This disclosure presents a downhole device configured as a selectable hole trimmer. The selectable hole trimmer comprises an upper sleeve affixed inside a body via a stop. A charge sleeve is slidable inside the upper sleeve to provide a pressure to a pressurized volume. A catch sleeve is slidable inside the charge sleeve to align a bypsss port and a return port with a drilling mud volume. An actuator is fluidly connected to the pressurized volume via a port. The actuator is configured to provide a pressure to a selectable hole cutter of the body via an actuation port in the transfer sleeve and actuate the selectable hole cutter piston of the selectable hole cutter to move relative to the body, wherein the cutter piston comprises one or more cutters. A manual controller configured to operate the actuator in response to a dropped activation ball.

A flushing system in a drill bit, which has a body that defines the flushing system, can include an inlet to facilitate supply of pressurized fluids into a bore hole. A cutting surface of the drill bit is provided with a main opening that defines a main passageway in communication with the inlet. A peripheral surface of the drill bit is provided with a secondary opening that defines a secondary passageway in communication with the inlet. The secondary passageway is disposed at an angle from a horizontal reference plane. The horizontal reference plane is defined between the inlet and the origin of the main passageway and is perpendicular to a central longitudinal axis of the body of the drill bit. An origin of the secondary passageway is at a distance from the origin of the main passageway.

A flushing system in a drill bit, which has a body that defines the flushing system, can include an inlet to facilitate supply of pressurized fluids into a bore hole. A cutting surface of the drill bit is provided with a main opening that defines a main passageway in communication with the inlet. A peripheral surface of the drill bit is provided with a secondary opening that defines a secondary passageway in communication with the inlet. The secondary passageway is disposed at an angle from a horizontal reference plane. The horizontal reference plane is defined between the inlet and the origin of the main passageway and is perpendicular to a central longitudinal axis of the body of the drill bit. An origin of the secondary passageway is at a distance from the origin of the main passageway.

A rotary steerable drill string (16) employs a drill bit (10) selected to positively contribute to underpressure in a preselected azimuthal segment of the borehole relative to an opposing azimuthal section. Generally, a high flow velocity of drilling fluid in the selected azimuthal segment relative to in other segments will result in a more pronounced underpressure in the selected azimuthal segment. Drill bit designs which locally enhance the drilling fluid flow velocity are proposed to be employed in the present rotary steerable drill string.

A rotary steerable drill string (16) employs a drill bit (10) selected to positively contribute to underpressure in a preselected azimuthal segment of the borehole relative to an opposing azimuthal section. Generally, a high flow velocity of drilling fluid in the selected azimuthal segment relative to in other segments will result in a more pronounced underpressure in the selected azimuthal segment. Drill bit designs which locally enhance the drilling fluid flow velocity are proposed to be employed in the present rotary steerable drill string.

A cutting element may include a fluid passage passing through the cutting element. The cutting element may further include a cutting edge and an aperture proximate the cutting edge. The aperture may be coupled to the fluid passage.

A cutting element may include a fluid passage passing through the cutting element. The cutting element may further include a cutting edge and an aperture proximate the cutting edge. The aperture may be coupled to the fluid passage.

A downhole tool activation assembly for prevention of activation from rig heave on a floating rig comprising a block release with a release feature. The release feature includes a release chamber, an activation chamber, and a fluid stop that retains a traveling block in a first position. A traveling block comprised of a plurality of drag blocks and drag block springs is configured to retain the traveling block to a position along an inner surface of a casing. The block release moves to a release position when the release feature is activated. The traveling block moves axially along a block mandrel with a block lug traveling within a j-slot. The j-slot on the block mandrel includes a run-in slot, a motion slot, and an activating slot configured to transfer the block lug to the next slot. The activating slot is configured to move the traveling block to an activating position.

A downhole tool activation assembly for prevention of activation from rig heave on a floating rig comprising a block release with a release feature. The release feature includes a release chamber, an activation chamber, and a fluid stop that retains a traveling block in a first position. A traveling block comprised of a plurality of drag blocks and drag block springs is configured to retain the traveling block to a position along an inner surface of a casing. The block release moves to a release position when the release feature is activated. The traveling block moves axially along a block mandrel with a block lug traveling within a j-slot. The j-slot on the block mandrel includes a run-in slot, a motion slot, and an activating slot configured to transfer the block lug to the next slot. The activating slot is configured to move the traveling block to an activating position.

Systems and methods for drilling a subterranean well with a drill bit include a drill bit body with a central bore. A plurality of ports extend through the nose end of the drill bit body from the central bore to an outside of the drill bit body. A blocked nozzle is located within one of the plurality of ports. The blocked nozzle has a nozzle bore end and a nozzle nose end opposite the nozzle bore end. A bore end disk is located at the nozzle bore end of the blocked nozzle, preventing a flow of fluids through the blocked nozzle past the bore end disk. A nose end disk is located at the nozzle nose end of the blocked nozzle, preventing the flow of fluids through the blocked nozzle past the nose end disk. The nose end disk and the bore end disk are removable.