Fixed cutter drill bits are widely used in the petroleum and mining industry for drilling wellbores through earth formations. The bits typically include a bit body with a threaded connection at a first end for attaching to a drill string and cutting structure formed at an opposite end for drilling through earth formation. The cutting structure typically includes a plurality of blades that extend radially outwardly from a longitudinal axis of the bit body. Ultrahard compact cutters are typically mounted in sockets formed in the blades and affixed thereto by press fitting or brazing. Fluid ports may be positioned in the bit body to distribute fluid around the cutting structure of the bit and flush formation cuttings away from the cutters and borehole bottom during drilling.
Cutters used for fixed cutter drill bits typically include ultrahard compacts which include a layer of ultrahard material bonded to a substrate of less hard material through a high pressure/high temperature (HP/HT) sintering process, a brazing process, mechanical locking, or other means known in the art. For example, cutters may be formed having a substrate or support stud made of carbide, for example tungsten carbide, and an ultrahard cutting surface layer or table made of a polycrystalline diamond or polycrystalline boron nitride material deposited onto or otherwise bonded to the substrate at an interface surface. Cutters are conventionally cylindrical in form with circular cross sections.
This summary is provided to introduce a selection of concepts that are further described below in the detailed description. This summary is not intended to identify key or essential features of the claimed subject matter, nor is it intended to be used as an aid in limiting the scope of the claimed subject matter.
Embodiments disclosed herein relate to a cutting element that includes a body, a concave cutting face formed at a first end of the body, the cutting face including one or more cutting ridges adjacent a cutting tip that are raised above the concavity of the cutting face and having a length that is at least about 10% of a diameter of the cutting face. An edge is formed around a perimeter of the cutting face, the edge having an edge angle defined between a tangent of the cutting face and a cylindrical side surface of the body, the edge angle being acute at the cutting tip and varying around the perimeter of the cutting face.
Embodiments disclosed herein relate to a cutting element that includes a body, a concave cutting face formed at a first end of the body, the cutting face including one or more cutting ridges that are raised above the concavity of the cutting face. An edge is around a perimeter of the cutting face, the edge having an edge angle defined between a tangent of the cutting face and a cylindrical side surface of the body, the edge angle being acute at a cutting tip and varying around the perimeter of the cutting face. The cutting face includes a center dome that is raised above the concavity and is at a distance from the cutting tip.
Embodiments disclosed herein relate to a cutting tool that includes a tool body and at least one cutting element attached to the tool body. The cutting element includes a body, a concave cutting face formed at a first end of the body, the cutting face including one or more cutting ridges that are raised above the concavity of the cutting face and having a length that is at least about 10% of a diameter of the cutting face. An edge is around a perimeter of the cutting face, the edge having an edge angle defined between a tangent of the cutting face and a cylindrical side surface of the body, the edge angle being acute at a cutting tip and varying around the perimeter of the cutting face.
Embodiments disclosed herein relate to a cutting tool that includes a tool body, and at least one cutting element attached to the tool body. The cutting element includes a body, a concave cutting face formed at a first end of the body, the cutting face including one or more cutting ridges that are raised above the concavity of the cutting face. An edge is around a perimeter of the cutting face, the edge having an edge angle defined between a tangent of the cutting face and a cylindrical side surface of the body, the edge angle being acute at a cutting tip and varying around the perimeter of the cutting face. The cutting face includes a center dome that is raised above the concavity at a distance from the cutting tip.
Other aspects and advantages of the claimed subject matter will be apparent from the following description and the appended claims.
Embodiments disclosed herein may relate generally to cutting elements having a concave cutting face that may allow for a more positive rake angle than conventional cutters, thereby providing high cutting efficiency. Specifically, cutting elements in accordance with one or more embodiments of the present disclosure may include a concave cutting face that includes one or more cutting ridges raised above the concavity of the cutting face. The one or more cutting ridges may be disposed adjacent to a cutting tip. As described herein, the cutting face may have an edge formed around its perimeter that has an edge angle that is defined by a tangent of the cutting face and a cylindrical side surface of the body. The edge angle may be acute at the cutting tip and vary around the perimeter of the cutting face.
