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| | Abstract | | Recent attenuation measurements from sonic waveforms have proven the effectiveness in investigating the detailed correlation between the observed high-resolution sonic attenuation estimates and physical properties in a target zone. In the present paper, to further improve the performance of the MMFS (modified median frequency shift) method, we proposed an attenuation estimation method for sonic waveforms by combining CMP approach and SI. The proposed methods were applied to synthetic and field sonic waveforms acquired in carbonate rocks to examine and compare the applicability of the proposed methods with that of the conventional MMFS method both in depth resolution and stability of attenuation results. The proposed methods provide higher depth resolution attenuation estimates in comparison with the MMFS method because the transmitter-receiver distance controlling the depth resolution can be shortened by SI. Our numerical experiments also find the trade-off between the resolution and accuracy of attenuation estimates and imply the optimum selection of receiver pairs used for more stable attenuation analysis. Finally, by preliminarily applying the proposed methods to field sonic data, we demonstrate the advantages of the proposed method in the resolution of attenuation estimates and these observations correlate with those of numerical tests. |
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