CN117432340B - A high specific pressure PDC drill bit - Google Patents

Abstract

The invention relates to a high specific pressure PDC drill bit, belonging to the technical field of drilling equipment. Pressure blade group, the high specific pressure blade group includes a main cutting blade and at least one co-rail cutting blade, and the radial position of the co-rail cutting teeth installed on the co-rail cutting blade is consistent with the main cutting blade of the same group. The radial position deviation Pv of the main cutting teeth installed on the blade ranges from ‑0.5r to 0.5r, where r is the radius of the main cutting teeth. The invention allows the cutting teeth on the main cutting blade to take on the work of cutting rocks, thereby enhancing the specific pressure on the single tooth and enhancing the aggressiveness of the drill bit. At the same time, the co-orbital cutting blades are responsible for auxiliary tasks such as increasing contact points, pre-crushing, and auxiliary rock breaking, thereby increasing the stability, impact resistance and wear resistance of the drill bit. As a result, the high specific pressure PDC drill bit has strong aggressiveness and high stability.

Description

A high specific pressure PDC drill bit

Technical Field

The invention relates to a high specific pressure PDC drill bit, belonging to the technical field of drilling equipment.

Background Art

PDC drill bits are also called fixed blade drill bits because the main cutting structure of the drill bit is a blade structure that is relatively fixed to the drill bit body. There are many ways to fix the blade, and the most commonly used method is the blade that is integrated with the drill bit body. But no matter how the fixing form changes, the main cutting element of the PDC drill bit is still the PDC cutting teeth installed and welded on the blade tooth holes. When the drilling pressure acts on the drill bit, the drill bit body transfers the drilling pressure to the PDC cutting teeth. Multiple PDC cutting teeth are pressed into the rock together and move in a circle around the drill bit with the drill bit, thereby scraping the rock. Therefore, under the same drilling pressure, increasing the drilling pressure ratio on a single tooth, the deeper the cutting teeth are pressed into the rock, and from a phenomenon point of view, the drill bit has a stronger ability to eat into the rock.

In the prior art, the penetration capacity of drill bits with different numbers of blades is different. Therefore, designers usually design drill bits with different numbers of blades according to the lithology of the formation. From the design principle, when the number of blades exceeds four, conventional technology will be equipped with long blades and short blades at the same time. The main function of the short blade is to increase the tooth density of the nose and shoulder of the drill bit, thereby increasing the wear resistance of the drill bit. At the same time, the more blades there are, the more contact points the drill bit has with the bottom of the rock well, that is, the more support points there are, and it is easier to maintain the balance of the drill bit. Therefore, in conventional designs, three-blade drill bits are usually designed for shallow layers, and seven-blade or eight-blade drill bits are usually designed for deep abrasive formations. The purpose of this design is to choose the advantages and disadvantages of different numbers of blades, three blades for their aggressiveness, and eight blades for their stability and wear resistance. But relatively speaking, along with the high aggressiveness of the three-blade drill bit, the three-blade drill bit is unstable when drilling, the wellbore quality is low, and the drill bit life is short. Problems also plague construction personnel. Similarly, when drilling in complex and difficult-to-drill formations, the eight-blade drill bit exhibits strong wear resistance and stability, but also exhibits problems such as low specific pressure, slow drilling speed, and long drilling time.

The essence of the above problem lies in the design method of the drill bit. The cutting teeth on all blades of a conventional drill bit participate in the full-coverage design of the bottom hole, which means that each blade is responsible for the cutting work and the drilling pressure is shared by all the cutting teeth on each blade. Under the same drilling pressure, the more blades involved in cutting, the greater the tooth density, the more cutting teeth that break the rock, the higher the stability, the smaller the drilling pressure allocated to a single cutting tooth, and the lower the aggressiveness; conversely, the fewer blades involved in cutting, the smaller the tooth density, the fewer cutting teeth that break the rock, the lower the stability, the higher the drilling pressure allocated to a single cutting tooth, and the greater the aggressiveness. Therefore, in conventional drill bits, how to have both high aggressiveness and high stability is an urgent problem to be solved.

Summary of the invention

Aiming at the problem that conventional drill bits in the prior art are difficult to have both high aggressiveness and high stability, the present invention provides a high specific pressure PDC drill bit.

The technical solution of the present invention for solving the above technical problems is as follows: a high specific pressure PDC drill bit, comprising a joint and a drill bit body, wherein the joint is fixedly connected to one end of the drill bit body, and at least two groups of high specific pressure blade groups are distributed along the circumferential direction at the other end of the drill bit body, wherein the high specific pressure blade groups include a main cutting blade and at least one co-track cutting blade, and the radial position deviation Pv of the co-track cutting teeth installed on the co-track cutting blade and the radial position deviation Pv of the main cutting teeth installed on the main cutting blade of the same group is in the range of -0.5r to 0.5r, wherein r is the radius of the main cutting tooth, that is, the range of the co-track offset band is -0.5r-0.5r.

Here, the definitions of the co-track cutting blades and co-track cutting teeth in the high-ratio pressure blade group are explained in detail. In the top view of the drill bit, the drill bit rotates around the central axis of the drill bit, and the center of the main cutting tooth on the main cutting blade is used as the base point. The circle formed by one rotation of the drill bit is the reference ring, and the radially inward position bias of the reference ring is a negative value, and the maximum is -0.5r, that is, the co-track deviation value Pv is negative and the maximum is -0.5r; the radially outward position bias of the reference ring is a positive value, and the maximum is 0.5r, that is, the co-track deviation value Pv is positive and the maximum is 0.5r. The range of Pv thus forms a co-track offset band for the main cutting tooth. If the center of the cutting tooth on the co-track cutting blade rotates a certain angle, and the trajectory arc formed is within the range of the above-mentioned co-track offset band, it can be considered as the co-track cutting tooth of the main cutting tooth to which the co-track offset band belongs. If at least one cutting tooth on the same-track cutting wing is within the same-track offset band of the cutting teeth on the main cutting wing, that is, if there is at least one same-track cutting tooth on the same-track cutting wing, then the same-track cutting wing and the main cutting wing can be called a high-pressure blade wing group of the same group.

On the basis of the above technical solution, the present invention can also be improved as follows:

The number of main cutting teeth installed on the main cutting blade meets and , where N represents the number of main cutting blades, ni is the number of main cutting teeth on the i-th main cutting blade, r is the radius of the main cutting teeth, and _R is the radius of the drill bit. This setting can not only form full coverage of the bottom of the well, but also ensure that each main cutting blade has sufficient strength.

Furthermore, in the high specific pressure blade group, the same-track cutting blade is arranged in the clockwise or counterclockwise direction along the circumference of the main cutting blade.

Furthermore, the tooth arrangement envelopes of the main cutting blade and the same-track cutting blade are overlapped or offset, and the offset distance d satisfies: -0.2r≤d≤0.2r.

Furthermore, the cutting teeth on the same track cutting blade are arranged at the radial peripheral part of the drill bit.

Furthermore, the radial tooth arrangement starting position of the same-track cutting blade is within the range of 0.25R-0.8R, where R is the radius of the drill bit.

Furthermore, the main cutting teeth on the main cutting blade are wide-edge teeth.

Furthermore, the on-track cutting teeth on the on-track cutting blade are non-planar teeth.

Furthermore, the main cutting blade is provided with double or multiple rows of cutting teeth, and/or the same-track cutting blade is provided with double or multiple rows of cutting teeth.

