Self-adapting elastic tooth unit drill bit for soft and hard interbedded strata

Abstract

The application discloses a soft-hard interbedded stratum adaptive elastic tooth unit drill bit, relates to a drill bit and a drilling tool for rock and soil in the field of engineering construction, and belongs to the drilling and well drilling field. The drill bit comprises a drill bit base body, a plurality of fixed drill bit tooth units, a plurality of adaptive elastic tooth units and drill bit gages. The fixed drill bit tooth units are fixedly arranged on the upper end of the drill bit base body. The plurality of adaptive elastic drill bit tooth units are uniformly distributed on the upper end of the drill bit base body through adaptive elastic elements. The fixed drill bit tooth units are distributed between two adjacent adaptive elastic drill bit tooth units. A plurality of groups of drill bit gages are uniformly distributed on the inner and outer sides of the adaptive elastic drill bit tooth units and the fixed drill bit tooth units. The height difference of the adaptive elastic drill bit tooth units and the fixed drill bit tooth units is changed to realize the switching of the back rake angle or the lip structure of the drill bit, so that efficient drilling in different strata is realized, and the cutting depth is adaptive.

Description

TECHNICAL FIELD

[0001] The present application relates to a drilling tool for soft and hard alternating strata, in particular to a self-adaptive elastic tooth unit drill bit. BACKGROUND

[0002] At present, whether it is oil and gas drilling, geological drilling or engineering drilling, drilling is still the main way to explore the structure of underground rock layers. As the pioneer of downhole drilling, the drill bit directly affects the drilling efficiency. Especially in deep hole drilling, each cycle costs a lot, so the quality of the drill bit will have a greater impact on the cost.

[0003] Underground rock layers are non-homogeneous bodies with cracks, anisotropy and soft and hard alternation. The characteristics of such rock properties make it difficult to study the drill bit. Moreover, as the resources in the shallow part are increasingly exhausted, the exploration and development of deep resources are accelerating. However, as the drilling depth increases, the geological environment of deep strata becomes more and more complex, and the heterogeneity of the strata is more and more obvious. For a long time, researchers have studied corresponding high-performance drill bits for rocks with different physical and mechanical properties, and good results have been achieved. However, these drill bits have poor adaptability to changes in rock properties. In actual drilling, a drill hole often encounters strata with large differences in rock properties. Therefore, it is difficult to develop a drill bit with strong adaptability to strata.

[0004] PDC drill bits are mainly used for drilling soft to medium-hard strata and are widely used. However, when the drill bit drills into hard strata, soft and hard alternating layers, high abrasion strata, gravel layers, broken rock layers, etc., the mechanical speed of the PDC drill bit will suddenly decrease, causing the PDC cutting teeth to wear out faster and the polycrystalline diamond layer to fracture and even fall off, thereby reducing the drilling efficiency of the PDC drill bit. In addition, the back rake angle of the PDC drill bit cutting teeth has a great influence on the mechanical drilling speed and drill bit life. When cutting soft rock, a smaller back rake angle will have a faster mechanical drilling speed; when drilling hard rock, the back rake angle needs to be appropriately increased, which is beneficial to reducing the damage of the impact of hard rock to the polycrystalline diamond compact.

[0005] Impregnated diamond drill bits are often used in hard rock strata and mainly use grinding to break rock. The lip structure of the impregnated diamond drill bit will affect the drilling pressure on each diamond and the exposure of the diamond, thereby affecting the mechanical drilling speed of the impregnated diamond drill bit.

