Downhole surveying utilizing multiple measurements
First Claim
1. A drill string, comprising:
- a downhole portion adapted to move within a wellbore, the downhole portion hag a first portion at a first position within the wellbore and oriented at a first angle relative to the wellbore at the first position and a second portion at a second position within the wellbore and oriented at a second angle relative to the wellbore at the second position, wherein at least one of the first and second angles is non-zero;
a first acceleration sensor mounted within the first portion, the first acceleration sensor adapted to generate a first signal indicative of an acceleration of the first acceleration sensor; and
a second acceleration sensor mounted within the second portion, the second acceleration sensor adapted to generate a second signal indicative of an acceleration of the second acceleration sensor, wherein a difference between the first angle and the second angle is due to gravity induced sag and is less than about one degree.
1 Assignment
0 Petitions
Accused Products
Abstract
Certain embodiments described herein provide a measure of the misalignment of multiple acceleration sensors mounted in the downhole portion of a drill string. In certain embodiments, the measure of the misalignment corresponds to a measure of sag which can be used to provide an improved estimate of the inclination of the downhole portion of the drill string and/or the wellbore. Certain embodiments described herein provide an estimate of the magnetic interference incident upon a drilling system using multiple magnetic sensors mounted within a non-magnetic region of the downhole portion of the drilling system. Certain embodiments utilize the magnetic measurements to determine an axial interference resulting from one or more magnetic portions of the downhole portion and to provide an improved estimate of the azimuthal orientation of the downhole portion with respect to the magnetic field of the Earth.
149 Citations
39 Claims
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1. A drill string, comprising:
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a downhole portion adapted to move within a wellbore, the downhole portion hag a first portion at a first position within the wellbore and oriented at a first angle relative to the wellbore at the first position and a second portion at a second position within the wellbore and oriented at a second angle relative to the wellbore at the second position, wherein at least one of the first and second angles is non-zero; a first acceleration sensor mounted within the first portion, the first acceleration sensor adapted to generate a first signal indicative of an acceleration of the first acceleration sensor; and a second acceleration sensor mounted within the second portion, the second acceleration sensor adapted to generate a second signal indicative of an acceleration of the second acceleration sensor, wherein a difference between the first angle and the second angle is due to gravity induced sag and is less than about one degree. - View Dependent Claims (27, 28)
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2. A drill string, comprising:
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a downhole portion adapted to move within a wellbore, the downhole portion having a first portion at a first position within the wellbore and oriented at a first angle relative to the wellbore at the first position and a second portion at a second position within the wellbore and oriented at a second angle relative to the wellbore at the second position, wherein at least one of the first and second angles is non-zero; a first acceleration sensor mounted within the first portion, the first acceleration sensor adapted to generate a first signal indicative of an acceleration of the first acceleration sensor; a second acceleration sensor mounted within the second portion, the second acceleration sensor adapted to generate a second signal indicative of an acceleration of the second acceleration sensor; and a controller configured to calculate the difference between the first angle and the second angle. - View Dependent Claims (4, 5, 6, 7, 8, 9, 33, 34, 35, 36, 37, 38)
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3. A drill string, comprising:
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a downhole portion adapted to move within a wellbore, the downhole portion having a first portion at a first position within the wellbore and oriented at a first angle relative to the wellbore at the first position and a second portion at a second position within the wellbore and oriented at a second angle relative to the wellbore at the second position, wherein at least one of the first and second angles is non-zero; a first acceleration sensor mounted within the first portion, the first acceleration sensor adapted to generate a first signal indicative of an acceleration of the first acceleration sensor; and a second acceleration sensor mounted within the second portion, the second acceleration sensor adapted to generate a second signal indicative of an acceleration of the second acceleration sensor, wherein the first and second acceleration sensors are spaced apart from one another by a distance in a range between about 40 feet to about 70 feet. - View Dependent Claims (29, 30, 31, 32)
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10. A method for generating information indicative of misalignment between first and second acceleration sensors mounted within the downhole portion of a drill string, the method comprising:
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providing a drill string comprising; a downhole portion adapted to move within a wellbore, the downhole portion having a first portion at a first position within the wellbore and oriented at a first angle relative to the wellbore at the first position and a second portion at a second position within the wellbore and oriented at a second angle relative to the wellbore at the second position wherein at least one of the first and second angles is non-zero; a first acceleration sensor mounted within the first portion, the first acceleration sensor adapted to generate a first signal indicative of an acceleration of the first acceleration sensor; and a second acceleration sensor mounted within the second portion, the second acceleration sensor adapted to generate a second signal indicative of an acceleration of the second acceleration sensor; generating the first signal and the second signal while the downhole portion of the drill string is within the wellbore; and calculating the difference between the first angle and the second angle. - View Dependent Claims (11, 12, 13)
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14. A method of determining the misalignment between first and second acceleration sensors mounted within a drill string, the method comprising:
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receiving one or more acceleration measurements from a first acceleration sensor in a first portion of the drill string at a first position within a wellbore, the first portion oriented at a first angle relative the wellbore at the first position; receiving one or more acceleration measurements from a second acceleration sensor in a second portion of the drill string at a second position within the wellbore, the second portion oriented at a second angle relative to the wellbore at the second position, wherein at least one of the first and second angles is non-zero; and calculating the difference between the first angle and the second angle in response to the one or more acceleration measurements from the first acceleration sensor and the one or more measurements from the second acceleration sensor. - View Dependent Claims (39)
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15. A drilling system, comprising:
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a downhole portion adapted to move along a first wellbore, the downhole portion comprising one or more magnetic regions and one or more non-magnetic regions; at least two magnetic sensors within at least one non-magnetic region of the downhole portion, the at least two magnetic sensors comprising a first magnetic sensor and a second magnetic sensor spaced apart from one another by a non-zero distance, the first magnetic sensor adapted to generate a first signal in response to magnetic fields of the Earth and of the one or more magnetic regions, the second magnetic sensor adapted to generate a second signal in response to magnetic fields of the Earth and of the one or more magnetic regions; and a controller configured to receive the first signal and the second signal and to calculate the magnetic field of the one or more magnetic regions. - View Dependent Claims (16, 17, 18, 19, 20)
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21. A method for generating information indicative of the magnetic field in a first wellbore, the method comprising:
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providing a drilling system comprising; a downhole portion adapted to move along a first wellbore, the downhole portion comprising one or more magnetic regions and one or more non-magnetic regions; and at least two magnetic sensors within at least one non-magnetic region of the downhole portion, the at least two magnetic sensors comprising a first magnetic sensor and a second magnetic sensor spaced apart from one another by a non-zero distance, the first magnetic sensor adapted to generate a first signal in response to magnetic fields of the Earth and of the one or more magnetic regions, the second magnetic sensor adapted to generate a second signal in response to magnetic fields of the Earth and of the one or more magnetic regions; generating the first signal and the second signal while the downhole portion of the drilling system is at a first location within the first wellbore; and calculating the magnetic field in the first wellbore in response to the first and second signals. - View Dependent Claims (22, 23)
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24. A method for determining the magnetic field in a wellbore, the method comprising:
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receiving one or more magnetic measurements from at least two magnetic sensors within at least one non-magnetic region of a downhole portion of a drilling system, the at least two magnetic sensors comprising a first magnetic sensor and a second magnetic sensor spaced apart from one another by a non-zero distance, the first magnetic sensor generating a first signal in response to magnetic fields of the Earth and of one or more magnetic regions of the downhole portion, the second magnetic sensor generating a second signal in response to magnetic fields of the Earth and of the one or more magnetic regions; and calculating the magnetic field in response to the one or more magnetic measurements from the at least two magnetic sensors. - View Dependent Claims (25, 26)
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Specification