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.

The present disclosure provides a cutting head adapted to removably couple to a bit body of a drill bit assembly. The cutting head includes a leading cutting tip for cutting into earth and a trailing receiving portion for receiving a second end of the bit body in an internal cavity defined by the trailing receiving portion to allow the cutting head to be removably coupled to the second end of the bit body.

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 cutting tool with a plurality of cutting elements connected to a support structure wherein a portion of the support structure is configured to flex or bend based on the rotational frequency of the cutting tool. The rotational frequency of the cutting tool is a product of the design and composition of the tool.

Bottom hole assemblies for drilling through a lost circulation zone of a wellbore includes a drill string, a drill bit and a cladding seat coupled to the drill string, an expandable cladding sheath engaged with the cladding seat, a release mechanism coupling an uphole end of the expandable cladding sheath to the drill string, and an expander translatable axially along the drill string. The expandable cladding sheath is a fiber reinforced polymer. The cladding seat releasably couples a downhole end of the expandable cladding sheath to the drill string, and the release mechanism operates to release the uphole end of the expandable cladding sheath from the drill string. The expander deforms the expandable cladding sheath outward into contact with a wall of a wellbore when translated axially through a central cavity of the expandable cladding sheath. The bottom hole assembly may enable drilling ahead through a lost circulation zone.

Bottom hole assemblies for drilling through a lost circulation zone of a wellbore includes a drill string, a drill bit and a cladding seat coupled to the drill string, an expandable cladding sheath engaged with the cladding seat, a release mechanism coupling an uphole end of the expandable cladding sheath to the drill string, and an expander translatable axially along the drill string. The expandable cladding sheath is a fiber reinforced polymer. The cladding seat releasably couples a downhole end of the expandable cladding sheath to the drill string, and the release mechanism operates to release the uphole end of the expandable cladding sheath from the drill string. The expander deforms the expandable cladding sheath outward into contact with a wall of a wellbore when translated axially through a central cavity of the expandable cladding sheath. The bottom hole assembly may enable drilling ahead through a lost circulation zone.

A downhole tool, for selectively reaming a wellbore or stabilizing drill string components within a wellbore, includes an elongate tool body adapted to receive reamer cartridges or stabilizer cartridges. The reamer cartridges are radially insertable into corresponding pockets in the tool body, with each reamer cartridge having a reamer insert with an array of cutting elements. The reamer insert is disposed within a bushing and is rotatable relative thereto, about a rotational axis transverse to the longitudinal axis of the tool. However, the rotational axis is offset from the tool body axis, resulting in eccentric contact of the cutting elements with the wall of the wellbore, which in turn imparts rotation to the reamer insert when the tool is moved axially through a wellbore without rotation. When the tool is used for stabilization, the reamer cartridges are removed and replaced with stabilizer cartridges having stabilizer inserts with hard-faced stabilizer cones.

Rotatable elements for use with earth-boring tools include a movable element and a stationary element. The rotatable element may include a void within the support structure and at least one pin protruding from the void through an exterior side of the support structure. The rotatable element may further include at least one aperture configured to provide a vent to the void. The rotatable element may be disposed at least partially within a cavity of the stationary element. The stationary element may further include a track configured to interact with the at least one pin.