Abstract: An apparatus disposed on a drillstring deviates a borehole advanced by a drill bit. At least one director is disposed on a housing to rotate therewith. The director at least includes a piston movable in a chamber, a pad pivotable about a pivot point between an extended condition and a retracted condition relative to the housing, and a linkage arm pivotably connected between the piston and the pad. At least one actuator disposed on the housing in fluid communication with a housing bore is operable at least between a first condition (directing communicated fluid from the bore or other source to the chamber of the director) and a second condition (at least permitting the director to retract toward the retracted condition).

Abstract: A rotary steerable tool used for directional drilling include a housing, at least one external director, and at least one valve. The external director is hydraulically movable to an extended condition relative to the housing, and the valve selectively directs pressurized fluid from a first side of the valve to the external director on the valve's second side. A first seal of the valve is selectively orientable about an axis and has an inlet, which communicates with the pressurized fluid from the first side. A second seal of the valve disposed adjacent the first seal has an outlet, which communicates the pressurized fluid to the second side at least when aligned with the inlet. A bearing assembly of the valve is disposed at the axis between the seals and has male and female bearing surfaces, which are angled off the axis and are mated with one another.

Abstract: A rotary steerable tool used for directional drilling include a housing, at least one external director, and at least one valve. The external director is hydraulically movable to an extended condition relative to the housing, and the valve selectively directs pressurized fluid from a first side of the valve to the external director on the valve's second side. A first seal of the valve is selectively orientable about an axis and has an inlet, which communicates with the pressurized fluid from the first side. A second seal of the valve disposed adjacent the first seal has an outlet, which communicates the pressurized fluid to the second side at least when aligned with the inlet. A bearing assembly of the valve is disposed at the axis between the seals and has male and female bearing surfaces, which are angled off the axis and are mated with one another.

Abstract: An apparatus is disposed on a drillstring for deviating a borehole advanced by a drill bit. The assembly includes a housing, at least one director, and at least one actuator. The housing is disposed on the drillstring and transfers rotation to the drill bit. The housing has a bore communicating fluid from the drillstring to the drill bit. The at least one director is disposed on the housing to rotate therewith. The at least one director at least includes a piston movable in a chamber, a pad pivotable about a pivot point between an extended condition and a retracted condition relative to the housing, and a linkage arm pivotably connected between the piston and the pad. The at least one actuator is disposed on the housing in fluid communication with the bore.

Abstract: Disclosed herein is a system for steering the direction of a borehole advanced by cutting action of a rotary drill bit by periodically varying action of a drill bit while continuously rotating a drill string to which the drill bit is operationally attached. The steering system can include a bit perturbation device cooperating with a bent housing subsection and operationally connected to the drill string and to the drill bit. Drill bit action can be varied by periodically varying the rotation speed and/or rate of penetration of the drill bit. Periodic drill bit action results in preferential cutting of material from a predetermined arc of the borehole wall which, in turn, results in borehole deviation. Action of the drill bit can be varied independently of the rotation rate of the drill string.

Abstract: Apparatus and methods for removing the effects of directional drilling systems drilling fluid pulses to allow a MWD mud pulse telemetry system to operate without interference. The methodology is based upon Synchronous Time Averaging (STA). With STA, any pressure fluctuation that is cyclical (or synchronous) with a measurable event can be profiled and subsequently subtracted from a mud pulse telemetry signal. STA functions by placing a strobe in such a manner that the strobe is triggered for each cyclical event. The cyclical event in this disclosure is one (or more) revolution(s) of the drill string. If there is a pressure fluctuation that correlates to that cyclical event, it will be identified by a stable profile of that pressure fluctuation. This pressure profile is then used to remove the cyclical pressure fluctuation from the input mud pulse telemetry signal thereby allowing normal operation of the mud pulse telemetry system.

Abstract: Disclosed herein is a system for steering the direction of a borehole advanced by cutting action of a rotary drill bit by periodically varying action of a drill bit while continuously rotating a drill string to which the drill bit is operationally attached. The steering system can include a bit perturbation device cooperating with a bent housing subsection and operationally connected to the drill string and to the drill bit. Drill bit action can be varied by periodically varying the rotation speed and/or rate of penetration of the drill bit. Periodic drill bit action results in preferential cutting of material from a predetermined arc of the borehole wall which, in turn, results in borehole deviation. Action of the drill bit can be varied independently of the rotation rate of the drill string.

