Mixing drill bit for well drilling in hard formation with strong abrasiveness

Abstract

The invention discloses a mixed drill bit for well drilling in a hard formation with strong abrasiveness, which is used for prolonging the service life of the drill bit and improving the well drilling efficiency. The drill bit comprises a drill bit body and a plurality of blades. The plurality of blades are arranged on the crown part of the drill bit main body, a chip groove is formed between every two adjacent blades, and a fan-shaped water channel is arranged on each chip groove; cutting areas are arranged on the blades, natural diamonds are arranged on the faces, right facing the rock stratum, of the cutting areas, and the natural diamonds are embedded in the blades in a preset tooth arrangement mode; an internally-embedded granulation diamond is impregnated in the part, below the natural diamond, of the interior of the cutter wing; the central area of the crown part is provided with a cone inner cone structure which is concave inwards, an inner water channel is arranged on the cone inner cone structure, and a triangular polycrystalline Balas is embedded on the conical surface of the cone inner cone structure.

Description

Technical Field

[0001] This application relates to the field of oil extraction drilling tools, and more particularly to a hybrid drill bit for drilling in highly abrasive hard formations. Background Technology

[0002] In oil and gas drilling operations, the drill bit, as the core tool that directly contacts and breaks rock formations, is a key factor determining drilling efficiency, cycle time, and cost. As exploration and development extend to deeper and unconventional areas, the formation conditions faced by drill bits are becoming increasingly complex, placing higher demands on the rock-breaking efficiency, wear resistance, and adaptability of drill bits to different operating conditions.

[0003] Especially when encountering highly abrasive hard formations such as gravelly quartz sandstone, basalt, and granite during drilling, the lithology exhibits characteristics of "relatively drillable upper part and extremely hard lower part" or "frequent alternation of soft and hard rock" with well depth. Existing conventional drill bits, such as PDC drill bits or natural diamond surface-mounted drill bits, can maintain a certain mechanical drilling rate in the upper formations, but once they enter highly abrasive hard rock sections, their cutting teeth wear accelerates rapidly, and their mechanical properties deteriorate quickly. While impregnated diamond drill bits, which are designed solely to improve wear resistance, have a longer lifespan, their mechanical drilling rate is relatively low when drilling into upper formations, making it difficult to meet the requirements of efficient operation.

[0004] Regardless of the type of drill bit mentioned above, when facing hard, abrasive formations, the central area of ​​the drill bit crown often suffers from insufficient density and weak wear resistance due to limited tooth space. This makes it prone to premature core wear failure, a phenomenon known as "core wear." This not only ends the drill bit's service life but also leads to frequent tripping and bit replacements, severely hindering the overall drilling progress.

[0005] Based on this, this application proposes a hybrid drill bit for drilling in highly abrasive hard formations to solve the above-mentioned technical problems. Summary of the Invention

[0006] To address the aforementioned technical problems, this application provides a hybrid drill bit for drilling in highly abrasive hard formations, which can improve drill bit lifespan and drilling efficiency.

[0007] The technical solution provided in this application is described below: This application provides a hybrid drill bit for drilling in highly abrasive hard formations, comprising: The drill bit body and multiple cutting blades; The plurality of cutting blades are disposed on the crown of the drill bit body, and a chip removal groove is formed between two adjacent cutting blades. A fan-shaped water channel is provided on the chip removal groove. The blade is provided with a cutting area, and a natural diamond is provided on the side of the cutting area facing the rock stratum. The natural diamond is inlaid on the blade by a pre-set tooth arrangement. Inside the blade wing, and below the surface-mounted natural diamond, there is an inlaid granulated diamond. The central region of the crown is provided with an inwardly recessed conical inner cone structure, the inner cone structure is provided with an inner water channel, and triangular polycrystalline balas are inlaid on the conical surface of the inner cone structure.

