Polycrystalline diamond cutting elements employing modified tungsten carbide matrix to improve thermal stability

Abstract

A cutting element includes: a substrate having a hard material and a binder; and a polycrystalline diamond mesa. At least a portion of the matrix has a thermal conductivity greater than 130 W / m DEG C. A polycrystalline diamond mesa is disposed on the interface surface of the substrate. Drill bits for earth boring include one or more such cutting elements.

Description

[0001] Cross-references to related applications This application claims priority to U.S. Provisional Patent Application No. 63 / 493,918, filed April 3, 2023, which is incorporated herein by reference in its entirety. Background Technology

[0002] This invention relates to cutting elements, such as those used in drill bits for drilling into the Earth's strata, and various methods for manufacturing such cutting elements.

[0003] Generally, methods for manufacturing cutting elements employ a cemented carbide matrix in which tungsten carbide particles are bonded together with a metal such as cobalt. The cemented carbide body is placed adjacent to a layer of superhard material particles (such as diamond or cubic boron nitride (CBN) particles) and a binder (such as cobalt), and encased in a refractory metal shell (often called a "can") (e.g., a niobium can), and the assembly is subjected to high temperature and pressure, where the diamond or CBN is thermodynamically stable. This is known as a sintering process. The sintering process results in recrystallization on the cemented carbide matrix and the formation of a PCD or PCBN superhard material layer; that is, it results in the formation of a cutting element with a cemented carbide matrix and a superhard material cutting layer. The superhard material layer may include tungsten carbide particles and / or a small amount of cobalt. Cobalt promotes the formation of PCD or PCBN. Cobalt can also infiltrate from the cemented carbide matrix into the diamond or CBN.

[0004] Hard alloy matrices are typically formed by placing tungsten carbide powder and a binder into a mold, then heating the binder to its melting temperature to melt and penetrate the tungsten carbide particles, fusing them together and bonding them to the matrix. Alternatively, the tungsten carbide powder can be bonded with a binder during a high-temperature, high-pressure sintering process for recrystallizing superhard material layers. In this case, the matrix material powder is placed together with the binder into a refractory metal shell. Superhard material particles are placed on top of the matrix material to form a polycrystalline superhard material layer. The entire assembly is then subjected to a high-temperature, high-pressure process to form a cutting element with a matrix and a polycrystalline superhard material layer thereon.

[0005] Currently, the most common method to improve the thermal stability of cutting elements is to form a TSP cutting layer by leaching to remove cobalt from the interstitial space. The current industry trend is to leach the diamond mesa as deep as possible, to a depth of 1 mm or more. However, catastrophic diamond failure can still occur in the tool once the leached layer wears away. Cutting elements that do not fail at higher operating temperatures and therefore have a longer service life are desirable. Summary of the Invention

[0006] Many embodiments described herein relate to a cutting element having a matrix comprising a hard material and a binder. The matrix may have an interfacial surface, wherein at least a portion of the matrix has a thermal conductivity greater than 130 W / m °C. Additionally, the interfacial surface has a polycrystalline diamond mesa.

[0007] In various implementations, the cutting element has an average grain size of hard material greater than 5 micrometers.

[0008] In other embodiments, the substrate has a thermal conductivity of at least 140 W / m℃.

[0009] In other embodiments, the substrate has a length and includes a first axial portion and a second axial portion above the first axial portion, wherein an interface surface is formed on the first axial portion, and wherein the first axial portion has a length not greater than 50% of the length of the substrate.

[0010] In other embodiments, the first axial portion has a lower thermal conductivity than the second axial portion.

[0011] In other embodiments, the first axial portion matrix contains more cobalt by weight than the second axial portion.

[0012] In some embodiments, the cutting element has a base length greater than 12.7 mm. The polycrystalline diamond mesa has a mesa thickness, wherein the cutting element length is the sum of the base length and the mesa thickness. Additionally, the base length is greater than 80% of the cutting element length.

[0013] In other embodiments, the adhesive comprises cobalt and nickel, wherein the cobalt comprises between 5% and 10% by weight of the matrix, and the nickel comprises between 1% and 4% by weight of the matrix.

