Mixed-set PDC core bit

Abstract

The present application relates to drilling equipment technical field, it is a kind of mixed inlay PDC coring bit, including drill bit body, first tooth group and second tooth group, drill bit body upper outer side is spaced apart and is uniformly distributed with several first blades along circumference, the open outward chip groove is formed between the adjacent two first blades and drill bit body, first tooth group and second tooth group are spaced apart and are arranged on each first blade upper outer side.The present application is reasonable and compact in structure, first tooth group is arranged at the side of first blade, second tooth group is arranged at the other side opposite to first tooth group of first blade, cutting tooth distribution is compact, can realize the continuous overlapping arrangement of multiple rows of teeth, the space between first tooth group and second tooth group is little waste, can maximize the space of first blade, reduce the width of first blade, to ensure the cross-sectional area of chip groove, to ensure enough space for the water channel of drill bit, so that the combination of first tooth group, second tooth group and third tooth group can improve the rock breaking rate of drill bit, enhance the sustained drilling capacity of drill bit.

Description

Technical Field

[0001] This invention relates to the field of drilling equipment technology, and is a hybrid PDC coring drill bit. Background Technology

[0002] The performance of core drilling bits directly affects the efficiency, quality, cost, and even safety of core drilling. Although small, drill bits are crucial tools for accelerating drilling and reducing costs. PDC (Polycrystalline Diamond Compact Bit) drill bits, playing a vital role in this process, have become the primary rock-breaking tool, gradually replacing roller cone bits. Nearly 80% of drilling footage is achieved using PDC drill bits, which have already established a dominant position in the oil drilling bit market.

[0003] Although PDC drill bits have many advantages and are widely used, they are less wear-resistant in hard formations compared to other drill bits. To improve the wear resistance of PDC drill bits, the tooth density is generally increased to extend their service life. Common methods include using double-row, triple-row, or other multi-row tooth structures.

[0004] Existing PDC drill bits with multi-row tooth arrangement often have a certain spacing between the front and rear rows of teeth to ensure the bonding strength of the front row. A body of a certain thickness is left between the front and rear rows to support the front row. However, if the spacing is too small, the strength will be insufficient; if the spacing is too large, it will occupy too much space, and tooth arrangement will be difficult due to the limitations of the drill bit size. Using multiple tooth rows will result in excessively wide cutter wings and narrow flow channels, restricting the bottomhole flow field and hydraulic structure. This significantly affects bottomhole cleaning and rock-carrying performance during drilling, increases the risk of mud buildup, and affects the drill bit's rock-breaking efficiency and service life. This problem is particularly pronounced in deep well drilling where the formation hardness is high, and for drill bits with smaller wellbore sizes. Summary of the Invention

[0005] This invention provides a hybrid PDC coring bit that overcomes the shortcomings of the prior art and effectively solves the problems of low drilling efficiency and short service life of existing coring bits in deep wells with difficult formations and rock breaking.

[0006] The technical solution of this invention is achieved through the following measures: A hybrid PDC coring drill bit includes a drill bit body, a first tooth group, and a second tooth group. A plurality of first cutting wings are evenly distributed circumferentially on the upper outer side of the drill bit body. Adjacent first cutting wings form an outward-opening chip removal groove with the drill bit body. Each first cutting wing has a first tooth group and a second tooth group spaced apart on its upper outer side. The first tooth group includes a plurality of rear cutting teeth fixed sequentially from top to bottom on the outer side of the first cutting wings. The second tooth group includes a plurality of front cutting teeth fixed sequentially from top to bottom on the outer side of the first cutting wings. On the outer side of each first cutting wing, the first tooth group... A gap is provided between one side and the first side of the front cutting tooth. The second side of the rear cutting tooth and the second side of the front cutting tooth extend into two adjacent chip removal grooves in a direction that is far apart from each other. A fan-shaped second cutting wing is fixed at the upper end of the drill body corresponding to each first cutting wing position. The outer end of each second cutting wing is smoothly transitioned to the upper end of the first cutting wing. At least two third tooth groups are provided at intervals from the inside to the outside at the upper end of each second cutting wing. An arc-shaped first top cutting tooth is fixed at the upper end of the second cutting wing between each two adjacent third tooth groups. The third tooth group includes several second top cutting teeth distributed at intervals along the circumference.

