Abstract: A method for designing a fixed cutter drill bit, includes simulating the fixed cutter drill bit drilling in an earth formation, determining radial and circumferential components of imbalance forces on the drill bit and a Beta angle between the radial and circumferential components of the imbalance forces during a period of simulated drilling, and adjusting a value of at least one design parameter for the fixed cutter drill bit at least based upon the Beta angle. To facilitate drill bit design, the Beta angel can be displayed to a drill bit designer. To improve performance, the method can include repeating the simulating, determining, and adjusting to change a simulated performance of the fixed cutter drill bit. A drill bit may be made according to the design resulting from the method.

Abstract: A drill bit for drilling a borehole comprises a bit body having a bit face. In addition, the drill bit comprises a plurality of primary blades. Further, the drill bit comprises a plurality of primary cutter elements mounted to each primary blade and at least one backup cutter element mounted to each primary blade. Still further, the drill bit comprises a plurality of secondary blades. Moreover, the drill bit comprises a plurality of primary cutter elements mounted to each secondary blade. The ratio of the total number of backup cutter elements mounted to the plurality of primary blades to the total number of backup cutter elements mounted to the plurality of secondary blades is greater than 2.0. Each backup cutter element on each primary blade has substantially the same radial position as one of the primary cutter elements on the same primary blade.

Abstract: A PDC cutter including a body formed from a substrate material, an ultrahard layer disposed on the body, and a concave cutting face perpendicular to an axis of the body is disclosed. A PDC cutter including a body formed from a substrate material, an ultrahard layer disposed on the body, and a non-planar cutting face perpendicular to an axis of the body, the cutting face including a circumferential concave portion, and an inner protrusion portion is also disclosed.

Abstract: A polycrystalline diamond compact (“PDCD”) cutter includes a cylindrical body formed from a substrate material, an ultrahard layer disposed on the cylindrical body, and a cutting face perpendicular to an axis of the cylindrical body, wherein the cutting face includes two or more lobes and wherein the radius of at least one lobe is between 50 and 90 percent of the radius of the cylindrical body. A PDC cutter includes a substrate, and a cutting face perpendicular to an axis of the substrate, wherein the cross-section of the cutting face comprises multiple lobes, and the cross-section of the substrate is substantially circular.

Abstract: A drill bit for drilling a borehole in a formation, the drill bit including a bit body having a bit face including a cone region, a nose region, a shoulder region, and a gage region, at least one disjointed blade disposed on the bit face, the disjointed blade including a first section beginning proximate a central axis of the bit and extending less than full gage, and a second section beginning a selected distance from the central axis and extending to full gage, and a plurality of cutting elements mounted on the at least one disjointed blade is disclosed.

Abstract: A drill bit that includes a body having a lower end face for engaging a rock formation, the end face having a plurality of raised ribs extending from the face of the bit body and separated by a plurality of channels therebetween; at least one of the plurality of ribs having a varying width along at least a portion of a rib height is disclosed.

Abstract: In an embodiment, a drill bit for drilling a borehole comprises a bit body having a bit axis and a bit face. In addition, the drill bit comprises a primary blade extending radially along the bit face. Further, the drill bit comprises a plurality of primary cutter elements mounted to the primary blade. The primary blade is free of backup cutter elements. Still further, the drill bit comprises a secondary blade extending radially along the bit face. Moreover, the drill bit comprises a plurality of primary cutter elements mounted to the secondary blade. In addition, the drill bit comprises a first plurality of backup cutter elements mounted to the secondary blade in a first backup row that trails the primary row. Further, the drill bit comprises a second plurality of backup cutter elements mounted to the secondary blade in a second backup row that trails the first backup row.

Abstract: A drill bit for drilling a borehole in earthen formations comprising a bit body having a bit axis and a bit face. In addition, the drill bit comprises a primary blade extending radially along the bit face, the primary blade including a cutter-supporting surface that defines a blade profile in rotated profile view extending from the bit axis to an outer radius of the bit body. The blade profile is continuously contoured and includes a plurality of concave regions. Further, the drill bit comprises a plurality of cutter elements mounted to the cutter-supporting surface of the primary blade. Each cutter element on the primary blade has a forward-facing cutting face with a cutting edge adapted to penetrate and shear the earthen formation.

Abstract: A drill bit for drilling a borehole in earthen formations comprises a bit body including a cone region, a shoulder region, and a gage region. In addition the bit comprises a first primary blade and a second primary blade. Further, the bit comprises a plurality of primary cutter elements mounted to the first primary blade in different radial positions. Still further, the bit comprises a plurality of primary cutter elements mounted to the second primary blade in different radial positions. Moreover, a first primary cutter element of the plurality of primary cutter elements on the first primary blade and a first primary cutter element of the plurality of primary cutter elements on the second primary blade are each positioned in the cone region and are redundant. The shoulder region has a total cutter redundancy percentage that is less than a total cutter redundancy percentage in the cone region.

