Earth-boring tools with adjacent cutting elements having enhanced hydraulic forces and methods of forming

Abstract

A tool for drilling a borehole in an earth formation. The tool includes a body, an insert having a rotating front face extending from the tool body, a cutting element at least partially secured within a cutting element pocket, and a linear or rounded transition surface between the cutting element pocket and the rotating front face of the insert. The rounded transition surface has a radius of curvature between about 3 millimeters and 150 millimeters. The disclosure also includes a method of manufacturing a downhole earth boring tool, the method including providing a tool body and an insert including a rotating front face extending from the tool body; forming a cutting element pocket in the insert adjacent the rotating front face of the insert; forming a linear or rounded transition surface between the cutting element pocket and the rotating front face of the insert, the rounded transition surface having a radius of curvature between about 3 millimeters and 150 millimeters; and at least partially securing a cutting element within the cutting element pocket.

Description

[0001] Priority Statement

[0002] This application claims the benefit of U.S. Patent Application Serial No. 16 / 823,131, filed on March 18, 2020, for the subject of “EARTH BORING TOOLS WITH ENHANCEDHYDRAULICS ADJACENT CUTTING ELEMENTS AND METHODS OF FORMING”. Technical Field

[0003] The embodiments of this disclosure generally relate to drilling operations. Specifically, embodiments of this disclosure relate to soil drilling tools with enhanced hydraulic performance adjacent to the cutting elements and methods for forming such soil drilling tools. Background Technology

[0004] Wellbores are formed in underground formations for various purposes, including, for example, extracting oil and gas and geothermal energy from underground formations. Drilling tools, such as rotary drill bits, can be used to form wellbores in underground formations. The rotary drill bit is rotated and advanced into the underground formation. As the rotary drill bit rotates, its cutting teeth or abrasive structures cut, crush, shear, and / or grind away the formation material to form a wellbore.

[0005] A drilling rotary bit is coupled directly or indirectly to an end of what is known in the art as a "drill string," which comprises a series of elongated tubular segments connected end-to-end, extending from the surface above the subsurface formation into the wellbore. Various tools and components, including the drill bit, can be joined together at the distal end of the drill string, located at the bottom of the wellbore. This assembly of tools and components is known in the art as a "bottomhole assembly" (BHA).

[0006] A drilling rig can be rotated within the wellbore by rotating the drill string from the formation surface; or by connecting the drill bit to a downhole motor, which is attached to the drill string and positioned near the bottom of the wellbore. The downhole motor may include, for example, a hydraulic Movano motor with a shaft on which the drilling rig is mounted. Rotation of the drill bit is caused by pumping fluid (e.g., drilling mud or drilling fluid) downwards from the formation surface through the center of the drill string, through the hydraulic motor, and out of a nozzle in the drill bit, and by returning the fluid upwards to the formation surface through an annular space between the outer surface of the drill string and the exposed formation surface within the wellbore. The downhole motor can operate with or without drill string rotation.

[0007] Different types of rotary drilling bits are known in the art, including fixed-cutting-tooth bits, rolling-cutting-tooth bits, and hybrid bits (which may include, for example, both fixed-cutting-tooth and rolling-cutting-tooth bits). Unlike roller cone bits, fixed-cutting-tooth bits have no moving parts. There are generally two types of fixed-cutting-tooth bits: matrix bits and steel-body bits. Matrix bits are typically made of tungsten carbide, which is more corrosion-resistant than steel. Matrix bits are generally preferred when using drilling mud with high solids content. Steel-body bits are generally preferred for soft, non-abrasive formations and large borehole diameters. Steel-body bits are also better able to withstand impact loads than matrix bits.

[0008] Steel-bodied drills typically include various features, including but not limited to cutting inserts, nozzle inserts, and cutting element recesses. Steel-bodied drills are generally formed in machining processes using computer numerical control (“CNC”) lathes and milling machines. In this process, a steel bar can be rotated to form the general outline of the drill. The borehole and cutting element recesses can be formed by drilling operations. The cutting inserts and tips can be formed by milling.

[0009] Figure 1 A prior art fixed-cutting-tooth rotary drill bit 100 is shown for use in conjunction with a drilling system. The prior art drill bit 100 includes a drill bit body 102, which may further include a plurality of cutting blades 104 separated by a chip flute 106. Each of the plurality of cutting blades includes a front rotating surface 118, a rear rotating surface 122, and a blade face 120 located between the front rotating surface 118 and the rear rotating surface 122. The drill bit body 102 may include an internal fluid passage extending between the plurality of cutting blades 104 and a longitudinal bore, thereby extending through the shank to the drill string. The drill bit body 102 may further include a nozzle 108 in the chip flute 106 connected to the internal fluid passage. In some embodiments, the drill bit body 102 may include a gauge-protecting wear plug 110 and a wear-resistant collar 112. The cutting element 114, typically a polycrystalline diamond composite (PDC) cutting element, can be mounted in a cutting element recess 116 located near the front rotating surface 118 of each of the plurality of inserts 104.

