Untitled record

The cutting factors used for earth boring tools and earth boring tools, including these cutting factors and the methods related to them

SHAPED CUTTING ELEMENTS FOR EARTH-BORING TOOLS, EARTH-BORING TOOLS INCLUDING SUCH CUTTING

ELEMENTS, AND RELATED METHODS

Full description

Background of the invention

In general, representations of the present invention relate to cutting elements including a table of superabrasive material (such as, for example, polycrystalline diamond or cubic boron nitride) formed on the substrate of earth-boring tools. Including these cutting agents and methods of forming and using these cutting agents and earth boring tools.

Earth boring tools are generally used to create (for example, drilling and reaming) bore holes or wells (hereafter wellbores) in earth formations. Earth drilling tools include, for example, rotary drill bits, core bits, eccentric bits, bicenter bits, reamers, underreamers, and mills.

The various types of earth‑boring rotary drill bits are known in the industry, including, for example, fixed‑cutter bits (often referred to in the industry as drag bits), rolling‑cutter bits (also referred to as drag bits). Often used in the field, such as rock bits, diamond-impregnated gears.

bits and hybrid bits (which may include, for example, both fixed cutters and rolling cutters). The drill bit rotates and advances in the subterranean formation. As the drilling gear rotates, cutters or abrasive structures cut, crush, shear and/or abrade away the formation material to form the well bore.

The drilling gear is coupled either directly or indirectly to the end of what is referred to in the field as a drill string, which includes a series of elongated tubular segments linked end-to-end that extend into the well bore from the surface of the formation. formation. Various tools and components, including the drilling gear, may often be coupled together at the distal end of the string of drilling columns at the bottom of the well bore to be drilled. This assembly of tools and components is referred to in the field as a bottom hole assembly (BHA).

The drilling gear may rotate within the well bore by the rotation of the series of drilling columns from the surface of the formation, or the drilling gear may rotate by coupling the drilling gear to the downhole motor in the bottom hole, which is also coupled to the series of drilling columns placed at the bottom of the wellbore. A downhole motor may include, for example, a hydraulic Moineau-type motor with a shaft that attaches to the drilling gear and which may cause the pumping fluid (such as drilling mud or fluid) to rotate from the formation surface downward. Through the center of the string of drilling columns, and through the hydraulic motor, Away from the nozzles in the drilling gear, but restored to the formation surface through the annular space between the outer surface of the string of drilling columns and the exposed surface of the formation within the well bore.

General description of the invention

Drilling gears for a cylindrical cutting tool typically include three roller cones attached to the supporting bit legs that extend from the bit body, which may, for example, consist of three bit head sections that are welded together to Form the gear structure. Each bit leg may consist of one bit head section. Each roller cone is installed in order to rotate quickly or rotate on the bearing shaft that extends from the bearing shaft in the inward and downward direction diagonally from the gear shaft. Cones are typically composed of steel but may also consist of particle-matrix composite material (such as a cermet composite such as cemented tungsten carbide). Cutting teeth may be able to cut through cutting rock and other land formations or otherwise form in or on the outer surfaces of each cone. Alternately, receptacles are formed on the outer surfaces of each cone, and inserts made of hard, wear-resistant material are included within the vessels to serve as cutting agents for the cones. As the drilling gear of the cylindrical cutting tool rotates within the well bore, the cylindrical cones are damaged and slide across the surface of the formation, which causes crushing and escape of the cutting agents away from the underlying formation.

Fixed‑cutter drill bits typically include multiple plurality of cutting elements attached to the face of the bit body. The gear structure may include many wings or blades, which define the fluid courses between the blades. The cutting elements may be secured to the gear structure within the pockets formed on the outer surfaces of the blades. The cutting agents are attached to the gear structure in a fixed manner, so that the cutting agents do not move relative to the gear structure during drilling. The gear body may consist of solid iron or a particle mold composite material (such as cobalt cemented tungsten carbide). In representations in which the gear structure includes the particle template composite material, the gear structure may be joined to a metal alloy shank (such as stainless steel) with a threaded end that may be used to join the gear structure and the shank to drill string. As the drilling gear of the cutting tool mounted within the well bore rotates, the cutting agents escape across the surface of the formation and cut away into the underlying formation.