Abstract: A fixed cutter drill bit and a method for designing a fixed cutter drill bit includes simulating the fixed cutter drill bit drilling in an earth formation. A performance characteristic of the simulated fixed cutter drill bit is determined. A side rake angle distribution of the cutters is adjusted at least along a cone region of a blade of the fixed cutter drill bit to change the performance characteristic of the fixed cutter drill bit.

Abstract: A drill bit for drilling a borehole comprises a bit body having a bit face. In addition, the drill bit comprises a plurality of primary blades. Further, the drill bit comprises a plurality of primary cutter elements mounted to each primary blade and at least one backup cutter element mounted to each primary blade. Still further, the drill bit comprises a plurality of secondary blades. Moreover, the drill bit comprises a plurality of primary cutter elements mounted to each secondary blade. The ratio of the total number of backup cutter elements mounted to the plurality of primary blades to the total number of backup cutter elements mounted to the plurality of secondary blades is greater than 2.0. Each backup cutter element on each primary blade has substantially the same radial position as one of the primary cutter elements on the same primary blade.

Abstract: A fixed cutter drill bit and a method for designing a fixed cutter drill bit includes simulating the fixed cutter drill bit drilling in an earth formation. A performance characteristic of the simulated fixed cutter drill bit is determined. A side rake angle distribution of the cutters is adjusted at least along a cone region of a blade of the fixed cutter drill bit to change the performance characteristic of the fixed cutter drill bit.

Abstract: A fixed-head drill bit includes a bit body having a plurality of cutting elements and at least one wear knuckle disposed on the bit body. Each cutting element includes a cutting surface defining a swept cutting profile when the bit is rotated about an axis. The at least one wear knuckle is positioned at least partially within and extending at least partially outside a selected one or more of the swept cutting profiles, allowing the fixed-head drill bit to wear into a more stable configuration.

Abstract: A drill bit for drilling a borehole in earthen formations. In an embodiment, the bit comprises a bit body having a bit axis and a bit face. In addition, the bit comprises a pin end extending from the bit body opposite the bit face. Further, the bit comprises a plurality of gage pads extending from the bit body, wherein each gage pad includes a radially outer gage-facing surface. The gage-facing surfaces of the plurality of gage pads define a gage pad circumference that is centered relative to a gage pad axis, the gage pad axis being substantially parallel to the bit axis and offset from the bit axis.

Abstract: A method for designing a drill bit including characterizing a plurality of formation segments, identifying relevant characteristics for drilling in the characterized formation segments, prioritizing at least two of the identified relevant characteristics based upon the characterizing of the formation segments, and selecting a drill bit design based upon the prioritizing.

Abstract: A fixed cutter drill bit and a method for designing a fixed cutter drill bit includes simulating the fixed cutter drill bit drilling in an earth formation. A performance characteristic of the simulated fixed cutter drill bit is determined. A side rake angle distribution of the cutters is adjusted at least along a cone region of a blade of the fixed cutter drill bit to change the performance characteristic of the fixed cutter drill bit.

Abstract: A fixed cutter drill bit and a method for designing a fixed cutter drill bit includes simulating the fixed cutter drill bit drilling in an earth formation. A performance characteristic of the simulated fixed cutter drill bit is determined. A side rake angle distribution of the cutters is adjusted at least along a cone region of a blade of the fixed cutter drill bit to change the performance characteristic of the fixed cutter drill bit.

Abstract: A method for designing a fixed cutter drill bit includes simulating the fixed cutter drill bit drilling in an earth formation, determining a dynamic centerline trajectory of the drill bit, and adjusting at least one design parameter based upon the graphical display of at least the dynamic centerline trajectory. To improve performance, the method can include graphically displaying the dynamic centerline trajectory and/or repeating the simulating, determining, displaying and adjusting to change a simulated performance of the fixed cutter drill bit. A drill bit design may be selected and a drill bit may be made according to the design resulting from the method of designing.

Abstract: A method for designing a fixed cutter drill bit, includes simulating the fixed cutter drill bit drilling in an earth formation, determining radial and circumferential components of imbalance forces on the drill bit and a Beta angle between the radial and circumferential components of the imbalance forces during a period of simulated drilling, and adjusting a value of at least one design parameter for the fixed cutter drill bit at least based upon the Beta angle. To facilitate drill bit design, the Beta angel can be displayed to a drill bit designer. To improve performance, the method can include repeating the simulating, determining, and adjusting to change a simulated performance of the fixed cutter drill bit. A drill bit may be made according to the design resulting from the method.

Abstract: A fixed-head drill bit includes a bit body having a plurality of cutting elements and at least one wear knuckle disposed on the bit body. Each cutting element includes a cutting surface defining a swept cutting profile when the bit is rotated about an axis. The at least one wear knuckle is positioned at least partially within and extending at least partially outside a selected one or more of the swept cutting profiles, allowing the fixed-head drill bit to wear into a more stable configuration.