[0010] Typically, the cutting element 114 consists of a thin layer of polycrystalline diamond 130 bonded to a sintered tungsten carbide substrate 132 at interface 128. The thin layer of polycrystalline diamond 130 forms a front cutting face 124 on the cutting element 114 of the prior art drill bit 100. The polycrystalline diamond layer is typically up to about 3.5 mm thick. These cutting elements 114 are typically cylindrical, with a diameter of about 8 mm to about 24 mm, and the peripheral edges of the polycrystalline diamond layer are typically chamfered to increase the impact resistance of the cutting teeth. However, the cutting element 114 can be other forms, such as elliptical or triangular, and can be larger or smaller than the dimensions described above. Typically, the cutting element 114 is manufactured separately from the drill body and fixed within a cutting element recess formed in the outer surface of the cutting tool. An adhesive material such as an adhesive or, more typically, a brazing alloy can be used to fix the cutting element 114 within the cutting element recess 116. The cutting element 114 can also be mechanically bonded to the cutting element recess 116.

[0011] The cutting element 114 drills into rock formations through shearing motions similar to those of a lathe, in contrast to a roller cone drill bit that drills by denting and crushing the rock. The cutting motion of the cutting element 114 plays a major role in the amount of energy required to drill into rock formations. Other factors influencing the amount of energy required to drill into rock formations include drill bit stability and drill bit mud.

[0012] Figure 2 This is a front view of a prior art fixed-blade rotary drill bit 100, showing multiple blades 104, chip flutes 106, nozzles 108, cutting elements 114, and cutting element recesses 116. Figure 2 This illustrates that when multiple inserts 104 have a large cutting edge curvature, the insert material adjacent to the cutting edge 124 of the cutting element 114 can extend beyond the cutting edge 124, thereby creating a flange 126. The flange 126 adjacent to the cutting edge 124 of the cutting element 114 can create a chip collection area, thereby reducing the hydraulic flow to the cutting element 114. The tendency for cutting material to accumulate around the insert face 120 of the drill body 102 and around the cutting element 114 is commonly referred to as "drill bit sludge." Drill bit sludge can damage the cutting element recess 116 in some applications.

[0013] Drill bit mud is typically caused by hydrated clay minerals or other materials adhering to the cutting element 114, the blade face 120 of the drill bit body 102, and / or the bottom borehole assembly of the drill string. From an operational perspective, drill bit mud problems are confirmed by increased pump pressure (due to obstruction of the flow path through the wellbore annulus), decreased penetration rate, clogging of the vibrating screen, and the necessary overstretching due to annular confinement during tripping (and possibly stuck drill).

[0014] Once drill bit mud packing is diagnosed, the conventional remedies are to increase the weight on the drill bit, add chemicals, and possibly pull the drill string out of the hole to clean the drill bit and bottom hole assembly. For water-based mud, detergents can be added to the drilling mud to reduce the ability of hydrated clay to adhere to the drill bit and bottom hole assembly. Adding approximately 3% to 4% of the system volume of ethylene glycol can also be used, but this usually does not solve the problem.

[0015] Preventative measures to minimize drill bit mud packing include the use of KCl / polymer or CaCl / polymer mud to prevent clay swelling. This is illustrated, for example, in U.S. Patent No. 4,984,643 to Isbell et al. Another approach to addressing drill bit mud packing is to direct nozzle discharge to optimize bottom hole cleaning in “mud-digging” configurations. This is reported, for example, in Smith et al., Hydraulics Optimization Research in Large Diameter Bits Reduces Operator's Variable Costs, AASDE-05-NTCE-58 (2005). Additionally, it has been reported that maintaining a negative potential of a few volts on the drill string assembly can release water at the interface between the drill bit and hydrated clay. See Sanjit et al., The effect of electro-osmosis on the indentation of clays, Proceedings of the 32nd American Conference on Rock Mechanics, Norman Okla (July 1991).

[0016] In addition to the above, drill bit design and selection can also affect drill bit mud packing. It is known that fixed-cutting-tooth drill bits are more prone to drill bit mud packing than tricone drill bits. Furthermore, the arrangement of the teeth on the drill bit can also affect drill bit mud packing. Figure 3 A detailed view of the rotating front surface 118 of one of a plurality of blades 104 in a prior art drill bit 100 having a cutting element 114 fixed in a cutting element recess 116 is shown. When the drill bit is designed with a large blade rake curvature, the blade material adjacent to the cutting element 114 can extend beyond the front cutting face 124 of the cutting element 114, creating a flange 126. The flange 126 can cause chip buildup, affecting the flow of drilling fluid around the cutting element 114, thereby impairing the ability of the cutting element 114 and the prior art drill bit 100 to effectively and efficiently engage formation material. Although remedies are indeed provided in the art, drill bit mud packing remains a significant factor affecting the cost of drilling new wells. Summary of the Invention

[0017] Therefore, an improved design for the steel drill bit body is needed to give it a larger cutting edge curvature to alleviate problems related to drill bit sludge buildup. Furthermore, reducing drill bit sludge buildup improves flow around the cutting surface of the cutting edge, thus enhancing the stability and durability of the cutting edge.

[0018] Some embodiments of this disclosure include a downhole drilling tool comprising a tool body and at least one cutting element extending from the tool body. The at least one cutting element includes a front rotating surface, at least one cutting element recess, and at least one cutting element at least partially fixed within the at least one cutting element recess. The at least one cutting element recess is formed in the at least one cutting element adjacent to the front rotating surface of the at least one cutting element and defines an inner surface corresponding to the shape of the cutting element. The at least one cutting element further includes at least one rounded transition surface located between the at least one cutting element recess and the front rotating surface of the at least one cutting element. The at least one rounded transition surface has a radius of curvature in the range of about 3 mm to 150 mm.