Furthermore, the number of blades in blade groups with different high specific pressures on the same drill bit is different.

Compared with the prior art, the present invention has the following beneficial effects:

1) This application sets a high specific pressure blade group, uses main cutting blades and co-track cutting blades to cooperate, sets a smaller number of main cutting blades, increases the specific pressure of the main cutting teeth, and improves the aggressiveness of the drill bit; sets co-track cutting blades to increase the contact area between the drill bit and the rock, prevents the drill bit from becoming unstable, and increases the stability of the drill bit. On the other hand, the co-track cutting blades increase the number of blades of the drill bit for the entire drill bit, thereby increasing the number of contact points between the drill bit and the bottom of the well, further ensuring that the drill bit maintains a high stability during the drilling process, and the co-track cutting teeth on the co-track cutting blades will not consume the specific pressure of the main cutting teeth on the main cutting blades of the same group, so the aggressiveness of the drill bit will not be reduced due to the addition of co-track cutting blades. On the contrary, the presence of co-track cutting teeth means that the PDC content of the entire drill bit is higher than that of a drill bit without co-track cutting teeth, and the rock formation needs to wear away more PDC materials before the drill bit fails. The phenomenon reflected in the project is that the life of the drill bit has been significantly increased.

2) By setting the co-track deviation value Pv range of the co-track cutting teeth installed on the co-track cutting blade and the corresponding main cutting teeth installed on the main cutting blade of the same group within -0.5r to 0.5r, the auxiliary cutting function of the co-track cutting teeth can be limited, so that the drill bit as a whole has aggressiveness and stability. Within this deviation range, a reasonable deviation distance can be adjusted to meet the engineering needs of different formations.

3) By setting the radial tooth layout starting position of the same-track cutting blade within the range of 0.25R-0.8R, the cutting teeth on the same-track cutting blade are arranged on the radial outer part of the drill bit, which can make it bear more wear, enhance the wear resistance of the drill bit, extend its service life, and increase the contact points on the radial outer part of the drill bit, effectively reducing the polygonal effect during drilling, increasing the stability of the drill bit, and at the same time having strong aggressiveness.

4) By aligning the tooth envelopes of the main cutting blade and the co-track cutting blade or setting the offset distance within the range of -0.2r to 0.2r, the wear degree of the co-track cutting teeth or the main cutting teeth can be reduced while ensuring the aggressiveness and stability of the drill bit.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG1 is a schematic diagram of a high specific pressure PDC drill bit of the present invention;

FIG2 is a top view of a high specific pressure PDC drill bit of the present invention;

FIG3 is a schematic diagram of radial tooth arrangement of a high specific pressure PDC drill bit of the present invention;

FIG4 is a schematic diagram of a seventh embodiment of a high specific pressure PDC drill bit of the present invention;

FIG5 is a schematic diagram of an eighth embodiment of a high specific pressure PDC drill bit of the present invention;

FIG6 is a schematic diagram of a ninth embodiment of a high specific pressure PDC drill bit according to the present invention;

FIG7 is a schematic diagram of a high specific pressure PDC drill bit according to a tenth embodiment of the present invention;

FIG8 is a schematic diagram of a high specific pressure PDC drill bit according to a twelfth embodiment of the present invention;

FIG9 is a schematic diagram of a high specific pressure PDC drill bit according to a thirteenth embodiment of the present invention;

FIG10 is a schematic diagram of a high specific pressure PDC drill bit according to a fourteenth embodiment of the present invention;

FIG11 is a schematic diagram of a fifteenth embodiment of a high specific pressure PDC drill bit of the present invention;

FIG12 is a schematic diagram of a high specific pressure PDC drill bit according to a sixteenth embodiment of the present invention;

In the figure, 1, joint; 2, drill body; 3, high specific pressure blade group; 4, center axis of drill bit; 31, main cutting blade; 32, same track cutting blade; 311, main cutting tooth; 321, same track cutting tooth; 312, reference arc; 322, circular track of same track cutting tooth; 323, same track offset zone; 314, radial tooth layout envelope of main cutting blade; 324, radial tooth layout envelope of same track cutting blade; 315, The tooth crown line of the main cutting blade; 325, the tooth crown line of the same track cutting blade; 316, the first backup tooth; 326, the second backup tooth; Pv is the same track deviation value; R is the radius of the drill bit; r is the radius of the main cutting tooth; d is the offset distance between the radial tooth envelope line of the same track cutting blade and the radial tooth envelope line of the main cutting blade; Inp is the radial tooth starting position of the same track cutting blade; A is the inner cone angle of the crown of the drill body.

DETAILED DESCRIPTION

In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, the specific embodiments of the present invention are described in detail below in conjunction with the accompanying drawings. In the following description, many specific details are set forth to facilitate a full understanding of the present invention. However, the present invention can be implemented in many other ways different from this description, and those skilled in the art can make similar improvements without violating the connotation of the present invention, so the present invention is not limited by the specific embodiments disclosed below.

Unless otherwise defined, all technical and scientific terms used herein have the same meaning as those commonly understood by those skilled in the art of the present invention. The terms used in the specification of the present invention are only for describing specific embodiments and are not intended to limit the present invention.

As shown in FIG1 , a high specific pressure PDC drill bit includes a joint 1 and a drill body 2. The joint 1 is fixedly welded to one end of the drill body 2. The other end of the drill body 2, i.e., the top of the drill bit, is circumferentially distributed with at least two groups of high specific pressure blade groups 3. The high specific pressure blade group 3 is composed of a main cutting blade 31 and at least one co-track cutting blade 32. The main cutting blade 31 is mainly responsible for rock breaking, and a plurality of main cutting teeth 311 are distributed on the main cutting blade 31. The co-track cutting blade 32 is mainly responsible for auxiliary work, and at least one co-track cutting tooth 321 is distributed on the co-track cutting blade 32. By setting a smaller number of main cutting blades 31, the specific pressure of the main cutting teeth 311 is increased, so that the performance of the main cutting teeth 311 in eating into the rock is enhanced, and the aggressiveness of the drill bit is improved. By setting the co-track cutting blade 32, the contact area between the drill bit and the rock is increased, the drill bit is prevented from being unstable, and the stability of the drill bit is increased. At the same time, the setting of the same track cutting teeth 321 increases the number of PDC cutting teeth of the entire drill bit, that is, increases the PDC material content of the drill bit, which can greatly improve the wear resistance of the drill bit. The main cutting blade 31 and the same track cutting blade 32 form a high specific pressure blade group 3, which can greatly exert the advantages of high aggressiveness and high stability.

The radius of the main cutting tooth 311 and the radius of the co-track cutting tooth 321 can be set to be consistent or inconsistent. When the radius of the co-track cutting tooth 321 is larger than the radius of the main cutting tooth 311, the diamond equivalent of the cutting teeth on the co-track cutting blade 32 increases while the number remains unchanged, thereby increasing the wear resistance of the drill bit; when the radius of the co-track cutting tooth 321 is smaller than the radius of the main cutting tooth 311, the contact length between the cutting teeth on the co-track cutting blade 32 and the rock is reduced, thereby reducing the specific pressure borne by the co-track cutting blade 32, thereby increasing the specific pressure of the main cutting blade 31 and enhancing the aggressiveness of the drill bit. When the two are equal, the drill bit has both wear resistance and aggressiveness, but because the radii of the co-track cutting tooth 321 and the main cutting tooth 311 are the same, the shape of the rock groove ring formed by cutting the rock just matches, thereby improving the stability of the drill bit.

