PDC drill bit

Abstract

The utility model relates to the technical field of PDC drill bits, in particular to a PDC drill bit which comprises a drill bit base body, a plurality of cutting blades circumferentially arranged on the crown of the drill bit base body and cutting teeth arranged on the cutting blades, each cutting blade comprises a positive cutting part, and the positive cutting parts are gradually away from the hole bottom of a drill hole outwards in the radial direction of the drill bit base body. A plurality of cutting teeth arranged on the positive cutting part are gradually away from the hole bottom of the drill hole outwards in the radial direction of the drill bit base body, and slots are formed in the peripheral walls of the cutting teeth in the rotating direction in a penetrating mode. The formed conical cutting face can promote drilling fluid to directly flow back to the annulus position, so that the drilling fluid instantly drives chippings to flow towards the annulus at the back flushing moment, and the problem that the drilling fluid flows towards the annulus due to additional turbulent flow generated after back flushing in the horizontal cutting face is avoided. And a plurality of cutting teeth arranged on the positive cutting part are gradually far away from the hole bottom of the drill hole outwards in the radial direction of the drill bit base body, so that rock chippings fall off more easily under the cutting acting force, and the cutting efficiency is further guaranteed.

Description

Technical Field

[0001] This application relates to the field of PDC drill bit technology, and more particularly to a PDC drill bit. Background Technology

[0002] PDC drill bits, or polycrystalline diamond composite drill bits, are a type of fixed-cutting-tooth drill bit widely used in oil, natural gas, coal, and geological exploration. They use synthetic polycrystalline diamond (PDC) as cutting teeth and feature high wear resistance, high mechanical drilling speed, and long service life, making them particularly suitable for drilling operations in medium-hard to hard formations.

[0003] Patent document CN221957523U discloses a PDC drill bit, including a drill bit body, cutter blades, and cutting teeth. The end face of the cutting edge makes an angle of 1°-15° with the axis of the drill bit body, so that the end face of the cutting edge is inclined towards the drill bit body. Thus, when the drill bit rotates towards the formation, the cutting teeth change from the traditional scraping and rock breaking method to a plowing method, which makes it easier to penetrate the formation and reduces the phenomenon of drill bit slipping in place. This greatly improves drilling efficiency in plastic formations and saves drilling costs, which has certain positive significance. However, when this type of PDC drill bit is drilling, because the cutting teeth near the bottom of the hole are in frictional contact with the bottom of the hole at the same time, a horizontal cutting surface is often formed at the bottom of the hole. The horizontal cutting surface is not conducive to chip removal, not conducive to the flow of drilling fluid backflow into the annulus, and also creates a large feed resistance on the cutting teeth, affecting drilling efficiency.

[0004] Therefore, there is an urgent need for a new type of PDC drill bit to solve the above problems. Utility Model Content

[0005] The purpose of this application is to provide a PDC drill bit to solve the above-mentioned problems.

[0006] To achieve the above objectives, the technical solution of this application is as follows:

[0007] A PDC drill bit includes: a drill bit body, a plurality of cutting blades arranged circumferentially on the crown of the drill bit body, and cutting teeth disposed on the cutting blades. The cutting blades include a positive cutting portion, which gradually moves away from the bottom of the drill hole along the radial direction of the drill bit body. A plurality of cutting teeth disposed on the positive cutting portion gradually move away from the bottom of the drill hole along the radial direction of the drill bit body. The outer peripheral wall of the cutting teeth is provided with a slot through the hole along the rotation direction.

[0008] Preferably, the cutting blade further includes a side cutting portion; the cutting teeth include main cutting teeth and side cutting teeth, the main cutting teeth are disposed in the main cutting portion, and the side cutting teeth are disposed in the side cutting portion.

[0009] Preferably, the corresponding cutting teeth on two adjacent cutting blades are staggered.

[0010] Preferably, the slot is a U-shaped slot, which is disposed on the main cutting tooth.

[0011] Preferably, the cutting teeth are provided with a first chamfer and a second chamfer, the first chamfer being 45 degrees and the second chamfer being 17 degrees, and the second chamfer being closer to the bottom of the drill hole than the first chamfer.

