Finite Difference Method Of Seismic Wave Field Simulation And Reverse Time Migration

Seismic Numerical simulation is the important basis for Seismic exploration and seismology,is a numerical simulation of seismic wave propagation in the medium. Seismic wave field forwardmodeling study includes two core theory, one study of seismic wave theory of dynamicalcharacteristics, and second is to study the kinematic characteristics of seismic wave ray theory. Asthe seismic wave theory used in natural earthquake and seismic exploration, seismic simulation wasproduced, and with the development of seismic wave theory and computer technology, seismicnumerical simulation technology has also been rapid development from1960s, it has formed manymodern seismic numerical simulation technology, such as the finite difference method, finiteelement method, virtual spectrum and the integral equation method and so on in present.Staggered grid higher order finite difference can substitute staggered grid for the generalrectangle difference grid, obtain the difference finite of sufficient higher order spatial precision andtimer resolution by means of half grid calculating. Firstly, the Taylor series was expanded and thestaggered grid finite difference, absorbing boundary method based on the Eigen value analysis wereused to get the difference format of equations for elastic waves and every boundary and angularpoint by analysis the request of stability and dispersion. This format could obtain arbitrary accuracyto implement the2-D elastic wave numerical simulation with the staggered grid finite difference invarious kinds of complex geologic model. The numerical experiment results indicate that thisstaggered grid finite difference had the characters of high simulation precision, strong commonalitygood stability and so on.Seismic migration is the core content of reflection seismology. Based on wave equation,Seismic migration put phase axis homing to its correct spatial location and focus energy to thescattering point diffraction in order to eliminate distortion in the reflection records. Reverse-timemigration can be achieved, when we use wave equation to do reverse extrapolation for seismic dataon the timeline. In the migration processing, wave field will exist as a vector instead of simplesuperposition of the scalar wave. In this paper, I describe the basic theory of reverse-time migration,solve the two-way wave equation with high-order finite difference, derive the high-order finitedifference wavefield continuation formula, and achieve poststack reverse-time migration using thisformula. Cost Calculator model data show that this method has high precision imaging, high lateralresolution, without limitation inclination suitable for lateral velocity variation and complexity ofthe structural model and so on.