As shown in Figures 1 and 2, the drill bit rotates around the central axis 4 of the drill bit, with the center of the main cutting tooth 311 on the main cutting blade 31 as the base point, and the main cutting tooth 311 forms a circular track as the drill bit rotates one circle. A section of the circular arc track is shown in Figures 1 and 2, which is defined as the reference arc 312; with the center of the same track cutting tooth 321 on the same track cutting blade 32 as the base point, the circular track 322 of the same track cutting tooth is formed as the drill bit rotates. The radial distance between the reference arc 312 and the circular track 322 of the matching same track cutting tooth is the same track deviation value Pv.

The circular track 322 of the co-track cutting tooth is offset to a negative value inwardly in radial direction relative to the reference arc 312, which is defined as the co-track deviation value Pv is negative, and the maximum value is -0.5r, where r is the radius of the main cutting tooth 311; the circular track 322 of the co-track cutting tooth is offset to a positive value in radial direction relative to the reference arc 312, which is defined as the co-track deviation value Pv is positive, and the maximum value is 0.5r. Thus, the co-track offset zone 323 of the main cutting tooth 311 is formed. It is worth noting that when there are multiple co-track cutting blades 32 in a set of high-ratio pressure blade groups 3, a main cutting tooth 311 may have matching co-track cutting teeth 321 on multiple co-track cutting blades 32. The co-track deviation value Pv of the co-track cutting tooth 321 matching the main cutting tooth 311 can be 0, at which time the two are completely co-track, but the co-track cutting teeth 321 in the range of -0.5r to 0.5r can match the main cutting tooth 311. If the center of the cutting tooth on the same-track cutting blade 32 rotates a certain angle, and the resulting trajectory arc is within the above-mentioned same-track offset band 323, it can be considered as the same-track cutting tooth 321 of the main cutting tooth 311 to which the same-track offset band 323 belongs. In other words, the same-track cutting blade 32 has at least one same-track cutting tooth 321. The same-track deviation value Pv range of the same-track cutting tooth 321 installed on the same-track cutting blade 32 and the corresponding main cutting tooth 311 installed on the same group of main cutting blade 31 is -0.5r to 0.5r, and the same-track deviation value Pv range is a limitation on the auxiliary cutting function of the same-track cutting tooth 321. The positive and negative signs of the same-track deviation value Pv only indicate the direction of the radial inward deviation and the radial outward deviation. The larger the absolute value of the deviation, the stronger the auxiliary cutting function of the same-track cutting tooth 321, and the more specific pressure is shared. But relatively speaking, the specific pressure on the corresponding main cutting tooth 311 decreases, which leads to a decrease in the specific pressure of the main cutting blade 31, and the aggressiveness of the entire drill bit decreases, while the stability increases. The smaller the absolute value of the deviation is, the smaller the specific pressure shared by the same-track cutting tooth 321 is, the greater the specific pressure of the main cutting tooth 311 is, the aggressiveness of the entire drill bit increases, and the stability decreases. When the deviation value is equal to 0, the same-track cutting tooth 321 does not have an auxiliary cutting function, but only plays a role in enhancing stability and wear resistance. At this time, the aggressiveness of the drill bit is the strongest. Therefore, a reasonable deviation distance within the above-mentioned deviation range can be set to meet the engineering needs of different strata. When the same-track deviation value Pv of the same-track cutting tooth 321 is greater than 0.5r or less than -0.5r, it means that the same-track cutting tooth 321 is radially offset inward or outward by more than 0.5r relative to the matching main cutting tooth 311. The contact arc length between the same-track cutting tooth 321 and the rock increases, and it bears a larger cutting amount. The effect of the same-track cutting is weakened and transformed into the main cutting effect, which may break the original balanced design of the main cutting tooth arrangement, resulting in reduced stability of the drill bit and thus premature failure.

The coverage of the cutting teeth is usually designed to form a full coverage of the bottom of the well with the cutting teeth on all blades, and each blade has the function of main cutting. However, such an arrangement will make the drill bit's tooth density larger, the specific pressure on a single tooth lower, and the aggressiveness of the drill bit lower. Conventional methods will increase the drilling pressure allocated to a single blade by reducing the blade, but this setting will aggravate the polygonal effect of the drill bit, reduce the stability of the drill bit, and increase the impact load on the drill bit. The present invention adopts the design of a high specific pressure blade group 3, and divides the blade into a main cutting blade 31 and a co-track cutting blade 32. On the one hand, only the main cutting teeth 311 on the main cutting blade 31 are fully covered at the bottom of the well. From the perspective of the cutting teeth that bear the cutting function, this reduces the tooth density, increases the specific pressure of the cutting teeth, and enhances the aggressiveness of the drill bit; on the other hand, since the co-track cutting teeth 321 on the co-track cutting blade 32 hardly bear the cutting function, but can increase the diamond content of the drill bit and the contact point between the drill bit and the rock, the polygonal effect of the drill bit is weakened and the stability of the drill bit is enhanced. Specifically, the cutting teeth installed on the main cutting blade 31 can form full coverage of the well bottom, that is, meet the requirements of , where N represents the number of blades, ni _is the number of cutting teeth on the i-th main cutting blade 31, r is the radius of the main cutting tooth 311, and R is the radius of the drill bit. The sum of the radii of all the main cutting teeth 311 must be at least greater than or equal to the drill bit radius to ensure that the rocks at all positions on the bottom of the well are broken by cutting teeth. At the same time, in order to ensure that each main cutting blade 31 has sufficient strength, the total number of main cutting teeth 311 is set to That is, the cutting teeth on the same blade cannot be too close, otherwise interference will occur, or there is too little drill body material between the two teeth, resulting in insufficient strength and easy tooth loss during operation.

