The elastic wave equation forward modeling and wave-field characteristic analysis for the salt dome model
Di Bang-rang1,2, Pei Zheng-lin1,3
1. CNPC Key Lab of Geophysics,China University of Petroleum,Beijing City,102249,China;
2. Beijing City Key Lab of Earth Prospecting and Information Technology,China University of Petroleum,Beijing City,102249,China;
3. Beijing North Newtech Petrotech Ltd.,Beijing City,100192,China
Abstract：In this paper the forward modeling for theoretical model and field model of the salt dome structure was conducted by using staggered grid high-order finite difference method of the inhomogeneous medium elastic wave equation and acoustic equation,by application of the single-frequency harmonic source and through the elastic wave equation numerical simulation,the divergence field,the vortex field,the kinetic energy field and the potential energy flow field for the elastic wave were acquired,the energy and the propagation characteristics of the elastic wave were quantitatively delineated.Through the wave field snapshot,single shot record and the zero-offset sections,the influence of the complicated salt dome structure to the seismic response were analyzed in detail.The numerical simulation results for the theoretical model and field model show the following conclusions:(1).The elastic wave divergence field and the vortex field respectively described the P-wave wave-field energy characteristics and the converted wave wave-field characteristics,the kinetic energy field and the potential energy flow field then delineated the total field energy characteristics and its propagation characteristics,compared with the acoustic wave equation,the elastic wave numerical simulation could more realistically characterized the total field energy characteristics and its responses,(2).The salt dome caused obvious energy focusing effects for the reflection wave-field and the scattered wave-field,it imposed great modulation on the wavefront of the transmitted wave,the reflection wave-field and the scattered wave-field which were caused by the salt dome,the energy shielding from the high velocity salt dome could form the energy shadow zone,and then the energy shadow zone may affect the deep reflection signal and lowed down the signal to noise ratio.(3).Compared with the Kirchhoff pre-stack time migration,the Kirchhoff pre-stack depth migration could more accurately image for the steep structures beside the salt dome and under the salt dome,however for the scattered wave from the left side and right side within the salt dome,the imaging quality is not great,this is due to the fact that the Kirchhoff integration migration method is based on the ray tracing algorithm,as a result the imaging method for the scattered wave should be developed.
狄帮让, 裴正林. 盐丘模型弹性波方程正演模拟及波场特征分析[J]. 石油地球物理勘探, 2010, 45(6): 826-832.
Di Bang-rang, Pei Zheng-lin. The elastic wave equation forward modeling and wave-field characteristic analysis for the salt dome model. OGP, 2010, 45(6): 826-832.
