Kirchhoff PSDM angle-gather generation based on the traveltime gradient

• Published in: Applied geophysics Vol. 12; no. 1; pp. 64 - 72
• Main Authors: Liu, Shao-Yong, Wang, Hua-Zhong, Liu, Tai-Chen, Hu, Ying, Zhang, Cai
• Format: Journal Article
• Language: English
• Published: Heidelberg Chinese Geophysical Society 01.03.2015; Springer Nature B.V; School of 0cean and Earth Sience, Tongji University, Shanghai 200092, China%Research Institute of Petroleum Exploration & Development, PetroChina, Beijing 100083, China
• Subjects: Earth and Environmental Science; Earth Sciences; Geophysics; Geophysics/Geodesy; Geotechnical Engineering & Applied Earth Sciences; Image processing systems; Mathematical analysis; Mathematical models; Migration; Receivers; Reflection; Shot; Statistical analysis; Three dimensional; Travel time; angle domain; common-image gathers; Kirchhoff prestack depth migration; migration velocity analysis; ADCIGs
• ISSN: 1672-7975; 1993-0658
• DOI: 10.1007/s11770-014-0470-8

Angle-domain common-image gathers (ADCIGs) are the basic data in migration velocity analysis (MVA) and amplitude variation with angle (AVA) analysis. We propose a common-angle gather-generating scheme using Kirchhoff PSDM based on the traveltime gradient field. The scheme includes three major operations: (1) to calculate the traveltime field of the source and the receiver based on the dynamic programming approach; (2) to obtain the reflection angle according to the traveltime gradient field in the image space; and (3) to generate the ADCIGs during the migration process. Because of the computation approach, the method for generating ADCIGs is superior to conventional ray-based methods. We use the proposed ADCIGs generation method in 3D large-scale seismic data. The key points of the method are the following. (1) We use common-shot datasets for migration, (2) we load traveltimes based on the shot aperture, and (3) we use the MPI and OpenMp memory sharing to decrease the amount of input and output (I/O). Numerical examples using synthetic data suggest that the ADCIGs improve the quality of the velocity and the effectiveness of the 3D angle-gather generation scheme.