As shown in FIG3 , a schematic diagram of radial tooth arrangement of the present invention is shown. The radial tooth arrangement envelope 324 of the same-track cutting blade coincides with or is offset from the radial tooth arrangement envelope 314 of the main cutting blade, and the offset distance d satisfies: -0.2r≤d≤0.2r. When the offset distance is equal to -0.2r, the same-track cutting teeth 321 on the same-track cutting blade 32 first eat into the rock, causing pre-crushing of the bottom of the well, and the drill bit has the strongest aggressiveness. When the offset distance d is equal to 0, the radial tooth arrangement envelope 324 of the same-track cutting blade coincides with the radial tooth arrangement envelope 314 of the main cutting blade, and at this time the main cutting teeth 311 and the same-track cutting teeth 321 contact the bottom of the well at the same time, and the drill bit has the strongest stability. As the offset distance d increases, it reaches a maximum of 0.2r, which means that the main cutting teeth 311 only contact the rock after the same-track cutting teeth 321 eat into the rock to a depth of 0.2r, and the specific pressure is mainly borne by the main cutting teeth 311, and at this time the drill bit has a stronger aggressiveness. From the tooth crown line 315 of the main cutting blade and the tooth crown line 325 of the same track cutting blade, the radial tooth starting position Inp of the same track cutting blade 32 is within the range of 0.25R-0.8R. It can be seen that the cutting teeth on the same track cutting blade 32 are arranged in the radial peripheral part of the drill bit. This is because the radial peripheral part has a large radius of gyration and a long cutting distance in one rotation, which makes the cutting teeth very easy to wear. Arranging the same track cutting teeth 321 in the peripheral part can bear more wear, enhance the wear resistance of the drill bit, and extend the service life. In addition, such an arrangement increases the contact points of the radial periphery of the drill bit, effectively reduces the polygonal effect during the drilling process, and increases the stability of the drill bit. The crushing of the core rock is mainly borne by the main cutting teeth 311, so relatively speaking, the main cutting blade 31 is a long blade, and the same track cutting blade 32 is a short blade. When the radial tooth arrangement starting position of the same-track cutting blade 32 is 0.25R, the same-track cutting blade 32 is the longest, and the wear resistance is greatly enhanced on the basis of slightly stronger stability; when the radial tooth arrangement starting position of the same-track cutting blade 32 is 0.8R, the same-track cutting blade 32 is the shortest, and the aggressiveness is greatly enhanced on the basis of slightly weaker stability. The length of the same-track cutting blade 32 can be adjusted according to different formation lithology and working conditions to balance the aggressiveness and wear resistance of the drill bit. When Inp is less than 0.25R, the track cutting blade 32 is close to the center of the drill bit, so that the flow channel between the track cutting blade 32 and the adjacent main cutting blade 31 is narrow, which is not conducive to the discharge of cuttings; when Inp is greater than 0.8R, from the perspective of tooth arrangement design, this is already the position where the outer shoulder transitions to the diameter protection. Although cutting teeth can be arranged from this position in conventional design to increase wear resistance, the track cutting blade 32 loses the track auxiliary cutting and increased stability functions of the track cutting teeth 321. The main cutting teeth 311 from the cone part to the nose and then to the shoulder of the drill bit are all pre-supported and matched track cutting teeth 321, which can enable the main cutting teeth 311 to obtain the auxiliary function of the track cutting teeth 321 while bearing high specific pressure, which is beneficial to extend the life of the drill bit.

Preferably, the inner cone angle of the radial tooth arrangement envelope 314 of the main cutting blade of the high specific pressure blade group 3, that is, the inner cone angle A of the crown of the drill bit body, is in the range of 150-180°. The small inner cone angle range is adopted to give full play to the high specific pressure advantage of the main cutting blade 31, so that the main cutting teeth 311 at the center are easier to bite into the rock, and the excess drilling pressure is distributed to the external main cutting teeth 311, thereby increasing the specific pressure of the external main cutting teeth 311, and ultimately improving the overall aggressiveness of the drill bit.

Preferably, the co-track cutting blade 32 of the high specific pressure blade group 3 is arranged in the clockwise or counterclockwise direction along the circumference of the main cutting blade 31 to form a double blade group. When the co-track cutting blade 32 is arranged in the clockwise direction along the circumference of the main cutting blade 31, the main cutting blade 31 is in front of the co-track cutting blade 32 in the direction of travel, and the rock within the same co-track offset band 323 first contacts the main cutting tooth 311 on the main cutting blade 31, and the co-track cutting blade 32 mainly plays a role in improving the stability and wear resistance of the drill bit. When the on-track cutting wing 32 is arranged in the counterclockwise direction along the circumference of the main cutting wing 31, the on-track cutting wing 32 is in front of the main cutting wing 31 in the moving direction, and the rock within the same on-track offset band 323 first contacts the cutting teeth on the on-track cutting wing 32, thereby reducing the impact of the rock on the main cutting wing 31, indirectly enhancing the impact resistance of the main cutting teeth 311, but also reducing the aggressiveness of the drill bit to a certain extent.

Preferably, the main cutting blade 31 of the high specific pressure blade group 3 is provided with a same-track cutting blade 32 along the clockwise or counterclockwise direction of the circumference to form a three-blade group or a multi-blade group. There are many variations in the arrangement of the three-blade group or the multi-blade group. Taking the three-blade group as an example, it includes a main cutting blade 31 and two same-track cutting blades 32. When the two same-track cutting blades 32 are arranged in the clockwise direction of the main cutting blade 31 along the circumference, the polygonal effect of the drill bit is lower, the stability is stronger, and the aggressiveness is stronger. When the two same-track cutting blades 32 are arranged in the counterclockwise direction of the main cutting blade 31 along the circumference, the polygonal effect of the drill bit is lower, the stability is stronger, the aggressiveness is weakened, and the impact resistance is enhanced. When two co-track cutting wings 32 are arranged with the main cutting wing 31 in between, the co-track cutting wing 32 arranged along the clockwise direction of the main cutting wing 31 mainly plays a role in enhancing stability and wear resistance, while the co-track cutting wing 32 arranged along the counterclockwise direction of the main cutting wing 31 mainly plays a role in enhancing stability and impact resistance.

Usually, the spacing angle between blades directly considers the flow path distance between adjacent blades. In the present invention, the top of the drill bit includes at least two groups of high-pressure blade groups 3. In order to make the same-track cutting blades 32 and the main cutting blades 31 in the same group achieve a good same-track cutting effect and prevent the same-track cutting teeth 321 from being repeatedly broken, compared with conventional drill bits, the present invention needs to consider the blade spacing within the same high-pressure blade group 3. Assuming that there are multiple groups of high-pressure blade groups 3 with different numbers of blades on the same drill bit, the blade spacing angle range within each high-pressure blade group 3 should be recalculated, that is, the spacing angles of the internal blades are different between different high-pressure blade groups 3. When a high pressure blade group 3 has multiple blades 32 for cutting on the same track, the interval angle range between each blade in the same high pressure blade group 3 is 288°/(N·N _in )<a<540°/(N·N _in ), where N represents the number of high pressure blade groups 3, and N _in represents the number of blades in a high pressure blade group 3. This range is set to ensure that there is enough flow channel space between the blades for chip removal, and the unbalanced force of the drill bit can be optimized by adjusting the interval between the blades, so that the drill bit runs more smoothly. At the same time, this range will not cause the flow channel to be too narrow to form drill bit mud bags, nor will it interfere with other high pressure blade groups 3 due to too large intervals. This is different from the method of dividing 360° by the total number of drill blades in the conventional setting, in terms of design principle. When a＜288°/（N·N _in ）, the blades in the same high specific pressure blade group 3 are too close to each other, which may cause repeated chip removal due to untimely chip removal, affect the stability of same-track cutting and increase the wear of the drill bit. When a＞540°/（N·N _in ）, the blade spacing in the same high specific pressure blade group 3 is too large, which aggravates the polygonal effect of the drill bit, increases the vibration of the drill bit, increases the impact on the drill bit, and may cause abnormal failure of the drill bit.

It is further preferred that the number of blades of different high-specific-pressure blade wing groups 3 on the drill bit is different. For example, the drill bit has two high-specific-pressure blade wing groups 3, one double blade wing group and one triple blade wing group, the main cutting blade 31 of the double blade wing group is provided with the same-track cutting blade 32 along the clockwise direction of the circumference, and the main cutting blade 31 of the triple blade group is provided with the same-track cutting blade 32 along the clockwise and counterclockwise directions of the circumference. Such a setting can selectively balance or improve the stability and aggressiveness of the drill bit by adjusting the number of blades.

