Optimum Split-step Fourier Migration Method

With the development of exploration and exploitation in the oil area, the seismic exploration focuses on the accurate imaging and high computational costs. The quality of accurate imaging and the efficiency of calculating depend on the migration method. In this paper, the optimum Split-step Fourier migration method is researched. On the basics of the optimal principle, we can choose the optimal velocity by the Scanning method for the accurate imaging.In the paper, chapter one shows the background of seismic exploration, the development and history of the seismic data migration and the development of wave equation migration. Chapter two introduces the Split-step Fourier method, and shows the method how to implement in the computer. Chapter three describes the synthetic source and synthetic source record. The forward modeling illustrates the synthetic source and synthetic source record satisfy the wave equation as the same as the shot record, at the same time they also improve the computational costs. On the basis of chapter one and two, chapter four shows two methods of optimum Split-step Fourier migration method. The aim function is designed by analyzing the error in the first method. The velocity subarea is designed by using more reference slowness to choose the optimal velocity in order to reduce the relative error in the other method. A numerical test of wave equation prestack depth migration on the international standard SEG/EAGE 2D salt dome model shows that the optimum split-step Fourier migration method has more accurate imaging than the conventional split-step migration method, and can produce high-quality images in the presence of sharp discontinuities of the velocity field.