[0014] In other embodiments, cobalt accounts for less than 8% by weight of the matrix, nickel accounts for between 1% and 2% by weight of the matrix, and the average particle size of the hard material is between 6 and 8 micrometers.

[0015] Other embodiments relate to a scraper drill bit having a plurality of blades and a plurality of cutting elements mounted on each blade. At least one of the cutting elements has a matrix comprising a hard material and a binder. The matrix has an interfacial surface, wherein at least a portion of the matrix has a thermal conductivity greater than 130 W / m °C. Additionally, the interfacial surface has a polycrystalline diamond mesa.

[0016] In various implementations, the average particle size of the hard material is between 6 and 8 micrometers.

[0017] In other embodiments, the substrate of at least one cutting element has a thermal conductivity of at least 140 W / m °C.

[0018] In other embodiments, the base of at least one cutting element has a length and has a first axial portion and a second axial portion above the first axial portion, wherein an interface surface is formed on the first axial portion, and wherein the first axial portion has a length not greater than 50% of the length of the base.

[0019] In various other embodiments, the first axial portion has a lower thermal conductivity than the second axial portion.

[0020] In other embodiments, the second axial portion includes a CoNi matrix containing between 5% and 7% cobalt and between 1% and 2% nickel.

[0021] In other embodiments, the average hard material particle size of the second axial portion is greater than the average hard material particle size of the first axial portion.

[0022] In some embodiments, the base length of at least one cutting element is greater than 12.7 mm, and the polycrystalline diamond mesa of at least one cutting element has a mesa thickness, and the cutting element length of at least one cutting element is the sum of the base length and the mesa thickness. Additionally, the base length of at least one cutting element is greater than 80% of the cutting element length.

[0023] In other embodiments, the adhesive comprises cobalt and nickel, wherein the cobalt comprises between 5% and 10% by weight of the matrix, and the nickel comprises between 1% and 4% by weight of the matrix.

[0024] In other embodiments, cobalt accounts for less than 8% by weight of the matrix, nickel accounts for between 1% and 2% by weight of the matrix, and the average particle size of the hard material is between 6 and 8 micrometers.

[0025] In some implementations, each blade includes only a single row of cutting elements.

[0026] This summary is provided to introduce a series of concepts further described in the detailed description. The summary is not intended to identify key or essential features of the claimed subject matter, nor is it intended to help limit the scope of the claimed subject matter. Additional features and aspects of embodiments of this disclosure will be set forth herein and will be apparent in part from the description, or may be learned by practice of such embodiments. Attached Figure Description

[0027] To describe how the above and other features of this disclosure are obtained, a more specific description will be presented by reference to the specific embodiments shown in the accompanying drawings. For better understanding, the same elements have been denoted by the same reference numerals throughout the drawings. While some of the drawings may be schematic or exaggerated representations of concepts, at least some of the drawings may be drawn to scale. It should be understood that the drawings depict some exemplary embodiments, which will be described and explained in more specific and detailed manner by means of the drawings, in which: Figure 1 This is a perspective view of the cutting element in the example implementation.

[0028] Figure 2 This is a perspective view of an example implementation of a scraper drill bit with two rows of cutting elements mounted on each blade.

[0029] Figure 3A This is a side view of the cutting element in another example implementation.

[0030] Figure 3B This is another example implementation of a cutting element side view.

[0031] Figure 4 This is a side view of the cutting element in another example implementation.

[0032] Figure 5 This is a perspective view of another example implementation of a scraper drill bit with a single row of cutting elements mounted on each blade. Detailed Implementation

[0033] This disclosure generally relates to thermally stabilized cutting elements and various methods for manufacturing such drill bits. Various embodiments may relate to a thermally stabilized cutting element having a matrix made of a hard material and a binder. The matrix may have an interface that is mated or connected to a polycrystalline diamond mesa at the interface. In many embodiments, a portion of the matrix has a thermal conductivity greater than 130 W / m °C.

