Elastic reverse time migration based on nested triangular mesh in 2D isotropic media

Lu, Yongming1; Lei, Tao2; Liu, Qiancheng3; Zhang, Jianfeng2; Zang, Nan2

2024-07-25

10.1093/jge/gxae058

JOURNAL OF GEOPHYSICS AND ENGINEERING   影响因子和分区

1742-2132

1742-2140

Reverse time migration (RTM) based on a two-way wave equation is an important imaging tool that has been widely used in exploration geophysics. It offers distinct advantages in handling complex geological structures. Moreover, elastic reverse time migration (ERTM) can produce more physically meaningful images for subsurface and has received increasing attention in recent years. However, rugged topography presents challenges in the reconstruction of subsurface structures for ERTM. To overcome this problem, we introduce the grid method for topography ERTM, which is an unstructured mesh-based algorithm. However, the conventional gird method for RTM is implementing by discretizing the model into small meshes, leading to high computational cost. To address this problem, we introduce the grid method based on nested unstructured meshes to implement ERTM with complex surface topography. Low-order small meshes, due to their fine scale, can accurately depict complex surface topography. However, their generation process is relatively time consuming. By contrast, high-order large meshes contain many similar small meshes internally, which can be processed in parallel, resulting in higher computational efficiency. Therefore, we propose the following strategy: for the receiver wavefield, several layers on surface discretized by the small meshes are used to place receivers and remaining layers discretized by the large meshes to improve computational efficiency. For the source wavefield, only the large meshes are used because the spacing of the shot is relatively large. In this way, we ensure the accurate description of complex surface topography for the implementation of ERTM with high computational efficiency. Finally, the effectiveness of our method is validated through experiments on three models with complex topography.

nested triangular mesh elastic reverse time migration topography

SCI

英语

其他

University Stability Support Program of Shenzhen-General Project[20231128113233002] ; National Science Foundation of China["42104119","42104106"] ; Mathematical Model and Machine Learning Algorithm of Seismic Surface Waves[2021KTSCX145]

Geochemistry & Geophysics

Geochemistry & Geophysics

WOS:001275776300001

OXFORD UNIV PRESS

Web of Science

1.Shenzhen MSU BIT Univ, MSU BIT SMBU Joint Res Ctr Appl Math, Shenzhen 518172, Peoples R China
2.Southern Univ Sci & Technol, Dept Earth & Space Sci, Shenzhen 518055, Peoples R China
3.Chinese Acad Sci, Inst Geol & Geophys, State Key Lab Lithospher Evolut, Beijing 100029, Peoples R China

Lu, Yongming,Lei, Tao,Liu, Qiancheng,et al. Elastic reverse time migration based on nested triangular mesh in 2D isotropic media[J]. JOURNAL OF GEOPHYSICS AND ENGINEERING,2024,21(4).

Lu, Yongming,Lei, Tao,Liu, Qiancheng,Zhang, Jianfeng,&Zang, Nan.(2024).Elastic reverse time migration based on nested triangular mesh in 2D isotropic media.JOURNAL OF GEOPHYSICS AND ENGINEERING,21(4).

Lu, Yongming,et al."Elastic reverse time migration based on nested triangular mesh in 2D isotropic media".JOURNAL OF GEOPHYSICS AND ENGINEERING 21.4(2024).