Preferably, the main cutting teeth 311 on the main cutting blade 31 are wide-blade teeth. The high specific pressure tooth edge of the wide-blade teeth is used to enhance the aggressiveness of the drill bit. In addition, the flat edge of the wide-blade teeth makes the cutting teeth in line contact with the rock, and the contact line is a straight line, which basically coincides with the crown curve. A small number of wide-blade teeth within the same radial range of the crown can achieve full coverage of the bottom of the well, further increasing the specific pressure on a single tooth. In fact, cutting teeth with similar wide-blade structures can also increase the aggressiveness of the drill bit to a certain extent. For example, large obtuse-angle teeth or large-curvature tooth-blade teeth or ridge-shaped wide-blade teeth. Large obtuse-angle teeth and large-curvature tooth-blade cutting teeth are suitable for installation at the outer shoulder position of the drill bit, so as to approach the curvature of the outer shoulder position of the crown curve, thereby obtaining a high specific pressure. Ridge-shaped wide-blade teeth are suitable for complex and heterogeneous formations or interlayers. The buffering effect of the ridge surface is used to improve the impact resistance of the main cutting teeth 311, and the wide tooth edge is used to improve the aggressiveness of the drill bit.

Preferably, the same-track cutting teeth 321 on the same-track cutting blade 32 are non-planar teeth. Different non-planar teeth are selected according to different formation environments. For example, in heterogeneous formations and soft and hard interlaced formations, ridge-shaped non-planar teeth (roof teeth, Mercedes teeth) are selected to make the contact between the working surface of the cutting teeth and the rock a continuous process, thereby improving the impact resistance of the drill bit. For another example, in abrasive formations, wedge-shaped teeth or conical teeth are selected to increase the diamond content of the cutting teeth, thereby improving the wear resistance of the drill bit.

Preferably, the cutting teeth on the main cutting blade 31 can be arranged in double rows or multiple rows. Specifically, the first backup teeth 316 are arranged in the rear row of the main cutting teeth 311. The first backup teeth 316 can be arranged in one row or multiple rows. The beneficial effect is to increase the diamond composite sheet of the main cutting blade 31, thereby increasing the diamond content and extending the life of the main cutting blade 31.

Preferably, the cutting teeth on the same track cutting blade 32 can be set to double rows or multiple rows. Specifically, the second backup teeth 326 are arranged in the rear row of the same track cutting teeth 321. In this way, the contact points between the cutting teeth on the same track cutting blade 32 and the rock are increased, and the stability of the drill bit is increased. On this basis, the same track cutting teeth 321 and the second backup teeth 326 can be set to different offset distances d to balance the auxiliary cutting function and the function of maintaining stability of the same track cutting blade 32, so that the same track cutting blade 32 has more comprehensive performance. At the same time, the same track cutting teeth 321 and the second backup teeth 326 can also use different cutting tooth shapes. For example, the same track cutting teeth 321 on the same track cutting blade 32 use ridge teeth to increase the impact resistance of the same track cutting blade 32, and the second backup teeth 326 use wedge teeth to enhance the wear resistance of the same track cutting blade 32, so that the same track cutting blade 32 has more comprehensive performance.

Based on the above features, implementation schemes with specific beneficial effects are described in conjunction with the following examples.

Embodiment 1: As shown in FIG1 , this is an implementation scheme of a high pressure ratio PDC drill bit, the radius R of the drill bit is 107.95 mm, the radius r of the main cutting tooth 311 is 6.72 mm, and single-row flat round teeth are arranged on the main cutting blade 31 and the co-track cutting blade 32. Three groups of high pressure ratio blade groups 3 are distributed circumferentially on the top of the drill bit, and each group of high pressure ratio blade groups 3 consists of a main cutting blade 31 and a co-track cutting blade 32. The co-track cutting blade 32 is arranged in the clockwise direction along the circumference of the main cutting blade 31. The radial position deviation (co-track deviation Pv) of the co-track cutting tooth 321 installed on the co-track cutting blade 32 and the radial position deviation of the main cutting tooth 311 installed on the main cutting blade 31 of the same group is 0. The radial tooth layout envelope 314 of the main cutting blade coincides with the radial tooth layout envelope 324 of the co-track cutting blade. The radial tooth arrangement starting position Inp of the same-track cutting blade 32 is at 32.385 mm. The beneficial effect of this solution is that the main cutting blade 31 is in front of the same-track cutting blade 32 in the direction of travel, and the rock within the same same-track offset band 323 first contacts the main cutting teeth 311 on the main cutting blade 31. The same-track cutting blade 32 mainly plays a role in improving the stability and wear resistance of the drill bit.

Embodiment 2: The difference between this solution and embodiment 1 is that the radial position of the track cutting teeth 321 installed on the track cutting blade 32 and the track deviation Pv of the main cutting teeth 311 on the same group of main cutting blade 31 is -3.36mm. This solution increases the rock breaking effect of the track cutting teeth 321 by increasing the track deviation Pv, reduces the cutting effect of the main cutting teeth 311, and reduces the specific pressure on the main cutting teeth 311, thereby making the drill bit slightly less aggressive, but relatively more stable and more wear-resistant.

Embodiment 3: The difference between this solution and embodiment 1 is that the radial position of the co-track cutting tooth 321 installed on the co-track cutting blade 32 and the co-track deviation Pv of the main cutting tooth 311 on the same group of main cutting blade 31 is 3.36mm. This solution increases the rock-breaking effect of the co-track cutting tooth 321 by increasing the co-track deviation Pv, reduces the cutting effect of the main cutting tooth 311, and reduces the specific pressure on the main cutting tooth 311, thereby making the drill bit slightly less aggressive, but relatively more stable and more wear-resistant. Embodiments 2 and 3 are two opposite co-track deviations, and the unbalanced force generated on the blade is also opposite. By adjusting the co-track deviation, the unbalanced force of the drill bit can be reduced and the stability of the drill bit can be enhanced.

Embodiment 4: The difference between this solution and embodiment 1 is that the radial tooth arrangement starting position Inp of the same-track cutting blade 32 is at 64.77 mm. In this solution, the same-track cutting blade 32 is shorter, and the aggressiveness is enhanced on the basis of unchanged stability.

Embodiment 5: The difference between this solution and embodiment 1 is that the radial tooth arrangement envelope 314 of the main cutting blade and the radial tooth arrangement envelope 324 of the co-track cutting blade are offset by a distance d equal to -1.344 mm. In this solution, the co-track cutting teeth 321 on the co-track cutting blade 32 first eat into the rock, causing pre-crushing of the bottom of the well, and the drill bit is the most aggressive.

Embodiment 6: The difference between this solution and Embodiment 1 and Embodiment 3 is that the radial tooth arrangement envelope 314 of the main cutting blade and the radial tooth arrangement envelope 324 of the same track cutting blade are offset by a distance d of 1.344 mm. In this solution, the main cutting teeth 311 only touch the rock after the same track cutting teeth 321 have penetrated the rock to a depth of 1.344 mm, and the specific pressure is mainly borne by the main cutting teeth 311. At this time, the drill bit is more aggressive.