[0034] When drilling with polycrystalline diamond (PCD) cutting elements, the diamond in contact with the rock formation must be kept below a critical temperature of approximately 700°C. Above this critical temperature, the diamond fails rapidly, and drilling performance deteriorates significantly. Therefore, thermally stable polycrystalline materials (TSPs) have been highly sought after in the industry. This is typically achieved by "leaching" cobalt from the diamond lattice structure of the PCD. During formation, a PCD consists of individual diamond crystals interconnected, defining its lattice structure. Cobalt particles are typically found within the interstices of the diamond lattice. Cobalt has a significantly different coefficient of thermal expansion than diamond, and therefore, when the PCD is heated, the cobalt expands, causing cracks to form in the lattice structure, leading to damage to the PCD layer. By removing (i.e., by leaching) cobalt from the diamond lattice structure, the PCD layer becomes more heat-resistant, i.e., more thermally stable. However, the polycrystalline diamond layer becomes more brittle. Therefore, in some cases, only selected portions of the PCD layer (measured by depth or width) are leached to achieve thermal stability without sacrificing impact resistance. TSP materials can also be formed by using thermally matched silicon carbide binders instead of cobalt to form PCD.

[0035] When cobalt is present and the PCD cutting tip reaches temperatures above 700°C during drilling, the differential thermal expansion between diamond and cobalt in the microstructure generates high stress. Additionally, the cobalt catalyst begins to convert diamond back into graphite. Therefore, the strength of the unleached PCD decreases rapidly at high temperatures. Removing cobalt from the diamond mesa through acid leaching makes the material more stable at high temperatures. Therefore, many embodiments described herein aim to improve the TSP diamond structure and achieve more thermally stable cutting tools.

[0036] For example, Figure 1 An embodiment of a cutting element 1 (such as a shearing tool) that can be mounted on a drilling bit is shown. Typically, the tool 1 may have a cylindrical cemented carbide body 10, i.e., a substrate, having an end face 12 (also referred to herein as an “interface surface”). A superhard material layer (also referred to herein as a mesa) 18, such as polycrystalline diamond (PCD), polycrystalline cubic boron nitride (PCBN), or thermally stabilized polycrystalline (TSP) material, may be bonded to and mated with the interface surface to form a cutting layer. In various embodiments, the substrate may have a flat, curved, or non-uniform interface surface 12. In some embodiments, a non-uniform interface surface may have peaks and valleys. Once formed according to the various embodiments described herein, the cutting element can be mounted in a recess 2 of a drilling bit (such as a scraper bit 7), such as... Figure 2 As shown, it contacts the formation along edge 9 during drilling.

[0037] In the example implementation, the PCD cutting element 1 (such as...) Figure 1The cutting element shown can be formed using a high thermal conductivity cemented carbide substrate during the PCD manufacturing process, resulting in a PCD cutting element having a high thermal conductivity substrate and a polycrystalline diamond mesa or layer 18. The diamond mesa can be bonded to the interface surface 12 of the substrate via a high-temperature, high-pressure (HPHT) sintering process. The interface surface can be planar (e.g., flat, such as...). Figure 3A (As shown), it can also be non-planar (i.e., curved, or non-uniform, with peaks and valleys, such as, for example) Figure 3B (As shown). The diamond mesa 18 may have a flat or planar upper surface 19 (i.e., a diamond mesa surface opposite to the diamond mesa surface that abuts against the matrix interface surface 12), such as, for example Figure 3A As shown, or a non-planar upper surface 19, such as, for example Figure 3B The dome surface is shown. In an example embodiment, the interface surface 12 may be planar, and the upper surface 19 of the diamond mesa may be non-planar. In another example embodiment, the interface surface 12 may be non-planar, and the upper surface 19 of the diamond mesa may be planar.

[0038] By employing a high thermal conductivity matrix, the peak temperature at the cutting tip of the PCD platform during rock drilling can be reduced. This reduces wear on the PCD platform due to high temperatures during drilling and increases the service life of the cutting elements. The high thermal conductivity matrix can be used in conjunction with leached (TSP) or non-leached polycrystalline diamond cutting layers (i.e., the platform) to improve the thermal performance of the PCD cutting elements.

