Method for the processing of recordings of signals resulting from a seismic exploration of a medium
First Claim
1. Method for the processing of recordings of signals resulting from a transmission and a reception of acoustic waves propagating into a medium, comprising the steps of:
- grouping the recordings in pairs such that in each pair the two recordings correspond to two acoustic paths including at least one non-common part defining a measuring space and at least one common part;
cross correlating the two recordings of each pair in order to obtain an elementary cross correlation function defining the time taken by the waves of the said pair to travel through the measuring space;
grouping the elementary cross correlation functions in at least one family in which the measuring spaces are included in a same predetermined reference space;
transforming the time variable of the elementary cross correlation functions in order to bring the dimension of their measuring space to the dimension of the reference space;
adding all the transformed cross correlation functions in order to form a sum cross correlation function of which the abscissas of the useful lobes represent the propagation time of the waves over the reference space.
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Abstract
Method for the processing of recordings of signals resulting from a seismic exploration of a medium.
It consists, after grouping recordings in pairs and crosscorrelation of the recordings of each pair, in grouping the elementary crosscorrelation functions thus obtained in at least one family in which the measuring spaces are included in a same predetermined reference space, in transforming the time variables of the said functions in order to bring the measuring space dimension to that of the reference, then in adding the transformed functions.
Application in particular to acoustic logging seismic reflection or refraction.
14 Citations
15 Claims
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1. Method for the processing of recordings of signals resulting from a transmission and a reception of acoustic waves propagating into a medium, comprising the steps of:
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grouping the recordings in pairs such that in each pair the two recordings correspond to two acoustic paths including at least one non-common part defining a measuring space and at least one common part; cross correlating the two recordings of each pair in order to obtain an elementary cross correlation function defining the time taken by the waves of the said pair to travel through the measuring space; grouping the elementary cross correlation functions in at least one family in which the measuring spaces are included in a same predetermined reference space; transforming the time variable of the elementary cross correlation functions in order to bring the dimension of their measuring space to the dimension of the reference space; adding all the transformed cross correlation functions in order to form a sum cross correlation function of which the abscissas of the useful lobes represent the propagation time of the waves over the reference space. - View Dependent Claims (2, 3, 4, 5, 6, 7, 9, 10)
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8. Method for the processing of acoustic signals of the type according to which it consists in:
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transmitting acoustic waves by means of transmission; receiving the waves after they have propagated in the formations surrounding a borehole on means of reception, the said means of transmission and reception defining between them at least three acoustic paths of different lengths; recording during each transmission the totality of the signals received on the means of reception; marking, at the moment of transmission and for each recording, the respective positions of the means of transmission and reception which gave rise to the said recording; grouping all the recordings in pairs such that in a given pair the two acoustic paths corresponding to the two recordings of the said pair have one common end and a non common part; crosscorrelating the two recordings of each pair in order to obtain an elementary crosscorrelation function, characterized in that it consists in; selecting from the elementary crosscorrelation functions a reference crosscorrelation function which corresponds to a reference layer the thickness of which is greater than the geological layer of interest; transforming the time variable of each elementary crosscorrelation function other than the reference crosscorrelation function in order to bring each time variable to the dimension of the time variable of the reference crosscorrelation function; and adding all the transformed crosscorrelation functions and the reference crosscorrelation function in order to form a sum crosscorrelation functions of which the abscissas of the useful lobes are representative of the propagation times of the waves in the reference layer. - View Dependent Claims (11, 12, 13, 14, 15)
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Specification