[0019] In another embodiment, this disclosure includes a downhole drilling tool comprising a tool body and at least one cutting element extending from the tool body. The at least one cutting element includes a front rotating surface, at least one cutting element recess, and at least one cutting element at least partially fixed within the at least one cutting element recess. The at least one cutting element recess is formed in the at least one cutting element adjacent to the front rotating surface of the at least one cutting element and defines an inner surface corresponding to the shape of the cutting element. The at least one cutting element further includes at least one linear transition surface located between the at least one cutting element recess and the front rotating surface of the at least one cutting element.

[0020] In another embodiment, this disclosure includes a method of manufacturing a downhole drilling tool, the method comprising: providing a tool body; forming at least one cutting element recess; forming at least one transition surface between the at least one cutting element recess and a rotating front surface of at least one cutting blade; and at least partially securing at least one cutting element within the at least one cutting element recess. The at least one cutting element recess defines an inner surface corresponding to the shape of the cutting element and extends into the at least one cutting blade adjacent to the rotating front surface of the at least one cutting blade; and the at least one transition surface has a radius of curvature in the range of about 3 mm to about 150 mm. Attached Figure Description

[0021] Figure 1 It is a fixed-cutting-tooth drill bit that rotates in the existing technology.

[0022] Figure 2 This is a front view of a conventional fixed-blade rotary drill bit.

[0023] Figure 3This is a detailed view showing the insert material adjacent to the cutting element, which extends beyond the front cutting face of the cutting element on a prior art fixed insert with a large front curvature.

[0024] Figure 4 This is a view of a fixed-blade rotary drill bit with a transition surface according to one embodiment.

[0025] Figure 5 This is a simplified view showing, in more detail, the transition surface adjacent to the cutting element recess according to one embodiment.

[0026] Figure 6 A linear transition surface adjacent to the cutting element is shown.

[0027] Figure 7 A rounded convex transition surface adjacent to the cutting element is shown.

[0028] Figure 8 A rounded concave transition surface adjacent to the cutting element is shown.

[0029] Figure 9A The front side of a prior art drill bit without a transition surface adjacent to the cutting element is shown.

[0030] Figure 9B The front side of a drill bit having a transition surface adjacent to the cutting element, according to one embodiment, is shown.

[0031] Figure 10A The prior art cutting insert and cutting element recess are shown, which do not have a transition surface adjacent to the cutting element recess.

[0032] Figure 10B An embodiment of a cutting blade having a transition surface adjacent to the recess of the cutting element is shown.

[0033] Figure 11A A prior art cutting tool without a transition surface adjacent to the cutting element is shown.

[0034] Figure 11B An embodiment of a cutting blade having a transition surface adjacent to the cutting element is shown.

[0035] Figure 12 It is a view of a transition surface partially disposed around the cutting element adjacent to the rotating front surface of the blade, according to one embodiment.

[0036] Figure 13 An inner surface of a mold for a drill bit body according to one embodiment is shown, the inner surface having features that correspond to the transition surface around the cutting element recess in the finished drill bit. Detailed Implementation

[0037] The illustrations presented herein are not actual views of any particular cutting assembly, tool, or drill string, but are merely idealized representations used to describe exemplary embodiments of this disclosure. The following description provides specific details of embodiments of this disclosure to provide a comprehensive description thereof. However, those skilled in the art will understand that embodiments of this disclosure can be implemented without using many of these specific details. In fact, embodiments of this disclosure can be implemented in conjunction with conventional techniques employed in the industry. Furthermore, the description provided below does not include all elements forming a complete structure or assembly. Only those process actions and structures necessary for understanding embodiments of this disclosure are described in detail below. Additional conventional actions and structures may be used. The accompanying drawings are for illustrative purposes only and are not drawn to scale. Additionally, common elements between the drawings may have corresponding numerical designations.

[0038] As used herein, the terms “having,” “comprising,” “including,” “characterized by,” and their grammatical equivalents are inclusive or open-ended terms that do not exclude additional undescribed elements or method steps, but also include the more restrictive terms “consisting of” and “substantially consisting of” and their grammatical equivalents.

[0039] As used herein, the term “may” in relation to a material, structure, feature, or method action indicates that it is contemplated for implementation of an embodiment of this disclosure, and is preferred over the more restrictive term “is” in order to avoid any implication that other compatible materials, structures, features, and methods that may be used in combination with it should or must be excluded.

[0040] As used herein, the term “constructed” refers to the dimensions, shape, material composition, and arrangement of one or more of a structure and one or more of a device that facilitate the operation of one or more of the structure and one or more of the device in a predetermined manner.

[0041] As used herein, the singular forms following “a,” “an,” and “the” are intended to include the plural forms as well, unless the context clearly indicates otherwise.

[0042] As used herein, the term “and / or” includes any and all combinations of one or more of the associated listed items.

[0043] As used herein, relational terms such as “first,” “second,” “top,” “bottom,” etc., are generally used for clarity and convenience in understanding this disclosure and the accompanying drawings, and do not imply or depend on any particular preference, orientation, or order unless the context clearly indicates otherwise.