[0008] Optionally, the natural diamond is inlaid on the blade using a three-level concentric circular ridge inlaid tooth method. The three-level concentric circular ridge inlaid tooth method covers several groups of first tooth units. Each group of first tooth units includes a first blade, a second blade, and a third blade that are sequentially adjacent in the circumferential direction. The diamond tooth areas on the first blade, the second blade, and the third blade are arranged alternately in the circumferential direction of the drill bit. Furthermore, the distance between the diamond tooth area on the first cutting wing and the warp line of the drill body is S; The distance between the diamond toothed area on the second blade and the warp retainer is 2S / 3; The distance between the diamond toothed area on the third blade and the warp protection line is S / 3, where S is the spacing between two adjacent rows of natural diamonds on the same blade.

[0009] Optionally, in the three-level concentric ridge inlay method, the particle size of the natural diamond is N grade 5-8 particles / carat; The radial spacing of natural diamonds in the same blade is 4.2-5.0 mm, and the circumferential spacing is 3.9-4.5 mm.

[0010] Optionally, the natural diamond is inlaid on the blade in a two-level grid-like tooth arrangement, which covers several sets of second tooth units. Each set of second tooth units includes a fourth blade and a fifth blade that are sequentially adjacent in the circumferential direction. The distance between the grid-like toothed area of ​​the fourth blade and the diameter protection line of the drill bit is L; The distance between the grid-like toothed area of ​​the fifth blade and the diameter protection line is L / 2, where L is the distance between two adjacent rows of natural diamonds in the grid-like toothed area.

[0011] Optionally, in the two-level lattice arrangement, the particle size of the natural diamond is N-grade, 4-7 particles / carat; The radial spacing between adjacent natural diamonds in the same blade is 4.6-5.2 mm, and the circumferential spacing is 6.0-7.2 mm.

[0012] Optionally, the embedded granulated diamond includes large-particle granulated diamond and small-particle granulated diamond; The large-particle granulated diamond and the small-particle granulated diamond are mixed and filled into the blade wing in a preset ratio, wherein the large-particle granulated diamond has a size of 90ppc and the small-particle granulated diamond has a size of 150ppc.

[0013] Optionally, the cone apex half angle β of the cone structure inside the cone is 30-45 degrees.

[0014] Optionally, each diamond in the inlaid granulated diamond is surrounded by tungsten carbide powder.

[0015] Optionally, the cone surface of the inner cone structure is further inlaid with natural diamonds, and the particle size of the natural diamonds on the cone surface is 5-7 grains / carat.

[0016] Optionally, each of the cutting blades is provided with a reinforcing gauge layer behind it along the drilling direction, the reinforcing gauge layer being formed by inlaying several natural diamonds.

[0017] As can be seen from the above technical solutions, this application has the following beneficial effects: This application provides multiple blades 02 on the drill bit body 01, with a cutting area on each blade. Natural diamonds 05 are arranged in a pre-defined tooth pattern on the side of the cutting area facing the rock formation. Embedded granulated diamonds 06 are located inside the blades 02, below the surface natural diamonds 05. During drilling, the surface-mounted natural diamonds 05 first break the rock. When these diamonds wear down, the embedded granulated diamonds 06 inside the blades 02 take over the rock breaking. This improves service life and reduces the frequency of drill bit replacements. Compared to traditional drill bits, this application combines long service life with high drilling speed, meeting the demands of today's high-efficiency operations.

[0018] By setting an inwardly recessed conical internal cone structure 07 in the central area of ​​the crown of the drill bit body 01, and inlaying triangular polycrystalline balas on the cone surface of the conical internal cone structure 07, the rock strata in the core area can also be broken, reducing the situation where the drill bit core wears out first and also reducing the occurrence of "core removal". Attached Figure Description