Impregnated diamond rotary drill bits may be used to drill hard or abrasive rock formations such as sandstones. Typically, a diamond-inlaid drill gear has a solid head or crown that is cast in the mold. The crown is attached to a steel shank that has a serrated tip, a steel shank that may be used to attach the crown and steel shank to a string of drilling columns. A crown may have a variety of configurations and generally includes a cutting face including several cutting combinations, which may include at least one cutting segments, posts, and blades. The shafts and blades may be formed integrally with the crown in the mold, or they may be formed separately and joined to the crown. Channels separate from shafts and blades to allow drilling fluid to flow over the face of the gear.

Impregnated diamond bits may be composed such that the cutting face of the drill bit (including shafts and blades) includes the matrix material, which includes diamond particles dispersed through the matrix material. The die material itself may include a metal matrix material such as tungsten carbide particles, distributed throughout the die material such as a copper-based alloy.

It is known in the industry to use wear-resistant materials, such as hardfacing materials, to form-engage surfaces of rotating drill gears in order to reduce the wear of those surfaces of drill gears caused by abrasion. For example, abrasion occurs at the formation engagement surfaces of an earth boring tool when these surfaces engage and slide relative to the underground formation surfaces in the presence of solid particulate material (such as formation cuttings and detritus) carried by the drilling fluid. Conventional conventional drilling fluid. For example, hardfacing may be used for cutting teeth on the cones of cylindrical bevel gears as well as the engagement surfaces of the cones. The steel face may also be used for the exterior surfaces of the curved lower end or shirttail of each gear upright and other external surfaces of the drill gear that are likely to engage the formation surface during drilling.

The cutting agents used in these ground boring tools often include polycrystalline diamond cutters (often referred to as PDCs), which are cutting agents that include polycrystalline diamond (PCD) material. These polycrystalline diamond cutting elements are formed by sintering and bonding together relatively small diamond grains or crystals under conditions of high temperature and high pressure in the presence of a catalyst (such as cobalt, for example). , iron, nickel, or alloys and mixtures thereof) in order to form a layer of polycrystalline diamond material on the base material of the cutting agent. These processes are often referred to as high temperature/high pressure (or HTHP) processes. The cutting element substrate may include a cementitious material (i.e. a metal-ceramic composite material) such as, for example, cemented cobalt tungsten carbide. In these examples, cobalt (or other catalyst) may be drawn into the cutting agent base material into diamond grains or crystals during sintering and serve as a catalyst material to form the diamond disc from the diamond grains or crystals. In other methods, the powdered catalyst material may be mixed with diamond grains or crystals before the grains or crystals are sintered together in a high-temperature, high-pressure process.

When a diamond table is formed using a high-temperature, high-pressure process, crystalline material may remain in the interstitial spaces between the diamond grains and crystals in the resulting polycrystalline diamond table. The presence of the catalyst material in the diamond disc may contribute to thermal damage to the diamond disc when the cutting agent heats up during use as a result of friction at the contact point between the cutting agent and the composition. Diamond cutting agents are polycrystalline in which the catalyst material in the diamond disc generally remains thermally stable up to a temperature of about 750°C, although internal stress within the polycrystalline diamond disc may begin to develop at temperatures exceeding thermal expansion of about 350. Celsius . This thermal stress is at least partly the result of differences in thermal expansion rates between the diamond disc and the base material of the cutting agent to which it is bonded. This difference in thermal expansion rates may lead to compressive and tensile stresses at the interface between the diamond disc and the base material, and may cause delamination of the diamond disc from the base material. At temperatures of about 750 degrees Celsius and above, stresses within the diamond disc may increase significantly as a result of differences in the thermal expansion coefficients of the diamond material and the catalyst material within the diamond disc itself. For example, cobalt expands thermally much faster than diamond, which may cause cracks to form and propagate within a diamond disc, effectively leading to deterioration of the diamond disc and ineffectiveness of the cutting agent.

In order to reduce the problems associated with different rates of thermal expansion in polycrystalline diamond cutting agents, so-called thermally stable polycrystalline diamond cutting agents have been developed. This thermally stable polycrystalline diamond cutting agent may be formed by leaching the catalyst material (such as cobalt) away from the interstitial spaces between the diamond grains in the diamond disk using, for example, acid. All of the catalyst may be removed from the diamond disc, or only a portion may be removed. Thermally stable polycrystalline diamond cutting agents in which essentially all of the catalyst material has been filtered from the diamond disk are reported to be thermally stable up to temperatures of about 1200°C. It has also been mentioned, however, that these fully filtered diamond discs are brittle and relatively more vulnerable to shear stresses, compressive and tensile than unfiltered diamond discs. In an attempt to provide cutting agents with diamond discs that are more thermally stable relative to unfiltered diamond discs but are also relatively less brittle and vulnerable to shear, compressive and tensile stresses relative to fully filtered diamond discs, cutting agents have been supplied that include a disc. Diamonds in which only a portion of the catalyst material was leached from the diamond disc.

