Obviously, the described embodiments are only a part of the embodiments of this invention, and not all of them. Based on the embodiments of this invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this invention.
[0027] The technical solutions disclosed in the various embodiments of the present invention will be described in detail below with reference to the accompanying drawings.
[0028] Please refer to Figures 1 to 2This invention discloses a core drilling bit, which belongs to core drilling equipment. The core drilling bit disclosed in this invention includes a cylindrical drill bit body 10 and a core claw 20.
[0029] The cylindrical drill bit body 10 is the main structure of the core drill bit, and it is a hollow cylindrical structure. The cylindrical drill bit body 10 includes a drilling end 11 and a connecting end 12. The drilling end 11 is the end where the core drill bit drills, used for breaking rock formations. The connecting end 12 is the end where the cylindrical drill bit body 10 connects to the drill rod of the core drilling equipment. The connecting end 12 and the drilling end 11 are the two opposite ends of the cylindrical drill bit body 10. The connecting end 12 can be connected to the drill rod of the core drilling equipment through connectors, threaded connections, or other methods. This embodiment of the invention does not limit the specific connection method of the connecting end 12.
[0030] The drilling end 11 has an annular end face, which forms a core inlet 14. The annular end face of the drilling end 11 is provided with cutting teeth 30 distributed along its circumference. During the drilling process of the core drill bit, the cutting teeth 30 will break the rock, thereby forming a columnar core. The columnar core will enter the cylinder cavity 13 of the cylindrical drill bit body 10 from the core inlet 14. As drilling continues, the continuously formed core will be continuously fed into the cylinder cavity 13 and form a longer core.
[0031] In one embodiment, such as Figure 2 As shown, the cutting teeth 30 may include multiple composite plates 31 and multiple diameter-maintaining teeth 32. The multiple composite plates 31 are arranged in a circle, and the multiple diameter-maintaining teeth 32 are arranged in a circle, with the multiple composite plates 31 and multiple diameter-maintaining teeth 32 being distributed alternately. The space enclosed by the multiple diameter-maintaining teeth 32 can determine the diameter of the formed rock core. The composite plates 31 are made of a material with high hardness, which is beneficial for achieving efficient cutting of fractured strata.
[0032] The cylindrical drill bit body 10 has a conical cavity 13. The core claw 20 includes an annular base 21 and multiple elastic claw bodies 22, which are spaced apart along the circumference of the annular base 21. The annular base 21 is attached to the inner wall of the conical cavity. Specifically, the annular base 21 serves as the foundation of the core claw 20, mainly cooperating with the cylindrical drill bit body 10 to prevent the core claw 20 from moving away from the core inlet 14. This ensures the position of the multiple elastic claw bodies 22 is determined, thus ensuring the approximate position of the clamping space 23 formed by the multiple elastic claw bodies 22. Consequently, the multiple elastic claw bodies 22 clamp the core at their predetermined positions within the cavity.
[0033] Specifically, the first ends of multiple elastic claws 22 are connected to the annular base 21, and the second ends of the multiple elastic claws 22 form a clamping space 23, which is connected to the core inlet 14 of the drilling end 11. The second ends of the multiple elastic claws 22 are used to clamp the core that enters the clamping space 23 through the core inlet 14.
[0034] During the drilling process of the core drilling equipment, the drilling end 11 of the core drill bit continuously rotates and drills forward. Simultaneously, the cutting teeth 30 cut through the rock strata to form a columnar core. This columnar core enters the cylinder 13 of the main body 10 of the cylindrical drill bit through the core inlet 14. The core inside the cylinder 13 enters the clamping space 23 and is clamped by multiple elastic claws 22, thus applying a lateral clamping force to the core extracted from the fractured strata. This lateral clamping force is perpendicular to the penetration direction of the core inlet 14, which helps to maintain the core's columnar shape and prevents it from dispersing. During core drilling in fractured strata, because the core is less likely to disperse, it is also less likely to fall through the core inlet 14 and disperse. This ensures the amount of core entering through the core inlet 14, ultimately improving the core recovery rate of the core drill bit.