[0019] Figure 1 This is a schematic diagram of a hybrid drill bit for drilling in highly abrasive hard formations according to this application; Figure 2 This is a top view schematic diagram of a hybrid drill bit for drilling in highly abrasive hard formations according to this application; Figure 3 This is a cross-sectional schematic diagram of a hybrid drill bit for drilling in highly abrasive hard formations according to this application; Figure 4This is a partially enlarged schematic diagram of a hybrid drill bit for drilling in highly abrasive hard formations according to this application; Figure 5 This is a schematic diagram of the three-level concentric circular ridge inlay tooth method of this application; Figure 6 This is a schematic diagram of the two-level lattice tooth arrangement method of this application; In the figure, the drill bit body is 01, the cutter blade is 02, the chip removal groove is 03, the fan-shaped water channel is 04, the natural diamond is 05, the granulated diamond is inlaid is 06, the cone structure inside the cone is 07, the internal water channel is 08, and the ridge groove is 09. Detailed Implementation

[0020] In this application, the terms "upper", "lower", "left", "right", "front", "rear", "top", "bottom", "inner", "outer", "middle", "vertical", "horizontal", "lateral", "longitudinal" and other terms indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only used to describe the relative positional relationship between the components or parts and do not specifically limit the specific installation orientation of each component or part.

[0021] Furthermore, in addition to indicating location or positional relationship, some of the aforementioned terms may also have other meanings. For example, the term "above" may also be used in some cases to indicate a certain dependency or connection relationship. Those skilled in the art can understand the specific meaning of these terms in this application based on the specific circumstances.

[0022] Furthermore, the terms "installation," "setup," "equipped with," "connection," and "linked" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral structure; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium, or an internal connection between two devices, components, or parts. Those skilled in the art can understand the specific meaning of these terms in this application based on the specific circumstances.

[0023] Furthermore, the structures, proportions, sizes, etc., drawn in the accompanying drawings of this application are only used to complement the content disclosed in the specification for those skilled in the art to understand and read, and are not intended to limit the conditions under which this application can be implemented. Therefore, they have no substantial technical significance. Any modification to the structure, change in the proportional relationship, or adjustment of the size, without affecting the effects and purposes that this application can produce, should still fall within the scope of the technical content disclosed in this application.

[0024] The technical solutions of this application will now be clearly and completely described with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0025] To address the shortcomings of traditional drill bits, such as short service life and susceptibility to core-hunting issues that affect drilling progress when dealing with rock formations exhibiting varying hardness with different drilling depths, this application proposes a hybrid-insertion drill bit for drilling in highly abrasive and hard formations. This design aims to improve drill bit life and drilling efficiency. The specific implementation structure of this application is described below: See Figures 1 to 6 This application provides an embodiment of a hybrid drill bit for drilling in highly abrasive hard formations, the embodiment comprising: The drill bit body 01 and multiple cutter wings 02 are provided on the crown of the drill bit body 01. A chip removal groove 03 is formed between two adjacent cutter wings 02, and a fan-shaped water channel 04 is provided on the chip removal groove 03. A cutting area is provided on the cutter wing 02, and a natural diamond 05 is provided on the side of the cutting area facing the rock stratum. The natural diamond 05 is inlaid on the cutter wing 02 by a pre-set tooth arrangement. Inside the cutter wing 02, and below the surface-mounted natural diamond 05, an inlaid granulated diamond 06 is embedded. The central area of ​​the crown is provided with an inwardly recessed conical internal cone structure 07. An internal water channel 08 is provided on the conical internal cone structure 07, and triangular polycrystalline balass is inlaid on the conical surface of the conical internal cone structure 07.

[0026] The front end of the drill bit body 01 is the crown, and the rear end is the connector for connecting the drill string. The drill bit body 01 has multiple (usually 6-12) cutting blades 02, which are radially fixed to the crown and are the main structure supporting the cutting teeth. The cutting blades 02 are integrally formed with or welded to the crown of the drill bit body 01.

[0027] The space formed between two adjacent blades 02 is a cuttings chute 03, used for the return of cuttings. A fan-shaped water channel 04 is provided in the cuttings chute 03, and a fan-shaped nozzle is provided in the fan-shaped water channel 04. The fan-shaped nozzle is connected to the internal water channel 08 system inside the drill bit body 01 for transporting drilling fluid.

