System for drilling deviated boreholes
First Claim
1. A method of drilling a borehole through earth formations with a drill string including a rotary bit at the lower end thereof, and obtaining information regarding a downhole parameter indicative of the borehole or the earth formations, the bit being powered by a drill motor within the drill string and including a power assembly of the drill motor for converting pressurized fluid to rotation of a mandrel interconnected with the bit, a bearing assembly between the power assembly and the bit for guiding the mandrel, and a bearing housing for housing the bearing assembly, the method comprising:
- sensing the downhole parameter using a sensor fixedly located in the drill string at a location axially below the power assembly;
transmitting signals functionally related to the sensed downhole parameter from a location axially below the power assembly;
receiving the transmitted signals at the surface to determine the downhole parameter; and
altering the drilling trajectory in response to the transmitted signals.
1 Assignment
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Accused Products
Abstract
Improved techniques are provided for drilling a deviated borehole through earth formations utilizing a rotary bit powered by a drill motor, and for obtaining information regarding the borehole or earth formations while drilling. An inclinometer is positioned below the drill motor and within a sealed cavity of a housing fixed to a drill motor sub, and a transmitter within the sealed cavity forwards acoustic or radial wave signals to a receiver provided in a measurement-while-drilling tool. The MWD tool may be provided within a non-magnetic portion of the drill string, and further houses an accelerometer for sensing borehole direction. Both borehole inclination and directional signals are transmitted to the surface by the MWD tool, and the drilling trajectory is altered in response to the signals.
159 Citations
20 Claims
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1. A method of drilling a borehole through earth formations with a drill string including a rotary bit at the lower end thereof, and obtaining information regarding a downhole parameter indicative of the borehole or the earth formations, the bit being powered by a drill motor within the drill string and including a power assembly of the drill motor for converting pressurized fluid to rotation of a mandrel interconnected with the bit, a bearing assembly between the power assembly and the bit for guiding the mandrel, and a bearing housing for housing the bearing assembly, the method comprising:
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sensing the downhole parameter using a sensor fixedly located in the drill string at a location axially below the power assembly; transmitting signals functionally related to the sensed downhole parameter from a location axially below the power assembly; receiving the transmitted signals at the surface to determine the downhole parameter; and altering the drilling trajectory in response to the transmitted signals. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10)
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11. The method of drilling a deviated borehole through earth formations with a drill string including a rotary bit at the end thereof and obtaining information regarding a downhole parameter indicative of the borehole or the earth formations, the bit being powered by a drill motor within the drill string and including a power assembly for converting pressurized fluid to rotation of a mandrel interconnected with the bit, and a bearing assembly between the power assembly and the bit for guiding the mandrel, the method comprising:
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monitoring borehole or earth formation characteristics using a sensor fixedly located in the drill string at a location axially below the power assembly; transmitting signals functionally related to the monitored information from the location axially below the power assembly; receiving the transmitted signals at the surface to determine the borehole or formation characteristic; and altering the drilling trajectory in response to the transmitted signals. - View Dependent Claims (12, 13, 14)
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15. A system for drilling a deviated borehole through earth formations, including a drill string including a drill bit, the bit powered by a drill motor having a power assembly for converting pressurized fluid to rotation of a mandrel interconnected with the bit, a bearing assembly between the power assembly and the bit for guiding the mandrel, and a bearing housing for housing the bearing assembly, the system comprising:
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a sealed cavity within the drill string at a location below the power assembly; a sensor within the sealed cavity for sensing a downhole parameter; a transmitter within the cavity for transmitting signals functionally related to the sensed downhole parameter; and a receiver spaced axially above the drill motor for receiving the transmitted signals and outputting downhole parameter signals. - View Dependent Claims (16, 17, 18, 19, 20)
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Specification