[0035] When the core tends to detach, friction occurs between the core and multiple elastic claws 22. The falling core causes the elastic claws 22 to fall as well, resulting in the core claws 20 moving downwards along the inner wall of the conical space. As the space narrows, the core claws 20 further press against the core, thus securing it and preventing detachment. In other words, the core claws 20 adhere to the inner wall of the conical space and can slide along it within a small range.
[0036] The shape of the clamping space 23 is not limited in this embodiment of the invention, nor is the specific shape of the elastic claw 22. In one embodiment, the clamping space 23 may include a constant-diameter space 231 and a tapering space 232. The tapering space 232 is connected to the constant-diameter space 231 and is located between the core inlet 14 and the constant-diameter space 231. The larger port of the tapering space 232 faces the core inlet 14, and the smaller port of the tapering space 232 is connected to the constant-diameter space 231. The central axis of the constant-diameter space 231 coincides with the central axis of the conical space and the central axis of the cylindrical cavity 13. The tapering space 232 allows the core to easily enter the clamping space 23 from the larger port, and then be clamped by the elastic claw 22 in the constant-diameter space 231.
[0037] The annular base 21 and the multiple elastic claws 22 can be connected by welding, bonding, or connecting with connectors. In other embodiments, the annular base 21 and the multiple elastic claws 22 can be an integral structure.
[0038] As described above, the cavity 13 includes a conical space; specifically, a portion of the inner wall of the cylindrical drill bit body 10 forms a conical space. To facilitate installation within the cylindrical drill bit body 10, in a further embodiment, the annular base 21 and a plurality of elastic claws 22 form a conical structure. The surface of the conical structure facing the inner wall of the conical space is adapted to and contacts the shape of the inner wall of the conical space, thereby enabling better installation of the core claw 20.
[0039] The core drill bit disclosed in this embodiment of the invention may further include a centering assembly 40, which may include a connecting sleeve 41 and a plurality of rolling elements 42. The connecting sleeve 41 is the basic component of the centering assembly 40, which can realize the connection between the centering assembly 40 and the cylindrical drill bit body 10, and also provide a mounting base for the plurality of rolling elements 42.
[0040] The connecting sleeve 41 is fixed in the cylindrical cavity 13 and is located above the core claw 20. The plurality of rolling elements 42 can be distributed along the circumference of the connecting sleeve 41. The plurality of rolling elements 42 can be embedded in the inner wall of the connecting sleeve 41, with the rolling surfaces of the rolling elements 42 exposed and protruding from the inner wall of the connecting sleeve 41. The diameter of the circumference of the surfaces of the rolling elements 42 protruding from the inner wall of the connecting sleeve 41 can be equal to the diameter of the equal-diameter space 231, thus enabling rolling contact with the core moving upwards from the equal-diameter space 231. Since the rolling elements 42 can only roll and do not move, they can maintain the upward movement of the core through rolling contact, thereby preventing core tilting and damage, which also helps to improve the core harvest rate.
[0041] In this embodiment of the invention, the rolling element 42 can be a ball or a roller, and the specific shape of the rolling element 42 is not limited in this embodiment of the invention.
[0042] In this embodiment of the invention, the connecting sleeve 41 can be fixedly connected to the cylindrical drill bit body 10 by welding, connecting with connectors, or other methods. In one embodiment, the connecting sleeve 41 can be fixedly connected to the cylindrical drill bit body 10 by threaded engagement.
[0043] In a further embodiment, the core drill bit disclosed in this invention may further include multiple sealing rings 43, which are disposed between the connecting sleeve 41 and the cylindrical drill bit body 10 and tension the connecting sleeve 41. In this structure, the multiple sealing rings 43 not only prevent drilling fluid (e.g., water) from entering the threaded fit gap between the connecting sleeve 41 and the cylindrical drill bit body 10 and causing adverse effects (e.g., excessive erosion of the mating parts between the connecting sleeve 41 and the cylindrical drill bit body 10), but also, the tensioning effect of the multiple sealing rings 43 can prevent the threaded fit between the connecting sleeve 41 and the cylindrical drill bit body 10 from loosening, thereby preventing the centering assembly 40 from falling off and ensuring the stability of the centering assembly 40 installation.