Cutting elements in accordance with the present disclosure generally include at least one cutting ridge 124 on the cutting face 120. The cutting ridges are raised from the cutting face so that when the cutting face is concave, for example, the ridges are raised above the concavity (e.g., above the general concavity) of the cutting face. The cutting ridges 124 of one or more embodiments of the present disclosure include two side portions 127 that are joined together at a top line 129. The top line of the cutting ridge runs along the length of the ridge and is disposed at the interface of the two side portions. The top line of the cutting ridge, along its length, may be concave, convex, serrated, or planar in shape, relative to the cutting face (i.e., along the z-axis). The top line of some embodiments, in a view perpendicular to the length, may be curved and, in particular embodiments, possess a radius having a lower limit of any of 0.030, 0.040, or 0.050 inches to an upper limit of any of 0.100, 0.125, or 0.150 inches, where any lower limit can be used in combination with any upper limit. In some embodiments, the cutting ridges may vary in thickness along their length, and can transition from either thin to thick or thick to thin along a radial direction from the center of the cutting face. The cutting ridges of one or more embodiments may have an inclusive angle ranging from a lower limit of any of about 60, 70, 80, 90, 100, or 125 to an upper limit of any of about 155, 160, 165, or 170 degrees, where any lower limit can be used in combination with any upper limit.
The cutting ridges may have any length suitable for the intended function of the cutting element. In some embodiments, the length of the cutting ridge may be measured as a percentage of a diameter of the cutting face. For example, in one or more embodiments, the cutting ridge may have a length of at least 5%, of least 10%, of at least 20%, or of at least 30% of a diameter of the cutting face. In embodiments where more than one cutting ridge is present, the ridges may be all the same length or they may each have a different length. In some embodiments, cutting ridges in accordance with the present disclosure may have a textured surface that, for instance, may include bumps or ripples.
In one or more embodiments depicted by
An edge 130 is formed around a perimeter of the cutting face 120 at the junction between the cutting face 120 and a side surface 112 of the cutting element 100. In some embodiments, such as shown in
The shape of an edge 130 may be described according to its cross-sectional profile along a plane intersecting the edge and perpendicular to the side surface at the edge. For example, a profile of an edge may include a curved transition between the cutting face and side surface portions at the edge, a bevel formed at the junction between the cutting face and side surface portions at the edge, or an angled transition between the cutting face and side surface portions at the edge. Further, an edge may have an edge angle defined between the cutting face and the side surface of the cutting element. For example, as shown in
Non-planar cutting faces according to embodiments of the present disclosure may include an undulating surface geometry, where relatively raised portions form two sides of the edge of a cutting element. In some embodiments, at least one raised portion may be formed between the outer raised portions at the edge and spaced apart by relatively depressed portions. For example, a single central raised portion in the shape of a ridge may be spaced between outer raised portions at a cutting element edge, or more than one ridge may be spaced between outer raised portions of a cutting element edge, where each raised portion may be spaced apart from each other by a relatively depressed portion. In some embodiments, a single central raised portion may be dome shaped, i.e., the central raised portion does not extend across the entire diameter of the cutting element but may be spaced a distance from the entire periphery. It is envisioned that the single central raised portion may be axisymmetric or not. In some embodiments, the single central raised portion may extend across a full width or diameter of the cutter, although in other embodiments a single central raised portion may extend along a partial width or diameter of the cutter. In embodiments in which a raised portion extends across a partial width or diameter of the cutter, the raised portion may extend from an outer edge toward a center or axis of the cutting face, or may extend from the center of the cutting face radially outward in a single or in each of opposing directions toward an outer edge.
In one or more embodiments, one or more cutting ridges may be sufficiently long as to intersect the center dome. When the dome is intersected by a cutting ridge, the cutting ridge may be disposed at most equal in height with the dome. This may enable more efficient lifting and peeling of the formation in some embodiments.
Depending on the orientation of the cutting element in a cutting tool and the relative orientation between the tool and the formation being engaged by the tool, certain portions of the edge may act as a cutting edge, which contacts and engages the formation. As used herein, the cutting tip is the first point of the cutting edge that contacts the formation upon increasing the cutting depth from 0. In some embodiments, cutting elements may be in a cutter pocket formed on a cutting tool such that a portion of the edge having an acute edge angle forms the cutting edge. In some embodiments, cutting elements may be oriented in a cutter pocket formed on a cutting tool such that a right or obtuse edge angle portion of the edge forms the cutting edge of the cutting element. Further, in some embodiments, a cutting element having a non-planar surface geometry, such as disclosed herein, may be rotated within a cutter pocket to alter the edge angle portion acting as the cutting edge, thereby altering the effective back rake angle (or engagement angle). In some embodiments, a cutting element having a first surface geometry (e.g., a planar or non-planar surface geometry) may be replaced with a cutting element having a non-planar surface geometry described herein to alter the edge angle acting as the cutting edge, thereby altering the engagement angle of the cutting element.
