Diffractor localization via weighted Radon transforms

Boulder Detection in the Shallow Sub‐Seafloor by Diffraction Imaging With Beamforming on Ultra‐High Resolution Seismic Data—A Feasibility Study

“…As proposed by for example, Nowak and Imhof (2004) the product of the semblance and the stack is calculated to obtain the weighted stack (Figure 6h). The weighted stack shows an improved resolution and a decreased relative amplitude of multiple energy which is characterized by a lower semblance than the diffraction (Figure 6g).…”

“…Mathematically, this beamforming approach is a discrete Radon transform. The Semblance Weighted Radon transform B (TWT d ,0 , v rms ) in seismics is the integral along a particular trajectory of the seismic data D ( x , TWT d ) at offset d (Nowak & Imhof, 2004) weighted with the semblance S (TWT d ,0 , v rms ) of the form presented in Ng and Perz (2004) and Cao and Bancroft (2005): $$$B\left({\text{TWT}}_{d,0},{v}_{rms}\right)=\,S\left({\text{TWT}}_{d,0},{v}_{\text{rms}}\right)\int D\left(d,{\text{TWT}}_{d}\right)\delta x$$$ …”

“…As diffractions are up to two orders of magnitude weaker than reflections (Khaidukov et al., 2004), and thus difficult to detect within high‐amplitude reflection energy, a number of dedicated diffraction imaging techniques utilize reflection‐suppression methods such as Radon transforms (Bansal & Imhof, 2016), eigenvector filters (Bansal & Imhof, 2016; Guigné et al., 2014), plane‐wave deconstruction filters (Fomel et al., 2007; Ford et al., 2021), or adaptive subtraction (Khaidukov et al., 2004; Preine et al., 2020; Schwarz, 2019; Schwarz & Gajewski, 2017; Schwarz & Krawczyk, 2020). After suppression, the diffractions can be imaged via migration (Bachrach & Reshef, 2016; Ford et al., 2021; Preine et al., 2020), Radon transforms (Karimpouli et al., 2015; Nowak & Imhof, 2004), or beamforming (Guigné et al., 2014).…”

Diffraction Enhancement Through Pre-Image Processing: Applications to Field Data, Sarawak Basin, East Malaysia

“…Diffraction imaging is a high-resolution imaging technology specifically designed to image and identify the small-scale fault in shale and carbonate reservoirs that are responsible for the increase in natural fracture density [1]. The diffraction volume can be used to complement structural images produced by the reflection imaging [1][2][3][4][5][6]. The diffraction oscillation pattern can still be observed if the reflection horizon terminates for a reason other than faulting.…”

“…A numerical model of offset recorded wave propagation suggests that the fractures may resemble diffractions. Diffraction data can be enhanced by removing the primary and multiple from the reflection seismic data [5]. Native scatterers embedded in a uniform medium produce a hyperbolic coda of wavelets where the apex of these hyperbolas coincides with the location of the scatterer on common shot gather data.…”