[0007] The following are further optimizations and / or improvements to the above-mentioned technical solution: The first blade can be provided with a fixing groove on the side away from the rear cutting tooth, and the front cutting tooth is fixed in the fixing groove.

[0008] Both the cross-section of the aforementioned fixed groove and the cross-section of the front cutting tooth can be circular, and the inclination angle of the front cutting tooth is 10 to 35 degrees.

[0009] The exposed height of the rear cutting tooth relative to the first blade can be less than or equal to the diameter of the front cutting tooth.

[0010] The exposed height of the front cutting tooth relative to the first blade is 1 to 3 mm higher than that of the rear cutting tooth relative to the first blade.

[0011] The cross-section of the aforementioned rear cutting tooth can be a V-shape with the opening facing inward, and the width of the rear cutting tooth is smaller than the diameter of the front cutting tooth.

[0012] The largest circle formed by the front cutting teeth on the outer side of the first blade is the cutting circle. The projections of the front and rear cutting teeth onto the cutting circle are located in an area beyond two-thirds of the diameter of the cutting circle.

[0013] Each of the two adjacent second cutter wings has a flushing hole at the upper end of the drill body that extends into the drill body at the lower end.

[0014] The number of front cutting teeth on the outer side of each of the first blades can be greater than or equal to 6.

[0015] The number of back cutting teeth on the outer side of each of the first blades can be greater than or equal to 8.

[0016] This invention features a rational and compact structure. The first tooth group is positioned on one side of the first cutter wing, and the second tooth group is positioned on the opposite side of the first cutter wing. The compact distribution of the cutting teeth allows for continuous overlapping of multiple rows of teeth, minimizing space waste between the first and second tooth groups. This maximizes the utilization of the space in the first cutter wing, reducing its width and ensuring sufficient cross-sectional area for the chip removal groove, thus providing ample space for the drill bit's water passages. The combination of the first, second, and third tooth groups enhances the drill bit's rock-breaking rate and continuous drilling capability. The cutting tooth structure of this invention improves the flexibility of drill bit tooth placement, saves tooth placement space, optimizes the drill bit's hydraulic structure, and increases rock-breaking and coring efficiency. It also enhances the strength, reliability, and service life of the drill bit's cutting teeth, further strengthening the drill bit's continuous drilling capability. Attached Figure Description

[0017] Appendix Figure 1 These are schematic diagrams of the main structure of embodiments one through nine of the present invention.

[0018] Appendix Figure 2 The diagram shows the top view of embodiments one through nine of the present invention.

[0019] Appendix Figure 3 This is a three-dimensional structural diagram of embodiments one through nine of the present invention.

[0020] Appendix Figure 4 For the appendix Figure 1 A magnified structural diagram of point A in the middle.

[0021] Appendix Figure 5 For the appendix Figure 3 A magnified structural diagram at point B in the middle.

[0022] The codes in the attached diagram are as follows: 1 is the drill bit body, 2 is the first cutter wing, 3 is the front cutting tooth, 4 is the rear cutting tooth, 5 is the chip removal groove, 6 is the second cutter wing, 7 is the first top cutting tooth, 8 is the second top cutting tooth, 9 is the guide block, 10 is the connecting block, 11 is the flushing hole, 12 is the first inner ring platform, 13 is the second inner ring platform, and 14 is the guide groove. Detailed Implementation

[0023] The present invention is not limited to the following embodiments, and the specific implementation can be determined according to the technical solution of the present invention and the actual situation.

[0024] In this invention, for ease of description, the description of the relative positions of the components is based on the appendix to the specification. Figure 1 The layout is described using a diagrammatic method, such as the positional relationships of front, back, top, bottom, left, and right, which are based on the instructions attached. Figure 1The orientation of the layout is determined by the direction of the map.

