Low-energy-consumption PDC drill bit

Abstract

A low-energy-consumption PDC drill bit comprises a drill bit body and a plurality of blades extending from the drill bit body, cutting elements and nozzles are arranged on the blades, and at least two steps are arranged on the cutting contour line of the drill bit, so that the drill bit with the structure can release the stress of rock at the bottom of a well, reduce the strength of the rock, reduce the rock breaking difficulty of the drill bit and improve the mechanical drilling speed of the drill bit; the step protruding rock ridges can restrain transverse vibration of the drill bit and improve the stability of the drill bit, so that the service life of the drill bit is prolonged, and the anti-drifting capacity of the drill bit in directional drilling is improved.

Description

Technical Field

[0001] The present invention belongs to the technical equipment fields of oil and gas drilling engineering, mine engineering, construction foundation engineering construction, geological drilling, tunnel engineering, hydrology and trenchless technology, etc., and particularly relates to a PDC bit with low energy consumption. Background Art

[0002] A diamond bit is a rock-breaking tool used in drilling engineering to break rocks and form a wellbore. A PDC bit relies on polycrystalline diamond compact (abbreviated as PDC tooth or cutting tooth), which has high hardness, wear resistance and self-sharpening properties, as a cutting element to shear and break rocks. The PDC bit has a high mechanical drilling rate, a long service life and a low drilling cost in soft to medium-hard formations, so it is widely used in the drilling of oil and gas wells.

[0003] Although the PDC tooth has high hardness, due to the limitations of its impact resistance and thermal wear resistance, when the PDC bit drills in hard formations, highly abrasive formations, and severely heterogeneous formations (such as hard and soft alternating interlayers, gravel-bearing formations, etc.), the ability of the PDC tooth to penetrate into the formation is insufficient, resulting in a significant reduction in the cutting efficiency and service life of the bit. At the same time, it is easy to cause the rapid wear and failure of the composite sheet, and one of the most typical failure forms is the impact spalling of the diamond layer of the composite sheet. The main reason for the spalling of the composite sheet is that the impact force borne by the cutting tooth comes from the vibration of the bit, including lateral vibration and axial vibration.

[0004] The US patent "Drill bit having enhanced stabilization features and method of use thereof" (Patent No.: US20120186879) discloses a drill bit with a wavy profile. In this patent, the body contour line of the drill bit is a continuous wavy curve, and the wavy curve includes multiple concave and convex regions. Cutting elements are arranged along the body contour line of the drill bit. The drill bit forms a continuous and smooth undulating bottom hole at the bottom of the well, and the length of the body contour line is extended to increase the contact area between the cutting element and the bottom hole rock. The lateral vibration of the drill bit is suppressed by the reaction force of the bottom hole rock on the drill bit, and the drilling stability of the drill bit is improved. However, in actual drilling, the drill bit is required to have high rock-breaking efficiency and a long service life. But this patent can only improve the stability of the drill bit and extend its service life, and cannot enhance the aggressiveness of the drill bit. Therefore, this drill bit still cannot solve the problem of drilling in hard formations, highly abrasive formations, and severely heterogeneous formations (such as hard and soft alternating interlayers, gravel-bearing formations, etc.).

[0005] Chinese Patent "A Diamond Bit" (CN201621183925.5) This invention discloses a diamond bit, which includes a bit body and several cutter wings extending from the bit body. Cutting elements are provided on the cutter wings. There is at least one annular blank zone around the center of the bit on the bit, and the cutter wings at the position of the annular blank zone are concave inward to form a circumferentially through groove. This invention can reduce the cutting energy consumption of the bit, improve the rock-breaking efficiency, simultaneously inhibit the lateral vibration of the bit, effectively reduce the impact failure of the cutting teeth of the bit, enhance the anti-drift ability of the bit in directional drilling, and can generate large-sized cuttings, improve the quality of geological logging, and improve the accuracy of analysis and judgment of downhole formation information under actual drilling conditions.