[0006] In the field of oil drilling bits, some scholars have studied the adaptability of the drill bit. For example, the invention patent "PDC drill bit with swing self-adaptive buffer structure" (Patent No. 202011127823.2) uses the swing of the buffer structure to absorb impact load when drilling in soft and hard interbedded strata or heterogeneous strata and under complex motion conditions such as composite drilling, thereby avoiding damage to the cutting teeth. Further, after the impact, the buffer structure can swing to a predetermined low position, thereby reducing the impact on the cutting tooth penetration depth to protect the rock breaking efficiency of the drill bit. However, the drill bit buffer structure is relatively complex and has poor stability. For example, in the field of coring drill bits. The invention patents "Bionic self-adaptive PDC drill bit" (Patent No. 201510428061.2) and "PDC-impregnated block hybrid self-adaptive drill bit" (Patent No. 201610429601.3) of Jilin University disclose a PDC drill bit that can change the back rake angle according to the stratum. However, the invention is difficult to prepare and has poor quality stability, making it difficult to promote and apply. Moreover, during drilling in heterogeneous rock formations, the change in the self-adaptive angle can cause the lower part of the self-adaptive tooth to deviate from the tooth distribution track, causing the inner and outer diameters of the drill bit to change, thereby affecting the drilling quality and reducing the service life of the polycrystalline diamond compact. Therefore, it is of great significance to invent a bionic self-adaptive drill bit that can overcome the above technical problems. SUMMARY

[0007] The purpose of the present application is to address the poor adaptability of the drill bit to the stratum, solve the problems of low drilling efficiency of the drill bit, easy damage of the drill bit teeth, and deviation of the lower part of the self-adaptive tooth from the tooth distribution track after the change in the self-adaptive angle, which affects the drilling quality, and provide a soft and hard interbedded stratum self-adaptive elastic tooth unit drill bit.

[0008] A soft and hard interbedded stratum self-adaptive elastic tooth unit drill bit, comprising a drill bit base, a plurality of fixed drill bit tooth units, a plurality of self-adaptive elastic drill bit tooth units, and a plurality of groups of drill bit stabilizers.

[0009] The plurality of self-adaptive elastic drill bit tooth units are uniformly distributed on the upper end of the drill bit base by self-adaptive elastic elements, the fixed drill bit tooth units are spaced apart between the adjacent two self-adaptive elastic drill bit tooth units, and the plurality of groups of drill bit stabilizers are uniformly distributed on the inner and outer sides of the self-adaptive elastic drill bit tooth units and the fixed drill bit tooth units.

[0010] The adaptive elastic element comprises an adaptive elastic element joint, an adaptive elastic element buckle and an adaptive elastic element disc spring, the adaptive elastic element buckle is fixedly connected with the drill bit body, the adaptive elastic element joint is buckled to the drill bit body through the adaptive elastic element buckle, the adaptive elastic element joint can slide up and down outside the protrusion of the drill bit body, the adaptive elastic element disc spring is fixedly connected with the drill bit body at the lowermost position, and the adaptive elastic element disc spring is fixedly connected with the adaptive elastic element joint at the uppermost position.

[0011] Preferably, the adaptive elastic element disc spring is fixedly connected by a plurality of disc springs in positive and negative alternation.

[0012] Preferably, a flexible filling is filled between the adaptive elastic element joint and the drill bit body, the height of the flexible filling is less than or equal to the maximum height of the adaptive elastic element disc spring, and the flexible filling material is an elastic material of rubber.

[0013] Preferably, the back rake angle of the adaptive elastic drill bit tooth unit is β0, and the back rake angle of the fixed drill bit tooth unit is β1, wherein β0 is set to be between 0° and 15°, β1 is set to be between 15° and 25°, and β0 < β1.

[0014] Preferably, the difference between the bottom end surface of the adaptive elastic drill bit tooth unit and the bottom end surface of the fixed drill bit tooth unit is h when the drill bit is not working.

[0015] Preferably, the fixed drill bit tooth unit is a fixed PDC drill bit cutting tooth, and the adaptive elastic drill bit tooth unit is an adaptive elastic PDC drill bit cutting tooth.