Brief explanation of the drawings

While the specifications, with the elements of protection in particular indicated and required in a distinct manner, are inferred from representations of the present invention, the various features and benefits of the present invention may be more easily realized than the following description of example representations in accordance with the invention provided with reference to the accompanying drawings, and Which contains:

Figure No. 1 is a side perspective view to represent the cutting operator according to the invention.

Figure No. 2 is a perspective view of the cutting operator shown in Figure No. 1, taken from a viewpoint approximately 45 degrees clockwise according to Figure No. 1.

Figure No. 3 is a frontal perspective view of the cutting operator shown in Figure No. 1, taken from a 90-degree clockwise point of view according to Figure No. 1.

Figure No. 4 is a side perspective view of the other representation according to the cutting factor according to the invention.

Figure No. 5 is a perspective view of the cutting agent shown in Figure No. 4, taken from a viewpoint of approximately 45 degrees in a clockwise direction according to Figure No. 4.

Figure No. 6 is a frontal perspective view of the cutting operator shown in Figure No. 4, taken from the viewpoint at approximately 90 degrees in a clockwise direction according to Figure No. 4,

Figure No. 7 is a perspective view to represent the ground hole rotary drilling gear for the cutting tool installed according to the invention which includes the cutting agents as described herein,

Figure 8 is a front view according to a representation of a rotary drilling gear for a cone-cylindrical ground hole according to the invention including cutting agents as described herein.

Figures 9 and 10 are side perspective views of the different representations according to the cutting agents in accordance with the invention, where the cutting agents are mounted on the drilling tool, which is equipped with a negative natural rear rake angle (such as a physical forward rake angle) and a negative effective rear rake angle. Negative effective back rake angle (such as a natural effective forward rake angle) relative to the surface of the formation,

Figures Nos. 11 and 12 are visual views of the different representations according to the cutting factors according to the invention, where the cutting agents are mounted on a drilling tool that is equipped with a positive natural back rake angle (such as the natural back rake angle) and a positive effective back rake angle (such as The effective back shelf angle (relative to the surface of the formation,

Figures Nos. 13 and 14 are side-view views of the different representations according to the cutting factors according to the invention, where the cutting agents are mounted on the drilling tool, which is equipped with the natural neutral back rake angle (such as the natural neutral rake angle) and the positive effective back rake angle (such as the The influential background shelf (relative to the surface of the formation,

Figures Nos. 15 and 16 are side-view views of the different representations of the cutting agents according to the invention, where the cutting agents are mounted on the drilling tool, which is equipped with a negative natural back rake angle (such as the natural front rake angle) and a positive, effective rear rake angle (such as the rear rake angle). Influencing) relative to the surface of the formation, and

Figures Nos. 17 and 18 are side perspective views of the different representations according to the cutting factors according to the invention, where the cutting agents are mounted on the drilling tool, which is equipped with a negative natural back rake angle (such as the natural front rake angle) and a neutral effective back rake angle (such as the The influential neutral cliff) relative to the surface of the formation.

Detailed description

Patterns of invention procedure

The illustrations provided herein are not intended to be actual representations of any particular cutter, ground boring tool or part of the cutter or tool, but only as exemplary representations that are used to describe the representations of the present invention. Additionally, commonalities between shapes may retain the same numerical designation.

As used herein, the term ground boring tool means and includes any tool used to remove formation material and to make a hole (such as a well bore) through the formation by removing formation material. Earth boring tools include, for example, rotary drill gears (such as fixed cutting tools, drilling gears, cylindrical cone gears, or rock gears), hybrid gears including both fixed sector tools and cylindrical drivers, center gears, road gears, two-center gears, and reamers. (Including expandable reamers and fixed-wing reamers), and the other is what is called a hole opening tool.

As used herein, the term vertex, when used in relation to a shaped cutting worker, means and includes a point farther away on the cutting edge of the shaped cutting worker relative to the center of a basal surface on the opposite side of the cutting worker.