[0044] In other embodiments, there may be one sealing ring 43. Multiple sealing rings 43 provide better performance than a single sealing ring 43. It should be noted that the embodiments of the present invention do not limit the number of sealing rings 43 included in the straightening assembly 40.
[0045] In the core drilling bit disclosed in this embodiment of the invention, the cylindrical drill bit body 10 may have multiple water holes 15. These water holes 15 allow drilling fluid to pass through and generate jets, and the circulation of the drilling fluid transports the broken rock cuttings formed at the bottom of the well to the surface. The multiple water holes 15 may be spaced apart along the circumference of the cylindrical drill bit body 10. The inner ports of the multiple water holes 15 may be located on the inner wall of the cylindrical drill bit body 10 and below the core claw 20.
[0046] The outer ports of the plurality of water holes 15 can be opened on the outer wall of the cylindrical drill bit body 10. The annular base 21 and the elastic claw body 22 are provided with through grooves, which together with the inner wall of the cylindrical cavity 13 form a water passage, which is connected to the inner port of the water hole 15.
[0047] During the drilling process, drilling fluid (e.g., water) needs to be pumped into the wellbore. In the core drill bit disclosed in this embodiment, the cylindrical drill bit body 10 can have multiple water holes 15, which are spaced apart along the circumference of the cylindrical drill bit body 10. The inner ports of the multiple water holes 15 are located on the inner wall of the cylindrical drill bit body 10 and below the core claw 20. The outer ports of the multiple water holes 15 are located on the outer wall of the cylindrical drill bit body 10. The annular base 21 and the elastic claw body 22 have through grooves, which, together with the inner wall of the cylindrical cavity 13, form a water passage, which communicates with the inner ports of the water holes 15.
[0048] Drilling fluid flows down from the main body 10 of the cylindrical drill bit through the water passage, then enters the inner ports of multiple water holes 15, and finally flows out from the outer ports of the multiple water holes 15, thus realizing the outflow of drilling fluid during drilling. Since the outer ports of the water holes 15 are located on the outer wall of the main body 10 of the cylindrical drill bit, the drilling fluid flowing out of the water holes 15 cannot be parallel to the drilling direction of the core drill bit. Under this condition, the drilling fluid will not directly scour the broken rock layers at the bottom of the well, thereby alleviating the situation where the broken rock layers are further fragmented, making core forming more difficult. This is beneficial to core forming and can improve the core recovery rate.
[0049] Specifically, in order to improve the uniformity of drilling fluid delivery, the plurality of water holes 15 can be evenly distributed in the circumferential direction of the cylindrical drill bit body 10.
[0050] The structure of the water eye 15 that meets the above requirements can be varied. For example, the water eye 15 can extend through the cylindrical drill bit body 10 along an arc or through the cylindrical drill bit body 10 in a zigzag extension manner. The embodiments of the present invention do not limit the specific shape of the water eye 15.
[0051] In one embodiment, the water inlet 15 may include a first water passage section 151 and a second water passage section 152. The first water passage section 151 and the second water passage section 152 are connected and extend at an angle. It should be noted that the angled extension means that both the first water passage section 151 and the second water passage section 152 are inclined relative to the drilling direction of the core drill bit.
[0052] The first port of the first water passage section 151 is the inner port of the water inlet 15. The second port of the first water passage section 151 is connected to the first port of the second water passage section 152, and the second port of the second water passage section 152 is the outer port of the water inlet 15. The junction of the first water passage section 151 and the second water passage section 152 is lower than the first port of the first water passage section 151 and also lower than the second port of the second water passage section 152. This structure of the water inlet 15 allows the drilling fluid to be sprayed in an obliquely upward direction during the downward drilling of the core drill bit. This further reduces the impact on the fractured formation on one side of the core drill bit's drilling direction, which is beneficial to core formation and thus improves the core recovery rate.
[0053] Based on the coring drill bit disclosed in the embodiments of the present invention, the present invention discloses a coring drilling device, the disclosed coring drilling device including the coring drill bit described in the above embodiments.
