Extracting efficiently angle gathers using Poynting vector during reverse time migration

Reverse time migration has shown its superior performance for imaging the complex subsurface structures, but it needs a more accurate velocity model. Common-image gathers are an important output of prestack depth migration. They not only can provide velocity model for depth migration, but also can provide amplitude and phase information for subsequent subsurface attribute interpretation. In this paper, we have developed a method for extracting angle domain common-image gathers during reverse time migration. In our method, vector wave equation is used to calculate the wavefield, energy flux density vector (Poynting vector) is used to calculate the reflection angle, and finally cross-correlation imaging condition is used to obtain the angle domain common-image gathers. Finally, a model and a field marine data are done to show the effectiveness and advantages of this new method.