With reference to Figures 1 and 3, the representation of the cutting factor 10 according to the invention is declared to include the longitudinal axis 11, the base 12 and the cutting tip 13. The base of the matrix 12 may have a generally cylindrical shape. The longitudinal axis 11 may extend through the center of the matrix base 12 in an orientation that may be at least essentially parallel to a lateral side surface 14 of the matrix base 12 (such as in an orientation that may be perpendicular to a generally circular cross section). Cross-section of the base material 12). A sub-side surface 14 of the base of the base material may be parallel and continuous with a common cylindrical sub-side surface 15 of the cutting tip 13. The cutting tip 13 also includes a general cylindrical surface 16, the apex 17, a flat cutting surface 18, and a general cylindrical sub-side surface 15. A general cylindrical surface 16 may be defined by the angle ф1 existing between a general conical surface 16 and a phantom line existing from a general cylindrical sub-surface 15 of the cutting tip 13. The angle ф1 may be within a range of about 30 60 degrees. A general conical surface 16 may extend from a generally cylindrical lateral side surface 15 to the apex 17, and may extend to the edges of the planar cutting surface 18. The exact location of the apex 17 may be centered around the longitudinal axis 11 . The planar cutting surface 18 may extend from the specified location at least substantially close to the apex 17 to the specified location on the cutting factor 10 at a chosen or predetermined distance from the apex 17, such that the angle α1 between the longitudinal axis 11 and the plane cutting surface 18 may be within Range of about 15 90 degrees.

In Figures 1 3, the angle ф1 is equal to about 30 degrees, the apex 17 of the cutting edge 13 is centered around the longitudinal axis 11 and the flat cutting surface 18 extends from the apex 17 to the sub-lateral surface 14 of the base of the base material 12. Consequently, the angle α1 is less than 30 degrees. Figure 1 shows a side perspective view of the cutting operator 10 displaying an asymmetric composition of the cutting tip 13 about the longitudinal axis 11 . Figure No. 2, which is a perspective view of the cutting agent 10 taken from approximately 45 degrees in the clockwise direction according to Figure No. 1, displays a flat cutting surface 18 of the cutting tip 13. Figure No. 3 shows a frontal perspective view of the cutting agent 10, taken from a viewpoint approximately 90 degrees in the clockwise direction according to Figure No. 1 in which the cutting edge 13 is symmetrical about the longitudinal axis 11.

With reference to Figures 4 and 6, another representation of the cutting factor 20 according to the invention is declared to include the longitudinal axis 21, the base of the base material 22, and the cutting tip 23. The matrix base 22 may have a general cylindrical shape. The longitudinal axis 21 may extend through the center of the matrix base 22 in an orientation that is at least substantially parallel to a sublateral surface 24 of the matrix base 22 (such as in an orientation that may be perpendicular to the general circular cross section of the matrix base 22). A sub-side surface 24 of the base material may be parallel and continuous with a general cylindrical sub-side surface 25 of the cutting tip 23. The cutting tip 23 also includes a general conical surface 26, an apex 27 and a flat cutting surface 28. A portion of a general conical surface 26 may extend between the edge of a plane cutting surface 28 and a general cylindrical subside surface 25 of the cutting tip 23. A general conical surface 26 may be defined by an angle ф2 located between a general conical surface 26 and an imaginary line extending from the general cylindrical sub-surface 25 of the cutting tip 23. The angle ф2 may be within a range of about 30 60 degrees. A conical surface 26 may extend from a cylindrical sub-side surface 25 to the apex 27 and may extend to the edges of a plane cutting surface 28. The exact location of the apex 27 may be offset from the longitudinal axis 21 . The plane cutting surface 28 may extend from the specified location at least substantially close to the apex 27 to the specified location on the cutting factor 20 at a chosen or predetermined distance from the apex 27, such that the angle α2 between the longitudinal axis 21 and the plane cutting surface 28 may be within Range of about 15 90 degrees.

In Figures 4 and 6, the angle ф2 is approximately 30 degrees, and the apex 27 is balanced from the longitudinal axis 21 and the flat cutting surface 28 extends from the apex 27 to the specified place on the generally conical surface 26 of the cutting tip 23. The angle α2 is approximately 60 degrees. See that the angles represented by the numbers 4 and 6 correspond respectively to those of the numbers 1 and 3.