[0054] The embodiments of the present invention have been described above with reference to the accompanying drawings. However, the present invention is not limited to the specific embodiments described above. The specific embodiments described above are merely illustrative and not restrictive. Those skilled in the art can make many other forms under the guidance of the present invention without departing from the spirit and scope of the claims, and all of these forms are within the protection scope of the present invention.
Claims
1. A core drilling bit, characterized in that, The drill bit includes a cylindrical drill bit body (10) and a core claw (20); the cylindrical drill bit body (10) includes a drilling end (11), the annular end face of which is provided with cutting teeth (30) distributed along its circumference; the cylindrical cavity (13) of the cylindrical drill bit body (10) includes a conical space; the core claw (20) includes an annular base (21) and a plurality of elastic claw bodies (22) spaced apart along the circumference of the annular base (21); the annular base... (21) Attached to the inner wall of the conical space, the first end of the plurality of elastic claws (22) is connected to the annular base (21), and the second end of the plurality of elastic claws (22) forms a clamping space (23). The clamping space (23) is connected to the core inlet (14) of the drilling end (11). The second end of the plurality of elastic claws (22) is used to clamp the core that enters the clamping space (23) through the core inlet (14).
2. The core drill bit according to claim 1, characterized in that, The clamping space (23) includes a constant-diameter space (231) and a tapering space (232). The tapering space (232) is connected to the constant-diameter space (231) and is located between the core inlet (14) and the constant-diameter space (231). The large port of the tapering space (232) faces the core inlet (14), and the small port of the tapering space (232) is connected to the constant-diameter space (231). The central axis of the constant-diameter space (231) coincides with the central axis of the conical space and the central axis of the cylindrical cavity (13).
3. The core drill bit according to claim 1, characterized in that, The annular base (21) and the plurality of elastic claws (22) are an integral structure.
4. The core drill bit according to claim 1, characterized in that, The annular base (21) and the plurality of elastic claws (22) form a conical structure, wherein the surface of the conical structure facing the inner wall of the conical space is adapted to and in contact with the shape of the inner wall of the conical space.
5. The core drill bit according to claim 1, characterized in that, The core drill bit also includes a centering assembly (40), which includes a connecting sleeve (41) and a plurality of rolling elements (42). The connecting sleeve (41) is fixed inside the cylinder cavity (13) and located above the core claw (20). The plurality of rolling elements (42) are distributed along the circumferential direction of the connecting sleeve (41). The plurality of rolling elements (42) are embedded in the inner wall of the connecting sleeve (41), and part of the rolling surface is exposed and protrudes from the inner wall of the connecting sleeve (41).
6. The core drill bit according to claim 5, characterized in that, The connecting sleeve (41) is fixedly connected to the cylindrical drill bit body (10) by means of threaded connection.
7. The core drill bit according to claim 6, characterized in that, The straightening component (40) also includes at least one sealing ring (43), which is located between the connecting sleeve (41) and the cylindrical drill bit body (10) and tensions the connecting sleeve (41).
8. The core drill bit according to claim 1, characterized in that, The cylindrical drill bit body (10) has a plurality of water holes (15) spaced apart along the circumference of the cylindrical drill bit body (10). The inner ports of the plurality of water holes (15) are located on the inner wall of the cylindrical drill bit body (10) and below the core claw (20). The outer ports of the plurality of water holes (15) are located on the outer wall of the cylindrical drill bit body (10). The annular base (21) and the elastic claw body (22) have through grooves. The grooves and the inner wall of the cylindrical cavity (13) form a water passage, which is connected to the inner ports of the water holes (15).
9. The core drill bit according to claim 8, characterized in that, The water eye (15) includes a first water passage section (151) and a second water passage section (152) extending at an incline. The first port of the first water passage section (151) is the inner port of the water eye (15). The second port of the first water passage section (151) is connected to the first port of the second water passage section (152). The second port of the second water passage section (152) is the outer port of the water eye (15). The junction of the first water passage section (151) and the second water passage section (152) is lower than the first port of the first water passage section (151) and also lower than the second port of the second water passage section (152).
10. A core drilling device, characterized in that, The core drill bit includes any one of claims 1 to 9.