Relative and Absolute Error Models for Subterranean Wells
First Claim
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1. A method for determining a relative uncertainty between a first location on a first well and a corresponding second location on a second well, the method comprising:
- (a) acquiring inter-well ranging data;
(b) causing a processor to process the ranging data acquired in (a) to obtain a separation between the first and second locations; and
(c) causing the processor to process at least one of the separation obtained in (b) and the ranging data acquired in (a) to obtain the relative uncertainty between the first and second locations.
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Abstract
A relative error model is used to compute a relative uncertainty in the position of a first well with respect to a second well. This relative uncertainty may be computed in real time during drilling and may be used in making subsequent steering decisions during drilling. Moreover, an absolute uncertainty in the position of a first well may be obtained by combining an absolute uncertainty in the position of a second well and the relative uncertainty in the position of the first well with respect to the second well.
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Citations
37 Claims
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1. A method for determining a relative uncertainty between a first location on a first well and a corresponding second location on a second well, the method comprising:
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(a) acquiring inter-well ranging data; (b) causing a processor to process the ranging data acquired in (a) to obtain a separation between the first and second locations; and (c) causing the processor to process at least one of the separation obtained in (b) and the ranging data acquired in (a) to obtain the relative uncertainty between the first and second locations. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13)
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14. A method of well planning comprising:
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(a) acquiring a relative error model that relates an uncertainty in a relative position on a first well with respect to a second well; (b) computing a relative uncertainty of the position on the first well with respect to the second well using the relative error model acquired in (a) and a predetermined separation between the first well and the second well; and (c) using the error model acquired in (a) and the uncertainty computed in (b) to plan a well path for the first well with respect to the second well.
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15. A method for determining an absolute uncertainty of at least one location on a well, the method comprising:
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(a) acquiring an absolute uncertainty of a first location on a first well; (b) computing a relative uncertainty of a second location on a second well with respect to the first location on the first well, the second location being within sensory range of the first location; and (c) combining the absolute uncertainty of the first location on the first well acquired in (a) with the relative uncertainty of the second location on the second well computed in (b) to obtain an absolute uncertainty of the second location on the second well. - View Dependent Claims (16, 17, 18, 19, 20)
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21. A method for determining an absolute uncertainty in a second well path, the method comprising:
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(a) acquiring absolute uncertainties of at least a first location on a first well and at least a second location on a second well using an absolute error model, the first and second locations being within sensory range of one another; (b) computing a relative uncertainty between the first location and the second location using a relative error model; (c) computing modified parameters for the absolute error model used to acquire the absolute uncertainties in (a) from the absolute uncertainty of the first location acquired in (a) and the relative uncertainty computed in (b); (d) computing absolute uncertainties at selected other locations on the second well using the modified parameters computed in (c). - View Dependent Claims (22, 23, 24, 25, 26, 27, 28)
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29. A method for determining an absolute uncertainty of at least one location on a well path, the method comprising:
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(a) drilling first and second wells to within sensory range of one another; (b) measuring a separation between at least a first location on the first well and at least a second location on the second well; (c) computing a relative uncertainty in the separation; (d) computing absolute uncertainties of at least the first and second locations using an absolute error model; (e) combining the absolute uncertainty of the first location computed in (d) with the relative uncertainty computed in (c) to obtain an alternative absolute uncertainty of the second location. - View Dependent Claims (30, 31, 32, 33, 34, 35, 36)
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37. A method for determining an absolute uncertainty of a well, the method comprising:
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(a) sensing one well from another well; (b) transferring an absolute uncertainty of one of the wells to the other of the wells; and (c) recalculating an absolute uncertainty of at least one of the wells using the absolute uncertainty of the other of the wells.
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Specification