[0028] In this embodiment, the main cutting element is a surface-mounted natural diamond 05 on the blade wing 02. The surface-mounted natural diamond 05 is inlaid on the surface of the cutting area of ​​the blade wing 02 according to a certain rule. The surface-mounted natural diamond 05 is partially embedded in the surface of the blade wing 02 and partially protrudes as a cutting edge through interference fit or brazing. The backup cutting element is an inlaid granulated diamond 06. The inlaid granulated diamond 06 exists in the base of the blade wing 02 in a padded manner (i.e., diamond particles are uniformly mixed in the matrix powder and sintered). It is located below the surface-mounted natural diamond 05.

[0029] Please continue reading. Figure 4 The inner cone structure 07 is located in the central region of the crown of the drill bit body 01. The inner cone structure 07 is an inwardly recessed conical surface. Triangular polycrystalline ballast is inlaid on the conical surface of the inner cone structure 07. The triangular polycrystalline ballast is fixed to the conical surface of the inner cone by sintering or brazing.

[0030] During drilling, the rock strata corresponding to the cone-shaped internal conical structure 07 are broken by triangular polycrystalline ballasts fixed on the conical concave surface, thus improving the wear resistance of the core and reducing the occurrence of "core hollowing". The cone-shaped internal conical structure 07 increases the space for tooth placement by increasing the curved area of ​​the core, and the triangular polycrystalline ballasts on it are specifically designed to break the rock in the core, solving the "core hollowing" problem.

[0031] An inner water channel 08 is provided in the central area of ​​the crown of the drill bit body 01. The inner water channel 08 penetrates the surface of the inner cone structure 07 of the cone and is also used to transport drilling fluid to cool the cutting teeth, carry cuttings, and clean the bottom of the well. There are 3 inner water channels 08.

[0032] During drilling, the surface-mounted natural diamond 05 utilizes its high hardness and sharp cutting edge to efficiently cut into and scrape the rock in the early stages of drilling, responsible for achieving a high mechanical drilling rate. When the surface-mounted natural diamond 05 wears down due to long-term wear, its efficiency decreases, or it is completely exhausted, the inlaid granulated diamond 06 particles wrapped in the matrix of the cutter wing 02 are continuously exposed as the matrix wears down, taking over to grind and break the rock, thereby greatly extending the effective working life of the drill bit.

[0033] Impregnation refers to the process of uniformly mixing fine, superhard abrasive grains (such as diamonds) into a matrix metal powder, then sintering them together to form a mold, thus encapsulating the superhard abrasive grains within the matrix. As the outer matrix is ​​worn away by rocks, new abrasive grains are continuously exposed and put to work, extending the wear-resistant life.

[0034] In this embodiment, multiple blades 02 are provided on the drill bit body 01, and a cutting area is provided on the blade 02. Natural diamonds 05 are arranged in a preset tooth pattern on the side of the cutting area facing the rock formation. In the interior of the blade 02, embedded granulated diamonds 06 are provided, located below the surface natural diamonds 05. In this way, during the drilling process, the surface-mounted natural diamonds 05 first break the rock formation. When the surface-mounted natural diamonds 05 are worn, the embedded granulated diamonds 06 inside the blade 02 take over the rock breaking. This can improve the service life and reduce the number of times the drill bit needs to be replaced. Compared with traditional drill bits, this application has both a long service life and a high drilling speed, meeting the current demand for efficient operation.

[0035] By setting an inwardly recessed conical internal cone structure 07 in the central area of ​​the crown of the drill bit body 01, and inlaying triangular polycrystalline balas on the cone surface of the conical internal cone structure 07, the rock strata in the core area can also be broken, reducing the situation where the drill bit core wears out first and also reducing the occurrence of "core removal".

