However, the prediction model is not adequate in the time-offset domain, because the lag of the water-bottom multiples is not constant on a non-0 offset trace. Actually, this lag is a function of the angle of incidence of the wavefront at the receiver. As the parameter is constant along a ray, this lag depends only upon the p-parameter of the incident ray. So, to make the prediction model more appropriate, it is better to transform the data to the domain with a slant-stack transform, and apply the prediction process in this domain.
Calling VW the water velocity, the variation of the lag L with the p-parameter is given by the relationship:
Thus, after having transformed the input gather to the domain, I will apply the adaptive algorithms on each trace, with yT=ZLxT, and L given by the previous relation. However, I recognize that this method should not be efficient for large p-parameters, because the lag L will be very small (close to 1): the process will try at the same time to remove the multiples and to compress the signal. But for my purpose, which is a comparison between different adaptive methods, I consider it is sufficient.