[0039] In example embodiments, the high thermal conductivity matrix acts as a heat sink during drilling to keep the diamond mesa cool. Currently, the tungsten carbide matrix used in PCD manufacturing has a thermal conductivity of 90 to 110 W / m℃. In example embodiments, the high thermal conductivity matrix has a thermal conductivity greater than 120 W / m℃. In another preferred example embodiment, the high thermal conductivity matrix has a thermal conductivity greater than 130 W / m℃. For example, some embodiments may have a thermal conductivity of 140 W / m℃ or higher. High thermal conductivity allows the matrix to absorb more heat from the diamond mesa during cutting. The thermal conductivity of the matrix can be increased in one or more ways, and thus increase the heat absorbed from the mesa. For example, the thermal conductivity of the matrix can be increased by increasing the grain size of the hard material (e.g., tungsten carbide), reducing the weight percentage of cobalt (Co) used to form the matrix, increasing the length of the carbide matrix, and / or changing the structure and composition of the matrix.

[0040] In some implementations, increasing the thermal conductivity of the matrix by 60 W / m℃ can reduce the peak temperature of the PCD mesa during simulated operations under downhole conditions by up to 49℃. Therefore, for a conventional cutting element with a matrix having a thermal conductivity of 90 W / m℃, this results in a simulated temperature of 859℃ during downhole simulation operations. In contrast, for a current implementation of a cutting element with a matrix having a high thermal conductivity of approximately 151 W / m℃, the improved cutting element implementation results in a simulated temperature of 810℃. According to many implementations, the diamond mesa remains cooler due to the enhanced thermal conductivity of the matrix, and the wear rate of the diamond mesa is reduced during cutting.

[0041] According to various embodiments, the catalyst material in the matrix can permeate into adjacent diamond powders to facilitate the bonding of diamond grains during the HPHT process. The catalyst material can be cobalt (Co) or nickel (Ni), and the matrix used to provide said catalyst material can be a cobalt-containing matrix, such as tungsten carbide-cobalt (WC-Co) or tungsten carbide-cobalt-nickel (WC-CoNi).

[0042] Matrix materials that can be used as infiltration matrices may include metallic materials, ceramic materials, cermet materials, and combinations thereof. Example infiltration matrices may be formed from hard materials (such as carbides such as WC, W₂C, TiC, VC) or superhard materials (such as synthetic diamond, natural diamond, etc.), wherein the hard or superhard material may include a softer binder phase comprising one or more Group VIII materials, such as Co, Ni, Fe, and Cu, and combinations thereof. According to many embodiments, the infiltration matrix may have a material composition designed to ensure its ability to release its binder phase material and infiltrate into the diamond powder during the HPHT process, thereby bonding the diamond mesa to the matrix.

[0043] In an example embodiment, the high thermal conductivity matrix may be formed from WC-Co, comprising a WC hard material with an average particle size greater than about 5 micrometers and in the range of about 6 micrometers to 12 micrometers or about 6 micrometers to 8 micrometers. Based on the total weight of the WC-Co material, the Co content of the matrix may be greater than about 5% by weight and in the range of about 5% by weight to 13% by weight.

[0044] In some embodiments, the high thermal conductivity matrix can be formed from WC-CoNi, comprising a WC hard material with an average particle size greater than about 5 micrometers and ranging from about 6 to 12 micrometers or about 6 to 8 micrometers. Based on the total weight of the WC-CoNi material, the Co content of the matrix can be greater than about 5% by weight and range from about 5% by weight to 10% by weight. Based on the total weight of WC-CoNi, the Ni content of the matrix can be greater than about 1% by weight and range from about 1% by weight to 4% by weight. Reducing the Co content in the matrix can help improve the thermal conductivity of the matrix. That is, reducing the Co content alone or simultaneously adding Ni to the matrix can improve the thermal conductivity of the matrix.

[0045] Various embodiments may include a matrix formed from WC-CoNi, the matrix having an average WC particle size of about 6 micrometers, a Co content of about 9.9 wt%, and a Ni content of about 3.6 wt%. Other embodiments may include a matrix formed from WC-CoNi, the matrix having an average WC particle size of about 6 micrometers, a Co content of about 8.4 wt%, and a Ni content of about 2.6 wt%. In other embodiments, the matrix may be formed from WC-CoNi, the matrix having an average WC particle size of about 6 micrometers, a Co content of about 5 wt%, and a Ni content of about 1 wt%. Various embodiments may include a matrix formed from WC-CoNi, the matrix having an average WC particle size of about 6 micrometers, a Co content of about 7.5 wt%, and a Ni content of about 1.5 wt%. Some embodiments may also include a matrix formed from WC-Co, the matrix having an average particle size between 6 and 8 micrometers, and a Co content of about 13 to 14 wt%.

