Extended local Rytov Fourier migration method

There is a vital need for an efficient and accurate migration method capable of imaging large 3D complex structures which are difficult for a ray-tracing based Kirchhoff migration method to image. We develop a novel depth migration method termed the extended local Rytov Fourier migration method. It is based on the scalar wave equation and a local application of the Rytov approximation within each extrapolation interval. The method is efficient due to the use of a Fast Fourier Transform algorithm. While it is similar in implementation to the split-step Fourier migration approach, it is more accurate and can handle amplitudes of wavefields more reliably than the split-step Fourier method. The stability of the method is controlled more easily than that of the extended local Born Fourier method that we previously investigated. Migration examples for a 2D slice of the SEG/EAGE model and the Marmousi model are given to demonstrate the method.