A hybrid wellbore drilling bit assembly and a method for drilling a borehole with a hybrid wellbore drilling bit assembly are described. A base connects the hybrid wellbore drill bit assembly to a drill string. Blades are connected to the base, extending away from the base along the longitudinal axis and tapering toward the longitudinal axis of the hybrid wellbore drilling bit assembly base creating a tapered cavity. The blades have cutters to shear a core of the Earth that enters the cavity. The core of Earth expands in the cavity. A crusher is connected to the base and positioned within the cavity which crushes the core of Earth.

A drill bit includes a bit body providing a plurality of blades disposed about a centerline of the bit body, one or more primary cutters mounted at a leading face of each blade, and one or more offset cutters mounted to at least one of the plurality of blades and angularly offset from a laterally adjacent primary cutter and the leading face of the at least one of the plurality of blades.

A polycrystalline element includes a table formed of polycrystalline diamond. The table includes a first surface; a second surface spaced apart from the first surface; and at least one side extending between the first surface and the second surface. The table also includes a plurality of extensions also formed of polycrystalline diamond, wherein at least one extension of the plurality of extensions extends away from at least one of the first surface and the at least one side. Optionally, the polycrystalline diamond of at least one extension of the plurality of extensions is contiguous with the polycrystalline diamond of the table. The polycrystalline element may be used in downhole tools for boring and well drilling, machine tools, and bearings.

A drill bit comprises a first and a second body received within the first body. Each of the first body and second body has a respective crown, each crown having an inner and an outer operative circumference. The outer operative circumference of the second body and the inner operative circumference of the first body can define a first volume that can receive a tubular core sample. The second body can define a break surface that breaks the tubular core sample into core pieces. The drill bit can be employed in a borehole with a reverse circulation system that pumps fluid around an outer surface of the bit, and returning fluid can carry the core pieces out of the borehole.

A drill bit comprises a first and a second body received within the first body. Each of the first body and second body has a respective crown, each crown having an inner and an outer operative circumference. The outer operative circumference of the second body and the inner operative circumference of the first body can define a first volume that can receive a tubular core sample. The second body can define a break surface that breaks the tubular core sample into core pieces. The drill bit can be employed in a borehole with a reverse circulation system that pumps fluid around an outer surface of the bit, and returning fluid can carry the core pieces out of the borehole.

A drill bit having a central axis can comprise a shank defining an inner bore and a crown having a cutting face. The crown can define an outer operative circumference. The crown can comprise a core-receiving slot in communication with the inner bore of the shank. One or more peripheral slots can be in communication with the inner bore of the shank. The crown can comprise one or more face channels that are in communication with the core-receiving slot and a respective peripheral slot. A base portion can be positioned within the core-receiving slot. The base portion can define a breaking surface. The peripheral slots can be configured to receive fluid moving in a distal direction toward the cutting face of the crown. The face channels can be configured to deliver fluid from the respective peripheral slot to the core-receiving slot.

A drill bit comprises a first and a second body received within the first body. Each of the first body and second body has a respective crown, each crown having an inner and an outer operative circumference. The outer operative circumference of the second body and the inner operative circumference of the first body can define a first volume that can receive a tubular core sample. The second body can define a break surface that breaks the tubular core sample into core pieces. The drill bit can be employed in a borehole with a reverse circulation system that pumps fluid around an outer surface of the bit, and returning fluid can carry the core pieces out of the borehole.

A casing-tube cutter bit applicable to both-directional rotation and having high excavation performance is provided. A casing-tube cutter bit includes a mounting part constituted by two members facing each other at a predetermined interval, and an excavation part formed continuously with the mounting part and having a leading end at which a plurality of ultrahard chips are disposed at a predetermined interval, the excavation part includes a central part, and first and second tilt parts tilted on both sides of the central part, the first tilt part is formed in a first length at a first tilt angle, the second tilt part is formed in a second length at a second tilt angle, the first tilt angle is equal to the second tilt angle, and the first length is shorter than the second length.

A mining bit includes: a shank; and cutting tips attached to the shank, each cutting tip having a plurality of layers and a plurality of abrasive particles, wherein the layers have a shape of an arch with flat surfaces in such a manner as to be laminated onto each other in a horizontal direction with respect to a cut surface of each cutting tip, and a distance (D2) between the abrasive particles on the adjacent layers is less than a distance (D1) between the abrasive particles on each layer.

A casing-tube cutter bit applicable to both-directional rotation and having high excavation performance is provided. A casing-tube cutter bit includes a mounting part constituted by two members facing each other at a predetermined interval, and an excavation part formed continuously with the mounting part and having a leading end at which a plurality of ultrahard chips are disposed at a predetermined interval, the excavation part includes a central part, and first and second tilt parts tilted on both sides of the central part, the first tilt part is formed in a first length at a first tilt angle, the second tilt part is formed in a second length at a second tilt angle, the first tilt angle is equal to the second tilt angle, and the first length is shorter than the second length.