[0016] When drilling in a relatively soft formation, only the adaptive elastic PDC drill bit cutting tooth works to cut the relatively soft rock, when drilling in a relatively hard formation, the drilling pressure is increased to make the adaptive elastic element disc spring contract, so that the adaptive elastic PDC drill bit cutting tooth as a whole descends until it is flush with the fixed PDC drill bit cutting tooth, at this time, the fixed PDC drill bit cutting tooth participates in drilling to play a major role in rock breaking, and the adaptive elastic PDC drill bit cutting tooth assists in drilling, when drilling in a relatively soft formation again, the drilling pressure is reduced to release the elastic force of the adaptive elastic element disc spring, so that the adaptive elastic PDC drill bit cutting tooth rises again to play a major role in rock breaking.

[0017] Preferably, the fixed drill bit tooth unit is a fixed impregnated diamond drill bit tooth, and the adaptive elastic drill bit tooth unit is an adaptive elastic impregnated diamond drill bit tooth.

[0018] The self-adaptive elastic impregnated diamond bit tooth plays a main role in breaking rock when drilling in soft rock; when drilling in hard rock, the self-adaptive elastic impregnated diamond bit tooth is reduced in height by increasing the drilling pressure, the fixed impregnated diamond bit tooth is exposed to play a main role in breaking rock, and the self-adaptive elastic impregnated diamond bit tooth plays an auxiliary role in breaking rock; the fixed impregnated diamond bit tooth has N ring teeth, the self-adaptive elastic impregnated diamond bit tooth has M ring teeth, and N >= M.

[0019] Preferably, the fixed bit tooth unit is a fixed impregnated diamond bit tooth, and the self-adaptive elastic bit tooth unit is a self-adaptive elastic PDC bit cutting tooth; when drilling in soft rock stratum, the self-adaptive elastic PDC bit cutting tooth breaks rock in a cutting manner; when drilling in hard rock stratum, the self-adaptive elastic PDC bit cutting tooth is contracted by increasing the drilling pressure, and the fixed impregnated diamond bit tooth is exposed to break hard rock in a grinding manner.

[0020] Preferably, the fixed bit tooth unit and the self-adaptive elastic bit tooth unit are all made of polycrystalline diamond compact, Si-Mn alloy series spring steel or hard alloy.

[0021] Preferably, the self-adaptive elastic element joint and the self-adaptive elastic element buckle are made of spring steel material.

[0022] Compared with the prior art, the present application has the following beneficial effects:

[0023] The self-adaptive elastic bit tooth unit can automatically adjust the cutting depth or grinding depth under the action of the drilling pressure through the self-adaptive elastic element according to the different drilling pressure and hole bottom conditions; when drilling in soft rock stratum, the self-adaptive elastic bit tooth unit drills in the hole by using the elastic force of the disc spring as support; when drilling in hard rock stratum, the self-adaptive elastic element is continuously compressed with the increase of the drilling pressure, the fixed bit tooth unit is exposed, and plays a main role in breaking rock; then, the back rake angle or the lip structure of the bit is switched by changing the height difference between the self-adaptive elastic bit tooth unit and the fixed bit tooth unit, so that efficient drilling in different strata is realized.

[0024] The existence of the disc spring of the self-adaptive elastic element can provide a buffer for the self-adaptive elastic bit tooth unit to adaptively adjust the cutting depth according to the hardness of the rock during drilling, so that the effect of shock absorption is achieved, the impact damage of the polycrystalline diamond compact is reduced, and the service life of the bit is improved.

[0025] The movement trajectory of the self-adaptive elastic bit tooth unit is in the vertical direction, so the self-adaptive process of the bit tooth unit does not change the lower part of the self-adaptive tooth from the tooth arrangement track after the self-adaptive angle is changed, so that the inner and outer diameters of the bit do not change, the quality of the drilling hole is ensured, the lateral wear of the polycrystalline diamond compact is reduced, and the service life of the polycrystalline diamond compact is increased.