[0012] Preferably, the main cutting brushes are arranged in two rows on the area where the front cutting part and the side cutting part of the cutting blade connect.

[0013] Preferably, the drill bit body has a water passage hole at one end facing the bottom of the borehole, and an alloy nozzle is provided in the water passage hole.

[0014] Preferably, the sidewall of the drill bit base is provided with a spiral groove.

[0015] The PDC drill bit disclosed in this application forms a conical cutting surface that allows drilling fluid to flow directly back into the annulus. This causes the drilling fluid to carry cuttings toward the annulus immediately after backflushing, avoiding the problem of additional turbulence affecting the flow of drilling fluid to the annulus, as is the case with horizontal cutting surfaces. Several cutting teeth on the positive cutting section are arranged radially outward from the bottom of the borehole along the drill bit body. The cutting teeth on the positive cutting section are arranged in a stepped manner, thereby reducing cutting resistance and preventing the working surfaces of multiple cutting teeth from being on the same plane. This allows more longitudinal sections of rock to be exposed, making it easier for rock fragments to fall off under the cutting force, further ensuring cutting efficiency. Attached Figure Description

[0016] Figure 1 This is a schematic diagram of the overall structure of this application;

[0017] Figure 2 This is another schematic diagram of the overall structure of this application;

[0018] Figure 3 This is a top view of the overall structure of this application;

[0019] Figure 4 This is a schematic diagram of the cutting gear structure in this application;

[0020] Figure 5 This is a schematic diagram of the double chamfer structure in the cutting teeth of this application.

[0021] In the picture:

[0022] 1. Drill bit body; 2. Cutting blade; 20. Front cutting section; 21. Side cutting section; 3. Main cutting tooth; 30. Slot; 31. Side cutting tooth; 4. Water passage hole; 5. Spiral groove; 6. First chamfer; 7. Second chamfer. Detailed Implementation

[0023] The present application will now be described in further detail with reference to the accompanying drawings. The drawings are simplified schematic diagrams, illustrating only the basic structure of the present application, and therefore only show the components relevant to the present application.

[0024] like Figure 1-5 As shown, a PDC drill bit includes: a drill bit body 1, a plurality of cutting blades 2 arranged circumferentially on the crown of the drill bit body 1, and cutting teeth provided on the cutting blades 2. The cutting blades 2 include a positive cutting portion 20, which gradually moves away from the bottom of the drill hole along the radial direction of the drill bit body 1. A plurality of cutting teeth provided on the positive cutting portion 20 gradually move away from the bottom of the drill hole along the radial direction of the drill bit body 1. The outer peripheral wall of the cutting teeth is provided with a slot 30 through it along the rotation direction.

[0025] The positive cutting section 20 gradually moves away from the bottom of the drill hole radially outward along the drill bit base 1, thereby forming a conical surface during the rotation of the positive cutting section 20 to avoid the generation of a horizontal cutting surface that would affect drilling efficiency.

[0026] The conical cutting surface formed can cause the drilling fluid to flow directly back to the annulus, thereby allowing the drilling fluid to carry the cuttings toward the annulus immediately after backflushing, avoiding the problem of additional turbulence affecting the flow of drilling fluid toward the annulus, as is the case with horizontal cutting surfaces.

[0027] The cutting teeth on the positive cutting part 20 are arranged radially outward from the bottom of the drill hole along the drill bit base 1. The cutting teeth on the positive cutting part 20 are arranged in a stepped manner, thereby reducing cutting resistance and avoiding the working surfaces of multiple cutting teeth being on the same plane, so that more longitudinal sections of the rock can be exposed, making it easier for rock fragments to fall off under the cutting force, and further ensuring cutting efficiency.

[0028] The cutting teeth are columnar and are welded onto the cutting blade 2.

[0029] The slot 30 penetrates both end faces of the cutting tooth and is located on the outer peripheral wall of the cutting tooth. The slot 30 can increase the friction between the cutting tooth and the bottom of the drill hole, thereby effectively preventing the cutting tooth from slipping during rotation and thus increasing the cutting speed.

