The disclosure relates generally to a cutting tooth and drill bit. The disclosure relates specifically to a polycrystalline diamond compact cutter for use in the field of drill bits for petroleum exploration and drilling operation.
At present, diamond drill bits are widely used in petroleum exploration and drilling operation. This kind of bit consist of a bit body part and diamond composite sheet cutting tooth, the bit body part is made of sintered tungsten carbide material or is formed by processing a metal material as a substrate, and the diamond composite sheet cutting tooth is brazed to the front end of the cutting face of the blade of the bit. In the drilling process, diamond composite sheet cuts rock and withstands great impact from the rock at the same time. They are prone to impact damage when drilling into a high gravel content formation or a hard formation, resulting in damage to the cutting faces. On the other hand, when drilling in shale, mudstone and other formations, the debris produced by cutting through diamond composite sheet can easily form a long strip shape debris. Due to the large size of this kind of debris, it will easily attach to the blades and body part of the bit to form balling, such that the cutting work faces of the blades of the bit are wrapped and unable to continue working, eventually leading to decrease of mechanical speed, no drill footage and other issues. The day rate is very high during the process of drilling. The replacement of the drill bit in virtue of the poor impact resistance or as a result of the decreased mechanical speed owning to the balling will bring high economic costs, so it has become a top priority to effectively improve the ability of impact resistance and the balling resistance of the drill bit.
Downhole drilling applications for oil and gas are challenging due to high temperature, high pressure, impact, and abrasion. Both the drill bit and polycrystalline diamond compact (PDC) cutter lifespan and performance are decreased by heat, stresses around individual cutters, and abrasion. It would be advantageous to have a PDC cutter with improved geometry for cooling and cutting evacuation and efficiency.
An embodiment of the disclosure is a cutting tooth comprising a cylindrical body, wherein the surface of the end portion of the cylindrical body is provided with three cutting ridges, wherein the inner end of each of the cutting ridges extends to a triangle at the vertex of a Reuleaux triangle at the end portion of the cylindrical body, wherein the outer end of each of the cutting ridges extend to the outer edge of the surface of the end portion of the cylindrical body, wherein the surfaces of the end portion of the cylindrical body on each side of each of the cutting ridges are cutting bevels; and three cutting points, each located at the triangle at the vertex of a Reuleaux triangle at the end portion of the cylindrical body.
In an embodiment, the cylindrical body comprises a base formed of tungsten carbide material and a polycrystalline diamond layer connected to the top of the base, the cutting ridges are located on the upper surface of the polycrystalline diamond layer. In an embodiment, the angle between the cutting ridges is 80°-140°. In an embodiment, the length of each of the cutting ridges is the same. In an embodiment, the cutting tooth further comprises a chamfered surface at the outer end of each of the cutting ridges. In an embodiment, the bevel size of the chamfered surface is between 0.014 and 0.022 inches. In an embodiment, the radius from the center of the cutting tooth to where the triangle meets the Reuleaux triangle is 0.173 inches. In an embodiment, the radius from the center of the cutting tooth to where the outermost vertex of the triangle is from about 0.150 to 0.450 inches. In an embodiment, the height of a backplane from the center of the Reuleaux triangle to the inner edge of the chamfered surface from 0.046-0.054 inches. In an embodiment, a cone angle from the inner edge of the chamfered surface to the Reuleaux triangle center is 2.50°-10.00°.
An embodiment of the disclosure is a diamond drill bit, comprising: a drill bit body equipped with an axial through water channel therein, a connection portion is formed at one end of the drill bit body, the other end of the drill bit body is provided with a plurality of water holes which can communicate with the water channel; a plurality of blades connected to the other end of the drill bit body in the circumferential direction, one side of each of the blade equipped with a plurality of cutting teeth side by side, the plurality of cutting teeth can comprise cutting teeth from the embodiments above.
The object of the present disclosure is to provide a convex ridge type non-planar cutting tooth having great impact resistance and balling resistance. The convex ridge type non-planar cutting teeth are mounted on a drill bit to increase the mechanical speed and footage of the drill bit.
Another object of the present disclosure is to provide a diamond drill bit, convex ridge type non-planar cutting teeth are arranged on the diamond drill bit, which can effectively improve the impact resistance and balling resistance of the drill bit, thus to increase the mechanical speed and footage of the drill bit.
