Abstract: Angular position readings are obtained during rotation of an apparatus in a borehole, and angular rate readings are obtained over time of the rotation. The angular rate readings are adjusted based at least on the angular position readings. The angular position measurement does not require calibrated magnetometers or accelerometers to function. Additionally, a dynamic scale factor calculation for an angular rate gyroscope (ARG) allows the ARG to be used over a much wider operating range than without such a calculation. Finally, an integrated angular rate from the ARG calibrated for bias and scale factor fills in positional information between the magnetometers' zero crossings to deliver a high resolution hybrid angular position system capable of measuring precise angular position at high and irregular downhole rotation rates.

Abstract: A fully rotating bias unit for directional drilling rotates at bit speed while providing proportional control of directional response and steering force. The unit also provides added reliability by having increased redundancy (multiple independently controlled actuators). The unit disposed on a drillstring transfers rotation to a drill bit and has a bore communicating fluid from the drillstring to the drill bit. Directors are disposed on the unit to rotate with it. Each of the directors is independently movable between extended and retracted conditions relative to the unit's housing. Actuators of the unit are in fluid communication between the bore and the borehole or some other low pressure. Each actuator is independently operable to direct communicated fluid from the bore to extend a respective one of the directors toward the extended condition.

Abstract: An apparatus is directed relative to geomagnetic and gravitational fields of reference while advancing with rotation in a borehole by determining angular position of the apparatus during the rotation and correcting the angular position of the apparatus relative to an offset of a toolface of the apparatus. To do the correction, a magnetic toolface of the apparatus during the rotation is determined based on geomagnetic readings of the apparatus in each of a plurality of divisions of the rotation relative to the geomagnetic field, and a gravitational toolface of the apparatus during the rotation is determined based on gravitational readings of the apparatus in each of the divisions of the rotation relative to the gravitational field. The offset of the toolface is then calculated as a difference between the magnetic toolface and the gravitational toolface. The corrected angular position can then be used in directing the apparatus.

Abstract: Angular position readings are obtained during rotation of an apparatus in a borehole, and angular rate readings are obtained over time of the rotation. The angular rate readings are adjusted based at least on the angular position readings. The angular position measurement does not require calibrated magnetometers or accelerometers to function. Additionally, a dynamic scale factor calculation for an angular rate gyroscope (ARG) allows the ARG to be used over a much wider operating range than without such a calculation. Finally, an integrated angular rate from the ARG calibrated for bias and scale factor fills in positional information between the magnetometers' zero crossings to deliver a high resolution hybrid angular position system capable of measuring precise angular position at high and irregular downhole rotation rates.

Abstract: A fully rotating bias unit for directional drilling rotates at bit speed while providing proportional control of directional response and steering force. The unit also provides added reliability by having increased redundancy (multiple independently controlled actuators). The unit disposed on a drillstring transfers rotation to a drill bit and has a bore communicating fluid from the drillstring to the drill bit. Directors are disposed on the unit to rotate with it. Each of the directors is independently movable between extended and retracted conditions relative to the unit's housing. Actuators of the unit are in fluid communication between the bore and the borehole or some other low pressure. Each actuator is independently operable to direct communicated fluid from the bore to extend a respective one of the directors toward the extended condition.

Abstract: Angular position readings are obtained during rotation of an apparatus in a borehole, and angular rate readings are obtained over time of the rotation. The angular rate readings are adjusted based at least on the angular position readings. The angular position measurement does not require calibrated magnetometers or accelerometers to function. Additionally, a dynamic scale factor calculation for an angular rate gyroscope (ARG) allows the ARG to be used over a much wider operating range than without such a calculation. Finally, an integrated angular rate from the ARG calibrated for bias and scale factor fills in positional information between the magnetometers' zero crossings to deliver a high resolution hybrid angular position system capable of measuring precise angular position at high and irregular downhole rotation rates.

