Apparatus and method for automated drilling of a borehole in a subsurface formation
First Claim
1. A method for automated drilling of a borehole in a subsurface formation, comprising:
- selecting at least one control variable;
defining a drilling performance objective having a value that is influenced by drilling of the borehole using the at least one control variable;
drilling a first interval of the borehole maintaining the at least one control variable at a first value;
drilling a second interval of the borehole maintaining the at least one control variable at a second value; and
drilling a third interval of the borehole maintaining the at least one control variable at a third value, the third value being selected by applying an offset to one of the first value and the second value, a direction of the offset selected based on a comparison of the value of the drilling performance objective while drilling the first interval and the value of the drilling performance objective while drilling the second interval to a predetermined optimal value of the drilling performance objective;
selecting, for each of the first, second, and third interval, the value of the at least one control variable by applying a near search offset value to the value of the at least one control variable applied for a previously drilled interval;
determining whether the value of the drilling performance objective has changed over the first second and third intervals;
drilling a fourth interval of the borehole, andselecting, responsive to the determining, for the fourth interval of the borehole, a value of the at least one control variable by applying a far search offset value to the value of the at least one control variable based on the drilling performance objective not having changed over the first, second, and third intervals of the borehole;
wherein a magnitude of the far search offset value is greater than a magnitude of the near search offset value.
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Accused Products
Abstract
Apparatus and method for automated drilling of a borehole in a subsurface formation. In one embodiment, a method includes selecting at least one control variable. A drilling performance objective having a value that is influenced by drilling of the borehole using the at least one control variable is defined. A first interval of the borehole is drilled maintaining the at least one control variable at a first value. A second interval of the borehole is drilled maintaining the at least one control variable at a second value. A third interval of the borehole is drilled maintaining the at least one control variable at a third value. The third value is selected based on a comparison of the values of the drilling performance objective while drilling the first interval and second interval to a predetermined optimal value of the drilling performance objective.
27 Citations
21 Claims
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1. A method for automated drilling of a borehole in a subsurface formation, comprising:
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selecting at least one control variable; defining a drilling performance objective having a value that is influenced by drilling of the borehole using the at least one control variable; drilling a first interval of the borehole maintaining the at least one control variable at a first value; drilling a second interval of the borehole maintaining the at least one control variable at a second value; and drilling a third interval of the borehole maintaining the at least one control variable at a third value, the third value being selected by applying an offset to one of the first value and the second value, a direction of the offset selected based on a comparison of the value of the drilling performance objective while drilling the first interval and the value of the drilling performance objective while drilling the second interval to a predetermined optimal value of the drilling performance objective; selecting, for each of the first, second, and third interval, the value of the at least one control variable by applying a near search offset value to the value of the at least one control variable applied for a previously drilled interval; determining whether the value of the drilling performance objective has changed over the first second and third intervals; drilling a fourth interval of the borehole, and selecting, responsive to the determining, for the fourth interval of the borehole, a value of the at least one control variable by applying a far search offset value to the value of the at least one control variable based on the drilling performance objective not having changed over the first, second, and third intervals of the borehole; wherein a magnitude of the far search offset value is greater than a magnitude of the near search offset value. - View Dependent Claims (2, 3, 4, 5, 6, 7)
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8. An apparatus for automated drilling of a borehole in a subsurface formation, comprising:
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a drill sting for drilling the borehole, the drill sting controlled by a set of control variables; sensors for measuring a plurality of drilling variables during drilling of the borehole; a drilling performance optimizer configured to; evaluate, based on at least one of the drilling variables, a drilling performance objective having a value that is influenced by drilling of the borehole using the set of control variables; and select an operative set of values for the set of control variables by applying an offset to one of a first and second set of values of the control variables previously applied in drilling the borehole; and select a direction of the offset based on a comparison of values of a drilling performance objective produced by drilling with each of the first and second set of values to a predetermined optimal value of the drilling performance objective; monitor the value of the drilling performance objective over drilling of more than three successive intervals of the borehole; apply different sets of values for the set of control variables to each interval; adjust each of the different sets of values by applying a near search offset; determine whether the value of the drilling performance objective has changed over the more than three successive intervals; and generate a far search set of values for the set of control variables by applying a far search offset value based on the drilling performance objective not having changed over the more than three successive intervals of the borehole; wherein a magnitude of the far search offset value is greater than a magnitude of the near search offset value. - View Dependent Claims (9, 10, 11, 12, 13, 14)
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15. A non-transitory computer-readable medium encoded with computer-executable instructions for automated drilling of a borehole in a subsurface formation, when executed the computer-executable instructions cause a processor to:
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control drilling of a first interval of the borehole using a set of control variables populated with a set of first values; determine a first value of a drilling performance objective corresponding to drilling of the first interval of the borehole; control drilling of a second interval of the borehole using the set of control variables populated with a set of second values; determine a second value of the drilling performance objective corresponding to drilling of the second interval of the borehole; and control drilling of a third interval of the borehole using the set of control variables populated with a set of third values selected by applying an offset to one of the first set of values and the second set of values, a direction of the offset selected based on a determination of which of the first and second values of the drilling performance objective is closest to a predetermined optimal value of the drilling performance objective; generate the values of the set of control variables applied while drilling each of the first, second and third intervals by applying a near search offset value to a previously used set of values, wherein the set of control variables is populated with a different set of values for each of the first, second, and third intervals; determine whether the value of the drilling performance objective has changed over the first, second and third intervals; generate a far search set of values for the set of control variables by applying a far search offset value to a previously used set of values based on the drilling performance objective not having changed over the first, second and third intervals of the borehole; and control drilling on a fourth interval of the borehole using the set of control variables populated with the far search set of values; wherein a magnitude of the far search offset value is greater than a magnitude of the near search offset value. - View Dependent Claims (16, 17, 18, 19, 20, 21)
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Specification