Abstract: A method and apparatus for reaming or enlarging a borehole with the ability to drill cement, cement float equipment, and debris out of a casing without substantial damage to the casing interior or the reaming apparatus. The reaming apparatus also provides enhanced protection from contact with the casing wall for selected structural features and elements thereof.

Abstract: A rotary-type earth-boring drag bit with cutters oriented at varied rake angles and methods for designing such drag bits. Specifically, cutters that are located sequentially adjacent radial distances from a longitudinal axis of the drill bit have cutting faces that are oriented at rake angles that differ from one another. These cutters may be located on the same blade of the drag bit or on different blades of the drag bit.

Abstract: Enhanced stabilization is provided for an eccentric reaming tool when a pilot borehole is undersized with respect to a following pilot stabilization pad (PSP). Alternatively, offset of a rotational axis of at least a portion of the assembly including the reaming tool is employed to accomplish stabilization of the reaming tool. In either case, a reamed diameter larger than a physical diameter of the reaming tool may be drilled. More specifically, an enlarged PSP relative to pilot bit diameter or PSP offset or even pilot bit offset is employed in order to engage a PSP with the wall of a pilot borehole of greater diameter than a physical diameter of the pilot bit. The PSP or pilot drill bit, or both, may be laterally offset, angularly offset, or a combination thereof in order to effect substantially continuous PSP contact with the pilot borehole wall.

Abstract: A rotary-type earth-boring drag bit with cutters oriented at varied rake angles and methods for designing such drag bits. Specifically, cutters that are located sequentially adjacent radial distances from a longitudinal axis of the drill bit have cutting faces that are oriented at rake angles that differ from one another. These cutters may be located on the same blade of the drag bit or on different blades of the drag bit. The rake angles at which the cutting faces of these cutters are oriented may be based, at least in part, on the relative radial distances these cutters are spaced from the longitudinal axis of the drag bit, on the vertical positions of these cutters along the longitudinal axis of the drag bit, or in response to actual or simulated evaluations of the use of the drag bit to drill a subterranean formation.

Abstract: A cutter and a drill bit having such cutters for drilling subterranean formations including a superabrasive table formed on an end face of a supporting substrate, there being an interface between the table and the end face including a topographic configuration including at least one, and preferably a plurality of, annular arcuate surfaces centered about the centerline of the cutter and at least one recessed region or groove extending across a substantial portion of the end face. The topographic configuration of the end face is of an orientation and radial width sufficient to accommodate resultant loading of the cutting edge of the cutter throughout a variety of angles with vectors normal to the surface at a variety of angles such that at least one normal vector is aligned substantially parallel to the resultant loading on the cutting edge.

Abstract: A method and apparatus for reaming or enlarging a borehole with the ability to drill cement, cement float equipment, and debris out of a casing without substantial damage to the casing interior or the reaming apparatus. The reaming apparatus also provides enhanced protection from contact with the casing wall for selected structural features and elements thereof.

Abstract: A rotary-type earth-boring drag bit with cutters oriented at varied rake angles. Specifically, cutters that are located sequentially adjacent radial distances from a longitudinal axis of the drill bit have cutting faces that are oriented at rake angles that differ from one another. These cutters may be located on the same blade of the drag bit or on different blades of the drag bit. The rake angles at which the cutting faces of these cutters are oriented may be based, at least in part, on the relative radial distances these cutters are spaced from the longitudinal axis of the drag bit, on the vertical positions of these cutters along the longitudinal axis of the drag bit, or in response to actual or simulated evaluations of the use of drag bit to drill a subterranean formation. Methods for designing drag bits are also disclosed.

Abstract: An earth-boring bit has a rotating cutter of a hybrid design. The bit has a bit body and a bearing shaft which is cantilevered downwardly and inwardly from the bit body. The cutter is mounted for rotation on the bearing shaft and has a plurality of cutting elements arranged in circumferential rows on the cutter. These rows include inner rows and a heel row. The cutting elements in the inner row are formed of a hard metal such as tungsten carbide and are pressed interferingly into apertures in the cutter. The heel row is made up of steel teeth formed on the cutter.