Abstract：Absorption coefficient is an important parameter for reservoir description. The major troubles we have in extracting absorption coefficient from seismic data are amplitude and waveform distortions;they greatly restrict the inversion which is based on reflection amplitude variation or reflection frequency variation. Presented here is a new method which avoids amplitude and uses waveform variation gradient in wave propagation to make the inversion of absorption coefficient. Apparent absorption coefficient and pseudo absorption coefficient are adopted so as to remove the influence which the waveform distortion due to thin bed tuning brings to absorption coefficient extraction. The final instantaneous equivalent absorption coefficient, a true absorption coefficient which reflects real absorptive character of a seismic medium, can be obtained by subtracting the pseudo absorption coefficient(inversely calculated using maximum entropy)from the apparent absorption coefficient we have calculated.