[0025] The present invention will be further described below with reference to embodiments and accompanying drawings: Example 1: As shown in the attached document Figures 1 to 5 As shown, the hybrid PDC core drill bit includes a drill body 1, a first tooth group, and a second tooth group. Several first blades 2 are evenly distributed circumferentially along the upper outer side of the drill body 1. Adjacent first blades 2 form outward-facing chip grooves 5 with the drill body 1. Each first blade 2 has a first tooth group and a second tooth group spaced apart on its upper outer side. The first tooth group includes several rear cutting teeth 4 fixed sequentially from top to bottom to the outer side of the first blade 2. The second tooth group includes several front cutting teeth 3 fixed sequentially from top to bottom to the outer side of the first blade 2. On the outer side of each first blade 2, the first side of the rear cutting tooth 4 and the front cutting tooth 3... The first side is spaced apart. The second side of the rear cutting tooth 4 and the second side of the front cutting tooth 3 extend into the two adjacent chip removal grooves 5 in a direction that is far apart from each other. The upper end of the drill body 1 corresponding to each position of the first blade 2 is fixed with a fan-shaped second blade 6. The outer end of each second blade 6 is smoothly transitioned to the upper end of the first blade 2. At least two third tooth groups are spaced from the inside to the outside on the upper end of each second blade 6. The upper end of the second blade 6 between each two adjacent third tooth groups is fixed with an arc-shaped first top cutting tooth 7. The third tooth group includes several second top cutting teeth 8 distributed circumferentially.

[0026] According to the requirements, the drill body 1 has a hollow structure. On the outer side of each first blade 2, there is a gap between the first side of the rear cutting tooth 4 and the first side of the front cutting tooth 3. The second side of the rear cutting tooth 4 and the second side of the front cutting tooth 3 extend into two adjacent chip removal grooves 5 in a mutually distancing direction. Taking the foremost first blade 2 as an example, there is a gap between the first side of the rear cutting tooth 4 and the first side of the front cutting tooth 3, that is, there is a gap between the right side of the rear cutting tooth 4 and the left side of the front cutting tooth 3. The second side of the rear cutting tooth 4 and the second side of the front cutting tooth 3 extend into two adjacent chip removal grooves 5 in a mutually distancing direction. That is, the left side of the rear cutting tooth 4 extends to the left into the chip removal groove 5 on the left side of the first blade 2, and the right side of the front cutting tooth 3 extends to the right into the chip removal groove 5 on the right side of the first blade 2.

[0027] A guide block 9 is fixed to the outer side of the drill body 1 below each first cutter wing 2. A spirally distributed connecting block 10 is fixed between the upper end of each guide block 9 and the lower side of the corresponding first cutter wing 2. The lower end of each guide block 9 is inclined to the outer side of the drill body 1. The guide block 9, the connecting block 10 and the first cutter wing 2 can be fixed together. In this way, the lower part of the chip removal groove 5 is spiral-shaped, the cross-section of the first top cutting tooth 7 is V-shaped with the opening facing downwards, and there is a gap between two adjacent second cutter wings 6. Each second cutter wing 6 has three third tooth groups spaced from the inside to the outside at its upper end. Each third tooth group includes three teeth spaced along the circumference. The second cutting tooth 8 has two circular cross-sections and one fan-shaped cross-section. The opening directions of the arc surfaces of the three second cutting teeth 8 in the three third tooth groups are different. When in use, the drill bit body 1 can quickly discharge impurities in the chip removal groove 5 when it rotates, preventing accumulation and blockage in the chip removal groove 5, which would affect the drilling efficiency of the drill bit. Along the drilling rotation direction of the drill bit body 1, the front cutting tooth 3 on the outer side of each first blade 2 is located in front of the rear cutting tooth 4. Between two adjacent chip removal grooves 5, the front side of the first blade 2 is located in front of the front side of the guide block 9.

[0028] The front cutting tooth 3, the rear cutting tooth 4, and the second top cutting tooth 8 are all made of PDC material, which improves the rock-breaking drilling efficiency of ultra-deep wells in difficult formations, extends service life, reduces the difficulty of coring in extremely hard formations, and can also meet the special coring operations of various well types.

