Joint time-variant spectral analysis — Part 2: A case study

Abstract

The joint time-frequency and time-phase analysis applied to a field seismic data highlights lateral changes on preferential frequency and phase illumination at the target across secondary faults. Mutual thin-bed interference modeling suited for the case study area was performed using a well-tying well-based extracted wavelet assumed to be representative of the wavelet embedded on the input seismic data. The long coda of this wavelet is also present on the corresponding thin-bed waveform, indicating the possibility of more complex mutual interference patterns between thin beds and mutual interference at farther vertical separations between thin beds compared with what would occur for an embedded wavelet with a shorter coda. The observed lateral changes on preferential frequency and phase illumination on the seismic data are attributable to collocated lateral changes in the stacking patterns and variable occurrence of vertically adjacent thin beds, which are interpreted as lateral sediment deposition changes induced by the syndepositional activity of the secondary faults. This is a geologic scenario that had not been previously considered on the area until the evidence of this case study provide indirect support for it.

Spectral Decomposition and a Waveform Cluster to Characterize Strongly Heterogeneous Paleokarst Reservoirs in the Tarim Basin, China

“…Spectral decomposition can be used to evaluate changes in bed thickness and lateral heterogeneity with higher resolution than the traditional quarter-wavelength theory [38]. Decomposing a seismic trace into time-variant frequency spectra allows us to draw inferences about seismic events in terms of layer thickness, rock properties, and stratification [39].…”