PDC drill bit capable of preventing transverse vibration

Abstract

The invention provides a PDC drill bit capable of preventing transverse vibration, and belongs to the technical field of well drilling tools, the PDC drill bit comprises a drill bit body and a drill bit connector, a plurality of cutting teeth including main cutting teeth and gauge protection cutting teeth are distributed on a blade of the drill bit body, the main cutting teeth are arranged on the inner side part of the blade, the gauge protection cutting teeth are arranged on the peripheral part of the blade, and the main cutting teeth and the gauge protection cutting teeth are arranged on the drill bit body. The main cutting teeth are arranged on a single blade in an up-down staggered mode capable of preventing transverse vibration, annular concave-convex grooves can be formed between the spaced cutting teeth while the cutting teeth are arranged on the whole crown shape, the annular concave-convex grooves can be clamped with rock at the well bottom in the drilling process, and transverse vibration of the drill bit is avoided. According to the drill bit, the cutting teeth originally arranged on the crown curve are arranged in the up-down staggered mode, the complete crown shape is reserved, meanwhile, concave-convex grooves can be formed between the cutting teeth, the drill bit can be perfectly clamped with rock at the well bottom in the drilling process, and transverse vibration of the drill bit is avoided.

Description

Technical Field

[0001] The present invention relates to the technical field of drilling tools, particularly to the technical field of PDC bits, and specifically to a PDC bit for preventing lateral vibration. Background Art

[0002] A polycrystalline diamond compact (PDC) bit, i.e., a PDC bit, as an important tool for oil and gas development, directly affects the drilling speed, drilling quality, and drilling cost. However, during the operation of a PDC bit, lateral vibration may occur due to the quality of the bit itself, formation characteristics, or drilling parameters, thereby reducing the service life of the bit. In severe cases, it may lead to the fracture of the cutter blades during drilling and the bit can no longer be used. The lateral vibration affects the overall drilling efficiency and increases the usage cost of the bit and the maintenance cost of the wellbore.

[0003] If the cutting edges of a PDC bit are not precisely machined during the manufacturing process, resulting in inconsistent lengths, angles, or wear degrees of each cutter blade, it will cause imbalance. Uneven material distribution inside the bit or deviation in the installation position of the PDC teeth will change the center of gravity position of the bit. During drilling, the bit with a shifted center of gravity is like an unbalanced rotating body and will generate centrifugal force. This centrifugal force will periodically change direction as the bit rotates, causing the bit to vibrate in the lateral direction.

[0004] The real formation is often composed of various different rock types and structures. When the bit enters a hard formation from a soft formation or encounters a hard interlayer in the formation, the hardness difference between different formations will cause a sudden change in the cutting resistance. For example, when drilling in a soft formation, the cutting force is small, and when encountering a hard interlayer, the cutting force will suddenly increase. This uneven cutting resistance acting on the bit will cause the bit to vibrate in the lateral direction. Structures such as bedding and fractures in the formation will also affect the drilling stability of the bit. If the bit drills along the bedding direction and encounters areas with interlaced bedding or developed fractures, the direction of the cutting force of the bit will be disturbed, easily causing lateral deviation and thus triggering vibration.

[0005] Some rocks have significant differences in physical properties (such as hardness, elastic modulus, etc.) in different directions. This anisotropy will cause different cutting effects of the bit in different directions. For example, when drilling in a shale formation with obvious anisotropy, the cutting resistance and cutting mode of the bit are different in the direction perpendicular to the shale bedding and in the direction parallel to the shale bedding, which easily causes the bit to generate lateral vibration.

[0006] When the drill bit rotates at too high a speed, the centrifugal force will increase significantly. Due to the structural characteristics of the PDC drill bit, excessive centrifugal force will cause the blade of the drill bit to bear greater force in the lateral direction, resulting in lateral vibration of the drill bit. Moreover, at high rotation speeds, the drill bit cuts the formation faster, and when encountering formation unevenness, it is more likely to cause vibration. When the drilling pressure is too high, the drill bit will over-cut into the formation. On the contrary, too low drilling pressure will reduce the cutting efficiency of the drill bit, and it is easy to slip and swing during drilling, which will also cause lateral vibration.