[0044] As used herein, the term "substantially" with respect to a given parameter, characteristic, or condition means and includes to a certain extent that a person skilled in the art will understand that a given parameter, characteristic, or condition is satisfied with a certain degree of variance (such as within acceptable manufacturing tolerances). As an example, depending on whether a particular parameter, characteristic, or condition is substantially satisfied, it may be satisfied with at least 90.0%, at least 95.0%, at least 99.0%, or even at least 99.9%.

[0045] As used herein, the term “about” with respect to a given parameter includes the stated value and has a meaning determined by the context (e.g., it includes the degree of error associated with the measurement of the given parameter).

[0046] As used herein, the term “drilling tool” means and includes any type of drill bit or tool used for drilling during the formation or enlargement of a wellbore, and includes, for example, rotary drill bits, percussion drill bits, coring drill bits, eccentric drill bits, double-center drill bits, reamers, end mills, scraper drill bits, roller cone drill bits, hybrid drill bits, and other drill bits and tools known in the art.

[0047] According to embodiments of this disclosure, improvements in the flow characteristics of the cutting element, as well as improvements in cutting element efficiency and durability, can be achieved. Downhole drilling tools, including inserts with a large cutting edge curvature, may have a rounded transition surface between the insert material and the cutting element recess. The rounded transition surface provides improved flow characteristics around the cutting element and the drill bit face, greater insert durability, and improved mechanical efficiency, as described in further detail below.

[0048] Figure 4 This is a view of a fixed-blade rotary drill bit 200 with a transition surface 210 according to one embodiment. The drill bit 200 includes a plurality of blades 204, a chip flute 206, a nozzle 208, a cutting element recess 216, and a cutting element 214. Each of the plurality of blades includes a front rotating surface 218, a rear rotating surface 222, and a blade face 220 located between the front rotating surface 218 and the rear rotating surface 222. The cutting element recess 216 is formed in the blade face 220 adjacent to the front rotating surface 218 of at least one of the plurality of blades 204 and is generally shaped to receive the cutting element 214 and secure it to the drill bit body 202. The position of the cutting element recess 216 may be determined by the desired position of the cutting element 214 on the finished drill bit 200.

[0049] As described above, in drill inserts with a large cutting edge curvature, a portion of the insert material adjacent to the cutting edge 124 of the cutting element 114 can extend beyond the cutting edge 124 of the cutting element 114, thereby creating a flange 126 (e.g., Figure 2 , Figure 3 , Figure 9A and Figure 11A (As shown). The flange can create a chip collection area, thereby reducing the hydraulic flow to the cutting element 114, which may cause drill bit mud packing, drill bit instability, and may damage the cutting element pit 116.

[0050] Figure 4 A transition surface 210 is shown to be formed adjacent to at least one of the cutting elements 214 in the insert material of at least one of the plurality of inserts 204 to address this problem. In some embodiments, the transition surface 210 may be adjacent to a cutting element recess 216 formed in or cutting into the rotating front surface 218 and / or the insert face 220 of at least one of the plurality of inserts 204. The transition surface 210 may fully expose the front cutting face 224 of the cutting element 214 to improve the cutting efficiency and effectiveness of the cutting element 214. In addition, the transition surface 210 may improve the hydraulic flow around the insert face 220 and the cutting element 214 of the drill body 202. The transition surface 210 may also reduce chip buildup around the insert face 218 and the front cutting face 224 of the cutting element 214 of the drill body 202. Tests show that when the transition surface 210 is formed adjacent to the cutting element 214 in the front face 220 of the insert, the amount of chips (drill mud) around the front face 220 of the insert of the drill body 202 and around the front cutting face 224 of the cutting element 214 is significantly reduced.

[0051] Figure 5 This is a simplified view showing, in more detail, the transition surface 210 adjacent to the cutting element recess 216 according to one embodiment. The cutting element recess 216 is formed adjacent to a front rotating surface 218 on at least one of the plurality of cutting blades 204. The cutting element 214 may be at least partially fixed within the cutting element recess 216. The cutting element 214 typically includes a polycrystalline diamond mesa 230 bonded to a substrate 232 at an interface 228.

[0052] In some embodiments, a transition surface 210 may be formed in the insert material of at least one of the plurality of inserts 204 adjacent to at least one of the cutting elements 214. In some embodiments, the transition surface 210 may be formed in the insert material of at least one of the plurality of inserts 204 between the cutting element recess 216 and the front rotating surface 218 of the plurality of inserts 204. In some embodiments, the transition surface 210 may be formed in the insert material of at least one of the plurality of inserts 204 between the cutting element recess 216 and the front rotating surface 220 of the plurality of inserts 204. In some embodiments, the transition surface 210 may be formed in the insert material of at least one of the plurality of inserts 204 between the cutting element recess 216 and the front rotating surface 218 and the front rotating surface 220 of at least one of the plurality of inserts 204 (see [link to documentation]). Figure 10B , Figure 11B and Figure 12 ).

[0053] In some embodiments, a transition surface 210 formed in the insert material of at least one of the plurality of inserts 204 adjacent to at least one cutting element of cutting element 214 may substantially surround a portion of the front cutting face 224 of at least one cutting element of cutting element 214. In some embodiments, the transition surface 210 may be formed adjacent to one or more cutting elements of cutting element 214. In some embodiments, the transition surface 210 may be formed adjacent to most or all of the cutting elements of cutting element 214. In some embodiments, the transition surface 210 may be substantially uniform or similar. In some embodiments, one or more transition surfaces of transition surface 210 may be non-uniform or dissimilar.

