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Estimation of Time and Spatial Shifts in 4D Seismic Surveys Using Mutual Information and Signal Envelope
- Publisher: European Association of Geoscientists & Engineers
- Source: Conference Proceedings, 79th EAGE Conference and Exhibition 2017, Jun 2017, Volume 2017, p.1 - 5
Abstract
Time and spatial shift estimation in time-lapse seismic data is usually achieved using cross-correlation. While this method works generally well and it is robust in dealing with real data, it has some drawbacks. We propose here two alternative methods based on mutual information and on the signal envelope, with the aim of getting an improved estimation of the temporal and spatial 4D shifts, even in the case of signal phase variations between base and monitor image. We quantify the performances of the proposed methods using synthetic examples, and we also show results of application to a real 4D dataset. From the analysed results, we conclude that the mutual information method gives better results than cross-correlation, but the larger improvements are obtained when computing the envelope of the signal, as it allows well estimating the time shifts in presence of 4D phase variations between base and monitor. Moreover, the results on field data obtained with the envelope-based mutual information method are more closely related to the expected dynamic changes within the reservoir.