[0029] During use, the first tooth group is positioned on one side of the first cutter wing 2, and the second tooth group is positioned on the opposite side of the first cutter wing 2. The cutting teeth are compactly distributed, enabling multiple rows of teeth to be continuously overlapped. There is minimal wasted space between the first and second tooth groups, maximizing the use of the space in the first cutter wing 2 and reducing its width. This ensures the cross-sectional area of ​​the chip removal groove 5, providing sufficient space for the drill bit's water passages. The combination of the first, second, and third tooth groups improves the drill bit's rock-breaking rate and enhances its continuous drilling capability. The cutting tooth structure of this invention improves the flexibility of drill bit tooth placement, saves tooth placement space, optimizes the drill bit's hydraulic structure, and improves the drill bit's rock-breaking and coring efficiency. It also improves the strength, reliability, and service life of the drill bit's cutting teeth, enhancing the drill bit's continuous drilling capability.

[0030] The above-mentioned mixed-lay PDC coring bits can be further optimized and / or improved according to actual needs: Example 2: As an optimization of the above examples, as shown in the appendix. Figure 1 , 3 As shown, the first blade 2 has a fixing groove on its side away from the rear cutting tooth 4, and the front cutting tooth 3 is fixed in the fixing groove.

[0031] The distance between the central axis of the fixing groove and the inner wall of the drill body 1 gradually increases in the direction away from the rear cutting tooth 4. Taking the first cutting wing 2 at the front as an example, the first cutting wing 2 is provided with a fixing groove on the right side. The distance between the central axis of the fixing groove and the inner wall of the drill body 1 gradually increases from left to right. The front cutting tooth 3 is fixed in the fixing groove. The installation method of the front cutting tooth 3 on the outside of the first cutting wing 2 is the known impregnation method. The PDC material front cutting tooth 3 is evenly distributed in a certain thickness layer on the working surface of the first cutting wing 2. As the first cutting wing 2 wears down, the PDC material front cutting tooth 3 is continuously exposed and continuously grinds the rock, and continuously sharpens itself.

[0032] Example 3: As an optimization of the above examples, as shown in the appendix. Figure 1 , 2 As shown in Figure 3, the cross-section of the fixed groove and the cross-section of the front cutting tooth 3 are both circular, and the inclination angle of the front cutting tooth 3 is 10 to 35 degrees.

[0033] The rake angle refers to the angle between the cutting surface of the front cutting tooth 3 and the normal to the drill bit cutting profile at the radial position of the front cutting tooth 3. During use, this improves the overall formation penetration performance of the drill bit and the efficiency of core drilling. Depending on the requirements, the cross-section of the front cutting tooth 3 can also be stepped axial.

[0034] Example 4: As an optimization of the above examples, as shown in the appendix. Figure 1 , 2 As shown in Figures 3 and 4, the exposed height of the rear cutting tooth 4 relative to the first blade 2 is less than or equal to the diameter of the front cutting tooth 3.

[0035] The exposed height of the rear cutting tooth 4 relative to the first blade 2 is less than or equal to the diameter of the front cutting tooth 3, that is, the vertical distance between the outermost end of the rear cutting tooth 4 and the corresponding outer side of the first blade 2 is less than or equal to the diameter of the front cutting tooth 3.

[0036] In operation, with this configuration, the PDC rear cutting tooth 4 is continuously overlapped with the first side of the PDC front cutting tooth 3. The PDC rear cutting tooth 4 serves as the rear support for the PDC front cutting tooth 3. Since the hardness and rigidity of the PDC cutting tooth are significantly higher than those of the drill bit body 1, the support strength of the PDC rear cutting tooth 4 is far greater than that of the drill bit body 1 in conventional tooth arrangement. Therefore, the rear support strength of the PDC front cutting tooth 3 is significantly higher than that of the front row of teeth in a conventional drill bit, which is beneficial for improving the tooth retention reliability and service life of the drill bit's cutting teeth.

[0037] Example 5: As an optimization of the above examples, as shown in the appendix. Figure 1 , 2 As shown, the exposed height of the front cutting tooth 3 relative to the first blade 2 is 1 to 3 mm higher than the exposed height of the rear cutting tooth 4 relative to the first blade 2.