The above objects of the present disclosure can be achieved by employing the following technical solutions:
The present disclosure provides a convex ridge type non-planar cutting tooth comprising a cylindrical body, the surface of the end portion of the cylindrical body is provided with a main cutting convex ridge and two non-cutting convex ridges, the inner end of the main cutting convex ridge and the inner ends of the two non-cutting convex ridges converge at the surface of the end portion of the cylindrical body, the outer end of the main cutting convex ridge and the outer ends of the two non-cutting convex ridges extend to the outer edge of the surface of the end portion of the cylindrical body, the surfaces of the end portion of the cylindrical body on both sides of the main cutting convex ridge are cutting bevels.
In a preferred embodiment, the surface of the end portion of the cylindrical body between the two non-cutting convex ridges is a back bevel.
In a preferred embodiment, the surface of the end portion of the cylindrical body between the two non-cutting convex ridges is a back plane.
In a preferred embodiment, the cylindrical body comprises a base formed of tungsten carbide material and a polycrystalline diamond layer connected to the top of the base, the main cutting convex ridge and two non-cutting convex ridges are located on the upper surface of the polycrystalline diamond layer.
In an embodiment, the cylindrical body comprises a base including but not limited to high speed steel, carbon steel, titanium, cobalt, or tungsten carbide. In an embodiment, the layer at the top of the base is comprised of a diamond layer including but not limited to metal-bonded diamond, resin-bonded diamond, plated diamond, ceramic-bonded diamond, polycrystalline diamond, polycrystalline diamond composite, or high temperature brazed diamond tools.
In a preferred embodiment, the angle between the two cutting bevels is 150° to 175°.
In an embodiment, the angle between the two cutting bevels is 90° to 175°.
In a preferred embodiment, the length of the main cutting convex ridge is equal to that of the non-cutting convex ridges.
In an embodiment, the length of the main cutting convex ridge is not equal to that of the non-cutting convex ridges.
In a preferred embodiment, the length of the main cutting convex ridge is larger than that of the non-cutting convex ridges.
In an embodiment, the length of the main cutting convex ridge is smaller than that of the non-cutting convex ridges.
In a preferred embodiment, the length of the main cutting convex ridge is ½-⅔ times of the diameter of the cylindrical body.
The present disclosure also provides a diamond drill bit, comprising:
a drill bit body equipped with an axial through water channel therein, a connection portion is formed at one end of the drill bit body, the other end of the drill bit body is provided with a plurality of water holes which can communicate with the water channel;
a plurality of blades connected to the other end of the drill bit body in the circumferential direction, one side of each of the blade equipped with a plurality of cutting teeth side by side, the plurality of cutting teeth comprise said convex ridge type non-planar cutting teeth.
In a preferred embodiment, the blade has an inner side and outer side surface, a top surface of the blade is connected between the inner side surface and outer side surface. the plurality of the cutting teeth are disposed on the outer edge of the top surface of the blade and near the inner side surface; the top surface of the blade comprises a heart portion, a nose portion, a shoulder portion and a gauge protection portion connected in turn which are extended from the center shaft diameter of the drill bit body to outside, the heart portion is close to the central axis of the drill bit body, the gauge protection portion is located on the side wall of the drill bit body and the cutting teeth are distributed across the heart portion, the nose portion, the shoulder portion and the gauge protection portion of the blade.
In a preferred embodiment, a plurality of blades are further provided with a plurality of secondary cutting teeth. The secondary cutting teeth are arranged in the back row of the cutting teeth along the rotary cutting direction of the drill bit body, the plurality of secondary cutting teeth include the convex ridge type non-planar cutting tooth.
In a preferred embodiment, the convex ridge type non-planar cutting teeth are arranged on the heart portion of the blade.
In a preferred embodiment, the convex ridge type non-planar cutting teeth are arranged on the shoulder portion of the blade.
In a preferred embodiment, the convex ridge type non-planar cutting teeth are arranged on the nose portion of the blade.
In a preferred embodiment, the convex ridge type non-planar cutting teeth are arranged on the gauge protection portion of the blade.
In a preferred embodiment, the convex ridge type non-planar cutting teeth are arranged on more than one portion of the blade.
In a preferred embodiment, the convex ridge type non-planar cutting teeth are arranged on the heart, shoulder, nose, and gauge portions of the blade.
In a preferred embodiment, the convex ridge type non-planar cutting teeth and the cutting teeth are arranged in a staggered arrangement along the axial direction of the drill bit body.