Abstract: A fully rotating bias unit for directional drilling rotates at bit speed while providing proportional control of directional response and steering force. The unit also provides added reliability by having increased redundancy (multiple independently controlled actuators). The unit disposed on a drillstring transfers rotation to a drill bit and has a bore communicating fluid from the drillstring to the drill bit. Directors are disposed on the unit to rotate with it. Each of the directors is independently movable between extended and retracted conditions relative to the unit's housing. Actuators of the unit are in fluid communication between the bore and the borehole or some other low pressure. Each actuator is independently operable to direct communicated fluid from the bore to extend a respective one of the directors toward the extended condition.

Abstract: A drilling assembly disposed on a drillstring deviates a borehole (i.e., changes the trajectory of the borehole) advanced by a drill bit. A housing disposed on the drillstring transfers first rotation to the drill bit, and one or more directors are disposed on the housing to rotate therewith. Each of the directors is independently movable between an extended condition and a retracted condition relative to the housing. An actuator is disposed on the assembly and is operable provide a second rotation relative to the first rotation. An internal component is disposed in the housing and is rotatable by the second rotation of the actuator to have first and second conditions relative to each of the one or more directors rotating with the first rotation of the housing. The internal component in the first condition extends a given one of the one or more directors toward the extended condition.

Abstract: An apparatus is directed relative to geomagnetic and gravitational fields of reference while advancing with rotation in a borehole by determining angular position of the apparatus during the rotation and correcting the angular position of the apparatus relative to an offset of a toolface of the apparatus. To do the correction, a magnetic toolface of the apparatus during the rotation is determined based on geomagnetic readings of the apparatus in each of a plurality of divisions of the rotation relative to the geomagnetic field, and a gravitational toolface of the apparatus during the rotation is determined based on gravitational readings of the apparatus in each of the divisions of the rotation relative to the gravitational field. The offset of the toolface is then calculated as a difference between the magnetic toolface and the gravitational toolface. The corrected angular position can then be used in directing the apparatus.

Abstract: A drilling assembly disposed on a drillstring deviates a borehole (i.e., changes the trajectory of the borehole) advanced by a drill bit. A housing disposed on the drillstring transfers first rotation to the drill bit, and one or more directors are disposed on the housing to rotate therewith. Each of the directors is independently movable between an extended condition and a retracted condition relative to the housing. An actuator is disposed on the assembly and is operable provide a second rotation relative to the first rotation. An internal component is disposed in the housing and is rotatable by the second rotation of the actuator to have first and second conditions relative to each of the one or more directors rotating with the first rotation of the housing. The internal component in the first condition extends a given one of the one or more directors toward the extended condition.

Abstract: A fully rotating bias unit for directional drilling rotates at bit speed while providing proportional control of directional response and steering force. The unit also provides added reliability by having increased redundancy (multiple independently controlled actuators). The unit disposed on a drillstring transfers rotation to a drill bit and has a bore communicating fluid from the drillstring to the drill bit. Directors are disposed on the unit to rotate with it. Each of the directors is independently movable between extended and retracted conditions relative to the unit's housing. Actuators of the unit are in fluid communication between the bore and the borehole or some other low pressure. Each actuator is independently operable to direct communicated fluid from the bore to extend a respective one of the directors toward the extended condition.

Abstract: Angular position readings are obtained during rotation of an apparatus in a borehole, and angular rate readings are obtained over time of the rotation. The angular rate readings are adjusted based at least on the angular position readings. The angular position measurement does not require calibrated magnetometers or accelerometers to function. Additionally, a dynamic scale factor calculation for an angular rate gyroscope (ARG) allows the ARG to be used over a much wider operating range than without such a calculation. Finally, an integrated angular rate from the ARG calibrated for bias and scale factor fills in positional information between the magnetometers' zero crossings to deliver a high resolution hybrid angular position system capable of measuring precise angular position at high and irregular downhole rotation rates.