COMPARISON OF WAVE EQUATION MIGRATION METHODS WITH PHASE ENCODING

Prestack migration algorithms are usually divided into two classes: ray-tracing based migration methods and wave-equation methods. The latter methods provide more accurate migration images, especially in complex geological areas, but they are the relatively expensive compared with ray-based migration methods. In this work, I test the phase encoding strategy on three types of one-way wave equation methods for prestack depth migration: Split-Step Fourier method (SSF), Phase-Shift-Plus-Interpolation method (PSPI), and the Fourier Finite-Difference method (FFD). 2D algorithms were tested on the SEG/EAGE salt model data for the purpose of drastically reducing the computational time. Results show that computational effort is obviously reduced but at the expense of reduced image quality. For the 2D SEG/EAGE data, acceptable images are achieved at 15 the cost of stan-dard migration if phase encoding is used. 3D algorithms are also implemented and being tested on the SEG/EAGE salt model