In a preferred embodiment, the convex ridge type non-planar cutting teeth and the cutting teeth are arranged in an aligned arrangement along the axial direction of the drill bit body.
In a preferred embodiment, the non-planar cutting tooth comprises a base, a table connected to a top of the base. a concave shaped surface on the center portion of a top surface of the table; three cutting ridges with each extending from a vertex of the concave shaped surface to an outer edge of the top surface; three cutting bevels with each locating between two cutting ridges of the three cutting ridges; each of the three cutting ridges has a fillet.
The concave shaped surface is a conical depression. The outer perimeter of the conical depression is a Reuleaux triangle or a space curve through an intersection of a cone and a tetrahedron. The concave shaped surface is any one of an inverted tetrahedron, a tetrahedron frustum. a curved cone or a dome.
The characteristics and advantages of the convex ridge type non-planar cutting teeth and the diamond drill bit according to the present disclosure are:
The convex ridge type non-planar cutting tooth of the present disclosure changes the traditional plane cylindrical cutting tooth design into a convex ridge type non-planar cutting tooth, which can greatly improve the ability of positive direction impact resistance of the cutting tooth; In addition, the main cutting convex ridge which is located at the outer end of the edge of the upper surface of the polycrystalline diamond layer acts as a cutting point. In the process of cutting, the debris can be automatically formed into two branches from the cutting point, and can be squeezed out from the cutting bevels on both sides of the main cutting convex ridge, such that the debris is prevented from sliding to the body part of the blade along the upper surface of the polycrystalline diamond layer and forming balling, thus greatly improving the ability of balling resistance of the cutting tooth.
When drilling into a formation that is easy to form balling, the diamond drill bit of the present disclosure arranges the convex ridge type non-planar cutting teeth in the heart portion, such that the size of the debris produced by the cutting teeth in the heart portion can be reduced, and the debris can be easier to be carried out of bottom of a well by drilling fluid, thus to reduce the risk of bit balling. In addition, when drilling into a gravel content formation and the like, the convex ridge type non-planar cutting teeth are arranged on the shoulder portion, therefore to improve the ability of impact resistance of the drill bit. Furthermore, when drilling into a high impact formation, the convex ridge type non-planar cutting teeth are arranged on the shoulder portion and the outer side of the nose portion, thus to improve the ability of impact resistance of the cutting teeth in these areas, and to improve the life of drill bit. Of course, the convex ridge type non-planar cutting teeth may also be arranged in the position of the secondary cutting teeth of the blade of the diamond drill bit to accommodate the needs of drilling into different formations.
The foregoing has outlined rather broadly the features of the present disclosure in order that the detailed description that follows may be better understood. Additional features and advantages of the disclosure will be described hereinafter, which form the subject of the claims.
In order that the manner in which the above-recited and other enhancements and objects of the disclosure are obtained, a more particular description of the disclosure briefly described above will be rendered by reference to specific embodiments thereof which are illustrated in the appended drawings. Understanding that these drawings depict only typical embodiments of the disclosure and are therefore not to be considered limiting of its scope, the disclosure will be described with additional specificity and detail through the use of the accompanying drawings in which:
The particulars shown herein are by way of example and for purposes of illustrative discussion of the preferred embodiments of the present disclosure only and are presented in the cause of providing what is believed to be the most useful and readily understood description of the principles and conceptual aspects of various embodiments of the disclosure. In this regard, no attempt is made to show structural details of the disclosure in more detail than is necessary for the fundamental understanding of the disclosure, the description taken with the drawings making apparent to those skilled in the art how the several forms of the disclosure may be embodied in practice.
Referring to
Specifically, the cylindrical body 1 comprises a base 15 formed of tungsten carbide material and a polycrystalline diamond layer 16 connected to the top of the base, the main cutting convex ridge 11 and two non-cutting convex ridges 12 are located on the upper surface of the polycrystalline diamond layer 16, and a plurality of welding positioning holes 151 are arranged on the lower surface of the base 15.
Material properties of polycrystalline diamond are determined mainly by the selected particles scale during sintering, polycrystalline diamond having an average particle dimension between 1 μm to 50 μm after sintering. The smaller the particle size, the wear resistance of the sintered polycrystalline diamond is higher, but the corresponding impact resistance is lower. In the present disclosure, through testing the wear resistance of the convex ridge type non-planar cutting tooth by vertical lathe test, it is found that the wear of the convex ridge type non-planar cutting tooth is relatively lower than that of the conventional plane tooth. So, smaller particle size should be used for sintering. The average particle dimension of the sintered polycrystalline diamond layer 16 is from 1 μm to 25 μm according to the present disclosure.