[0007] Conventional tooth arrangement methods cannot avoid the lateral vibration of the drill bit, which will interfere with the normal cutting trajectory of the drill bit and prevent it from continuously and stably crushing the rock. The drill bit will sometimes deviate from the predetermined drilling direction and needs to be constantly adjusted to continue drilling, which makes the drilling process intermittent, resulting in a significant decrease in drilling efficiency. The lateral vibration of the PDC drill bit will cause the drilled wellbore to deviate from the designed trajectory, resulting in problems such as increased well inclination and dogleg. This is extremely unfavorable for subsequent casing lowering and completion operations, because the casing needs to be lowered along the regular wellbore. If the wellbore trajectory deviation is too large, it may make it difficult to lower the casing or fail to reach the predetermined position smoothly, affecting the quality of the entire wellbore and the safety of subsequent mining operations. Summary of the invention

[0008] Based on the above engineering background, the present invention aims at the deficiencies in the prior art and provides a PDC drill bit that is resistant to lateral vibration, which can maintain a better wellbore trajectory during the drilling process, improve the drilling effect and reduce the possibility of drill bit damage.

[0009] A PDC drill bit for preventing lateral vibration comprises a drill bit body and a drill bit joint, wherein a plurality of blades are arranged on the drill bit body, and a plurality of cutting teeth are arranged on the blades, including main cutting teeth and gauge cutting teeth, wherein the main cutting teeth are arranged on the inner part of the blades, and the gauge cutting teeth are arranged on the outer peripheral part of the blades; the number of the main cutting teeth on a single blade is not less than 7, and the main cutting teeth are arranged in an up-and-down staggered form on a single blade to prevent lateral vibration, and while the cutting teeth are arranged on the entire crown shape, annular concave-convex grooves can be formed between the spaced cutting teeth, which can be stuck with the bottom hole rock during drilling to prevent the drill bit from generating lateral vibration.

[0010] Furthermore, the cutting teeth of the drill bit are staggered up and down along a direction perpendicular to the straight line segment in the straight line segment, and are staggered up and down along a line connecting the crown top or the center direction of the outer cone in the arc segment.

[0011] Furthermore, the cutting teeth on the same blade may be the same or different in size, so that the concave-convex grooves of different layers have different depths and groove shapes.

[0012] Furthermore, when using cutting teeth of a single size on the same blade, in soft formations, larger-sized cutting teeth need to be used, with the cutting tooth diameter not less than 19 mm and the height difference between adjacent teeth more than 8 mm; in hard or heterogeneous formations, smaller cutting teeth need to be used, with the cutting tooth diameter not exceeding 19 mm and the height difference between adjacent teeth being 2 - 8 mm.

[0013] Furthermore, when using cutting teeth of different sizes on the same blade, under the same tooth arrangement conditions, the size of the concave and convex grooves is adjusted by the size of different teeth, that is, one size of tooth is set in the groove part, and another size of tooth is set in the protruding part, so that the sizes of the teeth in the concave and convex grooves are different; the sizes of the teeth within the same groove part are the same, and the sizes of the teeth within the same protruding part are the same.

[0014] Furthermore, in hard formations, the cutting teeth in the concave part are larger than those in the convex part, with the cutting tooth diameter not exceeding 19 mm. Therefore, the exposure amount is small, the impact resistance is good, and the distribution pattern is that small cutting teeth protrude outward and large cutting teeth are concave inward; in soft formations, the cutting teeth in the concave part are smaller than those in the convex part, with the cutting tooth diameter not less than 19 mm. Therefore, the exposure amount is large and the drilling speed is high, and the distribution pattern is that small cutting teeth are concave inward and large cutting teeth protrude outward.

[0015] Further, the order of staggering the cutting teeth up and down is set according to requirements. The combination of adjacent cutting teeth staggered up and down is one up and one down as a combination, or two up and two down as a combination, or three up and three down as a combination, which is selected according to the size of the drill bit or the size of the teeth; Using different numbers as a group needs to be based on the formation environment. When the formation is a soft formation, a combination of one up and one down with fewer teeth is used as the tooth arrangement pattern; when the formation is a hard formation, a combination of three up and three down with more teeth is used as the tooth arrangement pattern; when the formation is a hard formation, a combination of two up and two down or three up and three down with more teeth is used as the tooth arrangement pattern; when the formation is a heterogeneous formation, a combination of two up and two down with teeth is used as the tooth arrangement pattern.

[0016] Further, the cutting teeth use special-shaped cutting teeth, and the special-shaped teeth include but are not limited to: triangle, rectangle, semi-circle.

