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Improvement of Reverse-time Migration using Homogenization of Acoustic Impedance
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  • Journal title : Geophysics and Geophysical Exploration
  • Volume 19, Issue 2,  2016, pp.76-83
  • Publisher : Korean Society of Earth and Exploration Geophysicists
  • DOI : 10.7582/GGE.2016.19.2.076
 Title & Authors
Improvement of Reverse-time Migration using Homogenization of Acoustic Impedance
Lee, Gang Hoon; Pyun, Sukjoon; Park, Yunhui; Cheong, Snons;
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 Abstract
Migration image can be distorted due to reflected waves in the source and receiver wavefields when discontinuities of input velocity model exist in seismic imaging. To remove reflected waves coming from layer interfaces, it is a common practice to smooth the velocity model for migration. If the velocity model is smoothed, however, the subsurface image can be distorted because the velocity changes around interfaces. In this paper, we attempt to minimize the distortion by reducing reflection energy in the source and receiver wavefields through acoustic impedance homogenization. To make acoustic impedance constant, we define fake density model and use it for migration. When the acoustic impedance is constant over all layers, the reflection coefficient at normal incidence becomes zero and the minimized reflection energy results in the improvement of migration result. To verify our algorithm, we implement the reverse-time migration using cell-based finite-difference method. Through numerical examples, we can note that the migration image is improved at the layer interfaces with high velocity contrast, and it shows the marked improvement particularly in the shallow part.
 Keywords
Migration;reflection energy;acoustic impedance;fake density;cell-based finite-difference method;
 Language
Korean
 Cited by
 References
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