Further, the inner end of the main cutting convex ridge 11 and the inner ends of the two non-cutting convex ridges 12 converge at the middle of the upper surface of the polycrystalline diamond layer 16, the outer end of the main cutting convex ridge 11 and the outer ends of the two non-cutting convex ridges 12 extend to the outer edge 13 of the upper surface of the polycrystalline diamond layer 16. Chamfered surfaces 18 are present. Viewed from the top of the polycrystalline diamond layer 16, the main cutting convex ridge 11 and the two non-cutting convex ridges 12 form a substantially “Y” type pattern, and the main cutting convex ridge 11 and the two noncutting convex ridges 12 divide the upper surface of the polycrystalline diamond layer 16 into three surfaces. The upper surface of the polycrystalline diamond layer 16 located on both sides of the main cutting ridge 11 are cutting bevels 14, the cutting bevels 14 extend along an axial direction from the center of the cylindrical body 1 outwardly and downwardly. The upper surface of the polycrystalline diamond layer 16 between the two non-cutting convex ridges 12 (i.e., the surface of the end portion of the cylindrical body 1) is a back surface 17. That is, the cutting bevels 14 are divided by the back surface 17 on the side away from the outer end of the main cutting convex ridge 11, and the cutting bevels 14 do not meet at the far end.
When cutting shale, mudstone and other formations with the convex ridge type nonplanar cutting tooth, the two cutting bevels 14 separate the strip shape debris cut by conventional planar diamond composite sheet into two smaller size debris. Chamfered surfaces 18 are present. The portions of the two cutting bevels 14 which are away from the cutting point 131 are divided by the backplane 17, and do not directly converge at the surface of the blade of the drill bit, so the debris will not be attached directly to the blade of the drill bit in more cases, but will be dispersed along the two cutting bevels 14 in drilling fluid and be carried out of the bottom of a well, which will greatly reduce the balling produced by debris attached to the blade of the drill bit and wrapping the cutting work face, thereby improving the life of the drill bit, increasing mechanical speed and drill footage.
After cutting rock with the convex ridge type non-planar cutting teeth and conventional planar cutting teeth in the same test parameters, filtering analysis of the degree of coarse of debris through the filter screen, it can be seen that the ratio of the debris passing through the #40 filter screen (fine debris) to debris produced by the convex ridge type non-planar cutting teeth is higher than that of the debris passing through the #40 filter screen to debris produced by the conventional planar cutting teeth, and that the ratio of the debris not passing through the #40 filter screen (coarse debris) to debris produced by the convex ridge type non-planar cutting teeth is lower than that of the debris not passing through the #40 filter screen to debris produced by the conventional planar cutting teeth, which shows that the convex ridge type non-planar cutting teeth can produce finer debris under the same cutting conditions, thereby improving the ability to carry the debris out of the bottom of a well by drilling fluid, and reducing the risk of forming bit balling.
Polycrystalline diamond layer 16 of the present disclosure is designed to adopt a non-planar convex ridge, which has higher impact resistance than conventional planar diamond composite sheet. By performing benchmarking experiments using the impact fatigue testing machine, performance figures of impact resistance of both can be obtained and compared. The composite layer of a test sample is fixed on the flywheel of the impact fatigue testing machine through a special clamp, a motor drives the flywheel to rotate. In every revolution to the position of nine o'clock, the test sample impacts a striking block fixed to the left side and supported by a spring, rotating the flywheel for repeated impact until the test sample is destroyed. The impact fatigue property of the sample was evaluated by the number of recorded impacts before the failure. If damage occurs in the process of impact test, the test should be stopped immediately; and if the impact is up to 12,000 times and the sample is not damaged yet, the test should also be stopped. (In the actual test, because there are time lag effects in counter and the flywheel, the actual number of the impact of samples may slightly above 12,000 after the stop). After four cutting teeth which are sintered with different grain size diamond are machined into convex ridge type non-planar cutting teeth, they withstand impact fatigue test and are compared with planar cutting teeth with the same size sintered diamond. The experimental results show that the ability of positive direction impact resistance of convex ridge type non-planar cutting teeth is much higher than that of conventional planar cutting teeth.