[0017] Further, the arrangement of multiple cutting teeth near the wellbore is fixed on the crown curve, or a smaller movement amount is used, with the movement amount not exceeding one-third of the vertical staggering distance of other teeth, so that it can be tangent to the wellbore. For example, if the staggering distance in other areas is 3 mm, the staggering distance here does not exceed 1 mm. Of course, according to the actual situation, this data can be adjusted again to ensure tangency with the wellbore and not exceed the size of the wellbore.

[0018] The present invention has the following advantages: 1. Through the staggered tooth arrangement method, it can perfectly engage with the bottom-hole rock during drilling, avoiding the lateral vibration of the drill bit, enabling it to continuously and stably break the rock, improving the service life and rock-breaking efficiency of the drill bit, and saving time and economic costs.

[0019] 2. By the way of staggered tooth arrangement, the lateral vibration caused by the processing quality of the drill bit itself or when facing formations such as hard interlayers is offset, enabling it to move in a predetermined direction, avoiding problems such as well deviation and increased dogleg severity, and ensuring the quality of the entire wellbore and the safety of subsequent operations such as exploitation.

[0020] 3. By the way of staggered tooth arrangement, the cutting teeth are formed into layers, and the higher cutting teeth participate in rock breaking first. At this time, the higher cutting teeth have a strong ability to penetrate into the rock, and the rock-breaking efficiency is relatively high.

[0021] 4. By the way of staggered tooth arrangement, the centrifugal force caused by too high rotational speed and the lateral vibration caused by too large or too small drilling pressure are avoided, making the drilling process more efficient and convenient, and reducing the operation difficulty.

[0022] 5. Different tooth arrangement forms are adopted, such as staggered one by one, staggered two by two, etc., so as to be used in different formation environments, and uneven grooves with different depths can be obtained, thereby giving the anti-vibration effect suitable for the drilling requirements of the formation. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 It is a schematic diagram of the radial tooth arrangement of the present invention; Figure 2 It is a schematic diagram of the structure of the PDC drill bit of the present invention; Figure 3 It is a schematic diagram of the radial tooth arrangement of each blade of the present invention, and the order is the first blade, the second blade, the third blade, the fourth blade, and the fifth blade in sequence; Figure 4 For Figure 3 the schematic diagram of the structure of the radial tooth arrangement of the first main blade in Figure 5 It is a schematic diagram of the structure of the blade breaking rock of the present invention; Figure 6 It is a schematic diagram of the radial tooth arrangement of the blade with different staggering methods of the present invention; Figure 7 It is a schematic diagram of the radial tooth arrangement of each blade of the present invention with different sizes of cutting teeth; Figure 8 It is a schematic diagram of the radial tooth arrangement with different sizes of cutting teeth of the present invention; Figure 9Schematic diagram of the structure of a PDC bit with different sizes of cutting teeth for the present invention; Figure 10 Schematic diagram of the radial tooth arrangement of each blade with different staggering combinations for the present invention; Figure 11 Schematic diagram of the radial tooth arrangement with different staggering combinations for the present invention; Figure 12 Schematic diagram of the structure of a PDC bit with different staggering combinations for the present invention; Figure 13 Schematic diagram of the radial tooth arrangement of each blade of a conventional bit; Figure 14 Finite element simulation results of the present invention; Figure 15 Finite element simulation results of a conventional bit.

[0024] In the figure: 1 - Main cutting tooth; 2 - Bit body; 3 - Gauge cutting tooth; 4 - Nozzle; 5 - Blade; 6 - Rock profile; 7 - Bit sub. Detailed implementation manners

[0025] The following further illustrates the present invention in conjunction with embodiments. It should be noted that in this article, words such as "upper" and "lower" are only used for conveniently describing the drawings, and do not limit the directions in actual use, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the term "comprising", "including" or any other variant thereof is intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements not only includes those elements, but also includes other elements not expressly listed, or further includes elements inherent to such process, method, article or device.

[0026] The following describes the specific description manner of the present invention in conjunction with the drawings.

[0027] Embodiment 1:

[0028] As Figures 1 - 2 shown, a PDC bit for preventing lateral vibration includes a bit body 2 and a main cutting tooth 1. A plurality of blades are evenly distributed on the bit body, and nozzles 4 are provided between the blades. The tooth arrangement method of the bit cutting teeth adopts an upper and lower staggered arrangement. While maintaining the complete crown shape, concave and convex grooves can be formed between the cutting teeth, which can perfectly engage with the bottom rock during drilling to avoid lateral vibration of the bit.