[0006] Chinese Patent "A Large-Cutting, Low-Power Consumption Diamond Bit" (CN201720556725.8) discloses a large-cutting, low-power consumption diamond bit, which includes a bit body, fixed cutter wings extending from the bit body, water channels, water holes or nozzles between the cutter wings, etc. A first group of cutting elements is provided at the front end of the fixed cutter wings. There is at least one annular blank zone around the center of the bit on the bit, and no first group of cutting elements is provided in the annular blank zone area. Its characteristics are that there are at least a pair of independent cutter wings separated by the annular blank zone on both sides of the annular blank zone, and the circumferential positions of the independent cutter wings are staggered from each other, providing a large-cutting, low-power consumption diamond bit, which can significantly increase the size of the broken cuttings, reduce the rock-breaking power consumption of the bit, improve the mechanical drilling speed and rock-breaking efficiency of the bit, and simultaneously enhance the drilling stability of the bit.

[0007] The crown profile shape is a very important structural feature of a diamond bit. The crown profile line of the bit, also known as the cutting profile line, can both macroscopically reflect the distribution position characteristics of the cutting elements on the bit and directly reflect the basic shape characteristics of the bottom hole cut by the bit. The crown profile line of a diamond bit is usually a smooth curve, in the shape of a parabola, including an inner cone, a crown top (nose), an outer cone, a shoulder, and a gauge part. When an external load causes the bit to have a tendency to move horizontally, the rock walls of the inner cone or the outer cone in the central area of the bit exert a force on the bit in the direction opposite to its horizontal movement direction to inhibit the lateral movement of the bit, which is beneficial to improving the stability of the bit.

[0008] Assume that there is a cutting plane on the drill bit that passes through the drill bit axis and a certain point on the drill bit (called the axis plane or axial plane passing through the point). When the drill bit rotates around its own axis under the condition of zero drilling speed, the contour line of the cutting element intersects with the cutting plane or axial plane to form an intersection line. The intersection line is the axial surface contour line of the cutting element. The axial surface contour lines of all cutting elements are brought together to form the bottom hole coverage map of the drill bit. In the bottom hole coverage map, an envelope curve tangent to the axial surface contour lines of all cutting units can be made, which is called the drill bit cutting contour line. The drill bit cutting contour line reflects the basic shape characteristics of the bottom hole drilled by the drill bit. The drill bit body contour line is a position curve reflecting the drill bit body in the bottom hole coverage map, which is an important characteristic curve of the diamond drill bit. It is worth pointing out that the drill blade body contour line and the blade cutting contour line should not include the drill gauge part. This is obtained from the definition of the blade cutting contour line and the body contour line. The main cutting teeth in the drill generally refer to the cutting elements with longitudinal cutting ability, while the gauge teeth of the gauge part do not have longitudinal cutting ability, so the main cutting does not include the gauge teeth. In this way, the blade cutting contour line and the body contour line should start from the drill center and end at the gauge teeth. The drill tooth surface refers to the surface formed by the intersection with the drill body after one rotation with the drill axis as the rotation center and the drill body contour line as the rotation radius.

[0009] In a PDC drill bit, the contour line of the PDC cutting tooth intersects with the cutting plane or the axial plane to form an intersection line, which is the axial surface contour line of the PDC cutting tooth. The axial surface contour lines of all PDC cutting teeth are brought together to form the bottom hole coverage map of the PDC drill bit. An envelope curve tangent to the axial surface contour lines of all PDC cutting teeth is made, which is the cutting contour line of the PDC drill bit. Summary of the invention

[0010] The purpose of the present invention is to propose a PDC drill bit with low energy consumption, release the stress of the bottom hole rock, reduce the rock strength, reduce the rock breaking difficulty of the drill bit, and increase the mechanical penetration rate of the drill bit. The raised rock ridges of the steps can suppress the lateral vibration of the drill bit and improve the stability of the drill bit, thereby extending the service life of the drill bit and improving the anti-drift ability of the drill bit in directional drilling.

[0011] The object of the present invention is achieved through the following technical solutions:

[0012] A low-energy consumption PDC drill bit comprises a drill bit body and a plurality of blades extending from the drill bit body, wherein the blades are provided with cutting elements and nozzles, and is characterized in that at least two steps are provided on the cutting contour line of the drill bit.

