Diffraction imaging method using the pattern operator in migrated dip-angle gathers

Abstract

Diffracted wavefield carries high-resolution information about subwavelength geological structural elements crucial for imaging small-scale subsurface discontinuities. However, the presence of strong reflection often obscures weak diffraction, limiting the effective use of diffraction in depicting detailed small-scale structures. To obtain a high-resolution diffraction image, we present a novel two-phase diffraction separation method that combines pattern-based method and energy attenuation function of stationary reflection in migrated dip angle gathers. In the first phase, the pattern-based method utilizes pattern operator to characterize non-stationary features of reflection in dip angle gathers and effectively eliminates the reflection outside the stationary point. In the second phase, the energy attenuation function based on dip angle is used to further attenuate residual reflection near the stationary point. The conflicting dip angles often reduces the performance of dip-based energy attenuation methods. We introduce the covariance rate criterion to adaptively adjust the conflicting dip angle, so that the energy attenuation function can more accurately attenuate the residual reflection. The numerical experiment conducted on classic Sigsbee2B model validates the efficacy of the proposed method in suppressing strong high-slope reflection while preserving details of small-scale faults and scatterers. The real data application demonstrates the performance of the method to highlight deep fractures, presenting additional potential reservoir-related structural insights.