[0030] The drill bit body 1 is made of high-quality carbon steel and is integrally machined on a five-axis lathe machining center. Its drill bit crown is a five-wing double-row tooth, the side cutting teeth 31 can be made of diamond composite material type 1308, and the main cutting teeth 3 can be made of PDC1613 type.

[0031] In some further embodiments, the cutting blade 2 also includes a side cutting portion 21; the cutting teeth include a main cutting tooth 3 and a side cutting tooth 31, the main cutting tooth 3 being disposed in the main cutting portion 20 and the side cutting tooth 31 being disposed in the side cutting portion 21.

[0032] In addition to the main cutting section 20, the cutting blade 2 also includes a side cutting section 21. The cutting teeth are divided into main cutting teeth 3 and side cutting teeth 31. The main cutting teeth 3 are located in the main cutting section 20 and are responsible for the main drilling work. Because the main cutting section 20 gradually moves away from the bottom of the borehole radially outward along the drill bit body 1, the main cutting teeth 3 can more effectively penetrate the formation during drilling, reducing slippage. The side cutting teeth 31 are located in the side cutting section 21, which can trim the well wall to ensure its regularity. This division of labor between the main cutting teeth 3 and the side cutting teeth 31 allows the drill bit to efficiently penetrate the formation while ensuring well wall quality, improving the overall drilling operation efficiency.

[0033] In some further embodiments, the corresponding cutting teeth on two adjacent cutting blades 2 are misaligned.

[0034] The cutting teeth on adjacent cutting blades 2 are staggered. This staggered arrangement ensures that the cutting areas of each cutting tooth complement each other during drilling, avoiding blind spots. Simultaneously, the staggered arrangement distributes the load on the cutting teeth, reducing wear on individual teeth and increasing their service life. Furthermore, due to the staggered distribution of the cutting teeth, the drilling debris generated during drilling is more evenly distributed at the bottom of the hole, facilitating the drilling fluid to carry the debris out of the hole, improving cuttings removal efficiency, and thus increasing drilling efficiency.

[0035] In some further embodiments, the slot 30 is a U-shaped slot, which is disposed on the main cutting tooth 3.

[0036] In addition to increasing friction, the U-groove also increases the cutting edge length of the cutting teeth, enabling better rock breaking during drilling and improving drilling efficiency. Simultaneously, the U-groove guides drilling fluid flow across the surface of the cutting teeth, carrying away heat and debris, reducing wear, and extending the service life of the cutting teeth.

[0037] In other embodiments, the depth of the U-shaped groove may be 0.9 mm and the width may be 1 mm.

[0038] In some further embodiments, the cutting teeth are provided with a first chamfer 6 and a second chamfer 7, the first chamfer 6 being 45 degrees and the second chamfer 7 being 17 degrees, the second chamfer 7 being closer to the bottom of the borehole than the first chamfer 6.

[0039] The cutting teeth are equipped with a first chamfer 6 and a second chamfer 7. The first chamfer 6 is 45 degrees, and the second chamfer 7 is 17 degrees, with the second chamfer 7 being closer to the bottom of the borehole than the first chamfer 6. This double-chamfer design gives the cutting teeth better cutting performance and wear resistance during drilling. The 45-degree first chamfer 6 guides the cutting teeth as they enter the formation, making it easier for them to penetrate. The 17-degree second chamfer 7 increases the contact area between the cutting teeth and the formation, improving cutting efficiency. Simultaneously, because the second chamfer 7 is closer to the bottom of the borehole, it better protects the bottom of the cutting teeth during drilling, reducing bottom wear and extending the service life of the cutting teeth.

[0040] When dealing with hard rock formations, the combined effect of U-grooves and double chamfers can not only increase the feed rate, but also enhance the wear resistance and impact resistance of the cutting teeth.

[0041] In some further embodiments, the main cutting teeth 3 are arranged in double rows on the area where the front cutting portion 20 and the side cutting portion 21 of the cutting blade 2 connect.