[0013] In the above solution, a low - energy - consumption PDC bit includes a bit body and several cutter wings extending from the bit body. Cutting elements and nozzles are provided on the cutter wings. It is characterized in that: at least 2 steps are provided on the cutting profile line of the bit. The 2 steps include 3 cases: 2 inner steps, 2 outer steps, and 1 inner step and 1 outer step. The inner step means that the cutting profile line gradually concaves inward towards the bit center, and its concave direction is opposite to the bit drilling direction. The outer step means that the cutting profile line gradually concaves inward towards the bit gauge area. A preferred implementation of the step is a shallow step. The shallow step means that its height H is not greater than 2.5D, where D is the average working height of the PDC cutting elements on the step surface. When the same - diameter circular - profile PDC cutting teeth are used on the step surface, D is the diameter of the cutting teeth; when special - shaped teeth, such as elliptical teeth, are used on the step surface, D is the average working height of the PDC cutting elements on the step surface. When the bit diameter is less than or equal to 152 mm, the height H of the shallow step is not greater than 1.5D, where D is the average working height of the PDC cutting elements on the step surface. This releases the stress of the bottom - hole rock, reduces the rock strength, reduces the rock - breaking difficulty of the bit, increases the mechanical penetration rate of the bit. The raised rock ridge of the step can suppress the lateral vibration of the bit, improve the stability of the bit, thereby extending the service life of the bit, enhancing the anti - drift ability of the bit in directional drilling. At the same time, large - sized cuttings can be formed in the step area, reducing the rock - breaking energy consumption of the bit, increasing the rock - breaking efficiency of the bit, and being beneficial to the judgment of the logging formation.

[0014] As an option, at least 2 shallow steps are provided on the cutting profile line of the bit. The cutting profile line of the bit in the step area forms a step profile line. The step profile line is composed of a step surface and a step side surface. The value range of the angle α between the step surface and the horizontal line is: │α│≤20°. The value range of the angle β between the step side surface and the vertical line is: │β│≤45°.

[0015] In the above solution, at least 2 shallow steps are provided on the cutting profile line of the bit. The cutting profile line of the bit in the step area forms a step profile line. The step profile line is composed of a step surface and a step side surface. When the step surface is a plane, the value range of the angle α between it and the horizontal line is: │α│≤20°. The value range of the angle β between the step side surface and the vertical line is: │β│≤45°. Refer to Figure 2 , it is stipulated that the angle α between the step surface 41A and the horizontal line is positive in the clockwise direction and negative otherwise. Defining the angle between the step surface and the horizontal line and the angle between the step side surface and the vertical line can increase the length of the cutting profile line of the bit, increase the tooth - setting density of the bit, thereby extending the service life of the bit.

[0016] As an option, at least 2 shallow steps are provided on the cutting profile line of the bit. The value range of the step width W is 0 < W≤6D, where D is the average diameter of the cutting elements.

[0017] In the above solution, at least two shallow steps are provided on the cutting profile of the drill bit. The value range of the step width W is 0 < W ≤ 6D, where D is the average diameter of the cutting element. Here, D is the average diameter of the PDC cutting element on the step surface. For the case where all the PDC cutting teeth on the step surface adopt a circular profile, the width D is equal to the diameter of the cutting tooth. The value range of the step width W is 0 < W ≤ 3D, where D is the average diameter of the PDC cutting element on the step surface. When the value of the step width W is at a smaller size, the step effect of the drill bit is more obvious, which is beneficial to improving the rock-breaking efficiency of the drill bit.

[0018] As an option, at least two inner shallow steps are provided in the inner cone region of the cutting profile of the drill bit.

[0019] In the above solution, at least two inner shallow steps are provided in the inner cone region of the cutting profile of the drill bit. Considering that the rock-breaking efficiency in the inner cone region of the drill bit is relatively low, especially the cutting teeth in the central region of the drill bit directly crush the rock, which will limit the rock-breaking efficiency of the whole drill bit. Setting the step region at the inner cone position of the drill bit will be beneficial to improving the rock-breaking efficiency of this region, thereby enhancing the drilling efficiency of the whole drill bit. Especially when the step is set at the central axis of the drill bit, the improvement effect is the most obvious.