[0026] The height of h can be controlled by adjusting the spring parameters and the number of springs of the adaptive elastic element, and the drilling pressure that causes the adaptive change of the adaptive elastic bit tooth unit can be controlled. Therefore, the present application has simple structure, is easy to install and control. BRIEF DESCRIPTION OF DRAWINGS

[0027] The accompanying drawings, which are included to provide a further understanding of the application and are incorporated in and constitute a part of this application, illustrate embodiment(s) of the application and together with the description serve to explain the application. In the drawings:

[0028] Figure 1 is a perspective view of an adaptive elastic PDC cutting tooth drill bit according to the present application.

[0029] Figure 2 is a cross-sectional view of an adaptive elastic element according to the present application.

[0030] Figure 3 is a view showing the cooperation of a buckle and a buckle joint of an adaptive elastic element according to the present application.

[0031] Figure 4 is a view showing the cooperation of a disc spring and a drill bit body of an adaptive elastic element according to the present application.

[0032] Figure 5 is a view showing the cooperation of a buckle joint and a disc spring of an adaptive elastic element according to the present application.

[0033] Figure 6 is a top view of an adaptive elastic PDC cutting tooth drill bit according to the present application.

[0034] Figure 7 is a perspective view of an adaptive PDC cutting tooth according to the present application.

[0035] Figure 8 is a perspective view of a fixed PDC cutting tooth according to the present application.

[0036] Figure 9 is a view showing the state of a cutting tooth of an adaptive elastic PDC cutting tooth drill bit according to the present application when cutting soft rock.

[0037] Figure 10 is a view showing the state of a cutting tooth of an adaptive elastic PDC cutting tooth drill bit according to the present application when cutting hard rock.

[0038] Figure 11 is a cross-sectional view of an adaptive elastic element of an adaptive elastic PDC cutting tooth drill bit according to the present application when cutting hard rock.

[0039] Figure 12is a three-dimensional schematic view of a self-adapting elastic PDC cutting tooth and impregnated diamond fixed tooth unit hybrid drill bit according to the present application.

[0040] Figure 13 is a top view of a self-adapting elastic PDC cutting tooth and impregnated diamond fixed tooth unit hybrid drill bit according to the present application.

[0041] Figure 14 is a schematic view of the state of the cutting tooth when the self-adapting elastic PDC cutting tooth and impregnated diamond fixed tooth unit hybrid drill bit grinds soft rock according to the present application.

[0042] Figure 15 is a schematic view of the state of the cutting tooth when the self-adapting elastic PDC cutting tooth and impregnated diamond fixed tooth unit hybrid drill bit grinds hard rock according to the present application.

[0043] Figure 16 is a three-dimensional schematic view of a self-adapting elastic PDC cutting tooth and impregnated diamond fixed tooth unit hybrid drill bit according to the present application.

[0044] Figure 17 is a top view of a self-adapting elastic PDC cutting tooth and impregnated diamond fixed tooth unit hybrid drill bit according to the present application.

[0045] Figure 18 is a schematic view of the state of the cutting tooth when the self-adapting elastic PDC cutting tooth and impregnated diamond fixed tooth unit hybrid drill bit grinds soft rock according to the present application.

[0046] Figure 19 is a schematic view of the state of the cutting tooth when the self-adapting elastic PDC cutting tooth and impregnated diamond fixed tooth unit hybrid drill bit grinds and grinds hard rock according to the present application.

[0047] The various marks in the drawings are as follows: 1 - drill bit base, 2 - fixed drill bit tooth unit, 21 - fixed PDC drill bit cutting tooth, 22 - fixed impregnated diamond drill bit tooth, 3 - self-adapting elastic drill bit tooth unit, 31 - self-adapting elastic element, 3101 - self-adapting elastic element joint, 3102 - self-adapting elastic element buckle, 3103 - self-adapting elastic element disc spring, 32 - self-adapting elastic PDC drill bit cutting tooth, 33 - self-adapting elastic impregnated diamond drill bit tooth, 4 - drill bit gauge. DETAILED DESCRIPTION

[0048] In order to more clearly illustrate the present application, a further description will be made in connection with the specific implementation methods. Those skilled in the art should understand that the specific description below is illustrative rather than limiting, and should not limit the scope of protection of the present application. Unless otherwise defined, the technical terms or scientific terms used herein should be understood as the usual meaning understood by those skilled in the art in the field to which the present application belongs.

