Communications – electrical: acoustic wave systems and devices – Seismic prospecting – Land-reflection type
Patent
1993-12-20
1997-01-14
Moskowitz, Nelson
Communications, electrical: acoustic wave systems and devices
Seismic prospecting
Land-reflection type
367 25, 367 43, 367 45, 367 74, 364422, G01V 140
Patent
active
055947069
ABSTRACT:
Methods for processing sonic logging data obtained by a sonic imaging tool or an MWD tool are provided. The sonic logging data are bandpass filtered and sampled according to techniques such as integer band decimation, quadrature modulation, and single side band modulation to provide compressed signals which can be reconstructed if desired. The compressed signals are alternatively stored for downloading and further processing, sent uphole for processing, or processed downhole. The processing preferably involves processing the analytic portion of the compressed signals according to an improved semblance processing technique where the semblance function is calculated over a time window utilizing coarse slowness and time sampling steps. The slowness and time sampling steps are dictated by the parameters of the bandpass filter and the inter-receiver spacing of the tool. The waveform for each receiver is preferably interpolated based on the time step size to provide those data points necessary for stacking. From the determined semblance peaks, or interpolation thereabout, the formation slowness is derived.
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Chang Shu-Kong
Shenoy Ramachandra
Gordon David P.
Hyden Martin D.
Moskowitz Nelson
Schlumberger Technology Corporation
Smith Keith G. W.
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