Drilling tool for sinking wells in underground rock formations
AssigneeBaker Hughes Incorporated
InventorsVolker Krueger, Hans-Juergen Faber, Dagobert Feld
Life of this patent
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Abstract
The present invention provides an apparatus for orienting a drilling tool in a borehole, and which employs drilling mud pressure to selectively hydraulically move force-transmitting elements associated with pressure members on the exterior of the tool against the wall of the borehole, or to radially shift the drive shaft of the drilling tool in the tool casing. The tool may also include a drilling mud powered centering mechanism for maintaining the tool or the drive shaft within the tool in a centered basic position. A tool may include both pressure members and a shiftable drive shaft, as well as centering mechanisms to act on both the pressure members and the drive shaft.
Claims32
A drilling tool for sinking wells in underground rock formations where the direction of drilling can be selected, comprising:
- a tubular outer casing that can be connected to a drill string by means of upper connecting means and which includes a drive shaft that rotates in the outer casing and has a rotary drill bit on the lower end thereof;
- a plurality of hydraulically actuated force-transmitting elements associated with hydraulic pressure chambers and arranged around the periphery of the outer casing for generating directional forces with radial force components for guiding the drilling tool;
- a control device for the force-transmitting elements including control valve means with drive means for the hydraulic actuation of each force-transmitting element, measured value sensors for position data on the drilling tool and a signal generator that generates control signals for the control valve drive means;
- and
- each hydraulic pressure chamber associated with a force-transmitting element being in selective communication with drilling mud of a higher pressure or drilling mud of a lower pressure through connecting channel means and the control valve assigned thereto.
Dependencies are inferred from the claim text.