Embodiment 7: As shown in FIG4, this is an implementation scheme of a high pressure ratio PDC drill bit, the radius R of the drill bit is 107.95 mm, the radius r of the main cutting tooth 311 is 6.72 mm, and single-row flat round teeth are arranged on the main cutting blade 31 and the co-track cutting blade 32. Three groups of high pressure ratio blade groups 3 are distributed circumferentially on the top of the drill bit, and each group of high pressure ratio blade groups 3 consists of a main cutting blade 31 and a co-track cutting blade 32. The difference from Embodiment 1 is that the co-track cutting blade 32 is arranged in the counterclockwise direction along the circumference of the main cutting blade 31. The radial position of the co-track cutting tooth 321 installed on the co-track cutting blade 32 is 0 with respect to the co-track deviation of the main cutting tooth 311 installed on the main cutting blade 31 of the same group. The radial tooth layout envelope 314 of the main cutting blade coincides with the radial tooth layout envelope 324 of the co-track cutting blade. The radial tooth arrangement starting position Inp of the same-track cutting blade 32 is at 32.385 mm. The same-track cutting blade 32 is in front of the main cutting blade 31 in the direction of travel, and the rock in the same-track offset zone 323 first contacts the cutting teeth on the same-track cutting blade 32, thereby reducing the impact of the rock on the main cutting blade 31, indirectly enhancing the impact resistance of the main cutting teeth 311, but also reducing the aggressiveness of the drill bit to a certain extent.

Embodiment 8: A high pressure ratio PDC drill bit as shown in FIG5, the radius R of the drill bit is 107.95 mm, the radius r of the main cutting tooth 311 is 6.72 mm, and single-row flat round teeth are arranged on both the main cutting blade 31 and the co-track cutting blade 32. The difference from Embodiment 1 is that two groups of high pressure ratio blade groups 3 are distributed circumferentially on the top of the drill bit, and each group of high pressure ratio blade groups 3 is composed of a main cutting blade 31 and two co-track cutting blades 32. The two co-track cutting blades 32 are arranged in the clockwise direction along the circumference of the main cutting blade 31. The radial position deviation (co-track deviation Pv) between the co-track cutting teeth 321 installed on the co-track cutting blade 32 and the radial position deviation (co-track deviation Pv) of the main cutting teeth 311 installed on the main cutting blade 31 of the same group is 0. The radial tooth layout envelope 314 of the main cutting blade coincides with the radial tooth layout envelope 324 of the co-track cutting blade. The radial tooth arrangement starting position Inp of the same track cutting blade 32 is at 32.385 mm. The beneficial effect of this solution is that the polygon effect of the drill bit is lower, the stability is stronger, and the aggressiveness is stronger.

Embodiment 9: A high pressure ratio PDC drill bit as shown in FIG6, the radius R of the drill bit is 107.95 mm, the radius r of the main cutting tooth 311 is 6.72 mm, and single-row flat round teeth are arranged on both the main cutting blade 31 and the co-track cutting blade 32. The difference from Embodiment 1 is that two groups of high pressure ratio blade groups 3 are distributed circumferentially on the top of the drill bit, and each group of high pressure ratio blade groups 3 is composed of a main cutting blade 31 and two co-track cutting blades 32. The difference from Embodiment 8 is that the two co-track cutting blades 32 are arranged in the counterclockwise direction along the circumference of the main cutting blade 31. The radial position deviation (co-track deviation Pv) between the co-track cutting teeth 321 installed on the co-track cutting blade 32 and the radial position deviation (co-track deviation Pv) of the main cutting teeth 311 installed on the main cutting blade 31 of the same group is 0. The radial tooth layout envelope 314 of the main cutting blade coincides with the radial tooth layout envelope 324 of the co-track cutting blade. The radial tooth arrangement starting position Inp of the same track cutting blade 32 is at 32.385 mm. The beneficial effect of this solution is that the polygon effect of the drill bit is lower, the stability is stronger, the aggressiveness is weakened, and the impact resistance is enhanced.

Embodiment 10: A high pressure ratio PDC drill bit as shown in FIG7, the radius R of the drill bit is 107.95 mm, the radius r of the main cutting tooth 311 is 6.72 mm, and single-row flat round teeth are arranged on both the main cutting blade 31 and the co-track cutting blade 32. The difference from Embodiment 1 is that two groups of high pressure ratio blade groups 3 are distributed circumferentially on the top of the drill bit, and each group of high pressure ratio blade groups 3 is composed of a main cutting blade 31 and two co-track cutting blades 32. The difference from Embodiment 8 and Embodiment 9 is that the two co-track cutting blades 32 are arranged with the main cutting blade 31 in between, and the co-track cutting blade 32 arranged along the clockwise direction of the circumference of the main cutting blade 31 mainly plays a role in enhancing stability and wear resistance, and the co-track cutting blade 32 arranged along the counterclockwise direction of the circumference of the main cutting blade 31 mainly plays a role in enhancing stability and impact resistance. The radial position deviation (co-track deviation Pv) between the co-track cutting teeth 321 installed on the co-track cutting blade 32 and the main cutting teeth 311 installed on the main cutting blade 31 of the same group is 0. The radial tooth arrangement envelope 314 of the main cutting blade coincides with the radial tooth arrangement envelope 324 of the co-track cutting blade. The radial tooth arrangement starting position Inp of the co-track cutting blade 32 is at 32.385 mm. The beneficial effect of this solution is that the polygon effect of the drill bit is lower, and at the same time, the stability and impact resistance of the drill bit are enhanced.

Embodiment 11: The difference between this solution and Embodiment 8, Embodiment 9 and Embodiment 10 is that the two high pressure blade groups 3 distributed at the top of this solution are respectively a double blade group and a triple blade group, the main cutting blade 31 of the double blade group is provided with a same track cutting blade 32 along the clockwise direction of the circumference, and the main cutting blade 31 of the triple blade group is provided with a same track cutting blade 32 along the clockwise and counterclockwise directions of the circumference. The beneficial effect of this solution is that the aggressiveness of the high pressure blade group 3 is selectively improved by adjusting the number of blades in the group. For example, compared with Embodiment 8, Embodiment 9 and Embodiment 10, in the high pressure blade group 3 with a small number of blades, the drilling pressure on a single blade is further increased, that is, the pressure ratio is further improved, thereby enhancing the aggressiveness of the drill bit.

Embodiment 12: A high pressure ratio PDC drill bit as shown in FIG8 , the radius R of the drill bit is 107.95 mm, and the radius r of the main cutting tooth 311 is 6.72 mm. Three groups of high pressure ratio blade groups 3 are distributed circumferentially on the top of the drill bit, and each group of high pressure ratio blade groups 3 consists of a main cutting blade 31 and a co-track cutting blade 32. The co-track cutting blade 32 is arranged in the clockwise direction along the circumference of the main cutting blade 31. Planar round teeth are arranged on the co-track cutting blade 32, which are co-track cutting teeth 321. The difference from Embodiment 1 is that double rows of planar round teeth are arranged on the main cutting blade 31, namely the main cutting teeth 311 and the first backup teeth 316. The radial position deviation (co-track deviation Pv) between the co-track cutting teeth 321 installed on the co-track cutting blade 32 and the main cutting teeth 311 installed on the main cutting blade 31 of the same group is 0. The radial tooth arrangement envelope 314 of the main cutting blade coincides with the radial tooth arrangement envelope 324 of the co-track cutting blade. The radial tooth arrangement starting position Inp of the co-track cutting blade 32 is at 32.385 mm. The beneficial effect of this solution is that the main cutting blade 31 is arranged with two rows of cutting teeth, the main cutting teeth 311 of the first row are mainly used for cutting rocks, and the first backup teeth 316 of the second row are mainly used to enhance the wear resistance of the drill bit, improve the stress condition of the main cutting teeth 311, and thus enhance the service life of the main cutting teeth 311.

