A bit for drilling a wellbore includes: a shank having a coupling formed at an upper end thereof; a body removably attached to a lower end of the shank and having a blade receptacle formed therethrough; a blade fixed to the body; a plurality of superhard cutters mounted along a leading edge of the fixed blade; a blade disposed in the blade receptacle and longitudinally movable relative to the body between an extended position and a retracted position; a plurality of superhard cutters mounted along a leading edge of the movable blade; and a spring disposed between the shank and the movable blade and biasing the movable blade toward the extended position.

A rotary cutting tool for use in a wellbore has an instrumented cutter fitted into a cavity in the tool body. The instrumented cutter body has an outer end portion exposed at the open end of a cavity and is connected to the tool body through at least one connecting section having a smaller cross-section and greater compliance than the outer end portion. The outer end portion and the connecting section are slightly movable within the cavity but the cavity surrounds at least part of the outer end portion sufficiently closely to limit transverse movement to elastic strain of the compliant connecting portion. One or more sensors, which may be strain gauges, are used to measure force on the outer end portion in a plurality of directions transverse to the cavity and causing elastic strain of the at least one connecting section.

A rotary cutting tool for use in a wellbore has an instrumented cutter fitted into a cavity in the tool body. The instrumented cutter body has an outer end portion exposed at the open end of a cavity and is connected to the tool body through at least one connecting section having a smaller cross-section and greater compliance than the outer end portion. The outer end portion and the connecting section are slightly movable within the cavity but the cavity surrounds at least part of the outer end portion sufficiently closely to limit transverse movement to elastic strain of the compliant connecting portion. One or more sensors, which may be strain gauges, are used to measure force on the outer end portion in a plurality of directions transverse to the cavity and causing elastic strain of the at least one connecting section.

A flow rate control system includes a housing and a valve assembly slidingly disposed within a housing inner bore. The housing includes bypass openings. The valve assembly includes a valve and an orifice disposed in a valve inner bore. The valve includes a plurality of valve bypass bores extending axially through a valve collar. The valve assembly slides between closed and fully open positions. A spring biases the valve assembly toward the closed position in which the valve closes the housing bypass openings. In the open position, a bypass fluid path is formed including the valve bypass bores and the housing bypass openings. The valve assembly is flow rate controlled in the closed position and pressure controlled in the open position. The valve assembly may slide within a sleeve assembly including sleeve bypass openings, which connect the valve bypass bores and housing bypass openings in the bypass fluid path.

An earth-boring tool includes a tool body configured to rotate in a wellbore and carrying at least one extendable element. The at least one extendable element is configured to move between a retracted position and an extended position projecting radially beyond the tool body. The at least one extendable element has a mating surface. The earth-boring tool includes a support structure located in the tool body and having a support surface that is located and configured to face the mating surface of the at least one extendable element when the at least one extendable element is in the extended position. The support surface of the support structure is configured to bear at least a portion of the tangential forces acting on the extendable element during rotation of the earth-boring tool in the wellbore when the at least one extendable element is in the extended position.

An earth-boring tool includes a tool body configured to rotate in a wellbore and carrying at least one extendable element. The at least one extendable element is configured to move between a retracted position and an extended position projecting radially beyond the tool body. The at least one extendable element has a mating surface. The earth-boring tool includes a support structure located in the tool body and having a support surface that is located and configured to face the mating surface of the at least one extendable element when the at least one extendable element is in the extended position. The support surface of the support structure is configured to bear at least a portion of the tangential forces acting on the extendable element during rotation of the earth-boring tool in the wellbore when the at least one extendable element is in the extended position.

A bit for drilling a wellbore includes: a shank having a coupling formed at an upper end thereof; a body removably attached to a lower end of the shank and having a blade receptacle formed therethrough; a blade fixed to the body; a plurality of superhard cutters mounted along a leading edge of the fixed blade; a blade disposed in the blade receptacle and longitudinally movable relative to the body between an extended position and a retracted position; a plurality of superhard cutters mounted along a leading edge of the movable blade; and a spring disposed between the shank and the movable blade and biasing the movable blade toward the extended position.

A hybrid bit includes an earth-boring element and a percussion element. The earth-boring element and the percussion element are coaxially arranged, with the earth-boring element surrounding the percussion element. A reciprocating member of the percussion element may oscillate in a manner that enables a bottom end of the reciprocating member to repeatedly protrude from a bottom end of the earth-boring element and to be repeatedly withdrawn. A configuration of the earth-boring element may enable it to drill into and remove some materials from an earth formation, while the percussion element may enable the hybrid bit to drill into and remove difficult-to-drill materials, including abrasive materials and/or materials with high compressive forces, such as chert.

A hybrid bit includes an earth-boring element and a percussion element. The earth-boring element and the percussion element are coaxially arranged, with the earth-boring element surrounding the percussion element. A reciprocating member of the percussion element may oscillate in a manner that enables a bottom end of the reciprocating member to repeatedly protrude from a bottom end of the earth-boring element and to be repeatedly withdrawn. A configuration of the earth-boring element may enable it to drill into and remove some materials from an earth formation, while the percussion element may enable the hybrid bit to drill into and remove difficult-to-drill materials, including abrasive materials and/or materials with high compressive forces, such as chert.

A tool for use in a wellbore includes a tubular body having a bore therethrough, an opening through a wall thereof, and a connector at each longitudinal end thereof; and an arm. The arm is pivotally connected to a first piston and rotationally coupled to the body, is disposed in the opening in a retracted position, and is movable to an extended position where an outer surface of the arm extends outward past an outer surface of the body. The first piston is disposed in the body bore, has a bore therethrough, and is operable to move the arm from the retracted position to the extended position in response to fluid pressure in the piston bore exceeding fluid pressure in the opening. The tool further includes a lock operable to retain the first piston in the retracted position; and a second piston operably coupled to the lock.