Abstract:Compared with anisotropic elastic wave equation, it is more advantageous to use approximate anisotropic qP-wave equation for wave-field numerical simulation and reverse-time migration (RTM). However, the conventional acoustic approximation method usually causes numerical instability in heterogeneous TTI media with rapid dip variation. Therefore we propose in this paper a new approach of wave-field numerical simulation and RTM based on stable first-order qP-wave equations. First based on the exact qP-qSV wave dispersion relation, the new TTI second-order qP-wave equations are derived by introducing an anisotropic control parameter σ, and meanwhile they are transformed into the equivalent first-order stress-velocity form wave equations through introducing the pseudo-velocity components of the wave-fields. Then, we apply the optimal high-order least-squares stagger-grid finite-difference (LS-SGFD) method to solve the stable TTI first-order wave equations and construct the wave-field extrapolators. In this way the accurate wave-field simulation and RTM of anisotropic media are achieved. Model test results show that TTI first-order qP-wave equation can steadily simulate the wave-field propagation features of qP-wave. Utilizing the optimal LS-SGFD method can effectively enhance the modeling accuracy, and further improve the imaging quality.
杨富森, 李振春, 王小丹. TTI介质一阶qP波稳定方程波场数值模拟及逆时偏移[J]. 石油地球物理勘探, 2016, 51(3): 497-505.
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