Unequal illumination of the subsurface highly impacts the quality of seismic imaging. Different image points of the media have different folds of reflection-angle illumination, which can be caused by irregular acquisition or by wave propagation in complex media. To address this problem, we present a method of stacking angle-domain common-image gathers (ADCIGs), in which we use local similarity ...

Abstract The sharp increase in data size of the high-density and wide-azimuth seismic acquisition makes processing routines very challenging. To reduce turn-around time pre-stack migration (PSTM) for large-scale field (terra to petabyte size), we present an efficient wave-equation PSTM that is approximate version double-square-root (DSR) moderate lateral velocity variation. By converting DSR di...

Seismic imaging based on single-scattering approximation is based on analysis of the match between the source and receiver wavefields at every image location. Wavefields at depth are functions of space and time and are reconstructed from surface data either by integral methods (Kirchhoff migration) or by differential methods (reverse-time or wavefield extrapolation migration). Different methods...

Wavefield-extrapolation methods can produce angle-domain common-image gathers ADCIGs . To obtain ADCIGs for converted-wave seismic data, information about the image dip and the P-to-S velocity ratio must be included in the computation of angle gathers. These ADCIGs are a function of the half-aperture angle, i.e., the average between the incidence angle and the reflection angle. We have develope...

The estimation of a velocity model from seismic data is a crucial step for obtaining a high-quality image of the subsurface. Velocity estimation is usually formulated as an optimization problem where an objective function measures the mismatch between synthetic and recorded wavefields and its gradient is used to update the model. The objective function can be defined in the data-space (as in fu...

There are a variety of methods that can be used to extract rock-properties information from seismic data. Three of the methods that can be used, include; 1. AVO analysis, followed by post-stack inversion of the AVO attributes (Goodway, et al.) 2. Prestack inversion of the P-wave data directly to impedance (Hampson et al.) 3. Joint prestack inversion of the P-wave data and converted wave data di...

in seismic exploration studies different types of techniques are used to recognize seismic features in terms of their temporal and spatial spectra. variations in frequency content are sensitive to subtle changes in reflection information (castro de matos et al., 2003). in this study the joint time-frequency analysis is used for seismic texture recognition. discrete wavelet transform (dwt) witho...

Abstract With the development of seismic surveys and decline shallow petroleum resources, high resolution signal-to-noise ratio have become more important in processing. To improve quality data, stationary-phase migration based on dip-angle gathers can be used to separate reflected waves noise. However, this method is very computationally intensive heavily dependent expert experience. Neural ne...

Seismic data are often inadequately or irregularly sampled along spatial axes. Irregular sampling can produce artifacts in seismic imaging results. We present a new approach to interpolate aliased seismic data based on adaptive predictionerror filtering (PEF) and regularized nonstationary autoregression. Instead of cutting data into overlapping windows (patching), a popular method for handling ...

Common-image gathers are an important output of prestack depth migration. They provide information needed for velocity model building and amplitude and phase information for subsurface attribute interpretation. Conventionally, common-image gathers are computed using Kirchhoff migration on commonoffset/azimuth data volumes. When geologic structures are complex and strong contrasts exist in the v...