[0020] As an option, at least one shallow step is provided in at least one of the inner cone or inner concave region of the cutting profile of the drill bit, and at least one shallow step is also provided in the region outside the inner cone or inner concave region.

[0021] In the above solution, at least one shallow step is provided in at least one of the inner cone or inner concave region of the cutting profile of the drill bit, and at least one shallow step is also provided in the region outside the inner cone or inner concave region. From the perspective of the comprehensive ability of the drill bit, shallow steps are respectively provided in the inner cone region and the region outside the inner cone. In this way, there are low-energy-consuming step characteristics at different cutting positions of the drill bit, improving the rock-breaking efficiency of the whole region of the drill bit. Among them, more than 80% of the shallow steps on the cutting profile of the drill bit are inner steps, and more than 80% of the shallow steps on the cutting profile of the drill bit are outer steps.

[0022] As an option, at least one circumferentially continuous ring groove is provided on the cutting profile of the drill bit.

[0023] In the above solution, when the drill bit works at the bottom of the well, an annular rock ridge is formed in the groove area. The constraints of the rock on both sides of the rock ridge are released, so the strength of the rock ridge itself is significantly reduced, which is equivalent to an isolated "wall". Whether it is crushed, scraped (sheared) or impact-crushed, the energy consumption required for crushing will be greatly reduced, and the crushing method tends to be volumetric crushing. The saved energy can be used to enhance the rock-breaking effect of other cutting teeth on the drill bit, thereby improving the rock-breaking efficiency of the drill bit. On the other hand, the grooves on the cutter wings of the drill bit body can restrain the lateral movement of the drill bit, thereby reducing the lateral vibration of the drill bit and improving the stability of the drill bit. In addition, the grooves on the cutter wings of the drill bit (especially the cutting teeth on the ports and side walls) can play a role in reducing the drift force of the drill bit, and the drift trend of the drill bit in directional drilling can be better restrained.

[0024] Alternatively, an impact rock-breaking structure is provided on the drill bit body, and impact teeth are provided on the impact rock-breaking structure.

[0025] In the above solution, an impact rock-breaking structure is provided on the drill bit body, and impact teeth are provided on the impact rock-breaking structure. In this solution, a pressure or impact force generating device is provided or connected above the moving cutting element, and the generated impact force (such as the impact force generated by the inertia of the impact hammer) acts on the moving cutting element, so that the moving cutting element can slide relative to the drill bit body, and the moving cutting element transmits the impact force to the stepped rock sample, enabling the stepped rock sample to be efficiently crushed (low-energy consumption volumetric crushing) without bearing the weight on bit. When the action position of the impact teeth is in the outer one-third area of the stepped rock sample, the impact crushing effect will be better.

[0026] Alternatively, a roller cone rock-breaking structure is provided on the drill bit body, and roller cone teeth are provided on the roller cone rock-breaking structure.

[0027] In the above solution, a roller cone rock-breaking structure is provided on the drill bit body, and roller cone teeth are provided on the roller cone rock-breaking structure. In this way, relying on two rock-breaking structures of the roller cone and PDC teeth to break the bottom of the well can improve the applicability of the drill bit to the formation, thereby broadening the application range of the drill bit. When the action position of the roller cone teeth is in the outer one-third area of the stepped rock sample, the static pressure rock-breaking effect will be better.

[0028] Alternatively, the cutting profile line of the drill bit includes 1 inner shallow step and 1 outer shallow step, and the inner shallow step and the outer shallow step form 1 convex area.

[0029] In the above solution, the cutting profile of the drill bit includes one inner shallow step and one outer shallow step, and the inner shallow step and the outer shallow step form an outward convex area. The outward convex area can be of various types such as flat bottom, bow-shaped, pointed bottom, etc. In this way, as the step cutting area increases, the stress release at the bottom of the well is more thorough, the rock breaking difficulty is greatly reduced, and at the same time, the lateral contact area between the drill bit and the bottom of the well is increased, which is beneficial to reducing the lateral vibration of the drill bit and improving the comprehensive performance of the PDC drill bit.

