Visco-Acoustic Reverse-Time Migration based on the Stereo-Modeling Operator
J. Li, Z. Wang and D.H. Yang
Event name: 80th EAGE Conference and Exhibition 2018
Session: Seismic Imaging - Theory I
Publication date: 11 June 2018
Info: Extended abstract, PDF ( 2.05Mb )
Price: € 20
Viscous effects causes seismic energy attenuation and waveform distortion. Conventional acoustic migration cannot account for this effect, which may produce images with poor illumination, reduced resolution, and wrong placement of reflectors. Reverse time migration (RTM) based on the visco-acoustic wave equation is an effective way to image subsurface media. Solving the wave equation accurately and efficiently affects the RTM results. Stereo-modeling methods have great ability in suppressing numerical dispersion, thus can improve computational efficiency with coarse grids. Based on the stereo-modeling operator, we derive a nearly-analytic central difference (NACD) method (4th-order accuracy in both time and space) to solve the visco-acoustic wave equation. The efficiency test shows it can suppress the numerical dispersion effectively and is more efficient compared with Lax-Wendroff correction (LWC) method with the same accuracy. The acoustic and visco-acoustic RTM based on NACD is performed on the fault and Marmousi models. The results show that the application of NACD in RTM improves the accuracy and the resolution of images. Moreover, the images obtained by visco-acoustic RTM are clearer and have higher resolution compared with images obtained by acoustic RTM because the viscous effects are considered and compensated.