In one embodiment of the present disclosure, as shown in
In another embodiment of the present disclosure, referring back to
In different applications, according to cost demand, the number of slopes of the upper surface the polycrystalline diamond layer 16 of the present disclosure is designed to two or three, in order to optimize the manufacturing cost.
In an embodiment, referring to
In an embodiment, the main cutting ridge 11 has a length of ½ to ⅔ times of the diameter of the cylindrical body 1, the benefits of this kind of design are to improve the ability of impact and balling resistance of the convex ridge type non-planar cutting tooth.
In a particular embodiment, shown in
The manufacturing process of the convex ridge type non-planar cutting tooth of the present disclosure is as follows:
In the first place, conventional plane type diamond composite sheet is fabricated by high temperature and high pressure sintering and then is processed by centerless grinding, after the outer diameter achieves the design requirements, polishing the top layer of the diamond composite sheet to conventional plane type on diamond millstone, and then the required top slope is machined on the surface of the diamond composite layer by laser cutting, The process need not one-time forming of the required diamond slope during sintering.
EDM is a kind of method to process the size of materials which employs the corrosion phenomena produced by spark discharge. In a low voltage range, EDM performs spark discharge in liquid medium. EDM is a self-excited discharge, which is characterized as follows: before discharge, there is a higher voltage between two electrodes used in spark discharge, when the two electrodes are close, the dielectric between them is broken down, spark discharge will be generated. In the process of the break down, the resistance between the two electrodes abruptly decreases, the voltage between the two electrodes is thus lowered abruptly. Spark channel must be promptly extinguished after maintaining a fleeting time, in order to maintain a “cold pole” feature of the spark discharge, that is, there's not enough time to transmit the thermal energy produced by the channel energy to the depth of the electrode. The channel energy can corrode the electrode partially. When processing diamond composite sheet with EDM, since the residual catalyst metal cobalt produced in the process sintering diamond composite sheet having conductivity, the diamond composite sheet can be used as electrodes in the EDM, and thus can be machined by EDM.
EDM can avoid the error caused by the inability to accurately control the diamond shrinkage during sintering process. EDM technology can effectively control the machining accuracy, and reduce the damage to the diamond layer during the machining process. Convex ridge type tooth formed by electric spark machining have characteristics of high processing precision, low cost, small damage to the surface of the diamond layer and so on. When processing the convex ridge type non-planar cutting tooth, one can prefabricate plane type diamond composite layer at first, and then perform precision machining through EDM. The whole process cost can be reduced, the machining accuracy is satisfied, and the damage to the surface of the diamond composite layer is minimal There is no need to develop sintering cavity assembly for the diamond composite layer, thus having good flexibility and low-cost.
The convex ridge type non-planar cutting teeth of the present disclosure change the traditional plane cylindrical cutting tooth design into convex ridge type non-planar cutting tooth, which can greatly improve the ability of positive direction impact resistance of the cutting tooth. In addition, the main cutting convex ridge 11 which is located at the outer end of the edge 13 of the upper surface of the polycrystalline diamond layer 16 acts as a cutting point 131. Chamfered surfaces 18 are present. In the process of cutting, the debris can be automatically formed into two branches from the cutting point 131, and can be squeezed out from the cutting bevels 14 on both sides of the main cutting convex ridge 11, such that the debris is prevented from sliding to the body part of the blade along the upper surface of the polycrystalline diamond layer 16 and forming balling, thus greatly improving the ability of balling resistance of the drill bit.
As shown in
Specifically, the drill bit body 3 is substantially cylindrical, the connection portion 32 has a threaded section and is used to connect to a drill string. The power is transmitted to the diamond drill bit by the drill string. There is the water channel 31 in the middle part of the drill bit body 3, and the water channel 31 communicates with the connection portion 32, the other end of the drill bit body 3 is provided with a plurality of water holes 33 which can communicate with the water channel 31.
A plurality of blades 4 connected to the end of the drill bit body 3 provided with a plurality of water holes 33. In the present disclosure, the blade 4 has an inner side surface 41 and an outer side surface 42, a top surface 43 of the blade is connected between the inner side surface 41 and outer side surface 42. The plurality of the cutting teeth 5 are disposed on the outer edge of the top surface 43 of the blade and near the inner side surface 42; furthermore, the top surface 43 of the blade comprises a heart portion 431, a nose portion 432, a shoulder portion 433 and a gauge protection portion 434 connected in turn which are extended from the center shaft diameter of the drill bit body 3 to outside, the heart portion 431 is close to the central axis of the drill bit body 3, the gauge protection portion 434 is located on the side wall of the drill bit body 3 and the cutting teeth 5 are distributed across the heart portion 431, the nose portion 432, the shoulder portion 433 and the gauge protection portion 434 of the blade 4.