[0054] In some embodiments, depending on the placement of the cutting elements 214, the transition surface 210 surrounding the first cutting element in the cutting elements 214 may be incorporated into the transition surface 210 surrounding the adjacent cutting elements 214 (e.g., Figure 10B , Figure 11B and Figure 12 (As shown). In some embodiments, the transition surface may extend away from the cutting element at a distance between 1 mm and 100 mm. In some embodiments, the transition surface 210 may extend into at least one of the plurality of blades 204 to a depth between 1 mm and 50 mm.

[0055] In some embodiments, the transition surface 210 may include a substantially concentric or circular surface surrounding the cutting element 214. In some embodiments, the transition surface 210 may include a semi-elliptical surface projecting away from the cutting element 214. In some embodiments, the transition surface 210 may include an eccentric or asymmetrical surface surrounding the cutting element 214.

[0056] Figure 6 An embodiment is shown in which one of the transition surfaces 210 comprises a linear surface located between the front rotating surface 218 of one of the plurality of blades 204 and the cutting element recess 216. In some embodiments, the transition surface 210 may comprise a linear surface located between the blade face 220 and the cutting element recess 216. The angle 211 of the linear surface of the transition surface adjacent to the cutting element recess 216 may be between about 1° and about 60° relative to the front rotating surface 218 of at least one of the plurality of blades 204 or relative to the blade face 220.

[0057] Figure 7 and Figure 8 An embodiment is shown in which the transition surface 210 defines a rounded surface 215 at the interface between the front rotating surface 218 and / or the cutting element recess 216, such that there are no right angles at any point between the front rotating surface 218 and / or the cutting element recess 216. Figure 7 As shown, in some embodiments, the rounded surface can be convex. For example... Figure 8 As shown, in some embodiments, the rounded surface 215 may be concave. In some embodiments, the rounded surface 215 may have a radius of curvature 217 between 1 mm and 500 mm. In some embodiments, the transition surface 210 between the blade face 220 and the cutting element recess 216 may include another more complex surface.

[0058] In some embodiments, features, such as ribs, ridges, and / or channels, may be formed adjacent to at least one of the cutting element recesses 216 in the cutting element material of at least one of the plurality of blades 204. Features, such as ribs, ridges, and / or channels, may improve hydraulic flow around the cutting element 214. In some embodiments, ribs, ridges, and / or channels may be parallel to each other. In some embodiments, ribs, ridges, and / or channels may not be parallel. In some embodiments, ribs, ridges, and channels may intersect each other or form a cross-shading pattern. In some embodiments, ribs, ridges, and channels may have a uniform width and / or height. In some embodiments, ribs, ridges, and channels may not have a uniform width and / or height. In some embodiments, ribs, ridges, and / or channels may be wavy.

[0059] In some embodiments, ribs, ridges, channels, and / or other features may be formed on at least a portion of one or more transition surfaces 210. In some embodiments, bumps, dimples (like golf balls), or other features may be formed in at least a portion of the surface of transition surface 210 to improve hydraulic flow around cutting element 214. Those skilled in the art will recognize that the particular shape, length, depth, and other configurations of transition surface 210 and the features within transition surface 210 may depend, for example, on the size of each of the plurality of blades 204, the size and placement of cutting element 214, and the intended use of the drill bit.

[0060] Figure 9A and Figure 9B It can be used by demonstrating the prior art drill bit 100 ( Figure 9A ) and drill bit 200 ( Figure 9B The front view of the existing technology drill bit ( Figure 9A ) and drill bit 200 ( Figure 9B Compare one implementation scheme of ). Figure 9A The front side of a prior art drill bit 100 without a transition surface adjacent to the cutting element 114 is shown. Figure 9A Also shown are a first prior art blade 152, a second prior art blade 154, a third prior art blade 156, a fourth prior art blade 158, a fifth prior art blade 160, a sixth prior art blade 162 and a seventh prior art blade 164. Figure 9B The front side of a drill bit 200 having a transition surface 210 adjacent to the cutting element 214 is shown according to one embodiment. Figure 9B The first blade 252, the second blade 254, the third blade 256, the fourth blade 258, the fifth blade 260, the sixth blade 262 and the seventh blade 264 are also shown.

[0061] Figure 9A and Figure 9B The front surfaces of the second, fourth, and sixth cutting blades 158, 258, and 162, 262 are shown to have significant curvature as they extend from the center of the drill body to its outer diameter. For example, line 219 shows that cutting blade 254 has a curvature of approximately 30° from the center of the drill body 202 to its outer edge. In contrast, note that the front surfaces of the first, third, fifth, and seventh cutting blades are substantially planar or flat, as shown in line 221. Prior Art Figure 9A Also shown is the insert material extending beyond the front cutting face 124 of the cutting element 114 adjacent to the insert material (marked in a box on the second prior art insert 154). The insert material extending beyond the front cutting face 124 of the cutting element 114 is referred to hereinafter as flange 126.