Each of the cutting edges 13 and 23 may include polycrystalline diamond material. Specific areas of the cutting edges 13 and 23, or entire cutting edges 13 and 23, may optionally be treated (e.g., engraved) in order to remove the mineral bond between the intermediate diamond grains of the polycrystalline diamond material for each of the cutting edges 13 and 23, such that each of the cutting edges 13 is 23 is relatively more thermally stable. Each of the edges of the pieces 13 and 23 may be formed on the special bases of the material 12 and 22, or each of the ends of the pieces 13 and 23 and the bases of the special materials 12 and 22 may be formed separately and subsequently joined together. Both the base material bases 12 and 22 may consist of a material that is relatively hard and resistant to friction. As a non-limiting example, the bases 12 and 22 may be at least primarily composed of a cemented carbide material such as cobalt cemented tungsten carbide.

Each of the cutting agents 10 and 20 may be attached to the ground boring tool such that the respective cutting tips 13 and 23 will contact the surface of the underground formation within the well bore during the process of drilling or enlarging holes. Figure 7 is a simplified perspective view of a rotary drilling gear mounted cutting tool 100 that includes a plurality of cutting agents 10 and 20 attached to blades 101 on the drilling gear body 100. In additional representations, the drill gear 100 may include only cutting agents 10. In other representations to date, the drill gear 100 may include only the cutting agents 10 and 20 attached to the cylindrical cones 201 thereof. In additional representations, only the drill gear 200 may include cutting factors 10. In other representations to date, the drill gear 200 may include only cutting agents 20.

Referring to Figures 9 18, each of the cutting agents 10 and 20 may be attached to a portion 400 of the earth boring tool such that at least a portion of the respective flat cutting surfaces 18 and 28 contact the surface 300 of the underground formation within the well bore. Part 400 of an earth drilling tool may be a part of a rotary drill gear for earth boring for a fixed cutting tool, such as the drill gear 100, shown in Figure 7, or a part of a rotary drill gear for a cone-cylindrical ground hole, such as the drill gear 200, shown in Figure 8. The shape and composition of each of the cutting agents 10 and 20 may enable versatility in directing both the cutting agents 10 and 20 relative to the surface 300 of the underground formation.

With reference to Figures No. 9 18, the effective back shelf angles θ1 and θ2 between the special plane cutting surfaces 18 and 28 and the reference plane 500 are essentially perpendicular to at least the surface 300 of the underground formation that may be negative (i.e. the effective front shelf angle), Positive (i.e. the effective rear shelf angle), or neutral (i.e. the effective neutral shelf angle). The effective back rake angles θ1 and θ2 may be taken into account as negative, where the corresponding flat cutting surfaces 18 and 28 are behind the reference plane 500 in the direction of movement of the cutting tool (i.e. the flat cutting surfaces 18 and 28 form an obtuse angle with surface 300 for the underground formation). As shown in Figures Nos. 9 and 10. The effective back-rake angles θ1 and θ2 may be considered positive as the respective plane cutting surfaces 18 and 28 are before a reference plane 500 in the direction of movement of the cutting tool (i.e. the plane cutting surfaces 18 and 28 form an acute angle with the plane of Underground formation 300) as shown in Figures 11 and 16. The effective back shelf angles θ1 and θ2 may be considered neutral, where the special cutting plane surfaces 18 and 28 are parallel to the reference plane 500 (that is, the cutting plane surfaces 18 and 28 are essentially a right angle with the subterranean formation surface 300), as shown in Figures No. 17 and 18. In at least some representations, the effective rear rake angles θ1 and θ2 for the corresponding cutting factors 10 and 20 may be within a range from a negative rake angle of about 30 degrees to about a positive rake angle of approximately 45 degrees to the reference plane of 500. Clasts from the underground formation may deflect over and across the plane cutting surfaces 18 and 28 in directions that may be upward and away from the surface 300 of the underground formation.

