Abstract: A system and method for communicating with a downhole tool. A downhole tool includes a downlink receiver and a command actuator. The downlink receiver receives control information, encoded in rotation of the tool, that controls operation of the tool. The downlink receiver includes a rotation sensor and a decoder. The rotation sensor senses rotation of the tool about a longitudinal axis. The decoder demarcates fields of the control information based on rotation state transitions sensed by the rotation sensor. The rotation state transitions are transitions between a rotating state and a non-rotating state. The decoder also decodes a control value for controlling the tool based on a duration of a field of the control information. The control value is wholly encoded in the field, and the field is encoded as a non-rotating state of the tool. The command actuator applies the control value to control operation of the tool.

Abstract: A steerable drilling apparatus includes a control system inside a cylindrical housing connected to a drill bit having radially-extendable pistons. A fluid-metering assembly directs a piston actuating fluid into fluid channels in the drill bit leading to respective pistons. The control system controls the fluid-metering assembly to selectively allow fluid flow through the fluid channels to the pistons and to exit through orifices in the fluid channels. The selective fluid flow causes the actuated piston to temporarily extend in the opposite direction to a desired wellbore deviation, thereby deflecting the drill bit away from the borehole centerline. An upper member in the fluid-metering assembly can be moved to stabilize, steer, and change TFA within the drill bit. The control system and drill bit are connected so as to facilitate removal to change the drill bit's steering section and cutting structure configuration or gauge simultaneously.

Abstract: A downhole sensing assembly for sensing motor parameters of a downhole motor positionable in a wellbore penetrating a subterranean formation is provided. The downhole motor has a stator and a rotor rotatable within the stator. The sensing assembly includes at least one rotor extension operatively connectable to the rotor and movable therewith, at least one marker positionable about the rotor extension, and at least one motor sensor positionable about a downhole tool and operatively coupled to the marker to detect movement of the marker whereby motor parameters, such as rotational speed of the motor, are detectable.

Abstract: A system and method for communicating with a downhole tool. A downhole tool includes a downlink receiver and a command actuator. The downlink receiver receives control information, encoded in rotation of the tool, that controls operation of the tool. The downlink receiver includes a rotation sensor and a decoder. The rotation sensor senses rotation of the tool about a longitudinal axis. The decoder demarcates fields of the control information based on rotation state transitions sensed by the rotation sensor. The rotation state transitions are transitions between a rotating state and a non-rotating state. The decoder also decodes a control value for controlling the tool based on a duration of a field of the control information. The control value is wholly encoded in the field, and the field is encoded as a non-rotating state of the tool. The command actuator applies the control value to control operation of the tool.

Abstract: Apparatus and method for adjusting spring preloading in a downhole tool. In an apparatus, a mechanism includes a nut and a piston. The nut is configured to axially compress a spring in the downhole tool. The piston is coupled to the nut. Extension of the piston causes the nut to rotate and compress the spring. The nut is configured to maintain compression of the spring after the piston retracts.

Abstract: Apparatus and method for adjusting spring preloading in a downhole tool. In one embodiment, a mechanism includes a nut and a piston. The nut is configured to axially compress a spring in the downhole tool. The piston is coupled to the nut. Extension of the piston causes the nut to rotate and compress the spring. The nut is configured to maintain compression of the spring after the piston retracts.

Abstract: A steerable drilling apparatus includes a control system inside a cylindrical housing connected to a drill bit having radially-extendable pistons. A fluid-metering assembly directs a piston actuating fluid into fluid channels in the drill bit leading to respective pistons. The control system controls the fluid-metering assembly to selectively allow fluid flow through the fluid channels to the pistons and to exit through orifices in the fluid channels. The selective fluid flow causes the actuated piston to temporarily extend in the opposite direction to a desired wellbore deviation, thereby deflecting the drill bit away from the borehole centerline. An upper member in the fluid-metering assembly can be moved to stabilize, steer, and change TFA within the drill bit. The control system and drill bit are connected so as to facilitate removal to change the drill bit's steering section and cutting structure configuration or gauge simultaneously.