Embodiment 13: A high pressure ratio PDC drill bit as shown in FIG9, the radius R of the drill bit is 107.95 mm, and the radius r of the main cutting tooth 311 is 6.72 mm. Three groups of high pressure ratio blade groups 3 are distributed circumferentially on the top of the drill bit, and each group of high pressure ratio blade groups 3 consists of a main cutting blade 31 and a co-track cutting blade 32. The co-track cutting blade 32 is arranged in the clockwise direction along the circumference of the main cutting blade 31. Planar circular teeth, namely, main cutting teeth 311, are arranged on the main cutting blade 31. The difference from Embodiment 1 is that double rows of cutting teeth, namely, co-track cutting teeth 321 and second backup teeth 326, are arranged on the co-track cutting blade 32. The radial position deviation (co-track deviation Pv) between the co-track cutting teeth 321 installed on the co-track cutting blade 32 and the radial position deviation of the main cutting teeth 311 installed on the main cutting blade 31 of the same group is 0. The radial tooth arrangement envelope 314 of the main cutting blade coincides with the radial tooth arrangement envelope 324 of the same-track cutting blade. The radial tooth arrangement starting position Inp of the same-track cutting blade 32 is at 32.385 mm. The beneficial effect of this solution is that the same-track cutting blade 32 is arranged with double rows of flat round teeth, which increases the contact points of the same-track cutting blade 32. On the one hand, it plays a role in limiting the depth of the main cutting blade 31, so that the load fluctuation of the main cutting teeth 311 on the main cutting blade 31 is smaller; on the other hand, it increases the stability of the drill bit and prolongs the life of the drill bit.

According to the characteristics of the formation and working conditions, the cutting teeth of the high specific pressure PDC drill bit of the present invention can be arranged with non-planar teeth.

Embodiment 14: A high pressure ratio PDC drill bit as shown in FIG10, the radius R of the drill bit is 107.95 mm, and the radius r of the main cutting tooth 311 is 6.72 mm. The difference from embodiment 1 is that the main cutting teeth 311 of the main cutting blade 31 of this scheme are arranged as a single row of wide blade teeth. Three groups of high pressure ratio blade groups 3 are distributed circumferentially on the top of the drill bit, and each group of high pressure ratio blade groups 3 consists of a main cutting blade 31 and a co-track cutting blade 32. The co-track cutting blade 32 is arranged in the clockwise direction along the circumference of the main cutting blade 31. The radial position deviation (co-track deviation Pv) of the co-track cutting teeth 321 installed on the co-track cutting blade 32 and the radial position deviation of the main cutting teeth 311 installed on the main cutting blade 31 of the same group is 0. The radial tooth layout envelope 314 of the main cutting blade coincides with the radial tooth layout envelope 324 of the co-track cutting blade. The radial tooth arrangement starting position Inp of the same track cutting blade 32 is at 32.385mm. The beneficial effect of this solution is to use the high specific pressure tooth edge of the wide blade tooth to enhance the aggressiveness of the drill bit; in addition, the flat edge of the wide blade tooth makes the cutting tooth and the rock in line contact, and the contact line is a straight line, which basically coincides with the crown curve. In the same radial range of the crown, a small number of wide blade teeth can achieve full coverage of the bottom of the well, further improving the specific pressure on a single tooth.

Embodiment 15: A high pressure ratio PDC drill bit as shown in FIG11, the radius R of the drill bit is 107.95 mm, and the radius r of the main cutting tooth 311 is 6.72 mm. The difference from embodiment 1 is that the main cutting teeth 311 of the main cutting blade 31 of this scheme are arranged as a single row of ridge teeth. Three groups of high pressure ratio blade groups 3 are distributed circumferentially on the top of the drill bit, and each group of high pressure ratio blade groups 3 consists of a main cutting blade 31 and a co-track cutting blade 32. The co-track cutting blade 32 is arranged in the clockwise direction along the circumference of the main cutting blade 31. The radial position deviation (co-track deviation Pv) of the co-track cutting teeth 321 installed on the co-track cutting blade 32 and the radial position deviation of the main cutting teeth 311 installed on the main cutting blade 31 of the same group is 0. The radial tooth layout envelope 314 of the main cutting blade coincides with the radial tooth layout envelope 324 of the co-track cutting blade. The radial tooth arrangement starting position Inp of the same track cutting blade 32 is at 32.385 mm. The beneficial effect of this solution is that the contact between the ridge-shaped tooth working surface and the rock is a continuous process, thereby improving the impact resistance of the drill bit.

Embodiment 16: A high pressure ratio PDC drill bit as shown in FIG12, the radius R of the drill bit is 107.95 mm, and the radius r of the main cutting tooth 311 is 6.72 mm. The difference from the embodiment 1 is that the co-track cutting teeth 321 of the co-track cutting blade 32 of this scheme are arranged as a single row of ridge-shaped teeth. Three groups of high pressure ratio blade groups 3 are distributed circumferentially on the top of the drill bit, and each group of high pressure ratio blade groups 3 consists of a main cutting blade 31 and a co-track cutting blade 32. The co-track cutting blade 32 is arranged in the clockwise direction along the circumference of the main cutting blade 31. The radial position deviation (co-track deviation Pv) of the co-track cutting teeth 321 installed on the co-track cutting blade 32 and the radial position deviation of the main cutting teeth 311 installed on the main cutting blade 31 of the same group is 0. The radial tooth layout envelope 314 of the main cutting blade coincides with the radial tooth layout envelope 324 of the co-track cutting blade. The radial tooth arrangement starting position Inp of the same track cutting blade 32 is at 32.385 mm. The beneficial effect of this solution is that the contact between the ridge-shaped tooth working surface and the rock is a continuous process, thereby improving the impact resistance of the same track cutting blade 32 and enhancing the stability of the drill bit.

Comparative Example 1: The difference between this solution and Example 1 is that the radial position of the co-track cutting teeth 321 installed on the co-track cutting blade 32 and the co-track deviation Pv of the main cutting teeth 311 on the same group of main cutting blade 31 is -4.12mm. In this solution, the co-track cutting teeth 321 share more specific pressure, resulting in a smaller specific pressure of the main cutting blade 31, which makes the aggressiveness of the drill bit significantly lower.

Comparative Example 2: The difference between this solution and Example 1 is that the radial position of the co-track cutting teeth 321 installed on the co-track cutting blade 32 and the co-track deviation Pv of the main cutting teeth 311 on the same group of main cutting blade 31 is 4.06 mm. In this solution, the co-track cutting teeth 321 share more specific pressure, resulting in a smaller specific pressure of the main cutting blade 31, which makes the aggressiveness of the drill bit significantly lower.

Comparative Example 3: The difference between this solution and Example 4 is that the radial tooth arrangement starting position Inp of the same track cutting blade 32 is at 20.52. In this solution, the same track cutting blade 32 is too long, which makes its aggressiveness biased and is not conducive to the discharge of rock chips.

Comparative Example 4: The difference between this solution and Example 4 is that the radial tooth arrangement starting position Inp of the same track cutting blade 32 is at 90.22. In this solution, the same track cutting blade 32 is very short, which makes its stability deviation.

Comparative Example 5: The difference between this solution and Example 5 is that the offset distance d between the radial tooth arrangement envelope 314 of the main cutting blade and the radial tooth arrangement envelope 324 of the co-track cutting blade is equal to -2.016 mm. In this solution, the co-track cutting teeth 321 on the co-track cutting blade 32 first eat into the rock, but the offset distance d is too large, causing the co-track cutting teeth 321 to be easily worn, which affects their service life.

