Time-shift imaging condition for converted waves
نویسندگان
چکیده
A typical imaging condition for seismic reflection data involves source and receiver wavefield matching, e.g. by cross-correlation, at every image location. This statement is true no matter how the two wavefields are reconstructed, for example by one-way wavefield extrapolation, or two-way reverse-time extrapolation, or Kirchhoff integral methods. This statement is also true when the source and receiver wavefields are reconstructed using different velocity models, as is the case for imaging of converted waves. Angle-dependent reflectivity information can be extracted from the source and receiver wavefield by retaining multiple lags of the imaging cross-correlation, i.e. by analyzing the match of wavefields shifted relative to one-another. Wavefields can be shifted in space (3D) or in time (1D), and each shift method has an associated angle-decomposition method. This paper explores the various types of imaging condition using spaceand time-shifts and derives relations for angle decomposition for converted-wave imaging.
منابع مشابه
Generalized imaging conditions for wave-equation migration
A typical imaging condition for seismic reflection data involves source and receiver wavefield matching, e.g. by cross-correlation, at every image location. This statement is true no matter how the two wavefields are reconstructed, for example by one-way wavefield extrapolation, or two-way reverse-time extrapolation, or Kirchhoff integral methods. This statement is also true when the source and...
متن کاملConverted-waves imaging condition for elastic reverse-time migration
Polarity changes in converted-wave images constructed by elastic reverse-time migration causes destructive interference after stacking over the experiments of a seismic survey. We derive a simple imaging condition for converted waves imaging designed to correct the image polarity and reveal the conversion strength from one wave mode to another. Our imaging condition exploits pure Pand S-modes o...
متن کاملImaging condition for elastic RTM
Polarity changes in converted-wave images constructed by elastic reverse-time migration causes destructive interference after stacking over the experiments of a seismic survey. The polarity reversal is due to the fact that S-mode polarization changes as a function of direction, and therefore the imaged reflectivity reverses sign at normal incidence. We derive a simple imaging condition for conv...
متن کاملScalar imaging condition for elastic reverse time migration
Polarity changes in converted-wave images constructed by elastic reverse time migration cause destructive interference after stacking over the experiments of a seismic survey. This polarity reversal is due to PS and SP reflectivities reversing sign at certain incidence angles, e.g., at normal incidence in isotropic media. Many of the available polarity correction methods are complex and require...
متن کاملRobustness of the scalar elastic imaging condition for converted waves
For elastic reverse-time migration, one constructs elastic source and receiver wavefields using a source function and multi-component data, and then applies an imaging condition to the reconstructed wavefields. A widely used imaging condition is crosscorrelation of individual wave modes separated in both wavefields, e.g., compressional (P) waves and shear (S) waves. One difficulty in elastic mi...
متن کامل