[0046] Figure 4 An embodiment of a thermally stabilized polycrystalline tool is also shown. According to various embodiments, the material properties of the high-conductivity tungsten carbide matrix, including coarse tungsten carbide (WC) grains (e.g., average grain size greater than 5 micrometers) and low cobalt content, may prevent the sintering of diamond onto the high-conductivity matrix. In such cases, if... Figure 4 As shown, the diamond mesa 18 can be sintered onto a substrate wafer or transition layer 20 having a first thermal conductivity. The substrate wafer can then be bonded to a substrate extension 24 having a second thermal conductivity, which is higher than the first thermal conductivity. As described herein, the substrate extension 24 can have a higher thermal conductivity. In one example embodiment, the substrate wafer can have a thermal conductivity of 90 W / m °C, and the substrate extension can have a thermal conductivity of 151 W / m °C or greater than 120 W / m °C.

[0047] The thermal conductivity of the substrate wafer 20 can be selected to provide sufficient thermal gain while allowing diamond mesa to be sintered thereon. For example, the substrate wafer 20 and the substrate extension 24 together may define a substrate. In some embodiments, the substrate wafer 20 may have a length not exceeding 50% of the total length of the substrate. The thickness of the substrate wafer 20 may be between 15% and 50% of the total thickness of the substrate (e.g., the substrate wafer 20 and the substrate extension 24). For example, the substrate wafer 20 may be 3 mm thick, and the substrate extension 24 may be between 7 mm and 17 mm. In some embodiments, the substrate wafer 20 may be between 20% and 30% of the total thickness of the substrate.

[0048] In several embodiments, the substrate wafer 20 may have a different composition and / or average hard material grain size than the substrate extension 24. In some embodiments, the substrate wafer 20 may have a higher Co content than the substrate extension 24. For example, the substrate wafer 20 may have more than 10% Co, more than 11% Co, more than 12% Co, or more than 13% Co, and the substrate extension 24 may have less than 10% Co, less than 9% Co, less than 8% Co, or less than 7% Co. Alternatively, the substrate wafer 20 may have less Ni than the substrate extension 24. For example, in some embodiments, the substrate wafer 20 may have 13% Co and about 0% Ni, and the substrate extension 24 may have between 5% and 7% Co and between 1% and 2% Ni. Furthermore, the substrate wafer 20 may have an average WC grain size of less than 5 micrometers, such as about 3 micrometers, and the substrate extension 24 may have an average WC grain size of more than 5 micrometers, such as about 6 micrometers. Therefore, the composition of the entire substrate and / or the average WC particle size can be configured to increase thermal conductivity relative to the substrate wafer 20 through the substrate extension 24.

[0049] In some embodiments, the substrate wafer 20 may be bonded to the substrate extension 24 via a soldering material. In some embodiments, an impregnating agent may be placed between the substrate wafer 20 and the substrate extension 24 prior to the HPHT process to facilitate bonding between the substrate wafer 20 and the substrate extension 24. The high thermal conductivity substrate 10 may have multiple axial portions with different thermal conductivities. For example, the substrate wafer 20 may be a first axial portion having a first thermal conductivity that is less than that of a second axial portion having a second thermal conductivity (e.g., the substrate extension 24). Furthermore, the bonding material between the first and second axial portions may have a third thermal conductivity that is between the first and second thermal conductivity.

[0050] According to various embodiments, the first axial portion and the second axial portion may have different thermal conductivities based on the percentage of cobalt. For example, in some embodiments, the cobalt by weight in the first axial portion may be higher or more than the cobalt by weight in the second axial portion or any other portion thereof. Additionally, some embodiments may have different thermal conductivities based on the total length of the different portions. For example, in some embodiments, the first axial portion and the second axial portion may have different lengths. In some embodiments, the first axial portion may be 50% or less of the length of the matrix. Therefore, it is understood that the thermal conductivities of the different axial portions may differ, wherein the thermal conductivity of the first axial portion may be lower than that of the second axial portion. Furthermore, in many embodiments, the particle size of the different axial portions may vary in combination with any of the embodiments disclosed herein. For example, the hard material particle size of the second axial portion may be larger than the average hard material particle size of the first axial portion.

