This paper investigates the applicability of prestack Stolt residual migration when the original image is obtained using an arbitrary velocity model. At its origin, the method is based on an assumption of constant velocity. However, its formulation for depth-migrated images involves a ratio of the reference and target velocities; therefore, for residual migration it is completely irrelevant if ...

This paper presents a method of Stolt residual migration applicable to prestack data. The method’s main merit is that instead of requiring an assumption about the magnitude of the new velocity model to which we want to residually migrate, it only calls for an assumption about the ratio of the reference velocity to the new one. Since the method is, in essence, a Stolt-stretch technique, it inher...

Common-azimuth migration (CAM) is an attractive solution for 3-D prestack imaging. It reduces the full 5-D phase-shift operator to 4-D through the stationary-phase approximation, lowering the computational cost. However, this assumption yields constraints in the downward-continuation process that can limit accuracy. Those errors are estimated in this paper by comparison to other wave-equation m...

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...

Summary The hydrocarbon prospects in mountainous areas require solving a most challenging problem in seismic imaging --irregular topography associated with a rugged terrain, complexity of the nearsurface that includes high-velocity layers and outcrops with significant lateral velocity variations, complexity of the overburden, and the complexity of the target imbricate structures themselves. We ...

Traveltime computation is an important part of seismic imaging algorithms. Conventional implementations of Kirchhoff migration require precomputing traveltime tables or include traveltime calculation in the innermost computational loop . The cost of traveltime computations is especially noticeable in the case of 3-D prestack imaging where the input data size increases the level of nesting in co...

3-D prestack common-azimuth depth migration has strong potential for accurately imaging complex media and correctly handling multi-pathing. Here, we apply the technique to a North Sea real data containing a salt dome. The results obtained demonstrate the suitability of the method for complex media. A detailed analysis of associated angle-domain common-image gathers shows opportunities for impro...

Traveltime computation is an important part of seismic imaging algorithms. Conventional implementations of Kirchhoff migration require precomputing traveltime tables or include traveltime calculation in the innermost computational loop . The cost of traveltime computations is especially noticeable in the case of 3-D prestack imaging where the input data size increases the level of nesting in co...

Many processes in seismic data analysis and seismic imaging can be identified with solution operators of evolution equations. These include data downward continuation and velocity continuation. We have addressed the question of whether isochrons defined by imaging operators can be identified with wavefronts of solutions to an evolution equation. Rays associated with this equation then would pro...

In this report, we introduce a new wave-equation method of migration velocity analysis (MVA). The method is based on the linear relation that can be established between a perturbation in the migrated image and the generating perturbation in the slowness function. Our method consists of two steps: we first improve the focusing of the migrated image and then iteratively update the velocity model ...