Stacking plays an important role in improving signal-to-noise ratio and imaging quality of seismic data. However, for low-fold-coverage seismic profiles, the result of conventional stacking is not always satisfactory. To address this problem, we have developed a method of stacking in which we use local correlation as a weight for stacking common-midpoint gathers after NMO processing or common-i...

Introduction If we assume that the correct migration algorithm has been used (see part I), errors in seismic images may still be present due to errors in the underlying velocity model. The standard way of detecting velocity errors is to search for misalignments in image gathers. However, the low signal-to-noise ratio of image gathers may make the analysis difficult. Image gathers from CFP gathe...

Imaging in complex media benefits from uniform illumination of the target from all possible directions. Moreover, it is desirable to recover reflectivity from seismic data as a function of incidence and azimuthal angles at every location over the reflector. Applications of angle-dependent reflectivity include velocity and anisotropy estimation and amplitude versus angle (AVA) analysis. One way ...

Migration of seismic reflection data to common image-point gathers is an integral part of both migration velocity analysis (MVA) and amplitude (AVA) analysis. Its applicability in complex geology depends on whether these gathers will be artifact free, and is related to the formation of caustics and turning ‘rays’ due to the heterogeneity of the velocity model used. Here, we discuss an angle tra...

velocity analysis is one of the most important step in seismic data processing. it affects not only many processing steps directly and indirectly, but also is known as a primary interpretation of the data. however, it can also be assumed as one of the most time consuming processing step. the conventional velocity analysis method measures the energy amplitude along hyperbolic trajectories within...

Abstract This article investigates bypassing the inversion steps involved in a standard litho-type classification pipeline and performing directly from imaged seismic data. We consider set of deep learning methods that map data into classes, trained on two variants synthetic data: (i) one which we image using local Radon transform to obtain angle gathers, (ii) another start subsurface-offset ba...

A multi-dimensional variable-length subband coder for prestack seismic data was presented. A 2and 3-D separable near perfect reconstruction filter bank was optimized to maximize the coding gain, assuming that the correlation properties of pre-stack seismic data can be modeled by directional dependent autoregressive processes. Identical quantization and entropy coder allocation strategies were u...

Hydrocarbon production modifies the stress conditions in the subsurface and changes the model parameters previously estimated from the prospect. The capability to remotely monitor the changes in the reservoir using seismic data has strategic importance since it allows us to infer fluid movement and evolution of stress conditions, which are key factors to enhance recovery and reduce uncertainty ...

The common-focus-point technology CFP describes prestack migration by focusing in two steps: emission and detection. The output of the first focusing step represents a CFP gather. This gather defines a shot record that represents the subsurface response resulting from a focused source wavefield. We propose applying the recursive shot-record, depthmigration algorithm to the CFP gathers of a seis...

An angle-dependent reflection coefficient is recovered by seismic migration in the angle domain. We have developed a postmigration technique for computing scattering and dip angle common-image gathers (CIGs) from seismic images, extended by the subsurface offset, based on wave-equation migration methods. Our methodology suggests a system of Radon transform operators by introducing local transfo...