Reverse time migration angle gathers in acoustic anisotropic media using direction vectors

Yang，Kai1,2,3; Zhang，Jianfeng1,2,3

2024-03-01

10.1190/geo2023-0328.1

Geophysics   影响因子和分区

0016-8033

1942-2156

The application of direction vectors in the generation of reverse time migration (RTM) angle gathers in complex acoustic anisotropic media often encounters three main challenges: not pointing to the phase-velocity direction (PVD) of the Poynting vector, inaccuracy due to overlapping wavefields, and instability due to zero points of the direction vector. In general anisotropic media, the standard Poynting vector indicates the group-velocity direction (GVD), whereas reflection and transmission phenomena rely on the PVD. Anisotropy introduces discrepancies between the GVD and the PVD. To overcome this issue, we use the so-called PVD vector to directly calculate the PVD from anisotropic wavefields, eliminating the need for an approximated conversion from the GVD to the PVD. To mitigate the inaccuracy problem, we apply the Hilbert transform-based wavefield decomposition method to separate overlapping wavefields into their up/down components, and then we calculate the PVDs using the separated wavefields. To tackle the instability problem, we incorporate the additionally simulated quadrature wavefield during the wavefield decomposition procedure. By combining the direction vector of the quadrature wavefield with that of the original wavefield, we can eliminate the zero points and thus obtain a stabilized PVD vector. With those problems solved or alleviated, we present a scheme for the generation of anisotropic RTM angle gathers in complex areas. Two numerical examples using synthetic data sets demonstrate our method's effectiveness.

anisotropy gathers migration reverse time migration

SCI ; EI

英语

第一 ; 通讯

GEOSCIENCES

2-s2.0-85184806084

Scopus

1.Southern University of Science and Technology,Shenzhen Key Laboratory of Deep Offshore Oil and Gas Exploration Technology,Shenzhen,China
2.Guangdong Provincial Key Laboratory of Geophysical High-resolution Imaging Technology,Shenzhen,China
3.Southern University of Science and Technology,Department of Earth and Space Sciences,Shenzhen,China

Yang，Kai,Zhang，Jianfeng. Reverse time migration angle gathers in acoustic anisotropic media using direction vectors[J]. Geophysics,2024,89(2):C43-C55.

Yang，Kai,&Zhang，Jianfeng.(2024).Reverse time migration angle gathers in acoustic anisotropic media using direction vectors.Geophysics,89(2),C43-C55.

Yang，Kai,et al."Reverse time migration angle gathers in acoustic anisotropic media using direction vectors".Geophysics 89.2(2024):C43-C55.