[0062] Figure 10A One of a plurality of blades 104 is shown, having a prior art cutting element recess 116 but without a transition surface. Figure 10B A blade is shown as one of a plurality of blades 204 having a transition surface 210 formed adjacent to a cutting element recess 216, according to one embodiment. Figure 10A and Figure 10B The cutting element recess 216 with transition surface 210 is shown in more detail. Figure 10B ) and prior art cutting element recesses 116 that do not have a transition surface. Figure 10A ) will incorporate multiple existing technology blades 104 ( Figure 10A One of the existing technology blades and multiple blades 204 ( Figure 10B Compare an implementation of one of the blades in the example. Figure 10B As shown, a transition surface 210 is formed by removing material from the rotating front surface 218 and the front face 220 of at least one of the plurality of inserts 204 via adjacent cutting element recesses 216. Material removal via adjacent cutting element recesses 116 can fully expose the front cutting face 224 of the cutting element 214 (e.g., ...). Figure 5 , Figure 11B and Figure 12 (as shown in the image).

[0063] Figure 10B An embodiment is shown in which the transition surface 210 is substantially concentric and symmetrical around each cutting element recess 216. Furthermore, the transition surface 210 substantially surrounds each cutting element recess 216 and merges together between adjacent cutting element recesses 216. In some embodiments, the width and depth of the transition surface 210 may be substantially uniform. In some embodiments, the width of the transition surface 210 may be substantially equal to the depth of the transition surface 210. In some embodiments, the surface of the transition surface 210 may be rounded. In some embodiments, the surface of the transition surface 210 may include a convex surface.

[0064] Figure 11A and Figure 11B This can be illustrated in more detail by showing the cutting element 114 located on the front rotating surface 118 of one of a plurality of blades 104 that do not have a transition surface. Figure 11A ) will use existing technologies ( Figure 11A ) and an implementation plan ( Figure 11B ) for comparison; and the front rotating surface 218 of one of the plurality of blades 204 according to one embodiment has a transition surface 210 substantially surrounding the cutting element 214. Figure 11B ). Figure 11AA flange 126 (boxed) extending through the front cutting face 124 of a prior art blade 104 of a plurality of prior art blades 114 with a large blade front curvature is shown. The flange 126 can cause chips to accumulate in its vicinity, affecting the flow of drilling fluid around the cutting element 114 and the rotating front surface 118 of the plurality of prior art blades 104, thereby impairing the ability of the cutting element 114 and the prior art drill bit 100 to effectively and efficiently engage formation material.

[0065] Figure 11B An embodiment of one of a plurality of inserts 204 is shown, having a transition surface 210 adjacent to the cutting element 214. The transition surface 210 exposes the entire front cutting face 224 of the cutting element 214 to the formation material, thereby improving the effectiveness of the plurality of inserts 204. The transition surface 210 also reduces chips collected from the vicinity of the cutting element 214 and improves the hydraulic flow around the rotating front surface 218 of the cutting element 214 and the plurality of inserts 204, thereby improving the stability of the drill bit 200.

[0066] Figure 12 A view of an embodiment of one of a plurality of blades 204 is shown, wherein a transition surface 210 cuts into the front rotating surface 218 and the blade face 220 of one of the blades 204. In this embodiment, the transition surface 210 is adjacent to and partially surrounds the front cutting face 224 of the cutting element 214. In some embodiments, the transition surface 210 may also cut into the blade face 220 of one of the blades 204 and may extend along the side surface 212 of the cutting element 214. In some embodiments, the transition surface 210 may be adjacent to the front cutting face 224 of the cutting element 214. In some embodiments, the surface of the transition surface 210 may conform to and / or correspond to the shape of the front cutting face 224 of the cutting element 214. In some embodiments, the transition surface 210 may be adjacent to the side surface 212 of the cutting element 214. In some embodiments, the surface of the transition surface 210 may conform to and / or correspond to the shape of the side surface 212 of the cutting element 214. In some embodiments, the transition surface 210 may be adjacent to the front cutting surface 224 and the side surface 212 of the cutting element 214. When the transition surface is formed adjacent to the front cutting surface 224 and the side surface 212 of the cutting element 214, the transition surface 210 may or may not have the same configuration around the front cutting surface 224 as it does around the side surface 212 of the cutting element 214.

[0067] According to one implementation plan, Figure 13 The diagram shows the formation of a matrix-type drill bit 200 (e.g.) Figure 4The feature portion 1002 is located on the inner surface of the mold cavity of the mold 1000 (as shown). When powder is placed into the mold 1000 and impregnated, the cutting element recess 216 and the associated transition surface 210 can be formed in the drill body 202 (e.g., Figure 4 (As shown). In some embodiments, feature 1002 may be machined into the inner surface of the mold cavity of mold 1000. In some embodiments, feature 1002 may be formed by milling or by some other process.

[0068] In other embodiments, the cutting element recess 216 and the transition surface 210 (such as...) Figure 4 (As shown) The transition surface 210 can be formed on a pre-formed steel drill bit using various material removal techniques. The transition surface 210 can be formed in a machining process at substantially the same time as drilling the cutting element recess 216. In some embodiments, the transition surface 210 can be formed after the cutting element recess 216 has been formed by a milling operation or some other process. In some embodiments, the transition surface 210 can be formed by various other processes known in the art, including, for example, electrical discharge machining (EDM), wire electrical discharge machining, chamfering tools, shot peening, or grinding.

[0069] Furthermore, in some embodiments, the transition surface 210 may have different geometries, may be formed at different times, and may be formed through different processes during the drill bit manufacturing process. Those skilled in the art will recognize that the form of the transition surface, the method of forming the transition surface, and the stage of the drill bit manufacturing process in forming the transition surface can depend on the specific method used to form the drill bit and the intended use of the drill bit.

