Optimizing thin‐bed interpretation with 90°‐phase wavelets

Abstract

Listen

Translate article

Different wavelet phases should be selected for different interpretation purposes. Neither zero phase nor 90° phase is universally better in all cases. For stratigraphic and lithologic interpretation of seismically thin beds, 90°‐phase wavelets have significant advantages. Seismic models of Ricker wavelets having selected phases are constructed to assess interpretability of composite waveforms in increasingly complex geologic settings. Zero‐phase seismic data are not optimal for interpretation of beds thinner than a wavelength (λ) because their antisymmetric thin‐bed responses tie to the reflectivity series, rather than impedance logs. The application of 90°‐phase data consistently improves seismic interpretability. The unique symmetry of 90°‐phase thin‐bed response eliminates the dual polarity of thin‐bed responses, resulting in better imagery of thin‐bed geometry, impedance profiles, lithology, and stratigraphy. Less amplitude distortion and less stratigraphy‐independent, thin‐bed interference lead to more accurate acoustic impedance estimation from amplitude data and a better tie of seismic traces to lithology‐indicative wireline logs. Field data applications support these observations.