[0049] Embodiment one: fixed bit tooth unit 2 selects fixed PDC bit cutting tooth 21; adaptive elastic bit tooth unit 3 is adaptive elastic PDC bit cutting tooth 32.

[0050] A soft and hard interbedded formation adaptive elastic tooth unit bit, comprising a bit base body 1, a plurality of fixed PDC bit cutting teeth 21, a plurality of adaptive elastic PDC bit cutting teeth 32, and a plurality of bit gage groups 4;

[0051] The plurality of adaptive elastic PDC bit cutting teeth 32 are uniformly distributed on the upper end of the bit base body 1 through the adaptive elastic elements 31, the fixed PDC bit cutting teeth 21 are distributed at intervals between the adjacent two adaptive elastic PDC bit cutting teeth 32, and the plurality of bit gage groups 4 are uniformly distributed on the inner and outer sides of the adaptive elastic PDC bit cutting teeth 32 and the fixed PDC bit cutting teeth 21;

[0052] The adaptive elastic element 31 comprises an adaptive elastic element joint 3101, an adaptive elastic element buckle 3102, and an adaptive elastic element disc spring 3103, the adaptive elastic element buckle 3102 is fixedly connected with the bit base body 1, the adaptive elastic element joint 3101 is buckled to the bit base body 1 through the adaptive elastic element buckle 3102, the adaptive elastic element joint 3101 can slide up and down at the protrusion of the bit base body 1, the adaptive elastic element disc spring 3103 is fixedly connected with the bit base body 1 at the lowermost part, and the adaptive elastic element disc spring 3103 is fixedly connected with the adaptive elastic element joint 3101 at the uppermost end; the adaptive elastic element disc spring 3103 is fixedly connected together by a plurality of disc springs in positive and negative alternation; a flexible filling is filled between the adaptive elastic element joint 3101 and the bit base body 1, the height of the flexible filling is less than or equal to the maximum height of the adaptive elastic element disc spring 3103, the flexible filling material is an elastic material of rubber, and the flexible filling functions to further fix the relative position of the adaptive elastic element disc spring 3103 and prevent mud and cuttings from entering the gap between the bit base body 1 and the adaptive elastic element buckle 3102, so that the adaptive elastic element buckle 3102 cannot be lowered, and the whole adaptive elastic element 31 is disabled;

[0053] The back rake angle of the adaptive elastic PDC bit cutting tooth 32 is β0, and the back rake angle of the fixed PDC bit cutting tooth 21 is β1, wherein β0 is set to be between 0° and 10°, β1 is set to be between 15° and 25°, and β0 < β1;

[0054] The fixed PDC bit cutting tooth 21 and the adaptive elastic PDC bit cutting tooth 32 refer to bit tooth units that break rocks in a cutting manner mainly by shearing action, and are superhard cutting materials, such as polycrystalline diamond compacts or Si-Mn alloy series spring steels or hard alloy teeth, etc.

[0055] The adaptive elastic element joint 3101 and the adaptive elastic element buckle 3102 are made of spring steel material;

[0056] When the drill bit is not working, the difference between the bottom end surface of the adaptive elastic PDC drill bit cutting tooth 32 and the bottom end surface of the fixed PDC drill bit cutting tooth 21 is h.