[0038] As required, the vertical distance between the upper end of the first top cutting tooth 7 and the upper end of the second blade 6 is less than the distance between the upper end of the second top cutting tooth 8 and the upper end of the second blade 6. During use, this arrangement allows the front cutting tooth 3 to protect the rear cutting tooth 4. If the front cutting tooth 3 is damaged or worn, the rear cutting tooth 4 can directly serve as a replacement, supplementing and assisting the front teeth, thereby enhancing the drill bit's continuous drilling capability.

[0039] Example 6: As an optimization of the above examples, as shown in the appendix Figure 1 , 3 As shown, the cross-section of the rear cutting tooth 4 is a V-shape with the opening facing inward, and the width of the rear cutting tooth 4 is smaller than the diameter of the front cutting tooth 3.

[0040] During use, the PDC front cutting tooth 3 and the PDC rear cutting tooth 4 are distributed on the two sides of the first blade 2. The PDC front cutting tooth 3 and the PDC rear cutting tooth 4 are not connected. The multiple rows of teeth on the outside of the drill bit body 1 are continuously overlapped. There is no wasted space between the front and rear rows of teeth, which can maximize the use of the drill bit space, reduce the blade width, and leave enough space for the water channel setting of the drill bit.

[0041] Example 7: As an optimization of the above examples, as shown in the appendix. Figure 1 , 3 As shown in Figure 5, the largest circle formed by the front cutting teeth 3 on the outer side of the first blade 2 is the cutting circle, and the projections of the front cutting teeth 3 and the rear cutting teeth 4 onto the cutting circle are located in the area beyond two-thirds of the diameter of the cutting circle.

[0042] During use, this configuration enhances the drill bit's ability to penetrate different geological formations, maximizing the advantages of this invention.

[0043] Example 8: As an optimization of the above examples, as shown in the appendix Figure 2 , 3 As shown in Figures 5 and 6, each of the two adjacent second blades 6 has a flushing hole 11 at the upper end of the drill body 1, with the lower end extending into the drill body 1.

[0044] According to requirements, a first inner ring platform 12 is fixed to the inner side of the upper end of the drill bit body 1, and a second cutter wing 6 is fixed to the upper end of the first inner ring platform 12. A second inner ring platform 13 is fixed to the inner side of the upper part of the drill bit body 1 corresponding to the lower end of the first inner ring platform 12. The diameter of the inner ring surface of the first inner ring platform 12 is smaller than the diameter of the inner ring surface of the second inner ring platform 13. The cross-section of the flushing hole 11 is oblong, and the lower end of the flushing hole 11 extends downward so that a guide groove corresponding to the flushing hole 11 and opening inward is formed on the inner ring surface of the second inner ring platform 13. That is, the upper end of the guide groove is connected to the lower end of the flushing hole 11. During use, by setting the flushing hole 11, the liquid in the drill bit body 1 can flow out from the flushing hole 11 and then discharge the impurities in the chip removal groove 5, avoiding the blockage of the chip removal groove 5.

[0045] Example 9: As an optimization of the above examples, as shown in the appendix Figure 1 , 3 As shown, the number of front cutting teeth 3 on the outer side of each first blade 2 is greater than or equal to 6; the number of rear cutting teeth 4 on the outer side of each first blade 2 is greater than or equal to 8.

[0046] According to the requirements, the number of front cutting teeth 3 on the outer side of each first blade 2 is 6 to 10, and the number of rear cutting teeth 4 on the outer side of each first blade 2 is 8 to 10. When the tooth density of the front cutting teeth 3 and the rear cutting teeth 4 is increased, the thickness of the first blade 2 can be reduced. In this way, while ensuring the strength of the drill bit, the first blade 2 can be machined according to a certain arc to ensure the flow channel area.

[0047] The above technical features constitute various embodiments of the present invention, which have strong adaptability and implementation effect. Unnecessary technical features can be added or removed according to actual needs to meet the needs of different situations.