[0030] As an option, the value range of the distance L between the contour line of the drill bit body and the side surface of the step is: D / 4 ≤ L ≤ 3D / 4, where D is the average diameter of the cutting element.

[0031] In the above solution, the value range of the distance L between the contour line of the drill bit body and the side surface of the step is: D / 4 ≤ L ≤ 3D / 4, where D is the average diameter of the cutting element. This increases the distance between the step and the drill bit body, preventing broken rock chips and falling blocks from getting stuck on the side surface of the step, reducing the probability of the drill bit being stuck while generating the step effect, and increasing the safety performance of drilling.

[0032] As an option, special-shaped teeth are provided on the drill bit, and the special-shaped teeth include conical PDC teeth, axe-shaped teeth, Mercedes-Benz teeth or a combination of multiple tooth shapes.

[0033] In the above solution, special-shaped teeth are provided on the drill bit, and the special-shaped teeth include conical PDC teeth, axe-shaped teeth, Mercedes-Benz teeth or a combination of multiple tooth shapes. The special-shaped teeth can be placed at the root and on the surface of the step. The cutting teeth of different shapes match different formations, thus broadening the applicable range of the drill bit.

[0034] As an option, wide-edge teeth are provided on the drill bit body, and the wide-edge teeth are provided on the side surface and the surface of the step.

[0035] In the above solution, wide-edge teeth are provided on the drill bit body, and the wide-edge teeth are provided on the side surface and the surface of the step. The wide-edge teeth can increase the cutting area of the cutting teeth and reduce the height of the cutting teeth. Using wide-edge teeth can reduce the step height and form a shallow step.

[0036] The present invention has at least the following beneficial effects:

[0037] 1. The step cutting of the drill bit releases the stress of the rock at the bottom of the well, reduces the rock strength, decreases the rock breaking difficulty of the drill bit, and improves the mechanical drilling rate of the drill bit.

[0038] 2. Cone teeth and impact teeth are provided on the step surface, and large-sized rock chips can be formed in this area, reducing the rock breaking energy consumption of the drill bit, improving the rock breaking efficiency of the drill bit, and being beneficial to the judgment of the logging formation at the same time.

[0039] 3. The raised rock ridge after step cutting can suppress the lateral vibration of the drill bit, improve the stability of the drill bit, and thus extend the service life of the drill bit.

[0040] 4. The step cutting area can reduce the drift force of the drill bit, and the drift trend of the drill bit in directional drilling can be better suppressed. BRIEF DESCRIPTION OF THE DRAWINGS

[0041] Figure 1 3D view of the stepped PDC drill bit of the present invention;

[0042] Figure 2 3D view of the PDC drill bit with inner and outer steps;

[0043] Figure 3 Radial coverage diagram of the PDC drill bit of the present invention;

[0044] Figure 4 Schematic diagram of the included angle of the step contour line;

[0045] Figure 5 Schematic diagram of the coverage of the drill bit with special-shaped teeth;

[0046] Figure 6 Schematic diagram of the conical teeth placed in the outer one-third area of the step surface;

[0047] Figure 7 Schematic diagram of the impact rock-breaking structure;

[0048] Figure 8 Schematic diagram of the ring groove provided on the drill bit;

[0049] Figure 9 Schematic diagram of the special-shaped teeth placed on the step surface;

[0050] Figure 10 Schematic diagram of the ring groove provided in the inner cone area of the drill bit;

[0051] Figure 11 Schematic diagram of the impact rock-breaking structure provided in the ring groove area;

[0052] Figure 12 Schematic diagram of the inclination angle on the side of the step;

[0053] Figure 13 Radial coverage diagram of the PDC drill bit with inner and outer steps;

[0054] Figure 14 Radial coverage diagram of the PDC drill bit with inner and outer shallow steps;

[0055] Figure 15 Schematic diagram of the drill bit with wide blade teeth;

[0056] Figure 16 Schematic diagram of the outer convex area being bow-shaped;

[0057] Figure 17 Schematic diagram of the outer convex area being sharp-angled;

[0058] Figure 18 Schematic diagram of a flat bottom in the convex region

[0059] Figure 19 Schematic diagram of multiple steps arranged in the inner conical region of the drill bit