[0057] The working principle and process of the embodiment are as follows:

[0058] The main purpose is to improve the adaptability of the drill bit to the formation, and to solve the problems of low drilling efficiency of the drill bit and easy damage of the drill bit teeth when drilling in complex formations such as soft and hard interbedded formations and formations containing large gravel. For details, please refer to Figures 1-11 As shown in the figure, when drilling in relatively soft formation, the drilling pressure does not need to be too large to drill, at this time only the adaptive elastic PDC drill bit cutting tooth 32 is working, cutting relatively soft rock. When drilling in relatively hard formation, the drill bit cutting is difficult, at this time the drilling pressure is increased, the adaptive elastic element disc spring 3103 is contracted, the adaptive elastic PDC drill bit cutting tooth 32 is lowered as a whole until it is flush with the fixed PDC drill bit cutting tooth 21, at this time the fixed PDC drill bit cutting tooth 21 participates in drilling and plays a main rock breaking role, and the adaptive elastic PDC drill bit cutting tooth 32 performs auxiliary drilling. Further, when drilling in relatively soft formation again, at this time the drilling pressure can be reduced to release the elastic force of the adaptive elastic element disc spring 3103, so that the adaptive elastic PDC drill bit cutting tooth 32 rises again and plays a main rock breaking role.

[0059] According to research, the angle of the rear inclination of the PDC drill bit is different when the rock breaking efficiency is the highest when breaking different rocks. When breaking soft rocks, the angle of the rear inclination is between 0° and 15°, and when breaking hard rocks, the angle of the rear inclination is between 15° and 25°. Therefore, in this embodiment, the angle of the rear inclination of the adaptive elastic PDC drill bit cutting tooth 32 is β0, and the angle of the rear inclination of the fixed PDC drill bit cutting tooth 21 is β1, wherein β0 is between 0° and 15°, β1 is between 15° and 25°, and β0 < β1. Therefore, the advantageous effect of this structure is that the angle of the cutting tooth can be adaptively adjusted according to different drilled rock layers. When cutting soft rocks, small drilling pressure is used, and the adaptive elastic PDC drill bit cutting tooth 32 with a small angle of the rear inclination is used for cutting. When cutting hard rocks, the drilling pressure is increased, the adaptive elastic PDC drill bit cutting tooth 32 with a small angle of the rear inclination is retracted for auxiliary drilling, the fixed PDC drill bit cutting tooth 21 with a large angle of the rear inclination is exposed, and the main rock breaking function is achieved, thereby achieving the purpose of adapting to the stratum. Further, the movement trajectory of the adaptive elastic PDC drill bit cutting tooth 32 is in the vertical direction, so that the adaptive process of the drill bit tooth unit does not change the inner and outer diameters of the drill bit, thereby ensuring the quality of the drilling. Further, the adaptive elastic element joint 3101 cooperates with the adaptive elastic element buckle 3102 to prevent the adaptive elastic PDC drill bit cutting tooth 32 from falling off during tripping. Further, the existence of the adaptive elastic element disc spring 3103 can adapt the cutting depth of the adaptive elastic PDC drill bit cutting tooth 32 during drilling, provide a buffer for the adaptive elastic PDC drill bit cutting tooth 32, achieve a damping effect, thereby reducing the impact damage of the polycrystalline diamond compact and improving the service life of the drill bit. Further, the height h of the adaptive elastic element disc spring 3103 can be controlled by adjusting the spring parameters and the number of springs, and the drilling pressure that causes the adaptive elastic PDC drill bit cutting tooth 32 to adaptively change can be controlled.

[0060] Embodiment two: as shown in the figure, different from example one in that: Figures 12-15

[0061] The fixed PDC drill bit cutting tooth 21 is replaced by a fixed impregnated diamond drill bit tooth 22, and the adaptive elastic PDC drill bit cutting tooth 32 is replaced by an adaptive elastic impregnated diamond drill bit tooth 33.

