Reducing error contributions to gyroscopic measurements from a wellbore survey system
First Claim
1. A method of reducing gravity-dependent error contributions to gyroscopic measurements, the method comprising:
- providing a survey system within a portion of a wellbore, the survey system comprising;
a first gyroscopic sensor adapted to generate measurement signals indicative of at least one component of the Earth'"'"'s rotation substantially perpendicular to the portion of the wellbore; and
a second gyroscopic sensor adapted to generate measurement signals indicative of a component of the Earth'"'"'s rotation substantially parallel to the portion of the wellbore;
generating a first set of measurement signals indicative of the at least one component of the Earth'"'"'s rotation substantially perpendicular to the portion of the wellbore using the first gyroscopic sensor while the first gyroscopic sensor is in a corresponding first set of four orientations relative to the wellbore;
generating a second set of measurement signals indicative of the component of the Earth'"'"'s rotation substantially parallel to the portion of the wellbore using the second gyroscopic sensor while the second gyroscopic sensor is in a corresponding second set of four orientations relative to the wellbore;
calculating information regarding a measurement bias to the measurement signals from the first gyroscopic sensor using the measurement signals from the first gyroscopic sensor in two orientations of the first set of four orientations;
calculating information regarding a measurement bias to the measurement signals from the second gyroscopic sensor using the measurement signals from the second gyroscopic sensor in two orientations of the second set of four orientations;
calculating information regarding a quadrature bias to the measurement signals from the first gyroscopic sensor using the first set of measurement signals in the corresponding first set of four orientations; and
calculating information regarding a quadrature bias to the measurement signals from the second gyroscopic sensor using the second set of measurement signals in the corresponding second set of four orientations.
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Accused Products
Abstract
A method reduces error contributions to gyroscopic measurements from a wellbore survey system having two gyroscopic sensors adapted to generate signals indicative of at least one component of the Earth'"'"'s rotation substantially perpendicular to the wellbore and indicative of a component of the Earth'"'"'s rotation substantially parallel to the wellbore. The method includes generating a first signal indicative of the at least one substantially perpendicular component while the first sensor is in a first orientation; generating a second signal indicative of the at least one substantially perpendicular component while the first sensor is in a second orientation; generating a third signal indicative of the substantially parallel component while the second sensor is in a first orientation; and generating a fourth signal indicative of the substantially parallel component while the second sensor is in a second orientation. The method further includes calculating information regarding at least one of a mass unbalance offset error and a quadrature bias error using the first, second, third, and fourth signals.
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Citations
20 Claims
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1. A method of reducing gravity-dependent error contributions to gyroscopic measurements, the method comprising:
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providing a survey system within a portion of a wellbore, the survey system comprising; a first gyroscopic sensor adapted to generate measurement signals indicative of at least one component of the Earth'"'"'s rotation substantially perpendicular to the portion of the wellbore; and a second gyroscopic sensor adapted to generate measurement signals indicative of a component of the Earth'"'"'s rotation substantially parallel to the portion of the wellbore; generating a first set of measurement signals indicative of the at least one component of the Earth'"'"'s rotation substantially perpendicular to the portion of the wellbore using the first gyroscopic sensor while the first gyroscopic sensor is in a corresponding first set of four orientations relative to the wellbore; generating a second set of measurement signals indicative of the component of the Earth'"'"'s rotation substantially parallel to the portion of the wellbore using the second gyroscopic sensor while the second gyroscopic sensor is in a corresponding second set of four orientations relative to the wellbore; calculating information regarding a measurement bias to the measurement signals from the first gyroscopic sensor using the measurement signals from the first gyroscopic sensor in two orientations of the first set of four orientations; calculating information regarding a measurement bias to the measurement signals from the second gyroscopic sensor using the measurement signals from the second gyroscopic sensor in two orientations of the second set of four orientations; calculating information regarding a quadrature bias to the measurement signals from the first gyroscopic sensor using the first set of measurement signals in the corresponding first set of four orientations; and calculating information regarding a quadrature bias to the measurement signals from the second gyroscopic sensor using the second set of measurement signals in the corresponding second set of four orientations. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17)
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18. A computer system for reducing gravity-dependent error contributions to gyroscopic measurements made using a survey system within a portion of a wellbore, the survey system comprising a first gyroscopic sensor and a second gyroscopic sensor, the computer system comprising:
