A modified excitation amplitude imaging condition for prestack reverse time migration

作者：Gu, Bingluo^*; Liu, Youshan; Ma, Xiaona; Li, Zhiyuan; Liang, Guanghe

来源：Exploration Geophysics, 2015, 46(4): 359-370.

DOI：10.1071/EG14039

• excitation amplitude imaging condition
• modified shortest path method
• reverse time migration
• traveltime constraint

In wave-equation-based migration, the imaging condition is an important factor that impacts migration accuracy and efficiency. Among the commonly used imaging conditions, the excitation amplitude imaging condition has high resolution, accuracy and low storage and input/output burden when compared with others. However, the excitation amplitude extracted by this imaging condition in its current form will produce a distorted migration image for certain scenarios. In this paper, a modified excitation amplitude imaging condition is proposed that addresses the above problem and produces migrated images free from distortion for complicated geologic models. In this paper, we propose a method to effectively use the modified shortest path method (MSPM) for extracting the maximum amplitude around the first-arrival events. Then, the excitation amplitude imaging condition is applied to obtain a continuous and clear migration image. This process can, to some extent, improve the distorted migration image produced by the traditional excitation amplitude imaging condition. Some numerical tests with synthetic data of Sigsbee2a and Marmousi-II models show that the improvement is feasible and effective in complex-structure media.

• 出版日期2015-12
• 单位中国科学院地质与地球物理研究所兰州油气资源研究中心; 中国科学院大学; 中国科学院地质与地球物理研究所