[0051] like Figure 3A As shown in the example embodiments, the substrate length 25 (measured from the bottom 23 of the substrate to the farthest point of the interface surface 12) can be 70% or slightly more than 70% of the total cutting element length 27 (measured from the bottom 23 of the substrate / cutting element to the farthest point of the upper surface 19 of the diamond table). In various embodiments, the substrate may have a length of at least 0.5 inches (12.7 mm) and / or a length greater than 70% of the total length of the cutting element. In several embodiments, the substrate may have a length equal to or greater than 80% of the total length of the tool.

[0052] In some implementations, it can be demonstrated that using a longer matrix in the steel drill body may be more efficient than conventional cutting tools. In FEA analysis of a standard cutting element with a 0.120-inch (3 mm) thick diamond (i.e., PCD) table and a 0.670-inch (17 mm) long matrix (representing 84.8% of the total length of the cutting element), the simulated maximum cutting temperature at the PCD (i.e., diamond) table was reduced by up to 70°C compared to a cutting element with a 0.120-inch (3 mm) thick diamond table and a 0.390-inch (9.9 mm) long matrix (representing 76.5% of the total length of the cutting element).

[0053] The high thermal conductivity matrix discussed herein can be greater than the thermal conductivity of the drill body material, which forms the recess in which the cutting element is disposed. For example, the high thermal conductivity matrix of the cutting element can be greater than that of steel-bodied drills and matrix-bodied drills. In some embodiments, the high thermal conductivity matrix of the cutting element can be 2, 3, 4, or more times the thermal conductivity of the drill body material. Therefore, increasing the length of the matrix increases the heat absorbed from the diamond mesa. Furthermore, increasing the length of the matrix while simultaneously reducing the Co content to less than 10% (by weight of the matrix), increasing the average WC grain size to between 6 and 8 micrometers, or increasing the Ni percentage (by weight of the matrix) can further increase the heat absorbed from the diamond mesa into the matrix, thereby improving the thermal conductivity of the tool and extending its service life.

[0054] In various implementations, the cutting element can be mounted on the blade 28 of the scraper drill body, such as... Figure 5 As shown. Each of these cutting elements may have a base length, a PCD platform thickness, and a total cutting element length. In some embodiments, cutting elements that may be subjected to higher temperatures during drilling may be designed with a longer base having higher thermal conductivity, as described herein, such that the base length may be at least 0.500 inches (12.7 mm) and may be at least 80% of the total length of the cutting element.

[0055] like Figure 2 As shown, some scraper bits may often have two rows of cutting elements 52, 54 mounted on each insert of the scraper bit to address wear of the diamond platform of the cutting elements that may be caused by the high temperatures during drilling. According to various embodiments, as disclosed herein, the cutting elements can be used in a single row of cutting elements on each insert, such as... Figure 5 As shown. In many embodiments, the cutting tool exhibits improved wear resistance at high temperatures during drilling, thus allowing the use of only a single row. In other words, fewer cutting elements with a high thermal conductivity matrix can be arranged on the drill bit compared to a similar drill bit with two rows of cutting elements but without a high thermal conductivity matrix, without reducing the drill bit's effectiveness.

[0056] Although relative terms such as “outer,” “inner,” “upper,” “lower,” “below,” “above,” and similar terms may be used herein to describe the spatial relationship between one element and another, it is understood that these terms are intended to cover the various orientations of the various elements and components of the invention beyond those depicted in the figures. Furthermore, as used herein, when a component is referred to as being “on” another component, it may be located directly on the other component, or there may be components between them. Additionally, when referring to components, the terms “first,” “second,” and “third” are merely labels used to distinguish such components and are not generic names for such components. For example, a component described as a “first” component in the specification may be referred to as a “second” component in the claims.

