Automated Single-Channel Data Inversion Using Diffractions
B. Schwarz, A. Bauer and D. Gajewski
Event name: 79th EAGE Conference and Exhibition 2017
Session: Diffraction Modelling and Imaging
Publication date: 12 June 2017
Info: Extended abstract, PDF ( 1.77Mb )
Price: € 20
Large source-receiver offset acquisition offers the benefits of high data redundancy and improved illumination. However, large-offset recordings are generally expensive to acquire and the vast majority of academic research deals with a low channel count and target depths that significantly exceed the available offset range. Diffractions provide superior illumination compared to reflections, but typically have low amplitudes. We present a scheme that specifically targets the weak but highly illuminating diffracted background through automated adaptive subtraction of the dominant reflected contributions, while making only use of the available near-offset channel. Based on local stacking and coherence evaluation, the recorded diffracted events are treated as passive source wavefields, which are characterized in terms of local properties of wavefronts emerging at the registration surface. In an industrial field data example offshore Israel, where large offsets were available, we show that the diffraction-based wavefront inversion of only the near-offset channel leads to results, which are in reasonable agreement with available geological interpretations. By application to an academic low-fold dataset recorded near Santorini in the Aegean Sea, we demonstrate that the suggested inversion scheme offers the opportunity to construct laterally resolved depth-velocity models even in the actual absence of large-offset recordings.