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| | Abstract | | The geometrical spreading effect causes the variation of waveform amplitudes especially in fast formations, leading to the violation of the assumption of the constant geometrical spreading effect over all depths. We investigate the influence of geometrical spreading on attenuation estimation from sonic logging waveforms by using both MMFS (modified median frequency shift) and SI (seismic interferometry)+CMP (common mid-point)+MMFS methods. Our numerical experiments demonstrate that the geometrical spreading effect largely influences the attenuation profile generated from the MMFS method, whereas he attenuation profile generated from the SI+CMP+MMFS method is less influenced by the geometrical spreading effect than that from the MMFS method. The reason why the SI+CMP+MMFS method is superior in the less influence of geometrical spreading effect to the MMFS method is that the depth resolution increases because of shortening the separation distance between a transmitter and receiver. |
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