[0036] Natural diamond 05 is inlaid on the blade 02 using a three-level concentric circular ridge inlaid tooth method. The three-level concentric circular ridge inlaid tooth method covers several groups of first tooth units. Each group of first tooth units includes a first blade, a second blade and a third blade that are sequentially adjacent in the circumferential direction. Among them, the diamond toothed areas on the first, second and third cutting wings are arranged alternately in the circumferential direction of the drill bit; Furthermore, the distance between the diamond toothed area on the first cutting wing and the warp protection line of the drill body 01 is S; The distance between the diamond toothed area on the second blade and the warp line is 2S / 3; The distance between the diamond toothed area on the third blade and the warp line is S / 3, where S is the spacing between two adjacent rows of natural diamond 05 on the same blade.

[0037] A basic layout unit consisting of three adjacent blades (first blade, second blade, and third blade) is called the first tooth-laying unit. Each blade 02 has a diamond tooth-laying area on its surface. In the diamond tooth-laying area, the distance between two adjacent rows of diamonds is S (the distance between two rows of diamonds located on adjacent concentric circles on the surface of blade 02), and the distance between two adjacent columns of diamonds (circumferential distance) is d.

[0038] The gage line refers to the outermost outline of the drill bit crown, where the cutting elements are used to maintain the diameter of the wellbore (i.e., gage protection). Natural diamond 05 can be inlaid here.

[0039] Please continue reading. Figure 5The distance between the diamond toothed area and the diameter protection line is actually the distance between the first row of natural diamond 05 and the diameter protection line. For example, in the first cutter wing, the distance between the first row of natural diamond 05 in the diamond toothed area on its surface and the diameter protection line is S; in the second cutter wing, the distance between the first row of natural diamond 05 in the diamond toothed area on its surface and the diameter protection line is 2S / 3; in the third cutter wing, the distance between the first row of natural diamond 05 in the diamond toothed area on its surface and the diameter protection line is S / 3.

[0040] On the cutting surfaces of these three cutter wings, the natural diamond 05 particles are not aligned, but rather staggered around the circumference of the drill bit. This arrangement ensures that as the drill bit rotates, the natural diamond 05 particles from different rings overlap and cover the bottom circumference, filling the cutting blind zone. Specifically, the cutting blind zone (rock ridge) caused by the gap between the two rows of natural diamond 05 particles on the first cutter wing is filled by the natural diamond 05 particles on the second and third cutter wings, solving the rock ridge problem caused by sparse tooth distribution, resulting in high and uniform crushing efficiency.

[0041] In the method of fixing the natural diamond 05, firstly, a raised annular groove 09 is machined on the blade 02, then the natural diamond 05 is inlaid and fixed in the groove 09, and finally, wear-resistant material is used to fill and reinforce the groove.

[0042] In this embodiment, the number of cutter wings 02 on the drill bit body 01 is a multiple of 3, such as 9 or 12. Each group of three adjacent cutter wings is called a first tooth-laying unit (each group of tooth-laying units is independent of each other). The diamonds on each group of first tooth-laying units are spatially staggered and continuously alternated in time (as the drill bit rotates), forming a dense, strong, and efficient rock-breaking network. When the drill bit rotates, the tracks formed by the natural diamonds 05 on the bottom rock intersect and cover each other evenly, avoiding cutting only on a fixed circumference, thereby improving rock-breaking efficiency and bottom-hole coverage.

[0043] In the three-level concentric ridge inlaid tooth method, the radial spacing and circumferential spacing are specifically defined. Specifically, in this optional embodiment, the particle size of natural diamond 05 in the three-level concentric ridge inlaid tooth method is N grade 5-8 particles / carat. The radial spacing of the natural diamonds 05 in the same blade 02 is 4.2-5.0 mm, and the circumferential spacing is 3.9-4.5 mm.

[0044] N-grade 5-8 diamonds / carat means there are 5 to 8 diamonds per carat. While ensuring a sufficient number of wear-resistant particles, it also takes into account the edge height and aggression of each diamond, making it suitable for extremely poor drillable formations, achieving a balance between lifespan and efficiency.

