US 6,639,871 B1Granted

Seismic processing methods

AssigneeCompagnie Generale de Geophysique

InventorsRobert Garotta, Pierre-Yves Granger

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Abstract

A method of processing seismic traces corresponding to two modes of propagation in the subsoil, the method being characterized by the following steps: determining at least one pair of correlated events from the seismic traces corresponding to the two modes respectively; determining the ratio of the differences between the vertical travel times Ts and Tp in the S domain and in the P domain, corresponding to said correlated pairs of events; and determining the values of Ts and Tp over the time interval defined by the two pairs of correlated events so that throughout said time interval, the ratio rt=Ts/Tp is equal to the ratio Vp/Vs of the speeds in the P domain and in the S domain, and so that the mean value of said ratio r over said time interval corresponds to the ratio of the differences between the vertical travel times corresponding to the pairs of correlated events.

Claims8

Dependent claims

A method of processing seismic traces corresponding to modes of propagation in the P domain and in the S domain in the subsoil, in which method:

the vertical travel times in the S domain and in the P domain of at least one correlated event in said two domains is determined from the seismic traces, the method being characterized in that:
for two such events, the ratio between firstly the difference between the vertical travel times of said two events in the S domain, and secondly the difference between the vertical travel times of said two events in the P domain is determined;
and
for different instants of the time interval defined between the vertical travel times of said two events in the S domain, the corresponding vertical travel times in the P domain are calculated, or for different instants of the time interval defined between the vertical travel times of said two events in the P domain, the corresponding vertical travel times in the S domain are calculated while imposing the following two constraints:
for any interval in question, the ratio rt=Ts/Tp is equal to the ratio Vp/Vs of the speeds in the P domain and in the S domain;
and
the mean value of said ratio r over said time interval corresponds to the ratio between firstly the difference between the vertical travel times of said events in the S domain, and secondly the difference between the vertical travel times of said two events in the P domain.

4 more elements

Dependencies are inferred from the claim text.