METHOD FOR SEPARATING MICROSEISMIC SIGNALS FROM SEISMIC SIGNALS EMITTED BY ONE OR SEVERAL SOURCES

摘要

The invention concerns a method for separating microseismic signals from seismic signals acquired in the context of active seismic monitoring operations of underground zones being exploited. It consists in producing seismic recordings from signals emitted by a single or several seismic sources monitored by signals orthogonal relative to one another. In that case the signals are processed to separate the respective contributions of the seismic sources to the received signals and reconstruct the seismograms equivalent to those which would be obtained by separately actuating the seismic sources. The induced microseismic signals (passive seismics) are separated from the seismic signals derived from sources 5 (active seismics) essentially by isolating the contribution of the latter, by comparison with a reference spectral model to the fundamental frequencies emitted and to their respective harmonics, and by reconstructing in the time domain the induced microseismic signals and the signals derived from the seismic sources 5. The invention is applicable to seismic monitoring of underground hydrocarbon or fluid storage reservoirs.