[0062] In this embodiment, the fixed impregnated diamond drill bit tooth 22 and the adaptive elastic impregnated diamond drill bit tooth 33 differ in the number of ring teeth. According to research, the optimal number of ring teeth of the impregnated diamond drill bit is different when the rock breaking efficiency is the highest when breaking different rocks. Therefore, this embodiment designs suitable impregnated diamond drill bit tooth units for soft rocks and hard rocks, respectively. The number of ring teeth of the fixed impregnated diamond drill bit tooth 22 is four, and the number of ring teeth of the adaptive elastic impregnated diamond drill bit tooth 33 is three.​

[0063] Specifically, the fixed impregnated diamond drill bit tooth 22 is integrally sintered with the drill bit base 1 to form a fixed connection. The self-adaptive elastic impregnated diamond drill bit tooth 33 is welded with the self-adaptive elastic element 31 to form a fixed connection, and is connected with the drill bit base 1 through the self-adaptive elastic element 31, and can be self-adaptively adjusted in height according to the drilling pressure, so that the self-adaptive elastic impregnated diamond drill bit tooth 33 plays a main rock breaking role when drilling soft rock; when drilling hard rock, the drilling pressure is increased, so that the height of the self-adaptive elastic impregnated diamond drill bit tooth 33 is reduced, the fixed impregnated diamond drill bit tooth 22 is exposed to play a main rock breaking role, and the self-adaptive elastic impregnated diamond drill bit tooth 33 plays an auxiliary rock breaking role; further, the existence of the disc spring 3103 of the self-adaptive elastic element can make the self-adaptive elastic drill bit tooth unit 3 adaptively adjust the grinding depth during drilling, provide a buffer for the self-adaptive elastic drill bit tooth unit 3, achieve a damping effect, thereby reducing the impact damage of the impregnated diamond drill bit tooth unit and improving the service life of the drill bit.

[0064] Embodiment three: as shown in the figure, different from embodiment one is that the fixed PDC drill bit cutting tooth 21 in the fixed drill bit tooth unit 2 is replaced by the fixed impregnated diamond drill bit tooth 22. Figures 16-19

[0065] This embodiment is mainly used when the physical and mechanical properties of soft rock and hard rock are greatly different. When drilling in soft rock stratum, the self-adaptive elastic PDC drill bit cutting tooth 32 rapidly breaks rock in a cutting manner; when drilling in hard rock stratum, the drilling pressure is increased, the self-adaptive elastic PDC drill bit cutting tooth 32 is retracted, and the fixed impregnated diamond drill bit tooth 22 is exposed to break hard rock in a mainly grinding manner; the number of the fixed impregnated diamond drill bit tooth 22 ring teeth is three.

[0066] The fixed impregnated diamond drill bit tooth 22 is integrally sintered with the drill bit base 1 to form a fixed connection, and the existence of the disc spring 3103 of the self-adaptive elastic element can make the self-adaptive elastic PDC drill bit cutting tooth 32 adaptively adjust the cutting depth during drilling, provide a buffer for the self-adaptive elastic PDC drill bit cutting tooth 32, achieve a damping effect, thereby reducing the impact damage of the polycrystalline diamond compact and improving the service life of the drill bit.​

Claims

1. A self-adapting elastic tooth unit bit for soft and hard interbedded formation, characterized in that: The drill bit comprises a drill bit base (1), a plurality of fixed drill bit tooth units (2), a plurality of adaptive elastic drill bit tooth units (3) and a plurality of drill bit gage pads (4). The plurality of adaptive elastic drill bit tooth units (3) are uniformly distributed on the upper end of the drill bit base (1) through adaptive elastic elements (31), the fixed drill bit tooth units (2) are distributed between two adjacent adaptive elastic drill bit tooth units (3), and the plurality of drill bit gage pads (4) are uniformly distributed on the inner and outer sides of the adaptive elastic drill bit tooth units (3) and the fixed drill bit tooth units (2). The adaptive elastic element (31) comprises an adaptive elastic element connector (3101), an adaptive elastic element buckle (3102) and an adaptive elastic element disc spring (3103), the adaptive elastic element buckle (3102) is fixedly connected with the drill bit base (1), the adaptive elastic element connector (3101) is buckled to the drill bit base (1) through the adaptive elastic element buckle (3102), the adaptive elastic element connector (3101) can slide up and down at the protrusion of the drill bit base (1), the adaptive elastic element disc spring (3103) is fixedly connected with the drill bit base (1) at the lowermost position, and the adaptive elastic element disc spring (3103) is fixedly connected with the adaptive elastic element connector (3101) at the uppermost position.