As used herein, an engagement angle refers to the angle measured between a line tangent to the portion of the cutting face to engage a formation and a line perpendicular to the formation being engaged (or working surface). The portion of a cutting face that engages a formation may depend on, for example, the distance the cutting element protrudes (extension height) from an outermost surface of the cutting tool on which the cutting element is disposed and the depth of cut of the cutting element. With cutting elements having a non-planar cutting face geometry at the cutting edge, such as disclosed herein, the engagement angle measured along the engagement area of the non-planar cutting face may vary along the depth of cut.
In one or more embodiments, cutting ridges in accordance with the present disclosure may be located in close proximity to the cutting edge. In some embodiments, one or more cutting ridges may be disposed generally, or substantially, perpendicular to a tangent of the edge at the cutting tip. In some embodiments, one or more cutting ridges may be radially disposed on the cutting face.
According to embodiments of the present disclosure, an engagement angle 360 formed at an acute edge angle portion of a cutting element may be positive, for example, within a range having a lower limit, an upper limit, or both lower and upper limits including any of 0°, 2°, 5°, 10°, 15°, 20°, 25°, 30°, 40°, 50°, or any values therebetween, where any relatively lower value may be selected in combination with any relatively higher value. If engagement angles disclosed herein were to be considered in terms of back rake angles for conventional cutting angles, positive back rake angles may not be achievable at the values described herein.
Further, in some embodiments of the present disclosure, an engagement angle 360 varying along a depth of cut may have a difference in value of greater than 2°, for example, up to 5°, up to 10°, or more. For example, an engagement angle formed along an engagement area having a concave cross-sectional profile may have a difference in engagement angles along the depth of cut of ranging from about 5° to about 15°, or more, depending on the radius of curvature of the concave cross-sectional profiles.
According to embodiments of the present disclosure, an engagement angle formed at a right edge angle portion of a cutting element may be negative, for example, having a lower limit, an upper limit, or both lower and upper limits including any of 0°, −2°, −5°, −10°, −15°, −20°, −25°, −30°, or any values therebetween, where any relatively lower value may be selected in combination with any relatively higher value. The engagement angle may be constant along the planar cross-sectional profile of the engagement area 421.
According to embodiments of the present disclosure, an engagement angle formed at an obtuse edge angle portion of a cutting element may be negative, for example, within a range having a lower limit, an upper limit, or lower and upper limits including any of −5°, −10°, −15°, −25°, −30°, −40°, −50°, or any value therebetween, where any relatively lower value may be selected in combination with any relatively higher value. The engagement angle may vary along the convex cross-sectional profile of the engagement area 521. In some embodiments, an engagement angle varying along a depth of cut may have a difference in value of greater than 2°, for example, up to 5°, up to 10°, or more. For example, an engagement angle formed along an engagement area having a convex cross-sectional profile may have a difference in engagement angles along the depth of cut of ranging from about 5° to about 15°, or more, depending on the radius of curvature of the convex cross-sectional profile. In embodiments having an obtuse edge angle with a planar surface forming the engagement area cross-sectional profile, the engagement angle may be constant or varied along the depth of cut.
Further, an engagement angle formed by a non-planar cutting face according to embodiments of the present disclosure may vary depending on the depth of cut. For example,
Non-planar cutting faces according to embodiments of the present disclosure may include an undulating surface geometry, where relatively raised portions form two opposite sides of the edge of a cutting element. In some embodiments, at least one raised portion may be formed between the outer raised portions at the edge and spaced apart by relatively depressed portions. For example, a single central raised portion (326) in the shape of a ridge may be spaced between outer raised portions at a cutting element edge, or more than one ridge may be spaced between outer raised portions of a cutting element edge, where each raised portion may be spaced apart from each other by a relatively depressed portion. In some embodiments, a single central raised portion may be dome shaped, i.e., the central raised portion does not extend across the entire diameter of the cutting element but may be spaced a distance from the entire periphery. It is envisioned that the single central raised portion may be axisymmetric or not. In some embodiments, the single central raised portion may extend across a full width or diameter of the cutter, although in other embodiments a single central raised portion may extend along a partial width or diameter of the cutter. In embodiments in which a raised portion extends across a partial width or diameter of the cutter, the raised portion may extend from an outer edge toward a center or axis of the cutting face, or may extend from the center of the cutting face radially outward in a single or in each of opposing directions toward an outer edge.
An edge of a cutting element according to embodiments of the present disclosure may have a bevel formed around the entire edge (such as the bevel shown in edge 830 in
According to embodiments of the present disclosure, a cutting element may include a canted, sloped side surface extending radially outward in a direction from a base surface of the cutting element toward the cutting face of the cutting element. The entire side surface or less than the entire side surface of a cutting element may be sloped outwardly in a direction from the base surface toward the cutting face of the cutting element.