Wherein, in one embodiment, the convex ridge type non-planar cutting teeth 10 and the cutting teeth 5 are arranged in a staggered arrangement along the axial direction of the drill bit body 3, that is, among the plurality of the cutting teeth 10 disposed on the outer edge of the top surface 43 of the blade and near the inner side surface 42, a conventional traditional plane cutting teeth 5 is arranged between the two convex ridge type non-planar cutting teeth 10.
If the balling is formed during drilling, it is usually that the debris begins to gather to the position of the heart portion 431 of the drill bit, because in this region, due to the limited space of the blades 4 and area which mud sprayed from the water holes 33 flows through being small, the region has the minimum ability to discharge debris. Therefore, in the application of easy balling formation, convex ridge cutting tooth can be arrange at the position of the heart portion 431 of the drill bit to reduce the possibility of forming bit balling.
As shown in
As shown in
Of course, in other embodiments, the cutting teeth on the diamond drill bit can also all be convex ridge type non-planar cutting teeth. This kind of drill bit can be used in the formation of readily severe balling. The convex ridge type non-planar cutting teeth at the heart portion can improve the property of anti-bit balling. The cost of the drill bit employing all convex ridge type non-planar cutting teeth is higher than the diamond drill bit in
In addition, the tooth at the shoulder portion usually bears the maximum cutting power during drilling. When drilling into high impact formation, because the teeth located at the shoulder portion have a higher line speed, they are easy to bear the impact force from the circumferential direction which leads to the collapse of the teeth. When drilling into this kind of formation, the convex ridge type non-planar cutting teeth are arranged on the shoulder portion and the outer side of the nose portion, thus to improve the ability of impact resistance of the cutting teeth in these areas, and to improve the life of the drill bit.
In another embodiment of the present disclosure, a plurality of blades 4 are further provided with a plurality of secondary cutting teeth 45.
In the diamond drill bit of the present disclosure, the convex ridge type non-planar cutting teeth are arranged in the heart portion 431, nose portion 432 and shoulder portion 433 of the blade 4 of the drill bit, to accommodate the needs of different formation drilling.
Description of its Functionality when Drilling Hard and Brittle Rock.
The convex cutter induces a stress concentration point when the bit drills into a heterogeneous formation and engages on the harder rock. Other than the regular flat cutter shears off the rock, the rock creates a crack initiation point and the contacting ridge. The rock breaks through its cleavage plane through each side and forms two cuttings along the cleavage plane as shown in
Description of Drilling into Sandstone and Mudstone and the Indicator for Bit Work Life
When drilling into sandstone and mudstone, the convex ridge cutter creates a deformation of the rock.
Description of Drilling into Sandstone and Mudstone and the Efficiency Improvement
As shown in
Downhole drilling applications for oil and gas are challenging due to the high temperature, high pressure, impact and abrasion. Both the drill bit and PDC cutter lifespan and performance are decreased by heat, stresses around individual cutters and abrasion. Placing a cone in the center of the cutter, creates a new geometry which will increase the lifespan of individual PDC cutters by lowering the internal temperature and displacing the heat to the periphery. Additionally, this design will also improve drilling by reducing stresses on the edge of the cutter and cleaning the cuttings more efficiently. In an embodiment, features of the cutter include heat dissipation from the tip of the cutter, cutting evacuation improvement, and more sharp edges reduce stresses in the diamond table.
Referring to
Specifically, the cylindrical body 1201 comprises a base 1215 formed of tungsten carbide material and a polycrystalline diamond layer 1216 connected to the top of the base. The cutting ridges 1212 are located on the upper surface of the polycrystalline diamond layer 1216.
Material properties of polycrystalline diamond are determined mainly by the selected particles scale during sintering, polycrystalline diamond having an average particle dimension between 1 μm to 50 μm after sintering. The smaller the particle size, the wear resistance of the sintered polycrystalline diamond is higher, but the corresponding impact resistance is lower. In an embodiment, the average particle dimension of the sintered polycrystalline diamond layer 1216 is from 1 μm to 25 μm.