[0070] In exemplary embodiments, a typical rotary "scraper" drill bit made of steel and using cutting elements is described. However, those skilled in the art will recognize that the size, shape, and / or configuration of the drill bit may vary depending on operational design parameters without departing from the scope of this disclosure. Furthermore, embodiments of this disclosure can be operated on non-rotating drill bits, and some embodiments are applicable to any drilling-related construction, including percussion, impact, or "hammering" drill bits. Additionally, although embodiments of this disclosure are described with respect to steel core drill bits, those skilled in the art will understand that they are applicable to drill bits made of other metals and their alloys, as well as other suitable materials. Those skilled in the art will also understand that one or more features of any illustrated embodiment may be combined with one or more features from another embodiment to form another combination as described herein within the scope of this disclosure. Therefore, although certain representative embodiments and details have been shown for the purpose of aiding in understanding the various embodiments, it will be apparent to those skilled in the art that various changes may be made to the embodiments disclosed herein without departing from the scope of this disclosure as defined by the appended claims and their legal equivalents.

[0071] Additional, non-limiting exemplary embodiments of this disclosure are described below.

[0072] Implementation Scheme 1: A downhole drilling tool comprising a tool body and at least one cutting element extending from the tool body. The at least one cutting element includes a front rotating surface, at least one cutting element recess, and at least one cutting element at least partially fixed within the at least one cutting element recess. The at least one cutting element recess is formed in the at least one cutting element adjacent to the front rotating surface of the at least one cutting element and defines an inner surface corresponding to the shape of the cutting element. The at least one cutting element further includes at least one rounded transition surface located between the at least one cutting element recess and the front rotating surface of the at least one cutting element. The at least one rounded transition surface has a radius of curvature in the range of about 3 mm to 150 mm.

[0073] Implementation Scheme 2: The downhole drilling tool according to Implementation Scheme 1, wherein the rotating front surface of at least one blade adjacent to at least one cutting element does not extend beyond the front cutting surface of at least one cutting element.

[0074] Implementation Scheme 3: The downhole drilling tool according to Implementation Scheme 1 or Implementation Scheme 2, wherein at least one rounded transition surface extends from at least one cutting element recess to the rotating front surface of at least one cutting blade by a distance between 5 mm and 50 mm.

[0075] Implementation Scheme 4: A downhole drilling tool according to any one of Implementation Schemes 1 to 3, wherein at least one rounded transition surface extends to a depth between 2 mm and 25 mm in the rotating front surface of at least one cutting edge.

[0076] Implementation Scheme 5: A downhole drilling tool according to any one of Implementation Schemes 1 to 4, wherein there is no right angle between at least one cutting element recess and the rotating front surface of at least one blade on the surface of at least one blade.

[0077] Implementation Scheme 6: A downhole drilling tool according to any one of Implementation Schemes 1 to 5, wherein at least one rounded transition surface comprises substantially concentric surfaces surrounding at least one cutting element.

[0078] Implementation Scheme 7: A downhole drilling tool according to any one of Implementation Schemes 1 to 6, wherein at least one rounded transition surface comprises a substantially elliptical surface protruding from at least one cutting element.

[0079] Implementation Scheme 8: A downhole drilling tool according to any one of Implementation Schemes 1 to 7, wherein at least one rounded transition surface includes an asymmetric eccentric surface adjacent to at least one cutting element.

[0080] Implementation Scheme 9: A downhole drilling tool according to any one of Implementation Schemes 1 to 8, wherein at least one rounded transition surface defines a convex surface.

[0081] Implementation Scheme 10: A downhole drilling tool according to any one of Implementation Schemes 1 to 9, wherein at least one rounded transition surface defines a concave surface.

[0082] Implementation Scheme 11: A downhole drilling tool according to any one of Implementation Schemes 1 to 10, wherein one or more of the blades of at least one blade of the downhole drilling tool have a blade front curvature radius greater than 15 cm.

[0083] Implementation Scheme 12: The downhole drilling tool according to any one of Implementation Schemes 1 to 11, the downhole drilling tool further includes at least one rounded transition surface extending from at least a portion of the side of at least one cutting element.

[0084] Embodiment 13: A downhole drilling tool comprising a tool body and at least one cutting element extending from the tool body. The at least one cutting element includes a front rotating surface, at least one cutting element recess, and at least one cutting element at least partially fixed within the at least one cutting element recess. The at least one cutting element recess is formed in the at least one cutting element adjacent to the front rotating surface of the at least one cutting element and defines an inner surface corresponding to the shape of the cutting element. The at least one cutting element further includes at least one linear transition surface located between the at least one cutting element recess and the front rotating surface of the at least one cutting element.

[0085] Implementation Scheme 14: A downhole drilling tool according to any one of Implementation Schemes 1 to 13, wherein the angle between at least one linear transition surface and the front rotating surface of at least one of at least one cutting blades is between 1° and 60°.

[0086] Implementation Scheme 15: A method of manufacturing a drilling downhole tool, the method comprising: providing a tool body; forming at least one cutting element recess; forming at least one transition surface between the at least one cutting element recess and a rotating front surface of at least one cutting blade; and at least partially securing the at least one cutting element within the at least one cutting element recess. The at least one cutting element recess defines an inner surface corresponding to the shape of the cutting element and extends into the at least one cutting blade adjacent to the rotating front surface of the at least one cutting blade; and wherein the at least one transition surface has a radius of curvature ranging from about 3 mm to about 150 mm.

