​ADF(R) Images KH by Imaging Seismic Dispersion in the Frequency Domain

KH from Seismic

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Circa 1975, the industry made a simplification by assuming that all seismic frequencies have the same velocity.  Frequency dependent velocity (“dispersion”), was believed to occur, but only at high frequencies.  Apex has brought to light that in fact permeability causes large velocity variations with frequency – inside the seismic bandwidth.

Dispersion results in frequency dependent reflection coefficients.  The result of frequency dependent reflection coefficients is spectral compression in the frequency domain, which is stretch in the time domain.  However, seismic data is replete with tuning effects and these tuning effects also cause frequency domain compression/time domain stretch.  What makes ADF(R) special is it's ability to effectively remove tuning effects before measuring frequency domain compression/stretch, which is then a measure of KH.  Effectively doing this was the hard part of inventing and commercializing ADF(R).  This process took well over a decade develop, hone and make stable and robust.

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