[0042] During drilling, the area where the front cutting section 20 connects with the side cutting section 21 is a region with complex stress distribution, prone to wear and reduced cutting efficiency. The double-row main cutting teeth 3 increase the cutting capacity in this area, improving drilling efficiency. Simultaneously, the double-row main cutting teeth 3 distribute the load, reducing wear on individual cutting teeth and extending their service life. Furthermore, the double-row main cutting teeth 3 design ensures that even if one row of cutting teeth wears or is damaged during drilling, the other row can continue to operate, improving the reliability and stability of the drill bit.

[0043] In some further embodiments, the drill bit body 1 has a water passage hole 4 at one end facing the bottom of the borehole, and an alloy nozzle is provided in the water passage hole 4.

[0044] During drilling, drilling fluid is sprayed to the bottom of the hole through the water inlet 4 and the alloy nozzle, serving to cool the cutting teeth, remove cuttings, and lubricate the drill bit. The alloy nozzle has high wear resistance and corrosion resistance, enabling it to operate stably for extended periods in harsh drilling environments. By rationally designing the position and size of the water inlet 4 and the alloy nozzle, it is possible to ensure that the drilling fluid is evenly sprayed to all parts of the bottom of the hole, improving cooling and cuttings removal effects, thereby increasing drilling efficiency and extending the service life of the cutting teeth.

[0045] In other embodiments, the number of water passage holes 4 is six; in a further embodiment, five of the six water passage holes 4 are arranged radially on one side of the drill bit base 1 facing the bottom of the drill hole, and the specific hole diameter can be 6mm; the remaining one is located relatively in the middle, and the specific hole diameter can be 10mm.

[0046] In some further embodiments, the sidewall of the drill bit body 1 is provided with a spiral groove 5.

[0047] The spiral groove 5 can increase the flow of drilling fluid and cuttings.

[0048] In addition, in different embodiments, the welding elevation angle of the main cutting tooth 3 can be set to 19° to increase the cutting depth of the cutting tooth and thus improve drilling efficiency.

[0049] Obviously, the above embodiments are merely illustrative examples for clear explanation and are not intended to limit the implementation. Those skilled in the art will recognize that other variations or modifications can be made based on the above description. It is neither necessary nor possible to exhaustively list all possible implementations here. However, obvious variations or modifications derived therefrom are still within the scope of protection of this application.

Claims

1. A PDC drill bit, characterized by, include: The drill bit body (1), a plurality of cutting blades (2) arranged circumferentially on the crown of the drill bit body (1), and cutting teeth provided on the cutting blades (2). The cutting blades (2) include a positive cutting part (20). The positive cutting part (20) moves radially outward from the bottom of the drill hole along the drill bit body (1). A plurality of cutting teeth provided on the positive cutting part (20) move radially outward from the bottom of the drill hole along the drill bit body (1). The outer peripheral wall of the cutting teeth is provided with a slot (30) in the direction of rotation.

2. The PDC bit of claim 1, wherein, The cutting blade (2) also includes a side cutting section (21); the cutting teeth include a main cutting tooth (3) and a side cutting tooth (31), the main cutting tooth (3) is disposed in the main cutting section (20), and the side cutting tooth (31) is disposed in the side cutting section (21).

3. The PDC bit of claim 1, wherein, The corresponding cutting teeth on two adjacent cutting blades (2) are misaligned.

4. The PDC bit of claim 2, wherein, The slot (30) is a U-shaped slot, which is provided on the main cutting tooth (3).

5. The PDC bit of claim 1, wherein, The cutting teeth are provided with a first chamfer (6) and a second chamfer (7). The first chamfer (6) is 45 degrees and the second chamfer (7) is 17 degrees. The second chamfer (7) is closer to the bottom of the borehole than the first chamfer (6).

6. The PDC bit of claim 1, wherein, The main cutting teeth (3) are arranged in double rows on the area where the front cutting part (20) and the side cutting part (21) of the cutting blade (2) are connected.

7. The PDC drill bit according to claim 1, characterized in that, The drill bit body (1) has a water passage hole (4) at one end facing the bottom of the borehole, and an alloy nozzle is provided in the water passage hole (4).

8. The PDC bit of claim 1, wherein, The drill bit base (1) has a spiral groove (5) on its side wall.

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