[0029] In this embodiment, the bit size is 8 1 / 2 inches, and there are a total of 29 main cutting teeth on all 5 blades. The size of the main cutting teeth is selected as 15.88 mm. Among them, a total of 15 teeth on different teeth have the same moving direction, all concave towards the bit; a total of 11 teeth on different teeth have the same moving direction, all convex towards the outside of the bit. 3 main cutting teeth 1 are arranged on the crown curve, that is, as shown on the right side of Figure 1 The main cutting teeth 1 in the part just entering the vertical plane need to be kept at a position similar to that of the gauge cutting teeth 3 to avoid the cutting depth of other main cutting teeth 1, which will cause increased wear.

[0030] Specifically, in this embodiment, in the first blade, 3 are concave and 3 are convex; in the second blade, 2 are concave and 2 are convex, and one is regularly arranged on the crown curve; in the third blade, 3 are convex and 3 are concave; in the fourth blade, 2 are concave and 2 are convex, and one is regularly arranged on the crown curve; in the fifth blade, 2 are concave and 2 are convex, and one is regularly arranged on the crown curve.

[0031] As Figure 3 shown, the cutting teeth on each blade are arranged in an up-and-down manner. While ensuring that there are cutting teeth on the crown curve, the cutting teeth on each blade are staggered so that they are stuck in the rock, avoiding lateral vibration. The moving direction of each tooth is as Figure 4 shown. The moving direction of the straight line segment is to move along the direction perpendicular to the straight line segment, and the moving direction of the arc segment is to move along the connection direction of the crown top or the center of the outer cone.

[0032] In this embodiment, the moving distance is 4 mm. Such a designed moving amount is to most accurately adapt to the size of 15.88 mm to obtain the best groove depth, so as to ensure the anti-vibration effect without affecting the drilling efficiency. The three-dimensional drawing is as Figure 2 Since the cutting teeth move outwards by a certain amount, there will be more parts of the cutting teeth outside the blade. To avoid the phenomenon of cutting teeth falling off during drilling, a base for the cutting teeth is reserved on the blade, and chamfering treatment is carried out at the same time. At the same time, to avoid excessive wear of the last upward moving cutting teeth on each blade, as mentioned above, the arrangement of these cutting teeth is on the crown curve.

[0033] Embodiment 2:

[0034] When using cutting teeth of a single size on the same blade 1, in soft formations, larger cutting teeth need to be used, with a cutting tooth diameter of not less than 19 mm and a height difference between adjacent teeth of more than 8 mm; in hard or heterogeneous formations, smaller cutting teeth need to be used, with a cutting tooth diameter of not exceeding 19 mm and a height difference between adjacent teeth of 2 - 8 mm. The definition of hard or soft formations is defined by the operation block itself. For example, a drillability extreme value of 5 < Kd ≤ 7 is classified as a hard formation, and a formation with Kd less than 5 is considered a soft formation.

[0035] Example 3:

[0036] When using cutting teeth of different sizes on the same blade 1, under the same tooth arrangement conditions, the size of the concave and convex grooves is adjusted by the size of different teeth, that is, one size of tooth is set in the groove part and another size of tooth is set in the protruding part, so that the sizes of the teeth in the concave and convex grooves are different; the sizes of the teeth within the same groove part are the same, and the sizes of the teeth within the same protruding part are the same.

[0037] In hard formations, the cutting teeth in the concave part are larger than those in the convex part, with a cutting tooth diameter of not exceeding 19 mm. Therefore, the exposure amount is small, the impact resistance is good, and the distribution pattern is that small cutting teeth protrude outward and large cutting teeth are concave inward; in soft formations, the cutting teeth in the concave part are smaller than those in the convex part, with a cutting tooth diameter of not less than 19 mm. Therefore, the exposure amount is large, the drilling speed is high, and the distribution pattern is that small cutting teeth are concave inward and large cutting teeth protrude outward.

[0038] Example 4:

[0039] Based on Example 1, the order of the cutting teeth above and below each blade can be randomly combined. For example, the first cutting tooth can be selected to be concave or convex, but after the first cutting tooth is determined, the subsequent cutting teeth need to be stagger - arranged according to the setting. For example, Figure 6 As shown, the staggering order of each blade is different from that in Example 1. While ensuring that there are cutting teeth on the crown curve, the cutting teeth on each blade are staggered. In Figure 6 , the movement amount of the cutting teeth on each blade is 4 mm, the size of the main cutting teeth is 15.88 mm, and the movement direction is the same as that in Example 1.