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means for controlling an orientation of the first gyroscopic sensor relative to the portion of a wellbore, the first gyroscopic sensor adapted to generate measurement signals indicative of at least one component of the Earth'"'"'s rotation substantially perpendicular to the portion of the wellbore; means for controlling an orientation of the second gyroscopic sensor relative to the portion of the wellbore, the second gyroscopic sensor adapted to generate measurement signals indicative of a component of the Earth'"'"'s rotation substantially parallel to the portion of the wellbore; means for receiving at least one measurement signal from the first gyroscopic sensor while the first gyroscopic sensor has a first orientation relative to the portion of the wellbore, at least one measurement signal from the first gyroscopic sensor while the first gyroscopic sensor has a second orientation relative to the portion of the wellbore, at least one measurement signal from the first gyroscopic sensor while the first gyroscopic sensor has a third orientation relative to the portion of the wellbore, and at least one measurement signal from the first gyroscopic sensor while the first gyroscopic sensor has a fourth orientation relative to the portion of the wellbore, the first, second, third, and fourth orientations different from one another; means for receiving at least one measurement signal from the second gyroscopic sensor while the second gyroscopic sensor has a first orientation relative to the portion of the wellbore, at least one measurement signal from the second gyroscopic sensor while the second gyroscopic sensor has a second orientation relative to the portion of the wellbore, at least one measurement signal from the second gyroscopic sensor while the second gyroscopic sensor has a third orientation relative to the portion of the wellbore, and at least one measurement signal from the second gyroscopic sensor while the second gyroscopic sensor has a fourth orientation relative to the portion of the wellbore, the first, second, third, and fourth orientations different from one another; means for calculating information regarding measurement biases to measurement signals from the first gyroscopic sensor and the second gyroscopic sensor using the measurement signals received from the first gyroscopic sensor in its first orientation and its second orientation and the measurement signals received from the second gyroscopic sensor in its first orientation and its second orientation; means for calculating information regarding a quadrature bias to the measurement signals from the first gyroscopic sensor using the measurement signals received from the first gyroscopic sensor in its first, second, third, and fourth orientations; and means for calculating information regarding a quadrature bias to the measurement signals from the second gyroscopic sensor using the measurement signals received from the second gyroscopic sensor in its first, second, third, and fourth orientations. - View Dependent Claims (19)
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20. A non-transitory computer-readable medium having instructions stored thereon which cause a general-purpose computer to perform a method for reducing gravity-dependent error contributions to gyroscopic measurements made using a survey system within a portion of a wellbore, the survey system comprising a first gyroscopic sensor and a second gyroscopic sensor, the method comprising:
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controlling an orientation of the first gyroscopic sensor relative to the portion of the wellbore, the first gyroscopic sensor adapted to generate measurement signals indicative of at least one component of the Earth'"'"'s rotation substantially perpendicular to the portion of the wellbore; controlling an orientation of the second gyroscopic sensor relative to the portion of the wellbore, the second gyroscopic sensor adapted to generate measurement signals indicative of a component of the Earth'"'"'s rotation substantially parallel to the portion of the wellbore; receiving at least one measurement signal from the first gyroscopic sensor while the first gyroscopic sensor has a first orientation relative to the survey system, at least one measurement signal from the first gyroscopic sensor while the first gyroscopic sensor has a second orientation relative to the survey system, at least one measurement signal from the first gyroscopic sensor while the first gyroscopic sensor has a third orientation relative to the survey system, at least one measurement signal from the first gyroscopic sensor while the first gyroscopic sensor has a fourth orientation relative to the survey system; receiving at least one measurement signal from the second gyroscopic sensor while the second gyroscopic sensor has a first orientation relative to the portion of the wellbore, at least one measurement signal from the second gyroscopic sensor while the second gyroscopic sensor has a second orientation relative to the portion of the wellbore, at least one measurement signal from the second gyroscopic sensor while the second gyroscopic sensor has a third orientation relative to the portion of the wellbore, at least one measurement signal from the second gyroscopic sensor while the second gyroscopic sensor has a fourth orientation relative to the portion of the wellbore; calculating information regarding a quadrature bias to the measurement signals from the first gyroscopic sensor using the measurement signals received from the first gyroscopic sensor in its first, second, third, and fourth orientations; and calculating information regarding a quadrature bias to the measurement signals from the second gyroscopic sensor using the measurement signals received from the second gyroscopic sensor using the measurement signals received from the second gyroscopic sensor in its first, second, third, and fourth orientations.
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Specification