Automatic NMO Correction and Full Common Depth Point NMO Velocity Field Estimation in Anisotropic Media

We proposed a method to automatically NMO correct prestack seismic reflection data, that is sorted by CDP gathers and to estimate the normal move-out velocity (Vnmo) as a full CDP velocity field that instantaneously varies with offsets/azimuths. The method is based on doing a predefined number of NMO velocity iterations using linear vertical interpolation of different NMO velocities at each seismic trace individually. At each iteration, the seismic trace is shifted and multiplied by the zero offset trace followed by the summation of the product, then after all the iterations are done, the one with the maximum summation value is chosen, which is assumed to be the most suitable NMO velocity trace that accurately flattens seismic reflection events. Another new, simple and fast method is also introduced to estimate the anisotropic effect from the extracted NMO velocity field. The method runs by calculating the spatial variation of the estimated NMO velocities at each arrival time and offset/azimuth, therefore, instantaneously estimate the anisotropic effect.The method has been tested on a range of different real and synthetic data examples.