[0040] Example 5:

[0041] Based on Example 1 or 2, the moving distance of the main cutting tooth 1 is an adjustable structure, which is set according to the required exposure height. Specifically, different - sized cutting teeth can be used or different distances can be moved. For example, Figure 7 and Figure 8As shown, in these two figures, cutting teeth of 13.44 mm and 15.88 mm are used, and by using them in combination, the distance between the convex teeth and the concave teeth can be adjusted.

[0042] Example 6:

[0043] In addition, on the basis of Example 1, the combination of the movement of the cutting teeth on each blade can be one up and one down as a combination. In this embodiment, two up or two down is a combination, as Figure 10 and Figure 11 shown.

[0044] In this embodiment, there are 24 main cutting teeth in total. 6 groups of 12 teeth are concave towards the drill bit, and 6 groups of 12 teeth are convex towards the drill bit. The moving distance of the cutting teeth is 3 mm. Two cutting teeth on each blade are a combination, two up and two down. In this embodiment, 15.88 mm main cutting teeth are used, and at the same time, the tooth density is reduced. Compared with Example 1, one cutting tooth is reduced on each blade. While ensuring that each cutting tooth has enough installation space, the size of the convex and concave grooves can be adjusted. It is also possible to use cutting teeth of different sizes to adjust the distance of the convex and concave grooves as in Example 3.

[0045] Example 7:

[0046] Use the Figure 2 drill bit and a conventional drill bit for a simulation experiment. The tooth arrangement of the conventional drill bit is the same as that of the Figure 2 drill bit, the difference being that the cutting teeth of the conventional drill bit are not moved up and down, and the cutting teeth are arranged on the crown curve, as Figure 13 shown. Under the same drilling pressure and drilling speed, the set drilling pressure is 50000 N, the drilling speed is 9.41 rad / s, the rocks drilled are all granite, the experimental time is 10 seconds, and the other experimental conditions are also the same. After sorting out the experimental results, the data from 6 s to 10 s are selected. At this time, both drill bits have basically drilled into the rock, and the data are more reasonable and stable compared with the data in the previous few seconds. At the same time, since the displacements of the X and Y directions of the drill bit need to be fixed when setting the boundary conditions, we look at the stability of the drill bit from the reaction force of the drill bit.

[0047] As Figure 14 and Figure 15The curves showing the variation of the reaction forces of the anti-lateral vibration bit and the conventional bit with time are presented respectively. It can be seen from the figure that: the curve of the anti-lateral vibration bit fluctuates relatively less, indicating that the range of variation of the reaction force during its operation is relatively narrow and its stability is better; the curve of the conventional bit fluctuates greatly, showing that the range of variation of the reaction force during its operation is wider and its stability is poor. The reaction force value of the anti-lateral vibration bit fluctuates relatively regularly within a certain range; the reaction force value of the conventional bit changes more frequently and with a larger amplitude, and there are more occurrences of larger peaks and valleys. From the curves, the working state of the anti-lateral vibration bit is relatively stable and can better cope with vibrations and other conditions during the drilling process; the influence of factors such as vibrations on the reaction force of the conventional bit during operation is greater, and its working state is relatively unstable.

[0048] Within 10 s, the displacement of the anti-lateral vibration bit in the Z direction is 89.478 mm, and the displacement of the conventional bit in the Z direction is 71.9942 mm. The anti-lateral vibration bit has reached 71.99 mm at 9.05 s. Therefore, the drilling can save about 10% of the drilling time.

[0049] It can be seen from the above simulation results that the anti-lateral vibration bit designed by the present invention can effectively avoid the lateral vibration of the bit during the drilling process, has better stability, helps to improve the stability of the bit at the bottom of the well, and reduces vibrations and offsets.

[0050] The above are only the preferred embodiments of the present invention and do not impose any form of limitation on the present invention. Although the present invention has been disclosed as above with the preferred embodiments, it is not intended to limit the present invention. Any person skilled in the art can make some changes or modifications to the above-disclosed technical content to obtain equivalent embodiments with equivalent changes within the scope of the technical solution of the present invention. Any simple modification, equivalent change and modification made to the above embodiments based on the technical essence of the present invention without departing from the content of the technical solution of the present invention still fall within the scope of the technical solution of the present invention.

