|
| | Abstract | | We propose seismic interferometry in the image domain as a direct migration method for passive seismic observations. Our image domain interferometry is implemented with a reverse time migration including a wavefield extrapolation and crosscorrelation. In a wavefield extrapolation process, arbitrary time-windowed passive seismic records are propagated forwards from receiver points which become virtual sources, and same records are propagated backwards from other receiver points. Then, by crosscorrelating the extrapolated wavefields, surface-related multiple reflections are focused on the imaging points when satisfying the imaging condition. The image domain interferometry by simultaneous wavefield extrapolation for all receivers is suitable for obtaining daily monitoring images. The common image gathers with all virtual sources reconstructed by the wavefield extrapolation can be used to improve the image quality or to analyze stationary phase and migration velocity. A numerical simulation evaluating repeatability on a time lapse survey shows a possible application of the image domain interferometry to monitor subsurface and detect a small velocity anomaly although we need further study to mute amplitude differences caused by changes of source distribution. |
|
|
|
| |
|