[0060] Figure 20 Schematic diagram of a rock-rolling structure with cone bits

[0061] Figure 21 Schematic diagram of one step arranged in the inner conical region and one step arranged outside the inner conical region

[0062] Figure 22 Schematic diagram of multiple external steps arranged

[0063] Figure 23 Top view of the drill bit

[0064] Identifications in the figure:

[0065] 1 - Drill bit body; 2 - Blade; 2 - Cutting element; 31 - Axe-shaped tooth; 32 - Tapered tooth; 33 - Mercedes tooth; 34 - Impact rock-breaking structure; 341 - Impact tooth; 35 - Wide-edge tooth; 4 - Step; 41 - First-level inner step; 42 - Second-level inner step; 43 - Third-level inner step; 41A - Step surface; 41B - Step side; 5 - External step; 51 - First-level external step; 52 - Second-level external step; 53 - Third-level external step; 6 - Nozzle; 7 - Convex region; 71 - Bow-shaped convex region; 72 - Sharp-corner convex region; 73 - Flat-bottom convex region; 8 - Rock; 81 - Raised rock ridge; 82 - Annular groove; A1 - Drill bit cutting contour line; A2 - Drill bit body contour line Detailed implementation mode

[0066] The following non-limiting embodiments are used to illustrate the present invention:

[0067] A low-energy consumption PDC drill bit, comprising a drill bit body 1 and a plurality of blades 2 extending from the drill bit body, with cutting elements 3 and nozzles 6 arranged on the blades, characterized in that: at least two steps 4 are arranged on the drill bit cutting contour line, and the two types of steps include two inner steps as shown in Figure 1 , 3 , 5, 6, 7, 23, two external steps as shown in Figure 22 , one inner step and one external step, as shown in Figure 2 , 14 , 15, 16, 17, 21

[0068] Preferably, there are at least two shallow steps 4 provided on the drill bit cutting profile line A1. The drill bit cutting profile line in the step area forms a step profile line, which is composed of a step surface 41A and a step side surface 41B. The value range of the angle α between the step surface 41A and the horizontal line is: │α│≤20°, and the value range of the angle β between the step side surface 41B and the vertical line is: │β│≤45°, as Figure 4 , 12 shown.

[0069] Preferably, there are at least two shallow steps provided on the drill bit cutting profile line A1. The value range of the step width W is 0 < W ≤ 6D, where D is the average diameter of the cutting element, as Figure 5 shown. The value range of the step width W is 0 < W ≤ 3D, where D is the average diameter of the PDC cutting element on the step surface, as Figure 7 shown.

[0070] Preferably, at least two inner shallow steps 4 are provided in the inner cone area of the drill bit cutting profile line A1. One of the inner steps 4 is provided in the center area of the drill bit, which is consistent with the micro-core drill bit, as Figure 8 , 9 , 11, 13 shown.

[0071] Preferably, at least one shallow step is provided in the inner cone or inner concave area of the drill bit cutting profile line, and at least one shallow step is also provided in the area outside the inner cone or inner concave area, as Figure 14 , 15 , 16 shown.

[0072] Preferably, at least one circumferentially penetrating annular groove 82 is provided on the drill bit body 1. The annular groove and the protruding rock ridge 81 match each other, as Figure 8 , 9 , 10 shown. Impact teeth are provided in the area of the annular groove 82 to break the protruding rock ridge 81 by relying on the impact teeth, as Figure 11 shown.

[0073] Preferably, an impact rock-breaking structure 34 is provided on the drill bit body 1, and impact teeth 341 are provided on the impact rock-breaking structure 34, as Figure 7 shown. When the acting position of the impact teeth 341 is in the outer one-third area of the stepped rock sample, as Figure 7 shown.

[0074] Preferably, a roller cone rock-breaking structure 9 is provided on the drill bit body 1, and roller cone teeth 10 are provided on the roller cone rock-breaking structure 9. The acting position of the roller cone teeth 10 is in the outer one-third area of the stepped rock sample, as Figure 20 shown.

