Multifocusing as a method of improving subsurface imaging

Abstract

Imaging the subsurface, the ultimate goal of the seismic method, can be done in different ways and in different domains: time or depth. Although depth migration has become almost mandatory in areas of complex geology— because it accounts for traveltime nonhyperbolic moveout, it has, in fact, quite a limited purpose—to convert seismic data from one form to another for a given velocity model. Time imaging provides sufficient information for a subsurface of moderate complexity. Moreover, even for complex areas that require depth migration for correct subsurface imaging, time imaging usually constitutes a key first step that facilitates the estimation of a velocity model for depth imaging. For these reasons, improving the quality of time imaging is a focus of intensive research. A recent advance is multifocusing (MF), a method with the potential to greatly improve the quality of time imaging.