[0057] Although this disclosure has been provided with specific reference to exemplary embodiments thereof, the exemplary embodiments described herein are not intended to be exhaustive or to limit the scope of the invention to the exact forms disclosed. Those skilled in the art to which this disclosure pertains will understand that modifications and alterations to the described structures and methods of assembly and operation can be practiced without materially departing from the principles, spirit, and scope of this disclosure, as set forth in the following claims.

Claims

1. A cutting element, comprising: A substrate comprising a rigid material and a binder, the substrate having an interfacial surface, wherein at least a portion of the substrate has a thermal conductivity greater than 130 W / m℃; and Polycrystalline diamond mesa on the interface surface.

2. The cutting element of claim 1, wherein the average particle size of the hard material is greater than 5 micrometers.

3. The cutting element as claimed in claim 2, wherein the substrate has a thermal conductivity of at least 140 W / m℃.

4. The cutting element of claim 1, wherein the base has a length and includes a first axial portion and a second axial portion above the first axial portion, wherein the interface surface is formed on the first axial portion, and wherein the first axial portion has a length not greater than 50% of the length of the base.

5. The cutting element of claim 4, wherein the first axial portion has a lower thermal conductivity than the second axial portion.

6. The cutting element of claim 5, wherein the first axial portion matrix contains more cobalt by weight than the second axial portion.

7. The cutting element of claim 1, wherein the substrate length is greater than 12.7 mm, wherein the polycrystalline diamond mesa has a mesa thickness, and the cutting element length of the cutting element is the sum of the substrate length and the mesa thickness, wherein the substrate length is greater than 80% of the cutting element length.

8. The cutting element of claim 1, wherein the binder comprises cobalt and nickel, wherein the cobalt comprises between 5% and 10% by weight of the substrate, and the nickel comprises between 1% and 4% by weight of the substrate.

9. The cutting element of claim 8, wherein the cobalt comprises less than 8% by weight of the matrix, the nickel comprises between 1% and 2% by weight of the matrix, and the average particle size of the hard material is between 6 micrometers and 8 micrometers.

10. A scraper drill bit, comprising: Multiple blades; and Multiple cutting elements are mounted on each blade, and at least one of the cutting elements includes, A substrate comprising a rigid material and a binder, the substrate having an interfacial surface, wherein at least a portion of the substrate has a thermal conductivity greater than 130 W / m℃, and Polycrystalline diamond mesa on the interface surface.

11. The scraper drill bit of claim 10, wherein the average particle size of the hard material is between 6 micrometers and 8 micrometers.

12. The scraper drill bit of claim 11, wherein the matrix of the at least one cutting element has a thermal conductivity of at least 140 W / m℃.

13. The scraper drill bit of claim 10, wherein the base of the at least one cutting element has a length and includes a first axial portion and a second axial portion above the first axial portion, wherein the interface surface is formed on the first axial portion, and wherein the first axial portion has a length not greater than 50% of the length of the base.

14. The scraper drill bit of claim 13, wherein the first axial portion has a lower thermal conductivity than the second axial portion.

15. The scraper bit of claim 14, wherein the second axial portion comprises a CoNi matrix containing between 5% and 7% cobalt and between 1% and 2% nickel.

16. The scraper drill bit of claim 14, wherein the average hard material particle size of the second axial portion is greater than the average hard material particle size of the first axial portion.

17. The scraper drill bit of claim 10, wherein the base length of the at least one cutting element is greater than 12.7 mm, wherein the polycrystalline diamond mesa of the at least one cutting element has a mesa thickness, and the cutting element length of the at least one cutting element is the sum of the base length and the mesa thickness, wherein the base length of the at least one cutting element is greater than 80% of the cutting element length.

18. The scraper drill bit of claim 10, wherein the binder comprises cobalt and nickel, wherein the cobalt comprises between 5% and 10% by weight of the matrix, and the nickel comprises between 1% and 4% by weight of the matrix.

19. The scraper drill bit of claims 18 and 8, wherein the cobalt comprises less than 8% by weight of the matrix, the nickel comprises between 1% and 2% by weight of the matrix, and the average particle size of the hard material is between 6 micrometers and 8 micrometers.

20. The scraper drill bit of claim 10, wherein each blade comprises only a single row of cutting elements.

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