Automatic adjustment of magnetostrictive transducer preload for acoustic telemetry in a wellbore
First Claim
1. A magnetostrictive transducer system comprising:
- a magnetostrictive transducer mechanically coupled to a tubular member, the magnetostrictive transducer arranged to strain in response to a drive signal and thereby produce a corresponding acoustic wave in the tubular member;
a preload spring positioned between and in contact with the tubular member and the magnetostrictive transducer to apply a preload force on the magnetostrictive transducer;
an oscillator positioned to receive a carrier signal and to drive a reference signal that is proportional to the received carrier signal;
a filter module positioned to receive the reference signal, to filter the carrier signal, and to provide a filtered carrier signal to the magnetostrictive transducer, where the filtered carrier signal is a first component of the drive signal;
a detector module positioned to receive the reference signal and an output signal and to provide a corrective DC signal as a feedback to the magnetostrictive transducer, where the corrective DC signal is a second component of the drive signal, for automatic adjustment to the strain of the magnetostrictive transducer; and
an acoustic telemetry receiver mechanically coupled to the tubular member to sense acoustic waves in the tubular member and to transduce corresponding electrical signals to provide the output signal to the detector module.
1 Assignment
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Accused Products
Abstract
A magnetostrictive transducer system included as part of a drill string for use downhole in a well to convey signals across regions of the drill string that preclude the use of wired communication elements. The magnetostrictive transducer conveys a carrier signal as an acoustic wave through a drill collar region to an acoustic telemetry receiver, which passes an output both to an uphole processing system and back into the magnetostrictive transducer system. The output signal and carrier signal are compared to determine sub-harmonics or higher order harmonics of the output or carrier signal indicative of offset in the magnetostrictive core of the magnetostrictive transducer system, and provides a corrective component signal to automatically adjust the magnetostrictive core though preloading forces.
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Citations
22 Claims
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1. A magnetostrictive transducer system comprising:
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a magnetostrictive transducer mechanically coupled to a tubular member, the magnetostrictive transducer arranged to strain in response to a drive signal and thereby produce a corresponding acoustic wave in the tubular member; a preload spring positioned between and in contact with the tubular member and the magnetostrictive transducer to apply a preload force on the magnetostrictive transducer; an oscillator positioned to receive a carrier signal and to drive a reference signal that is proportional to the received carrier signal; a filter module positioned to receive the reference signal, to filter the carrier signal, and to provide a filtered carrier signal to the magnetostrictive transducer, where the filtered carrier signal is a first component of the drive signal; a detector module positioned to receive the reference signal and an output signal and to provide a corrective DC signal as a feedback to the magnetostrictive transducer, where the corrective DC signal is a second component of the drive signal, for automatic adjustment to the strain of the magnetostrictive transducer; and an acoustic telemetry receiver mechanically coupled to the tubular member to sense acoustic waves in the tubular member and to transduce corresponding electrical signals to provide the output signal to the detector module. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16)
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17. A method of transducing a signal through a tubular member comprising:
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setting a working point for a magnetostrictive core mechanically coupled to the tubular member; collecting and filtering a carrier signal to generate a filtered carrier signal; combining the filtered carrier signal with a corrective signal to generate a drive signal; delivering the drive signal to the magnetostrictive core, causing the magnetostrictive core to change in length and generate an acoustic signal in the tubular member; and receiving the acoustic signal with a telemetry receiver, the telemetry receiver providing an output signal and a feedback to automatically adjust the corrective signal. - View Dependent Claims (18, 19, 20, 21, 22)
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Specification