In the embodiment shown in
Referring still to
In some embodiments, the side surface of a substrate of a cutting element may extend substantially parallel with a longitudinal axis of the cutting element, and the side surface around the entire perimeter of the cutting layer of the cutting element may extend in a radially outward direction from the interface to the edge. In some embodiments, the entire side surface of a cutting element may extend radially outward from the base surface of the cutting element to the cutting face of the cutting element. In some embodiments, the side surface around one or more portions of the cutting element perimeter may have an outwardly sloping profile from the base surface to the cutting face, while one or more other portions of the side surface may extend substantially parallel to the longitudinal axis from the base surface to the cutting face.
In some embodiments, a high portion at an end of a cutting element may include a planar, flat, or right surface adjacent an acute edge angle portion.
The cutting element 900 may have a body 910, a non-planar cutting face 920 having two outer raised regions and one or more cutting ridges disposed thereon (not shown for clarity), and an edge 930 extending around a perimeter of the non-planar cutting face 920. The height of the edge 930 varies around the perimeter of the cutting element 900, where the first, raised portion 932 of the edge 930 may extend higher than a second, depressed portion 934 of the edge 930. In one or more embodiments, the cutting element 900 may include a dome in a center of the cutting element 900, a ridge across the cutting element, and/or another raised portion 922.
The cutting element 900 differs from the above described cutting elements with respect to the edge angle by virtue of the incorporation of a flat portion adjacent the edge at the first, raised portion 932. In particular, the first, raised portion 932 may have an outermost edge angle of greater than 90° at the intersection with the bevel 931 (or with the side surface if there is no bevel 931). The first portion 932 may include a flat portion 935 (e.g., a generally flat portion) and an optional inclined portion 939. The edge angle 941 of the flat portion 935 (measured between the flat portion 935 and the side of the cutting element 900) may be about 90°, while the edge angle 937 of the inclined portion 939 may be an acute angle. At a depth of cut that exceeds the length of flat portion 935, the edge angle 937 is the effective edge angle that impacts engagement with the formation 950 and cutting efficiency. The acute edge angle 937 as measured between lines tangent to the inclined portion 939 and the side of the cutting element 900 is, in one or more embodiments, in a range that is greater than 35°, greater than 45°, or greater than 60° and up to 89°. In particular embodiments, the acute edge angle 937 may be between 65° and 75°.
At the first portion 932, the non-planar cutting face 920 may be piecewise continuous. For instance, adjacent the edge 930, the first, raised portion 932 may start from a flat top surface and transition into a valley of the second, depressed portion 934 (e.g., at an acute edge angle 937 of 50° to 85°). The flat portion 935 has been found to provide increased edge durability, and the size of the flat portion may be varied to achieve desired cutting efficiency and durability for a specific application. As shown in
While the flat portion 935 has been described as a chordal area, in other embodiments, the flat portion 935 may have other shapes. For instance, the flat portion 935 may not extend across a full chordal width. In other embodiments, the flat portion 935 may be annular and extend around a full or partial circumference of the cutting edge 930. In such embodiments, the length of the flat portion 935 may be constant (e.g., generally constant) around the full or partial circumference of the cutting edge 930 rather than as shown in
Two flat regions 935 are shown in
The third, raised portion 936 may be formed at a central region of the cutting face 920, spaced between the two first, raised portions 932 of the edge 930 having a flat portion 935 and an inclined portion 939, in which the inclined portion of the edge angles less than 90°. The raised portion 936 may also be spaced between the two second, depressed portions 934 of the edge having edge angles of about 90° or greater. The raised portion 936 may be raised and may extend a height less than, equal to, or greater than the first portions 932 of the edge 930. Further, the depressed portions 934 of the edge also extend a height less than the raised portions 932. In some embodiments, the depressed portions 934 also extend a height less than the central raised portion 936, but it may be greater than convex raised portions 936 in other embodiments.
In some embodiments, a raised portion of an edge may include multiple portions, but may not include a flat portion.