The magnitude of the effective rake angles θ1 and θ2 may be determined at least in part by the orientation in which each of the special cutting factors 10 and 20 attaches to the ground boring tool. With continued reference to Figures 9 and 18, each of the cutting factors 10 and 20 may be attached to the ground boring tool to include the special back natural shelf angles π1 and π2, which may be negative (i.e. the front natural shelf angle) or positive (i.e. the back natural shelf angle). Natural), or neutral (i.e. the natural neutral cliff angle). The normal back shelf angles π1 and π2 may be considered negative where at least a portion of the special longitudinal axes 11 and 21 extending through the special cutting factors 10 and 20 are behind the reference plane 500 (i.e., the longitudinal axes 11 and 21 are obtuse to the surface of the subterranean formation 300 ), as depicted in Figures Nos. 9, 10 and 15 18 (the vertically opposite natural back shelf angles π1 and π2 should be known here). The normal back shelf angles π1 and π2 may be considered positive where at least part of the corresponding longitudinal axes 11 and 21 extended through the cutting factors 10 and 20 are the vertex of the reference plane 500 (i.e., the longitudinal axes form an acute angle with the surface of the subterranean formation 300). As shown in Figures 11 and 12 (the vertically opposite natural angles of the back shelf are π1 and π2, as you should know here). The natural back shelf angles π1 and π2 may be considered neutral, where the corresponding longitudinal axes 11 and 21 are parallel to the reference plane 500, as depicted in Figures 13 and 14.

Also, the magnitude of the effective back shelf angles θ1 and θ2 may be affected by the magnitudes of the angles α1 and α2 between the longitudinal axes 11 and 21 and the plane cutting surfaces 18 and 28, respectively. The magnitudes of the angles α1 and α2 may be affected at least by the specific specific locations of apex 17 and apex 27 on the corresponding cutting vertices 13 and 23, the length of the respective plane cutting surfaces 18 and 28 and the corresponding imaginary lines extending from the generally cylindrical sub-side surfaces 15 and 25 for factors Pieces 10 and 20.

The natural back rake angles π1 and π2, the size and shape of the flat cutting surfaces 18 and 28, and the effective back rake angles θ1 and θ2 of the cutting edges 13 and 23, respectively, may each be designed to improve the efficiency of the cutting agents 10 and 20 of the ground boring tool on To use and surface properties 300 for underground formation 300. The non-confined representations shown in Figures 9 and 18 include different combinations of these variables that may lead to effective background cliff angles θ1 and θ2 between about 30 degrees for a negative background angle and about 45 degrees for a positive background angle for the 500 reference plane.

Figures 9 and 10 show that the cutting agents may be formed and directed on the earth boring tool such that the corresponding natural back rake angles π1 and π2 are negative (i.e. a natural front rake angle) and the effective rear rake angles θ1 and θ2 are negative (i.e. the front rake angle). Influential). Figure No. 9 displays a side perspective view to represent the cutting factor 10 shown in Figure No. 1, as directed on the earth boring tool to include the natural back rake angle π1, which is negative. Figure No. 10 displays a side perspective view of the cutting agent 20 shown in Figure No. 4 as directed at the earth boring tool to include the natural back rake angle π2, which is negative. In the representations including relatively larger angles α1 and α2, the effective back shelf angles θ1 and θ2 may be closer to neutral. In representations including relatively larger angles α1 and α2, the corresponding normal shelf angles π1 and π2 may be more negative in order to smooth out the effective posterior shelf angles θ1 and θ2, which are negative. On the contrary, in representations including relatively smaller angles α1 and α2, the corresponding natural back shelf angles π1 and π2 may be negative to a lesser extent (i.e. closer to zero degrees), while still including the effective back shelf angles θ1 and θ2 which are negative.

Figures Nos. 11 and 12 show that the cutting factors 10 and 20 may be formed and directed on the earth boring tool such that the corresponding natural back rake angles π1 and π2 are positive (i.e. the natural back rake angle) and the respective effective back rake angles θ1 and θ2 are positive ( That is, the effective angle of the rear shelf. Figure No. 11 displays a side perspective view to represent the cutting factor 10 shown in Figure No. 1, as directed on the earth boring tool to include the natural back rake angle π1, which is positive. Figure No. 12 displays a side perspective view of the configuration of the cutting factor 20 shown in Figure No. 4, as shown with the ground boring tool, to include the natural back cliff angle π2, which is normal. In representations including relatively larger angles α1 and α2, the corresponding effective back shelf angles θ1 and θ2 may be more positive. In representations including relatively larger angles α1 and α2, the corresponding normal shelf angles π1 and π2 may be more negative in order to facilitate the effective back shelf angles θ1 and θ2, which are within 45 degrees of the positive back shelf angle relative to the reference plane of 500. Conversely, in representations including relatively smaller angles α1 and α2, the corresponding normal shelf angles π1 and π2 may be more positive while including the corresponding back shelf angles θ1 and θ2 are still within 45 degrees of the positive back shelf angle relative to the 500 reference plane.