Claims

1. A PDC drill bit for preventing lateral vibration, characterized in that: The drill bit comprises a drill body (2) and a drill bit joint (7), wherein a plurality of blades (5) are provided on the drill bit body (2), and a plurality of cutting teeth are arranged on the blades (5), including main cutting teeth (1) and gauge cutting teeth (3), wherein the main cutting teeth (1) are arranged on the inner part of the blades (1), and the gauge cutting teeth (3) are arranged on the outer peripheral part of the blades (1); the number of the main cutting teeth (1) on a single blade is not less than 7, and the main cutting teeth (1) are arranged on a single blade (5) in an up-and-down staggered manner to prevent lateral vibration, and while the cutting teeth are arranged on the entire crown shape, an annular concave-convex groove can be formed between the spaced cutting teeth, so that the cutting teeth can be stuck with the bottom rock during the drilling process, thereby preventing the drill bit from generating lateral vibration.

2. A PDC drill bit for preventing lateral vibration according to claim 1, characterized in that: The drill bit cutting teeth move up and down and stagger along a direction perpendicular to the straight line segment in the straight line segment, and move up and down and stagger along a line connecting the crown top or the center direction of the outer cone in the arc segment.

3. A PDC drill bit for preventing lateral vibration according to claim 2, characterized in that: The cutting teeth on the same blade (5) may be of the same or different sizes, so that the concave-convex grooves of different layers have different depths and groove shapes.

4. A PDC drill bit for preventing lateral vibration according to claim 3, characterized in that: When a single-sized cutting tooth is used on the same blade (1), in soft formations, a larger cutting tooth needs to be used, the cutting tooth diameter is not less than 19 mm, and the height difference between adjacent teeth is more than 8 mm; in hard formations or inhomogeneous formations, a smaller cutting tooth needs to be used, the cutting tooth diameter does not exceed 19 mm, and the height difference between adjacent teeth is 2 to 8 mm.

5. A PDC drill bit for preventing lateral vibration according to claim 4, characterized in that: When cutting teeth of different sizes are used on the same blade (1), under the same tooth arrangement condition, the size of the concave-convex groove is adjusted by the size of the different teeth, that is, teeth of one size are arranged in the concave portion, and teeth of another size are arranged in the convex portion, so that the teeth of the concave-convex groove have different sizes; the size of the teeth in the same concave portion is the same, and the size of the teeth in the same convex portion is the same.

6. A PDC drill bit for preventing lateral vibration according to claim 5, characterized in that: In hard formations, the size of the cutting teeth in the concave part is larger than that in the convex part, and the diameter of the cutting teeth does not exceed 19 mm. Therefore, the exposed amount is small and the impact resistance is good, and the distribution pattern is that the small cutting teeth are convex outward and the large cutting teeth are concave inward; in soft formations, the size of the cutting teeth in the concave part is smaller than that in the convex part, and the diameter of the cutting teeth is not less than 19 mm. Therefore, the exposed amount is large and the drilling speed is high, and the distribution pattern is that the small cutting teeth are concave inward and the large cutting teeth are convex outward.

7. The PDC drill bit for preventing lateral vibration according to claim 2, characterized in that: The order of staggering the cutting teeth up and down is set according to the required situation. The combination of adjacent staggered cutting teeth up and down is one up and one down as one combination, or two up and two down as one combination, or three up and three down as one combination, which can be selected according to the size of the drill bit or the size of the teeth; Using different numbers as a group depends on the environment of the stratum. When the stratum is a soft stratum, a combination of one up and one down with a smaller number of teeth is adopted as the tooth layout pattern; when the stratum is a hard stratum, a combination of three up and three down with a larger number of teeth is adopted as the tooth layout pattern; when the stratum is a hard stratum, a combination of two up and two down or three up and three down with a larger number of teeth is adopted as the tooth layout pattern; when the stratum is a heterogeneous stratum, a combination of two up and two down is adopted as the tooth layout pattern.

8. The PDC drill bit for preventing lateral vibration according to claim 2, characterized in that: The cutting teeth are special-shaped cutting teeth, and the special-shaped teeth include but are not limited to: triangle, rectangle, and semicircle.

9. The PDC drill bit for preventing lateral vibration according to claim 2, characterized in that: The arrangement of multiple cutting teeth of the cutting teeth close to the well wall is fixed on the crown curve, or a smaller movement is adopted, which does not exceed one-third of the staggered vertical spacing of other teeth, so that it can be tangent to the well wall.

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