[0045] Please continue reading. Figure 6In a different embodiment from the three-level concentric ridge inlay method mentioned above, the natural diamond 05 is inlaid on the blade 02 in a two-level grid-like inlay method. The two-level grid-like inlay method covers several sets of second inlay units, and each set of second inlay units includes a fourth blade and a fifth blade that are sequentially adjacent in the circumferential direction. The distance between the grid-like toothed area of ​​the fourth cutter blade and the diameter protection line of the drill bit is L; The distance between the lattice-shaped toothed area of ​​the fifth blade and the diameter protection line is L / 2, where L is the distance between two adjacent rows of natural diamond 05 in the lattice-shaped toothed area.

[0046] A basic layout unit, called the second toothed unit, is composed of two adjacent blades 02 (the fourth blade and the fifth blade). The natural diamonds 05 on the two adjacent blades are also circumferentially misaligned.

[0047] Please continue reading. Figure 6 The distance between the grid-like toothed area and the diameter protection line is actually the distance between the front row of natural diamond 05 (the row closest to the diameter protection line and with the largest number of natural diamond 05) and the diameter protection line. For example, in the grid-like toothed area of ​​the fourth blade, the second row has the largest number of natural diamond 05, and the distance between the second row and the diameter protection line is L; while in the grid-like toothed area of ​​the fifth blade, the first row has the largest number of natural diamond 05, and the distance between the first row and the diameter protection line is L / 2. In this embodiment, when the distance between the first row (the row closest to the diameter protection line and with the largest number of natural diamond 05) and the diameter protection line in the fourth blade is L, the second row of the fifth blade has the largest number of diamonds and is close to the diameter protection line. Therefore, the distance between the second row of the fifth blade and the diameter protection line is L / 2, thus forming an effect of staggered arrangement on adjacent blades.

[0048] In the grid-like arrangement of teeth on the same blade 02, the first row closest to the diameter protection line has N natural diamond 05s (e.g., N=10), and the adjacent second row has N-1 (e.g., 9) or N+1 natural diamond 05s (e.g., 11). After determining N and N-1, the third and fourth rows follow the same pattern, with the number of natural diamond 05s alternating between N and N-1, or after determining N and N+1, the third and fourth rows follow the same pattern, with the number of natural diamond 05s alternating between N and N+1.

[0049] The spacing between two adjacent rows of natural diamonds 05 with the same number is L, that is, the spacing between the first and third rows is L, while the second row is at L / 2. In this embodiment, the number of natural diamonds 05 in the first row of two adjacent blades is different. For example, the number of natural diamonds 05 in the first row of the fourth blade is 9, and the number of natural diamonds 05 in the first row of the fifth blade is 10; and so on, the number of natural diamonds 05 in the second row of the fourth blade is 10, and the number of natural diamonds 05 in the second row of the fifth blade is 9.

[0050] In this optional embodiment, the particle size of natural diamond 05 in the two-level lattice tooth arrangement is 4-7 particles / carat of N grade; The radial spacing of adjacent natural diamonds 05 in the same blade 02 is 4.6-5.2mm, and the circumferential spacing is 6.0-7.2mm.

[0051] In this embodiment, the radial spacing of 4.6-5.2 mm and the axial spacing of 6.0-7.2 mm provide greater chip removal and cooling space for the natural diamond 05, reducing the risk of repeated cutting of rock chips and heat accumulation, and further supporting efficient cutting under high speed and high drill pressure.

[0052] Please continue reading. Figure 4 In an optional embodiment, the embedded granulated diamond 06 includes large granulated diamond particles and small granulated diamond particles. Large-particle granulated diamond and small-particle granulated diamond are mixed and filled into the blade 02 according to a preset ratio. The large-particle granulated diamond has a specification of 90ppc, and the small-particle granulated diamond has a specification of 150ppc.

