Downhole system with integrated backup sensors
First Claim
1. Apparatus for monitoring downhole conditions, the apparatus comprising:
- a first sensor operable to sense an environmental property;
a second sensor operable to sense the environmental property; and
a controller configured to;
obtain a first calibration sensor reading acquired by the first sensor at a first time;
obtain a second calibration sensor reading acquired by the second sensor at substantially the first time;
determine, based at least on the first and second calibration sensor readings, calibration information for the second sensor;
obtain a backup sensor reading acquired by the second sensor at a second time subsequent to the first time;
determine, based on the calibration information and the backup sensor reading a replacement sensor reading, the replacement sensor reading being an estimate of a sensor reading by the first sensor at the second time.
1 Assignment
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Accused Products
Abstract
A downhole system comprises a main sensor, such as a gamma sensor, and a backup sensor. The backup sensor may be of a different type from the main sensor. In some embodiments the backup sensor is a high reliability sensor that may have a different sensitivity from the main sensor. The system operates both the main and backup sensors and generates calibration data for the backup sensor. If the main sensor fails the calibration data may be applied to process data from the backup sensor to yield an estimate of the data that the main sensor would have yielded if it had remained operational. The calibration data may compensate for temperature variations and/or temporal drift, for example.
11 Citations
26 Claims
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1. Apparatus for monitoring downhole conditions, the apparatus comprising:
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a first sensor operable to sense an environmental property; a second sensor operable to sense the environmental property; and a controller configured to; obtain a first calibration sensor reading acquired by the first sensor at a first time; obtain a second calibration sensor reading acquired by the second sensor at substantially the first time; determine, based at least on the first and second calibration sensor readings, calibration information for the second sensor; obtain a backup sensor reading acquired by the second sensor at a second time subsequent to the first time; determine, based on the calibration information and the backup sensor reading a replacement sensor reading, the replacement sensor reading being an estimate of a sensor reading by the first sensor at the second time. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26)
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Specification