Abstract: A seismic exploration method is disclosed for filtering the signals produced by a detector placed at different depths in a well in response to an emission of acoustic waves from a source on the surface: the signals comprising downgoing wave components and upgoing wave components.The filtering consists in sampling from among the N signals to be processed a group of n signals s.sub.1 . . . s.sub.n detected at respective levels x.sub.1 . . . x.sub.n, in determining the propagation time t.sub.k of the acoustic waves from the level x.sub.1 to each level x.sub.k, in both advancing and delaying the signals s.sub.k by the time t.sub.k in relation to s.sub.1, in adjusting the signals for the effects of the acoustic impedance of the formation, in combining s.sub.1 and the signals s.sub.k thus shifted and adjusted to obtain a sum z.sub.1 ', in calculating a sum y.sub.1 ' of s.sub.1 and of the thus delayed and adjusted signals s.sub.k, and in generating a signal u.sub.1.sup.