Comparative Example 6: The difference between this solution and Example 6 is that the offset distance d between the radial tooth arrangement envelope 314 of the main cutting blade and the radial tooth arrangement envelope 324 of the same track cutting blade is equal to 2.016 mm. In this solution, the main cutting teeth 311 first bite into the rock, but the offset distance d is too large, which makes the main cutting teeth 311 very easy to be worn, affecting its service life.

The drill bits obtained in Examples 1 to 16 and Comparative Examples 1 to 6 were subjected to drilling tests, and the test results of Examples 1 to 3 and Comparative Examples 1 and 2 were recorded, and Table 1 was obtained;

The test results of Example 4, Comparative Examples 3 and 4 are recorded to obtain Table 2;

The test results of Examples 5 and 6 and Comparative Examples 5 and 6 are recorded to obtain Table 3;

By recording the test results of Examples 7 to 11, Table 4 can be obtained; by recording the test results of Examples 12 to 16, Table 5 can be obtained, in which the performance is ranked as follows: poor < poor < general < slightly stronger < stronger < strong.

Table 1 Characteristics, dimensions and test results of Examples 1 to 3 of the present invention and Comparative Examples 1 and 2

It can be seen from Examples 1 to 3, Comparative Examples 1 and 2, and the experimental evaluation in Table 1 that the scheme sets the on-track deviation value Pv range of the on-track cutting tooth 321 installed on the on-track cutting wing 32 and the corresponding main cutting tooth 311 installed on the main cutting wing 31 of the same group within -0.5r to 0.5r, and appropriately limits the auxiliary cutting function of the on-track cutting tooth 321, so that the overall aggressiveness and stability of the drill bit, as well as the impact resistance and wear resistance are relatively excellent. Within this deviation range, a reasonable deviation distance can be adjusted to meet the engineering needs of different formations.

Table 2 Characteristics, dimensions and test results of Example 4 of the present invention and Comparative Examples 3 and 4

From the fourth embodiment, the third and fourth comparative examples, and the test evaluation in Table 2, it can be seen that the scheme arranges the cutting teeth on the same track cutting blade 32 in the radial peripheral part of the drill bit by setting the radial tooth arrangement starting position of the same track cutting blade 32 within the range of 0.25R-0.8R, so that the same track cutting blade 32 can bear more wear, enhance the wear resistance of the drill bit, extend the service life, increase the contact points on the radial periphery of the drill bit, effectively reduce the polygon effect during drilling, increase the stability of the drill bit, and have strong aggressiveness. The length of the same track cutting blade 32 can be adjusted according to the different formation lithology and working conditions to balance the aggressiveness and wear resistance of the drill bit.

Table 3 Characteristics, dimensions and test results of Examples 5 to 6 of the present invention and Comparative Examples 5 to 6

It can be seen from Examples 5 and 6, Comparative Examples 5 and 6, combined with the experimental evaluation in Table 3, that the scheme can ensure the aggressiveness and stability of the drill bit at the same time by aligning the radial tooth arrangement envelope 314 of the main cutting blade and the radial tooth arrangement envelope 324 of the same-track cutting blade or setting the offset distance d within the range of -0.2r≤d≤0.2r, and within this distance range, appropriate adjustments can be made to adapt to the engineering needs of different formations.

Table 4 Characteristics, dimensions and test results of embodiments 7 to 11 of the present invention

Table 5 Characteristics, dimensions and test results of embodiments 12 to 16 of the present invention

From Examples 7 to 16, combined with the test evaluation in Tables 4 and 5, it can be seen that when the on-track deviation value Pv, the radial tooth layout starting position of the on-track cutting blade 32, and the offset distance d are all set within an appropriate range, the on-track cutting blade 32 is set in the clockwise or counterclockwise direction along the circumference of the main cutting blade 31, or the number and orientation of the high-pressure blade group 3, as well as the cutting tooth shape on the blade can be adaptively adjusted according to the different lithology and working conditions, while ensuring that the drill bit has better aggressiveness and stability.

It is worth noting that in some of the above embodiments, in the high pressure blade group 3 on the same drill bit, the blade structures in the group are the same. This is because the embodiments introduce representative features. If the blade structures in different high pressure blade groups 3 are slightly adjusted to result in different blade structures in different groups, even if the use effect is not as good as the beneficial effects of the above representative embodiments, it still falls within the scope of protection of the present invention. For example, the blade structures in the high pressure blade group 3 of the embodiment 12 (arranged clockwise) are changed to two groups of "main cutting blade 31 + same track cutting blade 32" and one group of "same track cutting blade 32 + main cutting blade 31". In this way, even if the beneficial effects of the adjusted scheme are not as obvious as those of the embodiment 12, it still falls within the scope of protection of the present invention.

The technical features of the above-described embodiments may be arbitrarily combined. To make the description concise, not all possible combinations of the technical features in the above-described embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

The above-mentioned embodiments only express several implementation methods of the present invention, and the descriptions thereof are relatively specific and detailed, but they cannot be understood as limiting the scope of the invention patent. It should be pointed out that, for ordinary technicians in this field, several variations and improvements can be made without departing from the concept of the present invention, and these all belong to the protection scope of the present invention. Therefore, the protection scope of the patent of the present invention shall be subject to the attached claims.

Claims (9)

1. A high specific pressure PDC drill bit, comprising a joint and a drill bit body, wherein the joint is fixedly connected to one end of the drill bit body, and characterized in that: at least two groups of high specific pressure blade groups are distributed along the circumferential direction at the other end of the drill bit body, wherein the high specific pressure blade groups include a main cutting blade and at least one co-track cutting blade, and the radial position deviation Pv of the co-track cutting teeth installed on the co-track cutting blade and the radial position deviation Pv of the main cutting teeth installed on the main cutting blade of the same group is in the range of -0.5r to 0.5r, wherein r is the radius of the main cutting teeth; The number of main cutting teeth installed on the main cutting blade meets and Where N represents the number of main cutting blades, _ni is the number of main cutting teeth on the i-th main cutting blade, r is the radius of the main cutting teeth, and R is the radius of the drill bit. 2. A high specific pressure PDC drill bit according to claim 1, characterized in that: in the high specific pressure blade group, the same track cutting blade is arranged in the clockwise or counterclockwise direction along the circumference of the main cutting blade. 3. A high specific pressure PDC drill bit according to claim 1, characterized in that: the tooth arrangement envelopes of the main cutting blade and the same track cutting blade coincide or are offset, and the offset distance d satisfies: -0.2r≤d≤0.2r. 4. A high specific pressure PDC drill bit according to claim 1, characterized in that the cutting teeth on the same track cutting blade are arranged on the radial peripheral part of the drill bit. 5. A high specific pressure PDC drill bit according to claim 4, characterized in that the radial tooth arrangement starting position of the same track cutting blade is within the range of 0.25R-0.8R, where R is the radius of the drill bit. 6. A high specific pressure PDC drill bit according to claim 1, characterized in that the main cutting teeth on the main cutting blades are wide-edge teeth. 7. A high specific pressure PDC drill bit according to claim 1, characterized in that the on-track cutting teeth on the on-track cutting blades are non-planar teeth. 8. A high specific pressure PDC drill bit according to claim 1, characterized in that: the main cutting blade is arranged with double or multiple rows of cutting teeth, and/or the same track cutting blade is arranged with double or multiple rows of cutting teeth. 9. A high specific pressure PDC drill bit according to claim 1, characterized in that the number of blades in different high specific pressure blade groups on the same drill bit is different.