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One-way wave propagation in the ray-centred coordinate system for vertical transversely isotropic media

Zhang Bohan, Wang Huazhong

Acta Geophysica

2021

Vol. 69, no. 4

1225--1239

Seismic wave imaging in complex media requires a suitable wave feld simulation method that can accurately describe realmedia wave propagation. Reverse time migration is currently the preferred method; however, it is not optimal for simulating wave feld propagation as it is based in solving the wave equation (qP-wave equation). The objective of this study is to develop a wave propagation simulation method to accurately describe the P-wave energy, which is less afected by complex surface conditions, and easily integrate anisotropy and attenuation by absorption media. Herein, qP-wave propagation is simulated in vertical transversely isotropic (VTI) media using the one-way wave equation in the ray-centred coordinate system (15°), which combines the fexibility of ray theory and accuracy of wave theory to describe wave propagation. Based on the qP-wave equation of VTI media, the wave equation in the ray-centred coordinate system and the one-way wave equation (15°) in the ray-centred coordinate system are derived. The 15° one-way wave equation can simulate the wave propagation process in complex media. Numerical experiments verify that the simulation results for the 15° equation in the ray-centred coordinate system exhibit high accuracy.

Three dimensional angle domain double square root migration in VTI media for the large scale wide azimuth seismic data

Wu Chengliang, Feng Bo, Wang Huazhong, Wang Tianzhen

Acta Geophysica

2020

Vol. 68, no. 4

1021--1037

With the development of oil and gas exploration, the conventional seismic migration imaging technology based on the isotropic assumption no longer meets our current requirements for high-resolution images. Migration in anisotropic media has become an essential requirement for oil and gas exploration. Marine seismic exploration has gradually entered the wide azimuth and high-density seismic data acquisition stage. However, even for current large high-performance computer clusters, it is still very difcult to implement pre-stack depth migration based on shot gathers. Thus, we present a double-square-root (DSR) equation based on three-dimensional (3D) pre-stack depth migration in midpoint-ofset domain for a wide-azimuth dataset in transversely isotropic media with a vertical symmetry axis (VTI media). Considering VTI media, the DSR migra tion requires extensive memory and computation; we adopted the phase-shift plus interpolation approach to improve the computational efciency. Then, we extract the angle-domain common-image gathers (ADCIGs) during DSR migration. For real large-scale seismic data, we designed an efective parallel implementation of 3D DSR migration with ADCIGs outputs. Finally, we applied the proposed angle-domain VTI DSR migration on wide-azimuth SEG/EAGE salt dome-based data and real data from the China South Sea. Numerical and practical data illustrate the efectiveness of the proposed method.