Time-reversal scatterer detection in 3D media using Kirchhoff back propagation

Medium- and small- scale (less than the seismic wavelength) subsurface elements such as faults, pinchouts, karsts, fractures, fluid contact etc. play an important role in seismic exploration and production. They act as scattering objects which can be effectively detected and located using the time reversal (TR) principle. In this study, we propose a 3D TR algorithm to spatially localize subsurface scatterers. The method uses numerical back propagation of the time-reversed registered wavefield by Kirchhoff modeling. The back propagation step can be followed by focusing analysis of each obtained snap shot. Alternatively, resulting depth image is computed as a simple integration of the energy or semblance over all back propagated snapshots. The usefulness of the method is demonstrated using both synthetic and field data examples.