Televiewer image wood-grain reduction techniques
AssigneeBaker Hughes Incorporated
InventorsRoger R. Steinsiek, Jason M. Harris, Jinsong Zhao, Douglas J. Patterson, James B. Domnanish
Life of this patent
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Abstract
Measurements made by a transducer assembly for downhole imaging are affected by reverberations between the transducer and the window on the outside of the assembly. The reverberations result in a stationary noise on the image. Hardware solutions to improve signal-to-noise ratio includes using a composite transducer, adjusting the distance between the transducer and the window. SNR can also be improved by processing techniques that include stacking, fitting a sinusoid to the reverberation, by envelope peak detection, and by applying a notch filter.
Claims18
An apparatus configured to evaluate an earth formation from acoustic signals propagated into a borehole, the apparatus comprising:
- a transducer configured to produce a signal including a ringdown signal and an echo from a wall of the borehole from a plurality of orientations;
- and
- at least one processor configured to adjust the signal produced for each of the plurality of orientations using an estimation of the ringdown signal to increase a signal-to-noise ratio associated with the signal and use the adjusted signal to provide a two-dimensional image of the earth formation such that the two-dimensional image is substantially free of a stationary noise resulting from an interference between the ringdown signal and the echo.
A method of evaluating an earth formation, the method comprising:
- conveying a transducer into a borehole;
- using the transducer to produce a signal including a ringdown signal and an echo from a wall of the borehole from a plurality of orientations;
- and
- adjusting the signal produced for each of the plurality of orientations using an estimation of the ringdown signal to increase a signal-to-noise ratio associated with the signal and using the adjusted signal to provide a two-dimensional image of the earth formation such that the two-dimensional image is substantially free of a stationary noise resulting from interference between the ringdown signal and the echo.
A non-transitory computer-readable medium product having stored thereon instructions that when executed by at least one processor, cause the at least one processor to perform a method, the method comprising:
- adjusting a signal produced by a transducer in a borehole, the signal including a ringdown signal and an echo from a wall of the borehole from a plurality of orientations, the adjusting using an estimation of the ringdown signal to increase a signal-to-noise ratio associated with the signal, and using the adjusted signal to provide a two-dimensional image of the earth formation such that the two-dimensional image is substantially free of a stationary noise resulting from interference between the ringdown signal and the echo.
Dependencies are inferred from the claim text.