System for controlled drilling of boreholes along planned profile
First Claim
1. A system for directional drilling of a borehole along a desired path with respect to a subterranean target, comprising:
- downhole means for three dimensional controlled drilling of a borehole along a planned path into said target, comprising;
a drill string;
a drill bit carried on said drill string;
means for rotating said drill bit;
downhole means for detecting the location of a subterranean target; and
means positioned in said borehole for receiving, storing and updating a planned path for said borehole;
a compliant subassembly in said drill string, said compliant subassembly comprising a portion of said drill string having a substantially greater known compliance than the other portions of said drill string, said compliant subassembly facilitating changes in the direction of drilling of said borehole;
sensing means for measuring strains in said compliant subassembly and for producing data signals corresponding to said strain measurements; and
means responsive to said data signals for changing the orientation of said drill bit in cooperation with movement of said compliant subassembly to change the direction of drilling of said borehole to correspond to said planned path for said borehole.
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Accused Products
Abstract
An improved method and apparatus for controlling the direction of advance of a rotary drill to produce a borehole profile substantially as preplanned with minimal curvature while maintaining optimum drilling performance. The preferred embodiment of the system comprises a drill string, a rotatable drill bit carried on said drill string, and a compliant subassembly in said drill string, said compliant subassembly facilitating changes in the direction of drilling of said borehole. The system further comprises a plurality of sensors for measuring strains within the compliant subassembly and for producing data signals corresponding to the strain measurements. A control system is operable to use the data signals to change the direction of the borehole by applying a shear force to the drill bit.
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Citations
15 Claims
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1. A system for directional drilling of a borehole along a desired path with respect to a subterranean target, comprising:
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downhole means for three dimensional controlled drilling of a borehole along a planned path into said target, comprising; a drill string; a drill bit carried on said drill string; means for rotating said drill bit; downhole means for detecting the location of a subterranean target; and means positioned in said borehole for receiving, storing and updating a planned path for said borehole; a compliant subassembly in said drill string, said compliant subassembly comprising a portion of said drill string having a substantially greater known compliance than the other portions of said drill string, said compliant subassembly facilitating changes in the direction of drilling of said borehole; sensing means for measuring strains in said compliant subassembly and for producing data signals corresponding to said strain measurements; and means responsive to said data signals for changing the orientation of said drill bit in cooperation with movement of said compliant subassembly to change the direction of drilling of said borehole to correspond to said planned path for said borehole. - View Dependent Claims (2, 3)
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4. A system for directional drilling of a borehole along a desired path with respect to a subterranean target, comprising:
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downhole means for three dimensional controlled drilling of a borehole along a planned path into said target, comprising; a drill string; a drill bit carried on said drill string; means for rotating said drill bit; downhole means for detecting the location of a subterranean target; and means positioned in said borehole for receiving, storing and updating a planned path for said borehole; a compliant subassembly in said drill string, said compliant subassembly having a portion of reduced diameter to facilitate measurement of mechanical strains therein, said portion of reduced diameter further having a substantially greater known compliance than the other portions of said drill string to allow said compliant subassembly to facilitate changes in the direction of drilling of said borehole; sensing means for measuring strains in said compliant subassembly and for producing data signals corresponding to said strain measurements; means for using said data signals corresponding to said strain measurements to calculate a shear force to cause said drill bit to follow a predetermined path; and means responsive to said data signals for changing the direction of said borehole by applying said shear force to said bit to cause said borehole to follow said planned path. - View Dependent Claims (5, 6, 7, 8, 9)
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11. A system for directional drilling of a borehole along a desired path with respect to a subterranean target, comprising:
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downhole means for three dimensional controlled drilling of a borehole along a planned path into said target, comprising; a drill string; a drill bit carried on said drill string; means for rotating said drill bit; downhole means for detecting the location of a subterranean target; and means positioned in said borehole for receiving, storing and updating a planned path for said borehole; a compliant subassembly in said drill string, said compliant subassembly having sufficient length and a greater known compliance than the other portions of said drill string to allow bending to change the direction of said borehole; sensing means for measuring strains in said compliant assembly and for producing data signals corresponding to said strain measurements; and means responsive to said data signals for changing the direction of said borehole by changing the axis of rotation of said bit, in cooperation with said compliant subassembly, to cause said borehole to follow said planned path. - View Dependent Claims (10, 12, 13, 14, 15)
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Specification