[0053] In this embodiment, the embedded granulated diamond 06 is formed by mixing large particles (90ppc) and small particles (150ppc) in a certain preset ratio and then sintering them together with the matrix powder to form an embedded layer.

[0054] PPC (pieces per carat) refers to the number of pieces per carat; the smaller the number, the larger the pieces. Larger pieces offer higher cutting efficiency and stronger abrasiveness. Smaller pieces have better wear resistance, providing smoother grinding and a longer lifespan.

[0055] The preset ratios are as follows: For highly abrasive formations, small-particle granulated diamond (150 ppc) is used as the main component (accounting for 70%-80%), supplemented by large-particle granulated diamond (20%-30%), in order to improve wear resistance life.

[0056] For formations with weak abrasiveness, large-particle granulated diamond (90 ppc) is used as the main material (accounting for 70%-80%), supplemented by small-particle granulated diamond (20%-30%), in order to improve grinding efficiency.

[0057] In an optional embodiment, the cone apex half angle β of the inner cone structure 07 of the cone is 30-45 degrees.

[0058] In this embodiment, the cone apex half angle β specifically refers to the acute angle between the generatrix (side line) of the cone and the central axis of the cone on the cone axis section (i.e., the section passing through the central axis of the cone) of the cone internal cone structure 07.

[0059] An angle of 30-45 degrees can maximize the area of ​​tooth placement on the core cone surface while ensuring structural strength.

[0060] The cone structure 07 inside the cone has teeth on its cone surface, which can break the rock in the center during drilling, thus solving the traditional problem of core drilling.

[0061] In an optional embodiment, each diamond in the inlaid granulated diamond 06 is surrounded by tungsten carbide powder.

[0062] In this embodiment, each diamond particle used for inlay is pre-coated with a layer of tungsten carbide powder to form a "diamond-tungsten carbide" composite microsphere, which is then used for inlay.

[0063] Tungsten carbide forms a coating layer around the diamond particles, which prevents direct contact between the diamond particles and the diamonds, thus preventing them from agglomerating during mixing and sintering and ensuring extremely uniform distribution.

[0064] In an optional embodiment, the cone surface of the cone structure 07 inside the cone is further inlaid with natural diamonds 05, and the particle size of the natural diamonds 05 on the cone surface is 5-7 pieces / carat.

[0065] In this embodiment, in addition to triangular polycrystalline balas, natural diamond 05 is additionally inlaid on the conical surface of the inner cone. The size of the inlaid natural diamond 05 is 5-7 pieces / carat.

[0066] By combining triangular polycrystalline Balas with natural diamond 05, it is possible to more effectively cope with the complex multi-directional stress and rock changes in the core, further reduce the "core erosion" phenomenon, and improve the service life of the core area.

[0067] It should also be noted that natural diamonds 05 can be inlaid only on the cone surface of the cone structure 07 inside the cone, without using triangular polycrystalline balas. Specifically, three concentric annular grooves 09 are machined around the cone apex on the cone surface inside the cone. Natural diamonds 05 with a particle size of 5-7 pieces / carat are selected and inlaid one by one into the annular grooves 09 with an interference fit. Then, wear-resistant matrix material is used to reinforce the sides of the grooves 09 by brazing or sintering, so that the diamonds are firmly encased in the grooves 09.

[0068] In an optional embodiment, each blade 02 is provided with a reinforcing gauge layer behind it along the drilling direction, the reinforcing gauge layer being formed by inlaying a plurality of natural diamonds 05.

[0069] In this embodiment, one or more rows of natural diamonds 05 are additionally inlaid on the back of each cutter wing 02 (i.e., the outer cylindrical surface of the drill bit body 01, referred to as the gauge protection surface) to form a reinforced gauge protection layer, thereby directly resisting the grinding of the well wall and preventing the drill bit diameter from decreasing due to wear.

