The disclosure provides a drill bit including a bit body and a blade extending from the bit body. The blade includes a first element protruding from a surface of the blade and a second element protruding from the surface of the blade. The first element and the second element are each configured to extend or retract relative to the surface of the blade and are coupled to each other such that when the second element retracts relative to the surface of the blade, the first element extends relative to the surface of the blade. The first element is disposed within a first pocket formed in the surface of the blade, and the second element is disposed within a second pocket formed in the surface of the blade. A communication channel is formed between the first pocket and the second pocket.

A modular reamer shoe for connection to an end of a tubular structure, such as a casing or liner, for deployment in a wellbore includes a body configured for connection to the tubular structure (casing or liner). The body includes a first section and an adjacent second section. The first section is connected to the second section such that torque can be transmitted between the first section and the second section. The first section defines a starter reamer defined by a plurality of first cutting elements and second cutting elements spaced from the first cutting elements. The reamer shoe has a plurality of actuatable blades disposed within the second area of the first section. The plurality of blades moves between extended positions and retracted positions. A nose is connected to the first section of the body. The second section is actuatable and can move in an axial direction so as to move the body, including the nose, in forward/rearward directions.

The disclosure provides a drill bit including a bit body and a blade extending form the bit body. The blade includes a first element protruding from a surface of the blade and a second element protruding from the surface of the blade. The first element and the second element are each configured to extend or retract relative to the surface of the blade and are coupled to each other such that when the second element retracts relative to the surface of the blade, the first element extends relative to the surface of the blade. The first element is disposed within a first pocket formed in the surface of the blade, and the second element is disposed within a second pocket formed in the surface of the blade. A communication channel is formed between the first pocket and the second pocket.

Bottom hole assemblies with a combined roller-underreamer assembly can include: a body configured to be attached to a drill pipe; an uphole ring attached to the body; a downhole ring attached to the body between the uphole ring and the downhole end of the body; a sliding ring mounted around the body between the uphole ring and the downhole ring; a set tube slidably mounted around the body between the uphole ring and the sliding ring; a reamer assembly with at least one first articulated arm with extending between the uphole ring and the downhole end of the set tube; and a roller assembly with: at least one second articulated arm extending between the uphole end of the set tube and the sliding ring; and a rolling positioned at a joint of each second articulated arm.

An apparatus for cutting into a subterranean formation includes a body and multiple cutting blades distributed around a circumference of the body. The cutting blades are configured to cut into the subterranean formation in response to being rotated. Each cutting blade includes a ball embedded in the respective cutting blade. At least a portion of the ball protrudes towards the subterranean formation from the respective cutting blade in which the ball is embedded. Each ball is configured to roll against the subterranean formation to reduce friction while the cutting blades are rotating.

Expandable reamers for enlarging a borehole in a subterranean formation include a tubular body, at least one curved blade track carried by the tubular body, and at least one blade engaged with the at least one blade track and configured to slide along the curved blade track along a curved path between a first retracted blade position and a second expanded blade position. To form such an expandable reamer, a tubular body having at least one curved blade track carried by the tubular body may be formed, and at least one blade may be engaged with the blade track. The blade and blade track may be configured such that the blade slides along the blade track along a curved path between a retracted position and an expanded position. Such expandable reamers may be used to enlarge boreholes in subterranean formations.

A method of hydraulically activating a mechanically operated wellbore tool in a bottom hole assembly includes: holding moveable elements of the wellbore tool in an unactivated position using a shear pin; inserting one or more drop balls into a drilling fluid; and flowing the drilling fluid with the drop balls to a flow orifice located in or below the wellbore tool. The flow orifice is at least partially plugged with the drop balls to restrict fluid flow and correspondingly increases the hydraulic pressure of the drilling fluid. The hydraulic pressure is increased to a point beyond the rating of the shear pin, thereby causing the shear pin to shear and allowing the moveable elements of the tool to move to an activated position.

Expandable reamers are configured to operate in a first, retracted state in which a plurality of blades is in a retracted position when a sliding sleeve is in a first sleeve position and a seat is in a first seat position, to operate in a second, extended state in which the plurality of blades is movable to an extended position when the sliding sleeve is in at least a second sleeve position and the seat is in the first seat position, and to operate in a third, retracted state in which the plurality of blades is returned to the retracted position when the sliding sleeve is in the at least a second position and the seat is in a second seat position.

An apparatus for cutting into a subterranean formation includes a body and multiple cutting blades distributed around a circumference of the body. The cutting blades are configured to cut into the subterranean formation in response to being rotated. Each cutting blade includes a ball embedded in the respective cutting blade. At least a portion of the ball protrudes towards the subterranean formation from the respective cutting blade in which the ball is embedded. Each ball is configured to roll against the subterranean formation to reduce friction while the cutting blades are rotating.

The present disclosure relates to an underreamer. In one aspect, the underreamer comprises a body, the body comprising at least one pocket therein, the underreamer further comprising at least one cutter secured with respect to the body, at least one actuating mechanism for moving the cutter between a retracted position in the pocket, and an extended position in which only the cutter projects from the body. In one aspect, the or each actuating mechanism comprises a piston for driving extension of the cutter, and a linkage to a cutter arm with respect to which the cutter is mounted, and a return spring for biasing the cutter to the retracted position.