Abstract: An earth boring drill bit designed for a specific performance, within a finished product tolerance, using components built to a looser manufacturing tolerance. The bit may be assembled by selecting a leg from a plurality of pre-manufactured legs; selecting a bit body from a plurality of pre-manufactured bit bodies, the bit body having a slot for receiving the leg; placing the leg within the slot; and fixing the leg within the slot within the finished product tolerance by placing one or more shims between the leg and the slot. The shims may be used to adjust an axial position, a radial position, and/or a circumferential position of the leg with respect to the slot. The leg and the bit body may be selected, or produced, to ensure the bit will not meet the specification, given the manufacturing tolerance, without the shims.

Abstract: A method of designing a drill bit includes: defining a representation of a first drill bit including at least a first cutter having a first face, the first cutter being disposed on the representation of the first drill bit in a first orientation; simulating in a first simulation on a computing device off-axis rotation of the first drill bit in a simulated subterranean formation; determining that the first face included, during the first simulation, a first face orientation direction that was oriented different than a face cutting direction by an amount that exceeds a predetermined threshold; and defining the first drill bit such that the first cutter is disposed in a second orientation.

Abstract: The invention provides drill bits and methods of drilling curved boreholes. One aspect of the invention provides a drill bit including a bit body and one or more blades positioned within the bit body, the one or more blades individually actuatable to a plurality of cut depths. Another aspect of the invention provides a method for drilling a curved borehole. The method includes: providing a drill string including a drill bit including a bit body and one or more blades positioned within the bit body, the one or more blades individually actuatable to a plurality of cut depths; rotating the drill string; and selectively actuating the one or more blades to a plurality of cut depths; thereby drilling a curved borehole.

Abstract: A rotary drill bit for drilling a subterranean formation may comprise a bit body, a cutting element coupled to the bit body, and a torque-generating assembly configured to apply torque, either continuously or periodically, to the cutting element. The torque-generating assembly may be powered by the rotary motion of the rotary drill bit or may be hydraulically or electrically powered. The cutting element may comprise a substrate, a table of superabrasive material disposed on an end of the substrate, and at least one impelling feature formed along the exterior surface of the substrate. In addition, a method of rotating a cutting element coupled to a drill bit for drilling a subterranean formation may comprise providing a cutting element comprising a table bonded to a substrate, coupling the substrate of the cutting element to a drill bit body, and applying torque to the substrate of the cutting element.

Abstract: A rotary drill bit having blades with cutting elements disposed on exterior portions thereof may be formed with either a continuous cutting zone or a substantially continuous cutting zone between the last cutting element on each blade and an adjacent gage pad. Such rotary drill bits may have improved steerability during the formation of a directional wellbore and/or may experience substantially reduced wear on gage pads and/or portions of each blade adjacent to respective gage pads. For some rotary drill bits an additional cutter may be disposed in one or more gage pads adjacent to the last cutting element. For other rotary drill bits a gage cutter may be disposed between and in close proximity to both the last cutting element and adjacent portions of the associated gage pad.

Abstract: A rotary drill bit for drilling a subterranean formation may comprise a bit body, a cutting element coupled to the bit body, and a torque-generating assembly configured to apply torque, either continuously or periodically, to the cutting element. The torque-generating assembly may be powered by the rotary motion of the rotary drill bit or may be hydraulically or electrically powered. The cutting element may comprise a substrate, a table of superabrasive material disposed on an end of the substrate, and at least one impelling feature formed along the exterior surface of the substrate. In addition, a method of rotating a cutting element coupled to a drill bit for drilling a subterranean formation may comprise providing a cutting element comprising a table bonded to a substrate, coupling the substrate of the cutting element to a drill bit body, and applying torque to the substrate of the cutting element.

Abstract: A method for designing a drill bit that involves simulating a drill bit having cutting elements disposed thereon is provided. In particular, the method involves determining at least one drilling performance parameter while simulating drilling in a selected earth formation.

Abstract: The invention is an attachment means for a ground drilling or cutting tool (10) that enables cutting elements (11) to be removably secured to the tool (10). The attachment means include a first surface (13) on the cutting element (11), a second surface (14) on the tool (10) upon which the first surface (11) locates, dowel holes (15) in each of the first and second surfaces, dowels (16) that locate in aligned dowel holes between said surfaces, engagement surfaces (17, 18) on the cutting element and tool that extends substantially parallel to the longitudinal axis of the tool and engage to resist side loads applied to the cutting elements (11) and fastening means (19) that secures the cutting elements (11) to the tool (10). The invention provides a means of easily removing the cutting elements (11) from the tool (10) for either replacement or maintenance work.

Abstract: An expandable drill bit comprises a body for mounting on a support string and two roller cutters mounted on the body. The cutters are movable between a smaller diameter first configuration and a larger diameter second configuration. In one embodiment the bit is adapted to drill with the cutters in both the first and second configurations.

Abstract: A roller cone bit may be used as a rotating drag bit by treating the roller cones as carriers for a plurality of distinguishable types of drag cutters. The roller cones are each coupled to a mechanism which selectively allows rotation of the roller cones. The roller cones are otherwise fixed and as the bit is rotated, the drag cutters are brought into engagement with the rock. However, where the roller cones are selectively allowed to rotate, rotation of the drag bit rotates the roller cones to bring a second set of drag cutters into a configuration for cutting the rock formation. A mechanism then selectively locks the roller cones to prevent further rotation, keeping the second set of drag cutters fixed in place. By selectively permitting and preventing rotation of the roller cones, a plurality of sets of drag cutters can be brought into a configuration for cutting the rock.

Abstract: A rotary cutter assembly comprises a drill head having a plurality of receptacles which releasably receive rolling cutter bit assemblies. The bit assemblies are locked in position by a locking sleeve connecting transverse fluid passageways of the drill head and bit assembly. Radially locking means in the form of pins received in complementary slots parallel to the rotational axis of the rotary cutter assembly are also provided.

Abstract: An earth boring bit is shown of the type used to cut a shaft in the earth. The earth boring bit has a central bit body which is adapted to be driven to cut a shaft and which has an outer conical surface thereon. An outer ring segment carried on the central bit body has a conical surface for matingly engaging the central bit body conical surface whereby torque transmitted to the outer ring is transmitted through the mating conical surfaces to drive the central bit body to cut a shaft. The mating conical surfaces are preloaded to assure drivable contact between the surfaces. The effective cutting diameter of the earth boring bit can be varied by interchanging the outer ring segment.

Abstract: A bit is provided that includes a bit body defining a bit axis of rotation. Primary cutter means are positioned on the bit body for disintegrating the formations out to a first radial distance from said bit axis of rotation. Secondary cutter means are adapted to be connected to the bit body and selectively located in a first position for cutting between said first radial distance and a larger second radial distance and selectively located in a subsequent position between said first radial distance and an even larger subsequent radial distance. Expansion means are provided to be located between said secondary cutter means and said bit body for locating said secondary cutter means in said subsequent position.