[0075] Preferably, the cutting profile of the drill bit includes one inner shallow step and one outer shallow step, and the inner shallow step and the outer shallow step form an outwardly convex region, and the outwardly convex region is a flat bottom 73 as Figure 18 shown, the outwardly convex region is an arc 71 as Figure 16 shown, the outwardly convex region is an arc with a pointed bottom 72, as Figure 17 shown.

[0076] Preferably, the value range of the distance L between the contour line A2 of the drill bit body and the step side surface 41B is: D / 4 ≤ L ≤ 3D / 4, where D is the average diameter of the cutting element, as Figure 3 shown.

[0077] Preferably, special-shaped teeth are provided on the drill bit, and the special-shaped teeth include conical PDC teeth 32, ax-shaped teeth 31, Mercedes-Benz teeth 33 or a combination of multiple tooth shapes, such as Figure 3 、 5 、6 shown.

[0078] Preferably, wide-edge teeth 35 are provided on the drill bit body 1, and the wide-edge teeth 35 are provided on the step side surface and the step surface, such as Figure 15 、 16 、17 shown.

[0079] Preferably, more than 80% of the shallow steps on the cutting profile of the drill bit are inner steps, such as Figure 19 shown.

[0080] Preferably, more than 80% of the shallow steps on the cutting profile of the drill bit are outer steps, such as Figure 22 shown.

[0081] As mentioned above, it is not a restriction on the present invention in any form. Although the present invention has been disclosed through the above embodiments, it is not intended to limit the present invention. Any person skilled in the art, without departing from the scope of the technical solution of the present invention, can make some changes or modifications to the equivalent embodiments with equivalent changes by using the disclosed technical content. However, as long as it does not depart from the content of the technical solution of the present invention, any simple modification, equivalent change and modification made to the above embodiments according to the technical essence of the present invention still fall within the scope of the technical solution of the present invention.

Claims

1. A low-energy PDC drill bit, comprising a drill bit body, and a plurality of blades extending from the drill bit body, wherein the blades are provided with cutting elements and nozzles, characterized in that: At least two steps are arranged on the cutting contour line of the drill bit.

2. A low energy consumption PDC drill bit as claimed in claim 1, characterized in that: At least two shallow steps are arranged on the drill bit cutting contour line, and the drill bit cutting contour line in the step area constitutes a step contour line, and the step contour line is composed of a step surface and a step side surface. The value range of the angle α between the step surface and the horizontal line is: │α│≤20°, and the value range of the angle β between the step side surface and the vertical line is: │β│≤45°.

3. A low energy consumption PDC drill bit as claimed in claim 1, characterized in that: At least two shallow steps are arranged on the cutting contour line of the drill bit, and the value range of the step width W is 0<W≤6D, where D is the average diameter of the cutting element.

4. A low energy consumption PDC drill bit as claimed in claim 1, characterized in that: At least two inner shallow steps are arranged in the inner cone area of ​​the drill bit cutting contour line.

5. A low energy consumption PDC drill bit as claimed in claim 1, characterized in that: At least one shallow step is arranged in the inner cone or inner concave area of ​​the drill bit cutting contour line, and at least one shallow step is arranged in the area outside the inner cone or inner concave area.

6. A low energy consumption PDC drill bit as claimed in claim 1, characterized in that: At least one circumferentially penetrating annular groove is arranged on the cutting contour line of the drill bit.

7. A low energy consumption PDC drill bit as claimed in claim 1, characterized in that: An impact rock breaking structure is arranged on the drill bit body, and impact teeth are arranged on the impact rock breaking structure.

8. A low energy consumption PDC drill bit as claimed in claim 1, characterized in that: A cone rock breaking structure is arranged on the drill bit body, and cone teeth are arranged on the cone rock breaking structure.

9. A low energy consumption PDC drill bit as claimed in claim 1, characterized in that: The drill bit cutting contour line includes an inner shallow step and an outer shallow step, and the inner shallow step and the outer shallow step form an outer convex area.

10. A low energy consumption PDC drill bit as claimed in claim 1, characterized in that: The range of the distance L between the drill body contour line and the step side is: D / 4≤L≤3D / 4, where D is the average diameter of the cutting element.

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