Abstract: A drill bit for drilling a bore, the drill bit comprising: an outer housing; a primary cutting structure defining a cutting plane of a first diameter; a flow path arranged to let drilling fluid flow through the drill bit; and a deployable blade assembly at least partially located within the outer housing, the deployable blade assembly comprising a cutting structure and being arranged to be axially movable from a first position, in which the deployable cutting structure is recessed with respect to the primary cutting structure, towards the cutting plane, to a second position; wherein when the deployable blade assembly is in the second position, the deployable cutting structure defines a cutting diameter which is less than or equal to the first diameter.

Abstract: A drill bit for drilling a bore, the drill bit comprising: an outer housing; a primary cutting structure defining a cutting plane of a first diameter; a flow path arranged to let drilling fluid flow through the drill bit; and a deployable blade assembly at least partially located within the outer housing, the deployable blade assembly comprising a cutting structure and being arranged to be axially movable from a first position, in which the deployable cutting structure is recessed with respect to the primary cutting structure, towards the cutting plane, to a second position; wherein when the deployable blade assembly is in the second position, the deployable cutting structure defines a cutting diameter which is less than or equal to the first diameter.

Abstract: A selective downhole actuator comprising at least a first actuator position, a second actuator position and a third actuator position. The selective downhole actuator is reconfigurable between the first actuator position and the second actuator position. The selective actuator is selectively reconfigurable to the third actuator position by varying an operating parameter during a transition of the selective downhole actuator between the first and second actuator positions.

Abstract: A selective downhole actuator comprising at least a first actuator position, a second actuator position and a third actuator position. The selective downhole actuator is reconfigurable between the first actuator position and the second actuator position. The selective actuator is selectively reconfigurable to the third actuator position by varying an operating parameter during a transition of the selective downhole actuator between the first and second actuator positions.

Abstract: A drilling assembly assembly includes a hammer motor, a shaft, a driver, and a hammer (218). The shaft is operatively connectable to the hammer motor and rotated thereby. The driver is operatively connectable to the shaft, and includes a cam (such as guide channel 232) rotatable with the shaft and a fixed guide (such as guide pins 230) having a guide surface thereon. The cam is engageable with the guide surface and axially movable thereabout during rotation thereof. The hammer is operatively connectable to the driver and axially movable therewith, axially movable within the housing (215) independently from axial movement of the housing, and engageable with the bit to impart an impact thereto whereby the bit is hammered.

Abstract: A drilling assembly assembly includes a hammer motor, a shaft, a driver, and a hammer (218). The shaft is operatively connectable to the hammer motor and rotated thereby. The driver is operatively connectable to the shaft, and includes a cam (such as guide channel 232) rotatable with the shaft and a fixed guide (such as guide pins 230) having a guide surface thereon. The cam is engageable with the guide surface and axially movable thereabout during rotation thereof. The hammer is operatively connectable to the driver and axially movable therewith, axially movable within the housing (215) independently from axial movement of the housing, and engageable with the bit to impart an impact thereto whereby the bit is hammered.

Abstract: A downhole tool comprises a body defining a fluid inlet and two or more fluid outlets. A valve arrangement cycles the proportion of fluid directed from the inlet to each of the outlets. One of the outlets may be associated with a fluid pressure responsive device, such as a cleaning blade.