Cutting elements according to embodiments of the present disclosure may be secured to, or otherwise positioned on a cutting tool in an orientation to have a selected effective back rake, or engagement angle. For example,
The engagement angle formed between the cutting elements 1050, 1060 as they engage a formation may depend on the orientation of the cutter pocket in which the cutting elements are positioned, and the surface geometry of the cutting faces 1052, 1062. For example, an engagement angle may be varied by varying the orientation of a cutter pocket relative to the bit (varying the angle between the line tangent to the cutter pocket side wall relative to the cutting tool axis), and/or, an engagement angle may be varied by varying the surface geometry of a non-planar cutting face (e.g., such that a selected edge angle is provided as the cutting edge). In some embodiments, an engagement angle formed between a formation and a non-planar cutting element (having different edge angles formed around the edge of the non-planar cutting face) may be varied by rotating the non-planar cutting element within a cutter pocket to provide the different edge angles of the non-planar cutting face as the cutting edge. Accordingly, non-planar cutting elements according to embodiments disclosed herein may be used to alter one or more engagement angles on a cutting profile of an already formed cutting tool. Thus, in some embodiments, rather than (or in addition to) designing or altering a cutter pocket orientation relative to the cutting tool in which the cutter pocket is formed in order to provide a selected engagement angle between a cutting element in the cutter pocket and a formation, a non-planar cutting element according to embodiments of the present disclosure may be in an already formed cutter pocket to have an edge angle oriented in the cutting edge position in the cutter pocket in order to provide the selected engagement angle. In some embodiments, non-planar cutting elements 1050, 1052 may have a desired engagement angle while the cutter pocket is at a back rake angle that is between 5° and 50° or between 10° and 45°. This may include non-planar cutting elements 1050, 1052 in the cone, nose, shoulder, or gage regions of the bit, or in any combination of the cone, nose, shoulder, and gage regions of the bit.
Further, as shown in
According to embodiments of the present disclosure, an engagement angle may be altered by rotating a cutting element according to embodiments of the present disclosure within a cutter pocket formed on a cutting tool, such as a drill bit. For example, a drill bit may include a bit body having a longitudinal axis extending there through, at least one blade extending outwardly from the bit body, a cutter pocket formed in an outermost surface of the at least one blade, the cutter pocket having a side wall and a bottom wall, and a line tangent to the side wall extends downwardly from the longitudinal axis at an acute angle. A non-planar cutting element may be disposed in the cutter pocket, where the non-planar cutting element may include a body, a non-planar cutting face, and a cutting edge extending around a perimeter of the cutting face, and a plane tangent to a portion of the cutting face at the cutting edge forms a positive engagement angle (or effective back rake) with the longitudinal axis of the drill bit.
Non-planar cutting elements according to embodiments of the present disclosure may be disposed on a variety of downhole cutting tools, including, for example, drill bits, reamers, and other hole opening tools. For example,
While embodiments of the present disclosure have been described with respect to drill bits and other cutting tools for use in downhole applications, the present disclosure is not limited to such environments, and may be used in other environments, including manufacturing, and utility line placement. Numbers, percentages, ratios, or other values stated herein are intended to include that value, and also other values that are “about” or “approximately” the stated value, as would be appreciated by one of ordinary skill in the art encompassed by embodiments of the present disclosure. A stated value or terms such as “about,” “approximately,” “generally,” and the like, should therefore be interpreted broadly enough to encompass values, orientations, or features that are at least close enough to the stated value, orientation, or feature to perform a desired function or achieve a desired result. Stated values, features, and orientations include at least the variation to be expected in a suitable manufacturing or production process, and may further include deviations that are within 5%, within 1%, within 0.1%, or within 0.01% of a stated value, orientation, or feature. Where a range of values includes various lower or upper limits, any two values may define the bounds of the range, or any single value may define an upper limit (e.g., up to 50%) or a lower limit (at least 50%).
Although only a few embodiments have been described in detail above, those skilled in the art will readily appreciate that many modifications are possible in the embodiments without materially departing from this invention. It should be understood that references to “one embodiment” or “an embodiment” of the present disclosure are not intended to be interpreted as excluding the existence of additional embodiments that also incorporate the recited features. For example, any element or feature described in relation to an embodiment herein may be combinable with any element or feature of any other embodiment described herein. Accordingly, all such modifications are intended to be included within the scope of this disclosure. Equivalent constructions, including functional “means-plus-function” clauses are intended to cover the structures described herein as performing the recited function, including both structural equivalents that operate in the same manner, and equivalent structures that provide the same function. It is the express intention of the applicant not to invoke means-plus-function or other functional claiming for any claim except for those in which the words ‘means for’ appear together with an associated function.
This application is the U.S. National Phase of International Patent Application No. PCT/US2020/048310, filed Aug. 28, 2020, and entitled “POLYCRYSTALLINE DIAMOND CUTTING ELEMENT HAVING IMPROVED CUTTING EFFICIENCY,” which claims priority to and the benefit of U.S. Provisional Patent Application No. 62/893,831, filed on Aug. 30, 2019, each of which is hereby incorporated by reference in its entirety.
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Publishing Document | Publishing Date | Country | Kind |
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WO2021/041753 | 3/4/2021 | WO | A |
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