Estimation of Q-factor based on prestack CMP gathers and its application to compensate attenuation effects
Sam Zandong Sun, Yonggang Wang, Xuekai Sun, Hangyu Yue, Wenkui Yang, Chenjian Li · 2014
Summary Although prestack seismic data contains more abundant information in amplitude and traveltime than the poststack seismic data for estimating Q values, the waveforms or spectrum of reflectors are strongly altered by nearby reflectors or side lobes. It will interfere the calculation of spectrum and thus degrade the precision of Q estimation, several methods based on prestack data have been developed to solve this problem. Different from the usual, we propose a method based on the Modified S-Transform (MST) to estimate Q factor values from prestack CMP gathers. Q estimations can be obtained with regression analysis based on the relation of spectral ratio slope and the square of offset. Then, we utilize the resultant Q model to compensate the amplitude loss and correct phase distortion. Results from synthetic data and real data demonstrate that MST is more capable in improving the accuracy of Q value estimations. Applications on inverse Q filtering and prestack Q migration greatly improve the imaging resolution. While Q migration can obtain amplitude preserved gathers and corrects the phase to some extent, which contributes to better reservoir descriptions.