Inspiration for Seismic Diffraction Modelling, Separation, and Velocity in Depth Imaging

Abstract

Fractured imaging is an important target for oil and gas exploration, as these images are heterogeneous and have contain low-impedance contrast, which indicate the complexity in a geological structure. These small-scale discontinuities, such as fractures and faults, present themselves in seismic data in the form of diffracted waves. Generally, seismic data contain both reflected and diffracted events because of the physical phenomena in the subsurface and due to the recording system. Seismic diffractions are produced once the acoustic impedance contrast appears, including faults, fractures, channels, rough edges of structures, and karst sections. In this study, a double square root (DSR) equation is used for modeling of the diffraction hyperbola with different velocities and depths of point diffraction to elaborate the diffraction hyperbolic pattern. Further, we study the diffraction separation methods and the effects of the velocity analysis methods (semblance vs. hybrid travel time) for velocity model building for imaging. As a proof of concept, we apply our research work on a steep dipping fault model, which demonstrates the possibility of separating seismic diffractions using dip frequency filtering (DFF) in the frequency–wavenumber (F-K) domain. The imaging is performed using two different velocity models, namely the semblance and hybrid travel time (HTT) analysis methods. The HTT method provides the optimum results for imaging of complex structures and imaging below shadow zones.

RETRACTED ARTICLE: Improvement of seismic data quality and recognition of fault discontinuities through seismic data conditioning applications: a case study of Issaran oil field, Gulf of Suez, Egypt

“…Truncated horizons Issaran field is affected by complex structuration (normal faults), which results in seismic velocity differences at structural element locations. Moreover, at their terminations, these structural features yield diffraction noises and seismic wave scattering (Jaglan et al 2015;Bashir et al 2020) and anhydrite cement to spread laterally and vertically within the Issaran field's reservoir layers. As a result, the seismic waves were scattered and dispersed, resulting in a low signal-to-noise ratio and spatial resolution of Issaran seismic data (Sarhan, 2017;Bouchaala et al, 2018;Rao and Wang, 2019).…”

Seismic Interpretation and Inversion Leading to an Accurate Reservoir Characterization in a Carbonate Environment

“…These two horizons were selected to apply the seismic inversion within the reservoir. The acoustic impedance log is calculated by multiplying the sonic and density log in well location [2][3][4]. In a seismic inversion, the most signifi cant…”

Seabed morphology characterization for Indonesian cable-based tsunameter route in Cilacap Segment, Indonesia

“…Wave diffraction on the research trajectory is present as a pseudo-reflector that is hyperbolic like paying. Such wave diffraction may indicate the presence of field discontinuities such as faults, fracturing, salt diapirs, or large rock blocks in the geometry of subsurface reflectors [22].…”