Claims

1. A hybrid PDC coring drill bit, characterized in that... The drill bit includes a drill body, a first tooth group, and a second tooth group. Several first cutter wings are evenly distributed circumferentially on the upper outer side of the drill body. Adjacent first cutter wings form outward-opening chip removal grooves with the drill body. Each first cutter wing has a first tooth group and a second tooth group spaced apart on its upper outer side. The first tooth group includes several rear cutting teeth fixed sequentially from top to bottom to the outer side of the first cutter wings. The second tooth group includes several front cutting teeth fixed sequentially from top to bottom to the outer side of the first cutter wings. On the outer side of each first cutter wing, a [missing information - likely a design feature] is provided between the first side surface of the rear cutting teeth and the first side surface of the front cutting teeth. The second side of the rear cutting tooth and the second side of the front cutting tooth are spaced apart and extend into two adjacent chip removal grooves in a direction that is far apart from each other. A fan-shaped second cutting wing is fixed on the upper end of the drill body corresponding to each first cutting wing position. The outer end of each second cutting wing is smoothly transitioned to the upper end of the first cutting wing. At least two third tooth groups are provided at intervals from the inside to the outside on the upper end of each second cutting wing. An arc-shaped first top cutting tooth is fixed on the upper end of the second cutting wing between each two adjacent third tooth groups. The third tooth group includes several second top cutting teeth distributed at intervals along the circumference.

2. The hybrid PDC coring drill bit according to claim 1, characterized in that... The first blade has a fixing groove on its side away from the rear cutting tooth, and the front cutting tooth is fixed in the fixing groove.

3. The hybrid PDC coring drill bit according to claim 2, characterized in that... Both the cross-section of the fixed groove and the cross-section of the front cutting tooth are circular, and the inclination angle of the front cutting tooth is 10 to 35 degrees.

4. The hybrid PDC coring drill bit according to claim 3, characterized in that... The exposed height of the rear cutting tooth relative to the first blade is less than or equal to the diameter of the front cutting tooth; Or / and, the exposed height of the front cutting tooth relative to the first blade is 1 to 3 mm higher than the exposed height of the rear cutting tooth relative to the first blade.

5. The hybrid PDC coring drill bit according to claim 3 or 4, characterized in that... The cross-section of the rear cutting tooth is V-shaped with the opening facing inward, and the width of the rear cutting tooth is smaller than the diameter of the front cutting tooth.

6. The hybrid PDC coring drill bit according to claim 1, 2, 3, or 4, characterized in that... The largest circle formed by the front cutting teeth on the outer side of the first blade is the cutting circle. The projections of the front and rear cutting teeth onto the cutting circle are located in the area beyond two-thirds of the diameter of the cutting circle.

7. The hybrid PDC coring drill bit according to claim 5, characterized in that... The largest circle formed by the front cutting teeth on the outer side of the first blade is the cutting circle. The projections of the front and rear cutting teeth onto the cutting circle are located in the area beyond two-thirds of the diameter of the cutting circle.

8. The hybrid PDC coring drill bit according to claim 1, 2, 3, 4, or 7, characterized in that... Each adjacent pair of second cutter wings has a flushing hole at the upper end of the drill body that extends into the drill body at the lower end; Or / and, the number of front cutting teeth on the outer side of each first blade is greater than or equal to 6; Or / and, the number of back cutting teeth on the outer side of each first blade is greater than or equal to 8.

9. The hybrid PDC coring drill bit according to claim 5, characterized in that... Each adjacent pair of second cutter wings has a flushing hole at the upper end of the drill body that extends into the drill body at the lower end; Or / and, the number of front cutting teeth on the outer side of each first blade is greater than or equal to 6; Or / and, the number of back cutting teeth on the outer side of each first blade is greater than or equal to 8.

10. The hybrid PDC coring drill bit according to claim 6, characterized in that... Each adjacent pair of second cutter wings has a flushing hole at the upper end of the drill body that extends into the drill body at the lower end; Or / and, the number of front cutting teeth on the outer side of each first blade is greater than or equal to 6; Or / and, the number of back cutting teeth on the outer side of each first blade is greater than or equal to 8.

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