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AssigneeSchlumberger Technology Corporation
InventorSeeman Bronislaw
Estimating the term…
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.l . . . s.sub.n detected at respective levels x.sub.l . . . x.sub.n, in determining the propagation time t.sub.k of the acoustic waves from the level x.sub.l to each level x.sub.k, in advancing the signals s.sub.k by the time t.sub.k in relation to s.sub.l and in adding s.sub.l and the signals s.sub.k thus shifted to obtain a sum z.sub.l, in calculating a sum y.sub.l of s.sub.l and of the signals s.sub.k delayed by the time t.sub.k in relation to s.sub.l, in generating a signal u.sub.l *, defined as an optimum estimation of the upgoing wave component, from the sums y.sub.l and z.sub.l, and in repeating these operations until the signal U.sub.N *.sub.-n+1 is obtained.
A seismic exploration method for determining characteristics of a geological formation by obtaining a plurality of signals (s.sub.k) derived from a respective plurality of different positions within a borehole that traverses said geological formation and by combining said plurality of signals, comprising:
Dependencies are inferred from the claim text.