Figures Nos. 13 and 14 show that the cutting factors 10 and 20 may be formed and directed on the earth boring tool such that the corresponding effective back rake angles θ1 and θ2 are positive (i.e. the effective back rake angle), and the respective natural back rake angles π1 and π2 are neutral. (i.e. the natural neutral cliff angle). Figure No. 13 shows a side view to represent the cutting factor 10 shown in Figure No. 1 as directed on the earth boring tool to include the natural back rake angle π1, which is neutral. Figure No. 14 displays a side perspective view to represent the cutting factor 20 shown in Figure No. 4 as directed on the earth boring tool to include the natural back rake angle π2, which is neutral. The magnitudes of the angles α1 and α2 may affect the sign and magnitude of the effective back shelf angles θ1 and θ2. In representations including relatively larger angles α1 and α2, the corresponding effective back shelf angles θ1 and θ2 may be closer to 45 degrees than the positive back shelf angle relative to the 500 reference plane. In the representations including relatively smaller angles α1 and α2, the effective back shelf angles θ1 and θ2 may be closer to neutral.

Figures Nos. 15 and 16 show that the cutting factors 10 and 20 may be composed and directed on the ground drilling tool such that the corresponding effective back shelf angles θ1 and θ2 are positive (i.e. the effective back shelf angle) and the respective natural back shelf angles π1 and π2 are negative ( That is, the normal frontal shelf angle). Figure No. 15 displays a side perspective view to represent the cutting factor 10 shown in Figure No. 1 as directed on the earth boring tool to include the natural back rake angle π1, which is negative. Figure No. 16 displays a side perspective view to represent the cutting factor 20 shown in Figure No. 4 as it is oriented on the earth boring tool to include the natural back rake angle π2, which is negative. In representations including relatively larger angles α1 and α2, the corresponding effective back shelf angles θ1 and θ2 may be more positive. In the representations including relatively larger angles and the corresponding effective back shelf angles, which may be more positive. In representations including relatively larger angles α1 and α2, the corresponding normal shelf angles π1 and π2 may be more negative in order to facilitate the effective back shelf angles θ1 and θ2, which are about 45 degrees equal to the positive back shelf angle with respect to the reference plane of 500 or less. On the contrary, in representations including relatively smaller angles α1 and α2, the effective back shelf angles θ1 and θ2 may be closer to neutral. In at least some representations including relatively smaller angles α1 and α2, the corresponding normal back shelf angles π1 and π2 may be positive enough to smooth out the effective back shelf angles θ1 and θ2, which are negative.

Figures Nos. 17 and 18 show that the cutting factors 10 and 20 may be composed and directed on the ground boring tool such that the corresponding effective back shelf angles θ1 and θ2 are neutral (i.e. the effective back shelf angle), and the natural back shelf angles π1 and π2 are negative ( That is, the natural front cliff angle). Figure No. 7 displays a side perspective view to represent the cutting factor 10 shown in Figure No. 1 as directed on the earth boring tool to include the natural back slope angle π1, which is negative. Figure No. 18 displays a side perspective view to represent the cutting factor 20 shown in Figure No. 4, as directed on the earth boring tool to include the natural back rake angle π2, which is negative. In representations including relatively larger angles α1 and α2, the corresponding normal back shelf angles π1 and π2 may be more negative in order to facilitate the corresponding effective back shelf angles θ1 and θ2, which are neutral. On the contrary, in representations including relatively smaller angles α1 and α2, the corresponding natural back shelf angles π1 and π2 may be more positive in order to facilitate the corresponding effective back shelf angles θ1 and θ2, which are neutral.

The improved form of the cutting agents described herein may be used to improve the behavior and durability of the cutting agents when drilling into subterranean formations. The shape of the cutting agents may allow the cutting agents to fracture and destroy the formation, while also providing increased efficiency in removing crushed formation material from the subterranean surface of the wellbore. The shape of the cutting agents may be used to provide an effective positive, negative, or neutral trailing rake angle, regardless of whether the cutting factor has a positive, negative, or neutral natural trailing rake angle.

While the present invention is described herein with respect to limited representations, those skilled in the art will recognize and appreciate that it is not limited. In particular, many additions, deletions and modifications to the representations described herein may be made without leaving the scope of the invention as hereinafter required including legal equivalents. In addition, features of this representation may be combined with features of another representation while still being included within the scope of the invention as intended by the inventor.