Abstract: Disclosed herein is a system for steering the direction of a borehole advanced by cutting action of a rotary drill bit by periodically varying action of a drill bit while continuously rotating a drill string to which the drill bit is operationally attached. The steering system can include a bit perturbation device cooperating with a bent housing subsection and operationally connected to the drill string and to the drill bit. Drill bit action can be varied by periodically varying the rotation speed and/or rate of penetration of the drill bit. Periodic drill bit action results in preferential cutting of material from a predetermined arc of the borehole wall which, in turn, results in borehole deviation. Action of the drill bit can be varied independently of the rotation rate of the drill string.

Abstract: A system for steering the direction of a borehole advanced by cutting action of a rotary drill bit by periodically varying the rotation speed of the drill bit. The steering system comprises a motor disposed in a bent housing subsection and operationally connected to a drill string and to the drill bit. The rotation speed of the drill bit is periodically varied by periodic varying the rotation speed of the motor or by periodic varying the rotation speed of the drill string. Periodic bit speed rotation results in preferential cutting of material from a predetermined arc of the borehole wall which, in turn, resulting in borehole deviation. Both the drill string and the drill motor are rotated simultaneously during straight and deviated borehole drilling.

Abstract: A system for steering the direction of a borehole advanced by cutting action of a rotary drill bit by periodically varying the rotation speed of the drill bit. The steering system comprises a motor disposed in a bent housing subsection and operationally connected to a drill string and to the drill bit. The rotation speed of the drill bit is periodically varied by periodic varying the rotation speed of the motor or by periodic varying the rotation speed of the drill string. Periodic bit speed rotation results in preferential cutting of material from a predetermined arc of the borehole wall which, in turn, resulting in borehole deviation. Both the drill string and the drill motor are rotated simultaneously during straight and deviated borehole drilling.

Abstract: A system for steering the direction of a borehole advanced by cutting action of a rotary drill bit by periodically varying action of a drill bit while continuously rotating a drill string to which the drill bit is operationally attached. The steering system comprises a bit perturbation device cooperating with a bent housing subsection and operationally connected to the drill string and to the drill bit. Drill bit action is varied by periodic varying the rotation speed or rate of penetration of the drill bit. Periodic drill bit action results in preferential cutting of material from a predetermined arc of the borehole wall which, in turn, resulting in borehole deviation.

Abstract: Methods and apparatus for determining the direction of borehole azimuthal offset and the borehole radius of curvature. Rotation rate of a borehole assembly is measured and mathematically converted into azimuthal torque imparted to the borehole assembly. Relative azimuthal offset is determined from variations in azimuthal torque over a rotation cycle of the borehole assembly. Relative radius of curvature is obtained from the magnitude of azimuthal torque over a rotation cycle. Relative azimuthal offset is converted to true azimuthal offset using an independent reference angle measurement. Relative borehole curvature is converted to true radius of curvature using a calibration constant determined in known borehole conditions.

Abstract: Methods and apparatus for determining the direction of borehole azimuthal offset and the borehole radius of curvature. Rotation rate of a borehole assembly is measured and mathematically converted into azimuthal torque imparted to the borehole assembly. Relative azimuthal offset is determined from variations in azimuthal torque over a rotation cycle of the borehole assembly. Relative radius of curvature is obtained from the magnitude of azimuthal torque over a rotation cycle. Relative azimuthal offset is converted to true azimuthal offset using an independent reference angle measurement. Relative borehole curvature is converted to true radius of curvature using a calibration constant determined in known borehole conditions.

Abstract: A system for steering the direction of a borehole advanced by cutting action of a rotary drill bit by periodically varying the rotation speed of the drill bit. The steering system comprises a motor disposed in a bent housing subsection and operationally connected to a drill string and to the drill bit. The rotation speed of the drill bit is periodically varied by periodic varying the rotation speed of the motor or by periodic varying the rotation speed of the drill string. Periodic bit speed rotation results in preferential cutting of material from a predetermined arc of the borehole wall which, in turn, resulting in borehole deviation. Both the drill string and the drill motor are rotated simultaneously during straight and deviated borehole drilling.