Claims

1. A hybrid drill bit for drilling in highly abrasive hard formations, characterized in that, include: The drill bit body and multiple cutting blades; The plurality of cutting blades are disposed on the crown of the drill bit body, and a chip removal groove is formed between two adjacent cutting blades. A fan-shaped water channel is provided on the chip removal groove. The blade is provided with a cutting area, and a natural diamond is provided on the side of the cutting area facing the rock stratum. The natural diamond is inlaid on the blade by a pre-set tooth arrangement. Inside the blade wing, and below the natural diamond, there is an embedded granulated diamond. The central region of the crown is provided with an inwardly recessed conical inner cone structure, the inner cone structure is provided with an inner water channel, and triangular polycrystalline balas are inlaid on the conical surface of the inner cone structure.

2. The mixed-lay drill bit according to claim 1, characterized in that, The natural diamond is inlaid on the blade using a three-level concentric circular ridge inlaid tooth method. The three-level concentric circular ridge inlaid tooth method covers several groups of first tooth units. Each group of first tooth units includes a first blade, a second blade, and a third blade that are sequentially adjacent in the circumferential direction. The diamond tooth areas on the first blade, the second blade, and the third blade are arranged alternately in the circumferential direction of the drill bit. Furthermore, the distance between the diamond tooth area on the first cutting wing and the warp line of the drill body is S; The distance between the diamond toothed area on the second blade and the warp retainer is 2S / 3; The distance between the diamond toothed area on the third blade and the warp protection line is S / 3, where S is the spacing between two adjacent rows of natural diamonds on the same blade.

3. The mixed-lay drill bit according to claim 2, characterized in that, In the aforementioned three-level concentric ridge inlaid tooth method, the particle size of the natural diamond is N grade 5-8 pieces / carat; The radial spacing of natural diamonds in the same blade is 4.2-5.0 mm, and the circumferential spacing is 3.9-4.5 mm.

4. The mixed-lay drill bit according to claim 1, characterized in that, The natural diamond is inlaid on the blade in a two-level grid-like tooth arrangement. The two-level grid-like tooth arrangement covers several sets of second tooth units. Each set of second tooth units includes a fourth blade and a fifth blade that are sequentially adjacent in the circumferential direction. The distance between the grid-like toothed area of ​​the fourth blade and the diameter protection line of the drill bit is L; The distance between the grid-like toothed area of ​​the fifth blade and the diameter protection line is L / 2, where L is the distance between two adjacent rows of natural diamonds in the grid-like toothed area.

5. The mixed-lay drill bit according to claim 4, characterized in that, In the two-level lattice-shaped tooth arrangement, the particle size of the natural diamond is N grade 4-7 particles / carat; The radial spacing between adjacent natural diamonds in the same blade is 4.6-5.2 mm, and the circumferential spacing is 6.0-7.2 mm.

6. The mixed-lay drill bit according to any one of claims 1 to 5, characterized in that, The embedded granulated diamonds include large-particle granulated diamonds and small-particle granulated diamonds. The large-particle granulated diamond and the small-particle granulated diamond are mixed and filled into the blade wing in a preset ratio, wherein the large-particle granulated diamond has a size of 90ppc and the small-particle granulated diamond has a size of 150ppc.

7. The mixed-lay drill bit according to any one of claims 1 to 5, characterized in that, The cone apex half angle β of the inner cone structure of the cone is 30-45 degrees.

8. The mixed-lay drill bit according to any one of claims 1 to 5, characterized in that, Each diamond in the inlaid granulated diamond is surrounded by tungsten carbide powder.

9. The mixed-lay drill bit according to any one of claims 1 to 5, characterized in that, The cone-shaped structure inside the cone is further inlaid with natural diamonds, with a diamond size of 5-7 diamonds per carat.

10. The mixed-lay drill bit according to any one of claims 1 to 5, characterized in that, Each of the cutting blades is provided with a reinforcing gauge layer at the rear along the drilling direction, the reinforcing gauge layer being formed by inlaying several natural diamonds.

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