A B S T R A C T A new type of seismic imaging, based on Feynman path integrals for waveform modelling , is capable of producing accurate subsurface images without any need for a reference velocity model. Instead of the usual optimization for traveltime curves with maximal signal semblance, a weighted summation over all representative curves avoids the need for velocity analysis, with its common...

Multicomponent acquisitions offer the opportunity to form elastic migration images and to estimate elastic parameters of the subsurface. Compared with better constrained P-wave velocity inversions, it is more difficult to estimate the S-wave velocity due to strong nonlinearities introduced by converted S-waves. We have developed an iterative S-wave velocity inversion method guided by image regi...

I apply the iterative hyperbolic Radon transform to CMP gathers to create a velocity panel where multiples and primaries are separable. The velocity panel is created using three different inversion schemes: (1) l2 norm inversion, (2) l1 norm inversion and (3) l1 norm with l1 regularization inversion. The third technique is particularly efficient at separating primaries and multiples in the pres...

I present a simple method for computing angle-domain Common Image Gather (CIG) using prestack reverse time migration. The proposed method is an extension of the method proposed by Rickett and Sava (2001) to compute CIGs by downward-continuation shotprofile migration. I demonstrate with a synthetic example the use of the CIG gathers for migration velocity updating. A challenge for imaging both o...

An accurate depth-velocity model is the key for obtaining good quality and reliable depth images in areas of complex geology. In such areas, velocity-model definition should use methods that describe the complexity of wavefield propagation, such as focusing and defocus ing, multiple arrivals, and frequency-dependent velocity sensitivity. Wave-equation tomography in the image space has the abili...

We introduce a method for improving the image in areas of poor illumination using leastsquares inversion regularized with dip penalty filters in one and two dimensions. The use of these filters helps to emphasize the weak energy that exists in poorly illuminated areas, and fills-in gaps by assuming lateral continuity along the reflection-angle axis and/or the midpoint axes. We tested our regula...

This paper explores the relationship between velocity uncertainty and AVO-related seismic attributes in a dataset from the Blake Outer Ridge, offshore from Florida and Georgia. From an initial velocity model, several realizations were generated that are perturbations of the original velocity model. Prestack wave-equation migration was applied to the data for each velocity realization. In the mi...

Prestack Kirchhoff migration using first arrival traveltimes has been shown to fail in areas of complex structure. I propose a new method for calculating traveltimes that estimates the traveltime of the maximum energy arrival, rather than the first arrival. The method estimates a traveltime that is valid in the seismic frequency band, not the usual high frequency approximation. Instead of solvi...