Embodiments of a downhole drilling assembly generally include a rotatable lower drilling assembly, a rotatable upper drilling assembly, and a drill bit, wherein the upper drilling assembly contains a mud motor adapted for clockwise rotation of its stator and counter-clockwise rotation of its rotor, whereby the lower drilling assembly is rotatable in the opposite direction of the upper drilling assembly or maintainable in a non-rotating state. The apparatus further includes sensors adapted to continuously measure physical properties and/or drilling parameters and a mechanism for continuously transmitting information relating thereto to the surface.

Embodiments of a method for operating a downhole drilling assembly generally include continuously measuring physical properties and/or drilling parameters proximate the drill bit, continuously transmitting information relating thereto to the surface, and controlling rotation of a lower drilling assembly in a non-rotating state or in the opposite direction of an upper drilling assembly by varying drill string rotation.

Embodiments of a downhole drilling assembly generally include a rotatable lower drilling assembly, a rotatable upper drilling assembly, and a drill bit, wherein the upper drilling assembly contains a mud motor adapted for clockwise rotation of its stator and counter-clockwise rotation of its rotor, whereby the lower drilling assembly is rotatable in the opposite direction of the upper drilling assembly or maintainable in a non-rotating state. The apparatus further includes sensors adapted to continuously measure physical properties and/or drilling parameters and a mechanism for continuously transmitting information relating thereto to the surface.

Embodiments of a method for operating a downhole drilling assembly generally include continuously measuring physical properties and/or drilling parameters proximate the drill bit, continuously transmitting information relating thereto to the surface, and controlling rotation of a lower drilling assembly in a non-rotating state or in the opposite direction of an upper drilling assembly by varying drill string rotation.

A method for drilling a subterranean wellbore includes rotating a drill string in the subterranean wellbore to drill the wellbore. The drill string includes a rotary steerable tool or a steerable drill bit including at least first and second axially spaced pads configured to extend radially outward from a tool body and engage a wall of the wellbore. Radial displacements of each of the first and second axially spaced pads are measured while drilling. The measured radial displacements are processed to compute a rate of penetration of drilling.

A method for drilling a subterranean wellbore includes rotating a drill string in the subterranean wellbore to drill the wellbore. The drill string includes a rotary steerable tool or a steerable drill bit including at least first and second axially spaced pads configured to extend radially outward from a tool body and engage a wall of the wellbore. Radial displacements of each of the first and second axially spaced pads are measured while drilling. The measured radial displacements are processed to compute a rate of penetration of drilling.

A boring tool is movable through the ground. A transmitter supported by the boring tool transmits an electromagnetic homing signal. A portable device monitors the electromagnetic homing signal and receives the electromagnetic homing signal in a homing mode for guiding the boring tool to a target position. A processor generates steering commands for guiding the boring tool based on a bore plan in a steering mode such that at least some positional error is introduced without using the electromagnetic homing signal. Switching from the steering mode to the homing mode is based on monitoring of the electromagnetic homing signal as the boring tool approaches the portable device to then guide the boring tool to the target position location in compensation for the positional error. Intermediate target positions are described as well as guiding the boring tool based on the homing signal so long as the portable device receives the signal.

A boring tool is movable through the ground. A transmitter supported by the boring tool transmits an electromagnetic homing signal. A portable device monitors the electromagnetic homing signal and receives the electromagnetic homing signal in a homing mode for guiding the boring tool to a target position. A processor generates steering commands for guiding the boring tool based on a bore plan in a steering mode such that at least some positional error is introduced without using the electromagnetic homing signal. Switching from the steering mode to the homing mode is based on monitoring of the electromagnetic homing signal as the boring tool approaches the portable device to then guide the boring tool to the target position location in compensation for the positional error. Intermediate target positions are described as well as guiding the boring tool based on the homing signal so long as the portable device receives the signal.

A method includes providing a Bottom Hole Assembly (BHA) in a wellbore. The BHA includes a rotary steerable system and a downhole attitude correction and control system. The downhole correction and control system includes a first sensor set, the sensors of the first sensor set positioned near ferromagnetic components of a drill string and a second sensor set, the sensors of the second sensor set positioned further from the ferromagnetic components of the drill string than the sensors of the first sensor set. Corrupted data from the first sensor set and reference data from the second sensor set is obtained, the corrupted data including cross-axis magnetometer and accelerometer measurements. The method additionally includes correcting the corrupted sensor data to form corrected sensor measurements and calculating an estimated azimuth from the corrected sensor measurements. The method further includes steering the rotary steerable system based on the estimated azimuth.

A method includes providing a Bottom Hole Assembly (BHA) in a wellbore. The BHA includes a rotary steerable system and a downhole attitude correction and control system. The downhole correction and control system includes a first sensor set, the sensors of the first sensor set positioned near ferromagnetic components of a drill string and a second sensor set, the sensors of the second sensor set positioned further from the ferromagnetic components of the drill string than the sensors of the first sensor set. Corrupted data from the first sensor set and reference data from the second sensor set is obtained, the corrupted data including cross-axis magnetometer and accelerometer measurements. The method additionally includes correcting the corrupted sensor data to form corrected sensor measurements and calculating an estimated azimuth from the corrected sensor measurements. The method further includes steering the rotary steerable system based on the estimated azimuth.

In a manual/automatic non-electric-connection borehole clinometer for a landslide, a clinometer probe completes borehole inclination measurement; a hoisting mechanism is connected to the clinometer probe by a pull rope; and a first tooth disc of an automatic clutch and a first tooth disc of a manual clutch are fixed to a left shaft end and a right shaft end of the hoisting mechanism respectively, a second tooth disc of the automatic clutch is fixed to a driving shaft of an electric driving mechanism and selectively meshes with or moves away from the first tooth disc of the automatic clutch, and a second tooth disc of the manual clutch is fixed to a driving shaft of a manual driving mechanism and selectively meshes with or moves away from the first tooth disc of the manual clutch.

A housing defines a through passage along its length and is configured to support a group of electrical isolators surrounding the through passage to form an electrically isolating break in a drill string such that each isolator of the group of isolators is subject to no more than a compressive force responsive to extension and retraction of the drill string. The housing defines a housing cavity to receive an electronics package having a signal port and is configured for electrical connection of the signal port across the electrically isolating break. A housing lid can cooperate with a main housing body to define elongated slots for purposes of enhancing the emanation of a locating signal. A housing arrangement can support electrical connections from an electronics package to bridge an electrically isolating gap.