Processing method for obtaining zero-offset seismic data by depth domain stacking

摘要

The object of the method according to the invention is to synthesize zero-offset seismic data from data acquired within the scope of three-dimensional (or possibly two-dimensional) multiple-offset seismic reflection prospecting operations in a subsurface environment. It mainly comprises selection of a distribution model of the velocities in the environment, seismic data prestack migration (stacking of the multiple-offset seismic events is achieved in the depth domain), and synthesis of zero-offset seismic data in the time domain by applying to the results obtained with this depth domain stacking a known modelling technique, for example that referred to as explosive reflector technique. This procedure allows zero-offset extrapolation of the seismic data obtained for non-zero offsets, even in case of great lateral velocity changes in the environment; the stacking performed allows then a much greater improvement of the signal-to-noise ratio than that based on the conventional stacking based on dynamic corrections (with or without dip corrections). Application: 3D imagery of geologic structures for example.