Filtering acoustic waveforms in downhole environments

摘要

Methods and apparatus to filter acoustic waveforms in downhole environments are described. An example method involves receiving acoustic waveform data representing acoustic signals traversing at least a portion of a borehole adjacent a subterranean formation and performing a direct transform operation on the acoustic waveform data to generate wavelet map data. The wavelet map data comprises a time-frequency representation of the acoustic waveform data. The example method also involves identifying a waveform of interest via the wavelet map data, extracting data associated with the waveform of interest from the wavelet map data, generating filtered wavelet map data based on the extracted data, and performing an inverse transform operation on the filtered wavelet map data to generate filtered acoustic waveform data

主权项

1. A method, comprising:
receiving acoustic waveform data representing acoustic signals traversing at least a portion of a borehole adjacent a subterranean formation; performing a direct wavelet transform operation on the acoustic waveform data to generate first transformed data, the first transformed data comprising a time-frequency-domain representation of the acoustic waveform data; stacking the first transformed data to form a coherence data set; identifying a first wave component of interest via the coherence dataset, wherein the first wave component of interest is a casing arrival waveform; extracting second transformed data in the time-frequency domain associated with the first wave component; generating third transformed data in the time-frequency domain by removing the second transformed data from the first transformed data; and performing an inverse wavelet transform operation on the third transformed data in the time-frequency domain to generate filtered acoustic waveform data in time domain.