One way of developing a wave-equation approach to seismic imaging is based on the concept of downward continuation of the surface reflection data. Seismic imaging is typically based on the single scattering approximation, and assumes the knowledge of a, smooth, background model in which the mentioned downward continuation is carried out. The downward continued data are subjected, at each depth,...

Prestack depth migration of shot profiles by downward continuation is a practical imaging algorithm that is especially cost-effective for sparse-shot wide-azimuth geometries. The interpretation of offset as the displacement between the downward-propagating (shot) wavefield and upward-propagating (receiver) wavefield enables us to extract offset-domain common imagepoint (CIP) gathers during shot...

Estimating an accurate velocity model is crucial for seismic imaging to obtain a good understanding of the subsurface structure. The objective of this thesis is to investigate methods of velocity analysis by optimizing seismic images. A conventional seismic image is obtained by zero-lag crosscorrelation of wavefields extrapolated from a source wavelet and recorded data on the surface using a ve...

Worldwide interest in shale plays has rapidly increased in recently years, thanks to the combination of horizontal drilling and hydraulic fracturing. Shale formations act as both the source and the reservoir for the natural gas and usually exhibit anisotropic properties at larger scale. Geological and petropysical studies found that the right combination of thickness, TOC (total organic carbon)...

Estimating an accurate velocity model is crucial for seismic imaging to obtain a good understanding of the subsurface structure. The objective of this thesis is to investigate methods of velocity analysis by optimizing seismic images. A conventional seismic image is obtained by zero-lag crosscorrelation of wavefields extrapolated from a source wavelet and recorded data on the surface using a ve...

As multicomponent (3C or 4C) seismic acquisitions are now commonly used, specific processings for multicomponent datasets are required. The aim of this paper is to present a new wavefield filter for multicomponent seismic data. The proposed method is derived from a recent technique used for single component data, which takes into account the wideband characteristics of the signal. The multicomp...

The application of the pre-stack depth migration (PSDM) method using deep seismic reflection data is still a challenge. In this paper, dataset collected from Bohai Bay Basin used to test applicability method. After improving signal-to-noise ratio prestack gathers and building an accurate velocity model capturing lateral vertical variations, high-quality profile obtained. This shows detailed cru...

Time-lapse seismic data is used to monitor subsurface changes occurring between consecutive surveys. One way to look at the differences is to create images from each survey and simply subtract them to obtain a difference. It is possible to model image differences directly from the slowness change between two surveys: this leads to a forward modeling operator that essentially performs differenti...