| 摘要 |
<p>21.579 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 s1...sn detected at respective levels x1...xn, in determining the propagation time tk of the acoustic waves from the level x1 to each level xk, in advancing the signals sk by the time tk in relation to s1 and in adding s1 and the signals sk thus shifted to obtain a sum z1, in calculating a sum y1 of s1 and of the signals sk delayed by the time tk in relation to s1, in generating a signal u?, defined as an optimum estimation of the upgoing wave component, from the sums y1 and z1, and in repeating these operations until the signal U?-n+1 is obtained.</p> |