The inner ends of the cutting ridges 1212 extend to triangles 1220 at the vertices of a Reuleaux triangle at the middle of the upper surface of the polycrystalline diamond layer 1216. The outer end of the cutting ridges 1212 extend to the outer edge 1213 of the upper surface of the polycrystalline diamond layer 1216. Chamfered surfaces 1218 are present. Viewed from the top of the polycrystalline diamond layer 1216, the cutting ridges 1212 form a Reuleaux triangle with triangles at its vertices. The upper surface of the polycrystalline diamond layer 1216 located on both sides of the cutting ridges 1212 are cutting bevels 1214, the cutting bevels 1214 extend along an axial direction from the triangles 1220 at the vertices of the Reuleaux triangle on the upper surface of the polycrystalline diamond layer 1216 outwardly and downwardly. In an embodiment, the triangle can be any circular triangle. The upper surface of the polycrystalline diamond layer 1216 between the cutting ridges 1212 (i.e., the surface of the end portion of the cylindrical body 1201) is cutting bevel 1214.
In an embodiment, referring to
In an embodiment, the cutting ridge 1212 has a length of ¼ to 1/10 times the diameter of the cylindrical body 1201.
In an embodiment, shown in
In an embodiment, the radius from the location where the triangle 1220 meets the Reuleaux triangle is 0.173 inches. In an embodiment, the radius from the location of the outermost vertex of the triangle 1220 is 0.200 inches.
The top surface 1303 of the table 1306 is provided with three cutting ridges 1312, the inner ends of the three cutting ridges 1312 respectively extend to vertices of a triangle 1325 at the center portion of the top surface 1303. The outer end of the cutting ridges 1312 extend to the outer edge of the top surface 1303. The surfaces of the top surface 1303 on both sides of the cutting ridges 1312 are cutting bevels 1314. The cutting bevels 1314 extend along an axial direction from the triangle 1325 to outer edge of the top surface 1303 downwardly. Chamfered surface 1313 is provided between the top surface 1303 and lateral surface of the top. Although the cutting tooth in example 7 is similar to the cutting tooth in example 6 and share most of the same features of the cutting tooth in example 6, cutting tooth in example 7 has different cutting ridges and different interface between the base and the table.
Referring to
A conventional interface between the base and the table is a plane. The interface 1309 between the base 1305 and the table 1306 of the present disclosure is a curved surface. Particularly, the table 1306 has three tips 1308 projected from the table to engage corresponding pits on the base 1305. The three tips 1308 are right below the three cutting ridges 1312 respectively to improve cutting ridge impact resistance and mitigate cutter spalling.
As will be recognized by those skilled in the art, there are other PDC cutting tooth designs in accordance with the features of this disclosure.
The cutting teeth in
In
In
In
In
The concave shape surface in
In an embodiment, the middle portion of the diamond table is a depression. In an embodiment, the outer perimeter is not on a plane (it is a space curve through the intersection of a cone and a tetrahedron, not necessary a Reuleaux). In an embodiment, the perimeter can be a triangle, a space curve intersects by an inverted cone and a tetrahedron or any other space curve. In an embodiment, the depression can be an inverted tetrahedron, tetrahedron frustum, cone, curved cone, dome, or any other concave shape.
The above described are only several embodiments of the present disclosure. Based on the contents disclosed in the present disclosure, those skilled in the art may make various modifications or variations without departing from the spirit and scope of the disclosure.
Number | Date | Country | Kind |
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201510533014.4 | Aug 2015 | CN | national |
This application is a continuation-in-part of U.S. patent application Ser. No. 16/792,789, filed Feb. 17, 2020; which is a continuation of U.S. patent application Ser. No. 16/155,359, filed Oct. 9, 2018 which issued as U.S. Pat. No. 10,563,464 on Feb. 18, 2020; which is a continuation-in-part of U.S. patent application Ser. No. 15/248,501, filed Aug. 26, 2016, now U.S. Pat. No. 10,125,552; which claims priority to Patent Application CN2015105330144, filed on Aug. 27, 2015, all of which are specifically incorporated by reference in their entirety herein.
Number | Date | Country | |
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Parent | 16155359 | Oct 2018 | US |
Child | 16792789 | US |
Number | Date | Country | |
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Parent | 16792789 | Feb 2020 | US |
Child | 16927569 | US | |
Parent | 15248501 | Aug 2016 | US |
Child | 16155359 | US |