2. The self-adapting elastic tooth unit bit for soft and hard interbedded strata according to claim 1, characterized in that: The adaptive elastic element disc spring (3103) is fixedly connected by a plurality of disc springs in positive and negative alternation.

3. The self-adapting elastic tooth unit bit for soft and hard interbedded strata according to claim 1, characterized in that: The adaptive elastic element connector (3101) and the drill bit base (1) are filled with flexible filling, the height of the flexible filling is less than or equal to the maximum height of the adaptive elastic element disc spring (3103), and the flexible filling material is an elastic material of rubber.

4. The self-adapting elastic tooth unit bit for soft and hard interbedded strata according to claim 1, characterized in that: The back rake angle of the adaptive elastic drill bit tooth unit (3) is β0, and the back rake angle of the fixed drill bit tooth unit (2) is β1, wherein β0 is set to be between 0° and 15°, β1 is set to be between 15° and 25°, and β0 < β1.

5. The self-adapting elastic tooth unit bit for soft and hard interbedded strata according to claim 1, characterized in that: When the drill bit is not working, the difference between the bottom end surface of the adaptive elastic drill bit tooth unit (3) and the bottom end surface of the fixed drill bit tooth unit (2) is h.

6. The self-adapting elastic tooth unit bit for soft and hard interbedded strata according to claim 1, characterized in that: The fixed drill bit tooth unit (2) is a fixed PDC drill bit cutting tooth (21), and the adaptive elastic drill bit tooth unit (3) is an adaptive elastic PDC drill bit cutting tooth (32). When drilling in soft strata, only the adaptive elastic PDC drill bit cutting tooth (32) works to cut soft rocks, when drilling in hard strata, the drilling pressure is increased to make the adaptive elastic element disc spring (3103) contract, so that the adaptive elastic PDC drill bit cutting tooth (32) drops as a whole until it is flush with the fixed PDC drill bit cutting tooth (21), at this time, the fixed PDC drill bit cutting tooth (21) participates in drilling and plays a major role in rock breaking, and the adaptive elastic PDC drill bit cutting tooth (32) assists in drilling, when drilling in soft strata again, the drilling pressure is reduced to release the elastic force of the adaptive elastic element disc spring (3103), so that the adaptive elastic PDC drill bit cutting tooth (32) rises again to play a major role in rock breaking.

7. The self-adapting elastic tooth unit bit for soft and hard interbedded strata according to claim 1, characterized in that: The fixed drill bit tooth unit (2) is a fixed impregnated diamond drill bit tooth (22), and the self-adapting elastic drill bit tooth unit (3) is a self-adapting elastic PDC drill bit cutting tooth (32); when drilling in a soft rock stratum, the self-adapting elastic PDC drill bit cutting tooth (32) rapidly breaks rocks in a cutting manner; when drilling in a hard rock stratum, the drilling pressure is increased, the self-adapting elastic PDC drill bit cutting tooth (32) is contracted, the fixed impregnated diamond drill bit tooth (22) is exposed, and the hard rock is broken in a mainly grinding manner, and the number of ring teeth of the fixed impregnated diamond drill bit tooth (22) is three.

8. The self-adapting elastic tooth unit bit for soft and hard interbedded strata according to claim 1, characterized in that: The fixed drill bit tooth unit (2) and the self-adapting elastic drill bit tooth unit (3) are all polycrystalline diamond compacts, Si-Mn alloy series spring steels or hard alloys.

9. The self-adapting elastic tooth unit bit for soft and hard interbedded strata of claim 1, wherein: The self-adapting elastic element joint (3101) and the self-adapting elastic element buckle (3102) are spring steel materials.

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