[0087] Implementation Scheme 16: The method according to Implementation Scheme 15, the method further comprising removing any cutting tool material from the rotating front surface of the cutting tool that extends beyond the front cutting surface of the cutting tool adjacent to at least one cutting element.

[0088] Implementation Scheme 17: The method according to Implementation Scheme 15 or Implementation Scheme 16, the method further includes forming a tool body, at least one cutting element recess and at least one transition surface by casting.

[0089] Implementation Scheme 18: The method according to any one of Implementation Schemes 15 to 17, the method further comprising forming at least one transition surface by machining.

[0090] Implementation Scheme 19: The method according to any one of Implementation Schemes 15 to 18, wherein at least one transition surface is formed substantially simultaneously with at least one cutting element recess.

[0091] Implementation Scheme 20: The method according to any one of Implementation Schemes 15 to 19, the method further includes forming at least one transition surface by electrical discharge machining (EDM).

[0092] Although the scope of this disclosure is defined by the appended claims and their legal equivalents, the embodiments of this disclosure described above and illustrated in the accompanying drawings do not limit the scope of this disclosure, as these embodiments are merely examples. Any equivalent embodiments are intended to fall within the scope of this disclosure. In fact, various modifications to this disclosure beyond those shown and described herein (such as alternative useful combinations of the described elements) will become apparent to those skilled in the art based on the description. Such modifications and embodiments are also intended to fall within the scope of the appended claims and their legal equivalents.

Claims

1. A downhole drilling tool, the downhole drilling tool comprising: Tool body; At least one blade extending from the tool body, the at least one blade including a rotating front surface; At least one cutting element recess, the at least one cutting element recess defining an inner surface corresponding to the shape of the cutting element, and the front surface of rotation adjacent to the at least one cutting blade is formed in the at least one cutting blade; At least one rounded transition surface extends inward from the front rotating surface of the at least one insert to the opening of the at least one cutting element recess and surrounds at least a portion of the periphery of the at least one cutting element recess, the at least one rounded transition surface having a radius of curvature in the range of 3 mm to 150 mm; and At least one cutting element, said at least one cutting element being at least partially fixed within said at least one cutting element recess and having a rotating front end extending from said at least one cutting element recess to define a recess having said at least one rounded transition surface.

2. The downhole drilling tool of claim 1, wherein the rotating front surface of the at least one blade adjacent to the at least one cutting element does not extend beyond the front cutting surface of the at least one cutting element.

3. The downhole drilling tool according to claim 1 or 2, wherein the at least one rounded transition surface extends from the at least one cutting element recess to the rotating front surface of the at least one cutting blade by a distance between 5 mm and 50 mm.

4. The downhole drilling tool according to claim 1 or 2, wherein there is no right angle between the at least one cutting element recess and the front rotating surface of the at least one blade on the surface of the at least one blade.

5. The downhole drilling tool according to claim 1 or 2, wherein the at least one rounded transition surface comprises a substantially concentric surface surrounding the at least one cutting element.

6. The downhole drilling tool according to claim 1 or 2, wherein the at least one rounded transition surface comprises a substantially elliptical surface protruding from the at least one cutting element.

7. The downhole drilling tool according to claim 1 or 2, wherein the at least one rounded transition surface includes an asymmetric eccentric surface adjacent to the at least one cutting element.

8. The downhole drilling tool according to claim 1 or 2, wherein the at least one rounded transition surface defines a convex surface or a concave surface.

9. The downhole drilling tool according to claim 1 or 2, wherein one or more of the at least one blade of the downhole drilling tool has a blade front curvature radius greater than 15 cm.

10. The downhole drilling tool according to claim 1 or 2, wherein the downhole drilling tool further comprises at least one rounded transition surface extending from at least a portion of the side of the at least one cutting element.

11. A method for manufacturing a drilling downhole tool, the method comprising: A tool body is provided, the tool body having at least one blade extending from one end of the tool body; The at least one blade includes a rotating front surface; At least one cutting element recess is formed, the at least one cutting element recess defining an inner surface corresponding to the shape of the cutting element, and the front rotating surface adjacent to the at least one cutting blade extends into the at least one cutting blade; At least one transition surface is formed, the at least one transition surface extending from the front rotating surface of the at least one insert into the material of the at least one insert and extending to the opening of the at least one cutting element recess around at least a portion of the periphery of the at least one cutting element recess; as well as At least one cutting element is at least partially fixed within the at least one cutting element recess, wherein the rotating front end of the at least one cutting element extends from the at least one cutting element recess to be laterally adjacent to at least a portion of the depth of the at least one transition surface.

12. The method of claim 11, the method further comprising removing any cutting tool material from the rotating front surface of the cutting tool that extends beyond the front cutting surface of the at least one cutting element and is adjacent to the at least one cutting element.

13. The method according to claim 11 or 12, the method further comprising forming the tool body, the at least one cutting element recess, and the at least one transition surface by casting.

14. The method according to claim 11 or 12, the method further comprising forming the at least one transition surface by machining or electrical discharge machining (EDM).

15. The method according to claim 11 or 12, wherein the at least one transition surface is formed by machining substantially simultaneously with the at least one cutting element recess.

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